摘要 |
PROBLEM TO BE SOLVED: To provide a sun gear which has been proposed by noting that a Hertz contract stress at a meshing pitch point of tooth surfaces is reduced, and which is constituted of a free-form surface maximizing the minimum curvature radius of a tooth surface in the vicinity of a meshing pitch point.SOLUTION: A sun gear is characterized in that: the addendum side of a tooth surface 12 is formed of an involute-helicoid curve surface; a free-form surface formed of a cycloid-helicoid curve or an arcuate helicoid curve for maximizing a curvature radius is linked to the vicinity of a meshing pitch point P continuing to the curve surface; and the involute helicoid curve links to the dedendum side continuing to the free-form surface. |