汽车离合器课程毕业设计外文文献翻译、中英文翻译、外文翻译

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汽车离合器课程毕业设计外文文献翻译、中英文翻译、外文翻译

CLUTCHThe engine produces the power to drive the vehicle. The drive line or drive train transfers the power of the engine to the wheels. The drive train consists of the parts from the back of the flywh eel to the wheels. These parts include the clutch, th e transmission, the drive shaft, and the final drive assembly (Figure 8-1).The clutch which includes the flywheel, clutch disc, pressure plate, springs, pressure plate cover and the linkage necessary to operate the clutch is a rotating mechanism between t he engine and the transmission (Figure 8-2). It operates through friction which comes from contact between the parts. That is the reason why the clutch is called a friction mechanism. After engagement, the clutch must continue to transmit all the engine torque to the transmission depending on the friction without slippage. The clutch is also used to disengage the engine from the drive train whenever the gears in the transmission are being shifted from one gear ratio to another.To start the engine or shift the gears, the driver has to depress the clutch pedal with the purpose of disengagement the transmission from the engine. At that time, the driven members connected to the transmission input shaft are either stationary or rotating at a speed that is slower or faster than the driving members connected to the engine crankshaft. There is no spring pressure on the clutch assembly parts. So there is no friction between the driving members and driven members. As the driver lets loose the clutch pedal, spring pre ssure increases on the clutch parts. Friction between the parts also increases. The pressure exerted by the springs on the driven members is controlled by the driver through the clutch pedal and linkage. The positive engagement of the driving and driven members is made possible by the friction between the surfaces of the members. When full spring pressure is applied, the speed of the driving and driven members should be the same. At themoment, the clutch must act as a solid coupling device and transmit al l engine power to the transmission, without slipping.However, the transmission should be engaged to the engine gradually in order to operate the car smoothly and minimize torsional shock on the drive train because an engine at idle just develops little power. Otherwise, the driving members are connected with the driven members too quickly and the engine would be stalled.The flywheel is a major part of the clutch. The flywheel mounts to the engine’s crankshaft and transmits engine torque to the clutch assembly. The flywheel, when coupled with the clutch disc and pressure plate makes and breaks the flow of power from the engine to the transmission.The flywheel provides a mounting location for the clutch assembly as well. When the clutch is applied, the flyw heel transfers engine torque to the clutch disc. Because of its weight, the flywheel helps to smooth engine operation. The flywheel also has a large ring gear at its outer edge, which engages with a pinion gear on the starter motor during engine cranking.The clutch disc fits between the flywheel and the pressure plate. The clutch disc has a splined hub that fits over splines on the transmission input shaft. A splined hub has grooves that match splines on the shaft. These splines fit in the grooves. Thus, t he two parts are held together. However, back-and-forth movement of the disc on the shaft is possible. Attached to the input shaft, At disc turns at the speed of the shaft.The clutch pressure plate is generally made of cast iron. It is round and about the same diameter as the clutch disc. One side of the pressure plate is machined smooth. This side will press th e clutch disc facing are against the flywheel. The outer side has various shapes to facilitate attachment of spring and release mechanisms. The two primary types of pressure plate assemblies are coil spri ng assembly and diaphragmspring (Figure 8-3).In a coil spring clutch the pressure plate is backed by a number of coil springs and housed with them in a pressed-steel cover bolted to the flywheel. The springs push against the cover. Neither the driven plate nor the pressure plate is connected rigidly to the flywheel and both can move either towards it or away. When the clutch pedal is depressed a thrust pad riding on a carbon or ball thrust bearing i s forced towards the flywheel. Levers pivoted so that they engage with the thrust pad at one end and the pressure plate at the other end pull the pressure plate back against its springs. This releases pressure on the driven plate disconnecting the gearbox from the engine (Figure 8-4).Diaphragm spring pressure plate assemblies are widely used in most modern cars. The diaphragm spring is a single thin sheet of metal which yields when pressure is applied to it. When pressure is removed the metal springs back to its original shape. The centre portion of the diaphragm spring is slit into numerous fingers that act as release levers. When the clutch assembly rotates with the engine these weights are flung outwards by centrifugal forces and cause the levers to pre ss against the pressure plate. During disengagement of the clutch the fingers are moved forward by the release bearing. The spring pivots over the fulcrum ring and its outer rim moves away from the flywheel. The retracting spring pulls the pressure plate a way from the clutch plate thus disengaging the clutch (Figure 8-5).When engaged the release bearing and the fingers of the diaphragm spring move towards the transmission. As the diaphragm pivots over the pivot ring its outer rim forces the pressure plate against the clutch disc so that the clutch plate is engaged to the flywheel.The advantages of a diaphragm type pres sure plate assembly are its compactness, lower weight, fewer moving parts, less effort to en gage, reduces rotational imbalance by providin g a balanced force around the pressure plate and less chances of clutch slippage.The clutch pedal is connected to the disengagement mechanism either by a cable or, more com monly, by a hydraulic system. Either way, pushing the pedal down operates the dise ngagement mechanism which puts pressure on the fingers of the clutch diaphragm via a release bearing and causes the diaphragm to release the clutch plate. With a hydraulic mechanism, the clutch pedal arm operates a piston in the clutch master cylinder. Thi s forces hydraulic fluid through a pipe to the clutch release cylinder where another piston operates the clutch disengagement mechanism. The alternative is to link the clutch pedal to the disengagement mechanism by a cable.The other parts including the cl utch fork, release bearing, bell-housing, bell housing cover, and pilot bushing are needed to couple and uncouple the transmission. The clutch fork, which connects to the linkage, actually operates the clutch. The release bearing fits between the clutch fork and the pressure plate assembly. The bell housing covers the clutch assembly. The bell housing c over fastens to the bottom of the bell housing. This removable cover allows a mechanic to inspect the clutch without removing the transmission and bell housing. A pilot bushing fits into the back of th e crankshaft and holds the transmission input shaft.Torque ConverterThe BasicsJust like manual transmission cars, cars with automatic transmissions need a way to let the en gine turn while the wheels and gears in the transmission come to a stop. Manual transmission cars use a clutch, which completely disconnects the engine from the transmission. Automatic transmis sion cars use a torque converter.A torque converter is a type of fluid coupling, which allows the engine to spin somewhat independently of the transmission. If the engine is turning slowly, such as when the car is idling at a stoplight,the amount of torque passed through the torque converter is very small, so keeping the car still requires only a li ght pressure on the brake pedal.If you were to step on the gas pedal while the car is stopped, you would have to press harder on the brake to keep the car from moving. This is because when you step on the gas, the engine speeds up and pumps more fluid into the torque converter, causing more torque to be transmitted to the wheels.Inside a Torque ConverterThere are four components inside the very strong housing of the torque converter:1. Pump;2. Turbine;3. Stator;4. Transmission fluid.The housing of the torque converter is bolted to the flywheel of the engine, so it turns at what ever speed the engine is running at. The fins that make up the pump of the torque converter are at tached to the housing, so they also turn at the same speed as the engine. The cutaway below shows how everything is connected inside the torque converter (Figure 8-6).The pump inside a torque converter is a type of centrifugal pump. As it spins, fluid is flung to the outside, much as the spin cycle of a washing machine flings water and clothes to the outside of the wash tub. As fluid is flung to the outside, a vacuum is created that draws more fluid in at the center.The fluid then enters the blades of the turbine, which is connected to the transmission. The turbine causes the transmission to spin, which basically moves the car. The blades of the turbine are curved. This means that the fluid, which enters the turbine from the outside, has to change direction before it exits the center of the turbine. It is this directional change that causes the turbine to spin.The fluid exits the turbine at the center, moving in a different direction than when it entered. The fluid exits the turbine moving opposite the direction that the pump (and engine) is turning. If the fluid were allowed to hit the pump, it would slow the engine down, wasting power. This is why a torque converter has a stator.The stator resides in the very center of the torque converter. Its job is to redirect the fluid returning from the turbine before it hits the pump again. This dramatically increases the efficiency of the torque converter.The stator has a very aggressive blade design that almost completely reverses the direction of the fluid. A one-way clutch (inside the stator) connects the stator to a fixed shaft i n the transmission. Because of this arrangement, the stator cannot spin with the fluid - i tc a n s p i n o n l y i n t h e o p p o s i t ed i re c t i o n,f o r c i ng th e f l ui d t oc h a n g ed i re c t i o n a s i t h i t s t h e s t a t o r b l a d e s.Something a little bit tricky happens when the car gets moving. There is a point, around 40 mph (64 kph), at which both the pump and the turbine are spinning at almost the same speed (the pump always spins slightly faster). At this point, the fluid returns from the turbine, entering the pump already moving in the same direction as the pump, so the stator is not needed.Even though the turbine changes the direction of the fluid and flings it out the back, the fluid still ends up moving in the direction that the turbine is spinning because the turbine is spinning faster in one direction than the fluid is being pumped in the other direction. If you were standing in the back of a pickup moving at 60 mph, and you threw a ball out the back of that pickup at 40 mph, the ball would still be going forward at 20 mph. This is similar to what happens in the tur bine: The fluid is being flung out the back in one direction, but not as fast as it was going to start with in the other direction.At these speeds, the fluid actually strikes the back sides of the stator blades, causing the stator to freewheel on its one-way clutch so it doesn’t hinder the fluid moving through it.Benefits and Weak PointsIn addition to the very important job of allowing a car come to a complete stop without stalling the engine; the torque converter a ctually gives the car more torque when you accelerate out of a Stop. Modern torque converters can multiply the torque of the engine by two to three times. This effect only happens when the engine is turning much faster than the transmission.At higher speeds, the transmission catches up to the engine, eventually moving at almost the same speed. Ideally, though, the transmission would move at exactly the same speed as the engine, because this difference in speed wastes power. This is part of the reason why cars with automatic transmissions get worse gas mileage than cars with manual transmissions.To counter this effect, some cars have a torque converter with a lockup clutch. When the two halves of the torque converter get up to speed, this clutch locks them together, eliminating the slip page and improving efficiency.离合器发动机产生动力用以驱动车辆。

