JPH05251245A - Shrinkable covering material, inductance element, wiring material and/or circuit component - Google Patents

Abstract

PURPOSE:To prevent an object from leaking a magnetic flux and absorbing or radiating noises by a method wherein the above object is covered with a shrinkable covering material which contains magnetic substance. CONSTITUTION:A choke coil 1 is covered with a heat-shrinkable tube 2A which contains magnetic substance. The heat-shrinkable tube 2A is heated at a prescribed temperature to shrink, whereby a heat-shrinked tube 2B is made to cover the longitudinal circumferential surface of the choke coil 1 coming into close contact with it, and thus an inductance element 6 (choke coil) is obtained. As this shrinkable covering material contains magnetic substance and is high in heat-shrinkable properties, it is capable of easily covering a prescribed object taking advantage of its shrinkable properties. The covering material forms a closed circuit with magnetic substance contained in it to prevent the object from leaking a magnetic flux and radiating or absorbing noises.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shrinkable covering material, an inductance element covered with the shrinkable covering material, and a wiring material and / or a circuit component.

[0002]

2. Description of the Related Art Among various electronic devices including OA devices,
In order to suppress the alternating current, as shown in FIG. 17, the core 1
A choke coil 1 having a structure in which a coil 1a is wound around b is used (note that 61 is a terminal of the coil). FIG. 5 shows, as an example thereof, the choke coil 1 arranged in the computer body 8 of the personal computer by a broken line.

However, the choke coil 1 is
Although it has the advantage of being inexpensive, since an open magnetic path is formed as shown in FIG. 18, there is a large amount of leakage magnetic flux 66, which causes noise. That is, if the leaked magnetic flux enters another part of the electronic device or the inside of the other electronic device, a malfunction easily occurs.

As a measure for preventing the above-mentioned magnetic flux leakage,
As shown in FIG. 19, the coil portion 1a of the choke coil 1 is covered with a ring core 62 (or a ring cap) made of ferrite, and a closed magnetic circuit is formed in the ring core 62 so that the above-mentioned leakage magnetic flux passes through the ring core 62. Attempts are being made.

FIG. 19A shows a coil portion 1 of a choke coil 1.
FIG. 2B shows the state immediately before the ring core 62 is covered with a, and the choke coil with the ring core after covering the coil portion 1a of the choke coil 1 with the ring core 62, respectively.

However, in this case, the number of steps for assembling the choke coil 1 with the ring core 62 and the number of steps for adhering the ring core 62 to the choke coil 1 are required, which causes a high cost. Further, in some cases, because of the weight increase due to the ring core 62, it is necessary to provide the base portion 60 (or flange) as shown in the drawing to the choke coil 1, and there is a problem that the cost is further increased.

On the other hand, there is a problem due to the following noises in the lead wires connecting the electronic devices.

That is, the lead wire of electronic equipment such as office automation equipment is a portion that easily emits and absorbs particularly high frequency noise. Further, an AC adapter and a power cord for obtaining a DC power source from an AC power source are also portions that easily generate noise.

When noise enters the lead wire from the outside,
This is inconvenient because the original signal to be transmitted is modulated.
Further, if noise is emitted from the lead wire and enters the electronic device, it may cause a malfunction.

As a countermeasure against such noise, as shown in FIG. 20, a ring core 72 made of sintered ferrite powder is attached around the lead wire 77 to prevent noise emission and absorption.

The ring core 72 is made by sintering ferrite powder, but the sintered body of ferrite is brittle, and
The dimensional accuracy cannot be sufficiently obtained due to shrinkage during molding. Further, the ferrite sintered body has insufficient mechanical strength against external pressure due to its brittleness, and its shape cannot be changed, so that it cannot be said that it is suitable for being attached to a lead wire for use.

[0012]

SUMMARY OF THE INVENTION The present invention was made in view of the above circumstances. The first invention is to prevent leakage magnetic flux,
Moreover, it is an object of the present invention to provide a tough shrinkable covering material capable of surely preventing noise emission and absorption.

