DE102013016779A1 - Disc brake and brake pad assembly with a reset device - Google Patents

Abstract

The invention relates to a disc brake (10), in particular for a motor vehicle, comprising a carrier (12), a brake lining arrangement (14) comprising a friction lining guided in the carrier (12) with a pad back plate (16) and a return device (18) , The pad back plate has a first recess (20) and the friction pad is engageable with a brake disc to achieve a braking effect. The return device comprises at least one return spring (22) supported by the carrier and is adapted to apply a restoring force to the pad back plate to return the friction pad to a home position after deflection. The brake pad assembly includes at least one coupling member (24) extending substantially perpendicular to a surface of the pad backplate through the first recess and engaging radially bias therebetween such that biasing of the coupling member is provided between the coupling member and the inner peripheral surface of the first recess friction force acting against the inner circumferential surface acts. The coupling member is configured to couple the return device to the pad back plate and slide along its longitudinal direction in the first recess when the resistance of the return device to the deflecting movement exceeds the frictional force such that the pad back plate is displaceable relative to the wear compensating coupling member.

Description

The invention relates to a disc brake, in particular for a motor vehicle, comprising a carrier, a brake pad assembly comprising a friction lining guided in the carrier with a pad back plate and a return device, wherein the pad back plate has a first recess and wherein the friction pad with a brake disc for achieving a Wherein the return device comprises at least one return spring supported by the carrier, and wherein the return device is adapted to exert a restoring force on the pad back plate to return the friction pad to a home position after deflection.

Such a disc brake is for example off DE 34 34 421 A1 known. The partially coated disc brake described therein has a brake carrier on which both sides of a brake disc are formed parallel to this boundary surfaces facing away from each other. At right angles to the boundary surfaces of the brake carrier on both sides of the brake disc each have a pair of mutually facing parallel guide surfaces, between each of which a brake shoe is arranged, each having a back plate made of steel. Approximately in the middle of each side surface of the back plate, a laterally open recess is dotted with a dovetailed profile in which a guide body made of sheet steel is inserted parallel to an axis of the brake disc. On a side facing away from a braking surface of the brake shoe end of a base of a U-shaped profile of the guide body from the same piece of sheet metal, a spring arm is formed, which is bent outwards by about 100 degrees and rests with its outer edge on the associated boundary surface. The spring arm returns a spring travel when it is deformed from its rest position into an end position in which it extends at right angles to the base and as a result bears against the associated boundary surface of the brake carrier over the entire surface.

In general, the pad back plate is deflected at the beginning of a braking process from its initial position in the direction of the brake disc until one of the brake disc facing surface of the friction pad contacts the brake disc. If the motor vehicle is in motion at this time, this results in a sliding friction between the friction lining and the brake disc, whereby the friction lining is worn. After the end of the braking process, the pad back plate is returned to its original position, in which the friction lining is spaced from the brake disc. However, due to the wear occurring over time when braking, the distance (so-called clearance) between the surface of the friction lining and the brake disk is greater than it originally was. Consequently, a brake lever or pedal must be further deflected from its initial position in a subsequent braking operation in order to achieve a braking effect.

The driver of the vehicle is imparted an imprecise and indirect brake feel because of the resulting increasing pedal travel. In addition, extended by a large clearance the time between the initiation of the braking process and the actual occurrence of a braking effect. Thus, a large clearance affects negatively on the safety of the motor vehicle.

To keep the clearance constant, d. H. Independently of the wear of the friction lining, disc brakes known from the prior art have wear compensation devices. However, these are sometimes designed relatively expensive.

It is an object of the present invention to provide a disc brake of the type described, which gives a driver a direct brake feel, provides a good wear compensation and yet is easy and inexpensive to produce.

This object is achieved by a disc brake of the type described, in which it is provided that the brake pad assembly comprises at least one coupling part which extends substantially perpendicular to a surface of the pad back plate through the first recess and is engaged with this under radial bias, such that between the coupling part and the inner peripheral surface of the first recess, a frictional force caused by bias of the coupling part against the inner peripheral surface acts. The coupling part is preferably formed as a separate component and is adapted to couple the return device to the pad back plate and slide along its longitudinal direction in the first recess when the resistance of the return device against the deflecting movement (restoring force) exceeds the frictional force. As a result, the pad back plate is displaceable relative to the coupling part for wear compensation.

