The purpose of circumferential fixation of parts on shaft is to transfer torque and prevent relative rotation between parts and shaft. In the design, the method of key and interference fit is often used for circumferential fixation

The purpose of the axial fixation of the parts on the shaft is to ensure that the parts have a definite axial position on the shaft, prevent the parts from axial movement and bear the axial force. Its fixing method often adopts shaft shoulder, shaft ring, conical surface, and shaft end retaining ring, shaft sleeve (sleeve), round nut, elastic retaining ring and other parts for axial fixation.