万向节即万向接头是实现变角度动力传递的机件，用于需要改变传动轴线方向的位置，它是汽车驱动系统的万向传动装置的 “关节”部件。万向节与传动轴组合，称为万向节传动装置。
The universal joint is a mechanical part to realize variable angle power transmission. It is used to change the position of transmission axis direction. It is the "joint" part of universal transmission device of automobile drive system. The combination of universal joint and transmission shaft is called universal joint transmission device.
万向节一般位于传动轴的末端，起到连接传动轴和驱动桥、半轴，或传动轴之间的连接。在前置后驱汽车上要想将动力传到后驱动桥上，必须将变速器动力输出轴与驱动桥之间进行连接。考虑到汽车运行中路面不平产生跳动，会使变速器输出轴与驱动桥输入轴之间的夹角和距离产生变化，不能直接进行“硬连接”，要用一个“以变应变”的装置来解决这一个问题，因此就有了类似肢体关节作用的万向节。
The universal joint is generally located at the end of the transmission shaft to connect the transmission shaft with the drive axle, half shaft, or between the transmission shafts. In order to transfer the power to the rear drive axle on the front and rear drive vehicle, the transmission power output shaft must be connected with the drive axle. In view of the fact that the uneven road surface will cause the change of the angle and distance between the transmission output shaft and the drive axle input shaft, so it is not possible to make "hard connection" directly. A "strain changing" device should be used to solve this problem. Therefore, there is a universal joint similar to the function of limb joints.