Magnetic sensor and method of constructing the same

Abstract

To provide a magnetic sensor capable of sensing a minute current and a method of constructing the same.SOLUTION: A magnetic sensor is provided, comprising a cylindrical first hollow structure, a cylindrical first magnetic core provided inside the first hollow structure, a first multicore wire arranged in a cylinder axis direction within the first magnetic core, and a first winding coil wound around an outer periphery of the first hollow structure.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] FIELD The present disclosure relates to magnetic detectors and methods of constructing magnetic detectors. [Background technology]

[0002] As a magnetic detector, for example, a magnetic sensor disclosed in Patent Document 1 is known.

[0003] The magnetic sensor described in Patent Document 1 has an inner conductor and an outer conductor arranged coaxially and electrically connected together at one end, and a cylindrical core made of a soft magnetic material placed between these conductors. In this magnetic sensor, power is supplied between the outer conductor and the inner conductor from a high-frequency power supply, while a detection output voltage corresponding to the magnetic field to be measured is obtained from a detection coil wound around the outer periphery of the outer conductor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-330655 Summary of the Invention [Problem to be solved by the invention]

[0005] The magnetic sensor described in Patent Document 1 has a structure in which the internal conductor located at the center of the axis is simply covered with an insulating film, and therefore it may be difficult to detect minute currents.

[0006] It is an object of the present disclosure to provide a magnetic detector and a method for constructing a magnetic detector that overcomes the above-mentioned problems. [Means for solving the problem]

[0007] A magnetic detector according to one aspect of the present disclosure comprises a cylindrical first hollow structure, a cylindrical first magnetic core installed within the first hollow structure, a first multi-core wire installed within the first magnetic core in the cylindrical axis direction, and a first winding coil wound around the outer periphery of the first hollow structure.

[0008] A method for constructing a magnetic detector according to one aspect of the present disclosure includes placing a cylindrical magnetic core inside the hollow structure, placing a multi-core wire in the cylindrical axis direction inside the magnetic core, and winding a winding coil around the outer periphery of the hollow structure. [Effects of the Invention]

[0009] According to the above aspect, minute currents can be easily detected. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of a magnetic detector according to the present disclosure; [Figure 2] 1 is a schematic diagram of a magnetic detector according to the present disclosure; [Figure 3] FIG. 3 is a cross-sectional view showing the internal configuration of the magnetic detector of FIG. 2. [Figure 4] 1 is a schematic diagram of a magnetic detector according to the present disclosure; [Figure 5] 1 is a schematic diagram of a magnetic detector according to the present disclosure; [Figure 6] 1A-1C are process diagrams illustrating a method for constructing a magnetic detector according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] Each embodiment will be described below with reference to the drawings. In all drawings, the same or corresponding components are designated by the same reference numerals, and common descriptions will be omitted. It should be noted that in this disclosure, the drawings may relate to one or more embodiments.

[0012] First Embodiment Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. As shown in FIG. 1, the magnetic detector 100 includes a cylindrical molded core (first magnetic core) 11, a hollow cylindrical structure (first hollow structure) 12, a detection coil (first winding coil) 13, and a multi-core wire (first multi-core wire) 14. The cylindrical molding core 11 is a magnetic body formed into a hollow cylindrical shape, and is disposed inside a hollow cylindrical structure 12 that is also formed into a hollow cylindrical shape. Moreover, the cylindrical molded core 11 is molded into a cylindrical shape using a soft magnetic permalloy foil strip having a thickness of approximately 1 μm to 1000 μm, thereby improving the responsiveness to minute changes in the magnetic field. The hollow cylindrical structure 12 is made by processing a non-magnetic material such as alumina or steatite into a cylindrical shape.

[0013] The detection coil 13 is configured by winding an enameled wire 13A spirally around the outer circumferential surface of the hollow cylindrical structure 12. The multi-core wire 14 is arranged at the axial center O of the hollow portion of the cylindrical core 11 and is used as an exciting coil that generates an exciting magnetic field when a current is applied. Specifically, the multi-core wire 14 is made of a Litz wire in which a plurality of thin insulated conductor wires 15 are twisted together.

[0014] In the magnetic detector 100 described above, by arranging the multi-core wire 14 at the axial center O of the cylindrical molded core 11 to form an excitation coil, the distance between the cylindrical molded core 11 and the detection coil 13 can be kept minimum and constant, minimizing the loss of the magnetic field, which attenuates as the cube of the separation distance, and generating a stable excitation magnetic field with a small current. Furthermore, the magnetic detector 100 uses a multi-core wire 14 made of a Litz wire formed by twisting together multiple thin insulated conductors 15, thereby enabling it to detect minute magnetic fields or minute currents such as those of the earth's magnetism with high sensitivity and high responsiveness.

