Electric power-assisted bicycle and drive system therefor

• US 10,246,161 B2
• Filed: 06/27/2017
• Issued: 04/02/2019
• Est. Priority Date: 06/28/2016
• Status: Active Grant

• Current Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Original Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Inventors: Kinpara, Yuki
• Primary Examiner(s): Hurley, Kevin
• Application Number:
  US15/633,756
• Publication Number:
  US 20180009503A1
• Time in Patent Office: 644 Days
• CPC Class Codes: B62J 45/4151 for sensing lateral inclination of the cycle
• CPC Class Codes: B62M 6/45 Control or actuating devices therefor
• CPC Class Codes: B62M 6/50 characterised by detectors or sensors, or arrangement thereof
• CPC Class Codes: B62M 6/55 power-driven at crank shafts parts
• CPC Class Codes: B62M 6/90 Batteries
• CPC Class Codes: B62M 9/06 using a single chain, belt, or the like

Abstract

An electric power-assisted bicycle, comprising: a torque sensor for detecting pedaling force applied to the pedal; an inclination angle sensor for detecting rocking of the bicycle body in a lateral direction; an electric motor that assists drive of a drive wheel driven by pedaling of the rider; and a controller that controls the electric motor based on the pedaling force. The controller has a first mode and a second mode as control modes of the electric motor. The second mode is executed when the controller determines that the rider pedals the bicycle while rocking the bicycle body in the lateral direction. The controller executes different control in the second mode from that in the first mode to assist the drive of the drive wheel.

Claims

1. A drive system for an electric power-assisted bicycle, comprising:

a first sensor for detecting pedaling force applied to a pedal from a rider;

a second sensor for detecting rocking of a bicycle body in a lateral direction;

an electric motor that assists drive of a drive wheel driven by pedaling of the rider; and

a controller that controls the electric motor based on a pedaling force, wherein

the controller has a first mode and a second mode as control modes of the electric motor, the first mode is executed in a normal-pedaling mode, the second mode is executed when the controller determines based on at least output of the second sensor that the rider pedals the bicycle while rocking the bicycle body in the lateral direction, and the controller executes different control in the second mode from that in the first mode to assist the drive of the drive wheel.

2. The drive system for the electric power-assisted bicycle according to claim 1, wherein

under a condition that another pedaling force detected by the first sensor in the second mode is the same as that in the first mode, power obtained from the electric motor in the second mode is different from that in the first mode.

3. The drive system for the electric power-assisted bicycle according to claim 1, wherein

when an inclination of the bicycle body in one direction of either a left direction or a right direction is defined as a first inclination and an inclination of the bicycle body in the other direction of either the left direction or the right direction is defined as a second inclination, the controller determines that the rider pedals the bicycle while rocking the bicycle body in the lateral direction when the first inclination and the second inclination are detected a plurality of times.

4. The drive system for the electric power-assisted bicycle according to claim 1, wherein

the controller detects an inclination angle in the lateral direction of the bicycle body based on the output of the second sensor, and

the controller determines that the rider pedals the bicycle while rocking the bicycle body in the lateral direction based on the inclination angle in the lateral direction of the bicycle body.

5. The drive system for the electric power-assisted bicycle according to claim 1, wherein

the controller detects an acceleration in the lateral direction of the bicycle body based on the output of the second sensor, and

the controller determines that the rider pedals the bicycle while rocking the bicycle body in the lateral direction based on the acceleration in the lateral direction of the bicycle body.

6. The drive system for the electric power-assisted bicycle according to claim 1, further comprising a sensor that has output depending on a rotation position of the pedal, wherein

the controller determines that the rider pedals the bicycle while rocking the bicycle body in the lateral direction, based on the output of the second sensor and the output of the sensor depending on the rotation position of the pedal.

7. The drive system for the electric power-assisted bicycle according to claim 6, wherein

the first sensor is used as the sensor that has output depending on the rotation position of the pedal.

8. The drive system for the electric power-assisted bicycle according to claim 6, further comprising a third sensor for detecting rotation of a crank shaft provided with the pedal, wherein

the third sensor is used as the sensor that has output-depending on the rotation position of the pedal.

9. The drive system for the electric power-assisted bicycle according to claim 1, wherein

the controller controls the electric motor in the first mode so that the electric motor outputs an assisting torque corresponding to a first assisting ratio and the pedaling force detected by the first sensor, and

the controller controls the electric motor in the second mode so that the electric motor outputs an assisting torque corresponding to a second assisting ratio that is different from the first assisting ratio and the pedaling force detected by the first sensor.

10. The drive system for the electric power-assisted bicycle according to claim 1, wherein

the controller controls the electric motor in the first mode so that the assisting torque output from the electric motor changes due to rotation of a crank shaft provided with the pedal, and

the controller controls the electric motor in the second mode so that a local minimum of the assisting torque in the second mode is higher than a local minimum of the assisting torque in the first mode.

11. The drive system for the electric power-assisted bicycle according to claim 1, wherein

the controller controls the electric motor in the second mode so that amplitude of the assisting torque in the second mode is smaller than amplitude of the assisting torque in the first mode.

12. The drive system for the electric power-assisted bicycle according to claim 1, wherein

the controller controls the electric motor in the second mode so that amplitude of the assisting torque in the second mode is larger than amplitude of the assisting torque in the first mode.

13. The drive system for the electric power-assisted bicycle according to claim 12, wherein

the controller controls the electric motor in the first mode so that the assisting torque is constant without regard to change of the pedaling force applied to the pedal, and

the controller controls the electric motor in the second mode so that the assisting torque changes.

14. The drive system for the electric power-assisted bicycle according to claim 1, further comprising a notification device that notifies the rider that the controller controls the electric motor in the second mode.

15. An electric power-assisted bicycle including a drive system, the drive system comprising:

a first sensor for detecting pedaling force applied to a pedal from a rider;

a second sensor for detecting rocking of the bicycle body in a lateral direction;

an electric motor that assists drive of a drive wheel driven by pedaling of the rider; and

a controller that controls the electric motor based on a pedaling force, wherein

the controller has a first mode and a second mode as control modes of the electric motor, the first mode is executed in a normal-pedaling mode, the second mode is executed when the controller determines based on at least output of the second sensor that the rider pedals the bicycle while rocking the bicycle body in the lateral direction, and the controller executes different control in the second mode from that in the first mode to assist the drive of the drive wheel.