Electropneumatic parking brake system with emergency braking function

Abstract

The invention relates to an electropneumatic parking brake device (1), comprising an electropneumatic parking brake valve unit (2), wherein the parking brake valve unit (2) is designed to control a parking pressure (pFS) at at least one working connection (8), and an electropneumatic parking brake redundancy unit (10), wherein a redundancy supply connection (16) of the parking brake redundancy unit (10) is connected to the working connection (8) of the electropneumatic parking brake valve unit (2), wherein the electropneumatic parking brake redundancy unit (10) has at least one operating position (20) and at least one venting position (22), wherein the electropneumatic parking brake redundancy unit (10) can be controlled by at least one first control unit (36) to switch from the venting position (22) to the operating position (20), and wherein the electropneumatic parking brake redundancy unit (10) is trained toto switch to the venting position (22) to provide an emergency braking function (50).

Description

The invention relates to an electropneumatic parking brake device for venting and venting one or more spring-loaded brake cylinders of an at least partially electronically controllable pneumatic brake system for a vehicle, comprising an electropneumatic parking brake valve unit having 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 designed to control a parking pressure at at least one working connection as a function of a parking brake signal. The invention further relates to an electronically controllable pneumatic brake system and a vehicle comprising such a brake system.Modern commercial vehicles frequently have an electronically controllable pneumatic brake system. As a rule, spring-loaded brakes are part of the brake system as parking brakes, which are also referred to as parking brakes. The parking brakes act by spring force and can be released or fixed by venting spring brake cylinders with a fixing pressure. The parking brake is generally used to secure a commercial vehicle in a standstill.For regulating a service brake pressure, valves are electronically controlled within a service brake system. The valves can be provided in so-called axle modulators or outside the same. The axle modulators can be automated or partially automated and / or can be electronically controlled by an autonomous unit. The parking brakes are also controlled electronically. For example, by actuating a solenoid valve, the venting or venting of the spring-loaded brake cylinders can be regulated. The spring-loaded brake cylinders can be combined with service brake cylinders, so that the spring-loaded brake and the service brake act on the same brake pistons. In order to avoid a mechanical overload of the brake pistons by adding brake forces from the service brakes and the spring-loaded brakes, suitable structural measures can be taken. If the service brakes are actuated while the parking brakes are active, the spring-loaded brake cylinders are simultaneously ventilated in order to avoid the addition of the braking forces. Such a function is also referred to as an "anti-compound function".In electropneumatic brake systems for modern vehicles, safety concepts are of high relevance. In particular in the case of vehicles having 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 in the event of a power failure of a control unit. Only in this way can the safety of the vehicle, its occupants and further road users be guaranteed. For this purpose, it is known to provide redundancy levels which can still provide an at least limited braking function even in the event of failure of a primary system. One possibility for increasing the reliability is to design the service brake system at least partially redundant. The parking brake can also be used in cases of emergency for decelerating the vehicle. For example, in the event of a failure of the service brake system, the spring brake cylinders of the vehicle can be vented in order to bring about braking of the vehicle.Partially redundant systems and methods providing redundancy belong to the prior art in various variants. From DE 10 2021 122 497 A1, for example, a method for operating an electropneumatic brake system for a vehicle is known, wherein the brake system comprises a service brake system and a parking brake system, wherein the parking brake system comprises at least one spring brake cylinder. The method is characterized by the steps of: providing a control signal for holding a spring accumulator venting pressure venting the at least one spring accumulator 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 ending the holding of the spring accumulator venting pressure for venting the at least one spring accumulator brake cylinder, thereby triggering a spring accumulator failure braking of the vehicle by the parking brake system, wherein the venting of the spring accumulator venting pressure takes place by a service brake venting function of the service brake system. The service brake venting function enables at least one venting path, which is opened in particular continuously or temporarily interrupted, in the service brake system for venting the at least one spring 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 a further outlet valve.Further partially redundant systems are known from DE 10 2022 101 142 A1, DE 10 2021 122 498 A1, DE 10 2021 122 499 A1, DE 10 2020 132 875 A1 and EP 3 145 769 B1.Even if known systems already partially provide a redundant possibility for engaging or releasing a parking brake, there is a need for possibilities for implementing an emergency braking function. In particular, in the aforementioned known possibilities, emergency braking of the vehicle in the event of failure of one or more technical systems may possibly not be possible, or may only be possible to a limited extent.It is therefore desirable to improve the provision of an emergency braking function. In particular, this should take place without or with only slight adverse effects during normal operation.At this point, the invention starts, the object of which is to specify an improved electropneumatic parking brake device which allows an emergency braking function to be provided.In a first aspect, the invention achieves this object with an electropneumatic parking brake device according to Claim 1. Proceeding from an electropneumatic parking brake device of the type mentioned at the beginning, an electropneumatic parking brake redundancy unit having a redundancy supply connection, a spring accumulator connection for at least indirect connection to a spring accumulator brake cylinder and at least one redundancy vent is furthermore provided. The redundancy supply connection of the parking brake redundancy unit is connected to the working connection of the electropneumatic parking brake valve unit for receiving the parking pressure. The electropneumatic parking brake redundancy unit has at least one operating position in which the redundancy supply connection is connected to the spring accumulator connection, and at least one venting position in which the spring accumulator connection is connected to the at least one redundancy venting. The electropneumatic parking brake redundancy unit can be actuated by at least one first control unit for switching from the venting position into the operating position, wherein the electropneumatic parking brake redundancy unit is designed to connect the spring accumulator connection to the redundancy venting independently of the electropneumatic parking brake valve unit for venting a spring accumulator brake cylinder connected to the spring accumulator connection in order to provide an emergency braking function.In known parking brake devices, the working connection of an electropneumatic parking brake valve unit is connected directly to a spring-loaded brake cylinder in order to vent the spring-loaded brake cylinder with the parking pressure that is controlled at the working connection. Known parking brake valve units are typically electrically switchable in order to either vent or vent the spring-loaded brake cylinder depending on the situation. One problem with known systems is that the parking brake valve unit may not provide this functionality in the event of a fault. The invention starts here by additionally providing the electropneumatic parking brake redundancy unit. The redundancy supply connection of the electropneumatic parking brake redundancy unit is connected to the working connection of the electropneumatic parking brake valve unit and can thus receive the parking pressure which is controlled at the working connection. The spring accumulator connection of the electropneumatic parking brake redundancy unit can be connected at least indirectly to a spring accumulator brake cylinder. A direct connection is made without the interposition of further functional units between the spring-loaded accumulator connection and the spring-loaded brake cylinder, whereas an indirect connection can also comprise further functional units, such as in particular valves. However, a direct connection can comprise lines, for example. In the electropneumatic parking brake device according to the invention, the electropneumatic parking brake redundancy unit is therefore also provided between the electropneumatic parking brake valve unit and the spring accumulator connection, which is provided for connection to at least one spring accumulator brake cylinder.The electropneumatic parking brake redundancy unit comprises at least one operating position and one venting position. In the operating position, the redundancy supply connection is connected to the spring storage connection. The parking pressure controlled by the electropneumatic parking brake valve unit and the parking pressure present at the redundancy supply connection can thus be controlled through to the spring accumulator connection when the electropneumatic parking brake redundancy unit is in the operating position. The electropneumatic parking brake redundancy unit is preferably designed to pass the parking pressure in the operating position essentially unchanged to the spring accumulator