JP2013175621A - Magnetic sheet, transmission coil component and non-contact charging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic sheet and a transmission coil component which may contribute to improve power transmission efficiency of a non-contact charging apparatus and further, to improve efficiency of the non-contact charging apparatus by using such a transmission coil component.SOLUTION: A magnetic sheet is used while being disposed to face a power feeding device or a power receiving device of a non-contact charging apparatus. The magnetic sheet has an approximately rectangular outline and includes notched portions in four corners. A transmission coil component for the power feeding device or the power receiving device of the non-contact discharging apparatus is configured by disposing a planar coil and the magnetic sheet to face the planar coil.

Description

  The present invention relates to a magnetic sheet that functions as a magnetic shield, a magnetic yoke, or the like. Furthermore, it is related with the transmission coil components and non-contact charging device using the same.

  In recent years, small electronic devices and information communication devices have been improved in performance and functionality. In particular, mobile phones, web terminals, music players, etc. are used continuously for a long time for convenience as portable devices. Is required to be possible. In these small information communication devices, a secondary battery such as a lithium ion battery is used as a power source. This secondary battery charging method uses a contact charging method in which charging is performed by directly contacting the electrode on the power receiving side and the electrode on the power feeding side, and transmission coils are provided on both the power feeding side and the power receiving side, and electromagnetic induction is used. There is a non-contact charging method in which charging is performed by power transmission. Since the contactless charging method does not require an electrode for directly contacting the power feeding device and the power receiving device, it is possible to charge different power receiving devices using the same power feeding device.

  In the non-contact charging method, the magnetic flux generated in the primary transmission coil is fed by generating an electromotive force in the secondary transmission coil through the housing of the power feeding device and the power receiving device. Therefore, in order to obtain high power transmission efficiency in the non-contact charging method, it is necessary to match the central axes of the primary coil and the secondary coil.

  On the other hand, in order to obtain high power transmission efficiency, a coil yoke such as a magnetic sheet is installed on the opposite side of the transmission coil from the contact surface of the power feeding device and the power receiving device. The coil yoke has the following role. The first role is a role as a magnetic shield material. When leakage magnetic flux generated during the charging operation of the non-contact charging device flows to other components such as a metal member constituting the secondary battery, these components generate heat due to eddy current. The coil yoke can suppress this heat generation as a magnetic shield material. The second role of the coil yoke is to act as a yoke member for returning the magnetic flux generated in the coil during charging.

  For the purpose of providing a non-contact charging device with a simple structure while suppressing a decrease in power transmission efficiency, a configuration in which the magnetic attraction means is arranged inside the transmission coil and the central axes of the primary coil and the secondary coil coincide with each other. It is disclosed in Patent Document 1. In Patent Document 1, for example, a magnetic adsorption member is disposed concentrically in a central hole of a donut plate-shaped coil yoke, thereby suppressing magnetic saturation of the coil yoke and suppressing reduction in power transmission efficiency.

WO2011 / 096569

  According to the configuration described in Patent Document 1, it is possible to reliably position the power feeding device and the power receiving device while suppressing a decrease in power transmission efficiency while being a simple configuration. However, while there is a limit in improving the power transmission efficiency by the approach of suppressing the magnetic saturation of the coil yoke, Patent Document 1 discloses a specific means for reducing eddy current loss which is a main factor for the power transmission efficiency. Did not provide.

  In view of these points, an object of the present invention is to provide a magnetic sheet and a transmission coil component that can contribute to an improvement in power transmission efficiency of a non-contact charging device.

  The magnetic sheet of the present invention is a magnetic sheet that is used so as to face a coil in a power feeding device or a power receiving device of a non-contact charging device, and has an outer shape that is substantially rectangular, and has cutout portions at least at four corners. It is characterized by having. Such a configuration can contribute to suppression of eddy current loss and improvement of power transmission efficiency.

  Further, in the magnetic sheet, the notch is rectangular, and the shortest distance between the center of the magnetic sheet and the notch is smaller than the distance between the center and the closest side from the center. Is preferred. According to such a configuration, effects such as suppression of eddy current loss can be further enhanced.

  Further, the transmission coil component of the present invention is a transmission coil component for a power feeding device or a power receiving device of a non-contact charging device, which includes a planar coil and a magnetic sheet disposed so as to face the planar coil. The magnetic sheet according to the present invention is used as the magnetic sheet.

