ACTUATOR ARRANGEMENT AND OPERATING PROCEDURES

Description

[0001] The invention relates to an actuator arrangement and a method for operating an actuator arrangement. background

[0002] Magnetic shape memory alloys (MSMA) are special shape memory alloys that exhibit a magnetic shape memory effect in addition to the thermal shape memory effect. In this case, a change in the magnetic orientation of the magnetic unit cells of the shape memory alloy is accompanied by a deformation that results in a change in length (considered in one spatial direction).

[0003] Reorientation can be caused by external forces through compression or elongation. In this process, the material exhibits internal friction, which necessitates overcoming a force or stress threshold for reorientation. This phenomenon is also known as "twin stress." In addition to this twin stress, MSMAs also exhibit the eponymous magnetic shape memory effect. A sufficiently strong magnetic field induces a contraction (tension) in the field direction and, correspondingly, an elongation (compression) perpendicular to it, whereby both forces can be utilized.

[0004] In contrast to purely thermal shape memory alloys, MSMAs have significantly faster response times (a few milliseconds compared to several seconds) for the same stroke. A considerably higher stroke is achievable compared to piezoelectric materials. With suitable data analysis, self-sensing can be used to reduce sensor costs.

[0005] Due to their inherent twin stress, magnetic shape memory alloys are suitable for linear actuators that can maintain a set position without an external power supply. This is particularly relevant for applications with specific safety requirements in the event of a power failure. The technology combines high holding force, similar to that achieved with self-locking actuators, with the high dynamics of electrodynamic actuators. These characteristics are advantageous for various positioning devices in automation and automotive engineering, such as grippers in robotics, as well as valves in pneumatic and hydraulic systems.

[0006] Known MSMA actuators typically operate as pure push or pull actuators against a restoring force. This restoring force must exceed the material's inherent twin stresses so that the actuator can be deformed back to its original position without excitation. Such an actuator design is known from document DE 10 2005 038 891 A1. In such a configuration, the twin stress is considered a pure loss. To maintain a position outside the rest position, a magnetic field must be continuously applied. Therefore, the alloys and the actuators manufactured from them (usually in the form of sticks) are optimized for the lowest possible twin stresses.

[0007] In contrast, multistable concepts explicitly utilize the twin voltage for a passive holding force in more than one position. According to one concept, only this holding force is used, not the magnetic shape memory effect. For example, actuation is achieved by a moving-coil actuator, and an MSMA element only provides a passive holding force. This passive force must then be overcome with each actuation.

[0008] Another concept utilizes the magnetic shape memory effect in one direction and provides for reset by applying a mechanical force. By combining two such actuators, a push-push actuator can be constructed, in which two MSMA actuators are arranged opposite each other with opposing actuation directions. When one MSMA element is energized, a central tap is moved in the actuation direction of that MSMA element. When the other MSMA element is energized, the tap moves in the opposite direction. In this configuration, one MSMA element is actively used at any given time, while the twin voltage of the other MSMA element must be overcome passively by the force applied by the active MSMA element. For such a setup, independent excitation systems are required for the MSMA elements, of which only one is in use at any given time.

[0009] Finally, there are concepts that utilize both the holding force and the magnetic shape memory effect in both directions. In these cases, perpendicular fields must be imprinted on an MSMA element to enable deformation in both directions. Such a concept combines the multistable holding force with the actuator's use of the entire material. Designing the excitation system for such actuators is complex. For example, independent coils or coil sets can be provided for the excitation directions, with only one coil set being actively used at any given time.

[0010] Document US 10,581,345 B2 discloses a concept for operating a four-coil MSMA actuator. In this design, the four coils form two groups of two coils connected in series. The groups are arranged in a crisscross pattern around the MSMA element. Flux guide elements are designed such that, through the superposition of the generated magnetic fields, with the same current direction in the two groups, the MSMA element is permeated by a magnetic flux in a first direction, and with opposite current directions in the two groups, the MSMA element is permeated by a magnetic flux in a second direction, the second direction being perpendicular to the first.

[0011] Document US 2021 / 082604 A1 describes a magnetic field actuation system that can use one or more permanent magnets to induce a contracted region within a medium-silicon modulator (MSM) element while the system is de-energized. The contracted region can result from a vertical component of a magnetic field associated with one or more permanent magnets. The position of the contracted region can be shifted by energizing one or more electromagnets along the MSM element. The power of the electromagnets can be continuously varied to cause a uniform oscillation of the vertical component of the magnetic field, which can result in the contracted region moving continuously from side to side.

[0012] Document US 2016 / 087553 A1 discloses an actuating device comprising a magnetic shape memory element (MSM element) configured to contract locally in a section of the MSM element in response to a local action from a magnetic field distribution component that is substantially perpendicular to a longitudinal axis of the MSM element. The device may also include a plurality of conductive coils laterally offset from the MSM element. The central axes of each conductive coil in the plurality of conductive coils may be substantially parallel to a longitudinal axis of the MSM element.

[0013] Document DE 691 29 687 T2 relates to a device for generating a magnetic field for imaging using magnetic resonance. Summary

[0014] The object of the invention is to specify improved technologies for actuator arrangements with magnetic shape memory alloys, which in particular enable more efficient and / or targeted flux guidance.

[0015] To solve the problem, an actuator arrangement according to independent claim 1 and a method for operating an actuator arrangement are provided. Embodiments are specified in dependent claims in the attached set of claims.

[0016] According to one aspect, an actuator arrangement is created, comprising an actuator element, a first flux-generating device for generating a magnetic flux, a second flux-generating device for generating a magnetic flux, a control device, and a pole shoe element. The actuator element comprises a magnetic shape-memory alloy. A region of the actuator element has a first length in a first direction when the region is penetrated by a magnetic field in the first direction, and a second length in the first direction that differs from the first length when the region is penetrated by a magnetic field in a second direction, which is perpendicular to the first direction.The control device is configured to control the first flux-generating device and / or the second flux-generating device according to a first operating state and a second operating state, such that in the first operating state the actuator element is penetrated by a first magnetic flux in the first direction, and in the second operating state the actuator element is penetrated by a second magnetic flux in the second direction. The pole shoe element is configured to conduct the first magnetic flux in the first direction through the actuator element or is configured to conduct the second magnetic flux in the second direction through the actuator element. The pole shoe element is provided as a magnetically anisotropic pole shoe element.

[0017] Furthermore, a method for operating an actuator arrangement is provided. The method comprises the steps of providing the actuator arrangement according to the disclosure, controlling the first flux-generating device and / or the second flux-generating device to generate the first magnetic flux passing through the actuator element in the first direction, such that the actuator element assumes a first shape, and controlling the first flux-generating device and / or the second flux-generating device to generate the second magnetic flux passing through the actuator element in the second direction, such that the actuator element assumes a second shape that differs from the first shape.

