Relay valve, electropneumatic control device, and brake system

Abstract

The present invention relates to a relay valve (18) for an electropneumatic control device (1), the relay valve comprising: a pneumatic control inlet (20) which is connected to a control chamber (42) of the relay valve (18); a working outlet (28) which is connected to a working chamber (58) of the relay valve (18); at least one first throttle element (30) which connects the working chamber (58) and the control chamber (42) to one another; a supply inlet (16) which is connected to a supply chamber (60) of the relay valve (18); a double-seat valve (50, 54) having at least one inlet seat (54) and at least one outlet seat (50); a relay piston (46) for actuating the double-seat valve (50, 54), wherein the working chamber (58) is connected to a vent (56) when the outlet seat (50) is open, and to the supply chamber (60) when the inlet seat (54) is open, and wherein the relay valve (18) further comprises at least one second throttle element (65, 65', 65", 65''', 65'''', 65''''') which is arranged in such a way that the working chamber (58) and the vent (56) are in throttled fluidic connection with one another via the at least one second throttle element (65, 65', 65", 65''', 65'''', 65''''') at least in an intermediate position of the relay piston (46) between the venting position and the supply position, and such that the at least one second throttle element (65, 65', 65", 65''', 65'''', 65''''') is fully closed in the supply position.

Description

[0001] DESCRIPTION

[0002] Relay valve, electropneumatic control unit and brake system

[0003] The present invention relates to a relay valve for an electropneumatic control device, an electropneumatic control device for controlling at least one pneumatic device with such a relay valve, and a braking system of a vehicle with such an electropneumatic control device.

[0004] In vehicles, especially commercial vehicles including tractor-trailer combinations and rail vehicles, parking brakes (also called hand brakes) are equipped with spring-applied brake cylinders as exemplary pneumatic devices. In the released position, these cylinders pressurize a spring compression chamber with compressed air, thereby keeping the spring under tension. To brake, the spring compression chamber is vented, i.e., connected to atmospheric pressure, so that the brake cylinder generates a braking force under the action of the spring.

[0005] Both purely pneumatically operated parking brakes, which are operated by a bistable parking brake valve actuated by the driver, and electropneumatic systems with a bistable electromechanical valve, for example a pneumatic relay valve controlled by an electromechanical bistable solenoid valve, are known. Both valve positions for "parking brake" and "release" must be "stable," meaning they must remain in their respective end positions without human intervention or electrical energy.

[0006] In the state of the art, bistability is therefore achieved either purely pneumatically with downstream relay valves and several actuating and regulating pistons, for example according to DE 10 2009 016 983 A1 or DE 10247 812 C1, which is complex and requires a large installation space, or via bistable solenoid valves with a downstream relay valve, as described in DE10 2006 055 570 B4. However, bistable solenoid valves are expensive and prone to failure in practice.

[0007] From the generic WO 2015 / 154787 A1, it is known to achieve bistability in an electric parking brake with a relay valve by means of a feedback line from the relay valve output to the control chamber of the relay valve, wherein a throttle is arranged in the feedback path. This results in bistable behavior of the relay valve, which maintains its currently adopted position, such as "Park" or "Drive," even without power supply to the solenoid valve assembly controlling the relay valve. The solenoid valve assembly comprises two 2 / 2-way solenoid valves, an inlet solenoid valve and an outlet solenoid valve, and is used to vent or purge a control chamber of the relay valve. The relay valve piston is in the purge position for the "Park" state when the control pressure in the control chamber is below a certain threshold.The working port of the relay valve is connected to a vent. The control chamber is then also connected to the vent via the throttle in the feedback line, through the working port of the relay valve. Conversely, the relay valve piston is in the vent position for the "driving" state when the control pressure in the control chamber exceeds a certain threshold. The working port of the relay valve is connected to the pressure supply. The control chamber is also connected to the pressure supply via the throttle in the feedback line. For the "graduated braking" state, the inlet and outlet solenoid valves are controlled, allowing a pressure between 0 bar and the supply pressure to establish itself in the control chamber of the relay valve. The relay valve piston is then in an intermediate position between the vent position and the open position.At the working output of the relay valve, a pressure proportional to the control pressure in the control chamber is applied to the spring-applied parking brakes. The parking brake can then be used as an emergency or auxiliary brake, even while driving, with a braking force adjustable via the parking brake actuator.

[0008] However, a power failure during the application of the emergency or auxiliary braking function can lead to different brake pressures in the spring-applied brakes, depending on the brake pressure present at the time of the power failure. Several scenarios are conceivable: a) Firstly, during a power failure, so much control air can flow into the control chamber of the relay valve via the restrictor in the feedback line that the supply pressure is established in both the control chamber and the spring-applied brakes. The "driving" state is then stable, and the relay valve piston is in the venting position. b) Furthermore, during a power failure, the same pressure can be established in the control chamber of the relay valve and in the spring-applied brakes, so that no compensating flow occurs via the restrictor in the feedback line.The current pressure in the spring-applied brakes is then maintained, so that neither the "Driving" nor the "Parking" state is stably assumed. The relay valve piston is then in an intermediate position as described above. c) In addition, in the event of a power failure, compressed air can flow from the control chamber via the throttle in the feedback line into the spring-applied brakes, so that both the control chamber and the spring-applied brakes are vented. The "Parking" state is then stably maintained, and the relay valve piston is in the venting position.

[0009] Case b) above is problematic because, in the event of a power failure during the execution of the emergency or auxiliary braking function, the pressure in the spring-applied brakes is maintained. However, the "parking" state can then no longer be reached.

[0010] To address the aforementioned problem, EP 3 678 909 A1 discloses an electropneumatic parking brake control device for controlling a parking brake comprising at least one spring-applied brake cylinder, including a relay valve with a control chamber and a vent. Depending on the position of the relay piston, the control chamber can be connected to the vent via at least one throttle element.

[0011] In general, a relay valve can be considered a pneumatic amplifier, where a small flow rate in the control chamber of the relay valve regulates the pressure, which then determines the pressure applied to a working outlet with a large flow rate. The pressure regulation in the control chamber is achieved using solenoid valves with small internal cross-sections. Bores that vent from the control chamber to the outside, as in EP 3 678 909 A1, complicate pressure regulation. In particular, the solenoid valves must be able to introduce more air into the control chamber than leaks out through the throttling element. This pressure loss can lead to a slow pressure increase in the control chamber, potentially preventing the fulfillment of requirements for a rapid pressure increase, such as for quickly releasing the parking brake.

[0012] The object of the invention is to provide a control via a relay valve that makes it possible to maintain a stable "parking" state, while avoiding or at least reducing the influence on pressure regulation in the control chamber.

[0013] The problem is solved by the subject matter of the subordinate claims. Advantageous further developments are the subject matter of the dependent claims.

[0014] According to the invention, a relay valve for an electropneumatic control device has a pneumatic control inlet connected to a control chamber of the relay valve and a working outlet connected to a working chamber of the relay valve, wherein at least one first throttling element is arranged such that the working chamber and the control chamber are in throttled flow communication with each other. Furthermore, the relay valve has a supply inlet connected to a supply chamber of the relay valve, a double-seat valve with at least one inlet seat and at least one outlet seat, and a relay piston for actuating the double-seat valve, which is movable within a relay valve housing between a vented position and a vented position depending on the pressure in the control chamber.In the venting position, the relay piston actuates the double-seat valve such that the outlet seat is fully open and the inlet seat is fully closed. In the venting position, the relay piston actuates the double-seat valve such that the outlet seat is fully closed and the inlet seat is fully open. When the outlet seat is open, the working chamber is connected to a vent, and when the inlet seat is open, it is connected to the reservoir chamber. The relay valve has at least one second throttling element, which is arranged such that, at least in an intermediate position of the relay piston between the venting and venting positions, the working chamber and the vent are in a throttled flow connection via this second throttling element, and that this second throttling element is fully closed in the venting position.

[0015] The basic concept of the invention, as well as further embodiments of the relay valve, are described below using the example of a relay valve for an electropneumatic control device, which is designed as an electropneumatic parking brake control device for controlling a parking brake comprising at least one spring-applied brake cylinder. However, the relay valve, as well as the electropneumatic control device and / or brake position for a vehicle discussed later, are not limited to a parking brake application or to specific design features given as examples, unless this is essential.

[0016] Starting with the exemplary parking brake control device for controlling a parking brake containing at least one spring-applied brake cylinder as an electropneumatic control device, the vented position of the relay piston, for example, causes a pressure to be present at a connection for the at least one spring-applied brake cylinder, which is fluidically connected to the working chamber. This pressure corresponds to the clamping pressure of the at least one spring-applied brake cylinder when it is fully clamped. In the corresponding configuration of the relay valve, the vented position of the relay piston causes a pressure to be present at the connection for the at least one spring-applied brake cylinder. This pressure corresponds to the release pressure of the at least one spring-applied brake cylinder when it is fully released.An intermediate position of the relay piston then causes a pressure to be present at the connection for at least one spring-applied brake cylinder, which is greater than the clamping pressure but less than the release pressure. Several intermediate positions of the relay piston can exist, depending on the required parking brake force during an emergency or auxiliary braking maneuver.

