JP2003189641A - Power generating equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve power generating performance of a power generating equipment from which an electric power is continuously taken out with a piezoelectric element. <P>SOLUTION: A vibrator system comprising a piezoelectric element is made to generate a free vibration by reversing the direction of a repulsive force based on changes of relative position between magnets, just after a vibration system is applied with a mechanical strain by utilizing a loop of vibration of the vibrator system comprising a piezoelectric element, and the repulsive force between magnets provided to the mechanical system acting around it. Otherwise, by utilizing the loop of vibration at the vibrator system comprising the piezoelectric element and the attractive force between magnets provided to the mechanical system acting around it or the attractive force between a magnet and a soft ferromagnetic body, the vibrator system comprising the piezoelectric element is applied with a mechanical strain, and then the relative position between the magnets or between the magnet and the soft ferromagnetic body is changed to change the attractive force, so that the vibrator system comprising the piezoelectric element is made to generate a free vibration. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power generator using a piezoelectric element, and more particularly to a power generator utilizing a magnetic force acting between ferromagnetic materials and free vibration of the piezoelectric element.

[0002]

2. Description of the Related Art In recent years, various proposals have been made to utilize electric energy by extracting it from mechanical energy by using a piezoelectric phenomenon. When power is generated by the piezoelectric effect, a shock element such as a metal ball or a ceramic ball collides with the piezoelectric element, or one end of the piezoelectric element is fixed and the other end is pressed and deformed. The method of generating electricity by distortion is adopted.

The electric power generated at this time is utilized for the light emission of the light emitting element, or after the secondary battery is charged, it is taken out and utilized. Japanese Unexamined Patent Publication No. 6-209807 discloses an invention in which such a power generator is attached to the sole of a shoe, and the piezoelectric element is deformed to generate electric energy in response to movement such as walking or running to cause the light emitting element to emit light. ing.

Another invention of the same type is disclosed in Japanese Patent Laid-Open No. 11-253.
Japanese Patent Publication No. 071 discloses a lure that incorporates a light emitting diode into a fishing lure and that uses the electromotive force generated by striking a piezoelectric element with an impact body incorporated by the reciprocating motion of the lure to cause the light emitting diode to emit light. There is.

The power generation system using the piezoelectric element according to the above invention is limited to the method of utilizing the energy generated from one impact or bending, and has a problem that the electric energy generated is small.

For continuous power generation, a wind turbine, a water turbine,
If it is possible to generate electric power by generating an impact on a piezoelectric element due to rotational movement of an axle or the like, the field of application will be expanded and useful. As an invention of the same type, Japanese Patent Application No. 54-56872 discloses an invention in which vibration of a contact that vibrates in contact with a gear is transmitted to a piezoelectric element to generate electric power. However, since the flipping of the contactor is used, there is a problem that the impact transmitted to the piezoelectric element is small and the power generation efficiency is poor.

In order to make up for these drawbacks, an invention for continuously generating a high voltage is disclosed in Japanese Patent Laid-Open No. 11-330582.
The publication discloses a power generation device that periodically pressurizes a piezoelectric block body composed of a plurality of piezoelectric bodies by a pressurizing means to continuously take out electric power from the piezoelectric block body.

This conventional example will be described with reference to the drawings. FIG. 8 is a conventional example of a power generation device that continuously takes out electric power from a piezoelectric block body and is illustrated in a partial cross-sectional view. Reference numeral 14 is a rotating body, 12 is a piezoelectric block body, 25 is a pressure receiving plate, 17 is a roller, 16 is a roller supporting member, 15 is a coil spring, and 41 and 42 are output terminals.

In this example, since the piezoelectric element is used to generate electric power, the electric power can be generated semi-permanently. Further, although not shown as a pressurizing means, the repulsive force of the magnet is used to generate noise during the electric power generation. The advantage that it can be reduced is introduced.

[0010]

However, in the method of continuously applying pressure to the piezoelectric element used so far, the free vibration of the piezoelectric element is not always efficiently induced, and the power generation efficiency is There was a problem of being bad.

