JP2019211423A - Clamp sensors and clamp meter - Google Patents

Abstract

To provide a clamp sensor capable of detecting a small current flowing through a large area structure containing a detection line.SOLUTION: By inserting a connecting core 4 that can be bent and stretched by removing a first attachable and detachable end 4a and a second attachable and detachable end 4b into a coil holding tube 5, a clamp sensor 2 for holding the state of placing the coil on the outer periphery of the connecting core 4 is constituted. By surrounding a large area structure including the detection line in this clamp sensor 2 and connecting the first attachable and detachable end 4a and the second attachable and detachable end 4b, the connecting core 4 becomes an annular core surrounding the large area structure, and even a small current of about several mA detection target, the secondary current corresponding to the number of turns ratio of the coil provided in the coil holding tube 5 can be obtained by the clamp sensor 2. Thus, the measuring device 3 can calculate and display a small current value to be detected based on the current detection signal from the clamp sensor 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a clamp sensor that can handle a large-area structure including a line to be detected, and a clamp meter that can detect current using the clamp sensor.

  When measuring the current of the detected line (or measuring the leakage current in the circuit) without turning off the circuit power supply, clamp the detected line with the clamp sensor and the current flowing through the detected line (or the leakage current in the circuit) A clamp meter that obtains a current value from a magnetic field generated by (2) is known. If an AC circuit is to be detected, a CT (Current Transformer) type clamp meter that converts a measurement current into a secondary current according to the turns ratio of the coil is widely used (see, for example, Patent Document 1). ). Moreover, the cross section of a clamp location becomes a large area in the large structure (column etc.) containing the to-be-detected line. When performing current measurement of such a large-area structure, a Rogowski coil clamp meter that can detect current by clamping the structure can be used (see, for example, Patent Document 2).

JP 2018-031608 A JP 2011-174769 A

  However, although the CT-type clamp sensor described in Patent Document 1 described above can measure a mA-level minute current, a standard commercial product has only a clamp diameter of about 70 mm and has a large area including a detected line. The entire structure cannot be clamped with a large diameter. On the other hand, the Rogowski coil (air-core coil) described in Patent Document 2 can clamp a large area structure including a detected wire with a large diameter, but measures a low current of 10 A or less (such as a minute leakage current). I can't.

  In electrical maintenance and inspection, it is necessary to measure a minute leakage current (or ground current) to determine the quality of the insulation state. Even if the target is a large-area structure, the minute current is necessary to determine the insulation state. It is necessary to enable measurement.

  Therefore, an object of the present invention is to provide a clamp sensor and a clamp meter that can detect a minute current flowing in a large-area structure including a detected line.

  In order to solve the above-described problem, the invention according to claim 1 is capable of arranging a coil on the outer periphery of the connection core that forms an annular core that surrounds the detected wire in a non-contact manner by connecting both ends. A clamp sensor comprising a coil body, wherein the connection core is formed of a high magnetic permeability soft magnetic material, and a first connection portion and a second connection portion are formed at a pair of end portions that are most separated from each other. A plurality of element bodies are used, and the first connecting portion and the second connecting portion are connected so as to form a uniaxial joint that can be rotated, thereby forming a connecting structure in which both ends are opened and connected at one end. The first connecting part that is not connected in the connecting element body is a first attaching / detaching end part, and the second connecting part that is not connected in the connecting element body at the other end is the second attaching / detaching end part. And the second detachable end are connected so that all connecting elements are closed in a ring shape An annular core can be configured, and the coil body has an inner space portion into which the connecting core can be inserted, and the first attaching / detaching end portion and the second attaching / detaching end portion of the connecting core are exposed from each end portion, respectively. A flexible inner layer tube that can be easily deformed following the deformation of the connecting core, and a coil formed by winding a magnet wire around the outer surface of the inner layer tube. The outer surface side of the body is covered with an insulating outer tube, and a connecting core is inserted into the inner space of the coil body.

  According to a second aspect of the present invention, in the clamp sensor according to the first aspect, the connection element body of the connection core is obtained by laminating a plurality of base materials which are plate materials of a high magnetic permeability soft magnetic material. The base material is configured to have a thickness, and the projecting end edge has a projecting end edge projecting in an arc shape that is equidistant from an axial position connected to form a uniaxial joint on one end side. A concave end edge portion that is recessed in a circular arc shape with the same degree of curvature as the other portion is provided on the other end side, and the base body is alternately laminated with the convex end edge portion and the concave end edge portion, thereby connecting elements. The first connecting part and the second connecting part have a fitting structure in which the convex end edge part and the concave end edge part mesh with each other, and each connecting element body connected by a uniaxial joint is provided. The base material should be able to rotate within the required range without obstructing each other's convex edge and concave edge. The features.

  According to a third aspect of the present invention, in the clamp sensor according to the first or second aspect, an introduction guide for guiding the first detachable end portion and the second detachable end portion to a required fitting position. The parts are provided at both ends, respectively.

  In order to solve the above problem, a clamp meter according to a fourth aspect includes the clamp sensor according to any one of the first to third aspects, and a detection signal obtained from a coil of the clamp sensor. Provided with a measuring device for calculating a current value to be measured.

