JP4569481B2 - Toroidal coil structure - Google Patents

Description

  The present invention functions as a current sensor for measuring a current flowing through a branch circuit of a domestic distribution board, particularly in a toroidal coil used for a current sensor, a choke coil for a digital circuit, a reactance for a signal filter, and a power transformer. The present invention relates to a toroidal coil structure.

  In general, a through-type current sensor is often used as a current sensor for non-contact measurement of the amount of alternating current supplied to a power transmission / transformation device, a home distribution board, or the like. Conventional examples of alternating current detection coils used in such a through-type current sensor are shown in FIGS. 21 and 22 (see Patent Document 1). In these figures, an alternating current detecting coil 200 includes a double-sided laminated substrate 202 (hereinafter referred to as a printed circuit board) having a circular substrate opening 201 and a coil body 203 disposed around the substrate opening 201. It is an air core coil provided. The material of the printed circuit board 202 is a glass-filled epoxy resin. The toroidal coil 203 includes a conductive portion of a conductive film that is radially printed around the substrate opening 201, and this conductive portion is connected via a connection portion that penetrates in the thickness direction of the printed circuit board 202, that is, in the axial direction of the coil body 203. By connecting in series, a toroidal coil is formed on the printed circuit board 202. The connection part is a through hole of a conductive film formed on the inner surface of the through hole of the printed circuit board 202. A coil wound around the printed circuit board 202 is wound at a constant pitch in two directions, and a winding coil 205 (hereinafter referred to as a leading coil) composed of a clockwise (direction of arrow 204) toroidal coil and counterclockwise ( The coil 205 and 207 are connected in series by connecting the end of the advance coil 205 and the start of the return coil 207. Has been. In FIG. 20, the lead coil 205 has a conductor portion formed on the surface of the printed circuit board 202 indicated by a thick solid line, and a conductor portion formed on the back surface is indicated by a thick broken line, and the return coil 207 is formed on the surface of the printed circuit board 202. The conductor portion formed is indicated by a double solid line, and the conductor portion formed on the back surface is indicated by a double broken line. On the front and back surfaces of the printed circuit board 202, the conductor portions of the coils 205 and 207 are alternately arranged at a constant pitch. In the advance coil 205, conductor portions having different lengths are alternately arranged at a constant pitch on the front surface and the back surface, and in the return coil 207, conductor portions having different lengths are alternately arranged at a constant pitch on the front surface and the back surface. ing. Further, in the lead coil 205, the pitch of each conductor portion is connected by a connecting portion (through hole) on the side away from the substrate opening 201, and in the return coil 207, each conductor portion is connected to the substrate opening 201. The pitch of each conductor part is connected by the connection part on the near side.

  In the current measurement using the AC current detecting coil 200, the conductor to be measured is passed through the board opening 201, and the magnetic flux generated by the current flowing through the conductor to be measured is indicated by the arrow 204 on the printed circuit board 202 of the coils 205 and 207. Alternatively, an induced voltage generated by passing through a cross-sectional area surrounded by the conductor portion when viewed from the direction of the arrow 206 is detected. On the other hand, when viewed in the axial direction of the toroidal coil main body 203, within the front area of the region surrounded by the conductor portions of the coils 205 and 207, there is a magnetic field other than the magnetic field to be detected (measured magnetic field) from the conductor to be measured. In some cases, a magnetic flux (referred to as an external magnetic field) generated from an electric wire other than the conductor to be measured also passes. This external magnetic field is unnecessary for the original current measurement. However, since both coils 205 and 207 formed in a circular shape are equivalently regarded as one large coil, if an unnecessary external magnetic field passes within the front area, the current caused by the external magnetic field is also reduced. It is detected at the same time. Since the detection current due to the external magnetic field becomes a measurement error, it is desirable that the influence be as small as possible. In order to suppress this measurement error, it is necessary to equalize the front areas of the coils 205 and 207 whose winding directions are opposite to each other with respect to the external magnetic field to cancel out the unnecessary detection current.

  However, in the conventional current sensor, when the coils 205 and 207 are viewed in the axial direction, the front area of the advance coil 205 is larger than the front area of the return coil 207, and the front areas are different. Therefore, the detected amount of the induced voltage due to the external magnetic field differs between the coils 205 and 207, and they are not completely canceled out, so that it is difficult to suppress measurement errors.

  Further, in the above current measurement, in order to increase the measurement sensitivity, it is necessary to increase the induced voltage from the measurement magnetic field that contributes to the measurement of both the coils 205 and 207. In both the coils 205 and 207, the surface perpendicular to the substrate is required. It is desirable that the cross-sectional areas of the cross-sectional areas surrounded by the conductor portions are equal when cross-sectioned and the induced voltage is generated uniformly. However, the cross-sectional areas of the coils 205 and 207 are different for each winding pitch, and therefore there is a problem that measurement sensitivity is deteriorated.