离合器技术发展史外文文献翻译、中英文翻译、外文翻译

Clutch technology development historyIn the 100 years of the history of the development of automobile, almost all of the components in terms of technology development have experienced great changes: reliability, production cost, convenient maintenance, energy saving and emission reduction and so on, have been and will always be the automotive industry in the pursuit of goals, these goals for Automotive engineers continue to develop solutions newer and better.Technically, it was not until 1910 that the reciprocating piston internal combustion engine was significantly more efficient than cars and electric vehicles. In 1902, a gasoline engine car first broke the record of the highest speed, and before that, the highest speed record has been created by steam cars and electric cars. Supporters of the three different drivers of the car have been racing and racing for the first ten years of twentieth Century to break the record.Liquid fuel to drive the car to "steam and electric vehicles" (steam and electric vehicle supporters habit called) has a very prominent advantage is its nearly ideal torque characteristics, they do not need a clutch, does not need the transmission, so it is easy to operate, less failure, easier to maintain. Since the reciprocating piston internal combustion engine can only output torque when it reaches a certain speed, it is necessary to have a separate joint between the engine and the transmission. Gasoline engines need to use the clutch engagement function to start the car, because only when the engine reaches a certain speed, the output torque. In addition to the engagement of the clutch, the clutch's separation function is also important because it is free to move in the vehicle. In view of the complexity of the related problems, there is no clutch engagement function in many small car design structures in the early stage.Origin of clutchThe working principle of first generation clutch from the early use of mechanical equipment factory industrial society. Through the analogy of belt transmission, a kind of flat belt is introduced into the car. By means of the tension of the belt pulley, the belt transfers the output torque of the engine to the driving gear, and when the belt is relaxed by adjusting the roller, the belt slipping is equivalent to the separation of the clutch. Because this process causes the abrasion of the belt is too fast, people will adopt a new method: install a drive pulley with the same size of the idler wheel, by pulling the lever, the drive belt from the idler wheel to drive wheel.This belt drive is a disadvantage, low efficiency, easy to wear, especially the transfer of power shortage in rainy days; on the other hand is the requirement of transmission gear to increase engine torque to constantly improve, this has prompted engineers to explore better to replace the clutch.The result is clutch invented a variety of people, including modern clutch pioneer -- Based on the principle of friction clutch. This is a disc located at the end of the crankshaft and connected to another stationary disk. When the two disks are in contact, the friction is produced, and the stationary disk begins to rotate. With the increase of the clamping force, the driving disc drives the driven disc to make thespeed of the driven disk continuously improve until the transmission is working normally, and the two disks rotate at the same speed. Before the two disks are fully engaged, they are in contact with one side and slip, and most of the kinetic energy from the engine is converted into heat. This structure can meet the following two requirements: on the one hand gently gently engage in when starting a car engine will stall, it will not cause the transmission jitter; on the other hand, the clutch can be nondestructively torque to the transmission.Clutch pedal to work through. Press the clutch pedal, pull the conical seat ring through the separation fork, release the spring, so as to separate the clutch.Early clutchIn 1889, Daimler's steel wheel car had used the basic form of this design principle: equipped with a tapered / bevel friction clutch. The freely movable conical disc is located on the transmission shaft, and the flywheel with a tapered groove on the crankshaft can be firmly engaged. The coil spring presses the conical disc into the tapered groove of the flywheel and the clutch is engaged; the foot pedal can be stepped down, and the conical disc can be pulled back by separating the sleeve and the spring, thereby separating the clutch and interrupting the power transmission. Originally used as a conical disc friction surface material, but was quickly replaced the leather. The latter is soaked in castor oil, can prevent moisture, oil / fat. The utility model has the advantages that the utility model can be automatically adjusted, and the input shaft of the transmission is not stressed. On the one hand, the wear of friction plate is too fast, the replacement is too complex, after the friction in the design of the friction plate spring pin or drive to improve. On the other hand, the flywheel and clutch cone is too large, so that the inertia torque is larger and the clutch is much slower than the required separation process.To solve the above problems, around 1910s, with another clutch brake or brake transmission, it through a second foot pedal to play a role, usually the second pedal and the clutch pedal are connected together, and are located in the rear of the pedal shaft.When changing the speed, many drivers are used to make the clutch slipping and not shift, then the flywheel heating degree is more serious than only by the tapered disc friction cone disc by friction layer of leather to heat. After a long period of long-distance driving, due to the thermal expansion of the flywheel, the cone may be more engaging with the flywheel, but when the flywheel temperature drops, it is difficult to separate the cone from the flywheel.Until the first World War period, metal friction began to spread up. Previously, people also experimented with other different materials, such as NAG company designed a camelhair cone disc thin steel sheet pressing, and fitted with a fanlike blade used for cooling, it engages in the two part, bolted to the flywheel on the leather ring line. The two part of the structure allows the free movement of the leather wire ring, thereby simplifying the clutch maintenance and reducing the number of times the clutch is stuck.Daimler motor company has developed an open friction clutch with an aluminum cone. In order to separate the soft, the oil on the friction layer.Because of the simple structure, the cone disc clutch has been the dominant position in the whole 1920s. Cylindrical friction surfaces are not accepted because of their poor operating performance. Only cylindrical clutch spring clutch with the evolution version, due to its creative design, only by Daimler in late nineteenth Century early twentieth Century with the Mercedes Benz car, and continued until the first world war.The traditional single disc dry clutchIn spring clutch, a wearable spiral spring, and the input shaft of the transmission drum end, mounted in the recess of the flywheel. One end of the spiral spring plate is connected with the flywheel, and the other end is fastened on the spring cover. The clutch pedal presses the spring plate, the leaf spring is more and more tight around the drum shape (automatic enhancement), and drives the transmission input shaft. Only a small force can compress the spring and make the clutch