JP3396714B2 - Seismic element - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a microcomputer meter of, for example, city gas or propane gas, or to a control device of an oil heater, a gas combustion device or an electric device. The present invention relates to a seismic element used for a seismic sensor which is attached and sends a detection signal to the microcomputer meter or the control device upon sensing a vibration such as an earthquake. 2. Description of the Related Art Conventionally, as this kind of acceleration responsive switch, there is, for example, a "seismic sensor" of Japanese Patent Application No. 4-27287. As shown in FIG. 5, a seismic element 101 used in this seismic device is a contact member 10 which is fixed in a metal hermetically sealed container 102 by glass 103 so as to be electrically insulated from the container.
4 and the conductive ball 105 is stored so as to be swingable,
When the conductive ball oscillates due to vibration, it comes into contact with the electrode, thereby electrically short-circuiting between the container and the electrode to generate a detection signal. [0003] In recent years, such a seismic sensor has been attached to a gas flow meter such as a city gas or a propane gas installed in each household to not only record the flow rate but also prevent a secondary disaster such as a fire caused by an earthquake. In order to provide a function for early detection of gas leakage or the like, a microcomputer type gas flow meter (hereinafter referred to as a microcomputer meter) incorporating a so-called microcomputer has begun to be used. This microcomputer meter has a built-in microcomputer and battery, detects vibrations and overturns caused by earthquakes, abnormally large outflow of gas and long-term outflow even though it is a small amount, closes the built-in solenoid valve etc. and issues an alarm from an alarm Control to prevent accidents caused by these. [0004] Among them, regarding the detection of an earthquake, it is necessary to discriminate between a collision of a flying object with a microcomputer meter and an artificial vibration caused by an automobile running or a construction site from an earthquake vibration. For this purpose, it is necessary for the seismic sensor to exhibit a predetermined operating characteristic in a frequency band which is a vibration region of an earthquake, and to exhibit another operating characteristic in other frequency bands. For example, the vibration of an earthquake is a compound of vibrations of various frequencies, but mainly the vibration of 10 Hz or less, especially 5 Hz or less. For example, 3.3Hz, 2Hz, 1.4
This is performed by applying a 3 Hz sine wave vibration. Therefore, for example, in a seismic device using a seismic sensor having a contact that is turned on and off by the oscillation of an inertia such as the above-described conductive sphere, for example, an ON signal having a duration of 40 ms or more for one time is used. When an off signal is output within a predetermined period of time, for example, three times or more in three seconds, the microcomputer determines that an earthquake has occurred and outputs a signal to distinguish it from other disturbance vibrations. [0006] Since the place where the earthquake occurs is unpredictable and unlimited, the seismic sensor does not have directivity so that it has the same characteristics to seismic waves from any direction. It must be structured. For this reason, the above-mentioned “seismic device”
The seismic element 101 has an inclined surface gradually rising concentrically from the center to the outside on the bottom surface of the container. As shown in FIG. 6A and FIG. Conductive terminal pin 1 insulated and fixed by 103
The contact member 104 is conductively fixed to the end of the contact 06 so that the contact portion is disposed on a circle indicated by the symbol A centering on the conductive terminal pin 106. When the conductive ball 105 swings due to vibration, the contact member 104 is contacted. , The container 102 and the contact member 104 are electrically short-circuited to generate a detection signal. FIG. 6A shows the upper cover 1 of the seismic sensor of FIG.
FIG. 6B is a cross-sectional view showing a state before fixing of 02A to the container main body 102B, and FIG. 6B is a view from the direction of arrow B in FIG. 6A. Reference numeral 107 denotes a conductive ball 105 which is a contact member 104.
And a protective plate for preventing direct deformation in the vicinity of the fixed portion between the conductive pin 106 and the conductive terminal pin 106. However, the seismic element 101 of this "seismic element"
In order to prevent so-called chattering and bouncing that occurs when the contact member 104 and the conductive ball 105 come into contact with each other, the contact member 1 is used so that the contact does not cause a collision between rigid bodies.
