Planetary reduction gear having a molded ring gear
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsAkira Morishita, Kyoithi Okamoto, Toshihiko Gotoh, Yukio Kako, Takemi Arima
Life of this patent
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Abstract
A planetary reduction gear has an internally-toothed ring gear which is made of a molded synthetic resin. The ring gear has a rim formed in its outer periphery in which is formed a plurality of seats comprising through seats and non-piercing holes, the seats being provided at equal intervals around the periphery of the rim. The non-piercing seats extend only part way through the thickness of the rim. The provision of seats over the entire periphery of the rim causes sink marks which develop at the time of molding of the ring gear to act uniformly and deformation of the ring gear is prevented.
Claims4
A planetary reduction gear comprising:
- a sun gear;
- a planet gear which meshes with said sun gear;
- and
- an internally-toothed ring gear which surrounds said sun gear and said planet gear and meshes with said planet gear, said ring gear being formed of a molded synthetic resin and having a rim forced in its outer periphery and having a plurality of slots formed in said outer rim, said slots comprising through slots for bolts and non-piercing slots which extend only part way through the thickness of said rim, said slots being disposed at equal intervals around the periphery of said rim to cause sink marks developing during molding of the resin to act uniformly on the ring gear so that deformation of the ring gear during molding is prevented.
Dependencies are inferred from the claim text.