EP2474009B1 - Bistable electromagnetic actuating device - Google Patents

Description

The present invention relates to a bistable electromagnetic actuator according to the preamble of the main claim. Such a device is known from the prior art DE 103 10 448 A1 known.

Electromagnetic actuators in the form of actuators are used for a variety of control purposes, such as for the adjustment of a camshaft between different engagement positions in motor vehicles. In this case, conventional actuators, which are typically realized with a pull-in anchor, have a single stable position (setting position), in which the armature is usually held by a spring. In order to achieve a second setting position, the coil unit is subjected to a voltage application, with the effect that the spring force of the spring is overcome and the armature is moved into the second setting position. In such (monostable) actuators, the coil unit must be permanently energized to hold the anchor permanently in the second position, so that monostable solutions due to energy consumption are not or only limited for applications where the actuator is often in the second Parking position is.

Therefore, so-called bistable actuators are known from the prior art, in which the second setting position can be achieved by a time-limited (typically pulse-shaped) energization of the coil unit and then the armature in this position remains currentless (relative to the Spulenbestromung) stably. An example of such a known device shows the DE 201 14 466 U1 ,

However, in this prior art, resetting, ie, moving the armature from the second control position back to the first (home) operating position, is problematic and is caused by the external actuator (the unit to be displaced); however, this is not always possible or practicable.

In addition, there is room for improvement in terms of energy consumption in the switching process and effective switching times.

Object of the present invention is therefore to provide an electromagnetic actuator, which allows energetically favorable and with short switching times, the movement of the armature unit between the two parking positions, wherein both the movement of the armature unit from the first to the second control position, as well as the movement of the second setting position in the first position quickly, without external mechanical influence on the armature unit (by a control partner) and while minimizing switching times and energy consumption to be enabled, and wherein an additional control position is to be enabled.

The object is achieved by the bistable electromagnetic actuator with the features of the main claim; advantageous developments of the invention are described in the subclaims.

Advantageously, the (stationary) coil unit in the axial (movement) direction on both sides of the permanent magnet means associated with the armature, which act and are poled, that in response to a (impulsive, so temporally particular limited to the movement process) DC voltage signal, the armature movement in the Type of switching operation takes place. In this case, according to a preferred embodiment, a first permanent magnet of the permanent magnet means is attracted to the armature of the coil unit (according to a preferred embodiment: a magnetically effective combination of coil unit and stationary core area axially surrounding a central region of the armature), while simultaneously, opposite to the coil unit, the electromagnetic Repulsion of a second permanent magnet at the anchor takes place. Accordingly, a bistable, with regard to the switching and movement behavior symmetrical driving of the armature with optimized switching times is possible in a very effective manner.

Energetically, the coil unit is to be energized so that the repulsive effect on the permanent magnets adhering to the core region exceeds the permanent magnetic adhesive force; In addition, the permanent magnetic attraction by the (axially opposite) another permanent magnet is effective.

In a structurally particularly suitable manner, the armature unit is elongate in order to realize this basic functionality and has a central shaft section, which according to the invention extends through the coil unit or the stationary core area and at both ends realizes a permanent magnet, in each case more preferably in a disc shape. is provided with further magnetically conductive elements for flow guidance.

It is particularly preferred to form such an arrangement radially symmetrical, so that then within a cylindrical space, the adjusting device can be formed, wherein, based on a reduced diameter central shaft portion, each end ansitzenden permanent magnets are increased in diameter.

Depending on the specific requirements, such a device can be configured axially centrally or eccentrically with regard to the armature guide, and other obliquely inclined configurations are also conceivable.

According to preferred embodiments of the invention, the armature unit for realizing the engagement means frontally (one or both ends) on a preferably flat surface (anchor end face) on which then sits a plunger unit and is moved with the armature unit; this ram unit is then for cooperation with an actuator (aggregate), e.g. a camshaft for the adjustment formed.

