Sprocket assembly with adapter

Patent metadata

Field	Value
Publication number	US-10151378-B2
Application number	US-201615058653-A
Country	US
Kind code	B2
Filing date	Mar 2, 2016
Priority date	Mar 2, 2015
Publication date	Dec 11, 2018
Grant date	Dec 11, 2018

Abstract

A sprocket assembly for a bicycle freewheel that comprises a sprocket having a central opening and an adapter constructed separately from the sprocket and adapted to be connected to the sprocket in a rotationally secure manner. The adapter comprises a central opening having an edge and a plurality of drive elements at the edge. The plurality of drive elements extend radially inwardly from the edge. The plurality of drive elements constructed to transmit torque from the sprocket to a driver on a rear wheel hub of a bicycle. A minimum radius of the central opening of the sprocket is smaller than a maximum radius of the central opening of the adapter. The minimum radius of the central opening of the sprocket is disposed on at least three locations distributed about a periphery.

First claim

The invention claimed is:

1. A sprocket assembly for a bicycle freewheel, comprising:
a sprocket having a central opening; and
an adapter constructed separately from the sprocket and adapted to be connected to the sprocket in a rotationally secure manner, the adapter comprising a central opening having an edge and a plurality of drive elements at the edge, the plurality of drive elements extending radially inwardly from the edge, the drive elements constructed to transmit torque from the sprocket to a driver on a rear wheel hub of a bicycle,
wherein a minimum radius of the central opening of the sprocket is larger than a minimum radius, and smaller than a maximum radius, of the central opening of the adapter, the minimum radius of the central opening of the sprocket disposed on at least three locations distributed about a periphery.

2. The sprocket assembly according to claim 1 , wherein the minimum radius of the central opening of the sprocket is disposed about the entire periphery.

3. The sprocket assembly according to claim 1 , wherein the sprocket is manufactured from a material which is harder than a material of the adapter.

4. The sprocket assembly according to claim 3 , wherein the adapter is manufactured from one of aluminium and glass-fibre-reinforced plastic.

5. The sprocket assembly according to claim 4 , wherein the adapter is injection moulded.

6. The sprocket assembly according to claim 1 , wherein one of the adapter and the sprocket comprises a plurality of axial recesses and the other of the adapter and the sprocket comprises a plurality of axial projections constructed to engage in the axial recesses.

7. The sprocket assembly according to claim 6 , wherein the plurality of projections are constructed to engage in the axial recesses with a press fit and the axial recesses are constructed as axial through-openings.

8. The sprocket assembly according to claim 1 , wherein the adapter and the sprocket each comprise a plurality of axial recesses, wherein the sprocket assembly further comprises a plurality of pins introduced into the axial recesses of the adapter and the sprocket so that the pins connect the adapter and the sprocket to each other in a rotationally secure manner.

9. The sprocket assembly according to claim 8 , wherein the pins are manufactured from steel and pressed into the axial recesses of the adapter and the sprocket.

10. The sprocket assembly according to claim 1 , wherein a plurality of recesses are provided at the edge of the central opening of the sprocket and the adapter is constructed as a ring of first and second peripheral portions which alternate in a peripheral direction with a basic shape of circular ring segments, wherein the second peripheral portions project beyond the first peripheral portions in a radially inwardly direction and project axially toward a side of the adapter which faces the sprocket in the state fixed to the sprocket, wherein the portions of the second peripheral portions which project beyond the first peripheral portions in a radially inwardly direction form the drive elements of the adapter and the portions of the second peripheral portions which axially project beyond the first peripheral portions are constructed to engage in the recesses of the sprocket.

11. A drive assembly for a bicycle, the drive assembly comprising:
a sprocket assembly comprising:
a sprocket having a central opening, and
an adapter constructed separately from the sprocket and adapted to be connected to the sprocket in a rotationally secure manner, the adapter comprising a central opening having an edge, a plurality of drive elements at the edge, the plurality of drive elements extending radially inwardly from the edge, the drive elements constructed to transmit torque from the sprocket to a driver on a rear wheel hub of a bicycle,
wherein a minimum radius of the central opening of the sprocket is smaller than a maximum radius, and larger than a minimum radius, of the central opening of the adapter, the minimum radius of the central opening of the sprocket disposed on at least three locations distributed about a periphery; and

a driver having a plurality of drive elements constructed to engage between the drive elements of the adapter to ensure torque transmission from the sprocket via the adapter to the driver, wherein the radial play between the driver and the sprocket is smaller than the radial play between the driver and the adapter.

12. The drive assembly according to claim 11 , wherein between the sprocket and the driver there is one of a transition fit and press fit, whilst between the adapter and the driver there is a play fit.

13. The drive assembly according to claim 11 , wherein the minimum radius of the central opening of the sprocket is disposed about the entire periphery.

14. The drive assembly according to claim 11 , wherein the sprocket is manufactured from a material which is harder than a material of the adapter.

15. The drive assembly according to claim 14 , wherein the adapter is manufactured from one of aluminium and glass-fibre reinforced plastic.

16. The drive assembly according to claim 15 , the adapter is injection moulded.

17. The drive assembly according to claim 11 , wherein one of the adapter and the sprocket comprises a plurality of axial recesses and the other of the adapter and the sprocket comprises a plurality of axial projections constructed to engage in the axial recesses.

18. The drive assembly according to claim 17 , wherein the plurality of projections are constructed to engage in the axial recesses with a press fit and the axial recesses are constructed as axial through-openings.

19. The drive assembly according to claim 11 , wherein the adapter and the sprocket each comprise a plurality of axial recesses, wherein the sprocket assembly further comprises a plurality of pins introduced into the axial recesses of the adapter and the sprocket so that the pins connect the adapter and the sprocket to each other in a rotationally secure manner.

20. The drive assembly according to claim 19 , wherein the pins are manufactured from steel and pressed into the axial recesses of the adapter and the sprocket.

21. The sprocket assembly according to claim 11 , wherein a plurality of recesses are provided at the edge of the central opening of the sprocket, and the adapter is constructed as a ring of first and second peripheral portions which alternate in a peripheral direction with a shape of circular ring segments, wherein the second peripheral portions project beyond the first peripheral portions in a radially inwardly direction and project axially toward a side of the adapter which faces the sprocket in the state fixed to the sprocket, wherein the portions of the second peripheral portions which project beyond the first peripheral portions in a radially inwardly direction form the drive elements of the adapter and the portions of the second peripheral portions which axially project beyond the first peripheral portions are constructed to engage in the recesses of the sprocket.

Assignees

• Sram De Gmbh
• Sram De Gmbh

Inventors

• Reineke Sebastian
• Braedt Henrik

Classifications

• F16H55/30

  Chain-wheels · CPC title

• B62M9/10 Primary

  involving different-sized wheels, {e.g. rear sprocket chain wheels} selectively engaged by the chain, belt, or the like {(bicycle hubs rotatably arranged on axle B60B27/023)} · CPC title

• F16H55/12 Primary

  with body or rim assembled out of detachable parts · CPC title