Research On Key Technologies Of Field Measurement Of Large Gear Machining Accuracy

Large gear as the most widely used transmission part in industrial heavy equipment,the measurement technology of large gear is directly related to the assembly accuracy and working reliability of the transmission system of heavy equipment.In recent years,with the rapid development of the heavy equipment manufacturing industry,the machining and manufacturing accuracy of large gear has gradually increased,and related industries have also put forward higher requirements for its measurement technology.Combined with the single-piece and small-batch production mode of large gear and the assembly conditions of heavy equipment,this paper adopted a field measurement technology which is different from laboratory measurement,designed a combined measurement network.The key technology of field measurement was studied on the basis of model establishment,simulation analysis and experimental verification.Laser tracker and flexible joint coordinate measuring arm were selected as measuring instruments,and a combined measuring network was designed for field measurement of large gear.Drawing on the leapfrog technology of the measuring arm,a spatial registration model between the measuring arm and the laser tracker was established.According to the characteristics of the measurement results of different measuring instruments,the target mirror was used as a common reference point for spatial registration,which solves the problem that the measuring points do not overlap in the process of spatial registration,the least squares method was used to solve the coordinate transformation matrix to realize the unification of the coordinates of the measuring data at different positions of the measuring arm.In addition,in order to ensure the accuracy of the final measurement results,a measurement accuracy improvement algorithm in the combined measurement network was designed.The multilateral measurement method was introduced into the field measurement technology of large gear,the angle measurement module with large error of the laser tracker was abandoned,the time-sharing multi-station measurement method of a single laser tracker was adopted,and the interferometric distance measurement result with high precision was used as the constraints,combined with the L-M optimization iterative algorithm,established a laser tracking multilateral measurement model,to realized the spatial coordinate solution of the common reference point.In the accuracy improvement algorithm,the introduction of the standard target mirror calibration plate can effectively solve the problem of determining the position parameters of the laser tracker at different positions in the laser tracking multilateral measurement model.By establishing the position parameter calibration model,the angle measurement module can be completely abandoned,the positioning accuracy of multilateral measurement can be improved,and the overall measurement accuracy can be improved finally.According to the actual field measurement conditions of the project,the large gear field measurement experiment and the field measurement accuracy improvement simulation experiment were designed.In the field measurement experiment,the measurement arm was used alone to complete the measurement of different gear teeth,and the average value of the single tooth pitch deviation was 0.0030 mm,while the single tooth pitch deviation after spatial registration reached 0.0907 mm,which proved that it is highly feasible to use the combined measurement network in field measurement technology,but the accuracy of measurement results needed to be improved.The simulation experiment including the accuracy improvement algorithm was further used to complete the verification,and the single tooth pitch deviation value of the large gear was 0.0092 mm,which could met the accuracy requirements of the corresponding dimensional parameter tolerance zone.The two groups of experiments showed that the established combined measurement network can complete the high-precision field measurement of large gear.The research provided a new solution for the field measurement of large gear.The established combined measurement network can well complete the field measurement and has a good accuracy improvement effect.It also has a certain applicability for field measurement of other large components.