Actuator unit for actuating a valve, and valve with such an actuator unit

Abstract

Actuator unit (AE) for actuating a valve (V) for a pneumatic adjustment device (PV) of a vehicle seat (FZS), comprising: - a printed circuit board (PCB) with an actuating section (AC) for actuating the valve (V) and - a shape memory alloy element (SMA) coupled to the actuating section (BA) which, when electrical energy is supplied, is deformable such that the actuating section (BA) is moved to actuate the valve (V), wherein the actuating section (BA) is defined by a recess (A) in the printed circuit board (PCB).

Description

[0001] The present invention relates to an actuator unit for actuating a valve for a pneumatic adjustment device of a vehicle seat. The present invention further relates to a valve with such an actuator unit.

[0002] Modern vehicle seats incorporate fluid chambers, filled with a pressure medium, particularly a gaseous pressure medium such as compressed air, as actuating elements located in the seat cushion or backrest (collectively referred to as the seat surface). These fluid chambers can be supplied with the pressure medium via a dedicated pressure medium line. Filling or emptying a fluid chamber with pressure medium increases or decreases its volume, thereby altering the properties of the seat surface, especially its contour. To fill the fluid chamber, the pressure medium is first generated by a pressure medium source, such as a compressor or compressor unit, and then directed to the respective fluid chamber via a valve in a control unit.

[0003] Shape memory alloy elements (SMA elements) are frequently used as actuators to operate such valves. These SMA elements are heated by the application of electrical energy, particularly electric current, causing them to change shape. When the electrical energy is removed, the SMA elements cool down and return to their original shape.

[0004] This shape change of the shape memory alloy elements can be used, for example, to actuate a valve. For this purpose, the shape memory alloy element is typically electrically and mechanically connected to a circuit board and coupled to a movable actuator element that serves to open and close a fluid port of the valve.

[0005] However, it has been shown that the use of a shape memory alloy element together with a separate actuator element is particularly complex and costly during the assembly of the valve, as the actuator element must be positioned precisely and accurately in the valve and connected to the shape memory alloy element in a complex manner.

[0006] Document DE 10 2005 060 217 A1 discloses a valve comprising a valve housing and a printed circuit board. A plunger is located in the valve housing and is actuated by means of a ribbon-shaped SMA element. The SMA element is electrically connected to the printed circuit board.

[0007] The object of the present invention is therefore to provide an actuator unit for actuating a valve, in which the use of a separate actuator element can be dispensed with with minimized process and equipment engineering effort. Furthermore, the object is to provide a valve with such an actuator unit.

[0008] These tasks are solved by an actuator unit according to claim 1 and a valve according to claim 10. Advantageous embodiments are the subject of the dependent claims.

[0009] According to a first aspect of the invention, an actuator unit for actuating a valve for a pneumatic adjustment device of a vehicle seat is provided. The actuator unit comprises a printed circuit board with an actuating section for actuating the valve and a shape-memory alloy element coupled to the actuating section. When electrical energy is supplied, the shape-memory alloy element is deformable such that the actuating section is moved to actuate the valve. By integrating the actuating section for actuating the valve into the printed circuit board, it is no longer necessary to provide a separate actuator element for actuating the valve. The actuating section integrated into the printed circuit board thus allows for the creation of an actuator unit with minimized process and tooling effort.

[0010] In the actuator unit according to the invention, the actuating section is defined by a recess in the printed circuit board (PCB). The recess separates the actuating section from the rest of the PCB. This integrates the actuating section into the PCB. The recess can, for example, be a simple slot that separates an area of ​​the PCB from the rest. However, the recess can also be in the shape of a U or V and at least partially enclose an area of ​​the PCB. The area at least partially enclosed by the recess then forms the actuating section of the PCB. By defining the actuating section by a recess in the PCB, an actuating section can be easily created within the PCB.

[0011] According to a further embodiment of the actuator unit, the shape memory alloy element is connected to the actuating section exclusively mechanically. For example, the shape memory alloy element could be a wire whose two ends are electrically and mechanically connected to the circuit board and mechanically coupled to the actuating section in the form of a loop. This design allows the actuating section to be constructed without electrical conductors or contacts for supplying power to the shape memory alloy element, further reducing manufacturing costs.

