JP2010281705A - Clamp sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress external noise such as common mode noise to a lower level. <P>SOLUTION: A one-side sensor head 11 includes: a one-side outer shield case part 12; a one-side inner shield case part 13 stored therein, for storing a one-side core part 17; and one-side spacers 14, 15 disposed in the one-side outer shield case part 12 in the interposed state between the one-side outer shield case part 12 and the one-side inner shield case part 13. An other-side sensor head 21 includes: an other-side outer shield case part 22; an other-side inner shield case part 23 stored therein, for storing an other-side core part 27; and other-side spacers 24, 25 disposed in the other-side outer shield case part 22 in the interposed state between the other-side outer shield case part 22 and the other-side inner shield case part 23. Elastic tongue pieces 14d, 15d, 24d, 25d are formed on the one-side spacers 14, 15 and the other-side spacers 24, 25. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a clamp sensor in which a shield case is disposed in a double structure so as to cover a magnetic core.

  As this type of clamp sensor, the applicant has already proposed a clamp sensor disclosed in Patent Document 1 below. This clamp sensor includes a one-side sensor head and an other-side sensor head that are configured so that a conductor to be measured can be inserted into and removed from a clamp measurement window (insertion hole for the conductor to be measured). The one-side shield case consisting of a side outer case part and one side inner case part, the one side core part placed in the one side inner case part, and the accommodation position of the one side inner case part within the one side outer case part are regulated. At least one side spacer, and one side partition wall portion which is one side of the clamp measurement window, and the other side sensor head includes an other side shield case composed of the other side outer case portion and the other side inner case portion. The other side core part placed in the other side inner case part, the other side spacer that regulates the accommodation position of the other side inner case part within the other side outer case part, and the other side of the clamp measurement window It is comprised by the side partition part.

  According to this clamp sensor, by interposing the one side spacer and the other side spacer, the one side inner case part constituting the one side shield case at the time of measurement, and the other side constituting the other side shield case Since the side inner case portion can be brought into contact with each other under the positional relationship in which the open end faces face each other, the shielding effect against the external magnetic field and electric field can be ensured. Also, the one-side spacer is brought into surface contact with the one-side outer case portion and the one-side inner case portion to ensure electrical conduction, and the other-side spacer is in surface contact with the other-side outer case portion and the other-side inner case portion. Thus, it is possible to effectively suppress the influence of external noise such as common mode noise by electrically conducting each of them.

Japanese Patent Laying-Open No. 2005-37284 (page 4-7, FIG. 1)

  However, as a result of studying the clamp sensor described above, the clamp sensor is interposed between the outer case portion on one side and the inner case portion on one side due to the plate thickness of each member such as both spacers and the dimensional tolerance during manufacture. In addition, the contact state of the one side spacer with respect to both the case portions and the contact state of the other side spacer interposed between the other side outer case portion and the other side inner case portion with respect to the both case portions may be insufficient. In this case, the continuity between the one outer case part and the one inner case part or the conduction between the other outer case part and the other inner case part is not sufficient. The present inventors have found that there is a problem to be solved that it is difficult to suppress external noise such as common mode noise to a desired level.

  The present invention has been made to solve such a problem, and a main object of the present invention is to provide a clamp sensor that can always suppress external noise such as common mode noise to a lower level.

  In order to achieve the above object, a clamp sensor according to claim 1 is provided with a one-side sensor head that accommodates the one-side core portion and an other-side sensor head that accommodates the other-side core portion, and the one-side sensor head and the other In a state in which the side sensor head is disposed to be opposed, the one-side core portion and the other-side core portion constitute a magnetic closed circuit and surround the conductor to be detected, and the one-side sensor head is A box-shaped one-side outer shield case portion that is open on one side located on the side facing the other-side sensor head, is accommodated in the one-side outer shield case portion, and is identical to the one-surface side of the one-side outer shield case portion One side inner shield case part that is formed in a box shape that opens on one side in the direction and that houses the one side core part, and the one side outer shield case part in the one side outer shield case part, One side spacer which is disposed in a state of being interposed between the one side inner shield case part and which defines the accommodation position of the one side inner shield case part with respect to the one side outer shield case part, The side sensor head is housed in the other side outer shield case part, the other side outer shield case part that is open on one side located on the side facing the one side sensor head, and the other side outer shield case part. The other side outer shield case part in the other side outer shield case part, and the other side inner shield case part that is formed in a box shape in which one side in the same direction as the one side is open, An other-side spacer that is disposed between the other-side inner shield case part and that defines the accommodation position of the other-side inner shield case part with respect to the other-side outer shield case part. And, at least one spacer of said one side spacer and the other side spacer is resilient tongue by a part of the at least one spacer is cut and raised is formed.

