JP4653909B2 - Electrodynamic detector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrodynamic detector, and more particularly to an electrodynamic detector suitable for use in observing a place where an observer cannot directly go.
[0002]
[Prior art]
The electrodynamic detector detects the movement of the object under measurement using the principle that when a conductor moves in a magnetic field, an induced electromotive force is generated in the conductor in proportion to the speed of the movement. To do. Specifically, for example, an electrodynamic detector includes a movable body that is elastically supported so as to be freely displaced in accordance with the movement of the measured object, a coil as a conductor attached to the movable body, And a magnetic circuit that applies a magnetic field, and is configured to output an induced electromotive force generated in the coil when the movable body is displaced.
Such an electrodynamic detector is used, for example, for observing volcanic activity. In this case, since the observer cannot enter the observation location, the penetrator on which the electrodynamic detector is placed is dropped from the sky using a helicopter or the like, and driven into the ground surface. A type detector is installed.
[0003]
By the way, because of the strong impact acceleration applied to the electrodynamic detector at the time of driving, it is preferable that the electrodynamic detector used for observing the place where the observer cannot directly go is shock resistant. . From this point of view, as disclosed in, for example, Japanese Patent Application Laid-Open No. 6-235656, the applicant has been provided with a stopper that prevents the movable body from being displaced by a predetermined amplitude or more. According to this electrodynamic detector, even if a strong impact acceleration is applied at the time of driving, the movable body does not collide with the inner surface of the main body case, so that the movable body is prevented from being damaged.
[0004]
[Problems to be solved by the invention]
However, in the electrodynamic detector disclosed in Japanese Patent Laid-Open No. 6-235656, the movable body can be prevented from being damaged, but the coil attached to the movable body may be disconnected. In this case, no output can be obtained from the electrodynamic detector.
The present invention has been made in view of such circumstances, and an object thereof is to provide an electrodynamic detector with higher reliability.
[0005]
[Means for Solving the Problems]
The electrodynamic detector of the present invention that achieves the above object includes, as shown in FIG. 1, for example, a plurality of coils (4a, 4b) and magnetic field generating means (for example, a magnetic circuit) for applying a magnetic field to each of the coils. 5, 6, etc.), each coil is arranged, and a movable body (3) configured to displace each coil in the magnetic field according to the movement of the measured object, and induction induced in each coil Output type means for outputting an electromotive force (for example, output terminals 13, 14), wherein the coils are connected in parallel, and the output means is connected to the parallel connected coils. Configured to output an induced electromotive force ,
A through hole is formed in the movable body,
One end of a plurality of wires for connecting the coils in parallel to the through hole is passed through a wire connected to the start or end of a predetermined coil.
Provided in the movable body a relay terminal that aggregates wiring connected to a starting end or a terminal end of a coil other than the predetermined coil among the plurality of wirings and wiring passed through the through hole,
The relay terminal and the output means are connected to each other.
[0006]
Here, the magnetic field generating means is not particularly limited as long as it generates a magnetic field. For example, a permanent magnet, an electromagnet, iron or other magnetic material magnetized by these, or a magnetic circuit formed by combining these, or the like. Can be used.
[0007]
In this case, it is preferable that a substantially equal induced electromotive force is induced in each of the coils.
[0008]
Specifically, the coil lengths of the coils are made substantially uniform, and the magnetic field generating means applies a magnetic field having a substantially equal magnetic flux density to the coils, so that all the coils receive the magnetic field. It may be configured to displace at a substantially equal speed in a direction substantially perpendicular to the magnetizing direction.
[0009]
In any case, it is preferable that through holes (33a, 33b) are formed in the movable body, and wirings for connecting the coils in parallel are passed through the through holes.
[0010]
According to the electrodynamic detector of the present invention, a magnetic field is applied to each of the plurality of coils by the magnetic field generating means. When the measured object moves, each coil is displaced in the magnetic field according to the movement of the measured object. As a result, a Lorentz force corresponding to the movement of the measurement object acts on the electric charge in each coil. Therefore, an induced electromotive force corresponding to the movement of the measured object is generated in each coil. In addition, since the coils are connected in parallel and the induced electromotive force induced in the parallel-connected coils is output by the output means, it is assumed that some coils are temporarily disconnected due to impact at the time of driving. However, if at least one of the coils is not disconnected, a voltage corresponding to the movement of the measured object is output from all of these coils. Therefore, even if some of the plurality of coils are disconnected, the movement of the measured object can be continuously observed, and the reliability of the electrodynamic detector can be improved.
