Device for detecting wear of brake pads of a disc brake

Abstract

A device for identifying the wear of a brake pad of a disc brake, in particular a wear indicator device (10) for a vehicle brake (1), preferably a disc brake of a commercial vehicle, for indicating the wear of a brake pad (20), comprising: a fixing section (12) for fixing the wear indicator device (10) to a brake pad back plate (30); a sensor head (14) associated with the fixing section (12); and a channel (16) for receiving a signal cable (40) in the sensor head (14). According to the invention, the channel (16) is configured to receive two signal cables (40', 40").

Description

Technical Field

[0001] The invention relates to a wear indicator device for a vehicle brake, preferably a disc brake of a commercial vehicle, for indicating the wear of a brake pad, the indicator device comprising a fixing section for fixing the wear indicator device to a brake pad back plate, a sensor head associated with the fixing section, and a channel for receiving a signal cable in the sensor head.

[0002] The invention further relates to a vehicle brake, preferably a disc brake of a commercial vehicle, comprising a brake pad backing plate for carrying a brake pad. Background Art

[0003] Disc brakes for vehicles are well known. To generate braking force, a brake shoe, which includes a brake pad backing plate and a brake pad, is pressed against a brake disc. This causes the brake pad to wear over time.

[0004] As is known, electrical contact conductors, such as cables, can be arranged in brake pads to monitor the thickness of the brake pads, in particular to determine whether the brake pads have fallen below an allowed wear limit. The brake pads have cutouts for arranging sensor heads within the brake pads. When the wear limit is reached, the contact conductors come into contact with the brake disc during braking and are worn away. This causes an electrical signal to be sent to a signal transmitter and a warning signal is generated.

[0005] Such a device is described, for example, in DE 10 2010 048 988 A1. Here, two channels are arranged in the sensor head to receive the U-shaped, in particular the contact ring, of the signal cable. However, a disadvantage of this arrangement is that the sensor head is susceptible to damage. Summary of the invention

[0006] It is therefore an object of the present invention to provide a wear indication device which overcomes at least some of the above mentioned problems. In particular, it is an object of the present invention to provide a wear indication device which is structurally simple in design and at the same time robust and resistant to damage.

[0007] According to the invention it is proposed that the channel is configured to receive two signal cables. According to the invention the term two cables is also to be understood as two cable sections of a single cable, for example in the case of a U-shaped contact ring of a cable.

[0008] According to a preferred embodiment, the channel is a double channel having a first section for a first cable and a second section for a second cable, wherein the first section and the second section are adjacent to each other in a radial direction relative to their central axis. The radial direction is a direction orthogonal to the central axis. The first section and the second section of the channel are used to arrange the two cables together in the channel, but at least partially separated from each other, so that each cable is allocated in a separate section.

[0009] Preferably, the distance between the center axis of the first signal cable and the fixed section is greater than the distance between the center axis of the second signal cable and the fixed section. If both cables (sections) are at the same distance from the fixed section, i.e. their center axes are arranged in a plane parallel to the brake disc plane during installation, then both cables (sections) are worn together and will be worn out together after reaching the wear limit. In this case, it may happen that both cables release the fixed contact at the same time and are damaged by the brake disc or do not come into contact with the brake disc at all. This will lead to error messages and the diagnosis function cannot be performed.

[0010] Preferably, the respective cross sections of the first section and the second section overlap at least partially, so that the channel has a narrow necking area which partially separates the first section from the second section by means of at least one protrusion, preferably two opposite protrusions, in the sensor head protruding inwards into the double channel. In this way, the two cables can be positioned as close to each other as possible on the one hand and separately from each other in different sections on the other hand. The task of the sensor is to emit a signal as soon as one of the cables, preferably the upper cable or the cable with the smallest axial distance to the brake disc when installed, is exposed and in contact with the brake disc. This is the case when the sensor head is ground flat, thereby exposing the first section of the double channel. By means of the protrusions, the second cable can be kept in the second section without sliding out of its position in the second section when the first section is exposed. The term axial refers to the axial direction or axial axis of the wear indication device. It is defined as an axis orthogonal to the zero plane, wherein the zero plane represents the contact surface between the brake pad back plate and the wear indication device when installed, and wherein the zero plane is a plane parallel to the brake disc. This definition applies unless otherwise defined below.