  Further, the clamp sensor according to claim 2 is the clamp sensor according to claim 1, wherein the one side spacer and the other side spacer are respectively cut and raised so that the elastic tongue pieces are respectively raised and raised. Is formed.

  The clamp sensor according to claim 3 is the clamp sensor according to claim 1 or 2, wherein the one-side inner shield case portion and the one-side core portion, and the other-side inner shield case portion and the other The electroconductive connection member arrange | positioned by at least one between the side core parts is provided.

  According to the clamp sensor of the first aspect, by forming an elastic tongue piece on at least one of the one side spacer and the other side spacer, one of the one side and the other side on which the spacer is disposed. Since the electrical connection state (conduction state) between one outer shield case part and the inner shield case part is maintained in a good state by the elastic tongue piece, the contact between the outer shield case part and the inner shield case part is poor. Can be surely avoided, and the respective electric potentials of the outer shield case portion and the inner shield case portion on the side where the spacers on which the elastic tongues are formed are disposed, and the outer shield case portion and the inner shield case portion are in contact with each other. Each potential of the other outer shield case portion and the inner shield case portion can be reliably set to a predetermined potential (for example, a ground potential). Therefore, according to this clamp sensor, it is possible to always suppress external noise such as common mode noise to a desired level. As a result, it is possible to further improve the current detection accuracy of the detected conductor.

  According to the clamp sensor of the second aspect, the elastic tongue pieces are formed on both the one-side spacer and the other-side spacer, so that the electrical connection between the one-side outer shield case portion and the one-side inner shield case portion is achieved. The state (conduction state) and the electrical connection state (conduction state) between the other side outer shield case part and the other side inner shield case part are reliably maintained in a good state by the respective elastic tongue pieces. The outer shield case, the inner shield case on the one side, the outer shield case on the other side, and the inner shield case on the other side can be more reliably regulated to a predetermined potential. The level can be more reliably suppressed to the level, and the current detection accuracy of the detected conductor can be further improved.

  According to the clamp sensor according to claim 3, since the conductive connection member is provided, at least one of the core portions contacting the conductive connection member of the one-side core portion and the other-side core portion is shielded. The current can be regulated to the same predetermined potential as that of one part, and the other core part that is in contact with this one core part can also be prescribed to a predetermined potential, further improving the current detection accuracy of the conductor to be detected. Can be made.

3 is a side view showing the configuration of the clamp sensor 1. FIG. It is sectional drawing along the longitudinal direction of the main body case 2 for demonstrating the internal structure of the sensor main-body part 4 in the clamp sensor 1. FIG. FIG. 3 is an exploded perspective view for explaining the structure of a sensor body 4. It is a frequency characteristic figure of the common mode noise voltage ratio with respect to a probe output voltage.

  Hereinafter, embodiments of a clamp sensor will be described with reference to the accompanying drawings.

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

  The clamp sensor 1 shown in FIG. 1 is a slide type clamp sensor, and is slidable along the longitudinal direction with respect to the main body case 2 used as a grip portion having an elongated outer shape. A current that flows through a detected conductor 6 that is provided with a mounted slide case 3 and a sensor main body 4 and that is inserted into an insertion hole 5 that is open on the distal end side (the left end side in the figure) of the main body case 2. Is configured to be detectable.

  As shown in FIG. 1, the sensor main body 4 includes a one-side sensor head 11 accommodated on the distal end side of the slide case 3 and an other-side sensor head 21 accommodated on the distal end side of the main body case 2. Yes. As shown in the drawing, the one-side sensor head 11 and the other-side sensor head 21 are arranged to face each other when the slide case 3 is slid to the tip end side of the main body case 2 (clamped state). The insertion hole 5 is formed between them.

  As shown in FIGS. 2 and 3, the one-side sensor head 11 includes a one-side outer shield case portion 12, a one-side inner shield case portion 13, a pair of one-side spacers 14 and 15, a conductive connection member 16, and a one-side core. A part 17 and a one-side partition part 18 are provided. Specifically, the one-side outer shield case portion 12 uses a high-permeability alloy material such as a permalloy material, and opens on one surface side (the lower surface side in the figure) located on the side facing the other-side sensor head 21. It is formed in a box shape (cuboid shape), that is, a rectangular container shape. In addition, the pair of side walls 12a and 12b parallel to the longitudinal direction (direction X indicated by the arrow) of the main body case 2 in the one-side outer shield case portion 12 is a rectangular shape that fits with the end portion of the one-side partition wall portion 18. The notches 12c are respectively formed.

