Disc brake for a motor vehicle

Abstract

Disc brake (1) for a motor vehicle, comprising a guide (30, 130, 230) in which at least one brake pad arrangement (10) is guided so as to be displaceable in a braking-effective manner, wherein the brake pad arrangement (10) has a brake pad carrier (11) to which a vehicle brake pad (13) is attached, which can be brought into interaction with a brake disc to achieve a braking effect, wherein the brake pad carrier (11) has at least one retaining tongue (12), wherein the guide (30, 130, 230) has at least one receiving area (32) and wherein the retaining tongue (12) can be received in the at least one receiving area (32) in a guided manner in an actuating direction (B), wherein a restoring device (30, 130, 230) bears against the at least one retaining tongue (12), via which restoring force acting counter to the actuating direction (B) as a result of an elastic deformation by braking-effective deflection of the brake pad arrangement (10) can be applied thereto, wherein the return device (30,130, 230) has an elastically deformable region (33, 133, 233) for resetting the brake pad carrier (11) and an adjoining plastically deformable region (37, 137, 237) for permanent adaptation to wear of the vehicle brake pad (13), wherein the plastically deformable region (37, 137, 237) is only plastically deformable due to a force acting thereon in the actuation direction (B) along a guide surface (F) of the receiving region (32) when the elastically deformable region (33, 133, 233) has assumed a predetermined, exclusively elastic deformation due to this force, characterized in that the restoring device (130, 230) has a stop (134, 234) which is able to limit the spring travel of the elastically deformable region (133, 233) so that any further displacement of the retaining tongue (12) in the actuating direction (B) leads to a plastic deformation of the plastically deformable area (137,237) leads.,

Description

[0001] The present invention relates to a disc brake for a motor vehicle according to the preamble of claim 1. In particular, the present invention relates to a disc brake comprising a guide in which at least one brake pad assembly is guided so as to be displaceable in a braking-effective manner, wherein the brake pad assembly has a brake pad carrier to which a vehicle brake pad is attached, which can be brought into interaction with a brake disc to achieve a braking effect, wherein the brake pad carrier has at least one retaining tongue, wherein the guide has at least one receiving area and wherein the retaining tongue can be received in the at least one receiving area in a guided manner in an actuating direction, wherein a return device rests on the at least one retaining tongue,via which a restoring force acting counter to the actuation direction can be applied to the brake pad arrangement as a result of elastic deformation by braking-effective deflection of the brake pad arrangement, and wherein the restoring device has an elastically deformable region for restoring the brake pad carrier and an adjoining plastically deformable region for permanent adaptation to wear of the vehicle brake pad.

[0002] Such disc brakes are known from the prior art. For example, the document DE 10 2012 016 737 A1 shows a disc brake which has a return device in the form of a return spring. This return spring has two Fig. 6, which can be elastically deformed during normal operation of the disc brake to reset the brake pad assembly and plastically deformed to compensate for brake pad wear. Consequently, in the aforementioned document, one and the same areas serve both as elastically deformable areas for reset and as plastically deformable areas for wear compensation.

[0003] Such a functional connection between reset and wear compensation is also provided for in document US 8 397 880 B2, which is described in particular in the Fig. 8A and Fig. 8B shows a likewise curved region in the return device shown, which serves as an elastically deformable region for return and also as a plastically deformable region for wear compensation.

[0004] In such systems with elastic and plastic deformation of one and the same area, the return of the brake pads can be impaired, particularly in the case of severe wear that needs to be compensated.

[0005] EP 2 792 899 A1 discloses a disc brake with a member for elastically returning the brake pad towards its inactive position, which member is inserted between the brake pad and the carrier.

[0006] It is therefore an object of the present invention to provide a disc brake in which wear compensation has no effect on the return properties.

[0007] This object is achieved by a disc brake for a motor vehicle having the features of patent claim 1. Nevertheless, in a disc brake of the type initially described, it is provided that the plastically deformable region, due to a force acting thereon in the actuation direction along a guide surface of the receiving region, is only plastically deformable when the elastically deformable region has assumed a predetermined, exclusively elastic deformation due to this force. According to the invention, plastic deformation therefore also occurs when the available extent of elastic deformation has been fully exhausted. This achieves a separation, in particular a spatial separation, of reset and wear compensation.

