Electro-pneumatic brake device with automatic ventilation of the spring brake

Abstract

The invention relates to an electro-pneumatic brake device (1), comprising: an electro-pneumatic parking brake circuit with spring brake cylinders (33) and a parking brake controller (30) with a pneumatic control connection (40); at least one operating brake circuit that comprises operating brake cylinders (91a, 91b), which consume compressed air, and at least one compressed air supply (8, 10) under a supply pressure, said compressed air supply providing the compressed air for the operating brake cylinders (91a, 91b); an electro-pneumatic first valve device (90a, 90b) which is controlled by an electronic controller (100) by means of a signal (S) and which is designed to remove compressed air from the at least one compressed air supply (8, 10) and supply same to the operating brake cylinders (91a, 91b) on the basis of the signal (S) of the electronic controller (100); and a pneumatically controllable second valve device (58) which is designed to connect the pneumatic control connection (40) of the parking brake controller (30) to a pressure sink (68) in at least one first switch position, wherein the pneumatically controllable second valve device (58) is directly or indirectly controlled by the supply pressure in the at least one compressed air supply (8, 10) such that the second valve device assumes the first switch position when the supply pressure falls below a supply pressure threshold. According to the invention, the electronic controller (100) is designed to generate the signal (S) regardless of an action of a driver of the motor vehicle.

Description

[0001] DESCRIPTION

[0002] Electro-pneumatic braking system with automatic venting of the spring brake

[0003] The invention relates to an electro-pneumatic braking device of a motor vehicle, according to the preamble of claim 1, and to a motor vehicle with such an electro-pneumatic braking device according to claim 16.

[0004] With such electro-pneumatic braking systems, for example, a failure of the electrical power supply to the parking brake circuit poses a problem because the electromagnetic parking brake valve unit can then no longer be actuated. In addition, the electronic parking brake control and electrical parking brake actuation device (parking brake signal transmitter) also fail. It has therefore been proposed to automatically vent the spring brake cylinders of the parking brake circuit if the electrical power supply to the parking brake circuit fails. However, such emergency braking is problematic while the vehicle is in motion because the vehicle could then come to a stop in an unsuitable location and also because such emergency braking involves rapid venting of the spring brake under high braking force, which poses the risk of a rear-end collision with following vehicles.

[0005] In the generic document EP 3 145 769 B1, it was recognized that in the event of a failure of the compressor (e.g. due to a faulty electrical power supply or due to a failure of the drive engine), which supplies the parking brake circuit and compressed air reservoirs of the service brake circuits with compressed air, a (multiple) activation of the service brake circuits by actuating a foot brake module by the driver leads to a reduction in the supply pressure in the compressed air reservoirs, which is used to pneumatically actuate the pneumatically controllable valve device to switch it to its venting position, in which the pneumatic control connection of the parking brake control device is vented, which then results in the automatic application of the spring-loaded brake cylinders. This allows the motor vehicle to be transferred to a safe parked state.

[0006] The invention is based on the object of developing an electropneumatic braking system as described above in such a way that the safe parked state can be achieved more flexibly. Furthermore, a motor vehicle with such an electropneumatic braking system is to be provided.

[0007] This object is achieved according to the invention by the features of claims 1 and 16.

[0008] Disclosure of the invention

[0009] The invention relates to an electro-pneumatic braking device of a motor vehicle, which comprises at least the following: a) An electro-pneumatic parking brake circuit with

[0010] Spring brake cylinders and a parking brake control device with a pneumatic control connection, wherein the parking brake control device is designed and configured to release the spring brake cylinders when the pneumatic control connection is vented and to apply them when the pneumatic control connection is vented, b) at least one service brake circuit comprising service brake cylinders consuming compressed air and at least one compressed air reservoir under reservoir pressure, which provides the compressed air for the service brake cylinders, c) an electro-pneumatic first valve device controlled by an electronic control system by a signal S, which is designed and configured to withdraw compressed air from the at least one compressed air reservoir depending on the signal S of the electronic control system and to supply it to the service brake cylinders, a pressure sink and / or a compressed air consumer,d) a pneumatically controllable second valve device, which is designed and configured to connect the pneumatic control connection of the parking brake control device to a pressure sink in at least one first switching position, wherein e) the pneumatically controllable second valve device is controlled directly or indirectly by the supply pressure prevailing in the at least one compressed air supply such that it assumes the at least one first switching position when the supply pressure falls below a supply pressure limit value.

[0011] The electro-pneumatic first valve device is therefore designed and configured to draw compressed air from the at least one compressed air supply, depending on the signal S from the electronic control, and to supply it to the service brake cylinders and / or a pressure sink and / or a (any other) compressed air consumer. The only decisive factor is that the service brake cylinder, the pressure sink, or the compressed air consumer draws compressed air from the at least one compressed air supply and thereby reduces the supply pressure prevailing there, in particular below the supply pressure limit.

[0012] Therefore, if the supply pressure falls below the supply pressure limit, the pneumatically controllable second valve device is switched or controlled by the then (low) supply pressure from any switching position, in particular from a second switching position, to the first switching position, in which it connects the pneumatic control port of the parking brake control device to the pressure sink. The low control pressure at the pneumatic control port of the parking brake control device then ensures that the spring-loaded brake cylinders are vented and applied. In particular, the supply pressure limit can be a predetermined supply pressure limit.

[0013] The reservoir pressure may fall below the reservoir pressure limit value, in particular, if the electronic control unit outputs signal S to the electro-pneumatic valve device in order to draw compressed air from the at least one compressed air reservoir, and if, for example, the compressor has failed. This is because the compressor cannot then supply additional compressed air to the at least one compressed air reservoir, so that by drawing compressed air (in particular repeatedly) from the at least one compressed air reservoir during at least one service braking operation, the at least one compressed air reservoir of the at least one service brake circuit is emptied, resulting in the above-described automatic application of the spring brake cylinders in order to transfer the vehicle into a safely parked state.

