Magnetic actuating device

Abstract

Disclosed is a magnetic actuating device (1), comprising a housing (2) and a piston rod (5) that is movable along a longitudinal axis of the housing (2) between two end positions, said piston rod having at least one piston (10) which extends radially from the piston rod (5) and which consists of a ferromagnetic material or comprises a ferromagnetic material at least in parts. At least one magnet system (12) that is fixed with respect to the housing is also disclosed, wherein the piston (10) and the magnet system (12) form at least one fluid gap system (14) with axially variable fluid gaps (15), into each of which at least one fluid supply (16) opens for the purposes of introducing actuating fluid, such that the piston rod (5) is movable into its end positions at least by the introduction of actuating fluid between the piston (10) and the magnet system (12).

Description

[0001] MAGNETIC ACTUATOR

[0002] The invention relates to a magnetic actuating device with a piston rod located in a housing and a piston arranged thereon, which can be moved into its end position and held there by an actuating fluid and the assistance of a magnet system.

[0003] DE 197 12 293 A1 discloses an electromagnetically operating actuating device with two spaced-apart magnet systems, each with an excitation coil, between which an armature disk is rigidly connected to an actuating shaft. The armature disk is located between two opposing springs and can be moved into two switching positions by the magnet systems. A permanent magnet polarized in the direction of movement of the armature is assigned to one of the magnet systems, which stabilizes the armature in one switching position when de-energized. If the armature is to be held in the other switching position, a continuous current supply is required.

[0004] Furthermore, EP 0 568 028 A1 discloses an electromagnetic linear motor consisting of an armature, two inner pole pieces, two outer pole pieces, two permanent magnets, and a coil. The armature, together with the inner and outer pole pieces, forms an air gap system consisting of four axially variable magnetic air gaps that are equal in size in the center position. The permanent magnets stabilize the armature in the center position when the coil is de-energized. The pole pieces are half-shell-shaped and, together with the half-shell-shaped permanent magnets, form two fixed-pole magnetic systems.

[0005] An electromagnetic solenoid for achieving high holding forces in the stable end positions is known from DE 102 07 828 B4. It consists of a stator with two axially spaced magnet systems, each with an excitation winding for generating an electromagnetic flux. An armature is guided between the two magnet systems, which carries a permanent magnet arrangement polarized perpendicular to its direction of movement to permanently hold the armature without energizing the excitation winding. The permanent magnet arrangement is located between the two excitation windings, which impairs its effectiveness due to stray flux. Furthermore, the usually brittle material of the permanent magnet arrangement can suffer from jerky movement of the armature.

[0006] DE 10 2013 102 400 A1 describes an electromagnetic actuating device with a housing, an armature movable within the housing between two end positions, which armature has two spaced-apart armature disks and an armature shaft. Two annular arrangements of permanent magnets polarized radially in the same direction to the axis are arranged fixedly within the housing between the armature disks and together form two magnet systems and an air gap system with axially variable air gaps. An annular coil connectable to a power source is arranged between the two permanent magnets. The magnet systems and the air gap system are designed such that the armature can be held in each of the two end positions without energizing the coil and can be moved from one end position to the opposite end position by energizing the coil.

[0007] DE 10 2016 105 000 A1 discloses a bistable sensor and actuator device comprising an armature unit arranged in a housing, consisting of a disc-shaped permanent magnet body and a plunger unit mounted thereon. The armature unit can be moved axially into its stable end positions within the housing by pneumatic drive means. Known actuators are often used to actuate tool clamping devices in hydraulically or pneumatically driven motor spindles.

[0008] The invention is based on the object of providing an actuating device which has sufficient holding forces to keep the actuating device stable in its end positions and which can be switched quickly.

[0009] The object is achieved by the features of claim 1. Preferred embodiments are described in the dependent claims.

