JP2013179721A - Power transmission element and power transmission apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission element that continuously generates electric power even when energy is intermittently applied.SOLUTION: The power transmission element 21 constitutes a power transmission apparatus 1 together with an electric-magnetic conversion element 11. The power transmission element 21 includes a vibrator 23 and a piezoelectric element 24. The piezoelectric element 24 is installed on the vibrator 23. At least a part of the vibrator 23 is formed from a magnetic substance.

Description

  The present invention relates to a power transmission element and a power transmission device including the power transmission element. In particular, the present invention relates to a power transmission element using a piezoelectric element and a power transmission device including the power transmission element.

  Conventionally, for example, in Patent Documents 1 to 3 listed below, a power transmission device that transmits power without being directly electrically connected has been proposed.

  Specifically, Patent Documents 1 and 2 propose a power transmission device that transmits power from the power feeding side to the power receiving side by converting vibration of the power feeding side piezoelectric element into electric power in the power receiving side piezoelectric element. Has been.

  Patent Document 3 proposes a power transmission device in which power is induced in the power receiving side coil by electromagnetically coupling the power feeding side coil and the power receiving side coil, and power is transmitted from the power feeding side to the power receiving side. ing.

WO00 / 38296 JP 2002-84688 A JP-A-8-79976

  In the power transmission device using the piezoelectric element described in Patent Documents 1 and 2, power is generated in the power receiving side piezoelectric element only when the vibration of the power feeding side piezoelectric element propagates to the power receiving side piezoelectric element. Therefore, in order to continuously generate power in the power receiving side piezoelectric element, it is necessary to continuously supply power to the power feeding side piezoelectric element.

  In addition, when the power feeding side piezoelectric element and the power receiving side piezoelectric element are arranged apart from each other, theoretically, power transmission can be continuously performed by intermittent energy application. However, it is virtually impossible for the following reasons. That is, even if an attempt is made to excite another solid vibration due to the air propagation of the solid vibration, the acoustic impedance is greatly different between the air and the solid, so the energy transfer efficiency between the solid and the air is very low. Therefore, in the power transmission device using the piezoelectric element described in Patent Documents 1 and 2, it is necessary to reliably contact the power feeding side piezoelectric element and the power receiving side piezoelectric element. For example, when the power feeding side piezoelectric element and the power receiving side piezoelectric element are arranged via a space, energy transmission is not substantially performed. Therefore, the power feeding side piezoelectric element and the power receiving side piezoelectric element cannot be arranged separately. Therefore, the power transmission devices of Patent Documents 1 and 2 cannot continuously perform power transmission by intermittent energy application.

  Moreover, in the power transmission device using the electromagnetic coil described in Patent Document 3, power is generated in the power receiving side coil only when the power receiving side coil and the power feeding side coil are electromagnetically coupled. For this reason, in order to generate electric power continuously in the power receiving side coil, it is necessary to continuously supply power to the power feeding side coil.

  This invention is made | formed in view of this point, The objective is to provide the electric power transmission element which can generate electric power continuously even when it is a case where energy is provided intermittently.

  A power transmission element according to the present invention is a power transmission element that constitutes a power transmission device together with an electric-magnetic conversion element. The power transmission element according to the present invention includes a vibrating body and a piezoelectric element. The piezoelectric element is attached on the vibrating body. At least a part of the vibrating body is made of a magnetic material.

  In a specific aspect of the power transmission element according to the present invention, the power transmission element is a power receiving element that generates electric power in the piezoelectric element when the vibrating body vibrates due to electromagnetic energy supplied from the electro-magnetic conversion element. .

  In another specific aspect of the power transmission element according to the present invention, the power transmission element is a power feeding element that supplies electromagnetic energy to the electro-magnetic conversion element by vibrating the vibrating body when the piezoelectric element vibrates.

  In another specific aspect of the power transmission element according to the present invention, the vibrating body includes a vibrating body main body and a magnetic member. The vibrating body main body has first and second main surfaces. A piezoelectric element is attached on the first main surface of the vibrating body. The magnetic member is attached on a portion of the second main surface of the vibrating body that faces the piezoelectric element.

