EP0122850A1 - VHF power transformer - Google Patents

VHF power transformer Download PDF

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Publication number
EP0122850A1
EP0122850A1 EP84400686A EP84400686A EP0122850A1 EP 0122850 A1 EP0122850 A1 EP 0122850A1 EP 84400686 A EP84400686 A EP 84400686A EP 84400686 A EP84400686 A EP 84400686A EP 0122850 A1 EP0122850 A1 EP 0122850A1
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EP
European Patent Office
Prior art keywords
plate
inductors
grooves
housing
cut
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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EP84400686A
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German (de)
French (fr)
Inventor
Jean Hermelin
Yves Renvoise
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Thales SA
Original Assignee
Thomson CSF SA
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Publication of EP0122850A1 publication Critical patent/EP0122850A1/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F17/00—Fixed inductances of the signal type 
    • H01F17/0006—Printed inductances
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/08—Cooling; Ventilating
    • H01F27/22—Cooling by heat conduction through solid or powdered fillings

Definitions

  • the invention relates to a transformer for very high frequency and high intensity currents such as those used in VHF radio transmitters.
  • a transformer consists of a plurality of inductors coupled together. These inductances dissipate a significant amount of heat when the current flowing through them has a high intensity.
  • These inductors are enclosed in a box constituting a radioelectric shielding and a heat sink. In general it is necessary that the characteristics of the inductors are precise, to be reproducible easily in series, and that they have a low coefficient of temperature.
  • the transformers thus obtained cannot dissipate a high power because the thin thickness of the metal sheet, around 50 microns, and the poor conductivity of the insulating substrate, which is generally a glass fiber fabric impregnated with epoxy resin, do not allow not sufficient heat transmission, and because the low decomposition temperature of the resin does not allow a high operating temperature.
  • the transformer according to the invention overcomes these drawbacks by simple means.
  • the transformer according to the invention has two inductors, 1 and 2, identical and coupled together. They each have the shape of a flat spiral cut from a copper plate 500 microns thick and covered on both sides with a layer of electrolytic silver 5 microns thick. The high thickness of metal provides good thermal conductivity and the silver coating provides good pellicular electrical conductivity.
  • Inductors 1 and 2 are bonded to a plate 3, made of 96% alumina ceramic with a thickness of 1.27 millimeters. In order to. transmit the heat dissipated by the inductor, and not cause additional losses, the ceramic used has a thermal conductivity greater than 0.05 cal.cm/cm 2 .s.
  • the adhesive used must be able to withstand a temperature at least equal to 150 ° C, have a thermal conductivity at least equal to 0.002 cal.cm/cm 2. s. ° C, and have a shear breaking load at least equal to 6 000 psi to resist the difference in expansion of copper and ceramic.
  • the adhesive used is of the ABLEBOND 789-1 type manufactured by ABLESTICK LABORATORIES USA.
  • a hole is drilled in the ceramic to fix a female socket, 9, 10, 11, 12, perpendicular to the plate 3.
  • the two inductors, 1 and 2 are glued on the same face of the plate 3, but the sockets 9 and 10 of the inductor 1 are located on a first face while the sockets 11 and 12 of the inductor 2 are located on the second face of the plate 3.
  • Each socket has at one end, in the extension of its axis of revolution, a pin of diameter equal to the diameter of the hole drilled in the ceramic and of length greater than the thickness of the ceramic plate, so as to allow a weld on the metal of the inductor, either on the first face, or on the second face of the plate 3.
  • sockets 11 and 12 are located on the side of the second face, their pins passing through the ceramic and make it possible to weld them to the inductor 2 which is bonded to the first face of the plate 3
  • Sockets 9 and 10 are welded at their base to inductance 1, c ar they are located on the side of the first face.
  • Inductors 1 and 2 are cut from the same copper foil by chemical attack.
  • the parts of this sheet, which are intended to constitute the inductors, were protected by a photosensitive resin which was exposed by a photographic process, then treated with a solvent to remove the resin covering the parts of the copper which must be attacked.
