Pneumatic valve and valve arrangement with at least one such pneumatic valve

Abstract

Pneumatic valve, comprising a housing (1) in which an air chamber (2) is formed with a supply opening (3) for supplying compressed air into the air chamber (2), a connecting opening (4) connected to the air chamber and an actuator opening (5) for connecting the air chamber (2) to an actuator chamber, wherein an actuator (6) with a movable closing element (7) is arranged in the housing (1), wherein the closing element (7) is formed with a plunger (11) projecting through the actuator opening (5), at the end of which projecting into the air chamber a plate (11a) is formed, on which a sealing element for closing the supply opening (3) is arranged, and with an elastic element (10; 10a) which presses the plate (11a) in the direction of the actuator opening (5) in the activated state of the pneumatic valve, the actuator (6) further features: - a circuit board (12) arranged in the actuator chamber, - an actuating element (13) arranged in the actuator chamber, which has an actuating section (14) for acting on the plunger (11) 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, 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 an unenergized state, in which it presses the plunger (11) against the supply opening (3), and in an energized state to bring the actuating element (13) into a second state in which the actuating section (14) exerts no force on the plunger (11), so that, due to the action of the elastic element (10), the plate (11a) is pressed in the direction of the actuator opening (5), characterized by that a sealing sleeve (30) is arranged between the plate (11a) and the actuator opening (5) around the plunger (11), which seals the air chamber (2) against the actuator chamber in every state.

Description

[0001] The invention relates to a pneumatic valve, comprising a housing in which an air chamber is formed with a supply opening for supplying compressed air into the air chamber, a connecting opening connected to the air chamber, and an actuator opening for connecting the air chamber to an actuator chamber, wherein an actuator with a movable closing element is arranged in the housing, wherein the closing element is formed with a plunger projecting through the actuator opening, at the end of which projecting into the air chamber a plate is formed, on which a sealing element for closing the supply opening is arranged, and with an elastic element pressing the plate in the activated state of the pneumatic valve towards the actuator opening, wherein the actuator further comprises: a printed circuit board arranged in the actuator chamber, an actuating element arranged in the actuator chamber,which has an actuating section for acting on the plunger and a bending section connected to the actuating section and the circuit board, and an actuator element arranged in the actuator chamber, which has a first end mechanically connected to the actuating section and a second end mechanically and electrically connected to the circuit board, wherein the actuator element is designed, in a de-energized state, to bring the actuating element into a first state in which it presses the plunger against the supply opening, and in a energized state, to bring the actuating element into a second state in which the actuating section exerts no force on the plunger, so that due to the action of the elastic element, the plate is pressed towards the actuator opening.

[0002] Such a pneumatic valve is known from DE 10 2018 216 874 A1 and also from DE 10 2019 208 051 A1. However, in these valves, fluid bubbles or air cushions connected to the connecting opening deflate when the valves are not activated, as there is an open connection between the connecting opening and the actuator opening, and the actuator chamber is connected to the environment to create ambient pressure in the actuator chamber. These are therefore 3 / 2-way valves that not only allow the air cushions to be vented, but also cause them to deflate when the actuator is not activated.

[0003] In vehicles, fillable, elastic cushions are used to shape seat contours. The elastic cushions are usually filled with air. Electrically operated valves are used to control the air flow. The cushions can also be used for a massage function by periodically filling and emptying them. Two or more air cushions are controlled for the massage function. These can be adjusted independently of one another or can remain in an inflated state while other cushions are filled or deflated. Due to the short retention time of the air in a cushion during a massage use compared to a contour adjustment (a few seconds to around 10 minutes), NO valves (“normally open”) are usually used for this purpose; these are in the deflation position when not actuated.

[0004] Increasingly, mid-range and lower-class vehicles are also being equipped with such systems. Therefore, the most cost-effective design possible is required. At the same time, vehicles are being designed to be lightweight to meet environmental and fuel consumption standards. This leads, among other things, to more compact seat designs. This also requires the smaller components installed within them.

[0005] In many designs, such as pneumatic lumbar supports, independent 2 / 2 valves are used for filling and deflation for each cushion installed in a vehicle seat. Consequently, each cushion requires two valve actuators. Alternatively, instead of two 2 / 2 valves, a combination such as 3 / 3 or 3 / 4 valves can be used (also with two actuators). Shape memory alloys (SMA), which have a particularly high power density, are increasingly being used as actuators for pneumatic valves.