[0010] The object is achieved according to the invention in that a magnetic actuating device with a housing, a piston rod which is movable along a longitudinal axis of the housing between two end positions and which has at least one piston which extends radially from the piston rod and is made of a ferromagnetic material or at least partially encompasses this, with at least one magnet system which is fixed to the housing, wherein the piston and magnet system, or in particular the housing, form at least one fluid gap system with axially variable fluid gaps, into which at least one fluid supply for introducing actuating fluid opens, so that the piston rod can be moved into its end positions at least by introducing actuating fluid between the piston and magnet system, or in particular the housing.

[0011] It can be advantageous if the piston rod has two pistons arranged at a distance from one another and extending radially from the piston rod, said pistons being made of a ferromagnetic material or at least partially enclosing said material. In this embodiment, the magnet system fixed to the housing is arranged in particular between the pistons. However, it can also be provided that the actuating device comprises two magnet systems fixed to the housing, between which only one piston is movable and which each mark an end position of the piston. The magnet system or systems can form part of the housing or be integrated into a housing part. Magnet carriers can also be provided to carry the magnet system.The magnet system(s), either alone or in combination with other housing parts or magnet carriers, form at least one surface of the fluid gap system, which faces at least one surface of the piston, which also forms at least one surface of the fluid gap system. According to the invention, the end positions of the piston rod correspond to the end positions of the piston(s).

[0012] In particular, the invention relates to a magnetic actuating device with a housing, a piston rod which is movable along a longitudinal axis of the housing between two end positions and which has two pistons made of a ferromagnetic material which are arranged at a distance from one another and extend radially from the piston rod, with at least one magnet system which is fixed to the housing between the pistons, wherein the piston and magnet system form a fluid gap system with axially variable fluid gaps into which at least one fluid supply for introducing actuating fluid opens, so that the piston rod can be moved into its end positions at least by the introduction of actuating fluid between the piston and magnet system and can be held there by the magnet system.

[0013] In a preferred embodiment, the invention relates to a magnetopneumatic actuating device, with a housing, a piston rod which is movable along a longitudinal axis of the housing between two end positions and which has two pistons made of a ferromagnetic material which are arranged at a distance from one another and extend radially from the piston rod, with at least one magnet system which is fixed to the housing between the pistons, wherein the piston and magnet system form a fluid gap system, in particular an air gap system with axially variable fluid gaps, in particular air gaps, into which at least one fluid supply, in particular an air supply, for introducing actuating fluid, in particular actuating air opens, so that the piston rod can be moved into its end positions at least by introducing actuating fluid, in particular actuating air, between the piston and magnet system and can be held there by the magnet system.The use of compressed air as an actuating fluid has the particular advantage that existing resources can be used and thus existing compressed air connections can be used.

[0014] The actuating device according to the invention combines magnetic forces with the forces exerted on the pistons by the actuating fluid, thereby increasing the piston force and holding the pistons stable in their end positions by the magnetic system. To move the pistons, a fluid is introduced into one of the fluid gaps, preferably at high pressure, so that a piston moves from its end position to the opposite end position. Since the piston is moved in the direction of the magnetic system, a magnetic force of attraction also acts on the piston from a certain distance away from the magnetic system, so that the movement of the piston generated by the fluid is supported by the magnetic force of attraction. The piston is then held stable in its end position by the magnetic system. Because the piston rod can be moved in two opposite directions by the forces exerted on both pistons, the actuating device acts in two directions.

[0015] The invention has the advantage over the prior art in that the pistons can be securely held in both end positions. By introducing fluid, preferably into both fluid gaps, rapid piston movement can be achieved. The actuating device can utilize existing resources, which contributes to low costs and a compact design. Furthermore, the magnet system with its magnetic components is securely embedded in the housing and thus protected from dynamic stress.

[0016] In one embodiment, the magnet system comprises an annular arrangement of one permanent magnet or several permanent magnets with the same radial polarity. Magnets made of sensitive magnetic materials, such as composite materials, can be used, which enable high polarization values ​​and field strengths. The permanent magnets can advantageously consist of individual magnets arranged in a ring or can be designed in the form of a ring magnet. In a preferred embodiment of the invention, the magnet system is rotationally symmetrical. However, designs deviating from this are also possible. Shapes such as annular, square, or the like are also possible. The magnet system can also be designed as an interrupted ring, i.e., not rotationally symmetrical.

