JP2016127700A - Power reception device, and capsule for mounting the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power reception device, having high power reception efficiency enabling mounting on a capsule, and a capsule for mounting the power reception device.SOLUTION: A power reception device 10 for acquiring power from a power transmission device, which performs non-contact power transmission, includes: a body 20 formed of a material having high magnetic permeability; a capacitor module 13 disposed in the body; and a power reception coil 12 disposed to be wound around a side face of the body; and electrically connected to the capacitor module. The capacitor module includes: a module including a resonance capacitor, which constitutes a resonant circuit with the power reception coil, and a rectifier circuit; and a power storage capacitor for storing power.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power receiving device, and more particularly to a power receiving device for non-contact power transmission using magnetic field resonance.

  As a technique for transmitting electric power in a non-contact manner, a method using a magnetic resonance phenomenon having a longer transmission distance than a method using an electromagnetic induction phenomenon has been actively developed. A basic power transmission / reception system using a magnetic field resonance phenomenon includes a pair of resonance coils (for example, an LC resonance coil) of a power transmission coil and a power reception coil arranged to face each other. A resonance circuit is constituted by the coil and the capacitor. In the magnetic field resonance method, resonance occurs between the coils with respect to the resonance frequency, and power is transmitted from the power transmission apparatus to the power reception apparatus through a high-frequency magnetic field. A large coil is used when the transmission distance is long, and a large coil is also used when the transmission power is large.

  Non-contact power transmission is also being studied for implantable capsules and capsule endoscopes. Since it is mounted on a capsule with a limited size, a power receiving device applied to such a use is required to be downsized. The received power is stored in the storage capacitor and supplied to various functional elements.

  A capsule endoscope to which non-contact power transmission is applied is disclosed (for example, Non-Patent Document 1). The capsule endoscope disclosed here is a general configuration of a micro capsule CCD camera having a pill-shaped outer shape having a diameter of 9 mm and a length of 23 mm. The power receiving coil, the storage capacitor, and the resonant capacitor are mounted on the capsule together with other components.

  On the other hand, non-contact power transmission of a magnetic mechanical system using a mechanical resonator has been proposed (for example, Patent Document 1). In this, the mechanical resonator is placed in the space inside the coil and mechanical energy is reconverted into electrical energy using the dynamo principle. By using a mechanical resonator, an extremely high Q value is realized as seen in a crystal resonator or FBAR (Film Bulk Acoustic Resonator). The Q value is a value representing the sharpness of the resonance frequency characteristic peak. The larger the Q value, the lower the energy consumption and the longer the vibration, which is desirable.

JP 2014-18066 A

R.F., Inc., Capsule Endoscope NORIKA, [online], [searched on November 6, 2014], Internet <URL: http://rfsystemlab.com/sayaka/norika/system/001.html>

  When the power receiving device for non-contact power transmission is downsized, it is difficult to increase power receiving efficiency. In the configuration as shown in Non-Patent Document 1, there are only two methods for increasing the power receiving efficiency. One is to increase the receiving aperture of the coil as much as possible, and the other is to increase the Q value of the coil. However, any method is limited and the purpose cannot be sufficiently achieved.

  If a large chip coil is used, the receiving opening of the coil can be enlarged, but the arrangement and use of metal parts are restricted so that the magnetic lines reaching the large chip coil are not shielded. Considering restrictions on metal parts, a large chip coil cannot be used, and a chip coil as small as possible must be used. Further, the capacitor for constituting the resonance circuit includes a metal electrode, and the storage capacitor includes a metal component such as a current collector made of metal or an envelope. When magnetic lines of force are applied to the surfaces of these metal electrodes and metal parts, an induced current flows and the lines of magnetic force are canceled out. This prevents magnetic field lines from reaching the coil. Furthermore, the phenomenon that the magnetic force is changed to heat also occurs, and the power receiving efficiency may be greatly reduced. Among the power receiving devices for non-contact power transmission, in particular, since the capsule endoscope moves in the human body and changes its direction, it is difficult to uniquely determine the arrangement of metal parts that can avoid the above-described problems. .

  In general, since an electrically configured resonance circuit (LC circuit or the like) cannot avoid a resistance loss, it is difficult to realize a high Q value in such a resonance circuit.

  In the technique of Patent Document 1, the mechanical resonator needs to be arranged in the coil, and the structure is limited. Thus, in the structure in which the mechanical resonator is arranged in the coil, the coupling with the external magnetic field is insufficient.

  In view of the above, an object of the present invention is to provide a power receiving device that can obtain a high power receiving efficiency and can be mounted on a capsule, and a power receiving device mounted capsule.

