Driving-side pulley

摘要

A driving-side pulley (100, 100', 100B) includes a cam mechanism (270, 270B) that presses a movable sleeve (200) in a first direction by utilizing a relative rotation of the movable sleeve (200) in the normal direction with respect to an axis-line-direction fixed member (55 or 110), the first direction being a direction that has a pressing surface (220a) pressed against a corresponding side surface of a belt (40).