| 摘要 |
A flat wave-motion gear (1) which has an input shaft (4) supported rotatably at both end portions thereof between first and second end plates (2, 3). A wave-motion gear mechanism is incorporated between these end plates (2, 3), and a cross roller bearing (8) is provided on an outer circumferential side of the wave-motion gear mechanism. The wave-motion gear mechanism comprises a rigid internal gear (5), a silk hat-shaped flexible external gear (6) provided on the inner side of the internal gear, and an intermittent driving force generator (7) provided on the inner side of the external gear (6). An annular boss (64) of the flexible external gear is held between an outer race (81) of the cross roller bearing (8) and the second end plate (3), whereby these three members are fastened to one another. The rigid internal gear (5) is held between an inner race (82) of the cross roller bearing (8) and the first end plate (2) whereby these three members are fastened to one another. The input shaft (4) may comprise a hollow shaft. Owing to the employment of such a structure, the apparatus as a whole can be formed flat and to a length slightly larger than the axial length of the flexible external gear. Since the outer race of the cross roller bearing can be used also as a housing of the apparatus, the apparatus can be formed compactly by a reduced number of parts. <IMAGE> |
