? (1) Inner hole
The inner hole is the main surface of the bearing seat for support and positioning, and it is matched with the bearing outer ring. The dimensional accuracy of the diameter of the inner hole is generally 7 levels, and the accuracy of the high precision is generally 6 levels. The shape accuracy of the inner hole is generally controlled within the aperture tolerance range. For the bearing seat with high precision requirements, the shape tolerance is controlled at 1/3~1/2 of the aperture tolerance. In addition to cylindricity and coaxiality, the requirements for the straightness of the hole axis should also be considered. In order to ensure the function of the parts and improve their wear resistance, the surface roughness of the inner hole is generally Ra3.2~Ra1.6.
(2) The distance from the axis line of the hole to the ground
Ensure that the base and the top cover are parallel and dimensional.
