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A shaft is a cylindrical object that passes through the middle of a bearing, wheel, or gear, but there are also a few square shaped objects. A shaft is a mechanical component that supports rotating parts and rotates with them to transmit motion, torque, or bending moment. Generally, it is in the shape of a metal circular rod, and each segment can have different diameters. The rotating parts in the machine are installed on the shaft.
There are three common types of shafts: crankshaft, straight shaft, and flexible shaft.
Straight shafts can also be divided into: ① rotating shafts, which bear both bending moment and torque during operation, and are common shafts in machinery, such as shafts in various reducers. ② Mandrels are used to support rotating parts that only bear bending moments without transmitting torque. Some mandrels rotate, such as the shafts of railway vehicles, while others do not, such as the shafts that support pulleys The transmission shaft is mainly used to transmit torque without bearing bending moments, such as the long beam shaft in the crane moving mechanism and the driving shaft of automobiles. The material of the shaft is mainly carbon steel or alloy steel, and can also be ductile iron or alloy cast iron. The working ability of a shaft generally depends on its strength and stiffness, and at high speeds it also depends on its vibration stability.