自动变速器英文文献翻译

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1、精品文档，仅供学习与交流，如有侵权请联系网站删除毕业设计外文翻译THE RESEARCHS OFAMT SHIFTING SCHEDULESThe modern automatic transmission is by far，the most complicated mechanical component in todays automobile. It is a type of transmission that sifts itself. A fluid coupling or torque converter is used instead of a manually operate

2、d clutch to connect the transmission to the engine.There are two basic types of automatic transmission based on whether the vehicle is rear wheel drive or front wheel drive. On a rear wheel drive car，the transmission is usually mounted to the back of the engine and is located under the hump in the c

3、enter of the floorboard alongside the gas pedal position. A drive shaft connects the transmission to the final drive which is located in the rear axle and is used to send power to the rear wheels. Power flow on this system is simple and straight forward going from the engine，through the torque conve

4、rter，then trough the transmission and drive shaft until it reaches the final drive where it is split and sent to the two rear transmission.On a front wheel drive car，the transmission is usually combined with the final drive to form what is called a transaxle. The engine on a front wheel drive car is

5、 usually mounted sideways in the car with the transaxle tucked under it on the side of the engine facing the rear of the car. Front axles are connected directly to the transaxle and provide power to front wheels. In this example，power floes from the engine，through the torque converter to a larger ch

6、ain that sends the power through a 180 degree turn to the transmission that is along side the engine. From there，the power is routed through the transmission to the final drive where it is split and sent to the two front wheels through the drive axles. There are a number of other arrangements includ

7、ing front drive vehicles where the engine is mounted front to back instead of sideways and there are other systems that drive all four wheels but the two systems described here are by far the most popular. A much less popular rear and is connected by a drive shaft to the torque converter which is st

8、ill mounted on the engine. This system is found on the new Corvette and is used in order to balance the weight evenly between the front and rear wheels for improved performance and handling. Another rear drive system mounts everything，the engine，transmission and final drive in the rear. This rear en

9、gine arrangement is popular on the Porsche。 The modern automatic transmission consists of many components and systems that designed to work together in a symphony of planetary gear sets，the hydraulic system, seals and gaskets，the torque converter，the governor and the modulator or throttle cable and

10、computer controls that has evolved over the years into what many mechanical inclined individuals consider to be an art from. Here try to used simple，generic explanation where possible to describe these systems.1）Planetary gear sets Automatic transmission contain many gears in various combinations. I

11、n a manual transmission，gears slide along shafts as you move the shift lever from one position to another，engaging various sizes gears as required in order to provide the correct gear ratio. In an automatic transmission，how ever，the gears are never physically moved and are always engaged to the same

12、 gears. This is accomplished through the use of planetary gear sets.The basic planetary gear set consists of a sun gear，a ring and two or more planet gears，all remaining in constant mesh. The planet gears are connected to each other through a common carrier which allows the gears to spin on shafts c

13、alled “pinions” which are attached to the carrier.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

14、the ring gear，the planets will “walk” along the sun gear ( which is held stationary ) causing the planet carrier to turn 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 tw

15、o elements together，this will cause all three elements to turn at the same speed so that to output shaft will turn at the same rate of speed as the input shaft. This is like a car that is third or high gear. Another way we can use a planetary gear set is by locking the planet carrier from moving，the

16、n applying power to the ring gear which will cause the sun gear to turn in opposite direction giving us reverse gear.The illustration in Figure shows how the simple system described above would look in an actual transmission. The input shaft is connected to the ring gear，the output shaft is connecte

17、d to the planet carrier which is also connected to a “Multi-disk” clutch pack. The sun gear is connected to drum which is also connected to the other half of the clutch pack. Surrounding the outside of the drum is a band that can be tightened around the drum when required to prevent the drum with th

18、e attached sun gear from turning.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 released，the system would be in neutral. Turning the input shaft would turn the planet gears agains

19、t the sun gear，but since noting is holding the sun gear，it will just spin free and have no effect on the output shaft. To place the unit in first gear，the band is applied to hold the sun gear from moving. To shift from first to high gear，the band is released and the clutch is applied causing the out

20、put shaft to turn at the same speed as the input shaft. Many more combinations are possible using two or more planetary sets connected in various way to provide the different forward speeds and reverse that are found in modern automatic transmission. 2）Clutch pack A clutch pack consists of alternati

21、ng disks that fit inside a clutch drum. Half of the disks are steel and have splines that fit into groves on the inside of the drum. The other half have a friction material bonded to their surface and have splines on the inside edge that fit groves on the outer surface of the adjoining hub. There is

22、 a piston inside the drum that is activated by oil pressure at the appropriate time to squeeze the clutch pack together so that the two components become locked and turn as one. 3）One-way Clutch A one-way clutch ( also known as a “sprag” clutch ) is a device that will allow a component such as ring

23、gear to turn freely in one direction but not in the other. This effect is just like that bicycle，where the pedals will turn the wheel when pedaling forward，but will spin free when pedaling backward. A common place where a one-way clutch is used is in first gear when the shifter is in the drive posit

