WO2019170408A1

WO2019170408A1 - Lining wear sensor and brake lining

Info

Publication number: WO2019170408A1
Application number: PCT/EP2019/054115
Authority: WO
Inventors: Stephan Kotteder; Josef Schropp
Original assignee: Knorr-Bremse Systeme für Nutzfahrzeuge GmbH
Priority date: 2018-03-06
Filing date: 2019-02-19
Publication date: 2019-09-12
Also published as: DE102018105057B4; DE102018105057A1

Abstract

The invention relates to a lining wear sensor (1, 21) for arranging on or in a brake lining (2, 22) of a disk brake, comprising a fastening body (10, 30) and a contact conductor (20), the contact conductor (20) being connected to the fastening body (10, 30), wherein the fastening body (10, 30) is formed at least in regions from a cement-containing material. The invention also relates to a brake lining (2).

Description

DESCRIPTION

Pad wear sensor and brake pad

The invention relates to a lining wear sensor according to the preamble of

Claim 1 and a brake pad of a disc brake according to the preamble of claim 12.

The generic DE 10 2008 026 104 A1 describes a device for

Wear detection of a brake pad, so a generic

Pad wear sensor. For monitoring the friction lining thickness, in particular for determining a permissible wear limit of the friction lining of the brake lining, contact conductors are known, for example in the form of cables which, when the wear limit is reached, ie when the friction lining has worn away accordingly, comes into contact with the friction lining during braking standing brake disc

be sanded, whereby an electrical pulse is given to a signal generator. This indicates that the permissible wear limit of the brake pad has been reached and replacement is required.

Such a contact conductor is set in a generic device, which clamped as a holder in a friction lining bearing pad carrier plate of

Brake pads engages, wherein the plant leg through which, for example, the said cable is guided, rests in a recess of the friction lining and protrudes into it so far that the inserted cable to a predetermined thickness of the

Friction lining is positioned. When falling below the predetermined thickness of

Reibbelags the fogging sensor to indicate that the friction lining should be replaced.

Heretofore, a non-fusible aromatic polyimide has been used as the attachment body of the pad wear sensor. This polyimide has a

Heat resistance of more than 300 ° C and a high wear resistance, so that the wear values are matched to the material properties of the friction lining. The invention has for its object to provide an alternative attachment body for the pad wear sensor, which corresponds to the material requirements in the braking area and this even to improve compared to the material used to date even.

This object is achieved by a lining wear sensor having the features of claim 1 and a brake pad having the features of claim 12.

An inventive pad wear sensor for placement on or in a

Brake pad of a disc brake has a mounting body and a

Contact conductor element on.

The contact conductor element is connected to the attachment body. This may be an immediate connection, e.g. through an implementation of the

Contact conductor element in the mounting body or an outside wrapping of the contact conductor element to the mounting body, act. However, in the context of the present invention, an indirect connection is also possible. This would be e.g. when wrapping the mounting body with insulated cables, in which initially the insulation is removed as a result of abrasion or at

Contact conductor elements which are connected by fastening means (mechanical fasteners, adhesive, potting or the like) to the mounting body.

The connection may also be a fixed connection or a movable connection, so that the contact conductor element is arranged, for example, movable relative to the fastening body in a passage of the fastening body.

The attachment body has in particular an abrasion side, which is at least partially exposed to abrasion by a rotating brake body, such as a brake disc, from a certain service life of the brake pad at normal arrangement of the lining wear sensor on or in the brake pad. The abrasion side of the mounting body is inventively at least partially formed of a cement-based material.

The use of the cement-based material makes it possible to improve

Temperature stability and mechanical stability of the pad wear sensor at temperatures beyond 300 ° C.

Further advantageous embodiments of the invention are the subject of

Dependent claims.

In particular, the abrasion side region of the lining wear sensor can be used as

Sensor head be formed. In this sensor head, the contact conductor may be guided, wherein the sensor head consists of the cementitious material.