  According to the clamp sensor according to the present invention, an annular iron core having a necessary and sufficient diameter can be configured by a connecting core in which an appropriate number of connecting elements are connected in accordance with a large-area structure including a detection target line to be measured. . Then, a large-area structure is enclosed with the first attaching / detaching portion and the second attaching / detaching portion of the connecting core being opened, and the outer periphery of the annular core formed by connecting the first attaching / detaching portion and the second attaching / detaching portion is a coil. The coil is placed by the body. Therefore, if a large area structure is clamped with a clamp sensor, a secondary current corresponding to the coil turns ratio can be obtained from the magnetic field change caused by the AC current to be detected, so a clamp meter that can detect and measure minute currents. It becomes.

It is a schematic block diagram of the clamp meter which concerns on embodiment of this invention. The clamp sensor used for a clamp meter is shown, (a) is a partially missing plan view, (b) is a partially missing side view. It is a bird's-eye perspective view of the basic link which constitutes a connection core. It is a top view of the base material which comprises a basic link. It is assembly explanatory drawing of the basic link using a base material. (A) is a rear view of a basic link. FIG. 6B is an enlarged schematic end view in the direction of arrows VIb-VIb in FIG. (A) is a top view of the connected 1st basic link and 2nd basic link. (B) is an enlarged schematic end view in the direction of arrows VIIb-VIIb in FIG. 7 (a). It is manufacturing process explanatory drawing of a coil body. It is assembly process explanatory drawing of a clamp sensor. It is connection process explanatory drawing of the 1st connection guide and 2nd connection guide of a clamp sensor. (A) is a schematic cross-sectional view before the connection of the 1st connection guide and 2nd connection guide of a clamp sensor. (B) is a schematic cross-sectional view of the clamp sensor after the first connection guide and the second connection guide are connected. (A) is a schematic longitudinal cross-sectional view before the connection of the 1st connection guide and 2nd connection guide of a clamp sensor. (B) is a schematic longitudinal cross-sectional view after the 1st connection guide and 2nd connection guide of a clamp sensor are connected. FIG. 12C is an enlarged schematic cross-sectional view in the direction of arrow XIIc-XIIc in FIG. (D) is an expansion schematic sectional drawing of the XIId-XIId arrow direction in FIG.12 (b). It is a usage-method explanatory drawing when measuring the grounding current (or leakage current) of a utility pole with the clamp meter which concerns on this embodiment.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a schematic configuration of a clamp meter 1. The clamp meter 1 performs a predetermined calculation based on a clamp sensor 2 that clamps a line to be measured and a detection current of the clamp sensor 2, and the measurement result is converted into a digital value. (Or an analog value).

  The clamp sensor 2 includes a connecting core 4 that is an annular iron core that surrounds a detected line in a non-contact manner by connecting both ends, and a coil holding tube 5 that holds a state in which a coil is disposed on the outer periphery of the connecting core 4. . In addition, the connection core 4 can be bent and extended by removing the 1st attachment / detachment edge part 4a and the 2nd attachment / detachment edge part 4b so that it may mention later. Therefore, when a large-area structure (for example, a power pole) including a detected line is surrounded by the clamp sensor 2 and the first attaching / detaching end 4a and the second attaching / detaching end 4b are connected, an annular core that surrounds the peripheral surface of the power pole is obtained. be able to. The connecting core 4 that is an annular core functions as a closed magnetic circuit that efficiently passes the magnetic flux generated by the current flowing through the detection line.

  Furthermore, the coil holding tube 5 has flexibility and insulation that can be deformed without difficulty following the deformation of the connecting core 4. Therefore, when the connecting core 4 is closed to form an annular iron core, the coil in the coil holding tube 5 is also arranged in an annular shape, and when the magnetic flux is concentrated on the annular iron core due to current flowing through the detected wire, A secondary current flows through the coil of the coil holding tube 5 so as to cancel out. Since this secondary current can be obtained with a magnitude corresponding to the turn ratio of the coil in the coil holding tube 5 with respect to the primary current flowing through the detection line, detection sensitivity capable of detecting a minute current of about several mA. Easy to set.

  In addition, the first connecting guide 6 is provided on the first attaching / detaching end 4a side of the connecting core 4 in the clamp sensor 2 of the present embodiment, so that the work of clamping the large area structure by the clamp sensor 2 is not complicated. A second connection guide 7 is provided on the detachable end 4b side. The first and second connection guides 6 and 7 have a structure (which will be described in detail later) that allows the first attachment / detachment end 4a and the second attachment / detachment end 4b to be attached / detached easily. The connection cable 8 is extended from the first connection guide 6 in the clamp sensor 2 and connected to the measuring device 3. The measuring device 3 that receives the detection signal from the coil in the coil holding tube 5 via the connection cable 8 includes a shunt resistor for current detection, and the current value flowing through the measured line from the detection current of the clamp sensor 2 is calculated. A function for calculating and displaying on the display unit is provided.

  A schematic structure of the clamp sensor 2 described above is shown in FIG. The clamp sensor 2 can be used according to the direction of the line to be detected. However, in the following description, for the sake of convenience, the cross-sectional direction that can be clamped by the clamp sensor 2 is the horizontal direction (or horizontal direction), and the direction orthogonal thereto is the vertical direction. It demonstrates as a direction (or up-down direction). Accordingly, FIG. 2 (a) shows a part of the clamp sensor 2 cut out in the horizontal direction, and FIG. 2 (b) shows a part of the clamp sensor 2 cut out in the vertical direction to show the inside. It is a thing.

