Drive device for controlling an actuating movement of a control element

Abstract

A drive device for controlling an actuating movement of a control element (12), in which at least one actuating element (18) made of a shape memory alloy is provided for controlling the actuating movement of the control element (12) in a first direction of movement, wherein a first driver (16) engaging thereon is provided for controlling the actuating movement of the control element (12) in a first direction of movement, on which driver the at least one first actuating element (18) made of a shape memory alloy engages to generate the actuating movement of the control element by the driver (16), and a return element (22) engaging the first driver (16), which returns the first driver (16) opposite to the first direction of movement, and wherein the driver (16) is decoupled from the control element (12) when returned opposite to the first direction of movement, wherein when the driver (16) is reset by means of the return element (22), the driver (16) can be released from an engagement element (24),so that the control element (12) remains in its set position.,

Description

[0001] The invention relates to a drive device for controlling an actuating movement of a control element, in which at least one actuating element made of a shape memory alloy is provided for controlling an actuating movement.

[0002] The use of an actuating element made of a shape memory alloy to control an actuating movement of a control element is generally known, for example, from DE 10 2010 020 514 A1. A return element, such as a return spring, is usually provided for a return movement of the control element in order to return the control element to its initial position after the actuating element made of a shape memory alloy has been energized. Such controls have the disadvantage that when the control element is transferred from an initial position to a control or switching position and the control element remains in the control or switching position, a continuous energization of the actuating element made of a shape memory alloy is necessary to maintain this control or switching position. In many applications, this is undesirable, especially since it also results in increased energy consumption.

[0003] DE 10 2012 208 423 A1 discloses a fast-return actuator. This actuator has a driver that can be controlled by an actuating element made of a shape memory alloy, as well as a component that can be controlled by the driver. This component engages via a shoulder with a corresponding shoulder on the driver, so that the component can be moved in a first direction of movement when the driver is controlled by the actuating element. At the end of this actuating movement, the driver comes into contact with a chamfered surface, so that the driver is released from the component and the two shoulders are decoupled from one another. This enables movement of the component opposite to the first direction of movement, which is controlled by a spring acting on the component and executes a fast return movement of the component.With this actuator, after the driver is decoupled from the component, the spring forces the component to return to its original position. The control or switching position of the component is maintained only as long as the driver is engaged with the component and the actuating element is simultaneously energized.

[0004] From EP 0 045 250 A1 an adjusting device with an adjusting element made of a shape memory alloy is known.

[0005] DE 10 2012 104 901 A1 discloses actuators for actuating a control element mounted in a force transmission member. This comprises an opening spring made of a shape memory alloy, which acts on the force transmission member in a first direction, with the spring force depending on the temperature of the opening spring.

[0006] US 2008 / 0307786 A1 discloses a multi-stable actuator comprising a movable part relative to a base part. This movable part is movable by adjusting elements made of a shape memory alloy that act in opposite directions when energized. The movable part, the adjusting elements, and the base part are integrally connected to one another.

[0007] The invention is based on the object of proposing a drive device for controlling an actuating movement of an actuating element, in which at least a reduction in energy consumption is possible.

[0008] This object is achieved by a drive device in which a first driver engaging thereon is provided to control the actuating movement of the control element in a first direction of movement, on which driver the at least one first actuating element made of a shape memory alloy engages to generate the actuating movement of the control element by the driver in the first direction of movement, and a return element engaging the first driver is provided, which returns the first driver opposite to the first direction of movement and is decoupled from the control element. As a result, a control current or energy consumption is only required for a short time to transfer the control element to a control or switching position.Due to the decoupling of the driver from the control element, which transmits the actuating movement to the actuating element but not the return movement, the driver can be returned to its original position without moving or resetting the control element from the switching or control position. The control element can remain in the control or switching position.

