Analysis Of The Motion Accuracy Of The Worktable With Linear Rolling Guide

The forward design of geometric accuracy and assembly process optimization for gear measurement centers is one of the cutting-edge common technologies in the manufacturing field.As the core component of gear measurement centers,the rolling linear guide pair’s workbench motion accuracy is mainly affected by the manufacturing accuracy and assembly process of the components.The study of the error equalization mechanism between the guide rail installation base surface and the motion pair is the core of geometric accuracy design and assembly process optimization for rolling linear guide pairs.This paper focuses on studying the mechanism of motion error formation of the workbench during the assembly process of the rolling linear guide rail pair.Considering the constraint effect of multi slider co-planar constraints,an error mapping model between the guide rail installation base and the motion pair is constructed.Through a combination of simulation and experiment,the evolution law of the error equalization ratio coefficient of the guide rail pair under the effect of co-planar error is studied,To lay a theoretical foundation for the forward design of geometric accuracy and optimization of assembly process of gear measurement centers.A theoretical model for the motion error of a rolling linear guide pair workbench was constructed considering the co-planar over-constraint effect of multiple sliding blocks.Based on the Hertz contact theory,a contact analysis model for a single rolling element and a mapping relationship model between the straightness error of the guide rail and the bearing capacity of a single sliding block are constructed.The bearing capacity of a single sliding block is solved,and based on the force and torque balance equation of the four sliding block rolling linear guide rail system,a mapping model between the bearing capacity of the four sliding blocks and the pose error of the workbench is established.The multi point co-planar error equalization ratio coefficient is defined,Analyze the influencing factors of error equalization ratio and reveal the error equalization mechanism of the rolling linear guide pair system.A finite element model for the motion error of the rolling linear guide pair workbench was constructed considering the co-planar over-constraint effect of multiple sliders.A finite element model for static characteristics of a single slider was established based on the spring element method,and the correctness of the theoretical model for equivalent contact stiffness of rolling elements was verified through finite element simulation.Based on the principle of error equivalent allocation,a vector allocation model for guide rail straightness error and raceway surface error was established.The different error forms of guide rail straightness were mapped to the variation of spring length,and a finite element model for guide rail straightness error was established.The connection between the four sliders and the workbench view was regarded as an elastic connection,and a finite element model for workbench pose error under the effect of over-constrained error equalization was established.In response to the finite element simulation model established above,simulation analysis was conducted on key influencing factors,including the wavelength,phase,amplitude of random waveform error,geometric error morphology of arch error.A finite element comparative simulation model for a rolling linear guide pair system with/without over-constraint was established,and the influence of single influencing factors on the proportion of error equalization in both cases with/without over-constraint was verified.The simulation results show that the impact on the pose error of the workbench is in order of amplitude,wavelength,adjustment coefficient a,adjustment coefficient c,phase,and adjustment coefficient b.To verify the influence of error amplitude and wavelength on the error equalization ratio,an experimental platform for the rolling linear guide rail system was established.Nine sets of multi-point co-planar error equalization experiments were designed to detect the track surface error,slider straightness error,and workbench straightness error.The error equalization ratio was calculated and compared with the simulation results.The results show that the Z-axis straightness error equalization ratio of the four slider guide rail pair workbench can be reduced by a maximum of 45.11% compared to the three slider guide rail pair workbench,and the simulation results and experimental results of the Z-axis straightness error equalization ratio of the three slider guide rail pair and the four slider guide rail pair workbench do not exceed 22%,thus verifying the correctness of the finite element simulation model and theoretical analysis model.The simulation and experimental results also unanimously indicate that the influence of multi-point co-planar homogenization on the motion error of the rolling linear guide pair workbench cannot be ignored.