DE102018122011A1 - Disc brake for a motor vehicle and method for detecting a braking torque of a disc brake - Google Patents

Abstract

A disc brake for a motor vehicle, in particular for a commercial vehicle, has a brake disc (4) with at least one friction ring (41, 42), at least one brake pad (5), an application device (6) with which the at least one brake pad (5) can be pressed onto the brake disc (4) while exerting a braking torque on the brake disc (4), a brake carrier (2) encompassing the brake disc (4) with at least one lining shaft, each having two carrier horns (23, interconnected by a bridge (22) 24), a measuring device with at least one measuring element (7) and an evaluation unit (8) coupled to this for determining the braking torque exerted on the brake disc (4) during a braking operation, the at least one measuring element (7) being arranged on the brake carrier (2) The braking torque exerted during the braking process can be calculated in the evaluation unit (8) from the deformation of the brake carrier (2) measured with the measuring device. Furthermore, a method for detecting a braking torque is described.

Description

The present invention relates to a disc brake for a motor vehicle, in particular a commercial vehicle according to the preamble of claim 1 and a method for detecting a braking torque of such a disc brake.

Disc brakes of the generic type are used in particular in motor vehicles and particularly in commercial vehicles in order to brake the vehicles. Disc brakes of this type usually consist of a brake disc with one or two friction rings, to which brake pads are pressed during a braking process, a floating application unit and a brake carrier with which the disc brake is fastened, for example screwed, to an axle of a vehicle.

For more precise control of such a disc brake, in particular for automated driving functions, it is advantageous to know the exact performance of the brake, in particular the braking force or the braking torque. However, knowledge of the clamping force or the actuation pressure is not sufficient. For the efficient design of highly automated driving functions such as platooning, i.e. To ensure the distance between column participants of a group of vehicles traveling in a column, knowledge of the braking force, braking torque or coefficient of friction is crucial.

For example, it is from the WO 2014/184112 A1 Known to determine a torque between a brake disc of the disc brake and an adapter flange for fixing the brake disc to a hub of the vehicle using a measuring module that measures the acting tangential force.

From the DE 196 50 477 C1 it is known to attach a measuring hub to a wheel axle of a motor vehicle, which is divided into two parts, one part being attached to the wheel axle and a second part holding the brake disc. The two parts of the measuring hub are connected to one another by radially extending webs. Sensors are applied to these radial webs with which the bending stress acting on the webs during the braking process due to the introduction of a torque can be measured.

The object of the present invention is to provide a disc brake and a method for detecting a braking torque of a disc brake, with which braking torques are made possible in an economical manner using established measurement methods.

This object is achieved by a disc brake with the features of claim 1.

The object is further achieved by a method for detecting a braking torque with the features of claim 11.

The disc brake according to the invention for a motor vehicle, in particular for a commercial vehicle, has a brake disc with at least one friction ring and at least one brake pad. The disc brake also has an application device with which the at least one brake pad can be pressed onto the brake disc while exerting a braking torque on the brake disc.

The disc brake also has a brake carrier encompassing the brake disc with at least one lining shaft. The brake carrier each has two carrier horns connected to one another by a bridge.

A measuring device of the disc brake with at least one measuring element and an evaluation unit coupled to it serves to determine the braking torque exerted on the brake disc during a braking operation.

The at least one measuring element is arranged on the brake carrier, the braking torque exerted during the braking process being calculable in the evaluation unit from the deformation of the brake carrier measured with the measuring device.

With a disc brake designed in this way, the applied braking torque can be determined in a braking process via a deformation on the brake carrier.

By using the determined braking torque as a controlled variable for controlling the braking process, additional influencing parameters, such as mechanical hysteresis or fluctuations in the coefficient of friction, can also be eliminated, since such parameters are already included or taken into account in the calculated braking torque.

The use of an expensive measuring hub, which is only suitable for experimental purposes, is also not necessary in the disk brake according to the invention.

Advantageous embodiments of the invention are the subject of the dependent claims.

According to an advantageous embodiment variant of the invention, the measuring element is designed as a strain gauge or resistance wire.

Such strain gauges or resistance wires are inexpensive and can be attached to the brake carrier in a simple manner.