  The one-side inner shield case portion 13 is made of a high permeability alloy material such as a permalloy material, as shown in FIG. 3, on one side located on the side facing the other-side sensor head 21 (lower surface side in the figure). Is formed in a box shape (cuboid shape), that is, a rectangular container shape. In addition, a rectangular notch 13c that fits with an end of the one-side partition wall 18 is formed on the pair of side walls 13a and 13b parallel to the longitudinal direction (direction X) of the main body case 2 in the one-side inner shield case 13. (The same shape as the notch 12c) is formed. The one-side inner shield case portion 13 is formed smaller than the one-side outer shield case portion 12 and is configured to be accommodated in the one-side outer shield case portion 12. As an example, the outer dimension in the width direction (direction Y perpendicular to the direction X) of the one-side inner shield case portion 13 is twice the thickness t of the one-side spacers 14 and 15 added to this outer dimension. The length is defined as a length that substantially matches the inner dimension of the one-side outer shield case portion 12 in the width direction (direction Y). The outer dimension of the one-side inner shield case 13 in the height direction (direction Z orthogonal to the directions X and Y) is equal to the length obtained by adding the plate thickness t of the one-side spacers 14 and 15 to this outer dimension. It is defined as a length that substantially matches the inner dimension of the side outer shield case portion 12 in the height direction (direction Z).

  As shown in FIG. 3, the one-side spacers 14 and 15 are made of, for example, a metal plate having a uniform thickness t (a plate made of a nonmagnetic and conductive metal material such as bronze, copper, or aluminum). It is configured in a plane-symmetric shape. Specifically, the one-side spacer 14 is connected to the side wall 13a of the one-side inner shield case portion 13 in contact with the first wall portion 14a, and is connected to the first wall portion 14a at a right angle to thereby form the one-side inner shield. The tip of the slide case 3 in the one-side inner shield case part 13 is connected to the second wall part 14b disposed in contact with the wall part 13d on the other surface side of the case part 13 and the first wall part 14a at a right angle. The third wall portion 14c is provided in contact with the wall portion 13e on the portion side. The one side spacer 14 is formed with one elastic tongue piece 14d as an example by cutting and raising a part of the one side spacer 14 (in this example, a part of the first wall portion 14a as an example). . Specifically, the elastic tongue piece 14d is formed by raising a tongue-like portion sandwiched between a pair of slits 14e formed in the first wall portion 14a. Note that the elastic tongue piece may be formed by cutting and raising a part of the second wall portion 14b or the third wall portion 14c other than the first wall portion 14a. The other one side spacer 15 is connected at right angles to the first wall portion 15a and the first wall portion 15a disposed in contact with the side wall 13b of the one side inner shield case portion 13, so that the one side inner shield case portion 13 is connected. Are connected at right angles to the second wall portion 15b disposed in contact with the wall portion 13d on the other surface side, and the first wall portion 15a. A third wall portion 15c disposed in contact with the wall portion 13e is provided. The one side spacer 15 is formed with one elastic tongue piece 15d as an example by cutting and raising a part of the one side spacer 15 (in this example, a part of the first wall portion 15a). . Specifically, the elastic tongue piece 15d is formed by raising a tongue-like portion sandwiched between a pair of slits 15e formed in the first wall portion 15a. Note that the elastic tongue piece may be formed by cutting and raising a part of the second wall portion 15b or the third wall portion 15c other than the first wall portion 15a.

  The conductive connecting member 16 is formed of an elastic body whose surface is subjected to conductive processing, and is disposed between the one-side core portion 17 and the one-side inner shield case portion 13 as shown in FIG. ing. As an example of the conductive connecting member 16, a product name “Shinetsu interconnector” manufactured by Shin-Etsu Polymer Co., Ltd., which is formed by arranging gold-plated metal thin wires at a low pitch on the surface of a U-shaped insulating sponge silicone rubber. Can be used.

  The one side core part 17 is comprised with the U-shaped core formed using magnetic materials, such as a ferrite. The one-side partition wall portion 18 is made of an electrically insulating material such as a synthetic resin material, and is positioned with respect to the one-side core portion 17 and the one-side inner shield case portion 13 with respect to the one-side outer shield case portion 12. It has a function to define (position). Specifically, the one-side partition wall 18 includes a plate body 18a in which the cross-sectional shape of both ends is the same shape (complementary shape) as the cutout portion 12c and the cutout portion 13c, and the other side sensor in the plate body 18a. It is composed of a pair of support walls 18b, 18b that are erected at a right angle on the non-opposing surface (upper surface in the figure) with respect to the head 21 with the width of the one side core portion 17 therebetween.

