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变速器介绍外文文献翻译、中英文翻译、外文翻译

变速器介绍外文文献翻译、中英文翻译、外文翻译

附录附录A 英文文献Transmission descriptionTransmission gearbox's function the engine's output rotational speed is high, the maximum work rate and the maximum torque appears in certain rotational speed area. In order to display engine's optimum performance, must have a set of variable speed gear, is coordinated the engine the rotational speed and wheel's actual moving velocity. The transmission gearbox may in the automobile travel process, has the different gear ratio between the engine and the wheel, through shifts gears may cause the engine work under its best power performance condition. Transmission gearbox's trend of development is more and more complex, the automaticity is also getting higher and higher, the automatic transmission will be future mainstream.Automotive Transmission's mission is to transfer power, and in the process of dynamic change in the transmission gear ratio in order to adjust or change the characteristics of the engine, at the same time through the transmission to adapt to different driving requirements. This shows that the transmission lines in the automotive transmission plays a crucial role. With the rapid development of science and technology, people's car is getting higher and higher performance requirements, vehicle performance, life, energy consumption, such as vibration and noise transmission depends largely on the performance, it is necessary to attach importance to the study of transmission.Transmission gearbox's pattern the automobile automatic transmission common to have three patterns: Respectively is hydraulic automatic transmission gearbox (AT), machinery stepless automatic transmission (CVT), electrically controlled machinery automatic transmission (AMT). At present what applies is most widespread is, AT becomes automatic transmission's pronoun nearly.AT is by the fluid strength torque converter, the planet gear and the hydraulic control system is composed, combines the way through the fluid strength transmission and the gear to realize the speed change bending moment. And the fluid strength torque converter is the most important part, it by components and so on pump pulley, turbine wheel and guide pulley is composed, has at the same time the transmission torque and the meeting and parting function.And AT compare, CVT has omitted complex and the unwieldy gear combination variable transmission, but is two groups of band pulleys carries on the variable transmission. Through changes the driving gear and the driven wheel transmission belt's contact radius carries on the speed change. Because has cancelled the gear drive, therefore its velocity ratio may change at will, the speed change is smoother, has not shifted gears kicks the feeling.AMT and the hydraulic automatic transmission gearbox (AT) is the having steps automatic transmission equally. It in the ordinary manual transmission gearbox's foundation, through installs the electrically operated installment which the microcomputer controls, the substitution originally coupling's separation which, the joint and the transmission gearbox completes by the manual control elects to keep off, to shift gears the movement, realizes fluid drive.Manual transmission gear mainly uses the principle of deceleration. Transmission within the group have different transmission ratio gear pair, and the car at the time of shift work, that is, through the manipulation of institutions so that the different transmission gear pair work. Manual transmission, also known as manual gear transmission, with axial sliding in the gears, the meshing gears through different speed to achieve the purpose of torque variation. Manual shift transmission can operate in full compliance with the will of the driver, and the simple structure, the failure rate is relatively low, value for money.Automatic transmission is based on speed and load (throttle pedal travel) fortwo-parameter control gear in accordance with the above two parameters to automatically take-off and landing. Automatic transmission and manual transmission in common, that is, there are two-stage transmission, automatic transmission can only speed the pace to automatically shift, manual transmission can be eliminated, "setback" of the shift feel.Automatic transmission is a torque converter, planetary gears and hydraulic manipulation of bodies, through the hydraulic transmission and gear combination to achieve the purpose of variable-speed torque variation.Also known as CVT-type continuously variable CVT. This transmission and automatic transmission gear generally the biggest difference is that it eliminates the need of complex and cumbersome combination of variable-speed gear transmission, and only two groups to carry out variable-speed drive pulley.CVT transmission than the traditional structure of simple, smaller and it is not the number of manual gear transmission, no automatic transmission planetary gear complex group, mainly rely on the driving wheel, the driven wheel and the transmission ratio brought about by the realization of non-class change.Widely used in automotive internal combustion engine as a power source, the torque and speed range is very small, and complex conditions require the use of motor vehicles and the speed of the driving force in the considerable changes in the scope. To resolve this contradiction, in the transmission system to set up the transmission to change transmission ratio, the expansion of the driving wheel torque and speed range in order to adapt to constantly changing traffic conditions, such as start, acceleration, climbing and so on, while the engine in the most favorable conditions to work under the scope; in the same direction of rotation of the engine under the premise of the automobile can be driven back; the use of neutral, interruption of power transmission, in order to be able to start the engine, idle speed, and ease of transmission or power shift . Transmission is designed to meet the above requirements, so that the conditions in a particular vehicle stability.In addition to transmission can be used to meet certain requirements, but also to ensure that it and the car can have a good match, and can improve the car's power andeconomy to ensure that the engine in a favorable condition to increase the scope of the work of the use of motor vehicles life, reduce energy consumption, reduce noise, such as the use of motor vehicles.Today the world's major car companies CVT are very active in the study. The near future, with electronic control technology to further improve, electronically controlled Continuously Variable Transmission-type is expected to be a wide range of development and application.附录B 文献翻译变速器介绍发动机的输出转速非常高，最大功率及最大扭矩在一定的转速区出现。