The restoring force is inventively exerted by the return spring, which is preferably designed so that the restoring force increases as little as possible in proportion to the deflection from the starting position in a defined working range. Alternatively, however, the restoring force can also rise disproportionately or at a lower rate than the deflection. In other words, the spring rate ("spring rate") is preferred regardless of the deflection as low as possible. However, it can also increase with the deflection (progressive spring behavior) or fall with the deflection (degressive spring behavior). The return spring may be formed, for example, as a leaf spring.

The working range of the return spring is according to the invention defined by a first stop on which the return spring in un-actuated brake, and a second stop on the carrier, which increases by striking the return spring to the second stop their resistance to further deflection abruptly. This abruptly increased resistance (corresponding to a sudden extreme stiffening of the return spring) then immediately exceeds the effective frictional force between the coupling part and the pad back plate and leads to a shift of the pad back plate relative to the coupling part for wear compensation. In other words, the spring arm preferably moves freely in a working area which is defined by the first and the second stop, wherein it acts by means of the coupling part on the pad back plate with as constant a restoring force. As the spring arm reaches and contacts the second stop, the resistance of the return spring (spring rate) increases abruptly to exceed the frictional force between the coupling portion and the pad back plate. As a result, an easily adjustable Betätigungswegabhängigkeit is produced, which allows a tolerance-independent adjustability with respect to the beginning and the size of the wear compensation. A corrosion-related setting of the pad back plate, z. B. in the first recess, can be solved. At the same time, such a return device is inexpensive to produce.

According to the invention, the first recess may be substantially spaced from a lateral edge of the pad back plate. Essentially here means that at least 30 to 50 percent, preferably at least 50 percent, of their cross-sectional area are spaced from the lateral edge. As a lateral edge here the edge of the pad back plate is referred to, which runs substantially perpendicular to an interface between the pad back plate and the friction lining. For example, the 50 percent of the cross-sectional area may be further spaced from the lateral edge than 1-10 mm, preferably about 5 mm. Alternatively, the first recess may be completely spaced from the lateral edge. It is then formed completely closed along its inner circumferential surface within the pad back plate. This has the advantage that at the lateral edge of the pad back plate more space for other facilities, such as a (separate) Geräuschdämpfungs- and / or spring element or a pad back plate guide exists.

The first recess preferably has a circular cross-section. If this is the case, it may for example be made by a simple core hole. It may alternatively have a polygonal, in particular triangular or quadrangular, for example rectangular, or an elliptical cross-section. The first recess passes through the pad back plate at least partially, preferably completely. The coupling part preferably has the same cross-sectional shape / cross-section as the first recess.

The frictional force is preferably adjusted via the bias of the coupling part in the first recess. The bias causes a directed against a direction of a surface normal to the inner peripheral surface, d. H. with respect to a longitudinal direction of the coupling part radially outwardly directed, contact force. The friction force is thus dependent on the contact pressure. A static friction force, ie the maximum force that can be exerted by the return spring, without the pad back plate slides relative to the coupling part, and / or a sliding friction, ie the force that counteracts the restoring force during sliding, for example, based on material properties, for Example based on an elasticity of the coupling part, easily predeterminable.

Advantageously, the driver is thus taught even after many and / or intense braking, for example, after several full brakes starting from high speeds, a direct and precise brake feel. Nevertheless, the friction lining is sufficiently spaced after braking against the brake disc, creating a clearance between the friction lining and the brake disc is formed. Since then there is no contact between the friction lining and the brake disc, no residual grinding moments between the brake disc and the friction lining act. Such undesirable residual grinding torques usually caused an increased fuel consumption and a noticeable noise emission.

In one embodiment of the invention, the return device on a locking clip with two legs. The locking clip preferably extends parallel to the longitudinal direction of the coupling part and it surrounds the carrier at least in sections. The restoring device can be formed on the carrier and / or fixed on the carrier via the locking clip. The restoring device is arranged at least in sections between the carrier and the pad back plate.

In one development of the invention, the return device on a support bracket which engages around the carrier at least partially laterally. This support bracket preferably extends perpendicular to the coupling part. It may, for example, have an omega shape.

