EP0005386A1 - Inductance with a ferrite pot core and method to adjust the reluctance of the core - Google Patents

Inductance with a ferrite pot core and method to adjust the reluctance of the core Download PDF

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Publication number
EP0005386A1
EP0005386A1 EP79400217A EP79400217A EP0005386A1 EP 0005386 A1 EP0005386 A1 EP 0005386A1 EP 79400217 A EP79400217 A EP 79400217A EP 79400217 A EP79400217 A EP 79400217A EP 0005386 A1 EP0005386 A1 EP 0005386A1
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EP
European Patent Office
Prior art keywords
magnetic circuit
reluctance
value
adjustment
inductance
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Granted
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EP79400217A
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German (de)
French (fr)
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EP0005386B1 (en
Inventor
Alexis Nepomiastchy
Robert Le Dosseur
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Societe Anonyme de Telecommunications SAT
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Societe Anonyme de Telecommunications SAT
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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 
    • H01F17/04—Fixed inductances of the signal type  with magnetic core
    • H01F17/043—Fixed inductances of the signal type  with magnetic core with two, usually identical or nearly identical parts enclosing completely the coil (pot cores)
    • 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
    • H01F27/42—Circuits specially adapted for the purpose of modifying, or compensating for, electric characteristics of transformers, reactors, or choke coils

