JP2008210863A - Hollow magnetic shield sheet and manufacturing method thereof, and coil having hollow magnetic shield sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly stiff hollow magnetic shield sheet that has a hole for inserting a terminal projecting in the thickness direction of a coil and is free in shape and plate thickness. <P>SOLUTION: In the magnetic shield sheet where magnetic powder is press-formed together with a binder, the hole for inserting the terminal projecting in the thickness direction of the coil joined to the sheet is formed at the center of the sheet. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to, for example, a perforated magnetic shield sheet used for magnetic shielding of a power transmission coil in a contactless power transmission system using an electromagnetic induction method, a manufacturing method thereof, and a perforated magnetic shield including the perforated magnetic shield sheet. The present invention relates to a coil with a sheet.

  In recent years, as a charger for charging batteries built into cordless devices (cordless devices) such as mobile phones, electric razor machines, desk cleaners, remote controllers, etc., a primary coil built into the charger and a secondary built into the device. A contactless rechargeable device in which a coil is magnetically coupled is known. In recent years, devices such as wristwatches, calculators, etc. that used to replace the battery when the electromotive force of the battery has been reduced have recently been developed to charge the built-in battery using a contactless method. ing. In this type of contactless rechargeable device, electric power can be supplied from the charger to the device by electromagnetic induction from the primary coil to the secondary coil without providing a contact point for electrically connecting the charger and the device. . As a coil for an electronic device such as a power transmission coil, a power receiving coil, an electronic key system antenna coil, etc. used in this contactless rechargeable device, a coil having a resin insulating layer formed on the surface (coil with resin sheath) is adopted. (For example, refer to Patent Documents 1 to 4).

The power transmission coil of the contactless rechargeable device is required to use a magnetic shielding sheet to shield the influence of an external metal body and improve the power transmission efficiency to the power receiving coil. Adoption is being considered.
Conventionally, with respect to the magnetic shielding sheet, for example, techniques disclosed in Patent Documents 5 and 6 have been proposed.
In Patent Document 5, a magnetic shielding composition obtained by applying a liquid magnetic shielding composition comprising at least one kind of soft magnetic particles, a polymer material, and a volatile solvent to at least one surface of an insulating support. A functional sheet is disclosed.
In Patent Document 6, a special nickel alloy magnetic shield is covered with a vinyl chloride magnetic shield sheet, and three hooks are provided, and a mobile phone antenna is hooked to shield the electromagnetic wave from the antenna, and the brain and eyeball are protected. An electromagnetic shielding plate for a mobile phone to protect is disclosed.
JP-A-5-258941 JP-A-6-302221 JP 2005-136342 A JP 2005-137173 A JP 2003-243877 A JP-A-9-223888

  However, since various types of magnetic shielding sheets known at present are weak in rigidity, it is difficult to maintain stable characteristics when combined with a power transmission coil as described above, and there is a drawback that the price is high.

  In addition, when a magnetic shield sheet and a coil are used in combination for a contactless rechargeable device, since the coil generally has a winding start terminal protruding in the thickness direction, when the coil is joined on a flat sheet surface, There has been a problem that the thickness of the coil with the magnetic shielding sheet is increased by the amount corresponding to the winding start terminal. In order to achieve the “lightness, thinness, and smallness” of equipment that is a market need, provision of a thin coil with a magnetic shielding sheet is required.

  The present invention has been made in view of the above circumstances, and does not require special equipment, and has a simple structure, a general press, a thermostatic bath, and magnetic powder, and protrudes in the thickness direction of the coil. An object of the present invention is to provide a perforated magnetic shielding sheet having a hole through which a terminal is inserted and having a high rigidity and a flexible shape and thickness.

  In order to achieve the above object, the present invention provides a magnetic shielding sheet obtained by press-molding magnetic powder together with a binder, and a terminal protruding in the thickness direction of a coil joined to the sheet is inserted in the center of the sheet. Provided is a perforated magnetic-shielding sheet characterized in that a hole is provided.

  In the perforated magnetic shield sheet of the present invention, the magnetic material preferably has a composition of 30 to 70% by mass of Mn—Zn ferrite and the balance of iron-based magnetic powder and nickel-based magnetic powder.

