JP2003139802A - Current sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current sensor capable of detecting a current with high accuracy. SOLUTION: In the current sensor 1, a sensor main body 3 comprises both a core material 6 and a winding 7 formed in the outer circumferential surface of the core material 6, and the sensor main body 3 is circularly connectable. The current sensor 1 is constituted so as to detect a current passing through an object to be measured by the winding 7 with an conductor to be measured surrounded. The current sensor 1 is provided with a first bobbin 9 and a second bobbin 10. The first bobbin 9 is mounted coaxially with the axis of the core material 6 to the end part of the core material 6 on the side of one end of a circularly connected connecting part, and a column-shaped first spool part 9a of an outer diameter formed smaller than the outer diameter of the core material 6 is formed on the side of the tip end part of the first bobbin 9. The second bobbin 10 is mounted coaxially with the axis of the core material 6 to the end part of the core material 6 on the side of the other end of the connecting part, and a cylindrical second spool part 10a of an outer diameter formed larger than the outer diameter of the core diameter 6 is formed on the side of the tip part of the second bobbin 10. The winding 7 on the side of one end of the connecting part is wound by the first spool part 9a, and the winding 7 on the side of the other end of the connecting part is wound by the second spool part 10a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current sensor which is installed so as to surround an outer circumference of a conductor to be measured and which detects a current flowing through the conductor to be measured.

[0002]

2. Description of the Related Art As this type of current sensor, a current sensor 51 shown in FIGS. 7 and 8 has been conventionally known. As shown in FIG. 7, the current sensor 51 is installed so as to surround the connection cable 2 for connecting to a measuring device (not shown) and the outer circumference of the conductor X to be measured, and detects the current flowing through the conductor X to be measured. Cable-shaped sensor main body 53 for performing the operation, and a first cover member 54 attached to one end of the sensor main body 53.
And a second cover member 55 attached to the other end of the sensor body 53.

As shown in FIG. 8, the sensor main body 53 is provided with a core material 6, a winding wire 7 and an outer jacket 8, and is used as a Rogowski coil. In this case, the core material 6 is made of a flexible resin material and formed into a long cylindrical shape having a uniform outer diameter. The winding wire 7 is formed of a covered electric wire, and is wound around the outer peripheral surface of the core material 6 uniformly (one layer as one example) over substantially the entire length of the core material 6. Also, the core material 6
At both ends, as shown in FIG. 8, the windings are wound in multiple layers so that the winding density is higher than that of other portions. Therefore, when the sensor main body 5 is installed so as to surround the conductor X to be measured, the sensor main body 5 is caused by the manufacturing accuracy of the winding wire 7 and the plate thickness of each cover member 54, 55.
The output decrease in the gap Y portion of the winding wire 7 that occurs between both ends of the winding wire 3 is corrected. Further, the winding wire 7 is folded back at one end of the core material 6 and drawn from the other end of the core material 6 through the center of the core material 6 (so-called return route, not shown),
It is electrically connected to the connection cable 2 together with the winding start end. The outer cover 8 is formed on the outer periphery of the core material 6 so as to cover the winding 7, and prevents the winding 7 from being unwound.

The first cover member 54 is made of a resin material and has a cylindrical shape which is closed at one end and is closed at the other end by a wall portion 54a having a substantially uniform plate thickness. In this case, the inner diameter of the first cover member 54 is set to be equal to the outer diameter of the sensor body 53. The first cover member 54 is attached to one end of the sensor main body 53 by being inserted from one end side that opens until one end of the sensor main body 53 contacts the inner surface of the wall portion 54a. Second
The cover member 55 is formed of a resin material in a cylindrical shape, and a partition wall 55a having a substantially uniform plate thickness is disposed inside the cover member 55 so as to be orthogonal to the axis.
Therefore, the partition wall 55a divides the internal space of the second cover member 55 into two regions A and B. In this case, the inner diameter of the area A in the second cover member 55 is formed to be equal to the outer diameter of the sensor body 53, and the inner diameter of the area B in the second cover member 55 is slightly smaller than the outer diameter of the first cover member 54. It has a large diameter. This allows the second
The cover member 55 is attached to the other end of the sensor main body 53 by being inserted into the area A from the one end side that opens until the other end of the sensor main body 53 comes into contact with the inner surface of the partition wall 55a. Further, in the first cover member 54 and the second cover member 55, the tip end of the first cover member 54 is within the region B from the other end side where the first cover member 54 opens the second cover member 55 and the partition wall 55a is formed. It is inserted until it abuts the inner surface, and is separably connected to each other by a lock mechanism (not shown).

