Pneumatic valve

Abstract

Pneumatic valve, comprising a housing (1) in which a valve chamber (2) is arranged having a first opening (3) for connection to a first housing gas port (27), a second opening (4) for connection to a second housing gas port (28) and a third opening (5) for connection of the valve chamber (2) to an actuator chamber (30) which is connected to a third housing gas port (29), wherein an SMA actuator (6) with a movable closing element is arranged in the housing (1), wherein the closing element is formed with a plunger (7) projecting through the third opening (5), at the end of which projecting into the valve chamber (2) a sealing plate (11) is formed, on which a first sealing element (11a) for closing the first opening (3) and a second sealing element (11b) for closing the third opening (5) is arranged, wherein a spring element (10, 10', 20') which presses the second sealing element (11b) in the activated state of the pneumatic valve towards the third opening (5) is in operative connection with the closing element, characterized by that the plunger (7) and the actuator (6) have a positive locking connection with clearance via a drive element (20; 20'; 20"), so that by actuating the actuator (6) the plunger (7) is moved by the actuator (6) to the extent of the clearance.

Description

[0001] The invention relates to a pneumatic valve with a housing in which a valve chamber is arranged having a first opening for connection to a first housing gas port, a second opening for connection to a second housing gas port, and a third opening for connecting the valve chamber to an actuator chamber which is connected to a third housing gas port, wherein an SMA actuator with a movable closing element is arranged in the housing, wherein the closing element is formed with a plunger projecting through the third opening, at the end of which projecting into the valve chamber a plate is formed on which a first sealing element for closing the first opening and a second sealing element for closing the third opening are arranged.wherein a spring element, which presses the second sealing element towards the third opening in the activated state of the pneumatic valve, is in operative connection with the closing element.

[0002] Such a pneumatic valve is known from DE 10 2018 216 874 A1 and also from DE 10 2019 208 051 A1. In these valves, when the actuator is not actuated, the first opening of the valve chamber is closed by the first sealing element. When the actuator is actuated, the plunger is pushed by the force of the spring element from the first opening to the third opening, thereby closing it with the second sealing element. The first and second sealing elements can be formed in one piece from a soft material and connected to the plunger, which is made of a harder material. However, they can also be mounted on a plate formed at the end of the plunger located in the valve chamber.

[0003] Such pneumatic valves are used, for example, in vehicles to shape seat contours using inflatable, elastic cushions. These elastic cushions are typically filled with air gas. Electrically actuated pneumatic valves are used to control the air supply. For static contour adjustment, a long holding time (hours to days) is required, thus placing high demands on the tightness of the associated pneumatic valves.

[0004] Prolonged contact time of a valve in the closed position can lead to increased adhesion (sticking) of a sealing element to the nozzle seat, also due to changing environmental influences such as temperature fluctuations. When the valve is subsequently actuated, this sealing element may not be able to be detached, or not within the intended time, by an opening-assisted elastic element (e.g., an internal spring). Furthermore, additional force may be required to open the valve if it is to be opened against a pressure differential at certain operating points.

[0005] The increasingly used SMA (Shape Memory Alloy) actuators have limited force reserves, especially with frequent actuation. If an opening-assistive internal spring, as shown in the aforementioned documents, is applied to the sealing element with sufficient force, this force must be additionally applied by the SMA actuator with each valve actuation. This reduces its service life. In contrast, a sporadically higher force requirement (e.g., only during initial actuation after a longer period of inactivity) appears acceptable with regard to its impact on the service life of the SMA actuator.

[0006] German patent DE 10 2018 112 090 A1 describes an SMA actuator that can exert an increased opening force on the sealing element when required, by actively pulling the sealing element away from the nozzle seat. For this to work, however, the SMA actuator must be located within the pressure chamber of the valve.

[0007] DE 10 2017 213 744 B3 discloses a pneumatic valve in which the sealing element is moved by means of a rotary motion. This assists the detachment from the nozzle seat by a peeling motion.

[0008] In DE 10 2022 207 882 B3 an integrated check valve is described which can be opened with the support of the pre-pressure against a strong return spring.

[0009] In the unpublished German patent application DE 10 2023 203 271 A1, a valve arrangement is described in which a 3 / 3 valve is represented by interconnected 3 / 2 and 2 / 2 valves. The SMA actuator is located in a pressureless space (i.e., at ambient pressure).