A second object of the present invention is to provide an inductance element in which leakage magnetic flux is reliably blocked, easily and at low cost.

A third object of the present invention is to provide a wiring member and / or a circuit component which can surely prevent noise radiation and absorption.

[0015]

That is, the first invention of the present invention relates to a shrinkable coating material containing a magnetic material, having shrinkability, and capable of coating a predetermined object by shrinkage.

A second aspect of the present invention relates to an inductance element having a structure in which a contractible coating material containing a magnetic material covers at least a coil portion in a contracted state.

Further, a third aspect of the present invention relates to a wiring material and / or a circuit component having a structure in which a shrinkable coating material containing a magnetic material covers the surface of the wiring material and / or the circuit component in a contracted state. ..

Examples of the present invention will be described below.

First, embodiments of the first and second inventions will be described (however, common portions to those of the conventional example shown in FIG. 17 and the like are designated by common reference numerals, and description thereof may be omitted).

FIG. 1 is a perspective view showing a state immediately before the choke coil 1 is covered with the heat-shrinkable tube 2A containing a magnetic material.

The choke coil 1 may be a usual choke coil, and has a structure in which a coil 1a is formed by winding a conductor wire around a core 1b having an I-shaped cross section.

As the material of the core 1b, a Mn--Zn ferrite, a sintered body of Ni--Zn ferrite, a carbonyl iron powder compact, or the like is preferably used.

FIG. 2 shows a heat-shrinkable tube containing a magnetic material in the choke coil 1 (hereinafter, simply referred to as a heat-shrinkable tube).
It is an expanded sectional view of the state where 2A was covered.

The heat shrinkable tube 2A is made of polyvinyl chloride,
For example, ferrite powder particles 4 having a magnetic permeability of about 500 are uniformly dispersed in a base material 3 such as ethylene-propylene elastomer or silicone rubber (rubber of organosiloxane) at a weight ratio of 50%.

As the ferrite powder, powders of Mn-Zn type ferrite, Ni-Zn type ferrite and Mg-Zn type ferrite can be preferably used, and in addition, sendust, permalloy powder and the like can be used.

As the resin material, polypropylene, polyamide, polyphenylene sulfide, polyethylene,
Polystyrene, ethylene-vinyl acetate copolymer, ethylene ethyl acrylate, 6-nylon, 6,6-nylon, 6,10-nylon, 11-nylon, 12-nylon,
A material made of a thermoplastic resin such as polyethylene terephthalate or polybutylene terephthalate can be used.

The magnetic powder such as ferrite magnetic powder is 50% by weight in the molded tube for the magnetic permeability of the tube.
It is desirable that the above content be contained, and 70 to 90% by weight is further desirable.

The method for producing the above-mentioned tube molded body will be described with reference to a specific example. First, a raw material composition containing iron oxide as a main component is crushed by a ball mill, and additives (binder, antifoaming agent, lubricating agent) are added thereto. Agent, plasticizer) while adjusting the slurry concentration to prepare a slurry composition. The respective compositions of the raw material composition and the additives are shown below.

Raw material composition Fe ₂ O ₃ 49.72mol% ZnO 31.70mol% NiO 9.11mol% CuO 9.47mol% Additive binder (polyvinyl alcohol) 120 liter antifoaming agent 1 liter lubricant 8.5 Kg plasticizer 1.0 Kg slurry concentration ( Raw material composition%) 55%

The slurry composition thus prepared is spray-dried to give an almost spherical granulated powder. Then, this granulated powder is fired while being stirred at a temperature of about 1050-1100 ° C. to obtain a substantially spherical Ni—Zn—Cu-based ferrite powder (particle size = several μm to several tens μm).

