Reliable parking brake valve unit with one bypass valve

Description

[0001] The invention relates to an electropneumatic parking brake device for ventilating and venting one or more spring-loaded cylinders of an electronically controllable pneumatic braking system for a vehicle, comprising a parking brake valve unit with a supply connection for receiving supply pressure from a parking brake supply, wherein the parking brake valve unit controls a parking brake pressure at at least one spring-loaded connection as a function of a parking brake signal, and a check valve arranged between the parking brake valve unit and the parking brake supply (26) to prevent a backflow of compressed air from the parking brake valve unit to the parking brake supply.

[0002] The invention further relates to 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 on a front axle of the vehicle and at least one first rear axle brake actuator and one second rear axle brake actuator on a rear axle of the vehicle, as well as a primary system with a primary control unit at least for controlling the first front axle brake actuator, the second front axle brake actuator, the first rear axle brake actuator and the second rear axle brake actuator.

[0003] The invention further relates to a method for controlling an electronically controllable pneumatic braking system, comprising the steps of: controlling a parking brake valve unit by means of a parking brake control unit for pressurizing and venting at least one spring brake cylinder on a rear axle of a commercial vehicle, wherein the parking brake valve unit is connected to a parking brake reservoir via a check valve and receives reservoir pressure therefrom; and determining a fault in the electronically controllable pneumatic braking system, in particular the parking brake control unit or parking brake valve unit.

[0004] Electropneumatic valve assemblies for actuating a parking brake function are used in both Europe and the US. The parking brake function of an electropneumatic braking system typically uses so-called spring-loaded brake cylinders, which are applied by a spring force and open when ventilated. While driving, these spring-loaded brake cylinders should be ventilated and thus open, while they are vented and thus applied when the vehicle is parked.

[0005] A solution for ventilating such spring brake cylinders is disclosed in DE 10 2017 005 757 A1. The solution disclosed therein utilizes a pilot valve unit and a main valve unit, wherein the pilot valve unit comprises an electromagnetic solenoid valve in the form of a bistable valve. In the solution disclosed therein, the main valve unit is formed by a relay valve. Depending on the switching position of the electromagnetic bistable valve, a control pressure is applied to the main valve unit, which then correspondingly controls a volume pressure for the spring brake cylinders. A bistable valve is a solenoid valve that has two stable switching positions, in particular a stable ventilation position and a stable venting position.For this purpose, by energizing a first electromagnet, an armature of the solenoid valve can be moved to a first position, so that the solenoid valve assumes the ventilation position. By energizing a second electromagnet, the armature of the solenoid valve can be moved to a second position, so that the solenoid valve assumes the venting position. If no other force acts on the armature, or if it can be mechanically and / or magnetically locked in the positions, the respective switching position is stable because it can be maintained without further power supply.

[0006] A braking system with another generic parking brake device is disclosed in DE 103 36 611 A1. It discloses a pressure-operated braking system for a vehicle with a parking brake function, in which, as a result of manual actuation of an electric parking brake signal transmitter, at least one wheel brake of the braking system can be actuated without actuating a brake pedal via an actuator that can be actuated with the pressure medium. Based on this, a pressure-operated braking system for a vehicle is specified in which a parking brake function actuated via an electric signal transmitter can be integrated with minimal effort while complying with the relevant safety regulations for braking systems.This is achieved by providing a parking brake module in which an electronic control device and a valve device that can be actuated electrically by the electronic control device are integrated, wherein the electronic control device activates the parking brake function upon receipt of an electrical actuation signal from the parking brake signal generator requesting the activation of the parking brake function, wherein the electronic control device controls the pressure medium application to the actuator by means of the electrically actuated valve device as part of the parking brake function.

[0007] Furthermore, DE 10 2008 007 877 B3 discloses a parking brake device for motor vehicles with a spring-loaded brake cylinder controllable by a relay valve. The relay valve is controllable via a safety valve designed as a 3 / 2-way valve, the output of which is selectively connectable to one of two inputs. The inputs of the safety valve are connectable via a first or a second solenoid valve, optionally to a pressure medium source or atmospheric pressure. A select-low valve is connected to one input and the output of the safety valve, and an output of the select-low valve is connected to a control input of the relay valve. This is intended to improve the stability of the system.

[0008] Furthermore, DE 10 2015 008 377 A1 discloses a parking brake module with which the pressure medium supply to at least one brake actuator can be controlled. The parking brake module comprises an electronic control device, at least one solenoid valve actuatable by the control device, a pressure medium-increasing valve for supplying pressure medium to the at least one brake actuator, and at least one pressure medium inlet via which pressure medium can be supplied to the parking brake module. The parking brake module comprises an emergency release pressure medium connection and a double check valve. The parking brake module comprises a first pressure medium line, with which the emergency release pressure medium connection is fluidly connected via a check valve to the supply inlet of the pressure medium-increasing valve in such a way that pressure medium flows through this first pressure medium line from the emergency release pressure medium connection to the pressure medium-increasing valve.if the pressure at the emergency release pressure medium connection is greater than the pressure at the supply inlet of the pressure-medium-quantity-boosting valve, and the parking brake module has a second pressure medium line, with which the emergency release pressure medium connection or another pressure medium connection of the parking brake module is fluidly connected to an inlet of the double check valve in such a way that pressure medium flows through this second pressure medium line from the emergency release pressure medium connection to the double check valve if the pressure at the emergency release pressure medium connection is greater than the pressure at the inlet of the double check valve, or that pressure medium flows through this second pressure medium line from the further pressure medium connection to the double check valve if the pressure at the further pressure medium connection is greater than the pressure at the inlet of the double check valve.

[0009] Although the systems described above are advantageous and work well in practice, there is still a need to further improve the safety of such systems. In particular, even with "by-wire" controlled systems, emergency engagement of the parking brake should be possible in the event that a parking brake system or a control unit controlling the parking brake system is not functioning or is not functioning properly.

[0010] The present invention solves the problem in an electropneumatic parking brake device of the type mentioned at the outset in that a bypass valve is provided which can be switched to ventilate and vent the spring-loaded connection, wherein the bypass valve is controlled and switched independently of the parking brake valve unit.

[0011] The additional bypass valve, which is provided alongside the generally known parking brake valve unit, serves, in addition to the parking brake valve unit, to pressurize and / or vent the spring-loaded connection and can be controlled and switched independently of the parking brake valve unit. The bypass valve thus forms a bypass to the parking brake valve unit and can be switched either to pressurize and / or vent the spring-loaded connection in the event that the parking brake valve unit is not functioning or is not functioning properly, or cannot be controlled or cannot be controlled properly. In this respect, the invention is based on the idea that the bypass valve can be controlled and switched independently of the parking brake valve unit.

[0012] It has been shown that in electropneumatic parking brake systems in which a check valve is arranged between the parking brake valve unit and the parking brake supply to prevent compressed air from flowing back from the parking brake valve unit to the parking brake supply, emergency engagement of the spring brake cylinders connected to the spring brake connection "by wire" is difficult or even impossible. Typical routines for emergency engagement of spring brake cylinders in such electropneumatic parking brake systems involve lowering the supply pressure of the parking brake supply, a so-called "pumping down" process, in order to reduce the pressure that can usually be supplied to the spring brake cylinders. If the supply pressure, from which the working pressure for the spring brake cylinders is fed, drops, the spring brake cylinders automatically apply, as they are applied by the force of the springs.However, if a check valve is provided, compressed air cannot flow back from the parking brake valve unit to the parking brake reservoir, and therefore pressure equalization from the spring brake cylinder to the reduced compressed air reservoir cannot take place. This means that regardless of the level in the compressed air reservoir, the spring brake cylinders remain released because the pressure prevailing in them is trapped by the check valve. Bleeding the spring brake cylinders and thus engaging them is only possible if the parking brake valve unit is switched to a bleed position. However, this is not possible in the event of a fault in the parking brake valve unit or an electronic control unit that controls it. Consequently, in these cases, the spring brake cylinders must be engaged manually, for example by manually bleeding the spring brake cylinders.