  • To maintain the inductors in a well-defined relative position provision is made to leave copper bridges between the two inductors 1 and 2, and inside the spiral of each of them. These copper bridges are removed after the bonding operation, by grinding, or by sand blasting. This process provides excellent reproducibility of the characteristics of the inductors.
  • the plate 3 is enclosed in a housing constituting a radio shield and a heat sink. It is made of aluminum covered with an electrolytic deposit of copper, 15 microns thick, and a silver deposit 7 microns thick. It comprises a hollow profile 5, closed at its two ends by two attached flanges, 4 and 6.
  • the hollow profile 5 has a rectangular internal section and an external section comprising a wide longitudinal flange allowing the housing to be fixed on a flat surface and transmit dissipated heat to this surface by the transformer.
  • Profile 5 has two grooves 13 and 15 hollowed inside, parallel to its major axis. They are located in the plane of symmetry of the profile 5. Their length and their spacing are respectively equal to the length and the width of the plate 3. Their width is greater than the thickness of the plate 3.
  • the plate 3 is inserted in these grooves.
  • the walls of the profile 5 have a thickness of 8 millimeters except in the grooves 13 and 15.
  • the grooves have a depth of 6 millimeters.
  • the periphery of the second face of the plate 3 is in contact with a first wall of the groove 13 and with a first wall of the groove 15, under the pressure respectively of two accordion springs 7 and 8, which are inserted respectively between the first face of the plate 3 and a second wall of the groove 13, and between the first face of the plate 3 and a second wall of the groove 15.
  • the grooves 13 and 15 respectively comprise a recess 14 and a recess 16 making it possible to maintain in place the springs 7 and 8.
  • the inductors 1 and 2 are located on the plate 3 sufficiently far from the edges to avoid any contact with the metal case.
  • the heat, dissipated in the inductors 1 and 2 is conducted by the ceramic plate 3 then is transmitted to the housing through the contact zone, of large surface, existing on the first faces of the grooves 13 and 15. This surface corresponds to the depth of the grooves 13 and 15 and the length of the plate 3.
  • This contact is permanently maintained by the accordion springs 7 and 8, which also absorb dimensional variations due to temperature variations.
  • the puddles 4 and 6 are cut from a plate 8 millimeters thick in the shape of the section of the section 5, and are fixed to the latter by four screws not shown in the figure.
  • Two holes, 17 and 18, are drilled in the section 5, in a face parallel to the plate 3, and open opposite the sockets 9 and 10 in order to allow the connection of a connection on these sockets.
  • Two other holes are drilled in the opposite face of the profile 5, and are not shown in the figure, they allow the connection of connections on the sockets 11 and 12 at the ends of the inductor 2.
  • the reproducibility is + 0.5%
  • the overvoltage coefficient is greater than 150
  • the temperature coefficient is lower at 10 -4
  • the dissipable power is 16 watts, for a frequency range from 30 to 90 megahertz.
  • the transformer according to the invention it is within the reach of those skilled in the art to adapt the transformer according to the invention to increase the number of inductors, or the number of taps on each inductor, to use a type of spring different from that of the springs. accordion 7 and 8, or to use a different housing, the essential characteristic being that a non-negligible surface of the periphery of the plate 3 has good thermal contact with the metal of the housing. It is possible to machine the inductors by any etching method used to make printed circuits, but it is also possible to use other methods to precisely machine a thin metal plate.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Coils Or Transformers For Communication (AREA)

Abstract

Power transformers for currents of very high frequency, in particular for use in radio transmitters. The transformer comprises two inductors (1 and 2) cut from a single sheet of copper using a photographic and chemical process, and then bonded to a ceramic plate (3). Copper bridges between the two inductors (1 and 2) and inside their spiral allow the relative position, and hence the characteristics of the two inductors (1, 2) to be defined accurately. The bridges are removed after the bonding operation. Pins (9, 10, 11, 12) allow connections to be made with the inductors (1 and 2). The ceramic plate (3) is enclosed within a box comprising two slots (13 and 15) with which it is held in contact with the metal of the box by two pleated springs (7 and 8) so as to transmit to the box (5) the heat dissipated by the inductors (1 and 2) and transmitted by the ceramic plate (3). Application to VHF radio transmitters. <IMAGE>

