The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 09, 1997
Filed:
Dec. 22, 1995
Masataka Hashimoto, Tsu, JP;
Hong You Wang, Tsu, JP;
Teijin Seiko Co., Ltd., Osaka, JP;
Abstract
A planetary gear apparatus comprising an inner tooth gear having an inner peripheral portion formed with a plurality of inner teeth each in the form of a semi-circular cross-section shape and an outer tooth gear positioned within the inner tooth gear and having an outer peripheral portion formed with a plurality of outer teeth each in the form of a wave shape. The outer tooth gear has a center axis offset at an offset amount from the center axis of the inner tooth gear, and revolvable while being held in sliding and meshing contact with the inner tooth gear with the center axis of the outer tooth gear moving on a revolution orbit encircling and spaced from the center axis of the inner tooth gear at a distance equal to the offset amount. The outer teeth of the outer tooth gear have their respective tooth profiles each including deddendum and addendum portions, and a pair of tooth engaging portions each connected at its deddendum side end with the deddendum portion and at its addendum side end with the addendum portion. In the planetary gear apparatus, each of the tooth engaging portions of the tooth profiles has an epitrochoidal tooth surface extending on a theoretical epitrochoid curve having a central point coincident wit the center axis of the outer tooth gear, and the epitrochoidal tooth surfaces of the outer teeth are partly continually held in pressing contact with the inner teeth of the inner tooth gear even under the state that no load torque is applied to the outer tooth gear. The deddendum and addendum portions of the tooth profile of the outer tooth are closer to the center axis of the outer tooth gear than the theoretical epitrochoid cure, thereby making it possible to have the deddendum and addendum portions held out of contact with the inner teeth of the inner tooth gear even under the state that a certain load torque is exerted on the outer tooth gear.