JP2021141723A - Power generation device - Google Patents

Abstract

To provide a vibration power generation device capable of generating power with high efficiency as compared with the prior arts.SOLUTION: A power generation device comprises: a nonmagnetic yoke which has rigidity and elasticity, is constituted of a nonmagnetic material which is long in a first direction, includes a support part in the substantial center thereof, and is vibrated by an external force applied to the support part with both ends across the support part defined as free ends; a magnetostrictive element which is constituted of a magnetostrictive material which is long in the first direction, and fixed near a center of one face among faces of the nonmagnetic yoke bent by the vibration, and receives a stress from the nonmagnetic yoke; a coil wound around the magnetostrictive element in the first direction; two magnets respectively disposed in the vicinity of both the ends of the magnetostrictive element, the two magnets being configured to apply magnetic fields to the magnetostrictive element while being disposed in such a manner that an S pole of one of the two magnets is closer to the magnetostrictive element than an N pole and an N pole of the other magnet is closer to the magnetostrictive element than an S pole; and a magnetic yoke which connects the two magnets in such a manner that a magnetic flux passes between the magnetic poles of the two magnets farther from the magnetostrictive element.SELECTED DRAWING: Figure 1

Description

The present invention relates to a power generation device, and more particularly to a power generation device that generates electric power from vibration using a magnetostrictive material.

In recent years, many usage scenes of the Internet of Things (Internet of Things, hereinafter referred to as IoT) are expected in many fields such as industrial fields, crime prevention / disaster prevention fields, social infrastructure fields, medical / welfare fields, and the like. In IoT, a person and a machine, or a machine and a machine, transmit and receive information such as temperature, humidity, acceleration, or an image acquired by a sensor via a communication network such as the Internet. An important component at that time is a wireless sensor module composed of a sensor, a power supply, and wireless communication.

Currently, many batteries such as a single-use primary battery or a rechargeable secondary battery are used as the power source for the wireless sensor module. When using a primary battery, it is necessary to replace the battery. Further, when a secondary battery is used, charging is required, and wiring and work for charging are required.

As described above, when a battery is used as a power source for the wireless sensor module, regular manual maintenance of the module is required. However, depending on the installation location of the wireless sensor module, such as when the wireless sensor module is embedded in a wall or when it is installed in a narrow gap of a machine, it may be difficult or impossible to replace or charge the battery.

Here, the energy generated in the environment of the installation site, for example, the vibration energy generated from the motor, engine, bridge, etc., the heat energy from the exhaust heat of the plant, the body temperature of the human body, etc., or the environment such as the sun, lighting, etc. If electric power can be generated from light energy from light or the like, the wireless sensor module becomes energetically self-sustaining and can be used for a long period of time without manual maintenance. In addition, since it does not require wiring to the outside, it can be easily added to the already installed infrastructure equipment such as machines, railways, or bridges.

Examples of power generation using energy generated in such an environment include vibration power generation, thermal power generation, and photovoltaic power generation. Among these, vibration power generation is an extremely versatile power generation method that extracts electrical energy from vibration, impact, movement, and the like.

Vibration power generation includes a piezoelectric method, an electrostatic induction method, an electromagnetic induction method, a magnetostrictive method, and the like. Among these, the piezoelectric method using a piezoelectric element (piezo element) has low mechanical durability due to the fragility of the element. In addition, since the electromagnetic induction type power generation unit has a moving part, it is difficult to reduce the size. On the other hand, the magnetostrictive method using an iron-based magnetostrictive material is excellent in workability of the element due to the high ductility of the material, and is useful for application to a wireless sensor module.

In this magnetostrictive vibration power generation, when stress is applied to a magnetostrictive element arranged in a magnetic field, the magnetic flux passing through the magnetostrictive element changes due to the magnetostrictive effect. By arranging a coil around the magnetostrictive element, this change in magnetic flux can be converted into electrical energy by electromagnetic induction.

Patent Document 1 provides a power generation device capable of obtaining a large amount of power generation in a wide frequency band and an electronic device provided with the power generation device in order to efficiently extract power from an environmental vibration phenomenon that occurs widely on a daily basis. do.

