1. According to the requirements of the processing drawings, the dimensional tolerance requirements of the inner hole of the rack are strictly guaranteed. During the quality inspection and acceptance, the connection line between the measuring instrument and the measuring point of the inner hole should not be at the diameter of the inner hole, and the roundness and roundness of the inner hole must be guaranteed. Straightness, take multiple multi-position measurements, leave a certain margin before the inner hole is processed, and increase the process of the inner hole of the mill frame to ensure the roughness of the inner hole of the frame. The above-mentioned process should also be adopted for the circle to ensure the machining accuracy.

2. The inner hole of the rack and the outer circle of the rack bushing can also be designed in the form of segmented stepped holes, and the sizes of different segments are reduced from top to bottom, so that the rack can be reduced under the premise of ensuring the matching tolerance requirements. The press-fitting height of each section of the bushing indirectly reduces the rotation angle during press-fitting, and can also appropriately increase the width of the groove on the upper edge of the inner hole of the frame along the circumferential direction, which can ensure that the bushing of the rack remains stable even when it rotates at a certain angle. Allows bosses to fit into grooves.
3. When press-fitting, try to ensure that the point of action of the pressure is on the center line of the rack bushing. In the first third of the press-fitting, it is necessary to measure the distance between the rack bushing and the frame several times to ensure that it does not There will be a "rollover" situation. If the "rollover" tendency occurs, you can place a wooden block on the outer wall of the rack bushing and apply force from the side to correct it.