[0018] A magnetically anisotropic pole shoe element as defined in the disclosure exhibits a higher magnetic resistance in one direction than in another. In particular, a pole shoe element is magnetically anisotropic if its (geometry-independent) homogenized initial permeability is at least 250 times greater in one direction than in the other, where the homogenized initial permeability is the mean relative permeability (or permeability number) of the pole shoe element in the relevant direction at low flux densities, i.e., without saturation. As detailed below, the pole shoe element can be formed with a laminate, in which case the homogenized initial permeability of the pole shoe element in the relevant direction is determined for a series or parallel connection of the individual materials.By using a magnetically anisotropic pole shoe element, magnetic flux through the pole shoe element in an undesired direction may be reduced or prevented. Specifically, a magnetically anisotropic pole shoe element configured to conduct the first magnetic flux through the actuator element in the first direction may exhibit lower magnetic resistance in the first direction than in the second direction. Similarly, a magnetically anisotropic pole shoe element configured to conduct the second magnetic flux through the actuator element in the second direction may exhibit lower magnetic resistance in the second direction than in the first. In this case, magnetic flux bypassing the actuator element through the pole shoe element in the direction of higher magnetic resistance of the pole shoe element may be reduced or prevented.

[0019] The pole shoe element can be formed with a laminate consisting of an arrangement of several layers, where the several layers comprise first layers of a first material and second layers of a second material. In this arrangement of several layers, first and second layers are alternately stacked on top of each other, with the first material having a first permeability (also called relative permeability) and the second material having a second permeability that differs from the first.This allows the pole shoe element to exhibit a lower magnetic resistance in the direction of the layers than perpendicular to the direction of the layers, since the magnetic flux in the direction of the layers can propagate unimpeded through the layers with the higher permeability, while the magnetic flux perpendicular to the direction of the layers must pass through the layers with the lower permeability. The material of the first and second layers with the lower permeability can be non-magnetic. For example, the pole shoe element can be formed with a laminate of soft iron and epoxy resin layers.

[0020] The layers in the laminate can be bonded together, as is known from the prior art in various designs for laminates as such, for example by means of an adhesive bond or thermal bonding techniques.

[0021] In an alternative embodiment, the layers with the lower permeability in the laminate can be formed by air, another gas or gas mixture, or by a vacuum. In this case, the layers are not bonded together, and the laminate of the pole shoe element can, in particular, be made of a material with a high permeability, which is formed with slots and / or other recesses.

[0022] The pole shoe element can be made of a magnetically anisotropic material. In this case, the pole shoe element comprises at least one material that is intrinsically magnetically anisotropic, meaning it has a different magnetic permeability in one direction than in another. The magnetic anisotropy of the pole shoe element can be achieved solely or substantially through the use of a magnetically anisotropic material, particularly if the material used exhibits a pronounced magnetic anisotropy. A pronounced magnetic anisotropy of a material is particularly evident if the permeability of the material in one direction is at least 20 times greater than in the other direction.A magnetically anisotropic pole shoe element with a homogenized initial permeability at least 250 times greater in one direction than in the other can be achieved by a correspondingly large factor between the direction-dependent permeability values ​​of the magnetically anisotropic material, or alternatively by additional measures, such as a suitable geometry of the pole shoe element and / or by forming the pole shoe element with a laminate. In particular, when forming the pole shoe element with a laminate, the first material and / or the second material can be magnetically anisotropic. In this way, the intrinsic magnetic anisotropy of the first and / or the second material can be enhanced for the pole shoe element as a whole by the arrangement of several layers in the laminate.

[0023] A flux guide element, formed with a wedge shape, is provided and associated with the pole shoe element. The flux guide element is arranged such that the magnetic resistance of the pole shoe and flux guide element assembly is higher in the direction of lower magnetic resistance at the edges of the pole shoe element than in the central region. The edges are defined as regions located opposite the pole shoe element along the direction of higher magnetic resistance. The central region lies between the edges along the direction of higher magnetic resistance.The wedge shape of the flow guide element can be designed and the flow guide element can be arranged such that a larger air gap is formed between the pole shoe element and the flow guide element in the edge areas than in the central area, wherein the flow guide element in the central area can be arranged with an air gap to the pole shoe element or directly adjacent to or connected with the pole shoe element.

[0024] The actuator arrangement can be formed with two pole shoe elements, which are arranged along the first direction on opposite sides of the actuator element and each configured to conduct the first magnetic flux in the first direction through the actuator element, wherein the two pole shoe elements are provided as magnetically anisotropic pole shoe elements. For this purpose, the two pole shoe elements can, in particular, be arranged such that they exhibit a lower magnetic resistance in the first direction than in the second direction. In this way, effective conduction of the magnetic flux in the first direction through the actuator element can be ensured by means of the two pole shoe elements in the first operating state, while in the second operating state, magnetic flux through the two pole shoe elements in the second direction is reduced or prevented, bypassing the actuator element.

[0025] Two additional pole shoe elements can be provided, arranged along the second direction on opposite sides of the actuator element and each configured to guide the second magnetic flux in the second direction through the actuator element. In this way, effective guidance of the magnetic flux in the second direction through the actuator element can be ensured by means of these two additional pole shoe elements in the second operating state.

[0026] The two additional pole shoe elements can be provided as magnetically anisotropic pole shoe elements. In particular, these two additional pole shoe elements can be arranged such that they exhibit a lower magnetic resistance in the second direction than in the first direction. In this way, effective conduction of the magnetic flux in the second direction through the actuator element can be ensured by means of the two additional pole shoe elements in the second operating state, while in the first operating state, magnetic flux through the two additional pole shoe elements in the first direction is reduced or prevented, bypassing the actuator element.

[0027] In alternative embodiments, the two additional pole shoe elements are not provided as magnetically anisotropic pole shoe elements. This may be particularly appropriate if, due to the design of the actuator arrangement, a magnetic flux through the two additional pole shoe elements in the first direction, bypassing the actuator element, is not expected in the first operating state, or not to an extent that significantly reduces the efficiency of the actuator arrangement.

[0028] In the various embodiments, each or all of the magnetically anisotropic pole shoe elements can be assigned a wedge-shaped flux guide element, with the above statements regarding the flux guide element applying accordingly.

