EP3924634A1

EP3924634A1 - Disc brake with a wear sensor device, method for determining the wear of brake linings and the brake disc of a disc brake, and method for monitoring the brake actuation and the resetting of a disc brake

Info

Publication number: EP3924634A1
Application number: EP20702115.5A
Authority: EP
Inventors: Josef ATZINGER; Erwin Pletz; Andreas Petschke; Florian Plettl
Original assignee: Knorr Bremse Systeme fuer Nutzfahrzeuge GmbH
Current assignee: Knorr Bremse Systeme fuer Nutzfahrzeuge GmbH
Priority date: 2019-02-15
Filing date: 2020-01-24
Publication date: 2021-12-22
Also published as: WO2020164885A1; DE102019103827B4; DE102019103827A1

Abstract

The invention relates to a disc brake for a utility vehicle, comprising a brake caliper which covers a brake disc, two brake linings arranged in the brake caliper, at least one resetting device, by means of which the brake linings can be reset after a brake-related movement and release of the disc brake and by means of which the brake caliper can be centered, a wear adjustment device for adjusting the wear of the brake linings and the brake disc, and a wear sensor device (16). The resetting device (10) has the wear sensor device (16). The invention also relates to a method for determining the wear of brake linings and the brake disc and to a method for monitoring the brake actuation and the resetting of a disc brake.

Description

DESCRIPTION

Disc brake with a wear sensor device,

Method for determining wear of brake linings and brake discs of a disc brake, and

Method for monitoring brake actuation and resetting of a disc brake

The invention relates to a disc brake with a wear sensor device according to the preamble of claim 1. The invention also relates to a method for determining wear of brake linings and brake disc and a method for monitoring brake actuation and resetting of a disc brake.

Disc brakes are now standard equipment in heavy commercial vehicles. Such disc brakes can be provided with so-called jerk adjusting devices.

Such disc brakes are usually compressed air operated and equipped with automatically acting, mechanical wear adjustment devices. These wear adjustment devices work very reliably and reduce a clearance that has become too large. They are known in different designs, e.g. mechanical adjuster with automatic adjustment of a friction point. With each brake application the adjusting device, e.g. activated by a feed element of an application device of the disc brake. If the brake linings and the brake disc wear, the linings are automatically readjusted using the wear adjustment device, e.g. through an adjustment movement of variable-position threaded spindles.

DE 10 2016 104 970 A1 describes a disc brake for a utility vehicle, with a brake caliper that overlaps a brake disc and is designed as a sliding caliper, is attached to a stationary brake carrier and has a central opening above the brake disc. The brake disc comprises two brake linings arranged in the brake caliper, movable in opposite directions, each having a lining carrier plate and a friction lining fastened thereon, one of which is on the action side by means of an application device via at least one NEN brake plunger can be pressed against the brake disc, as well as at least one restoring device with which the brake caliper can be returned after a braking-related shifting and releasing of the brake, the restoring device being a spreading device that acts on the opposing brake linings and acts in the same way against the respective application direction Has lining carrier plate engaging resilient expansion elements. The spreading device is arranged in the central opening, with the spreading elements acting directly or indirectly outside the friction linings on one side in the middle area or on at least two contact areas of the brake linings arranged at a distance from one another, the contact areas each having a contact surface and a contact surface on which the spreading elements are movably arranged.

DE 40 41 318 A1 describes a lining wear indicator for disc brakes of commercial vehicles that can be actuated by pressure medium, preferably pneumatically. An actuator, e.g. used in the form of an adjustment spindle in order to convert rotational movements of the adjustment spindle triggered during wear adjustment by means of a rotary encoder arrangement into signals which show the wear of the brake linings of the disc brake by means of evaluation electronics and based on the geometric dependency of the axial travel on the pitch and angle of rotation of the adjustment spindle.

In the course of simplifications and cost savings while maintaining or improving quality, there is a constant need for improved disc brakes.

It is therefore the object of the invention to provide a disc brake with an improved wear sensor device.

The invention is based on the further object of a method for determining wear of brake linings and brake discs and a

Specify a method for monitoring a brake actuation and a reset of a disc brake.

The object is achieved by a disc brake with the features of claim 1. The other objects are each achieved by a method having the features of claims 12 and 14.

A disc brake according to the invention for a commercial vehicle comprises a brake caliper that engages over a brake disc, two brake linings arranged in the brake caliper, and at least one restoring device with which the brake linings can be returned and the brake caliper can be centered after a brake-related shifting and releasing of the disc brake, a wear adjustment device for Adjustment of wear of the brake pads and the brake disc and a wear sensor device. The reset device has the wear sensor device.

This has the advantage that no cost-intensive gears are required to convert rotary movements to a wear sensor.