[0012] However, according to a further embodiment of the actuator unit, it is also conceivable that the shape memory alloy element is electrically and mechanically connected to the actuating section. In this embodiment, the actuating section has electrical conductors or contacts for supplying power to the shape memory alloy element. If the shape memory alloy element is, for example, a shape memory alloy wire, then one end of the wire can be connected to the mounting section and the other end of the wire to the rest of the circuit board. This allows for particularly simple manufacturing of the actuator unit.

[0013] According to a further embodiment of the actuator unit, the circuit board has, in addition to the actuating section, a main section that is connected to the actuating section via a deformation section. The deformation section has a lower stiffness than the main section and / or the actuating section. If, for example, as described above, the actuating section is formed by a slot-shaped recess in the circuit board, the part of the circuit board enclosed by the slot-shaped recess can be used as the actuating section, and the remaining part of the circuit board can be used as the main section, for example, for mounting in a valve housing.Since the actuating section is connected to the main section via a deformation section which has a lower stiffness than the main section and / or the actuating section, it is possible to move the actuating section relative to the main section in order to actuate the valve.

[0014] According to a preferred embodiment, the deformation area has a stiffness-reduced zone to achieve the desired (lower) stiffness. For example, the stiffness-reduced zone can be achieved by a material recess in the printed circuit board (e.g., in the form of small holes). However, it is also possible to achieve the stiffness-reduced zone by using a plasticizer. It is also conceivable that the stiffness-reduced zone comprises a different, particularly softer, material than the main section and / or the actuating section, e.g., rubber or a flexible polymer.

[0015] In a particularly preferred embodiment, the stiffness-reduced zone is formed in the form of a groove, which is specifically designed to allow smooth movement of the actuating section relative to the main section. If the printed circuit board is one with an additional flexible layer (e.g., a polyamide layer or a polyamide film), then the groove can be designed such that it extends down to this flexible layer. The flexibility of the flexible layer can then be used, on the one hand, to achieve the desired (lower) stiffness in the deformation zone and, on the other hand, to increase the movement of the actuating section.

[0016] Furthermore, it is conceivable that the actuating section has a smaller thickness than the main section. This increases the flexibility of the actuating section or reduces its stiffness, thus facilitating its movement.

[0017] According to a further preferred embodiment, the shape memory alloy element is a shape memory alloy wire, one end of which is connected to the main section and the other end of which is connected to the actuating section. This embodiment allows the shape memory alloy element to be easily connected electrically and mechanically to the printed circuit board, specifically to its main section and its actuating section.

[0018] According to a further embodiment of the actuator unit, the actuator unit includes an end-position detection device that detects movement of the actuating section exceeding a predetermined threshold. The use of an end-position detection device can prevent the shape memory alloy element from being subjected to electrical energy (especially current) exceeding a threshold. This can increase the service life of the shape memory alloy element, thus expanding the application range of the actuator unit.

[0019] According to a second aspect of the present invention, a valve for a pneumatic adjustment device of a vehicle seat is provided. The valve comprises a valve housing having a fluid connection and an actuator unit according to the first aspect or embodiments thereof.

[0020] According to a preferred embodiment of the valve, the actuator unit is arranged inside the valve housing such that when electrical energy is supplied to the shape memory alloy element, the actuating section is moved to open the fluid port. Furthermore, in a preferred embodiment, the valve has a return element configured to move the actuating section to close the fluid port when the supply of electrical energy to the shape memory alloy element ceases. By opening the fluid port when electrical energy is supplied to the shape memory alloy element and closing the fluid port when the supply of electrical energy to the shape memory alloy element ceases, the actuator unit can be used in a valve that is closed when not energized (so-called normally closed valve).

[0021] Exemplary embodiments of the invention will now be explained in more detail with reference to the accompanying drawings. These show: Fig. 1 a schematic top view of an actuator unit according to an embodiment of the invention; Fig. 2 a schematic sectional view of a valve with an actuator unit according to an embodiment of the invention, wherein the valve is shown in a closed state; Fig. 3 a schematic sectional view of a valve with an actuator unit according to an embodiment of the invention, wherein the valve is shown in an open state; and Fig. 4 A schematic representation of a pneumatic adjustment device of a vehicle seat which has such a valve.

[0022] The following describes embodiments of the actuator unit used to actuate a valve for a pneumatic adjustment mechanism of a vehicle seat. Naturally, the actuator unit can also be used to actuate valves in other applications.

