JPH10206221A - Seismic device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To detect an earthquake evenly in any horizontal direction when detecting an earthquake. SOLUTION: A cylindrical piezoelectric member 9 having uniform vibration detection sensitivity over the entire circumferential direction of a horizontal plane has a first inside.
An electrode 10 is provided on the outside, and a second electrode 11 is provided on the outside.
One end of the first electrode 10 is fixed to a substrate 14 on which an electric circuit is mounted, and a weight 12 is attached to the other end. This simplifies the signal processing because it can be configured with a single set of detection circuits, and is also simpler for the vector synthesis.
Since multiplication and addition are not required, the detection circuit can be configured with a battery having a limited voltage range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic device installed in a gas meter or the like to detect earthquake vibration.

[0002]

2. Description of the Related Art Conventionally, this type of seismic device is disclosed in
One such as Japanese Patent No. 95421 has been known. Less than,
The configuration will be described with reference to FIG.

As shown in FIG. 11, piezoelectric plastic films 1 and 2 orthogonal to each other, squaring circuits 3 and 4 for squaring the electromotive force signals of the piezoelectric plastic films 1 and 2, and squaring circuits 3 and 4 respectively. Addition circuit 5 for adding the signals of
And a square root circuit 6 for square rooting the signal of the adder circuit 5 and a MOSFET 7 for impedance conversion of the signal of the square root circuit 6. Here, 8 is an output terminal.

In the above structure, the electromotive force signals Va and Vb of the orthogonal piezoelectric plastic films 1 and 2 are output signals Va = K · F · cos for a vibration F in a certain direction θ.
(Θ), Vb = K · F · sin (θ). Then, by square addition of these signals and square root,

[0005]

(Equation 1)

Can be detected. Here, K is a proportionality constant.

[0007]

However, in the above prior art, there is a problem that two square circuits are required to detect the output voltage of the piezoelectric plastic film in two directions, which is complicated. In the squaring circuit, since the voltage value is squared, a circuit configuration in a very wide voltage range is required, and it is very difficult to configure the circuit in a limited voltage range of a power supply such as a battery.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a piezoelectric member having uniform vibration detection sensitivity over the entire circumferential direction in a horizontal plane and outputting an electric signal according to the vibration level. Provided with vibration detecting means.

According to the above invention, the sensitivity is uniform in the horizontal circumferential direction, and the signal processing can be configured by a single set of detection circuits, so that the configuration can be simplified. Further, since addition of squares for vector synthesis is not required, the detection circuit can be configured with a power supply having a limited voltage range such as a battery.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has a vibration detecting means comprising a piezoelectric member having a uniform vibration detecting sensitivity in all circumferential directions in a horizontal plane and outputting an electric signal in accordance with the detected vibration level. And it has a uniform sensitivity in the horizontal circumferential direction, and the signal processing can be configured by one set of detection circuits, so that a simple configuration can be achieved. Further, since addition of squares for vector synthesis is not required, the detection circuit can be configured with a power supply having a limited voltage range such as a battery.

Also, a cylindrical piezoelectric member, a first electrode electrically connected to the inner wall of the cylindrical member of the piezoelectric member, a second electrode electrically connected to the outer wall of the cylindrical member, and one end of the piezoelectric member. A swingable weight is provided, and the other end is a fixed end. Since the cylindrical piezoelectric member can have uniform sensitivity in the circumferential direction in the horizontal direction, detection in all directions in the horizontal direction can be constituted by one set of processing circuits.

Further, the first member inserted into the inside of the cylinder of the piezoelectric member.
One end of the conducting wire was connected to the substrate so that the center axis of the conducting wire was perpendicular to the substrate, and a weight was provided at the other end of the conducting wire. Further, the substrate was arranged such that the plate surface became a horizontal plane. Then, by installing the piezoelectric member vertically on the substrate, the substrate can be installed horizontally to detect horizontal vibration.

A first connector in which the first electrode and the second electrode are respectively connected to electric terminals, and one end of a cylindrical piezoelectric member is fixed uniformly over the entire circumference, and a piezoelectric member which is connected to the second electrode. And a second connector as a weight portion for electrically shielding the other end of the second connector. By uniformly fixing one end of the piezoelectric member over the entire circumference, uniform vibration sensitivity can be obtained in the entire circumferential direction, and the other end of the piezoelectric member is shielded by the second connector connected to the second electrode. This makes it possible to provide a vibration detection unit with less noise.

