1 Driving Axle automobile driving axle The driving axle is one of cross bars supporting a vehicle, on which the driving wheels turn .The driving axle includes a housing ,an axle drive ,a differential , tow axle shafts (half axles ),and final drives (if any ) . The axle .or main, drive is a drive-line unit that increases the torque delivered by the transmission and transmits it to the driving wheels, via the differential. In automobiles, the axle drive shaft, usually called the propeller shaft. The axle drive may be a Single or a double-stage type, the former comprising a pair of gears and the latter .tow pairs of gear. Drive pinion I may be made integral with its shaft, or it may be detachable from the shaft. Driving gears and are usually made in the form of detachable gear rings that are bolted or riveted to the differential case .Alex drive bevel pinions and gears are made with helical teeth in order to reduce noise in operation. The tow-stage axle drive consists of a pair of bevel gears and a pair of spur gears. Drive bevel pinion drives bevel gear that is fixed to the flange of the intermediate shaft made integral with 2nd stage driving spur gear .Gears meshes with driven spur gear which is fastened to the case rotates in taper roller bearings installed in the differential carrier that makes part of the driving axle housing. The differential is a drive-line unit that divides the torque applied to it between the tow axle shafts and allows one driving wheel to turn at a different speed from the other. The differential consists of case, cross or spider pinion .and side gears, also known as axle gears .the differential pinions are freely mounted on the cylindrical arms of the spider, which is held in the differential case, and remain in constant mesh with the differential side gears. 2 When the automobile is moving down a straight and even road, both driving wheels meet with one and the same rolling resistance. In this case, axle driven gear, or differential ring gear, causes the differential case to rotate .when the differential case rotates pinions and their spider arms move around in a circle with tow differential side gears are meshed with the pinions, the side gears must rotate, causing the axle shafts and their associated driving wheels to turn. With equal resistance applied to each wheel, the differential pinions do not rotate. They apply equal torque to the side gears and therefore both driving wheels rotate at one and the same speed is unequal ,the differential pinions rotate on their spider arms as well as drive round with the differential case .supposing that one of the axle shaft is prevented from rotating ,the differential pinions would have to walk around the stationary side gear ,causing the other side gear to rotate at twice its normal speed .You can now see how the differential can allow one driving wheel to turn faster than the other . Whenever the automobile goes around a turn ,the outer driving wheel travels a greater distance than the inner drive wheel .the inner wheel speeds up proportionately ,thanks to the differential pinions that rotate on their spider arms and ,rolling around the slower side gear send more rotary motion to the outside wheel. The differential side gears are splined on to the inner ends of the axle shafts .The other ends of the shafts are attached to the driving wheel hubs by means of flanges .Trucks use full floating axle shafts .Such axle shafts are acted upon by torque only .All the other loads acting on the driving wheels are taken by the driving axle housing, because the wheel hubs are supported by bearings mounted on the housing. Driving axle of general-purpose wheeled tractor General-purpose wheeled tractors are a four-wheel drive type, they have tow