soft.About the development of spring clutch in the Daimler company at the same time, Professor Hele-Shaw from the UK also completed the test of multi disc clutch, which is also considered a precursor to the current traditional single disc dry clutch. One of the key advantages of the "Weston" clutch, which can be produced on a large scale, is that it has a large area of friction and can be continuously engaged in a smaller mounting space.In multi disc clutch, flywheel connected to the drum cover, and according to the outer shape of the coil inside the slot, and allow the disc to rotate with the crankshaft and flywheel, and longitudinal movement. The same number of concave disks are positioned in the center of the hub, and the hub is connected to the clutch shaft. These disks can be moved longitudinally along the clutch shaft on the hub. During the installation, the internal and external driven plates of the clutch are alternately connected to form a set of disks, such as the active and driven disks are always connected with each other.The driven disc work like this: start the bronze plate is always facing the steel wheel, and the spiral spring under the pressure plate is pressed together. In this way, all disks are continuously engaged. The gradual increase in the friction force allows the clutch to engage very softly. With the decrease of the spring pressure, the driven plate is separated, and the supporting part of the driving plate starts to bend from the plane of the driven plate. By changing the number of driven disc pairs, the clutch can be adjusted to fit the output power of each engine.Multi disc clutch for oil / gasoline, can also be dry. The dry type is special, and the friction layer is riveted by rivets. Multi disc clutch, especially the oil bath type multi disc clutch, its biggest drawback is a certain degree of hysteresis, which can only be part of the separation, resulting in difficult shift.After several years, single disc clutch has eliminated the cone disc and multi disc clutch. De Dion and Bouton are the first to realize that a single disc clutch is the future direction of the clutch. With the appearance of Ferodo asbestos friction sheet, clutch technology has made great progress. Asbestos friction sheet has been used since 1920s, until it is replaced by non asbestos friction sheet. The advantage of a single disc dry clutch is obvious: the lower drive disc mass allows it to stop fasterafter separation, thus making it easier to shift gears - a complete farewell to the transmission brake structure.The original structure single disc dry relatively complex. The clutch housing is bolted to the flywheel and the clutch cover is bolted to the clutch housing. The clutch cover with the spring to the inner side of the compression lever is transferred from the intermediate plate through the friction disc, and the torque from the flywheel is transmitted to the transmission. The friction disc is connected to the connection or transmission input shaft by the driver. The clutch is separated and joined by means of a sliding ring plate that allows the tapered disc to move forward and backward. Each side of the cone disc acts on the separating lever correspondingly, and the separating lever is operated by a spiral spring, and is pressed or separated. Due to the fact that the cone is rotating and the sliding ring is stationary, it needs to be lubricated periodically.The spiral spring clutch pressing force provided by the spring, won the people's recognition. At first, the coil spring is placed in the middle of the test, but only a few smaller spiral or spiral spring along the outer ring of the clutch housing arrangement of the structure to be mass production. The release lever compresses the coil spring by a separate bearing which can move freely on the transmission input shaft to separate the clutch. The pressing force can be due to the use of different spring and change, but there is a fatal disadvantage, namely with the increase of engine speed, a spiral spring located in the outer ring of the pressure plate, due to the centrifugal force to the spring cover direction to the outward pressure, the friction between the spring and the cover, the pressing force performance curve change.As the engine speed increases, the clutch becomes heavier and heavier. In addition, the separation bearing used to separate the lever has been in a state of pressure, so that it and the clutch cover is easy to wear, especially in the high speed of the engine gear shift, will soon wear.The birth of diaphragm clutchIn order to solve the problems of these systems, we developed a diaphragm spring clutch diaphragm spring clutch, the research laboratory was born in 1936 of general motors, and mass production in late 1930s in the United states. In Europe, after the Second World War, people began to be familiar with the diaphragm spring clutch through the American General Company military truck, and in the middle of 1950s in a number of single European models. Porsche 356, BMW Goggomobil 700 and DKW Munga is the first batch of the diaphragm spring clutch is equipped with German cars. Diaphragm spring clutch mass production began in 1965 with the Opel Rekord models.Because of the diaphragm spring clutch can be balanced and symmetrical rotation, so it is not affected by the engine speed. The diaphragm spring clutch was a success in 1960s, when the camshaft top mounted high speed engine (Glas, BMW, Alpha Romeo) was widely used to replace the camshaft engine. By the end of the 1960s, almost all car manufacturers have adopted diaphragm spring clutch.Here need to emphasize is: let LuK in diaphragm spring clutch mass production, played a crucial role. Replace all the separate lever helical spring system withdiaphragm spring, brings a lot of advantages: simple structure, constant pressing force, installation space is relatively high pressing force only needs a relatively small (very important for transverse engine) and is not affected by the impact of engine speed. Because of these characteristics, almost all of the modern use of diaphragm spring clutch, and its application in the multi-function car is also more and more - has been the use of spiral spring clutch.With the development of correspondingly, clutch disc has been optimized. Reciprocating piston internal combustion engine changes in the speed and torque generated by the vibration of the crankshaft, clutch, transmission input shaft to the transmission, resulting in noise and severe gear wear. In the modern automobile, the weight of the flywheel and the vehicle is increasing, so the clutch driven disc with the torque damper and the wave spring is developed.Long time operated clutch needs a strong thigh, because the pedal force must be transferred through the connecting rod or shaft / cable. With the application of the clutch and the hydraulic separation mechanism in 1950s in 1930s, the driving comfort has been improved.To try different clutch automatic clutch to make operation more simple: in 1918, Wolseley first proposed the concept of electromagnetic clutch. In the early 1930s, the French Cotal company produced a luxury car with a magnetic clutch, a pre selector transmission. The most famous is the centrifugal clutch to adjust the clamping force by centrifugal force and automatic clutch, such as Saxomat (Fichtel & Sax company), LuKomat (LuK), Manumatik (Borg & Beck) and Ferlec (Ferodo).离合器技术发展史在100多年的汽车发展史中，几乎所有的零部件在技术方面都经历过巨大的发展变化：可靠性、生产成本、维护便利性、节能减排性等，都已经且将一直成为汽车行业的追求目标，这些发展目标要求汽车工程师们不断地开发出更新更好的解决方案。

汽车电子毕设设计外文文献翻译(适用于毕业论文外文翻译+中英文对照)

