JP3258412B2 - Seismograph - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismometer, and more particularly to a case forming an outer shell, a magnetic circuit formed in the case and forming an annular gap through which lines of magnetic force pass, and a supporting spring member in the case. And a coil fixed to the vibrator and located in the gap of the magnetic circuit and vibrating in the gap with the vibration of the vibrator and crossing the magnetic field lines.

[0002]

2. Description of the Related Art Conventionally, there are the following seismometers. The seismometer 30 is of a moving coil type, and has a cylindrical case 31 with a bottom as shown in FIG.
A magnetic circuit composed of a permanent magnet 32 and yokes 33 and 34 is formed therein. An annular gap 35 is formed in the magnetic circuit so that the lines of magnetic force intersect with each other. Supported by a supporting spring member 37 so as to vibrate at the natural frequency of the above, and a coil 38 located in the annular gap 35 is attached to the vibrator 36. It is supposed to be taken out. In this example, the permanent magnet 3
2 and the yokes 33 and 34 are two magnetic circuits.
They are provided symmetrically via a spacer 40 as a set.

When the seismometer 30 vibrates in a state where the seismometer is installed, the vibrator 36 vibrates relative to the case 31 in the axial direction, and the coil 38 provided on the vibrator 36 has an annular shape. An electromotive force is generated across the magnetic field lines of the gap 35. Thereby, an alternating signal according to the vibration can be obtained, and the measurement of the seismic wave can be performed.

[0004]

In recent years, when exploring a place where an observer such as a volcano cannot reach or a celestial body other than the earth such as a moon or a planet, a seismometer is placed at the place or celestial body. Then, the vibration generated at the place and the surface of the celestial body (this vibration is called “earthquake” and the device that measures this vibration is called “seismometer” is not always accurate. And the vibration of the explosive when it explodes is detected, and the geological structure and celestial structure at the location are analyzed.

[0005] As a seismometer for detecting such a seismic wave, a high-sensitivity seismometer that can detect even a minute vibration is required. Therefore, such a seismometer has a precise structure. On the other hand, such a seismometer is transported from the earth (observation location) to a target celestial body (location) by a means of transport such as a rocket or an airplane, and installed. For installation of this seismometer, it is conceivable to carry out a soft landing on the celestial body or the place where the vehicle with the seismometer is loaded.However, in general, the penetrator loaded with the seismometer is transported by this penetrator. It is to be installed by impacting the celestial body or the relevant location from the transport means.

In such a case, when the penetrator penetrates into the celestial body, an extremely large acceleration (for example, an acceleration exceeding 10,000 G) is applied to the seismometer. Therefore, seismometers used for such a purpose must satisfy the conflicting demands that they must be able to withstand large shock accelerations and also detect minute vibrations.

Therefore, in such a special seismograph, it is conceivable to surround the entire instrument with a protective body or to hold the vibration system with a protective body such as elastic rubber. According to the applicant's experiments, it has been found that the performance cannot be ensured for the following reasons. This is because the elastic body such as rubber cannot maintain its elasticity in the extreme state, that is, in the state where the large acceleration is applied as described above.

[0008] Therefore, the present invention is to withstand a strong impact acceleration at the time of installation, at a place where an observer cannot directly install an observing instrument (seismometer), such as an astronomical object or a volcano, and to install a micrometer after installation. It is an object of the present invention to provide a seismometer capable of detecting various vibrations.

[0009]

In the present invention, the first means for solving the above-mentioned problems is, as shown in FIG. 1, a case 2 forming an outer shell, and a case 2 formed in the case 2; A magnetic circuit 4 forming an annular gap 3 through which lines of magnetic force pass, a vibrator 6 supported by a support spring member 5 in the case 2, and fixed to the vibrator 6 and located in the annular gap 3 of the magnetic circuit 4. In a seismometer provided with a coil 7 vibrating in the gap along the vibration of the vibrator 6 and crossing the magnetic field lines, an amplitude suppressing means 8 for prohibiting movement of the vibrator 6 with a predetermined amplitude or more, and supporting the vibrator 6 And a supporting spring deformation suppressing means 9 for inhibiting deformation of the supporting spring member 5 by a predetermined amount or more.

