JP4910824B2 - Antenna core - Google Patents

Description

  The present invention relates to a magnetic core for an antenna mounted on a vehicle, a house door, and a mobile phone, and a method for manufacturing the same.

  Patent Document 1 discloses an iron core for an antenna in which a laminate of a thin amorphous magnetic alloy mainly composed of iron or cobalt is fixed with a resin. Compared to a magnetic core made of a laminate of silicon steel plates, it has excellent high frequency characteristics and can reduce signal attenuation. Furthermore, since it is being fixed with resin, rigidity can be maintained.

  Patent Document 2 discloses an antenna magnetic core prepared by laminating an amorphous metal thin body containing iron and cobalt as main components and then performing pressure heat treatment. It is characterized in that magnetic properties such as magnetic permeability and iron loss are improved by performing pressure heat treatment. Furthermore, a heat resistant resin is provided between the thin bodies, and the tensile strength is excellent.

  In Patent Document 3, a cobalt-based amorphous magnetic thin body is wound around a resin bobbin to form an antenna magnetic core. By winding the amorphous magnetic thin body a plurality of times so as not to shift to the bobbin, high transmission and reception performance can be stably obtained.

  In Patent Document 4, a magnetic thin body is laminated through a rubber-like member or an air layer, and a peripheral part is fixed with an epoxy resin or a urethane potting material to create a core (antenna magnetic core). It is characterized by excellent bendability.

  Further, Patent Document 5 and Patent Document 6 can be cited as methods for manufacturing the antenna magnetic core. Patent Document 5 is characterized in that a magnetic metal thin body having a resin layer applied on one side or both sides is laminated and laminated and welded by hot pressing, hot roll, high frequency welding or the like.

Patent Document 6 forms a magnetic core for an antenna by inserting a laminate (core) of a thin film-like magnetic body into a heat-shrinkable tube and then contracting the heat-shrinkable tube by heat treatment.
JP-A-5-267922 Japanese Patent Publication No. 2003-060175 JP 2004-166071 A JP 2003-283231 A JP 2005-116959 A JP 2005-033278 A

  However, according to the description of Patent Document 1 and Patent Document 2, the side surface of the iron core is not coated with resin, and the metal is exposed. For this reason, when used outdoors such as automobile exterior parts, it oxidizes with humidity or water, resulting in rust. As a result, there is a problem that the magnetic characteristics are deteriorated and the antenna characteristics are deteriorated.

  Further, since the antenna core is fixed with a highly rigid resin, the antenna magnetic core is rigid. For this reason, when mounted on a curved shape component such as an automobile handle, the handle cannot follow the shape of the handle, resulting in useless space. Therefore, it is difficult to use in the case of a thin and curved handle.

  On the other hand, according to the description of Patent Document 3, since a cobalt-based amorphous magnetic thin body is used, rust hardly occurs. However, since cobalt is a rare metal, it has a drawback of high cost.

  According to the description of Patent Document 4, since the magnetic thin bodies are interposed between the air layers or rubber-like members, the antenna core portion that is a laminate can be deformed. In order to obtain moisture resistance and water resistance, it is necessary to cover the entire surface of the laminate with the surrounding member. However, when an epoxy resin or urethane potting material as used in the examples is applied to the entire surface of the laminate, there is a problem that rigidity and thickness increase, deformation is difficult, and thinning is difficult. Further, it takes time to cure the epoxy resin or the urethane potting material, and the productivity is not excellent.

  According to the description of Patent Document 5, since the resin adhesive layer is fixed between the magnetic metal thin bodies, the rigidity and thickness are increased, and there is a problem that it is difficult to deform and thin. Further, the side surface of the magnetic metal thin laminate is not coated with resin, and the metal is exposed. Therefore, the water resistance is not considered.

  According to the description in Patent Document 6, there arises a problem that it is difficult to insert an unfixed thin film magnetic body laminate into a tube without shifting. Moreover, although the side surface of the laminate is covered with a heat-shrinkable tube, the end portion is closed only by the heat-shrinkage of the tube and is not completely sealed, so that moisture resistance or water resistance is not considered. Moreover, since a gap is formed between the tube and the laminate, there arises a problem that sufficient magnetic properties cannot be obtained.