  Furthermore, in the transmission coil component, it is preferable that the magnetic sheet has an opening at a position on a winding axis of the planar coil. According to this configuration, the magnetic adsorption member can be disposed in the opening, and the transmission coil component for the power feeding device or the power receiving device of the non-contact charging device can be downsized.

  Furthermore, in the transmission coil component, it is preferable that the magnetic sheet has a portion surrounded by an annular opening at a position on a winding axis of the planar coil. According to such a configuration, the portion surrounded by the annular opening can be made to function as a magnetic attracting member disposed to face the permanent magnet. Moreover, since there is an annular opening, magnetic saturation of the magnetic sheet portion other than the portion is suppressed.

  The non-contact charging device of the present invention is a non-contact charging device having a power feeding device and a power receiving device that are used opposite to each other, wherein the power receiving device includes the transmission coil component.

  Furthermore, in the non-contact charging device, the power feeding device includes a planar coil for feeding, and the distance between the two opposite sides of the magnetic sheet is larger than the dimension of the planar coil for feeding, When the power feeding device and the power receiving device are opposed to each other, it is preferable that a part of the notch overlaps the planar coil for power feeding. According to such a configuration, it is possible to configure a non-contact charging device in which the magnetic sheet effectively functions as a magnetic shield and a magnetic yoke, and eddy current loss is also suppressed.

    According to the present invention, it is possible to provide a magnetic sheet, a transmission coil component, and a non-contact charging device that are suitable for improving power transmission efficiency.

It is a figure which shows the non-contact charging device provided with the electric power feeder and the receiving device. It is a figure which shows embodiment of the magnetic sheet which concerns on this invention. It is a figure which shows other embodiment of the magnetic sheet which concerns on this invention. It is a figure which shows other embodiment of the magnetic sheet which concerns on this invention. It is a figure which shows embodiment of the coil components which concern on this invention. It is a figure which shows other embodiment of the magnetic sheet which concerns on this invention.

    Hereinafter, embodiments of a magnetic sheet, a transmission coil component, and a non-contact charging device according to the present invention will be specifically described with reference to the drawings. However, the present invention is not limited thereto. Moreover, the structure demonstrated in each embodiment is applicable also in other embodiment, unless the meaning of other embodiment is impaired, In that case, the overlapping description is abbreviate | omitted suitably.

  FIG. 1 is a cross-sectional view showing a non-contact charging apparatus that performs power transmission between two transmission coil parts with two transmission coil parts facing each other. Each transmission coil component includes a planar coil and a magnetic sheet disposed to face the planar coil. One of the transmission coil components is a power receiving device, and the other is a power feeding device. A specific example of the non-contact charging device is, for example, a mobile communication terminal and its charger. The transmission coil component according to the present invention is applied to a power feeding device and / or a power receiving device. The power receiving device includes a battery unit alone in addition to an electronic device main body having a power receiving function such as a portable terminal.

  A power feeding device 12 connected to the AC power supply 10 includes a circuit unit 11. The circuit unit 11 includes a rectifier circuit that rectifies an alternating current and a switching circuit that converts the rectified direct current into a high-frequency current having a predetermined frequency. The power feeding device 12 includes a planar coil 7 and a magnetic attracting member 8 disposed inside the planar coil 7. The high-frequency current output from the circuit unit 11 flows through the planar coil 7 that is a primary transmission coil. The planar coil 7 is connected to a resonance capacitor (not shown) and resonates at the same frequency as the predetermined frequency converted by the switching circuit. The power feeding device 12 may be provided with a control circuit for controlling the operation of the switching circuit.

  The power receiving device 5 includes a planar coil 2 that is a secondary transmission coil, and a magnetic sheet 1 that is disposed on the rear surface side of the planar coil 2 as a coil yoke. The side facing the primary transmission coil is referred to as the front side, and the opposite side is referred to as the rear side. A resonance circuit can be configured by arranging a resonance capacitor in addition to the planar coil 2 as a secondary transmission coil. A secondary battery 4 is connected to the planar coil 2 via a rectifier circuit (not shown), and the induced current induced in the planar coil 2 by electromagnetic induction is rectified by the rectifier circuit. 4 is charged.

