EP0033699A2 - Method and device for assembling a magnetic circuit by using an adhesive - Google Patents

Abstract

1. A process for assembling by glueing a magnetic circuit resulting from the stacking of metal plates and comprising, suitably individualised, at least two cores (11A, 11B) which are parallel to each other, and at least one yoke (12) for connecting said cores at one at least of their ends, the process being of the kind wherein glue (17) is disposed between the surfaces which are to be brought together of said yoke (12) and said cores (11A, 11B), and a clamping pressure which is suited to the desired glueing effect is applied thereto in a direction which is perpendicular to said surfaces and therefore parallel to the plane of the metal plates (15, 16) in question, the metal plates (15, 16) making up the cores (11A, 11B) and the yoke (12) being left free of any means for fixing them together before the glueing operation to be carried out, characterised in that, in said glueing operation, prior to the clamping pressure (F) and in a direction perpendicular to the plane of said metal plates (15, 16), a moderate holding pressure (P) is applied thereto, to prevent them from riding over each other in the clamping operation while permitting relative displacement thereof parallel to themselves, in such a way as to prevent, as a corollary, glue from penetrating between the metal plates.

Description

The present invention relates generally to electrical equipment comprising a magnetic circuit _o

This is the case, mainly, of transformers; but it can also be simple selfso

To limit the eddy current losses, the magnetic circuit of a transformer is usually a sheet circuit, that is to say a circuit resulting from the stacking of sheets.

Such a magnetic circuit comprises in practice at least two parallel cores or legs, on each of which is engaged a coil, and which, for the continuity of the magnetic circuit, are connected to each other by a yoke at each of their endso

One of the problems to be solved in the realization of the transformers is therefore to ensure the establishment on these cores of the corresponding windings even though they are cores to be connected continuously by yokes.

For low power transformers, for example less than 4 KVA, it is customary to produce the magnetic circuit by cutting in the form of U or E, depending on the number of phases, the sheets to be used, by stacking these sheets, by putting the corresponding windings on the cores formed by the legs thereof, and by then connecting these legs by a cylinder head.

In other words, according to this technique, the nuclei of the magnetic circuit are from the outset in one piece with yokes at one of their ends and are therefore not each individually identified.

But for processors of supérieu- e _r power than indicated above, this technique is not applicable practice, because of that non-recoverable metal losses due to cuts U or E are too important to be acceptable economically

For transformers of a certain power, the solution to limit the losses in metal usually consists in ensuring individually the cutting of the sheets necessary for the constitution of the cores on the one hand, and the cylinder heads on the other hand

Cylinder heads and cores therefore being thus individualized, the problem is to ensure a good junction within the magnetic circuit which they are responsible for constituting, after fitting the corresponding windings.

Several solutions are proposed for this purpose.

The first consists in operating by systematic entanglement of the sheets constituting the cores and cylinder heads, this entanglement being obtained for example by a systematic alternation, from one layer to another, of the sheets used, during the stacking of these. this.

Such a process is particularly long and expensive to carry out; for example, for a ₁₆ KVA transformer, it takes in practice more than an hour to stack the sheets constituting the magnetic circuit, put the corresponding windings on the cores thus formed, and close these cores by cylinder heads.

In addition, due to the inevitable variations in thickness from one sheet to another due to the rolling tolerances thereof, the closing of the circuit by cylinder heads, which requires inserting one by one the constituent sheets d such a cylinder head between the corresponding plates of the cores which it must connect, frequently raises difficulties your.

Finally, for a three-phase transformer, such a tangle process requires in practice the cutting of three different types of sheets to be stacked.

A second solution, for closing the magnetic circuit of a transformer, consists in operating by welding: cores and yokes are each individually assembled isolémer, then, after installation of the corresponding windings, they are joined two by two by welding.

For a three-phase transformer, such a process advantageously makes it possible to be satisfied with only two different types of sheets.

However, when these sheets are oriented crystals, the welding which is thus applied to them takes place at the expense of their magnetic quality so that the benefit normally due to the use of such sheets is then lost.

A third solution already known for assembling the magnetic circuit of a transformer consists in operating mechanically: cores and cylinder heads are assembled in isolation, by bonding their constituent sheets, transversely to the plane of these, then assembling them two to two is done mechanically using threaded tie rods.

Such an assembly process has various drawbacks.

First, the cores and yokes each individually forming packets in which the sheets corre- p _o ndantes are all integral with each other, it is necessary for a connection between them such packets, to rectify by machining the surfaces to be faced, and the corresponding rectification operation is relatively costly

In addition, for the passage of the threaded tie rods to be used, it is necessary to provide, on the edge of the cores and cylinder heads to be assembled, grooves, and, in practice, these are obtained by differentiating the width of the sheets. implemented, so that, for a polyphase transformer, four different types of sheets are necessary.

The present invention generally to ob- j _e t a joining process by sticking a magnetic circuit to avoid the above drawbacks.

More specifically, it relates to a process specific to such an assembly by gluing, a device specific to the implementation of this process, the magnetic circuit obtained, and electrical equipment, in particular transformer, comprising such a magnetic circuit. .

The method according to the invention, which thus relates to the as- _s emblage by bonding a magnetic circuit resulting from the lamination stack and comprising, suitably individualized, at least two parallel cores to one another and at least one cylinder head suitable for connecting said cores to at least one of their ends, and which is of the type according to which, in the usual way in terms of bonding, there is glue between the surfaces to be faced of said cylinder head and said cores and there is applied to these, in a direct _io n perpendicular to said surfaces and therefore parallel to the plane of the sheets concerned, a clamping pressure specific to the desired bonding, the sheets constituting the cores and the cylinder head being left free of any connection between they before bonding to be performed, is characterized in that, when this adhesive is applied to these sheets, before the clamping pressure, and a direction perpendiculai- _r e to their plane, a moderate pressure may ntien to avoid overlapping during tightening while allowing a relative movement parallel to themselves.