[0023] Fig. Figure 1 shows a schematic top view of an actuator unit AE used to actuate a valve V ( Fig. 2 to 4) for a pneumatic adjustment device PV (see Fig. 4) can be used.

[0024] The actuator unit AG comprises a printed circuit board LP, which includes an actuation section BA and a main section HA. The main section HA is designed, for example, to mount the printed circuit board LP in a valve housing. The actuation section BA is used to actuate the valve V, as described later in connection with the Fig. 2 to 4 will be described in more detail.

[0025] The actuating section BA is, in the present embodiment, by Fig. 1. The actuating section BA is defined by a slot-like recess A in the printed circuit board LP. The recess A has a substantially U-shaped contour, so that the actuating section BA is formed in the form of a tab or finger in the printed circuit board LP. Of course, the recess A can also have a different shape. For example, the recess A can be a V-shaped slot or any other slot, such as a simple straight slot, provided that this creates an area separated from the main section HA that is suitable for actuating the valve V. Furthermore, it is not necessary for the actuating section BA to be located inside the printed circuit board LP. For example, in other embodiments, the actuating section BA can also be formed as a projection of the printed circuit board LP.

[0026] The actuating section BA is connected to the main section HA of the printed circuit board LP via a deformation section VA. The deformation section VA has a lower stiffness than the main section HA and / or the actuating section BA and allows flexibility of the actuating section BA, i.e., movement of the actuating section BA relative to the main section HA. In other words, the deformation section VA is specifically designed to allow the actuating section BA to move smoothly relative to the main section HA.

[0027] To allow the actuating section BA to move relative to the main section HA, the deformation section VA has a stiffness-reduced zone Z, which permits a certain degree of flexibility or bendability of the printed circuit board (PCB) in the area of ​​the stiffness-reduced zone Z. For example, the stiffness-reduced zone can be made of a more flexible or bendable material than the PCB material of the actuating section BA and the main section HA. It is also conceivable that the stiffness-reduced zone can be created by using a plasticizer. Similarly, the stiffness-reduced zone can be created by material cutouts, for example, in the form of small bores or holes.

[0028] In the specific example of Fig. 1. The stiffness-weakened zone has a groove N or is designed as a groove N (see also Fig. 2 and Fig. 3) By providing the groove N between the actuating section BA and the main section HA of the printed circuit board LP, the stiffness of the deformation section VA is reduced, thereby increasing the mobility or flexibility of the deformation section VA and thus facilitating movement of the actuating section BA relative to the main section HA.

[0029] As further in Fig. As shown in Figure 1, the actuator unit AE has a shape memory alloy element (SMA element) SMA, which in the specific example of Fig. 1 is formed in the form of a wire. The shape memory alloy wire (SMA wire for short) SMA has a first end E1, which is electrically and mechanically connected to the main section HA, and a second end E2, which is electrically and mechanically connected to the actuating section BA. The electrical and mechanical connection between the ends E1, E2 and the main section HA or the actuating section BA is made, for example, via a crimp connection. Of course, other suitable connections between the SMA wire SMA and the main section HA or actuating section BA are also conceivable.

[0030] Although in the Fig. Figure 1 shows the shape memory alloy element SMA as an SMA wire, one end of which E1 is electrically connected to the main section HA, and the other end of which E2 is electrically and mechanically connected to the actuating section BA. In other embodiments, however, it is also conceivable that both the first end E1 and the second end E2 are electrically and mechanically connected to the main section HA, and that the shape memory alloy element SMA is, for example, designed as a loop that is coupled to the actuating section BA exclusively mechanically. In this embodiment, conductor tracks or electrical contacts in the area of ​​the actuating section BA can be omitted.

[0031] It was now on Fig. 2 referenced, which shows a schematic sectional view of a valve V with the actuator unit AE of Fig. 1 along line AA from Fig. 1 shows, where Fig. 2 shows the valve V in a closed state. The valve V can be used, for example, for a pneumatic adjustment device PV of a vehicle seat, as described in connection with Fig. 4 will be explained in more detail.

[0032] As in Fig. As can be seen in Figure 2, the valve V has a valve housing VG that defines a valve chamber or pressure chamber DK. The valve housing VG also has an opening O extending into the pressure chamber DK, which serves as the fluid connection FA for the valve V.

