EP2593945B1 - Electomagnetic actuating device - Google Patents

Description

The present invention relates to an electromagnetic actuator according to the preamble of the main claim. Such devices are for example from the German utility model 201 14 466 known and are suitable for numerous adjusting devices. A preferred application of such a device is the camshaft adjustment; In this case, the sliding or tappet unit connected to the movable armature unit acts on a camshaft of an internal combustion engine and thus effects a desired adjustment functionality.

Especially in the context of an internal combustion engine or similar field of application, reliable operation is particularly important, with the particular ambient conditions (high temperature, vibration, possibly a frost-cooled motor) leading to occasional malfunctions, which must be reliably detected. Correspondingly, so-called reset detection technologies are known for electromagnetic positioning devices of the prior art, wherein, for example, an induction signal detected and evaluated in a de-energized state of the coil unit is evaluated at the connection terminals of the coil unit in accordance with the camshaft position. Such a device shows, for example, the DE 10 2006 035 225 A1 the applicant.

However, this technology, with other similar, at this point not deepened approaches from the prior art, however, has the disadvantage that a malfunction from a respective terminal signal is difficult to determine and, accordingly, a downstream evaluation electronics consuming and error prone itself. In addition, there is the disadvantage that this known induction technology can detect only a movement of the plunger or the anchor unit in principle, but not a respective plunger position; In particular, it is not possible with means for evaluating an induction coil voltage to reliably detect a (stationary) end position of the ram engaging approximately in the camshaft.

Accordingly, the not yet public utility model application at the time of the present application 20 2009 006 940 the applicant, Alternatively to the measurement of a coil voltage (induced by the permanent magnet unit) for detecting the position of the armature stationary sensor means (as a magnetic field detection means) in a housing or a carrier unit of the adjusting device, which cooperate magnetically detecting with the permanent magnet means and in response to a movement or position the permanent magnet means (corresponding approximately to a movement or position of the armature unit) output an associated magnetic field detection signal for further processing. This signal is initially independent of a Bestromungs- or non-Bestromungszustand the coil unit and in particular also independent of a movement or standstill situation of the armature, such as Fig. 9 to the referenced internal prior art of this utility model application: in a (not shown) housing unit, a stationary coil unit 10 is provided, which is formed around a stationary core 12 around. Relative to these stationary units in the axial direction (ie longitudinal direction in the Fig. 9 ) is movably mounted an anchor unit 14 with ansaftender ram unit 16, which is formed with its engagement-side end 18 in otherwise known manner for cooperation with a groove of a camshaft adjustment.

The armature unit 14 has a (disk-shaped) permanent magnet unit 20, which is axially magnetized in the manner shown, and thus faces the core unit 12, that in response to an energization of the coil unit 10, the armature unit 14 together with ansaftender ram unit 16 (this is either fixed or through Holding force of the permanent magnet unit 20 releasably held on this) in the axial direction (ie in the Fig. 9 downwards) is moved.

To realize the position detection is associated with this internal state of the art, the permanent magnet unit 20, a stationary sensor unit 22 (suitable in the case not shown in the figures) assigned, which detects the permanent magnetic field and, realized as a Hall sensor, this magnetic field and its change Detect movement of the anchor unit 14 and perform a subsequent electronic evaluation.

Thus, this solution is able to overcome the inherent disadvantages of the prior art discussed above.

However, such a solution, which is based on the Fig. 9 was shown generically and schematically and then in an individual case, of course, concrete design, in need of improvement. Thus, although the idealized state of the schema representations of the Fig. 10a (Attracted state of the armature unit 14, shown only the permanent magnet disc (20) and the Fig. 10b (Removed state of the armature unit) of the coil unit 10 shown schematically including core 12 that effectively the sensor unit 22 by each different field profile 21 of the permanent magnet unit 20 relative to the stationary sensor unit 22 can make a good positional distinction (the schematic signal diagram according to FIG Fig. 10b in this respect, the course of movement of the drop over the level of Fig. 10a illustrated).

