EP2878001B1 - Electromagnetic positioning device - Google Patents

Description

The present invention relates to an electromagnetic actuator according to the preamble of the main claim.

Such a device is well known for a variety of control tasks, such as in connection with internal combustion engines and is mass produced. The German utility model 20 2009 010 495 the Applicant shows such, presupposed as a generic educated electromagnetic actuator in which an elongated plunger as a ram unit is part of a multi-part armature unit, which in turn, radially symmetrically formed, can be driven by energizing a stationary coil unit relative to a stationary core unit for moving the plunger. The plunger unit, in turn, engages in an adjusting partner at the end, in the exemplary embodiment a groove effecting a camshaft adjustment of an internal combustion engine.

Such devices, which are presupposed and established as generic, combine high reliability and low wear with favorable electromagnetic and manufacturing properties, the latter making the known technology suitable in particular for mass production. However, it is necessary in such devices, at least partially or in sections, to enclose the stationary core area as far as the permanent magnet unit of the anchor unit, which is the case in concrete implementations of the technology DE 20 2009 010 495 was realized by bow-shaped housing elements. However, especially in space-critical installation spaces, such as on an internal combustion engine camshaft area, such flow-conducting housing parts limit the minimum installation dimensions that can be achieved, in fact giving a minimum distance of approximately a plurality adjacent to one another Actuators before. Accordingly, there is a need for a compact, in particular in the radial direction, to be realized housing structure.

A further disadvantage of the cited generic type technology which is in need of improvement is that in a de-energized stop state of the armature unit (typically in the retracted state of the tappet unit), adhesive forces which hold the armature unit to the core area are limited. Accordingly, there is no (or only a very limited) possibility to provide a compression spring or the like force accumulator between the armature unit and the core unit, with which then, to achieve high dynamic properties (corresponding approximately to a high start-up acceleration of the armature unit) in the energization case, the armature unit the stop or rest position can be driven out: The holding forces at rest determine so far a maximum, usable here spring force. Accordingly, it is desirable from this point of view to increase permanent magnetically caused holding forces of the armature unit on the stationary core region (core unit), in order to enable a more effective spring support of the armature movement.

Object of the present invention is therefore to improve a generic electromagnetic actuator both in terms of their dynamic characteristics, in particular their movement and acceleration behavior with application of energization, as well as to make the device in the radial direction more compact, with the purpose of a possible Minimum distance to each other adjacent ram units of a plurality of adjacent and parallel to each other provided adjusting devices to reduce.

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 accordance with the invention advantageously provided by the shell side of a shaft portion of the armature unit, magnetically non-conductive sleeve means a magnetic flux guide such that in the de-energized (stop) state of the armature unit, the permanent magnet flux provided in or on the armature unit permanent magnet means for closing a permanent magnetic flux circuit, both by the shaft portion (the anchor unit) flows, and, radially outward, by the radially enclosing core region, more preferably this permanent magnetic flux guide is configured in the de-energized state that the permanent magnet flux to the (magnetically non-conductive according to the invention) socket flows around.

Advantageous result in the context of the invention is a good permanent magnetic adhesion of the armature unit to the core unit in the de-energized state, since, in so far as distinguished from the generic type DE 20 2009 010 495 , an axially acting working air gap can be created between a portion of the armature unit and an end of the core unit without additional components having a small air gap. The advantage of this improved permanent-magnetic adhesive force is then the possibility of biasing the armature unit against the core area or another stationary section by means of suitable spring means, which can be configured as a spiral and / or compression spring, to improve the movement or dynamic properties of the device ,

If, in accordance with the invention, a displacement of the permanent magnetic flux from the core unit and into a (magnetically conductive) housing section, which interacts with the ram unit to form a flux circuit, is advantageous by energizing the coil unit, this pressure spring can, in addition to the (electro) magnetic repulsion, Accelerate anchor unit and thus improve the dynamic behavior of the anchor unit in the desired manner.

According to the invention, for this purpose, the ram unit, in particular at its directed to the permanent magnet means end, included in a magnetic flux guide and thus allows in particular that, geometrically advantageous and space-saving in terms of a radial installation space, lateral housing or Flußleitabschnitte, such as they were necessary in the generic state of the art, can be saved.