[0013] The invention offers a remedy here by providing a bypass valve, which can preferably be switched both for venting and for bleeding the spring-loaded connection, independently of the parking brake valve unit. Therefore, if the parking brake valve unit is not functioning or is not functioning properly, or cannot be controlled or cannot be controlled correctly, the bypass valve unit can be switched manually or automatically to vent the spring-loaded connection and, subsequently, the spring-loaded brake cylinders connected to it. This allows emergency engagement of the spring-loaded brake cylinders even if the parking brake valve unit is not functioning or is not functioning properly, or cannot be controlled or cannot be controlled correctly.In the opposite case, if the spring brake cylinders are not vented and thus released, or are not working properly, the bypass valve can be switched to vent the spring brake connection and thus release the spring brake cylinders connected to it.

[0014] The bypass valve can comprise one or more switchable electromagnetic valves, which can be designed more cost-effectively than valves in the parking brake valve unit. The bypass valve is used to vent or pressurize the spring-loaded connection only in the event of a parking brake valve unit failure and is therefore only used very rarely during vehicle operation. Its sole purpose is to enable fail-safe operation, thus providing a level of redundancy for the parking brake valve unit.

[0015] In a preferred embodiment, the bypass valve is electromagnetic and can be controlled by an additional electronic control unit that is independent of the parking brake valve unit. The parking brake valve unit is preferably controlled by a parking brake control unit, which can be part of the electropneumatic parking brake device. The parking brake control unit can be integrated with the parking brake valve unit to form a module. The parking brake control unit can have its own intelligence or only comprise output stages that are electrically connected to a higher-level control unit. The additional electronic control unit that controls the bypass valve is different from the parking brake control unit. The additional electronic control unit is preferably a control unit already present in the electronically controllable pneumatic brake system, or a control unit provided separately for the bypass valve.However, it is particularly efficient and space-saving if a control unit already present in the electronically controllable pneumatic brake system is used to control the bypass valve. This ensures that, in the event of a fault in the parking brake control unit, the bypass valve can still be controlled and switched by the additional control unit to pressurize or vent the spring-loaded connection.

[0016] The electropneumatic parking brake device preferably has a bypass pressure sensor for detecting the parking brake pressure applied at the spring-loaded connection. The bypass pressure sensor is connected to the additional electronic control unit, which is independent of the parking brake valve unit. In this way, the additional electronic control unit can evaluate the pressure applied at the spring-loaded connection and actuate the bypass valve accordingly. This allows for regulation of the parking brake pressure.

[0017] Furthermore, it is preferred that the bypass valve is monostable and can assume a blocking position as well as a passing position, wherein the bypass valve is stable in the blocking position. In this case, the bypass valve can be designed, for example, as a 2 / 2-way valve and can be switched into the blocking position under spring load. Only when energized is the bypass valve then switched to the passing position, in which the spring-loaded connection can be ventilated or vented. To achieve this with a 2 / 2-way valve, the 2 / 2-way valve designed as a bypass valve is preferably connected to the spring-loaded connection via a first bypass valve connection and to the parking brake supply via a second bypass valve connection, or to a supply pressure line that runs between the parking brake supply and the check valve, so that the bypass valve bypasses the check valve.If the parking brake supply is now carrying compressed air and can provide a sufficiently high pressure, the spring-loaded connection can be vented by switching the bypass valve to the open position, bypassing the check valve and the parking brake valve unit. If the parking brake supply is largely or completely depressurized (for example, due to pumping down) due to a fault or a fault-resolution routine, the spring-loaded connection can be connected to the then depressurized parking brake supply by switching the bypass valve to the open position, bypassing the parking brake valve unit and the check valve, so that the spring-loaded connection can be vented in this case.

[0018] According to a further preferred embodiment, the bypass valve has a first bypass valve connection connected to the spring-loaded connection or to a main valve unit upstream of the spring-loaded connection, and a second bypass valve connection connected to a vent. Alternatively, the bypass valve has a first bypass valve connection connected to the spring-loaded connection or to a main valve unit upstream of the spring-loaded connection, and a second bypass valve connection connected to the parking brake supply upstream of the check valve. The second bypass valve connection can therefore be connected either to a vent or to the parking brake supply. This is particularly preferred if the bypass valve is designed as a 2 / 2-way valve, as described above.If the second bypass valve port is only connected to the vent, the spring-loaded port can only be vented through the bypass valve in the open position. However, if the second bypass valve port is connected to the parking brake reservoir, the spring-loaded port can be vented when the parking brake reservoir has sufficient pressure and vented when the parking brake reservoir is depleted.

[0019] According to a preferred development, the bypass valve is designed with the parking brake valve unit as a single structural unit. The bypass valve can be housed with the parking brake valve unit in a modular housing or simply flanged to the parking brake valve unit or formatted with it. This is particularly advantageous because it reduces assembly effort and allows for compact components. Furthermore, interfaces between individual elements can be reduced, eliminating lines that might otherwise be prone to leakage.

[0020] Preferably, the bypass valve is directly connected to a parking brake pressure line connected downstream of the spring-loaded brake connection. This design is particularly advantageous when the bypass valve is external to the parking brake valve unit, for example, flanged to it or arranged outside a module housing, or represented as a separate component. The direct connection of the bypass valve to a parking brake pressure line connected downstream of the spring-loaded brake connection, which in turn leads to the spring-loaded brake cylinder, can lead to direct venting or ventilation of the spring-loaded brake cylinder. It is also conceivable for the bypass valve to be connected directly to the spring-loaded brake cylinder.

[0021] In a preferred embodiment, the parking brake valve unit comprises a pilot valve unit and a main valve unit. Such a design is essentially known in the prior art. In such a design, the pilot valve unit is provided to provide a parking brake control pressure to the main valve unit, which then controls the parking brake pressure at the spring-loaded connection depending on the received parking brake control pressure. For this purpose, the main valve unit is generally designed to be volume-increasing and can, for example, comprise a relay valve or a pneumatically switchable main valve. Such designs allow for more efficient air utilization, since when the parking brake pressure varies, only the parking brake control pressure, which has a lower volume, needs to be vented, so that overall air consumption can be reduced.

[0022] The bypass valve is preferably connected to the main valve unit, wherein the parking brake control pressure can be vented via the bypass valve. In this way, the bypass valve is preferably connected to the main valve unit via the same line via which the pilot valve unit is connected to the main valve unit. The main valve unit is preferably designed to be purely pneumatic and can therefore switch independently of a parking brake control unit and independently of a power source. In the event that the pilot valve unit is not functioning or is not functioning properly, the parking brake control pressure can be vented via the bypass valve, so that the spring-loaded connection is subsequently also vented.

[0023] In a preferred development, the bypass valve is connected to a bypass branch line that branches off from a parking brake control pressure line, via which the parking brake control pressure is supplied to the main valve unit by the pilot valve unit. In a further preferred embodiment, a first shuttle valve is provided in the parking brake control pressure line, which first shuttle valve has a first shuttle valve connection connected to the pilot valve unit, a second shuttle valve connection connected to an anti-compound connection, and a third shuttle valve connection connected to the main valve unit. The first shuttle valve is preferably designed such that the higher pressure present at the first shuttle valve connection and the second shuttle valve connection is controlled at the third shuttle valve connection.This design allows either the parking brake control pressure supplied by the pilot valve unit or a pressure supplied via the anti-compound port to be controlled at the main valve unit.

[0024] An anti-compound connection is used primarily to prevent overloading of brake actuators. In most brake systems, so-called Tristop cylinders, which can function as both service brake cylinders and parking brake cylinders, are connected to the spring-loaded connection. If the spring-loaded portion of the Tristop cylinder is vented to activate the parking brake function, the service brake portion of the Tristop cylinder may also be activated, for example, if a vehicle operator presses the brake pedal. In this case, both the spring-loaded portion and the service brake portion would exert a force, which could lead to component overloading.With a so-called anti-compound function, the service brake pressure applied to the Tristop cylinder is simultaneously fed to the parking brake system via the anti-compound connection, which then applies parking brake pressure to the spring-loaded connection to similarly pressurize and thus release the spring-loaded part of the Tristop cylinder. This means that in the same way that the service brake component exerts a force, the force exerted by the spring-loaded part is reduced.

[0025] It is further preferred that the bypass branch line branches off between the first shuttle valve port and the pilot valve unit. The bypass valve should be designed so that it can vent the parking brake control pressure, and not the anti-compound pressure provided at the anti-compound port. The anti-compound function thus remains independent of the bypass valve's switching.

