(by speedkar99)

Here’s how a CV Axle works to turn your car’s wheels. The constant velocity axle links the rotational motion of the transmission to the hub and thus turns the car’s wheels. Generally, CV axles are used on the front of FWD or AWD cars on vehicles with independent suspension.

The main advantage of the CV axle is that it allows for a very high degree of articulation, while still rotating its input and output shafts at the same speed. This is ideal for the front wheels which move up and down with the suspension, and turn sideways to steer.

The inner CV joint consists of a sliding tripod housing, that allows the axle to extend or contract. Inside, a carrier with needle bearings holds 3 rollers that allow for a small degree of swing.

The carrier looks like a fidget spinner. The outer CV joint does not telescope, however it has a very large degree of articulation, which is needed near the steering axis. It consists of an inner bearing race, a carrier, and the outer race or housing. the bearings are allowed to pivot about the central axis, but cannot rotate – allowing for constant rotation to be transferred from the input to output. Rubber boots cover each CV joint and are typically packed with grease.

Interestingly, the grease types appear different for each joint. Boot failure is the major cause of worn CV axles, once dirt enters the system and causes excessive wear. This axle was disassembled from a 2001 Toyota Corolla and opened up to see what’s inside and how it works.