Electropneumatic parking brake device with parallel venting paths

Abstract

The invention relates to a parking brake device for supplying and venting air in spring brake cylinders (254c, 254d, 254e, 254f), comprising a parking brake valve unit (2) and a parking brake redundancy unit (10) which is designed to connect a parking brake compressed air path (12) to a vent (14) in order to vent air from at least one spring brake cylinder (254c, 254d, 254e, 254f) independently of the parking brake valve unit (2), wherein the parking brake redundancy unit (2) comprises a first venting path (18) and a parallel second venting path (30) for directly venting pressure (pFS, pV) of the parking brake compressed air path (12) into the surroundings. A first redundancy valve unit (22) is provided in the first venting path (18) and can be actuated by a first control unit (26), and a second redundancy valve unit (24) is provided in the second venting path (30) and can be actuated by a second control unit (28) which is independent of the first control unit (26). The invention additionally relates to a brake system (200) and to a vehicle (300).

Description

[0001] Electropneumatic parking brake device with parallel venting paths

[0002] The invention relates to an electropneumatic parking brake device for pressurizing and venting one or more spring-loaded brake cylinders of an at least partially electronically controllable pneumatic braking system for a vehicle, comprising an electropneumatic parking brake valve unit with a supply connection for receiving supply pressure from a compressed air supply, and a parking brake control unit, wherein the parking brake valve unit is configured to control a parking pressure at at least one spring-loaded connection depending on a parking brake signal. The invention further relates to an electronically controllable pneumatic braking system and a vehicle comprising such a braking system.

[0003] Modern commercial vehicles often feature an electronically controlled pneumatic braking system. The braking system typically includes spring-loaded parking brakes, also known as parking brakes. Parking brakes operate under spring force and can be released or engaged by applying a parking pressure to spring-loaded brake cylinders. To regulate service brake pressure, valves within a service brake system are electronically controlled. The valves can be located inside or outside axle modulators. The axle modulators can be automated or semi-automated and / or electronically controlled by an autonomous unit. The parking brakes are also electronically controlled. For example, the actuation of a solenoid valve can control the actuation or venting of the spring-loaded brake cylinders.The spring-loaded brake cylinders can be combined with service brake cylinders so that the spring-loaded brake and service brake act on the same brake pistons. Suitable design measures can be taken to prevent mechanical overloading of the brake pistons due to the addition of braking forces from the service brakes and the spring-loaded brakes. If the service brakes are applied while the parking brakes are active, the spring-loaded brake cylinders are vented at the same time to prevent the braking forces from adding up. This function is also known as an "anti-compound function." The parking brake must be engageable by the vehicle driver. In some markets, this is achieved by an electronic parking brake request to the parking brake system. In other markets, venting of the spring-loaded brake cylinders is provided for safety reasons if the reservoir pressure in the service brake system drops.The service brake and parking brake can also be assigned to different brake circuits.

[0004] Safety concepts are highly relevant for electropneumatic braking systems in modern vehicles. Especially in vehicles with automated or partially automated driving functions, braking functions must remain available, at least to a limited extent, even in the event of a fault or a power failure of a control unit. This is the only way to guarantee the safety of the vehicle, its occupants, and other road users. For this purpose, it is known to provide redundancy levels that can still provide at least a limited braking function even if a primary system fails.

[0005] In addition to the service brakes, a redundancy level is also desired for the parking brake, since in most cases vehicles can only be parked safely with the parking brake engaged. To expand functionality and, in particular, to be able to ventilate and thus release the corresponding spring-loaded cylinders of the parking brake regardless of the occurrence of a fault on one of the various levels, be it the operating level or a redundancy level of the braking system, it is desirable for the spring-loaded brake cylinders to be able to be controlled via two independent paths. This is intended to increase the range of functions and operational readiness of the vehicle. By providing a redundancy level, safe parking of the vehicle can be guaranteed even in the event of one or more faults in the braking system.

[0006] From DE 102021 122 497 A1 a method for operating an electropneumatic braking system for a vehicle is known, wherein the braking system comprises a service braking system and a parking braking system, wherein the parking braking system comprises at least one spring-loaded brake cylinder.The method is characterized by the following steps: providing a control signal for maintaining a spring-loaded brake pressure that vents the at least one spring-loaded brake cylinder by a control unit; interrupting the provision of the control signal in the event of a fault and / or a power failure and / or a diagnostic event of the control unit, thereby automatically terminating the maintenance of the spring-loaded brake pressure to vent the at least one spring-loaded brake cylinder; thereby triggering a spring-loaded brake failure of the vehicle by the parking brake system, wherein the venting of the spring-loaded brake pressure is performed by a service brake venting function of the service brake system. The service brake venting function enables at least one venting path, in particular one that is open continuously or intermittently, in the service brake system for venting the at least one spring-loaded brake cylinder.The service brake venting function is implemented in particular by a valve in the service brake system, preferably an outlet valve and / or another outlet valve.

[0007] Further partially redundant systems are known from DE 102022 101 142 A1 , DE 10 2021 122 498 A1 , DE 102021 122 499 A1 , DE 102020 132 875 A1 and EP 3 145 769 B1.

[0008] Even though existing systems already provide a partially redundant option for engaging or releasing a parking brake, there is still room for further improvements. In particular, the aforementioned known options can be complex to assemble and manufacture, as the connection to the service brake system may require long cable runs. Furthermore, the achievable system dynamics may be limited.

[0009] It is therefore desirable to improve the engagement of a parking brake. In particular, the venting of at least one spring brake cylinder should be possible reliably and with minimal effort.

[0010] This is where the invention comes in. Its object is to provide an improved electropneumatic parking brake device that enables the simple and / or reliable venting of a spring-loaded brake cylinder, even in the case of redundancy. In a first aspect, the invention solves this problem with an electropneumatic parking brake device according to claim 1.Starting from an electropneumatic parking brake device of the type mentioned above, an electropneumatic parking brake redundancy unit is further provided, which is designed to connect a parking compressed air path to a vent, independently of the electropneumatic parking brake valve unit, for venting at least one spring brake cylinder. The parking brake redundancy unit comprises at least a first main connection for receiving a pressure from the parking compressed air path, a first vent path for directly venting the pressure to the environment, and a second vent path for directly venting the pressure to the environment. A first electropneumatic redundancy valve unit of the electropneumatic parking brake redundancy unit is arranged in the first vent path and can be controlled by a first control unit.A second electropneumatic redundancy valve unit of the electropneumatic parking brake redundancy unit is arranged in the second venting path and can be controlled by a second control unit. The second control unit is independent of the first control unit. The first venting path and the second venting path are parallel venting paths for directly venting the pressure received from the parking brake compressed air path to the environment.