[0015] In the magnetic detector 100, the multi-core wire 14 is used as an excitation coil, and changes in the excitation magnetic field are detected by the detection coil 13. However, this is not limited to this, and a reverse connection may be used in which the detection coil 13 is used as an excitation coil, and changes in the excitation magnetic field are detected by the multi-core wire 14.

[0016] Second Embodiment Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. The magnetic detector 200 shown in FIGS. 2 and 3 has a structure in which two magnetic detectors 100 and 101 having the structure shown in FIG. 1 are arranged in parallel and adjacent to each other.

[0017] The magnetic detectors 100 and 101 have the same basic configuration. In this embodiment, the cylindrical molded core (magnetic core) 11 includes a first magnetic core 11-1 and a second magnetic core 11-2. The hollow cylindrical structure 12 includes a first hollow structure 12-1 and a second hollow structure 12-2. That is, the magnetic detector 100 has a first hollow structure 12-1 in which a first magnetic core 11-1 is disposed, and the magnetic detector 101 has a second hollow structure 12-2 in which a second magnetic core 11-2 is disposed. In these magnetic detectors 100 and 101, the cylindrical molding core 11 is formed to have a length that does not exceed the hollow cylindrical structure 12. For example, the first hollow structural body 12-1 and the second hollow structural body 12-2 may be formed to have the same length.

[0018] The detection coil 13 is a spirally wound enameled wire 13A around the outer surface of the hollow cylindrical structure 12, and is wound clockwise in both the magnetic detectors 100 and 101 when viewed from the left side of the figure along the axial center O. The detection coil 13 is formed from a single enameled wire 13A. In addition, in the detection coil 13, the part wound around the first hollow structure 12-1 is referred to as the first detection coil (first winding coil) 13-1, and the part wound around the second hollow structure 12-2 is referred to as the second detection coil (second winding coil) 13-2. Here, in these magnetic detectors 100, 101, the first detection coil 13-1 and the second detection coil 13-2 are connected so that the direction of the detection magnetic field generated is a direction in which the magnetic fields reinforce each other around the hollow cylindrical structure 12 (first hollow structure 12-1 and second hollow structure 12-2) that is sheathed in the cylindrical molding core 11.

[0019] The multi-core wire 14 uses a Litz wire made of a plurality of insulated thin conductors 15 twisted together as the wire material, and is arranged at the axial center O of the cylindrical core 11 of each of the magnetic detectors 100 and 101 . As shown in FIG. 3, the multi-core wire 14 has a terminal end 15a of the conductor 15 that has passed through the magnetic detector 100 and becomes a starting end 15b when it enters the magnetic detector 101. Furthermore, in this multi-core wire 14, the terminal end 15c of the conductor 15 that has passed through the magnetic detector 101 becomes the starting end 15d when it enters the magnetic detector 100.

[0020] In this multi-core wire 14, by continuously routing the conductors 15 between the magnetic detectors 100 and 101, the conductors 15 can be connected in series and the direction of the excitation magnetic field can be set to be the same around each cylindrical molding core 11. In the multifilamentary wire 14, the portion located within the first hollow structural body 12-1 is referred to as a first multifilamentary wire 14-1, and the portion located within the second hollow structural body 12-2 is referred to as a multifilamentary wire 14-2. The first detection coil 13-1 can detect a first detection magnetic field around the first magnetic core 11-1, between the first hollow structure 12-1 and the second hollow structure 12-2. The second detection coil 13-2 can detect a second detection magnetic field around the second magnetic core 11-2, between the first hollow structure 12-1 and the second hollow structure 12-2.

[0021] In the magnetic detector 200 consisting of the magnetic detectors 100 and 101 described above, a multi-core wire 14 is arranged at the axial center O of each cylindrical molding core 11 to form an excitation coil, thereby making it possible to keep the distance between the cylindrical molding core 11 and the detection coil 13 at a minimum and constant. As a result, in these magnetic detectors 100 and 101, loss of the magnetic field can be minimized and a stable excitation magnetic field can be generated with a small current. Furthermore, these magnetic detectors 100 and 101 use a multi-core wire 14 made of a Litz wire formed by twisting together multiple thin insulated conductors 15, thereby enabling detection of minute magnetic fields or minute currents such as those of the earth's magnetism with high sensitivity and high responsiveness.