A method according to the invention for determining the wear of brake linings and brake discs of a disc brake for a commercial vehicle, the disc brake having a brake caliper that overlaps a brake disc, two brake linings arranged in the brake caliper, and at least one restoring device with which the brake linings are displaced and released after braking Disc brake are retractable and the brake caliper can be centered, has a wear adjustment device for adjusting wear of brake pads and brake disc and the wear sensor device described above, is carried out in such a way that the wear sensor device uses a distance between sleeve elements of the reset device that changes depending on the wear of brake pads and brake disc of a sensor element, wherein the sensor element converts the distance thus detected into an electrical value and / or into an electrical signal, wherein the electrical value representing the wear and / or the electrical signal are evaluated in an evaluation unit in such a way that the evaluation unit calculates and outputs the associated total wear.

In this way, an advantageously simple determination of the wear can be made possible.

It is advantageous if the evaluation unit outputs a warning signal during evaluation when a previously defined wear limit value is exceeded. A method according to the invention for monitoring a brake actuation and resetting of a resetting device of a disc brake for a commercial vehicle, the disc brake having a brake caliper that engages over a brake disc, two brake linings arranged in the brake caliper, and at least one resetting device with which the brake linings are displaced and released after braking the disc brake are retractable and the brake caliper can be centered, has a wear adjustment device for adjusting the wear of the brake linings and the brake disc and the above-mentioned wear sensor device, is carried out in such a way that the wear sensor device has a distance between, which changes depending on a brake actuation and / or a reset of a reset device Sleeve elements of the resetting device detected by means of a sensor element, the sensor element converting the distance thus detected into an electrical value or r / and converts it into an electrical signal, the electrical value and / or the electrical signal representing the resetting of the resetting device) being evaluated in an evaluation unit in such a way that the evaluation unit compares the brake actuation or / and the resetting of the resetting device previously specified values monitored.

Here, an advantageously simple monitoring of a brake actuation and a reset of a reset device of a disc brake can be achieved.

A method according to the invention for determining the wear of brake linings and brake discs of a disc brake for a commercial vehicle, the disc brake having a brake caliper that overlaps a brake disc, two brake linings arranged in the brake caliper, and at least one restoring device with which the brake linings are displaced and released after braking Disc brake are retractable and the brake caliper can be centered, has a wear adjustment device for adjusting wear of brake pads and brake disc and the above-described wear sensor device, is carried out in such a way that the wear sensor device has a distance between sleeve elements of the reset device that changes depending on the wear of brake pads and brake disc detected by means of an optical display, the distance representing the wear being displayed on the basis of line marks, arrow marks and / or scales. This is an advantageously simple method of measuring wear. Such a method can also be carried out in addition to the methods given above. If the evaluation unit issues a warning signal during evaluation when a previously defined wear limit value is exceeded, a simple monitoring display is made possible.

A preferred embodiment of a disc brake, wherein the brake caliper is designed as a sliding caliper and is slidably attached to the stationary brake carrier, the brake linings each having a lining carrier plate and a friction lining fastened thereon, a brake lining on the action or application side being able to be pressed against the brake disc by means of an application device, the restoring device having a retaining bracket and pairs of spring arms attached to the retaining bracket, the retaining bracket being attached to the brake carrier, the two pairs of spring arms attacking the respective pad carrier plate of the opposing brake pads against the respective application direction, and the two Pairs of spring arms are attached displaceably guided by means of sleeve elements on a straight central section of the retaining bracket, provides that the wear sensor device is a distance between the displaceable sleeve elements in the longitudinal direction de s captured straight middle section of the retaining bracket.

It has been found that the distance between the displaceable sleeve elements can be used as a measure of the wear on the brake linings and the brake disc. In this way, an advantageously simple wear sensor device can be used.

In one embodiment, the wear sensor device has at least one sensor element which converts the detected distance into an electrical value and / or into an electrical signal. Commercially available, cost-effective components of high quality are suitable for this.

Thus, the at least one sensor element can be a switch / button contact that can be used as a functional component in different designs. Simple wire contacts can also be used advantageously.

The at least one sensor element can also be a variable electrical resistor. This is advantageous as the value always set in each case can be retrieved again and does not require any energy to supply a data memory. For example, the changeable electrical resistance can be a slide potentiometer or a membrane potentiometer. The membrane potentiometer also offers the advantage of a sealed component.

In another embodiment, the at least one sensor element can be an inductive or capacitive sensor. Functional groups customary on the market can advantageously be used here. It is also possible in a further embodiment that the switch contact can serve to detect a wear limit value in addition to the other sensor elements.

Another embodiment provides that the wear sensor device is connected to an evaluation unit, the evaluation unit being designed to evaluate the electrical value and / or the electrical signal of the at least one sensor element as a wear value. It is thus advantageously possible to evaluate the distance between the sleeve elements for a measure of wear.

In a further embodiment, the wear sensor device has a housing and is attached to the retaining bracket. This results in a compact structure and requires little installation space. Thus, the wear sensor device can be attached with a holder in the middle of the central section of the holding bracket, which is advantageously possible in a simple manner.

