EP3401936B1 - Electromagnetic adjustment device - Google Patents

Description

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

Such a device is, for example, a solenoid valve device from the DE 198 48 919 A1 known. In response to the energization of a (stationary) coil unit, an armature unit guided radially symmetrically in the coil interior opens and closes or closes a valve seat for the fluid to be controlled.

The armature unit (which generally has a cylindrical armature body) moves along the axial direction relative to a stationary core unit, which is part of the magnetic circuit and, through its design, influences the movement behavior, in particular a magnetic armature force of the armature unit. Specifically, the prior art device for influencing the movement behavior or force curve of the armature movement in the transition area between the (movable) armature unit and the (stationary) core unit shows a so-called control cone area (control area), which extends along the axial direction in an area of the Armature stroke (namely the area immediately after the armature unit is released from the core unit) influences the magnetic flux in the magnetic circuit between the armature unit, core unit and the other magnetic circuit elements involved.

The one from the DE 198 48 919 A1 Known control cone, here in the form of a ring shoulder, which is circumferentially flattened on the end face of the armature end face and a corresponding (radial) internal indentation on the part of the core unit, brings about an increase in the magnetic force of the armature in the described start-stroke range: by the shown overlap between armature unit and core area reduces the necessary magnetic flow through the core and armature by energizing the Winding, relative to a so-called flat cone, namely an embodiment of the transition between anchor unit and core unit without axial overlap or shortening of the working air gap. Accordingly, the magnetic field lines of the magnetic flux are closed primarily via the axial overlap, and consequently the magnetic force in this armature start stroke range is increased in a targeted manner.

By suitably designing this control area (control cone area), for example specifying an effective axial overlap, the movement behavior of the armature unit, in particular a course of the magnetic force along the movement stroke (movement stroke path), can be specifically influenced, for example, strengthening or weakening it comparatively or selectively.

However, the axial overlap of the armature unit and control unit in the control area, which is assumed to be known, also has potential disadvantages, in particular with regard to the wear and life characteristics of electromagnetic actuating devices designed in this way. This is because the axial overlap of the profile sections forming the control area on the armature or core side, in addition to the axial magnetic flux profile that is important for the armature movement, also creates a radial component (or normal component to the axial direction) of the magnetic flux profile, through the walls lying opposite one another of the profile sections formed air gap. This (in the case of radially symmetrical arrangements radial) magnetic force component 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, if the armature and core were exactly aligned with one another, the respective transverse force generated by the radial magnetic force component would be canceled in the center and thus cause compensation. However, this cannot be achieved in manufacturing and operating practice. Rather, the effect can be observed that the anchor unit (which is necessarily mounted with a radial clearance) within a surrounding guide (in the Frame of the existing game) tends to tilt, such an effect being additionally amplified by pressure springs or similar influences which do not quite affect the center of the anchor unit, furthermore manufacturing tolerances and other effects play a role.

Such an anchor unit (in the manner of a diametrical two-point support at respective inner positions of the anchor guide), which is at an angle in the scope of the clearance fit, initially leads to the core unit and anchor unit (and therefore the profile sections forming the control area) no longer exactly aligned, thus resulting in radial air gaps of different sizes in the circumferential direction (more precisely: sections of a circumferential air gap).

When the coil unit is energized and the resulting magnetic flooding in the control area results in unevenly high transverse magnetic forces in the air gap positions of different widths: Small radial air gaps generate relatively high magnetic transverse forces, and correspondingly large radial air gap sections produce small magnetic transverse forces. These then no longer compensate for each other in the radial direction, so that a resulting (radial) transverse force arises in the direction of the smallest air gap.

This acts as a normal force on the armature unit (which is supported with play) and, in accordance with the friction values of the tribological system consisting of the armature unit (or an armature sliding coating provided on the armature unit) and the armature guide, generates disadvantageous adhesive and sliding frictional forces.

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

In the case of electromagnetic switching devices with a long service life requirement (typically more than 100 million switching cycles), the described high magnetic lateral forces (normal forces) additionally a disadvantageously high surface pressure on the friction partners and thereby accelerate their tribological wear. This is particularly serious in pneumatic control applications (such as a pneumatic valve), since no lubrication or the like can reduce wear.

The consequence is a premature failure, especially in systems with a control cone area that are optimized in terms of size and energy consumption, especially if the anchor unit is provided with sliding coatings made of PTFE or MoS ₂ in an otherwise known manner and no (but again complex) slide film for guiding the anchor is used.

Furthermore, from the prior art US 2009/0051471 A1 known, which discloses an electromagnetic actuating device, wherein an armature unit movable in response to the energization of a stationary coil unit has an inner ring shoulder.

The object of the present invention is therefore to improve a generic electromagnetic actuating device with regard to its operating and wear behavior, in particular to reduce disadvantageous transverse or normal forces which promote tilting of the armature unit, and thus within the scope of the axially overlapping control area systems to combine favorable magnetic movement behavior and energy optimization with protection against unwanted wear due to disadvantageous friction.