[0014] The braking device according to the invention can, but need not, optionally comprise within the at least one service brake circuit a service brake actuation device such as a foot brake module or a foot brake valve that generates a brake request signal caused by an actuation by the driver and feeds it into an electronic service brake control, which, depending on the service brake request signal, controls the electro-pneumatic first valve device in order to withdraw compressed air from the at least one compressed air supply and supply it to the service brake cylinders.

[0015] The invention is based on the electropneumatic braking device known from EP 3 145 769 B1 in that f) the electronic control is designed and configured to automatically generate the signal S independently of an actuation of the at least one service brake circuit by a driver of the motor vehicle, in particular independently of an actuation of the optionally provided service brake actuation device by the driver.

[0016] The invention is based, on the one hand, on the idea that, particularly in a motor vehicle with at least one at least partially autonomously controlled service brake circuit, this circuit is no longer (solely) actuated by a driver, but rather (also) by, for example, an autopilot device. This then results in the at least one compressed air reservoir being emptied during an at least partially autonomously initiated service braking operation and, for example, if the supply of compressed air to the at least one compressed air reservoir is prevented for various reasons, which then leads to automatic application of the spring-loaded brake cylinders. In this case, the signal S represents, for example, an at least partially autonomously generated brake request signal.The invention thus also solves the problem arising in EP 3 145 769 B1, according to which the emptying of at least one compressed air reservoir must be carried out by an active brake actuation by the driver, but driver intervention cannot be expected in the case of autonomously controlled service brake circuits.

[0017] Secondly, the invention is based on the idea that the signal S, which ultimately leads to the extraction of compressed air from the at least one compressed air supply, is generated by the electronic control system independently of any action by the driver of the motor vehicle, thus providing greater flexibility. This is because the generation of the signal S can be initiated by the electronic control system for any reason that is not, for example, attributable to an actuation of the service brake by the driver. Therefore, the generation of the signal S is no longer (only) tied to an actuation of the service brake by the driver, as is the case in EP 3 145 769 B1. Rather, the electronic control system can generate the signal S for any reason, in particular if it detects any error or failure of the parking brake circuit and / or the at least one service brake circuit.

[0018] The measures listed in the subclaims enable advantageous further developments and improvements of the invention specified in claim 1.

[0019] Preferably, the electronic control comprises a) an electronic service brake control unit, and / or b) a redundant electronic service brake control unit, and / or c) an electronic autopilot control unit.

[0020] In particular, the electronic service brake control unit can control or regulate the at least one service brake circuit. The redundant (secondary) electronic service brake control unit can be provided to control or regulate the at least one service brake circuit if the (primary) electronic service brake control unit has a fault or has failed.

[0021] The electronic autopilot control can also control or regulate the motor vehicle at least partially autonomously and, in particular, autonomously generate a service brake request signal, particularly depending on the driving and environmental parameters of the motor vehicle. The electronic autopilot control can also feed the autonomously generated service brake request signal into the (primary) electronic service brake control unit and / or into the redundant (secondary) electronic service brake control unit for implementation during service braking.

[0022] Furthermore, the electronic control can generate the signal S, in particular automatically, depending on a sensor signal FS supplied by a sensor device.According to one embodiment, the sensor signal FS supplied by the sensor device can comprise an error signal that indicates or represents at least one of the following failures or errors or irregular states: a) a failure or error or irregular state of the parking brake circuit and / or of the at least one service brake circuit, and / or b) a failure or error or irregular state of a power supply of the parking brake circuit and / or of the at least one service brake circuit, and / or c) a failure or error or irregular state of a drive device of the motor vehicle that drives a compressor that supplies the at least one compressed air supply with compressed air, and / or d) a failure or error or irregular state of the compressor, and / or e) no value or no plausible value for the supply pressure in the at least one compressed air supply.

[0023] The above list is not exhaustive. Therefore, the sensor device can be arranged, configured, and designed to detect any failures, errors, or irregular states of at least one component of the braking device other than the electronic control and the sensor device. The sensor device can therefore be configured and designed to detect or recognize the failure, error, or irregular state of the at least one component other than the electronic control and the sensor device and to generate an error signal corresponding to the failure, error, or irregular state as a sensor signal FS, which the electronic control then evaluates to generate the signal S as needed.

[0024] According to a further embodiment, the sensor signal FS supplied by the sensor device can comprise a signal generated as a function of driving and / or environmental parameters of the motor vehicle. The sensor device can then comprise, for example, ultrasonic and / or radar and / or camera sensors. Such driving and environmental parameters can be, for example, the current position, the current speed, the current acceleration of the motor vehicle, in particular also relative to other objects such as other motor vehicles or to static objects. Distances of the motor vehicle from lane or roadway boundaries can also be included in the driving and / or environmental parameters. Therefore, all parameters that are used as input variables for at least partially autonomous control or regulation of the motor vehicle and that can be detected by a sensor device are to be subsumed under driving and / or environmental parameters.

[0025] In particular, the electronic control and / or the sensor device is (are) supplied with electrical energy by a second electrical power supply which is independent of a first electrical power supply which supplies the parking brake circuit and / or the service brake circuit with electrical energy.

[0026] The electro-pneumatic first valve device can also be comprised by the at least one service brake circuit and designed and configured to, depending on the signal S, a) remove compressed air from the at least one compressed air supply and feed it into the at least one pneumatic service brake cylinder in order to apply the service brake, or b) vent the pneumatic service brake cylinders in order to release the service brake.

[0027] According to a further development, the electro-pneumatic first valve device can comprise at least one (in particular electrically and pneumatically controllable) relay valve or a pressure control modulator of the service brake circuit, which controls or regulates a brake pressure in at least one pneumatic service brake cylinder. The electronic control unit can also be configured to additionally generate the signal S depending on a driver action, in particular depending on the driver's actuation of a service brake actuation device.