In other words, according to the invention prior to bonding of the cores and yokes together, the constituent plates of the cores and yokes are simply stacked without further lidarisation _so on as provided if necessary, to allow manipulation by any link, such as tape looped around them overall.

In fact, their relative positioning can then only be approximate, their correct positioning being ensured subsequently by the clamping pressure used, which therefore, according to the invention, before the bonding to be ensured, causes if necessary a sliding relative, the relative to each other, of the various sheets concerned, so as to bring them into the suitable position for proper execution of this bonding.

The holding pressure implemented jointly according to the invention prevents such a clamping pressure from leading, by relative overlap, to untimely interpenetration of the sheets constituting a core, for example with the sheets constituting the cylinder head with which it must be assembled.

Thanks to such a process, the bonding of the sheets constituting a core or of a cylinder head is avoided beforehand, and therefore their subsequent rectification is also avoided.

The process according to the invention also makes it possible to considerably reduce the assembly times; for a 16 KVA transformer for example, this assembly time can be reduced to around a quarter of an hour.

Finally, the process according to the invention is easily satisfied with an easy and inexpensive adaptation to different stacking thicknesses for the cores and cylinder heads to be assembled, which, being transformers, makes it possible to advantageously cover a wide range power with a minimum of different types of circuits; in particular, the cross circuits of Saint-André can advantageously be avoided.

Admittedly, provision is made, in the US patent N ° 3,222,626, to ensure by bonding the assembly of the cores and yokes of a magnetic circuit, but by a process which, ensuring a strapping by rings of the ends of said cores and cylinder heads, is different from that which is the subject of the present application: no relative movement of the sheets concerned is expected, and glue is inserted between these sheets.

Likewise, if, in the US patent No. 2,467,218, which, of surcroft, is not aimed at such bonding, but the overmolding of metal caps at the ends of the cores and cylinder heads, provision is made for applying two orthogonal pressures to the sheets concerned, one perpendicular to their confrontation surfaces, the other perpendicular to their plane, any relative movement of these sheets is excluded.

• la figure 1 est une vue en perspective d'un transformateur réalisé suivant l'invention ;
• la figure 2 est une vue en plan, suivant la flèche II de la figure 1, du seul circuit magnétique du transformateur représenté sur cette figure 1 ;
• la figure 3 est, à échelle supérieure, une vue en coupe transversale partielle de ce circuit magnétique, suivant la ligne III-III de la figure 2 ;
• la figure 4 est une vue en perspective d'un dispositif propre à l'assemblage par collage d'un tel circuit magnétique, avec des arrachements locaux ;
• la figure 5 est une vue analogue à la figure 3 et illustre une phase préparatoire au collage à assurer ;
• les figures 6A et 6B sont des vues analogues à celle de la figure 4 et illustrent deux phases successives de mise en oeuvre du dispositif suivant l'invention ;
• la figure 7 est une vue partielle en coupe transversale de ce dispositif, suivant la ligne VII-VII de la figure 6 ;
• la figure 8 est une vue analogue à celle de la figure 2 pour un autre type de transformateur ;
• les figures 9 et 10 sont des vues analogues à celles des figures 2 et 8, pour de simples selfs ;
• la figure 11 est une vue analogue à celle de la figure ₈ pour une autre configuration du circuit magnétique concerné ;
• la figure 12 est une vue latérale du circuit magnétique représenté à la figure 11, suivant la ligne XII-XII de cette figure 11 ;
• les figures 13 et 14 sont des vues respectivement analogues à celles des figures 11, 12, pour une autre configuration du circuit magnétique concerné ;
• la figure 15 est une vue analogue à celle de la figure 13, pour une autre configuration du circuit magnétique concerné ;
• la figure 16 est une vue en plan, suivant la ligne XVI-XVI de la figure 18, d'un circuit magnétique à noyaux et culasses enchevêtrés auxquels s'applique le procédé suivant l'invention;
• les figures 17 et 18 sont des vues latérales de ce circuit magnétique, suivant respectivement les lignes XVII-XVII et XVIII-XVIII de la figure 16 ;
• la figure 19 en est une vue en plan prise suivant la ligne XIX-XIX de la figure 18 ;
• la figure 20 en est une autre vue latérale, suivant la ligne XX-XX de la figure 16 ;
• les figures 21 à 25 sont des vues respectivement analogues à celles des figures 16 à 20, pour un enchevêtrement suivant l'invention des noyaux et culasses mis en oeuvre ;
• les figures 26, 27 et 28 sont des vues en plan d'autres circuits magnétiques auxquels peut s'appliquer le procédé suivant l'invention ;
• la figure 29 est une vue en perspective d'une joue susceptible d'être mise en oeuvre dans un tel circuit magnétique ;
• la figure 30 est une vue partielle en plan d'un circuit magnétique dans lequel de telles joues sont mises en oeuvre ;
• les figures 31 et 32 sont des vues analogues à celle de la figure 11 et concernent d'autres configurations possibles pour le circuit magnétique auquel peut s'appliquer le procédé suivant l'invention.

