JP2004040044A - Coil for electromagnetic expanded tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coil for, an electromagnetic expanded tube in which an insulating resin for covering a conductor strand is not damaged or deteriorated and the resin is not damaged or its insulation is not deteriorated even when the resin is repeatedly used even when is used for expanding the tube of a high-strength material and a high-deformation material. <P>SOLUTION: The conductor strands 1 are wound on a bobbin 9 made of a conductor. The surfaces of the opposed strands 1 are in parallel with each other, and a periphery of the strands is covered with an insulating substance 2 having a thickness T. An interval H between the adjacent strands 1 in a coil axial direction is 2T. An outer peripheral insulator 3 is held on a peripheral surface of an intermediate diameter part 11 and an outer peripheral surface of the strands 1 wound on a minimum diameter part 10. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electromagnetic expansion coil used for electromagnetic forming of metal.
[Prior art]
In electromagnetic expansion molding, the electric charge stored at a high voltage is instantaneously discharged to a current-carrying coil to form an extremely short-time strong magnetic field. This is a technology that receives a strong expansion force and is pressed against the outer mold to form.
[0003]
Electromagnetic forming is suitable for forming an aluminum alloy which is a good conductor of electricity, and is used for forming a groove in an aluminum alloy pipe or joining aluminum alloy pipes to each other. Also, the application of electromagnetic expansion forming to the processing of bending the end of an aluminum alloy pipe, the processing of a large deformation such as caulking of a large-diameter pipe, and the processing of a high-strength material is being studied. For example, application to processing or caulking of frame materials of vehicles, automobiles, two-wheeled vehicles, and the like has been studied.
[0004]
Conventionally, a coil used for these electromagnetic expansion moldings has a copper wire having a circular cross section on an axial center made of an insulating resin as disclosed in JP-A-7-153617 and JP-A-6-238356. In addition to winding, the space between the copper wires is filled with an insulating resin.
[0005]
[Problems to be solved by the invention]
When such high-strength material processing and processing with a large amount of deformation are performed using such a coil, a force in a direction in which the conductor element itself expands is applied to the conductor element itself, so that the conductor element is filled around the conductor element. There is a possibility that the insulating resin may be damaged. In particular, when a wire having a circular cross section is used, the thickness of the resin becomes thinnest between the apexes of the cross section circles of the opposing conductors, and the strength is weakened. In addition, since the insulating resin in this area has a small coefficient of thermal expansion, if the conductor element expands thermally due to the Joule heat generated in the conductor element when the coil is used repeatedly, the insulating resin will be distorted due to thermal expansion. As a result, there is a possibility that a gap is generated between the conductor strands, and the insulation property is deteriorated. In addition, when a circular cross section is used, when forming an insulating layer by impregnating the resin, the resin does not sufficiently spread around the conductor, and there is a concern that pores may enter the surface portion of the shaft core in particular, thereby impairing the insulating property. there were.
[0006]
The present invention has been made in view of such a problem, and even when used for electromagnetic expansion processing of a high-strength material and electromagnetic expansion processing of a material having a high deformation amount, the insulating resin covering the conductor strand may be damaged. It is an object of the present invention to provide a coil for electromagnetic expansion which does not cause insulation resin to be damaged or insulation properties to be degraded even when used repeatedly.
[0007]
[Means for Solving the Problems]
The coil for electromagnetic expansion according to the present invention is the coil for electromagnetic expansion in which a conductor wire is wound around an insulated bobbin portion. The conductor wire is wound around the bobbin so that the wire interval H between conductor wires adjacent in the coil axis direction is 2T. And
[0008]
In the coil for electromagnetic expansion according to the present invention, for example, the bobbin portion is an intermediate diameter portion, a minimum diameter portion, a middle diameter portion, and a maximum diameter portion in a coil axis direction from the base end side toward the tip end side, The conductor wire is wound around the minimum diameter portion on the peripheral surface of the bobbin portion, and a step is formed by the intermediate diameter portion and the maximum diameter portion on the tip end side, and the step of the intermediate diameter portion is formed. An insulator is held on a peripheral surface and an outer peripheral surface of the conductor strand wound around the minimum diameter portion. In this case, it is preferable that the width of the step is 10 mm or more, and one or more other steps are formed in the step.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a sectional view showing a conductor element wire according to an embodiment of the present invention, FIG. 2 is a sectional view showing a state where the conductor element element is wound around a bobbin part, and FIG. 3 is a view showing a shape of the bobbin part. .
[0010]
The bobbin portion 9 made of an insulating resin is a portion corresponding to the core of the coil, and a flange portion 9a is provided at a base end thereof, and a portion on the tip end side is inserted into the work. The bobbin portion 9 inserted into the work has, on its peripheral surface, an intermediate diameter portion 11 having an intermediate outer diameter and an outer diameter of the intermediate diameter portion 11 from the base end side to the distal end side in the coil axis direction. A small minimum diameter portion 10, an intermediate diameter portion 11 having an intermediate outer diameter, and a maximum diameter portion 12 having a maximum outer diameter are formed so as to be adjacent to each other in the coil axis direction. A step 4 is formed by the outer diameter difference between the intermediate diameter portion 11 and the maximum diameter portion 12 on the tip side adjacent to each other, and the step 4 is formed between the minimum diameter portion 10 and the intermediate diameter portion 11 on both sides thereof. Two steps 5 are formed by the diameter difference.
[0011]