[0011]
In addition, according to the electrodynamic detector of the present invention, when the object to be measured moves, substantially the same induced electromotive force is induced in all the coils, so that there is no potential difference between the coils and the coils are connected in parallel. The coils do not load each other. Therefore, even when all the coils are normally connected in parallel, or even when some coils are disconnected due to impact at the time of driving, these coils are A voltage substantially equal to the induced electromotive force induced in the coil is output. Therefore, the reliability of the electrodynamic detector can be further improved.
[0012]
In addition, according to the electrodynamic detector of the present invention, the coil lengths of all the coils are made substantially uniform, the magnetic field generating means gives a magnetic field having a substantially equal magnetic flux density to each of the coils, and all the coils are magnetic fields. Therefore, when the object to be measured moves, substantially the same induced electromotive force is induced in all the coils. The value of this induced electromotive force is given by the following equation.
E = BLV
Here, E represents the induced electromotive force, B represents the magnetic flux density, L represents the coil length, and V represents the relative speed of the coil.
Therefore, even when all the coils are normally connected in parallel, or even when some coils are disconnected due to impact at the time of driving, these coils are A voltage substantially equal to the induced electromotive force E induced in the coil is output.
Thereby, the reliability of an electrodynamic detector can be improved reliably.
[0013]
In addition, according to the electrodynamic detector of the present invention, the wiring in which one end of the wiring for connecting the coils in parallel to the through hole formed in the movable body is connected to the starting end or the terminal end of the predetermined coil. Since it is made to pass, it can be avoided that the magnetic field generating means etc. come into contact with the wiring due to the impact at the time of driving. Therefore, the wiring is not easily disconnected, and the reliability of the electrodynamic detector can be improved.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
First, the configuration of an electrodynamic speed pickup to which the present invention is applied will be described.
FIG. 1 is a schematic longitudinal sectional view of an electrodynamic speed pickup according to an embodiment. As shown in the figure, the main part of the electrodynamic speed pickup 100 is covered with a bottomed cylindrical casing 1 constituting an outer shell. A movable body 3 is constrained on the inner peripheral surface of the housing 1 so as to be displaceable in the vertical direction in FIG. 1 via support springs 2a and 2b as elastic support members. Two coils 4a and 4b connected in parallel with each other are wound around the movable body 3 in two upper and lower stages. The coils 4a and 4b are surrounded by magnetic circuits 5 and 6 as magnetic field generating means, respectively. These magnetic circuits 5 and 6 are fixed to the inner peripheral surface of the housing 1 in two upper and lower stages.
[0015]
The magnetic circuit 5 attached to the upper stage applies a magnetic field to the coil 4a wound on the upper stage of the movable body 3, and includes an L-shaped magnetic body 51 and an I-shaped magnetic body 52, A permanent magnet 53 that magnetizes the magnetic bodies 51 and 52 is constituted.
The magnetic body 51 is disposed in the center of the housing 1 and extends in the vertical direction in FIG. 1. The magnetic body 51 extends from the lower surface of the cylindrical portion 51 a to the inner peripheral surface of the housing 1. And a flange portion 51b protruding in a hook shape. A ring-shaped permanent magnet 53 having a rectangular cross section is attached to the peripheral portion of the upper surface of the flange portion 51b. On the upper surface of the permanent magnet 53, a ring-shaped magnetic body 52 having substantially the same outer diameter is attached.
[0016]
Further, a substantially cylindrical gap portion G1 is formed between the outer peripheral surface of the cylindrical portion 51a and the inner peripheral surface of the magnetic body 52. A static equal magnetic field is formed in the gap G <b> 1 by the magnetic body 51 attached to one magnetic pole of the permanent magnet 53 and the magnetic body 52 attached to the other magnetic pole of the permanent magnet 53. A coil 4a wound around the upper stage of the movable body 3 is loosely fitted in the substantially cylindrical gap G1 in which the static magnetic field is formed. And the magnetic flux of a static magnetic field has penetrated this coil 4a in the said radial direction, ie, the direction substantially perpendicular | vertical with respect to the winding direction of the conducting wire which comprises the said coil 4a.
