Research On On-machine Measuring And Pitch Deviation Compensation Technology Of Spiral Bevel Gears

Spiral bevel gears are the key components realizing transmission on the intersecting axes or staggered axis at the machinery manufacturing and widely used in automobiles, tractors, mining, metallurgy and other industries. Spiral bevel gears take advantages of smoothing transmission, strong carrying capacity compared with straight bevel gears. With the development of precision measuring technology at the machinery manufacturing, the technical foundation is laid for on-machine measuring of tooth profile errors of spiral bevel gears. At present, the CNC milling and grinding machines of Gleason and Klingelnberg corporation are equipped with on-machine measuring equipment achieving precision on-machine measuring of tooth profile errors and improving machining precision, however the research in this field is mainly for involute cylindrical gears in our country. The demand for low vibration, low noise, uniform load, etc is swelling with extension application for high-precision spiral bevel gears on transmission. In order to improve the overall level of spiral bevel gear of CNC machine equipment and processing technology, on-machine measuring of tooth profile errors and pitch deviation compensation technology of spiral bevel gears has been researched in this paper. The main research results are as follows:1、According to differential geometry, bevel gear meshing theory and machining principle of spiral bevel gears, the tooth surface mathematical model of spiral bevel gears was established. Referring to AGMA 2009-B01 standard, the tooth flank was discretized on the tooth surface rotating projection plane and the spatial coordinates and normal vector of the discrete points on theoretical tooth flank of spiral bevel gears was calculated applying optimization algorithms and coordinate transformation.2、Based on the machine structure and coordinates system of H350G CNC spiral bevel gear grinding machine, the spatial coordinates of the sphere center of probe in machine coordinates system was calibrated by gauging block. On-machine measuring of tooth profile errors for the gear and pinion and implementation method was determined according to the spatial coordinates and normal vector of the discrete points on theoretical tooth flank of spiral bevel gears. For the gear, the measuring manners of fixing workpiece was adopted. While the measuring manners of rotating workpiece should be adopted for the pinion considering large spiral angle of gear and the tooth surface curvature was changed obviously on the direction of tooth lengthwise.3、The reasons for pitch deviation compensation of spiral bevel gears was analyzed and the strategy of pitch deviation compensation was established. The model of pitch deviation compensation was established by axial compensation of wheel and rotational compensation of workpiece. According to the principle of measuring the pitch precision with gear measuring center and the measuring report of pitch deviation, the value of axial compensation of wheel and rotational compensation of workpiece was analyzed and calculated. The correctness of the pitch deviation compensation method is verified by comparing the measuring results of the pitch deviation compensation before and after and corresponding pitch precision.4、The software of on-machine measuring of tooth profile errors for the gear and pinion of spiral bevel gears was developed based on Siemens 840D CNC system. The correctness of the on-machine measuring method of tooth profile errors for the gear and pinion is verified by comparing the measuring results of the on-machine measuring system and gear measuring center.