[0028] According to a further development, the parking brake control device can comprise an electronic parking brake control, an electromagnetic parking brake valve device controlled by the latter, and an air-volume-boosting valve device with the pneumatic control connection, wherein the electromagnetic parking brake valve device is controlled by the electronic parking brake control in order to generate a control pressure for the pneumatic control connection of the air-volume-boosting valve device.

[0029] In particular, the pneumatic control connection of the air-volume-boosting valve device can be connected to the pneumatically controllable second valve device via a first pressure connection. The parking brake control device can also form a structural unit in which at least the electronic parking brake control, the electromagnetic parking brake valve device, and the air-volume-boosting valve device are integrated.

[0030] The electronic parking brake control can also be controlled depending on a parking brake control signal PS of a parking brake actuation device of the parking brake circuit. The parking brake signal can in particular represent the "parking" and "drive" states of the motor vehicle and, if necessary, the "auxiliary / emergency braking" state and / or the "test" state, in which a test is carried out to determine whether the towing vehicle, parked by the parking brake circuit, can hold the unbraked trailer stationary. To implement brake control, the brake device can comprise a trailer control valve or a trailer control module. The pneumatically controllable second valve device can also be designed and configured to block the connection between the pneumatic control port and the pressure sink in at least one second switching position.

[0031] According to a preferred embodiment, the pneumatically controllable second valve device can comprise or be formed by a pneumatically controlled 2 / 2-way valve, with an inlet which can be connected or is connected to the pneumatic control connection or to a working outlet of the air flow amplifying valve device, an outlet connected to a pressure sink and with a pneumatic control connection for a supply pressure of the at least one compressed air supply.

[0032] The pneumatically controlled 2 / 2-way valve can have two switching positions, the first switching position (pass position), which is set when the supply pressure in the at least one compressed air supply is less than the (predetermined) supply pressure limit and in which the inlet is connected to the outlet, and the second switching position (blocking position), which is set when the supply pressure in the at least one compressed air supply is greater than the (predetermined) supply pressure limit and in which the inlet is blocked from the outlet.

[0033] The inlet of the pneumatically controlled 2 / 2-way valve can be connected or connected directly or indirectly, for example via another valve device, to the control connection or to the working outlet of the air volume amplifying valve device.

[0034] Since all solenoid valves of the electro-pneumatic parking brake control device are preferably combined or arranged in the electromagnetic parking brake valve device, no solenoid valve is arranged in a control air line drawn between the outlet of the electromagnetic parking brake valve device and the pneumatic control connection of the air quantity boosting valve device, for example, the switching positions of which, depending on whether the valve is energized or not, could hinder or prevent a flow connection between the outlet of the electromagnetic parking brake valve device and the pneumatic control connection of the air quantity boosting valve device through the control air line.

[0035] Instead of a pneumatically controlled 2 / 2-way valve, a pneumatically controlled 3 / 2-way valve could also be used as a pneumatically controllable second valve device, as could any combination of pneumatically controlled 2 / 2-way valves and / or pneumatically controlled 3 / 2-way valves.

[0036] The pneumatically controlled 2 / 2-way valve, which is preferred here, is then arranged, for example, in a branch line branching off from the control air line. This has the advantage that there are no longer any solenoid valves downstream of the 2 / 2-way valve whose switching position could restrict or prevent venting of the pneumatic control port of the air-volume-boosting valve device. This increases the functional safety and reliability of the braking system.

[0037] With regard to the functionality of the electro-pneumatic braking device, the compressor, driven, for example, by an electric drive motor, counteracts a drop in the supply pressure in the at least one compressed air supply of the at least one service brake circuit caused by the application of the service brake by supplying additional pressure, provided the electrical power supply to the electric drive motor is intact, so that the (predetermined) supply pressure limit is not undercut under these circumstances. As a result, the 2 / 2-way valve remains or switches in the second switching position (blocking or drive position), in which the control air line or the pneumatic control connection of the air-volume-boosting valve device is blocked from the pressure sink.However, if, for example, the electrical power supply to the compressor's electric drive motor fails, the compressor's additional supply fails, so that upon repeated actuation of the service brake, the at least one compressed air supply of the at least one service brake circuit is emptied and the supply pressure acting as control pressure for the 2 / 2-way valve falls below the supply pressure limit. The 2 / 2-way valve then automatically switches, e.g. due to spring loading, to its first switching position (venting or parking position). In this switching position, the control air line or the pneumatic control connection of the air flow-boosting valve device is vented and the air connected to the working connection of the air flow-boosting valve device is vented.

[0038] The spring-loaded brake cylinder is applied to apply the parking brake. Since the service brake, for example, was previously applied repeatedly to bring about a condition in which the reservoir pressure falls below the reservoir pressure limit, it is assumed that the vehicle is already braked or stationary. This ensures with a high degree of probability that the parking brake will only be automatically applied when the vehicle is stationary.

[0039] The 2 / 2-way valve is preferably formed by a diaphragm valve whose opening pressure can be easily adjusted, for example, by a spring with adjustable preload. As explained above, the electropneumatic parking brake control device can be a single unit, in which case the 2 / 2-way valve or the pneumatically controllable second valve device can be integrated into this unit or can also form a separate valve device.

[0040] Particularly preferably, the 2 / 2-way valve is spring-loaded (normally closed) against the effect of the supply pressure present at its pneumatic control connection in the at least one compressed air supply into the second switching position (blocking position). If the supply pressure in the at least one compressed air supply then falls below the supply pressure limit, the spring loading of a valve element of the 2 / 2-way valve ensures automatic switching to the first switching position (passing or venting position).