  Furthermore, if the cross-sectional areas of the two coils 205 and 207 are different, the amount of magnetic flux of the external magnetic field that passes through the cross-sectional area is different. The amount of external magnetic field that is generated is reduced, further increasing the measurement error. In particular, the difference in the detection of the external magnetic field due to the difference in the cross-sectional area becomes larger as the distance between the current sensor and the electric wire that generates the external magnetic field that does not need to be detected becomes shorter. That is, when the electric wire that generates an external magnetic field that does not need to be detected is near the detection coil, the magnetic flux of the diagonal component is relatively larger than when it is far away. Due to the difference, a difference occurs in the detection of the external magnetic field, and the canceling action of the unnecessary magnetic field is reduced.

  As described above, in the detection coil 200, even when the front and return coils have the same front area, if the cross-sectional areas of the coils are different, they are canceled in the vicinity of the electric wire that generates an external magnetic field that does not require detection. As a result, the amount of external magnetic field decreases, and the measurement error increases. Therefore, in order to strictly reduce the influence of the external magnetic field, it is necessary that the front areas of the advance coil and the return coil are substantially the same, and the cross-sectional areas of the coils in the cross-sectional direction are also substantially the same.

  However, in the toroidal coil used for the AC current detecting coil 200 as described above, since the coil is formed on the double-sided printed board, the shape of the coil is limited due to the structure of the double-sided printed board. It was difficult to design a toroidal coil that is substantially the same in cross-sectional area in the direction. In addition, the coil manufacturing process using a double-sided printed circuit board requires etching and through-hole processing, which complicates the manufacturing process and connects the conductive foil patterns on the printed circuit board with through-holes. However, there was a risk of cracks due to environmental changes, and there was a problem in reliability. In addition, it is difficult to increase the thickness of the conductor foil pattern due to the etching process. For this reason, the resistance value of conductor foil became large and there were many conductor losses of a coil. Moreover, in the toroidal coil of the printed circuit board, since the air core includes a dielectric, coil loss due to dielectric loss has occurred.

In addition, as an alternating current detection coil, a coil main body is arranged around the opening of the substrate on an insulating substrate, and has a winding coil and a winding coil formed in a coil shape with a conductive film, and these are connected in series. An air-core coil is known (see Patent Document 2). However, also in this conventional example, the toroidal coil is formed of a printed circuit board. In this air-core coil, when viewed from the axial direction of the coil, the winding advance coil forms a sawtooth pattern, and the rewinding coil Has a triangular shape, and the two coils have different shapes. For this reason, since the area surrounded by the two coils is not the same, there is a difference in the amount of magnetic flux of the external magnetic field passing through both coils, and there is a problem that the influence of the external magnetic field cannot be sufficiently eliminated as described above. .
Japanese Patent Laid-Open No. 06-176947 Japanese Patent Laid-Open No. 2004-87619

  The present invention has been made in order to solve the above-described problem, and the coils are three-dimensionally formed by punching and bending a thin metal plate so that the coils are close to each other so that they can be easily overlapped. An object of the present invention is to provide a toroidal coil that is easy to manufacture, has high coil accuracy and reliability, has high current detection sensitivity, and has little measurement error.

The invention of claim 1 in order to achieve the above object, to form a continuous conductive pattern circumferentially spiral shape by punching a metal sheet, the pattern extending radially adjacent the conductive pattern The coil body is alternately bent in the thickness direction to form a coil body, and the coil body has radial lines formed above and below in the thickness direction by a pattern formed in a step difference. And Rogowski coil in which the two coils are arranged in close proximity so that their radial lines overlap each other in the thickness direction, and one end and the other end of the coils are connected. Structure.

The invention of claim 2 is the Rogowski coil structure of claim 1, comprising two said coil body, by placing upside down one with respect to the other, both directions coil rewind winding leading direction A coil is formed, these two coils are arranged close to each other, and one end and the other start are connected.

The invention according to claim 3, in Rogowski coil structure according to claim 1 or claim 2, in punching condition of the sheet metal, the bending pattern provided on a part of the pattern extending to the radially stepped by the bending pattern A bent portion is formed.