[0008] A further development of the invention provides that the plastically deformable region is loop-shaped and lies directly against the retaining tongue, and is capable of rolling along the guide surface during plastic deformation. This allows the ongoing plastic deformation available for wear compensation to be progressively inhibited, to such an extent that, at a defined deformation distance along the surface, which corresponds, for example, to the wear limit of the brake pads, no further plastic deformation can occur.

[0009] Preferably, the elastically deformable region extends in a direction different from the plastically deformable region. This allows the installation space required by the reset device within the disc brake to be reduced. Furthermore, the direction of the effective forces of both regions can be selected for better separation of reset and wear compensation.

[0010] In principle, the elastically deformable region can be designed with one or more arms. To individually adjust the spring curve for elastic deformation, the elastically deformable region can have at least two bulges. These can be of the same or different lengths.

[0011] A further development of the invention provides that the return device has a stop designed to limit the spring travel of the elastically deformable region, so that any further displacement of the retaining tongue in the actuation direction leads to a plastic deformation of the plastically deformable region. Such a stop causes a sudden increase in the stiffness of the elastically deformable region, which in turn initiates the plastic deformation of the plastically deformable region to compensate for wear.

[0012] An improvement in the manufacture and / or maintenance of a disc brake according to the invention is achieved, for example, by the reset device having at least two operatively connected elements, one element having only the plastically deformable region. In this way, the elastically deformable region and the plastically deformable region can be manufactured more easily. Furthermore, after wear compensation and replacement of the worn brake pad with a new one, only the element with the plastically deformable region can be replaced.

[0013] Advantageously, the invention provides that the retaining tongue slides along the plastically deformable region for plastic deformation, so that the region is reshaped according to its contact surface with the retaining tongue. Preferably, the contact surface is the lower surface of the retaining tongue, with which the retaining tongue rests on the plastically deformable region. This saves installation space because a synergy occurs between the retaining tongue and the plastically deformable region during its plastic deformation.

[0014] Maximum wear compensation can be precisely determined by having the retaining tongue engage directly at the end section of the plastically deformable area, which limits the displacement of the retaining tongue in the actuation direction after complete plastic deformation through positive engagement with the retaining tongue. In this state, the brake pads can be prevented from experiencing excessive wear, which could lead to inadequate performance or even unwanted slipping of the pads into the gap between the brake disc and the brake carrier.

[0015] In particular, according to the invention, the return device can be a guide formed from sheet metal, which has a projecting, elastically deformable, loop-shaped region and an adjoining plastically deformable region extending into the guide, with recesses in the sheet metal defining the elastic and plastic deformability. In this way, a compact design is achieved while utilizing the available space for guiding the retaining tongue.

[0016] The invention further relates to a brake pad assembly for a disc brake according to one of the preceding claims, wherein the brake pad assembly has a brake pad carrier to which a vehicle brake pad is attached, which can be brought into interaction with a brake disc to achieve a braking effect, wherein the brake pad carrier has at least one retaining tongue and wherein the guide has at least one guide section, wherein the retaining tongue can be received in the at least one guide section in a guided manner in an actuation direction, wherein a restoring device is attached to the at least one retaining tongue, via which a restoring force acting counter to the actuation direction can be applied to the brake pad assembly as a result of an elastic deformation by means of a braking-effective deflection of the brake pad assembly,wherein the return device has an elastically deformable region for returning the brake pad carrier and an adjoining plastically deformable region for permanent adaptation to wear of the vehicle brake pad, and wherein the plastically deformable region is only plastically deformable due to a force acting thereon in the actuation direction along a guide surface of the receiving region when the elastically deformable region has assumed a predetermined, exclusively elastic deformation due to this force.

[0017] Preferably, two return devices acting in opposite directions share a common, one-piece base body. This makes assembly and disassembly during production and maintenance faster and easier. Such a base body can preferably be U-shaped and connect the return devices to one another by means of a connecting bracket, which simultaneously serves as the attachment to the brake carrier. Preferably, additional attachment extensions are provided, each of which is directed symmetrically inward into the U-shaped base body and is suitable for attachment to the brake carrier.

