51吃瓜

1. Dimensional accuracy The journal is the main surface of shaft parts, which affects the rotation accuracy and working state of the shaft. The diameter accuracy of the journal is usually IT6 to 9 according to its application requirements, and the precision journal can reach IT5.

2. Geometrical shape accuracy The geometric shape accuracy (roundness, cylindricity) of the journal should generally be limited to the diameter common difference range. When the geometric shape accuracy requirements are high, the allowable tolerances can be specified separately on the part drawing.

3. The positional accuracy of Shenzhen mechanical parts processing mainly refers to the coaxiality of the matching journal of the assembly transmission part relative to the supporting journal of the assembly bearing, which is expressed by the radial circular beating of the matching journal to the supporting journal; according to the use requirements, the high-precision shaft is specified as 0.001~ 0.005mm, while the general precision shaft is 0.01~ 0.03mm. In addition, there are requirements for the coaxiality of the inner cylindrical surface and the verticality of the axial positioning end face and the axis line. 4. Surface roughness can vary depending on the surface working part of the part. For example, the surface roughness of the spindle bearing journal of an ordinary machine tool is Ra0.16 to 0.63um, and the surface roughness of the matching journal is Ra0.632.5um. With the increase of machine speed and the improvement of precision, the surface roughness value requirements of shaft parts will also become smaller and smaller.