FIG. 7 is a diagram showing a configuration example of the power generation device 100 according to Patent Document 1. As shown in FIG. 7, the power generation device 100 includes weights 113 and 123 connected to the yokes 112 and 122, frames 111 fixed to the vibration source 101, magnetostrictive elements 114 and 124, and magnetostrictive elements 114 and 124. The wound magnetic coil 115.125, the yokes 112 and 122, one of which is fixed to the support column 130 and the other of which is connected to the weights 113 and 123, and the yokes 112 and 122 and the magnetostrictive element 114, The first and first are composed of the permanent magnets 116, 117, 126, 127 for the bias magnetic field connected to 124, the support columns 130 fixed to the frame 111, and the power supply circuit connected to the magnetic coils 115, 125. It is composed of the vibration power conversion device of No. 2 and the vibration source 101.

In FIG. 7, when the vibration source 101 vibrates, the vibration propagates to the support column 130 via the frame 111. The vibration of the support column 130 is transmitted to the resonance portion composed of the weight 113, the yoke 112, the magnetostrictive element 114, the magnetic coil 115, and the permanent magnets 116 and 117, and the resonance portion resonates. When the yoke 112 is curved due to resonance, the magnetostrictive element 114 fixed to the yoke 112 expands and contracts by receiving a compression / tensile force. As a result, the magnetostrictive element 114 changes the magnetic flux passing through the magnetostrictive element 114 due to the magnetostrictive effect. The magnetic coil 115 generates an induced electromotive force from this change in magnetic flux by electromagnetic induction (the same applies to the right side of the column in the figure).

Here, the weights 113 and 123 are configured to have different masses, and the resonance frequencies of the resonance portions are different on the left side and the right side of the figure. Therefore, power can be generated in a wider frequency band of the vibration of the vibration source 101.

JP-A-2016-5332

However, in Patent Document 1, the power generation device 100 has a cantilever structure. Therefore, of the magnetostrictive elements 114, the closer to the support column 130, the stronger the stress (compressive force / tensile force) is received. That is, the stress applied to the magnetostrictive element 114 is not uniformly distributed, and the point far from the support column 130 has lower power generation efficiency than the point near the support column 130.

Further, in the power generation device 100 of Patent Document 1, since the frequencies and phases of the powers output from the two vibration power conversion devices are not the same, a loss occurs when they are combined into one output, and power generation occurs. The power generation efficiency of the entire device will decrease. This is a phenomenon that occurs similarly due to individual differences between the magnetostrictive elements 114 and 124, even if the two vibration power converters have the same dimensional configuration.

The present invention solves these problems and provides a power generation device capable of generating power with higher efficiency as compared with the prior art.

The power generation device according to the present invention
It is made of a non-magnetic material that has rigidity and elasticity and is long in the first direction, has a support portion in its substantial center, and vibrates due to an external force applied to the support portion with both ends sandwiching the support portion as free ends. With magnetic yoke
A magnetostrictive element composed of a magnetostrictive material long in the first direction, fixed near the center of one of the surfaces of the non-magnetic yoke curved by vibration, and receiving stress from the non-magnetic yoke.
A coil wound around the magnetostrictive element in the first direction,
Two magnets arranged near both ends of the magnetostrictive element. One of the two magnets has the S pole closer to the magnetostrictive element than the N pole, and the other has the N pole closer to the magnetostrictive element than the S pole. Two magnets that are arranged close to each other and apply a magnetic field to the magnetostrictive element,
A magnetic yoke that connects magnetic fluxes between magnetic poles far from the magnetostrictive elements of two magnets,
To be equipped.

According to the power generation device according to the present invention, it is possible to generate power with higher efficiency as compared with the prior art.

Sectional drawing which shows the structural example of the power generation apparatus 1 in Embodiment 1. Cross-sectional view showing a closed magnetic path in the power generation device 1. A cross-sectional view showing an example of the appearance of the power generation device 1 of FIG. 1 when the vibration source 20 moves downward. A cross-sectional view showing an example of the appearance of the power generation device 1 of FIG. 1 when the vibration source 20 moves upward. The figure which shows the stress distribution at the time of the upward operation in the magnetostrictive element 10 of FIG. A cross-sectional view showing an example of appearance when the vibration source 20 moves downward when the non-magnetic yoke 11 of FIG. 1 is made of a magnetic material. A cross-sectional view showing an example of appearance when the vibration source 20 moves upward when the non-magnetic yoke 11 of FIG. 1 is made of a magnetic material. Sectional drawing which shows the structural example of the power generation apparatus 2 in Embodiment 2. Cross-sectional view showing a configuration example of a power generation device according to Patent Document 1.