[0017] For the purpose of feedback, the at least one first throttling element is therefore arranged between the working chamber and the control chamber such that the working chamber and the control chamber are always in flow communication with each other. This connection can be direct or indirect via a feedback line. For example, the at least one first throttling element can be arranged in the feedback line between the working outlet and the pneumatic control input of the relay valve, such that the working outlet and the pneumatic control input of the relay valve are always in flow communication with each other. A feedback circuit is created via the at least one first throttling element or the feedback line equipped with the at least one first throttling element, in which the pressure in the working chamber or at the working outlet of the relay valve is modulated.at the connection for which at least one spring-loaded brake cylinder is fed back into the control chamber or into the control input of the relay valve.

[0018] A throttling element is generally understood to be an element that limits a flow cross-section, for example, in the case of a feedback line, an element that narrows the flow cross-section of the feedback line. In the case of a feedback line, the air mass flow through the throttling element (in both flow directions) is limited to a value that is, for example, lower than the air mass flow that would flow through the line without the throttling element. The flow cross-section provided by the throttling element is therefore smaller than the flow cross-section provided by the line. In a state where a compensating flow occurs across the at least one first throttle due to a pressure equilibrium, the instantaneous pressure in the working chamber is maintained, so that neither a venting position nor a purging position can be stably assumed.Applied to the aforementioned electropneumatic parking brake control device, neither the "Driving" nor the "Parking" state is stably maintained. The relay valve piston is then in an intermediate position. To move the relay piston into the venting position in such a situation, at least one second throttle valve is provided, which connects the working chamber to the vent in at least one intermediate position of the relay piston. With reference to the exemplary parking brake control device, the at least one second throttle element ensures that, for example, in the event of a power failure during an emergency or auxiliary braking function, in which the relay piston assumes an intermediate position, the control pressure in the working chamber of the relay valve drops, thereby also reducing the brake pressure in the spring-applied brakes and consequently stably maintaining the "Parking" state.

[0019] Because the venting position can be achieved by venting the working chamber and not the control chamber, the regulation of the pressure in the control chamber is not affected by at least one second throttling element.

[0020] In one embodiment, the at least one second throttling element is arranged such that the working chamber and the vent are in throttled flow communication with each other via the at least one second throttling element in the venting position of the relay piston and in the at least one intermediate position of the relay piston between the venting position and the ventilation position.

[0021] Accordingly, venting via the at least one second throttling element occurs not only in at least one intermediate position of the relay piston, but also in the venting position of the relay piston. The at least one second throttling element may not make a significant contribution to venting, for example, due to its small flow cross-section compared to the venting cross-section formed by the open outlet seat. In such a configuration, however, at least a simple design of the at least one second throttling element can be used. Alternatively, a flow cross-section for the at least one second throttling element can be provided that is larger in the venting position than in an intermediate position, so that the larger flow cross-section in the venting position can result in faster venting.This can be implemented, for example, by progressively reducing the size of at least one opening of at least one second throttling element during a movement from the venting position to an intermediate position, such as by increasing overlap in an overlap area with a corresponding contact surface.

[0022] In one embodiment, the vent is at least partially formed by an outlet seat guide on which the outlet seat is movable between a fully open position and a fully closed position. The outlet seat and the outlet seat guide have an overlap area in the direction of movement from the fully open to the fully closed position of the outlet seat. The at least one second throttling element is arranged in a section of the overlap area formed by the outlet seat and / or in a section of the overlap area formed by the outlet seat guide.

[0023] When the exhaust seat is moved by the relay piston in the direction of movement from the fully open to the fully closed position of the exhaust seat, a relative movement takes place between the exhaust seat and the exhaust seat guide.

[0024] If at least one second throttle element is arranged in the section of the overlap area formed by the outlet seat, an opening of the at least one second throttle element facing the outlet seat guide may not yet be, or only partially, located in the overlap area in the venting position, so that this opening is fully or at least partially open. The other opening of the at least one second throttle element is open to the working chamber. To reach the venting position, the outlet seat is then moved further towards the outlet seat guide by the relay piston, so that the opening of the at least one second throttle element facing the outlet seat guide is increasingly, and at the latest in the venting position completely, located in the overlap area, so that this opening is closed by the outlet seat guide.The at least one second throttling element can, for example, be designed as a channel, through-hole or other shaped channel, or can be composed of a combination of at least two of the aforementioned design geometries.

[0025] If at least one second throttling element is arranged in the section of the overlap area formed by the outlet seat guide, an opening of the at least one second throttling element facing the outlet seat may, in the vented position, not yet be located, or only partially be located, in the overlap area. Starting from the vented position, the opening facing the outlet seat is then increasingly located in the overlap area until the vented position is reached, and at the latest in the vented position, it is completely located in the overlap area and is closed by the outlet seat. The other opening of the at least second throttling element is open for venting. Here, too, the at least one second throttling element can be designed, for example, as a channel, through-hole, or other shaped channel, or it can be composed of a combination of at least two of the aforementioned geometries.

[0026] In particular, the exhaust seat guide has at least two spaced-apart guide wall sections extending around the vent in the direction of movement of the exhaust seat, forming an exhaust seat chamber between them. The exhaust valve seat has a sleeve that extends in a double-walled fashion from the exhaust seat surface facing the relay piston towards the exhaust seat guide. An outer sleeve wall of the double-walled sleeve, viewed from the vent, forms a substantially fluid-tight overlap zone around the outer guide wall section with the outer guide wall section of the exhaust seat guide, at least in the at least one intermediate position of the relay piston between the vent position and the aeration position.An inner cuff wall of the double-walled cuff, viewed from the vent, forms an overlap zone around the inner guide wall section with the inner guide wall section of the outlet seat guide, at least in the at least one intermediate position of the relay piston between the vent position and the aeration position. The at least one second throttling element is arranged in a section of the overlap zone formed by the inner cuff wall and / or in a section of the overlap zone formed by the inner guide wall section.

[0027] The outlet seat guide can, for example, be designed as a double-walled hollow cylinder section, the cylinder walls of which extend as guide wall sections from the relay housing in the direction of movement of the relay piston towards the relay piston. The inner cylinder wall, as the inner guide wall section, encloses the vent. Similarly, the outlet seat can be designed as a cylindrical cover with a disc-shaped surface facing the relay piston in the direction of movement, from which the double-walled sleeve extends in a direction away from the relay piston. The sleeve is understood to be a structure surrounding the outlet seat guide in the circumferential direction.

[0028] In the double-walled design of the sleeve, the outer sleeve wall forms a substantially fluid-tight overlap with the outer guide wall section from the vented position to the aerated position. For this purpose, for example, the inner surface of the outer sleeve wall can, at least partially, fully contact the outer surface of the outer guide wall section. The corresponding overlap section of the outer sleeve wall can be designed as a sealing lip. Alternatively or additionally, a sealing element can also be arranged between the outer sleeve wall and the outer guide wall section.The term "essentially fluid-tight" is to be understood as meaning that any leaks occurring due to manufacturing are so small that, for example, no compressed air from the reservoir chamber enters the outlet seat chamber that would affect the proper intended functioning of the relay valve.

[0029] The inner sleeve wall forms an overlap area with the inner guide wall section in at least one intermediate position, and especially along the entire path from the vented position to the aerated position. The inside of the inner sleeve wall can overlap with the outside of the inner guide wall section, or vice versa. The overlapping section of the inner sleeve wall forms a sealing lip. In the case that the inside of the inner sleeve wall overlaps with the outside of the inner guide wall section, the at least one second throttling element can, for example, be designed as a pocket with an opening facing the inside of the inner sleeve wall and an opening facing an end face towards the relay piston and thus towards venting. Here, a pocket is defined as a notch or...A groove is understood to be one that is limited in the circumferential direction, here in the direction of the cylinder circumference of the inner guide wall section. In the overlap area, the inside of the inner sleeve wall then rests against the outside of the inner guide wall section, except for the area of ​​the pocket. In the vented position, the actual overlap area is smaller than the maximum overlap area in the aerated position. The pocket extends in the direction of movement of the outlet seat, so that the opening of the pocket facing the inside of the inner sleeve wall is at least partially open in the vented position and closed in the aerated position. In particular, the opening of the pocket facing the inside of the inner sleeve wall is also at least partially open in an intermediate position or range of positions.In other words, the opening cross-section of the opening of the pocket facing the inside of the inner cuff wall decreases continuously from the venting position to the ventilation position until the opening cross-section is completely closed.

[0030] In particular, the outlet seat has at least one through-hole that fluidically connects the working chamber and the outlet seat chamber. When the relay piston rests on the outlet seat, and the double-walled sleeve overlaps the corresponding guide wall sections with its respective sleeve walls, air from the working chamber can thus be introduced into the outlet seat chamber via the through-hole for possible discharge via the at least one second throttle element for venting. Alternatively or additionally, this can also be achieved through another fluidic connection from the working chamber to the outlet seat chamber.

[0031] The fluidic connection forms, in particular, a throttled flow connection.

[0032] Accordingly, the air can be introduced into the outlet seat chamber in a controlled manner according to the flow cross-section intended for throttling.

[0033] In one embodiment, the relay piston is designed as a stepped piston.

[0034] This allows different pressure equilibrium conditions to be set.

[0035] In particular, the surface of the relay piston facing the control chamber is larger as a stepped piston than the surface of the relay piston facing the working chamber.

[0036] In one embodiment, the flow cross-section provided by the at least one second throttling element is smaller than the flow cross-section provided by the first at least one throttling element.

[0037] This prevents at least one second throttling element from interfering with the function of at least one first throttling element.

