Fail-safe bypass valve assembly and brake system including same

Abstract

The present invention relates to a fail-safe bypass valve assembly (1) for a pneumatic parking brake unit (120) of an electronically controllable pneumatic braking system (100), comprising: a first path (2) with an electromagnetic monostable valve (6); a second path (4) with a bistable valve unit (12); and a relay valve (10); wherein the first path (2) and the second path (4) receive a main parking brake pressure (pPA) from the pneumatic parking brake unit (120), wherein, at a first stable switching position of the bistable valve unit (12), the main parking brake pressure (pPA) is controlled at the relay valve control port (10.4) of the relay valve (10) independently of the switching position of the first monostable valve (6), and at a second stable switching position of the bistable valve unit (12), the relay valve control port (10.4) vents when the first monostable valve (6) is de-energized to vent at least one spring-loaded brake cylinder (125a, 125b).

Description

Technical Field

[0001] This invention relates to a fail-safe bypass valve assembly for a pneumatic parking brake unit in an electronically controllable pneumatic braking system for vehicles. The invention also relates to an electronically controllable pneumatic braking system and a commercial vehicle. Background Technology

[0002] For vehicles capable of automatic operation, especially those with automation levels three to five, a fail-safe system is needed to ensure the vehicle is safely parked in the event of a serious malfunction. For example, a system known from document DE 102019 133 010 A1, after vehicle startup, first releases the parking brake, i.e., inflates the spring-loaded brake cylinder, then switches it back to the parking state, i.e., deflates the spring-loaded brake cylinder, and then, either simultaneously or consecutively, inflates the spring-loaded brake cylinder through a separately provided monostable release valve, which is de-energized and enters a switching position in the event of a malfunction, thus restoring the spring-loaded brake cylinder to the deflated state. However, this means that the parking brake remains in the deflated state even while driving, and then switches to the tensioned state, which can lead to a logical error in some situations. In this case, if the parking brake status is queried through other systems, it will report that the parking brake is tensioned and therefore in the parking state, which can lead to a logical error while the vehicle is in motion.

[0003] Other systems designed to tension spring-operated brake cylinders in severe fault conditions also rely on similar functionality or directly use the parking brake to activate the spring accumulator. The problem with using the parking brake itself to tension the spring-operated brake cylinder in a fault condition lies in the bistable nature of parking brakes. To avoid continuously energizing one or more valves during driving, parking brake modules are typically designed to be bistable, meaning they maintain their switched positions without current. Therefore, if the parking brake is switched to a driving state where the spring-operated brake cylinder is inflated while the vehicle is in motion, this state persists even when the parking brake unit is de-energized. The spring-operated brake cylinder will only tension if the compressed air supply system fails and the supply pressure drops. This often results in the vehicle being unable to park and brake safely in the event of a power outage.

[0004] Other related systems have been disclosed in documents such as DE 10 2018 108 092 A1, WO 2018 / 172256 A1, WO 2018 / 172268 A1, DE 10 2019 106 591 A1, DE 20 2019 106870 U1 and DE 10 2020 131 688 A1.

[0005] However, there remains a need to ensure the vehicle's safety in case of a malfunction, starting with the parking brake in its released driving position, i.e., the inflated driving position. In particular, such systems should be retrofittable, meaning they can be connected to existing systems, and especially should not lead to reasonable errors in the vehicle. Summary of the Invention

[0006] The present invention solves the problems of the aforementioned type of fail-safe bypass valve assembly through the features of claim 1. It thereby provides a first path with at least one electromagnetic first monostable valve, a second path with a bistable valve unit, and a relay valve. According to the invention, the first and second paths are configured and constructed to be connected via a Y-shaped element to the parking brake pressure port of a pneumatic parking brake unit to receive the main parking brake pressure of the pneumatic parking brake unit. The first monostable valve and the bistable valve unit are arranged in parallel with each other and connected to the relay valve control port of the relay valve to control the main parking brake pressure received from the pneumatic parking brake unit at the relay valve control port, particularly selectively controlled via the first monostable valve and / or the bistable valve unit. The relay valve has a relay valve operating port connected to at least one spring-recharged brake cylinder of an electronically controllable pneumatic braking system to control the main parking brake pressure received at the relay valve control port to be amplified at at least one spring-recharged brake cylinder. Here, according to the present invention, in the first stable switching position of the bistable valve unit, the main parking brake pressure is controlled independently of the switching position of the first monostable valve; while in the second stable switching position of the bistable valve unit, the relay valve control port exhausts gas when the first monostable valve is de-energized, so as to exhaust gas from at least one spring-energy-storage brake cylinder.