[0022] In the above embodiment, the enameled wire 13A of the detection coil 13 is wound around each hollow cylindrical structure 12 of the magnetic detectors 100 and 101 that constitute the magnetic detector 200 so that the wires are reinforced, but the enameled wire of the detection coil may be configured as in the magnetic detector 200'. That is, as shown in FIG. 4, in a magnetic detector 200', an enameled wire 13A' of a detection coil 13' is provided in a spiral shape so as to collectively wrap around the hollow cylindrical structures 12 of the magnetic detectors 100 and 101 arranged in parallel. In addition, such a magnetic detector 200' can also generate a detection magnetic field around each cylindrical molding core 11 in a direction that reinforces the magnetic field. In addition, in the detection coil 13', the part wound around the hollow cylindrical structure 12 of the magnetic detector 100 is defined as the first winding coil 16, and the part wound around the hollow cylindrical structure 12 of the magnetic detector 101 is defined as the second winding coil 17.

[0023] Third Embodiment Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. As shown in FIG. 5, the magnetic detector 300 includes a first hollow structure 301 , a first magnetic core 302 , a first multi-core wire 303 , and a first winding coil 304 . The first hollow structure 301 is formed in a cylindrical shape, and a cylindrical first magnetic core 302 is disposed inside the first hollow structure 301.

[0024] The first multifilamentary wire 303 is disposed in the first magnetic core 302 in the cylindrical axis direction (indicated by symbol O). The first winding coil 304 is wound around the outer periphery of the first hollow structure 301 . In magnetic detector 300 configured as above, first multicore wire 303 is used as an exciting coil, so that first winding coil 304 can detect minute currents with high sensitivity.

[0025] <Fourth embodiment> Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. As shown in FIG. 6, the method for constructing the magnetic detector includes the following steps:

[0026] [Step S1] A cylindrical magnetic core is placed inside a hollow structure (first hollow structure).

[0027] [Step S2] A multi-filamentary wire (first multi-filamentary wire) is arranged in the cylindrical axis direction within a magnetic core (first magnetic core).

[0028] [Step S3] A winding coil (first winding coil) is wound around the outer periphery of the hollow structure. However, steps S1 and subsequent steps may be carried out after winding a winding coil around the outer periphery of the hollow structure.

[0029] In the magnetic detector constructed as described above, by using a multi-core wire as an excitation coil, minute currents can be detected with high sensitivity by the winding coil.

[0030] <Modification> The above embodiments may be modified as follows.

[0031] (Variation 1) The cylindrical molded core in each of the above embodiments may be made of Co-based or Fe-based amorphous metal, nanocrystalline soft magnetic material, or the like.

[0032] (Variation 2) The hollow cylindrical structure of each of the above embodiments may be made of titanium, a non-magnetic metal, inconel, SUS (Steel Use Stainless) 304, or the like, which is a metal with low magnetic properties. Such hollow cylindrical structures have higher strength than ceramics such as alumina, and by reducing the thickness of the cylinder, the distance between the cylindrical molding core and the detection coil can be reduced, thereby improving the detection sensitivity of the detection coil.

[0033] (Variation 3) The multi-core wire in each of the above embodiments has a structure in which insulated, independent conductors such as Litz wire are twisted together, but this is not limited to this, and a bundle of enameled wires that serve as conductors, a flat cable made of laminated conductors, etc. may also be used.

[0034] (Variation 4) In each of the above embodiments, the magnetic detector is constructed by arranging two magnetic detectors in parallel, but three or more of these magnetic detectors may be installed by setting the direction in which the detected magnetic field is generated to be a reinforced direction around the cylindrical molding core.

[0035] (Variation 5) In the above-described embodiments, the first hollow structure and the second hollow structure are cylindrical, but may be any other shape as long as they are cylindrical.

[0036] (Variation 6) Similarly, in each of the above embodiments, the first magnetic core and the second magnetic core are cylindrical, but may be any cylindrical shape.

[0037] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art within the description of the present disclosure can be made to the configuration and details of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0038] Some or all of the above-described embodiments can be described as, but are not limited to, the following supplementary notes.

[0039] (Appendix 1) a cylindrical first hollow structure; a cylindrical first magnetic core disposed in the first hollow structure; a first multifilamentary wire disposed in the first magnetic core in the axial direction; a first winding coil wound around the outer periphery of the first hollow structure; Equipped with Magnetic detector.