Further, an inert gas is provided inside the storage container.
A piezoelectric member provided with the first electrode and the second electrode, and a weight were provided. Then, by inserting an inert gas into the storage container, corrosion of the electrode can be prevented.

[0015] Further, a nonconductive liquid, a piezoelectric member having a first electrode and a second electrode, and a weight portion are provided inside the storage container. Then, by injecting the liquid into the storage container, the vibrator is prevented from vibrating at high speed due to the viscosity of the liquid, and only low-frequency vibration can be detected.

Further, the apparatus is provided with an inclination detecting means for detecting the contact between the weight portion and the storage container. Also, a weight portion electrically connected to the first electrode, a storage container electrically connected to the second electrode, and a first contact state that the weight portion and the storage container are in contact with each other.
An inclination detecting means for electrically detecting the contact between the electrode and the second electrode is provided. In addition, the vibration level is detected by the piezoelectric member, and the inclination can be detected by the deflection of the cylindrical piezoelectric member due to the contact between the storage container and the weight.

A piezoelectric member on a disk adhered to the diaphragm, an electrode for detecting an electromotive force from the piezoelectric member, and a circumferentially symmetrical vibrator provided at the center of the diaphragm;
At least a part of the outer periphery of the diaphragm was a fixed end. Also,
The diaphragm was arranged so as to be horizontal. Since the disc-shaped piezoelectric member can have uniform sensitivity in the circumferential direction in the horizontal direction by the circularly symmetric vibrator, detection in all directions in the horizontal direction can be constituted by one set of processing circuits.

Further, an inert gas is provided inside the storage container.
A vibration plate, a piezoelectric member, an electrode, and a vibrator were provided. Then, by inserting an inert gas into the storage container, corrosion of the electrode can be prevented.

Further, a non-conductive liquid, a vibration plate, a piezoelectric member, and a vibrator are provided inside the storage container. Then, by injecting the liquid into the storage container, the vibrator is prevented from vibrating at high speed due to the viscosity of the liquid, and only low-frequency vibration can be detected.

Further, there is provided a vibration detecting means comprising a piezoelectric member having uniform vibration detecting sensitivity over the entire circumferential direction of the three-dimensional space and outputting an electric signal according to the vibration level. Then, vibrations in any three-dimensional directions can be detected by a single set of electric circuits, and the detection circuit can have a simple configuration. Further, a squaring circuit for vector synthesis is not required, and detection is possible even with a power supply having a limited voltage range such as a battery.

Further, a battery for supplying electricity to the vibration detecting means is provided. By supplying electricity with a battery, vibration can be detected even in a place without a commercial power supply.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 is a configuration diagram of a seismic device according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 9 denotes a cylindrical piezoelectric member as vibration detecting means, 10 denotes a lead wire electrically connected to an inner wall of the piezoelectric member 9, and 11 denotes an electrically connected to an outer wall of the piezoelectric member 9. The weighted second electrode 12 is pivotally attached to a conducting wire 10 as one end of a piezoelectric member 9.
3 is a solder as a fixed end, 14 is a substrate on which an electric circuit is mounted, 15 is a lead wire connecting the second electrode 11 to the substrate 14, and 16 is a conductive member containing the above-mentioned member and filled with an inert gas 17 inside. It is a storage container of sex. Here, 18 is a solder for connecting the conducting wire 10 and the weight portion 12, 19 is a solder for electrically connecting the storage container to the second electrode 11, 20 is a coating film of a piezoelectric member, 21 is a screw for fixing the substrate, 22 is a case for fixing the seismic device.

As shown in FIG. 2, the electric circuit for detecting the vibration includes a preamplifier 23 for amplifying the electromotive force of the piezoelectric member 9, a signal amplifying means 24, the first electrode 10, and the storage container 1.
Tilt detecting means 25 which detects a tilt by detecting contact with the sensor 6
And a battery 26 for supplying electricity to these electric circuits. Here, 27 is an output unit of the signal detecting means 24, 28
Is an output unit of the inclination detecting means 25.