[0007] The fail-safe bypass valve assembly proposed herein can be integrated into existing systems by connecting the first and second paths via a Y-shaped element to the parking brake port of an existing pneumatic parking brake unit. This parking brake port is typically connected to at least one spring-loaded brake cylinder, and the main parking brake pressure is directly supplied to the at least one spring-loaded brake cylinder via this parking brake port. In a preferred embodiment, the parking brake pressure port is the parking brake operating port of the parking brake unit. "Main parking brake pressure" refers to the pressure controlled by the parking brake unit, whether it is the operating pressure preferably supplied directly to one or more spring-loaded brake cylinders, or the control pressure that needs to be amplified before being supplied to one or more spring-loaded brake cylinders. In one embodiment, the parking brake pressure port of the parking brake unit is the port that provides the parking brake control pressure. In this embodiment, the main parking brake pressure is the parking brake control pressure.

[0008] The relay valve of the fail-safe bypass valve assembly according to the invention is connected via its working port to at least one spring-recharged brake cylinder, rather than to the parking brake unit, such that the fail-safe bypass valve assembly is installed between the parking brake unit and at least one spring-recharged brake cylinder, or alternatively in parallel with it. Of course, this fail-safe bypass valve assembly can be pre-installed at the factory, but as mentioned above, it can also be advantageously integrated into existing systems. It is also conceivable to integrate this fail-safe bypass valve assembly directly into the parking brake module, and it can be integrated into the housing of an existing parking brake unit. The pressure controlled by the relay valve at at least one spring-recharged brake cylinder is referred to as the "secondary parking brake pressure".

[0009] In the first stable switching position of the bistable valve unit, the main parking brake pressure is controlled independently of the switching position of the first monostable valve, preferably at the relay valve control port, so that the normal operation of the pneumatic parking brake unit is not adversely affected in the first stable switching position. A slight delay occurs due to the presence of the intermediate valve; however, the main parking brake pressure controlled by the parking brake unit is equivalent to control at at least one spring-loaded brake cylinder. Therefore, if the pneumatic parking brake unit is in the driving position, at least one spring-loaded brake cylinder is released; if the pneumatic parking brake unit is in the parking position, at least one spring-loaded brake cylinder is vented. In the second stable switching position of the bistable valve unit, the relay valve control port vents when the first monostable valve is de-energized, while when the first monostable valve is energized, the main parking brake pressure is preferably controlled at the relay valve control port. Therefore, if the first monostable valve is de-energized, the relay valve control port will vent regardless of the state of the pneumatic parking brake unit, i.e., whether the pneumatic parking brake unit is in the driving or parking position, thus causing at least one spring-loaded brake cylinder to vent and thus tension. In this way, a fail-safe function can be achieved by at least one monostable valve, which causes at least one spring-loaded brake cylinder to vent in the event of a serious fault that de-energizes at least one first monostable valve. This function can be activated by correspondingly switching the bistable valve unit to either the first stable position or the second stable position. Although the first monostable valve has no effect on the state of at least one spring-loaded brake cylinder when the bistable valve unit is in the first stable position, it can vent through the monostable valve when the bistable valve unit is in the second stable position. Therefore, it is advantageous, even necessary, for the driver to switch the bistable valve unit to the first stable position when the driver is personally controlling the vehicle, and to switch it to the second stable position when the vehicle is driving automatically.

[0010] In a preferred embodiment, an electromagnetic second monostable valve is provided in the first circuit, pneumatically connected in series with the first monostable valve. Therefore, if the first and second monostable valves are connected such that de-energizing either one allows at least one spring-loaded brake cylinder to release gas, safety is further improved. Thus, the second monostable valve is provided to prevent gas release from the relay valve control port if one of the two valves fails and de-energizing the valve. Therefore, this function is also redundant.

[0011] Furthermore, preferably, at least the first monostable valve is in the venting position when de-energized. The second monostable valve is also preferably in the venting position. The first and second monostable valves are preferably configured as monostable 3 / 2 directional valves, wherein they alternately connect the path to the relay valve control port to the path originating from the parking brake pressure port or the venting port.

[0012] In another preferred embodiment, the fail-safe bypass valve assembly includes a switching valve having a first input, a second input, and an output. This switching valve is preferably configured as a high-position selector valve, which always provides the higher of the pressures applied at the first and second inputs at the output. Preferably, the first input is directly or indirectly connected to a first path, the second input to a second path, and the output to a relay valve control port. Alternatively, a corresponding valve assembly with a pneumatically switchable valve performing the same function can also be provided.

[0013] Furthermore, it is preferable that the bistable valve unit has a manually operable 3 / 2 directional control valve. For example, such a manually operable 3 / 2 directional control valve can be configured as a spool valve. It is preferably located in the driver's cab, allowing the driver to switch between the two modes, namely manual driving mode and automatic mode.

[0014] Furthermore, it is preferable that the bistable valve unit has a pneumatic or electromechanical bistable state. For example, a pneumatic bistable state can be constructed using a pneumatically self-holding valve or a valve assembly having a total of three valves connected to achieve pneumatic bistable state. Such connection methods are known to those skilled in the art. Electromechanical bistable state can be achieved, in particular, using an electromagnetic bistable valve, which preferably has a first magnet and a second magnet to provide two magnetic positioning positions in this way. Such electromagnetic bistable valves are also known to those skilled in the art.