In an alternative embodiment, the wear sensor device has two housing parts which engage in one another telescopically, are displaceable relative to one another and at the same time are arranged displaceably on the middle section of the retaining bracket between the sleeve elements. A particularly space-saving and compact structure can thus be achieved. In an alternative embodiment, the wear sensor device can have an optical display which shows the distance between the displaceable sleeve elements in the longitudinal direction of the straight central section of the retaining bracket. This is advantageously simple to produce and with the least amount of additional effort. Here, the optical display can have at least one marking in the form of line marks, which are attached to the central section of the retaining bracket and correspond to a wear value of the brake linings and the brake disc. In this way, a particularly simple reading of the total wear is possible by comparing the position of the end walls of the sleeve elements in relation to the line marks of the marking. A wear limit value can, for example, be shown in color or by a special line mark, for example twice. When the distance between the sleeve elements has reached the marked wear limit value, it is easy to check whether there is still sufficient wear volume of the friction linings, since the wear sensor device is visually checked directly above the brake linings.

The line marks can be scratched or etched in, for example. The optical display can also have a ring with or without a magnifying glass in order to simplify reading.

In a further embodiment, it is advantageous if the optical display has at least one arrow mark and a scale, a value displayed on the scale or a mark arranged on the scale corresponding to a wear value of the brake linings and the brake disc. In this way, reading accuracy can be increased.

The wear sensor device in connection with the reset device results in a cost saving in comparison with a conventional wear potentiometer. In addition, monitoring of the resetting device and also of the clearance or an actuation stroke is made possible in a simple manner. In addition, an advantageous retrofitting of the wear sensor device is possible either separately for attachment to an existing reset device or together with a reset device.

Further advantageous developments of the invention are specified in the subclaims.

Embodiments of the invention are described below with reference to the accompanying drawings.

Show it: 1 shows a schematic, perspective partial view of an exemplary embodiment of a disc brake according to the invention with a reset device and a wear sensor device;

Fig. 2 is a schematic plan view of the disc brake according to

1 in a state of wear;

3 shows an exemplary schematic, perspective illustration of the resetting device;

4 shows an exemplary schematic, perspective illustration of the resetting device with the wear sensor device;

FIG. 5 shows an exemplary schematic, perspective illustration of the resetting device with a variant of the wear sensor device according to FIG. 4;

FIG. 6 shows an exemplary schematic partial sectional illustration of FIG

Variant of the wear sensor device according to FIG. 5; and

FIG. 7 shows an exemplary schematic, perspective illustration of the reset device with a further variant of the wear sensor device according to FIG. 4.

1 shows a schematic, perspective partial view of an exemplary embodiment of a disk brake 1 according to the invention with a restoring device 10 and a wear sensor device 16.

Coordinates x, y, z are used to facilitate orientation. The x-coordinate runs in the direction of travel of a vehicle, not shown, to which the disc brake 1 is assigned. The y-coordinate lies parallel to a brake disc's axis of rotation, and the z-coordinate indicates a height.

The disc brake 1 comprises a brake carrier 2, a brake caliper 3, two brake linings 4, 4 ′, a brake disc 8, a restoring device 10 and a wear sensor device 16. The disk brake 1 is fixedly attached via the brake carrier 2 to a vehicle to which the disk brake 1 is assigned, for example to an axle flange (not shown). The caliper 3 engages over the brake disc 8 and is based on the

Brake disk 8 axially in the direction of the brake disk axis of rotation, which is not shown but is easy to imagine and runs in the y-direction, attached to the brake carrier 2 so as to be displaceable. For this purpose, the brake caliper 3 is mounted on guide bars (not shown) which are connected to the brake carrier 2 which is held in place on the vehicle.

The brake caliper 3 comprises an application section 3a, a caliper back 3b and two tension struts 3c. The back of the saddle 3b is connected to the application section 3a at one end each with a tension strut 3c.

The application section 3a has an interior space in which an application device (not shown) of the disc brake 1 is arranged. This application device here has two application pistons 18, 19. Reference symbols with an apostrophe indicate components which are arranged on one side of the brake disk which faces the back of the caliper 3b.

The brake pad 4, which points to the application section 3a, is referred to as the application-side brake pad 4, and the other brake pad 4 ', which is arranged on the satellite back 3b, is called the rear or reaction-side brake pad 4'.

In the brake carrier 2 are brake pads 4, 4 'in so-called lining shafts between two brake carrier horns 2a, 2b; 2’a, 2’b arranged. The brake pads 4, 4 'can be pressed against the brake disc 8 on both sides in the event of braking. Each brake lining 4, 4 'has a lining carrier plate 5, 5' and a friction lining 6, 6 '. The friction lining 6, 6 'is attached to the side of the lining plate 5, 5' facing the brake disc and is pressed against the brake disc 8 when the brakes are applied.

A pad retainer 9 is arranged above the brake pads 4, 4 in the y-direction between the clamping section 3a and the back of the satellite 3b. The pad retainer presses with sections of its underside on pad retainer springs 7, 7 'of the brake linings 4, 4', whereby these are held in their lining shafts. The resetting device 10 comprises a retaining clip 11 with two legs 11a and 11b and two pairs of spring arms 12, 12 'attached to the retaining clip 11; 13, 13 ', which are also referred to as pressure arms.

The retaining bracket 11 is designed with a straight central section 11c spanning the brake disk 8 and angled retaining arms 11a and 11b adjoining it on both sides in the form of a “C”. At the free ends of the two holding arms 11a, 11b there is a respective one for the brake carrier horns 2a,

2b angled end portion (not designated) attached.

