Brake device and method for determining a distance parameter between a first brake component and a second brake component of a brake device

Abstract

The invention relates to a brake device with at least one first brake component (10a-c) and at least one second brake component (12a-c), which are provided to cooperate to provide a braking torque and are arranged contactlessly and movably relative to each other in an unactuated state, and with a sensor unit (14a-c), which is provided to determine a distance parameter between the first brake component (10a-c) and the second brake component (12a-c). It is proposed that the sensor unit (14a-c) is designed to determine the distance parameter independently of brake actuation and comprises at least one non-contact measuring sensor element (16a-c) arranged on and / or integrated into the first brake component (10a-c) and evaluation electronics (18a-c) that interact with the sensor element (16a-c).

Description

State of the art

[0001] The invention relates to a brake device according to the preamble of claim 1 and to a method for determining a distance parameter between a first brake component and a second brake component of a brake device. Furthermore, the invention relates to a wheel brake with such a brake device and to a vehicle with such a wheel brake.

[0002] Various methods for determining a distance parameter, in particular a brake clearance, between two brake components of a brake system are known from the prior art. For example, DE 101 38 452 A1 describes a method for adjusting a brake clearance in a disc brake, in which the current brake clearance is determined by sensor means that are not part of the adjusting device, and in which the determination of the brake clearance requires brake actuation by the driver and / or a blind brake actuation.

[0003] Furthermore, various methods for determining the wear state of a brake component of a braking system are known. For example, there are special brake pad wear sensors that issue a warning when the brake pad is excessively worn. Most are based on measuring the resistance of a sensor wire that wears down along with the brake pad during operation. Depending on the degree of wear of the brake pads, the sensor wire also wears down or is severed at a certain point, so that the wear state can be determined based on a change in resistance. However, DE 102 11 813 A1 also discloses a method for checking the functional reliability of brake components, in particular of wear and / or functional parts of a disc brake that change their position, in which ultrasonic sensors are used to determine the wear state of the brake pad and / or the brake disc.Furthermore, in this case, a clearance can also be determined based on a change in the position of a bridge and a clamping device.

[0004] The current state of the art has in common that active braking is always required to determine the distance parameter or air clearance. However, a continuous and / or brake-independent determination of the distance parameter or air clearance is not possible using the brake devices or methods known from the prior art.

[0005] The object of the invention is, in particular, to provide a brake device and a method for determining a distance parameter between two brake components of a brake device with improved distance detection properties. This object is achieved by the features of claims 1, 13, 14, and 15, while advantageous embodiments and further developments of the invention can be found in the dependent claims. Disclosure of the invention

[0006] The invention relates to a brake device with at least one first brake component and at least one second brake component, which are designed to work together to provide a braking torque and are arranged in an unactuated state without contact and are movably mounted relative to each other, and with a sensor unit, which is designed to determine a distance parameter between the first brake component and the second brake component.

[0007] It is proposed that the sensor unit be designed to determine the distance parameter independently of brake application or actuation of the brake device, and comprise at least one non-contact measuring sensor element arranged, in particular attached, to and / or integrated into the first brake component, as well as evaluation electronics that interact with the sensor element. This design can, in particular, improve distance detection, enabling advantageously continuous and / or brake-independent determination of the distance parameter. Furthermore, advantageously efficient and / or flexible determination of the distance parameter can be achieved.

