US Patent 9303763 Bicycle rear derailleur

A bicycle rear derailleur includes a base member, a movable member, a linkage and a motor unit. The base member is configured to be mounted to a bicycle. The movable member is movably coupled to the base member. The linkage includes an outer link pivotally connected to the base member about a first pivot axis and pivotally connected to the movable member about a second pivot axis, and an inner link pivotally connected the base member and the movable member. The motor unit includes an output shaft having a rotational axis being parallel to one of the first pivot axis and the second pivot axis. The output shaft of the motor unit drives the outer link to move the movable member with respect to the base member. The inner link moves in response to movement of the outer link.