[0006] For existing valves with SMA actuators, there are basically two variants regarding the placement of the SMA element. The first group involves complete separation between the fluid and the SMA element. This is particularly necessary (but not exclusively) in hydraulic systems to prevent the SMA element from being exposed to the strong cooling effect of the fluid.

[0007] In EP 2 239 486 A1, the separation occurs via a sliding sealing ring, while in WO 2014 / 135 909 A1, it occurs via an elastic membrane. The disadvantage of this is the additional actuating force required by the actuator. In the case of a sealing ring, this is caused by the friction of the sealing ring. In the case of a membrane, the effective pressure area of ​​the membrane is significantly larger than the actual nozzle opening, which increases the required force and thus the size and / or cost of the actuator.

[0008] A second group uses an SMA element located within a pressure chamber through which fluid flows. According to DE 10 2005 060 217 B4, this is usually connected to the valve's working port. When the SMA actuators are activated, this pressure chamber is then connected either to the supply pressure or the exhaust air. Alternatively, the pressure chamber containing the SMA element is permanently connected to the supply pressure. In both cases, the entire installation space containing the SMA element must be sealed from the environment. This requires an appropriate seal (elastomer, adhesive, or similar) as well as means for absorbing the resulting pressure forces, such as screwing, welding, etc. Costs also arise for contacting the circuit board (or its area) in the pressure chamber from outside, e.g., via airtight feedthrough contacts, an increased number of circuit board layers, or similar.

[0009] All of this increases the required installation space and the cost of the valve.

[0010] Similarly, CN 1 12 066 032 A shows an SMA valve with pulling actuation of the valve element by a rod penetrating the vent valve.

[0011] CN 1 12 066 040 A alternatively shows a sealing sleeve that seals the rod and the valve element from the housing opening, so that the SMA element remains outside the pressure area, but no air can escape through the opening for the plunger. However, this sealing sleeve also acts as a spring, closing the valve when the actuator is not actuated. When the actuator is actuated, the actuator must therefore also apply the force to compress this sealing sleeve.

[0012] The object of the invention is to provide a pneumatic 2 / 2-NC valve with an SMA actuator operating at ambient pressure that is as simple, space-saving, and cost-effective as possible. At the same time, the air flow through the valve should be sealed from the environment. Valve assemblies with such a pneumatic valve should also be provided.

[0013] This object is achieved by a pneumatic valve according to claim 1. Advantageous further developments are specified in the subclaims. Valve arrangements with an advantageous pneumatic valve are specified in CN 1 12 066 040 A.

[0014] Accordingly, in a generic pneumatic valve, a sealing sleeve is arranged between the plate and the actuator opening around the plunger, which seals the air chamber against the actuator chamber in any condition.

[0015] As a result, the compressed air in the air cushion cannot escape through the actuator opening into the actuator chamber and thus to the actuator element, which is designed as an SMA actuator, and possibly change its state through, for example, pressure or temperature changes.

[0016] In an advantageous embodiment of the pneumatic valve, the sealing sleeve is conical or double-conical in shape, whereby it is pressed against the plate of the plunger and around the actuator opening when pressure is applied, thus increasing the seal.

[0017] The double cone has an internal through-hole through which the plunger is inserted.

[0018] In a further advantageous embodiment of the pneumatic valve, the sealing sleeve has an internal stress and, due to this internal stress, seals the air chamber against the actuator chamber in any condition.

[0019] Particularly in the case of a double cone shape, the sealing sleeve can be installed with a pre-tension between the plate of the tappet and the wall of the air chamber using an elastic material.

[0020] In one embodiment of the pneumatic valve, the elastic element is arranged between the plate and the wall of the air chamber having the actuator opening.

[0021] Alternatively, the elastic element can also be arranged between a plate arranged at the end of the tappet outside the air chamber and an outer wall of the air chamber.

[0022] It is essential that when the SMA actuator is actuated, the plunger is pushed or pulled by the elastic element towards the actuator opening against the spring force of the sealing sleeve, thus releasing the supply opening.

[0023] The elastic element can be formed with a spiral spring, but any other form of spring, such as a disc spring or similar, is also conceivable.

