Pneumatic valve

Abstract

A pneumatic valve comprises a housing with an air chamber having supply, connecting and discharge openings. An actuator with a movable closing element is arranged in the housing, featuring a plunger, which projects through the discharge opening with a plate and a first sealing element for closing the discharge opening with an elastic element which, in the activated state, presses said sealing element against the discharge opening The actuator is in the form of an SMA actuator, wherein the actuator element is configured to, in a non-energized state, bring the actuating element to a first state in which it presses the plunger against the supply opening, and to, in an energized state, bring the actuating element to a second state in which the actuating portion does not exert any force on the plunger, wherein a second sealing element is arranged in the air chamber and functions as a check valve.

Claims

1. A pneumatic valve, comprising: a housing in which an air chamber with a supply opening for supplying compressed air into the air chamber, a connecting opening for connecting the air chamber to an air cushion and a discharge opening for discharging compressed air from the air chamber are formed, an actuator with a movable closing element is arranged in the housing, wherein the closing element is formed with a plunger, which projects through the discharge opening and has formed at an end thereof projecting into the air chamber a plate on which a first sealing element for closing the discharge opening is arranged, and with an elastic element which, in the activated state of the pneumatic valve, presses said first sealing element against the discharge opening, wherein the actuator also has: a circuit board, an actuating element which has an actuating portion for acting on the plunger and a bending portion connected to the actuating portion and to the circuit board, and an actuator element which has a first end mechanically connected to the actuating portion and a second end mechanically and electrically connected to the circuit board, wherein the actuator element is configured to, in a non-energized state, bring the actuating element to a first state in which it presses the plunger against the supply opening, and to, in an energized state, bring the actuating element to a second state in which the actuating portion does not exert any force on the plunger, resulting in the discharge opening is being closed by the first sealing element owing to the action of the elastic element, wherein a second sealing element is arranged in the air chamber, said second sealing element, in the non-energized state of the actuator element, closing the supply opening and, in the energized state of the actuator element, opening the supply opening in an event of a positive pressure difference between the pressure at the supply opening and the pressure at the connecting opening and closing the supply opening in the event of a negative pressure difference between the pressure at the supply opening and the pressure at the connecting opening.

2. The pneumatic valve as claimed in claim 1, in which the second sealing element is in the form of a lamella and is anchored with one end in a wall of the air chamber, and in which the elastic element is arranged between a plate formed at that end of the plunger which projects out of the air chamber and an outer wall of the air chamber.

3. The pneumatic valve as claimed in claim 1, in which the second sealing element is in the form of a lamella and is arranged loosely between the supply opening and the plate formed at that end of the plunger which projects into the air chamber.

4. The pneumatic valve as claimed in claim 3, in which the elastic element is arranged between the plate and the second sealing element.

5. The pneumatic valve as claimed in claim 3, in which the second sealing element is formed with a rigid material.

6. The pneumatic valve as claimed in claim 2, in which the second sealing element is formed with an elastic material.

7. The pneumatic valve as claimed in claim 1, in which the elastic element is formed with a spiral spring.

8. The pneumatic valve as claimed in claim 2, in which the elastic element is formed with a spiral spring.

9. The pneumatic valve as claimed in claim 3, in which the elastic element is formed with a spiral spring.

10. The pneumatic valve as claimed in claim 4, in which the elastic element is formed with a spiral spring.

11. The pneumatic valve as claimed in claim 5, in which the elastic element is formed with a spiral spring.

12. The pneumatic valve as claimed in claim 6, in which the elastic element is formed with a spiral spring.

13. The pneumatic valve as claimed in claim 1, in which the elastic element is formed with a spiral spring.

14. The pneumatic valve as claimed in claim 4, in which the second sealing element is formed with a rigid material.

15. The pneumatic valve as claimed in claim 3, in which the second sealing element is formed with an elastic material.

16. The pneumatic valve as claimed in claim 4, in which the second sealing element is formed with an elastic material.

Description

(1) The invention will be explained in more detail below on the basis of exemplary embodiments with the aid of figures. In the figures:

