EP1597743A1

EP1597743A1 - Linear magnetic drive

Info

Publication number: EP1597743A1
Application number: EP04705378A
Authority: EP
Inventors: Marcus Kampf; Carsten Protze
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2003-02-26
Filing date: 2004-01-27
Publication date: 2005-11-23
Anticipated expiration: 2024-01-27
Also published as: US7482902B2; CN1754241A; DE10309697B3; WO2004077477A1; DE502004001671D1; US20060139135A1; EP1597743B1; JP2006520517A; CN100369173C

Abstract

The invention relates to a linear magnetic drive (1) consisting of an iron core (3) and a coil (11). A yoke (10) and a constant magnet (8) are connected to a movable armature (7). When the armature is placed in a first terminal position, it is supported by magnetic forces produced by the constant magnet (8) and the yoke (10) which is used as a bridge in the iron bore.

Description

description

Magnetic linear drive

The invention relates to a magnetic linear drive with a first iron core, which passes through a first coil that can be subjected to current and has at least one magnetic gap through which a magnetic flux can pass, and with a movable armature having a first permanent magnet.

Such a magnetic linear drive is known for example from European patent application EP 0 867 903 A2. The linear drive there serves to move a contact piece of an electrical switch. A movable armature has a permanent magnet which, when energized by an electrical coil, moves in the direction of the coil due to the magnetic forces acting between the permanent magnet and the energized coil. This movement serves to switch on an interrupter unit of the circuit breaker. Spring assemblies are tensioned during the switch-on movement. In order to keep the drive in its switched-on position even after an interruption in the current flow through the coil, the permanent magnet adheres to an iron core.

The invention is based on the object of designing a magnetic linear drive of the type mentioned at the outset such that reliable positioning of the armature in an end position is made possible with a simplified construction. The object is achieved according to the invention in a magnetic linear drive of the type mentioned at the outset in that in a first end position of the armature the first permanent magnet at least partially fills a gap in the first iron core and a yoke arranged on the armature bears against an edge of a gap in the first iron core.

A magnetic flux with a low magnetic resistance can be steered within the first iron core. An iron core can consist of various suitable materials that have ferromagnetic properties (e.g. iron, cobalt, nickel, core sheets made of special alloys). The at least partial filling of a gap in the first iron core by means of a permanent magnet permits a transition of the magnetic field lines emanating from the permanent magnet into the first iron core with little loss. Because the yoke rests against the edge of a gap, the guidance of the magnetic flux is improved by the fact that the magnetic flux is also guided within the yoke. The reluctance results in a force effect. The

The effect of force is particularly great when the distance between the yoke and the iron core is as small as possible. It can be provided, on the one hand, that the gap which the permanent magnet fills and the gap at the edge of which the yoke rests are one and the same gap or are also different gaps. The magnetic flux generated within the first iron core is so strong that the armature is held in its end position. It can only be moved out by an external force or by energizing the coil.

Furthermore, it can advantageously be provided that the first iron core consists of at least two sections, between which the gap (s) is (are) formed, which (r) can be penetrated by a magnetic flux that can be generated in the first iron core.

The division of the iron core into at least two sections allows the magnetic flux to be advantageously guided inside the first iron core. For example, the iron core can be designed in one piece, the iron core itself being divided into a plurality of sections by a corresponding arrangement of cuts. The incisions are then to be regarded as gaps in which, for example, the first permanent magnet is moved with the armature. The subdivision into several sections allows specific areas on the iron core to be specifically designed, in which the magnetic flux runs in preferred directions, for example in order to be able to enter or exit perpendicular to a surface.

Furthermore, it can advantageously be provided that the first iron core is formed at least in two parts and on a first core body and on a second core body of the first

Iron core are each arranged pole faces, between which a first and a second gap are formed.

A division of the first iron core into several core bodies allows a modular assembly of the first iron core. Depending on the requirements, different iron cores can be formed from a small number of core bodies. For example, two identical core bodies can be used, between which a first and a second gap are formed. In a simple case, the two core bodies are as

U-shaped cores, the free ends of the legs being arranged opposite one another on the end face. The end faces of the legs then form the pole faces. Between A first and a second gap are formed in each case. Such an iron core is extremely robust and can be manufactured inexpensively. The legs of the u-shaped core body are suitable for receiving the first coil that can be supplied with current and for serving as attachment points of the yoke.

A further advantageous embodiment can provide that in the first end position of the armature the yoke is held by a magnetic flux emanating from the first permanent magnet.