[0008] The term "brake device" refers to at least a part, in particular a subassembly, of a brake, especially a friction brake. Preferably, the brake device or brake is intended for use in a vehicle, more preferably a motor vehicle, and is therefore advantageously designed as a wheel brake, particularly advantageously in the form of an electromechanical parking brake and / or an electromechanical service brake. Preferably, the vehicle further comprises several brake devices, such as two or four brake devices, with one brake device assigned to each wheel of the vehicle. The term "brake component" refers in particular to a component and / or assembly that is used and / or required for a braking process and is specifically designed to interact with at least one other brake component to provide braking functionality.In particular, the first and second brake components are arranged in a contactless and / or separate manner in the unactuated state and are movably mounted relative to each other. In an actuated state, they form at least one contact point and / or contact surface to provide the braking torque. Thus, the first and second brake components are not permanently in contact with each other, but can be moved relative to each other during brake actuation or actuation of the brake device in such a way that they touch or are in contact with each other. The first and second brake components could, for example, be part of a drum brake and be designed as a brake shoe and a brake ring, respectively. Preferably, however, the first and second brake components are part of a disc brake and are designed as a brake pad and a brake disc, respectively.The brake component designed as a brake pad can, in particular, comprise at least one support element, especially a pad carrier, and a brake pad coupled to the support element. It is particularly preferred that the first brake component, on which the sensor element is arranged and / or in which the sensor element is integrated, is designed as a brake pad, while the second brake component is designed as a brake disc. Furthermore, a "distance parameter" is understood to mean, in particular, a parameter that correlates with a distance, especially an air gap, between the first brake component and the second brake component.In particular, at least on the basis of the distance parameter, it is possible to infer and / or determine an actual and / or minimum distance between the first brake component and the second brake component, especially in the unactuated state. In principle, the distance parameter can also correspond directly to the actual and / or minimum distance between the first brake component and the second brake component, especially in the unactuated state. In the present case, the distance parameter to be determined is particularly preferably a clearance.Furthermore, the term "sensor unit" shall be understood to mean, in particular, a detection unit operatively connected to the first and second brake components, which is designed to determine the distance parameter and, in particular, to detect the distance parameter and / or a detection signal correlated with the distance parameter without contact. For this purpose, the sensor unit comprises, in particular, at least one sensor element, preferably in the form of a sensor head, which measures without contact, and the evaluation electronics arranged at a distance from the sensor element and cooperating with the sensor element. The evaluation electronics are preferably electrically connected to the sensor element and arranged in a protected area spaced apart from the sensor element, as well as from the first and second brake components.Preferably, the evaluation electronics are also designed to continuously determine the distance parameter. "Designed" is understood to mean specifically programmed, designed, and / or equipped. The fact that an object is designed for a specific function is understood to mean, in particular, that the object fulfills and / or performs this specific function in at least one application and / or operating state.

[0009] According to one embodiment of the invention, it is proposed that the sensor element be configured as a sound sensor, in particular an ultrasonic sensor, or as a radar sensor. In this case, the sensor element is preferably configured as a combined transmitter and receiver unit and is designed to emit a transmit signal, preferably pulsed, to detect the distance parameter and to receive at least one reflection signal and / or echo signal correlated with the transmit signal, preferably pulsed. Furthermore, the evaluation electronics are advantageously designed to evaluate at least one of the received reflection signals and / or echo signals to determine the distance parameter. This allows, in particular, the provision of an advantageously efficient, non-contact measuring sensor element.

[0010] In this context, it is further proposed that the first brake component comprises at least one support element, in particular a pad carrier, and that the sensor element is arranged on the support element, in particular attached to it, and / or integrated into the support element. In particular, the sensor element can be arranged in a central area of ​​the support element and / or integrated into the central area of ​​the support element. Alternatively, the sensor element can also be arranged in an edge area of ​​the support element, for example, on a frame of the first brake component and / or the support element. It is particularly advantageous that the sensor element is connected to the support element via an acoustic coupling agent, in particular a coupling oil, a coupling gel, and / or a coupling paste. This allows for a particularly robust and effective coupling of the sensor element to the first brake component.