[0026] In a preferred embodiment, it is further provided that the parking brake valve unit has a compensation valve, which is designed to maintain a parking brake control pressure controlled by the pilot valve unit at the main valve unit and thus at least partially compensate for a leak in the pilot valve unit and / or the main valve unit. The compensation valve can advantageously compensate for leaks that occur in the pilot valve unit and / or the main valve unit. This is advantageously made possible by a controllable pneumatic connection to the parking brake supply or to a vent connection, which can be established by the compensation valve.

[0027] The compensation valve is preferably designed as a pneumatically switchable 3 / 2-way valve and has a first compensation valve connection connected to the check valve, a second compensation valve connection connected to a line carrying the parking brake control pressure, and a third compensation valve connection connected to a vent. Preferably, the compensation valve is spring-loaded into a first switching position, in which the second compensation valve connection is connected to the third compensation valve connection. If a compensation valve control pressure provided at a compensation valve control connection exceeds a compensation valve threshold, it switches to a second switching position, in which the first compensation valve connection is connected to the second compensation valve connection.It is further preferred that the compensation valve control pressure is a pressure applied or controlled at the second compensation valve connection, thereby realizing pneumatic self-locking for the compensation valve. The compensation valve preferably has a return spring that biases the compensation valve into the first switching position. Advantageously, the compensation valve is designed, in particular by designing one or more of the return springs, to switch to the second switching position when the compensation valve threshold is exceeded. Advantageously, the compensation valve threshold lies in a range between 0.241 MPa (35 psi) and 0.379 MPa (55 psi), preferably between 0.276 MPa (40 psi) and 0.345 MPa (50 psi), and is preferably 0.310 MPa (45 psi).

[0028] It is advantageously provided that the second compensation valve connection is pneumatically connected to the compensation valve control connection via a compensation control path.

[0029] In an advantageous development, the compensation valve is designed to be throttled, preferably such that the connection between the first compensation valve connection and the second compensation valve connection and / or the connection between the second compensation valve connection and the third compensation valve connection is throttled in each case. In particular, the compensation valve has a first throttle for throttling the pneumatic connection between the first compensation valve connection and the second compensation valve connection in the second switching position. In particular, the second compensation valve has a second throttle for throttling the pneumatic connection between the second compensation valve connection and the third compensation valve connection in the first switching position.In other developments, a common throttle can be provided which is independent of the switching position of the compensation valve and is connected upstream or downstream of the compensation valve. Such a common throttle can advantageously be arranged between the second compensation valve connection and a branch node for the compensation control path. In a particularly preferred embodiment, it is provided that the parking brake valve unit and the bypass valve are supplied with electrical voltage from two independent voltage sources. Preferably, the further electronic control unit is also supplied by the voltage source that also supplies the bypass valve. In this way, safety can be increased and fail-operational operation can be enabled in a braking system that has two independent voltage sources.

[0030] In a second aspect, the invention achieves the object mentioned at the outset in an electronically controllable pneumatic braking system in that it has an electropneumatic parking brake device according to one of the above-described preferred embodiments of an electropneumatic parking brake device according to the first aspect of the invention, wherein at least one first spring-loaded cylinder on the rear axle is connected to the at least one spring-loaded connection and wherein the bypass valve is switchable for ventilating and venting the first spring-loaded cylinder, wherein the bypass valve is controlled and switched independently of the parking brake valve unit.

[0031] It should be understood that the electropneumatic parking brake device according to the first aspect of the invention and the electronically controllable pneumatic braking system according to the second aspect of the invention have identical and similar sub-aspects, as particularly set forth in the dependent claims. Reference is therefore made in full to the above description, and preferred embodiments, features, and advantages are also to be considered in the second aspect of the invention and incorporated by reference.

[0032] In a preferred embodiment of the electronically controllable pneumatic brake system, the parking brake valve unit is connected to a parking brake control unit and receives switching signals therefrom, wherein the bypass valve is connected to a further control unit independent of the parking brake valve unit and receives at least one bypass switching signal therefrom. Preferably, the parking brake control unit is connected to a first voltage source and is supplied with electrical voltage by this, and the further electronic control unit is connected to a second voltage source and is supplied with electrical voltage by this. The further electronic control unit is preferably a control unit present in the electronically controllable pneumatic brake system, such as the primary control unit. The primary control unit is typically independent of the parking brake control unit.In some concepts, the parking brake control unit forms a fallback level and thus also a secondary control unit for the first redundancy level of the electronically controllable pneumatic braking system. In the event that this redundancy level fails, for example due to the parking brake control unit failing, the primary control unit can control the bypass valve and thus vent the spring brake cylinders or ventilate the spring brake cylinders. In the event that the parking brake valve unit is assigned to the primary control unit, the bypass valve is preferably controlled by another control unit, such as another secondary control unit that is provided independently of the primary control unit.

[0033] In a preferred development of the electronically controllable pneumatic brake system, it further comprises a secondary system with a secondary control unit, at least for controlling the first front axle brake actuator, the second front axle brake actuator, the first rear axle brake actuator, and the second rear axle brake actuator. In the event that a fault is detected in the primary system, the electronically controllable pneumatic brake system is controlled at least partially by the secondary system. In this case, the secondary system forms a first fallback level. It can be provided that the secondary system can completely replace the primary system and, to that extent, the secondary control unit can also completely replace the functionality of the primary control unit.It may also be provided that the secondary control unit has only a limited range of functions of the primary control unit and therefore does not have full functionality, but sufficient functionality to carry out a "limp-home maneuver" in particular.

[0034] In this variant, it can also be provided that the secondary control unit forms or comprises the additional control unit that controls the bypass valve. In this case, the bypass valve can then be controlled by the secondary control unit in the event that the primary control unit is not functioning or is not functioning properly and the parking brake control unit is also not functioning or is not functioning properly.

[0035] Other control units, such as a control unit of an electronic steering system, a control unit of a trailer control module, a control unit of an air suspension, or other control units, can also preferably be provided within the scope of the invention as additional control units for controlling the bypass valve. For this purpose, it is then preferred that the respective control unit is connected to a BUS system or communicates with a higher-level control unit in such a way that the additional control unit is capable of controlling switching signals for the bypass valve.

[0036] In a third aspect, the object mentioned above is achieved by a vehicle, in particular a commercial vehicle, having a front axle, at least one first rear axle, and an electronically controllable pneumatic braking system according to a preferred embodiment of the electronically controllable pneumatic braking system according to the second aspect of the invention described above. It should be understood that the vehicle according to the third aspect of the invention, the electronically controllable pneumatic braking system according to the second aspect of the invention, and the electropneumatic parking brake device according to the first aspect of the invention have the same and / or similar sub-aspects, as set out in particular in the dependent claims.In this respect, for further developments of the vehicle according to the third aspect of the invention, reference is made in full to the electronically controllable pneumatic braking system according to the second aspect of the invention and the electropneumatic parking brake device according to the first aspect of the invention.

[0037] In a fourth aspect of the invention, the object mentioned at the outset is also achieved by a method for controlling an electronically controllable pneumatic brake system, preferably an electronically controllable pneumatic brake system according to one of the preferred embodiments described above according to the second aspect of the invention.The method preferably comprises the steps of: controlling a parking brake valve unit by means of a parking brake control unit for venting and bleeding at least one spring brake cylinder on a rear axle of a commercial vehicle, wherein the parking brake valve unit is connected to a parking brake reservoir via a check valve and receives reservoir pressure from this; determining a fault in the electronically controllable pneumatic brake system, in particular the parking brake control unit and / or the parking brake valve unit; switching a bypass valve, which is connected to both the at least one spring brake cylinder and the parking brake reservoir, into a venting position for venting the at least one spring brake cylinder; wherein the bypass valve switches in response to a bypass switching signal provided by a further electronic control unit that is independent of the parking brake control unit.

[0038] It should be understood that the electropneumatic parking brake device according to the first aspect of the invention, the electronically controllable pneumatic braking system according to the second aspect of the invention, the vehicle according to the third aspect of the invention, and the method for controlling an electronically controllable pneumatic braking system according to the fourth aspect of the invention have the same and similar sub-aspects, as set out in particular in the dependent claims. Therefore, for further developments of the method for controlling an electronically controllable pneumatic braking system, reference is made in full to the further embodiments, advantages, and features of the first three aspects of the invention.

