JPH0815321A - Current sensor - Google Patents

Abstract

PURPOSE:To obtain a highly accurate current sensor by suppressing the effect of field generated from an objective conductor surrounded by a magnetic core or other external field. CONSTITUTION:The current sensor comprises a rectangular core 21 housing one core part 22 of substantially U-shape in one case part 13 of an opening/ closing magnetic shield case 12 and the other core part 26 of substantially U-shape in the other case part 14, respectively, through a resin material, and a flus gate type magnetic detection element 35 disposed closely to an air gap part 33 of the magnetic core 21. The magnetic detection element 35 is embedded in a recess 31 made at a position corresponding to the air gap part 33 in the outer periphery of the magnetic core 21. The magnetic shield case 12 covers only the required part of the magnetic core 21 and the magnetic detection element 35 has a structure excellent in the temperature characteristics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current sensor, and more specifically, it improves the measurement accuracy by making it difficult to be influenced by a magnetic field from a conductor to be measured enclosed by a magnetic core and other external magnetic fields. Current sensor that can be.

[0002]

2. Description of the Related Art Clamp-type ammeters and the like are constructed by incorporating a current sensor formed by freely enclosing a conductor to be measured so that it can be introduced by surrounding a conductor to be measured such as an electric wire.

FIG. 7 is a perspective view showing an outline of a magnetic shield case 1 which is divided into two parts which can be opened and closed in the above current sensor. The whole of the one side case part is made of a high magnetic permeability metal material such as permalloy. 2 and the other side case portion 3.

In this case, in particular, the other side case portion 3 has the opening 4 which is necessary for the relation with the connector or the like and has one side surface for introducing the conductor to be measured such as the electric wire to be measured, as is apparent from the illustrated example. While leaving the necessary space for each in the center,
It is formed with a wall surface having a surface area capable of reliably covering the side of the magnetic core over substantially the entire circumference.

On the other hand, FIG. 9 shows the above magnetic shield case 1.
FIG. 3 is an explanatory diagram showing a positional relationship between a magnetic core 5 housed and fixed in a magnetic core 5 and a flux gate type magnetic detection element 9 arranged in the vicinity of a void portion 8 of the magnetic core 5.

In the present specification, the term "fluxgate type magnetic detecting element" means "a so-called fluxgate type magnetic detecting element having an excitation winding and a detection winding, or a high magnetic permeability such as amorphous metal. A metal core is used as a magnetic core, and a detection coil that also serves as an excitation winding is attached to the magnetic core to form a pair. The detection windings that also serve as the excitation winding are connected to each other, and each winding changes depending on the applied magnetic field. The term "magnetic detection element formed so as to detect the difference in inductance as a magnetic flux".

In this case, the magnetic core 5 has a substantially U-shaped one-side core portion 6 housed in the one-side case portion 2 in FIG. The other side core portion 7 to be presented has a rectangular shape in the form of an enclosure.

The magnetic detecting element 9 is the magnetic core 5 described above.
Along the outer peripheral surface of the other side core portion 7 in
It is arranged in the vicinity of the above so as to be able to detect the leakage magnetic flux in the void portion 8. Although not shown in the drawing, the magnetic detection element 9 has an excitation winding bobbin inside, and a magnetic material strip made of an amorphous material or the like is provided in the excitation winding bobbin by an adhesive. It is installed in a fixed state.

[0009]

By the way, the magnetic shield case 1 shown in FIG. 7 can reduce the influence from the external magnetic field, and the magnetic core 5 shown in FIG.
The leakage magnetic flux can be detected depending on the positional relationship between the magnetic field sensor and the magnetic detection element 9.

However, the magnetic shield case 1 shown in FIG.
In particular, since the other side case portion 3 is formed with a wall surface having a surface area capable of reliably covering the side of the magnetic core 5 as shown in FIG. The magnetic field from the measurement conductor side easily flows into not only the magnetic core 5 side but also the other side case portion 3 side, and as a result, in the high frequency region where the magnetic permeability on the magnetic shield case 1 side deteriorates, All the magnetic field flowing on the side of the other case portion 3 flows into the side of the magnetic core 5 to increase the sensitivity, which has an adverse effect on the frequency characteristics.

