Patent Application
20230375050
The invention relates to a brake-application device of a disc brake for a utility vehicle.
By means of such a brake-application device, which is a constituent part of a disc brake, brake pads can be pressed against a vehicle-side brake disc in a braking situation.
In this case, the brake-application device is actuated pneumatically or electromechanically with the aid of a pivotable brake lever which is supported, for the one part, on an inner wall of a brake caliper, and, for the other part, on a displaceable bridge, for which purpose there is arranged a roller bearing assembly in the form of a roller which is axially and radially secured between the brake lever and the bridge.
For mounting of the roller, a bearing shell is formed in the brake lever and is coated with a suitable plastic such that what is known as a DU bearing assembly is produced.
A correspondingly modified shaped part is in turn attached to the bridge for mounting of the roller, said shaped part moreover serving to radially and axially secure the roller and serving, by way of integrally formed projections, for example tabs or the like, as cage return guide for the cages of rolling bearings, by means of which the brake lever is mounted on the inner wall of the brake caliper in a smooth-running manner. Such a brake-application device is known from DE 103 07 734 B3.
In driving operation, however, it has been found that the roller has hitherto not been sufficiently secured against axial displacement, with the result that breakage of the tabs may occur. This has the possible consequence of a failure of the brake that cannot be identified from the outside, which of course represents an unacceptable safety risk.
Moreover, the freely rotatable mounting of the roller frequently leads to the abrasive removal of particles which ingress into the DU bearing of the brake lever, which in particular adversely affects the service life of the DU bearing assembly.
To remedy this, DE 10 2014 108 500 A1 proposes that the roller be held on the bridge so as to be secured against rotation and displacement. To this end, shaped regions which correspond to one another are provided on the bridge and the roller, for example in the form of flattened portions on the roller which bear against support surfaces of the bridge.
This construction has proven successful in terms of function. However, problems may arise during the assembly of the disc brake, in particular of the brake-application device, since the roller, as an individual part, is present as a loose part prior to the assembly, which makes the assembly more difficult insofar as a fixing prior to a final position is possible only with corresponding manufacturing outlay, i.e. an assembly aid.
In addition, the configuration both of the roller and of the bridge also becomes relatively complex, since the flattened portions of the roller and the support surfaces of the bridge are of planar configuration, which is possible only with a relatively complex machining operation.
The invention is based on the object of further developing a brake-application device of the generic type such that its service life is improved using structurally simple means and its assembly becomes easier.
This object is achieved by means of a brake-application device having the features of the independent claim.
The configuration of the brake-application device according to the invention in such a way that the at least one roller is virtually connected to the bridge by a securing element, a fixing of the roller, in relation to the bridge, in terms of an axial direction, a radial direction and a direction of rotation is ensured not only in an installed position of the brake-application device but also prior to installation in a brake caliper. That is to say that the bridge and the roller may be preassembled as a structural unit and be inserted without it being necessary to employ particular assembly measures to install the arrangement of the roller, said arrangement being known from the prior art and being loose in relation to the bridge.
Since disc brakes, the essential functional component of which is a brake-application device, are produced as series products in large quantities, particular importance is attached to this significant simplification of assembly which is possible by way of the configuration according to the invention, especially with regard to the minimization of costs.
In addition, the invention affords the advantage that the use of hitherto known shaped parts which are fastened to the bridge can be dispensed with, which also contributes to cost optimization.
In this context, it should also be noted that it is now possible to dispense with the use of a hardened steel for the manufacturing of the roller, which has up to now arisen from the steel/steel friction pairing between the shaped part in the form of a bearing shell and the roller.
The at least one securing element is held on the bridge and on the roller in a positively locking or frictionally locking manner, wherein, according to a further concept of the invention, the use of a clamping sleeve which is plugged both into a bore in the bridge and into a bore in the roller and which is held therein in a frictionally locking manner has proven to be particularly advantageous.
Such clamping sleeves are commercially available as standard parts and are therefore particularly inexpensive. For tolerance compensation, one of the bores, that is to say the bore in the bridge or the bore in the roller, may be in the form of an elongate hole in small dimensions.
In principle, however, the introduction of the bores is likewise very easy and significantly more inexpensive to produce than the flattened portions of the roller and of the bridge that are described with respect to the prior art.
Instead of clamping sleeves, dowel pins may also be inserted into the correspondingly prepared bores, these dowel pins also being held in the bridge and/or in the roller in a frictionally locking manner.
As a further embodiment variant of the securing elements, eyelets may be provided on the bridge, into which eyelets two coaxially oriented rollers which are arranged with a spacing to one another are pressed as roller bearing assembly by way of their mutually averted ends. This spacing of the rollers to one another, that is to say the intermediate space formed, is dimensioned such that the rollers can be plugged in without any problems.
The eyelets are expediently formed integrally on the bridges which are composed of cast iron. This embodiment variant also ensures a more secure hold, that is to say that the rollers are secured against rotation and displacement.
Furthermore, the securing element may consist of a sheet-metal piece which is pressed both into a groove of the bearing point of the bridge and into a groove of the roller, this sheet-metal piece extending in a pivoting direction of the brake lever.
Further advantageous configurations of the invention are characterized in the dependent claims.
Exemplary embodiments of the invention will be described below on the basis of the appended drawings.
A disc brake for a utility vehicle according to the prior art is illustrated in section in
Arranged in the brake caliper 1 is a brake-application device 2 by means of which brake pads 4 can be pushed against the brake disc 3 in the event of a braking situation triggered via a preferably pneumatically actuated brake cylinder.
The brake-application device 2 in this case engages with brake plungers (not illustrated) which are arranged parallel and with a spacing to one another in a bridge 8 and which are in the form of actuating spindles.
A brake lever 5 of the brake-application device 2 is operatively connected to the brake cylinder 6 and can, when actuated, pivot in the direction of the brake disc 3 about a roller 9 which runs parallel to the plane of the brake disc 3.
On the side opposite to the roller 9, the brake lever 5 bears against rolling bodies 11 which are each held in a cage and which are supported, for the one part, on the brake lever 5 which is in the form of an eccentric 7 in this region, and, for the other part, on an inner wall of the brake caliper 1.
The roller 9, as a constituent part of a roller bearing assembly, serves as rotary bearing for the brake lever 5 and lies in a bearing shell 10 of the eccentric 7. In this case, the cross section of the bearing shell 10 is adapted to the cross-sectional contour of the roller 9 in the same way as a concave channel 12 in which the roller 9 lies.
The bridge 8 is depicted as a detail of the brake-application device 2 in
In the variant shown in
A further configuration of the brake-application device 2 according to the invention is depicted in
Lastly,
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2020 124 690.0 | Sep 2020 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/073618 | 8/26/2021 | WO |
