JP7032130B2 - Clamp sensor and measuring device - Google Patents

Description

The present invention relates to a clamp sensor and a measuring device for detecting an amount to be detected for a measurement target.

Patent Document 1 discloses a measuring device including a clamp sensor in which a pair of clamp arms are formed in an annular shape, and a device main body to which the clamp sensor is openably and closably attached.

Japanese Patent No. 4077926

In the above-mentioned clamp sensor, since the annular shape of the pair of clamp arms is formed in a substantially perfect circle, each of the clamp arms is curved outward from the main body of the device even when the clamp sensor is closed. It has become.

Therefore, when the clamp sensor is opened, the opening width near the central portion of the clamp arm becomes large. Therefore, if the distance between the measurement target and other members adjacent to it is narrow, the clamp arm may come into contact with the other members and the measurement target may not be clamped when the measurement target is clamped by the clamp sensor. ..

Therefore, in order to make it easier to insert the clamp arm even in a narrow space where the clamp arm comes into contact with other members, the shape of the tip side of the clamp sensor is sharpened so that the central portion of the clamp arm when the clamp sensor is opened. It is conceivable to reduce the opening width in the vicinity. However, when the clamp sensor has a sharp shape, the tip of the coil body housed in the clamp arm tends to face outward, so that when the clamp sensor is closed, the gap between the tips of the coil bodies becomes large, and the clamp is clamped. There is a risk that the detection accuracy of the sensor will decrease.

The present invention has been made by paying attention to such a problem, and an object of the present invention is to make it easy to insert the clamp arm even in a narrow space and to suppress a decrease in the detection accuracy of the clamp sensor. ..

According to an aspect of the present invention, the clamp sensor that detects the detected amount for the measurement target with the pair of clamp arms closed is a pair of coil bodies that detect the detected amount and the pair of coil bodies. It is provided with a pair of clamp arms for accommodating each. The pair of clamp arms has a straight portion extending in parallel with each other and formed in a straight line, and a curved portion in which the tip portions thereof can be brought into contact with each other and curved from the straight portion toward the tip portion. The curved portion is formed so that the curvature on the straight portion side is smaller than the curvature on the tip portion side, and the tip portion of the coil body housed in the curved portion is bent inward by the bending means. ..

According to this aspect, since the pair of clamp arms has a pointed shape having a straight portion and a curved portion, it is easy to insert the clamp arm even in a narrow space. Further, since the tip portion of the coil body is bent inward by the bending means and accommodated in the clamp arm, the gap between the tip surfaces of the coil bodies accommodated in the pair of clamp arms can be reduced. Therefore, it is possible to prevent the detection accuracy of the clamp sensor from deteriorating.

FIG. 1 is a perspective view showing a measuring device including a clamp sensor according to the first embodiment of the present invention. FIG. 2A is a front view showing the shape of a pair of clamp arms constituting the clamp sensor. FIG. 2B is a diagram showing an internal structure of a pair of clamp arms. FIG. 3 is a perspective view of a pair of clamp arms. 4A and 4B are schematic cross-sectional views in a state where the concave portion and the convex portion of the clamp arm are fitted, FIG. 4A is a diagram showing the present embodiment, and FIG. 4B is a diagram showing a comparative example. Is. FIG. 5A is a cross-sectional view taken along the line II shown in FIG. 2A. FIG. 5B is a cross-sectional view taken along the line II-II shown in FIG. 2A. FIG. 6 is a diagram showing an assembly method of a coil body constituting the clamp sensor. FIG. 7 is a front view of the measuring device with the clamp sensor open. FIG. 8 is a diagram showing a state in which an electric wire is clamped by a clamp sensor and measured. FIG. 9 is a diagram showing a configuration of a coil body of a clamp sensor according to the second embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(First Embodiment)
FIG. 1 is an external perspective view showing an example of a measuring device 10 according to the first embodiment of the present invention.

The measuring device 10 includes a device main body 1 and a clamp sensor 2 supported by the device main body 1. The measuring device 10 measures the measured amount based on the detected amount of the measurement target detected by the clamp sensor 2. In the present embodiment, the detected amount includes the value of voltage, current or power generated in the clamp sensor 2, and the measured amount includes the value of AC current or AC power flowing through the measurement target and the value of AC power generated in the measurement target. Examples include the value of voltage or resistance, or the value of the magnetic field generated from the measurement target.

