FR2731833A1 - Induction coil for use in magneto-forming equipment - Google Patents

Abstract

The induction coil comprises two parts (8,9) which may be symmetrical, extending parallel to an axis (10). This axis forms the longitudinal axis of a cylindrical aperture through the centre of the coil where a magnetic field is generated by the effect of a large current flowing in the coils turns of the induction coil. The coil is separated into two parts by a diametrical line, so that they may be moved apart to give access to the intervening space. Each part consists of half-turns of a support, such as a synthetic resin material, on which a conductor is formed. Each part has two end contacts (18a) allowing current to be driven through the half-turns. The current flow has the same rotational direction in the two parts, thus giving rise to a combined axial magnetic field within the cylindrical space.

Description

DEFORMABLE INDUCTION COIL FOR A MAGNETOFORMING DEVICE
The present invention relates to a deformable coil or inductor, that is to say having at least two moving parts relative to each other, which coil is intended to enter the composition of a magnetoforming device.

 The technical field of the invention is that of the manufacture of magnetoforming devices.

 Patent FR2 488 163 (Center Stéphanois de Recherche Mécanique Hydromécanique et Frottement) already known from a magnetotorming coil whose conductor and carcass are arranged in several parts to be open and / or deformable so as to be adapted or removed. around the pieces to be magnetized.

 According to this document. the electrical connection between the coil parts can be effected by a solid conductive element, a fluid conductive element (liquid or gas).

 A magnetotroping coil in at least two parts makes it possible to extract the reel (or parts) from the reel after its deformation by magnetoforming (and / or their assembly by magnetoforming).

 The object of the present invention is to provide an improved two-part separable coil.

 Indeed. in the separable coil of the evoked document, when the conductive element is in fluid form (liquid or plasma), sealing means are to be provided which lead to a complex design of such a coil 1, moreover, the different embodiments of solid electrical connections between the coil parts such as plug-in plugs. nc not allow to guarantee a very good conduction between the different parts of the coil which is a particular disadvantage for the magnetoforming coils which by nature are intended to be traversed by a current of very high intensity.

 The present invention aims to provide a multi-part induction coil for a magnetoforming device whose design and construction are very simple and which allows satisfactory operation. that is to say to allow the passage of an electric current in the turns of the coil having a very high intensity.

 The present invention also aims to provide such a coil whose service life is sufficient to allow several hundreds of thousands of magnetic forming operations.

 The solution to the problem posed consists in providing an induction coil in at least two parts for a magnetoforming device in which each part (separable or mobile) of said coil comprises respective connection means for connecting or connecting in series the parts or successive coil element of said coil portion.

 In other words, the invention provides an induction coil for magnetoforming. separable into at least two movable parts relative to each other, comprising a first coil portion having a plurality of first parts or juxtaposed elements of coil. and comprising a second coil portion having a plurality of second or juxtaposed coil portions, wherein said first coil portions are connected in series to form a first electrically conductive assembly (substantially indeformable) and wherein said second portions or coil members are connected in series to form a second electrically conductive assembly (which can be indefinitely), which first and second conductive assemblies are connected (in series or in parallel) to a source (preferably a common source) of electrical power.

According to a preferred embodiment of the invention, the invention provides an induction coil having a plurality of coil elements or plates of electrically conductive material. substantially rigid, each of said turn elements constituting a turn portion of said coil. which coil preferably comprises an even number of said coil elements which are for example identical, each coil element comprising ::
- A first portion in the form of curved arcuate arch, preferably in the form of part or crown section. for example in the form of a half-crown, which first portion in the form of an arch has a first end or upstream end and a second end or downstream end,
a second portion constituting an elongate upstream (or shaped) arm having a first end or upstream end and having a second end or downstream end which is connected (or fixed or connected) to said upstream end of said first part; arch form.

a third portion constituting an elongate downstream (or shaped) arm having a first end or upstream end which is connected (or fixed or connected) to said second end or downstream end of said first arch-shaped portion, and having a second end or a downstream end,
which coil comprises for each pair of said coil elements or plates (constituted by two adjacent coil elements or plates and parallel to each other), electrical connection means of said downstream end of said downstream arm of a first coil element of said pair and said upstream end of said upstream arm of a second coil element (or wafer) of said pair.