  The power feeding device 12 and the power receiving device 5 are accommodated in a nonmagnetic housing such as resin. Each of the casings has a flat surface, and charging is performed with the flat surfaces facing each other. The power feeding device and the power receiving device are positioned and fixed to each other using the magnetic adsorption member 8 described above. For example, the magnetic attracting member 8 is a magnet or a magnetic yoke that induces a magnetic flux from the magnet. A magnet can also be provided and positioned and fixed on the power receiving device side, but the magnetic sheet 1 has a function as a magnetic attracting member on the power receiving device side having the configuration shown in FIG. That is, the magnetic attracting member 8 on the power feeding device side and the magnetic sheet 1 on the power receiving device side are arranged to face each other, and the power feeding device 12 and the power receiving device 5 are positioned and fixed by the magnetic attracting force between them. Is done.

  The planar coils 2 and 7 are arranged inside the casing so that the winding axis thereof is perpendicular to the flat surface (the surface of the planar coil is parallel to the flat surface). On the opposite side (rear surface side) of the planar coils 2 and 7 to the flat surface, magnetic sheets 1 and 6 are respectively disposed adjacent to each other. For example, substrates 3 and 9 such as a resin substrate are disposed inside the housing. Note that the configurations of the magnetic sheet and the magnetic adsorption member can be interchanged between the power receiving device and the power feeding device. However, since there is a strong demand for downsizing the power receiving device, it is more preferable not to use a configuration including a magnetic attracting member separate from the magnetic sheet on the power receiving device side. The magnetic sheet 6 on the power feeding device side may be made of the same magnetic material as that of the magnetic sheet 1 on the power receiving side, but may be made of a different material. Further, the magnetic sheet 1 may be directly attached to the secondary battery 4 by omitting the power receiving side substrate 3. The magnetic sheets 1 and 6 are disposed so that the main surfaces thereof overlap or cover the planar coils 2 and 7 between the substrates 3 and 9 and the planar coils 2 and 7 on which the secondary battery 4 and the like are installed. Be placed. Accordingly, the magnetic flux generated by the planar coil 7 wound in a spiral shape converges and passes through the magnetic sheets 1 and 6, and the magnetic sheet functions as a magnetic yoke or a magnetic shield. The parts of the magnetic sheets 1 and 6 facing the winding axis direction of the planar coils 2 and 7 will be specifically described below.

(First embodiment)
In FIG. 2, the magnetic sheet used for the power receiving apparatus 5 of the above-mentioned non-contact charging device is shown as an example of the magnetic sheet according to the present invention. FIG. 2 is a plan view of a planar magnetic sheet as viewed from the normal direction of the main surface. The magnetic sheet 21 shown in FIG. 2 has a substantially rectangular outer shape, and has notches 22 at four corners. The rectangle includes a rectangle and a square, and the approximate rectangle means that it can be recognized as a square or a rectangle as a whole, excluding partial unevenness such as a notch. In FIG. 2, the magnetic sheet portions at the four corners before the notch 22 is provided are indicated by dotted lines. In the embodiment shown in FIG. 2, each notch is a square, and the notch is provided. The outer shape of the magnetic sheet in the absence is square. The reason for providing the notch is as follows. For example, when power is supplied by a circular planar coil, the magnetic flux flowing in the magnetic sheet used in a facing manner is the radial direction, and the direction of the eddy current generated by the change of the magnetic flux is the circumferential direction. Therefore, by providing the cutouts at the four corners of the rectangular magnetic sheet, the flow of eddy current can be divided, and eddy current loss can be reduced and transmission efficiency can be improved. The shape of the notch is not limited to a square, and may be, for example, a rectangle, or a wedge shape whose tip is directed to the center of the magnetic sheet (a configuration in which the corner of the notch on the magnetic sheet center side is an acute angle). However, from the viewpoint of ease of forming the notch, that is, from the viewpoint of cost, the notch is preferably rectangular. Further, in addition to the cutout portions at the four corners, cutout portions may be provided at portions other than the four corners.

  Although the effect of reducing the eddy current loss can be expected by providing the notch as described above, regarding the size of the notch, the shortest distance d1 between the center C of the magnetic sheet 21 and the notch 22 is: It is more preferable to form the magnetic sheet so as to be smaller than the distance d2 between the center C of the magnetic sheet and the nearest side. This is because the effect of dividing the flow path of the eddy current is enhanced. Since the magnetic sheet 21 shown in FIG. 2 has a square shape, the closest side from the center is four sides, but in the case of a rectangle, a set of long sides is the closest side. The upper limit of the size of the notch is not particularly limited from the viewpoint of dividing the flow path of the eddy current, but if the notch becomes too large, the magnetic function that functions as a magnetic yoke or shield is not limited. The body part is reduced. If the cutout portion is rectangular, the total length of the cutout portions on each side of the magnetic sheet is 2/3 or less of the length of each side when there is no cutout portion. Good. Moreover, in order to raise the effectiveness of a notch part, it is good to set it as 1/10 or more.