The device main body 1 calculates and displays the measured quantity according to the operation of the user, and has a built-in arithmetic processing device as a measuring unit that measures the measured quantity based on the detection signal output from the clamp sensor 2. Has been done. Further, the apparatus main body 1 is used to open / close the liquid crystal display unit 11 that displays the measured quantity, the operation buttons 12 and the operation dial 13 used for setting the measurement contents and the display contents, and the clamp sensor 2. The opening / closing lever 14 used is provided. The opening / closing lever 14 is urged by a spring in the direction of closing the clamp sensor 2.

The clamp sensor 2 clamps the measurement target and detects the detected amount of the measurement target. The clamp sensor 2 includes a pair of clamp arms 21 and 22 that are rotatably attached to the apparatus main body 1 so that the tip portions 231 and 232 of each other can be brought into contact with each other.

If the opening / closing lever 14 is not pushed, the clamp sensor 2 is maintained in a closed state in which the tip portions 231,232 of the pair of clamp arms 21 and 22 are in contact with each other. On the other hand, in the clamp sensor 2, when the opening / closing lever 14 is pushed by the user, the tip portions 231 and 232 of the pair of clamp arms 21 and 22 are opened apart from each other.

The clamp sensor 2 detects the detected amount for the measurement target in the closed state. The measurement target referred to here is a portion or member surrounded by both the clamp arms 21 and 22 and for which the detected amount is measured, and is, for example, an electric wire.

Next, the structure of the clamp sensor 2 will be described with reference to FIGS. 2A and 2B.

FIG. 2A is a diagram showing a state in which the clamp sensor 2 is closed.

The clamp sensor 2 is formed in an annular shape as a whole in the closed state. Specifically, the clamp sensor 2 is formed in a pointed shape as a whole so that it can be easily inserted into a narrow space. Each of the clamp arms 21 and 22 is formed in a substantially bow shape and has substantially the same shape.

Chamfered curved surfaces 21c and 22c are formed on the outer peripheral surfaces of the clamp arms 21 and 22. The specific shape of the outer peripheral surface of the clamp arms 21 and 22 will be described later with reference to FIGS. 5A and 5B.

Each of the clamp arms 21 and 22 has a base portion 210 and 220 close to the rotation fulcrum, a straight portion 211 and 221 formed in a straight line, and a curved portion 212 and 222 curved toward the tip portions 231 and 232, respectively. Has.

The pair of bases 210 and 220 are arranged so that their ends 201 and 202 can be brought into contact with each other as the clamp arms 21 and 22 rotate.

Support portions 250 and 260 projecting toward the apparatus main body 1 are formed on the outer peripheral surfaces of the base portions 210 and 220, respectively. Holes 25 and 26 are formed in the support portions 250 and 260, and pins provided in the apparatus main body 1 are inserted into the holes 25 and 26. The support portions 250 and 260 are rotatably supported by the apparatus main body 1 via pins, and the clamp arms 21 and 22 rotate around the pins.

The pair of straight portions 211 and 221 are formed so that the outer surfaces 211a and 221a, which are the outer side surfaces of the outer peripheral surfaces of the clamp arms 21 and 22, extend in parallel with each other when the clamp sensor 2 is closed. Will be done. Thereby, the opening width of the middle portion of the clamp arms 21 and 22 when the user opens the clamp sensor 2 can be narrowed.

In the present embodiment, the lengths Ls of the outer surfaces 211a and 221a of the straight portions 211 and 221 are formed so as to be 30% to 40% with respect to the total length Lt of the clamp sensor 2.

The pair of curved portions 212 and 222 are formed so that the tip portions 231 and 232 can be brought into contact with each other and the clamp sensor 2 has a pointed shape. The curved portions 212 and 222 are formed so that the curvature of the outer surface on the straight portion 211,221 side is smaller than the curvature of the outer surface on the tip portions 231,232 side.

For example, the curvature of the outer surface of the curved portions 212 and 222 is formed to be smaller than the reference curvature from the straight portions 211,221 to the tip portions 231 and 232, and is formed to be larger than the reference curvature thereafter. The reference curvature referred to here is the curvature of a perfect circle whose diameter is the length between the outer surface 211a of the straight portion 211 and the outer surface 221a of the straight portion 221 when the clamp sensor 2 is closed. be.

Further, the curvature of the outer surface of the curved portions 212 and 222 may be increased as it approaches the tip portions 231 and 232, or may be set to a constant value smaller than the reference curvature from the straight portions 211 and 221 to the middle. After that, it may be a constant value larger than the reference curvature.

As shown in FIG. 3, a concave portion 213 is formed in the tip portion 231 of the curved portion 212, and a convex portion 223 is formed in the tip portion 232 of the curved portion 222. By fitting the convex portion 223 into the concave portion 213, the tip portions 231,232 of the clamp arms 21 and 22 are prevented from coming off when the clamp sensor 2 is closed. The details of the fitting structure of the concave portion 213 and the convex portion 223 will be described later with reference to FIG.