[0041] Particularly preferably, the electro-pneumatic parking brake control device has at least one second output connection for a trailer control valve or a trailer control module, wherein the electromagnetic parking brake valve device is designed such that, in the event of a pressure drop in the control air line or at the pneumatic control connection of the air quantity amplifying valve device caused by the through position of the pneumatically controlled 2 / 2-way valve, a pressure signal representing the "parking" state is output to the second output connection. This pressure signal can consist of a ventilation or venting signal. Since trailer control valves or trailer control modules have an inverting effect with respect to the input pressure, when the pneumatically controllable second valve device (e.g.When the 2 / 2-way valve is switched to the first switching position (open or park position), the control pressure at the second output port for the trailer control valve is reduced, for example, thereby increasing the brake pressure for the service brakes in the trailer to the application pressure. This allows not only the spring-loaded brake cylinders of the towing vehicle but also the service brakes of the trailer to be automatically applied.

[0042] The pressure sink can be formed, for example, by a vent connection opening into the atmosphere or by at least one compressed air supply, in particular by the compressed air supply which is or has already been vented by the signal S.

[0043] Particularly when the pressure sink is formed by the at least one compressed air supply, according to a further development, a check valve is arranged in a compressed air connection between the inlet of the 2 / 2-way valve and the control air line, by means of which a desired compressed air flow from the control air line to the inlet of the 2 / 2-way valve or to the pressure sink in the through position is enabled, but an undesired compressed air flow from the inlet or the pressure sink into the control air line is prevented.

[0044] Conventional electro-pneumatic braking systems have an EBS system (electronically controlled braking system) as a service brake with at least two service brake circuits, each with its own compressed air supply, namely a first service brake circuit with a first compressed air supply and a second service brake circuit with a second compressed air supply.Preferably, such an electro-pneumatic braking device includes a selection device for further controlling the higher supply pressure from the supply pressures of the compressed air supplies (first compressed air supply, second compressed air supply) to the pneumatic control connection of the pneumatically controllable second valve device, with a first inlet connected to the first compressed air supply of the first service brake circuit, a second inlet connected to the second compressed air supply of the second service brake circuit, and an outlet connected to the pneumatic control connection of the pneumatically controllable second valve device. This selection device is formed, for example, by a shuttle valve, which then forms a logical "OR" element.

[0045] Through these measures, the control pressure for the pneumatically controllable second valve device is generated by the higher supply pressure of the service brake circuits, so that the failure of a single service brake circuit, e.g. due to a leak, does not lead to a supply pressure in this service brake circuit that is below the supply pressure limit and then causes an unnecessary switching of the pneumatically controllable second valve device to the first switching position (pass or park position), since such a leak does not necessarily constitute a reason to forcibly bring the vehicle into the safe park position. These measures therefore improve the functional reliability of the electro-pneumatic braking system.

[0046] According to a further development, a throttle device is provided between the first compressed air supply and the first inlet of the selection device and between the second compressed air supply and the second inlet of the selection device, the throttle cross-section of which is at least so small that a volume flow that has unintentionally arisen between the first inlet and the second inlet of the selection device is smaller than a minimum delivery volume flow that the compressor is able to supply to the compressed air supplies with minimal delivery capacity. Such an undesired volume flow between the first inlet and the second inlet of the selection device can arise, for example, due to an intermediate position of the selection device or the shuttle valve. These measures therefore also improve the functional reliability of the electropneumatic braking device.

[0047] The invention also relates to a motor vehicle with an electropneumatic braking system described above, in particular a commercial vehicle designed as a towing vehicle and equipped for trailer operation. Further measures improving the invention are described in more detail below, together with the description of an exemplary embodiment of the invention, with reference to the drawing.

[0048] drawing

[0049] In the drawing, the single figure shows a schematic circuit diagram of a section of an electro-pneumatic braking device of a towing vehicle of a towing vehicle-trailer combination according to a preferred embodiment of the invention;

[0050] Description of the Embodiment The figure shows a section of an electro-pneumatic braking system 1 of a towing vehicle-trailer combination with a service brake and parking brake. The electro-pneumatic braking system 1 preferably comprises a brake system (EBS) with electronically controlled brake pressure as the service brake.

[0051] The electro-pneumatic braking device 1 is supplied with compressed air in a known manner by a compressor 2, driven here, for example, by an electric drive motor 89. For this purpose, the compressor 2 is connected to two compressed air reservoirs 8, 10 via two compressed air supply lines 4, 6, each of the compressed air reservoirs 8, 10 being assigned, for example, to a service brake circuit of the service brake. Between the compressor 2 and the compressed air reservoirs 8, 10, an overflow valve 12, 14 with a known purpose and function is arranged in each of the compressed air supply lines 4, 6. This creates a circuit separation.

[0052] A further element of the service brake circuits can be an optional service brake actuation device 95, here, for example, a foot brake module, which enables the driver to actuate the service brake and feeds an actuation-dependent service brake request signal into an electronic control unit 100, in which, for example, an EBS brake control unit is integrated. Depending on the service brake request signal, the EBS brake control unit then controls an electro-pneumatic first valve device, which here, for example, comprises a first pressure control module 90a and a second pressure control module 90b, in order to draw compressed air from the two compressed air reservoirs 8, 10 and supply it to service brake cylinders 91a, 91b. The service brake actuation device 95, which can be actuated by the driver, can also be omitted if the service brake circuits are actuated exclusively by an autonomously generated service brake request signal.

[0053] From the two compressed air supply lines 4, 6 of the two

[0054] A compressed air supply line 20 for a parking brake circuit branches off from the service brake circuits. The parking brake is thus supplied with compressed air from the compressed air supplies 8 and 10 of the service brake circuits. Alternatively, a separate compressed air supply could also be provided for the parking brake circuit.

