MONOSTABLE AND FAULT-TOLERANT PARKING BRAKE VALVE ARRANGEMENT

Description

[0001] The invention relates to a parking brake valve assembly for an electronically controllable pneumatic braking system of a vehicle, in particular a commercial vehicle. The invention further relates to an electronically controllable pneumatic braking system and a vehicle.

[0002] In vehicles, particularly commercial vehicles, with a pneumatic braking system, particularly designed as an electronic braking system (EBS) or anti-lock braking system (ABS), electropneumatic valves, such as electropneumatic switching valves connected upstream of relay valves, can be controlled by a control unit (ECU) to regulate braking pressures. These valves then pneumatically transmit braking pressure to the brake cylinders of the braking system's service brakes depending on a requested vehicle deceleration. Modules in which such units are integrated are often referred to as axle modulators.

[0003] In braking systems for a vehicle combination consisting of a towing vehicle and a trailer, the braking system includes a trailer control unit, also known as a Trailer Control Valve (TCV), which is designed to pneumatically control the target vehicle decelerations specified by the towing vehicle via connections, namely a trailer brake pressure connection and a trailer supply pressure connection, also referred to as the "yellow" and "red" coupling heads. The trailer supply pressure connection supplies the trailer with supply pressure from a designated reservoir on the towing vehicle, while the corresponding brake pressure is controlled via the trailer brake pressure connection.

[0004] As a further component or module, braking systems of the above type have a parking brake unit, also known as an electropneumatic handbrake (EPH). Such parking brake units are usually operated with so-called spring-loaded brakes, i.e. braking devices that brake one or more axles of the towing vehicle based on spring force. When ventilated, the brakes are released, and when vented, they are braked. In a depressurized state, the corresponding vehicle is therefore braked. To activate the parking brake unit, an electrical switch is usually provided in the driver's cab of the towing vehicle, via which a corresponding signal can be output to an electronic control unit, which then switches one or more electropneumatic valves so that the spring-loaded brakes are either vented or ventilated.

[0005] The parking brake unit, i.e. the electro-pneumatic handbrake, is used for parking the vehicle combination but also as an additional brake in special situations. This means that in addition to the normal service brakes, the spring brakes are at least partially vented so that they can be used additionally or alternatively for braking. For example, with pure auxiliary braking, braking is carried out exclusively via spring brakes in the towing vehicle and service brakes in the trailer. The service brakes in the towing vehicle are not activated with pure auxiliary braking. Alternatively, a redundancy mode can be implemented where, for example, in the event of a circuit failure on the rear axle, the spring brakes are used as an alternative to the service brakes. The front axle can still be braked using the service brakes, and the trailer can also be braked using the service brakes.

[0006] The parking brake valve assemblies of the type mentioned above, relating to the invention, are used in such parking brake units or as such parking brake units when the parking brake valve assembly is integrated into a module. Typically, such parking brake valve assemblies operate with a relay valve for volume-amplifying a pilot pressure provided by the pilot unit. A typical parking brake valve assembly, in the form of a parking brake module, is disclosed in DE 10 2012 000 435 A1 by the present applicant. The module disclosed therein has a relay valve that is supplied with a pilot pressure by means of a pilot unit consisting of a 3 / 2-way valve and a 2 / 2-way valve. The relay valve volume-amplifies the pilot pressure and makes it available at a spring-loaded connection to which one or more spring-loaded brake cylinders can be connected.A similar module is disclosed in EP 2 254 779 B1, also by the present applicant. Another example of a similar type is disclosed in DE 10 2007 047 691 A1.

[0007] Other systems are also known, for example, those that include a bistable valve in the pilot control unit. An example of this is disclosed in DE 10 2017 002 715 A1 or DE 10 2017 002 714 A1 by the present applicant.

[0008] There are also integrated approaches that integrate the parking brake unit with a trailer control valve. One such system is known, for example, from DE 10 2017 002 953.

[0009] Furthermore, in modern electronically controllable pneumatic braking systems, which are used particularly in commercial vehicles designed for autonomous driving, it is important to provide measures that still allow the commercial vehicle to decelerate safely in the event of a fault in the braking system. Approaches include the use of fully redundant braking systems, partially redundant braking systems, or simply different levels within a braking system, so that in the event of a fault in a first level, the braking system can continue to operate at least to a limited extent in a second level.

[0010] However, if, for example, a double fault occurs that affects both the primary braking system and the redundant braking system, there is a risk that the commercial vehicle can no longer be braked in a controlled manner. In such cases, there is a need to provide a system that allows the vehicle to decelerate safely.

[0011] A system specifically aimed at achieving high residual availability is known, for example, from DE 10 2014 013 756 B3. This discloses an electrical system for a vehicle with an at least partially electric braking and steering device, which comprises: an electric or electromechanical steering device connected to a steering gear and comprising an electronic steering control device, an electric steering actuator, and a service brake device.DE 10 2014 013 756 B3 proposes an electropneumatic service brake device as a service brake device, which comprises an electropneumatic service brake valve device, an electronic brake control device, electropneumatic modulators, and pneumatic wheel brake actuators. The electronic brake control device electrically controls the electropneumatic modulators to generate pneumatic brake pressures or brake control pressures for the pneumatic wheel brake actuators on a wheel-by-wheel, axle-by-axle, or side-by-side basis. The electropneumatic service brake valve device has a service brake actuating element and, within an electrical service brake circuit, an electrical channel with an electrical brake value transmitter actuated by the service brake actuating element.Furthermore, an electronic evaluation device is provided which receives the actuation signals and, depending on the actuation signals, feeds brake request signals into the electronic brake control device, and comprises at least one pneumatic channel within at least one pneumatic service brake circuit, in which at least one control piston of the service brake valve device is loaded with a first actuation force by actuating the service brake actuating element due to a driver brake request, and the control piston, in response thereto, allows pneumatic brake pressures or brake control pressures to be generated for the pneumatic wheel brake actuators.The electronic evaluation device of the electropneumatic service brake valve device further comprises electronic control means for generating a second actuating force, independent of a driver braking request, which, when a braking request is present that is independent of the driver's intention, acts on the control piston in the same direction or opposite to the first actuating force. The electropneumatic service brake device is powered by an electrical energy source that is independent of a second electrical energy source that supplies the electropneumatic service brake valve device with electrical energy. This ensures that at least one of the two systems functions as always as possible. The electric or electropneumatic steering device is supplied with energy from the second electrical energy source. This is intended to achieve a high residual availability.However, the system is complex and cannot be easily implemented in every commercial vehicle.

[0012] A system that provides electronically pneumatically controlled redundancy is disclosed in DE 10 2016 005 318 A1. The system disclosed therein uses a bypass valve to forward control pressures depending on the failure of a subsystem, thus at least pneumatically supplying the circuit that has failed electrically. This also increases the residual availability. Similar systems are disclosed in DE 10 2016 010 462 A1 and DE 10 2016 010 464 A1.

[0013] Furthermore, DE 10 2016 010 463 A1 discloses a system and method in which pilot valves are electronically controlled via a redundancy signal if a failure or defect is detected in the electronic control of wheel brakes of the braking system. The system attempts to prevent wheels from locking.

