| 摘要 |
<p>A knurled press-fitting portion (58) and an annular groove (59), which receives foreign matter and is formed to extend in a circumferential direction in front of the press-fitting portion (58) of a cylindrical protruding portion (57), are provided at an outer peripheral surface of the protruding portion (57) of an output shaft (23). A fitting portion (60), which is fitted to a coupling tube (67) by press-fitting, is formed at an outer periphery of an opening end of the protruding portion (57). An outer peripheral surface of the cylindrical fitting portion (60) and an inner peripheral surface of the cylindrical coupling tube (67) coupled to a Z4 gear (62) are fitted and coupled to each other. The annular groove (59) is closed by the fitting portion (60) in a state where the protruding portion (57) and the coupling tube (67) are coupled to each other. The annular groove (59) is configured so as to prevent foreign matter from being discharged toward a bearing gear (25).</p> |
