离合器外文翻译.doc

Transmission SystemA Basic Parts of the transmission systemThe transmission system applies to the components needed to transfer the drive from the engine to the road wheels. The main components and their purposes are(1) Clutch - to disengage the drive - to provide a smooth take-up of the drive(2) Gearbox - to increase the torque applied to the driving road wheels - to enable the engine to operate within a given range of speed irrespective of the vehicle speed - to give reverse motion of the vehicle - to provide a neutral position so that the engine can run without moving the vehicle(3) Final drive - to turn the drive through 90 - to reduce the speed of the drive by a set amount to match the engine to the vehicle(4) Differential - to allow the inner driving road wheel to rotate slower than the outer wheel when the vehicle is cornering, whilst it ensures that a drive is applied equally to both wheels. B Clutch and Clutch ServiceIn order to transmit the power of the engine to the road wheels of a car, a friction clutch and a change-speed gearbox are normally employed. The former is necessary in order to enable the drive to be taken up gradually and smoothly, while the latter provides different ratios of speed reduction from the engine to the wheels, to suit the particular conditions of running,A clutch performs two tasks:(1) it disengages the engine from the gearbox to allow for gear changing.(2) it is a means for gradually engaging the engine to the driving wheels, when a vehicle is to be moved from rest the clutch must engage a stationary gearbox shaft with the engine; this must be rotating at a high speed to provide sufficient power or else the load will be too great and the engine will start (come to test).C Clutch Action To start the engine, the driver must depress the clutch pedal. This disengages the gearbox from the engine. To move the car, the driver must reengage the gearbox to the engine. However, the engagement of the parts must be gradual. An engine at idle develops little power. If the two parts were connected too quickly, the engine would stall. The load must be applied gradually to operate the car smoothly.A driver depresses the clutch pedal to shift the gears inside the gearbox. After the driver releases the clutch pedal, the clutch must act as solid coupling device. It must transmit all engine power to the gearbox, without slipping.The clutch mechanism include three basic parts: driving member, driven member, operating members. The driving memberThe driving member consists of two parts: the flywheel and the pressure plate. The flywheel is bolted directly to the engine crankshaft and rotates when the crankshaft turns. The pressure plate is bolted to the flywheel. The result is that both flywheel and pressure plate rotate together. The driven member The driven member, or clutch disc, is located between the flywheel and pressure plate. The disc has a splined hub that locks to the splined input shaft on the gearbox .Any rotation of the clutch disc turns the input shaft .Likewise, any motion of the input shaft moves the clutch disc. The splines allow the clutch disc to move forward and backward on the shaft as it engages and disengages.The inner part of the clutch disc, called the hub flange, has a number of small coil springs. These springs are called torsional springs. They let the middle part of the clutch disc turn slightly on the hub. Thus, the springs absorb the torsional vibrations of the crankshaft. When the springs have compressed completely, the clutch moves back until the springs relax. In other words, the clutch absorbs these engine vibrations, preventing the vibrations from going through the drive train. Operating MembersThese are the parts that release pressure from the clutch disc. The operating members consist of the clutch pedal, clutch return spring, clutch linkage, clutch fork, and throwout bearing. The clutch linkage includes the clutch pedal and a mechanical or hydraulic system to move the other operating