JPH0465173A - Generator using ultrasonic vibration - Google Patents

Abstract

PURPOSE:To generate a piezoelectric element without contact by applying vibration of a vibrating member to the element as ultrasonic vibration of gas existing between the elements. CONSTITUTION:When vibration is applied to a piezoelectric element 40 to generate a voltage, an ultrasonic vibration generator 20 is first used, and its vibrating member 24 is vibrated in an ultrasonic frequency band. Thus, a second diaphragm 36 opposed to the pressure receiving surface 40a of the element 40 is vibrated by the vibration of the member 24 through a first diaphragm 34 and fluid 38, the vibration becoming ultrasonic vibration of gas existing between the elements 40 is applied to the element 40, the element 40 is electrically polarized by a positive piezoelectric effect to generate a voltage. The generated voltage is output from leads 44 through electrodes provided on both side surfaces of the element 40. Accordingly, a pressure is applied to the element 40 without contact to generate the voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a power generation device using a piezoelectric element, and more particularly to a power generation device that uses ultrasonic vibration to cause the piezoelectric element to generate electricity in a non-contact manner.

[Prior Art] Power generation devices that use piezoelectric elements to generate electricity have been known, and this type of power generation device is used for cases where the voltage output from the piezoelectric elements is used as a drive source for micromachines, and for other purposes. It is used for various purposes.

FIG. 5 shows the basic configuration of a conventional power generation device using piezoelectric elements.

This power generation device includes a piezoelectric element 12 fixedly mounted on a fixed plate 10, and a pressurizer 16 that applies compressive force to the piezoelectric element 12 via a pressure member 14, and outputs an output from the piezoelectric element 12. The voltage is applied to the electrodes 12a provided on both sides of the electrodes 12a.
, 12b are connected to lead wires 18a, 18b.

Such a piezoelectric power generation device is formed based on the principle that a voltage is generated when compressive force is applied to the piezoelectric element 12 and when the compressive force is released. The output voltage V of this device is generally expressed by the following formula (%) where g: Piezoelectric output constant F: Pressure force t: Thickness of the element S: Cross-sectional area of the element.

In piezoelectric power generators, stress (F
/S), it is possible to generate a high voltage of several 100 KV, and by adjusting the pressurizing speed (or pressurizing force release speed), it is possible to generate a high voltage of several 100 KV.
It is possible to generate signals with various voltage waveforms having a rise time of 0m5.

Next, the operation of this power generation device will be explained.

When applying pressure to the piezoelectric element 12 to generate a voltage, the pressurizer 16 is driven, the pressure member 14 is lowered, and the piezoelectric element 12 is compressed. This compressive force generates a voltage in the piezoelectric element 12, and this voltage is taken out via the lead wires 18a, 18b.

Further, the pressure from the piezoelectric element 12 is released by raising the pressure member 14 using the pressurizer 16.

[Problems to be Solved by the Invention] However, this conventional power generation device is configured to apply pressure by bringing the pressure member 14 into direct contact with the piezoelectric element 12.

Therefore, there was a problem in that the piezoelectric element 12 had to be fixed on the fixing plate 10 with strength enough to withstand the pressure.

For example, when the piezoelectric element 12 is used as a drive source for a micromachine, the structure is such that the piezoelectric element 12 is integrated with the micromachine. Under this structure, when a pressure force is applied to the piezoelectric element 12 using the pressure member 14, there is a problem that the pressure force is not interrupted and the micromachine is destroyed.

Furthermore, in the case of a moving micromachine, it is necessary to form the piezoelectric element 12 separately from the pressure member 14, so the length of the lead wires 14g and 14b should be at least as long as the moving distance. There must be. For this reason, lead wire 1
There was a problem in that a voltage drop occurred within 8a and 18b, and the generated voltage itself could not be taken out.

