| 摘要 |
PURPOSE:To enable compression deformation of a unhardened part and sufficient maintenance of fatigue strength of a dedendum, by casehardening the surface of a gear by leaving addendum part at the edge in a face width direction uncasehardened. CONSTITUTION:In a spur gear, the surface of an addendum part at both the edges of the same in a face width direction is left unhardened for a unhardened part 4, and on the other hand a hardened part 2 is formed by hardening the surface of a tooth other than the part 4 extending over its whole surface excluding a tooth crest. In this case, on the assumption that the tooth is cut off by about a plane section which passes through a point A which is located at a distance L of 5-15% of tooth width from the edge of the tooth on the addendum and a point B which is on a about pitch circle P on the edge of the tooth, a range of the part 4 is set up so that the part 4 becomes on the addendum side than the plane section. With this, compression deformation of the unhardened part 4 is made possible, and a partial hit of the teeth is lightened. |