  The present invention has been made in view of the above-described conventional circumstances, and provides a thin antenna core that is excellent in moisture resistance and water resistance, has flexibility, and can be manufactured at low cost, and a method for manufacturing the same. This is a problem to be solved.

  According to a first aspect of the present invention, there is provided an antenna magnetic core including a laminate formed by laminating iron-based amorphous metal thin bodies, the laminate being covered with an extrusion molding resin, and the extrusion In the cross section of the laminate covered with the molding resin, the extrusion molding resin is contained between the iron-based amorphous metal thin bodies.

In a second aspect of the present invention, there is provided a magnetic core for antenna having a laminated body formed by laminating the iron-based amorphous metallic thin body, the said laminate in the process of extrusion molding the extrusion molding resin by covering by extrusion molding resin, in a cross section of the covered with extruded resin said laminate, wherein the extrusion resin intrudes between the iron-based amorphous metallic thin body .

In a third aspect of the present invention, the iron-based amorphous metal thin bodies have portions in direct contact with each other.

In a fourth aspect of the present invention, the laminate covered with the extrusion molding resin has an R-shaped corner.

In a fifth aspect of the present invention, the film formed of the extrusion molding resin is 2 μm or more and 500 μm or less.

  In a sixth aspect of the present invention, the magnetic flux density of the iron-based amorphous metal thin body is 1.2 T or more.

In a seventh aspect of the present invention, an end portion of the laminated body covered with the extrusion molding resin is covered with a resin cap.

  In an eighth aspect of the present invention, an end portion of the laminate covered with the extrusion molding resin is coated with a resin.

  In a ninth aspect of the present invention, the antenna magnetic core is housed in a vehicle door handle.

  In a tenth aspect of the present invention, the antenna magnetic core is a transmission antenna magnetic core.

In an eleventh aspect of the present invention, in a method for manufacturing an antenna magnetic core formed by stacking iron-based amorphous metal thin bodies, a first step of stacking a plurality of strip-shaped iron-based amorphous metal thin bodies; A second step of introducing the laminate of the iron-based amorphous metal thin body into a crosshead of an extruder, and the periphery of the laminate of the iron-based amorphous metal thin body and the iron-based amorphous A third step of filling the space between the metal thin bodies with the melt-pressed extrusion molding resin, and a laminate of the iron-based amorphous metal thin bodies coated with the extrusion molding resin, It is characterized by comprising a fourth step of passing through a die and molding, and a fifth step of cooling the molded product.

  In a twelfth aspect of the present invention, the molded product is cut into a predetermined length, and an end portion of the molded product is covered with a resin cap, and bonded or welded.

  In a thirteenth aspect of the present invention, the molded product is cut into a predetermined length, and an end of the molded product is coated with a molten resin.

  According to the first aspect of the present invention, excellent moisture resistance and water resistance can be exhibited by covering the laminate of the iron-based amorphous metal thin body with the resin for extrusion molding. In addition, since the iron-based amorphous metal thin body is securely fixed with the resin for extrusion molding, excellent magnetic properties can be obtained.

  According to invention of Claim 2, the outstanding moisture resistance and water resistance can be exhibited by covering the said laminated body with the said resin in the process of extruding resin. Further, since the iron-based amorphous metal thin body is securely fixed with resin, excellent magnetic properties can be obtained.

  According to the third aspect of the invention, since the iron-based metal thin bodies have portions in contact with each other, a thin and flexible antenna magnetic core can be obtained.

  According to the invention described in claim 4, since the corner of the molded product is not a pin angle, a coil (copper wire) used when used as an antenna can be wound without useless gaps, and excellent magnetic characteristics Can be obtained.

  According to invention of Claim 5, size reduction is attained by using a thin film. If it is less than 2 μm, the resin layer may be broken by the end of the iron-based amorphous metal thin body. If it is 500 μm or more, the thickness increases and becomes rigid.