[Purpose of the Invention] The present invention has been made in view of such conventional problems, and its purpose is to provide a power generation device using ultrasonic vibration that can generate power without contacting a piezoelectric element. It is in.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides: an ultrasonic vibration generating means including a piezoelectric element and a vibrating member that vibrates in the ultrasonic frequency range; a vibration transmission means for transmitting vibration to the piezoelectric element, the vibration transmission means is filled with a high-density fluid for a vibration transmission medium, and has openings at both ends thereof closed with a diaphragm to transmit vibrations of a predetermined length. A transmission hollow member is provided, one diaphragm of which is fixed to the vibrating member, and the other diaphragm is formed to face the pressure receiving surface of the piezoelectric element with a predetermined distance therebetween, and transmits the vibration of the vibrating member to the piezoelectric element. The piezoelectric element is characterized in that it is applied to the piezoelectric element as an ultrasonic vibration of the gas existing between the piezoelectric element and the piezoelectric element to generate electricity in a non-contact manner.

Here, it is preferable to use mercury as the high-density fluid for the vibration transmission medium.

In this case, the vibration transmitting hollow member and the two diaphragms provided at both ends thereof are preferably formed using a material having mercury resistance.

Further, it is preferable that the vibration transmission means is formed as a flexible cable so that its vibration transmission path can be arbitrarily set.

Below, the power generation device using ultrasonic vibration of the present invention will be explained in more detail.

FIG. 1 shows the basic configuration of a power generation device according to the present invention.

The power generation device of the present invention includes an ultrasonic vibration generator 20 having a vibrating member 24 that vibrates in an ultrasonic frequency range, and a vibration transmitting section 30 that transmits the generated ultrasonic vibrations. is transmitted to the piezoelectric element 40 in a non-contact manner, and the piezoelectric element 40 is configured to generate a voltage.

The vibration generator 20 includes a vibration member 24 inside the casing 22.
is arranged, and the vibrating member 24 is vibrated in the ultrasonic frequency range using the actuator 26.

The vibration transmission section 30 has a cylindrical hollow member 32 for vibration transmission having a predetermined length, and a first diaphragm 34 and a second diaphragm 36 are fixed around the openings at both ends of the hollow member 32. has been done. A high-density fluid 38 is sealed within the hollow member 32 as a vibration transmission medium.

One end of the vibration transmitting hollow member 32 is fixedly attached to the casing 22, and a first diaphragm 34 provided with an opening at one end is further fixed to the vibrating member 24. In addition, this hollow member 32 has a second diaphragm 36 provided on the other end opening side that connects the piezoelectric element 4.
It is arranged so as to face the pressure receiving surface 40a of No. 0 with a predetermined distance therebetween.

The piezoelectric element 40 also includes a soft member 5 made of an insulating material.
0, and lead wires 44 are connected to electrodes provided on both sides thereof.

[Function] The present invention consists of the above-mentioned structure, and its function will be explained next. When applying vibration to the piezoelectric element 40 to generate voltage, first, the ultrasonic vibration generator 20 is used to cause the vibrating member 24 to vibrate in the ultrasonic frequency range.

Thereby, the vibration of the vibrating member 24 is transmitted to the pressure receiving surface 4 of the piezoelectric element 40 via the first diaphragm 34 and the fluid 38.
The second diaphragm 36 facing 0a is vibrated.

The vibration of the second diaphragm 36 becomes an ultrasonic vibration of the gas existing between the piezoelectric element 40 and is applied to the piezoelectric element 40, and the piezoelectric element 40 has electrical polarization due to the positive piezoelectric effect. occurs, and a voltage is generated. The generated voltage is applied to electrodes (not shown) provided on both sides of the piezoelectric element 4o.
It is taken out from the lead wire 44 via.

As described above, according to the present invention, the ultrasonic vibrations generated by the ultrasonic vibration generator 20 are transmitted to the piezoelectric element 40 as gas ultrasonic vibrations via the vibration member 24 and the vibration transmission section 30, and the piezoelectric element 4o is vibrated to generate voltage.

Therefore, according to the present invention, pressure can be applied to the piezoelectric element 4o in a non-contact manner compared to the conventional power generation device using a piezoelectric element shown in FIG.
In FIG. 1, the soft member 50) is not required to have great strength as in the conventional case.