[0011] Furthermore, it is proposed that the sensor element is designed as a combined transmitter and receiver unit and is intended to transmit a transmission signal and to receive at least one reflection signal correlated with the transmission signal, wherein the evaluation electronics are intended to determine the distance parameter based on a correlation between the transmission signal and the reflection signal and / or based on a correlation of several reflection signals.In this case, the evaluation electronics are specifically designed to determine the distance parameter based on a time difference between the transmission of the transmit signal and the reception of the reflection signal, in particular a first reflection signal immediately following the transmit signal, which is correlated with the transmit signal, or based on a time difference between a first reflection signal, in particular a correlated with the transmit signal and immediately following the transmit signal, and a second reflection signal, in particular a correlated with the transmit signal and immediately following the first reflection signal.If the first brake component is designed as a brake pad, the evaluation electronics are specifically designed to determine the distance parameter based on the time-of-flight difference between a first reflection signal, correlated with the transmitted signal and generated at a first interface between a surface of the brake pad and air, and a second reflection signal, correlated with the transmitted signal and generated at a second interface between air and the brake disc. This allows the distance parameter to be determined in a particularly simple and efficient manner.

[0012] Furthermore, it is proposed that the evaluation electronics be designed, in particular additionally, to determine brake pad thickness based on a correlation between the transmitted signal and the reflected signal and / or based on a correlation of several reflected signals. Specifically, in this case, the evaluation electronics are designed to determine the brake pad thickness based on a time difference between the transmission of the transmitted signal and the reception of the reflected signal, in particular a first reflected signal that immediately follows the transmitted signal, or based on a time difference between a first reflected signal, in particular a correlation with the transmitted signal and immediately following the transmitted signal, and a second reflected signal, in particular a correlation with the transmitted signal and immediately following the first reflected signal.If the first brake component is designed as a brake pad, the evaluation electronics are specifically designed to determine the brake pad thickness based on the time difference between the transmission of the transmit signal and the reception of the first reflection signal immediately following the transmit signal. This allows for particularly high efficiency, as both the distance parameter and the actual brake pad thickness can be determined.

[0013] According to an alternative embodiment of the invention, it is proposed that the sensor element be designed as a capacitive sensor. In this case, the sensor element preferably has at least one measuring electrode and is designed to interact with the second brake component to detect the distance parameter and to detect an electrical capacitance, particularly with respect to the second brake component. In this case, the sensor element is advantageously controlled by alternating current. Furthermore, the evaluation electronics are advantageously designed to evaluate the capacitance measured by the sensor element in order to determine the distance parameter. This allows, in particular, the provision of a robust, non-contact measuring sensor element.

[0014] Furthermore, it is proposed that the sensor element be arranged and / or integrated into the first brake component such that the sensor element and the second brake component come into contact when the brakes are applied, and that the sensor element be designed to wear down uniformly along with the first brake component during operation. Accordingly, the sensor element is made of a suitable material that does not damage the second brake component, withstands high temperatures, and does not wear unevenly. In particular, the sensor element can be arranged in a central area of ​​a support element of the first brake component and / or integrated into the central area of ​​the support element. Alternatively, the sensor element can also be arranged in an edge area of ​​the support element, for example, on a frame of the brake pad.This allows for a particularly advantageous and robust coupling of the sensor element with the first brake component.

[0015] Furthermore, it is proposed that the sensor element comprises a measuring electrode whose diameter is larger than the maximum distance between the first brake component and the second brake component, particularly even when the first brake component and / or the second brake component are worn. In particular, the sensor element and / or the measuring electrode can be cylindrical, preferably circular, with the diameter of a cover surface, especially one facing the second brake component, defining the diameter of the measuring electrode. This allows for particularly precise measurement of the distance parameter.

[0016] Further improvement in measurement accuracy, and in particular a homogenization of the field lines of the measuring electrode, can be achieved if the sensor element comprises a shielding electrode surrounding the measuring electrode and a separating element arranged between the measuring electrode and the shielding electrode. The shielding electrode and the separating element are preferably designed as hollow cylinders and arranged concentrically around the measuring electrode.

[0017] Furthermore, a method for determining a distance parameter between a first brake component and a second brake component of a brake device, in particular the brake device mentioned above, is proposed, wherein the distance parameter is determined independently of brake actuation or actuation of the brake device, and at least one non-contact measuring sensor element arranged on and / or integrated into the first brake component is used to detect the distance parameter. This allows, in particular, the advantages already mentioned above to be achieved.

