折弯机液压系统的设计解读

折弯机液压系统的设计

折弯机机属于一种锻造机械。它是一个主要角色在金属加工行业。产品广泛应用于 :轻工、航空、船舶、冶金、仪表、电器、不锈钢制品、钢结构建筑和装饰行业。

液压系统采用活塞泵的压力补偿提供油、回油节流控制 , 合理使用能源。垂直液压缸使用平衡和锁定措施 , 所以 safly 和在国内工作。同时液压缸组件的实现有伟大的夹紧力和剪切力。当系统剪切板材料 , 它的性能很好

新闻系统的设计 , 金属板剪切系统和液压泵站系统的电路设计和泵站的结构、布局和一些非标准组件的设计。在设计过程中 , 实现了结构紧凑、布局合理、制造简单。

液压系统的概况

安妮媒体 (液体或气体 , 自然流动或可以被迫流可以用来传递能量的流体动力系统。使用最早的流体是水因此得名液压应用于系统使用液体。在现代术语 , 液压意味着电路使用矿物油。图 1 - 1显示了一个基本的液压系统的动力装置。 (注意 , 水是有了复苏迹象的末 90年代 ; 一些流体动力系统今天海水甚至操作。其他常见的流体在流体动力电路是压缩空气。如图 1 - 2所示 , 大气——压缩 7 - 10倍——是现成的和流动很容易通过管道 , 管道或软管传送能量来工作。其他气体 , 如氮或氩 , 可以使用但昂贵的生产和过程。

权力是最难理解的行业。在大多数植物很少有直接责任人员流体动力电路设计或维护。通常 , 一般力学保持流体动力电路 fluid-power-distributor 最初设计的销售人员。在大多数设施 , 负责流体动力系统是机械工程师的工作描述的一部分。问题是 , 机械工程师通常在大学接受

小如果任何流体动力的培训 , 所以他们会疲于执行这个任务。适度的流体动力培训和足够多的处理工作 , 工程师往往取决于流体动力分配器的专业知识。订单 , 经销商销售人员很高兴设计电路 , 经常协助安装和启动。这种安排相当有效 , 但与

其他技术的进步 , 许多机器上流体动力被拒绝的功能。总是倾向于使用最理解那些涉及的设备。

流体动力缸和马达是紧凑和高能源的潜力。他们适合在小空间而不杂乱。这些设备可以长时间停滞不前 , 立即可逆的 , 有无限变速 , 常常取代机械联系以低得多的成本。具有良好的电路设计 , 电源 , 阀门和执行器将运行维护延长时间。的主要缺点是缺乏了解设备和电路设计不佳 , 这会导致过热和泄漏。机器过热时比动力单元提供消耗更少的能源。 (过热通常很容易设计的电路。控制泄漏是一种使用straight-thread o形环配件或油管连接软管和 SAE 法兰管尺寸较大的配件。设计电路的最小冲击和很酷的操作也会降低泄漏。

通常在选择使用液压或气动缸是 :如果指定的力量需要一个气缸孔 4或 5。或更大 , 选择液压。大多数气动回路都面临 3惠普因为空气压缩的效率很低。液压系统 , 需要 10个惠普将用大约 30到 50马力气压缩机。空气回路不太昂贵的建造 , 因为不需要一个单独的原动力 , 但运营成本更高 , 可以迅速抵消低组件费用。 20-in 情况。生气缸可以经济如果它只骑一天几次还是用来保存紧张和没有骑车。空气和液压回路的操作在危险区域使用空气或防爆电气控制逻辑控制。与某些预防措施、气缸和电机的类型可以在高湿大气。甚至在水中。

当使用流体动力在食物和医疗用品 , 最好是管外的空气排出清洁区域和使用液压回路欢的流体。

某些应用程序需要液体的刚度 , 似乎在眼下这种情况下需要使用液压即使低功率需求。对于这些系统 , 结合使用的空气

电源和石油作为工作流体削减成本和准确停止还有 lunge-free 控制选项和持有。 Air-oil 槽系统、串联油缸系统 , 气缸与整体控制 , 和加强词有几个可用的组件。

液体可以传递能量的原因包含从 17世纪最好的说明是一个男人叫布莱斯帕斯卡尔。帕斯卡定律是流体动力的基本法律之一。本法说 :压力在一个封闭的流体行

为同样四面八方和包含表面成直角。说这的另一种方法是 :如果我在压力容器或戳一个洞 , 我将 PSO 。 PSO 代表压力喷射出来 , 刺穿加压液相线会让你湿了。图 1 - 3显示了本法在气缸工作应用程序。从油泵流入气缸 , 升降负荷。负载的电阻会造成气缸内压力建立 , 直到负载开始移动。在负荷运动 , 压力在整个电路保持几乎不变。加压油正试图摆脱泵、管、汽缸 , 但这些机制是强大到足以包含流体。当压力对活塞面积变得高到足以克服负载电阻 , 石油部队负载向上移动。理解帕斯卡定律很容易看出所有的液压和气动回路功能。