FIG. 2B is a front view showing the internal structure of the clamp arms 21 and 22 in a state where the clamp sensor 2 is closed.

The clamp arms 21 and 22 each accommodate a pair of coil bodies 3 for detecting the amount to be detected for the measurement target. Each of the clamp arms 21 and 22 is divided and formed by two members, and FIG. 2B shows a state in which one member is removed.

When the shape of the clamp sensor 2 is formed to be a pointed shape, the tip end side of the coil body 3 housed in the clamp arms 21 and 22 tends to face outward. Therefore, if no measures are taken, the gap between the tip surfaces 3a of the pair of coil bodies 3 becomes large, and the detection accuracy of the clamp sensor 2 deteriorates.

As a countermeasure, in the present embodiment, the curved portion 212 of the clamp arm 21 is provided with a rib 215 as a pressing portion that applies pressure to the outer surface of the tip portion of the coil body 3 and presses the curved portion 212 toward the inner wall of the curved portion 212. It is formed.

The rib 215 has one end 215a coupled to the inner wall of the curved portion 212 and the other end 215b formed as a free end. The tip end portion of the coil body 3 is inserted between the other end portion 215b of the rib 215 and the inner wall of the curved portion 212. Since the gap between the other end portion 215b of the rib 215 and the inner wall of the curved portion 212 is formed to be slightly smaller than the diameter of the coil body 3, the gap between the other end portion 215b of the rib 215 and the inner wall of the curved portion 212 is formed. The tip end portion of the inserted coil body 3 is pressed toward the inner wall of the curved portion 212 by the rib 215. In this way, the tip end side of the coil body 3 is bent inward by the rib 215.

The curved portion 222 of the clamp arm 21 is also formed with a rib 225 having the same function as the rib 215, although the shape is different from that of the rib 215.

Therefore, when the clamp sensor 2 is closed, the tip ends of the pair of coil bodies 3 are bent inward by the ribs 215 and 225, respectively, so that the gap between the tip faces 3a of the pair of coil bodies 3 can be reduced. In this embodiment, the ribs 215 and 225 correspond to the bending means.

Further, the inner wall 216 of the curved portion 212 on which the tip end portion of the coil body 3 is pressed by the rib 215 is formed linearly. Similarly, the inner wall 226 of the curved portion 222 in which the tip end portion of the coil body 3 is pressed by the rib 225 is also formed linearly. Further, the inner wall 216 of the curved portion 212 and the inner wall 226 of the curved portion 222 are formed on the same straight line. As a result, when the clamp sensor 2 is closed, the tip surfaces 3a of the pair of coil bodies 3 pressed by the ribs 215 and 225 tend to face each other in parallel, further reducing the gap between the tip surfaces 3a. be able to.

The bases 210 and 220 of the clamp arms 21 and 22 are also formed with ribs 217 and 227 that apply pressure to the outer surface of the base end of the coil body 3 and press it toward the inner walls of the bases 210 and 220. .. The ribs 217 and 227 have the same function as the ribs 215 and 225. Since the ribs 217 and 227 are also formed on the bases 210 and 220 in this way, the gap between the base end surfaces 3b of the pair of coil bodies 3 can be reduced when the clamp sensor 2 is closed.

Next, the fitting structure of the concave portion 213 and the convex portion 223 formed in the tip portions 231 and 232 of the clamp arms 21 and 22 will be described with reference to FIGS. 3 and 4.

FIG. 3 is a perspective view showing the shapes of the concave portion 213 and the convex portion 223 formed on the tip portions 231 and 232.

As shown in FIG. 3, a concave portion 213 is formed in the tip portion 231 of the curved portion 212, and a convex portion 223 is formed in the tip portion 232 of the curved portion 222.

The recess 213 is partitioned by a peripheral wall portion 213a that rises from the peripheral edge of the tip portion 231 of the curved portion 212. The outer peripheral surface of the peripheral wall portion 213a is formed continuously with the outer peripheral surface of the curved portion 212. The peripheral wall portion 213a is cut out from the inside of the curved portion 212, whereby the open portion 213b is formed in the recess 213. The open portion 213b is formed continuously and flatly with the tip portion 231.

The convex portion 223 is formed so as to project from the tip portion 232 of the curved portion 222. The convex portion 223 has a fitting portion 223a having an outer peripheral surface along the inner peripheral surface of the peripheral wall portion 213a for partitioning the concave portion 213, and an extending portion 223b inserted into the open portion 213b of the concave portion 213. The end faces of the fitting portion 223a and the extending portion 223b are continuously and flatly formed.

