CN-121990097-A - Power transmission device for bicycle
Abstract
A power transmission device for a bicycle capable of stably performing caulking work. The crank arm rotates integrally with the first rotating body. The first rotating body has a hub portion and a flange portion. The hub portion extends in an axial direction. The flange portion extends radially outward from the hub portion. The crank arm has a mounting portion and an arm main body portion. The mounting portion is mounted to the hub portion. The arm body portion extends radially outward from the mounting portion. The mounting portion has a mounting body portion and a distal end portion. The mounting body portion is in contact with the hub portion in the axial direction. The front end portion extends in the axial direction from the mounting body portion. The front end portion has an outer diameter smaller than an outer diameter of the mounting body portion. The front end is riveted to the hub. The mounting body portion has an outer diameter greater than an outer diameter of the hub portion.
Inventors
- HARIMA KENJI
- OSHIMA HIROSHI
Assignees
- 爱思帝股份有限公司
Dates
- Publication Date
- 20260508
- Application Date
- 20251105
- Priority Date
- 20241106
Claims (5)
- 1. A power transmission device for a bicycle is provided with: A first rotating body; a second rotating body configured to be rotatable relative to the first rotating body; An elastic member elastically connecting the first rotating body and the second rotating body, and A crank arm integrally rotated with the first rotating body, The first rotating body has a hub portion extending in an axial direction and a flange portion extending radially outward from the hub portion, The crank arm has an attachment portion attached to the hub portion and an arm body portion extending radially outward from the attachment portion, The mounting portion has: a mounting body portion axially abutting the hub portion, and A distal end portion extending in an axial direction from the mounting body portion, having an outer diameter smaller than an outer diameter of the mounting body portion, and being swaged to the boss portion, The mounting body portion has an outer diameter greater than an outer diameter of the hub portion.
- 2. The power transmission device for a bicycle according to claim 1, wherein, The hub portion has a cylindrical hub main body portion extending in an axial direction and a cylindrical small diameter portion having an inner diameter smaller than an inner diameter of the hub main body portion, The tip end portion of the mounting portion is swaged to the small diameter portion.
- 3. The power transmission device for a bicycle according to claim 2, wherein, The hub portion has: a plurality of protruding parts extending axially on the inner peripheral surface of the small diameter part, and And a plurality of relief portions formed at least one end portion in an axial direction of each of the protruding portions.
- 4. The power transmission device for a bicycle according to claim 1, wherein, The power transmission device for a bicycle further comprises a fastening member, The second rotating body has: A first plate disposed on a first side in an axial direction with respect to the flange portion, and A second plate disposed on a second side in the axial direction with respect to the flange portion, The fastening member detachably fastens the first plate and the second plate, The arm main body portion is configured not to overlap with the fastening member when viewed in the axial direction.
- 5. The power transmission device for a bicycle according to claim 4, wherein, The fastening member has: a stopper portion disposed between the first plate and the second plate; a first screw part arranged at a first side in the axial direction relative to the first plate, and The second screw portion is disposed on a second side in the axial direction with respect to the second plate.
Description
Power transmission device for bicycle Technical Field The present invention relates to a power transmission device for a bicycle. Background Patent document 1 discloses a power transmission device for a bicycle. The power transmission device for a bicycle includes a first rotating body and a second rotating body. The first rotating body and the second rotating body are elastically coupled by a coil spring. The crank arm is mounted to the hub of the first rotating body. Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2024-084007 Disclosure of Invention Technical problem to be solved by the invention The crank arm is attached to the hub of the first rotating body by caulking. The present invention provides a power transmission device for a bicycle, which can stably perform riveting processing. Technical scheme for solving technical problems The power transmission device for a bicycle according to the first aspect includes a first rotating body, a second rotating body, an elastic member, and a crank arm. The second rotating body is configured to be rotatable relative to the first rotating body. The elastic member elastically connects the first rotating body and the second rotating body. The crank arm rotates integrally with the first rotating body. The first rotating body has a hub portion and a flange portion. The hub portion extends in an axial direction. The flange portion extends radially outward from the hub portion. The crank arm has a mounting portion and an arm main body portion. The mounting portion is mounted to the hub portion. The arm body portion extends radially outward from the mounting portion. The mounting portion has a mounting body portion and a distal end portion. The mounting body portion is in contact with the hub portion in the axial direction. The front end portion extends in the axial direction from the mounting body portion. The front end portion has an outer diameter smaller than an outer diameter of the mounting body portion. The front end is riveted to the hub. The mounting body portion has an outer diameter greater than an outer diameter of the hub portion. According to this configuration, since the outer diameter of the mounting body portion is larger than the outer diameter of the boss portion, the mounting body portion serves as a base when the distal end portion of the mounting portion is swaged to the boss portion, and the swaging process for swaging the distal end portion to the boss portion can be stably performed. The power transmission device for a bicycle according to the second aspect is configured as follows in the power transmission device for a bicycle according to the first aspect. The hub portion has a hub main body portion and a small diameter portion. The hub body portion extends in an axial direction. The hub main body portion is cylindrical. The small diameter portion is cylindrical. The small diameter portion has an inner diameter smaller than an inner diameter of the hub main body portion. The front end of the mounting portion is riveted to the small diameter portion. A power transmission device for a bicycle according to a third aspect is the power transmission device for a bicycle according to the second aspect, which is configured as follows. The hub portion has a plurality of protruding portions and a plurality of relief portions. Each of the protruding portions extends in the axial direction on the inner peripheral surface of the small diameter portion. Each relief portion is formed at least one end portion in the axial direction of each protruding portion. A power transmission device for a bicycle according to a fourth aspect is the power transmission device for a bicycle according to any one of the first to third aspects, further comprising a fastening member. The second rotating body has a first plate and a second plate. The first plate is disposed on a first side in an axial direction with respect to the flange portion. The second plate is disposed on a second side in the axial direction with respect to the flange portion. The fastening member detachably fastens the first plate and the second plate. The arm body portion is configured not to overlap with the fastening member when viewed in the axial direction. A power transmission device for a bicycle according to a fifth aspect is the power transmission device for a bicycle according to the fourth aspect, configured as follows. The fastening member has a stopper portion, a first screw portion, and a second screw portion. The stop portion is disposed between the first plate and the second plate. The first screw portion is disposed on a first side in an axial direction with respect to the first plate. The second screw portion is disposed on a second side in the axial direction with respect to the second plate. Effects of the invention According to the present invention, the caulking process can be stably performed. Drawings Fig. 1 is a sectional view o