JP2000294431A - Soundproofing - Google Patents

Abstract

(57) [Summary] [Problem] To provide a soundproofing device that is lightweight and has a large amount of noise attenuation. A vibration plate (1) in which a pair of a piezoelectric vibrator (vibration sensor) and a piezoelectric vibrator (vibrator) is arranged to face a noise source.
And the piezoelectric vibrator 2 outputs an electric signal 2S proportional to the displacement of the mechanical vibration of the vibration plate 1 to the polarity reversing device 5.
This polarity inversion device 5 inverts the polarity of the output signal 2S from the piezoelectric vibrator 2 and sends it to the piezoelectric vibrator 6, and the piezoelectric vibrator 6 is mechanically proportional to the output signal 5S from the polarity inversion device 5. Vibration is applied to diaphragm 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soundproofing device for suppressing noise generated from an induction device such as a transformer or a reactor, and more particularly to a lightweight soundproofing device having a high soundproofing effect.

[0002]

2. Description of the Related Art Induction devices such as transformers and reactors having windings wound around an iron core generate magnetostrictive vibrations of the iron core, vibrations caused by magnetic force between magnetic steel plates, electromagnetic waves between winding conductors and between windings. Noise is generated by vibration due to force. This noise also resonates with a radiator attached to the outside of the tank, further expands, and is radiated to the surroundings.

Heretofore, in order to reduce this noise, a measure has been taken by providing a soundproof wall surrounding the whole of the induction device around the induction device. FIG. 7 is a cross-sectional view showing a configuration of a conventional soundproofing device. The entirety of the transformer 19 mounted on the ground 21 is covered with a soundproof wall 22. This soundproof wall 22 is a concrete wall having a thickness of several hundred mm.
The noise from the transformer 19 as a noise source can be attenuated by about 15 dB by the soundproof wall 22.

[0004]

However, the above-described conventional soundproofing device has a high soundproofing effect, but has a problem that the soundproof wall 22 is heavy. That is, the soundproof wall 2
2 was very heavy because it was made of concrete and thick, so the transportation cost to the installation site was high, and it was a very uneconomical soundproofing device. As another soundproofing device, there is a relatively light device called a vibration damping shield plate.

FIG. 8 is a sectional view showing the structure of a different conventional soundproofing device. A damping shield plate 23 is attached to a side wall of the transformer 19. The vibration damping shield plate 23 is
A porous material 25 is interposed between 4, 4 and 26, and the porous material 25 has a sound insulating effect. Although the vibration damping shield plate 23 is lightweight, on the other hand, the noise attenuation amount is small, and only about 5 dB is attenuated. An object of the present invention is to provide a soundproof device that is lightweight and has a large amount of noise attenuation.

[0006]

According to the present invention, a vibration sensor and a vibrator are provided on a diaphragm arranged opposite to a noise source. An electric signal proportional to the displacement of the mechanical vibration of the diaphragm is output to the control unit, and the control unit generates an output signal for generating a vibration having an opposite phase to the mechanical vibration of the diaphragm based on the output signal from the vibration sensor. It is preferable that the vibration is sent to the vibrator, and the vibrator applies mechanical vibration to the diaphragm in proportion to an output signal from the control unit. The diaphragm attempts to mechanically vibrate due to the noise from the noise source, and the vibration sensor captures a displacement proportional to the vibration to generate an electric signal. The control unit outputs a signal for generating a vibration having a phase opposite to that of the mechanical vibration of the diaphragm based on the electric signal. The vibrator mechanically vibrates the diaphragm according to the output signal of the control unit. This causes the vibrator to apply vibration to the diaphragm in a phase opposite to the mechanical vibration of the diaphragm due to the noise from the noise source. On the other hand, the vibrator attempts to mechanically vibrate the diaphragm in the opposite direction. Therefore, even if the noise reaches the diaphragm, the vibration is canceled at the diaphragm, and the noise is not transmitted to the non-noise source side of the diaphragm. Therefore,
With this configuration, noise is attenuated to the same degree as in the case of a conventional soundproof wall. Further, in the soundproofing device according to the present invention, the diaphragm can be formed of a thin plate having a thickness of 1 mm or less, so that the soundproofing device can be much lighter than a soundproofing device using a soundproof wall.