[0055] An overflow valve 24 and a check valve 26 are arranged in the compressed air supply line 20 of the parking brake circuit to protect the circuit. The compressed air supply line 20 of the parking brake circuit is also connected to a supply connection 28 of an electro-pneumatic parking brake control device 30, with which various functions or states related to the parking brake can be controlled, in particular known states or functions such as "drive," "park," "test," "extension brake," and "auxiliary or emergency brake."

[0056] Since the electro-pneumatic parking brake control device 30 is preferably designed as a modular unit and can be connected as such to the electro-pneumatic braking device 1, it can also be referred to as an Electronic Parking Brake Module (EPBM). For example, two spring-loaded brake cylinders 33 on the rear axle of the towing vehicle are connected to a first output port 32 of the electro-pneumatic parking brake control device 30. A second output port 34 is connected to an electro-pneumatic trailer control valve or module 22, which controls the trailer brakes.

[0057] The electro-pneumatic parking brake control device 30 includes an electromagnetic parking brake valve device 36, shown here only in a simplified manner as a box, with solenoid valves such as inlet valve, outlet valve, bistable valve, etc., through which, among other things, a pneumatic control pressure is generated at a connection 38 for a pneumatic control connection 40 of a relay valve 42, whose working output 44 is connected to the first output connection 32. Furthermore, the second output connection 34 for the trailer control module 22 is connected to the

[0058] Parking brake valve device 36 is controllably connected. The electro-pneumatic parking brake control device 30 includes an electronic parking brake control 46 for controlling the solenoid valves of the electro-pneumatic parking brake valve device 36, depending, among other things, on parking brake signals PS input via a parking brake signal connection 48, which are generated by a driver-operated parking brake signal generator 50, such as a rocker switch or operating lever. Furthermore, signals from integrated sensor devices, such as pressure sensors, are fed into the electronic parking brake control 46. These sensors measure the actual pressures at the output connections 32, 34 in order to implement parking brake pressure control through a target-actual value comparison in the parking brake control 46, as is advantageous, for example, in the context of auxiliary braking.The pneumatic part of the electromagnetic parking brake valve device 36 is supplied with the compressed air of the parking brake circuit through the supply connection 28.

[0059] The control port 40 of the relay valve 42 is connected to the outlet 38 of the electromagnetic parking brake valve device 36 via a control air line 52, and a supply inlet 54 is connected to the supply port 28 via a compressed air connection 56. Based on the supply pressure, it modulates a working pressure at its working outlet 44 depending on the control pressure prevailing in the control air line 52 and controlled by the electromagnetic parking brake valve device 36. This working pressure is then fed into the spring brake cylinders 33 via the first output port 32. To apply the spring brake cylinders 33, the first output port 32 is vented and to release it, it is vented.

[0060] Since all solenoid valves or electrically actuated components are preferably combined in the electromagnetic parking brake valve device 36, there are preferably no solenoid valves in the control air line 52. However, a shuttle valve in the control air line is conceivable, which, for anti-compound reasons, controls the greater pressure from the control pressure controlled by the parking brake valve device 36 and a service brake pressure controlled via a service brake pressure connection (not shown here) to the control connection 40 of the relay valve 42. A corresponding third output connection 53 is provided on the parking brake control device 30 for connecting the first pressure connection 62 to the parking brake control device 30.

[0061] Furthermore, the braking device comprises, for example, a pneumatically controlled 2 / 2-way valve 58, with an inlet 60, which here is preferably connected directly or immediately via a first pressure connection 62 to the control air line 52, an outlet 64 connected to a pressure sink 68, and a pneumatic control connection 66 for a supply pressure of the service brake. In the embodiment shown in the figure, the pressure sink is formed, for example, by a vent 68 of the 2 / 2-way valve 58.

[0062] As shown in the figure by the first pressure connection 62' shown as a dot-dash line, the inlet 60 of the pneumatically controlled 2 / 2-way valve 58 can alternatively be connected or connectable to the working output 44 of the relay valve 42 or to the first output port 32, if necessary also by means of another valve device. A corresponding port 53' is then provided. Alternatively, the first pressure connection 62' could also be connected to the first output port 32.

[0063] The pneumatically controlled 2 / 2-way valve 58 has two positions: a first switching position (open or park position), which occurs when the supply pressure in at least one of the compressed air supplies 8, 10 at the control port 66 is less than, for example, a predetermined supply pressure limit, and in which the inlet 60 is connected to the outlet 64; and a second switching position (blocking or drive position), which occurs when the supply pressure in at least one of the compressed air supplies 8, 10 is greater than the supply pressure limit, and in which the inlet 60 is blocked from the outlet 64. The 2 / 2-way valve 58 is preferably a diaphragm valve controlled by the control pressure at its pneumatic control port 66, which is spring-loaded, for example, into its first switching position (open or park position).If the supply pressure then falls below the supply pressure limit, the spring load of a valve element connected to the diaphragm ensures that the 2 / 2-way valve 58 automatically switches to the first switching position (open or park position). However, if the supply pressure at its pneumatic control port 66 is greater than or equal to the supply pressure limit, the valve element is forced into the second switching position (blocking or drive position) by the supply pressure.

[0064] The 2 / 2-way valve 58, which here merely serves as an example of a pneumatically controllable valve device and preferably represents a separate structural unit, can also be integrated into the electropneumatic parking brake control device 30.

[0065] The first pressure connection 62 branches off from the control air line 52 at a point between the outlet 38 of the electromagnetic parking brake valve device 36 and the control connection 40 of the relay valve 42, so that, for example, the control connection 40 of the relay valve 42 is connected directly to the inlet 60 of the 2 / 2-way valve 58 without the need for any further interposition of solenoid valves. In this respect, the connection of the inlet 60 of the 2 / 2-way valve 58 to the control connection 40 of the relay valve 42 can certainly be described as direct.

