Patent ID: 6845689

Claim:
A silk hat shaped wave gear device comprising: a circular rigid internal gear; a flexible external gear disposed inside the rigid internal gear; and a wave generator disposed inside the flexible external gear for flexing the external gear radially to engage partially with the internal gear and for moving engaged portions of these gears along a circumferential direction, wherein the flexible external gear is of a silk hat shape which comprises an annular body, external teeth formed on an outer circumferential portion of a first opening of the body, a circular diaphragm connected to a second opening portion of the body, and a circular boss connected to an outer circumferential end of the diaphragm, and the wave generator is fitted into a portion of the body where the external teeth are formed, and wherein a shape of a connected portion of the diaphragm and the body is defined so that the wave generator can easily be inserted into the body from the second opening of the body.