[0029] The actuator element can be designed as a rod-shaped actuator element which has a greater extent along a longitudinal direction (running in the second direction) than in a transverse direction (running in the first direction). In particular, a rod-shaped actuator element can have an aspect ratio between its extent along the longitudinal direction and its extent along the transverse direction greater than or equal to 3:1.In particular, in connection with a rod-shaped actuator element with a longitudinal direction along the second direction, an arrangement with two pole shoe elements can be provided, which are arranged along the first direction on opposite sides of the actuator element and are each configured to guide the first magnetic flux in the first direction through the actuator element, wherein the two pole shoe elements are provided as magnetically anisotropic pole shoe elements and are arranged such that they have a lower magnetic resistance in the first direction than in the second direction.In this way, the two pole shoe elements ensure effective transverse conduction of the magnetic flux through the rod-shaped actuator element in the first operating state, while in the second operating state, the longitudinal magnetic flux through the two pole shoe elements is reduced or prevented, bypassing the actuator element. This can be particularly advantageous if, due to the smaller cross-section and length of the actuator element in the longitudinal direction, there is a tendency for the magnetic flux in the second operating state to flow significantly through the two pole shoe elements in the second direction, thus reducing the magnetic flux in the second direction within the actuator element.In this case, the loss of magnetic flux effective in the actuator element is reduced by means of the pole shoe elements with increased magnetic resistance in the second direction (longitudinal direction of the actuator element). While in some embodiments two additional pole shoe elements may be provided as magnetically anisotropic pole shoe elements as described above, in alternative embodiments this can be omitted in the case of a large aspect ratio between the longitudinal and transverse directions of the actuator element, particularly if it is not expected that the magnetic flux in the first operating state will flow to a significant extent via the two additional pole shoe elements in the first direction and thus reduce the magnetic flux in the first direction in the actuator element.

[0030] In general, any suitable cross-section can be provided for a rod-shaped actuator element. For example, a rod-shaped actuator element according to the disclosure can have a rectangular, for example square, cross-section, a round, for example circular or oval, cross-section, or a polygonal, for example triangular, hexagonal or trapezoidal, cross-section.

[0031] In alternative configurations, the actuator element can be formed with a shape other than a rod. For example, the actuator element can be a cube-shaped actuator element.

[0032] In other alternative configurations, the actuator element can be provided with any shape suitable for a given application. For example, an actuator element can be formed as any polyhedron or with a curved shape.

[0033] According to one embodiment, the first and second flux-generating devices are each formed with a flux-generating element that generates intersecting magnetic fields inclined to the first and second directions. In this case, a superposition of the magnetic fields generated by the first and second flux-generating devices results in the first magnetic flux in the first direction in the first operating state and in the second magnetic flux in the second direction in the second operating state.In particular, it may be provided that the first or the second flux-generating device is formed with a coil as a flux-generating element and that the first and the second operating state differ in the current direction of this coil, whereby the direction of the generated magnetic field is reversed and the superposition of the magnetic fields running obliquely to the first and the second direction results in the first and second magnetic flux according to the first and second operating state, respectively.

[0034] The first flow generation device and the second flow generation device can each have at least two flow generation elements. In particular, it can be provided that the flow generation elements are arranged in a rectangular, especially square, arrangement such that the flow generation elements of the first flow generation device are diagonally opposite each other in the rectangular (square) arrangement, and the flow generation elements of the second flow generation device are diagonally opposite each other in the rectangular (square) arrangement.

[0035] The actuator element can be arranged centrally with respect to the arrangement of the two flux-generating elements of the first flux-generating device and the two flux-generating elements of the second flux-generating device. Alternatively, the actuator element can be arranged eccentrically with respect to the arrangement of the flux-generating elements in at least one spatial direction. In this case, the magnetic flux generated by the flux-generating elements can be guided to and through the actuator element by means of the pole shoe element and / or by means of one or more further pole shoe elements, according to the first or second operating state, respectively. In a preferred embodiment, the actuator element can be arranged offset from a plane spanned by the flux-generating elements arranged in a rectangular (in particular, square) configuration. Such an arrangement allows for a particularly space-saving actuator arrangement.

[0036] The first and second flux-generating devices can each be formed with at least two coils as flux-generating elements. The at least two coils of the first flux-generating device can be connected in series, and the at least two coils of the second flux-generating device can also be connected in series. In such an embodiment, switching between the first and second operating states can be achieved by means of the control device by reversing the current direction of the coils of the first flux-generating device while the current direction of the coils of the second flux-generating device remains unchanged, or vice versa. In this case, the magnetic flux generated by the flux-generating elements can be controlled by means of the pole shoe element and / or by means of one or more further pole shoe elements according to the first or second operating state.The second operating state is guided to and through the actuator element, whereby the direction of current application in the operating states leads to a different superposition of the fields generated by the coils and thus to a magnetic flux in the first direction through the actuator element or to a magnetic flux in the second direction through the actuator element. This can be provided in particular for an embodiment in which the flux-generating elements are arranged in a rectangular (square) arrangement such that the flux-generating elements of the first flux-generating device are diagonally opposite each other in the rectangular arrangement and the flux-generating elements of the second flux-generating device are diagonally opposite each other in the rectangular arrangement.

[0037] The first flux-generating device can be formed with at least two coils as flux-generating elements, while the second flux-generating device is formed with at least two permanent magnets as flux-generating elements. In such an embodiment, it is particularly provided that the second flux-generating device provides a magnetic flux with a constant orientation by means of the at least two permanent magnets, and switching between the first and second operating states can be effected by reversing the current direction of the coils of the first flux-generating device by means of the control device. In this case, the magnetic flux generated by the flux-generating elements can be controlled by means of the pole shoe element and / or by means of one or more further pole shoe elements according to the first or second operating state.The second operating state is guided to and through the actuator element, wherein the direction of current flow to the coils of the first flux-generating device in the operating states leads to a different superposition of the fields generated by the coils and thus to a magnetic flux in the first direction through the actuator element or to a magnetic flux in the second direction through the actuator element. This can be provided in particular for an embodiment in which the flux-generating elements are arranged in a rectangular (especially square) arrangement such that the flux-generating elements of the first flux-generating device are diagonally opposite each other in the rectangular arrangement and the flux-generating elements of the second flux-generating device are diagonally opposite each other in the rectangular arrangement.

[0038] In an alternative embodiment, the first flux-generating device and the second flux-generating device can each have a flux-generating element formed by a coil, wherein the first flux-generating device is configured to generate the first magnetic flux and the second flux-generating device is configured to generate the second magnetic flux. Thus, independent coils can be provided, with the magnetic flux generated by one of the flux-generating devices directly serving to establish the first or second operating state, respectively.In this case, it can be provided, in particular, that the control device activates the first flux-generating device and deactivates the second flux-generating device to set the first operating state, and deactivates the first flux-generating device and activates the second flux-generating device to set the second operating state, or vice versa. In such an embodiment, the setting of the first and second operating states can, in particular, be carried out without being based on a superposition of the magnetic fluxes generated by the first and second flux-generating devices.

[0039] In a further alternative embodiment, the first flux-generating device can be formed with a coil as the flux-generating element, while the second flux-generating device is formed with a permanent magnet as the flux-generating element, wherein the first flux-generating device is configured to generate the first magnetic flux and the second flux-generating device is configured to generate the second magnetic flux. In such an embodiment, the actuator arrangement, in its rest state (i.e., without current being supplied to the coil of the first flux-generating device), assumes the second operating state through the action of the permanent magnet of the second flux-generating device.To generate the first operating state, the coil of the first flux-generating device is energized, the magnetic flux generated by the coil being so large that it superimposes itself in the actuator element on the flux generated by the permanent magnet of the second flux-generating device, resulting in the first magnetic flux being established in the actuator element. It is understood that, even mathematically, such a superposition cannot achieve a rotation of exactly 90 degrees of the resulting magnetic flux in the actuator element. Therefore, as disclosed, a first magnetic flux passing through the actuator element in the first direction and a second magnetic flux passing through the actuator element in the second direction are to be understood as fluxes whose direction is sufficiently close to the first and second directions, respectively, to establish the first and second directions.The second length is achieved through the area of ​​the actuator element. Thus, a preload of the actuator arrangement towards the second operating state is achieved.