(Second Embodiment)
FIG. 3 shows another embodiment of the magnetic sheet according to the present invention. FIG. 3 is a plan view of a planar magnetic sheet as viewed from the normal direction of the main surface. The magnetic sheet 31 shown in FIG. 3 has a substantially rectangular outer shape and has a circular opening 33. Portions other than the opening 33 such as the notch 32 are the same as those in the embodiment shown in FIG. In the embodiment shown in FIG. 3, the opening 33 is provided in the center of the magnetic sheet 31, but is not limited to this. When the transmission coil component is configured so as to face the planar coil, the opening 33 may be provided so as to be disposed at a position on the winding axis of the planar coil. The power feeding device and the power receiving device are arranged so that the winding axes of the coils included therein are coincident. Therefore, when a magnetic attracting member is provided on the central axis of the coil of the power supply device, an attracting member on the power receiving device side is disposed in the opening by providing an opening in a corresponding portion of the magnetic sheet of the power receiving device. The power receiving device can be downsized. In this case, the magnetic sheet is also prevented from being magnetically saturated by the magnetic attracting member on the power feeding device side. The shape of the opening 33 can be an ellipse, a square, a rectangle, or the like in addition to a circle. However, the shape of the opening is preferably similar to the shape of the end face of the magnetic attracting member to be placed or the inner shape of the planar coil disposed around the magnetic attracting member, and more preferably circular. Note that the similarity in this case means that, in the case of a rectangle, the overall shape may be a similar shape regardless of the difference in the rounded corners or minute irregularities.

(Third embodiment)
FIG. 4 shows another embodiment of the magnetic sheet according to the present invention. FIG. 4 is a plan view of a planar magnetic sheet as viewed from the normal direction of the main surface. The magnetic sheet 41 shown in FIG. 4 has a substantially rectangular outer shape and is the same as the embodiment shown in FIG. The embodiment shown in FIG. 4 has an opening, but the form is different from the embodiment shown in FIG. In the embodiment shown in FIG. 3, the entire portion surrounded by a circle is open, whereas in the embodiment shown in FIG. 4, the magnetic sheet 41 has a portion 44 surrounded by an annular opening 43. . Hereinafter, the portion 44 surrounded by the annular opening 43 is also referred to as a second magnetic sheet portion 44, and the other portion is also referred to as a first magnetic sheet portion. The second magnetic sheet portion is arranged apart from the edge of the opening 43 except for a part thereof, and is circular as a whole except for the part, and is similar to the inner shape of the opening 43. The “part” here is a portion in which a connecting portion 45 described later is formed.

  When the magnetic sheet is arranged on the rear surface side of the planar coil to constitute a transmission coil component such as a power receiving device for a non-contact charging device, the first magnetic sheet portion mainly functions as a coil yoke or a magnetic shield. . Therefore, when configuring the non-contact charging device, the outer edge of the first magnetic sheet portion is more than the outer edge of the feeding-side planar coil so that the first magnetic sheet portion covers the planar coil on the feeding side. It is preferable to make the shape and arrangement so as to be outside.

  When the transmission coil component is configured using the magnetic sheet and the planar coil, the second magnetic sheet portion is disposed so as to be positioned on the winding axis of the planar coil. The power feeding device and the power receiving device are arranged so that the winding axes of the coils included therein are coincident. Therefore, when a magnetic attraction member is provided on the central axis of the coil of the power feeding device, the portion 44 (second magnetic sheet portion 44) surrounded by the annular opening 43 is disposed opposite to the permanent magnet. Can function as. Even in such a case, since the second magnetic sheet portion 44 is disposed away from the edge of the opening 43, the flow of magnetic flux from the second magnetic sheet portion 44 to the first magnetic sheet portion and the The magnetic saturation of the first magnetic sheet portion due to can be suppressed. Although it is possible to make the inner shape of the opening 43 different from the outer shape of the second magnetic sheet portion 44, in the embodiment shown in FIG. 4, in order to prevent the magnetic flux from concentrating on a specific portion, The outer shape of the inner shape and the second magnetic sheet portion 44 are both circular, and the distance between the edge of the opening 43 and the outer edge of the second magnetic sheet portion 44 facing the edge is the second magnetic sheet portion 44. It is made constant along the outer edge. The distance between the edge of the opening 43 and the outer edge of the second magnetic sheet portion facing the edge is set to, for example, 1 mm or more when a magnetic sheet is formed using a ribbon such as a microcrystalline soft magnetic alloy ribbon. Good. The interval is more preferably 1.5 mm or more. On the other hand, if the interval becomes too large, the leakage magnetic flux toward the rear surface side increases. In order to reduce the leakage magnetic flux, it is preferable to set it to 4 mm or less. The interval is more preferably 3 mm or less.