  According to the first aspect of the present invention, since the coil body can be formed by a process only of punching and bending, the coil can be easily manufactured and the toroidal coil can be accurately formed in the same shape three-dimensionally. Thereby, it becomes possible to obtain a highly accurate AC detection sensor by combining the toroidal coils. Further, compared to a toroidal coil using a printed circuit board, a continuous coil body can be formed from a single metal thin plate without joints or through-hole connections, so that the reliability of the coil can be improved. Further, the punching and bending processes can increase the thickness of the coil conductor as compared with the toroidal coil of the printed circuit board that requires etching, so that the conductor loss of the coil can be reduced. Furthermore, since the coil structure is made three-dimensional, the inside of the coil air core can be made a space, so that the dielectric loss of the coil is reduced as compared with the conventional printed circuit board coil using the air core as a dielectric. be able to.

In addition, since the toroidal coils of the coil in the rewinding direction (referred to as the rewinding coil) and the coil in the rewinding direction (referred to as the rewinding coil) can be accurately stacked in the vicinity, both coils should be arranged at substantially the same position. It is possible to arrange the coil pitches so as to overlap. Therefore, in the alternating current sensor formed by such a toroidal coil, the coil cross-sectional areas in the axial direction and the circumferential direction can be approximately equal with high accuracy, and the distance from the external magnetic field source in both coils is equal, so detection is not necessary. Therefore, the induced electromotive currents of the two coils are substantially equal to the external magnetic field, and the cancellation error of the induced electromotive currents can be minimized, and the current measurement accuracy can be improved.

According to the invention of claim 2 , since the Rogowski coil structure of the winding advance coil and the rewinding coil can be formed with the coil pattern having the same shape, the shape of the coil pattern for the toroidal coil may be one type, and the punching die This reduces the production cost.

According to the invention of claim 3 , since the bending load in the thickness direction of the coil body can be reduced at the time of bending the radial pattern in the thickness direction, it is possible to form a bent portion that is a stable and highly reliable step. Moreover, since the bending length can be increased, the circumferential cross-sectional area of the coil body can be increased, and the current detection sensitivity of the coil can be increased.

  The toroidal coil structure according to the first embodiment of the present invention will be described below with reference to FIGS. 1, 2 and 3, the toroidal coil 1 (coil body) of the present embodiment is formed by a conductor pattern 2 which is formed in a spiral shape by punching a thin metal plate and is continuous in the circumferential direction. This conductor pattern 2 is formed in a donut-shaped circular shape by a spiral shape continuing on the circumference, and has a circular opening 4 on the inner side, and the center of the pattern is X. The conductor pattern 2 includes radial lines 3 formed in a radial pattern, and connecting portions 51 and 52 that alternately connect both ends of the radial lines 3 adjacent to each other on the outer peripheral side and the inner peripheral side of the donut. And coil lead-out terminals 61 and 62 for taking out a detection current signal. Further, the radial line 3 includes a linear radial line 31 and a bent radial line 32 having a bent portion 32x to be bent, and the adjacent line intervals of the radial line 3 are all formed substantially equal. . The continuous radial line pattern by these radial lines 31 and 32 and the connection parts 51 and 52 is arrange | positioned on the circumference at equal pitch intervals, and becomes axially symmetric with respect to a central axis.

  As shown in FIGS. 2 (a) and 2 (b), the radial line 32 is formed with an S-shape at a part of substantially both ends of the radial line pattern when the thin metal plate is punched, as shown in FIGS. Each of the bending patterns 32s is formed. As shown in FIG. 3A, when the bending pattern 32s is bent, when a force is applied to a radial line before bending indicated by a dotted line in the thickness direction indicated by an arrow, an S-shaped curve of the pattern 32s is formed in the arrow direction. The portion extends in a straight line and becomes long, and a radial line 32 is formed which is different from the adjacent radial line 31. As shown in FIG. 3B, the bent portion 32x has a substantially trapezoidal shape connecting the side sides 32p and 32q and the bottom side 32r. As shown in part B surrounded by the dotted line in FIG. 3B, one line of the radial line 31 and one line of the radial line 32 provided with the bent part 32x are substantially trapezoidal one-turn coils. (Coil T) is formed. A plurality of the coils T are connected to each other and formed in a shape that makes a circle. Thereby, the toroidal coil 1 is formed by forming the three-dimensional coil continuously in a circumferential shape from one metal thin plate. Also, as shown in FIG. 3C, the circumferential cross section of the toroidal coil 1 is substantially a base surrounded by the sides 32 p and 32 q of the bent portion 32 x of the radial line 32, the bottom 32 r and the radial line 31. The trapezoidal area is the cross-sectional area Sa of the toroidal coil 1. In the current detection using the toroidal coil 1, a conductor to be measured through which the current flows is passed through the opening 4, and a magnetic flux (referred to as a measurement magnetic field) caused by this current passes through the cross-sectional area of the toroidal coil 1. Detect voltage.