[0040] Alternatively, the second flux-generating device can be formed with a coil as the flux-generating element, while the first flux-generating device is formed with a permanent magnet as the flux-generating element, wherein the first flux-generating device is configured to generate the first magnetic flux and the second flux-generating device is configured to generate the second magnetic flux. The preceding descriptions of a first flux-generating device formed with a coil and a second flux-generating device formed with a permanent magnet apply here, with the corresponding adjustments, so that a bias of the actuator arrangement towards the first operating state is achieved.

[0041] A biasing device may be provided for the first or second flux-generating device, configured to provide a magnetic bias corresponding to the operation of the first or second flux-generating device, respectively, when the first and second flux-generating devices are not in operation. In this case, the biasing device is provided in addition to the flux-generating devices. For example, the biasing device may be formed with one or more permanent magnets arranged in a magnetic circuit of the actuator assembly such that they provide a magnetic flux corresponding to the operation of the first or second flux-generating device, respectively.

[0042] The direction of the magnetic bias provided by the biasing device can be adjusted by means of the first flux-generating device and / or the second flux-generating device. For example, the biasing device can be formed with one or more elements made of a magnetically semi-hard material, arranged in a magnetic circuit of the actuator assembly such that, when the actuator assembly is operating in the first or second operating state, they assume a magnetization corresponding to the respective operating state and maintain that operating state when the first and second flux-generating devices are not in operation.If the actuator arrangement is subsequently controlled according to the other operating state, the elements made of the magnetically semi-hard material are reversed so that they maintain the other operating state when the first flux-generating device and the second flux-generating device are not in operation.

[0043] In embodiments with a preload device, it may be provided that the preload is overcome by means of the flux-generating device to which the preload device is assigned, by means of the flux-generating device to which the preload device is not assigned, or by means of both flux-generating devices, in order to achieve an operating state that does not correspond to the preload achieved by means of the preload device. For example, the preload device of a coil may be assigned to the relevant flux-generating device and provide a magnetic flux corresponding to operation of the coil with a specific current direction. In this case, operation of the relevant coil with the opposite current direction may be provided to overcome the preload and achieve a desired operating state of the actuator arrangement.

[0044] A further pre-tensioning device may be provided, in which case the pre-tensioning device is assigned to the first flux-generating device and the further pre-tensioning device is assigned to the second flux-generating device. The provisions described above in connection with the pre-tensioning device may apply accordingly to the further pre-tensioning device.Particularly in embodiments in which the first operating state and the second operating state are achieved by superimposing the magnetic fluxes generated by the first flux-generating device and the second flux-generating device, a preload towards the first or the second operating state can then be provided by means of the preloading device and the further preloading device, whereby the other operating state in question is then set by controlling the first and / or the second flux-generating device by overcoming the magnetic preload.

[0045] Analogous to embodiments with a pre-tensioning device and a further pre-tensioning device, a pre-tensioning device associated with the first or the second flux-generating device can be provided, wherein the other flux-generating device in question itself provides a pre-tension, for example, by being formed with one or more permanent magnets. In this case, the embodiments described above with reference to the pre-tensioning device and the further pre-tensioning device can be provided accordingly.

[0046] In general, the actuator arrangement can be designed so that the magnetic flux generated by the flux-generating elements is guided to and through the actuator element by means of the pole shoe element and / or by means of one or more additional pole shoe elements, according to the first or second operating state. The shape and other configuration of the additional pole shoe elements can be adapted to the design of the actuator arrangement, for example, to the number, type, and arrangement of flux-generating elements. In particular, one or all of the additional pole shoe elements can be provided as magnetically anisotropic pole shoe elements, as previously explained by way of example for various embodiments. The pole shoe element and the additional pole shoe elements then form one or more magnetic circuits, each encompassing the actuator element, in order to provide the desired magnetic flux in the actuator element.

[0047] In various embodiments, the actuator arrangement can additionally be configured for a third operating state in which the actuator element is penetrated by a third magnetic flux in a third direction, perpendicular to both the first and second directions. For example, the actuator arrangement can include a third flux-generating device configured to generate the third magnetic flux, or the third magnetic flux can be generated by superimposing the magnetic flux generated by the third flux-generating device with the magnetic flux generated by the first flux-generating device and / or with the magnetic flux generated by the second flux-generating device. The third flux-generating device can incorporate the same configurations as described above in connection with the first and / or second flux-generating devices.Alternatively, the actuator arrangement can be configured without a third flux generation device, in which case the third magnetic flux can be generated by a targeted superposition of the magnetic flux generated by the first flux generation device and the magnetic flux generated by the second flux generation device, in addition to the first and second magnetic fluxes. In connection with the third operating state, a corresponding arrangement with the pole shoe element and, if necessary, further pole shoe elements can be provided, which allows the provision of the third operating state, whereby the above statements regarding the design of magnetic circuits in connection with two operating states can apply accordingly.

[0048] Particularly in connection with a third operating state, but also in other embodiments, the magnetically anisotropic pole shoe element and optionally further anisotropic pole shoe elements can exhibit a lower magnetic resistance in one direction than in two directions perpendicular to that one direction and to each other. For example, the magnetically anisotropic pole shoe element and optionally further anisotropic pole shoe elements can be formed as an arrangement of rod-shaped elements with low magnetic resistance, which are arranged in a matrix-like configuration and separated by a material with high magnetic resistance, in particular a non-magnetic material, such as epoxy resin or air.

[0049] An actuator, particularly a linear actuator, can be provided with the actuator assembly. The actuator assembly can be used, in particular, in applications where linear motion is required and where (passive) holding forces are desired in one or more positions. For example, an actuator comprising the actuator assembly can be used to actuate a valve, a gripper (e.g., on a robot arm), a locking device, and / or in pick-and-place applications.

[0050] The configurations described above in connection with the actuator arrangement can be provided for the procedure for operating an actuator arrangement.