According to a further embodiment variant, at least one measuring element is attached to an inner wall of a bore extending in the longitudinal direction of the bridge in the brake carrier.

With the help of the at least one measuring element, deformations on the bore wall can be measured. A map for different braking forces can be created from the determined deformations.

Since the measured deformation on the bore wall is proportional to the applied braking force or the applied braking torque, the applied braking torque can be calculated in a simple manner in the evaluation unit.

According to an alternative embodiment variant, at least one measuring element is attached to an inner wall of a bore in the brake carrier which extends in the longitudinal direction of one of the disc overlaps of the brake carrier. The deformation of the disc overlap is also suitable to calculate back to the applied braking torque.

The evaluation unit is preferably attached to the disc overlap of the brake carrier and is coupled to the at least one measuring element in a wireless or wired manner.

According to a further embodiment variant, in each case one measuring element is arranged in a recess between the support horns and support surfaces extending towards the bridge of at least one of the covering shafts, with a deformation between the two recesses being detectable by the two measuring elements which are wired or wirelessly coupled to one another via the evaluation unit.

The deformation between the spaced-apart measuring points of the cutouts in a respective lining shaft are also proportional to the braking torque applied, so that this deformation can also be used to calculate back to the applied braking torque in a simple manner.

According to yet another alternative embodiment, a measuring element is arranged on an underside of at least one of the bridges facing away from the support surfaces. The measuring element, which is preferably designed as a strain gauge, extends in the longitudinal direction of the bridge.

According to a further embodiment variant of the invention, a measuring element, which extends in the longitudinal direction of one of the disc overlaps, is attached to an outer wall or a recess of the brake carrier formed therein.

According to a preferred embodiment variant, this measuring element is screwed onto the outer wall or recess of the brake carrier formed therein, a connecting line between the screwing points being aligned parallel to a vertical axis of the brake.

The deformation of such a transverse bore or recess in the outer wall or the outer wall itself is proportional to the amount of braking force that is supported in the brake carrier, so that the deformation that is detected in this way can also be used to calculate back to the applied braking torque.

According to a further preferred embodiment of the disk brake according to the invention, in which the brake carrier has two lining shafts arranged parallel to one another in the direction of the axis of rotation of the brake disk, between which the brake disk is received, a measuring element is arranged between a respective one of the carrier horns of both lining shafts in order to shift the carrier horns relative to each other, which is proportional to the applied braking torque.

In the method according to the invention for detecting a braking torque of a disc brake, a deformation of the brake carrier when the brake is actuated is measured in a first method step using a measuring device arranged on the brake carrier. In a second step, the measured values are evaluated as the braking torque of the disc brake in the evaluation unit.

• 1 eine schematische Draufsicht auf einen Ausschnitt einer Ausführungsvariante einer erfindungsgemäßen Scheibenbremse mit schematisch angedeutetem Messelement zwischen zwei Trägerhörnern des Bremsträgers,
• 2 eine schematische perspektivische Ansicht einer alternativen Ausführungsvariante mit an einem Scheibenübergriff angeordneter Auswerteeinheit,
• 3 eine Schnittansicht der in 2 gezeigten Ausführungsvariante zur Darstellung einer sich in Längserstreckung einer Brücke erstreckenden Querbohrung zur Aufnahme wenigstens eines Messelements,
• 4 eine schematische Draufsicht auf eine weitere Ausführungsvarianten einer erfindungsgemäßen Scheibenbremse mit in Aussparungen zwischen einem Trägerhorn und einer Auflagefläche des Bremsträgers angeordneten Messelementen,
• 5 eine schematische perspektivische Ansicht von unten auf eine alternative Ausführungsvariante mit an einer Unterseite einer der Brücken angebrachtem Messelement,
• 6 eine Draufsicht auf eine alternative Ausführungsvariante einer Bremsscheibe einer Scheibenbremse mit auf einem Scheibenübergriff angeordneter Messelement,
• 7 und 8 unterschiedliche perspektivische Ansichten einer weiteren Ausführungsvariante einer Scheibenbremse mit in einer sich durch den Scheibenübergriff erstreckenden Bohrung angeordnetem Messelement, und
• 9 ein schematisches Flussdiagramm eines erfindungsgemäßen Verfahrens.

