JPH11176677A - Cordless power station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To materialize downsizing by dispensing with a battery, at the section on output side. SOLUTION: This cordless power station includes two coils which are opposed to each other across space, which constitute a primary coil 21 with a section 20 on input side of power, and constitute a secondary coil 11 with a section 10 on the other output side, and when transmitting power with no contact, making use of the electromagnetic induction work generated between these opposed oil, and the section 10 output side outputs power, being equipped with a charge circuit by a small-sized circuit part 14 connected with the secondary coil 11, on the face opposite to the face where the primary coil 21 and the secondary coil 11 are opposed, and at least either the primary coil 21 and the secondary coil 11 opposed to each other is provided with the ferrite core 12 of a soft magnetic material layer, on the face opposite to the face where these two are opposed to each other. For the section 10 on output side which receives power from the primary coil 21, it will do to omit the ferrite core 12, making the secondary coil 11 one to constitute it in minimum, and besides, providing the soft magnetic material layer outside the primary coil 21 of the section 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention includes two coils which face each other through an air gap and constitute a primary coil on the input side of power and a secondary coil on the other output side. The present invention relates to a cordless power station that transmits electric power in a non-contact manner by using an electromagnetic induction effect generated between coils, and particularly to a cordless power station that can reduce the size of an output side.

[0002]

2. Description of the Related Art Conventionally, in this type of cordless power station, non-contact power transmission of 1 watt (W) or more has been realized in many cases. Is designed in consideration of efficiency or heat generation. Therefore, the structure of the cordless power station has a large shape. Also, there is no contactless power transmission at about several tens of milliwatts, and a small button-type battery must be built in. For this reason, at present, the shape and size of the cordless power station are determined by the shape and size of the built-in battery.

As described above, when a battery is built-in, an open / close lid for maintenance is required, so that the degree of freedom in miniaturization design of the cordless power station is lost.

[0004] On the other hand, there are many small mobile devices or movable toys that use a small amount of electric power received with a built-in small battery for lighting or motive power, and these devices or toys are desired to be further downsized. Therefore, miniaturization is attempted by eliminating batteries.

[0005]

In the above-mentioned conventional cordless power station, when the size is reduced, it is necessary to reduce the size of the coil and the soft magnetic material for transmitting electric power in a non-contact manner. However, downsizing has the following two problems.

One is that when only one secondary side coil is provided on the output side, the transmission efficiency is deteriorated as compared with the case where a plurality of secondary side coils are used.

[0007] The reason is that a plurality of, for example, two,
This is because the efficiency is improved by connecting the magnetic flux in one direction by connecting in series reverse pitch, but the leakage of the magnetic flux increases in the case of one.

Another problem is that when the sizes of the coil and the soft magnetic material are reduced, for the same reason as described above,
The leakage of magnetic flux increases, the efficiency deteriorates, the loss increases, and the temperature rises.

It is an object of the present invention to provide a cordless power station which solves the above-mentioned problems and which does not require a battery at the output side and which can be miniaturized.

[0010]

SUMMARY OF THE INVENTION A cordless power station according to the present invention is intended for a small power of several tens of milliwatts in order to reduce the size of a coil and a power supply to such an extent that some problems such as efficiency reduction, heat generation and noise can be ignored. The size of the soft magnetic material is made as small as possible.

The present inventors have conducted intensive studies on the electrification of small devices which cannot be electrified because of their small size, and on the means for further miniaturizing the small electronic electric devices. I came up with contact power transmission,
The output side of the cordless power station has been downsized.

That is, a cordless power station according to the present invention includes two coils that face each other through an air gap and that constitute a primary coil on the input side of power and a secondary coil on the other output side, In a cordless power station that transmits power in a non-contact manner by utilizing an electromagnetic induction effect generated between the opposed coils, the secondary coil is provided on a surface of the output side opposite to a surface facing the two coils. A charging circuit is provided by a small circuit component to be connected to output power, and at least one of the opposed coils is provided with a soft magnetic material layer on a surface opposite to a surface opposed to the two coils by a soft magnetic member. It is characterized by that.

The basic technology for wirelessly transmitting power is disclosed in, for example, Japanese Patent Application Laid-Open Nos. Hei 7-231586 and Hei 8-1483 filed by the present applicant.
No. 60, "cordless power station". In this device, electromagnetic induction is used to transmit power from a power transmission side to a power reception side in a non-contact manner.