[0011] According to a further embodiment, the first section and / or the second section of the dual channel at least partially has a circular cross section. The inner contour of the channel should match the outer contour of the cable. In particular, the inner contour of the first section should have a contour corresponding to the outer contour of the cross-sectional area of ​​the first cable, and the inner contour of the second section should have a contour corresponding to the outer contour of the cross-sectional area of ​​the second cable.

[0012] According to a further preferred embodiment, the geometry of the dual channel is such that the two signal cables are arranged at least partially parallel to each other in the channel, in direct contact or at a distance from each other. An important requirement when arranging the cables in the sensor head is to keep the axial distance as small as possible.

[0013] Preferably, the wear indication device further comprises a substantially flat contact surface for contacting the brake pad back plate when the wear indication device is installed, the contact surface defining a zero plane having an axial axis orthogonal to the plane. The sensor device of the present invention determines the wear limit of the brake pad. The wear limit is defined by a plane substantially parallel to the zero plane. An indicator that the wear limit has been reached is the contact between the brake disc and one of the cables. For this reason, a precise arrangement of the sensor device is desirable in order to achieve representative output values. Due to the partial incomplete plane-parallel removal of the brake pad, at least partial routing of the cable within the wear limit plane is justified. It should be understood that the cable routing described in this section also defines a cable section within the sensor head which is axially farthest from the zero plane and is therefore axially closest to the brake disc when installed.

[0014] According to a preferred embodiment, the geometry of the channel is such that the two signal cables are arranged in the channel perpendicular to the axial axis. Preferably, the distance from the center axis of the first signal cable to the zero plane in the direction of the axial axis is greater than the distance between the center axis of the second signal cable and the zero plane. Preferably, the center axes of the first signal cable and the second signal cable define a plane perpendicular to the zero plane. This is for the same reasons as mentioned in the previous (one or more) paragraphs, namely to keep the axial space required for the cables as small as possible while ensuring the longest possible wiring in the wear limit plane and keeping at least one cable section in the channel when the other cable has worn out. In another embodiment, the dual channel can be arranged so that the center axes of the first signal cable and the second signal cable define a plane arranged at an angle of less than 90° to the zero plane. Preferably, as described in this paragraph, the center axes of the first cable and the second cable extend at least partially parallel to the zero plane or perpendicular to the axial axis.

[0015] Preferably, the channel and the signal cable extend at least partially parallel to the zero plane. This is for the same reasons as described in the previous paragraphs. In addition, parallel wiring has a positive effect on minimizing the space required for the channel in the axial direction.

[0016] According to a further embodiment, the channel has a geometry such that the two signal cables are in contact so that they have the smallest possible distance from each other within the channel. As described in the previous paragraph, it is important to use as little space as possible in the axial direction, since this also minimizes the axial distance between the wear limit and the zero plane. Thus, the amount of brake pad removal can be maximized until the wear limit is reached, which is defined by the position of the cable (segment) that is axially farthest from the zero plane.

[0017] Preferably, the sensor head consists essentially of plastic material. The wear indicating device is exposed to extreme temperatures during operation. Therefore, the material (eg plastic) used for this purpose must be of high quality.

[0018] In a second aspect, the object of the invention is solved by a vehicle brake, preferably a disc brake of a commercial vehicle, comprising a wear indication device configured according to one of the preferred embodiments described above.

[0019] It will be appreciated that the preferred embodiments and advantages of the wear indication device are at the same time preferred embodiments and advantages of the vehicle brake according to the second aspect. To avoid repetitions, reference is made to the above description.

[0020] Preferably, the channel is arranged inside the brake pad outside the brake pad back plate. In the present embodiment, the wear indicating device has a sensor head and a fixing section. When mounted, the fixing section is located inside the brake pad back plate and the sensor head is located in a cutout of the brake pad. This allows to simplify the structural design of the wear indicating device. In particular, if the channel is formed completely inside the sensor head, i.e. inside the brake pad, the connection mechanism for coupling the wear indicating device to the brake pad back plate can become simpler and more robust. The connection mechanism of the wear indicating device to the brake pad back plate should be as permanently stable as possible so that the positioning of the cable is reliable and constant. Any position change is undesirable because it affects the safety signal. For example, it may cause the above-mentioned warning to be given too early or too late.