  In the punched magnetic-shielding sheet of the present invention, the binder is preferably a thermosetting epoxy resin.

The present invention also provides a lower mold, a first intermediate mold and a second intermediate mold that are provided with cavities corresponding to the shape of the magnetic sheet to be molded, and are sequentially stacked on the upper surface of the lower mold, and cavities of these intermediate molds It has a pressing part inserted into it, and has an upper mold that can be moved up and down with respect to the lower mold, and a hole is formed in the central part of the magnetic shielding sheet in the central part of the molding area of the lower mold Using a molding device provided with a convex portion for performing the above and a concave portion into which the convex portion can be fitted in the central portion of the pressing surface of the pressing portion of the upper mold,
In the cavity, put a powder material containing at least magnetic powder and a binder,
Next, the upper die is lowered, the pre-pressurization is performed by pressing the powder material in the cavity to produce a pre-pressurized body,
Next, the upper mold is raised, the second intermediate mold is removed, the upper surface of the first intermediate mold is used as a scraping surface, the upper portion of the pre-pressurizing body is scraped, and the upper surface of the convex portion of the lower mold is exposed,
Next, the upper mold is lowered, and the pre-pressurized body is pressed at high pressure to produce a sheet molded body having a hole in the center,
Next, the sheet molded body is heated to cure the binder, and a perforated antimagnetic sheet having a hole at the center is obtained.

  In the method for producing a perforated magnetic shield sheet of the present invention, the magnetic material preferably has a composition of 30 to 70% by mass of Mn—Zn ferrite and the balance of iron-based magnetic powder and nickel-based magnetic powder.

  In the method for producing a punched magnetic-shielding sheet of the present invention, the binder is preferably a thermosetting epoxy resin.

  In the manufacturing method of a perforated magnetic-shielding sheet of this invention, it is preferable that the press pressure in the said pre-pressurization is the range of 50-200 kg.

  In the manufacturing method of a perforated magnetic-shielding sheet of this invention, it is preferable that the press pressure in the said press molding is the range of 20-100 t.

  Further, the present invention is characterized in that the above-described perforated magnetic shield sheet and a coil having a terminal protruding in the thickness direction are joined in a state where the terminal is inserted through the hole of the perforated magnetic shield sheet. A coil with a perforated magnetic shield is provided.

  Since the perforated magnetic shield sheet of the present invention is provided with a hole through which a terminal protruding in the thickness direction of the coil to be joined to the sheet is provided, when the perforated magnetic shield sheet and the coil are joined, the coil By joining the terminals protruding in the thickness direction to the back side of the magnetic shielding sheet from the holes, a thin coil with a perforated magnetic shielding sheet can be provided. The perforated magnetic-shielding sheet of the present invention is formed by press-molding magnetic powder together with a binder, so it has high rigidity, good magnetic shielding performance, and has various thicknesses and shapes according to needs. It can be.

  According to the method for manufacturing a perforated magnetic-shielding sheet of the present invention, the thickness of the coil can be obtained with a molding die having a simple structure, a general press machine, a thermostatic bath or magnetic powder without requiring any special equipment. It is possible to efficiently manufacture a perforated magnetic shielding sheet having a hole for inserting a terminal protruding in the direction and having a high rigidity and a flexible shape and thickness.

The coil with a perforated magnetic shielding sheet of the present invention is formed by joining the above-described perforated magnetic shielding sheet and a coil having a terminal protruding in the thickness direction in a state where the terminal is led out from the hole to the back side of the magnetic shielding sheet. Therefore, it is possible to provide a thin coil with a perforated magnetic shielding sheet.
Further, by passing the winding start terminal of the coil whose inductance has been adjusted through the hole in the central portion of the magnetic shielding sheet and joining the magnetic shielding sheet, the winding end terminal can be joined to the perforated magnetic shielding sheet in an arbitrary direction.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1-5 is sectional drawing which shows one Embodiment of the manufacturing method of the coil with a perforated magnetic-shielding sheet | seat of this invention in order of a process. In these drawings, reference numeral 1 is a lower mold, 1A is a convex part, 2 is an upper mold, 2A is a concave part, 3 is a first intermediate mold, 4 is a second intermediate mold, 5 is a powder material, and 5A is a pre-pressurization. The body, 6 is a scraping plate, 7 is a jig receiving plate, 8 is a sheet tray, 9 is a sheet molded body, and 9A is a hole.