On the other hand, in the case of the arrangement relationship between the magnetic core 5 and the magnetic detecting element 9 shown in FIG. 8, the magnetic detecting element 9 side has no barrier to be magnetically shielded and is easily exposed to an external magnetic field. There was a problem that was affected by it.

Further, the magnetic material strip held inside the exciting winding bobbin provided in the magnetic detecting element 9 is:
Since it is incorporated under the condition of being fixed by an adhesive, when the temperature changes and the side of the bobbin expands and contracts, stress is applied to the magnetic material strip side, and the temperature characteristics deteriorate. There was also an inconvenience.

[0013]

The present invention has been made in view of the above problems found in the prior art.
The structural feature of the invention according to claim 1 is that the one side core portion having a substantially U shape is provided in the one side case portion of the magnetic shield case which is openably / closably divided into two, and the substantially U shape is provided in the other side case portion. A rectangular magnetic core in the form of an enclosing frame formed by separately accommodating and fixing the other side core portions, each of which has a resin material, and a void portion provided in the magnetic core. In a current sensor including at least a flux gate type magnetic detection element, the magnetic detection element is embedded in a recess provided in a corresponding portion where the void is located from the outer peripheral side of the magnetic core. It is in.

A second aspect of the present invention is characterized in that a void portion formed between the divided end faces when the other-side core portion is divided into left and right symmetrical left and right side portions is located. The recessed portion according to claim 1 is provided in a portion to be formed.

Furthermore, the constitutional feature of the third aspect of the present invention is that the one side core portion and the other side core portion are divided into left and right symmetrical left and right side portions, respectively. The concave portions according to claim 1 are respectively provided at the portions where the voids formed as a pair are located therebetween.

Furthermore, the structural feature of the invention according to claim 4 is that when the other side core portion is biased to one side and is divided into a left side portion and a right side portion, it is located near the lower corner portion. The recessed portion according to claim 1 is provided in a portion where a void portion formed between the divided end surfaces is formed.

On the other hand, the constitutional feature of the fifth aspect of the present invention is that the one side core portion having a substantially U-shape is provided in the one side case portion of the magnetic shield case which is openable and closable.
A rectangular magnetic core in the shape of an enclosure formed by accommodating and fixing the other side core portions having a substantially U-shape inside the other side case portion through a resin material, and the magnetic cores provided in the magnetic core. In a current sensor including at least a flux gate type magnetic detection element disposed near the void, the magnetic shield case is made of a box-shaped high magnetic permeability magnetic material with one side surface opened. Along the long side edges of the one side case part and the rectangular bottom plate part, and the upper edge thereof is substantially level with the top surface position of the horizontal piece of the other side core part. The short standing piece to be erected should be placed along one of the short side edges, and the top edge should be approximately the same height as the top surface of the vertical piece on the other side core. Made of high-permeability magnetic metal material with long standing pieces that stand upright Side case part, the one side case part is inside a one side protective case made of corresponding non-magnetic material, and the other side case part is its bottom plate part, short standing piece part and long piece part. It has a wall surface that covers the respective facing surfaces of the long standing piece and the long standing piece, and can be housed in the other side protective case made of a non-magnetic material having the other two surfaces opened.

A sixth aspect of the present invention is characterized in that the one side core portion of the magnetic shield case, which is divided into two parts that can be opened and closed, has a substantially U-shaped one side core portion.
A rectangular magnetic core in the shape of an enclosure formed by accommodating and fixing the other side core portions having a substantially U-shape inside the other side case portion through a resin material, and the magnetic cores provided in the magnetic core. In a current sensor including at least a flux gate type magnetic detection element disposed near the void, the magnetic detection element includes a pair of winding bobbins and holes provided in the winding bobbins. Of the magnetic material strip having a length substantially equal to the depth of the magnetic material strip, and a case body provided with holes for accommodating the pair of winding bobbins from different directions. Each winding bobbin that is allowed to move freely and is inserted into the hole is formed by enclosing the lead wire in the hole of the case body so that the lead wire goes out.

