EP1859462B1 - Magnetic actuating device - Google Patents

Description

The invention relates to a magnetic actuator with a reference element, a relative to the reference element movably arranged between a first end position and a second actuator, wherein the reference element and / or the actuator comprises magnetizable material, a drive coil for generating the actuator from the first end position in the second end position moving magnetic field, a mechanical tensioning device for holding mechanical energy, with which the actuator is to be brought from the second end position to the first end position, and a fixing means having a permanent magnet for generating an actuator relative to the reference element in the second end position fixing Holding force, wherein the fixing device comprises a permanent magnet containing, separate from the actuator fixing unit.

Such a magnetic actuator is preferably used to operate a high voltage or power switch. From the EP 0 867 903 B1 Such an actuator is known. This is designed to operate a vacuum switch to interrupt a high voltage circuit. In this actuator, the actuator is moved against a restoring force of coil springs by means of an electromagnet from an open position to a closed position. In the closed position, the vacuum switch is then closed, ie a movable contact part of the vacuum switch contacts a fixed contact part of the switch. The actuator is still on a permanent magnet whose magnetic field acts in the direction of movement of the actuator. In the on position, this permanent magnetic force holds the actuator against the return action of the coil springs. The applied force from the permanent magnet is therefore very large, whereby a correspondingly large-sized permanent magnet must be attached to the actuator.

The DE 103 09 697 discloses a magnetic linear drive having an iron core and a coil. A movable armature is associated with a yoke and a permanent magnet. In a first end position of the armature, this is held due to the magnetic holding forces generated by the permanent magnet and a yoke bridging a gap in the iron core.

In another known in the prior art magnetic actuator, the actuator is held by mechanical latching in the end positions. That the mechanical latch provides a holding force in the direction of movement of the actuator. However, such a mechanical latching is not always reliable in practice and also susceptible to wear, resulting in considerable costs.

From the publication script US 2004/0164828 A1 For example, a magnetic actuator is known which has a fixing device with a permanent magnet. The permanent magnet is arranged on the reference element. The magnetic force emitted by the permanent magnet is used to hold the actuator there in an end position. Due to the proposed construction is to effect a reliable fixation of the actuator in an end position a high magnetic force needed. For a detachment of the actuator from the fixed end position is a drive coil to energize. A high magnetic force for fixing the actuator requires strong energization of the drive coil to cancel the fixation. However, a high energy requirement for the solution of the actuator from the fixed end position is undesirable.

The invention has for its object to provide a magnetic switching device with a compact designed magnetic actuator in which a fixation of the actuator in the second end position is reliably feasible and despite reliable fixation lifting the fixation with low energy consumption is possible.

This object is achieved with a generic actuator in that the reference element is coupled to the actuator via a lever arrangement which is designed to convert a force exerted by the actuator on the lever assembly in the direction of movement of the actuator force in a transversely acting force smaller amount.

By providing a separate from the actuator fixing unit with the permanent magnet, no permanent magnet must be attached to the actuator, whereby the actuator can be made much more compact. The reference element, which generally surrounds the actuator, can thus be reduced in its dimensioning accordingly. Thus, the magnetic actuator can be made more compact overall, but at the same time a fixation of the actuator in the second end position can be reliably realized.

In an advantageous embodiment, the fixing unit is arranged separately from the reference element. This allows a particularly compact design of the unit formed by the reference element and the actuator of the magnetic actuator.

In an expedient embodiment, both the reference element and the actuator have magnetizable material, in particular ferromagnetic material. Thus, the magnetic field generated by the drive coil can act both on the reference element and on the actuator for moving the actuator from the first end position to the second end position.

Advantageously, the magnetic holding force generated by the fixing device acts transversely to the direction of movement of the actuator. For a technically particularly advantageous fixation of the actuator is possible. When using a suitable power transmission device then the holding force required for fixing the actuator is then small compared a force urging the actuator from the locking position in the direction of movement of the actuator. Due to the relatively small amount of force required to hold the actuator, the fixation can be reliably realized. Also, only a correspondingly small amount of force is needed to solve the actuator from the fixation. Furthermore, by maintaining the finding no major costs, since only a relatively small holding force must be applied. Also, the low holding force hardly causes wear of the components acted upon with it, whereby the maintenance costs are reduced.