connection. This is preferably the case when the electropneumatic parking brake redundancy unit is designed to control a pressure at the spring accumulator connection which has a value which corresponds to 90% or more, preferably 95% or more, of the parking pressure. Preferably, a minimum flow cross section of the electropneumatic parking brake redundancy unit in the operating position between the redundancy supply connection and the spring accumulator connection is greater than or equal to a flow cross section of the working connection. In the venting position, the spring accumulator connection is connected to at least one redundancy venting of the electropneumatic parking brake redundancy unit. In the venting position, the electropneumatic parking brake redundancy unit can therefore vent a spring-loaded brake cylinder connected to the spring-loaded accumulator connection.The electropneumatic parking brake redundancy unit is designed to switch into the venting position for providing an emergency braking function independently of the electropneumatic parking brake valve unit for venting a spring accumulator brake cylinder connected to the spring accumulator connection, in order to vent a spring accumulator brake cylinder connected to the spring accumulator connection via the redundancy venting. The electropneumatic parking brake redundancy unit is preferably designed to switch passively into the venting position in order to provide the emergency braking function, that is to say without providing a corresponding emergency braking signal for the electropneumatic parking brake redundancy unit. Because the electropneumatic parking brake redundancy unit can provide the emergency braking function independently of the electropneumatic parking brake valve unit, venting of a spring-loaded brake cylinder connected to the spring-loaded accumulator connection is also possible if the parking brake control unit has a fault. The parking brake can then be used particularly reliably for providing emergency braking and safety is increased.In a first preferred development of the electropneumatic parking brake device, the electropneumatic parking brake redundancy unit is designed to provide the emergency brake function if the first control unit has a fault. This achieves an additional fault tolerance, since the emergency braking function can also be provided without a functional first control unit. The electropneumatic parking brake redundancy unit is preferably designed to assume the venting position in the de-energized state. In other words, the electropneumatic parking brake redundancy unit is preferably prestressed into the venting position.The electropneumatic parking brake redundancy unit preferably has at least one first electrically switchable redundancy valve, which, in a first redundancy valve operating position, opens up the redundancy supply connection to the first working path connecting the spring accumulator connection, with the result that the electropneumatic parking brake redundancy unit is in the operating position. Preferably, the first electrically switchable redundancy valve connects the spring accumulator connection to a redundancy vent in a first redundancy valve vent position, so that the electropneumatic parking brake redundancy unit is in the vent position. Preferably, the first electrically switchable redundancy valve can be controlled by the first control unit for switching from the first redundancy valve venting position into the first redundancy valve operating position. The switching of the electropneumatic parking brake redundancy unit into the working position can therefore be effected by switching the first electrically switchable redundancy valve into the first redundancy valve operating position. However, it can also be provided that at least one further valve must be switched in order to switch the electropneumatic parking brake redundancy unit into the operating position. The electropneumatic parking brake redundancy unit can therefore also be designed such that the switching of the first electrically switchable redundancy valve into the redundancy valve operating position is a partial prerequisite for a transfer of the electropneumatic parking brake redundancy unit into the operating position. In variants, it can also be provided that the electropneumatic parking brake redundancy unit can be brought into the operating position and / or into the venting position by switching at least one valve different from the first electrically switchable redundancy valve. For example, the electropneumatic parking brake redundancy unit may have a plurality of paths. The first electrically switchable valve can then be arranged, for example, in a first path, wherein a connection of redundancy supply connection and spring storage connection can then preferably also take place via an alternative second path.In a preferred development, the electropneumatic parking brake redundancy unit further comprises a second electrically switchable redundancy valve which, in a second redundancy valve operating position, opens up the redundancy supply connection to the spring accumulator connection, so that the electropneumatic parking brake redundancy unit is in the operating position. The second electrically switchable redundancy valve can preferably also comprise a second redundancy valve venting position in which it connects the spring accumulator connection to a redundancy venting, so that the electropneumatic parking brake redundancy unit is in the venting position. The second electrically switchable redundancy valve can be designed substantially analogously to the first electrically switchable redundancy valve. In particular, it can also be provided that the switching of the second electrically switchable redundancy valve into the redundancy valve operating position is only a sub-condition for the switching of the electropneumatic parking brake redundancy unit into the operating position and / or that the switching of the second electrically switchable redundancy valve into the redundancy venting position is only a sub-condition for the switching of the electropneumatic parking brake redundancy unit into the venting position. For example, the first electrically switchable redundancy valve and the second electrically switchable redundancy valve can be connected in series, wherein the electropneumatic parking brake redundancy unit is in the operating position if the first electrically switchable redundancy valve is in the first redundancy valve operating position and the second electrically switchable redundancy valve is in the second redundancy valve operating position. The first working path and the second working path can therefore also be segments of a common working path.Preferably, however, the first electrically switchable redundancy valve and the second electrically switchable redundancy valve are arranged in parallel paths of the electropneumatic parking brake redundancy unit. Particularly preferably, the first working path and the second working path of the electropneumatic parking brake redundancy unit are parallel working paths. The first working path and the second working path are then preferably parallel working paths, which respectively form at least partial sections of a compressed air path between redundancy supply connection and spring storage connection. It should be understood that the first working path and the second working path may be connected to the same redundancy supply connection. In alternative embodiments, each working path can also be connected to its own or multiple redundancy supply connections. Furthermore, the working path and the second working path can be connected to the same spring accumulator connection or to different spring accumulator connections.In a development of the variant with a parallel first working path and second working path, the first working path and the second working path are connected to one another via a selection valve, preferably adjacent to the spring accumulator connection. Working paths connected adjacent to the spring accumulator connection are connected to one another in particular at subsection which are connected directly to the spring accumulator connection, in particular are not separated from the spring accumulator connection by switchable valves. The selection valve is preferably designed to connect that working path which leads to a higher pressure from the first working path and the second working path to the spring accumulator connection. The selection valve is therefore preferably designed as a so-called "select-high valve".Preferably, the electropneumatic parking brake redundancy unit can be actuated by a second control unit for switching from the venting position into the operating position. The electropneumatic parking brake redundancy unit can then be actuated by the first control unit and by the second control unit for switching from the venting position into the operating position. The electropneumatic parking brake redundancy unit can preferably be switched from the venting position into the operating position when said parking brake redundancy unit is actuated simultaneously by the first control unit and by the second control unit. In other embodiments, in particular in embodiments with a parallel first working path and second working path, however, it can also be provided that the electropneumatic parking brake redundancy unit can be switched from the venting position into the operating position by the first control unit alone and / or by the second control unit alone.Preferably, the second electrically switchable redundancy valve can be controlled by the second control unit for switching from the second redundancy valve venting position into the second redundancy valve operating position. Preferably, the first electrically switchable redundancy valve can be controllable by the first control unit for switching from the first redundancy valve venting position into the first redundancy valve operating position. Thus, for example and preferably, the first control unit can be provided for actuating the first working path and the second control unit can be provided for actuating the second working path.In a preferred