  The power transmission device according to the present invention includes a first power transmission element and a second power transmission element. The first power transmission element has an electro-magnetic conversion element. The second power transmission element transmits power to and from the first power transmission element. The second power transmission element includes a vibrating body and a piezoelectric element. The piezoelectric element is attached on the vibrating body. At least a part of the vibrating body is made of a magnetic material. At the time of power transmission, the electro-magnetic conversion element and at least a part of the vibrating body magnetic body are arranged so that the electro-magnetic conversion element and at least a part of the vibrating body magnetic body are electromagnetically coupled. The

  In a specific aspect of the power transmission device according to the present invention, the electro-magnetic conversion element and the second power transmission element are arranged apart from each other.

  In another specific aspect of the power transmission device according to the present invention, the power transmission device further includes a control unit that intermittently supplies power to the electro-magnetic conversion element or the piezoelectric element. According to this configuration, electric power can be continuously transmitted by intermittently supplying electric power to the piezoelectric element. Therefore, power transmission can be performed with high energy efficiency.

  In another specific aspect of the power transmission device according to the present invention, the control unit intermittently supplies power to the electro-magnetic conversion element. The control unit supplies power to the electro-magnetic conversion element such that the power supply cycle to the electro-magnetic conversion element is longer than the reciprocal of the resonance frequency of the first power transmission element.

  In still another specific aspect of the power transmission device according to the present invention, the power transmission device further includes a detection unit that detects vibration of the first power transmission element or a generated voltage in the piezoelectric element. The control unit intermittently supplies power to the electro-magnetic conversion element. The control unit adjusts the power supply cycle to the electro-magnetic conversion element so that the vibration efficiency of the first power transmission element is improved based on the detection result of the detection unit. According to this configuration, the energy efficiency of power transmission can be further increased.

  In yet another specific aspect of the power transmission device according to the present invention, the control unit changes the period of supplying power to the electro-magnetic conversion element while the detection unit vibrates the first power transmission element or the piezoelectric element. By detecting the power generation voltage at, the amplitude of vibration of the first power transmission element or the power supply period to the electro-magnetic conversion element at which the power generation voltage at the piezoelectric element is maximized is detected, and the electric power is supplied at the power supply period. -Supply power to the magnetic transducer. According to this configuration, the energy efficiency of power transmission can be further increased.

  In still another specific aspect of the power transmission device according to the present invention, the control unit vibrates the vibrating body by applying power to the piezoelectric element. According to this configuration, for example, when power transmission is not performed, the piezoelectric element can be used as a vibrator or a speaker.

  In the present invention, power transmission is performed by electromagnetic coupling between the electro-magnetic conversion element and at least a part of the vibrating body made of a magnetic material. For example, when the electro-magnetic conversion element is on the power feeding side, the vibrating body vibrates due to electromagnetic coupling with the electro-magnetic conversion element. As a result, electric power is generated in the piezoelectric element. In this case, since the electric power continues to be generated in the piezoelectric element while the vibrating body vibrates, the electric power is intermittently supplied to the electric-magnetic conversion element, and the electric power is supplied to the electric-magnetic conversion element. Even if there is a period during which the vibration body is not used, power generation by the piezoelectric element is performed during the period in which the vibrating body continues to vibrate.

  For example, when the electro-magnetic conversion element is on the power receiving side, electric power is supplied to the piezoelectric element, and the piezoelectric element and the vibrating body vibrate to generate electric power in the electro-magnetic conversion element. In this case, while the vibrating body vibrates, electric power continues to be generated in the electro-magnetic conversion element, so that the power supply to the piezoelectric element is intermittently performed and the power supply to the piezoelectric element is not performed. Even if there is, power generation by the electro-magnetic conversion element is performed during the period in which the vibrating body continues to vibrate.

  Therefore, in the present invention, electric power can be continuously generated even when energy is intermittently applied.

It is a schematic diagram showing the structure of the electric power transmission apparatus which concerns on 1st Embodiment. It is a time chart of the pulse voltage applied to the electromagnetic coil in the 1st electric power transmission mode in a 1st embodiment, and vibration of a receiving element. It is a time chart of the pulse voltage applied to the electromagnetic coil in the 2nd electric power transmission mode in a 1st embodiment, and vibration of a receiving element. It is a schematic diagram showing the structure of the electric power transmission apparatus which concerns on 2nd Embodiment. It is a schematic diagram showing the structure of the electric power transmission apparatus which concerns on 3rd Embodiment. It is a schematic diagram showing the structure of the electric power transmission apparatus which concerns on 4th Embodiment. It is a schematic side view showing the principal part of the power receiving apparatus in a 1st modification. FIG. 8 is a schematic cross-sectional view taken along line VIII-VIII in FIG. 7. It is a schematic perspective view showing the principal part of the power receiving apparatus in a 2nd modification. It is the schematic perspective view which expanded a part of power receiving device in the 2nd modification. It is a schematic side view showing the principal part of the power receiving apparatus in the 3rd modification.