[0015] Furthermore, the fail-safe bypass valve assembly preferably includes at least one first pressure sensor for detecting pressure that can be supplied to the relay valve control port. In this way, a signal can be provided that detects the pressure controlled or manageable at the relay valve control port, thereby allowing the relay valve control pressure to be provided to the electronic control unit for sanity checks and / or control of the braking system. Preferably, the fail-safe bypass valve assembly includes a second pressure sensor for detecting the pressure controlled by the relay valve, thereby also detecting the pressure controlled at at least one spring-loaded brake cylinder.

[0016] Preferably, the first monostable valve and / or the second monostable valve are connected to a higher-level control unit, preferably an automated driving unit, or a control unit performing automated driving functions, and receive corresponding switching signals from there. It can be specified that a switching signal is provided to switch the first or second monostable valve as long as the automated driving unit or the corresponding control unit is operational. Only when the automated driving unit, for example, loses power due to a malfunction or ceases to actively output signals, will the first or second monostable valve return (preferably by spring loading) to its stable switching position, so that the relay valve control port can subsequently vent.

[0017] In a second aspect, the present invention addresses this problem by an electronically controllable pneumatic braking system having the features of claim 11. This electronically controllable pneumatic braking system therefore includes a parking brake unit that receives air pressure from a parking brake compressed air reservoir and is configured to receive an electric or pneumatic parking brake signal and control the main parking brake pressure at the parking brake pressure port according to the parking brake signal. The electronically controllable pneumatic braking system also includes at least one spring-energy-storing brake cylinder on at least one axle, an automatic driving unit connected at least via a vehicle bus to at least one other electronic brake controller, and a fail-safe bypass valve assembly preferably constructed according to one of the above-described preferred embodiments of the fail-safe bypass valve assembly according to the first aspect of the invention. Here, both the first and second paths of the fail-safe bypass valve assembly are connected to and receive the main parking brake pressure from the parking brake pressure port of the parking brake unit. The relay valve operating port of the bypass valve assembly is connected to at least one spring-energy-storing brake cylinder, and the first monostable valve of the fail-safe bypass valve assembly is connected to and receives a switching signal from the automatic driving unit.

[0018] It should be understood that the fail-safe bypass valve assembly according to the first aspect of the invention has the same and similar sub-aspects as the electronically controllable pneumatic braking system according to the second aspect of the invention, which are particularly set forth in the dependent claims.

[0019] Preferably, in an electronically controllable pneumatic braking system, the parking brake unit includes a parking brake switch located in the driver's cab. Furthermore, it is also preferred that the parking brake unit includes a manually operable parking brake valve.

[0020] Preferably, the first pressure sensor or the second pressure sensor of the bypass valve assembly is connected to the autonomous driving unit and provides it with a first pressure signal or a second pressure signal.

[0021] In a third aspect, the present invention solves the problems described at the beginning by means of a commercial vehicle according to claim 15, the commercial vehicle having a front axle and a rear axle, and an electronically controllable pneumatic braking system according to one of the preferred embodiments described above of the electronically controllable pneumatic braking system according to the second aspect of the present invention. It should be understood that the electronically controllable pneumatic braking system according to the second aspect of the present invention and the commercial vehicle according to the third aspect of the present invention have the same and similar sub-aspects, which are particularly set forth in the dependent claims. In this regard, please refer entirely to the above description. Attached Figure Description

[0022] Embodiments of the invention will now be described with reference to the accompanying drawings. These drawings are not necessarily drawn to scale; rather, they are presented schematically and / or slightly modified where illustrative purposes are helpful. For supplementation to the teachings directly visible in the drawings, please refer to the relevant prior art. It should be noted that various modifications and changes to the form and details of the embodiments can be made without departing from the overall spirit of the invention. The features of the invention disclosed in the specification, drawings, and claims, whether used individually or in any combination, are essential for the further development of the invention. Furthermore, all combinations of at least two features disclosed in the specification, drawings, and / or claims fall within the scope of the invention. The overall spirit of the invention is not limited to the specific form or details of the preferred embodiments shown and described below, nor is it limited to the object restricted compared to the object claimed in the claims. Values ​​within the specified design range should also be disclosed as boundary values ​​and can be used and claimed arbitrarily. For simplicity, the same reference numerals are used below for the same or similar components, or components having the same or similar functions.

[0023] Other advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and with reference to the accompanying drawings; wherein:

[0024] Figure 1 An electronically controllable pneumatic braking system is shown, which has a fail-safe bypass valve assembly as shown in the first embodiment;

[0025] Figure 2 It shows according to Figure 1 An electronically controllable pneumatic braking system having a fail-safe bypass valve assembly as shown in the second embodiment;

[0026] Figure 3 Another electronically controllable pneumatic braking system is shown, which has according to Figure 1 The bypass valve assembly; and

[0027] Figure 4 It shows according to Figure 1An electronically controllable pneumatic braking system having a fail-safe bypass valve assembly as described in the third embodiment. Detailed Implementation

[0028] The figures first describe the common elements, and then illustrate the differences between the various embodiments. The commonalities are not emphasized here, and it should be understood that, in principle, each embodiment can be combined with other embodiments.