[0009] According to a preferred embodiment of the drive device, a second driver engaging the control element is provided to control an actuating movement of the control element in a second direction of movement, in particular opposite to the first direction of movement, on which driver at least one actuating element made of a shape memory alloy engages to generate the actuating movement of the control element by the second driver in the second direction of movement, and a return element engaging the second driver is provided, which resets the second driver opposite to the second direction of movement and decouples the second driver when returning opposite to the second direction of movement to the control element.By duplicating the control using a driver that can be decoupled from the control element in one direction of movement, a first and second direction of movement can be controlled, whereby the activation of the actuating element made of a shape memory alloy is no longer necessary to maintain the respective end position or switching or control position. If the two drivers are aligned oppositely with regard to their direction of movement, the control element can be guided from an initial position to a switching position by the first driver and then returned from the switching position to the initial position by the second driver. The drivers therefore only need to be activated, for example, energized, to carry out the actuating movement of the control element.Since the first and second drivers are each decoupled from the control element, independent control of the actuating movement of the first and second drivers is also possible.

[0010] Furthermore, the first and second drivers are preferably controllable independently of one another. This also achieves decoupling in the control of the respective drivers. The respective actuating elements only need to apply the actuating force required to move the control element from a first to a second position, without operating against the actuating force of the other driver.

[0011] Preferably, the first and second drivers are mounted on a common axis of rotation. This allows for a structural simplification.

[0012] Preferably, the control element and the first and second drivers are mounted on a common axis of rotation, but decoupled from each other. This allows for a particularly compact design of such a drive device as well as independence in the control of the drivers and the control of the direction of rotation of the control element.

[0013] The control element has an engagement element for each driver, which the driver engages to control the adjustment movement in the respective direction of movement. When the driver is reset using the reset element, the driver can detach from the engagement element, so that the control element remains in its set position.

[0014] The driver is preferably designed as a lever or an angled lever, with the shape memory alloy adjusting element engaging one lever arm and the return element engaging the opposite lever arm. The lever arms can be designed accordingly depending on the forces to be applied. At the same time, this allows for simple force ratios to be created.

[0015] The first and second drivers are preferably mirror images of each other and are provided on the common axis of rotation.

[0016] This allows for duplication of the control element to be controlled with respect to the driver, the adjusting element and the return element, whereby the mirror-image arrangement of the two drivers allows for opposite directions of movement of the control element to be controlled.

[0017] A first embodiment of the drive device provides that the two drivers are assigned to one side of the control element.

[0018] This allows, for example, a control surface to be formed on the opposite side of the control element. Alternatively, a driver can be provided on each side of the control element. This enables a symmetrical design.

[0019] Furthermore, a locking element or a toothing is preferably provided on the control element, on which a complementary component engages. Such a locking mechanism allows adjustable switching positions to be set within a travel range of the control element. For example, this allows not only an initial position and a switching position or end position of the control element to be controlled, but also switching positions in between. Furthermore, the locking mechanism can be used to set a travel range that can be increased or decreased in steps or in increments, so that a step-by-step adjustment movement of the control element can be controlled. This applies to both the first and the second direction of movement, which is preferably opposite to the first direction of movement.

[0020] The control element preferably has at least one switching or control surface. This switching or control surface can close or open a passage opening. Furthermore, electrical contacts or switches can be actuated, or locks can be released or closed. Furthermore, the control element can comprise a control piston, a control valve, or a control opening to regulate the flow rate of gas or liquid media.

[0021] The return element is advantageously designed as an elastically deformable element that, after the driver is deflected by the actuating element, performs a return movement to return the driver to its original position. The return element is advantageously designed as a return spring.

[0022] The actuator, formed as a shape memory alloy wire, extends from a connection point to the driver. In particular, it is provided that the actuator extends from a connection point over the driver back to the connection point, thus providing a simple electrical connection for the actuator.

[0023] The control element, the drivers, and the at least one actuating element and return element engaging thereon are preferably arranged in a housing and designed as a built-in module. This allows for a wide range of possible applications, with only a coupling between the control element and the element to be actuated being required to control the actuating movement. Preferably, the housing has an opening through which the control element is at least partially guided or adjacent to it, or a coupling element for fastening to the control element can be guided.

[0024] When designing a built-in module, it can preferably be provided that the connection or contact points of the actuating elements can be led out of the housing by means of a sealed feedthrough, in particular a glass feedthrough. This also allows such a built-in module to be used in applications in which the medium to be controlled flows at least partially into the housing. In such a case, the actuating element can preferably be provided with a temperature-insulating coating or sleeve, in particular a Teflon sleeve, at least in the area in which it is surrounded by the inflowing medium.

