EP2630647B1 - Electromagnetic actuating apparatus - Google Patents

Description

The present invention relates to an electromagnetic actuator according to the preamble of the main claim, as shown in the US 2009/051471 A1 is known.

An electromagnetic valve device is out of the DE 198 48 919 A1 known. In response to the energization of a (stationary) coil unit moves a radially symmetrically guided inside the coil armature unit and opens or closes a valve seat for the fluid to be controlled.

Along the axial direction, the armature unit (having a cylindrical armature body) moves relative to a stationary core unit, which is part of the magnetic circuit and influences the movement behavior, in particular a magnetic armature force of the armature unit, by its design. Specifically, the device for influencing the movement behavior or force curve of the armature movement referred to in the prior art in the transition region between the (movable) armature unit and the (stationary) core unit has a so-called control cone area (control area) which extends along the axial direction in a region of the armature Ankerhubes (namely the area immediately after the release of the armature unit of the core unit) affects the magnetic flux in the magnetic circuit between the armature unit, core unit and the other magnetic circuit elements involved.

The from the DE 198 48 919 A1 Known control cone, here in the form of an end of the anchor end face rotating, outwardly flattened annular shoulder and a corresponding (radially) inner indentation on the side of the core unit, causes here about an increase in the magnetic force of the armature in the described start-stroke range: By the shown overlap between anchor unit and core area reduces the necessary magnetic flux of core and armature by energizing the Winding, relative to a so-called flat cone, namely an embodiment of the transition between the anchor unit and core unit without axial overlap or shortening of the working air gap. Accordingly, the magnetic flux lines of the magnetic flux are primarily closed via the axial overlap, thus selectively increasing the magnetic force in this armature start stroke range.

By suitable design of this control area (control cone area), such as a specification of an effective axial overlap, so can the movement behavior of the armature unit, in particular a course of the magnetic force along the movement stroke (Bewegungshubwegs) specifically influence, strengthen or weaken comparatively or pointwise.

However, the axial overlap of armature unit and control unit in the control area, which is to be presupposed as known, also brings potential disadvantages, in particular with regard to the wear or service life characteristics of electromagnetic actuators designed in this way. Thus, by the axial overlapping of the control region forming profile sections on anchor or core side, in addition to the important for the armature movement axial magnetic flux, also a radial component (or normal component to the axial direction) of the magnetic flux profile, by the wall between facing each other the profile sections formed air gap. This magnetic force component (which is radial in the case of radially symmetrical arrangements) causes disadvantageous magnetic transverse forces, which have a disadvantageous effect in practice or in particular in connection with frequent movement cycles or long operating times. Thus, with exact alignment of armature and core to each other, the respective lateral force generated by the radial magnetic force component would be canceled in the center and thus cause a compensation. However, this can not be achieved in manufacturing and operating practice. Rather, the effect is observed that the (necessarily mounted with a radial clearance) anchor unit within a surrounding guide (im Frame of the existing game) tends to tilt, with such an effect is further enhanced by not quite the center of the anchor unit acting compression springs or the like influences, also play manufacturing tolerances and other effects a role.

Such, in the context of the clearance fit obliquely in the anchor guide anchor unit (in the manner of a diametrical two-point support at respective inner positions of the armature guide) then leads first to the core unit and armature unit (and thus the control area forming profile sections) no longer exactly aligned, thus set in the circumferential direction different sized radial air gaps (more precisely: sections of a circumferential air gap).

Upon energization of the coil unit and thereby effected magnetic flux in the control area correspondingly unequal high magnetic transverse forces arise in the different width air gap positions: Small radial air gaps generate relatively high magnetic transverse forces, correspondingly large radial air gap sections small magnetic transverse forces. These then no longer compensate each other in the radial direction, so that a resulting (radial) transverse force arises in the direction of the smallest air gap.

This acts on the (with game stored) armature unit as a normal force and generated according to the friction coefficients of the tribological system of anchor unit (or provided on the anchor unit anchor sliding coating) and the anchor guide disadvantageous adhesive and Gleitreibkräfte.