[0029] Figure 1 An electronically controllable pneumatic braking system 100 for a vehicle 200, particularly a commercial vehicle 202, is shown. The vehicle 200 has a front axle VA and a rear axle HA, wherein the invention also includes vehicles 200 having more than one (particularly two, three, or more) rear axles and more than one (particularly two, three, or four) front axles. The electronically controllable pneumatic braking system 100 has a rear axle modulator 102 on the rear axle HA, which receives a storage air pressure pV from a first compressed air reservoir 103 and controls the rear axle braking pressure pBHA at the first and second rear axle brake actuators 104a and 104b in a known manner according to a braking request signal. A front axle modulator 106 is similarly provided on the front axle VA, which receives a storage air pressure pV from a second compressed air reservoir 107 and controls the front axle braking pressure pBVA at the first and second front axle brake actuators 108a and 108b in a known manner. A first ABS valve 109a and a second ABS valve 109b are additionally provided at the front axle VA to achieve the anti-lock braking function.

[0030] Both the rear axle modulator 102 and the front axle modulator 106 are connected to a central module 110, which provides braking signals to the rear axle modulator 102 and the front axle modulator 106 in a known manner. These braking signals are then processed by the rear axle modulator 102 and the front axle modulator 106 and provided to solenoid valves to control the rear axle braking pressure pBHA and the front axle braking pressure pBVA in this way. Alternatively, the central module 110 may be configured to connect directly to the solenoid valves of the rear axle modulator 102 and / or the front axle modulator 106, thus eliminating the need for a separate intelligent control.

[0031] This example uses an electronically controllable pneumatic braking system 100, which can be operated manually or automatically by the driver. For this purpose, the vehicle 200 first has a brake value sensor 112 in the form of a brake pedal. This brake value sensor is connected to the central module 110 and provides brake value sensor signals to it, and is also directly connected to the front axle modulator 106 and the rear axle modulator 102. This is not mandatory; it can be specified that the brake value sensor 112 is only connected to the central module 110, only pneumatically and / or electrically connected to the front axle modulator 106 and the rear axle modulator 102, or only pneumatically connected to the central module 110 and the front axle modulator 106, as exemplarily. The configuration shown here is merely exemplary, and the invention is explicitly not limited thereto.

[0032] The electronically controllable pneumatic braking system 100 also includes a parking brake circuit 115 and a parking brake unit 120 on the rear axle HA. The parking brake unit 120 is here configured as a parking brake module 121 and is thus integrated into a single structural unit. However, it is also possible that the parking brake unit 120 is not configured as a parking brake module 121, but rather implemented via a valve separately installed in the vehicle 200. The parking brake unit 120 operates as is well known in the prior art, and... Figure 1 The central structure is an electro-pneumatic parking brake unit. It is connected to the parking brake compressed air reservoir 122 (also known as the third compressed air reservoir) and receives the air pressure pV from this reservoir. Figure 1 In the illustrated embodiment, the parking brake unit 120 is connected to the automatic driving unit 113 via the vehicle bus 114, thereby receiving signals from the automatic driving unit 113 to stop or park the vehicle 200; it is also connected to the parking brake switch 124, which is typically located in the driver's cab and can be manually operated by the driver. The parking position of the vehicle 200 can also be requested via the parking brake switch 124. For this purpose, the vehicle 200 has a first spring-retaining brake cylinder 125a and a second spring-retaining brake cylinder 125b on the rear axle HA, which are known to open by inflation and tension by deflation. The parking brake unit 120 provides a main parking brake pressure pPA to inflate the spring-retaining brake cylinders 125a and 125b, which can be the parking brake operating pressure.

[0033] According to the present invention, the main parking brake pressure pPA is not directly supplied to the first spring-loaded brake cylinder 125a and the second spring-loaded brake cylinder 125b on the rear axle HA, but a fail-safe bypass valve assembly 1 is connected between the parking brake unit 120 and the spring-loaded brake cylinders 125a and 125b. Figure 1In the first embodiment shown, the fail-safe bypass valve assembly includes a first path 2 and a second path 4, both of which receive the main parking brake pressure pPA, and in the embodiment shown here, they are connected to the parking brake pressure port 126 via a Y-shaped member 5. Crucially, the first path 2 and the second path 4 receive the same main parking brake pressure pPA.

[0034] The first path 2 has an electromagnetically operated first monostable valve 6 and a series-connected electromagnetic second monostable valve 8. Both the first monostable valve 6 and the second monostable valve 8 are in the venting position when de-energized, in which the first path 2 is connected to the vent port 3. When energized, both the first monostable valve 6 and the second monostable valve 8 are in the venting position, in which the main parking brake pressure pPA can be controlled. For this purpose, both the first monostable valve 6 and the second monostable valve 8 are configured as 3 / 2 directional valves, wherein the valves are arranged such that the downstream ports of the 3 / 2 directional valves, as viewed from the parking brake unit 120, can alternately connect to the vent port 3 and the port facing the parking brake unit 120.

