What Is a Universal Joint?

Universal joints are cross shape parts made of steel with a bearing cap at each end that allows the vehicle’s rigid driveshaft to connect to the transmission and rotate freely.

They are part of the system that enables the rotating crankshaft in a vehicle’s engine to transfer that rotating motion to the rear wheels in a rear-wheel-drive vehicle. Because they provide a flexible connection at the driveshaft’s ends, they allow the driveshaft to move up and down and at an angle to the engine as the vehicle encounters uneven road surfaces.

Typically, the u-joints connect to yokes that allow for a driveshaft’s fore-and-aft movement and the up-and-down movement for which the universal joints compensate. Without universal joints or some similar system, it would be impossible for a vehicle to have a suspension that offers any substantive wheel travel. The driveline would bind with every bump and pothole.

What is the Function of a Universal Joint ?

1. The universal joint is a component that realizes variable angle transmission of power between rotating shafts;
2. The universal joint is responsible for driving and steering between the front axle half shaft and the wheel;
3. The universal joint is a mechanism to realize variable angle power transmission and is used to change the position of the transmission shaft. It is the connecting piece of the universal transmission device of the automobile transmission system;
4. The combination of universal joint and transmission shaft is called universal joint transmission device. On a rear wheel drive vehicle with a front engine, a universal joint driver is installed between the transmission output shaft and the main drive axle reducer input shaft;
5. The front engine and front wheel drive vehicles omit the transmission shaft, and the universal joint is installed between the front axle half shafts, responsible for driving, steering and wheels;
6. The cross shaft rigid universal joint is widely used in automobiles;
7. The cross shaft rigid universal joint is simple in structure, reliable in operation, and allows a large angle of intersection between the two shafts connected. It is most widely used in automobiles.