The characteristics and advantages of the invention will become apparent from the description which follows, by way of example, with reference to the appended schematic drawings in which:

• Figure 1 is a perspective view of a transformer produced according to the invention;
• Figure 2 is a plan view, along arrow II of Figure 1, of the single magnetic circuit of the transformer shown in this Figure 1;
• Figure 3 is, on a larger scale, a partial cross-sectional view of this magnetic circuit, along line III-III of Figure 2;
• Figure 4 is a perspective view of a device suitable for assembly by bonding of such a magnetic circuit, with local cutaway;
• Figure 5 is a view similar to Figure 3 and illustrates a preparatory phase for bonding to be provided;
• Figures 6A and 6B are views similar to that of Figure 4 and illustrate two successive phases of implementation of the device according to the invention;
• Figure 7 is a partial cross-sectional view of this device, along the line VII-VII of Figure 6;
• Figure 8 is a view similar to that of Figure 2 for another type of transformer;
• Figures 9 and 10 are views similar to those of Figures 2 and 8, for simple inductors;
• Figure 11 is a view similar to that of Figure ₈ for another configuration of the magnetic circuit concerned;
• Figure 12 is a side view of the magnetic circuit shown in Figure 11, along the line XII-XII of this Figure 11;
• Figures 13 and 14 are views respectively similar to those of Figures 11, 12, for another configuration of the magnetic circuit concerned;
• Figure 15 is a view similar to that of Figure 13, for another configuration of the magnetic circuit concerned;
• Figure 16 is a plan view, along line XVI-XVI of Figure 18, of a magnetic circuit with tangled cores and yokes to which the method according to the invention applies;
• Figures 17 and 18 are side views of this magnetic circuit, respectively along the lines XVII-XVII and XVIII-XVIII of Figure 16;
• Figure 19 is a plan view taken along the line XIX-XIX of Figure 18;
• Figure 20 is another side view along the line XX-XX of Figure 16;
• Figures 21 to 25 are views respectively similar to those of Figures 16 to 20, for a tangle according to the invention of the cores and cylinder heads used;
• Figures 26, 27 and 28 are plan views of other magnetic circuits to which the method according to the invention can be applied;
• FIG. 29 is a perspective view of a cheek capable of being used in such a magnetic circuit;
• FIG. 30 is a partial plan view of a magnetic circuit in which such cheeks are used;
• Figures 31 and 32 are views similar to that of Figure 11 and relate to other possible configurations for the magnetic circuit to which the method according to the invention can be applied.

In FIG. 1, a single-phase transformer is recognized, the magnetic circuit 10 of which, shown diagrammatically in FIG. 2, comprises, suitably individualized, two cores or similar legs 11A, 11B, which are parallel to each other, and two similar yokes 12, which connect the cores 11A, 11B to each other at each of their ends, extending between said cores 11A, 11B, the assembly generally having a rectangular outline.

In the example of implementation shown, the cores 11A, 11B and yokes 12 themselves have rectangular contours, and their junctions two by two are straight, along their respective edges.

On the cores 11A, 11B are respectively engaged coils 13A, 13B, the first constituting a primary coil, and the second a secondary coil.

The formation of such coils 13A, 13B is con- _n ue by itself, and not part of the present invention, it is not described in detail here.

In a manner known per se, the cores 11A, 11B each result from the stacking of sheets 15, all rectangular, and, likewise, the cylinder heads 12 each result from the stacking of sheets 16, all rectangular.

According to the invention, and in combination, on the one hand cores 11A, 11B and cylinder heads 12 are joined two by two by gluing, and on the other hand the sheets 15 constituting the cores 11A, 11B are all identical to each other and there is the same for the sheets 16 constituting the cylinder heads 12 ₀

In addition, according to the invention, and apart from at least part of their edges, the sheets 15 constitut _ut ives of the cores 11A and 11B, and the sheets 16 constituting the cylinder heads 12, are devoid of any connection between they transversely in relation to their plans.

In other words, between any two consecutive sheets 15 of a core 11A, 11B, it is possible to pass any sheet or blade, for example a knife blade, and the same is true between any two consecutive sheets 16 of the yokes 12 _o

Thus, in the magnetic circuit 10 according to the invention _t ion, the only existing glue films are adhesive films 17 present at each end of each cylinder head 12, between the surfaces by which cores 12 and yokes 11A, 11B are confronted two by two.

It is, for the cylinder heads 12, the edge of their longitudinal end.

In Figure 3, the adhesive film 17 shown has been deliberately exaggerated, to be better visible; in practice, such a film is much more reduced, as will appear below.

FIG. 4 illustrates by way of example a device specific to the assembly by gluing, according to the invention, of the magnetic circuit 10 of the single-phase transformer described above.

This device comprises a base 20 and, projecting therefrom, two similar receptacles 21, which extend parallel to each other, and which are each respectively suitable for the establishment, by their ends, of cores 11A, 11B, with insertion of the yokes 12, as will appear below.

Each receptacle 21 has an overall L-shaped configuration, it is formed by a horizontal sole 22 and, at one end of the latter, by a vertical stop 23.

Each receptacle 21 are associated with means that clean clamp to exert a clamping pressure on the ensem- _bl e 11A consisting of cores and cylinder head 12 to be assembled.

It is, in the embodiment shown, a cylinder 24, which is disposed at the end of such a receptacle 21 opposite to that along which is the stop 23 which delimits it, and whose piston 25 is movable horizontally, in the direction of this stop 23, and carries a distribution flange 260

Each receptacle 21 is also associated with holding means capable of exerting a holding pressure on the assembly consisting of the cores 11A and the yokes 12 to be assembled, during their bonding.

In the embodiment shown, it is, for each receptacle 21, and in cooperation with the sole 22 thereof, two rotary cylinders 27, which are each respectively arranged at the ends of this receptacle 21, at l 'outside the volume delimited by the two receptacles 21, and whose pistons 28, in addition to their rotary movement, which is a reciprocating quarter-turn movement, are movable vertically.