[0007] In this configuration, the vibration sensor may be a piezoelectric vibrator. When the diaphragm vibrates mechanically due to the noise from the noise source, a force generated by the vibration is applied to the piezoelectric vibrator, so that the piezoelectric vibrator outputs an electric signal proportional to the displacement of the vibration, thereby forming a vibration sensor.

In this configuration, the vibration sensor includes a coil provided in proximity to the diaphragm, and a transmitting unit for applying a high-frequency voltage to the coil, wherein the transmitting unit has a magnitude of the high-frequency voltage. It is preferable to output an electric signal proportional to. When the coil is excited at a high frequency, a magnetic field is formed around the coil. An eddy current is generated in the diaphragm to cancel this magnetic field. When the diaphragm mechanically vibrates due to the noise from the noise source, the mutual inductance between the diaphragm and the coil in the portion where the eddy current flows changes. That is, when the diaphragm approaches the coil, the mutual inductance increases. On the other hand, when the diaphragm moves away from the coil, the mutual inductance decreases. Therefore, the output impedance of the transmitting unit changes, and the magnitude of the high-frequency voltage transmitted from the transmitting unit changes in inverse proportion to the magnitude of the mutual inductance. Since this high-frequency voltage changes according to the displacement of the vibration, this voltage can be used as the output signal of the vibration sensor.

In this configuration, the vibration sensor includes a movable core fixed to the diaphragm and a winding wound around the movable core, and a voltage induced in the winding is used as an output signal. It is good to do so. When the diaphragm mechanically vibrates due to the noise from the noise source, the movable iron core also vibrates, so that a voltage proportional to the displacement of the vibration is induced in the winding. Therefore, the induced voltage of this winding can be used as the output signal of the vibration sensor.

In addition, a vibrator is provided on a diaphragm arranged opposite to the noise source, and a microphone is provided on the opposite side of the diaphragm from the noise source. The microphone is generated by mechanical vibration of the diaphragm. An electric signal having a waveform corresponding to the sound wave is output to the control unit, and the control unit sends an output signal for generating a vibration having a phase opposite to that of the sound wave to the vibrator based on an output signal from the microphone. The device may apply a mechanical vibration to the diaphragm in proportion to an output signal from the control unit. The diaphragm attempts to mechanically vibrate due to the noise from the noise source. The vibration generates a sound wave on the opposite side of the diaphragm from the noise source, and the microphone detects the sound wave and converts the sound wave into an electric signal. Based on the electric signal, the control unit outputs a signal for generating a vibration having a phase opposite to that of the sound wave. Here, since the mechanical displacement of the diaphragm is proportional to the magnitude of the sound wave, the output signal from the microphone is a signal proportional to the mechanical displacement of the diaphragm, and the output signal of the control unit is the diaphragm. Is a signal that generates a vibration having a phase opposite to that of the mechanical vibration. The vibrator mechanically vibrates the diaphragm according to the output signal of the control unit. This causes the vibrator to apply vibration to the diaphragm in a phase opposite to the mechanical vibration of the diaphragm due to the noise from the noise source. On the other hand, the vibrator attempts to mechanically vibrate the diaphragm in the opposite direction. Therefore, even if the noise reaches the diaphragm, the vibration is canceled at the diaphragm, and the noise is not transmitted to the non-noise source side of the diaphragm. Therefore, even with this configuration, the noise is attenuated to the same degree as in the case of the conventional soundproof wall. Also, the soundproofing device according to the present invention can be formed of a thin plate having a thickness of 1 mm or less, so that the soundproofing device can be made much lighter than a soundproofing device using a soundproof wall.

In this configuration, the vibrator may be a piezoelectric vibrator. Since the electric signal from the polarity reversing device is applied to the piezoelectric vibrator, the piezoelectric vibrator itself mechanically vibrates in proportion to the magnitude of the electric signal. That is, the piezoelectric vibrator has reversibility, and outputs an electric signal when receiving a pressure, and mechanically displaces when receiving an electric signal. Therefore, the piezoelectric vibrator can be used as a vibrator for the diaphragm.

In this configuration, the vibrator includes a movable core fixed to a diaphragm, and a winding wound around the movable core, and the output signal of the polarity reversing device is applied to the winding. It may be applied. Since the electric signal from the polarity reversing device is applied to the winding, the movable iron core mechanically vibrates in proportion to the magnitude of the electric signal.
That is, the movable core and the winding constitute a solenoid and are reversible. When the movable core vibrates, the winding outputs an electric signal, and when the electric signal is applied to the winding, the movable core vibrates. Therefore, the movable core vibrates the diaphragm.

