JP2914859B2 - Acceleration response switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acceleration responsive switch for detecting an earthquake vibration or the like, and to reliably distinguish an earthquake vibration from a disturbance vibration.

[0002]

2. Description of the Related Art Conventionally, as this kind of acceleration responsive switch, there is, for example, a "seismic sensor" disclosed in Japanese Patent Application No. 4-27287. This seismic sensor has electrodes fixed electrically insulated from this container in a metal container and accommodates conductive balls so that they can swing. By doing so, the container and the electrode are electrically short-circuited 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 incorporates a microcomputer and a battery, detects vibrations and falls due to earthquakes, abnormally large outflows of gas, and long-term outflows of small amounts of gas, etc., 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 distinguish between an impact of a flying object on a microcomputer meter and an artificial vibration caused by a car 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.

[0005] For example, the vibration of an earthquake is a compound of vibrations of various frequencies, but mainly includes vibrations of 10 Hz or less, particularly 5 Hz or less. For example, 3.3 Hz, 2 Hz, 1.
This is performed by applying a 43 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.

In order to distinguish an earthquake from a disturbance vibration in such a manner, the seismic sensor outputs different signals in a frequency band which is a vibration region of the earthquake and in other frequency bands. It is necessary, for example, 3.3 Hz, 2 Hz, 1.4
When a sine wave of 3 Hz is applied, 120 corresponds to seismic intensity 5
The microcomputer outputs a command to generate an earthquake at about gal and activates a safety device such as closing a gas shut-off valve. If the vibration exceeds 5 Hz, for example, 6 Hz to 7 Hz or more, the microcomputer does not perform the control operation even at 300 gal. Must be.

Further, when a control device such as a microcomputer meter itself is greatly inclined or falls due to some reason such as a large earthquake, a repeated signal from the seismic sensor cannot be expected, so that a continuous ON signal is kept for a predetermined time, for example, 1 second or more. When the control is continued, the control device is operated.

[0008]

These conventional control devices, such as a microcomputer meter, are often installed outdoors for meter reading or the like. For example, they are mounted on the outer wall of a building with piping. Therefore, depending on the mounting location, the vehicle may face a path of a person or a playground for children, and may hit a body, luggage, a bicycle, or a catch ball when a person passes. In this case, after a shock wave of 1000 to 3000 gal, the vibration acceleration attenuates from a substantially sinusoidal waveform of about 1000 gal after a shock wave of 1000 to 3000 gal, although there is a slight difference depending on the distance between the supporting positions of the fixing fittings of the gas pipe. It has been found by experiment that is applied to the gas meter.

Since such a vibration has a frequency of about 10 Hz, the signal from the seismic sensor is theoretically synchronized with this cycle, so that at least the on signal or the off signal does not reach 40 milliseconds. Assuming that the off time and the off time are equal, an on signal and an off signal of 25 milliseconds, which is a considerably shorter time interval, are issued, so that the microcomputer does not perform a control operation that recognizes an earthquake.

However, when the impact is large, the inertia may make a rotational movement along the inner wall or the electrode of the container. In this case, a continuous ON signal is generated because the inertia and the electrode are in continuous contact. If the circular motion of the inertial sphere generated by the impact of the disturbance does not quickly converge, the ON signal will continue for more than the set time, and it will not be possible to distinguish it from the signal due to the inclination of the microcomputer meter, etc., and the control device may malfunction. Yes, making it difficult to distinguish between earthquakes and disturbance vibrations.

In addition, a sphere is used as an inertia in a cylindrical or hemispherical container.
In the case of the seismic sensor of No. 87, the orbit can be changed at the time of contact with the contact member, or it intersects the vibration direction due to the difference between the resonance frequency and the excitation frequency due to the shape of the bottom of the housing and the mass of the inertia, etc. Due to the presence of a slight acceleration component in the direction, the inertial sphere deviates from the center of the housing, for example, at a frequency of 7 to 8 Hz, the resonance of the inertial sphere and the movement in that direction are amplified from the conical bottom shape. 8
In some cases, a circular motion such as an orbital motion or an orbital motion such as an elliptical orbit or a circular orbit may be started. Also in this case, the ON signal and the OFF signal are 7 Hz to 8 Hz.
For example, a signal longer than 31 to 36 milliseconds and a signal of 40 milliseconds or longer based on the frequency of the microcontroller may be generated, and the control device malfunctions as described above in order to satisfy the condition for determining the earthquake given to the microcomputer. This makes it difficult to distinguish between earthquakes and disturbance vibrations.