In this connection, it is particularly favorable and preferred according to the invention to not connect such an engagement-side ram unit firmly to the anchor unit, but rather to effect a detachable connection. The present By providing the permanent magnet means, the invention makes it possible for such a metallic ram unit to be magnetically adhered to an armature end face, for example by means of the permanent-magnetic adhesive force of the permanent magnet means, insofar as a detachable connection is possible. It is also possible according to further education and provided to form a plurality of such plunger.

With regard to the concrete constructive realization and the interaction of such a tappet unit with an underlying permanent magnet, the disclosure of the German Utility Model 20 2008 008 142 of the Applicant is considered as belonging to the invention in the present application.

According further development according to the invention is intended to form the plunger unit not exclusively of magnetic or magnetically conductive material; Rather, it is useful for applications in which on the one hand the described releasable adhesion between the anchor unit and ram unit is to be achieved, on the other hand, however, the unwanted adhesion of metallic abrasion in the control range is to be avoided on the plunger unit, meaning the anchor unit opposite engagement region of the plunger unit from a not Magnetic material to be realized, which also further education according to its hardness, toughness or the like. for interaction with the engagement partner (e.g., the camshaft) can be optimized by suitable material treatment. In the context of further preferred embodiments, it is here, both sections (magnetically one hand for adhering to or on the armature end face, non-magnetic for an aggregate engagement on the other hand) to realize a permanently connected unit, in which case they particular connection methods such as sintering, friction welding or the like , to offer.

In the context of preferred developments of the invention, it is also to support the movement of the armature unit (in one or both directions of the movement longitudinal axis) by a spring action. It is preferable Such a spring (eg compression spring) to support the anchor end face at one or both ends, wherein such support both inside (ie in the movement space between the core area and permanent magnet), as well as outward (about a ram unit surrounding) can be done.

A further preferred embodiment provides for the bistable actuating device before a housing, which takes over, consisting of magnetically conductive material, tasks of the flux conduction of the magnetic flux and insofar as parallel to the longitudinal axis of movement preferably extends between the parking positions of the both sides provided on the armature unit permanent magnets.

Due to the favorable magnetic properties of the present invention, for easy assembly (and thus improve the mass production suitability) and to achieve a compact space, it is preferred to realize the housing by means of at least one bow-shaped housing element, advantageously not the housing to the entire circumference the permanent magnet means extends, but here only legs of a further preferred U (alternatively L) -shaped element are provided. If a pair of such brackets, axially aligned along respective openings for guiding the armature (more precisely, the shaft portion between the permanent magnets), then interleaved, creates an easy to install, mechanically stable and magnetically effective housing construction.

In the context of the invention, it is envisaged to form the electromagnetic actuator according to the invention as a tristable electromagnetic actuator, which is intended to fall within the scope of the invention, the term "tristable" as a special education under the general term "bistable". Specifically, it is of the invention according to a preferred embodiment comprises not (only) to realize two stable states by means of the device according to the invention, but to allow a third stable state in addition. According to training in the context of the invention, this is done by a third (preferably stable) center position along the longitudinal axis of movement of the armature unit can be taken stable by the device, more preferably in that here, too, the armature remains in this position without current (ie without current supply to the coil unit).

In a preferred embodiment, this tristability-inducing position is achieved by the fact that the permanent magnet means of the armature unit, which are advantageously provided at both ends, cooperate with a (central) stationary core area in such a way that none of the permanent magnet units adhere to the core unit by opposing attractive forces. preferably the same distance) from the core unit, with the result that the armature unit occupies the stable third setting position in the middle between the end-side setting positions.

Preferably, and within the scope of the invention, the armature unit can be moved into this third setting position by (once) pulse-shaped energization, whereby a further (one-time) pulse, in one or the other direction, is triggered by energizing pulses of corresponding polarity. Alternatively, and in practice, it has proven to be favorable to keep the stable end position either de-energized or by means of an AC signal for the coil unit (or even to reach in the first place).

