1、 中文 3275 字 附录一 外文翻译 A Short Course on apart of Automatic Transmissions The automatic transmission gearbox, as an important part in automobile driving system is used to make up the shortcoming of engine torque and rotary speed. It can changethevehicle speed and tyre torque in a big scope, cut off the
2、 power transfer from the engine, and also provides a reverse traveling direction for the vehicle. Therefore, the reasonability of the structure design of a transmission gearbox directly affects the vehicles dynamic performance. It is usually required shifting gears rapidly and conveniently, saving f
3、orce, and having a higher working efficiency and low working noises. The modern automatic transmission is by far, the most complicated mechanical component in todays automobile. Manual transmissions contain mechanical systems, hydraulic systems, electrical systems and computer controls, all working
4、together in perfect harmony which goes virtually unnoticed until there is a problem. This article will help you understand the concepts behind what goes on inside these technological marvels and what goes into repairing them when they fail. Transmission The transmission is a device that is connected
5、 to the back of the engine and sends the power from the engine to the drive wheels. An automobile engine runs at its best at a certain RPM (Revolutions Per Minute) range and it is the transmissions job to make sure that the power is delivered to the wheels while keeping the engine within that range.
6、 It does this through various gear combinations. In first gear, the engine turns much faster in relation to the drive wheels, while in high gear the engine is loafing even though the car may be going in excess of 70 MPH. In addition to thevarious forward gears, a transmission also has a neutral posi
7、tion which disconnects the engine from the drive wheels, and reverse； which causes the drive wheels to turn in the opposite direction allowing you to back up. Finally, there is the Park position. In this position, a latch mechanism (not unlike a deadbolt lock on a door) is inserted into a slot in th
8、e output shaft to lock the drive wheels and keep them from turning, thereby preventing the vehicle from rolling. There are two basic types of automatic transmissions based on whether the vehicle is rear wheel drive or front wheel drive. On a rear wheel drive car, the transmission is usually mounted
9、to the back of theengine and is located under the hump in the center of the floorboard alongside the gaspedal position. A drive shaft connects the rear of the transmission to the final drivewhich is located in the rear axle and is used to send power to the rear wheels. Powerflow on this system is si
10、mple and straight forward going from the engine, through thetorque converter, then through the transmission and drive shaft until it reaches the final drive where it is split and sent to the two rear wheels. On a front wheel drive car, the transmission is usually combined with the finaldrive to form
11、 what is called a transaxle. The engine on a front wheel drive car isusually mounted sideways in the car with the transaxle tucked under it on the side ofthe engine facing the rear of the car. Front axles are connected directly to thetransaxle and provide power to the front wheels. In this example,
12、power flows from the engine, through the torque converter to a large chain that sends the power through a 180 degree turn to the transmission that is along side the engine. From there, thepower is routed through the transmission to the final drive where it is split and sent tothe two front wheels th
13、rough the drive axles. There are a number of other arrangements including front drive vehicles wherethe engine is mounted front to back instead of sideways and there are other systemsthat drive all four wheels but the two systems described here are by far the mostpopular. A much less popular rear dr
14、ive arrangement has the transmission mounteddirectly to the final drive at the rear and is connected by a drive shaft to the torqueconverter which is still mounted on the engine. This system is found on the newCorvette and is used in order to balance the weight evenly between the front and rearwheel
15、s for improved performance and handling. Another rear drive system mounts everything, the engine, transmission and final drive in the rear. This rear engine arrangement is popular on the Porsche. Transmission Components The modern automatic transmission consists of many components and systemsthat ar
16、e designed to work together in a symphony of clever mechanical, hydraulic andelectrical technology that has evolved over the years into what many mechanicallyinclined individuals consider to be an art form. The cyeloid drive The cyeloid drive has the essential advnatages sueh as Wide rnage of tranms
17、ission ratio， eompact surtcture， high relibaility nad long wokrnig lief， So It gets borad application and its rsearchgoesdeep eonstnatly.Thedrivehasbeennotonlyappliedto traditionaltrnasmissionfield but also has alluring applieation in the aspeets of micro machine， robot gear ,preeision machine taans
18、mission， super mini cycloid drive，asrtonaut cquipment， measurment apparatus， tenement intelligence and high-tech equipment. In the family of the cycloid drive， the AFcycloid 一 pin wheel plnaetary driver educer is a new .Trnasmission device.Compared with the common cycloid drive， it has a series of a
19、dvantages such as small volume， lihgtweight， wide range of tranmsission， diversity transmission， long lief time， high rigidiyt， high slewing precision， stbale preeision， high effieiency and stable transmission.The designof thedrivedaoptsalotof advnacedtheories andtechnologymethoods andusesakindof in
20、novation stureurte， so the FA drive has overcome the defect of the traditional surtcture， enhnaccd the transmissin efficency， volume,and the transmission precision. Automatic transmissions contain many gears in various combinations. In amanual transmission, gears slide along shafts as you move the s
21、hift lever from oneposition to another, engaging various sized gears as required in order to provide thecorrect gear ratio. In an automatic transmission, however, the gears are neverphysically moved and are always engaged to the same gears. This is accomplishedthrough the use of planetary gear sets.
22、 One example of a way that this system can be used is by connecting the ring gear to the input shaft coming from the engine, connecting the planet carrier to the output shaft, and locking the sun gear so that it cant move. In this scenario, when we turn the ring gear, the planets will walk along the
23、 sun gear (which is held stationary) causing the planet carrier to mm the output shaft in the same direction as the input shaft but at a slower speed causing gear reduction (similar to a car in first gear). If we unlock the sun gear and lock any two elements together, this will cause all three eleme
24、nts to turn at the same speed so that the output shaft will mm at the same rate of speed as the input shaft. This is like a car that is in third or high gear. Another way that we can use a Planetary gear set is by locking the planet carrier from moving, then applying power to the ring gear which will cause the sun gear to turn in the opposite direction giving us reverse gear. The clutch pack is used, in this instance, to lock the planet carrier with the sun gear forcing both to turn at the same speed. If both the clutch pack and the band were