When measuring the current flowing through the conductor X to be measured using this current sensor 51, the first cover member 54 is used.
And the second cover member 55 are separated, the sensor main body 53 is wound around the outer circumference of the conductor X to be measured, and the first cover member 54 and the second cover member 55 are connected to each other as shown in FIG. To form the current sensor 51 in an annular shape. This completes the installation of the current sensor 51. In this state,
As shown in FIG. 8, the respective ends of the winding wire 7 are maintained in a state where their respective axes coincide with each other and face each other. On the other hand, when a current flows in the conductor X to be measured, the magnetic field generated around the conductor X to be measured changes in accordance with the current value, so that the magnetic field penetrating the winding 7 also changes. , A voltage resulting from the change in the magnetic field is induced across the winding 7. In this case, the measuring device (not shown) is the connection cable 2
This induced voltage input via is measured. Thereby, the current flowing through the conductor X to be measured is measured.

[0006]

However, the conventional current sensor 51 has the following problems. That is, in the conventional current sensor 51, when the first cover member 54 and the second cover member 55 are connected, both ends of the winding 7, the wall portion 54 a of the first cover member 54, and the second cover member 55.
The partition walls 55a are arranged in a straight line along the axis of the core material 6. Therefore, a gap Y between the end faces of the winding wire 7 is equal to or more than the total thickness of the wall portions 54a of the first cover member 54 and the partition walls 55a of the second cover member 55.
Occurs. In this case, in the current sensor 51, as described above, the winding density of the winding 7 at both end portions of the core material 6 is made higher than that of other portions, so that the decrease in the coil output due to the gap Y is corrected. Has been adopted. However, since there is a relatively wide gap Y, the position and inclination of the measurement target conductor X change inside the current sensor 51 formed in an annular shape (effective measurement range), so that the current flows to the measurement target conductor X. Phenomenon in which when the magnetic field based on the current makes a certain angle and interlinks with the air gap Y, the induced voltage of the winding 7 changes and an error occurs even if the current flowing through the conductor X to be measured is constant. Occurs. Therefore, in such a case, it is difficult to detect the current flowing through the conductor X to be measured with high accuracy.

The present invention has been made in view of the above problems, and its main object is to provide a current sensor capable of detecting a current with high accuracy.

[0008]

To achieve the above object, a current sensor according to a first aspect of the present invention comprises one or a plurality of sensor bodies each having a core member and a winding wire formed on an outer peripheral surface of the core member. A current sensor which is formed so as to be connectable in an annular shape and which is capable of detecting a current flowing through the measurement object with the winding in a state of surrounding the measurement object conductor, wherein one end side of the connection part connected in the annular shape At the end of the core member, a cylindrical first winding frame part is attached coaxially with the axis of the core member, and the outer diameter of which is smaller than the outer diameter of the core member on the tip side. The formed first bobbin and the end portion of the core member on the other end side of the connecting portion are attached coaxially with the axis of the core member, and the outer diameter thereof is larger than the outer diameter of the core member. A second bobbin having a cylindrical second winding frame portion formed on the tip end side. The winding on the one end side of the connection part is wound around the first winding frame part, and the winding on the other end side of the connection part is wound around the second winding frame part. There is.

According to a second aspect of the present invention, in the current sensor of the first aspect, the first bobbin and the second bobbin have a cylindrical cap portion into which the end portion of the core member can be inserted. It is formed on the end face side facing the core material.

According to a third aspect of the present invention, in the current sensor according to the first or second aspect, the one end of the connecting portion can be inserted from the opened one end side, and
The other end side is closed by a wall portion, and a cylindrical projection into which the first winding frame portion can be inserted is formed in a cylindrical shape with a cylindrical first cover member protruding outwardly from the wall portion. And a partition wall is formed therein, and the other end of the connecting portion is configured to be insertable from one end side thereof, and the first cover member is configured to be insertable from the other end side thereof,
And a second cover member in which a circular recess into which the cylindrical protrusion of the inserted first cover member can be fitted is formed in a central portion of the partition wall, and the second cover member comprises:
The second bobbin frame portion of the second bobbin can be fitted between the inner peripheral surface and the outer peripheral surface of the circular recess.