The respective end sections of the holding arms 11a, 11b are fastened in the stationary brake carrier horns 2a, 2b of the brake carrier 2 facing the application section 3a of the brake caliper 3 in a respective receptacle 2c. These fastening points are designed to be stationary on the stationary brake carrier 2.

On both sides of the retaining bracket 11 at right angles to the brake disc axis of rotation in the x direction above the brake disc 8 are the two pairs of spring arms 12, 12 '; 13, 13 'attached to the straight central section 11c of the retaining bracket 11 in a displaceably guided manner by means of sleeve elements 14, 15. This straight central section 11c of the retaining bracket 11 has a central axis 11d which runs in the x direction.

Each end of a spring arm 12, 12 '; 13, 13 ’of a pair stands with one recording each 5a, 5’a; 5b, 5'b in a respective end section 12a, 12'a; 13a,

13'a in engagement or interaction with opposite side end sections of the lining carrier plates 5, 5 'of the brake linings 4, 4'.

When the disc brake 1 is applied by actuating the application device, the application pistons 18, 19 are pressed against the lining carrier plate 5 of the brake lining 4 on the application side. In the further course of the braking process, the brake caliper 3, based on the brake disc 8, is now shifted against the application direction of the application-side brake pad 4, with the opposite, rear-side brake pad 4 'being carried along and pressed onto the other side of the brake disc 8.

During this application process, the two pairs of spring arms 12, 12 '; 13, 13 ', depending on the application path of the brake linings 4, 4', are compressed in the y-direction in the direction of the retaining bracket 11. This supply tension path is composed of the so-called clearance and a certain amount of compression of the friction linings 6, 6 '. The clearance is the distance between a friction lining 6, 6 ′ and the brake disk 8.

In other words, the spring arms 12, 13, which are in engagement with the lining carrier plate 5 of the application-side brake lining 4, are moved in the negative y-direction towards the retaining bracket 11 during an application process. In contrast, the spring arms 12 ’, 13’, which are in engagement with the lining carrier plate 5 ’of the rear brake lining 4’, are moved in the positive y-direction towards the retaining bracket 11. The two sleeve elements 14 and 15, which are slidably guided on the straight middle section 11c of the retaining bracket 11, move so that a distance 17 in the x direction, i.e. in the longitudinal direction of the straight central section 11c of the retaining bracket 11, between these sleeve elements 14 and 15 is changed as a function of a brake actuation. That is to say, the distance 17 is reduced during an application process and increased during a release process of the disc brake 1.

After the disc brake 1 is released, the two opposing brake pads 4, 4 'are moved so far away from the brake disc 8 by means of the resetting device 10 by means of the resilient, tensioned spring arms 12, 12'; 13, 13 'solved so that the brake disc 8 runs freely in relation to the brake pads 4, 4'. This prevents or at least considerably reduces a residual grinding torque. For this purpose, not only are the brake pads 4, 4 'actively reset by the brake disc 8, but the brake caliper 3 is also centered again, i.e. that an x-z plane of the brake disc 8 is aligned with an imaginary center line of an opening running in the x direction. This opening is defined by the application section 3a, the saddle back 3b and the tension struts 3c over the brake disc 8 and the brake pads 4, 4 '. The resetting device 10 thus has the two main functions of resetting the brake linings 4, 4 ′ and centering the brake caliper 3.

The reset device 10 engages here in the upper area of the lining carrier plates 5, 5 'of the opposing brake linings 4, 4' with the spring arms 12, 12 '; 13, 13 'have the same effect against the application direction, which runs in the y direction. In this way, the brake pads 4, 4 'are acted upon in their upper areas with restoring forces from the restoring device 10. In this case, the brake caliper 3 is centered over the rear-side brake pad 4 'which has been reset in this way, since the retaining bracket 11 of the reset device 10 is fixedly attached to the brake carrier 2.

! If the brake linings 4, 4 ', ie the friction linings 6, 6', and also the brake disc 8 are worn, the brake linings 4, 4 'are automatically readjusted by means of a wear adjustment device (not shown), for example by means of a rotating movement of variable-position threaded spindles, which with the application pistons 18, 19 are coupled. The application pistons 18, 19 can also have a corresponding thread. In this way, the brake linings 4, 4 'are advanced towards the brake disc 8 as a function of the wear that occurs such that a so-called clearance between the friction linings 6, 6' and the brake disc 8 can be kept constant. In this case, the application-side brake pad 4 is adjusted in the negative y-direction towards the brake disc 8, the rear-side brake lining 4 'being adjusted in the positive y-direction towards the brake disc 8.

With brake pads 4, 4 ’adjusted in this way, the two pairs of spring arms 12, 12’; 13, 13 'depending on the adjusted position of the brake pads 4, 4' pressed together in the direction of the retaining bracket 11. In other words, the spring arms 12, 13, which are in engagement with the lining carrier plate 5 of the application-side brake lining 4, are moved in the negative y direction towards the retaining bracket 11. In contrast, the spring arms 12 ’, 13’, which are in engagement with the pad carrier plate 5 ’of the rear brake pad 4’, are moved in the positive y-direction towards the retaining bracket 11. The two sleeve elements 14 and 15, which are guided displaceably on the middle section 11c of the retaining bracket 11, move in such a way that a distance 17 in the x direction between these sleeve elements 14 and 15 changes, here is reduced.