Next, the operation and operation will be described with reference to FIGS. As shown in FIG. 3, the piezoelectric member 9 for detecting vibration includes a piezoelectric member 9 around a conductive wire 10 and a second member.
The electrode 11 and the coating film 20 are formed concentrically.
Then, one end of the conductive wire 10 was bonded to the substrate 14 with solder 13, and the weight portion 12 was bonded to the other end of the conductive wire 10 with solder 18. With such a configuration, when horizontal vibration occurs, the weight portion 12 vibrates in the horizontal direction as shown in FIG. As a result, distortion occurs in the piezoelectric member 9 and an electromotive force is generated. This electromotive force is applied to the amplifier 23 of FIG.
And an electric output corresponding to the vibration level can be obtained. Here, as shown in FIG. 3, since the shape is concentrically symmetrical with respect to the circumferential direction, as shown in the sensitivity characteristic shown in FIG. Can be detected.

As shown in FIG. 6, when the seismic device is tilted with respect to the horizontal plane, the weight portion 12 and the storage container 16 come into contact with each other. Is turned on. As shown in FIG. 2, an inclination detecting means 25 for detecting the energized state of the switch mechanism.
Was provided. Since it becomes difficult to detect the vibration when the inclination detecting means 25 is inclined by a predetermined angle or more, it is determined that the inclination is detected and the abnormality of the vibration detection is notified.

Since the inside of the storage container 16 is filled with the inert gas 17, the corrosion of each electrode can be prevented, and the contact with the piezoelectric member 9 can be maintained for many years. In addition, there is a contact between the weight portion 12 and the storage container 16 so that sparks are unlikely to occur even when sparking, so that there is an explosion-proof effect even when used with gas appliances or the like.

As shown in FIG. 7, a non-conductive liquid 29 is contained in the container 16 in addition to the inert gas. When the weight 12 sinks in the liquid 29, the movement of the weight 12 can be slowed down, so that relatively low-frequency vibrations can be detected and only low-frequency vibrations can be detected. become. Therefore, it is not necessary to use a low-pass filter or the like in the electric circuit, the power consumption of the electric circuit can be reduced, and the responsiveness to power on / off can be quickened.

Further, as shown in FIG. 8, a first electric terminal 30 to which the conductive wire 10 is engaged and joined, and a second electrode 31 to which one end of the cylindrical piezoelectric member 9 is fixed uniformly over the entire circumference.
A first connector 33 provided with a second electrical terminal 32 for engaging and joining the second connector 31; a second connector 34 serving as a weight connected to the second electrode 31 to electrically shield the other end of the piezoelectric member 9; The first connector 33 was fitted to the third connector 35 provided on the substrate 14 and installed. Where 36 is an insulator,
37 is a third electrode connected to the conductor 10. Then, by fitting the first connector 33 and the third connector 35,
The piezoelectric member 9 can be attached perpendicular to the substrate 14. If the substrate 14 is set horizontally, it is inevitable that horizontal vibrations can be detected. Also, the second
Since the terminal end of the piezoelectric member 9 is shielded by the connector 34, no noise is picked up, so that low noise vibration detecting means can be provided. In addition, since the electrodes can be manufactured only by clamping each electrode, the productivity is good.

As described above, even in the case where vibration in any direction is not known to occur, it is possible to detect vibration in any horizontal direction with equal sensitivity by using one piezoelectric member and a set of detection circuits. it can. Further, since addition of squares for vector synthesis is not required, the detection circuit can be configured with a power supply having a limited voltage range such as a battery. By uniformly fixing one end of the piezoelectric member over the entire circumference, uniform vibration sensitivity can be obtained in the entire circumferential direction, and the other end of the piezoelectric member is shielded by the second connector connected to the second electrode. This makes it possible to provide a vibration detection unit with less noise. Further, by putting an inert gas into the storage container 16, corrosion of the electrode can be prevented. Then, by injecting the liquid into the storage container 16, it is possible to suppress the vibrator from vibrating at high speed due to the viscosity of the liquid, and to detect only low-frequency vibration. In addition, while detecting the vibration level with the piezoelectric member,
When the cylindrical piezoelectric member bends due to the inclination, the inclination can be detected from the contact between the storage container and the weight.