Ultrasonic ranging system designPublication title: Sensor Review. Bradford: 1993.Vol.ABSTRACT: Ultrasonic ranging technology has wide using worth in many fields, such as the industrial locale, vehicle navigation and sonar engineering. Now it has been used in level measurement, self-guided autonomous vehicles, fieldwork robots automotive navigation, air and underwater target detection, identification, location and so on. So there is an important practicing meaning to learn the ranging theory and ways deeply. To improve the precision of the ultrasonic ranging system in hand, satisfy the request of the engineering personnel for the ranging precision, the bound and the usage, a portable ultrasonic ranging system based on the single chip processor was developed.Keywords: Ultrasound, Ranging System, Single Chip Processor1. IntroductiveWith the development of science and technology, the improvement of people’s standard of living, speeding up the development and construction of the city. Urban drainage system have greatly developed their situation is construction improving. However, due to historical reasons many unpredictable factors in the synthesis of her time, the city drainage system. In particular drainage system often lags behind urban construction. Therefore, there are often good building excavation has been building facilities to upgrade the drainage system phenomenon. It brought to the city sewage, and it is clear to the city sewage and drainage culvert in the sewage treatment system.Co mfort is very important to people’s lives. Mobile robots designed to clear the drainage culvert and the automatic control system Free sewage culvert clear guarantee robots, the robot is designed to clear the culvert sewage to the core. Control system is the core component of the development of ultrasonic range finder. Therefore, it is very important to design a good ultrasonic range finder.2. A principle of ultrasonic distance measurementThe application of AT89C51:SCM is a major piece of computer components are integrated into the chip micro-computer. It is a multi-interface and counting on the micro-controller integration, and intelligence products are widely used in industrial automation. and MCS-51 microcontroller is a typical and representative.Microcontrollers are used in a multitude of commercial applications such as modems, motor-control systems, air conditioner control systems, automotive engine and among others. The high processing speed and enhanced peripheral set of these microcontrollers make them suitable for such high-speed event-based applications. However, these critical application domains also require that these microcontrollers are highly reliable. The high reliability and low market risks can be ensured by a robust testing process and a proper tools environment for the validation of these microcontrollers both at the component and at the system level. Intel Plaform Engineering department developed an object-oriented multi-threaded test environment for the validation of its AT89C51 automotive microcontrollers. The goals of this environment was not only to provide a robust testing environment for the AT89C51 automotive microcontrollers, but to develop an environment which can be easily extended and reused for the validation of several other future microcontrollers. The environment was developed in conjunction with Microsoft Foundation Classes(AT89C51).1.1 Features* Compatible with MCS-51 Products* 2Kbytes of Reprogrammable Flash MemoryEndurance: 1,000Write/Erase Cycles* 2.7V to 6V Operating Range* Fully Static operation: 0Hz to 24MHz* Two-level program memory lock* 128x8-bit internal RAM* 15programmable I/O lines* Two 16-bit timer/counters* Six interrupt sources*Programmable serial UART channel* Direct LED drive output* On-chip analog comparator* Low power idle and power down modes1.2 DescriptionThe AT89C2051 is a low-voltage, high-performance CMOS 8-bit microcomputer with 2Kbytes of flash programmable and erasable read only memory (PEROM). The device is manufactured using Atmel’s high density nonvolatile memory technology and is compatible with the industry standard MCS-51 instruction set and pinout. By combining a versatile 8-bit CPU with flash on a monolithic chip, the Atmel AT89C2051 is a powerful microcomputer which provides a highly flexible and cost effective solution to many embedded control applications.The AT89C2051 provides the following standard features: 2Kbytes of flash,128bytes of RAM, 15 I/O lines, two 16-bit timer/counters, a five vector two-level interrupt architecture, a full duplex serial port, a precision analog comparator, on-chip oscillator and clock circuitry. In addition, the AT89C2051 is designed with static logicfor operation down to zero frequency and supports two software selectable power saving modes. The idle mode stops the CPU while allowing the RAM, timer/counters, serial port and interrupt system to continue functioning. The power down mode saves the RAM contents but freezer the oscillator disabling all other chip functions until the next hardware reset.1.3 Pin Configuration1.4 Pin DescriptionVCC Supply voltage.GND Ground.Prot 1Prot 1 is an 8-bit bidirectional I/O port. Port pins P1.2 to P1.7 provide internal pullups. P1.0 and P1.1 require external pullups. P1.0 and P1.1 also serve as the positive input (AIN0) and the negative input (AIN1), respectively, of the on-chip precision analog comparator. The port 1 output buffers can sink 20mA and can drive LED displays directly. When 1s are written to port 1 pins, they can be used as inputs. When pins P1.2 to P1.7 are used as input and are externally pulled low, they will source current (IIL) because of the internal pullups.Port 3Port 3 pins P3.0 to P3.5, P3.7 are seven bidirectional I/O pins with internal pullups. P3.6 is hard-wired as an input to the output of the on-chip comparator and is not accessible as a general purpose I/O pin. The port 3 output buffers can sink 20mA. When 1s are written to port 3 pins they are pulled high by the internal pullups and can be used as inputs. As inputs, port 3 pins that are externally being pulled low will source current (IIL) because of the pullups.Port 3 also serves the functions of various special features of the AT89C2051 as listed below.1.5 Programming the FlashThe AT89C2051 is shipped with the 2 Kbytes of on-chip PEROM code memory array in the erased state (i.e., contents=FFH) and ready to be programmed. The code memory array is programmed one byte at a time. Once the array is programmed, to re-program any non-blank byte, the entire memory array needs to be erased electrically.Internal address counter: the AT89C2051 contains an internal PEROM address counter which is always reset to 000H on the rising edge of RST and is advanced applying a positive going pulse to pin XTAL1.Programming algorithm: to program the AT89C2051, the following sequence is recommended.1. power-up sequence:Apply power between VCC and GND pins Set RST and XTAL1 to GNDWith all other pins floating , wait for greater than 10 milliseconds2. Set pin RST to ‘H’ set pin P3.2 to ‘H’3. Apply the appropriate combination of ‘H’ or ‘L’ logic to pins P3.3, P3.4, P3.5,P3.7 to select one of the programming operations shown in the PEROM programming modes table.To program and Verify the Array:4. Apply data for code byte at location 000H to P1.0 to P1.7.5.Raise RST to 12V to enable programming.5. Pulse P3.2 once to program a byte in the PEROM array or the lock bits. The byte-write cycle is self-timed and typically takes 1.2ms.6. To verify the programmed data, lower RST from 12V to logic ‘H’ level and set pins P3.3 to P3.7 to the appropriate levels. Output data can be read at the port P1 pins.7. To program a byte at the next address location, pulse XTAL1 pin once to advance the internal address counter. Apply new data to the port P1 pins.8. Repeat steps 5 through 8, changing data and advancing the address counter for the entire 2 Kbytes array or until the end of the object file is reached.9. Power-off sequence: set XTAL1 to ‘L’ set RST to ‘L’Float all other I/O pins Turn VCC power off2.1 The principle of piezoelectric ultrasonic generatorPiezoelectric ultrasonic generator is the use of piezoelectric crystal resonators to work. Ultrasonic generator, the internal structure as shown, it has two piezoelectric chip and a resonance plate. When it’s two plus pulse signal, the frequency equal to the intrinsic piezoelectric oscillation frequency chip, the chip will happen piezoelectric resonance, and promote the development of plate vibration resonance, ultrasound is generated. Conversely, it will be for vibration suppression of piezoelectric chip, the mechanical energy is converted to electrical signals, then it becomes the ultrasonic receiver.The traditional way to determine the moment of the echo’s arrival is based on thresholding the received signal with a fixed reference. The threshold is chosen well above the noise level, whereas the moment of arrival of an echo is defined as the first moment the echo signal surpasses that threshold. The intensity of an echo reflecting from an object strongly depends on the object’s nature, size and distance from the sensor. Further, the time interval from the echo’s starting point to the moment when it surpasses the threshold changes with the intensity of the echo. As a consequence, a considerable error may occur even two echoes with different intensities arriving exactly at the same time will surpass the threshold at different moments. The stronger one will surpass the threshold earlier than the weaker, so it will be considered as belonging to a nearer object.2.2 The principle of ultrasonic distance measurementUltrasonic transmitter in a direction to launch ultrasound, in the moment to launch the beginning of time at the same time, the spread of ultrasound in the air, obstacles on his way to return immediately, the ultrasonic reflected wave received by the receiverimmediately stop the clock. Ultrasound in the air as the propagation velocity of 340m/s, according to the timer records the time t, we can calculate the distance between the launch distance barrier(s), that is: s=340t / 23. Ultrasonic Ranging System for the Second Circuit DesignSystem is characterized by single-chip