JP2009054808A - Coil for pulse magnetic forming and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a long-lived coil for pulse magnetic forming which suppresses the occurrence of a gap during impregnation with resin, and to provide its manufacturing method. <P>SOLUTION: A peripheral surface of a shaft portion of a bobbin 2 made of an insulator is wound with a resin-permeable glass cloth tape 3 to a predetermined thickness. A conductor strand 4 coated with a glass cloth tape 6 is wound outside it spirally along the axis of the bobbin 2 to constituted a coil. The conductor strand 4 is wound so that mutually opposed surfaces of adjacent portions of the conductor strand 4 are parallel to each other. A glass cloth 7 after being wound outside it to a predetermined thickness is impregnated with resin 8 to unite together the conductor strand 4 and an insulating layer at its periphery. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electromagnetic forming coil used when electromagnetically forming a metal tube or the like and a manufacturing method thereof.

  Electromagnetic forming in which metal is plastically processed using electromagnetic force can be flexibly adapted to various shapes such as a plate shape and a tubular shape, and therefore, application to various fields is being studied. In this electromagnetic forming, the electric charge stored at a high voltage is instantaneously discharged to the coil for electromagnetic forming to form a strong magnetic field in a very short time around it, and the work piece is placed in this magnetic field. Thus, a repulsive force is generated between the workpiece and the forming coil to form and process the workpiece.

  As an electromagnetic forming coil used for such electromagnetic forming, for example, one disclosed in Patent Document 1 or 2 is known. FIG. 3 is a cross-sectional view showing a conventional coil for electromagnetic forming according to the techniques described in Patent Documents 1 and 2. FIG. 3 is an enlarged view of a portion of the electromagnetic forming coil in which a conducting wire is wound around a bobbin that is an axial center.

  As shown in FIG. 3, the electromagnetic forming coil 101 has a bobbin 2 configured in an axial shape with an insulating resin. A hollow conductor element wire 4 having a rectangular cross section covered with a glass cloth tape 6 is wound around the bobbin 2 in a spiral shape with the bobbin 2 as an axis to form a coil. In addition, this conductor strand 4 is wound so that the surface where the adjacent conductor strand 4 opposes may become parallel. A glass cloth 7 is wound around the outside so as to have a predetermined thickness. The insulating resin 8 is impregnated in the gap between the glass cloth tape 6, the glass cloth 7, and each component, thereby fixing the insulating layer and the conductor. The electromagnetic forming coil 101 has a predetermined outer diameter by cutting the outer periphery of the glass cloth 7 after the resin 8 is impregnated.

Japanese Patent Laid-Open No. 2004-40044 Japanese Patent Laid-Open No. 06-238356

  However, the conventional techniques described above have the following problems. In the electromagnetic forming coil 101 shown in FIG. 3, the resin 8 is impregnated along the fiber of the glass cloth at the time of impregnation, and does not penetrate into the resin of the bobbin 2 itself. For this reason, the portion immediately above the bobbin at the boundary between the glass cloth tapes 6 covering the respective conductors (B portion shown in FIG. 3) tends to have insufficient resin penetration, and as a result, voids are likely to occur. On the other hand, when the electromagnetic forming coil 101 is used, the conductor wire 4 vibrates when a large current is applied to the coil. Therefore, if there is a gap inside the electromagnetic forming coil 101, that portion becomes a source of cracks. Cheap. The cracks that have developed may develop due to repeated use and eventually cause deformation and breakage of the electromagnetic forming coil 101. Therefore, the life of the electromagnetic forming coil having a gap inside is shortened.

  This invention is made | formed in view of this problem, Comprising: It suppresses generation | occurrence | production of the space | gap at the time of impregnating resin, and it aims at providing the coil for electromagnetic forming with a long lifetime.

  An electromagnetic forming coil according to the present invention includes a shaft portion, a center side fiber layer having resin impregnation property and covering a peripheral surface of the shaft portion, and a conductor having a resin impregnation property covering the center side fiber layer. Coil constituted by winding on a peripheral surface, outer fiber layer having resin impregnation property and covering the outer periphery of the coil, and insulating impregnation impregnated and cured in each component having resin impregnation property And a resin. The shaft portion includes not only a columnar shape but also a cylindrical shape, for example.

  In this case, the center side fiber layer can be composed of glass cloth tape.

  The electromagnetic forming coil manufacturing method according to the present invention includes a step of covering the peripheral surface of the shaft portion with a resin-impregnated center side fiber layer, and a conductive wire having a resin-impregnated coating around the center-side fiber layer. A step of forming a coil by winding on a surface, a step of covering the outer periphery of the coil with an outer fiber layer having a resin impregnation property, and an impregnating resin having an insulating property on each component having the resin impregnation property It has a step of impregnating and a step of curing the impregnating resin.