  The one-side outer shield case portion 12, the one-side inner shield case portion 13, the pair of one-side spacers 14 and 15, the conductive connecting member 16, the one-side core portion 17, and the one-side partition portion 18 configured as described above are provided. As shown in FIG. 3, first, the one-side core portion 17 is fitted between the pair of support walls 18 b and 18 b of the one-side partition wall portion 18, and then the one-side inner shield case portion 13 of the one-side core portion 17. With the conductive connection member 16 disposed on the side surface (the upper surface in the figure), the pair of support walls 18b and 18b and the one-side core portion 17 of the one-side partition wall portion 18 are connected to the one-side inner shield case portion 13. The both ends of the plate 18 a of the one-side partition wall 18 are fitted into the respective notches 13 c of the one-side inner shield case 13 while being accommodated in the inside. Subsequently, the one side spacers 14 and 15 are arranged in the one side inner shield case part 13, and in this state, the one side inner shield case part 13, the pair of one side spacers 14 and 15, the conductive connection member 16, one The side core portion 17 and the one-side partition wall portion 18 are accommodated in the one-side outer shield case portion 12, and both end portions of the plate body 18 a of the one-side partition wall portion 18 are used as the notches 12 c of the one-side outer shield case portion 12. Fit. Thereby, the accommodation position of the one-side inner shield case part 13 with respect to the one-side outer shield case part 12 and the one-side partition part with respect to the one-side outer shield case part 12 by the end portions of the plate body 18a of the one-side partition part 18 18, and thus the accommodation position in the one-side outer shield case portion 12 that fits with the one-side partition wall portion 18 is defined. Finally, resin is injected into the one-side outer shield case portion 12, and the one-side inner shield case portion 13 accommodated in the one-side outer shield case portion 12, the pair of one-side spacers 14 and 15, and the conductivity The connecting member 16, the one-side core portion 17, and the one-side partition wall portion 18 are fixed to the one-side outer shield case portion 12. Thereby, the one side sensor head 11 is completed.

  In the one-side sensor head 11 in this state, as shown in FIG. 2, the one-side spacer 15 is in close contact with the inner surface of the one-side outer shield case portion 12 and is electrically connected to each other (not shown in the figure). The one-side spacer 14 is also electrically connected to the one-side outer shield case portion 12 in the same manner as the one-side spacer 15), and the one-side inner shield case portion 13 is in close contact with the one-side spacer 15 and is electrically connected. The one-side core portion 17 is electrically connected to the one-side inner shield case portion 13 through the conductive connection member 16. Further, in the one-side sensor head 11, the elastic tongue pieces 14 d and 15 d formed on the one-side spacers 14 and 15 are pushed back against the elastic force and are one with the one-side outer shield case portion 12. Since it is disposed between the inner shield case part 13 and the one side outer shield case part 12 and the one side spacers 14 and 15, and the one side spacers 14 and 15 and the one side inside A state in which sufficient electrical contact with the shield case portion 13 is ensured, that is, the one-side core portion 17, the one-side inner shield case portion 13 and the one-side outer shield case portion 12 are in good electrical contact. It is in a state (good conduction state).

  As shown in FIG. 2, in the one-side sensor head 11, the side surfaces 12 a, 12 b of the one-side outer shield case portion 12 on the side facing the other-side sensor head 21 (the notch portion 12 c in FIG. The lower end surface), and the end surface (the lower end surface in the figure) of the other pair of side walls 12d and 12e orthogonal to the side walls 12a and 12b that face the other side sensor head 21 are one side inner shield case End surfaces of the side walls 13a, 13b, 13e of the portion 13 on the side facing the other side sensor head 21 (lower end surface in the figure), and end surfaces of the leg portions 17a in the one side core portion 17 (other side sensor head 21) And the end surface on the side facing (the lower end surface in the figure).

  As shown in FIGS. 2 and 3, the other-side sensor head 21 includes the other-side outer shield case portion 22, the other-side inner shield case portion 23, a pair of other-side spacers 24 and 25, a conductive connection member 26, and the other-side core. Part 27, other side partition part 28, detection coil 29, and connector part 30. Specifically, the other-side outer shield case portion 22 is made of a high-permeability alloy material such as a permalloy material, as shown in FIG. 3, on one side located on the side facing the one-side sensor head 11 (the same figure). Is formed in a box shape (rectangular shape) that is open, that is, a rectangular container shape, and is grounded. As an example, as shown in FIG. 1, the other-side outer shield case portion 22 includes a wiring member W1 disposed in the slide case 3 as an example, and a cable 7 to which the wiring member W1 is connected (not shown). The ground potential is defined by being grounded through a shield (for example, a net shield) and various measurement devices such as a waveform display device such as an oscilloscope to which the cable 7 is connected. In addition, it can replace with the wiring material W1 and the structure which connects the other side outer shield case part 22 to the shield in the cable 7 via the shield board arrange | positioned in the slide case 3 is also employable. Further, as shown in FIGS. 2 and 3, the other side partition wall portion 28 is formed on the pair of side walls 22 a and 22 b parallel to the longitudinal direction (direction X indicated by the arrow) of the main body case 2 in the other side outer shield case portion 22. A U-shaped notch 22c that fits with the end of each is formed. An insertion hole 22 f for the connector portion 30 is opened in the side wall 22 e located on the rear end side of the main body case 2 in the other side outer shield case portion 22. The other side outer shield case portion 22 is formed such that the thickness of each side wall 22a, 22b, 22d, 22e is the same as the thickness of each side wall 12a, 12b, 12d, 12e of the one side outer shield case portion 12, The interval between the side walls 22a and 22b is defined to be the same as the interval between the side walls 12a and 12b, and the interval between the side walls 22d and 22e is defined to be the same as the interval between the side walls 12d and 12e.