In a concrete advantageous embodiment of the invention, it is particularly advantageous in terms of further development to integrate the spring means designed as a spiral and / or compression spring into an end section of the armature unit (more precisely: the shaft section of the armature unit), so that additional space-saving action can be taken here; Typically, it is possible without disadvantages in the magnetic efficiency to use such, advantageously used spiral spring approximately in an end-side inner expansion of the shaft portion and support them at one end to a corresponding inside annular shoulder in the anchor unit, the other end at a core-side, stationary section.

It is particularly preferred within the scope of the invention to provide the elongated ram unit, realized at least in the direction of the permanent magnet means of a suitable soft magnetic and / or magnetically conductive material, releasably provided on the shaft portion of the armature unit, with the result that the armature unit in several parts (shaft portion , Ram unit) is realized. In this embodiment, it is particularly preferable to design a flat and / or radially widening end section of the shank section suitable for cooperation with the associated end of the ram unit, whereby in the practical realization this can be realized, for example, by a disk-shaped flux guide section, which end side the (further education in turn ring and / or disc-shaped) permanent magnet unit (as a permanent magnet means) ansitzt. In particular, such a configuration then makes it possible, by permanent magnet action, according to training only by the permanent magnet effect of the already existing anchor permanent magnet means, the plunger unit releasably adhere to the end portion of the shaft portion, so that maximum flexibility, combined with tolerance compensation options in installation and operating conditions can be realized. Additionally or alternatively, it is conceivable to design the ram unit itself (at least in sections) permanently magnetically, in order to realize such a magnetic adhesive effect.

The permanent magnet means attached to the armature unit, more preferably permanently attached, are made of a suitable permanent magnet material and axially magnetized, i. in a magnetization direction which runs parallel to the direction of movement of the armature unit and to a longitudinal axis through the shaft portion of the armature unit.

In order to incorporate the ram unit (or an end section of the ram unit) into a magnetic flux circuit when the coil unit is energized, in this operating state, the permanent magnet flux of the permanent magnet unit is displaced in such a way that it forms a closed (permanent magnet) section over a portion of the housing and a permanent magnet side end region of the ram unit. ) Flow circuit forms - is the housing, at least in the region of the plunger unit, advantageously and further configured such that it has a cup shape or bow shape and / or radially surrounds the (further advantageously radially widened in this area) shaft portion in the outer region. An air gap to the tappet unit may, for example, and preferably be done by the housing section for passing the (elongate) ram unit offers a suitable, adapted to an outer diameter of the ram unit breakthrough and so the inventive, displaced permanent magnet flux not only act as a flux circuit for the energization state of the coil unit can, but in addition and advantageously by the housing portion, in particular a front-side housing portion, a stop for an extended state of the anchor unit can be created; Also in this extended stop state of the anchor unit so that closing the permanent magnetic circuit according to the invention on the housing section, the portion of the plunger unit and possibly an additional, axially remote from the plunger unit (based on the permanent magnet means) Flußleitabschnitt the armature unit, so that even with again de-energized Coil unit in this extended stop state, a stable stop position can be achieved, as far as a bistable switching behavior of the device can be achieved.

In structurally particularly simple and favorable for automated manufacturability manner realized as a hollow cylindrical bushing bushing made of steel 1.4301 pressed into the core section, so that not only results in a mechanically stable and insoluble compound, but also a portion of the socket from the Core area protrudes or protrudes, with the possibility that the socket can then be enclosed not only on the inside by the anchor unit, but also on this protruding portion on the outside of the anchor unit. This in turn makes it possible in a structurally elegant manner to realize the inventive principle of guiding the permanent magnetic flux of the permanent magnet means around the bushing (more precisely, the bushing wall) around, in the currentless state of the coil unit.

As a result, in a surprisingly simple and elegant manner, the present invention makes it possible to further develop a generic electromagnetic actuator with a reduced diameter in the core region and improved dynamic or acceleration properties, so that in a particularly preferred field of application of the present invention, namely the controller of functionalities of a Internal combustion engine, here new and additionally advantageous applications are opened. However, the present invention is not limited to the field of application "engine technology", but rather the device according to the invention is suitable for any application in which a simple to produce, simultaneously powerful electromagnetic actuator technology is to be combined with advantageous flow control properties.

