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EP-4741269-A1 - BYCICLE POWER TRANSMISSION DEVICE

EP4741269A1EP 4741269 A1EP4741269 A1EP 4741269A1EP-4741269-A1

Abstract

It is intended to enhance comfortableness in riding a bicycle in which a bicycle power transmission device is installed. The present bicycle power transmission device includes a first rotor, a second rotor, a friction member, and an elastic member. The second rotor is disposed to be rotatable relative to the first rotor. The friction member is disposed between the first rotor and the second rotor. The friction member is disposed to be rotatable relative to the first rotor. The friction member is configured to be rotated unitarily with the second rotor. The elastic member elastically couples the first rotor and the second rotor therethrough to each other. The friction member includes a base portion, a pawl portion, and a protruding portion. The base portion has an annular shape. The pawl portion extends from the base portion to a first side in an axial direction. The protruding portion is disposed radially inside the pawl portion. The protruding portion protrudes from the base portion to the first side in the axial direction. The second rotor includes an engaging hole and an engaging recess. The engaging hole causes the pawl portion to be engaged therewith. The engaging recess causes the protruding portion to be engaged therewith.

Inventors

  • HARIMA, KENJI
  • OHSHIMA, HIROSHI

Assignees

  • Exedy Corporation

Dates

Publication Date
20260513
Application Date
20251017

Claims (8)