  Hereinafter, a preferred embodiment in which the present invention is implemented will be described by taking the power transmission apparatuses 1 and 2 shown in FIGS. 1 and 4 as examples. However, the power transmission devices 1 and 2 are merely examples. The present invention is not limited to these power transmission devices 1 and 2.

(First embodiment)
FIG. 1 is a schematic diagram illustrating a configuration of a power transmission device 1 according to the first embodiment.

  A power transmission device 1 illustrated in FIG. 1 is a device used when power transmission is performed in a state where the cellular phone is not directly electrically connected, such as charging a mobile phone. The power transmission device 1 includes a power feeding device 10 and a power receiving device 20.

  The power feeding device 10 and the power receiving device 20 can be separated. For example, when the power transmission device 1 is applied to a mobile phone charging system, the power supply device 10 is provided in the charger, and the power receiving device 20 is provided in the mobile phone. When charging a mobile phone, the power feeding device 10 and the power receiving device 20 are arranged close enough to allow electromagnetic coupling. Note that the power feeding device 10 and the power receiving device 20 may be fixed in a state where they are close enough to be electromagnetically coupled by using a holding member capable of temporarily fixing the relative position between the power feeding device 10 and the power receiving device 20. . When the mobile phone is not charged, the power feeding device 10 and the power receiving device 20 are not necessarily arranged close to each other.

  However, both of the power feeding device 10 and the power receiving device 20 may be housed in one device that is inseparable.

  The power feeding device 10 is a device for applying energy to the power receiving device 20. Specifically, in the present embodiment, the power feeding device 10 is a device for applying electromagnetic energy to the power receiving device 20. The power feeding device 10 includes an electromagnetic coil 11 as a power feeding element, a detection mechanism 12 that detects vibration of the power receiving element 21 or a generated voltage in the piezoelectric element 24, and a control unit 13. In addition, the detection mechanism 12 can be comprised by an electromagnetic coil, a Hall element, a magnetoresistive element, etc., for example.

  On the other hand, the power receiving device 20 is a device that converts energy (specifically, electromagnetic energy) applied by the power feeding device 10 into electric power. The power receiving device 20 includes a power receiving element 21 supported by a housing 22 and a control unit 29.

  During power transmission, the power receiving element 21 is arranged so as to be separated from the electromagnetic coil 11 as a power feeding element. The power receiving element 21 includes a vibrating body 23. In the present embodiment, the vibrating body 23 is configured by a plate-like diaphragm. However, in the present invention, the shape of the vibrating body is not limited to the diaphragm.

  The vibrating body 23 is not particularly limited as long as it has elasticity and can vibrate. The vibrating body 23 can be formed of, for example, metal, ceramics, resin, or the like.

  The vibrating body 23 includes a vibrating body main body 23a, a support portion 23b that supports the vibrating body main body 23a, and a magnetic member 23c. In plan view, the piezoelectric element 24 is mounted on the surface of one side of the vibrating portion 23a1 that is located inside the support portion 23b in the vibrating body main body 23a. The piezoelectric element 24 includes a piezoelectric substrate 26 and first and second electrodes 25 and 27.

  The piezoelectric substrate 26 can be formed of an appropriate piezoelectric body. The piezoelectric substrate 26 can be formed of piezoelectric ceramics such as PZT (lead zirconate titanate) ceramics.

  The first and second electrodes 25 and 27 sandwich the piezoelectric substrate 26. The electromotive force generated in the piezoelectric substrate 26 is taken out from the first and second electrodes 25 and 27. The first and second electrodes 25 and 27 can be formed of an appropriate conductive material. The first and second electrodes 25 and 27 can be formed of, for example, a metal such as iron, copper, or aluminum, or an alloy such as stainless steel or duralumin.

  The magnetic member 23c is attached on the surface of the vibrating portion 23a1 opposite to the piezoelectric element 24. The magnetic member 23c is provided in the approximate center of the vibration part 23a1 in plan view. The magnetic member 23c is opposed to the piezoelectric element 24 via the vibration part 23a1. The magnetic member 23c is provided so as to be electromagnetically coupled to the electromagnetic coil 11 as a power feeding element during power transmission.

