hard steering, slippage, and tire wear each time the
vehicle turns a corner. Constant velocity joints
eliminate the pulsations because they are designed to
be used exclusively to connect the front axle shaft to
the driving wheels.
Basic operation of a CV joint is as follows:
The outboard CV joint is a fixed joint that
transfers rotating power from the axle shaft to
the hub assembly.
The inboard CV joint is a sliding joint that
functions as a slip joint in a drive shaft for rear-
wheel drive vehicles.
The constant velocity joints you will normally
encounter are the Rzeppa, Bendix-Weiss, and tripod
Rzeppa Constant Velocity (CV) Joint
The Rzeppa constant velocity (CV) joint is a ball-
bearing type in which the balls furnish the only points
Figure 5-7.Double-cardan universal joint.
of driving contact between the two halves of the
coupling. A Rzeppa CV joint consists of a star-shaped
inner race, several ball bearings, bearing cage, outer
race or housing, and a rubber boot (fig. 5-8).
The inner race (driving member) is splined to the
inner axle shaft. The outer race (driven member) is a
spherical housing that is an integral part of the outer
shaft; the balls and ball cage are fitted between the two
races. The close spherical fit between the three main
members supports the inner shaft whenever it is
required to slide in the inner race, relieving the balls of
any duty other than the transmission of power.
The movement of the balls is controlled by the ball
cage. The ball cage positions the balls in a plane at right
angles to the two shafts when the shafts are in the same
line. A pilot pin, located in the outer shaft, moves the
pilot and the ball cage by simple leverage in such a
manner that the angular movement of the cage and
balls is one half of the angular movement of the driven
shaft. For example, when the driven shaft is moved 20