embodiment, the electropneumatic parking brake redundancy unit is designed to provide the emergency braking function if the first control unit has a fault or if the second control unit has a fault. Alternatively or additionally, the electropneumatic parking brake redundancy unit can be designed to provide the emergency braking function if the first control unit and the second control unit have a fault. In the event of a fault in the first control unit and / or the second control unit, the electropneumatic parking brake redundancy unit can provide the emergency braking function or switch it into the venting position and thus connect the spring accumulator connection to at least one redundancy venting.The electropneumatic parking brake valve unit and the electropneumatic parking brake redundancy unit are preferably connected in series along a parking pressure air path. The parking pressure air path is preferably provided for venting and venting at least one spring brake cylinder.The series connection of electropneumatic parking brake valve unit and electropneumatic parking brake redundancy unit permits high operational reliability. The electropneumatic parking brake redundancy unit can thus prevent a spring brake cylinder from being ventilated by a faulty electropneumatic parking brake valve unit. The electropneumatic parking brake redundancy unit is preferably arranged downstream of the electropneumatic parking brake valve unit, that is to say closer to the spring-loaded brake cylinder.In a preferred development, the electropneumatic parking brake device comprises a protective device having a first parking pressure connection, an operating pressure connection and an operating connection, wherein the parking pressure connection is connected to the spring accumulator connection of the electropneumatic parking brake redundancy unit for receiving the parking pressure, wherein the operating pressure connection can be connected to a service brake circuit for receiving a service brake pressure, and wherein the protective device is designed to control the higher pressure from the parking pressure and the service brake pressure at the operating connection. The protective device can prevent both an operating pressure and a locking pressure from being conducted to a brake actuator connected to the electropneumatic parking brake device.In a second aspect, the invention achieves the object mentioned at the beginning with an electronically controllable pneumatic brake system for a vehicle, in particular a commercial vehicle. The electronically controllable pneumatic brake system comprises at least one parking brake actuator with a spring-loaded brake cylinder, a first compressed air supply for providing supply pressure, and an electropneumatic parking brake device according to one of the above-described preferred embodiments according to the first aspect of the invention. The supply connection of the electropneumatic parking brake valve unit is connected to the first compressed air supply and the spring accumulator connection of the electropneumatic parking brake redundancy unit is connected to the spring accumulator brake cylinder. For ventilating the spring-loaded brake cylinder, compressed air provided by the compressed air supply can thus be provided to the spring-loaded brake cylinder via the electropneumatic parking brake device. The electropneumatic parking brake device can pass the supply pressure through it unchanged or modulate it in pressure level and / or volume flow.In a first preferred development, the electronically controllable pneumatic brake system comprises an electropneumatic parking brake device which can be actuated by a second control unit for switching from the venting position into the operating position, wherein the electropneumatic parking brake redundancy unit is designed to provide the emergency brake function only if the first control unit and the second control unit have a fault. According to the preferred development, the spring brake cylinder connected to the spring brake connection is therefore only connected to at least one redundancy vent by the electropneumatic parking brake redundancy unit if both the first control unit and the second control unit have a fault. A fault of a control unit may be present, for example, if it is not supplied with electrical energy, if it has a software fault and / or if it has a hardware fault, for example a cable break.The electronically controllable brake system preferably further comprises 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. Particularly preferably, the second voltage source is provided for supplying the second control unit with electrical voltage. The first voltage source and the second voltage source are preferably voltage sources independent of one another. The provision of mutually independent voltage sources can further increase the reliability of the brake system, since a failure of an individual voltage source does not cause a total failure of the parking brake system.In a preferred variant of the electronically controllable brake system, the first control unit can switch the electropneumatic parking brake redundancy unit from the venting position into the operating position only when the first voltage source and the second voltage source provide electrical energy. It should be understood that the first control unit does not have to be supplied with electrical energy for this purpose both by the first voltage source and by the second voltage source. Thus, the first control unit can also be supplied, for example, only by the first voltage source. However, it can also be advantageous in such embodiments that the first control unit can only switch the electropneumatic parking brake redundancy unit from the venting position into the operating position when both voltage sources provide electrical energy. Thus, the first control unit can optionally also be ready for use during system safety even in the event of a failure of the second voltage source and therefore venting of the spring-loaded brake is undesirable.Preferably, the electronically controllable pneumatic brake system further comprises an autonomous driving unit, wherein the autonomous driving unit is the first control unit. A unit for autonomous driving can be, in particular, a so-called virtual driver, which generates driving commands on the basis of sensor data, operating data, route data, target data and the like data and provides these to the vehicle. Driving commands may include steering commands, acceleration commands and braking commands, in particular a braking request AB.In alternative embodiments, the electronically controllable pneumatic brake system comprises at least one service brake actuator and a service brake system having a service brake control unit at least for actuating the at least one service brake actuator, wherein the service brake control unit is the first control unit. The service brake control unit is typically independent of the parking brake control unit.In addition to the service brake system, the electronically controllable pneumatic brake system preferably further comprises a secondary system having a secondary control unit, wherein the secondary system is designed to actuate the at least one service brake actuator if a fault is determined in the service brake system. The secondary system can also be referred to as a service brake redundancy system.In variants in which the electronically controllable pneumatic brake system comprises a secondary system and in which the electropneumatic parking brake redundancy unit of the electropneumatic parking brake device of the electronically controllable pneumatic brake system can be actuated by a second control unit for switching from the venting position into the operating position, the secondary control unit can be or comprise the second control unit. In this variant, an already present control unit can then be used to actuate the electropneumatic parking brake redundancy unit.In variants in which a unit for autonomous driving of the electronically controllable pneumatic brake system is or comprises the first control unit, the electronically controllable pneumatic brake system can have at least one service brake actuator and a service brake system with a service brake control unit at least for actuating the at least one service brake actuator. The service brake control unit is then preferably the second control unit. Thus, two units already present in the brake system can be used to actuate the electropneumatic locking redundancy unit for switching from the venting position into the operating position. The electropneumatic detection redundancy unit is preferably designed to switch automatically into the venting position if the autonomous driving unit (the first control unit) or the service brake control unit (the second control unit) have a fault. In alternative preferred embodiments, the electropneumatic parking redundancy unit is designed to switch automatically into the venting position if the autonomous driving unit (the first control unit) and the service brake control unit (the second control unit) have a fault.According to a third aspect of the invention, the object mentioned at the beginning is achieved by a utility vehicle having at least one front axle, at least one first rear axle and an electronically controllable pneumatic brake system according to one of the above-described preferred embodiments of an electronically controllable pneumatic brake system according to the second aspect of the invention. In a fourth aspect, the invention achieves the object mentioned at the beginning by a method for operating an electronically controllable pneumatic brake system for a vehicle, which comprises a first control unit and a parking brake system having at least one spring-loaded brake cylinder and an electropneumatic parking brake device. In particular, the method is a method for operating an electronically controllable pneumatic brake system according to one of the above-described preferred embodiments of an electronically controllable pneumatic brake system according to the second aspect of the invention. The method according to the fourth aspect of the invention comprises