Two gear-grinding techniques to improve pitch deviations of ultra-precision gears

The ultra-precision master gear with high pitch accuracy has important applications in the calibration of high-precision gear measuring instruments or coordinate measuring machines and in military industries. In order to improve pitch deviations of ultra-precision gear, two gear-grinding techniques to improve pitch deviations of ultra-precision gear were proposed. First, based on the indexing plate system, the working principle of indexing plate and error transferring rules were discussed, and the technical approaches of decreasing the geometric eccentricity were proposed. Then according to the error interference principle, the offset-compensated technique and the neighbour-tooth translocation technique were proposed to improve the pitch machining accuracy of ultra-precision master gear. Finally, precision gear-grinding experiments were conducted by adopting the neighbour-tooth translocation technique based on offset-compensated technique. And the single pitch deviation fp of the test specimen is reduced from 1.06 to 0.63μm and the total cumulative pitch deviation Fp is reduced from 3.11 to 1.98μm with measurement uncertainty U95 = 0.33μm, which both reach the highest class (class 1 defining in ISO 1328-1:2013). The results show the efficiency and practicability of the two gear-grinding techniques to machine ultra-precision master gear.