[0018] The braking device and the method for determining the distance parameter are not limited to the application and embodiment described above. In particular, the braking device and the method for determining the distance parameter may, to achieve the functionality described herein, comprise a different number of individual elements, components, and units than specified herein. Drawings

[0019] Further advantages become apparent from the following description of the drawings. The drawings illustrate three exemplary embodiments of the invention.

[0020] They show: Fig. 1 a vehicle with several vehicle wheels and with a braking system comprising several wheel brakes, each with a braking device, in a simplified representation, Fig. 2 Two brake components and a sensor unit of a brake device in a detailed view, Fig. 3. An exemplary diagram of various signals for determining a distance parameter between the brake components. Fig. 4 another embodiment of a brake device with an alternative sensor unit, and Fig. 5a-b is another embodiment of a brake device with an alternative sensor unit. Description of the exemplary implementations

[0021] Fig. Figure 1 shows a schematic representation of an exemplary vehicle 38a designed as a motor vehicle, with several vehicle wheels 40a and a braking system 42a comprising several wheel brakes 36a. In this example, each vehicle wheel 40a is assigned one of the wheel brakes 36a. The wheel brakes 36a are designed as friction brakes, in this example as electromechanical service brakes. The wheel brakes 36a are also designed as disc brakes. The wheel brakes 36a are identical in construction, so the following description is essentially limited to one of the wheel brakes 36a. In principle, a vehicle could also be designed as a two-wheeler or three-wheeler. Furthermore, a vehicle could be designed as a commercial vehicle. It is also conceivable to design a braking system as a conventional hydraulic and / or pneumatic braking system. In addition, a wheel brake according to the invention could also be designed as a drum brake.

[0022] Fig. Figure 2 shows one of the wheel brakes 36a in a more detailed representation. The wheel brake 36a has a brake assembly. The brake assembly comprises a first brake component 10a. The first brake component 10a is designed as a brake pad and includes a support element 20a, in particular a lining carrier, as well as a brake lining 44a coupled to the support element 20a. The brake assembly further comprises a second brake component 12a. The second brake component 12a is designed as a brake disc. The two brake components 10a, 12a are designed as friction partners and are intended to interact to provide a braking torque. In the unactuated state of the wheel brake 36a, the brake components 10a, 12a are arranged without contact and / or separately from each other and are movably mounted relative to each other.In particular, the brake components 10a, 12a are therefore not permanently in contact with each other, but can, especially when the brake is applied or when the wheel brake 36a is applied, for example by a driver of the vehicle 38a, be moved relative to each other in such a way that they touch and thereby form a contact point and / or contact surface.

[0023] Furthermore, the brake device includes a sensor unit 14a. The sensor unit 14a has an operative connection with the brake components 10a and 12a and is designed, at least, to determine a distance parameter, in this case, in particular, a clearance, between the first brake component 10a and the second brake component 12a. In this case, the sensor unit 14a is designed to determine the distance parameter independently of brake actuation or actuation of the wheel brake 36a. For this purpose, the sensor unit 14a includes a sensor element 16a and evaluation electronics 18a that interact with the sensor element 16a.

[0024] The sensor element 16a is designed to detect the distance parameter or a detection signal correlated with the distance parameter. The sensor element 16a is configured as a non-contact measuring sensor or sensor head. In this case, the sensor element 16a is configured as an ultrasonic sensor, specifically as a combined transmitter and receiver unit. In principle, however, a sensor element could also be configured as a sound sensor other than an ultrasonic sensor, for example, as an infrasound sensor, or as a radar sensor. Furthermore, it is conceivable to design a transmitter unit and a receiver unit of a sensor element separately. In addition, the sensor element 16a is arranged on the first brake component 10a and, in particular, integrated into the support element 20a.In the present case, the sensor element 16a is arranged in an edge region of the carrier element 20a, specifically such that the sensor element 16a does not protrude into the brake pad 44a or any part thereof. Alternatively, the sensor element 16a could also be arranged or attached in a central region of the carrier element 20a and / or to a frame of the first brake component 10a. Furthermore, it is also conceivable to arrange a corresponding sensor element on a brake component designed as a brake disc. In addition, the sensor element 16a is connected to the carrier element 20a via an acoustic coupling medium 22a, for example, a coupling oil and / or a coupling paste, to achieve good acoustic coupling.

