| 摘要 |
A precision gearing device, e.g. a step-down gearing device, has a support body (10) in which are rotatably mounted in bearings (22, 24) input shafts (18, 20) with their rotational axes parallel. Each shaft (18, 20) is provided with a spur gear (28) which is rotatable by means of an input spur gear (30). Each shaft (18, 20) is provided with three cylindrical, eccentric portions (31, 33, 35). The first eccentric portions (31) of the two shafts are arranged to be in phase, and are rotatably mounted by means of bearings (40) and bushings (44) in diametrically opposed lobes of a first orbital ring gear (36). Similarly, the second eccentric portions (33) of the two shafts are in phase, and the third eccentric portions (35) are in phase, and are similarly mounted in diametrically opposed lobes of respective second and third orbital ring gears (37, 38). Each of the eccentrics (31, 33, 35) is 120 DEG out of phase with the other two. When the shafts (18, 20) are rotated, the movement of the eccentric portions causes each of the ring gears (36, 37, 38) to perform an orbital motion about a fixed axis. The orbital motion of the ring gears is used to drive an output gear (54). |
