It is very important to meet the technical requirements for precision hardware processing of equiaxed parts.
1、 Dimension accuracy, journal is the main surface of shaft parts, which affects the rotary accuracy and working state of the shaft. The diameter accuracy of journal is usually IT6~9 according to its application requirements, and the accuracy of journal can reach IT5.
The second is the geometric accuracy. The geometric accuracy of the journal (roundness and cylindricity) should generally be limited to the diameter tolerance. When the geometric accuracy is required to be high, the allowable tolerance can be specified separately on the part drawing.
Third, the location and accuracy of precision hardware processing manufacturers mainly refer to the coaxiality of the mating journal of the assembled transmission parts relative to the supporting journal of the assembled bearing, which is expressed by the radial circular runout of the mating journal to the supporting journal; According to the application requirements, the high-precision shaft is 0.001~0.005mm, and the general precision shaft is 0.01~0.03mm. In addition, the coaxiality of the inner cylinder surface and the perpendicularity of the axial positioning end face to the axis are also required.
Fourth, the surface roughness, according to different parts of the surface, can have different surface roughness values. For example, the surface roughness of the main shaft support journal of an ordinary machine tool is Ra0.16~0.63um, and the surface roughness of the matching journal is Ra0.632.5um. With the improvement of the speed and accuracy of the machine tool, the requirements for the surface roughness of shaft parts will become smaller and smaller.