  According to the sixth aspect of the invention, sufficient antenna performance can be obtained when the magnetic flux density of the iron-based amorphous metal thin body is 1.2 T or more. When an amorphous metal thin body of less than 1.2T is used, it is necessary to increase the number of laminated amorphous metal thin bodies in order to obtain the same performance, and the overall thickness of the antenna magnetic core increases.

  According to invention of Claim 7, the edge part of a molded object is completely sealed with the resin cap, and generation | occurrence | production of the rust by the influence of water or humidity can be prevented.

  According to the eighth aspect of the present invention, the end of the molded product is completely sealed by being coated with the resin, and the occurrence of rust due to the influence of water or humidity can be prevented.

  According to the ninth aspect of the present invention, since it is covered with a thin resin layer without useless gaps, it is thin and can be deformed. It becomes possible.

  According to the invention of claim 10, a magnetic core for a transmitting antenna having a volumetric efficiency in magnetic characteristics can be obtained. The transmission antenna magnetic core is required to further improve the volumetric efficiency in magnetic properties than the reception antenna magnetic core.

  According to the eleventh aspect of the present invention, continuous production is possible at a low cost by performing a series of steps from laminating amorphous metal thin bodies to extrusion molding. Further, by winding the molded product in a roll shape, the length can be freely set according to the application, and waste of material can be reduced.

  According to invention of Claim 12, the edge part of a molded object is completely sealed with the resin cap, and generation | occurrence | production of the rust by the influence of water or humidity can be prevented.

  According to the thirteenth aspect of the present invention, the end of the molded product is completely sealed by being coated with the resin, and the occurrence of rust due to the influence of water or humidity can be prevented.

  Hereinafter, the antenna magnetic core 10 of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an antenna configuration using an antenna magnetic core 10 of the present invention. The antenna core 10 fixed by covering the laminate 20 (see FIG. 2) of the iron-based amorphous metal thin body with the synthetic resin 30 is wound around the coated copper wire 40 30 times.

(First embodiment)
A first embodiment of the present invention will be described with reference to the drawings. FIG. 2 is an overview of the antenna core of the present invention. FIG. 3 is a schematic diagram of a cross section of the antenna magnetic core according to Embodiment 1 of the present invention, and FIG. 4 is an electron micrograph of an actual molded product. Thirty iron-based amorphous metal thin bodies 21 are laminated, and the whole is covered with a layer of extrusion molding resin. The number of laminations of the iron-based amorphous metal thin bodies 21 may be adjusted by adjusting the magnetic flux density and the number of sheets so that the magnetic characteristics can be obtained with a size acceptable as an antenna, and is not limited to 30 sheets. When the antenna core for transmission is housed in the vehicle door handle, 25 to 35 are exemplified.

  The iron-based amorphous metal thin body 21 is exemplified by a thin body having a width of 4 mm, a thickness of 21 μm, and a magnetic flux density of 1.2 T or more. The iron-based amorphous metal thin body 21 contains 90 mass% or more of iron, and examples of other components include Si, B, Mn, and Cr, but are not limited thereto.

  The extruded resin penetrates between the iron-based amorphous metal thin bodies. Therefore, as shown in FIG. 4, it is observed that the cross section of the laminate has a resin entering the end between the metal thin bodies. The amount of the resin entering is not limited, but the resin does not enter and the iron-based amorphous metal thin body has a portion in direct contact with each other. The corners of the laminate are R-shaped.

In the first embodiment, polyethylene terephthalate is used as the extrusion molding resin 30, but it is not limited to this. Polyolefin, polyamide, acrylonitrile butadiene styrene copolymer, acrylonitrile ethylene propylene rubber styrene copolymer, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyphenylene ether, polyether sulfone, polymethyl methacrylate, polybutylene terephthalate, polyethylene terephthalate, polycarbonate , Polyurethane, fluorinated ethylene propylene, ethylene tetrafluoroethylene copolymer, polyfluoromethyl vinyl ether, polyvinyl fluoride, silicone, polyamideimide, polyimide, biodegradable resin, liquid crystal polymer, styrene elastomer, olefin elastomer, urethane Examples are elastomers, ester elastomers, and amide elastomers. Resins excellent in heat resistance and chemical resistance are preferred.
The thickness of the resin layer 30 is preferably 2 μm or more and 500 μm or less. In particular, 100 μm or less, 50 μm or less, and 25 μm or less are exemplified. The thinness enables miniaturization, thinning, and bending, and magnetic characteristics are easily obtained. If it is 2 μm or less, the resin layer may be broken by the corners of the amorphous metal thin body.