In addition, the following Mg-Zn system, Mn-Zn
It is possible to produce a tube molded body using a ferrite powder of the system. Mg-Zn system: Fe ₂ O ₃ 48.0 mol% MgO 20.5 mol% CuO 7.5 mol% ZnO 24.0 mol% Mn-Zn system: Fe ₂ O ₃ 53.0 mol% MnCO ₃ 34.0 mol% ZnO 13.0 mol%

The heat-shrinkable tube 2A according to this embodiment is formed into a tube shape, for example, by adding 50 parts by weight of the above Ni-Zn-Cu ferrite powder to 50 parts by weight of the above resin material, kneading, and extruding this. And cut into a predetermined length.

Next, the heat-shrinkable tube 2A is heated to a predetermined temperature to shrink it, and as shown in the perspective view of FIG. 3 (a) and the enlarged sectional view of FIG. 3 (b), the height of the choke coil 1 is increased. The circumferential surface in the direction is covered with the contracted heat-shrinkable tube 2B so that the inductance element 6 (choke coil) is completed.

The coating with the heat-shrinkable tube 2B is
As shown in FIG. 3, the upper and lower parts of the core part 1b of the choke coil 1 may be covered, or only the region of the coil part 1a may be covered.

FIG. 4 shows the coil portion 1a of the choke coil 1.
FIG. 3 is a schematic enlarged cross-sectional view showing a magnetic flux generated when a current is supplied to the.

The heat-shrinkable tube 2B is made of ferrite powder particles 4
Since the magnetic flux has a constant magnetic permeability due to the existence of the magnetic field, the magnetic flux forms the closed magnetic path 5 passing through the tube 2B and its vicinity, and the formation of the open magnetic path 65 as shown in FIG. 18 is suppressed. Therefore, the radiation of the leakage magnetic flux is effectively prevented (the amount of radiation becomes, for example, 1/2 or less), and the malfunction of the device due to the leakage magnetic flux is not caused.

Further, since the heat-shrinkable tube 2B can be manufactured to have a thickness of about 0.5 mm, it is light in weight and is held in close contact with the circumferential surface of the coil, so that it is not necessary to provide the pedestal 60 as shown in FIG. Further, the work of covering with the tube 2B is also easily performed by heating with hot water or the like, and the small-sized inductance element 6 is manufactured at low cost.

By the way, in the choke coil with a ring core shown in FIG. 19 (b), the cost of parts for each ring core and base is
In the inductance element 6 according to the present example, the cost of the heat-shrinkable tube parts is 0.5 to 3 yen, and the required number of assembly steps is 10 to 20 yen.
It takes less than 0.1 minutes.

Next, FIG. 5 shows a personal computer to which the present invention is applicable and its peripheral equipment separated from each other. The personal computer comprises an input keyboard 7, a computer main body 8, a floppy disk drive 9, a display 10 and a printer 11, which are electrically connected by lead wires 12, 13, 14, 15.

Immediately after the input side terminal from the keyboard 7 in the computer main body 8 and immediately before the lead wire connection terminal on the output side to the display 10 and the printer 11, the inductance element 6 having the structure shown in FIG. 3 is arranged. ..
This prevents the passage of high frequency noise,
Due to the action of the closed magnetic circuit 5 in FIG. 4, the leakage magnetic flux does not enter other elements in the computer main body 8 or other devices,
Malfunction is prevented.

Further, since the inductance element 6 can be miniaturized as described above, the computer main body 8 can be miniaturized as compared with the case of using the conventional choke with a ring core shown in FIG. 19 (b).

Next, an example in which a heat shrinkable tube is produced by setting the ferrite powder blending amount in two ways will be described. Ni-Zn ferrite powder with a permeability of about 500 to polyvinyl chloride (maximum particle size 100 μm, minimum particle size 1 μm, average particle size 40 μm
50% or 90% by weight of the ferrite powder pulverized into 1) was added, kneaded, and extruded to obtain two kinds of heat shrinkable tubes 1A. The permeability of the former weight ratio tube was about 2, and that of the latter weight ratio tube was about 15.

The higher the ferrite powder blending ratio, the greater the shielding effect, and the lower the ferrite powder blending ratio, the greater the shrinkability.