According to the invention, it can further be provided that the return device has a hook-shaped section on which the first stop is arranged. The hook-shaped portion preferably extends away from the pad back plate. An end portion of the return spring may be supported on the hook-shaped portion of the return device when the return spring is in its initial position. In this initial position, the return spring may for example be biased. The return spring may have a spring arm, on which the end portion is formed. The end portion of the return spring may have an impression with a preferably U- or omega-shaped cross section which extends over the entire width of the return spring.

In a development of the invention, the return device has an additional stop area. An additional indentation formed on a side of the spring arm opposite the end section with respect to the position of the coupling part is then configured to strike against this additional stop area. Thus, the effect of the second stop can be increased, or the load acting on the impression in the region of the end section can be reduced.

In order to simplify the production of the invention, the return device may be formed, for example, in one piece of material. In this case, the return device is preferably made of a single piece of sheet metal, such as steel spring plate or aluminum sheet, by bending or pressing. The first recess may be formed in the region of an extension of the pad back plate. Thus, the friction lining can be arranged on the rest of the pad back plate. Alternatively, the return device may also be made of a wire spring.

In a further embodiment of the invention, the return spring may have a second recess. If so, the coupling member may be configured, for example, to engage the second recess. In this case, the coupling part preferably protrudes through the second recess. Alternatively, however, it may only partially protrude into the second recess. The coupling part may extend substantially perpendicular to the second recess. It may in particular be fitted in the first and / or in the second recess by interference fit.

According to the invention, it may further be provided that the coupling part is sleeve-shaped and / or cylindrical. The coupling part may for example be made of a spring steel. Such a sleeve-shaped cylindrical coupling part is particularly simple and quick to produce, for example by bending and optionally subsequent rolling around a mandrel. This is particularly advantageous if the coupling part is designed as a separate component. Regardless of whether the coupling member is sleeve-shaped and / or cylindrical, it has a longitudinal direction along which it is arranged to frictionally seat in the first recess under radial bias and to slide when the frictional force is exceeded. The coupling part preferably has at least one slot extending along the longitudinal direction. Such a slot has the advantage that the production of the coupling part is simplified and that the coupling part can be guided by the slot.

In addition, according to the invention, the coupling part can have at least one end stop, which is set up to limit a distance over which the coupling part can be inserted in the second recess. The coupling part is preferably made in one piece of material from a metal sheet. The end stop may be formed, for example, in the form of two latch straps which extend obliquely from a surface of the coupling part on mutually opposite sides of the coupling part at a shallow angle. For example, they can be outwardly, d. H. in the radial direction, or inwards, d. H. in antiradial direction, extend. These latch straps serve to secure the coupling part from slipping through the second recess. At the same time they serve the return spring against opening, d. H. against overcoming the first stop, secure. Such a configured coupling part has the advantage that it can be easily connected by insertion into the second recess with the return device.

In a further embodiment of the invention, the return spring and / or the pad back plate each have a guide extension, which projects into the first and / or in the second recess and which is in engagement with the slot of the coupling part, so that the coupling part against rotation is secured in the first and second recess.

The invention further relates to a brake pad assembly for a disc brake of As previously explained in detail, it is provided in this disc brake that the brake pad assembly comprises at least one coupling part which extends substantially perpendicular to a surface of the pad back plate through the first recess and is engaged with this under radial bias. The coupling member is engaged with the first recess under radial bias so that a frictional force caused by bias of the coupling member against the inner peripheral surface acts between the coupling member and the inner circumferential surface of the first recess. The coupling member is adapted to couple the return device to the pad back plate and to slide along its longitudinal direction in the first recess when the resistance of the return device exceeds the friction force such that the pad back plate is displaceable relative to the wear compensating coupling member.

The invention is explained below by way of example with reference to the accompanying figures. They show:

1 a partial perspective view of a disc brake according to the invention in a rear view looking towards a support;

2 a partial view of the disc brake 1 in a side view looking towards a back of a pad back plate;

3 a partial view of the disc brake 1 in a side view looking along a longitudinal side of the pad back plate;

4 a detailed view of a return device of in 1 shown disc brake in a side view with a view along a longitudinal side of the pad back plate;

5 a detailed view of a return device of in 1 shown disc brake in a side view looking in the opposite direction 4 ;

6 a front perspective view of the disc brake 1 ;

7 a cross-sectional view of a spring arm of in 1 shown disc brake; and

8th a detailed perspective view of a restoring device according to the invention according to a further embodiment, wherein a portion of a spring arm and a portion of a coupling part are shown.