In a second aspect of the present invention, the vibration suppressing means 8 includes a vibration direction vibration suppressing means 10 for prohibiting vibration of the vibrator 6 with a predetermined amplitude or more in an earthquake detecting direction; The vibration orthogonal direction vibration suppressing means 11 prohibits vibration having a predetermined amplitude or more in a direction perpendicular to the direction. Further, according to a third aspect of the present invention, the vibration suppressing means 8 includes a rotation suppressing means 12 for inhibiting rotation of the vibrator at a predetermined angle or more.

[0011]

According to the first means of the present invention, unnecessary movement of the vibrator and deformation of the supporting spring member when the seismometer is installed are suppressed, so that the seismometer is installed with an external impact. Even if the seismograph is not damaged, the seismometer can be used normally and the seismic wave at the installation location can be measured thereafter.

According to the second means of the present invention, unnecessary movement of the vibrator in the vibrating direction at the seismometer installation site is prevented by the vibrating direction vibration suppressing means which is the vibration suppressing means. The movement in the vibration orthogonal direction is suppressed by the vibration orthogonal direction vibration suppression means. Further, according to the third means of the present invention, unnecessary rotation of the vibrator when the seismometer is installed is suppressed by the rotation suppressing means.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show an embodiment of a seismometer according to the present invention. At the time of actual measurement, three seismometers are installed on the gimbal so as to be orthogonal to each other, and the seismometer uses the gravity of the celestial body and is fixed in the vertical direction of the celestial body and in two horizontal directions. It is supposed to be. These seismometers are installed on a target celestial body together with a detected signal amplifier, a transmitter, and the like, and the detected vibration of the earthquake is transmitted to the earth or an artificial celestial body as a relay means.

In this embodiment, as shown in FIG. 1, the seismometer 1 includes an annular permanent magnet 13 in a bottomed cylindrical case 2 made of a nonmagnetic metal such as aluminum or titanium. And two annular yokes 14 and 15 connected to both poles of the permanent magnet 13 to form the magnetic circuit 4,
An annular gap 3 having an opening in the axial direction of the case 2 is formed between the two yokes 14 and 15.
Are crossed by lines of magnetic force formed by the magnetic circuit 4. In the present embodiment, as in the conventional example, the magnetic circuit composed of the permanent magnet 13 and the yokes 14 and 15 is provided symmetrically via the spacer 19 as a set of two magnetic circuits.

In this embodiment, a substantially cylindrical vibrator 6 made of the same metal as the case 2 is vibrated inside the case 2 at a predetermined natural frequency along the axis of the case 2. The vibrator 6 is supported by a supporting spring member 5 and a coil 7 located in the annular gap 3 is attached to the vibrator 6. In this embodiment, two sets of the support spring members 5 are used at both ends of the vibrator 6, and two sets are used. The ends are connected and fixed to the vibrator 6.

In this embodiment, as shown in FIG. 1, the case 2 is provided with a screw-in type axial stopper 16 as amplitude-direction vibration suppressing means for restricting unnecessary movement of the vibrator when the seismometer is installed. Is provided to limit the movement of the vibrator 6 in the vibration direction (biaxial direction of the case). Further, the vibrator 6 is provided with a protruding portion 17 outward, and has a predetermined size between the yoke 15 and the yoke 15. Coil 7 and each yoke 14,1
A gap having a size smaller than the size between the first and fifth vibrations is provided so as to prevent the vibrator 6 from moving in a direction perpendicular to the axis over a predetermined size or more as vibration orthogonal direction vibration suppressing means.