  The connection core 4 includes, for example, 14 first connection links, a first basic link 40-1, a second basic link 40-2, ..., a twelfth basic link 40-12, a thirteenth basic link 40-13, 14 basic links 40-14 are connected. The first to fourteenth basic links 40-1 to 40-14 all have the same shape, and are simply referred to as the basic link 40 when there is no need to distinguish them. These first to fourteenth basic links 40-1 to 40-14 are obtained by laminating a base material 41, which will be described later, and fixing with a rivet 42. The 2nd connection part 14b is formed.

  When connecting the 1st basic link 40-1 and the 2nd basic link 40-2, the 2nd connection part 40b in the 1st basic link 40-1 (this is called the 1st basic link 2nd connection part 40-1b. The second basic link first connecting portion 40-2a is connected by the uniaxial joint connecting portion 43 so as to be a rotatable uniaxial joint. When connecting the 2nd basic link 40-2 and the 3rd basic link 40-3, the 2nd basic link 2nd connection part 40-2b and the 3rd basic link 1st connection part 40-3a are uniaxial joint connection parts. 43 are connected. Since the same applies to the case where the third basic link 40-3 to the twelfth basic link 40-12 are connected, the description thereof is omitted. When connecting the twelfth basic link 40-12 and the thirteenth basic link 40-13, the twelfth basic link second connecting portion 40-12b and the thirteenth basic link first connecting portion 40-13a are uniaxial joint connecting portions. 43 are connected. When connecting the thirteenth basic link 40-13 and the fourteenth basic link 40-14, the thirteenth basic link second connecting portion 40-13b and the fourteenth basic link first connecting portion 40-14a are uniaxially connected. The parts 43 are connected. By doing so, the connecting core 4 has a daisy chain-like connecting structure with both ends open. At this time, the 1st basic link 40-1a which is not connected remains in the 1st basic link 40-1 which is a connecting element body of one end, and the 14th basic link which is a connecting element body of the other end remains. The 14th basic link 2nd connection part 40-14b which is not connected by 40-14 remains.

  Therefore, the 1st basic link 1st connection part 40-1a can be used as the 1st detachable end part 4a, and the 14th basic link 2nd connection part 40-14b can be used as the 2nd detachable end part 4b. And by connecting these 1st attachment / detachment edge part 4a and 2nd attachment / detachment edge part 4b, the 1st-14th basic link 40-1-40-14 can comprise the cyclic | annular iron core closed cyclically | annularly. The first basic link 40-1 to the fourteenth basic link 40-14 are all connected by unifying the direction of the uniaxial joint in the vertical direction. The rotational direction of 40-14 can be regulated in the horizontal direction. Thus, if the rotation direction of the first basic link 40-1 to the fourteenth basic link 40-14 is restricted to the horizontal direction, the connection between the first attachment / detachment end 4a and the second attachment / detachment end 4b is also possible. It can be performed almost in a horizontal plane.

  On the other hand, in the coil holding tube 5, the outer surface side of the coil body 53 in which the coil 52 is formed by winding the magnet wire 521 around the outer peripheral surface 51 a of the inner layer tube 51 is covered with the outer layer tube 54. The inner layer tube 51 and the outer layer tube 54 have flexibility and insulating properties that can be deformed without difficulty following the deformation of the connecting core 4. The inner tube 51 has an inner space 51b into which the connecting core 4 can be inserted, and has a length that allows the first removable end 4a and the second removable end 4b of the connecting core 4 to be exposed from each end. Thus, the outer layer tube 54 is also set to an equivalent length, and each end is covered with an insulating cover 55. The first lead wire 521a and the second lead wire 521b, which are the winding start portion or the winding end portion of the magnet wire 521, are drawn out from one side of the coil holding tube 5.

  Next, the detailed structure of the basic link 40 which comprises the connection core 4 is demonstrated. FIG. 3 shows the appearance of the basic link 40 which is a connected element body. The basic link 40 includes a first base material 41-1, a second base material 41-2,..., Which are plate materials (for example, thickness 1 [mm]) of a high magnetic permeability soft magnetic material (for example, permalloy). 6 base material 41-6 and seventh base material 41-7 are laminated. In a state where the first base material 41-1 to the seventh base material 41-7 are overlapped, they are fixed integrally with a rivet 42 of a caulking fixing method. Note that the first to seventh base materials 41-1 to 41-7 are all the same shape, and are simply referred to as the base material 41 when it is not necessary to distinguish between them.

  FIG. 4 shows a plane of the base material 41 (for example, a surface on which the upper surface 41a faces). The base material 41 is a long plate material having a gentle arc shape, and generally, an outer arc edge portion 411 and an inner arc edge portion 412 which are two sides in the longitudinal direction, and a convex end portion 413 which is two sides in the short direction. And a concave edge 414. For example, assuming an arc of R160 [mm] from the virtual origin O (hereinafter referred to as a virtual center arc), an arc that is about 3.5 mm away from the virtual center arc (for example, R163.5 from the origin O) The outer arc-shaped edge 411 is formed so as to overlap the [mm] arc). Further, the inner arc-shaped edge 412 is formed so as to overlap with an arc (for example, an arc of R156.5 [mm] from the origin O) separated by about 3.5 [mm] inside the virtual center arc. Further, the convex edge portion 413 is provided on one short side of the base material 41 (for example, the left side when viewed from the upper surface 41a or the right side when viewed from the lower surface 41b). Further, the concave edge 414 is provided on the other short side of the base material (for example, the right side when viewed from the upper surface 41a or the left side when viewed from the lower surface 41b). The separation distance between the outer arcuate edge 411 and the inner arcuate edge 412 is about 7 [mm] (3.5 [mm] × 2), and the first to seventh base members 41-1 to 41-7 are Since the overlapped thickness is also about 7 [mm], the longitudinal section in the short direction of the basic link 40 is substantially square.