[0021] According to a preferred embodiment, the end of the channel closest to the brake pad back plate is located at a distance of 1 mm or less from the brake pad back plate. As already mentioned, the axial distance of the cable and therefore of the channel to the zero plane must be kept as small as possible in order to be able to set the lowest possible wear limit in the axial direction, i.e. keep the distance of the wear limit to the zero plane as low as possible. This has the advantage of maximizing the utilization of the brake pad.

[0022] According to a preferred embodiment, the vehicle brake further comprises a brake pad, wherein the wear indicating device, in particular the sensor head, is at least partially arranged in a cutout in the brake pad. This is necessary at least for one reason, namely that the at least one cable must be at least partially arranged within the wear limit of the brake pad.

[0023] The disclosed aspects can be best understood from the following detailed description in conjunction with the accompanying drawings. For clarity, the figures are schematic and simplified, and only show details that improve the understanding of the claims while omitting other details. Throughout, the same reference numerals are used for identical or corresponding parts. The individual features of each aspect can be combined with any or all features of other aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] These and other aspects, features and / or technical effects will become apparent and elucidated by reference to the drawings described below, which are as follows:

[0025] Figure 1 : A top view of a preferred embodiment of a wear indication device according to the present invention;

[0026] Figure 2 : A perspective view of a vehicle brake including a preferred embodiment of a wear indication device according to the present invention;

[0027] Figure 3 : A top view of an alternative embodiment of a wear indication device according to the concepts of the present invention;

[0028] Figure 4 :according to Figure 3 A perspective view of a wear indicator device of FIG. 1 ; and

[0029] Figure 5 , Figure 6 : Top view of a prior art solution for a wear indicating device. DETAILED DESCRIPTION

[0030] Figure 1 The wear indicator device 10 in a preferred embodiment of a vehicle brake 1 is shown. The wear indicator device 10 comprises a fixing section 12 (not shown / visible) which is located within the brake pad backing plate 30 when the wear indicator device 10 is installed, so see Figure 6 The exemplary fixing section in FIG. 1 is used as a fixing section according to the prior art. The fixing section 12 is used to fix the wear indication device 10 to the brake pad backing plate 30. To this end, the fixing section 12 can adopt any suitable shape.

[0031] The wear indication device 10 further comprises a sensor head 14 and a passage 16 for receiving a signal cable 40 within the sensor head 14. According to the present invention, the passage 16 is configured to receive two signal cables 40', 40" (not shown), so see Figure 4 Example cable routing in .

[0032] The channel 16 of the wear indication device 10 is a double channel with a first section 102 for the first cable 40' and a second section 104 for the second cable, or with a first section 102 and a second section 104 for the first cable section 40' and the second cable section 40" for the signal cable, respectively. Figure 4 Best shown.

[0033] exist Figure 1 In the top view of , it can be seen that the first section 102 of the channel 16 has a greater distance from the fixing section 12 in the direction of the axis A than the second section 104 of the channel 16, that is, in the installed state, has a greater distance from the zero plane Z or the brake pad back plate 30.

[0034] The double channel also has two opposing protrusions 108. These are arranged to retain the respective cable section 40', 40" in the respective designated section 102, 104 of the channel 16. This is particularly useful if the cable channel 16 has been worn by the brake disc and is therefore partially exposed.

[0035] In addition, the cross section of each section 102, 104 of the channel 16 is designed to be substantially circular so as to surround the circular cross section of the signal cable 40. Because the signal cables 40 in the channel 16 can contact each other, the corresponding sections 102, 104 of the channel 16 at least partially overlap. Therefore, the channel 16 has a narrow necking area 106 that partially separates the first section 102 from the second section 104 by means of at least one protrusion 108.

[0036] The wear indication device 10 further comprises a substantially flat contact surface for contacting the brake pad backing plate 30 when the wear indication device 10 is mounted, said contact surface defining a zero plane Z. The contact surface is located on the back side of the sensor head 14, so that when the wear indication device 10 is mounted, the sensor head 14 is in contact with the zero plane Z or the brake pad backing plate 30. Thus, the zero plane Z also separates the sensor head 14 from the fixing section 12 of the wear indication device 10.

[0037] The cables 40 extend substantially parallel to one another within the channel 16 , or the cable sections 40 of the U-shaped contact ring extend parallel to one another, so that they also extend parallel to the zero plane Z.

