| 摘要 |
PURPOSE:To provide a compact reduction gear with infinitely variable reduction ratio by mounting a pair of reduction gears respectively provided planet rotary mechanisms and having different reduction ratios on different diameter portions of a same stepped rotary input shaft to utilize the difference between the diameters of the shaft. CONSTITUTION:An input shaft 1 is a stepped one provided with different diameter portions 1A, 1B and journalled by a support 3 provided with a bearing 5. A plurality of bearings 9 are arranged in equal intervals on said larger diameter portion 1A and respectively fitted on a plurality of pins 7 planted on the support 3, while an annular body 11 coaxial with the shaft 1 is arranged around the outer periphery of the bearings 9. Also, a plurality of bearings 13 similar to the bearings 9 are arranged to make rolling contact with the smaller diameter portion 1B. Then, the dameter r5 of the bearing 13 is larger than the diameter r3 of the bearing 9 and the bearings 13 contact closely the annular body 11. Thus, the large and small diameter portions 1A, 1B can be respectively formed with first and second planet rotary type reduction gear mechanisms 10, 20. |