Fig. 1:

eine schematische Längsschnittansicht durch die elektromagnetische Stellvorrichtung gemäß einer ersten Ausführungsform der Erfindung in einem unbestromten Betriebszustand der Spuleneinheit;

Fig. 2:

eine Darstellung analog Fig. 1 zu einem Zeitpunkt, bei welchem eine Bestromung der Spuleneinheit aktiviert wird, sich die Ankereinheit jedoch noch im ausgangsseitigen Anschlagzustand befindet, und

Fig. 3:

eine Darstellung der Stellvorrichtung analog Fig. 1, Fig. 2 im Bestromungszustand der Spuleneinheit zeitlich nach dem Zustand der Fig. 2 mit in eine herausgeschobene bzw. ausgefahrene Position der Stößeleinheit bewegter Ankereinheit, angeschlagen an einer gegenüberliegenden Gehäuse-Anschlagsposition.

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 longitudinal sectional view through the electromagnetic actuator according to a first embodiment of the invention in a de-energized operating state of the coil unit;

Fig. 2:

a representation analog Fig. 1 at a time at which energization of the coil unit is activated, but the armature unit is still in the output side stop state, and

3:

a representation of the adjusting device analog Fig. 1, Fig. 2 in the energized state of the coil unit in time to the state of Fig. 2 with in an extended or extended position of the ram unit moving anchor unit, hinged to an opposite housing stop position.

The Fig. 1 to 3 show in the schematic longitudinal sectional view of the electromagnetic actuator according to the invention in a preferred embodiment of the invention, reference numerals apply to all representations.

In that regard, according to the generic technology of DE 20 2009 010 495 the radially symmetrical device consists of a stationary (ie mounted and even immovable) core unit 10, which forms a bottom end portion 12 and is enclosed on the shell side by a coil unit 14 held on a coil carrier (not shown).

An armature unit 18 is formed by means of a shank portion 20 immersed in the base portion 12 opposite to the bottom portion 12 by means of a flange portion 16, the shank portion having a radial extension 22 of an axially extending aperture in the direction of the bottom 12, into which extension a coil spring 22 is used, which, the armature unit biasing with its spring force, supported by the bottom element 12.

At the other end, the shaft portion 20 of the armature unit 18 has a flange-like widening portion 26, to which an annular permanent magnet 28, axially magnetized in a direction parallel to the longitudinal extension of the shaft portion 20, is attached, so that the flange-like widening portion 26, together with a further flange portion 30 of Anchor unit, axially acting on both sides of the permanent magnet ring as a flux guide.

A made of soft iron, elongated-cylindrical ram unit 31 sits magnetically adhering to the outside on the flange portion 26 and passes through an opening 33 in a housing 35 (can also directly in a guide tube seats).

On the shell side of the shaft portion 20, a hollow cylindrical bushing made of steel 1.4301 is pressed into the core unit 10 such that the bush is slidably seated on the inside of the shell portion of the shaft portion 20, in the outer region of the bush 32 an axial longitudinal portion by a press fit with the material the core unit 10 is formed and a further axial longitudinal section of the bush, axially adjacent, of the anchor unit, specifically, the flux guide portion, the permanent magnet unit 28 and the portion 26, is overlapped.

This then leads to that, illustrated by the arrow 40 in Fig. 1 in a de-energized state of the coil unit 14, a permanent magnet flux of the permanent magnet means 28 through the flux guide 30, the core unit 10, the elongated shaft portion 20 inside the sleeve and the flux guide 26 is closed as a flux circuit at the air gap and armature / stator interface ( 10 to 30) causes a strong permanent magnetic adhesion.

The device is dimensioned and set up in such a way that the permanent-magnetic adhesive force in this operating state is higher than a compressive force of the coil spring 24 acting on the armature unit.

The Fig. 2 shows the Bestromungszustand the coil unit, immediately after the activation of the energization. The arrow 42 shows the electromagnetically generated coil magnetic field (again, for simplicity, only one side of the radially symmetrical device provided with arrows), the arrows 42 displace the permanent magnetic flux 40 'out of the core unit 10, in a permanent magnetic flux circuit, which is now formed by the flux guide element 30, a radially enclosing, cup-shaped housing portion 50 of the housing 35, into a housing cover section 52 seated therein into a permanent magnet-side plunger end section 54 of the plunger unit 31, and via the flux guide section 26 as far as the axially magnetized permanent magnet ring 28.