(Embodiment 2) FIG. 9 is a configuration diagram showing a seismic device according to Embodiment 2 of the present invention. The difference from the first embodiment is that a disc-shaped piezoelectric member 39 adhered to a thin diaphragm 38, a lead wire 40 as two electrodes for detecting an electromotive force from the piezoelectric member 39, and a central portion of the diaphragm 38 A concentric columnar vibrator 41 and at least a part of the outer periphery of the diaphragm 38 are fixed ends 42. And the diaphragm 3
8 are arranged in the horizontal direction, and the storage container 43 is filled with the inert gas 17. Further, an electric circuit 44 for detecting an electric signal is housed in this storage container. Here, 45 is a signal output line, and 46 is a substrate.

Next, the operation and operation will be described with reference to FIG. As shown in FIG. 10, when the vibration in the horizontal direction occurs, the vibrator 41 vibrates so as to fall on the diaphragm 38. At this time, the diaphragm 3 joined to the lower end of the vibrator 41
8 causes distortion, and the piezoelectric member 39 bonded to the diaphragm 38 causes distortion. As a result, an electromotive force is generated from the piezoelectric member 39, and the vibration can be detected by amplifying the electromotive force in the same manner as in the first embodiment.

The disk-shaped piezoelectric member 39 and the columnar vibrator 41 are symmetrical in the circumferential direction.
Vibration detection means having equal sensitivity in any horizontal direction can be provided. The electric circuit is also provided in the storage container 43.
The sensitivity characteristics depending on the temperature can also be corrected by putting it in the space.

The same effect can be obtained even if the vibrator 41 is installed below the diaphragm 38 as shown in FIG. By sealing the non-conductive liquid 29 in the storage container 43 to such an extent that the vibrator 41 is immersed, only low-frequency vibration can be detected as in the first embodiment.

As described above, since the disc-shaped piezoelectric member 39 can have uniform sensitivity in the horizontal circumferential direction by the circularly symmetric vibrator 41, detection in all horizontal directions can be performed by one set of processing circuits. Can be configured. In addition, storage container 4
The electrode 3 can be prevented from being corroded by introducing the inert gas 17 into the inside of the electrode 3. By putting the liquid 29 into the storage container 43, the vibrator is prevented from vibrating at high speed due to the viscosity of the liquid, and only low-frequency vibration can be detected.

(Embodiment 3) FIG. 12 is a block diagram showing a seismic device according to Embodiment 3 of the present invention. The difference from the first embodiment is
A spherical piezoelectric member 47 having uniform vibration detection sensitivity in the entire circumferential direction of the three-dimensional space, and a spherical weight portion 48 inside the piezoelectric member 47 are electrically bonded to the inner wall of the spherical piezoelectric member 47. The first electric terminal 49 and the second electric terminal 50 electrically bonded to the outer wall of the piezoelectric member 47 are provided.
Here, 51 is a lead wire for detecting an electromotive force, 52 is a coating of the lead wire 51, 53 is a container, and 54 is a piezoelectric member 47.
Is an elastic body.

Next, the operation and operation will be described. When vibration occurs, the spherical weight 48 vibrates in the vibration direction. At that time, the spherical piezoelectric member 47 is pressed against the elastic body 54 to cause distortion. The electromotive force generated at that time is amplified and detected as a vibration signal. Since the weight portion 48 has a spherical shape and the piezoelectric member 47 also has a spherical shape, it is possible to detect vibration with equal sensitivity in any three-dimensional direction. Here, since each electric terminal has a shape sufficiently thin with respect to the vibrator and the piezoelectric member, the vibration in the direction of the electric terminal can be detected in substantially the same manner as in other directions.

As described above, vibrations in any three-dimensional directions can be detected by one set of electric circuits, and the detection circuit can have a simple configuration. Further, a squaring circuit for vector synthesis is not required, and detection is possible even with a power supply having a limited voltage range such as a battery.

[0038]

As apparent from the above description, the following effects can be obtained according to the seismic device of the present invention.