  Next, a manufacturing method will be described. As shown in FIG. 6, the strip-shaped iron-based amorphous metal thin body 21 is wound around a bobbin 50. Thirty bobbins 51 each wound with a strip-shaped iron-based amorphous metal thin body 21 are prepared and set in a holder. In FIG. 6, although it has arranged vertically with respect to the molding machine 53, it is not restricted to this. It may be horizontal or diagonal.

  The strip-shaped iron-based amorphous metal thin body 21 is pulled out from each bobbin 51 and laminated by the laminated portion 52 (first step). Thereafter, the laminate 20 is inserted into the cross head 55 of the extruder 53 (second step), and the periphery is filled with the melt-pressed extrusion molding resin 54 (third step). The cross head 55 is a coating die that turns the laminate 20 in the extrusion direction. Molding is performed by passing the die 56 (die) (fourth step), and the molded product is cooled (fifth step) and continuously wound into a roll. Thereafter, it is cut into a length of 73 mm, and a cap 31 made of PET resin coated with an epoxy adhesive is attached and heated for 30 minutes to be cured (sixth step).

(Second embodiment)
A second embodiment of the present invention will be described with reference to FIG. The difference from the first embodiment is that after cutting, a resin cap 31 made of polyethylene terephthalate to which no epoxy resin is applied is attached and welded (sixth step). Examples of the welding method include thermal welding, high-frequency welding, vibration welding, and the like.

(Third embodiment)
Embodiment 3 of the present invention will be described with reference to FIG. The difference from the first embodiment is that after cutting, the cut portion is dipped in a solution of epoxy resin 32 and coated (seventh step).

(Evaluation)
For the embodiment of the present invention, the amplitude magnetic permeability before and after being left at high temperature and high humidity was evaluated. In the comparative example, an epoxy resin was applied to both surfaces of the same iron-based amorphous magnetic thin body as in the example, 30 sheets were laminated, and then the heat treatment was performed to cure the epoxy resin, thereby creating an antenna core. As shown in FIG. 1 for both the example and the comparative example, the coated copper wire 40 was wound 30 times to create an antenna. The copper wire diameter of the coated copper wire 40 was 0.55 mm, the coating thickness was 0.2 mm, and Φ0.2 mm × 7 bundles. The measurement was performed using an AC BH analyzer SY-8232 (manufactured by Iwasaki Tsushin Co., Ltd.).

  As shown in FIG. 7, each sample put in the case 73 was inserted into the center of the evaluation bobbin 70 around which the coated copper wire 40 was wound, and the amplitude relative permeability μa was measured under the condition of a frequency of 130 kHz. The measurement was performed by connecting to the primary side and the secondary side of AC BH analyzer SY-8232 (Iwasaki Tsushin Co., Ltd.). The width of the case is 5 mm.

First, the μ measurement mode is selected, the winding width Le of the coil 71 of the evaluation bobbin 70, the cross-sectional area Ae of the coil 71 on the plane orthogonal to the winding axis of the coil 71, and the volume Ve (Le X Ae) was set. In this evaluation, Le = 32.2 mm, Ae = 10.008 mm ² and Ve = 132.46 mm ³ were set as set values. A setting frequency f = 130 KHz was set, and an amplitude relative permeability μa and an inductance L at a magnetic field H = 1000 A / m were measured. Thereafter, each sample was allowed to stand for 1000 hours in a high-temperature and high-humidity phase at 85 ° C. and RH 85%, and then the amplitude relative permeability μa and the inductance L were measured in the same manner as the initial product. The results are shown in Table 1.

