(51) Int Cl.: H01F 30/12 ( )

Transkript

1 (19) TEPZZ 7_ 76B_T (11) EP B1 (12) EUROPEAN PATENT SPECIFICATION (45) Date of publication and mention of the grant of the patent: Bulletin 2017/29 (51) Int Cl.: H01F 30/12 ( ) (21) Application number: (22) Date of filing: (54) Laminated "Y"-core transformer Laminierter Y-Kerntransformator Transformateur à noyau Y stratifié (84) Designated Contracting States: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR (30) Priority: US (43) Date of publication of application: Bulletin 2014/14 (73) Proprietor: Hamilton Sundstrand Corporation Windsor Locks, CT (US) (72) Inventors: Wilkinson, Scott P. German Valley, IL 639 (US) Clemmons, James H. Freeport, IL 632 (US) (74) Representative: Leckey, David Herbert Dehns St Bride s House Salisbury Square London EC4Y 8JD (GB) (56) References cited: CH-A US-A US-A US-A US-A EP B1 Note: Within nine months of the publication of the mention of the grant of the European patent in the European Patent Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the Implementing Regulations. Notice of opposition shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). Printed by Jouve, PARIS (FR)

2 1 EP B1 2 Description DETAILED DESCRIPTION BACKGROUND [0001] The present invention is related to transformers, and in particular to the geometry and construction of transformers. [0002] Transformers are used in a variety of applications to step-up and/or step down voltages, while providing galvanic isolation between an input and an output. In a multi-phase transformer, windings associated with each phase are wrapped around separate legs of a magnetic core. Impedance variations between the plurality of legs results in phase imbalances that negatively affect transformer performance. [0003] A transformer, "Y"-shaped magnetic core and process of manufacturing "Y"-shaped magnetic cores with the features of the preamble of claims 1, 7 and 9 is disclosed in US SUMMARY [0004] From one aspect, the present invention provides a transformer in accordance with claim 1. [0005] From another aspect, the present invention provides a "Y"-shaped magnetic core in accordance with claim 7. [0006] From yet another aspect, the present invention provides a process of manufacturing "Y"-shaped magnetic cores in accordance with claim 9. BRIEF DESCRIPTION OF THE DRAWINGS [0007] Fig. 1 is a side view of a traditional "E/I"-shaped magnetic core transformer as known in the prior art. Fig. 2 is a top view of a "Y"-shaped magnetic core transformer according to an embodiment of the present invention. Fig. 3 is an isometric view of a multi-phase transformer having a Y -shaped magnetic core according to an embodiment of the present invention. Fig. 4 is a top view of a single lamination employed in the Y-shaped magnetic core according to an embodiment of the present invention. Fig. 5 is an exploded view of a top half and bottom half of the Y-shaped magnetic core according to an embodiment of the present invention. Fig. 6 is an isometric view of the Y-shaped magnetic core as assembled according to an embodiment of the present invention. Fig. 7 is a cross-sectional view of the Y-shaped magnetic core according to an embodiment of the present invention [0008] Fig. 1 is a side view of "E/I"-shaped magnetic core transformer as known in the prior art. In this type of configuration, transformer includes three separate core limbs 12a, 12b, and 12c, each connected to one another. A plurality of input windings 14a, 14b, and 14c are wound around core limbs 12a, 12b, and 12c, respectively. Likewise, a plurality of output windings 16a, 16b, and 16c are wound around core limbs 12a, 12b, and 12c, respectively. Magnetic flux generated in core limb 12a is communicated to core limb 12b, via magnetic flux path 18, and to core limb 12c via magnetic flux path 18. A consequence of the "E/I" geometry is that magnetic flux path 18 is