[0066] Preferably, a selection device is provided here in the form of a shuttle valve 72 (Select High) for further controlling the higher supply pressure from the supply pressures of the compressed air supplies 8, 10 to the pneumatic control port 66 of the 2 / 2-way valve 58. For this purpose, the pneumatic control port 66 is connected via a second pressure connection 74 to an outlet 76 of the shuttle valve 72, whose first inlet 78 is connected to the first compressed air supply 8 of the first service brake circuit and whose second inlet 80 is connected to the second compressed air supply 10 of the second service brake circuit.

[0067] The shuttle valve 72 then forms a logical “OR” element with respect to the supply pressures in the compressed air supplies 8, 10. Through these measures, the control pressure for the 2 / 2-way valve 58 is formed by the higher supply pressure of the service brake circuits.

[0068] Particularly preferably, a throttle device 82, 84 is provided between the first compressed air supply 8 and the first inlet 78 of the shuttle valve, and between the second compressed air supply 10 and the second inlet 80 of the shuttle valve. The throttle cross-section of both throttle devices 82, 84 is at least so small that a volume flow that has unintentionally arisen between the first inlet 78 and the second inlet 80 of the shuttle valve 72, for example due to an undefined intermediate position of the valve member of the shuttle valve 72, is smaller than a minimum delivery volume flow that the compressor 2 is capable of supplying to the compressed air supplies 8, 10 with minimal delivery capacity.

[0069] The parking brake control device 30 and the electric drive motor 89 of the compressor 2 are supplied with power here by a first electrical energy source such as a battery 86.

[0070] The electro-pneumatic braking device further comprises the first pressure control module 90a in the first service brake circuit and the second pressure control module 90b in the second service brake circuit, wherein the first pressure control module 90a is supplied with compressed air from the first compressed air supply 8 and the second pressure control module 90b is supplied with compressed air from the second compressed air supply 10.

[0071] The two pressure control modules 90a, 90b are controlled by an electronic control unit 100, which here comprises, for example, the EBS brake control unit, in order to regulate a target service brake pressure in the respectively connected first and second pneumatic service brake cylinders 91a, 91b depending on a brake request signal S generated autonomously, i.e. without action by the driver. The brake request signal S generated autonomously here therefore contains the information about the target service brake pressure in the first and second pneumatic service brake cylinders 91a, 91b. Here, for example, in addition to the EBS brake control unit, an electronic autopilot control is therefore integrated into the electronic control unit 100, which then generates the electrical brake request signal S for the pressure control modules 90a, 90b autonomously, i.e. without action by the driver, i.e. without actuation of the foot brake module, which is additionally present here, for example.The braking request signal S can be generated automatically depending on any circumstances which are in particular independent of any action by the driver, for example as a braking request signal S generated autonomously by the electronic autopilot control and / or as a braking request signal S generated depending on a sensor signal FS, as will be explained further below.

[0072] The pressure control modules 90a, 90b are constructed in a known manner and each comprise an integrated electronic control unit, an integrated inlet-outlet valve combination electrically controlled by the latter, an integrated relay valve pneumatically controlled by the latter, and an integrated pressure sensor that feeds the actual service brake pressure output by the relay valve into the integrated electronic control unit for comparison with the desired service brake pressure. A backup solenoid valve can also be integrated, which, during normal operation, retains a pneumatic control pressure output by the driver-operated foot brake module (not shown here) and only switches it through to the control connection of the relay valve in the event of a failure of the electrical control unit.

[0073] The electronic control system 100 receives sensor signals FS from a sensor device 92, which here represent, for example, error signals, errors or failures of the first electrical power supply 86. For this purpose, the sensor device 92 is connected to the first electrical power supply 86 via a signal line 93 and measures, for example, its electrical voltage.

[0074] The electronic control 100, the sensor device 92 and the first and second pressure control modules 90a, 90b are supplied with electrical energy here, for example, by a second electrical energy supply 94 which is independent of the first electrical energy supply 86.

[0075] Against this background, the functioning of the braking device 1 here, for example, with regard to the functionality of the first electrical power supply 86, is as follows:

[0076] When the intact first electrical power supply 86 is detected by the sensor device 92 and reported to the electronic control 100 (e.g. voltage U greater than or equal to a permissible lower voltage limit value llgrenz), the electric drive motor 89 drives the compressor 2 in order to counteract the reduction in the supply pressure in the compressed air supplies 8, 10 of the two service brake circuits caused by a brake request signal S generated by actuating the brake pedal of the foot brake module or by the electronic control 100 by means of additional supply, so that the supply pressure limit value is not undershot under these circumstances. As a result, the 2 / 2-way valve 58 remains or switches in the second switching position (locking or drive position), in which the control air line 52 of the relay valve 42 is blocked from the pressure sink 68.The electronic control 100 then does not generate an autonomous braking request signal S solely depending on the signals supplied by the sensor device 92, because it evaluates these signals to the effect that the first electrical energy supply 86 is intact.

[0077] However, in the event of a failure of the first electrical power supply 86 (voltage U less than the permissible lower voltage limit llgrenz) detected by the sensor device 92 and reported to the electronic control 100 by the then generated sensor signal FS, the electric drive motor 89 of the compressor 2 fails, and thus also the subsequent supply of compressed air into the compressed air reservoirs 8, 10 by the compressor 2. Furthermore, the parking brake circuit can then no longer be actuated by the parking brake signal transmitter 50.

[0078] In response to the sensor signal FS generated here as an error signal by the sensor device 92, the electronic control unit 100 then automatically generates, for example, at least one brake request signal S for the two pressure control modules 90a, 90b, which then draw compressed air from the compressed air reservoirs 8, 10 and use this to modulate or adjust the regulated brake pressure for the pneumatic service brake cylinders. Preferably, the electronic control unit 100 automatically generates several successive brake request signals S so that the motor vehicle is braked to a low speed or to a standstill, and the compressed air reservoirs 8, 10 are emptied over time. As a result, the supply pressure acting as the control pressure for the 2 / 2-way valve 58 drops below the supply pressure limit value, whereupon the valve switches to its first switching position (Fig. 1), in which the control connection 40 of the relay valve 42 is connected to the pressure sink 68.As explained above, this vents the spring brake cylinders 33 and automatically applies the parking brake of the towing vehicle, which automatically transfers the towing vehicle to the safe parked state.

