JP2578291B2 - Linear motor type seismic source - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Industrial application field] Observation of elastic waves (S-waves) generated at arbitrary locations on the ground at multiple points, and analysis of the observed waveforms to analyze the depth, geology, etc. The present invention relates to a linear motor type elastic wave exploration source for generating an elastic wave (S wave) used for investigating a structure.

[0002]

2. Description of the Related Art Many techniques have been provided for an epicenter that independently generates an S-wave, and a plate hitting method is widely used.

In the hitting method, a plate is placed on the ground surface, an appropriate load is applied on the plate, and an impact force is applied to the plate by hitting the edge of the plate with a mallet or the like using human power or mechanical power. The elastic wave (S wave) is generated by transmitting the force to the ground. The hitting method includes the use of a spring hammer, an electromagnetic hammer, a hydraulic hammer, an S-wave cannon, and the like, which strikes with a hanging arrow by human power and causes the weight pendulum to fall by manual power.

[0004] There is also a surface explosion method in which an explosive is exploded directly on the ground surface to extract and measure an S-wave component from the generated waves.

In the conventional plate hitting method, (a) the applied force is limited by human power, and the propagation distance of the elastic wave is limited. ◎ (b) There is no reproducibility of the generated waves because there is no reproducibility of the impact force with human power. (C) Since the collision phenomenon is used, there is no reproducibility of the generated waves. (D) The size, shape and frequency of generated waves cannot be controlled. (E) Waves other than a single pulse cannot be emitted. (F) It is difficult to accurately synchronize elastic waves into the ground from multiple points. (G) The wear of the device is large due to the collision part. There are problems such as.

In addition, S wave cannons and surface explosions are dangerous because (a) explosives are used. (B) Generates noise. (C) The above makes it difficult to use in urban areas. (D) There is no reproducibility of generated waves. (E) The size, shape and frequency of generated waves cannot be controlled. (F) Waves other than a single pulse cannot be emitted. (G) Since preparation is troublesome, it is difficult to repeatedly generate an elastic wave. There are problems such as.

An electromagnetic vibration device for civil engineering is well known, and is disclosed in, for example, Japanese Patent Application Laid-Open No. 63-24185. However, such a known technique is to drop a reaction mass body, and a vibration having a different waveform is generated each time the reaction mass body is dropped. Japanese Patent Application Laid-Open No. 63-50783 discloses a technique for generating various S waves by using a hydraulic actuator or a gear. However, such a known technique has a complicated structure, has a problem in waveform reproducibility, and may cause an unintended waveform by a mechanical device.

Further, US Pat. No. 3,993,0034 discloses an underwater acoustic detector which is formed in a helical shape and uses a magnetic circuit yoke. However, such techniques cannot generate elastic waves for use in geological surveys.

[0009]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a linear motor type elastic wave exploration seismic source which can generate an arbitrary reproducible source waveform with high accuracy and with a simple device.

[0010]

According to the linear motor type elastic wave exploration seismic source of the present invention, flat linear motors that move linearly are arranged to face each other and the primary side and the secondary side that move relative to each other. The primary side is connected to a structure for installation on the ground, the secondary side is provided with a movable mass, and the primary side is provided with a drive coil, and the secondary side is provided with a permanent magnet. The primary side and the secondary side are mutually supported by a supporting machine.

According to the linear motor type elastic wave exploration seismic source of the present invention, there is provided a cylindrical linear motor having an inner side and an outer side which move relative to each other, one of the inner side and the outer side is a primary side, and the other is a primary side. The secondary side, the primary side is connected to the structure for installation on the ground, the movable side is provided on the secondary side, and the drive coil is provided on the primary side, and the permanent magnet is provided on the secondary side. The primary side and the secondary side are mutually supported.

