EP1050890A2 - Electromagnet with a stack of laminations - Google Patents

Abstract

The electromagnet includes a housing (4) accommodating a laminated armature (1) comprising a stack of laminations (3) and a winding. The laminated armature is molded in the housing and comprises undercuts (5) filled with housing casting material. Each the laminations may have similarly located undercuts. The undercuts may be formed as open sectors (5a) in the edge regions of th laminations, or as holes in projections from the edge regions of the laminations. A binding layer may be applied before molding.

Description

The invention relates to an electromagnet, in particular for an electromagnetic one Actuator for actuating a gas exchange valve one Internal combustion engine, with a laminated core, which consists of a variety of stacked sheet metal laminations is built, carries a coil and in a housing is arranged. In addition to e.g. DE 196 46 937 A1 (with regard to an electromagnetic actuator) referred to DE 36 37 411 A1 or DE 37 04 579 A1, both of which Relate to the construction of laminated cores for electromagnets.

Laminated cores for electric motors, transformers or generally for electromagnets, the stacked and punched packages, i.e. through joint partial deformation, form-fitting with each other connected sheet metal lamellas are common prior art. For special applications, such as in electromagnetic actuators (in particular for actuating internal combustion engine gas exchange valves) extremely high strength requirements are placed on them conventional connection technology cannot suffice. The same applies to a connection of the sheet metal lamellas to each other by gluing. According to another possible connection technology, the sheet metal fins can can be pinned together, but this will create the desired magnetic field the sheet metal fins can be disturbed or pinned disadvantageously short-circuited. A similar problem arises in remaining the type of arrangement of the laminated core in the electromagnet housing.

The object of the present invention is to provide a remedial measure for the problems described.
The solution to this problem is characterized in that the laminated core is cast into the housing and has undercuts filled by the housing casting material. Advantageous training and further education are included in the subclaims.

According to the invention, two functions are thus achieved by a single measure fulfilled, namely the individual sheet metal lamellae securely and firmly to Biechpaket held together and the latter fixed in the housing, if this laminated core in the housing in connection with the casting Manufacturing the same is poured. Preferably comes as a material for the housing, i.e. as housing casting material, a light metal alloy (such as AlSi) are used, so the sheet metal parts then surrounding and this holding together this casting material the sheet metal lamellae advantageously not (or at most minimally) electrically connected in a conductive manner, since this casting material is known forms an oxide skin on contact with the air (i.e. on its surface), which acts as an electrical insulation layer. Adverse effects on the Magnetic field build-up is therefore not possible due to this connection technology fear.

In contrast, the individual sheet metal fins are optimally both in Relation to each other and in their entirety as a laminated core in the Electromagnet-receiving housing held when in the laminated core suitable undercuts are provided, which when pouring the same in the housing can be filled with the housing casting material. It can each of the sheet metal plates of the sheet metal package, in particular, arranged identically Have undercuts or only some of the sheet metal fins can possibly be in Interact with other sheet metal lamellas, whereby otherwise in the latter case, the sheet metal fins otherwise should be at least partially connected to one another, for example by the well-known punch packaging. These are in the manufacturing process of the laminated core not only together the stacked laminations punched out, but also partially deformed together in such a way that a positive connection effective at least in a certain direction arises.

As for the formation of the undercuts mentioned, they can be designed in a variety of ways. It is essential that by filling these undercuts with the housing casting material, the laminated core is both sufficiently held together and connected to the housing. In other words, the solidified casting material that fills the undercuts, alone or in cooperation with another, but relatively simple connection technology (such as, for example, the punching package), prevents any relative movement of the individual sheet metal lamellae to one another and any movement of the sheet metal package in the housing.
Various possible configurations of the said undercuts are shown in the attached schematic diagrams, which are explained in more detail later as preferred exemplary embodiments of the invention.

First, however, an advantageous further development of the present Invention described, according to which the laminated core before casting with a Connection layer is provided when pouring into the housing the housing casting material forms a material bond. In order to then there is not only a purely positive connection, but an additional one integral bond between the laminated core and the housing before, this additional composite over the surface of the laminated core considered partially or collectively can be provided, and the always reinforced or supported the fixation of the sheet metal package in the housing.

To produce such an (additional) integral bond can the laminated core, for example, by thermal spraying, by galvanizing, by brushing or the like coated with the named connection layer are melted during the subsequent casting process becomes. Suitable metals or Fluxing agents are used that form an intermetallic Phase between the housing casting material (in particular a light metal alloy) and favor the laminated core material (preferably pure iron).