In the embodiment shown, the piston 28 of each rotary actuator 27 carries at its end a T-shaped cross member 29, and with such a cross member there is associated laterally a fixed stop 30, which is disposed at the end of a pedestal 31 , and which is preferably adjustable in height.

For example, and as shown, such a stop 30 is formed by a screw placed at the end of the corresponding pedestal 31, sheltered from a square 32.

The two rotary cylinders 27 associated with the same récepta- c _l e 21, it is associated a distributor sill 33 removable.

In the embodiment shown, the two distribution beams 33 corresponding to the two receptacles ₂₁ are connected to each other by a common grip handle 34, the assembly forming a distribution yoke 35 ₀

Finally, in the embodiment shown, there is also associated with each receptacle 21 alignment means capable of exerting alignment pressure on the assembly formed by the cores 11A, 11B and the yokes 12 to be bonded.

It is, in the embodiment shown, a cylinder 37 whose piston 38 is movable horizontally, perpendicular to the piston 25 of the cylinders 24, and is thus capable of exerting an alignment pressure on a distribution sill 3 ° movable ascent in the receptacle 21 concerned, between the stop 23 delimiting the latter and the distribution flange 26 carried by the piston 25 of the corresponding jack 24.

The bonding of the magnetic circuit 10 of the single-phase transformer described above can therefore be done in the following manner.

The cores 11A and 11B on the one hand and the cylinder heads 12 on the other hand are firstly produced individually, in a manner known per se, by stacking the corresponding sheets 15 and 16.

To facilitate handling, the packages of sheets thus produced can each be individually bound in bundles by one or more adhesive tapes (not shown in the figures) o

On the cores 11A, 11B thus produced, the corresponding coils 13A, 13B are then put in place.

As is usual, this installation can be done for example, using gutters, carcasses, or other forms of this type,

However, as a variant, according to the invention, it can advantageously be done by direct winding on the cores 11A, 11B, these being placed for this purpose on a winding lathe.

The surfaces to be faced with cores 11A, 11B and cylinder heads 12 are then coated with glue.

It is for example a polymerizable adhesive requiring for its setting an activator.

Preferably in this case, according to the invention, for each core 11A, 11B-cylinder head 12 pair, the adhesive used is applied to any one of the core-cylinder head elements, and the corresponding activator is applied to the other of these.

For example, and as illustrated in FIG. 5, an adhesive film 17 'is applied to the core 11A, while an activator film 17 "is applied to the cylinder head 12.

Thus, after gluing, a satisfactory time is left free for the rest of the operations, while a favorable development of the adhesive is ensured.

Also preferably, the adhesive used comprises a ferrite charge.

The cores 11A, 11B provided with their coils 13A, 13B are then placed by their ends in the receptacles 21, FIG. 6A, with insertion of the yokes 12 between them at said ends.

In practice, and as visible in FIG. 1, shims 40 of thickness are also interposed between each yoke 12 and the coils 13A, 13B, in particular in the case where these are wound directly on the cores 11A, 11B or are wound only on gutters, that is to say on forms devoid of any flange at their ends.

The distribution yoke 35 is placed on the cylinder heads 12 and the ends of the cores 11A, 11B, on either side of the coils 13A, 13B, and the actuation of the jacks 27 and 37 is controlled.

Cylinders 37 may be the first to intervene, but these are preferably 27 ° cylinders

Anyway, the cylinders 27 must intervene before the cylinders 24, and it is the same for the cylinders 37.

It will be assumed below that the jacks 27 are the first to intervene.

Their pistons 28 rotate a quarter of a turn, and start to descend.

At the end of their descent, the T-cross 29 which they carry, which was initially parallel to the receptacles 21, is perpendicular to these and comes to bear on the one hand on the corresponding distribution lcngrine 33, and on the other part on the support stop 30 which is associated with it, FIG. 6B.

This results in the application, on the cylinder heads 12 and the ends of the cores 11A, 11B, of a moderate holding pressure P, in a direction perpendicular to the planes of the sheets constituting these cylinder heads and these cores, as shown schematically by an arrow P in figure 70

From the actuation of the jacks 37 it also results, after the application of the holding pressure P in the implementation example concerned, the application to the cores 11A, 11B and to the cylinder heads 12 of a pressure alignment _F t in a direction parallel to the planes of the sheets constant t _i tutives of these cores and yokes and perpendicular to that in which is subsequently perform, as described hereinafter, the clamping pressure F developed by the actuators ₂₄ , as shown diagrammatically by arrows F ′ and F in FIG. ₄₀

With respect to such alignment pressure F ′, the cores 11A, 11B are buttressed jointly by the corresponding cylinders 37, and the cylinder heads 12 are buttressed by the coils 13A, 13B, by means of the shims 40 thick.

The alignment pressure to be used is moderate.

Indeed, it has for single base to readjust if neces- _s area alignment cylinder head relative to the ends of the cores 11A, 11B, and it has to overcome the corresponding friction, taking into account the holding pressure P when this is applied before the alignment pressure F '.

The actuation of the jacks 24 is then controlled, and, taking into account the stops 23 delimiting at their opposite end the corresponding receptacles 21, this results in the application, to each of the ends of the cores 11A, 11B, for the whole constituted by these cores 11A, 11B and the cylinder heads 12 inserted between them, with an energetic tightening pressure of a nature to cause an intimate approximation, according to their respective confronting surfaces, of said cores 11A, 11B and of said cylinder heads 12, and therefore likely to allow the desired bonding between them.