[0017]
The magnetic circuit 6 attached to the lower side applies a magnetic field to the coil 4b wound on the lower stage of the movable body 3, and includes an L-shaped magnetic body 61 and an I-shaped magnetic body 62, The magnetic bodies 61 and 62 are composed of permanent magnets 63 that magnetize them.
The magnetic body 61 is disposed so as to overlap with the cylindrical portion 51a in plan view, and extends in the vertical direction in FIG. 1. The magnetic body 61 extends from the upper surface of the cylindrical portion 61a to the inner wall of the housing 1. And a flange portion 61b projecting in a bowl shape. The flange 61b and the flange 51b are adjacent to each other. And the ring-shaped permanent magnet 63 which has a rectangular cross section is contact | attached to the peripheral part of the lower surface of the collar part 61b. A ring-shaped magnetic body 62 having substantially the same outer diameter is attached to the lower surface of the permanent magnet 63.
[0018]
A substantially cylindrical gap G2 is formed between the outer peripheral surface of the cylindrical portion 61a and the inner peripheral surface of the magnetic body 62. In the gap G2, a static equal magnetic field is formed by the magnetic body 61 attached to one magnetic pole of the permanent magnet 63 and the magnetic body 62 attached to the other magnetic pole of the permanent magnet 63. A coil 4b wound around the lower stage of the movable body 3 is loosely fitted in the substantially cylindrical gap G2 in which the static magnetic field is formed. The magnetic flux of the static magnetic field penetrates the coil 4b in the radial direction, that is, in a direction substantially perpendicular to the winding direction of the conducting wire constituting the coil 4a.
[0019]
The magnetic forces of these permanent magnets 53 and 63 are substantially the same, and the characteristics of the magnetic circuits 5 and 6 are also substantially the same. Magnetic fields having substantially the same magnetic flux density are applied to the coils 4a and 4b, respectively. That is, magnetic fluxes having substantially the same density are magnetized in the coils 4a and 4b.
[0020]
Further, the coil 4a loosely fitted in the upper gap G1 and the coil 4b loosely fitted in the lower gap G2 have substantially the same coil length, and these are both attached to the integral movable body 3. It has been. The movable body 3 is elastically supported by support springs 2a and 2b such as annular diaphragm springs so as to be freely displaced in the vertical direction in FIG.
As a result, when the object to be measured moves, all the coils 4a and 4b penetrate the direction in which the magnetic field is magnetized, that is, the magnetic flux penetrates the magnetic circuits 5 and 6 fixedly attached to the inner wall of the housing 1. It is configured to be relatively displaced at a substantially equal speed in a direction (vertical direction in FIG. 1) substantially perpendicular to the direction and the winding direction of the coil, that is, the direction in which the electromotive force is generated.
[0021]
Moreover, the movable body 3 has coil bobbins 31 and 32 as coil winding portions disposed in two upper and lower stages, and a columnar main body portion 33 that integrally connects the coil bobbins 31 and 32. A coil 4 a and a coil 4 b are wound around the coil bobbins 31 and 32, respectively. These coil bobbins 31 and 32 are integrally connected by a main body portion 33.
[0022]
Among these, the first relay terminal 7 and the second relay terminal 8 are erected on the upper surface of the upper coil bobbin 31. The first relay terminal 7 is short-circuited to the start ends of all the coils 4a and 4b, and the second relay terminal 8 is short-circuited to the end ends of all the coils 4a and 4b.
Specifically, the first relay terminal 7 and the start ends of all the coils 4a and 4b are connected using individual wires, and the second relay terminal 8 and the end points of all the coils 4a and 4b. Are connected using separate wiring.
[0023]
More specifically, the coils are connected in parallel by connecting means configured to include wirings 9, 10, 11, and 12.
Among these, the wiring 9 has one end connected to the start end of the coil 4 a and the other end connected to the first relay terminal 7. The wiring 10 has one end connected to the start end of the coil 4 b and the other end connected to the first relay terminal 7.
The wiring 11 has one end connected to the terminal end of the coil 4 b and the other end connected to the second relay terminal 8. The wiring 12 has one end connected to the terminal end of the coil 4 a and the other end connected to the second relay terminal 8.
[0024]
The columnar main body 33 is formed with two through holes 33a and 33b communicating from one end to the other end along the longitudinal direction, and wirings 10 and 11 for connecting the coils in parallel are provided. The through holes are inserted. That is, the wiring 10 having one end connected to the start end of the coil 4 b is connected to the first relay terminal 7 through the through hole 33 a. In addition, the wiring 11 whose one end is short-circuited to the terminal end of the coil 4b is connected to the second relay terminal 8 through the through hole 33b.