[0019]

Therefore, according to the first aspect of the present invention, the magnetic detection element is provided from the outer peripheral side to the corresponding portion where the void portion is located in the magnetic core formed in the shape of an enclosure. Since it can be embedded in the recessed part, it is possible to suppress the influence from the external magnetic field.
The magnetic resistance of the magnetic core is increased by forming the recessed portion in the magnetic core at the position where the void portion is located. As a result, the magnetic flux density of the leakage magnetic flux is increased, and the detection sensitivity of the leakage magnetic flux by the magnetic detection element can be increased.

According to the second aspect of the invention, the void portion formed between the divided end faces when the other side core portion of the magnetic core is divided into left and right symmetrical left and right side portions is located. The recessed portion is provided at a portion to be formed.
In addition to the effects of the described invention, the left side portion and the right side portion forming the other side core portion can be formed by the same mold, and as a result, the manufacturing cost of the other side core portion can be reduced. .

Further, according to the third aspect of the present invention, when the one side core portion and the other side core portion constituting the magnetic core are divided into two symmetrical left and right side portions, respectively. Since the concave portions are provided at the portions where the voids formed as a pair are formed between the respective divided end faces, in addition to the effect of the invention of claim 1, the same as the invention of claim 2. The left side part and the right side part forming the other side core part can be formed by the same mold, and the left side part and the right side part forming the one side core part can be formed by the same mold. As a result, the manufacturing cost of the entire magnetic core can be reduced. In addition, the magnetic detection elements separately housed in each of the recesses are added in the direction of addition to the magnetic flux from the measured conductor that is enclosed by the magnetic core and penetrating therethrough, and in the direction of cancellation of the external magnetic field. Can be connected, so that the influence from the external magnetic field can be suppressed under a more preferable state.

Further, according to the invention as set forth in claim 4, when the other side core portion is biased to one side and is divided into a left side portion and a right side portion, the core portion is positioned near the lower corner portion. Since the recessed portion is provided in a portion where a void portion formed between the divided end surfaces is formed, the conductor to be measured enclosed in the other side core portion in addition to the effect of the invention according to claim 1. As a result of being able to arrange the magnetic detection element at a position farthest from the center point of the magnetic core, which is the ideal position, the magnetic effect from the conductor to be measured can be reduced.

On the other hand, according to the fifth aspect of the present invention, in the other side case portion constituting the magnetic shield case, the pair of short standing piece portions is provided on the side of the horizontal piece whose upper edge is the other side core portion. Since the surface area is reduced by shortening the rising dimension so that it is approximately the same height as the top surface position of the part, the magnetic field from the conductor to be measured hardly flows on the other side case part side,
In particular, in the high frequency region, the magnetic field flowing from the other case portion side to the magnetic core side can be reduced to suppress the influence on the frequency characteristic.

According to the sixth aspect of the present invention, each winding bobbin constituting the magnetic detection element is allowed to move freely in each hole without fixing the magnetic material strip with an adhesive or the like. Since it is inserted into the winding bobbin side even if the temperature changes and the winding bobbin side expands or contracts, no stress is applied to the magnetic material strips, and therefore the temperature characteristics can be improved. it can.

[0025]

FIG. 1 is an exploded perspective view showing an example of a schematic structure of a current sensor which constitutes the present invention.
A non-magnetic outer case 11 made up of one side protective case portion 11a and the other side protective case portion 11b divided into two parts, and a permalloy or the like made up of one side case portion 13 and the other side case portion 14 which are also divided in two. The magnetic shield case 12 made of a magnetic permeability magnetic metal material, the magnetic core 21 made of a high magnetic permeability magnetic metal material such as ferrite made of the one side core portion 22 and the other side core portion 26, and the other side core portion 26. It is configured to have a base part 45 made of a synthetic resin material or the like to be mounted together with the flux gate type magnetic detection element 35.

Of these, the magnetic shield case 12 is one side case part 1 accommodated on the side of the one side protection case part 11a.
3 and the other-side case portion 14 housed on the other-side protection case portion 11b side can be opened and closed freely.