[0018] The invention is explained below by way of example with reference to the accompanying figures. They show: Fig. 1 a spatial representation of a disc brake according to the invention; Fig. 2 a spatial representation of the brake carrier of the disc brake according to the invention from Fig. 1 with mounted reset devices; Fig. 3 a spatial representation of the brake pad carrier of the disc brake according to the invention from Fig. 1 with retaining tabs; Fig. 4, Fig. 5 spatial representations of a Fig. 2 shown first reset device according to a first embodiment; Fig. 6 a side view of the first reset device from Fig. 4, Fig. 5; Fig. 7 a cross-section through the Fig. 1 disc brake shown at the level of the reset device; Fig. 8 an enlargement of the Fig. 7 shown cross-section; Fig. 9-11 spatial representations of the first return device with the retaining tongue resting on the plastically deformable area in three states of plastic deformation: where Fig. 9 none, Fig. 10 a medium and Fig. 11 show maximum plastic deformation; Fig. 12, Fig. 13 Cross sections of a second return device with stop according to a second embodiment of the invention and in two states of elastic deformation: where Fig. 12 none and Fig. 13 show a maximum (at the stop) elastic deformation; Fig. 14 a side view of the second reset device from Fig. 12, Fig. 13; Fig. 15-17 spatial representations of the second return device with the retaining tongue resting on the plastically deformable area in three states of plastic deformation: where Fig. 15 none, Fig. 16 a medium and Fig. 17 show maximum plastic deformation; Fig. 18 a spatial representation of a third reset device according to a third embodiment with a two-part structure; Fig. 19 an enlargement of the Fig. 18 shown connection point of the two-part structure of the third reset device; Fig. 20 a cross-section through the Fig. 18, Fig. 19 shows the third reset device; Fig. 21 a side view of the third reset device from Fig. 18-20; Fig. 22, Fig. 23 mounting-specific versions of the reset device; and Fig. 24, Fig. 25 two integrally formed return devices.

[0019] The following three embodiments differ essentially with regard to the design of their reset devices (30, 130, 230). Example 1

[0020] In the Fig. 1 shows a disc brake 1 according to the invention for a motor vehicle. Two opposing brake pad assemblies 10 can be seen, which are constructed from a brake pad carrier 11 with lateral retaining tabs 12 and a vehicle brake pad 13. The brake pad assemblies 10 face each other on their vehicle brake pad side and are spaced apart from each other such that a brake disc (not shown) can be arranged between them and the vehicle brake pad 13 can be brought into interaction with the brake disc to achieve a braking effect by moving the brake pad assemblies 10 in an actuation direction B. This movement in the actuation direction B can be effected in a known manner via a hydraulic actuation mechanism, wherein the brake pad assemblies 10 are held by a brake carrier 20 and are guided in a braking-effective manner by means of the retaining tabs 12.

[0021] In Fig. 2, the brake pad assemblies 10 are removed from the disc brake 1. Return devices 30 formed from sheet metal are attached to the brake carrier 20 as a guide.

[0022] Fig. 3 shows only the brake pad arrangements 10 from Fig. 1 with the return devices 30, which in the illustration surround the retaining tongues 12 of the brake pad carriers 11.

[0023] The Fig. 4 and Fig. 5 show two spatial representations of the reset device 30. These are designed as sheet metal parts with a base body 31 and have a U-shaped receiving area 32 in which the retaining tongue 12 can be received in a guided manner in and against the actuation direction B. The reset device 30 rests against the retaining tongue 12, via which a restoring force acting counter to the actuation direction B can be applied to the brake pad arrangement 10 as a result of an elastic deformation due to braking-effective deflection of the latter.

[0024] The reset device 30 has a loop-shaped, elastically deformable region 33 projecting from the base body 31 for reset of the brake pad carrier 10, as well as a loop-shaped, plastically deformable region 37 adjoining it via a transition region 35 for permanent, automatic compensation of wear of the vehicle brake pad 13. It can be seen that the elastically deformable region 33 extends in a direction different from the plastically deformable region 37. The plastically deformable region 37 projects into the area of ​​the guide 32 of the reset device 30. The properties for elastic and plastic deformability of the respective regions 33, 37 are defined by recesses or cutouts in the material.At the end of the plastically deformable region 37, an engagement lip 39, which is essentially non-deformable during operation, adjoins as an end section 39, which serves as a force introduction point for the retaining tongue 12 moved in the actuation direction B. Furthermore, a surface of the base body 31 is referred to as a guide surface F, along which the transition region 35 extends parallel, wherein the plastically deformable region 37 is capable of rolling along the guide surface F during plastic deformation.