The advantageous Tristabilität then allows completely new areas of application and control tasks, especially those in which then selectively an anchor unit along a longitudinal movement axis can be spent in one of three separate, each stable positions, and advantageously at least two of these, further preferably all three , are each currentless stable.

As a result, it thus makes it possible for the invention to realize a structurally simple and therefore suitable for mass production a tristable adjusting device which combines short positioning times with high energy efficiency during operation.

Fig. 1:

eine schematische Seitenansicht einer bistabilen elektromagnetischen Stellvorrichtung, wobei sich der Anker in einer ersten Stellposition links befindet;

Fig. 2:

eine Darstellung analog Fig. 1 mit ausgefahrenem Anker in die zweite Stellposition (rechts);

Fig. 3:

einen schematischen Längsschnitt durch die Vorrichtungen der Fig. 1, 2 in unbestromtem Zustand der Spuleneinheit sowie in der ersten Stellposition links;

Fig. 4:

eine Darstellung analog Fig. 3 zu Beginn der Bestromung der Spuleneinheit und vor einer Bewegung in die zweite Stellposition;

Fig. 5:

eine Perspektivansicht einer bügelförmigen Gehäuseeinheit mit einem Paar von Schenkeln;

Fig. 6:

eine Anordnung aus zwei ineinander verschachtelten Gehäusebügeln (Fig. 5) mit darin geführter Ankereinheit sowie montierter Spuleneinheit;

Fig. 7 bis Fig. 9:

verschiedene Ansichten der Ankerstirnfläche(n) der Vorrichtung gemäß Fig. 6 zum Verdeutlichen des Zusammenwirkens mit einer oder mehreren Stößeleinheiten;

Fig. 10:

eine Darstellung analog Fig. 2 mit einem Paar von beidseits axial von außen auf die Ankerstirnflächen greifenden Federn;

Fig. 11:

eine Variante eines Federeinsatzes zwischen Kernbereich und Permanentmagnet-Ankerscheibe;

Fig. 12:

ein Längsschnitt durch eine bistabile elektromagnetische Stellvorrichtung gemäß einer zweiten bevorzugten Ausführungsform, wobei in dieser Ausführungsform, zum Beschreiben einer tristabilen Funktionalität sowie einer Möglichkeit für die Ankereinheit zum Erreichen einer stabilen mittleren Stellposition, geeignete magnetische Flusspfeile eingezeichnet sind, um insoweit den stromlos stabilen Zustand (samt zugehöriger permanentmagnetischer Kraftpfeile) zu verdeutlichen, und

Fig. 13:

eine Ansicht analog der Fig. 12, jedoch mit einer zusätzlichen Bestromung der Spuleneinheit, durch welche dann das (Mitten-)gleichgewicht der Fig. 12 aufgelöst und die Ankereinheit in eine Endposition gebracht werden kann.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawings; these show in:

Fig. 1:

a schematic side view of a bistable electromagnetic actuator, wherein the armature is in a first position to the left;

Fig. 2:

a representation analog Fig. 1 with extended armature in second position (right);

3:

a schematic longitudinal section through the devices of Fig. 1, 2 in the de-energized state of the coil unit and in the first parking position on the left;

4:

a representation analog Fig. 3 at the beginning of energizing the coil unit and before moving to the second setting position;

Fig. 5:

a perspective view of a bow-shaped housing unit with a pair of legs;

Fig. 6:

an arrangement of two nested housings ( Fig. 5 ) with anchor unit guided therein and mounted coil unit;

7 to 9:

different views of the anchor end face (s) of the device according to Fig. 6 to clarify the interaction with one or more ram units;

Fig. 10:

a representation analog Fig. 2 with a pair of axially on both sides of the outside of the anchor end faces cross springs;

Fig. 11:

a variant of a spring insert between the core area and the permanent magnet armature disk;

Fig. 12:

a longitudinal section through a bistable electromagnetic actuator according to a second preferred embodiment, wherein in this embodiment, for describing a tri-stable functionality and a possibility for the armature unit to achieve a stable middle position, suitable magnetic flux arrows are drawn to the extent the normally-off state (including associated permanent magnetic force arrows) to clarify, and

Fig. 13:

a view analogous to Fig. 12 , but with an additional energization of the coil unit, through which then the (center) balance of the Fig. 12 dissolved and the anchor unit can be brought to an end position.