Definitions

  • the present invention relates to a magnetic circuit shaped as a ferrite pot constituted by the superposition of two half-shells and provided with an air gap in its central core. It also relates to the method of adjusting the reluctance of such a magnetic ferrite circuit in order to give it a reluctance of predetermined value.
  • the adjustment is obtained by modifying the passage section and the distribution of the lines of magnetic force in the area of the air gap.
  • each half-shell has a base surmounted by a more or less hollowed out outer crown and a central core.
  • the height of the outer crown is significantly greater than that of the central core.
  • the central core comprises a cylindrical chimney allowing the rotational movement and the translation of a ferrite rod secured to a screw, called a screw adjustment, movable in a nut integral with one of the two half-shells.
  • the positioning of the ferrite rod in the vicinity and / or more or less inside the air gap of the magnetic circuit makes it possible to obtain adjustments having an accuracy of the order of 10-4 and a usual adjustment margin of 15 %.
  • the present invention aims to overcome the drawbacks mentioned above by providing a magnetic circuit whose adjustment of its reluctance to a predetermined value is obtained by machining and removal of material at least in one of the surfaces facing the central core forming the air gap of the magnetic circuit. This surface modification results in a modification of the distribution of the magnetic force lines and an increase in the reluctance of the magnetic circuit.
  • the adjustment method according to the invention does not use a stick that is introduced more or less into the air gap using an adjustment screw and eliminates all the drawbacks inherent in said screw adjustment. Additionally, the absence of a central chimney along the core of a magnetic circuit according to the invention improves the qualities of the magnetic circuit.
  • a magnetic circuit of the type defined in the entry into material is characterized, in accordance with the invention, in that at least one of the two half-shells which are assembled and immobilized by gluing or stapling, comprises in the vicinity of the air gap a thin wall whose partial and gradual piercing gradually increases the reluctance value of the magnetic circuit to a predetermined value.
  • the gradual and partial piercing of the thin wall is carried out by means of a laser beam whose emission is modulated by pulses of controllable duration and intensity.
  • an automatic machine is advantageously used for adjusting said magnetic circuits, essentially comprising a laser source for machining the thin wall, an apparatus for measuring a significant parameter of the reluctance of the magnetic circuit and a computer.
  • the measuring device can be a self-inductance or frequency measuring device.
  • a Al be the variation of self-inductance produced by the drilling of a hole of diameter 0.
  • the elementary variation ⁇ Al is proportional to the square of the diameter of the hole.
  • the total variation ⁇ ⁇ Al due to the drilling of several holes having diameters ⁇ 1 , ⁇ 2 , ⁇ 3 ...., ⁇ n is proportional to the sum of the squares of these diameters k is a proportionality coefficient whose value depends on the very pa- of the ferrite magnetic circuit.
  • the relative value of the setting ⁇ ⁇ A1 / Al can be very large, 25% and more; it suffices for this, according to the invention, to give the thin adjustment wall a dimension accordingly and to make in said wall one or more holes having more or less large diameters.
  • the essential object of the invention is magnetic circuits made of ferrite, the relative setting value of which is of the order of 10% of their self-inductance coefficients.
  • the adjustment method according to the invention achieves a high control accuracy, of the order of 10- 4, and even better if necessary because it is possible to assay very finely the amount of material removed by the action of a laser beam.
  • the adjustment process according to the invention is very rapid. This process does not use any mechanical movement in the magnetic circuit.
  • the rate of adjustment of the magnetic circuits can be very large, of the order of one circuit adjusted per second.
  • Another advantage of the magnetic circuit according to the invention and of its adjustment method lies in its high reliability.
  • the circuit according to the invention comprising no additional part, the relative precision of which can be modified after adjustment, for example under the action of temperature or vibrations, is very reliable.
  • Fig. 1 shows a sectional view of a magnetic circuit according to the invention which consists essentially of a pot formed by a lower half-shell 1 and an upper half-shell 2 which are made of ferrite.
  • the two half-shells 1 and 2 are assembled and locked by gluing or stapling at the neck with respect to their surfaces' - Ronnes 1 'and 2', after introduction of the coil 6 in the cavity of the magnetic circuit.
  • the two half-shells are not identical.
  • the lower half-shell 1 has a solid central core 1 "while the central core 2" of the upper half-shell 2 has a chimney 3, called an adjustment chimney.
  • the cores 1 "and 2" are coaxial and are separated by an air gap 4.
  • the chimney 3 has the form of a blind hole which is separated from the air gap 4 by a thin wall 5, called the adjustment wall, and which can be, for example, a cylindrical hole coaxial with the central core 2 ".
  • At 6 are shown schematically the winding (s) placed in the cavity of the magnetic circuit.
  • one or more holes, such that 7, are drilled in the adjustment wall 5. This removal of material increases the effective value of the air gap 4.
  • the magnetic circuit according to the invention has substantially the same characteristics as a magnetic circuit of identical dimensions, the central core of which would not include the adjustment chimney 3.
  • Fig. 2 shows a view of the upper face of a magnetic circuit according to the invention. This is more particularly the adaptation of a known circuit to its production according to the invention.
  • FIG. 2 shows in 2 the upper half-shell, in 3 the adjustment chimney and in 7 the adjustment hole.
  • a carcass 8 supports the winding (s) 6 and emerges in two places on the magnetic circuit.
  • Fig. 3 schematically represents an automatic machine implementing the adjustment method according to the invention, by means of a laser source.
  • the coil 6 of the magnetic circuit to be adjusted is connected to the measurement input of a self-inductance 10 (or frequency) meter.
  • a computer 11 has one of its two inputs connected to the information output of the measuring device and the other input connected to a memory with a prerecorded program 12.
  • This memory 12 has memorized the exact value of the coefficient of self-inductance which must be obtained by adjusting the magnetic circuit.
  • the computer 11 determines, by successive comparisons between the self-inductance values measured and transmitted by the measuring device 10 and the predetermined self-inductance value transmitted by the memory 12, the adjustment parameters of a laser source 14. These parameters are the orientation, intensity, duration of operation and convergence of the laser beam 15 emitted by the laser source 14.
  • a link 13 connects the output of the computer 11 and the laser source control input 14 for transporting the information necessary for adjusting the parameters of the emission of the laser beam 15.
  • a laser source 14 provides easy adjustment of a magnetic circuit according to the invention. Indeed, the removal of this ferromagnetic material necessary for said adjustment is carried out on a magnetic circuit provided with its winding and in operation. This means that this adjustment is made in dynamics and can be carried out on an inductor or a transformer comprising said magnetic circuit and interconnected in an electronic circuit in operation. As a result, the magnetic circuits formed by the inductor or the transformer are adjusted in their normal operating conditions.
  • the method of removing material by means of a laser beam does not cause any appreciable disturbance of the magnetic ferrite circuit according to the invention.
  • the adjustment wall 5 of the magnetic circuit allows machining by means of the laser beam 15 which is very localized in space and in time.
  • the computer 11 can control, as a function of different prerecorded programs in the memory 12, the operation of the laser source 14 according to different sequences.
  • Figures 4a, 4b and 4c re present, by way of example, three examples of configurations which the adjustment wall of a magnetic circuit according to the invention can have, once the adjustment thereof has been carried out.
  • the wall 5a shown in FIG. 4a has been pierced with a single hole 7a whose diameter has been calculated to obtain the predetermined self-inductance value as closely as possible.
  • the wall 5c shown in FIG. 4c corresponds to the use by the computer 11 of a program which determines, after each self-inductance measurement, the diameter of the hole 7c to be drilled in order to approach by default the predetermined self-inductance value. It will be appreciated that the holes 7c thus drilled, also centered on a coplanar spiral to the adjustment wall 5c, are becoming smaller.
  • the adjustment method according to the configuration of FIG. 4c contributes both to great speed of execution and to very precise adjustment.
  • the automatic self-inductance adjustment is performed with a precision of 10 ' -4 at the rate of one magnetic circuit per second.
  • a magnetic circuit has for example a section of the central cores 1 ", 2" of 26 mm 2 , a section of the adjustment chimney 3 of 7 mm 2 and a thickness of the adjustment wall 5c of 0.3 mm.
  • the machining is carried out by a laser beam, the emission of which is modulated by pulses with a unit duration of 0.5 ps. Each pulse allows material erosion to a depth of approximately 50 ⁇ m.
  • the half-shells 1 and 2 are different. It is obvious that for multiple reasons, among other reasons of economy, it is possible to combine, to constitute a magnetic circuit, two half-shells of identical structures without thereby departing from the scope of the present invention. In the latter case, the magnetic circuit thus formed is adjusted either simultaneously or alternately, by machining one and / or the other of the adjustment walls of the half-shells.

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

Abstract

1. Inductance comprising a magnetic circuit in the form of a casing constituted of the super-position of two ferrite half-shells (1, 2) with an airgap (4) in its central core (1", 2"), characterized in that at least one (2) of the two half-shells which are assembled and fixed by gluing or hooking, comprises near the airgap (4) a thin wall (5) which is perforated with one or more holes (7) to obtain the value of the reluctance of the magnetic circuit.

Description

La présente invention concerne un circuit magnétique conformé en un pot en ferrite constitué par la superposition de deux demi-coquilles et pourvu d'un entrefer en son noyau central. Elle a trait également au procédé de réglage de la réluctance d'un tel circuit magnétique en ferrite en vue de lui conférer une réluctance de valeur prédéterminée.The present invention relates to a magnetic circuit shaped as a ferrite pot constituted by the superposition of two half-shells and provided with an air gap in its central core. It also relates to the method of adjusting the reluctance of such a magnetic ferrite circuit in order to give it a reluctance of predetermined value.