Description

L'invention concerne un transformateur pour des courants de très haute fréquence et d'intensité élevée tels que ceux utilisés dans les émetteurs radio VHF. Un tel transformateur est constitué d'une pluralité d'inductances couplées entre elles. Ces inductances dissipent une quantité importante de chaleur lorsque le courant qui les parcourt a une intensité élevée. Ces inductances sont enfermées dans un boîtier constituant un blindage radioélectrique et un dissipateur thermique. En général il est nécessaire que les caractéristiques des inductances soient précises, pour être reproductibles facilement en séries, et qu'elles possèdent un faible coefficient de température.The invention relates to a transformer for very high frequency and high intensity currents such as those used in VHF radio transmitters. Such a transformer consists of a plurality of inductors coupled together. These inductances dissipate a significant amount of heat when the current flowing through them has a high intensity. These inductors are enclosed in a box constituting a radioelectric shielding and a heat sink. In general it is necessary that the characteristics of the inductors are precise, to be reproducible easily in series, and that they have a low coefficient of temperature.

Il est connu de réaliser un tel transformateur en bobinant du fil de cuivre argenté sur un mandrin en céramique comportant un filetage pour définir la position du fil. Ce procédé a pour inconvénient une mauvaise reproductibilité des caractéristiques des inductances, notamment de leurs coefficients de mutuelle induction qui dépendent de leur position relative. D'autre part, il est connu de réaliser des transformateurs VHF, de faible puissance, en gravant une pluralité d'inductances sur un substrat pour circuits imprimés par un des procédés classiques de réalisation de circuits imprimés. Les transformateurs ainsi obtenus ne peuvent pas dissiper une puissance élevée parce que la faible épaisseur de la feuille métallique, environ 50 microns, et la mauvaise conductibilité du substrat isolant, qui est en général un tissu de fibres de verre imprégné de résine époxy, ne permettent pas une transmission suffisante de la chaleur, et parce que la faible température de décomposition de la résine ne permet pas une température de fonctionnement élevée. Le transformateur selon l'invention remédie à ces inconvénients par des moyens simples.It is known to produce such a transformer by winding silver copper wire on a ceramic mandrel having a thread to define the position of the wire. This process has the drawback of poor reproducibility of the characteristics of the inductors, in particular their mutual induction coefficients which depend on their relative position. On the other hand, it is known to produce VHF transformers, of low power, by etching a plurality of inductances on a substrate for printed circuits by one of the conventional methods of making printed circuits. The transformers thus obtained cannot dissipate a high power because the thin thickness of the metal sheet, around 50 microns, and the poor conductivity of the insulating substrate, which is generally a glass fiber fabric impregnated with epoxy resin, do not allow not sufficient heat transmission, and because the low decomposition temperature of the resin does not allow a high operating temperature. The transformer according to the invention overcomes these drawbacks by simple means.

Selon l'invention un transformateur VHF de puissance, est caractérisé en ce qu'il comporte :

  • - une pluralité d'inductances découpées dans une même feuille métallique ayant une faible résistance thermique, et revêtues d'un dépôt métallique très bon conducteur électrique ;
  • - une plaque d'un matériau ayant de faibles pertes électriques aux très hautes fréquences et une faible résistance thermique, plaque sur laquelle est collée la pluralité d'inductances, par une colle ayant une faible résistance thermique et une bonne tenue aux variations de température ; une partie de la surface de la plaque, sur sa périphérie, étant laissée inoccupée ;
  • - un boîtier métallique enfermant la plaque ;
  • - des moyens pour maintenir en contact le boîtier avec la partie non occupée de la plaque, pour transmettre la chaleur qui est dégagée par la pluralité d'inductances et qui est transmise par la plaque, afin de dissiper cette chaleur dans l'atmosphère à l'extérieur du boîtier.
According to the invention, a VHF power transformer, is characterized in that it comprises:
  • - a plurality of inductors cut from the same metal sheet having low thermal resistance, and coated with a deposit metallic very good electrical conductor;
  • - A plate of a material having low electrical losses at very high frequencies and a low thermal resistance, plate on which is glued the plurality of inductors, by an adhesive having a low thermal resistance and good resistance to temperature variations; a part of the surface of the plate, on its periphery, being left unoccupied;
  • - a metal case enclosing the plate;
  • - Means for keeping the housing in contact with the unoccupied part of the plate, for transmitting the heat which is released by the plurality of inductors and which is transmitted by the plate, in order to dissipate this heat in the atmosphere at outside the housing.