[0040] (Appendix 2) a cylindrical second hollow structure; a cylindrical second magnetic core disposed in the second hollow structure; a second multifilamentary wire disposed in the second magnetic core in the axial direction of the cylinder; a second winding coil wound around the outer periphery of the second hollow structure; Furthermore, At least two of the first hollow structures and the second hollow structures are arranged in parallel and adjacent to each other, The first multifilamentary wire and the second multifilamentary wire are connected in series at the end and start ends of the respective core wires, the first winding coil is capable of detecting a first detection magnetic field around the first magnetic core, between the first hollow structure and the second hollow structure; the second winding coil is capable of detecting a second detection magnetic field around the second magnetic core, between the first hollow structure and the second hollow structure; The first winding coil and the second winding coil are connected so that the first detection magnetic field and the second detection magnetic field are constructively coupled around the first hollow structure and the second hollow structure. 10. The magnetic detector of claim 1.

[0041] (Appendix 3) the first winding coil is wound spirally around the outer circumferential surface of the first hollow structure, The second winding coil is wound spirally around the outer circumferential surface of the second hollow structure. 10. The magnetic detector of claim 2.

[0042] (Appendix 4) the first winding coil and the second winding coil are made of the same conductor, The conducting wire is spirally provided so as to wrap around the first hollow structure and the second hollow structure collectively. 4. The magnetic detector according to claim 2 or 3.

[0043] (Appendix 5) The first multi-core wire and the second multi-core wire are made of Litz wires formed by twisting together a plurality of insulated thin conductor wires. 5. The magnetic detector according to any one of appendices 2 to 4.

[0044] (Appendix 6) When the first multifilamentary wire and the second multifilamentary wire serve as excitation coils that generate an excitation magnetic field when a current is applied, the first winding coil and the second winding coil serve as detection coils that detect a magnetic field. 6. A magnetic detector according to any one of appendices 2 to 5.

[0045] (Appendix 7) When the first winding coil and the second winding coil serve as excitation coils that generate an excitation magnetic field when a current is applied, the first multifilamentary wire and the second multifilamentary wire serve as detection coils that detect a magnetic field. 7. A magnetic detector according to any one of appendices 2 to 6.

[0046] (Appendix 8) The first hollow structure having the first magnetic core disposed therein and the second hollow structure having the second magnetic core disposed therein are formed to have the same length. 8. A magnetic detector according to any one of appendices 2 to 7.

[0047] (Appendix 9) the first multi-core wire and the second multi-core wire are flat cables formed by stacking conductor wires; 9. A magnetic detector according to any one of appendices 2 to 8.

[0048] (Appendix 10) a cylindrical first magnetic core is disposed in the first hollow structure; a first multifilamentary wire disposed in the first magnetic core in a cylindrical axis direction; a first winding coil wound around the outer periphery of the first hollow structure; How to build a magnetic detector.

[0049] (Appendix 11) The first multi-core wire is formed by twisting together a plurality of insulated thin conductor wires as wire materials. 11. A method of constructing a magnetic detector as described in claim 10.

[0050] (Appendix 12) a cylindrical second hollow structure; a cylindrical second magnetic core disposed in the second hollow structure; a second multifilamentary wire disposed in the second magnetic core in the axial direction of the cylinder; a second winding coil wound around the outer periphery of the second hollow structure; Furthermore, At least two of the first hollow structures and the second hollow structures are arranged in parallel and adjacent to each other, the first multicore wire and the second multicore wire are connected in series at the end and start ends of the respective core wires, the first winding coil is capable of detecting a first detection magnetic field around the first magnetic core, between the first hollow structure and the second hollow structure; the second winding coil is capable of detecting a second detection magnetic field around the second magnetic core, between the first hollow structure and the second hollow structure; The first winding coil and the second winding coil are connected so that the first detection magnetic field and the second detection magnetic field are constructively coupled around the first hollow structure and the second hollow structure. 12. A method of constructing a magnetic detector according to claim 10 or 11.

[0051] (Appendix 13) the first winding coil is wound spirally around the outer circumferential surface of the first hollow structure, The second winding coil is wound spirally around the outer circumferential surface of the second hollow structure. 13. A method of constructing a magnetic detector as described in claim 12.

[0052] (Appendix 14) the first winding coil and the second winding coil are made of the same conductor, The conducting wire is spirally provided so as to wrap around the first hollow structure and the second hollow structure collectively. 14. A method of constructing a magnetic detector according to claim 12 or 13.

[0053] (Appendix 15) The first multi-core wire and the second multi-core wire are made of Litz wires formed by twisting together a plurality of insulated thin conductor wires. A method for constructing a magnetic detector according to any one of appendices 12 to 14.

[0054] (Appendix 16) When the first multifilamentary wire and the second multifilamentary wire serve as excitation coils that generate an excitation magnetic field when a current is applied, the first winding coil and the second winding coil serve as detection coils that detect a magnetic field. A method for constructing a magnetic detector according to any one of appendices 12 to 15.