A current sensor according to a fourth aspect is the current sensor according to any one of the first to third aspects, wherein the first sensor
An end portion of the winding wound around the first winding frame portion of the bobbin and an end portion of the winding winding around the second winding frame portion of the second coil bobbin are connected in an annular shape. In this state, they are arranged on the same plane.

A current sensor according to a fifth aspect is the current sensor according to any one of the first to fourth aspects, wherein
The winding frame portion and the second winding frame portion are each formed such that the average value of the cross-sectional areas of the both is equal to the cross-sectional area of the core material.

According to a sixth aspect of the present invention, there is provided the current sensor according to any of the first to fifth aspects, which is configured as a Rogowski coil.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a current sensor 1 according to the present invention will be described below with reference to the accompanying drawings. The same components as those of the conventional current sensor 51 are designated by the same reference numerals, and duplicate description will be omitted.

First, the configuration of the current sensor 1 will be described with reference to the drawings.

As shown in FIG. 7, the current sensor 1 is installed so as to surround the connection cable 2 for connecting to a measuring device (not shown) and the outer circumference of the conductor X to be measured. Cable-like sensor main body 3 for detecting (a single piece as an example), a first cover member 4 attached to one end of the sensor main body 3, and a second cover attached to the other end of the sensor main body 3. And a member 5.

As shown in FIGS. 1 to 3, the sensor body 3 is provided with a core material 6, a winding wire 7, a jacket 8, a first bobbin 9 and a second bobbin 10, and can be used as a Rogowski coil. It is configured. In this case, the core material 6 is formed in a columnar shape (cable shape) with a uniform outer diameter C using a flexible resin material (silicone resin as an example).

As shown in FIG. 4, the first bobbin 9 is made of, for example, a resin material, and has a first winding frame portion 9a and a first cap portion 9b. in this case,
The outer diameter D of the first winding frame portion 9a is smaller than the outer diameter C of the core material 6 and is formed in a cylindrical shape having a length E. Also,
The first winding frame portion 9a is formed such that one flange portion 9c and the other flange portion 9d have a large diameter. The first cap portion 9b is formed in a cylindrical shape, and is disposed coaxially with the first winding frame portion 9a on the side surface (end surface facing the core material 6) of the flange portion 9d. The first cap portion 9b has a length G
The outer diameter F is slightly larger than the outer diameter of the core material 6, and the inner diameter is formed to be equal to the outer diameter of the core material 6.
Further, a through hole 9e is formed in the central portion of the first bobbin 9 so that a return route described later can be wired (see FIG. 1).
With this configuration, the first bobbin 9 is, as shown in FIG.
The core material 6 is attached to one end side of the core material 6 while the one end side of the core material 6 is inserted into the first cap portion 9b.

On the other hand, the second bobbin 10 is made of, for example, a resin material as shown in FIG.
a and the second cap portion 10b. In this case, the outer diameter H of the second winding frame portion 10a is larger than the outer diameter C of the core material 6 and is formed in a cylindrical shape having a length I. Further, the second winding frame portion 10a has flange portions 10c and 10d formed at both ends of the outer peripheral surface thereof, and the end surface side where the flange portion 10d is formed is closed. The second cap portion 10b is formed in the same shape as the first cap portion 9b of the first bobbin 9 (a cylindrical body having a length G, an outer diameter F, and an inner diameter equal to the outer diameter of the core material 6). Second
The closed end surface (end surface facing the core material 6) of the winding frame portion 10a on the flange portion 10d side is disposed coaxially with the second winding frame portion 10a. With this configuration, the second bobbin 10
Is attached to the other end side of the core material 6 with the other end side of the core material 6 inserted in the second cap portion 10b.