[0038] In one embodiment, the control chamber is connected to the vent via at least one third throttling element when the relay piston is in the vent position. The connection between the control chamber and the vent via the at least one third throttling element is interrupted when the relay piston is in the vent position or in the intermediate position. In addition to venting the working chamber, the at least one third throttling element in the vent position also vents the control chamber to help maintain the vent position.

[0039] In particular, the flow cross-section provided by the at least one third throttling element is larger than the flow cross-section provided by the at least one first throttling element.

[0040] Accordingly, the influence of at least one first throttling element on the function of at least one third throttling element can be reduced in the venting position.

[0041] In one embodiment, the at least one third throttling element is included in or formed by at least one through-hole in a wall of the relay piston. An element fixed to the relay valve housing, designed as a relay piston seal or including a relay piston seal, is provided, which interacts with the at least one third throttling element such that, depending on the position of the relay piston within the relay valve housing, the control chamber is connected to the vent via the at least one third throttling element, or such a connection is blocked.

[0042] In particular, a flow or throttling cross-section of the at least one third throttling element can be formed by the at least one through-hole in the relay valve piston.

[0043] According to a further development, an area on this side of an end facing the control chamber of the element fixed to the relay valve housing can be connected to the control chamber, wherein a) if the at least one through-hole at least partially extends beyond the end towards the control chamber, the control chamber is connected to the vent via the at least one third throttling element, and b) if the at least one through-hole does not extend beyond the end towards the control chamber, such a connection is blocked.

[0044] In other words, the relay piston with the at least one through-bore, which forms the at least one third throttling element, acts as a slide valve in a slide valve. Depending on the position of the slide valve (relay piston) relative to the end of the element fixed to the relay valve housing facing the control chamber, a flow connection between the control chamber and the vent is either established or not. The element fixed to the relay valve housing opens or closes the at least one through-bore depending on the position of the relay valve piston. This design contributes to a cost-effective and simple implementation of the invention.

[0045] In particular, the element fixed to the relay valve housing can include at least one relay piston seal fixed to the relay piston housing, against which a jacket wall of the relay piston seals, in which at least one through-hole is then formed. Thus, the relay piston seal fulfills an advantageous dual function, namely, on the one hand, its original sealing function and, on the other hand, to represent an element of the slide valve.

[0046] In particular, through-holes forming several third throttling elements can be arranged side by side, in close proximity to each other, or, viewed in the direction of movement of the relay piston, also in series one after the other and / or side by side, and can be formed, in particular, on an outer shell wall of the relay piston. The at least one through-hole can, in particular, extend radially and / or axially with respect to the relay piston or its direction of movement.

[0047] In one embodiment, the relay piston is biased into the vented position by means of a spring.

[0048] Accordingly, the relay piston can be pre-tensioned into the venting position by means of a spring, in which the outlet seat of the double seat valve controlled by the relay piston is open and a working port of the relay valve is connected to a vent, which, for example, in a parking brake control device, is conducive to a stable assumption of the "parked" state.

[0049] In one embodiment, the outlet seat is loaded in the direction of the inlet seat by outlet seat spring means.

[0050] The preload can further assist in assuming the vented position. The exhaust seat springs can, for example, be located in the exhaust seat chamber.

[0051] According to a further aspect, the present invention relates to an electropneumatic control device for controlling at least one pneumatic device. The electropneumatic control device has a connection for the at least one pneumatic device and a solenoid valve device controllable by means of an electronic control unit. Furthermore, the electropneumatic control device has a previously described relay valve, the pneumatic control input of which is connected on one side to the solenoid valve device and on the other side to its working output and to the connection for the at least one pneumatic device, and a supply connection for at least one compressed air supply, which is connected on one side to the first solenoid valve device and on the other side to the supply input of the relay valve.

[0052] The pneumatic device could, for example, be a parking brake containing at least one spring-loaded brake cylinder or another relay valve.

[0053] Following the example of a parking brake containing at least one spring-applied brake cylinder, the electropneumatic control device in this case is a parking brake control device. The configuration and operation are illustrated in an exemplary embodiment as described below. The described structural features and functionalities also represent other applications, such as the control of another relay valve as a pneumatic device instead of the control of a parking brake containing at least one spring-applied brake cylinder. Therefore, the parking brake containing at least one spring-applied brake cylinder is synonymous with a pneumatic device, and the electropneumatic parking brake control device is synonymous with an electropneumatic control device.

[0054] The electropneumatic parking brake control device for controlling a parking brake comprising at least one spring-applied brake cylinder has a connection for the at least one spring-applied brake cylinder, a solenoid valve assembly controllable by an electronic control unit, and a previously described relay valve whose pneumatic control input is connected on one side to the solenoid valve assembly and on the other side to its working output and to the connection for the at least one spring-applied brake cylinder. Furthermore, the electropneumatic parking brake control device has a supply connection for at least one compressed air reservoir, which is connected on one side to the first solenoid valve assembly and on the other side to a supply input of the relay valve, and a feedback line through which the working output and the pneumatic control input of the relay valve are connected to each other.The relay valve has a control chamber connected to the pneumatic control input, at least one relay piston controlled by the pressure in the control chamber and actuating a double-seat valve, and a working chamber connected to the working output, wherein the relay piston is guided within a relay valve housing and delimits the control chamber and the working chamber, and the double-seat valve comprises at least one inlet seat and at least one outlet seat, wherein the working chamber is connected to a vent when the outlet seat is open and to the supply inlet when the inlet seat is open, and wherein at least one first throttling element is arranged in the feedback line, such that the working output and the pneumatic control input of the relay valve are always in throttled flow communication with each other.

[0055] The working chamber of the relay valve is connected to the vent via at least a second throttling element, exclusively when the relay piston is in a venting position or an intermediate position, but the connection of the working chamber to the vent via the at least one second throttling element is interrupted when the relay piston is in a venting position, the venting position of the relay piston within the relay valve housing being characterized in that the outlet seat is fully open and the inlet seat of the double-seat valve is fully closed, and thus a pressure is present at the connection for the at least one spring-applied brake cylinder, which corresponds to a clamping pressure of the at least one spring-applied brake cylinder in which it is fully clamped.and wherein the ventilation position of the relay piston within the relay valve housing is characterized in that the inlet seat is fully open and the outlet seat is fully closed, and thereby a pressure is present at the connection for the at least one spring-applied brake cylinder which corresponds to a release pressure of the at least one spring-applied brake cylinder in which it is fully released, and wherein an intermediate position of the relay piston within the relay valve housing is characterized in that a pressure is present at the connection for the at least one spring-applied brake cylinder which is greater than the clamping pressure but less than the release pressure.

[0056] In one embodiment, it is provided that the control chamber of the relay valve is connected to the vent via at least one third throttling element, and only when the relay piston is in the vent position, wherein the connection between the control chamber and the vent via the at least one third throttling element is interrupted when the relay piston is in the vent position or in the intermediate position, and wherein the flow cross-section provided by the at least one third throttling element is larger than the flow cross-section provided by the at least one first throttling element, and the flow cross-section provided by the at least one second throttling element is smaller than the flow cross-section provided by the at least one first throttling element.

[0057] In the event of a power failure, without at least one second throttling element in the control chamber of the relay valve and in the spring-applied brakes, the same pressure can be established, preventing compensating flows through the feedback line via the first throttling element. The instantaneous pressure in the spring-applied brakes is then maintained, so that neither the "driving" nor the "parking" state can be reliably assumed. The relay valve piston is then in an intermediate position as described above.

[0058] With at least one second throttling element, it is now ensured, with regard to the case described above, that in the event of a power failure during the execution of an emergency or auxiliary braking function, the "Park" state can always be stably assumed. With at least one second throttling element, it is now ensured that in the event of a power failure during the execution of an emergency or auxiliary braking function, the pressure in the working chamber of the relay valve drops, which in turn also reduces the brake pressure in the spring-applied brakes and consequently the "Park" state is stably assumed.

[0059] This demonstrates a method that can be implemented with minimal effort to ensure that, in the event of a power failure during the execution of the emergency or auxiliary braking function and the resulting uncertain state of the parking brake, the vehicle always assumes and / or stably maintains the "parking" state. Throttle elements are simple components that, in particular, do not require electrical control and are therefore fail-safe.

[0060] For a person skilled in the art, it is readily possible to design at least one first throttling element, at least one second throttling element, and optionally further throttling elements, such as at least one third throttling element, in such a way that the respective functionalities described are achieved.

[0061] In particular, the electronic control unit can be connected to an electrical parking brake signal connection for an electrical parking brake signal transmitter, via which parking brake signals can be controlled into the electronic control unit.

[0062] The electronic control unit can also be connected to a signal input for receiving signals from which it generates parking brake signals. Signals can then preferably be fed into this signal input, for example via a vehicle data bus, or into the parking brake signal input of the parking brake control unit, from which the control unit itself generates parking brake signals. These signals can be, in particular, signals that detect a standstill of the vehicle as part of a driver assistance system such as a hill start assist system. For example, when the vehicle is detected as stationary, the electronic control unit generates a parking brake signal to apply the parking brake based on these signals, which are then vehicle standstill signals.Alternatively, signals fed into the parking brake control unit, from which the electronic control unit of the parking brake control unit then generates parking brake signals, could originate from any other driver assistance systems, such as an ACC (Adaptive Cruise Control) system in the event that the parking brake is used as an auxiliary brake while driving. In all these cases, the parking brake signals are therefore not dependent on the activation of the parking brake signal transmitter, but are generated automatically by one or more driver assistance systems.