[0012]

[0013]

[0014]

[0015]

In operation, an electromagnetic force acts between the primary side and the secondary side of the linear motor, and relative movement occurs between the two. In the invention of claim 1, the relative movements are in the straight directions, and
In the invention of claim 2, the directions are shifted from each other. The force generated at this time is transmitted to the ground via a connection structure with the ground connected to the primary side, and generates an elastic wave (S wave) for geological investigation (elastic wave exploration). According to the first aspect of the present invention, since the primary side and the secondary side face each other, the support mechanism can be simplified. According to the second aspect of the present invention, the suction force can be offset, and a simple bearing can be used. In any of the inventions, the waveform is reproducible by using a linear motor, and the structure can be made extremely simple by allowing the primary side and the secondary side to move relative to each other.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a flat plate type linear motor B is provided in a vibrating unit generally denoted by reference numeral A. The primary side 10 of the motor B is connected to a structure for installation on the ground, that is, the ground plate 1, and the secondary side 20 has
A movable mass, that is, an upper plate 2 and a weight 3 are provided.
The upper plate 2 is supported by a leaf spring 4 which is a support mechanism interposed between the upper plate 2 and brackets 1a erected on both sides of the ground plate 1.

FIG. 2 shows the structure of the linear motor B. On the lower surface of the secondary side 20, a plurality of magnetic poles (four in the illustrated example) which are adjacent to each other in a direction perpendicular to the vibration direction and adjacent to each other are provided.
Are provided on the upper surface of the primary side 10 so as to face the permanent magnet 21.
1b is provided.

FIG. 3 shows another embodiment of the support mechanism, in which four corners of the upper plate 2 of the vibration unit A1 are supported on the ground plate 1 by the laminated spring 5.

FIG. 4 shows another embodiment of the support mechanism, in which the upper plate 2 of the vibration unit A2 is supported on the ground plate 1A by two pairs of bearings 6.

FIGS. 5 and 6 show another embodiment of the present invention, in which the secondary side yoke 20a of the linear motor B1 of the vibration unit A3 is formed in a U-shape, and the primary side 10a is provided inside thereof. Is an example in which. On the upper and lower surfaces of the secondary side 20a, permanent magnets 21a and 21b having different magnetic poles are provided.
Drive coils 11a and 11b are provided on the primary side 10a.

In the case of this embodiment, the primary side 10a and the secondary side 2
0a, the magnetic attraction force acting during 0a is offset, so the primary side 1
Oa and the secondary side 20a can simplify the structure of the mutual support mechanism.

FIGS. 7 to 10 show another embodiment of the present invention, in which cylindrical linear motors B2 and B3 are used for vibrating heads A4 and A5. In the example of FIG. 7, the outside, that is, the primary side 10b is connected to the ground plate 1, and the inside is the secondary side 20b. In FIG. 10, the inside, that is, the primary side 10c is paired with the ground plate 1. Bracket 1b
In this example, the outside is a secondary side 20c.

FIGS. 8 and 11 show an example of a cylindrical linear motor, in which the inner and outer sides are supported by a pair of bearings 23 so as to be movable in the axial direction. 22b, and a permanent magnet 1 inside.
FIG. 11 shows an example in which drive coils 11a and 11b are provided on the inside and permanent magnets 21a and 2b are provided on the outside.
1b is provided. In the case of this cylindrical configuration, the suction force between the outside and the inside is canceled out and the force applied to the bearing 23 is reduced, so that a simple bearing such as a slide bearing can be used.

FIG. 12 shows acceleration (force), speed, displacement, and displacement to speed phase diagram of the linear motors B, B1 to B3 when driven by a half sine wave. 2 in the figure
The next side has a speed of 2 V when driving is completed, and continues to move. In order to stop this movement, it is necessary to generate a force opposite to the movement.

On the other hand, FIGS. 13 and 14 show movement waveforms in which the approaching sections are provided before and after the half sine wave. In this case, the speed difference before and after the generation of the impact force (section Tf in FIG. 13) is the same as that in section Tf in FIG. 12, but the speed changes from minus V to plus V. Therefore, the momentum changes of both are the same, but when the driving is completed,
The kinetic energy of the next side is reduced to 1/4, and the energy required for stopping the movement can be reduced, so that the power can be saved and the device can be made compact by shortening the stroke.

