| 摘要 |
A worm gear mechanism (44) comprises a worm (70) and a worm wheel (80) meshed with the worm. In the teeth of a hob (90) used for the gear cutting of the worm wheel, at least the addendum surfaces (91c) are formed into arcuate shapes. The radial centers (93) of the arcs of the addendum surfaces are positioned nearer to a center line (WL′) of the hob than a pitch line (94) of the hob. The worm wheel is cut into a gear by the hob. The worm is formed into the same shape as the hob. The recess meshing length (L) of the worm gear mechanism is designed to be greater than the recess meshing length (Llim) of a conventional worm gear mechanism. |