04 has a flexible structure. Therefore, for example, a thin conductive material such as 50 μm
When phosphor bronze is used, the contact member 104 is distorted by heat or the like generated when it is fixed to the conductive terminal pin 106 by welding or the like. Although this distortion is slight at the fixed portion, it is enlarged at the tip 104A of the contact member 104, and as a result, the positional relationship of the contact portion located near the tip 104A of the contact member changes before and after the fixation. It is necessary to design parts in anticipation of the change. Further, as shown in FIG. 7 (A) and FIG. 7 (B) which is a view from the direction C, the contact portion to be located on the circle centered on the conductive terminal pin 106 is large, and the ellipse indicated by the distortion symbol D is large. When the conductive sphere 105 rolls, the distance from the center until reaching the contact portion when the conductive sphere 105 rolls varies depending on the rolling direction. The acceleration required for contacting for a predetermined time fluctuates depending on the direction of the vibration,
As a result, the characteristics of the seismic element 101 have an unpredictable directivity. Therefore, instead of directly fixing the contact member 104, a structure in which the contact member 104 does not generate heat during welding by sandwiching and holding the conductive terminal pin 106 and the protection plate 107 has been considered. Since the contact member 104 is sandwiched in the vicinity of the welded portion between the conductive terminal pin 106 and the protective plate 107, heat during welding is transmitted to the contact member, which may generate more distortion than is allowed. According to the present invention, there is provided a seismic element comprising a cover plate fixedly electrically insulated by penetrating conductive terminal pins into a hole formed substantially in the center of a circular metal plate. And a conductive housing having a bottomed cylindrical shape, and a slope that gradually rises concentrically from the center to the outside is formed on the bottom surface of the housing, and a housing is formed on the peripheral edge of the lid plate. The open end of the cover is fixed to form a container, and a plurality of flexible elastic wing-like portions are provided at the end of the conductive terminal pin of the lid plate, in which the contact portion is disposed substantially in a circle around the conductive terminal pin. A conductive contact member made of a conductive material is conductively fixed, and a conductive solid inertial sphere is housed inside the container so as to be positioned substantially at the center of the housing by gravity when stationary in a normal posture, and vibration is suppressed. The inertia ball swings by receiving it, and the contact member In the seismic element configured to contact and displace and slide and simultaneously short-circuit between the inner surface of the housing and the contact member via the inertial sphere, in the vicinity of the fixed portion of the contact member with the conductive terminal pin, A slit is provided to prevent heat generated during fixing and distortion caused by the heat from being transmitted to the outer peripheral portion. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a seismic element 1 of the present invention, FIG. 2 is a plan view of an example of a contact member used in the present invention, FIG. 2 (A) is a plan view thereof, and FIG. FIG.
It is an enlarged view of the E section enclosed by the two-dot chain line of (A). The seismic sensor 1 has a cover plate 5 in which conductive terminal pins 4 are hermetically sealed through a metal plate 2 with an insulating material 3 such as glass or ceramics, and a bottomed cylindrical housing 6. The hermetic container is constituted by fixing the portion to the opening of the housing 6 by ring projection welding or the like. Inside the sealed container, a conductive ball 7, which is a conductive solid inertia ball such as iron, copper, or an alloy thereof, is rotatably accommodated, and is usually concentric from the center of the housing 6 to the outside. It is placed at the center of the inclined surface 6A that gradually rises in a shape, and keeps a predetermined distance in all directions with respect to a contact member described later. A conductive material such as phosphor bronze having a plurality of flexible elastic wing-shaped portions 8A in which a contact portion is disposed substantially in a circle around the conductive terminal pin at the inner end of the conductive terminal pin 4 is provided. The contact member 8 is conductively fixed, and can be brought into contact with the above-mentioned conductive ball 7. Note that several projections 6B are provided on the inner wall of the housing 6, and for example, the conductive ball 7
The projection 6B acts as an abutting portion when the orbital movement is started along the inner wall of the contact hole, and the direction of movement of the conductive sphere 7 is suddenly changed to temporarily break the contact between the contact member 8 and the conductive sphere 7 to turn on the signal. , The kinetic energy of the conductive sphere 7 is rapidly reduced by the collision with the projection 6B, and the orbital motion of the inertial sphere is converged early to return to the normal reciprocating motion. As shown in FIG. 2, a through hole 8B is formed in the center of the contact member 8, and the contact member 8 is fixed to the conductive terminal pin 4 through the through hole 8B. The protective plate 9 is conductively fixed to the substrate 4 by welding or the like. That is, the contact member 8 is not directly fixed to the conductive terminal pins or the like, but is connected to the conductive terminal pins 4 and the protection plate 9.