Taking into account a coil field which is always present in the energization case of the coil unit 10 (see the field lines 11 for this), however, it appears that these can cause a possible malfunction of the sensor unit 22 in the superposition. Thus, in particular the magnetic field lines of the coil field 11 superimpose a possible detection state in the dropped state ( Fig. 11b) the anchor unit, so that then this anchor position would not be detected correctly in the Bestromungsfall by the sensor unit 22 then.

From the DE 10 2008 019 398 A1 an electromagnetic actuator is known, with an in response to an energization of a stationary, axially aligned coil unit along or parallel to the axial direction driven armature unit, which is designed to cooperate with a extending in the axial direction slide and / or tappet unit, wherein permanent magnet means are provided on and / or in the armature unit and / or the slide or tappet unit and the armature unit and the armature unit are accommodated at least partially in a housing or support unit, wherein the support unit for stationary contact magnetic magnetic interaction with the permanent magnet means Assigned detection means and are designed so that in an energization and a non-Bestromungszustand the coil unit by evaluating a magnetic field detection signal of the magnetic field detection means an axial position of the armature unit and / or the slider or pusher unit can be determined electronically and the coil unit magnetic flux guide are assigned so that this one generated by the coil unit derive magnetic coil field of the magnetic field detection means and / or mitigate against these.

For further prior art, reference is made to the DE 199 39 428 C1 , the US 4,690,371 as well as the FR 2 886 485 ,

It is therefore an object of the present invention to improve a generic device, which additionally has stationary magnetic field detection means for interacting with permanent magnet means moved by armature movement for position and movement detection, in its detection properties, in particular to overcome any damaging influence of a magnetic coil field.

The object is achieved by the 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 device described, or more precisely the coil unit, is additionally associated with magnetic flux guides which are designed such that they adequately derive, shield and / or shield the magnetic coil field generated by the coil unit in the energized state from the magnetic field detection means Mitigate the decryption without at the same time significantly impairing or adversely affecting a detection of the permanent magnetic field of the permanent magnet means by the magnetic field detection means.

This is realized in a particularly advantageous manner in that the flux-conducting means in the form of a magnetically conductive material, e.g. Soft iron, realized flux guide elements are formed and are provided adjacent to the coil unit and / or axially parallel to this running, that in these flux-conducting elements, the coil magnetic field is bundled, thus shielding or weakening the (coil) magnetic field takes place on the sensor unit. This then leads according to the invention to the intended improvement of the movement or position measurement behavior by these sensor means (magnetic field detection means).

It is particularly preferred in the context of preferred embodiments, such a flux guide (either alone, or provided as a group and more preferably approximately with a common, for example, based on the coil unit front side, plate connected) elongate form, more preferably plate or profile-like shape and to arrange this / s with respect to the magnetic field sensor so that the sensor is suitably outside, approximately at the front, by a Flußleit-, bundle or shielding generated by the Flußleitmittel, so that even interact with the anchor-side permanent magnet means can not interfere.

Thus, it is provided, for example in the context of preferred embodiments, in the manner of a coil device or a plurality of adjacent coil devices edge-side or corner-enclosing a plurality of elongated flux guide elements axially parallel to the or the coil device (s) to be arranged, more preferably these flux-conducting along the axial coil length and then the sensor unit frontally facing this arrangement (or a single flux guide in the axial extension). At the sensor unit opposite the front end of the flux-guiding elements can then be provided in a suitable manner (again flux-conductively connected) flat guide element for all flux-guiding elements.

Alternatively, and within the scope of further preferred embodiments of the invention, it is advantageous to each a single coil unit or a plurality of coil units individually or together on the shell side to assign a shell of a magnetically conductive material, such as soft iron, which realizes the magnetic flux-conducting means; This shell can then be bent approximately cylindrically or cylinder-section-shaped, in accordance with further development, for example in the case of a coil pair, an axially extending, elongated shielding plate as flux guide element.

In the context of preferred embodiments of the invention, the slide or ram unit is releasably connected to the armature unit, in such a way that permanent magnet force of the permanent magnet means (releasably) holds the plunger unit to the armature unit. This gives the permanent magnet unit according to the invention a multiple synergistic effect: on the one hand, it provides by its repulsive force when energizing the coil for the armature movement in the context of the electromagnetic control function of the adjusting device. Moreover, as discussed, it offers the possibility of reliably detecting an armature movement and position at any time by means of the stationary magnetic field detection means (realized, for example, as a stationary sensor unit), and further additionally and advantageously, the permanent magnet unit provides the reliable, yet detachable one Connection between slide or ram unit and anchor unit forth (in that the anchor unit itself suitable permanent magnet means, such as a correspondingly magnetized disc has, and then the ram unit of magnetically conductive material, eg soft iron exists).