Further, the one side core portion 22 having a substantially U shape is provided in the one side case portion 13 of the magnetic shield case 12, and the other side core portion having a substantially U shape is also provided in the other side case portion 14. 26 are respectively accommodated and fixed via a resin material, and each of the one side core portion 22 and the other side core portion 26 is made into an enclosing frame-like rectangular shape by abutting the corresponding end faces 21a, 26a. The magnetic core 21 is formed, and moreover, the void 33 provided in the magnetic core 21.
The magnetic detection element 35 is disposed in the vicinity of.

According to a first aspect of the present invention, the magnetic detection element 35 in the current sensor shown in FIG.
It is characterized in that it is embedded in a recessed portion 25 or 31 provided in the corresponding portion where the void 33 is located from the outer peripheral side of the magnetic core 21, specifically, the one side core portion 22 of the magnetic core 21.
At least one of the other side core portion 26 and the other side core portion 26 is divided into two according to the illustrated example to form a gap portion 33 between the divided end faces 30a and 30a. The peripheral portion where 33 is located is cut from the outer peripheral side so that a step having a depth that allows the magnetic detection element 35 to be embedded flush with the recessed portion 2 is formed.
5 and / or 31 are formed, and the magnetic detection element 35 is disposed in the recess 25 and / or 31.

In addition, according to the second aspect of the present invention, as shown in FIG. 2, the divided end surface 30 when the concave portion 31 is divided into the left side portion 27 and the right side portion 28 which are symmetrical with respect to the other side core portion 26.
It is characterized in that it is formed in a portion where the void 33 formed between a and 30a is located.

That is, the other side core portion 26 of the magnetic core 21 is formed in a substantially U shape by a pair of vertical piece portions 29, 29 and a horizontal piece portion 30 connecting the lower side portions of these vertical piece portions 29. The horizontal piece 30 is divided into two parts symmetrically by cutting the center position of the horizontal piece 30 while intersecting it in the length direction.

Moreover, the concave portion 31 has the horizontal piece 30.
Each of the lower corners in which the divided end faces 30a are located is cut symmetrically to form a rectangular groove centered on the void 33.

Further, according to the third aspect of the present invention, as shown in FIG. 3, the concave portions 25 and 31 are left and right symmetric with respect to the one side core portion 22 and the other side core portion, respectively. Each end face 2 when divided into two parts 22b and 28
It is characterized in that it is formed at a portion where the void 33 formed as a pair between 4, 24 and 31, 31 is located.

That is, the one side core portion 22 of the magnetic core 21 is formed in a substantially U shape by a pair of vertical piece portions 23, 23 and a horizontal piece portion 24 connecting the upper side portions of these vertical piece portions 23. The other side core portion 2
6 also has a pair of vertical pieces 29, 29 and these vertical pieces 2
It is formed in a substantially U shape with the horizontal piece portion 30 that connects the lower side portions of 9 together.

In this case, the one side core portion 22 and the other side core portion 2
The reference numeral 6 indicates that the horizontal pieces 24 and 30 are symmetrically cut into each other by intersecting the central positions of the horizontal pieces 24 and 30 in the lengthwise direction and are divided into two parts.

In addition, the concave portion 25 formed in the one side core portion 22 has the divided end faces 24a of the horizontal piece 24.
By severing each of the upper corners in which the positions are located symmetrically, the recessed portions 31 formed in the other side core portion 26 form the lower corners of the horizontal piece portion 30 where the respective split end surfaces 30a are located in the left and right sides. By cutting symmetrically, each of them is formed in a rectangular groove shape with the void portion 33 centered.

Furthermore, the invention according to claim 4 is as shown in FIG.
When the other side core portion 26 is biased to one side as shown in FIG. 2 and is divided into a left side portion 27 and a right side portion 28, it is located in the vicinity of the lower corner portion between the divided end faces 30a, 30a. It is characterized in that the recessed portion 31 is formed in a portion where the formed void portion 33 is located.

