Magnetic actuating device

Abstract

In a magnetic actuator (1), a housing (2) is provided, and a piston rod (5) is provided which is movable between two end positions along the longitudinal axis of the housing (2). The piston rod (5) has at least one piston (10), and the at least one piston (10) extends radially from the piston rod (5) and is made of a ferromagnetic material or at least partially includes such a material. Further, at least one magnetic system (12) fixed to the housing is provided, and the piston (10) and the magnetic system (12) form at least one fluid gap system (14) having an axially variable fluid gap (15). Each of the fluid gaps has at least one fluid supply (16) open for adding a working fluid, and by adding a working fluid at least between the piston (10) and the magnetic system (12), the piston rod (5) can be moved to its end position.

Description

Technical Field

[0001] The present disclosure relates to a magnetic actuator including a piston rod disposed within a housing and a piston attached to the piston rod, wherein the piston rod can be moved to and held at its end position with the assistance of a working fluid and a magnetic system.

Background Art

[0002] DE 197 12 293 A1 discloses an electromagnetic actuating actuator having two magnetic systems which are arranged at a distance from each other and each have an exciting coil. An armature disk firmly connected to a shaft is arranged between the two magnetic systems. The armature disk is arranged between two springs acting in opposite directions and can be moved to two switching positions by the magnetic systems. One of the magnetic systems is assigned a permanent magnet polarized in the moving direction of the armature, which stabilizes the armature in one switching position when no current is applied. When the armature is to be held in the other switching position, a permanent current is required.

[0003] Furthermore, an electromagnetic linear motor is known from EP 0 568 028 A1, which is composed of an armature, two inner pole shoes, two outer pole shoes, two permanent magnets, and a coil. The armature, together with the inner and outer pole shoes, forms an air-gap system having four magnetic air gaps. The four magnetic air gaps can be varied axially and are of equal size at the central position. The permanent magnets stabilize the armature at the central position when no current is flowing through the coil. The pole shoes have the form of half-shells and, together with the permanent magnets of the half-shells, form two magnetic systems with fixed poles.

[0004] An electromagnetic lifting magnet for achieving a high holding force at a stable end position is known from DE 102 07 828 B4. This consists of a stator having two axially spaced magnetic systems, each of which has an exciting coil for generating an electromagnetic magnetic flux. An armature holds a permanent magnet assembly polarized in a direction perpendicular to the direction of movement in order to permanently hold the armature even when no current is flowing through the exciting coil, and is guided between the two magnetic systems. The permanent magnet assembly is arranged between the two exciting coils, whereby its effectiveness is reduced due to leakage magnetic flux. Furthermore, the permanent magnet assembly, which is usually made of a brittle material, can be damaged by the impact movement of the armature.

[0005] DE 10 2013 102 400 A1 discloses an electromagnetic actuator comprising a housing and an armature movable between two end positions within the housing, said armature having two armature disks and an armature shaft arranged at a distance from each other. An arrangement of two ring-shaped permanent magnets polarized in the same direction in the radial direction with respect to the axis is arranged between the armature disks and is not removable from the housing, forming two magnetic systems and one air gap system with a plurality of axially adjustable air gaps. A ring-shaped coil connectable to a power supply is arranged between the two permanent magnets. The magnetic systems and the air gap system are arranged such that the armature can be held at each of the two end positions without exciting the coil, and the armature can be moved from one end position to the opposite end position by exciting the coil.

[0006] A sensor and an actuator for a double stabilizer are known from DE 10 2016 105 000 A1, which comprises an armature unit arranged in a housing and consisting of a disk-shaped permanent magnet body and a striker unit attached thereto. The armature unit can be axially moved by pneumatic drive means to a stable end position within the housing.

[0007] Well-known actuators are often used to operate a tool clamping jig within a motor spindle driven hydraulically or pneumatically.

[0008] The present invention is based on the problem of providing an actuator that has a holding force sufficient to stably hold the actuator in its end position and can be actuated (started up) quickly.

Summary of the Invention

[0009] This problem is solved by the features of claim 1. Preferred embodiments are described in the dependent claims.