The power generation device according to the first aspect of the present disclosure is
It is made of a non-magnetic material that has rigidity and elasticity and is long in the first direction, has a support portion in its substantial center, and vibrates due to an external force applied to the support portion with both ends sandwiching the support portion as free ends. With magnetic yoke
A magnetostrictive element composed of a magnetostrictive material long in the first direction, fixed near the center of one of the surfaces of the non-magnetic yoke curved by vibration, and receiving stress from the non-magnetic yoke.
A coil wound around the magnetostrictive element in the first direction,
Two magnets arranged near both ends of the magnetostrictive element. One of the two magnets has the S pole closer to the magnetostrictive element than the N pole, and the other has the N pole closer to the magnetostrictive element than the S pole. Two magnets that are arranged close to each other and apply a magnetic field to the magnetostrictive element,
A magnetic yoke that connects magnetic fluxes between magnetic poles far from the magnetostrictive elements of two magnets,
To be equipped.

In the power generation device according to the second aspect of the present disclosure, the coil may be composed of a plurality of coils in the first aspect.

The power generation device according to the third aspect of the present disclosure may further include a weight in the vicinity of the free end of the non-magnetic yoke in the first or second aspect.

In the power generation device according to the fourth aspect of the present disclosure, in any one of the first to third aspects, the magnetic yoke may be connected to an external vibration source and an external force may be transmitted to the support portion. ..

The power generation device according to the fifth aspect of the present disclosure is
A first magnetic yoke made of a magnetic material having rigidity and elasticity, which is long in the first direction and is perpendicular to the first magnetic vibrating portion that vibrates by an external force with one end as a free end. A first magnetic support portion that is long in the second direction and whose end is connected to an end portion of the first magnetic vibrating portion that is not a free end, and a first magnetic support portion that is long in the first direction and has a first magnetic support. A first magnetic yoke, including a first magnetic base, connected to an end that is not connected to the first magnetic vibrating portion at both ends of the portion.
A second magnetic yoke made of a magnetic material having rigidity and elasticity, which is long in the first direction, has a second magnetic vibrating portion that vibrates by an external force with one end as a free end, and is long in the second direction. , A second magnetic support portion whose end is connected to an end portion of the second magnetic vibrating portion on the non-free end side, and a second of both ends of the second magnetic support portion which is long in the first direction. A second magnetic yoke, including a second magnetic base, connected to a side end that is not connected to the magnetic vibrating portion of 2.
A non-magnetic support made of a rigid non-magnetic material, long in the second direction, sandwiched and fixed between the first and second magnetic supports, and a non-magnetic support.
It is composed of a magnetostrictive material extending in the first direction centering on the non-magnetic support on the first and second magnetic vibrating parts, and the first and second magnetic vibrating parts and the non-magnetic support. A magnetostrictive element fixed to the body,
The first and second magnets are arranged near the ends fixed to the first and second magnetostrictive parts of the magnetostrictive element, respectively, and one of the S poles is arranged closer to the magnetostrictive element than the N pole. On the other hand, the first and second magnets in which the north pole is arranged closer to the magnetostrictive element than the south pole, and
A coil wound around the magnetostrictive element in the first direction,
To be equipped.

The power generation device according to the sixth aspect of the present disclosure is the fifth aspect described above.
Even if the end of the first magnet far from the magnetostrictive element is connected to the first magnetic base and the end of the second magnet far from the magnetostrictive element is connected to the second magnetic base. good.

In the power generation device according to the seventh aspect of the present disclosure, the coil may be composed of a plurality of coils in the fifth or sixth aspect.

The power generation device according to the eighth aspect of the present disclosure is the first and first in any one of the fifth to seventh aspects, in the vicinity of the free ends of the first and second magnetic vibration portions, respectively. Two weights may be further provided.

The power generation device according to the ninth aspect of the present disclosure has the first magnetic support portion, the second magnetic support portion, and the non-magnetic support portion in any one of the fifth to eighth aspects. At least one of the above may be connected to an external vibration source and transmit an external force to the first and second magnetic vibration parts.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, substantially the same members are designated by the same reference numerals.

[Embodiment 1]
FIG. 1 is a diagram showing a configuration example of the power generation device 1 according to the first embodiment. In FIG. 1, the power generation device 1 includes a non-magnetic yoke 11, weights 14 and 15, a magnetostrictive element 10, coils 12 and 13, magnets 18 and 19, magnets 18 and 19, and a magnetic yoke 17. ..