The object is achieved by the electromagnetic actuating device with the features of the main claim; Independent protection in the context of the present invention is claimed by the use according to claim 8 and the method according to claim 9. 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 configured by designing the (magnetically) flux-effective cross sections of the first or second profile section such that, in the usual operating current causing the armature unit to move, the Flow and force compensation in the manner of a regulatory effect is achieved. More accurate According to the invention, the profile sections are designed in such a way that, in the event of tilting or deflection in a first region of the associated (radial) air gap, the increased transverse force (normal force) is compensated for by an associated magnetic flux (corresponding to the shortened air gap) Flooding) a magnetic resistance increases in this area. Typically, the profile sections are designed with regard to their flow-effective material cross-section so that in a correspondingly tilted state of the armature unit in the (radial) narrow area of the air gap, the resulting increased flooding leads to saturation, thus resulting in a flux-effective magnetic resistance, which then occurs leads to the magnetic flow being displaced or shifted to other areas of the air gap (back). This then has an effect which directly reduces the disadvantageous normal or transverse force, with the advantageous consequence of lower friction, correspondingly lower energy consumption and reduced wear.

Within the framework of the radial-symmetrical systems to be used with preference (i.e. an armature unit is guided within a coil unit surrounding it, the armature unit and core unit forming the respective profile sections in the form of circumferential elevations or depressions on the front side), the principle according to the invention leads to the fact that the usual, movement-typical operating currents for the coil unit there is an effective shift of the shear force-promoting magnetic flux from the area of the shortest air gap to other areas, since the magnetic saturation effect - correspondingly compensatory - offers a higher magnetic resistance.

The principle according to the invention can thus be realized by suitable configuration of the profile sections, which are then adapted to a flooding to be expected in typical operating conditions, in such a way that they specifically one with a radially opposite minimized air gap experienced magnetic flux resistance increase through magnetic saturation.

It is therefore advisable to give the first or second profile section a tooth or cam shape in longitudinal section with suitably conical inclination angles which, in the case of the advantageous radially symmetrical design, accordingly form as an annular projection (or interact with an appropriately adapted annular groove). Here, it is then necessary to optimize according to a particular requirement, with approximately flat cone angles having the advantage of inherently lower transverse forces, but at the same time, however, an effective axial overlap area also becomes smaller.

In general, it is also advantageous to design the respective cone angles of wall sections of the profile sections which are inclined relative to the central axis such that they run parallel to one another (based on an untilted or undeflected central position of the anchor unit), i.e. have the same angle (or, in the context of Manufacturing tolerances, a maximum angle of typically 5 ° as a difference).

According to the invention, a so-called inner cone is provided. A narrow cone ring (as a second profile section) of the core unit, which tends to become magnetically saturated due to its flow-effective cross-sectional design, dips into an internal ring shoulder (cone shoulder) at the front end of the anchor unit. Due to the narrow cone-shaped ring heel, the associated anchor section reacts sensitively to changes in the magnetic flux and generates compensating (uprighting) magnetic forces according to the above-described mechanism of action, which counteract the disadvantageous anchor inclination.

As a result, the present invention advantageously reduces disadvantageous friction between the armature unit and armature guide, so that energy and magnetic force are optimized, and wear is counteracted.

In particular, for practical implementation it is advantageous to implement (conventional) PTFE or MoS ₂ sliding coatings to meet the long service life requirements of electromagnetic actuating devices, such as valve devices, which reach the range of 100 million switching cycles or more, without requiring additional, costly measures requirement. It is particularly advantageous in the context of the invention and useful according to the further development that the (cylindrical) anchor unit does not have to be guided in a sliding film on the casing side in order to implement a so-called sliding film storage. Not only is the additional component-related and production-related expenditure reduced (the use of such a slide film also creates additional effort in the assembly), it is also effectively avoided that the parasitic air gap in the yoke region of the magnet device is unnecessarily increased by a slide film (or the thickness thereof) which in turn would have the disadvantage of poorer magnetic efficiency.

The present invention is thus advantageously suitable, for example, for realizing valve devices, more preferably pneumatic valve devices, but is not restricted to this field of application. Rather, the advantage of the present invention can be used favorably in all forms of realization of electromagnetic actuating devices, in which - due to the design or the play - a tilting or deflecting of the armature unit in an armature guide causes disadvantageous friction or wear and is used anyway to influence the magnetic force curve Profile elements in the control area (control cone area) can be dimensioned and used to implement the compensation behavior advantageous according to the invention.

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 result from the following description of preferred exemplary embodiments and from the figures; these show in

Fig. 1:

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

Fig. 2:

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

Fig. 3:

a longitudinal sectional view through a 2/2-way valve, realized by an electromagnetic actuating device to clarify the context of use of the present invention;

Fig. 4:

a half longitudinal sectional view analog Fig. 1 to illustrate one compared to the realization of the Fig. 1 disadvantageous design 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 is used in the motor vehicle sector and is provided with a cone control in the interaction between the anchor unit and the cone unit.