[0055] (Appendix 17) When the first winding coil and the second winding coil serve as excitation coils that generate an excitation magnetic field when a current is applied, the first multicore wire and the second multicore wire serve as detection coils that detect a magnetic field. A method for constructing a magnetic detector according to any one of appendices 12 to 16.

[0056] (Appendix 18) The first hollow structure having the first magnetic core installed therein and the second hollow structure having the second magnetic core installed therein are formed to have the same length. A method for constructing a magnetic detector according to any one of appendices 12 to 17.

[0057] (Appendix 19) the first multi-core wire and the second multi-core wire are flat cables formed by stacking conductor wires; A method for constructing a magnetic detector according to any one of appendices 12 to 18. [Explanation of symbols]

[0058] 11 Cylindrical molded core (first magnetic core) 11-1 First cylindrical molded core (first magnetic core) 11-2 Second cylindrical molded core (second magnetic core) 12 Hollow cylindrical structure (first hollow structure) 12-1 First hollow cylindrical structure (first hollow structure) 12-2 Second hollow cylindrical structure (second hollow structure) 13 Detection coil (first winding coil) 13' detection coil 13-1 First detection coil (first winding coil) 13-2 Second detection coil (second winding coil) 13A enameled wire 13A' enameled wire 14 Multi-core wire (first multi-core wire) 14-1 First multi-core wire 14-2 Second multi-core wire 15 Conductor 15a Termination section 15b Starting end 15c Termination section 15d Starting end 16 First winding coil 17 Second winding coil 100 Magnetic detector 101 Magnetic detector 200 Magnetic Detector 200' Magnetic Detector 300 Magnetic Detector 301 First hollow structure 302 First magnetic core 303 First multi-core wire 304 First winding coil

Claims

1. a cylindrical first hollow structure; a cylindrical first magnetic core disposed in the first hollow structure; a first multifilamentary wire disposed in the first magnetic core in the axial direction; a first winding coil wound around the outer periphery of the first hollow structure; Equipped with Magnetic detector.

2. a cylindrical second hollow structure; a cylindrical second magnetic core disposed in the second hollow structure; a second multifilamentary wire disposed in the second magnetic core in the axial direction of the cylinder; a second winding coil wound around the outer periphery of the second hollow structure; Furthermore, At least two of the first hollow structures and the second hollow structures are arranged in parallel and adjacent to each other, The first multifilamentary wire and the second multifilamentary wire are connected in series at the end and start ends of the respective core wires, the first winding coil is capable of detecting a first detection magnetic field around the first magnetic core, between the first hollow structure and the second hollow structure; the second winding coil is capable of detecting a second detection magnetic field around the second magnetic core, between the first hollow structure and the second hollow structure; The first winding coil and the second winding coil are connected so that the first detection magnetic field and the second detection magnetic field are constructively coupled around the first hollow structure and the second hollow structure. The magnetic detector according to claim 1 .

3. the first winding coil is wound spirally around the outer circumferential surface of the first hollow structure, The second winding coil is wound spirally around the outer circumferential surface of the second hollow structure. The magnetic detector according to claim 2 .

4. the first winding coil and the second winding coil are made of the same conductor, The conducting wire is spirally provided so as to collectively wrap around the first hollow structure and the second hollow structure.

4. The magnetic detector according to claim 2 or 3.

5. The first multi-core wire and the second multi-core wire are made of Litz wires formed by twisting together a plurality of insulated thin conductor wires.

4. The magnetic detector according to claim 2 or 3.

6. When the first multifilamentary wire and the second multifilamentary wire serve as excitation coils that generate an excitation magnetic field when a current is applied, the first winding coil and the second winding coil serve as detection coils that detect a magnetic field.

4. The magnetic detector according to claim 2 or 3.

7. When the first winding coil and the second winding coil serve as excitation coils that generate an excitation magnetic field when a current is applied, the first multicore wire and the second multicore wire serve as detection coils that detect a magnetic field.

4. The magnetic detector according to claim 2 or 3.

8. The first hollow structure having the first magnetic core disposed therein and the second hollow structure having the second magnetic core disposed therein are formed to have the same length.

4. The magnetic detector according to claim 2 or 3.

9. a cylindrical first magnetic core is disposed in the first hollow structure; a first multifilamentary wire disposed in the first magnetic core in a cylindrical axis direction; a winding coil is wound around the outer periphery of the first hollow structure; How to build a magnetic detector.

10. The first multi-core wire is formed by twisting together a plurality of insulated thin conductor wires as wire materials.

10. A method for constructing a magnetic detector according to claim 9.

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