  As shown in FIGS. 4 (a) and 4 (b), the toroidal coil 1 has the same length and spacing between adjacent radial lines 3 constituting the coil. It becomes substantially symmetrical with respect to the central axis passing through the center X of the toroidal coil 1. The same coil T starts from the coil T1 at the start of the coil connected to the coil lead-out terminal 61, and the coil T is continuously connected around the circumference in the circumferential direction, and is the terminal coil adjacent to the coil T1 at the start. By returning to Tn, the toroidal coil 1 is formed. Then, a detection current based on an electromotive current generated by a current flowing through the electric wire passing through the center X of the toroidal coil 1 is taken out from both terminals of the coil lead terminal 61 and the coil lead terminal 62 connected to the terminal coil Tn. Further, in the planar pattern viewed from the central axis of the toroidal coil 1, all the coils T formed by the adjacent radial lines 3 have substantially the same planar area Sb (shaded portion). Therefore, the same detection current output is obtained in each coil T with respect to the magnetic field coming from the central axis of the toroidal coil 1.

  With the above configuration, the toroidal coil 1 can be formed by a process of only punching and bending, so that the coil can be easily manufactured and the toroidal coil 1 can be accurately formed in the same shape three-dimensionally. Thereby, it becomes possible to obtain a highly accurate AC detection sensor by combining the toroidal coils 1. In addition, since the continuous toroidal coil 1 can be formed from a single thin metal plate having no joints or through-hole connection portions, the reliability of the coil can be improved as compared with a toroidal coil using a printed circuit board. . Moreover, since the thickness of a coil conductor can be increased compared with the toroidal coil of the printed circuit board which requires an etching and a bending process, the conductor loss of a coil can be reduced. Furthermore, the coil structure is made three-dimensional, so that the inside of the coil air core can be made into a space, so that the dielectric loss of the coil can be reduced as compared with the conventional printed circuit board coil using the air core as a dielectric. it can.

  Next, an alternating current detection coil 100 having a toroidal coil structure according to a second embodiment of the present invention will be described with reference to FIGS. The alternating current detection coil 100 of this embodiment includes two types of toroidal coils 1 in the winding direction (hereinafter referred to as winding coil 1) and toroidal coils 10 in the rewinding direction (hereinafter referred to as rewinding coil 10). An alternating current detection coil 100 is formed by arranging a toroidal coil close to each other and connecting one end to the other end. The winding advance coil 1 and the winding return coil 10 basically have the same structure as the toroidal coil 1 of the first embodiment, and the winding directions of the coils 1 and 10 are opposite to each other. It is formed.

  The coil 100 for detecting an alternating current of the present embodiment is a winding advance coil 1 that advances in a winding advance direction by a toroidal coil formed by punching a thin metal plate and bending a spiral conductive pattern 2a in the circumferential direction. And a rewinding coil 10 that advances in a rewinding direction by a toroidal coil formed by bending a metal pattern that is punched out and bent in a spiral shape in the circumferential direction. Then, as shown in FIG. 6, the winding advance coil 1 and the rewinding coil 10 are arranged close to each other in the thickness direction, and are electrically insulated and positioned by an insulator 7 such as a resin. In the current detection using the winding advance coil 1 and the rewinding coil 10, the conductor to be measured through which the current flows is passed through the opening 4, and the magnetic flux of the magnetic field (referred to as a measurement magnetic field) caused by this current is wound up. An induced voltage generated by passing through the cross-sectional area of the return coil 10 is detected.

  As shown in FIGS. 7A and 7B, each of the conductor patterns 2a and 2b is formed into a donut-shaped circular shape by continuing a spiral shape on the circumference, and has a circular opening inside. 4 and X is the center of the pattern. The conductor patterns 2a and 2b include radial connecting lines 51 formed radially, and connecting portions 51 that alternately connect both ends of the radial lines 3 that are adjacent to each other on the outer peripheral side and the inner peripheral side of the donut. 52, 53 and 54, and coil lead terminals 61, 62 and 63, 64 for taking out a detected current signal, respectively.

  In the radial line 3, linear radial lines 31 and bent radial lines 32 are alternately formed, and each radial line 32 has an S-shaped pattern 32s for bending near both ends thereof. Further, the pattern shapes of the conductor patterns 2a and 2b are line symmetric shapes having the same shape when the left and right are reversed with respect to the diameter lines Y1 and Y2 passing between the coil lead terminals 61 and 62 and 63 and 64 of each pattern. Make. That is, in both patterns 2a and 2b, the position of the bent radial line 32 where the S-shaped pattern 32s exists as viewed from the diameter lines Y1 and Y2 is symmetrical.