  In the first embodiment, the second embodiment, and the third embodiment, the occurrence of rust was not visually observed even after 1000 hours, and it was confirmed that there was no decrease in amplitude permeability and inductance. On the other hand, in the comparative example, rust was generated after 1000 hours, and it was confirmed that both the amplitude magnetic permeability and the inductance were lowered.

Configuration of antenna using magnetic core for antenna External view of antenna magnetic core (first embodiment and second embodiment) Schematic diagram of cross section of magnetic core for antenna Electron micrograph of a cross section of an antenna magnetic core (first embodiment) External view of antenna core (third embodiment) Schematic diagram of lamination and extrusion process of antenna magnetic core Schematic diagram of evaluation core

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Magnetic core 20 for antennas Laminate of iron-based amorphous metal thin body 21 Iron-based amorphous metal thin body 30 Extrusion resin 31 Resin cap 32 Resin coating 40 Coated copper wire 50 Bobbin 51 Iron-based amorphous Bobbins 52 laminated with thin metal thin bodies 53 laminating sections 53 extrusion molding machines 54 extrusion molding resins 70 evaluation bobbins

Claims (13)

An antenna magnetic core including a laminate formed by laminating iron-based amorphous metal thin bodies,
The laminated body is covered with an extrusion molding resin, and the extrusion molding resin enters between the iron-based amorphous metal thin bodies in a cross section of the laminated body covered with the extrusion molding resin. Magnetic core for antenna. An antenna magnetic core including a laminate formed by laminating iron-based amorphous metal thin bodies,
By covering the laminate with the extruded resin in the process of extruding the extrusion molding resin, in a cross section of the covered with extruded resin said laminate, the extrusion molding resin wherein the iron-based non An antenna magnetic core characterized in that it penetrates between thin crystalline metal bodies. In the antenna core according to claim 1 or 2,
The magnetic core for an antenna, wherein the iron-based amorphous metal thin bodies have portions in direct contact with each other. In the antenna core according to any one of claims 1 to 3,
The antenna core according to claim 1, wherein the laminate covered with the extrusion molding resin has a rounded corner. In the antenna core according to any one of claims 1 to 4,
The antenna core according to claim 1, wherein the coating film formed of the extrusion molding resin has a thickness of 2 µm to 500 µm. In the antenna magnetic core according to any one of claims 1 to 5,
A magnetic core for an antenna, wherein the iron-based amorphous metal thin body has a magnetic flux density of 1.2 T or more. The antenna magnetic core according to any one of claims 1 to 6,
An antenna core according to claim 1, wherein an end of the laminate covered with the extrusion resin is covered with a resin cap. In the antenna core according to any one of claims 1 to 7,
The antenna core according to claim 1, wherein an end of the laminate covered with the extrusion molding resin is coated with a resin. The antenna magnetic core according to any one of claims 1 to 8,
The antenna magnetic core, magnetic core for antenna, characterized in that it is housed in the door handle for a vehicle. The antenna magnetic core according to any one of claims 1 to 9,
The antenna core is a transmitting antenna core . In the manufacturing method of the antenna core formed by laminating iron-based amorphous metal thin bodies,
A first step of laminating a plurality of strip-shaped iron-based amorphous metal thin bodies;
A second step of introducing the laminate of the iron-based amorphous metal thin body into a crosshead of an extruder;
Filling the space between the iron-based amorphous metal thin bodies and the cross-section of the laminate with the melt-pressed extrusion molding resin between the iron-based amorphous metal thin bodies . Process,
A fourth step of forming a laminate of the iron-based amorphous metal thin body coated with the extrusion molding resin through a die of an extrusion molding machine;
A method of manufacturing a magnetic core for an antenna, comprising: a fifth step of cooling the molded product. In the manufacturing method of the antenna core according to claim 11,
A method of manufacturing a magnetic core for an antenna, comprising: a sixth step of cutting the molded product into a predetermined length, covering an end of the molded product with a resin cap, and bonding or welding. In the manufacturing method of the antenna core according to claim 11,
A method for manufacturing a magnetic core for an antenna , comprising: a seventh step of cutting the molded product into a predetermined length and coating an end of the molded product with a molten resin.