[0011] Typically, the electropneumatic parking brake valve unit is designed to pressurize and vent spring-loaded brake cylinders. According to the invention, the parking brake redundancy unit is also provided to vent a spring-loaded brake cylinder of the braking system and thus engage the parking brake. For this purpose, the parking brake valve unit can connect a parking compressed air path to a vent, whereby this connection can be made independently of the electropneumatic parking brake valve unit. Thus, a spring-loaded brake cylinder can be vented even if the electropneumatic parking brake valve unit is faulty, is not supplied with power, or is otherwise restricted in its function. The parking compressed air path is a compressed air path assigned to the vehicle's parking brake. This can be a compressed air path directly connected to one or more spring-loaded brake cylinders.For example, the parking compressed air path can be a compressed air path between the spring-loaded connection of the parking brake valve unit and the spring-loaded brake cylinder. However, it can also be provided, for example and preferably, that the parking compressed air path is a supply path that connects a compressed air supply of the brake system to the parking brake and / or that is provided for supplying a service brake circuit.

[0012] The parking brake redundancy unit comprises at least a first venting path and a second venting path. The first venting path connects a main connection of the parking brake redundancy unit to a first redundancy vent into the environment. The second venting path connects a main connection to a second redundancy vent. The first redundancy vent and the second redundancy vent open directly into the environment. Therefore, no further functional units of a brake system are provided between the respective redundancy vent and the environment. However, it can be provided that the first and / or second redundancy vent comprises one or more passive elements, such as a silencer and / or a line. In particular, no switchable components or modulators are arranged between the redundancy vent and the environment.The direct connection of the redundant vent to the environment eliminates further sources of error. Furthermore, high system dynamics can be achieved. Furthermore, line lengths can be reduced, which can reduce the assembly and manufacturing effort for the parking brake device. The main connection of the second vent path can be the main connection to which the first vent path is also connected. Preferably, the second redundant vent of the second vent path is different from the first redundant vent of the first vent path. However, the first redundant vent and the second redundant vent can also be formed by a common redundant vent. In this case, the parallel vent paths then flow into the same redundant vent.However, it should be understood that the first venting path and the second venting path can in principle also be connected to more than two main connections and / or redundant vents.

[0013] Preferably, the first venting path and the second venting path are parallel to a primary venting path of the parking brake valve unit. The primary venting path connects the spring-loaded connection of the parking brake valve unit to a primary vent of the parking brake valve unit. The first venting path of the parking brake redundancy unit, the second venting path of the parking brake redundancy unit, and the primary venting path of the parking brake valve unit are preferably connected to one another at the spring-loaded connection. However, in a possible alternative, it can also be provided that the first venting path, the second venting path, and the primary venting path open into a connecting line to the spring-loaded brake cylinder. In other variants, the first venting path, the second venting path, and / or the primary venting path are completely separate.

[0014] The first electropneumatic redundancy valve unit can be controlled by a first control unit, and the second electropneumatic redundancy valve unit can be controlled by a second control unit. The control units can be control units of the parking brake system, but do not have to be.

[0015] Preferably, the first control unit and / or the second control unit is a service brake control unit of a braking system. The second control unit is independent of the first control unit. This can further increase the reliability of the parking brake system, since if one of the control units fails, the other control unit can continue to function.

[0016] In a first preferred development of the electropneumatic parking brake device, the first redundancy valve unit has a first electrically switchable vent valve, which is arranged in the first vent path and is designed to interrupt the first vent path in a de-energized state, and the second redundancy valve unit has a second electrically switchable vent valve, which is arranged in the second vent path and is designed to interrupt the second vent path in a de-energized state. The first electrically switchable vent valve is preferably pre-tensioned to a closed state and returns to this when it is de-energized. Analogously, the second electrically switchable vent valve is preferably also pre-tensioned to a closed state. The first control unit can control the first vent valve by energizing or de-energizing it.Supplying electrical energy to an open state in which the first vent valve releases the first vent path. The second vent valve can be controlled analogously by the second control unit and can be energized or supplied with electrical energy by it. By such control, the second vent valve can be brought into an open state in which it releases the second vent path. By providing two parallel vent paths, the main connection and an associated locking compressed air path can still be vented even if one of the two control units has a fault and accordingly the first vent valve or the second vent valve can no longer be switched to the open state.

[0017] The first redundancy valve unit preferably has a third electrically switchable vent valve arranged in the second vent path. Alternatively or additionally, the second redundancy valve unit preferably comprises a fourth electrically switchable vent valve arranged in the first vent path. In a particularly preferred embodiment, the first redundancy valve unit and the second redundancy valve unit each comprise at least one vent valve in the first vent path and in the second vent path. This allows each of the control units to act on both vent paths. Operational reliability can thus be further increased if necessary.

[0018] Preferably, the third vent valve is open in a de-energized state and / or the fourth vent valve is open in a de-energized state. In the open state, the third vent valve releases the second vent path. Similarly, the fourth vent valve releases the first vent path in a de-energized state.

[0019] This prevents the third vent valve from blocking the second vent path in the event of a fault in the first control unit. The main connection can then still be vented via the second vent path even if the first control unit fails. The same applies to the fourth vent valve and the first vent path.

[0020] The third vent valve can be controlled by the first control unit. The first control unit can switch the third vent valve to a closed state and thus block the second vent path. Analogously, the second control unit can switch the fourth vent valve to a closed state and block the first vent path. This allows, in particular, increased safety in the event that one of the control units has a fault and unintentionally opens the associated compressed air path. For example, the first control unit can switch the third vent valve to the closed state if the second control unit has a fault and switches the second vent valve to an open state, even though this is not desired in the current driving situation. Operational safety can thus be further increased.

[0021] In a preferred embodiment, the electropneumatic parking brake device comprises a first pressure sensor for detecting a first pressure of the first venting path, wherein the first pressure sensor is designed to provide first pressure signals corresponding to the detected first pressure to the first control unit. Alternatively or additionally, the electropneumatic parking brake device can also comprise a second pressure sensor for detecting a second pressure of the second venting path, wherein the second pressure sensor is designed to provide second pressure signals corresponding to the detected second pressure to the second control unit. Particularly preferably, the electropneumatic parking brake device comprises the first pressure sensor and the second pressure sensor.

[0022] In a preferred embodiment, the first pressure sensor is arranged upstream of the first vent valve. Based on the first pressure signals, the first control unit can thus determine whether or not a pressure to be vented, for example a locking pressure, is present at the inlet of the first vent valve. The second pressure sensor can be arranged upstream of the second vent valve in a similar manner. It should be understood that the arrangement of the valves and pressure sensors relates to their functional arrangement. A pressure sensor arranged upstream of a valve is designed to detect a pressure upstream of this valve, but can also be arranged physically remotely therefrom. For example, the first pressure sensor can be connected by a measuring line to a section of the first vent path upstream of the first vent valve.Particularly preferably, the first pressure sensor is arranged between the first vent valve and the fourth vent valve. Preferably, the fourth vent valve is arranged upstream of the first vent valve, i.e., closer to the main connection.