The use of magnetic flux to hold the anchor makes mechanical latches unnecessary. This magnetic "latching" is almost free of mechanical wear. Due to the use of a permanent magnet, no auxiliary energy is required to keep the first end position of the armature permanently.

A further advantageous embodiment can provide that in the first end position a magnetic force caused by the magnetic flux acts against a force emanating from an additional element.

An additional element can be, for example, an elastic element which is tensioned in the first end position during movement of the armature. Elastic elements are, for example, springs, hydraulics, pneumatics, etc. The holding force of the armature caused by the magnetic flux is greater than the force emanating from the elastic element. The force provided by the elastic element is now available to move the armature out of the first end position. The one to initiate an outward movement The external force required for the armature from the first ^' end position only has to have an amount which is greater than the difference between the magnetic force and the force emanating from the elastic element. The external force can be generated, for example, by energizing the electrical coil. Such a construction makes it possible, regardless of the magnitudes of the magnetic force or the force emanating from the elastic element, to cause the armature to move from the first end position with a relatively small external force which only depends on the force difference. The force necessary for the complete movement of the armature is provided by the elastic element. For example, even for magnetic linear drives of very high power, only low external breaking forces are necessary.

Furthermore, it can advantageously be provided that a magnetic field can be generated with the first coil, which passes through the gap transversely to the direction of movement of the armature.

A magnetic field oriented transversely to the direction of movement of the armature can be generated, for example, by winding the coil onto a leg of a U-shaped core body. This makes it very easy to replace the coil itself and the effect of the magnetic field generated by the first coil is directly enhanced by the iron core. It can also be provided, for example, that the coil extends on two opposite sides of a gap in the iron core. This creates a symmetrical force effect on the gap or on the permanent magnet. The magnetic field in the gap can preferably run perpendicular to the direction of movement of the armature. A further embodiment can advantageously provide that the armature has a second permanent magnet which interacts with a second iron core which is penetrated by a second current-carrying coil and which has at least one magnetic gap which can be penetrated by a magnetic flux, a magnetic gap of the second iron core in a second end position of the armature is at least partially filled by the second permanent magnet and the yoke bears against an edge of a magnetic gap of the second iron core.

By using an armature with two permanent magnets and a yoke, it is possible to hold the armature securely in two end positions. The magnetic flux generated by the first or by the second permanent magnet can be used to provide the holding forces. Furthermore, the use of the first and the second coil enables the forces available for moving the armature to be amplified in a simple manner. Depending on the winding direction and direction of energization of the two coils, one or both coils can produce a force effect on the armature. Depending on the design, it is possible to increase the drive power or to generate the same drive power with two smaller coils as with a single coil. Furthermore, it is possible to do without the elastic elements which provide a restoring force. However, it can also be provided that elastic elements continue to be used, for example in order to bring about an emergency switching capacity or braking or additional acceleration of the armature.

Furthermore, it can advantageously be provided that the yoke in the first end position at an edge of a gap of the first Iron core and in the second end position on one edge of a

Gap of the second iron core is present.

In addition to the generation of the holding forces in the first end position and in the second end position, the yoke on the first iron core and on the second iron core serves as a mechanical stop. This limits the distance of the armature. The yoke can be designed with sufficient mechanical stability to absorb the impact and impact forces. The iron cores and the yoke are mechanically stable as load-bearing elements and keep vibrations away from the coils.

Furthermore, it can advantageously be provided that a drive having the features according to one of claims 1 to 6 is constructed mirror-symmetrically to a mirror axis.

A mirror-symmetrical design allows the drive to be built up in a modular manner and modules of the same type used in the process. The mirror axis can, for example, be parallel or congruent with the movement axis of the linearly displaceable armature. Another advantageous mirror axis can be, for example, an axis perpendicular to the direction of movement of the armature. With such a shape, it is possible to design the first and the second iron core in the same way. This makes it possible to manufacture drives of various shapes with just a few components.

In the following, the invention is shown schematically on the basis of an exemplary embodiment in a drawing and described in more detail below.

The shows Figure 1 shows a first variant of a magnetic linear drive in a first switching position

Figure 2 shows the first variant of a magnetic linear drive in a second switching position

Figure 3 shows a modification of the first variant of a magnetic linear drive, the

Figure 4 shows a magnetic linear drive in a second variant in a first switching position

5 shows the second variant of a magnetic linear drive at the beginning of the transfer from the first

Switch position in a second switch position and the

Figure 6 shows a modification of the first variant of a magnetic linear drive with another

Yoke.