The winding 7 is a covered electric wire (enamel copper wire)
Starting to wind from the second bobbin portion 10a of the second bobbin 10, then the outer circumference of the second cap portion 10b, the outer circumference of the core material 6, and the first
It is sequentially wound around the outer circumference of the cap portion 9b and the outer circumference of the first winding frame portion 9a. Further, the covered electric wire is folded back at one end of the core material 6 (on the side of the first bobbin 9) and drawn out from the other end of the core material 6 (on the side of the second bobbin 10) through the center of the core material 6 (so-called). Return route), and is electrically connected to the connection cable 2 together with the winding start end. In this case, when wiring the covered electric wire from the second winding frame portion 10a to the second cap portion 10b, when wiring from the second cap portion 10b to the core material 6,
When wiring from the core material 6 to the first cap portion 9b, when wiring from the first cap portion 9b to the first winding frame portion 9a, and when wiring from the first winding frame portion 9a to the through hole 9e, The notches formed in the respective flange portions of the first bobbin 9 and the second bobbin 10 are used. The outer cover 8 is closely formed on the outer periphery of the core material 6 so as to cover the entire winding wire 7 wound around the core material 6, and prevents the winding wire 7 from being unwound.

Further, in the current sensor 1, the first cover member 4 and the second cover member 5 are connected to each other when the current sensor 1 is installed so as to surround the outer circumference of the conductor X to be measured.
The winding 7 wound around the bobbin 9 and the second bobbin 10 has
They are placed close to each other. On the other hand, in order to improve the measurement accuracy, when the current flowing through the conductor X to be measured is constant, the position and inclination of the conductor X to be measured inside the current sensor 1 formed in an annular shape (effective measurement range) change. Even if it does, it is preferable that the measured current value does not change. For this purpose, the coil output per unit length of the winding (coil) 7 wound around the first bobbin 9 and the second bobbin 10 (the voltage detected by the winding 7, that is, the current flowing through the winding 7 is The average value of the converted voltage) is equal to the coil output per unit length in the winding 7 wound around the core material 6, and the coil output per unit length in the current sensor 1 is uniform over the entire circumference. Is preferred. In this case, the coil output v,
Between the cross-sectional area S of the winding and the number N of windings, the following (1)
The formula holds. v = −μo × S × N / L (1) where L means the average magnetic path length and μo means the magnetic permeability of vacuum.

On the other hand, in the current sensor 1, the winding 7 is
Since the core material 6, the first bobbin 9, and the second bobbin 10 are wound uniformly in one layer along the outer peripheral surface, the number of windings per unit length (unit magnetic path length) is a constant value. (N / L is constant). Therefore, in this current sensor 1, the coil output v is proportional to the cross-sectional area S of the winding 7. Further, in the current sensor 1, the average value of the cross-sectional area of the winding wire 7 wound around the first winding frame portion 9a and the cross-sectional area of the winding wire 7 around the second winding frame portion 10a is the core value. The cross-sectional area of the winding wire 7 wound around the material 6 is set as close as possible. Specifically, the cross-sectional areas of the windings 7 wound around the winding frame portions 9a and 10a are substantially equal to the cross-sectional areas of the outer peripheral surfaces of the winding frame portions 9a and 10a, and the winding material 7 is wound around the core material 6. The cross-sectional area of the winding wire 7 is substantially equal to the cross-sectional area of the core material 6. For this reason, each reel 9a, 10a
So that the average value of each cross-sectional area of the outer peripheral surface of the core material 6 is equal to the cross-sectional area of the core material 6, that is, the average from the left end portion of the first winding frame portion 9a to the right end portion of the second winding frame portion 10a in FIG. The winding frame 9a, so that the cross-sectional area is substantially equal to the cross-sectional area of the core material 6,
The outer diameters D and H of 10a are specified. Therefore,
This current sensor 1 has a coil output v per unit length including the first bobbin 9 and the second bobbin 10.
Is configured to be uniform over the entire circumference. In the current sensor 1, the cross-sectional area of the winding 7 wound around the caps 9b and 10b of the first bobbin 9 and the second bobbin 10 is the cross-sectional area of the winding 7 wound around the core 6. Since the difference between the coil outputs v based on the difference between the cross-sectional areas is neglected, the cap portions 9b,
The core material 6 and the average cross-sectional area of the winding wire 7 wound around the first bobbin 9 and the second bobbin 10 including the cross-sectional area of the winding wire 7 of 10b.
The outer diameters D and H of the winding frame portions 9a and 10a may be specified so that the cross-sectional area of the winding wire 7 wound on the coil is the same.