  A power receiving device according to the present invention is a power receiving device that acquires power from a power transmitting device that transmits contactless power, a main body formed of a material having high magnetic permeability, a capacitor module provided in the main body, A power receiving coil that is wound around a side surface of the main body and electrically connected to the capacitor module, and the capacitor module includes a resonant capacitor and a rectifier circuit that form a resonant circuit together with the power receiving coil; And a storage capacitor for storing electric power.

  A power receiving device mounting capsule according to the present invention is characterized in that the power receiving device described above is mounted in a capsule-type casing.

  According to the present invention, the power receiving device includes a main body made of a material having high magnetic permeability, and a capacitor module is provided in the main body. Thereby, since the capacitor module is magnetically shielded, even if the capacitor module includes a metal part, the magnetic field lines are not affected by the metal part. Power generation efficiency can be increased by suppressing the generation of induced current due to the metal parts. At the same time, the lines of magnetic force are collected in a material having a high magnetic permeability, so that the lines of magnetic force passing through the power receiving coil are increased, and the power receiving efficiency can be increased.

  On the other hand, since the power receiving coil is wound around the side surface of the main body provided with the capacitor module therein, the opening diameter of the power receiving coil is a size corresponding to the diameter of the core included in the main body. .

  By selecting the diameter of the core, the opening diameter of the power receiving coil can be easily matched to the capsule diameter in which the power receiving device is mounted. Moreover, since the components other than the power receiving coil are provided in the main body as a capacitor module, the power receiving device can be reduced in size and can be used for mounting a capsule.

  As described above, the power receiving coil is wound around the side surface of the main body, and components other than the power receiving coil are provided inside the main body. Therefore, there is no component that shields the lines of magnetic force reaching the power receiving coil. A capsule equipped with such a power receiving device can receive power with high efficiency even when it moves in the human body and changes its direction with respect to the lines of magnetic force.

It is the schematic which shows the electrical schematic structure of the non-contact electric power transmission system using the power receiving apparatus which concerns on 1st Embodiment. It is a perspective view which shows the power receiving apparatus which concerns on 1st Embodiment. It is a perspective view of the power receiving device mounting capsule according to the first embodiment. 1 is a side view of a power receiving device according to a first embodiment. It is a disassembled perspective view of the power receiving apparatus which concerns on 1st Embodiment. It is the figure seen from the module side of a capacitor module. It is the figure seen from the electrical storage capacitor side of a capacitor module. It is a disassembled perspective view of the capacitor module in a manufacturing process. It is a figure explaining 1 process of the manufacturing method of the power receiving apparatus of 1st Embodiment. It is a figure explaining the process following FIG. It is a disassembled perspective view of the power receiving apparatus which concerns on 2nd Embodiment. It is a figure explaining the equivalent circuit containing a mechanical resonator and a receiving coil. FIG. 13A is a diagram illustrating an electrical equivalent circuit including a mechanical resonator and a power receiving coil. FIG. 13A illustrates an equivalent circuit of the mechanical resonator including an electrical converter, and FIG. 13B illustrates an equivalent circuit at the time of resonance. Represent. It is a figure explaining the equivalent circuit containing load. It is a figure explaining an equivalent circuit when a matching circuit is attached. It is a perspective view which shows the modification (1) of the upper cover in the power receiving apparatus which concerns on 2nd Embodiment. It is C-C 'sectional drawing of the upper cover shown in FIG. It is a perspective view which shows the modification (2) of the upper cover in the power receiving apparatus which concerns on 2nd Embodiment. It is D-D 'sectional drawing of the upper cover shown in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
A non-contact power transmission system 8 illustrated in FIG. 1 includes a power transmission device 6 and a power reception device 10, and transmits power from the power transmission device 6 to the power reception device 10 in a contactless manner. In FIG. 1, the power transmission device 6 includes a high-frequency power source 2 and a power transmission coil 4.

  The power receiving device 10 includes a power receiving coil 12, a chip component group 14 including a resonance capacitor 14a and a rectifier circuit 14b, and a storage capacitor 13b. Although not shown, the chip component group 14 may include a resistor or the like. A resonance circuit (matching circuit) can be configured by the resonance capacitor 14 a and the power receiving coil 12.

  The power receiving coil 12 in the power receiving device 10 can be magnetically coupled to the power transmitting coil 4 in the power transmitting device 6 and acquires power from the power transmitting coil 4 based on the magnetic field resonance phenomenon. The high frequency generated by the magnetic field resonance phenomenon is converted into direct current by the rectifier circuit 14b and used as electric power. The electric power is stored in the storage capacitor 13 b and supplied to the load 20.

  The capacitors such as the resonance capacitor 14a and the storage capacitor 13b include a metal envelope. Moreover, the current collector contained in such a capacitor is made of metal. If a metal part such as an envelope or a current collector is present in the magnetic field, an induced current is generated to cancel the magnetic lines of force, thereby reducing the power receiving efficiency of the power receiving device 10.