Actuellement pour obtenir un tel réglage dans les circuits magnétiques connus, on modifie la valeur effective de leurs entrefers. Dans le cadre de l'invention, le réglage est obtenu par modification de la section de passage et de la répartition des lignes de force magnétique dans la zone de l'entrefer.Currently, to obtain such an adjustment in known magnetic circuits, the effective value of their air gaps is modified. In the context of the invention, the adjustment is obtained by modifying the passage section and the distribution of the lines of magnetic force in the area of the air gap.

De tels circuits ou pots magnétiques sont utilisés en grand nombre dans le domaine des télécommunications. En effet, l'industrie des télécommunications exploite en très grande quantité des inductances qui sont formées d'un ou plusieurs bobinages appropri és, placés dans une cavité réalisée par l'association de deux demi-coquilles ferromagnétiques . Selon une structure connue, chaque demi-coquille comporte une base surmontée d'un couronne extérieure plus ou moins évidée et d'un noyau central. La hauteur de la couronne extérieure est sensiblement supérieure à celle du noyau central. L'assemblage par superposition des deux demi-coquilles réalise un circuit magnétique dont le noyau central présente un entrefer délimité par les deux surfaces en regard du noyau central. Pour obtenir de tels circuits magnétiques ayant une valeur de réluctance prédéterminée, il y a lieu tout d'abord de prendre des précautions d'usinage sur la hauteur relative de la couronne extérieure et du noyau central. Une machine appropriée à un tel usinage est décrite dans le brevet français n° 2 293 047. Le circuit magnétique ainsi obtenu a une réluctance voisine de celle prédéterminée. On procède ensuite au . réglage de la valeur de la réluctance avec précision. Pour ce fàire, toujours dans les circuits magnétiques connus et selon l'un des procédés les plus utilisés, le noyau central comporte une cheminée cylindrique permettant le mouvement à rotation et la translation d'un bâtonnet en ferrite solidaire d'une vis, appelée vis de réglage, mobile dans un écrou solidaire de l'une des deux demi-coquilles. Le positionnement du bâtonnet en ferrite au voisinage et/ou plus ou moins à l'intérieur de l'entrefer du circuit magnétique permet d'obtenir des réglages ayant une précision de l'ordre de 10-4 et une marge usuelle de réglage de 15 %.Such circuits or magnetic pots are used in large numbers in the telecommunications field. Indeed, the telecommunications industry exploits very large quantities of inductors which are formed from one or more suitable coils, placed in a cavity produced by the association of two ferromagnetic half-shells. According to a known structure, each half-shell has a base surmounted by a more or less hollowed out outer crown and a central core. The height of the outer crown is significantly greater than that of the central core. The assembly by superposition of the two half-shells produces a magnetic circuit whose central core has an air gap defined by the two surfaces facing the central core. To obtain such magnetic circuits having a predetermined reluctance value, it is first of all necessary to take machining precautions on the relative height of the outer ring and of the central nucleus. A machine suitable for such machining is described in French Patent No. 2,293,047. The magnetic circuit thus obtained has a reluctance close to that predetermined. We then proceed to. fine adjustment of the reluctance value. For this purpose, still in known magnetic circuits and according to one of the most used methods, the central core comprises a cylindrical chimney allowing the rotational movement and the translation of a ferrite rod secured to a screw, called a screw adjustment, movable in a nut integral with one of the two half-shells. The positioning of the ferrite rod in the vicinity and / or more or less inside the air gap of the magnetic circuit makes it possible to obtain adjustments having an accuracy of the order of 10-4 and a usual adjustment margin of 15 %.

Toutefois, pour des raisons de miniaturisation, on utilise de plus en plus des circuits magnétiques de très petites dimensions. Les circuits magnétiques connus, du genre décrit ci-dessus, présentent alors au moins les inconvénients suivants :

  • - la diminution de la section utile du noyau central due à la présence de la cheminée cylindrique, et
  • - des difficultés technologiques concernant la réalisation d'une vis de réglage pourvue de bâtonnet en ferrite pour une cheminée dont le diamètre est inférieur à ou de l'ordre de 2 millimètres.
However, for reasons of miniaturization, magnetic circuits of very small dimensions are increasingly used. The known magnetic circuits, of the kind described above, then have at least the following drawbacks:
  • - the reduction in the useful section of the central core due to the presence of the cylindrical chimney, and
  • - technological difficulties concerning the production of an adjustment screw provided with a ferrite rod for a chimney whose diameter is less than or of the order of 2 millimeters.

La présente invention a pour but de s'affranchir des inconvénients évoqués ci-dessus en fournissant un circuit magnétique dont le réglage de sa réluctance à une valeur prédéterminée est obtenu par usinage et enlèvement de matière au moins dans l'une des surfaces en regard du noyau central formant l'entrefer du circuit magnétique. Cette modification de surface entraîne une modification de la répartition des lignes de force magnétique et une augmentation de la réluctance du circuit magnétique.The present invention aims to overcome the drawbacks mentioned above by providing a magnetic circuit whose adjustment of its reluctance to a predetermined value is obtained by machining and removal of material at least in one of the surfaces facing the central core forming the air gap of the magnetic circuit. This surface modification results in a modification of the distribution of the magnetic force lines and an increase in the reluctance of the magnetic circuit.

