Brake holder for a floating-caliper disk brake with a brake pad guide spring

The present invention relates to a brake holder of a floating-caliper disc brake for motor vehicles at which brake pads arranged on either side of an associated brake disc are displaceably mounted. To ensure ease of displaceability a brake pad guide spring is provided that extends between the brake holder and the brake pads. For ease of mountability of both the brake pads and the brake pad guide spring, it is arranged for that the brake pad guide spring is mountable on the brake holder in a generally radial direction and is locked at the brake holder in both radial and axial directions by means of at least one fixing clamp, and at least one spring arm is designed at the brake pad guide spring and fixes at least one brake pad under spring bias in position on the brake holder in a clearance-free manner. These provisions not only improve the mountability of a brake of this type but also the rattle-free resilient arrangement of the brake pads.

TECHNICAL FIELD

The present invention relates to a brake holder of a floating-caliper disc brake for motor vehicles at which brake pads arranged on either side of an associated brake disc are displaceably mounted. To ensure ease of displaceability a brake pad guide spring is provided that extends between the brake holder and the brake pads.

BACKGROUND OF THE INVENTION

DE 100 50 013 A1 discloses a disc brake of this type comprising a brake holder fixed to the vehicle. In this application, the brake pads are guided in the brake holder in an axially displaceable manner, and a slide spring element is placed between the brake holder and the brake pads for greater ease of displaceability, through which element at least one brake pad is locked radially at the brake holder. The sliding spring element is attached to the brake holder so as to be held captive in a radial direction. The geometrical shape of the slide spring element is adapted to a guide profile in the brake holder that is also used for the displaceable accommodation of the brake pads. The result is a form-fit attachment of the slide spring element on the brake holder. Such a form-fit connection of slide spring element and brake holder implies, however, a poor or complicated mountability of the slide spring element on the brake holder. In addition, the simultaneous resilient arrangement of the brake pad by means of the slide spring element is insufficient so that a principally rattle-free guiding of the brake pads cannot be safeguarded.

Based on the above, an object of the invention is to devise a generic brake holder with a corresponding brake pad guide spring, the brake holder facilitating the assembly of the individual components and additionally enabling a comfortable resilient arrangement of an associated brake pad in the brake holder by means of the brake pad guide spring.

BRIEF SUMMARY OF THE INVENTION

This object is achieved by a brake holder of a floating-caliper disc brake for motor vehicles comprising a corresponding brake pad guide spring. The brake holder comprises axially extending holder arms at which associated brake pads are displaceably arranged, said brake pads being arranged on either side of a brake disc and mountable in the brake holder in a radial direction. For ease of displaceability of the brake pads in the brake holder, at least one brake pad guide spring is provided, which is arranged between the brake holder and the brake pads. In a novel manner, the brake pad guide spring is mountable on the brake holder in a generally radial direction and locked at the brake holder in both radial and axial directions by means of at least one fixing clamp. To this end, the brake pad guide spring is simply shifted into a corresponding portion of the brake holder which is simultaneously provided for the displaceable brake pad guide, with at least one fixing clamp becoming locked at the brake holder. The locking engagement by means of the fixing clamp is used to fix the brake pad guide spring safely on the brake holder, although it is easy to mount. For the additionally rattle-free brake pad guide, the brake pad guide spring includes at least one spring arm that fixes at least one brake pad under spring load relative to the brake holder in a clearance-free manner.

A favorable embodiment of the brake holder with brake pad guide spring is achieved in that the fixing clamp is locked at a correspondingly configured radial undercut of the brake holder. Such an undercut is preferably designed within the guiding portion of the brake pads on the brake holder. This allows shaping the undercut while machining the guiding portion for the brake pads what is anyway necessary. In addition, it is expedient to provide axially effective fixing clamps. This allows fixing the locked brake pad guide spring at the brake holder both in radial and axial directions. To further improve the attachment of the brake pad guide spring it can be suitable to make the locking engagement non-detachable so that the brake pad guide spring, after its locking engagement, cannot be removed from the brake holder without being destroyed. An alternative attachment of the brake pad guide spring is carried out by way of an appropriate projection on the brake holder at which the fixing clamp is locked, or which the fixing clamp embraces. Depending on the case of application, this arrangement allows attaching the brake pad guide spring by means of one single fixing clamp in axial and radial directions.