  The power receiving device 10 of the first embodiment is intended to improve the power receiving efficiency by reducing the influence of the induced current caused by the metal portion of the capacitor and increasing the opening diameter of the power receiving coil.

1. Configuration As shown in FIG. 2, the power receiving device 10 includes a main body 20. A capacitor module 13 is provided inside the main body 20, and the power receiving coil 12 electrically connected to the capacitor module 13 is wound around the side surface of the main body 20.

  The main body 20 includes a disk-shaped core 11 having a predetermined thickness, and a lower lid 17 and an upper lid 18 disposed on the lower surface and the upper surface of the core 11. Specifically, the power reception coil 12 is wound around the side surface of the disk-shaped core 11. As will be described later, the capacitor module 13 is accommodated in an accommodating portion provided in the core 11. For this reason, the core 11 has a diameter and thickness that can accommodate at least the capacitor module 13. Since the power receiving device 10 of the first embodiment is required to be mountable in a capsule, the diameter and thickness of the core 11 are set in consideration of this.

  The lower lid 17 and the upper lid 18 are formed in a thin disk shape having a size capable of covering the lower surface and the upper surface of the core 11. A terminal 19 for supplying power to the outside is provided in a predetermined region of the upper lid 18.

  The core 11, the lower lid 17 and the upper lid 18 are made of a material having high magnetic permeability, and can be made of, for example, high magnetic permeability ceramics. Examples of the high magnetic permeability ceramic include Mn—Zn, Mn—Mg—Zn, Mg—Cu—Zn, Ni—Zn, and Ni—Cu—Zn that are soft ferrites. Since the required performance differs depending on the frequency used, the high permeability ceramic is appropriately selected and used so as to match the target frequency. For example, when used at a frequency of 100 kHz, Mn—Zn soft ferrite is effective in terms of low loss.

  The lower lid 17 and the upper lid 18 may be made of an epoxy resin containing magnetic powder (hereinafter referred to as magnetic resin) in addition to the high magnetic permeability ceramics.

  The power receiving coil 12 wound around the side surface of the core 11 is preferably made of a metal material having a low resistivity such as Cu, Ag, or W. For example, a litz wire coated with a resin on a Cu wire is used as a conductive wire. be able to. For example, Cu or the like is used for the terminal 19 that supplies power to the outside.

  As shown in FIG. 3, the power receiving device 10 of the first embodiment can be mounted on a capsule-type housing 110 and used as a power receiving device-mounted capsule 100. The power receiving device mounting capsule 100 is applied to, for example, a capsule endoscope. Generally, the capsule casing 110 is made of resin, and the outer diameter Φ is about 11 mm and the length L is about 25 mm. In this case, the inner diameter of the capsule casing 110 is about 9 mm.

In order to be mounted on the capsule casing 110 having such a size, the size of the power receiving device 10 of the first embodiment is limited. As shown in the side view of FIG. 4, in the power receiving device 10 of the first embodiment, the diameter d _Lid of the lower lid 17 and the upper lid 18 can be slightly larger than the diameter d _{Core of the} core 11. In this case, the diameter d _{Core of the} core 11 is preferably about 6 to 9 mm, and the diameter d _Lid of the lower lid 17 and the upper lid 18 can be about 7 to 9 mm. By carrying out like this, it can accommodate in a capsule. The thickness t of the power receiving device 10 can be about 2 to 4 mm.

The lower lid 17 and the upper lid 18 are preferably thin as long as strength can be secured from the viewpoint of downsizing. However, in order to increase the effect of collecting the lines of magnetic force, the lower lid 17 and the upper lid 18 should be thicker. For example, the thicknesses t _L and t _U of the lower lid 17 and the upper lid 18 can be about 0.2 to 2 mm.

  As shown in FIG. 5, the capacitor module 13 includes a storage capacitor 13 b and a module 13 a disposed on the storage capacitor 13 b, and is stored in a storage portion 21 provided in the core 11. The accommodating part 21 has a shape and a size suitable for the capacitor module 13. In FIG. 5, the accommodating portion 21 is formed as a through hole penetrating to the lower surface of the core 11, but is not limited to this.

  A wiring 22 is provided in a predetermined region on the upper surface of the core 11. The capacitor module 13 accommodated in the accommodating portion 21 and the power receiving coil 12 wound around the side surface of the core 11 can be electrically connected via the wiring 22.

  Here, the state which looked at the capacitor module 13 from the module 13a side is shown in FIG. In the module 13 a, a chip component group 14 is provided in a ceramic case 16. For example, alumina is used as the ceramic constituting the casing 16. Although not shown, the chip component group 14 includes a resonance circuit (matching circuit), a rectifier circuit, a protection circuit, and the like. The resonant circuit includes, for example, a resonant capacitor and an inductor, and the rectifier circuit includes, for example, a Schottky diode, but is not limited thereto. The module 13a can be configured using any circuit component. The dimension of the module 13a can be appropriately determined according to the dimension of the core 11. When the diameter of the core 11 is about 9 mm, the size of the module 13a can be set to 5.8 mm × 5.8 mm × 1.6 mm.