The wear sensor device 16 is designed to detect the distance 17 between the sleeve elements 14 and 15. For this purpose, the wear sensor device in the embodiment according to Fig. 1 is in the region of the central section 11c of the retaining bracket 11, e.g. between the sleeve elements 14 and 15 and / or coupled to these, arranged.

In a first embodiment, the wear sensor device 16 is designed in such a way that it determines the distance 17 between the sleeve elements 14, 15, which corresponds to a wear value at which a change of the brake linings 4, 4 'becomes necessary. This is explained in more detail below. In a further embodiment, the wear sensor device 16 detects or measures the distance 17 between the sleeve elements 14 and 15. The value of the distance 17 detected in this way then becomes a wear or a thickness of the friction linings 6, 6 'of the brake linings 4, 4' and the brake disk 8 is also calculated. In this way, the total wear of the brake linings 4, 4 'and the brake disc 8 can be determined and displayed.

Since, as described above, the distance 17 also changes as a function of a brake actuation, i.e. in an application process and a release process of the disc brake, the wear sensor device 16 is able to monitor the application process and the release process in yet another embodiment variant with a corresponding evaluation device (not shown). E.g. Too small or too large a clearance and also a function of the reset can be monitored by the reset device 10 and its function, e.g. How much or how far the brake pads 4, 4 'are pushed back by the resetting device 10 after the release process.

The wear sensor device 16 is explained in more detail below.

In Fig. 2 is a schematic plan view of the disc brake 1 according to FIG.

1 shown in a worn condition.

In the state of wear shown in Fig. 2, the friction linings 6, 6 'of the brake linings 4, 4' have reached a wear limit and must be replaced. It can be clearly seen that the application pistons 18, 19 are rotated / exposed far out of the application section 3a of the brake caliper 3 by the wear adjustment device (not shown) in order to maintain the clearance between the worn brake pads 4, 4 'and the brake disc 8.

The value of the distance 17, which is detected by the wear sensor device 16, corresponds to this wear limit value. For this purpose, the wear sensor device 16 in this example has an electrically conductive switch contact. The switch / push button contact is closed or opened when it is reached by mechanical actuation, the switch GT contact switching an electrical current as a signal on or off. This electrical current can then be used as a signal from an evaluation unit (not shown) be evaluated in such a way that a display is output, e.g. a warning lamp "Change brake pads" lights up.

The switch / button contact is e.g. arranged in a housing of the wear sensor device 16, which is only indicated schematically in FIGS. 1, 2. An actuation of the switch / button contact can e.g. by one of the two sleeve elements 14, 15 (or by both). For example, the switching contact can be a snap contact of a conventional limit switch, the actuator of which interacts with the associated sleeve element 14, 15.

The switching contact can also be an electrically conductive contact section, which is arranged in the housing of the wear sensor device 16 so as to be insulated from the vehicle mass and comes into electrically conductive contact with the associated sleeve element 14, 15 when the wear limit value is reached. The sleeve element 14, 15 stands e.g. permanently in electrically conductive contact with the vehicle ground, contact between the switching / pushbutton contact and the sleeve element 14, 15 being easily detectable and evaluated by a suitable evaluation device.

It is also conceivable that

FIG. 3 shows a schematic, perspective exemplary illustration of the resetting device 10.

The reset device 10 is shown in FIG. 3 in its non-installed state.

Each pair of spring arms 12, 12 ’; 13, 13 'is connected to a sleeve element 14, 15 each. The sleeve elements 14, 15 are guided displaceably on the straight central section 11c in the direction of the central axis 11d. The distance 17 is here the distance from the end faces 14a, 15a of the sleeve elements 14, 15 in the direction of the central axis 11d of the central section 11c of the retaining bracket 11. In the installed state of the resetting device 10 in the disc brake 1 (see FIG. 1), the central axis 11d runs in Essentially in the x direction.

FIG. 4 shows an exemplary schematic, perspective illustration of the resetting device 10 with the wear sensor device 16. The wear sensor device 16 has a housing 16a and is attached to the retaining bracket 11. In this example, the housing 16a is attached with a bracket 16b in the middle of the central portion 11c. This attachment position is not reached by the wear limit value, ie the distance 17 is still so large at the wear limit value that space remains for the positioning of the holder 16b on the middle section 11c. However, it is also possible that a holder of the housing 16b can be attached on both sides to the legs 11a, 11b which are bent downwards. This is not shown, but it is easy to imagine.

In this example, the wear sensor device 10 can be provided with the switching / push button contact described above.

It is also possible for a slide potentiometer (not shown, but easily conceivable) to be arranged in the housing 16a of the wear sensor device 10, an actuator of the slide potentiometer cooperating with a sleeve element 14, 15. It is also conceivable for two slide potentiometers to be provided, each with an actuator, with an actuator of a respective slide potentiometer being assigned to each sleeve element 14, 15.