In a preferred variant of the brake holder with a brake pad guide spring, the brake pad guide spring includes a first portion for radial locking engagement of the brake pad at the spring arm, said portion forming a radial stop for the mounted brake pad. After the radial mounting of the brake pad in the brake holder with brake pad guide spring, the brake pad is thus prevented from lifting radially out of the guiding portion of the brake holder.

To facilitate the design of a rattle-free overall arrangement of the floating-caliper disc brake, it can be provided that the brake pad guide spring locked at the brake holder abuts in a clearance-free manner at least on guiding surfaces of the brake holder that are used for the displaceable arrangement of the brake pads on the brake holder.

Another advantageous variant of a brake pad guide spring is achieved in that a mounting ramp is provided at the spring arm for facilitating radial mounting of the brake pads. This simplifies the radial introduction of the brake pads into the brake holder, thereby preventing the brake pads from jamming in the brake holder.

In a suitable development of the brake holder with brake pad guide spring, the spring arm bears under preload against an inclined abutment surface of the brake pad, when the brake pad is mounted, and thus clamps the brake pad with respect to the brake holder in a clearance-free manner. This allows reliably preventing the undesirable development of rattle noises. It proves favorable in this context to provide a tangentially active stop for the spring arm subsequent to the inclined abutment surface on the brake pad. Said stop is used as a tangential abutment for the spring arm. Thus, the action of the spring arm allows the brake pad to be clamped in a rattle-free manner with respect to the brake holder both in radial and tangential directions.

In another favorable embodiment of the brake holder with brake pad guide spring, the first portion of the spring arm, which abuts on the brake pad in the mounted condition, is configured as a slope with respect to the axial direction. In particular, the preloading force of the spring arm is variable in dependence on the axial position of the brake pad at the slope, with the brake pad mounted.

The preloading force of the spring arm with slope thus varies in dependence on the displacement travel of the brake pad in the brake holder. Hence, a force component directed axially to the brake pad results by means of the slope. Said force component can be used for the clearance adjustment between the brake pad and an associated brake disc.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The brake holder1shown in the Figures is a component part of a floating-caliper disc brake frequently used in motor vehicles. Brake holder1is fixed to the vehicle, for example, by way of threaded bores or through-bores2. On the other hand, it is also feasible to integrate the brake holder1into a component fixed to the vehicle such as the steering knuckle. The brake holder1is used for the slidable support of a floating caliper (not shown), on the one hand, and for an axially3slidable accommodation of the brake pads6, on the other hand, said brake pads being arranged on either side of the associated brake disc. In this arrangement, the floating caliper straddles the brake disc and the brake pads6.

To accommodate the brake pads6, the brake holder1comprises holder arms7straddling axially3the radially outwards edge of the brake disc (not shown). In this respect the designations of directions used in the description of the Figures, e.g. axial3, tangential4, and radial5, refer to the axis of rotation of the brake disc. Several guiding surfaces8to10allowing a displaceable guide of the brake pads6are designed at the holder arms7. To this end, lateral guiding portions11of the brake pads6engage, mainly in a form-fit manner, into the guiding recess12in the holder arms7, said recess being formed of the guiding surfaces8to10. Thus, the abutment of the guiding portions11on the guiding surfaces8to10allows transmitting circumferential brake forces that develop into the brake holder1. The design of the L-shaped guiding portions11on the brake pad6and of the associated guiding surfaces8to10further allows a uniform support of the circumferential brake forces on the two holder arms7.

To enhance the ease of motion of the brake pad guide within the holder arms7, there is provision of a brake pad guide spring20, which extends between the brake holder1or the guiding surfaces8to10, respectively, and the brake pad6in a first embodiment according toFIGS. 1 to 2. A brake pad guide spring20of this type prevents the direct contact between brake pad6and brake holder1and facilitates the displaceability of the brake pad6by corresponding surface conditions of the brake pad guide spring20. To this end, the brake pad guide spring20is preferably made of a sheet-metal blank, e.g. of spring steel, or any other material exhibiting good sliding properties at least on its surface. In addition, the brake pad guide spring20has a resilient effect towards the brake pad6so that the brake pad6is retained on the brake holder1in a rattle-free manner.