In FIG. 1, the non-magnetic yoke 11 has a plate-shaped portion that is long in the x-axis direction in the figure and thin in the z-axis direction, and a plate-shaped portion that is fixed near the center of the non-magnetic yoke 11 in the z-axis direction and thin in the x-axis direction. It has a combined T-shape. Of the two plate-shaped portions, the former is referred to as a vibrating portion 21 and the latter is referred to as a support portion 16. The non-magnetic yoke 11 is made of a material having rigidity and elasticity, and vibrates in the z-axis direction by an external force transmitted through the support portion 16. The weights 14 and 15 are fixed in the vicinity of both ends of the vibrating portion 21, respectively, and the vibration of the vibrating portion 21 is sustained for a long time.

In the present embodiment, the term "fixing" refers to a state in which two components are bonded with an epoxy adhesive, but the fixing means is not limited to the adhesive, and is mechanically fixed by, for example, a bolt or the like. May be good. However, if the fixing means is made of a magnetic material, magnetic flux may leak and the power generation efficiency may decrease. Therefore, it is preferable to use a non-magnetic material for the fixing means.

The magnetostrictive element 10 is made of a magnetostrictive material that is long in the x-axis direction and thin in the z-axis direction, and is fixed to the upper surface (the surface in the positive direction of the z-axis) of the non-magnetic yoke 11. Hereinafter, in correspondence with the drawing, the positive direction of the z-axis may be referred to as "up", the negative direction may be referred to as "down", the positive direction of the x-axis may be referred to as "right", and the negative direction may be referred to as "left" ("vertical"). , The same applies to "horizontal").

The coils 12 and 13 are wound around the magnetostrictive element 10 in the x-axis direction, the coil 12 is arranged on the right side of the support portion 16, and the coil 13 is arranged on the left side of the support portion 16. The coils 12 and 13 generate an induced electromotive force due to a change in the magnetic flux passing through the magnetostrictive element 10. The magnetic yoke 17 is made of a magnetic material long in the x-axis direction and is fixed to the support portion 16 of the non-magnetic yoke 11. The magnetic yoke 17 is also fixed to the vibration source 20, and the external force from the vibration source 20 is transmitted to the vibration portion 21 via the support portion 16 of the magnetic yoke 17 and the non-magnetic yoke 11. The magnets 18 and 19 are fixed in the vicinity of both ends of the magnetic yoke 17. The magnet 18 is arranged on the right side of the support portion 16 so that the north pole is closer to the right end of the magnetostrictive element 10 than the south pole. The magnet 19 is arranged on the left side of the support portion 16 so that the S pole is closer to the left end of the magnetostrictive element 10 than the N pole.

FIG. 2 is a cross-sectional view showing a closed magnetic path in the power generation device 1 of FIG. However, in FIG. 2, the coils 12 and 13 are omitted for the sake of simplicity.

As shown in FIG. 2, in the above configuration, the magnetostrictive element 10, the magnet 19, the magnetic yoke 17, and the magnet 18 form a closed magnetic path. That is, the magnetic flux emitted from the north pole of the magnet 18 enters the south pole of the magnet 19 through the magnetostrictive element 10, and the magnetic flux emitted from the north pole of the magnet 19 passes through the magnetic yoke 17 to the south pole of the magnet 18. come in. As a result, the magnetic flux leaking to the other parts of the power generation device 1 and the outside of the power generation device 1 is reduced, and a stable magnetic field is applied to the magnetostrictive element 10.

Returning to FIG. 1, the vibration source 20 is connected to the outside of the power generation device 1, and transmits the external physical movement to the magnetic yoke 17 and the support portion 16 of the power generation device 1 as an external force. When the vibrating portion 21 of the non-magnetic yoke 11 vibrates due to this external force, the vibrating portion 21 is curved, so that the magnetostrictive element 10 fixed to the upper surface of the vibrating portion 21 receives a compressive force or a tensile force from the vibrating portion 21. When the magnetostrictive element 10 receives a compressive force or a tensile force, the magnetic flux passing through the magnetostrictive element 10 changes due to the magnetostrictive effect, and an induced electromotive force is generated in the coils 12 and 13 due to the change in the magnetic flux.

Details of the above components of the power generation device 1 will be described below.

<Magnetorstrictive element 10>
The magnetostrictive element 10 is made of a magnetic material having a long shape in the x-axis direction in the figure, and is fixed to the non-magnetic yoke 11. The type of magnetic material is not particularly limited, but it is desirable to use a material having ductility because it expands / contracts by receiving an external force. For example, an iron-gallium-based alloy, an iron-cobalt-based alloy, or the like can be used.