In the context of the present invention, this arrangement is magnetically shielded from potentially interfering with the sensor detection influences the coil magnetic field.

While it is within the scope of preferred embodiments of the invention to use a Hall sensor or the like magnetic field detector for the magnetic field detection means, the present invention is not limited thereto; rather, there are numerous ways and possibilities to realize a magnetic field sensor for the magnetic field detection means and suitably provide the armature unit adjacent to the housing.

Moreover, while the present invention can in principle already be realized favorably for a simple configuration from a single coil with this associated armature unit and corresponding to a sensor, the present invention Invention is not limited to such a configuration, but it is within the scope of preferred embodiments of the invention to provide a plurality of coil units, as well as a plurality of axially parallel or skew each other extending anchor units provide, which in turn are assigned to coil units, in which case either here individual flux guide elements can be provided for a common sensor, or multiple flux guide elements for a common sensor, or multiple flux guide elements can screen a plurality of sensors or suitably influence a coil field for them.

As a result, the present invention makes it possible in a surprisingly simple and effective manner to improve the technology already known from the internal state of the art with regard to its detection behavior, in particular its insensitivity to possible magnetic field influences of the energized coil, and thus also the present invention In view of a magnetic flux to make demanding or problematic operating conditions accessible.

Fig. 1a, 1b

ein Schemadiagramm zum Verdeutlichen der Wirkungsweise eines Paares von erfindungsgemäßen Flussleitelementen als magnetische Flussleitmittel betreffend eine wirksame Abschirmung eines magnetischen Spulenfeldes im Hinblick auf eine stationäre Magnetfeld-Detektoreinheit;

Fig. 2, 3

eine Schemaansicht der elektromagnetischen Stellvorrichtung, reduziert auf ein Spulenpaar, ein Permanentmagnet-Scheibenpaar als Anker, eine Flussleitblech sowie einen Magnetfeldsensor zum Verdeutlichen einer möglichen ersten Realisierungsform der Erfindung;

Fig. 4

eine Darstellung analog Fig. 2, 3 eines zweiten Ausführungsbeispiels der Erfindung;

Fig. 5

eine Darstellung analog Fig. 2, 3 eines dritten Ausführungsbeispiels der Erfindung;

Fig. 6

eine Darstellung analog Fig. 2, 3 eines vierten Ausführungsbeispiels der Erfindung;

Fig. 7

eine Darstellung analog Fig. 2, 3 eines fünften Ausführungsbeispiels der Erfindung;

Fig. 8

eine Darstellung analog Fig. 2, 3 eines sechsten Ausführungsbeispiels der Erfindung;

Fig. 9

eine Darstellung des Aufbaus einer elektromagnetischen Nockenwellen-Verstellvorrichtung als Schemaansicht mit einer Ankereinheit, einer dieser zugeordneten Stößeleinheit sowie einer mit Permanentmitteln der Ankereinheit zusammenwirkenden Sensoreinheit, gemäß internem Stand der Technik;

Fig. 10a, 10b

eine Verdeutlichung der idealisierten Sensorfunktionalität der Vorrichtung gemäß Fig. 9 unter Vernachlässigung eines Spulenmagnetfeldes und

Fig. 11a, 11b

eine Darstellung analog Fig. 10a, 10b unter zusätzlicher, die Sensorfunktionalität beeinflussender Berücksichtigung eines Spulenmagnetfeldes in bestromtem Zustand der Spule.

