Constant Velocity Joint: Description and Operation

Halfshaft Joint

Front Drive Halfshaft - Sectional View









GENERAL
The CV joints are of the Birfield design. This design uses longitudinal, elliptical grooves, which retain 6 steel balls. The balls are further retained by a cage. The constant velocity is achieved by the position of the steel balls. If a centre line is drawn through the balls and the driven hub or differential shaft, the 2 centre lines always bisect each other at the angle of drive. This condition allows the rotational speed of the driven shaft to be passed to the driven hub or differential shaft with no loss of rotational speed regardless of the shaft angle. The CV joints are packed with grease, which is retained in the joint by a synthetic rubber gaiter. The gaiter is retained at each end by a metal clamp, which provides a water tight seal to prevent the ingress of dirt and moisture. The CV joints are retained on their respective shaft or tube by an internal snap ring. The snap rings are located in a groove on each shaft or tube end and locate in a mating groove in the CV
joint. The CV joints can be removed by a sharp tap with a soft mallet on the CV joint housing, which releases the snap ring from the groove.
The shaft is a sliding fit inside the outer tube, which allows for the small length changes which occur with articulation of the suspension. The shaft is located in a ball cage, which is retained inside the outer tube. The ball cage ensures that the shaft is held rigidly in the outer tube whilst allowing it to freely move in and out of the tube as necessary. A sealing plug is pressed into the outer tube and retains grease around the balls in the cage.
The inner CV joint shaft is splined and mates with splines in the front differential. A snap ring is located around the inner shaft and, when fitted in the differential, locates in a mating groove in the differential splined bore. The CV joint shaft is removed from the differential in a similar manner as removing a CV joint.