  On the virtual center arc of the base material 41, a first fixing hole 415a, a second fixing hole 415b, and a third fixing hole 415c each having a diameter of 2 mm are provided. For example, the angle from the origin O to the center of the first fixing hole 415a is the same as the angle from the origin O to the center of the third fixing hole 415c with respect to a virtual line passing from the origin O to the center of the second fixing hole 415b. The opening positions of the first to third fixing holes 415a to 415c are determined so as to be. In this case, when the two base members 41 are overlapped so that the upper surface 41a and the lower surface 41b face each other (when the convex end edge portion 413 and the concave end edge portion 414 are reversed so as to face each other) ), It is possible to make all the three holes in the two base members 41 stacked coincide. That is, when the two base members 41 are aligned so that the respective second fixing holes 415 b communicate with each other, the first fixing hole 415 a and the third fixing hole 415 c in one base member 41 become the other base member 41. The third fixing hole 415c and the first fixing hole 415a overlap. At this time, the two overlapping base members 41 can keep the outer arcuate edge 411 and the inner arcuate edge 412 in agreement.

  Therefore, when the basic link 40 has a structure in which a plurality of (for example, seven) base members 41 are stacked, the base links 41 can be stacked by alternately changing the directions of the base members 41 as shown in FIG. First, the second base material 41-2 with the lower surface 41b facing upward is stacked under the first base material 41-1 with the upper surface 41a facing upward. A third base material 41-3 with the upper surface 41a facing upward is overlaid thereon. A fourth base material 41-4 with the lower surface 41b facing upward is overlaid thereon. A fifth base material 41-5 with the upper surface 41a facing upward is overlaid thereon. A sixth base material 41-6 with the lower surface 41b facing upward is overlaid thereon. A seventh base material 41-7 with the upper surface 41a facing upward is overlaid thereon. The rivet 42 is inserted into the first to third fixing holes 415c penetrating from the first base material 41-1 to the seventh base material 41-7, and fixed by caulking. As shown in FIG. 6, the rivet 42 has a head portion 42a positioned on the upper surface 41a side of the first base material 41-1, and the shaft portion 42b is inserted into the first to third fixing holes 415a to 415c. The caulking portion 42c is formed on the lower surface 41b side of the seventh base material 41-7.

  As described above, the first and second connecting portions 40a and 40b in the basic link 40 formed by laminating the first to seventh base members 41-1 to 41-7 are both convex edge portions 413 and concave shapes. The edge portions 414 are alternately overlapped. The first connecting portion 40a has a “concave / concave / convex / concave / concave” structure from the first base material 41-1 to the seventh base material 41-7, and the second connecting portion 40b is formed from the first base material 41-1. It becomes a structure of "convex unevenness unevenness" toward the seventh base material 41-7. That is, the first connecting portion 40a and the second connecting portion 40b of the basic link 40 have a fitting structure that meshes with each other.

  In addition, the first connecting portion 40a and the second connecting portion 40b of the basic link 40 are connected by the uniaxial joint connecting portion 43 so as to form a uniaxial joint that can be smoothly rotated. The protruding shape of the portion 413 and the recessed shape of the concave edge portion 414 are set as follows.

  A communication hole 416 for connection by the uniaxial joint connection portion 43 is provided on the convex end edge 413 side of the base material 41. The position of the communication hole 416 is determined such that the arc having the radius r1 from the center of the communication hole 416 substantially overlaps the bulging edge of the convex edge 413 (see each convex edge 413 in FIG. 5). Further, when the two basic links 40 are overlapped in the opposite direction, an arc having a radius r2 from the center of the communication hole 416 adjacent to the concave edge 414 overlaps with the recessed edge of the concave edge 414 (for example, , See each concave edge 414 in FIG. 5). At this time, if “r1 ≦ r2” is set, all of the communication holes 416 are in a state where one first connecting portion 40a and the other second connecting portion 40b of the pair of basic links 40 are engaged with each other. The opening position can be adjusted.

  In designing the base member 41 described above, if both the convex edge portion 413 and the concave edge portion 414 have an arcuate range close to 180 °, the first connection portion 40a and the second connection portion of the pair of basic links 40 are provided. It becomes impossible to rotate while the portion 40b is engaged. Therefore, it is desirable to appropriately set the arc-shaped ranges of the convex edge portion 413 and the concave edge portion 414 in accordance with the allowable rotation range. It is desirable that the convex edge 413 and the concave edge 414 have outer edge shapes that are smoothly connected to the outer arc edge 411 and the inner arc edge 412 respectively. If there is a step or an acute angle at the connection between the convex edge 413 and the concave edge 414 and the outer arc edge 411 and the inner arc edge 412, the connecting core 4 is inserted into the coil holding tube 5. There is a risk of damaging the inner surface of the inner tube 51.