  The other-side inner shield case portion 23 is made of a high permeability alloy material such as a permalloy material, as shown in FIG. 3, on one side located on the side facing the one-side sensor head 11 (upper surface side in the figure). Is formed in a box shape (cuboid shape), that is, a rectangular container shape. In this example, the other-side inner shield case portion 23 is configured to be open on the one surface side located on the rear end side (connector portion 30 side) of the main body case 2. Further, a U-shaped notch that fits with an end of the other-side partition wall 28 is formed on the pair of side walls 23 a and 23 b parallel to the longitudinal direction (direction X) of the main body case 2 in the other-side inner shield case 23. 23c (the same shape as the notch 22c) is formed. The other-side inner shield case portion 23 is formed smaller than the other-side outer shield case portion 22 and is configured to be accommodated in the other-side outer shield case portion 22. As an example, the outer dimension in the width direction (direction Y orthogonal to the direction X) of the other-side inner shield case portion 23 is twice the thickness t of the other-side spacers 24, 25. The length is defined as a length that substantially matches the inner dimension in the width direction (direction Y) of the other outer shield case portion 22. Further, the outer dimension of the other inner shield case portion 23 in the height direction (direction Z) is obtained by adding the plate thickness t of the other spacers 24 and 25 to the outer dimension of the other outer shield case portion 22. It is defined as a length that substantially matches the inner dimension in the height direction (direction Z). The other side inner shield case portion 23 is formed such that the thickness of each side wall 23a, 23b, 23e is the same as the thickness of each side wall 13a, 13b, 13e of the one side inner shield case portion 13, and each side wall 23a, The interval 23b is defined to be the same as the interval between the side walls 13a and 13b.

  As shown in FIG. 3, the other side spacers 24 and 25 are non-magnetic and conductive metal plates (eg, bronze, copper, aluminum, etc.) having a uniform thickness t (the same thickness as the one side spacers 14 and 15) as an example. A plate made of a metal material is used to form a plane-symmetric shape. Specifically, the other side spacer 24 is connected to the side wall 23a of the other side inner shield case part 23 in contact with the first wall 24a, and is connected to the first wall 24a at a right angle so that the other side inner shield is disposed. The second wall 24b disposed in contact with the wall 23d on the other surface side of the case 23 and the front end of the main body case 2 at the other inner shield case 23 connected to the first wall 24a at a right angle. A third wall portion 24c disposed in contact with the wall portion 23e on the portion side is provided. Also, one elastic tongue piece 24d is formed as one example on the other side spacer 24 by cutting and raising a part of the other side spacer 24 (in this example, a part of the first wall portion 24a). . Specifically, the elastic tongue piece 24d is formed by raising a tongue-like portion surrounded by a U-shaped slit 24e formed in the first wall portion 24a. The shape of the slit 24e is arbitrary, and the shape of the slits 14e and 15e in the one-side sensor head 11 can also be applied. Alternatively, the elastic tongue piece can be formed by cutting and raising a part of the second wall portion 24b or the third wall portion 24c other than the first wall portion 24a.

The other side spacer 25 is connected at right angles to the first wall portion 25a and the first wall portion 25a disposed in contact with the side wall 23b of the other side inner shield case portion 23, so that the other side inner shield case portion 23 is connected. Are connected at right angles to the second wall portion 25b disposed in contact with the wall portion 23d on the other surface side and the first wall portion 25a on the other side inner shield case portion 23 on the distal end portion side of the main body case 2. A third wall portion 25c disposed in contact with the wall portion 23e is provided. The other side spacer 25 is formed with one elastic tongue piece 25d as an example by cutting and raising a part of the other side spacer 25 (a part of the first wall portion 25a as an example in this example). . Specifically, the elastic tongue piece 25d is formed by raising a tongue-like portion surrounded by a U-shaped slit 25e formed in the first wall portion 25a. The shape of the slit 24e is arbitrary, and the shape of the slits 14e and 15e in the one-side sensor head 11 can also be applied. Alternatively, the elastic tongue piece may be formed by cutting and raising a part of the second wall portion 25b or the third wall portion 25c other than the first wall portion 25a.
It is formed by being.