microcomputer to control the use of ultrasonic transmitter and ultrasonic receiver since the launch from time to time, single-chip selection of 875, economic-to-use, and the chip has 4K of ROM, to facilitate programming.3.1 40 kHz ultrasonic pulse generated with the launchRanging system using the ultrasonic sensor of piezoelectric ceramic sensorsUCM40, its operating voltage of the pulse signal is 40kHz, which by the single-chip implementation of the following procedures to generate.puzel: mov 14h, # 12h; ultrasonic firing continued 200msHere: cpl p1.0; output 40kHz square wavenop;nop;nop;djnz 14h, here;retRanging in front of single-chip termination circuit P1.0 input port, single chip implementation of the above procedure, the P1.0 port in a 40kHz pulse output signal, after amplification transistor T, the drive to launch the first ultrasonic UCM40T, issued 40kHz ultrasonic pulse, and the continued launch of 200ms. Ranging the right and the left side of the circuit, respectively, then input port P1.1 and P1.2, the working principle and circuit in front of the same location.3.2 Reception and processing of ultrasonicUsed to receive the first launch of the first pair UCM40R, the ultrasonic pulse modulation signal into an alternating voltage, the op-amp amplification IC1A and after polarization IC1B to IC2. IC2 is locked loop with audio decoder chip LM567, internal voltage-controlled oscillator center frequency of f0=1/1.1R8C3, capacitor C4 determinetheir target bandwidth. R8-conditioning in the launch of the high jump 8 feet into a low-level, as interrupt request signals to the single-chip processing.Ranging in front of single-chip termination circuit output port INT0 interrupt the highest priority, right or left location of the output circuit with output gate IC3A access INT1 port single-chip, while single-chip P1.3 and P1.4 received input IC3A, interrupted by the process to identify the source of inquiry to deal with, interrupt priority level for the first left right after. Part of the source code is as follows:Receivel: push pswpush accclr ex1; related external interrupt 1jnb p1.1, right; P1.1 pin to 0, ranging from right to interrupt service routine circuitjnb p1.2, left; P1.2 pin to 0, to the left ranging circuit interrupt service routinereturn: SETB EX1; open external interrupt 1pop accpop pswretiright: …; right location entrance circuit interrupt service routineAjmp Returnleft: …; left ranging entrance circuit interrupt service routineAjmp Return3.3 The calculation of ultrasonic propagation timeWhen you start firing at the same time start the single-chip circuitry within the timer T0, the use of timer counting function records the time and the launch of ultrasonic reflected wave received time. When you receive the ultrasonic reflected wave, the receiver circuit output a negative jump in the end of INT0 or INT1 interrupt request generates a signal, single-chip microcomputer in response to external interrupt request, the implementation of the external interrupt service subroutine, read the time difference, calculating the distance. Some of its source code is as follows:RECEIVE0: PUSH PSWPUSH ACCCLR EX0; related external interrupt 0MOV R7, TH0; read the time valueMOV R6, TL0CLR CMOV A, R6SUBB A, #0BBH; calculate the time differenceMOV 31H, A; storage resultsMOV A, R7SUBB A, # 3CHMOV 30H, ASETB EX0; open external interrupt 0\POP ACCPOP PSWRETIFor a flat target, a distance measurement consists of two phases: a coarse measurement and a fine measurement:Step 1: Transmission of one pulse train to produce a simple ultrasonic wave.Step 2: Changing the gain of both echo amplifiers according to equation, until the echo is detected.Step 3: Detection of the amplitudes and zero-crossing times of both echoes.Step 4: Setting the gains of both echo amplifiers to normalize the output at, say 3 volts. Setting the period of the next pulses according to the: period of echoes. Setting the time window according to the data of step 2.Step 5: Sending two pulse trains to produce an interfered wave. Testing the zero-crossing times and amplitudes of the echoes. If phase inversion occurs in the echo, determine to otherwise calculate to by interpolation using the amplitudes near the trough. Derive t sub m1 and t sub m2.Step 6: Calculation of the distance y using equation.4、The ultrasonic ranging system software designSoftware is divided into two parts, the main program and interrupt service routine. Completion of the work of the main program is initialized, each sequence of ultrasonic transmitting and receiving control.Interrupt service routines from time to time to complete three of the rotation direction of ultrasonic launch, the main external interrupt service subroutine to read the value of completion time, distance calculation, the results of the output and so on.5、ConclusionsRequired measuring range of 30cm-200cm objects inside the plane to do a number of measurements found that the maximum error is 0.5cm, and good reproducibility. Single-chip design can be seen on the ultrasonic ranging system has a hardware structure is simple, reliable, small features such as measurement error. Therefore, it can be used not only for mobile robot can be used in other detection system.Thoughts: As for why the receiver do not have the transistor amplifier circuit, because the magnification well, integrated amplifier, but also with automatic gain control level, magnification to 76dB, the center frequency is 38k to 40k, is exactly resonant ultrasonic sensors frequency.6、Parking sensor6.1 Parking sensor introductionReversing radar, full name is "reversing the anti-collision radar, also known as" parking assist device, car parking or reversing the safety of assistive devices, ultrasonic sensors(commonly known as probes), controls and displays (or buzzer)and other components. To inform the driver around the obstacle to the sound or a moreintuitive display to lift the driver parking, reversing and start the vehicle around tovisit the distress caused by, and to help the driver to remove the vision deadends and blurred vision defects and improve driving safety.6.2 Reversing radar detection principleReversing radar, according to high-speed flight of the bats in thenight, not collided with any obstacle principles of design anddevelopment. Probe mounted on the rear bumper, according to different price and brand, the probe only ranging from two, three, four, six, eight,respectively, pipe around. The probe radiation, 45-degree angle up and downabout the search target. The greatest advantage is to explore lower than the bumper of the driver from the rear window is difficult to see obstacles, and the police, suchas flower beds, children playing in the squatting on the car.Display parking sensor installed in the rear view mirror, it constantlyremind drivers to car distance behindthe object distance to the dangerous distance, the buzzer starts singing, allow the driver to stop. When the gear lever linked into reverse gear, reversing radar, auto-start the work, the working range of 0.3 to 2.0 meters, so stop when the driver was very practical. Reversing radar is equivalent to an ultrasound probe for ultrasonic probe can be divided into two categories: First, Electrical, ultrasonic, the second is to use mechanical means to produce ultrasound, in view of the more commonly used piezoelectric ultrasonic generator, it has two power chips and a soundingboard, plus apulse signal when the poles, its frequency equal to the intrinsic oscillation frequency of the piezoelectric pressure chip will be resonant and drivenby the vibration of the sounding board, the mechanical energy into electrical signal, which became the ultrasonic probe works. In order to better study Ultrasonic and use up, people have to design and manufacture of ultrasonic sound, the ultrasonic probe tobe used in the use of car parking sensor. With this principle in a non-contactdetection technology for distance measurement is simple, convenient and rapid, easyto do real-time control, distance accuracy of practical industrial requirements. Parking sensor for ranging send out ultrasonic signal at a givenmoment, and shot in the face of the measured object back to the signal wave, reversing radar receiver to use statistics in the ultrasonic signal from the transmitter to receive echo signals calculate the propagation velocity in the medium, which can calculate the distance of the probe and to detect objects.6.3 Reversing radar functionality and performanceParking sensor can be divided into the LCD distance display, audible alarm, and azimuth directions, voice prompts, automatic probe detection function is complete, reversing radar distance, audible alarm, position-indicating function. A good performance reversing radar, its main properties include: (1) sensitivity, whether theresponse fast enough when there is an obstacle. (2) the existence of blind spots. (3) detection distance range.6.4 Each part of the roleReversing radar has the following effects: (1) ultrasonic sensor: used tolaunch and receive ultrasonic signals, ultrasonic sensors canmeasure distance. (2) host: after the launch of the sine wave pulse to the ultrasonic sensors, and process the received signal, to calculate the distance value, the data and monitor communication. (3) display or abuzzer: the receivinghost from the data, and display the distance value and provide differentlevels according to the distance from the alarm sound.6.5 Cautions1, the installation height: general ground: car before the installation of 45 ~55: 50 ~ 65cmcar after installation. 2, regular cleaningof the probe to prevent the fill. 3, do not use the hardstuff the probe surface cover will produce false positives or ranging allowed toprobe surface coverage, such as mud. 4, winter to avoid freezing. 5, 6 / 8 probe reversing radar before and after the probe is not free to swap may cause the ChangMing false positive problem. 6, note that the probe mounting orientation, in accordance with UP installation upward. 7, the probe is not recommended to install sheetmetal, sheet metal vibration will cause the probe resonance, resulting in false positives.超声测距系统设计原文出处：传感器文摘布拉福德：1993年超声测距技术在工业现场、车辆导航、水声工程等领域具有广泛的应用价值，目前已应用于物位测量、机器人自动导航以及空气中与水下的目标探测、识别、定位等场合。