  However, in the base material 41 of the connecting core 4 used in the clamp sensor 2 of the present embodiment, the width in the short direction (the separation distance between the outer arcuate edge 411 and the inner arcuate edge 412) is approximately r1 [mm] ×. 2. Therefore, when the arcuate range of the convex edge 413 is approximately 180 °, the connecting portion between one end of the convex edge 413 and the outer arcuate edge 411 and the other end of the convex edge 413 and the inner arc The connection portion with the edge 412 is smooth, and no step or the like occurs. On the other hand, chamfering (for example, R1) is applied to a connection portion between one end of the concave edge portion 414 and the outer arcuate edge portion 411 and a connection portion between the other end of the concave edge portion 414 and the inner arcuate edge portion 412. Thus, the connection is made smoothly so that no corners are formed.

  Further, when the radius r1 that determines the convex edge 413 and the radius r2 that determines the concave edge 414 are equal, when the first connecting portion 40a and the second connecting portion 40b of the pair of basic links 40 are connected, Depending on the processing accuracy, the opening position of the connection port 416 may not be adjusted. Even if the processing accuracy is good and “r1 = r2” is set or the opening position of the connection port 416 is exactly aligned, the convex edge portion 413 and the concave edge portion 414 come into surface contact in a long range. If the convex edge portion 413 and the concave edge portion 414 are in surface contact with each other, the sliding resistance increases accordingly, so that the connecting core 4 may be difficult to deform. However, if the radius r1 of the convex edge portion 413 is made extremely smaller than the radius r2 of the concave edge portion 414, the first connecting portion 40a and the second connecting portion 40b are engaged with each other. The facing area is reduced. If the facing area between the first connecting portion 40a and the second connecting portion 40b decreases, the magnetic resistance at the connecting portion between the base members 41 may increase, and the strength at the connecting portion between the base members 41 may decrease. The problem is also a concern. Therefore, when the first connecting portion 40a and the second connecting portion 40b of the pair of basic links 40 are engaged, the convex edge portion 413 and the concave edge portion 414 are set to be in contact with each other. It is desirable to keep it. For example, as shown in FIG. 4, when the radius r1 for determining the convex edge 413 is set to 3.5 [mm] and the radius r2 for determining the concave edge 414 is set to 3.6 [mm], the connection There is no hindrance to the deformation work of the core 4, and the magnetic resistance is not extremely increased at the connecting portion.

  One structural example of the uniaxial joint connection part 43 which connects a pair of basic links 40 provided with the 1st attachment / detachment edge part 4a and the 2nd attachment / detachment edge part 4b comprised as mentioned above is shown in FIG. The first connecting portion 40a and the second connecting portion 40b are engaged with each other so that the opening positions of the communication holes 416 in all the convex edge portions 413 are matched, and the connecting screw 431 is inserted in this state. When the head of the connecting screw 431 presses against the upper surface 41a of the first base member 41-1, the screw tip of 431 protrudes appropriately from the lower surface 41b of the seventh base member 41-7, so that the plain washer 432 and the spring washer 433 is inserted and fastened with a nut 434.

  At this time, if the nut 434 is tightened too much, the smooth rotation between the basic links 40 is hindered. Conversely, if the tightening is too weak, it becomes difficult to maintain the shape of the connecting core 4 itself. Thus, the work for clamping the detected line becomes complicated. Therefore, as a function of the uniaxial joint connecting portion 43, it is important to maintain an appropriate fastening state. For example, after tightening the nut 434 with a predetermined tightening torque (for example, 1.8 [kgf · cm]) with respect to the connecting screw 431, the nut 434 is loosened by a certain amount by returning 90 °, and a screw lock agent is applied to the nut 434. 435 is applied and fixed in this tightened state. In this case, since the smooth rotation between the basic links 40 is not hindered and it is not difficult to maintain the shape of the connecting core 4 itself, the handling of the connecting core 4 in the measurement work is improved, and the workability is improved. It can also contribute to improvement.

  An example of the manufacturing process of the coil body 53 in which the coil 52 can be arranged on the outer periphery of the connecting core 4 described above will be described with reference to FIG. First, a flexible and insulating inner tube 51 having a cylindrical outer peripheral surface 51a is prepared. The inner layer tube 51 includes an inner space portion 51b having a necessary and sufficient diameter for inserting the connecting core 4, and the first connecting portion 40a and the second detachable end portion 4b of the connecting core 4 protrude from both end openings. Is the length of Further, the inner layer tube 51 is fixed in a straight line by passing the straight metal rod 56 through the inner space 51 b of the inner layer tube 51. In this way, since the rigid metal rod 56 can be set in a shaft-rotating type winding machine using the rotating shaft as a rotating shaft, the magnet wire 521 is single-layered or multi-layered on the outer peripheral surface 51a of the inner tube 51 by the winding machine. Thus, the coil 52 can be formed. Then, the inner layer tube 51 in which the coil 52 is formed is removed from the winding machine, and the metal rod 56 is extracted (see FIGS. 8A to 8C). Thus, a coil body 53 is formed in which the coil 52 is formed by winding the magnet wire 521 around the outer surface of the inner layer tube 51 (see FIG. 8D). The winding start portion and winding end portion of the magnet wire 521 can be used as the first lead wire 521a and the second lead wire 521b.