  As shown in FIGS. 8A and 8B, the symmetrical patterns 2a and 2b are formed by winding a winding coil 1 and a rewinding coil 10 made of a three-dimensional toroidal coil in the same manner as in the embodiment. It becomes. 8A and 8B, the winding advance coil 1 has a coil lead terminal 61 as a coil lead terminal 61. The coil lead terminal 61 is a coil lead coil 61. As shown in FIG. Are first connected to the bent radial line 32, and then connected to the adjacent linear radial line 31. As a result, in the winding advance coil 1, each coil T rotates right within the cross section, and the coil as a whole advances counterclockwise. On the other hand, the rewinding coil 10 has a coil lead terminal 63 at the start end of the coil, and this coil lead terminal 63 is first connected to the linear radial line 32 among the radial lines 3 of the rewinding coil 10 and then adjacent. It is connected to a bent radial line 32. As a result, in the rewinding coil 10, each coil T rotates counterclockwise within the cross section, proceeds as a whole in the clockwise direction, and rewinds in the reverse direction with respect to the rewinding coil 1.

  Next, the configuration of the alternating current detection coil 100 in which the winding advance coil 1 and the rewinding coil 10 are arranged close to each other and connected will be described with reference to FIGS. 9 (a) and 9 (b). In this alternating current detection coil 100, the winding coil 1 and the rewinding coil 10 both have a radial line 31 on the upper side in the thickness direction and a radial line 32 on the lower side in the circumferential cross section. They are arranged in the direction and arranged with a distance d in the thickness direction. The coils 1 and 10 are brought close to each other as long as their electrical insulation can be maintained, and the gap d is insulated and positioned by an insulator 7 such as a resin.

  Further, since the patterns 2a and 2b are symmetric, in the connection portions 51 and 53 on the outer peripheral side of the winding advance coil 1 and the rewinding coil 10, a linear radial line 31 and a bent radial line that are connected to each other connection portion. The position 32 is reversed left and right. Here, when the coils 1 and 10 are overlapped close to each other, when viewed in a plan view, the coil lead terminals 61 and 63 (or 62 and 64) are overlapped to be bent and connected to the coil lead terminal 61. Since the radial line 32 rides on and overlaps the linear radial line 31 connected to the coil lead-out terminal 63, the distance between the coils 1 and 10 when they are overlapped increases as the height of these coil cross sections. End up. For this reason, the coils are connected to each other while being shifted from each other by the interval between the adjacent radial lines 3 (the coil pitch of the one-turn coil) when viewed in plan. Accordingly, the radial lines 31 and the radial lines 32 are arranged so as to overlap each other between the coils 1 and 10, and the distance between the coils 1 and 10 can be reduced. An alternating current detecting coil 100 is formed. Further, the cross-sectional areas of the coils 1 and 10 in the circumferential direction are the areas surrounded by the radial lines 31 and 32 of the coils 1 and 10, respectively, and the conductor patterns 2a and 2b have the same shape. Both have the same area Sa.

  FIGS. 10A and 10B show a plan view of an alternating current detection coil 100 formed by stacking the winding advance coil 1 and the rewinding coil 10. In this alternating current detection coil 100, a coil T surrounded by the radial line 3 and the connection portions 51 and 52 or the connection portions 53 and 54 is formed for each of the coils 1 and 10 from the coil T1 to the coil Tn over the circumference. Is done. The coils 1 and 10 are connected in series by the connection between the coil lead terminals 62 and 63, and the induced voltage of the coil output is taken out from the coil lead terminals 61 and 64. In this alternating current detection coil 100, the lengths and intervals of the adjacent radial lines 3 are all equal, so that when viewed from the front of this alternating current detection coil 100, the respective planar areas of the winding advance coil 1 and the rewinding coil 10 are Will be equal. Thereby, since both the coils 1 and 10 have the same plane area Sb, the unnecessary external magnetic field which comes from the center axis | shaft of these both coils 1 and 10 can be canceled accurately.