[0014] Separately, in order to prevent deterioration in efficiency due to miniaturization, the relative relationship between the shape of the coil and the soft magnetic material was also specifically examined.

As a result of this study, the above-mentioned means has made it possible to design a small-power, small-sized electronic / electric device incorporating a non-contact type charger combining a non-contact power transmission coil and a soft magnetic material.

[0016]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view for explaining an embodiment of the present invention, FIG. 2 is a circuit diagram of FIG. 1, and FIG.
FIG. 3 is an exploded perspective view for explaining the output side portion 10 of FIG. 1.

As shown in FIG. 1, in the cordless power station, the output portion 10 includes a secondary coil 11, a ferrite core 12 of a soft magnetic layer, and a circuit board 1.
3, and circuit components 14 mounted on the circuit board 13. These components are housed in the housing 15, and the secondary coil 11 performs an electromagnetic induction action between the primary coil 21 and the input side portion 20. Power supply.

As shown in the circuit diagram of FIG. 2, the output section 10 forms a contactless charger. That is, the circuit component 14 includes a resonance capacitor 17 connected in parallel to both ends of the secondary coil 11, and a series circuit of a rectifying Schottky diode 18 and a smoothing capacitor 19 further connected in parallel. It is assumed that output power is taken out from both ends of 19. On the other hand, in the input part 20, the input voltage is frequency-converted by the frequency conversion circuit 22 and supplied to the primary coil 21.

Next, the configuration of the output portion 10 will be described in detail with reference to FIG. 3 and FIGS.

As shown in FIG. 3, the output side portion 10 is housed inside a cylindrical housing 15, and the secondary side coil 1
Reference numeral 1 denotes one planar spiral coil, but any other type of coil or a flexible pattern may be used as long as it is suitable as a secondary coil. Also,
The winding may be a single winding or a double winding or more.

The ferrite core 12 and the circuit board 1
3 has a disk shape. Resonant capacitor 1 constituting circuit component 14 mounted on circuit board 13
7. The rectifying Schottky diode 18 and the smoothing capacitor 19 are of a chip type for miniaturization. Of course, it is not limited to the chip type.

As shown in FIG. 4, the secondary coil 11 is smaller than the periphery of the ferrite core 12 by 1 mm or more, that is, the outer diameter is reduced by 2 mm or more. The width is set to 1 mm or more. The outer window of 1 mm or more has the same outer diameter of the ferrite core 12 between 5 mm and 30 mm. 4A to FIG.
In (B) and (C), the outer diameter dimension is substantially “１ ／”, “1”.
/ 6 "is a rear view from the side of the secondary coil when the ferrite cores 12, 12b, 12c are superimposed on the secondary coils 11, 11b, 11c. The road is secured with a width of 1 mm or more.

The larger the passage width of the magnetic flux, the better.
As the size increases, the number of turns of the secondary coil 11 decreases and the inductance decreases, or the inner diameter decreases and the area of the inner window decreases, which causes a reduction in efficiency.

In the shape of the present embodiment, the maximum outer diameter of the ferrite core 12 which is a soft magnetic material layer is within 30 mm, which is generally the minimum diameter in a small device, and 3 mm.
If it exceeds 0 mm, the conventional multiple transmission method is superior. The minimum outer diameter is suitably 5 mm or more. The reason is that sufficient inductance cannot be obtained with an outer shape of 5 mm or less, and almost no inductance can be obtained with a diameter of 3 mm or less.

Next, the input side portion 20 which is electromagnetically coupled to the output side portion 10 will be described with reference to FIGS.

In the input-side portion 20 shown in FIG.
It is provided above and extracts the input power via the frequency conversion circuit 22 and transmits the power to the secondary coil 11 of the output side portion 10. The details of the illustrated input part 20 are described in Japanese Patent Application No. 9-2566 proposed by the present applicant.
No. 74 describes its structure and function.

The illustrated input portion 20 is provided with a plurality of spiral-type primary coils 21 over the entire surface of a flat pad 23 which is a soft magnetic layer.

The structure of the output side portion 10 and the input side portion 20 and the form of power transmission are set so that the gap between the secondary coil 11 and the primary coil 21 is 5 mm or less from the viewpoint of power transmission efficiency. Have been. As shown in FIG. 1, the output side portion 10 and the input side portion 20 are provided with ferrite on the outside of the secondary side coil 11 so that leakage of magnetic flux generated from the coil side is 40% or less. A soft magnetic layer such as the core 12 is mounted. This soft magnetic layer may be provided outside at least one of the secondary coil 11 and the primary coil 21.

