The name of this driveline system is? Hotchkiss drive

Hotchkiss drive

The name of this driveline system is? 2-piece drive

2. Control torque reaction Discuss torque reaction

torque reaction

Extreme torque reaction

UJs allow for changes in the angle of the propshaft due to suspension travel

Sliding joint allow for changes in distance between components due to suspension travel

Why are centre bearings used on vehicles with a large distance between the gearbox and final drives? Long prop shafts require a centre bearing to avoid vibration due to whip. Describe the need for the sliding joint on the front of the propshaft. The sliding joint allows for any changes in length between the gearbox and final drive due to suspension travel When removing a propshaft it is good practice to mark a line across the sliding joint. Why is this so? To ensure correct realignment should the sliding joint become disconnected

Identify the types of universal joints and list the advantages and or disadvantages of each type.

Hookes type No advantages

Cross type joint (Hardy Spicer) developed from the Hooke type Compact, large drive angle, minimum power loss, operate at high speed

Cross type with rubber bushings Smooth drive take up. Wear rate very high

Layrub type No lubrication required. Allows for axial movement so no sliding joint required.

Doughnut rubber coupling As above/ larger design so more space under the car is required

Speed variation of Hooke-type UJs In this illustration a simple universal joint, often referred to as a Hooke’s or Spider joint, can be seen to have a major draw back. Rotating at an angle of 30 degrees the speed of shaft B varies in relation to shaft A. This is often referred to as changing angular velocity. If action was not taken to overcome this problem, vibration and surge at the wheels would be produced.

Two Joint Compensation Variations in angular velocity are cancelled out by fitting a similar joint to the other end of the shaft. The drive and driven shafts are also fitted parallel to each other to smooth out variations in rotating speeds and torque. The drive angle of each UJ must be the same

Correct Fitment Correct Incorrect Because of this it is vital that propeller shafts are fitted correctly. Propeller shaft ends must be marked so that they can be refitted in exactly the same location. If this is ignored vibration and noise will be the result. Phasing the UJs to ensure they operate in the same plane

Propeller Shaft Alignment Marks Alignment marks as illustrated should be added before disassembly.

Identify the components of the following drive assembly. FRONT WHEEL DRIVE

Drive shafts for front wheel drive systems can be solid as well as hollow depending on the manufacturer.

Constant velocity joints

Identify the components of a CV joint

Constant Velocity Joint - Birfield A Birfiled joint, sometimes known as a Rzeppa joint, has an inner race fitted into an outer race between which steel balls are held in position by a steel cage. Simple construction and the ability to transmit large torque through a considerable angle means this joint is a common feature of drive shafts fitted to front wheel drive vehicles. Because the intersecting point (0 in the illustration) of the driving and driven shafts and the centre (P in the illustration) of each ball bearing is constant this is a constant velocity joint. The rotational speeds of the drive and driven shafts are identical. The expression constant velocity is commonly abbreviated as C.V. and a joint of this type often referred to as a C.V. Joint. The joint is encased in a flexible boot to retain the appropriate lubricating grease.

Constant Velocity - Tripod Also known as a plunge joint This type of joint must be used to allow for the changes in the length of the driveshaft The Tripod joint has three trunnion shafts on which three rollers, which have roller bearings, run. An outer casing has a groove in which each of the rollers are located. A relatively inexpensive joint which usually has axial movement. The joint is encased in a flexible boot to retain the appropriate lubricating grease. Failure of drive shaft joints are usually preceded by failure of the flexible boot allowing the loss of lubricant and the ingress of road dirt.

Intermediate Shaft An illustration of an intermediate drive shaft fitted to maintain straight-line stability during acceleration.

Reasons for an Intermediate Shaft During sudden acceleration the front of a vehicle tends to rise up. If drive shafts of significantly different length are fitted, as in the top illustration, joint angle Ø1 will be much greater than Ø2. This will cause the wheel attached to the shortest drive shaft to attempt to ‘track or toe in’ further than the wheel attached to the longer drive shaft. This will cause the vehicle to veer toward the side with the longest drive shaft. To prevent this from occurring, by keeping joint angles and drive shaft length the same, an intermediate shaft is often fitted, as shown in the bottom illustration.