| 摘要 |
In a principal section of the flexible external gear of a wave gear drive, a position away from the major axis of an elliptically shaped neutral line of the rim of the flexible external gear is defined as the center position of the teeth meshing, and theta is the angle of inclination of the tangent of that position with a point along the neutral line of the rim. The amount of flexing w of the principal section is defined according to the angle of inclination theta, the number of teeth zF of the flexible external gear, the number of teeth zC of the rigid internal gear, radius ro of the pitch circle of the flexible external gear, and the radius rn of the neutral curve of the rim prior to deformation. Thereby, the tangential direction common to both tooth profiles at the point of the contact between the tooth profiles of the two gears at the center position of the main meshing region within the principal section is made to coincide with the tangential direction at the said point of the contact of the curves of the linear generatrix of the neutral cylindrical plane of the rim projected on the principal section, enabling continuous contact between the two gears in the direction of the tooth trace. Using the tooth profile concerned makes it possible to alleviate stresses on the tooth bottom rim of the flexible external gear and the inner rolling contact surface of the wave generator, particularly those arising at points in the vicinity of the major axis.
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