That is, the other side core portion 26 of the magnetic core 21 is substantially U-shaped by a pair of vertical piece portions 29, 29 and a horizontal piece portion 30 connecting the lower side portions of these vertical piece portions 29. And is formed so as to be asymmetrical by cutting one side of the horizontal piece 30, for example, a position biased to the right side as shown in the figure, crossing the lengthwise direction and cutting. It is divided.

Moreover, the concave portion 31 has the horizontal piece portion 30.
Each of the lower corners in which the divided end faces 30a are located is cut symmetrically to form a rectangular groove centered on the void 33.

On the other hand, according to the invention of claim 5, the magnetic shield case 12 in the current sensor shown in FIG.
The feature is that it is formed as shown in FIG.

That is, the magnetic shield case 12
As shown in FIG. 1, one side case portion 1 made of a high magnetic permeability magnetic metal material having a box shape with one side surface opened.
3 along the both side edges on the long side of the rectangular bottom plate portion 15, and the upper edge 16a thereof is substantially level with the top surface position of the horizontal piece portion 30 of the other side core portion 26. The short standing piece 16 that is erected and one of the short sides, for example, along the side edge of the short side located on the left side as in the illustrated example, and the top edge 17a thereof is the other side core. The other side case portion 14 made of a high-permeability magnetic metal material having a long standing piece 17 that is erected at substantially the same height as the top surface of the vertical piece 29 of the portion 26. Has been done.

Moreover, as shown in FIG. 1, the one-side case portion 13 and the bottom-side plate portion 15 of the other-side case portion 14 correspond to the corresponding non-magnetically permeable one-side protective case 11a. The short standing piece 16 and the long standing piece 17 have wall surfaces that cover the opposing surfaces, and the other two surfaces are open so that they can be housed in the other non-permeable magnetic protection case 11b. The whole is formed.

The invention according to claim 6 is characterized in that the magnetic detection element 35 in the current sensor shown in FIG. 1 is formed under the flux gate type as shown in FIG.

That is, the magnetic detection element 35 has a pair of winding bobbins 3 in which bobbins 37 and 37 'are provided with windings 38 and 38' which function as detection windings which also function as excitation windings.
6, 36 ', and magnetic material strips 40, 40' composed of amorphous strips having a length approximately the same as the depth of the holes 39 provided in the winding bobbins 36, 36 ', and the pair of Case body 41 formed of a non-conductive member such as a synthetic resin in which a pair of holes 42, 42 for accommodating the winding bobbins 36, 36 ′ of the above-mentioned winding bobbins 36, 36 ′ in different directions are provided separately in the length direction thereof. It consists of and. Note that FIG.
FIG. 8 shows a circuit configuration diagram of the magnetic detection element 35.

In this case, the magnetic material strips 40, 40 'such as amorphous strips are provided in the holes 3 of the winding bobbins 36, 36'.
The winding bobbins 36, 36 ', which are held by being loosely inserted into the shaft 9 and thus holding the magnetic material strips 40, 40' in the hole 42 of the case body 41, The so-called flux gate type magnetic detection element 35 is formed by inserting the lead wires 38a in a staggered state and inserting the lead wires 38a from the alternate directions, and then closing and closing the holes 42.

Since the present invention is configured as described above, according to the invention of claim 1, the magnetic detecting element 35 is formed in the shape of a frame, and the void portion in the magnetic core 21 is formed. Since the magnetic core 21 can be buried flush with the recessed portions 25 and / or 31 provided from the outer peripheral side of the corresponding portion where the magnetic core 33 is located, the magnetic detection element 35 can be formed by using the magnetic core 21 as a barrier. The influence of the external magnetic field on the magnetic field can be suppressed.

Moreover, since the concave portions 25 and / or 31 in which the magnetic detecting element 35 is disposed are formed in the magnetic core 21 at the positions where the voids 33 are located, the portions where the voids 33 are located are located. The diameter is reduced to increase the magnetic resistance, and the magnetic flux density of the leakage magnetic flux is also increased in response to this, and the detection sensitivity of the leakage magnetic flux by the magnetic detection element 35 can be increased.

