JPH0579895A - Earthquake sensor - Google Patents

Abstract

PURPOSE:To reduce the number of parts and to make the apparatus compact in a simple structure and to realize lowering of costs and improvement of shock resistances by providing a piezoelectric film horizontally and a plate-like elastic body showing elastic deformation in the vertical direction horizontally. CONSTITUTION:When a box body 2 is vibrated due to the earthquake, the movement of a weight 7 is controlled by an elastic body 3 and a silicone oil 8 to be an attenuation vibration. The attenuation vibration of the weight 7 is, via a piano wire 6, transmitted as the vibration in the vertical direction to a piezoelectric film 4 which is set in the horizontal direction. Although a free end of the film 4 is shifted downward due to the transmission of the vibration, the position of the film 4 in the horizontal direction is hardly changed because the film 4 is fixed to the elastic bode 3 by a fixing member 5. Therefore, the film 4 is shifted downward at the free end thereof without moving in the horizontal direction. As a result, the film 4 is deformed at the upper and lower faces thereof, thereby generating a voltage resulting from tone piezoelectric phenomenon. Since the electrodes are provided at the upper and lower surfaces of the film 4, the vibration of the weight 7 can be detected by reading the voltage between the electrodes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration-sensing device which detects a vibration caused by an earthquake and outputs a signal, and more particularly to a vibration-sensing device mounted on a gas meter or the like which shuts off a gas flow path when an earthquake occurs.

[0002]

2. Description of the Related Art In order to prevent a secondary disaster after an earthquake occurs,
There is a home-use gas meter that is equipped with a seismic sensing device for detecting vibration due to an earthquake and that shuts off a gas flow path when the seismic sensing device detects vibration. As a vibration-sensing device used in such a gas meter, a vibration-sensing device disclosed in Japanese Utility Model Laid-Open No. 61-48325 has a steel ball inside a casing having a conical inner bottom surface, and a steel ball caused by vibration of the casing. Movement is transmitted through the concave spherical surface and the pressing plate, and the vibration-sensitive switch part is configured to open and close the contacts of the switch mechanism. The vibration-sensitive switch part can be swung in the liquid-sealed chamber via the suspension shaft. Is supported by. With this configuration, the inclination due to an error during mounting is corrected.

[0003]

However, in the above-mentioned conventional seismic sensing device, since the operation of the steel ball is transmitted to the contact of the opening / closing mechanism of the switch, the contact state of the contact can be stably maintained for a long period of time. However, there is a problem in that a complicated structure such as a transmission mechanism is required, which leads to an increase in cost and is likely to be damaged by an impact. Further, since the vibration is detected by the movement of the steel balls on the inner bottom surface of the conical shape, it is difficult to adjust the setting sensitivity after manufacturing, and there is a problem that the yield of the products is deteriorated. further,
In addition to the seismic switch part, a liquid sealing chamber with a complicated shape is required, which also increases the cost due to an increase in the number of parts, and there is a problem that it cannot be mounted on the printed circuit board due to the increase in size and shape. It was

An object of the present invention is to transmit the movement of a weight due to the vibration of an earthquake vertically to a part of a horizontally installed piezoelectric film, and detect the voltage generated by the piezoelectric phenomenon on the piezoelectric film to detect the earthquake. It is designed to detect vibrations, reduce the number of parts with a simple structure, downsize the device, and handle mounting on a printed circuit board, thus reducing costs, improving shock resistance, and facilitating adjustment of setting sensitivity. It is to provide a seismic sensing device that can be realized.

[0005]

According to a first aspect of the present invention, there is provided a seismic sensing device for detecting a seismic motion by a voltage generated on a piezoelectric film by a piezoelectric phenomenon. Characterized in that a plate-like elastic body that elastically deforms in a direction is installed horizontally, and the piezoelectric film and the elastic body are provided with a weight held in the vertical direction so as to be horizontally movable via a holding member. And

According to a second aspect of the present invention, there is provided a vibration-sensing device in which a guide for restricting a horizontal movement range of the holding member is provided between the elastic body or the piezoelectric film and the weight. is there.

A seismic sensing device according to a third aspect of the present invention is the seismic sensing device according to the first aspect, wherein a portion of the elastic body that causes elastic deformation is formed in a disk shape.

According to a fourth aspect of the present invention, in the seismic sensing device according to the first or second aspect, the piezoelectric film is attached to the elastic body.

The invention described in claim 5 is the same as claims 1 to 3.
In the seismic sensing device according to any one of items 1 to 3, the piezoelectric film is attached to an elastic body different from the elastic body.

The invention described in claim 6 is the same as claims 1 to 5.
In the seismic sensing device according to any one of 1 to 3, the weight is immersed in a liquid.

