Braking system for a vehicle and vehicle

Abstract

The invention relates to a braking system (10) for a vehicle with at least one driven axle, which is connected to at least one motor via a power transmission device comprising at least one gearbox (16) and has a parking lock (18) for blocking the power transmission device, wherein the braking system (10) has a parking brake (14) for blocking at least one wheel of the vehicle and a hydraulic service brake (22) for decelerating the vehicle during driving, wherein the parking lock (18), the parking brake (14) and the service brake (22) can be actuated independently of one another, wherein the vehicle can be secured at least by means of the parking lock (18) and / or the parking brake (14), wherein the braking system (10) includes a device configured to detect a malfunction of the parking lock (18) and, in the event of a malfunction of the parking lock (18),Alternatively, the hydraulic service brake (22) can be applied and / or the clamping force of the parking brake (14) can be increased to prevent unwanted rolling. The braking system (10) improves the vehicle's ability to hold its position on slopes in the event of a failure of the parking lock (18), is simple in design and cost-effective.

Description

[0001] The invention relates to a braking system for a vehicle and a vehicle.

[0002] When parking vehicles or during short-term stops, especially in parking areas or on roads with a steep incline, it is common practice, for example with passenger cars, to apply or activate a parking brake, such as an electronic parking brake. This allows the vehicle to be securely locked in place and prevented from rolling away.

[0003] Vehicles with automatic transmissions typically also have a parking lock engaged. The function of the parking lock is to block the rotation of the transmission output shaft, thus preventing the vehicle from rolling away. If the vehicle is parked on level ground or on a slight incline, simply engaging the parking lock may be sufficient to ensure adequate stability and secure the vehicle.

[0004] To ensure the desired braking or locking function of a parking lock is maintained even if the automatic transmission's parking lock fails, DE 10 2013 009 747 A1 discloses the method of designing the parking brake redundantly to the parking lock, and applying the parking brake as a substitute in the event of a parking lock failure. If a driver parks the vehicle using only the parking lock and the parking lock fails, the parking brake automatically takes over and fulfills the locking function. Since the parking brake alone provides the braking force required to secure the vehicle, it must, by its very nature, be designed as a bidirectional parking brake. This necessitates a relatively high number of hardware components when installing the parking brake and increases manufacturing costs.

[0005] Furthermore, vehicles with internal combustion engines and electronically controlled automatic transmissions are known from EP 0972667 B1 and DE 198 31 733 A1, respectively, which provide a parking lock and an externally operated parking brake that technically compensate for each other in the event of a failure. In vehicles that, for example, use both the parking lock and the parking brake as standard for securing the vehicle and which may be partially reduced in size, these systems cannot guarantee sufficient support in the event of a parking lock failure.

[0006] From DE 10 2018 213 848 A1 it is known to actuate a vehicle's braking device when movement of the vehicle is detected while the parking brake is engaged. A parking brake can be engaged manually or automatically.

[0007] DE 10 2019 213 402 A1 relates to a method for securing a vehicle that has an automatic parking brake on at least one wheel. The parking brake can be controlled via a control device.

[0008] Furthermore, it is known from DE 10 2012 217 704 A1 to activate a parking lock in the event of a service brake failure while driving, in particular by means of an autonomous driver assistance system.

[0009] The object of the invention is to provide a braking system for a vehicle that is simple and cost-effective in design and improves the vehicle's ability to hold its position on slopes in the event of a failure of the parking lock.

[0010] The problem is solved by the features of the independent claims. Advantageous further developments are the subject of the dependent claims and the following description.

[0011] According to a first aspect, a braking system for a vehicle with at least one driven axle is described, which is connected to at least one motor via a power transmission device comprising at least one gearbox and has a parking lock for blocking the power transmission device, wherein the braking system has a parking brake for blocking at least one wheel of the vehicle and a hydraulic service brake for decelerating the vehicle during driving, wherein the parking lock, the parking brake and the service brake can be actuated independently of one another, wherein according to the invention it is provided that the vehicle can be secured at least by means of the parking lock and / or the parking brake, wherein the braking system includes a device which is configured to detect a malfunction of the parking lock and, when the parking lock and the parking brake are actuated, in the event of a malfunction of the parking lock,Alternatively, the hydraulic service brake can be applied and / or the clamping force of the parking brake increased to prevent unwanted rolling.