[0038] exist Figure 1 In a preferred embodiment of the invention, the sections 102, 104 of the channel 16 are arranged one above the other in the axial direction A, so that when the first and second signal cables 40', 40" are arranged in the double channel, the central axes of the first and second signal cables 40', 40" define a plane perpendicular to the zero plane (Z). In an alternative embodiment, see, for example Figure 3 and Figure 4, the sections 102, 104 of the channel 16 are offset relative to the axial axis A. In this case, when the first and second signal cables 40', 40" are arranged in a double channel, the central axes of the first and second signal cables 40', 40" define a plane that is less than 90° from the zero plane (Z). Figure 1 , Figure 3 and Figure 4 As can be seen in FIG. 1 , the cable (section) 40 within the sensor head 14 extends parallel to the zero plane Z and perpendicular to the axial axis A.

[0039] The cables (sections) 40 are adjacent to one another in the channel 16 , so that the dimensions of the channel 16 can be selected to be correspondingly small.

[0040] Figure 2 The disc brake 1 is shown to include a brake bracket 70 which can be mounted to a corresponding receiving section of a vehicle. The disc brake 1 also includes a brake caliper 60 which forms a receiving space for, in particular, a brake pad backing plate 30 which is configured to carry a brake pad 20 having a friction lining (not shown) which is in contact with the disc of the brake during braking in order to apply a braking force.

[0041] Furthermore, the brake pad backing plate 30 has a wear indicating device 10 configured to assess the degree of wear of the brake pad 20. The wear indicating device 10 is coupled to the brake pad backing plate 30 and is at least partially received in a recess (not shown) thereof.

[0042] The wear indication device 10 is coupled to a signal cable 40 having a connector on its distal end. When the wear indication device 10 is installed, the cable sections 40', 40" of the signal cable 40 pass through the channel 16 in the sensor head 14 of the wear indication device 10 in a U-shaped contact loop. Thus, the entire cable channel 16 is located at the height of the brake pad 20, such as Figure 4 Best shown.

[0043] The distance from the lower end of the channel 16 , in particular the lower end of the second section 104 , to the zero plane Z is preferably 1 mm or less.

[0044] The brake pad 20 has a cutout 110 around the recess (see Figure 4 ), so that the recess is arranged in the region of the cutout 110. Thus, the wear indication device 10 is surrounded by the brake pad 20, wherein the cutout 110 allows easy access to the wear indication device 10.

[0045] The brake pad backing plate 30 carrying the brake pad 20 is held in place by a spring hanger 50. The spring hanger 50 is preferably connected to the brake caliper 60 by a spring hanger seat 54 on one side and by a spring hanger fixture 52 on the other side. After releasing the spring hanger fixture 52 and guiding the spring hanger 50 out of its seat 54, the spring hanger 50 can be removed. When the spring hanger 50 is removed, the brake pad 20 together with the brake pad backing plate 30 can also be removed and replaced.

[0046] Figure 5 and Figure 6 Here, the signal cable (section) 40 is routed along two separate channels 16', 16" within the sensor head 14, as shown in FIG. Figure 5 As shown, the first channel 16' is arranged in the sensor head 14, and the second channel 16" is arranged in the fixing section 12, as shown in FIG. Figure 6 shown.

[0047] Reference numerals list

[0048] 1Vehicle brakes

[0049] 10 Wear indicator

[0050] 12 fixed sections

[0051] 14Sensor head

[0052] 16 channels (16', 16")

[0053] 20 brake pads

[0054] 30 Brake pad backing plate

[0055] 40 Signal Cable (40', 40")

[0056] 50 Spring hanger

[0057] 52 hanger fixing device

[0058] 54 hanger seat

[0059] 60 brake caliper

[0060] 70 brake bracket

[0061] 102 Part 1

[0062] 104 Part 2

[0063] 106 Narrow neck area

[0064] 108 protrusions

[0065] 110 incision

[0066] A Axial direction

[0067] Z Zero Plane

Claims

1. A wear indicator device (10) for a vehicle brake (1), for indicating the wear condition of a brake pad (20), the wear indicator device (10) comprising: a fixing section (12) for fixing the wear indication device (10) to a brake pad back plate (30), a sensor head (14) associated with the fixing section (12), and a passage (16) for receiving a signal cable (40) within the sensor head (14), Characterized in that the one channel (16) is constructed to receive two signal cables (40', 40"), wherein the one channel extends completely through the sensor head in a direction parallel to the two signal cables; wherein the one channel (16) is a double channel, the double channel having a first section (102) for a first cable (40') and a second section (104) for a second cable (40"), wherein the first section (102) and the second section (104) are radially positioned adjacent to each other relative to their center axes; and wherein a distance from a center axis of the first section for the first signal cable (40') to the fixed section (12) is greater than a distance between a center axis of the second section for the second signal cable (40") and the fixed section (12).