In 1 is a partial perspective view of a disc brake according to the invention 10 shown. The disc brake 10 includes a carrier 12 and a brake pad assembly 14 one in the carrier 12 guided friction lining (not shown) with a pad back plate 16 and a return device 18 includes. The pad back plate 16 has a first recess 20 and the friction pad is engageable with a brake disc (not shown) to achieve a braking effect.

In addition, the reset device includes 18 a return spring 22 with a spring arm 46 , The return spring 22 is from the carrier 12 supported. The reset device 18 is adapted to a restoring force F on the pad back plate 16 exercise to move the friction lining after a deflection to a starting position. The brake pad assembly 14 comprises a coupling part 24 which is substantially perpendicular to a surface 26 the pad back plate 16 through the first recess 20 extends and is engaged with this under radial bias, so that between the coupling part 24 and the inner peripheral surface of the first recess 20 one by bias of the coupling part 24 friction force acting against the inner circumferential surface acts.

The coupling part shown here 24 is manufactured in one piece from a spring steel sheet. It is set to the reset device 18 with the pad back plate 16 and it is also set up along its longitudinal direction in the first recess 20 to slide when the resistance of the return device against the deflecting movement F exceeds the friction force, so that the pad back plate 16 relative to the coupling part 24 is displaceable for wear compensation. The coupling part also has an end stop in the form of two latch straps 23 . 25 on, based on mutually opposite sides of the coupling part 24 at a shallow angle obliquely from a surface 21 of the coupling part to the outside, ie in the radial direction of the coupling part, extend.

As in the 1 and 2 shown, the return device 18 a locking clip 28 with two thighs 30 . 32 on. The locking clip 28 extends parallel to the longitudinal direction of the coupling part 24 and she embraces the wearer 12 at one on the carrier 12 trained lead 31 , The thigh 30 is on a side facing away from the coupling part of the projection and the legs 32 is arranged on a coupling part facing side of the projection. The reset device 18 is on the carrier 12 molded and over the locking clip 28 to the carrier 12 fixed.

The 3 to 5 show a part of the disc brake 10 in a page total view and in two side detail views from opposite directions. The reset device 18 has a hook-shaped section 42 up, extending from the pad back plate 16 as an extension of the thigh 30 extends away. An end section 44 the return spring 22 rests on the hook-shaped section 42 the return device 18 in the area of a first stop 34 when the return spring 22 in their starting position, in which they are in the 1 to 6 is shown is located. In this initial position, it is biased so that the pad back plate 16 has no game. The return spring 22 is open, ie the end section 44 is not with the first stop 34 connected, but only based on it. At the end section 44 is also an imprint 35 educated. When the return spring 22 to a sufficient extent, that is deflected around its work area by a brake actuation from the starting position, it contacts one on the carrier 12 trained second stop 36 , which increases the resistance of the reset device 18 increased abruptly against another deflection. The further deflection of the pad back plate thus has the consequence that the coupling part slides through the first recess for wear compensation.

Such a return device has a long lever arm for the return (see figures). It is therefore precise and robust and at the same time easy to produce. Furthermore, the return device also comes without a stop section formed on it, because the carrier itself serves as a stop. By defining a working area between the first and second stops, it is also ensured that the return spring is not plastically deformed during assembly, for example.

The shown return device 18 has an additional stop section 37 on, with respect to the position of the coupling part 34 to the end section 44 opposite side of the spring arm 46 is arranged and can correspond to an additional (not shown) impression of the spring arm, in order to those in the embossing 35 to reduce acting load. The reset device 18 is formed material integral. Your return spring 22 has a second recess 60 on, with which the coupling part 24 engaged. The coupling part 24 protrudes through the second recess 60 therethrough.

