US-12617233-B2 - Bicycle wheel hub

US12617233B2US 12617233 B2US12617233 B2US 12617233B2US-12617233-B2

Abstract

A freewheel hub for a bicycle is presented. The freewheel hub may include a hub axle, a hub sleeve which is mounted rotatably on the hub axle, and a driver which is mounted rotatably on the hub axle and can be connected to at least one sprocket arrangement. A freewheel device may be arranged between the hub sleeve and the driver. The free wheel device may include a first clutch ring, which is coupled or couplable to the hub sleeve in a torque-transmitting manner, a second clutch ring, which is coupled or couplable to the driver in a torque-transmitting manner. The two clutch rings have mutually facing axial toothings and a preload device which is designed and arranged to preload the two clutch rings axially towards one another, wherein the preload device has a spring arrangement with at least one spring element made of a plastic with a cellular structure.

Inventors

Joachim Goebel

Assignees

SRAM DEUTSCHLAND GMBH

Dates

Publication Date: 20260505
Application Date: 20211015
Priority Date: 20201016

Claims (14)

1 . A freewheel hub for a bicycle, comprising: a hub axle; a hub sleeve which is mounted rotatably on the hub axle; a driver which is mounted rotatably on the hub axle and can be connected to at least one sprocket arrangement; and a freewheel device arranged between the hub sleeve and the driver, comprising: a first clutch ring, which is coupled or couplable to the hub sleeve in a torque-transmitting manner, a second clutch ring, which is coupled or couplable to the driver in a torque-transmitting manner, wherein the first clutch ring and the second clutch ring have mutually facing axial toothings, and a single preload device which is arranged to preload, in a single axial direction, the two clutch rings axially towards one another, wherein the single preload device has a spring arrangement with at least one spring element that includes a plastic with a cellular structure, the spring element having an arcuate portion, the convex side of which is configured to press against one of the clutch rings in the single axial direction in order to preload the two clutch rings against one another.
2 . The freewheel hub according to claim 1 , wherein the spring element includes a polyurethane-based plastic.
3 . The freewheel hub according to claim 1 , wherein the spring arrangement includes a plurality of spring elements.
4 . The freewheel hub according to claim 1 , wherein the plurality of spring elements are of a same type and are arranged distributed around the circumference of the hub axle.
5 . The freewheel hub according to claim 1 , wherein the arcuate portion is in the form of a strip portion with substantially constant width and thickness.
6 . The freewheel hub according to claim 1 , wherein the spring arrangement is configured such that, although the spring arrangement is deformed when a contact pressure of 0.2 N to 0.5 N is applied to the spring arrangement in the axial direction, the cellular structure of the plastic is not compressed.
7 . The freewheel hub according to claim 1 , further comprising a plurality of separately formed spring elements of a same type, which together form the spring arrangement.
8 . The freewheel hub according to claim 7 , wherein each spring element is in the form of a D ring or formed in the shape of an arc with angled-away longitudinal ends.
9 . The freewheel hub according to claim 7 , wherein the spring elements are inserted into corresponding depressions formed in an axial surface of the hub sleeve or an axial surface of the driver.
10 . The freewheel hub according to claim 1 , having a plurality of spring elements of the same type, which are connected to one another in one piece and preferably in the form of a cohesive strip which forms the spring arrangement.
11 . The freewheel hub according to claim 10 , wherein the plurality of spring elements are distributed around the hub axle in the circumferential direction, wherein the preload device also has a retaining ring, which is designed to fix the positions of the spring elements relative to one another.
12 . The freewheel hub according to claim 11 , wherein the retaining ring comprises an annular base and a plurality of retaining elements which are distributed around the circumference of the base, protrude radially from said base, cover the spring arrangement axially on one side in certain portions and preferably engage around the spring arrangement radially from the inside and outside.
13 . The freewheel hub according to claim 12 , wherein the preload device also comprises a cover ring, which can be mounted on the retaining ring such that the spring arrangement is received at least in certain portions between the retaining ring and the cover ring and, together with the retaining ring and the cover ring, forms a solidly cohesive assembly.
14 . A preload device for a freewheel hub, comprising: a spring arrangement with at least one spring element, wherein the at least one spring element includes a plastic with a cellular structure, and wherein the spring arrangement is arranged to preload, in a single axial direction, two clutch rings axially towards one another.