[0033] As in Fig. As can also be seen in Figure 2, the actuator unit AE is arranged inside the valve housing VG. The actuator unit AE is arranged in the valve housing VG such that the main section HA is essentially fixed to the valve housing VG. An end of the actuating section BA opposite the deformation section VA has a sealing element DE on its side facing the opening O, which is designed to seal the fluid connection FA.

[0034] On the side of the actuating section BA opposite the sealing element DE (i.e., on the side of the actuating section BA facing away from the opening O), a return element RE in the form of a spring is arranged. The spring is connected at one end to the valve housing VG and at the other end to the actuating section BA. The return element RE thus generates a preload force on the actuating section BA, so that the actuating section BA is biased in the direction of the fluid port FA.

[0035] If the shape memory alloy element SMA is no longer subjected to electrical energy, it returns to its original shape and length. The preload force of the restoring element RE can then move the actuating section BA towards the fluid port FA, so that the sealing element DE closes the fluid port FA. The movement of the actuating section BA is enabled by the deformation section VA, which has a lower stiffness than the actuating section BA and / or the main section HA. Because the deformation section VA has a stiffness-reduced zone Z with a groove N, the actuating section BA can be moved or pivoted easily relative to the main section HA.

[0036] To increase the mobility of the actuating section BA, the actuating section BA in the specific example of Fig. 2. Furthermore, the actuating section BA has a smaller thickness D1 than the main section HA, whose thickness is denoted by D2. By having a thickness D1 that is smaller than the thickness D2 of the main section, the flexibility of the actuating section BA is increased, or its stiffness is reduced, so that the actuating section BA can be moved more easily.

[0037] It was now on Fig. 3 referenced, which shows a schematic sectional view of valve V of Fig. 2 shows, with the valve V in Fig. 3 is shown in an open state.

[0038] The valve V is opened from the closed state ( Fig. 2) into the open state ( Fig. 3) is converted by applying electrical energy to the shape memory alloy element SMA. When electrical energy is supplied to the shape memory alloy element SMA, the SMA shortens. Because the shape memory alloy element SMA is designed as an SMA wire, one end E1 of which is mechanically connected to the main section HA and the other end E2 of which is mechanically connected to the actuating section BA, the actuating section BA moves against the preload force of the return element RE and thereby opens the fluid connection FA. The movement of the actuating section BA is in turn enabled by the deformation section VA, which has the stiffness-reduced zone Z with the groove N.

[0039] The in the Fig. 2 and Fig. The arrangement of the actuator unit AG shown in Figure 3 inside the valve housing VG makes it possible to create a valve V that is normally closed when the shape memory alloy element SMA is not subjected to electrical energy. Of course, it is also conceivable that the actuator unit AE is arranged in the valve V such that it can be used in a normally open (NO) valve.

[0040] As also in the Fig. 2 and Fig. As can be seen in Figure 3, the actuator unit AE has an end-position detection device ELD, which is designed to detect any movement of the actuating section BA exceeding a predetermined threshold. The end-position detection device ELD is, in this specific example, Fig. 2 and Fig. 3. The valve is designed such that, in the closed state of the valve V, i.e., in a state where the actuating section BA is in the non-displaced state relative to the main section HA, an electrical contact exists between the actuating section BA and the main section HA. If the shape memory alloy element SMA is now subjected to electrical energy and the resulting change in shape of the shape memory alloy element SMA causes the actuating section BA to deflect relative to the main section HA, then, if the movement of the actuating section BA relative to the main section HA exceeds a predetermined threshold, the contact between the actuating section BA and the main section HA is interrupted.The interruption of the contact can be used as a signal indicating that the actuating section BA is in a position corresponding to the maximum permissible deflection relative to the main section HA. The signal generated by the contact interruption can therefore be used as a protective signal, preventing the shape memory alloy element SMA from being subjected to electrical energy exceeding a predetermined threshold. In other words, interrupting the contact prevents overheating of the shape memory alloy element SMA and thus extends its service life.

[0041] However, it is also possible that the end position detection device ELD is designed in such a way that a contact between the actuating section BA and the main section HA is not closed when the actuating section BA is in a non-displaced state relative to the main section HA, and that a contact between the actuating section BA and the main section HA is only closed when the actuating section BA is in a position corresponding to a maximum permissible displacement relative to the main section HA.

