借助弹性力学中的赫兹接触理论,分析计算直线滚动导轨的线刚度、滚珠丝杠副和角接触球轴承的轴向刚度,建立带滚珠丝杠副的机床直线导轨结合部的动力学特性理论模型,开发了计算软件;以一款立式加工中心为研究对象,分析计算带滚珠丝杠副直线导轨结合部动态刚度,着重讨论工作载荷对结合部动态刚度的影响规律,基于有限元法分析含结合部动态参数的加工中心整机动态特性。研究结果不仅突破了目前机床直线导轨结合部刚度模型不考虑滚珠丝杠副之缺陷,而且与传统的参数识别法和有限元法相比,具有物理概念清晰、计算过程简单等特点。
A dynamic model of linear guideway joint with ball screw is built by means of the linear stiffness of linear rolling guideway and the axial stiffness of ball screw and angular contact ball bearing, which can be calculated by using the Hertz Contact Theory of elastic mechanics, and related computer program for calculating the contact stiffness is developed. A vertical machining centre is selected as an example, the effect of cutting load on the dynamic stiffness of joint part is analyzed, and the dynamic characteristics of the entire machine tool with the joint stiffness considered are also discussed on the basis of finite element method. The analytical results show that it can not only overcome the shortcoming of the conventional method in without considering the effect of ball screw pair, but also appear clarity in physical concept and simplification in computation.