1、附 录 1 Drive Axle All vehicles have some type of drive axle/differential assembly incorporated into the driveline. Whether it is front, rear or four wheel drive, differentials are necessary for the smooth application of engine power to the road. The drive axle must transmit power through a 90 angle.
2、The flow of power in conventional front engine/rear wheel drive vehicles moves from the engine to the drive axle in approximately a straight line. However, at the drive axle, the power must be turned at right angles (from the line of the driveshaft) and directed to the drive wheels. This is accompli
3、shed by a pinion drive gear, which turns a circular ring gear. The ring gear is attached to a differential housing, containing a set of smaller gears that are splined to the inner end of each axle shaft. As the housing is rotated, the internal differential gears turn the axle shafts, which are also
4、attached to the drive wheels. The differential is an arrangement of gears with two functions: to permit the rear wheels to turn at different speeds when cornering and to divide the power flow between both rear wheels. (1)The accompanying illustration has been provided to help understand how this occ
5、urs. The drive pinion, which is turned by the driveshaft, turns the ring gear. (2)The ring gear, which is attached to the differential case, turns the case. (3)The pinion shaft, located in a bore in the differential case, is at right angles to the axle shafts and turns with the case. (4)The differen
6、tial pinion (drive) gears are mounted on the pinion shaft and rotate with the shaft. (5)Differential side gears (driven gears) are meshed with the pinion gears and turn with the differential housing and ring gear as a unit. (6)The side gears are splined to the inner ends of the axle shafts and rotat
7、e the shafts as the housing turns. (7)When both wheels have equal traction, the pinion gears do not rotate on the pinion shaft, since the input force of the pinion gears is divided equally between the two side gears. (8)When it is necessary to turn a corner, the differential gearing becomes effectiv
8、e and allows the axle shafts to rotate at different speeds. As the inner wheel slows down, the side gear splined to the inner wheel axle shaft also slows. The pinion gears act as balancing levers by maintaining equal tooth loads to both gears, while allowing unequal speeds of rotation at the axle shafts. If the vehicle speed remains constant, and the inner wheel slows down to 90 percent of vehicle speed, the outer wheel will speed up to 110 percent. However, because this