Such a direct coating of the sheet metal package with said However, the connection layer only makes sense if the creation of electrical losses in the laminated core is negligible, because after all with the integral bond, an intermetallic is formed at the same time and thus electrically conductive phase between the housing casting material and the laminated core material. But should such electrical Losses should be avoided between the sheet metal fins and an electrical insulation layer is provided for said connection layer his.

For this purpose, the laminated core is coated with the connection layer before coating with a suitable electrical insulation layer, for example magnesium oxide, coated to all the advantages of the positive connection to be able to use without an electrical short between the sheet metal fins is brought about. To additionally the already mentioned material connection bring about when pouring the sheet metal package into the housing, for example. by PVD coating (powder vapor coating) first the insulation layer applied and then the preferably metallic compound layer. This metallic connection layer can be applied otherwise by immersing the laminated cores in a liquid Al alloy, for example until the intermetallic compound forms. Im a subsequent one The step is then encased in the laminated core Cast housing, which creates the cohesive connection.

Fig.1a

die Vorderansicht eines erfindungsgemäß in ein Gehäuse eingegossenen Blechpaketes,

Fig.1b

die zur Anordnung nach Fig.1a zugehörige Seitenansicht,

Fig2a, Fig.2b

zwei einander ähnliche Abwandlungen vom Ausführungsbeispiel nach Fig.1a (in gleicher Ansicht), wobei hier sowie in den folgenden Figuren die einzelnen Blechlamellen des Blechpaketes vereinfacht, d.h. ohne Aussparung für die Magnet-Spule, dargestellt sind,

Fig.3a

eine weitere Abwandlung vom Ausführungsbeispiel nach Fig.1a (in gleicher Ansicht),

Fig.3b

eine Abwandlung des Ausführungsbeispieles nach Fig.3a unter perspektivischer Darstellung des Blechpaketes.

Returning to the undercuts which ensure the essential positive connection, several exemplary embodiments will now be described with reference to the attached figure representations. In all figure representations, each of which shows a sheet stack according to the invention in a highly simplified manner, the same elements are provided with the same reference numbers. In detail shows

Fig.1a

the front view of a laminated core cast according to the invention in a housing,

Fig.1b

the side view associated with the arrangement according to FIG. 1a ,

Fig2a, Fig.2b

two mutually similar modifications of the exemplary embodiment according to FIG. 1a (in the same view), the individual sheet-metal lamellae of the sheet-metal stack being shown here and in the following figures in a simplified manner, ie without a cutout for the magnet coil,

Fig.3a

a further modification of the exemplary embodiment according to FIG. 1a (in the same view),

Fig.3b

a modification of the embodiment of Figure 3a with a perspective view of the laminated core .

Fig.4a

als Vorderansicht (wie Ansicht in Fig.1a), sowie

Fig.4b

als Seitenansicht (wie Ansicht in Fig.1b), und die

Fig.5a, Fig.5b

als Abwandlungen des Beispieles nach den Fig.4a, 4b in gleicher Darstellung.

A further modification of the laminated core, in which only some of the laminations in cooperation with others form the mentioned undercuts

Fig.4a

as a front view (as view in Fig.1a ), and

Fig. 4b

as a side view (as view in Fig.1b ), and the

Fig.5a, Fig.5b

as modifications of the example according to Figures 4a, 4b in the same representation.

Fig.6

die Seitenansicht (wie Ansicht in Fig.1b) eines weiteren Ausführungsbeispieles eines erfindungsgemäß in ein hier nicht dargestelltes Gehäuse eingegossenen Blechpaketes.

Finally shows

Fig. 6

the side view (as view in Fig.1b ) of a further embodiment of a laminated core cast according to the invention in a housing, not shown here.

Reference number 1 denotes a laminated core of an electromagnet, which can be installed, for example, in an electromagnetic actuator; alternatively, this laminated core 1 can also be part of a transformer or an electric motor. The laminated core 1 accordingly carries a coil (magnet coil), ie a winding of electrically conductive wire, which is not shown here for the sake of simplicity (and since it has no relation to the invention). In Fig.1a two recesses 2 can be seen in the laminated core 1, in which this (magnetic) coil with its two (here longer) legs is or can be inserted. Also for the sake of simplicity, these recesses 2 are not shown in the further exemplary embodiments or figure representations, but of course are also present there.