By providing vibration detection means comprising a piezoelectric member having uniform vibration detection sensitivity in all circumferential directions in a horizontal plane and outputting an electric signal in accordance with the detected vibration level,
Vibration can be detected uniformly in the horizontal circumferential direction,
In addition, signal processing can be configured with a single set of detection circuits, so that a simple configuration can be achieved. Further, since addition of squares for vector synthesis is not required, the detection circuit can be configured with a power supply having a limited voltage range such as a battery.

Also, a cylindrical piezoelectric member, a first electrode electrically connected to an inner wall of the cylindrical member of the piezoelectric member, a second electrode electrically connected to an outer wall of the cylindrical member, and one end of the piezoelectric member. A swingable weight is provided, and the other end is a fixed end. Since the cylindrical piezoelectric member can have uniform sensitivity in the circumferential direction in the horizontal direction, detection in all directions in the horizontal direction can be constituted by one set of processing circuits.

Further, the first piezoelectric member inserted inside the cylinder of the piezoelectric member
One end of the conducting wire was connected to the substrate so that the center axis of the conducting wire was perpendicular to the substrate, and a weight was provided at the other end of the conducting wire. Further, the substrate was arranged such that the plate surface became a horizontal plane. Then, by installing the piezoelectric member vertically on the substrate, the substrate can be installed horizontally to detect horizontal vibration.

Further, a first connector in which the first electrode and the second electrode are respectively connected to electric terminals and one end of a cylindrical piezoelectric member is fixed uniformly over the entire circumference, and a piezoelectric member which is connected to the second electrode. And a second connector as a weight portion for electrically shielding the other end of the second connector. By uniformly fixing one end of the piezoelectric member over the entire circumference, uniform vibration sensitivity can be obtained in the entire circumferential direction, and the other end of the piezoelectric member is shielded by the second connector connected to the second electrode. This makes it possible to provide a vibration detection unit with less noise.

In addition, an inert gas,
A piezoelectric member provided with the first electrode and the second electrode, and a weight were provided. Then, by inserting an inert gas into the storage container, corrosion of the electrode can be prevented.

Further, a non-conductive liquid, a piezoelectric member having a first electrode and a second electrode, and a weight are provided inside the container. Then, by injecting the liquid into the storage container, the vibrator is prevented from vibrating at high speed due to the viscosity of the liquid, and only low-frequency vibration can be detected.

Further, there is provided an inclination detecting means for detecting that the weight portion and the storage container are in contact with each other. In addition, the weight portion electrically connected to the first electrode, the storage container electrically connected to the second electrode, and the fact that the weight portion and the storage container are in contact with each other are electrically determined by the contact between the first electrode and the second electrode. And an inclination detecting means for detecting the inclination. In addition, the vibration level is detected by the piezoelectric member, and the inclination can be detected by the deflection of the cylindrical piezoelectric member due to the contact between the storage container and the weight.

A piezoelectric member on a disk adhered to the diaphragm, an electrode for detecting an electromotive force from the piezoelectric member, a vibrator provided at the center of the diaphragm and having a circumferentially symmetric shape,
At least a part of the outer periphery of the diaphragm was a fixed end. Also,
The diaphragm was arranged so as to be horizontal. Since the disc-shaped piezoelectric member can have uniform sensitivity in the circumferential direction in the horizontal direction by the circularly symmetric vibrator, detection in all directions in the horizontal direction can be constituted by one set of processing circuits.

In addition, an inert gas,
A vibration plate, a piezoelectric member, an electrode, and a vibrator were provided. Then, by inserting an inert gas into the storage container, corrosion of the electrode can be prevented.

Further, a non-conductive liquid, a vibration plate, a piezoelectric member, and a vibrator were provided inside the storage container. Then, by injecting the liquid into the storage container, the vibrator is prevented from vibrating at high speed due to the viscosity of the liquid, and only low-frequency vibration can be detected.

Further, a vibration detecting means comprising a piezoelectric member having a uniform vibration detecting sensitivity in the entire circumferential direction of the three-dimensional space and outputting an electric signal according to the detected vibration level is provided. Then, vibrations in any three-dimensional directions can be detected by a single set of electric circuits, and the detection circuit can have a simple configuration. Further, a squaring circuit for vector synthesis is not required, and detection is possible even with a power supply having a limited voltage range such as a battery.