shorter than magnetic flux path 18. As a result, the impedance associated with magnetic flux path 18 is less than the impedance associated with magnetic flux path 18. This difference in impedance generates imbalances in the phase outputs 16a, 16b, and 16c. [0009] Fig. 2 is a top view of "Y"-shaped magnetic core transformer 20 according to an embodiment of the present invention. Transformer 20 includes "Y"-shaped magnetic core 21, which includes three core limbs 22a, 22b, and 22c, each connected to one another in a "Y" configuration. A plurality of input windings 24a, 24b, and 24c and a plurality of output windings 26a, 26b, and 26c are wrapped around each core limb 22a, 22b, and 22c, respectively. Magnetic flux generated in core limb 22a is communicated to both core limb 22b via magnetic flux path 28 and to core limb 22c via magnetic flux path 28. However, in contrast with the "E/I"-shaped geometry illustrated in Fig. 1, the length of magnetic flux paths 28 and 28 in the "Y"-shaped geometry are equal to one another. Furthermore, magnetic flux paths between the other phases (e.g., between phase C and B) would similarly have a length equal to magnetic flux paths 28 and 28. With this configuration, there is no substantial difference in the length of magnetic flux paths between respective core limbs, and therefore no substantial difference in impedance between each of the plurality of core limbs. [00] Fig. 3 is an isometric view of transformer 20 having Y -shaped magnetic core 21 according to an embodiment of the present invention. As discussed with respect to Fig. 2, transformer 20 includes "Y"-shaped magnetic core 21, which includes three core limbs 22a, 22b, and 22c, each connected to one another in a "Y" configuration. Each core limb 22a-22c extends radially outward from key hole mechanism 30, which is located in a center portion of magnetic core 21. Key hole mechanism 30 has an irregular shape that ensures all laminates (shown in Figs. 4 and 5) are aligned properly during assembly. In addition, the radially outward portion of each core limb 22a, 22b, and 22c turns downward (as shown in Fig. 4) and provides a leg around which input and output coils are wound. [0011] Fig. 4 is an exploded view of magnetic core 21 according to an embodiment of the present invention. In 2

3 3 EP B1 4 the embodiment shown in Fig. 4, magnetic core 21 includes top portion 40 and bottom portion 42. Both top portion 40 and bottom portion 42 are identical and interchangeable with one another, and may be constructed using the same manufacturing process. Both top portion 40 and bottom portion 42 are constructed of a plurality of laminates, an example of which is shown in Fig. 5, and which are visible at the end of each core limb 22a, 22b, 22c, 22a, 22b, and 22c. To ensure communication of magnetic flux from, for example, core limb 22a to core limb 22a, the laminates associated with each core limb must be aligned properly. To this end, key hole mechanism 30 is used to ensure correct position of each laminate during the manufacturing and assembly process, such that when top portion 40 and bottom portion 42 are brought together, laminates associated with each are aligned. [0012] Fig. 5 is a top view of single lamination 50 employed in Y-shaped magnetic core 21 according to an embodiment of the present invention. In the embodiment shown in Fig. 5, laminate 50 has been punched out or otherwise formed to create the desired "Y"-shaped geometry. In addition, keyhole mechanism 30 is also punched out or formed in laminate 50. A benefit of the present invention is the utilization of two-dimensional laminates which are easier to manufacture than threedimensional shapes. [0013] To form top portion 40 or bottom portion 42, a plurality of laminates 50 are stacked on top of one another to form a cylinder of "Y"-shaped laminates. Each core limb 22a, 22b, and 22c, is then