Research On Thermo-mechanical Coupling Characteristics Of Rolling Linear Guide

CNC machine tools are developing in the direction of high speed and high precision.As a guide part,the rolling linear guide is used more and more widely.The machining precision of guide rail plays a key role in the precision of machine tool.The mechanical properties,thermal properties,thermal coupling characteristics and other nonlinear factors of the guide have very important influence on the final accuracy of the guide,so the research on the influence of thermo mechanical coupling characteristics on the precision of the track is very meaningful.This paper takes THK company production of HSR series of linear rolling guide as the research object,study on the formation mechanism of the thermal coupling characteristics of rail,thermal theory analysis model and simulation model of a rail coupling characteristic have been established,analysis the results of temperature field and thermal deformation of rail.At last,we measured the temperature and thermal deformation of the guide rail.The experimental data were compared with the theoretical analysis and the simulation analysis results,and the correctness of the model was verified,which provided a theoretical basis for the thermal error compensation of the machine tool.The specific work is as follows:(1)The research status and latest progress of rolling linear guides at home and abroad in recent years are reviewed,including the research status of static and dynamic characteristics and thermal characteristics of rail,and the main contents and research methods of this paper are determined.(2)The force and movement of the ball in the bearing area of the guide rail and the friction characteristics caused by various motions are studied.Based on the Hertz theory,the contact characteristics between the ball and the slide block are studied,and the deformation formula of the guide in the contact area is derived.The slip,gyro and spin motion of the ball bearing in the guide rail bearing area are studied.The friction and wear mechanism of the slide is analyzed,and the relationship between the external force and the friction force is obtained.(3)The theoretical analysis model of the thermal coupling characteristics of the guide is established.On the basis of heat transfer and elastic mechanics theories,the means of heat transfer of the guide is analyzed,thermal boundary conditions and the coupling coefficients of the stress field and temperature field were calculated.The differential equation of the coupling heat conduction of the guide rail is established.The expressions of the dimensionless temperature field,displacement and thermal stress on the length and time of the guide rail are obtained.(4)The simulation analysis of the thermal coupling characteristics of the guide is completed.A finite element model of the rail using the finite element simulation software is established,The static analysis,static state analysis and transient analysis considering the moving of the heat source of guide rail are realized,and on the basis of this,the thermal mechanical coupling simulation analysis of the guide rail is realized,and the displacement and stress distribution results are obtained.The effect of thermo mechanical coupling characteristics on the guide rail is analyzed by comparing the results of the thermodynamic coupling analysis with the results of the displacement and stress distribution in the static analysis.(5)The experiment of measuring the temperature and thermal deformation of the guide rail was carried out.The experimental data of the temperature rise and deformation of the guide under the condition of working conditions are obtained.The variation of the temperature and deformation of the guide with time is analyzed.The correctness of the model is verified by comparing the experimental results with the results of theoretical analysis and simulation analysis.In this paper,the method of combining the establishment of theoretical analysis model,the establishment of simulation analysis model with the experiment is used to study the thermal coupling characteristics of linear rolling guide.The results of the temperature,displacement and thermal stress of the guide under the condition of working conditions are obtained.The correctness of the analysis model is verified by comparing the experimental results with the theoretical and simulation results,which provides a basis for further research on the thermal coupling characteristics of the guide rail,and provides data for the research of thermal error compensation of the machine tool.