[0010] That is, the problem is solved according to the present invention, which is a magnetic actuator comprising a housing, a piston rod movable between two end positions along the longitudinal axis of the housing, and at least one magnetic system fixed to the housing. The piston rod has at least one piston, and the at least one piston extends radially from the piston rod and is made of a ferromagnetic material or at least partially surrounds such a material. The piston and the magnetic system (particularly the housing) form at least one fluid gap system having an axially variable fluid gap, and at least one fluid supply for adding a working fluid opens into the fluid gap. The magnetic actuator is characterized in that the piston rod can be actuated by adding at least the working fluid. In particular, the housing can form at least one fluid gap system having an axially variable fluid gap, at least one fluid supply for adding a working fluid can communicate with each of the fluid gaps, and the piston rod can be moved to its end position by adding a working fluid between at least the piston and the magnetic system (particularly the housing).

[0011] It may be advantageous if the piston rod has two pistons, the two pistons are arranged at a distance from each other, extend radially from the piston rod, and are made of a ferromagnetic material or at least partially surround such a material in some regions. In this embodiment, the magnetic system can be arranged in a fixed manner on the housing, particularly between the pistons.

[0012] However, the actuator may also comprise two magnetic systems fixed to the housing, between which only one piston can be moved, and each of the magnetic systems may define the end position of the piston. One or more magnetic systems may form part of the housing or may be integrated into part of the housing. Further, a magnet carrier for holding the magnetic system may be provided. One or more magnetic systems form at least one surface of the fluid gap system, either alone or in combination with other housing parts or magnet carriers. The at least one surface faces at least one surface of the piston. At least one surface of the piston also forms at least one surface of the fluid gap system. For the purposes of the present invention, the end position of the piston rod corresponds to the end position of one or more pistons.

[0013] In particular, the present invention relates to a magnetic actuator, the magnetic actuator comprising a housing, a piston rod movable between two end positions along the longitudinal axis of the housing, and at least one magnetic system fixed to the housing, the piston rod having two pistons, the two pistons being arranged at a distance from each other, extending radially from the piston rod and made of a ferromagnetic material, the at least one magnetic system being arranged between the two pistons, the piston and the magnetic system forming a fluid gap system having an axially variable fluid gap, and at least one fluid supply for adding a working fluid to each of the fluid gaps, and by adding a working fluid at least between the piston and the magnetic system, the piston rod can be moved to its end position and held there by the system.

[0014] In a preferred embodiment, the present invention relates to a magneto-pneumatic actuator, the magneto-pneumatic actuator comprising a housing, a piston rod movable between two end positions along the longitudinal axis of the housing, and at least one magnetic system fixed to the housing, the piston rod having two pistons, the two pistons being arranged at a distance from each other, extending radially from the piston rod and made of ferromagnetic material, the at least one magnetic system being arranged between the two pistons, the pistons and the magnetic system forming a fluid gap system (in particular an air gap system) having an axially variable fluid gap (in particular an air gap), at least one fluid supply (in particular an air supply) for adding a working fluid (in particular working air) opening (communicating) into each of the fluid gaps (in particular air gaps), and by adding a working fluid (in particular working air) at least between the piston and the magnetic system, the piston rod can be moved to its end position and held there by the system. Using compressed air as the working fluid has the advantage that existing resources can be utilized, and thus existing compressed air connections can be utilized.

[0015] The actuator according to the invention combines the force acting on the piston by the working fluid and the magnetic force, whereby an increase in the piston force can be achieved and the pistons can be stably held in their end positions by the magnetic system. To move the piston, one of the fluid gaps is filled with fluid, preferably under high pressure, whereby the piston moves from its (previous) end position to the opposite end position. When the piston is moved in the direction of the magnetic system, a magnetic attraction force acts on the piston when the piston is at a predetermined distance from the magnetic system, and the movement of the piston caused by the fluid is supported by the magnetic attraction force. The piston is stably held in its end position by the magnetic system. Since the piston rod can be moved in opposite bidirectional directions by the forces acting on both pistons, the actuator is effective for said bidirectional movement.

[0016] The present invention is superior to the prior art in that the piston can be stably held at both end positions. By injecting fluid preferably into both fluid gaps, high-speed movement of the piston can be achieved. Since the operating device can utilize existing resources, it contributes to low cost and miniaturization. Furthermore, a magnetic system provided with magnetic components can be surely embedded in a housing and thus can be protected from dynamic forces.