 For the purposes of this application. the terms * upstream and downstream are used by reference to the direction of flow of electric current in the parts of the coil.

The invention also provides a method of manufacturing an induction coil in at least two parts for a magnetoforming device in which
- cut. for example by stamping. identical plates, for example rectangular in a strip of an electrically conductive material such as copper,
for example, by cutting and / or stamping a first portion of said wafer which is located along a first edge of said wafer and which is in the form of a portion of a disk is removed.

 for example, a second portion of said wafer (which is delimited for example by two preferably concentric circular edges, which circular edges are joined at their ends by connection end lines or edges) is removed for example by cutting and / or stamping; . so as to arrange in said plate an opening (or light).

 - Cutting along a line preferably extending along an axis of symmetry of said wafer. the portion of said wafer located between a second edge opposite said first edge of said wafer and said light obtained according to the above operation.

According to preferred embodiments of coil according to the invention
the junction faces or mechanical joining of the moving coil parts are located in radial or diametrical separation planes
the electrically conductive parts each consist of a stack of coil elements. that is to say consisting of juxtaposed plates, ie wafers or coil elements whose main faces are placed opposite and separated by an insulating element, each of said wafers or coil elements being provided with two connection ends which are folded and / or curved ::
- The electrically conductive parts of the coil are each constituted by a coil element stack. each turn element having a first central portion or portion in the form of a corner crown segment at the center preferably close to 180- (to 30) and of substantially constant section ;;
the electrically conductive parts each consist of a stack of coil elements. each coil element or plate having a second or upstream arm and a third or downstream arm of non-uniform section (or width)
the section of said upstream and downstream arms increases from a minimum section corresponding to a zone of said arm near the end of said first arch-shaped portion;
said elements of turns are made of copper
the first part of each of the turn elements has a square or rectangular section.

 The many advantages provided by the invention will be better understood from the following description which refers to the accompanying drawings, which illustrate without any limiting character a preferred embodiment of an induction coil according to the invention.

 Figures 1 and 2 schematically illustrate in perspective view of the wafers or coil coil elements of the invention.

 3 schematically illustrates in perspective view an induction coil equipped with platelets according to the invention.

 Figures 4 and 5 respectively show a plan view and elevation view, a second embodiment of wafer or coil element for induction coil according to the invention.

 FIG. 6 illustrates the section of the central part of a turn element according to the invention.

 Figure 7 schematically illustrates the operations of a wafer manufacturing method or coil element according to the invention.

 With reference to FIGS. 1 to 3, induction coil 1 according to the invention consists of at least two parts 8 and 9, for example symmetrical, which extend parallel to an axis 10 constituting the longitudinal axis of a central housing. 13 cylindrical for receiving parts to form or deform under the effect of a magnetic field produced by a current of high intensity flowing in the turns of the induction coil.

 In the embodiment shown in Figures 1 to 3, the two parts 8 and 9 of the coil are separated by a diametral separation plane 11 although it may be otherwise.

 In that case. the parts 8 and 9 of the coil are substantially identical, and the plates or coil elements 12a. 12b. 12c. 12d of Figures 1 and 2 are also identical.

 The plates 12 constituting each portion 8 and 9 of the coil 1 are separated by plates or electrically insulating element shown schematically (reference 14 Figure 1) and for example made by embedding the dcmi-turns in a material (eg synthetic resin) appropriate .

 As illustrated in FIGS. 1 to 3, two successive half-turns of a stack of half turns about an axis parallel to the main axis (reference 10 FIG. 3) of the coil are electrically connected by connection means 15 of any type. known (solder, solder, mechanical connection).

 More particularly. with reference to FIG. 2, it can be seen that a turn element 12c essentially consists of a first part or central portion 6 extending substantially along a circular half-crown. whose upstream end 16 is in connection with the corresponding end 18b downstream of an upstream arm 18 whose free (or upstream) end 18a can be connected to the positive pole of a power supply source ( figure 1).