[0025] The control element preferably has a control surface for regulating a gaseous or liquid mass flow, through which at least one opening of a connection can be controlled. The opening can be controlled digitally, i.e., it is opened or closed. Proportional control can also be provided, i.e., the opening is gradually opened or closed with an increasing actuating movement of the control element. Depending on the geometry of the opening, a mass flow can also increase or decrease with increasing actuating movement.

[0026] The control of such a drive device for an actuating movement of the control element is preferably achieved by a constant current supply to one of the two actuating elements in order to actuate the control element in one or the other direction of movement. This can enable a targeted actuating movement to actuate another movement element coupled to the control element. Likewise, in the case of a valve, a targeted control of a mass flow can be achieved by opening and closing at least one through-bore.

[0027] Alternatively, the actuating movement of the control element can be achieved by pulse-width modulation. The actuation or current supply to the actuating element is thus not constant; instead, a current is applied over a predetermined cycle time and then reset to zero. This type of control using pulse-width modulation has the advantage of reducing overall energy consumption, which, for example, helps reduce fuel consumption when using such a drive system in a motor vehicle.

[0028] The control device preferably has at least one sensor element for detecting a switching position or actuating movement of the control element, so that upon reaching a predetermined switching position or actuating movement and / or an end position, a signal is output to the control device to stop the constant current supply, on the one hand, or the actuation via pulse width modulation, on the other. The sensor element can be a Hall sensor, for example. Other sensors, proximity switches, or the like that detect a change in distance or an actuating movement of the control element can also be used.

[0029] A further alternative embodiment of the sensor element is provided in that a change in resistance of the shape memory alloy wire is detected during the control of the actuating movement and the switching position can thus be determined.

[0030] The invention, as well as further advantageous embodiments and developments thereof, are described and explained in more detail below with reference to the examples shown in the drawings. The features shown in the description and the drawings can be used individually or in any combination according to the invention. They show: Fig. 1a and Fig. 1b schematic views of the drive device according to the invention, Fig. 2 a schematic view of the drive device according to Fig. 1 after a control movement of the control element, Fig. 3 a schematic view of the drive device according to Fig. 1 after completion of the control of the control element in one direction of movement, Fig. 4 a schematic view of a grid for the stepwise adjustment movement of the control element according to Fig. 1, Fig. 5 a schematic view of a built-in module with the drive device according to Fig. 1, Fig. 6 a schematic side view of the installation module according to Fig. 5, Fig. 7 a schematic sectional view of a switching valve for controlling a mass flow with the installation module according to the Fig. 5 and Fig. 6, Fig. 8 a schematically simplified representation of a control element for assuming two switching positions, Fig. 9 a schematic view of an alternative application example of the control element according to Fig. 8, Fig. 10a, Fig. 10b and Fig. 10c schematically simplified views of the control element according to Fig. 1 in three switching positions, Fig. 11 a schematic view of an alternative embodiment of the control element to Fig. 10, Fig. 12 a schematic view of another alternative embodiment of the control element to Fig. 11 and Fig. 13a and Fig. 13b schematic views of an alternative embodiment to the Fig. 10a and Fig. 10b.

[0031] In Fig. 1a is a schematic view from the front and in Fig. 1b shows a schematic side view of a drive device 11. This drive device 11 comprises a control element 12, which is rotatably mounted on a rotational axis 14 in a housing, housing section, or frame (not shown in detail). Associated with the control element 12 is a first driver 16, which is also rotatably mounted on a rotational axis. Preferably, the driver 16 is also mounted on the rotational axis 14. The driver 16 is designed as a lever, in particular an angled lever. An actuating element 18 made of a shape memory alloy engages a lever arm 17. Preferably, a wire made of a shape memory alloy is provided. This wire is attached at an opposite fixed end to a housing, object, or the like and has a connection contact 19.Preferably, both ends of the actuating element 18 are provided at a fixed connection area, so that easy contact is possible by means of the connecting contacts 19 arranged thereon. A controller (not shown in detail) can be connected to the connecting contacts 19 in order to actuate, in particular to supply current to, the respective actuating elements 18, 27. Alternatively, the actuating element 18 can also be provided only between the driver 16, in particular lever arm 17, and a spatially fixed or housing-fixed section. Opposite the lever arm 17, a second lever arm 21 is provided, which is aligned, for example, at an angle to the first lever arm 17. Alternatively, the first and second lever arms 17, 21 can also be designed as a straight rod or rod element. A return element 22, which is designed as an elastically deformable actuating element, in particular a return spring, engages the second lever 21.The return element 22 is fastened with its end opposite the lever 21 to a housing, housing section or frame not shown in detail.

