Main technical requirements
1. Dimensional Accuracy The journal is the main surface of the shaft component, which affects the rotation accuracy and working state of the shaft. The diameter accuracy of the journal is usually IT6~9 according to its application requirements, and the precision journal can reach IT5.
2, geometric accuracy Accuracy of the journal geometry (roundness, cylindricity), generally should be limited to the range of diameter tolerance points. When the geometrical accuracy is required to be high, the tolerances allowed are specified on the part drawing.
3. Positional accuracy mainly refers to the coaxiality of the matching journal of the assembly transmission member with respect to the bearing journal of the assembled bearing, which is usually expressed by the radial rounding of the supporting journal to the supporting journal; according to the requirements of use, The high-precision axis is 0.001 to 0.005 mm, and the general accuracy axis is 0.01 to 0.03 mm. In addition, there are coaxiality of the inner and outer cylindrical surfaces and the perpendicularity requirements of the axially positioned end faces and the axial line. 4. The surface roughness may have different surface roughness values depending on the surface working part of the part. For example, the surface roughness of the spindle of the common machine tool spindle is Ra0.16~0.63um, and the surface roughness of the matching journal is Ra0. 63 to 2.5 um, as the machine speed increases and the degree of precision increases, the surface roughness value requirements of the shaft parts will also become smaller and smaller.