[0024] An advantageous valve arrangement is formed with two pneumatic valves according to the invention in that the connection opening of a first valve is connected to a compressed air connection of the valve arrangement and the supply opening of the first valve is connected to an air cushion connection of the valve arrangement and the supply opening of a second valve is connected to the air cushion connection of the valve arrangement and the connection opening of the second valve is connected to an ambient connection of the valve arrangement.

[0025] The two 2 / 2-way NC valves can be combined to create a 3 / 3-way NC valve. One of the 2 / 2-way valves serves for filling and the other for venting. The sealing sleeve on the vent valve can also be omitted.

[0026] A further valve arrangement with at least one pneumatic valve according to the invention and a 3 / 2-valve is formed by connecting a supply opening of the 3 / 2-valve to a compressed air connection of the valve arrangement and a connection opening of the 3 / 2-valve to the connection opening of the at least one pneumatic valve and the supply opening of the at least one pneumatic valve to the air cushion connection of the valve arrangement and an actuator opening of the 3 / 2-valve to an ambient connection of the valve arrangement.

[0027] With this alternative valve arrangement, the consumer, for example an air cushion, can be filled with air when both valves are actuated. For venting, however, only the 2 / 2-way valve according to the invention is activated; the air then escapes into the atmosphere through the vent opening of the non-actuated 3 / 2-way valve. In this way, a single 3 / 2-way valve can also serve as a pilot valve for several 2 / 2-way valves and their consumers connected in parallel.

[0028] For this purpose, at least two pneumatic valves according to the invention are connected with their connecting openings to the connecting opening of the 3 / 2 valve, so that the 3 / 2 valve functions as a pilot valve.

[0029] The invention will be explained in more detail below using exemplary embodiments with the aid of figures. Fig. 1 shows a first embodiment of a pneumatic valve according to the invention in the unactuated state, Fig. 2 the first design variant of the valve in the actuated state during a filling process, Fig. 3 a second embodiment of a pneumatic valve according to the invention in the unactuated state, Fig. 4 the second design variant of the valve in the actuated state during a filling process, Fig. 5 a double-conical sealing sleeve, Fig. 6 a detailed view of the air chamber with a sealing sleeve. Fig. 7 a first embodiment of a valve arrangement and Fig. 8 a second embodiment of a valve arrangement.

[0030] Fig. 1 shows a pneumatic valve in a cross-sectional view, which is formed with a housing 1 having a first housing part 17, which in the illustrated embodiment is designed as a base plate. The housing 1 also has a second housing part 18, which is 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 connection 27 and a connection connection 28 are formed. An actuator chamber is formed between the third housing part 19 and the second housing part 18, in which an actuator 6 is installed.

[0031] An air chamber 2 is formed on the third housing part 19 by having a cup-shaped portion into which a closure piece 2a is inserted as the cover of the air chamber 2. The connection between the cup-shaped portion and the closure piece 2a is established, for example, by means of a press fit or a seal. It can be advantageous if the pressure and sealing forces are absorbed by clipping, screwing, etc.

[0032] The air chamber 2 has a supply opening 3, a connection opening 4, and an actuator opening 5. In the illustrated embodiment, the supply opening 3 and the connection opening 4 are formed in the third housing part 19, and the actuator opening 5 is formed in the end part 2a that closes off the air chamber 2. Compressed air can therefore be fed into the housing 1 via the supply connection 27, for example from a compressor, whereby the compressed air can reach the air chamber 2 via the supply opening 3 and from there via the connection opening 4 and the connection connection 28 into an air cushion that can be connected to it. On the other hand, compressed air can reach the air chamber 2 from the connection connection 28 and the connection opening 4 and from there back to the supply opening, and be released if there is no higher pressure there.

[0033] In the air chamber 2, a closing element 7 is formed with a plunger 11, at the end of which protrudes into the air chamber 2 a plate 11a is arranged or formed thereon.

[0034] At the end of the plunger 11 protruding from the air chamber 2, a further plate 11b is attached or molded onto which an elastic element 10, for example in the form of a coil spring, rests. The elastic element 10 rests with its other end on the end piece 2a. When the valve is activated, the elastic element 10 pushes the closing element 7 away from the supply opening 3, thus opening it.