The first cover member 4, as shown in FIG.
A resin material is used to form a cylindrical shape with one end open and the other end closed. In addition, the first cover member 4
Is configured so that one end of the sensor body 3 to which the first bobbin 9 is attached can be inserted from one end side that opens. Further, the first bobbin 9 is provided coaxially with the first cover member 4 at the central portion of the wall portion 4a that closes the other end side of the first cover member 4.
A cylindrical projection 4b into which the entire first winding frame portion 9a can be inserted is provided so as to project outward. In this case, the first bobbin 9
As shown in FIG. 3, together with one end of the sensor body 3, the first
When inserted into the cover member 4, the flange portion 9d comes into contact with the inner surface of the wall portion 4a, and the entire first winding frame portion 9a is inserted into the cylindrical protrusion 4b.

The second cover member 5, as shown in FIG.
The resin material is formed into a cylindrical shape, and the partition wall 5a is arranged therein. Therefore, the internal space of the second cover member 5 is divided into two regions A and B by the partition wall 5a. In this case, the inner diameter of the area A in the second cover member 5 is set to be slightly larger than the maximum outer diameter of the sensor body 3, and the inner diameter of the area B in the second cover member 5 is outside the first cover member 4. The diameter is set to be slightly larger than the diameter and larger than the inner diameter of the region A. Further, a circular recess 5b is formed in the central portion of the partition wall 5a so as to be coaxial with the second cover member 5 and project toward the area A. Further, the circular recess 5b has an inner diameter set to be slightly larger than the outer diameter of the cylindrical protrusion 4b of the first cover member 4,
Moreover, its depth is set to be equal to the length of the cylindrical protrusion 4b. The outer diameter of the circular recess 5b is formed to be slightly smaller than the inner diameter of the second winding frame portion 10a of the second bobbin 10, and the outer peripheral surface thereof and the area A of the second cover member 5 are formed.
A space into which the second bobbin frame portion 10a of the second bobbin 10 can be fitted is formed between the inner peripheral surface and the inner peripheral surface. Further, the circular concave portion 5b is formed from the partition wall 5a to the second winding frame portion 10a.
Is formed so as to protrude beyond the length I. Therefore,
When the second winding frame portion 10a is mounted in the circular recess 5b,
The tip surface of the circular recess 5b contacts the flange portion 10d of 10b. In addition, the first cover member 4 and the second cover member 5 are not shown for connecting the second cover member 5 and the first cover member 4 inserted into the region B of the second cover member 5 in a separable manner. A lock mechanism is provided.

Next, regarding how to use the current sensor 1,
A description will be given with reference to the drawings.

Using this current sensor 1, the conductor X to be measured
When measuring the current flowing through the sensor body 3, the sensor main body 3 is wound around the conductor X to be measured in a state where the first cover member 4 and the second cover member 5 are separated, and then the first cover member 4 is moved to the second cover member 4. By inserting the cover member 5 into the region B, as shown in FIG. 7, the first cover member 4 and the second cover member 5 are inserted.
And are connected to form the current sensor 1 in an annular shape. This completes the installation of the current sensor 1. In this state, as shown in FIG. 3, the cylindrical protrusion 4b of the first cover member 4 enters the circular recess 5b of the second cover member 5, and the cylindrical protrusion 4b and the circular recess 5b have a so-called nested structure. Become.
For this reason, the tip end of the first bobbin frame portion 9a of the first bobbin 9 fitted in the cylindrical protrusion 4b has the second cover member 5 attached thereto.
Area A of the second cover member 5 beyond the partition wall 5a in
Placed on the side. As a result, as shown in the figure, the tip of the winding wire 7 wound around the first winding frame portion 9a and the second winding frame portion 10a.
The tip portion of the winding wire 7 wound around a is the first cover member 4
Despite the presence of the wall portion 4a and the partition wall 5a of the second cover member 5, they are connected via a gap Z that is sufficiently narrower (for example, zero) than the plate thickness of the wall portion 4a and the partition wall 5a.
That is, in the current sensor 1, the tip portion of the winding wire 7 wound around the first winding frame portion 9a and the winding wire 7 winding around the second winding frame portion 10a.
It is formed in an annular shape without forming a discontinuity point with the tip of the.