FIGS. 15 to 17 show a traveling type epicenter vehicle 30. The epicenter vehicle 30 has an epicenter 3
1. An epicenter control unit 34 and a power supply unit 35 are provided.
The hypocenter 31 is provided at the lower part of the vehicle body and includes a plurality (four in the illustrated example) of linear motor type hypocenters U1 to U4 composed of flat linear motors whose primary sides are connected to the ground plate 1. Ground plate 1 and pair of jacks 3 for grounding plate
2, a plurality of rollers 33 are interposed between the jack 32 and the ground plate 1.

FIG. 18 shows an example of an elastic wave exploration mode using this traveling type hypocenter vehicle 30. As shown in FIG. At the time of the exploration, one or a plurality of hypocenter vehicles 30 are arranged at a predetermined hypocenter location, a plurality of vibration sensors 36 are grounded at a predetermined location, and connected to a measurement system (amplifier, filter, recording device, etc.) not shown. . Some or all of the epicenter units U1 to U4 are operated with an appropriate waveform according to the purpose of the exploration, the hardness of the target ground, the noise characteristics of the surroundings, and the like. The ground vibrations at a plurality of points where the vibration sensor 36 is installed at the driving vibration time and before and after the driving vibration time are measured and recorded in the recording device of the measurement system. The measured waveform is analyzed by a computer, and the internal structure of the ground is investigated by extracting waves reflected or refracted at the boundary surface of the stratum.

FIGS. 19 and 20 show a control system of a traveling type epicenter vehicle 30 shown in FIGS. 15 to 18 as an example of a control system for synchronously operating a plurality of linear motor type epicenter units U1 to U4. It is a thing.

One epicenter vehicle 30 includes a plurality of linear motor type epicenter units U1 to U4 and each of these epicenter units U1 to U4.
Drive control circuit for each of .about.U4 and each drive control circuit C
It is composed of a control computer CO that sends operation control signals to 1 to C4. By transmitting an operation control signal synchronized with each drive control circuit from the control computer CO, a plurality of linear motor type epicenter units can be operated synchronously.

For the synchronous operation of each epicenter unit of the plurality of epicenter vehicles 30, the control computer CO of each epicenter vehicle is synchronized to send a synchronized operation control signal to each of the drive control circuits C1 to C4 of each epicenter vehicle 30 ( 19) or by sending operation control signals synchronized with the respective drive control circuits C1 to C4 of the plurality of epicenter vehicles 30 directly from the control computer CO of the specific epicenter vehicle 30 (FIG. 20).

[0032]

Since the present invention is configured as described above, it has the following effects.

(1) There is reproducibility of the epicenter waveform. (2) Elastic waves can be generated repeatedly over a short period of time. (3) It is possible to output any frequency and any shape of source waveform. (4) No unintended unnecessary wave components are generated. (5) A plurality of devices can be operated synchronously and in parallel. (6) Therefore, a larger elastic wave can be generated. (7) Further, it is possible to control the waves from a plurality of points and send the waves underground. (8) With the above combination, it is possible to generate the most suitable epicenter waveform according to the characteristics of the ground to be surveyed and the purpose of the survey. (9) Since the collision phenomenon is not used, the reliability and durability of the device are high, and no noise is generated. (10) By using this device, it is possible to save labor and automate the epicenter.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a side view showing the motor of FIG. 1;

FIG. 3 is a perspective view showing another embodiment of the support mechanism.

FIG. 4 is a perspective view showing another embodiment of the support mechanism.

FIG. 5 is a perspective view showing a second embodiment of the present invention.

FIG. 6 is a side view showing the motor of FIG. 5;

FIG. 7 is a side view showing a third embodiment of the present invention.