As described above, the heat-shrinkable tube 1A according to this example is produced by kneading a resin material containing ferrite powder, extruding the resin material into a tube shape, and cutting it into a predetermined size. As well as showing sufficient magnetic permeability as part of the core, it is thin, lightweight and has sufficient strength,
It has toughness, and is easily manufactured at low cost.

Further, the inductance element according to the present example is
Since the light-weight heat-shrinkable tube 1A described above is simply covered by covering the choke coil 1 and shrinking to form the covering tube 1B, the assembly is easy and the manufacturing can be performed at low cost. It can also be made small. Further, a closed magnetic circuit is formed by the action of the ferrite powder particles in the heat-shrinkable tube, the leakage magnetic flux is blocked, and the malfunction of the device due to this is prevented.

FIG. 6 shows a heat-shrinkable tube 22A made in the same manner as in the above-mentioned example in the transformer 21 with a gap.
The state just before covering is shown. Then, after covering with the heat-shrinkable tube 22A, it is heated and shrunk in the same manner as in the above example, and as shown in FIG. 7, the shrunk heat-shrinkable tube 22B covers the peripheral surface of the transformer 21.

In the transformer with a gap 21, the core 21c is provided with a gap 21d, thereby increasing the magnetic resistance of the core and increasing the DC superposition inductance. In the figure, 21a is a primary coil and 21b is a secondary coil.

With the transformer 21 with a gap alone (ie,
Without the heat-shrinkable tube 22B), a leakage magnetic flux 26 indicated by an imaginary line is generated from the edge of the gap 21d, which reduces the inductance.

By covering the transformer 21 with a gap with the heat-shrinkable tube 22B, as shown in FIG. 7, the ferrite powder particles 24 dispersed in the synthetic resin matrix 23 of the heat-shrinkable tube cause the magnetic flux 25 shown by the solid line to be reduced. , Heat shrink tube 22
Pass through B.

As a result, the leakage magnetic flux 26 is eliminated and the inductance is prevented from decreasing. At the same time, it is needless to say that the malfunction of the device due to the leakage magnetic flux can be prevented as in the above example.

Even in a coil with a gap, the same effect as described above can be obtained by covering with a heat-shrinkable tube.

Next, an embodiment of the third invention will be described.

FIG. 8 schematically shows a data processing system to which the present invention is applicable, in which data can be stored from one personal computer as a master to another personal computer as a slave. ..

In the figure, 33A is the main body of the base unit, 34A is the same keyboard, 35A is the same display, 36A is the same power cord, 33B is the main unit of the handset, 34B is the same keyboard, 35B is the same display, and 36B is the same. It is the same power cord.

Both main bodies 33A and 33B are connected by a lead wire 37, and the operator operates the keyboard 34A of the master unit, whereby the same data as the data stored in the master unit main body 33A is simultaneously stored in the main slave unit 33B. Is stored.

As shown in the enlarged view of FIG. 10, the line connecting cord 37 and the power cord 36 in which the conductor wire 38 is covered with an insulator 39.
A heat shrink tube 32B is attached to A and 36B.

The heat-shrinkable tube 32B is attached so as to surround the lead wire 37 or the power supply cords 36A and 37B, respectively. The heat-shrinkable tube 32B is made of ferrite powder particles in a base material 33 of synthetic resin.
34 is a molded body that is uniformly dispersed.

The heat-shrinkable tube 32B is attached to the lead wire or the power cord as follows.

That is, as shown in FIG. 9, the lead wire 37 or the power cords 36A and 36B are inserted into the heat-shrinkable tube 32A manufactured in the same manner as in the first invention.

Then, the heat-shrinkable tube 32A is heated and shrunk in the same manner as in the second embodiment of the present invention.
0, as shown in FIG. 11, lead wire 37 or power cord 36
Stick and fix to the peripheral surface of A and 36B. Heat shrink tube 32
B is preferably coated over the entire length of the lead wire 37 or the power cords 36A, 36B in the length direction.

The heat-shrinkable tube 32B forms the closed magnetic path 5 in the same manner as in the inductance element 6 of the second invention, and noise is removed by this (see FIG. 4).