[0010] DE 10 2022 202 438 A1 discloses a pneumatic valve with an air chamber in the housing, which has an inlet, a connection, and a drain port. A movable closing element with a sealing element closes the drain port, supported by an elastic element. The actuator is designed as a shape memory actuator (SMA) that moves the plunger into two states depending on the current supply. A check valve is also integrated into the air chamber.

[0011] DE 10 2016 219 342 A1 discloses a pneumatic valve with a housing in which an air chamber with several air ports is arranged. These ports are opened or closed via a movable valve flap. The valve flap is mechanically coupled to a shape memory actuator (SMA element) that deforms when current is supplied, thus moving the flap. A leaf spring converts the small stroke of the SMA element into a larger stroke of the valve flap.

[0012] DE 10 2016 112 115 A1 discloses a linear valve actuator with a piezoelectric actuator that moves a valve closure element axially between the open and closed positions via an actuating device. The actuator is arranged in the actuator housing and supported on the actuating device. An adjustment device allows for the adjustment of the idle stroke. A corresponding valve is also described.

[0013] The object of the invention is to provide a valve with an SMA actuator for use at ambient pressure, in which the opening can be actively assisted by the actuator. Optionally, this additional force should be limited to protect the actuator.

[0014] The problem is solved in a pneumatic valve of this type by the fact that the plunger and the actuator have a positive locking connection with clearance via a drive element, so that when the actuator is actuated, the plunger is moved by the actuator within the scope of the clearance.

[0015] The actuator arrangement is designed to exert both a compressive and a tensile force on the plunger, either to close the first opening or to assist in removing the first sealing element from the first opening. However, due to the play in the drive element, the actuator's force is only effective if the first sealing element is difficult to release from its sealing seat at the first opening, meaning that any existing spring force is insufficient.

[0016] In a design of the pneumatic valve, the actuator further features: a printed circuit board arranged in the actuator chamber, an actuating element arranged in the actuator chamber having an actuating section for acting on the plunger and a bending section connected to the actuating section and the printed circuit board, and an actuator element arranged in the actuator chamber having a first end mechanically connected to the actuating section and a second end mechanically and electrically connected to the printed circuit board, wherein the actuator element is configured to bring the actuating element into a first state in which it presses the plunger against the first opening when the current is off, and to bring the actuating element into a second state in which the actuating section does not exert a pressing force on the plunger when the current is applied.so that, due to the action of the drive element and the spring element, the second sealing element is pulled or pushed towards the third opening.

[0017] When the SMA actuator is actuated, i.e., when the actuator element is energized, it shortens, so that the actuating section of the actuating element is pulled away from the plunger and no longer exerts a direct force on it. The plunger would then, due to the spring force of the spring element, push or pull the first sealing element attached to it away from the first opening and push or pull the second sealing element towards the third opening. However, if the first sealing element is stuck to the sealing seat of the first opening, after overcoming the play, the drive element engages the plunger and, in addition to the spring force, pulls the sealing element away from the first opening. Afterwards, the spring element again takes over the plunger movement, and the actuating element no longer exerts any force on the plunger.

[0018] In an advantageous embodiment of the pneumatic valve, the spring element is formed by a spiral spring inside or outside the valve chamber, which is supported on the housing part or the end part and pushes the plunger from the second opening to the third opening.

[0019] In principle, any other suitable spring can be used, but a coil spring is advantageous due to the mostly concentric design of the valve chamber.

[0020] In an alternative design of the pneumatic valve, the spring element is formed by a leaf spring, which is formed on the actuating section of the actuator and which also functions as a drive element.

[0021] This allows the force of the drive element to be adjusted using the spring constant, so that a maximum force only acts at maximum deflection of the leaf spring, which decreases again when the tappet or sealing element moves.

[0022] Advantageously, the drive element is fixedly connected to the actuating section of the actuator and movably connected to the plunger in such a way that it is carried along with the actuating section when the actuator is actuated and takes the plunger with it after the end of the game has been reached.

[0023] The driving element can be rod-shaped and guided in recesses of the actuating section and a plunger section, and has widenings at its ends that are larger than the cross-section of the recesses.

[0024] This allows the drive element to be movable, but its movement is prevented from sliding through the recesses by the widening, so that it can exert its effect and consequently a pulling force on the plunger when the end of the game is reached.