24、ion. When you begin to accelerate from a stop，the transmission starts out in first gear. But have you ever noticed what happens if you release the gas while it is still in first gear ? The vehicle continues to coast as if you were in neutral. Now，shift into Low gear instead of Drive. When you let go

25、 of the gas in this case，you will feel the engine slow you down just like a standard shift car. The reason for this is that in Drive，one-way clutch is used whereas in Low，a clutch pack or a band is used.4）Torque Converter On automatic transmission，the torque converter takes the place of the clutch f

26、ound on standard shift vehicles. It is there to allow the engine to continue running when the vehicle comes to a stop. The principle behind a torque converter is like taking a fan that is plugged into the wall and blowing air into another fan which is unplugged. If you grab the blade on the unplugge

27、d fan，you are able to hold it from turning but as soon as you let go，it will begin to speed up until it comes close to speed of the powered fan. The difference with a torque converter is that instead of using air it used oil or transmission fluid，to be more precise. A torque converter is a lager dou

28、ghnut shaped device that is mounted between the engine and the transmission. It consists of three internal elements that work together to transmit power to the transmission. The three elements of the torque converter are the pump，the Turbine，and the Stator. The pump is mounted directly to the torque

29、 housing which in turn is bolted directly to the engines crankshaft and turns at engine speed. The turbine is inside the housing and is connected directly to the input shaft of the transmission providing power to move the vehicle. The stator is mounted to a one-way clutch so that it can spin freely

30、in one direction but not in the other. Each of the three elements has fins mounted in them to precisely direct the flow of oil through the converter. With the engine running，transmission fluid is pulled into the pump section and is pushed outward by centrifugal force until it reaches the turbine sec

31、tion which stars it running. The fluid continues in a circular motion back towards the center of the turbine where it enters the stator. If the turbine is moving considerably slower than the pump，the fluid will make contact with the front of the stator fins which push the stator into the one way clu

32、tch and prevent it from turning. With the stator stopped，the fluid is directed by the stator fins to re-enter the pump at a “help” angle providing a torque increase. As the speed of the turbine catches up with the pump，the fluid starts hitting the stator blades on the back-side causing the stator to

33、 turn in the same direction as the pump and turbine. As the speed increase，all three elements begin to turn at approximately the same speed. Sine the 80s，in order to improve fuel economy，torque converters have been equipped with a lockup clutch which locks the turbine to the pump as the vehicle reac

34、hes approximately 40-50 mph. This lockup is controlled by computer and usually wont engage unless the transmission is in 3rd or 4th gear.5）Hydraulic System The hydraulic system is a complex maze of passage and tubes that sends that sends transmission fluid and under pressure to all parts of the tran

35、smission and torque converter and. Transmission fluid serves a number of purpose including : shift control ,general lubrication and transmission cooling。Unlike the engine ,which uses oil primary for lubrication ,every aspect of a transmission s function is dependant on a constant supply of fluid is

36、send pressure. In order to keep the transmission at normal operating temperature，a portion of the fluid is send to through one of two steel tubes to a special chamber that is submerged in anti-freeze in the radiator. Fluid passing through this chamber is cooled and then returned to the transmission

37、through the other steel tube. A typical transmission has an avenge of ten quarts of fluid between the transmission，torque converter，and cooler tank，In fact，most of the components of a transmission are constantly submerged in fluid including the clutch packs and bands. The friction surfaces on these

38、parts are designed to operate properly only when they are submerged in oil.6）Oil Pump The transmission oil pump ( not to confused with the pump element inside the torque converter ) is responsible for producing all the oil pressure that is required in the transmission. The oil pump is mounted to fro

39、nt of the transmission case and is directly connected to a flange on the engine crankshaft，the pump will produce pressure whenever the engine is running as there is a sufficient amount of transmission fluid available. The oil enters the pump through a filter that is located at bottom of the transmis

40、sion oil pan and travels up a pickup tube directly to the oil pump. The oil is then sent，under pressure to the pressure regulator，the valve body and the rest of the components，as required. 7）Valve Body The valve body is the control center of the automatic transmission. It contains a maze of channels

41、 and passages that direct hydraulic fluid to the numerous valves which when activate the appropriate clutch pack of band servo to smoothly shift to the appropriate gear for each driving situation. Each of the many valves in the valve body has a specific purpose and is named for that function. For ex

42、ample the 2-3 shift valve activates the 2nd gear up-shift or the 3-2 shift timing valve which determines when a downshift should occur. The most important valve and the one that you have direct control over is the manual valve. The manual valve is directly connected to the gear shift handle and cove

43、rs and uncovers various passages depending on what position the gear shift is paced in. When you place the gear shift in Drive，for instance，the manual valve directs fluid to the clutch pack ( s ) that activates 1st gear. It also sets up to monitor vehicle speed and throttle position so that it can d

44、etermine the optimal time and the force for the 1-2 shift. On computer controlled transmission，you will also have electrical solenoids that are mounted in the valve body to direct fluid to the appropriate clutch packs or bands under computer control to more precisely control shift points.8）Seals and