[0032] An engagement element 24, in particular a pin, web or projection, is provided on the control element 12, against which the driver 16, in particular the second lever arm 21 of the driver 16, rests. By energizing the actuating element 18, an actuating movement of the driver 16 can be controlled counterclockwise, wherein the control element 12 is also controlled counterclockwise with an actuating movement in a first direction of movement. This is shown in Fig. 2. Depending on the current supply to the actuating element 18, the rotary movement of the driver 16 and thus the rotation or actuating movement of the control element 12 is controlled. After a predetermined position of the control element 12 has been reached ( Fig. 2), the actuator 18 is de-energized and the driver 16 is returned to its initial position by the return element 22. This position is shown in Fig. 3. This return of the driver 16 to the starting position and dependent on the control element 12 occurs due to the decoupling of the driver 16 from the control element 12. This decoupling is provided, for example, by the engagement element 24 only abutting the driver 16 as well as the rotational decoupling on the rotation axis 14. The control element 12 thus maintains its control position, as shown in the Fig. 2 and Fig. 3, whereas the driver 16 is returned to its initial position.

[0033] The drive device 11 described above can only be actively controlled in one direction of movement and its resetting can take place independently of the control of the actuating element 18.

[0034] In the Fig. 1a and Fig. In the drive device 11 shown in Figure 1b, the above-described arrangement of the driver 16, the actuating element 18 engaging thereon, and the return element 22 is also provided on an opposite side of the control element 12, so that a second driver 26, a second actuating element 27 made of a shape memory alloy, a second return element 28, and a further actuating element 29 are provided on the rotational axis 14. The second driver 26 is aligned in the same way as the first driver 16 with respect to the opposite side of the control element 12, i.e., the first driver 16 and the second driver 26 are aligned point-symmetrically to the rotational axis 14, so that the first driver 16 causes an actuating movement of the control element 12 in the counterclockwise direction, and the second driver 26 controls an actuating movement of the control element 12 in a second clockwise direction.

[0035] Such a drive device 11 enables that starting from a control position of the control element 12 according to Fig. 3 by controlling the second driver 26, the control element 12 returns to the starting position according to Fig. 1a, whereby the actuating elements 18, 27 can be controlled independently of one another and the drivers 16, 26 also generate the respective actuating movement decoupled from one another and decoupled from the control element 12.

[0036] An alternative embodiment of the drive device 11 (not shown in detail) provides that the first and second drivers 16, 26 are arranged adjacent to one another and on the same side of the control element 12. If a rotational movement is to be controlled which is greater than the distance between the two engagement elements 24, 29, the drivers 16, 26 are positioned at different distances from the control element on the rotation axis 14, so that one of the two engagement elements 24, 29 can be overrun by one of the two drivers 16, 26.

[0037] By such a Fig. 1a and Fig. In the drive device 11 shown in Figure 1b, the control element 12 can be positioned in two end positions. These can be assumed, for example, in a self-locking manner due to friction with the rotation axis 14.

[0038] The above-described embodiment according to the Fig. 1a and Fig. 1b is preferably designed symmetrically, meaning that identical actuating elements 18, 27 are used in both directions of movement to control identical actuating movements. For this purpose, the same actuating elements 18, 27 are preferably provided with the same trigger temperatures.

[0039] According to an alternative embodiment, an actuating element 18 can engage the driver 16, which has a higher triggering temperature, for example, 80 - 90 °C, than the second actuating element 27 acting on the driver 26, whose triggering temperature is, for example, 30 - 40 °C. If, for example, an ambient temperature is above this triggering temperature, an actuating movement of the second driver 26 occurs, whereby the control element 12 is moved clockwise, i.e., the second actuating element 27 is thermally controlled. In order to reset the control element 12, the first actuating element 18 can be electrically controlled in order to return it to predetermined conditions. Advantageously, the actuating element 18 is designed with an actuating force such that the second actuating element 27, which may still be active, is also forcibly returned.

