床身蠕变下滚动直线导轨副的精度保持性研究

【作者】 徐斌；

【导师】 梁医；

【作者基本信息】 南京理工大学 ， 机械工程（专业学位）， 2017， 硕士

【摘要】 滚动直线导轨副是高档数控精密机床、磨床、组合加工机床等装备领域的核心功能部件。国内很多精密机床床身时效期短,机床床身在使用数年后将在内应力作用下发生蠕变。虽然机床刚开始使用时,其精度可以做到很高,但持续而缓慢的床身变形将引起导轨副的安装状态发生变化,导轨副内部的接触、磨损状态会不同于从前,造成机床精度不达标。研究床身蠕变对滚动直线导轨副的精度影响,具有重大意义。首先对床身蠕变下导轨副内部接触受力进行研究。一方面根据导轨副内部结构特点,基于Hertz接触理论对典型载荷下导轨副进行受力变形分析。另一方面结合常见机床导轨副安装布局方式,计算床身蠕变后导轨副内部接触的尺寸变化,推导出床身蠕变下导轨副内部钢球与滚道间的接触受力。其次,针对床身无蠕变的理想条件下导轨副精度保持性进行了试验研究。模拟实际工况,选取典型加载形式,测试运行过程中滑块顶面相对于导轨安装基准的平行度及导轨副的摩擦力,分析导轨副在不同跑合阶段的精度变化过程。在试验结束后,针对导轨副的运动特性和接触受力,对导轨副钢球和滚道接触表面特定区域进行微观形貌观测,对比精度保持性分析结果,研究导轨副磨损机理及其对精度的影响。最后,根据导轨副接触受力和磨损机理分析,基于Archard磨损理论,建立床身蠕变下导轨滚道表面磨损模型,结合上面的精度保持性试验数据进行模拟仿真验证。考虑外加载荷及滑块安装距离的影响,运用所建立的磨损模型,分析床身蠕变尺寸与导轨磨损量的关系。最后,结合理想条件下导轨副的精度变化规律及磨损模型,预测床身蠕变下导轨副的精度变化规律。更多还原

【Abstract】 Rolling linear guide is the core functional component of precision machine tools,grinders combined machine tools and other areas.The aging period of many domestic precision machine tool bed is shot,and the machine bed will undergo creep under internal stress after several years of use.Although the accuracy of the machine tool can be very high at the beginning of the machine,the mounting condition of the guide rail will change for the continuous and slow deformation of bed,which will cause the internal contact and wear stage to be different than before,at the same time,the machine precision is not up to standard.So it is of great significance to study the influence of bed creep on the accuracy of rolling linear guide pair.Firstly,the internal contact force of the linear rolling guide under creep of the bed was studied.On the one hand,according to the internal structure of the guide rail and Hertz theory,the force and deformation under typical load was analyzed.On the other hand,Combined with guide rail installation layout of the common machine tool,the size of the inner contact of the guide rail after creep of the bed was calculated,and then the contact force between the steel ball and the raceway was deduced.Then,the precision maintenance test of linear rolling guides in the same model from two domestic and foreign manufacturers was done.During the experiment,the linear guide was run under typical load condition.By measuring the parallelism of the slider top surface comparing to the installation benchmark and the friction of linear guide in different running distance,the accuracy change process of guide rail in different running stage was analyzed.After the end of the test,the specific surface between the ball and the roller was observed by SEM,then the wear mechanism was studied.By comparing the precision maintenance test results,the influence of the wear on the accuracy was researched.Moreover,the wear model was built under Archard theory,with test data which acquired in the precision maintenance test,the wear model of the rolling linear guide was compared and verified.The relationship between the bed creep dimension and the wear of the guide rail was analyzed by using the established wear model.Finally,the precision variation rule of linear guide under bed creep was predicted.更多还原