the following steps: providing at least one redundancy switching signal at an electropneumatic parking brake redundancy unit of the electropneumatic parking brake device; switching the parking brake redundancy unit into an operating position in response to the provision of the at least one redundancy switching signal; providing a parking brake signal at a parking brake control unit of an electropneumatic parking brake valve unit of the electropneumatic parking brake device; controlling a parking pressure by the electropneumatic parking brake valve unit at a working connection of the electropneumatic parking brake valve unit in dependence on the parking brake signal provided at the parking brake control unit; passing the parking pressure, which is controlled at the working connection, from a redundancy supply connection of the parking brake redundancy unit to a spring accumulator connection of the parking brake redundancy unit, venting a spring accumulator brake cylinder connected to the spring accumulator connection of the parking brake redundancy unit; and automatically and independently of the electropneumatic parking brake valve unit, switching the parking brake redundancy unit from the operating position into a venting position, in which the spring accumulator connection is connected to a redundancy venting of the parking brake redundancy unit, in order to vent the spring accumulator brake cylinder in order to provide an emergency braking function. By switching the parking brake redundancy unit from the operating position into the venting position, the spring accumulator connection is connected to the redundancy venting and the spring accumulator brake cylinder connected to the spring accumulator connection is vented. This clamps the parking brake on and the vehicle is braked. The switching of the parking brake redundancy unit for providing the emergency braking function is preferably carried out if supply of the parking brake redundancy unit with electrical energy and / or redundancy switching signals is interrupted and / or if the provision of the at least one redundancy switching signal is omitted. Preferably, the parking brake valve unit switches automatically from the operating position into the venting position in order to provide the emergency braking function if a first control unit for actuating the electropneumatic parking brake redundancy unit and / or a second control unit for actuating the electropneumatic parking brake redundancy unit has a fault. Alternatively or additionally, the automatic switching can also take place if a first voltage source and / or a second voltage source of the brake system fails.When passing through the fixing pressure, the fixing pressure can also be varied in pressure level and / or volume flow. The passage is particularly preferably effected, however, without substantial influence on the fixing pressure, which goes beyond customary pressure losses in line components.It is to be understood that the electronically controllable pneumatic brake system according to the second aspect of the invention, the commercial vehicle according to the third aspect of the invention and the method for operating an electronically controllable pneumatic brake system according to the fourth aspect of the invention have the same and similar sub-aspects as are laid down in particular in the dependent claims relating to the first aspect of the invention and to the second aspect of the invention.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, but rather the drawings are embodied in schematic and / or slightly distorted form, if this is useful for explanation. With regard to additions to the teachings that can be directly recognized from the drawings, reference is made to the relevant prior art. It should be understood that various modifications and changes may be made to the form and detail of an embodiment without departing from the general spirit of the invention. The features of the invention disclosed in the description, in the drawings and in the claims can be essential for the development of the invention both individually and in any combination. Moreover, 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 limited compared to the object claimed in the claims. In the case of specified rated ranges, values lying within the stated limits should also be disclosed as limit values and can 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 function.Further advantages, features and details of the invention are apparent from the following description of the preferred embodiments and from the drawings, in which: FIG. 1 shows a schematic illustration of a utility vehicle having an electronically controllable pneumatic brake system; FIG. 2 shows a first exemplary embodiment of an electropneumatic parking brake device, FIG. 3 shows a second exemplary embodiment of an electropneumatic parking brake device; and FIG. 4 shows a block diagram illustrating a method for operating an electronically controllable pneumatic brake system.FIG. 1 shows an electronically controllable pneumatic brake system 200 having an electropneumatic parking brake device 1. the electronically controllable pneumatic brake system 200 is used in the present case in a vehicle 300 designed as a commercial vehicle 302, which is shown here in a highly schematic manner, in particular having a front axle VA, a first rear axle HA 1 and a second rear axle HA 2.The electronically controllable pneumatic brake system 200 comprises first, second, third, fourth, fifth and sixth service brake actuators 208 a- 208 ffor each wheel of the vehicle 300. To provide brake pressures to the first through sixth service brake actuators 208 a- 208 f, a rear axle brake circuit 202 and a front axle brake circuit 204 are provided. The service brake actuators 208 a, 208 bare associated with the front axle VA and are therefore also referred to as front axle brake actuators 208 a, 208 b. Analogously, the service brake actuators 208 c- 208 fassociated with the rear axles HA 1, HA 2 are also referred to as rear axle brake actuators 208 c- 208 f. 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 utility vehicle 300 is designed here as a towing vehicle and comprises a trailer brake circuit 207 having a trailer module 209, which is provided for supplying a trailer (not illustrated) connected to the utility vehicle 300 with compressed air.The electronically controllable pneumatic brake system 200 has an operating level and a first redundancy level. In the operating level, the electronically controllable pneumatic brake system 200 comprises a service brake system 212 with an electronic service brake control unit 214 which controls the electronically controllable pneumatic brake system 200 in the operating level. The service brake electronic control unit 214 is connected via a vehicle bus 216 to an autonomous driving unit 218 and receives brake request signals SA therefrom. Moreover, the service brake electronic control unit 214 is connected via a first supply line 220 to a first voltage source 222 and is supplied with electrical energy therefrom. The service brake electronic control unit 214 converts the brake request signals SA and, based thereon, outputs service brake signals SB to a first service axle modulator 224. The first operating axle modulator 224 is here 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 at the service brake control unit 214.The first operating axle modulator 224 is connected to the second compressed air supply 210 and receives supply pressure pV therefrom. The first operating axle modulator 224 controls, based on the received operating brake signals SB, a first service brake pressure pB 1 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 accordance with the wheel, and the first operating axle modulator 224 is designed as a dual-channel modulator. In other embodiments, however, the first service brake pressure connection 232.1 and the second service brake pressure connection 232.2 can also be combined and the first operating axle modulator 224 can be designed as a single-channel axle modulator which controls the first service brake pressure pB1 in the proper axis.A first wheel speed sensor 234 is also provided on the front axle VA, which first wheel speed signals SD are provided to the service brake control unit 214. The service brake 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, so as to achieve slip control or ABS modulation of the first service brake pressure pB 1 and to avoid locking front wheels of the vehicle 300.Furthermore, the electronically controllable pneumatic brake system 200 comprises, in the operating plane, a second operating axle modulator 236, which is provided for the first and the second rear axle HA 1, HA 2 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 service brake control unit 214 to form a module which is referred to here as a central module 240. However, it should be understood that the rear axle modulator 237 and the service brake control unit 214 may also be separate or structurally separate. The service brake 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 service brake electronic control unit 214 controls the rear axle modulator 237 in accordance with the brake request signals SA that the service brake control unit 214 has received from the autonomous driving unit 218.An operating supply port 230 of the second operating axle modulator 236 is connected to the first compressed air supply 206 and receives supply pressure pV therefrom. In accordance with its activation by the service brake control unit 214, the rear axle modulator 237 controls at least one second service brake pressure pB 2, but in the exemplary embodiment shown here it also controls a third service brake pressure pB 3. The second service brake pressure pB2 is provided for the right vehicle side and the third service brake pressure pB3 is provided for the left vehicle side in the exemplary embodiment shown in FIG. 1. The rear-axle modulator 237 is therefore designed here as a dual-channel axle modulator. The second service brake pressure pB2 is determined for a fourth and a 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, however, the first operating axis modulator 236 can