[0040] In Fig. 4 is a schematic view of the control element 12 according to the drive device 11 in Fig. 1a, which has, for example, a toothing 32 on one end face 31, which engages a locking element 33 that is stationary or provided on a housing. Such a locking or toothing enables a step-by-step adjustment of the control element 12 in one or the other direction of movement, as well as, through the locking, a temporary positioning and arrangement of the control element 12 in the set angular position. It is understood that the toothing and the locking element can also be arranged interchangeably. Likewise, the locking can also be provided on a side surface of the control element 12.

[0041] In Fig. 5 is a schematic view from the front and in Fig. 6 shows a schematic side view of a built-in module 35 with the drive device 11. This built-in module 35 comprises a housing 36 in which the rotational axis 14 is anchored. Adjacent to this, a wall or a wall section 37 is provided in the housing 36, on which, for example, the return elements 22, 28 engage. These can also engage a side wall 38 of the housing 36. The actuating elements 18, 27 are led out opposite a side wall 38, in particular a bottom of the housing 36, so that the connection contacts 19 lie outside the housing 36. A controller 39 can be connected to the connection contacts 19. The actuating elements 18, 27 can be led out of the housing 36 by means of seals or feedthroughs.

[0042] According to this embodiment, the control element 12 is L-shaped when viewed from the side and comprises a connecting section 41, which protrudes, for example, through an opening 42 from a side wall 38 of the housing 36. Alternatively, the connecting section 41 can also remain within the housing 36 and a separate connecting piece or coupling piece can be attached thereto. Such a built-in module 35 protects the drive device 11, in particular the arrangement of the drivers 16, 26 on the rotation axis 14, as well as the actuating elements 18, 27 for controlling the control element 12.

[0043] In Fig. 7 is an application example for such a built-in module 35 according to the Fig. 5 and Fig. 6. This installation module 35 is inserted, for example, into a valve housing 45 to provide a switching valve 46 for controlling a mass flow for a fluid flowing through the valve housing 45. For example, the connection section 41 can be designed as a valve element or valve closing member, which is directly assigned to an inlet opening 48, in particular a valve seat 49 of the inlet opening 48, on the valve housing 45. A flow opening 51 is provided on the housing 36 of the installation module 35, which opens into an outlet opening 52 of the valve housing 45. The connection contacts 19 of the installation module 35 are surrounded by a sealing feedthrough 54, in particular a glass feedthrough, to enable electrical control.

[0044] In this application example, the control element 12 is driven in rotation about the rotation axis 14, thereby progressively opening and closing the valve seat 49. The control element 12 is designed as a type of slide that rests on the valve seat 49 so that it can be moved.

[0045] If the control element 12 has a grid according to Fig. 4 is provided, predetermined opening positions can be assumed, whereby a mass flow defined by the opening position can flow through the valve housing 45.

[0046] The actuating movement of the control element 12 for opening and closing the inlet opening 48 or the outlet opening 52 can also be achieved by rotating the rotational axis 14 by 90°. This is shown schematically in Fig. 8. For example, a corner region 56 of the control element 12 can be designed as a valve closing member which closes a valve seat 49 of an inlet opening 48.

[0047] In the embodiment according to Fig. Figure 8 shows an embodiment in which the control element 12, in an initial or zero position, opens both a right and a left through-opening 48, 52. By moving the control element 12 counterclockwise, the left through-opening 52 can be closed. The same applies to a clockwise control movement. In this case, the right through-opening 48 can be closed, while the opposite through-opening 52 remains open.

[0048] In Fig. 9 is an alternative embodiment to Fig. 8. Instead of opening and closing through-openings 48, 52 to control a flowing fluid, the corner region 56 of the control element 12 can also be used to control switching contacts 58, in particular electrical switching contacts. Fig. The embodiment shown in Figure 9 can be mounted on one side or - as Fig. 9 shows - can also be provided on both sides. Such an arrangement also enables a position report or a monitoring function regarding the controlled end position or end positions of the control element 12 of the drive device 11.

