JP6732563B2 - Sensors and current measuring devices - Google Patents

Description

The present invention relates to a sensor including a core surrounding a conductor and a detection element arranged at an end of the core, and a current measuring device including the sensor.

A clamp sensor disclosed by the applicant in Patent Document 1 below is known as a sensor of this type. This clamp sensor has a core cover and a magnetic core housed in the core cover, and is provided with a pair of sensor parts that form an annular shape when the tips are brought into contact with each other (clamped). ing. Further, a magnetoelectric conversion element is arranged at the tip of the magnetic core in one of the sensor units. In this clamp sensor, the magnetoelectric conversion element detects a magnetic field when the conductor to be measured in a live state is clamped by each sensor unit.

Japanese Patent Laid-Open No. 2000-180475 (Pages 2-4, FIGS. 1-3)

However, the above clamp sensor has the following problems to be improved. That is, in this clamp sensor, the magnetoelectric conversion element arranged at the tip of the magnetic core in one of the sensor sections detects the magnetic field. In other words, this clamp sensor is configured to detect the magnetic field with one magnetoelectric conversion element. In this case, the number of magnetic flux lines passing through the sensor section varies depending on the position of the measured conductor in the ring formed by the sensor section when the measured conductor is clamped. That is, in this clamp sensor, the sensitivity of the clamp sensor differs depending on the position of the conductor to be measured. Specifically, in this clamp sensor in which the magnetoelectric conversion element is arranged at the tip of the magnetic core (upper part of the ring), the measured conductor is placed on the upper side (end of the magnetic core) in the ring. The sensitivity of the clamp sensor increases when it is located, and conversely, the sensitivity of the clamp sensor when the conductor to be measured is located on the lower side (base end side of the magnetic core) in the ring. Becomes lower. In this case, a magnetoelectric conversion element is provided at both the tip and the base end of the sensor unit, and the value of the magnetic field detected by each magnetoelectric conversion element is adjusted to adjust in the vertical direction (to the tip side of the magnetic core. There is known a configuration (for example, a clamp sensor disclosed by the applicant in Japanese Patent Laid-Open No. 2003-43073) that corrects variation in sensitivity in the direction of connecting the base end side. On the other hand, in a conventional clamp sensor including this clamp sensor, a gap is formed between the opposite ends of each core in a state where the tip ends of the clamp parts are in contact with each other (clamped). Has been done. Further, in the conventional clamp sensor, the magnetoelectric conversion element is arranged so as to be close (or in close contact) to the tip portion (tip surface) of the core in one of the clamp portions. That is, in the conventional clamp sensor, the magnetoelectric conversion element is arranged in a state of being biased to either one of the two facing ends of each core. Therefore, in the conventional clamp sensor, variations in sensitivity occur in the left-right direction (direction orthogonal to the up-down direction), and as a result, it is difficult to further improve the accuracy, and improvement in this point is desired.

The present invention has been made in view of such problems to be improved, and a main object of the present invention is to provide a sensor and a current measuring device capable of improving detection accuracy.

In order to achieve the above object, the sensor according to claim 1 has a core configured such that the respective end portions face each other in a state in which a gap is generated between the respective end portions in a state of surrounding a conductor to be detected, a sensor having a detecting element for detecting the detected amount generated in the core when a current flows through the conductor is disposed on one of the respective end portions facing each other, a non-magnetic material A spacer that is formed and is arranged between any one of the ends and the detection element, and positions the detection element in the center of the gap so that the distances to the opposite ends are equal to each other. Wherein the detection element is disposed on one of the ends while being mounted on a flexible substrate, and the spacer is the flexible substrate on which the one end and the detection element are mounted. And a distance from the center of the detection element along the thickness direction of the flexible substrate to the end of the one of the detection elements mounted in the state where the detection element is mounted, The thickness is defined such that the detection element is located at a position where the distance from the center to the one of the ends facing the one end is equal to each other .