In the state where the clamp sensor 2 is closed, the convex portion 223 is fitted in the concave portion 213, and the extended portion 223b of the convex portion 223 is inserted into the open portion 213b of the concave portion 213. In this state, the end surface of the convex portion 223 abuts on the tip portion 231 of the curved portion 212, and the end surface of the peripheral wall portion 213a of the concave portion 213 faces the tip portion 232 of the curved portion 222. By fitting the convex portion 223 into the concave portion 213 in this way, the tip portions 231 and 232 of the clamp arms 21 and 22 are prevented from coming off when the clamp sensor 2 is closed.

Further, a pair of groove portions 213c arranged to face each other are formed on the inner peripheral surface of the peripheral wall portion 213a. Further, a pair of protrusions 223c that fit into the pair of groove portions 213c are formed on the outer peripheral surface of the convex portion 223. By fitting the protrusion 223c into the groove 213c, the protrusion 223 is prevented from coming out of the recess 213 through the opening portion 213b, so that the tip portions 231,232 of the clamp arms 21 and 22 are more effectively prevented from coming off. ..

Further, since the convex portion 223 has an extended portion 223b inserted into the open portion 213b of the concave portion 213, the tip surface of the coil body 3 housed in the clamp arms 21 and 22 in a state where the clamp sensor 2 is closed. The interval of 3a can be reduced. The reason for this will be described in detail with reference to FIG.

4A and 4B are schematic cross-sectional views in a state where the concave portion 213 and the convex portion 223 of the clamp arms 21 and 22 are fitted, FIG. 4A is a diagram showing the present embodiment, and FIG. 4B is a diagram showing the present embodiment. It is a figure which shows the comparative example. The corresponding configurations are labeled with the same reference numerals.

In the comparative example shown in FIG. 4B, the peripheral wall portion 213a for partitioning the concave portion 213 has an annular shape, and the entire outer peripheral surface of the convex portion 223 is fitted to the inner peripheral surface of the concave portion 213. That is, the concave portion 213 does not have the open portion 213b of the present embodiment, and the convex portion 223 does not have the extended portion 223b of the present embodiment.

As shown in FIG. 4B, in the comparative example, since the entire outer peripheral surface of the convex portion 223 fits into the inner peripheral surface of the concave portion 213, it is necessary to reduce the outer shape of the convex portion 223, which corresponds to this. As a result, the space S1 in the convex portion 223 is also narrowed. If the coil body 3 cannot be accommodated in the space S1 in the convex portion 223 as in this example, the distance between the tip surfaces 3a of the coil bodies 3 accommodated in the clamp arms 21 and 22 becomes large. ..

On the other hand, as shown in FIG. 4A, in the present embodiment, since the convex portion 223 has an extended portion 223b inserted into the open portion 213b of the concave portion 213, the convex portion 223 is inside the convex portion 223 as compared with the comparative example. The space S1 is widened by the extension portion 223b. Therefore, the coil body 3 housed in the clamp arm 22 can be housed in the space S1 in the convex portion 223. As a result, the distance between the tip surfaces 3a of the coil bodies 3 housed in the clamp arms 21 and 22 can be reduced.

Next, the shape of the outer peripheral surface of the clamp arms 21 and 22 will be described with reference to FIGS. 5A and 5B. FIG. 5A is a cross-sectional view taken along the line II shown in FIG. 2A. FIG. 5B is shown in FIG. 2A.
It is sectional drawing along the line II-II shown in.

The clamp arm 22 has a substantially rectangular cross-sectional shape, and the corners of the outer peripheral surface are chamfered. Therefore, as shown in FIG. 2A, a curved surface 22c is formed on the outer peripheral surface of the clamp arm 22. The chamfered amount of the corner portion of the outer peripheral surface of the clamp arm 22 is not constant, and the corner portion is chamfered so that the curvature of the corner portion decreases toward the tip portion 232. Specifically, as shown in FIG. 5A, the chamfered amount of the corner portion of the straight portion 221 is small, and the cross-sectional shape of the straight portion 221 is a substantially rectangular shape having four corner portions. As a result, the strength of the clamp arm 22 on the device main body 1 side can be increased. On the other hand, as shown in FIG. 5B, the chamfered amount of the corner portion of the curved portion 222 is large, and the cross-sectional shape of the curved portion 222 is a shape close to a circle.

