| Numerical control machine is the "machine tool" of the equipment manufacturing industry.The technical level and product quality of machine tool industry is an important symbol of a country’s development level in equipment manufacturing industry.As the key component of CNC machine tool,the performance of dual ball screw driving linear guide feed unit directly determines the overall performance of CNC machine tool.Finding out the key factors that affect the dynamic performance of the dual ball screw driving linear guide feed unit,especially the stiffness characteristics,and improving the overall performance of CNC machine tools more efficiently,are the top priority of the manufacturing industry.In this paper,based on the Hertz contact theory,the dynamic model of dual ball screw driving linear guide feed unit is built by considering the influence of each joint surface of the feed unit.Based on the Hamilton principle and Lagrange equation,the differential equation of vibration of feed unit is deduced.Then taking the test-bed of dual ball screw driving linear guide feed unit for example,the method of combining theoretical analysis and calculation with examples is adopted.The axial contact stiffness of ball screw pair and bearing pair and the contact stiffness of linear guide are calculated respectively,By comparing with calculation results,we found that the contact stiffness of ball screw pair is the most important factor.Finally,taking the test-bed of dual ball screw driving linear guide feed unit for example,using the 3D drawing software Pro/E,the model of dual ball screw driving linear guide feed unit is established.the finite element modal analysis of feed unit under different contact stiffness of ball screw pair is carried out by the finite element analysis software Workbench.The natural frequency is solved and the conclusion is verified. |
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