[0017] In one embodiment, the magnetic system has a ring-shaped arrangement of one or more permanent magnets polarized in the same direction in the radial direction. For example, magnets made of a highly sensitive magnetic material such as a composite material can be used, enabling a high polarization value and magnetic field strength. The permanent magnet (arrangement) can advantageously be composed of a plurality of individual magnets arranged in a ring shape, or can be made in the form of one ring-shaped magnet. In a preferred embodiment of the present invention, the magnetic system is designed to be rotationally symmetric. However, different forms are also possible. Shapes such as ring shape, angular shape (polygonal shape), etc. are also possible. The magnetic system may be formed in a discontinuous ring shape (in this case, it is not rotationally symmetric strictly).

[0018] The magnetic system may include a configuration of pole pieces on the radially inner side and / or radially outer side made of a magnetic flux conducting material. The pole pieces can surround the permanent magnets, thereby protecting the permanent magnets from dynamic use. The inner and outer pole pieces can be composed of a soft magnetic material configuration and can be in a closed ring shape.

[0019] In one embodiment, the magnetic system has a coil, particularly a ring-shaped coil. The coil can be associated with the magnetic system and connected to a power source. Depending on the corresponding form of the coil, magnetic repulsion or magnetic attraction of the piston can be achieved. It can be advantageous when the coil is used in combination with a permanent magnet or when used alone within the magnetic system.

[0020] Aspects can also be presented where the coil is designed in a ring shape and is adjacent to (sandwiched between) permanent magnets on both sides. A magnetic system having a permanent magnet and a coil can be designed such that the piston can be fixed at an end position in or near the magnetic system without exciting the coil, and by exciting the coil, the piston can be moved from an end position on one side to an end position on the opposite side. This movement triggered by the excitation of the coil is further amplified by the pressure applied to the piston surface by the added fluid, increasing the force acting on the piston and enabling the displacement of the piston rod to occur at high speed.

[0021] Depending on the method of using the actuator device, the piston rod can be designed to have a hollow structure and accommodate an actuator device that penetrates along the longitudinal axis. The axial movement of the piston rod can be used, for example, for the connection or disconnection (separation) of the actuator device with other structural components. Furthermore, the piston rod itself can be designed as an actuator device and brought into an active contact state with other structural components.

[0022] The fluid that can be introduced into the fluid gap can be a gas or a liquid. These can be various types of fluids, such as air or oil, but are not limited to these. At least one fluid supply is provided for each fluid gap to add fluid to each fluid gap. This can be used both as an inlet for the fluid and as an outlet for the added fluid, that is, the fluid supply is also designed as a fluid discharge. To increase the clock frequency, in addition to the fluid supply, it may be advantageous to provide at least one fluid discharge for each of the fluid gaps. This allows the fluid to be discharged more quickly and enables the frequency of the actuator device to be increased.

[0023] It may 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 move to one of its end positions against the spring force of the spring, or the spring or its spring force can assist the movement of the piston rod in one direction of the movement direction of the piston rod. For example, the spring can be supported within the piston rod, at one (end) at the shoulder of the piston rod and at the other (end) at the shoulder of the housing. Depending on the design of the spring, the spring can assist (bias) the piston rod in one direction or the other. The spring can be designed as a tension spring or a compression spring. It is understood that the use of multiple springs can also be considered.

[0024] In order to ensure uniform and directed movement of the piston, at least one guiding means can be provided in one embodiment to axially guide at least one piston along the longitudinal axis. Such guiding means can preferably be guide pins, which are fixed, for example, within the housing and engage within the holes of the piston.

[0025] In one embodiment of the present invention, a cascade arrangement of multiple pistons with multiple magnetic systems and multiple fluid gaps can be provided, and the pistons can reciprocate between two magnetic systems. This can increase the resulting force. Depending on the application, any number of magnetic systems and any number of fluid gap systems with any number of pistons can be connected in series.

[0026] Depending on the application and the design of the operating device, it may be advantageous for the housing to be a multi-component design. This can simplify the implementation of maintenance and the replacement of components. According to one proposal of the present invention, in order to avoid the diffusion of magnetic flux and maintain the concentration of magnetic flux on the piston, the housing is made of a non-magnetic material. It is also conceivable to use a ferromagnetic material to control the diffusion of magnetic flux.