driving axles-front and rear .Both axles are similar in construction, expect for the housing. Each driving axle consist if a housing, an axle drive ,a differential ,and final drives .The front and rear-axles drives are interchangeable and comprise a pair of spiral bevel gears . The axle drive pinion is made integral with a sha ft that is 3 supported by tow taper roller bearings installed in axle drive pinion carrier .The latter is accommodated in differential carrier and is fixed to it by bolts. The flange of the axle drive pinion carrier is provided with threaded holes to fit puller screws that are used to remove the axle drive pinion carrier from the differential carrier .The position of the drive pinion relative to the centerline of the axle is adjust by means of a pack of shims placed under the flange of the drive pinion carrier Shims palace under the cone of the front bearing are used to adjust the preload on the drive pinion bearings. Splined to adjust the preload on the drive pinion shaft is universal-joint flange .The axle drive gear is bolted to the differential case flange. THE DIFFERENTIAL consists of case, four pinions, and tow side gears .The differential case comprise tow halves that are bolted together and supported by taper roller bearings installed in the differential carrier .Screwed in the bearings housing from the outside are nuts used to adjust the backlash between the ring gear and drive pinion teeth and the side bearing preload. Welded to the top of the driving axle housing at both its ends are spring pads .The housing of both its ends are spring axels are provided with filler ,overflow ,and drain holes closed by plugs .Both housing also have vents ,The rotating components of the driving axles are lubricated with transmission oil . As distinct from the automobiles considered in this text, all tractors include final drives in their power trains .The final drives of general-purpose wheel tractors are referred to as wheel-hub reduction gears. While transmitting power to the driving wheels, wheel-hub reduction can increase their torque .These are planetary reduction gear sets consist of sun gear ,or wheel ,three planet ,or pinion ,gears ,planet or pinion ,carrier .stationary internal ,or ring ,gear ,and housing. The sun gear is splined to the outer end of the axle shaft is splined to the differential side gear .The cylindrical planet gears are in constant mesh with both the sun gear and the ring gear and are free to rotate on roller bearings mounted on shafts that are attached to the planet carrier .The planet carrier is fasted to the reduction gear housing by means of studs and nuts .The flange of housing ,driving wheel brake drum 4 13,and wheel hub are clamped together by bolts .The planet carrier and reduction gear housing form the driven part of the planetary gear set and rotate with the driving wheel of the tractor .The driving gear hub is supported by taper roller bearings mounted on axle shaft housing ,or axle sleeve .The axle sleeve is connected to the stationary ring gear by means of adapter hub that has internal splines and external teeth . The splines are meshed with matching splines on the axle sleeve, and the teeth are meshed with internal teeth ring gear. Wheels and its maintain Modern wheeled tractors and automobiles use pneumatic-tired disc wheels. As a result of the driving wheel tires gripping the road, the rotary motion of the wheels is transformed into the translational motion of the tractor or automobile. According to their purpose, wheels are classified as driving .driven steerable, and combination types. Trucks and general-purpose wheeled tractors have all their wheels of one and the same size .Row-crop tractors have their rear wheels larger than the front