As described above, the curvature of the corner portion of the curved portion 222 is formed to be smaller than the curvature of the corner portion of the straight portion 221. As a result, the clamp arm 22 is formed so that the cross-sectional shape on the tip side approaches a circular shape. The same chamfer is made on the corners of the outer peripheral surface of the clamp arm 21, and the curved surface 21c is also formed on the clamp arm 21. Therefore, when the measuring portion is clamped by the clamp sensor 2, the outer peripheral surfaces of the clamp arms 21 and 22 are prevented from being caught by other members such as electric wires and storage plates adjacent to the measuring portion, and the clamp sensor 2 is narrowed. It will be easier to insert into the space.

As described above, since the curvature of the corners of the outer peripheral surfaces of the clamp arms 21 and 22 is formed to be smaller toward the tip portions 231 and 232, the clamp arm 21 and the clamp arm 21 on the device main body 1 side of the clamp sensor 2 The strength of 22 can be ensured, and the clamp arms 21 and 22 can be easily inserted on the tip side.

Further, as can be seen from FIGS. 5A and 5B, the curvature of the outer corner portion of the outer peripheral surface of the clamp arms 21 and 22 is smaller than the curvature of the inner corner portion. As a result, it becomes difficult for the outside of the clamp arms 21 and 22 to be caught by other members adjacent to the measurement target, and it becomes easy to support the measurement target inside the clamp arms 21 and 22.

Next, the coil body 3 housed in the clamp arms 21 and 22 will be described with reference to FIG. FIG. 6 is a diagram illustrating an example of a method of assembling the coil body 3 housed in the clamp arms 21 and 22.

First, as shown in FIG. 6A, the flexible member 31 is prepared. The flexible member 31 is a hollow member having an insulating property, and is made of a synthetic resin such as vinyl chloride or polyethylene. As the flexible member 31 of the present embodiment, vinyl chloride, which is softer than polyethylene, is used.

Then, as shown in FIG. 6B, the coil 32 is wound around the flexible member 31 by using an automatic winding machine. The coil 32 of the present embodiment is wound in multiple layers so as to have two or more layers, preferably three or more layers. The number of turns of the coil 32 may be increased on both ends of the flexible member 31 as compared with other parts. Thereby, it is possible to compensate the detection sensitivity of the missing portion where the coil 32 does not exist in the tip portions 231 and 232 of the clamp arms 21 and 22 and the end portions 201 and 202 of the base portions 210 and 220.

Next, as shown in FIG. 6 (c), when the winding of the coil 32 around the flexible member 31 is completed, in order to prevent the coil 32 from unwinding, both ends of the flexible member 31 are wound. The cap 30 is inserted. As described above, the coil body 3 has the flexible member 31, the coil 32, and the cap 30, and is subjected to multi-layer winding by the automatic winding machine. Therefore, the coil body 3 has characteristics similar to those of the so-called Rogowski coil. Has.

Finally, as shown in FIG. 6D, the coil body 3 is bent and accommodated along the inner walls of the clamp arms 21 and 22. In this way, by using the flexible member 31, it is possible to bend the tip end side of the coil body 3 inward by the ribs 215 and 225 formed on the clamp arms 21 and 22.

Next, the usage mode of the clamp sensor 2 will be described with reference to FIGS. 7 and 8.

FIG. 7 is a front view showing a state in which the opening / closing lever 14 is pushed by the user and the clamp sensor 2 is opened. As shown in FIG. 7, since the pair of clamp arms 21 and 22 have straight portions 211 and 221 so that the clamp arms 21 have the same length and are substantially circular as compared with the clamp sensor. , 22 can be narrowed. The opening width here is the largest width among the widths between the clamp arms 21 and 22 when the clamp arms 21 and 22 are opened.

Further, the curved portions 212 and 222 are formed so that the curvature of the outer surface on the straight portion 211,221 side is smaller than the curvature of the outer peripheral surface on the tip portion 231,232 side, so that the clamp sensor 2 has a sharp shape. It is formed. Therefore, the opening width, which is the width between the tip portions 231,232 of the clamp arms 21 and 22 when the clamp sensor 2 is open, can be increased.

In this way, the clamp arms 21 and 22 have a pair of curved portions 212 and 222 in addition to the pair of straight portions 211 and 22 so that when the clamp sensor 2 is opened, the opening width of the clamp arms 21 and 22 can be increased. The opening width of the tip portions 231 and 232 can be secured while narrowing.

FIG. 8 is a front view showing a state in which the clamp sensor 2 is closed. Here, it is assumed that the user measures the alternating current flowing through the electric wire 102 by using the measuring device 10 in a situation where the thick electric wires 101 to 103 are laid vertically at narrow intervals.

When the measurement target is a thick electric wire 102, it is necessary to open the clamp sensor 2 with a large opening width in order to clamp the electric wire 102. However, when the distance between the electric wire 102 to be measured and the electric wires 101 and 103 adjacent thereto is narrow, when the clamp sensor 2 is opened with a large opening width, the clamp sensor 2 is opened between the electric wires 102 and 101 and with the electric wire 102. It becomes difficult to insert it between 103.