In the present embodiment, the shape of the magnetostrictive element 10 is a rectangular parallelepiped having a width of 16 mm, a thickness of 1 mm, and a length of 30 mm. However, the shape of the magnetostrictive element 10 is not limited to this, and the dimensions in the y-axis and z-axis directions are smaller than the inner diameters of the coils 12 and 13, and the dimensions in the x-axis direction are longer than the coils 12 and 13, for example, a rectangular parallelepiped. , Cube, cylinder, polygonal pillar, etc. may be used.

<Coil 12, 13>
The coils 12 and 13 are wound with a space around the magnetostrictive element 10, and an induced electromotive force is generated by a change in the magnetic flux passing through the magnetostrictive element 10. The materials of the coils 12 and 13 are not particularly limited, but may be, for example, copper wire or aluminum wire. Further, the magnitude of the generated voltage can be adjusted by adjusting the number of turns of the coils 12 and 13.

In the present embodiment, the power generation device 1 includes two coils 12 and 13, but may include three or more coils, or may include only one coil in which the coils 12 and 13 are integrated. good.

<Magnets 18, 19>
The magnets 18 and 19 are fixedly arranged on the magnetic yoke 17 with a space provided between the magnets 18 and 19 and the non-magnetic yoke 11 facing each other. In the present embodiment, the magnet 18 is arranged so that the north pole is on the upper surface and the magnet 19 is arranged so that the south pole is on the upper surface. As a result, the magnets 18 and 19, the magnetic yoke 17, and the magnetostrictive element 10 form a closed magnetic path. That is, the magnetic flux emitted from the north pole of the magnet 18 enters the south pole of the magnet 19 through the magnetostrictive element 10, and the magnetic flux emitted from the north pole of the magnet 19 passes through the magnetic yoke 17 to the south pole of the magnet 18. come in.

Here, the magnets 18 and 19 may be arranged so as to form the above-mentioned closed magnetic path, and therefore the relationship between the two magnetic poles may be reversed. That is, the upper surface of the magnet 18 may be the south pole, and the upper surface of the magnet 19 may be the north pole. In that case, the directions of the magnetic fluxes in the closed magnetic path are opposite, the magnetic flux emitted from the north pole of the magnet 19 enters the south pole of the magnet 18 through the magnetic strain element 10, and the magnetic flux emitted from the north pole of the magnet 18 is It passes through the magnetic yoke 17 and enters the S pole of the magnet 19.

In the present embodiment, the materials of the magnets 18 and 19 are neodymium magnets, but the magnets 18 and 19 are not limited to this, and may be, for example, a ferrite magnet, a cobalt magnet, or the like.

<Non-magnetic yoke 11>
The non-magnetic yoke 11 is made of a non-magnetic material having elasticity and rigidity or a material having low magnetic permeability, and has a T-shape having a support portion in the center. The reason why the non-magnetic yoke 11 is made of a non-magnetic material will be described later.

The non-magnetic yoke 11 has a T-shape in the present embodiment, but the vibrating portion 21 is not limited to a flat surface, and is, for example, a V-shape, an inverted V-shape, or a U-shape. Alternatively, the shape may be curved in an inverted U shape.

<Magnetic yoke 17>
The magnetic yoke 17 is made of a magnetic material having a high magnetic permeability, has a plate-like shape, and is fixed to the vibration source 20.

<Weights 14, 15>
The weights 14 and 15 are made of a non-magnetic material or a material having a low magnetic permeability. The weights 14 and 15 are fixed to both free ends of the vibrating portion 21 of the non-magnetic yoke 11. In the present embodiment, the weights 14 and 15 have a shape in which a plurality of disk-shaped weights are stacked, but the weights 14 and 15 may have any shape as long as they have a sufficient mass to sustain vibration. .. For example, it may be a rectangular parallelepiped, a hemisphere, or the like.

The detailed operation of the power generation device 1 configured as described above will be described.

FIG. 3A is a cross-sectional view showing an operation example when the vibration source 20 moves downward in the power generation device 1 of FIG. FIG. 3B is a diagram showing an operation example when the vibration source 20 moves upward.

