Constant-velocity joint

A constant-velocity joint (also called a CV joint and homokinetic joint) is a mechanical coupling which allows the shafts to rotate freely (without an appreciable increase in friction or backlash) and compensates for the angle between the two shafts, within a certain range, to maintain the same velocity.

A common use of CV joints is in front-wheel drive vehicles, where they are used to transfer the engine's power to the wheels, even as the angle of the driveshaft varies due to the operation of the steering and suspension.