[0039] In a preferred development of the method, it is provided that the parking brake control unit is connected to a first voltage source and is supplied with electrical voltage by this, and the further control unit is connected to a second voltage source and is supplied with electrical voltage by this.

[0040] Preferably, the method further comprises the step of: lowering the reservoir pressure in the parking brake reservoir to vent the at least one spring brake cylinder.

[0041] 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.

[0042] Further advantages, features and details of the invention will become apparent from the following description of the preferred embodiments and from the drawings, which show: Fig. 1 shows a first embodiment of an electropneumatic parking brake device; Fig. 2 shows a commercial vehicle with an electronically controllable pneumatic braking system and an electropneumatic parking brake device; Fig. 3 shows a second embodiment of an electropneumatic parking brake device; Fig. 4 shows a third embodiment of an electropneumatic parking brake device; Fig. 5 shows a second embodiment of a commercial vehicle with an electronically controllable pneumatic braking system and an electropneumatic parking brake device; Fig. 6 shows a fourth embodiment of an electropneumatic parking brake device; and Fig. 7 shows a fifth embodiment of an electropneumatic parking brake device.

[0043] An electropneumatic parking brake device 1 can, in a first embodiment ( Fig. 1 ) be designed as a parking brake module 2. For this purpose, it has a module housing 4, on which a supply connection 6, a vent connection 3 as well as a first spring-loaded connection 8 and a second spring-loaded connection 9 are arranged. The electropneumatic parking brake device 1 also comprises a parking brake control unit 10 and a parking brake valve unit 24, which is controlled by the parking brake control unit 10. The parking brake valve unit 24 is basically formed as known in the prior art and is connected both to the supply connection 6 and to the first and second spring-loaded connections 8, 9. The parking brake valve unit 24 receives supply pressure pV from the supply connection 6 and controls a parking brake pressure pBP at the first and second spring-loaded connections 8, 9 depending on the first and second switching signals S1, S2, which are provided by the parking brake control unit 10.The first and second switching signals S1, S2 are provided by the parking brake control unit 10 based on the receipt of a parking brake signal SP. The parking brake signal SP is provided by a higher-level unit, as described below with reference to FIG. Fig. 2 will be described in more detail. It can also be provided that the parking brake signal SP is provided directly at the parking brake valve unit 24, and in this respect, the electropneumatic parking brake device 1 does not have its own parking brake control unit 10, but is directly wired.

[0044] Specifically, the parking brake valve unit 24 in the embodiment shown here has a pilot valve unit 32 and a main valve unit 34, as is generally known. In the embodiment shown here, the pilot valve unit 32 comprises a bistable valve 12 with a first bistable valve connection 12.1 connected to the supply connection 6, a second bistable valve connection 12.2, and a third bistable valve connection 12.3 connected to the vent connection 3. More precisely, the first bistable valve connection 12.1 is initially connected to a check valve 30, which is integrated into the module housing 4 here and is connected upstream of the parking brake valve unit 24. The check valve 30 serves to prevent pressure from flowing from the parking brake valve unit 24 toward the supply connection 6. Supply pressure pV is therefore only supplied from the supply pressure 6 via the check valve 30 to the first bistable valve connection 12.1 is provided, but pressure equalization cannot take place in reverse.

[0045] The second bistable valve connection 12.2 is connected here to a holding valve 14, which is designed as a 2 / 2-way valve. The holding valve 14 has a first holding valve connection 14.1 and a second holding valve connection 14.2. The holding valve 14 is designed as a 2 / 2-way valve and is monostable. It is biased in an open position and can be switched to a blocking position (in Fig. 1 not shown). The first holding valve port 14.1 is connected to the bistable valve 12, more precisely to the second bistable valve port 12.2. The second holding valve port 14.2 is connected to the main valve unit 34. The bistable valve 12 and the holding valve 14 together form the pilot valve unit 32. It should be understood that the holding valve 14 can also be omitted. The pilot valve unit 32 controls a parking brake control pressure pPS at the main valve unit 34 when the bistable valve 12 and the holding valve 14 are switched accordingly. In the embodiment shown here, the main valve unit 34 comprises a relay valve 16, which has a relay valve supply connection 16.1 connected to the supply connection 6, a relay valve working connection 16.2 connected to the first and second spring-loaded connections 8, 9, and a relay valve vent connection 16 connected to the vent connection 3.3 and a relay valve control port 16.4 connected to the pilot valve unit 32. The pilot valve unit 32 provides the parking brake control pressure pPS at the relay valve control port 16.4, wherein the relay valve 16 then volume-amplifies the parking brake control pressure pPS and outputs it as the parking brake pressure pBP at the relay valve working port 16.2. For this purpose, the relay valve 16 receives the supply pressure pV from the supply port 6. It should be understood that other volume-amplifying valves, such as a pneumatic switching valve, can also be used instead of the relay valve 16.

[0046] In the concrete in Fig. 1 In the embodiment shown, a shuttle valve 60 is also provided between the holding valve 14 and the relay valve 16. The shuttle valve 60 has a first shuttle valve connection 60.1, which here is specifically connected to the pilot valve unit 32, namely in particular the second holding valve connection 14.2. The shuttle valve 60 has a second shuttle valve connection 60.2, which here is connected to an anti-compound connection 62, and a third shuttle valve connection 60.3, which is connected to the relay valve control connection 16.4. The shuttle valve 60 is designed such that the higher of the pressure applied to the first shuttle valve connection 60.1 and the second shuttle valve connection 60.2 is controlled at the third shuttle valve connection 60.3. Both the shuttle valve 60 and the anti-compound connection 62 are optional and can be omitted together.

[0047] By appropriately providing the parking brake signal SP, the parking brake pressure pBP can be controlled at the first and second spring-loaded connections 8, 9 or these can be vented. As a result, the spring-loaded brake cylinders connected to the first or second spring-loaded connection 8, 9 can be released or applied. When the vehicle is parked, spring-loaded brake cylinders should always be applied so that unintentional rolling away of the vehicle can be prevented. When driving, however, the spring-loaded brake cylinders are released and vented. If a fault occurs in the parking brake system, and in particular a fault in the parking brake control unit 10 or the pilot valve unit 32, a problem-solving strategy for releasing the spring-loaded brake cylinders orto vent the first and second spring-loaded connections 8, 9 and subsequently apply the spring-loaded brake cylinders, to empty the corresponding parking brake supply connected to the supply connection 6, known in technical terms as "pumping down". However, if a check valve 30 is provided, as in the present case, even if the parking brake supply is pumped down, the first and second spring-loaded connections 8, 9 cannot be vented, since pressure equalization from the parking brake valve unit 24 in the direction of the supply connection 6 is prevented by the check valve 30. This is where the invention comes in and solves this problem by means of a bypass valve 50. The bypass valve 50 forms a bypass to the parking brake valve unit 24 and is in the form shown in . Fig. 1 shown first embodiment is integrated into the module housing 4 and thus shown as a module together with the parking brake valve unit 24.

[0048] The bypass valve 50 is designed in the first embodiment as a 2 / 2-way valve and has a first bypass valve connection 50.1, which is connected to the first and second spring-loaded connections 8, 9. Specifically, the first bypass valve connection 50.1 is connected to a bypass branch line 56, which branches off from a parking brake pressure line 54, which connects the first and second spring-loaded connections 8, 9 to the relay valve working connection 16.2. The second bypass valve connection 50.2 is connected to the supply connection 6, specifically to a bypass supply node 51, which is located in the Fig. 1 shown embodiment lies between the supply connection 6 and the check valve 30. The bypass supply node is connected to a bypass supply line 53, which leads to the second bypass valve connection 50.2. The bypass valve 50 is in a blocking position in a first switching position 50A and in a passing position in a second switching position 50B. When de-energized, the bypass valve 50 is in the blocking position 50A and is also spring-loaded into this position. As soon as a bypass switching signal SB is provided to the bypass valve 50, it is energized and switched to the Fig. 1 not shown. In the pass position 50B, the first is connected to the second bypass valve connection 50.1, 50.2 and supply pressure pV can be provided via the bypass supply line 53, the bypass valve 50 as well as the bypass branch line 56 and the parking brake pressure line 54 to the first and second spring-loaded connections 8, 9, so that the spring-loaded brake cylinders connected to them can be vented. However, if the parking brake supply connected to the supply connection 6 is emptied or pumped down, the first and second spring-loaded connections 8, 9 can be vented by switching the bypass valve 50 to the pass position 50B, by pneumatically connecting them via the bypass valve 50 to the vented supply connection 6. The bypass switching signal SB is as in Fig. 1 shown, it is not provided by the parking brake control unit 10, but rather by another electronic control unit that is independent of the parking brake control unit 10, as will be described in more detail below. In this way, even in the event of a fault in the parking brake control unit 10, the first and second spring-loaded connections 8, 9 can be both vented and ventilated.