  According to the present invention, since the center side fiber layer having resin impregnation property is disposed between the coating of the conductive wire and the shaft portion, when the resin is impregnated, for example, the boundary between components such as the periphery of the conductive wire In this case, the resin is sufficiently impregnated, and the generation of voids that are the starting points of cracks is suppressed. As a result, a long-life electromagnetic forming coil can be obtained.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing an electromagnetic forming coil according to the present embodiment. FIG. 1 is an enlarged view of a part of a portion of a coil for electromagnetic forming where a conducting wire is wound around a bobbin that is an axis.

  As shown in FIG. 1, the electromagnetic forming coil 1 of the present embodiment has a bobbin 2 configured in a shaft shape (hereinafter, unless otherwise specified, the shaft or the bobbin 2 is the axis of the bobbin 2). Part). The bobbin 2 is made of, for example, an insulating resin. The bobbin 2 may have, for example, a flange portion for fixing to the outside in addition to the shaft portion shown in FIG. In addition, in this specification, it is displayed as an axial shape, but may be configured as a cylindrical shape, for example.

  A glass cloth tape 3 is wound around the peripheral surface of the shaft portion of the bobbin 2 so as to have a predetermined thickness. The glass cloth tape 3 is made by weaving glass fibers in a tape shape, and has resin impregnation properties with respect to the resin 8 described later. In addition, in this embodiment, it has resin impregnation property similarly about any glass cloth other than the glass cloth tape 3, and a glass cloth tape. However, it is sufficient that at least the glass cloth tape 6 and the glass cloth 7 described later have resin impregnation properties.

  The conductor wire 4 has a rectangular cross section, has a hollow shape with a circular coolant circulation hole formed in the center, and is coated with a glass cloth tape 6 on the outer surface. Then, a hollow conductor element wire 4 is spirally wound around the bobbin 2 around which the glass cloth tape 3 is wound to form a coil. In this case, the adjacent conductor strands 4 are closely wound so that the opposing surfaces are parallel to each other and the glass cloth tapes 6 are in contact with each other. The conductor wire 4 is made of, for example, copper or a copper alloy, and is connected to a power supply device (not shown) to be fed. Further, a liquid or gaseous refrigerant is circulated and supplied from the refrigerant device into the hollow interior of the conductor wire 4 to cool the heat generated during use as a coil.

  A glass cloth 7 is wound around the outer periphery of the coil (that is, on the outer surface of the conductor wire 4) so as to have a predetermined thickness. The glass cloth 7 is in the form of a sheet, but may be in the form of a tape, for example. The insulating resin 8 is impregnated in the gap between the glass cloth tape 3, the glass cloth tape 6, the glass cloth 7, and each component and then cured. Thereby, the insulating layer and the conductor are firmly fixed. As the resin 8, for example, an epoxy resin having thermosetting properties can be used. The shaft portion of the electromagnetic forming coil 1 has a predetermined outer diameter by cutting the outer peripheral surface of the glass cloth 7 after impregnation with the resin 8.

  Hereinafter, the manufacturing method of the coil for electromagnetic forming of this embodiment is demonstrated. The electromagnetic forming coil 1 of this embodiment shown in FIG. 1 can be manufactured by the method shown below, for example. First, the glass cloth tape 3 is wound around the peripheral surface of the bobbin 2. At this time, the glass cloth tapes 3 are partially wrapped. In the present embodiment, for example, as shown in FIG. Thus, by winding the glass cloth tape 3 with a half wrap, the deviation of the tape, the deviation of the insulating thickness, and the like can be suppressed. In FIG. 2, the number of turns of the glass cloth tape 3 is shown as one for convenience, but the number of turns may be plural so that the layer of the glass cloth tape 3 has a predetermined thickness.

  Next, a coil is formed by winding the conductor wire 4 covered with the glass cloth tape 6 around the outer periphery of the glass cloth tape 3 in a spiral shape. At this time, the winding is performed such that adjacent surfaces of the adjacent conductor wires 4 are parallel to each other.

  Next, after winding the glass cloth 7 around the outer periphery of the coil, the resin 8 is impregnated. As the resin 8, for example, an epoxy resin having insulating properties and thermosetting properties is used. Thereafter, the insulating layer is firmly fixed by heating and curing the resin 8. Thereafter, by cutting the outer peripheral surface of the glass cloth 7 with the bobbin 2 as an axis, the electromagnetic forming coil 1 having a predetermined outer diameter is obtained.