Further, the sensor according to claim 2 is the sensor according to claim 1, wherein the core includes a pair of core members, and in a state of surrounding the conductor, each end of one of the core members and the core. a plurality of the respective ends of the other member is configured so as to face each other in a state where the gap occurs respectively, are respectively arranged the one on the one end of each pair of the end portions of the two pairs facing each other wherein a detection element, the one end portion and the same number of each arranged in the respective detecting elements to position respectively the respective detection elements in the central portion of each gap between each sensing element And the spacer.

A current measuring device according to a third aspect includes the sensor according to the first or second aspect, and a measuring unit that measures a current flowing through the conductor based on the detected amount detected by the sensor. ..

According to the sensor of claim 1 and the current measuring device of claim 3, the ends formed of a non-magnetic material and arranged between one of the facing ends and the detection element face each other. By providing a spacer for locating the detection element in the center of the void so that the distances to the parts are equal to each other, it is possible to prevent the situation where the sensitivity varies depending on the position of the conductor in the width direction of the void in the core, The lateral sensitivity of the sensor can be kept constant (or almost constant). Therefore, according to this sensor and the current measuring device, it is possible to sufficiently improve the detection accuracy of the detected amount using the sensor.

Further, according to the sensor of the second aspect and the current measuring device of the third aspect, the pair of core members are arranged at either one of the opposite ends of each pair of the two opposite ends. By providing a plurality of detecting elements and the same number of spacers as the number of detecting elements to be arranged in the center of each void, the direction orthogonal to the width direction of the void in the core (orthogonal direction) It is possible to prevent the sensitivity from varying depending on the position of the conductor and to maintain the sensitivity in the orthogonal direction constant (or almost constant). Therefore, according to this sensor and the current measuring device, the detection accuracy of the detected amount using the sensor can be further improved.

It is a front view of the current measuring device 1. It is a block diagram which shows the structure of the current measuring device 1. It is an explanatory view explaining the composition of sensor 2. It is explanatory drawing explaining the usage method of the electric current measuring apparatus 1. It is explanatory drawing explaining operation|movement of the conventional sensor. It is explanatory drawing explaining operation|movement of the sensor 2. 3 is an explanatory diagram illustrating a configuration of the sensor 102. FIG. 3 is an explanatory diagram illustrating a configuration of a sensor 202. FIG.

Hereinafter, embodiments of the sensor and the current measuring device will be described with reference to the accompanying drawings.

First, the configuration of the current measuring device 1 will be described. The current measuring device 1 shown in FIGS. 1 and 2 is an example of a current measuring device, and measures a current value Im of a current (DC current) Id flowing through a conductor (for example, a lead wire 100 shown in both figures) without contacting a metal. It is configured to be possible. Specifically, the current measuring device 1 is configured to include a sensor 2 and a main body 3 as shown in FIGS.

As shown in FIG. 1, the sensor 2 includes clamp portions 11a and 11b (hereinafter, also referred to as “clamp portion 11” when no distinction is made), and serves as a detected amount that occurs when a current Id flows through the conductor 100. The magnetic field can be detected without contacting the metal.

Further, as shown in FIG. 1, the clamp portion 11a is configured to include a core member 21a, magnetic detection elements 22a and 22b (hereinafter, also referred to as “magnetic detection element 22” when no distinction is made), and a core case 23a. There is. The clamp portion 11b is configured to include a core member 21b (hereinafter, also referred to as "core member 21" when the core members 21a and 21b are not distinguished) and a core case 23b.

In this sensor 2, as shown in FIGS. 1 and 4, the clamp portion 11b is configured to be rotatable around a fulcrum P as a rotation center, and is fixed to the main body case 30 of the main body portion 3 in a state where the clamp portion 11a does not rotate. Has been done. Further, in this sensor 2, the clamp portion 11b is configured to rotate in response to an operation on the lever 30a arranged in the main body case 30 (see FIG. 4).

