Patent Application
20060175155
The invention relates to a pneumatically or electromotively operated disc brake, in particular, one for a commercial vehicle, having a brake caliper which straddles a brake disc, and having at least one brake application device for applying the brake disc, wherein at least one adjusting spindle, on its side facing toward the brake disc, has a pressure piece and, for the sealing of the exit region of the adjusting spindle from the brake caliper, a bellows is connected to the latter or to parts fastened thereto.
The basic structure of such a disc brake is known, for example, from German Patent document DE 195 15 063 C2.
The disc brake, which is shown and described therein, has a brake application device having two adjusting spindles, which are displaceably mounted in the brake caliper. At the brake-disc-facing end of the two spindles there is, respectively disposed, a pressure piece. The pressure pieces support a brake pad, which, during functioning, makes contact with a brake disc.
In order to protect the interior of the brake caliper and the adjusting spindles from dirt contamination, in the respective exit region of the adjusting spindle from the brake caliper there is disposed a bellows, which is fastened to a closing plate by which the brake caliper is closed off. In this regard, the closing plate is a constituent part of the brake caliper, to which the bellows can also be directly fastened if no closing plate is provided. On the other hand, the bellows is fastened to the pressure piece, which, additionally, is directly connected to the adjusting spindle.
The disc brakes which are usually fitted in commercial vehicles are subjected during operation, and under the frictional heat which is generated, to a considerable thermal load, which, emanating from the brake pad, continues via the connected metal pressure pieces, and the adjusting spindles connected thereto, to inside the brake caliper and on to relevant parts of the brake application device.
Equally, the bellows fastened to the pressure piece is subjected to heat, whereby the working life of the bellows, which consists of a plastic or a similar material, is reduced.
The not inconsiderable thermal loading of those functional parts precludes a sought-after optimized service life, so that relatively short maintenance intervals are necessary in order to permanently ensure operating reliability.
Of course, not only the maintenance and service work per se, but also the load-dictated necessary replacements of components, are connected with considerable costs, both in terms of their procurement and in terms of the assembly and disassembly, as well as the necessary downtime of the vehicle.
An aspect of the present invention is therefore to refine a disc brake of the above-mentioned type such that its service time interval is increased and repair costs are consequently lowered.
This aspect may be achieved by a disc brake, for a commercial vehicle, having a brake caliper which straddles a brake disc, and having at least one brake application device for applying the brake disc, wherein at least one adjusting spindle, on its side facing toward the brake disc, has a pressure piece and, for the sealing of the exit region of the adjusting spindle from the brake caliper, a bellows is connected to the latter or to parts fastened thereto. Between the pressure piece and the adjusting spindle, a heat shield is connected directly or indirectly to the bellows, which heat shield covers at least that end face of the adjusting spindle which faces toward the pressure piece.
According to the invention, for forming a thermal break between the pressure piece and the adjusting spindle, a heat shield is connected directly or indirectly to the bellows. The heat shield covers at least that end face which faces toward the pressure piece. A direct contact between the pressure piece and the adjusting spindle thus no longer exists, so that nor, any longer, does an excessive heat transfer take place from the pressure piece to the adjusting spindle.
Correspondingly, the heating of adjoining components, such as, for example, a cross member in which the adjusting spindle is guided, as well as of the brake application device, is thereby actively reduced. Equally, a heating of the interior of the brake caliper and of the adjoining components through radiant heat is prevented.
Thus, the invention helps significantly to increase the service life of the disc brake, i.e. to lengthen the repair intervals and inspection intervals.
This, of course, yields a cost reduction compared with a disc brake according to the prior art, to which reduced assembly and material costs also contribute.
The heat shield consists of a material having lower heat conductivity than the other material of the pressure pieces and can be applied as a coating to a pot element, which is fastened in an axially secure manner to the adjusting spindle, which, however, is held in a freely rotatable manner in the pot element. This type of fastening may be realized by a circumferential annular groove in the adjusting spindle, in which the pot element, by virtue of an appropriate add-on molding, positively engages.
In place of a coating of the pot element, i.e. a composite coating, the heat shield may also be designed as a separate part, for example in the form of a plate covering the end face of the adjusting spindle. Where appropriate, it may also adjoin side regions. The plate is disposed virtually between the pot element and the adjusting spindle.