[0012] The braking system thus detects a failure of the parking lock and simultaneously ensures that sufficient braking force support is always available in the event of a parking lock failure. In failure situations, the parking lock is effectively replaced by the hydraulic service brake and / or by an increase in the tension of the parking brake, so that the parking brake is supported with additional braking force when the parking lock fails. This ensures sufficient braking force is provided even in systems that, under normal operating conditions, use the parking lock in addition to the parking brake when securing the vehicle, and the parking brake can be effectively supported by the service brake in the event of a parking lock failure. It is also conceivable that the transmission could be an automatic transmission with a parking lock.

[0013] If the vehicle always uses the parking lock in addition to the parking brake, the braking force of the parking brake can be reduced accordingly. Overall, sufficient holding power on inclines, or generally sufficient holding power in the vehicle's fixed position, can still be provided. This effectively reduces manufacturing costs. At the same time, the vehicle weight can be reduced. Furthermore, the hydraulic service brake is already standard equipment in most vehicles, so no additional costs for new hardware components arise in this respect.

[0014] By incorporating the hydraulic service brake to assist the parking brake in the event of a parking lock failure, an additional source of braking force is created or integrated. This can advantageously, for example, allow the parking brake connection to be located exclusively on one side of the vehicle. This can further reduce production costs and make the braking system more cost-effective to manufacture overall.

[0015] A fixed vehicle state is, for example, a situation where the vehicle is parked in a parking space, with or without a slope, and should not move or roll away. Another fixed state can occur, for example, when driving uphill, if the vehicle needs to come to a brief standstill and then accelerate again. To prevent the vehicle from rolling backward unintentionally, the parking lock and parking brake can be engaged to securely lock the vehicle in place.

[0016] The ability to hold on slopes, or more generally, holding capability, refers to the ability to securely block or fix the vehicle against rolling away when the vehicle is parked on level ground, on a slight incline, or on a steep slope.

[0017] According to some embodiments, it is conceivable that the vehicle's parking brake may only be installed on one side of the vehicle and may have corresponding hardware components for applying a braking force to one wheel.

[0018] This simplifies the manufacturing of the parking brake within the braking system and reduces the number of hardware components required. Furthermore, it reduces manufacturing costs and simultaneously lowers the vehicle weight. If the parking lock is used in addition to the parking brake, it can compensate for the missing parking brake on the other side, thus enabling the use of the parking lock to create a parking brake on both sides.

[0019] The braking system can thus provide standstill management in which the parking brake on one side of the vehicle can be omitted and only installed on one side. The omitted portion of the parking brake can be supplemented by the parking lock to ensure, together with the parking brake, the vehicle's ability to hold its position on inclines. In the event of a parking lock failure, the one-sided parking brake may, by design, provide less braking force. This can be compensated for by the support of the hydraulic service brake. Generally, when the parking brake is supported by the hydraulic service brake, the sum of the (electro)mechanical clamping force and the hydraulic clamping force can be used to generate a total braking force.

[0020] According to some embodiments, it is conceivable that the parking brake can be designed as one half of a double-acting parking brake.

[0021] A standard parking brake that acts on both sides can be reduced to just one side and installed on only one side of the vehicle. This significantly reduces material and component costs because the single-sided design allows all hardware components of the parking brake or standard electric parking brake (EPB) system to be halved. This halves the number of hardware components used and also reduces associated failure modes of the parking brake, such as jamming, freezing, and locking. Furthermore, the standard identical parking brake design can be used on both sides of the vehicle, meaning that only one parking brake needs to be installed compared to the double-sided version.The parking brake can remain unchanged due to the assistance provided by the parking lock on the remaining side, and modifications to the parking brake design, particularly a larger size, are unnecessary. Larger size refers to the capacity to apply the necessary braking or clamping force to lock a wheel.