[0025] Alternatively, the drive element can also be permanently connected to, for example, the actuation section of the actuator.

[0026] This can be advantageous from a manufacturing perspective and also prevents the drive element from being lost.

[0027] The drive element can also be rigidly connected to the spring element located outside the valve chamber, which advantageously reduces the number of individual parts.

[0028] The drive element can have a spring-loaded section, whereby a variable force is exerted on the plunger when the actuator is actuated.

[0029] The actuator assembly is designed to exert both a downward compressive force and an upward tensile force on the plunger. The actuator assembly can be a single piece or a composite component.

[0030] The invention is explained in more detail below using exemplary embodiments and the accompanying figures. Fig. 1 a first embodiment of a pneumatic valve according to the invention in the unactuated state, Fig. 2 the first training variant of the valve in actuated state during a filling process, Fig. 3 a detailed view of a pneumatic valve according to the invention in the unactuated state, Fig. 4 a detailed view of the first training variant of the valve in an actuated intermediate state, Fig. 5 a detailed view of the first design variant of the valve in the open end state, Fig. 6 a detailed view of a second embodiment of a pneumatic valve according to the invention in the unactuated state, Fig. 7 a detailed view of the second design variant of the valve in an actuated intermediate state, Fig. 8 a detailed view of the second design variant of the valve in the open end state, Fig. 9 a detailed view of a third embodiment of a pneumatic valve according to the invention in the unactuated state, Fig. 10 a detailed view of the third training variant of the valve in an actuated intermediate state, Fig. 11 a detailed view of the third design variant of the valve in the open end state.

[0031] Fig. Figure 1 shows a pneumatic valve in cross-sectional view, formed by a housing 1 which has a first housing part 17, designed as a base plate in the illustrated embodiment. The housing 1 also has a second housing part 18, designed as a cover, and finally a third cup-shaped housing part 19, which is designed as an insert between the first and second housing parts 17, 18 and to which a supply port 27 and a connecting port 28 are integrally formed. An actuator chamber 30 is formed between the third housing part 19 and the second housing part 18, in which an actuator 6 is installed.

[0032] The third housing part 19 has a valve chamber 2 formed by a cup-shaped recess into which a cover part 2a is inserted. The connection between the cup-shaped recess and the cover part 2a is achieved, for example, by means of an interference fit or a gasket. It can be advantageous if the pressure and sealing forces are absorbed by clipping, screwing, etc.

[0033] The valve chamber 2 has a first opening 3, a second opening 4, and a third opening 5. In the illustrated embodiment, the first opening 3 and the second opening 4 are located in the third housing part 19, and the third opening 5 is located in the closing part 2a that closes off the valve chamber 2. A gas, for example, compressed air, can be supplied to the housing 1 via the supply port 27, for example, from a compressor. The compressed air can then enter the valve chamber 2 via the first opening 3 and from there, via the second opening 4 and the connecting port 28, into an air cushion that can be connected to it. Conversely, compressed air from the air cushion can enter the valve chamber 2 via the connecting port 28 and the second opening 4, and from there return to the supply port and be released if no higher pressure is present there.

[0034] When the pneumatic valve is not actuated, compressed air from an air cushion connected to the connection port 28 can enter the valve chamber 2 via the connection port 28 and the second opening 4, and from there into the actuator chamber 30 via the third opening 5. The second housing part 18 has an outlet opening 29 for connection with, for example, the ambient air, through which the air from the air cushion can then escape into the environment.

[0035] In the valve chamber 2, a closing element with a plunger 7 is formed, at the end of which, projecting into the valve chamber 2, a sealing plate 11 is arranged or integrally formed. On the sealing plate 11, a first sealing element 11a is arranged on the side facing the first opening 3, and a second sealing element 11b is arranged on the side facing the third opening 5, for example, integrally formed, bonded, or otherwise attached. The sealing plate 11 together with the sealing elements 11a and 11b can be made of a softer material than the plunger 7.

[0036] At the end of the plunger 7 protruding from the valve chamber, a widening 8 is formed, which, through its overlap over the plunger pin, forms a point of application for a drive element 20.

[0037] In valve chamber 2, in the Fig. 1 and Fig. In the embodiment shown in Figure 2, a spring element 10, for example in the form of a coil spring, is arranged. The spring element 10 is supported at one end against the wall of the valve chamber 2 in the region of the first opening 3 and at the other end against the sealing plate 11. When the valve is activated, the spring element 10 is intended to push the sealing plate 11 away from the first opening 3, thus opening it. In the final state, the spring element 10 presses the second sealing element 11b against the third opening 5 and seals it.