45、 Gaskets An automatic transmission has many seals and gaskets to control the flow of hydraulic fluid and to keep it from leaking out. There are two main external seals : the front seal and the rear seal. The front seal seals the point where the torque converter mounts to the transmission case. This

46、seal allows fluid to freely move from the converter to the transmission but keeps the fluid from leaking out. The rear seal keeps fluid from leaking past the output shaft.A seal is usually made of rubber ( similar to the rubber in a windshield wiper blade ) and is used to keep oil from leaking past

47、a moving part such as a spinning shaft. In some cases，the rubber is assisted by a spring that holds he rubber in close contact with the spinning shaft.A gasket is a type of seal used to seal two stationary parts that are fasted together. Some common gasket materials are : paper，cork，rubber，silicone

48、and soft metal.Aside from the main seals，there are also a number of other seals and gasket that vary from transmission to transmission. A common example is the rubber O-ring that seals the shaft for the shift control lever. This is the shaft that you move when you manipulate the gear shifter. Anothe

49、r example that is common to most transmission is the oil pan gasket. In fact，seals are required anywhere that a device needs to pass through the transmission case with each one being a potential source for leaks.9）Computer Controls The computer uses sensors on the engine and transmission to detect s

50、uch things as throttle position，vehicle speed，engine speed，engine load，stop light switch position，etc. to control exact shift points as well as how soft or firm the shift should be. Some computerized transmission even learn your driving style and constantly adapt to it so that every shift is timed p

51、recisely when you would need it.Because of computer controls，sports models are coming out with the ability to take manual control of the transmission as through it were a stick shift lever through a special gate，then tapping it in one direction or the other in order to up-shift at will. The computer

52、 monitors this activity to make sure that the driver dose not select a gear that could over speed the engine and damage it.Another advantage to these “ smart” transmission is that they have a self diagnostic mode which can detect a problem early on and warn you with an indicator light on the dash. A

53、 technician can then plug test equipment in and retrieve a list of trouble codes that will help pinpoint where the problem is.Vehicular Automatic Transmission can be divided into three types: Automatic Transmission(AT), Automated Mechanical Transmission (AMT) and Continuously Variable Transmission(C

54、VT). LMT has become a kind of transmission that is full of potentiality, due to its high transfer efficiency, low cost and easiness to manufacture.The research on AMT shifting performance is key technology in the developing. Shifting performance directly influence the market competition and industri

55、alization of AMT.AMT has good market expectation, but during the shifting procedure, the power must be cut off which causes the poor shifting performance than AT and CVT. Only through improving the shitting performance can the commercial competence be established. So the virtual important thing is t

56、o find the way to improve shifting performance.The development of AMT can be divided into three phases: semi-automatic, automatic, and intelligent. The two major part of AMT are: the hardware including the mastered object, executor , sensors and TCU; and the software performing the control strategy.

57、The performance of AT shift influences greatly the performance of the vehicle. So the research on at shift quality is an important problem in the domain of AT researching. 5hi代q notify control of AT is accomplished by electronic and hydraulic system. To shift smoothly, according the real time thrott

58、le calve opening and vehicle speed signal, the controller sends electronic signals to control oil pressure changing curve of the applying elements. this paper analyzes and research detailed shift quality control system, the analyzing model of shifting process and pressure changing curve of the apply

59、ing elements. Firstly this paper summaries the existing evaluated quota of shift quality, and fully analyzes and introduces the existing control manner of AT shift quality. To meet the needs of research of vehicle starting and the real time control of shift, this paper puts forward a simplified mode

60、l of engine-torque and a dynamics model of AT shifting process. Through the applying of the established model, this paper fully analyses the process al the AT shitting. This paper drafts the proper oil pressure changing curve of the applying elements which can improve the AT shift quality, and gives

61、 the material calculated methods of the AG4 AT. This paper simulates the AG4 ATs shifting process of 2H to 3H.The results of the simulation validate the established simplified models and the expected oil pressure changing curve. This paper fully analyses the mechanism of the pressure regulating and

62、flow controlling system of the AG4 AT, and preparatory discusses the design of the block-diagram of the shift quality control. This paper test the control system and hydraulic system of the AG4 AT by the AT hydraulic-electronic testing-bed. The result of the test validates the correction of these an

63、alyses. Automated Mechanical Transmission, as so called AMT, is a new-style transmission system.AMT technology applies the automatic. technology to the manual mechanical transmission and makes the selection-gear, shift, clutch and throttle implement automatically. AMT technology is suitable for the

64、situation of our country, and has an expansive market arid development foreground. Shift schedules decide the time to shill and are the soul of the AMT. When the AMT is working, by comparing the states of the vehicle with the optimal shift schedules, the AMT decides the optimal shift time and achiev

65、es the shill automatically. This will lessen the tiredness of the drier and improve the safety. all the same time, the power and fuel-economy of the vehicle can also be improved. The author chooses the shift schedule as the key technology problem to be researched and the main study aim of this thesis is to get the optimal shill schedules for the AMT and so improve the power and fuel-economy of the vehicle. Through analyzing the influence factors of power and fuel-economy far the automobile