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EP-4741270-A1 - BICYCLE POWER TRANSMISSION DEVICE

EP4741270A1EP 4741270 A1EP4741270 A1EP 4741270A1EP-4741270-A1

Abstract

It is intended to control in which direction a coil spring protrudes. The present bicycle power transmission device includes a first rotor, a first plate, a second plate, and a coil spring. The first rotor includes a hub portion, a flanged portion, and an accommodation hole. The hub portion extends in an axial direction. The flanged portion extends radially outward from the hub portion. The accommodation hole is provided in the flanged portion. The first plate is disposed on a first side of the flanged portion in the axial direction. The first plate is disposed to be rotatable relative to the flanged portion. The second plate is disposed on a second side of the flanged portion in the axial direction. The second plate is configured to be rotated unitarily with the first plate. The coil spring is disposed in the accommodation hole. The coil spring elastically couples the first rotor and both the first and second plates therethrough to each other. The flanged portion slants in the axial direction.

Inventors

  • HARIMA, KENJI
  • OHSHIMA, HIROSHI

Assignees

  • Exedy Corporation

Dates

Publication Date
20260513
Application Date
20251017

Claims (7)

  1. A bicycle power transmission device comprising: a first rotor including a hub portion extending in an axial direction, a flanged portion extending radially outward from the hub portion, and an accommodation hole provided in the flanged portion; a first plate disposed on a first side of the flanged portion in the axial direction, the first plate disposed to be rotatable relative to the flanged portion; a second plate disposed on a second side of the flanged portion in the axial direction, the second plate configured to be rotated unitarily with the first plate; and a coil spring disposed in the accommodation hole, the coil spring elastically coupling the first rotor and both the first and second plates therethrough to each other, wherein the flanged portion slants in the axial direction.
  2. The bicycle power transmission device according to claim 1, further comprising: a sprocket attached to the first plate, wherein the flanged portion slants to the second side in the axial direction.
  3. The bicycle power transmission device according to claim 1, further comprising: a crank arm attached to an axially second-side end of the hub portion, wherein the flanged portion slants to the second side in the axial direction.
  4. The bicycle power transmission device according to claim 1, wherein the flanged portion includes a flange body extending radially outward from the hub portion, and a slant portion extending radially outward from an outer peripheral end of the flange body, the slant portion slanting in the axial direction.
  5. The bicycle power transmission device according to claim 4, wherein the accommodation hole is provided across the flange body and the slant portion.
  6. The bicycle power transmission device according to claim 4, wherein the coil spring is contacted at an end surface thereof with the flange body and the slant portion.
  7. The bicycle power transmission device according to claim 1, wherein the hub portion has a cylindrical shape, and the first rotor includes a plurality of protruding portions provided on an inner peripheral surface of the hub portion to extend therefrom in the axial direction, and a plurality of relief portions, each of the plurality of relief portions provided on at least one of both axial ends of each of the plurality of protruding portions.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is based on and claims the priority benefit of Japanese application No. 2024-194361 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 device includes a first rotor, a first plate, and a second plate (see e.g., Japan Laid-open Patent Application Publication No. 2024-084007). The first and second plates are configured to be rotated unitarily with each other. The first rotor and both the first and second plates are elastically coupled to each other through coil springs. When described in detail, the coil springs are disposed in accommodation holes of the first rotor, window portions of the first plate, and window portions of the second plate, respectively. SUMMARY OF THE INVENTION It is an object of the present invention to provide a bicycle power transmission device enabled to control in which direction a coil spring protrudes. A bicycle power transmission device according to a first aspect includes a first rotor, a first plate, a second plate, and a coil spring. The first rotor includes a hub portion, a flanged portion, and an accommodation hole. The hub portion extends in an axial direction. The flanged portion extends radially outward from the hub portion. The accommodation hole is provided in the flanged portion. The first plate is disposed on a first side of the flanged portion in the axial direction. The first plate is disposed to be rotatable relative to the flanged portion. The second plate is disposed on a second side of the flanged portion in the axial direction. The second plate is configured to be rotated unitarily with the first plate. The coil spring is disposed in the accommodation hole. The coil spring elastically couples the first rotor and both the first and second plates therethrough to each other. The flanged portion slants in the axial direction. According to the configuration, the flanged portion slants in the axial direction; hence, the flanged portion is made contactable with the coil spring at a position displaced from the center of the coil spring. Because of this, when the coil spring is pressed by the flanged portion and is thereby compressed, the coil spring is simultaneously applied with a rotation-directional load and an axial load oriented in opposition to the slant direction of the flanged portion. Thus, it is made possible to control in which direction the coil spring protrudes by slanting the flanged portion to a side that is not preferable for protrusion of the coil spring in the axial direction. A bicycle power transmission device according to a second aspect relates to the bicycle power transmission device according to the first aspect and further includes a sprocket attached to the first plate. The flanged portion slants to the second side in the axial 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 further includes a crank arm attached to an axially second-side end of the hub portion. The flanged portion slants to the second side in the axial direction. According to the configuration, it is made possible to prevent the coil spring from protruding toward the crank arm, i.e., toward a rider of a bicycle. 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 flanged portion includes a flange body and a slant portion. The flange body extends radially outward from the hub portion. The slant portion extends radially outward from an outer peripheral end of the flange body. The slant portion slants in the axial direction. A bicycle power transmission device according to a fifth aspect relates to the bicycle power transmission device according to the fourth aspect and is configured as follows. The accommodation hole is provided across the flange body and the slant portion. A bicycle power transmission device according to a sixth aspect relates to the bicycle power transmission device according to the fourth or fifth aspect and is configured as follows. The coil spring is contacted at an end surface thereof with the flange body and the slant portion. A bicycle power transmission device according to a seventh aspect relates to the bicycle power transmission device according to any of the first to sixth aspects and is configured as follows. The hub portion has a cylindrical shape. The first rotor includes a plurality of protruding portions and a plurality of relief portions. The plurality of protruding portions are provided on an inner peripheral surface of the hub portion to extend therefrom in the axial direction. Each of the plurality of relief portions is provided on at least one of both axial ends of each