  In FIG. 7, the state which looked at the capacitor module 13 from the electrical storage capacitor 13b side is shown. A kovar LID 23 is attached to a seam welding seal ring 24 on the capacitor 13 b side of the capacitor module 13. As the storage capacitor 13b, an electric double layer capacitor or a Li ion secondary battery having a large storage capacity is preferable. The electric double layer capacitor that can be charged in an extremely short time is more suitably used as the storage capacitor 13b in the power receiving device 10 of the first embodiment.

2. Manufacturing Method In the power receiving device 10 according to the first embodiment, the lower lid 17 is disposed on the lower surface of the core 11 having the housing portion 21, the power receiving coil 12 is wound around the side surface, and the capacitor module 13 is placed in the housing portion 21. Can be manufactured by placing the upper lid 18 on the upper surface of the core 11. Details will be described below.

<Preparation of core, lower lid, and upper lid>
The core 11 can be manufactured by sintering by a conventional method using a predetermined raw material powder. In producing the core 11, the accommodating portion 21 for accommodating the capacitor module 13 is formed using a mold having an appropriate shape. The shape and dimensions of the housing portion 21 may be designed in accordance with the outer shape and dimensions of the capacitor module 13 so that the capacitor module 13 is fixed without moving in the housing portion 21. The capacitor module 13 may be fixed to the housing portion 21 with resin or the like.

  The lower lid 17 and the upper lid 18 can be produced by a conventional method using the same raw material powder as that of the core 11 or a predetermined magnetic resin. A terminal 19 for supplying power to the outside is formed in a predetermined region of the upper lid 18 using metal vapor deposition, electrolytic plating, baking printing of a metal particle paste, or the like.

<Join the lower lid>
The lower lid 17 can be adhered and fixed to the lower surface of the core 11 using a resin, but preferably a magnetic resin is used.

<Formation of power receiving coil>
The power receiving coil 12 can be formed by winding a predetermined conductive wire around the side surface of the core 11. The number of windings and the line width of the power receiving coil 12 can be determined as appropriate. When using a heat-resistant resin-coated conductive wire exceeding 200 ° C., it is safer to make the resin film thicker, and the diameter including the resin film is generally about 100 μm.

  On the upper surface of the core 11 around which the power receiving coil 12 is wound, a wiring 22 for connecting to the capacitor module 13 so as to reach a predetermined region of the housing portion 21 from a predetermined region at the end of the power receiving coil 12. Form. The wiring 22 can be formed by, for example, electrode printing with a sintered metal paste using a dispenser, electrolytic plating, metal deposition, or the like.

<Production of capacitor module>
The capacitor module 13 can be manufactured by combining the module 13a and a predetermined storage capacitor 13b. In order to electrically connect the storage capacitor 13b and the module 13a, for example, as shown in FIG. 8, electrode wiring 25 provided on the surface along the outer edge of the ceramic casing 16 constituting the module 13a is used. be able to. Alternatively, so-called metallized wiring may be used in which a metal film is formed on the side surface of the ceramic casing 16 and etched.

  On the module 13a side, a chip component group 14 including a resonance capacitor or the like is arranged, and the capacitor module 13 is obtained.

<Accommodating capacitor module>
As shown in FIG. 9, the capacitor module 13 is accommodated in the accommodating portion 21 of the core 11 in which the power receiving coil 12 is wound on the side surface and the lower lid 17 is disposed on the lower surface. The electrode (not shown) of the capacitor module 13 is arranged in alignment with the wiring 22 on the upper surface of the core 11. The capacitor module 13 can be fixed in the housing portion 21 using a magnetic resin. The magnetic resin can also be used to fill a gap generated in the housing portion 21.

<Join the top lid>
An upper lid 18 is joined to the upper surface of the core 11 in which the capacitor module 13 is accommodated in the accommodating portion 21. As shown in FIG. 10, the terminals 19 on the upper lid 18 are arranged in alignment with the wirings 22 on the upper surface of the core 11. The upper lid 18 can be fixed to the upper surface of the core 11 using a magnetic resin. It is preferable to use an Ag nano paste having a heat resistant temperature comparable to that of an epoxy resin at a place where electrical connection is required.

  As described above, the capacitor module 13 is provided inside the main body 20 including the core 11, the lower lid 17, and the upper lid 18, and the power receiving coil 12 is wound around the side surface of the main body 20. The power receiving device 10 of the embodiment is obtained.

  The power receiving device 10 of the first embodiment can be mounted on the capsule-type housing 110 and fixed with, for example, silicon resin to obtain the power receiving device-mounted capsule 100. Appropriate components such as a CCD camera and a white LED can be arranged in the capsule casing 110 and applied to a human body-embedded capsule, a capsule endoscope, or the like.