[0051] In the operation of an actuator arrangement according to the disclosure, it may be provided that the first flux-generating device and / or the second flux-generating device, or one or more of flux-generating elements of the first and / or the second flux-generating device, are controlled in such a way that the flux density passing through the actuator element changes in the first operating state and / or in the second operating state and / or that one or more further operating states are established in which the actuator element is passed through by a further magnetic flux that runs in a direction arranged at an angle to the first direction and the second direction.For example, flux-generating elements of the first and / or the second flux-generating device can be controlled in such a way that a magnetic flux generated by them changes, for example by varying the current with which a flux-generating element formed as a coil is energized. Alternatively or additionally, it can be provided that the first and the second flux-generating device are operated simultaneously, such that the magnetic fluxes superimpose in such a way that a magnetic flux passes through the actuator element in a direction arranged at an angle to the first and second directions.In this way, a superposition can be achieved by coordinated changes to the magnetic fluxes generated by the first and second flux-generating devices such that the direction of a magnetic flux passing through the actuator element rotates, in particular continuously or quasi-continuously from the first to the second direction or vice versa. Description of exemplary implementations

[0052] Further examples of implementation are explained in more detail below with reference to figures in a drawing. These show: Fig. 1 a schematic representation of an actuator element comprising a magnetic shape memory alloy in two operating states; Fig. 2a a schematic representation of a known actuator arrangement in a first operating state; Fig. 2b a schematic representation of the known actuator arrangement in a second operating state; Fig. 3 a magnetic equivalent circuit of an actuator arrangement; Fig. 4a a schematic representation of an actuator arrangement in a first operating state; Fig. 4b a schematic representation of the actuator arrangement in a second operating state; Fig. 5 a schematic representation of another actuator arrangement; Fig. 6 a comparative representation of magnetic fluxes in actuator arrangements; Fig. 7 a schematic representation of an alternative actuator arrangement; Fig. 8 schematic representations of operating states of an actuator arrangement with a permanent magnet flux generation device; Fig.Fig. 9 Schematic representations of operating states of an actuator arrangement with a preload device; Fig. 10 Schematic representations of operating states of another actuator arrangement with a preload device; Fig. 11 Schematic representations of operating states of an actuator arrangement with an adjustable preload device; Fig. 12 Schematic representations of alternative designs for actuator arrangements; Fig. 13 Schematic representations of further alternative designs for actuator arrangements; Fig. 14 A schematic representation of an additional design of an actuator arrangement; Fig. 15a A schematic representation of an actuator arrangement with independent coil sets; Fig. 15b A schematic representation of another actuator arrangement with independent coil sets; Fig. 16 Schematic representations of various configurations of coil sets for an actuator arrangement; Fig.Fig. 17 shows a schematic representation of a pole shoe element formed with a laminate; and Fig. 18 shows a schematic representation of another pole shoe element formed with a laminate.

[0053] The Fig. 1 Figure 1 shows an actuator element 1 made of a magnetic shape memory alloy (MSMA). The actuator element 1 is provided as a rod-shaped actuator element and elongates along its longitudinal direction 2 when it is penetrated by a (sufficiently large) first magnetic flux 3 that runs transversely to the longitudinal direction 2 (elongation).

[0054] If the actuator element 1 is penetrated by a second magnetic flux 4 (of sufficient magnitude) along the longitudinal direction 2, it shortens in the longitudinal direction 2 (contraction). This change in shape is caused by an alignment of magnetic unit cells within the shape memory alloy along the magnetic field penetrating the actuator element 1. In general, a sufficiently large magnetic field in an MSMA element causes a contraction (tension) in the field direction and, correspondingly, an elongation (compression) perpendicular to it, whereby both forces can be utilized. Without a magnetic field penetrating the actuator element 1, the actuator element 1 retains its shape, although mechanical deformation of the actuator element is possible if an external force, overcoming the so-called twin stress, acts on the actuator element 1 and thus changes the alignment of the magnetic unit cells through mechanical action.

[0055] The Fig. 2aFigure 1 shows an actuator arrangement with an MSMA actuator element 1, as known from document US 10,581,345 B2. The actuator arrangement comprises a first flux-generating device 5 and a second flux-generating device 6. The first flux-generating device 5 is formed with two coils 7a, 7b, and the second flux-generating device 6 is formed with two coils 8a, 8b. The coils 7a, 7b, 8a, 8b are arranged in a rectangular, specifically square, configuration, with the coils 7a, 7b of the first flux-generating device 5 and the coils 8a, 8b of the second flux-generating device 6 diagonally opposite each other, as shown in the Fig. 2a It is evident that the coils 7a, 7b of the first flux-generating device 5 are connected in series and the coils 8a, 8b of the second flux-generating device 6 are connected in series.

[0056] In the Fig. 2aFigure 1 shows a first operating state of the actuator arrangement in which the actuator element 1 is penetrated by a first magnetic flux 3. Fig. 2b Figure 1 shows a second operating state in which the actuator element 1 is permeated by a second magnetic flux 4. The magnetic fluxes are illustrated by arrows. The operating states are achieved by energizing the flux-generating devices 5 and 6, whereby a yoke arrangement 9 made of soft iron guides the magnetic flux to the actuator element 1. To establish the first operating state, the flux-generating devices 5 and 6 are energized as indicated by the current direction symbols in the figure. Fig. 2a illustrated. This results in the following for the representation of the Fig. 2a Horizontally adjacent coils 7a, 8a / 7b, 8b generate an opposite direction of magnetic flux, such that the magnetic flux across the center of the yoke arrangement 9 is in accordance with the Fig. 2avertical direction and thus corresponding to the first magnetic flux through the actuator element 1. For a change to the second operating state, the current direction of the first flux-generating device 5 is reversed, while the current direction of the second flux-generating device 6 remains unchanged. Thus, for the representation of the Fig. 2b Horizontally adjacent coils 7a, 8a / 7b, 8b have the same direction of generated magnetic flux, such that the magnetic flux passes over the center of the yoke arrangement 9 in accordance with the Fig. 2b horizontal direction and thus corresponding to the second magnetic flux 4 through the actuator element 1.

[0057] In the depictions of the Figures 2a and 2bThe strength of the magnetic flux is illustrated by the thickness of the arrows. This shows that in the second operating state, a significant portion of the magnetic flux bypasses the actuator assembly 1 and travels horizontally through the yoke assembly 9. This results in a high effective loss of magnetic flux available for deformation of the actuator element 1, so that the efficiency of the actuator assembly is low with respect to the second operating state.

[0058] The Fig. 3 Figure 1 shows a magnetic equivalent circuit diagram of the inner region of an actuator arrangement. The magnetic flux in the actuator element 1 is essentially determined by the ratios of the magnetic resistances of the surrounding sections 9a, 9b, 9c, 9d of the yoke arrangement 9, the actuator element 1, and the intervening air gaps 10.