In order to solve such a problem, the applicant of the present invention applied an “acceleration responsive switch” filed on October 1, 1993 by providing a projection on the inner side of the container when the inertial sphere started orbiting. We propose a structure in which the energy of the orbital motion of the inertial sphere is deprived by colliding with the projection, and the orbital motion is converged early by disturbing the resonant motion of the inertial sphere. In addition, in the "acceleration response switch" filed on October 6, 1993, damping liquid is injected into the container together with the inertial sphere, and the undesired rolling of the inertial sphere is suppressed and the rolling is performed in the vibration direction. An application has been filed in which a damping liquid is used to provide a regulating force for regulating the movement in accordance with the above, to prevent the inertial sphere from shifting to the orbital motion due to the resonance motion, and to converge the orbital motion due to the impact early.

However, in the case where the damping liquid is injected into the container, the viscosity of the damping liquid is greatly affected by the temperature thereof. In comparison, when the viscosity of the damping liquid is increased, the inertial sphere becomes difficult to move, and the desired performance may not be obtained. As a countermeasure, there is a method of selecting a damping liquid having sufficient fluidity even at a low temperature, or adjusting the regulating force on the inertial sphere by reducing the injection amount.

However, those having sufficient fluidity even at a low temperature have a lower viscosity at a high temperature of, for example, 60 ° C., so that the regulation effect is reduced. There is a problem that it cannot be used at high temperatures. In addition, even when the injection amount is reduced, the change in the viscosity of the vibration damping liquid remains unchanged. Therefore, when the injection amount is set to operate normally at a low temperature, the regulation effect becomes insufficient at a high temperature. There is a problem. As described above, it is difficult to obtain a stable operation in a wide temperature range from a low temperature to a high temperature in the case of using the vibration damping liquid.

In the case where the projection is provided on the inner side of the container, the operation is always stable from a low temperature to a high temperature because there is no element depending on the temperature. Regulatory effect is somewhat inferior.

[0016]

SUMMARY OF THE INVENTION Therefore, an acceleration responsive switch according to the present invention is a cover plate in which a conductive lead terminal is passed through a hole formed substantially in the center of a substantially circular metal plate with an electrically insulating filler and hermetically fixed. And a bottomed cylindrical conductive housing, on the bottom surface of which is formed an inclined surface that gradually rises concentrically from the center to the outside, and a housing is provided on the peripheral edge of the lid plate. The open ends are hermetically fixed to form an airtight container, and a plurality of flexible elastic members are provided at the lead terminal ends inside the container of the lid plate in a substantially concentric manner around the conductive terminal pins. A contact member made of a conductive material having a wing-shaped portion having the conductive member is conductively fixed, and a conductive solid inertial sphere is positioned in a substantially central portion of the bottom surface of the housing by gravity when stationary in a normal posture in the closed container. To do The inertial sphere rolls by receiving vibration and contacts the contact member to displace and slide its wing-like portion, and at the same time, to short-circuit between the inner surface of the housing and the contact member via the inertial sphere. The inner surface of the housing is provided with an abutting portion on a wall portion with which the inertial ball comes into contact when receiving a predetermined acceleration regardless of the stationary state, and the inertial ball applies a rotational force along the inner wall of the housing. When it is performed, it is configured to intermittently contact the contact portion to change the course and discontinuously disturb the contact between the inertial sphere and the contact member. A predetermined amount of a vibration damping liquid for suppressing excessive rolling is injected.

Another feature is that a pollution preventing gas such as an inert gas is sealed in the space inside the closed container.

Still another feature resides in that the damping liquid has been previously removed of dissolved gas by degassing.

Still another feature is that the damping liquid is a fluorine-based inert liquid.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 show an embodiment of the acceleration responsive switch according to the present invention, and FIG.
2 is a sectional view taken along a line AA of the acceleration responsive switch of FIG. 1. FIG. The acceleration responsive switch 1 has a circular cover plate 2 made of metal. A through hole 2A is formed in the center of the cover plate 2, and a conductive lead terminal 3 is inserted through the through hole 2A. It is hermetically insulated and fixed by an electrically insulating filler 4 such as glass. A flange portion 2B is provided on a peripheral portion of the cover plate 2, and an opening end of a bottomed cylindrical metal housing 5 is air-tightly fixed to the flange portion 2B by a method such as ring projection welding so that the vibration damping liquid is long. The sealed container is configured so as not to leak over a period.

