JP2006068775A - Coil for electromagnetic tube expansion forming - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coil for electromagnetic tube expansion forming, which coil hardly fractures even when the coil has been repeatedly used. <P>SOLUTION: After a flange portion 3 has been formed so as to be integral with an axis, a rod portion 2 is formed by winding a conductive wire 4 around the axis of the rod portion 2. Then, the flange portion 3 is sandwiched between grip plates 6, 7 having holes 8, 9 respectively in the direction of the axis, the holes 8, 9 being formed therein so as to be fitted on the flange portion 3, and the grip plates 6, 7 are fixed to each other by means of screws 10. Then, the coil 1 for electromagnetic tube expansion forming is fixed to a mounting stand 13 by fixing the grip plates 6, 7 to the mounting stand 13 by screwing the screws 10 into threaded holes 14 provided on the mounting stand 13. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coil for electromagnetic tube expansion used when electromagnetic tube expansion molding of a metal tube or the like.

  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 mold and process the workpiece (for example, see Patent Document 1). Patent Document 1 discloses a method of forming a caulking fitting portion on a metal tube by electromagnetic tube expansion molding.

  Generally, a forming coil used for electromagnetic forming has a conductive wire wound around a shaft made of an insulating resin. However, a conventional electromagnetic forming coil having such a structure is generated by repeatedly applying a large current. Deformation and breakage may occur due to heat generated from the conductor due to vibration and resistance. Therefore, conventionally, an electromagnetic forming coil has been proposed in which the winding state of the conducting wire is devised to improve durability (see Patent Document 2). The electromagnetic forming coil described in Patent Document 2 reduces the electromagnetic force acting between the conductors by winding the conductors at both ends of the shaft more sparsely than the central part. There has also been proposed an electromagnetic forming coil in which a conductive wire wound around a shaft has a hollow structure and a coolant is circulated through the hollow portion of the conductive wire to prevent temperature rise and improve durability (patent) Reference 3).

  Moreover, in such an electromagnetic tube expansion coil, it is difficult to enlarge the flange portion because the flange portion and the shaft core around which the conducting wire is wound are integrally manufactured by cutting a resin material by machining. . If the flange portion is made large enough to be directly fixed to the installation base, the amount of cutting increases and the material cost increases. For this reason, in the conventional coil for electromagnetic tube forming, a fixing plate is attached to the flange portion, and this fixing plate is fixed to the installation base. 3 and 4 are cross-sectional views schematically showing a conventional electromagnetic tube forming coil. In the conventional coil for forming an electromagnetic tube 51 shown in FIG. 3, a fixing plate 56 provided with a hole 56a through which a terminal portion 55 is inserted is bonded to a flange portion 53 formed at a proximal end portion of a shaft portion 52. Yes. The electromagnetic pipe forming coil 51 is fixed to the installation table 57 by fixing the fixing plate 56 to the installation table 57 with screws 57.

  Further, as shown in FIG. 4, the flange portion 63 formed at the base end portion of the shaft portion 62 is sandwiched between two fixing plates 66 and 67, and the fixing plates 66 and 67 are bonded to each other with an adhesive or the like. There is also an electromagnetic pipe forming coil 61 having a structure. The electromagnetic pipe forming coil 61 is fixed to the installation table 69 by fixing the fixing plate 67 to the installation table 69 with screws 68. In this way, by holding the flange portion 63 between the two fixing plates 66 and 67, the shaft portion 62 that receives vibration repeatedly in the axial direction and the circumferential direction is held in a well-balanced manner so that stress due to vibration does not concentrate. And the periphery of the terminal portion 65 can be reinforced.

JP-A-6-31226 JP-A-55-42140 JP-A-6-238356

  However, the conventional techniques described above have the following problems. That is, the electromagnetic forming coils described in Patent Documents 2 and 3 have a problem that the durability of the central portion and the distal end portion is improved, but the proximal end portion is not effective. For this reason, even if the forming coil is securely fixed to another member, if the forming coil is repeatedly subjected to a large stress, the base end portion may be cracked and damaged.

