EP2474009A1

EP2474009A1 - Bistable electromagnetic actuating device

Info

Publication number: EP2474009A1
Application number: EP10743039A
Authority: EP
Inventors: Thomas Golz; Thomas Schiepp
Original assignee: ETO Magnetic GmbH
Current assignee: ETO Magnetic GmbH
Priority date: 2009-09-01
Filing date: 2010-08-11
Publication date: 2012-07-11
Anticipated expiration: 2030-08-11
Also published as: WO2011026553A1; DE102009039562A1; EP2474009B1; DE102009039562B4

Abstract

The invention relates to a bistable electromagnetic actuating device with an armature unit (10, 12, 14, 16, 18, 20, 22), which is capable of being moved along a longitudinal axis of movement between at least two actuating positions relative to a stationary coil unit (26) and in response to said coil unit being energized and which has engagement means (40) at one or both ends for interacting with a downstream assembly to be actuated. According to the invention, the armature unit has permanent magnet means (12, 14) on both sides of the coil unit in the direction of the longitudinal axis of movement, said permanent magnet means being designed to interact with a stationary core region (24) associated with the coil unit in such a way that, in response to the energization of the coil unit with a DC voltage signal of a first polarity, the armature unit is brought into a first one of the actuating positions, which is preferably at the end and is stable in the de-energized state, and, in response to the energization of the coil unit with a DC voltage signal of a second polarity, the armature unit is brought into a second one of the actuating positions, which is axially opposite the first actuating position, and is preferably at the end and stable in the de-energized state.

Description

Bistable electromagnetic actuator

The present invention relates to a bistable electromagnetic actuator according to the preamble of the main claim. Such a device is well known in the art.

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 retraction anchor, have a single stable position (setting position) in which the anchor 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 coil energization) stably , An example of such a known device is shown in 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) control 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 a bistable 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 moving from the second setting position into the first setting position quickly, without external mechanical influence on the armature unit (by an actuating partner) and with minimization of switching times and energy expenditure to be made possible.

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.

In an advantageous manner according to the invention, the (stationary) coil unit in the axial (movement) direction is assigned on both sides to permanent magnet means at the armature, which act and are poled in such a way that, in response to a (impulse-shaped, in particular temporally limited to the movement process) DC signal, the armature movement takes place in the manner of a switching operation. 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 magnet adhering to the core region exceeds the permanent magnetic adhesive force; In addition, the permanent magnetic attraction by the (axially opposite) further permanent magnet is effective.

In a structurally particularly suitable manner, the armature unit is elongated to realize this basic functionality and has a central shaft portion, which extends in accordance with preferred embodiments of the invention through the coil unit or the stationary core area and at both ends a permanent magnet, each more preferably in disk form, realized and optionally 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 context, it is particularly favorable and preferred according to the invention for such an engagement-side ram unit not to be firmly connected to the Kerkereinheit to connect, but to effect a detachable connection. By providing the permanent magnet means, the present invention makes it possible for such a metallic ram unit to be magnetically adhered to an anchor end face 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 training and provided to form a plurality of such plunger, which can be guided not only axially or axially parallel to the direction of movement, but also skew or otherwise.

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 adhesive action between armature unit and ram unit 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 armature unit opposite engagement region of the plunger unit to realize a non-magnetic material, which further training in terms of its hardness, toughness or the like. for interaction with the intervention partner (eg the camshaft) can be optimized by suitable material treatment. In the context of further preferred embodiments, it is here, both sections (magnetically on the one hand for adhering to or on the armature end face, non-magnetic grip for an aggregate on the other hand) realize as a permanently connected unit, where they od particular connection methods such as sintering, friction welding .dgl. 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. In this case, it is preferable to support such a spring (eg compression spring) on the end face of the anchor at one end or at both ends, such a support both inwards (ie in the movement space between the core region and the permanent magnet), as well as outwardly (approximately surrounding a ram unit). can be done.

A further preferred embodiment of the invention 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 extends parallel to the longitudinal axis of movement preferably between the setting 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 circumferentially around 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 against each other, creates an easy to install, mechanically stable and magnetically effective housing construction.

In the context of the invention, it is also possible to develop the erfindunsgemäße bistable electromagnetic actuator as a tristable electromagnetic Stellvor- direction, which is to fall within the scope of the invention, the term "unstable" as a special education under the general term "bistable". Specifically, it is encompassed by the invention according to a preferred development, not (only) two stable states by means of the inventive device. but to enable 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 stably occupied by the device, more preferably characterized in that also here (ie without energizing the coil unit) the armature in this position remains.