[0027] The actuating device can be used for various applications, for example, it can be used for electric spindles, clamping of workpieces, high-speed switching of electrical contacts, etc., but is not limited thereto.

[0028] A particularly advantageous application of the actuating device according to the invention is for a motor spindle that houses an electric motor and a spindle within a spindle housing, wherein the spindle can be rotationally driven by the electric motor, the spindle has a tool holder for a tool for workpiece machining, the spindle is designed as a hollow shaft and has a clamping device for clamping a tool or a tool holder within its longitudinal bore, in which case the housing of the actuating device is directly or indirectly attached to the spindle housing, and the piston rod can be brought into an operable connection with an element of the clamping device that is axially displaceable within the longitudinal bore of the spindle, and can transmit force and movement to move the clamping device to the release position. Accordingly, the present disclosure also includes a combination of the disclosed actuating device and an electric spindle. The aforementioned advantages of the actuating device also apply equally in such use or such combination.

[0029] With the aid of the actuating device according to the invention, a sufficiently high actuating force is achieved with an appropriate size and acceptable weight in order to compress the spring clamping set of such a tool clamping device and release the clamping device. Also, according to the device of the invention, the holding force required to hold the tool clamping device in the release position can be generated with the aid of a magnetic system.

[0030] The actuating device according to the invention can use the resources of the motor spindle, for example pneumatic means, for operation. This is particularly advantageous when the fluid used is compressed air. This is because compressed air is already used for another purpose in the motor spindle. The compressed air can be used as the actuating fluid of the actuating device according to the invention.

[0031] The actuating device can advantageously be directly attached to the motor spindle. For this purpose, the actuating device can in particular have means such as a hole connection or a screw connection that enable a quick and reversible connection to the motor spindle. However, the invention also includes embodiments in which the actuating movement and the actuating force are transmitted to the motor spindle by the interaction (combination) of the actuating device with a mechanical transmission system (for example a push-pull cable), a hydraulic transmission system or a pneumatic transmission system. Thereby, the weight of the motor spindle can be kept small.

[0032] In one embodiment, the piston rod of the magnetic actuating device can have a rotary feed-through for passing one or more fluid flow paths. These flow paths can be used to ensure the supply to other components through the actuating device. The fluid flow paths can be designed to flow, for example, oil or compressed air, but are not limited thereto.

[0033] Furthermore, an aspect can be presented in which at least one magnetic system is present within the housing wall and a movable piston that moves between its two end positions interacts with at least one magnetic system at at least one of its two end positions. Also, an aspect can be presented in which a magnetic system is present within each of the two housing walls facing (opposing) the movable piston and the movable piston is held by the magnetic systems at both of its end positions. This means that in this embodiment, by applying an actuating fluid to at least the fluid gap, the piston can be moved to one of its two end positions and held there by at least one magnetic system. For this purpose, advantageously, the piston can be made at least partially of a ferromagnetic material. The magnetic system is preferably designed such that the pressure acting on the piston by the applied actuating fluid overcomes the holding force of the magnetic system and the piston can move to the opposite end position.

[0034] The invention will be explained in more detail below with reference to the embodiments of the invention shown in the drawings.

Brief Description of the Drawings

[0035]

Figure 1

[0036]

Figure 2

Embodiments for Carrying Out the Invention

[0037] FIG. 1 shows an embodiment of a magnetic operating device 1 comprising a housing 2 having a substantially cylindrical hole extending along its longitudinal axis. The longitudinal axis projects through the housing base 3 at one end and through a cover (lid) 4 attached to the housing 1 at the other end. The housing 2 contains a piston rod 5. The piston rod 5 is movably mounted in the direction of the axis and is formed as a hollow body.

[0038] In the illustrated embodiment, the housing 2 is designed with several parts. However, it may also be advantageous to essentially consist of a single part. The housing cover 4 and the housing base 3 can be connected to the housing wall by a screw connection (not shown).

[0039] The piston rod 5 is axially movably mounted along the longitudinal axis, for example via a sliding bearing bush 6. The piston rod 5 is radially supported by the housing cover 4 and a guide piece 7 arranged in the housing 2. As shown in FIG. 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.

