精密磨床电主轴系统动态特性分析

发布时间：2018-05-14 22:15

本文选题：精密磨床 + 磨削精度　；参考：《东华大学》2017年硕士论文

【摘要】：随着汽车产业的发展,对凸轮轴的加工质量提出了更高的要求,凸轮轴磨削属于非圆磨削,不仅加工余量大、精度要求高而且材料比较难磨。因此,凸轮轴磨削技术在一定程度上制约着汽车产业的发展。凸轮轴磨削技术的关键在于精密磨床,而精密磨床的核心部件是电主轴系统,电主轴系统的动态性能直接决定了凸轮轴的磨削精度,动静压轴承作为主轴单元的重要支承部件,其油膜温升引起的主轴单元热变形很大程度上也影响着主轴回转精度。为了提高磨床的磨削精度、磨削效率和可靠性,本文对精密磨床电主轴系统做了如下研究:(1)根据磨床的技术参数及工况条件,计算了磨削的大小,对电主轴系统主要结构进行了设计计算,对电机进行了选型,确定了主轴单元的外径、内径、悬伸量以及支承跨距的大小,对轴承类型进行了选择并计算了轴承的刚度,分析了电主轴系统的机械结构及工作原理。(2)采用拉格朗日法建立电主轴系统的运动微分方程,应用ANSYS参数化设计语言建立了转子-轴承有限元模型,并对其进行了模态分析,获取主轴系统前五阶固有频率和模态振型,计算了主轴系统的临界转速,研究了不同边界支承对电主轴系统系统固有频率的影响。在模态分析的基础上进行了谐响应分析,计算了电主轴系统的动刚度,采用三支承结构对电主轴系统进行了改进,提高了电主轴系统的动态性能,并总结了提高电主轴系统动态性能的主要措施。(3)采用计算流体力学软件FLUENT对电主轴系统的前、后动静压轴承油膜温度场进行仿真,获得了前、后轴承油膜温度场分布云图。运用Workbench软件对主轴单元进行了热变形分析,获得了主轴单元前端部位的径向热变形量,研究了不同转数对主轴前端径向热变形的影响规律。(4)采用锤击法对精密磨床电主轴系统进行了试验模态分析,获得了主轴系统在单点激励下的频率响应函数,获得了电主轴系统的固有频率和阻尼比,验证有限元仿真结果的正确性。采用红外测温仪测量了电主轴系统运行过程中前、后动静压轴承实际温升,计算了实际主轴单元热变形量的大小,并与理论结果进行比较分析。
[Abstract]:With the development of automobile industry, the machining quality of camshaft is required higher. Camshaft grinding belongs to non-circular grinding, which not only has large machining allowance, but also requires high precision and difficult to grind materials. Therefore, camshaft grinding technology restricts the development of automobile industry to some extent. The key of camshaft grinding technology is precision grinding machine. The key component of precision grinding machine is motorized spindle system. The dynamic performance of motor spindle system directly determines the grinding accuracy of camshaft. The thermal deformation of spindle unit caused by oil film temperature rise also affects the spindle rotation accuracy to a great extent. In order to improve the grinding accuracy, grinding efficiency and reliability of the grinding machine, this paper has done the following research on the motorized spindle system of the precision grinder: (1) according to the technical parameters and operating conditions of the grinding machine, the size of the grinding is calculated. The main structure of the motorized spindle system is designed and calculated, the motor is selected, the outer diameter, inner diameter, overhang and support span of the spindle unit are determined, the bearing type is selected and the bearing stiffness is calculated. The mechanical structure and working principle of the motorized spindle system are analyzed. Lagrangian method is used to establish the differential equation of motion of the motorized spindle system. The finite element model of rotor-bearing is established by using ANSYS parametric design language, and the modal analysis is carried out. The first five natural frequencies and modal modes of the spindle system are obtained. The critical speed of the spindle system is calculated and the influence of different boundary supports on the natural frequency of the motorized spindle system is studied. On the basis of modal analysis, harmonic response analysis is carried out, the dynamic stiffness of motorized spindle system is calculated, and the dynamic performance of motorized spindle system is improved by adopting three-support structure. The main measures to improve the dynamic performance of the motorized spindle system are summarized in this paper. The main measures of improving the dynamic performance of the motorized spindle system are summarized. The simulation of the oil film temperature field of the motor spindle system with the computational fluid dynamics software FLUENT is carried out, and the distribution of the oil film temperature field of the front and rear bearings is obtained. The thermal deformation of the spindle unit is analyzed by using Workbench software, and the radial thermal deformation of the front end of the spindle unit is obtained. In this paper, the influence of different rotation numbers on radial thermal deformation of spindle front end is studied. (4) the experimental modal analysis of motorized spindle system of precision grinder is carried out by hammering method, and the frequency response function of spindle system under single point excitation is obtained. The natural frequency and damping ratio of the motorized spindle system are obtained to verify the correctness of the finite element simulation results. The actual temperature rise of the front and rear dynamic and static bearing during the operation of the motorized spindle system was measured by using the infrared thermometer. The magnitude of the thermal deformation of the actual spindle unit was calculated and compared with the theoretical results.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG580.23

【相似文献】