The brake pad guide spring20comprises a base portion21, which, on both sides thereof, passes over into a guiding portion22, and also comprises a spring arm26. The guiding portion22is provided with contact surfaces23to25for the abutment of the associated brake pad6, said contact surfaces ensuring an easily movable displacement of the brake pad6with respect to the brake holder1. Spring arm26serves for the radial locking engagement of the brake pad6on the brake holder1and additionally brings about rattle-free clamping of the brake pad in relation to the brake holder1. To this end, the brake pad guide spring20is held captive on the holder arm7. This attachment is carried out by means of at least one fixing clamp27,28,29locking the brake pad guide spring20on the brake holder1. According to the first embodiment of the brake pad guide spring20according toFIGS. 1 to 2, the radially5active fixing clamps27,28in each case engage into an undercut13,14on the holder arm7or within the guiding recess12. The fixing clamps27,28themselves are deflected from the guiding portion22by simple machining. Thus, the configuration of the fixing clamps27,28and the associated undercuts13,14allows a particularly favorable mounting of the brake pad guide spring20on the brake holder1. As this occurs, the brake pad guide spring20is shifted radially5into the guiding recess12on the holder arm7until the fixing clamps27,28catch the undercuts13,14. The fixing clamps27,28consequently fix the brake pad guide spring20radially in the holder arm7, and the guiding portion22abuts on the guiding recess12in a clearance-free manner at least in the area of the guiding surfaces8to10. The guiding surfaces8to10or the contact surfaces23to25, respectively, are used for the abutment or support of the brake pads6. The clearance-free abutment of the brake pad guide spring20is achieved, among others, because the angle α enclosed between the contact surfaces23,24at the brake pad guide spring20is dimensioned insignificantly smaller than the angle β enclosed between the guiding surfaces8,9at the holder arm7. Hence, the result is the clearance-free abutment when the brake pad guide spring20is locked. As a whole, the locked fixing clamps27,28provide such a rigid connection that it is impossible to dismount the brake pad guide spring20from the brake holder1without destroying it. The other fixing clamps29embrace the holder arm7axially3on both sides and thereby bring about an axially defined positioning of the brake pad guide spring20on the holder arm7.

For the radially active locking engagement of at least one brake pad6, a spring arm26is additionally designed at the brake pad guide spring20and, by abutting on the brake pad6, simultaneously clamps the brake pad with respect to the brake holder1. According toFIGS. 1 to 2, only one single spring arm26is provided at the brake pad guide spring20, acting only on one of the brake pads6. Of course, designs of the brake pad guide spring20with two arms26that act on both brake pads6are possible as well. More specifically, a first portion16is provided at the spring arm26for the radial locking engagement of the brake pad6, said first portion providing a radial stop16for the brake pad6. Said radial stop16is preferably configured in the form of an angled-off or rounded edge of the spring arm end portion. However, the spring arm26not only causes radial locking engagement of the brake pad6on the brake holder1but also the pad's rattle-free clamping with respect to the brake holder1. To this end, the first portion16of spring arm26bears under spring load against an inclined abutment surface17, on the one hand, and against a tangentially4active stop41on the brake pad6, on the other hand. A spring force component both in radial5and tangential4directions is achieved for the brake pad by the abutment of the spring arm26. Said spring bias ensures a rattle-free arrangement of the brake pad6in radial and tangential directions.

The essentially V-shaped configuration of the spring arm26further brings about an easy mountability of the brake pad6. In this arrangement, the brake pad6is shifted during the brake pad assembly from radially outwards into the brake pad guide spring20locked in the holder arm7until the spring arm26, with its first portion16, will move into abutment on the inclined abutment surface17or on the tangential stop16, respectively. Further, mounting of the brake pad6is additionally simplified by the provision of a mounting ramp18on the spring arm26. Said mounting ramp18facilitates the radial insertion of the brake pad6and prevents it from being jammed.