  Next, the operation of this embodiment will be described. For example, when the electromagnetic forming coil 1 of this embodiment shown in FIG. 1 is used for expanding a metal tube, first, the shaft portion of the illustrated electromagnetic forming coil 1 is a metal tube (not shown) as a workpiece. N) Insert in. Next, a large impact current is applied to the coil constituted by the conductor wires 4 to generate a magnetic field around the shaft portion of the electromagnetic forming coil 1. Accordingly, the metal tube is expanded by receiving a strong expansion force toward the outside due to the repulsive force of the magnetic field, and is pressed against a forming die (not shown) disposed outside the metal tube. In addition, in order to cool the heat | fever which generate | occur | produces in the conductor strand 4 at this time, the refrigerant | coolant has distribute | circulated through the hollow part of the conductor strand 4. FIG.

  In the present embodiment, the impregnated resin 8 penetrates to the glass cloth tape 3 on the axial center side of the glass cloth tape 6 covering the conductor wire 4. Accordingly, the resin 8 can be sufficiently infiltrated even at the boundary portion between the adjacent glass cloth tape 6 and other components such as the portion A shown in FIG. 1, and as a result, the generation of internal voids is extremely small. can do.

  As described above, in this embodiment, since the generation of voids in the impregnating resin is extremely reduced, the periphery of each conductor is firmly fixed. In other words, cracks starting from the voids are less likely to occur inside the insulating layer. As described above, when the electromagnetic forming coil 1 is used, a large current is passed through the coil. However, according to the present embodiment, the possibility of damaging the electromagnetic forming coil is extremely reduced according to the present embodiment even after repeated use. . As a result, the life of the electromagnetic forming coil can be dramatically extended.

  In this embodiment, an insulating resin is used as the bobbin 2. Technical requirements for the material of the bobbin 2 include, for example, high insulation, high strength, high cutting workability, affinity with the outer surface impregnating resin, and the like. Here, according to the present embodiment, since the resin 8 is impregnated on the entire surface of the conductor and firmly fixed, various materials can be used as the resin used for the bobbin 2. For example, in this embodiment, since the integrity of the conductor wire 4 and the surrounding impregnation layer (glass cloth tape 3, glass cloth tape 6, glass cloth 7, and resin 8) is high, the bobbin 2 is made of an outer surface impregnating resin. A material having a slightly low affinity may be used. Therefore, a low cost material can be used for the bobbin 2. Further, depending on the use conditions of the electromagnetic forming coil, it is possible to make the electromagnetic forming coil bobbinless and to be constituted by the conductor element wire 4 and the surrounding impregnation layer.

  Moreover, in this embodiment, although the conductor strand 4 has a rectangular cross section, this invention is not limited to this. As shown in FIG. 1, the present invention is suitable for a conductor wire having a rectangular cross section in which a minute gap is easily formed between two adjacent conductor wires 4 and the bobbin 2 side. Even when the strand has a circular cross section, the impregnation property of the contact portion with the bobbin side is improved, and good integrity can be obtained, which is effective.

It is sectional drawing which shows the coil for electromagnetic forming which concerns on embodiment of this invention. It is sectional drawing which shows the glass cloth tape wound around the surrounding surface of the bobbin in the coil for electromagnetic forming which concerns on embodiment of this invention. It is sectional drawing which shows the conventional coil for electromagnetic forming.

Explanation of symbols

1; Electromagnetic forming coil 2; Bobbin 3; Glass cloth tape 4; Conductor 6; Glass cloth tape 7; Glass cloth 8; Resin 101;

Claims (3)

It is configured by winding a shaft portion, a center side fiber layer having resin impregnation property and covering the peripheral surface of the shaft portion, and a conductive wire having a resin impregnation coating around the peripheral surface of the center side fiber layer. A coil, an outer fiber layer having resin impregnation property and covering an outer periphery of the coil, and an insulating impregnating resin impregnated and cured in each component having the resin impregnation property. Electromagnetic forming coil. The coil for electromagnetic forming according to claim 1, wherein the center side fiber layer is made of glass cloth tape. A step of coating the peripheral surface of the shaft portion with a center-side fiber layer having resin impregnation, and a step of forming a coil by winding a conductive wire having a resin-impregnation coating around the peripheral surface of the center-side fiber layer; A step of coating the outer periphery of the coil with an outer fiber layer having resin impregnation properties, a step of impregnating each constituent having resin impregnation properties with an impregnation resin having insulation properties, and a step of curing the impregnation resin. The manufacturing method of the coil for electromagnetic forming characterized by having these.

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