Development of Gear Finishing by a Compound Lapping Machine

Abstract

Compound gear lapping is to increase a certain degree of accuracy by lapping a pair of metal gears in mesh, and at the same time to improve roughness of tooth surface by lapping the metal gears in mesh with plastic gears at the shaft angle. The metal gears are lapping during traverse feeding in the place where oil coolant mixed with fine abrasive grains is spouted. The lapping test shows that only irregular profiles of the metal gears are removed and meshing noise is reduced. The test also finds the following; widely uniform tooth contacts are obtained by means of the plastic gears made of Polyacetal and fine adjustment of the shaft angle. Meshing noise is reduced to approximately 86 dB by selecting proper lapping conditions. The best tooth profile and the smallest meshing noise are achieved at the lapping time of 20 seconds. The profile is deteriorated and meshing noise becomes higher at a lapping time over 20 seconds.