[0040] The guide piece 7 also serves to guide an actuator 8 that passes through the guide piece 7 and the piston rod 5 and extends along the longitudinal axis. A spring 9, such as a compression spring, may be provided within the piston rod 5. For example, the first end of the spring 9 may be supported by the piston rod 5, and the second end may be supported by the guide piece 7.

[0041] The piston rod 5 has two pistons 10. These pistons 10 are arranged at intervals from each other, extend radially from the piston rod 5, and are particularly made of a ferromagnetic material. The pistons 10 have parallel side surfaces and a cylindrical circumferential surface, and the latter can be attached, for example, within a sliding bush (not shown) that can be arranged within a hole in the housing 2. The (two) pistons 10 can have different thicknesses. The connection between the piston 10 and the piston rod 5 can be designed to be reversible or irreversible. To facilitate the maintenance and disassembly of the piston 10, the piston 10 can be connected to the piston rod 5, for example, by a plug-in connection or a screw connection. The piston 10 is axially movable along the longitudinal axis together with the piston rod 5, and guide means 11, such as guide pins, which are fixed within the housing 2 and engage with the piston 10, may be provided. This ensures the uniform movement of the piston 10.

[0042] The magnetic system 12 may be arranged between the (two) pistons 10 and fixed, for example, to the housing wall. The magnetic system 12 may be composed of one or a plurality of permanent magnets polarized in the same direction in the radial direction, thus in a direction transverse to the direction of movement of the piston rod 5. The permanent magnet may be designed, for example, as a ring magnet or as an arrangement of a plurality of individual magnets polarized in the same direction. The permanent magnet may be held by a magnet carrier 13 designed as a pole piece (magnetic pole piece). The magnet carrier 13 may be composed of an inner magnet carrier and an outer magnet carrier, between which a magnetic system 11 designed as one permanent magnet may be arranged, the outer magnet carrier may be firmly fixed to the housing 2, and the inner magnet carrier may be stably supported on the sliding bearing bush 6. Other designs of permanent magnets, such as angular permanent magnets, are also possible. The pistons 10 and the magnet carrier 13 may be made of a material that conducts magnetic flux well, especially a soft magnetic material. The piston rod 5 may also be made of a material that conducts magnetic flux, but is preferably made of a non-magnetic material to prevent scattering of magnetic flux. The housing 2 is also made of a non-magnetic material.

[0043] Instead of or in addition to the permanent magnet as the magnetic system 12, at least one coil connected to a power source and having at least one winding (not shown) may be provided. The coil may be arranged, for example, between two individual magnets arranged adjacent to each other and polarized in the same direction. Further, for example, two or more magnetic systems 12 may be arranged diametrically with respect to the piston rod 5, especially with respect to the longitudinal axis, and may consist of different compositions, i.e., different combinations of permanent magnets and / or coils are possible.

[0044] A fluid gap system 14 having an axially variable fluid gap 15 is provided between a piston 10 and a magnetic system 12. At least one fluid supply 16 for adding working fluid communicates with the fluid gap 15. In one embodiment, the fluid supply 16 can also be designed as an outlet so that the working fluid is supplied or removed in a controlled manner, for example via a valve. However, in addition to the fluid supply 16, a separate fluid outlet may be provided for each fluid gap 15. In the example shown, each fluid gap 15 includes two fluid supply lines 16 that function as inlets and outlets.

[0045] To start (operate) the actuator 1, when working fluid is applied to the fluid gap 15 via the fluid supply 16, a force acts on the piston surface and the piston 10 moves. Near the magnetic system 12, the attractive force of the magnetic system 12 is also effective on the piston 10 moving in the direction of the magnetic system 12. For example, after adding a specified amount of fluid, the movement of the piston 10 stops and the piston 10 comes to rest on the magnetic system 12 and is stably held in its end position by the magnetic force. By connecting the piston 10 to the piston rod 5, the piston rod 5 also moves to the corresponding end position and, for example, in the function of the actuator 8, exerts a force on other objects by its kinetic energy.

[0046] In the actuator 1, the piston 10 can be held at two end positions on the magnetic system 12 by the magnetic force of the magnetic system 12 with a relatively large force. The intermediate position of the piston 10 where the (two) fluid gaps 15 are of equal size is unstable.

