床身蠕变下滚动直线导轨副的精度保持性研究

发布时间：2018-03-20 05:05

本文选题：床身蠕变　切入点：滚动直线导轨副　出处：《南京理工大学》2017年硕士论文　论文类型：学位论文

【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。
[Abstract]:The rolling linear guide pair is the core functional component in the field of high-grade CNC precision machine tool, grinder, combined machine tool and so on. The machine bed will creep under the action of internal stress after several years of use. Although the accuracy of the machine tool can be very high when it is first used, the continuous and slow deformation of the bed will cause the installation state of the guide rail pair to change. The internal contact of the guideway pair will be different from the former, resulting in the accuracy of the machine tool not up to standard. The influence of bed creep on the accuracy of the rolling linear guide pair is studied. It is of great significance. First of all, the internal contact force of the guide rail pair under the creep of the bed is studied. On the one hand, according to the characteristics of the internal structure of the guide rail pair, Based on the Hertz contact theory, the deformation of the guideway pair under typical load is analyzed. On the other hand, the dimension change of the inner contact of the guideway pair after the creep of the bed is calculated in combination with the common installation and layout of the guideway pair of machine tools. The contact force between the steel ball and the raceway inside the guideway pair under the bed creep is deduced. Secondly, the precision retention of the guideway pair under the ideal condition of no creep in the bed is studied experimentally. The typical loading form is selected to simulate the actual working conditions. In the course of running, the parallelism of the top surface of the slider relative to the installation datum of the guide rail and the friction force of the guide rail pair are tested, and the process of accuracy variation of the guide rail pair in different running-in stages is analyzed. After the test, the motion characteristics and contact force of the guide rail pair are analyzed. The microscopic morphology of the contact surface of the guide rail pair steel ball and raceway was observed, and the wear mechanism of the guide rail pair and its influence on the precision were studied by comparing the results of the precision retention analysis. Finally, according to the contact force and wear mechanism of the guide rail pair, the wear mechanism of the guide rail pair was analyzed. Based on Archard's wear theory, the surface wear model of guide rail raceway under bed creep is established, and simulated and verified by combining the above precision retention test data. Considering the influence of external load and the installation distance of slider, the established wear model is used. The relationship between the creep size of the bed and the wear quantity of the guideway is analyzed. Finally, combining with the law of precision variation and the wear model of the guideway pair under ideal conditions, the variation law of the precision of the guideway pair under the bed creep is predicted.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG502.3

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