In practice, this clamping pressure F, which is exerted parallel to the planes of the various sheets concerned, on the edge thereof, along the arrow F in FIG. 7, is made sufficient, taking into account that the components 11A, 11B cores and 12 son cylinder heads. left free from any connection between them before the gluing of these cores and of these cylinder heads, to cause, if necessary, within each core and / or each cylinder head, a relative displacement relative to each other of the corresponding sheets, by sliding of these sheets together, such as to lead, from cores 11A, 11B to cylinder heads 12, to an intimate bringing together, by their edges, of the corresponding sheets opposite.

In other words, for each pair of facing sheets, the adhesive film 17 inserted between them is crushed as much as possible, and therefore minimizes the air gap due to this adhesive film.

The ferrite preferably present in the adhesive used, if necessary, fills the gaps between sheets due to the inevitable cutting tolerances thereof, which improves the continuity of the magnetic circuit concerned, from cores to yokes, and thereby the performances, and in particular the efficiency, of the transformer obtained.

It also turns out that such a presence of ferrite in the adhesive used improves the tensile strength of the latter after being prized.

Given the approximation of the films of adhesive 17 ′ on the one hand and of activator 17 "on the other hand provided by the clamping pressure, the effective setting of the adhesive used begins upon application of this clamping pressure.

At the end of a reduced time, of the order of 6 min for example, it is sufficient for the clamping pressure F to be released, the same being true for the holding pressure P and the alignment pressure F ', and that the transformer thus assembled is then removed from the device in which its assembly by gluing took place according to the invention.

Preferably, the holding pressure P is established in two stages, and therefore passes successively from a lower level Pl to an upper level P2.

Preferably also, the clamping pressure F is released in two stages, and therefore passes successively from an upper level F1 to a lower level F2.

In practice, in this case, the holding pressure is established at its upper level P2 before the clamping pressure is brought back to its lower level F2.

In other words, the cycle of operations, for the pressures concerned, is preferably the following: holding pressure P at its lower level Pl, clamping pressure F at its upper level F1, holding pressure P at its upper level P2, and clamping pressure F at its lower level F2.

At its upper level F1, the clamping pressure F has the task of ensuring the intimate approximation of the sheets to be bonded, as described above.

However, its subsequent reduction to a lower level F2 makes it possible to ensure that, after the intimate bringing together of the sheets, the polymerization of the adhesive advantageously takes place under reduced pressure, which prevents the adhesive joint thus obtained from breaking. after release of the transformer concerned.

Furthermore, it is then that the holding pressure P is at its lower level Pl that the possible readjustment takes place in position of the various sheets concerned, according to the process described above.

This lower level P1 of the holding pressure P must therefore not be too high, so that the relative sliding of the sheets in question necessary for their possible readjustment in position is effectively possible.

In addition, if this pressure level P1 of the holding pressure P were too high, it would result, upon release of the magnetic circuit concerned, a risk of rupture of the adhesive films interposed between cores 11A, 11B and cylinder heads 12, due to an inevitable proliferation of the sheets concerned, each of them playing in the manner of a leaf spring.

On the other hand, the lower level Pl of the holding pressure must be high enough to avoid that, under the effects of the clamping pressure F, the sheets of the cores 11A, 11B and of the yokes 12 overlap each other, of cylinder head cores.

Thus, this lower level P1 of the holding pressure P must be suitably metered

In practice, it is determined experimentally for each circuit.

It depends in particular on the number of stacked sheets, the elastic effect of which must be overcome, mentioned above, and on the surface of these sheets according to which the holding pressure is exerted.

In general, however, good results are obtained when the order of magnitude of the force due to the lower level P1 of the holding pressure P is approximately ten times less than the order of magnitude of the force due to the upper level F1 of the clamping pressure F _o

The latter itself depends on the magnetic circuit concerned, since it depends on the surface of this circuit according to which the cores and cylinder heads are faced.

In a particular application case, concerning a 6.3 KVA transformer, the force due to the clamping pressure P used was 2.2 tonnes for the lower level Fl of this clamping pressure, and 1 ton for the lower level F2 thereof, and jointly, the force due to the holding pressure P was 0.23 ton for the lower level Pl of this holding pressure _P , and 0.39 tonnes for the upper level P2 thereof.

Of course, these numerical values are given here only by way of example, and they should in no way be considered as limiting the invention.

Anyway, after any readjustment in position of the sheets concerned, provided under the lower level P1 of the holding position P, under the conditions described above, the upper level P2 of this holding pressure P allows to ensure that the setting of the adhesive used is carried out under good conditions.

FIG. 6 illustrates, by way of example, the application of the invention to a polyphase transformer, the magnetic circuit 10 of which then comprises three parallel cores 11A, 11B, 11C, namely two end cores 11A, 11B and an intermediate core 11C, joined two by two, at each of their ends, by yokes 120

Figures 9 and 10 illustrate the application of the invention to simple inductors, single-phase for Figure 9, three-phase for Figure 10, for which the corresponding cores are joined by a yoke at one of their endso

In the configuration illustrated in FIG. 8, the yokes 12 extend between the cores which they connect, so that, for three cores, there are four yokes 12.

However, according to the variant configuration illustrated by FIGS. 11 and 12, only two cylinder heads 12 are used, these extending over the entire length of the circuit 10, and being connected not only to one another by the intermediate core 11C, but also by the end cores 11A, 11B.

In such a configuration, the cores 11A, 11B, 11C still have the same length.

In addition, they each consist of a stack of sheets 15, all identical to each other.

Likewise, in such a case, the cylinder heads 12 each consist of a stack of sheets 16 all identical to each other.

But, in this case, it is along the length of the cores 11A, 11B, 11C that the clamping pressure is applied, therefore according to the arrows F ′ in FIG. 11, the pressure applied perpendicular to said cores, according to the arrows F of Figure 11, then being only a holding pressure, in reverse arrangements to those described above.