also be designed as a single-channel modulator or as a multi-channel modulator having more than two outputs.In the redundancy level, the electronically controllable pneumatic brake system 200 comprises a secondary control unit 242 of a secondary system 241, which is provided to control the electronically controllable pneumatic brake system 200 in the event that the operating level has one or more errors. The secondary control unit 242 can thus control the electronically controllable pneumatic brake system 200, for example in the event of a power failure in the first voltage source 222, an electronic fault in the service brake control unit 214 or the like.The secondary electronic control unit 242 is also connected to the autonomous driving unit 218 via the vehicle bus 216 and also receives brake request signals SA therefrom. In contrast to the service brake 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 therefrom. The first and second voltage sources 222, 246 are independent of each other such that a failure in the first voltage source 222 does not result in a loss of the second voltage source 246, and vice versa. The service brake electronic control unit 214 and the secondary electronic control unit 242 are thus electrically independent of one another.In order to be able to exchange signals, the service brake 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 service brake control unit 214 and only take over the control of the electronically controllable pneumatic brake system 200 if the service brake control unit 214 is not available or is no longer correctly available. However, in variants, service brake control unit 214 and secondary control unit 242 can also communicate via vehicle BUS 216.In the redundancy level, a redundancy axle modulator 250 is provided, which is connected to the secondary control unit 242 and receives redundancy brake signals SR from the latter. In the exemplary embodiment according to FIG. 1, the secondary control unit 242 is integrated into the redundancy axis modulator 250. In other variants, however, the secondary control unit 242 and the redundancy axle modulator 250 can also be physically separate units from one another.The redundancy 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 also provide supply pressure pV if the first compressed air supply 206 has failed. In other embodiments, however, the redundancy 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.The redundancy axle modulator 250 controls a redundancy brake pressure pBR 1 at a redundancy brake pressure connection 252 as a function of the redundancy brake signals SR. The redundancy brake pressure pBR1gesteuerte at the redundancy brake pressure port 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 realize, for example, lateral modulation of redundancy brake pressures.The secondary control unit 242 can actuate the redundancy axle modulator 250 in such a way that, in the event of a fault in the service brake control unit 214, a brake pressure, namely the redundancy brake pressure pBR 1, is nevertheless provided at the front axle brake actuators 208 a, 208 b. Unlike the illustration in FIG. 1, the redundancy level can also be provided for braking the first and second rear axles HA 1, HA 2. This can be realized by means of the redundancy axis modulator 250 or by means of a second redundancy axis modulator. The secondary control unit 242 can then preferably also be provided for controlling such a second redundancy axis modulator.The brake actuators assigned to the wheels of the rear axles HA 1, HA 2 are designed as double-acting brake actuators in the embodiment of the electronically controllable pneumatic brake system 200 shown in FIG. 1, which are also referred to as tri-stop cylinders. In addition to the service brake actuators 208 c- 208 f, these also each comprise a spring-loaded brake cylinder 254 c- 254 f. The spring-loaded brake cylinders 254 c- 254 fare designed to tension the brakes of the vehicle 300 when they are depressurized or depressurized. The spring-loaded brake cylinders 254 c- 254 fare thus advantageously usable as a parking brake, which does not have to be provided with compressed air for braking the rear axles HA 1, HA 2. To release the rear wheels, the spring-loaded brake cylinders 254 c- 254 fmust be ventilated with a parking pressure pFS. This parking pressure pFS entgegen the spring accumulator and releases the brakes of the vehicle 300. The spring-loaded brake cylinders 254 c- 254 fare part of a parking brake system 203.To provide the parking brake function, the electronically controllable pneumatic brake system 200 comprises the electropneumatic parking brake device 1. In the exemplary embodiment shown, the supply connection 4 is connected to the first compressed air supply 206. However, the parking brake valve unit 2 could also be supplied with supply pressure pV from the second compressed air supply 210.The electropneumatic parking brake valve unit 2 includes a parking brake control unit 6 connected to the autonomous driving unit 218 via the vehicle bus 216. For engaging 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 parking brake signal thereupon provides the parking pressure pSW at a working connection 8.The working connection 8 of the electropneumatic parking brake valve unit 2 is connected in FIG. 1 to a redundancy supply connection 16 of an electropneumatic parking brake redundancy unit 10 of the electropneumatic parking brake device 1. The electropneumatic parking brake valve unit 2 controls the parking pressure pSW at its working connection 8 in response to the parking brake signals SFS and thus provides the same at the redundancy supply connection 16. The electropneumatic parking brake redundancy unit 10 further comprises a spring accumulator connection 18, which in FIG. 1 is connected directly to the spring accumulator brake cylinders 208 c, 208 d, 208 e, 208 fof the electronically controllable pneumatic brake system 200.In the embodiment shown, the electropneumatic parking brake valve unit 2 and the electropneumatic parking brake redundancy unit 10 are thus connected in series along a parking pressure air path 12 which is provided here for supplying the spring-loaded brake cylinders 208 c, 208 d, 208 e, 208 fwith parking pressure pFS. In particular, in the embodiment shown in FIG. 1, the electropneumatic parking brake valve unit 2 is connected to the spring-loaded brake cylinders 208 c, 208 d, 208 e, 208 fvia only the electropneumatic parking brake redundancy unit 10. The electropneumatic parking brake valve unit 2 can therefore not supply the spring-loaded brake cylinders 208 c, 208 d, 208 e, 208 fwith a parking pressure pFSby the electropneumatic parking brake redundancy unit 10.The electropneumatic parking brake redundancy unit 10 can be switched here between an operating position 20 and a venting position 22.In the operating position 20, the electropneumatic parking brake redundancy unit 10 connects the redundancy supply connection 16 to the spring accumulator connection 18. Here, the electropneumatic parking brake redundancy unit 10 controls the parking pressure pFSprovided at the redundancy supply connection 16 in a substantially unchanged manner to the spring accumulator connection 18 when it is in the operating position 20. In this case, the parking pressure pFSis therefore also applied to the spring accumulator connection 18 and can thus be provided at the spring accumulator brake cylinders 208 c, 208 d, 208 e, 208 f.In the venting position 22, on the other hand, the spring accumulator connection 18 is connected to a redundancy vent 24 of the electropneumatic parking brake redundancy unit 10. In the venting position 22, the electropneumatic parking brake redundancy unit 10 vents the spring-loaded brake cylinders 208 c, 208 d, 208 e, 208 fconnected to the spring-loaded connection 18 directly into the environment. If the electropneumatic parking brake redundancy unit 10 is in the venting position 22, the parking brake of the vehicle 300 is therefore engaged or the wheels of the rear axles HA 1 and HA 2 of the vehicle 300 are braked.In FIG. 1, a first electrically switchable redundancy valve 26 and a second electrically switchable redundancy valve 28 of the electropneumatic parking brake redundancy unit 10 are also indicated. The structure of the electropneumatic parking brake redundancy unit 10 will be explained further later with reference to FIGS. 2 and 3.The electropneumatic parking brake redundancy unit 10 can be actuated by at least one control unit of the electronically controllable pneumatic brake system 200 for switching from the venting position 22 into the operating position 20. For this purpose, the electropneumatic parking brake redundancy unit 10 in FIG. 1 is connected by way of example via a first redundancy signal line 256 to the secondary control unit 242. This provides a first redundancy switching signal SR 1 to the electropneumatic parking brake redundancy unit 10 via the redundancy signal line 256.In FIG. 1, the spring-loaded brake cylinders 254 c- 254 fare directly connected to the spring-loaded connection 18. In a preferred variant, however, the electropneumatic parking brake device 1 can additionally comprise a protective device 30 (FIG. 3 ), which is arranged between the spring accumulator connection 18 and the spring accumulator brake cylinders 254 c- 254 fand between the working connection 8 and the redundancy supply connection 16.Preferably, the electropneumatic locking redundancy unit 10 is switched from the venting position 22 into the operating position 20 when the vehicle 300 is put into operation, in particular when an ignition of the vehicle 300 is actuated. The electropneumatic parking brake valve unit 2 can then ventilate the spring-loaded brake cylinders 254 c, 254 d, 254 e, 254 fvia the electropneumatic parking redundancy unit 10 and thus release the parking brake of the vehicle 300. The vehicle 300 is then ready to drive. Preferably, the electropneumatic locking redundancy unit 10 is permanently held in the operating position 20 during normal operation. Any venting of the spring-loaded brake cylinders that may be necessary can then also take place 254 c, 254 d, 254 e, 254 fvia the