[0022] According to some embodiments, it is conceivable that the device may include at least one electronic transmission control unit for operating the transmission and at least one electronic brake control unit for operating the parking brake and the hydraulic service brake, wherein both control units may be connected via a signal link and exchange information about the respective operating status and proper functioning of the respective associated system.

[0023] According to some embodiments, it is conceivable that the parking lock, the parking brake and the hydraulic service brake could be electronically actuated.

[0024] Through the signal connection, which can be wired or wireless, and the electronic actuation of the brakes and parking lock, the control units can communicate with the individual components of the braking system and with each other. This means they can exchange and temporarily store data and information for further processing. Furthermore, this allows for the creation of redundant systems with minimal effort, enabling mutual support. The control units can activate the required components of the braking system via braking requests or control commands. Both the transmission and brake units can be controlled and regulated using appropriate algorithms. The transmission control unit, for example, can be used to detect a malfunction of the parking lock and report it to the brake control unit.The brake control unit can still be used to control the service brake in the event of a malfunction.

[0025] In some embodiments, the parking brake and the hydraulic service brake can be designed as redundant systems for the parking lock.

[0026] This allows, for example, the service brake to take over the function of the parking brake in the event of a malfunction, or one system can take over the function of another if another system fails. This ensures that the vehicle is always secured against rolling away in its designated state. Furthermore, this design guarantees the full range of functionality provided by the three subsystems during normal operation. If one system fails, the other system automatically takes over its function. This also increases convenience, as the driver no longer needs to worry about whether to engage the parking brake or the parking / service brake. Overall, the redundant design also improves the energy efficiency of the braking system.

[0027] According to some embodiments, it is conceivable that the device may be designed to support the parking brake by actuating the hydraulic service brake with a maximum possible hydraulic brake pressure in the event of a failure of the parking lock.

[0028] This further improves safety in the vehicle's fixed position and its ability to hold on inclines, or indeed its overall holding power. This function of the braking system maximizes holding power in the event of a parking lock failure, requiring only minor modifications to existing components. Furthermore, it avoids adding weight, as the single-sided design of the parking brake actually reduces weight. This makes the function cost-effective in both design and implementation.

[0029] According to some embodiments, it is conceivable that the device includes at least one control unit for providing a failure control request and for actuating the hydraulic service brake when a malfunction of the parking lock occurs. It is also conceivable that the failure control request could additionally support automatic actuation of the service brake.

[0030] In some embodiments, the brake control unit can have at least one control unit, the control unit being integrated into the brake control unit.

[0031] The control unit can be configured as a standstill coordinator, which can be designed to transmit the failure control request to the service brake via the signal connection and request hydraulic brake pressure for support. The standstill coordinator can be integrated into the brake control unit. A failure signal can be provided or sent when the parking lock fails and the connected transmission control unit provides a corresponding signal. The service brake can then be automatically applied via the failure control request as soon as the brake control unit or the control unit has identified the parking lock failure.

[0032] According to some embodiments, it is conceivable that the hydraulic service brake can be adjusted depending on the vehicle's longitudinal inclination, whereby the braking force of the hydraulic service brake can increase with increasing longitudinal inclination and, after exceeding a longitudinal inclination threshold, can support the parking brake with maximum possible braking pressure. Furthermore, it is conceivable that the hydraulic service brake can also be regulated depending on the vehicle's total mass, so that the hydraulic brake pressure can increase with increasing vehicle weight. It is also conceivable that appropriate sensors can be provided to measure the necessary parameters such as longitudinal inclination angle, vehicle mass, etc. This allows the braking system to be more efficient in operation and to apply the required braking force resources with a high degree of safety without providing excessive support.