[0017] In one embodiment, the magnet system can have radially inner and / or radially outer pole bodies made of a material that conducts magnetic flux. The pole bodies can surround the permanent magnets and thus protect them from dynamic stress. In one embodiment, the inner and outer pole bodies can be made of soft magnetic material and have the shape of closed rings.

[0018] In one embodiment, the magnet system comprises a coil, in particular a ring-shaped coil, which is assigned to the magnet system and can be connected to a power source. By designing the coil accordingly, a magnetic repulsion or attraction of the pistons can be achieved. It can be advantageous if the coil is used in combination with permanent magnets or on its own in the magnet system. The coil can be ring-shaped and flanked on both sides by permanent magnets. The magnet system comprising permanent magnets and coil can be designed such that the pistons can be held in the end position on or near the magnet system without energizing the coil and can be moved from a respective end position to the opposite end position by energizing the coil.This movement triggered by the excitation of the coil is additionally amplified by the pressure exerted on the piston surface by the introduced fluid, so that the forces acting on the piston increase and the adjustment of the piston rod takes place at a high speed.

[0019] Depending on the application of the actuating device, the piston rod can be designed as a hollow body and can accommodate an actuator extending through the piston rod along its longitudinal axis. The axial movement of the piston rod can, for example, enable coupling or decoupling of the actuator with another component. However, the piston rod itself can also be designed as an actuator and can be brought into operative contact with a component.

[0020] The fluid that can be introduced into the fluid gaps can be a gas or a liquid. These can be various types of fluid, such as, but not limited to, air or oil. In order to introduce the fluid into the respective fluid gap, at least one fluid supply is provided in each fluid gap. This can serve both as the inlet for the fluid and as the outlet for the introduced fluid, so that the fluid supply is also designed as a fluid outlet. To increase the cycle frequency, it can be advantageous for there to be at least one fluid outlet in each of the fluid gaps in addition to the fluid supply. This makes it possible to discharge the fluid more quickly, so that the frequency of the actuating device can be increased. It can be advantageous for a spring to act directly or indirectly on the piston rod.Depending on the arrangement of the spring, the piston rod can either move to one of its end positions against the spring force, or the spring, or its spring force, can support the piston rod's movement in one of its directions. For example, the spring can be supported in the piston rod on one side by a shoulder on the piston rod and on the other side by a shoulder on the housing. Depending on the design of the spring, it can support the piston rod in one direction or the other. The spring can be designed as a tension or compression spring. It goes without saying that the use of multiple springs is also conceivable.

[0021] To ensure a uniform and directed movement of the pistons, one embodiment can provide at least one guide means for axially guiding at least one piston axially along the longitudinal axis. Such guide means can preferably be guide pins, which are fixed, for example, in the housing and engage in bores in the piston.

[0022] In one embodiment of the invention, a cascade-like arrangement of several pistons with several magnet systems and several fluid gaps can be provided, whereby a piston can move back and forth between two magnet systems. This can increase the resulting force. Depending on the application, any number of fluid gap systems with magnet systems and pistons can be connected in series.

[0023] Depending on the application and, consequently, the design of the actuating device, it may be advantageous for the housing to be constructed in several parts. This can simplify maintenance and any replacement of components. According to one proposal of the invention, the housing is made of a non-magnetic material to prevent magnetic flux dispersion and concentrate the flux on the pistons. It may also be provided to use a ferromagnetic material to control the dispersion.

[0024] The actuator can be used for different purposes, such as, but not limited to, with a motor spindle, clamping workpieces or quickly switching electrical contacts.