FIG. 12 shows this action as an equivalent circuit, and the lead wire or the power cord is surrounded by the heat-shrinkable tube 32B to have an inductance, and the inductor 40 is constituted. As a result, it becomes a high-frequency noise filter, absorbs line noise, and covers the entire lead wire to obtain a magnetic shield effect, thereby blocking electromagnetic noise.

Therefore, a signal containing no noise is sent to the slave unit main body 33B, and the predetermined data is accurately stored. Also, noise to or from the power supply 40 can be blocked.

As described above, the wiring material such as the lead wire and the power cord according to this embodiment is manufactured by inserting the above-mentioned wiring material into the heat-shrinkable tube and shrinking the tube, so that the cost is low. Can be manufactured in. Furthermore, a closed magnetic circuit is formed by the action of the ferrite powder particles in the heat-shrinkable tube, noise is absorbed, malfunction of the device due to noise is prevented, and electromagnetic noise can be blocked.

Moreover, since the heat-shrinkable tube is a molded body having a base material of synthetic resin, it has toughness and flexibility and is convenient as a covering material for wiring materials such as lead wires and power cords. is there.

FIG. 13 shows a state immediately before the resistance element 41 is inserted into a heat-shrinkable tube 42A manufactured in the same manner as in each of the above-described examples. After insertion, the heat-shrinkable tube 42A is heated and shrunk in the same manner as in each of the above-described examples, and the shrunk heat-shrinkable tube 42B is shrunk as shown in FIG.
The main body 41a of the resistance element 41 and part of the leads 41b, 41b on the main body side are covered with.

Also in this example, as in the example of FIGS. 8 to 12, the ferrite powder particles 44 dispersed in the synthetic resin matrix 43 prevent noise emission and absorption.

The coating with the heat-shrinkable tube as described above can be similarly applied to a circuit component such as a capacitor or a semiconductor component other than the resistance element.

FIG. 15 shows a state immediately before the AC adapter 51 is inserted into a heat-shrinkable tube 52A manufactured in the same manner as in each of the above examples. After the insertion, the heat-shrinkable tube 52A is heated and shrunk in the same manner as in each of the above examples, and the shrunk heat-shrinkable tube is shrunk as shown in FIG.
The AC adapter 51 is covered with 52B.

In this example, the AC adapter 51
It is desirable that the AC power supply cord 57 and the DC supply lead wire 56 are also covered with the heat-shrinkable tube 52B over the entire length direction.

Also in this example, as in the example of FIGS. 8 to 14, the ferrite powder particles 54 dispersed in the synthetic resin matrix 53 prevent noise emission and absorption.

Although the embodiments of the present invention have been described above, various modifications can be made to the above embodiments based on the technical idea of the present invention.

For example, the above-mentioned inductance element and wiring material can be applied to various electronic devices other than a personal computer, and the same effect can be obtained. Further, the present invention can be applied to elements and harness materials other than the above. The magnetic material may be an appropriate magnetic material such as sendust or permalloy other than ferrite, and may be in the form of flakes, fibers, etc. other than powder. You can change the type of shrinkable resin material,
Its shape can also be changed.

[0074]

Since the shrinkable coating material based on the first invention contains a magnetic material and has a shrinkability, a predetermined object can be easily coated due to this shrinkability, and the magnetic material contained therein is contained. By this, a closed magnetic circuit can be formed to prevent leakage magnetic flux from the object, and also prevent noise emission and absorption. In addition, a magnetic material can be added to the shrinkable material, kneaded, and easily molded by extrusion molding or the like, and a covering material that is tough and has a low manufacturing cost can be provided.

The inductance element based on the second invention is
Since the shrinkable coating material according to the first aspect of the invention covers at least the coil portion in a contracted state, a closed magnetic circuit is formed by the magnetic material in the coating material, thereby preventing leakage magnetic flux. Therefore, malfunction of the electronic device due to the leakage magnetic flux is prevented. Further, the covering material can be made lightweight, and the manufacturing cost can be reduced because the inductance element is small.

