Analysis of Structural Characteristics and Technical Requirements of Machined Box Parts
1. Plane accuracy requirements
The design basis for machining box parts is generally flat. The design basis of each hole system and plane of the box body is G surface, H surface and P surface, wherein the G surface and the H surface are also the assembly reference of the box body. Therefore it has high flatness and high surface accuracy requirements.
2. Technical requirements for the hole system
A series of holes on the box with hole spacing and concentricity are called holes. In order to ensure the cooperation between the box hole and the bearing outer ring and the rotation accuracy of the shaft, the dimensional accuracy of the hole is IT7, and the geometric error of the hole is controlled within the dimensional tolerance range. In order to ensure the gear meshing precision, the dimensional accuracy between the hole axes, the parallelism between the hole axes, the coaxiality error of each hole on the same axis, and the perpendicularity error of the hole end face to the axis should have higher requirements.
3. Positional accuracy between hole and plane
The parallelism requirement should be specified between the main hole on the box and the mounting base of the box. The parallelism error of the center line of the spindle hole of the box body to the assembly base surface (G, H surface) is 0.04 mm.
The roughness of the important holes and the main surface will affect the mating properties or contact stiffness of the joint. The surface roughness of the main hole of the box body is 0.8 μm, and the surface roughness of the assembly base surface is 1.6 μm.