[0063] Of course, the signals fed into the parking brake control unit, from which the electronic control unit of the parking brake control unit then generates parking brake signals, can originate from an actuating device that can be manually operated by the driver, with which, depending on the degree of actuation of an actuating element, at least the states "Park" and "Drive" are established and, in particular, the level of the applied parking brake force within the framework of the emergency or auxiliary braking function.

[0064] For this purpose, this signal connection, or the parking brake signal connection, is designed, for example, to be connectable to a vehicle data bus in order to feed signals transmitted via the vehicle data bus into the electronic control unit, which then generates parking brake signals depending on these signals. The communication between the electronic control unit and the vehicle data bus is preferably bidirectional. In one embodiment, the solenoid valve assembly is formed by at least two 2 / 2-way solenoid valves, each with a closed position and a free position. A first 2 / 2-way solenoid valve is connected as an inlet valve between the control input of the relay valve and the supply connection, and a second 2 / 2-way solenoid valve is connected between the control input of the relay valve and a pressure sink.

[0065] In particular, the first 2 / 2-way solenoid valve and the second 2 / 2-way solenoid valve each have a de-energized, preferably spring-loaded, closed position and an energized open position.

[0066] In the event of a failure of the electrical power supply, the control input of the relay valve can be disconnected from both the supply connection and the vent or pressure sink, so that no control compressed air can reach the relay valve from the supply connection or escape from it via the pressure sink.

[0067] Alternatively, the solenoid valve assembly can also include at least one 3 / 2 solenoid valve.

[0068] Overall, this results in advantages in terms of a simple and cost-effective design, a small installation space requirement and a robust, proven technology, as it allows the use of modular components such as 2 / 2 solenoid valves and / or 3 / 2 solenoid valves as well as relay valves.

[0069] According to a further development, it can be provided that when a parking brake signal representing a "driving" state is applied to or generated in the electronic control unit, the second 2 / 2-way solenoid valve is controlled in the closed position and the first 2 / 2-way solenoid valve is initially controlled in the open position. For example, by energizing the first 2 / 2-way solenoid valve, it is therefore controlled for a certain period of time.

[0070] The first 2 / 2-way solenoid valve is initially switched to the open position, while the second 2 / 2-way solenoid valve remains in the closed position. After the specified time required for the pressure at the connection for at least one spring brake cylinder to reach the full release pressure of the spring brake cylinder, the first 2 / 2-way solenoid valve is then switched to the closed position. Thus, the control input is only connected to the working output in a throttled manner. Any slight leakage to a pressure sink, which might occur, for example, due to a defect, would be compensated for via the inlet seat of the relay valve.

[0071] When a parking brake signal representing the state "apply parking brake with a specific brake pressure value" is input to or generated by the electronic control unit, the electronic control unit preferably controls the first 2 / 2-way solenoid valve and / or the second 2 / 2-way solenoid valve, depending on the respective brake pressure value, in the closed or open position. This is particularly relevant during auxiliary or emergency braking, where the parking brake must replace or assist the service brake.

[0072] For example, to increase the pressure at the connection for the at least one spring-applied brake cylinder, the first 2 / 2-way solenoid valve is controlled in the open position, so that the pressure at the control input of the relay valve and thus also at the connection for the at least one spring-applied brake cylinder is increased.

[0073] For example, to reduce the pressure at the connection for the at least one spring-applied brake cylinder, the second 2 / 2-way solenoid valve is switched to the open position, so that the pressure at the control input of the relay valve and thus also at the connection for the at least one spring-applied brake cylinder is reduced.

[0074] In the first case, the electronic control unit can control the first 2 / 2-way solenoid valve and in the second case the second 2 / 2-way solenoid valve alternately or pulsedly in the closed position and for a longer period in the open position in order to achieve a ramp-shaped or gradual pressure increase or decrease, which is particularly advantageous for sensitive metering or control of the parking brake force or parking brake pressure, especially in the context of an auxiliary or emergency brake application.

[0075] The airflow through the at least one first throttling element, which may occur depending on the current pressure difference between the working output and control input of the relay valve, as well as any slight leakage to a pressure sink or to the supply pressure that may occur, e.g. due to a defect, can be compensated by briefly energizing the opposing 2 / 2 solenoid valve.

[0076] According to further training, when a parking brake signal representing the "parking" state is applied or generated, the electronic control unit can control the first 2 / 2-way solenoid valve to the closed position and the second 2 / 2-way solenoid valve first to the open position and then to the closed position. For example, by applying power, the second 2 / 2-way solenoid valve is initially switched to the open position for a specific period, while the first 2 / 2-way solenoid valve remains in the closed position. After the specified time has elapsed, which is necessary for the pressure at the connection for at least one spring-applied brake cylinder to drop sufficiently so that the relay valve remains in the venting position even after the second 2 / 2-way solenoid valve is switched off, the second 2 / 2-way solenoid valve is then controlled to the closed position.Thus, the control input is only connected to the working output in a throttled manner. Any slight leakage to the supply pressure that might occur, for example due to a defect, would be vented via the outlet seat of the relay valve.

[0077] The electromagnetic parking brake control device is particularly preferred for use in a towing vehicle-trailer combination and then has at least one connection for a trailer control valve, which can be connected to the connection for at least one spring-applied brake cylinder.

[0078] Furthermore, at least one pressure sensor can be connected to the connection for the at least one spring brake cylinder and / or at least one pressure sensor to the control input of the relay valve and / or at least one pressure sensor to the connection for the trailer control valve, which feeds a signal representing an actual pressure into the electronic control unit.

[0079] The electronic control device can then be designed to perform a target-actual comparison within the framework of pressure control, based on a signal representing an actual pressure and a signal representing a value for a target pressure, and / or to perform a pressure plausibility check and / or to determine the supply pressure present at the supply connection.

[0080] If, for example, a pressure sensor is connected to the working output of the relay valve and thus also connectable to the connection for the at least one spring brake cylinder or to the connection for the trailer control valve, the actual pressure and, from this, the operating state of the at least one spring brake cylinder (released, engaged, or partially released or engaged) can be determined. The same applies to the operating state of the trailer brakes, which can be determined from the actual pressure at the connection for the trailer control valve. Furthermore, a pressure control loop is implemented in which the first solenoid valve assembly, in conjunction with the relay valve, forms the actuators.

[0081] If a pressure sensor is connected to the control input of the relay valve, the actual pressure regulated by the solenoid valve assembly, in particular by the first and second 2 / 2-way solenoid valves, can be determined very quickly, enabling a highly dynamic pressure control loop. Furthermore, the operating state of at least one spring-applied brake cylinder (released, engaged, or partially released or engaged) and the actual brake pressure there can also be approximately determined, taking into account the transmission characteristics of the relay valve. The same applies to the operating state of the trailer brakes.

[0082] If a first pressure sensor is connected to the control input and a second pressure sensor to the working output of the relay valve, this enables fault detection via plausibility checks. For example, the actual pressure values ​​of the first and second pressure sensors must be in a specific relationship to each other, taking certain tolerances into account, depending on the operating state. Fault detection or monitoring is thus fast, complete, and can be performed in multiple operating states. Furthermore, faster pressure control is possible than if only one pressure sensor is located at the working output of the relay valve or one pressure sensor at the control input of the relay valve.

[0083] If, in addition to a pressure sensor at the working output and / or control input of the relay valve, another pressure sensor is connected to the trailer control valve, a direct measurement of the supply pressure at the supply connection is possible in several operating states without having to set the operating state to "Driving". Furthermore, rapid fault detection via plausibility checks is also possible. For example, the actual pressures of the pressure sensors must show the same values ​​when the solenoid valves are switched in such a way that a pressure connection is established between the pressure sensors. As before, determining the supply pressure is also possible in several operating states.Advantageously, this also makes it possible to regulate the pressure at the connection for the trailer control valve when the "stretch brake" state is provided, in which only the trailer brakes, but not the towing vehicle brakes, are applied in a metered manner to stretch the towing vehicle-trailer combination.

[0084] According to a further development, at least the relay valve, the solenoid valve assembly, the electronic control unit, the at least one first throttle element, the at least one second throttle element, the optional at least one third throttle element, as well as the reservoir connection, the connection for the at least one spring-applied brake cylinder, and the parking brake signal connection can be integrated into a single unit. This results in a compact unit that can be further expanded as a basic module.

[0085] The features described in the description of the corresponding relay valve are equally applicable to the electropneumatic control unit. Likewise, features described for the electropneumatic control unit are transferable to the relay valve, provided they have not already been described for the relay valve.

[0086] According to a further aspect, the present invention relates to a braking system of a vehicle comprising a previously described electropneumatic control device, wherein the pneumatic device to be controlled is a parking brake comprising at least one brake cylinder.

[0087] The braking system includes, in particular, an electronically controlled parking brake (EPB).

[0088] The features described in the description of the electropneumatic control unit and / or the corresponding relay valve are equally applicable to the brake system. Likewise, features described for the brake system relating to the electropneumatic control unit are transferable to the electropneumatic control unit and / or the corresponding relay valve, provided they have not already been described for the electropneumatic control unit and / or the relay valve.

[0089] An exemplary embodiment of the present invention is described below with the aid of the accompanying drawings.