  Next, a manufacturing process of the alternating current detection coil 100 using the winding advance coil 1 and the rewinding coil 10 will be described with reference to FIG. This manufacturing process is performed using a lead frame method and a resin mold. As shown in FIG. 11, in this manufacturing process, the winding advance coil 1 and the rewinding coil 10 are formed by first forming the conductor patterns 2a and 2b in the metal thin plate by the metal thin plate punching process (S1). Subsequently, the lead frame type winding advance coil 1 and rewinding coil 10 are formed in the metal thin plate by a bending process (S2). Then, the winding advance coil 1 and the rewinding coil 10 are overlapped with the thickness direction aligned with an insulation interval (S3), and then the overlapped coils 1, 10 are integrally molded with a resin mold or the like. (S4). On the other hand, a coil mounting board 41 on which the alternating current detection coil 100 is mounted is prepared separately, and a coil insertion hole 41a is provided in a part of the board 41 so as to be fitted to the coil (S5). . The molded alternating current detection coil 100 is separated from the thin metal plate (S6) and mounted on the coil mounting board 41, and the coil lead terminals 61 to 64 are signal processing circuits on the coil mounting board 41. 41b is completed as a current sensor (S7). Thereby, the AC current detecting coil 100 without a package can be directly mounted on the coil mounting substrate 41 from the lead frame processing, and the small and low cost AC current detecting coil 100 which does not require a package can be obtained by a simple process. It can be easily realized.

  Thus, according to the present embodiment, the coil 1 and the rewind coil 10 can be formed symmetrically and three-dimensionally with a toroidal coil by punching and bending a thin metal plate. It can arrange | position close to the same position and it can arrange | position so that a coil pitch may overlap. Therefore, in the alternating current detection coil 100 formed by the winding advance coil 1 and the rewinding coil 10, the coil cross-sectional areas in the axial direction and the circumferential direction can be made almost equal with high accuracy. Since the winding pitch can be formed with high accuracy, both the planar area from the front side of the coils 1 and 10 and the cross-sectional area in the circumferential direction can be made extremely equal. In particular, since the two coils 1 and 10 are arranged at substantially the same position, the distances from the external magnetic field generation sources in both the coils 1 and 10 become equal. As a result, the cancellation error of the induced voltage can be minimized, and the current measurement accuracy can be increased.

  Next, referring to FIGS. 12A and 12B and FIGS. 13A, 13B, 13C, and 13C for an alternating current detection coil having a toroidal coil structure according to the third embodiment of the present invention. I will explain. An alternating current detection coil 100 according to this embodiment is obtained by integrating the winding advance coil 1 and the rewinding coil 10 in the second embodiment in a case 70. In these figures, an alternating current detection coil 100 is an insulator ring that electrically insulates between the winding advance coil 1 and the rewinding coil 10 and the connection portions 52 and 54 on the inner peripheral side of these coils 1 and 10. 9a, and a case 70 made of an insulating material that accommodates both the coils 1 and 10 close to each other while maintaining insulation. In this case 70, as shown in FIG. 12A, the rewinding coil 10, the insulator ring 9a, and the winding advance coil 1 are inserted in this order. In the current detection of the alternating current detection coil 100 using these coils 1 and 10, the conductor to be measured through which the current flows is passed through the opening 4, and the magnetic flux of the magnetic field due to this current is a cross-sectional area of both the coils 1 and 10. The induced voltage generated by passing through is detected.

  The case 70 includes a donut-shaped cylindrical casing 71 having a circular cavity 72 therein, and the casing 71 includes a bottom surface 73, a circular outer peripheral wall 74, and an inner peripheral wall 75. 74 and 77, circular support bases 76 and 77 having the same height for holding the coils 1 and 10 are formed in the housing 71 along the inner peripheral wall 75. These support bases 76 and 77 are configured so as to support only the outer peripheral side and inner peripheral side connection portions 51 to 54 of the winding advance coil 1 and the rewinding coil 10 and not the radial line 3 portions. Yes. In addition, between these support bases 76 and 77, a substantially rectangular parallelepiped insulating support base 78 that supports an intermediate portion of the radial line 3 of the rewinding coil 10 is provided radially. Further, a support portion 76a higher than the thickness of the coil conductor is provided on the upper portion of the support base 76, and the winding advance coil 1 and the rewinding coil on the outer peripheral side are supported by supporting the winding advance coil 1 on the support portion 76a. 10 insulation is maintained. The space interval L1 between the adjacent support portions 76a and the outer dimension width L2 between the two adjacent radial lines 3 of the connection portion 53 of the winding advance coil 10 are substantially equal to each other between the adjacent support portions 76a. The connecting portion 53 is fitted and the rewinding coil 10 is fixed. Further, the circumferential width L3 of the support portion 76a and the inner dimension width L4 on the outer peripheral side between the radial lines 3 to which the connection portion 51 is connected are substantially equal to each other, and the inner dimension width L4 is provided on the support portion 76a. The protruding portion 76b is substantially fitted to fix the winding advance coil 1.