[0059] The Figures 4a and 4bshow an actuator arrangement as revealed, in which, unlike the one in the Figures 2a and 2b The arrangement shown includes a magnetically anisotropic pole shoe element 11. Here, the Fig. 4a analogous to the Fig. 2a the initial operating state and the Fig. 4b shows analogous to the Fig. 2b the second operating state of the actuator arrangement. The pole shoe element 11 is magnetically anisotropic in that it is magnetically anisotropic along the first direction (in the representation of the Figures 4a and 4b vertically) exhibits a significantly lower magnetic resistance than along the second direction (in the representation of the Figures 4a and 4bhorizontal). This ensures that in the first operating state, the first magnetic flux is effectively guided through the actuator element 1. In the second operating state, the high magnetic resistance of the pole shoe element 11 along the second direction reduces the portion of the magnetic flux passing through the pole shoe element 11, thereby increasing the portion of the flux passing through the actuator element 1 in the second direction, thus improving the efficiency of the actuator arrangement in the second operating state. To enhance this effect, a second pole shoe element 12 is arranged opposite the first pole shoe element. The second pole shoe element 12 is also a magnetically anisotropic pole shoe element, which exhibits a significantly lower magnetic resistance along the first direction than along the second direction.

[0060] In the Fig. 4bA further development is shown with dashed lines, in which additional magnetically anisotropic pole shoe elements 13, 14 are provided. These elements exhibit a significantly higher magnetic resistance along the first direction than along the second direction, thus effectively guiding the second magnetic flux through the actuator element 1 in the second operating state. Conversely, in the first operating state, the high magnetic resistance of the pole shoe elements 13, 14 along the first direction reduces the portion of the magnetic flux passing through the pole shoe elements 13, 14. The yoke arrangement can include further pole shoe elements (not shown) for guiding the magnetic flux. These pole shoe elements can be either magnetically anisotropic or magnetically isotropic. One or both of these additional magnetically anisotropic pole shoe elements 13, 14 can also be provided accordingly in the embodiments described below.

[0061] The actuator arrangement includes a control device 15 with which the current supply to the flux-generating devices 5, 6 is controlled to set the first and second operating states.

[0062] The Fig. 5 shows another actuator arrangement. Compared to the schematic representation of the Figures 4a and 4b is in the Fig. 5A flux guide element 16 according to the invention is recognizable, which in the illustrated embodiment is made of soft iron. The flux guide element 16 is formed with a wedge geometry facing the pole shoe element 11, such that the flux guide element 16 contacts the pole shoe element in a central region located along the second direction, and an air gap is formed that increases along the second direction towards the edges of the flux guide element 16. The magnetic resistance of the arrangement consisting of the pole shoe element 11 and the flux guide element 16 is increased in the edge regions due to the air gap. This further reduces the magnetic flux passing through the pole shoe element past the actuator element 1 in the second operating state. Another flux guide element 17 with a wedge geometry is associated with the pole shoe element 12 in an analogous arrangement.

[0063] In the actuator arrangement according to the Fig. 5The axes of coils 7a, 7b, 8a, 8b lie in a plane. The actuator element 1 is offset from this plane and thus eccentric with respect to coils 7a, 7b, 8a, 8b, but projected onto the plane, it is centered on coils 7a, 7b, 8a, 8b. This results in a particularly compact design in the illustrated arrangement. In alternative embodiments, the actuator element can also lie within the plane or, in addition to being offset from the plane, can also be offset from the plane relative to coils 7a, 7b, 8a, 8b when projected onto the plane.

[0064] The Fig. 6 This illustrates the efficiency increase achieved through the use of magnetically anisotropic pole shoe elements. The left side of the diagram shows... Fig. 6The areas below a symmetry axis in the second operating state are shown superimposed for different embodiments of the central region of an actuator arrangement. Below, for comparison purposes, is an arrangement without a magnetically anisotropic pole shoe element 11. The arrangement shown in the middle is formed with a magnetically anisotropic pole shoe element 11. The arrangement shown above has a wedge-shaped flux guide element 16 in addition to a magnetically anisotropic pole shoe element 11. The magnetic flux is represented by arrows, with a thicker arrow symbolizing a higher flux density. As the Fig. 6As can be seen, in an arrangement without a magnetically anisotropic pole shoe element 11, the magnetic flux can thus bypass the actuator element 1 unhindered via the magnetically isotropic pole shoe element, thereby reducing the effective magnetic flux in the actuator element 1 and resulting in low efficiency of the actuator arrangement in the second operating state. In the actuator arrangement shown in the center, with a magnetically anisotropic pole shoe element 11, a magnetic flux in the second direction is impeded by the pole shoe element, thereby increasing the flux density in the actuator element 1 and improving efficiency. In the actuator arrangement shown above, the air gaps between the pole shoe element 11 and the flux guide element 16, achieved through the wedge geometry, additionally impede a flux in the second direction through the flux guide element 16, further increasing efficiency in the illustrated embodiment.

[0065] This effect is in the Fig. 6 This is illustrated again using several graphs. Here, the graphs show the course of the magnetic flux density (ordinate) in actuator element 1 along the course of actuator element 1 in the second direction (abscissa). It can be seen that for the in the Fig. 6 The actuator arrangement shown in the lower left, according to the dotted graph, achieves only a low magnetic flux density in actuator element 1. In contrast, for the one shown in the Fig. 6The actuator arrangement shown in the center left, with a magnetically anisotropic pole shoe element 11, increases the magnetic flux density (dashed graph). The graph shown with a solid line shows that, in contrast, the use of a flux guide element 16 with wedge geometry in the actuator arrangement shown in the upper left results in a further increase in the magnetic flux density in the actuator element 1, which is also significantly more homogeneous.

[0066] The Fig. 7 This shows an alternative design of an actuator arrangement. Compared to the actuator arrangement of the Fig. 5 indicates in the actuator arrangement of the Fig. 7 The first flux-generating device 5 comprises four coils 7a, 7b, 7c, 7d and the second flux-generating device 6 comprises four coils 8a, 8b, 8c, 8d. Each of the coils 7a, 7b, 8a, 8b is part of the actuator arrangement of the Fig. 5The coils are doubled. This allows for an even higher field strength. In further developments, this concept can be extended to any multiple of two coils.

[0067] The Fig. 8 shows an actuator arrangement in which, compared to the actuator arrangement of the Figures 4a and 4b The second flux-generating device 6 is formed with two permanent magnets 18a, 18b instead of coils. This results in the same permanent state as when the coils 8a, 8b of the second flux-generating device 6 of the actuator arrangement are energized. Figures 4a and 4b If the coils 7a, 7b of the first flux-generating device 5 are not energized, the following results in the Fig. 8The state shown on the left does not produce any movement, in which no magnetic flux corresponding to the first or second operating state is established in the actuator element 1. When the coils 7a, 7b of the first flux-generating device 5 are energized, the first operating state is then established according to the direction of the current ( Fig. 8 middle) or the second operating state ( Fig. 8 (right). In this way, a particularly energy-efficient actuator arrangement with fewer coils can be provided.