A contact member 6 made of a conductive material is conductively fixed to the tip of the lead terminal 3 on the inner side of the sealed container by welding or the like. The contact member 6 has a plurality of wing-like portions 6A having flexible elasticity, and a contact portion with an inertial ball 7 described later is disposed substantially concentrically around the conductive terminal pin 3. When the mass of the inertial sphere is about 0.7 grams,
As a material of the contact member 6, for example, a thickness of 0.01 to 0.0
A 3 mm phosphor bronze plate is used.

A conductive inertial sphere 7 is housed in the closed container, and is normally located on a stationary portion 5B provided near the center of the conical surface of the housing bottom surface 5A when stationary in a normal posture. . The inertial sphere 7 is a conductive solid sphere such as iron, copper, or an alloy thereof, and is subjected to a surface treatment such as silver plating as necessary. The inertial sphere 7 is made to roll on the housing bottom surface 5A by vibration of a predetermined size or more due to an earthquake or the like.
A can be opened and closed. A protective plate 8 made of a thick metal plate is fixed to the lower surface of the fixed portion between the lead terminal 3 and the contact member 6, and the inertial ball 7 contacts the contact member 6 near the base of the contact member 6 by contact. The deformation of the member is prevented.

A liquid 9 as a vibration damping material is injected into the closed container. This damping liquid 9 is an inert liquid whose viscosity and injection amount are selected. As the vibration damping liquid, a liquid having a relatively low viscosity and a small surface tension, such as a fluorine-based inert liquid such as Fluorinert (trademark, 3M) is desirable. The injection amount is, for example, from １ ／ of the diameter of the inertial sphere 7 to the extent that the whole is covered. Gas is present on the free surface to prevent deformation of the closed container due to expansion and contraction of the damping liquid due to temperature change. ing.

The inner side wall 5E of the container 5 is provided with four projections 5C, which are abutting portions, at equal intervals as shown in FIG. The projections 5C are formed by, for example, press molding, and the number thereof is determined by a resonance frequency determined by the size of the container and the inertial sphere, the material of the inertial sphere, and the like. Alternatively, it may be provided at three places, or may be provided at five or more places. In addition, for reasons such as press working, the inertial sphere 7
Rolling part 5 in a range that can actually move before hitting the side wall 5E
If the shape of D is not affected, the abutting portion such as the projection 5C is located at a position not in contact with the inertial sphere 7 between the maximum movement position of the inertial sphere 7 and the housing side wall 5E shown by a dotted line in FIG. It may be provided in a column shape upward from the outer portion of the housing bottom surface 5A.

The projecting amount of the abutting portion to the inside of the container is such that the contact between the inertial ball 7 and the contact member 6 is not hindered even if the inertial ball 7 is in a position where it comes into contact with the projection 5C, and the contact member 6 is in contact with the projection 5C.
The height is selected so that the circular motion of the inertial sphere can be surely changed course without directly touching the sphere. In addition, by making the circumferential width of the container of the contact portion as narrow as possible, the chance that the inertial ball 7 collides with the contact portion head-on when the inertial sphere reciprocates vibrates to minimize the amplitude is reduced. Other than when the inertial ball 7 collides with the projection 5C, which is an abutting portion, from the front, the inertial ball 7 reaches the side wall 5E of the housing 5 if it strikes at a slight angle, and the amplitude of the inertial ball 7 decreases. The contact time with the contact member 6 is hardly affected.

Next, the operation of the acceleration responsive switch will be described. In the normal posture and at rest, the inertial sphere 7 is located on the stationary portion 5B of the housing bottom surface 5A. In this state, the inertial sphere 7 does not contact the contact member 6 and the lead terminal 3 and the housing 5 and the lid 2 Since no electrical connection is made between them, no signal is output.

When the acceleration responsive switch 1 receives a horizontal vibration equal to or more than a predetermined value, the inertial sphere 7 moves to the housing bottom surface 5A.
The contact member 6 and the housing 5 are electrically short-circuited by rolling on the rolling portion 5D of the contact member 6 and contacting with the wing-shaped portion 6A of the contact member 6, so that the lead terminal 3-contact member 6-inertial sphere 7-
An electric path is formed along the path from the housing 5 to the cover plate 2 to output a signal.

If the vibration reciprocates in a certain direction when the inertial sphere rolls, the inertial sphere theoretically reciprocates on the center line of the housing determined by the vibration direction. However, in reality, the acceleration component in the direction that intersects the vibration direction is very small due to the difference in the resonance frequency and the excitation frequency due to the shape of the bottom of the housing and the mass of the inertia, etc. However, the inertial sphere deviates from the center of the housing due to its existence, and at a certain frequency, the motion in that direction is gradually amplified from the resonance of the inertial sphere and the conical bottom surface shape, and the figure-eight movement, the elliptical orbit, and the like. Orbital motion such as circular orbit may start.