On the other hand, the conductor strand 1 of the coil has a rectangular or square cross section. An insulating material 2 is wound around the conductor strand 1 to insulate the conductor. The conductor element wire 1 is densely wound around the minimum diameter portion 10 of the bobbin 9 by one layer. In other words, the conductor element wire 1 is wound around the peripheral surface of the minimum diameter portion 10 so as to fit into the recess formed between the two steps 5 between the minimum diameter portion 10 and the two intermediate diameter portions 11. As shown in FIG. 1, adjacent conductor strands 1 are closely contacted so that there is no gap. Therefore, assuming that the thickness of the insulating material 2 coated around the conductor element 1 is T, the element interval H between the conductor elements 1 adjacent in the coil axis direction is 2T. An insulator 3 is coated on the outer surface of the wound conductor element wire 1 and on the intermediate diameter portion 11. The insulator 3 is held and fixed on the outer surface of the conductor strand 1 and the peripheral surface of the intermediate diameter portion 11 so as to fit into a recess formed between the step 4 and the flange 9a. In this manner, the insulator 3 covers the conductor element wire 1 and the intermediate diameter portion 11, and has a thickness such that the outer surface of the insulator 3 and the peripheral surface of the maximum diameter portion 12 are substantially flush. Have.
[0012]
The conductor element wire 1 of the present embodiment is covered with an insulating material 2 by insulation. As the insulating material 2, a fiber reinforced resin in which glass fiber or the like is impregnated with an epoxy resin or the like is used. Deformation can be reduced. Further, the cross section of the conductor strand 1 is such that the opposing strand surfaces are parallel to each other, and when the thickness of the insulating material 2 is T, the arrangement pitch H of the conductor strand 1 is H = H It is wound around the bobbin 9 so as to be 2T. For this reason, the insulating thickness between the wires becomes uniform, and only the reinforced insulating substance 2 is present. Therefore, even if an expansion force is applied to the coil by energization, the force is dispersed, so that the insulation is achieved. Layer breakage is reduced. In addition, since the surfaces of the adjacent conductor strands 1 are parallel to each other, there is little room for unnecessary voids to enter during resin impregnation and impairing insulation. The shape of the conductor wire may be any shape, such as a rectangle or a square, as long as parallelism between the wires can be maintained when the wire is wound. Is particularly preferable because the amount of
[0013]
Further, since the outer peripheral insulator 3 is held and fixed in the concave portion between the step 4 and the flange portion 9a, the outer peripheral insulator 3 insulates the conductor strand 1 from the work, and at the same time, the conductor strand 1 And surround and hold it. As a result, the outer peripheral insulator 3 has a function of preventing the conductor element wire 1 from expanding and deforming outward due to the force received during energization. Since the coil of this embodiment has a structure in which there is substantially no gap between the conductor strands 1, thermal expansion of the conductor strands 1 is prevented, and the conductor strands 1 are held on the peripheral surface of the bobbin portion 9. This is mainly the fastening force of the outer peripheral insulator 3, and by providing the step 4 at the end of the bobbin portion 9, the outer peripheral insulator 3 is firmly fixed to the bobbin portion 9. The strand 1 is stabilized. The width of the step 4 (length in the coil axis direction) is preferably 10 mm or more in order to firmly fix the outer peripheral insulator 3.
[0014]
Next, another embodiment of the present invention will be described. FIG. 4 is a sectional view showing another embodiment of the present invention. In the bobbin portion 9, a step 6 having a smaller diameter than the intermediate diameter portion 11 is formed in the step 4. The step 6 extends in the circumferential direction in a groove shape in the intermediate diameter portion 11. As described above, by providing the step 6 extending in a groove shape on the peripheral surface of the intermediate diameter portion 11 where the outer peripheral insulator 3 is disposed, the fixing property of the insulator 3 can be improved.
[0015]
【The invention's effect】
As described above, according to the present invention, the conductor strands are spirally wound, the surfaces of adjacent conductor strands are parallel to each other, and an insulating material is provided between the conductor strands. Since only the wires exist, the deformation of the conductor wires during energization can be reduced, and there is no breakage of the insulating layer between the wires. Further, there is no possibility that unnecessary voids may enter during resin impregnation and impair insulation. According to the invention of claim 2 of the present application, since the outer peripheral insulator held by the step is arranged, the conductor strand and the work are insulated from each other, and the conductor strand is moved outward by the force received when energized. To prevent deformation.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a conductor strand of a coil for electromagnetic expansion according to an embodiment of the present invention.
FIG. 2 is a sectional view showing the electromagnetic expansion coil.
FIG. 3 is a sectional view showing the bobbin part.
FIG. 4 is a sectional view showing a coil for electromagnetic expansion according to a second embodiment of the present invention.
[Explanation of symbols]
1: Conductor wire 2: Insulating substance 3: Outer peripheral insulator 4, 5: Step 9: Bobbin section 10: Minimum diameter section 11: Intermediate diameter section 12: Maximum diameter section

Claims (4)

In an electromagnetic expansion coil in which a conductor wire is wound around an insulating bobbin, the conductor wire has its opposing surfaces parallel to each other, and the periphery thereof is coated with an insulating material having a thickness of T. And a conductor wire wound around the bobbin so that a wire interval H between conductor wires adjacent in the coil axis direction is 2T. The bobbin portion has a middle diameter portion, a minimum diameter portion, a middle diameter portion, and a maximum diameter portion connected in the coil axial direction from the base end portion side to the tip end portion side, and the conductor strand is formed of a peripheral surface of the bobbin portion. Wound around the minimum diameter portion, a step is formed by the intermediate diameter portion and the maximum diameter portion on the tip end side, and is wound around the peripheral surface of the intermediate diameter portion and the minimum diameter portion. The coil for electromagnetic expansion according to claim 1, wherein an insulator is held on an outer peripheral surface of the conductor strand. The electromagnetic expansion tube coil according to claim 2, wherein the width of the step is 10 mm or more. 4. The coil for electromagnetic expansion according to claim 2, wherein one or more other steps are formed in the step. 5.

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