In FIG. 3A, when the vibration source 20 moves downward, its external force is transmitted to the vibrating portion 21 of the magnetic yoke 11 via the magnetic yoke 17 and the support portion 16 of the non-magnetic yoke 11. Since the weights 14 and 15 have a larger mass than the vibrating portion 21, the downward movement is delayed due to inertia. As a result, the vibrating portion 21 of the magnetic yoke 11 is curved in a U shape as shown in FIG. 3A. Here, since the magnetostrictive element 10 is fixed to the upper surface of the vibrating portion 21, it receives a compressive force from the vibrating portion 21 curved in a U shape.

When the magnetostrictive element 10 receives a compressive force, it changes the magnetic flux density of the magnetic flux passing through the inside in a direction of increasing the magnetic flux density. Due to this change in magnetic flux, an induced electromotive force is generated in the coils 12 and 13 (not shown), so that power generation is achieved. The white arrow in FIG. 3A indicates the direction of the physical operation of the vibration source 20, and the thin arrow indicates the direction of the change in the magnetic flux generated by the magnetostrictive element 10 (the same applies to FIG. 3B).

On the contrary, when the vibration source 20 moves downward as shown in FIG. 3B, the vibrating portion 21 of the magnetic yoke 11 is curved in an inverted U shape, and the magnetostrictive element 10 receives a tensile force. When the magnetostrictive element 10 receives a tensile force, the magnetostrictive element 10 changes in a direction of lowering the magnetic flux density of the magnetic flux passing through the inside. Due to this change in magnetic flux, induced electromotive force is generated in the coils 12 and 13, and power generation is achieved.

The vibrating unit 21 that receives the external force resonates at a resonance frequency based on the elasticity of the vibrating unit 21 and the masses of the weights 14 and 15, and alternately repeats U-shaped and inverted U-shaped bending. As a result, an AC voltage is generated in the coils 12 and 13.

FIG. 4 is a top view showing the stress distribution during upward operation of the magnetostrictive element 10 of FIG. FIG. 4 shows a stress distribution when the vibration source 20 is vibrated at an acceleration of 0.05 G and a frequency of 5 Hz.

According to the principle of the lever, the magnetostrictive element 10 receives a larger stress at a position closer to the central support portion 16. Since the magnetostrictive elements 10 are arranged on both sides across the center of the vibrating portion 21 of the non-magnetic yoke 11, a power generation device having a vibrating portion having a cantilever structure according to the prior art (for example, FIG. 7 (Patent Document 1)). The distance from the fulcrum at the position farthest from the fulcrum (support portion 16, column 130) of the vibrating portion is smaller than that of the magnetostrictive element in the power generation device 100). As described above, the magnetostrictive element receives a larger stress at a position closer to the fulcrum of the vibrating portion, and the generated magnetic flux change also becomes larger. Therefore, as shown in FIG. 4, since the magnetostrictive element 10 is subjected to a stress closer to a uniform distribution and larger than that of the prior art, the power generation efficiency of the power generation device is also increased.

Further, since the closed magnetic path included in the power generation device 1 is only one closed magnetic path including the magnets 18 and 19, the magnetostrictive element 10 and the magnetic yoke 17, the magnetic flux that generates the induced electromotive force in the two coils 12 and 13 is It is substantially the same. Therefore, the phases of the electromotive forces from the two coils 12 and 13 match, and no loss occurs when they are combined.

Here, suppose that instead of the non-magnetic yoke 11, a magnetic material having the same shape is used. 5A and 5B are cross-sectional views showing the magnetic flux during operation in the vertical direction when the non-magnetic yoke 11 of FIG. 1 is made of a magnetic material, and correspond to FIGS. 3A and 3B, respectively.

In this configuration, when the vibration source 20 operates upward, the two closed magnetic paths shown in FIG. 5A are formed. As shown in FIG. 5A, the two closed magnetic paths overlap each other in the support portion 16 of the yoke in opposite directions. A closed magnetic path is formed in the direction in which the two magnetic fluxes cancel each other out (the same applies to FIG. 5B). Therefore, the non-magnetic yoke 11 is preferably made of a non-magnetic material or a material having a low magnetic permeability.

As described above, the magnetostrictive element 10 is closer to a uniform distribution and receives a larger stress than the magnetostrictive element fixed to the vibrating portion of the cantilever structure in the power generation device according to the prior art. The change in magnetic flux generated by the element 10 also becomes large. Further, since there is no phase difference between the induced electromotive forces generated in the plurality of coils 12 and 13, the loss when synthesizing them is reduced. As a result, the power generation efficiency of the magnetostrictive element 10 is improved.