members.When the clutch pedal is depressed, the clutch linkage operates the clutch fork .The clutch fork, or release fork, moves the throwout bearing against the pressure plate release levers. These levers then compress springs that normally hold the clutch disc tightly against the flywheel.At this point, the torque of the engine cannot turn the gearbox input shaft. The gears in the gearbox may be shifted or the vehicle can be brought to a full stop.When the clutch pedal is released, the pressure plate forces the clutch disc against the flywheel. The clutch return spring helps raise the pedal.D Clutch Service The major parts of the clutch assembly need no maintenance or lubrication during normal service. However, all linkage parts need lubrication at points of contact. The linkage itself must be adjusted to prevent wear of the clutch disc. Free-play AdjustmentYou can make only one adjustment on the clutch linkage the free-play adjustment. Free play is the allowable space between the throwout bearing and the pressure plate release levers. This space is important because it prevents pressure on the levers that could keep the clutch from engaging fully. In other words, the throwout bearing must be slightly away from the pressure plate levers so that the bearing applies no pressure on the levers. On the other hand, there must not be too much free play between the bearing and the levers. With too much clearance, the clutch cannot fully disengaged when the driver press the clutch pedal to the floor. In most cases, you measure the free play at the clutch pedal, rather than at the bell housing.The free play allows some motion at the beginning of the clutch pedal travel, before the pedal meets resistance. Since the distance varies with the type of pressure plate, check the service manual. Usually, free play should be about 20 to 25mm. Free play can be adjusted at some point where the clutch linkage consists of threaded rods with locknuts. The rod closest to the clutch fork is the most common adjustment point. Begin by locating the rod and locknut beneath the vehicle. Then determine which way to turn the adjustment nuts to get the correct free play at the pedal. You can get a rough estimate of free play by moving the clutch fork to see if it still has some movement. The best way to make the adjustment is to loosen the locknut and move the adjustment nut a few turns. Then check the free play at the pedal. Continue making adjustments until you have the correct free play. When the free-play adjustment meets the manufacturers specification, tighten the locknut. Check the free-play adjustment every six months and make any adjustment. Clutches need adjustment that often, since free play decreases slightly as the clutch disc wears. However, the need for frequent adjustments means a problem in the clutch mechanism itself. There must be free play between the throwout bearing and pressure plate release levers. Problems can result from “riding the clutch”. A driver who rests one foot on the clutch pedal causes the throwout bearing to rub against the clutch release levers. As a result, the throwout bearing becomes worn quickly. Also, the clutch disc may wear out due to slippage because the parts are not fully engaged. Clutch FaultsThe following are the main faults:Slip failure of the surface to grip resulting in the driven plate revolving slower than the engine flywheel : Clutch gets hot and emits an odor.Spin or drag failure of the plates to separate resulting in noise from the gearbox when selecting a gear: most noticeable when the vehicle is stationary.Judder a vibration which occurs when the clutch is being engaged , i.e. when the vehicle is stationary.Fierceness sudden departure of the vehicle even though the pedal is being released gradually.E The Clutches（supplementary contract）A clutch is a friction device used to connect and disconnect a driving force from a driven member. In automotive applications, it is used in conjunction with an engine flywheel to provide smooth