The attachment body is advantageously resiliently arranged on the brake pad, so that the elasticity of the material of a friction lining of the brake pad is compensated by the resilient mounting.

The lining wear sensor can advantageously have a spring element for resilient mounting of the mounting body on the brake pad. This direction of the suspension should preferably in Zuspannrichtung, ie in the direction of movement of the brake pad to the brake partner, e.g. to the brake disc, out or away.

To increase the mechanical strength, in particular the compressive and tensile strength, the cementitious material may be formed as a fiber-reinforced cementitious material.

For reasons of temperature stability and strength, the cementitious material may be formed as a UHPC material, more preferably as a HRUHPC material, in particular as a fiber reinforced HRUHPC material. The proportion of fibers in the cementitious material may advantageously be at least 1% by weight, preferably from 2 to 12% by weight.

The fibers of the fiber-reinforced cementitious material may be formed as non-conductive fibers, in particular as glass fibers and / or carbon fibers.

The proportion of cement in the cementitious material may advantageously be at least 10% by weight, preferably at least 25% by weight

In a particularly simple and cost-effective manner, the attachment body can be produced in a strand molding process.

The attachment body can be attached to a lining carrier plate of a brake pad,

in particular be detachable, plugged or plugged.

Hereinafter, an embodiment of the present invention will be explained in detail and with the aid of the accompanying figures. The invention is not limited to the embodiment. Thus, in a modification of the embodiment, a variety of embodiments can be realized. Individual features of the

Embodiment may be advantageous per se and used in other embodiments.

1 is a detail view of an embodiment of a lining wear sensor without contact conductor and its arrangement on a lining carrier plate.

Fig. 2 is a sectional view of the lining wear sensor of Fig. 1 and its

Arrangement on the lining carrier plate;

3 shows a tolerance sleeve;

4 shows a detailed view of a built-in tolerance sleeve; 5 shows a sectional view of a second variant of the invention

Pad wear sensor;

6 is a perspective view of a first side of the mounting body of the

Lining wear sensor of Fig. 5;

7 is a perspective view of a second side of the mounting body of the

Pad wear sensor of Figures 5 and 6;

Fig. 8 is a schematic representation of the Befestigungskorpuses of Fig. 5-7 of

Lining wear sensor in a lining carrier plate;

Fig. 9 is a perspective view of a plate spring for use in a

Pad wear sensor;

Fig. 10 brake pad with the pad wear sensor of Fig. 5-8;

Fig. 1 1 detail view of Fig. 10;

Fig. 12 rear view of the brake pad of Fig. 10; and

Fig. 13 is a perspective view of the pad wear sensor of Figs. 5-12; and

Fig. 14 perspective view of a third embodiment of a lining wear sensor according to the invention.

In Fig. 1-8 is a lining wear sensor 1 and a device for

Wear detection of a brake pad of a disc brake and its

Arrangement on or in a brake pad 2 shown.

The brake pad 2 has a lining carrier plate 3 with a plate plane E and an attached non-illustrated friction lining, which in the case of braking against a brake disc is pressed.

The lining wear sensor 1 has a contact conductor 20 and a

Fastening body 10 on. The fastening body 10 is u.a. in FIGS. 1 and 2,

but in particular in Fig. 1, shown in detail.

The pad wear sensor 1 comprises the T-shaped mounting body 10. This has a sensor head 9 with two stop legs 8 with stop surfaces 13 and a sensor foot 1 1, which is arranged in a recess 5 on the plate plane E. The stop surfaces 13 are in the assembled state of

Pad wear sensor 1 on the pad carrier plate 3, wherein the sensor head 9 projects beyond the lining carrier plate 3 and is arranged at the level of the friction lining.

The fastening body shown in Fig. 1 shows only a preferred variant of a mounting body. There are also many other variants feasible. Thus, the attachment body may be formed without stop leg or only with a stop leg.

Furthermore, at least one passage is provided in the sensor head 9, through which the contact conductor 20 can be guided. Specifically, Fig. 1 in the sensor head two

Bushings 12 are provided, wherein the contact conductor is guided as a conductor loop through both passages 12.