[Embodiment 2]
FIG. 6 is a cross-sectional view showing a configuration example of the power generation device 2 according to the embodiment. In FIG. 6, the power generation device 2 differs from the power generation device 1 in FIG. 1 in the following points. That is, instead of the non-magnetic yoke 11 and the magnetic yoke 17, the magnetic yokes 31 and 32 and the non-magnetic support 33 are provided.

In FIG. 6, the magnetic yokes 31 and 32 are each made of, for example, a magnetic material having a U-shape in which three rectangular plates are combined. Of these three plate portions, the lower portion in the figure is referred to as a base portion 313, 323, the central portion is referred to as a support portion 312, 322, and the upper portion is referred to as a vibrating portion 311, 321. Similar to the support portion 16 in FIG. 1, the non-magnetic support 33 is made of a plate-shaped non-magnetic material long in the z-axis direction, and is sandwiched and fixed between the support portion 312 and the support portion 322.

One ends of the base portions 313 and 323 are connected to the lower ends of the support portions 321 and 322, respectively, and are fixed to the vibration source 20 so as to be in contact with the lower ends of the non-magnetic support 33.

As described above, the support portions 312 and 322 are fixed to the non-magnetic support 33 so as to sandwich the non-magnetic support 33. The set of the support portions 312 and 322 fixed to each other and the non-magnetic support 33 constitutes the support portion 36. The support portion 36 transmits the external force from the vibration source 20 to the vibrating portion in the same manner that the support portion 16 in FIG. 1 transmits the external force to the vibrating portion 21.

The vibrating portions 311, 321 are fixed so that one ends thereof are connected to the upper ends of the support portions 312 and 322, respectively, and are in contact with the upper ends of the non-magnetic support 33. Of both ends of the vibrating portions 311, 321, the other ends that are not fixed to the supporting portions 312 and 322 are free ends, and weights 14 and 15 are fixed in the vicinity thereof as in the vibrating portion of FIG. .. The set of vibrating portions 311, 321 fixed to each other at one end vibrates by an external force, and stress is applied to the magnetostrictive element 10 in the same manner as the vibrating portion 21 of FIG.

In the power generation device 2 configured as described above, two closed magnetic paths are formed as described above with reference to FIGS. 5A and 5B when the non-magnetic yoke 11 is made of a magnetic material. Here, the support portion 36 is configured with a non-magnetic support 33 made of a non-magnetic material sandwiched in the center. Therefore, the two closed magnetic paths are a closed magnetic path formed by the magnetic yoke 31 and the magnet 18, and a closed magnetic path composed of the magnetic yoke 32 and the magnet 19. That is, since the two closed magnetic paths do not overlap each other and the magnetic fluxes do not cancel each other out, the same effect as that of the power generation device 1 of FIG. 1 can be obtained.

However, the change in physical characteristics due to the vibrating portions 311, 321 made of magnetic material being attracted to the magnets 18 and 19, or the free end side of the vibrating portions 311, 321 that does not form a closed magnetic path. Attention must be paid to changes in magnetic characteristics due to leakage of magnetic flux to the portion. Further, in the present embodiment, the magnetic yokes 31 and 32 are configured as magnetic yokes 31 and 32 in which three plate-shaped magnetic materials are combined and integrated, but these are not integrated. good. That is, instead of the magnetic yokes 31 and 32, a magnetic vibrating portion, a magnetic support portion, and a magnetic base portion made of a plate-shaped magnetic material may be configured as individual elements having appropriately fixed ends. ..

Further, the support portion and the base portion of the magnetic yoke 31 do not necessarily have to be fixed to the non-magnetic support 33 and the vibration source 20, respectively, so that the magnetic flux passes between the vibrating portion of the magnetic yoke 31 and the magnet 18. It may have any shape as long as it is connected to. For example, it may be a magnetic material or the like that linearly connects the left end of the vibrating portion of the magnetic yoke 31 and the lower end of the magnet 18 (the same applies to the magnetic yoke 32 and the magnet 19). However, in order to ensure the symmetry of vibration, it is preferable that the configurations of the magnetic yokes 31 and 32 are substantially the same.

As described above, the magnetostrictive element 10 is closer to a uniform distribution and receives a larger stress than the magnetostrictive element fixed to the vibrating portion of the cantilever structure in the power generation device according to the prior art. The change in magnetic flux generated by the element 10 also becomes large. Further, since there is no phase difference between the induced electromotive forces generated in the plurality of coils 12 and 13, the loss when synthesizing them is reduced. As a result, the power generation efficiency of the magnetostrictive element 10 is improved.