[0011]

In the vibration-sensing device according to the first aspect, the horizontal movement of the weight is transmitted to the piezoelectric film and the elastic body in the vertical direction via the holding member. The piezoelectric film and the plate-shaped elastic body are installed horizontally, and the piezoelectric film is deformed by the movement of the weight transmitted in the vertical direction from the holding member. Vibration of the weight is detected from the voltage generated in the piezoelectric film by this deformation.

In the seismic sensing device according to claim 2,
The horizontal vibration of the weight is transmitted as vibration to the piezoelectric film via the holding member and the guide.

According to the third aspect of the invention, since the plate-shaped elastic body elastically deforms at the disk-shaped deformed portion, the vibration of the weight is vertical regardless of the vibration direction regardless of the vibration direction. Is transmitted to the piezoelectric film as directional vibration.

In the invention described in claim 4, the vibration transmitted to the piezoelectric film is attenuated by the elastic force of the elastic body.

In the invention described in claim 5, the damping force for the vibration of the weight and the damping force for the piezoelectric film are supplied by different elastic bodies.

According to the sixth aspect of the invention, the vibration of the weight receives the braking action not only from the elastic body but also from the liquid.

[0017]

1 is a plan sectional view, a front sectional view and a side sectional view of a seismic sensing apparatus according to an embodiment of the present invention. The vibration-sensing device 1 horizontally installs a plate-shaped elastic body 3 and a piezoelectric film 4 inside a housing 2, and hangs down a piano wire 6 from the lower surface of the piezoelectric film 4 corresponding to the center position of the elastic body 3. A weight 7 is fixed to an intermediate portion of the piano wire 6. The lower end of the piano wire 6 is fixed to the inner bottom surface of the housing 2. Further, the weight 7 is immersed in the silicone oil 8. A guide 9 is provided between the piezoelectric film 4 and the weight 7 in the center of the inside of the housing 2, and a piano wire 6 penetrates a hole 10 formed in the center of the guide 9. Further, the piezoelectric film 4 is fixed to the elastic body 3 via the fixing member 5 near the free end thereof.

With the above configuration, the housing 2 is subjected to earthquake motion.
When the vibration occurs, the weight 7 moves in the horizontal direction, and this movement is transmitted to the piezoelectric film 4 and the elastic body 3 via the piano wire 6. The movement of the weight 7 is subjected to a braking action by the elastic body 3 and the silicone oil 8, and the movement of the weight 7 becomes damped vibration. The damping vibration of the weight 7 is transmitted to the piezoelectric film 4 via the piano wire 6, but at this time, the piano wire 6 comes into contact with the inner peripheral surface of the hole 10 formed in the guide 9 and the piezoelectric film 4 is transmitted as vibration in the vertical direction. Due to the transmission of this vibration, the free end side of the piezoelectric film 4 is displaced downward. At this time, the position in the horizontal direction hardly changes due to the fixing to the elastic body 3 by the fixing member 5.
Therefore, the piezoelectric film 4 is displaced downward at its free end without moving in the horizontal direction, and is deformed on both upper and lower surfaces thereof. As a result, a voltage is generated in the piezoelectric film 4 due to the piezoelectric phenomenon. Independent electrodes are formed on the upper and lower surfaces of the piezoelectric film 4 so as not to be electrically connected to each other, and the vibration of the weight 7 can be detected by reading the voltage between the electrodes.

FIG. 2 is a plan sectional view, a front sectional view, and XX of a seismic sensing apparatus according to an embodiment of the invention described in claim 3.
FIG. The vibration-sensing device 11 includes an elastic body 13, a piezoelectric film 14, and a weight 17 inside a housing 12. Inside the housing 12, an upper cylindrical portion 19 and a lower rectangular parallelepiped portion 20 are formed, and the cylindrical portion 19 and the rectangular parallelepiped portion 20 communicate with each other. The elastic body 13 has a square flat plate shape, and is installed under the cylindrical portion 19 with its peripheral surface fixed. The piezoelectric film 14 is cantilevered on one inner side surface of the rectangular parallelepiped portion 20, and is fixed to the center position of the elastic body 13 at a part of the free end side thereof. In addition, the elastic body 13
The lower end of the piano wire 16 is fixed to the center position of the upper surface of the, and the upper end of the piano wire 16 is fixed to the upper surface of the cylindrical portion 19. A weight 17 is fixed to an intermediate portion of the piano wire 16. The elastic body 13, the piezoelectric film 14, and the weight 17 are immersed in the silicone oil 18.