FIG. 1 shows a first embodiment variant of a magnetic linear drive 1. The magnetic linear drive 1 is used to move a switching contact of an electrical switching device 2. The electrical switching device 2 can, for example, be a multi-pole circuit breaker which has vacuum holding tubes. The magnetic linear drive 1 has a first iron core 3. The first iron core 3 has a first core body 3a and a second core body 3b. The first core body 3a and the second core body 3b are configured in the same way. The core bodies 3a, 3b are designed as U-shaped core bodies and are arranged one another that the free leg of the core body

3a, 3b are arranged opposite one another on the end face. The first core body 3a has a first leg 4a and a second leg 4b. The second core body 3b has a first leg 4c and a second leg 4d. The end faces of the first legs 4a, 4c are designed as pole faces and delimit a first gap 5. A second gap 6 is formed on the end faces of the second legs 4b, 4d between their pole faces. An armature 7 can be moved between the first gap 5 and the second gap 6. The armature 7 has a first permanent magnet 8. The north and south poles (NS) of the first permanent magnet 8 are arranged such that the field lines 9 running inside the first permanent magnet 8 can pass almost perpendicularly into the pole faces of the first legs 4a, 4c and the second legs 4b, 4d. The armature 7 also has a yoke 10. The yoke 10 is fastened at a distance from the first permanent magnet 8 on a side of the armature 7 facing away from the switching device 2. The connection of the first permanent magnet 8 to the yoke 10 is formed from a non-magnetic material. The second legs 4b, d serve as a winding core for a first coil 11. Alternatively, it can also be provided that the first coil 11 is wound on the first legs 4a, 4c. The first coil 11 extends on both sides of the axis of movement of the armature 7. A spring assembly 12a, b is arranged on the first iron core 3 as an elastic element and can be compressed when the armature 7 moves.

1 shows the magnetic linear drive 1 in the

Off position, ie the electrical switching device 2 has open contacts. The armature 7 is held stably in its off position via the prestressed spring assembly 12a, b. From- Position defines a second end position of the armature 7. The first permanent magnet 8 bridges the second gap 6 and fills it. When the first coil 11 is energized in a first direction (13) with direct current, the force between the magnetic field of the first causes it

Permanent magnet 8 and the magnetic field of the first coil 11 a movement of the armature 7 in the direction of the first gap 5.

An additional force effect is generated during the movement by reducing the distance between the yoke 10 and the first iron core 3.

FIG. 2 shows the first end position of the armature 7, in which the first permanent magnet 8 bridges the first gap 5. The contacts of the electrical switching device 2 are now closed. The spring assembly 12a, b is tensioned. The yoke 10 lies flat against the edge of the second gap 6. The yoke 10 bridges the second gap 6. The magnetic flux 15 emanating from the first permanent magnet 8 is now conducted in the first core body 3a and the second core body 3b and is closed via the yoke 10. The magnetic force caused by the first permanent magnet 8 holds the armature 7 stable in the first end position. The magnetic linear drive 1 acts as a drive which is fed by a permanent magnet.

To move the armature 7 from the first end position (FIG. 2) to a second end position (FIG. 1), energization of the first coil in a second direction 14 is necessary. Alternatively, it can be provided that an additional coil is used to effect an opening movement. For example, a special movement sequence of the armature 7 can be brought about during a switch-off process. Supported by the tensioned spring assembly 12a, b first permanent magnet 8 is moved out of the first end position. With it also move the anchor 7 and that

Yoke 10.

In the first end position (FIG. 2), the armature 7 is held stable by the magnetic flux emanating from the first permanent magnet 8. In the second end position (FIG. 1), the armature 7 is held stable by the spring assembly 12a, b.

FIG. 3 shows a modification of the variant of a magnetic linear drive shown in FIGS. 1 and 2. FIG. 3 shows a magnetic linear drive 1 a, which has an integral first iron core 3. The first iron core 3 is U-shaped. A first coil 11 is wound on one of the legs. A first gap 5 is formed between the pole faces located on the face of the first leg 4a and the second leg 4b. A first permanent magnet 8 can be moved within the first gap 5. The first permanent magnet 8 is arranged on an armature 7. A yoke 10 is also assigned to the armature 7. After the armature 7 has moved into a first end position (not shown), the yoke 10 is supported on the second leg 4b. The second leg 4b forms an edge of the first gap 5. The flat contact of the yoke 10 shortens the path of the field lines emanating from the first permanent magnet 8 via the first iron core 3 and the yoke 10, so that the armature 7 due to the magnetic force effect of the permanent magnet 8 is kept stable in the first end position. To transfer the armature 7 from the second end position into the first end position and vice versa, the first coil 11 is to be energized with opposite current directions. The mode of operation of the arrangement shown in FIG. 3 corresponds to the mode of operation of the magnetic linear drive shown in FIGS. 1 and 2 and described above.