Therefore, for example, a piezoelectric element 40 attached to a micromachine
Even when transmitting ultrasonic vibrations to generate voltage, a large pressurizing force is not applied to the micromachine and destroys it.

In addition, by forming the vibration transmission section 30 as a flexible hollow cable for vibration transmission, the vibration transmission path can be freely set, so that even when the piezoelectric element 40 moves, the vibration transmission path can be freely set. , the vibration transmission path can be changed in accordance with this movement, and a voltage can be generated in the piezoelectric element 40.

[Effects of the Invention] As explained above, according to the present invention, ultrasonic vibrations are applied to the piezoelectric element as vibrations of gas such as air through a vibration transmission means, and the power generation element is vibrated, thereby generating piezoelectric energy. This has the effect of allowing the element to generate electricity without contact. In particular, according to the present invention, since mechanical pressure is not directly applied to the piezoelectric element, the mounting of the piezoelectric element does not require large mechanical strength on the part side as in the past, and This is extremely suitable when the element is used as a drive source for a micromachine.

Furthermore, according to the present invention, by forming the vibration transmission means as a flexible cable, the vibration transmission path to the piezoelectric element can be freely selected and set;
This has the advantage that voltage can be generated even when the piezoelectric element moves.

Therefore, even if the micromachine is moved, the piezoelectric element can be attached to the micromachine, and the length of the lead wires connecting the piezoelectric element and each circuit within the micromachine can be made sufficiently short to reduce the voltage drop that occurs. There is also the effect that it can be prevented.

[Example] Next, a preferred example of the present invention will be described in detail with reference to FIGS. 1 and 2.

The power generation device of the present invention uses the actuator 26 of the ultrasonic vibration generator 20 to cause the vibration member 24 to ultrasonically vibrate in the ultrasonic frequency range, and converts this vibration into air vibration via the vibration transmission section 30 to the pressure element 40. is applied to.

The vibration transmitting unit 30 is formed as a cable that transmits vibrations, and specifically, a stainless steel hollow pipe of a predetermined length is used as the hollow member 32, and its outer diameter is 10 cm.
The thickness is 0.2 mm. A stainless steel flat diaphragm with a thickness of 0.05 mm is attached to the first and second diaphragms 34 on both end faces of this pipe.
, 36 are fixed at the periphery.

One end of the stainless steel pipe formed as the hollow member 32 is fixed to the casing 22 of the ultrasonic vibration generator 20. Further, the free end of the vibrating member 24 is fixed to the center of the first diaphragm 34 . Further, the second diaphragm 36 faces the pressure receiving surface 40a of the piezoelectric element 40 at a predetermined interval. Furthermore, mercury is sealed as the high-density fluid 22 in the hollow portion of the hollow member 32 .

Moreover, the piezoelectric element 40 of the example is formed using a PVDF (polyvinidene fluoride) film,
As shown in Figure 2, on both sides of this PVDF film,
An electrode 42a provided on the front surface with a cut made by a 11I11 mesh, and an electrode 42b provided on the entire back surface are formed.

This piezoelectric element 40 is installed on a soft member 3°, and electrodes 42a and 42b provided on both sides thereof.
Lead wires 44 and 44 for extracting the generated voltage are respectively connected to the terminals.

The present embodiment has the above configuration, and its operation will be explained next.

Drive the actuator 26 of the ultrasonic vibration generator 2o,
When the vibrating member 24 is caused to vibrate ultrasonically, the first diaphragm 34 fixed to the vibrating member 24 vibrates ultrasonically. This vibration is caused by the high-density fluid 38 enclosed within the hollow member 32.
(mercury in the embodiment) to the second diaphragm 36, causing it to vibrate.

This vibration becomes air vibration and is applied to the piezoelectric element 40 installed to face the second diaphragm 36. When air vibration is applied to the piezoelectric element 40 in this way, electric polarization occurs due to the positive piezoelectric effect, and a voltage is generated. This voltage is applied to the piezoelectric element 4 as shown in FIG.
It is taken out from the lead wire 44 via electrodes 42a and 42b provided on both sides of the wire.

FIG. 3 shows an experimental device for testing the characteristics of the power generator of this example.