The laminated core 1 is constructed from a multiplicity of laminated laminations 3 stacked on one another, as shown in FIGS. 1b, 3b, 4b, 5b and 6 . These sheet metal lamellae 3 can be connected to one another as usual by die-cut packaging, ie, by means of such a die-cut packetization, the sheet metal lamellae 3 are basically held together to form the sheet metal packet 1, although this cohesion can only withstand relatively low forces.

The essential cohesion between the laminations 3 of the laminated core 1 is produced in that this laminated core 1 is cast into a housing 4 which accommodates the electromagnet (and thus the laminated core 1 with the said coil). A fraction of this housing 4 is (only) shown in Figures 1a, 1b . Here, as can be seen, the housing 4 has a cuboid shape and accommodates the laminated core 1 between its base plate 4a (which is at the top in FIGS. 1a , 1b ) and the (four) side walls 4b, 4c. The laminated core 1 is held in a form-fitting manner in the housing 4 or on its base plate 4a and in the exemplary embodiment according to FIGS. 1a, 1b on the opposite side walls 4b, by so-called undercuts 5. These undercuts 5 are for this purpose with the housing -Gussmaterial filled so that these undercuts 5 at the same time the individual laminations 3 are held together to the laminated core 1.

As just mentioned, the laminated core 1 is cast into the housing 4. This housing 4 is thus produced in a casting process, preferably using a light metal alloy as the casting material. At this manufacturing or casting process of the housing 4 is simultaneously the Sheet package 1 integrated and thus cast in, the housing casting material in the undercuts 5, which are in the laminated core 1 (or in the individual Sheet metal fins 3 of the same) are provided, penetrates and this Filled undercuts 5. With the solidification of the casting material is then not only the laminated core 1 securely in the housing 4 or on its base plate 4a (as well as on the side walls 4b, 4c), but at the same time there are also the sheet metal plates 3 securely fixed relative to each other.

In the exemplary embodiment according to FIG. 1a , the undercuts 5 are designed as breakthrough sectors 5a introduced into the edge region of the sheet-metal fins 3. Each of the laminations 3 of the laminated core 1 has undercuts 5 of the same shape and arrangement, so that the breakthrough sectors 5a of the individual laminations 3 in the illustration according to FIG . In each case, a first undercut 5 (or breakthrough sector 5a) faces the base plate 4a of the housing 4 and a further undercut 5 each faces the two opposite side walls 4b, against which all the sheet metal fins 3 rest with their side edges.

The undercuts 5 formed in this way are referred to as the breakthrough sector 5a because they essentially resemble a sector of a circular breakthrough, for example, the angle of the selected sector being, however, so large that an undercut actually occurs. Only the undercut 5 (or breakthrough sector 5a) facing the base plate 4a should therefore, due to its filling with the cast material of the housing 4, prevent the entire laminated core 1 or each individual laminated plate 3 from moving away from the base plate 4a (down here) to move away. Such an undercut 5 in the form of the breakthrough sector 5a can also be shaped differently than shown, for example similar to the projection 5b of the exemplary embodiment according to FIG. 2b which will be explained later, but in a form reflected in the surface of the sheet metal lamella 3.

In the exemplary embodiments according to FIGS. 2a, 2b , the undercuts 5 are formed by projections 5b protruding from the edge region of the sheet metal laminations 3, with each of the sheet metal laminations 3 of the laminated core 1 again having an identically shaped and arranged projection 5b, which is the base plate 4a of the housing 4 (not shown here for the sake of simplicity). Each of these projections 5b protrudes through the casting of the laminated core 1 into the housing 4, as it were, into its base plate 4a and thus anchors the associated laminated plate 3 and the entire laminated core 1 securely in the housing 4. Essentially, these projections 5b are dovetail-shaped, the through the undercut 5 indicated by the arrow to the reference number 5 can be seen particularly clearly, ie the housing casting material penetrates into this area indicated by the arrow and then fixes each individual sheet metal lamella 3 on the base plate 4a when it solidifies. Because of the relatively large area or the large circumference of this undercut 5, a single projection 5b of this type is sufficient for each sheet metal lamella 3, but of course such projections 5b can also be provided on the edges of the sheet metal lamellae 3 facing the side walls 4b.