In this configuration, a plurality of pairs of the vibration sensor and the vibrator or a pair of the microphone and the vibrator are provided, and the plurality of pairs are scattered on the diaphragm. Good. As a result, noise that spreads over a wide area can be prevented.

In this configuration, the noise source may be an induction device. Thus, noise generated from the induction device can be shielded. Also,
In such a configuration, the noise source may be covered with a diaphragm. The noise from the noise source can be prevented from spreading to the surroundings.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. FIG. 1 is a sectional view of a main part showing a configuration of a soundproofing device according to an embodiment of the present invention.
Are interposed between the piezoelectric vibrators 2 and 6. An output signal 2S from the piezoelectric vibrator 2 is input to the polarity reversing device 5, and another output signal 5S from the polarity reversing device 5 is output.
Are input to the two piezoelectric vibrators 6. The polarity inversion device 5 is supplied with power from the power supply 4. A noise source (not shown) is provided at the left end of FIG. 1, and a diaphragm 1 is provided so as to face noise from the direction of arrow A.

In FIG. 1, the diaphragm 1 is a thin plate having a thickness of 1 mm or less, and is easily displaced in the thickness direction when receiving a noise. On the other hand, the support 18 is made of, for example, a pillar, and never vibrates even if it receives noise. The piezoelectric vibrators 2 and 6 are elements that output an electric signal proportional to an external force, and are also called piezo elements. In particular,
There are Rochelle salt and barium titanate. The piezoelectric vibrators 2 and 6 are reversible, and displace themselves mechanically in proportion to voltage application. Therefore, when the vibration plate 1 vibrates in response to noise, the piezoelectric vibrator 2 generates an output signal 2S according to the right and left vibration of the vibration plate 1. The polarity inversion device 5 is a control unit, and inverts the polarity of the output signal 2S to output the output signal 5S. The piezoelectric vibrator 6 outputs the output signal 5
Upon receiving S, the diaphragm 1 is vibrated right and left. That is, the piezoelectric vibrator 2 is a vibration sensor that outputs an electric signal 2S proportional to the mechanical vibration displacement of the vibration plate 1, and the piezoelectric vibrator 6 applies a mechanical vibration proportional to the output signal 5S to the vibration plate 1. It is a shaker. Although the diaphragm 1 is mechanically displaced by noise, the piezoelectric vibrator 6 as a vibrator attempts to mechanically displace the diaphragm 1 in the opposite direction. Therefore, even if the noise reaches the diaphragm 1, the noise is canceled at the diaphragm 1, and the noise is not transmitted to the right side of the diaphragm 1. With this configuration, the noise is attenuated to the same degree as the conventional soundproof wall. Further, since the diaphragm is a thin plate having a thickness of 1 mm or less, the soundproof device is lighter than the conventional one.

FIG. 2 is a sectional view of a main part showing a configuration of a soundproofing device according to another embodiment of the present invention.
A coil 37 provided slightly apart from the diaphragm 1,
The transmission unit 33 applies a high-frequency voltage V to the coil 7. This transmitting section 33 is provided with a high-frequency voltage V
Is output to the polarity reversing device 5 in proportion to the magnitude of the electric signal 33S. Further, the coil 37 is fixed to the support 18 via the support 34. The polarity reversing device 5 and the transmitting unit 33 are supplied with power from the power supply 4. An output signal 5S of the polarity reversing device 5 is input to a piezoelectric vibrator 6 which is a vibrator. 2 are the same as those in FIG. 1 and the same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 2, when the coil 37 is excited at a high frequency, a magnetic field H is formed around it. An eddy current is generated in the diaphragm 1 to cancel the magnetic field H. When the diaphragm 1 mechanically vibrates due to the noise from the noise source, the mutual inductance between the diaphragm 1 and the coil 37 in the portion where the eddy current flows changes. That is, when the diaphragm 1 approaches the coil 37, the mutual inductance increases.
On the other hand, when the diaphragm 1 moves away from the coil 37, the mutual inductance decreases. Therefore, the output impedance of the transmitting unit 33 changes, and the magnitude of the high-frequency voltage V transmitted from the transmitting unit 33 changes in inverse proportion to the magnitude of the mutual inductance. Since the high-frequency voltage V changes in accordance with the displacement of the vibration, the voltage V can be used as the output signal 33S of the vibration sensor 7. The polarity reversing device 5
Upon receiving the output signal 33S, the polarity of the output signal 33S is inverted to output the output signal 5S. The piezoelectric vibrator 6 vibrates the diaphragm 1 left and right in response to the output signal 5S. Although the diaphragm 1 is mechanically displaced by noise, the piezoelectric vibrator 6 as a vibrator attempts to mechanically displace the diaphragm 1 in the opposite direction. Therefore, even if the noise reaches the diaphragm 1, the noise is canceled at the diaphragm 1, and the noise is not transmitted to the right side of the diaphragm 1. With this configuration, the noise is attenuated to the same degree as the conventional soundproof wall, and the soundproof device is lighter than the conventional soundproof wall.