[0049] In the Fig. 10a and Fig. 10b shows a further alternative application of the drive device 11 in a simplified schematic representation. In this embodiment, a side surface of the control element 12 is provided as a control or switching surface. A first and a second aperture 61, 62 are assigned to this control surface. Fig. In the position shown in Figure 10a, a so-called zero position or initial position, both apertures 61, 62 are closed. By rotating the control element 12 in one direction of movement, for example clockwise, aperture 61 remains closed, whereas aperture 62 is opened, allowing a fluid to flow through aperture 62 ( Fig. 10b). With a further rotation in the same direction, both apertures 61, 62 can be opened ( Fig. 10c). If an actuating movement of an actuating element 12 in the opposite direction, i.e. counterclockwise, from the position according to Fig. 10c, the apertures 61 and 62 can be closed gradually and with a further rotational movement of the adjusting element 12 only the aperture 61 can be opened, whereas the aperture 62 is closed.

[0050] In Fig. Figure 11 shows an alternative embodiment of the control element 12 with respect to a first and a second orifice 61, 62. The control element 12 has a recess 64 or cutout through which the orifice 61 is opened in a zero position and the orifice 62 is closed. Such an arrangement can be used, for example, in a control valve whose initial position or zero position is open and is referred to as a NO (Normally Open) switching valve. By rotating the control element 12 clockwise, both orifices can initially be closed or, according to an alternative embodiment, only the orifice 61 can be closed and the orifice 62 can be opened. By rotating the control element 12 counterclockwise, both orifices 61, 62 can initially be opened or only the orifice 61 can be closed and the orifice 62 can be opened.

[0051] When used in switching valves for air conditioning systems, this embodiment can have the advantage that the control element 12 remains controllable, even when active control of the control element 18, 27 is no longer possible due to existing ambient temperatures that are higher than the trigger temperatures of the control element 18, 27. However, as soon as an air conditioning compressor is started in an air conditioning circuit due to the air conditioning system or the vehicle engine being switched on, coolant flows through the orifice 61, so that this coolant also reaches the control elements 18, 27 and cools them, so that these control elements 18, 27 are cooled down to a temperature that is below the trigger temperature, thus again enabling active control of the control element 12.

[0052] In Fig. 12 is an alternative embodiment to Fig. 11. This embodiment differs in that a third aperture 63 is provided in addition to the apertures 61, 62. The control element 12 can be rotated clockwise and counterclockwise, so that one of the three apertures 61, 62, 63 is always partially or fully open.

[0053] In the Fig. 13a and Fig. 13b, the control element 12 is shown as a slider with respect to an alternative design of the aperture 61. Instead of a round bore or a passage, the aperture 61 can also be designed as a slot-shaped recess. Fig. 13a, the aperture 61 is closed by the control element 12. By increasing the rotational movement, for example counterclockwise, the aperture 61 can be gradually opened, as can be seen from Fig.13b. With a constant cross-section of the orifice 61, a proportional increase in the mass flow can thus be controlled with increasing opening angle of the control element 12 to the orifice 61.

[0054] If, for example, a corner or edge area of the orifice plate 61 is enlarged and the enlarged area lies in one direction of movement at the end of an actuating movement of the control element 12, a discontinuous increase in the mass flow can be controlled. If the orifice plate 61 has a large opening cross-section at the beginning of the actuating movement, which tapers towards the end of the actuating movement, a large mass flow can initially be released, which increases discontinuously with the increasing actuating movement of the control element 12. The geometry of such an elongated orifice plate 61 can thus determine the increase and / or decrease or the change in the flow rate of a mass flow.