[0023] The second pressure sensor is preferably arranged between the second vent valve and the third vent valve. The electropneumatic parking brake device preferably comprises at least one connection pressure sensor for detecting a pressure present at the main connection. The connection pressure sensor is preferably designed to provide connection pressure signals corresponding to the pressure present at the main connection to a control unit. The connection pressure sensor is preferably connectable to the first control unit and / or the second control unit. A control unit connected to the connection pressure sensor can, for example, use the connection pressure signals to determine whether or not spring-loaded pressure is present at the main connection or whether a spring-loaded brake cylinder connected to the main connection via the parking compressed air path is ventilated or vented. In further developments, multiple connection pressure sensors can also be provided.

[0024] Preferably, the first electrically switchable vent valve and the second electrically switchable vent valve are 2 / 2-way valves, in particular solenoid valves.

[0025] In a second aspect, the invention solves the aforementioned problem with an electronically controllable pneumatic braking system for a vehicle, comprising at least one first front axle brake actuator and one second front axle brake actuator for a front axle of the vehicle, and at least one first rear axle brake actuator and one second rear axle brake actuator for a rear axle of the vehicle. The braking system further comprises a primary system with a primary control unit at least for controlling the first front axle brake actuator and the second front axle brake actuator and / or for controlling the first rear axle brake actuator and the second rear axle brake actuator, and an electropneumatic parking brake device according to one of the preferred embodiments described above according to the first aspect of the invention.The at least one spring-loaded connection of the electropneumatic parking brake valve unit is preferably connected to at least one first spring-loaded brake cylinder. The primary system is preferably a service brake system of the vehicle. The primary control unit is typically independent of the parking brake control unit. The electropneumatic parking brake valve unit of the parking brake device is designed to ventilate a parking brake cylinder connected to the spring-loaded connection (releasing the parking brake). Furthermore, the parking brake valve unit is preferably designed to vent the parking brake cylinder connected to the spring-loaded connection. This is preferably done by corresponding signals from the parking brake control unit. The parking brake valve unit therefore typically serves as the primary device for engaging and releasing the vehicle's parking brake.The parking brake redundancy unit preferably provides redundancy for the parking brake valve unit and allows the parking brake to be engaged even if the parking brake valve unit, in particular the parking brake control unit, is faulty. However, it should be understood that the main connection of the parking brake redundancy unit does not need to be connected to the spring brake cylinder for this purpose.

[0026] In a first preferred embodiment of the brake system, however, at least the first spring brake cylinder is connected to the main connection of the

[0027] Parking brake redundancy unit connected. The parking brake redundancy unit is preferably switchable to connect the spring brake cylinder to the environment via the first venting path, via the second venting path, or via the first venting path and the second venting path in order to vent the spring brake cylinder. In this case, the parking compressed air path is therefore a compressed air path connected to at least one spring brake cylinder. When venting via the first venting path and the second venting path, a particularly large flow cross-section can be used to vent the compressed air path, and the parking brake can be applied particularly quickly.

[0028] In an alternative embodiment of the electronically controllable pneumatic brake system, the main connection is connected to at least a first compressed air supply of the brake system. The parking brake redundancy unit is switchable to connect the compressed air supply to the environment via the first venting path, the second venting path, or via the first venting path and the second venting path in order to vent at least the first compressed air supply. In this variant, the parking compressed air path is therefore a compressed air path connected to a first compressed air supply. The parking brake redundancy unit can connect the compressed air supply to the redundancy vent and thus cause a pressure drop in a supply compressed air path of the brake system. This can then cause the parking brake to be engaged.For example, braking systems for the North American market typically feature a so-called push-pull valve that automatically engages the parking brake as soon as the supply pressure or reservoir pressure falls below a predefined level. Here, too, highly dynamic performance can be achieved by using both venting paths for venting.

[0029] Preferably, the primary control unit is or includes the first control unit. The primary control unit can then control the first electropneumatic redundancy valve unit. Since the primary control unit and the parking brake control unit are typically independent units, the primary control unit can thus form a redundancy level for the parking brake control unit. This is particularly advantageous because an existing control unit can be used as a redundancy level. However, it can also be provided that the first control unit is a separate control unit.

[0030] In a preferred development of the above-described embodiments, the electronically controllable pneumatic brake system further comprises a secondary system with a secondary control unit, wherein the secondary system is designed to control the first front axle brake actuator and the second front axle brake actuator and / or the first rear axle brake actuator and the second rear axle brake actuator. Preferably, the secondary system is designed to control the first front axle brake actuator and the second front axle brake actuator and / or the first rear axle brake actuator and the second rear axle brake actuator if a fault is detected in the primary system. The secondary system then preferably forms a redundancy level for the primary system, which is provided in particular in vehicles with a high degree of automation. The secondary system can therefore also be a redundant service brake system.

[0031] Preferably, the secondary control unit is or includes the second control unit. In this preferred variant, an existing control unit can also be used as a backup for the parking brake control unit.

[0032] In a preferred variant, the electronically controllable pneumatic brake system has a first voltage source and a second voltage source, wherein the first voltage source is provided for supplying the first control unit with electrical voltage, and wherein the second voltage source is provided for supplying the second control unit with electrical voltage. Providing mutually independent voltage sources can further increase the reliability of the brake system, since a failure of a single voltage source does not cause a total failure of the parking brake system. The parking brake control unit can be connected to the first voltage source or to the second voltage source for supplying electrical voltage.

[0033] According to a third aspect of the invention, the object mentioned at the outset is achieved by a commercial vehicle having at least one front axle, at least one first rear axle and 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.

[0034] It should be understood that the electronically controllable pneumatic braking system according to the second aspect of the invention as well as the commercial vehicle according to the third aspect of the invention have the same and similar sub-aspects as are particularly set out in the dependent claims to the first aspect of the invention and to the second aspect of the invention.

[0035] 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.

[0036] 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:

[0037] Fig. 1 is a schematic representation of a commercial vehicle with an electronically controllable pneumatic braking system;

[0038] Fig. 2 is a schematic representation of a first embodiment of a parking brake device; and in

[0039] Fig. 3 is a schematic representation of a second embodiment of a parking brake device.

[0040] Fig. 1 shows an electronically controllable pneumatic braking system 200 with an electropneumatic parking brake device 1. The electronically controllable pneumatic braking system 200 is used in a vehicle 300 designed as a commercial vehicle 302, which is shown here highly schematically, in particular with a front axle VA, a first rear axle HA1 and a second rear axle HA2.

