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1、Review 1:Whats the function of drive shaft and UJ?,To transmit the drive from the transmission mainshaft to the final drive pinion;To have some allowance for motion between the final drive and transmission.,1)The suspension connects the final drive assembly to the car body.The final drive moves up a
2、nd down in relation to the engine and transmission.A coupling is needed that permits movement between the final drive and transmission.The universal joints(U-joints)and sliding joints provide this coupling.,悬架连接着主减速器总成和车身。主减速器相对于发动机和变速器上下运动，这样就需要一个连接器来允许主减速器和变速器之间相对运动。万向节和滑动联轴节提供了这种连接作用,Review 2:Lis
3、t the types of UJ(Universal joints).,Non-constant Velocity Universal Joint,Constant Velocity Universal Joint,Near-constant Velocity Universal Joint,Cardan(Hookes)Universal Joint（十字轴式万向节）,Double Cardan Universal Joint（双联式万向节）,Rzeppa Universal Joint（球笼式万向节）,Tripod Universal Joint（三销轴式万向节）,Weiss Univer
4、sal Joint（球叉式万向节）,Flexible Universal Joint（挠性万向节）,2)Here two U-shaped pieces are placed perpendicular to one another and joined with a simple cross Fig.3-16.The U-shaped pieces are called yokes.The cross that connects them is called a spider.The arms that extend from the spider are called trunnions.
5、The two yokes are at a 90 angle to one another.Most cars have two universal joints,one at each end of the propeller shaft.,两个U形片垂直布置，通过十字叉连接在一起。U形片称为万向节叉，连接万向节叉的十字叉叫作十字轴，从十字轴延伸出的臂叫作耳轴，两个万向节叉成90布置。多数汽车采用两个万向节，在传动轴的每一端各有一个万向节。,3)A shaft which receives the drive from a cross type joint varies its speed
6、 during rotation;the greater the drive angle the greater the speed variation.A constant rotational speed can be restored by fitting a second joint in a way such that when the first joint increases its speed the second joint decreases its speed.,传动轴接收十字轴式万向节传来的动力，转动时其速度发生变化。传动角越大，速度变化越大。要实现等速，必须以某种方式
7、安装第二个万向节，这样第一个万向节使转速增大，第二个万向节就使转速减少。,Review 3:List the main parts of driving axle.,Review 3:Whats the function of Final Drive?,To reduce the speed of rotation,To redirect the line of drive,Single(reduction)final drive(单级主减速器),Drive pinion,Crown gear(ring gear),主动轮,从动轮,The final drive consists of a h
8、ypoid bevel gear drive.The geometry of the bevel drive pinion and of the crown wheel determines the final drive ratio.,Review 4:List the Gear Types of final drive.,Spur Gear（直齿圆柱齿轮）,Helical Gear（斜齿圆柱齿轮）,Bevel Gear（直齿圆锥齿轮）,Spiral/Hypoid Bevel Gear（斜齿/双曲面圆锥齿轮）,Worm Gear（蜗轮蜗杆）,4)The hypoid gear is in c
9、ommon use today due mainly to the fact that the offset pinion allows the propeller shaft to be set below,(for cars)or above,(for commercial vehicles)the crown wheel center.This gives either a reduction in the propeller shaft tunnel,which causes a bump in the vehicle floor,or in the case of a commerc
10、ial vehicle a reduction in the angle through which the universal joint has to operate.,现在的主减速器普遍使用准双曲面齿轮，这主要是因为主动锥齿轮的偏移允许轿车上传动轴布置得比从动锥齿轮低一些，而商用车上又允许布置得比从动锥齿轮高一些。这就使得传动轴管状盖板(它会导致汽车车身地板形成凸起)位置降低，或者使得商用车上万向节工作角度减小。,Review 5:List the types of Final Drive.,Single reduction final drive,Double reduction fi