[0025] Fig. 6 shows a view from the left, ie in the direction of actuation B, into the Fig. 4 and Fig. 5, the side of the return device 30 is shown. It can then be seen that the elastically deformable region 33 has two arms of different lengths, which are also curved into the interior of the disc brake 1 to save space.

[0026] Fig. 7 and Fig. 8 show a respective cross section through the return device 30 and the retaining tongue 12 brought into contact with the stop lip 39. In the Fig. In the state shown in Figure 8, no elastic or plastic deformation has occurred. This state defines a specific guide distance A o in the rest position, which is measured parallel to the guide surface F from the left edge of the guide surface F, which faces the elastically deformable region 33, to the point of engagement of the retaining tongue 12 on the engagement lip 39.

[0027] The Fig. 9 to 11 show the course of the plastic deformation of the plastically deformable area 37 for wear compensation.

[0028] In the Fig. 9, no plastic deformation of the plastically deformable area 37 has yet taken place, because the guide distance A 1merely indicates that the maximum elastic deformation of the elastically deformable region 33 has been reached and any further movement of the retaining tongue 12 in the direction of movement B will lead to a permanent deformation of the plastically deformable region 37. In other words, the plastically deformable region 37 is only plastically deformable due to a force acting on it in the actuation direction B along a guide surface F of the receiving region 32 when the elastically deformable region 33 has assumed a predetermined, exclusively elastic deformation due to this force and further movement of the brake pad is still possible during a braking-effective displacement. This only occurs when the vehicle brake pad 13 in question is already worn to such an extent that movement of the retaining tongue 12 in the actuation direction B over a longer distance is possible than in the case of regular service braking.This “distance difference” between a new and a worn vehicle brake pad 13 is thus permanently compensated or compensated for by the plastic deformation and the associated displacement of the contact point of the retaining tongue 12 with the engagement lip 39.

[0029] In Fig. 10 shows that the plastic deformation occurs when the retaining tongue 12 slides along the plastically deformable region 37 for the plastic deformation thereof, whereby the region 37 is reshaped by the interaction of its contact surface with the retaining tongue 12. As a result, the guide distance A 2 compared to A 1 The wear compensation or the already mentioned “distance” can be calculated with A 2 - A 1 calculate.

[0030] The Fig. 11 shows the maximum possible compensation, in which the plastically deformable region 37 is virtually completely rolled out along the guide surface F. After the complete plastic deformation, the end section 39 limits further displacement of the retaining tongue 12 in the actuation direction B by positive engagement with the retaining tongue 12. Example 2

[0031] The second embodiment according to the Fig. 12 to 17 differs from the first embodiment in that the return device 130 has a stop 134 which is able to limit the spring travel X of the elastically deformable region 133, so that any further displacement of the retaining tongue 12 in the actuating direction B leads to a plastic deformation of the plastically deformable region 137.

[0032] In this context, the Fig. 12 and Fig. 13 the two states of the elastically deformable region 133.

[0033] In Fig. 12, no elastic deformation has yet occurred, which is why the entire spring travel X (>0) is available, which is measured from the inner surface of the stop 134, facing to the right in the figure, to the opposite stop point. The guide distance in this rest position, which is measured parallel to the guide surface F from the left edge of the guide surface F, which faces the elastically deformable area 133, to the point of application on the engagement lip 139, is designated A 0 designated.

[0034] In Fig. 13, this spring travel X has already been used up due to the actuation of the brake system assembly 10 and the associated retaining tongue 12 in the actuation direction B (X=0). The stop 134 rests against the opposite stop surface. Consequently, the guide distance in this state is A 1 designated.

[0035] Fig. 15 to 17 show as well as the Fig. 9 to 11 of the first embodiment, the plastic deformation of the plastically deformable area 139, starting from a guide distance A1 in Fig. 15 the maximum plastic deformability in Fig. 17 is reached at a guide distance of A3. Example 3

[0036] The third embodiment according to one of the Fig. 18 to 21 differs from the second embodiment in that the return device 230 has, in addition to a stop 234, two separately formed elements M1, M2 which, however, in the state shown, are operatively connected to one another, wherein the one element M1 has only the plastically deformable region 237.

[0037] The Fig. 18 shown and in Fig. The reset device 230 shown in Figure 19 as an enlarged view reveals a transition region between the elements M1 and M2, wherein the element M1 is hooked into the elastically deformable region 233 of the element M2 by means of a hook and rests on the latter in the actuation direction B, so that both during actuation and during resetting of the brake pad arrangement 10, a compressive stress and no tensile stress, for example on the hook, prevails. While this embodiment provides a detachable connection between the elements M1 and M2, a permanent connection, e.g., by gluing, soldering, or welding, can also be provided.