Further, in this sensor 2, when used, as shown in FIG. 1, the tip portions 11at and 11bt of the clamp portions 11a and 11b and the base end portions 11ae and 11be contact each other, and the clamp portions 11a and 11b contact each other. An annular body is formed.

As shown in FIGS. 1 and 3, the core members 21a and 21b are each formed of a magnetic material in an arc shape in plan view and housed in the core cases 23a and 23b, respectively. In this case, the core members 21a and 21b are formed to have the same length (same shape) as an example, but the core members 21a and 21b may be formed to have different lengths.

Further, as shown in FIG. 1, the core members 21a and 21b have an annular shape that surrounds the conductive wire 100 when an annular body is formed around the conductive wire 100 by the clamp portions 11a and 11b (when the conductive wire 100 is clamped). Make up the core. Further, in the sensor 2, as shown in FIG. 3, when the core members 21a and 21b form an annular core, a gap Ca is formed between the tip end portion 21at of the core member 21a and the tip end portion 21bt of the core member 21b. In the state in which the front end portions 21at and 21bt face each other in the state of occurrence of the gap Cb, a gap Cb (hereinafter, when the gaps Ca and Cb are not distinguished, between the base end portion 21ae of the core member 21a and the base end portion 21be of the core member 21b). The base end portions 21ae and 21be face each other in a state in which a void C) is generated.

The magnetic detection elements 22a and 22b are an example of detection elements, and as shown in FIG. 3, the magnetic detection elements 22a and 22b are arranged (mounted) on the flexible substrate 50 respectively on the front end 21at and the base end 21ae of the core member 21a. It is arranged. In this case, the flexible substrate 50 is arranged along the inner peripheral surface of the core member 21a as shown in the figure, and one end portion (lower end portion in the figure) is connected to the processing section 33 described later. There is.

Further, as shown in FIG. 3, a spacer 24a is arranged between the tip end portion 21at of the core member 21a and the magnetic detection element 22a (the flexible substrate 50 on which the magnetic detection element 22a is mounted). In this case, the spacer 24a is made of a non-magnetic material (for example, resin, copper, aluminum, etc.). Further, as shown in the figure, the thickness of the spacer 24a is regulated to the thickness at which the magnetic detection element 22a is located at a position where the distances to the tip ends 21at, 21bt of the core members 21a, 21b are equal to each other. Therefore, in the magnetic detection element 22a, the spacers 24a are arranged between the tip end portion 21at and the magnetic detection element 22a, so that the distances to the tip end portions 21at and 21bt of the core members 21a and 21b are equal to each other. It is set up. Specifically, as shown in the figure, the magnetic detection element 22a has a distance from the center Ma in the thickness direction of the magnetic detection element 22a (the left-right direction in the figure) to the end face of the tip portion 21at, and the center Ma to the tip. The distance to the end face of the portion 21bt is equal to each other. That is, the magnetic detection element 22a is arranged at the tip portion 21at so as to be located at the center portion in the width direction (left-right direction in the figure) of the void Ca. It is also possible to adopt a configuration in which the magnetic detection element 22a is arranged at the tip portion 21bt of the core member 21b via the spacer 24a.

Further, as shown in FIG. 3, a spacer 24b (hereinafter, spacers 24a, 24b) is also provided between the base end portion 21ae of the core member 21a and the magnetic detection element 22b (the flexible substrate 50 on which the magnetic detection element 22b is mounted). Are also referred to as “spacers 24” when not distinguished. In this case, the thickness of the spacer 24b is defined similarly to the thickness of the spacer 24a. Therefore, in the magnetic detection element 22b, the spacers 24b are arranged between the base end portion 21ae and the magnetic detection element 22b, so that the distances to the base end portions 21ae and 21be of the core members 21a and 21b are equal to each other. It is installed in. Specifically, as shown in the figure, the magnetic detection element 22b has a distance from the center Mb in the thickness direction of the magnetic detection element 22b (the left-right direction in the figure) to the end face of the base end portion 21ae, and the center Mb. The distances to the end surface of the base end portion 21be are equal to each other. That is, the magnetic detection element 22b is arranged at the base end portion 21ae so as to be located at the center portion in the width direction (left-right direction in the drawing) of the void Cb. The magnetic detection element 22b may be arranged on the base end portion 21be of the core member 21b via the spacer 24b.