Another spring force component that acts on the brake pad6is realized by designing a slope19at the first portion16of the spring arm26. Said slope19forms an angle relative to the axial direction3and abuts on the brake pad6when readily mounted. In dependence on the axial position of the brake pad6within the guiding portion22, consequently, there is a variable force effect by means of the spring arm26on the brake pad6. This leads to an axially3directed spring force component tending to urge the brake pad6away from the brake disc (not shown) when the disc brake is ready for work. Thus, the slope19can be used during braking operation for the better adjustment of the clearance between brake pad6and brake disc. As another alternative for realizing an axial spring force component by means of the slope19, the spring arm26can e.g. also be designed asymmetrically with respect to a plane normal to the axial direction3.

FIG. 3a-bshows in two views a brake holder31with an associated brake pad guide spring30in an alternative embodiment. As described already, the brake pad guide spring30includes a base portion33interconnecting two guiding portions32for the brake pad accommodation. In their readily mounted condition, said guiding portions32in turn are arranged in the guiding recesses12of the holder arm34. In contrast to the previously explained embodiment, the brake pad guide spring30according toFIG. 3a-bincludes two spring arms36which abut under bias on an associated brake pad6in each case by way of a first portion35in the form of a radial stop. Thus, both brake pads6can be radially locked and clamped in a rattle-free manner according to this design variant of the brake pad guide spring30. Further, the two spring arms36have a different geometrical shape compared to the first embodiment of the brake pad guide spring. In particular, the spring arms36have a longer and highly curved design. In general, the defined rating of the spring arm36permits adjusting the desired spring bias force that acts on the brake pad6within defined tolerances. Thus, the design of the spring arm allows purposefully adjusting the spring's biasing force depending on the case of application. Different configurations of the spring arm are hence feasible under the invention. Only one single fixing clamp37is provided for the easy-to-mount attachment of the brake pad guide spring30on the brake holder31. Said fixing clamp37has at least one opening38which, with the brake pad guide spring30locked, encloses a correspondingly designed projection39at the holder arm34in a substantially form-fit manner. Due to this arrangement the brake pad guide spring30is fixed on the holder arm34in a radial and axial fashion and, nevertheless, can be mounted radially in a very easy manner.

Another alternative construction of a brake pad guide spring40can be taken from two views referring toFIG. 4a-b. The brake pad guide spring40includes for each of the associated brake pads6a corresponding guiding portion42and a spring arm46. Two fixing clamps47,48embracing the holder arm7are provided to fasten the brake pad guide spring40on the brake holder1or the holder arm7, respectively. More specifically, the fixing clamps47,48abut under preload on the holder arm7in the area of the disc's passage at the holder, that means in a portion of the holder arm7projecting above the brake disc directly radially outside or extending between the guiding recesses12at the holder arm. Thus, the two fixing clamps47,48ensure both radial and axial fixation of the brake pad guide spring40on the holder arm7. Further, the use of fixing clamps47,48of this type obviates the need for an additional machining of the holder arm7for the purpose of attachment of the brake pad guide spring40.

FIGS. 5 to 6show two further variants for the attachment of a brake pad guide spring50,60of the invention on a corresponding holder arm7. Two fixing clamps57,58or67,68, respectively, are provided by means of which the brake pad guide spring50,60is locked at the holder arm7. Thus, the fixing clamps57,58or67,68, respectively, ensure in each case radial and axial fixation of the brake pad guide spring50,60on the holder arm7. According toFIG. 5the fixing clamp57embraces the holder arm7in an arcuate fashion in the area of the disc's passage at the holder so that the fixing clamp57encloses the holder arm7over almost half its periphery. This provides a very good grip of the brake pad guide spring50on the holder arm7, without additional mechanical treatment of the holder arm7.

The variant of the brake pad guide spring60according toFIG. 6achieves the non-detachable attachment on the holder arm7because the fixing clamp67with its end portion is engaged in an associated pocket61of the holder arm7in a generally form-fit manner. This allows also a precise positioning and reliable fixation on the holder arm7.