  The magnetic member 23c can be formed of an appropriate magnetic material. The magnetic member 23c can be formed of, for example, a metal such as iron or nickel, or an alloy containing iron or nickel.

  Next, an outline of power transmission in the power transmission device 1 of the present embodiment will be described.

  When power transmission is performed, the power feeding device 10 and the power receiving device 20 are arranged so that the magnetic member 23c and the electromagnetic coil 11 are electromagnetically coupled. In that state, the control unit 13 applies power to the electromagnetic coil 11. Thereby, the electromagnetic coil 11 and the magnetic member 23c are electromagnetically coupled. As a result, the flexible vibrating portion 23a1 of the vibrating member 23 to which the magnetic member 23c and the magnetic member 23c are attached vibrates. As the vibration part 23a1 is deformed by vibration, the piezoelectric element 24 also vibrates. As a result, distortion occurs in the piezoelectric substrate 26 of the piezoelectric element 24, and an electromotive force is generated in the piezoelectric element 24.

  As described above, in the power transmission device 1, when power is supplied to the electromagnetic coil 11 of the power feeding device 10, power is generated in the power receiving device 20 that is not electrically connected directly to the power feeding device 10. Thereby, electric power is transmitted. In addition, detailed operation | movement of the power transmission apparatus 1 of this embodiment is explained in full detail later.

  In the power transmission device 1 of the present embodiment, an electromotive force is generated in the piezoelectric element 24 when the vibrating body 23 vibrates due to electromagnetic energy supplied from the electromagnetic coil 11. An electromotive force is generated in the piezoelectric element 24 during the period in which the vibrating body 23 vibrates due to the restoring force. For this reason, even if there is a period in which power is intermittently supplied to the electromagnetic coil 11 and power supply to the electromagnetic coil 11 is not performed, in the period in which the vibrating body 23 continues to vibrate. Then, power generation by the piezoelectric element 24 is performed. Therefore, by supplying power to the electromagnetic coil 11 again while the vibrating body 23 continues to vibrate, it is possible to continuously perform power transmission while intermittently supplying power to the electromagnetic coil 11.

  By the way, for example, when power transmission is performed by converting vibration generated by the piezoelectric element on the power feeding side into electric energy by the piezoelectric element on the power receiving side, the vibration generated by the piezoelectric element on the power feeding side is transmitted. Need to propagate to.

  For example, it is conceivable that the vibration of the piezoelectric element on the power supply side is propagated as a sound wave to the piezoelectric element on the power reception side, but in this case, it is necessary to match the acoustic impedance, which causes a very large restriction. Further, when the vibration is propagated as a sound wave, the energy transmission efficiency is lowered, so that the power transmission efficiency is lowered. For this reason, when power transmission is performed using vibration propagation, it is necessary to directly contact the piezoelectric element on the power feeding side and the piezoelectric element on the power receiving side.

  However, when the piezoelectric element on the power feeding side and the piezoelectric element on the power receiving side are in direct contact with each other, when the vibration of the piezoelectric element on the power feeding side stops, the vibration of the piezoelectric element on the power receiving side is attenuated by the mass load of the power feeding side piezoelectric element. It's easy to do. For this reason, unlike the power transmission device 1 of the present embodiment, when power is not supplied to the piezoelectric element on the power feeding side, power transmission is not substantially performed.

  Further, when the power feeding side piezoelectric element and the power receiving side piezoelectric element come into contact with each other, these piezoelectric elements are likely to deteriorate with time.

  On the other hand, in the power transmission device 1 of the present embodiment, the electromagnetic coil 11 as the power feeding element and the power receiving element 21 are not in contact with each other. Therefore, the electromagnetic coil 11 and the power receiving element 21 are not easily damaged, and a long product life can be realized.

  For example, in the case of performing power transmission by converting the vibration generated by the piezoelectric element on the power feeding side into electrical energy by the piezoelectric element on the power receiving side, the shape of the contact surface of the power feeding side piezoelectric element and the power receiving side piezoelectric element It is necessary to correspond to the shape of the contact surface. For this reason, for example, if the power receiving device 20 is different, it may be impossible to transmit power.

  On the other hand, in the present embodiment, as long as the power receiving element 21 exists in the power receiving device 20, there is no restriction on the shape of the power receiving device 20, and power is transmitted to various power receiving devices 20 by the electromagnetic coil 11 as a power feeding element. Can do.

  Next, details of power transmission in the power transmission device 1 of the present embodiment will be described.