That is, it is an object of the present invention to improve the power generation performance in a power generation device that uses a piezoelectric element and continuously extracts high voltage power.

[0012]

In order to solve such a problem, the present invention provides a repulsion between vibration antinodes of a vibrator system including a piezoelectric element and magnets arranged in a mechanical system moving around the vibrator. Free vibration is generated in the vibration system including the piezoelectric element by reversing the direction of repulsive force by changing the relative position between the magnets immediately after applying mechanical strain to the vibrator system including the piezoelectric element using force. Or the attraction between the magnets arranged in the vibration antinode of the oscillator system including the piezoelectric element and the mechanical system moving around the oscillator system including the piezoelectric element, or the attraction between the magnet and the soft ferromagnetic material. Mechanical force is applied to the oscillator system including the piezoelectric element by using force, and then the relative position between the magnets or the relative position between the magnet and the soft ferromagnetic material is changed to change the attraction force. To provide a vibrator system including the piezoelectric element. And wherein the generating the derived vibration.

Further, by adjusting the damping time of free vibration and the period for giving the repulsive force between the driven magnets, the generated energy obtained from one mechanical input can be effectively used, and the number of piezoelectric elements can be reduced. There is also.

Further, in this method, since there is no contact between the mechanical input mechanism such as a cam and the piezoelectric element, the piezoelectric element is not worn and the life can be extended.

In other words, in the power generator of the present invention, are magnets arranged both in the antinode of the vibration in the vibrator system including the piezoelectric element and in the mechanical system that moves around the vibration system including the piezoelectric element? Alternatively, the magnet is arranged in either one and the soft ferromagnetic material is arranged in the other.

Further, the piezoelectric element is utilized by utilizing the antinode of the vibration of the vibrator system including the piezoelectric element and the repulsive force of the magnets arranged in the mechanical system moving around the vibration system including the piezoelectric element. Immediately after mechanical strain is applied to the oscillator system that includes it, by changing the relative position between the magnets and reversing the direction of repulsive force, it is possible to generate free vibration in the oscillator system that includes the piezoelectric element. it can.

The antinode of vibration in the oscillator system including the piezoelectric element and the attraction force between the magnets arranged in the mechanical system moving around the oscillator system including the piezoelectric element, or the magnet and the soft ferromagnetic material. A mechanical strain is applied to the oscillator system including the piezoelectric element by using the attraction force of and, and then the relative position between the magnets or between the magnet and the soft ferromagnetic material is changed to change the attraction force. As a result, it is possible to adopt a configuration in which vibration is generated in the vibrator system including the piezoelectric element.

Further, the piezoelectric element may have a bimorph structure or a unimorph structure, one end of which is fixed, and a magnet or a soft ferromagnetic material is arranged at a free end.

The mechanical system moving around the periphery can be a rotary system.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will be given with reference to the drawings.

(Embodiment 1) FIG. 1 is a side view showing a main part of a power generator according to Embodiment 1 of the present invention.
From top to bottom, according to the rotation of the rotation axis ,,,,
The states of and are shown.

In FIG. 1, reference numeral 1 is a piezoelectric bimorph having a structure in which two piezoelectric elements are bonded together, and is fixed by cantilever support. Reference numeral 2 is a rotary shaft, 3a is a permanent magnet disposed on the rotary shaft, and 3b is a permanent magnet attached to the tip of the piezoelectric bimorph on the free end side. The permanent magnets 3a and 3b are arranged so as to repel each other when the rotating shaft rotates and the permanent magnets approach each other.

When the rotating shaft 2 rotates and the permanent magnet 3a arranged on the rotating shaft approaches the permanent magnet 3b attached to the tip of the free end side of the piezoelectric bimorph, the piezoelectric bimorph is gradually repulsed by the repulsive force of the permanent magnet. Will bend to. This is shown in and. As the rotation further proceeds, the piezoelectric bimorph further flexes, and when the repulsive force of the permanent magnet becomes maximum, the amount of flexure of the piezoelectric bimorph becomes maximum.