Preferred exemplary embodiments of the invention are explained in more detail below with reference to the accompanying drawings. Show it:

• 1 1 shows a schematic plan view of a section of an embodiment variant of a disc brake according to the invention with a schematically indicated measuring element between two carrier horns of the brake carrier,
• 2nd 2 shows a schematic perspective view of an alternative embodiment variant with an evaluation unit arranged on a pane overlap,
• 3rd a sectional view of the in 2nd Design variant shown to illustrate a transverse bore extending in the longitudinal extent of a bridge for receiving at least one measuring element,
• 4th 2 shows a schematic top view of a further embodiment variant of a disc brake according to the invention with measuring elements arranged in recesses between a carrier horn and a support surface of the brake carrier,
• 5 2 shows a schematic perspective view from below of an alternative embodiment variant with a measuring element attached to an underside of one of the bridges,
• 6 2 shows a plan view of an alternative embodiment variant of a brake disc of a disc brake with a measuring element arranged on a disc overlap,
• 7 and 8th different perspective views of a further embodiment variant of a disc brake with a measuring element arranged in a bore extending through the disc overlap, and
• 9 a schematic flow diagram of a method according to the invention.

In the following description of the figures, terms such as top, bottom, left, right, front, rear, etc. refer exclusively to the exemplary representation and position of the brake carrier, the brake pad, the carrier horns, the bridge, the measuring elements, and the evaluation unit selected in the respective figures and the same. These terms are not to be understood as restrictive, i.e. these references can change due to different working positions or the mirror-symmetrical design or the like.

In 1 is with the reference symbol 2nd a brake carrier for a pneumatically or electromotively actuated disc brake of a motor vehicle, in particular a commercial vehicle.

The brake carrier 2nd has a connection area which is used for fixing to a vehicle axle, for example by screwing to an axle flange of a vehicle axle of the commercial vehicle.

A lining shaft is formed above the connection area, which is used to receive and support at least one brake lining 5 serves.

The brake carrier shown here 2nd has two such covering shafts. The brake carrier 2nd is designed so that it is a brake disc 4th engages the disc brake, being on both sides of the brake disc 4th one pad shaft each to hold a respective brake pad 5 is molded.

As in 1 is shown, the disc brake also has a brake caliper 3rd on that on the brake carrier 2nd is slidably mounted and a portion of the brake disc 4th spreads

Each of the covering shafts will be, as in 4th represented by an inlet-side carrier horn 23 , 24th , a discharge horn on the outlet side 23 , 24th and one the carrier horns 23 , 24th connecting bridge 22 educated.

The carrier horns 23 are on one of the application devices 6 close application side of the brake carrier 2nd arranged. Accordingly, the side of the brake carrier 2nd on which the carrier horns 24th are arranged as the reaction side of the brake carrier 2nd designated.

The to the carrier horns 23 , 24th adjacent areas of the bridge 22 form contact surfaces 25th that of the radial support of the brake pad 5 serve with a bottom of the brake pad 5 when installed on the support surfaces 25th lies on.

To determine the on the brake disc 4th braking torque acting in the 1 to 8th Embodiments shown a measuring device with at least one measuring element 7 and an evaluation unit coupled to this 8th used, the at least one measuring element 7 on the brake carrier 2nd is arranged.

In the evaluation unit 8th is from the deformation of the brake carrier measured with the measuring device 2nd the braking torque exerted during braking can be calculated.

So with the in 1 shown embodiment variant a measuring element preferably designed as a strain gauge or resistance wire 7 between a tensioning horn and a reaction horn 23 , 24th arranged.

Both the connection of the carrier horns on the outlet side and the carrier horns on the inlet side are conceivable 23 , 24th . About such a measuring element 7 is the displacement between the action-side and the reaction-side carrier horn 23 , 24th detectable.

Because the deformation of the brake carrier 2nd is proportional to the braking torque applied in this area, the braking torque applied can be calculated from this.