[0025]
Further, the first relay terminal 7 and the second relay terminal 8 are respectively connected to the first output terminal 13 and the second output terminal as output means standing on the upper surface of the housing 1 by the wiring 15 and the wiring 16, respectively. It is connected to the output terminal 14. The terminals 13 and 14 output the induced electromotive force induced in the coils 4a and 4b connected in parallel. That is, by measuring the potential between the first output terminal 13 and the second output terminal 14, the induced electromotive force induced in each of the coils 4a and 4b can be measured.
[0026]
The operation of the electrodynamic speed pickup 100 configured as described above is as follows. When vibration is applied to the electrodynamic speed pickup 100 from a measurement object (not shown), the movable body 3 is elastically displaced in the vertical direction in FIG. 1 while being restrained by the support springs 2a and 2b. The object to be measured here corresponds to the earth or the like when observing the activity state of the volcano.
[0027]
Then, all the coils 4a and 4b attached to the movable body 3 are displaced in a direction substantially perpendicular to the direction in which the magnetic field is magnetized. As a result, Lorentz force corresponding to the speed of the object to be measured acts on the electric charges in the conducting wires constituting the coils 4a and 4b. Therefore, an induced electromotive force is generated in each of the coils 4a and 4b according to the movement of the measured object. The induced electromotive force induced in the coils 4a and 4b is expressed by the following equation (1).
[0028]
E = B × L × V × sin θ (1)
In Equation (1), E represents an induced electromotive force induced in the coil, B represents the magnetic flux density of the magnetic field generated by the magnetic circuit, and L represents the length of the conductive wire constituting the coil, that is, the coil length. V represents the relative velocity between the coil and the magnetic circuit, and θ represents the angle between the direction in which the coil is relatively displaced and the direction in which the magnetic flux is magnetized in the coil.
In this embodiment, since the magnetic circuits 5 and 6 are fixed and the coils 4a and 4b are displaced, the relative speed V is equivalent to the displacement speed of the coils 4a and 4b.
[0029]
Here, the coil lengths L of all the coils 4a and 4b are made substantially uniform, and the magnetic circuits 5 and 6 apply magnetic fields having substantially the same magnetic flux density B to the coils 4a and 4b, respectively. , 4b are configured to be relatively displaced at a substantially equal speed V in a direction (θ = π / 2 [rad]) substantially perpendicular to the direction in which the magnetic field is magnetized. When the body moves, an induced electromotive force E = B × L × V which is substantially equal to all the coils 4a and 4b is induced.
[0030]
Therefore, there is no potential difference between the coils 4a and 4b, and the coils 4a and 4b connected in parallel do not become loads. Therefore, a voltage substantially equal to the induced electromotive force E induced in each coil is output from the entire coils connected in parallel.
Then, the output voltage, that is, a signal representing the speed of the object to be measured is output to an external device (not shown) via the output terminals 13 and 14.
[0031]
Here, the external device refers to a measurement system device that receives an output from the electrodynamic speed pickup 100. The input impedance of the external device is designed to be sufficiently larger than the impedance of the electrodynamic speed pickup 100.
The impedance of the electrodynamic speed pickup 100 is approximately R / 2 when the two coils 4a and 4b are normally connected in parallel, and the impedance of each coil is R, and either coil is disconnected. If it is, it becomes R. Therefore, the input impedance of the external device is preferably designed to be at least R or more.
Then, the measurement results of the external device are collected in a center device (not shown) using, for example, microwaves or other radio waves.
[0032]
According to the electrodynamic speed pickup 100 described above, the following effects can be obtained.
(1) Since the coils 4a and 4b that generate substantially the same induced electromotive force E are connected in parallel to each other, even when the two coils are operating normally or due to an impact at the time of driving Even when one of the coils is disconnected, a voltage substantially equal to the induced electromotive force E induced in each coil is output from the entire coils. Therefore, even when one of the coils is disconnected, it is possible to continuously observe the speed of the measured object. Therefore, the reliability of the electrodynamic speed pickup 100 can be improved.