Description

This application claims priority to, and/or the benefit of, German patent application DE 10 2020 127 381.9 filed Oct. 16, 2020, the contents of which are incorporated herein in their entirety. FIELD OF INVENTION The present invention relates to a freewheel hub for a bicycle that comprises a hub axle, a hub sleeve which is mounted rotatably on the hub axle, a driver which is mounted rotatably on the hub axle and can be connected to at least one sprocket arrangement, and also a freewheel device which is arranged between the hub sleeve and the driver BACKGROUND An A freewheel hub is known from the document DE 198 47 73 A1, for example. Said document describes a freewheel hub in which the preload device is formed by two helical compression springs made of steel. Owing to manufacturing-related restrictions in the production of steel springs, in particular in terms of the winding ratio, said steel springs can, however, only be used for clutch rings with a limited diameter and consequently a limited number of clutch teeth. For this reason, only relatively large angles of engagement can be realized, for instance 20° to 15°. It is also the case that the forces acting on the clutch teeth are relatively large on account of the limited diameter, this leading to rapid wear. Furthermore, the operating noises in the case of freewheels with steel springs are generally very loud. As an alternative, freewheel hubs with magnetic preload devices are known, for example from DE 10 2015 009 143 A1. However, these have a considerably more complex and thus more cost-intensive structure and require high precision and narrow tolerances in comparison with the freewheel hubs with mechanical preload devices. Moreover, the force applied to the clutch rings by the magnets is not distributed uniformly around the circumference of the hub axle, but acts in a very punctiform manner. At relatively high speeds and in particular during fast suspension deflection movements of the rear wheel on a full-suspension bicycle (MTB fully), the clutch rings start to perform oscillating movements, the result of which is that sometimes only individual teeth of the axial toothings engage, causing them to become damaged. As the operating time increases, this can continue up to the total failure of the entire freewheel. SUMMARY In an embodiment, a freewheel hub for a bicycle is presented. The freewheel hub may include a hub axle, a hub sleeve which is mounted rotatably on the hub axle, and a driver which is mounted rotatably on the hub axle and can be connected to at least one sprocket arrangement. A freewheel device may be arranged between the hub sleeve and the driver. The free wheel device may include a first clutch ring, which is coupled or couplable to the hub sleeve in a torque-transmitting manner, a second clutch ring, which is coupled or couplable to the driver in a torque-transmitting manner. The two clutch rings have mutually facing axial toothings and a preload device which is designed and arranged to preload the two clutch rings axially towards one another, wherein the preload device has a spring arrangement with at least one spring element made of a plastic with a cellular structure. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be discussed in more detail below on the basis of embodiments and with reference to the appended drawings, in which: FIG. 1 shows a first exemplary embodiment of a freewheel in a longitudinal sectional view, FIG. 2 shows an enlargement of a detail of the region denoted by II in FIG. 1, FIG. 3 shows an exploded illustration of the preload device of the freewheel hub from FIG. 1, FIG. 4 shows a perspective view of the preload device from FIG. 3 in the assembled state, FIG. 5 shows a side view of the spring arrangement of the preload device from FIG. 3 before being placed into the retaining ring, FIG. 6 shows a plan view of the bottom side of the subject matter of FIG. 5, FIG. 7 shows an enlargement of a detail of the region denoted by VII in FIG. 5, FIG. 8 shows an exploded illustration of essential components of a second exemplary embodiment of a freewheel hub, and FIG. 9 shows an exploded illustration of essential components of a third exemplary embodiment of a freewheel hub. DETAILED DESCRIPTION OF THE DRAWINGS A freewheel device may include a first clutch ring, which is coupled or couplable to the hub sleeve in a torque-transmitting manner, and a second clutch ring, which is coupled or couplable to the driver in a torque-transmitting manner, wherein the two clutch rings have mutually facing axial toothings. Furthermore, the freewheel device may include a preload device which is designed and arranged to preload the two clutch rings axially towards one another, wherein the preload device has a spring arrangement with at least one spring element. A freewheel of this type is also referred to as an axial freewheel or ratchet freewheel. Against this background, an object of the present invention is to improve the freewh