The variable electrical resistance of the slide potentiometer is a measure of the distance 17 and can be measured and evaluated by a suitable evaluation circuit. The switching / push button contact can also be provided as limit value detection.

FIG. 5 shows an exemplary schematic, perspective illustration of the resetting device 10 with a variant of the wear sensor device 16 according to FIG. 4. FIG. 6 shows an exemplary schematic partial sectional illustration of the variant of the wear sensor device 16 according to FIG.

In this variant, the wear sensor device 16 has two housing parts which mesh telescopically, are displaceable relative to one another and at the same time are arranged on the central section 11c of the retaining bracket 11 so that they can be displaced between the end faces 14a, 15a of the sleeve elements 14, 15.

The two housing parts of the wear sensor device 16 comprise a sensor housing 20 and an actuator 21. In this example, the housing parts are le 20, 21 cylindrical with a circular cross-section, other cross-sections are of course also possible, such as rectangular tube, oval tube and the like.

The sensor housing 20 is coupled by an end wall 20a to the one sleeve element 15, e.g. the end wall 20a rests against the end wall 15a of the sleeve element 15. An end wall 20b of the sensor housing 20 opposite the end wall 20a has an opening of an interior space 20c of the sensor housing 20. This interior space 20c is here a bore which extends as far as the end wall 20a in the x direction and merges into a through opening 20e. The through opening 20e has a cross section which corresponds to the outer cross section of the central section 11c of the retaining bracket 11. The sensor housing 20 is pushed together with the sleeve element 15 onto the middle section 11c, the middle section 11c extending through the through opening 20e of the sensor housing 20.

The actuator 21 as the second housing part of the wear sensor device 16 is tubular here. It comprises an end wall 21a, an actuating end 21b and a through opening 21c. The end wall 21a is coupled to the other sleeve element 14, e.g. the end wall 21a rests against the end wall 14a of the sleeve element 14. The actuating end 21b is partially received in the interior space 20c of the sensor housing 20 and is displaceably guided therein in a manner not shown. The through opening 21c has a cross section which corresponds to the outer cross section of the central section 11c of the retaining bracket 11. The actuator 21, together with the sleeve element 14, is pushed onto the middle section 11c, the middle section 11c extending through the through opening 21c of the actuator 21.

In this example, a spring element 22 is arranged in the interior 20c of the sensor housing 20 between the inside of the end wall 20a and the actuating end 21b of the actuator 21, which, when the wear sensor device 16 is installed, the actuator 21 against the sleeve element 14 and the sensor housing 20 against the sleeve element 15 preloads.

In the interior space 20c of the sensor housing 20, at least one sensor element 23 is arranged, which interacts with an actuation section 24 of the actuator 21 at its actuation end 21b. If the distance 17 changes, the actuator 21 and the sensor housing 20 are displaced relative to one another. This displacement is detected by the sensor element 23 and transmitted here via an electrically conductive connection 25, for example a three-wire cable, to the evaluation unit, which is not shown but is easily conceivable.

The sensor element 23 here is a so-called membrane potentiometer, the electrical resistance of which can be adjusted by the actuating section 24 of the actuator 21 as a function of the distance 17.

The sensor element 23 can of course also be a conventional slide potentiometer.

It is also conceivable that the sensor element 23 and the actuation section 24 of the actuator 21 form an inductive or capacitive sensor.

An optical sensor can also be formed from the sensor element 23 and the actuating section.

The reset device 10 is delivered with the wear sensor device 16. The wear sensor device 16 is then connected to an evaluation unit by means of the connection 25. The evaluation unit can be designed separately or it can be a component part of on-board electronics or a brake control device of the vehicle assigned to the disc brake 1.

A method for determining the wear of brake linings 4, 4 'and brake disc 8 of disc brake 1 for a commercial vehicle is carried out as follows.

The wear sensor device 16 detects the distance 17 between the sleeve elements 14 and 15, which changes depending on the wear of the brake linings 4, 4 and brake disc 8, by means of a sensor element 23. The sensor element 23 converts the detected distance 17 into an electrical value and / or into electrical signal around. The electrical value representing the wear and / or the electrical signal are evaluated in an evaluation unit in such a way that the evaluation unit calculates and outputs the associated total wear. A method for monitoring the resetting device 10 and also the clearance or an actuation stroke of the disc brake 1 is carried out as follows.

The wear sensor device 16 detects the changing distance 17 between the sleeve elements 14 and 15 as a function of a brake actuation and / or a reset by means of a sensor element 23. The sensor element 23 converts the detected distance 17 into an electrical value and / or into an electrical signal . The electrical value representing the brake actuation or the reset and / or the electrical signal are evaluated in an evaluation unit in such a way that the evaluation unit monitors the brake activation and / or the reset in comparison with previously defined values.

In another embodiment, visual wear sensing can take place.

This is shown in FIG. 7 in an exemplary schematic, perspective illustration of the resetting device 10 with a further variant of the wear sensor device 16 according to FIG. 4.

