FLEXING CONTACT TYPE GEARS OF NON-PROFILE-SHIFTED TWO-CIRCULAR-ARC COMPOSITE TOOTH PROFILE

摘要

In cup-shaped flexing contact gears (1), the respective tooth profiles of the rigid internal gear (2) and the cup-shaped flexible external gear (3) are each constructed such that the tooth face portion is formed of a straight line MA disposed in the vicinity of a datum point, a first convex circular arc AB smoothly connected thereto and a second convex circular arc BC smoothly connected to the first convex circular arc AB and having a radius of curvature larger than the first convex circular arc, while, the dedendum portion excluding the root is created by a standard rack consisting of a tooth profile formed by a curve point-symmetrical with respect to the datum point to the tooth profile at the tooth face or a curve obtained by correcting the above-mentioned curve. The curve defined by the above-described first and second convex circular arcs is an approximated curve of a similar curve obtained by subjecting to the conversion of similitude of 1/2 in the reduction ratio from the marginal point of intermeshing, which is selected on a composite curve to be described hereunder, this composite curve obtained by connecting a moving locus of teeth of the flexible external gear in a section of rotation in the vicinity of the end portion of the tooth trace on the side of a diaphragm to an envelope of moving loci obtained by overlapping on one plane of rotation the moving loci obtained by rack approximation of the external gear to the rigid internal gear in sections of rotation at the respective positions in the direction of tooth trace of the cup-shaped flexible external gear.