[0025] A particularly advantageous use of the adjusting device according to the invention comprises a motor spindle which contains an electric motor in a spindle housing and a spindle which can be driven in rotation by the motor and has a tool holder for a tool for machining a workpiece. The spindle is designed as a hollow shaft and has a clamping device for clamping a tool or a tool holder in its longitudinal bore. The housing of the adjusting device is directly or indirectly fastened to the spindle housing. The piston rod can be brought into operative connection with an element of the clamping device which can be axially displaced in a longitudinal bore of the spindle, transmitting a force and a movement and can move the clamping device into a release position. The present disclosure thus also encompasses the combination of a disclosed adjusting device with a motor spindle.The described advantages of the adjusting device are analogously applicable to the use or combination.

[0026] With the help of the actuating device according to the invention, sufficiently high actuating forces can be achieved, with a suitable size and acceptable weight, to compress the spring clamping sets of such tool clamping devices and release the clamping device. With the device according to the invention, the holding forces required to hold the tool clamping device in the release position can also be generated with the help of the magnetic system. The actuating device according to the invention can use resources of the motor spindle, such as any pneumatic means, for operation. This is particularly advantageous when compressed air is used as the fluid, which is already used for another purpose in the motor spindle. This compressed air can also be used as the actuating fluid in the actuating device according to the invention.

[0027] The actuating device can advantageously be attached directly to the motor spindle. For this purpose, the actuating device can, in particular, have means such as bores or screw connections that enable a quick and reversible connection to a motor spindle. However, the invention also includes embodiments in which the actuating movement and actuating force are transmitted to the motor spindle through the interaction of the actuating device with a mechanical transmission system, e.g., a push-pull cable, or through a hydraulic or pneumatic transmission system, thereby keeping the weight of the motor spindle low.

[0028] In one embodiment, the piston rod of the magnetic actuator can comprise a rotary feedthrough for one or more fluid channels. The channels can ensure the supply of additional components through the actuator. The fluid channels can be designed, for example, but not exclusively, for the passage of oil or compressed air.

[0029] Furthermore, it can be provided that at least one magnet system is present in the housing wall, so that a piston that can move between its end positions interacts with at least one magnet system in at least one of its two end positions. It can also be provided that a magnet system is present in each of the two housing walls facing the moving piston, so that the moving piston is held in both of its end positions by a magnet system. This means that in the embodiment, the piston can be moved into one of its two end positions at least by an actuating fluid introduced into the fluid gaps and can be held there at least by a magnet system. For this purpose, the piston can advantageously be made of a ferromagnetic material, at least in part.The magnetic systems are preferably designed so that the pressure acting on the piston by the introduced actuating fluid overcomes the holding forces of the magnetic system and the piston can move to the opposite end position.

[0030] The invention will be explained in more detail below with reference to an embodiment of the invention, which is illustrated in the drawing.

[0031] Figure 1 shows a first embodiment of an adjusting device with two pistons and

[0032] Figure 2 shows an embodiment of the adjusting device with a piston.

[0033] Figure 1 shows an embodiment of a magnetic actuator 1 comprising a housing 2 with a substantially cylindrical bore extending along its longitudinal axis, which projects at one end through a housing base 3 and at the other end through a cover 4 attached to the housing 1. Located within the housing 2 is a piston rod 5, movably mounted in the direction of the axis and designed as a hollow body.

[0034] In the illustrated embodiment, the housing 2 is designed in several parts. However, it may also be advantageous to construct the housing 2 essentially in one piece. The housing cover 4 and the housing base 3 can be connected to a housing wall by means of screw connections (not shown).

[0035] The piston rod 5 is mounted axially movable along its longitudinal axis, e.g., via a plain bearing bush 6. The piston rod 5 is radially supported on the housing cover 4 and a guide piece 7 arranged in the housing 2. As indicated in Figure 1, the stroke of the piston rod 5 can be defined by the design of the guide piece 7. However, this can also be achieved by other means known to those skilled in the art.

[0036] The guide piece 7 also serves to guide an actuator 8, which extends along the longitudinal axis through the guide piece 7 and the piston rod 5. A spring 9, e.g., a compression spring, can be provided in the piston rod 5, which can, for example, be supported with a first end on the piston rod 5 and with its second end on the guide piece 7.