Even in such a situation, the clamp sensor 2 of the present embodiment has the tip portions 231,232 while narrowing the opening width of the clamp arms 21 and 22 when the clamp sensor 2 is opened as described above. As shown in FIG. 8, the clamp arm can be inserted by the user by simply inserting the clamp arms 21 and 22 horizontally or by tilting the clamp arm 21 and 22 with respect to the horizontal plane. 21 and 22 make it possible to surround the electric wire 102.

The effects of the above-mentioned first embodiment will be described below.

According to the present embodiment, the clamp sensor 2 detects the detected amount to be measured with the pair of clamp arms 21 and 22 closed. The clamp sensor 2 includes a pair of coil bodies 3 for detecting an amount to be detected with respect to a measurement target, and a pair of clamp arms 21 and 22 for accommodating the pair of coil bodies 3, respectively.

A pair of clamp arms 21 and 22 have straight portions 211 and 221 extending in parallel with each other and formed in a straight line. Further, it has curved portions 212 and 222 that are detachable from each other and are curved from the straight portions 211 and 221 toward the tip portions 231 and 232.

The curved portions 212, 222 are formed so that the curvature on the straight portion 211,221 side is smaller than the curvature on the tip portions 231,232 side, and the tip portion of the coil body 3 housed in the curved portions 212, 222 is bent. It can be bent inward by means.

As described above, the pair of clamp arms 21 and 22 have straight portions 211 and 221 extending in parallel with each other when the clamp sensor 2 is closed. As a result, when the clamp sensor 2 is opened, the opening width of the pair of clamp arms 21 and 22 in the middle portion can be narrowed.

Further, since the curvatures of the curved portions 212 and 222 are formed so that the curvature on the straight portion 211,221 side is smaller than the curvature on the tip portions 231,232 side, the shape on the tip side of the clamp sensor 2 can be sharpened.

Therefore, the opening width of the middle portion of the clamp sensor 2 is narrowed, and the shape of the clamp sensor 2 is sharp, so that the clamp arms 21 and 22 can be easily inserted even in a place where the space between the members is narrow. can do.

On the other hand, due to the pointed shape of the clamp sensor 2, the tip end side of the coil body 3 housed in the clamp arms 21 and 22 tends to face outward. Therefore, the distance between the tip surfaces 3a of the coil body 3 is widened, and the detection accuracy of the clamp sensor 2 tends to decrease. Further, as shown in FIG. 8, due to the pointed shape of the clamp sensor 2, the electric wire 102 clamped by the clamp sensor 2 is measured in the vicinity of the top portion 23 of the clamp sensor 2. is assumed.

Generally, the closer the electric wire 102 is to the top 23 of the clamp sensor 2, the stronger the magnetic field passing through the gap between the tip surfaces 3a of the coil body 3 at the top 23. As a result, when the measurement is performed at a position where the electric wire 102 comes into contact with the top portion 23, the magnetic field generated from the electric wire 102 is the strongest in the place where the coil body 3 does not exist, so that the magnetic field is generated in the entire pair of coil bodies 3. The amount of voltage drop will also be large. Therefore, as the electric wire 102 approaches the top portion 23, the voltage generated in the pair of coil bodies 3 is lower than the original value, so that the detection accuracy of the clamp sensor 2 is lowered.

Regarding this point, in the present embodiment, the tip end portion of the coil body 3 housed in the curved portions 212 and 222 is bent inward by the bending means, and when the clamp sensor 2 is closed, the top portion 23 of the clamp sensor 2 is used. The tip surfaces 3a of the pair of coil bodies 3 are made easy to face each other. As a result, the gap between the tip surfaces 3a of the coil body 3 at the top 23 of the clamp sensor 2 can be narrowed, and the deterioration of the detection accuracy of the clamp sensor 2 due to the pointed shape of the clamp sensor 2 is suppressed. can do.

Therefore, according to the present embodiment, it is possible to easily insert the clamp arms 21 and 22 into a narrow space and to prevent the detection accuracy of the clamp sensor 2 from deteriorating.

Further, in the present embodiment, as shown in FIG. 2B, the bending means bends the tip portion of the coil body 3 in a straight line, and the tip portions of the pair of coil bodies 3 are mutually bent in a state where the clamp sensor 2 is closed. Arranged on the same straight line. As a result, the tip surfaces 3a of the pair of coil bodies 3 face each other, so that the distance between the tip surfaces 3a can be further narrowed.

