Research On The Precision Retention Of The Rolling Linear Guide Pair Under The Creep Of The Bed

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.