[0035] Downstream, the first path 2 is connected to a relay valve 10, which has a relay valve storage port 10.1 (this relay valve storage port is connected to the third compressed air storage tank 122 and receives the storage pressure pV) and a relay valve operating port 10.2. Figure 2 The diagram shows two relay valve working ports, but this is only schematic; one or both working ports can be provided. There is a relay valve exhaust port 10.3 and a relay valve control port 10.4. The relay valve working port 10.2 is connected to the first spring-loaded brake cylinder 125a and the second spring-loaded brake cylinder 125b, and the relay valve control port 10.4 is connected to either the first path 2 or the second path 4, allowing it to receive the main parking brake pressure pPA controlled by either the first path 2 or the second path 4. Figure 1 In the specific embodiment shown, the relay valve control port 10.4 is first connected to the switching valve 11, which is preferably configured as a high-position selection valve. The switching valve 11 has a first input terminal 11.1 connected to the first path 2, a second input terminal 11.2 connected to the second path 4, and an output terminal 11.3 connected to the relay valve 10, preferably to the relay valve control port 10.4. The switching valve 11 always transmits the higher of the pressure applied at the first input terminal 11.1 and the second input terminal 11.2 to the output terminal 11.3.

[0036] The first monostable valve 6 and the second monostable valve 8 are electrically connected to the autonomous driving unit 113 and receive a first switching signal S1 and a second switching signal S2 from the autonomous driving unit. During normal operation, the first switching signal S1 and the second switching signal S2 should be provided to energize, i.e., allow the first monostable valve 6 and the second monostable valve 8 to the open position. In this position, the main parking brake pressure pPA is controlled at the relay valve 10 via the first path 2, the first monostable valve 6 and the second monostable valve 8, and the switching valve 11. The relay valve then amplifies the main parking brake pressure and provides it as the secondary parking brake pressure pPR to the first spring-loaded brake cylinder 125a and the second spring-loaded brake cylinder 125b, thereby releasing them. If a serious malfunction occurs in the vehicle 200, the first switching signal S1 and / or the second switching signal S2 also fail, causing the first path 2 to vent, as at least one of the first monostable valve 6 and the second monostable valve 8 enters the venting position, thus connecting the relay valve control port 10.4 to the vent port 3. In this situation, the first spring-retaining brake cylinder 125a and the second spring-retaining brake cylinder 125b also exhaust air and thus become tensioned. This ensures a fail-safe function that allows the vehicle 200 to brake and stop safely.

[0037] For manual operation of vehicle 200, bypassing or disabling the fail-safe function may be advantageous. This fail-safe function is implemented via a first monostable valve 6 and a second monostable valve 8. To this end, a bistable valve unit 12 is provided in the second path 4. This bistable valve unit has at least one first stable switching position and one second stable switching position, wherein, in such a position… Figure 1 In the first stable switching position shown, the main parking brake pressure pPA is supplied to the switching valve 11 via the second path 4, more precisely, to the second input terminal 11.2 of the switching valve. Figure 1 The second stable switching position is not shown in the figure. The second input terminal 11.2 of the switching valve is connected to the exhaust port 3.

[0038] Therefore, if the first monostable valve 6 and the second monostable valve 8 are energized and in the open position, the switching position of the bistable valve unit 12 has no effect on the pressure controlled by the relay valve 10. However, if the bistable valve unit 12 is in the open position... Figure 1 As shown in the first stable switching position (flow position), the switching position of the first monostable valve 6 and the second monostable valve 8 has no effect on the pressure controlled by the relay valve 10, because the main parking brake pressure pPA is controlled at the switching valve 11 via the bistable valve unit 12, and is therefore also supplied to the relay valve control port 10.4. Only when the bistable valve unit 12 switches to... Figure 1Only when the second stable switching position (exhaust position) is not shown can the fail-safe function be achieved through the first monostable valve 6 and the second monostable valve 8.

[0039] exist Figure 1 In the illustrated embodiment, the bistable valve unit 12 includes a manually operable 3 / 2 directional control valve 13, which in... Figure 1 The valve is shown in the flow position and can be switched to the closed or vent position via the operating handle 13.4. The manually operable 3 / 2 directional control valve 13 has a first manual valve port 13.1, which connects to the second path 4, more specifically to the portion facing the Y-shaped member 5, and thus receives the main parking brake pressure pPA controlled by the parking brake unit 120. The manually operable 3 / 2 directional control valve 13 also has a second manual valve port 13.2, which connects downstream of the second path 4 and leads to the relay valve 10, wherein... Figure 1 In the illustrated embodiment, more precisely, it is connected to the second input terminal 11.2 of the switching valve. Furthermore, the manually operable 3 / 2 directional control valve 13 has a third manual valve port 13.3, which is connected to the exhaust port 3. In the flow position, the first manual valve port 13.1 is connected to the second manual valve port 13.2, while in the exhaust position, the second manual valve port 13.2 is connected to the third manual valve port 13.3. The manually operable 3 / 2 directional control valve 13 is preferably located in the driver's cab of the vehicle 200, but can also be arranged in other locations within the vehicle.