[0025] The evaluation electronics 18a are designed to determine the distance parameter based on at least one detection signal from the sensor element 16a. In this case, the evaluation electronics 18a are designed to continuously determine the distance parameter. The evaluation electronics 18a are electrically connected to the sensor element 16a, in particular via an electrical connecting element 46a. Furthermore, the evaluation electronics 18a are electrically connected to a ground connection 48a of the vehicle 38a. The evaluation electronics 18a are also located in a protected area, spaced away from the sensor element 16a and the brake components 10a and 12a, so that the evaluation electronics 18a are not exposed to the harsh conditions in the area of ​​the brake components 10a and 12a.

[0026] To determine the distance parameter between the first braking component 10a and the second braking component 12a, the sensor element 16a is designed to emit a transmission signal 24a, in this case in particular in the form of an acoustic signal pulse, and to receive at least one reflection signal 26a, 28a correlated with the transmission signal 24a and in particular pulse-shaped, which can also be referred to as an echo signal (see in particular also Fig. 3, wherein in Fig. 3. An ordinate axis 54a is configured as a quantity axis, and a time is represented on an abscissa axis 56a). Furthermore, the evaluation electronics 18a are designed to determine the distance parameter based on a correlation between the transmitted signal 24a and the reflected signals 26a, 28a, and / or based on a correlation of several reflected signals 26a, 28a. In the present case, in which the first brake component 10a is configured as a brake pad and the sensor element 16a is integrated into the carrier element 20a, the evaluation electronics 18a are designed to determine the distance parameter based on a transit-time difference Δt2 between a first reflected signal 26a correlated with the transmitted signal 24a and a second reflected signal 28a correlated with the transmitted signal 24a. The first reflection signal 26a is generated at a first interface 50a between a surface of the brake pad 44a and air and follows immediately in time the transmission signal 24a.Therefore, the first reflection signal 26a is a first echo. The second reflection signal 28a is generated at a second interface 52a between air and the brake disc 12a and follows the first reflection signal 26a immediately in time. Therefore, the second reflection signal 28a is a second echo. Taking into account the specific velocity of the transmitted signal 24a and the second reflection signal 28a in air, the distance parameter can then be determined using the evaluation electronics 18a and the time-of-flight difference Δt2 between the first reflection signal 26a and the second reflection signal 28a. Multiple reflections can also detect further reflection signals, which, however, are filtered out or ignored in this case. An exact determination of the distance parameter, or...The use of air has several advantages in this context, particularly in the case of electric vehicles, where the range can be increased by about 6 km to 10 km per charging cycle, thus improving efficiency.

[0027] Furthermore, the evaluation electronics 18a can be used in this context to determine a brake pad thickness, or more precisely, a material thickness of the brake pad 44a, based on a correlation between the transmitted signal 24a and the reflected signal 26a, 28a, and / or based on a correlation of several reflected signals 26a, 28a. In the present case, in which the first brake component 10a is designed as a brake block and the sensor element 16a is integrated into the carrier element 20a, the evaluation electronics 18a are designed to determine the brake pad thickness based on a time difference Δt between the transmission of the transmitted signal 24a and the reception of the first reflected signal 26a. Taking into account the material of the brake pad 44a and the specific speed of the transmitted signal 24a, the evaluation electronics 18a can determine the brake pad thickness based on the time difference Δt between the transmission of the transmitted signal 24a and the reception of the first reflected signal 26a.The brake pad thickness can then be determined using the evaluation electronics 18a and the time difference Δt1 between the transmission of the transmit signal 24a and the reception of the first reflection signal 26a in this material. The subsequent reflection signals can also be filtered out or ignored in this case.