bent to form the desired core limb geometry. Keyhole mechanism 30 may once again be utilized to maintain an exact position of laminates 50 during the stacking and bending process. In particular, keyhole mechanism 30 ensures that each laminate 50 is held in the same position, and ensures that during the bending process all core limbs 22a, 22b, and 22c are bent at the same location. Bending the plurality of laminates results in varying lengths at the end of each core limb. To provide a smooth end surface between core limbs associated with top portion 40 and bottom portion 42, the ends of each core limb 22a, 22b, and 22c are cut to form a flat surface. [0014] Fig. 6 is an isometric view of Y-shaped magnetic core 21 as assembled according to an embodiment of the present invention. In the embodiment shown in Fig. 6, the plurality of laminates 50 making up top portion 40 and bottom portion 42 are illustrated. In particular, each laminate 50 in top portion 40 is lined up with a counterpart laminate in bottom portion 42. It is important that laminates are aligned between top portion 40 and bottom portion 42. Keyhole mechanism 30 during the stacking and bending process ensures both top portion 40 and bottom portion 42 are identical, and will therefore align properly when stacked as shown in Fig. 6. [0015] Fig. 7 is a cross-sectional view of Y-shaped magnetic core 21 according to an embodiment of the present invention. In the embodiment shown in Fig. 7, top portion 40 and bottom portion 42 are secured to one another by bolt 60 and nut 62. In particular, bolt 60 is inserted through keyhole mechanism 30 located in both top portion 40 and bottom portion 42, and secured by nut 62. In one embodiment, bolt 60 is inserted through spacer 64 before being secured by nut 62. Spacer 64 provides a gap between top portion 40 and bottom portion 42 that is dictated by the length of spacer 64. Claims 1. A transformer (20) comprising: a "Y"-shaped magnetic core (21) that includes a top portion (40) and a bottom portion (42), wherein the top portion (40) and the bottom (42) portion both include a plurality of "Y"-shaped laminates (50) stacked on top of one another and bent to form a plurality of core limbs (22a, 22b, 22c); a plurality of input windings (24a, 24b, 24c) wound around each of the plurality of core limbs (22a, 22b, 22c); and a plurality of output windings (26a, 26b, 26c) wound around each of the plurality of core limbs (22a, 22b, 22c), wherein the top portion (40) and the bottom portion (42) are oriented such that the plurality of core limbs (22a, 22b, 22c) in the top portion (40) are aligned with the plurality of core limbs (22a, 22b, 22c) in the bottom portion (42) and characterised in that the top portion (40) and the bottom portion (42) include a key hole mechanism (30) formed in a center portion of each of the laminates (50) associated with a core limb and aligning each of the laminates (50) with one another in the same orientation and the key hole mechanism (30) having an irregular shape. 2. The transformer (20) of claim 1, including: a bolt (60) inserted through the key hole mechanism (30) in both the top portion (40) and the bottom portion (42) of the "Y"-shaped magnetic core (21) to maintain alignment of the top portion (40) and the bottom portion (42). 3. The transformer (20) of claim 2, further including: a nut (62) attached to the bolt (60) to secure the top portion (40) to the bottom portion (42). 4. The transformer (20) of claim 3, further including: a spacer (64) located between the top portion (40) and the bottom portion (42) that maintains a desired gap between the top portion (40) and 3