According to the variant configuration illustrated by FIGS. 13 and 14, three cylinder heads 12 are used.

One extends over the entire length of the circuit, in the manner of the yokes described with reference to FIGS. 11 and 12, while the other two each extend respectively between two cores 11A, 11b, 11C, in the manner of those described with reference to Figure 8.

In this case, pressure bonding according to the arrows F 'in FIG 13 is a g _e Serra-pressure portion and holding portion, while the pressure exerted along the arrows F of this Figure 13 is a clamping pressure .

For the configuration thus illustrated by FIGS. 13 and 14, the cores 11A, 11B, 11C still have the same length.

This is no longer the case for the configuration illustrated in FIG. 15.

Indeed, for this configuration, which provides the implementation of two yokes 12, the two end rings 11A, 11B are connected by these yokes 12, as a provision t _i is similar to that illustrated by Figure 8, while, for the intermediate core 11C, it is these cylinder heads 12 which are connected to each other by such an intermediate core 11C, in an arrangement similar to that illustrated by FIGS. 11 and 120

In such a case, according to the invention, the height H ′ of the circuit, taken in line with the intermediate core 11C, between the two corresponding opposite edges of the cylinder heads 12, is slightly greater than the height H of the cores 11A, 11B which those _o -ci

In other words, the height h of the intermediate core 11C and the widths 1 of the cylinder heads 12 are such that their sum cumulative is slightly greater than the height H of the end cores 11A, 11B.

As a result, the bonding, the application of a près- _if holding the yokes 12, according to arrows F 'in FIG 15, is in no way hampered by the end rings 11A, 11B, and can therefore be conducted so that this results in correct bonding of the intermediate core 11C to these cylinder heads 12.

This holding pressure F ′ and the associated clamping pressure F can be applied jointly or else successively, in one order or the other.

If desires, to improve the overall stiffness of the magnetic circuit, and prevent, at the end thereof the device in which it was assembled, it comes to de- _s unite if the glue for its implementation assembly was not then fully taken, it is possible, according to a development of the invention, to entangle two by two the cores and cylinder heads that comprises such a circuit

Preferably this entanglement is not sheet by sheet, but group of sheets by group of sheets.

According to the configuration illustrated by Figures 16 to ₂₀ . such a tangle is obtained, in a manner known per se, by subdividing the magnetic circuit concerned into three layers, and by longitudinally shifting, from one of these layers to the other, elements of cores and cylinder heads, as illustrated in the figures.

In such a case, the core elements which constitute a core have the same length, so that each of the cores _mi s in use consists of sheets all identical to each other.

on the other hand, the cylinder head elements then constituting the corresponding cylinder heads are of two different types, of different lengths, each cylinder head element however being made up of sheets which are all identical to each other.

In accordance with the configuration according to the invention illustrated by FIGS. 21 to 25, cylinder heads and cores are entangled two by two at mid-thickness at their ends, and the intermediate core 11C is formed by four elements of cores 50 ₁ , 50 ' ₁ , 50' ₂ , 50 ' ₂ superimposed two by two and joined, with a relative longitudinal offset in one direction, for two of these core elements thus superimposed, and in the opposite direction for both other.

Thus the core elements 50 ₁ and 50 ₂ , which are superimposed on each other, are offset longitudinally with respect to each other, in a first direction, while the core elements 50 ′ ₁ and 50 ′ ₂ , which are attached to the preceding ones, and which are superimposed on each other, are offset longitudinally with respect to each other, in the direction opposite to the relative offset of the core elements 50 ₁ and SO _{2 above} .

These four core elements have the same width and the same length, and, each individually, they all consist of a stack of sheets all identical to each other; the intermediate core 11C which they form is therefore, as before, made up of sheets all identical to each other.

The end cores 11A, 11B are each made up of two core elements 51 ₁ and 51 ₂ superimposed on each other, with a relative longitudinal offset in one direction for the core 11A, and in the direction opposite for core 11B.

As before, these core elements 51 ₁ and 51 ₂ all have the same width and the same length, and each individually, they all consist of sheets all identical to each other, so that the end cores 11A, 11B which they form are, as before, made of sheets all identical to each other.

Jointly, the cylinder heads 12 used, which are four in number, each consist of two cylinder head elements 53 ₁ , 53 ₂ superimposed on each other, with a relative offset relative to the other.

However, the core elements constituting the intermediate core 11C having, in the embodiment shown, a width equal to half that of the core elements constituting the end cores 11A, 11B, the cylinder head elements 53 ₁ , 53 ₂ components of cylinder heads 12 in this case do not have the same length.

In practice, their lengths differ from half the width of the cores.

For the upper layer, figure 21, there are thus two cylinder head elements 53 ₁ of greater length, and two cylinder head elements 53 ' ₁ of shorter length, and for the lower layer, figure 24, there are similarly , alternating with the previous arrangement, two cylinder head elements 53 ₂ of greater length, and two cylinder head elements 53 ' ₂ of shorter length.

But, taken each individually, these cylinder head elements all consist of a stack of sheets all identical to each other.

Such entanglement leads to a particularly effective stiffening of the magnetic circuit concerned, to handle without risk of disunion this circuit ma- g _n etic upon its release the device in which it was assembled, even when it is a relatively heavy magnetic circuit requiring, for its manipulation t _ion, to be hauled using a lanyard or similar passed around.

In all cases, from one core to another, parallel to the cylinder heads, at least one magnetic shunt can be provided, a more or less large air gap can also be left between this magnetic shunt and at least one of the cores that 'He links.