L'invention sera mieux comprise et d'autres détails apparaîtront à l'aide de la description suivante et de la figure l'accompagnant, qui représente un exemple de réalisation du transformateur selon l'invention.The invention will be better understood and other details will appear with the aid of the following description and the accompanying figure, which represents an exemplary embodiment of the transformer according to the invention.

Dans cet exemple de réalisation le transformateur selon l'invention comporte deux inductances, 1 et 2, identiques et couplées entre elles. Elles ont chacune la forme d'une spirale plane découpée dans une plaque de cuivre de 500 microns d'épaisseur et recouverte des deux côtés d'une couche d'argent électrolytique de 5 microns d'épaisseur. La forte épaisseur de métal procure une bonne conductibilité thermique et le revêtement d'argent procure une bonne conductibilité électrique pélliculaire. Les inductances 1 et 2 sont collées sur une plaque 3, en céramique à 96 % d'alumine ayant une épaisseur de 1,27 millimètres. Afin de. transmettre la chaleur dissipée par la self, et ne pas provoquer des pertes supplémentaires, la céramique utilisée a une conductibilité thermique supérieure à 0,05 cal.cm/cm2.s.°C, et un angle de perte à 100 MHz dont la tangente est inférieure à 5.10-4. Dans cet exemple elle est du type TS1 fabriqué par L.C.C (France). La colle utilisée doit pouvoir supporter une température au moins égale à 150°C, avoir une conductibilité thermique au moins égale à 0,002 cal.cm/cm2.s.°C, et avoir une charge de rupture au cisaillement au moins égale à 6 000 p.s.i. afin de résister à la différence de dilatation du cuivre et de la céramique. Dans cet exemple la colle utilisée est du type ABLEBOND 789-1 fabriqué par ABLESTICK LABORATORIES USA. A chaque extrémité des inductances 1 et 2, un trou est percé dans la céramique pour fixer une douille femelle, 9, 10, 11, 12, perpendiculaire à la plaque 3. Les deux inductances, 1 et 2, sont collées sur une même face de la plaque 3, mais les douilles 9 et 10 de l'inductance 1 sont situées sur une première face alors que les douilles 11 et 12 de l'inductance 2 sont situées sur la deuxième face de la plaque 3. Chaque douille possède à une extrémité, dans le prolongement de son axe de révolution, un picot de diamètre égal au diamètre du trou percé dans la céramique et de longueur supérieure à l'épaisseur de la plaque de céramique, de façon à permettre une soudure sur le métal de l'inductance, soit sur la première face, soit sur la deuxième face de la plaque 3. Dans cet exemple les douilles 11 et 12 sont situées du côté de la deuxième face, leurs picots traversant la céramique et permettent de les souder à l'inductance 2 qui est collée sur la première face de la plaque 3. Les douilles 9 et 10 sont soudées à leur base sur l'inductance 1, car elles sont situées du côté de la première face.In this exemplary embodiment, the transformer according to the invention has two inductors, 1 and 2, identical and coupled together. They each have the shape of a flat spiral cut from a copper plate 500 microns thick and covered on both sides with a layer of electrolytic silver 5 microns thick. The high thickness of metal provides good thermal conductivity and the silver coating provides good pellicular electrical conductivity. Inductors 1 and 2 are bonded to a plate 3, made of 96% alumina ceramic with a thickness of 1.27 millimeters. In order to. transmit the heat dissipated by the inductor, and not cause additional losses, the ceramic used has a thermal conductivity greater than 0.05 cal.cm/cm 2 .s. ° C, and a loss angle at 100 MHz whose tangent is less than 5.10 -4 . In this example, it is of the TS1 type manufactured by LCC (France). The adhesive used must be able to withstand a temperature at least equal to 150 ° C, have a thermal conductivity at least equal to 0.002 cal.cm/cm 2. s. ° C, and have a shear breaking load at least equal to 6 000 psi to resist the difference in expansion of copper and ceramic. In this example, the adhesive used is of the ABLEBOND 789-1 type manufactured by ABLESTICK LABORATORIES USA. At each end of inductors 1 and 2, a hole is drilled in the ceramic to fix a female socket, 9, 10, 11, 12, perpendicular to the plate 3. The two inductors, 1 and 2, are glued on the same face of the plate 3, but the sockets 9 and 10 of the inductor 1 are located on a first face while the sockets 11 and 12 of the inductor 2 are located on the second face of the plate 3. Each socket has at one end, in the extension of its axis of revolution, a pin of diameter equal to the diameter of the hole drilled in the ceramic and of length greater than the thickness of the ceramic plate, so as to allow a weld on the metal of the inductor, either on the first face, or on the second face of the plate 3. In this example the sockets 11 and 12 are located on the side of the second face, their pins passing through the ceramic and make it possible to weld them to the inductor 2 which is bonded to the first face of the plate 3 Sockets 9 and 10 are welded at their base to inductance 1, c ar they are located on the side of the first face.