[0068] During the Fig. 9 The actuator arrangement shown is, in comparison to the actuator arrangement of the Fig. 8A biasing device 19 associated with the first flux-generating device 5 is provided, which is formed with two permanent magnets 20a, 20b arranged inside the respective coils 7a, 7b of the first flux-generating device 5. The magnetic flux generated by the permanent magnets 20a, 20b of the biasing device 19 creates a state corresponding to the current applied to the first flux-generating device 5 without energization. By energizing the coils 7a, 7b of the first flux-generating device 5, this state can be amplified by applying a stronger current, depending on the direction of current application. Fig. 9 right) or compensate ( Fig. 9(in the middle), so that a different operating state is achieved compared to the operating state generated by the biasing device 19. Inside the coils 7a, 7b, a soft magnetic core arranged in series with an air gap is arranged parallel to the permanent magnets 20a, 20b. In the event of compensation of the magnetic bias, the magnetic flux generated by the permanent magnets 20a, 20b is short-circuited via the respective core and air gap. In the case of short (narrow) permanent magnets 20a, 20b in the axial direction of the coils 7a, 7b, a short circuit can also be possible exclusively via an air gap arranged parallel to the respective permanent magnet 20a, 20b.

[0069] In the execution of the Fig. 9 The actuator arrangement is pre-tensioned to the second operating state by means of the pre-tensioning device 19. In contrast, the Fig. 10An embodiment in which the actuator arrangement is biased towards the first operating state by means of the biasing device 19. This is achieved by orienting the magnetization direction of the permanent magnets 20a, 20b relative to the actuator device. Fig. 9 The opposite is true.

[0070] In the actuator arrangement of the Fig. 11 The preloading device 19 is formed with two preloading elements 21a, 21b made of magnetically semi-hard material. Magnetically semi-hard materials combine properties of soft iron and permanent magnets, since, like the latter, they have a high remanent flux density without an excitation field, but unlike permanent magnets, they can be remagnetized even at a low coercive field strength. This allows them to be aligned by a brief current and then maintain the flux without current. Thus, the actuator arrangement of the Fig. 11that the operating state established by energizing the coils 7a, 7b of the first flux-generating device 5 is maintained even after the energization is discontinued, since the magnetically semi-hard material of the preload elements 21a, 21b has been remagnetized. Thus, in the Fig. 11 The upper left shows a current supply for setting the second operating state, which then, after the current supply ends, is shown in the illustration. Fig. 11 The top right position is retained. Accordingly, it shows Fig. 11 The lower left is a current setting for establishing the initial operating state. This state is then set according to the diagram after the current is switched off. Fig. 11 Keep bottom right corner.

[0071] The Figure 12 , 13 and 14Alternative designs for actuator arrangements are shown. The underlying concept in each case is symmetrical. Therefore, swapping the stationary (without changing the current or magnetic field direction between operating states) and controlled coil pairs does not alter the behavior for any of the variants and is thus always implied. Without limiting generality, several further configuration options with the known position of the static branch, as explained above, are presented here. These are alternative embodiments of the three actuator arrangements of the Figures 8 , 9 and 10 The static pair of permanent magnets 18a, 18b without a coil can in all cases also be supplemented by additional coils 8a, 8b, which can be operated in amplification or compensation mode (see explanations above). This results in the following: Fig. 12The actuator arrangements shown with additional control combinations, wherein the arrangement is in Fig. 12 On the left, a further development of the arrangement Fig. 8 is the arrangement in Fig. 12 in the middle a further development of the arrangement Fig. 9 is and the arrangement in Fig. 12 On the right, a further development of the arrangement Fig. 10 is.

[0072] The static pair of permanent magnets 18a, 18b of the actuator arrangement of the Fig. 11 can also be replaced by coils 8a, 8b, as in the Fig. 13 Shown above. Fig. 13 The figure below shows a further development of the actuator arrangement based on this, in which the respective core of the coils 8a, 8b is formed with magnetically semi-hard biasing elements 21c, 21d.

[0073] The Fig. 14Figure 1 shows an exemplary actuator arrangement with an asymmetry within the second flux generation device 6, which in this embodiment is formed with a coil 8a and a permanent magnet 18b.

[0074] The in the Figures 8 to 14 The concepts presented can be derived accordingly from the representation of the Figures 4a and 4b transferred to different coil arrangements, for example to arrangements with an off-center actuator element (see Fig. 5 ), arrangements with more than two flow-generating elements per flow-generating device (see Fig. 7 ) or arrangements with independent coil sets, as explained below.

[0075] In the Figures 15a and 15bActuator arrangements are shown in which the flux-generating devices 5, 6 form independent coil sets, i.e., the first flux-generating device 5 generates the first magnetic flux 3, and the second flux-generating device 6 independently generates the second magnetic flux 4. The first and second flux-generating devices 5, 6 are thus activated independently of each other, and a superposition of the generated magnetic fields is not intended, although it remains possible. In the actuator arrangements of the Figures 15a and 15b The first flux-generating device 5 is formed with a coil 7a and the second flux-generating device 6 is formed with a coil 8a. Comparing the in the Figures 15a and 15b The arrangements shown indicate the actuator arrangement of the Fig. 15a a more compact design, while the actuator arrangement of the Fig. 15bThis allows easier access to the MSMA actuator element 1, which can, for example, simplify maintenance. The basic topology is identical for both actuator arrangements shown. The exact positioning of coils 7a, 8a on the respective core is shown only as an example and can be varied or even divided as desired. By adding a third, independent set of coils, the actuator arrangement can be extended to allow for a third flux direction in the actuator element, corresponding to a third operating state, as described above.

[0076] Furthermore, for actuator arrangements with flux-generating devices 5, 6 formed as independent coil sets, the use of permanent magnets or semi-hard materials to increase efficiency is also possible, whereby the preceding explanations apply accordingly. Since the concept of the in the Figures 15a and 15bIn the actuator arrangements shown, where coil 7a serves exclusively for elongation and coil 8a exclusively for contraction of the actuator element 1, the respective current direction and thus field direction is irrelevant. Only the magnitude is relevant for the desired functionality. Each of the two cored coils 7a, 8a can be supplemented by a permanent magnet 20a, as shown in the Fig. 16 The second illustration from the left shows an example of a coil 7a (with parallel air gap and core) (far left in the Fig. 16 (For comparison, a coil 7a without modification). The permanent magnet 20a allows a bias to be applied in favor of the corresponding movement (contraction or elongation). A rotation of the magnet 20a by 180° leads to the same result. If both directions are biased, a balanced state without movement results again. The complete replacement of a coil 7a, 8a (in the Fig. 16The second illustration from the right, coil 8a), shows an example of this. The addition of a permanent magnet 18a is also conceivable. To compensate for this effect, a very high excitation of the other coil is required. Furthermore, each of the coils 7a, 8a can be supplemented by an element 21a made of a semi-hard alloy, which can be activated or compensated for by the coils. This is shown for coil 7a as an example in the Fig. 16 Shown on the far right. Thus, for each of the coils 7a, 8a, there are four possible modifications, which can be combined as desired according to the specific requirements of a given application.

