JP2011238784A - Flat coil and electromagnetic energy converter using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flat coil with a small thickness in the axial direction and an electromagnetic energy converter using the same that are satisfactorily applicable to a non-contact charging system for portable devices.SOLUTION: An insulation strand wire is arranged side by side with another within one plane and then wound so as to form a spiral-spring shaped, planar multi-layer and multi-wire coil consisting of insulation strand wires as many as greater than a value obtained by dividing a square of "a conductor diameter required for a given allowable current value" by "a conductor diameter of the insulation strand wire". The planar multi-layer and multi-wire coil is stacked on another to form two stacked coils as shown in FIG. 1. The insulation strand wires constituting each of the two stacked coils are connected in parallel inside the respective coil and the two stacked coils are serially connected at the innermost circumference thereof so as to form one coil wire whose terminals are positioned at the outermost circumference of the two stacked coils. Preferably, the planar multi-layer and multi-wire coil has a cross section pressure-deformed in the coil axial direction so as to have a thickness equal to or greater than "π/4" times an outer diameter of the insulation strand wire constituting the coil.

Description

  The present invention relates to a flat coil having a small axial thickness suitable for a non-contact charging system used for a cordless telephone or a portable device (for example, a cellular phone, a digital camera, a portable game device). It is about.

In recent years, devices using an “electromagnetic induction action” in which an induced electromotive force is generated in a separate coil by using a magnetic flux generated by a current flowing in the coil has been widely used.
One of them is a contactless charging system used for a cordless phone, a mobile phone, a digital camera, a portable game device, and the like.

For example, Patent Document 1 discloses a charger structure using an electromagnetic induction coil as shown in FIG. 3 for transmitting electric power from a charging part to a charged part without contact via a metal contact by electromagnetic induction. It has been introduced.
The charging part of the non-contact charger shown in FIG. 3 is configured by winding a coil 12 for power transmission around a coil bobbin 11, inserting a core 13 into the coil bobbin 11, and then putting them in a casing 14. . The charged portion is configured by winding a power receiving coil 16 around a coil bobbin 15 and placing it in a housing 17.
A charging circuit is formed by bringing the charging unit and the charged unit configured as described above close to each other, and power transmission is performed.

Recently, however, the demand for compactness of these charging systems and the like has increased further. For this reason, it has been considered to reduce the coil volume by reducing the insulated wire (conductor) used for the coil. This method could not be adopted because the heat generation was so high.
In addition, in a non-contact charger, the smaller the distance between the power transmission coil that receives and receives the magnetic flux and the power receiving coil, the better the efficiency.Therefore, a flat coil with a thin axial thickness, which is considered advantageous in this respect, is required in designing. It was desired.
For this reason, flattening of a coil wound with as thick a conductor as possible has become an urgent issue.

By the way, it goes without saying that the flat multilayer coil having the smallest axial thickness is a coil in which insulated wires are wound in multiple layers in a row. However, as shown in FIG. Since the portion 19 is located on the innermost circumference of the coil and the winding end wire portion 20 is located on the outermost circumference of the coil, the winding start wire portion 19 is led out to the outside of the coil (outside the outer circumference) as a lead wire. In order to achieve this, it is necessary to guide the winding start wire portion to the outside of the coil so as to cross the coil end face.
Therefore, the thickness of the coil is unnecessarily increased by the wire diameter of this “winding start wire portion that crosses the coil end face” (that is, the diameter of the insulated wire), resulting in a coil with insufficient conductor density. There was a problem.