wheels .The rear wheels carry the major proportion of the load due to the weight of the tractor .The front wheels are loaded lighter and this makes them easier to turn and provide good directional steering stability, which is essential for row-crop work. A TRUCK WHEEL consists of disc and flat base rim that is made integral with it, while the other flange is formed by detachable side ring that is held to the rim by split lock ring on the rim .which doubles as a side ring and a lock ring. The wheel disc is provided with holes for mounting the wheel on the wheel mounting bolts ,or wheel studs ,on the wheel hub ,where it is fixed by nuts .Both the holes and the nuts are tapered to ensure exact location of the wheel on its hub .The rear driving axles of trucks carry tow wheels at each end .The inner wheels are held to the hubs by cap nuts that are threaded both on the inside and on the outside .and the outer wheels are mounted on the cap nuts and fixed in place by taper nuts screwed on the nuts . The wheel nuts on the right side of truck have right-hand threads, whereas the nuts on the left side of the truck are threaded left-hand .The reason is to tighten the nuts, not loosen them, and thus prevent them from working loose on acceleration and 5 braking. An automobile pneumatic tire consists of casing, inner tube, and flap .The tire casing comprises tread, side walls, and beads .Tires for good roads use small tread patterns, while those for bad roads or cross country service large tread patterns. The inner tube is made in the form of a hollow elastic rubber doughnut that is inflated with air after it is installed inside the tire and the tire is put on the whe el rim .The inner tube is inflated through tire valve that consists of housing 11,valve inside ,and cap .The valve housing is made of brass in the dorm of a flanged tube that is mounted in the inner tube by means of a washer and a nut and sticks out through a hole in the wheel .Some tire valve housing are of comprise construction :the upper part is made of brass and the lower part ,of rubber that is vulcanized on to the inner tube .The valve inside is a check valve that opens to let air in the inner tube when an air closed ,spring pressure and air pressure inside the tube hold the valve .When the valve is closed ,spring pressure and air pressure inside the tube hold the valve in its seat .It includes core with a rubber ring ,a plunger pin ,and a spring .The valve inside is Screwed in the tire valve housing and is closed by the cap Screwed on the housing. To the construction of the driving and steerable wheels, each wheel comprises hub , disc with rim ,and tire with inner tube .The rim is welded to the disc and the disc is bolted to the hub . The driving wheel tires are of low-pressure type and have heavy tread bars for better traction. The driving wheel hub is keyed to axle shaft and is fixed in place by means of bolted-on insert with worm whose threads mesh with the rack teeth cut in the half axle .By turning the worm one can change the position of the wheel on the axle shaft to obtain the desired track width .Before doing this ,it is necessary to jack up the rear part of the tractor to clear the wheels of the ground and loosen the bolts that hold the inserts to the wheels hubs .Should this adjustment prove insufficient ,the track width can further be increased by placing the wheels with the concaves of their discs facing inwards. On some row-crop tractors ,the rear wheel discs are bolts to lugs welded on the wheel rims .In this case ,the crack width can be changed by bolts the discs in alternative positions to the lugs .Also the concave wheel discs may be used either with the concave facing inwards or outwards. 