3. Action and Effect In the power receiving device 10 of the first embodiment, a capacitor module 13 including a module 13a including a resonance capacitor and a storage capacitor 13b is provided inside a main body 20 formed of a material having high magnetic permeability. Yes. In the power receiving device 10 of the first embodiment, the capacitor module 13 is magnetically shielded by being provided in the main body 20 formed of a material having high magnetic permeability.

  When power is transmitted from the power transmission device 6 to the power receiving device 10, the magnetic field lines are formed so as to pass through the main body 20 formed of a material having high magnetic permeability, that is, the upper lid 18, the core 11, and the lower lid 17. Is done. In other words, in the power receiving device 10 of the first embodiment, the path of the lines of magnetic force is formed avoiding the capacitor module 13 provided inside the main body 20. Where a capacitor such as the storage capacitor 13b included in the capacitor module 13 includes a metal part such as an envelope or a current collector, the magnetic lines of force do not reach such a metal part. Therefore, the generation of induced current (voltage) due to the metal parts can be avoided. As a result, in the power receiving device 10 of the first embodiment, the possibility that the magnetic field lines are canceled by the induced current is reduced, and the power receiving efficiency is increased. At the same time, the magnetic lines of force gather in a material having a high magnetic permeability, so that the lines of magnetic force passing through the power receiving coil 21 increase. Also by this, power receiving efficiency can be improved.

  On the other hand, since the power receiving coil 12 in the power receiving device 10 of the first embodiment is wound around the side surface of the main body 20, specifically, the side surface of the core 11, the opening diameter of the power receiving coil 12 is outside the core 11. The size can correspond to the diameter. As shown in FIG. 3, when the power receiving device 10 of the first embodiment is used for mounting a capsule, the internal space of the capsule casing 110 is utilized to the maximum, The power receiving coil 12 can be formed with an opening diameter close to the inner diameter.

  As described above, in the power receiving device 10 of the first embodiment, the capacitor including the metal component is provided inside the main body 20 as the capacitor module 13, and the power receiving coil 12 is wound around the side surface of the main body 20. . Therefore, there is no component that shields the magnetic field lines reaching the power receiving coil 12. Even when the capsule equipped with such a power receiving device 10 moves in the human body and changes its direction with respect to the magnetic field lines, the magnetic field lines surely reach the power receiving coil 12 to receive power.

  In addition, since components (such as a resonance capacitor) other than the power receiving coil 12 are provided in the main body 20 as an integrated capacitor module 13, the size of the power receiving device 10 is substantially the core 11 constituting the main body 20. Is determined by the size of By using the small core 11, it is possible to reduce the size of the power receiving device 10, and the power receiving device 10 according to the first embodiment is suitably used for mounting a capsule.

[Second Embodiment]
1. Configuration FIG. 11 is an exploded perspective view of the power receiving device 30 according to the second embodiment. The power receiving device 30 shown in FIG. 11 has the same configuration as the power receiving device 10 of the first embodiment, except that the upper lid 18 is changed to an upper lid 27 that acts as a mechanical resonator.

  The upper lid 27 acting as a mechanical resonator includes a diaphragm 32 and a permanent magnet 31 placed in a predetermined region of the diaphragm 32. The diaphragm 32 can be made of a high permeability ceramic similar to the core 11 and includes a vibration portion 32b in the central region and a support portion 32a in the peripheral region. A gap portion 33 exists between the support portion 32a and the vibration portion 32b, and the vibration portion 32b is joined to the support portion 32a by a hinge 32c provided in a predetermined region on the outer periphery. The permanent magnet 31 is placed on the vibrating part 32b.

The permanent magnet 31 can be magnetically coupled to the power receiving coil 12 wound around the side surface of the core 11. The permanent magnet 31 is preferably a permanent magnet having a high electrical resistivity of 10 × 10 ² Ω · cm or higher. Specifically, the permanent magnet 31 can be selected from a barium ferrite magnet, a strontium ferrite magnet, a bond magnet, and the like.

  As described in the first embodiment, the capacitor module 13 is accommodated in the core 11, and the capacitor module 13 includes a module including a matching circuit and the like.

  Here, a matching circuit using a mechanical resonator will be described with reference to an equivalent circuit. FIG. 12 shows an equivalent circuit including a mechanical resonator and a coil. The left side of FIG. 12 represents an equivalent circuit of a mechanical resonator including an electrical converter. The electrical conversion unit specifically refers to an RLC circuit. The equivalent circuit shown in the figure is configured with the following conditions.