FIG. 8 is a side sectional view showing the motor of FIG. 7 or 10;

FIG. 9 is a front sectional view of FIG. 8;

FIG. 10 is a side view showing a fourth embodiment of the present invention.

FIG. 11 is a side sectional view showing the motor of FIG. 7 or 10;

FIG. 12 is an acceleration, velocity, displacement, and displacement-velocity phase diagram when the linear motor is driven.

FIG. 13 is a drawing showing an example of a motion waveform of the occurrence of an impact.

FIG. 14 is a displacement / velocity phase plane transition diagram of FIG. 13;

FIG. 15 is a side view showing an epicenter vehicle.

FIG. 16 is an enlarged view of the epicenter in FIG. 15;

FIG. 17 is a front view of FIG. 16;

FIG. 18 is a perspective view illustrating a mode of exploration.

FIG. 19 is a block diagram illustrating an example of a mode of transmitting a driving control signal synchronized with each driving control circuit of a plurality of hypocenter vehicles.

FIG. 20 is a block diagram showing an example different from FIG. 19;

[Explanation of symbols]

 A, A1 to A5: Exciting unit B, B1: Flat plate linear motor B2, B3: Cylindrical linear motor CO .... Control computer C1 to C4: Drive control circuit U1 to U4 ... Linear motor type hypocenter unit 1, 1A ... Ground plate 1a, 1b ... Bracket 2 ... Upper plate 3 ... Weight 4 ... Leaf spring 5 ... Laminated spring 6 ... · Bearings 10, 10a to 10c ··· Primary side 11a, 11b, 22a and 22b ··· Driving coils 12a, 12b, 21a and 21b ··· Permanent magnets 20, 20a to 20c ··· Secondary side 23 ·・ ・ Bearing 30 ・ ・ ・ Earthquake car 31 ・ ・ ・ Earthquake part 32 ・ ・ ・ Jack 33 ・ ・ ・ Roller 34 ・ ・ ・ Earthquake control part 35 ・ ・ ・ Power supply part 36 ・ ・ ・ Vibration sensor

Continued on the front page (72) Inventor Shinji Furuya 2-9-1-1, Tobita-Ki, Chofu-shi, Tokyo Kashima Construction Co., Ltd. (72) Inventor Fumio Kinoshita 191-1, 2-2-1, Tobita-Kibito, Chofu-shi, Tokyo Kashima Construction Research Institute (72) Inventor Hiroaki Yamanaka 1-2-7 Moto-Akasaka, Minato-ku, Tokyo Kashima Construction Corporation (72) Inventor Toshihiko Watanabe 5-36-11 Shimbashi, Minato-ku, Tokyo Fujiden Inside Kaichi Kagaku Co., Ltd. (72) Inventor Kazutaka Honma 5-36-11 Shimbashi, Minato-ku, Tokyo Fuji Denki Kagaku Co., Ltd. 1 Kikuna Sky Mansion A709 (56) Reference JP-A-63-24185 (JP, A) JP-A-63-50783 (JP, A) US Patent 3990034 (US, A)

Claims (2)

(57) [Claims] A flat linear motor that moves linearly has a primary side and a secondary side that are arranged to face each other and that move relative to each other, and the primary side is connected to a structure for installation on the ground. A movable mass is provided on the secondary side, a driving coil is provided on the primary side, a permanent magnet is provided on the secondary side, and the primary side and the secondary side are mutually supported by a supporting machine. A linear motor type elastic wave exploration epicenter characterized by: 2. A motor comprising a cylindrical linear motor having an inner side and an outer side which move relative to each other, one of the inner side and the outer side being a primary side, the other being a secondary side, and the primary side being installed on the ground. A movable mass is provided on the secondary side, and a drive coil is provided on the primary side.
A linear motor type elastic wave exploration seismic source characterized in that a permanent magnet is provided on the secondary side and the primary side and the secondary side are supported by each other.