It is particularly important to ensure a reliable detection of the circuit breaker in the current flow position to avoid unnecessary power interruptions. Therefore, it is useful if in the second end position of the actuator actuated by an actuator switch establishes a conductive connection. In this second end position is thus the switch in a so-called "on-position". In addition to the "on position", only an "off position" of the switch is permitted. In the "off" position of the switch, the actuator is in the first end position spent by the mechanical tensioning device.

Furthermore, the reference element is coupled to the actuator via a lever arrangement which is designed to convert a force exerted by the actuator on the lever arrangement in the direction of movement of the actuator force into a force acting transversely thereto smaller amount. Thus, the actuator can be kept in a technically particularly simple and reliable manner by utilizing a smaller holding force in the second final setting position as compared to a restoring force applied to the actuator. This allows the deployment costs for the holding force reduce, as well as wear of the components to which the holding force attacks, largely avoid.

In a further preferred embodiment, the lever arrangement has a first lever which can be fastened rotatably to the reference element and a second lever which can be fastened rotatably to the actuator, wherein, in particular, the first lever and the second lever are connected to one another via a rotary joint. With such a lever arrangement, a technically particularly simple and reliable realization of a force transmission device of a force acting in the direction of movement of the actuator force is achieved in a smaller amount of force transverse to the direction of movement. Such a lever assembly is a lever mechanism with which a power transmission of e.g. a factor of 10 can be realized. That is, the holding force needed to hold the actuator in the intended locking position can be e.g. by a factor of 10 smaller than a voltage applied to the actuator restoring force of a return spring.

Thus, the actuator can be kept in a particularly simple manner in the intended locking position, preferably the rotary joint for connecting the lever with a magnetizable material having a retaining element is coupled. This magnetizable material may be in particular ferromagnetic material. A magnetic field provided for fixing the holding element magnetizes such a holding element and exerts a corresponding magnetic holding force thereon.

Expediently, the magnetic field emanating from the permanent magnet of the fixing device serves to fix the holding element to the fixing device, which in particular is fixed relative to the reference element. This can be on technically particularly simple and reliable way to realize the determination of the actuator in the intended position.

In order to ensure a particularly reliable and stable fixation of the retaining element on the fixing device, it is advantageous if the fixing device and the retaining element in the position in which the retaining element is fixed to the fixing device, form parts of a closed iron circle. That is, the holding member closes an open position of a magnetic iron circle. This results in one or two holding surfaces between the fixing device and the holding element. The latter increases the stability or holding force of the fixation. Preferably, a second retaining element is also provided. In this case, the two holding elements can complete an iron circle by applying them on two spaced apart iron parts, wherein one of the iron parts contains a magnetic field generating element, such as a permanent magnet. In the case of two retaining elements, this results in four retaining surfaces for the retaining elements on the fixing device formed by the iron parts, which allows a particularly stable fixation.

In a further expedient embodiment, the mechanical tensioning device comprises a return spring. Thus, in a case where power cutoff of the high voltage circuit becomes necessary, the circuit breaker can be reliably disconnected after the holding member is released from the locked position.

In order to accomplish a solution of the actuator from the locked position with minimal energy consumption, it is expedient if the fixing device continues to be a magnetic Separating coil, by means of which a counter-magnetic field can be generated, which counteracts the holding force generated by the permanent magnet. If now the counter-magnetic field is generated by means of the magnetic separating coil, then the holding force is reduced to such an extent that the force approximately exceeds a restoring spring, the holding force. As a result, the retainer moves away from the fixture. Since the strength of the holding magnetic field greatly decreases with increasing distance of the holding element from the fixing device, the magnetic separating coil can be quickly switched off again as soon as the holding element has a suitable distance from the fixing device. Thereupon, the actuator moves automatically with disconnected coil by the force of the return spring automatically in the opposite end position, in particular in the open position. Since the isolating coil only has to be operated for a short time in order to switch off the switch, only a small amount of energy is required for this, which can optionally be provided by a suitably designed capacitor.

Fig. 1

eine teilweise Schnittansicht einer erfindungsgemäßen Betätigungsvorrichtung mit einem in einer Ausschaltstellung befindlichen Stellglied,

Fig. 2

eine teilweise Schnittdarstellung der erfindungsgemäßen Betätigungsvorrichtung gemäß Fig. 1, bei der das Stellglied sich in einer Einschaltstellung befindet,

Fig. 3

eine Schnittansicht der in Fig. 1 gezeigten Betätigungsvorrichtung mit einer gegenüber der Schnittebene der Fig. 1 um 90° gedrehten Schnittebene,

Fig. 4

eine Schnittansicht der in Fig. 2 gezeigten Betätigungsvorrichtung mit einer gegenüber der Schnittebene der Fig. 2 um 90° gedrehten Schnittebene, sowie

Fig. 5

eine schematische Veranschaulichung der an einer Hebelanordnung der erfindungsgemäßen Betätigungsvorrichtung anliegenden Kräfte.