Further, according to the invention of claim 2, FIG.
As shown in FIG. 5, when the other side core portion 26 of the magnetic core 21 is divided into left and right symmetrical side portions 27 and 28, a space 33 formed between the divided end surfaces 30a and 30a is located at a position. Since the concave portion 31 is provided, in addition to the effect of the invention according to claim 1, the other side core portion 26 is provided.
As a result of being able to form the left side portion 27 and the right side portion 28 constituting the same mold with the same mold, it is possible to contribute to the reduction of the manufacturing cost of the other side core portion 26.

Further, according to the third aspect of the invention, as shown in FIG. 3, the one side core portion 22 and the other side core portion 26 forming the magnetic core 21 are symmetrical with each other on the left side portion 22a. , 28 and the right side portions 22b, 28 are divided into two, and the recessed portions 25, 31 are formed at the portions where the cavities 33 formed in pairs are formed between the divided end surfaces 24a, 24 and 30a, 30a. Since they are respectively provided, in addition to the effect of the invention described in claim 1, the left side portion 27 and the right side portion 28 forming the other side core portion 26 are formed in the same mold in the same manner as the invention described in claim 2. The left side portion 22a and the right side portion 22b forming the one side core portion 22 can be formed by
Since and can be formed by the same mold, it is possible to contribute to the reduction of the manufacturing cost of the entire magnetic core 21 as a result.

In addition, the magnetic detecting element 35, which is separately housed in each of the recesses 25 and 31, is provided with the magnetic core 2.
Since it is possible to connect the magnetic fluxes from the conductor to be measured C such as a non-measurement electric wire which is enclosed and penetrated by 1 in the direction of addition and in the direction of canceling the external magnetic field, the external magnetic field can be connected. Can be suppressed under a more preferable condition.

Further, according to the invention described in claim 4, when the other side core portion 26 is biased to one side as shown in FIG. 4 and divided into a left side portion 27 and a right side portion 28. The divided end faces 30a, 3 that will be located near the lower corner
Since the recessed portion 31 is provided at a position where the void portion 33 formed between 0a is located, in addition to the function and effect of the invention described in claim 1, the other side core portion 26 is surrounded and enclosed. The center point O of the magnetic core, which is the ideal position of the measurement conductor C
The magnetic detection element 35 can be arranged at a position where the straight line distance L from is the longest or longer.

Therefore, the magnetic detection element 35 can be disposed in the recess 31 of the magnetic core 21 while being less affected by the magnetic effect from the conductor C to be measured.

On the other hand, according to the fifth aspect of the present invention, the other side case portion 14 made of the high-permeability magnetic metal material has a pair of short standing pieces 16 as is apparent from FIGS. 1 and 5. Since the surface area is reduced by shortening the rising dimension so that the upper edge 16a thereof is substantially at the same height as the top surface position of the horizontal piece portion 30 of the other side core portion 26, the measurement target enclosed is The magnetic field from the conductor C side is less likely to flow on the side of the other case portion 26 as a result, and as a result, the other case portion 2 in the high frequency region where the magnetic permeability on the magnetic shield case 12 side is deteriorated.
By reducing the magnetic field flowing from the side of 6 to the side of the magnetic core 21, it is possible to suppress the influence on the frequency characteristic.

According to the sixth aspect of the present invention, each winding bobbin 36, 3 forming the magnetic detection element 35.
As shown in FIG. 6, since the magnetic material strips 40 and 40 'are movably inserted into the respective hole portions 39 without being fixed with an adhesive or the like, as shown in FIG. Even if the wire bobbins 36, 36 'expand or contract,
The magnetic material strips 40, 40 'can be freely deformed following the stress-free side, and therefore, the flux gate type magnetic sensing element 3 having excellent temperature characteristics can be obtained.
5 can be formed.

[0054]

As described above, according to the first aspect of the present invention, the magnetic detecting element has a structure in which the void portion is located in the magnetic core formed in the shape of an enclosure. Since it can be embedded in the concave part provided from the outer peripheral side of the part, it is possible to suppress the influence from the external magnetic field and form the concave part in the part where the void part is located in the magnetic core. As a result, the magnetic resistance increases, and as a result, the magnetic flux density of the leakage magnetic flux also increases, and the leakage magnetic flux detection sensitivity of the magnetic detection element can be increased.

