Drive shafts for cars with front wheel drive consist of the outboard fixed joint, the inboard constant velocity joint and the connecting shaft. They also include elements such as the anti-lock system ring and the torsion damper. The basic design of the outboard fixed ball joint, the constant velocity joint, dates from the 1930s.
In most cases the inboard CVJ takes the form of a slip joint to allow the drive shaft to follow the movements of the wheel suspension. At the front axle (leading axle) the outboard joint must transfer the torque effectively through a large angle (up to 52 degrees). At the rear axle the angles of the outboard joints are considerably smaller.
Constant velocity drive shafts are exposed to maximum stress all the time that the vehicle is in operation. Alongside the extremely significant displacement angles and translational movement, the joints and bellows must be able to withstand temperatures of between minus 40 and plus 120 °C as well as speeds of up to 2800 rpm. In order to transmit the required torque in all engine speed and velocity ranges with reliable constancy (ideally throughout the entire service life of the vehicle), all components must be maintenance-free.
Depreciation
To maximise their service lives, drive shafts must be inspected regularly at a specialist garage. Such inspections are carried out as part of the regular service checks prescribed by vehicle manufacturers. Another good time to check the condition of drive shafts is when switching from summer to winter tyres or vice versa.
The specialist checks that the drive shaft is seated firmly and is clean and that the sleeves are in good order. Damaged sleeves must be replaced immediately to prevent damage to the joint caused by dirt penetration or grease escaping. If sleeves are loose or worn, there is a risk that dirt or moisture will already have penetrated into the joint. If in doubt, both the damaged sleeve and the entire joint should be replaced for safety reasons.