The wear sensor device 16 can have an optical display which shows the distance 17 between the displaceable sleeve elements 14, 15 in the longitudinal direction of the straight central section 11c of the retaining bracket 11.

The wear sensor device 16 has a marking 26 in the form of e.g. Line marks (also colored), which are attached to the central section 11c of the retaining bracket 11. This marking 26 can e.g. be molded, e.g. engraved. The total wear is read off e.g. by comparing the position of the end walls 14a, 15a of the sleeve elements 14, 15 with respect to the line marks of the marking 26. A wear limit value can e.g. colored or by a special line mark, e.g. double, be shown. When the distance 17 of the sleeve elements 14, 15 has reached the marked wear limit value, it is easy to check whether there is still sufficient wear volume of the friction linings 6, 6 ', since the visual inspection of the wear sensor device 16 directly above the brake linings 4,

4 'takes place.

The optical display can also have at least one arrow mark and a scale, with a value displayed on the scale or one on the Scale arranged mark correspond to a wear value of the brake pads and the brake disc. This is not shown but is easy to imagine.

The sleeve elements 14, 15 shown in the figures are only exemplary; they can of course have a different configuration. For example, the sleeve elements 14, 15 from a wire winding of a connecting portion of the spring arms 12, 12 '; 13, 13 'be formed.

The components of the reset device 10, namely the retaining bracket 11 and the spring arms 12, 12 '; 13, 13 'are made in the examples shown from a wire with a circular cross-section. It is of course also possible for the wire to have a different cross-section or even several different cross-sections.

The resetting device 10 in connection with the wear sensor device 16 results in a cost saving in comparison with a conventional wear potentiometer. In addition, the resetting device 10 and also the clearance or an actuation stroke can be monitored in a simple manner.

The invention is not restricted by the exemplary embodiments given above, but can be modified within the scope of the claims.

For example, it is conceivable that the spring element 22 of the wear sensor device 16 can be omitted if the sleeve element 15 is firmly connected to the sensor housing 20 and the sleeve element 14 is firmly connected to the actuator 21.

REFERENCE LIST

1 disc brake

2 brake carriers

2a, 2b; 2’a, 2’b brake carrier horn

2c recording

3 calipers

3a application section

3b saddle back

3c tension strut

4, 4 'brake pad

5, 5 ’base plate

5a, 5b; 5’a, 5’b recording

6, 6 ’friction lining

7, r pad retaining spring

8 brake disc

9 pad retainer

10 reset device

11 retaining bracket

11a, 11b legs

11c middle section

11 d central axis

12, 12 '; 13, 13 'spring arm

12a, 12’a; 13’a, 13’b end section

14, 15 sleeve element

14a, 15a front side

16 wear sensor device 16a housing

16b bracket

17 distance

18, 19 clamping piston

20 sensor housings

20a, 20b end wall

20c interior

20d inner bulkhead

20e through opening

21 actuators

21a end of operation

21b front wall 21c through opening

22 spring element

23 sensor element

24 operating section

connection

26 Marking x, y, z coordinates

Claims

PATENT CLAIMS

1. Disc brake (1) for a commercial vehicle, with a brake caliper (3) which engages over a brake disc (8), two brake pads (4, 4 ') arranged in the brake caliper (3), and at least one restoring device (10) with which the brake linings (4, 4 ') are retractable and the brake caliper (3) can be centered after a braking-related shifting and releasing of the disc brake (1), a wear adjustment device for adjusting the wear of the brake linings (4, 4') and the brake disc (8) and a wear sensor device (16),

characterized in that

the resetting device (10) has the wear sensor device (16).

2. Disc brake (1) according to claim 1, wherein the brake caliper (3) is designed as a sliding caliper and is slidably attached to the stationary brake carrier (2), the brake pads (4, 4 ') each having a pad carrier plate (5, 5') and have a friction lining (6, 6 ') fastened thereon, an action-side or application-side brake lining (4) being able to be pressed against the brake disc (8) by means of an application device, the restoring device (10) having a retaining clip (11) and on the retaining clip ( 11) has attached pairs of spring arms (12, 12 '; 13, 13'), the retaining bracket (11) being fastened to the brake carrier (2), the two pairs of spring arms (12, 12 '; 13, 13') ) act on the respective pad carrier plate (5, 5 ') of the opposing brake pads (4, 4') against the respective application direction, and the two pairs of spring arms (12, 12 '; 13, 13') on a straight central section ( 11c) of the retaining bracket (11) by means of sleeve elements (14, 15) verschiebba r are attached,

characterized in that

the wear sensor device (16) detects a distance (17) between the displaceable sleeve elements (14, 15) in the longitudinal direction of the straight central section (11c) of the retaining bracket (11).

3. disc brake (1) according to claim 2,

characterized in that

the wear sensor device (16) has at least one sensor element (23) which converts the detected distance (17) into an electrical value and / or into an electrical signal.

4. disc brake (1) according to claim 3,

characterized in that

the at least one sensor element (23) is a switch / button contact.

5. disc brake (1) according to claim 3 or 4,

characterized in that

the at least one sensor element (23) is a variable electrical resistor.