  1. A bicycle power transmission device comprising: a first rotor; a second rotor disposed to be rotatable relative to the first rotor; a friction member disposed between the first rotor and the second rotor, the friction member disposed to be rotatable relative to the first rotor, the friction member configured to be rotated unitarily with the second rotor; and an elastic member elastically coupling the first rotor and the second rotor therethrough to each other, wherein the friction member includes a base portion having an annular shape, a pawl portion extending from the base portion to a first side in an axial direction, and a protruding portion disposed radially inside the pawl portion, the protruding portion protruding from the base portion to the first side in the axial direction, and the second rotor includes an engaging hole causing the pawl portion to be engaged therewith, and an engaging recess causing the protruding portion to be engaged therewith.
  2. The bicycle power transmission device according to claim 1, wherein the friction member includes a plurality of the pawl portions, and a plurality of the protruding portions, and the plurality of pawl portions and the plurality of protruding portions are alternately disposed in a circumferential direction.
  3. The bicycle power transmission device according to claim 1, wherein the protruding portion overlaps with the elastic member as seen in a radial direction.
  4. The bicycle power transmission device according to claim 1, wherein the friction member includes a plurality of the pawl portions, the plurality of pawl portions disposed away from each other at intervals in a circumferential direction, and an outer wall portion protruding from the base portion to the first side in the axial direction, the outer wall portion disposed circumferentially between a pair of pawl portions adjacent to each other in the plurality of pawl portions, the outer wall portion extending in the circumferential direction, and the outer wall portion includes an inner surface oriented radially inward, and a recess provided on the inner surface, the recess recessing radially outward.
  5. The bicycle power transmission device according to claim 1, wherein the friction member includes a plurality of the pawl portions, the plurality of pawl portions disposed away from each other at intervals in a circumferential direction, and an outer wall portion protruding from the base portion to the first side in the axial direction, the outer wall portion disposed circumferentially between a pair of pawl portions adjacent to each other in the plurality of pawl portions, the outer wall portion extending in the circumferential direction, and the outer wall portion is disposed away from the pair of pawl portions at intervals in the circumferential direction.
  6. The bicycle power transmission device according to claim 1, wherein the first rotor includes a hub portion extending in the axial direction, and a flange portion extending radially outward from the hub portion, the second rotor includes a first plate disposed on the first side of the flange portion in the axial direction, and a second plate disposed on a second side of the flange portion in the axial direction, the second plate configured to be rotated unitarily with the first plate, the friction member is disposed axially between the flange portion and the first plate, and the first plate includes the engaging hole and the engaging recess.
  7. The bicycle power transmission device according to claim 6, further comprising: a sprocket attached to the first plate.
  8. The bicycle power transmission device according to claim 1, wherein the friction member includes a cylindrical portion protruding from an inner peripheral end of the base portion to the first side in the axial direction, and the protruding portion is disposed radially outside the cylindrical portion, the protruding portion integrated with the cylindrical portion.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is based on and claims the priority benefit of Japanese application No. 2024-194362 filed on November 6, 2024, the contents of which are incorporated herein by reference. TECHNICAL FIELD The present invention relates to a bicycle power transmission device. BACKGROUND A bicycle power transmission includes a first rotor and a second rotor (e.g., Japan Laid-open Patent Application Publication No. 2024-084007). The first and second rotors are configured to be rotatable relative to each other. The first and second rotors are elastically coupled to each other through coil springs. When a torque is inputted to the first rotor, the first rotor is rotated relative to the second rotor, whereby the coil springs are compressed. When the torque inputted to the first rotor is reduced in magnitude, the input torque can be compensated by the resilience of the coil springs. SUMMARY OF THE INVENTION It is an object of the present invention to enhance comfortableness in riding a bicycle in which a bicycle power transmission is installed. A bicycle power transmission device according to a first aspect includes a first rotor, a second rotor, a friction member, and an elastic member. The second rotor is disposed to be rotatable relative to the first rotor. The friction member is disposed between the first rotor and the second rotor. The friction member is disposed to be rotatable relative to the first rotor. The friction member is configured to be rotated unitarily with the second rotor. The elastic member elastically couples the first rotor and the second rotor therethrough to each other. The friction member includes a base portion, a pawl portion, and a protruding portion. The base portion has an annular shape. The pawl portion extends from the base portion to a first side in an axial direction. The protruding portion is disposed radially inside the pawl portion. The protruding portion protrudes from the base portion to the first side in the axial direction. The second rotor includes an engaging hole and an engaging recess. The engaging hole causes the pawl portion to be engaged therewith. The engaging recess causes the protruding portion to be engaged therewith. According to the configuration, when the first and second rotors are rotated relative to each other by the resilience of the elastic member, the friction member is slid against the first rotor; hence, the relative rotation between the first and second rotor can be made smooth. As a result, it is made possible to enhance comfortableness in riding a bicycle in which the present bicycle power transmission device is installed. Besides, the friction member is engaged at the pawl portion thereof with the engaging hole of the second rotor, while being engaged at the protruding portion thereof, disposed radially inside the pawl portion, with the engaging recess of the second rotor. Because of this, attaching the friction member to the second rotor can be made secure, whereby generating a friction torque between the first rotor and the friction member can be made stable. As a result, the relative rotation between the first and second rotors can be made smoother, whereby it is made possible to further enhance comfortableness in riding the bicycle. A bicycle power transmission device according to a second aspect relates to the bicycle power transmission device according to the first aspect and is configured as follows. The friction member includes a plurality of the pawl portions and a plurality of the protruding portions. The plurality of pawl portions and the plurality of protruding portions are alternately disposed in a circumferential direction. A bicycle power transmission device according to a third aspect relates to the bicycle power transmission device according to the first or second aspect and is configured as follows. The protruding portion overlaps with the elastic member as seen in a radial direction. A bicycle power transmission device according to a fourth aspect relates to the bicycle power transmission device according to any of the first to third aspects and is configured as follows. The friction member includes a plurality of the pawl portions and an outer wall portion. The plurality of pawl portions are disposed away from each other at intervals in a circumferential direction. The outer wall portion protrudes from the base portion to the first side in the axial direction. The outer wall portion is disposed circumferentially between a pair of pawl portions adjacent to each other in the plurality of pawl portions and extends in the circumferential direction. The outer wall portion includes an inner surface and a recess. The inner surface is oriented radially inward. The recess is provided on the inner surface. The recess recesses radially outward. A bicycle power transmission device according to a fifth aspect relates to the bicycle power transmission device according to any of the first to fourth aspects