[0090] In detail, it shows

[0091] Fig. 1 a schematic circuit diagram of an exemplary embodiment of an electropneumatic parking brake control device as an electropneumatic control device with an exemplary embodiment of a relay in cross-sectional view in a venting position according to a position ‘Park’ or ‘Parking brake’;

[0092] Fig. 2 shows the schematic circuit diagram according to Fig. 1 with the relay in

[0093] Cross-sectional view in an intermediate position according to a position "apply parking brake with a specific brake pressure value" within the context of an emergency or auxiliary brake function;

[0094] Fig. 3 shows the schematic circuit diagram according to Fig. 1 with the relay in cross-sectional view in a ventilation position according to a "driving" position;

[0095] Fig. 4 shows a top view of a cross-sectional representation in an overlap area of ​​an outlet seat with an outlet seat guide with a second throttling element according to a first exemplary embodiment of Fig. 1;

[0096] Fig. 5 shows a side view of a cross-sectional representation of an overlap area of ​​an outlet seat with an outlet seat guide with a second throttling element according to a second exemplary embodiment;

[0097] Fig. 6 shows a side view of a cross-sectional representation of an overlap area of ​​an outlet seat with an outlet seat guide with a second throttling element according to a third exemplary embodiment;

[0098] Fig. 7 shows a top view of a cross-sectional representation of an overlap area of ​​an outlet seat with an outlet seat guide with a second throttling element according to a fourth exemplary embodiment;

[0099] Fig. 8 shows a side view of a cross-sectional representation of an overlap area of ​​an exhaust seat with an exhaust seat guide with a second throttling element according to a fifth exemplary embodiment; and

[0100] Fig. 9 shows a side view of a cross-sectional representation of an overlap area of ​​an outlet seat with an outlet seat guide with a second throttling element according to a sixth exemplary embodiment.

[0101] The following description of exemplary embodiments based on the accompanying drawings refers in particular in Figures 1 to 3 to an electropneumatic parking brake control device as an electropneumatic control device, whereby embodiments of the relay valve itself are also included.

[0102] Fig. 1 shows a schematic circuit diagram of an exemplary embodiment of an electropneumatic parking brake control device 1 as an electropneumatic control device with an exemplary embodiment of a relay 18 in cross-sectional view in a venting position according to a position ‘Parking’ or ‘Parking brakes’.

[0103] The electropneumatic parking brake control device 1 preferably represents a control device of an electropneumatic parking brake device of a towing vehicle-trailer combination and is in this case arranged on the towing vehicle by way of example.

[0104] The electro-pneumatic parking brake control device 1 has a supply port 2, which is protected by a check valve 4. A supply line 6 extends from the supply port 2 to a first solenoid valve assembly 8 with a first 2 / 2-way solenoid valve 10 as the inlet valve and a second 2 / 2-way solenoid valve 12 as the outlet valve. The first 2 / 2-way solenoid valve 10, like the second 2 / 2-way solenoid valve 12, is in the closed position shown when de-energized, while both valves 10 and 12 switch to the open position when energized and are controlled by an electronic control unit 14.

[0105] Furthermore, a supply inlet 16 of a relay valve is also connected to the supply port 2 via the supply line 6. A pneumatic control inlet 20 of the relay valve 18 is connected via a control line 22 to the combination of inlet valve 10 (first 2 / 2-way solenoid valve) and outlet valve 12 (second 2 / 2-way solenoid valve).

[0106] Specifically, in the de-energized closed position of the second 2 / 2-way solenoid valve 12, the connection between the control line 22 or the control input 20 of the relay valve 18 and a pressure sink 24 is interrupted, while this connection is open in the energized open position. Similarly, in the de-energized closed position of the first 2 / 2-way solenoid valve 10, the connection between the control line 22 or the control input 20 of the relay valve 18 and the supply port 2 is interrupted, while this connection is open in the energized open position.

[0107] Furthermore, a first throttling element 30 is connected in a feedback line 26 between a working output 28 of the relay valve 18 and the control input 20 of the relay valve 18, through which the flow cross-section of the feedback line 26 is narrowed and the air mass flow between the working output and the pneumatic control input of the relay valve is limited or throttled by means of the narrowing of the flow cross-section.

[0108] In the present embodiment, the two 2 / 2-way solenoid valves 10, 12 are spring-loaded to their de-energized position and are switched by energizing them via the control device 1.

[0109] The working output 28 of the relay valve 18 is connected via a working line 38 to a connection 40 for at least one spring-applied brake cylinder. Preferably, two spring-applied brake cylinders (not shown here) on the rear axle are connected to this connection 40.

[0110] Depending on the switching position of the first 2 / 2-way solenoid valve 10 and the second 2 / 2-way solenoid valve 12 (inlet-outlet solenoid valve combination), the control line 22 or the control input 20 of the relay valve 18 is vented or aerated, so that venting or aeration by increasing the air volume by means of the relay valve 18 results in a corresponding venting or aeration of the working output 28 and thus of the connection 40 for the at least one spring-applied brake cylinder.

[0111] The relay valve 18 is initially constructed in a largely known manner and comprises a control chamber 42 connected to the control line via the control input 20, a relay piston 46 movable within a housing 44 and delimiting the control chamber 42, and a valve body 48 formed on the relay piston 46 or on its relay valve piston rod. The valve body 48, together with an outlet seat 50 movably mounted in the housing 44 and a sleeve 52, forms an outlet valve of a double-seat valve. Furthermore, the relay valve 18 includes an inlet seat 54 formed on the housing 44, against which the outlet seat 50 is biased, forming an inlet valve of the double-seat valve. The outlet seat 50 also has a central through-bore which, when the relay piston 46 is lifted from the outlet seat 50, connects a vent 56 to a working chamber 58, which is connected to the working outlet 28 for venting purposes.On the other hand, a reservoir chamber 60 connected to the reservoir inlet 16 is connected to the working chamber 58 when the outlet seat 50 is lifted from the inlet seat 54, in order to vent the working outlet 28. The position of the relay piston 46, which with its valve body 48 can push the outlet seat 50 downwards to lift it from the inlet seat 54, is therefore determined by the pressure at the control inlet 20 or in the control chamber 42. Finally, the outlet seat 50 is pressed against the inlet seat 54 by means of an outlet seat spring 62. In addition, a relay piston spring 64 with the force FF pushes the relay piston 46 away from the outlet seat 50 towards the control chamber 42.

[0112] The switching states of the two 2 / 2-way solenoid valves 10, 12 are determined by the control unit 14, in particular depending on the parking brake signals present at the parking brake signal terminal 32. For this purpose, the parking brake signal generator 36 is designed to trigger parking brake signals depending on their actuation, which represent the operating states described below.

[0113] The control unit can be connected via the parking brake signal connection or via another signal connection to a vehicle data bus (not shown in the figures), via which digital data can be received from and sent to other control units. Instead of or in addition to the parking brake signal transmitter 36, which is manually operated by the driver, parking brake signals can also be fed into the control unit 14 from another control unit, for example, via a vehicle data bus, such as a driver assistance system like a hill start assist system. Parking brake signals can then be generated by the control unit 14 itself based on signals received via such a vehicle data bus.For example, the parking brake can be automatically engaged when the vehicle has come to a standstill, or automatically released when it is detected that the vehicle is about to move.

[0114] Against this background, the operation of the electromagnetic parking brake control device 1 is as follows:

[0115] In the basic state of the electropneumatic parking brake control device 1 shown in Fig. 1, both the first 2 / 2-way solenoid valve 10 and the second 2 / 2-way solenoid valve 12 are de-energized, so that the control input 20 is always connected to the working output 28 of the relay valve 18 via the first throttle element 30. This ensures stable feedback and prevents compressed air from flowing from the supply port 2 to the control input 20 of the relay valve 18 or from escaping from it to the pressure sink 24. This also keeps the pressure at port 40 for the at least one spring-applied brake cylinder, and consequently its engaged and disengaged positions, constant.

[0116] If, upon receiving a corresponding parking brake signal, the pressure at connection 40 for at least one spring-applied brake cylinder is to be increased, for example in the operating state "apply parking brake with a specific brake pressure value" as part of an emergency or auxiliary brake function, the first 2 / 2-way solenoid valve 10 is energized, switching it to the open position and thereby increasing the pressure in the control chamber 42 of the relay valve 18. This is achieved in particular by pulsing the first 2 / 2-way solenoid valve 10.

[0117] Then the relay piston 46 moves downwards, opens the inlet seat 54 of the double-seat valve, and allows supply pressure to flow into the working chamber 58. Afterwards, the relay piston 46 moves back to a neutral position in which the inlet seat 54 and outlet seat 50 of the double-seat valve are closed. However, if, in the operating state "actuate parking brake with a specific brake pressure value" within the framework of the emergency or auxiliary braking function, a lower pressure is to be regulated at the connection 40 for the at least one spring-applied brake cylinder in response to a corresponding parking brake signal, the control pressure in the control chamber 42 is preferably reduced by pulsing the second 2 / 2-way solenoid valve 12.

[0118] Then the relay piston 46 moves towards the control chamber 42 and vents the working chamber 58 via the outlet seat 50 of the double seat valve until force equilibrium is restored, whereupon the relay piston 46 returns to its neutral position.