  In the magnetic sheet shown in FIG. 4, the first magnetic sheet portion and the second magnetic sheet portion are integrally formed, and a part of the second magnetic sheet portion 44 and a part of the first magnetic sheet portion are formed. A connecting portion 45 to be connected is provided. As a magnetic sheet having a portion surrounded by an annular opening at a position on the winding axis of the planar coil, the second magnetic sheet portion 44 and the first sheet portion are provided without providing the connecting portion 45. A completely spaced configuration may be used. Even with such a configuration, the above-described function as a magnetic attracting member disposed to face the permanent magnet and the effect of suppressing the magnetic saturation of the first magnetic sheet portion can be obtained. In the embodiment shown in FIG. 4, since the first magnetic sheet portion and the second magnetic sheet portion are integrally formed, the first magnetic sheet portion and the second magnetic sheet portion are made of the same material, Except for the shape, they have substantially the same properties. In this case, the thickness of the first magnetic sheet portion and the second sheet portion is substantially the same. A typical example of such a configuration is a quenched ribbon. The presence of the connecting portion 45 makes it possible to integrally form a plurality of magnetic sheet portions having different functions as described above. For example, since the magnetic adsorption member disposed opposite to the permanent magnet can be constituted by the second magnetic sheet portion 44 formed integrally with the first magnetic sheet portion, the number of parts can be reduced, and the magnetic adsorption member has a low profile. Through this, it is possible to reduce the size of the non-contact charging device and the transmission coil parts used therefor, simplify the configuration, and simplify the manufacturing / use process.

  Here, the connecting part 45 connects a part of the second magnetic sheet part and a part of the first magnetic sheet part, and the second magnetic sheet part 44 is shaped like a cantilever. It is connected to the magnetic sheet part. It is necessary that at least the width of the connecting portion 45 is smaller than the width of the second magnetic sheet portion 44 in the same direction and that the outer shape of the second magnetic sheet portion 44 can be recognized as a circle, a rectangle, or the like. If these configurations are satisfied, it is possible to divide and form the connecting portion. However, from the viewpoint of securing the function of the opening and simplifying the process, the connecting portion is preferably configured in one place. . From the viewpoint of suppressing the flow of magnetic flux from the second magnetic sheet portion 44 to the first magnetic sheet portion, the width of the connecting portion 45 is 0.2 or less in comparison with the entire outer periphery of the second magnetic sheet portion 44. Preferably, 0.1 or less is more preferable. On the other hand, if the width of the connecting portion is too small, the strength is lowered, so that the ratio is preferably secured to 0.01 or more. In the case of a non-contact charging apparatus, the upper limit of the absolute value of the width of the connecting portion 45 is, for example, 6 mm or less, more preferably 5 mm. The lower limit is preferably 1 mm or more.

  The magnetic sheet shown in FIG. 4 is suitably used for a non-contact charging apparatus as shown in FIG. In this case, as shown in FIG. 1, when viewed from the facing direction of the magnetic attracting member 8 and the second magnetic sheet portion, the facing surface of the second magnetic sheet portion 44 is closer to the facing surface of the magnetic attracting member 8. More preferably, the second magnetic sheet portion is configured to include the entire magnetic adsorption member 8 inside. According to this structure, it can suppress more effectively that the magnetic flux from the magnetic adsorption member 8 flows into the 1st magnetic sheet part. In addition, by allowing the opposing surface of the second magnetic sheet portion 44 to be larger than the opposing surface of the magnetic attracting member 8, an allowable amount of positional deviation between the power receiving device and the power feeding device is also increased. It is more preferable that the second magnetic sheet portion 44 has a size relationship and arrangement such that the outer edge of the second magnetic sheet portion 44 is 1 mm or more outside the outer edge of the magnetic attracting member when viewed from the facing direction.