[0035] In the air chamber 2, a sealing sleeve 30 is arranged around the tappet 11 between the plate 11a and the air chamber wall, in particular the end part 2a, and seals the actuator opening 5 so that the pressure in the air chamber 2 cannot equalize in the actuator chamber defined by the housing parts 18 and 19. Thus, air in an air cushion connected to the connecting port 28 cannot escape through the actuator opening 5, neither in the actuated nor in the deactuated state of the valve.

[0036] The sealing sleeve 30 is advantageously designed as a double cone with an inner bore for the tappet 11 and in one embodiment in the Fig. 5 shown in perspective. According to Fig. 6, in the event of an overpressure in the air chamber 2, the sealing sleeve 30 is pressed against the plate 11a and the end part 2a of the air chamber 2 in addition to its prestress.

[0037] An actuator 6 is also arranged in the housing 1. The actuator 6 is formed with a circuit board 12, which is mounted and mechanically connected to corresponding struts of the third housing part 19. Connected to the circuit board 12 is an actuating element 13, which has an actuating section 14 that is in direct contact with the plunger 11 and has a bending section 15 that is connected to the circuit board 12.

[0038] The actuator 6 further comprises an actuator element 16, which is preferably formed with a wire made of a shape memory alloy that shortens when subjected to current supplied by a circuit (not shown) on the printed circuit board 12. In the non-activated state, the actuating element 13 is preloaded such that the actuating element 13 presses with its actuating section 14 against the plunger 11 and thus presses the plate 11a and any sealing element attached thereto against the force of the elastic element 10 against the supply opening 3, whereby the actuator opening 5 is opened but sealed by the sealing sleeve 30.

[0039] The actuator element 16 is connected - for example by means of crimp connections - both to the actuating element 13 and to the circuit board 12.

[0040] Advantageously, the actuator element 16 is formed above a top side 20 of the circuit board 12, and the actuating element 13 is formed below a bottom side 21 of the circuit board 12, resulting in a very compact design. In principle, the design can also be mirror-inverted, 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.

[0041] 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 enables a current flow, whereby it is detected 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.

[0042] In the Fig. 2 is the valve of the Fig. 1 in a second, activated state, i.e. in a state in which the supply opening 3 is open and air can flow from the supply connection 27 via the connecting connection 28 through the air chamber 2 into a connected air cushion.

[0043] In the Fig. 2, the same parts are provided with the same reference numerals as in Fig. 1, where for reasons of clarity only the essential reference symbols are shown.

[0044] By activating the actuator 6, the actuating element 13 is raised, and the closing element 7 is also pushed upward by the spring force of the elastic element 10, thus compressing the sealing sleeve 30. The closing element 7 no longer presses on the plate 11a, so that it is lifted by the air pressure and releases the supply opening 3.

[0045] In the Fig. 3 and Fig. Figure 4 shows a second embodiment of a pneumatic valve. The same parts as in the Fig. 1 to 3 are provided with the same reference numerals.

[0046] In the second embodiment, the elastic element 10a is now arranged between the plate 11a attached to the end of the plunger 11 projecting into the air chamber 2 and the bottom of the air chamber 2 and is compressed by the latter due to the force of the actuating element 13 on the plunger 11.

[0047] In the Fig. 3 and Fig. 4 the same two states are shown as in the Fig. 1 and Fig. 2, the difference is only in the arrangement of the elastic element 10a.

[0048] The Fig. 7 shows a valve arrangement with two pneumatic valves as shown in the Fig. 3 and Fig. 4; valves could also be used according to the design of the Fig. 1 and Fig. 2 can be used. The connection port of a second valve V2 is connected to a compressed air connection P of the valve arrangement, and the connection port of the second valve V2 is connected to an air cushion connection A of the valve arrangement. The supply port of the second valve V2 is connected to the supply port of the first valve V1, and the connection port of the first valve is connected to an ambient connection R of the valve arrangement.

[0049] With this connection of the two 2 / 2-NC valves, a 3 / 3-NC valve is realized, in which the second valve V2 is used to fill an air cushion connected to the air cushion connection A and the first valve V1 is used to vent it.

[0050] In the Fig.Figure 8 shows another valve arrangement with at least one pneumatic valve V1 with a sealing sleeve 30 and a 3 / 2-way valve V32, which forms a 3 / 2-NC valve. There, a supply port of the 3 / 2-way valve V32 is connected to a compressed air connection P of the valve arrangement, a connection port 4 of the 3 / 2-way valve V32 is connected to the connection port 4 of the at least one pneumatic valve V1, and the supply port 3 of the at least one pneumatic valve V1 is connected to the air cushion connection A1 of the valve arrangement. An actuator port of the 3 / 2-way valve V32 is connected to an ambient connection R of the valve arrangement.