[0014] DE 10 2017 002 716, DE 10 2017 002 718, DE 10 2017 002 719, and DE 10 2017 002 721 disclose systems in which pneumatic redundancy is generated. Various controlled brake pressures, such as front axle, rear axle, or trailer brake pressures, are used to provide these as redundancy pressure to failed systems, such as the front axle brake circuit, rear axle brake circuit, parking brake circuit, or trailer brake circuit. This creates a subordinate pneumatic redundancy level, thus also achieving a high level of residual availability.

[0015] In addition, there are also systems that include the trailer, as disclosed, for example, in DE 10 2016 010 461 A1.

[0016] DE 10 2005 024120 A1 discloses a parking brake system for a commercial vehicle, comprising at least one spring-loaded brake cylinder and a first parking brake circuit with a reservoir pressure vessel and a first control valve device that ventilates or de-ventilates the at least one spring-loaded brake cylinder (6). It is provided that, in the event that the first parking brake circuit fails, a further electropneumatic parking brake circuit is provided with a further, separate reservoir pressure vessel and a further control valve device containing at least one solenoid valve, at least for ventilating the spring-loaded brake cylinder in the event of an emergency release, wherein at least the further control valve device is arranged in the immediate vicinity of the at least one spring-loaded brake cylinder.

[0017] Against this background, the object of the invention is to provide a parking brake valve assembly of the type mentioned above that is enhanced in terms of safety. In particular, it is to provide a parking brake valve assembly that does not maintain the released state in the event of serious double faults, but rather provides a solution that allows controlled braking of the vehicle. In this way, the vehicle is to be transferred to a safe state in a controlled manner and secured against rolling away, even in fault situations in which it can no longer be braked electrically, for example, due to a power failure.

[0018] The invention solves the problem with a parking brake valve arrangement of the type mentioned at the outset in that a first compressed air path is provided which receives a first or second supply pressure and has a first monostable valve unit for providing a first parking brake pressure, a second compressed air path is provided which receives the first or the second supply pressure and has a second monostable valve unit for providing a second parking brake pressure, and furthermore a first shuttle valve is provided with a first shuttle valve connection connected to the first compressed air path and receiving the first parking brake pressure, a second shuttle valve connection connected to the second compressed air path and receiving the second parking brake pressure, and a third shuttle valve connection connectable or connected to a spring brake cylinder,wherein the first shuttle valve controls the higher of the first parking brake pressure and the second parking brake pressure at the third shuttle valve port.

[0019] According to the invention, the higher of the first parking brake pressure and the second parking brake pressure is thus delivered to the third shuttle valve connection, which is directly or indirectly connectable to one or more spring brake cylinders. Only this, namely the higher of the two parking brake pressures, is then used to pressurize the correspondingly connected spring brake cylinders. The spring brake cylinder(s) can be directly connected to the third shuttle valve connection, i.e., a volume pressure is delivered directly to the third shuttle valve connection, which is used to pressurize at least one spring brake cylinder.On the other hand, it is also conceivable and preferred that a relay valve is initially connected to the third shuttle valve connection, which then volume-amplified pressure is applied to the pressure received from the third shuttle valve connection and supplies the volume-amplified pressure to one or more spring brake cylinders. The core idea is that the shuttle valve is controlled by two separate, monostable compressed air paths. Each of the first and second compressed air paths is monostable, i.e., it returns to a switched state when de-energized and is not, as is often the case in the prior art, designed to be bistable, i.e. it maintains the switched state even when de-energized. However, as long as one of the first and second compressed air paths supplies a parking brake pressure, namely either the first parking brake pressure or the second parking brake pressure, the spring brake cylinders remain pressed and thus released.Only when both compressed air paths do not supply parking brake pressure are the spring brake cylinders vented and thus applied.

[0020] This arrangement therefore offers the possibility of coupling the first compressed air path, for example, to the first brake circuit, and the second compressed air path, for example, to a second brake circuit, so that the spring-loaded brake cylinders are only engaged if both brake circuits fail. This improves the safety of the vehicle in which the parking brake valve assembly is installed. In the event of a serious double fault in which both the first and second brake circuits fail, i.e. the first and second compressed air paths no longer supply parking brake pressure, the vehicle in which the parking brake valve assembly is installed is automatically braked. It is also possible and preferred to couple the first compressed air path to an operating level of the braking system and the second compressed air path to a redundancy level.In this case, the spring brake cylinders are only engaged when both the operating level and the redundancy level fail.

[0021] The first monostable valve unit is switched by a first electronic control unit, and the second monostable valve unit is switched by a second electronic control unit. The first and second electronic control units are preferably independent of one another. For example, the first electronic control unit is the control unit of a central module, and the second electronic control unit is the control unit of an axle modulator, for example a front-axle or rear-axle modulator. It is also conceivable for the second electronic control unit to be the control unit of an integrated parking brake module. Other control units are also possible. For example, the first electronic control unit is that of a front-axle brake circuit, and the second electronic control unit is that of a rear-axle brake circuit.It is also conceivable and preferred that the first electronic control unit is that of an operating level, while the second electronic control unit is that of a redundancy level.

[0022] Furthermore, it is preferably provided that the first monostable valve unit is supplied by a first voltage source and the second monostable valve unit by a second voltage source. With regard to the first and second voltage sources, the same applies as was described with reference to the first and second electronic control units. In this respect, it is preferred that the first voltage source is assigned, for example, to a front axle brake circuit, and the second voltage source is assigned to a rear axle brake circuit. The first and second voltage sources are preferably independent of one another. It is also conceivable that the first voltage source is assigned to an operating level and the second voltage source to a redundancy level.

[0023] According to a further preferred embodiment, the first monostable valve unit has a first switching valve and a second switching valve, which are pressure-conductingly connected to one another such that the first parking brake pressure is only applied when the first and second switching valves are energized, and the second monostable valve unit has a third switching valve and a fourth switching valve, which are pressure-conductingly connected to one another such that the second parking brake pressure is only applied when the third and fourth switching valves are energized. In this way, safety can be further increased. Even a fault in one of the first and second, or third and fourth switching valves is sufficient to depressurize one of the first and second compressed air paths. At the same time, both valves must be energized in order to be able to apply the corresponding parking brake pressure.This is intended to ensure that the spring-loaded pressure is not activated when one of the valves is switched incorrectly or when a valve is switched incorrectly, but only when corresponding switching signals are provided for the first and second or third and fourth switching valves, i.e. to ensure that the corresponding higher-level control units and / or voltage sources are functional.

[0024] In this case, it is preferably provided that the first switching valve is designed as a first 3 / 2-way valve, the second switching valve as a second 3 / 2-way valve, the third switching valve as a third 3 / 2-way valve, and the fourth switching valve as a fourth 3 / 2-way valve, wherein the first and second 3 / 2-way valves are pneumatically connected in series and the third and fourth 3 / 2-way valves are pneumatically connected in series. This achieves a particularly simple connection, which is designed to be monostable and results in the valves connected in series having to be connected in order to control the first or second parking brake pressure.