离合器如何工作外文文献翻译、中英文翻译、外文翻译

附录How Does the Clutch WorkThe clutch is a device to engage and disengage power from the engine, allowing the vehicle to stop and start.A pressure plate or “driving member” is bolted to the engine flywheel, and a clutch plate or “driven member” is loc ated between the flywheel and the pressure plate. The clutch plate is spline to the shaft extending from the transmission to the flywheel, commonly called a clutch shaft or input shaft. When the clutch and pressure plates are locked together by friction, the clutch shaft rotates with the engine crankshaft. Power is transferred from the engine to the transmission, where it is routed through different gear rations to obtain the best speed and power to start and keep the vehicle moving.The flywheel is located at the rear of the engine and is bolted to the crankshaft. It helps absorb power impulses, resulting in a smoothly-idling engine and provides momentum to carry the engine through its operating cycle. The rear surface of the flywheel is machined flat and the clutch components are attached to it. The driving member is commonly called the pressure plate. It is bolted to the engine flywheel and its main purpose is to exert pressure against the clutch plate, holding the plate tight against the flywheel and allowing the power to flow from the engine to the transmission. It must also be capable of interrupting the power flow by releasing the pressure on the clutch plate. This allows the clutch plate to stop rotating while the flywheel and pressure plate continues to rotate.The pressure plate consist of a heavy metal plate, coil springs or diaphragm spring, release levers (fingers), and a cover. When coil springs are used, they are evenly spaced around the metal plate and located between the plate and the metal cover. This places an even pressure against the plate, which in turn presses the clutch plate tight against the flywheel. The cover is bolted tightly to the flywheel and the metal pate is movable, due to internal linkages. The coil springs are arranged to exert direct or indirect tension on the metal plate, depending upon the manufacturer’s design. Three release levers (fingers), evenly spaced around the cover, are used on most pressure plates to release the holding pressure of the springs on the clutch plate, allowing it to disengage the power flow.When a diaphragm spring is used instead of coil springs, the internal linkage is necessarily different to provide an “over-center” action to release the clutch plate from the flywheel. Its operation can be compared to the operation of an oilcan. When depressing the slightly curved metal on the bottom of the oilcan, it goes over-center and gives out a loud “clicking” noise; when released, the noise is again heard as the metal returns to its originalposition. A click is not heard in the clutch operation, but the action of the diaphragm spring is the same as the oilcan.The clutch plate or driven member consists of a round metal plate attached to a splined hub. The outer portion of the round plate is covered with a friction material of molded or woven asbestos and is riveted or bonded to the plate. The thickness of the clutch plate and /or facings may be warped to give a softer clutch engagement. Coil springs are often installed in the hub to help provide a cushion against the twisting force of engagement. The splined hub is mated to (and turns) a splined transmission shaft when the clutch is engaged.The release (throw out) bearing is usually a ball bearing unit, mounted on a sleeve, and attached to the release or throw out lever. Its purpose is to apply pressure to the diaphragm spring or release levers in the pressure plate. When the clutch pedal is depressed, the pressure of the release bearing or lever actuates the internal linkages of the pressure plate, releasing the clutch plate and interrupting the power flow. The release bearing is not in constant contract with the pressure plate. A linkage adjustment clearance should be maintained.The clutch pedal provides mechanical means for the driver to control the engagement and disengagement of the clutch. The pedal is connected mechanically to either a cable or rods, which are directly connected to the release bearing lever.When the clutch pedal is depressed, the linkage moves the release bearing lever. The release lever is attached at the opposite end to a release bearing which straddles the transmission clutch shaft, and presses inward on the pressure plate gingers or the diaphragm spring. This inward pressure acts upon the fingers and internal linkage of the pressure plate and allows the clutch plate to move away from the flywheel, interrupting the flow of power.While the clutch pedal is depressed and the power flow interrupted, the transmission can be shifted in to any gear. The clutch pedal is slowly released to gradually move the clutch pate toward the flywheels under pressure of the pressure plate springs. The friction between the clutch plate and flywheel becomes greater as the pedal is released and the engine speed increased. Once the vehicle is moving, the need for clutch slippage is lessened, and the clutch pedal can be fully released.Coordination between the clutch pedal and accelerator is important to avoid engine stalling, shock to the driveline components and excessive clutch slippage and overheating.离合器如何工作离合器是传递和分离发动机动力的装置，实现车辆的停车和启动。