注意在这个例子中两个重要的事情。首先 , 泵并没有使压力 ; 它只生产流。泵不会让压力。他们只给流。泵流动阻力造成的压力。这是流体动力的基本原则之一 , 对故障至关重要液压回路。假设一个机泵运行显示几乎 0 psi压力表。这是否意味着水泵是坏的吗 ? 没有在泵出口流量计 , 力学可能改变泵 , 因为他们中的许多人认为泵的压力。这种电路的问题可能仅仅是一个开启阀门 , 允许所有泵直接流向。因为泵出口流量认为没有抵抗 , 压力表显示很少或没有压力。流量计安装 , 这将是显而易见的泵都是正确的坦克和其他原因 , 如开放路径必须被发现和纠正。

另一个显示帕斯卡定律的影响是一个比较液压和机械杠杆。图 1 - 4显示了这两个系统是如何工作的。在这两种情况下 , 大部队抵消了更小的力是由于活塞杆臂长度或面积的差异。注意液压杠杆并不局限于一定距离 , 高度 , 或物理位置如机械杠杆。这是一个许多机制决定的优势 , 因为大多数设计使用流体动力更少的空间 , 不受位置考虑。缸 , 扶轮致动器 , 或流体与几乎无限的力或力矩电动机可以直接推动或旋转机器成员。这些操作只需要流线条的致动器和反馈设备显示的位置。连接驱动的主要优势是精密定位和控制没有反馈的能力。

第一眼看上去 , 它可能会出现机械或液压杠杆能够节约能源。例

如 :40000磅是一个 10000磅如图 1 - 4所示。然而 , 请注意 , 杠杆臂的比值和活塞是 4:1。这意味着通过添加额外的力量说到 10000磅 , 它会降低和 40000磅上升。当 10000 - 10磅体重向下移动的距离。 ,40000磅的体重只有 2.5。

工作是衡量一个力的遍历。 (工作 =力 ×距离。工作通常是在 foot-pounds 表

示 , 作为州的公式 , 它是力量的产物在英尺磅倍距离。当一个汽缸举起 20000磅加载一个 10英尺的距离 , 气缸执行 200000英尺 -磅的工作。这个动作可能发生在三秒内 , 三分钟 , 三个小时不改变的工作量。当工作在一定的时间内完成 , 它被称为权力。 {功率 =(力和距离 X/时间。 }的常见措施权力是马力——一个术语取自早期当大多数人可能与一匹马的力量。这使得一般人评估新权力的手段 , 如蒸汽机。权力是做功的速率。一马力被定义为体重的磅 (力量一匹可以抬起一只脚 (距离在一秒 (时间。对于普通的马这是 550磅。一只脚在一秒钟。改变时间 60秒 (一分钟 , 它通常表示为每分钟 33000英尺 -磅。

不需要考虑压缩系数在大多数液压回路 , 因为石油只能压缩少量。通常情况下 , 液体被认为是

不可压缩 , 但几乎所有液压系统有空气被困在其中。气泡太小甚至视力好的人不能看见它们 , 但是这些泡沫允许大约 0.5%每 1000 psi的压缩性。应用程序 , 这少量的压缩性有一个负面影响包括 :single-stroke air-oil

含硼铁合金 ; 系统运行非常高循环率 ; 伺服系统 , 保持 closetolerance 定位或压力 ; 电路包含大量的液体。在这本书中 , 当显示电路压缩是一个因素 , 它将指出随着减少或允许它的方式。

另一个情况 , 使它看起来有压缩性比前所述如果管道 , 软管 , 加压时 , 气缸管扩大。这个需要更多的流体体积来构建和执行所需的工作压力。此外 , 当气缸推一个负载 , 机器成员抵制这个力可能延伸 , 又需要更多的流体进入气缸前能完成循环。

任何人都知道 , 气体可压缩。一些应用程序使用此功能。在大多数流体动力电路 , 压缩性不是有利 ; 在许多 , 这是一个劣势。这意味着最好消除任何空气被困在一个液压回路允许更快的周期和使系统更加僵硬。

原文资料:

the Design of Bending Machine Hydraulic System

The benging machine belongs to a kind of forging Machinery.It is a major role in the metal processing industry. Products are widely applied to: light industry, aviation, shipping, metallurgy, instruments, electrical appliances, stainless steel products, steel structure construction and decoration industries.