  Therefore, Patent Document 2 discloses a coil winding frame 23 having a “frame (flange) 22 provided with a slit 21” that can slide in the winding axis direction as shown in FIG. In addition, the insulated wire is wound in multiple layers by aligning windings so that the winding start wire portion 24 of the insulated wire remains with a sufficient length outside through the slit 21 provided in the slidable frame 22. After the winding end wire portion 25 is left on the outermost periphery of the coil and on the side where the slidable frame 22 is located, the slidable frame 22 is slid by one insulated wire outward. The space 26 is opened between the coil end surface and the frame surface, and the winding start wire portion 24 of the insulated wire left in the space 26 is further wound in multiple layers to thereby end the coil end surface. The winding start end is brought to the outermost periphery of the coil without crossing the coil involuntarily. Where obtained by a method that shows the distal end of the fit line portion), winding-start wire portion and the winding end wire part of the coil both high aligned multilayer wound coil of conductor density derived from the outermost periphery has been proposed.

  However, even the above-mentioned aligned multilayer winding coil disclosed in Patent Document 2 cannot be made thinner than twice the outer diameter of the insulated wire using the axial thickness (for two insulated wires). There was a limit.

JP 9-121481 A JP 58-51502 A

  The present invention has been made in consideration of the above-described circumstances, and has a conductor cross-sectional area larger than an insulated wire having a conductor diameter capable of flowing a current required for a coil (allowable current) and a shaft. It is to provide a thin multilayer wound flat coil whose directional thickness is thinner than twice the outer diameter of the insulated wire (for two insulated wires).

The present inventor has made various studies in order to solve the above problems, and has obtained the following knowledge.
That is, when a single coil of a spiral spring is manufactured by winding a single row of insulated wires around a winding frame, the obtained single coil has an inner diameter portion (the axis of the winding frame exists) as shown in Patent Document 2 above. The “disc-shaped gap portion in which no insulated wire exists” is formed in the portion).
Therefore, as shown in FIG. 1, two such single-row multi-layered coils (single coil) 1 in the form of a spiral spring are overlapped, and both are formed in the “disk-shaped air gap where there is no insulated wire” 2 at the inner diameter of the coil. When the winding start wire portions of the coils are connected in series (reference numeral 3 indicates a connection portion) so that current flows through the two coils in the forward direction, both ends of the insulated wires constituting the coils (relief) The thin flat coil having a thin axial thickness can be obtained very easily.

However, in this case, the thickness of the flat coil in the axial direction cannot be made smaller than the dimension of two insulated wires (dimension twice the outer diameter of the insulated wires).
However, after preparing an insulated wire (insulated wire strand) having an outer diameter smaller than “insulated wire having a conductor diameter necessary to achieve a set allowable current value” as an insulated wire constituting the coil As shown in FIG. 2, a plurality of insulated wire strands are stacked in multiple layers and wound so as to maintain a single-row state to form a spiral spring-like multi-row single-row multi-layer coil (single coil). Two of the obtained spiral spring-like multi-strip single-row multi-layer winding coil (single coil) are overlapped as shown in FIG. 1, and both ends of a plurality of insulated wires in the single coil are connected in parallel in the single coil. When two single coils are connected in series at the innermost periphery of the coil, both ends (lead wire portions) of the insulated wire constituting the coil are located at the outermost periphery of the coil, and the thickness in the axial direction of the coil Is a very thin and thin flat carp that fits into "two of the thin insulated wires" It is possible to obtain. That is, a thin flat coil having a large conductor cross-sectional area can be obtained with a thin conductor insulated wire.

  In this case, the number of insulated wires that are wound in an overlapping manner in order to produce the multi-row, single-row multilayer coil (single coil) is “the conductor diameter necessary to achieve the set allowable current value”. Should be greater than or equal to the value obtained by dividing the value obtained by dividing "the conductor diameter of the insulated wire" by this, so that "the conductor cross-sectional area of the coil composed of a plurality of insulated wires" is set. It will be able to handle the allowable current value sufficiently.