engagement and disengagement of the engine and manual transmission.Since an internal combustion engine develops little power or torque at low rpm, it must gain speed before it will move the vehicle. However, if a rapidly rotating engine is suddenly connected to the drive line of a stationary vehicle, a violent shock will result.So gradual application of load, along with some slowing of engine speed , is needed to provide reasonable and comfortable starts. In vehicles equipped with a manual transmission, this is accomplished by means of a mechanical clutch.The clutch utilizes friction for its operation. The main parts of the clutch are a pressure plate, and a driven disk. The pressure plate is coupled with the flywheel, while the driven disk is fitted to the disk by the springs so that the torque is transmitted owing to friction forces from the engine to the input shaft of the transmission. Smooth engagement is ensured by slipping of the disk before a full pressure is applied.The automobiles are equipped with a dry spring-loaded clutch. The clutch is termed “dry” because the surfaces of the pressure plate and driven disks are dry in contrast to oil-bath clutches in which the plate and disks operate in a bath of oil. It is called “springloaded” because the pressure plate and the driven disk are always pressed to each other by springs and are released only for a time to shift gears or to brake the automobile.In addition to the plate and disk, the clutch includes a cover, release levers, a release yoke, pressure springs and a control linkage. The clutch cover is a steel stamping bolted to the flywheel. The release levers are secured inside the cover on the supporting bolts. The outer ends of the release levers are articulated to the pressure plate. Such a construction allows the pressure plate to approach the cover or move away from it, all the time rotating with the cover or move away from it, all the time rotating with the flywheel. The springs spaced around the circumference between the pressure plate and the clutch cover clamp the driven disk between the pressure plate and the flywheel.The springs are installed with the aid of projections and sockets provided on the cover and pressure plate. The pressure plate sockets have thermal-insulation gaskets for protecting the springs against overheating.The clutch release mechanism can be operated either mechanically or hydraulically. The mechanically-operated release mechanism consists of a pedal, a return spring, a shaft with lever, a rod m release yoke lever, a release yoke, a release ball bearing with support and a clutch release spring. When the clutch pedal is depressed, the rod and shaft with yoke shift the release bearing and support assembly. The release bearing presses the inner ends of the release levers, the pressure plate is moved away from the driven disk and the clutch is disengaged. To engage the clutch , the pedal is released, the release bearing and support assembly is shifted back by the return spring thus releasing the release levers so that the pressure plate is forced by its springs towards the flywheel to clamp the driven disk and engage the clutch.The clutch hydraulically-operated release mechanism consists of a clutch pedal , clutch release spring , a main cylinder , a pneumatic booster, pipelines and hoses and a lever of the clutch release yoke shaft. Time main cylinder accommodates a piston with a cup. The pneumatic booster serves to decrease the pedal force required disengage the clutch. The booster includes two housings with the servo diaphragm clamped in between. The housing accommodates pneumatic, hydraulic and servo plungers. When the clutch pedal is pushed, the fluid pressure from the main cylinder is transmitted through the pipelines and hoses to the hydraulic and servo plungers of the pneumatic booster.The servo arrangement is intended for automatic change of the air pressure in the pneumatic cylinder proportionally to the force applied to the pedal. The plunger moves with the