FIG. 3 is a sectional view of a main part showing a configuration of a soundproofing apparatus according to still another embodiment of the present invention. A vibration sensor comprising a winding 9 and a movable core 10 between a diaphragm 1 and a support 18 is shown. 30 and a vibrator 31 including a winding 13 and a movable iron core 14 are interposed. The output signal 9S from the winding 9 is input to the polarity reversing device 5 and the output signal 5S from the polarity reversing device 5 is
Has been entered. The polarity inversion device 5 is supplied with power from the power supply 4. The rest of FIG. 3 is the same as the configuration of FIG.

In FIG. 3, movable iron cores 10 and 14 are
The left end is fixed to the diaphragm 1, and the right end is fixed to a support 18 via cushion materials 11 and 16. The windings 9 and 13 are wound around movable iron cores 10 and 14, respectively, and are fixed to supports 18 via supports 12 and 15, respectively. The vibration sensor 30 and the vibrator 31 are so-called solenoids, and have the same configuration. When the diaphragm 1 vibrates due to noise, the movable iron core 10 moves left and right, so that a voltage proportional to the movement is induced in the winding 9, and this induced voltage becomes an output signal 9S. The polarity inversion device 5 receives the output signal 9S, and inverts the polarity of the output signal 9S to output the output signal 5S. Since the winding 13 is excited by the output signal 5S, the movable iron core 14 moves to vibrate the diaphragm 1 left and right. Although the diaphragm 1 is mechanically displaced due to noise, the vibrator 31 attempts to mechanically displace the diaphragm 1 in the opposite direction. Therefore, even if the noise reaches the diaphragm 1, the noise is canceled at the diaphragm 1, and the noise is not transmitted to the right side of the diaphragm 1. With this configuration, the noise is attenuated to the same degree as the conventional soundproof wall, and the soundproof device is lighter than the conventional soundproof wall.

In the embodiment shown in FIGS. 1 to 3,
The vibration sensor and the vibrator may be mounted on any surface of the diaphragm 1, or the vibration sensor and the vibrator may be mounted on surfaces opposite to each other. It is only necessary that the vibrator applies a vibration having a phase opposite to the detected mechanical vibration of the diaphragm 1 to the diaphragm 1. With such a configuration, the vibration is canceled at the diaphragm 1 and the noise is not transmitted to the right side of the diaphragm 1, that is, to the non-noise source side. However, in a configuration in which both the vibration sensor and the vibrator are attached to either one surface of the diaphragm 1, a common support 18 is used for both the vibration sensor and the vibrator.
, So that the configuration becomes simpler.

FIG. 4 is a cross-sectional view of a main part showing a configuration of a soundproof device according to still another embodiment of the present invention. A microphone 17 and a piezoelectric vibrator 6 are interposed between a diaphragm 1 and a support 18. ing. An output signal 17S from the microphone 17 is input to the polarity reversing device 5, and an output signal 5S from the polarity reversing device 5 is input to the piezoelectric vibrator 6. The polarity inversion device 5 is supplied with power from the power supply 4. The rest of FIG. 4 is the same as the configuration of FIG.

In FIG. 4, the diaphragm 1, the piezoelectric vibrator 6, and the support 18 are the same as those in FIG. The microphone 17 and the diaphragm 1 are arranged slightly apart from each other, and the microphone 17 is fixed to a support 18 via a support 32. The microphone 17 receives the sound wave B transmitted through the diaphragm 1 and outputs an electric output signal 17S. The polarity inversion device 5 receives the output signal 17S and inverts the polarity of the output signal 17S to output the output signal 17S.
Output S. The piezoelectric vibrator 6 is a vibrator, and vibrates the diaphragm 1 left and right in response to the output signal 5S. Although the diaphragm 1 is mechanically displaced by noise, the piezoelectric vibrator 6 as a vibrator attempts to mechanically displace the diaphragm 1 in the opposite direction. Therefore, even if the noise reaches the diaphragm 1, the noise is canceled at the diaphragm 1, and the noise is not transmitted to the right side of the diaphragm 1. With this configuration, the noise is attenuated to the same degree as the conventional soundproof wall, and the soundproof device is lighter than the conventional soundproof wall.