In 6 is the disc brake 10 shown in a perspective front view. The coupling part 24 passes through the pad back plate 16 Completely. It is also shown how the return device 18 on the carrier 12 is formed. In particular, it follows one of the pad back plate 16 facing, in 6 through the return device 18 hidden side surface 62 of the carrier. The reset device 18 has a guide rail 64 on, which is parallel to the coupling part 24 extends and at a bottom 66 the pad back plate 16 between the pad back plate 16 and the carrier 12 is arranged. As in 6 it can be seen, is the first recess 20 in the area of an extension 68 the pad back plate 16 educated. In 6 is further shown that the return device 18 a support bracket 38 which has the carrier 12 partially engages laterally. The support bracket 38 extends perpendicular to the coupling part 24 , It has an omega shape (cf. 1 to 5 ).

The cross-sectional view off 7 shows in detail that the coupling part 24 sleeve-shaped and cylindrical and a slot 40 extending in the longitudinal direction of the coupling part 24 extends (cf. 1 and 6 ). The coupling part 24 is in the first and / or the second recess 20 . 60 fitted by interference fit. The return spring 22 has a leadership extension 70 on that in the second recess 60 protrudes into and with the slot 40 of the coupling part 24 engaged so that the coupling part 24 against rotating in the second recess 60 is secured.

A section of a return spring 80 and a portion of a coupling part 82 an alternative embodiment of a disc brake according to the invention are in 8th shown. The return spring 80 differs from the return spring 22 in that a spring arm 84 the return spring 80 no recess 60 (and therefore no leadership extension 70 ) having. In addition, the return spring has 80 all features of the return spring 22 on. The coupling part 82 differs from the coupling part 24 in that instead of the latch straps 23 . 25 ratchet straps 86 . 88 having. These latch straps 86 . 88 are directed inward rather than outward. The coupling part 82 also has a third recess 90 on, which is adapted to the spring arm 84 at least partially record in it. When the spring arm 84 in the recess 90 is recorded, the latch tabs snap 86 . 88 a, so that the spring arm fixed to the coupling part 82 connected is.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 3434421 A1 [0002]

Claims (15)