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

Fig. 1a, 1b

a schematic diagram illustrating the operation of a pair of flux guide elements according to the invention as magnetic flux guide means for effective shielding of a magnetic coil field with respect to a stationary magnetic field detector unit;

Fig. 2, 3rd

a schematic view of the electromagnetic actuator, reduced to a pair of coils, a pair of permanent magnet disks as anchors, a Flußleitblech and a magnetic field sensor to illustrate a possible first embodiment of the invention;

Fig. 4

a representation analog Fig. 2, 3rd a second embodiment of the invention;

Fig. 5

a representation analog Fig. 2, 3rd a third embodiment of the invention;

Fig. 6

a representation analog Fig. 2, 3rd a fourth embodiment of the invention;

Fig. 7

a representation analog Fig. 2, 3rd a fifth embodiment of the invention;

Fig. 8

a representation analog Fig. 2, 3rd a sixth embodiment of the invention;

Fig. 9

a representation of the construction of an electromagnetic camshaft adjusting device as a schematic view with an anchor unit, a tappet unit associated therewith and cooperating with a permanent means of the armature unit sensor unit, according to the internal prior art;

Fig. 10a, 10b

an illustration of the idealized sensor functionality of the device according to Fig. 9 neglecting a coil magnetic field and

Fig. 11a, 11b

a representation analog Fig. 10a, 10b under additional, the sensor functionality influencing consideration of a coil magnetic field in energized state of the coil.

Analogous to the representation of the Fig. 11a, 11b to the internal state of the art illustrates the juxtaposition of Fig. 1a, 1b (again for the tightened state of the anchor unit ( Fig. 1 a) , with anchor unit 14 - as a permanent magnet unit 20 - in the image display at the top of the coil 10 and in the fallen state of the Fig. 1b , with the armature unit (again shown only permanent magnet unit 20) in the plane of the figure below) that elongated flux guide elements 30, 32 provided additionally and adjacent to the coil unit 10, which axis parallel to the longitudinal axis by the coil unit 10 (which also describes the axis of movement of the armature) extend, the coil magnetic field generated by energizing the coil 11 bundle in these flux guides. In the practical geometric realization of Fig. 1a, 1b this has the effect that the coil magnetic field in the axial direction extends less long, thus no longer reaches the sensor 22 (or its sensitivity range). This then leads to that in the fallen state ( Fig. 1b in comparison to Fig. 11b) the position difference of the armature is detected only on the basis of the changed permanent magnetic field 21 and in particular the coil magnetic field 11 no longer exerts any influence on the sensor detection.

In the concrete realization, such as in the first embodiment of Fig. 2, 3rd with an axis-parallel coil pair 10a, 10b and corresponding associated armature pair (again reduced to the representation of the permanent magnet 20), both units energized separately - and thus are operable, it turns out that an effective flow control by a U-shaped in the exemplary embodiment, elongated flux guide 34 can be achieved which extends along the direction of extension of the coils 10a and 10b and even into an initial range of movement of the armature; the magnetic field sensor 22, a Hall sensor in the illustrated embodiment, is seated here on the shielding flux guide plate 34 made of soft iron, can thus interact unaffected with the permanent magnetic fields of the (again axially magnetized) units 14a, 14b, but remains largely uninfluenced by the coil magnetic fields in FIG energized state of the coils 10a and 10b.

The same applies to a second embodiment according to Fig. 4 as a modification of the first embodiment. Here, too, the sensor unit 22 sits at the end side and at the end side of the strip-like-planar and in turn longitudinally formed flux-conducting element 35; In addition, a shielding plate 36 is provided opposite the end face for further influencing the flux of the coil magnetic field of the coil pair 10a, 10b.

Again alternatively, according to the third embodiment of the Fig. 5 Here, the single flux guide element 34 is replaced by a group of four cross-sectionally square flux guide elements 38, which are connected at one end by means of the shielding plate 36, a cuboid, the pair of coil units 10 a, 10 b receiving space span, thus providing an effective magnetic flux influencing while turn the sensor unit 22 outside this clamped interior for cooperation with the anchor units (or the permanent magnet disks 20 provided there) is held.

The fourth embodiment of Fig. 6 shows a conceptual connection of the embodiments two ( Fig. 4 ) and three ( Fig. 5 ): Here, the flux guide elements are realized from a pair of corner-side rods 38 having a square cross-section and a between the pair of coils 10 a, 10 b provided baffle 35 (analogous to Fig. 4 ).