  Further, the coil 51 for electromagnetic tube expansion forming shown in FIG. 3 is such that the flange portion 53 and the fixing plate 56 are only fixed by screws 59, an adhesive or the like. This causes a problem that the flange portion 53 and the fixing plate 55 are separated. Furthermore, the electromagnetic tube-forming coil 61 shown in FIG. 4 has a problem that since the fixing plates 66 and 67 are bonded to each other, cracks are generated from these bonded surfaces and cannot be used repeatedly. . In particular, in the case of a molded coil used for electromagnetic tube expansion molding, a work material is disposed around the molding coil, so that a space that can be used for reinforcement is limited, and it is difficult to improve strength.

  The present invention has been made in view of such problems, and an object of the present invention is to provide an electromagnetic tube-forming coil that is not easily damaged even when used repeatedly.

  The coil for electromagnetic tube expansion forming according to the first invention of the present application includes a shaft core, a conductive wire wound around the shaft core, a flange portion integrally formed with the shaft core at a base end portion of the shaft core, It has at least two plate-like members that sandwich the flange portion in the axial direction of the shaft core, and a fixing member that fixes the plate-like members to each other.

  In the present invention, since the shaft core and the flange portion are integrally formed, the base end portion is unlikely to be damaged such as a crack. In addition, since the two plate-like members sandwiching the flange portion are fixed to each other by a fixing member, the plate is subjected to vibration during molding, etc., as in a conventional electromagnetic tube forming coil bonded with an adhesive. The member does not separate. Thereby, it becomes possible to use repeatedly.

  You may fix the said plate-shaped member to an installation stand with the said fixing member. This electromagnetic tube-forming coil can easily and reliably fix the plate-like member to the installation table by the fixing member, so that the durability is improved and it is difficult to be damaged even after repeated use.

  In the present invention, since the shaft core and the flange portion are integrally formed, the base end portion is unlikely to be damaged such as a crack. Further, in order to fit the flange portion into the hole of the plate-like member and fix this plate-like member to the installation base, like a conventional electromagnetic tube expansion coil in which the plate-like member and the flange portion are bonded with an adhesive. The plate-like member and the flange portion are not separated due to vibration during molding. As a result, durability is improved and it can be used repeatedly.

  According to the present invention, since the shaft core and the flange portion are integrally formed, the durability of the base end portion is improved, and the base end portion is formed by at least two plate-like members fixed to each other by the fixing member. Since the flange portion formed between the two is sandwiched between them, it becomes difficult to separate them compared to the conventional coil for forming an electromagnetic tube, in which the plate-like member and the flange portion are bonded, and can be used repeatedly. .

  Hereinafter, an electromagnetic tube expansion forming coil according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view schematically showing an electromagnetic tube forming coil of the present embodiment. The coil 1 for electromagnetic tube expansion according to this embodiment is a coil for forming an electromagnetic tube for forming a tubular or tubular workpiece such as a metal tube. As shown in FIG. A flange portion 3 having a diameter larger than that of the shaft portion 2 is provided at a base end portion of the wound shaft portion 2, and a terminal portion 5 projects from the flange portion 3. A pair of sandwiching plates 6 and 7 are disposed so as to sandwich the flange portion 3 in the axial direction of the shaft portion 2, and the sandwiching plates 6 and 7 are fixed to each other by a fixing member such as a screw 10.

  The portion other than the conducting wire 4 of the shaft portion 2 and the flange portion 3 in the electromagnetic pipe expansion forming coil 1 are formed of an insulating material. As the structure of the shaft portion 2, for example, an insulating resin is used, and a conductive wire 4 is wound around a shaft core integrally formed with the flange portion 3. An insulating resin layer is formed on the wound conductive wire 4. Has been.