[0040] Advantageously, the driver can place the manually operable 3 / 2 directional control valve 13 in the position... Figure 1 The flow position shown ensures that the main parking brake pressure pPA, controlled by the parking brake unit 120, is always controlled at the relay valve control port 10.4 via the second path 4, regardless of the positions of the first monostable valve 6 and the second monostable valve 8. Therefore, the first spring-loaded brake cylinder 125a and the second spring-loaded brake cylinder 125b are charged exactly as instructed by the parking brake unit 120. As long as the main parking brake pressure pPA controlled by the parking brake unit 120 remains constant, the positions of the first spring-loaded brake cylinder 125a and the second spring-loaded brake cylinder 125b will not change even if the automatic driving unit 113 malfunctions. Therefore, the vehicle 200 behaves the same as a normally manually operated vehicle. The driver should activate this switching position when driving the vehicle 200. However, if the vehicle 200 is operating in automatic or semi-automatic mode, it is advantageous to place the manually operated 3 / 2 directional valve 13 in the position... Figure 1The second switching position (not shown) connects the second manual valve port 13.2 to the third manual valve port 13.3, thereby connecting the second input terminal 11.2 of the switching valve to the exhaust port 3. In this switching position, pressure is not transmitted through the second path 4, so the pressure at the relay valve control port 10.4 is always the pressure controlled by the first path 2. If the first monostable valve 6 and the second monostable valve 8 are energized, especially because the automatic driving unit 113 is working properly and provides the first switching signal S1 and the second switching signal S2, the spring-loaded brake cylinders 125a and 125b will recharge as instructed by the parking brake unit 120. However, if a serious malfunction occurs that causes the first switching signal S1 and / or the second switching signal S2 to no longer be provided, the first input terminal 11.1 of the switching valve will also exhaust, causing the relay valve control port 10.4 to also exhaust, which in turn causes the first spring-loaded brake cylinders 125a and 125b to exhaust, causing the vehicle to stop and lock.

[0041] Figure 2 A second embodiment of the fail-safe bypass valve assembly 1 is shown, wherein the same and similar elements are indicated by the same reference numerals so that the above description is fully applicable. (Compared to the first embodiment) Figure 1 The main difference is that in the second embodiment, the bistable valve unit 12 uses an electromagnetic bistable valve 14 instead of the manually operable 3 / 2 directional valve 13. The connection method of the electromagnetic bistable valve 14 is the same as that of the aforementioned manually operable 3 / 2 directional valve 13. The bistable valve 14 has a first bistable valve port 14.1, which is connected to the second path 4, such that the first bistable valve port constantly receives the main parking brake pressure pPA controlled by the parking brake unit 120. The second bistable valve port 14.2 is connected to the relay valve 10, more specifically to the second input terminal 11.2 of the switching valve, and the third bistable valve port 14.3 is connected to the exhaust port 3. The bistable valve 14 is known to have two magnetic positioning positions, which are exemplarily achieved here by a first magnet 15.1 and a second magnet 15.2, which are controlled by a third switching signal S3 and a fourth switching signal S4, respectively. Like the first monostable valve 6 and the second monostable valve 8, the bistable valve 14 is connected to the autonomous driving unit 113, but it can also be connected to another control unit, especially the control unit that performs the autonomous driving task. Figure 2 The illustrated embodiment is particularly advantageous in that, for example, an electrical or electronic switch for turning the automated driving operation on and off is provided in the driver's cab of the vehicle 200. For example, in the embodiment shown here, it may be specified that the automated driving unit switches the bistable valve 14 to [the specified position] when requesting automated operation. Figure 2 The exhaust position is not shown, so that the fail-safe function can be activated via the first monostable valve 6 and the second monostable valve 8.

[0042] Figure 3 The illustrated embodiments and Figure 1 The illustrated embodiment differs only in the electronically controllable pneumatic braking system 100; instead of an electro-pneumatic parking brake unit 120, a purely pneumatic parking brake valve 128 is used, which can be manually positioned in the engaged and disengaged positions. In this configuration, the parking brake valve 128 controls the main parking brake pressure pPA, which is then controlled in the first path 2 and the second path 4 as described above. All other components are constructed similarly to... Figure 1 Similarly, see the description above for details.

[0043] Figure 4 The illustrated embodiments are based on Figure 1 The embodiments shown here primarily address two differences.