[0047] To move the piston 10 held on the magnetic system 12 to its opposite end position, the working fluid is discharged from the fluid gap 15 pre-filled with the working fluid, and the working fluid is applied to the (other) gap 17 between the magnetic system 12 and the piston 10. The force (by the working fluid) acting on the piston 10 held on the magnetic system 12 by the magnetic force moves the piston 10 against the magnetic force to its opposite end position. The movement of the piston 10 can be assisted (achieved) by applying the working fluid into the corresponding gap 17 in the vicinity of the second piston 10. This means that it is preferable that both fluid gaps 15, 17 can be simultaneously filled or emptied with the working fluid, and it is preferable that the force generated from the working fluid always acts on both pistons 10. This increases the force acting on the piston 10 and the piston rod 5.

[0048] To supply the necessary fluid to the structural components through the actuator 1, the piston rod 5 may advantageously have a rotary feed-through 18 for passing through one or more fluid flow paths.

[0049] The actuator 1 can be used, for example, when exchanging a tool on a motor spindle (not shown). The actuator 1 can be attached to the spindle housing by a cover. The end of the shaft protruding from the cover can engage in the longitudinal hole of the spindle in the design of the plunger, and in the position where the piston rod 5 is retracted into the housing, it can face the end face of the element of the clamping device, particularly the end face of the plunger of the clamping device, at a small distance. In the described position of the actuator 1, the tool holder can be clamped by the clamping device, for example, with the help of the force of a disc spring.

[0050] When the tool holder is replaced with the tool attached, after the spindle is stopped, the working fluid is applied to the fluid gap 15, the piston rod 5 is moved in the opposite direction, and at this position, the piston 10 is stably held by the magnetic system 12. The piston rod 5 has moved to a position further outside the housing 2. Here, the shaft with the plunger is moved in the direction of the clamping system against the biasing force of the disc spring to such an extent that, for example, the tool holder can be released from the clamping device and the tool taper can be released. The tool holder and the tool attached thereto can thus be removed manually or automatically. The tool cone can be attached directly to the machining tool or, alternatively, to the tool holder.

[0051] After inserting a new tool into the receptacle of the spindle, in order to clamp the new tool, the working fluid is removed from the fluid gap 15 and applied to the gap 17 between the magnetic system 12 and the piston 10 or the gap 17 between the housing wall and the piston 10. The spring 9 can assist the movement of the piston rod 5. In other words, if the spring 9 is designed as a compression spring, the piston rod 5 is moved against the spring force of the spring 9 in the direction of the housing 2 and is moved with the assistance of the spring force in the direction away from the housing 2. However, the spring 9 can also be designed as a tension spring, in which case the movement of the piston rod 5 is assisted in the opposite direction.

[0052] Figure 2 shows an embodiment of an actuating device with only one piston. For the design of the actuating device 1, reference is made to Figure 1. The actuating device 1 can be provided with only one piston 10 that is movable between two end positions and is operatively connected to the piston rod 5. At least one magnetic system 12 is present within the housing wall 2, i.e., the magnetic system 12 can be part of the housing in one embodiment. In the sense of the present invention, the magnetic system can thus be integrated, for example, within the housing wall. By means of the magnetic system 12, the piston 10 that can be moved between its end positions can interact with at least one magnetic system 12 at at least one of its two end positions. In other words, the piston 10 is moved towards one of its end positions by applying an actuating fluid to the fluid gap 15 and is held there by at least one magnetic system 12 or without any magnetic system at all. However, the magnetic system 12 can also assist in the movement of at least one piston 10, i.e., it can additionally act as a force on the piston 10 such that the movement of the piston 10 is accelerated. At the end position of at least one piston 10, the magnetic system 12 can exert a magnetic holding force on the at least one piston 10. This means, in particular, that the magnetic system can act not only as a holding force but also, in one embodiment, as an accelerating force.

[0053] An embodiment can be presented in which magnetic systems 12 are present in each of the two housing parts 3, 4 facing the moving piston 10 such that the moving piston 10 is held at both of its end positions by the magnetic systems 12. This means that the piston 10 is moved to one of its two end positions by the actuating fluid introduced into the fluid gap 15 and is held there by at least the magnetic systems 12. For embodiments in which the magnetic system 12 is not present within the housing 2 or its components (such as the housing wall), reference is made to Figure 1 above.