The FIGS. 1 to 4 illustrate the essential functional components for realizing the bistable electromagnetic actuator according to a first preferred embodiment, including sketched field progressions: An anchor unit consisting of an armature shaft 10, both permanent magnet disks 12 and 14, the permanent magnet discs each axially outwardly final armature discs 16, 18 and the permanent magnet discs 12, 14 axially inwardly delimiting inner discs 20, 22 is guided axially displaceably in a stationary core assembly 24. The core unit 24 cooperates with a coil unit 26, which (see in particular the sectional views of FIGS FIGS. 3, 4 ) is arranged surrounding the shaft portion 10. Radially shell side, the arrangement is enclosed by a stationary housing shell 30th

The bistability of this arrangement is achieved in that in a respective end state (setting position) in the axial direction of one of the permanent magnets 12, 14 (via the intermediate discs 20 and 22) adheres to the magnetic core 24; so stuck in the parking position of the FIG. 1 the right-side permanent magnet 14 on the core unit 24, while the permanent magnet 12 is axially extended. The FIG. 2 illustrates the reverse, axially shifted state of the armature (second setting position).

The FIGS. 3 and 4 clarify in this context, the effect of the permanent magnet or a Bestromungsimpulses the coil: The FIG. 3 , according to the position of FIG. 1 illustrates the permanent magnetic field of the disc-shaped permanent magnets 12, 14 (axially magnetized in the manner shown), wherein the magnetic circuit via the discs 16, 20 and 18, 22 and the enclosing housing or the shaft 10 is closed.

Upon energization of the coil unit 26 with a (pulse-shaped) DC voltage signal of a first polarity creates an additional magnetic flux, illustrated by the arrowhead 32. This, directed opposite the permanent magnetic field of the right-side permanent magnet 14, generates a repulsive force by releasing the permanent magnetic attraction to the core 24 on the anchor unit, which the anchor unit (in the figure on the right) then in the second position of the FIG. 2 drives. This effect is supported by an attractive effect between the magnetic field of the coil unit and the permanent magnetic field of the left-hand permanent magnet 12, which (see the illustration of FIGS FIGS. 3, 4 ), relative to the opposite permanent magnet, is oppositely poled in the axial direction.

The FIGS. 5, 6 illustrate how the housing 30 can be made in an elegant way from bow-shaped elements space and effort saving; more precisely, one is in the Fig. 5 shown U-shaped bracket member 34 formed of a pair of legs 36 (these extend, see the illustration of FIG. 6 , parallel to the axial direction of movement) and a central portion 38, which connects both legs 36. The central portion 38 has a central opening 39 through which the shaft portion 10 of the armature can move.

The FIG. 6 illustrates how in nested fashion a pair of housing elements 34 form the housing for the actuator and internally enclose the core or coil area 24, 26, while seated on the shaft 10 at the end, the respective disk-shaped permanent magnets with associated inner or armature disks, between the respective pairs of legs 36, can be guided to the outside.

Based on FIGS. 7 to 9 illustrates that a front-side outer surface of the armature discs 17 and 18 offers different ways to drive it rests pusher elements (ram units) 40. According to preferred embodiments, at least one plunger element 40 (alternatively also two or more, cf. FIGS. 8, 9 , where the FIG. 9 also in the opposite direction a plunger element carries) by means of magnetic adhesive force, characterized in that the plunger element 40 is held by magnetic material from the permanent magnet 12 and 14 on the respective flat face (this can be axially parallel, centric, alternatively also skewed, depending on Configuration). For further disclosure reference is made in this regard to the patent disclosure 10 2007 028 600 and the Utility Model Publication 20 2008 008 142 of the Applicant, which disclose various ways how a ram unit (releasably) can interact with a permanent magnet disc having an armature unit.