The contact conductor 20 may be formed as a cable. Upon contact of the brake disc with the contact conductor 20, there is a detection and generating a

Output signal. Thus, the distance corresponds to the implementation 12 and the

Inserted contact conductor 20 to the pad carrier plate 3 is slightly more than the minimum allowable thickness of the friction lining. If the contact conductor is damaged, a display is made to replace the friction lining, so that the truck soon has to go to the workshop to replace the brake pads.

The attachment body 10 is clamped in the recess 5 of

Pad carrier plate 3, wherein the pad carrier 3 in the recess 5 a pin. 7 having. The sensor foot 1 1 has an opening 6, in particular a bore, through which the pin 7 can be pushed through.

In an end region of the pin 7 may have a groove 14. Furthermore, the pin may have a circumferential projection 18, which between the

Pad carrier plate 3 and the mounting body can be arranged. Specifically, the pin 7 is set in a blind hole 19 edge in the lining carrier plate 3. The mounting body 10 can be secured against axial displacement on the pin 7 by a snap ring 15 which engages in the groove 14.

The diameter of the opening 6 in the sensor foot 1 1 is dimensioned larger than the diameter of the pin 7, so that a game or a tolerance range between the pin 7 and the mounting body 10 is provided. This tolerance range is bridged by a tolerance sleeve 16, also called tolerance ring, which as

Spring element is formed.

This spring element is shown in FIGS. 3 and 4.

In the tolerance sleeve 16 is preferably a slotted sheet metal sleeve, in the beads, preferably wave crests 17, are embossed.

As a material spring steel strip can be used. A corresponding spring band steel can be used for applications at temperatures of up to 220 ° C or more. He has up to this temperature constant spring properties. For

For brakes with higher temperature development Hastalloy spring steel band can be used.

The tolerance sleeve sits in the gap between the opening 6 and the pin 7. For the tight fit provide wave peaks 17, which are distributed over the entire circumference of the tolerance sleeve 16 and how many small compression springs act. By a certain excess of the tolerance sleeve 16, the wave crests 17 are elastically deformed, whereby a frictional connection between the sensor foot 1 1 and the pin 7 is formed. The attachment body 10 of the lining wear sensor 1 can advantageously be manufactured by an extrusion molding process.

The strand molding process is a forming process with which prismatic profiles can be manufactured. An example of a strand forming process is extrusion molding. Extrusion is counted according to DIN 8582 for pressure forming. In this case, a heated to forming temperature compact (block) is pressed with a punch through a die. In the process, the block is replaced by a recipient

enclosed. The outer shape of the pressed strand is determined by the die. Through differently shaped mandrels cavities can be generated. The

Extrusion is used to produce continuous material, which is separated in the desired length. The continuous material is then cut to length

Fastening body 10 isolated.

As a material, for example, a material composition can be used, which is known to those skilled in the art as Knetbeton.

In a second embodiment of a pad wear sensor 21, which is shown in FIGS. 5-11, the pad wear sensor 21 has a mounting body 30 also a sensor head 29 and a sensor foot 31.

In contrast to the vorhergrigen Ausührungsvariante of Fig. 1 -4, the

Sensor foot 31 a cylindrical shape.

The sensor head 29 is dimensioned wider than the sensor foot 31, so that the

Sensor head 29 at the transition between the sensor head 29 and the sensor foot 31 has a circumferential stop surface 33. This is as detailed in FIG. 13

represented, designed like a dental arch.

The plate spring 37 has, as clearly visible in FIG. 9, starting from a ring region 41, radially inwardly extending spring arms 42. These can be brought into engagement with the toothed ring-like abutment surface 33, so that an anti-rotation of the plate spring 37 is present. The lining wear sensor 21 also has, analogously to FIG. 1, a contact conductor 40. Furthermore, at least one passage is provided in the sensor head 29, through which the contact conductor can be guided. In the in Fig. 5-8 shown

Embodiment, the sensor head 29 on two bushings 32, wherein the contact conductor is guided as a conductor loop through both passages 32.

