EP1070198B1 - Electromagnetic actuator with laminated armature - Google Patents

Abstract

The invention relates to an electromagnetic actuator for actuating a control member, comprising at least one electromagnet formed by a yoke element presenting a pole face and having a coil; and an armature element which via a guide pin can be moved back and forth in relation to the pole face and presents an armature plate (1). Said armature plate is immovably joined to a guide pin (2) and has two cover plates (3, 4) between which a laminated stack (5) consisting of a plurality of immovably interconnected laminations (6) is arranged, said laminations being aligned perpendicular to the cover plates (3, 4) and joined to same.

Description

An electromagnetic actuator for actuating an actuator works in such a way that one in its energization is provided controllable electromagnet whose magnetic force acted upon energization of an anchor, with the actuated Actuator communicates. In general, one is Return spring provided, the set in de-energized Electromagnet the anchor or related thereto Actuator holds in a first switching position and at Energizing the electromagnet against the force of the return spring moved to the second position by the magnetic forces is held and in this second position, as long as the electromagnet is energized.

To influence the movement speed of the armature its approach to the pole face of the electromagnet one hand, but also when loosening the anchor from the pole face the Stromlossetzen the electromagnet on the other hand is a rapid possibility of changing the magnetic force desirable. This fast force change or magnetic field change act but counteract eddy currents. The formation of eddy currents in the electromagnet, however, can be minimized by that the yoke body is made of laminated material, so that at energization of the electromagnet, in particular in the Phase, when the anchor is still far away, a faster Field construction takes place (DE-A-35 00 530). In the final phase of the approach However, the armature is the electromagnet in his Effect increasingly influenced by the anchor. Because the anchor but so far consisted of massive iron, which act in the anchor resulting eddy currents of a rapid field change and thus a quick change of power counter. The same applies to the so-called detachment process. Becomes the solenoid is de-energized, so are in a geblechtem Yoke body only small eddy currents present. By the in the made of solid iron anchor even after shutdown the power supply to the electromagnet is still flowing Eddy currents is the detachment process of the armature by the so-called "sticking" delayed. That leads to fast Switching to disadvantages and affects a reproducible Control of the actuator. When using such Actuators for actuating the gas exchange valves a reciprocating internal combustion engine are also next high Switching frequencies also high mechanical stresses to dominate anchor and yoke body.

The above-described disadvantages are according to the invention solved by an electromagnetic actuator for Actuation of an actuator, with at least one electromagnet, by a yoke body having a pole face is formed with a coil, and with respect to the pole face can be moved back and forth via a guide pin Anchor member having an anchor plate, which with a Guide pin is firmly connected and the two cover plates between which a plate pack of a plurality arranged by firmly interconnected laminations is aligned perpendicular to the cover sheets and associated with these. By connecting the cover plates with the formed of a plurality of laminations Disc pack results in a stable anchor plate, which too the mechanical stresses of an electromagnetic Actuator with high frequency switching frequency withstands. Due to the lamellar structure, it is possible a reduction to achieve eddy current formation. This results in the Advantage of a faster field change when changing the current on the electromagnet and thus also a faster influence the anchor movement. By reducing the Eddy current formation in the armature is for example the possibility in the approach phase of the anchor to the pole face regulate the energization so that only one path-dependent, low excess of force over the restoring force of the spring is present and thus lower impact speeds be achieved. When the anchor hits the Pole surface then the current to the electromagnet can be increased, so that the anchor is kept safe and not again bounces. The armature will then be against the force of the return spring with a low magnetic force on the pole face held. Another advantage of reduced eddy currents at fitting anchor also results in methods for so-called "Overlay detection", i. the recognition of the request of the anchor on the pole face. While not so far avoiding eddy currents at a massive anchor it practically made impossible, from the clock frequency of a clocked Holding current or from the evaluation of the temporal Curves of current and / or voltage a clear signal derive since the change of the differential inductance and the change of eddy current components in the anchor just in the here interesting areas of operation at least partially compensated, leads to the reduction of eddy current formation in anchor to unique and reproducible signals, that for the regulation and / or control of the current supply of the electromagnet are usable.

