| 摘要 |
An object of this invention is to provide a flexible meshing type gear having improved retaining force for lubricating oil film between gear surfaces. In a flexible meshing type gear (1), a flexture amount (w) in a radial direction of a cross section normal to a reference axis set at a predetermined position along a tooth trace of a flexible external gear (3) thereof is made a negative deflection flexture amount which is smaller than a normal flexture amount (wo), and a rigid internal gear (2) and the flexible external gear (3) are each constituted by a spur gear. The number of teeth of the flexible external gear (3) is made smaller by 2n (n is a positive integer) than that of the rigid internal gear (2). The working tooth profile of one of these two gears (2, 3) is formed into a convex curve, and the configuration thereof is made such that a portion (L1(O, A)) belonging to a convex relative to the other gear of the top portion of a moving path (L1) by a rack approximation drawn by the teeth thereof relative to the other gear on the cross section normal to the reference axis of the tooth trace is formed into a convex curve (L2(O, B)) which is similarity transformed using an extension ratio (.lambda.) with the apex of the moving path as an origin or a similarity curve thereof, while the working tooth profile of the other gear is formed into a concave curve, and the configuration thereof is also formed into a concave curve (L3(O, C)) resulting from similarity transforming of a portion of a moving path which is identical to that portion of the one of the two gears using an extension ratio (.lambda.+1) with the apex of the moving path as an origin, whereby the meshing between the two gears is made an over-running type meshing in which continuous contact is made possible at a cross section normal to the reference axis. |