However, in the present invention, since the damping liquid 9 is injected together with the inertial sphere 7 into the closed container, the rolling of the inertial sphere 7 is restricted, and the inertial sphere in the direction orthogonal to the vibration direction is controlled. The rolling of No. 7 is substantially eliminated, and the rolling becomes almost ideal. This is because the resonance frequency of the inertial sphere 7 can be lowered to a region of 1 Hz or less due to the injection of the damping liquid 9 into the closed container, and therefore, the undesired inertial sphere in the direction orthogonal to the vibration direction is not desired. Is not amplified, and the rolling in this direction is very slight in the direction of vibration. Never start.

Here, the kinematic viscosity and the like of the damping liquid 9 are determined by the inertial sphere 7
Are selected so that there is substantially no problem in the contact operation with the electrodes. For example, in the embodiment, a damping liquid having a kinematic viscosity of 0.6 centistokes at room temperature is used as a damping liquid.
When 2 to 0.5 grams were used, the inertial sphere 7 started rolling at 110 gal when the damping liquid 9 was not injected for the sine wave excitation. Has started rolling at 120 gal, and this acceleration is within the range of 80 gal to 250 gal, which corresponds to seismic intensity 5, and there is no substantial problem.

When the frequency is 7 to 8 Hz and the acceleration is increased and the vibration is applied at a value of, for example, 200 to 300 gal, the difference between the resonance frequency and the excitation frequency due to the shape of the bottom surface of the housing and the mass of the inertia, etc. When the damping liquid 9 is not injected and the contact portion is not provided, the inertial sphere 7 moves in a direction intersecting the vibration direction due to a slight acceleration component generated in a direction intersecting the oscillation direction. While the rolling is amplified and the inertial sphere 7 makes an orbital motion and emits an undesired signal, in the case where the damping liquid 9 is injected, almost no such orbital motion is restricted and occurs. The rolling of the inertial sphere 7 can be substantially limited to the rolling in the vibration direction.

Further, for example, when a strong impact is given to a device to which the acceleration responsive switch 1 is attached by hitting a person or a ball, the inertial ball 7 may start to rotate along the housing 5 or the contact member 6. At this time, in the present invention, since the damping liquid 9 is injected and the abutment portion is provided on the inner surface of the housing, the rotational motion can be converged in a short time. Therefore, even if a signal is output, the convergence process is shortened to avoid repetition of the signal that meets the above-described condition, and the microcomputer does not perform an undesired control operation. This is because when the inertial sphere 7 starts orbiting due to an impact, the inertial sphere 7 comes into contact with the projection 5C as an abutting portion to change the trajectory, and the resonance frequency of the inertial sphere 7 is lowered by the damping liquid 9. This is because the orbiting motion cannot be maintained, and the vibration of the inertial sphere cannot be maintained against the vibration damping liquid by the vibration that rapidly attenuates from the time of the impact.

For example, in the embodiment, in the impact test at room temperature, if the damping liquid 9 is not injected and the housing has no contact portion on the inner surface, it takes 2 seconds before the rolling of the inertial sphere converges.
While it took 0 to 30 seconds, in the present embodiment, the rolling of the inertial sphere converged in 10 seconds or less in a similar test.
Therefore, for example, as described above, when the microcomputer determines that an earthquake has occurred when an ON signal and an OFF signal each having a duration of 40 ms or more are output three times or more in 3 seconds, as described above, the 4
Although the ON signal of 0 ms or more is generated in the process of convergence of the rolling of the inertial sphere 7, the rolling of the inertial sphere converges within a range where it does not come into contact with the contact member before it occurs three times. With such a shock, the microcomputer will not make a false judgment that an earthquake has occurred.

When the acceleration-responsive switch into which the damping liquid is injected is used at a low temperature, the viscosity of the damping liquid increases, so that the regulating force for the operation of the inertial sphere increases, and a predetermined vibration is applied. Also, the contact time of the inertial sphere with the contact member is shortened, so that, for example, the above-described ON signal of 40 milliseconds or more may not be output, or furthermore, the inertial sphere may not contact the contact member and no signal may be output. However, in the present invention, the damping liquid 9 is selected so that its viscosity is not more than a predetermined value even at the lowest operating temperature. For example, in the present embodiment, the kinematic viscosity is -30.degree. An on-signal of about 1.5 centistokes is output at 160 gal for a sine wave excitation for a predetermined time, and the acceleration is in the range of 80 gal to 250 gal corresponding to the seismic intensity 5 as described above. .