According to the second aspect of the present invention, the void portion formed between the divided end faces when the other side core portion of the magnetic core is divided into left and right symmetrical left and right side portions is located. The recessed portion is provided at a portion to be formed.
In addition to the effects of the described invention, the left side portion and the right side portion forming the other side core portion can be formed by the same mold, and as a result, the manufacturing cost of the other side core portion can be reduced. .

Further, according to the third aspect of the present invention, when the one side core portion and the other side core portion constituting the magnetic core are divided into left and right symmetrical left and right side portions, respectively. Since the concave portions are provided at the portions where the voids formed as a pair are formed between the respective divided end faces, in addition to the effect of the invention of claim 1, the same as the invention of claim 2. The left side part and the right side part forming the other side core part can be formed by the same mold, and the left side part and the right side part forming the one side core part can be formed by the same mold. As a result, the manufacturing cost of the entire magnetic core can be reduced. In addition, the magnetic detection elements separately housed in each of the recesses are added in the direction of addition to the magnetic flux from the measured conductor that is enclosed by the magnetic core and penetrating therethrough, and in the direction of cancellation of the external magnetic field. Can be connected, so that the influence from the external magnetic field can be suppressed under a more preferable state.

Further, according to the invention as set forth in claim 4, when the other side core portion is biased to one side and is divided into a left side portion and a right side portion, the core portion is located near the lower corner portion. Since the recessed portion is provided in a portion where a void portion formed between the divided end surfaces is formed, the conductor to be measured enclosed in the other side core portion in addition to the effect of the invention according to claim 1. As a result, the magnetic detection element can be arranged at a position farthest from the center point of the magnetic core, which is the ideal position, so that the magnetic effect from the conductor to be measured can be reduced.

On the other hand, according to the fifth aspect of the present invention, the other side case portion constituting the magnetic wound case has a pair of short standing pieces on the side thereof, and the upper edge thereof is horizontal to the other side core portion. Since the surface area is made smaller by shortening the rising dimension so that it is approximately the same height as the top surface position of one side, the magnetic field from the conductor to be measured is less likely to flow on the side of the side case, which is especially high. In the frequency region, it is possible to reduce the magnetic field flowing from the other case portion side to the magnetic core side to suppress the influence on the frequency characteristic.

Further, according to the invention of claim 6, each winding bobbin constituting the magnetic detecting element is allowed to move freely in each hole without fixing the magnetic material strip with an adhesive or the like. Since it is inserted into the winding bobbin side even if the temperature changes and the winding bobbin side expands or contracts, no stress is applied to the magnetic material strips, and therefore the temperature characteristics can be improved. it can.

[Brief description of drawings]

FIG. 1 is an exploded perspective view illustrating a schematic configuration of a current sensor that constitutes the present invention.

FIG. 2 is an explanatory diagram illustrating an arrangement relationship between a magnetic core and a magnetic detection element corresponding to the invention of claim 2;

FIG. 3 is an explanatory diagram illustrating an arrangement relationship between a magnetic core and a magnetic detection element corresponding to the invention of claim 3;

FIG. 4 is an explanatory diagram illustrating an arrangement relationship between a magnetic core and a magnetic detection element corresponding to the invention of claim 4;

FIG. 5 is an explanatory diagram illustrating an arrangement relationship between a magnetic shield case and a magnetic core corresponding to the invention of claim 5;

FIG. 6 is an explanatory diagram showing an embodiment of a magnetic detection element corresponding to the invention of claim 6;

FIG. 7 is an exploded perspective view showing an example of an external configuration of a conventional magnetic shield case for a current sensor.

FIG. 8 is a circuit configuration diagram of the magnetic detection element shown in FIG.

FIG. 9 is an explanatory diagram showing an arrangement relationship between a magnetic core and a magnetic detection element as a conventional example.

