For small and medium-sized motors, the most common types of shaft extensions are cylindrical and conical; Upon careful observation, it can be observed that motors for lifting and metallurgy generally use conical shaft extensions, while most other load motors use cylindrical shaft extensions. The diameter of the conical shaft extension section varies, so the torsional shear stress borne by the root of the shaft extension is much better than that of the straight shaft, and it is not easy to break the shaft due to metal fatigue caused by alternating stress. Therefore, it is suitable for mechanical equipment with large loads, high inertia, and frequent forward and reverse rotation. It is self-evident to choose conical shaft extension for lifting and metallurgical motors. The motors commonly used in lifting and metallurgical equipment, such as the YZ, YZR, and YZP series, mostly use conical shaft extensions. Compared