In this AC current detection coil 100, the winding coil 1, the rewinding coil 10, and the insulator ring 9a are sequentially inserted into the case 70, and the rewinding coil 10 is connected to the outer peripheral side and inner peripheral side connection portions 53, In FIG. 54, the connection portions 53 on the outer peripheral side are respectively held on the support bases 76 and 77, and are substantially fitted into and held between the adjacent support portions 76a on the support base 76. Next, a disc-shaped insulator ring that has an inner diameter larger than the outer diameter of the inner peripheral wall 75 and covers only the vicinity of the connection section 54 that has little influence on magnetic field detection is provided on the held inner peripheral connection section 54. 9a is mounted. Further, the coil 1 is mounted on the insulator ring 9a, and the inner peripheral connection portion 52 is supported by the insulator ring 9a while maintaining insulation. Further, the outer peripheral connection portion 51 is attached to a support portion 76a on the support base 76, and is substantially fitted and held by a protrusion 76b provided on the support portion 76a.

  Further, as shown in FIG. 13C, the circumferential cross-sectional areas of the winding advance coil 1 and the rewinding coil 10 are the areas surrounded by the radial lines 31 and 32 in both the coils 1 and 10, respectively. Since the corresponding radial lines are the same, the same cross-sectional area (Sa) is obtained.

  Next, a manufacturing process of the alternating current detection coil 100 using the winding advance coil 1 and the rewinding coil 10 will be described with reference to FIG. This manufacturing process is performed using a lead frame method and a resin package. In this manufacturing process, the winding advance coil 1 and the rewinding coil 10 are formed by first punching a thin metal plate in the punching step 1 (S1), and the punched conductor patterns 2a and 2b are separated from the thin metal plate. In addition, the lead frame type winding advance coil 1 and the rewinding coil 10 are formed by the bending step (S2). These coils 1 and 10 are inserted into a coil case 70 separately prepared in the order of the rewinding coil 10, the insulator ring 9a, and the winding advance coil 1 and filled with resin (S4). Thereafter, a connection process between the coils 1 and 10 is performed (S5), the coil is mounted on the coil mounting board 41, and the coil lead-out terminal is connected to the signal processing circuit 41b on the board 41 to form the AC current detecting coil 100. Completed (S6). As a result, the winding advance coil 1 and the rewinding coil 10 can be easily formed from a thin metal plate by a lead frame method and mounted in the package, so that the coils 1 and 10 can be reliably detected with little misalignment. The coil 100 can be easily realized by a simple process.

  Thus, according to the alternating current detection coil 100 using the winding advance coil 1 and the rewinding coil 10 of the present embodiment, both the coils 1 and 10 can be arranged close to each other in the thickness direction with high accuracy. The current detection error can be reduced by canceling unnecessary external magnetic field, and it can be fixed and held in the case while maintaining insulation, so it is high performance, compact, easy to handle and reliable. High AC current detecting coil 100 can be formed.

  Next, an alternating current detection coil having a toroidal coil structure according to a fourth embodiment of the present invention will be described with reference to FIGS. 15 (a) to 15 (d) and FIG. The alternating current detection coil 100 of the present embodiment includes two toroidal coils 1 (see FIG. 1) (coil body) having the same shape, and is arranged in the reverse direction with respect to the other to be wound in the winding advance direction. A traveling toroidal coil 1 (hereinafter referred to as “rewinding coil 1”) and a toroidal coil 10 (hereinafter referred to as “rewinding coil 10”) to be rewound in the rewinding direction are formed. And the other end. The winding advance coil 1 and the rewinding coil 10 basically have the same structure as the toroidal coil 1 of the first embodiment. It is formed so that the directions are opposite to each other.

  The alternating current detection coil 100 of this embodiment is a toroidal coil 1 similar to that of the first embodiment, which is formed by punching a thin metal plate and bending a spiral conductive pattern 2 in the circumferential direction. As shown in FIGS. 15 (b) and 15 (c), one toroidal coil 1 is wound into a coil 1 and the other toroidal coil 1 is turned upside down, as shown in FIGS. 15 (b) and 15 (c). And the coils 1 and 10 are overlapped and arranged close to each other. Of the coil lead terminals 61 and 62 and the coil lead terminals 63 and 64 of both the coils 1 and 10, a coil lead terminal 62 at the end of the winding coil 1 and a coil lead terminal 63 at the start of the rewind coil 10 are provided. The coils 1 and 10 are connected in series, and the detected current is taken out from the coil lead terminals 61 and 64.

