はすば歯車のトロコイド干渉が歯面強度に及ぼす影響（歯すじ誤差, クラウニング及び歯先修整の影響）

Abstract

It is of practical importance to accurately evaluate the influence of tooth surface deviation and modification on the tooth surface strength of transmission gears. In this study, gear surface fatigue endurance tests were carried out with pairs of helical gears having various helix deviation, crowning and tip relief. The results showed that some damages on the tooth surface occurred unexpectedly earlier under certain conditions of these tooth flanks than the fatigue life predicted with a conventional design method based on Herzian pressure on the tooth surface. After observations of the tooth surfaces, it was found that the damages were caused by trochoidal interference, and the influence of the trochoidal interference on the occurrence of the damage was different in the meshing position, namely, the beginning of meshing and the end of meshing. The trochoidal interference in the beginning of meshing was much injurious to the occurrence of the damage. The tooth surface strength of transmission gears needs to be evaluated taking into consideration the occurrence of the damage caused by the trochoidal interference, because the conventional design method of tooth surface strength has a risk to overestimate the tooth surface strength. Therefore, the author discusses a new method combining the tooth surface temperature with the Herzian pressure to predict the occurrence of the damage caused by the trochoidal interference for a practical gear design.