By the way, in order to wind an insulated wire in a single layer, the gap between the flanges (flanges) of the winding frame must be slightly larger than the outer diameter of the insulated wire, and the gap between the flanges is the same as the outer diameter of the insulated wire. If it exists, it cannot wind due to the frictional resistance between the flange surface and the insulated wire during winding. As described above, since the gap between the reels of the winding frame must be larger than the outer diameter of the insulated wire, the single-row multilayer winding coil that has been wound is actually displaced in the axial direction of the winding frame for each layer. As a result, the coil end face becomes uneven with every other insulated wire.
However, even with a single-row multilayer coil having an uneven end surface as described above, it is an unprecedented technique, but the uneven surface can be easily shaped by pressing the both sides of the coil so that it is a uniform flat surface. I found out that Moreover, even if the insulation wire is deformed so that it is slightly crushed by increasing the degree of pressing, the thickness of the insulated wire after deformation is secured at least π / 4 times (0.7854 times or more) the original outer diameter of the insulated wire. If this is done, the flatness of the coil end surface will not be adversely affected (if the degree of pressing exceeds the above value, the coil surface will be distorted and deformed), and the electrical and magnetic characteristics will deteriorate. Therefore, the axial thickness of the thin flat coil obtained by superposing two such coils can be further reduced.

The present invention has been completed based on the above knowledge and the like, and is characterized in that a flat coil having a small axial thickness is configured as follows.
1) Multiple insulated wire strands more than the square of the value obtained by dividing "conductor diameter necessary to achieve the set allowable current value" by "conductor diameter of insulated wire strands" are stacked in a row. A spiral spring-shaped multi-row, single-row, multi-layer wound coil is superposed, and a plurality of insulated wire elements constituting each of these coils are arranged in parallel within the coil and between the coils. A flat coil in which both ends of the coil wire are located on the outermost periphery of the coil, which are connected in series at the innermost periphery of the coil.
2) Each of the multi-row, single-row, multi-layer wound coils has a cross section that is pressed and deformed in the coil axial direction within a range not less than “π / 4” times the outer diameter of the insulated wire constituting the coil. The flat coil according to 1) above.
3) An electromagnetic energy converter using the flat coil described in 1) or 2) above.

  According to the present invention, both ends (lead wire portions) of the insulated wire constituting the coil are located on the outermost periphery of the coil and the axial thickness is necessary to achieve the set allowable current value. A multilayer wound flat coil that is thinner than twice the outer diameter of the insulated wire having a uniform conductor diameter (for two insulated wires that can pass the current required for the coil), This can greatly contribute to the compactness and high performance of cordless telephones and portable devices.

FIG. 1 is a schematic diagram for explaining a flat coil according to the present invention. FIG. 1 (a) shows an outline of the cross section, and FIG. 1 (b) shows an outline of observation from the plane direction. FIG. 2 is an explanatory diagram of a method of winding a plurality of insulated wire strands in a coil shape. FIG. 3 is an explanatory diagram of the non-contact charger described in the prior art. FIG. 4 is an explanatory view showing a state in which the winding start line portion of the multilayer winding coil is led out of the coil (outside of the outer periphery). FIG. 5 is an explanatory diagram of an aligned multilayer wound coil described in the prior art.

FIG. 1 is a schematic view for explaining an example of a flat coil according to the present invention. FIG. 1 (a) shows a cross section thereof, and FIG. 1 (b) shows an outline viewed from a plane direction. However, a flat coil is formed by overlapping two spiral spring-shaped single coils 1 produced by winding one row of insulated wires on a winding frame, and is formed in the inner diameter portion of the coil “a disc-shaped gap having no insulated wires. "2" is formed by connecting 3 winding start wire portions of both coils in series.
Here, in the flat coil according to the present invention, an insulated wire (insulated wire element wire) having an outer diameter smaller than that of “insulated wire having a conductor diameter necessary to achieve a set allowable current value” as an insulated wire. Are used, and a plurality of single-row multi-layer wound coils are wound at the same time, and then two multi-row single-row multilayer coils (single coils) are stacked. Here, as the insulated wire, a self-fused insulated wire is preferably used from the viewpoint of ease of manufacturing the coil.

  The number of insulated wire strands used is equal to or greater than the square of the value obtained by dividing the “conductor diameter necessary to achieve the set allowable current value” by the “conductor diameter of insulated wire strands”. Since the winding start line portion and the winding end line portion are respectively connected in parallel after winding, the conductor cross-sectional area of the coil can sufficiently correspond to the set allowable current value.