Further, as shown in FIG. 2B, the bending means is a rib 215, 225 as a pressing portion that applies pressure to the outer peripheral surface of the tip portion of the coil body 3 and presses it toward the inner wall of the curved portions 212, 222. It is composed. According to this configuration, in addition to being able to easily bend the tip of the coil body 3 housed in the curved portions 212 and 222 inward, the coil body 3 is formed on the curved portions 212 and 222 by utilizing the ribs 215 and 225. The work of accommodating the coil becomes easier.

Further, as shown in FIG. 2B, the inner walls 216 and 226 of the curved portions 212 and 222 on which the tip portions of the coil bodies 3 are pressed by the ribs 215 and 225 are formed linearly. Further, the inner walls 216 and 226 are formed on the same straight line when the clamp sensor 2 is closed. As a result, it is possible to prevent the tip portions of the pair of coil bodies 3 from bending too much inward, and to make the tip faces 3a parallel to each other. Therefore, the gap between the tip surfaces 3a can be further reduced.

Further, in the present embodiment, the cross-sectional shape of the clamp arms 21 and 22 is formed in a substantially rectangular shape as shown in FIGS. 5A, and further, as shown in FIGS. 2A and 5B, the outer peripheral surface of the clamp arms 21 and 22 is formed. The corners formed in the above are formed so that the curvature becomes smaller toward the tip portions 231 and 232. This makes it possible to easily insert the clamp arms 21 and 22 into a narrow space while improving the strength of the clamp arms 21 and 22.

Further, in the present embodiment, as shown in FIG. 3, a convex portion 223 is formed at the tip portion 232 of the curved portion 222, and a concave portion 213 into which the convex portion 223 fits is formed at the tip portion 231 of the curved portion 212. To. Further, in the concave portion 213, an open portion 213b is formed inside the curved portion 212, the convex portion 223 has an extended portion 223b inserted into the open portion 213b, and the tip portion of the coil body 3 has a convex portion 223. It is housed in the space S1 inside. According to this configuration, the space S1 in the convex portion 223 is widened by the amount of the extending portion 223b, and the coil body 3 accommodated in the clamp arm 22 can be accommodated in the space S1 in the convex portion 223. Therefore, the distance between the tip surfaces 3a of the coil bodies 3 housed in the clamp arms 21 and 22 can be further reduced.

Further, in the present embodiment, as shown in FIG. 1, the measuring device 10 is a measuring unit that measures a measured amount for a measurement target based on a clamp sensor 2 and a measured amount detected by the clamp sensor 2. It is provided with a device main body 1 having a built-in device. As a result, the alternating current flowing through the measurement target can be measured based on the magnitude of the voltage generated in the clamp sensor 2.

(Second Embodiment)
In the first embodiment, the embodiment in which the bending means is the ribs 215 and 225 formed on the curved portions 212 and 222 has been described. In the second embodiment, the bending means is formed on the flexible member 31 of the coil body 3. This will be described in detail below.

FIG. 9 is a diagram showing the configuration of the coil body 3 of the clamp sensor according to the second embodiment of the present invention.

In the present embodiment, as the flexible member 31 of the coil body 3, a member having a certain degree of hardness, for example, polyethylene harder than vinyl chloride is used.

As shown in FIG. 9, a notch 311 is formed on the outer peripheral surface of the flexible member 31. Specifically, the notch 311 is formed on the end side of the flexible member 31.

When accommodating the pair of coil bodies 3 in the clamp arms 21 and 22, the pair of coil bodies 3 are bent so as to follow the shape of the clamp arms 21 and 22 and the tip surfaces 3a of each other face each other. The tip is bent. When bending the tip portion of the coil body 3, as shown in FIG. 9, the coil body 3 is bent with the notch 311 formed in the flexible member 31 as a boundary.

By forming the notch 311 on the outer peripheral surface of the coil body 3 in this way, the tip of the coil body 3 can be easily bent inward and tries to return to the original shape of the flexible member 31. The restoring force can be reduced to maintain the bent state. That is, the notch 311 corresponds to a bending means for bending the tip end portion of the coil body 3 inward.

In the present embodiment, the ribs 215 and 225 formed on the curved portions 212 and 222 described in the first embodiment can be omitted. By forming the notch 311 on the outer peripheral surface of the flexible member 31, the tip portion of the coil body 3 housed in the clamp arms 21 and 22 can be bent inward even if the ribs 215 and 225 are omitted.

According to the present embodiment, the coil body 3 has an insulating flexible member 31 and a coil 32 wound around the flexible member 31, and is cut into the outer peripheral surface of the flexible member 31. 311 is formed. This makes it possible to bend the tip end portion of the coil body 3 housed in the clamp arms 21 and 22 inward. Therefore, as in the first embodiment, the clamp arms 21 and 22 can be easily inserted into a narrow space, and the deterioration of the detection accuracy of the clamp sensor 2 can be suppressed.