  The coil body 53 formed as described above is inserted into the coil body insertion portion 54a of the flexible / insulating outer layer tube 54 (see FIG. 9A), so that the outer surface of the coil 52 is obtained. Can be covered with the outer layer tube 54. The outer layer tube 54 has the same length as the coil body 53, and the coil body insertion portion 54 a has a diameter necessary and sufficient for inserting the coil body 53. After the coil body 53 is inserted into the outer layer tube 54, an insulating cap 55 for securing a creepage distance is attached to both ends thereof to constitute the coil holding tube 5 (see FIG. 9B). Next, the connecting core 4 is inserted into the inner space 51 b of the inner layer tube 51 which is the innermost part of the coil holding tube 5, and the first attaching / detaching end 4 a and the second attaching / detaching end 4 b are respectively connected to both ends of the coil holding tube 5. By exposing, the clamp sensor 2 is obtained (see FIG. 9C).

  As shown in FIG. 9 (c), the first attaching / detaching end 4a and the second attaching / detaching end 4b are appropriately exposed at both ends of the clamp sensor 2, respectively. Therefore, the detected line is bent so as to be surrounded by the clamp sensor 2, and the first connecting part 40a that is the first attaching / detaching end part 4a and the second connecting part 40b that is the second attaching / detaching end part 4b are fitted and connected. The user may perform the work of making the core 4 an annular iron core. However, it cannot be said that it is a very efficient work for the user to perform accurate alignment between the first connecting portion 40a and the second connecting portion 40b by visual observation. Therefore, in the clamp sensor 2 according to the present embodiment, the first attachment / detachment end 4a side has the first attachment / detachment end 4a side so that the first attachment / detachment end 4a and the second attachment / detachment end 4b can be efficiently fitted and removed. The first connecting guide 6 is provided, and the second connecting guide 7 is provided on the second attaching / detaching end 4b side. The detailed structure of the 1st connection guide 6 and the 2nd connection guide 7 is demonstrated based on FIGS.

  In the connecting core 4, each basic link 40 is connected by the uniaxial joint connecting portion 43, so if the first attaching / detaching end portion 4 a and the second attaching / detaching end portion 4 b are brought close so as to close the connecting core 4, The first attaching / detaching end 4a and the second attaching / detaching end 4b naturally face each other in the vicinity. At this time, the 1st connection guide 6 and the 2nd connection guide 7 also oppose in the vicinity position (refer Fig.10 (a)). However, in order to accurately mesh the uneven shape of the first connecting portion 40a that is the first attaching / detaching end portion 4a and the uneven shape of the second connecting portion 40b that is the second attaching / detaching end portion 4b, finer alignment is required. It is.

  Therefore, the first connecting guide 6 and the second connecting guide 7 are introduced so that the first connecting portion 40a of the first attaching / detaching end portion 4a and the second connecting portion 40b of the second attaching / detaching end portion 4b are just fitted. A structure was provided. The first connection guide 6 is provided with a first introduction guide portion 62 and an operation ring 63 on the distal end side of the tube end holding portion 61 that holds one end portion of the coil holding tube 5. The second connection guide 7 is provided with a second introduction guide portion 72 on the distal end side of the tube end holding portion 71 that holds the other end portion of the coil holding tube 5. Then, the second introduction guide portion 72 in the second connection guide 7 is introduced into the introduction space formed between the first introduction guide portion 62 and the operation ring 63 in the first connection guide 6. That is, when the second introduction guide portion of the second connection guide 7 is introduced into the introduction space provided in the first connection guide 6, the first connection portion 40a of the first attachment / detachment end portion 4a and the second connection portion 2b of the second attachment / detachment end portion 4b. The position can be adjusted so that the connecting portion 40b is just fitted.

  First, the detailed structure of the first introduction guide portion 62 and the operation ring 63 in the first connection guide 6 will be described. The first introduction guide part 62 includes a fixed base 621 that is fixed to the tube end holding part 61 side, and a substantially rectangular frame-shaped inner connection introduction part 622 that protrudes from the fixed base 621 toward the distal end side. The first introduction guide portion 62 is formed with a first detachable end stationary space 62a penetrating from the fixed base 621 to the inner coupling introduction portion 622. The first detachable end stationary space 62a is connected to the first insertion guide portion 62a. The first detachable end 4a side is fixed. Further, for example, the front end side of the inner connection introducing portion 622 completely covers the first attachment / detachment end portion 4a of the connection core 4 and slightly protrudes from the front end portion of the operation ring 63. The earliest contact with the second connecting guide 7 will occur. Furthermore, the inner connection introduction part 622 has a four-side wall structure on the upper, lower, left and right sides close to the four sides of the connection core 4 having a substantially rectangular cross section. An introduction guide surface 62b that is inclined from the inner side (side facing the coupling core 4) to the outer side (side facing the operation ring 63) is formed on the distal end surface of each side wall portion of the inner coupling introduction portion 622. It is.

  The operation ring 63 is a cylindrical member having a size that can be easily operated by the user of the clamp meter 1 with a fingertip, and has a hollow inside. And the 1st introduction guide part so that the locking pieces 64 and 64 each provided in the appropriate place (for example, two places below and the lower part) of the inner peripheral surface 63a of the operation ring 63 can move only in the predetermined range to the inner peripheral direction. This is a structure that is rotatably held by a predetermined amount with respect to the fixed base portion 621 of 62. In a normal state, the operation ring 63 is attached in a predetermined direction by an urging member 55 (see FIGS. 12A and 12B) such as a coil spring so that the locking piece 64 stops at a predetermined reference position. It is energized. However, the urging force of the urging member 55 is stopped to such an extent that the user can rotate the operation ring 63 with his / her finger. Further, an introduction guide surface 63b in which the inner edge of the annular end surface is chamfered is provided on the distal end side of the operation ring 63.