The sensor foot 31 defines a longitudinal axis 100, wherein the sensor foot 31 has a blind hole 36 parallel to the longitudinal axis 100.

Furthermore, part of the lining wear sensor 21 is a plate spring 37, which is arranged in the assembled state between the abutment surfaces 33 of the sensor head 29 and the lining carrier plate 23 and which is detachable from the mounting body 30. This is shown in detail in FIG. 9.

The lining carrier plate has an opening 39 perpendicular to the plate plane E, through which the lining wear sensor, in particular the sensor foot 31 of the

Fastening body 30, is guided.

The sensor foot 31 may have a groove 34 in a terminal area, as in FIG

Rear view of FIG. 12 recognizable, have. This groove 34, together with a snap ring 35, which can be assigned to the pad wear sensor 21 and which can be arranged detachably on the mounting body, the

Secure the fastening body against a drop of the fastening body 30 from the opening 39 of the lining carrier plate 23.

The mounting body 30 is thus resiliently mounted in the opening 39 of the lining carrier plate 23. The friction lining 24 is shown on the lining carrier plate 23 in FIG. 10 and also enlarged in FIG. 11.

At least the sensor head 9, 29, but preferably the entire attachment body 10 or 30 according to the invention of a cementitious material, in particular of a concrete material is formed. This may preferably be a fiber-reinforced cementitious material, as this significantly increases the tensile loads on the attachment body 10 or 30.

The sensor foot 1 1, 31 need not necessarily be made of the cementitious material, but it may, for example, in the embodiment of FIGS. 5-8 is a metal sleeve, which is encapsulated in the cementitious material.

The aforementioned fiber reinforcement is selected in particular from non-conductive fibers. The non-conductive fibers, in contrast to metal fibers, may preferably be glass fibers and / or polymer fibers. Aramid fibers are preferably formed as polymer fibers.

The fiber content of the cement-based material may advantageously be between 2 to 25% by volume.

By using the cement-based material, preferably the concrete material, for the part of the pad wear sensor 1 and 21 intended for abrasion, the material of the pad sensor is adapted in regions to the material of the friction pad. As a result, a reduction of the material costs of the polymer-based lining wear sensor used hitherto is also achieved. In addition, the use of the material allows a sufficient temperature stability against a Flitzeentwicklung caused due to a braking operation.

The fiber reinforcement also allows an amplification of the mechanical

Loading capacity and a further increase in the thermal stability of the lining wear sensor 1, 21 or at least individual concrete components, e.g. the respective sensor head 9, 29.

Both the tolerance sleeve 16 and the plate spring 37 serve as spring elements for mechanical compression when applying the brake. The friction material of the Friction pads typically a bit behind. In contrast, the sensor head is off

Concrete material rigid and would break.

FIG. 14 shows a further variant of a fastening body 51 of a

Pad wear sensor 50. This attachment body 51 can also be produced in an extrusion process. The fastening body 51 is dumbbell-shaped and comprises two terminal sensor heads 55, each with a

Feedthrough 56 for performing a contact conductor 57. Also in this variant, only a single implementation 56 may be provided in the attachment body.

Furthermore, the lining wear sensor 50 has two spring elements 52, which can be used in a lining carrier plate 53 of the brake lining. These are as

symmetrical U-shaped brackets formed with two spring legs 54, which are arranged between the lining carrier plate 53 and a sensor head 55. The spring legs lie in a spring region 58 on the sensor head 55 and are spaced in this area from the lining carrier plate 53. The mounting body 51 is thus resiliently mounted relative to the lining carrier plate 53.

By the aforementioned spring elements, an adaptation of the

Pad wear sensor to the elasticity of the friction lining material, so that the lining wear sensor does not prematurely trigger after a certain abrasion of the friction lining.

At the same time, the surface pressure by the friction lining material is intended to ensure reliable braking both during the locking process of a parking brake and during a normal braking operation.