Il apparat que le procédé de réglage conforme à l'invention ne fait pas appel à un bâtonnet que l'on introduit plus ou moins dans l'entrefer à l'aide d'une vis de réglage et supprime tous les inconvénients inhérents à ladite vis de réglage. Complémentairement, l'absence d'une cheminée centrale tout le long du noyau d'un circuit magnétique conforme à l'invention améliore les qualités du circuit magnétique.It appears that the adjustment method according to the invention does not use a stick that is introduced more or less into the air gap using an adjustment screw and eliminates all the drawbacks inherent in said screw adjustment. Additionally, the absence of a central chimney along the core of a magnetic circuit according to the invention improves the qualities of the magnetic circuit.

A ces fins, un circuit magnétique du type défini dans l'entrée en matière est caractérisé, conformément à l'invention, en ce qu'au moins l'une des deux demi-coquilles qui sont assemblées et immobilisées par collage ou agrafage, comporte au voisinage de l'entrefer une paroi mince dont le percement partiel et graduel augmente graduellement la valeur de la réluctance du circuit magnétique à une valeur prédéterminée.For these purposes, a magnetic circuit of the type defined in the entry into material is characterized, in accordance with the invention, in that at least one of the two half-shells which are assembled and immobilized by gluing or stapling, comprises in the vicinity of the air gap a thin wall whose partial and gradual piercing gradually increases the reluctance value of the magnetic circuit to a predetermined value.

Selon le procédé de réglage du circuit magnétique conforme à l'invention, le percement graduel et partiel de la paroi mince est effectué au moyen d'un faisceau laser dont l'émission est modulée par des impulsions de durée et d'intensité contrôlables.According to the magnetic circuit adjustment method according to the invention, the gradual and partial piercing of the thin wall is carried out by means of a laser beam whose emission is modulated by pulses of controllable duration and intensity.

Toujours selon l'invention, on utilise avantageusement pour effectuer le réglage desdits circuits magnétiques une machine automatique comprenant essentiellement une source laser pour l'usinage de la paroi mince, un appareil de mesure d'un paramètre significatif de la réluctance du circuit magnétique et un ordinateur. L'appareil de mesure peut être un appareil de mesure de self-inductance ou de fréquence.Still according to the invention, an automatic machine is advantageously used for adjusting said magnetic circuits, essentially comprising a laser source for machining the thin wall, an apparatus for measuring a significant parameter of the reluctance of the magnetic circuit and a computer. The measuring device can be a self-inductance or frequency measuring device.

La présence d'un trou pratiqué dans la paroi mince dite de réglage qui est au contact de l'entrefer, augmente la valeur effective de l'entrefer et, par conséquent, augmente la valeur de la réluctance et diminue la valeur du coefficient de self-inductance spécifique Al. Soit A Al la variation de self-inductance produite par le perçage d'un trou de diamètre 0. Approximativement, la variation élémentaire Δ Al est proportionnelle au carré du diamètre du trou. Egalement approximativement, la variation totale Σ Δ Al dûe au perçage de plusieurs trous ayant des diamètres φ1, φ2, φ3 ...., φn est proportionnelle à la somme des carrés de ces diamètres

Figure imgb0001
k est un coefficient de proportionnalité dont la valeur dépend des paramè- tres du circuit magnétique en ferrite.The presence of a hole made in the thin so-called adjustment wall which is in contact with the air gap, increases the effective value of the air gap and, consequently, increases the value of the reluctance and decreases the value of the self coefficient -specific inductance Al. Let A Al be the variation of self-inductance produced by the drilling of a hole of diameter 0. Approximately, the elementary variation Δ Al is proportional to the square of the diameter of the hole. Also approximately, the total variation Σ Δ Al due to the drilling of several holes having diameters φ 1 , φ 2 , φ 3 ...., φ n is proportional to the sum of the squares of these diameters
Figure imgb0001
 k is a proportionality coefficient whose value depends on the very pa- of the ferrite magnetic circuit.

Si nécessaire la valeur relative du réglage Σ ΔA1 / Al peut être très importante, 25% et plus ; il suffit pour cela, selon l'invention, de donner à la paroi mince de réglage une dimension en conséquence et de pratiquer dans ladite paroi un ou plusieurs trous ayant des diamètres plus ou moins grands.If necessary, the relative value of the setting Σ ΔA1 / Al can be very large, 25% and more; it suffices for this, according to the invention, to give the thin adjustment wall a dimension accordingly and to make in said wall one or more holes having more or less large diameters.

Cependant l'invention a pour objet essentiel les circuits magnétiques en ferrite dont la valeur relative de réglage est de l'ordre de 10% de leurs coefficients de self-inductance. Le procédé de réglage selon l'invention permet d'atteindre une très grande précision de réglage, de l'ordre de 10-4, et même mieux si nécessaire, car il est possible de doser de façon très fine la quantité de matière enlevée par l'action d'un faisceau à rayonnement laser.However, the essential object of the invention is magnetic circuits made of ferrite, the relative setting value of which is of the order of 10% of their self-inductance coefficients. The adjustment method according to the invention achieves a high control accuracy, of the order of 10- 4, and even better if necessary because it is possible to assay very finely the amount of material removed by the action of a laser beam.