The detachment process is also due to the reduction of eddy current formation favorably influenced. While at a massive Anchor by the even after switching off the coil current flowing eddy currents delayed the detachment process is achieved by a low-turbulence anchor according to the invention the magnetic force reduction greatly accelerated and the so-called Gluing time reduced.

In one embodiment of the invention it is provided that the Cover plates provided on at least one edge with an angling are the associated end face of the plate pack covered. The bend can be provided in this case be that both cover sheets have the shape of an L-profile and offset by 180 ° to each other placed on the disk pack are so that the bends each face the front Cover by the end edges of each sheet metal lamellae be formed. One or both covers can formed by the arrangement of bends as U-profiles be. If only one cover plate is designed as a U-profile and the other cover plate is used as a flat plate, then the disk set preferably so with the U-shaped cover plate connected, that in turn covers the faces be formed by the end edges of the individual laminations become. The flat cover plate is then on the other Side of the disk pack on. Are both cover plates with bends provided, the cover plates a U-shaped Profile cross-section give, then the cover plates by 90 ° offset from one another connected to the disk set, so that the narrow front edges of the disk pack on all sides of the bends are covered and so the disk pack of The cover sheets is covered in a can.

In an embodiment of the invention is further provided that the Lamella package at least at the transverse to the orientation of the Laminated sheets running edges welded to the cover sheets is. This not only results in an end-side firm connection of the laminations with each other, but also a firm connection with the cover sheets. If the cover sheets are provided with bends that the end edges of the Covering lamellae, it may be appropriate, before the Attaching the cover plates, the laminations to the transverse to her Orientation extending faces of the disk pack to weld, so that even the disk pack for a forms stable body in itself.

In a further advantageous embodiment of the invention provided that the individual laminations Durchprägungen each having a cup-shaped on a side slats Deepening and on the other side slats a wart-shaped Make up raise and that the raises one Sheet metal plate in the recess of the adjacent lamination engage and the laminations by pressing to a disk set are positively connected with each other. By such a stamped package are the individual laminations held by clamping action and it results in the transverse direction a positive connection of the individual laminations with each other, the effective over the entire width of the anchor plate is, so that the disk set in an even higher dimensional stability receives.

In a further embodiment of the invention is provided that the laminations of the disk pack by at least two transverse bolts firmly connected are. The bolts can be used as bolts or as rivets be executed. Here are the individual laminations provided with a through hole, so that the disk pack connected to a complete unit via the bolts is. This embodiment can also be in a stanzpaketierten Disc set can be used so that the rigidity of the Anchor plate is not achieved only over the bolts.

In an expedient further embodiment of the invention is provided that the guide pin a guide shaft and a Has a larger diameter bolt head and that the Bolt head passed through the hole in the disk pack is and soldered in the contact area with the disk pack is. As a result, the necessary for a stable solder joint large contact surface between the guide pin on the one hand and the bore in the anchor plate, on the other hand. This is a solid connection between the soft magnetic iron material existing lamellar package with a made of a heat-treatable steel material To produce guide pin. This is expediently used a copper-based solder.

In an advantageous embodiment of the invention is provided here, that the bolt head at least one twist to the Recording a solder has. The twisting can take the form of a Be made chamfering of the head surface of the bolt and / or in the form of a circumferential groove on the cylindrical Peripheral surface of the bolt head. The chamfer and / or the groove must be dimensioned in their cross-section so that the required Lotmenge by the on or inlaid Lot to Available. As opposed to an anchor plate made of solid Material the cylindrical wall of the mounting hole for the Bolt head with a disc pack corresponding to minimum Having columns, it may be appropriate, both a frontal Chamfering as well as a groove on the cylindrical peripheral surface to provide and in both places according to Lot to apply, so that in any case a continuous layer of solder between the bolt head and the bore of the anchor plate is available.

It is basically known, in each case the yoke body of the To design electromagnets as disk pack, d. H. a Variety of laminations to connect a package together wherein the laminations by transverse Welds are firmly connected, as in DE-A-36 37 411 described or via continuous rivets to a package as known from EP-A-0 923 089 is. However, it has been found that due to the thermal Actions when welding the laminations one Material embrittlement in the area of the welds occurs. Furthermore influences the thermal effect during welding the magnetic properties of the sheet material disadvantageous d. H. the magnetic reversal when switching on and off the energization of the coil is delayed.