diaphragm, the outlet valve closes and the inlet valve opens thus admitting the compressed air to the pneumatic plunger piston. The forces created by the pneumatic and hydraulic plungers are added together and are applied through the push rod to the release yoke shaft lever; the lever turns the shaft and the release yoke, thus disengaging the clutch. After the clutch pedal is released, the outlet valve opens and the air from the cylinder is let out to the atmosphere.Automatic clutches were used in certain U.S. and European cars. American Motors “E-Stick” clutch eliminated the need for physical operation of the clutch system called “Hydrak”, which consisted of a fluid flywheel connected to a single, dry disk clutch.In the “E-Stick” set up, the pressure plate levers “engage” the clutch disk rather than “release” them. Also, the clutch remains disengaged until a servo unit is applied by oil pressure when the shift lever is placed “in gear” with the engine running.The “Hydrak” unit also begins operation when the lever is “in gear”. This activates a booster unit, which disengages the clutch disk. The hydraulic clutch parts are bridged over by a free-wheel unit, which goes into action when the speed of the rear wheel is higher than the speed of the engine. A special device controls engagement of the mechanical clutch, depending on whether the rear axle is in traction or is pushed by car momentum.A more-or-les unusual clutch pressure plate set-up is used on late model Chrysler and American Motors cars. Called a semi-centrifugal clutch, the pressure plate has six cylindrical rollers which move outward under centrifugal force until they contact the cover. As engine speed increases, the rollers wedge themselves between the pressure plate and cover so that the faster the clutch rotates, the greater the pressure exerted on the pressure plate and disk.传动系统A 基本传动系统的组成部份传动系统是将发动机动力转移到驱动轮的结构。主要的结构和目的是：(1)离合器 - 分离驱动； - 平顺的接合驱动；(2)变速器 - 增加提供给驱动轮的转矩； - 使发动机能够在给定的速度范围里面运转而不考虑的车速； - 使车辆的作倒退运动； - 提供一个齿轮的空档以便发动机能不需要移动车辆就运转；(3)减速器 - 使驱动转向90 ； - 减少一定的驱动转速并增大输入转矩；(4) 差速器 - 当车辆转弯行驶时允许内侧驱动轮比外侧驱动轮慢，同时驱动相等地作用于两轮。 B 离合器和离合器功用为了要将发动机动力传递到汽车驱动轮，通常使用磨擦离合器和变速器的组合。前者是为了要逐渐地而且平顺地接合并传递驱动 , 这是必需的，同时后者按不同比率减少两轮转速以适合特殊驾驶情况。离合器运行的二个作用：(1) 它将发动机与变速器分离使其换档；(2) 它可以解释为逐渐的接合驱动车轮与发动机 ；离合器必须以高速的转动来产生足够的动力，否则会因负荷过大，导致发动机熄火。 (进入静止状态)C 离合器工作原理为了启动发动机，驾驶员首先得踩下离合器踏板，使发动机与变速器分离。 为了使汽车能够行驶，驾驶员必须再接合发动机与变速器。然而，这种接合得是逐渐进行的。发动机在不工作状态时只能产生极小的动力。如果二个部份连接太快，发动机将会熄火。同时负荷必须被逐渐地加载才可以平顺地驾驶汽车。驾驶员踩下离合器踏板并挂档变速器。在驾驶员松开离合器踏板之后，离合器成为一个结合装置，将所有的发动机力量传递到变速器，而不会打滑。离合器机构包括三个基本的部份：主动部分，从动部分，操纵机构。主动部分主动部分分为两个部份: 飞轮和压力盘。飞轮直接地被闩在发动机的传动轴上并且随之一起转动。压力盘被闩在飞轮端面上与飞轮一起转动。从动部分从动部分，或离合器盘，位于飞轮和压力盘之间。离合器盘上有一个花键毂用来扣在变速器上与从动轴连接。离合器盘的任何转动都将带动从动轴转动，同样地，从动轴的任何运动都将传递到离合器盘。从动盘在从动轴上的前后移动、分离啮合通过滑动花键得以实现。离合器盘的内部，叫做法兰盘毂，有若干的小螺旋弹簧。这些弹簧叫做扭力弹簧。它们让离合器盘的中央部份在毂上些微地转动，因此弹簧吸收传动轴的扭转振动。当弹簧完全压缩时，离合器压回到原始位置，直到弹簧松开。换句话说，离合器吸收这些发动机振动，防止振动影响到驱动齿轮 操纵机构这些部份是用来释放离合器盘压力。操纵机构包括有离合器踏板，离合器回位弹簧，离合器联动装置，分离叉和分离轴承。离合器联动装置包括离合器踏板和机械的或液压系统用来联动另外的操纵机构。当离合器踏板被踩下的时候，离合器联动装置操纵着分离叉。分离叉，或者叫释放叉，使分离轴承反向于压力盘的分离杠杆移动。然后这些杠杆压缩弹簧将飞轮和离合器盘紧紧地撑开。此时，发动机的转矩还不能够带动变速器传动轴。变速器档位可能会因此加高或者导致车辆停止。当离合器踏板被松开的时候，压力盘强制性的将飞轮与离合器盘分开。在离合器回位弹簧的帮助下踏板逐渐的升起。D 离合器功用离合器的主要部份在正常的服务期间不需要维护或者是润滑。然而，所有的联动装置部份在接点处是需要润滑的。联动装置本身需要一定的调整从而避免发生与离合器盘的磨损。自由行程调整你只能在离合器联动装置上作一个调整自由行程的调整。自由行程是存在于离合器盘分离杠杆和分离轴承中允许的空间里的一段行程。这个空间是非常重要的，因为它能抵制杠杆上的压力从而组织离合器的啮合。换句话说，分离轴承些微地离开压力盘杠杆使轴承不产生作用于杠杆的压力。另一方面，在轴承和杠杆之间又不能有太多的自由行程。如果有太多的间隙，即使当驾驶员将离合器踏板踩死，离合器也不能够完全的起到分离作用。在大部份的情形下，你应该在离合器踏板上测量自由行程，而不是在外壳。在踏板遇到阻力之前，在刚踩下踏板的时候，自由行程允许一些移动发生。当距离随着压力盘的类型的改变而改变时，核对服务手册来确定自由行程。通常自由行程应该是大约 20 到 25 毫米。 在由穿杠和锁紧螺母组成的离合器联动装置的地方自由行程可以被调整。最接近分离叉的竿是最常用的调整点。从在车辆之下寻找竿和锁紧螺母的位置开始。然后决定选一种调整螺母的方法来获得正确的踏板自由行程。如果它仍然有一些移动，你能通过移动分离叉来粗糙估计一个自由行程。调整的最好方式是松开锁紧螺母并且旋转螺帽。然后在踏板上核查自由行程。继续这样调整下去，直到你获得正确的自由行程。当自由行程调整到制造厂的规格时，勒紧锁紧螺母。 每六个月检查自由行程并且作一些调整。离合器需要时常调整，因为自由行程会些微地减少比如与离合器盘的磨损。然而，频繁的调整那就意味着离合器机构本身已经出现问题了。在分离轴承和压力盘分离杠杆之间一定有自由行程。而毛病可能起因于对离合器的“消遣”。驾驶员将一支脚搁在离合器踏板上使分离轴承与离合器分离杠杆产生摩擦。如此结果，分离轴承磨损的越来越快。同时由于部份装置没有完全啮合，因此离合器盘也因为滑动而被磨损。 离合器故障下列各项是主要的故障:打滑 表面附者不充分造成从动片回转的比发动机飞轮更慢：离合器很热而且发出气味。自转或咬死