| 摘要 |
PROBLEM TO BE SOLVED: To avoid a tooth jump by preventing the loosening of a chain without causing an increase of a power transmission loss, in a gear change mechanism using a composite sprocket.SOLUTION: A gear change mechanism comprises: two sets of composite sprockets 5 having moving mechanisms for radially moving a pinion sprocket and a guide rod; a chain 6 wound to both the composite sprockets; a fixed disc 10 in which a fixed radial groove inserted with the pinion sprocket and the guide rod is formed, and which integrally rotates together with a rotating shaft; a movable disc 19 in which a movable radial groove in which a support shaft is located in a cross point intersecting with the fixed radial groove is formed, and which can rotate with respect to the fixed disc; and a relative rotation drive mechanism 30 which rotationally drives the movable disc with respect to the fixed disc, and moves the cross point to a radial direction. The gear change mechanism also comprises an initial phase adjustment mechanism 80 which changes an initial phase of the movable disc with respect to the fixed disc, and displaces the cross point to the radial direction.SELECTED DRAWING: Figure 1 |
