Drive unit and electric-motor-assisted bicycle

Patent metadata

Field	Value
Publication number	US-9834278-B2
Application number	US-201715453973-A
Country	US
Kind code	B2
Filing date	Mar 9, 2017
Priority date	Apr 28, 2016
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

In a drive unit in an electric-motor-assisted bicycle, as viewed in an axial direction of the crank axle, a substrate housed in a housing does not overlap a reduction gear but overlaps a driven gear. The substrate is disposed around the crank axle and includes a component side extending in a direction crossing the central axis of the crank axle. The substrate extends in directions crossing radial directions of the crank axle. One end of the substrate in the direction in which the substrate extends is located on the side of the straight line connecting the shaft center of the crank axle and the shaft center of the motor output shaft as viewed in the axial direction, that is opposite to the side having the other end of the substrate in the direction in which the substrate extends.

First claim

What is claimed is:

1. A drive unit attached to a vehicle-body frame of an electric-motor-assisted bicycle to generate a driving force to be transmitted to a rear wheel, the drive unit comprising:
a housing;
a crank axle extending through the housing in a left-to-right direction of the bicycle;
a crank rotation input shaft, the crank axle extending through the crank rotation input shaft, an end of the crank rotation input shaft being coupled to the crank axle;
a motor housed in the housing, the motor including a motor output shaft, an output gear being provided on the motor output shaft;
a reduction gear housed in the housing, the reduction gear that engages with the output gear;
a resultant-force output axle, the crank axle extending through the resultant-force output axle, the resultant-force output axle being connected to an other end of the crank rotation input shaft with a one-way clutch provided in between, the resultant-force output axle including a driven gear that engages the reduction gear; and
a substrate housed in the housing; wherein
as viewed in an axial direction of the crank axle, the substrate does not overlap the reduction gear but does overlap the driven gear, the substrate is disposed around the crank axle, the substrate includes a component side extending in a direction crossing a central axis of the crank axle, and the substrate extends in directions crossing radial directions of the crank axle;
the substrate includes:
a first end; and
a second end located opposite to the first end in a direction in which the substrate extends;

a first straight line connecting a shaft center of the crank axle and a shaft center of the motor output shaft as viewed in the axial direction;
a second straight line passing through the shaft center of the crank axle and being perpendicular to the first straight line as viewed in the axial direction;
a third straight line passing through the shaft center of the motor output shaft and being perpendicular to the first straight line as viewed in the axial direction; wherein
a first region is located on one side of the first straight line as viewed in the axial direction; and
a second region is located on an other side of the first straight line that is opposite to the one side of the first straight line, as viewed in the axial direction;
the first end is located in the first region as viewed in the axial direction;
the second end is located in the second region as viewed in the axial direction; and
the first end and the second end are located between the second straight line and the third straight line as viewed in the axial direction.

2. The drive unit according to claim 1 , further comprising:
a rotation detector that detects rotation of the crank rotation input shaft; wherein
the crank rotation input shaft includes an attachment surface extending in a radial direction of the crank axle and overlapping the substrate as viewed in the axial direction; and
the rotation detector includes:
a ring magnet located on the attachment surface; and
a detector mounted on the substrate and positioned to face the ring magnet such that the detector and the ring magnet are arranged in the axial direction.

3. The drive unit according to claim 2 , wherein
the crank rotation input shaft includes a driver connected to the resultant-force output axle with the one-way clutch provided in between; and
the attachment surface is provided on the driver.

4. The drive unit according to claim 1 , wherein the substrate includes:
a controller configured or programmed to control the motor;
power circuitry mounted closer to the second end than the controller as measured in the direction in which the substrate extends, the power circuitry being supplied with electric power from a battery; and
an electricity supply mounted closer to the second end than the power circuitry as measured in the direction in which the substrate extends, the electricity supply supplying the motor with electric power.

5. The drive unit according to claim 4 , wherein, as viewed in the axial direction, the controller is located on the one side of the first straight line and the electricity supply is located on the other side of the first straight line, or the controller is located on the other side of the first straight line and the electricity supply is located on the one side of the first straight line.

6. The drive unit according to claim 5 , wherein
the housing includes an outlet located above the straight line as viewed in the axial direction such that a cable connected to the substrate is routed outwardly; and
as viewed in the axial direction, the electricity supply is located below the first straight line.

7. The drive unit according to claim 1 , wherein the substrate includes a sheet attached to at least a portion of the electricity supply, the sheet being in contact with the housing to transmit heat, generated as the electricity supply operates, to the housing.

8. The drive unit according to claim 7 , wherein the housing includes a heat sink that overlaps the sheet as viewed in the axial direction.

9. An electric-motor-assisted bicycle comprising:
the drive unit according to claim 1 .

Assignees

• Yamaha Motor Co Ltd

Inventors

• Uda Masatsugu
• Suzuki Ryota
• Mano Yasunori
• Usami Tomohiro

Classifications

• F16D41/24

  specially adapted for cycles · CPC title

• B62M6/50

  characterised by detectors or sensors, or arrangement thereof · CPC title

• B62M6/55 Primary

  power-driven at crank shafts parts · CPC title

• B62M11/02

  of unchangeable ratio · CPC title

• B62M6/40 Primary

  Rider propelled cycles with auxiliary electric motor · CPC title