| 摘要 |
<p>A half of a tooth right-angled cross-sectional shape in a tooth bottom side area (10) of a tooth (7) divided at a tooth bottom center (P0) as a boundary is defined by a first involute portion (13) extending from the tooth bottom center (P0) toward a tooth surface (8), an arcuate portion (14) connected smoothly to an end portion of the first involute portion (13), a second involute portion (15) connected smoothly to an end portion of the arcuate portion (14), a third involute portion (16) connected smoothly to an end portion of the second involute portion (15), and a tooth surface connecting curved portion (17) connecting an end portion of the third involute portion (16) and the tooth surface (8) smoothly. Radii of curvature of the first involute portion (13), the arcuate portion (14), the second involute portion (15) and the third involute portion (16) are determined so that a stress variation width in a stress state of a so-called partly reverse state caused by a tensile stress and a compression stress generated in the tooth bottom side area of the tooth before and after the meshing of the tooth can be uniformized.</p> |