[0119] Since the pressures in the control chamber 42 and the working chamber 58 are generally not the same during the pressure control or pressure regulation described above, and a certain amount of air always flows towards the lower pressure via the first throttling element 30, the resulting proportion of the pressure change in the control chamber 42 is preferably compensated for by appropriate pulsed control of the first 2 / 2-way solenoid valve 10 or the second 2 / 2-way solenoid valve 12. This applies to pressure increases, pressure decreases, and pressure maintenance, unless the required pressure at the port 40 for the at least one spring-applied brake cylinder is exactly the same as the supply pressure or atmospheric pressure.

[0120] To establish the "Driving" operating state in response to a corresponding parking brake signal, the first 2 / 2-way solenoid valve 10 is energized for an extended period. This vents the control chamber 42, although initially a small portion of the air directed from the first 2 / 2-way solenoid valve 10 to the control chamber flows through the throttle element 30 into the working chamber. The pressure in the working chamber 58 then rises faster than in the control chamber 42 until it finally exceeds the control chamber. Air then flows from the working chamber 58 into the control chamber 42 via the feedback line 26 and the first throttle element 30, thus reinforcing the process. This forces the relay piston 46 stably into its lower end position, pointing towards the working chamber 58, so that it permanently opens the inlet seat 54 of the double-seat valve and connects the working chamber 58 to the supply port 2.

[0121] Since the control chamber 42 is now permanently supplied with storage pressure via the first throttle element 30, the working chamber 58 and the inlet seat 54, the first 2 / 2-way solenoid valve 10 can also be depressurized to switch it into its closed position.

[0122] To establish the "park" operating state, the second 2 / 2-way solenoid valve 12 is energized for a certain period of time. This vents the control chamber 42 until atmospheric pressure is reached. Then the relay piston 46 moves towards the control chamber 42 and vents the working chamber 58 via the outlet seat 50 of the double-seat valve.

[0123] The relay piston spring 64, which compresses the relay piston 46, ensures that it moves to its upper end position and remains there, thus keeping the outlet seat 50 permanently fully open. Since the control chamber 42 is now permanently connected to the atmosphere via the throttle element 30, the working chamber 58, and the open outlet seat 50, the second 2 / 2-way solenoid valve 12 can be vented and thus moved into its closed position.

[0124] To ensure that the "Park" state is reliably reached in the event of a power failure during the execution of an emergency or auxiliary braking function, a second throttling element 65 is provided. This ensures that, in the event of a power failure during the execution of the emergency or auxiliary braking function, the pressure in the working chamber 58 of the relay valve 18 drops, which in turn reduces the brake pressure in the spring-applied brakes and consequently allows the "Park" state to be reliably reached.

[0125] In the present embodiment, the outlet seat 50 is designed as a cylindrical cover with a disc-shaped or annular surface facing the relay piston 46 in the direction of movement. The double-walled sleeve 52 extends from this surface in a direction away from the relay piston 46. The outlet seat 50 is guided from the vented position to the vented position by an outlet seat guide 45 in the direction of movement of the relay piston 46. The outlet seat guide 45 is designed as a double-walled hollow cylinder section, the cylinder walls of which extend as guide wall sections from the relay housing 44 in the direction of movement of the relay piston 46 towards the relay piston 46. The inner cylinder wall, as the inner guide wall section, encloses the vent 56.

[0126] In the double-walled design of the sleeve 52, with respect to the double-walled hollow cylinder section of the outlet seat guide 45, the outer sleeve wall forms the essentially fluid-tight overlap area with the outer guide wall section from the vented position to the aerated position. For this purpose, for example, an inner surface of the outer sleeve wall can, at least partially, fully abut the outer surface of the outer guide wall section. The corresponding overlap section of the outer sleeve wall is designed here as a sealing lip.

[0127] The inner sleeve wall forms an overlap area with the inner guide wall section along the entire path from the vented position to the aerated position. The inner surface of the inner sleeve wall overlaps with the outer surface of the inner guide wall section. This overlapping section of the inner sleeve wall forms a sealing lip. In the present embodiment, the at least one second throttling element 65 is designed as a pocket with an opening facing the inner surface of the inner sleeve wall and an opening facing an end face towards the relay piston 46, and thus towards the vent 58 or the fluid connection with the vent 58. Here, a pocket is understood to be a cut or groove that is limited in the circumferential direction, in this case, in the direction of the cylinder circumference of the inner guide wall section.In the overlap area, the inner surface of the inner cuff wall rests against the outer surface of the inner guide wall section, except for the area of ​​the pocket. In the vented position, the actual overlap area is smaller than the maximum overlap area in the aerated position. The pocket extends in the direction of movement of the outlet seat 50, such that the opening of the pocket facing the inner surface of the inner cuff wall is at least partially open in the vented position and closed in the aerated position. In particular, the opening of the pocket facing the inner surface of the inner cuff wall is also at least partially open in an intermediate position. In other words, the cross-sectional area of ​​the opening of the pocket facing the inner surface of the inner cuff wall decreases continuously from the vented position to the aerated position until the opening is completely closed.

[0128] Fig. 4 shows, for the embodiment of the second throttle element 65 as a pocket, a top view of a cross-sectional view perpendicular to the direction of movement of the outlet seat 50 in an overlap area of ​​the outlet seat 50 with the outlet seat guide 45 according to Fig. 1. Specifically, Fig. 4 shows the top view of the cross-sectional view of the inner guide wall section of the outlet seat guide 45 and the inner sleeve wall of the sleeve 52, which here forms a sealing section 51 in the overlap area. The inside of the inner sleeve wall, or the sealing section 51, covers the opening facing the inside of the inner sleeve wall.

[0129] The guide wall section, a pocket inserted as a second throttling element 65, extends at a specific height, i.e., along a direction of movement of the outlet seat 50. In the venting position and in an intermediate position, an open section of the opening facing the inside of the inner cuff wall remains. In the ventilation position, the opening facing the inside of the inner cuff wall is then completely covered by the sealing section 51.

[0130] Although only one second throttle element 65 is shown in the present embodiment, several second throttle valves may also be provided in alternative embodiments.

[0131] The outlet seat 50, together with the outlet seat guide 45, forms a

[0132] Outlet seat chamber 57. To transfer the pressure from the working chamber 58 into the

[0133] In order to be able to direct the exhaust seat chamber 57 to the vent 56 via the second throttle element 65, the exhaust seat 50 has a through-opening 53 which fluidically connects the working chamber 58 with the exhaust seat chamber 57.

[0134] To prevent the applied parking brake from unintentionally releasing in the event of leaks to a pressurized area, a third throttling element 66 is provided. In the present embodiment, this third throttling element 66 is formed by several radial through-holes distributed around the circumference of an outer shell wall 68 of the relay piston 46. The sum of the diameters of these through-holes constitutes the flow or throttling cross-section of the third throttling element 66. Instead of several small through-holes 66, a single larger through-hole in the shell wall 68 may also be provided. The opening of the third throttling element 66 facing away from the control chamber 43 is in fluid communication with the vent 56 (not shown).This fluid connection can be realized through a through-hole in the relay housing 44 and / or in the relay piston 46 and / or a corresponding line connection.

[0135] Furthermore, an element 67 fixed to the relay valve housing 44 is provided, which interacts with the third throttle element 66 in such a way that, depending on the position of the relay piston 46 inside the relay valve housing 44, the control chamber 42 is connected to the vent 56 via the third throttle element 66 or such a connection is blocked.

[0136] In particular, the element fixed to the relay valve housing 44 is formed here by a relay piston seal 67, against which the outer wall 68 of the relay piston 46 seals.

[0137] As shown in Fig. 1, in the vented position of the relay piston 46 in the "Park" state, the second throttle element 65 for the fluidic connection of the working chamber 58 with the vent 56 and the third throttle element 66 for the fluidic connection of the control chamber with the vent 56 are open. In the vented position of the relay piston 46, the outlet seat 50 is fully open and the inlet seat 54 is fully closed. This results in a pressure at the connection 40 for the at least one spring-applied brake cylinder, which corresponds to the clamping pressure of the at least one spring-applied brake cylinder when it is fully clamped.

[0138] Fig. 2 shows the schematic circuit diagram according to Fig. 1 with relay 18 in cross-sectional view in an intermediate position corresponding to the "actuate parking brake with a specific brake pressure value" position within the context of an emergency or auxiliary brake function. In this case, either to increase the parking brake force, the outlet seat 50 is partially opened and the inlet seat 54 is fully closed, or to reduce the parking brake force, the outlet seat 50 is fully closed and the inlet seat 54 is partially opened. After a certain time, due to the force equilibrium that then develops on the relay piston 46, both the outlet seat 50 and the inlet seat 54 are closed. According to the intermediate position of the relay piston 46 shown, a pressure is present at the connection 40 for the at least one spring-applied brake cylinder, which is greater than the clamping pressure but less than the release pressure.

[0139] In the intermediate position, the second throttle element 65 remains open, albeit with a smaller opening cross-section, and the third throttle element 66 is separated from the control chamber 42 by the relay piston seal 67.

[0140] Furthermore, the flow cross-section provided by the second throttle element 65 is smaller than the flow cross-section provided by the first throttle element 30. Consequently, during an emergency or auxiliary braking maneuver in the event of a power failure, in which the last electrically set brake pressure would normally remain in effect, the brake pressure can drop to the actuation pressure of the spring-applied brake, thus ensuring that the "Park" state is maintained even during a power failure during an emergency or auxiliary braking maneuver.

