【作者】 江云；

【导师】 孙涛；

【作者基本信息】 哈尔滨工业大学 ， 机械制造及其自动化， 2011， 硕士

【摘要】 超精密加工设备是发展超精密加工技术的必要手段,国内外学者对超精密机床的静态特性、动态特性和热态特性进行了大量的研究,研究结果表明,在精密加工中,热变形引起的制造误差,占总制造误差的40%-70%,故对超精密机床进行热态特性分析尤为必要。本文研究了超精密金刚石车床的热态特性,为超精密金刚石车床的结构优化设计提供参考。采用空气静压轴承的主轴作为超精密金刚石车床最为关键的部件,其性能的好坏直接影响到超精密金刚石车床的加工精度。本文建立了空气静压轴承处气膜的导热模型,求解了不同转速下的气膜温升。通过推导得到空气静压轴承气隙对流散热系数,并通过经验公式计算得到主轴其他部位的对流散热系数,最后在大型有限元分析软件ANSYS中建立主轴和电机转子的有限元模型,对主轴在不同转速下的稳态温度场和热变形进行分析,绘制了主轴温度-转速曲线、热变形-转速曲线,最终验证主轴转速达到最高设计转速时不会出现主轴卡死的现象。作为超精密金刚石车床另一关键部件,液体静压导轨的静、动态特性对超精密金刚石车床的定位精度及加工精度有较大的影响,而采用直线电机驱动的液体静压导轨的热特性对机床加工精度的影响不容忽视。本章通过建立液体静压导轨的动导轨有限元模型,利用有限元分析软件ANSYS分析动导轨在不同工作环境下做不同运动时的热变形,提出减少液体静压导轨热变形的方法,避免导轨热变形对机床加工精度造成较大影响。本文还对所有内热源共同作用下超精密金刚石车床的热态特性进行分析,得到了整机的稳态温度场分布云图,同时得出主轴电机热量传导的路径;并对整机结构的热态热性进行评价。设计了主轴电机的水冷系统,并通过ANSYS仿真得到水冷系统的冷却效果。通过ANSYS仿真得到环境温度变化对加工精度的影响。最后讨论了主轴前端热伸长对零件表面加工质量的影响,并提出了针对本机床的热误差补偿的方案。更多还原

【Abstract】 Ultra-precision manufacture equipment is prerequisite for the development of Ultra-precision manufacture technology. Domestic and foreign scholars have done a lot of research on the static characteristics, dynamic characteristics and thermal characteristics on the ultra-precision machine tools. The results of the study show that 40%-70% of the machine tools’error is caused by is the thermal deformation of machine tools, so it has a great sense to analyse the thermal characteristics of the machine tools. In this paper, thermal characteristics of an ultra-precision diamond lathe are studied.The spindle adopting aerostatic bearing is the most important component of the ultra-precision diamond lathe.Thermal conductivity model of the gas film in the aerostatic bearing is established, and the temperature rise under different revolution is calculated in this paper. The heat convection coefficient in the air-gap of aerostatic bearing and on the other outside surfaces of the spindle are calculated. Finally the steady-state temperature field and thermal deformation under different revolution of spindle are analyzed by ANSYS, and temperature curve and thermal deformation curve under different spindle revolution are plot. The result shows that the stuck of spindle won’t happen when the revolution reaches the highest design revolution.To reduce the influence of thermal deformation of hydrostatic guide to the lathe, the finite model of moving guide of hydrostatic guide is established in this paper, then the thermal characteristics of moving guide under different working conditions are analyzed by using ANSYS. Simulation results show that the thermal deformation of moving guide is big when it is doing high-speed variational acceleration motion. Finally the methods of reducing thermal deformation of hydrostatic guide are proposed.This paper also analyzes the thermal characteristics of the ultra-precision diamond lathe under all internal heat source. The lathe’s steady-state temperature field is plot and the heat conduction paths from spindle motor are pointed out. Then the thermal characteristics of the whole structure of lathe is evaluated. A water cooling system of spindle system is designed. And the effect of water cooling system is simulated by ANSYS. How the environment temperature change affects the machining accuracy is also analyzed. Finally the influence of the spindle front-end extension to the microstructure surface processing is discussed, and an thermal error compensation scheme is proposed.更多还原