| Fast and accurate measurement of gears is a key way to ensure gear quality.Gear measuring instruments based on line laser measurement methods have the advantages of high efficiency and full information,which is the focus of research on the next generation of gear measuring instruments.However,its measurement accuracy is lower than that of the contact gear measuring instrument.Therefore,it is important to carry out research on relevant accuracy theories and methods of this type of instruments.Line laser gear measuring instrument(LLGMI)is a gear measuring instrument currently being developed in China.It lacks in-depth and systematic research on accuracy design,error analysis,error compensation and other accuracy improvements of the overall and key components.In this paper,the geometric accuracy of LLGMI is improved by several stages:design,manufacture and commissioning,based on the structure and working principle of the instrument.The error homogenization mechanism of the multi-row ball bearing spindle(MBBS),the influence of geometric factors on the rotation accuracy,LLGMI error sensitive source identification and accuracy design,zero-point error modeling and compensation methods will be carried out to facilitate the upgrading of gear measuring instruments.The main research contents and conclusions are as follows:1)The error motion decomposition model of MBBS were established and the research on the elastic averaging principle was carried out.Firstly,based on the characteristics of the sensor adjustment mechanism in LLGMI being a quasi-static system,it is concluded that MBBS is the core component.Secondly,in view of the accuracy of MBBS,an error equalization model of MBBS based on Hertz elastic contact theory was established,and the error equalization coefficient reflecting the error equalization effect was defined.Again,by decomposing the spindle error motion into pure radial error motion and angular deflection error motion,three methods for the spindle error motion decomposition model are proposed,including full-points method,two-points method and least squares method.The numerical calculation results show that the rotation error of the two-points method is 6.75 times that of the full-points method,but the calculation results of the full-points method and the least squares method are similar.Therefore,the inherent unity between the elastic averaging effect and the mathematical optimization algorithm was established,and the elastic averaging principle of MBBS was revealed.Finally,experiments were carried out to show that the proposed error equalization model accurately solves the error equalization value,and the application of the elastic averaging principle can improve the rotation accuracy of MBBS by 7.86 times.2)The quantitative model of the geometric factors of rotation error of MBBS was established and research on influence rules was carried out.Firstly,a total error model including ball error,shaft and housing roundness errors and a rotation error geometric factor quantification model under the elastic averaging principle were established by analyzing the main geometric factors that affect the rotation accuracy of MBBS.Then,the rotation error was analyzed and the law affecting accuracy was studied.Numerical calculation results show that the diameter,number of rows and cage helix angle of the balls have little impact on the rotation error.The row number of balls,dimensional consistency error,interference,and roundness error of the shaft and housing have a greater impact on the rotation error.Among them,the impact of roundness error on the rotation error of the spindle is related to the amplitude and frequency of the roundness error.The impact of the roundness error of the shaft on the rotation error is greater than that of the housing.The rotation error period of the spindle caused by the roundness error of the housing is proportional to the angle between two adjacent rows of balls,while the spindle rotation error caused by the shaft roundness error has a double period.Secondly,experiments on the influence of geometric factors on rotation error were carried out to verify the above numerical calculation results,indicating that the established model can be used to propose strategies to improve the rotation accuracy of MBBS.At the same time,the results show that when the number of ball rows is 6 to 10,the interference is 3 to 8μm,and the ball accuracy grade is G5 or G10,the rotation accuracy of MBBS is better.3)The spatial error modeling method of LLGMI is proposed and the error sensitive sources were identified.Firstly,a spatial error modeling method using gear and sensor installation errors to replace geometric errors is proposed based on the characteristics of the sensor adjustment mechanism in LLGMI being a quasi-static system.It solves the cumbersome problems of traditional geometric error modeling and improves and simplifies the error transfer relationship.Secondly,the tooth surface deviation model,the single light height error model and the comprehensive error model were established by attributing each installation error to the incident light height error of the line laser.Thirdly,numerical calculation and experimental verification of the identification error-sensitive items were carried out based on the above model to provide a theoretical basis for the accuracy selection of key components in the design stage of LLGMI.The results show that the rotation angle error of the gear turntable and the tangential positioning error of the sensor have a greater impact on the measurement results,while the axial positioning error and pitch angle error of the sensor have a smaller impact.Finally,the accuracy design of LLGMI was completed based on the calculation results,which improved the measurement accuracy by 25.6%and reached the measurement accuracy requirements of level 6 gears.4)The zero-point error model of LLGMI was established and error compensation method research was studied.Firstly,in order to further improve the geometric accuracy of LLGMI during the debugging phase,an error compensation method based on zeropoint stability was proposed,and a zero-point error compensation model was established.Then the error compensation was performed based on the above model.Numerical calculation results show that the error value of the measurement point after compensation is reduced by about 5 times compared to before.Secondly,a confirmatory test of the zeropoint error model was carried out.The results show that compared with the measurement results of the Metrology Institute,the accuracy of the tooth surface deviation measured by LLGMI after compensation has been improved by 75%,and the accuracy has been improved by up to 85.86%.Moreover,the gear accuracy evaluation grade after compensation is consistent with the evaluation grade of the Metrology Institute,which illustrates the correctness and effectiveness of the zero-point error compensation model,and provides an effective way for improving the measurement accuracy of LLGMI.Figure[88]Table[21]Reference[256]... |
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