In this operating state, the electromagnetic flux 42 then acts not only repulsively on the armature unit, but also the flux-displacement overcomes the permanent-magnetic adhesion of the armature unit to the core unit, and in addition acceleratingly, the compression spring 24 now acts on the armature unit Anchor unit to drive the ram unit out of the housing 35 (movement direction downwards in the plane of the drawing Fig. 1 to 3 ).

The final state of this drive movement shows the Fig. 3 , while still energized coil unit and partially relaxed coil spring 24: The housing portion 52 forms the inside of the stop for the armature unit 18, which abuts with the Flußleitabschnitt 26 to the suitably magnetically conductive, eg soft magnetic material. In addition, as the arrow 40 'illustrates, in this extended state of the ram unit, the armature unit - bistable - held by a permanent magnetic circuit, which by the armature assembly of flux guide 30, permanent magnet ring 28, flux guide 26, via the flux conducting 54 of the plunger unit 35 and the In the case of a typical application of a camshaft adjustment, an adjusting partner of the tappet element which acts in an opposing manner at the end 54 would then return the armature unit back to its starting position (FIG. Fig. 1 ) can spend.

The present invention is not limited to the embodiment shown; Rather, numerous other variants and configurations for respective applications are conceivable, in which according to the invention, the permanent magnetic flow diversion or displacement can be done to increase the dynamic behavior.

Claims (10)

1. An electromagnetic positioning device with an armature unit (18) that can be driven relative to a stationary core unit (10) in reaction to the application of current to a stationary coil unit (14), which armature unit has a permanent magnetic agent (28) as well as a plunger unit (31), designed so as to interact with a positioning partner, guided out of a magnetically flux-conducting housing (35),
   characterised in that,
   on the outer surface of a shaft section (20) of the armature unit (18) a magnetically non-conducting bushing agent (32) is provided such that in a zero applied current state of the coil unit (14) a permanent magnetic flux (40) of the permanent magnetic agent (28) flows through the core unit (10) and the shaft section (20) so as to hold the armature unit (18) on the core unit (10), and in a state of the core unit (14) in which current is applied the permanent magnetic flux (40', 40") is displaced out of the core unit (10) into a housing section (50, 52) of the housing and a permanent magnetic flux circuit is closed by a section (54) of the plunger unit facing towards the housing.
2. The device in accordance with claim 1,
   characterised by
   a spring agent (24), which for purposes of exerting a spring force driving the armature unit (18) engages with the armature unit (18).
3. The device in accordance with claim 2,
   characterised in that,
   the spring agent, designed as a spiral and/or compression spring (24), is provided on the end face of the shaft section (20), and/or is accommodated in an end section of the shaft section (20).
4. The device in accordance with one of the claims 1 to 3,
   characterised in that,
   the plunger unit (31) is provided in a detachable manner on a preferably planar flange- and/or end section (26) of the shaft section (20).
5. The device in accordance with one of the claims 1 to 4,
   characterised in that,
   the plunger unit is provided in a magnetically detained manner, in particular a permanent magnetically detained manner, on the shaft section (20).
6. The device in accordance with one of the claims 1 to 5,
   characterised in that,
   the permanent magnetic agent (28) is provided on an end region of the shaft section (20) facing towards the plunger, and/or is designed in the form of a ring and/or disk.
7. The device in accordance with one of the claims 1 to 6,
   characterised in that,
   the shaft section (20) is designed such that it is radially widened at the end facing towards the plunger, and/or provides a flux-conducting section, preferably radially oriented, for a permanent magnetic flux of the permanent magnetic agent (28).
8. The device in accordance with one of the claims 1 to 7,
   characterised in that,
   the housing section (50, 52) is designed in the form of a cup and/or yoke, and/or radially encloses at least some sections of the shaft section (20).
9. The device in accordance with one of the claims 1 to 8,
   characterised in that,
   the bushing agent (32) is connected in a non-detachable manner with the core unit (10), which is implemented from a soft magnetic material, in particular by means of a press fit process.
10. The device in accordance with one of the claims 1 to 9,
    characterised in that,
    no magnetic conducting element is provided on the outer surface of, and/or radially adjacent to, the coil unit (14).

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