[Explanation of symbols]

 11 non-magnetic outer case 11a one side protection case 11b other side protection case 12 magnetic shield case 13 one side case part 14 other side case part 15 bottom plate part 16 short standing piece 16a upper edge 17 long standing piece 17a top edge 21 magnetic core 21a end face 22 one side core part 22a left side part 22b right side part 23 vertical piece part 24 horizontal piece part 24a split end face 25 concave part 26 other side core part 26a end face 27 left side part 28 right side part 29 vertical piece part 30 horizontal piece Part 30a Split end face 31 Recessed part 33 Void part 35 Magnetic detection element 36, 36 'Winding bobbin 37, 37' Bobbin 38, 38 'Winding 38a Lead wire 39 Hole part 40 Magnetic material strip 41 Case body part 42 Hole part 45 Base C Conductor to be measured

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H01L 43/00 (72) Inventor Akihiro Nagai 81 Sakurazamachi, Oizumi, Ueda-shi, Nagano Within

Claims (6)

[Claims] 1. A magnetic shield case, which is divided into two parts that can be opened and closed, has a substantially U-shaped one side core portion inside one side case portion, and a substantially U-shaped other side core portion inside the other side case portion. An angular frame-shaped magnetic core formed by accommodating and fixing each separately through a resin material, and a fluxgate type magnetic detection element arranged in the vicinity of a void portion provided in the magnetic core In the current sensor including at least, the magnetic detection element is embedded in a recess provided in a corresponding portion where the void is located from the outer peripheral side of the magnetic core. 2. The recessed portion of the magnetic core is provided at a position where a void portion is formed between divided end faces when the other-side core portion is divided into left and right symmetrical left and right side portions. The current sensor according to claim 1, wherein: 3. The recessed portion of the magnetic core forms a pair between the divided end faces when the one side core portion and the other side core portion are divided into two symmetrical left and right side portions. The current sensor according to claim 1, wherein the current sensor is provided in each of the regions where the voids formed as a result are located. 4. The split end surface of the magnetic core, which is located near the lower corner when the other side core portion is biased to one side and is split into a left side portion and a right side portion. The current sensor according to claim 1, wherein the current sensor is provided at a position where a void portion formed between them is located. 5. A substantially U-shaped one side core portion in the one side case portion of the openable / closable magnetic shield case, and a substantially U-shaped other side core portion in the other side case portion, respectively. An angular frame-shaped magnetic core formed by accommodating and fixing each separately via a resin material, and a fluxgate type magnetic detection element disposed in the vicinity of a void portion provided in the magnetic core In the current sensor comprising at least, the magnetic shield case has a one-sided case portion made of a high-permeability magnetic metal material having a box shape with one side open, and a long side of a rectangular bottom plate portion. A short standing piece that is erected along both edges, with its upper edge approximately at the same height as the top surface of the horizontal piece of the other side core, and one of the short sides Along the side edge and the top edge is on the other side The other side case portion made of a high-permeability magnetic metal material having a long standing piece portion that is erected so as to be substantially the same height as the top surface position of the vertical piece portion of the core portion,
The one-side case portion is formed in a corresponding one-side protective case made of non-magnetic material, and the other-side case portion includes a bottom plate portion, a short standing piece, a long standing piece, and a long standing piece. A current sensor characterized in that it has a wall surface that covers each facing surface, and is formed so that it can be housed in each of the other side protective cases made of a non-magnetic material having the other two surfaces opened. 6. A substantially U-shaped one-side core portion in one side case portion of the openable and closable magnetic shield case, and another side-side core portion having a substantially U-shape in the other side case portion. An angular frame-shaped magnetic core formed by accommodating and fixing each separately through a resin material, and a fluxgate type magnetic detection element arranged in the vicinity of a void portion provided in the magnetic core In the current sensor comprising at least, the magnetic detection element, a pair of winding bobbins, a magnetic material strip having a length substantially the same as the depth of the holes provided in these winding bobbins, And a case main body provided with holes for accommodating the pair of winding bobbins from opposite directions, and each winding bobbin in which the magnetic material strip is allowed to move freely and is inserted into the holes. In the hole part A current sensor characterized in that it is formed by letting out the lead wire and enclosing it.