electropneumatic parking brake valve unit 2. The electropneumatic detection redundancy unit 10 preferably switches into the venting position 22 for providing an emergency braking function only when a fault is present, in particular in the event of a total electrical failure of the electronically controllable pneumatic brake system 200 or in the event of a failure of a plurality of control units 6, 214, 218, 242 of the electronically controllable pneumatic brake system 200.Although only the secondary control unit 242 for controlling the electropneumatic parking redundancy unit 10 is shown in the exemplary embodiment shown in FIG. 1, it should be understood that the electropneumatic parking redundancy unit 10 can also be controlled individually or in combination by further control units of the electronically controllable pneumatic brake system 200 in order to switch from the venting position 22 into the operating position 20. In particular, the electropneumatic parking redundancy unit 10 can also be actuatable by the autonomous driving unit 218 and / or the service brake control unit 214.FIG. 2 now schematically shows a first exemplary embodiment of the electropneumatic parking brake device 1. Furthermore, FIG. 2 shows, by way of example, only one spring-loaded brake cylinder 254. In the first exemplary embodiment, the electropneumatic parking redundancy unit 10 comprises only a first electrically switchable redundancy valve 32. the working connection 8 of the electropneumatic parking brake valve unit 2 is connected here to a first redundancy valve supply connection 32.1 of the redundancy valve 32, which forms the redundancy supply connection 16 here. The first redundancy valve 32 is an electrically switchable 3 / 2-way valve. In addition to the first redundancy valve supply connection 32.1, the first redundancy valve 32 comprises a first redundancy valve working connection 32.2, which in the first exemplary embodiment of the electropneumatic parking brake device 1 forms the spring storage connection 18 of the electropneumatic parking redundancy unit 10, and a first redundancy valve venting connection 32.3, which here forms the redundancy venting 24.The first electrically switchable redundancy valve 32 has two switching positions. A first redundancy valve venting position 32.4 shown in FIG. 2 is also the venting position 22 of the electropneumatic fixed redundancy unit 10 here. The first electrically switchable redundancy valve 32 is prestressed into this redundancy valve venting position 32.4 or the venting position 22 and automatically returns into this redundancy valve venting position 32.4 provided that a first electromagnet 32.6 of the first electrically switchable redundancy valve 32 is not supplied with electrical energy or is energized. In the redundancy valve venting position 32.4, the first redundancy valve working connection 32.2 is conductively connected to the first redundancy valve venting connection 32.3, and a first working path 34 of the electropneumatic fixed redundancy unit 10 is blocked or interrupted. The spring accumulator connection 18 is then connected to the redundancy vent 24 via the first electrically switchable redundancy valve 32, so that the spring accumulator brake cylinder 254 is vented via the electropneumatic locking redundancy unit 10.In a first redundant valve operating position 32.5, which here is also the operating position 20 of the electropneumatic fixed redundancy unit 10, the first redundant valve supply connection 32.1 and the first redundant valve working connection 32.2 are connected in a fluid-conducting manner. In the first redundancy valve operating position 32.5, the first electrically switchable redundancy valve 32 opens up the first working path 34. The parking pressure pFS, which is controlled by the electropneumatic parking brake valve unit 2, thus reaches the parking brake cylinder 254 via the redundancy supply connection 16 and the spring accumulator connection 18.The electropneumatic locking redundancy unit 10 can be controlled by a first control unit 36 for switching between the venting position 22 and the operating position 20. As explained with reference to FIG. 1, the first control unit 36 may be the secondary control unit 242. In other variants, however, the first control unit 36 can preferably also be formed by the autonomous driving unit 218 or the service brake control unit 214. The first control unit 36 provides the first redundancy control signals SR 1 at the first electrically switchable redundancy valve 32. Here, the first redundancy control signal SR 1 takes the form of electrical energy which is provided at the first magnet 32.6, which thereupon switches the first electrically switchable redundancy valve 32 into the redundancy valve operating position 32.5 and holds it there. For supplying current, the first electrically switchable redundancy valve 32 comprises first redundancy valve signal connections 32.7. One or more of the redundancy valve signal connections 32.7 are connected to the first control unit 36.However, it can also be provided that, in addition to the first control unit 36, a second control unit 38 for switching the electropneumatic detection redundancy unit 10 is also connected to the first electrically switchable redundancy valve 32. In such variants, the first electrically switchable redundancy valve 32 can then be jointly switchable by only one control unit from the first control unit 36 and the second control unit 38 or only by the first control unit 36 and the second control unit 38.The first control unit 36 may be the autonomous driving unit 218, the service brake control unit 214, the secondary control unit 242, or the parking brake control unit 6. The second control unit 38 may be the autonomous driving unit 218, the service brake control unit 214, the secondary control unit 242, or the parking brake control unit 6, wherein the second control unit 38 is preferably a control unit 36 different from the first control unit 36.In the first exemplary embodiment according to FIG. 2, the electropneumatic parking brake device 1 furthermore comprises the protective device 30, which comprises a first protective connection 30.1, which is connected to the spring-loaded storage connection 18. A second protective connection 30.2 of the protective device 30 is provided for receiving a service brake pressure pB1, pB2, pB3. The first protective connection 30.1 is also referred to as a locking pressure connection 30.1. The second protective connection 30.2 is also referred to as the operating pressure connection 30.2. A third protective connection 30.3 of the protective device 30, which is also referred to as the protective device working connection 30.3, is connected to the spring-loaded brake cylinder 254. The protective device comprises a first shuttle valve 40, which delivers the higher of the pressures present at the first protective connection 30.1 and at the second protective connection 30.2 to a second shuttle valve 42. The first shuttle valve 40 is thus a so-called select-high valve. This makes it possible to ensure that a parking pressure pFSand a service brake pressure pB 1, pB 2, pB 3 are not simultaneously applied to the spring brake cylinder.FIG. 3 shows a second exemplary embodiment of the electropneumatic parking brake device 1. the electropneumatic parking redundancy unit 10 according to the second exemplary embodiment comprises a second working path 44 which runs parallel to the first working path 34 from the redundancy supply connection 16 to the spring storage connection 18. In this case, the redundancy supply connection 16 and the spring storage connection 18 are therefore not formed by connections 32.1, 32.2 of the first electrically switchable redundancy valve 32. The first redundancy valve venting connection 32.3 is connected here to a first redundancy venting 24.1.In the second working path 44, a second electrically switchable redundancy valve 46 is arranged here. This is substantially identical to the first electrically switchable redundancy valve 32. The second electrically switchable redundancy valve 46 comprises a second redundancy valve supply connection 46.1, a second redundancy valve working connection 46.2 and a second redundancy valve venting connection 46.3. The second redundancy valve venting connection 46.3 is connected to a second redundancy venting 24.2. However, the first redundancy valve venting connection 32.3 and the second redundancy valve venting connection 46.3 could also be connected to a common redundancy venting 24. The second electrically switchable redundancy valve 46 is biased into a second redundancy valve venting position 46.4. By supplying a second magnet 46.6 of the second electrically switchable redundancy valve 46, the second electrically switchable redundancy valve 46 can be switched into a second redundancy valve operating position 46.5. A second control unit 38 is preferably provided for controlling the second electrically switchable redundancy valve 46. Particularly preferably, the first control unit 36 is designed to actuate the first electrically switchable redundancy valve 32 and the second control unit 38 is provided to actuate the second electrically switchable redundancy valve 46.In the second exemplary embodiment, the electropneumatic fixed redundancy unit 10 is either controlled by switching the first electrically switchable redundancy valve 32 from the first redundancy valve venting position 32.4 into the first redundancy valve operating position 32.5 and / or by switching the second electrically switchable redundancy valve 46 from the second redundancy valve venting position 46.4 into the second redundancy valve operating position 46.5 from the venting position 22 into the operating position 20, in which the fixed pressure pFSprovided at the redundancy supply connection 16 is controlled through to the spring accumulator connection 18.In the second exemplary embodiment of the electropneumatic parking brake device 1, the electropneumatic parking redundancy unit 10 comprises a selection valve 48 adjacent to the spring accumulator connection 18. The selection valve 48 comprises a first selection valve connection 48.1, which is connected to the first redundancy