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EP-4741267-A1 - BICYCLE POWER TRANSMISSION DEVICE

EP4741267A1EP 4741267 A1EP4741267 A1EP 4741267A1EP-4741267-A1

Abstract

It is intended to achieve enhancement in strength of a screw portion. The present bicycle power transmission device includes a first rotor, a second rotor, an elastic member, a stopper member, and a first nut. The first rotor includes a stopper surface oriented in a circumferential direction. The second rotor is disposed to be rotatable relative to the first rotor. The elastic member elastically couples the first rotor and the second rotor therethrough to each other. The stopper member is attached to the second rotor. The stopper member includes a stopper portion and a first screw portion. The stopper portion is opposed to the stopper surface in the circumferential direction. The first screw portion is integrated with the stopper portion and extends in an axial direction. The first nut is screwed onto the first screw portion.

Inventors

  • HARIMA, KENJI

Assignees

  • Exedy Corporation

Dates

Publication Date
20260513
Application Date
20251017

Claims (9)

  1. A bicycle power transmission device comprising: a first rotor including a stopper surface, the stopper surface oriented in a circumferential direction; a second rotor disposed to be rotatable relative to the first rotor; an elastic member elastically coupling the first rotor and the second rotor therethrough to each other; a stopper member attached to the second rotor, the stopper member including a stopper portion and a first screw portion, the stopper portion opposed to the stopper surface in the circumferential direction, the first screw portion integrated with the stopper portion, the first screw portion extending in an axial direction; and a first nut screwed onto the first screw portion.
  2. The bicycle power transmission device according to claim 1, wherein the second rotor includes a first through hole, the stopper member includes a first intermediate portion, the first intermediate portion disposed between the stopper portion and the first screw portion in the axial direction, the first intermediate portion is smaller in outer diameter than the stopper portion, the first intermediate portion being larger in outer diameter than the first screw portion, and the first intermediate portion is disposed inside the first through hole.
  3. The bicycle power transmission device according to claim 2, further comprising: a sprocket rotated unitarily with the second rotor, the sprocket including an engaging hole, the engaging hole overlapping with the first through hole as seen in the axial direction, wherein the first intermediate portion is disposed inside the engaging hole.
  4. The bicycle power transmission device according to claim 2, wherein the stopper member includes a constricted portion, the constricted portion disposed between the first intermediate portion and the first screw portion.
  5. The bicycle power transmission device according to claim 2, wherein the stopper member includes a constricted portion, the constricted portion disposed between the stopper portion and the first intermediate portion.
  6. The bicycle power transmission device according to claim 1, wherein the first nut is a flanged nut.
  7. The bicycle power transmission device according to claim 1, wherein the stopper member includes an engaging portion, the engaging portion configured to enable a tool to be engaged therewith.
  8. The bicycle power transmission device according to claim 1, further comprising: a second nut, wherein the second rotor includes a first plate and a second plate, the first plate disposed on a first side of the first rotor in the axial direction, the second plate disposed on a second side of the first rotor in the axial direction, the stopper portion is disposed between the first plate and the second plate in the axial direction, the first screw portion is disposed on the first side of the first plate in the axial direction, the stopper member includes a second screw portion, the second screw portion disposed on the second side of the second plate in the axial direction, the second screw portion integrated with the stopper portion, and the second nut is screwed onto the second screw portion.
  9. The bicycle power transmission device according to claim 8, wherein the first plate includes a first through hole, the second plate includes a second through hole, the second through hole overlapping with the first through hole as seen in the axial direction, the stopper member includes a first intermediate portion and a second intermediate portion, the first intermediate portion disposed between the stopper portion and the first screw portion in the axial direction, the second intermediate portion disposed between the stopper portion and the second screw portion in the axial direction, each of the first and second intermediate portions is smaller in outer diameter than the stopper portion, the each of the first and second intermediate portions being larger in outer diameter than the first screw portion, the first intermediate portion is disposed inside the first through hole, and the second intermediate portion is disposed inside the second through hole.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is based on and claims the priority benefit of Japanese application No. 2024-194359 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 and a second rotor that are disposed to be rotatable relative to each other. The first and second rotors are elastically coupled to each other through elastic members. The angular range of torsion (relative rotation) between the first and second rotors is restricted by stopper members. Japan Laid-open Patent Application Publication No. 2024-084007 discloses a bicycle power transmission device that the maximum angle of torsion between the first and second rotors is made changeable by replacing the stopper members. The stopper members are attached to the bicycle power transmission device by bolts for fastening the second rotor in place. Each bolt extends to penetrate the interior of each stopper member. SUMMARY OF THE INVENTION Enhancement in strength of a screw portion of each bolt has been demanded for such a reason as rigidly fastening the second rotor in place. In view of this, it is an object of the present invention to achieve enhancement in strength of the screw portion. A bicycle power transmission device according to a first aspect includes a first rotor, a second rotor, an elastic member, a stopper member, and a first nut. The first rotor includes a stopper surface oriented in a circumferential direction. The second rotor is disposed to be rotatable relative to the first rotor. The elastic member elastically couples the first rotor and the second rotor therethrough to each other. The stopper member is attached to the second rotor. The stopper member includes a stopper portion and a first screw portion. The stopper portion is opposed to the stopper surface in the circumferential direction. The first screw portion is integrated with the stopper portion and extends in an axial direction. The first nut is screwed onto the first screw portion. According to the configuration, the screw portion is integrated with the stopper portion; hence, the screw portion can be made larger in diameter than that of a bolt extending inside a cylindrical stopper portion as seen in a related art. As a result, it is made possible to achieve enhancement in strength of the screw portion. 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 second rotor includes a first through hole. The stopper member includes a first intermediate portion. The first intermediate portion is disposed between the stopper portion and the first screw portion in the axial direction. The first intermediate portion is smaller in outer diameter than the stopper portion and is larger in outer diameter than the first screw portion. The first intermediate portion is disposed inside the first through hole. A bicycle power transmission device according to a third aspect relates to the bicycle power transmission device according to the second aspect and further includes a sprocket. The sprocket is rotated unitarily with the second rotor. The sprocket includes an engaging hole. The engaging hole overlaps with the first through hole as seen in the axial direction. The first intermediate portion is disposed inside the engaging hole. A bicycle power transmission device according to a fourth aspect relates to the bicycle power transmission device according to the second or third aspect and is configured as follows. The stopper member includes a constricted portion. The constricted portion is disposed between the first intermediate portion and the first screw portion. According to the configuration, it is made possible to ease a stress acting inside the stopper member. A bicycle power transmission device according to a fifth aspect relates to the bicycle power transmission device according to any of the second to fourth aspects and is configured as follows. The stopper member includes a constricted portion. The constricted portion is disposed between the stopper portion and the first intermediate portion. According to the configuration, it is made possible to ease a stress acting inside the stopper member. A bicycle power transmission device according to a sixth aspect relates to the bicycle power transmission device according to any of the first to fifth aspects and is configured as follows. The first nut is a flanged nut. 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 stopper member includes an engaging portion configured to enable a tool to be engaged therewith. A bicycle power transmission device according to an e