[0028] In the Fig. Figures 4 to 5b show further embodiments of the invention. The following description and the drawings are essentially limited to the differences between the embodiments, whereby with regard to identically designated components, in particular components with the same reference numerals, reference is also generally made to the drawings and / or the description of the other embodiments, in particular the Fig. 1 to 3, reference can be made. To distinguish the embodiments, the letter a is the reference numeral of the embodiment in the Fig. 1 to 3 are appended. In the exemplary embodiments of the Fig. In sections 4 to 5b, the letter a is replaced by the letters b and c.

[0029] In Fig. Figure 4 shows a first, further embodiment of the invention. The embodiment of Fig. In 4, the letter b is appended. The further example of the Fig. 4 differs from the previous embodiment at least substantially in a design of a sensor element 16b of a sensor unit 14b of a brake device.

[0030] A first brake component 10b of the brake device is essentially identical to the first brake component 10a of the previous embodiment.

[0031] A second brake component 12b of the brake device is essentially identical to the second brake component 12a of the previous embodiment. In this case, however, the second brake component 12b is additionally connected to a ground connection 48b of the vehicle.

[0032] The sensor element 16b is coupled to the first brake component 10b. However, the sensor element 16b is arranged and / or integrated into the first brake component 10b in such a way that the sensor element 16b and the second brake component 12b make contact when the brake is applied. Furthermore, the sensor element 16b is designed so that it wears down uniformly along with the first brake component 10b during operation. Therefore, the sensor element 16b is made of a suitable material that does not damage the second brake component 12b, withstands high temperatures, and does not wear down unevenly.

[0033] Furthermore, the sensor element 16b, according to the present embodiment, is designed as a capacitive sensor and is intended to detect an electrical capacitance in order to measure a distance parameter, in particular a clearance. For this purpose, the sensor element 16b comprises a measuring electrode 30b, which interacts with the second brake component 12b to measure the capacitance. The measuring electrode 30b is cylindrical, in particular circular cylindrical. The diameter of the measuring electrode 30b is larger than the maximum distance or air gap between the first brake component 10b and the second brake component 12b, particularly even when the brake components 10b and 12b are worn, thus enabling advantageously precise measurement of the distance parameter. The sensor element 16b is advantageously controlled by alternating current.Furthermore, an evaluation electronics unit 18b of the sensor unit 14b is provided to evaluate the capacitance determined by the sensor element 16b in order to determine the distance parameter. This calculation preferably follows the common methods of the capacitive distance sensors already available today.

[0034] The Fig. 5a and Fig. Figure 5b shows a further embodiment of the invention. The embodiment of Fig. 5a and Fig. In 5b, the letter c is appended. The further example of the Fig. 5a and Fig. 5b differs from the previous embodiments at least substantially in a design of a sensor element 16c of a sensor unit 14c of a brake device.

[0035] A first brake component 10c of the brake device is essentially identical to the first brake component 10b of the previous embodiment.

[0036] A second brake component 12c of the brake device is essentially identical to the second brake component 12b of the previous embodiment.

[0037] The sensor unit 14c of the brake device is essentially identical to the sensor unit 14b of the previous embodiment and comprises the sensor element 16c and evaluation electronics 18c that interact with the sensor element 16c. However, in this case, the sensor element 16c comprises a measuring electrode 30c, a shielding electrode 32c surrounding the measuring electrode 30c, and a separating element 34c arranged between the measuring electrode 30c and the shielding electrode 32c (see in particular the following). Fig.Figure 5b, which shows the sensor element 16c from the perspective of the second brake component 12c). The shielding electrode 32c and the separating element 34c are designed as hollow cylinders and arranged concentrically around the measuring electrode 30c. Furthermore, the shielding electrode 32c is connected to a ground connection 48c of the vehicle. This design allows, in particular, a homogenization of the field lines of the measuring electrode 30c and thus a further improvement in measurement accuracy. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 101 38 452 A1

