| The ultra-precision master gear is used as gear substantial standard to transfer gear and its tester accuracy. Its manufacturing accuracy signifies the technological capability of the ultra-precision gear. The manufacturing level of ultra-precision gears in industrial small-batch production can reach class 2 (ISO 1328-1:1995, the same as follow) abroad, however, that of commercial domestic gear grinders and master gears can only reach class 3 at home. The overall manufacturing level of gear industry differs by class 1～2 at home and abroad. Aiming at machining principle, innovative mechanism and scientific processing of ultra-precision master gears' manufacturing, research work is conducted.According to the optimal forming of the involute and considering the easy refinement and high structural rigidity of the machine, the gear grinder with flat-faced wheel Y7125 is chosen as the object machine tool. As to the grinding wheel system, research work is done on the thermal expansion rule of the wheel spindle, the effect of cone-shaped error of the wheel working face on gear deviations, optimization of the wheel's outer edge width, gear-grinding characteristics and wear rule of the wheel. In addition, the wheel dresser is refined to ensure the working face accuracy and dressing quality of the wheel. As to the generating system, the effects of comprehensive eccentricity of the involute cam, the most precision part in the generating system, on gear profile diviations are analyzed. The measurement and regrinding on the involute cam are done in involute-template measuring and grinding devices that we designed. After refinement, the accuracy of the involute cam can meet the manufacturing requirements of class 1 gear profile. Two innovating measures to improve the indexing accuracy of the grinder, which are error compensation of the radial adjustable indexing plate and innovative design of the end-tooth automatic indexing system, are discussed. To improve the installment accuracy of the end-tooth indexing table, the dissertation employs the all-combination measuring method to the measurement and repair on the axial datum planes of the tables. Dynamic accuracy of Y7125 is preliminarily probed in the dissertation, the speed-changed gear-grinding process of the flat-faced wheel can suppress chatter in grinding process is validated and vibration testing on grinder's key parts are performed. In brief, the overall improvements of the accuracy of the grinder ensure the manufacturing accuracy of ultra-precision master gears.After improvement the accuracy of the grinding wheel system and the machine tool, studies on ultra-precision gear-grinding processing are indispensable. According to years of processing experience and new technical requirements, several scientific processing principles and operating methods of ultra-precision gear-grinding are concluded.Research on manufacturing principle of ultra-precision gears, innovative rebuilding and refinement of machine tools, and scientific gear-grinding processing is done by theoretical studies and scientific gear-grinding experiments. And ultra-precision medium-module master gears(m2 and m4)with class 1 and the ultra-precision gear shaper cutters and gear shaving cutters with accuracy higher than the current standards are developed, in which the former has an international leading technology. Research work on those independent innovations has a guiding role in the overall improvement of gear manufacturing technology in China.
|
PDF Full Text Request