4 5 EP B1 6 the bottom portion (42) when secured to one another. 5. The transformer (20) of any preceding claim, wherein a magnetic flux path (28, 28 ) is created in each of the plurality of core limbs (22a, 22b, 22c) and each is of substantially equal length to another. 6. The transformer (20) of claim 5, wherein the impedance associated with the plurality of magnetic flux paths (28, 28 ) are substantially equal. 7. A "Y"-shaped magnetic core (21) comprising: a first plurality of "Y"-shaped laminates (50) stacked together to form a top portion (40) having a plurality of core limbs (22a, 22b, 22c) defined by the "Y"-shape of the laminates (50); a second plurality of "Y"-shaped laminates (50) tacked together to form a bottom portion (42) having a plurality of core limbs (22a, 22b, 22c) defined by the "Y"-shape of the laminates (50); and a mechanism (60) that secures the top portion (40) to the bottom portion (42), such that the plurality of core limbs (22a, 22b, 22c) associated with the top portion (40) are aligned with the plurality of core limbs (22a, 22b, 22c) associated with the bottom portion (42); characterised in that: each of the first and second plurality of "Y"- shaped laminates (50) includes a key hole mechanism (30) located in a center of each laminate (50) to allow each of the plurality of laminates (50) to be aligned with one another in the same orientation and the key hole mechanism (30) has an irregular shape. 8. The "Y"-shaped magnetic core (21) of claim 7, wherein the mechanism that secures the top portion (40) and the bottom portion (42) is a bolt (60) inserted through the key hole mechanism (30) in the top portion (40) and the bottom portion (42), wherein the bolt (60) is keyed to ensure alignment between the top portion (40) and the bottom portion (42). 9. A process of manufacturing a "Y"-shaped magnetic cores (21), the process comprising: stamping a plurality of "Y"-shaped laminate sections (50); stacking a first plurality of "Y"-shaped laminate sections (50) to create a top portion (40), having "Y" shaped legs (22a, 22b, 22c); stacking a second plurality of "Y"-shaped lamination sections (50) to create a bottom (42) portion having "Y" shaped legs (22a, 22b, 22c); bending each "Y" shaped leg (22a, 22b, 22c) associated with the top portion (40) and the bottom portion (42); cutting an end of each "Y" shaped leg (22a, 22b, 22c) to create an even surface at the end of each "Y" shaped leg (22a, 22b, 22c); stacking the top portion (40) with the bottom portion (42), wherein the ends of the "Y" shaped legs (22a, 22b, 22c) of the top portion (40) are aligned with the ends of the "Y" shaped legs (22a, 22b, 22c) of the bottom portion (42); and securing the top portion (40) to the bottom portion (42); characterised in that: stamping a plurality of "Y"-shaped laminates (50) includes stamping a key hole mechanism (30) at a center of each laminate (50) wherein the key hole mechanism (30) has an irregular shape.. The manufacturing process of claim 9, wherein the key hole mechanism (30) is utilized during the stacking and bending of the top portions (40) and the bottom portions to maintain consistency between the top portion (40) and the bottom portion (42). 11. The manufacturing process of claim 9 or, wherein the key hole mechanism (30) is utilized during the stacking of the top portion (40) with the bottom portion (42) to maintain alignment between laminates (50) on the ends of the "Y" shaped legs (22a, 22b, 22c). Patentansprüche 1. Transformator (20), der Folgendes umfasst: einen Y-förmigen Magnetkern (21), der einen oberen Teil (40) und einen unteren Teil (42) umfasst, wobei sowohl der obere Teil (40) als auch der untere (42) Teil eine Mehrzahl Y-förmiger Laminate (50) umfasst, die übereinander gestapelt sind und so gebogen sind, dass sie eine Mehrzahl von Kerngliedern (22a, 22b, 22c) bilden; eine Mehrzahl von Eingangswicklungen (24a, 24b, 24c), die um jedes aus der Mehrzahl von Kerngliedern (22a, 22b, 22c) gewickelt sind; und eine Mehrzahl von Ausgangswicklungen (26a, 26b, 26c), die um jedes aus der Mehrzahl von Kerngliedern (22a, 22b, 22c) gewickelt sind, wobei der obere Teil (40) und der untere Teil (42) so ausgerichtet sind, dass die Mehrzahl von Kerngliedern (22a, 22b, 22c) in dem oberen Teil (40) an der Mehrzahl von Kerngliedern (22a, 4