Of course, at -30.degree.
Even when the vibration is applied with the acceleration of 200 to 300 gal and the vibration of the inertial sphere 7 is restricted by the vibration damping liquid 9 in the direction intersecting the vibration direction of the inertial sphere 7, the rolling of the inertial sphere 7 is restricted. Substantially only rolling in the vibration direction can be performed, and no undesired signal is generated.

Further, in the impact test at −30 ° C.,
In the present embodiment, the rolling of the inertial sphere 7 converges in 10 seconds or less due to the effect of the damping liquid and the contact portion. Therefore, when the ball hits the microcomputer meter or the like, the microcomputer does not mistakenly determine that an earthquake has occurred.

However, in this embodiment, the vibration damping liquid 9 can be used even at a low temperature.
Is selected so that the viscosity does not exceed a predetermined value.
At high temperatures, on the contrary, the viscosity becomes too low, and the regulation effect by the damping liquid 9 may not be sufficiently obtained. Therefore, in the present invention, a projection 5C as an abutting portion is provided on the inner surface of the container 5 in order to compensate for a decrease in the regulation effect of the damping liquid 9. Therefore, even if the viscosity of the damping liquid 9 decreases due to a rise in temperature and its regulating effect decreases, the inertial sphere 7 is restricted from rolling by the projection 5C and shifts to a circular motion similarly to the state at normal temperature. Can be regulated. In addition, when the inertial sphere 7 starts orbiting due to an impact or the like, the inertial sphere 7 can change its direction of movement by abutting against the projection 5C and at the same time deprives the energy of the orbiting motion. Similarly to the above, the orbital motion and rolling of the inertial sphere can be converged at an early stage. At this time, although the damping liquid 9 has a low viscosity, it naturally gives a restricting force to the rolling of the inertial sphere 7, and therefore, the damping liquid 9 can be used in all situations within the range of use. And the contact portion contribute to the early convergence of the rolling of the inertial sphere.

For example, in the present embodiment, at 60 ° C., the kinematic viscosity of the damping liquid 9 is 0.4 centistokes or less, and the inertial sphere 7 starts rolling at 120 gal in response to the sine wave excitation. ing. When the acceleration-responsive switch 1 is vibrated at a frequency of 7 to 8 Hz at 60 ° C. and an acceleration of 200 to 300 gal, the viscosity of the damping liquid 9 decreases, so that the shape of the bottom surface of the housing and the inertia The slight acceleration component generated in the direction intersecting the vibration direction due to the difference between the resonance frequency and the excitation frequency due to the mass of the vibration cannot be sufficiently suppressed by the vibration damping liquid alone. Therefore, when there is no contact portion, the inertia ball 7
The rotation in the direction intersecting with the vibration direction is amplified, and the inertial sphere 7 may start orbiting and emit an undesired signal. However, when the projection 5C serving as the contact portion is provided, the inertial sphere 7 Since the rolling is regulated by the protrusion 5C, the orbiting motion of the inertial sphere can be regulated even with the damping liquid having reduced viscosity.
The rolling of the inertial ball 7 can be substantially limited to the rolling in the vibration direction.

For example, when a strong impact is applied to the device to which the acceleration responsive switch 1 is attached by hitting a person or a ball or the like, and the inertial sphere 7 starts rotating along the housing 5 or the contact member 6, the temperature becomes high. Although the regulation effect by the vibration damping liquid 9 is weakened below, in the present embodiment, since the projection 5C as the contact portion is provided, the motion direction of the inertial sphere 7 is changed and the kinetic energy is deprived by the contact with the projection 5C. Therefore, the orbital motion and rolling of the inertial sphere can be converged in a short time in cooperation with the damping liquid 9. Therefore, even if the signal is output, by shortening the convergence process, it is possible to avoid the repetition of the signal that meets the above conditions,
The microcomputer does not perform an undesired control operation.

For example, in an impact test at 60 ° C., when there is no contact portion, the convergence of the rolling of the inertial
In the embodiment, the rolling of the inertial sphere 7 converges in 10 seconds or less, while it takes about seconds. Therefore, the microcomputer does not mistakenly judge that an earthquake has occurred when an impact such as a person or a ball hits the microcomputer meter.