[0038] The Fig. 20 and Fig. 21 correspond to the Fig. 12 and Fig. 14 of the second embodiment known representations of the reset device 230, wherein the special feature of the two-part construction of the elements M1 and M2 can be seen.

[0039] The Fig. 22 and Fig. 23 show two return devices 130a and 130b according to the second embodiment, wherein the base body 131a and 131b is adapted accordingly for attachment to the brake carrier 20. Thus, in the Fig. 22 fixing projections 141 are provided, which, in cooperation with at least one locking claw 142, ensure this fastening. For the same purpose, Fig. 23 two lateral locking claws 143 are provided, which also engage directly on the brake carrier 20.

[0040] The Fig. 24 and Fig. 25 show return devices 130c acting in opposite directions, whose base bodies 131c are connected in a U-shape in one piece via a connecting bracket 145. Attachment extensions 147 are provided, each of which is directed symmetrically inwards into the U-shaped base body 131c and is suitable for attachment to the brake carrier 20. In this way, for example, the Fig. 2 can be replaced by a single element, which is advantageous during assembly and disassembly in production and maintenance. Such a one-piece base body can be provided for all embodiments of the reset devices described here.

Claims

[1] Disc brake (1) for a motor vehicle, comprising a guide (30, 130, 230) in which at least one brake pad arrangement (10) is guided so as to be displaceable in a braking-effective manner, wherein the brake pad arrangement (10) has a brake pad carrier (11) to which a vehicle brake pad (13) is attached, which can be brought into interaction with a brake disc to achieve a braking effect, wherein the brake pad carrier (11) has at least one retaining tongue (12), wherein the guide (30, 130, 230) has at least one receiving area (32) and wherein the retaining tongue (12) can be received in the at least one receiving area (32) in a guided manner in an actuating direction (B), wherein a restoring device (30, 130, 230) bears on the at least one retaining tongue (12), via which restoring force acting counter to the actuating direction (B) is generated as a result of an elastic Deformation can be applied to the brake pad arrangement (10) by braking-effective deflection,wherein the return device (30, 130, 230) has an elastically deformable region (33, 133, 233) for returning the brake pad carrier (11) and an adjoining plastically deformable region (37, 137, 237) for permanent adaptation to wear of the vehicle brake pad (13), wherein the plastically deformable region (37, 137, 237) is only plastically deformable due to a force acting thereon in the actuation direction (B) along a guide surface (F) of the receiving region (32) when the elastically deformable region (33, 133, 233) has assumed a predetermined, exclusively elastic deformation due to this force, characterized bythat the return device (130, 230) has a stop (134, 234) which is able to limit the spring travel of the elastically deformable region (133, 233), so that any further displacement of the retaining tongue (12) in the actuating direction (B) leads to a plastic deformation of the plastically deformable region (137, 237). [2] Disc brake (1) according to claim 1, characterized by that the plastically deformable region (37, 137, 237) is loop-shaped and lies directly against the retaining tongue (12) and is capable of rolling along the guide surface (F) during plastic deformation. [3] Disc brake (1) according to claim 1 or 2, characterized by that the elastically deformable region (33, 133, 233) extends in a direction different from the plastically deformable region (37, 137, 237). [4] Disc brake (1) according to one of the preceding claims, characterized bythat the elastically deformable region (33, 133, 233) has at least two bulges. [5] Disc brake (1) according to one of the preceding claims, characterized by that the restoring device (230) has at least two elements (M1, M2) which are operatively connected to one another, wherein one element (M1) has only the plastically deformable region (237). [6] Disc brake (1) according to one of the preceding claims, characterized by that the retaining tongue (12) slides along the plastically deformable region (37, 137, 237) for the plastic deformation thereof, so that the region (37, 137, 237) is reshaped in accordance with its contact surface with the retaining tongue (12). [7] Disc brake (1) according to one of the preceding claims, characterized bythat the return device (30, 130, 230) represents a guide formed from sheet metal, which has a projecting, elastically deformable and loop-shaped region (33, 133, 233) and an adjoining plastically deformable region (37, 137, 237) projecting into the guide, wherein recesses in the sheet metal define the elastic and plastic deformability.

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