(Mold used)
In the present embodiment, as shown in FIG. 1, a cavity corresponding to the shape of the lower mold 1 and the magnetic sheet to be molded is provided, and the first intermediate mold 3 and the first intermediate mold 3 are sequentially stacked on the upper surface of the lower mold 1. 2. A molding apparatus having an intermediate mold 4 and an upper mold 2 having a pressing part inserted into the cavities of these intermediate molds 3 and 4 and provided so as to be movable up and down with respect to the lower mold 1 is used. . In this molding apparatus, a convex portion 1A is provided at the central portion of the lower mold 1, and a concave portion 2A into which the convex portion 1A is fitted is provided on the pressing surface corresponding to the convex portion 1A of the upper mold 2. Yes. The protruding height of the convex portion 1 </ b> A of the lower mold 1 is equal to the thickness of the first intermediate mold 3. By changing the cavity shape of the intermediate molds 3 and 4, magnetic sheets having various shapes and thicknesses such as a circle, an ellipse, an oval, a triangle, a quadrangle such as a square or a rectangle, and a pentagon or more polygon can be obtained. Can be manufactured.

(Powder material)
In the manufacturing method of the present invention, a powder material containing at least a magnetic powder and a binder is used as a material for the perforated magnetic shielding sheet.

  Examples of the magnetic material include ferrite-based magnetic powder, iron-based magnetic powder, nickel-based magnetic powder, cobalt-based magnetic powder, and the like, and magnetic powder obtained by mixing one or more of them can be used. In the present invention, preferable magnetic powder includes magnetic powder having a composition of 30 to 70% by mass of Mn—Zn ferrite, the balance being iron-based magnetic powder and nickel-based magnetic powder. A composition having a composition of 40 to 60% by mass and iron-based magnetic powder of 60 to 40% by mass is preferable.

Examples of the binder include an epoxy resin, a polyvinyl alcohol resin, a polyamide resin, a polyester resin, a phenol resin, and the like, and a thermosetting epoxy resin is particularly preferable.
The blending amount of the binder is preferably in the range of 1/20 to 1/40 mass, particularly about 1/30 mass of the total amount of the powder material.

(Powder material filling process)
In the present embodiment, when manufacturing a perforated magnetic-shielding sheet, first, as shown in FIG. 1, the upper mold 2 of the molding apparatus is raised, and the cavities provided in the first intermediate mold 3 and the second intermediate mold 4 Inside, an appropriate amount of the above-mentioned powder material is filled. The powder material needs to be sufficiently mixed in advance.

(Pre-pressurization process)
Next, as shown in FIG. 2, the upper die 2 is lowered to a pre-pressurizing position whose tip surface is higher than the upper surface of the first intermediate die, and the upper die 2 is pushed by an air press so that it can be scraped off. A pre-pressurizing step for producing the pre-pressurized body 5A is performed. The press pressure in this pre-pressurization step is preferably in the range of 50 to 200 kg. When this press pressure is less than the above range, the pre-pressurized body 5A is not sufficiently solidified, and tends to collapse when the second intermediate mold 4 is removed in the next step. On the other hand, if the pressing pressure exceeds the above range, the pre-pressurized body 5A becomes hard and it becomes difficult to wear it.
In this pre-pressurization step, the portion of the convex portion 1A provided at the center of the lower mold 1 is hardly pressurized because the powder material escapes into the concave portion 2A.

(Abrasion process)
Next, as shown in FIG. 3, the upper die 2 is raised, the second intermediate die 4 is further removed, and the upper portion of the pre-pressurizing body 5A is the edge of the scraping plate 6 with the upper surface of the first intermediate die 3 being a scraping surface. Then, a scraping process for aligning to a predetermined thickness is performed.
In this scraping step, it is preferable that all the powder material placed on the convex portion 1A of the lower mold 1 is scraped off and the tip surface of the convex portion 1A is exposed after scraping.