It has now been shown that the design of the Anchor element used punching package also advantageous in the design of the yoke body of the electromagnet.

Accordingly, it is proposed in an embodiment of the invention an electromagnetic actuator with at least one electromagnet, by having a pole face Yoke body is formed with a coil, and with respect to a on the pole face via a guide pin back and forth Anchor element, in particular with a yoke body, the consists of a variety of laminations, each with several impressions are provided on a slat surface wart-shaped elevations and on the other lamellar surface form corresponding cup-shaped depressions, wherein the elevations each of a lamination in the wells engage the adjacent lamination and the laminations fixed by pressing to a disk set form fit connected to each other, wherein the yoke body on portions its surface is enclosed by a housing.

In such a constructed electromagnet results for the yoke body a disk pack with high packing density and the positive connection formed by the stamped package Laminations with each other a yoke body with high dimensional stability and fatigue strength. Especially those in the plane the laminations, so transversely to the impressions mechanical Force effects are reliably absorbed. The Indentations can be provided here in areas in which particularly high forces occur during operation.

The disc pack can also be screwed through appropriate or riveted bolts are held together. Especially it is advantageous, however, if that is the disk set Enclosing housing by encapsulation or encapsulation of the disk pack will be produced. It is also possible to use the plate pack gluing in a prefabricated housing, wherein the adhesive can have thermally conductive properties. This will be the disc pack held in the housing without play.

For example, plastics can be considered as material here. which have a corresponding temperature resistance, if such an actuator for actuating a gas exchange valve used on a reciprocating internal combustion engine becomes.

However, metals can also be used, for example Aluminum alloys. It is expedient if the metal if necessary by appropriate additions, a reduced electrical Conductivity of the housing material has.

Fig. 1

in perspektivischer Ansicht einen Anker mit zwei ebenen Deckblechen,

Fig. 2

in perspektivischer Ansicht einen Anker mit abgewinkelten Flächen,

Fig. 3

eine Stirnansicht des Ankers gem. Fig. 1, gesehen in Richtung des Pfeiles A,

Fig. 4, 5, und 6

unterschiedliche Ausbildungen der Deckfläche,

Fig. 7

einen Schnitt gem. der Linie VII-VII in Fig. 1,

Fig. 8

eine Schnittdarstellung gem. Fig. 7 mit einer anderen Form des Führungsbolzens,

Fig. 9

in vergrößertem Maßstab einen Schnitt gem. der Linie IX-IX in Fig. 1,

Fig. 10

einen elektromagnetischen Aktuator zur Betätigung eines Gaswechselventils in Seitenansicht, teilweise im Schnitt,

Fig. 11

eine Aufsicht auf eine Blechlamellen eines Jochkörpers mit Durchprägungen.

The invention will be explained in more detail with reference to schematic drawings of exemplary embodiments. Show it:

Fig. 1

in perspective view an anchor with two flat cover plates,

Fig. 2

in perspective view an anchor with angled surfaces,

Fig. 3

a front view of the anchor gem. 1, seen in the direction of arrow A,

4, 5, and 6

different formations of the top surface,

Fig. 7

a cut acc. the line VII-VII in Fig. 1,

Fig. 8

a sectional view acc. 7 with a different shape of the guide pin,

Fig. 9

on an enlarged scale a section acc. the line IX-IX in Fig. 1,

Fig. 10

an electromagnetic actuator for actuating a gas exchange valve in side view, partly in section,

Fig. 11

a plan view of a lamination of a yoke body with impressions.

The illustrated in Fig. 1 anchor for an electromagnetic Actuator consists of an anchor plate 1, which with a Guide pin 2 is firmly connected. The anchor plate 1 has two cover plates 3, 4, between which a disc pack 5 on a variety of tightly interconnected laminations is arranged perpendicular to the cover plates 3, 4th aligned and connected to these. Fig. 3 shows a End view in the direction of arrow A in Fig. 1 in larger Scale. In Fig. 3, this is from a variety of Single lamellae 6 composite disc pack 5 to recognize.