In addition, according to the development of the invention, it is provided that the elongate cylindrically shown tappet unit is formed from a plurality of axially adjoining sections; In this case, a section which engages on the outer surface of the armature disk is preferably magnetic in order to achieve the advantageous releasable adhesive effect. On the other hand, it is preferable to design an opposite free end, which cooperates with a setting partner (aggregate), such as a camshaft, in otherwise known, but not shown in the figures, of non-magnetic material. On the other hand, this has the advantage that in practical operation then no magnetic abrasion can adhere. Also, there is the possibility to harden such a range suitable or trained suitable for its intervention purpose wear-resistant. The described sections may then be suitably, e.g. via sintering, friction welding or the like. Permanently and permanently are joined together.

The FIGS. 10 and 11 illustrate ways how, building on the configuration of FIGS. 1 or 2, one or two compression springs 50, 52 (from the outside) and 54 (between the core and inner disc 20, 22) force-enhancing, damping or other otherwise known manner can be used.

The FIGS. 12 and 13 illustrate an embodiment of the present invention, wherein like reference numerals with the first embodiment in this regard denote identical or equivalent functional components.

The longitudinal section view of Fig. 12 illustrates the slightly different structural design of the armature unit, in which case the central shaft portion 10 has been supplemented in addition to permanent magnetic flux-conducting sections 60, which allow the same core side as disks 62 a Flußleitwirkung on the surrounding housing 30. In that regard, the closed thin arrowheads 66 illustrate a permanent magnetic flux in which Fig. 12 symmetrically shown holding the armature unit in a central position between both end positions, as related to the described first embodiment, allows. More specifically, two in Fig. 12 shown as thick arrows 68 permanent magnetic force arrows, as by permanent magnetic attraction of the discs 12, 14 and without energization of the coil a stable center state is reached, since, with approximately the same permanent magnetic attraction and symmetrical geometry, insofar as the mutually directed forces 68 neutralize. This intermediate state can be achieved by a pulse-shaped temporary energizing of the coil unit so as to bring the armature unit into this state, wherein the energizing is terminated before a stop takes place at the opposite end.

Building on the geometry of the Fig. 12 illustrates the now possible energization, as by a pulse and arrow 70, a repulsive effect in the left - side area is generated in the figure (as far as the left - side arrow is enlarged compared to the right), with the effect that in response to the Strominpuls the Anchor moved to the right end position from the stable center position.

In addition, it has proved advantageous in the context of the realization of the exemplary embodiment described that a movement or holding in a middle position according to FIG Fig. 12 is also possible by energizing the coil unit with an alternating signal; With a suitable frequency setting, this leads to the fact that, by permanent Umpolen, the center position can be reliably reached and maintained.

The present invention is particularly suitable for forming a camshaft adjustment, so that the use for the purpose of the camshaft adjustment of an internal combustion engine is claimed as belonging to the present invention. However, the present invention is not limited thereto. Rather, the present invention is suitable for any setting purpose, which allows or uses a bistable electromagnetic locations.

Claims (14)