[0041] The electronically controllable pneumatic braking system 200 here has first, second, third, fourth, fifth, and sixth service brake actuators 208a-208f, each for a wheel of the vehicle 300. A rear axle brake circuit 202 and a front axle brake circuit 204 are provided to supply the first to sixth service brake actuators 208a-208f with brake pressure. The service brake actuators 208a, 208b are assigned to the front axle VA and are therefore also referred to as front axle brake actuators 208a, 208b. Similarly, the service brake actuators 208c-208f assigned to the rear axles HA1, HA2 are also referred to as rear axle brake actuators 208c-208f. The rear axle brake circuit 202 is supplied by a first compressed air supply 206 and the front axle brake circuit 204 is supplied by a second compressed air supply 210.The commercial vehicle 300 is designed here as a towing vehicle and comprises a trailer brake circuit 207 with a trailer module 209, which is provided for supplying a trailer (not shown) connected to the commercial vehicle 300 with compressed air.

[0042] The electronically controllable pneumatic braking system 200 has an operating level and a first redundancy level. At the operating level, the electronically controllable pneumatic braking system 200 comprises a primary system 212 with an electronic primary control unit 214, which controls the electronically controllable pneumatic braking system 200 at the operating level. The electronic primary control unit 214 is connected to an autonomous driving unit 218 via a vehicle bus 216 and receives braking request signals SA from it. Furthermore, the electronic primary control unit 214 is connected to a first voltage source 222 via a first supply line 220 and is supplied with electrical energy therefrom. The electronic primary control unit 214 converts the braking request signals SA and, based thereon, controls operating braking signals SB at a first operating axle modulator 224.The first operating axle modulator 224 here is a front axle modulator 228 provided for the front axle VA. Alternatively or additionally, brake request signals SA can also be provided by an electronic foot brake pedal 264 on the primary control unit 214.

[0043] The first service axle modulator 224 is connected to the second compressed air supply 210 and receives supply pressure pV therefrom. Based on the received service brake signals SB, the first service axle modulator 224 controls a first service brake pressure pB1 at a first service brake pressure connection 232.1 and a second service brake connection 232.2. At the first and second service brake pressure connections 232.1, 232.2, the first service brake pressure pB1 is preferably controlled in a wheel-specific manner, and the first service axle modulator 224 is designed as a two-channel modulator. In other embodiments, the first service brake pressure connection 232.1 and the second service brake pressure connection 232.2 can also be combined, and the first service axle modulator 224 can thus be designed as a single-channel axle modulator that controls the first service brake pressure pB1 in a wheel-specific manner.

[0044] A first wheel speed sensor 234 is also provided on the front axle VA, which provides first wheel speed signals SD to the primary control unit 214. The primary control unit 214 is configured to process the first wheel speed signals SD and provide ABS switching signals to ABS valves 238 of the front axle VA in order to achieve slip control or ABS modulation of the first service brake pressure pB1 and prevent locking of the front wheels of the vehicle 300.

[0045] Furthermore, the electronically controllable pneumatic braking system 200 comprises, at the operating level, a second operating axle modulator 236, which is provided for the first and second rear axles HA1, HA2 and can thus also be referred to as a rear axle modulator 237. In the exemplary embodiment shown in Fig. 1, the rear axle modulator 237 is installed with the electronic primary control unit 214 to form a module, which is referred to here as the central module 240. However, it should be understood that the rear axle modulator 237 and the primary control unit 214 can also be separate or structurally separated. The primary control unit 214 and the rear axle modulator 237 can then be connected to one another, for example, via a signal line or a bus line.Internally, the primary electronic control unit 214 controls the rear axle modulator 237 in accordance with the braking request signals SA that the primary control unit 214 has received from the autonomous driving unit 218.

[0046] A supply port 230 of the second operating axis modulator 236 is connected to the first compressed air supply 206 and receives supply pressure pV therefrom.

[0047] According to its control by the primary control unit 214, the rear axle modulator 237 controls at least a second service brake pressure pB2; in the exemplary embodiment shown here, however, it also controls a third service brake pressure pB3. In the exemplary embodiment shown in Fig. 1, the second service brake pressure pB2 is provided for the right side of the vehicle, and the third service brake pressure pB3 is provided for the left side of the vehicle. The rear axle modulator 237 is therefore designed here as a two-channel axle modulator. The second service brake pressure pB2 is intended for a fourth and sixth service brake actuator 208d, 208f, while the third service brake pressure pB3 is provided for a third and a fifth service brake actuator 208c, 208e. In other variants, the first service axle modulator 236 can also be designed as a single-channel modulator or as a multi-channel modulator with more than two outputs.

[0048] At the redundancy level, the electronically controllable pneumatic braking system 200 includes a secondary control unit 242 of a secondary system 241, which is designed to control the electronically controllable pneumatic braking system 200 in the event of one or more errors at the operating level. The secondary control unit 242 can thus control the electronically controllable pneumatic braking system 200, for example, in the event of a power failure in the first voltage source 222, an electronic error in the primary control unit 214, or the like.

[0049] The electronic secondary control unit 242 is also connected to the autonomous driving unit 218 via the vehicle bus 216 and also receives braking request signals SA from it. Unlike the primary control unit 214, the secondary control unit 242 is connected to a second voltage source 246 via a second supply line 244 and is supplied with electrical energy from it. The first and second voltage sources 222, 246 are independent of one another, so that a failure in the first voltage source 222 does not lead to a loss of the second voltage source 246, and vice versa. The electronic primary control unit 214 and the electronic secondary control unit 242 are therefore electrically independent of one another.

[0050] In order to exchange signals, the primary control unit 214 and the secondary control unit 242 are connected to one another via a redundancy bus 248. In this way, the secondary control unit 242 can determine the availability of the primary control unit 214 and only assume control of the electronically controllable pneumatic braking system 200 when the primary control unit 214 is not available or is no longer available correctly. However, in variants, communication between the primary control unit 214 and the secondary control unit 242 can also take place, for example, via the vehicle bus 216. A redundancy axle modulator 250 is provided in the redundancy level, which is connected to the secondary control unit 242 and receives redundancy braking signals SR from it. In the exemplary embodiment according to Fig. 1, the secondary control unit 242 is integrated into the redundancy axle modulator 250.In other variants, the secondary control unit 242 and the redundant axis modulator 250 may also be physically separate units.

[0051] The redundant axis modulator 250 is connected to the second compressed air supply 210, which is independent of the first compressed air supply 206, so that the second compressed air supply 210 can provide supply pressure pV even if the first compressed air supply 206 fails. In other embodiments, the redundant axis modulator 250 can also be connected to the second compressed air supply 210 or to the first compressed air supply 206 and the second compressed air supply 210.

[0052] The redundancy axle modulator 250 controls a redundancy brake pressure pBR1 at a redundancy brake pressure connection 252 depending on the redundancy brake signals SR. The redundancy brake pressure pBR1 controlled at the redundancy brake pressure connection 252 is provided to the front axle modulator 228. The redundancy axle modulator 250 is shown in Fig. 1 as a single-channel axle modulator with only one redundancy brake pressure connection 252, but can also be designed as a multi-channel axle modulator, which can, for example, implement a side-by-side control of redundancy brake pressures.

