According to the knowledge of mechanics, to make an object rotate, there must be a torque acting on the object. The outer wall of the rack bush is in contact with the inner hole of the rack, so the torque of the rack bush rotation acts on this contact surface during press-fitting, and the direction is along the direction of the rack bush rotation. According to this analysis, the following two factors will cause the frame bushing to rotate.

First of all, during the processing of the inner hole of the cone crusher frame, due to the equipment or the operator, the inner hole roughness is too high, resulting in fine knife lines on the surface of the inner hole. The pressure on the bushing of the frame will deform the outer wall, and the outer wall will be embedded in the groove of the knife pattern in the inner hole of the frame. Because the knife pattern has a certain screw-in angle, under the action of pressure, along the screw-in direction will produce A force component that is the primary factor causing the frame bushing to rotate.
Secondly, in the process of press-fitting, theoretically, the applied pressure must act on the center of the frame bushing and the direction is parallel to the center, but in the actual press-fitting process, due to factors such as tooling, press placement and operators, etc. , will lead to a certain deviation between the applied pressure and the center of the frame bushing, forming a force that makes the frames.