| 摘要 |
PURPOSE:To obtain a large reduction ratio by a comparatively simple constitution wherein two small gears are rotatably supported onto an eccentric shaft and the small gears are respectively engaged with internal gears, which are fixed to an inner and an outer casings respectively. CONSTITUTION:When a first shaft part 118 is rotated under the condition that a flange 115 is fixed, small gears 109 and 110, which are rotatably supported onto a second shaft part 118a integrally and eccentrically provided on the shaft part 118, are rollingly moved on internal gears 107 and 108. In this case, let Z1 and Z2 denote the numbers of teeth of the internal gears 107 and 108 and Z3 and Z4 the numbers of teeth of the small gears 109 and 110, then a reduction ratio R is 1/R=1-Z1Z4/Z3Z2. This means that the reduced rotation with a large reduction ratio is obtained on an outer casing 101. The outer casing 101 is supported through bearings 103 onto the outer periphery of an inner casing 106. Furthermore, the internal gear 108 is fixed to said outer casing 101 by means of bolts 117. |