Further, in the present invention, by injecting the inert damping liquid 9 into the closed container, minute foreign matters are less likely to adhere to the surfaces of the contact member 6 and the inertial sphere 7, and
When the inertial sphere 7 agitates the vibration damping liquid 9 to generate a flow during vibration, these minute foreign substances are easily dropped. Therefore, the electric signal is assured, and the desired performance can be maintained for a long period of time.

In this embodiment, the viscosity of the vibration damping liquid 9 is selected, and an example in which the viscosity of the vibration damping liquid 9 is set to a value that is equal to or less than a predetermined value even at −30 ° C. has been described. The regulating effect on the inertial sphere 7 may be adjusted by adjusting the injection amount instead of using the one. For example, if a damping liquid having a kinematic viscosity of about 0.8 centistokes at room temperature and a kinematic viscosity of about 3.5 centistokes at -30.degree. In the case of 0.5 g, at -30 ° C., the rolling of the inertial sphere is suppressed by the damping liquid, and no ON signal is output for a predetermined time even for a sine wave of 300 gal.

Therefore, by reducing the regulating effect of the damping liquid applied to the inertial sphere by setting the injection amount of the damping liquid to, for example, 0.1 g or less, even when the kinematic viscosity of the damping liquid increases, the inertial sphere rolls. Will not be regulated more than necessary. In addition, when the kinematic viscosity of the damping liquid decreases at high temperatures, etc., and the regulation effect is reduced, the energy of the rotational motion of the inertial sphere is deprived by the provision of the abutment part, and the regulation effect is reduced by the damping liquid. The minutes are compensated and the orbital motion of the inertial sphere can be quickly converged.

Normally, in these acceleration-responsive switches, the operating voltage is relatively low and the current is weak, so that if an oxide film or the like is formed on the surface of the contact member and the inertial sphere or on the inner surface of the container, the contact resistance greatly changes. Therefore, the container of the switch body is a sealed container, and an inert gas such as helium or argon, nitrogen, or hydrogen is substituted and sealed in the internal space as a gas for preventing contamination, thereby preventing generation of an oxide film or the like. In particular, when helium is contained, an airtight inspection can be performed with a helium leak detector, which is preferable.

In order to prevent an oxide film or the like from being formed on the surface of the contact member and the inertial sphere or the inner surface of the container due to a gas such as oxygen dissolved in the damping liquid, the damping liquid from which the dissolved gas has been removed in advance by degassing is used. By injecting the gas together with the inert gas into the inside, it is possible to obtain an acceleration responsive switch having stable characteristics for a long time without invading each member. In addition, by performing a surface treatment such as silver plating on the surfaces of the contact member and the inertial sphere and the inner surface of the container, not only the influence of the dissolved gas is eliminated, but also it is not necessary to replace and seal the antifouling gas into the internal space.

The shape of the contact portion is not limited to the protrusion as shown in FIG. 1. If the inertial sphere suddenly changes its moving direction and reduces its kinetic energy when it moves into a rotating motion, the kinetic energy can be reduced. For example, as shown in FIGS. 3 and 4, a structure in which an abutting member is fixed in a housing may be adopted.
In this embodiment, the same members as those in the above-described example are denoted by the same reference numerals, and description thereof will be omitted. The damping liquid 9 having a selected viscosity or the like is also injected into the container of the acceleration responsive switch 21 of this embodiment, and regulates the orbital movement and undesired rolling of the inertial sphere 7.

The contact member 22 of this embodiment is formed of, for example, a metal such as iron or its alloy, a resin, or the like.
As shown in (A) and (B), contact portions 22B are provided at equal intervals on a ring-shaped base portion 22A. By inserting and fixing the base portion 22A into the bottomed cylindrical housing 23, the contact portions 22B are arranged at predetermined positions. In the embodiment, eight contact portions are provided at equal intervals. Since the base 22A of the contact member 22 is ring-shaped and the rolling portion of the inertial ball 7 is located inside the ring, the contact member 22 does not affect the basic rolling characteristics of the inertial ball 7. .

The effect of the contact portion 22B of the contact member 22 is the same as that of the above-described projection 5C. However, since the contact member 22 is a member separate from the housing, for example, the material is thinner than the housing. By using a material which is easily deformed or elastically deformable, it can be designed so that it can absorb more kinetic energy of the inertial sphere 7 than the projection 5C which is close to a rigid body at the time of contact with the inertial sphere 7. 9, the rolling of the inertial sphere 7 can be made to converge more quickly.