6. disc brake (1) according to claim 3 or 4,

characterized in that

the at least one sensor element (23) is an inductive or capacitive sensor.

7. disc brake (1) according to one of claims 2 to 6,

characterized in that

the wear sensor device (16) is connected to an evaluation unit, the evaluation unit being designed as a wear value for evaluating the electrical value and / or the electrical signal of the at least one sensor element (23).

8. disc brake (1) according to one of the preceding claims,

characterized in that

the wear sensor device (16) has a housing (16a) and is attached to the retaining bracket (11).

9. disc brake (1) according to claim 8,

characterized in that

the wear sensor device (16) is attached with a holder (16b) in the middle of the central section (11c) of the retaining bracket (11).

10. disc brake (1) according to claim 8,

characterized in that

the wear sensor device (16) has two housing parts which mesh telescopically, are displaceable relative to one another and at the same time are arranged on the middle section (11c) of the retaining bracket (11) so that they can be displaced between the sleeve elements (14, 15).

11. Disc brake (1) according to one of claims 2 to 10, characterized in that

the wear sensor device (16) has an optical display which shows the distance (17) between the displaceable sleeve elements (14, 15) in the longitudinal direction of the straight central section (11c) of the retaining bracket (11).

12. disc brake (1) according to claim 11,

characterized in that

the optical display has at least one marking (26) in the form of line marks which are attached to the central section (11c) of the retaining bracket (11) and correspond to a wear value of the brake linings (4, 4 ') and the brake disc (8) .

13. Disc brake (1) according to claim 11 or 12,

characterized in that

the optical display has at least one arrow mark and a scale, with a value displayed on the scale or a mark arranged on the scale corresponding to a wear value of the brake linings (4, 4 ') and the brake disc (8).

14. A method for determining wear of brake linings (4, 4 ') and brake disc (8) of a disc brake (1) for a commercial vehicle, the disc brake (1) having a brake caliper (3) which engages over a brake disc (8), two Brake linings (4, 4 ') arranged in the brake caliper (3), as well as at least one resetting device (10) with which the brake linings (4, 4') can be returned after the disc brake (1) has been moved and released due to braking, and the brake caliper (3) can be centered, has a wear adjustment device for adjusting wear of brake linings (4, 4 ') and brake disc (8) and a wear sensor device (16) according to one of claims 1 to 10,

characterized in that

the wear sensor device (16) has a distance (17) between the sleeve elements (14 and 15) of the resetting device (10) that changes depending on the wear of the brake linings (4, 4 ') and brake disc (8) by means of a sensor element (23) detected, wherein the sensor element (23) converts the distance (17) detected in this way into an electrical value and / or into an electrical signal, the electrical value representing the wear and / or the electrical signal being evaluated in an evaluation unit in this way that the evaluation unit calculates and outputs the associated total wear.

15. The method according to claim 14,

characterized in that

the evaluation unit outputs a warning signal during evaluation if a previously defined wear limit value is exceeded.

16. A method for monitoring a brake actuation and resetting of a reset device (10) of a disc brake (1) for a commercial vehicle, the disc brake (1) having a brake caliper (3) which engages over a brake disc (8), two in the brake caliper (3) arranged brake pads (4, 4 '), as well as at least one restoring device (10), with which the brake pads (4, 4') can be returned and the brake caliper (3) can be centered after a braking-related displacement and release of the disc brake (1), a Ver - has wear adjustment device for adjusting wear of brake linings (4, 4 ') and brake disc (8) and a wear sensor device (16) according to one of claims 1 to 10,

characterized in that

the wear sensor device (16) detects a distance (17) between the sleeve elements (14 and 15) of the reset device (10), which changes depending on a brake actuation and / or a reset of a reset device (10), by means of a sensor element (23), the sensor element (23) converts the distance (17) detected in this way into an electrical value and / or into an electrical signal, the electrical value representing the resetting of the resetting device (10) and / or the electrical signal being evaluated in an evaluation unit in such a way that the evaluation unit monitors the brake actuation and / or the resetting of the resetting device in comparison with previously defined values.

17. The method according to claim 16,

characterized in that

the evaluation unit issues a warning signal during evaluation if a previously defined limit value is exceeded.

18. A method for determining wear of brake linings (4, 4 ') and brake disc (8) of a disc brake (1) for a utility vehicle, the disc brake (1) having a brake caliper (3) which engages over a brake disc (8), two brake pads (4, 4 ') arranged in the brake caliper (3), as well as at least one resetting device (10) with which the brake linings (4, 4 ') can be returned and the brake caliper (3) can be centered after a braking-related shifting and releasing of the disc brake (1), a wear adjustment device for adjusting the wear of the brake linings (4 , 4 ') and brake disc (8) and a wear sensor device (16) according to one of claims 1 to 13,

characterized in that

the wear sensor device (16) detects a distance (17) between the sleeve elements (14 and 15) of the resetting device (10), which changes depending on the wear of the brake linings (4, 4 ') and the brake disc (8), by means of an optical display by line marks, arrow marks and / or scales the distance (17) representing the wear is displayed.