  Further, the sandwiching plates 6 and 7 are formed with holes 8 and 9 for fitting with the flange portion 3, respectively. For example, the hole 8 provided in the clamping plate 6 disposed on the tip end side of the shaft portion 2 includes a hole 8 a having a diameter substantially equal to the diameter of the flange portion 3 and a hole 8 b having a diameter substantially equal to the diameter of the shaft portion 2. Are continuously formed coaxially. Moreover, the hole 9 provided in the clamping plate 7 disposed on the terminal part 5 side has a hole 9 a having a diameter substantially equal to the diameter of the flange part 3, a diameter smaller than the diameter of the flange part 3, and the terminal part 5. A hole 9b of a size that can be inserted is continuously formed coaxially. The surface on the hole 8a side of the sandwiching plate 6 and the surface on the hole 9a side of the sandwiching plate 7 are overlapped, and the flange portion 3 is fitted into the holes 8a and 9a, and the shaft portion 2 is inserted into 8b. The terminal portion 5 is inserted through the hole 9b.

  Further, screw holes 11 and 12 are formed in the sandwiching plates 6 and 7, respectively. By inserting the screw 10 into the screw holes 11 and 12, the sandwiching plates 6 and 7 are fixed to each other. The flange portion 3 is held between the holding plates 6 and 7. The sandwiching plates 6 and 7 are preferably made of the same material as the flange portion 3 and the shaft core. Thereby, the clamping plates 6 and 7 and the flange part 3 can be mutually fixed with an adhesive agent etc., and an intensity | strength can be improved. In the electromagnetic tube-forming coil 1 of the present embodiment, since the bonding area between the sandwiching plates is wider than that of the conventional electromagnetic tube-forming coil 61 shown in FIG. 4, the strength increases and cracks are less likely to occur. Further, even when a crack occurs, the life until breakage is longer than that of the conventional electromagnetic pipe forming coil 61. Further, after the sandwiching plates 6 and 7 and the flange portion 3 are bonded, the sandwiching plate 7 and the flange portion may be further fixed to each other by the screws 17. Thereby, intensity | strength can be improved more.

  The coil 1 for electromagnetic tube expansion according to the present embodiment is fixed to the installation base 13 by screwing the screws 10 fixing the sandwiching plates 6 and 7 to the screw holes 14 formed in the installation base 13. Is done.

  Next, the manufacturing method of the coil 1 for electromagnetic tube expansion forming of this embodiment is demonstrated. The electromagnetic tube forming coil 1 can be manufactured by the following method. First, the shaft core around which the conducting wire 4 is wound and the flange portion 3 are integrally formed of the same material. As the method, for example, there is a method of using a cylindrical material made of an insulating resin, forming a small-diameter portion around which the conductive wire 4 is wound by cutting, and setting the unprocessed portion as the flange portion 3. Next, the conducting wire 4 is wound around the shaft core. And while forming the insulating resin layer in the outer periphery of the conducting wire 4 and an axial core, the terminal part 5 is formed.

  Thereafter, for example, the shaft portion 2 is inserted into the hole 8 of the holding plate 6 made of the same material as the flange portion 3 and the shaft core, and the flange portion 3 is fitted into the hole 8a. Further, for example, the terminal portion 5 is inserted into the hole 9 of the holding plate 7 made of the same material as the flange portion 3 and the shaft core, and the flange portion 3 is fitted into the hole 9a. Thereby, the clamping plate 6 and the clamping plate 7 are overlapped. Then, the screw holes 11 of the clamping plate 6 and the screw holes 12 of the clamping plate 7 are aligned, and the screws 10 are screwed into the screw holes 11 and 12, thereby fixing the clamping plates 6 and 7 to each other. The flange portion 3 is clamped by the clamping plates 6 and 7. At this time, it is preferable that the clamping plate 6, the clamping plate 7 and the flange portion 3 are bonded together with an adhesive or the like. In order to further increase the strength, the clamping plate 7 and the flange portion 3 may be fixed by the screw 17.

