US 11,794,854 B2
Bicycle electric power assist device and bicycle
Kenji Tsukamoto, Saitama (JP); and Satoshi Honda, Saitama (JP)
Assigned to HONDA MOTOR CO., LTD., Tokyo (JP)
Appl. No. 17/420,697
Filed by HONDA MOTOR CO., LTD., Tokyo (JP)
PCT Filed Dec. 26, 2019, PCT No. PCT/JP2019/051111
§ 371(c)(1), (2) Date Jul. 5, 2021,
PCT Pub. No. WO2020/158280, PCT Pub. Date Aug. 6, 2020.
Claims priority of application No. 2019-016938 (JP), filed on Feb. 1, 2019; and application No. 2019-052798 (JP), filed on Mar. 20, 2019.
Prior Publication US 2022/0097798 A1, Mar. 31, 2022
Int. Cl. B62M 6/50 (2010.01); H02K 11/21 (2016.01); H02K 7/14 (2006.01)
CPC B62M 6/50 (2013.01) [H02K 7/14 (2013.01); H02K 11/21 (2016.01)] 20 Claims
OG exemplary drawing
 
1. A bicycle electric power assist device, comprising:
an electric motor connected in a torque transmitting relationship to crank arms or a crankshaft driven by a pedal force from pedals via the crank arms;
a battery to be mounted on a bicycle to serve as a power supply for the electric motor;
a control unit configured to control operation of the electric motor;
a rotation angle sensor configured to detect a crank rotation angle position of the crankshaft; and
a current sensor configured to detect a motor current of the electric motor,
wherein the control unit comprises:
a pedal force estimation/calculation unit configured to estimate the pedal force from a difference between the motor current in a first crank rotation angle position and the motor current in a second crank rotation angle position which is different from the first crank rotation angle position; and
a motor drive control unit configured to control driving of the electric motor according to the pedal force estimated by the pedal force estimation/calculation unit.