[0033] In some embodiments, the parking brake may include an actuator which may have reserves for applying additional braking force beyond the standard design of the parking brake, wherein the device may be designed to support the parking brake by means of the actuator through additional braking force reserves in the event of a failure of the parking lock.

[0034] Applying additional braking force beyond the standard parking brake setting via the parking brake actuator can be done either as an alternative or in addition to the support provided by the hydraulic service brake. In the alternative configuration, the braking force can be applied purely electromechanically when the vehicle is locked, as the parking brake's reserves allow it to act more effectively, replacing the parking lock or compensating for the braking force lost through it.

[0035] According to some embodiments, it is conceivable that the brake control unit could have a counter element for incrementing each malfunction of the parking lock and the service brake's assist function. It is further conceivable that the counter element could be implemented as a software function in the brake control unit of the system.

[0036] This allows for continuous monitoring of the increased clamping and braking forces, and the associated component stresses, that can occur due to the additional support provided by the hydraulic service brake in the event of a parking lock failure. Predictable component failures can thus be detected early and proactively by the counter element, enabling appropriate maintenance measures to be carried out or individual components to be replaced. This can be done when a specific, predefined limit is reached, corresponding to a numerical value on the counter element, which is incremented by each parking lock failure and service brake support operation. This allows the braking system to improve vehicle safety in a defined state and provide safe standstill management.By replacing components that wear out prematurely, unexpected component failures and accident risks can be avoided.

[0037] According to some embodiments, it is conceivable that the parking brake could be designed as a combined floating caliper system. Furthermore, it is conceivable that the hydraulic service brake could be designed as a combined floating caliper brake system. It is also conceivable that the parking brake could be designed as a parking brake that allows hydraulic assistance via the service brake.

[0038] This allows for hydraulic assistance of the parking brake, as the floating caliper design facilitates hydraulic connection and support via the service brake without requiring further modifications. It is conceivable that the parking brake and its associated brake control unit could include a functional interface through which the hydraulic brake pressure and the resulting additional braking force could be directly requested via the service brake. This would further support simple and efficient integration of the function into the vehicle's system at the software level.

[0039] According to some embodiments, it is conceivable that a central control element could be provided for operating the transmission and the transmission control unit. For the parking lock, this could, for example, be the "P" position in an automatic transmission. Furthermore, it is conceivable that a control element could be provided for operating the brake control unit and the parking brake and / or the hydraulic service brake. For manual operation of the hydraulic service brake while driving, a corresponding brake pedal could be provided in the vehicle.

[0040] According to a second aspect, a vehicle is described that includes a braking system as described above.

[0041] The vehicle's transmission could, for example, be an electronically controlled automatic transmission. The parking brake could be a single-sided electric parking brake (EPB). It's conceivable that, to create the desired single-sided parking brake, a standard double-acting EPB could be modified by half and installed on only one side of the vehicle. It's also possible that the parking lock could be an automated parking lock. Furthermore, it's conceivable that the vehicle could have all-wheel drive.

[0042] The advantages, effects, and further developments of the vehicle result from the advantages, effects, and further developments of the braking system described above. Therefore, reference is made to the preceding description in this regard.

[0043] The invention is described below with reference to an exemplary embodiment and the accompanying drawing. The drawing shows: Fig. 1 a schematic representation of a braking system for a vehicle; and Fig. 2 a schematic representation of a vehicle.

[0044] The braking system for a vehicle is hereinafter referred to in its entirety by reference numeral 10, as in the Fig. 1 shown.

[0045] The braking system 10 can conveniently be installed with all its individual components in a vehicle 34 according to Fig. 2 be installed. Vehicle 34 can, for example, be a multi-track passenger car.

[0046] The braking system 10 for a vehicle 34 shown in this embodiment can comprise at least one driven axle which can be connected to a motor via a power transmission device comprising a gearbox 16 and can have a parking lock 18 for blocking the power transmission device.