In the exemplary embodiments according to FIGS. 3a, 3b , too, the undercuts 5 are formed by projections 5b protruding from the edge region of the sheet-metal fins 3, which, however, do not have an outer contour forming an undercut here, but rather are each provided with an opening 5c. The housing casting material penetrates into these (for example circular) openings 5c when the laminated core 1 is poured into the housing 4 to be formed in the casting process, so that these openings 5c form the undercuts 5 mentioned and again each sheet metal plate 3 is optimally fixed to the housing 4 becomes.

In the embodiment of Figure 3a, the apertures 5c (or the projections 5b) which are again in each of the plate fins 3 of the laminated core 1 is formed the same and arranged in the same thereto protrude in the opposite side walls 4b of the casing 4 into (see Fig. .1a ). In the exemplary embodiment according to FIG . 3b - (here the laminated core 1 is shown in perspective in an exploded view ) - on the other hand, the openings 5c or the projections 5b in each of the laminations 3 of the laminated core 1 are shaped the same way, but with respect to the respectively adjacent laminations 3 on the same edge, but offset. This results in a particularly stable hold. In this case, two projections 5b, each provided with an opening 5c, protrude into the base plate 4a of the housing 4 (see FIG . 1a ).

In the exemplary embodiments according to FIGS . 4a to 5b , only some of the sheet metal plates 3, in cooperation with other sheet metal plates 3, form the undercuts 5 mentioned, these undercuts 5 again being formed by projections 5b projecting from the edge region of the sheet metal plates 3, which protrusions at least partially outside the plane of FIG respective sheet metal lamella 3. The undercuts 5 formed by these projections 5b can be clearly seen from FIGS. 4b, 5b or are again identified by arrows. Via these undercuts 5 identified in this way, at least the sheet-metal fins 3 provided with these projections 5b are thus securely anchored in the base plate 4a when poured into the housing 4. The sheet metal lamellae 3 not provided with projections 5b (or undercuts 5) are otherwise connected to the sheet metal lamellae 3 fixed in this way, in particular by means of a stamping package which is customary in the case of such sheet metal packs.

The exemplary embodiment according to FIG. 6 is slightly similar to that according to FIG. 5b , but here again each sheet metal lamella 3 has an undercut 5 which arises in cooperation with the adjacent sheet metal lamellae 3 and is each formed by a projection 5b which is at least partially outside the plane the plate lamella 3 lies. These projections 5b are corrugated parallel to each other and form an undercut 5 between each of them, which is filled with the casting material of the housing 4, that is to say these projections 5b each lie after the casting of the laminated core 1 in the housing 4, almost like an anchor, preferably in the base plate 4a.

Of course, other embodiments are possible as well can quite a lot of details, especially of a constructive nature deviate from the exemplary embodiments shown, without to leave the content of the claims.

Claims (10)

Electromagnet, in particular, for an electromagnetic actuator for actuating a gas exchange stroke valve of an internal combustion engine, with a laminated core (1) which is made up of a plurality of stacked laminations (3), carries a coil and is arranged in a housing (4) ,
characterized in that the laminated core (1) is cast into the housing (4) and has undercuts (5) filled in by the housing casting material. Electromagnet according to claim 1,
characterized in that each of the laminations (3) of the laminated core (1) has in particular identically arranged undercuts (5). Electromagnet according to claim 1,
characterized in that only some of the sheet metal lamellae (3) form undercuts (5), possibly in cooperation with other sheet metal lamellae (3), the sheet metal lamellae (3) being otherwise otherwise connected to one another, in particular by punching packaging. Electromagnet according to one of the preceding claims,
characterized in that the undercuts (5) are designed as breakthrough sectors (5a) introduced into the edge region of the sheet metal lamellae (3). Electromagnet according to one of the preceding claims,
characterized in that the undercuts (5) are formed by projections (5b) protruding from the edge region of the sheet metal laminations (3). Electromagnet according to claim 5,
characterized in that the projections (5b) are substantially dovetail-shaped in the plane of each sheet metal lamella (3). Electromagnet according to claim 5,
characterized in that the projections (5) are at least partially outside the plane of the respective sheet metal lamella (3). Electromagnet according to one of the preceding claims,
characterized in that the projections (5b) are provided with openings (5c). Electromagnet according to one of the preceding claims,
characterized in that the laminated core (1) is provided with a connecting layer before pouring, which forms a material bond with the cast housing material when poured into the housing (4). Electromagnet according to claim 9,
characterized in that an electrical insulation layer is provided between the sheet metal fins (3) and the connecting layer.

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