2. The wear indicating device (10) according to claim 1, It is characterized in that The respective cross sections of the first section (102) and the second section (104) at least partially overlap, so that the one channel (16) has a narrow necking region (106), which partially separates the first section (102) from the second section (104) by means of at least one protrusion (108) in the sensor head (14) protruding inwardly into the dual channel.

3. The wear indication device (10) according to claim 1 or 2, It is characterized in that The first section (102) and / or the second section (104) of the dual channel at least partially has a circular cross section.

4. The wear indication device (10) according to claim 1 or 2, It is characterized in that The geometry of the dual channel is such that the two signal cables (40', 40") are arranged at least partially parallel to each other in the one channel (16), in direct contact or at a distance from each other.

5. The wear indicating device (10) according to claim 1 or 2, It is characterized in that The wear indicator device (10) further comprises a substantially planar contact surface for contacting a brake pad backing plate (30) when the wear indicator device (10) is installed, the contact surface defining a zero plane (Z) having an axial axis (A) orthogonal to the zero plane.

6. The wear indicating device (10) according to claim 5, It is characterized in that The geometry of the one channel (16) is such that the two signal cables (40', 40") are arranged perpendicular to the axial axis (A) within the one channel (16).

7. The wear indication device (10) according to claim 5, It is characterized in that The distance between the center axis of the first signal cable (40') and the zero plane (Z) in the direction of the axial axis (A) is greater than the distance between the center axis of the second signal cable (40") and the zero plane (Z).

8. The wear indicating device (10) according to claim 5, It is characterized in that The central axes of the first signal cable (40') and the second signal cable (40") define a plane perpendicular to the zero plane (Z).

9. The wear indicating device (10) according to claim 5, in, The one channel (16) and the two signal cables (40', 40") extend at least partially parallel to the zero plane (Z).

10. The wear indicating device (10) according to claim 1 or 2, It is characterized in that The geometry of the one channel (16) enables the two signal cables (40', 40") to be in contact, so that the two signal cables (40', 40") have the minimum possible distance from each other within the one channel (16).

11. The wear indicating device (10) according to claim 1 or 2, It is characterized in that The sensor head (14) consists essentially of plastic material.

12. The wear indicating device (10) according to claim 1, It is characterized in that The wear indicating device is a wear indicating device for a disc brake of a commercial vehicle.

13. The wear indication device (10) according to claim 2, It is characterized in that The at least one protrusion (108) is two opposing protrusions (108).

14. A vehicle brake (1), comprising: a brake pad back plate (30), wherein the brake pad back plate (30) is used to carry the brake pad (20), Characterized in that the vehicle brake (1) further comprises: A wear indicating device (10) according to any one of the preceding claims, for indicating the wear of the brake pad (20).

15. The vehicle brake (1) according to claim 14, It is characterized in that The one channel (16) is disposed within the brake pad (20) exteriorly of the brake pad back plate (30).

16. Vehicle brake (1) according to claim 14 or 15, It is characterized in that The distance between the end of the channel (16) closest to the brake pad back plate (30) and the brake pad back plate (30) is 1 mm or less.

17. Vehicle brake (1) according to claim 14 or 15, It is characterized in that The vehicle brake (1) further comprises the brake pad (20), wherein the wear indicating device (10) is at least partially arranged in a cutout (110) in the brake pad (20).

18. The vehicle brake (1) according to claim 14, It is characterized in that The vehicle brake (1) is a disc brake for a commercial vehicle.

19. Vehicle brake (1) according to claim 14 or 15, It is characterized in that The vehicle brake (1) further comprises the brake pad (20), wherein the sensor head (14) is at least partially arranged in a cutout (110) in the brake pad (20).

Images