These initially have a negative effect on the balance of forces of the magnet and lead to an (unnecessarily) increased magnetic force requirement, and thus a larger magnetic space.

In electromagnetic switching devices with a high lifetime requirement (typically more than 100 million switching cycles), the described high magnetic transverse forces (normal forces) generate In addition, a disadvantageous high surface pressure on the friction partners and thereby accelerate their tribological wear. This is particularly serious, for example, in pneumatic actuating applications (such as a pneumatic valve), since no lubrication or the like can have a wear-reducing effect.

The consequence is a premature failure, especially in systems with control cone area optimized in size and in energy consumption, especially if the armature unit is provided with sliding coatings of PTFE or MoS ₂ in an otherwise known manner and no (itself expensive) sliding foil for guiding the armature is used.

Object of the present invention is therefore to improve a generic electromagnetic actuator with respect to their operating and wear behavior, in particular to reduce adverse transverse or normal forces that promote tilting of the armature unit, and so in the context of an axially overlapping control area systems to combine favorable magnetic movement behavior and energy optimization with protection against undesired wear due to adverse friction.

The object is achieved by the electromagnetic actuator with the features of the main claim; independent protection in the context of the present invention is claimed by the use according to claim 9 and the method according to claim 10. Advantageous developments of the invention are described in the subclaims.

In an advantageous manner according to the invention, the control area (control cone area) between the armature unit and the core unit is set up by configuring the (magnetic) flow-effective cross sections of the first or second profile section such that in the usual operating current for the coil unit causing the armature unit to move Flow and force compensation in the nature of a regulatory effect is achieved. More accurate According to the invention, the profile sections are configured such that in the case of a tilting or a deflection in a first region of the associated (radial) air gap, the increased transverse force (normal force) is compensated for by the fact that, for an associated magnetic flux (corresponding to the shortened air gap). Flooding) a magnetic resistance in this area increases. Typically, the profile sections are designed with respect to their flow-effective material cross-section so that it comes in a corresponding tilted state of the armature unit in the (radial) narrow region of the air gap through the resulting increased saturation saturation, thus creating a flux-effective magnetic resistance, which then This leads to the fact that the magnetic flux is displaced or displaced into other areas of the air gap (back). This then has a directly the adverse normal or lateral force reducing effect, with the advantageous result of lower friction, correspondingly lower energy consumption and reduced wear.
In the context of the preferably radially symmetrical systems to be used (ie, an armature unit is guided within a surrounding coil unit, the armature unit and the core unit forming the respective profile sections in the form of circumferential elevations or depressions), the principle according to the invention results in the usual, movement-typical operating currents for the coil unit, an effective displacement of the lateral force-promoting magnetic flux from the region of the shortest air gap is carried out in other areas, since the magnetic saturation effect - corresponding compensatory - offers a higher magnetic resistance.
Thus, the inventive principle can be realized by suitable design of the profile sections, which then, adapted to be expected in typical operating conditions flooding, designed so that they learn at radially minimized minimized air gap targeted magnetic flux resistance increase by magnetic saturation. This makes it advisable to give the first and second profile section a tooth or cam shape with suitably conical angles of inclination, which in the case of the advantageous radially symmetrical design arise correspondingly as an annular projection (or interact with a correspondingly adapted annular groove). Here is then to optimize according to a respective requirement, with about flat cone angle inherently have the advantage of lower lateral forces, but at the same time so that an effective axial coverage area is smaller.
In general, it is also advantageous to configure respective cone angles of wall sections of the profile sections which are inclined relative to the central axis so that they (in relation to an undeflected or undeflected middle position of the anchor unit) run parallel to one another, ie have the same angle (or, in the context of FIG Manufacturing tolerances, do not exceed a maximum angle of typically 5 ° as the difference).
Particularly advantageous, an embodiment has been found to be a so-called inner cone. A narrow conical ring (as a second profile section) of the core unit, which tends to saturate magnetically due to its flux-effective cross-sectional configuration, enters an inner annular shoulder (cone shoulder) at the front end of the armature unit. Due to the narrow cone-shaped annular shoulder, the associated armature section reacts sensitively to changes in the magnetic flux and, in accordance with the above-described mechanism of action, generates compensating (righting up) magnetic forces which counteract the disadvantageous armature skew.
As a result, disadvantageous friction between the armature unit and the armature guide is advantageously reduced by the present invention, thus optimizing energy and magnetic force, and counteracting wear. In particular, it is advantageous for the practical implementation, with (conventional) PTFE or MoS ₂ - sliding coatings high To meet lifetime requirements for electromagnetic actuators, such as valve devices, which reach the range of 100 million cycles or more, without the need for separate, additional costly measures. Thus, it is particularly advantageous in the context of the invention and further useful according to the development that the (cylindrical) armature unit does not have to be guided on the shell side in a sliding foil for realizing a so-called sliding foil bearing. Not only is the additional component engineering and manufacturing expense reduced (the use of such a sliding produces additional effort during assembly), is also effectively avoided that unnecessarily increased by a sliding film (or the thickness thereof) of the parasitic air gap in the yoke region of the magnetic device which in turn would have the disadvantage of a poorer magnetic efficiency.