In the present embodiment, an example in which a notch 311 is formed on the outer peripheral surface of the flexible member 31 instead of the ribs 215 and 225 formed on the curved portions 212 and 222 has been described, but the outer peripheral surface of the flexible member 31 has been described. In addition to forming the notch 311, ribs 215 and 225 may be formed in the curved portions 212 and 222.

Although the embodiments of the present invention have been described above, the above embodiments are only a part of the application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiments. do not have.

For example, in addition to the coil body 3, a voltage sensor, a temperature sensor, or a stoichiometry sensor may be accommodated in at least one of the clamp arms 21 and 22.

1 Device body 2 Clamp sensor 3 Coil body 10 Measuring device 21, 22 Clamp arm 21c, 22c Curved surface 211, 221 Straight part 212, 222 Curved part 213 Recessed part 215, 217, 225, 227 Ribs (bending means, pressing part)
223 Convex part 231, 232 Tip part 311 Notch (bending means)

Claims (8)

A clamp sensor that detects the amount to be detected for a measurement target with the pair of clamp arms closed.
A pair of coil bodies for detecting the amount to be detected, and
A pair of clamp arms for accommodating the pair of coil bodies, respectively, are provided.
The pair of clamp arms
A straight part that extends parallel to each other and is formed in a straight line,
It has a curved portion that is separable from each other and curves from the straight portion toward the tip portion.
The curved portion is formed so that the curvature on the straight portion side is smaller than the curvature on the tip portion side.
The tip portion of the coil body housed in the curved portion is bent inward by bending means, and is bent inward .
The coil body has a flexible member having an insulating property and a coil wound around the flexible member.
The bending means is a notch formed on the outer circumference of the flexible member.
Clamp sensor. A clamp sensor that detects the amount to be detected for a measurement target with the pair of clamp arms closed.
A pair of coil bodies for detecting the amount to be detected, and
A pair of clamp arms for accommodating the pair of coil bodies, respectively, are provided.
The pair of clamp arms
A straight part that extends parallel to each other and is formed in a straight line,
It has a curved portion that is separable from each other and curves from the straight portion toward the tip portion.
The curved portion is formed so that the curvature on the straight portion side is smaller than the curvature on the tip portion side.
The tip portion of the coil body housed in the curved portion is bent inward by bending means, and is bent inward .
The clamp arm has a substantially rectangular cross-sectional shape, and the curvature of the corner portion formed on the outer peripheral surface is formed to be smaller toward the tip portion.
Clamp sensor. A clamp sensor that detects the amount to be detected for a measurement target with the pair of clamp arms closed.
A pair of coil bodies for detecting the amount to be detected, and
A pair of clamp arms for accommodating the pair of coil bodies, respectively, are provided.
The pair of clamp arms
A straight part that extends parallel to each other and is formed in a straight line,
It has a curved portion that is separable from each other and curves from the straight portion toward the tip portion.
The curved portion is formed so that the curvature on the straight portion side is smaller than the curvature on the tip portion side.
The tip portion of the coil body housed in the curved portion is bent inward by bending means, and is bent inward .
A convex portion is formed on the tip portion of the curved portion, and a convex portion is formed.
A concave portion into which the convex portion fits is formed in the tip portion of the other curved portion.
In the concave portion, an open portion is formed inside the curved portion, and an open portion is formed.
The convex portion has an extension portion to be inserted into the open portion.
The tip portion of the coil body is accommodated in the space inside the convex portion.
Clamp sensor. The clamp sensor according to any one of claims 1 to 3 .
The bending means bends the tip of the coil body in a straight line.
The tips of the pair of coils are arranged on the same straight line.
Clamp sensor. The clamp sensor according to any one of claims 1 to 4 .
The bending means has a pressing portion that applies pressure to the outer surface of the tip end portion of the coil body and presses the pressure toward the inner wall of the curved portion.
Clamp sensor. The clamp sensor according to claim 5 .
The pressing portion is a rib formed on the curved portion.
Clamp sensor. The clamp sensor according to claim 5 or 6 .
The inner wall of the curved portion where the tip portion of the coil body is pressed by the pressing portion is formed in a straight line.
The inner wall of the curved portion of the pair of clamp arms is formed on the same straight line.
Clamp sensor. The clamp sensor according to any one of claims 1 to 7 .
A measuring device including a measuring unit for measuring a measured amount for the measurement target based on the detected amount detected by the clamp sensor.

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