[0054] The piston 10 can advantageously be made of at least partly ferromagnetic material. The magnetic system 12 is preferably designed such that the pressure exerted on the piston 10 by the working fluid introduced can overcome the holding force of the magnetic system 12 and the piston 10 can move to the opposite end position. By using a coil in the magnetic system 12 or as the electromagnetic system 12 exclusively, the magnetic system 12 can be designed to be switchable. The piston 10 as the movable structure can be fixed at both end positions without exciting the coil. If the movement of the piston 10 to the opposite end position triggered by the working fluid introduced into the fluid gap 15 is to be assisted, the coil can be energized such that the piston 10 is magnetically repelled and the movement of the piston 10 is assisted. This enables the actuator to be switched quickly and easily.

[0055] The drawings illustrate the invention by way of example, and the technical-functional principles and features of FIG. 2 can be transferred to the embodiment shown in FIG. 1 and vice versa. Combinations of features schematically shown by the drawings are also covered by the teaching of the invention.

Claims

1. A magnetic actuator (1), comprising: a housing (2); a piston rod (5) movable between two end positions along the longitudinal axis of the housing (2); at least one magnetic system (12) fixed to the housing; wherein the piston rod (5) has at least one piston (10); the at least one piston (10) extends radially from the piston rod (5) and is made of a ferromagnetic material or at least partially includes such a material; the piston (10) and the magnetic system (12) form at least one fluid gap system (14) having an axially variable fluid gap (15); at least one fluid supply (16) leads to each of the fluid gaps for adding a working fluid; by adding a working fluid at least between the piston (10) and the magnetic system (12), the piston rod (5) can be moved to its end positions characterizing the magnetic actuator (1).

2. The piston rod (5) has two pistons (10); the two pistons (10) are arranged at a distance from each other, extend radially from the piston rod (5), and are made of a ferromagnetic material or have such a material in at least some regions characterizing the magnetic actuator (1) according to claim 1.

3. The magnetic system (12) is arranged between the pistons in a manner fixed to the housing characterizing the magnetic actuator (1) according to claim 2.

4. The actuator comprises two magnetic systems (12) fixed to the housing; the piston (10) can be moved between the magnetic systems; each of the magnetic systems defines an end position of the piston (10) characterizing the magnetic actuator (1) according to claim 1.

5. The magnetic system (12) is designed to be rotationally symmetric characterizing the magnetic actuator (1) according to any one of claims 1 to 4.

6. The magnetic system (12) has a circular arrangement of one or more permanently polarized permanent magnets polarized in the same radial direction characterizing the magnetic actuator (1) according to any one of claims 1 to 5.

7. The magnetic system (12) has a coil The coil is associated with the magnetic system (12) and is connectable to a power source The magnetic actuator (1) according to any one of claims 1 to 6, characterized in that.

8. The coil has a ring-shaped design and is adjacent on both sides by the permanent magnet The magnetic actuator (1) according to claim 7, characterized in that.

9. The magnetic system (12) has radially inner and / or radially outer pole pieces made of a magnetic flux conducting material The magnetic actuator (1) according to any one of claims 1 to 8, characterized in that.

10. The magnetic system (12) is part of the housing (2) The magnetic actuator (1) according to any one of claims 1 to 9, characterized in that.

11. The piston rod (5) forms a receptacle for an actuator (8) that penetrates the piston rod (5) along the longitudinal axis The magnetic actuator (1) according to any one of claims 1 to 10, characterized in that.

12. A spring (9) acts directly or indirectly on the piston rod (5) The magnetic actuator (1) according to any one of claims 1 to 11, characterized in that.

13. At least one guiding means (11) is provided to axially guide at least one piston (10) along the longitudinal axis The magnetic actuator (1) according to any one of claims 1 to 12, characterized in that.

14. The housing (2) has a multi-component design The magnetic actuator (1) according to any one of claims 1 to 13, characterized in that.

15. The piston rod (5) has a rotary feed-through (18) for the passage of one or more fluid flow paths The magnetic actuator (1) according to any one of claims 1 to 14, characterized in that.

16. The fluid supply port (16) is also designed as a fluid discharge port The magnetic actuator (1) according to any one of claims 1 to 15, characterized in that.

17. In addition to the fluid supply port (16), at least one fluid discharge port is provided in the fluid gap (15) The magnetic actuator (1) according to any one of claims 1 to 16, characterized in that.

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