[0049] A bypass pressure sensor 52 measures the pressure present at the first bypass valve port 50.1, i.e., the pressure delivered to the first and second spring-loaded ports 8, 9. The bypass pressure sensor 52 provides a bypass pressure signal SDB, not to the parking brake control unit 10, but also to the additional electronic control unit, which also provides the bypass switching signal SB. In this way, the pressure delivered to the first and second spring-loaded ports 8, 9 can be regulated when this pressure is delivered via the bypass valve 50.

[0050] Fig. 2 now illustrates a vehicle 200, namely in particular a commercial vehicle 202, with a first axle A1, which here is a front axle VA, a second axle A2, which here is a first rear axle HA1, and a third axle A3, which here is a second rear axle HA2. The vehicle 200 comprises an electronically controllable pneumatic braking system 204, which comprises an operating level B1 and a first redundancy level B2.

[0051] At operating level B1, the electronically controllable pneumatic braking system 204 comprises a primary control unit 400, also referred to as a central module, which is connected to an autonomous driving unit 208 via a vehicle bus 206 and receives braking request signals SBA from the latter. The electronically controllable pneumatic braking system 204 comprises two independent voltage sources, namely a first voltage source 212 and a second voltage source 210, the first voltage source supplying the electropneumatic parking brake device 1, as described in detail later. The primary control unit 400 is supplied with electrical energy by a second voltage source 210.

[0052] On the front axle VA, the electronically controllable pneumatic braking system 204 comprises a front axle modulator 220, which is designed here as a single-channel modulator and receives supply pressure pV from a first compressed air supply 7. For this purpose, the front axle modulator 220 comprises, in a known manner, a front axle supply connection 222, which is piped to the first compressed air supply 7. The front axle modulator 220 is connected to the primary control unit 400 via a front axle signal line 224 and receives front axle brake signals SBV from the primary control unit 400, which cause one or more electromagnetic valves (not shown) of the front axle modulator 220 to switch, as a result of which the front axle modulator 220 controls a front axle service brake pressure pBVA, which is controlled via first and second ABS valves 226, 227 in a wheel-appropriate manner at a first front axle service brake actuator 228a and a second front axle service brake actuator 228b.The front axle signal line 224 can be implemented as a direct wiring of the electromagnetic valves of the front axle modulator 220 to the primary control unit 400, so that output stages for the electromagnetic valves of the front axle modulator 220 are preferably integrated into the central control unit 400. Alternatively, the front axle signal line 224 can also be designed as a BUS connection (CAN-BUS), particularly if the front axle modulator 220 has its own intelligence.

[0053] The electronically controllable pneumatic braking system 204 also includes a rear axle modulator 230, which is integrated here into the primary control unit 400. The rear axle modulator 230 receives supply pressure pV from a second compressed air supply 11. The primary control unit 400 converts the brake request signals SBA received via the vehicle bus 206 into rear axle brake signals SBH and switches one or more electromagnetic valves of the rear axle modulator 230 (not shown in detail here), thereby generating a rear axle service brake pressure pBHA, which is controlled by first and second rear axle service brake actuators 232a, 232b on the first rear axle HA1 and by third and fourth rear axle service brake actuators 232c, 232d on the second rear axle HA2. The rear axle service brake pressure pBHA is controlled laterally and in this respect the rear axle modulator 230 is a two-channel modulator.

[0054] In addition, the electronically controllable pneumatic brake system 204 shown here comprises an electropneumatic parking brake device 1 according to the invention, which is designed here as a parking brake module 2 and is also connected to the vehicle bus 206 and the first voltage source 212, and receives electrical energy from it. The electropneumatic parking brake device 1 is connected to a parking brake reservoir 26 and receives reservoir pressure pV from it. The electropneumatic parking brake device 1 is provided to control a parking brake pressure pBP via the first and second spring-loaded brake connections 8, 9 to first and second spring-loaded brake cylinders 242a, 242b on the first rear axle HA1 and to third and fourth spring-loaded brake cylinders 242c, 242d on the second rear axle HA2.

[0055] The electronically controllable pneumatic braking system 204 is also intended to supply a trailer and, for this purpose, has a trailer control unit 250, which also receives supply pressure pV from both the first compressed air supply 6 and the second compressed air supply 7. The trailer control unit 250 is connected to the primary control unit 400 and receives trailer brake signals SBT from it via a trailer signal line 252. In this respect, the trailer control unit 250 is also supplied by the first voltage source 210. Depending on the received trailer brake signal SBT, the trailer control unit 250 controls a trailer brake pressure pBT at a trailer brake pressure connection 251. The trailer brake signal SBT can be used, for example, to transmit a normal service brake signal, an anti-theft brake signal for implementing an anti-theft brake function, or a trailer parking signal for parking the trailer.

[0056] To form a first redundancy level B2, which in this case is electrically implemented, the electronically controllable pneumatic brake system 204 comprises a secondary control unit 402, into which one or more electromagnetic valves (not shown here) are also integrated. The secondary control unit 402 is connected to the first compressed air supply 7 and receives supply pressure pV therefrom. The secondary control unit 402 is also connected to the vehicle bus 206 and receives brake request signals SBA via it. In the exemplary embodiment shown here, it is supplied, like the electropneumatic parking brake device 1, by the first voltage source 212, which is independent of the second voltage source 210.The secondary control unit 402 is capable of processing the brake request signals SBA and controlling a working valve arrangement integrated therein in order to control a first redundancy brake pressure pR1 at a first redundancy brake pressure connection 404 and a second redundancy brake pressure pR2 at a second redundancy brake pressure connection 406. The first redundancy brake pressure pR1 is provided here to the front axle VA, and the second redundancy brake pressure pR2 is provided here to the rear axle HA1, HA2. More precisely, the first redundancy brake pressure pR1 is controlled in a basically known manner via a front axle shuttle valve 254 at a front axle redundancy connection 256 of the front axle modulator 220. The front axle modulator 220 then converts the first redundancy brake pressure pR1 received thereat and, based thereon, redundantly controls the front axle brake pressure pBVA.For this purpose, the front axle modulator 220 can, in a basically known manner, have a monostable redundancy valve and a relay piston or a pneumatically switchable main valve to control the first redundancy brake pressure pR1 provided at the front axle redundancy connection 256 with increased volume. The first redundancy brake pressure pR1 is also controlled at a trailer redundancy connection 253 to enable redundant braking of a trailer.

[0057] In a corresponding manner, the rear axle modulator 230 or the primary control unit 400, into which the rear axle modulator 230 is integrated, has a rear axle redundancy connection 258, to which the second redundancy brake pressure pR2 can be provided via a rear axle shuttle valve 260. The secondary control unit 402 thus controls the first and second redundancy brake pressures pR1, pR2 in a manner appropriate to the axles and can thus be referred to as a dual-channel modulator. The primary control unit 400 is designed to control the rear axle brake pressure pBHA based on the received second redundancy brake pressure pR2. For this purpose, the primary control unit 400 can, in a basically known manner, again have a redundancy valve and a relay piston or a pneumatically switchable main valve in order to control the second redundancy brake pressure pR2 with volume amplified as the rear axle brake pressure pBHA.In this way, an electronically controllable fallback level, in this case the first redundancy level B2, can be provided.

