| 摘要 |
PURPOSE:To decrease control force to a very small level while form the whole unit of a transmission in a compact size, by forcedly sliding a movable pulley piece through a threaded mechanism utilizing a turning effect of a driving shaft. CONSTITUTION:A driving shaft 1 fits by a spline a fixed pulley piece 14, movable pulley piece 6 and a gear 27 to be rotated together. A clutch shaft 33, being rotated by engaging a clutch 48 with a forward rotary gear or an inverting gear 43, turns a gear 44 and a gear 29. If the gear 29 with an external thread rotates, an external threaded part 28, being screwed to an interval threaded part 30 in a boss 31 fixed to a frame 25, slides the gear 29 with the external thread to be moved in the axial direction in accordance with direction of rotation. In this way, the movable pulley piece 6, whose movement in the axial direction is restricted through a thrust bearing 51 and the gear 27, is slided in the axial direction. |