5 7 EP B1 8 22b, 22c) in dem unteren Teil (42) ausgerichtet ist, und dadurch gekennzeichnet, dass der obere Teil (40) und der untere Teil (42) einen Schlüssellochmechanismus (30) umfassen, der in einem mittleren Teil jedes der mit einem Kernglied verbundenen Laminate (50) ausgebildet ist und die Laminate (50) jeweils mit der gleichen Ausrichtung aneinander ausrichtet, und der Schlüssellochmechanismus (30) eine unregelmäßige Form aufweist. 2. Transformator (20) nach Anspruch 1, der Folgendes umfasst: eine durch den Schlüssellochmechanismus (30) in sowohl den oberen Teil (40) als auch den unteren Teil (42) des Y-förmigen Magnetkerns (21) eingesetzte Schraube (60), um die Ausrichtung des oberen Teils (40) und des unteren Teils (42) beizubehalten (50) definierter Kernglieder (22a, 22b, 22c) aufweist, gestapelt sind; und einen Mechanismus (60), der den oberen Teil (40) an dem unteren Teil (42) befestigt, sodass die Mehrzahl dem oberen Teil (40) zugeordneter Kernglieder (22a, 22b, 22c) an der Mehrzahl dem unteren Teil (42) zugeordneter Kernglieder (22a, 22b, 22c) ausgerichtet ist; dadurch gekennzeichnet, dass: jedes aus der ersten und der zweiten Mehrzahl Y-förmiger Laminate (50) einen Schlüssellochmechanismus (30) umfasst, der in einer Mitte jedes Laminats (50) angeordnet ist, um zu ermöglichen, es jedem aus der Mehrzahl von Laminaten (50) zu gestatten, in der gleichen Ausrichtung aneinander ausgerichtet zu werden, und der Schlüssellochmechanismus (30) eine unregelmäßige Form aufweist. 3. Transformator (20) nach Anspruch 2, der Folgendes umfasst: eine an der Schraube (60) angebrachte Mutter (62), um den oberen Teil (40) an dem unteren Teil (42) zu befestigen. 4. Transformator (20) nach Anspruch 3, der Folgendes umfasst: Y-förmiger Magnetkern (21) nach Anspruch 7, wobei es sich bei dem Mechanismus, der den oberen Teil (40) und den unteren Teil (42) aneinander befestigt, um eine Schraube (60) handelt, die durch den Schlüssellochmechanismus (30) in den oberen Teil (40) und den unteren Teil (42) eingesetzt ist, wobei die Schraube (60) verkeilt ist, um eine Ausrichtung zwischen dem oberen Teil (40) und dem unteren Teil (42) zu gewährleisten. einen zwischen dem oberen Teil (40) und dem unteren Teil (42) angeordneten Abstandshalter (64), der einen gewünschten Zwischenraum zwischen dem oberen Teil (40) und dem unteren Teil (42) bei Befestigung aneinander beibehält. 5. Transformator (20) nach einem der vorstehenden Ansprüche, wobei ein Magnetflussweg (28, 28 ) in jedem aus der Mehrzahl von Kerngliedern (22a, 22b, 22c) erzeugt wird und jeder im Wesentlichen die gleiche Länge wie ein anderer aufweist. 6. Transformator (20) nach Anspruch 5, wobei die mit der Mehrzahl von Magnetflusswegen (28, 28 ) verbundene Impedanz im Wesentlichen einheitlich ist. 7. Y-förmiger Magnetkern (21), der Folgendes umfasst: eine erste Mehrzahl Y-förmiger Laminate (50), die unter Bildung eines oberen Teils (40), der eine Mehrzahl durch die Y-Form der Laminate (50) definierter Kernglieder (22a, 22b, 22c) aufweist, gestapelt sind; eine zweite Mehrzahl Y-förmiger Laminate (50), die unter Bildung eines unteren Teils (42), der eine Mehrzahl durch die Y-Form der Laminate Verfahren zur Herstellung Y-förmiger Magnetkerne (21) wobei das Verfahren Folgendes umfasst: Stanzen einer Mehrzahl Y-förmiger Laminatabschnitte (50); Stapeln einer ersten Mehrzahl Y-förmiger Laminatabschnitte (50), um einen oberen Teil (40) mit Y-förmigen Beinen (22a, 22b, 22c) zu erzeugen; Stapeln einer ersten Mehrzahl Y-förmiger Laminatabschnitte (50), um einen unteren Teil (42) mit Y-förmigen Beinen (22a, 22b, 22c) zu erzeugen; Biegen jedes mit dem oberen Teil (40) und dem unteren Teil (42) verbundenen Y-förmigen Beins (22a, 22b, 22c); Abschneiden eines Endes jedes Y-förmigen Beins (22a, 22b, 22c), um eine ebene Oberfläche am Ende jedes Y-förmigen Beins (22a, 22b, 22c) zu erzeugen; Stapeln des oberen Teils (40) und des unteren Teils (42), wobei die Enden der Y-förmigen Beine (22a, 22b, 22c) des oberen Teils (40) an den Enden der Y-förmigen Beine (22a, 22b, 22c) des unteren Teils (42) ausgerichtet werden; und Befestigen des oberen Teils (40) an dem unteren Teil (42) ; 5