In a preferred realization, this tristillability-inducing position is achieved by the permantent magnet means of the armature unit, which are advantageously provided at both ends, cooperating with a (central) stationary core area in such a way that none of the permanent magnet units adhere to the core unit due to opposing attractive forces one (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 parking 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 weiterbildunsgemäß advantageous tristability then allows completely new applications 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, wherein advantageously and further education, at least two of these, more preferably all three, each without current are stable. As a result, it thus enables the invention to realize a structurally simple and thus suitable for large-scale production a bistable actuating device which combines short positioning times with high energy efficiency during operation.

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:

1 shows a schematic side view of the bistable electromagnetic actuating devices according to a first embodiment of the invention, wherein the armature is in a first parking position on the left;

FIG. 2: a representation analogous to FIG. 1 with the armature extended into the second setting position (right); FIG.

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

4: a representation analogous to FIG. 3 at the beginning of the energization of the coil unit and before a movement into the second setting position; Fig. 5 is a perspective view of a bow-shaped housing unit with a pair of legs;

6 shows an arrangement of two nested housing bars (FIG. 5) with an anchor unit guided therein and a mounted coil unit; various views of the anchor end face (s) of the device of Figure 6 to illustrate the interaction with one or more plunger units. a representation analogous to Figure 2 with a pair of both sides axially from the outside on the anchor end faces cross springs. FIG. 11 shows a variant of a spring insert between core region and permanent magnet armature disk; FIG.

Fig. 12: a longitudinal section through a bistable electromagnetic

Adjusting device 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 control position, suitable magnetic flux arrows are drawn to the extent the normally current stable state (together with permanent magnetic Force arrows), and

Fig. 13: a view analogous to FIG. 12, but with an additional energization of the coil unit, through which then the (center) equilibrium of FIG. 12 dissolved and the anchor unit can be brought into an end position.

Figures 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 sides ansitzenden permanent magnet discs 12 and 14, the permanent magnet discs each axially outwardly final armature discs 16th , 18 and the permanent Magnetic discs 12, 14 axially inward limiting 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. 3, 4) is arranged surrounding the shaft region 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; Thus, in the parking position of Figure 1, the right-most permanent magnet 14 adheres to the core unit 24, while the permanent magnet 12 is axially extended. FIG. 2 illustrates the reverse, axially displaced state of the armature (second setting position).

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

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 to the anchor unit, which then drives the anchor unit (in the figure on the right) into the second setting position of FIG. 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 Figures 3, 4), with respect to the opposite permanent magnet, is oppositely poled in the axial direction. Figures 5, 6 illustrate how the housing 30 can be made in an elegant manner of bow-shaped elements space and effort saving; More specifically, a U-shaped stirrup member 34 shown in Figure 5 is formed of a pair of legs 36 (these extend, as shown in Figure 6, parallel to the axial direction of travel) and a central portion 38 which is both legs 36 connects. The central portion 38 has a central opening 39 through which the shaft portion 10 of the armature can move.

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

It is made clear with reference to FIGS. 7 to 9 that an outer face of the armature disks 17 or 18 offers different possibilities for driving ram elements (ram units) 40 seated thereon. According to preferred embodiments, at least one plunger element 40 (alternatively also two or more, see the figures 8, 9, wherein the figure 9 also carries in the opposite direction a plunger element) by means of magnetic adhesive force, characterized in that the plunger element 40 of magnetic Mate - Rial of the permanent magnet 12 and 14 is held on the respective flat end face (this can be parallel to the axis, centric, alternatively also skewed, depending on the 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) with a permanent magnet disc having an anchor unit can cooperate. In addition, according to the development of the invention, it is provided that the tappet unit shown in elongated cylindrically 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 can then be assembled in a suitable manner, for example via sintering, friction welding or the like, permanently and inseparably. Figures 10 and 11 illustrate ways in which, based on the configuration of Figures 1 and 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 on other, otherwise known manner can be used.

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

The longitudinal sectional view of FIG. 12 illustrates the slightly different structural design of the armature unit, in which case the central shaft region 10 has additionally been supplemented by permanent-magnetically flux-conducting sections 60 which likewise allow a flux-guiding action via the surrounding housing 30 as disks 62. In that regard, the closed thin arrowheads 66 illustrate a permanent magnetic flux, symmetrically in the manner shown in FIG. 12, which holds the anchor unit in a central position between both end positions, as in connection with FIG described first embodiment, allows. More specifically, two permanent magnetic force arrows shown in FIG. 12 as thick arrows 68 illustrate how a stable center condition is achieved by permanent magnetic attraction of the discs 12, 14 and without energizing the coil since, with approximately the same permanent magnetic attraction and symmetrical geometry, the two are aligned Forces 68 neutralize themselves. This intermediate state can be achieved by pulsing the coil unit for a short time in order to bring the armature unit into this state, in which case the energizing is terminated before a stop takes place at the opposite end.