Les inductances 1 et 2 sont découpées dans une même feuille de cuivre par une attaque chimique. Les parties de cette feuille, qui sont destinées à constituer les inductances, ont été protégées par une résine photosensible qui a été insolée par un procédé photographique, puis traitée par un solvant pour enlever la résine couvrant les parties du cuivre qui doivent être attaquées. Pour maintenir les inductances dans une position relative bien déterminée, il est prévu de laisser des ponts de cuivre entre les deux inductances 1 et 2, et à l'intérieur de la spirale de chacune d'elles. Ces ponts de cuivre sont éliminés après l'opération de collage, par un meulage, ou par une abrasion au jet de sable. Ce procédé permet d'obtenir une excellente reproductibilité des caractéristiques des inductances.Inductors 1 and 2 are cut from the same copper foil by chemical attack. The parts of this sheet, which are intended to constitute the inductors, were protected by a photosensitive resin which was exposed by a photographic process, then treated with a solvent to remove the resin covering the parts of the copper which must be attacked. To maintain the inductors in a well-defined relative position, provision is made to leave copper bridges between the two inductors 1 and 2, and inside the spiral of each of them. These copper bridges are removed after the bonding operation, by grinding, or by sand blasting. This process provides excellent reproducibility of the characteristics of the inductors.