1. A bistable electromagnetic positioning device with
   an armature unit (10, 12, 10, 14, 16, 18, 20, 22) that can be moved along a longitudinal axis of movement between at least two actuated positions relative to a stationary coil unit (26) and in response to an energisation of the same,
   which has engagement means (40) at one or both ends for purposes of operating in conjunction with a downstream unit that is to be positioned, wherein
   the armature unit has permanent magnetic means (12, 14) on both sides of the coil unit in the direction of the longitudinal axis of movement, which are designed for purposes of operation in conjunction with a stationary core region (24) assigned to the coil unit such that, in response to the energisation of the coil unit with a DC voltage signal of a first polarity, the armature unit is moved into a first of the actuated positions, which is preferably at one end and stable when no power is applied,
   and in response to the energisation of the coil unit with a DC voltage signal of a second polarity, the armature unit is moved into a second of the actuated positions, axially opposed to the first actuated position, preferably at the other end and stable when no power is applied, wherein
   the armature unit is of an elongated design and has a shaft section (10) provided centrally, which extends through the coil unit and/or the core region, wherein the positioning device is accommodated in a housing (30) of a magnetically conducting material,
   characterised in that,
   in addition the shaft section (10) has separate, permanent magnetic flux-conducting sections (60) adjoining the respective permanent magnetic means on both sides, wherein
   the core region likewise has permanent magnetic flux-conducting disks (62) at both ends,
   such that the armature unit can be moved to a third of the actuated positions, at which mutually opposed forces of attraction of the permanent magnetic means do not cause any of the permanent magnetic means to adhere to the core region, in that in the third actuated position a closed permanent magnetic flux (66) over the surrounding housing is enabled by the respective flux-conducting section (60) and the associated flux-conducting disc (62) for each permanent magnetic means, wherein
   the third actuated position lies along the direction of the longitudinal axis of movement between the first actuated position at one end and the second actuated position at the other end.
2. The device in accordance with claim 1,
   characterised in that,
   the core region and the permanent magnetic means are designed such that in the first and/or the second actuated position, the permanent magnetic means adhere magnetically to the core region.
3. The device in accordance with claim 1 or 2,
   characterised in that,
   the coil unit and the core region operate in conjunction with the permanent magnetic means such that the energisation, preferably single pulse, causes a magnetic repulsion of a first permanent magnet of the permanent magnetic means, as well as a magnetic attraction of a second permanent magnet of the permanent magnetic means, located axially opposite the coil unit, for a positioning procedure from the first to the second actuated position.
4. The device in accordance with one of the claims 1 to 3,
   characterised in that,
   the third actuated position is stable when no power is applied and/or is located centrally between the first actuated position at one end and the second actuated position at the other end.
5. The device in accordance with one of the claims 1 to 4,
   characterised in that,
   the armature unit extends axially centrally or eccentrically through the coil unit (26), that is to say, the core region (24).
6. The device in accordance with one of the claims 1 to 5,
   characterised in that,
   the permanent magnetic means have permanent magnets (12, 14), preferably in the form of discs, provided axially at both ends of the coil unit and/or the core region.
7. The device in accordance with one of the claims 1 to 6,
   characterised in that,
   the engagement means are designed as a disc-shaped armature end face (16, 18), which moves a plunger unit (40) operating in conjunction with the armature end face.
8. The device in accordance with claim 7,
   characterised in that,
   the plunger unit (40) is releasably held on the armature end face by the permanent magnetic adhesive action of the permanent magnetic means.
9. The device in accordance with claim 6 or 7,
   characterised in that,
   the plunger unit has a plurality of sections in the axial direction, wherein
   a first section facing the armature end face is formed from a magnetic material, and an axially adjacent second section operating in conjunction with the unit is non-magnetic.
10. The device in accordance with claim 9,
    
    characterised in that,
    the first and second sections are permanently bonded with each other, in particular by sintering or friction welding.
11. The device in accordance with claim 9 or 10,
    characterised in that,
    the second section is hardened and/or wear-resistant at at least one engagement end for operation in conjunction with the unit.
12. The device in accordance with one of the claims 1 to 11,
    characterised in that,
    the armature unit operates at one or both ends in conjunction with spring means (50, 52, 54), wherein
    the spring means are preferably supported on an axial armature end face (16, 18) of the armature unit.
13. The device in accordance with one of the claims 1 to 12,
    characterised in that,
    the housing is implemented in terms of a bow-shaped housing element and/or one that is U- or L-shaped in longitudinal section, of which at least one leg (36) extends parallel to the longitudinal axis of movement, wherein
    the housing element has an opening (39) for purposes of passing a central and/or connecting section (10) through between permanent magnets of the armature unit.
14. The device in accordance with claim 13,
    characterised in that,
    the housing has a pair of housing elements, interleaved with one another and/or against one another, bow-shaped and provided with respective axially aligned apertures.

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