Based on the geometry of FIG. 12, the now possible energization, as produced by a pulse and according to the arrow 70, produces a repulsive effect in the left-hand area in the figure (insofar as the left-hand arrow is enlarged in relation to the right), with the effect that that, in response to the current pulse, the armature moves to the right end position from the stable center position.

In addition, it has proved to be advantageous in the context of realizing the exemplary embodiment described that a movement or holding in a center position according to 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

claims

Bistable electromagnetic actuator with

an armature unit (10, 12, 14, 16, 18, 20, 22) movable relative to a stationary coil unit (26) and in response to an energization thereof along a longitudinal movement axis between at least two actuating positions,

the one or both ends engagement means (40) for interacting with a downstream, to be set unit, characterized in that the armature unit in the direction of the movement longitudinal axis on both sides of the coil unit permanent magnet means (12, 14) which are assigned to cooperate with one of the coil unit stationary core region (24) are formed so that, in response to the energization of the coil unit with a DC voltage signal of a first polarity, the armature unit is placed in a first, preferably end-side and currentless stable of the setting positions

and in response to the energization of the coil unit with a DC voltage signal of a second polarity, the armature unit is moved to one of the first control position axially opposite second, preferably end-side and normally-free stable of the control positions.

Apparatus according to claim 1, characterized in that the core region and the permanent magnet means are formed so that in the first and / or the second setting position, the permanent magnet means adhere magnetically to the core region. Apparatus according to claim 1 or 2, characterized in that the coil unit and the core area so cooperate with the permanent magnet means, that the preferably once-pulse energization of a magnetic repulsion of a first permanent magnet of the permanent magnet means and a magnetic attraction of a axially opposite to the coil unit second permanent magnet causes the permanent magnet means for a setting operation from the first to the second setting position.

Device according to one of claims 1 to 3, characterized in that the armature unit and the permanent magnet means are formed so that the armature unit can be moved to a third, preferably currentless stable of the parking positions, wherein the third parking position along the direction of the longitudinal axis of movement between the first end-side parking position and the second end-side parking position, in particular centrally between them.

Apparatus according to claim 4, characterized in that the coil unit is formed so that it spends in cooperation with the permanent magnet means and in response to a temporary and / or alternating current supply, the armature unit in the third setting position.

Device according to one of claims 1 to 5, characterized in that the anchor unit is formed elongated and has a preferably centrally provided shaft portion (10) which extends through the coil unit and / or the core region.

7. Apparatus according to claim 6, characterized in that the armature unit extends axially centrally or eccentrically through the coil unit (26) or the core region (24).

8. Device according to one of claims 1 to 7, characterized in that the permanent magnet means provided axially at both ends of the coil unit and / or the core region, preferably disc-shaped permanent magnets (12, 14).

9. Device according to one of claims 1 to 8, characterized in that the engagement means as a disc-shaped anchor end face (16, 18) are formed which moves a cooperating with the armature end face ram unit (40).

10. The device according to claim 9, characterized in that the plunger unit (40) is releasably and held by permanent magnetic adhesive effect of the permanent magnet means on the anchor end face. 11. The device according to claim 8 or 9, characterized in that the plunger unit has a plurality of sections in the axial direction, wherein a first, directed to the armature end face portion of magnetic material is formed and an axially adjacent second, cooperating with the aggregate section non-magnetic is.

Apparatus according to claim 119, characterized in that the first and the second portion, in particular by sintering or friction welding, are permanently connected to each other.

Apparatus according to claim 11 or 12, characterized in that the second portion is hardened at least at one engagement end for the interaction with the unit and / or designed wear-resistant.

Device according to one of claims 1 to 13, characterized in that the anchor unit on or at both ends with spring means (50, 52, 54) cooperates, wherein the spring means are preferably supported by an axial armature end face (16, 18) of the anchor unit.

15. Device according to one of claims 1 to 14, characterized in that the adjusting device is accommodated in a housing made of a magnetically conductive material, wherein the housing has a wall portion (36) which is parallel to the movement longitudinal axis, in particular between the adjusting positions of the permanent magnet means , extends.

16. The apparatus according to claim 15, characterized in that the housing is realized by means of a bow-shaped and / or longitudinally U- or L-shaped housing member whose at least one leg (36) extends parallel to the longitudinal axis of movement, wherein the housing element has an opening (39 ) for passing a middle and / or connecting portion (10) between permanent magnets of the armature unit.

17. The apparatus of claim 15 or 16, characterized in that the housing has a pair of nested and / or against each other nested, bow-shaped and provided with respective axially aligned apertures housing elements.