This is a sectional drawing of the C. V. Axle, which enable to have a clear idea about the inner structure and the function of this kind of products.
On each end of the shaft is a ribbed rubber boot that covers a constant velocity joint (CV joint). The CV joint is the flexible coupling that allows the outer wheel to steer, and the shaft to follow the up and down motions of the suspension as the vehicle travels down the road.
The outboard CV joint (the one that connects to the drive wheel) typically has a much wider operating angle than the inboard CV joint that connects to the transaxle. This is because the outer joint may have to turn up to 50 degrees off center when the front wheels are steered. The inboard joint, by comparison, rarely sees an operating angle of more than about 20 degrees. Consequently, different types of joint designs may be used for the inner and outer joints