In the 1 Evaluation unit (not shown) can also be arranged in the area of the brake carrier, but an arrangement of the evaluation unit at another location of the motor vehicle is also conceivable.

At the in 2nd The embodiment variant shown is from an area to the side of a lining shaft of the brake carrier 2nd from a disc overlap spanning the brake disc3 21 , which connects two facing shafts, a hole in the direction of the bridge 22 of the brake carrier 2nd brought in.

In this hole is on an inner wall of the hole 27 at least one measuring element 7 , preferably two or four measuring elements 7 appropriate.

The measuring element 7 or the multiple measuring elements 7 are preferably designed as strain gauges which extend in the longitudinal direction of the bore 27 extend.

For fixing the at least one measuring element 7 is in the area of the at least one measuring element 7 preferably an adhesive is introduced into the bore.

To the hole opening on the disc overlap 21 a cylindrical element is preferably used to fix the at least one measuring element 7 in the back of the hole 27 serves.

On the window overlap 21 is the evaluation unit in the embodiment variant shown here 8th attached.

The evaluation unit 8th is according to an embodiment variant with the at least one measuring element 7 connected by a cable.

A wireless coupling of the at least one measuring element is also conceivable 7 with the evaluation unit 8th .

With this structure, deformations on the inner wall of the bore 27 by means of the one or more measuring elements 7 be captured in a simple manner.

To accommodate the evaluation unit 8th is in the preferred embodiment shown here a housing of the evaluation unit 8th adapted recess in the outer surface of the window overlap 21 brought in.

The hole 27 with inner walls 28 and measuring elements attached to it 7 is also in 3rd shown.

At the in 4th Design variant of the disc brake shown are two measuring elements 7 via the evaluation unit 8th are coupled together in a recess 26 between the carrier horns 23 and to the bridge 22 extending support surfaces 25th at least one of the covering shafts arranged, with the two via the evaluation unit 8th wired or wirelessly coupled measuring elements 7 a deformation between the two recesses 26 is detectable.

It is also conceivable for the measuring elements 7 in the recesses 26 the reaction-side lining shaft between the carrier horns 24th and the contact surfaces 25th bring in.

The measuring elements 7 are also preferably designed as strain gauges. The measuring elements 7 are preferably protected by a housing from external environmental influences in the cutouts 26 used. This housing is in the respective recess 26 of the brake carrier 2nd fixed.

At the in 5 The variant shown is a measuring element 7 , preferably in the form of a strain gauge, on one of the bearing surfaces 25th opposite bottom of at least one of the bridges 22 arranged.

Because the brake carrier 2nd deformed as a function of the applied braking force in the area of the bridge, a deformation can also be detected in this area by application of a measuring element and thereby on the braking force associated with the deformation of the brake carrier 2nd related, will be calculated.

The measuring element 7 is preferably glued, screwed or welded to the bridge.

In addition, the measuring element 7 also be covered at the bottom by a housing to protect it from the harsh environmental conditions.

At the in 6 The variant shown is a measuring element 7 on an outer wall or a recess of one of the pane overlaps formed therein 21 of the brake carrier 2nd appropriate. The measuring element 7 extends in the longitudinal direction of the disc overlap 21 , parallel to the axis of rotation of the brake disc 3rd .

The measuring element 7 is preferred in the embodiment shown here using screws 11 on the surface of the disc overlap 21 screwed on.

The connecting line between the screwing points is preferably aligned parallel to a vertical brake axis. As further in 6 is recognizable is the measuring element 7 about a cable 12th with the side of the brake carrier 2nd attached evaluation unit 8th connected.

In the in the 7 and 8th The variant shown is the measuring element 7 not on the disc overlap 21 applied, but in a parallel to the axis of rotation of the brake disc 4th extending cross hole 29 added. One end of the measuring element 7 is with the side of the brake carrier 2nd attached evaluation unit 8th connected.

Also a deformation in the area of the disc overlap 21 is proportional to the braking torque introduced into the braking system. The deformation is also here, for example, with measuring elements designed as strain gauges 7 or at least one such measuring element 7 detected.

The deformation is preferred between the screwing points of the screws 11 detected.

