In the finite element analysis of the whole machine, the contact between parts has a great impact on the analysis results, so it is necessary to set the contact pair reasonably. The types of joint surfaces of special machine tools for variable hyperbolic arc tooth profile cylindrical gears are mainly divided into two types: one is the joint surface of guide rail and sliding block, and the other is the joint surface of two parts connected by bolts. In order to simulate the contact condition of the machine tool in the actual working state, the contact relationship between the guide rail and the sliding block is simulated with no separation unit, and the joint surfaces of bolt connection and other small parts are simulated with bonded unit.
The grid structure and density in finite element analysis will directly affect the accuracy of finite element calculation results. In addition, the degree of grid encryption will also increase CPU computing time and required memory. Therefore, in the ideal case, the mesh density should not change with the mesh encryption, that is, mesh independence. After actual inspection, the grid sizes of 1.5mm, 2mm, 8mm, 15mm and 25mm are determined respectively according to the size and complexity of each component.
Hexahedral dominant meshing is adopted for the bed and cutter head, and tetrahedral Rons is adopted for other parts. At the same time, in order to improve the mesh quality, set the mesh smoothness to high; Set the grid correlation center to fine; Set the adjacent cell transition to smooth transition; The final meshing results in unit 1069 956 and node 1806 071. After inspection, the average grid quality is 0 82, the aspect ratio is 1.95 and the warpage is 0.002 8, which can better meet the requirements of finite element solution. The meshing results of the whole machine are shown in the figure.