车辆工程汽车离合器的外文文献翻译

湖北文理学院毕业设计(论文)英文翻译题目有限元热分析的陶瓷离合器专业车辆工程班级Xxx姓名Xxxx学号*******xx指导教师职称Xxx 副教授2014年2月25日Fethermal analysis of a ceramic clutch1. IntroductionAbrasive dry running vehicle clutches are force closure couplings. Torque and speed transmission are ensured by the frictional force generated between two pressed surfaces. Reasons for the application of ceramic as a friction medium include good heat and wear resistance properties, which provide the opportunity to drive higher pressures, and a low density. Thus, an increasing power density is enabled with a parallel minimization of construction space.Measurements with a first prototype of a clutch disk using ceramic facings were performed at Karlsruhe University in a laboratory specialized in passenger car drive system testing. In the course of analysis the finite element (FE) model was to be constructed with the knowledge of measurement data and measurement conditions. Calculations were intended to determine the temperature distribution of the clutch disk and its environment at each moment in time corresponding to measurements. It is essential to be familiar with the temperature range in order to examine the wear characteristics of the system. Thus, important information is derived from measurement data. In critical load cases, the highest expected temperatures must be forecast in space and time in order to protect measuring instruments close to the location of heat generation.The goal of this study is to analyze and modify the clutch system to provide better operating conditions by improving the heat conduction and convection of the system or to increase the amount of the energy converted into frictional heat. Furthermore, it is desired to find better design solutions for more efficient clutch systems.Calculations were performed by the Cosmos Design Star software. During model development, great care had to be taken for proper simplification of geometry, the selection of element sizes, and the correct adjustment of time steps due to the substantial hardware requirements for transient calculations. Changes in thermal parameters such as the surface heat convection coefficient and thermal load had to be taken into consideration on an on-going basis in terms of time and location. The two sides of the analyzed test clutch system can only be managed by two independent models linked by heat partition,according to the hypothesis that the contact temperature must be identical on both sides while there is proper contact between them and its value must be adjusted by iteration. Calculations revealed that the heat partition changed by cycle and it differed along the inner and outer contact rings. As a result of the different cooling characteristics between the ceramic and steel side, a heat ﬂow is launched from the ceramic side to the steel side. This heat flow was also determined by iteration, its value also changes by cycle and differs along the inner and outer contact rings.2. First prototype of a clutch using engineering ceramics as friction materialThe examined clutch disk was developed according to the “specific ceramic” product development process established at the Institute for Product Development (IPEK) at the University of Karlsruhe. This development process already has the possibility for connection to a real transmission shaft; further, it has a cushion spring device for the facings allowing good start behaviour. Abrasive clutches must comply with the following basic requirements:●high torque transmission according to high friction coefficients,●high comfort (no vibrations through self-induced chattering),●homogeneous temperature distribution,●low wear characteristic.A critical element of the switch is the abrasive disk.With regard to the design utmost care must be taken to select the right material. A high and constant friction coefficient,，wear resistance and thermal resistance are desired characteristics. The clutch disk has instead of the generally applied ring-shaped abrasive inlet two rows of SSIC (as sintered) ceramic pellets. These pellets are placed on 6 separate segments. The segments are ﬁxed to the central hub by rivets. Each segment consists of 4 plates, 2 working as facing springs and 2 as carriers.3. MeasurementsMeasurements were performed at the department of power train development of the Institute for Product Development (IPEK) at the Karlsruhe University (TH) ResearchUniversity, where a category IV component test rig is used for tests of new frictional materials and examinations of new materials in real clutch disks. Real conditions are applied by the simulation of driving resistance (e.g. starting in the plane, starting at the hill). It is a component test rig leveled on the fourth position of the tribological testing environment.In order to give an idea of dimensions: the equipment length is about 4-5m. The two electric motors and the axial force are controlled independently by computer; thereby many operational states can be realized. This enables the equipment to complete a myriad of tribological measurements all while properly modeling the operation of a clutch disk in a passenger car. It is also equipped with an automatic IT measurement system. Measurable quantities include the following:●two heavy-duty electric motors (150 KW, Baumuller DS 160L-305),●device suitable for exerting axial force,●torque meter (Manner Sensortelemetrie MF100),●axial force meter,●steel disk in friction,●replaceable head to affix the device to be tested,●temperature along two different radii at 0.4mm below the abrasive surface of the steeldisk (Omega HJMTSS-IM100U-150-2000,J-typeiro-constantan thermocouples),●revolutions per minute for both sides (Polytene LSV 065).The greatest challenge out of these is temperature measurement as we would like to know the temperature of the revolving steel disk. The two thermoelements placed in the steel disk forward data to the computer through a wireless blue tooth system and are placed 0.4mm below the abrasive surface of the steel disk on the two opposite arcs of the clutch disk.3.2. Measurement processDue to component analyses and cost reduction only one side of the clutch disk is mounted with ceramic facings. Thus, the clutch disk and its fitting will be referred to as the ceramic side, and the abrasive steel disk with its environment revolving together will be referred to as the steel side. In the course of measurements, data were collected at a sampling frequency of 100 and 1000HZ. Measurements were conducted according to thetime curves.The measurement starts by increasing the revolutions per minute of the steel side (the driving side) to a specific value (1500 rpm here). Then the ceramic side (the driven side), held at zero rpm, is pushed towards the steel disk and the axial force is applied until a designated value is reached (nominally 4200N here). Upon reaching the designated axial force the ceramic side is released and the two sides start to synchronize. A few seconds after synchronization, the axial load is discontinued and after some time both the steel and the ceramic sides—revolving at the same speed—are slowed down. This is deemed to be one measurement cycle. Ten cycles are completed in the course of a single measurement. During application of the axial force the ceramic side is held at zero rpm until the desired force is reached to ensure synchronization occurs at nearly the same time of each cycle. This is unfavorable from the viewpoint of both measurements and calculations. Measurements are usually conducted by changing only 3 parameters: the speed, the axial load and the inertia. The following figures are applied in various combinations:●speed n: 700, 1100 and 1500 (rpm),●axial force F: 4200, 6400 and 8400 (N) and●inertia I: 1, 1.25 and 1.5 (kgm2).Experimental measurements are launched with approx.10-15 min intervals, during which the system cools down to about 30-40 1C. This makes calculations difficult, as the exact temperature distribution of the system is not known at the commencement of the measurement. However, it can be assumed that a period of 10-15min is sufficient for a nearly homogeneous temperature distribution to be produced. The parameters for the following simulation have been chosen for an intermediate case with a speed n =1500 rpm, an axial force F = 4200 N and an inertia I = 1 kg m2.4. Calculations of heat generationThe mechanical energy consumed during the friction of two bodies is transformed into heat. The generated heat can be calculated by the following simple formula: Q =μ·ν·F [W] .where m is the the frictional coefficient; v is the sliding velocity; F is the force perpendicularly compressing the surfaces. And the heat flux density per surface unit isq=μ·ν·p [Wm2].where p is the the pressure calculated as a ratio of the force and the contacting surface. As the ceramic tablets are placed at two different radii along the clutch disk, the heat generated must be calculated separately for each radii. Sliding can be divided into two sections. In the first section, the ceramic side is kept in a stationary position by braking, meanwhile the axial load is increased; therefore compression changes in the course of time while the speed difference between the two sides is constant. In the second section (at synchronization) the speed difference is equalized while the force value is constant, so velocity changes in time. On the basis thereof, the heat generated is.The nominal contact area is the aggregate of the contacting surfaces of the 24 and 18 ceramic tablets on the given ring. The diameter of ceramic tablets is:.Calculations were performed for the load case to be characterized by the following parameters:.Based on experimental measurements a constant friction coefficient of 0.4 was established..The velocity can be calculated with the knowledge of the radius and the speed..Surface pressure can be calculated as a ratio of the axial force and the contacting surface. This produces the same figure for each ceramic pellet, assuming an even load distribution..Thus, the maximum values of the generated heat are.In the first section of sliding, the generated heat is rising due to the increase of the load force; in the second section, it is decreasing due to the equalization of the speed difference. It is necessary to know the time of each sliding section in order to be able to specify the generated heat time curve. These can be determined from measurement data series. Synchronization time can be easily determined from the speed of the ceramic side. Speed increase is linear. Force increase is non-linear. For the sake of simplicity, force increase was substituted by a straight line in calculations so that the area below the straight line is nearly identical with the area measured below the curve. Thus, the time difference between the two terminal points of the straight line is the time of the first sliding section.The above-mentioned method was applied for each cycle and their average was specified. Based on these results, the following values were determined for sliding times:.Now the time curve of heat generation can be produced. The same curve was used in each cycle as there were no significant differences between parameters in each cycle. The generated heat-calculated this way-will appear as thermal load in the thermal model. It must be distributed appropriately between the contacting surfaces by taking intoconsideration heat partition. Heat partition requires the contact temperatures to be identical at both surfaces. Correct adjustment requires repeated iterations.有限元热分析的陶瓷离合器1 引言磨料空转车辆离合器是力封闭联轴器。

中英文文献翻译-离合器

附录 AClutch between engine and transmission installed in the car to travel from the start the whole process, often need to use the clutch. Its role is to make the engine and transmission can be gradually between the joint, thus ensuring a smooth start car; temporarily cut off the link between the engine and transmission to shift at the time of shift and reduce the impact; When the car when emergency braking from Separate role in preventing the transmission and other drive system overload, play a protective role.Clutch similar to the switch, splice or break away from the power transmission and, accordingly, have any form of auto clutch, but the form is different.By the friction plate clutch, springs, pressure plate and the power output shaft composed, arranged between the engine and gearbox, the engine flywheel to the torque is passed to the stored transmission, to ensure that vehicles in different driving conditions passed to the driver Wheel driving force and the right amount of torque, is the scope of the powertrain. In the half-time of linkage, clutch and power input power output allowed speed difference, that is, the speed error to achieve through its transfer an appropriate amount of power. Clutch is divided into three work status, ie the clutch all connections, some of the half clutch linkage and the clutch is not linked.When a vehicle in normal driving, the pressure plate is jammed against the friction plate on the flywheel, pressure plate and friction plate at this time the friction between the largest between the input shaft and output shaft remained relatively static friction, both the same speed . When the vehicle is started, the driver depresses the clutch, clutch pedal movement by pulling back pressure plate, which is the separation of the pressure plate and friction disc, pressure plate and flywheel at this time no contact, but also the relative friction does not exist. Last one, that is, half of the clutch linkage status. At this point, the pressure plate and friction disc friction less than the full-linked state. Clutch pressure plate and flywheel friction plate on the sliding friction between the state. Flywheel speed is greater than the output shaft speed, transmission out of the power from the flywheel to the transmission part of the pass. Between the engine and driving wheels at this time is equivalent to a soft connection status.In general, the clutch and the shift in the vehicle when starting to play a role, this time a transmission shaft and the speed difference between the two shafts, engine power must be cut with a shaft after the synchronizer can be very good a shaft speed will be kept synchronized with the second axis, gear hanging up after, and then through the clutch shaft and the engine power will be a combination of the power continue to be transmitted. In the clutch, there is an essential buffer device, which consists of two similar to the flywheel with the disc, the disc hit a rectangular groove, the groove arrangement of the spring, in the face of fierce shock between the two disc springs between the elastic effect, buffer external stimuli. Effective protection of the engine and clutch. Various parts of the clutch, pressure plate spring strength, friction coefficient of friction plate, clutch diameter, location, and the clutch friction disc clutch performance is to determine the number of key factors, the greater the stiffness of the spring, the higher the friction coefficient of friction plates, the larger the diameter of the clutch, clutch performance, the better.附录 B离合器安装在发动机与变速器之间，汽车从启动到行驶的整个过程中，经常需要使用离合器。