When the rotation further progresses and goes out of the range of the repulsive force of the permanent magnet 3b attached to the tip of the free end side of the piezoelectric bimorph and the permanent magnet 3a arranged on the rotary shaft, the tip of the piezoelectric bimorph is bent this time. Bounced by repulsive force in the opposite direction. Then, as shown in, the permanent magnets 3a and 3b move in opposite directions.

After being repelled, the piezoelectric bimorph oscillates freely, but the amplitude at this time reaches a maximum immediately after being repelled, and gradually decreases and then stops. The time until the vibration is stopped is determined by the bending amount of the piezoelectric bimorph, the mechanical quality factor Qm, and the load condition. Piezoelectric bimorphs are
Electricity is generated, but as with vibration, an AC-decay type voltage is generated that immediately after being struck, reaches a maximum, then gradually decreases, and then stops.

When the rotation further proceeds, the element is bent again by the repulsive force of the permanent magnet attached to the tip of the free end side of the piezoelectric bimorph and the permanent magnet arranged on the rotating shaft, and electric power is generated. After that, power generation is continuously performed by repeating this.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a side view showing a main part of the power generation device according to the second embodiment of the present invention. From top to bottom, according to the rotation of the rotation axis,
The states of, and are shown. Also, FIG. 1 and FIG.
In, substantially the same members are indicated by common numerals (reference numerals).

In FIG. 2, reference numeral 1 is a piezoelectric bimorph having a structure in which two piezoelectric elements are bonded together, and is fixed by cantilever support. 2 is a rotating shaft, 4 is a permanent magnet arranged on the rotating shaft,
Reference numeral 5 is a soft ferromagnetic material attached to the tip of the piezoelectric bimorph on the free end side. The permanent magnet 4 arranged on the rotary shaft and the soft ferromagnetic material 5 mounted on the free end side tip of the piezoelectric bimorph are arranged so as to attract each other when the rotary shaft rotates and approaches.

When the rotating shaft 2 rotates and the permanent magnet 4 arranged on the rotating shaft approaches the soft ferromagnetic material 5 attached to the tip of the free end side of the piezoelectric bimorph, the piezoelectric bimorph causes the permanent magnet and the soft ferromagnetic material. It will bend as it rotates due to its suction force.

As the rotation further progresses, if the permanent magnet attached to the tip of the free end of the piezoelectric bimorph and the force of attraction of the soft ferromagnetic material arranged on the rotation axis are out of the range of the attraction force, the tip of the piezoelectric bimorph is in the opposite direction to the bent direction. To be played by.

After being repelled, the piezoelectric bimorph oscillates freely, but the amplitude at this time becomes maximum immediately after being repelled, and gradually decreases and then stops. The time until the vibration is stopped is determined by the bending amount of the piezoelectric bimorph, the mechanical quality factor Qm, and the load state. The piezoelectric bimorph generates power during the free vibration, but like the vibration, it generates an AC-decay type voltage that reaches a maximum immediately after being repelled and gradually decreases and then stops.

When the rotation further advances, the element is bent again by the attraction force of the permanent magnet attached to the tip of the free end side of the piezoelectric bimorph and the soft ferromagnetic material arranged on the rotating shaft to generate electricity. After that, power generation is continuously performed by repeating this.

As described above, the piezoelectric bimorph is displaced by utilizing the repulsive force or the attractive force of the permanent magnet or other ferromagnetic material, and the free vibration of the piezoelectric bimorph when the repulsive force is released generates electricity. Thus, it is possible to provide an efficient power generation device that has low torque and produces no noise during power generation.

Needless to say, when a large number of piezoelectric bimorphs are arranged, the power generation becomes large according to the number. Also,
There is a method to attach a plurality of permanent magnets to the rotating shaft for the purpose of increasing the number of power generations per rotation of the rotating shaft and increasing the power generation, but at the stage where the free vibration of the piezoelectric bimorph is not attenuated. If the next permanent magnet approaches and tries to bend the element, the force of free vibration of the piezoelectric bimorph may be canceled by the force that tries to bend the element, which may rather reduce the power generation efficiency. It is important to set the appropriate quantity.

[0035]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is a front view showing a power generator according to the first embodiment of the present invention. In this embodiment, the light emitting diode is turned on by the generated power.

