Universal Joints

Universal joint is a special type of mechanical connector that can achieve power transmission when the two axis lines do not coincide and there is an angle between them. This sophisticated device solves the angle deviation problem that traditional rigid couplings cannot overcome, providing greater flexibility for mechanical design. The basic function of a universal joint is to change the direction of power transmission while allowing the two connected shafts to swing relative to each other within a certain angle range, making it an indispensable component in complex transmission systems.

The core functions of universal joints are reflected in three aspects: transmitting torque, adapting to angle changes, and compensating for axial displacement. In the automotive drive system, the universal joint is known as the "joint" component of the universal transmission device, which enables the power generated by the engine to be smoothly transmitted to the wheels, ensuring uninterrupted power regardless of whether the vehicle is driving in a straight line or turning. According to the different structural forms, the universal joint allows the angle between the two axes to vary between 15 ° and 45 °, and some special designs can even achieve larger angles.

The basic working principle of universal joints is based on the mechanical kinematic principles of cross axis or ball cage structures. Taking the most common cross axis universal joint as an example, it combines a cross axis and two universal joint forks to enable the input shaft and output shaft to transmit rotational motion even in the presence of an angle. When the driving shaft rotates, the pivot action of the cross shaft drives the driven shaft to rotate, while allowing the angle between the two shafts to freely change within a certain range. This design, although simple, effectively solves the problem of power transmission when the axes do not coincide.

It is worth noting that traditional cross axis universal joints have an inherent characteristic when transmitting power: when there is an angle between the two shafts, the speed of the output shaft will fluctuate periodically, even if the input shaft rotates at a constant speed. This unequal velocity may cause vibration and noise, so in practical applications, engineers have developed various technologies to solve this problem, including the use of advanced designs such as dual universal joint arrangements and constant velocity universal joints.