6 9 EP B1 dadurch gekennzeichnet, dass: das Stanzen einer Mehrzahl Y-förmiger Laminate (50) das Stanzen eines Schlüssellochmechanismus (30) an einer Mitte jedes Laminats (50) umfasst, wobei der Schlüssellochmechanismus (30) eine unregelmäßige Form aufweist.. Herstellungsverfahren nach Anspruch 9, wobei der Schlüssellochmechanismus (30) während des Stapelns und Biegens der oberen Teile (40) und der unteren Teile verwendet wird, um eine Übereinstimmung zwischen dem oberen Teil (40) und dem unteren Teil (42) beizubehalten Transformateur (20) de la revendication 1, comprenant : un boulon (60) inséré à travers le mécanisme en trou de serrure (30) à la fois dans la partie supérieure (40) et dans la partie inférieure (42) du noyau magnétique en forme de «Y» (21) pour maintenir l alignement de la partie supérieure (40) et de la partie inférieure (42). 3. Transformateur (20) de la revendication 2, comprenant également : un écrou (62) fixé au boulon (60) pour fixer la partie supérieure (40) à la partie inférieure (42). 11. Herstellungsverfahren nach Anspruch 9 oder, wobei der Schlüssellochmechanismus (30) während des Stapelns des oberen Teils (40) und des unteren Teils (42) verwendet wird, um die Ausrichtung zwischen den Laminaten (50) an den Enden der Y-förmigen Beine (22a, 22b, 22c) beizubehalten. Revendications 1. Transformateur (20) comprenant : un noyau magnétique en forme de «Y» (21) qui comprend une partie supérieure (40) et une partie inférieure (42), dans lequel la partie supérieure (40) et la partie inférieure (42) comprennent tous les deux une pluralité de stratifiées en forme de «Y» (50) empilées les unes sur les autres et repliées pour former une pluralité de branches de noyau (22a, 22b, 22c) ; une pluralité de bobines d entrée (24a, 24b, 24c) enroulées autour de chacune de la pluralité des branches de noyau (22a, 22b, 22c) ; et une pluralité de bobines de sortie (26a, 26b, 26c) enroulées autour de chacune de la pluralité des branches de noyaux (22a, 22b, 22c), dans lequel la partie supérieure (40) et la partie inférieure (42) sont orientées de sorte que la pluralité des branches de noyau (22a, 22b, 22c) dans la partie supérieure (40) est alignée avec la pluralité des branches de noyau (22a, 22b, 22c) dans la partie inférieure (42) et caractérisée en ce que la partie supérieure (40) et la partie inférieure (42) comprennent un mécanisme en trou de serrure (30) formée dans une position centrale de chacune des stratifiées (50) associées à une branche de noyau et l alignement de chacune des stratifiées (50) les unes avec les autres dans la même orientation et le mécanisme en trou de serrure (30) ayant une forme irrégulière Transformateur (20) de la revendication 3, comprenant également : une entretoise (64) située entre la partie supérieure (40) et la partie inférieure (42) qui maintient un espace souhaité entre la partie supérieure (40) et la partie inférieure (42) lorsqu elles sont fixées l une à l autre. 5. Transformateur (20) d une quelconque revendication précédente, dans lequel un trajet de flux magnétique (28, 28 ) est créé dans chacune de la pluralité des branches de noyau (22a, 22b, 22c) et chacune étant sensiblement de la même longueur que l autre. 6. Transformateur (20) de la revendication 5, dans lequel l impédance associée à la pluralité des trajets de flux magnétique (28, 28 ) est sensiblement égale. 