中英文文献翻译—离合器工作原理

附录How Clutches WorkIf you drive a manual transmission car, you may be surprised to find out that it has more than one clutch. And it turns out that folks with automatic transmission cars have clutches, too. In fact, there are clutches in many things you probably see or use every day: Many cordless drills have a clutch, chain saws have a centrifugal clutch and even some yo-yos have a clutch.CIn!cp I山g?e CgIIeL入D!g?Lg山 o\ cgL 2poM!u? cIn!cp Iocg!!ou. eee 山oLe cIn!cp !山g?e2In this article, you'll learn why you need a clutch, how the clutch in your car works and find out some interesting, and perhaps surprising, places where clutches can be found. Clutches are useful in devices that have two rotating shafts. In these devices, one of the shafts is typically driven by a motor or pulley, and the other shaft drives another device. In a drill, for instance, one shaft is driven by a motor and the other drives a drill chuck. The clutch connects the two shafts so that they can either be locked together and spin at the same speed,or be decoupled and spin at different speeds.In a car,you need a clutch because the engine spins all the time,but the car's wheels do not. In order for a car to stop without killing the engine, the wheels need to be disconnectedf rom the engine somehow. The clutch allows us to smoothly engage a spinning engine to a non-spinning transmission by controlling the slippage between them.To understand how a clutch works, it helps to know a little bit about friction, which is a measure of how hard it is to slide one object over another. Friction is caused by the peaks and valleys that are part of every surface -- even very smooth surfaces still have microscopic peaks and valleys. The larger these peaks and valleys are, the harder it is to slide the object. You can learn more about friction in How Brakes Work.A clutch works because of friction between a clutch plate and a flywheel. We'll look at how these parts work together in the next section.Fly Wheels,Clutch Plates and FrictionIn a car’s clutch, a flywheel connects to the engine, and a clutch plate connects to the transmission. You can see what this looks like in the figure below.When your foot is off the pedal, the springs push the pressure plate against the clutch disc, which in turn presses against the flywheel. This locks the engine to the transmission input shaft, causing them to spin at the same speed.Pressure plateThe amount of force the clutch can hold depends on the friction between the clutch plate and the flywheel, and how much force the spring puts on the pressure plate. The friction force in the clutch works just like the blocks described in the friction section of How Brakes Work, except that the spring presses on the clutch plate instead of weight pressing the block into the ground.W h en the clutch pedal is pressed, a cable or hydraulic piston pushes on the release fork, which presses the throw-out bearing against the middle of the diaphragm spring. As the middle of the diaphragm spring is pushed in, a series of pins near the outside of the spring causes the spring to pull the pressure plate away from the clutch disc (see below). This r eleases the clutch from the spinning engine.Common ProblemsFrom the 1950s to the 1970s, you could count on getting between 50,000 and 70,000 miles from your car's clutch. Clutches can now last for more than 80,000 miles if you use them gently and maintain them well. If not cared for, clutches can start to break down at 35,000 miles. Trucks that are consistently overloaded or that frequently tow heavy loads can also have problems with relatively new clutches.Photo courtesy Carolina MustangClutch plateThe clutch only wears while the clutch disc and the flywheel are spinning at different speeds. When they are locked together, the friction material is held tightly against the flywheel, and they spin in sync. It's only when the clutch disc is slipping against the flywheel that wearing occurs. So, if you are the type of driver who slips the clutch a lot, you'll wear out your clutch a lot faster.Sometimes the problem is not with slipping, but with sticking. If your clutch won't release properly, it will continue to turn the input shaft. This can cause grinding, or completely p revent your car from going into gear. Some common reasons a clutch may stick are: Broken or stretched clutch cable - The cable needs the right amount of tension to push and pull effectively.Leaky or defective slave and/or master clutch cylinders - Leaks keep the cylinders from building the necessary amount of pressure.Air in the hydraulic line - Air affects the hydraulics by taking up space the fluid needs to build pressure.Misadjusted linkage - When your foot hits the pedal, the linkage transmits the wrong amount of force.Mismatched clutch components - Not all aftermarket parts work with your clutch.depress fully. If you have to press hard on the pedal, there may be something wrong. Sticking or binding in the pedal linkage, cable, cross shaft, or pivot ball are common causes. S o metimes a blockage or worn seals in the hydraulic system can also cause a hard clutch. Another problem associated with clutches is a worn throw-out bearing, sometimes called a clutch release bearing. This bearing applies force to the fingers of the spinning pressure plate to release the clutch.If you hear a rumbling sound when the clutch engages,you might have a problem with the throw-out.Types of ClutchesThere are many other types of clutches in your car and in your garage.An automatic transmission contains several clutches. These clutches engage and disengage various sets of planetary gears. Each clutch is put into motion using pressurized hydraulic fluid. When the pressure drops, springs cause the clutch to release. Evenly spacedridges, called splines, line the inside and outside of the clutch to lock into the gears and the clutch housing. You can read more about these clutches in How Automatic Transmissions Work.An air conditioning, compressor in a car has an electromagnetic clutch. This allows the compressor to shut off even while the engine is running. When current flows through a magnetic coil in the clutch, the clutch engages. As soon as the current stops, such as when you turn off your air conditioning, the clutch disengages.Most cars that have an engine-driven cooling fan have a thermostatically controlled viscous clutch -- the temperature of the fluid actually drives the clutch. This clutch is positioned at the hub of the fan, in the airflow coming through the radiator. This type of clutch is a lot like the viscous coupling sometimes found in all-wheel drive cars. The fluid in the clutch gets thicker as it heats up, causing the fan to spin faster to catch up with the engine rotation. When the car is cold, the fluid in the clutch remains cold and the fan spins s lowly, allowing the engine to quickly warm up to its proper operating temperature.Many cars have limited slip differentials or viscous couplings, both of which use clutches to help increase traction. When your car turns, one wheel spins faster than the other, which makes the car hard to handle. The slip differential makes up for that with the help of its clutch. When one wheel spins faster than the others, the clutch engages to slow it down and match the other three. Driving over puddles of water or patches of ice can also spin your wheels. You can learn more about differentials and viscous couplings in How Differentials Work.Gas-powered chain saws and weed eaters have centrifugal clutches, so that the chains or strings can stop spinning without you having to turn off the engine. These clutches work automatically through the use of centrifugal force. The input is connected to the engine crankshaft. The output can drive a chain, belt or shaft. As the rotations per minute increase, w eighted arms swing out and force the clutch to engage. Centrifugal clutches are also often found in lawn mowers, go-karts, mopeds and mini-bikes. Even some yo-yos are m anufactured with centrifugal clutches.C lu tches are valuable and necessary to a number of applications. For more information on clutches and related topics, check out the links on the following page.离合器工作原理如果您驾驶手动变速箱的汽车，您可能会惊讶地发现，它有一个以上的离合器。

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。

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