  Next, the operation of the electromagnetic tube forming coil 1 of the present embodiment, that is, an electromagnetic tube expanding method using the electromagnetic tube forming coil 1 of the present embodiment will be described. FIG. 2 is a conceptual diagram showing an electromagnetic tube expansion forming method. When performing electromagnetic tube forming using the electromagnetic tube forming coil 1 of the present embodiment, first, as shown in FIG. 1, the screw 10 that fixes the clamping plates 6 and 7 to each other is installed on the installation base 13. The electromagnetic pipe expansion forming coil 1 is fixed at a predetermined position on the installation base 13 by being screwed into the screw hole 14 formed in the above.

  Next, as shown in FIG. 2, the shaft portion 2 around which a conducting wire (not shown) is wound is inserted into a metal tube 15 that is a workpiece, and these are arranged at predetermined positions of the forming die 16. To do. Then, a large impact current is caused to flow from the terminals 5a and 5b to the conducting wire to generate a magnetic field around the shaft portion 2. At this time, the metal tube 15 receives a strong expansion force due to the repulsive force of the magnetic field, and is pressed against the forming die 16 to be expanded.

  The electromagnetic tube forming coil 1 of the present embodiment secures the electromagnetic tube forming coil 1 in order to fix the holding plates 6 and 7 to the installation base 13 with the flange portion 3 held between the holding plates 6 and 7. While being able to fix to the installation stand 13, even if it receives a vibration repeatedly at the time of shaping | molding, it can prevent that the clamping plates 6 and 7 and the flange part 3 isolate | separate. Further, since the bobbin and the flange portion are integrally formed of the same material, it is possible to prevent breakage such as cracks between the shaft portion 2 and the flange portion 3. As a result, durability is improved and it can be used repeatedly.

  In addition, in the electromagnetic tube-forming coil 1 of the present embodiment, the clamping plates 6 and 7 are fixed to the installation base 13 with screws 10, but the present invention is not limited to this, and the fixing member is For example, a vice can be used.

  In the coil 1 for electromagnetic tube expansion according to the present embodiment, a conducting wire having a circular cross section is used. However, the present invention is not limited to this, and a conducting wire having a rectangular cross section may be used. You may use the tubular hollow conducting wire in which the hollow part was formed in the inside. Since the lead wire 4 is a hollow lead wire and the coil portion is cooled by flowing a coolant through the hollow portion at the time of molding, temperature rise can be prevented, so that durability is improved. Furthermore, the outer surface of the conducting wire 4 may be covered with an insulating material. Thereby, the deformation | transformation and damage of a conducting wire by the electromagnetic repulsive force and vibration at the time of shaping | molding can be prevented.

It is sectional drawing which shows typically the coil for electromagnetic pipe expansion shaping | molding of embodiment of this invention. It is a conceptual diagram which shows the electromagnetic pipe expansion forming method. It is sectional drawing which shows the conventional coil for electromagnetic pipe expansion shaping | molding typically. It is sectional drawing which shows typically the other conventional coil for electromagnetic pipe expansion shaping | molding.

Explanation of symbols

1, 51, 61; Electromagnetic tube expansion forming coil 2, 52, 62; Shaft part 3, 53, 63; Flange part 4, 54, 64; Conductor 5, 55, 65; Terminal part 5a, 5b; Terminal 6, 7 ; Clamping plate 8, 8a, 8b, 9, 9a, 9b, 56a; hole 10, 17, 57, 59, 68, 70; screw 11, 12, 14; screw hole 13, 58, 69; installation base 15; metal Tube 16; Mold 57, 56, 66, 67; Fixing plate

Claims (2)

A shaft core, a conductive wire wound around the shaft core, a flange portion integrally formed with the shaft core at a base end portion of the shaft core, and the flange portion are sandwiched in the axial direction of the shaft core An electromagnetic tube-expanding coil comprising at least two plate-like members and a fixing member for fixing the plate-like members to each other. The coil for electromagnetic tube expansion molding according to claim 1, wherein the plate member is fixed to an installation base by the fixing member.

Images