| Gears are the most important transmission mechanism,which have a long history and are widely used.The quality and accuracy of gears affect the efficiency,vibration and noise,motion accuracy and service life.The measurement and accuracy evaluation of gears are the main way to ensure the quality.Single gear deviations are important in gear evaluation.When measuring single gear deviations with gear measuring center,installation error makes the geometric center axis of the gear to be measured deviates from the rotating axis of the machine.This will affect the results of gear accuracy evaluation and even cause the change of gear evaluation grade.The influence of installation error in gear measurement was studied.This paper analysed the influence mechanism of installation error in gear measurement,described the evaluation method of tooth profile deviation and pitch deviation considering of installation error,realized the measurement of gear under the condition of inaccurate positioning.The coordinates of the base circle center and the value of installation error were obtained by reverse calculation of the upper transverse plane of the gear and the measuring points of tooth profile.The measuring points of tooth profile and pitch in machine coordinate system were transformed into workpiece coordinate system through coordinate system transformation.The evaluation of tooth profile deviation and pitch deviation was carried out according to ISO 1328-1:2013,thus the influence of installation error on the evaluation of tooth profile deviation and pitch deviations were corrected.Main contents include the following work:(1)The definition,symbol,cirtical points,tolerance allowable value and evaluation method in ISO 1328-1:2013 for the evaluation of tooth profile deviations and pitch deviations were studied,and the calculation method of evaluation range,data filtering and average tooth profile based on ISO 1328-1:2013 was given.(2)The mechanism of the influence of installation error on the evaluation of tooth profile and pitch deviations was analyzed;the processing model of installation error,the method of calculating the base circle center from the measuring points of tooth profile or pitch,and the evaluation method of tooth profile deviations and pitch deviations based on ISO 1328-1:2013 were established.The influence of measuring points of tooth profile on the results of reverse calculation of the base circle center is analyzed and the experimental scheme was designed.It mainly included the influence of the number of measuring points on the reverse calculation of the base circle center by a single involute,the influence of the number and position of involutes on the reverse calculation of the center of base circle by multiple involutes,and the influence of different initial values on the reverse calculation of the base circle center.(3)The software was designed based on MATLAB,and the installation error,the evaluation results and the calculation and display of the evaluation curves in the evaluation process of tooth profile and pitch deviation were realized.(4)The experimental verification was carried out,and the suggestions for selecting the measuring points of the tooth profiles were given when the the base circle center was reversed.The tests validated the evaluation method of tooth profile deviations and pitch deviations considering installation error.The results showed that the evaluation method of tooth profile and pitch deviations considering installation error can effectively eliminate the influence of installation error and could be suitable for gear measurement with certain installation error. |
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