In front engine rear wheel drive or all-wheel drive the car, because the car suspension deformation in the process of movement, the main reducer input shaft drive shaft and transmission (or transfer case) often have relative movement between the output shaft, moreover, to effectively avoid some institutions or device, the inability to achieve linear transfer, must have a device to realize the dynamic normal pass, then a universal joint transmission. Universal joint drive must have the following characteristics:

1. Ensure that the relative positions of the connected two shafts can transfer power reliably when they change within the expected range;

2. Ensure that the connected two shafts can operate uniformly. The additional load, vibration and noise caused by the Angle of universal joint should be within the allowed range;

3. High transmission efficiency, long service life, simple structure, convenient manufacture and easy maintenance. For an automobile, since the output shaft of a cross shaft universal joint rotates at unequal speeds relative to the input shaft (with a certain included Angle), double universal joint (or multiple universal joints) must be adopted for this purpose, and the two universal joint forks connected with the drive shaft are arranged in the same plane, and the included Angle of the two universal joints is equal. This is very important. The Angle of universal joint should be reduced as far as possible in the design.