In FIG. 3, reference numeral 6 is a length of 4 formed by laminating two 0.25 mm thick Tokin, piezoelectric element N10 materials to a 0.2 mm thick glass fiber intermediate layer plate.
It is a piezoelectric bimorph with a width of 5 mm, a width of 10 mm, and a thickness of 0.7 mm, and is fixed on three points on the circumference by cantilever support.

At the free end side tip of the piezoelectric bimorph,
The permanent magnet 8b is attached. Reference numeral 7 is a rotary shaft in which two permanent magnets 8a are arranged at a position where the free end side of the piezoelectric bimorph 6 is bent. The permanent magnets 8a and 8b are arranged so as to repel each other. In the present embodiment, the N-poles are arranged so that the N poles face each other when the rotating shaft rotates and the permanent magnets approach each other.

In this embodiment, the tip of the piezoelectric bimorph is displaced by 1 mm each time one of the permanent magnets arranged on the rotating shaft passes. As the piezoelectric element, not only the cantilever-supported bimorph used this time, but also the both-end-supported piezoelectric bimorph, the single-plate piezoelectric element, or the laminated piezoelectric element generate electric energy with mechanical strain. Any one can be applied.

FIG. 4 is a circuit diagram showing an electric circuit according to the first embodiment of the present invention. As a rectifier circuit for the AC voltage generated from the piezoelectric bimorph 6, a switching diode 9
The full-wave rectification circuit is configured by. Numeral 10 is a 22 μF capacitor that smoothes the generated electric energy and is a multilayer ceramic capacitor C55Y5U1E2 manufactured by Tokin.
26Z, 11 is a light emitting diode, Nichia N
It is SPG500S.

When the rotary shaft 7 rotates, the piezoelectric bimorph 6 is repelled to generate power. In this embodiment, a propeller-type wind turbine with a diameter of 200 mm is used as a means for rotating the rotary shaft 7,
Rotation was performed by sending a wind with a wind speed of 3 m.

First, the output of the power generation device of this embodiment when the rectification and smoothing using the electric circuit are not performed, that is, the output of the power generation element will be described. FIG. 5 is a diagram showing a voltage waveform when the piezoelectric bimorph according to the present invention is supported in a cantilever manner, the free end side is displaced by repulsion of a permanent magnet, and this is opened to allow free vibration. The horizontal axis is the time axis,
The generated voltage is shown on the vertical axis. Each time the permanent magnet placed on the rotating shaft passes near the permanent magnet attached to the tip of the free end of the piezoelectric bimorph, a high voltage is generated, and power is generated while gradually attenuating during free vibration. I know that

As shown in FIG. 5, the electric power generated by the vibration of the piezoelectric bimorph is rectified by the full-wave rectifying circuit composed of the switching diode 9 because of the alternating current, and the light emitting diode 11 is caused to emit light. A smoothing capacitor 10 has a role of reducing fluctuations in voltage caused by fluctuations in wind speed. As the means for rotating the rotating shaft, a wind turbine, a water turbine, an axle, or any other rotating member can be used.

In this embodiment, the light emitting diode is turned on by the generated electric power, but it is also effective to use the blinking circuit to cause the light emitting diode to blink to increase the visibility as a light emitting device. Further, not only the light emitting device but also a sounding body such as a buzzer can be sounded.

Further, in order to confirm the power generation performance of the power generator of this example, the following experiment was conducted.

FIG. 6 is a diagram showing a voltage waveform when the piezoelectric bimorph used in this embodiment is supported in a cantilever manner and the push-back of 1 mm is repeated at the free end side to generate power. The horizontal axis is the time axis, and the vertical axis shows the generated voltage. It can be seen from FIG. 6 that the piezoelectric bimorphs have the same displacement amount, but the displacement speed is slow, so the voltage peak is low.

FIG. 7 shows a power generation means utilizing the free vibration of the piezoelectric element according to the present invention, the generated voltage of which is shown in FIG.
Each output is full-wave rectified with respect to the power generation means which shows the generated voltage in FIG.
It is the figure which plotted the charging voltage-time change at the time of charging the capacitor of 00 micro F. It can be seen that when the power generation means according to the present invention is used, the charging voltage rises quickly and the power generation performance is high.