  Further, the magnetic sheet shown in FIG. 4 has a communication portion 46 that allows the opening 43 to communicate with the outer edge side of the first magnetic sheet portion. In the configuration shown in FIG. 4, the communication portion 46 is arranged such that its longitudinal direction is directed toward the center of the opening 43. Since the communication portion 46 is formed, the opening 43 becomes an open opening that continues to the outer edge of the first magnetic sheet portion. For example, when a magnetic sheet is taken out from a magnetic metal ribbon, when the opening 43 is formed, the ribbon corresponding to the opening 43 needs to be removed. If the opening 43 is a closed opening, it is difficult to remove the strip at such a portion. On the other hand, if the opening is open with respect to the outer edge of the magnetic sheet portion, the portion corresponding to the opening 43 connected to the outer portion is thin when removing the outer portion of the magnetic sheet portion. The band can be removed at the same time, and the process can be simplified.

  Although the position of the communication part 46 should just be a position which does not interfere with the connection part 45, it is more preferable that the communication part 46 is arrange | positioned on the opposite side of the connection part 45 on both sides of the 2nd magnetic sheet part 44. FIG. For example, when the base material is peeled in one direction to take out the magnetic sheet from the base material, the base material corresponding to the opening cannot be removed smoothly if the communication portion and the connection portion are too close. On the other hand, the communication part 46 is arranged on the opposite side of the connecting part 45 with the second magnetic sheet part 44 interposed therebetween, so that the removal is facilitated. In the configuration shown in FIG. 4, the arrangement is such that the communication direction of the communication portion 46 and the connection direction of the connection portion 45 are on the same straight line, that is, the angle viewed from the center of the second magnetic sheet portion is 180 degrees. It is arranged like this.

  The transmission coil component and the non-contact charging device configured using the magnetic sheet according to the present invention will be further described. As shown in FIG. 1, the non-contact charging device includes a power feeding device and a power receiving device that are used in a mutually opposed manner. An example in which a transmission coil component is configured using the magnetic sheet shown in FIG. 4 and the transmission coil component is applied to a power receiving device will be described below.

  FIG. 5 shows the arrangement of the magnetic sheets 51 and 54 on the power receiving device side and the planar coil for power feeding provided in the power feeding device in the facing direction (the main surface of the magnetic sheet and the normal direction of the main surface of the planar coil). It is the figure seen from. In the figure, the power feeding coil of the power feeding device is represented by a dotted line, and the smaller circle is the inner shape of the coil and the larger circle is the outer shape of the coil. In the embodiment of FIG. 5, the inner shape of the feeding coil is formed smaller than the annular opening and the portion surrounded by the opening, but the inner shape of the feeding coil is the annular opening and You may form with the same magnitude | size as the part enclosed by this opening part or more. The power feeding device includes a magnet for attracting the power receiving device on a winding axis of a planar coil for power feeding. By arranging the magnet so as to fit inside the power supply coil, the contactless charging device can be reduced in size. 5A and 5B show a configuration in which the distance between the two opposite sides of each of the magnetic sheets 51 and 54 of the power receiving device is larger than the size of the planar coil 53 for power feeding of the power feeding device. ing. With this configuration, the function as a coil yoke for inducing magnetic flux generated by the power feeding coil and the function as a magnetic shield are enhanced. In FIG. 5A, with the emphasis on such a function, the rectangular cutout 52 is formed in a size that does not overlap the power supply coil 53. On the other hand, in FIG. 5B, when the rectangular notch 55 is made larger than the notch 52 in FIG. 5A and the power feeding device and the power receiving device are opposed to each other, a part of the notch 55 is formed. It is configured to overlap with the planar coil 53 for power feeding. With this configuration, the cutout portion 55 acts so as to divide the flow path of the eddy current generated by the change in the magnetic flux generated by the power supply coil 53, and the eddy current loss can be reduced and the transmission efficiency can be improved. In the configuration of FIG. 5B, the shortest distance between the center of the magnetic sheet 54 and the notch 55 is also made smaller than the distance between the center of the magnetic sheet and the closest side.

