Error Correction Technology For Gear Measuring Center

Gear measuring center is a kind of gear measuring instrument which can measure complex shape parts such as cylindrical gears,hobs,bevel gears,etc.It has the characteristics of compact structure,high measuring accuracy,many measuring parameters,wide application range,automatic measurement and fast measuring speed.The measuring accuracy of the gear measuring center is affected by many factors,such as the instrument error and the installation error when the gear is clamped.In this paper,through the mathematical modeling and analysis of the installation error of the gear measuring center,the correction algorithm of the installation error of the gear is put forward and verified by experiments.At the same time,the actual coordinates of the gear measuring center are measured by laser tracker and compared with the theoretical coordinates to realize the analysis and correction of the geometric error of the gear measuring center.Specific research contents are as follows:(1)The gear involute polar coordinate measurement method,normal polar coordinate measurement method and along the meshing line measurement method of the gear measuring center and their corresponding measurement principles are analyzed.According to the latest international standards,the method of evaluating gear quality grade by measuring data is discussed.(2)The installation error of gear and its influence on gear measurement are analyzed.Using the method of measuring the diameter jump of the gear shaft(or hole)by the gear measuring center,the measuring data of the installation error parameters of the gear are obtained.The method of calculating the error parameters of gear installation is discussed,and the ellipse fitting method is proposed to solve this problem.A gear measuring model is established to explain the measuring process of gears.On the basis of the model,the eccentricity error model and the yaw error model are established.Based on the model,the measurement and correction methods of gear profile,helix and pitch are put forward.(3)The experiment of measuring and solving the gear installation error is carried out,and the ellipse fitting method is used to solve the gear installation error parameters.The results show that there is a big error in the fitting results using single cross-section data,while the results using multi-section data are more stable.The data of tooth profile,helix and pitch deviation are processed by using the obtained gear installation error parameters and the gear installation yaw error model.The deviation curve after processing is consistent with the actual situation of the tooth surface,which verifies the correctness of the installation error correction algorithm.(4)Geometric error of gear measuring center is studied.The actual coordinates of gear measuring center are measured by laser tracker polygon method.The path of measurement is planned,and the geometric error vectors of each point in the path are used to interpolate the geometric errors of all points in the measuring center range of gears.Experiments show that the algorithm can accurately find the actual position of each point and provide a solution for the correction of geometric errors.