(2) FIG. 1 shows a first embodiment variant of a pneumatic valve according to the invention in a non-actuated state,

(3) FIG. 2 shows the first embodiment variant of the valve in the actuated state during a filling operation,

(4) FIG. 3 shows the first embodiment variant of the valve in the actuated state, after a filling operation, with an active restoring valve,

(5) FIG. 4 shows a second embodiment variant of a pneumatic valve according to the invention in a non-actuated state,

(6) FIG. 5 shows the second embodiment variant of the valve in the actuated state during a filling operation, and

(7) FIG. 6 shows the second embodiment variant of the valve in the actuated state, after a filling operation, with an active restoring valve.

(8) FIG. 1 shows a cross-sectional illustration of a pneumatic valve, which is formed with a housing 1 which has a first housing part 17 in the form of a base plate in the illustrated exemplary embodiment. The housing 1 also has a second housing part 18 which is in the form of a cover, and lastly a third cup-shaped housing part 19 which is in the form of an insert part between the first and the second housing part 17, 18 and on which a supply port 27 and a connecting port 28 are integrally formed.

(9) An air chamber 2 is formed on the third housing part 19, in that the latter has a pot-shaped molding into which a terminating part 2a is inserted as a cover of the air chamber 2. The air chamber 2 has a supply opening 3, a connecting opening 4 and a discharge opening 5. In the illustrated exemplary embodiment, the supply opening 3 and the connecting opening 4 are formed in the third housing part 19, and the discharge opening 5 is formed in the terminating part 2a terminating the air chamber 2. It is thus possible for compressed air to be routed, for example from a compressor, via the supply port 27 into the housing 1, wherein the compressed air can pass via the supply opening 3 into the air chamber 2 and from there via the connecting opening 4 and the connecting port 28 into an air cushion connectable thereto. On the other hand, compressed air from the air cushion can pass via the connecting port 28 and the connecting opening 4 into the air chamber 2 and from there via the discharge opening 5 into the interior of the housing 1, there being an opening 29 to the environment there.

(10) In the air chamber 2, a closing element 7 with a plunger 11 and with a first sealing element 8 is formed, wherein the first sealing element 8 is fastened to or integrally formed on a plate 11a which is connected to or integrally formed on that end of the plunger 11 which projects into the air chamber 2.

(11) A further plate 11b is fastened to or integrally formed on that end of the plunger 11 which projects out of the air chamber 2, an elastic element 10, for example in the form of a spiral spring, being supported on said further plate. The elastic element 10 is supported by way of its other end on the terminating part 2a. When the valve is activated, the elastic element 10 presses the closing element 7 and thus the first sealing element 8 against the discharge opening 5. In the activated state, it is thus not possible for any air from an air cushion connected to the connecting port 28 to escape via the air chamber 2.

(12) In the air chamber 2, a second sealing element 30 is arranged between the plate 11a attached to the plunger 11 and the supply opening 3, and is clamped between the third housing part 19 and the terminating part 2a in the exemplary embodiment of FIG. 1. The second sealing element 30 may be embodied as a rigid or elastic lamella and acts as a leaf spring which can seal the supply opening 3 in the case of a certain force thereon. In the non-activated state of the valve shown in FIG. 1, the closing element 7 presses on the second sealing element 30 and thus presses the latter against the supply opening 3. This makes it possible for air in an air cushion connected to the connecting port 28 to escape via the non-closed discharge opening 5 through the opening 29 in the second housing part 18, thus producing an NO valve.

(13) Moreover, an actuator 6 is arranged in the housing 1. The actuator 6 is formed with a circuit board 12 which is mounted on 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 portion 14 in direct contact with the plunger 11 and has a bending portion 15 connected to the circuit board 12.