The pot element, expediently configured as a sheet-metal molding, is connected to the bellows by surrounding injection molding, to be precise circumferentially. Since the bellows, on the other hand, is fastened either directly to the brake caliper or, for example, to a closing plate, the exit region of the adjusting spindle from the brake caliper is hermetically sealed, so that no dirt particles can get into the interior of the brake caliper or onto the adjusting spindle and the threads thereof.
As a result of the direct binding of the bellows to the pot element, which, as mentioned, is connected to the adjusting spindle, a hitherto necessary secondary seal and associated components can be dispensed with. Consequently and as a result of the simple, yet very effective nature of the securement of the bellows on the adjusting spindle through binding to the pot element, an economical production and an inexpensive assembly and disassembly are obtained. The pot element/heat shield unit can here be used in different embodiments of the disc brake. Thus, the assigned pressure piece can be connected to the pot element, for example. It is also contemplated, however, to use the pot element with heat shield in a design in which the pressure piece is an integral component of the brake pad or of a brake lining carrier.
The securement of the protective-plate-forming pot element to the bellows in the sense of the surrounding injection molding may be realized, for example, with a suitable elastomer, preferably a silicone rubber. In any event, the now no longer direct binding of the bellows to the pressure piece has the effect that the bellows, too, is exposed to a lesser thermal load, which, inter alia, means that the bellows too may be used throughout several changes of the brake pads, thereby also, of course, producing cost benefits.
The heat shield may be placed as a separate plate loosely between the pot element and the facing end face of the adjusting spindle. There is also the possibility, however, of connecting the heat shield as a separate part to the pot element or the adjusting spindle, for which the elastomer is suitable, which then serves virtually as a connecting mechanism.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
An illustrative embodiment of the invention is described below with reference to the appended drawings, in which:
In
Disposed on both sides of the brake disc 3 are brake pads 4 (here, represented only on one side). Here, one brake pad is shown fastened to or bearing against a pressure piece 5, by which the assigned brake pad 4 can be pressed against the brake disc 3.
The pressing of the brake pad against the disc is done by a brake application device 2, which is operated by a rotary lever and is connected to at least one adjusting spindle 10 supporting a respective pressure piece 5 and guided in an axially movable manner in the brake caliper 1.
Only one pressure piece 5, together with the associated components, is represented and described herein. A preferred construction, however, has two pressure pieces 5 on a respective side of the disc.
In the present illustrative embodiment, the brake caliper 1 is largely closed off, on its side facing toward the brake disc 3, by a closing plate 7, which is pierced in the exit region of the adjusting spindle 10.
For sealing the exit region of the adjusting spindle 10 from the brake caliper 1, a bellows 9 connected to the closing plate 7 is respectively provided, which, on the other hand, is connected to the adjusting spindle 10.
In the case of a configuration of the brake caliper 1, wherein the closing plate 7 is dispensed with, then the bellows 9 are fastened directly to the brake caliper 1, e.g. pressed in place.
In
The heat shield 6 according to
The heat shield 6 is covered and held by a pot element 8, which engages positively in an annular groove 11 in the adjusting spindle 10 such that it is axially secured, yet the adjusting spindle 10 is freely rotatable.
The bellows 9 are connected to the pot element 8, preferably through encapsulating injection molding using a suitable material, for example an elastomer and in this case, preferably, silicone rubber.
The opposite, in this regard free edge of the bellows 9 is fixedly connected to the closing plate 7 or, in another case, directly to the brake caliper 1, so that both the bellows 9 and the pot element 8 are held in a torsionally secure manner relative to the adjusting spindle 10.
Bearing against that side of the pot element 8 which lies opposite the adjusting spindle 10 is the pressure piece 5, which can be fixedly connected to the pot element 8 or, if the pressure piece 5 is an integral component of the brake pad 4, is only operatively connected thereto, i.e. in a loosely adjacent manner.
In
In any event, the bellows 9 is now no longer directly fastened to the pressure piece 5, as in the state of the art, but rather indirectly to the adjusting spindle 10, whereby heat transfer emanating from the pressure piece 5 is actively prevented.
The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 103 31 929.8 | Jul 2003 | DE | national |
This application is a Continuation of PCT Application No. PCT/EP2004/007705, filed on Jul. 13, 2004, which claims priority of German Application No. 103 31 929.8, filed Jul. 15, 2003, the disclosure of which is expressly incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP04/07705 | Jul 2004 | US |
| Child | 11331059 | Jan 2006 | US |