A diaphragm with mass m ₀ is supported by a spring with compliance c _0. A current I flows through a coil with inductance L ₀ to generate a magnetic field. A permanent magnet on the diaphragm receives the generated magnetic field. Receives a force kI (k is a coupling coefficient)-The diaphragm on which the permanent magnet is mounted vibrates at a speed v-This generates an induced voltage kv

Incidentally, g ₀ in the figure represents the mechanical resistance (resistance / speed). In the above, v and I represent phaser display values.

Also, _V appearing _{below, f, V e, B 0} , V 0, I 0, I 1, I 2 also represents the value of the phaser display.

When the configuration of FIG. 12 is made to correspond to the configuration of FIG. 11, the diaphragm with mass m ₀ corresponds to the total mass of the vibration part 32b and the permanent magnet 31, and the spring with compliance c ₀ corresponds to the hinge 32c. The coil and the permanent magnet correspond to the power receiving coil 12 and the permanent magnet 31, respectively. Further, the mechanical resistance g ₀ corresponds to the sum of the mechanical resistance of the hinge 32 c in FIG. 11 and the air resistance of the vibration part 32 b and the permanent magnet 31.

  Here, each frequency at which the external magnetic field vibrates is ω, and an imaginary unit is j.

In the equivalent circuit on the left side of FIG. 12, the force f applied to the permanent magnet can be described as follows.

Therefore, the velocity v of the diaphragm is as follows.

As the external magnetic field changes with time, a voltage _Ve is generated in the coil. External magnetic flux density B _0, the area of the coil S, the use of the number of turns N, the voltage V _e which is generated in the coil is expressed by the following equation.

The coil also generates a voltage kv (k is a coupling coefficient) according to the moving speed v of the permanent magnet. Considering this voltage kv, the electromotive force V ₀ appearing in the coil can be described as follows.

Here, the equivalent current source I ₀ , the equivalent capacitance C _k , the equivalent inductance L _k , and the equivalent resistance R _k are defined as follows.

  At this time, an equivalent circuit when the left side is viewed from the terminal A-A 'in FIG. 12 is shown in FIG. 13A. FIG. 13A shows an equivalent circuit 40 of a mechanical resonator including an electric converter, and FIG. 13B shows an equivalent circuit 41 at the time of resonance as will be described later. FIG. 13 is an electrical equivalent circuit including a mechanical resonator and a coil.

FIG. 13A can be converted to FIG. 13B using the equivalent power supply theorem as described below during resonance. First, the load short-circuit current I ₁ and the equivalent admittance Y _in can be described as follows.

At the time of resonance, the following relationship is established.

Accordingly, the load short-circuit current I ₁ and the equivalent admittance Y _in at resonance can be described as follows.

An equivalent circuit having such load short-circuit current I ₁ and equivalent admittance Y _in is as shown in FIG. 13B.

Consider a case where an external electric circuit including a load as shown in FIG. 14 is provided. As shown in FIG. 14, an equivalent circuit 43 of a mechanical resonator at the time of resonance and an external electric circuit 44 are included. In FIG. 14, the load admittance Y _L as viewed from AA ′ to the right is matched when the following is satisfied.

That is, R _k is converted to (ωL ₀ ) ² / R _k .

Here, the Q value of the mechanical resonator is ωm ₀ / g ₀ , and the Q value when converted into an electric circuit can be described as follows.

Therefore, if the following relationship is satisfied, the Q value when converted to an electric circuit is small, and even if the electric circuit is configured with elements having a low Q value, the loss can be kept low.

Here, if the .omega.L ₀ and the following values, can be matched with one element of C _L.

If it is difficult to freely set the value of the coil inductance L ₀ due to restrictions on the mechanical-electrical conversion mechanism, an external electric circuit may be further added to perform impedance matching.

FIG. 15 shows an example of impedance matching using susceptances b ₁ and b ₂ and reactance x ₁ . FIG. 15 includes a resonance equivalent circuit 46 after electrical conversion of mechanical vibration and a matching circuit 47.

Similarly to the calculation for FIG. 13, the load short-circuit current I ₂ and the admittance Y _in2 when the left side is expected from BB ′ in FIG. 15 can be described as follows.

Also in this case, when resonating, the following relationship is established.

Therefore, the load short-circuit current I ₂ and the equivalent admittance Y _in2 at resonance can be described as follows.

Load resistor R _L and susceptance b ₂ in FIG. 15 can matching satisfies the following relationship.

Since the susceptances b ₁ and b ₂ and the reactance x ₁ are electric circuit elements, values can be selected relatively freely within a range in which the Q value does not decrease.

By making the reactance x ₁ smaller than the impedance ωL ₀ , matching to a low load resistance is possible even if 1 / R _k and ωL ₀ are small.

In FIG. 15, the portion obtained by combining b ₁ and x ₁ in the matching circuit 47 with the equivalent circuit 46 has the same form as FIG. 13A. By obtaining the resonance conditions in the same procedure as in FIG. 13, it is possible to configure a multi-stage matching circuit and increase the degree of freedom in selecting circuit elements.