As shown in the cross sectional view of the housing 35 shown in FIG. 6, the side wall 35A of the housing is made polygonal or has a non-circular cross-sectional shape by changing the curvature.
A may be a substantially abutting portion so that the orbiting motion of the inertial sphere 7 along the inner surface of the housing 35 is made unstable, and the motion is converged by the damping liquid by the regulation effect. Also in this case, the cross-sectional shape of the inertial ball rolling portion 35C on the housing bottom surface 35B is not changed and the basic rolling characteristics of the inertial ball 7 are not affected. In addition, if the shape is designed in consideration of the relative size to the diameter of the inertial sphere 7 so as to minimize the difference in the on-time caused by the difference in the rolling distance depending on the rolling direction of the inertial sphere 7, the vibration of the vibration can be substantially reduced. There is no hindrance to detection.

FIG. 7 shows an example in which these acceleration responsive switches are attached to a microcomputer meter or the like. The vibration sensor 11 houses the acceleration responsive switch 1 in a case 12. A suspending portion 13 is provided on the lead terminal 3 of the acceleration responsive switch 1 and is swingably suspended on a hanger 14A of a holding body 14 provided in the case 12. Normally, the acceleration responsive switch 1 is automatically operated normally. The posture is set. One ends of flexible lead wires 15A and 15B are electrically connected to the cover plate 2 and the lead terminal 3 of the acceleration responsive switch 1, and the other ends of the lead wires are connected to the connection terminals 16A and 16A.
It is connected to conductive terminals 17A and 17B insert-molded in case 12 via 16B. A predetermined amount of a viscous fluid 18 is filled in the case 12, and an outer lid 19 is hermetically sealed at the open end of the case 12 to such an extent that the viscous fluid 18 does not leak.

The vibration sensor 11 is directly attached to a printed circuit board or the like of the control device, and is connected to wiring on the circuit board by conductive terminals 17A and 17B. Due to the structure of the acceleration responsive switch according to the present invention, the mounting posture greatly affects the operation characteristics. For example, when the switch is tilted once from the normal posture, the operation acceleration changes by about 20 gal. Since high accuracy is required for the mounting posture, it is very difficult to mount the acceleration responsive switch 1 directly on the printed circuit board in the normal posture. However, in the case of the seismic sensor 11, the acceleration responsive switch 1 is suspended in the case 12, so that if the mounting posture of the seismic sensor is within the range of the allowable inclination angle, the acceleration responsive switch 1 is automatically set in the normal posture by its own weight. Therefore, no extra precision is required for the mounting, and the work becomes easy.

The case 12 has an acceleration responsive switch 1
At the same time, since the viscous fluid 18 such as silicone oil whose viscosity is selected is injected, the acceleration responsive switch is used when the device to which the seismic sensor 1 is mounted falls down or suddenly tilts or when vibration such as an earthquake occurs. 1 generates an operation signal substantially following the movement of the case 12. Further, the viscous fluid 18 is selected so as to return to a normal posture within 30 seconds, for example, with respect to inclination at the time of mounting. As described above, the seismic sensor having the structure as shown in FIG. 2 can be easily mounted, and can reliably detect the vibration of the earthquake, the sharp inclination and the fall.

Each numerical value in the above embodiment is a matter of design, and it is clear that the injection amount and the viscosity of the damping liquid are different from the numerical values according to the design change. The acceleration value at which the inertial sphere starts rolling in the embodiment can be adjusted by changing various conditions such as the shape of the bottom surface of the housing.

Although the acceleration responsive switch used for the seismic sensor 11 of the embodiment has a metal cover plate in the embodiment, the vibration damping liquid 9 and the viscous fluid 1 have been described.
Resin or ceramics may be used as long as a sufficient airtight container can be formed for the conductive member 8 and the conductive lead terminals can be insulated and fixed. In this case, one end of the lead wire 15A shown in FIG.

[0055]

According to the present invention, by injecting the damping liquid into the housing, undesired rolling of the inertial sphere due to disturbance is suppressed, and the rolling of the inertial sphere is reduced with respect to the vibration given to the acceleration responsive switch. It is possible to eliminate the uncertainty of the signal due to the elliptical motion of the inertial sphere like the conventional one by making the reciprocating motion faithful and the viscosity of the damping liquid at high temperature by providing the abutment on the inner surface of the housing. Of the regulation effect due to the decrease in

When the inertial sphere rolls due to an impact, the orbiting motion and the undesired rolling can be quickly converged by the damping liquid and the contact portion, and the signal output time in the convergence process is shortened. By doing so, it is possible to avoid repetition of signals that match the earthquake detection conditions by the microcomputer, prevent malfunction of the microcomputer meter, and provide a reduction in the regulation effect due to a decrease in the viscosity of the damping liquid at high temperatures on the inner surface of the housing. It can be supplemented by abutments.