In FIG. 4, the microphone 17
Is required to be provided on the anti-noise source side of the diaphragm 1,
The piezoelectric vibrator 6 serving as a vibrator may be attached to any surface of the diaphragm 1, and the vibrator applies vibration having a phase opposite to the sound wave detected by the microphone 17 to the diaphragm 1. Just do it. With such a configuration, the vibration is canceled at the diaphragm 1 and noise is generated on the right side of the diaphragm 1,
That is, it is not transmitted to the anti-noise source side. However, the configuration in which both the microphone and the vibrator are provided on the anti-noise source side of the diaphragm 1 allows both the microphone and the vibrator to be supported by the common support 18, so that the configuration is simpler. Configuration.

In the embodiment shown in FIGS. 1 to 4,
Although the configuration in which the polarity inversion device 5 is used as a control unit that drives an exciter in response to an output signal from a vibration sensor or a microphone has been described, the present invention is not limited to such a configuration. Any configuration may be used as long as a drive signal for generating a vibration having a phase opposite to the mechanical vibration of the diaphragm 1 based on an output signal from a vibration sensor or a microphone is provided to the vibrator. That is, not only a configuration in which the polarity inversion device 5 inverts the polarity of the output signal from the vibration sensor or the microphone by the polarity inversion device 5 as a control unit but also outputs a shaker drive signal, , For example, to select one of the winding polarities of the winding 13 of the vibrator 31 in the embodiment of FIG. 3, or to place the vibrator on any surface of the diaphragm 1 Depending on the choice of mounting, the control unit outputs a vibrator drive signal of the same polarity as the output signal from the vibration sensor or microphone, and the vibrator vibrates in the opposite phase to the mechanical vibration of the diaphragm from the vibrator. It is also possible to add it to the plate 1.

FIG. 5 is a cross-sectional view showing a configuration of a soundproofing apparatus according to still another embodiment of the present invention. The transformer 19 as a noise source is entirely covered with the diaphragm 1 of the soundproofing device. The lower portion of the support 18 is fixed to the ground 21 and is disposed on the anti-transformer 19 side of the diaphragm 1. A plurality of pairs 20 of a vibration sensor and a vibrator or pairs 20 of a microphone and a vibrator are interposed between the diaphragm 1 and the support 18. The pair 20 may have any of the configurations shown in FIGS. The pair 20 may be a combination of any one of the vibration sensor or the microphone and the vibrator shown in FIGS. Multiple pairs 20
Are scattered above, below, before and after the diaphragm 1, so that noise that spreads over a wide area can be prevented at the diaphragm 1.

FIG. 6 is a sectional view showing the structure of a soundproofing apparatus according to still another embodiment of the present invention. Transformer 19
Are covered with the diaphragm 1. The rest of FIG. 6 is the same as FIG. Although some noise leaks from the upper surface of the transformer 19, there is a sufficient sound insulation effect near the outside of the diaphragm 1. Diaphragm 1 on top of transformer 19
Is omitted, the cost of the soundproofing device can be reduced.

Although the embodiment of FIGS. 5 and 6 is a case where the noise source is a transformer, the soundproofing device according to the present invention has the following features.
It is not limited to the case where the noise source is an induction device such as a transformer. The soundproofing device according to the present invention can be applied to, for example, any noise source that generates noise, such as a rotating electric machine, a vehicle, and factory equipment.

In the embodiment of FIG. 5 or FIG.
The pair 20 composed of the vibration sensor and the vibrator is the diaphragm 1
May be attached to either side of the surface. That is, 20
May be attached to the anti-transformer 19 side of the diaphragm 1. In either case, the vibration is canceled at the diaphragm 1 and the noise is not transmitted to the non-noise source side of the diaphragm 1.