The susceptances b ₁ , b ₂ , reactance x _{1 and the} like in the electric circuit are merely examples for explanation, and an inductor can be used instead of the capacitor. Conversely, a capacitor may be used instead of the inductor. Furthermore, other mechanical resonators can be used for the reactance x ₁ or the like. In any case, the matching circuit can be appropriately set by obtaining the resonance condition in the same manner as described above.

  In the above description, as an example using a mechanical resonator, an induced current is generated in the receiving coil 12 due to the vibration of the external magnetic field, and the permanent magnet 31 is vibrated by the generated induced current. The case where the induced current is generated in (pattern 1) has been described. When a mechanical resonator is used, the permanent magnet 31 vibrates by directly receiving the vibration of the external magnetic field, and an induced current may be generated in the power receiving coil 12 due to the vibration of the permanent magnet 31 (pattern 2). . Such (Pattern 2) can occur simultaneously with the (Pattern 1) described above. In the case of the pattern 2 as well, an optimum matching circuit may be set by obtaining the resonance condition in the same manner as described above.

2. Manufacturing Method In the power receiving device 30 according to the second embodiment, an upper lid 27 that functions as a mechanical resonator is used.

  The diaphragm 32 in the upper lid 27 can be produced by sintering by a conventional method using a predetermined raw material powder. Using a mold having an appropriate shape, the support portion 32a and the vibration portion 32b are connected by the hinge 32c. What is necessary is just to set the magnitude | size of the vibration part 32b suitably according to the magnitude | size of the permanent magnet 31. FIG. In order not to disturb the vibration of the permanent magnet 31, it is desirable that the vibration part 32b and the hinge 32c be as thin as possible within a range where the strength can be maintained. The area of the gap portion 33 is preferably small as long as the vibrating portion 32b can swing freely up and down so as not to disturb the vibration of the permanent magnet 31.

  The diaphragm 32 need not be entirely made of high permeability ceramics. The diaphragm 32 may be configured by forming a thin film of high permeability ceramics on the surface of a substrate having high resistance. As a board | substrate with high resistance, semiconductor crystals, such as a high resistance Si substrate, a SiC substrate, and a sapphire substrate, are mentioned, for example. A thin film such as silicon nitride or silicon oxide may be formed on such a substrate. In particular, the Si substrate has a high fine workability, and a MEMS resonator including a membrane, a hinge, and the like is manufactured. Even when the diaphragm 32 is formed by forming a thin film of high permeability ceramics on the substrate, it is desirable that the substrate is as thin as possible within a range where the strength can be maintained so as not to disturb the vibration of the permanent magnet 31. The thin film of high magnetic permeability ceramic can be formed on the surface of the substrate by sputtering, for example.

  The permanent magnet 31 can be fixed to the vibration part 32a of the vibration plate 32 using an epoxy adhesive or the like.

  The gap portion 33 between the vibrating portion 32b and the support portion 32a connected by the hinge 32c can be filled with a magnetic resin. As the magnetic resin, those already described can be used. When arranging the magnetic resin, it is desirable to take care not to disturb the vibration of the vibration part 32b.

  The power receiving device 30 according to the second embodiment can be manufactured basically in the same manner as in the first embodiment except that the upper lid 27 acting as a mechanical resonator thus manufactured is used. .

3. Action and Effect In the power receiving device 30 of the second embodiment, the capacitor module 13 including the module 13a including the resonance capacitor and the storage capacitor 13b is provided inside the main body 20 formed of a material having high magnetic permeability. The power receiving coil 12 is wound around the side surface of the main body 20, specifically, the side surface of the core 11.

  As in the case of the power receiving device 10 of the first embodiment, also in the power receiving device 30 of the second embodiment, the path of the magnetic force lines is formed avoiding the capacitor module 13, and therefore there is a possibility that the magnetic force lines are canceled by the induced current. The power receiving efficiency is increased by reducing the power receiving efficiency. The power receiving device 30 according to the second embodiment is also characterized in that the opening diameter of the power receiving coil 12 is large, the lines of magnetic force to the power receiving coil 12 are not blocked, and that the size can be reduced. The same effect is obtained as in the case of.

  Moreover, the power receiving device 30 of the second embodiment includes an upper lid 27 that functions as a mechanical resonator. In the upper lid 27, the permanent magnet 31 is placed on the vibration part 32 a of the diaphragm 32. When the power receiving device 30 according to the second embodiment receives an external magnetic field, an induced current is generated in the power receiving coil 12 that is wound around the side surface of the core 11. A magnetic field is formed. In response to the magnetic field generated in this way, the permanent magnet 31 on the vibration part 32 a vibrates, and thereby further induces a current in the power receiving coil 12.