[0047] The braking system 10 also includes a parking brake 14 for locking at least one wheel of the vehicle 34 and a hydraulic service brake 22 for decelerating the vehicle 34 during driving. The parking lock 18, the parking brake 14, and the hydraulic service brake 22 can be actuated independently of one another, whereby the vehicle 34 can be secured at least by means of the parking lock 18 and / or the parking brake 14.

[0048] The braking system 10 includes a device designed to detect a malfunction of the parking lock 18 and, in the event of a malfunction of the parking lock 18, to actuate the hydraulic service brake 22 as a substitute and / or to increase the tension force of the parking brake 14 in order to prevent unwanted rolling away.

[0049] The device may include at least one electronic transmission control unit 20 for operating the transmission 16 and at least one electronic brake control unit 12 for operating the parking brake 14 and the hydraulic service brake 22, wherein both control units 12, 20 may be bidirectionally connected via a signal connection 26 and may exchange information about a respective operating status and proper functioning of the respective associated system.

[0050] The device can further be designed to assist the parking brake 14 in the event of a malfunction of the parking lock 18 by actuating the hydraulic service brake 22 with a maximum possible hydraulic brake pressure.

[0051] The device can include a control unit 13 for providing a failure control request 24. The control unit 13 can actuate the hydraulic service brake 22 if a malfunction of the parking lock 18 occurs. The failure control request 24 can automatically trigger actuation of the service brake as soon as a malfunction of the parking lock 18 is detected.

[0052] The control unit 13 can be configured as a standstill coordinator, which can be configured to send the failure control request 24 via the signal connection to the service brake 22 and to request the hydraulic brake pressure to assist the parking brake 14 when the vehicle 34 is secured. The standstill coordinator or the control unit 13 can be integrated into the brake control unit. In this case, a failure signal can be provided or sent when the parking lock 18 fails and the connected transmission control unit 20 provides a corresponding signal. The service brake 22 can be automatically actuated via the failure control request 24 as soon as the brake control unit 12 or the control unit 13 has identified the failure of the parking lock 18.

[0053] The hydraulic service brake 22 can also be adjusted depending on the longitudinal inclination of the vehicle 34, whereby the hydraulic service brake 22 can increase with increasing longitudinal inclination and, after exceeding a longitudinal inclination threshold, can assist the parking brake 14 with maximum possible braking pressure. The hydraulic service brake 22 can also be regulated depending on the total vehicle mass, so that the hydraulic brake pressure can increase with increasing vehicle weight and take into account weight increases, for example, due to luggage.

[0054] The transmission control unit 20 and the brake control unit 12 can transmit / receive signals via corresponding data buses 28 and control the parking lock 18, the parking brake 14 and the service brake 12 via predefined transmission and brake algorithms.

[0055] The transmission 16 can be an electronically actuated automatic transmission with an electronic parking lock 18. The parking brake 14 can be an electric parking brake (EPB) installed on only one side. The parking lock 18, the parking brake 14, and the hydraulic service brake 22 can be electronically actuated. The parking brake 14 and the hydraulic service brake 22 can be designed as redundant systems for the parking lock.

[0056] Via the signal connection 26 and the electronic actuation of the brakes 14, 22 and the parking lock 18, the control units 12, 20 can communicate with the individual components of the brake system 10 and with each other; that is, they can exchange, process, and temporarily store data and information for further processing, etc. The transmission control unit 20 can, for example, be used to detect a malfunction of the parking lock 18 and report it to the control unit 13 of the brake control unit 12. The brake control unit 12 can further be used to automatically control and actuate the hydraulic service brake 22 in the event of a malfunction of the parking lock 18.

[0057] The electric parking brake 14 of the vehicle 34 can only be installed on one side of the vehicle 34 and must include corresponding hardware components for applying a braking force to one wheel. To form the desired one-sided parking brake 14, as described in the Fig. 1 and Fig. As shown in Figure 2, a standard double-acting EPB can be reduced by half and installed on one side of vehicle 34.