[0079] Since the second electrical power supply 94 remains intact, the sensor device 92, the electronic control 100 and the pressure control modules 90a, 90b can operate as described above.

[0080] The pressure drop in the control air line 52 is also fed via the connection 38 into the parking brake valve device 36, which is designed such that, in the event of such a pressure drop at its connection 38, it feeds a pressure signal representing a parking position to the second output connection 34 for the trailer control valve 22. This pressure signal can consist of a ventilation or venting of the second connection 34, depending on whether the trailer brakes are to be applied or released when parked. The pressure drop in the control air line 52 or at the connection 38 ensures, for example, at a pneumatic control input of a (likewise) pneumatically controlled bistable valve within the parking brake valve device 36, that the bistable valve outputs the pressure signal representing the parking position to the second output connection 34 for the trailer control valve 22.

[0081] Preferably, the trailer brakes should also be applied when parking. Since trailer control valves 22 have an inverting effect with respect to the input pressure, when the 2 / 2-way valve 58 is switched to the through or park position due to the failure of the electrical power supply 86 and the resulting pressure drop in the control air line and thus at port 38, the parking brake valve device 36 is controlled such that the control pressure at the second output port 34 and also at the trailer control valve 22 is reduced, thereby increasing the brake pressure for the brakes in the trailer to the application pressure. As a result, in the event of a failure of the first electrical power supply 86, not only the spring-loaded brake cylinders 33 of the towing vehicle but also the service brakes of the trailer are automatically applied.

[0082] The shuttle valve 72 forms the control pressure for the 2 / 2-way valve 58 by the higher supply pressure of the service brake circuits, so that a failure of a single service brake circuit, e.g. due to a leak, does not lead to a supply pressure in this service brake circuit that is below the pressure limit value and then leads to an unnecessary switching of the 2 / 2-way valve 58 into the through or parking position, since in such a leakage case there does not necessarily have to be a failure of the first electrical energy supply 86.

[0083] However, with reference to the above case in which the first electrical power supply 86 has failed and the parking brake circuit can then no longer be actuated, monitoring of the functionality of the first electrical power supply 86 by a sensor device 92 is not absolutely necessary in order to automatically generate a brake request signal S, which then leads to a pressure drop in the compressed air tanks 8, 10.

[0084] For example, if the brake request signal S is generated autonomously by the electronic autopilot control, which is integrated here, for example, in the electronic control 100, in particular during at least one autonomously triggered service braking, this also results in the supply pressure in the compressed air reservoirs 8, 10 falling below the supply pressure limit, whereupon the 2 / 2-way valve 58 is also controlled to the first switching position (open or park position). The service braking can be triggered autonomously, for example, depending on driving and environmental parameters, which are then in turn detected by a sensor device.

[0085] In other words, only at least one autonomously triggered service brake ensures that the towing vehicle is braked to a low speed or to a standstill using the service brake automatically and in particular without any intervention or action by the driver and then the parking brake is also automatically applied in order to establish a safe parked state of at least the towing vehicle.

[0086] Therefore, the electronic controller 100 is designed and configured to automatically generate the signal S, here as a brake request signal S (also) independently of an actuation of the service brake actuation device 95 by a driver of the motor vehicle. In addition, however, the option should still be available for the electronic controller 100 to generate the brake request signal S (also) depending on an actuation of the service brake actuation device 95 by the driver of the motor vehicle.