Etant donné que les circuits magnétiques utilisés dans les matériels de télécommunications sont employés avec une induction magnétique très faible, de l'ordre d'un dixième de millitesla, le fait de diminuer localement la section de ferrite même de façon assez importante ne permet pas d'atteindre les valeurs voisines de l'induction de saturation qui est de l'ordre de quelques centaines de milliteslas.Since the magnetic circuits used in telecommunications equipment are used with a very weak magnetic induction, of the order of a tenth of a millitesla, the fact of locally decreasing the section of ferrite even quite significantly does not allow '' reach the values close to the saturation induction which is of the order of a few hundred milliteslas.

Le procédé de réglage selon l'invention est très rapide. Ce procédé ne met en oeuvre aucune mécanique en mouvement dans le circuit magnétique. La cadence de réglage des circuits magnétiques peut être très grande, de l'ordre d'un circuit réglé par seconde.The adjustment process according to the invention is very rapid. This process does not use any mechanical movement in the magnetic circuit. The rate of adjustment of the magnetic circuits can be very large, of the order of one circuit adjusted per second.

Un autre avantage du circuit magnétique selon l'invention et de son procédé de réglage réside dans sa grande fiabilité. Le circuit selon l'invention ne comportant aucune pièce additionnelle, dont la précision relative peut être modifiée après le réglage, par exemple sous l'action de la température ou des vibrations, est très fiable.Another advantage of the magnetic circuit according to the invention and of its adjustment method lies in its high reliability. The circuit according to the invention comprising no additional part, the relative precision of which can be modified after adjustment, for example under the action of temperature or vibrations, is very reliable.

D'autres avantages du circuit magnétique selon l'invention et de son procédé de réglage apparaîtront plus clairement au cours de la description qui suit, en référence aux dessins annexés correspondants dans lesquels :

  • - la Fig. 1 est une vue en coupe d'un circuit magnétique selon l'invention;
  • - la Fig. 2 est une vue de la face supérieure d'un circuit magnétique selon l'invention ;
  • - la Fig. 3 est un bloc-diagramme schématique d'une machine automatique mettant en oeuvre le procédé de réglage d'un circuit magnétique selon l'invention ; et
  • - les Figs. 4a, 4b et 4c représentent trois configurations préférées de la paroi mince de réglage d'un circuit magnétique selon l'invention, après réglage de celui-ci.
Other advantages of the magnetic circuit according to the invention and of its adjustment method will appear more clearly during the description which follows, with reference to the corresponding appended drawings in which:
  • - Fig. 1 is a sectional view of a magnetic circuit according to the invention;
  • - Fig. 2 is a view of the upper face of a magnetic circuit according to the invention;
  • - Fig. 3 is a schematic block diagram of an automatic machine implementing the method for adjusting a magnetic circuit according to the invention; and
  • - Figs. 4a, 4b and 4c represent three preferred configurations of the thin wall for adjusting a magnetic circuit according to the invention, after adjusting it.

La Fig. 1 représente une vue en coupe d'un circuit magnétique selon l'invention qui est constitué essentiellement d'un pot formé par une demi-coquille inférieure 1 et une demi-coquille supérieure 2 qui sont en ferrite.Fig. 1 shows a sectional view of a magnetic circuit according to the invention which consists essentially of a pot formed by a lower half-shell 1 and an upper half-shell 2 which are made of ferrite.

Les deux demi-coquilles 1 et 2 sont assemblées et immobilisées par collage ou agrafage au niveau des surfaces en regard de leurs cou'- ronnes 1' et 2', après introduction du bobinage 6 dans la cavité du circuit magnétique.The two half-shells 1 and 2 are assembled and locked by gluing or stapling at the neck with respect to their surfaces' - Ronnes 1 'and 2', after introduction of the coil 6 in the cavity of the magnetic circuit.

Selon la réalisation montrée à la Fig. 1 , les deux demi-coquilles ne sont pas identiques. La demi-coquille inférieure 1 a un noyau central plein 1" tandis que le noyau central 2" de la demi-coquille supérieure 2 présente une cheminée 3, dite cheminée de réglage. Les noyaux 1 " et 2" sont coaxiaux et sont séparés par un entrefer 4. La cheminée 3 a la forme d'un trou borgne qui est séparé de l'entrefer 4 par une paroi mince 5, dite paroi de réglage, et qui peut être, par exemple, un trou cylindrique coaxial au noyau central 2". En 6 sont représentés schématiquement le ou les bobinages placés dans la cavité du circuit magnétique. Selon le procédé de réglage, conforme à l'invention, un ou plusieurs trous, tels que 7, sont percés dans la paroi de réglage 5. Cet enlèvement de matière augmente la valeur effective de l'entrefer 4.According to the embodiment shown in FIG. 1, the two half-shells are not identical. The lower half-shell 1 has a solid central core 1 "while the central core 2" of the upper half-shell 2 has a chimney 3, called an adjustment chimney. The cores 1 "and 2" are coaxial and are separated by an air gap 4. The chimney 3 has the form of a blind hole which is separated from the air gap 4 by a thin wall 5, called the adjustment wall, and which can be, for example, a cylindrical hole coaxial with the central core 2 ". At 6 are shown schematically the winding (s) placed in the cavity of the magnetic circuit. According to the adjustment method, according to the invention, one or more holes, such that 7, are drilled in the adjustment wall 5. This removal of material increases the effective value of the air gap 4.

Il est à noter qu'avant perçage du trou 7 le circuit magnétique selon l'invention a sensiblement les mêmes caractéristiques qu'un circuit magnétique de dimensions identiques dont le noyau central ne comporterait pas la cheminée de réglage 3.It should be noted that before drilling the hole 7 the magnetic circuit according to the invention has substantially the same characteristics as a magnetic circuit of identical dimensions, the central core of which would not include the adjustment chimney 3.