[0058] The Fig. 2 The electronically switchable pneumatic brake system 204 shown furthermore has a manually actuated redundancy level B3, which in the exemplary embodiment shown here comprises a foot brake pedal 262. A foot brake pressure pBF can be controlled via the foot brake pedal 262 at both the front axle shuttle valve 254 and the rear axle shuttle valve 260. The front and rear axle shuttle valves 254, 260 are each designed such that they control the higher of the applied foot brake pressure pBF and the first and second redundancy pressures pR1, pR2 to the front axle modulator 220 and the rear axle modulator 230, respectively. In this way, for example, the controlled first and second redundancy brake pressures pR1, pR2 can be overridden by actuating the foot brake pedal 262. Conversely, the secondary brake module 402 can also override the foot brake pressure pBF applied by a driver.

[0059] Both in the operating mode and in the redundancy mode, when control of the electronically controllable pneumatic brake system 204 is taken over by the secondary control unit 402, the electropneumatic parking brake device 1 or the parking brake module 2 should function. It can receive parking brake signals SP via the vehicle bus 206 and thus pressurize and vent the spring brake cylinders 224a - 224d. If this is not possible, this can be achieved according to the invention via the bypass valve 50 (see FIG. Fig. 1 ). The bypass valve 50 is connected via a bypass signal line 266 to the primary control unit 400, which in the embodiment shown here ( Fig. 2 ) forms the further electronic control unit 40. The further electronic control unit 40 can provide the bypass signal SB to switch the bypass valve 50. The further electronic control unit 40 is supplied with electrical voltage from the second voltage source 210, so that the bypass valve 50 can be switched even if, for example, the first voltage source 212 has failed and, as a result, the electropneumatic parking brake device 1 does not function or no longer functions properly, in particular the parking brake valve unit 24 and / or the parking brake control unit 10 does not function or does not function properly. In the exemplary embodiment shown here ( Fig. 2 ), the secondary control unit 402 is connected to the first voltage source 212. If, for example, it is connected to a third independent voltage source, the secondary control unit 402 could also function as a further electronic control unit 40. Within the scope of the invention, it is always preferred that the further electronic control unit 40, regardless of its location in the braking system 204, is supplied by a voltage source that is not the voltage source to which the parking brake valve unit 24 and / or parking brake control unit 10 is connected. The bypass sensor 250 also provides the bypass pressure signal SDB via the bypass signal line 266 to the further electronic control unit 40 - here primary control unit 400. This can also provide the bypass pressure signal SDB to other units in the braking system or higher-level units via the vehicle bus 206.

[0060] The Fig. 3 and 4now show a second and a third embodiment of the electropneumatic parking brake device 1 according to the first embodiment ( Fig. 1 ), which in turn is designed as a parking brake module 2 and wherein the bypass valve 50 is integrated into the parking brake module 2, namely in a common module housing 4. In the following, in particular, the differences to the first embodiment ( Fig. 1 ). Identical and similar elements are provided with the same reference numerals, so that reference is made to the above description in its entirety.

[0061] In the Fig. 3 In the embodiment shown, the pilot valve unit 32 differs from the pilot valve unit 32 according to the first embodiment ( Fig. 1 ). The other elements are identical, so reference is made to the above description for them.

[0062] Extending from the supply port 6 is a supply pressure path 70, which is divided into a supply branch 74, a control branch 76, and a compensation path 86. The compensation path 86 pneumatically connects the supply pressure path 70 to a parking brake control pressure line 33, which provides the parking brake control pressure pPS to the main valve unit 34.

[0063] A compensation valve 80 is arranged in the compensation path 82. The compensation valve 80 is designed as a 3 / 2-way valve. The compensation valve 80 has a first compensation valve connection 80.1, which is pneumatically connected to the supply pressure path 70. The compensation valve 80 has a second compensation valve connection 80.2, which is pneumatically connected to the compensation path 82. The compensation valve 80 has a third compensation valve connection 80.3, which is pneumatically connected to a vent line 44. The vent line 44 is connected to a vent connection 3, which vents to the environment.

[0064] The compensation valve 80 has a compensation valve control port 80.4, which is pneumatically connected to the second compensation valve port 80.2 via a compensation control path 83. Pneumatic self-locking is preferably implemented by means of the compensation control path 83. A pressure present at the second compensation valve port 80.2, in particular a parking brake control pressure pPS, is provided to the compensation valve control port 80.4 via the compensation control path 83.

[0065] In a second switching position 80B of the compensation valve 80, the first compensation valve port 80.1 is pneumatically connected to the second compensation valve port 80.2, and preferably the third compensation valve port 80.3 is closed. In the second switching position 80B, the supply pressure path 70 is thus pneumatically connected to the compensation path 82 and thus to the parking brake control pressure line 33. In a first switching position 80A of the compensation valve 80, the second compensation valve port 80.2 is pneumatically connected to the third compensation valve port 80.3, and preferably the first compensation valve port 80.1 is closed. In the first switching position 80A, the compensation path 82 and thus the parking brake control pressure line 33 are pneumatically connected to the vent connection 3.

[0066] In the present case, the compensation valve 80 has a first throttle 27 between the first compensation valve connection 80.1 and the second compensation valve connection 80.2. The first throttle 27 advantageously has a nominal diameter that is smaller than the compensation path 82 and / or the supply pressure path 70. In the present case, the compensation valve 80 has a second throttle 28 between the second compensation valve connection 80.2 and the third compensation valve connection 80.3. The second throttle 28 advantageously has a nominal diameter that is smaller than the compensation path 82 and / or the vent line 44.

[0067] The pilot valve unit 32 has in the embodiment shown here ( Fig. 3 ) a first pilot valve 41 and a second pilot valve 42, each designed as a 2 / 2-way solenoid valve. By means of the first pilot valve 41, in an open position 41A, the supply pressure pV from the supply pressure path 70 can be provided as parking brake control pressure pPS to the parking brake control pressure line 33. The parking brake control pressure line 33 is arranged between the first pilot valve 41 and the second pilot valve 42 and is or can be connected pneumatically to the relay valve control connection 16.4 or the shuttle valve 60.

[0068] By switching the first pilot valve 41 to a blocking position 41B, the parking brake control pressure pPS in the parking brake control pressure line 33, in particular at the relay valve control port 16.4, can be captured or held for permanent actuation. The second pilot valve 42 is also in a blocking position 42B. According to the design of the pilot valve unit 32 with a first pilot valve 41 and a second pilot valve 42, the parking brake control unit 10 provides the first switching signal S1 to control the first pilot valve 41 and the second switching signal S2 to control the second pilot valve 42. By switching the second pilot valve 42 to an open position 42A, the parking brake control pressure line 33 can be pneumatically connected to the vent line 44 to vent the relay valve control port 16.4.

[0069] The parking brake control pressure line 33 is additionally—as already known from the first exemplary embodiment—pneumatically connectable to the anti-compound connection 62. By means of the anti-compound connection 62, an additional parking brake pressure pSZ can be provided to the parking brake control pressure line 33 and, in particular, to the relay valve control connection 16.4 in order to control a parking brake pressure pBP at the spring-loaded connection 8, 9 independently of the pilot valve unit 32. In particular, the additional parking brake pressure pSZ can be provided by a service brake function (not shown here) in order to implement an anti-compound function.

[0070] The electropneumatic parking brake device 1 has a parking brake pressure sensor 64 which is pneumatically connected to the spring-loaded connection 8, 9 for measuring the parking brake pressure pBP.

[0071] The third embodiment according to Fig. 4 is based on the second embodiment according to Fig. 3 . The only difference between the third embodiment ( Fig. 4 ) and the second embodiment ( Fig. 2 ) is that the bypass branch line 56 does not branch off from the parking brake pressure line 54, i.e., downstream of the relay valve 16, but rather between the pilot valve unit 32 and the main valve unit 34, so that the bypass valve 50 can vent or supply the parking brake control pressure pPS, depending on the switching position. This can increase air flow efficiency.