In Fig. 2, a modified embodiment is also in shown in perspective view. The cover plates 3, 4 are each provided at the edge with bends 7 and 8, the transverse to the front edges of the laminations (not here shown) of the enclosed plate pack 5 run and cover them up.

The bending of the cover plates 3 and 4 can now in different Form be made. In Fig. 4 is an embodiment shown, in which the upper cover plate 3 planar is formed while the lower cover plate 4 at both edge sides with bends 7, 8 is provided and thus has a U-shaped cross-section.

Fig. 5 shows a modified embodiment in which both Cover plates 3, 4 at the edge with only one bend 7 or 8 are provided so that both cover sheets an L-shaped cross-section exhibit. The two cover plates 3, 4 are reversed arranged to each other, so that in each case the bend a cover plate covers one end face of the disk pack 5.

In the embodiment according to. 6 are both cover plates 3rd and 4 at both edges with bends 7, 8 provided, so that they each have a U-shaped cross-section. Both Cover plates 3, 4 are offset by 90 ° to each other on the disk set 5 attached, so that all faces of the disk pack are covered by the bends of the cover plates and the plate pack is enclosed like a can.

The connection of the individual laminations 6 with each other and the compound of the formed from the laminations 6 Disc pack 5 with the cover plates 3, 4 can now in different Be carried out manner. In the in Fig. 1 illustrated embodiment, the individual louvers are together with the two overlying cover plates 3, 4 respectively in Edge region of the two opposite end faces 9 connected together by welding or soldering, so that through the seam 21, both the individual laminations with each other as well as the two cover plates 3, 4 with the disk pack 5 are firmly connected (see Fig. 7). A preferred Type of connection will be described with reference to FIG. 9.

In Fig. 2, an embodiment is shown, in which the individual laminations of the disk pack by two transversely extending bolts 10 are firmly connected. The Bolt 10 are in this case by corresponding holes 11 (see. Fig. 7) inserted through in the laminations 6. Bolts can be designed as bolts or as rivets be. For both forms of connection of laminations to a disk pack, it is expedient, as shown in Fig. 9, by a so-called stamped packetization of the laminations 6 a positive connection between the adjacent laminations to effect. Here are the individual laminations 6 provided with one or more indentations 6.1, on a slat side a cup-shaped depression 6.3 and on the other side of the lamella a corresponding wart-like Make up increase 6.2. Be the individual laminations 6 assembled into a lamella stack, each engages the increase 6.2 of a lamination in the recess 6.3 of next sheet lamination, so that when pressed of the lamella stack, a fixed lamella package with high packing density is formed. The laminations 6 are interconnected held by clamping action. In the direction of the Durchpärgungen 6.1 results in a positive connection that over the Whole width is effective and by the relative movements of the Laminations are prevented against each other.

As can also be seen from FIG. 7, the lamellae 6 are interconnected on the one hand and with the cover plates 3 and 4 on the other in each case via seams 21 in the edge region of the end faces 9 interconnected.

The sectional views gem. Figs. 7 and 8 show the Connection between the disk pack 5 and the guide pin 2. In the embodiment shown in Fig. 7 shows the guide pin 2 a guide shaft 15 and a bolt head 16, which has a larger diameter than the guide shaft 15. For receiving the bolt head 16 is the disk set 5 is provided with a bore 17 through which the bolt head 16 is passed. The connection between the disk pack 5 and the bolt head 16 is performed by a solder joint, which will be described in more detail below becomes.

As can be seen from FIG. 7, the bolt head 16 is dimensioned that he turned away at least on the leadership shaft 15 Side of the plane of the overhead cover plate 3 surmounted. The projection of the bolt head 16 over the plane of the cover plate 3 can on the one hand as a contact surface for a bolt-shaped Serve transmission element.