7. Noyau magnétique en forme de «Y» (21) comprenant : une première pluralité de stratifiées en forme de «Y» (50) empilées ensemble pour former une partie supérieure (40) ayant une pluralité de branches de noyau (22a, 22b, 22c) définie par les stratifiées en forme de «Y» (50) ; une seconde pluralité de stratifiées en forme de «Y» (50) empilées ensemble pour former une partie inférieure (42) ayant une pluralité de branches de noyau (22a, 22b, 22c) définie par les stratifiées en forme de «Y» (50) ; et un mécanisme (60) qui fixe la partie supérieure (40) à la partie inférieure (42), de sorte que la pluralité de branches de noyau (22a, 22b, 22c) associée à la partie supérieure (40) est alignée avec la pluralité de branches de noyau (22a, 22b, 22c) associées à la partie inférieure (42) ; caractérisé en ce que : chacune de la première et de la seconde pluralité de stratifiées en forme de «Y» (50) 6

7 11 EP B1 12 comprend un mécanisme en trou de serrure (30) situé dans un centre de chaque stratifiée (50) pour permettre à chacune de la pluralité des stratifiées (50) d être alignée les unes aux autres dans la même orientation et le mécanisme en trou de serrure (30) a une forme irrégulière. 8. Noyau magnétique en forme de «Y» (21) de la revendication 7, dans lequel le mécanisme qui fixe la partie supérieure (40) et la partie inférieure (42) est un boulon (60) inséré à travers le mécanisme en trou de serrure (30) dans la partie supérieure (40) et la partie inférieure (42), dans lequel le boulon (60) est verrouillé pour assurer l alignement entre la partie supérieure (40) et la partie inférieure (42) supérieures (40) et des parties inférieures pour maintenir une cohérence entre la partie supérieure (40) et la partie inférieure (42). 11. Procédé de fabrication de la revendication 9 ou, dans lequel le mécanisme en trou de serrure (30) est utilisé au cours de l empilement de la partie supérieure (40) avec la partie inférieure (42) pour maintenir l alignement entre les stratifiées (50) sur les extrémités des branches en forme de «Y» (22a, 22b, 22c). 9. Procédé de fabrication de noyaux magnétiques en forme de «Y» (21), le procédé comprenant : l emboutissage d une pluralité de sections de stratifiées en forme de «Y» (50) ; l empilement d une première pluralité de sections de stratifiée en forme de «Y» (50) pour créer une partie supérieure (40), ayant des branches en forme de «Y» (22a, 22b, 22c) ; l empilement d une seconde pluralité de sections de stratifiée en forme de «Y» (50) pour créer une partie inférieure (42), ayant des branches en forme de «Y» (22a, 22b, 22c) ; le pliage de chaque branche en forme de «Y» (22a, 22b, 22c) associée à la partie supérieure (40) et la partie inférieure (42) ; la découpe d une extrémité de chaque branche en forme de «Y» (22a, 22b, 22c) pour créer une surface égale à l extrémité de chaque branche en forme de «Y» (22a, 22b, 22c) ; l empilement de la partie supérieure (40) avec la partie inférieure (42), dans lequel les extrémités des branches en forme de «Y» (22a, 22b, 22c) de la partie supérieure (40) sont alignées avec les extrémités des branches en forme de «Y» (22a, 22b, 22c) de la partie inférieure (42) ; et la fixation de la partie supérieure (40) à la partie inférieure (42) ; caractérisé en ce que : l emboutissement d une pluralité de stratifiées en forme de «Y» (50) comprend l emboutissage d un mécanisme en trou de serrure (30) au niveau d un centre de chaque stratifiée (50) dans lequel le mécanisme en trou de serrure (30) a une forme irrégulière.. Procédé de fabrication de la revendication 9, dans lequel le mécanisme en trou de serrure (30) est utilisé au cours de l empilement et du pliage des parties

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14 EP B1 REFERENCES CITED IN THE DESCRIPTION This list of references cited by the applicant is for the reader s convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard. Patent documents cited in the description US A [0003] 14