La Fig. 2 représente une vue de la face supérieure d'un circuit magnétique selon l'invention. Il s'agit plus particulièrement de l'adaptation d'un circuit connu à sa réalisation selon l'invention. Sur cette figure sont représentés en 2 la demi-coquille supérieure, en 3 la cheminée de réglage et en 7 le trou de réglage. Une carcasse 8 supporte le ou les bobinages 6 et émerge en deux endroits du circuit magnétique.Fig. 2 shows a view of the upper face of a magnetic circuit according to the invention. This is more particularly the adaptation of a known circuit to its production according to the invention. In this figure are shown in 2 the upper half-shell, in 3 the adjustment chimney and in 7 the adjustment hole. A carcass 8 supports the winding (s) 6 and emerges in two places on the magnetic circuit.

La Fig. 3 représente schématiquement une machine automatique mettant en oeuvre le procédé de réglage selon l'invention, au moyen d'une source laser. Le bobinage 6 du circuit magnétique à régler est relié à l'entrée de mesure d'un appareil de mesure de self-inductance 10 (ou de fréquence). Un ordinateur 11 a Il une de ses deux entrées reliées à la sortie d'information de l'appareil de mesure et l'autre entrée reliée à une mémoire à programme pré-enregistré 12. Cette mémoire 12 a mémorisé la valeur exacte du coefficient de self-inductance qui doit être obtenu par le réglage du circuit magnétique. Selon le programme pré-enregistré dans la mémoire 12, l'ordinateur 11 détermine, par comparaisons successives entre les valeurs de self-inductance mesurées et transmises par l'appareil de mesure 10 et de la valeur prédéterminée de self-inductance transmise par la mémoire 12, les paramètres de réglage d'une source laser 14. Ces paramètres sont l'orientation, l'intensité, la durée de fonctionnement et la convergence du faisceau laser 15 émis par la source laser 14. Une liaison 13 relie la sortie de l'ordinateur 11 et l'entrée de commande de la source laser 14 pour assurer le transport des informations nécessaires aux réglages des paramètres de l'émission du faisceau laser 15.Fig. 3 schematically represents an automatic machine implementing the adjustment method according to the invention, by means of a laser source. The coil 6 of the magnetic circuit to be adjusted is connected to the measurement input of a self-inductance 10 (or frequency) meter. A computer 11 has one of its two inputs connected to the information output of the measuring device and the other input connected to a memory with a prerecorded program 12. This memory 12 has memorized the exact value of the coefficient of self-inductance which must be obtained by adjusting the magnetic circuit. According to the program prerecorded in memory 12, the computer 11 determines, by successive comparisons between the self-inductance values measured and transmitted by the measuring device 10 and the predetermined self-inductance value transmitted by the memory 12, the adjustment parameters of a laser source 14. These parameters are the orientation, intensity, duration of operation and convergence of the laser beam 15 emitted by the laser source 14. A link 13 connects the output of the computer 11 and the laser source control input 14 for transporting the information necessary for adjusting the parameters of the emission of the laser beam 15.

L'utilisation d'une source laser 14 confère un réglage aisé d'un circuit magnétique selon l'invention. En effet, l'enlèvement de cette matière ferromagnétique nécessaire audit réglage est effectué sur un circuit magnétique muni de son bobinage et en fonctionnement. Cela signifie que ce réglage est effectué en dynamique et peut être réalisé sur une inductance ou un transformateur comprenant ledit circuit magnétique et interconnecté dans un circuit électronique en fonctionnement. De ce fait, les circuits magnétiques constitués par l'inductance ou le transformateur sont réglés dans leurs conditions normales d'exploitation.The use of a laser source 14 provides easy adjustment of a magnetic circuit according to the invention. Indeed, the removal of this ferromagnetic material necessary for said adjustment is carried out on a magnetic circuit provided with its winding and in operation. This means that this adjustment is made in dynamics and can be carried out on an inductor or a transformer comprising said magnetic circuit and interconnected in an electronic circuit in operation. As a result, the magnetic circuits formed by the inductor or the transformer are adjusted in their normal operating conditions.

L'expérience a montré que le procédé d'enlèvement de matière au moyen d'un faisceau à rayonnement laser ne provoquait aucune perturbation sensible du circuit magnétique en ferrite selon l'invention. En effet, la paroi de réglage 5 du circuit magnétique permet un usinage au moyen du faisceau laser 15 qui est très localisé dans l'espace et dans le temps.Experience has shown that the method of removing material by means of a laser beam does not cause any appreciable disturbance of the magnetic ferrite circuit according to the invention. Indeed, the adjustment wall 5 of the magnetic circuit allows machining by means of the laser beam 15 which is very localized in space and in time.