Hydraulic system uses piston pump of pressure compensation to supply oil, the oil return throttle control, rational use of energy. Vertical hydraulic cylinder uses balance and locking measures, so it works safly and reliablely. At the same time hydraulic cylinders as the implementation of components haves great clamping force and shear force . When system shear plate material ,its performance is good

The design of the press systems, sheet metal shear system and hydraulic pump stations system have the circuit design and structure of the pumping station, layout and some non-standard components design. In the design process , it achieves structure compact and layout rational and manufacture simple.

An overview of the hydraulic system

Anny media (liquid or gas that flows naturally or can be forced to flow could be used to transmit energy in a fluid power system. The earliest fluid used was water hence the name hydraulics was applied to systems using liquids. In modern terminology, hydraulics implies a circuit using mineral oil. Figure 1-1 shows a basic power unit for a hydraulic system.(Note that water is making something of a comeback in the late '90s; and some fluid power systems today even operate on seawater. The other common fluid in fluid power circuits is compressed air. As indicated in Figure 1-2, atmospheric air -- compressed 7 to 10 times -- is readily available and flows easily through pipes, tubes, or hoses to transmit energy to do work. Other gasses, such as nitrogen or argon, could be used but they are expensive to produce and process.

Power is least understood by industry in general. In most plants there are few persons with direct responsibility for fluid power circuit design or maintenance. Often, general mechanics maintain fluid power circuits that originally were designed by a

fluid-power-distributor salesperson. In most facilities, the responsibility for fluid power systems is part of the mechanical engineers' job description. The problem is that mechanical engineers normally receive little if any fluid power training at college, so they are ill equipped to carry out this duty. With a modest amount of fluid power training and more than enough work to handle, the engineer often depends on a fluid power distributor's expertise. To get an order, the distributor salesperson is happy to design the circuit and often assists in installation and startup. This arrangement works reasonably well, but as other technologies advance, fluid power is being turned down on many machine functions. There is always a tendency to use the equipment most understood by those involved.

Fluid power cylinders and motors are compact and have high energy potential. They fit in small spaces and do not clutter the machine. These devices can be stalled for extended time periods, are instantly reversible, have infinitely variable speed, and often replace mechanical linkages at a much lower cost. With good circuit design, the power source, valves, and actuators will run with little maintenance for extended times. The main disadvantages are lack of understanding of the equipment and poor circuit design, which can result in overheating and leaks. Overheating occurs when the machine uses less energy than the power unit provides. (Overheating usually is easy to design out of a circuit. Controlling leaks is a matter of using straight-thread O-ring fittings to make tubing connections or hose and SAE flange fittings with larger pipe sizes. Designing the circuit for minimal shock and cool operation also reduces leaks.

A general rule to use in choosing between hydraulics or pneumatics for cylinders is: if the specified force requires an air cylinder bore of 4 or 5 in. or larger, choose hydraulics. Most pneumatic circuits are under 3 hp because the efficiency of air

compression is low. A system that requires 10 hp for hydraulics would use approximately 30 to 50 air-compressor horsepower. Air circuits are less expensive to build because a separate prime mover is not required, but operating costs are much higher and can quickly offset low component expenses. Situations where a 20-in. bore air cylinder could be economical would be if it cycled only a few times a day or was used to hold tension and never cycled. Both air and hydraulic circuits are capable of operating in hazardous areas when used with air logic controls or explosion-proof electric controls. With certain precautions, cylinders and motors of both types can operate in high-humidity atmospheres . . . or even under water.

When using fluid power around food or medical supplies, it is best to pipe the air exhausts outside the clean area and to use a vegetable-based fluid for hydraulic circuits.

Some applications need the rigidity of liquids so it might seem necessary to use hydraulics inthese cases even with low power needs. For these systems, use a combination of air for the

Power source and oil as the working fluid to cut cost and still have lunge-free control with options for accurate stopping and holding as well. Air-oil tank systems, tandem cylinder systems, cylinders with integral controls, and intensifiers are a few of the available components.