The fifth embodiment according to Fig. 7 provides that both coils 10a, 10b are largely surrounded on the shell side by cylinder-section-like shell elements 40, 42, which in turn are brought together at the end, the sensor unit 22 opposite, flow-conducting to the plate 36. The shells 40, 42 made of soft iron provide a predetermined flow and reach a principle according to Fig. 1a, 1b analogous effect.

The same applies to the sixth embodiment according to Fig. 8 , which in turn merges the shell-like shells 40, 42 with an additional shielding plate 35 according to the second embodiment of the Fig. 4 ,

All of these embodiments have in common that with a comparatively low production cost, without adverse magnetic influences, a potentially affecting the sensor detection result influencing influence of the coil magnetic field in the energization state of the coil can be suppressed or limited.

Claims (10)

1. An electromagnetic positioning device, in particular a cam shaft positioning device, with
   an armature unit (14), which in reaction to an energisation of a stationary, axially aligned coil unit (10) can be driven along the axis or parallel to the axial direction,
   which for purposes of interacting with a slider and/or striker unit (16) extending in the axial direction, is designed in particular as a striker unit effecting a displacement of a cam shaft of an internal combustion engine, wherein
   permanent magnet means (20) are provided on and/or in the armature unit in the form of a permanent magnet unit (14), which is designed such that by energisation of the coil unit it drives the armature unit by means of a magnetic repulsion effect,
   and the coil unit and the armature unit are at least partly accommodated in a housing or supporting unit,
   stationary magnetic field detection means (22) designed for non-contacting magnetic interaction with the permanent magnetic means are assigned to the supporting unit, and are designed such that in both an energised and a de-energised state of the coil unit an axial position of the armature unit and/or the slider or striker unit can be determined electronically by the evaluation of a magnetic field detection signal of the magnetic field detection means,
   magnetic flux-conducting means (30, 32; 34; 35; 36; 38; 40, 42) are assigned to the coil unit such that these deviate a magnetic coil field generated by the coil unit and/or weaken it relative to the former, and wherein
   the magnetic field detection means having a magnetic field sensor are at least partly enclosed by a purge moulding or over-moulding, in particular a polymer moulding, formed in the housing or supporting unit.
2. The device in accordance with Claim 1, characterised in that, the magnetic flux-conducting means are designed adjacent to the coil unit and extending parallel to the axis of the latter, at least in some sections.
3. The device in accordance with Claim 1 or 2, characterised in that, the magnetic flux-conducting means are designed as an elongated flux-conducting element (30, 32; 34), preferably shaped in the form of a plate or profile, to which are assigned on the end face the magnetic field detection means having the magnetic field sensor.
4. The device in accordance with one of the Claims 1 to 3, characterised by a multiplicity of elongated flux-conducting elements (30, 32; 38) running parallel to one another as flux-conducting means, which span an interior in which the at least one coil unit is provided, wherein the magnetic field detection means having the magnetic field sensor are arranged outside of the spanned interior.
5. The device in accordance with Claim 3 or 4, characterised in that, the at least one elongated flux-conducting element is connected on an end face opposed to the magnetic field sensor with a flux-conducting supporting and/or screening plate (36), which preferably extends in a plane running at right angles to the axis.
6. The device in accordance with one of the Claims 1 to 5, characterised in that, the magnetic flux-conducting means are implemented in a magnetically conducting material in the form of at least one shell (40, 42), the surface of which encloses the coil in at least some regions.
7. The device in accordance with one of the Claims 1 to 6, characterised in that, the slider or striker unit (16) are releasably held on the armature unit by means of a permanent magnetic holding force of the permanent magnetic means (14).
8. The device in accordance with one of the Claims 1 to 7, characterised in that, in the housing or supporting unit a multiplicity of armature units and/or slider or striker units (16) are provided that can preferably be driven independently of one another.
9. The device in accordance with Claim 8, characterised in that, in the housing or supporting unit a common or corresponding multiplicity of flux-conducting elements are assigned to the multiplicity of armature units, wherein the flux-conducting means for each coil unit have at least one elongated flux-conducting element running parallel to the axis.
10. The device in accordance with Claim 8 or 9, characterised in that, for at least two of the multiplicity of armature units a common magnetic field sensor is provided as a magnetic field detection means.

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