Each magnetic detection element 22 is, for example, a Hall element and detects a magnetic field as an amount to be detected generated in the core member 21 when a current flows through the conductive wire 100 and outputs a detection signal. Note that the magnetic detection element 22 may be configured by a flux gate type element instead of the Hall element.

As shown in FIGS. 1 and 2, the main body unit 3 is configured to include a display unit 31, an operation unit 32, a processing unit 33, and a main body case 30 in which each of these components is housed or arranged.

The display unit 31 is composed of, for example, a liquid crystal panel, and is disposed on the front panel of the main body case 30 as shown in FIG. The display unit 31 also displays the current value Im of the current Id under the control of the processing unit 33. The operation unit 32 includes various switches 32a and dials 32b arranged on the front panel of the main body case 30, and outputs operation signals corresponding to these operations.

The processing unit 33 controls each unit constituting the main body unit 3 according to the operation signal output from the operation unit 32. In addition, the processing unit 33 functions as a measuring unit, measures the current value Im of the current Id flowing through the conducting wire 100 based on the detection signal output from each magnetic detection element 22 of the sensor 2, and displays it on the display unit 31. ..

Next, how to use the current measuring device 1 will be described with reference to the drawings.

For example, when measuring the current value Im of the current Id flowing through the conducting wire 100 shown in FIG. 4, the switch 32a for power supply in the operation unit 32 of the main body 3 is operated to turn on the power, and then the sensor The conductor wire 100 is clamped by each clamp portion 11 of No. 2. Specifically, the lever 30a arranged in the body case 30 of the body portion 3 is pushed. At this time, as shown in the figure, the clamp portion 11b rotates about the fulcrum P as a rotation center so that the tip portion 11bt of the clamp portion 11b separates from the tip portion 11at of the clamp portion 11a and the clamp portion 11b. The base end portion 11be of the above is separated from the base end portion 11ae of the clamp portion 11a.

Subsequently, the conductor wire 100 is passed through the gap between the tip portions 11at and 11bt of the clamp portions 11a and 11b, and then the pushing of the lever 30a is released, whereby the clamp portions 11a and 11b are released as shown in FIG. The front end portions 11at and 11bt of the above and the base end portions 11ae and 11be of the clamp portions 11a and 11b are brought into contact with each other. As a result, the clamp portions 11a and 11b form an annular body around the conductor 100, and the core members 21a and 21b form an annular core that surrounds the conductor 100 to clamp the conductor 100.

Further, in this state, as shown in FIG. 3, the tip portions 21at and 21bt face each other with a gap Ca formed between the tip portion 21at of the core member 21a and the tip portion 21bt of the core member 21b. The base ends 21ae and 21be are opposed to each other in a state in which a gap Cb is formed between the base end 21ae of the member 21a and the base end 21be of the core member 21b.

In this case, when the current Id is flowing through the conductor 100, the magnetic detection elements 22a and 22b detect the magnetic field generated in the core members 21a and 21b by the current Id, and output a detection signal. In addition, the processing unit 33 measures the current value Im of the current Id flowing through the conductor 100 based on the detection signals output from the magnetic detection elements 22a and 22b, and causes the display unit 31 to display the measured current value Im.