The reason fluids can transmit energy when contained is best stated by a man from the 17th century named Blaise Pascal. Pascal's Law is one of the basic laws of fluid power. This law says: Pressure in a confined body of fluid acts equally in all directions and at right angles to the containing surfaces. Another way of saying this is: If I poke a hole in a pressurized container or line, I will get PSO. PSO stands for pressure squirting out and puncturing a pressurized liquid line will get you wet. Figure 1-3 shows how this law works in a cylinder application. Oil from a pump flows into a cylinder that is lifting a load. The resistance of the load causes pressure to build inside the cylinder until the load

starts moving. While the load is in motion,pressure in the entire circuit stays nearly constant. The pressurized oil is trying to get out of the pump, pipe, and cylinder, but these mechanisms are strong enough to contain the fluid.When pressure against the piston area becomes high enough to overcome the load resistance,the oil forces the load to move upward. Understanding Pascal's Law makes it easy to see how all hydraulic and pneumatic circuits function.

Notice two important things in this example. First, the pump did not make pressure; it only produced flow. Pumps never make pressure. They only give flow. Resistance to pump flow causes pressure. This is one of the basic principles of fluid power that is of prime importance to troubleshooting hydraulic circuits. Suppose a machine with the pump running shows almost 0 psi on its pressure gauge. Does this mean the pump is bad? Without a flow meter at the pump outlet, mechanics might change the pump, because many of them think pumps make pressure. The problem with this circuit could simply be an open valve that allows all pump flow to go directly to tank. Because the pump outlet flow sees no resistance, a pressure gauge shows little or no pressure. With a flow meter installed, it would be obvious that the

pump was all right and other causes such as an open path to tank must be found and corrected.

Another area that shows the effect of Pascal's law is a comparison of hydraulic and mechanical leverage. Figure 1-4 shows how both of these systems work. In either case, a large force is offset by a much smaller force due to the difference in lever-arm length or piston area.Notice that hydraulic leverage is not restricted to a certain distance, height, or physical location like mechanical leverage is. This is a decided advantage for many mechanisms because most designs using fluid power take less space and are not restricted by position considerations. A cylinder, rotary actuator, or fluid motor with almost limitless force or torque can directly push or rotate the machine member. These actions only require flow lines to and from the actuator and feedback devices to indicate position.

The main advantage of linkage actuation is precision positioning and the ability to control without feedback.

At first look, it may appear that mechanical or hydraulic leverage is capable of saving energy.For example: 40,000 lb is held in place by 10,000 lb in Figure 1-4. However, notice that the ratio of the lever arms and the piston areas is 4:1. This means by adding extra force say to the 10,000-lb side, it lowers and the 40,000-lb side rises. When the 10,000-lb weight moves down a distance of 10 in., the 40,000-lb weight only moves up 2.5 in.

Work is the measure of a force traversing through a distance. (Work = Force X Distance..Work usually is expressed in foot-pounds and, as the formula states, it is the product of force in pounds times distance in feet. When a cylinder lifts a 20,000-lb load a distance of 10 ft, the cylinder performs 200,000 ft-lb of work. This action could happen in three seconds, three minutes, or three hours without changing the amount of work.

When work is done in a certain time, it is called power. {Power = (Force X Distance / Time.}A common measure of power is horsepower - a term taken from early days when most persons could relate to a horse's strength. This allowed the average person to evaluate to new means of power, such as the steam engine. Power is the rate of doing work. One horsepower is defined as the weight in pounds (force a horse could lift one foot (distance in one second (time. For the average horse this turned out to be 550 lbs. one foot in one second. Changing the time to 60 seconds (one minute, it is normally stated as 33,000 ft-lb per minute.

No consideration for compressibility is necessary in most hydraulic circuits

because oil can only be compressed a very small amount. Normally, liquids are considered to be

incompressible, but almost all hydraulic systems have some air trapped in them. The air bubbles are so small even persons with good eyesight cannot see them, but these bubbles allow for compressibility of approximately 0.5% per 1000 psi. Applications where this small amount of compressibility does have an adverse effect include: single-stroke air-oil

intensifiers; systems that operate at very high cycle rates; servo systems that maintain closetolerance positioning or pressures; and circuits that contain large volumes of fluid. In this book, when presenting circuits where compressibility is a factor, it will be pointed out along with ways to reduce or allow for it.

Another situation that makes it appear there is more compressibility than stated previously is if pipes, hoses, and cylinder tubes expand when pressurized. This requires more fluid volume to build pressure and perform the desired work. In addition, when cylinders push against a load, the machine members resisting this force may stretch, again making it necessary for more fluid to enter the cylinder before the cycle can finish.

As anyone knows, gasses are very compressible. Some applications use this feature. In most fluid power circuits, compressibility is not advantageous; in many, it is a disadvantage. This means it is best to eliminate any trapped air in a hydraulic circuit to allow faster cycle times and to make the system more rigid.