Hereinafter, an embodiment of an actuating device according to the invention will be explained in more detail with reference to the accompanying schematic drawings. It shows:

Fig. 1

a partial sectional view of an actuating device according to the invention with an actuator located in an open position,

Fig. 2

a partial sectional view of the actuator according to the invention according to Fig. 1 in which the actuator is in a closed position,

Fig. 3

a sectional view of in Fig. 1 shown actuating device with respect to the cutting plane of the Fig. 1 cutting plane rotated by 90 °,

Fig. 4

a sectional view of in Fig. 2 shown actuating device with respect to the cutting plane of the Fig. 2 90 ° rotated cutting plane, as well

Fig. 5

a schematic illustration of the applied to a lever assembly of the actuator according to the invention forces.

In the Figures 1 and 2 a magnetic actuating device according to the invention for actuating a high-voltage switch is shown in a first sectional view. It shows an electromagnetic plunger armature drive which has a reference element 1 made of ferromagnetic material designed as a stator, a magnetic drive coil 2 serving as a turn-on coil and an actuator 3 made of ferromagnetic material designed as an armature. In this case, with respect to an axis extending through a control rod 3a axis rotationally symmetrical actuator 3 within a matched to the shape of the actuator 3 recess of the reference element between a deeper in the drawing off position and a higher-lying closed position is movable back and forth.

The reference element 1 and the actuator 3 have corresponding oblique, from the magnetic flux of the drive coil 2 interspersed anchor and stator surfaces. This geometry makes it possible to optimally use the magnetic force generated by the magnetic drive coil 2, in particular with a large distance of the stator and armature surfaces to each other.

FIG. 1 shows the actuator 3 in the off position. In this position, contact elements of the actuated via the control rod 3a high-voltage switch are disconnected. The actuator 3 is made of ferromagnetic material and can by means of serving as Einschaltspule magnetic drive coil 2 in the in FIG. 2 shown switching position to be moved. In this position, a small gap between the inclined surfaces of the reference element 1 and the actuator 3 remains to prevent mechanical welding of the two elements.

When switching on two arranged respectively between the actuator 3 and the reference element 1 return springs 4 and 4 'are compressed and thus put under tension. The return springs 4 and 4 'fulfill the function of opening springs, since the force exerted by them in the closed position on the actuator 3 restoring force pushes the actuator 3 back into the open position. In this case, the return springs 4 and 4 'are dimensioned so that the acting in dependence on the auszuschaltenden from the high-voltage switch current counter gas forces can be overcome. Since the switch-off depends only on the way, it is independent of the duration of the opposing forces. Preferably, the return springs 4, 4 'are designed after the switch-off movement with maximum counterforce.

In the closed position is actuated by the control rod 3a contact element of the high voltage switch to the fixed contact element of the same, whereby the high voltage switch is closed. That in the Figures 1 and 2 interrupted rectangle is a schematic indication of one in the Figures 3 and 4 in relation to the cutting plane of the Figures 1 and 2 Fixing device 16 shown rotated by 90 °.

The in the Figures 3 and 4 Fixing device 16 shown consists of an open iron circle 5, a permanent magnet 6 and a magnetic separating coil 15. The open iron circle consists of three preferably fixed individual iron parts 5a, 5b and 5c. The first iron part 5a and the second iron part 5b are connected to each other via the permanent magnet 6, while a third iron part 5c is arranged offset upward with respect to the first two iron parts 5a and 5b. This third iron part 5c is surrounded by the magnetic separation coil.

Will now be formed of ferromagnetic material or iron holding elements 7, 7 ', as in FIG. 4 shown, applied to the lateral contact surfaces of the open iron circle 5, forms from the open iron circuit 5 and the holding elements 7 and 7 ', a closed iron circle. The magnetic field lines generated by the permanent magnet 6 now run in the closed iron circle and thus form a closed magnetic field circuit. In the present magnetic iron circle, the holding elements 7 and 7 'are held on the fixing device 16 at respectively two points, namely their respective contact surfaces with the two iron parts 5b and 5c. By dividing the permanent magnetic flux caused by the permanent magnetic holding force on four series-connected holding surfaces in the closed iron cycle is a multiple utilization of the magnetic flux, whereby the required magnetic volume can be reduced.