In this test, the length of the hollow member 32 for vibration transmission means was set to 2
0crrl, the second diaphragm 36 and the piezoelectric element 4
0 was set to 50 mm, and the relationship between the ultrasonic vibration frequency and the voltage output from the piezoelectric element 40 was measured.

In addition, in the test, a sponge was used as the 5° soft member.

As a result of this measurement test, it was confirmed that the output voltage shown in FIG. 4 could be obtained from the power generation device of the example.

As described above, according to the present invention, the vibration of the vibrating member 24 can be applied to the piezoelectric element 4o as gaseous ultrasonic vibration, and the piezoelectric element 40 can generate electricity without contact.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible within the scope of the invention.

For example, in the embodiment described above, flat shaped diaphragms were used as the first and second diaphragms 34 and 36, but the present invention is not limited to this, and it is possible to use various shaped diaphragms as necessary. For example, a corrugated diaphragm may be used to increase the vibration displacement.

Further, in this embodiment, the hollow member 32 and the diaphragms 34 and 36 are made of stainless steel, but the present invention is not limited to this, and various other materials may be used as long as they are mercury-resistant. I can do it. In addition, high-density fluid 38
When a material other than mercury is used as the material, the hollow member 32 is made of various materials compatible with the material. Diaphragms 34 and 36 may be used.

Further, in the embodiment, the electrodes 4 are provided on both sides of the piezoelectric element 40.
Although the electrodes 2a and 42b are formed to intersect, the present invention is not limited to this, but any electrode shape or shape can be used as long as the voltage generated by the positive piezoelectric effect can be taken out.

Further, in the above embodiment, the case where air is present between the second diaphragm 36 and the piezoelectric element 40 has been described as an example, but the present invention is not limited to this, and the present invention is not limited to this, and the present invention is not limited to this. Even in an atmosphere, voltage can be generated satisfactorily using the same principle.

Furthermore, in the embodiment described above, a relatively hard stainless steel pipe was used as the hollow member 32.
The present invention is not limited to this, and if necessary, the hollow member 32 can be formed using a flexible vibrator or the like,
By doing so, the vibration transmission path from the vibration member 24 to the piezoelectric element 40 can be arbitrarily set.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the basic configuration of a power generation device using ultrasonic vibration according to the present invention; FIG. 2 is an explanatory diagram showing an example of the electrode shape of the piezoelectric element used in this embodiment; Figure 4 is an explanatory diagram of the test equipment for measuring the characteristics of the power generation device of this example, Figure 4 is an explanatory diagram of measurement test data measured using the test equipment shown in Figure 3, and Figure 5 is the conventional FIG. 2 is an explanatory diagram showing an example of a power generation device using a piezoelectric element. 20... Ultrasonic vibration generator, 24... Vibration member, 2
6... Actuator, 30... Vibration transmission section, 32... Hollow member, 34...
...First diaphragm, 36...Second diaphragm, 38...Fluid, 40...Piezoelectric element Fig. 3 Fig. 4 Agent: Patent attorney, Fuyuki Fu (and 1 other person) Vibration frequency ( KH2)

Claims (2)

[Claims] (1) Ultrasonic vibration generating means comprising a piezoelectric element, a vibrating member that vibrates in an ultrasonic frequency range, and a vibration transmitting means that transmits the vibration of the vibrating member to the piezoelectric element, The transmission means includes a vibration transmission hollow member of a predetermined length, the interior of which is filled with a high-density fluid as a vibration transmission medium, and whose openings at both ends are closed with diaphragms, one of the diaphragms being fixed to the vibration member. and the other diaphragm is formed to face the pressure receiving surface of the piezoelectric element with a predetermined interval therebetween, and applies the vibration of the vibrating member to the piezoelectric element as an ultrasonic vibration of the gas existing between the piezoelectric element and the piezoelectric element. A power generation device using ultrasonic vibration, which is characterized by generating power with a piezoelectric element in a non-contact manner. (2) According to claim (1), the vibration transmission means is formed as a flexible cable, and the vibration transmission path is formed so as to be arbitrarily set. Device.