[0087] 1 electro-pneumatic braking device

[0088] 2 compressors

[0089] 4 Compressed air supply line

[0090] 6 Compressed air supply line

[0091] 8 Compressed air supply

[0092] 10 Compressed air supply

[0093] 12 Overflow valve

[0094] 14 Overflow valve

[0095] 20 Compressed air supply line

[0096] 22 Trailer control valve

[0097] 24 Overflow valve

[0098] 26 Check valve

[0099] 28 Supply connection

[0100] 30 Parking brake control device

[0101] 32 first output connection

[0102] 33 spring brake cylinders

[0103] 34 second output connection

[0104] 36 Parking brake valve device

[0105] 38 connection

[0106] 40 control connection

[0107] 42 Relay valve

[0108] 44 Work exit

[0109] 46 Parking brake control

[0110] 48 Parking brake signal connection

[0111] 50 parking brake signal transmitters

[0112] 52 Tax! air line

[0113] 53 third output connection

[0114] 54 Supply entrance

[0115] 56 Compressed air connection 58 2 / 2-way valve

[0116] 60 entrance

[0117] 62 first pressure connection

[0118] 64 Outlet

[0119] 66 control connection

[0120] 68 Ventilation

[0121] 72 shuttle valve

[0122] 74 second pressure connection

[0123] 76 Outlet

[0124] 78 first entry

[0125] 80 second entrance

[0126] 82 Throttle device

[0127] 84 Throttle device

[0128] 86 first electrical power supply

[0129] 89 electric drive machine

[0130] 90a first pressure control module

[0131] 90b second pressure control module

[0132] 91a first pneumatic service brake cylinders

[0133] 91 b second pneumatic service brake cylinder

[0134] 92 Sensor device

[0135] 93 Signal line

[0136] 94 second electrical power supply

[0137] 95 Service brake actuation device

[0138] 100 electronic control

[0139] S Signal

[0140] FS sensor signal

[0141] PS parking brake signal

Claims

PATENT CLAIMS 1. Electro-pneumatic braking device (1 ) of a motor vehicle, which comprises at least the following: a) an electro-pneumatic parking brake circuit with Spring brake cylinders (33) and a parking brake control device (30) with a pneumatic control connection (40), wherein the Parking brake control device (30) is designed and arranged to, when the pneumatic control connection (40) is ventilated, to release the spring-loaded brake cylinder (33) and to apply it when the pneumatic control connection (40) is vented, b) at least one service brake circuit, which comprises service brake cylinders (91a, 91b) consuming compressed air and at least one compressed air reservoir (8, 10) under reservoir pressure, which provides the compressed air for the service brake cylinders (91a, 91b), c) an electro-pneumatic first valve device (90a, 90b) controlled by an electronic control (100) by a signal (S), which is designed and configured to withdraw compressed air from the at least one compressed air reservoir (8, 10) depending on the signal (S) of the electronic control (100) and to supply it to the service brake cylinder (91a, 91b), a pressure sink and / or a compressed air consumer, d) a pneumatically controllable second valve device (58), which is designed and configuredin order to connect the pneumatic control connection (40) of the parking brake control device (30) to a pressure sink (68) in at least one first switching position, wherein e) the pneumatically controllable second valve device (58) is controlled directly or indirectly by the supply pressure prevailing in the at least one compressed air supply (8, 10) in such a way that it assumes the first switching position when the supply pressure falls below a supply pressure limit value, characterized in that, f) the electronic control (100) is designed and configured to automatically generate the signal (S) independently of an actuation of the at least one service brake circuit by a driver of the motor vehicle.

2. Braking device according to claim 1, characterized in that the electronic control (100) comprises or forms a) an electronic service brake control unit, and / or b) a redundant electronic service brake control unit, and / or c) an electronic autopilot control unit.

3. Braking device according to claim 1 or 2, characterized in that the electronic control (100) is designed and configured to automatically generate the signal (S) as a function of a sensor signal (FS) supplied by a sensor device (92).

4. Braking device according to claim 3, characterized in that the sensor signal (FS) supplied by the sensor device (92) comprises an error signal which indicates at least one of the following failures or errors or irregular states: a) a failure or error or irregular state of the parking brake circuit and / or of the at least one service brake circuit, and / or b) a failure or error or irregular state of a power supply of the parking brake circuit and / or of the at least one service brake circuit, and / or c) a failure or error or irregular state of a Drive device (89) which has a at least one Compressed air supply (8, 10) drives the compressor (2) supplying compressed air, and / or d) a failure or error or irregular condition of the compressor (2), and / or e) no or no plausible value for the supply pressure prevailing in the at least one compressed air supply (8, 10).

5. Braking device according to claim 3 or 4, characterized in that the sensor signal (FS) supplied by the sensor device (92) comprises a signal generated as a function of driving and / or environmental parameters of the motor vehicle.

6. Braking device according to one of claims 3 to 5, characterized in that the electronic control (100) and / or the sensor device (92) is supplied with electrical energy by a second electrical power supply (94) which is independent of a first electrical power supply (86) which supplies the parking brake circuit and / or the service brake circuit with electrical energy.

7. Braking device according to one of the preceding claims, characterized in that the electro-pneumatic first valve device (90a, 90b) is comprised by the at least one service brake circuit and is designed and configured to, depending on the signal (S), a) take compressed air from the at least one compressed air supply (8, 10) and feed it into the at least one pneumatic service brake cylinder (91a, 91b) in order to apply the service brake, or b) vent the pneumatic service brake cylinders (91a, 91b) in order to release the service brake.

8. Braking device according to claim 7, characterized in that the electro-pneumatic first valve device (90a, 90b) comprises at least one relay valve or a pressure control modulator of the service brake circuit which controls or regulates a brake pressure in at least one pneumatic service brake cylinder (91a, 91b).

9. Braking device according to one of the preceding claims, characterized in that the electronic control (100) is designed to generate the signal (S) additionally depending on an action of the driver, in particular depending on an actuation of a service brake actuating device (95) by the driver.

10. Braking device according to one of the preceding claims, characterized in that the parking brake control device (30) comprises an electronic parking brake control (46), an electromagnetic parking brake valve device (36) controlled by the latter, and an air-quantity-boosting valve device (42) with the pneumatic control connection (40), wherein the electromagnetic parking brake valve device (36) is controlled by the electronic parking brake control (46) in order to generate a control pressure for the pneumatic control connection (40) of the air-quantity-boosting valve device (42).

11. Braking device according to claim 10, characterized in that the electronic parking brake control (46) is controlled as a function of a parking brake control signal (PS) of a parking brake actuating device (50) of the parking brake circuit.

12. Braking device according to one of the preceding claims, characterized in that the pneumatically controllable second valve device (58) is designed and configured to block the connection between the pneumatic control connection (40) and the pressure sink (68) in at least one second switching position.

13. Braking device according to one of the preceding claims, characterized in that a pneumatic control connection (66) of the pneumatically controllable second valve device (58) is connected directly or indirectly to the at least one compressed air supply (8, 10).

14. Braking device according to claim 13, characterized in that at least two service brake circuits are provided, each with its own compressed air supply (8, 10), namely a first Service brake circuit with a first compressed air supply (8) and a second service brake circuit with a second compressed air supply (10), wherein a selection device (72) is provided for further controlling the higher supply pressure from the supply pressures of the compressed air supplies (8, 10) to the pneumatic control connection (66) of the pneumatically controllable second valve device (58), with a first inlet (78) connected to the first compressed air supply (8) of the first service brake circuit, a second inlet (80) connected to the second compressed air supply (10) of the second service brake circuit and an outlet (76) connected to the pneumatic control connection (66) of the pneumatically controllable second valve device (58).

15. Braking device according to claim 14, characterized in that the selection device (72) is formed by a shuttle valve.

16. Motor vehicle with an electro-pneumatic braking device according to one of the preceding claims.

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