An electric power assist device includes a housing for attaching to a frame structure of a bicycle; an electric motor provided in the housing; a rotating member rotatably supported by the housing, rotationally driven by the electric motor, and connected to a crankshaft/crankarm of the bicycle in a torque transmitting relationship; a rotational angle sensor provided in the housing and configured to detect a rotational angle of the electric motor or the rotating member; and a control unit for controlling operation of the electric motor based on the rotational angle detected by the rotational angle sensor, wherein the electric power assist device has a tilt angle detector for detecting a tilt angle with respect to a direction of gravity, the control unit having a calibrator for determining an absolute angle of the rotational angle detected by the rotational angle sensor based on an output signal from the tilt angle detector.
Electric power assist device for bicycles and bicycle
2024-12-24
Patent
Electronic Resource
English