[0002] DE 102 11 813 A1

[0003]

Claims

[1] Brake device comprising at least one first brake component (10a-c) and at least one second brake component (12a-c), which are designed to work together to provide a braking torque and are arranged in an unactuated state in a contactless manner and are movably mounted relative to each other, and comprising a sensor unit (14a-c), which is designed to determine a distance characteristic between the first brake component (10a-c) and the second brake component (12a-c), characterized by , that the sensor unit (14a-c) is designed to determine the distance parameter independently of brake actuation and comprises at least one non-contact measuring sensor element (16a-c) arranged on and / or integrated into the first brake component (10a-c) and an evaluation electronics (18a-c) that interacts with the sensor element (16a-c). [2] Brake device according to claim 1, characterized by, that the first brake component (10a-c) is designed as a brake pad and the second brake component (12a-c) is designed as a brake disc. [3] Brake device according to claim 1 or 2, characterized by , that the evaluation electronics (18a-c) is electrically connected to the sensor element (16a-c) and is arranged in a protected area spaced away from the brake components (10a-c, 12a-c). [4] Brake device according to one of the preceding claims, characterized by , that the sensor element (16a) is designed as a sound sensor, in particular as an ultrasonic sensor, or as a radar sensor. [5] Brake device according to claim 4, characterized by , that the first brake component (10a) comprises at least one support element (20a), in particular a pad carrier, and that the sensor element (16a) is arranged on the support element (20a), in particular attached, and / or integrated into the support element (20a). [6] Brake device according to claim 5, characterized by, that the sensor element (16a) is connected to the carrier element (20a) via an acoustic coupling agent (22a). [7] Brake device according to one of claims 4 to 6, characterized by , that the sensor element (16a) is designed as a combined transmitter and receiver unit and is intended to transmit a transmission signal (24a) and to receive at least one reflection signal (26a, 28a) correlated with the transmission signal (24a), wherein the evaluation electronics (18a) are intended to determine the distance parameter based on a correlation between transmission signal (24a) and reflection signal (26a, 28a) and / or based on a correlation of several reflection signals (26a, 28a). [8] Brake device according to claim 7, characterized by, that the evaluation electronics (18a) are designed to determine a brake pad thickness based on a correlation between the transmitted signal (24a) and the reflected signal (26a, 28a) and / or based on a correlation of several reflected signals (26a, 28a). [9] Brake device according to one of claims 1 to 3, characterized by , that the sensor element (16b; 16c) is designed as a capacitive sensor. [10] Brake device according to claim 9, characterized by , that the sensor element (16b; 16c) is arranged and / or integrated into the first brake component (10b; 10c) such that the sensor element (16b; 16c) and the second brake component (12b; 12c) touch when the brake is applied, wherein the sensor element (16b; 16c) is designed such that the sensor element (16b; 16c) wears down uniformly together with the first brake component (10b; 10c) during operation. [11] Brake device according to claim 9 or 10, characterized by, that the sensor element (16b; 16c) has a measuring electrode (30b; 30c) whose diameter is larger than a maximum distance between the first brake component (10b; 10c) and the second brake component (12b; 12c). [12] Brake device according to claim 11, characterized by , that the sensor element (16c) comprises a shielding electrode (32c) surrounding the measuring electrode (30c) and a separating element (34c) arranged between the measuring electrode (30c) and the shielding electrode (32c). [13] Wheel brake (36a), in particular friction brake, with a brake device according to one of the preceding claims. [14] Vehicle (38a), in particular motor vehicle, with at least one wheel brake (36a) according to claim 13. [15] Method for determining a distance parameter between a first brake component (10a-c) and a second brake component (12a-c) of a brake device, in particular according to one of claims 1 to 12, wherein the distance parameter is determined independently of a brake actuation and at least one non-contact measuring sensor element (16a-c) arranged on and / or integrated into the first brake component (10a-c) is used to detect the distance parameter.

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