 The end 17 of the central portion 6 of the wafer 12c is itself connected to the upstream end 19a of a second arm 19 (downstream arm) whose second end or free end (or downstream) t9b is connected by means electrical connection 15 to the upstream end 18a of an upstream arm 18 of the wafer 12d which is juxtaposed with the wafer 12c.

 The other end 19b of this wafer 12d is connected (as illustrated in FIG. 1) to the negative terminal of a power supply source, so that the wafers 12c and 12d of the lower stack of the coil are connected. serial.

 Thanks to this particular embodiment and connection of the two half-turns 12c and 12d, the current delivered by the power supply source circulates in said demispires 12c, 12d as schematically represented by arrows in FIG. 1.

 An identical and substantially symmetrical embodiment is provided in the second part 8 of the coil consisting for example of the two wafers or half-turns 12a and 12b connected together by connecting means 15a, 15b and also connected to the positive and negative terminals dc. same power source as shown in Figure 1 so as to allow the passage of electric current during the power supply according to the arrows in this figure.

 This is done in the space or housing cylindrical located between the central parts 4,5. 6, 7 of the two half-turns 12a and 12h on the one hand and 12b and 12d on the other hand, a magnetic field caused by a flow of electric current in the central portions of the wafers. corresponding (similar or identical) to the magnetic field created by the usual circulation of electric current in two complete turns; the plates 12a and 12c are substantially flat and extend in the same plane and the ends 16, 17 of the respective central portions 4 and 6 of these plates are close to one another respectively to reproduce substantially in the two half 12a and 12c a magnetic field configuration caused by the passage of electric current similar to that prox oque by a usual continuous coil.

 With reference to FIGS. 4 and 5, it can be seen that a wafer constituting a half-turn 12 forming part of a coil according to the invention may be provided with a generally curved shape 30 and obtained according to a method according to FIG. invention from cuts or stampings made in a copper plate.

It can be seen that the central portion or first portion 4 of the wafer 12 extends substantially in the form of a ring. of substantially constant thickness 24, of preferably square or rectangular cross-section as illustrated in FIG. 6, the inner edge 20 of the central element 4 extending substantially along a cylinder of radius 21 with a longitudinal axis (perpendicular to the plane of FIG. A) passing through the center 22 marked FIG. 4, which central portion 4 extends along a half-crown or a portion of a corner ring at the center 31, for example close to 180-
The ends of the central portion 4 are connected to the arms (or second and third respective portions) 18 and 19 of said wafer 12, the width of which is shown in FIG. 4 (or the corresponding section of the arms) varies by a minimum section or width in a zone of the arms located near the central part 4, to larger values such as represented in particular by the reference 26. reccérant the width of a central portion of the arm 19.

 The plate of FIG. 4 is preferably substantially symmetrical relative to the axis 33 containing said center 22 of the circle of radius 21 along which the inner edge 20 of the central portion A extends.

 Beyond this central portion extends a window or light 27 obtained by cutting as explained below with reference to FIG.

 The inner edge 20 of the central portion 4 illustrated in FIG. 4 is obtained for example by stamping and then by milling or grinding in order to obtain a good precision on the profile of this inner face intended to delimit the cylindrical housing marked 13 in FIG. 3; likewise the bearing faces 23 of the half-turns between them can also be machined with precision in order to obtain a geometry of high precision for all of said turns and consequently of the coil.

 The parts 18 and 19 forming connection arms of the central portion of the wafer 12 are separated by a cutout 28 (extending for example along the axis 33 of symmetry of the wafer) also shown in FIG. 7.

 With reference to FIG. 5, it can be seen that the wafer 12 of generally flat shape (of thickness 29, for example a few millimeters) comprises arms 18 and 19 whose ends 18a and 19b are curved and bent to be prominent on the one hand. and other faces of said plate 12 for connection with the corresponding ends of the wafer which will be juxtaposed with that shown in Figure 5.

 Referring to Figure 7, a wafer 12 may be obtained by cutting in a copper strip for example according to a rectangular profile whose two edges of greater length 34. 42 face each other (are two opposite edges of the rectangle).

