CN-121990099-A - Power transmission device for bicycle

Abstract

The present application relates to a power transmission device for a bicycle. Wear of the first plate and the second plate is suppressed. The coil spring is disposed in the accommodation hole of the first rotating body, and the first window of the first plate, the second window of the second plate, and the second window of the second plate. The first plate has a first contact surface and a first notch. The first contact surface is in contact with the end surface of the coil spring. The first notch is formed on the first contact surface. The second plate has a second contact surface and a second cutout portion. The second abutting surface abuts against the end face of the coil spring. The second notch is formed on the second contact surface.

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. 1. A power transmission device for a bicycle is provided with: a first rotating body having a receiving hole; a first plate having a first window portion, the first plate being configured to be relatively rotatable with respect to the first rotating body; A second plate having a second window portion, the second plate being configured to rotate integrally with the first plate, the second plate being configured such that the first rotating body is sandwiched between the second plate and the first plate in an axial direction, and A coil spring disposed in the first window portion, the second window portion, and the accommodation hole, the coil spring elastically connecting the first rotating body, the first plate, and the second plate, The first plate has a first contact surface which contacts with the end surface of the coil spring and a first notch formed on the first contact surface, The second plate has a second contact surface that contacts the end surface of the coil spring and a second cutout portion formed in the second contact surface.
2. 2. The power transmission device for a bicycle according to claim 1, wherein, The first plate has a first offset portion that is disposed radially inward of the first cutout portion and is offset toward the first rotating body side.
3. 3. The power transmission device for a bicycle according to claim 2, wherein, The second plate has a second offset portion that is disposed radially inward of the second cutout portion and is offset toward the first rotating body side.
4. 4. The power transmission device for a bicycle according to claim 2, wherein, The coil spring is not abutted against the first offset portion.
5. 5. The power transmission device for a bicycle according to claim 1, wherein, The first rotating body has a third contact surface that contacts the coil spring, and the third contact surface has no notch.

Description

Power transmission device for bicycle Technical Field The present invention relates to a power transmission device for a bicycle. Background The power transmission device for a bicycle includes a first rotating body, a first plate, and a second plate (for example, patent document 1). The first plate and the second plate are configured to rotate integrally with each other. The first rotating body, the first plate, and the second plate are elastically coupled by a coil spring. Specifically, the coil springs are disposed in the accommodation hole of the first rotating body, in the window of the first plate, and in the window of the second plate. 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 In use of the power transmission device for a bicycle, the coil springs rotate in the respective window portions, and the first plate and the second plate may be worn. The technical problem underlying the present invention is therefore to suppress wear of the first plate and the second plate. Technical scheme for solving technical problems The power transmission device for a bicycle according to the first aspect includes a first rotating body, a first plate, a second plate, and a coil spring. The first rotating body has an accommodation hole. The first plate has a first window portion. The first plate is configured to be relatively rotatable with respect to the first rotating body. The second plate has a second window portion. The second plate is configured to rotate integrally with the first plate. The second plate is configured such that the first rotating body is sandwiched between the second plate and the first plate in the axial direction. The coil spring is disposed in the first window portion, the second window portion, and the accommodation hole. The coil spring elastically connects the first rotating body, the first plate, and the second plate. The first plate has a first contact surface and a first notch. The first contact surface is in contact with the end surface of the coil spring. The first notch is formed on the first contact surface. The second plate has a second contact surface and a second cutout portion. The second abutting surface abuts against the end face of the coil spring. The second notch is formed on the second contact surface. According to this configuration, since the first cutout is formed in the first contact surface, the radially outer portion and the radially inner portion are easily deformed to follow the rotation of the coil spring with respect to the first cutout. As a result, the coil spring and the first contact surface can be restrained from rotating relative to each other, and abrasion of the first plate can be restrained. Similarly, since the second cutout portion is also formed in the second contact surface, abrasion of the second plate can be suppressed. The power transmission device for a bicycle according to the second aspect is the power transmission device for a bicycle according to the first aspect, and is configured as follows. The first plate has a first offset. The first offset portion is disposed radially inward of the first cutout portion. The first offset portion is offset toward the first rotating body. 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 second plate has a second offset. The second offset portion is disposed radially inward of the second cutout portion. The second offset portion is offset toward the first rotating body. A power transmission device for a bicycle according to a fourth aspect is the power transmission device for a bicycle according to the second or third aspect, configured as follows. The coil spring is not in contact with the first offset portion. A fifth aspect of the present invention provides the power transmission device for a bicycle according to any one of the first to fourth aspects, wherein the power transmission device is configured as follows. The first rotating body is provided with a third abutting surface. The third abutting surface abuts against the spiral spring. The first rotating body does not have a notch in the third contact surface. Effects of the invention According to the present invention, abrasion of the first plate and the second plate can be suppressed. Drawings Fig. 1 is a sectional view of a power transmission device for a bicycle. Fig. 2 is a front view of the power transmission device for a bicycle. Fig. 3 is a front view of the first rotating body. Fig. 4 is a front view of the first plate. Fig. 5 is a cross-sectional view taken along line V-V of fig. 4. Fig. 6 is a front view of the second plate. Fig. 7 is a cross-sectional view taken along line VII-VII of fig. 6. Fig. 8 is a side view of the stop member. Description of the reference numerals