[0053] The secondary control unit 242 can control the redundant axle modulator 250 such that, in the event of a fault in the primary control unit 214, a brake pressure, namely the redundant brake pressure pBR1, is still provided to the front axle brake actuators 208a, 208b. Unlike what is shown in Fig. 1, the redundancy level can also be provided for braking the first and second rear axles HA1, HA2. This can be achieved by means of the redundant axle modulator 250 or by means of a second redundant axle modulator. The secondary control unit 242 can then preferably also be provided for controlling such a second redundant axle modulator. The brake actuators assigned to the wheels of the rear axles HA1, HA2 are designed here as double-acting brake actuators, also referred to as tri-stop cylinders. In addition to the service brake actuators 208c-208f, these each include a spring brake cylinder 254c-254f.The spring-loaded brake cylinders 254c-254f are designed to apply the brakes of the vehicle 300 when they are depressurized or vented. The spring-loaded brake cylinders 254c-254f can thus be advantageously used as a parking brake, which does not require compressed air to brake the rear axles HA1, HA2. To release the rear wheels, the spring-loaded brake cylinders 254c-254f must be pressurized with a parking pressure pFS. This parking pressure pFS counteracts the spring brake and releases the brakes of the vehicle 300.

[0054] To provide the parking brake function, the braking system 200 comprises the electropneumatic parking brake device 1. This comprises an electropneumatic parking brake valve unit 2, which is supplied with supply pressure pV via a supply connection 4. In the illustrated embodiment, the supply connection 4 is connected to the first compressed air supply 206. Here, the parking brake valve unit 2 is additionally supplied with supply pressure pV from the second compressed air supply 210. In other variants, the electropneumatic parking brake valve unit 2 can alternatively or additionally be connected to a third compressed air supply, which is preferably independent of the first compressed air supply 206 and the second compressed air supply 210.It should be understood that the electropneumatic parking brake valve unit 2 can be supplied only from the first compressed air supply 206, only from the second compressed air supply 210, only from the third compressed air supply 206, from at least two compressed air supplies or from the first compressed air supply 206, from the second compressed air supply 210 and from the third compressed air supply.

[0055] The electropneumatic parking brake valve unit 2 comprises a parking brake control unit 6, which is connected to the autonomous driving unit 218 via the vehicle bus 216. To engage the parking brake, the autonomous driving unit 218 provides a parking brake signal SFS to the parking brake control unit 6 via the vehicle bus 216, which then provides the parking brake pressure pFS at a first spring-loaded connection 8a and a second spring-loaded connection 8b. In Fig. 1, the first spring-loaded connection 8a is connected to the spring-loaded brake cylinders 254d, 254f, and the second spring-loaded connection 8b is connected to the spring-loaded brake cylinders 254c, 254e. By providing the parking brake pressure pFS, the electropneumatic parking brake valve unit 2 pressurizes the spring-loaded brake cylinders 254c-254f, thus releasing the parking brake.To engage the parking brake of vehicle 300, the electropneumatic parking brake valve unit 2 can vent the spring-loaded brake ports 8a, 8b or the associated spring-loaded brake cylinders 254c-254f. This can occur in response to the receipt of corresponding second parking brake signals at the parking brake control unit 6 or when no more parking brake signals SFS are provided by the parking brake control unit 6.

[0056] To provide redundancy for the electropneumatic parking brake valve unit 2, the electropneumatic parking brake device 1 further comprises an electropneumatic parking brake redundancy unit 10. The parking brake redundancy unit 10 is designed to vent at least one of the spring brake cylinders 254c-254f independently of the electropneumatic parking brake valve unit 2. This can be done directly or indirectly. Thus, as shown in the exemplary embodiment according to Fig. 1, the parking brake redundancy unit 10 can vent a parking compressed air path 12, which is directly connected to the spring brake cylinders 254c-254f, directly to the environment. In alternative variants, the parking compressed air path 12 can also be connected to the first compressed air supply 206 and / or the second compressed air supply 210.Furthermore, the parking compressed air path 12 can alternatively or additionally also be connected to a third compressed air supply, which is not shown in Fig. 1. The parking brake redundancy unit 10 then connects this to the first.

[0057] The parking brake compressed air path 12 connected to the compressed air supply 206, the second compressed air supply 210, or a third compressed air supply is connected to the environment in order to vent the spring brake cylinders 254c-254f. The connection to the environment is established via one or more redundancy vents 14, 15 of the electropneumatic parking brake redundancy unit 10. The parking brake redundancy unit 10 can therefore be used to vent only one compressed air supply 206, 210 or to vent two, three, four, or more compressed air supplies 206, 210. The parking brake redundancy unit 10 comprises a main connection 16, which is provided for connection to the parking compressed air path 12. In Fig. 1, the spring brake cylinders 254c-254f are directly connected to the main port 16 and the spring brake ports 8a, 8b. In Fig.1, the parking brake redundancy unit 10 receives the parking pressure pFS at the main connection 16 if the parking brake of the vehicle 300 is released or the spring brake cylinders 254c-254f are ventilated.

[0058] The electropneumatic parking brake redundancy unit 10 is designed to connect the main connection 16 to a redundancy vent 14, 15. For this purpose, the electropneumatic parking brake redundancy unit 10 comprises a first vent path 18 and a second vent path 30. The first vent path 18 and the second vent path 30 are vent paths 18, 30 of the electropneumatic parking brake redundancy unit 10 that are at least partially parallel to one another. In the exemplary embodiment according to Fig. 1, the first vent path 18 runs from the main connection 16 via a first electropneumatic redundancy valve unit 22 to a first redundancy vent 14, where it discharges into the environment. The second venting path 30 of the electropneumatic parking brake redundancy unit 10 runs parallel to the first venting path 18 from the main connection 16 to a second redundancy vent 15 and opens into the environment there.In other variants, however, the electropneumatic parking brake redundancy unit 10 could, for example, have two main connections 16. In variants, the first venting path 16 and the second venting path 30 can also have a common redundant vent 14, 15.

[0059] The parking pressure air path 12 connects the spring-loaded connections 8a, 8b of the electropneumatic parking brake valve unit 2 with the spring-loaded brake cylinders 254c, 254d, 254e, 254f. If the electropneumatic parking brake valve unit 2 experiences a fault and can no longer vent the spring-loaded pressure pFS present in the parking pressure air path 12 to engage the parking brake, the electropneumatic parking brake redundancy unit 10 forms a redundancy. The parking pressure pFS present in the parking compressed air path 12 for venting the spring brake cylinders 254c, 254d, 254e, 254f is also present at the main connection 16 of the electro-pneumatic parking brake redundancy unit 10 and can be vented to the environment via the first venting path 18, the second venting path 30 or both via the first venting path 18 and the second venting path 30 in order to engage the parking brake of the vehicle 300.Even if venting via the electropneumatic parking brake valve unit 2 should no longer be possible due to a fault, the parking brake cylinders 254c-254f can be connected to the environment via the first venting path 18 or via the second venting path 30 and thus vented.