And held between them. The protection plate 9 is used not only for fixing the contact member, but also by providing the protection plate 9 to prevent the deformation of the contact member due to the contact of the conductive ball 7 near the base of the contact member 8. Further, in the present invention, a slit 8C is provided substantially all around the through hole 8B of the contact member 8, so that distortion due to heat generated when the contact member 8 is fixed is not transmitted to the outer peripheral portion. ing. This point will be described with reference to FIG. 3, which is an enlarged view of a portion F indicated by a two-dot chain line in FIG. 1. The protection plate 9 has its welded portion 9A inserted through the through hole 8B of the contact member 8, and the conductive terminal pin 4 Is fixed to the end of the substrate by a method such as electric resistance welding. At the same time, the contact member 8 closes the periphery 8D of the through hole 8B to the welding portion 9A of the protection plate 9.
Is pinched and held by the pinching portion 9B provided around the end of the conductive terminal pin 4. When the protective plate 9 is welded to the conductive terminal pins 4, the temperature near the welded portion 9A of the protective plate becomes instantaneously high. At this time, since the through hole 8B of the contact member 8 is approximately the same size as the diameter of the welded portion 9A of the protection plate 9 for positioning, and the inner peripheral portion thereof is adjacent to the welded portion, heat during welding is penetrated. The power is transmitted from the inner periphery of the hole 8B to the peripheral portion 8D. Distortion is generated in the peripheral portion 8D due to the welding heat, but since the slit 8C is provided almost all around the peripheral portion 8D, the generated distortion is prevented from being transmitted to the outside of the slit 8C, and the slit which is not distorted. Since the outer peripheral portion is held by the holding portion, it hardly affects the positional relationship of the tip of the contact member. Also, almost no welding heat is transmitted to the outside of the slit 8C, so that distortion does not occur on the outer periphery of the slit and does not affect the positional relationship of the tip of the contact member. In this embodiment, the slit 8C has three arcs, but the number of the arcs is not limited to three. If there is no problem in dimension or strength, the slit 8C may be double or more as shown in FIG. Needless to say, it is even more effective. Further, in the embodiment, the seismic element in which the lid plate and the housing constitute a closed container is described as an example. However, for example, the seismic element is used in a non-fouling atmosphere, or the contact member, the conductive ball and the inner surface of the housing are plated. When the antifouling treatment is performed, a non-hermetic structure may be adopted in which a cover plate is attached to the opening of the housing by caulking or the like. According to the seismic element of the present invention, since the slit is provided so as to surround the fixed portion of the contact member over substantially the entire circumference, the heat generated at the time of fixing by welding or the like or the heat generated by this heat is used. Since the strain is not transmitted to the outside of the slit, when a contact member having a very small thickness is used, the positional relationship of the distal end portion does not change due to the strain generated around the fixed portion.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of an example of a seismic element of the present invention. FIG. 2 is an example of a contact member used in the seismic element of the present invention. (B) is a partial enlarged view of FIG. 3; FIG. 4 is a partial enlarged view of the seismic element of FIG. 1; FIG. 4 is a partial enlarged view of another embodiment of the contact member used in the seismic element of the present invention; FIG. 6 is an example of a contact member and its peripheral members used in a conventional seismic element, (A) is a plan view, and (B) is a B thereof.
FIG. 7 is a view showing a modification of the contact member of FIG. 6;
(A) is a plan view, and (B) is a view from the direction of C. [Description of References] 1: Seismic element 2: Metal plate 3: Insulating material 4: Conductive terminal pin 5: Cover plate 6: Housing 7 : Conductive ball 8: contact member 8A: wing portion 8B: through hole 8C: slit 9: protective plate

Claims (1)

(57) [Claim 1] A cover plate which is electrically insulated and fixed by penetrating conductive terminal pins into a hole formed substantially in the center of a circular metal plate, and a bottomed cylindrical shape. An inclined surface is formed on the bottom surface of the housing, which gradually rises concentrically from the center toward the outside, and the open end of the housing is fixed to the peripheral edge of the lid plate. A contact made of a conductive material having a plurality of flexible elastic wing-shaped portions at the ends of the conductive terminal pins of the cover plate, and arranging the contact portions substantially in a circle around the conductive terminal pins at the ends of the cover plate The member is conductively fixed, and a conductive solid inertial sphere is housed inside the container so as to be located at a substantially central portion of the housing by gravity when stationary in a normal posture, and the inertial sphere is subjected to vibration and the inertial sphere is received. Swing and contact with the contact member to displace In the seismic element configured to slide and simultaneously short-circuit between the inner surface of the housing and the contact member via the inertial sphere, heat generated at the time of fixation near the fixing portion of the contact member with the conductive terminal pin, A seismic element characterized by having a slit to prevent heat distortion from being transmitted to the outer periphery.