Also, a battery for supplying electricity to the vibration detecting means is provided. By supplying electricity with a battery, vibration can be detected even in a place without a commercial power supply.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a seismic device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a flow of an electric signal of the seismic sensor.

FIG. 3 is a sectional plan view of a piezoelectric member of the seismic device.

FIG. 4 is a side sectional view showing a state where a weight portion of the seismic device is vibrated.

FIG. 5 is a sensitivity characteristic diagram of the seismic sensor.

FIG. 6 is a side sectional view when the entire seismic sensing device is inclined.

FIG. 7 is a side sectional view when a non-conductive liquid is put in a storage container of the seismic device.

FIG. 8 is a side sectional view illustrating a connector portion of the seismic device.

FIG. 9 is a side sectional view of a seismic device according to a second embodiment of the present invention.

FIG. 10 is a side sectional view illustrating the operation of the seismic device.

FIG. 11 is a side cross-sectional view when the vibrator of the seismic device is provided below the diaphragm.

FIG. 12 is a sectional view of a seismic device according to a third embodiment of the present invention.

FIG. 13 is a configuration diagram showing a conventional seismic device.

[Explanation of symbols]

 9, 39, 47 Piezoelectric member 10 Conductor (first electrode) 11 Second electrode 12, 48 Weight 13 Solder (fixed end) 14, 46 Substrate 16, 43 Storage container 17 Inert gas 25 Tilt detecting means 26 Battery 29 Liquid 30, 49 First electrical terminal 32, 50 Second electrical terminal 33 First connector 34 Second connector 35 Third connector 38 Vibration plate 40 Lead wire (electrode) 41 Vibrator

Claims (15)

[Claims] 1. A seismic device comprising vibration detecting means having a piezoelectric member which has a uniform vibration detecting sensitivity over all circumferential directions in a horizontal plane and outputs an electric signal according to a vibration level. 2. A piezoelectric member is formed into a cylindrical shape, and a first electrode electrically connected to a cylindrical inner wall of the piezoelectric member, a second electrode electrically connected to a cylindrical outer wall of the cylindrical member, and one end thereof. The seismic device according to claim 1, further comprising a swingable weight provided on the other end of the fixed first electrode. 3. The sensing device according to claim 2, wherein a substrate on which an electric circuit is mounted is provided, the first electrode is a conductor, and the conductor is connected to the substrate so that a center axis of the conductor is orthogonal to the substrate. Quake device. 4. The seismic device according to claim 3, wherein the substrate is arranged so that the plate surface is a horizontal plane. 5. A first connector in which a first electrode and a second electrode are respectively connected to an electric terminal and one end of a cylindrical piezoelectric member is fixed, and the other end of the piezoelectric member connected to the second electrode. The seismic device according to claim 3, further comprising a second connector as a weight portion for electrically shielding. 6. A storage container for storing vibration detecting means,
The seismic device according to claim 2, wherein an inert gas is sealed in the storage container. 7. A storage container for storing vibration detection means,
The seismic device according to claim 2, wherein a non-conductive liquid is sealed in the storage container. 8. The seismic device according to claim 5, further comprising an inclination detecting means for detecting the contact between the weight portion and the storage container. 9. The seismic device according to claim 8, wherein the second electrode is electrically connected to the storage container, and the inclination detecting means detects that the weight portion contacts the storage container. 10. A diaphragm bonded to a piezoelectric member on a disk,
The seismic device according to claim 1, further comprising: an electrode that guides an electromotive force from the piezoelectric member; and a vibrator fixed to the diaphragm, wherein at least a part of an outer periphery of the diaphragm is fixed. 11. The seismic device according to claim 10, wherein the diaphragm is arranged to be horizontal. 12. The seismic device according to claim 10, further comprising a storage container for storing the piezoelectric member, wherein the storage container is filled with an inert gas. 13. The seismic device according to claim 10, further comprising a storage container for storing the piezoelectric member, wherein a non-conductive liquid is sealed in the storage container. 14. A seismic device having vibration detecting means made of a piezoelectric material having uniform vibration detecting sensitivity over the entire circumferential direction of a three-dimensional space and outputting an electric signal according to a vibration level. 15. The seismic device according to claim 1, further comprising a battery for supplying electricity to the vibration detecting means.