  The power transmission device 1 can perform power transmission in a plurality of different modes.

(First power transmission mode)
FIG. 2 is a time chart of the pulse voltage applied to the electromagnetic coil and the vibration of the power receiving element in the first power transmission mode in the first embodiment.

  The first power transmission mode is a mode in which the power transmission efficiency is increased although the magnitude of power generated in the power receiving device 20 is reduced. “Power transmission efficiency” is the ratio of output power to input power ((output power) / (input power)).

  In the first power transmission mode, the control unit 13 intermittently supplies power to the electromagnetic coil 11. Specifically, as shown in FIG. 2, the control unit 13 periodically applies a pulsed voltage to the electromagnetic coil 11. More specifically, the control unit 13 determines that the power supply cycle to the electromagnetic coil 11, that is, the pulsed voltage application cycle T 1 is the first vibration cycle of the power receiving element 21 when the pulsed voltage is applied, that is, Then, a voltage is applied to the electromagnetic coil 11 so as to be shorter than the reciprocal T2 of the resonance frequency of the power receiving element 21. Moreover, the application period T1 of the pulse voltage applied to the electromagnetic coil 11 by the control unit 13 is equal to or less than the time required for the vibration of the power receiving element 21 to be completely attenuated. That is, the control unit 13 controls the voltage intensity, the electric field direction, the application time length, the application cycle, and the like for exciting the next pulse voltage until the vibration of the power receiving element 21 is completely attenuated. Apply while. By doing in this way, electric power can be continuously transmitted with high electric power transmission efficiency, performing electric power supply intermittently.

(Second power transmission mode)
FIG. 3 is a time chart of the pulse voltage applied to the electromagnetic coil and the vibration of the power receiving element in the second power transmission mode according to the first embodiment.

  The second power transmission mode is a mode in which a large amount of power is generated in the power receiving device 20 although the power transmission efficiency is lower than that in the first power transmission mode.

  In the second power transmission mode, the control unit 13 causes the electromagnetic coil so that the application period T1 of the pulse voltage is equal to a value obtained by multiplying a half of the reciprocal T2 of the resonance frequency of the power receiving element 21 by a positive integer. 11 is applied with electric power. Furthermore, when the application period T1 is equal to the value obtained by multiplying the reciprocal T2 by an even number, there is an effect that the control law and the electric circuit are simplified because it is not necessary to change the sign of the applied electric field in order to prevent the vibration from being attenuated. preferable. For this reason, the power receiving element 21 vibrates at the resonance frequency, and the magnitude of the electric power generated in the power receiving element 21 at this time is maximized.

  For example, when the control unit 13 of the power supply device 10 stores the specification of the power receiving device 20, it is easy to make the application period T1 of the pulse voltage equal to the reciprocal T2 of the resonance frequency of the power receiving element 21. However, when the control unit 13 does not store the specification of the power receiving device 20, the pulse voltage application period T 1 and the inverse T 2 of the resonance frequency of the power receiving element 21 cannot be immediately matched.

  In the present embodiment, the control unit 13 first applies a pulse voltage having a predetermined period to the electromagnetic coil 11, and in that state, the detection mechanism 12 is caused to vibrate the power receiving element 21 or generate power in the piezoelectric element 24. Let the voltage be detected. And the control part 13 adjusts the electric power supply period T2 to the electromagnetic coil 11 so that the vibration efficiency of the power receiving element 21 improves based on the result.

  Alternatively, the control unit 13 causes the detection unit to detect the vibration of the power receiving element 21 or the generated voltage in the piezoelectric element 24 while changing the power supply cycle T <b> 2 to the electromagnetic coil 11. Based on the detection result, the control unit 13 detects the power supply period T2 at which the amplitude of vibration of the power receiving element 21 or the generated voltage in the piezoelectric element 24 is maximized. And the control part 13 supplies the electric power to the electromagnetic coil 11 with the detected electric power supply period T2.

  Therefore, in the present embodiment, even when the control unit 13 of the power supply apparatus 10 does not store the specification of the power receiving apparatus 20, power transmission can be performed with high power transmission efficiency.