  In the power receiving device 30 of the second embodiment, the permanent magnet 31 receives a magnetic field and vibrates, thereby generating an induced current in the power receiving coil 12. The magnetic field acting on the permanent magnet 31 is formed by an induced current generated in the receiving coil 12 by receiving an external magnetic field. Thus, the Q value is increased by using the upper lid 27 acting as a mechanical resonator including the diaphragm 32 and the permanent magnet 31, and the power receiving efficiency is further enhanced.

[Modification]
The present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope of the gist of the present invention.

  In the first embodiment, the core is disc-shaped, but the shape of the core is not limited to the disc shape. The core may have a shape other than a disk shape as long as the housing module can be formed to accommodate the capacitor module therein and the power receiving coil can be wound around the side surface. A core having an arbitrary shape can be used as long as it can be mounted on the capsule housing.

  The power receiving coil is formed by winding a conductive wire around the side surface of the core, but may be formed by printing and baking a sinterable metal paste on the side surface of the core. For example, coil printing is possible by moving the dispenser at a constant speed while discharging the metal paste from the dispenser onto the side surface of the rotating cylindrical core. Also in this case, the number of turns of the power receiving coil, the line width, and the like can be determined as appropriate. However, since it is printed as a single stroke with a predetermined distance between lines so as not to be short-circuited, the inductance value design is restricted. On the other hand, the insulating resin-coated conductive wire is advantageous in that it can be densely wound or overlapped by using a manual winding machine or an automatic winding machine. When W paste is used, it is preferable to form an Ag or Au plating film after firing in order to lower the resistivity.

  Moreover, although the thing of a larger diameter than a core was used as an upper cover and a lower cover, you may make it the same magnitude | size as the diameter of a core. The same applies to the case where the core has a shape other than the disk shape, and this point is also applied to the second embodiment.

  Furthermore, in the second embodiment, the upper lid 27 acting as a mechanical resonator can be changed as follows. For example, like the upper cover 35 shown in FIG. 16, you may change to the diaphragm 36 in which the permanent magnet 31 is mounted. In the illustrated diaphragm 36, two opposing sides of the vibration part 36b are directly connected to the support part 36a. FIG. 17 is a cross-sectional view taken along the line C-C ′ in FIG. The vibration part 36b on which the permanent magnet 31 is placed is smaller in thickness than the support part 36a, and two specific sides of the vibration part 36b are directly connected to the support part 36a. For this reason, the permanent magnet 31 swings up and down using the warp of the vibration part 36b. Even when the permanent magnet 31 is greatly shaken and the vibrating portion 36b is vibrated greatly, the influence on the entire upper lid 35 is reduced.

  Further, like the upper lid 37 shown in FIG. 18, two opposing sides of the vibrating part 32b on which the permanent magnet 31 is placed are formed longer than the other two sides, and a predetermined part of the vibrating part 32b along the short side is formed. A balancer (weight) 38 may be arranged in the region. Such a vibration part 32b is connected to the support part 32a at the long side by a hinge 32c. FIG. 19 is a cross-sectional view taken along the line D-D ′ of the vibration part 32 b in FIG. Since the balancer (weight) 38 is provided on the vibration part 32 b, the hinge 32 c receives a torsional force, and the vibration of the permanent magnet 31 is hardly transmitted to the entire upper lid 37. Furthermore, since the vibration of the permanent magnet 31 is not easily transmitted to the core where the upper lid 37 is disposed, the Q value is increased.

  By reducing the vibration of the upper lid, the vibration of the entire power receiving apparatus can also be reduced. Since the power receiving device mounting capsule in which such a power receiving device is mounted in a capsule-type housing is suppressed in vibration, there is an advantage that a stable image can be obtained when applied to a capsule endoscope or the like. It is done.

DESCRIPTION OF SYMBOLS 10,30 Power receiving device 11 Core 12 Power receiving coil 13 Capacitor module 13a Module 13b Storage capacitor 17 Lower lid 18, 27 Upper lid 19 Terminal 20 Main body 100 Power receiving device mounting capsule 110 Capsule type housing

Claims (4)

A power receiving device that acquires power from a power transmitting device that transmits non-contact power,
A body made of a material with high magnetic permeability,
A capacitor module provided in the main body;
A power receiving coil that is wound around a side surface of the main body and electrically connected to the capacitor module;
The capacitor module is
A module including a resonant capacitor and a rectifier circuit that constitute a resonant circuit together with the power receiving coil;
A power receiving device including a power storage capacitor for storing electric power.   The power receiving device according to claim 1, wherein the main body includes a mechanical resonator. The mechanical resonator is
A diaphragm,
The power receiving device according to claim 2, further comprising a permanent magnet mounted on the diaphragm and magnetically coupled to the power receiving coil.   A power receiving device mounting capsule, wherein the power receiving device according to any one of claims 1 to 3 is mounted in a capsule casing.