[0038] An actuator 6 is also arranged in the housing 1. The actuator 6 is formed with a printed circuit board 12, which is mounted and mechanically connected to corresponding struts of the third housing part 19. A control element 13 is connected to the printed circuit board 12. This control element has an actuating section 14 that is in direct contact with the plunger 7 and a bending section 15 that is connected to the printed circuit board 12.

[0039] The actuator 6 further comprises an actuator element 16, preferably formed with a wire made of a shape-memory alloy, which shortens when energized by a current supplied by a circuit (not shown) on the circuit board 12. In the inactive state, the actuating element 13 is pre-tensioned such that its actuating section 14 presses against the plunger 7, thereby pressing the sealing plate 11 and the optionally attached first sealing element 11a against the first opening 3 against the force of the spring element 10.

[0040] The actuator element 16 is connected to both the actuating element 13 and the circuit board 12, for example by means of crimp connections.

[0041] Advantageously, the actuator element 16 is located above a top surface of the circuit board 12 and the actuating element 13 is located below a bottom surface of the circuit board 12, resulting in a very compact design. In principle, the arrangement can also be mirrored, so that the actuator element 16 is located below the circuit board 12 and the actuating element 13 is located above the circuit board 12.

[0042] Advantageously, an end position detection element 26 is formed on the actuating element 13, which comes into contact with the circuit board 12 when the actuator 6 is actuated and allows a current flow, thereby detecting that the end position has been reached, so that the current through the actuator element 16 can be switched off or at least reduced in order not to overload it.

[0043] The pneumatic valve has the actuator element 20, which in the exemplary embodiment of the Fig. 1 and Fig. 2 is firmly connected to the actuating section 14 of the actuating element 13, for example by being molded onto it.

[0044] It can also be glued, soldered, or welded. Other suitable joining methods are possible.

[0045] The plunger 7 has a widening 8 or a recess at its upper end, preferably as part of a hard component. The drive element 20 can engage this widening 8 from below in a force-fit manner and thus exert a tensile force on the plunger 7. Alternatively, the plunger 7 can also have a corresponding indentation against which the drive element 20 can engage. The lower end of the plunger 7 contains the sealing elements 11a, 11b and preferably consists of a soft component.

[0046] In the Fig. 2 is the valve of the Fig. 1 shown in a second, activated state, i.e. in a state in which the first opening 3 is open and air can flow from the supply port 27 via the connecting port 28 through the valve chamber 2 into an attached air cushion.

[0047] In the Fig. 2 and in all subsequent figures, identical parts are provided with the same reference symbols as in Fig. 1, although for the sake of clarity not all reference symbols are always given.

[0048] By activating the actuator 6, the actuating element 13 is raised, and thus the plunger 7 is also pushed upwards by the spring force of the spring element 10. The first sealing element 11a then no longer presses on the first opening 3, so that it opens.

[0049] In the Fig. Figures 3 to 5 are detailed views of the pneumatic valve diagrams. Fig. 1 and Fig. 2 shown. The states shown correspond to the Fig. 3 and Fig. 5 those of Fig. 1 or 2. The condition of the Fig. 4 is an intermediate state in the actuated state, in which the first opening 3 is not yet open due to a sticking first sealing element 11a, since the spring force of the spring element 10 is not sufficient to overcome this sticking.

[0050] Holding the resting state Fig. 1 and Fig. 3. The plunger 7 is pressed onto the lower nozzle seat of the first opening by the restoring force of the actuator 6, thus sealing it. The force of the spring element 10 in the valve chamber 2 is significantly less than the restoring force of the actuator 6. In this state, the drive element 20 has no contact with the widening 8 of the plunger due to the clearance.

[0051] At the start of the opening process (see Fig. 4) The first sealing element 11a may be prevented from opening by adhesion or by a positive pressure differential between the valve chamber 2 and the supply port 27. In this case, the actuating section 14 of the actuator 6 initially lifts up to such an extent that the drive element 20 contacts the widening 8 of the plunger 7 from below and exerts an upward force on the plunger 7 to release the first sealing element 11a from the nozzle seat of the first opening 3.