Thus, the present invention is suitable in a favorable manner as for the realization of valve devices, more preferably pneumatic valve devices, but is not limited to this field of application. Rather, the advantage of the present invention can be used favorably in all forms of implementation of electromagnetic actuators, in which - caused by design or play - tilting or deflecting the armature unit in an armature guide causes adverse friction or wear and used anyway to influence the magnetic force curve Profile elements in the control area (control cone area) can be dimensioned and used for realizing the invention advantageous compensation behavior.

Fig. 1:

einen schematischen hälftigen Längsschnitt durch die wesentlichen magnetischen Funktionskomponenten der elektromagnetischen Stellvorrichtung gemäß einer ersten Realisierungsform der Erfindung;

Fig. 2:

eine Detailansicht des Steuerbereichs mit den einander gegenüberstehenden Profilabschnitten der Ankereinheit bzw. der Kerneinheit sowie eingezeichneten Messpunkten für eine Simulation;

Fig. 3:

eine Längsschnittansicht durch ein 2/2-Wegeventil, realisiert durch eine elektromagnetische Stellvorrichtung zum Verdeutlichen des Einsatzkontexts der vorliegenden Erfindung;

Fig. 4:

eine hälftige Längsschnittansicht analog Fig. 1 zum Verdeutlichen einer gegenüber der Realisierung der Fig. 1 nachteiligen Ausgestaltung der Profilabschnitte des Steuerbereichs und

Fig. 5:

ein Vergleichsdiagramm in Form einer Kraft-Weg-Kennlinie des Ausführungsbeispiels der Fig. 1 relativ zum Vergleichsbeispiel der Fig. 4.

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

Fig. 1:

a schematic half-longitudinal section through the essential magnetic functional components of electromagnetic actuator according to a first embodiment of the invention;

Fig. 2:

a detailed view of the control area with the opposing profile sections of the anchor unit or the core unit and marked measuring points for a simulation;

3:

a longitudinal sectional view through a 2/2-way valve, realized by an electromagnetic actuator for illustrating the operational context of the present invention;

4:

a half-longitudinal view analog Fig. 1 to clarify a relation to the realization of the Fig. 1 disadvantageous embodiment of the profile sections of the control area and

Fig. 5:

a comparison diagram in the form of a force-displacement characteristic of the embodiment of the Fig. 1 relative to the comparative example of Fig. 4 ,

The Fig. 3 illustrates the application context of the present invention; shown is a structurally otherwise known 2/2-way valve, which finds use in the automotive sector and is provided in cooperation between the anchor unit and cone unit with a cone control.

