【正文】 ine in order to exert the best performance, it is necessary to have a variablespeed devices, to coordinate the engine speed and the actual wheel speed. Transmission process in the car, in between the engine and the wheels have a different gear ratio, by shifting the engine can work at their best performance of state power. Transmissions are the development trend of more and more plex, increasingly high degree of automation, automatic transmission will be the mainstream of the future. Transmission type. Automotive automatic transmission has three mon forms: namely, Automatic Transmission (AT), mechanical stepless automatic transmission (CVT), electriccontrolled mechanical automatic transmission (AMT). At present, the most widely used is the AT, AT almost bee synonymous with automatic transmission. AT Torque by Torque, and plaary gear and hydraulic control system ponents, through the hydraulic transmission and gear portfolio approach to achieve variablespeed torque variation. One of Hydraulic Torque is the most important parts, which pump wheels, turbines and ponents, such as guide pulley of the transmission of both torque and the role of clutch. AT pared with, CVT save the plex and cumbersome bination of variablespeed gear transmission, but the two groups to carry out variablespeed drive pulley. By changing the driving wheel and driven wheel contact belt speed radius. Canceled because of gear, so the transmission ratio can change speed more smoothly, without shifting sense of the sudden jump. AMT and Automatic Transmission (AT) are the same class has automatic transmission. It is in general based on the manual transmission, through the installation of microputercontrolled electric device to replace the original finish by the manual operation of the clutch of separation, joint, and block transmission of the election, motion shift, automatic shift implementation. 23 The general structure of automobile transmission: 1. Easy transmission of the basic structure: the shell, transmission and manipulation of some parts. (1)Shell: Shell is the basic pieces of support for the installation of transmission and storage of all parts lubricants. Has installed its bearing on the precision boring. Transmission under varying load, so the stiffness of the shell should be enough, there is to strengthen the wall, the shape of the plex, as many castings (gray cast iron materials, monly used HT200). In order to facilitate the installation, transmission and manipulation of some Split parts are frequently made, cover with the housing connected by bolts and reliable positioning. Shell has e on up, I put the oil, check oil foot mouth, should also be taken into heat dissipation. (2)Transmission parts: is the gear, shaft, bearings and other transmission parts. Geometry axis through strength, stiffness calculation. Mainly due to decide on the stiffness, while the carbon steel and alloy steel elastic modulus almost equal, so the general use of carbon steel (monly used 45 steel). Only one gear with the shaft or axle load made serious only by steel. Shaft and gear for many spline connection (for neutral good, reliable transmission of power, a small pressive stress, etc.). Spline shaft bearing parts and let the surface hardening treatment by the Department. Shaft with rolling bearing supports many, easy lubrication, high efficiency, small radial clearance, axial positioning should be reliable. Many ways to use splash lubrication (υ 25m / s, as long as the appropriate viscosity apparently succumbed to the wall). (3)to manipulate parts: the main ponents located inside the transmission cover. position of the structural characteristics of transmission: there is easy and efficient transmission, the advantages of simple easytouseJun mine but a few files, i changed the scope of small (traction, speed small), file number should be taken only at certain limited Cut used. If the increase in the scope of i, then increase the size so that transmission, axle span increase, both in order to increase the fileaxis span of a few do not make too large, transmission can be formed. The position of the socalled transmission, usually from both a bination of easy transmission, one of a few more files as the main transmission, less transmission known as the deputy. Transmission ponent of advantages: 24 (1)can reduce the number of gears, and a few more files to reduce the number of gear the more obvious advantages. Easy pared with the transmission, it can shorten the length of shaft to reduce the transmission of the external size and weight, and can easily be more than one reverse. Into the file so the current number of files more than six hours, almost all transmission ponents. (2)transmission: the rate of change of Ω than large: if the main transmission gear ratio change rate Ωzu = 3, Vice transmission Ωfu = 4 is Ω = 12。s most advanced Automatic Transmission (AT) has been. Automatic Transmission For example, it has an internal gear is also divided, but the abolition of the clutch. The more gear, then shift, the better the ride fort. At present, mon automatic transmission are generally fourspeed, that is, block has four forward. 6L80 has six forward gear, the number of teeth than the one block are separately ,3 block ,2 block ,6 block ,5 block ,4 block . Obviously, it is more than 4speed automatic transmission with a greater ratio and smaller ratio of the difference, it is more smooth when speed. Outside the block a few more besides, 6L80 also has a lot of unique special skills: 25 Driver shift control system (DSC) through its driver into a vehicle without the clutch from the automatic fivespeed, highperformance. Drivers under the food stalls to the DSC on the location, the light touch can be specified at the scope of the neat, smooth implementation block additi