Here, for example, as shown in FIG. 5, the magnetic detection element 22 is disposed so as to contact one of the opposed ends of the core member 21, and in the space C between the opposed ends of the magnetic detection element 22. In the conventional sensor that is not located in the center portion in the width direction (located on the right side in the figure), the conductor 100 has a center portion in the left-right direction (direction parallel to the width direction of the void C) in the annular core. When the core member 21 is not located at the position (in the example of the figure, it is located on the right side of the central portion), the core member 21 passes through both of the opposing end portions (the tip portions 21at and 21bt in the figure). In addition to the magnetic flux line (for example, the magnetic flux line L1 shown in the same figure), the magnetic flux line L2 that passes through only one of the opposing end portions (the tip portion 21at in the same figure) is also detected. In this case, the magnetic flux line L2 is not detected by the magnetic detection element 22 when the conducting wire 100 is located in the center portion in the left-right direction within the annular core. Therefore, in the conventional sensor in which the magnetic detection element 22 is not located at the center of the air gap C, the sensitivity varies depending on the position of the conductor 100 in the left-right direction within the annular core.

On the other hand, in this sensor 2, the magnetic detection element 22 is arranged so as to be located at the center portion in the width direction of the space C between the end portions of the core member 21 which face each other, and therefore, in FIG. As shown, the magnetic flux line L2 generated when the conductor wire 100 is not located in the center portion in the left-right direction in the annular core is not detected by the magnetic detection element 22, so that the conductor wire 100 in the left-right direction in the annular core is not detected. The same (or nearly the same) sensitivity as when located in the center is maintained. In other words, in this sensor 2, it is possible to prevent the situation where the sensitivity varies depending on the position of the conductor 100 in the left-right direction within the annular core, and maintain the sensitivity in the left-right direction constant (or almost constant). Has become.

In addition, the sensor 2 includes a pair of core members 21a and 21b, and the voids Ca and Cb generated between the distal end portions 21at and 21bt facing each other and the proximal end portions 21ae and 21be of the core members 21a and 21b, respectively. The magnetic detection elements 22a and 22b are arranged one by one so as to be located at the center portion in the width direction. Therefore, in this sensor 2, by adjusting the values of the magnetic fields detected by the magnetic detection elements 22a and 22b, the conductor 100 in the vertical direction (direction orthogonal to the width direction of the voids Ca and Cb) in the annular core. It is possible to prevent the sensitivity from changing depending on the position of, and maintain the sensitivity in the vertical direction constant (or almost constant).

Then, when the measurement is completed, the lever 30a is pushed in to rotate the clamp portion 11b, and the tip portion 11bt and the base end portion 11be of the clamp portion 11b are respectively moved from the tip portion 11at and the base end portion 11ae of the clamp portion 11a. The wires 100 are separated from each other (see FIG. 4), and the conducting wire 100 is positioned outside the sensor 2 through the gap between the tip portions 11at and 11bt. Then, the pushing of the lever 30a is released.

As described above, according to the sensor 2 and the current measuring device 1, each of the core members 21 facing each other, which is made of a nonmagnetic material and is arranged between the end of the core member 21 and the magnetic detection element 22, is provided. By providing the spacer 24 for locating the magnetic detection element 22 at the center in the width direction of the air gap C so that the distances to the ends are equal to each other, the left and right directions in the annular core formed by the core members 21 It is possible to prevent a situation in which the sensitivity varies depending on the position of the conductive wire 100 (in the width direction of the air gap C), and to maintain the lateral sensitivity of the sensor 2 constant (or almost constant). Therefore, according to the sensor 2 and the current measuring device 1, the detection accuracy of the magnetic field (detection amount) using the sensor 2 can be sufficiently improved.

Further, according to the sensor 2 and the current measuring device 1, one of the front end portions 21at and 21bt (the front end portion 21at) of the pair of core members 21a and 21b facing each other and one of the base end portions 21ae and 21be facing each other. Two magnetic detection elements 22a and 22b respectively arranged on the (base end portion 21ae) and two magnetic detection elements 22a and 22b (the same number as the number of detection elements) arranged at the central portions of the voids Ca and Cb, respectively. Since the spacers 24a and 24b are provided, the sensitivity is increased according to the position of the conductive wire 100 in the vertical direction (direction orthogonal to the width direction of the voids Ca and Cb) in the annular core formed by the core members 21a and 21b. It is possible to prevent different situations and maintain the sensitivity in the vertical direction constant (or almost constant). Therefore, according to the sensor 2 and the current measuring device 1, the detection accuracy of the magnetic field (detection amount) using the sensor 2 can be further improved.