  The conductive connection member 26 is configured in the same manner as the conductive connection member 16, and is disposed between the other side core portion 27 and the other side inner shield case portion 23 as shown in FIG. 2.

  The other side core part 27 is comprised with the U-shaped core formed using magnetic materials, such as a ferrite. In this example, as an example, as shown in FIG. 2, three rectangular parallelepiped cores are combined to form one U-shaped core as the other-side core portion 27. The other side core part 27 can also be comprised. A detection coil 29 is disposed on the pair of leg portions 27 a of the other side core portion 27. The detection coil 29 and a hall element (not shown) (disposed close to the other core portion 27) are connected to the connector portion 30 via the wiring member W2, and the slide case is connected via the connector portion 30. 3 is connected to an electrical circuit (not shown) disposed in the interior. The other-side partition wall portion 28 is made of an electrically insulating material such as a synthetic resin material, and is positioned at the other-side core portion 27 and the other-side inner shield case portion 23 with respect to the other-side outer shield case portion 22. It has a function to define (position). Specifically, as shown in FIG. 3, the other-side partition wall 28 is formed in a bowl shape whose overall shape is a U-shaped cross section. Further, as shown in FIG. 2, the width of the other-side partition wall portion 28 is substantially the same as the gap between the pair of detection coils 29 disposed on each leg portion 27 a of the other-side core portion 27. Is stipulated.

  The other side outer shield case part 22, the other side inner shield case part 23, the pair of other side spacers 24 and 25, the conductive connection member 26, the other side core part 27, and the other side partition part 28 configured as described above are provided. First, the other side core portion 27 to which the detection coil 29 is mounted is fitted into the other side partition wall portion 28, and then the other side core portion on the inner surface (upper surface in FIG. 2) on the other side inner shield case portion 23 side. In the state where the conductive connection member 26 is disposed in a region facing the side 27, the other side partition wall portion 28 and the other side core portion 27 are accommodated in the other side inner shield case portion 23, and both ends of the other side partition wall portion 28 are accommodated. The portion is fitted into each cutout portion 23 c of the other-side inner shield case portion 23. Subsequently, the other-side spacers 24 and 25 are placed on the other-side inner shield case portion 23. In this state, the other-side inner shield case portion 23, the pair of other-side spacers 24 and 25, the conductive connection member 26, and the like. The side core portion 27, the detection coil 29, and the other side partition wall portion 28 are accommodated in the other side outer shield case portion 22, and both end portions of the other side partition wall portion 28 are formed in the respective notches 22 c of the other side outer shield case portion 22. Fit. At this time, the connector part 30 is also accommodated in the other outer shield case part 22 so that the connection pins arranged in the connector part 30 protrude from the insertion hole 22f. Thereby, the receiving position of the other side inner shield case part 23 with respect to the other side outer shield case part 22, the other side partition part 28 with respect to the other side outer shield case part 22, and the other by each end part of the other side partition part 28. The accommodation position in the other outer shield case portion 22 of the other core portion 27 fitted to the side partition wall portion 28 is defined. Finally, resin is injected into the other side outer shield case part 22, the other side inner shield case part 23 accommodated in the other side outer shield case part 22, the pair of other side spacers 24, 25, conductive connection The member 26, the other side core part 27, the other side partition wall part 28 and the connector part 30 are fixed to the other side outer shield case part 22. Thereby, the other side sensor head 21 is completed.

  In the other-side sensor head 21 in this state, as shown in FIG. 2, the other-side spacer 25 is in close contact with the inner surface of the other-side outer shield case portion 22 and is electrically connected to each other (not shown in the figure). The other-side spacer 24 is also electrically connected to the other-side outer shield case portion 22 in the same manner as the other-side spacer 25), and the other-side inner shield case portion 23 is in close contact with the other-side spacer 25 and is electrically connected. And the other side core portion 27 is electrically connected to the other side inner shield case portion 23 via the conductive connecting member 26. Further, in the other side sensor head 21, as in the case of the one side sensor head 11, the elastic tongue pieces 24 d and 25 d formed on the other side spacers 24 and 25 are pushed back against the elastic force. In this state, it is disposed between the other-side outer shield case portion 22 and the other-side inner shield case portion 23, so that electrical contact between the other-side outer shield case portion 22 and the other-side spacers 24 and 25 is achieved. , And a state in which electrical contact between the other side spacers 24, 25 and the other side inner shield case part 23 is sufficiently secured, that is, the other side core part 27, the other side inner shield case part 23, and the other side outer side. The shield case portion 22 is in a state of being in good electrical contact (good conduction state).