  As the soft magnetic material used for the magnetic sheet, ferrite, a silicon steel plate, a magnetic ribbon manufactured by roll quenching (hereinafter, also simply referred to as a ribbon), and a composite material of these and a resin can be used. In order to reduce eddy current loss and improve charge transmission efficiency, it is preferable to make the soft magnetic material thinner. In this respect, a magnetic alloy ribbon manufactured by roll quenching or the like is preferable. Specifically, a thin film having a thickness of 50 μm or less made of an Fe-based amorphous ribbon, a Co-based amorphous ribbon, an Fe-based nanocrystalline soft magnetic alloy ribbon, a Co-based nanocrystalline soft magnetic alloy ribbon having a high saturation magnetic flux density, or the like. Use a belt. Among these, since the microcrystalline soft magnetic alloy ribbon such as the Fe-based nanocrystalline soft magnetic alloy ribbon has a high magnetic permeability, the first magnetic sheet portion and the second magnetic sheet portion that are integrally formed. It is particularly preferable that the connecting portion is made of such a microcrystalline soft magnetic alloy ribbon. On the other hand, high permeability materials are generally easily magnetically saturated. The magnetic sheet according to the present invention employs a configuration in which the first magnetic sheet portion and the second magnetic sheet portion are separated from each other, and the magnetic yoke is not easily saturated as a coil yoke. It is particularly effective to configure using The thickness of one thin ribbon is more preferably 30 μm or less, and further preferably 25 μm or less. When a magnetic ribbon manufactured by roll quenching is used, the magnetic sheet may be composed of a single ribbon layer, or the magnetic sheet is composed of a laminate in which a plurality of ribbons are laminated via a resin or the like. May be. By configuring the magnetic sheet with a laminate, magnetic saturation is less likely to occur.

  The magnetic sheet constituted by lamination or the like is preferably fixed to the reinforcing member in order to prevent breakage. Specifically, it is preferable to use a magnetic sheet obtained by laminating a metal ribbon with a resin sheet or the like. A resin sheet may be provided on one of the two main surfaces of the front and back, or may be provided on both. However, it is more preferable to provide resin sheets on both the front and back two main surfaces from the viewpoint of ensuring strength and preventing scattering of fragments at the time of breakage. By using a resin sheet, excellent flexibility can be imparted to the magnetic sheet. In addition, since the notch part is the meaning formed in the magnetic body part as mentioned above, the part of the said resin sheet does not necessarily need to be a notch. However, by forming the cutout portion including the resin sheet portion, the space of the cutout portion can be used for other members. When the magnetic sheet is composed of a soft magnetic alloy ribbon, it may be composed of, for example, about 2 to 30 layers. However, from the viewpoint of cost reduction, the number of thin ribbons is more preferably 10 or less. The total thickness of all soft magnetic materials used in the magnetic sheet can be 500 μm or less. In order to reduce the height, the thickness is preferably 300 μm or less.

Example 1
The transmission coil component was configured using a magnetic sheet having a square notch shown in FIG. A microcrystalline soft magnetic alloy ribbon was used as the soft magnetic material of the magnetic sheet. As a microcrystalline soft magnetic alloy ribbon, Finemet (registered trademark) (FT3M material, thickness 18 μm) manufactured by Hitachi Metals, Ltd. was used. Six sheets of this thin ribbon with a double-sided adhesive sheet (thickness: 10 μm) were laminated, and a PET resin with a thickness of 31 μm was adhered to the thin strip exposed on the uppermost surface. The total thickness of this laminated magnetic sheet was 199 μm, of which the total thickness of the magnetic part was 108 μm. The outer shape of the first magnetic sheet portion is square, and the length and width are 45 mm. A plurality of laminated magnetic sheets having different notch sizes were prepared. For comparison, a magnetic sheet without a notch was also prepared. A transmission coil component on the power receiving side (secondary side) was configured by combining the laminated magnetic sheet and the planar coil. The planar coil was constructed by winding two parallel wires with a wire diameter of 0.32 mm for 15 turns, and the outer shape of the coil was a 40 × 20 mm rectangle, and the inner shape was a 20 mm × 10 mm rectangle. On the other hand, a planar coil on the power supply side (primary side) is formed by winding a litz wire with a wire diameter of 1 mm for 20 turns (10 turns, 2 stages), the outer shape of the coil is a circle with a diameter of 40 mm, and the inner shape is a diameter of 20 mm. The round shape. Ferrite was used for the primary side magnetic sheet. The transmission coil part is configured by aligning the center of the magnetic sheet and the planar coil, and the transmission coil part on the power feeding side and the transmission coil part on the power receiving side are arranged in the same manner as in FIG. 1, and the inductance Ls and Q value are measured at 120 kHz. did. The results are shown in Table 1. In addition, in the table | surface, the overlap of a notch part and a coil for electric power feeding was represented by the difference of the radius of the external shape of a coil for electric power feeding, and the shortest distance d1 of the center of a magnetic sheet, and a notch part.