The two holding elements 7 and 7 'are each arranged on a lever arrangement designed as a lever arrangement 8 and 8'. The two lever arrangements 8 and 8 'each have a first lever 9 or 9' and a second lever 10 or 10 'connected thereto via a lever connection joint 13 or 13'. The first levers 9 and 9 'are each connected to the reference element 1 via a first pivot 11 or 11'. The second levers 10 and 10 'are each connected via a second pivot 12 and 12' to the actuator 3. In this case, there is the first lever assembly 8 in the in the Figures 3 and 4 shown sectional view on the left with respect to the fixing device 16 and the second lever assembly 8 'to the right thereof. The holding elements 7 and 7 'are respectively attached to the associated lever joint 13 and 13'.

Now is the actuator 3 of the in FIG. 3 shown off position by means of the magnetic drive coil 2 in the in Fig. 4 shown switching position, so move the holding elements 7 and 7 'to the fixing device 16. In the closed position, the holding elements are 7 or 7 'to the respective contact surfaces of the open iron circuit 5 and are held by the magnetic force generated by the permanent magnet 6 thereto. This magnetic holding force 14 or 14 'is sufficient to keep the actuator 3 against the restoring force of the return springs 4 and 4' in the closed position. It should be noted that due to the power transmission through the lever assembly 8 and 8 'in comparison to the force of the return springs 4 and 4' smaller holding force 14 or 14 'is sufficient. In the case of the actuating device according to the invention, the holding force 14 or 14 'can be smaller, for example by a factor of 10, than the restoring force of the restoring springs 4 or 4'.

wobei α₁ der Außenwinkel zwischen der Richtung der Kraft F2 und der Richtung des ersten Hebels 9' ist sowie α₂ der Außenwinkel zwischen der Richtung der Kraft F2 und der Richtung des zweiten Hebels 10' ist. FIG. 5 shows the power transmission through the lever assembly 8 'in the in FIG. 4 shown switched-on position. In this case, one behaves on the first pivot 12 'of the lever assembly in the direction of movement of the actuator 3 applied force F2 to a force acting on the lever joint joint 13 'perpendicular to the force F2 F1 as follows: $$\frac{F1}{F2}=\mathrm{<figure-callout\; id="1"\; label="tan\; \alpha "\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">tan\; </figure-callout>}{\alpha }_{}{}_1+\mathrm{<figure-callout\; id="2"\; label="tan\; \alpha "\; filenames="imgf0003.png"\; state="\{\{state\}\}">tan\; </figure-callout>}{\alpha }_{}{}_2$$

where α _{1 is} the external angle between the direction of the force F ₂ and the direction of the first lever 9 'and α _{2 is} the external angle between the direction of the force F ₂ and the direction of the second lever 10'.

If now the actuator 3 of the in FIG. 4 shown switching position in the in FIG. 3 shown off position, so by means of the magnetic separation coil 15, a magnetic field is generated, which is directed opposite to the magnetic field generated in the closed loop by the permanent magnet 6. Thus, the magnetic holding force 14 or 14 'is reduced such that the force exerted by the return springs 4 and 4' on the actuator restoring force is sufficient to return the actuator 3 in the off position. Due to the increasing distance between the holding elements 7, 7 'and the fixing device 16, the restoring force in the course of the turn-off even without energized separating coil 15 outweighs the holding force, so that the turn-off then alone by the return springs 4, 4' is driven. By an outer stop, not shown, and a damper, the opening movement is limited and damped.

The actuator described is an electromagnetic actuator with a large stroke, in which the Ausschaltenergie is kept in the return spring. This embodiment allows for a so-called OCO switching sequence a reduced provision of electrical energy. As shown, takes place in the closed position permanent magnetic positional fixing, whereas in the off position, a mechanical positional fixation due to the bias of the return springs. The switch-on position and the switch-off position are the only two stable positions of the actuator.

Before the OCO switching sequence, the actuator is in the closed position, whereby the energy for the first turn-off is already stored in the return springs. The power for the second cut-off is supplied to the system during start-up (return springs are cocked). For an OCO switching sequence, therefore, only the energy must be kept available for a switch-on (eg in capacitors), this energy corresponding to the energy requirement of the system for switching on and off, since the return springs are tensioned during switch-on. Compared to electromagnetic drives without mechanical energy storage, such as springs, the provision of energy for the first turn-off is saved in the actuator according to the invention.