The technology relating to this structure is described in, for example, Japanese Patent Application Laid-Open No. 8-148360 proposed by the present applicant.

As described in this publication, a soft magnetic member is made of a spinel type ferrite material (Mn-Z).
In the case of n-type), the optimum conditions are that the saturation magnetic flux density B is 300 mT or more, the magnetic permeability μ is 400 or more, and the electric resistance ρ is 1 kΩ-m or more.

As an optimum condition, the frequency used for power transmission is 500 kHz or more. Also,
The soft magnetic material layer made of the soft magnetic member has a thickness of 0.1 mm to 5.0 mm.
mm. That is, when the soft magnetic material layer has a thickness of 0.1 mm or more, the effect of capturing magnetic flux is recognized, but no increase in the effect is recognized even when the thickness is 5 mm or more. This is because the effect is reduced.

The circuit board may be a soft magnetic layer. As a result, the size can be further reduced. In the above description, the ferrite core as the soft magnetic layer is suitably a ferrite plate having a spinel structure, but may be another type of soft magnetic member, and the material is not limited to ferrite. In addition, the soft magnetic layer may have flexibility, and in this case, the soft magnetic layer can be in uniform contact with the surface of the curved input side portion together with the secondary coil.

When these soft magnetic layers have flexibility, they are formed using powder having at least one of flat, acicular and granular shapes as the soft magnetic member. The average particle size is 150 μm or less.

Next, referring to FIG. 6 with reference to FIGS. 1, 3 and 5, there is shown a small device incorporating the components of the output portion 10 of the cordless power station according to the present invention shown in FIG. A usage example will be described.

FIG. 6A shows a state in which the illumination marker 40 is placed on the surface of the map 30. Illuminated marker 40
Incorporates an output side portion 10 shown in FIG. 1 in which a light emitting diode is connected to the output. FIG.
As shown in (B), on the back of the paper map 30,
A pad 23 as shown in FIG. 5 to which power is input is provided. It is assumed that the thickness of the map 30 is within the range described above in order to obtain a sufficient amount of light.

Therefore, the pad 23 can be
The illuminated marker 40 located on the primary coil 21 has a built-in output part 10, which receives power transmitted from the input part 20 of the cordless power station including the primary coil 21 to emit a light-emitting diode, The surface of the map 30 can be illuminated. On the other hand, the illuminated marker 40a that is out of the position of the primary coil 21 cannot receive power transmission and cannot illuminate the surface of the map 30.

Although the map is depicted as a flat plate in the drawings, as described above, when the pad of the input side portion 20 and the soft magnetic layer of the illumination marker 40 are flexible, the primary side coil and Since both of the secondary coils can equally contact the curved surface, the range of use is expanded.

As another application field, a small device having a buzzer instead of a light emitting element at the output side can be produced. Furthermore, it is possible to run a radio-controlled vehicle with a built-in motor driven by the output power of the output part on a pad of a large input part.

In the above description, one secondary coil is provided to minimize the size of the output side portion. However, a plurality of secondary coils may be provided. Also, as mentioned above,
The shape of the primary side coil and the secondary side coil may be any of a spiral type and a meander type, but since at least one of them is a spiral type, transmission efficiency can be improved.

In the above description, the secondary coil is a flat spiral type. However, when the primary coil is a flat spiral type, the opposed secondary coil is preferably a flat meander type. This is an effective combination when the coils facing each other are of a plane meander type. The reason is that the magnetic fluxes generated from adjacent conductors are opposite to each other, so they strengthen each other, further suppress the electromagnetic noise to the surroundings, suppress the deterioration of the transmission characteristics due to displacement, and have a high degree of planar freedom. Because it is obtained.

On the other hand, when the coils facing each other are of a planar spiral type, when the air-core coils of a plurality of coils are densely located on the same plane, the amount of magnetic flux increases accordingly, so that the coils are kept thin. Transmission power can be increased. On the other hand, if the coils facing each other are planar spiral type and have the same diameter, there is a problem that the transmission power of one secondary coil becomes zero when the center axis of the coil is shifted by the radius of the primary coil. Occurs.

In the above description, the housing on the output side has a cylindrical shape, and the internal components have been illustrated in the form of a disk. However, these shapes are not limited to circular shapes.

