Shaft parts are a common type of parts, its structure is a rotating body, the length is generally larger than the diameter, in a variety of mechanical equipment, which are widely used to support the transmission parts, transfer torque and bear the load.
The processing of shaft parts follows certain rules as below:
1. Dimensional accuracy. Shaft parts of the main surface is often two categories: one is the inner ring of the bearing with the outer circular shaft neck, that is, supporting the shaft neck, used to determine the position of the shaft and support the shaft, dimensional accuracy requirements are higher, usually IT 5~IT7; The other kind is the shaft neck with various transmission parts, that is, with the shaft neck, its accuracy is slightly lower, often IT6~IT9.
2. Geometric shape accuracy. It mainly refers to the roundness and cylindricity of the important surface such as shaft neck surface, outer conical surface and taper hole. The error should be limited to the dimensional tolerance. For the precision axis, its geometric precision should be specified separately on the part drawing.
3. Mutual position accuracy. Including the inner and outer surface, the coaxiality of the important axial plane, the radial runout of the circle, the perpendicularity of the important end facing the axial line, the parallelism between the ends, etc.
4. Surface roughness. The machining surface of shaft has roughness requirement, which is generally determined according to the possibility and economy of machining. The supporting shaft neck is usually 0.2~1.6 microns, and the transmission fitting shaft neck is 0.4~3.2 microns.
