Drive unit and electrically assisted bicycle

Patent metadata

Field	Value
Publication number	US-10933944-B2
Application number	US-201816055204-A
Country	US
Kind code	B2
Filing date	Aug 6, 2018
Priority date	Aug 9, 2017
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

A drive unit for an electrically assisted bicycle includes a housing, a motor in the housing, a crank shaft extending through the housing along a right-left direction of the bicycle, and a pair of bearings rotatably supporting the crank shaft within the housing, wherein each bearing includes an inner ring and an outer ring. The pair of bearings include a first bearing at one side of a thrust direction and a second bearing at another side along the thrust direction, wherein the thrust direction is an axial direction of the crank shaft. The first bearing does not move along the thrust direction relative to the crank shaft. The drive unit has a movement restricting structure that restricts movement of the first bearing relative to the relative to the housing along the thrust direction.

First claim

What is claimed is:

1. A drive unit for generating a driving power which is transmitted to a wheel of an electrically assisted bicycle, the drive unit comprising:
a housing;
a motor accommodated in the housing;
a crank shaft extending through the housing along a right-left direction of the bicycle; and
a pair of bearings rotatably supporting the crank shaft within the housing, each of the pair of bearings including an inner ring and an outer ring; wherein
the pair of bearings define a first bearing which is provided at one side along a thrust direction and a second bearing which is provided at another side along the thrust direction, the thrust direction corresponding to an axial direction of the crank shaft;
the first bearing is disposed so as not to move along the thrust direction relative to the crank shaft; and
the drive unit further comprises a movement restricting structure that restricts movement of the first bearing relative to the housing along the thrust direction;
the outer ring of the first bearing includes an inner peripheral surface, an outer peripheral surface, and a first end surface and a second end surface that connect the inner peripheral surface and the outer peripheral surface to each other;
the first end surface is located farther outward in the right-left direction of the bicycle than is the second end surface;
the housing includes a first abutment which abuts with the first end surface of the outer ring of the first bearing;
the movement restricting structure includes the first abutment of the housing;
the movement restricting structure further includes a plate fixed to the housing, the plate including a second abutment which abuts with the second end surface of the outer ring of the first bearing so that the outer ring of the first bearing is sandwiched by the second abutment and the first abutment of the housing;
the plate includes an alignment section that engages with a predetermined portion of the housing;
the alignment section includes a first extension that extends from the second abutment in a direction which is inclined with respect to the thrust direction, a second extension that extends from the first extension in a direction which intersects the first extension, and a recess defined by the second extension; and
the recess of the alignment section engages with the predetermined portion of the housing.

2. The drive unit of claim 1 , wherein the inner ring of the first bearing is press-fitted to the crank shaft.

3. The drive unit of claim 2 , wherein the plate is fixed to the housing by a fastener.

4. The drive unit of claim 2 , wherein
the housing includes an indent into which the outer ring of the first bearing is press-fitted; and
the movement restricting structure includes the indent of the housing and the outer ring of the first bearing press-fitted to the indent.

5. The drive unit of claim 1 , wherein
the inner ring of the first bearing includes an inner peripheral surface, an outer peripheral surface, and a first end surface and a second end surface that connect the inner peripheral surface and the outer peripheral surface to each other;
the drive unit further comprises a first circlip and a second circlip sandwiching the inner ring of the first bearing, the first circlip abutting with the first end surface, and the second circlip abutting with the second end surface;
the housing includes an indent into which the outer ring of the first bearing is press-fitted; and
the movement restricting structure includes the indent of the housing and the outer ring of the first bearing press-fitted into the indent.

6. The drive unit of claim 5 , wherein
the drive unit further comprises a third circlip which abuts with the second end surface of the outer ring of the first bearing.

7. An electrically assisted bicycle comprising the drive unit of claim 1 .

8. A drive unit for generating a driving power which is transmitted to a wheel of an electrically assisted bicycle, the drive unit comprising:
a housing;
a motor accommodated in the housing;
a crank shaft extending through the housing along a right-left direction of the bicycle; and
a pair of bearings rotatably supporting the crank shaft within the housing, each of the pair of bearings including an inner ring and an outer ring; wherein
the pair of bearings define a first bearing which is provided at one side along a thrust direction and a second bearing which is provided at another side along the thrust direction, the thrust direction corresponding to an axial direction of the crank shaft;
the first bearing is disposed so as not to move along the thrust direction relative to the crank shaft;
the drive unit further comprises a movement restricting structure that restricts movement of the first bearing relative to the housing along the thrust direction;
the inner ring of the first bearing is press-fitted to the crank shaft;
the outer ring of the first bearing includes an inner peripheral surface, an outer peripheral surface, and a first end surface and a second end surface that connect the inner peripheral surface and the outer peripheral surface to each other;
the first end surface is located farther outward in the right-left direction of the bicycle than is the second end surface;
the housing includes a first abutment which abuts with the first end surface of the outer ring of the first bearing;
the movement restricting structure includes the first abutment of the housing;
the movement restricting structure further includes a plate fixed to the housing, the plate including a second abutment which abuts with the second end surface of the outer ring of the first bearing so that the outer ring of the first bearing is sandwiched by the second abutment and the first abutment of the housing;
the housing includes a protrusion which is continuous with the first abutment and which protrudes along the thrust direction so as to surround the first bearing;
the plate includes a press-fit portion which extends along the thrust direction and which is press-fitted onto the protrusion of the housing; and
the plate is fixed to the housing by the press-fit portion.

Assignees

• Yamaha Motor Co Ltd

Inventors

• Usami Tomohiro

Classifications

• Y02T10/70

  Energy storage systems for electromobility, e.g. batteries · CPC title

• B62J45/421

  at the pedal crank · CPC title

• B62J45/411

  Torque sensors · CPC title

• B60L58/12

  responding to state of charge [SoC] · CPC title

• B60L2240/423

  Torque · CPC title