Research On Realization Method Of Pitch Accuracy Of Ultra-precision Master Gear

As the measure benchmark of high precision gear detector, the master gear is required to have high transmission accuracy, which is higher than the gear detected by 2-3 grade. With the development of mechanization in recent years, the demand for high-precision gears has been increased in all fields, and there is a high requirement of transmission accuracy for high-precision master gears. Therefore, it is significant to research ultra-precision master gears for promoting technological level of gear manufacturing industry of China.Pitch accuracy is the most important index for accuracy of gear transmission, which directly affects stability and exactitude of gear transmission. This paper mainly focuses on how to improve the pitch accuracy of ultra-precision master gear.The main factors affecting pitch accuracy of the processed gear are analyzed in the paper, including the geometric eccentricity from gear installation and the indexing accuracy and installation error of the indexing plate. Increasing accuracy of the indexing system is the key to solve problems. The main contents are as follows:1. Sine compensation method to improve the installation accuracy of indexing plate.According to indexing principle of gear grinding machine, the measurement device ofindexing plate was designed and built to measure its cumulative pitch deviation. Taking the example of z38 tooth indexing plate, the indexing accuracy of the installed indexing plate was improved by sine compensation method, and its cumulative pitch deviation reached 4.88μm. In theory, it is up to the precision requirement for the first-grade gear; the installation position of the indexing plate was determined, and pitch accuracy of the processed gear shaper cutter is up to AA-grade.2. End-tooth indexing method to improve indexing accuracy of indexing system.At present, end-tooth indexing plate is the highest accurate mechanical indexing device Based on the principle of end-tooth indexing, indexing system of Y7125 gear grinding machine was improved in this paper. End-tooth indexing plate was used to improve indexing accuracy of the indexing system, and furthermore increase pitch accuracy of the processed gear.The whole combination measurement platform was built to measure the indexing accuracy of end-tooth indexing plate in the free meshing state. Its indexing accuracy is 0.3 "±0.32", which is up to the requirement of pitch accuracy for first-grade gear theoretically; the effect of axial runout and radial migration of the end-tooth indexing plate during the installation process were discussed. Development successfully of end-tooth indexing system provides a guarantee for grinding 2-1 grade ultra -precision master gears.At last, the factors affecting pitch measurement accuracy of Marh891E Gear measurement center was analyzed; the hardware and the software of the ultra-precision gear total cumulative pitch error measurement device were improved, which perfected measurement system and increased the measurement efficiency and accuracy.