[0042] It was now on Fig. 4 referred to, which shows a schematic representation of a pneumatic adjustment device PV of a vehicle seat FZS, which the valve V of Fig. 2 and Fig. 3.

[0043] The pneumatic adjustment device PV has a fluid chamber FK located below a seat mounting surface SAF of the vehicle seat FZS. By filling or emptying the fluid chamber FK, its size can be changed, thereby adjusting the contour of the seat mounting surface SAF in the area of ​​the fluid chamber FK. The valve V is fluidically connected to the fluid chamber FK via the fluid port FA, so that, for example, opening the fluid port FA allows fluid to flow from the pressure chamber DK of the valve V into the fluid chamber FK. The pneumatic adjustment device PV also has a fluid source FQ, which is fluidly connected to the valve V via a second fluid port (schematically represented as FA2), which has not yet been described.This allows the fluid supplied by the fluid source FQ, for example by means of a compressor (not shown), to flow into the valve V via the fluid connection FA2 and from there, controlled, to flow into the fluid chamber FK via the fluid connection FA.

[0044] Although in Fig. Not shown in Figure 4, the pneumatic adjusting device PV can have a second valve, identical in construction to valve V, which is fluidly controlled and connected to the fluid chamber FK, and fluidly uncontrolled and connected to the environment. By using such a second valve, the fluid chamber FK can be emptied in a controlled manner.

[0045] Of course, it is also possible that a first actuator unit AE and a second actuator unit AE can be arranged in a common valve housing VG, which (by means of appropriate connections) allow both filling and emptying of the fluid chamber FK.

[0046] Although the actuator unit AE has been described in connection with a valve used for a pneumatic adjustment device of a vehicle seat, it is also possible for the actuator unit AE to be used independently in a valve used for other purposes.

Claims

[1] Actuator unit (AE) for actuating a valve (V) for a pneumatic adjustment device (PV) of a vehicle seat (FZS), comprising: - a printed circuit board (PCB) with an actuating section (AC) for actuating the valve (V) and - a shape memory alloy element (SMA) coupled to the actuating section (BA) which, when electrical energy is supplied, is deformable such that the actuating section (BA) is moved to actuate the valve (V), wherein the actuating section (BA) is defined by a recess (A) in the printed circuit board (PCB). [2] Actuator unit (AE) according to claim 1, wherein the shape memory alloy element (SMA) is connected to the actuating section (BA) exclusively mechanically. [3] Actuator unit (AE) according to claim 1, wherein the shape memory alloy element (SMA) is electrically and mechanically connected to the actuating section (BA). [4] Actuator unit (AE) according to any of the preceding claims, wherein the printed circuit board (PCB) has a main section (HA) which is connected to the actuating section (BA) via a deformation section (VA) and the deformation section (VA) has a lower stiffness than the main section (HA) and / or the actuating section (BA). [5] Actuator unit (AE) according to claim 4, wherein the lower stiffness of the deformation section (VA) is achieved by the deformation section having a stiffness-weakened zone (Z). [6] Actuator unit (AE) according to claim 5, wherein the stiffness-weakened zone (Z) has a groove (N). [7] Actuator unit (AE) according to any one of claims 4 to 6, wherein the actuating section (BA) has a smaller thickness (D1) than the main section (HA). [8] Actuator unit (AE) according to any one of claims 4 to 7, wherein the shape memory alloy element (SMA) is a shape memory alloy wire, one end (E1) of which is connected to the main section (HA) and the other end (E2) of which is connected to the actuating section (BA). [9] Actuator unit (AE) according to any of the preceding claims further comprising: - an end position detection device (ELD) that detects movement of the actuating section (AC) beyond a predetermined threshold. [10] Valve (V) for a pneumatic adjustment device (PV) of a vehicle seat (FZS), comprising: - a valve body (VG) having a fluid port (FA), and - an actuator unit (AE) according to one of the preceding claims, wherein the actuating section (BA) is designed to open and close the fluid connection (FA). [11] Valve (V) according to claim 10, wherein the actuator unit (AE) is arranged inside the valve housing (VG) such that when electrical energy is supplied to the shape memory alloy element (SMA) the actuating section (BA) is moved to open the fluid port (FA). [12] Valve (V) according to claim 11, wherein the valve (V) has a return element (RE) configured to move the actuating section (BA) to close the fluid port (FA) when the supply of electrical energy to the shape memory alloy element (SMA) is terminated.

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