[0025] Furthermore, it is preferred that the first switching valve has a first switching valve port receiving the supply pressure, a second switching valve port connected to the second switching valve port, and a third switching valve port connected to a vent. In a first energized switching position, the first switching valve port is connected to the second switching valve port, and in a de-energized second switching position, the second switching valve port is connected to the third switching valve port. The same preferably also applies to the second, third, and fourth switching valves.Accordingly, it is preferably provided that the second switching valve has a fourth switching valve connection connected to the second switching valve connection, a fifth switching valve connection connected to the first shuttle valve connection, and a sixth switching valve connection connected to a vent or the vent. In a first energized switching position, the fourth switching valve connection is connected to the fifth switching valve connection, and in a de-energized second switching position, the fifth switching valve connection is connected to the sixth switching valve connection. Similarly, the following is preferably also provided for the second compressed air path.The third switching valve has a seventh switching valve connection receiving the supply pressure, an eighth switching valve connection connected to the fourth switching valve connection, and a ninth switching valve connection connected to one or the vent, wherein in a first energized switching position the seventh switching valve connection is connected to the eighth switching valve connection, and in a de-energized second switching position the eighth switching valve connection is connected to the ninth switching valve connection.Finally, the fourth switching valve preferably also has a tenth switching valve connection connected to the eighth switching valve, an eleventh switching valve connection connected to the second shuttle valve connection and a twelfth switching valve connection connected to one or the vent, wherein in a first energized switching position the tenth switching valve connection is connected to the eleventh switching valve connection and in a de-energized second switching position the eleventh switching valve connection is connected to the twelfth switching valve connection.

[0026] In a further preferred embodiment, it is provided that the first compressed air path for venting the first shuttle valve connection and the second compressed air path for venting the second shuttle valve connection are each connected to one, in particular a single, vent valve. Via this vent valve, the first or the second shuttle valve connection can then be vented separately from the switching valves, in order to vent the spring brake cylinders connected to the third shuttle valve connection and subsequently brake the vehicle. Preferably, a single vent valve is therefore provided for both the first and the second compressed air path. The vent valve is preferably designed such that it has a non-linear venting characteristic. The vent valve preferably allows venting of the first orsecond shuttle valve connections and thus also the third shuttle valve connection, from a release pressure corresponding to a parking brake pressure sufficient to release the spring brake cylinders connected to the third shuttle valve connection, to a partial brake pressure with a first gradient, and allows venting of the first or second shuttle valve connection from the partial brake pressure to a full brake pressure with a second gradient, wherein the first gradient is greater than the second gradient. If the spring brake cylinders are vented in this way using the vent valve, they are not engaged directly and immediately, but with a non-linear venting characteristic. The non-linear venting characteristic is designed such that the first, second, or third shuttle valve connection is first vented from a release pressure to a partial brake pressure with a first gradient.The release pressure is preferably the minimum pressure required to fully release the spring brake cylinders connected to the third shuttle valve connection. According to this embodiment, venting occurs quickly from this release pressure to the partial brake pressure. The partial brake pressure is preferably designed so that the vehicle is only partially, rather than fully, braked. Braking should therefore be generated without any axles immediately locking. A second gradient is used to vent the system from the partial brake pressure at which partial braking is performed to the full brake pressure at which the spring brake cylinders are correspondingly fully vented and thus fully applied. The second gradient is smaller than the first gradient, so that braking from the partial brake pressure to the full brake pressure occurs more slowly.In this way, it is possible to provide safe deceleration of the vehicle and counteract the risk of immediate axle locking. It is not necessary for the first and second gradients to be constant. Rather, the first and second gradients can also define non-linear venting characteristics. Rather, it is preferred that an average gradient when venting the shuttle valve from the release pressure to the partial brake pressure is greater than an average gradient when venting the shuttle valve from the partial brake pressure to the full brake pressure. Preferably, the first and second gradients are constant. Preferably, the first gradient corresponds to 1.2 times to 100 times, preferably 1.2 times to 20 times the second gradient.

[0027] In a particularly preferred embodiment, the vent valve comprises a pressure limiter and a throttle arranged parallel to the pressure limiter, allowing overflow of the pressure limiter. Two or more pressure limiters and two or more throttles per pressure limiter can also be provided. By providing the pressure limiter and the throttle for overflow of the pressure limiter, it is possible to easily create a non-linear venting characteristic. For example, the venting of the shuttle valve from the release pressure to the partial brake pressure is realized primarily via the pressure limiter, while the venting of the shuttle valve from the partial brake pressure to the full brake pressure is realized primarily via the throttle.

[0028] According to a further preferred embodiment, the parking brake valve assembly further comprises a trailer valve unit for providing a trailer pressure. The trailer pressure can be a trailer parking brake pressure or a reservoir pressure for the trailer, particularly when the parking brake valve assembly is used in a US variant of a braking system. The trailer valve unit is intended to be able to actuate not only the spring brake cylinders of a towing vehicle, but also a trailer at the same time. If the spring brake cylinders of the vehicle are to be engaged via the parking brake valve assembly according to the embodiment described here, they can also be engaged for the trailer via the trailer valve unit. In this case, the trailer is also braked.

[0029] Preferably, the trailer valve unit is connected to the first and second compressed air paths. This allows it to perform the same functions as the shuttle valve.

[0030] It is further preferred that the trailer valve unit receives a first trailer pre-pressure from the first compressed air path and a second trailer pre-pressure from the second compressed air path, and controls the higher of these as the trailer pressure. The pressure controlled via the first and second compressed air paths is thus used not only to actuate the spring brake cylinders of the towing vehicle, but can also be used via the trailer valve unit to brake the trailer.

[0031] In this context, it is preferred that the trailer valve unit comprises a first monostable trailer switching valve connected to the first compressed air path and a second monostable trailer switching valve connected to the second compressed air path. The trailer valve unit is also designed to be monostable and can be controlled in accordance with the monostable first and second compressed air paths.

[0032] Furthermore, it is preferably provided that the first trailer switching valve is designed as a first 3 / 2-way trailer switching valve, and the second trailer switching valve is designed as a second 3 / 2-way trailer switching valve. In this respect, the first and second trailer switching valves are designed to match the switching valves of the first and second monostable valve units. Identical parts can be used here, thus reducing costs.

[0033] Preferably, the first trailer switching valve has a first trailer switching valve connection connected to the second switching valve connection, a second trailer switching valve connection connected to a second shuttle valve, and a third trailer switching valve connection connected to one or the vent. The second trailer switching valve preferably has a fourth trailer switching valve connection connected to the eighth switching valve connection, a fifth trailer switching valve connection connected to a second shuttle valve, and a sixth trailer switching valve connection connected to one or the vent. In this way, the first and second trailer switching valves are connected to the first and second compressed air paths and, in turn, to a second shuttle valve, analogous to the switching valves of the first and second monostable valve units.The higher of the pressure applied is then passed on via the second shuttle valve, in this case specifically to the trailer. In this way, the same functionality that is already provided for the tractor unit is also implemented for the trailer.

[0034] In a second aspect, the object mentioned at the outset is achieved in an electronically controllable pneumatic braking system for a vehicle, in particular a commercial vehicle, having a first electronic control unit and a second electronic control unit, wherein the first and the second electronic control unit are designed such that they can at least partially replace one another in the event of a fault, by a parking brake valve arrangement according to one of the above-described preferred embodiments of a parking brake valve arrangement according to the first aspect of the invention, wherein the first electronic control unit is connected to the first monostable valve unit for providing first switching signals thereto, and the second electronic control unit is connected to the second monostable valve unit for providing second switching signals thereto.It should be understood that the parking brake valve assembly according to the first aspect of the invention and the electronically controllable pneumatic brake system according to the second aspect of the invention have the same and similar sub-aspects, as particularly set forth in the dependent claims. In this respect, reference is made in full to the above description.

[0035] In the event that a trailer valve unit is provided, the electronically controllable pneumatic braking system according to the second aspect of the invention preferably further provides that the first trailer switching valve is controlled by the second electronic control unit and the second trailer switching valve is controlled by the first electronic control unit, and that further switching signals are provided by these, accordingly. This allows cross-connection to be achieved. Alternatively, it is also preferred that the first trailer switching valve is controlled by the first electronic control unit and the second trailer switching valve is controlled by the second electronic control unit.

[0036] In a third aspect, the object mentioned above is achieved by a vehicle, in particular a commercial vehicle, with an electronically controllable pneumatic braking system according to one of the above-described preferred embodiments of an electronically controllable pneumatic braking system according to the second aspect of the invention. It should be understood that the vehicle according to the third aspect of the invention also has the same or similar sub-aspects as the first two aspects of the invention. In this respect, reference is made in full to the above description.

[0037] Embodiments of the invention will now be described below with reference to the drawings. These are not necessarily intended to represent the embodiments to scale; rather, the drawings are schematic and / or slightly distorted where this is useful for explanation. With regard to additions to the teachings immediately apparent from the drawings, reference is made to the relevant prior art. It should be noted that numerous modifications and changes to the form and detail of an embodiment can be made without deviating from the general idea of ​​the invention. The features of the invention disclosed in the description, in the drawings and in the claims can be essential for the further development of the invention, both individually and in any combination.Furthermore, all combinations of at least two of the features disclosed in the description, the drawings and / or the claims fall within the scope of the invention. The general idea of ​​the invention is not limited to the exact form or detail of the preferred embodiments shown and described below, or limited to an object that would be more limited than the object claimed in the claims. For specified dimensioning ranges, values ​​within the stated limits are also intended to be disclosed as limit values ​​and to be used and claimed as desired. For the sake of simplicity, the same reference numerals are used below for identical or similar parts or parts with identical or similar functions.

[0038] Further advantages, features and details of the invention will become apparent from the following description of the preferred embodiments and from the drawings, which show: Fig. 1 shows a first embodiment of a parking brake valve arrangement; Fig. 2 shows a second embodiment of a parking brake valve arrangement; Fig. 3 shows a representation of a non-linear venting characteristic; Fig. 4 shows a third embodiment of a parking brake valve arrangement; and Fig. 5 shows an electronically controllable pneumatic brake system.

[0039] A parking brake valve arrangement 1 (cf. Fig. 1 ) for an electronically controllable pneumatic braking system 210 (cf. Fig. 5 ) of a vehicle 200, in particular commercial vehicle 202, has a first compressed air path 2 and a second compressed air path 4. Both the first and the second compressed air path 2, 4 are supplied with supply pressure pV. It can also be provided that the first compressed air path 2 is supplied with a first supply pressure pV1 and the second compressed air path 4 is supplied with a second supply pressure pV2, as described, for example, with reference to Fig. 5 will be explained in more detail later. A first monostable valve unit 6 is arranged in the first compressed air path 2, and a second monostable valve unit 8 is arranged in the second compressed air path 4. Corresponding pressures can be controlled by switching the first and second monostable valve units 6, 8. Thus, a first parking brake pressure pF1 can be controlled in the first compressed air path 2 by switching the first monostable valve unit 6, and a second parking brake pressure pF2 can be controlled in the second compressed air path 4 by switching the second monostable valve unit 8. The first and second compressed air paths 2, 4 are connected to a first shuttle valve 10, which is designed to control the higher of the first parking brake pressure pF1 and the second parking brake pressure pF2 into a parking brake pressure line 11.The parking brake pressure line 11 can then in turn be connected directly or indirectly to spring brake cylinders 220a, 220b, 220c, 220d, as is basically the case with reference to the . Figuren 4 and 5 shown and will be explained later, below.

[0040] The first shuttle valve 10 is designed as a so-called select-high valve and has a first shuttle valve connection 10.1 which is connected to the first compressed air path 2 for receiving the first parking brake pressure pF1, a second shuttle valve connection 10.2 which is connected to the second compressed air path 4 for receiving the second parking brake pressure pF2 and a third shuttle valve connection 10.3 which is designed to control the higher of the first and second parking brake pressures pF1, pF2 and is connected to the parking brake pressure line 11 for this purpose.

[0041] The first monostable valve unit 6 in this embodiment comprises a first switching valve 12 and a second switching valve 14. Both switching valves 12, 14 are monostable and each operate without current in the Fig. 1 shown first switching position, in which they vent the first compressed air path 2 and thus also the first shuttle valve connection 10.1. More precisely, the first switching valve 12 is designed as a first 3 / 2-way valve 13. The first switching valve 12 has a first switching valve connection 12.1, which receives supply pressure pV, or the first supply pressure pV1, a second switching valve connection 12.2, and a third switching valve connection 12.3, which is connected to a vent 7. The second switching valve connection 12.2 is connected to the second switching valve 14. The second switching valve 14 is designed as a second 3 / 2-way valve 15. The second switching valve 14 has a fourth switching valve connection 14.1, which is connected to the second switching valve connection 12.2 and receives the pressure controlled by the latter, a fifth switching valve connection 14.2 and a sixth switching valve connection 14.3, which in turn is connected to one or the vent 7.The fifth switching valve connection 14.2 is in the position shown in . Fig. 1 In the embodiment shown, the fifth switching valve connection 14.2 is connected directly to the first shuttle valve connection 10.1 via a corresponding line. However, it can also be provided that additional elements are present there, so that the fifth switching valve connection 14.2 is only indirectly connected to the first shuttle valve connection 10.1. The first and second switching valves 12, 14 are pneumatically connected in series.

[0042] Both switching valves, the first and the second switching valve 12, 14, are connected to a first electronic control unit ECU1, which provides a first switching signal S1 to them. This means that the first and second switching valves 12, 14 are switched together and receive the same first switching signal S1. In the first de-energized switching position of the first switching valve 12, the second switching valve connection 12.2 is connected to the third switching valve connection 12.3, so that the supply pressure pV cannot be controlled by the first switching valve 12. Only when the first switching valve 12 is de-energized by the Fig. 1 shown first switching position to the one shown in Fig. 1 not shown second switching position, in which the first switching valve connection 12.1 is connected to the second switching valve connection 12.2, the supply pressure pV can be controlled from the first switching valve connection 12.1 to the second switching valve connection 12.2 and accordingly made available to the fourth switching valve connection 14.1. However, if the second switching valve 14 is also in the first in Fig. 1 shown currentless switching position, no pressure is again output at the first shuttle valve connection 10.1, since the fourth switching valve connection 14.1 is closed and rather the fifth switching valve connection 14.2 is connected to the sixth switching valve connection 14.3, so that the first shuttle valve connection 10.1 is connected via the second switching valve 14 to one or the vent 7. Only when the second switching valve 14 is also in the Fig. 1 second switching position (not shown), and thus the fourth switching valve connection 14.1 is connected to the fifth switching valve connection 14.2, the pressure output by the first switching valve 12 is forwarded through the second switching valve 14 and output as the first parking brake pressure pF1 at the first shuttle valve connection 10.1. This means that both the first and the second switching valves 12, 14 must be switched in order to output the first parking brake pressure pF1 at the first shuttle valve connection 10.1.

[0043] The second compressed air path 4 is constructed in an analogous manner, so that what was said above with reference to the first compressed air path 2 applies accordingly.

[0044] Both switching valves in the second compressed air path 4 in the second monostable valve unit 8, the third and fourth switching valves 16, 18, are connected to a second electronic control unit ECU2, which provides them with a second switching signal S2. This means that the third and fourth switching valves 16, 18 are switched together and receive the same second switching signal S2. In the first de-energized switching position of the third switching valve 16, the eighth switching valve connection 16.2 is connected to the ninth switching valve connection 16.3, so that the supply pressure pV cannot be controlled by the third switching valve 16. Only when the third switching valve 16 is Fig. 1 shown first switching position to the one shown in Fig. 1 not shown second switching position, in which the seventh switching valve connection 16.1 is connected to the eighth switching valve connection 16.2, the supply pressure pV can be controlled from the seventh switching valve connection 16.1 to the eighth switching valve connection 16.2 and accordingly made available to the tenth switching valve connection 18.1. However, if the fourth switching valve 18 is also in the first in Fig. 1 shown currentless switching position, no pressure is output at the second shuttle valve connection 10.2, since the tenth switching valve connection 18.1 is closed and rather the eleventh switching valve connection 18.2 is connected to the twelfth switching valve connection 18.3, so that the second shuttle valve connection 10.2 is connected via the fourth switching valve 18 to one or the vent 7. Only when the fourth switching valve 18 is also in the Fig. 1 second switching position (not shown), and thus the tenth switching valve connection 18.1 is connected to the eleventh switching valve connection 18.2, the pressure output by the third switching valve 16 is forwarded through the fourth switching valve 18 and output as the second parking brake pressure pF2 at the second shuttle valve connection 10.2. This means that both the third and fourth switching valves 16, 18 must be switched in order to output the second parking brake pressure pF2 at the second shuttle valve connection 10.2.

[0045] The first electronic control unit ECU1 and the second electronic control unit ECU2 are preferably independent of one another and, for example, assigned to two different modules within the electronically controllable pneumatic brake system 210. Preferably, the first electronic control unit ECU1 is supplied by a first voltage source Q1, and the second electronic control unit ECU2 is supplied by a second voltage source Q2. The first and second voltage sources Q1, Q2 are also preferably independent of one another.

[0046] In this way, it can be ensured that, as long as one of the first and second electronic control units ECU1, ECU2, or one of the first and second voltage sources Q1, Q2 is functioning properly, at least one of the first and second parking brake pressures pF1, pF2 is activated, so that at the third shuttle valve connection 10.3, when one of the two electronic control units ECU1, ECU2 is functioning properly, a parking brake pressure pF1, pF2 is activated, so that in this case the spring brake cylinders 220a to 220d remain released. Only when both the first electronic control unit ECU1, or first voltage source Q1 and the second electronic control unit ECU2, orIf the second voltage source Q2 fails and thus both the first and the second switching signal S2 are no longer provided or are no longer provided correctly, both the first and the second compressed air path 2, 4 are vented and subsequently the spring brake cylinders 220a to 220d are also vented and the vehicle 200 is braked.

[0047] Fig. 2 now illustrates a second embodiment of the parking brake valve arrangement 1, wherein the same and similar elements are given the same reference numerals as in Fig. 1 In this respect, reference is made in full to the above description. In particular, the differences to the first embodiment ( Fig. 1 ) is highlighted.

[0048] The significant difference in the second embodiment compared to the first embodiment ( Fig. 1 ) is that a vent valve 20 is provided.

[0049] The vent valve 20 is in the Fig. 2 The embodiment shown is formed from a pressure limiter 22 with a throttle 24 arranged parallel thereto, which allows overflow of the pressure limiter 22. The pressure limiter 22 itself is then in turn connected to a vent 7.

[0050] The combination in the vent valve 20 with pressure limiter 22 and throttle 24 allows a non-linear venting characteristic E (cf. Fig. 3 ). In the event that a fault occurs in the electronically controllable pneumatic brake system 210 and, as a result, the first and second electronic control units ECU1, ECU2 fail, so that the first and second switching signals S1, S2 are no longer provided, the first and second compressed air paths 2, 4 are connected to the vent valve 20 via the second switching valve 14 and the third switching valve 18 and are thus vented. The pressure limiter 22 then initially allows venting to a partial brake pressure pLT with a gradient G1 (cf. Fig. 3 ) and, as soon as the limit pressure, in this case the partial brake pressure pLT, is reached, a remaining venting of the first and second shuttle valve connections 10.1, 10.2 down to a full brake pressure pLV, which can preferably correspond to the ambient pressure, is realized via the throttle 24, this being done with a second gradient G2.

[0051] As can be seen in particular from Fig. 3 As can be seen, the first gradient G1 is significantly greater than the second gradient G2. At the time t1, at which both the first and second electronic control units ECU1, ECU2 fail, and the first and second switching signals S1, S2 are no longer provided, the third shuttle valve port 10.3 is vented with the first gradient G1, whereby the pressure drops from the first or second parking brake pressure pF1, pF2, which may correspond to the reservoir pressure pV, to the partial brake pressure pLT. Once this is reached (time t2), the pressure drops from the partial brake pressure pLT to the full brake pressure pLV with the second gradient G2. The full brake pressure pLV is only reached at time t3. As can easily be seen from Fig. 3 As can be seen from the graph, the interval between the second time t2 and the third time t3 is significantly longer than the interval between the first time t1 and the second time t2, namely approximately 15.5 times as long. Fig. 3 The first gradient G1 is approximately 20 times as large as the second gradient G2, whereby the first gradient G1 is also non-linear and the second gradient G2 is essentially linear. Rather, the first gradient G1 is formed according to an exponential function, whereby the average value of the first gradient G1 is in the Fig. 3 shown example is approximately 4.2. Other sizes and ratios are also preferred, such as a factor of 10 or greater. It is important that the pressure is rapidly released from the first or second parking brake pressure pF1, pF2 to the partial brake pressure pLT in order to quickly achieve partial braking and thus partial deceleration of the vehicle 200, but then slowly released from the partial brake pressure pLT to the full brake pressure pLV in order to prevent locking of the VA and HA axles and uncontrolled deceleration of the vehicle 200.

[0052] In the Figuren 1 and 2First and second pressure sensors 26, 28 can also be seen. The first pressure sensor 26 is arranged between the second switching valve 14 and the first shuttle valve 10 and thus detects the first parking brake pressure pF1, which is controlled by the second switching valve 14. The second pressure sensor 28 is arranged between the fourth switching valve 18 and the first shuttle valve 10 and thus detects the second parking brake pressure pF2, which is controlled by the fourth switching valve 18. The first pressure sensor 26 provides a first pressure signal SP1 to the first electronic control unit ECU1, and the second pressure sensor 28 provides a second pressure signal SP2 to the second electronic control unit ECU2. In this way, the first and second electronic control units ECU1, ECU2 can determine whether the first and second switching valves 12, 14 and the third and fourth switching valves 16, 18 are functioning correctly and, when the first and fourth switching valves 12, 14 are controlled,second switching signals S1, S2 actually control the first or second parking brake pressure pF1, pF2.

[0053] Fig. 4 illustrates a third embodiment of the parking brake valve arrangement 1. Again, the same and similar elements are given the same reference numerals as in the first two embodiments ( Fig. 1 , Fig. 2 ), so that reference is made in full to the above description. The following also describes in particular the differences to the first two embodiments ( Fig. 1 , Fig. 2 ) is explained.

[0054] The key difference in the third embodiment ( Fig. 4 ) with respect to the first embodiment ( Fig. 1 ) is that a trailer valve unit 30 is provided. The trailer valve unit 30 serves to control a trailer pressure pA, which can then be made available to a trailer (not shown) connected to it via a trailer control valve 212. This is intended to brake the trailer in accordance with the towing vehicle. Since some trailers do not have spring-loaded brake cylinders, but must be actively braked by a positive brake pressure, it may be necessary to provide an inverter in the trailer control valve 212. However, these embodiments are generally known and will not be discussed in more detail below.

[0055] The trailer valve unit 30 is designed according to the Fig. 4 shown third embodiment is integrated into the parking brake valve arrangement 1. In principle, it should be understood that this does not require a complete duplication of the valves of the first and second embodiments ( Fig. 1 , Fig. 2 ) is required, but only six switching valves are used, thus saving two valves compared to a complete duplication. For this purpose, the trailer valve unit 30 is also integrated into the first and second compressed air paths 2, 4.

[0056] Specifically, the first and third switching valves 12, 16 are used as common switching valves for both the parking brake pressure pF1, pF2 and the trailer pressure pA. Between the first and second switching valves 12, 14 in the first compressed air path 2, a first trailer pilot line 40 branches off, leading to a first monostable trailer switching valve 32. Similarly, between the third and fourth switching valves 16, 18, a second trailer pilot line branches off, leading to a second monostable trailer switching valve 34. The first monostable trailer switching valve 32 is thus assigned to the first compressed air path 2, and the second monostable trailer switching valve 34 is assigned to the second compressed air path 4.

[0057] The first monostable trailer switching valve therefore receives the pressure controlled by the first switching valve 12 when this is switched from the first in Fig. 4 shown switching position to the second, in Fig. 4 not shown, switching position. If the first monostable trailer switching valve 32 is also switched from the first to Fig. 4 shown switching position to the second, in Fig. 4 not shown, switching position, this controls a pressure which is then provided to a second shuttle valve 36. In an analogous manner, the second monostable trailer switching valve 34 receives the pressure controlled by the third switching valve 16 and, when the second monostable trailer switching valve 34 is in the second, in Fig.4 not shown, switching position, it controls this pressure received from the third switching valve 16 at the second shuttle valve 36. The second shuttle valve 36 then in turn controls the higher of the first and second trailer pre-pressure pAV1, pAV2 as the trailer pressure pA.

[0058] More precisely, the first monostable trailer switching valve 32 is designed as a first 3 / 2-way trailer switching valve 33. It has a first trailer switching valve connection 32.1, which is connected to the first trailer pilot line 40, a second trailer switching valve connection 32.2, which is connected to the second shuttle valve 36, more precisely to a fourth shuttle valve connection 36.1, and a third trailer switching valve connection 32.3, which is connected to one or the vent 7. In the Fig. 4 In the first de-energized switching position shown, the first monostable trailer switching valve 32 connects the second trailer switching valve connection 32.2 with the third trailer switching valve connection 32.3, so that the fourth shuttle valve connection 36.1 is vented. In the second, in Fig. 4 not shown switching position, the first trailer switching valve connection 32.1 is connected to the second trailer switching valve connection 32.2, so that the first trailer pre-pressure pAV1 is controlled.

[0059] In an analogous manner, the second monostable trailer switching valve 34 is designed as a second 3 / 2-way trailer switching valve 35. It has a fourth trailer switching valve connection 34.1, which is connected to the second trailer pilot line 32. In addition, it has a fifth trailer switching valve connection 34.2, which is connected to the second shuttle valve 36, more precisely to a fifth shuttle valve connection 36.2, as well as a sixth trailer switching valve connection 34.3, which is connected to one or the vent 7. Again, in the first Fig. 4 In the de-energized switching position of the second monostable trailer switching valve 34 shown, the fifth trailer switching valve connection 34.2 is connected to the sixth trailer switching valve connection 34.3, so that the fifth shuttle valve connection 36.2 is vented. In the second, in Fig. 4 In the switching position of the second monostable trailer switching valve 34 (not shown), the fourth trailer switching valve connection 34.1 is connected to the fifth trailer switching valve connection 34.2, so that the second trailer pre-pressure pAV2 is output at the fifth shuttle valve connection 36.2. The second shuttle valve 36 then outputs the higher of the first trailer pre-pressure pAV1, which is present at the fourth shuttle valve connection 36.1, and the second trailer pre-pressure pAV2, which is present at the fifth shuttle valve connection 36.2, to a sixth shuttle valve connection 36.3, namely as trailer pressure pA.

[0060] The first and second monostable trailer switching valves 32, 34 are also connected to the first and second electronic control units ECU1, ECU2 in accordance with the first and second monostable valve units 6, 8. Thus, the first monostable trailer switching valve 32, which is associated with the first compressed air path 2, is also controlled by the first electronic control unit ECU1 and switched by the first switching signal S1. Similarly, the second monostable trailer switching valve 34, which is associated with the second compressed air path 4, is controlled by the second electronic control unit ECU2, specifically by means of the second switching signal S2. Fig. 4 There is another special feature that will be described below.

[0061] Third and fourth shuttle valves 44, 46 are pneumatically connected downstream of the first shuttle valve 10. More precisely, the third shuttle valve connection 10.3, to which the higher of the first and second parking brake pressures pF1, pF2 is controlled, is connected via a T-piece 34 both to a seventh shuttle valve connection 44.1 of the third shuttle valve 44 and to a tenth shuttle valve connection 46.1 of the fourth shuttle valve 46. The third shuttle valve 44 further has an eighth shuttle valve connection 44.2 and a ninth shuttle valve connection 44.3. The third shuttle valve is designed as a select-high valve and controls the higher pressure present at the seventh and eighth shuttle valve connections 44.1, 44.2 to the ninth shuttle valve connection 44.3. The ninth shuttle valve connection 44.3 is connected to the spring brake cylinder 220a in order to pressurize or vent it.

[0062] Analogously, the fourth shuttle valve has, in addition to the tenth shuttle valve connection 46.1, an eleventh shuttle valve connection 46.2 and a twelfth shuttle valve connection 46.3. The fourth shuttle valve 46 is configured to control the higher of the pressure applied to the tenth and eleventh shuttle valve connections 46.1, 46.2 at the twelfth shuttle valve connection 46.3. The twelfth shuttle valve connection 46.3 is connected to a spring-loaded brake cylinder 220b for venting or venting the brake.

[0063] The eighth shuttle valve connection 44.2 and the eleventh shuttle valve connection 46.2 are in turn connected to a parking brake relay valve 48, which is fed by the first and second supply pressures pV1, pV2 and receives a parking brake control pressure pSP as control pressure. The parking brake control pressure pSP is provided by another unit, such as a parking brake switch, a parking brake module, or the like, and is described with reference to Fig. 5 provided by a rear axle relay valve 214 to pressurize and thus release the spring brake cylinders 220a, 220d during normal driving operation. The spring brake cylinders 220a to 220d can also be used for additional braking or actuated by an anti-compound function via the rear axle relay valve 214. This allows the first or second parking brake pressure pF1, pF2 output by the parking brake valve assembly 1 to be overridden in order to pressurize and thus release the spring brake cylinders 220a to 220d, if necessary, in the event that the parking brake valve assembly 1 is not functioning or is not functioning properly, or the vehicle 200 is in a de-energized, parked state.

[0064] Fig. 5 now illustrates an electronically controllable pneumatic braking system 210 for a vehicle 200, wherein the vehicle 200 is designed as a commercial vehicle 202 and has a front axle VA as well as a rear axle HA and a second rear axle HA2. As can be seen from the comparison of the Figuren 4 and 5 As can be seen, the parking brake valve arrangement 1 according to a third embodiment ( Fig. 4 ) in the electronically controllable pneumatic braking system 210 according to Fig. 5 implemented. Identical and similar elements are again provided with the same reference numerals, so that full reference is made to the above description.

[0065] The electronically controllable pneumatic braking system 210 has a central module 222, which is connected to an autonomous driving unit 226 via a vehicle bus 224. The central module 224 is supplied by the first voltage source Q1.

[0066] Furthermore, the electronically controllable pneumatic braking system 210 has a first primary modulator 228, which is provided for controlling the front axle VA and comprises the first electronic control unit ECU1, and a second primary modulator 230, which is provided for controlling the rear axle and comprises the second electronic control unit ECU2. Both the first and second primary modulators 228, 230 are connected to the autonomous driving unit 226 via the vehicle bus 224 and receive electronic braking request signals SB from the autonomous driving unit 226, which are converted by the autonomous driving unit to control a front axle brake pressure pBVA and a rear axle brake pressure pBHA. For this purpose, the first primary modulator 228 receives the first supply pressure pV1 from the first compressed air supply 3, and the second primary modulator 230 receives the second supply pressure pV2 from a second compressed air supply 5.The first primary modulator 228 is connected to the first voltage source Q1, and the second primary modulator 230 is connected to the second voltage source Q2. The first primary modulator 228 also pneumatically controls a front axle relay valve 232, while the second primary modulator 230 pneumatically controls the rear axle relay valve 214. The front axle relay valve 232 and rear axle relay valve 214 do not have any intelligence of their own.

[0067] To provide a level of redundancy, a first secondary modulator 234 and a second secondary modulator 236 are also provided, which in turn receive first and second supply pressures pV1, pV2, respectively. The first and second secondary modulators 234, 236 are pneumatically designed, with electromagnetically switchable valves (not shown), but without their own intelligence. They are pneumatically connected to a brake value transmitter BST, which supplies corresponding pressures to the first and second secondary modulators 234, 236, which can then be converted by the first and second secondary modulators 236, 234. The first and second secondary modulators 234, 236 are pneumatically connected to the first and second primary modulators 228, 230 in order to pneumatically control the first and second primary modulators 228, 230 in the event of redundancy, i.e., if the first and / or second primary modulators 228, 230 fail.The corresponding electromagnetic switching valves in the first and second secondary modulators 234, 236 are each controlled crosswise, i.e., the first secondary modulator 234, which is pneumatically connected to the first primary modulator 228 for controlling the front axle VA, receives electrical switching signals for its electromagnetically switchable valves from the second primary modulator 230 in the event that the first primary modulator 228 fails. The second secondary modulator 236, which is pneumatically connected to the second primary modulator 230 for controlling the rear axle(s) HA, HA2, receives switching signals for its electromagnetically switchable valves from the first primary modulator 228 in the event that the second primary modulator 230 fails.

[0068] In the event that both the first and the second primary modulator 228, 230 fail, no first and second switching signals S1, S2 are output in the above-described form, so that consequently the first and second parking brake pressure pF1, pF2 are no longer output and possibly also the trailer pressure pA is no longer output. As a result, the spring brake cylinders 220a to 220d of the vehicle 200 are vented and thus applied and, if necessary, the trailer is braked. In this way, further redundancy is introduced in the event that both the first primary modulator 228 and the second primary modulator 230 fail. In this case, the vehicle 200 can still be braked in a controlled manner, preferably with the reference to Fig. 3 described nonlinear venting characteristic E. List of reference symbols (part of the description)

[0069] 1 Parking brake valve arrangement 2 First compressed air path 3 First compressed air supply 4 Second compressed air path 5 Second compressed air supply 6 First monostable valve unit 7 Bleed 8 Second monostable valve unit 10 First shuttle valve 10.1 First shuttle valve connection 10.2 Second shuttle valve connection 10.3 Third shuttle valve connection 11 Parking brake pressure line 12 First switching valve 12.1 First switching valve connection 12.2 Second switching valve connection 12.3 Third switching valve connection 13 First 3 / 2-way valve 14 Second switching valve 14.1 Fourth switching valve connection 14.2 Fifth switching valve connection 14.3 Sixth switching valve connection 15 Second 3 / 2-way valve 16 Third switching valve 16.1 Seventh switching valve connection 16.2 Eighth switching valve connection 16.3 Ninth switching valve connection 17 Third 3 / 2-way valve 18 Fourth switching valve 18.1 Tenth switching valve connection 18.2 Eleventh switching valve connection 18.3 Twelfth switching valve connection 19 Fourth 3 / 2-way valve 20 Vent valve 22 Pressure limiter24 Throttle 26 First pressure sensor 28 Second pressure sensor 30 Trailer valve unit 32 First monostable trailer switching valve 32.1 First trailer switching valve connection 32.2 Second trailer switching valve connection 32.3 Third trailer switching valve connection 33 First 3 / 2-way trailer switching valve 34 Second monostable trailer switching valve 34.1 Fourth trailer switching valve connection 34.2 Fifth trailer switching valve connection 34.3 Sixth trailer switching valve connection 35 Second 3 / 2-way trailer switching valve 36 Second shuttle valve 36.1 Fourth shuttle valve connection 36.2 Fifth shuttle valve connection 36.3 Sixth shuttle valve connection 40 First trailer pilot line 42 Second trailer pilot line 43 T-piece 44 Third shuttle valve 44.1 Seventh shuttle valve connection 44.2 Eighth shuttle valve connection 44.3 Ninth shuttle valve connection 46 Fourth shuttle valve 46.1 Tenth shuttle valve connection 46.2 Eleventh shuttle valve connection 46.3 Twelfth shuttle valve connection 48 Parking brake relay valve 200 Vehicle202 Commercial vehicle 210 Electronically controllable pneumatic braking system 212 Trailer control valve 214 Rear axle relay valve 220a, 220b, 220c, 220d Spring brake cylinder 222 Central module 224 Vehicle bus 226 Autonomous driving unit 228 First primary modulator 230 Second primary modulator 232 Front axle relay valve 234 First secondary modulator 236 Second secondary modulator BST Brake value sensor E Bleeding characteristic ECU1 First electronic control unit ECU2 Second electronic control unit G1 First gradient G2 First gradient pATrailer pressure pAV1 First trailer pre-pressure pAV2 Second trailer pre-pressure pF1 First parking brake pressure pF2 Second parking brake pressure pLT Partial brake pressure pLV Full brake pressure pSP Parking brake control pressure pV Supply pressure pV1first supply pressure pV2second supply pressure Q1first voltage source Q2second voltage source S1first switching signal S2second switching signal SBelectronic brake request signal SP1first pressure signal SP2second pressure signal VAfront axle HArear axle

Claims

1. Parking brake valve assembly (1) for an electronically controllable pneumatic brake system (210) of a vehicle (200), in particular a commercial vehicle (202), comprising: a first compressed air path (2) receiving a first or second supply pressure (pV, pV1, pV2) and having a first monostable valve unit (6) for providing a first parking brake pressure (pF1), a second compressed air path (4) receiving the first or the second supply pressure (pV, pV1, pV2) and having a second monostable valve unit (8) for providing a second parking brake pressure (pF2), and a first shuttle valve (10) having a first shuttle valve connection (10.1) with the first compressed air path (2) and receiving the first parking brake pressure (pF1), a second shuttle valve connection (10.2) with the second compressed air path (4) and receiving the second parking brake pressure (pF2), and a third shuttle valve connection (10.3) which can be connected to a spring-loaded brake cylinder (220a, 220b, 220c, 220d), wherein the first shuttle valve (10) outputs the higher of the first parking brake pressure (pF1) and the second parking brake pressure (pF2) at the third shuttle valve connection (10.3), characterized in that the first monostable valve unit (6) is switched by a first electronic control unit (ECU1) and the second monostable valve unit (8) is switched by a second electronic control unit (ECU2).

2. Parking brake valve assembly (1) according to claim 1, wherein the first monostable valve unit (6) is supplied by a first voltage source (Q1) and the second monostable valve unit (8) is supplied by a second voltage source (Q2).

3. Parking brake valve assembly (1) according to any one of the preceding claims, wherein the first monostable valve unit (6) comprises a first switching valve (12) and a second switching valve (14) which are connected to one another in a pressure-conducting manner such that the first parking brake pressure (pF1) is output only when the first and the second switching valve (12, 14) are energized, and the second monostable valve unit (8) comprises a third switching valve (16) and a fourth switching valve (18) which are connected to one another in a pressure-conducting manner such that the second parking brake pressure (pF2) is output only when the third and fourth switching valve (16, 18) are energized.

4. Parking brake valve assembly (1) according to claim 3, wherein the first switching valve (12) is designed as a first 3 / 2-way valve (13), the second switching valve (14) is designed as a second 3 / 2-way valve (15), the third switching valve (16) is designed as a third 3 / 2-way valve (17) and the fourth switching valve (18) is designed as a fourth 3 / 2-way valve (19), wherein the first and the second 3 / 2-way valve (13, 15) are pneumatically connected in series and the third and fourth 3 / 2-way valve (17, 19) are pneumatically connected in series.

5. Parking brake valve assembly (1) according to claim 3 or 4, wherein the first switching valve (12) comprises a first switching valve connection (12.1) which receives the supply pressure (pV, pV1, pV2), a second switching valve connection (12.2) which is connected to the second switching valve (14), and a third switching valve connection (12.3) which is connected to a vent (7), wherein, in a first energized switching position, the first switching valve connection (12.1) is connected to the second switching valve connection (12.2) and, in a de-energized second switching position, the second switching valve connection (12.2) is connected to the third switching valve connection (12.3); the second switching valve (14) comprises a fourth switching valve connection (14.1) which is connected to the second switching valve connection (12.2) of the first switching valve (12), a fifth switching valve connection (14.2) which is connected to the first shuttle valve connection (10.1), and a sixth switching valve connection (14.3) which is connected to a or the vent (7), wherein, in a first energized switching position, the fourth switching valve connection (14.1) is connected to the fifth switching valve connection (14.2) and, in a de-energized second switching position, the fifth switching valve connection (14.2) is connected to the sixth switching valve connection (14.3); the third switching valve (16) comprises a seventh switching valve connection (16.1) which receives the supply pressure (pV, pV1, pV2), an eighth switching valve connection (16.2) which is connected to the fourth switching valve (18) and a ninth switching valve connection (16.3) which is connected to a or the vent (7), wherein, in a first energized switching position, the seventh switching valve connection (16.1) is connected to the eighth switching valve connection (16.2) and, in a de-energized second switching position, the eighth switching valve connection (16.2) is connected to the ninth switching valve connection (16.3); the fourth switching valve (18) comprises a tenth switching valve connection (18.1) which is connected to the eighth switching valve connection (16.2) of the third switching valve (16), an eleventh switching valve connection (18.2) which is connected to the second shuttle valve connection (10.2) and a twelfth switching valve connection (18.3) which is connected to a or the vent (7), wherein, in a first energized switching position, the tenth switching valve connection (18.1) is connected to the eleventh switching valve connection (18.2) and, in a de-energized second switching position, the eleventh switching valve connection (18.2) is connected to the twelfth switching valve connection (18.3).

6. Parking brake valve assembly (1) according to any one of the preceding claims, wherein the first compressed air path (6) for venting the first shuttle valve connection (10.1) and the second compressed air path (8) for venting the second shuttle valve connection (10.2) are each connected to one, in particular a single, vent valve (20).

7. Parking brake valve assembly (1) according to claim 6, wherein the vent valve (20) comprises a pressure limiter (22) and a throttle (24) which is arranged parallel to the pressure limiter (22) and allows overflow of the pressure limiter (22).

8. Parking brake valve assembly (1) according to any one of the preceding claims, further comprising a trailer valve unit (30) for providing a trailer pressure (pA).

9. Parking brake valve assembly (1) according to claim 8, wherein the trailer valve unit (30) is connected to the first and the second compressed air path (2, 4).

10. Parking brake valve assembly (1) according to claim 9, wherein the trailer valve unit (30) receives a first trailer pre-pressure (pAV1) from the first compressed air path (2) and a second trailer pre-pressure (pAV2) from the second compressed air path (4), and outputs the higher of the first or second trailer pre-pressure (pAV1, pAV2) as the trailer pressure (pA).

11. Parking brake valve assembly (1) according to any one of claims 8 to 10, wherein the trailer valve unit (30) comprises a first monostable trailer switching valve (32) connected to the first compressed air path (2), and a second monostable trailer switching valve (34) connected to the second compressed air path (4).

12. Parking brake valve assembly (1) according to claim 11, wherein the first monostable trailer switching valve (32) is designed as a first 3 / 2-way trailer switching valve (33), and the second monostable trailer switching valve (34) is designed as a second 3 / 2-way trailer switching valve (35).

13. Parking brake valve assembly (1) according to claim 5 and any one of claims 11 or 12, wherein the first monostable trailer switching valve (32) comprises a first trailer switching valve connection (32.1) which is connected to the second switching valve connection (12.2), a second trailer switching valve connection (32.2) which is connected to a second shuttle valve (36), and a third trailer switching valve connection (32.3) which is connected to a or the vent (7), and the second monostable trailer switching valve (34) comprises a fourth trailer switching valve connection (34.1) which is connected to the eighth switching valve connection (16.2), a fifth trailer switching valve connection (34.2) which is connected to the second shuttle valve (36), and a sixth trailer switching valve connection (34.3) which is connected to a or the vent (7).

14. Electronically controllable pneumatic brake system (210) for a vehicle (200), in particular a commercial vehicle (202), comprising a first electronic control unit (ECU1) and a second electronic control unit (ECU2), wherein the first and the second electronic control unit (ECU1, ECU2) are designed in such a way that they can at least partially replace one another in the event of a fault, and a parking brake valve assembly (1) according to any one of claims 1 to 13, wherein the first electronic control unit (ECU1) is connected to the first monostable valve unit (6) for providing first switching signals (S1) thereto, and the second electronic control unit (ECU2) is connected to the second monostable valve unit (8) for providing second switching signals (S2) to the second monostable valve unit (8).

15. Vehicle (200), in particular a commercial vehicle (202), comprising an electronically controllable pneumatic brake system (210) according to claim 14.