When measuring the current, a measuring device (not shown) inputs the voltage induced in the winding 7 of the current sensor 1 through the connection cable 2 and measures the voltage. In this case, in the current sensor 1, as described above, the current sensors 1 are connected in an annular shape without discontinuities. Therefore, according to the current sensor 1, even if the position or inclination of the measurement target conductor X inside the current sensor 1 formed in an annular shape (effective measurement range) changes, an error component is generated in the induced voltage. Therefore, the voltage according to the current value flowing through the conductor X to be measured can be detected with high accuracy and stability.

The present invention is not limited to the above-described embodiments of the invention, and can be modified as appropriate. For example, the above-described current sensor 1 is configured so that both ends of one sensor main body 3 are connected to each other to be formed into an annular shape. However, as shown in FIG. It is also possible to adopt the structure formed in the above. Further, in the embodiment of the present invention, a configuration is adopted in which the respective end portions of the core material 6 formed to have the same diameter over the whole are fitted into the cap portions 9b and 10b and the bobbins 9 and 10 are attached. The outer diameters of the respective cap portions 9b and 10b and the outer diameter of the core material 6 are formed to be the same, and the diameters of the respective end portions of the core material 6 are slightly reduced so that they can be inserted into the respective cap portions 9b and 10b. It is also possible to adopt a configuration of forming. According to this configuration, the cross-sectional areas of the windings wound around the cap portions 9b and 10b,
Since the cross-sectional area of the winding wound around the core material 6 can be set to be the same, the variation of the coil output v can be completely eliminated and the measurement can be performed with higher accuracy.

Further, in the embodiment of the present invention, the cap portions 9b and 10b are respectively arranged on the bobbins 9 and 10 to facilitate the attachment to the core material 6 and to wind the core material 6 around the axis line. Although the structure which can improve the positioning accuracy of the axes of the frame portions 9a and 10a is adopted, the cap portions 9b and 1 are
It is also possible to configure the bobbins 9 and 10 only with the reel portions 9a and 9b without disposing the 0b. In this case, the bobbins 9 and 10 can be directly attached to the core 6 by adhesion or the like. Further, in the embodiment of the present invention, the example in which the current sensor 1 is applied to the Rogowski coil has been described.
The current sensor according to the present invention is not limited to this, and can be applied to various sensing coils. Also,
As an example of the material of the core member 6 forming the sensor main body 3, a flexible and flexible silicone resin is used. However, a rigid material (such as a magnetic core) is used for a clamp sensor. It can also be applied. Furthermore, the first and second cover members in the present invention are not limited to the configuration of both cover members 4 and 5, but the configuration can be appropriately changed by providing the lock mechanism as described above.

[0030]

As described above, according to the current sensor of the present invention, the first bobbin in which the first winding frame portion is formed on the tip end side and the second bobbin portion is formed on the tip end side. A second bobbin is provided, and the winding on one end side in the connection part is wound around the first winding frame part, and the winding on the other end side in the connection part is wound around the second winding frame part. Even when a configuration is adopted in which a pair of cover members respectively covering one end and the first bobbin of the sensor body and the other end of the sensor body and the second bobbin are interposed between both ends of the winding, each cover member is in contact with the other. Since the contacting parts can have a nested structure, the current sensor can be connected in an annular shape without discontinuity,
Even if the position or inclination of the conductor to be measured inside the current sensor connected in a ring (effective measurement range) changes, the voltage corresponding to the current value flowing in the conductor to be measured does not cause an error in the induced voltage. Can be detected with high accuracy and stability. Further, by winding the winding wire around the winding frame portion, unwinding of the winding wire can be avoided even when an external force is applied, so that the durability thereof can be improved.

Further, according to the current sensor of the present invention, the first cylindrical cap portion into which the end portion of the core member can be inserted is formed.
By forming the bobbin and the second bobbin, the mountability of each bobbin to the core material can be enhanced, and the positioning accuracy of the axis line of each bobbin with respect to the axis line of the core material can be enhanced.

Further, according to the current sensor of the present invention, one end of the sensor body to which the first bobbin is attached is covered with the first cover member, and the other end of the sensor body to which the second bobbin is attached is second cover member. By covering the two covers with each other, the portions where the respective cover members abut each other can be formed into a nested structure when the two covers are connected, so that the current sensor can be formed in an annular shape without discontinuity.

Further, according to the current sensor of the present invention, the ends of the windings wound around the first bobbin and the ends of the windings wound around the second coil bobbin are the same when connected in an annular shape. By arranging on the plane, the current sensor can be surely formed in an annular shape without discontinuity, and as a result, the current of the conductor to be measured can be detected with higher accuracy and stability.