(Press molding process)
Next, as shown in FIG. 4, the second intermediate mold 4 is set on the first intermediate mold 3, the upper mold 2 is lowered, the pre-pressurizing body 5 </ b> A is high-pressure pressed, and a molding having a hole 9 </ b> A in the center is performed. A press molding process for producing the sheet 9 is performed. The press pressure in this press molding step is preferably in the range of 20 to 100 t in the case of a magnetic-shielding sheet having a diameter of 50 mm. When the pressing pressure is less than 20 t, the magnetic permeability of the obtained magnetic shielding sheet is lowered and the magnetic shielding performance is lowered. On the other hand, when the pressing pressure exceeds 100 t, the molded body easily protrudes from the mold.

(Release of molded sheet)
Next, as shown in FIG. 5, the lower mold 1 is removed, the end of the first intermediate mold 3 is supported by the jig receiving plate 7, set in an air press, and a molded sheet having a hole 9A in the center. 9 is dropped on a sheet tray 8 disposed below and released.

(Annealing process)
Next, the molded sheet 9 obtained as described above is placed in a thermostatic bath (not shown) and heated to perform an annealing step for curing the resin added as a binder. The temperature and treatment time of this annealing step are appropriately set according to the type of resin used as the binder. In the case of the above-described thermosetting epoxy resin, the heating temperature ranges from 100 to 180 ° C., and the heating time is 0. About 5 to 2 hours are preferable. After the annealing treatment, a perforated magnetic shield sheet 10 having a hole in the center is manufactured.

FIG. 6 is a perspective view showing an example of a perforated magnetic shield sheet obtained by the manufacturing method described above. The perforated magnetic-shielding sheet 10 of this example has a donut shape with a hole 10A in the center.
Since this perforated magnetic shield sheet 10 is provided with a hole 10A through which the winding start terminal 12 protruding in the thickness direction of the coil 11 joined to the sheet is provided, the perforated magnetic shield sheet 10 and the coil 11 are connected to each other. When joining, in the state which led out the winding start terminal 12 of the coil 11 to the back side of the magnetic-shielding sheet from the hole 10A, the thin coil 13 with a perforated magnetic-proof sheet can be provided.

  The perforated magnetic shielding sheet 10 is formed by press-molding magnetic powder together with a binder, so has high rigidity and good magnetic shielding performance, and has various thicknesses and shapes according to needs. can do.

  Furthermore, according to the manufacturing method of the above-mentioned perforated magnetic-shielding sheet, the coil 11 can be made of a simple mold, a general press, a thermostat, or magnetic powder without requiring special equipment. It is possible to efficiently manufacture a perforated magnetic shield sheet 10 having a hole 10A through which the winding start terminal 12 can be inserted and having a high rigidity and a flexible shape and thickness.

  FIG. 7 is a perspective view showing an example of a coil 11 used for manufacturing a thin coil 13 with a perforated magnetic shield sheet in combination with the perforated magnetic shield sheet 10. Although this coil 11 has illustrated the multilayer winding coil of 1 row, the kind of coil 11 is not limited to this illustration, Various conventionally well-known coils can be used. Further, the number of terminals of the coil 11 is not limited to two (winding start terminal and winding end terminal).

  FIG. 8 is a perspective view showing an example of a coil with a perforated magnetic shield sheet according to the present invention. This coil 13 with a perforated magnetic shield sheet is joined to the perforated magnetic shield sheet shown in FIG. 6 and the coil 11 shown in FIG. 7 with the winding start terminal 12 being led out from the hole 10A to the back side of the magnetic shield sheet. As a result, a thin coil with a perforated magnetic shielding sheet can be provided.

  That is, since the winding start terminal 12 protrudes in the coil thickness direction, the coil 11 is bent along the lower side of the coil when the coil 11 is joined to a magnetic-shielding sheet having no hole. In this state, the coil must be bonded to the magnetic shielding sheet, and as a result, the thickness of the coil with the magnetic shielding sheet is increased by the winding start terminal 12. In this example, by using a perforated magnetic shield sheet 10 having a hole 10A in the center, the winding start terminal 12 of the coil 11 is passed through the hole 10A and led to the back side of the magnetic shield sheet. Therefore, it is possible to eliminate the problem that the thickness increases excessively, and it is possible to reduce the thickness of the perforated coil 13 with the magnetically shielded sheet.

