| 摘要 |
A strain wave gearing is a negative deflection strain wave gearing. The tooth profile shape for the internally toothed gear is defined by using a convex, basic tooth profile curve, which is a curve portion from an inflection point (A) to a bottom-part point (B) of a moving locus (Mc) of an externally toothed gear with regard to an internally toothed gear obtained by a rack meshing approximation. The tooth profile shape for the externally toothed gear at a principal cross section is defined by a concave, basic tooth profile curve, which is generated in the externally toothed gear by the convex, basic tooth profile curve of the internally toothed gear moving from an apex (C) to an inflection point (A) of the moving locus (Mc). Passing-type meshing that is effective in lubrication is established, and bending stress in the tooth-bottom rim of the externally toothed gear can be reduced. |
| 主权项 |
1. A passing-type-meshing negative deflection strain wave gearing, comprising:
a rigid internally toothed gear, a flexible externally toothed gear disposed inside the internally toothed gear, and a wave generator disposed inside the externally toothed gear, wherein the externally toothed gear is ellipsoidally flexed by the wave generator, and external teeth of the ellipsoidally flexed externally toothed gear mesh with internal teeth of the internally toothed gear on both major-axis-direction ends of the externally toothed gear; the internally toothed gear and the externally toothed gear prior to ellipsoidal deformation are both spur gears having module m; a number of teeth of the externally toothed gear is 2n fewer than a number of teeth of the internally toothed gear, where n is a positive integer; a flexing amount relative to a rim-neutral circle prior to flexing is 2κmn, where κ is a deflection coefficient, at a position on a major axis of an ellipsoidal rim-neutral curve of a root rim of the externally toothed gear; the external teeth have a negative deflection tooth profile in which the deflection coefficient κ satisfies 0<κ<1; a movement locus of the external teeth relative to the internal teeth following a rotation of the wave generator is approximated by a movement locus obtained when meshing of the external teeth and the internal teeth is approximated by a rack; a tooth profile shape of the internal teeth on an axis-perpendicular cross section is defined by a convex, basic tooth profile curve; the convex, basic tooth profile curve is a curve having a range from an inflection point in the movement locus to the bottom part in the movement locus; a tooth profile shape of the external teeth on an axis-perpendicular cross section is defined by a concave, basic tooth profile curve; and the concave, basic tooth profile curve is a generation curve, the generation curve being generated by moving the tooth profile of the internal teeth defined by the convex, basic tooth profile curve, from the apex of the movement locus to the inflection point thereof. |