[0052] As soon as the sealing plate 11 with the first sealing element 11a has detached from the lower nozzle seat ( Fig. 5), it is moved to its upper position by the spring element 10 (e.g., coil spring) and held there by the spring element 10 and, if applicable, by the pressure in the valve chamber 2. Thus, the valve is open and simultaneously seals the third opening 5 by means of the second sealing element 11b. The actuating section 14 of the actuator 6 then moves further to its upper end position, so that it and the drive element 20 no longer touch the plunger 7 in either direction due to the clearance and thus no longer exert any force on the plunger 7.

[0053] The drive element 20 can be - as already explained - either integrally molded onto an actuator part (e.g. as a tab of an injection-molded or stamped-bent part), but can also be mounted in multiple parts as an additional component, e.g. as a clip which can touch the plunger 7 from below and the corresponding actuator part from above and is securely attached to one of these two components.

[0054] In the Fig. Figures 6 to 8 each show a detailed view of a second embodiment of a pneumatic valve according to the invention. Here too, identical parts are provided with the same reference numerals. The same actuation states are shown as in the Fig. Shown 3 to 5.

[0055] The design shown allows the force required by the actuator 6 to be further limited to a maximum permissible value. This may be necessary if the valve requires excessive force to open due to environmental conditions or a malfunction, or if opening does not occur within the intended actuation time of the SMA actuator 6. Both of these scenarios can lead to an overload of the SMA actuator 6 and thus to its premature failure.

[0056] The drive element 20' is designed as a spring element 10 in the form of a leaf spring, which yields under excessive tensile force. This allows the SMA actuator 6 to move further into its end position if the plunger 7 does not release the first sealing element 11a from the lower nozzle seat at the first opening 3. Furthermore, this design eliminates the need for an internal spring element 10 in the valve chamber 2.

[0057] Hold in idle state ( Fig. 6) The plunger, through the restoring force of the actuator 6, presses the first sealing element 11a onto the lower nozzle seat of the first opening 3, thus sealing it. The entire restoring force of the actuator 5 acts on the plunger 7 to apply the sealing force for the lower nozzle seat (i.e., the restoring force is not reduced by the opposing force of an internal spring element 10).

[0058] As soon as the SMA actuator 6 is at the beginning of the opening process (see Fig. 7) When the actuator 6 is lifted, the drive element 20' exerts an upward force on the plunger 7, which increases with increasing stroke. This force is limited to a permissible maximum value by the spring-loaded drive element 20'; this occurs when the SMA actuator 6 reaches its end position, but the plunger 7 is still held in its rest position (e.g., by adhesion to the lower nozzle seat).

[0059] As soon as the plunger 7 has detached from the lower nozzle seat, it is carried along by the actuator 6 until it contacts the third opening 5. During this process, the pressure and tensile forces exerted by the actuator 6 on the plunger 7 cancel each other out.

[0060] Once the plunger 7 has reached its upper position, the valve is fully open (see Fig. 8) The SMA actuator 6 can then move further into its own end position. The drive element 20' now exerts a (limited) tensile force on the plunger 7, pressing it against the upper vent nozzle seat of the third opening 5. This allows the vent nozzle to seal even without the internal spring element 10.

[0061] The pulling element of the SMA actuator 6 can again be integrally formed onto a part of the actuator 6 (e.g. as a tab of an injection-molded or stamped-bent part), but can also be multi-part, mounted as an additional component on the actuator 6 and / or plunger 7, e.g. as a clip which touches the plunger from below and the actuating section of the actuator 6 from above (simultaneously) and is securely attached to one of these two components.

[0062] In a third design, as it appears in the Fig. As shown in Figures 9 to 11, the internal spring element 10 is replaced by a spring element 10' outside the valve chamber 2. This rests against the lower end of the widening 8 of the tappet 7 and is supported on the upper cover of the valve chamber 2. In the open state of the valve (see Figure 9 to 11), the internal spring element 10 is replaced by a spring element 10' outside the valve chamber 2. Fig. 11) This spring element 10' holds the plunger 7 in its upper position.

[0063] Furthermore, a drive element 20" is formed as a tab on the outer spring element 10', which can provide an additional force for opening the valve analogous to the drive element 20.20' of the first and second embodiments, by bearing against the actuator 6 (see Fig. 10). The drive element 20" can also be spring-loaded to limit the maximum force from the actuator 6 to the plunger 7.