[0077] The Fig. 17Figure 1 shows a pole shoe element 11 formed with a laminate 22. The laminate 22 consists of an arrangement of several layers in which first layers 23 made of a first magnetic material, for example soft iron, and second layers 24 made of a non-magnetic material, for example epoxy resin, are alternately bonded together. To couple a magnetic flux into the pole shoe element 11, it has a coupling element 25 made of a magnetic material, for example the first material.

[0078] The Fig. 18 shows an alternative embodiment of a pole shoe element 11 formed with a laminate 22. In the embodiment of the Fig. 18The second layers 24 are formed with air, filling the gaps between the first layers 23. In this case, the first layers are formed integrally with the coupling element 25. Alternatively, the second layers 24 can be formed with another gas, a gas mixture, or a liquid, forming non-magnetic second layers 24 between the first layers 23.

[0079] When a pole shoe element 11, 12, 13, 14, provided as a laminate 22, is combined with a flux guide element 16, 17 formed with a wedge shape, the weighting of the field along or across the actuator element 1 can be adjusted according to the geometry and desired behavior by dimensioning the wedge geometry and the anisotropic laminate. This applies to both the active case (coil as flux-generating element) and the passive case (permanent magnet as flux-generating element) as explained above. Furthermore, the passive case can be adjusted separately by selecting the magnetic bias. This allows the weighting in the active and passive cases to be adjusted independently to a certain extent. For example, a passive bias in the first direction can be combined with a pole shoe element that favors the second direction.In this way, it can be made easier in compensation mode to actively set the second operating state while a bias to the first operating state is provided.

[0080] The features disclosed in the foregoing description, the claims and the drawing can be important for the realization of the various embodiments, both individually and in any combination.

Claims

1. Actuator assembly, comprising - an actuator element (1), wherein the actuator element (1) comprises a magnetic shape memory alloy, and wherein a region of the actuator element (1) - has a first length in a first direction, if the region is penetrated by a magnetic field in the first direction, and - has a second length in the first direction, different from the first length, if the region is penetrated by a magnetic field in a second direction that is perpendicular to the first direction; - a first flux generating device (5) for generating a magnetic flux; - a second flux generating device (6) for generating a magnetic flux; - a control device (15) configured to control the first flux generating device (5) and / or the second flux generating device (6) according to a first operating state and a second operating state, such that - in the first operating state, the actuator element (1) is penetrated by a first magnetic flux in the first direction, and - in the second operating state, the actuator element (1) is penetrated by a second magnetic flux in the second direction; and - a pole shoe element (11, 12, 13, 14) which is configured to guide the first magnetic flux in the first direction through the actuator element (1) or is configured to guide the second magnetic flux in the second direction through the actuator element (1), characterized in that the pole shoe element (11, 12, 13, 14) is provided as a magnetically anisotropic pole shoe element and by a flux guiding element (16, 17) assigned to the pole shoe element (11, 12, 13, 14), which is formed with a wedge shape and is arranged such that a magnetic resistance of the arrangement of pole shoe element (11, 12, 13, 14) and assigned flux guiding element (16, 17) in the direction of lower magnetic resistance of the pole shoe element (11, 12, 13, 14) is higher in edge regions of the arrangement of pole shoe element (11, 12, 13, 14) and assigned flux guiding element (16, 17) opposite along the direction of higher magnetic resistance of the pole shoe element (11, 12, 13, 14) than in a central region of the arrangement of pole shoe element (11, 12, 13, 14) and assigned flux guiding element (16, 17).

2. Actuator assembly according to claim 1, wherein - the pole shoe element (11, 12, 13, 14) is formed with a laminate (22); - the laminate (22) consists of an arrangement of a plurality of layers; - the plurality of layers comprises first layers (23) of a first material and second layers (24) of a second material; and - in the arrangement of a plurality of layers, first layers (23) and second layers (24) are alternately arranged one above the other, wherein the first material has a first relative permeability, and the second material has a second relative permeability which is different from the first relative permeability.

3. Actuator assembly according to claim 1 or 2, wherein the pole shoe element (11, 12, 13, 14) is formed with a magnetically anisotropic material.

4. Actuator assembly according to at least one of the preceding claims with two pole shoe elements (11, 12) which are arranged along the first direction on opposite sides of the actuator element (1) and are each configured to guide the first magnetic flux in the first direction through the actuator element (1), wherein the two pole shoe elements (11, 12) are provided as magnetically anisotropic pole shoe elements.

5. Actuator assembly according to claim 4 with two further pole shoe elements (13, 14) which are arranged along the second direction on opposite sides of the actuator element (1) and are each configured to guide the second magnetic flux in the second direction through the actuator element (1).

6. Actuator assembly according to claim 5, wherein the two further pole shoe elements (13, 14) are provided as magnetically anisotropic pole shoe elements.

7. Actuator assembly according to at least one of the preceding claims, wherein the actuator element (1) is formed as a rod-shaped actuator element which has a greater extent along a longitudinal direction (2) which runs in the second direction than in a transverse direction which runs in the first direction.

8. Actuator assembly according to at least one of the preceding claims, wherein the first flux generating device (5) and the second flux generating device (6) each comprise at least two flux generating elements (7a, 7b, 7c, 7d, 8a, 8b, 8c, 8d, 18a, 18b).

9. Actuator assembly according to claim 8, wherein the first flux generating device (5) and the second flux generating device (6) are each formed with at least two coils (7a, 7b, 8a, 8b) as flux generating elements.

10. Actuator assembly according to claim 8, wherein - the first flux generating device (5) is formed with at least two coils (7a, 7b) as flux generating elements, and - the second flux generating device (6) is formed with at least two permanent magnets (18a, 18b) as flux generating elements.

11. Actuator assembly according to at least one of claims 1 to 7, wherein the first flux generating device (5) and the second flux generating device (6) each comprise a flux generating element which is formed with a coil (7a, 8a), wherein the first flux generating device (5) is configured to generate the first magnetic flux and the second flux generating device (6) is configured to generate the second magnetic flux.

12. Actuator assembly according to at least one of the preceding claims with a biasing device (19) assigned to the first flux generating device (5) or the second flux generating device (6), which is configured to provide as magnetic bias a magnetic flux corresponding to an operation of the first flux generating device (5), or the second flux generating device (6), respectively, when the first flux generating device (5) and the second flux generating device (6) are not in operation.

13. Actuator assembly according to claim 12, wherein a direction of the magnetic bias provided by means of the biasing device (19) is adjustable by means of the first flux generating device (5) and / or the second flux generating device (6).

14. Method for operating an actuator assembly, comprising the steps: - providing the actuator assembly according to at least one of the preceding claims; - controlling the first flux generating device (5) and / or the second flux generating device (6) for generating the first magnetic flux penetrating the actuator element (1) in the first direction, such that the actuator element (1) assumes a first shape; and - controlling the first flux generating device (5) and / or the second flux generating device (6) for generating the second magnetic flux penetrating the actuator element (1) in the second direction, such that the actuator element (1) assumes a second shape which is different from the first shape.