[0037] The piston rod 5 has two pistons 10 arranged at a distance from one another and extending radially from the piston rod 5 and made in particular of a ferromagnetic material. The pistons 10 have parallel side surfaces and cylindrical outer surfaces, with which they are mounted, for example, in sliding bushings (not shown), which can be arranged in the bore of the housing 2. The pistons 10 can have different thicknesses. The connection between the piston 10 and the piston rod 5 can be reversible or irreversible. To simplify maintenance and disassembly of the pistons 10, the pistons 10 can be connected to the piston rod 5, for example, by means of plug-in or screw connections. The pistons 10 are axially movable with the piston rod 5 along the longitudinal axis, wherein guide means 11, such as guide pins, can be provided in the housing 2 and engage with the pistons 10.This ensures a uniform movement of the pistons 10.

[0038] A magnet system 12 is arranged between the pistons 10 and can be fixed, for example, to the housing wall. The magnet system 12 can consist of one permanent magnet or several permanent magnets that are polarized radially in the same direction and thus transversely to the direction of movement of the piston rod 5. The permanent magnet can be designed, for example, as a ring magnet or as an arrangement of individual magnets polarized in the same direction. The permanent magnet can be carried by magnet carriers 13 designed as pole bodies. The magnet carrier 13 can consist of an inner magnet carrier and an outer magnet carrier, between which the magnet system 11 designed as a permanent magnet is arranged, with the outer magnet carrier being firmly fixed to the housing 2 and the inner magnet carrier being firmly supported on the plain bearing bush 6. Other designs of the permanent magnets, such as square permanent magnets, are also possible.The pistons 10 and the magnet carriers 13 can be made of a material that conducts magnetic flux well, particularly a soft magnetic material. The piston rod 5 can also be made of a material that conducts magnetic flux, but it is preferably made of a non-magnetic material to counteract flux dispersion. The housing 2 is also made of a non-magnetic material.

[0039] Instead of the permanent magnet as the magnet system 12, or in addition to it, at least one coil can be provided (not shown) that can be connected to a power source and has at least one winding. The coil can, for example, be located between two flanking and co-polarized individual magnets. Furthermore, two or more magnet systems 12 can be arranged diametrically to the piston rod 5, in particular to the longitudinal axis, and can have different compositions, i.e., different combinations of permanent magnets and / or coils are possible.

[0040] Between each piston 10 and the magnet system 12, there is a fluid gap system 14 with axially variable fluid gaps 15. At least one fluid supply 16 for introducing actuating fluid opens into the fluid gaps 15. In one embodiment, the fluid supply 16 can also be designed as an outlet, so that actuating fluid is supplied or discharged in a controlled manner, for example, via a valve. However, in addition to a fluid supply 16, a separate fluid outlet can also be provided for each fluid gap 15. In the example shown, each fluid gap 15 has two fluid supplies 16, which function as a supply and an outlet.

[0041] To actuate the actuating device 1, the actuating fluid is introduced into a fluid gap 15 via the fluid supply 16, so that a force is exerted on the piston surface and the piston 10 moves. Near the magnetic system 12, an attractive force of the magnetic system 12 also acts on the piston 10, which moves in the direction of the magnetic system 12. After introducing, for example, a defined amount of fluid, the movement of the piston 10 stops and the piston 10 comes to a standstill at the magnetic system 12, where it is held stably in its end position by the magnetic force. By connecting the piston 10 to the piston rod 5, the piston rod 5 has also moved to its corresponding end position and, for example, exerts a force on another object through its kinetic energy in the function of an actuator 8.

[0042] In the actuating device 1, the pistons 10 can be held in their two end positions on the magnet system 12 with comparatively high force by the magnetic force of the magnet system 12. The center position of the pistons 10 with equally sized fluid gaps 15 is unstable.