[0060] Fig. 1 schematically shows the arrangement of the first electropneumatic redundancy valve unit 22 in the first venting path 18 and the second electropneumatic redundancy valve unit 24 in the second venting path 30. However, it should be understood that subcomponents of the first electropneumatic redundancy valve unit 22 can also be arranged in the second venting path 30 and / or that subcomponents of the second electropneumatic redundancy valve unit 24 can also be arranged in the first venting path 18. The first redundancy valve unit 22 can be controlled by a first control unit 26, which in the illustrated embodiment is the primary control unit 214. For this purpose, the first redundancy valve unit 22 is connected to the primary control unit 214 via a first redundancy signal line 256. The second redundancy valve unit 24 can be controlled in an analogous manner by a second control unit 28, which here is formed by the secondary control unit 242.The connection between the secondary control unit 242 and the second redundancy valve unit 24 is made via a second redundancy signal line 258. The primary control unit 214 and the secondary control unit 242 are independent of one another and are supplied by separate voltage sources 222, 246, so that by using the primary control unit 214 as the first control unit 26 and the secondary control unit 242 as the second control unit 28, a redundancy level with high reliability can be created in a particularly simple manner.

[0061] In the embodiment shown in Fig. 1, both the first control unit 26 and the second control unit 28 are independent of the parking brake control unit 6. In other embodiments, however, the parking brake control unit 6 can, for example, also form or comprise the first control unit 26 or the second control unit 28. Fig. 2 now schematically shows a first embodiment of the electropneumatic parking brake device 1, wherein, for the sake of simplicity, the first rear axle HA1 with the associated parking brake cylinders 254c, 254d is also shown. The electropneumatic parking brake valve unit 2 is shown schematically, wherein the spring-loaded connections 8a, 8b are shown here in a simplified manner as a common spring-loaded connection 8.The main connection 16 is also shown only in a highly simplified manner and opens into the parking compressed air path 12, which here is a connecting line between the spring-loaded connection 8 of the parking brake valve unit 2 and the spring-loaded brake cylinders 254c, 254d.

[0062] In the first embodiment, the first venting path 18 and the second venting path 30 of the electropneumatic parking brake redundancy unit 10 are connected to the main connection 16. Downstream of the main connection 16, the venting paths 18, 20 branch off at a schematically illustrated node 32.

[0063] The first vent path 18 runs from the node 32 to a first electrically switchable vent valve 34 of the first electropneumatic redundancy valve unit 22. In the first exemplary embodiment shown in Fig. 2, the first electrically switchable vent valve 34 is an electrically switchable 2 / 2-way valve. An inlet connection 34.1 of the first electrically switchable vent valve 34 is directly connected to the node 32 and the main connection 16 arranged upstream of the node 32. A first outlet connection 34.2 of the first electrically switchable vent valve 34 is directly connected to the first redundancy vent 14. In variants, however, a further line can also be provided between the first outlet connection 34.2 and the first redundancy vent 14.

[0064] In the first exemplary embodiment, the first electrically switchable vent valve 34 is designed as a solenoid valve. The first control unit 26 is adapted to control the first electrically switchable vent valve 34 of the first electropneumatic redundant valve unit 22. Here, the control unit 26 can energize a first magnet 34.3 of the first electrically switchable vent valve 34 in order to switch the first electrically switchable vent valve 34 from a closed switching position shown in Fig. 2 to an open switching position. In the open switching position, the first inlet port 34.1 and the first outlet port 34.2 of the first electrically switchable vent valve 34 are fluidically connected, so that the first electrically switchable vent valve 34 releases the first vent path 18 in the open switching position.The parking pressure pFS of the parking compressed air path 12 present at the main connection 16 can then be vented directly to the environment via the first venting path 18 and the first redundant venting 14. As a result, the spring brake cylinders 254c, 254d are also vented via the parking compressed air path 12, and the parking brake is engaged.

[0065] In the closed switching position, the first electrically switchable vent valve 34 interrupts the connection between the first inlet port 34.1 and the first outlet port 34.2. In the first exemplary embodiment, and preferably, the first electrically switchable vent valve 34 is monostable and preloaded into the closed position. If the first control unit 26 no longer controls the first electrically switchable vent valve 34 or, in this case, no longer supplies the first magnet 34.3 with electrical energy, the first electrically switchable vent valve 34 automatically returns to the closed switching position. This prevents the first vent path 18 from being opened in the event of a fault in the first control unit 26.

[0066] In an analogous manner, the second venting path 30 comprises a second electrically switchable venting valve 36. This second electrically switchable venting valve 36 is essentially identical to the first electrically switchable venting valve 34. The second venting path 30 runs from the main connection 16 via the node 32, a second inlet connection 36.1 of the first electrically switchable venting valve 36 to a second outlet connection

[0067] 36.2 of the electrically switchable vent valve 36 and the second redundant vent 15 directly connected thereto. Here, too, however, a further line could be provided, for example, between the second outlet connection 36.2 and the second redundant vent 15. Furthermore, the second outlet connection 36.2 could also be connected to the first redundant vent 14.

[0068] The second control unit 28 is configured to switch the second electrically switchable vent valve 36 from a closed position to an open position, thus releasing the second vent path 30. The parking pressure pFS can then flow along the second vent path 30 from the main port 16 to the second redundant vent 15, thereby venting the parking pressure air path 12 and the spring-loaded brake cylinders 254c, 254d. The second electrically switchable vent valve 36 is also biased to a closed state, so that it interrupts the second vent path 30 in the event of a fault in the second control unit 28.

[0069] The first control unit 26 and the second control unit 28 can simultaneously open the first venting path 18 and the second venting path 30 in order to achieve a particularly high volume flow through the electropneumatic locking redundancy unit 10 and to quickly vent the locking compressed air path 12. However, only one of the venting paths 18, 30 can be opened at a time, for example, to vent at least one spring brake cylinder 254c, 254d.

[0070] In the first exemplary embodiment according to Fig. 2, the parking brake redundancy unit 10 further comprises a first pressure sensor 42, which is designed here to detect a pressure of the first venting path 18 and the second venting path 30. The first pressure sensor 42 is connected to the first control unit 26 and provides first pressure signals SP1 corresponding to the detected pressure to the first control unit 26. In other variants of the parking brake device 1, the first pressure sensor 42 can also be connected to the second control unit 28. Furthermore, two or more pressure sensors 42 can also be provided. In the first exemplary embodiment, the first pressure sensor 42 is arranged upstream of the first electrically switchable venting valve 34. Specifically, the first pressure sensor 42 is provided here to detect a pressure level prevailing at node 32.Thus, the first control unit 26 can determine, using the pressure signals provided by the first pressure sensor 42, whether the parking pressure pFS is present on the parking pressure air path 12 or whether the spring brake cylinders 254c, 254d are ventilated or vented.