  Further, by passing the winding start terminal 12 of the coil 11 whose inductance has been adjusted through the hole 10A in the center of the perforated magnetic shield sheet 10 and joining it to the perforated magnetic shield sheet 10, the winding end terminal of the coil 11 can be connected in any direction. Can be bonded to the perforated magnetic shield sheet 10.

It is sectional drawing which shows the powder material filling process in one Embodiment of the manufacturing method by this invention. It is sectional drawing which similarly shows a pre-pressurization process. It is sectional drawing which similarly shows the abrasion process of a pre-pressurization body. It is sectional drawing which similarly shows a press molding process. It is sectional drawing which similarly shows the mold release process of a forming sheet. It is a perspective view which shows an example of the perforated magnetic-shielding sheet | seat of this invention. It is a perspective view which shows an example of a coil. It is a perspective view which shows an example of the coil with a perforated magnetic-shielding sheet of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Lower type | mold, 1A ... Convex part, 2 ... Upper type | mold, 2A ... Concave part, 3 ... 1st intermediate | middle type | mold, 4 ... 2nd intermediate | middle type | mold, 5 ... Powder material, 5A ... Pre-pressurization body, 6 ... Abrasion board , 7 ... Jig receiving plate, 8 ... Sheet tray, 9 ... Sheet molded body, 9A ... Hole, 10 ... Perforated magnetic shield sheet, 10A ... Hole, 11 ... Coil, 12 ... Winding start terminal, 13 ... Perforated Coil with magnetic shielding sheet.

Claims (9)

It is a magnetic shielding sheet formed by pressing magnetic powder together with a binder,
A perforated magnetic shield sheet, characterized in that a hole for inserting a terminal protruding in the thickness direction of a coil to be joined to the sheet is provided in the center of the sheet.   2. The perforated magnetic-shielding sheet according to claim 1, wherein the magnetic material has a composition of 30 to 70% by mass of Mn—Zn ferrite and the balance is iron-based magnetic powder and nickel-based magnetic powder.   The perforated magnetic shielding sheet according to claim 1 or 2, wherein the binder is a thermosetting epoxy resin. A lower die, a first intermediate die and a second intermediate die that are provided with a cavity corresponding to the shape of the magnetic sheet to be molded and are sequentially stacked on the upper surface of the lower die, and inserted into the cavities of these intermediate die A convex part for forming a hole in the central part of the magnetic-shielding sheet in the central part of the molding area of the lower mold. And using a molding device provided with a concave portion into which the convex portion can be fitted in the central portion of the pressing surface of the pressing portion of the upper mold,
In the cavity, put a powder material containing at least magnetic powder and a binder,
Next, the upper die is lowered, the pre-pressurization is performed by pressing the powder material in the cavity to produce a pre-pressurized body,
Next, the upper mold is raised, the second intermediate mold is removed, the upper surface of the first intermediate mold is used as a scraping surface, the upper portion of the pre-pressurizer is scraped, and the upper surface of the convex portion of the lower mold is exposed,
Next, the upper mold is lowered, and the pre-pressurized body is pressed at high pressure to produce a sheet molded body having a hole in the center,
Next, a method for producing a perforated magnetic-shielding sheet, wherein the sheet molded body is heated to cure the binder to obtain a perforated magnetic-shielding sheet having a hole at the center.   5. The method for producing a punched magnetic-shielding sheet according to claim 4, wherein the magnetic material has a composition of 30 to 70% by mass of Mn—Zn ferrite and the balance of iron-based magnetic powder and nickel-based magnetic powder. .   The method for producing a punched magnetic-shielding sheet according to claim 4 or 5, wherein the binder is a thermosetting epoxy resin.   The method for producing a punched magnetic-shielding sheet according to any one of claims 4 to 6, wherein a press pressure in the preliminary pressurization is in a range of 50 to 200 kg.   The method for producing a punched magnetic-shielding sheet according to any one of claims 4 to 7, wherein a press pressure in the press molding is in a range of 20 to 100 t.   The perforated magnetic shield sheet according to any one of claims 1 to 3 and a coil having a terminal protruding in the thickness direction are joined in a state where the terminal is inserted through the hole of the perforated magnetic shield sheet. Coil with perforated magnetic shielding sheet.

Images