[0072] Fig. 5 now shows a second vehicle 200, which is essentially based on the embodiment of the Fig. 1 so that identical and similar elements are provided with the same reference numerals and the differences are highlighted below. In contrast to the vehicle 200 according to Fig. 2 the vehicle has 200 according to Fig. 5 an electropneumatic parking brake device 1 in which the bypass valve 50 is arranged separately and externally to the parking brake valve unit 24. The parking brake valve unit 24, together with the parking brake control unit 10, is integrated into a conventional parking brake module 25. The parking brake module 25 has a parking brake module housing 26. The bypass valve 50 can be flange-mounted to the parking brake module housing 26 or installed separately and remotely from it in the brake system 204. The bypass branch line 56 then branches off externally from the parking brake module 25, specifically from a spring-loaded brake pressure line 46a, 46b, which runs from the first spring-loaded brake connection 8 to the first and third spring-loaded brake cylinders 242a, 242c or from the second spring-loaded brake connection 9 to the second and fourth spring-loaded brake cylinders 242b, 242d.Which of the first and second spring-loaded brake pressure lines 46a, 46b the bypass branch line 56 branches off from is functionally irrelevant and should be selected to achieve the smallest possible installation space. In the embodiment shown here (. Fig. 5 ), the bypass branch line 56 branches off from the second spring brake pressure line 46b via a bypass branch node 57. Since (as in Fig. 1 Since (as shown) the first and second spring-loaded brake connections 8, 9 are connected internally in the electro-pneumatic parking brake module 2 directly and without further intermediate circuits, it is sufficient to vent or release one of the first and second spring-loaded brake pressure lines 46a, 46b in order to vent or release all four spring-loaded brake cylinders 242a - 242d.

[0073] The Fig. 6 and 7 now show embodiments that can be used in the context of the vehicle 200 according to Fig. 5 can be used and thus also include externally arranged bypass valves 50. Identical and similar elements are again provided with the same reference numerals, so that reference is made in full to the above description. The differences from the previous embodiments are particularly highlighted below.

[0074] The Fig. 6 The embodiment shown is largely based on the one in Fig. 1 The embodiment shown and in particular the pilot valve unit 32 and the main valve unit 34 are of identical design.

[0075] In accordance with the Fig. 5 In the exemplary embodiment shown, the bypass branch line 56 branches off externally from the parking brake module housing 26 and thus also downstream from the second spring-loaded brake connection 9. The bypass supply line 53 also runs externally to the parking brake module housing 26 and branches off from the bypass supply node 51, which is arranged upstream of the supply connection 6, i.e. between the parking brake supply 26 and the supply connection 6. The bypass valve 50 is therefore constructed completely parallel to the parking brake valve unit 24 and can connect the second spring-loaded brake pressure line 46b immediately and directly to the parking brake supply 26.

[0076] The Fig. 7 The embodiment shown now differs from the one in Fig. 6shown embodiment in that the second bypass valve connection 50.2 is not connected to the parking brake supply 26 via a bypass supply line 53, but to a vent 3. In this embodiment, it is therefore not possible to vent the spring-loaded connection 8, but only to vent it. LIST OF REFERENCE SYMBOLS (PART OF THE DESCRIPTION)

[0077] 1 Electropneumatic parking brake system 2 Parking brake module 3 Bleeding 4 Module housing 6 Supply connection 7 First compressed air supply 8 First spring-loaded connection 9 Second spring-loaded connection 10 Parking brake control unit 11 Second compressed air supply 12 Bistable valve 12.1 First bistable valve connection 12.2 Second bistable valve connection 12.3 Third bistable valve connection 14 Holding valve 14.1 First holding valve connection 14.2 Second holding valve connection 16 Relay valve 16.1 Relay valve supply connection 16.2 Relay valve working connection 16.3 Relay valve bleed connection 16.4 Relay valve control connection 24 Parking brake valve unit 25 Parking brake module 25a Parking brake module housing 26 Parking brake supply 27 First throttle 28 Second throttle 30 Check valve 32Pilot valve unit 33Parking brake control pressure line 34Main valve unit 40Further electronic control unit 41First pilot valve 41AOpening position of the first pilot valve 41BClosing position of the first pilot valve 42SecondPilot valve 42AOpen position of the second pilot valve 42BBlocking position of the second pilot valve 44Vent line 46aFirst spring brake pressure line 46bSecond spring brake pressure line 50Bypass valve 50.1First bypass valve connection 50.2Second bypass valve connection 50ABlocking position of the bypass valve 50BPassing position of the bypass valve 51Bypass supply node 52Bypass pressure sensor 53Bypass supply line 54Parking brake pressure line 56Bypass branch line 57Bypass branch node 60Shuttle valve 60.1First shuttle valve connection 60.2Second shuttle valve connection 62Anti-compound connection 64Parking brake pressure sensor 70Supply pressure path 74Supply branch of the supply pressure path 76Control branch of the supply pressure path 80Compensation valve 80AFirst switching position of the compensation valve 80BSwitching position of the compensation valve 80.1First compensation valve connection 80.2Second compensation valve connection 80.3Third compensation valve connection80.4 Compensation valve control connection 82 Compensation path 83 Compensation control path 200 Vehicle 202 Commercial vehicle 204 Electronically controllable pneumatic braking system 206 Vehicle bus 208 Autonomous driving unit 210 Second voltage source 212 First voltage source 220 Front axle modulator 222 Front axle supply connection 224 Front axle signal line 226 First ABS valve 227 Second ABS valve 228 a First front axle service brake actuator 228 b Second front axle service brake actuator 230 Rear axle modulator 232 a First rear axle service brake actuator 232 b Second rear axle service brake actuator 232 c Third rear axle service brake actuator 232 d Fourth Rear axle service brake actuator 242a First spring brake cylinder 242b Second spring brake cylinder 242c Third spring brake cylinder 242d Fourth spring brake cylinder 250 Trailer control unit 251 Trailer brake pressure connection 252 Trailer signal line 253 Trailer redundancy connection 254 Front axle shuttle valve256 Front axle redundancy connection 258 Rear axle redundancy connection 260 Rear axle shuttle valve 262 Foot brake pedal 264 Spring accumulator connection 266 Bypass signal line 300 First electronic control unit 302 Second electronic control unit 400 Primary control unit 402 Secondary control unit 404 First redundancy brake pressure connection 406 Second redundancy brake pressure connection A1 First axle A2 Second axle B1 Operating level B2 First redundancy level B3 Second redundancy level HA1 First rear axle HA2 Second rear axle pBFFoot brake pressure pBHA Rear axle service brake pressure pBPParking brake pressure pBVA Front axle service brake pressure pPSParking brake control pressure pR1 First redundancy brake pressure pR2 Second redundancy brake pressure pSZ Additional parking brake pressure pV Supply pressure S1 first switching signal S2 second switching signal SBBypass switching signal SBAbrake request signals SBTtrailer brake signals SBVfront axle brake signals SDBBypass pressure signal SPparking brake signal VAfront axle

Claims

1. Electropneumatic parking brake device (1) for venting and bleeding one or more spring brake cylinders of an electronically controllable pneumatic brake system (204) for a vehicle (200, 202), comprising a parking brake valve unit (24) having a supply connection for receiving supply pressure (pV) from a parking brake supply (26), the parking brake valve unit (24) modulating a parking brake pressure (pBP) at at least one spring-loaded connection (8, 9) on the basis of a parking brake signal (SP), and a non-return valve (30) arranged between the parking brake valve unit (24) and the parking brake supply (26) to prevent a backflow of compressed air from the parking brake valve unit (24) to the parking brake supply (26), characterized by a bypass valve (50) which can be switched to vent and bleed the spring-loaded connection (8, 9), the bypass valve (50) being controlled and switched independently of the parking brake valve unit (24).

2. Electropneumatic parking brake device according to claim 1, wherein the bypass valve (50) is electromagnetic and can be controlled by a further electronic control unit (40) independent of the parking brake valve unit (24).

3. Electropneumatic parking brake device according to claim 2, comprising a bypass pressure sensor (52) for detecting the parking brake pressure (pBP) modulated at the spring-loaded connection, wherein the bypass pressure sensor (52) is connected to the further electronic control unit (40) which is independent of the parking brake valve unit (24).

4. Electropneumatic parking brake device according to any of the preceding claims, wherein the bypass valve (50) is monostable and can assume a blocking position (50A) and a passing-through position (50B), wherein the bypass valve (50) is stable in the blocking position (50A).