变速器设计,中英文带翻译

变速器设计,中英文带翻译

原文：Transmission designAs we all know automobile engine to a certain speed can be achieved under the best conditions, when compared issued by the power, fuel economy is relatively good. Therefore, we hope that the engine is always in the best of conditions to work under. However, the use of motor vehicles need to have different speeds, thus creating a conflict. Transmission through this conflict to resolve.Automotive Transmission role sum up in one sentence, called variable speed twisting, twisting or slow down the growth rate by increasing torsional. Why can slow down by twisting, and the growth rate but also by twisting? For the same engine power output, power can be expressed as N = WT, where w is the angular velocity of rotation. When N fixed, w and T is inversely proportional to the. Therefore, the growth rate will reduce twisting, twisting slowdown will increase. Automotive Transmission speed gear based on the principle of variable twisted into various stalls of different transmission ratio corresponding to adapt to different operational conditions.General to set up a manual gearbox input shaft, intermediate shaft and output shaft, also known as the three-axis, as well as Daodang axis. Three-axis is the main transmission structure, input shaft speed is the speed of the engine, the output shaft speed is the intermediate shaft and output shaft gear meshing between different from the speed. Different gears are different transmission ratio, and will have a different speed. For example Zhengzhou richan ZN6481W2G manual transmission car-SUV, its transmission ratio are: 1 File 3.704:1; stalls 2.202:1; stalls 1.414:1; stalls 1:1 5 stalls (speeding file) 0.802: 1.When drivers choose a launch vehicle stalls, Plectrum will be 1 / 2 file synchronization engagement with a back stall gear and output shaft lock it, the power input shaft, intermediate shaft and output shaft gear of a stall, a stall the output shaft gear driven, and the output shaft power will be transmitted to the drive shaft (red arrow). A typical stall Biansuchilun transmission ratio is 3:1, that is to say three lapsto the input shaft and output shaft to a circle.When the growth rate of car drivers choose two stalls, Plectrum will be 1 / 2-file synchronization and file a joint separation after 2 stall and lock the output shaft gear, power transmission line similar, the difference is that the output shaft gear of a stall 2 stall replaced by the output shaft gear driven. 2 stall Biansuchilun typical transmission ratio is 2.2:1, 2.2 laps to the input shaft and output shaft to a circle than a stall speed increase, lower torque.When refueling vehicle drivers growth stalls option 3, Plectrum to 1 / 2 back to the free file-synchronization position, and also allows the 3 / 4 file synchronization Mobile stall until 3 in the output shaft gear lock, power can be into the shaft axis - intermediate shaft - the output shaft of the three stalls Biansuchilun, led through three stalls Biansuchilun output shaft. 3 stalls typical transmission ratio is 1.7:1, 1.7 laps to the input shaft and output shaft to a circle is further growth.When car drivers Option 4 refueling growth stalls, Plectrum will be 3 / 4 from the 3-file synchronization stall gear directly with the input shaft gear joint initiative, and power transmission directly from the input shaft to the output shaft, the transmission ratio at 1:1, that the input shaft and output shaft speed the same. The driving force without intermediate shaft, also known as direct file, the file transmission than the maximum transmission efficiency. Most cars run-time files are used directly to achieve the best fuel economy.Shift into the first interval when, in a free transmission when Biansuchilun output shaft is not locked in, they cannot rotate the output shaft driven, not power output.General automotive manual transmission than the main 1-4 stalls, usually the first designers to determine the minimum (one stall) and maximum (4 files) transmission ratio, the middle stall drive by geometric progression than the general distribution. In addition, there are stalls Daodang and speeding, speeding file is also known as the five stalls.When the car to accelerate to more than car drivers with the choice of five stalls, and a typical five-transmission ratio is 0.87:1, which is driven by a pinion gear, thegear when the initiative to 0.87 zone, passive gear have been transferred to a circle of the End.Dao Dang, the opposite direction to the output shaft rotation. If one pair of meshing gears when we reverse rotation, with a middle gear, it will become the same to the rotation. Use of this principle, we should add a gear Daodang the "media" will be rotational direction reversed, it will have a Daodang axis. Daodang installed in the transmission shaft independent crust, and the intermediate shaft parallel axis gear with the intermediate shaft and output shaft gear meshing gears, will be contrary to the output shaft.Daodang usually used for the synchronization control also joins five stalls, stalls and Daodang 5 position in the same side. As a middle gear, the general transmission Daodang transmission ratio greater than 1 file transmission ratio, by twisting, steep slope with some vehicles encountered on the progress stalls falters with a Daodang boost.Ride from the driver of the considerations, better transmission stall, stall adjacent stall more than the transmission changes the ratio of small, and easy to shift smoothly. However, the short comings of the stalls is more transmission structure is complicated, bulky, light vehicle transmission is generally 4-5 stalls. At the same time, transmission ratio is not integral, but with all of the decimal point, it is because of the gear teeth meshing is not caused by the whole multiples of two gear teeth can lead to the whole multiples of two meshing gears of uneven wear, making the tooth surface quality have a greater difference.Manual transmission and synchronizerManual transmission is the most common transmission, or MT. Its basic structure sum up in one sentence, is a two-axle shaft, where input shaft, the shaft axis and intermediate shaft, which constitute the main body of the transmission and, of course, a Daodang axis. Manual transmission known as manual gear transmission, which can be in the axial sliding gears, the gears meshing different variable speed reached twisting purpose. Typical manual transmission structure and principles are as follows.Input shaft also said that the first axis, and its front-end spline driven directlywith the clutch disc sets with the spline , by the transfer of torque from the engine. The first axis of the intermediate shaft and gears meshing gears often, as long as the shaft axis to a turn, the intermediate shaft and gear also will be rotating. Vice also said intermediate shaft axis, the axis-even more than the size gear. Also known as the second output shaft axis, the axis of various sets of gear stall progress can be manipulated at any time in the role of the device and the corresponding intermediate shaft gear meshing, thus changing its speed and torque. With the end of the output shaft spline associated with the drive shaft through the drive shaft torque transmitted to the drive axle reducer.Thus, progress stalls drive transmission path is: input shaft gear often rodents - often rodents intermediate shaft gear - corresponding intermediate shaft gear - the second axis corresponding gear. Reversing the gear shaft can be manipulated by the device pick in the axis movement, and the intermediate shaft and output shaft gear meshing gears, to the contrary to the direction of rotation output.Most cars have five stalls and a Daodang forward, a certain degree of each stall transmission ratio, the majority of stalls transmission ratio greater than 1, 4 file transmission ratio of 1, known as direct stalls, and transmission ratio is less than 1 No.5 stall called accelerated stall. Free at the output shaft gear in a position of non-engagement, unacceptable power transmission.The transmission input shaft and output shaft rotational speed to their own, transform a stall when there is a "synchronous". Two different rotational speed gear meshing force will impact the collision occurred, damage gear. Therefore, the old transmission shift to a "feet-off" approach, or stall on the location of the free stay for a while by stalls in the free position refueling doors, in order to reduce the speed differential gear. However, this operation is relatively more complicated and difficult to grasp accurate. So designers create a "synchronized," and allows synchronization through the meshing of gears to be consistent speed and smooth meshing.At present Synchronous Transmission is based on the synchronization of inertia, mainly from joint sets, synchronous lock ring, and so on, it is characterized by friction on the role of synchronization. Splice sets Genlock engagement ring gear and the ringgear when it had Chamfer (Lock angle), Genlock within the cone ring gear engagement with the question of cone ring gear contact friction. Lock and cone angle has been made in the design of an appropriate choice to be made friction cone of the teeth meshing with the ring gear quickly sets pace at the same time will have a Lock role and to prevent the gears meshing in sync before. When synchronization lock cone ring gear engagement with the question of cone ring gear after contact in the effects of friction torque gear speed quickly lower (or higher) with the same speed synchronous lock ring, the two synchronous rotation of the gear Genlock Central zero speed, thus moment of inertia also disappear, then in force under the impetus of engagement sets unhindered and synchronization lock ring gear engagement, and further engagement with the question of gear engagement and the completion Gear Shift Process.The automatic gearboxThe automatic gearbox chooses to block the pole the equal to moving the stick shift of the gearbox, having generally below several blocks:P( parking), R( pour to block), N( get empty to block), D( go forward), S( or2, namely for 2 block soon), L.( or1, namely for 1 block soon)This several an usage for blocking a right usages coming driver the automatic gearbox is automotive of person to say particularly important, underneath let us very much familiar with once automatic gearbox eachly blockings main theme.The usage of the P ( the parking blocks)The launches the luck turns as long as choose to block the pole in driving the position, automatic gearbox car run about very easily.But park, choose to block the pole must pull into of P, from but pass the internal parking system in gearbox moves the device will output the stalk lock lives, combining to tense the hand system move, preventing the car ambulation.The usage of the R( pour to block)R a control for is pouring blocking, using inside wanting slicing recording, automatic gearbox car unlike moving gearbox car so can using half moving, so while reversing the car wanting special attention accelerating pedal.The usage of the N( get empty to block)The N is equal to get empty to block, can while starting or hour of trailer usage.At wait for the signal or block up the car will often often choose to block the pole keeps in the of D, trampling at the same time the next system move.If time is very short, do like this is an admission of, but if stop the time long time had better change into of N, combine to tense the hand system moves.Because choose to block the pole in driving the position, the automatic gearbox car has generally and all to drive the trend faintly, long hours trample the system move same as a deterrent this kind of trend, make gearbox oil gone up, the oil liquid changes in character easily.Particularly in the air condition machine work, launch the soon higher circumstance in machine bottom more disadvantageous.Some pilots for the sake of stanza oil, at made good time or go down slope will choose to block the pole pull the of N skids, this burn the bad gearbox very easily, launching the machine to revolves soon in the however because the gearbox outputs at this time the stalk turns soon very high,, the oil pump provides the oil shortage, lubricating the condition worsen, burn the bad gearbox easily.The usage of the D( go forward to block)Will choose to block when is normal to drive the pole put in the of D, car can at 1 ～4 block( or 3 block) its change to block automatically.The of D drives the position most in common usely. What demand control is: Because the automatic gearbox is soon high and low with car to come to make sure to block according to the accelerator size a, so accelerate the pedal operation method is different, changing to block the hour of the car is soon too not same alike.If start hour quick accelerate the pedal tramples the bottom, rising to block the night, accelerating the ability is strong, arriving certain car soon behind, then will accelerate the pedal loosen to open very quickly, car can rise to block immediately, launch like this the machine voice is small, comfortable good.The another characteristics of the D is a compulsory low blocking, easy to high speed the hour overtakes a car, will accelerate quickly in of D drove the pedal trample after all, connect the compulsory low fend off the pass and then can reduce to block automatically, the car accelerates very quickly, after overtaking a car loosen to openthe pedal of acceleration to can rise to block automatically again.The usage of the S, of L low the usage that blockThe automatic gearbox in in is placed in the low blocking the scope on of S or of Ls, can usage under an etc. circumstance.It change to can make use of to launch well into of S or of Ls the mechanism move, avoiding the car wheel system move the machine over hot, cause the system move the effect descent while going down slope.But change into from the of D of S or of L, car soon can't higher than rise to block the car homologously soon, otherwise strong vibration in opportunity to launch, make gearbox oil hoicked, even will damage the gearbox.The is another at rain fog weather hour, if the road adheres to the term bad, can change into a position for or of L, fixing at somely first lowly blocking driving, doing not use can automatically changing blocking, in order to prevent the car beats slippery.Must keep firmly in mind at the same time, beat the slippery hour can will choose to block the pole pushes into a motive for, cutting off launching machine, toing guarantee a car the safety.汽车变速器设计----------英文文献翻译我们知道，汽车发动机在一定的转速下能够达到最好的状态，此时发出的功率比较大，燃油经济性也比较好。

