基于热力耦合下细长轴车削误差研究

Research on Turning Error of Slendering Shaft Based on Thermodynamic Coupling

摘要: 细长轴的长度比上直径的比率是大于20，在车削时，产生的热和力相互影响，引起残余应力的出现，导致材料表面塑性变形，影响尺寸精度，本文从理论、仿真、实验三个方面研究。引入热力耦合理论，细长轴在主轴夹紧、顶针顶紧辅助跟刀架下车削时，受到的切削力主要表现为径向力F_p，车刀和细长轴摩擦产生的热主要集中在刀具上，可以把刀具看做热源。使用ABAQUS软件仿真，模拟了切削温度和切削力，得出切削力中径向力F_p起主要作用，车削时切削温度主要表现为刀具温度。仿真设定不同的切削三要素V_c、a_p、f，采集细长轴车削时产生的径向力F_p、刀具温度T和残余应力实验数据，利用多元回归方程推导出残余应力误差预测公式。然后，搭建细长轴车削实验平台，选用YDC三向压电式测力仪和FLIRA20红外热像仪分别对车削时的径向力和刀具温度采集。得出不同切削三要素下刀具温度和径向力F_p的数值变化，对数据对比分析，验证了残余应力预测公式正确性。

Abstract: The ratio of the length to the diameter of the slender shaft is greater than 20. During turning, the generated heat and stress affect each other, resulting in the occurrence of residual stress, resulting in plastic deformation of the material surface, and affecting dimensional accuracy. This paper studies three aspects: theory, simulation, and experiment. The thermodynamic coupling theory is introduced. When the spindle is clamped and the thimble is pressed under the auxiliary tool rest, the cutting force is mainly manifested as the radial force F_p. The heat generated by the friction between the turning tool and the slender shaft is mainly concentrated on the tool, and the tool can be regarded as the heat source. The cutting temperature and cutting force were simulated by ABAQUS software, and it was concluded that the radial force F_p played a major role in the cutting force, and the cutting temperature was mainly represented as the tool temperature during turning. Three different cutting elements, V_c, a_p and f, were simulated and set. The experimental data of ra-dial force F_p, tool temperature T and residual stress produced during turning of thin shaft were collected. The prediction formula of residual stress error was derived by using multiple regression equations. Then, an experimental platform for turning thin shaft was built, and the radial force and tool temperature during turning were collected by YDC three-way piezoelectric dynamometer and FLIRA20 infrared thermal imager respectively. The numerical changes of tool temperature and radial force F_p under different cutting factors were obtained, and the correctness of residual stress prediction formula was verified by comparing and analyzing the data.