9 shows schematically a flow chart of a method according to the invention for detecting a braking torque of a disc brake, in one step S1 a deformation of the brake carrier 2nd the disc brake is measured when the brake is actuated using a measuring device arranged on the disc brake.

The measurement can be carried out in different ways, as described above.

In a second step S2 these measured values are evaluated to calculate a braking torque of the disc brake 1 in the evaluation unit.

Reference list

2nd

Brake carrier

21

Disc overlap

22

bridge

23

inner support horn

24th

outer horn

25th

Base contact surface

26

Recess

27

drilling

28

Interior wall

29

Cross hole

3rd

Brake caliper

4th

Brake disc

41

first friction ring

42

second friction ring

5

Brake pad

6

Application device

7

Measuring element

8th

Evaluation unit

9

Fixing element

10th

adhesive

11

screw

12th

electric wire

S1

step 1

S2

step 2nd

D

Axis of rotation

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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.

Patent literature cited

• WO 2014/184112 A1 [0004]
• DE 19650477 C1 [0005]

Claims (11)

Disc brake for a motor vehicle, in particular for a commercial vehicle, comprising a brake disc (4) with at least one friction ring (41, 42), at least one brake pad (5), an application device (6) with which the at least one brake pad (5) is attached to the Brake disc (4) can be pressed onto the brake disc (4) while exerting a braking torque, a brake carrier (2) encompassing the brake disc (4) with at least one lining shaft, each having two carrier horns (23, 24) connected to one another by a bridge (22) , A measuring device with at least one measuring element (7) and an evaluation unit (8) coupled to this for determining the braking torque exerted on the brake disc (4) during a braking operation, characterized in that the at least one measuring element (7) on the brake carrier (2) is arranged, in the evaluation unit (8) from the deformation of the brake carrier (2) measured with the measuring device, the braking torque exerted during the braking process b is predictable. Disc brake after Claim 1 , characterized in that the measuring element (7) is designed as a strain gauge or resistance wire. Disc brake after Claim 2 characterized in that at least one measuring element (7) is attached to an inner wall (28) of a bore (27) in the brake carrier (2) extending in the longitudinal direction of the bridge (22). Disc brake after Claim 2 , characterized in that at least one measuring element (7) is provided on an inner wall of a bore (29) in the brake carrier (2) which extends in the longitudinal direction of one of the disc overlaps (21). Disc brake after Claim 3 or 4th , characterized in that the at least one measuring element (7) is wired or wirelessly coupled to the evaluation unit (8) attached to a disc overlap (21) of the brake carrier. Disc brake after Claim 2 , characterized in that in each case a measuring element is arranged in a recess (26) between the support horns (23, 24) and support surfaces (25) extending towards the bridge (22) of at least one of the covering shafts, with the two using the evaluation unit ( 8) measuring elements (7) which are wired or wirelessly coupled to one another, a deformation between the two cutouts (26) can be detected. Disc brake after Claim 2 characterized in that a measuring element (7) is arranged on an underside of at least one of the bridges (22) facing away from the bearing surfaces (25). Disc brake after Claim 2 , characterized in that a measuring element (7) extending in the longitudinal direction of one of the disc overlaps (21) is attached to an outer wall or recess of the brake carrier (2) formed therein. Disc brake after Claim 8 , characterized in that the measuring element (7) is screwed onto the outer wall or the recess of the brake carrier (2) formed therein, a connecting line between the screwing points being aligned parallel to a vertical axis of the brake. Disc brake after Claim 2 , wherein the brake carrier (2) has two lining shafts arranged parallel to one another in the direction of the axis of rotation of the brake disc (4), between which the brake disc (4) is accommodated, characterized in that a measuring element (7) between a respective one of the carrier horns (23, 24) of both lining shafts is arranged in order to detect a displacement of the carrier horns (23, 24) relative to one another which is proportional to the braking torque applied. Method for detecting a braking torque of a disc brake according to Claim 1 , characterized by the following method steps: (S1) measuring a deformation of the brake carrier (2) of the disc brake when the brake is actuated using a measuring device arranged on the brake carrier (2); and (S2) evaluating the measured values as braking torque of the disc brake (1) in the evaluation unit.

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