This advantageously results in an interesting development _s ant the scope of the magnetic circuit according to the invention, this scope can for example extend as that of leakage transformers and / or that of particular likely chokes to be used with advantage in the production of ferro-resonant regulators.

for example, in figure 25, there are thus two magnetic shunts 54, which extend, without gap, one between the end core 11A and the intermediate core 11C, the other between this intermediate core 11C and the core end 11B.

In addition, in this embodiment, there are still two magnetic shunts 55 which, parallel to the previous teeth, also extend one between the end core 11A and the intermediate core 11C, and the other between this intermediate core 11C and the end core 11B.

However, for magnetic shunts 55, an air gap 56 is provided between these and at least one of the cores which they connect.

In practice, in the embodiment shown, this air gap 56 is provided between the magnetic shunts 55 and the intermediate core 11C.

For example, such an air gap can be materialized by a double-sided adhesive of varying thickness securing the magnetic shunts 55 to the intermediate core 11C, and thus preventing them from vibrating during the passage of the magnetic flux.

Such a double-sided adhesive can, as a variant, be replaced by an insulator made of a more or less elastic material, in order to allow good alignment of the entire circuit and thus reduce losses at the joints between cylinder heads and cores _o

Under the same conditions, an air gap can be provided between any of the cores and any of the cylinder heads _o

This is the case in the embodiment illustrated in FIG. 27, where such an air gap 56 is provided between the intermediate core 11C and one of the yokes 12 which it connects together.

In the embodiment illustrated in FIG. 28, which combines the provisions of those illustrated in FIGS. 26 and 27, there are on the one hand magnetic shunts 45, without air gap, and on the other hand magnetic shunts 55 with air gap 56, such an air gap 56 being further provided between the intermediate core 11C and one of the cylinder heads 12 which it connects.

In all cases, on the intermediate core 11C can be engaged transversely at least one cheek made of insulating material 60.

Such a cheek 60 is shown in perspective in FIG. 29.

It is a simple frame which, in diagonally opposite positions, has a projection, parallel to two opposite edges, two legs 61.

Through its opening 62, which is quadrangular, the image of the contour of the intermediate ring 11C, such a cheek 60 can be engaged on such a core 11C intermediary such qu'illu _s - _r e in Figure 30, including centering of this intermediate core 11C when no magnetic shunt is provided.

When such magnetic shunts 54 or 55 are provided, and this is the case in the embodiment illustrated by Figure 30, wherein two magnetic shunts 54 for example are provided two flanges 60 can be carried oeu- _VRE on either side of these magnetic shunts 54 for their blocking, said cheeks being arranged so that their legs 61 are directed towards one another.

These cheeks 60 therefore jointly constitute a sort of cage making it possible to ensure easy and rapid positioning of the stacks of sheets of which the magnetic shunts 54 concerned are made up.

In the configurations illustrated by FIGS. 31 and 32, the ends of the cores 11A, 11B, 11C and the cylinder heads 12, at the junction between such cores and such cylinder heads, are biased instead of being straight as before, that is to say that for example, the corresponding junctions are all mitered from one angle to another, figure 31, or that it is not so for at least some of them, figure; 2, such junctions then being by example from an angle and ending on the opposite side, as shown.

Other joining modes are also conceivable. In all cases, the central core 11C, when there is one, can be in a single element, or in two elements, as shown diagrammatically in broken lines.

Of course, the present invention is moreover not limited to the arrangements and / or configurations described and shown, but encompasses any variant.

Claims (28)