[0141] Fig. 3 shows the schematic circuit diagram according to Fig. 1 with relay 18 in cross-sectional view in a vented position corresponding to a "driving" position. In the vented position of the relay piston 46 shown, the "driving" state is assumed, and the relay piston is moved downwards to (fully) open the inlet seat 54 and (fully) close the outlet seat 50, so that the pocket forming the second throttle element 65, or the opening of the second throttle element 65 facing the inside of the inner sleeve wall, is covered or closed by the inside of the inner sleeve wall. The flow connection between the working chamber 58 and the vent 56 via the second throttle element is thus blocked.

[0142] Consequently, a flow connection between the working chamber 58 and the vent 56 through the second throttle element is only possible in the "Parking" state and in the "Activate parking brake with a specific brake pressure value" state, but not in the "Driving" state.

[0143] In the ventilation position of the relay piston 46 (“driving”) shown in Fig. 3, the inlet seat 54 is fully open and the outlet seat 50 is fully closed, and as a result, a pressure is present at the connection 40 for the at least one spring-applied brake cylinder, which corresponds to a release pressure of the at least one spring-applied brake cylinder in which it is fully released.

[0144] As already mentioned, a flow connection between the control chamber 42 and the vent 56 via the third throttle element 66 only occurs in the vent position of the relay piston 46, which corresponds to the "Park" state according to Fig. 1.

[0145] Since the flow cross-section provided by the third throttle element 66 is larger than the flow cross-section provided by the first throttle element 30, an unintentional release of the applied parking brake in the "Park" state, i.e. in the venting position of the relay piston 46, can be avoided in the event of leaks, for example, of the inlet valve (first 2 / 2-way solenoid valve) 10.

[0146] However, because the third throttling element 66, in the form of the through-holes 66, is only not covered and thus closed by the relay piston seal 67 in the venting position of the relay piston 46 and therefore in the "Park" state, but is in the emergency and auxiliary braking situation and in the "Driving" state, a flow connection between the control chamber 42 and the vent 56 via the third throttling element 66 is only possible in the "Park" state, but not in the emergency and auxiliary braking situation (Fig. 2) and in the "Driving" state (Fig. 3).

[0147] The relay piston 46, with the third throttling element 66 as a through-hole in its casing wall 68, therefore forms a slide of a slide valve, whereby a flow connection between the control chamber 42 and the vent 56 is or is not established depending on the position of the relay piston 46 relative to the end of the relay piston seal 67. The end of the relay piston seal 67, which is fixed to the relay valve housing 44, opens or closes the third throttling element 66 depending on the position of the relay valve piston 46.

[0148] If the electropneumatic parking brake control device 1 is used to control a trailer control valve, it can be designed so that the pressure at connection 40 for the at least one spring brake cylinder is simultaneously directed to a connection for a trailer control valve.

[0149] According to the present embodiment, the electronic control device 14 is configured to perform a target-actual comparison within the framework of pressure control and / or a pressure plausibility check and / or a determination of the supply pressure present at the supply connection 2, based on a signal representing an actual pressure and a parking brake signal representing a value for a target pressure.

[0150] If, for example, a pressure sensor 88 is connected to the working output 28 of the relay valve 18 and thus also connectable to the connection 40 for the at least one spring brake cylinder or to the connection for the trailer control valve, the actual pressure and, from this, the operating state of the at least one spring brake cylinder (released, applied, or partially released or applied) can be determined. The same applies to the operating state of the trailer brakes, which can be determined from the actual pressure at the connection for the trailer control valve. Furthermore, a pressure control loop can then be implemented in which the solenoid valve assembly 8, in conjunction with the relay valve 18, forms the actuators. However, if only the pressure sensor 88 is used, the pressure regulator only detects pressure deviations once a deviation in the working output pressure of the relay valve 18 has already occurred.This can lead to increased compressed air consumption.

[0151] If a pressure sensor 89 is connected to the control input 20 of the relay valve, the actual pressure regulated by the first and second 2 / 2-way solenoid valves 10, 12 can be determined very quickly, resulting in high dynamics of the pressure control loop. Furthermore, the operating state of at least one spring-applied brake cylinder (released, engaged, or partially released or engaged) and the actual brake pressure there can also be determined, although with lower accuracy compared to using the pressure sensor 88, since the response behavior and hysteresis of the relay valve 18 introduce errors. The same applies to the operating state of the trailer brakes. A particular advantage of using the pressure sensor 89 is that the pressure regulator can compensate for pressure deviations in the control chamber 42 so precisely that they do not yet lead to a pressure deviation at the working output of the relay valve.

[0152] If a first pressure sensor 88 is connected to the working output 28 and a second pressure sensor 89 to the control input of the relay valve 18, this also enables fault detection via plausibility checks. For example, the actual pressure values ​​of the first and second pressure sensors 88, 89 must be in a specific relationship to each other, taking into account certain tolerances, depending on the operating state. Fault detection or monitoring is thus fast, complete, and can be performed in multiple operating states. Furthermore, this results in faster pressure control with lower compressed air consumption than if only one pressure sensor 88 were connected to the working output 28 of the relay valve 18, and more precise pressure control of the working output pressure than if only one pressure sensor 89 were connected to the control input 20 of the relay valve 18.According to one embodiment, the relay valve 18, the first solenoid valve assembly 8 (first and second 2 / 2-way solenoid valves 10, 12), the check valve 4, the first throttle element 30, the electronic control unit 14, as well as the reservoir connection 2, the connection 40 for the at least one spring-applied brake cylinder, and the parking brake signal connection 32 can be formed in a single unit, which here represents an expandable basic module. At least one pressure sensor 88 and / or 89 can also be integrated into the basic module or the assembly 92. Furthermore, the electrical and pneumatic lines connecting the aforementioned components are also integrated into the assembly. The assembly or the basic module can have a single housing or consist of several housings or housing parts that are detachably or permanently connected to one another.

[0153] It should also be mentioned that combining the electro-pneumatic parking brake control unit with another electronically controlled vehicle system into a single unit can be advantageous, as a common electronic control unit can be used. In particular, combining it with an air preparation system offers advantages, since the supply line to the electro-pneumatic parking brake control unit can then be eliminated.

[0154] Fig. 5 shows a side view of a cross-sectional representation of an overlap area of ​​the outlet seat 50 with an outlet seat guide 45 and a second throttling element 65' according to a second exemplary embodiment. The cross-sectional representation relates to the inner sleeve wall and the inner guide wall section.

[0155] In the second embodiment, the second throttling element 65' is designed as a through-hole in the inner guide wall section, which here runs perpendicular to the inner guide wall section. In alternative embodiments, however, the through-hole can also run at a different angle and / or not be straight. In the venting position, the opening of the through-hole facing the inside of the inner cuff wall is not covered by the inner cuff wall of the cuff 52 or the corresponding sealing section 51, but is exposed. In an intermediate position, at least a residual open cross-section remains, while in the ventilation position, which is indicated here by the dash-dot lines, the opening of the through-hole facing the inside of the inner cuff wall is completely covered by the inner cuff wall of the cuff 52 or the corresponding sealing section 51.the relevant sealing section 51 is covered and thus sealed.

[0156] Fig. 6 shows a side view of a cross-sectional representation of an overlap area of ​​the outlet seat 50 with an outlet seat guide 45 with a second throttling element 65" according to a third exemplary embodiment. The cross-sectional representation relates to the inner sleeve wall and the inner guide wall section.

[0157] In the second embodiment, the second throttle element 65" is designed as an angled channel, so that the opening of the second throttle element 65" to be concealed, which faces the inside of the inner cuff wall, can be defined as having a cross-section independent of any channel guide path in the direction of movement of the outlet seat 50. In other words, the cross-sectional area of ​​the opening of the second throttle element 65" facing the inside of the inner cuff wall is more limited compared to a pocket. Here, too, the dash-dot lines indicate the ventilation position as opposed to the venting position shown. This also applies to Figures 7 to 9.

[0158] Fig. 7 shows a top view of a cross-sectional view perpendicular to the direction of movement of the outlet seat 50 in an overlap area of ​​the outlet seat 50 with the outlet seat guide 45 with a second throttling element 65"' according to a fourth exemplary embodiment. Specifically, Fig. 7 shows the top view of the cross-sectional view of the inner guide wall section of the outlet seat guide 45 and the inner sleeve wall of the sleeve 52, which here forms a sealing section 51 in the overlap area.

[0159] The second throttle element 65 is designed as a pocket, similar to the first embodiment, except that the pocket is not formed in the inner guide wall section of the outlet seat guide 45, but rather in the inner cuff wall of the cuff 52. Its operation is analogous to the description of the first embodiment.

[0160] Fig. 8 shows a side view of a cross-sectional representation of an overlap area of ​​the outlet seat 50 with an outlet seat guide 45 with a second throttling element 65"" according to a fifth exemplary embodiment. The cross-sectional representation relates to the inner sleeve wall and the inner guide wall section.

[0161] The second throttling element 65"" of the fifth embodiment is designed as a through-hole, similar to the second embodiment, but not in the inner guide wall section, rather in the inner cuff wall. In the venting position, the second throttling element 65"" is still located above the inner guide wall section and is therefore exposed. In the ventilation position, the inner cuff wall with the second throttling element 65"" is then in a position in which the opening of the second throttling element 65"" facing the outside of the inner guide wall section is closed by the outside of the inner guide wall section.