FIG. 6 shows a magnetic linear drive as it is known in principle from FIG. 3. In addition to the yoke 10, the armature 7 has a further yoke 10a. The yokes 10, 10a serve to stably support the armature 7 in the end positions.

Figures 4 and 5 show a second variant of a linear drive according to the invention. A double magnetic linear drive 20 shown in FIGS. 4 and 5 has a first iron core 21 and a second iron core 22, each with two core bodies. The configuration of the first iron core 21 and the second iron core 22 corresponds to the configuration of the iron core shown in FIGS. 1 and 2. A first coil 23 is assigned to the first iron core 21. A second coil 24 is assigned to the second iron core 22. The first coil 23 and the second coil 24 are arranged on free legs of the iron cores. The double magnetic linear drive 20 has an armature 25. A yoke 26 is attached to the center of the armature 25. The armature 25 is linearly stretched and has at its ends a first permanent magnet 27 and a second permanent magnet 28. The first iron core 21, the first coil 23 and the first permanent magnet 27 act in the same way as the second iron core 22, the second coil 24 and the second

Permanent magnet 28 together (as described above for Figures 1 and 2). Because of the mirror image with respect to its axis of symmetry 29 and the shape The armature 25 can be used to transfer the armature 25 from a first end position to a second end position and vice versa both the first and the second coil 23, 24. Just as described for FIG. 1 and FIG. 2, the yoke 26 acts as a bridge to a gap of the first iron core 21 or the second iron core 22 and positions the armature 25 in its end positions using those caused by the respective permanent magnets 27, 28 magnetic holding forces. Expressed in simple terms, the spring assembly 12a, b provided in FIGS. 1 and 2 to produce a restoring movement was replaced by an arrangement with a second iron core 22, a second coils and a second permanent magnet 28.

All features of those shown in the figures

Design examples can be combined with each other, so that further variations arise.

Claims

claims

1. Magnetic linear drive (1.20) with a first iron core (3.21) which passes through a first current-carrying coil (11.23) and has at least one magnetic gap (5) penetrable by a magnetic flux and with a first permanent magnet (8,27) having movable armature (7,25), wherein in a first end position of the armature (7,25) the first permanent magnet (8,27) at least partially fills a gap of the first iron core (3,21) and on the yoke (10, 26) arranged on the armature (7, 25) bears against an edge of a gap in the first iron core (3, 21).

2. Magnetic linear drive (1.20) according to claim 1, characterized in that the first iron core (3,21) consists of at least two sections, between which the gap (s) is / are formed, which (r) of one in the first iron core

(3,21) generated magnetic flux is enforceable

(are) .

3. Magnetic linear drive (1.20) according to claim 2, characterized in that the first iron core (3,21) is formed at least in two parts and on a first core body (3a) and on a second core body (3b) of the first iron core (3) pole faces are arranged between which a first and a second gap (5, 6) are formed.

4. Magnetic linear drive (1.20) according to one of claims 1 to 3, characterized in that in the first end position of the armature (7.25) the yoke

(10,26) by one of the first permanent magnet

(8.27) outgoing magnetic flux is held.

5. Magnetic linear drive (1, 20) according to claim 4, so that a magnetic force caused by the magnetic flux acts against a force emanating from an additional element (12a, b) in the first end position.

6. Magnetic linear drive (1.20) according to one of claims 1 to 5, characterized in that with the first coil (11,23) a magnetic field can be generated, which the gap (5,6) transverse to the direction of movement of the armature (7th , 25) enforced.

7. Magnetic linear drive (20) according to one of claims 1 to 6, characterized in that the armature (25) has a second permanent magnet (28) which cooperates with a second coil (24) penetrated by a second iron core (22) which acts on has at least one magnetic gap that can be penetrated by a magnetic flux, a magnetic gap of the second iron core (22) being at least partially filled by the second permanent magnet (28) in a second end position of the armature (25) and the yoke (26) on abuts an edge of a magnetic gap of the second iron core (22).

8. Magnetic linear drive (20) according to claim 7, characterized in that the yoke (26) in the first end position at an edge of a gap of the first iron core (21) and in the second end position at an edge of a gap of the second iron core ( 22) is present.

9. Magnetic linear drive (20) according to one of claims 7 or 8, d a d u r c h g e k e n z e i c h n e t that a drive having the features according to one of claims 1 to 6 is mirror-symmetrical to a mirror axis.