  Further, as shown in FIG. 2, in the other side sensor head 21, the side surfaces 22a and 22b of the other side outer shield case part 22 are arranged on the side surfaces facing the one side sensor head 11 (the notch part 22c in the figure is removed). And the other end walls (upper end surface in the figure) of the other pair of side walls 22d and 22e orthogonal to the side walls 22a and 22b are the inner shield case on the other side. End surfaces of the side walls 23a, 23b, 23e of the portion 23 on the side facing the one-side sensor head 11 (upper surface in the figure), and end surfaces of the leg portions 27a of the other-side core portion 27 (one-side sensor head 11) (The end face on the side opposite to the upper end face in the figure) and the same plane.

  As described above, in the clamp sensor 1, the one side sensor head 11 and the other side sensor head 21 of the sensor main body 4 are configured as described above. In a state in which the detected conductor 6 is disposed in the other side partition wall portion 28 of the side sensor head 21, the slide case 3 is slid toward the tip end side with respect to the main body case 2, and as shown in FIG. A state where the detected conductor 6 is clamped between the cases 2 and 3 (a state where the one-side sensor head 11 and the other-side sensor head 21 are arranged to face each other and the detected conductor 6 is inserted into the insertion hole 5. In the state where the one-side core portion 17 and the other-side core portion 27 constitute a magnetic closed circuit), as shown in FIG. 2, the side walls 12a, 12b, 12d, 12e of the one-side outer shield case portion 12 are provided. (The figure (The side wall 12a is not shown) and the corresponding side walls 22a, 22b, 22d, 22e in the other outer shield case 22 (note that the side wall 22a is not shown in the figure). And end surfaces (lower end surfaces) of the side walls 13a, 13b, 13e (the side walls 13a are not shown in the figure) of the inner shield case portion 13. And the corresponding end surfaces (upper end surfaces) of the corresponding side walls 23a, 23b, and 23e (the side wall 23a is not shown in the figure) in the other side inner shield case portion 23, and are in contact with each other. The end surface (lower end surface) of each leg portion 17a of the core portion 17 and the end surface (upper end surface) of each leg portion 27a of the other-side core portion 27 are in contact with and in contact with each other.

  In this example, as described above, in the other-side sensor head 21, the other-side spacer 24 having the elastic tongue piece 24d and the other-side spacer 25 having the elastic tongue piece 25d are used. The electrical connection state (conduction state) between the shield case portion 22 and the other side inner shield case portion 23 is maintained in a good state, and the other side core portion 27 and the other side inner shield case are provided by the conductive connection member 26. The electrical connection state (conduction state) with the unit 23 is maintained in a good state. Therefore, the potentials of the other side inner shield case part 23 and the other side core part 27 disposed in the other side outer shield case part 22 are well maintained at the same potential (ground potential) as the other side outer shield case part 22. Is done. In addition, thereby, the one-side outer shield case portion 12 in contact with the other-side outer shield case portion 22, the one-side inner shield case portion 13 in contact with the other-side inner shield case portion 23, and the one-side core in contact with the other-side core portion 27. Each potential of the portion 17 is also maintained at the same potential (ground potential) as the other-side outer shield case portion 22. Further, in this example, as described above, in the one-side sensor head 11, the one-side outer shield is formed by the one-side spacer 14 in which the elastic tongue piece 14d is formed and the one-side spacer 15 in which the elastic tongue piece 15d is formed. The electrical connection state (conduction state) between the case portion 12 and the one-side inner shield case portion 13 is maintained in a good state, and the one-side core portion 17 and the one-side inner shield case portion are formed by the conductive connection member 16. The electrical connection state (conduction state) with 13 is maintained in a good state.

  Therefore, according to the clamp sensor 1, in the one-side sensor head 11, the occurrence of poor contact between the one-side outer shield case portion 12 and the one-side inner shield case portion 13 is caused by the elastic tongue pieces 14d and 15d. The formed one-side spacers 14 and 15 can reliably avoid the occurrence of poor contact between the other-side outer shield case portion 22 and the other-side inner shield case portion 23 in the other-side sensor head 21. The other side spacers 24, 25 formed with the elastic tongues 24d, 25d can reliably avoid the other side inner shield case part 23, the one side outer shield case part 12, and the one side inner shield case part 13 from the other side. It is possible to reliably define the same ground potential as that of the shield case portion 22. For this reason, according to the clamp sensor 1, it is possible to always suppress external noise such as common mode noise to a desired level. As a result, the current detection accuracy of the detected conductor 6 can be further improved.

  In addition, according to the clamp sensor 1, the elastic tongue pieces 14d, 15d, 24d, and 25d are formed on the one-side spacers 14 and 15 and the other-side spacers 24 and 25, respectively. The electrical connection between the one-side outer shield case portion 12 and the one-side inner shield case portion 13 and between the other-side outer shield case portion 22 and the other-side inner shield case portion 23 is improved. Therefore, an increase in product cost can be suppressed to a necessary minimum while improving current detection accuracy.

