Several types of constant velocity joints

The full name of constant angular velocity joint in English is constant velocity joint, which is a universal joint in which the rotational speed (angular velocity) of the driving shaft and the driven shaft are equal. In front-wheel-drive cars, the front axle is equipped with a constant velocity universal joint drive shaft (drive and steering).

The power of a front-wheel drive car must be directly transmitted to the front wheels from the powertrain composed of the engine, transmission and final drive. The front wheel is both a driving wheel and a steering wheel. The deflection point of view during steering is very large, and the maximum can reach more than 400.

At this time, the traditional universal universal joint shaft with a small deflection angle cannot be used. Because, in general, universal joints will fluctuate greatly in speed and torque when the deflection angle is large. Therefore, a constant velocity universal joint drive shaft with a large deflection angle and uniform angular velocity must be used.

The principle of constant velocity universal joint is similar to the principle of bevel gear meshing, because the direction of the force transmission point is always on the bisecting plane of the angle between the two shafts, thus ensuring constant velocity motion. The disadvantages of constant velocity universal joints are that the structure is relatively complex, the production process is fine, and the cost is high, so it cannot completely replace the general universal joint.

The appearance of constant velocity joints has greatly promoted the development of front-wheel drive cars and all-wheel drive cars.

Constant velocity universal joints generally have ball cage constant velocity universal joints, ball fork constant velocity universal joints and three-pin constant angular velocity universal joints. Commonly seen in general cars is a ball and cage type constant velocity universal joint.

Constant velocity universal joints for front-wheel drive are divided into two types: fixed at the wheel end and sliding at the differential end. The latter can slide elastically in the axial direction to compensate for changes in axial length.