The power generation device according to the present invention can improve the power generation efficiency. The power generation device of the present invention for the wireless sensor module, which is an important component of IoT, which is expected to be used in many fields such as industrial fields, crime prevention / disaster prevention fields, social infrastructure fields, medical / welfare fields, etc. The application of is particularly useful.

1 Power generator 6 Magnetostrictive element 11 Magnetostrictive element 11 Non-magnetic yoke 12, 13 Coil 14, 15 Weight 16 Support 17 Magnetic yoke 18, 19 Magnet 20 Vibrating body 21 Vibrating unit 31, 32 Magnetic yoke 311, 321 Vibrating unit 312, 322 Supports 313,323 Base 33 Non-magnetic support

Claims (9)

It is made of a non-magnetic material that has rigidity and elasticity and is long in the first direction, has a support portion in its substantial center, and vibrates due to an external force applied to the support portion with both ends sandwiching the support portion as free ends. With a non-magnetic yoke
A magnetostrictive element composed of a magnetostrictive material long in the first direction, fixed near the center of one of the surfaces of the non-magnetic yoke curved by vibration, and receiving stress from the non-magnetic yoke.
A coil wound around the magnetostrictive element in the first direction,
Two magnets arranged in the vicinity of both ends of the magnetostrictive element, one of the two magnets having an S pole closer to the magnetostrictive element than the N pole, and the other having an N pole closer to the S pole than the S pole. Two magnets that are arranged close to the magnetostrictive element and apply a magnetic field to the magnetostrictive element,
A magnetic yoke that connects the two magnets so that magnetic flux passes between the magnetic poles far from the magnetostrictive element.
A power generator equipped with. The power generation device according to claim 1, wherein the coil is composed of a plurality of coils. The power generation device according to claim 1 or 2, further comprising a weight in the vicinity of the free end of the non-magnetic yoke. The power generation device according to any one of claims 1 to 3, wherein the magnetic yoke is connected to an external vibration source and transmits the external force to the support portion. A first magnetic yoke made of a magnetic material having rigidity and elasticity, which is long in the first direction and vibrates by an external force with one end as a free end, and a first magnetic vibrating portion in the first direction. The first magnetic support portion, which is long in the vertical second direction and whose end is connected to the end of the first magnetic vibrating portion on the non-free end side, and the first magnetic support portion, which is long in the first direction, said. A first magnetic yoke including a first magnetic base portion connected to an end portion of both ends of the first magnetic support portion that is not connected to the first magnetic vibrating portion.
A second magnetic yoke made of a magnetic material having rigidity and elasticity, which is long in the first direction and vibrates by an external force with one end as a free end, and the second direction. A second magnetic support portion whose end is connected to an end portion of the second magnetic vibrating portion on the non-free end side, and a second magnetic support portion which is long in the first direction and is long in the first direction. A second magnetic yoke, including a second magnetic base, which is connected to the end of both ends that is not connected to the second magnetic vibrating portion.
A non-magnetic support made of a rigid non-magnetic material, long in the second direction, sandwiched and fixed between the first and second magnetic supports, and a non-magnetic support.
The first and second magnetic vibrating portions, which are composed of a magnetostrictive material extending in the first direction centering on the non-magnetic support on the first and second magnetic vibrating portions, And the magnetostrictive element fixed to the non-magnetic support,
The first and second magnets arranged in the vicinity of the ends fixed to the first and second magnetic vibrating portions of the magnetostrictive element, one of which has an S pole rather than an N pole. The first and second magnets, the other of which is located closer to the magnetostrictive element, with the north pole closer to the magnetostrictive element than the south pole.
A coil wound around the magnetostrictive element in the first direction,
A power generator equipped with. The end of the first magnet far from the magnetostrictive element is connected to the first magnetic base, and the end of the second magnet far from the magnetostrictive element is the second magnetic. Connected to the base,
The power generation device according to claim 5. The power generation device according to claim 5 or 6, wherein the coil is composed of a plurality of coils. The power generation device according to any one of claims 5 to 7, further comprising first and second weights in the vicinity of the free ends of the first and second magnetic vibration portions, respectively. At least one of the first magnetic support, the second magnetic support, and the non-magnetic support is connected to an external vibration source, and an external force is applied to the first and second magnetic vibration parts. The power generation device according to any one of claims 5 to 8 to be transmitted.

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