The axial stopper 16 is screwed until it once comes into contact with the vibrator 6, and is rewound a predetermined number of times so as to be spaced apart from the vibrator by a predetermined size and fixed with a nut 18. Is done. In this embodiment, a groove 9 is provided as an amplitude suppressing means (supporting spring deformation suppressing means) in a mounting portion of the supporting spring member 5 to the case 2, and both ends of the vibrator 6 are provided with an edge. Is provided with a protruding portion 6a that protrudes outward until it comes close to the inner surface of the case, and connects and fixes the support spring member 5. Even when the support spring receives an impact acceleration when the seismometer is installed, It comes into contact with the inner wall of the groove 9 and does not deform any more.

Further, in the present embodiment, as shown in FIGS. 2 and 3, the case is provided with a protrusion 20 protruding inward, and the protrusion 6a of the vibrator 6 is slightly more than the protrusion 20. A groove 21 having a wide width (dimension in the direction of the arc) into which the above-mentioned projection is inserted is formed so that the vibrator 6 does not rotate. In each of the drawings, reference numeral 22 denotes a lead wire for taking out the signal of the coil to the outside of the seismometer.

Therefore, according to the present embodiment, when the seismometer 1 is installed, even if a large impact acceleration is applied to the seismometer 1, unnecessary movement of the vibrator 6 in the vibration direction is prevented by the vibrator 6 having the axial stopper. By contact with the vibrator 6, the movement of the vibrator 6 in the vibration orthogonal direction is
Is suppressed by contact with the yoke 15. Unnecessary rotation of the vibrator 6 when the seismometer is installed
The protrusion 20 of the case 2 is suppressed by contacting the inner wall of the groove 21 of the vibrator 6, and the support spring member 5 is in contact with the inner wall of the groove 9 to prevent deformation.

[0020]

As described above, according to the present invention,
In the seismometer, an amplitude suppressing means for prohibiting movement of the vibrator with a predetermined amplitude or more and a supporting spring deformation suppressing means for prohibiting deformation of a supporting spring member supporting the vibrator by a predetermined amount or more are provided. Unnecessary movement of the child and deformation of the supporting spring member are suppressed, so that even if the seismometer is installed with an external impact, the seismometer will not be damaged, and the seismometer will be used normally afterwards. Therefore, it is possible to measure the seismic wave at the installation location.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a seismometer according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view corresponding to the line II-II in FIG. 1, showing a configuration of a seismometer according to the embodiment.

FIG. 3 is a cross-sectional view corresponding to line III-III in FIG. 2, illustrating a configuration of a seismometer according to the embodiment.

FIG. 4 is a cross-sectional view corresponding to FIG. 1 showing a configuration of a conventional seismometer.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 seismometer 2 case 3 annular gap 4 magnetic circuit 5 support spring member 6 vibrator 7 coil 8 amplitude suppression means 9 support spring deformation suppression means 10 vibration direction vibration suppression means 11 vibration orthogonal direction vibration suppression means 12 rotation suppression means

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01H 1/00 G01H 11/02

Claims (3)

(57) [Claims] 1. A case (2) forming an outer shell, a magnetic circuit (4) provided in the case (2) and forming an annular gap (3) through which lines of magnetic force pass, and a case (2). A vibrator (6) supported by a supporting spring member (5); and a vibrator (6) which is fixed to the vibrator (6) and located in an annular gap (3) of the magnetic circuit (4). In a seismometer provided with a coil (7) vibrating in the gap (3) and crossing the magnetic field lines, an amplitude suppressing means (8) for inhibiting movement of the vibrator (6) with a predetermined amplitude or more; 6. A seismograph comprising a support spring deformation suppressing means (9) for inhibiting deformation of the support spring member (5) for supporting 6) by a predetermined amount or more. 2. The vibrator (6), wherein said amplitude suppressing means (8) comprises:
A vibration direction vibration suppressing means (10) for prohibiting vibration of a predetermined amplitude or more in the earthquake detection direction, and a vibration orthogonal direction vibration suppressing means (11) for prohibiting vibration of a predetermined amplitude or more in a direction perpendicular to the earthquake detection direction of the vibrator. 2. The seismometer according to claim 1, wherein 3. The seismometer according to claim 1, wherein said amplitude suppressing means includes rotation suppressing means for prohibiting rotation of the vibrator at a predetermined angle or more.