[0071] Fig. 3 illustrates a second embodiment of the electropneumatic parking brake device 1, wherein the representation is essentially analogous to the first embodiment. Again, the first venting path 18 and the second venting path 30 are connected from the main connection 16 to the node 32 and divide downstream of the node 32 into two parallel venting paths 18, 30.

[0072] The first electrically switchable vent valve 34 in the second embodiment is designed analogously to the first embodiment. Thus, the first electrically switchable vent valve 34 in the second embodiment is also a 2 / 2-way solenoid valve that is preloaded into a closed state and controlled by the first control unit 26. The first outlet connection 34.2 also opens into the first redundant vent 14 in the embodiment according to Fig. 3. Here, however, in addition to the first electrically switchable vent valve 34, a fourth vent valve 40 is also provided in the first vent path 18. The fourth vent valve 40 can be controlled by the second control unit 28 and is part of the second redundant valve unit 24. The fourth electrically switchable vent valve 40 is arranged upstream of the first electrically switchable vent valve 34 in the first vent path 18.

[0073] In the second exemplary embodiment, the fourth electrically switchable vent valve 40 is also a 2 / 2-way valve and comprises a fourth inlet port 40.1 and a fourth outlet port 40.2. The second control unit 28 can supply a fourth magnet 40.3 of the fourth electrically switchable vent valve 40 with electrical energy in order to switch the fourth electrically switchable vent valve 40 between an open position, in which the fourth inlet port 40.1 and the fourth outlet port 40.2 are fluidically connected, and a closed position, in which the fourth electrically switchable vent valve 40 interrupts the first vent path 18. The electrically switchable vent valve 40 is also monostable. However, in contrast to the first electrically switchable vent valve 34, it is biased into the open position and not into the closed position.In the event of a fault in the second control unit 28, the fourth electrically switchable vent valve 40 therefore releases the first vent path 18.

[0074] Similarly, the second venting path 30 includes a third electrically switchable venting valve 38, which can be controlled by the first control unit 26. The third electrically switchable venting valve 38 is arranged upstream of the second electrically switchable venting valve 36 in the second venting path 30. Analogous to the fourth electrically switchable venting valve 40, the third electrically switchable venting valve 38 can also be switched to a closed position by energizing it, thus interrupting the second venting path 30.

[0075] In the second exemplary embodiment, which is shown in Fig. 3, the electropneumatic parking brake device 1 comprises, in addition to the first pressure sensor 42, a second pressure sensor 44. The second pressure sensor 44 provides second pressure signals SP2 for the second control unit 28. Here, the first pressure sensor 42 is designed to detect a first pressure p1 of the first venting path 18. Specifically, the first pressure sensor 42 detects the first pressure p1 between the fourth electrically switchable venting valve 40 and the first electrically switchable venting valve 34. Analogously, the second pressure sensor 44 is designed to detect a second pressure p2 of the second venting path 30 between the third electrically switchable venting valve 38 and the second electrically switchable venting valve 36.

[0076] Using the first pressure signals SP1, the first control unit 26 can, for example, determine whether the locking pressure pFS is present on the first locking compressed air path 12 and / or whether the fourth electrically switchable vent valve 40 is open or not.

[0077] In the second exemplary embodiment of the electropneumatic parking brake device 1, the parking compressed air path 12 can also be connected to a redundant vent 14, 15 via the first vent path 18 and / or the second vent path 30 and thus vented to the environment. For example, the first control unit 26 can supply the first electrically switchable vent valve 34 with electrical energy and thus switch it to the open position. If the second control unit 28 is fully functional, it does not supply the fourth magnet 40.3 of the fourth electrically switchable vent valve 40 with electrical energy and thus leaves the fourth electrically switchable vent valve 40 in the open position, in which it releases the first vent path 18.Even in the event of a total failure of the second control unit 28, the first control unit 26 can vent the parking compressed air path 12, since in this case the second control unit cannot supply the fourth electrically switchable vent valve 40 with electrical energy and thus cannot switch it to the closed switching position. The fourth electrically switchable holding valve 40, which is additionally provided compared to the first exemplary embodiment, further allows additional redundancy in the event that the first control unit 26 has a fault that causes the first control unit 26 to open the first electrically switchable vent valve 34 even though the parking brake of the vehicle 300 should not be engaged in a current (driving) situation. In the event of such a fault in the first control unit 26, the second control unit 28 can close the fourth electrically switchable vent valve 40 (the magnet 40).3) and thus interrupt the first venting path 18. An analogous functionality results for the third electrically switchable venting valve 38 arranged in the second venting path 30.

[0078] Preferably, the first electrically switchable vent valve 34, the second electrically switchable vent valve 36, the third electrically switchable vent valve 38 and the fourth electrically switchable vent valve 40 are arranged in a common housing (not shown in the figures).

[0079] Reference symbol (part of the description)

[0080] Parking brake device

[0081] Parking brake valve unit

[0082] Storage connection

[0083] Parking brake control unit, 8a, 8b Spring-loaded connections 0 Parking brake redundancy unit 2 Parking compressed air path 4 First redundancy venting 5 Second redundancy venting 6 Main connection 8 First venting path 2 First redundancy valve unit 4 Second redundancy valve unit 6 First control unit 8 Second control unit 0 Second venting path 2 Node 4 First electrically switchable venting valve 4.1 First inlet connection 4.2 First outlet connection 4.3 First magnet 6 Second electrically switchable venting valve 6.1 Second inlet connection 6.2 Second outlet connection 8 Third electrically switchable venting valve 0 Fourth electrically switchable venting valve 0.1 Fourth inlet connection 0.2 Fourth outlet connection 0.3 Fourth magnet 2 First pressure sensor 4 Second pressure sensor 00 Electronically controllable pneumatic brake system 02 Rear axle brake circuit Front axle brake circuit first Compressed air supply

[0084] Trailer brake circuit a-208f Service brake actuators a, 208b Front axle brake actuators c, 208d, Rear axle brake actuators e, 208f

[0085] Trailer module second compressed air supply

[0086] Primary system

[0087] Primary control unit

[0088] Vehicle-BUS

[0089] Autonomous driving unit first supply line first voltage source first operating axle modulator

[0090] Front axle modulator

[0091] Supply connection .1 first service brake pressure connection.2 second service brake pressure connection

[0092] Wheel speed sensor second operating axle modulator

[0093] Rear axle modulator

[0094] ABS valves

[0095] Central module

[0096] Secondary system

[0097] Secondary control unit second supply line second voltage source

[0098] Redundancy BUS

[0099] Redundant axis modulator

[0100] Redundancy brake pressure connection c-254f Spring brake cylinder first redundancy signal line second redundancy signal line 260 Select-High valve 262 Push-pull valve 264 Foot brake pedal 300 Vehicle 302 Commercial vehicle HA1 first rear axle HA2 second rear axle p1 first pressure P2 second pressure pB1 first service brake pressure pB2 second service brake pressure pB3 third service brake pressure pBR1 redundancy brake pressure pFS parking pressure