 A first portion 37 of the wafer 12 may be cut by stamping for example according to a circular profile extending along a radius 21 and a center 22 located in the immediate vicinity of the edge 34 or on it.

 A second part 3 (S of the plate 12 can be cut to obtain the opening or the light marked 27 in FIG. 4 by cutting or drawing according to a closed profile comprising a circular line 39 of radius 35 centered on said center 22, a second circular profile A () of radius 3f) greater than the radius 35 (which itself is greater than the radius 22) and also centered on the center 22. Which edges or profiles 39 and 40 of the blank 38 are connected by lines 41 for example curves.

 The portion of the wafer 12 located between the portion 38 cut to form the light 27 and the edge 42 opposite the edge 34 is then cut along the substantially rectilinear profile 28 to delimit the edges 18a and 19b of the connecting arms of the wafer as well as represented in FIG.

Claims (10)

 1. Two-part induction coil (1) (8, 9) for a magnetoforming device. characterized in that each portion (8 9) has respective connecting means (15) for serially connecting the turn portions (4,5), respectively (6,7), of said coil portion.  2. Induction coil (1) for magnetoforming, separable into at least two movable parts relative to each other, comprising a first coil portion (8) having a plurality of first portions (4, 5) or elements juxtaposed coil, and comprising a second portion (9) coil having a plurality of second parts (6,7) or juxtaposed elements of turn. characterized in that said first turn portions (4, 5) are connected in series to form a first electrically conductive assembly, and in that said second portions (6, 7) or coil members are connected in series to form a second electrically conductive assembly, which first and second conductive assemblies are connected to a common power source.  Induction coil (1) for a magnetoforming device comprising a plurality of coil elements or plates (12) of electrically conductive material, each of said coil elements constituting a part of turn of said coil, each coil element comprising  a first arcuate shaped arcuate portion (4. 5. 6, 7) having a first end (16) or an upstream end and a second end (17) or a downstream end,  a second portion constituting an elongate upstream arm (18) having a first end (18a) or upstream end and having a second end (18b) or downstream end which is connected to said upstream end (16) of said first shaped portion; ark.  which coil comprises. for each pair (12c, 12d), respectively (12a, 12b) of said adjacent coil elements or wafers. means (15) for electrical connection of said downstream end of said downstream arm of a coil element (12c), respectively (12a), and said upstream end of said upstream arm of the coil element or plate (12d) respectively (12b).  a third portion constituting an elongated downstream arm (19) having a first end (19a) or upstream end which is bonded to said downstream end (17) of said first arch portion, and having a second end (19b) or downstream end,  4. Coil according to any one of claims 1 to 3, the electrically conductive parts each consist of a stack of coil elements, or plates (12) juxtaposed. and separated by an insulating member (14), each of said wafers or turn elements being provided with two connecting ends (18a, 19b).  5. Coil according to any one of claims 1 to 4, the electrically conductive parts each consist of a stack of coil elements, each having a central portion (4 * 5. 6. 7) in the form of a section of crowned.  6. Coil according to any one of claims 1 to 5, the electrically conductive portions each consist of a stack of turn elements, each having an upstream arm (18) and a downstream arm (19) section (25). , 26) non-uniform.  7. A coil according to any one of claims 3 to 6 wherein the section (25,26) of said upstream and downstream arms (18. 19) increases from a minimum section (25) corresponding to a zone of said arm (18. 19) close to the end of said first arch-shaped portion (4).  8. Coil according to any one of claims 1 to 7 wherein said coil elements are copper.  9. A coil according to any one of claims 3 to 8 wherein said first portion (4. 5. 6. 7) of each of the coil elements has a square or rectangular cross-section.  10. A method of manufacturing an induction coil in at least two parts for a magnetoforming device in which  we cut. identical plates (12). in a strip of an electrically conductive material such as cuix rc.  removing a second portion (38) of said wafer so as to provide in said wafer an opening or light (27).  removing a first portion (37) of said wafer which is located along a first edge (34) of said wafer and which is in the form of a portion of disk,  the portion of said wafer located between a second edge (42) opposite to said first edge (34) of said wafer and said light (27) obtained according to the above operation is cut along a line (28).