valve working connection 32.2, and a second selection valve connection 48.2, which is connected to the second redundancy valve working connection 46.2. The selection valve 48 is here a select high valve and controls the higher of the pressures provided at the first selection valve connection 48.1 and the second selection valve connection 48.2 at the spring accumulator connection 18. This can prevent, for example, a fixing pressure pFSprovided via the first working path 34 from being vented via the second electrically switchable redundancy valve 46 if this is in the second redundancy valve venting position 46.4 and vice versa. Spring-loaded brake cylinder 254 may thus also be ventilated with parking pressure pFSwhen second control unit 38, which actuates second electrically switchable redundancy valve 46, has a fault.In the event of a total electrical failure of the electronically controllable pneumatic brake system 200, both the first control unit 36, which is provided in the second exemplary embodiment for actuating the first electrically switchable redundancy valve 32, and the second control unit 38, which is provided in the second exemplary embodiment for actuating the second electrically switchable redundancy valve 46, have a fault. The first electrically switchable redundancy valve 32 and the second electrically switchable redundancy valve 46 then switch in each case automatically and independently of the electropneumatic parking brake valve unit 2 into their respective redundancy valve venting position 32.4, 46.4. The spring-loaded brake cylinder 254 is then vented via the first redundancy vent 24.1 and / or the second redundancy vent 24.2 in the event of a total electrical failure of the electronically controllable pneumatic brake system 200. The spring accumulator of the spring accumulator brake cylinder 254 then applies the parking brake and brakes the vehicle 300. Thus, even in the event of a total failure of the electronically controllable pneumatic brake system 200, an emergency brake function 50 can also be provided.FIG. 4 illustrates, on the basis of a block diagram, a method 400 for operating an electronically controllable pneumatic brake system 200 of a vehicle 300. The method is described herein with reference to the brake system 200 shown in FIG. 1 and comprises a total of seven steps S 1-S 7, wherein more steps or intermediate steps may also be provided and / or wherein steps S 1-S 7 may also comprise substeps.In a step S 1 of method 400, at least one redundancy switching signal SR 1 is provided at electropneumatic parking brake redundancy unit 10 of electropneumatic parking brake device 1. As shown in FIG. 1, the secondary control unit 242 can act as a first control unit 36 and provide the first redundancy switching signal SR 1 to the electropneumatic parking brake redundancy unit 10. In a second step S 2, the electropneumatic parking brake redundancy unit 10 switches into the operating position 20 in response to the provision (step S 1) of the at least one redundancy switching signal SR 1. In a third step S 3, which can also take place before the first step S 2, before the second step S 2 or simultaneously with the first step S 1 and / or the second step S 2, a parking brake signal SFB is provided at the parking brake control unit 6 of the electropneumatic parking brake valve unit 2 of the electropneumatic parking brake device 1. In the embodiment of FIG. 1, this is done by the autonomous driving unit 218. This causes an opening (step S 4) of a parking pressure pFSby the electropneumatic parking brake valve unit 2 at its working connection 8, wherein the opening takes place as a function of the parking brake signals SFBprovided at the electropneumatic parking brake valve unit 2. The parking brake redundancy unit 10 passes through the parking pressure pFS, which is controlled at the working connection 8 of the electropneumatic parking brake valve unit 2, from its redundancy supply connection 16 to its spring accumulator connection 18 (step S 5), since it was previously switched into the operating position 20. As a result, in a sixth step S 6, a spring-loaded brake cylinder 254 c, 254 d, 254 e, 254 fof the electronically switchable pneumatic brake system 200 connected to the spring-loaded connection of the electropneumatic parking brake redundancy unit 10 is ventilated. This releases the spring-loaded brakes of the vehicle 300 and the vehicle 300 is travelling.In the event of a fault, in particular a combined fault 402 of the service brake control unit 214 and the secondary control unit 242, the service brake actuators 208 a- 208 fmay no longer be used to brake the vehicle 300. In this fault case, however, neither the service brake control unit 214 nor the secondary control unit 242 can hold the electropneumatic parking brake redundancy unit 10 in the operating position 20. The electropneumatic parking brake redundancy unit 10 then switches into the venting position 22 independently of the electropneumatic parking brake valve unit 2 and in particular automatically (for example on account of a spring prestress) and thus connects the spring accumulator connection 18 to the redundancy vent 24 (step S 7). As a result, the spring-loaded brake cylinders 254 c- 254 fof the electronically switchable pneumatic brake system 200 connected to the spring-loaded connection 18 are vented and are tensioned, as a result of which an emergency braking function 50 is implemented and the vehicle 300 is braked.Reference Sign (Part of Description)1 Parking brake device 2 Parking brake valve unit 4 Supply connection 6 Parking brake control unit 8 Working connection 10 Parking brake redundancy unit 12 Parking pressure air path 16 Redundancy supply connection 18 Spring accumulator connection 20 Operating position 22 Venting position 24 Redundancy venting 24.1 First redundancy venting 24.2 Second redundancy venting 26 First electrically switchable redundancy valve 28 Second electrically switchable redundancy valve 30 Protective device 30.1 First protective connection, Parking pressure connection 30.2 Second protective connection, Operating pressure connection 30.3 Third protective connection, Protective device working connection 32 first redundancy valve 32.1 first redundancy valve supply connection 32.2 first redundancy valve working connection 32.3 first redundancy valve venting connection 32.4 first redundancy valve venting position 32.5 first redundancy valve operating position 32.6 first electromagnet 32.7 first redundancy valve signal connections 34 first working path 36 first control unit 38 second control unit 40 first shuttle valve 42 second shuttle valve 44 second working path 46 second redundancy valve 46.1 second redundancy valve supply connection 46.2 second redundancy valve working connection 46.3 second redundancy valve venting connection 46.4 second redundancy valve venting position 46.5 second redundancy valve operating position 46.6 second magnet 48 selection valve 48.1 first selection valve connection 48.2 second selection valve connection 50 emergency braking function 200 brake system 202 rear axle brake circuit 203 parking brake system 204 front axle brake circuit 206 first compressed air supply 207 trailer brake circuit 208 a- 208 fservice brake actuators 209 trailer module 210 second compressed air supply 212 service brake system 214 service brake control unit 216 vehicle bus 218 unit for autonomous driving 220 first supply line 222 first voltage source 224 first operating axle modulator 228 front axle modulator 230 operating supply connection 232.1 first service brake pressure connection 232.2 second service brake connection 234 wheel rotational speed sensor 236 second operating axle modulator 237 rear axle modulator 238 ABS valve 240 central module 241 secondary system 242 secondary control unit 244 second supply line 246 second voltage source 248 redundancy bus 250 redundancy axle modulator 252 redundancy brake pressure connection 254, 254c-254f Spring brake cylinder 256 Second redundancy signal line 264 Foot brake pedal 300 Vehicle 302 Commercial vehicle 400 Method 402 Fault HA1 First rear axle HA2 Second rear axle pB1, pB2, pB3 Service brake pressures pFS Parking pressure SA Brake request signals SB Operating brake signals SD Wheel speed signals SFB Parking brake signal SFS Parking brake signal SR Redundancy brake signals SR1 Redundancy switch signal VA Front axle S1-S7 Steps of the methodReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2021 122 497 A1

[0005] DE 10 2022 101 142 A1

[0006] DE 10 2021 122 498 A1

[0006] DE 10 2021 122 499 A1

[0006] DE 10 2020 132 875 A1

[0006] EP 3 145 769 B1

[0006]

Claims

Electropneumatic parking brake device (1) for ventilating and venting one or more spring-loaded 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) having a supply connection (4) for receiving supply pressure (pV) from a compressed air supply (210), and a parking brake control unit (6), wherein the parking brake valve unit (2) is designed to actuate a parking pressure (pFS) at at least one working connection (8) of the electropneumatic parking brake valve unit (2) as a function of a parking brake signal (SP), and an electropneumatic parking brake redundancy unit (10) having a redundancy supply connection (16), a spring accumulator connection (18) for at least indirectly connecting to a spring accumulator brake cylinder (254c, 254d, 254e, 254f) and at least one redundancy vent (24), wherein the redundancy supply connection (16) of the parking brake redundancy unit (10) is connected to the working connection (8) of the electropneumatic parking brake valve unit (2) for receiving the parking pressure (pFS), wherein the electropneumatic parking brake redundancy unit (10) has at least one operating position (20), in which the redundancy supply connection (16) is connected to the spring accumulator connection (18), and at least one vent position (22), in which the spring accumulator connection (18) is connected to the at least one redundancy vent (24), wherein the electropneumatic parking brake redundancy unit (10) can be controlled by at least one first control unit (36) for switching from the venting position (22) into the operating position (20), wherein