[0101] SA Brake request signals SB Service brake signals SD Wheel speed signals SFS Parking brake signal SP1 First pressure signals SP2 Second pressure signals

[0102] VA front axle

Claims

Patent claims 1. Electropneumatic parking brake device (1) for ventilating and venting one or more spring brake cylinders (254c, 254d, 254e, 254f) of an at least partially electronically controllable pneumatic brake system (200) for a vehicle (300), comprising an electropneumatic parking brake valve unit (2) with a supply connection (4) for receiving supply pressure (pV) from a compressed air supply (206, 210), and a parking brake control unit (6), wherein the parking brake valve unit (2) is designed to control a parking pressure (pFS) at at least one spring brake connection (8, 8a, 8b) as a function of a parking brake signal (SP), an electropneumatic parking brake redundancy unit (10) which is designed to vent at least one Spring brake cylinder (254c, 254d, 254e,254f) to connect a parking compressed air path (12) to a vent (14), wherein the parking brake redundancy unit (2) comprises at least one first main connection (16) for receiving a pressure (pFS) of the parking compressed air path (12), a first vent path (18) for directly venting the pressure (pFS, pV) into the environment and a second vent path (30) for directly venting the pressure (pFS, pV) into the environment, wherein a first electropneumatic redundancy valve unit (22) of the electropneumatic parking brake redundancy unit (10) is arranged in the first vent path (18) and can be controlled by a first control unit (26), wherein a second electropneumatic redundancy valve unit (24) of the electropneumatic parking brake redundancy unit (10) is arranged in the second vent path (30) and can be controlled by a second control unit (28), wherein the second control unit (28) is independent of the first control unit (26),and wherein the first venting path (18) and the second venting path (30) are mutually parallel venting paths (18, 30) for directly venting the received pressure (pFS, pV) of the locking compressed air path (12) into the environment., 2. Electropneumatic parking brake device () according to claim 1, wherein the first redundancy valve unit (22) has a first electrically switchable vent valve (34) which is arranged in the first vent path (18) and is designed to interrupt the first vent path (18) in a de-energized state, and wherein the second redundancy valve unit (24) has a second electrically switchable vent valve (36) which is arranged in the second vent path (30) and is designed to interrupt the second vent path (30) in a de-energized state.

3. Electropneumatic parking brake device (1) according to claim 2, wherein the first redundancy valve unit (22) has a third electrically switchable vent valve (38) arranged in the second vent path (30), and wherein the second redundancy valve unit (24) has a fourth electrically switchable vent valve (40) arranged in the first vent path (18).

4. Electropneumatic parking brake device (1) according to claim 3, wherein the third vent valve (38) is open in a de-energized state and wherein the fourth vent valve (40) is open in a de-energized state.

5. Electropneumatic parking brake device (1) according to one of claims 2 to 4, comprising a first pressure sensor (42) for detecting a first pressure (p1) of the first venting path (18), wherein the first pressure sensor (42) is designed to provide first pressure signals (SP1) corresponding to the detected first pressure (p1) for the first control unit (26); and comprising a second pressure sensor (44) for detecting a second pressure (p2) of the second venting path (30), wherein the second pressure sensor (44) is designed to provide second pressure signals (SP2) corresponding to the detected second pressure (p2) for the second control unit (28).

6. Electropneumatic parking brake device (1) according to claim 5, wherein the first pressure sensor (42) is arranged upstream of the first vent valve (34) and wherein the second pressure sensor (44) is arranged upstream of the second vent valve (36).

7. Electropneumatic parking brake device (1) according to one of claims 1 to 6, wherein the first electrically switchable vent valve (34) and the second electrically switchable vent valve (36) are 2 / 2-way valves.

8. An electronically controllable pneumatic braking system (200) for a vehicle (300), comprising at least a first front axle brake actuator (208a, 208b) and a second front axle brake actuator (208a, 208b) and at least a first rear axle brake actuator (208c, 208d, 208e, 208f) and a second rear axle brake actuator (208c, 208d, 208e, 208f); a primary system (212) with a primary control unit (214) at least for controlling the first front axle brake actuator (208a, 208b) and the second front axle brake actuator (208a, 208b) and / or for controlling the first rear axle brake actuator (208c, 208d, 208e, 208f) and the second rear axle brake actuator (208c, 208d, 208e, 208f); and an electropneumatic parking brake device (1) according to one of claims 1 to 7, wherein at least one first spring-loaded brake cylinder (254c, 254d, 254e, 254f) is connected to the at least one spring-loaded brake connection (8) of the electropneumatic parking brake valve unit (2).

9. Electronically controllable pneumatic brake system (200) according to claim 8, wherein at least the first spring brake cylinder (254c, 254d, 254e, 254f) is connected to the main connection (16) of the parking brake redundancy unit (1), wherein the parking brake redundancy unit (1) is switchable to connect the spring brake cylinder (254c, 254d, 254e, 254f) to the environment via the first venting path (18), via the second venting path (30) or via the first venting path (18) and the second venting path (30) in order to vent the spring brake cylinder (254c, 254d, 254e, 254f).

10. Electronically controllable pneumatic brake system (200) according to claim 8, wherein the main connection (16) is connected to a first compressed air supply (206, 210) of the brake system (200), and wherein the parking brake redundancy unit (10) is switchable to supply at least the first compressed air supply (206, 210) via the first venting path (18), via the second venting path (30) or via the first Venting path (18) and the second venting path (30) to the environment in order to vent the first compressed air supply (206, 210).

11. Electronically controllable pneumatic braking system (200) according to one of claims 8 to 10, wherein the primary control unit (214) is or comprises the first control unit (26).

12. Electronically controllable pneumatic brake system (200) according to one of claims 8 to 11, further comprising a secondary system (241) with a secondary control unit (242), wherein the secondary system (241) is designed to control the first front axle brake actuator (208a, 208b) and the second front axle brake actuator (208a, 208b) and / or to control the first rear axle brake actuator (208c, 208d, 208e, 208f) and the second rear axle brake actuator (208c, 208d, 208e, 208f) if an error is detected in the primary system (212).

13. Electronically controllable pneumatic braking system (200) according to claim 12, wherein the secondary control unit (242) is or comprises the second control unit (28).

14. Electronically controllable pneumatic brake system (200) according to one of claims 8 to 13, comprising a first voltage source (222) and a second voltage source (246), wherein the first voltage source (222) is provided for supplying the first control unit (26) with electrical voltage and wherein the second voltage source (246) is provided for supplying the second control unit (28) with electrical voltage.

15. Vehicle (300), in particular commercial vehicle (302), with at least one front axle (VA), at least one first rear axle (HA1) and an electronically controllable pneumatic braking system (1) according to one of the preceding claims 8 to 14.

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