La plaque 3 est enfermée dans un boîtier constituant un blindage radioélectrique et un dissipateur de chaleur. Il est réalisé en aluminium recouvert d'un dépôt électrolytique de cuivre, de 15 microns d'épaisseur, et un dépôt d'argent de 7 microns d'épaisseur. Il comprend un profilé creux 5, fermé à ses deux extrémités par deux flasques rapportés, 4 et 6. Le profilé creux 5 a une section interne rectangulaire et une section externe comportant une semelle longitudinale large permettant de fixer le boîtier sur une surface plane et de transmettre à cette surface la chaleur dissipée par le transformateur. Le profilé 5 comporte deux rainures 13 et 15 creusées à l'intérieur, parallèlement à son grand axe. Elles sont situées dans le plan de symétrie du profilé 5. Leur longueur et leur écartement sont respectivement égaux à la longueur et à la largeur de la plaque 3. Leur largeur est supérieure à l'épaisseur de la plaque 3. La plaque 3 est insérée dans ces rainures. Les parois du profile 5 ont une épaisseur de 8 millimètres sauf dans les rainures 13 et 15. Les rainures ont une profondeur de 6 millimètres. La périphérie de la seconde face de la plaque 3 est en contact avec une première paroi de la rainure 13 et avec une première paroi de la rainure 15, sous la pression respectivement de deux ressorts en accordéon 7 et 8, qui sont insérés respectivement entre la première face de la plaque 3 et une seconde paroi de la rainure 13, et entre la première face de la plaque 3 et une seconde paroi de la rainure 15. Les rainures 13 et 15 comportent respectivement un décrochement 14 et un décrochement 16 permettant de maintenir en place les ressorts 7 et 8. Naturellement les inductances 1 et 2 sont situées sur la plaque 3 suffisamment éloignées des bords pour éviter tout contact avec le boîtier métallique. La chaleur, dissipée dans les inductances 1 et 2, est conduite par la plaque de céramique 3 puis est transmise au boîtier grâce à la zone de contact, de surface importante, existant sur les premières faces des rainures 13 et 15. Cette surface correspond à la profondeur des rainures 13 et 15 et à la longueur de la plaque 3. Ce contact est maintenu en permanence par les ressorts en accordéon 7 et 8, qui absorbent aussi les variations dimentionnelles dues aux variations de température. Les flaques 4 et 6 sont découpés dans une plaque de 8 millimètres d'épaisseur à la forme de la section du profilé 5, et sont fixés à celui-ci par quatre vis non représentées sur la figure. Deux trous, 17 et 18, sont percés dans le profilé 5, dans une face parallèle à la plaque 3, et débouchent en face des douilles 9 et 10 afin de permettre le branchement d'une connexion sur ces douilles. Deux autres trous sont percés dans la face opposée du profilé 5, et ne sont pas représentés sur la figure, ils permettent le branchement de connexions sur les douilles 11 et 12 aux extrémités de l'inductance 2.The plate 3 is enclosed in a housing constituting a radio shield and a heat sink. It is made of aluminum covered with an electrolytic deposit of copper, 15 microns thick, and a silver deposit 7 microns thick. It comprises a hollow profile 5, closed at its two ends by two attached flanges, 4 and 6. The hollow profile 5 has a rectangular internal section and an external section comprising a wide longitudinal flange allowing the housing to be fixed on a flat surface and transmit dissipated heat to this surface by the transformer. Profile 5 has two grooves 13 and 15 hollowed inside, parallel to its major axis. They are located in the plane of symmetry of the profile 5. Their length and their spacing are respectively equal to the length and the width of the plate 3. Their width is greater than the thickness of the plate 3. The plate 3 is inserted in these grooves. The walls of the profile 5 have a thickness of 8 millimeters except in the grooves 13 and 15. The grooves have a depth of 6 millimeters. The periphery of the second face of the plate 3 is in contact with a first wall of the groove 13 and with a first wall of the groove 15, under the pressure respectively of two accordion springs 7 and 8, which are inserted respectively between the first face of the plate 3 and a second wall of the groove 13, and between the first face of the plate 3 and a second wall of the groove 15. The grooves 13 and 15 respectively comprise a recess 14 and a recess 16 making it possible to maintain in place the springs 7 and 8. Naturally the inductors 1 and 2 are located on the plate 3 sufficiently far from the edges to avoid any contact with the metal case. The heat, dissipated in the inductors 1 and 2, is conducted by the ceramic plate 3 then is transmitted to the housing through the contact zone, of large surface, existing on the first faces of the grooves 13 and 15. This surface corresponds to the depth of the grooves 13 and 15 and the length of the plate 3. This contact is permanently maintained by the accordion springs 7 and 8, which also absorb dimensional variations due to temperature variations. The puddles 4 and 6 are cut from a plate 8 millimeters thick in the shape of the section of the section 5, and are fixed to the latter by four screws not shown in the figure. Two holes, 17 and 18, are drilled in the section 5, in a face parallel to the plate 3, and open opposite the sockets 9 and 10 in order to allow the connection of a connection on these sockets. Two other holes are drilled in the opposite face of the profile 5, and are not shown in the figure, they allow the connection of connections on the sockets 11 and 12 at the ends of the inductor 2.

- Dans un exemple de réalisation où les inductances ont une valeur de 75 nanohenrys, la reproductibilité est de + 0,5 %, le coefficient de surtension est supérieur à 150, le coefficient de température est inférieur à 10-4, la puissance dissipable est de 16 watts, pour une gamme de fréquence allant de 30 à 90 mégahertz. - In an exemplary embodiment where the inductors have a value of 75 nanohenrys, the reproducibility is + 0.5%, the overvoltage coefficient is greater than 150, the temperature coefficient is lower at 10 -4 , the dissipable power is 16 watts, for a frequency range from 30 to 90 megahertz.