[0033]
(2) All the coils 4a and 4b are attached to the integral movable body 3 which is elastically supported so as to be freely displaced in accordance with the movement of the measurement object, and through holes 33a and 33b are formed in the movable body 3. In addition, since the wirings 10 and 11 for connecting the coils 4a and 4b in parallel are respectively passed through the through holes 33a and 33b, the coil arrangement structure can be rationalized. It is possible to avoid the magnetic circuits 5, 6 and the like coming into contact with the wirings 10, 11 due to the impact. Therefore, since the wiring is not easily disconnected, the reliability of the electrodynamic pickup 100 can be improved.
[0034]
(3) The movable body 3 is provided with the first relay terminal 7 and the second relay terminal 8, and the wirings 9, 10, 11, 12 for parallel connection are once aggregated to the terminals 7, 8, Since the terminals 7 and 8 and the output terminals 13 and 14 are connected by the wirings 15 and 16, respectively, the wirings that play along with the displacement of the movable body 3 are only the wirings 15 and 16. Therefore, it is possible to minimize the influence of the play of the wiring on the displacement of the movable body, so that accurate observation can be performed.
[0035]
The preferred embodiment of the present invention has been described above, but the technical idea of the present invention is not limited to this.
For example, the electrodynamic speed pickup 100 may be configured such that the induced electromotive forces induced in the coils 4a and 4b are different. That is, for example, the coil lengths of the coils 4a and 4b may be different. However, in this case, since the absolute value of the output voltage in the electrodynamic speed pickup 100 fluctuates after any of the coils is disconnected, the disconnected coil detection means for detecting which coil is disconnected, and this disconnection And a correction unit that corrects the output voltage value based on the detection result of the coil detection unit. Note that this correction means may be provided in the external device described above.
[0036]
Further, in addition to the coils 4a and 4b, a damping adjustment coil is further provided in the static magnetic field, and a desired damping is applied to the movable body 3 by the framing force generated by supplying a current to the damping adjustment coil. It may be given.
[0037]
The connecting means described above may further comprise switching means for switching the coils 4a and 4b to a state of being connected in parallel and a state of being connected in series. This switching means can be easily realized using switches and terminals.
In the state where the coils 4a and 4b are connected in series, the induced electromotive force output as the whole coil is the sum of the induced electromotive forces induced in the respective coils, so that the detection sensitivity can be improved. it can.
[0038]
Moreover, it is good also as providing three or more coils. In this case, the reliability can be further improved as compared with the case where two coils are mounted. Even when three or more coils are mounted, it is preferable to connect the start or end of each coil and the relay terminals 7 and 8 using individual wires. In this way, when the coils are connected in parallel, the number of wirings is increased as compared with the case where the wiring aggregation points are provided in the middle of the route, but even if one wiring is disconnected, it is sacrificed. Requires only one coil, and reliability can be improved reliably.
[0039]
【The invention's effect】
According to the present invention, even if some of the plurality of coils are disconnected, if any one of the coils is not disconnected, the observation of the movement of the measured object can be continued. The reliability of the vessel can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view showing a configuration of an electrodynamic speed pickup according to an embodiment.
[Explanation of symbols]
3 Movable bodies 4a, 4b Coils 5, 6 Magnetic circuit (magnetic field generating means)
13, 14 Output terminal (output means)
33a, 33b Through hole

Claims (3)

A plurality of coils;
Magnetic field generating means for applying a magnetic field to each of the coils;
A movable body configured to displace each coil in the magnetic field according to the movement of the body to be measured;
Output means for outputting an induced electromotive force induced in each coil, and a conductivity type detector comprising:
The coils are connected in parallel,
The output means is configured to output an induced electromotive force induced in the parallel connected coils ,
A through hole is formed in the movable body,
One end of a plurality of wires for connecting the coils in parallel to the through hole is passed through a wire connected to the start or end of a predetermined coil.
One end of the plurality of wires is provided with a relay terminal that aggregates the wires connected to the start end or the end of a coil other than the predetermined coil and the wires passed through the through holes, on the movable body,
An electrodynamic detector characterized in that the relay terminal and the output means are connected . The electrodynamic detector according to claim 1,
An electrodynamic detector characterized in that each coil is configured to induce substantially the same induced electromotive force. In the electrodynamic detector according to claim 2,
The coil length of each of the coils is substantially uniform,
The magnetic field generating means gives a magnetic field of substantially equal magnetic flux density to each coil,
An electrodynamic detector, wherein each coil is configured to be displaced at a substantially equal speed in a direction substantially perpendicular to a direction in which the magnetic field is magnetized.

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