变速器外文翻译

变速器外文翻译

Continuously Variable Transmissions An Overview of CVT Research Past, Present, and FutureKevin R. Lang21W. 732May 3, 2000Table of Contents Introduction (1)CVT Theory & Design (2)Push Belt (2)Toroidal Traction Drive (2)Variable Diameter Elastomer Belt (3)Other CVT Varieties (3)Background & History (3)Inherent Advantages & Benefits (4)Challenges & Limitations (5)Research & Development (6)New CVT Research (7)Future Prospects for CVTs (9)CVTs & Hybrid Electric Vehicles (9)Conclusion (10)Works Cited (11)Figures and TablesFigure 1 – Metal Push Belt CVT (2)Figure 2 – Toroidal CVT (2)Figure 3 – Variable Diameter Belt CVT (3)Figure 4 – GM’s New CVT Design (6)Figure 5 – Audi CVT with link chain (6)Figure 6 – Cutaway of Audi CVT (7)Table 1 – Efficiency vs. Gear Ratio for Automatic Transmission (4)Table 2 – Efficiency of Various CVT Designs (4)AbstractAs the U.S. government enacts new regulations for automotive fuel economy and emissions, the continuously variable transmission, or CVT, continues to emerge as a key technology for improving the fuel efficiency of automobiles with internal combustion (IC) engines. CVTs use infinitely adjustable drive ratios instead of discrete gears to attain optimal engine performance. Since the engine always runs at the most efficient number of revolutions per minute for a given vehicle speed, CVT-equipped vehicles attain better gas mileage and acceleration than cars with traditional transmissions.CVTs are not new to the automotive world, but their torque capabilities and reliability have been limited in the past. New developments in gear reduction and manufacturing have led to ever-more-robust CVTs, which in turn allows them to be used in more diverse automotive applications. CVTs are also being developed in conjunction with hybrid electric vehicles. As CVT development continues, costs will be reduced further and performance will continue to increase, which in turn makes further development and application of CVT technology desirable.This paper evaluates the current state of CVTs and upcoming research and development, set in the context of past development and problems traditionally associated with CVTs. The underlying theories and mechanisms are also discussed.IntroductionAfter more than a century of research and development, the internal combustion (IC) engine is nearing both perfection and obsolescence: engineers continue to explore the outer limits of IC efficiency and performance, but advancements in fuel economy and emissions have effectively stalled. While many IC vehicles meet Low Emissions Vehicle standards, these will give way to new, stricter government regulations in the very near future. With limited room for improvement, automobile manufacturers have begun full-scale development of alternative power vehicles. Still, manufacturers are loath to scrap a century of development and billions or possibly even trillions of dollars in IC infrastructure, especially for technologies with no history of commercial success. Thus, the ideal interim solution is to further optimize the overall efficiency of IC vehicles.One potential solution to this fuel economy dilemma is the continuously variable transmission (CVT), an old idea that has only recently become a bastion of hope to automakers. CVTs could potentially allow IC vehicles to meet the first wave of new fuel regulations while development of hybrid electric and fuel cell vehicles continues. Rather than selecting one of four or five gears, a CVT constantly changes its gear ratio to optimize engine efficiency with a perfectly smooth torque-speed curve. This improves both gas mileage and acceleration compared to traditional transmissions.The fundamental theory behind CVTs has undeniable potential, but lax fuel regulations and booming sales in recent years have given manufacturers a sense of complacency: if consumers are buying millions of cars with conventional transmissions, why spend billions to develop and manufacture CVTs? Although CVTs have been used in automobiles for decades, limited torque capabilities and questionable reliability have inhibited their growth. Today, however, ongoing CVT research has led to ever-more-robust transmissions, and thus ever-more-diverse automotive applications. As CVT development continues, manufacturing costs will be further reduced and performance will continue to increase, which will in turn increase the demand for further development. This cycle of improvement will ultimately give CVTs a solid foundation in the world’s automotive infrastructure.Figure (1) – Metal Push Belt CVTFrom [3]Figure (2) – Toroidal CVTFrom [3]CVT Theory & DesignToday’s automobiles almost exclusively use either a conventional manual or automatictransmission with “multiple planetary gear sets that use integral clutches and bands to achieve discrete gear ratios” [3]. A typical automatic uses four or five such gears, while a manual normally employs five or six. The continuously variable transmission replaces discrete gear ratios with infinitely adjustable gearing through one of several basic CVT designs.Push BeltThis most common type of CVT usessegmented steel blocks stacked on a steel ribbon, asshown in Figure (1). This belt transmits powerbetween two conical pulleys, or sheaves, one fixedand one movable [3]. With a belt drive:In essence, a sensor reads the engine output and then electronically increases or decreases thedistance between pulleys, and thus the tension of the drive belt. The continuously changing distance between the pulleys—their ratio to one another—is analogous to shifting gears. [6]Push-belt CVTs were first developed decades ago, but new advances in belt design have recently drawn the attention of automakers worldwide.Toroidal Traction-DriveThese transmissions use the high shear strength of viscousfluids to transmit torque between an input torus and an outputtorus. As the movable torus slides linearly, the angle of a rollerchanges relative to shaft position, as seen in Figure (2). Thisresults in a change in gear ratio [3].Variable Diameter Elastomer BeltThis type of CVT, as represented in Figure (2), usesa flat, flexible belt mounted on movable supports. Thesesupports can change radius and thus gear ratio. However,the supports separate at high gear ratios to form adiscontinuous gear path, as seen in Figure (3). This can lead to the problems with creep and slip that have plagued CVTs for years [3]. This inherent flaw has directed research and development toward push belt CVTs.Other CVT VarietiesSeveral other types of CVTs have been developed over the course of automotive history, butthese have become less prominent than push belt and toroidal CVTs. A nutating traction drive uses a pivoting, conical shaft to change “gears” in a CVT. As the cones change angle, the inlet radius decreases while the outlet radius increases, or vice versa, resulting in an infinitely variable gear ratio [3]. A variable geometry CVT uses adjustable planetary gearsets to change gear ratios, but this is more akin to a flexible traditional transmission than a conventional CVT.Background & HistoryTo say that the continuously variable transmission (CVT) is nothing new would be a grossunderstatement: Leonardo da Vinci sketched his idea for a CVT in 1490 [1]. In automotive applications,CVTs have been around nearly as long as cars themselves, and certainly as long as conventionalautomatics. General Motors actually developed a fully toroidal CVT in the early 1930s and conducted extensive testing before eventually deciding to implement a conventional, stepped-gear automatic due to cost concerns. General Motors Research worked on CVTs again in the 1960s, but none ever sawproduction [2]. British manufacturer Austin used a CVT for several years in one of its smaller cars, but “it was dropped due to its high cost, poor reliability, and inadequate torque transmission” [2]. Many early CVTs used a simple rubber band and cone system, like the one developed by Dutch firm Daf in 1958 [1].Figure (3) – Variable Diameter Belt CVTFrom [3]However, the Daf CVT could only handle a 0.6 L engine, and problems with noise and rough starts hurt its reputation [1]. Uninspired by these early failures, automakers have largely avoided CVTs until very recently, especially in the United States.Inherent Advantages & BenefitsCertainly, the clunk of a shifting transmission is familiar to all drivers. By contrast, a continuously variable transmission is perfectly smooth—it naturally changes “gears” discreetly and minutely such that the driver or passenger feels only steady acceleration. In theory, a CVT would cause less engine fatigue and would be a more reliable transmission, as the harshness of shifts and discrete gears force the engine to run at a less-than-optimal speed.Moreover, CVTs offer improved efficiency and performance. Table (1) below shows the power transmission efficiency of a typical five-speed automatic, i.e. the percentage of engine power translated through the transmission. This yields an average efficiency of 86%, compared to a typical manual transmission with 97% efficiency [3]. By comparison, Table (2) below gives efficiency ranges for several CVT designs.Table (1) Efficiency vs. Gear Ratio for Automatic Transmission [3] Gear Efficiency Range160-85%260-90%385-95%490-95%585-94%Table (2) Efficiency of Various CVT Designs [3] CVT Mechanism Efficiency Range Rubber Belts90-95%Steel Belts90-97%Toroidal Traction70-94%Nutating Traction75-96%Variable Geometry85-93%These CVTs each offer improved efficiency over conventional automatic transmissions, and their efficiency depends less on driving habit than manual transmissions [3]. Moreover:Because the CVT allows an engine to run at this most efficient point virtuallyindependent of vehicle speed, a CVT equipped vehicle yields fuel economy benefitswhen compared to a conventional transmission (3)Testing by ZF Getriebe GmbH several years ago found that “the CVT uses at least 10% less fuel than a 4-speed automatic transmission” for U.S. Environmental Protection Agency city and highway cycles. Moreover, the CVT was more than one second faster in 0-60 mph acceleration tests [5]. The potential for fuel efficiency gains can also be seen in the CVT currently used in Honda’s Civic. A Civic with atraditional automatic averages 28/35 miles per gallon (mpg) city/highway, while the same car with a CVT gets 34/38 mpg city/highway [4]. Honda has used continuously variable transmissions in the Civic for several years, but these are 1.6 liter cars with limited torque capabilities. Ongoing research and development will inevitably expand the applicability of CVTs to a much broader range of engines and automobiles.Challenges & LimitationsCVT development has progressed slowly for a variety of reasons, but much of the delay in development can be attributed to a lack of demand: conventional manual and automatic transmissions have long offered sufficient performance and fuel economy. Thus, problems encountered in CVT development usually stopped said progress. “Designers have … unsuccessfully tried to develop [a CVT] that can match the torque capacity, efficiency, size, weight, and manufacturing cost of step-ratio transmissions” [6].One of the major complaints with previous CVTs has been slippage in the drive belt or rollers. This is caused by the lack of discrete gear teeth, which form a rigid mechanical connection between to gears; friction drives are inherently prone to slip, especially at high torque. With early CVTs of the 1950s and 1960s, engines equipped with CVTs would run at excessively high RPM trying to “catch up” to the slipping belt. This would occur any time the vehicle was accelerated from a stop at peak torque:“For compressive belts, in the process of transmitting torque, micro slip occurs betweenthe elements and the pulleys. This micro slip tends to increase sharply once thetransmitted torque exceeds a certain value …” [8]For many years, the simple solution to this problem has been to use CVTs only in cars with relativelylow-torque engines. Another solution is to employ a torque converter (such as those used in conventional automatics), but this reduces the CVT’s efficiency [2].Perhaps more than anything else, CVT development has been hindered by cost. Low volume and a lack of infrastructure have driven up manufacturing costs, which inevitably yield higher transmission prices. With increased development, most of these problems can be addressed simply by improvements in manufacturing techniques and materials processing. For example, Nissan’s Extroid “is derived from aFigure (4) – GM’s New CVT designFrom [6]Figure (5) – Audi CVT with link chainFrom [1]century-old concept, perfected by modern technology, metallurgy, chemistry, electronics, engineering,and precision manufacturing” [2].In addition, CVT control must be addressed. Even if a CVT can operate at the optimal gear ratio at any speed, how does it “know” what ratio to select? Manual transmissions have manual controls,where the driver shifts when he or she so desires; automatic transmissions have relatively simple shifting algorithms to accommodate between three and five gears. However, CVTs require far more complex algorithms to accommodate an infinite division of speeds and gear ratios.Research & DevelopmentWhile IC development has slowed in recent years asautomobile manufacturers devote more resources to hybrid electricvehicles (HEVs) and fuel cell vehicles (FEVs), CVT research anddevelopment is expanding quickly. Even U.S. automakers, who havelagged in CVT research until recently, are unveiling new designs:General Motors plans to implement metal-belt CVTs in some vehiclesby 2002 [6].The Japanese and Germans continue to lead the way in CVT development. Nissan has taken a dramatic step with its “Extroid” CVT, offered in the home-market Cedric and Gloria luxury sedans. This toroidal CVT costs more than a conventional belt-driven CVT, but Nissan expects the extra cost to be absorbed by the luxury cars’ prices [2]. The Extroid uses a high viscosity fluid to transmit power between the disks and rollers, rather than metal-to-metal contact. Coupled with a torque converter, this yields“exceptionally fast ratio changes”. Most importantly, though, theExtroid is available with a turbocharged version of Nissan’s 3.0 literV6 producing 285 lb-ft of torque; this is a new record for CVTtorque capacity [2].Audi’s new CVT offers both better fuel mileage than a conventional automatic and better acceleration than even aFigure (6) – Cutaway of Audi CVT From [1]manual transmission. Moreover, Audi claims it can offer the CVT at only a slight price increase [1]. This so-called “multitronic” CVT uses an all-steel link plate chain instead of a V-belt in order to handle up to 280 lb-ft of torque [1]. In addition, “Audi claims that the multitronic A6accelerates from 0-100 km/h (0-62 mph) 1.3 s quicker than a gearedautomatic transmission and is 0.1 s quicker over the same speed than anequivalent model with “optimum” use of a five speed manual gearbox”[1]. If costs were sufficiently reduced, a transmission such as this couldbe used in almost any automobile in the world.Many small cars have used CVTs in recent years, and many more will use them in the near future. Nissan, Honda, and Subaru currently use belt-drive CVTsdeveloped with Dutch company Van Doorne Transmissie (VDT) in some of their smaller cars [7]. Suzuki and Daihatsu are jointly developing CVTs with Japanese company Aichi Machine, using analuminum/plastic composite belt reinforced with Aramid fibers. Their CVT uses an auxiliary transmission for starts to avoid low-speed slip. After about 6 mph, the CVT engages and operates as it normally would[7]. “The auxiliary geartrain’s direct coupling ensures sufficiently brisk takeoff and initial acceleration”[7]. However, Aichi’s CVT can only handle 52 lb-ft of torque. This alone effectively negates itspotential for the U.S. market. Still, there are far more CVTs in production for 2000 than for 1999, and each major automobile show brings more announcements for new CVTs.New CVT ResearchAs recently as 1997, CVT research focused on the basic issues of drive belt design and power transmission. Now, as belts by VDT and other companies become sufficiently efficient, research focuses primarily on control and implementation of CVTs.Nissan Motor Co. has been a leader in CVT research since the 1970s. A recent study analyzing the slip characteristics of a metal belt CVT resulted in a simulation method for slip limits and torque capabilities of CVTs [8]. This has led to a dramatic improvement in drive belt technology, since CVTs can now be modeled and analyzed with computer simulations, resulting in faster development and moreefficient design. Nissan’s research on the torque limits of belt-drive CVTs has also led to the use of torque converters, which several companies have since implemented. The torque converter is designed to allow “creep,” the slow speed at which automatic transmission cars drive without driver-induced acceleration. The torque converter adds “improved creep capability during idling for improved driveability at very low speeds and easy launch on uphill grades” [9]. Nissan’s Extroid uses such a torque converter for “smooth starting, vibration suppression, and creep characteristics” [2].CVT control has recently come to the forefront of research; even a mechanically perfect CVT is worthless without an intelligent active control algorithm. Optimal CVT performance demands integrated control, such as the system developed by Nissan to “obtain the demanded drive torque with optimum fuel economy” [13]. The control system determines the necessary CVT ratio based on a target torque, vehicle speed, and desired fuel economy. Honda has also developed an integrated control algorithm for its CVTs, considering not only the engine’s thermal efficiency but also work loss from drivetrain accessories and the transmission itself [12]. Testing of Honda’s algorithm with a prototype vehicle resulted in a one percent fuel economy increase compared to a conventional algorithm. While not a dramatic increase, Honda claims that its algorithm is fundamentally sound, and thus will it become “one of the basic technologies for the next generation’s powerplant control” [12].Although CVTs are currently in production, many control issues still amount to a “tremendous number of trials and errors” [10]. One study focusing on numerical representation of power transmission showed that “both block tilting and pulley deformation meaningfully effected the pulley thrust ratio between the driving and the driven pulleys” [10]. Thus, the resultant model of CVT performance can be used in future applications for transmission optimization. As more studies are conducted, fundamental research such as this will become the legacy of CVT design, and research can become more specialized as CVTs become more refined.As CVTs move from research and development to assembly line, manufacturing research becomes more important. CVTs require several crucial, high-tolerance components in order to function efficiently; Honda studied one of these, the pulley piston, in 1998. Honda found that prototype pistons“experienced a drastic thickness reduction (32% at maximum) due to the conventional stretch forming method” [11]. A four-step forming process was developed to ensure “a greater and more uniform thickness increase” and thus greater efficiency and performance. Moreover, work-hardening during the forming process further increased the pulley piston’s strength [11].Size and weight of CVTs has long been a concern, since conventional automatics weigh far more than manual transmissions and CVTs outweigh automatics. Most cars equipped with automatic transmissions have a curb weight between 50 and 150 pounds heavier than the same cars with manual transmissions. To solve this problem, Audi is currently developing magnesium gearbox housings, a first for cars in its class. This results in nearly a 16 pound weight reduction over conventional automatics. [1]. Future Prospects for CVTsMuch of the existing literature is quick to admit that the automotive industry lacks a broad knowledge base regarding CVTs. Whereas conventional transmissions have been continuously refined and improved since the very start of the 20th century, CVT development is only just beginning. As infrastructure is built up along with said knowledge base, CVTs will become ever-more prominent in the automotive landscape. Even today’s CVTs, which represent first-generation designs at best, outperform conventional transmissions. Automakers who fail to develop CVTs now, while the field is still in its infancy, risk being left behind as CVT development and implementation continues its exponential growth. Moreover, CVTs are do not fall exclusively in the realm of IC engines.CVTs & Hybrid Electric VehiclesWhile CVTs will help to prolong the viability of internal combustion engines, CVTs themselves will certainly not fade if and when IC does. Several companies are currently studying implementation of CVTs with HEVs. Nissan recently developed an HEV with “fuel efficiency … more than double that of existing vehicles in the same class of driving performance” [14]. The electric motor avoids the low-speed/high torque problems often associated with CVTs, through an innovative double-motor system. At low speeds:A low-power traction motor is used as a substitute mechanism to accomplish thefunctions of launch and forward/reverse shift. This has made it possible to discontinueuse of a torque converter as the launch element and a planetary gearset and wet multiplateclutches as the shift mechanism. [14]Thus use of a CVT in a HEV is optimal: the electric portion of the power system avoids the low-speed problems of CVTs, while still retaining the fuel efficiency and power transmission benefits at high speeds.. Moreover, “the use of a CVT capable of handling high engine torque allows the system to be applied to more powerful vehicles” [14]. Obviously, automakers cannot develop individual transmissions for each car they sell; rather, a few robust, versatile CVTs must be able to handle a wide range of vehicles.Korean automaker Kia has proposed a rather novel approach to CVTs and their application to hybrids. Kia recently tested a system where “the CVT allows the engine to run at constant speed and the motor allows the engine to run at constant torque independent of driving conditions” [15]. Thus, both gasoline engine and electric motor always run at their optimal speeds, and the CVT adjusts as needed to accelerate the vehicle. Kia also presented a control system for this unified HEV/CVT combination that optimizes fuel efficiency for the new configuration.ConclusionToday, only a handful of cars worldwide make use of CVTs, but the applications and benefits of continuously variable transmissions can only increase based on today’s research and development. As automakers continue to develop CVTs, more and more vehicle lines will begin to use them. As development continues, fuel efficiency and performance benefits will inevitably increase; this will lead to increased sales of CVT-equipped vehicles. Increased sales will prompt further development and implementation, and the cycle will repeat ad infinitum. Moreover, increasing development will foster competition among manufacturers—automakers from Japan, Europe, and the U.S. are already either using or developing CVTs—which will in turn lower manufacturing costs. Any technology with inherent benefits will eventually reach fruition; the CVT has only just begun to blossom.Works Cited[1]S. Birch: “Audi takes CVT from 15th century to 21st century”. Automotive Engineering International,January 2000.[2]J. Yamaguchi: “Nissan’s Extroid CVT”. Automotive Engineering International, February 2000.[3]M.A. Kluger and D.R. Fussner: “An Overview of Current CVT Mechanisms, Forces andEfficiencies” SAE Paper No. 970688, in SAE SP-1241, Transmission and Driveline SystemsSymposium, pp. 81-88 SAE, 1997.[4]U.S. Environmental Protection Agency, /feg/findacar.htm.Accessed 4/15/00.[5]M. Boos and H. Mozer: “ECOTRONIC – The Continuously Variable ZF Transmission (CVT)” SAEPaper No. 970685, in SAE SP-1241, Transmission and Driveline Systems Symposium, pp. 61-67 SAE, 1997.[6]J.L. Broge: “GM Powertrain’s evolving transmissions”. Automotive Engineering International,November 1999.[7]J. Yamaguchi: “Two new CVTs for mini cars”. Automotive Engineering International, March 1999.[8]D. Kobayashi, Y. Mabuchi and Y. Katoh: “A Study on the Torque Capacity of a Metal Pushing V-Belt for CVTs” SAE Paper No. 980822, in SAE SP –1324, Transmission and Driveline Systems Symposium, pp. 31-39 SAE, 1998.[9]K. Abo, M. Kobayashi and M. Kurosawa: “Development of a Metal Belt Drive CVT Incorporating aTorque Converter for Use with 2-liter Class Engines” SAE Paper No. 980823, in SAE SP-1324, Transmission and Driveline Systems Symposium, pp. 41-48 SAE, 1998.[10]T. Miyazawa, T. Fujii, K. Nonaka and M. Takahashi: “Power Transmitting Mechanism of a DryHybrid V-Belt for a CVT – Advanced Numerical Model Considering Block Tilting and PulleyDeformation” SAE Paper No. 1999-01-0751, in SAE SP-1440, Transmission and Driveline Systems Symposium, pp. 143-153 SAE, 1999.[11]K. Ohya and H. Suzuki: “Development of CVT Pulley Piston Featuring Variable Thickness andWork-Hardening Technologies” SAE Paper No. 980826, in SAE SP-1324, Transmission andDriveline Systems Symposium, pp. 71-79 SAE, 1998.[12]S. Sakaguchi, E. Kimura and K. Yamamoto: “Development of an Engine-CVT Integrated ControlSystem” SAE Paper No. 1999-01-0754, in SAE SP-1440, Transmission and Driveline SystemsSymposium, pp. 171-179 SAE, 1999.[13]M. Yasuoka, M. Uchida, S. Katakura and T. Yoshino: “An Integrated Control Algorithm for anSI Engine and a CVT” SAE Paper No. 1999-01-0752, in SAE SP-1440, Transmission and Driveline Systems Symposium, pp. 155-160 SAE, 1999.[14]N. Hattori, S. Aoyama, S. Kitada and I. Matsuo: “Functional Design of a Motor Integrated CVTfor a Parallel HEV” SAE Paper No. 1999-01-0753, in SAE SP-1440, Transmission and Driveline Systems Symposium, pp. 161-167 SAE, 1999.[15] C. Kim, E. NamGoong, S. Lee, T. Kim and H. Kim: “Fuel Economy Optimization for ParallelHybrid Vehicles with CVT” SAE Paper No. 1999-01-1148, in SAE SP-1440, Transmission and Driveline Systems Symposium, pp. 337-343 SAE, 1999.。

自动变速器中英文对照外文翻译文献

自动变速器中英文对照外文翻译文献

中英文对照外文翻译文献(文档含英文原文和中文翻译)How Automatic Transmissions WorkIf you have ever driven a car with an automatic transmission, then you know that there are two big differences between an automatic transmission and a manual transmission:There is no clutch pedal in an automatic transmission car.There is no gear shift in an automatic transmission car. Once you put the transmission into drive, everything else is automatic.Both the automatic transmission (plus its torque converter) and a manual transmission (with its clutch) accomplish exactly the same thing, but they do it in totally different ways. It turns out that the way an automatic transmission does it is absolutely amazing!In this article, we'll work our way through an automatic transmission. We'll start with the key to the whole system: planetary gear sets. Thenwe'll see how the transmission is put together, learn how the controls work and discuss some of the intricacies involved in controlling a transmission.Some BasicsJust like that of a manual transmission, the automatic transmission's primary job is to allow the engine to operate in its narrow range of speeds while providing a wide range of output speeds.Without a transmission, cars would be limited to one gear ratio, and that ratio would have to be selected to allow the car to travel at the desired top speed. If you wanted a top speed of 80 mph, then the gear ratio would be similar to third gear in most manual transmission cars.You've probably never tried driving a manual transmission car using only third gear. If you did, you'd quickly find out that you had almost no acceleration when starting out, and at high speeds, the engine would be screaming along near the red-line. A car like this would wear out very quickly and would be nearly undrive able.So the transmission uses gears to make more effective use of the engine's torque, and to keep the engine operating at an appropriate speed.The key difference between a manual and an automatic transmission is that the manual transmission locks and unlocks different sets of gears to the output shaft to achieve the various gear ratios, while in an automatic transmission, the same set of gears produces all of the different gear ratios. The planetary gear set is the device that makes this possible in an automatic transmission.GearsThis automatic transmission uses a set of gears, called a compound planetary gear set, that looks like a single planetary gear set butactually behaves like two planetary gear sets combined. It has one ring gear that is always the output of the transmission, but it has two sun gears and two sets of planets.Let's look at some of the parts:First GearIn first gear, the smaller sun gear is driven clockwise by the turbine in the torque converter. The planet carrier tries to spin counterclockwise,but is held still by the one-way clutch (which only allows rotation in the clockwise direction) and the ring gear turns the output. The small gear has 30 teeth and the ring gear has 72, so the gear ratio is:Ratio = -R/S = - 72/30 = -2.4:1So the rotation is negative 2.4:1, which means that the output direction would be opposite the input direction. But the output direction is reallythe same as the input direction -- this is where the trick with the twosets of planets comes in. The first set of planets engages the second set, and the second set turns the ring gear; this combination reverses the direction. You can see that this would also cause the bigger sun gear to spin; but because that clutch is released, the bigger sun gear is free to spin in the opposite direction of the turbineSecond GearThis transmission does something really neat in order to get the ratio needed for second gear. It acts like two planetary gear sets connected to each other with a common planet carrier.The first stage of the planet carrier actually uses the larger sun gearas the ring gear. So the first stage consists of the sun (the smaller sun gear), the planet carrier, and the ring (the larger sun gear).The input is the small sun gear; the ring gear (large sun gear) is held stationary by the band, and the output is the planet carrier. so theformula is:1 + R/S = 1 + 36/30 = 2.2:1The planet carrier turns 2.2 times for each rotation of the small sun gear. At the second stage, the planet carrier acts as the input for the second planetary gear set, the larger sun gear (which is held stationary) acts as the sun, and the ring gear acts as the output, so the gear ratio is:1 / (1 + S/R) = 1 / (1 + 36/72) = 0.67:1To get the overall reduction for second gear, we multiply the first stage by the second, 2.2 x 0.67, to get a 1.47:1 reduction. This may sound wacky, but it works.Third GearMost automatic transmissions have a 1:1 ratio in third gear. You'll remember from the previous section that all we have to do to get a 1:1output is lock together any two of the three parts of the planetary gear. With the arrangement in this gear set it is even easier -- all we have todo is engage the clutches that lock each of the sun gears to the turbine.If both sun gears turn in the same direction, the planet gears lockup because they can only spin in opposite directions. This locks the ring gear to the planets and causes everything to spin as a unit, producing a 1:1 ratio. OverdriveBy definition, an overdrive has a faster output speed than input speed.It's a speed increase. In this transmission, engaging the overdrive accomplishes two things at once. If you read How Torque Converters Work,you learned about lockup torque converters. In order to improve efficiency, some cars have a mechanism that locks up the torque converter so that the output of the engine goes straight to the transmission.In this transmission, when overdrive is engaged, a shaft that is attached to the housing of the torque converter (which is bolted to the flywheel of the engine) is connected by clutch to the planet carrier. The small sungear freewheels, and the larger sun gear is held by the overdrive band. Nothing is connected to the turbine; the only input comes from theconverter housing. Let's go back to our chart again, this time with the planet carrier for input, the sun gear fixed and the ring gear for output.Ratio = 1 / (1 + S/R) = 1 / ( 1 + 36/72) = 0.67:1So the output spins once for every two-thirds of a rotation of the engine. If the engine is turning at 2000 rotations per minute (RPM), the outputspeed is 3000 RPM. This allows cars to drive at freeway speed while the engine speed stays nice and slow.ReverseReverse is very similar to first gear, except that instead of the small sun gear being driven by the torque converter turbine, the bigger sun gear is driven, and the small one freewheels in the opposite direction. The planet carrier is held by the reverse band to the housing. So, according to our equations from the last page, we have:Ratio = -R/S = 72/36 = 2.0:1So the ratio in reverse is a little less than first gear in this transmission. Gear RatiosThis transmission has four forward gears and one reverse gear. Let's summarize the gear ratios, inputs and outputs:Gear Input Output FixedGear Ratio1st 30-tooth sun72-toothringPlanetcarrier2.4:12nd30-tooth sunPlanetcarrier36-toothring2.2:1Planetcarrier72-toothring36-toothsun0.67:1Total 2nd 1.47:13rd30- and 36-tooth suns72-toothring1.0:1OD Planet 72-tooth 36-tooth 0.67:1carrier ring sunRever se 36-tooth sun72-toothringPlanetcarrier-2.0:1Hydraulic SystemThe automatic transmission in your car has to do numerous tasks. You may not realize how many different ways it operates. For instance, here are some of the features of an automatic transmission:If the car is in overdrive (on a four-speed transmission), the transmission will automatically select the gear based on vehicle speed and throttle pedal position.If you accelerate gently, shifts will occur at lower speeds than if you accelerate at full throttle.If you floor the gas pedal, the transmission will downshift to the next lower gear.If you move the shift selector to a lower gear, the transmission will downshift unless the car is going too fast for that gear. If the car is going too fast, it will wait until the car slows down and then downshift.If you put the transmission in second gear, it will never downshift or up shift out of second, even from a complete stop, unless you move the shift lever.You've probably seen something that looks like this before. It isreally the brain of the automatic transmission, managing all of these functions and more. The passageways you can see route fluid to all the different components in the transmission. Passageways molded into the metal are an efficient way to route fluid; without them, many hoses would be needed to connect the various parts of the transmission. First, we'll discuss the key components of the hydraulic system; then we'll see how they work together.The PumpAutomatic transmissions have a neat pump, called a gear pump. The pump is usually located in the cover of the transmission. It draws fluid from a sump in the bottom of the transmission and feeds it to the hydraulic system. It also feeds the transmission cooler and the torque converter.The inner gear of the pump hooks up to the housing of the torque converter, so it spins at the same speed as the engine. The outer gear is turned by the inner gear, and as the gears rotate, fluid is drawn up fromthe sump on one side of the crescent and forced out into the hydraulic system on the other side.The GovernorThe governor is a clever valve that tells the transmission how fast thecar is going. It is connected to the output, so the faster the car moves,the faster the governor spins. Inside the governor is a spring-loaded valve that opens in proportion to how fast the governor is spinning -- the faster the governor spins, the more the valve opens. Fluid from the pump is fed to the governor through the output shaft.The faster the car goes, the more the governor valve opens and the higher the pressure of the fluid it lets through.Valves and ModulatorsThrottle Valve or ModulatorTo shift properly, the automatic transmission has to know how hard the engine is working. There are two different ways that this is done. Somecars have a simple cable linkage connected to a throttle valve in the transmission. The further the gas pedal is pressed, the more pressure isput on the throttle valve. Other cars use a vacuum modulator to apply pressure to the throttle valve. The modulator senses the manifold pressure, which drops when the engine is under a greater load.Manual ValveThe manual valve is what the shift lever hooks up to. Depending on which gear is selected, the manual valve feeds hydraulic circuits that inhibitcertain gears. For instance, if the shift lever is in third gear, it feedsa circuit that prevents overdrive from engaging.Shift ValvesShift valves supply hydraulic pressure to the clutches and bands to engage each gear. The valve body of the transmission contains several shift valves. The shift valve determines when to shift from one gear to the next. For instance, the 1 to 2 shift valve determines when to shift from first to second gear. The shift valve is pressurized with fluid from the governor on one side, and the throttle valve on the other. They are supplied with fluid by the pump, and they route that fluid to one of two circuits to control which gear the car runs in.The shift valve will delay a shift if the car is accelerating quickly. If the car accelerates gently, the shift will occur at a lower speed. Let's discuss what happens when the car accelerates gently.As car speed increases, the pressure from the governor builds. Thisforces the shift valve over until the first gear circuit is closed, and the second gear circuit opens. Since the car is accelerating at light throttle, the throttle valve does not apply much pressure against the shift valve.When the car accelerates quickly, the throttle valve applies morepressure against the shift valve. This means that the pressure from the governor has to be higher (and therefore the vehicle speed has to be faster) before the shift valve moves over far enough to engage second gear.Each shift valve responds to a particular pressure range; so when the car is going faster, the 2-to-3 shift valve will take over, because thepressure from the governor is high enough to trigger that valve.Electronic ControlsElectronically controlled transmissions, which appear on some newer cars, still use hydraulics to actuate the clutches and bands, but each hydraulic circuit is controlled by an electric solenoid. This simplifies the plumbing on the transmission and allows for more advanced control schemes.自动变速器如何工作如果你曾经驾驶过一辆带着自动变速器的车, 那么你就知道自动变速器和手动变速器之间有很大的不同:在一个带着自动变速器的汽车中没有离合器踏板。

变速器(英文版文献)

变速器(英文版文献)

Transmission (mechanics)A transmission or gearbox provides speed and torque conversions from a rotating power source to another device using gear ratios. In British English the term transmission refers to the whole drive train, including gearbox, clutch, prop shaft (for rear-wheel drive), differential and final drive shafts. The most common use is in motor vehicles, where the transmission adapts the output of the internal combustion engine to the drive wheels. Such engines need to operate at a relatively high rotational speed, which is inappropriate for starting, stopping, and slower travel. The transmission reduces the higher engine speed to the slower wheel speed, increasing torque in the process. Transmissions are also used on pedal bicycles, fixed machines, and anywhere else rotational speed and torque needs to be adapted.Often, a transmission will have multiple gear ratios (or simply "gears"), with the ability to switch between them as speed varies. This switching may be done manually (by the operator), or automatically. Directional (forward and reverse) control may also be provided. Single-ratio transmissions alsoexist, which simply change the speed and torque (and sometimes direction) of motor output.In motor vehicle applications, the transmission will generally be connected to the crankshaft of the engine. The output of the transmission is transmitted via driveshaft to one or more differentials, which in turn drive the wheels. While a differential may also provide gear reduction, its primary purpose is to change the direction of rotation.Conventional gear/belt transmissions are not the only mechanism for speed/torque adaptation. Alternative mechanisms include torque converters and power transformation (e.g., diesel-electric transmission, hydraulic drive system, etc.). Hybrid configurations also exist.ExplanationEarly transmissions included the right-angle drives and other gearing in windmills, horse-powered devices, and steam engines, in support of pumping, milling, and hoisting.Most modern gearboxes are used to increase torque while reducing the speed of a prime mover output shaft (e.g. a motor crankshaft). This means that the output shaft of a gearbox willrotate at slower rate than the input shaft, and this reduction in speed will produce a mechanical advantage, causing an increase in torque. A gearbox can be setup to do the opposite and provide an increase in shaft speed with a reduction of torque. Some of the simplest gearboxes merely change the physical direction in which power is transmitted.Many typical automobile transmissions include the ability to select one of several different gear ratios. In this case, most of the gear ratios (often simply called "gears") are used to slow down the output speed of the engine and increase torque. However, the highest gears may be "overdrive" types that increase the output speed.UsesGearboxes have found use in a wide variety of different—often stationary—applications, such as wind turbines.Transmissions are also used in agricultural, industrial, construction, mining and automotive equipment. In addition to ordinary transmission equipped with gears, such equipment makes extensive use of the hydrostatic drive and electrical adjustable-speed drives.SimpleThe simplest transmissions, often called gearboxes to reflect their simplicity (although complex systems are also called gearboxes in the vernacular), provide gear reduction (or, more rarely, an increase in speed), sometimes in conjunction with a right-angle change in direction of the shaft (typically in helicopters, see picture). These are often used on PTO-powered agricultural equipment, since the axial PTO shaft is at odds with the usual need for the driven shaft, which is either vertical (as with rotary mowers), or horizontally extending from one side of the implement to another (as with manure spreaders, flail mowers, and forage wagons). More complex equipment, such as silage choppers and snowblowers, have drives with outputs in more than one direction.The gearbox in a wind turbine converts the slow, high-torque rotation of the turbine into much faster rotation of the electrical generator. These are much larger and more complicated than the PTO gearboxes in farm equipment. They weigh several tons and typically contain three stages to achieve an overall gear ratio from 40:1 to over 100:1, depending on the size of the turbine. (For aerodynamic and structuralreasons, larger turbines have to turn more slowly, but the generators all have to rotate at similar speeds of several thousand rpm.) The first stage of the gearbox is usually a planetary gear, for compactness, and to distribute the enormous torque of the turbine over more teeth of the low-speed shaft. Durability of these gearboxes has been a serious problem for a long time.Regardless of where they are used, these simple transmissions all share an important feature: the gear ratio cannot be changed during use. It is fixed at the time the transmission is constructed.For transmission types that overcome this issue, see Continuously Variable Transmission, also known as CVT.Multi-ratio systemsMany applications require the availability of multiple gear ratios. Often, this is to ease the starting and stopping of a mechanical system, though another important need is that of maintaining good fuel efficiency.Automotive basicsThe need for a transmission in an automobile is aconsequence of the characteristics of the internal combustion engine. Engines typically operate over a range of 600 to about 7000 revolutions per minute (though this varies, and is typically less for diesel engines), while the car's wheels rotate between 0 rpm and around 1800 rpm.Furthermore, the engine provides its highest torque outputs approximately in the middle of its range, while often the greatest torque is required when the vehicle is moving from rest or traveling slowly. Therefore, a system that transforms the engine's output so that it can supply high torque at low speeds, but also operate at highway speeds with the motor still operating within its limits, is required. Transmissions perform this transformation.Many transmissions and gears used in automotive and truck applications are contained in a cast iron case, though more frequently aluminium is used for lower weight especially in cars. There are usually three shafts: a mainshaft, a countershaft, and an idler shaft.The mainshaft extends outside the case in both directions: the input shaft towards the engine, and the output shaft towards the rear axle (on rear wheel drive cars- front wheel drives generally have the engine and transmission mountedtransversely, the differential being part of the transmission assembly.) The shaft is suspended by the main bearings, and is split towards the input end. At the point of the split, a pilot bearing holds the shafts together. The gears and clutches ride on the mainshaft, the gears being free to turn relative to the mainshaft except when engaged by the clutches.Types of automobile transmissions include manual, automatic or semi-automatic transmission.ManualMain article: Manual transmissionManual transmission come in two basic types:a simple but rugged sliding-mesh or unsynchronized / non-synchronous system, where straight-cut spur gear sets are spinning freely, and must be synchronized by the operator matching engine revs to road speed, to avoid noisy and damaging "gear clash", and the now common constant-mesh gearboxes which can include non-synchronised, or synchronized / synchromesh systems, where diagonal cut helical (and sometimes double-helical) gear sets are constantly "meshed" together, and a dog clutch is used for changing gears. On synchromesh boxes, friction cones or "synchro-rings" are used in addition to the dog clutch.The former type is commonly found in many forms of racing cars, older heavy-duty trucks, and some agricultural equipment.Manual transmissions are the most common type outside North America and Australia. They are cheaper, lighter, usually give better performance, and fuel efficiency (although the latest sophisticated automatic transmissions may yield results slightly better than the ones yielded by manual transmissions). It is customary for new drivers to learn, and be tested, on a car with a manual gear change. In Malaysia, Denmark and Poland all cars used for testing (and because of that, virtually all those used for instruction as well) have a manual transmission. In Japan, the Philippines, Germany, Italy, Israel, the Netherlands, Belgium, New Zealand, Austria, Bulgaria, the UK, Ireland, Sweden, Estonia, France, Spain, Switzerland, the Australian states of Victoria and Queensland, Finland and Lithuania, a test pass using an automatic car does not entitle the driver to use a manual car on the public road; a test with a manual car is required.Manual transmissions are much more common than automatic transmissions in Asia, Africa, South America and Europe.Most manual transmissions include both synchronized andunsynchronized gearing, such as a reverse gear and a low-speed "granny gear", both of which can only be shifted into when stopped. Shifting from granny gear to a low synchronized gear is generally available while in motion, while shifting out of reverse to any other gear typically requires the vehicle to be stopped.Non-synchronousMain article: Non-synchronous transmissionsThere are commercial applications engineered with designs taking into account that the gear shifting will be done by an experienced operator. They are a manual transmission, but are known as non-synchronized transmissions. Dependent on country of operation, many local, regional, and national laws govern the operation of these types of vehicles (see Commercial Driver's License). This class may include commercial, military, agricultural, or engineering vehicles. Some of these may use combinations of types for multi-purpose functions. An example would be a PTO, or power-take-off gear. The non-synchronous transmission type requires an understanding of gear range, torque, engine power, and multi-functional clutch and shifter functions. Also see Double-clutching, and Clutch-brakesections of the main article at non-synchronous transmissionsAutomaticMain article: Automatic transmissionEpicyclic gearing or planetary gearing as used in an automatic transmission.Most modern North American and Australian and many larger, high specification European and Japanese cars have an automatic transmission that will select an appropriate gear ratio without any operator intervention. They primarily use hydraulics to select gears, depending on pressure exerted by fluid within the transmission assembly. Rather than using a clutch to engage the transmission, a fluid flywheel, or torque converter is placed in between the engine and transmission. It is possible for the driver to control the number of gears in use or select reverse, though precise control of which gear is in use may or may not be possible.Automatic transmissions are easy to use. However, in the past, automatic transmissions of this type have had a number of problems; they were complex and expensive, sometimes had reliability problems (which sometimes caused more expenses in repair), have often been less fuel-efficient than their manualcounterparts (due to "slippage" in the torque converter), and their shift time was slower than a manual making them uncompetitive for racing. With the advancement of modern automatic transmissions this has changed.Attempts to improve the fuel efficiency of automatic transmissions include the use of torque converters which lock up beyond a certain speed, or in the higher gear ratios, eliminating power loss, and overdrive gears which automatically actuate above certain speeds; in older transmissions both technologies could sometimes become intrusive, when conditions are such that they repeatedly cut in and out as speed and such load factors as grade or wind vary slightly. Current computerized transmissions possess very complex programming to both maximize fuel efficiency and eliminate any intrusiveness.For certain applications, the slippage inherent in automatic transmissions can be advantageous; for instance, in drag racing, the automatic transmission allows the car to be stopped with the engine at a high rpm (the "stall speed") to allow for a very quick launch when the brakes are released; in fact, a common modification is to increase the stall speed of the transmission. This is even more advantageous forturbocharged engines, where the turbocharger needs to be kept spinning at high rpm by a large flow of exhaust in order to keep the boost pressure up and eliminate the turbo lag that occurs when the engine is idling and the throttle is suddenly openedSemi-automaticMain article: Semi-automatic transmissionThe creation of computer control also allowed for a sort of cross-breed transmission where the car handles manipulation of the clutch automatically, but the driver can still select the gear manually if desired. This is sometimes called a "clutchless manual," or "automated manual" transmission. Many of these transmissions allow the driver to give full control to the computer. They are generally designed using manual transmission "internals", and when used in passenger cars, have synchromesh operated helical constant mesh gear sets.Specific type of this transmission includes: Easytronic, and Geartronic.A "dual-clutch" transmission uses two sets of internals which are alternately used, each with its own clutch, so that only the clutches are used during the actual "gearchange".Specific type of this transmission includes: Direct-ShiftGearbox.There are also sequential transmissions which use the rotation of a drum to switch gears.Bicycle gearingMain articles: Bicycle gearing, Derailleur gears, and Hub gear Bicycles usually have a system for selecting different gear ratios. There are two main types: derailleur gears and hub gears. The derailleur type is the most common, and the most visible, using sprocket gears. Typically there are several gears available on the rear sprocket assembly, attached to the rear wheel. A few more sprockets are usually added to the front assembly as well. Multiplying the number of sprocket gears in front by the number to the rear gives the number of gear ratios, often called "speeds".Hub gears use epicyclic gearing and are enclosed within the axle of the rear wheel. Because of the small space, they typically offer fewer different speeds, although at least one has reached 14 gear ratios and Fallbrook Technologies manufactures a transmission with technically infinite ratios.Causes for failure of bicycle gearing include: worn teeth, damage caused by a faulty chain, damage due to thermal expansion,broken teeth due to excessive pedaling force, interference by foreign objects, and loss of lubrication due to negligence.Uncommon typesDual clutch transmissionMain article: Dual clutch transmissionThis arrangement is also sometimes known as a direct shift gearbox or powershift gearbox. It seeks to combine the advantages of a conventional manual shift with the qualities of a modern automatic transmission by providing different clutches for odd and even speed selector gears. When changing gear, the engine torque is transferred from one gear to the other continuously, so providing gentle, smooth gear changes without either losing power or jerking the vehicle. Gear selection may be manual, automatic (depending on throttle/speed sensors), or a 'sports' version combining both options.Continuously variableMain article: Continuously variable transmissionThe Continuously Variable Transmission (CVT) is a transmission in which the ratio of the rotational speeds of twoshafts, as the input shaft and output shaft of a vehicle or other machine, can be varied continuously within a given range, providing an infinite number of possible ratios.The continuously variable transmission (CVT) should not be confused with the Infinitely Variable Transmission (IVT) (See below).The other mechanical transmissions described above only allow a few different gear ratios to be selected, but this type of transmission essentially has an infinite number of ratios available within a finite range. The continuously variable transmission allows the relationship between the speed of the engine and the speed of the wheels to be selected within a continuous range. This can provide even better fuel economy if the engine is constantly running at a single speed. The transmission is in theory capable of a better user experience, without the rise and fall in speed of an engine, and the jerk felt when poorly changing gears.Infinitely variableThe IVT is a specific type of CVT that has an infinite range of input/output ratios in addition to its infinite number of possible ratios; this qualification for the IVT implies thatits range of ratios includes a zero output/input ratio that can be continuously approached from a defined 'higher' ratio. A zero output implies an infinite input, which can be continuously approached from a given finite input value with an IVT. [Note: remember that so-called 'low' gears are a reference to low ratios of output/input, which have high input/output ratios that are taken to the extreme with IVT's, resulting in a 'neutral', or non-driving 'low' gear limit.] Most (if not all) IVT's result from the combination of a CVT with an epicyclic gear system (which is also known as a planetary gear system) that facilitates the subtraction of one speed from another speed within the set of input and planetary gear rotations. This subtraction only needs to result in a continuous range of values that includes a zero output; the maximum output/input ratio can be arbitrarily chosen from infinite practical possibilities through selection of extraneous input or output gear, pulley or sprocket sizes without affecting the zero output or the continuity of the whole system. Importantly, the IVT is distinguished as being 'infinite' in its ratio of high gear to low gear within its range; high gear is infinite times higher than low gear. The IVT is always engaged, even during its zero output adjustment.The term 'infinitely variable transmission' does not imply reverse direction, disengagement, automatic operation, or any other quality except ratio selectability within a continuous range of input/output ratios from a defined minimum to an undefined, 'infinite' maximum. This means continuous range from a defined output/input to zero output/input ratio.Electric variableThe Electric Variable Transmission (EVT) is a transmission that achieves CVT action and in addition can use separate power inputs to produce one output. An EVT usually is executed in design with an epicyclic differential gear system (which is also known as a planetary gear system). The epicyclic differential gearing performs a "power-split" function, directly connecting a portion of the mechanical power directly through the transmission and splitting off a portion for subsequent conversion to electrical power via a motor/generator. Hence, the EVT is called a Power Split Transmission (PST) by some.The directly connected portion of the power travelling through the EVT is referred to as the "mechanical path". The remaining power travels down the EVT's "electrical path". Thatpower may be recombined at the output of the transmission or stored for later, more opportune use via a second motor/generator (and energy storage device) connected to the transmission output.The pair of motor/generators forms an Electric Transmission in its own right, but at a lower capacity, than the EVT it is contained within. Generally the Electric Transmission capacity within the EVT is a quarter to a half of the capacity of the EVT. Good reasons to use an EVT instead of an equivalently-sized Electrical transmission is that the mechanical path of the EVT is more compact and efficient than the electrical path.The EVT is the essential method for transmitting power in some hybrid vehicles, enabling an Internal Combustion Engine (ICE) to be used in conjunction with motor/generators for vehicle propulsion, and having the ability to control the portion of the mechanical power used directly for propelling the vehicle and the portion of mechanical power that is converted to electric power and recombined to drive the vehicle.The EVT and power sources are controlled to provide a balance between the power sources that increases vehicle fueleconomy while providing advantageous performance when needed. The EVT may also be used to provide electrically generated power to charge large storage batteries for subsequent electric motor propulsion as needed, or to convert vehicle kinetic energy to electricity through 'regenerative braking' during deceleration. Various configurations of power generation, usage and balance can be implemented with a EVT, enabling great flexibility in propelling hybrid vehicles.The Toyota single mode hybrid and General Motor 2 Mode hybrid are production systems that use EVTs. The Toyota system is in the Prius, Highlander, and Lexus RX400h and GS450h models. The GM system is the Allison Bus hybrid powertrains and are in the Tahoe and Yukon models. The Toyota system uses one power-split epicyclic differential gearing system over all driving conditions and is sized with an electrical path rated at approximately half the capacity of the EVT. The GM system uses two different EVT ranges: one designed for lower speeds with greater mechanical advantage, and one designed for higher speeds, and the electrical path is rated at approximately a quarter of the capacity of the EVT. Other arrangements are possible and applications of EVT's are growing rapidly in number and variety.EVT's are capable of continuously modulating output/input speed ratios like mechanical CVT's, but offer the distinct difference and benefit of being able to also apportion power from two different sources to one output.HydrostaticSee also Continuously variable transmission > Hydrostatic CVTs Hydrostatic transmissions transmit all power hydraulically, using the components of hydraulic machinery. Hydrostatic transmissions do not make use of the hydrodynamic forces of the fluid flow. There is no solid coupling of the input and output. The transmission input drive is a central hydraulic pump and final drive unit(s) is/are a hydraulic motor, or hydraulic cylinder (see:swashplate. Both components can be placed physically far apart on the machine, being connected only by flexible hoses. Hydrostatic drive systems are used on excavators, lawn tractors, forklifts, winch drive systems, heavy lift equipment, agricultural machinery, etc. An arrangement for motor-vehicle transmission was probably used on the Ferguson F-1 P99 racing car in about 1961.The Human Friendly Transmission of the Honda DN-01 is hydrostatic.HydrodynamicIf the hydraulic pump and/or hydraulic motor make use of the hydrodynamic effects of the fluid flow, i.e. pressure due to a change in the fluid's momentum as it flows through vanes in a turbine. The pump and motor usually consist of rotating vanes without seals and are typically placed in close proximity. The transmission ratio can be made to vary by means of additional rotating vanes, an effect similar to varying the pitch of an airplane propeller.The torque converter in most automotive automatic transmissions is, in itself, a hydrodynamic transmission.It was possible to drive the Dynaflow transmission without shifting the mechanical gears.Hydrodynamic transmissions are used in many passenger rail vehicles. In this application the advantage of smooth power delivery may outweigh the reduced efficiency caused by turbulence energy losses in the fluid.ElectricElectric transmissions convert the mechanical power of the engine(s) to electricity with electric generators and convertit back to mechanical power with electric motors. Electrical or electronic adjustable-speed drive control systems are used to control the speed and torque of the motors. If the generators are driven by turbines, such arrangements are called turbo-electric. Likewise installations powered by diesel-engines are called diesel-electric. Diesel-electric arrangements are used on many railway locomotives, ships and large mining trucks.。

汽车变速器的设计外文文献翻译、中英文翻译、外文翻译

汽车变速器的设计外文文献翻译、中英文翻译、外文翻译

汽车变速器的设计外文文献翻译、中英文翻译、外文翻译A manual n。

also known as a standard n。

XXX。

It consistsof gears。

synchros。

roller bearings。

shafts。

and gear selectors。

The main clutch assembly is used to engage and disengage the engine from XXX gears are used to select the desired。

and the sector fork moves gears from one to another using the gearshift knob。

Synchros are used to slow the gear to a。

before it is XXX。

The counter shaft holds the gears in place and against the main input and output shaft。

Unlike automatic ns。

XXX。

as there isno XXX。

Note: XXX "n Shifter" was deleted as it had no XXX.)XXX have four to six forward gears and one reverse gear。

However。

some cars may have up to eight forward gears。

while semi trucks XXX by the number of forward gears。

such as a 5-speed standard n.The n of a standard n includes three shafts: the input shaft。

汽车变速器的设计外文文献翻译、中英文翻译、外文翻译

汽车变速器的设计外文文献翻译、中英文翻译、外文翻译

本科毕业设计（论文）英文资料翻译*****指导教师：孙飞豹（副教授）学科、专业：车辆工程沈阳理工大学应用技术学院2011年12月20日transmission used in automobilesA standard transmission or manual transmission is the traditional type of transmission used in automobiles. The manual or standard transmission consists of a series of gears, synchros, roller bearings, shafts and gear selectors. The main clutch assembly is used to engage and disengage the engine from the transmission. Heliacal cut gears are used to select the ratio desired the sector fork move gears from one to another by using the gearshift knob. Synchros are used to slow the gear to a stop before it is engaged to avoid gear grinding, the counter shaft hold the gears in place and against the main input and output shaft. A stick shift transmission has no torque converter so there is no need for a transmission cooler. A stick shift transmission needs a simple fluid change for proper service. (there is no transmission filter in a stick shift transmission).Transmission ShifterMost manual transmissions have one reverse gear and four to six forward gears. Some cars also have eight forward gears while thirteen to twenty-four gears are present in semi trucks. To differentiate among the available standard transmissions, they are addressed by the number of forward gears. For example, if the standard transmission has five gears, it will be referred to as 5-speed standard transmission or 5-speed standard.Typical Standard Transmission ConfigurationInside the transmission shafts contain all forward and reverse gears. Most transmissions contain three shafts: input shaft, output shaft and counter or lay shaft. Other than standard transmission, there are other transmissions like continuously variable transmission, automatic transmission and semi-automatic transmission. In the manual transmission, a pair of gears inside the transmission selects the gear ratios. Whereas, in an automatic transmission, combination of brake bands and clutch packs control the planetary gear which selects the gear ratio.If there is a provision to select a gear ratio manually in automatic transmissions, the system is called a semi-automatic transmission. The driver can select from any of the gears at any pointof time. In some automobiles like racing cars and motorcycles that have standard transmissions, the driver can select the preceding or the following gear ratio with no clutch operation needed. This type of standard transmission is known as sequential transmission. In this transmission the clutch is still used for initial take off.Clutch and Flywheel AssemblyThe main clutch plays the role of a coupling device which separates the transmission and the engine. If the clutch is absent and the car comes to a stop the engine will stall. In automobiles, the clutch can be operated with the help of a pedal located on the floor of the vehicle. In an automatic transmission instead of a clutch, a torque converter is used to separate the transmission and engine.Typical Stick Shift PatternsA desired gear can be selected by a lever which is usually located on the floor in between the driver and passenger seat. This selector lever is called the gear lever or gear selector or gear shift or shifter. This gear stick can be made to move in right, left, forward and backward direction. When the gear is placed on the N position or neutral position, no gear will be selected. To move the car in the backward direction, the R gear or reverse gear should be selected.Standard transmissions are more efficient and less expensive to produce than automatic transmissions. A Standard transmission is about 15% more efficient compared to an automatic transmission. Standard transmissions are generally stronger than automatic transmissions and off road vehicles take advantage of a direct gear selection so they can withstand rough conditions. Less active cooling is also required in manual transmission system because less power is wasted.●Popular Problem ChecksCar will not go into gearClutch disc is broken completelyInternal transmission damageFailed clutch master cylinderSeized clutch slave cylinderBroken clutch fork pivotBroken clutch cableCar goes into gear but it fades out or is slippingClutch is worn out and needs replacementClutch is oil soaked from a external engine oil leakCar makes grinding noise while operating or shifting gearsOne of the roller or thrust bearings has failedThe gear synchro is worn out not forcing the gear stop before it is engaged causing a grinding gear.A counter or main shaft bearing has failed causing misalignment of the gears●Troubleshooting Noise and ProblemsIf the vehicle is running and a whirring sound is heard, then it goes away when the clutch is depressed, the transmission input bearing has failed.If the transmission is quiet in neutral but when you depress the clutch a squeaking noise is observed, a clutch throw out bearing has failed.Tips:Never let little noises go unattended; a small noise can cause a large noise and transmission operation failure. Never overload a vehicle or tow beyond the capacity this can cause premature transmission failure.汽车变速器汽车传统变速器是那种标准的手动变速器。

汽车变速器变速箱外文文献翻译、中英文翻译、外文翻译

汽车变速器变速箱外文文献翻译、中英文翻译、外文翻译

TRANSMISSIONOf all transmission technologies, the manual gearbox is the most efficient; around 96 per cent of the energy that is put in comes out of the other end. But not everyone can drive one or wants to. Because you have to dip the clutch pedal, it is less comfortable to drive in heavy traffic. It makes the driver tired and the torque interruptions’ head-nod effect on passengers can be wearing.The driver's clutch control and corresponding torque interruptions are also the manuals weak point. When accelerating up through the gearbox, each up-shift requires the driver to cut the torque momentarily by lifting the gas pedal and dipping the clutch. It may just take a second to complete the operation, but during this time the vehicle is losing speed and acceleration.At the opposite end of the spectrum is the traditional automatic. The modern transmission is by far, the most complicated mechanical component in today’s automobile. It is a type of transmission that shifts itself .A fluid coupling or torque converter is used instead of a manually operated clutch to connect the transmission to the engine.There are two basic types of automatic transmissions based on whetherthe vehicle is rear wheel drive . On a rear wheel drive car , the transmission is usually mounted to the back of the engine and is located under the hump in the center of the floorboard alongside the gas pedal position . A drive shaft connects the rear of the transmission to the final drive which is located in the rear axle and is used to send power to the rear wheel. Power flow on this system is simple and straight forward going from the engine, through the torque converter , then through the transmission and driver shaft until it reaches the final driver where it is split and sent to the two rear wheel .On a front wheel drive car, the transmission is usually combined .With the final drive to from what is called a transaxle. The engine on a front wheel driver car is usually mounted sideways in the car with the transaxle tucked under it onthe side of the engine facing the rear of the car. Front axles are connected directly to the transaxle and provide power to the front wheels. In this example, power flows from the engine through the torque converter to a large chain that sends the power through a 180 degree turn to the transmission that is along side the engine. From there，The power is routed through the transmission to the final drive where it is split and sent to the two front wheels through the drive axles.There are a number of other arrangements including front drive vehicles where the engine is mounted front to back instead of sideways and there are other systems that drive all four wheels but the two systems described here are by far the most popular. A must less popular rear drive arrangement has the transmission mounted to the final drive at the rear and is connected by a drive shaft to the torque converter which is still mounted on the engine. This system is found on the new corvette and is used in order to balance the weight evenly between the front and rear wheels for improved performance and handling. Another rear drive system mounts everything, the engine, transmission and final drive in the rear. This rear engine arrangement is popular on the Porsche.The modern automatic transmission consists of many components and systems that are designed to work together in a symphony of planetary gear sets, the hydraulic system, seals and gaskets, the torque converter, the governor and the modulator or throttle cable and computer consider being an art form.On the automobile planet gear mainly uses in two places, one is the driving axle reduction gear, two is the automatic transmission. Very many net friends all want to know that, the planet gear has any function, why automobile must have it . We knew very well the gear major part all rotates the spool thread fixed gear. For example mechanical type clock and watch, above all gears although all in make the rotation, but their rotation center (with center of a circle position superposition) often installs through the bearing on the cabinet, therefore, their rotating axis all is the relative cabinet fixed, thus also is called "dead axle gear" . Has must have surely moves, the corresponding place, some kind of not that manner knows very well is called "planet gear" the gear, their rotation spool thread is not fixed, but is installs the support which may rotate in (blue color) on(in chart black part is shell, yellow expression bearing). The planet gear (green) besides can look like the dead axle gear such to revolve own rotating axis (B-B) to rotate, their rotating axis also (is called planet) along with the blue color support to circle other gears the spool thread (A-A) to rotate. Circles oneself spool thread the rotation to be called "rotation", circles other gear spool threads the rotation to be called "revolution", looks like in solar system planet such, therefore acquires fame.The spool thread fixed gear drive principle is very simple, meshes mutually in a pair in the gear, some gear takes the driving pulley, the power spreads from its there, another gear takes the driven wheel, the power outputs from it toward outside. Also some gears only take the stopover station, at the same time meshes with the driving pulley, one side meshes in addition with the driven wheel, the power passes from its there.In contains the planet gear in the gear system, the situation was different. Because has the planet frame, in other words, may have three rotating axes permissions power input/Output, but also may use the coupling or the brake and so on method. in needs time limits axis the rotation, is left over two axes to carry on the transmission, as the matter stands, meshes mutually between the gear relations may have the many kinds of combinations: The power from sun gear input, outputs from other sun gear, the planet put through brake mechanism has checked dies; Power from sun gear input, from planet output, moreover a sun gear ecks dies; The power from a planet input, outputs from sun gear, moreover a sun gear checks dies; Two powers separately from two sun gears inputs, after synthesis from planet output; Two powers separately from the planet and sun gear input, after the synthesis output from other sun gear; The power from sun gear input, divides two groups outputs from other sun gear and the planet frame; The power from a planet input, divides two groups to output from two sun gears;Its shift quality is good thanks to its torque converter, but efficiency is relatively poor despite recent advances. Because of this, a lot of the current research is trying to find an efficient alternative to the conventional automatic.The main technologies are continuously variable transmissions (CVTs); dualclutch transmissions (DCTs) and automated manual transmission (AMTs).They all offer different benefits over the conventional planetary automatic.The CVT uses a belt chain or torodial shaped dish drive to vary an infinite number of gear ratios. It has improved efficiency and cost when compared to conventional automatics. Its advantage comes from its simplicity. It consists of very few components；usually a rubber or metal-link belt；a hydraulically operated driving pulley, a mechanical torque-sensing driving pulley, microprocessors and some sensors.The transmission works by varying the distance between the face of the two main pulleys. The pulleys have V－shaped grooves in which the connecting the belt rides. One side of the pulley is fixed axially; the other side moves, actuated by hydraulics.When actuated, the cylinder can increase or reduce the amount of space between the two sides of the pulley. This allows the belt to ride lower or higher along the walls of the pulley, depending on driving conditions. This changes the gear ratio. A torodial-type design works in a similar way but runs an discs and power- rollersThe "step less" nature of its design is CVT's biggest draw for automotive engineers .Because of this, a CVT can work to keep the engine in its optimum power range, thereby increasing efficiency and mileage. A CVT can convert every point on the equine’s operating curve to a corresponding point on its own operating curve.The transmission is most popular with Japanese carmakers and Japanese supplier JATCO is a major producer. But in the US and Europe driving styles are different. Uptake has been slow despite Audi and other manufacturers having Offered CVT operations on their ranges.The DCT is, in effect, two manual gearboxes coupled together. Gear shifts are made by switching from one clutch on one gearbox to another clutch on the other. The shift quality is equal to a conventional automatic, but slip, fluid drag and hydraulic losses in the system result in only slightly improved efficienc y and acceleration over the conventional planetary automatic. Developing the controlstrategy is costly too."Resent advances in conventional automatic technology have weakened the argument to develop and set up production for CVT or DCT," says Bill Martin, managing director of transmission firm Zeroshift "Some carmakers have cancelled DCT projects because of the cost."The cheapest way to build an automatic is with an AMT. AMTs use actuators to replace the clutch pedal and gear stick of a conventional manual. They keep the high efficiency and acceleration of a manual gearbox, but the shift quality on some models is lacking. Torque interruptions and the head-nod effect are the most common complaint.SO what is the alternative? There are always new ideas in transmissions, but Zeroshift says that its technology has efficiency benefits over a manual, delivering fuel economy improvements to city driving. Shift quality can also be equal to that of a refined automatic.Zeroshift's approach is an upgrade to the AMT. The synchromesh is replaced with an advanced dog engagement system.Dog engagement has been used for many years in motor sport to allow fast shifts. Conventional dog Boxes are unsuitable for road use as the large spaces between the drive lugs or 'dogs" create backlash, an uncomfortable shunt caused by the sudden change in torque direction.Zeroshift's technology solves this problem by adding a second set of drive dogs. It has also made each of The two sets of dogs only capable of transmitti ng torque in one or other opposing directions错误!未找到引用源。

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In recent years, the automotive automatic transmission there are three main types: mechanical electronic control automatic transmission (AMT), Stepless automatic transmission (CVT) automatic transmission and hydraulic machinery (AT). In the electronically controlled automatic transmission in the field of mechanical, in recent years, there is a newvariable-speed transmission, that is, double-clutch automatic transmission speed (Dual Clutch Transmission), due to both inherited and the AMT structure manual transmission easy to install Compact space, light weight, high-efficiency drive, many of the advantages of low manufacturing costs, and the integration of AT under the uninterrupted power, the rapid shift of the good characteristics of a smooth, quickly became the industry's R & DCT will be the new hot spot for a certain On the degree of change to the existing transmission market. In the next few years, the global transmission of light vehicle market will be AT, CVT, and between the DCT.
Dual-clutch transmission technology development and application of the history of the status quo:
Dual-clutch transmission (DCT) to the concept of the 1960s are now history. As early as1939 inGermanyto apply for the Kegresse.A first dual-clutch gearbox of the patent, a manual transmission will be divided into two parts, the design concept, part of the odd file transfer, even another part of the file transfer. And the transmission of power through the linking of the two clutch two input shaft, adjacent to the file of passive gear and the two staggered mesh gear input shaft, with two clutch control can be achieved without cutting off power conversion of the transmission ratio, thus shortening the Shift time, effectively enhance the quality of transmission,
Dual-clutch transmission characteristics of the structure and working process
The transmission has been carried out in the cargo on board the pilot, was limited to the control of technology, such transmission has not deployed mass production. Then in the 1980s, Porsche is also dedicated to the invention of the car's dual-clutch gearbox (PDK), but it will not DCT technology into mass production.
外文资料翻译
学生姓名：指导教师：朱天军
河北工程大学机电学院
2011年6月
Dual-clutch transmission technology highlights
Transmission technology motor vehicles as a whole is shifting from manual to automatic transmission development, especially at this stage of rapid development of computer technology used in variable-speed transmission system, so that the car automatic transmission technology has been rapid development.
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