5. Electropneumatic parking brake device according to any of the preceding claims, wherein the bypass valve (50) has a first bypass valve connection (50.1) connected to the spring-loaded connection (8, 9) or to a main valve unit (34) upstream of the spring-loaded connection (8, 9) and a second bypass valve connection (50.2) connected to a bleed means (3).

6. Electropneumatic parking brake device according to any of the preceding claims 1 to 4, wherein the bypass valve (50) has a first bypass valve connection (50.1) connected to the spring-loaded connection (8, 9) or to a main valve unit (34) upstream of the spring-loaded connection (8, 9) and a second bypass valve connection (50.2) connected to the parking brake supply (26) upstream of the non-return valve (30).

7. Electropneumatic parking brake device according to any of the preceding claims, wherein the bypass valve (50) together with the parking brake valve unit (24) is designed as a structural unit.

8. Electropneumatic parking brake device according to any of the preceding claims, wherein the bypass valve (50) is accommodated with the parking brake valve unit (24) in a module housing (4).

9. Electropneumatic parking brake device according to any of the preceding claims, wherein the bypass valve (50) is connected directly to a parking brake pressure line (54) coupled to the spring-loaded connection (8, 9) downstream thereof.

10. Electropneumatic parking brake device according to any of the preceding claims, wherein the parking brake valve unit (24) has a pilot valve unit (32) and a main valve unit (34), wherein the pilot valve unit (32) is intended to modulate a parking brake control pressure (pPS) at the main valve unit (34), which then modulates the parking brake pressure (pBP) at the spring-loaded connection (8, 9) on the basis of the received parking brake control pressure (pPS).

11. Electropneumatic parking brake device according to claim 10, wherein the first bypass valve (50) is connected to the main valve unit (34), wherein the parking brake control pressure (pPS) can be bled via the bypass valve (50).

12. Electropneumatic parking brake device according to claim 11, wherein the bypass valve (50) is connected to a bypass branch line (56) which branches off from a parking brake control pressure line (33) via which the parking brake control pressure (pPS) is provided to the main valve unit (34) by the pilot valve unit (32).

13. Electropneumatic parking brake device according to claim 12, wherein a first shuttle valve (60) is provided in the parking brake control pressure line (33), which has a first shuttle valve connection (60.1) connected to the pilot valve unit (32), a second shuttle valve connection (60.2) connected to an anti-compound connection (62) and a third shuttle valve connection (60.3) connected to the main valve unit (34), wherein the first shuttle valve (60) respectively modulates, at the third shuttle valve connection (60.3), the higher pressure present at the first shuttle valve connection (60.1) and the second shuttle valve connection (60.2).

14. Electropneumatic parking brake device according to claim 13, wherein the bypass branch line (56) branches off between the first shuttle valve connection (60.1) and the pilot valve unit (32).

15. Electropneumatic parking brake device according to any of the preceding claims 10 to 14, wherein the parking brake valve unit (24) has a compensation valve (80) which is provided to maintain a parking brake control pressure (pPS) modulated by the pilot valve unit (32) at the main valve unit (34) and thus at least partially compensate for a leakage in the pilot valve unit (32) and / or the main valve unit (34).

16. Electropneumatic parking brake device according to claim 15, wherein the compensation valve (80) is designed as a pneumatically switchable 3 / 2-way valve (81) and has a first compensation valve connection (80.1) connected to the non-return valve (30), a second compensation valve connection (80.2) connected to a line (82) guiding the parking brake control pressure (pPS) and a third compensation valve connection (80.3) connected to a bleed means (3), wherein the compensation valve (80) is spring-loaded a first switching position is preloaded, in which the second compensation valve connection (80.2) is connected to the third compensation valve connection (80.3) and if a compensation valve control pressure (pSK) provided at a compensation valve control connection (80.4) exceeds a compensation valve threshold value, switches to a second switching position in which the first compensation valve connection (80.1) is connected to the second compensation valve connection (80.2), and wherein the compensation valve control pressure (pSK) is a pressure (pPS) present or modulated at the second compensation valve connection (80.2), whereby pneumatic locking for the compensation valve (80) is implemented.

17. Electropneumatic parking brake device according to claim 16, wherein the compensation valve (80) is designed to be throttled such that the connection of the first compensation valve connection (80.1) to the second compensation valve connection (80.2) and the connection of the second compensation valve connection (80.2) to the third compensation valve connection (80.3) are each throttled.

18. Electropneumatic parking brake device according to any of the preceding claims, wherein the parking brake valve unit (24) and the bypass valve (50) are supplied with electrical voltage from two independent voltage sources (210, 212).

19. Electronically controllable pneumatic brake system (204) for a vehicle (200, 202), comprising at least one first front-axle brake actuator (228a) and one second front-axle brake actuator (228b) on a front axle (VA) of the vehicle (200) and at least one first rear-axle brake actuator (242a) and one second rear-axle brake actuator (242b) on a rear axle (HA1, HA2) of the vehicle (200); a primary system (B1) having a primary control unit (400) at least for controlling the first front-axle brake actuator (228a), the second front-axle brake actuator (228b), the first rear-axle brake actuator (242a) and the second rear-axle brake actuator (242b); and an electropneumatic parking brake device (1) according to any of claims 1 to 18, wherein at least one first spring brake cylinder (232a) is coupled to the at least one spring-loaded brake connection (8, 9) at the rear axle (HA1, HA2), and wherein the bypass valve (50) can be switched for venting and bleeding the first spring brake cylinder (242a), wherein the bypass valve (50) is controlled and switched independently of the parking brake valve unit (24).

20. Electronically controllable pneumatic brake system (1) according to claim 19, wherein the parking brake valve unit (24) is connected to a parking brake control unit (10) and receives switching signals (S1, S2) therefrom, and wherein the bypass valve (50) is connected to a further electronic control unit (40) independent of the parking brake valve unit (24) and receives at least one bypass switching signal (SB) therefrom.

21. Electronically controllable pneumatic brake system (1) according to claim 20, wherein the parking brake control unit (10) is connected to a first voltage source (212) and is supplied with electrical voltage thereby, and the further electronic control unit (40) is connected to a second voltage source (210) and is supplied with electrical voltage thereby.

22. Electronically controllable pneumatic brake system (1) according to any of the preceding claims 19 to 21, wherein the primary control unit (400) forms or comprises the further control unit (40).

23. Electronically controllable pneumatic brake system (1) according to any of the preceding claims 19 to 22, further comprising a secondary system (B2) having a secondary control unit (404) at least for controlling the first front-axle brake actuator (20a), the second front-axle brake actuator (20b), the first rear-axle brake actuator (18a) and the second rear-axle brake actuator (18b), wherein in the case that an error (F) is determined in the primary system (6), the electronically controllable pneumatic brake system (1) is controlled at least partially by the secondary system (8).

24. Electronically controllable pneumatic brake system according to claim 23, wherein the secondary control unit (40) forms or comprises the further control unit.

25. Vehicle (2), in particular commercial vehicle (200), comprising a front axle (VA), at least one first rear axle (HA1) and an electronically controllable pneumatic brake system (1) according to any of the preceding claims 19 to 24.

26. Method for controlling an electronically controllable pneumatic brake system, preferably according to any of claims 19 to 24, having the following steps: - controlling a parking brake valve unit by means of a parking brake control unit (10) for venting and bleeding at least one spring brake cylinder (19a) on a rear axle (HA1, HA2) of a commercial vehicle, wherein the parking brake valve unit is connected to a parking brake supply via a non-return valve and receives supply pressure therefrom; - determining a fault in the electronically controllable pneumatic brake system, in particular the parking brake control unit (10) or parking brake valve unit; - switching a bypass valve, which is connected both to the at least one spring brake cylinder and to the parking brake supply, into a bleeding position for bleeding the at least one spring brake cylinder; wherein the bypass valve switches in response to a bypass switching signal provided by a further electronic control unit which is independent of the parking brake control unit (10).

27. Method according to claim 26, wherein the parking brake control unit (10) is connected to a first voltage source and is supplied with electrical voltage thereby, and the further control unit is connected to a second voltage source and is supplied with electrical voltage thereby.

28. Method according to either claim 26 or claim 27, comprising the step of: - lowering the supply pressure in the parking brake supply to bleed the at least one spring brake cylinder.