More specifically, the embodiment of the Fig. 3 which is to be deemed to be associated with its features in the context of use outside the control area as belonging to the present invention, a housing 10 which carries a held on a bobbin 12 stationary winding 14. Within the hollow cylindrical, an armature guide tube 16 receiving arrangement along an axis of movement 18, an armature unit 20 is guided, which has a cylindrical outer contour, against the force of a compression spring 22 from a stationary core portion 24 in the axial direction supported and, opposite to the core portion 24, a valve rubber insert 26 which is for closing a valve seat 28, in response to an axial movement of the armature unit 20 is formed. The valve effect arises between a supply connection 30 and a working connection 32. The anchor unit 20 is provided on the shell side in an otherwise known manner by means of a PTFE or MoS ₂ sliding coating; a sliding foil for the storage of the anchor unit does not exist.

In response to an energization of the winding 14, the armature unit 20 moves along the longitudinal axis of movement 18 in the vertical direction (Z in Fig. 3 ). The orthogonal to this axis directions X, Y are drawn accordingly.

A control range (control cone area) in the magnetic transition between the core unit 24 and the partially hollow cylindrical armature unit 20 is in the enlarged, half-longitudinal view of the Fig. 1 illustrates, wherein, in the immediate comparison, the embodiment of Fig. 4 shows a not optimized in the context of the invention and advantageous control range.

Specifically, in the preferred embodiment of the Fig. 1 the core portion has an annular protrusion 34 extending from the engagement-side end surface of the core unit 24, which is provided inwardly toward the axis 18 relative to an inner annular shoulder 36 of the associated engagement-side end portion of the armature unit 20.

Like the cropping of the Fig. 2 In this regard, in this regard, both the outward flank of the annular projection 34 and the inward flank of the annular groove 36, relative to the longitudinal axis 18, are a cone angle of approximately eight ° inclined (being within the scope of the invention, angle between 3 ° and 40 °, preferably between 5 ° and 20 °, more preferably between 7 ° and 15 °, as favorable and preferred to have). In the context of the invention, moreover, these cone angles are configured identically, so that in the case of a central position of the armature unit (ie untilted, in contrast to the illustration of FIG Fig. 2 ) the flank angles match.

Advantageously in accordance with the invention, the integrally abutting, ring-shaped and conical projection 34 is now configured such that at a typical operating current through the coil unit 12, 14 (or a flux occurring in the transition region to the armature unit, in particular in the vertical air gap 40), then saturation occurs when this air gap (40 'in Fig. 2 ) in the left-hand area becomes very narrow, thereby increasing the magnetic flux in this area and the associated portion of the projection 34, which then, due to the comparatively narrow ring diameter, here the saturation takes priority. In accordance with the invention, this advantageously leads to a magnetic flux being increased over the local air gap area 40 "in the (radially) opposite, right-hand region, due to which saturation in the left-hand region of the annular projection 34 displaces or displaces magnetic flux outside this region.

The result is a compensating force action along an arrow 42 (FIG. Fig. 2 In this respect, the annular projection 34, which is designed here in particular to bring about saturation, as the profile section of the core unit forms the basis for a regulating or compensating system with respect to FIG According to the task to be overcome or mitigated transverse forces. In contrast, the comparative example illustrates the Fig. 4 , with a core-side profile section 44 and an associated armature-side annular shoulder 46 that - due to a larger flow-effective cross-section of the section 44 - under operating conditions (typical operating current for the coil unit) no saturation occurs in the section 44, thus a magnetic flux concentration in the vertical air gap between sections 44, 46 in the smallest tilted Distance occurs and is stable even in this position. Disadvantageous strong frictional forces are the result here. It clarifies the following Table 1 variant Air gap between anchor and core [mm] Force X-axis [N] Force Y-axis [N] Force Z-axis [N] Fig. 4 -1.18 0.00 50.27 Fig. 1 0.15 0.71 0.05 62.40 Fig. 4 -1.94 -0.05 36,80 Fig. 1 0.8 -0.63 -0.03 42.65

In connection with the Fig. 5 as a force-displacement characteristic of the juxtaposition of Fig. 1, Fig. 4 how effectively the adverse lateral force can be reduced; The measured values in Table 1 are derived from a three-dimensional simulation with anchor slanting using the positions A to H in Fig. 2 , It can be seen that a reduction of the armature transverse force of approx. 30% or an upright magnetic force (positive sign) can be achieved (with armature inclination in the direction of the X axis), both with a short and relatively long armature stroke (FIG. 0.15 mm or 0.8 mm), in direct comparison of the cone designs of Fig. 1 relative to the comparative example of Fig. 4 ,