By replacing and sealing the antifouling gas in the space inside the sealed container, the formation of an oxide film or the like on the surfaces of the contact member and the inertial sphere or the inner surface of the container is prevented.

Further, by removing the dissolved gas from the damping liquid in advance by degassing, it is possible to obtain an acceleration responsive switch having stable characteristics for a long period of time without affecting each member. In addition, by performing a surface treatment such as silver plating on the surfaces of the contact member and the inertial sphere and the inner surface of the container, not only the influence of the dissolved gas is eliminated, but also it is not necessary to replace and seal the antifouling gas into the internal space.

Further, in the present invention, by injecting a fluorine-based inert liquid as a damping liquid into a closed container,
There is no concern that the damping liquid itself will attack the contact members and the surface of the inertial sphere, and it will be less likely that dirt will adhere to each member. Dirt is easy to remove. Therefore, the electric signal is assured, and the fluorine-based inert liquid is stable, so that the desired performance can be maintained for a long time.

[Brief description of the drawings]

FIG. 1 is an embodiment of an acceleration responsive switch according to the present invention.

FIG. 2 is a sectional view taken along line AA of the embodiment of FIG.

FIG. 3 shows another embodiment of the acceleration responsive switch of the present invention.

FIG. 4 is a sectional view taken along line CC of the embodiment of FIG. 3;

FIG. 5 is an example of an abutment member used in the embodiment of FIGS. 3 and 4;

FIG. 6 is a cross-sectional view of an example of the housing of the acceleration responsive switch of the present invention.

FIG. 7 shows an embodiment of a seismic sensor using the acceleration response switch of the present invention.

[Explanation of symbols]

 1, 21: acceleration response switch 2: lid plate 3: lead terminal 4: electrically insulating filler 5, 23, 35: housing 5C: protrusion (contact portion) 6: contact member 7: inertial ball 8: protective plate 9 : Damping liquid 22: Contact member 22B, 35A: Contact part

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hideki Koseki 4-30-30 Hoshocho, Minami-ku, Nagoya-shi Examiner in Ikukata Manufacturing Co., Ltd. Hiroyuki Kikui (56) References JP-A-61-239191 (JP, A) JP-A-63-263423 (JP, A) JP-A-2-147825 (JP, A) Japanese Utility Model Laid-open No. 52-144784 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01H 1/00

Claims (3)

(57) [Claims] 1. A cover plate in which a conductive lead terminal is passed through a hole formed substantially in the center of a substantially circular metal plate through an electrically insulating filler and hermetically fixed, and a bottomed cylindrical conductive housing is provided. The bottom surface of the housing is formed with an inclined surface that gradually rises concentrically and gradually from the center to the outside, and the open end of the housing is air-tightly fixed to the peripheral edge of the lid plate to seal the closed container. A contact made of a conductive material having a plurality of pliable elastic wing-shaped portions formed and arranged with contact portions substantially concentrically around a conductive terminal pin at the end of the lead terminal inside the container of the lid plate. The member is conductively fixed, and a conductive solid inertial sphere is housed in the closed container so as to be located at the approximate center of the bottom surface of the housing by gravity when stationary in a normal posture, and the inertia is generated by receiving vibration. The ball rolls The wing-shaped portion is displaced and slid while being in contact with the point member, and is simultaneously short-circuited between the inner surface of the housing and the contact member via an inertial sphere, and the inertial sphere is stationary on the inner surface of the housing. Sometimes an irrelevant contact portion is provided on a wall portion that contacts when receiving a predetermined acceleration, and the inertial sphere intermittently contacts the contact portion when a rotational force is applied along the inner wall of the housing. The path is changed so that the contact between the inertial sphere and the contact member is discontinuously disturbed, and in the closed container , at least a minimum operating temperature range is set in order to suppress undesired rolling of the inertial sphere. Viscosity even at temperature
The temperature of the damping liquid selected so that
Does not cause deformation of closed container due to expansion and contraction due to change
The acceleration responsive switch , wherein a predetermined amount of the gas is injected and a gas is present on the free surface . 2. The injection amount of the damping liquid is from 1/4 of the inertial sphere.
The acceleration responsive switch according to claim 1, wherein the amount is an amount covering the whole . 3. The vibration damping liquid is a fluorine inert liquid.
The acceleration responsive switch according to claim 1 or 2, wherein: