Parking brake device for a motor vehicle

Abstract

Parking brake device (100) for a motor vehicle (200) comprising a first control unit (10) and a second control unit (11), a first parking brake actuator (12) and a second parking brake actuator (13), wherein the first control unit (10) is coupled to the first parking brake actuator (12) for controlling the first parking brake actuator (12), and wherein the second control unit (11) is coupled to the second parking brake actuator (13) for controlling the second parking brake actuator (13), and wherein the first control unit (10) and the second control unit (11) are coupled to each other via a communication line (18) for data transmission between the first control unit (10) and the second control unit (11), characterized in that the first control unit (10) is configured to set a higher clamping force level for the first parking brake actuator (12) in the event of a disturbance in the data transmission between the first control unit (10) and the second control unit (11).and / or that the second control unit (11) is configured to set a higher clamping force level for the second parking brake actuator (13) in the event of a disruption in data transmission between the first control unit (10) and the second control unit (11), wherein the first control unit (10) and / or the second control unit (11) is configured to receive environmental information and to set a higher clamping force level for the first parking brake actuator (12) and / or for the second parking brake actuator (13) only if there is a disruption in data transmission between the first control unit (10) and the second control unit (11) and the environmental information meets a predetermined criterion, the environmental information being an inclination of the motor vehicle (200), and the criterion being an exceedance of a predetermined minimum inclination.

Description

[0001] The present invention relates to a parking brake device for a motor vehicle comprising a first control unit and a second control unit, a first parking brake actuator and a second parking brake actuator, wherein the first control unit is coupled to the first parking brake actuator for controlling the first parking brake actuator, and wherein the second control unit is coupled to the second parking brake actuator for controlling the second parking brake actuator, and wherein the first control unit and the second control unit are coupled to each other via a communication line for data transmission between the first control unit and the second control unit.

[0002] Furthermore, the present invention relates to a computer program product and a motor vehicle comprising a parking brake device.

[0003] To secure a motor vehicle against rolling away, transmission parking locks and parking brake devices are known in the prior art. These parking brake systems represent two independent technical systems which, in the event of a failure of the other system, can completely take over the vehicle's ability to hold its position on a slope. Parking brake devices are usually coupled to the rear wheels of the motor vehicle and comprise one parking brake actuator for the first rear wheel (e.g., the right one) and another parking brake actuator for the second rear wheel (e.g., the left one). If one of the parking brake actuators fails, only the other parking brake actuator is operated. This can significantly reduce the vehicle's ability to hold its position on a slope.

[0004] In the prior art, distributed parking brake actuators are known, each connected to two control units via cross-wiring. If one control unit fails, the parking brake actuators are controlled via the remaining second control unit. This necessitates redundancy in the parking brake electronics, additional control electronics, and the cross-wiring of the parking brake actuators between the control units.

[0005] From DE 10 2020 005 759 A1, a parking brake device for a vehicle is known, comprising a control unit which is coupled to a wheel brake actuator of at least one wheel brake of the vehicle for controlling it to activate a parking brake function. The parking brake device also comprises a redundant further control unit which is coupled to a wheel brake actuator of at least one wheel brake of the vehicle for controlling it to activate the parking brake function.

[0006] The present invention is based on the objective of providing a parking brake device for a motor vehicle with which the ability to hold a slope can be ensured preventively in the event of a possible failure of a component of the parking brake device.

[0007] To solve the problem underlying the invention, a parking brake device for a motor vehicle is proposed, comprising a first control unit and a second control unit, a first parking brake actuator and a second parking brake actuator, wherein the first control unit is coupled to the first parking brake actuator for controlling the first parking brake actuator, and wherein the second control unit is coupled to the second parking brake actuator for controlling the second parking brake actuator, and wherein the first control unit and the second control unit are coupled to each other via a communication line for data transmission between the first control unit and the second control unit, and wherein it is further provided that the first control unit is configured to set a higher clamping force level for the first parking brake actuator in the event of a disturbance in the data transmission between the first control unit and the second control unit.and / or that the second control unit is designed to set a higher clamping force level for the second parking brake actuator in the event of a disruption in data transmission between the first and second control units.

[0008] In the parking brake device according to the invention, a first control unit is coupled to a first parking brake actuator for controlling, in particular for activating a parking brake function, the first parking brake actuator. Furthermore, a second control unit is coupled to a second parking brake actuator for controlling, in particular for activating a parking brake function, the second parking brake actuator. The first control unit and the second control unit are also coupled to each other via a communication line, whereby data transmission between the first and second control units can take place via the communication line.

[0009] If the first and / or the second control unit receives a request, for example from a parking brake button pressed by a driver of the vehicle, to activate the parking brake function, the first control unit controls the first parking brake actuator and / or the second control unit controls the second parking brake actuator in order to activate the respective parking brake function.

[0010] According to the invention, the first control unit is designed to set a higher clamping force level for the first parking brake actuator in the event of a disruption in data transmission between the first control unit and the second control unit, and / or the second control unit is designed to set a higher clamping force level for the second parking brake actuator in the event of a disruption in data transmission between the first control unit and the second control unit.

[0011] For this purpose, the first and / or the second control unit is preferably designed to detect a data transmission fault. If a data transmission fault occurs and is detected, for example, by the first control unit, the first control unit is designed to set a higher clamping force level for the first parking brake actuator coupled to it in order to ensure hillside stability. Alternatively or additionally, the second control unit can also be designed to detect a data transmission fault between the first and second control units and, in the event of a data transmission fault, to set a higher clamping force level for the second parking brake actuator coupled to it.

[0012] In contrast to prior art parking brake devices, the increase in the clamping force level for the first and / or the second parking brake actuator occurs depending on a detected fault in the data transmission between the first and second control units. This is therefore a preventive increase in the clamping force level, which occurs as soon as the first and / or second control unit no longer receives data from the other control unit, and not only when an actual failure of one of the control units or one of the parking brake actuators has occurred.It is therefore possible that both the first and second parking brake actuators are fully functional, and that the control of both actuators by the first and second control units functions without impairment, but that only the data transmission between the first and second control units is disrupted. In this case, a higher clamping force level is also set preventively for the first and / or second parking brake actuator.

[0013] Similarly, a data transmission disruption between the first and second control units can also occur if the first and / or second control unit and / or the first and / or second parking brake actuators are actually impaired or have failed with regard to activating the parking brake function. In this case, too, the first and / or second control unit can set a higher clamping force level for the first and / or second parking brake actuators.

[0014] Preferably, the first control unit and / or the second control unit is configured to adjust the higher clamping force level by increasing a shutdown current.

[0015] If the first and / or second control unit detects a data transmission fault between the two control units, the shutdown current for the first and / or second parking brake actuator connected to the respective control unit is increased. If the data transmission fault between the first and second control units occurs while the parking brake function is already activated, the increased shutdown current results in an increase in the locking force or an additional build-up of clamping force when the parking brake actuator is already closed.

[0016] It is therefore preferable that the first control unit and / or the second control unit is configured to adjust the higher clamping force level by reactivating the parking brake actuator coupled to the respective control unit, preferably with the increased cut-off current.

[0017] In principle, it is also possible for the higher clamping force level to be set even if the parking brake actuators are not yet closed. The first and / or second control unit then prepares itself to immediately activate the first and / or second parking brake actuator with a higher clamping force level, for example by increasing the cut-off current, when a parking brake function is requested, for example by a driver pressing a corresponding parking button. In this case, a higher clamping force level is assumed even when the first and / or second parking brake actuators are initially closed.

[0018] A further advantage is that the first control unit and / or the second control unit can be designed to adjust the higher clamping force level by increasing the hydraulic pressure.

[0019] To increase hydraulic pressure, the first control unit and / or the second control unit that has detected the data transmission fault can request hydraulic brake assistance with increased hydraulic pressure from a hydraulic brake control system. This increase in hydraulic pressure provides a higher clamping force level for the first parking brake actuator and / or the second parking brake actuator.

[0020] A further advantage is that the disruption of data transmission can be provided for by an interruption of the communication line and / or a failure or partial failure of the first control unit and / or the second control unit.

[0021] As explained above, a data transmission fault can also occur without the first and / or second control unit and / or the first and / or second parking brake actuator actually being impaired or failing with regard to activating the parking brake function. Such a fault can be caused, for example, by a break in the communication line. The data transmission fault can also be due to a software problem or a failure or partial failure of communication modules in the respective control units that are responsible for data transmission between the first and second control units. In these cases as well, the control unit detecting the data transmission fault will increase the clamping force level for the parking brake actuator connected to the respective control unit.

[0022] Furthermore, it may be provided that the communication line is a vehicle bus, or that the communication line is a data bus, in particular a CAN bus, which is preferably provided in addition to a vehicle bus, or that the communication line is an electrical connection.

[0023] If an existing vehicle bus is used for data transmission between the first and second control units, the advantageous slope stabilization can be achieved without adding weight to the parking brake system. Alternatively, an additional data bus, particularly a CAN bus, or an additional electrical connection can be provided for the communication line. Such communication lines are also lightweight, thus avoiding the complex and heavy cross-wiring known from the prior art.

[0024] With a further advantage, it can be provided that the first control unit and / or the second control unit is designed to receive environmental information and to set a higher clamping force level for the first parking brake actuator and / or for the second parking brake actuator only if there is a disturbance in the data transmission between the first control unit and the second control unit and the environmental information meets a predetermined criterion.

[0025] Preferably, the environmental information is the inclination of the motor vehicle, and the criterion is an exceedance of a predetermined minimum inclination.

[0026] Ensuring the vehicle's ability to hold its position on a slope by increasing the clamping force level is therefore only necessary if the vehicle is to be secured against rolling on a slope with a predetermined incline or gradient.

[0027] Another solution to the problem underlying the invention consists in a computer program product comprising commands which, when the program is executed by a first control unit and / or a second control unit of a previously described parking brake device, in the event of a disruption in data transmission between the first control unit and the second control unit, cause the first control unit to set a higher clamping force level for the first parking brake actuator, and / or cause the second control unit to set a higher clamping force level for the second parking brake actuator.

[0028] Another solution to the problem underlying the invention consists of a motor vehicle comprising a parking brake device as described above.

[0029] All the features, advantages and functions described above relating to the parking brake device can be transferred accordingly to the computer program product or the motor vehicle.

[0030] Preferably, the motor vehicle includes environmental sensors designed to determine environmental information and transmit it to the first control unit and / or the second control unit, preferably via a vehicle bus.

[0031] Further preferred are the environmental sensors tilt sensors for determining the tilt of the motor vehicle.

[0032] The invention is explained in more detail below with reference to the attached figures.

[0033] They show: Fig. 1 a schematic representation of a first parking brake device, Fig. 2 a schematic representation of a second parking brake device, and, Fig. 3. Supervision of a motor vehicle equipped with a parking brake device.

[0034] Fig. Figure 1 shows a schematic representation of a parking brake device 100 in accordance with the invention for, for example, a top view according to Fig. Figure 3 shows a motor vehicle 200. The parking brake device 100 comprises a first control unit 10 and a second control unit 11, as well as a first parking brake actuator 12 and a second parking brake actuator 13. The first control unit 10 is connected to the first parking brake actuator 12 via a first control line 14. The first control unit 10 can activate a parking brake function of the first parking brake actuator 12 via the first control line 14. The second control unit 11 is connected to the second parking brake actuator 13 via a second control line 15. The second control line allows the second control unit 11 to activate a parking brake function of the second parking brake actuator 13. The first parking brake actuator 12 is connected to a Fig. The first rear wheel 16 of the motor vehicle 200 shown in 3 is assigned and the second parking brake actuator 13 is assigned to a second rear wheel 17 of the motor vehicle 200.

[0035] The first control unit 10 and the second control unit 11 are coupled to each other via a communication line 18 for data transmission between them. In addition, the first control unit 10 and the second control unit 11 can also be connected to each other via a vehicle bus 19. A computer program 300 for detecting a fault in the data transmission via the communication line 18 between the first control unit 10 and the second control unit 11 is executed on both the first control unit 10 and the second control unit 11. Furthermore, software 20 for controlling the first parking brake actuator 12 is executed on the first control unit 10. Similarly, software 20 for controlling the second parking brake actuator 13 is also executed on the second control unit 11.If a data transmission fault occurs between the first control unit 10 and the second control unit 11, which can be caused, for example, by a mechanical interruption of the communication line 18 or by a partial or complete failure of the first control unit 10 and / or the second control unit 11, both the first control unit 10 and the second control unit 11, or, in the event of a failure of one of the control units 10, 11, the other control unit 10, 11, detect the data transmission fault. After the data transmission fault has been detected, the first control unit 10 and the second control unit 11, or, in the event of a failure of one of the control units 10, 11, the other control unit 10, 11, increase the clamping force level for the parking brake actuator 12, 13 assigned to the respective control unit 10, 11.This means that if a parking brake actuator 12, 13 was previously open, a higher clamping force is applied when the parking brake actuator 12, 13 is initially closed. However, if the first parking brake actuator 12 and / or the second parking brake actuator 13 are already closed when the data transmission fault occurs, the corresponding parking brake actuator 12, 13 is again actuated with an increased clamping force.

[0036] In a further embodiment of the parking brake device 100 according to Fig.2. The motor vehicle 200 also has a hydraulic system 21, which is connected to the parking brake actuators 12 and 13. In this case, increasing the clamping force level of the first parking brake actuator 12 and / or the second parking brake actuator 13 can be supported by providing increased hydraulic pressure, with the increase being transmitted to the hydraulic system 21 via the vehicle bus 19 at the request of the first control unit 10 and / or the second control unit 11. Furthermore, the motor vehicle 200 has tilt sensors 22. The first control unit 10 and the second control unit 11 receive information about the tilt of the motor vehicle 200 from these sensors.In one variant of the parking brake device 100, it can then be provided that an increase in the clamping force level for the first parking brake actuator 12 and / or the second parking brake actuator 13 only takes place if at the same time there is a disturbance of the data transmission via the communication line 18 and a minimum inclination of the motor vehicle 200 is exceeded. Reference symbol list 100 Parking brake device 200 motor vehicles 300 computer program product 10 First control unit 11 Second control unit 12 First parking brake adjuster 13 Second parking brake adjuster 14 First control line 15 Second control line 16 First rear wheel 17 Second rear wheel 18 Communications Management 19 vehicle buses 20 Software 21 Hydraulic system 22 Tilt sensor 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 102020005759 A1

[0005]

Claims

[1] Parking brake device (100) for a motor vehicle (200) comprising a first control unit (10) and a second control unit (11), a first parking brake actuator (12) and a second parking brake actuator (13), wherein the first control unit (10) is coupled to the first parking brake actuator (12) for controlling the first parking brake actuator (12), and wherein the second control unit (11) is coupled to the second parking brake actuator (13) for controlling the second parking brake actuator (13), and wherein the first control unit (10) and the second control unit (11) are coupled to each other via a communication line (18) for data transmission between the first control unit (10) and the second control unit (11), characterized by, that the first control unit (10) is designed to set a higher clamping force level for the first parking brake actuator (12) in the event of a disruption in data transmission between the first control unit (10) and the second control unit (11), and / or that the second control unit (11) is designed to set a higher clamping force level for the second parking brake actuator (13) in the event of a disruption in data transmission between the first control unit (10) and the second control unit (11). [2] Parking brake device (100) according to claim 1, characterized by , that the first control unit (10) and / or that the second control unit (11) is designed to adjust the higher clamping force level by increasing a shutdown current. [3] Parking brake device (100) according to claim 1 or 2, characterized by, that the first control unit (10) and / or that the second control unit (11) is configured to adjust the higher clamping force level by reactivating the parking brake actuator (12, 13) coupled to the respective control unit (10, 11), preferably with the increased cut-off current. [4] Parking brake device (100) according to one of the preceding claims, characterized by , that the first control unit (10) and / or that the second control unit (11) is designed to adjust the higher clamping force level by increasing a hydraulic pressure. [5] Parking brake device (100) according to one of the preceding claims, characterized by , that the disruption of data transmission is an interruption of the communication line (18) and / or a failure or partial failure of the first control unit (10) and / or the second control unit (11). [6] Parking brake device (100) according to one of the preceding claims, characterized bythat the communication line (18) is a vehicle bus (19), or that the communication line (18) is a data bus, in particular a CAN bus, which is preferably provided in addition to a vehicle bus (19), or that the communication line (18) is an electrical connection. [7] Parking brake device (100) according to one of the preceding claims, characterized by , that the first control unit (10) and / or the second control unit (11) is designed to receive environmental information and to set a higher clamping force level for the first parking brake actuator (12) and / or for the second parking brake actuator (13) only if there is a disruption in the data transmission between the first control unit (10) and the second control unit (11) and the environmental information meets a predetermined criterion. [8] Parking brake device (100) according to claim 7, characterized by, that the environmental information is an inclination of the motor vehicle (200), and that the criterion is an exceedance of a predetermined minimum inclination. [9] Computer program product (300), comprising commands which, when the program is executed by a first control unit (10) and / or a second control unit (11) of a parking brake device (100) according to one of the preceding claims, in the event of a disruption in data transmission between the first control unit (10) and the second control unit (11), cause the first control unit (10) to set a higher clamping force level for the first parking brake actuator (12), and / or cause the second control unit (11) to set a higher clamping force level for the second parking brake actuator (13). [10] Motor vehicle (200) comprising a parking brake device (100) according to any one of claims 1 to 8.

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