EP1729308A1 - Electromagnetic actuator - Google Patents

Abstract

The actuator has an armature (54) which is mounted in a sliding manner in a preferably hollow-cylindrical armature guide tube. The armature guide tube has multiple protrusions (56) which are arranged around a circumference of the guide tube and are formed in one piece from the material of the guide tube. The armature guide tube forms a closed bottom face (58) which is integrally formed in one piece.

Description

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

Such a device is known, for example, from the German patent application 102 35 644 of the Applicant, with reference being made to the illustration of the background of the invention by way of example to the Fig. 1 of this publication.

A generic electromagnetic actuator typically has a rotationally symmetric magnet frame held in a housing, which forms a guide tube for an anchor element. The guide tube is surrounded by a coil arrangement.

In response to an activation of the coil arrangement with an electrical signal, a force acts on the armature, whereby it in the axial direction in the armature guide tube (reference numerals 14, 16, 18 in Fig. 1 of DE 102 35 644 ) is moved.

In the realization of such devices, which are available in numerous variants and are used for a variety of applications, it depends on the between the armature circumferential surface and the (typically hollow cylindrical) inner surface of the guide tube: Sufficient clearance provides good movement and sliding properties of the armature in the armature guide tube, at the same time the smallest possible air gap is required for favorable electromagnetic properties, in particular, as to minimize transverse forces it is particularly important for a centricity of the armature relative to the guide tube. As a result, traditionally considerable production engineering effort is required in order to adapt both components to one another favorably in the manner described.

If, in addition, as with the exemplary in Fig. 1 of the DE 102 35 644 When the device shown is the case, the armature guide tube is closed at one end, each movement of the armature to a fluid movement, so that in the design of the guide tube-armature pair also depends on the hydrodynamic properties in the movement; in the cited prior art this is solved by a hole in the anchor. Depending on the purpose, however, this can also be disadvantageous.

An alternative, known embodiment of a guide tube-armature combination shows the DE 102 18 445 , Again, the armature of a magnet assembly is slidably mounted in a guide tube to form a sliding bearing and to allow fluid flow between the armature and armature guide tube, however, the armature has shell side provided on sliding elements. While by such a procedure, the described hydrodynamic properties can be controlled and the centering of the armature is improved in the guide tube, the realization of such a known device is nevertheless manufacturing technically complex and, for example from the point of mass production, problematic: in a complex manner is namely here to provide the armature with radially encircling, partly interrupted projections, in which case, in turn, an associated armature guide tube with respect to its inside diameter is adapted to adapt to the determined by such projections effective outer diameter. The DE 102 18 445 also points out the problem of a resulting, relatively large (and thus the electromagnetic efficiency affecting) air gap.

Object of the present invention is therefore to improve a generic electromagnetic actuator with respect to a guide of the armature in the armature guide tube, in particular to optimize the manufacturability of such a device and thus the series suitability and also the device for use with a closed-end armature guide tube in order to make suitable by armature movement resulting fluid flow.

The object is achieved by the device having the features of the main claim and the use according to the independent claim 10; advantageous developments of the invention are described in the subclaims.

Thus, it is particularly preferred to design the armature guide tube closed at one end; Not only can be created in this way a suitable for hydraulic or pneumatic valves pressure environment, also show here particularly favorable achieved with the present invention advantages, namely a fluid guide upon movement of the piston in the limited by the inventive web-like projections channels between anchor Shell surface and the armature guide tube.

It is also particularly preferred, the plurality of projections in such a way and circumferentially provided in the inner surface of the armature guide tube so that thereby takes place an axial centering of the armature. Not only does such a geometric-energetic optimization take place, but also the guide is optimized for the currentless state of the coil device.

While it is preferred, on the one hand, to extend the projections that are favorably web-shaped axially over the entire length of the guide tube, alternative embodiments are conceivable which cover only a partial region in the axial length or an interrupted one Form a line, ie represent a linear sequence of individual protrusions. It is favorable, however, that in any case at least a portion of the projections can cooperate with a portion of the armature.

Also, depending on the flow conditions and field of use or permissible air gap width, shape and profile of a to be selected, to be formed in the guide tube projection as desired; Here are suitable, a relatively large, or alternatively, a minimized bearing surface offering projecting cross-sections conceivable and encompassed by the present invention.

An essential advantage of the present invention is that, on the basis of a nonspecifically shaped armature guide tube, by suitable finishing during the formation (for example embossing) of the projections according to the invention, an adaptation to the circumferential geometry of a piston to be inserted can take place. This causes in an advantageous manner that low-priced mass production parts can be used as a starting material for the armature guide tube, which are adapted only by a further processing step, namely the shaping of the projections in the necessary precise processing to the anchor.