Further, according to the current sensor of the present invention, the first winding frame portion and the second winding frame portion are formed so that the average value of each cross-sectional area is equal to the cross-sectional area of the core material. The average value of the coil output per unit length of the winding wound around the first winding frame portion and the coil output per unit length of the winding wound around the second winding frame portion, and the winding wound around the core material The coil output per unit length can be made equal. Therefore, it is possible to reduce the variation in the coil output along the length direction of the sensor body, so even if the position or inclination of the conductor to be measured within the effective measurement range changes, the current value flowing in the conductor to be measured does not change. The corresponding voltage can be detected with high accuracy and stability.

Further, by applying the current sensor of the present invention to the Rogowski coil, it is assumed that the winding can be separated at an intermediate portion when the conductor to be measured is mounted so as to surround the conductor to be measured. Can be sufficiently ensured, and highly accurate and stable current detection can be performed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of one end side of a current sensor 1 according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the other end side of the current sensor 1.

FIG. 3 is a cross-sectional view of a connected portion in which both ends of the current sensor 1 are connected.

FIG. 4 is a perspective view of a first bobbin 9.

FIG. 5 is a perspective view of a second bobbin 10.

FIG. 6 is a plan view showing a state in which a plurality of (two as an example) current sensors 1 are used and connected.

FIG. 7 is a plan view showing a usage state of a current sensor 1 (51).

FIG. 8 is a cross-sectional view of a connected portion in a state where both ends of a conventional current sensor 51 are connected.

[Explanation of symbols]

1 Current sensor 2 connection cable 3 sensor body 4 First cover member 4a wall 4b cylindrical protrusion 5 Second cover member 5a division wall 5b circular recess 6 core material 7 windings 9 First bobbin 9a First reel part 9b First cap part 10 Second bobbin 10a Second winding frame part 10b Second cap part X Conductor to be measured

Claims (6)

[Claims] 1. A measurement target formed in such a manner that one or a plurality of sensor main bodies each having a core member and a winding formed on an outer peripheral surface of the core member can be connected in an annular shape, and surrounds a conductor to be measured. A current sensor configured to detect a current flowing through a body by the winding, wherein the current sensor is attached to an end portion of the core member on one end side of the annularly connected connection portion coaxially with the axis of the core member. A first bobbin having a cylindrical first winding frame portion whose outer diameter is smaller than the outer diameter of the core material and which is formed on the tip end side; and the core material on the other end side of the connecting portion. A cylindrical second winding frame part, which is attached to the end part of the core member coaxially with the axis of the core member and has an outer diameter larger than the outer diameter of the core member, is formed on the tip end side. A second bobbin, wherein the winding on the one end side of the connecting portion is the first winding frame portion A current sensor in which the winding on the other end side of the connection portion is wound around the second winding frame portion. 2. The first bobbin and the second bobbin are configured such that a cylindrical cap portion into which the end portion of the core member can be inserted is formed on an end face side facing the core member. The current sensor according to item 1. 3. A cylindrical projection, which is configured such that the one end of the connecting portion can be inserted from the opened one end side, and the other end side is closed by a wall portion, and into which the first winding frame portion can be inserted is outside. A cylindrical first cover member protruding toward the wall toward the side, and a partition wall formed inside and having a cylindrical shape, and the other end of the connecting portion is inserted from one end side thereof The first cover member is configured to be insertable from the other end side, and the circular recess into which the cylindrical protrusion of the inserted first cover member can be fitted is a center of the partition wall. A second cover member formed in a portion of the second bobbin so that the second cover member can be fitted between the inner peripheral surface of the second cover member and the outer peripheral surface of the circular recess. The current sensor according to claim 1, which is configured. 4. An end portion of the winding wound around the first winding frame portion of the first bobbin, and an end portion of the winding winding around the second winding frame portion of the second coil bobbin. The parts and the parts are arranged on the same plane in a state where they are connected in an annular shape.
The current sensor according to any one of 1 to 3. 5. The first winding frame portion and the second winding frame portion are each formed such that the average value of the cross-sectional areas of the both is equal to the cross-sectional area of the core material. Four
The current sensor according to any one of 1. 6. The current sensor according to claim 1, which is configured as a Rogowski coil.