The mechanical systems that move around the oscillator system including the piezoelectric element described in the above embodiments and examples are all rotary systems, but the mechanical system is a general vibration system. Even so, the power generation means utilizing free vibration of the piezoelectric element of the present invention plays a role of increasing power generation efficiency. For example, when the up-and-down motion of the ocean wave is used, it is of course possible to generate electric power by converting it into rotational motion. It is possible to generate electricity using vibration.

[0049]

As described above, according to the present invention, the piezoelectric element such as the piezoelectric bimorph is displaced by the repulsive force or the attractive force of the magnet or other ferromagnetic material, and the piezoelectric force when the repulsive force or the attractive force is released. By generating electric power by utilizing the free vibration of the element, it is possible to provide a power generation device that can efficiently extract electric energy.

[Brief description of drawings]

FIG. 1 is a side view showing a main part of a power generation device according to a first embodiment of the present invention.

FIG. 2 is a side view showing a main part of a power generation device according to a second embodiment of the present invention.

FIG. 3 is a front view showing the power generation device according to the first embodiment of the present invention.

FIG. 4 is a circuit diagram showing an electric circuit according to the first embodiment of the present invention.

5 is a cantilevered support of a piezoelectric bimorph according to the present invention,
The figure which shows the voltage waveform when a free end side is displaced by repulsion of a permanent magnet, this is opened, and it is made to vibrate freely.

6 is a cantilevered support of the piezoelectric bimorph used in Example 1 and repeated pushing back of 1 mm at the free end side,
The figure which shows the voltage waveform when making it generate | occur | produce.

FIG. 7 shows a power generation means utilizing the free vibration of the piezoelectric element according to the present invention, the generated voltage of which is shown in FIG. 5, and a power generation means which is shown in FIG. FIG. 5 is a diagram in which the charging voltage-time change when each output is full-wave rectified and charged in a 100 μF capacitor is plotted.

FIG. 8 is a partial cross-sectional view showing a power generation device that continuously extracts electric power from a piezoelectric block body of a conventional example.

[Explanation of symbols]

1,6 Piezoelectric bimorph 2,7 Rotating shafts 3a, 4,8a Permanent magnets 3b, 8b arranged on the rotating shafts Permanent magnets attached to the free end side tip of the piezoelectric bimorph 5 Soft strength attached to the free end side tip of the piezoelectric bimorph Magnetic substance 9 Switching diode 10 Capacitor 11 Light emitting diode

Claims (5)

[Claims] 1. A magnet is arranged in both of an antinode of vibration in a vibrator system including a piezoelectric element and a mechanical system that moves around the vibration system including the piezoelectric element, or in one of them. And a soft ferromagnet is arranged on the other side. 2. The piezoelectric element is utilized by utilizing the antinode of vibration of a vibrator system including the piezoelectric element and the repulsive force between magnets arranged in a mechanical system that moves around the vibration system including the piezoelectric element. 2. A structure in which free vibration is generated in the vibrating system by reversing the direction of the repulsive force by changing the relative position between magnets immediately after mechanical strain is applied to the vibrating system including the vibrating system. The power generator according to. 3. An antinode of vibration in a vibrator system including a piezoelectric element, and an attraction force between magnets arranged in a mechanical system that moves around the vibrator system including the piezoelectric element, or a magnet and a soft ferromagnetic material. By applying a mechanical strain to the oscillator system including the piezoelectric element by using the attractive force of and, after that, the relative position between the magnets or between the magnet and the soft ferromagnetic material is changed to change the attractive force, The power generation device according to claim 1, wherein the power generation device is configured to generate vibration in a vibrator system including a piezoelectric element. 4. The piezoelectric element has a bimorph structure or a unimorph structure, one end of which is fixed, and a magnet or a soft ferromagnetic material is arranged at a free end of the piezoelectric element. The described power generator. 5. The power generator according to claim 1, wherein the mechanical system that moves in the periphery is a rotary system.