As a result, a solution to the problem of precise and reliable guidance of an armature in an armature guide tube for electromagnetic actuators with controlled air-gap conditions and favorable properties for fluid flows in the armature guide tube is combined by the present invention in a surprisingly simple and elegant manner.

Fig. 1:

einen schematischen Längsschnitt durch ein einseitig verschlossenes Ankerführungsrohr gemäß einer ersten bevorzugten Ausführungsform der vorliegenden Erfindung mit schematisch gezeigtem Anker;

Fig. 2:

eine Querschnittsansicht der Vorrichtung gemäß Fig. 1;

Fig. 3:

eine Perspektivansicht auf ein Ankerführungsrohr gemäß einem weiteren Ausführungsbeispiel der Erfindung;

Fig. 4:

einen Längsschnitt durch das Ankerführungsrohr der Fig. 3;

Fig. 5:

eine Perspektivansicht einer durch den Längsschnitt erhaltenen Hälfte des Ankerführungsrohres der Fig. 3, 4 und

Fig. 6:

ein weiteres Ausführungsbeispiel mit offenem, beidends durch Kerne verschlossenem Führungsrohr.

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 section through an unilaterally closed armature guide tube according to a first preferred embodiment of the present invention with schematically shown anchor;

Fig. 2:

a cross-sectional view of the device of FIG. 1;

3:

a perspective view of an armature guide tube according to another embodiment of the invention;

4:

a longitudinal section through the armature guide tube of Fig. 3;

Fig. 5:

a perspective view of a obtained by the longitudinal section half of the armature guide tube of Figs. 3, 4 and

Fig. 6:

a further embodiment with open, closed at both ends by cores guide tube.

With regard to the constructive realization of the periphery for the present invention, namely the production of an electromagnetic actuator with a held in a housing core with attaching armature guide tube and the armature guide tube surrounding the coil assembly is, for example, on the generic DE 102 35 644 A1 (There about Fig. 1 with associated description) referenced. However, as shown in Figs. 1 to 5, the armature guide tube (called a "magnet frame" in the prior art) is inserted through tube or sleeve-shaped and produced by deep drawing element 50 made of magnetically non-conductive material; Fig. 1 illustrates how this element is still closed at one end by a core portion 52, as well as in the sectional views of Fig. 1, 2, an anchor 54 is shown, which of six projections 56 which radially around the circumference of the tube 50 around are kept centered in a middle position. In the embodiment shown, the projections extend over virtually the entire length of the armature guide tube, which also has a closed bottom 58.

The embodiment of FIGS. 3 to 5 further illustrates in detail the constructive realization as a sleeve-shaped bush: By lateral pressing or impressing the axially extending in the longitudinal direction of the Ankersführungsrohrs projections 56 are formed, which also, by way of a fine machining and adaptation to the geometric conditions each to be used anchor element, in their dimensions, in particular their (the air gap between the armature and guide tube and the mobility of the armature determining) height can be adjusted.

Fig. 6 illustrates a variant of the above-described implementation forms; the closed bottom (reference numeral 58 in FIGS. 1 to 5) is replaced by a subsequently mounted core element 60. With appropriate fluid guidance through the cores, a 2/3-valve is hereby particularly well suited.

Claims (10)

Electromagnetic actuator with an armature (54) slidingly mounted in a preferably hollow-cylindrical armature guide tube (50) and movable by means of an electrical coil device,
characterized in that
the armature guide tube for realizing a sliding bearing for the armature inside has a plurality of protrusions (56) integrally formed around the circumference of the armature guide tube and formed integrally from the material of the armature guide tube. Apparatus according to claim 1, characterized in that the armature guide tube at one end forms a closed, preferably integrally formed bottom surface (58). Apparatus according to claim 1 or 2, characterized in that the projections (56) are formed so as to concentrically center the armature in the armature guide tube. Device according to one of claims 1 to 3, characterized in that the projections (56) extend web-like in the axial direction of the armature guide tube. Apparatus according to claim 4, characterized in that the projections extend over the entire axial length of the armature guide tube. Apparatus according to claim 4, characterized in that the projections extend in the axial direction over a portion of the armature guide tube so that in each position of the armature relative to the armature guide tube, a portion of a lateral surface of the armature cooperates with a portion of the projections. Device according to one of claims 4 to 6, characterized in that the projections represent a broken line along their extension direction. Device according to one of claims 1 to 7, characterized in that the projections in radial cross-sectional view form a semicircular, kreisabschnitts-, triangular or trapezoidal cross-sectional shape. Device according to one of claims 1 to 8, characterized in that the armature guide tube is made by deep drawing of a metal material and subsequent, anchor-specific molding of the projections of the thermoformed material. Use of the electromagnetic actuator according to any one of claims 1 to 9 for realizing a hydraulic or pneumatic valve.

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