1. Method for the assembly by gluing of a magnetic circuit resulting from the stacking of sheets and comprising, suitably individualized, at least two cores (11A, 11B) parallel to each other, and at least one yoke (12) suitable for connecting said cores to at least one of their ends, this method being of the type according to which glue (17) is available between the surfaces to be faced of said cylinder head (12) and said cores (11A, 11B) and there is applied to these, in a direction perpendicular to said surfaces and therefore parallel to the plane of the sheets (15, 16) concerned, a clamping pressure specific to the desired bonding, the sheets (15, 16) constituting the cores ( 11A, 11B) and of the cylinder head (12) being left free of any joining together before the bonding to be carried out, characterized in and that, during this bonding, these sheets (15, 16) are applied, before the pressure of tightening (F), and in a direction perpendicular to their plane, moderate pressure to maintain in (P) suitable for avoiding overlapping during tightening while allowing relative displacement parallel to themselves o 2. Method according to claim 1, characterized in that the holding pressure (P) is established in two stages, and therefore passes successively from a lower level (Pl) to an upper level (P2). 3. Method according to any one of claims 1, 2, characterized in that the clamping pressure (F) is released in two stages, and therefore passes successively from one higher level (FI) to a lower level (F2). ₄ . Process according to Claims 2, 3, taken con- j _o intement, characterized in that the holding pressure (P) is established at its higher level (P2) before the clamping pressure (F) is returned to its level lower (F2). 5. Process according to claims 2, 3, taken con- j _oi ntly, characterized in that the magnitude of the force due to the lower level (Pl) of the holding pressure (P) is about ten times lower the order of magnitude of the force due to the upper level (Fl) of the clamping pressure (F). 6. A method according to any one of claims ₁ to _5, characterized in that, before application of the clamping près- _sio n (F), is applied to cores (11A, 11B) and the yoke (12) an alignment pressure (F '), in a direction perpendicular to that of the clamping pressure ( _F ) and parallel to the plane of the sheets (15,16) concerned, by abutting said cores (11A, 11B) and said cylinder head ( 12) ₀ 7. Method according to claim 6, characterized in that the application of the alignment pressure (F ') takes place after the application of the holding pressure (P) _o 8. Method according to any one of claims ₁ to 7, and according to which the adhesive used is a polymerizable adhesive requiring for its setting an activator, characterized in that, for each pair of core (11A, 11B) -casse ( 12) said glue is applied to any one of the core-cylinder head elements and the activator to the other thereof 9. Method according to any one of claims ₁ to 8, characterized in that the adhesive used comprises a ferrite charge. 10. Device for the assembly by gluing of a magnetic circuit resulting from the stacking of sheets and comprising, suitably individualized, at least two parallel cores (11A, 11B) and at least one yoke (12) suitable for connecting said cores at at least one of their ends, characterized in that it comprises, for the considered end of the cores (11A, 11B) or breech (s) (12) a receptacle (21) suitable for placing place of these, means of clamping g _e ( ₂₃ , 24) capable of exerting a clamping pressure on the assembly thus formed of the cores and cylinder head (s), in a direction perpendicular to the confrontation surfaces between them, and holding means (22, 27) capable of exerting a holding pressure on said assembly, in a direction perpendicular to the plane of the sheets constituting said cores (11A, 11B) and cylinder head (s) (12). 11. Device according to claim 10, characterized in that said clamping means (23,24) comprise a jack (24) and a stop (23) delimiting the receptacle (21) at its end opposite to said jack (24) 0 12. Device according to any one of claims 10, 11, characterized in that said holding means (22,27) comprise a sole (22) which belongs to the receptacle (21), and at least one jack (27), possibly in combination with a removable distribution sill (33). 13. Device according to claim 12, characterized in that the jack (27) that the holding means comprise is a rotary jack, its piston (28) carries a T-shaped cross member (29), and at said cross member (29) it is associated laterally with a fixed stop (30) which is preferably adjustable in height, and on which bears said cross member (29) when said jack (27) exerts a holding pressure. 14. Device according to any one of claims 10 to 13, characterized in that it further comprises alignment means (37) suitable for exerting on the assembly constituted by the cores (11A, 11B) and cylinder head ( 12) an alignment pressure in a direction perpendicular both to the direction in which the clamping pressure is exerted and to that in which the holding pressure is exerted. 15. Device according to claim 14, characterized in that said alignment means (37) comprise a jack (37) capable of exerting alignment pressure on a distribution sill (39) mounted movably in the receptacle (21) concerned, perpendicular to the direction in which the clamping pressure is exerted. ₁₆ . A magnetic circuit for electrical apparatus, in particular transformer, of the kind comprising at least two cores (11A, 11B) parallel and at least one yoke (12) _r e-linking to each other said cores (11A, 11B) to one of their _' ends, cores (11A, 11B, 11C) and cylinder head (12) each consisting of a stack of sheets, characterized in that, in combination, on the one hand cores (11A, 11B, 11C ) and cylinder head (s) (12) are joined two by two by gluing, and on the other hand the sheets constituting one at least of the cores (11A, 11B, 11C) and / or cylinder head (s) (12) are identical to each other. ₁₇ . Magnetic circuit according to claim 16, characterized in that, two yokes (12) being provided, connected to each other by an intermediate core (11C) its thickness (H '), taken in line with said intermediate core (11C ), between the two corresponding opposite edges of said yokes (12), is slightly greater than the height (H) of the cores (11A, 11C) which these connect. ₁ 8. Magnetic circuit according to claim 16, characterized in that, an intermediate core (11C) being provided, yokes (12) and cores (11A, 11B, 11C) are entangled two by two at mid-thickness at their ends, and the intermediate core (11C) is formed by four core elements (50 ₁ , 50 ' ₁ , 50 ₂ , 50' ₂ ) superimposed in pairs and joined together with a relative longitudinal offset in one direction, for two (50 ₁ , 50 ₂ ) of these core elements thus superimposed, and in the opposite direction, for the other two (50 ′ ₁ , 50 ′ ₂ ). 19. Magnetic circuit according to claim 18, characterized in that the four core elements (50 ₁ , 50 ₂ , 50 ' ₁ , 50' ₂ ) forming the intermediate core (11C) have the same width and the same length and consist of sheets all identical to each other. 20. Magnetic circuit according to any one of claims 16 to 19, characterized in that, from one core (11A, 11B, 11C) to another, it comprises, parallel to the yokes (12), at least one magnetic shunt (54.55) ₀ 21. Magnetic circuit according to claim 20, characterized in that, for at least one magnetic shunt (55), an air gap (56) is provided between this magnetic shunt (55) and at least one of the cores (11A, 11B, 11C) which it connects. 22. Magnetic circuit according to any one of claims 16 to 21, characterized in that, for at least one core assembly (11A, 11B, 11C) -casse (12), an air gap (56) is left between such a core and such a breech. 23. Magnetic circuit according to any one of claims 21, 22, characterized in that said air gap (56) is materialized by an insulator made of elastic material. 24. Magnetic circuit according to any one of claims 16 to 23, characterized in that, on the intermediate core (11C) is engaged transversely at least one cheek (60) of insulating material. 25. Magnetic circuit according to claim 24, characterized in that, in diagonally opposite positions, said cheek (60) has, projecting, parallel to two opposite edges, two tabs (61). 26. Magnetic circuit according to any one of claims 16 to 25, characterized in that, apart from at least part of their edges, the sheets constituting the cores (11A, 11B, 11C) and / or yoke (s ) (12) are devoid of any connection between them transversely to their plans. 27. Magnetic circuit according to any one of claims 16 to 26, characterized in that the adhesive between cores (11A, 11B, 11C) and cylinder head (s) (12) comprises a ferrite charge. 28. Electrical equipment, in particular transformer, of the kind comprising a magnetic circuit, characterized in that said magnetic circuit conforms to any one of claims 16 to 27.

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