The universal joint uses the characteristics of its mechanism to make the two shafts not on the same axis, and the two axes can be continuously rotated under the condition of the angle of the axis, and the torque and the movement can be reliably transmitted. The biggest feature of universal coupling is that its structure has large angular compensation capability, compact structure and high transmission efficiency. The angles of the two axes of different structural types of universal joints are different, generally between 5° and 45°.