PRIORITY

This application claims priority to, and/or the benefit of, German patent application DE 10 2019 002 638.1, filed on Apr. 10, 2019, the contents of which are included by reference herein in their entirety.

BACKGROUND

The present disclosure relates to a torque transmission assembly for a bicycle, and to a method for producing a torque transmission assembly.

In the drivetrain and at other points on a bicycle, for example in the region of disc brakes, torque needs to be transmitted. The amount of torque to be transmitted can sometimes turn out to be very high. Thus, the drive torque or braking torque that arise in the region of the hubs in the case of bicycles can easily reach medium to high three-digit newton meter ranges. High torque also arises in the region of the bottom bracket at the connection between the crank and chainring, depending on the rider's weight and position.

These torques result in correspondingly high forces to be transmitted. The torques are particularly high at the interfaces between rotationally loaded assemblies, such as: at the transition between a sprocket and a spider, at the transition between a bicycle crank and a chainring spider arranged there, at the transition between a sprocket or sprocket spider and an associated freewheel driver of a rear wheel, at the transition between a brake disc and a spider carrying the brake disc, or between the brake disc spider and bicycle hub.

At these interfaces, the forces to be transmitted are naturally greater when the diameter of the corresponding interface between the respective rotationally loaded assemblies is smaller. Accordingly, it is generally known to use softer and/or thinner materials for components arranged radially further out, for example spiders or sprockets, since correspondingly lower forces and loads arise radially further out. Similarly, correspondingly harder and/or thicker materials are used for components arranged radially further in, for example for the radially internal regions of spiders.

High loads and correspondingly high demands exist in particular in the region of such transitions between components or component regions in which thinner and/or softer components adjoin thicker and/or harder components, or in which such components are intended to be connected together.

The document EP3064425B1 discloses, for example in FIG. 1d, a torque transmission assembly in the form of a bicycle sprocket with an adapter. Therein, the material of the sprocket is comparatively thin, while the adapter, which is produced separately and from a different material from the sprocket, has a relatively high material thickness compared with the sprocket. In this document, the adapter is connected to the sprocket in that cylindrical rivet protrusions that are arranged on the adapter around the circumference of an imaginary pitch circle are pressed into corresponding bores in the sprocket, wherein the sprocket bores are arranged around the same pitch circle circumference as the protrusions on the adapter.

In that case, however, during production, the problem can arise that the diameter of the pitch circle at the circumference of which the rivet protrusions of the adapter are arranged differs unintentionally from that pitch circle diameter at the circumference of which the bores in the sprocket are arranged. This can occur for example on account of manufacturing tolerances of the sprocket and/or of the adapter, or for example on account of warpage or contraction that can arise for instance during the hardening of the adapter.

In any case, such differences in the pitch circle diameter of the sprocket and/or adapter, on the circumferences of which the rivet protrusions and bores, respectively, are arranged, or any roundness errors of one or both of these pitch circles can result in the connection between the sprocket and adapter not achieving the desired strength. Similarly, difficulties in the form of excessively high press-in forces during the pressing together of the sprocket and adapter can arise, and ultimately undesired radial distortion forces that result therefrom can cause warpage of the unit made up of the sprocket and adapter, and thus correspondingly impaired true running of the sprocket. All of this can increase the production costs or result in more scrap during production.

SUMMARY

According to one embodiment, a torque transmission assembly for a bicycle includes an adapter device having support arms extending with a radial direction component, and a driving body rigidly connectable to the adapter device in a torque transmitting manner, the driving body including complementary support cutouts of complementary position and shape to the support arms. The support arm of are received in the support cutouts of the driving body, forming a press fit. The press fit of the support arm and the support cutout have two fitting planes which are parallel to one another and to an imaginary plane containing the axis of rotation of the torque transmission assembly. A clearance exists between the support arm and support cutout along the radial direction component.

According to one embodiment, a method for producing a torque transmission assembly includes producing a driving body and an adapter device such that first fitting surfaces of support arms form an interference fit at least in the tolerance zone range S to Z with second fitting surfaces of driving body support cutouts. Next, positioning the adapter device and the driving body axially on top of each other along an assembly axis of rotation such that the support arms cover the driving body support cutouts, and next pressing the adapter device and the driving body together along the assembly axis of rotation, with a chip formation at the first and the second fitting surfaces.