[0162] Fig. 9 shows a side view of a cross-sectional representation of an overlap area of ​​the outlet seat 50 with an outlet seat guide 45 and a second throttling element 65 according to a sixth exemplary embodiment. The cross-sectional representation relates to the inner sleeve wall and the inner guide wall section.

[0163] The second throttling element 65 of the sixth embodiment is designed as an angled channel, similar to the third embodiment, but not in the inner guide wall section, rather in the inner cuff wall. In the venting position, the second throttling element 65 is still arranged above the inner guide wall section and is therefore exposed. In the ventilation position, the inner cuff wall with the second throttling element 65 is then in a position in which the opening of the second throttling element 65 facing the outside of the inner guide wall section is closed by the outside of the inner guide wall section.

[0164] The invention is not limited to the described embodiment. In particular, embodiments described elsewhere and

[0165] Further developments of the invention allow the features described above to be combined with one another, provided they are not mutually exclusive. For example, the at least one second throttling element is not limited to an arrangement in the exhaust seat or in the exhaust seat guide, but can also be arranged separately and / or in mutual interaction both in the exhaust seat and in the exhaust seat guide.

[0166] REFERENCE MARK LIST

[0167] 1 Parking brake control device (control unit)

[0168] 2 Supply connection

[0169] 4 Check valve

[0170] 6 Supply Management

[0171] 8 Solenoid valve assembly

[0172] 10 first 2 / 2-way solenoid valve

[0173] 12 second 2 / 2-way solenoid valve

[0174] 14 Control unit

[0175] 16 Incoming stock

[0176] 18 Relay valve

[0177] 20 Tax receipt

[0178] 22 Control line

[0179] 24 Pressure sink

[0180] 26 Feedback line

[0181] 28 Work exit

[0182] 30 first throttle element

[0183] 32 Parking brake signal connection

[0184] 36 Parking brake signal generator

[0185] 38 Work management

[0186] 40 Connection for spring brake cylinder

[0187] 42 Tax Chamber

[0188] 44 Relay valve housings

[0189] 45 Outlet seat guide

[0190] 46 relay pistons

[0191] 48 valve bodies

[0192] 50 outlet seat

[0193] 51 Sealing section

[0194] 52 cuff

[0195] 53 Passage opening

[0196] 54 entrance seats

[0197] 56 Venting 57 Outlet seat chamber

[0198] 58 Chamber of Labour

[0199] 60 Pantry

[0200] 62 Outlet seat spring center 64 Relay piston spring

[0201] 65, 65', 65", 65'", 65"", 65"" second throttle element

[0202] 66 third throttle element

[0203] 67 Relay piston seal

[0204] 68 Shell wall 88 First pressure sensor

[0205] 89 second pressure sensor

Claims

PATENT CLAIMS 1. Relay valve (18) for an electropneumatic control device (1), comprising: a pneumatic control inlet (20) connected to a control chamber (42) of the relay valve (18), a working outlet (28) connected to a working chamber (58) of the relay valve (18), at least one first throttling element (30) arranged such that the working chamber (58) and the control chamber (42) are in throttled flow communication with each other, a supply inlet (16) connected to a supply chamber (60) of the relay valve (18), a double-seat valve (50, 54) with at least one inlet seat (54) and at least one outlet seat (50), a relay piston (46) for actuating the double-seat valve (50, 54) which, within a relay valve housing (44), moves depending on a pressure in the control chamber (42) between a vented position, in which the relay piston (46) the double seat valve (50, 54) is operated in such a manner,that the outlet seat (50) is fully open and the inlet seat (54) is fully closed, and a venting position in which the relay piston (46) actuates the double-seat valve (50, 54) such that the outlet seat (50) is fully closed and the inlet seat (54) is fully open, wherein the working chamber (58) is connected to a vent (56) when the outlet seat (50) is open and to the reservoir chamber (60) when the inlet seat (54) is open, and wherein the relay valve (18) has at least one second throttling element (65, 65', 65”, 65'”, 65''', 65 ) which is arranged such that the working chamber (58) and the vent (56) are at least in an intermediate position of the relay piston (46) between the venting position and the venting position via the at least one second throttling element (65, 65', 65", 65'", 65"", 65 ) together in throttled, flow connection, and that at least one second throttling element (65, 65', 65”, is completely closed in the ventilation position.

2. Relay valve (18) according to claim 1, wherein the at least one second throttling element (65, 65', 65", 65'", 65"", 65 ) is arranged such that the working chamber (58) and the vent (56) are in throttled flow communication with each other via the at least one second throttling element (65, 65', 65", 65'", 65"", 65 ) in the venting position of the relay piston (46) and in the at least one intermediate position of the relay piston (46) between the venting position and the ventilation position.

3. Relay valve (18) according to claim 1 or 2, wherein the vent (56) is formed at least partially by an outlet seat guide (45) on which the outlet seat (50) is guided to be movable between a position in which the outlet seat (50) is fully open and a position in which the outlet seat (50) is fully closed, and wherein the outlet seat (50) and the outlet seat guide (45) have an overlap area in a direction of movement from the fully open to the fully closed position of the outlet seat (50), wherein the at least one second throttling element (65, 65', 65", 65'", 65"", 65) is arranged in a section of the overlap area formed by the outlet seat (50) and / or in a section of the overlap area formed by the outlet seat guide (45).

4. Relay valve (18) according to claim 3, wherein the outlet seat guide (45) has at least two spaced-apart guide wall sections extending in the direction of movement of the outlet seat (50) around the vent (56), which form an outlet seat chamber (57) between them, and wherein the outlet valve seat (50) has a sleeve (52) extending in a double-walled manner from the outlet seat surface facing the relay piston (46) towards the outlet seat guide (45), wherein an outer sleeve wall of the double-walled sleeve (52) as seen from the vent (56) is connected to the outer guide wall section of the The outlet seat guide (45) forms a substantially fluid-tight overlap area around the outer guide wall section at least in the at least one intermediate position of the relay piston (46) between the vent position and the ventilation position, wherein an inner sleeve wall of the double-walled sleeve (52) viewed from the vent (56) forms an overlap area around the inner guide wall section with the inner guide wall section of the outlet seat guide (45) at least in the at least one intermediate position of the relay piston (46) between the vent position and the ventilation position, and wherein the at least one second throttling element (65, 65', 65", 65"', 65"", 65 ) is arranged in a section of the overlap area formed by the inner sleeve wall and / or in a section of the overlap area formed by the inner guide wall section.

5. Relay valve (18) according to claim 5, wherein the outlet seat (50) has at least one through-opening (53) which fluidically connects the working chamber (58) and the outlet seat chamber (57), in particular in a throttled flow connection.

6. Relay valve (18) according to one of the preceding claims, wherein the relay piston (46) is designed as a stepped piston, wherein in particular the area of ​​the relay piston (46) facing the control chamber (42) is larger than the area of ​​the relay piston (46) facing the working chamber (58).

7. Relay valve (18) according to one of the preceding claims, wherein the control chamber (42) is connected to the vent (56) via at least one third throttling element (66) when the relay piston (46) is in the vent position, and wherein the connection between the control chamber (42) and the vent (56) is interrupted via the at least one third throttling element (66) when the relay piston (46) is in the vent position or in the intermediate position.

8. Relay valve (18) according to claim 7, wherein the flow cross-section provided by the at least one third throttling element (66) is larger than the flow cross-section provided by the at least one first throttling element (30).

9. Relay valve (18) according to claim 7 or 8, wherein the at least one third throttling element (66) includes or is formed by at least one through-hole in a wall of the relay piston (46), and wherein an element (67) fixed to the relay valve housing (44), which is designed as a relay piston seal (67) or includes a relay piston seal (67), is provided, which interacts with the at least one third throttling element (66) in such a way that, depending on the position of the relay piston (46) within the relay valve housing (44), the control chamber (42) is connected to the vent (56) via the at least one third throttling element (66) or such a connection is blocked.

10. Relay valve (18) according to one of the preceding claims, wherein the relay piston (46) is preloaded into the venting position by spring means (64).

11. Relay valve (18) according to one of the preceding claims, wherein the outlet seat (50) is loaded by outlet seat spring means (67) in the direction of the inlet seat (54).

12. Electropneumatic control device (1 ) for controlling at least one pneumatic device, comprising: a connection (40) for the at least one pneumatic device, a solenoid valve device (8) controllable by means of an electronic control device (14), a relay valve (18) according to one of claims 1 to 11, the pneumatic control input (20) of which is connected on the one hand to the solenoid valve device (8) and on the other hand to its working output (28) and to the connection (40) for the at least one pneumatic device, and a supply connection (2) for at least one compressed air supply, which is connected on the one hand to the first solenoid valve device (8) and on the other hand to the supply input (16) of the relay valve (18).

13. Electropneumatic control device (1) according to claim 12, wherein the solenoid valve device (8) is formed by at least two 2 / 2-way solenoid valves (10, 12) each having a closed position and a free position, wherein a first 2 / 2-way solenoid valve (10) is connected as an inlet valve between the control input (20) of the relay valve (18) and the supply port (2), and a second 2 / 2-way solenoid valve (12) is connected between the control input (20) of the relay valve (18) and a pressure sink (24), wherein in particular the first 2 / 2-way solenoid valve (10) and the second 2 / 2-way solenoid valve (12) each have a de-energized closed position and an energized free position.

14. Brake system of a vehicle comprising an electropneumatic control device (1 ) according to claim 12 or 13, wherein the pneumatic device to be controlled is a parking brake comprising at least one brake cylinder.

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