[0044]

As described above, according to the present invention, it is possible to realize a configuration and a structure that can reduce the size of the output side portion by non-contact power transmission by limiting the power to a small amount of power. And the degree of freedom in miniaturization design can be improved by eliminating the need for batteries in low-power electronic devices.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram showing an embodiment directed to FIG. 1;

FIG. 3 is an exploded perspective view illustrating an embodiment of an output side portion in FIG. 1;

FIG. 4 is an explanatory diagram showing one form of a partial positional relationship in FIG. 1;

FIG. 5 is a plan view showing one form of an input part in FIG. 1;

FIG. 6 is an explanatory diagram showing one embodiment of a use mode of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Output part 11 Secondary coil 12 Ferrite core of soft magnetic material layer 13 Circuit board 14 Circuit parts 15 Housing 17 Resonant capacitor 18 Diode 19 Smoothing capacitor 20 Input part 21 Primary coil 22 Frequency conversion circuit

Claims (18)

[Claims] An electromagnetic induction generated between two coils facing each other through an air gap and comprising a primary coil on a power input side and a secondary coil on another output side. In a cordless power station that transmits power in a non-contact manner by utilizing a function, a charging circuit is formed by a small circuit component connected to the secondary coil on a surface opposite to a surface facing the two coils in the output portion. A cordless power station comprising: a power output unit; and a soft magnetic layer made of a soft magnetic member provided on a surface of at least one of the opposed coils opposite to a surface facing the two coils. . 2. The cordless power station according to claim 1, wherein at least one of the opposing coils is a planar spiral coil. 3. The cordless power station according to claim 1, wherein at least one of the opposed coils is a meander type coil. 4. The cordless power station according to claim 1, wherein an input side of the opposed coil is constituted by one of a plane meander type coil and a plane spiral type coil, and an input side of the plane meander type coil is provided. In some cases, the cordless power station has an output side formed by a flat spiral coil. 5. The cordless power station according to claim 1, wherein the soft magnetic layer is formed of a spinel type ferrite plate. 6. The cordless power station according to claim 1, wherein the soft magnetic material layer has flexibility. 7. The cordless power station according to claim 6, wherein the soft magnetic layer having flexibility is formed using powder having at least one of a flat shape, a needle shape, and a granular shape. A cordless power station characterized by the following. 8. The cordless power station according to claim 7, wherein the powder has a mean particle size of 150 micrometers (μm) or less. 9. The cordless power station according to claim 1, wherein the soft magnetic member is a spinel type ferrite material (Mn-
A cordless power station, which is a Zn-based power station, has a saturation magnetic flux density B of 300 mT or more and a magnetic permeability μ of 400 or more. 10. The cordless power station according to any one of claims 1 to 5, wherein
The soft magnetic member is made of a spinel-type ferrite material (Mn).
A cordless power station, wherein the cordless power station is a Zn-based) and has an electric resistance ρ of 1 kohm-meter (kΩ-m) or more. 11. The cordless power station according to any one of claims 1 to 5, wherein
The soft magnetic member is made of a spinel-type ferrite material (Mn).
-Zn) and the frequency used for power transmission is 5
A cordless power station characterized by being at least 00 kilohertz (kHz). 12. The cordless power station according to claim 1, wherein the soft magnetic layer constituting the soft magnetic member has a thickness of 0.1 mm to 5.0 mm. A cordless power station having a thickness in the range of millimeters (mm). 13. The cordless power station according to claim 1, wherein the soft magnetic layer constituting the soft magnetic member includes both the primary coil and the secondary coil. A cordless power station comprising: a core mounted on an outer portion of a portion formed by the core; and a leakage of magnetic flux generated from the inside of the core is reduced to 40% or less. 14. The cordless power station according to claim 1, wherein a gap between the input side portion and the output side portion is in a range from 0 mm (mm) to 5 mm (mm). A cordless power station, characterized in that: 15. The cordless power station according to claim 1, wherein the soft magnetic member on the output side has a specific resistance of 1000 megaohm-meter (MΩ-m) or more. A cordless power station comprising: a soft magnetic layer constituting a circuit board on an output side portion. 16. The cordless power station according to claim 1, wherein the output side portion is reduced in size by reducing the number of coils to one. station. 17. The cordless power station according to any one of claims 1 to 15, wherein the soft magnetic member is provided only on the input side, and the output side is downsized. Characterized cordless power station. 18. The cordless power station according to claim 1, wherein an outer shape of a secondary coil of the output side portion is the soft magnetic material provided in the output side portion. Smaller than the outer shape of the layer,
A cordless power station that is at least one millimeter (mm) inside.