More specifically, the embodiment of FIG Fig. 3 , which is to be considered as belonging to the present invention with its features in the application context outside the control range, a housing 10 which carries a stationary winding 14 held on a coil carrier 12. Within the hollow cylindrical arrangement receiving an anchor guide tube 16 there is an anchor unit 20 along a longitudinal axis 18 of movement guided, which has a cylindrical outer contour, is supported against the force of a compression spring 22 in the axial direction from a stationary core region 24 and, opposite the core region 24, has a valve rubber insert 26 which is used to close a valve seat 28 in response to an axial Movement of the armature unit 20 is formed. The valve effect occurs between a supply connection 30 and a working connection 32. The armature unit 20 is provided on the shell side in an otherwise known manner by means of a PTFE or MoS ₂ sliding coating; there is no slide film for storing the anchor unit.

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

A control area (control cone area) in the magnetic transition between the core unit 24 and the sectionally hollow cylindrical armature unit 20 is in the enlarged, half longitudinal sectional view of FIG Fig. 1 illustrates, whereby, in the direct comparison, the embodiment of Fig. 4 shows a control area which is not optimized and advantageous in the sense of the invention.

Specifically, in the embodiment of the invention Fig. 1 the core region has an annular projection 34, which extends from the engagement-side end face of the core unit 24, which is provided inwards relative to an inner ring shoulder 36 of the associated engagement-side end region of the anchor unit 20 in the direction of the axis 18.

How the enlargement of the Fig. 2 This control area, in the state of the armature unit tilted to the right (or clockwise), clarified in this regard, is both the outward flank of the annular projection 34 and the inward flank of the annular groove 36, relative to the longitudinal axis 18, by a cone angle of approximately 8 ° inclined ( Within the scope of the invention, angles between 3 ° and 40 °, preferably between 5 ° and 20 °, more preferably between 7 ° and 15 °, have proven to be favorable and preferred). In the context of the invention, these cone angles are also configured identically, so that when the anchor unit is in a central position (ie untilted, in contrast to the illustration of FIG Fig. 2 ) the flank angles match.

Advantageously according to the invention, the one-piece, annular and conical projection 34 is now designed such that saturation then occurs in the event of a typical operating current through the coil unit 12, 14 (or a flooding thereby occurring in the transition region to the armature unit, in particular in the vertical air gap 40) occurs when this air gap (40 'in Fig. 2 ) becomes very narrow in the left-hand area, as a result of which the magnetic flux in this area and through the associated section of the projection 34 increases, which means that, due to the comparatively narrow ring diameter, the saturation takes place primarily here. According to the invention, this then advantageously leads to the fact that, for example in the (radially) opposite, right-hand area, a magnetic flooding increases over the air gap area 40 ″ there, due to the saturation in the left-hand area of the annular projection 34, magnetic flux is displaced or displaced outside of this area.

The result is a compensating force effect along an arrow 42 ( Fig. 2 ), corresponding to an upward or tilting force component returning in the transverse direction (normal direction) to the longitudinal axis 18. In this respect, the ring projection 34, which is designed here specifically to bring about saturation, forms the basis for a regulating or compensating system with regard to that as a profile section of the core unit lateral forces to be overcome or mitigated according to the task. In contrast, the comparative example of Fig. 4 , with a core-side profile section 44 and an associated armature-side ring shoulder 46 that - due to a larger flow-effective cross section of section 44 - none under operating conditions (typical operating current for the coil unit) Saturation occurs in section 44, hence a magnetic flux concentration in the vertical air gap between sections 44, 46 occurs at the smallest tilted distance and is also stable in this position. This results in disadvantageous strong frictional forces. It clarifies Table 1 below variant Air gap between anchor and core [mm] X-axis force [N] Y axis force [N] Z axis force [N] Fig. 4 0.15 -1.18 0.00 50.27 Fig. 1 0.71 0.05 62.40 Fig. 4 0.8 -1.94 -0.05 36,80 Fig. 1 -0.63 -0.03 42.65

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

The present invention is not limited to the specific embodiment shown, rather there are numerous ways and possibilities within the scope of the present invention of the control area by suitable profiling of the form cone-side and the anchor-side end section. The contour of the Fig. 2 (The ring protrusion on the core side is located radially on the inside) can be reversed, just as there can be a profiling on the armature side (or on both sides) that is optimized for fast magnetic saturation. In the present embodiment of the 1, 2 In addition, an outer circumferential ring shoulder 50 on the outer jacket side has proven to be advantageous, since this additionally reduced disadvantageous friction on the surrounding anchor guide.

Claims (8)

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 (20) 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 or the deflection acts on the anchor unit (20),
   the anchor unit (20) comprising a conical inner annular ledge for realizing the first profile section,
   characterized in that
   the anchor unit (20) forms a further circumferential annular ledge towards the core unit on the exterior.
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
   the first and the second profile section delimit the air gap via conical wall sections tilted towards the axial direction.
5. The device according to claim 4,
   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°.
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. A use of the electromagnetic positioning device according to any one of the claims 1 to 6 for realizing a valve device, in particular a pneumatic valve device, in which a fluid flow is controlled by the movement the anchor unit.
8. A method for operating an electromagnetic positioning device according to any one of the claims 1 to 6,
   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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