[0064] When the valve is fully open, neither the plunger 7 nor the drive element 20" touch the actuator 6 (see Fig. 11).

[0065] In the aforementioned designs, the SMA actuator 6 can, if necessary, apply an increased force to detach an adhesive first sealing element 11a, even if the SMA actuator 6 is not located in the pressure chamber.

[0066] The inner spring element 10 in the valve chamber 2 can be designed for a very low force, since it only needs to move the plunger 7 to the upper end position, but does not serve to detach an adhered first sealing element 11a. This reduces the force that the SMA actuator 6 has to apply regularly and thus increases its service life.

[0067] In an alternative embodiment, an internal spring element 10 can be omitted entirely, since the actuator 6 exerts a corresponding upward force when the valve is actuated, causing the plunger 7 to bear against the upper vent nozzle seat. The maximum acting force can be limited by the force-displacement characteristic of the actuator 6 or the drive element 20'. This prevents excessive stress on the SMA actuator, even in the event of a fault.

[0068] In another embodiment, an external spring element 10' replaces the internal spring element 10 and is also part of the drive element 20".

Claims

[1] Pneumatic valve, comprising a housing (1) in which a valve chamber (2) is arranged having a first opening (3) for connection to a first housing gas port (27), a second opening (4) for connection to a second housing gas port (28) and a third opening (5) for connection of the valve chamber (2) to an actuator chamber (30) which is connected to a third housing gas port (29), wherein an SMA actuator (6) with a movable closing element is arranged in the housing (1), wherein the closing element is formed with a plunger (7) projecting through the third opening (5), at the end of which projecting into the valve chamber (2) a sealing plate (11) is formed, on which a first sealing element (11a) for closing the first opening (3) and a second sealing element (11b) for closing the third opening (5) is arranged, wherein a spring element (10, 10', 20') which presses the second sealing element (11b) in the activated state of the pneumatic valve towards the third opening (5) is in operative connection with the closing element, characterized by , that the plunger (7) and the actuator (6) have a positive locking connection with clearance via a drive element (20; 20'; 20"), so that by actuating the actuator (6) the plunger (7) is moved by the actuator (6) to the extent of the clearance. [2] Pneumatic valve according to claim 1, characterized by , that the actuator (6) further exhibits: a circuit board (12) arranged in the actuator chamber (30), an actuating element (13) arranged in the actuator chamber (30), which has an actuating section (14) for acting on the plunger (7) and a bending section (15) connected to the actuating section (14) and the circuit board (12), and an actuator element (16) arranged in the actuator chamber (30), which has a first end that is mechanically connected to the actuating section (14) and a second end that is mechanically and electrically connected to the circuit board (12), wherein the actuator element (16) is configured to bring the actuating element (13) into a first state in which it presses the plunger (7) against the first opening (3) in an energized state, and to bring the actuating element (13) into a second state in which the actuating section (14) does not exert a pressing force on the plunger (7), so that, due to the action of the drive element (20; 20'; 20") and the spring element (10; 10'), the second sealing element (11b) is pulled or pushed in the direction of the third opening (5). [3] Pneumatic valve according to claim 1 or 2, characterized by, that the spring element (10;10') is formed by a coil spring in or outside the valve chamber (2), which is supported on the housing part (19) or on the end part (2a) and pushes the plunger (7) from the second opening (3) to the third opening (5). [4] Pneumatic valve according to claim 1 or 2, characterized by , that the spring element (20') is formed by a leaf spring which is formed on the actuating section (14) of the actuator (6) and which also functions as a drive element (20'). [5] Pneumatic valve according to one of claims 1, 2 or 4, characterized by , that the drive element (20') is fixedly connected to the actuating section (14) of the actuator (6) and movably connected to the plunger (7) in such a way that when the actuator (6) is actuated, it is carried along with the actuating section (14) and, after reaching the end of the game, carries the plunger (7) along with it. [6] Pneumatic valve according to any one of claims 1 to 3, characterized by, that the drive element (20; 20') is firmly connected to the actuating section (14) of the actuator (6). [7] Pneumatic valve according to claim 3, characterized by , that the drive element (20") is firmly connected to the spring element (10') arranged outside the valve chamber (2). [8] Pneumatic valve according to claim 4, characterized by , that the drive element (20') has a spring section, whereby a variable force is exerted on the plunger (7) when the actuator (6) is actuated.

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