[0051] In this embodiment of a valve arrangement, it is possible that at least two pneumatic valves V1 with a sealing sleeve, as described above, are connected with their connecting openings to the connecting opening of the 3 / 2-way valve V32, so that the 3 / 2-way valve V32 acts as a pilot valve for this number of valves V1.

Claims

[1] Pneumatic valve, comprising a housing (1) in which an air chamber (2) is formed with a supply opening (3) for supplying compressed air into the air chamber (2), a connecting opening (4) connected to the air chamber and an actuator opening (5) for connecting the air chamber (2) to an actuator chamber, wherein an actuator (6) with a movable closing element (7) is arranged in the housing (1), wherein the closing element (7) is formed with a plunger (11) projecting through the actuator opening (5), at the end of which projecting into the air chamber a plate (11a) is formed, on which a sealing element for closing the supply opening (3) is arranged, and with an elastic element (10; 10a) pressing the plate (11a) in the activated state of the pneumatic valve in the direction of the actuator opening (5), wherein the actuator (6) further comprises: - a circuit board (12) arranged in the actuator chamber, - an actuating element (13) arranged in the actuator chamber, which has an actuating section (14) for acting on the plunger (11) 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, which has a first end mechanically connected to the actuating section (14) and a second end mechanically and electrically connected to the circuit board (12), wherein the actuator element (16) is designed to bring the actuating element (13) into a first state in which it presses the plunger (11) against the supply opening (3) in a de-energized state, and to bring the actuating element (13) into a second state in which the actuating section (14) exerts no force on the plunger (11), so that due to the effect of the elastic element (10) the plate (11a) is pressed in the direction of the actuator opening (5), characterized by , that a sealing sleeve (30) is arranged between the plate (11a) and the actuator opening (5) around the tappet (11), which seals the air chamber (2) against the actuator chamber in any state. [2] Pneumatic valve according to claim 1, characterized by that the sealing sleeve (30) is conical or double-conical. [3] Pneumatic valve according to claim 1 or 2, characterized bythat the sealing sleeve (30) has an internal stress and, due to this internal stress, seals the air chamber (2) against the actuator chamber in any state. [4] Pneumatic valve according to one of claims 1 to 3, characterized by that the elastic element (10a) is arranged between the plate (11a) and the wall of the air chamber (2) having the supply opening (3). [5] Pneumatic valve according to one of claims 1 to 3, characterized by that the elastic element (10) is arranged between a plate (11b) arranged at the end of the tappet (11) lying outside the air chamber (2) and an outer wall of the air chamber (2). [6] Pneumatic valve according to one of the preceding claims, wherein the elastic element (10; 10a) is formed with a spiral spring. [7] Valve arrangement with two pneumatic valves (V1, V2) according to one of claims 1 to 6, in which the connecting opening (4) of a first valve (V2) is connected to a compressed air connection (P) of the valve arrangement and the supply opening (3) of the first valve (V2) is connected to an air cushion connection (A) of the valve arrangement and the supply opening (3) of a second valve (V1) is connected to the air cushion connection (A) of the valve arrangement and the connecting opening (4) of the second valve (V1) is connected to an ambient connection (R) of the valve arrangement. [8] Valve arrangement with at least one pneumatic valve (V1) according to one of claims 1 to 6 and a 3 / 2-way valve (V32), in which a supply opening (3) of the 3 / 2-way valve (V32) is connected to a compressed air connection (P) of the valve arrangement and a connection opening (4) of the 3 / 2-way valve (V32) is connected to the connection opening (4) of the at least one pneumatic valve (V1) and the supply opening (3) of the pneumatic valve (V1) is connected to the air cushion connection (A1) of the valve arrangement and an actuator opening (5) of the 3 / 2-way valve (V32) is connected to an ambient connection (R) of the valve arrangement. [9] Valve arrangement according to claim 8, in which at least two pneumatic valves (V1) according to one of claims 1 to 6 are connected with their connecting openings (4) to the connecting opening of the 3 / 2-way valve (V32), so that the 3 / 2-way valve (V32) functions as a pilot valve.

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