On the processing technology of shaft core

Axle coreFunction, structural characteristics and technical requirements of parts

Axle coreParts are one of the typical parts often encountered in machines. It is mainly used to support transmission parts, transmit torque and bear load. The shaft section is a body of revolution section, the length of which is greater than the diameter, usually consisting of the outer cylindrical surface of the concentric shaft, the conical surface, the inner bore and the inner thread, and the corresponding end face. According to different structural shapes, shaft parts can be divided into optical axis, stepped shaft, hollow shaft and crankshaft.

Axle coreThe ratio of length to diameter is less5is called the minor axis and is greater20is called the elongated shaft, and most of the shaft is located between the two.

The shaft is supported by bearings, and the shaft segment that matches the bearing is called a journal. The journal is the assembly reference of the shaft. Their precision and surface quality are generally high. Their technical requirements are usually based on the main function and working conditions of the shaft. They usually have the following:

（12) Dimensional accuracy

In order to determine the position of the shaft, the journal supporting the bearing usually requires high dimensional accuracy (IT5~IT7). The dimensional accuracy of the journals of the assembled transmission parts is usually low (IT6~IT9）。

（22) Geometric accuracy

Axle coreThe geometric accuracy of the parts mainly refers to the roundness and cylindricity of the journal, the outer surface of the cone, the Morse taper hole, etc. Generally, tolerances should be limited to dimensional tolerances. For the inner and outer circular surfaces requiring high precision, the allowable deviation shall be marked on the drawing.

（32) Mutual position accuracy

Axle coreThe position accuracy requirements of the parts mainly depend on the position and function of the shaft in the machine. Generally, the coaxiality requirements of the bearing journals of the assembled transmission components should be ensured, otherwise the transmission accuracy of the transmission components (gears, etc.) will be affected and noise will be generated. For ordinary precision shafts, the radial runout of the supporting shaft section of the supporting shaft section is generally0.01~0.03mm, a high-precision axis (such as a spindle) is usually0.001~0.005mm.

（4) Surface roughness

Generally, the surface roughness of the shaft diameter matched with the transmission part isRa2.5~0.63μm, The surface roughness of the supporting shaft diameter matched with the bearing isRa0.63~0.16μm.