[0044] First, a first pressure sensor 16 and a second pressure sensor 17 are provided, which specifically provide a first pressure signal S5 and a second pressure signal S6 to the autonomous driving unit 113. The first pressure signal S5 and the second pressure signal S6 can also be provided to other electronic control units. The first pressure sensor 16 measures the auxiliary parking brake pressure pPR controlled by the relay valve 10, while the second pressure sensor 17, in the embodiment shown here, measures the pressure controlled by the manually operable 3 / 2 directional valve 13, thereby detecting the switching position of the manually operable 3 / 2 directional valve. Therefore, the second pressure sensor 17 is typically used to detect the state of the bistable valve unit 12. The first pressure sensor 16 detects the state of the spring-loaded brake cylinder. Preferably, a third pressure sensor (not shown here) can detect the pressure controlled at the parking brake pressure port 126 to detect the state of the parking brake unit. It should be understood here that, according to... Figures 1 to 3 In the foregoing embodiments, a first pressure sensor 16 and / or a second pressure sensor 17 may also be provided.

[0045] In addition, according to Figure 4 The variant shown omits the switching valve 11. Instead, the bistable valve unit 12 and the first monostable valve 6 and the second monostable valve 8 are connected in a different manner to still achieve fail-safe functionality. Specifically, the second manual valve port 13.2 is not directly connected to the relay valve 10, but rather to the second monostable valve 8, more precisely to the second monostable valve 8 in the first embodiment ( Figure 1 The port connected to exhaust port 3 is connected in the ). Therefore, in Figure 4In the variant shown, the first monostable valve 8 can connect either the first path 2 or the second path 4 to the relay valve 10. The first monostable valve port 8.1 is connected to the first monostable valve 6 and can receive the main parking brake pressure pPA therefrom. The second monostable valve port 8.2 is connected to the relay valve 10, more precisely to the relay valve control port 10.4, while... Figure 1 The third monostable valve port 8.3, which is connected to exhaust port 3, is in Figure 4 It is connected to the second manual valve port 13.2. When power is off, the second monostable valve 8 is in the [position missing]. Figure 4 The switching position is shown, and the second manual valve port 13.2 is connected to the second monostable valve port 8.2. When energized, the second monostable valve 8 is in the [position not specified]. Figure 4 The switching position is not shown in the diagram, and the first monostable valve port 8.1 is connected to the second monostable valve port 8.2. List of reference numerals in the attached diagram: 1. Fail-safe bypass valve assembly 2 First Path 3. Exhaust port 4 Second Path 5 Y-shaped parts 6 First Monostable Valve 8. Second Monostable Valve 8.1 First Monostable Valve Port 8.2 Second Monostable Valve Port 8.3 Third Monostable Valve Port 10 Relay valve 10.1 Relay valve gas storage port 10.2 Relay valve operating port 10.3 Relay valve exhaust port 10.4 Relay Valve Control Port 11 Switching valve 11.1 First input terminal of the switching valve 11.2 Second input terminal of the switching valve 11.3 Switching valve output terminal 12 Bistable Valve Units 13 Manually operable 3 / 2 directional control valve 13.1 First manual valve port 13.2 Second manual valve port 13.3 Third manual valve port 13.4 Handle 14 Electromagnetic bistable valve 14.1 First bistable valve port 14.2 Second Bistable Valve Port 14.3 Third Bistable Valve Port 15.1 First Magnet 15.2 Second Magnet 16 First pressure sensor 17 Second pressure sensor 100 Electronically controllable pneumatic braking system 102 Rear Axle Modulator 103 First Compressed Air Storage Tank 104a, 104b Rear Axle Brake Actuators 106 Front Axle Modulator 107 Second Compressed Air Storage Tank 108a, 108b Front axle brake actuators 109a, 109b ABS valves 110 Central Module 112 Braking value sensor 113 Automated Driving Unit 114 Vehicle Bus 115 Parking brake circuit 120 Parking Brake Unit 121 Parking Brake Module 122 Third Compressed Air Tank / Parking Brake Compressed Air Tank 124 Parking brake switch 125a and 125b spring-operated brake cylinders 126 Parking brake pressure port 128 Parking brake valve 200 vehicles 202 Commercial Vehicles HA rear axle pBHA Rear Axle Braking Pressure pBVA Front Axle Braking Pressure pPA Main parking brake pressure pPR auxiliary parking brake pressure pV storage pressure S1 First switching signal S2 Second Switching Signal S3 Third Switching Signal S4 Fourth Switching Signal S5 First Pressure Signal S6 Second Pressure Signal VA front axle.