Disc brake ( 10 ), in particular for a motor vehicle, having - a carrier ( 12 ), - a brake pad assembly ( 14 ), one in the carrier ( 12 ) guided friction lining with a pad back plate ( 16 ) and a reset device ( 18 ), wherein the pad back plate ( 16 ) a first recess ( 20 ) and wherein the friction lining is engageable with a brake disc for achieving a braking effect, and wherein the return device ( 18 ) at least one return spring ( 22 . 80 ) received from the carrier ( 12 ) and wherein the return device ( 18 ) is adapted to a restoring force on the pad back plate ( 16 ) in order to move the friction lining back to a starting position after a deflection, characterized in that the brake lining arrangement ( 14 ) at least one coupling part ( 24 . 82 ), which is substantially perpendicular to a surface of the pad back plate (FIG. 16 ) through the first recess ( 20 ) and is engaged with this under radial bias, so that between the coupling part ( 24 . 82 ) and the inner peripheral surface of the first recess ( 20 ) one by bias of the coupling part ( 24 . 82 ) acting against the inner peripheral surface friction force acts, wherein the coupling part ( 24 . 82 ) is adapted to the reset device ( 18 ) with the pad back plate ( 16 ), and wherein the coupling part ( 24 . 82 ) is arranged, along its longitudinal direction in the first recess ( 20 ) to slide when the resistance of the return device against the deflecting movement exceeds the friction force, so that the pad back plate ( 16 ) relative to the coupling part ( 24 . 82 ) is displaceable for wear compensation. Disc brake ( 10 ) according to claim 1, characterized in that the return device is a locking clip ( 28 ) with two legs ( 30 . 32 ), wherein the locking clip ( 28 ) parallel to the longitudinal direction of the coupling part ( 24 . 82 ) and the carrier ( 12 ) at least partially encompasses, wherein the return device ( 18 ) on the carrier ( 12 ) and via the locking clip ( 28 ) to the carrier ( 12 ) is fixed. Disc brake ( 10 ) according to claim 1 or 2, characterized in that the return device ( 18 ) a support bracket ( 38 ) comprising the carrier ( 12 ) at least partially laterally engages around and perpendicular to the coupling part ( 24 . 82 ), wherein the support bracket ( 38 ) has an omega shape. Disc brake ( 10 ) according to one of the preceding claims, characterized in that the return device ( 18 ) a hook-shaped section ( 42 ) extending from the pad back plate ( 16 ) and on which a first stop ( 34 ), wherein an end portion ( 44 ) of the return spring ( 22 . 80 ) on the hook-shaped portion ( 42 ) of the return device ( 18 ) in the area of the first stop ( 34 ) is supported when the return spring ( 22 . 80 ) is in its initial position in which it is biased. Disc brake ( 10 ) according to claim 4, characterized in that the carrier ( 12 ) a second stop ( 36 ), wherein a resistance of the return spring ( 22 . 80 ) against a further deflection from the second stop ( 36 ) is suddenly increased. Disc brake ( 10 ) according to one of the preceding claims, characterized in that the return device ( 18 ) is formed in one piece material. Disc brake ( 10 ) according to one of the preceding claims, characterized in that the first recess ( 20 ) in the region of an extension of the pad back plate ( 16 ) is trained. Disc brake ( 10 ) according to one of the preceding claims, characterized in that the return spring ( 22 ) has a second recess, and the coupling part ( 24 . 82 ) is adapted to be engaged with the second recess, the coupling part ( 24 . 82 ) protrudes through the second recess. Disc brake ( 10 ) according to one of the preceding claims, characterized in that the coupling part ( 24 . 82 ) is sleeve-shaped and / or cylindrical and at least partially a slot ( 40 ) which extends in the longitudinal direction of the coupling part ( 24 . 82 ). Disc brake ( 10 ) according to one of the preceding claims, characterized in that the coupling part ( 24 . 82 ) made of a spring steel and is cylindrical and sleeve-shaped. Disc brake ( 10 ) according to one of the preceding claims, characterized in that the coupling part ( 24 . 82 ) in the first and / or the second recess ( 20 . 60 ) is fitted by interference fit. Disc brake ( 10 ) according to claim 11 if appended to claim 9, characterized in that the return spring ( 22 ) and / or the pad back plate ( 16 ) each have a leadership extension ( 70 ), which in the first and / or in the second recess ( 20 . 60 ) and which is in contact with the slot ( 40 ) of the coupling part ( 24 . 82 ) is engaged, so that the coupling part ( 24 . 82 ) against rotation in the first and second recesses ( 20 . 60 ) is secured. Disc brake ( 10 ) according to one of claims 11 or 12, if dependent on claim 9, characterized in that the coupling part ( 24 ) has at least one end stop which is adapted to limit a distance over which the coupling part ( 24 ) in the second recess ( 60 ) is displaceable. Disc brake ( 10 ) according to one of the preceding claims, characterized in that the coupling part ( 24 . 82 ) Materialeinstückig is made of a metal sheet. Brake pad assembly ( 14 ) for a disc brake ( 10 ) according to one of the preceding claims, wherein the brake lining arrangement ( 14 ) a friction lining with a pad back plate ( 16 ) and a reset device ( 18 ), wherein the pad back plate ( 16 ) a first recess ( 20 ) and the reset device ( 18 ) at least one return spring ( 22 . 80 ), and wherein the return device ( 18 ) is adapted to a restoring force on the pad back plate ( 16 ) in order to move the friction lining back to a starting position after a deflection, characterized in that the brake lining arrangement ( 14 ) at least one coupling part ( 24 . 82 ), which is substantially perpendicular to a surface of the pad back plate (FIG. 16 ) through the first recess ( 20 ) and is engaged with this under radial bias, wherein the coupling part ( 24 . 82 ) with the first recess ( 20 ) is engaged under radial bias, so that between the coupling part ( 24 . 82 ) and the inner peripheral surface of the first recess ( 20 ) one by bias of the coupling part ( 24 . 82 ) acting against the inner peripheral surface friction force acts, wherein the coupling part ( 24 . 82 ) is adapted to the reset device ( 18 ) with the pad back plate ( 16 ), and wherein the coupling part ( 24 . 82 ) is arranged, along its longitudinal direction in the first recess ( 20 ) to slide when the resistance of the return device against the deflecting movement exceeds the friction force, so that the pad back plate ( 16 ) relative to the coupling part ( 24 . 82 ) is displaceable for wear compensation.

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