  By the way, the multi-row single-row multi-layer coil (single coil) is obtained by winding a large number of insulated wire strands in a single-layer multi-winding state, so that each wound insulated wire strand is located inside. As a result, the length of the wire is different from that of the wire that is located on the outside. Therefore, theoretically, each insulated wire that constitutes the coil also has a difference in electrical resistance, and the electrical and magnetic characteristics vary depending on the region. There is no doubt that it will not be a flat coil that maintains uniformity, but in practice this problem is not recognized. In addition, two multi-row single-row wound coils (single coils) as described above are stacked so that the winding directions are reversed, and the two single coils are connected in series at the innermost periphery of the coil. When the current flows through the two coils in the forward direction, there is no problem because a flat coil in which the difference in electric resistance due to the difference in the position of the insulated wire is leveled is realized.

  Incidentally, the flat coil according to the present invention is preferably manufactured by a method in which two single coils thus manufactured are overlapped and then connected to each winding start line. 2 (see FIG. 5), two multi-row, single-layer, multi-layer coils are overlapped, and the two coils have their winding start wire portions at the innermost circumference of the coil (axial surface portion of the winding frame). The two lead wire portions (winding end portions) of the coil may be a flat coil that is continuously connected at the outermost periphery of the coil.

As described above, in the flat coil according to the present invention, the lead wire portion of the insulated wire is located on the outermost periphery of the coil, and the axial thickness is necessary to achieve the set allowable current value. Although it is thinner than twice the outer diameter of an insulated wire having a conductor diameter (two insulated wires that can pass the current required for the coil), The following procedure can be taken.
a. For example, a plurality of self-bonding insulated wire elements whose number is equal to or greater than the square of the value obtained by dividing "the conductor diameter necessary to achieve the allowable current value required for instrument design" by "the conductor diameter of the insulated wire". To prepare,
b. The plurality of self-bonding insulated wires are stacked in multiple layers and wound using a coil winding frame so as to maintain a single-row state, thereby creating a spiral spring-shaped multi-row single-row multilayer coil (single coil). Make,
c. Two produced single coils are overlapped so that the winding direction is reversed, both ends of a plurality of insulated wire strands of the single coil are connected in parallel, and winding of the two single coils is started. By connecting the wire parts in series at the innermost circumference of the coil, a flat coil with two multi-row, one-row, multi-layer winding coils where both ends of the coil wire are located on the outermost circumference of the coil.

Incidentally, in the case of a coil where a 0.3 mmφ insulated wire is desired from the viewpoint of the allowable current value, for example, a 0.15 mmφ insulated wire is used as a bare wire, and four of them are stacked in a multilayer as shown in FIG. Winding flat multi-row single-row multilayer coil (single coil), and connecting both ends of these insulated wires in parallel, "cross-sectional area of 0.3mmφ insulated wire" and "0.15mmφ insulated wire" Since the total cross-sectional area of the combination is equivalent, even if it is a “coil using a combination of four 0.15 mmφ insulated wires”, the allowable current value is the same as “a coil using 0.3 mmφ insulated wires” It will be a thing.
Therefore, the flat coil made by stacking two “single coils using a combination of four 0.15 mmφ insulated wires” is thicker in the axial direction than the flat coil similarly made using 0.3 mmφ insulated wires. Is reduced to 1/2.

However, as described above, when an insulated wire is wound in a single row and multiple layers to produce a single row multilayer coil, in fact, it becomes an end surface with irregularities in every other layer of the insulated wire. Further, when the coil is taken out from the winding frame, the unevenness of the coil surface increases due to the winding pressure. This unevenness makes the thickness of the coil surface larger than the outer diameter of the insulated wire.
The following method is effective to solve this problem.