6 Trouble-free operation of automobiles and wheeled tractors largely depends on the condition of the tires. Therefore, during operation, one should adhere to following rules. Prevent fuel and, or oil from getting onto the tires. Cleans the tires regularly from dirt and remove all foreign articles, such as stones, form the treads. Do not apply brakes sharply, never start away form rest with a jerk, and avoid making sharp turns, for all this causes uneven wear of the tires. Do not allow excessive slipping of the driving wheels. When preparing your tractor or automobile for a long-term storage, jack up the wheels and put trestles under the axles or frame to relieve the tires. The service life of tires is expressed in terms of their mileage. For most bias (ordinary) truck tires, the guaranteed mileage amounts to 50000 km. Observing the above rules will help prolong the useful service life of tires. 7 驅(qū)動(dòng)橋 汽車的驅(qū)動(dòng)橋 驅(qū)動(dòng)橋是一個(gè)支撐車輛的十字交叉的軸，它可以驅(qū)動(dòng)車輪運(yùn)動(dòng)。驅(qū)動(dòng)橋包括：驅(qū)動(dòng)橋殼、主減速器傳動(dòng)軸、差速器、兩個(gè)半軸和末端傳動(dòng)裝置。 主減速器在傳動(dòng)中的功用是增大變速器傳 來的轉(zhuǎn)矩，憑借差速器把它傳遞給驅(qū)動(dòng)車輪。在汽車中主減速器傳動(dòng)軸把轉(zhuǎn)矩按正確的方向傳給驅(qū)動(dòng)輪，通常被叫做推進(jìn)器。 主減速器有單級(jí)和雙級(jí)兩種形式，前者包含一對(duì)齒輪，后者包含兩對(duì)齒輪。主動(dòng)小齒輪可以和軸做成一個(gè)整體，也可以做成分開的。從動(dòng)齒輪常做成齒圈形式，差速器殼可以用螺栓或鉚釘連接在齒圈上，主減速器的小齒輪和大齒輪可以做成螺旋齒，這樣可以在嚙合時(shí)減少噪音。 雙級(jí)主減速器包含一對(duì)錐齒輪和一對(duì)圓柱齒輪，主動(dòng)齒輪帶動(dòng)從動(dòng)錐齒輪旋轉(zhuǎn)而從動(dòng)錐齒輪和小圓柱齒輪通過中間軸連在一起從而使小圓柱齒輪轉(zhuǎn)動(dòng)，它與差速器殼固定在一起 的大圓柱齒輪嚙合，差速器殼的旋轉(zhuǎn)帶動(dòng)差速器運(yùn)動(dòng)并和軸承裝設(shè)構(gòu)成橋殼的一部分。 差速器在傳動(dòng)系中將轉(zhuǎn)矩分開分別驅(qū)動(dòng)兩側(cè)半軸，并且允許一側(cè)驅(qū)動(dòng)輪和另一側(cè)驅(qū)動(dòng)輪以不同的角速度運(yùn)動(dòng)。 差速器包括差速器殼、行星齒輪軸（十字軸），行星齒輪，側(cè)面齒輪即半軸齒輪。行星齒輪可以安裝在卡在差速器殼上的圓柱形十字軸上，并且保持與半軸齒輪的不斷嚙合。 當(dāng)汽車直線行駛和在水平路面上運(yùn)動(dòng)時(shí)，兩側(cè)驅(qū)動(dòng)輪將會(huì)遇到相同的滾動(dòng)阻力。在這種情況下，主減速器從動(dòng)齒輪帶動(dòng)差速器殼旋轉(zhuǎn)。當(dāng)差速器殼旋轉(zhuǎn)時(shí)差速器行星齒輪和十字軸也旋轉(zhuǎn)運(yùn)動(dòng)，因?yàn)榘胼S齒輪差 速器行星齒輪嚙合，半軸齒輪必須旋轉(zhuǎn)，導(dǎo)致半軸與兩側(cè)車輪也運(yùn)動(dòng)。當(dāng)每一個(gè)車輪承受的阻力相等時(shí)，差速器小齒輪不再旋轉(zhuǎn)，它們給半軸齒輪提供相等的轉(zhuǎn)矩且兩側(cè)車輪以一個(gè)相同的角速度旋轉(zhuǎn)。當(dāng)然，當(dāng)阻力不相等時(shí)，差速器行星齒輪既繞著差速器殼公轉(zhuǎn)又繞十字軸自轉(zhuǎn)，如果一側(cè)半軸不旋轉(zhuǎn)時(shí)，行星齒輪不會(huì)繞著固定不動(dòng)的半軸齒輪運(yùn) 8 動(dòng)，使另一側(cè)半軸齒輪以平常兩倍的速度旋轉(zhuǎn)。這樣你就明白差速器是怎么使一側(cè)齒輪轉(zhuǎn)速大于另一側(cè)的。 無論什么時(shí)候汽車轉(zhuǎn)彎行駛時(shí)，外側(cè)車輪總比內(nèi)側(cè)的車輪移過的距離大。內(nèi)側(cè)車輪會(huì)慢下來，而外側(cè)車輪則成比例地加速，由于 差速器在十字軸上自轉(zhuǎn)，且在速度慢的一側(cè)的半軸齒輪上滾動(dòng)，它將使外側(cè)車輪移動(dòng)的快一些。 半軸內(nèi)端用花鍵與差速器半軸齒輪連接，外端用凸緣與驅(qū)動(dòng)輪輪轂相連。載貨汽車采用全浮式半軸。這樣的半軸只承受轉(zhuǎn)矩作用。其余的負(fù)載由橋殼承擔(dān)，因?yàn)檩嗇炗砂惭b在橋殼上的軸支撐的。 輪式拖拉機(jī)的驅(qū)動(dòng)橋 一般的輪式拖拉機(jī)采用四輪驅(qū)動(dòng)的形式，它有兩個(gè)驅(qū)動(dòng)橋 前驅(qū)動(dòng)橋和后驅(qū)動(dòng)橋。除了橋殼之外，兩個(gè)橋的構(gòu)造很相似。每個(gè)驅(qū)動(dòng)橋都包括橋殼，主減速器，差速器和末端傳動(dòng)裝置。前后驅(qū)動(dòng)橋可以互換，且都包含一對(duì)螺旋錐齒輪。主減速器的主動(dòng)錐齒輪與軸做成 一體，并由兩對(duì)圓錐滾子軸承支撐，并用螺栓與差速器殼聯(lián)接。主動(dòng)錐齒輪凸緣外有螺紋孔與配套的螺釘，用于防止主動(dòng)錐齒輪在差速器殼作用下運(yùn)動(dòng)。關(guān)系到車軸中心線的主動(dòng)錐齒輪的位置是由裝在主動(dòng)錐齒輪后的調(diào)整墊片來調(diào)整的，裝在圓錐滾子軸承內(nèi)座圈的調(diào)整墊片用來調(diào)試安裝在主動(dòng)錐齒輪上的軸承的預(yù)緊力。齒輪軸的軸徑末端的凸緣采用一般的花鍵聯(lián)接。從動(dòng)錐齒輪用螺栓與差速器殼凸緣固定在一起。 差速器包括差速器殼、四個(gè)小行星齒輪，兩側(cè)半軸齒輪。差速器殼由兩部分構(gòu)成，它們用螺栓連接在一起，并由圓錐滾子軸承裝置支撐。軸承套外面的螺母用來避免 齒圈和主動(dòng)錐齒輪發(fā)生運(yùn)動(dòng)干涉，使它們正確嚙合，并調(diào)整軸承的預(yù)緊力。 焊在橋殼兩端頂部的是彈簧緩沖器，每個(gè)橋殼上都有注油孔，并用油塞塞住。每個(gè)橋殼都有一個(gè)通風(fēng)孔。橋殼內(nèi)的旋轉(zhuǎn)運(yùn)動(dòng)部件都涂有潤(rùn)滑劑。 在本書之中所有靠末端傳動(dòng)提供動(dòng)力的拖拉機(jī)與汽車考慮的地方有所不同?？磕┒藗鲃?dòng)的一般用途的輪式拖拉機(jī)有的裝有輪邊減速器。 當(dāng)傳來的轉(zhuǎn)矩驅(qū)動(dòng)車輪運(yùn)動(dòng)時(shí)，輪邊減速器也可以增大扭矩。這些像行星般運(yùn)動(dòng)的減速齒輪裝置包括太陽輪、行星齒輪、行星架、齒圈和減速器殼。 9 太陽輪用花鍵聯(lián)結(jié)在半軸外側(cè)的末端并且用鎖緊螺母擰緊固定。半軸的另 一端則用花鍵聯(lián)結(jié)著半軸齒輪。圓柱行星齒輪分別與太陽輪和齒圈嚙合，且繞裝在行星齒輪軸上的滾子軸承自轉(zhuǎn)，行星齒輪軸安裝在行星架上，行星架用螺栓和螺母固定在減速器殼上。減速器殼上的凸緣，制動(dòng)鼓，輪轂，用螺栓固定在一起，行星架，