The present invention is not limited to the specific embodiment shown, but there are numerous ways and possibilities, in the context of the present invention, the control area by appropriate profiling of the cone-side and the armature-side end portion form. It can be about the contour of the Fig. 2 (Ring projection on the core side is radially inward) be reversed, just as an optimized for fast magnetic saturation profiling on anchor side (or both sides) may be present. In the present embodiment of Fig. 1, Fig. 2 In addition, an end-coat side, outer circumferential annular shoulder 50 has been found to be advantageous, as this could additionally reduce adverse friction on the surrounding anchor guide.

Claims (9)

1. An electromagnetic positioning device having an anchor unit (20), which is moveable in an axial direction (18) around a movement stroke relative to a stationary core unit (24) and in reaction to a spool unit (14) being energized using an operating current and which, on one end, magnetically interacts with the core unit via a control area overlapping axially along the movement stroke at least in sections, said control area comprising a first profile section (34, 44) as a section of the anchor unit and, as a section of the core unit, a second profile section (36, 46) having an air gap (40) realized therebetween and realizing an expansion perpendicular to the axial direction,
   a cross section of the first and of the second profile section, which is flow-effective for a magnetic flow of the energization using the operating current flowing via the air gap, being realized such that in response to a reduction of the air-gap expansion caused by the anchor unit being tilted and/or deflected from the axial direction, a magnetic flow resistance of the first and/or the second profile section increases in the area of the reduction via magnetic saturation and a force opposing the tilt and/or the deflection acts on the anchor unit,
   characterized in that
   the first and the second profile section delimit the air gap via conical wall sections tilted towards the axial direction.
2. The device according to claim 1,
   characterized in that
   the anchor unit and the core unit are realized radially symmetrical around a middle axis extending along the axial direction and in that the first and/or the second profile section preferably abut in one piece made of an anchor or core body and are realized so as to radially extend,
   by being tilted or inclined, the air gap radially extending between the first and the second profile section is reduced in a first air-gap area and is expanded in an air-gap area oppositely disposed with respect to the middle axis.
3. The device according to claim 1 or 2,
   characterized in that
   the first and/or the second profile section comprise(s) a longitudinal tooth and/or cam shape, which are realized as an annular protrusion when the anchor and the core unit are realized radially symmetric.
4. The device according to any one of the claims 1 to 3,
   characterized in that
   a cone angle of the wall sections of the first and/or the second profile section are realized such that the wall sections extend parallel to each other when the middle position of the anchor unit is not tilted or deflected and/or that an angle realized between the wall sections is < 5°, preferably less than < 3°.
5. The device according to any one of the claims 1 to 4,
   characterized in that
   one of the profile sections is realized as a radially extending, longitudinal and conical annular protrusion, which interacts with the other profile section realized as a radially extending, conical annular groove and/or annular ledge.
6. The device according to any one of the claims 1 to 5,
   characterized in that
   the anchor unit comprises a conical inner annular ledge for realizing the first profile section and forms a further circumferential annular ledge towards the core unit on the exterior.
7. The device according to any one of the claims 1 to 6,
   characterized in that
   the anchor unit comprising a cylindrical anchor body does not comprise a pestle guide or a pestle mount and/or is mounted without film means, in particular without a sliding film, on the exterior.
8. A use of the electromagnetic positioning device according to any one of the claims 1 to 7 for realizing a valve device, in particular a pneumatic valve device, in which a fluid flow is controlled by the movement the anchor unit.
9. A method for operating an electromagnetic positioning device according to any one of the claims 1 to 7,
   characterized by the following steps:

   • energizing the spool unit for causing a movement of the anchor unit in the axial direction,

   • causing a force, in particular a transverse force or a normal force, acting on the anchor unit against the tilting or the deflection from the axial direction upon an axial overlapping between the anchor unit and the core unit in the control area.

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