Claims

1. A fail-safe bypass valve assembly (1) for a pneumatic parking brake unit (120) of an electronically controllable pneumatic braking system (100) of a vehicle (200), wherein, The fail-safe bypass valve assembly (1) includes: - First path (2), the first path having at least one electromagnetic first monostable valve (6); - Second path (4), the second path having a bistable valve unit (12); and - Relay valve (10). The first path (2) and the second path (4) are connected to the parking brake pressure port (126) of the pneumatic parking brake unit (120) via a Y-shaped member (5) to receive the main parking brake pressure (pPA) of the pneumatic parking brake unit (120). The first monostable valve (6) and the bistable valve unit (12) are arranged in parallel and connected to the relay valve control port (10.4) of the relay valve (10) to control the main parking brake pressure (pPA) received from the pneumatic parking brake unit (120) at the relay valve control port (10.4). The relay valve (10) has a relay valve working port (10.2), which is connected to at least one spring-loaded brake cylinder (125a, 125b) of the electronically controllable pneumatic braking system (100) to control the main parking brake pressure (pPA) received at the relay valve control port (10.4) to be amplified at at least one spring-loaded brake cylinder (125a, 125b). In the first stable switching position of the bistable valve unit (12), the main parking brake pressure (pPA) is controlled at the relay valve control port (10.4) independently of the switching position of the first monostable valve (6); while in the second stable switching position of the bistable valve unit (12), the relay valve control port (10.4) exhausts gas when the first monostable valve (6) is de-energized, so as to exhaust gas from the at least one spring-energy-storage brake cylinder (125a, 125b).

2. The fail-safe bypass valve assembly (1) according to claim 1, wherein the fail-safe bypass valve assembly includes an electromagnetic second monostable valve (8) located in the first path (2), the second monostable valve being pneumatically connected in series with the first monostable valve (6).

3. The fail-safe bypass valve assembly (1) according to claim 1 or 2, wherein, At least the first monostable valve (6) is in the venting position when the power is off.

4. The fail-safe bypass valve assembly (1) according to any one of the preceding claims, the fail-safe bypass valve assembly comprising a switching valve (11) having a first input terminal (11.1), a second input terminal (11.2), and an output terminal (11.3). in, The first input terminal (11.1) of the switching valve is connected to the first path (2), the second input terminal (11.2) of the switching valve is connected to the second path (4), and the output terminal (11.3) of the switching valve is connected to the control port (10.4) of the relay valve, such that the higher of the pressure applied at the first input terminal (11.1) and the second input terminal (11.2) of the switching valve is provided to the output terminal (11.3).

5. The fail-safe bypass valve assembly (1) according to any one of the preceding claims, wherein, The bistable valve unit (12) has a manually operable 3 / 2 directional valve (13).

6. The fail-safe bypass valve assembly (1) according to any one of the preceding claims, wherein, The bistable valve unit (12) has a pneumatic or electromechanical bistable state.

7. The fail-safe bypass valve assembly (1) according to any one of the preceding claims, wherein, The bistable valve unit (12) has an electromagnetic bistable valve (14) with a first magnet (15.1) and a second magnet (15.2).

8. The fail-safe bypass valve assembly (1) according to any one of the preceding claims, the fail-safe bypass valve assembly comprising at least one first pressure sensor (16) for detecting pressure that can be supplied to the relay valve control port (10.4).

9. The fail-safe bypass valve assembly (1) according to claim 2, wherein, The second monostable valve (8) is a second 3 / 2 directional valve, and alternately connects the first monostable valve (6) and the bistable valve unit (12) to the relay valve (10).

10. The fail-safe bypass valve assembly (1) according to any one of the preceding claims, wherein, The first monostable valve (6) is connected to the autonomous driving unit (113) or control unit that performs the autonomous driving function, and receives the first switching signal (S1) therefrom.

11. An electronically controllable pneumatic braking system (100), the pneumatic braking system comprising: - Parking brake unit (120), which receives air pressure (pV) from parking brake compressed air tank (122) and is configured to receive an electric or pneumatic parking brake signal and control the main parking brake pressure (pPA) at the parking brake pressure port (126) according to the parking brake signal. - At least one spring-storage brake cylinder (125a, 125b), said spring-storage brake cylinder being located on at least one axle (HA); - An autonomous driving unit (113), which is connected to at least one additional electronic brake controller (110) via at least one vehicle bus (114); and - Fail-safe bypass valve assembly (1) according to any one of claims 1 to 10. The first path (2) and the second path (4) are both connected to the parking brake pressure port (126) of the parking brake unit (120) and receive the main parking brake pressure (pPA) therefrom. The relay valve working port (10.2) is connected to at least one spring-energy-storing brake cylinder (125a, 125b), and The first monostable valve (6) is connected to the autonomous driving unit (113) and receives a switching signal (S1) therefrom.

12. The electronically controllable pneumatic braking system (100) according to claim 11, wherein, The parking brake unit (120) has a parking brake switch (124) located in the driver's cab.

13. The electronically controllable pneumatic braking system (100) according to claim 11, wherein, The parking brake unit (120) has a manually operable parking brake valve (126).

14. The electronically controllable pneumatic braking system (100) according to any one of claims 8 and 11 to 13, wherein, The first pressure sensor (16) is connected to the autonomous driving unit (113) and provides it with a first pressure signal (S5).

15. A commercial vehicle (202) comprising a front axle (VA) and a rear axle (HA), and an electronically controllable pneumatic braking system (100) according to any one of claims 11 to 14.

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