  In addition, according to the clamp sensor 1, since the conductive connecting member 16 and the conductive connecting member 26 are provided, the one-side core portion 17 and the other-side core portion 27 are the same as the other-side outer shield case portion 22. The ground potential can be reliably defined. For this reason, the current detection accuracy of the conductor to be detected 6 can be further improved.

  In the clamp sensor 1 described above, the elastic tongue pieces 14d, 15d, 24d, and 25d are provided on the one-side spacers 14 and 15 on the one-side sensor head 11 side and the other-side spacers 24 and 25 on the other-side sensor head 21 side, respectively. The elastic tongue is applied to at least one of the four spacers 14 and 15 on the one side sensor head 11 side and the other side spacers 24 and 25 on the other side sensor head 21 side. A configuration in which a piece is formed may be employed. Further, the elastic tongues 14d and 15d are formed only on the one side spacers 14 and 15 and are not formed on the other side spacers 24 and 25. Conversely, the elastic tongues 24d and 24d are formed only on the other side spacers 24 and 25. It is also possible to adopt a configuration in which 25d is formed and not formed in the one-side spacers 14 and 15. Even in these configurations, the one-side outer shield case portion 12, the one-side inner shield case portion 13, the other-side outer shield case portion 22, and the other-side inner shield case portion 23 are compared with the configuration in which no elastic tongue is provided. Therefore, the current detection accuracy of the detected conductor 6 can be improved. When the conductive connecting member 16 and the conductive connecting member 26 are provided with only one of them, or when sufficient detection accuracy can be obtained by the configuration in which the elastic tongue is formed, the conductive connecting member 16 and A configuration in which both of the conductive connection members 26 are not provided can also be employed.

  As an example, the clamp sensor 1 having a configuration in which the elastic tongue pieces 14d and 15d are formed only on the one-side spacers 14 and 15 on the one-side sensor head 11 side, and both the conductive connecting members 16 and 26 are not provided, A clamp sensor (conventional clamp) having a configuration in which an elastic tongue piece is not formed on either one side spacer of the sensor head 11 or the other side spacer of the sensor head 21 and the conductive connecting members 16 and 26 are not provided. The frequency characteristics of the ratio of the common mode noise voltage to the probe output voltage (common mode noise voltage / probe output voltage) for the sensor) were measured experimentally. The result is shown in FIG. In addition, the thick line in the figure shows the frequency characteristic of the clamp sensor 1, and the thin line shows the frequency characteristic of the conventional clamp sensor. From this experimental result, it is confirmed that the frequency characteristic of the clamp sensor 1 is improved by about 30 dB in the range of 1 kHz to 300 kHz.

DESCRIPTION OF SYMBOLS 1 Clamp sensor 11 One side sensor head 12 One side outer shield case part 13 One side inner shield case part 14, 15 One side spacer 14d, 15d, 24d, 25d Elastic tongue piece 16, 26 Conductive connection member 17 One side core part 21 Other side sensor head 22 Other side outer shield case part 23 Other side inner shield case part 24, 25 Other side spacer 27 Other side core part

Claims (3)

In the state where the one side sensor head and the other side sensor head are arranged to face each other, the one side sensor head containing the one side core part and the other side sensor head containing the other side core part are disposed. A clamp sensor in which the part and the other side core part constitute a magnetic closed circuit and surround the conductor to be detected,
The one-side sensor head is housed in the box-shaped one-side outer shield case portion that is open on one side located on the side facing the other-side sensor head, the one-side outer shield case portion, and the one-side outer shield. One side inner shield case part that is formed in a box shape that opens in the same direction as the one side of the case part, and that accommodates the one side core part, and the one side outer shield case in the one side outer shield case part A one-side spacer that is disposed in a state interposed between a part and the one-side inner shield case part, and defines a housing position of the one-side inner shield case part with respect to the one-side outer shield case part,
The other-side sensor head is housed in the box-like other-side outer shield case portion that is open on one side located on the side facing the one-side sensor head, the other-side outer shield case portion, and the other-side outer shield. The other-side inner shield case portion that is formed in a box shape in which one surface side in the same direction as the one-surface side of the case portion is opened and accommodates the other-side core portion, and the other-side outer shield case in the other-side outer shield case portion Disposed on the other side inner shield case part, and having an other side spacer for defining the accommodation position of the other side inner shield case part with respect to the other side outer shield case part,
A clamp sensor in which at least one of the one side spacer and the other side spacer is formed with an elastic tongue piece by cutting and raising a part of the at least one spacer.   2. The clamp sensor according to claim 1, wherein each of the one side spacer and the other side spacer is formed with an elastic tongue piece by cutting and raising each of the spacers.   A conductive connecting member disposed between at least one of the one-side inner shield case part and the one-side core part and between the other-side inner shield case part and the other-side core part. The clamp sensor according to claim 1 or 2.

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