US 12,172,731 B2
Electric power assist device for bicycles and bicycle
Kenji Tsukamoto, Saitama (JP)
Assigned to HONDA MOTOR CO., LTD., Tokyo (JP)
Appl. No. 17/605,427
Filed by HONDA MOTOR CO., LTD., Tokyo (JP)
PCT Filed Feb. 18, 2020, PCT No. PCT/JP2020/006241
§ 371(c)(1), (2) Date Oct. 21, 2021,
PCT Pub. No. WO2020/217664, PCT Pub. Date Oct. 29, 2020.
Claims priority of application No. 2019-084258 (JP), filed on Apr. 25, 2019.
Prior Publication US 2022/0212750 A1, Jul. 7, 2022
Int. Cl. B62M 6/50 (2010.01); B62J 45/20 (2020.01); B62J 45/415 (2020.01); B62M 6/55 (2010.01); B62M 6/90 (2010.01)
CPC B62M 6/50 (2013.01) [B62J 45/20 (2020.02); B62J 45/415 (2020.02); B62M 6/55 (2013.01); B62M 6/90 (2013.01)] 15 Claims
OG exemplary drawing
 
1. An electric power assist device for bicycles, the device comprising:
a housing which can be attached 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 or 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 further comprises a tilt angle detector for detecting a tilt angle with respect to a direction of gravity, and
wherein the control unit comprises 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, wherein the calibrator determines the absolute angle of the rotational angle sensor when the rotating member is rotated to or positioned at a predetermined rotational position with respect to the housing.