11 est à la portée de l'homme de l'art d'adapter le transformateur selon l'invention pour augmenter le nombre d'inductances, ou le nombre de prises sur chaque inductance, pour utiliser un type de ressort différent de celui des ressorts en accordéon 7 et 8, ou pour utiliser un boîtier différent, la caractéristique essentielle étant qu'une surface non négligeable de la périphérie de la plaque 3 ait un bon contact thermique avec le métal du boîtier. Il est possible d'usiner les inductances par toute méthode de gravure utilisée pour réaliser des circuits imprimés, mais il est possible aussi d'utiliser d'autres méthodes permettant d'usiner avec précision une plaque de métal mince.It is within the reach of those skilled in the art to adapt the transformer according to the invention to increase the number of inductors, or the number of taps on each inductor, to use a type of spring different from that of the springs. accordion 7 and 8, or to use a different housing, the essential characteristic being that a non-negligible surface of the periphery of the plate 3 has good thermal contact with the metal of the housing. It is possible to machine the inductors by any etching method used to make printed circuits, but it is also possible to use other methods to precisely machine a thin metal plate.

Claims (4)

1. Transformateur VHF de puissance, caractérisé en ce qu'il comporte : - une pluralité d'inductances (1, 2), découpées dans une même feuille métallique ayant une faible résistance thermique, et revêtues d'un dépôt métallique très bon conducteur électrique ; - une plaque (3) d'un matériau ayant de faibles pertes électriques aux très hautes fréquences et une faible résistance thermique, plaque sur laquelle est collée la pluralité d'inductances, par une colle ayant une faible résistance thermique et une bonne tenue aux variations de température ; une partie de la surface de la plaque (3), sur sa périphérie, étant laissée inoccupée ; - un boîtier métallique (4, 5, 6) enfermant la plaque (3) ; - des moyens (7, 8, 14, 16) pour maintenir en contact le boîtier (5) avec la partie non occupée de la plaque (3), pour transmettre la chaleur qui est dégagée par la pluralité d'inductances et qui est transmise par la plaque (3), afin de dissiper cette chaleur dans l'atmosphère à l'extérieur du boîtier (4, 5, 6). 1. VHF power transformer, characterized in that it comprises: - a plurality of inductors (1, 2), cut from the same metal sheet having low thermal resistance, and coated with a metal deposit which is a very good electrical conductor; - A plate (3) of a material having low electrical losses at very high frequencies and a low thermal resistance, plate on which the plurality of inductors is bonded, by an adhesive having a low thermal resistance and good resistance to variations temperature; a part of the surface of the plate (3), on its periphery, being left unoccupied; - a metal case (4, 5, 6) enclosing the plate (3); - Means (7, 8, 14, 16) for maintaining in contact the housing (5) with the unoccupied part of the plate (3), for transmitting the heat which is released by the plurality of inductors and which is transmitted by the plate (3), in order to dissipate this heat in the atmosphere outside the housing (4, 5, 6). 2. Transformateur selon la revendication 1, caractérisé en ce que le boîtier métallique est constitué d'un profilé métallique creux (5), fermé à ses deux extrémités par deux flasques (4 et 6) rapportés, et comporte deux rainures (13 et 15), parallèles à son axe, situées en vis-à-vis, et de largeur supérieure à l'épaisseur de la plaque (3) ; en ce que la plaque (3) comporte deux bords parallèles, et a une largeur, entre ces deux bords, égale à la distance entre les fonds respectifs des deux rainures (13 et 15) pour pouvoir être placée dans ces deux rainures (13 et 15) ; et en ce que ce transformateur comporte des ressorts (7 et 8) placés dans les rainures pour maintenir en contact la plaque (3) et le boîtier (5) dans les rainures (13 et 15).2. Transformer according to claim 1, characterized in that the metal housing consists of a hollow metal profile (5), closed at its two ends by two attached flanges (4 and 6), and has two grooves (13 and 15 ), parallel to its axis, located opposite, and of width greater than the thickness of the plate (3); in that the plate (3) has two parallel edges, and has a width, between these two edges, equal to the distance between the respective bottoms of the two grooves (13 and 15) in order to be able to be placed in these two grooves (13 and 15); and in that this transformer has springs (7 and 8) placed in the grooves to keep the plate (3) and the housing (5) in contact in the grooves (13 and 15). 3. Transformateur selon la revendication 1, caractérisé en ce que les inductances (1, 2), découpées dans une même feuille métallique, sont maintenues solidiaires par des ponts, faisant partie de cette feuille, pendant que ces inductances sont collées sur la plaque (3) ; et en ce que ces ponts sont supprimés après qu'elles ont été collées.3. Transformer according to claim 1, characterized in that the inductors (1, 2), cut from the same metal sheet, are held together by bridges, forming part of this sheet, while these inductors are glued to the plate ( 3); and in that these bridges are removed after they have been pasted. 4. Transformateur selon la revendication 3, caractérisé en ce que la pluralité d'inductances est découpée dans une même feuille métallique par une attaque chimique, les parties destinées à constituer les inductances (1, 2) étant protégées par une résine qui est gravée par un procédé photographique.4. Transformer according to claim 3, characterized in that the plurality of inductors is cut from the same metal sheet by a chemical attack, the parts intended to constitute the inductors (1, 2) being protected by a resin which is etched by a photographic process.
EP84400686A 1983-04-15 1984-04-06 VHF power transformer Withdrawn EP0122850A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8306220A FR2544543B1 (en) 1983-04-15 1983-04-15 VHF POWER TRANSFORMER
FR8306220 1983-04-15

