1. PRESENTATION ONREAR AXLE DRIVEANDREAR AXLE SHAFTS

2. TO : UDAY RAJ SIR BY NAWAL KISHORE BABUL 100109034 NEELESH MAHESHWARI100109035 PRAYAS NAVAL100109040 3. Forces on rear axle Wt. of the body Driving trust Torque reaction Side thrust 4. Automakers have developed a number of common methods oflocating a live axle First approachuses four trailing arms, two above theaxle, two below it, angled inward so that they resistlateral motion of the axle. 5. Another approach, used by Buick in the 1960 . uses two lower control arms and a single upper arm,mounted next to the differential, with a lateral track bar(a Panhard rod) or parallelogram linkage (Watts linkage) tolimit lateral motion. Both the three-link and four-linklayouts are reasonably effective, but the control arms andtrack bars make the rear suspension more complex, andthus more expensive to build . 6. THIRDOPTION IS 7. The Hotchkiss drive is a system of powertransmission . It was the dominant form of power transmissionfor front-engine, rear-wheel drive layout cars in the20th century 8. Simplest and most widely used type of rear axle drive . The spring besides taking weight of the body also take thetorque reaction , driving thrust and side thrust . propellar shaft is provied with two universal joints also asliding joint . The front end of the spring is fixed rigidly on the framewhile the rear end and is supported in the shackle . 9. In a Hotchkiss layout, the axle is suspended by a pair of longitudinallymounted semi-elliptical leaf springs, which serve tolocate the axle, as well as supporting the weight of thebody. The front portion of each spring functions like atrailing arm, transmitting drive torque to the body andresisting squat and axle tramp . 10. The rear portion of the spring acts as a leading arm,resisting wheel hop under braking. The stiffness of the springs also serves to resist lateralmotions. By making the springs perform multipleduties, Hotchkiss drive is very simple, and thus verycheap. Since it has few parts, its also very sturdy, which isuseful for heavy-duty vehicles like trucks. 11. The HOTCHKISS drive requires that the springs be rigidenough to withstand the twisting action (torque) of therear axle and the driving and braking forces that thesprings transmit to the frame. This type of drive iscommon to the equipment you will encounter in theNavy . 12. The differentiating characteristic of the Hotchkissdrive is the fact that it uses universaljoints at both ends of the driveshaft, which is notenclosed . The use of two universal joints, properly phased andwith parallel alignment of the drive and driven shafts,allows the use of simple cross-type universals . 13. Used in pick-up trucks and sport utility vehicles . 14. The design problem that the torque tube solves is howto get the traction forces generated by the wheels tothe car frame . The "torque tube" transmits this force by directlycoupling the axle differential to the transmission andtherefore propels the car forward by pushing on theengine and then through the engine mounts to the carframe . 15. In contrast, the Hotchkiss drive has the traction forcestransmitted to the car frame by using other suspensioncomponents such as leaf springs or trailing arms . A ball and socket type of joint called a "torque ball" isused at one end of the torque tube to allow relativemotion between the axle and transmission due tosuspension travel 16. Since the torque tube does not constrain the axle inthe lateral (side-to-side) direction a panhard rod isoften used for this purpose. The combination of the panhard rod and the torquetube allows the easy implementation of soft coilsprings in the rear to give good ride quality . 17. Torque tubes differ from the Hotchkiss design inthat a soliddrive shaft is enclosed in a hollow torque tube and rotates within a support bearing to preventwhipping 18. In both types of drive shafts the side thrust is taken theleaf springs . A separate member is employed to overcome thissituation : Panhard Rod it si fixed parallel to wheel axis with one end pivoted tothe axle and other to chassis frame 19. EXAMPLES OF THE TORQUETUBE American cars of the Ford brand up through 1948,which used the less expensive transverse springs thatcould not take the thrust. The C5 and C6 Chevrolet Corvette , Mercedes-BenzSLS AMG 20. Loads on rear axle shafts Shearing force due to wt. of vehicle . Bending moment on account of load applied throughspring seats . End thrust caused by side forces on account ofcornering , side wind Bending moment by end thrust and its reation offeredby tyres on ground Driving torque 21. Types of rear axle shaft Semi floating axle . Full floating axle . Three quarter floating type. 22. SEMI FLOATING AXLE With a semi-float axle, the axle shaft both carries theweight and transmits torque. The wheel is often bolted directly to the flange on theaxle. Semi-float axles are seen on cars and light duty trucks. Semi floats are more limited in capacity, but lighterand cheaper to manufacture. 23. FULL FLOATING AXLE the weight of the vehicle is supported by the axlehousing- more specifically, a bearing spindle attachedto the axle housing , and a set of bearings in a separatewheel hub. Torque is transmitted by a separate axle shaft thatcarries no weight. As commonly built, full-floaters are considerablyheavier, but also much stronger 24. SEMI FLOATING AXLE FULL FLOATING AXLE 25. THREE QUARTER FLOATINGTYPE 26. THREE QUARTER FLOATINGTYPE A three-quarter floating axle is the same as semi-floating, withone difference. The outer bearing is moved to the outside of theouter end of the axle tube, supporting a hub assembly via thebearings outer circumference edge. The splined or keyed shaft drives this hub, to which the wheel isattached.The shaft now supports minimal vehicle weight (so has muchreduced radial load), but still locates the wheel axially, andtransfers axial cornering loads (side thrust) to the axle innerbearing.