The configurations of the sensor and the current measuring device are not limited to the above configurations. For example, the configuration example including the two core members 21a and 21b and the two magnetic detection elements 22a and 22b has been described above, but the numbers of the core members 21 and the magnetic detection elements 22 are not limited to this, and an arbitrary number. A configuration including the core member 21 and the magnetic detection element 22 can be adopted.

As an example, as shown in FIG. 7, four core members 21c to 21f that form an annular core when surrounding the conductor 100 (conductor to be detected) and four magnetic detection elements 22c to 22f are provided. The sensor 102 can be employed. In this case, the core members 21c to 21f are formed to have the same length (same shape) as an example, but the core members 21c to 21f may be formed to have different lengths. In this sensor 102, spacers 24c to 24f made of a non-magnetic material are arranged between the end portions of the core members 21c to 21f and the magnetic detection elements 22c to 22f, respectively, and thereby the core members 21c to 21f. The magnetic detection elements 22c to 22f are arranged so as to be located at the center portions in the width direction of the air gaps Cc to Cf between the opposing ends of the. Therefore, also in this sensor 102, the sensitivity in the left-right direction and the up-down direction in the annular core formed by the core members 21c to 21f can be maintained constant (or almost constant). It is possible to sufficiently improve the detection accuracy of the existing magnetic field (detection amount).

Further, as shown in FIG. 8, a sensor 202 including one core member 21g that functions as an annular core that can surround the conductor 100 (conductor to be detected) and one magnetic detection element 22g is used. Can also In this sensor 202, a spacer 24g formed of a non-magnetic material is arranged between the end of the core member 21g and the magnetic detection element 22g, whereby the width of the gap Cg between the opposite ends of the core member 21g. The magnetic detection element 22g is arranged so as to be located at the central portion in the direction. Therefore, also in this sensor 202, the sensitivity in the left-right direction in the core member 21g can be maintained constant (or almost constant), and therefore the detection accuracy of the magnetic field (detection amount) using the sensor 202 is sufficiently high. Can be improved.

1 current measuring device 2 sensor 21a-21g core member 21ae, 21be base end part 21at, 21bt tip part 22a-22g magnetic detection element 24a-24g spacer 33 processing part 100 conducting wire 102 sensor 202 sensor Ca-Cg void

Claims (3)

Arranged on either one of the cores configured so that the respective end portions face each other in a state in which a gap is formed between the respective end portions in a state of surrounding the conductor to be detected, and the respective end portions that face each other. A sensor provided with a detection element for detecting an amount to be detected generated in the core when an electric current flows through the conductor,
The detection element is made of a non-magnetic material and is disposed between any one of the end portions and the detection element, and the detection element is arranged so that the distances to the opposite end portions are equal to each other. comprising a spacer is positioned,
The detection element is arranged at one of the ends while being mounted on a flexible substrate,
The spacer is arranged along the thickness direction of the flexible board at the portion where the detection element is mounted in a state where the spacer is arranged between the one end and the flexible board where the detection element is mounted. The distance from the center of the detection element to the one of the ends and the distance from the center of the detection element to the end opposite to the one of the ends is equal to each other. The sensor specified by the thickness to be located . The core includes a pair of core members, and in a state of surrounding the conductor, each end of one of the core members and each end of the other of the core members face each other in a state in which a gap is generated. Is configured as
A plurality of the detection elements respectively arranged at any one of the ends of each pair of the two ends facing each other;
And a said spacer as many of the respective detecting elements which are disposed respectively the respective detection elements are positioned respectively above the center of each gap between the one and the one end portion and the respective detecting elements The sensor according to claim 1, wherein A current measuring device comprising: the sensor according to claim 1; and a measuring unit that measures a current flowing through the conductor based on the detected amount detected by the sensor.

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