The wiring material and / or the circuit component based on the third invention are covered with the shrinkable coating material based on the first invention in a contracted state. Is added to prevent noise emission and contraction. As a result, a noise-free signal or current is supplied to the electronic device or other circuit component, and normal operation is always guaranteed.

[Brief description of drawings]

FIG. 1 is a perspective view showing a heat-shrinkable tube containing a magnetic material and a choke coil body separately in an embodiment of the first and second inventions.

FIG. 2 is an enlarged cross-sectional view showing a state in which a choke coil body is covered with a heat-shrinkable tube containing a magnetic material in the examples of the first and second inventions.

FIG. 3 shows an inductance element according to the second invention,
FIG. 3 (a) is a perspective view and FIG. 3 (b) is an enlarged sectional view.

FIG. 4 is a schematic enlarged cross-sectional view showing magnetic flux in the same inductance element.

FIG. 5 is a perspective view showing separately the devices constituting the personal computer.

FIG. 6 is a perspective view showing a heat-shrinkable tube containing a magnetic material and a transformer with a gap, which are separated from each other, in Examples of the first and second inventions.

FIG. 7 is a schematic enlarged cross-sectional view showing a magnetic flux of a transformer with a gap according to an embodiment of the second invention.

FIG. 8 is a schematic perspective view of a data processing system according to an embodiment of the third invention.

FIG. 9 is a perspective view showing a heat-shrinkable tube containing a magnetic material and a lead wire or a power cord separately in an embodiment of the third invention.

FIG. 10 is an enlarged cross-sectional view orthogonal to the central axis of the lead wire or the power cord according to the embodiment of the third invention.

FIG. 11 is an enlarged cross-sectional view passing through the center axis of the lead wire or the power cord.

FIG. 12 is a schematic circuit diagram showing FIG. 11 as an equivalent circuit.

FIG. 13 is a perspective view showing a heat-shrinkable tube containing a magnetic material and a resistance element separately in an embodiment of the third invention.

FIG. 14 is an enlarged cross-sectional view of a resistance element in a covered state according to an embodiment of the third invention.

FIG. 15 is a perspective view showing a heat-shrinkable tube containing a magnetic material and an AC adapter separately from each other in an embodiment of the third invention.

FIG. 16 is a sectional view of the AC adapter according to the third embodiment of the present invention in a covered state.

[Fig. 17] Conventional choke coil (inductance element)
FIG.

FIG. 18 is an enlarged cross-sectional view showing a magnetic flux of the choke coil.

19 shows another conventional choke coil (inductance element), FIG. 19 (a) is a perspective view showing the choke coil body and the ring core separately, and FIG. 19 (b) is a perspective view of the assembled inductance element. It is a figure.

FIG. 20 is a perspective view showing a usage state of a conventional ring core for wiring material.

[Explanation of symbols]

1 Choke coil 1a Coil part 2A, 22A, 32A, 42A, 52A End-shrinkable heat-shrinkable tube with magnetic material 2B, 22B, 32B, 42B, 52B Shrinkable heat-shrinkable tube with magnetic material 3, 23, 33, 43 , 53 Base material of synthetic resin 4, 24, 34, 44, 54 Ferrite powder particles 5, 25 Magnetic flux 6 Inductance element 12, 13, 14, 15, 37, 56 Lead wire 21 Transformer with gap 21a Primary coil 21b Secondary coil 21d Gap 26, 66 Leakage magnetic flux 36A, 36B, 57 Power cord 41 Resistor element 51 AC adapter

Claims (3)

[Claims] 1. A shrinkable coating material containing a magnetic material, having shrinkability, and capable of coating a predetermined object by shrinkage. 2. An inductance element having a structure in which a contractible coating material containing a magnetic material covers at least a coil portion in a contracted state. 3. A wiring material and / or circuit component having a structure in which a shrinkable coating material containing a magnetic material covers the surface of the wiring material and / or circuit component in a contracted state.