[0043] In order to move the piston 10 held by the magnetic system 12 into its opposite end position, firstly the actuating fluid is drained from the previously filled fluid gap 15 and secondly actuating fluid is introduced into a gap 17 between the magnetic system 12 and the piston 10. The forces thereby acting on the piston 10 held by the magnetic force on the magnetic system 12 move the piston 10 against the magnetic force into its opposite end position. The movements of the piston 10 can be assisted by introducing actuating fluid into the corresponding gap 17 near the second piston 10. This means that both fluid gaps 15 can preferably be filled or emptied with actuating fluid simultaneously, so that forces emanating from the actuating fluid preferably always act on both pistons 10. This increases the forces acting on the pistons 10 and the piston rod 5.

[0044] It may be advantageous if the piston rod 5 comprises a rotary feedthrough 18 for passing through one or more fluid channels in order to supply components with necessary fluids through the actuating device 1.

[0045] The adjusting device 1 can be used, for example, for a tool change (not shown) on a motor spindle. The adjusting device 1 can be fastened to a spindle housing by means of a cover. The end of the shaft protruding from the cover can engage in the form of a plunger in a longitudinal bore in a spindle and, when the piston rod 5 is retracted into the housing, can be located at a short distance from an end face of an element of a clamping device, in particular a plunger of the clamping device. In this described position of the adjusting device 1, the tool holder can be clamped by the clamping device, for example by means of the force of disc springs.

[0046] If the tool holder with a tool attached to it is to be changed, actuating fluid is introduced into a fluid gap 15 after the spindle has been stopped, and the piston rod 5 is moved in the opposite direction, in which a piston 10 is held securely by the magnetic system 12. The piston rod 5 moves into the position further extended from the housing 2. The shaft with the plunger is moved against the force of the disc springs far enough in the direction of the clamping system that, for example, the tool holder can be released from the clamping device and the tool cone can be loosened. The tool holder and the tool attached to it can be removed manually or automatically in this way. The tool cone can be attached either directly to a machining tool or to the tool holder.

[0047] After inserting the new tool into the spindle holder, the actuating fluid is removed from one fluid gap 15 to clamp a new tool and introduced into the gap 17 between the magnet system 12 and the piston 10 or into the gap 17 between the housing wall and the piston 10. The spring 9 can support the movement of the piston rod 5. This means that if the spring 9 is designed as a compression spring, the piston rod 5 is moved against the spring force of the spring 9 towards the housing 2 and with the support of the spring force in the direction away from the housing 2. However, the spring 9 can also be designed as a tension spring, so that the movement of the piston rod 5 is supported in the opposite direction.

[0048] Figure 2 shows an embodiment of the actuating device with only one piston. With regard to the structure of the actuating device 1, reference is made to Figure 1 above. It can be provided that the actuating device 1 has only one piston 10 which is movable between two end positions and operatively connected to the piston rod 5. At least one magnet system 12 is present in the housing wall 2, i.e. the magnet system 12 can be a component of the housing in one embodiment. Within the meaning of the invention, the magnet system can thus be integrated into the housing wall, for example. Due to the magnet system 12, the piston 10, which is movable between its end positions, can interact with at least one magnet system 12 in at least one of its two end positions. This means that the piston 10 is moved towards one of its end positions by the introduction of actuating fluid into the fluid gaps 15 and is held there by at least one magnet system 12 or no magnet system 12.However, the magnet system 12 can also support the movement of the at least one piston 10, i.e., it can additionally act as a force on the piston 10, thereby accelerating the movement of the piston 10. In the end position of the at least one piston 10, the magnet system 12 can exert a magnetic holding force on the at least one piston 10. This means that, in particular, the magnet system not only functions as a holding force, but in one embodiment can also additionally act as an acceleration force.

[0049] It can be provided that a magnet system 12 is present in each of the two housing parts 3, 4 facing the moving piston 10, so that the moving piston 10 is held in both of its end positions by a magnet system 12. This means that the piston 10 is moved into one of its two end positions by an actuating fluid introduced into the fluid gaps 15 and is held there by at least one magnet system 12. Regarding the embodiment in which no magnet system 12 is present in the housing 2 or its components, e.g., the housing wall, reference is made to Figure 1 above.