(Functions other than power transmission of the power transmission device 1)
In the present embodiment, when power transmission is not performed, the control unit 29 of the power receiving apparatus 20 vibrates the vibrating body 23 by applying power to the piezoelectric element 24. Thereby, for example, the power receiving device 20 can generate a sound or the power receiving device 20 itself can be vibrated. That is, the power receiving device 20 of the present embodiment also has a sound generation function and a vibrator function. For this reason, by attaching the power receiving device 20 of the present embodiment to, for example, a mobile device such as a mobile phone, a smartphone, a PDA, or an electronic book terminal, a sound generation function or a vibrator function can be given to the mobile device. Therefore, there is no need to separately provide parts for providing a sound generation function and a vibrator function. Therefore, the number of parts of the portable device can be reduced and the size can be reduced.

  Further, unlike the contact-type power transmission system, the non-contact-type power transmission system according to the present embodiment does not require a terminal for power transmission. If the devices are provided with the power receiving device 20 and the power feeding device 10, the power can be widely and generally transmitted by arranging the power receiving device 20 and the power feeding device 10 to be electromagnetically coupled. For this reason, for example, it is possible to freely transmit power from a PDA rich in power to a mobile phone having insufficient power, and to solve the power shortage state.

  In the first embodiment, the example in which the electromagnetic coil 11 is used as a power feeding element and the element including the piezoelectric element 24 and the vibrating body 23 is used as a power receiving element has been described. However, the present invention is not limited to this configuration. The electromagnetic coil 11 may be used as a power receiving element, and an element including the piezoelectric element 24 and the vibrating body 23 may be used as a power feeding element. In that case, electric power is applied to the piezoelectric element 24, and electric power is generated in the electromagnetic coil 11.

  In the first embodiment, the example in which the vibrating body main body 23a and the magnetic member 23c are provided separately has been described. However, the present invention is not limited to this configuration. It is sufficient that at least a part of the vibrating body 23 is formed of a magnetic material. For example, like the power transmission device 2 shown in FIG. 4, the magnetic member 23c may not be provided, and the vibrating body main body 23a may be formed of a magnetic material.

  In the present invention, the magnetic material includes a material that can become a magnetic material by applying electric energy. That is, the magnetic body may be composed of a magnet or the like, but may be composed of a magnetic generator such as an electromagnetic coil.

(Variation of power supply device)
In the said 1st Embodiment, the example using the electric power feeder 10 provided with the electromagnetic coil 11 was demonstrated. However, the power supply apparatus 10 is not limited to this configuration as long as it includes an electric-magnetic conversion element. For example, as shown in FIG. 5, the power feeding device 10 may change the magnetic field by driving an elastic body 32 to which a permanent magnet 31 is attached by a piezoelectric element 33. Specifically, the power feeding device 10 illustrated in FIG. 5 includes an elastic body 32. A piezoelectric element 33 is attached on one main surface of the elastic body 32. Since the configuration of the piezoelectric element 33 is substantially the same as that of the piezoelectric element 24 in the first embodiment, the description of the first embodiment is used and detailed description thereof is omitted here. On the other hand, a permanent magnet 31 is attached on the other main surface of the elastic body 32. By applying a voltage to the piezoelectric element 33, the elastic body 32 and the permanent magnet 31 vibrate together with the piezoelectric element 33. As a result, power transmission is performed.

  In the example illustrated in FIG. 6, the power feeding device 10 includes a disk-shaped member 52 having a central axis C. The disk-shaped member 52 is connected to the actuator 53. With this actuator 53, the disk-like member 52 can rotate around the central axis C. A permanent magnet 51 is attached to the surface of the disk-shaped member 52 on the power receiving device 20 side in an eccentric state. For this reason, when the actuator 53 is driven, the permanent magnet 51 turns around the central axis C. As a result, the magnetic field applied to the power receiving device 20 changes. As a result, power transmission is performed. Further, the permanent magnet 51 may be attached around the central axis C. In this case, if the magnetization direction of the permanent magnet and the direction of the central axis C are arranged to be inclined with respect to each other, the permanent magnet 51 is given to the power receiving device 20. The magnetic field can be changed. Here, if the permanent magnet is attached in a biased manner and the magnetization direction is tilted, if a magnetic field generation source (permanent magnet, electromagnetic coil, etc.) is arranged in the vibration part of the power receiving device 20, Since not only attractive force but also repulsive force can be applied between the permanent magnet 51 and the magnetic field generating source, the force for exciting the vibrating portion of the power receiving device 20 is increased, and the power generation efficiency is further improved.

(Variation of vibration body)
In the first embodiment, the example in which the elastic body 32 is formed in a plate shape has been described. However, in the present invention, the shape of the vibrating body is not particularly limited. Hereinafter, other examples of the vibrating body will be described. In the following description, members having substantially the same functions as those of the first embodiment are referred to by the same reference numerals, and description thereof is omitted.