  Next, the detailed structure of the second introduction guide portion 72 in the second connection guide 7 will be described. The second introduction guide portion 72 includes a fixed base portion 721 that is fixed to the tube end holding portion 71 side, and an outer connection introduction portion 722 that protrudes from the fixed base portion 721 toward the distal end side. The second introduction guide portion 72 is formed with a second detachable end stationary space 72a penetrating from the fixed base 721 to the outer connection introduction portion 722. The second detachable end stationary space 72a is connected to the second introduction guide portion 72a. The second detachable end 4b side is fixed. However, the second attachment / detachment end stationary space 72a is formed so that the inner connection introduction portion 622 of the first introduction guide portion 62 described above can be introduced, and the four inner walls and the connection core 4 that are the inner surfaces of the outer connection introduction portion 722. A space equal to the wall thickness of the inner connection introducing portion 622 is formed between the second detachable end portion 4b.

  As for the outer side surface of the second introduction guide portion 72, the peripheral peripheral fitting peripheral surface portion 722 a along the inner peripheral surface 63 a of the operation ring 63 is provided at two lateral sides, and the locking structure plane portion 722 b is provided at two upper and lower portions. It is the provided shape. The locking structure plane portion 722b forms an appropriate space so as not to prevent the locking piece 64 provided on the inner peripheral surface 63a of the operation ring 63 from moving within a predetermined range. A stopper piece 73 is provided near the front end side of the locking structure plane portion 722b toward one of the fitting peripheral surface portions 722a, and the locking piece 64 at the reference position is pressed against the stopper piece 73. . The stopper piece 73 is a projecting body that protrudes from the locking structure planar portion 722b in a range that does not contact the inner peripheral surface 63a of the operation ring 63. The stopper piece 73 is formed with a guide taper portion 73a that protrudes laterally so that the lock piece 64 at the reference position can come into contact with it, and a lock step portion 73b that is recessed with the guide taper portion 73a. As the guide taper portion 73a advances from the distal end side (side facing the first connection guide 6) close to one fitting peripheral surface portion 722a to the back side (side toward the fixed base portion 721), the other fitting peripheral surface portion The surface shape swells toward the 722a side. The locking step portion 73b has a surface shape that is depressed at once from the rear end where the guide taper portion 73a is interrupted toward the one of the fitting peripheral surface portions 722a again.

  A process of connecting the first attaching / detaching end portion 4a and the second attaching / detaching end portion 4b of the clamp sensor 2 by the first connecting guide 6 and the second connecting guide 7 configured as described above will be described. As described above, the introduction guide surface 62 b is provided on the front end surface of the four side walls of the inner connection introduction portion 622 that is the most distal portion of the first introduction guide portion 62 in the first connection guide 6. Due to the effect of the introduction guide surface 62b, the inner connection introduction portion 622 is smoothly guided to the second detachable end stationary space 72a of the outer connection introduction portion 722 that is the tip portion on the second connection guide 7 side. Further, the outer connection introduction portion 722 on the second connection guide 7 side is smoothly guided to the inner peripheral surface 63 a of the operation ring 63 by the introduction guide surface 63 b of the operation ring 63. At this time, the locking piece 64 protruding from the inner peripheral surface 63a of the operation ring 63 is pressed against the guide taper portion 73a of the stopper piece 73 provided in the second introduction guide portion 72 (FIG. 10B). (See FIGS. 11 (a), 12 (a), and 12 (c)).

  If the operation ring 63 is in a freely rotatable state (if the user does not hold it down by hand), the second connection guide 7 can be further pushed into the first connection guide 6. This is because the guide taper portion 73 a of the stopper piece 73 on the second connection guide 7 side is pressed against the locking piece 64, so that the locking piece 64 resists the biasing force of the biasing member 55 and the stopper piece 73. This is to move along the guide taper portion 73a. As the locking piece 64 moves, the operation ring 63 rotates in one direction (the α direction shown in FIGS. 10C and 12C). When the locking piece 64 reaches the rear end portion of the guide taper portion 73a of the stopper piece 73 (portion connected to the locking step portion 73b), the operation ring 63 does not rotate any more and the locking piece 64 is guided. The process proceeds further while being in sliding contact with the rear end of the tapered portion 73a. When the locking piece 64 completely exceeds the rear end portion of the guide taper portion 73a of the stopper piece 73, the operation ring 63 is moved to the other side (FIG. 10 (d) and FIG. 12 (d)) by the urging force of the urging member 55. In the β direction). Thereby, the locking piece 64 returns to the reference position along the locking step 73 b of the stopper piece 73. At this time, the first detachable end portion 4 a in the first connection guide 6 and the second detachable end portion 4 b in the second connection guide 7 are in a connected state in which all the connection ports 416 are just overlapped with each other. An iron core is formed.