Claims

[1] Drive device for controlling an actuating movement of a control element (12), in which at least one actuating element (18) made of a shape memory alloy is provided for controlling the actuating movement of the control element (12) in a first direction of movement, wherein a first driver (16) engaging thereon is provided for controlling the actuating movement of the control element (12) in a first direction of movement, on which driver the at least one first actuating element (18) made of a shape memory alloy engages to generate the actuating movement of the control element by the driver (16), and a return element (22) engaging the first driver (16), which returns the first driver (16) opposite to the first direction of movement, and wherein the driver (16) is decoupled from the control element (12) when returned opposite to the first direction of movement, wherein when the driver (16) is reset by means of the return element (22), the driver (16) can be released from an engagement element (24),so that the control element (12) remains in its set position., [2] Drive device according to claim 1, characterized byin that, in order to control an actuating movement of the control element (12) in a second direction of movement, which is preferably opposite to the first direction of movement, a second driver (26) engaging the control element (12) is provided, on which a second actuating element (27) made of a shape memory alloy engages in order to generate the actuating movement of the control element (12) by means of the driver (26), and a return element (28) engaging the second driver (26) which returns the second driver (26) opposite to the second direction of movement, and in that the second return element (26) is decoupled from the control element (12) when returned opposite to the second direction of movement, and preferably when the driver (26) is reset by means of the return element (28), the driver (26) can detach from an actuating element (29), so that the control element (12) remains in its set position. [3] Drive device according to claim 1 or 2, characterized by that the first and second drivers (16, 26) can be controlled independently of one another. [4] Drive device according to one of the preceding claims, characterized by that the first and second drivers (16, 26) are mounted in a common axis of rotation (14). [5] Drive device according to one of the preceding claims, characterized by that the control element (12) and the first and second drivers (16, 26) are mounted in a common axis of rotation (14), but decoupled from one another. [6] Drive device according to one of the preceding claims, characterized by that the control element (12) has the respective engagement element (24, 29) for the driver (16, 26), on which the respective driver (16, 26) engages to control the adjusting movement in the respective direction of movement. [7] Drive device according to one of the preceding claims, characterized bythat the drivers (16, 26) are designed as a lever or angled lever, on one lever arm (17) of which the respective adjusting element (18, 27) acts and on the opposite lever arm (21) the respective return element (22, 28) acts. [8] Drive device according to one of the preceding claims, characterized by that the first and second drivers (16, 26) are arranged mirror-inverted to one another on the common axis of rotation (14). [9] Drive device according to one of the preceding claims, characterized by that the drivers (16, 26) are assigned to one side of the control element or that a driver (16, 26) is arranged on each side of the control element (12). [10] Drive device according to one of the preceding claims, characterized bythat a locking element (33) or a toothing (32) is provided on the control element (12), on which a complementary component engages and by means of the locking adjustable switching positions can be set within an adjustment path of the control element (12). [11] Drive device according to one of the preceding claims, characterized by that the control element (12) has at least one switching or control surface, a control piston, a control valve or a control opening. [12] Drive device according to one of the preceding claims, characterized by that the return element (22, 28) is designed as an elastically deformable element, in particular as a return spring. [13] Drive device according to one of the preceding claims, characterized bythat the adjusting element (18, 27) is designed as a shape memory alloy wire which extends from a connection point to the driver (16, 26) and preferably back to the connection point. [14] Drive device according to one of the preceding claims, characterized by that the control element (12), the drivers (16, 26) and the at least one actuating element (18, 27) and return element (22, 28) arranged thereon are arranged in a housing (36) and are designed as a built-in module (35) in which at least one opening (42) is provided to which the control element (12) is assigned. [15] Drive device according to claim 14, characterized by that the connection contacts (19) of the adjusting elements (18, 27) are led out of the housing (36) by means of a sealing leadthrough, in particular a glass leadthrough, and / or that the adjusting elements (18, 27) are surrounded by a temperature-insulating coating or a sleeve. [16] Drive device according to one of the preceding claims, characterized by that the control element (12) is provided for regulating a gaseous or liquid mass flow and has a control surface by means of which at least one aperture (61, 62, 63) can be controlled to open or close. [17] Drive device according to one of the preceding claims, characterized by that a constant current supply to the first or second actuating element (18, 27) is provided to control an actuating movement of the control element (12). [18] Drive device according to one of claims 1 to 16, characterized by that a pulse width modulation is provided to control an actuating movement of the control element (12). [19] Drive device according to one of claims 17 or 18, characterized byin that a sensor element is provided for detecting a switching position or actuating movement of the control element (12), which sensor element outputs a control signal to the controller for switching off the constant current supply or the pulse width modulation when the switching position or predetermined actuating movement is reached, and the sensor element is preferably designed as a Hall sensor or a measuring device for detecting the resistance in the actuating element (18, 27).

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