  FIG. 7 is a schematic side view showing the main part of the power receiving device in the first modification. 8 is a schematic cross-sectional view taken along line VIII-VIII in FIG.

  As shown in FIGS. 7 and 8, the power receiving device 20 of the first modification includes a spiral piezoelectric body 40 having a central axis C. A magnetic member 23c is attached to one end of the spiral piezoelectric body 40, and the other end is attached to the casing. On the outer surface of the spiral piezoelectric body 40, first and second electrodes 25 and 27 are formed. The first and second electrodes 25 and 27 and the helical piezoelectric body 40 constitute a piezoelectric element 24.

  In the present modification, when electric power is applied to the power supply apparatus 10, the magnetic field applied to the magnetic member 23c varies. As a result, the helical piezoelectric body 40 expands and contracts, and electric power is generated by the piezoelectric element 24.

  In this modification, the helical piezoelectric body 40 also has a function as a vibrating body. As described above, the vibrating body may be formed in a spiral shape. The vibrating body may be formed integrally with the piezoelectric body.

  The term “spiral” refers to a shape represented by r = constant or f (z), z = aθ in a cylindrical coordinate system (r, θ, z). Note that f (z) is a function of z. The radius of the spiral piezoelectric body is r. The pitch of the spiral piezoelectric body is 2πa.

  FIG. 9 is a schematic perspective view showing a main part of the power receiving device in the second modification. FIG. 10 is a schematic perspective view in which a part of the power receiving device according to the second modification is enlarged.

  In the second modification, as shown in FIGS. 9 and 10, the power receiving device 20 includes a piezoelectric element 24 formed in a spiral shape. The piezoelectric element 24 is spirally extended from the center toward the tangential direction orthogonal to the radial direction while gradually increasing the diameter. As shown in FIG. 10, the piezoelectric element 24 includes first and second piezoelectric substrates 26 a and 26 b and first to third electrodes 41 to 43. The first piezoelectric substrate 26 a is sandwiched between the first electrode 41 and the second electrode 42. The second piezoelectric substrate 26 b is sandwiched between the second electrode 42 and the third electrode 43. Both the polarization direction of the first piezoelectric substrate 26 a and the polarization direction of the second piezoelectric substrate 26 b are along the radial direction of the piezoelectric element 24. The polarization direction of the first piezoelectric substrate 26a and the polarization direction of the second piezoelectric substrate 26b are opposite to each other.

  As shown in FIG. 9, the central end of the piezoelectric element 24 is connected to the housing 22. On the other hand, the outer end of the piezoelectric element 24 is connected to the magnetic member 23c. For this reason, also in this modified example, in this modified example, the magnetic field applied to the magnetic member 23c varies when electric power is applied to the power supply apparatus 10. As a result, the spiral piezoelectric body 40 vibrates and electric power is generated by the piezoelectric element 24.

  Also in this modification, as in the first modification, the piezoelectric element 24 also has a function as an elastic body. In other words, the elastic body and the piezoelectric element 24 are integrally formed.

  FIG. 11 is a schematic side view illustrating a main part of the power receiving device according to the third modification.

  As shown in FIG. 11, the power receiving device 20 in the third modification includes a plurality of piezoelectric elements 61 a to 61 c that are arranged along the direction H at intervals. The piezoelectric element 61a and the piezoelectric element 61b are connected at the x1 side portion in the direction x, while the piezoelectric element 61b and the piezoelectric element 61c are connected at the x2 side portion in the direction x. For this reason, when viewed from the direction y perpendicular to the direction x and the direction H, the piezoelectric elements 61a to 61c are connected in a crank shape. In the present modification, the magnetic body 23c is attached to the piezoelectric element 61c provided at the position farthest from the housing 22 in the direction H.

  Each of the piezoelectric elements 61a to 61c is a bimorph type piezoelectric element having two piezoelectric substrates 62a and 62b. Although illustration is omitted, each of the piezoelectric elements 61a to 61c has a pair of electrodes for applying a voltage to the piezoelectric substrates 62a and 62b.