Of importance is the level of the cover plate 3 outstanding Part of the bolt head 16 also for the connection of the anchor plate 1 with the guide pin. This is the supernatant the bolt head 16 provided with a chamfer 18, on the after the passage of the bolt head 16 through the hole 17 in the anchor plate a Lot 19, for example in the form of a Ringes is hung up. The solder is based on copper. After applying the solder 19, the entire anchor on heated to a temperature above the melting temperature of the Lotes 19 is located, so that when melting the liquid solder in the contact area between the bolt head on the one hand and the Wall of the bore 17 on the other hand shoots. Subsequently the armature can be cooled down and the guide bolt hardened. For this purpose, the anchor is at least once on the annealing temperature heated for the steel material of the guide pin 2 and for a predetermined time at this temperature kept and then completely cooled. This makes it possible from two components with different material properties existing anchor, namely once a reimbursable Steel material for the guide pin and a soft magnetic iron material for the anchor, firmly together connect, wherein after soldering the steel material can be remunerated to the desired quality. in this connection is taken advantage of the fact that the melting temperature for such highly stressed compounds into consideration coming solders significantly over the hardness and tempering temperature lie for a heat treatable steel material, so that after completion the soldering process, d. H. after firing and freezing of the solder in the connection area between bolt head 16 and the wall of the bore 17 another heat treatment can be performed without thereby soldering is affected in their strength.

The embodiment acc. Fig. 8 shows a modification in that that the bolt head 16 on its cylindrical peripheral surface is provided with a circumferential groove 20. to Connection of the guide pin 2 with the anchor plate 1 is introduced into the groove 20 solder and then the bolt head 16 in the bore 17 of the anchor plate 1 is inserted. Subsequently again the heat treatment described above.

Because the inner wall of the bore 17 due to the lamellar structure of the disk pack is not smooth surface but practically provided with narrow gaps over the entire circumference is, it may be appropriate to both a chamfer 18 as well as to provide a groove 20 and solder in both areas to apply so as to the required for the connection Lot quantity in the entire contact area between bolt head 16 and the wall of the bore 17 to bring.

The laminations 6 and the cover plates 3, 4 are expediently from a sheet with a sheet thickness of for example 0.35 mm. The entire thickness of the anchor plate is for example 4.5 mm.

Fig. 10 shows the application of the punched package at a Yoke body of an electromagnetic actuator. The illustrated electromagnetic actuator is formed substantially by two electromagnets 22 and 23, by two housing parts 24.1 and 24.2 are enclosed, which in turn via a trained as a spacer housing part 24.3 in Spaced apart and with their pole faces 25 against each other are aligned. In the from the spacer 24.3 enclosed movement space between the two pole faces 25th An anchor 26 is arranged, which via a guide pin. 2 in a guide 27 is guided back and forth movable. In which illustrated embodiment, the armature 26 a rectangular basic shape. His anchor plate 1 is for example in a conventional way of soft magnetic iron material produced. The anchor plate 1 can also be laminated be formed, as with reference to FIGS. 1 to 9 above is described.

The armature 26 is connected via a guide pin 28 with a Return spring 8 in conjunction. The other, lower free End 30 of the guide pin 2 relies on a Actuator, for example, the free end of the shaft 31st a gas exchange valve, which in this case only indicated cooled cylinder head 32 of a reciprocating internal combustion engine out is. By a return spring 33, the gas exchange valve acted upon in the closing direction, wherein the return spring 33 and the return spring 29 in their direction of force against each other are directed so that when energized set Electromagnet the anchor plate 1 according to their rest position between the two pole faces 25 of the two electromagnets 22 and 23 occupies, as shown in Fig. 10 is. The housing parts 24.1, 24.2 and 24.3 are connected via connecting means, For example, the indicated clamping screws 34, firmly together to a full housing and over a Contact surface 36 is connected to the cylinder head 32.

As can be seen from Fig. 10, the two electromagnets 22 and 23 each have a cuboid yoke body 37, composed of a variety of thin laminations 37.1 is. The yoke body 37 is in each case two parallel groove-shaped recesses 40 (see Fig. 11), in the one formed as a rectangular ring coil 39 with two parallel Thighs is inserted. The laminations of the yoke body 37 are perpendicular to the plane of the drawing and are firmly connected. Preferably, the compound of Sheet metal laminations through a stamped package, as well as for the preparation of the anchor plate 1 described above and in Fig. 10 in partial section of the yoke body 37 of the electromagnet 23 and in Fig. 11 in a plan view of a blade is shown.