En vue d'obtenir d'autres configurations de la paroi de réglage, l'ordinateur 11 peut commander, en fonction de programmes pré-enregistrés différents dans la mémoire 1 2, le fonctionnement de la source laser 14 selon des séquences différentes. Les figures 4a, 4b et 4c représentent, à titre d'exemple, trois exemples de configurations que peut présenter la paroi de réglage d'un circuit magnétique selon l'invention, une fois le réglage de celui-ci effectué. La paroi 5a montrée à la Fig.4a a été percée d'un trou unique 7a dont la diamètre a été calculé pour obtenir au plus juste la valeur prédéterminée de self-inductance. La paroi 5b montrée à la Fig. 4b a été percée d'une succession de trous 7b qui sont identiques et répartis sur une spirale ; une mesure de self-inductance est faite après le perçage de chaque trou 7b pour déterminer s'il y a lieu ou non de percer le trou suivant. La paroi 5c montrée à la Fig. 4c correspond à l'utilisation par l'ordinateur 11 d'un programme qui détermine, après chaque mesure de self-inductance, le diamètre du trou 7c à percer en vue d'approcher par défaut la valeur de self-inductance prédéterminée. On conçoit que les trous 7c ainsi percés, centrés également sur une spirale coplanaire à la paroi de réglage 5c, sont de plus en plus petits. Le procédé de réglage selon la configuration de la Fig. 4c contribue à la fois à une grande rapidité d'exécution et à un réglage très précis.In order to obtain other configurations of the adjustment wall, the computer 11 can control, as a function of different prerecorded programs in the memory 12, the operation of the laser source 14 according to different sequences. Figures 4a, 4b and 4c re present, by way of example, three examples of configurations which the adjustment wall of a magnetic circuit according to the invention can have, once the adjustment thereof has been carried out. The wall 5a shown in FIG. 4a has been pierced with a single hole 7a whose diameter has been calculated to obtain the predetermined self-inductance value as closely as possible. The wall 5b shown in FIG. 4b has been pierced with a succession of holes 7b which are identical and distributed over a spiral; a self-inductance measurement is made after the drilling of each hole 7b to determine whether or not to drill the next hole. The wall 5c shown in FIG. 4c corresponds to the use by the computer 11 of a program which determines, after each self-inductance measurement, the diameter of the hole 7c to be drilled in order to approach by default the predetermined self-inductance value. It will be appreciated that the holes 7c thus drilled, also centered on a coplanar spiral to the adjustment wall 5c, are becoming smaller. The adjustment method according to the configuration of FIG. 4c contributes both to great speed of execution and to very precise adjustment.

A titre d'exemple, en mettant en oeuvre le procédé de réglage selon la Fig. 4c, le réglage automatique de self-inductance est effectué avec une précision de 10'-4 au rythme d'un circuit magnétique par seconde. Un tel circuit magnétique a par exemple une section des noyaux centraux 1 ", 2" de 26 mm2, une section de la cheminée de réglage 3 de 7 mm2 et une épaisseur de la paroi de réglage 5c de 0,3 mm. L'usinage est effectué par un faisceau laser dont l'émission est modulée par des impulsions d'une durée unitaire de 0,5 ps. Chaque impulsion permet une érosion de matière sur une profondeur d'environ 50 µm.By way of example, by implementing the adjustment method according to FIG. 4c, the automatic self-inductance adjustment is performed with a precision of 10 ' -4 at the rate of one magnetic circuit per second. Such a magnetic circuit has for example a section of the central cores 1 ", 2" of 26 mm 2 , a section of the adjustment chimney 3 of 7 mm 2 and a thickness of the adjustment wall 5c of 0.3 mm. The machining is carried out by a laser beam, the emission of which is modulated by pulses with a unit duration of 0.5 ps. Each pulse allows material erosion to a depth of approximately 50 µm.

Selon la réalisation préférée décrite ci-dessus en référence à la Fig. 1 , les demi-coquilles 1 et 2 sont différentes. Il est évident que pour de multiples raisons, entre autres d'économie, on peut associer, pour constituer un circuit magnétique, deux demi-coquilles de structures identique sans pour cela sortir du cadre de la présente invention. Selon ce dernier cas, on règle le circuit magnétique ainsi formé soit simultanément, soit alternativement, par usinage de l'une et/ou l'autre des parois de réglage des demi-coquilles.According to the preferred embodiment described above with reference to FIG. 1, the half-shells 1 and 2 are different. It is obvious that for multiple reasons, among other reasons of economy, it is possible to combine, to constitute a magnetic circuit, two half-shells of identical structures without thereby departing from the scope of the present invention. In the latter case, the magnetic circuit thus formed is adjusted either simultaneously or alternately, by machining one and / or the other of the adjustment walls of the half-shells.

Claims (4)