11、nal drive,Thru-final Drive（贯通式主减速器）,Two Speed double reduction Final Drive（双速主减速器）,Planetary Wheel Reductor（行星齿轮式轮边减速器）,Wheel(Hub)Reductor（轮边减速器）,Spur Geared Wheel Reductor（圆柱齿轮式轮边减速器）,5)Large crown wheels reduce the ground clearance under the differential.In the case of pinion axles and planetary-h
12、ub reduction axles,the differential and the half-shafts can be made smaller by splitting the reduction.This makes it possible,even in the case of high power outputs,to achieve sufficient ground clearance of the vehicle.,从动锥齿轮尺寸大，就降低了汽车的离地间隙。如果采用圆柱齿轮式和行星齿轮式轮边减速器，通过两级减速的形式可极大减小差速器和半轴的尺寸。这样，汽车就可以获得足够大的
13、离地间隙，即使输出功率要求较大也可以。,6)Planetary gears are used mainly in final drives,rear-mounted splitter boxes and,above all,in automatic transmissions.The simplest form of planetary gear(the planetary-gear train)consists of sun gear,ring gear and arm with planet gears.Each of the three elements may act as drive
14、,output or may be at rest.Therefore,great variation is possible as regards the transmission ratio,ranging as far as a reversal of the direction of rotation.The parallel meshing of several gears under load permits a compact construction.,行星齿轮系主要应用在主减速器、后置副变速器和自动变速器上。最简单的行星齿轮系统由太阳轮、齿圈和行星轮组成。三部件中任意一个都可
15、作输入、输出或保持静止。这样，依照变速比的不同可得到较大的变速范围，汽车的倒行也能实现。承载齿轮的平行啮合使行星轮系结构较紧凑。,Review 6:Whats the function of Differential?,To allow the driving wheels rotate in different speeds.,side gear半轴齿轮,half shaft 半轴,Case 差速器壳,pinion gear行星齿轮,Pinion shaft行星齿轮轴,driven gear,side gear 半轴齿轮,pinion gear行星齿轮,7)When a vehicle is
16、 cornered the inner wheel moves through a shorter distance than the outer wheel.This means that the inner wheel must slow down and the outer wheel must speed up.During this period it is desirable that each driving wheel maintains its driving action.The differential performs these two tasks.,当汽车转弯时，内
17、侧车轮比外侧车轮行驶的距离要短，这说明内侧车轮比外侧车轮转得要慢。在此期间，维持每个驱动车轮的行驶状态是很重要的。这两个任务由差速器来完成。,Review 7:List the actions of Differential.,8)When the vehicle is travelling straight,the lever will divide the driving force equally and both discs will move the same amount.When the vehicle corners,the driving force will still b
18、e divided equally but the inner disc will now move through a smaller distance;this will cause the lever to pivot about its center which will prize forward the outer disc to give it a greater movement.This action shows that the torque applied to each driving wheel is always equal-hence the differenti
19、al is sometimes called a torque equalizer.,汽车直行时，杠杆平均分配驱动力，两个圆盘移动相同的距离。汽车转弯时驱动力仍然会平均分配，但是内侧圆盘移动的距离要小一些，这使得杠杆绕中心转动，推动外侧圆盘使之移动更大的距离。这个过程表明扭矩总是平均分配给每个驱动轮，因此差速器有时也叫做扭矩平衡装置。,Limited Slip Differential(LSD):（防滑式差速器）Locking Differential（强制锁止式差速器）Multi-disc Selflocking Differential（摩擦片式自锁差速器）,Review 8:Whats
20、the functions of Interaxial Differential?,To allow the driving axles rotate in different speeds.,Torsen Differential,Review 9:List the Drive Line of final drive.,Furcation Flange,Crown Wheel Gear,Pinion Bevel Gear,Differential Housing,Spider,Planet Gear,Axle Gear,Half Shafts,Driving Wheels,Drive Shaft and UJs,PART-TIME 4WD（分时四驱）FULL-TIME 4WD（全时四驱）REAL-TIME 4WD（恒时四驱）,Types of 4WD,Review 10:Whats the meaning of 4WD?,
