Gear mechanism

Abstract

A gear mechanism including an externally toothed circular gear having M circular teeth and rotating around a first central axis, and an externally toothed non-circular gear having N non-circular teeth and rotating around a second central axis separated by a predetermined distance D from the first central axis, wherein the circular teeth of the externally toothed circular gear have a circular gear tooth tip portion and a circular gear tooth side portion located on sides of the circular gear tooth tip portion and having a circular shape of radius r, the non-circular teeth of the externally toothed non-circular gear have a non-circular gear tooth tip portion and a non-circular gear tooth side portion located on the sides of the non-circular gear tooth tip portion and in contact with the circular gear tooth side portion, wherein the shape of at least a part of the non-circular gear tooth side portion is such that, when a virtual circle of radius D×N/(M+N) centered on the second central axis is taken as a fixed circle, a virtual circle of radius D×M/(M+N) centered on the first central axis is taken as a moving circle, and the center of the circular gear tooth side portion is taken as a drawing point, the epitrochoid curve drawn is an offset epitrochoid curve offset by a length r.

Dependencies are inferred from the claim text.