[0058] The parking brake 14 may include an actuator that has reserves for applying additional braking force beyond the standard design of the parking brake 14. Alternatively or in addition to the hydraulic brake force assistance via the service brake, the device may be designed to support the parking brake by means of the actuator with additional braking force reserves in the event of a failure of the parking lock.

[0059] The brake control unit can include a counter element 32 for incrementing each functional failure of the parking lock 18 and the assist operation of the service brake 22. The counter element 32 can, for example, be implemented directly as a software function in the brake control unit 12 of the device.

[0060] The electric parking brake 14 can be designed as a so-called combination floating caliper. The hydraulic service brake 22 can also be designed as a combination floating caliper brake system. The parking brake 14 can expediently be designed as a parking brake that allows hydraulic assistance via the service brake of a vehicle.

[0061] A central control element 30 may be provided for actuating and operating the parking lock 18 and for operating the transmission and the transmission control unit. The parking lock 18 may be the familiar P position or Auto-P in an automatic transmission.

[0062] A control element 30' may be provided for operating the brake control unit 12 and the electric parking brake 14 and / or the hydraulic service brake 22. A corresponding brake pedal may be provided in the vehicle 34 for manual operation of the hydraulic service brake 22 while driving.

[0063] The example described above does not in any way limit the invention. Rather, the invention can be modified in numerous ways. All features of the invention described above can be essential to the invention, either alone or in combination.

Claims

[1] Braking system (10) for a vehicle with at least one driven axle, which is connected to at least one motor via a power transmission device comprising at least one gearbox (16) and has a parking lock (18) for blocking the power transmission device, wherein the braking system (10) has a parking brake (14) for blocking at least one wheel of the vehicle and a hydraulic service brake (22) for decelerating the vehicle during driving, wherein the parking lock (18), the parking brake (14) and the service brake (22) can be actuated independently of each other, characterized by, that the vehicle can be secured at least by means of the parking lock (18) and / or the parking brake (14), wherein the braking system (10) includes a device designed to detect a malfunction of the parking lock (18) and, when the parking lock and the parking brake are actuated, in the event of a malfunction of the parking lock (18), to actuate the hydraulic service brake (22) as a substitute and / or to increase a clamping force of the parking brake (14) in order to prevent unwanted rolling away. [2] Braking system according to claim 1, characterized by , that the parking brake (14) of the vehicle is installed only on one side of the vehicle and has corresponding hardware components for applying a braking force to one wheel. [3] Braking system according to claim 1 or 2, characterized by, that the device comprises at least one electronic transmission control unit (20) for operating the transmission (16) and at least one electronic brake control unit (12) for operating the parking brake (14) and the hydraulic service brake (22), wherein both control units (20, 12) are connected via a signal connection (26) and can exchange information about a respective operating status and proper functioning of the respective associated system. [4] Braking system according to any of the preceding claims, characterized by , that the parking lock (18), the parking brake (14) and the hydraulic service brake (22) are electronically operable. [5] Braking system according to any of the preceding claims, characterized by, that the device is designed to assist the parking brake (14) by applying the hydraulic service brake (22) with a maximum possible hydraulic brake pressure in the event of a failure of the parking lock (18). [6] Braking system according to any of the preceding claims, characterized by , that the device has at least one control unit (13) for providing a failure control request (24) for actuating the hydraulic service brake (22) when a malfunction of the parking lock (18) occurs. [7] Braking system according to any of the preceding claims, characterized by, that the parking brake (14) includes an actuator which has reserves for applying additional braking force beyond the standard design of the parking brake (14), wherein the device is designed to support the parking brake (14) by means of the actuator by means of additional braking force reserves in the event of a failure of the parking lock (18). [8] Braking system according to any of the preceding claims, characterized by , that the brake control unit (12) has a counter element (32) for incrementing each failure of the parking lock (18) and service brake support operation (22). [9] Brake system according to any of the preceding claims, characterized by , that the parking brake (14) is designed in a combination floating caliper design. [10] Vehicle (34) with a braking system (10) according to any of the preceding claims.

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