  No. provided with a notch. The structure of No. 2 etc. is No. which is not provided with a notch. It can be seen that the Q value is improved compared to the configuration of 1. In addition, the shortest distance d1 between the center of the magnetic sheet and the notch is smaller than the distance d2 between the center of the magnetic sheet and the closest side. It can be seen that in the configuration of 3 etc., Q is further improved. In addition, a part of the notch overlaps with the planar coil for power feeding. In the configurations of 4 to 6, it can be seen that the rate of improvement of Q is further increased. In addition, when the notch portion is made large so as not to overlap the notch portion and the planar coil for power feeding (No. 2 and No. 3), the improvement amount of Q is slightly reduced, but the Ls is reduced. It can also be seen that it can be suppressed.

(Example 2)
The transmission coil component was configured using a magnetic sheet having a wedge-shaped notch shown in FIG. In addition, in the magnetic sheet shown in FIG. 6, notch portions were provided between the four corners in addition to the four corners. A magnetic sheet and a transmission coil component were constructed and evaluated in the same manner as in Example 1 except that the shape of the notch was different and that seven layers of microcrystalline soft magnetic alloy ribbon were used. For comparison, a magnetic sheet provided with only an opening and a communication portion without a wedge-shaped notch was prepared and evaluated. The results are shown in Table 2.

  No. with wedge-shaped notches The configuration of No. 8 is provided with no cutouts. Compared to the configuration of 7, the Q value was improved. That is, it can be seen that even when a wedge-shaped notch other than a rectangle is provided, an improvement in the Q value can be realized while suppressing a decrease in Ls.

(Example 3)
A transmission coil component was constructed and evaluated in the same manner as in Example 1 using a magnetic sheet having a square notch shown in FIG. In addition to a magnetic sheet having a notch size of 5 mm × 5 mm and a magnetic sheet having a size of 7.5 mm × 7.5 mm, a magnetic sheet without a notch was prepared for comparison. The size (diameter) of the inner shape of the opening of the magnetic sheet was 25 mm, the diameter of the portion surrounded by the annular opening (second magnetic sheet) was 20 mm, and the width of the communicating portion was 4 mm. The evaluation results are shown in Table 3.

  No. provided with a notch. The structure of No. 10 in which the notch portion is not provided. Compared to the configuration of 9, the Q value was improved. Furthermore, no. The structure of No. 10 which has the same notch part and is not provided with the opening part and the second magnetic sheet part. It can be seen that both the inductance and the Q value are superior to those of the third configuration. No. 2 having the second magnetic sheet portion. In the configuration of 10, the positioning and fixing of the transmission coil parts were also good.

DESCRIPTION OF SYMBOLS 1, 6: Magnetic sheet 2, 7: Planar coil 3, 9: Board | substrate 4: Secondary battery 5: Power receiving apparatus 8: Magnetic adsorption member 10: AC power supply 11: Circuit part 12: Power feeding apparatus 21, 31, 41, 51, 61: Magnetic sheets 22, 32, 42, 52, 62: Notches 33, 43, 63: Opening 44: Portion surrounded by annular opening 43 (second magnetic sheet)
45: Connection part 46: Communication part 53: Planar coil

Claims (7)

In a power feeding device or a power receiving device of a non-contact charging device, a magnetic sheet used by being arranged so as to face a coil,
A magnetic sheet having a substantially rectangular outer shape and having notches at at least four corners.   The notch is rectangular, and the shortest distance between the center of the magnetic sheet and the notch is smaller than the distance between the center of the magnetic sheet and the closest side. The magnetic sheet as described. A transmission coil component for a power supply device or a power reception device of a non-contact charging device, comprising a planar coil and a magnetic sheet disposed to face the planar coil,
A transmission coil component, wherein the magnetic sheet is the magnetic sheet according to claim 1.   The transmission coil component according to claim 3, wherein the magnetic sheet has an opening at a position on a winding axis of the planar coil.   The transmission coil component according to claim 3, wherein the magnetic sheet has a portion surrounded by an annular opening at a position on a winding axis of the planar coil. A non-contact charging device having a power feeding device and a power receiving device that are used facing each other,
The said power receiving apparatus is provided with the transmission coil components as described in any one of Claims 3-5, The non-contact charging device characterized by the above-mentioned. The power feeding device includes a planar coil for power feeding, and the distance between two pairs of opposite sides of the magnetic sheet is larger than the dimension of the planar coil for power feeding,
The contactless charging apparatus according to claim 6, wherein when the power feeding device and the power receiving device are opposed to each other, a part of the notch overlaps the planar coil for power feeding.

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