That is, the area of the circular cross section of the insulated wire having the outer diameter d is “π × (d / 2) ² ”, which can be expressed as “π × d × d / 4”, and the long side is d. Is equivalent to a rectangular area having a short side of π / 4 × d. Therefore, when pressing the end surface of a single-layer multilayer coil with unevenness from both sides, the uneven surface is first easily shaped into a uniform plane, but if the degree of pressing is further increased, the insulated wire will be crushed to some extent. Although deformed, if the thickness of the insulated wire in the pressing direction is at least “π / 4” times the outer diameter d of the original insulated wire (that is, “0.7854 × d” or more), the cross section is deformed into a rectangular shape. Therefore, there is no interference with the area of the dimension d occupied by the adjacent insulated wire, so that the coil is shaped while maintaining a flat shape, and the end face is fixed in a very flat multi-layer winding state. Become.
In addition, such a single-layer multilayer coil is not accompanied by deterioration of electrical and magnetic characteristics, and is advantageous in further reducing the axial thickness of the thin flat coil.

For example, using a winding frame with a reel diameter of 10 mm and a heel spacing of 0.18 mm, winding four self-fusing insulated wires with a conductor diameter of 0.15 mm and an outer diameter of 0.17 mm at the same time for 15 turns A multi-layer wound coil was produced, and the data of this coil was as follows.
Coil inner diameter: 10mm,
Coil outer diameter: 31mm,
Coil axial thickness (surface thickness): 0.19mm,
DC resistance: 0.24Ω.
The data of the end face shaped by pressing the end face of the coil from both sides was as follows.
Coil inner diameter: 10mm,
Coil outer diameter: 31mm,
Coil axial thickness (surface thickness): 0.15mm,
DC resistance: 0.24Ω.
In this way, two multi-row, single-row, multi-layer wound coils whose end surfaces are shaped are overlapped with each other in the winding direction, and the insulated wires in each coil are connected in parallel at the winding start end and winding end, respectively. A flat coil in which both ends of the coil are located on the outermost periphery was produced by connecting the winding start wire portions in series at the inner peripheral portion of the coil. The data of the flat coil was as follows.
Coil inner diameter: 10mm,
Coil outer diameter: 31mm,
Coil axial thickness: 0.30mm,
DC resistance: 0.48Ω.

  If the above-described flat coil according to the present invention is applied to an electromagnetic energy converter such as a cordless phone or a portable device (mobile phone, digital camera, portable game device), etc., its compactness is achieved. This is very advantageous for high performance and high performance.

  As described above, according to the present invention, a high-performance thin flat coil can be provided easily and inexpensively. For example, a non-contact charging system applied to portable electronic devices can be made compact and high-performance. Industrial applicability, such as being able to make a significant contribution to cost reduction and price reduction, cannot be realized.

DESCRIPTION OF SYMBOLS 1 Single row | line | column multilayer winding coil 2 The disk-shaped space | gap part in which an insulated wire does not exist 3 Connection part 4 The terminal (lead wire part) of an insulated wire
11, 15 Coil bobbin
12 Coil for power transmission
13 core
14, 17 housing
16 Power receiving coil
18 Multi-layer coil
19, 24 Winding start line
20, 25 End of line
21 Slit
22 Slideable frame
23 reel
26 Space
27 End of winding start line after multi-layer winding

Claims (3)

Multiple insulated wire strands more than the square of the value obtained by dividing the “conductor diameter necessary to achieve the set allowable current value” by the “conductor diameter of insulated wire strands” are stacked and wound in a row. Two spiral spring-shaped multi-row, single-row, multi-layer wound coils are superposed, and a plurality of insulated wires constituting each of the coils are arranged in parallel within the coils and between the coils. A flat coil in which both ends of a coil wire are located on the outermost periphery of the coil, characterized by being connected in series at the inner periphery. Each of the multi-row, single-row, multi-layer wound coil has a cross section that is pressed and deformed in the coil axial direction within a range not less than "π / 4" times the outer diameter of the insulated wire constituting the coil. The flat coil according to 1. An electromagnetic energy converter using the flat coil according to claim 1.

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