【正文】 ugh the differential case) is a differentialpinion shaft on which are assembled two differentialpinion gears. Each rear car wheel has a separate axle, and there are two side gears splined to the inner ends of the two wheel axles. The two differentialpinion gears mesh with these two side gears. When the car is on a straight road, the two differentialpinion gears do not rotate on the pinion shaft, but they do exert pressure on the two side gears so that the side gears turn at the same speed as the ring gear, causing both rear wheels to turn at the same speed, differential case is supported in the carrier by two taperedroller side bearings. This assembly can be adjusted from side to side to provide the proper backlash between the ring gear and pinion and the required side bearing preload. This adjustment is achieved by threaded bearing adjusters on some units and the placement of selective shims and spacers on others.The differential case is supported in the carrier by two taperedroller side bearings. This assembly can be adjusted from side to side to provide the proper backlash between the ring gear and pinion and the required side bearing preload. This adjustment is achieved by threaded bearing adjusters on some units and the placement of selective shims and spacers on others.Transaxle final drive gears provide the means for transmitting transmission output torque to the differential section of the transaxle. The differential section of the transaxle has the same ponents as the differential gears in a RWD axle and basically operate in the same way. The power flow in transversely mounted power trains is in line with the wheels and therefore the differential unit does not need to turn the power 90 degrees.When the car rounds a curve, the outer wheel must turn faster than the inner wheel. To permit this, the two pinion gears rotate on their pinion shaft, transmitting more turning movement to the outer side gear than to the inner side gear. Thus, the side gear on the outerwheel axle turns more rapidly than the side gear on the innerwheel axle. This permits the outer wheel to turn more rapidly while the car is rounding the are two basic types of axle: dead axles and live axle. The dead axle does not rotate。 the wheel rotates on it. A mon example is the axle on a horse drawn wagon. Live axles are attached to the wheel so that both the wheel and the axle rotate together. Live axles are classified according to the manner in which they are supported: semifloating, threequarterfloating, and fullfloating.Propeller Shaft and Universal JointThe propeller shaft is a drive shaft to carry the power from the transmission to the rearwheel axles. It connects the transmission main, shaft carries through the propeller shaft to the differential at the rear axles. Rotary motion of the transmission main shaft carries through the propeller shaft to the differential, causing the rear wheels to rotate.The propellershaft design must take two facts into consideration. First, the engine and transmission are more or less rigidly attached to the car frame. Second, the rearaxle housing (with wheels and differential) is attached to the frame by springs. As the rear wheels encounter irregularities in the road, the springs press or expand. This changes the angle of drive and the distance between the transmission and the differential, and the propeller shaft may take care of these two changes. That is to say, as the rear axle housing, with differential and wheels, moves up and down, the angel between the transmission output shaft changes. The reason the propeller shaft shortens as the angel increases is that the rear axle and differential move in a shorter arc than the propeller shaft. The center point of the axlehousing arc is the rearspring or controlarm attachment to the frame. In order that the propeller shaft may take care of these two changes, it must incorporate two separate types of device. There must be one or more universal joints to permit variations in the angel of drive. There must also be a slip joint that permits the effective length of the propeller shaft to change.The propeller shaft may be solid or hollow, protected by an outer tube or exposed. Some applications include bearings at or near the propeller shaft center to support the shaft. The twosection propeller is supported by a center bearing and coupled together by universal joints. A universal joint is essentially a double hinged joint consisting of two Yshaped yokes, one on the driving shaft and the other on the driven shaft, and acrossshaped member called the spider. The four arms of the spider, known as trunnions, are assembled into bearings in the ends of the two shaft yokes. The driving shaft causes the spider to rotate, and the other two trunnions of the spider cause the driven shaft to rotate. When the two shafts are at an angel to each other, the bearings in the yokes permit the yokes to swing around on the trunnions with each revolution. A variety of universal joints have been used on auto mobiles, but the types now in most mon use are the spider and twoyoke, the constantvelocity, and the ballandtrunnion joints.A slip joint consists of outside splines on one shaft and matching internal splines in the mating hollow shaft, the splines cause the two shafts to rotate together but permit the two to move endwise with each other. This acmodates any effective change of length of the propeller shaft as the rear axles move toward or away from the car frame.差速器和后車軸差速器是后車軸體系的一部分，此體系包括差速器，后車軸，輪子和軸承。如果直線行車而不轉(zhuǎn)彎，則不需要差速器。然而，車轉(zhuǎn)彎時，外面輪子的速度必須比里面的輪子快。差速器保證車轉(zhuǎn)彎時外面輪子的旋轉(zhuǎn)比里面輪子快，同時給兩個后車輪提供動力。后車軸和輪子相連，并且在內(nèi)部的終端有傾斜齒輪。差速器在左車軸，但是能在車軸的軸承上獨立旋轉(zhuǎn)。差速器能使差速副齒輪作用于一個柄上，齒輪和兩個斜齒輪互相咬合。環(huán)行齒輪和差速裝置相連，從而使這個裝置在副齒輪旋轉(zhuǎn)時和環(huán)行齒輪一起旋轉(zhuǎn)。通過驅(qū)動力作用于副齒輪的柄上，驅(qū)動力進(jìn)入差速器。驅(qū)動副齒輪和大的環(huán)行齒輪互相咬合，從而使環(huán)行齒輪和副齒輪一起旋轉(zhuǎn)。環(huán)行齒輪上（穿過差速裝置）是一個差速副齒輪柄，柄上是兩個差速副齒輪。每個后車輪上各有一個車軸，兩個車輪的內(nèi)側(cè)邊緣都有兩個齒輪夾板。這兩個差速副齒輪和兩個邊緣齒輪互相咬合。當(dāng)車在公路上直線行駛時，兩個差速副齒輪不在副齒輪柄上旋轉(zhuǎn)，但是它們施力于兩個邊緣齒輪，從而使邊緣齒輪和環(huán)行齒輪速度