Drive unit and electrically assisted bicycle

Patent metadata

Field	Value
Publication number	US-12202571-B2
Application number	US-202017064675-A
Country	US
Kind code	B2
Filing date	Oct 7, 2020
Priority date	Oct 11, 2019
Publication date	Jan 21, 2025
Grant date	Jan 21, 2025

Abstract

A drive unit for an electrically assisted bicycle includes a one-way clutch including an inner member linked to an end of a connecting shaft and an outer member linked to a drive sprocket wheel. The inner member includes clutch pawls and a boss. The outer member includes clutch teeth that are able to engage with the clutch pawls and an extension to be coupled to the drive sprocket wheel. The extension includes a recess to accept the boss at an inner member side thereof. The recess has an inner peripheral surface that is able to slide against an outer peripheral surface of the boss.

First claim

What is claimed is:

1. A drive unit mountable to a body frame of an electrically assisted bicycle to generate a driving power which is transmitted to a wheel of the electrically assisted bicycle, the drive unit comprising:
a housing;
an electric motor fixed to the housing;
a pedal crank shaft extending through the housing along a right-left direction of the electrically assisted bicycle and being rotatably supported by the housing;
a connecting shaft through which the pedal crank shaft extends to transmit a pedaling force from a first end to a second end thereof, the first end being coupled to the pedal crank shaft; and
a one-way clutch to transmit the pedaling force from the second end of the connecting shaft to a drive sprocket wheel; wherein
the one-way clutch includes:
an inner member linked to the second end of the connecting shaft; and
an outer member linked to the drive sprocket wheel;

the inner member includes:
a plurality of clutch pawls to restrict rotation of the outer member relative to the inner member in one direction;
a base on which the plurality of clutch pawls are provided; and
a boss protruding from one end of the base toward a side where the drive sprocket wheel is located to cause a center axis of the outer member to be aligned with a center axis of the inner member;

the outer member includes:
a plurality of clutch teeth able to engage with the plurality of clutch pawls; and
an extension coupled to the drive sprocket wheel;

the extension includes a recess to accommodate the boss at an inner member side thereof, and the recess has an inner peripheral surface that is able to slide against an outer peripheral surface of the boss; and
the boss is located closer to the pedal crank shaft than to the plurality of clutch pawls.

2. A drive unit mountable to a body frame of an electrically assisted bicycle to generate a driving power which is transmitted to a wheel of the electrically assisted bicycle, the drive unit comprising:
a housing;
an electric motor fixed to the housing;
a pedal crank shaft extending through the housing along a right-left direction of the electrically assisted bicycle and being rotatably supported by the housing;
a connecting shaft through which the pedal crank shaft extends to transmit a pedaling force from a first end to a second end thereof, the first end being coupled to the pedal crank shaft; and
a one-way clutch to transmit the pedaling force from the second end of the connecting shaft to a drive sprocket wheel; wherein
the one-way clutch includes:
an inner member linked to the second end of the connecting shaft; and
an outer member linked to the drive sprocket wheel;

the inner member includes:
a plurality of clutch pawls to restrict rotation of the outer member relative to the inner member in one direction;
a base on which the plurality of clutch pawls are provided; and
a boss protruding from one end of the base toward a side where the drive sprocket wheel is located to cause a center axis of the outer member to be aligned with a center axis of the inner member;

the outer member includes:
a plurality of clutch teeth able to engage with the plurality of clutch pawls; and
an extension coupled to the drive sprocket wheel;

the extension includes a recess to accommodate the boss at an inner member side thereof, and the recess has an inner peripheral surface that is able to slide against an outer peripheral surface of the boss; and
the drive unit further includes a plain bearing positioned between the outer member and the pedal crank shaft, and no plain bearing is positioned between the inner member and the pedal crank shaft.

3. The drive unit of claim 2 , wherein a gap is provided between an inner peripheral surface of the inner member and an outer peripheral surface of the pedal crank shaft.

4. The drive unit of claim 2 , wherein only one plain bearing is positioned between the outer member and the pedal crank shaft.

Assignees

• Yamaha Motor Co Ltd

Inventors

• Shimizu Tatsunori
• Suzuki Ryota
• Usami Tomohiro

Classifications

• F16D41/12

  with hinged pawl co-operating with teeth, cogs, or the like (F16D41/02, F16D41/24 take precedence) · CPC title

• B62M3/00

  Construction of cranks operated by hand or foot · CPC title

• F16C9/02

  Crankshaft bearings · CPC title

• F16D41/30

  with hinged pawl co-operating with teeth, cogs, or the like · CPC title

• F16D2300/12

  Mounting or assembling · CPC title