[0030]

As described above, according to the present invention, a vibration sensor and a vibrator are provided on a vibration plate arranged opposite to a noise source, and the vibration sensor is proportional to a displacement of mechanical vibration of the vibration plate. The controller outputs an electric signal for generating a vibration having a phase opposite to the mechanical vibration of the diaphragm to the vibrator based on the output signal from the vibration sensor. By applying mechanical vibration to the diaphragm in proportion to the output signal from the control unit, the weight of the vessel is reduced without impairing the soundproofing effect as compared with the case of a soundproof wall, and the transportation cost to the installation site is reduced. It can be significantly reduced.

In addition, a vibrator is provided on a diaphragm arranged opposite to the noise source, and a microphone is provided on a side of the diaphragm opposite to the noise source. The microphone is generated by mechanical vibration of the diaphragm. An electric signal having a waveform corresponding to the sound wave is output to the control unit, and the control unit sends an output signal for generating a vibration having a phase opposite to that of the sound wave to the vibrator based on an output signal from the microphone. By applying mechanical vibration to the diaphragm in proportion to the output signal from the control unit, the weight can be reduced without impairing the soundproofing effect compared to the case of a soundproof wall, and the cost of transportation to the installation site can be reduced. Can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is an essential part cross-sectional view showing a configuration of a soundproofing device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part showing a configuration of a soundproofing device according to a different embodiment of the present invention.

FIG. 3 is an essential part cross-sectional view showing a configuration of a soundproofing device according to still another embodiment of the present invention.

FIG. 4 is a sectional view of a main part showing a configuration of a soundproofing device according to still another embodiment of the present invention.

FIG. 5 is a sectional view showing a configuration of a soundproofing device according to still another embodiment of the present invention.

FIG. 6 is a sectional view showing a configuration of a soundproofing apparatus according to still another embodiment of the present invention.

FIG. 7 is a sectional view showing the configuration of a conventional soundproofing device.

FIG. 8 is a sectional view showing the configuration of a different conventional soundproofing device.

[Explanation of symbols]

1: diaphragm, 2, 6: piezoelectric vibrator, 5: polarity reversing device,
7, 30: vibration sensor, 9, 13: winding, 10, 14:
Movable iron core, 17: microphone, 19: transformer, 2
0: Pair, 31: Exciter, 33: Transmitter, 37: Coil

Claims (10)

[Claims] A vibration sensor and a vibrator are provided on a vibration plate disposed opposite to a noise source, and the vibration sensor outputs an electric signal proportional to a displacement of mechanical vibration of the vibration plate to a control unit. The control unit sends an output signal for generating a vibration having a phase opposite to the mechanical vibration of the diaphragm to the vibrator based on the output signal from the vibration sensor, and the vibrator outputs an output from the control unit. A soundproof device characterized by applying mechanical vibration to a diaphragm in proportion to a signal. 2. The soundproofing device according to claim 1, wherein said vibration sensor is a piezoelectric vibrator. 3. The soundproofing device according to claim 1, wherein the vibration sensor includes a coil provided in proximity to the diaphragm, and a transmitting unit that applies a high-frequency voltage to the coil. A soundproofing device which outputs an electric signal proportional to the magnitude of the high frequency voltage. 4. The soundproofing device according to claim 1, wherein the vibration sensor includes a movable core fixed to a diaphragm, and a winding wound around the movable core. A soundproofing device characterized by using a voltage as an output signal. 5. A vibrator is provided on a diaphragm arranged opposite to a noise source, and a microphone is provided on a side opposite to the noise source of the diaphragm, and the microphone is generated by mechanical vibration of the diaphragm. An electric signal having a waveform corresponding to the sound wave is output to the control unit, and the control unit sends an output signal for generating a vibration having a phase opposite to that of the sound wave to the vibrator based on an output signal from the microphone. The soundproofing device applies mechanical vibration to the diaphragm in proportion to an output signal from the control unit. 6. The soundproofing device according to claim 1, wherein said vibrator is a piezoelectric vibrator. 7. The soundproofing device according to claim 1, wherein the vibrator comprises a movable core fixed to a diaphragm, and a winding wound around the movable core. A soundproofing device, wherein an output signal of the polarity reversing device is applied to a winding. 8. The soundproofing device according to claim 1, wherein a plurality of pairs of said vibration sensor and said vibrator or a plurality of pairs of said microphone and said vibrator are provided. A soundproofing device wherein pairs are scattered on the diaphragm. 9. The soundproofing device according to claim 8, wherein said noise source is an induction device. 10. The soundproofing device according to claim 9, wherein said noise source is covered with a diaphragm.