the electropneumatic parking brake redundancy unit (10) is designed to switch into the venting position (22) independently of the electropneumatic parking brake valve unit (2) for providing an emergency braking function (50).The electropneumatic parking brake device (1) according to claim 1, wherein the electropneumatic parking brake redundancy unit (10) is designed to provide the emergency brake function (50) if the first control unit (36) has a fault.Electropneumatic parking brake device (1) according to Claim 1 or 2, wherein the electropneumatic parking brake redundancy unit (10) has at least one first electrically switchable redundancy valve (32) which, in a first redundancy valve operating position (32.5), opens up the first working path (34) connecting the redundancy supply connection (16) to the spring accumulator connection (18), with the result that the electropneumatic parking brake redundancy unit (10) is in the operating position (20); and which connects the spring accumulator connection (18) to a redundancy vent (24, 24.1) in a first redundancy valve vent position (32.4), such that the electropneumatic parking brake redundancy unit (10) is in the vent position (22), wherein the first electrically switchable redundancy valve (32) can be actuated by the first control unit (36) for switching from the first redundancy valve vent position (32.4) into the first redundancy valve operating position (32.5).Electropneumatic parking brake device (1) according to Claim 3, wherein the electropneumatic parking brake redundancy unit (10) furthermore has a second electrically switchable redundancy valve (46) which, in a second redundancy valve operating position (46.5), opens the second working path (44) connecting the redundancy supply connection (16) to the spring accumulator connection (18), with the result that the electropneumatic parking brake redundancy unit (10) is in the operating position (20); and which, in a second redundancy valve venting position (46.4), connects the spring accumulator connection (18) to a redundancy vent (24, 24.2), with the result that the electropneumatic parking brake redundancy unit (10) is in the venting position (22).The electropneumatic parking brake device (1) according to claim 4, wherein the first working path (34) and the second working path (44) of the electropneumatic parking brake redundancy unit (10) are parallel working paths (34, 44).Electropneumatic parking brake device (1) according to Claim 5, wherein the first working path (34) and the second working path (44) are connected adjacent to the spring accumulator connection (18) via a selection valve (48), wherein the selection valve (48) is designed to connect that working path (34, 44) which leads a higher pressure from the first working path (34) and the second working path (44) to the spring accumulator connection (48).Electropneumatic parking brake device (1) according to one of Claims 1 to 6, wherein the electropneumatic parking brake redundancy unit (10) can be actuated by a second control unit (38) in order to switch from the venting position (22) into the operating position (22).The electropneumatic parking brake device (1) according to claim 7, wherein the electropneumatic parking brake redundancy unit (10) is designed to provide the emergency braking function (50) if the first control unit (36) has a fault or if the second control unit (38) has a fault; and / or wherein the electropneumatic parking brake redundancy unit (10) is designed to provide the emergency braking function (50) if the first control unit (36) and the second control unit (38) have a fault.The electropneumatic parking brake device (1) according to any one of claims 1 to 8, wherein the electropneumatic parking brake valve unit (2) and the electropneumatic parking brake redundancy unit (10) are connected in series along a parking pressure air path (12).Electropneumatic parking brake device (1) according to one of Claims 1 to 9, further having a protective device (30) having a first parking pressure connection (30.1), an operating pressure connection (30.2) and a protective device operating connection (30.3), wherein the parking pressure connection (30.1) for receiving the parking pressure (pFS) is connected to the spring accumulator connection (18) of the electropneumatic parking brake redundancy unit (10), wherein the operating pressure connection (30.2) for receiving a service brake pressure (pB1, pB2, pB3) is connectable to a service brake circuit, and wherein the protective device (30) is designed to generate the higher pressure from the parking pressure (pFS) and the service brake pressure (pB1, pB2, pB3) at the protection device working connection (30.3).Electronically controllable pneumatic brake system (200) for a vehicle (300), comprising at least one parking brake actuator having a spring-loaded brake cylinder (254c, 254d, 254e, 254f), a first compressed air supply (206, 210) for providing supply pressure (pV), and an electropneumatic parking brake device (1) according to one of Claims 1 to 10, wherein the supply connection (4) of the electropneumatic parking brake valve unit (2) is connected to the first compressed air supply (206, 210), and wherein the spring-loaded connection (18) of the electropneumatic parking brake redundancy unit (10) is connected to the spring-loaded brake cylinder (254c, 254d, 254e, 254f).Electronically controllable pneumatic brake system (200) according to Claim 11, comprising an electropneumatic parking brake device (1) according to Claim 7, wherein the electropneumatic parking brake redundancy unit (10) is designed to provide the emergency brake function (50) only if the first control unit (36) and the second control unit (38) have a fault.Electronically controllable pneumatic brake system (200) according to claim 11 or 12, further 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.Electronically controllable pneumatic brake system (200) according to Claim 13, wherein the first control unit (36) can switch the electropneumatic parking brake redundancy unit (10) from the venting position (22) into the operating position (20) only if the first voltage source (222) and the second voltage source (246) provide electrical energy.The electronically controllable pneumatic brake system (200) according to any one of claims 11 to 14, further comprising an autonomous driving unit (218), wherein the autonomous driving unit (218) is the first control unit (36).Electronically controllable pneumatic brake system (200) according to one of Claims 11 to 14, further comprising at least one service brake actuator (208a, 208b, 208c, 208d, 208e, 208f) and a service brake system (212) having a service brake control unit (214) at least for actuating the at least one service brake actuator (208a, 208b, 208c, 208d, 208e, 208f), wherein the service brake control unit (214) is the first control unit (36).Electronically controllable pneumatic brake system (200) according to Claim 16, further comprising a secondary system (241) having a secondary control unit (242), wherein the secondary system (241) is designed to actuate the at least one service brake actuator (208a, 208b) if a fault is determined in the service brake system (212).Electronically controllable pneumatic brake system (200) according to claim 17, comprising an electropneumatic parking brake device (1) according to claim 7, wherein the secondary control unit (242) is the second control unit (38).Electronically controllable pneumatic brake system (200) according to Claim 15, comprising an electropneumatic parking brake device (1) according to Claim 7, furthermore having at least one service brake actuator (208a, 208b, 208c, 208d, 208e, 208f) and a service brake system (212) having a service brake control unit (214) at least for actuating the at least one service brake actuator (208a, 208b), wherein the service brake control unit (214) is the second control unit (38).Vehicle (300), in particular commercial vehicle (302), having at least one front axle (VA), at least one first rear axle (HA1) and an electronically controllable pneumatic brake system (1) according to one of the preceding claims 11 to 19.Method (400) for operating an electronically controllable pneumatic brake system (200) for a vehicle (300), which comprises a first control unit (36) and a parking brake system (203) having at least one spring-loaded brake cylinder (254c, 254d, 254e, 254f) and an electropneumatic parking brake device (1), the method (400) having the steps: - providing (S1) at least one redundancy switching signal (SR1) at an electropneumatic parking brake redundancy unit (10) of the electropneumatic parking brake device (1); - switching (S2) the parking brake redundancy unit (10) into an operating position (20) in response to the provision of the at least one redundancy switching signal (SR1); providing (S3) a parking brake signal (SFB) at a parking brake control unit (6) of an electropneumatic parking brake valve unit (2) of the electropneumatic parking brake device (1); controlling (S4) a parking pressure (pFS) by the electropneumatic parking brake valve unit (2) at a working connection (8) of the electropneumatic parking brake valve unit (2) as a function of the parking brake signal provided at the parking brake control unit (6); passing (S5) the parking pressure (pFS) controlled at the working connection (8a, 8b) from a redundancy supply connection (16) of the parking brake redundancy unit (10) to a spring accumulator connection (18) of the parking brake redundancy unit (10), venting (S6) a spring accumulator brake cylinder (254c, 254d, 254e, 254f) connected to the spring accumulator connection (18) of the parking brake redundancy unit (10); and - automatically and independently of the electropneumatic parking brake valve unit (2) switching (S7) the parking brake redundancy unit (10) from the operating position (20) into a venting position (22) in which the spring accumulator connection (18) is connected to a redundancy venting (24) of the parking brake redundancy unit (10) in order to vent the spring accumulator brake cylinder (254c, 254d, 254e, 254f) in order to provide an emergency braking function (50).

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