With the above structure, when the earthquake motion is transmitted to the housing 12, the weight 17 moves in the horizontal direction. At this time, the elastic force of the elastic body 13 and the silicone oil 18 act as a braking force on the movement of the weight 17, and the movement of the weight 17 becomes damped vibration. This damping vibration in the horizontal direction is transmitted to the elastic body 13 via the piano wire 16 which is a holding member, and the elastic body 1
3 is further transmitted to the piezoelectric film 14 via the fixing member 15. At this time, since the elastic body 13 is horizontally installed in the cylindrical portion 19, the elastic body 13 is deformed in the disk-shaped portion. Moreover, since the lower end of the piano wire 16 is fixed to the center position of the elastic body 13, the central portion of the elastic body 13 produces vertical vibration corresponding to the magnitude of the vibration regardless of the vibration direction of the weight 17. This vertical vibration is transmitted to the free end side of the piezoelectric film 14 via the fixing member 15. Since the free end of the piezoelectric film 14 is fixed to the elastic body 13 via the fixing member 15, it does not move in the horizontal direction. Therefore, when the central portion of the elastic body 13 vibrates in the vertical direction, the free end side of the piezoelectric film 14 also vibrates in the vertical direction without being displaced in the horizontal direction. As a result, the upper and lower surfaces of the piezoelectric film 14 are displaced, and a voltage is generated by the piezoelectric phenomenon. Electrodes which are not in contact with each other are formed on the upper and lower surfaces of the piezoelectric film 14, and the vibration of the weight 17 can be detected by reading the voltage between the electrodes.

FIG. 3 is a plan sectional view, a front sectional view and a side sectional view of a seismic sensing apparatus according to an embodiment of the invention described in claim 4. The piezoelectric element 24 is attached to the lower surface of the elastic body 23 inside the housing 22 of the vibration sensing device 21. With this configuration, the elastic force of the elastic body 23 exerts a braking action on the vibration of the piezoelectric film 24, and the vibration of the piezoelectric film 24 is quickly damped.

FIG. 4 is a plan sectional view and a front sectional view showing a seismic sensing apparatus according to an embodiment of the invention described in claim 5. The piezoelectric film 34 is attached to the upper surface of an elastic body 43, which is different from the plate-shaped elastic body 33, inside the housing 32 of the vibration sensing device 31. With this configuration, the weight 3
The vibration of No. 7 can be damped by the elastic body 33, and the vibration of the piezoelectric film 34 can be damped by the elastic body 43.

A material other than the piano wire 6 may be used as the holding member, and the material of the elastic body 3 can be freely selected.

[0024]

According to the present invention, it is possible to detect the vibration in the horizontal plane due to the earthquake motion by reading the voltage generated in the piezoelectric film, and it is stable for a long period of time because the opening / closing contact is not used for the detection. The reliability can be obtained. Further, since the structure can be made extremely simple, the size and cost of the device can be reduced, and the device can be mounted on the substrate. Further, since the structure of the mechanism portion is simple, there is an advantage that complicated fine adjustment is not necessary and the mechanism can be easily used.

Further, according to the invention described in claims 2 and 3, the seismic motion in all directions in the horizontal plane can be detected by one output signal, and it is not necessary to correct the output signal according to the vibration direction, It is not necessary to provide an arithmetic circuit therefor.

[Brief description of drawings]

FIG. 1 is a plan sectional view, a front sectional view, and a side sectional view of a seismic sensing device according to an embodiment of the invention described in claim 2.

FIG. 2 is a plan sectional view, a front sectional view, and a sectional view taken along the line XX of an earthquake-sensing device according to an embodiment of the present invention.

FIG. 3 is a plan sectional view, a front sectional view, and a side sectional view of a seismic sensing device according to an embodiment of the invention described in claim 4.

FIG. 4 is a plan sectional view and a front sectional view of a seismic sensing device according to an embodiment of the invention described in claim 5;

[Explanation of symbols]

 1-Vibration Sensing Device 2-Housing 3-Elastic Body 4-Piezoelectric Film 6-Piano Wire (Holding Member) 7-Weight 8-Silicon Oil (Liquid) 9-Guide

Claims (6)

[Claims] 1. A seismic sensing device for detecting seismic motion by a voltage generated on a piezoelectric film by a piezoelectric phenomenon, wherein the piezoelectric film is installed horizontally, and a plate-like elastic body that elastically deforms in a vertical direction is installed horizontally. A vibration-sensing device characterized in that a weight that is movable in a horizontal direction through a holding member and that is vertically held by the piezoelectric film and the elastic body is provided. 2. The seismic sensing device according to claim 1, further comprising a guide provided between the elastic body or the piezoelectric film and the weight, the guide limiting the horizontal movement range of the holding member. 3. The seismic sensing device according to claim 1, wherein a portion of the elastic body that causes elastic deformation is formed in a disk shape. 4. The seismic sensing device according to claim 1, wherein the piezoelectric film is attached to the elastic body. 5. The seismic sensing device according to claim 1, wherein the piezoelectric film is attached to an elastic body different from the elastic body. 6. The seismic sensing device according to claim 1, wherein the weight is immersed in a liquid.