1 - Circuit magnétique conformé en un pot constitué par la superposition de deux demi-coquilles en ferrite (1, 2) et pourvu d'un entrefer (4) en son noyau central (1" , 2"), caractérisé en ce qu'au moins l'une (2) des deux demi-coquilles qui sont assemblées et immobilisées par collage ou agrafage, comporte au voisinage de l'entrefer (4) une paroi mince (5) dont le percement partiel et graduel (7) augmente graduellement la valeur de la réluctance du circuit magnétique à une valeur prédéterminée.1 - Magnetic circuit shaped as a pot consisting of the superposition of two ferrite half-shells (1, 2) and provided with a gap (4) in its central core (1 ", 2"), characterized in that at least one (2) of the two half-shells which are assembled and immobilized by gluing or stapling, comprises in the vicinity of the air gap (4) a thin wall (5) whose partial and gradual piercing (7) gradually increases the value of the reluctance of the magnetic circuit to a predetermined value. 2 - Procédé de réglage de la réluctance du circuit magnétique en ferrite conforme à la revendication 1, caractérisé en ce qu'on mesure la valeur de 1a réluctance du circuit magnétique à régler, en ce qu'on compare successivement les valeurs de réluctance mesurées à ladite valeur prédéterminée pour déterminer la quantité de matière (7) de la paroi mince (5) qui doit être éliminée et en ce qu'on enlève cette quantité de matière par creusage et perçage d'un ou plusieurs trous (7) au travers de ladite paroi (5).2 - Method for adjusting the reluctance of the ferrite magnetic circuit according to claim 1, characterized in that the value of the reluctance of the magnetic circuit to be adjusted is measured, in that the reluctance values measured are successively compared with said predetermined value for determining the quantity of material (7) of the thin wall (5) which must be removed and in that this quantity of material is removed by digging and drilling one or more holes (7) through said wall (5). 3 - Procédé conforme à la revendication 2, caractérisé en ce que lesdits trous (7) sont obtenus par usinage au moyen d'une source laser (14) dont le faisceau laser (15) a une orientation, une intensité, une durée de fonctionnement et une convergence qui sont déterminées par un calculateur (10, 11, 12) en fonction de la valeur de réluctance prédéterminée pour le circuit magnétique.3 - Method according to claim 2, characterized in that said holes (7) are obtained by machining by means of a laser source (14) whose laser beam (15) has an orientation, an intensity, an operating time and a convergence which are determined by a computer (10, 11, 12) according to the predetermined reluctance value for the magnetic circuit. 4 - Procédé conforme à la revendication 2 ou 3, caractérisé en ce que la mesure de la valeur de la réluctance du circuit magnétique consiste en une mesure de self-inductance ou de fréquence effectuée sur l'inductance ou le transformateur constitué à partir dudit circuit magnétique, cette inductance ou ce transformateur étant interconnecté dans un circuit électronique en fonctionnement normal.4 - Process according to claim 2 or 3, characterized in that the measurement of the reluctance value of the magnetic circuit consists of a self-inductance or frequency measurement carried out on the inductance or the transformer formed from said circuit magnetic, this inductor or transformer being interconnected in an electronic circuit in normal operation.
EP19790400217 1978-04-06 1979-04-03 Inductance with a ferrite pot core and method to adjust the reluctance of the core Expired EP0005386B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR7810188 1978-04-06
FR7810188A FR2422235A1 (en) 1978-04-06 1978-04-06 NEW MAGNETIC FERRITE CIRCUIT AND METHOD FOR ADJUSTING THIS CIRCUIT

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EP0005386A1 true EP0005386A1 (en) 1979-11-14
EP0005386B1 EP0005386B1 (en) 1981-09-02

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EP19790400217 Expired EP0005386B1 (en) 1978-04-06 1979-04-03 Inductance with a ferrite pot core and method to adjust the reluctance of the core

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EP (1) EP0005386B1 (en)
JP (1) JPS54136654A (en)
CA (1) CA1120998A (en)
DE (1) DE2960720D1 (en)
ES (1) ES479328A1 (en)
FR (1) FR2422235A1 (en)
YU (1) YU81379A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1540675A1 (en) * 2002-09-17 2005-06-15 Pulse Engineering, Inc. Controlled inductance device and method
EP2597656A4 (en) * 2010-07-21 2015-06-17 Kobe Steel Ltd Reactor

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4424504A (en) * 1981-06-19 1984-01-03 Tdk Electronics Co., Ltd. Ferrite core

Citations (5)

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Publication number Priority date Publication date Assignee Title
DE1208425B (en) * 1959-01-14 1966-01-05 Int Standard Electric Corp Procedure for the inductivity adjustment of ferrite pot core coils
FR1523460A (en) * 1967-03-24 1968-05-03 Lignes Telegraph Telephon Adjustable Inductance Ferromagnetic Core Coil
FR1586479A (en) * 1967-09-29 1970-02-20
US3670406A (en) * 1970-02-04 1972-06-20 Texas Instruments Inc Method of adjusting inductive devices
FR2330202A1 (en) * 1975-10-27 1977-05-27 Siemens Ag LC TYPE ELECTRIC OSCILLATING CIRCUIT

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Publication number Priority date Publication date Assignee Title
DE1208425B (en) * 1959-01-14 1966-01-05 Int Standard Electric Corp Procedure for the inductivity adjustment of ferrite pot core coils
FR1523460A (en) * 1967-03-24 1968-05-03 Lignes Telegraph Telephon Adjustable Inductance Ferromagnetic Core Coil
FR1586479A (en) * 1967-09-29 1970-02-20
US3670406A (en) * 1970-02-04 1972-06-20 Texas Instruments Inc Method of adjusting inductive devices
FR2330202A1 (en) * 1975-10-27 1977-05-27 Siemens Ag LC TYPE ELECTRIC OSCILLATING CIRCUIT

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Title
THE TRANSACTIONS OF THE IECE OF JAPAN, Vol. E60, No. 11, Novembre 1977 Tokyo (JP) A. IWATA: "Laser functional trimming for hybrid integrated RC active filters", pages 667-668 * la totalite de l'article * *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1540675A1 (en) * 2002-09-17 2005-06-15 Pulse Engineering, Inc. Controlled inductance device and method
EP1540675A4 (en) * 2002-09-17 2009-11-11 Pulse Eng Inc Controlled inductance device and method
EP2597656A4 (en) * 2010-07-21 2015-06-17 Kobe Steel Ltd Reactor

Also Published As

Publication number Publication date
FR2422235A1 (en) 1979-11-02
EP0005386B1 (en) 1981-09-02
CA1120998A (en) 1982-03-30
FR2422235B1 (en) 1981-09-11
ES479328A1 (en) 1979-12-16
YU81379A (en) 1983-04-30
DE2960720D1 (en) 1981-11-26
JPS54136654A (en) 1979-10-23

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