[0050] The piston 10 can advantageously be made, at least in part, of a ferromagnetic material. The magnet systems 12 are preferably designed such that the pressure acting on the piston 10 by the introduced actuating fluid overcomes the holding forces of the magnet system 12, allowing the piston 10 to move to the opposite end position. By using a coil in the magnet system 12 or as an exclusively electric magnet system 12, the magnet system 12 can be designed to be switchable. The piston 10, as a mobile structure, can be held in place in both end positions without energizing the coil. If the movement of the piston 10 to the opposite end position, triggered by the actuating fluid introduced into the fluid gaps 15, is to be supported, the coil can be energized so that the piston 10 is magnetically repelled and the movement of the piston 10 is supported. This enables simple and rapid switching of the actuating device.It is noted that the figures illustrate the invention by way of example, and technical functional principles and features of Figure 2 are transferable to the embodiment of Figure 1 and vice versa. Combinations of the features schematically illustrated by the figures are also encompassed by the teaching of the invention.

Claims

PATENT CLAIMS Magnetic actuating device (1 ) with a housing (2), a piston rod (5) movable along a longitudinal axis of the housing (2) between two end positions, the piston rod having at least one piston (10) extending radially from the piston rod (5) and consisting of a ferromagnetic material or at least partially encompassing such material, with at least one magnet system (12) fixed to the housing, wherein the piston (10) and the magnet system (12) form at least one fluid gap system (14) with axially variable fluid gaps (15), into each of which at least one fluid supply (16) for introducing actuating fluid opens, so that the piston rod (5) can be moved to its end positions at least by introducing actuating fluid between the piston (10) and the magnet system (12).Magnetic actuating device (1) according to claim 1, characterized in that the piston rod (5) has two pistons (10) arranged at a distance from each other and extending radially from the piston rod (5), the pistons being made of a ferromagnetic material or at least partially encompassing such material. Magnetic actuating device (1) according to claim 2, characterized in that the magnetic system (12) is fixedly arranged between the pistons in the housing. Magnetic actuating device (1) according to claim 1, characterized in that the actuating device comprises two fixed magnetic systems (12) between which the piston (10) is movable and which each mark an end position of the piston (10). A magnetic adjusting device (1) according to any one of the preceding claims, characterized in that the magnetic system (12) is rotationally symmetrical. A magnetic adjusting device (1) according to any one of the preceding claims, characterized in that the magnetic system (12) comprises an annular arrangement of one permanent magnet or several radially polarized permanent magnets of the same direction. A magnetic adjusting device (1) according to any one of the preceding claims, characterized in that the magnetic system (12) comprises a coil associated with the magnetic system (12) and connectable to a power source. A magnetic adjusting device (1) according to claim 7, characterized in that the coil is annular and flanked on both sides by permanent magnets.A magnetic actuating device (1) according to any one of the preceding claims, characterized in that the magnetic system (12) has radially inner and / or radially outer pole bodies made of a material that conducts magnetic flux. A magnetic actuating device (1) according to any one of the preceding claims, characterized in that the magnetic system (12) is part of the housing (2). A magnetic actuating device (1) according to any one of the preceding claims, characterized in that the piston rod (5) forms a receptacle for an actuator (8) extending along the longitudinal axis through the piston rod (5). A magnetic actuating device (1) according to any one of the preceding claims, characterized in that a spring (9) acts directly or indirectly on the piston rod (5). A magnetic actuating device (1) according to any one of the preceding claims, characterized in that at least one guide means (11) is provided for axially guiding at least one piston (10) along the longitudinal axis. A magnetic actuating device (1) according to any one of the preceding claims, characterized in that the housing (2) is constructed in multiple parts. A magnetic actuating device (1) according to any one of the preceding claims, characterized in that the piston rod (5) comprises a rotary feedthrough (18) for the passage of one or more fluid channels. A magnetic actuating device (1) according to any one of the preceding claims, characterized in that the fluid supply (16) is also configured as a fluid outlet.Magnetic actuating device (1 ) according to one of the preceding claims 1 to 15, characterized in that at least one fluid outlet is provided in the fluid gaps (15) in addition to the fluid supply (16).

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