LIST OF REFERENCE NUMBERS

1

reference element

2

magnetic drive coil

3

actuator

3a

control rod

4

first return spring

4 '

second return spring

5

open iron circle

5a

first iron part

5b

second iron part

5c

third iron part

6

permanent magnet

7

first holding element

7 '

second holding element

8th

first lever arrangement

8th'

second lever arrangement

9

first lever of the first lever arrangement

9 '

first lever of the second lever arrangement

10

second lever of the first lever arrangement

10 '

second lever of the first lever arrangement

11

first pivot of the first lever assembly

11 '

first pivot of the second lever assembly

12

second pivot of the first lever assembly

12 '

second pivot of the second lever assembly

13

Lever joint of the first lever assembly

13 '

Lever joint joint of the second lever assembly

14

Holding force on the first holding element

14 '

Holding force on the second holding element

15

magnetic separating coil

16

fixing

Claims (11)

1. Magnetic actuating device having

   - a reference element (1)

   - an actuating element (3) which is arranged such that it can move relative to the reference element (1) between a first limit position and a second limit position, with the reference element (1) and/or the actuating element (3) being composed of magnetic material,

   - a drive coil (2) for production of a magnetic field which moves the actuating element (3) from the first limit position to the second limit position,

   - a mechanical tensioning apparatus (4, 4') for storage of mechanical energy by means of which the actuating element (3) can be moved from the second limit position to the first limit position, and

   - a fixing device (16), which has a permanent magnet (6) for production of a holding force which fixes the actuating element (3) in the second limit position relative to the reference element (1),

   the fixing device (16) comprising a fixing unit (5), which contains the permanent magnet (6) and is separate from the actuating element (3),
   characterized in that
   the reference element (1) is coupled to the actuating element (3) via a lever arrangement (8, 8') which is designed to convert a force (F2) which is exerted by the actuating element (3) on the lever arrangement (8, 8') in the movement direction of the actuating element (3) to a force (F1) which acts transversely with respect to this and whose magnitude is less.
2. Magnetic actuating device according to Claim 1,
   characterized in that
   the fixing unit (5) is arranged separately from the reference element (1).
3. Magnetic actuating device according to Claim 1 or 2,
   characterized in that
   both the reference element (1) and the actuating element (3) are composed of magnetic material, in particular ferromagnetic material.
4. Magnetic actuating device according to one of the preceding claims,
   characterized in that
   the magnetic holding force produced by the fixing device (16) acts transversely with respect to the movement direction of the actuating element (3).
5. Magnetic actuating device according to one of the preceding claims,
   characterized in that,
   when the actuating element (3) is in the second limit position, a switch which is operated by the actuating element (3) produces a conductive connection.
6. Magnetic actuating device according to Claim 1,
   characterized in that
   the lever arrangement has a first lever (9, 9'), which can be attached to the reference element (1) such that it can rotate, as well as a second lever (10, 10'), which can be attached to the actuating element (3) such that it can rotate, in particular with the first lever (9, 9') and the second lever (10, 10') being connected to one another via a rotating joint (13, 13').
7. Magnetic actuating device according to Claim 6,
   characterized in that
   the rotating joint (13, 13') is coupled to a holding element (7, 7'), which is composed of a magnetic material, in order to connect the two levers (9, 9', 10, 10').
8. Magnetic actuating device according to Claim 7,
   characterized in that
   the magnetic field which originates from the permanent magnet (6) of the fixing device (16) is used to fix the holding element (7, 7') on the fixing device (16) which, in particular, is fixed relative to the reference element (1).
9. Magnetic actuating device according to Claim 7 or 8,
   characterized in that
   the fixing device (16) and the holding element (7, 7') form parts of a closed iron circuit in the position in which the holding element (7, 7') is fixed on the fixing device (16).
10. Magnetic actuating device according to one of the preceding claims,
    characterized in that
    the mechanical tensioning device (4, 4') has a reset spring.
11. Magnetic actuating device according to one of Claims 6 to 9,
    characterized in that
    the fixing device (16) also has a magnetic disconnection coil (15), by means of which an opposing magnetic field can be produced, which counteracts the holding force produced by the permanent magnet.

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