(14) The actuator 6 also has an actuator element 16, which is preferably formed with a wire that is composed of a shape memory alloy and contracts when current supplied by a circuit (not illustrated) on the circuit board 12 is applied thereto. In the non-activated state, the actuating element 13 is preloaded in such a way that the actuating portion 14 of the actuating element 13 presses against the plunger 11 and thus presses the second sealing element 30 counter to the force of the elastic element 11 onto the supply opening 3, as a result of which the discharge opening 5 is opened.

(15) The actuator element 16 is connected both to the actuating element 13 and to the circuit board 12 herefor example by means of crimp connections.

(16) Advantageously, the actuator element 16 is formed above an upper side 20 of the circuit board 12 and the actuating element 13 is formed below a lower side 21 of the circuit board 12, such that a very compact construction results. In principle, the structure can also be mirror-inverted, such that the actuator element 16 comes to lie below the circuit board 12 and the actuating element 13 comes to lie above the circuit board 12.

(17) Advantageously, an end position detection element 26 is formed on the actuating element 13, said end position detection element coming into contact with the circuit board 12 when the actuator 6 is actuated and enabling a current flow, as a result of which it is detected that the end position has been reached, with the result that the current can be switched off or at least reduced by the actuator element 16 in order not to overload the latter.

(18) FIG. 2 shows the valve of FIG. 1 in a second, activated state, that is to say in a state in which the supply opening 3 is opened and air can flow from the supply port 27 via the connecting port 28 through the air chamber 2 into a connected air cushion.

(19) In FIG. 2, identical parts are denoted by the same reference signs as in FIG. 1, with only the essential reference signs being shown for reasons of clarity.

(20) As a result of activation of the actuator 6, the actuating element 13 is raised and thus the closing element 7 is likewise pushed upward by the spring force of the elastic element 10 and the discharge opening 5 is consequently closed by the first sealing element 8. The closing element 7 no longer presses on the second sealing element 30, such that the latter is raised by the air pressure and opens the supply opening 3.

(21) Lastly, FIG. 3 shows a third state of the valve in which, when the actuator 6 is activated and thus the closing part 7 closing the discharge opening 5 functions as a check valve, the second sealing element 30 closes the supply opening 3, since the air pressure at the connecting opening 4 or the air chamber 2 is higher than at the supply opening 3 or the supply port 27.

(22) A second embodiment of a pneumatic valve is illustrated in FIGS. 4 to 6. Here, too, identical parts are denoted by the same reference signs as in FIGS. 1 to 3.

(23) In the second embodiment, the second sealing element 31 is in the form of a loose lamella and lies between the closing element 7 and the supply opening, in a largely freely movable manner at least between these parts.

(24) Moreover, the elastic element 10a is now arranged between the plate 11a attached at that end of the plunger 11 which projects into the air chamber 2 and the second sealing element 31 and presses the latter, as illustrated in FIGS. 4 and 6, against the supply opening 3 or is compressed by the second sealing element 31 owing to a high pressure caused by inflowing air at the supply opening 3.

(25) The same three states as in FIGS. 1 to 3 are illustrated in FIGS. 4 to 6, the difference being only in the embodiment of the second sealing element 31, which now no longer functions as a leaf spring, and the elastic element 10a, which now not only presses the first sealing element 8 of the closing element 7 against the discharge opening 5 when the valve is activated, but also presses the second sealing element 31 against the supply opening 3 when the pressure at the supply opening 3 becomes lower, for example because a pressure-generating compressor is switched off.

(26) The advantages of the mentioned embodiments result from a halved number of actuators compared with an arrangement having 3/3-way NO switching valves with comparable function for massage applications, from a cost-effective, space-saving and weight-reducing presentation of a massage with holding function and from a partial compensation of pressure loss, in the event that during a longer holding time of the valve a leak occurs at the check valve, during which further cushions are intended to be filled.