Preferably, the material composition of the sensor head 9, 29 is selected so that it is subject to a higher wear rate than the friction material, so that no material bulges form in the region of the sensor head 9, 29 with increasing abrasion. Preferably, the cementitious material of the mounting body 10, 30 or

at least of the sensor head 9, 29 be formed as a UHPC material and particularly preferably a HRUHPC material. In particular, the latter material has a particularly favorable pressure and stability.

For optimum strength, the proportion of fibers in the cementitious material should be at least 1% by weight, preferably 2 to 12% by weight. Particularly preferred, since particularly heat-resistant, are glass fibers and / or carbon fibers.

The proportion of cement in the cementitious material may advantageously be at least 10% by weight, preferably at least 25% by weight.

The cementitious material may include at least one additive

Counteract shrinkage effects during drying. In this case, lime is particularly preferably formed as a water scavenger. Furthermore, various additives, especially in the form of oxides or carbides, can be added to the cementitious material to adjust the hardness.

LIST OF REFERENCE NUMBERS

1 pad wear sensor

2 brake pad

3 lining carrier plate

5 recess

6 opening

7 cones

8 stop legs

9 sensor head

10 mounting carcass

11 sensor foot

12 implementation

13 stop surfaces

14 groove

15 snap ring

16 tolerance sleeve

17 wave mountain

18 cantilever

19 blind hole

20 contact conductors

21 lining wear sensor

22 brake pad

23 lining carrier plate

24 friction lining

25 recess

29 sensor head

30 fixing body

31 sensor foot

32 implementation

33 stop surfaces

34 groove

35 snap ring 36 blind hole

37 plate spring

39 opening

40 contact conductors

41 ring area

42 spring arms

50 lining wear sensor

51 mounting body 52 spring elements

53 lining carrier plate

54 spring legs

55 sensor head

56 implementation

57 contact manager

58 spring range

100 longitudinal axis

E plate level

Claims

A lining wear sensor (1, 21) for mounting on or in a brake pad (2, 22) of a disc brake, comprising a mounting body (10, 30) and a contact conductor (20), the contact conductor (20) being connected to the mounting body (10, 10). 30), characterized in that the fastening body (10, 30) is at least partially formed of a cementitious material.

2. pad wear sensor according to claim 1, characterized in that

in particular, the abrasion-side region is designed as a sensor head (9, 29), in which the contact conductor (20) is guided, wherein the sensor head (9, 29) consists of the cementitious material.

3. pad wear sensor according to claim 1 or 2, characterized in that the fastening body (10, 30) resiliently to the brake pad (2, 22) can be arranged.

4. lining wear sensor according to one of the preceding claims, characterized in that the lining wear sensor (1, 21) has a spring element, for the resilient mounting of the mounting body (10, 30) on

Brake pad (2, 22).

5. pad wear sensor (1) according to claim 2, characterized in that the cementitious material is formed as a fiber-reinforced cementitious material.

6. lining wear sensor according to one of the preceding claims, characterized in that the cementitious material as a UHPC material, particularly preferably as a HRUHPC material, in particular as a fiber-reinforced HRUHPC material, is formed.

7. lining wear sensor according to any one of the preceding claims, characterized in that the proportion of fibers in the cementitious material at least 1 wt.%, Preferably 2 to 12 wt.%, Is.

8. lining wear sensor according to any one of the preceding claims, characterized in that the fibers of the fiber-reinforced cementitious material are glass fibers and / or carbon fibers.

9. lining wear sensor according to any one of the preceding claims, characterized in that the proportion of cement in the cementitious material at least 10 wt.%, Preferably at least 25 wt.% Is.

10. lining wear sensor according to one of the preceding claims, characterized in that the fastening body (10) in one

Strand molding process can be produced.

11. lining wear sensor according to one of the preceding Ansprüchem characterized in that the fastening body (10, 30) to a

Pad carrier plate (3, 23) of a brake lining (2, 22), in particular detachable, can be plugged or plugged.

12. Brake pad comprising a lining wear sensor (1, 21) according to one of the preceding claims.