  Note that, in the connected state of the first connecting guide 6 and the second connecting guide 7, the tip of the first introduction guide portion 62 in the first connecting guide 6 is the second detachable end portion stationary empty portion 72 a in the second connecting guide 7. It has almost reached the innermost part. Further, in the connected state of the first connection guide 6 and the second connection guide 7, the tip of the second introduction guide portion 72 in the second connection guide 7 almost reaches the fixed base 621 in the first connection guide 6. Therefore, in the connected state of the first connecting guide 6 and the second connecting guide 7, the second connecting guide 7 cannot be pushed further into the first connecting guide 6. Moreover, since the locking piece 64 has returned to the reference position at this time, the locking step portion 73b of the stopper piece 73 in the second connection guide 7 is on the rear side (side toward the fixed base portion 621). The second connection guide 7 cannot be pulled out from the first connection guide 6 as it is. That is, the locking piece 64 in the first connection guide 6 is locked to the locking step 73 b of the stopper piece 73 in the second connection guide 7, and the first connection guide 6 and the second connection guide 7 cannot be pulled out as they are. It is. However, if the user rotates the operation ring 63 in the α direction to disengage the locking piece 64 from the locking step portion 73b of the stopper piece 73, the first connection guide 6 and the second connection guide 7 can be easily moved. Can be removed.

  As described above, it is effective to use the first connection guide 6 and the second connection guide 7 in order to attach and detach the first attachment / detachment end 4a and the second attachment / detachment end 4b of the connection core 4. If the positioning function and the attachment / detachment function that can be realized by the first connection guide 6 and the second connection guide 7 are used, the first connection portion 40a that has a very dense uneven fitting structure by stacking the base material 41, The second connecting portion 40b can be easily connected or removed.

  An example of use of the clamp meter 1 according to the present embodiment configured as described above is shown in FIG. By simply removing the first connection guide 6 and the second connection guide 7 of the clamp sensor 2 and connecting the first connection guide 6 and the second connection guide 7 while surrounding the power pole 9, the entire power pole 9 can be clamped. Thus, it is possible to easily measure the ground current Ie and the leakage current Ir of the utility pole 9. In addition, unlike a Rogowski clamp sensor, it is possible to measure a minute current of about 0.5 mA to 5 mA. Moreover, even when three electric wires are separated by a switchboard in a three-phase three-wire circuit, according to the clamp meter 1 according to the present embodiment, the three separated electric wires are collectively collected by the clamp sensor 2. Since it can be clamped, a minute leakage current in the circuit can be measured. Furthermore, even with a three-phase three-wire thick lead wire parallel to the utility pole, according to the clamp meter 1 according to the present embodiment, these lead wires can be collectively clamped to measure a minute leakage current. .

  The embodiments of the clamp sensor according to the present invention and the clamp meter using the clamp sensor have been described with reference to the accompanying drawings. However, the present invention is not limited to this embodiment, and may be carried out by diverting known equivalent technical means within a range not changing the configuration described in the claims.

DESCRIPTION OF SYMBOLS 1 Clamp meter 2 Clamp sensor 3 Measuring apparatus 4 Connection core 4a 1st attachment / detachment edge part 4b 2nd attachment / detachment edge part 40 Basic link 40a 1st connection part 40b 2nd connection part 43 Uniaxial joint connection part 5 Coil holding tube 5a Core Insertion part 51 Inner layer tube 52 Coil 521 Magnet wire 53 Coil body 54 Outer layer tube

Claims (4)

A clamp sensor comprising a connecting core that is an annular iron core that surrounds a detected wire in a non-contact manner by connecting both ends, and a coil body that can arrange a coil on the outer periphery of the connecting core,
The connection core is formed of a high magnetic permeability soft magnetic material, and uses a plurality of connection elements each having a first connection portion and a second connection portion at a pair of end portions that are the most separated from each other, By connecting the second connecting part so as to be a rotatable uniaxial joint, a connecting structure in which both ends are opened is formed as a daisy chain, and the first connecting part is not connected in the connecting element body at one end. The first detachable end portion, the second linking portion which is not connected in the connecting element body at the other end as the second detachable end portion, and connecting the first detachable end portion and the second detachable end portion, It is possible to construct an annular iron core in which all connecting elements are closed in a ring,
The coil body has an inner space part into which the connecting core can be inserted, and has a length that allows the first attaching / detaching end part and the second attaching / detaching end part of the connecting core to be exposed from each end part. A flexible inner layer tube that can be deformed without difficulty following the deformation of the core, and a coil formed by winding a magnet wire around the outer surface of the inner layer tube,
A clamp sensor characterized in that an outer surface side of the coil body is covered with an insulating outer layer tube, and a connecting core is inserted in an inner space of the coil body. The connecting element body of the connecting core is configured to have a required thickness by laminating a plurality of base materials, which are plate materials of high permeability soft magnetic material,
The base material has a convex end edge projecting in an arc shape that is equidistant from an axial position connected so as to be a uniaxial joint at one end, and a circle with a curvature comparable to that of the projecting end edge. The other end side is provided with a concave edge that is recessed in an arc shape,
By forming the connection element body by alternately stacking the convex edge portion and the concave edge portion of the base material, the first connection portion and the second connection portion are the convex edge portion and the concave edge portion. The base material of each connecting element connected by a uniaxial joint rotates within the required range without obstructing each other's convex edge and concave edge. The clamp sensor according to claim 1, wherein the clamp sensor can be made.   3. An introduction guide portion for guiding the first attachment / detachment end portion and the second attachment / detachment end portion to a required fitting position is provided at each of both end portions. Clamp sensor. The clamp sensor according to any one of claims 1 to 3, comprising:
A clamp meter comprising a measuring device for calculating a current value to be measured from a detection signal obtained from a coil of the clamp sensor.

Images