The yoke body 37 of both electromagnets are each of the Housing parts 24.1 and 24.2 of a non-magnetic Material enclosed and indeed, as shown in Fig. 1, in such a way that in the cuboid basic shape of the yoke body 37 in each case the end faces, which comprises of the coil 39 are completely embedded, including the coil 39 are, with their two long sides, however, protrude laterally. The side surfaces of the yoke body 37 can be free lie. The materials are preferably pourable or sprayable materials, such as temperature-resistant Plastics, aluminum, also aluminum compositions, which reduce eddy current formation. The transfusion or overmolding is not the same when punching packages avoiding small dimensional tolerances and causes a solid Connection between yoke body and associated housing part, the dimensional accuracy of the outer dimensions guaranteed remains. The same advantage is achieved when the yoke body is glued into a housing.

FIG. 11 shows a plan view in the direction of the arrow B in FIG. 10 on a lamination 37.1 of the yoke body 37 of the two Elekromagneten 22 or 23. The supervision can be exemplary recognize the position of the impressions 6.1. It is obvious that in the loaded by the impact of the armature 26, the pole faces 25 adjacent area and in the the back 41 of the yoke body 37 forming area over the Indentations the adjacent laminations opposite a force in the direction of arrow 42 stiffened are.

Claims (9)

1. An electromagnetic actuator for actuating a control member, comprising at least one electromagnet formed by a yoke element (37) having a pole face and with a coil, and an armature element which has an armature plate (1) and which can be moved back and forth via a guide pin relative to the pole face, which plate is fixedly connected to the guide pin (2) and has two cover plates (3, 4) between which a laminated stack (5) consisting of a plurality of fixedly interconnected laminations (6) is arranged, which laminations are oriented at right-angles to the cover plates (3, 4) and are joined thereto.
2. An actuator according to Claim 1, characterised in that the cover plates (3, 4) are provided on at least one edge with an angled section (7, 8) which covers the associated end face (9) of the laminated stack (5).
3. An actuator according to Claim 1 or 2, characterised in that the laminated stack (5), at least on the edges extending transversely to the orientation of the laminations, is welded to the cover plates (3, 4).
4. An actuator according to one of Claims 1 to 3, characterised in that the individual laminations (6) have embossed areas which in each case form a cup-shaped recess (6.3) on one side of a lamination and a nipple-shaped raised area (6.2) on the other side of a lamination, and that the raised areas (6.2) of a lamination (6) engage in the recess (6.3) of the adjacent lamination (6) and the laminations (6) are joined together with a positive lock by pressing to form a laminated stack.
5. An actuator according to one of Claims 1 to 4, characterised in that the laminations (6) of the laminated stack (5) are joined securely together by at least two transversely-extending pins (10).
6. An actuator according to one of Claims 1 to 5, characterised in that the guide pin (2) has a guide shaft (15) and a pin head (16) of larger diameter and that the pin head (16) is passed through a bore (17) in the armature plate (1) and is soldered in the region of contact with the armature plate (1).
7. An actuator according to one of Claims 1 to 6, characterised in that the pin head (16) has at least one turned area (20) for receiving a solder.
8. An actuator according to one of Claims 1 to 7, with a yoke body (37) which consists of a plurality of laminations (37.1) which are each provided with a plurality of embossed areas (6.1) which form nipple-shaped raised areas (6.2) on one face of a lamination and correspondingly cup-shaped recesses (6.3) on the other face of a lamination, the raised areas (6.2) in each case of a lamination (37.1) engaging in the recesses (6.3) in the adjacent lamination (37.1) and the laminations (6) being joined securely together with a positive lock by pressing to form a laminated stack, the yoke body (37) being surrounded by a housing (24) on partial regions of its surface.
9. An actuator according to one of Claims 1 to 8, characterised in that the housing (24) is joined to the yoke body (37) by embedding.

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