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EP0122850A1 true EP0122850A1 (en) 1984-10-24

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Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4751717A (en) * 1985-04-30 1988-06-14 Peter Chenausky RF transformer and diagnostic technique therefor
FR2692736B1 (en) * 1992-06-23 1996-12-20 Thomson Csf HIGH AND MEDIUM POWER RADIOELECTRIC FILTER.

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB812162A (en) * 1956-03-20 1959-04-22 Ferranti Ltd Improvements relating to electrical transformers
FR1400674A (en) * 1964-05-23 1965-05-28 Kyoei Sangyo Kabushiki Kaisha Set of printed windings with laminate structure
GB1172254A (en) * 1966-04-30 1969-11-26 Int Standard Electric Corp Improvements in or relating to Printed Circuit Inductances and Transformers
DE1903602A1 (en) * 1969-01-24 1970-08-13 Siemens Ag Transmitter with at least one conductive layer arranged between winding layers
DE1942960A1 (en) * 1969-08-23 1971-03-04 Grundig Emv Housing for a module intended for installation in electrical communications equipment, which contains a small transformer
US3883834A (en) * 1973-12-13 1975-05-13 Gen Electric Ballast transformer with heat dissipating device
DE3149853C1 (en) * 1981-12-16 1983-04-07 May & Christe Gmbh, Transformatorenwerke, 6370 Oberursel Inductance or transformer with plastic moulded end covers

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB812162A (en) * 1956-03-20 1959-04-22 Ferranti Ltd Improvements relating to electrical transformers
FR1400674A (en) * 1964-05-23 1965-05-28 Kyoei Sangyo Kabushiki Kaisha Set of printed windings with laminate structure
GB1172254A (en) * 1966-04-30 1969-11-26 Int Standard Electric Corp Improvements in or relating to Printed Circuit Inductances and Transformers
DE1903602A1 (en) * 1969-01-24 1970-08-13 Siemens Ag Transmitter with at least one conductive layer arranged between winding layers
DE1942960A1 (en) * 1969-08-23 1971-03-04 Grundig Emv Housing for a module intended for installation in electrical communications equipment, which contains a small transformer
US3883834A (en) * 1973-12-13 1975-05-13 Gen Electric Ballast transformer with heat dissipating device
DE3149853C1 (en) * 1981-12-16 1983-04-07 May & Christe Gmbh, Transformatorenwerke, 6370 Oberursel Inductance or transformer with plastic moulded end covers

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FR2544543B1 (en) 1985-06-14
FR2544543A1 (en) 1984-10-19

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