  The arrows shown in FIG. 11 indicate the polarization directions of the piezoelectric substrates 62a and 62b. In each of the piezoelectric elements 61a to 61c, the piezoelectric substrate 62a and the piezoelectric substrate 62b are polarized in directions opposite to each other in a direction parallel to the direction H. In addition, the polarization directions of the piezoelectric substrates 62a and 62b are opposite to each other on the x1 side and the x2 side of the direction x. For this reason, when the magnetic force applied to the magnetic body 23c changes and the magnetic body 23c is displaced along the direction H, compressive stress or tensile stress is applied to the piezoelectric substrates 62a and 62b, and power generation is performed.

  Also in this modification, as in the first and second modifications, the piezoelectric element also has a function as an elastic body. In other words, the elastic body and the piezoelectric element are integrally formed. Note that the present invention does not deny power generation that occurs when the vibration of the vibrating body is excited by a disturbance such as vibration or impact applied from the outside.

DESCRIPTION OF SYMBOLS 1, 2 ... Electric power transmission apparatus 10 ... Power feeding apparatus 11 ... Electromagnetic coil 12 ... Detection mechanism 13 ... Control part 20 ... Power receiving apparatus 21 ... Power receiving element 22 ... Case 23 ... Vibrating body 23a ... Vibrating body main body 23a1 ... Vibrating part 23b ... Support part 23c ... Magnetic member 24 ... Piezoelectric element 25 ... First electrode 26, 26a, 26b ... Piezoelectric substrate 27 ... Second electrode 29 ... Control part 31 ... Permanent magnet 32 ... Elastic body 33 ... Piezoelectric element 40 ... Spiral Piezoelectric body 41 ... first electrode 42 ... second electrode 43 ... third electrode 51 ... permanent magnet 52 ... disc-like member 53 ... actuators 61a-61c ... piezoelectric elements 62a, 62b ... piezoelectric substrate

Claims (11)

A power transmission element that constitutes a power transmission device together with an electric-magnetic conversion element,
A vibrating body,
A piezoelectric element mounted on the vibrating body,
The power transmission element, wherein at least a part of the vibrating body is made of a magnetic material.   2. The power transmission element according to claim 1, wherein the power transmission element is a power receiving element that generates electric power in the piezoelectric element when the vibrating body vibrates by electromagnetic energy supplied from the electro-magnetic conversion element.   The power transmission element according to claim 1, wherein the piezoelectric element is a power feeding element that vibrates the vibrating body and supplies electromagnetic energy to the electro-magnetic conversion element.   The vibrating body has first and second main surfaces, the vibrating body main body on which the piezoelectric element is mounted on the first main surface, and the second main surface of the vibrating body main body. The power transmission element according to any one of claims 1 to 3, further comprising: a magnetic member attached on a portion facing the piezoelectric element. A first power transmission element having an electro-magnetic conversion element;
A second power transmission element that transmits power to and from the first power transmission element;
The second power transmission element is:
A vibrating body,
A piezoelectric element mounted on the vibrating body,
At least a part of the vibrating body is made of a magnetic material,
At the time of power transmission, the electro-magnetic conversion element and at least a part made of the magnetic body of the vibrating body are electromagnetically coupled to the electro-magnetic conversion element and at least a part made of the magnetic body of the vibrating body The power transmission device is arranged as follows.   The power transmission device according to claim 5, wherein the electric-magnetic conversion element and the second power transmission element are spaced apart from each other.   The power transmission device according to claim 5, further comprising a control unit that intermittently supplies power to the electro-magnetic conversion element or the piezoelectric element. The control unit intermittently supplies power to the electric-magnetic conversion element,
The control unit supplies power to the electro-magnetic conversion element so that a power supply period to the electro-magnetic conversion element is longer than a reciprocal of a resonance frequency of the first power transmission element. 8. The power transmission device according to 7. A detection unit that detects vibration of the first power transmission element or a generated voltage in the piezoelectric element;
The control unit intermittently supplies power to the electric-magnetic conversion element,
8. The control unit according to claim 7, wherein the control unit adjusts a power supply cycle to the electro-magnetic conversion element so that vibration efficiency of the first power transmission element is improved based on a detection result of the detection unit. Power transmission equipment.   The control unit detects the vibration of the first power transmission element or the generated voltage in the piezoelectric element by the detection unit while changing the period of supplying power to the electro-magnetic conversion element. Detecting a power supply period to the electro-magnetic conversion element that maximizes the amplitude of vibration of one power transmission element or the generated voltage in the piezoelectric element, and power to the electro-magnetic conversion element in the power supply period The power transmission device according to claim 9, wherein supply is performed.   The power transmission device according to claim 7, wherein the control unit vibrates the vibrating body by applying power to the piezoelectric element.

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