  As shown in FIG. 16, the linear radial line 31 of the winding advance coil 1 and the bent radial line 32 of the rewinding coil 10 are close to each other by arranging the two identical coils inverted as described above. On the contrary, the bent radial line 32 of the winding coil 1 and the linear radial line 31 of the rewinding coil 10 are arranged so as to overlap each other. The two coils 1 and 10 are positioned by overlapping each other in the thickness direction and electrically insulating with an insulator such as resin. With such a configuration, as shown in FIG. 16B, the circumferential cross-sectional area Sc (shaded portion) formed by the radial lines 31 and 32 in the rewinding coil 10 with the winding advance coil 1 is substantially the same. Will be equal. As a result, in current detection using both the coils 1 and 10, the conductor to be measured through which the current flows is passed through the opening 4, and the magnetic flux of the magnetic field due to this current is generated by passing through the cross-sectional areas of the coils 1 and 10. The induced voltage is detected with high accuracy.

  FIG. 17 shows a plan view of the alternating current detection coil 100 formed by stacking the winding advance coil 1 and the rewinding coil 10. In this alternating current detection coil 100, a coil T surrounded by the radial line 3 and the connection portions 51 and 52 or the connection portions 53 and 54 is formed for each of the coils 1 and 10 from the coil T1 to the coil Tn over the circumference. Is done. The coils 1 and 10 are connected in series by the connection between the coil lead terminals 62 and 63, and the induced voltage of the coil output is taken out from the coil lead terminals 61 and 64. In this alternating current detection coil 100, the lengths and intervals of the adjacent radial lines 3 are all equal, so that when viewed from the front of this alternating current detection coil 100, the respective planar areas of the winding advance coil 1 and the rewinding coil 10 are Will be equal. Thereby, since both the coils 1 and 10 have the same plane area Sd, the unnecessary external magnetic field which comes from on the central axis of these both coils 1 and 10 can be canceled accurately.

  Thus, according to the alternating current detection coil 100 of the present embodiment, the winding coil 1 and the rewinding coil 10 can be formed with the same shape coil pattern, so that the shape of the coil pattern for the toroidal coil is one kind. Well, there are few punching dies, and the production cost can be reduced. Further, in the winding advance coil 1 and the rewinding coil 10, since the planar area in the front direction and the sectional area in the circumferential direction are equal, an unnecessary external magnetic field can be canceled and detection errors can be reduced.

  Next, an alternating current detection coil having a toroidal coil structure according to a fifth embodiment of the present invention will be described with reference to FIGS. 18 (a), (b), FIG. 19, FIG. 20 (a), and (b). explain. An alternating current detection coil 100 using a toroidal coil in the present embodiment is obtained by integrating the winding advance coil 1 and the rewinding coil 10 in the fourth embodiment in a case 70. In these figures, an alternating current detecting coil 100 includes an insulator ring 9b that electrically insulates the connection portions 52 and 54 on the inner peripheral side of both the winding coil 1 and the rewinding coil 10; And a case 70 made of an insulating material that houses the coils 1 and 10 close to each other while maintaining insulation. As shown in FIG. 18A, the rewinding coil 10, the insulator ring 9 b, and the winding advance coil 1 are attached to the case 70 in order, and the end of the winding advance coil 1 and the rewinding coil are mounted. 10 start ends are connected in series. In current detection using both the coils 1, 10, the conductor to be measured through which the current flows is passed through the opening 4, and the magnetic flux of the magnetic field caused by this current advances and passes through the cross-sectional areas of the coil 1 and the rewinding coil 10. The induced voltage is detected.

  As shown in FIG. 18B, the case 70 includes a housing 71 having a donut-shaped cylindrical shape having a circular cavity 72 therein. The casing 71 includes a bottom surface 73, a circular outer peripheral wall 74, and a circular outer peripheral wall 74. A substantially rectangular support base 79 is formed radially at equal intervals along the inner side of the outer peripheral wall 74 to hold the connection portions 51 and 53 on the outer peripheral side of the coils 1 and 10. ing. The support 79 supports only the connection portions 51 and 53 on the outer peripheral side of the winding advance coil 1 and the rewinding coil 10 and does not support the other radial line 3 portions in the radial direction of the case 70. The length is limited. Further, as shown in FIG. 19, the distance L1 between the adjacent support bases 79 is the outer dimension of the distance between the adjacent radial lines 3 connected by the connecting portion 53 on the outer peripheral side of the rewinding coil 10 in the gap. The width (corresponding to the distance L2 between the adjacent radial lines 3 connected by the connecting portion 51 of the winding coil 1) is made substantially equal to each other, and the connecting portion 53 is formed to be substantially fitted. Thereby, the rewinding coil 10 is fixed in close contact with the bottom surface 73 side in the housing 71. On the other hand, on the upper portion of the support base 79, support portions 79 a are provided radially at equal intervals corresponding to the radial lines 3 in order to hold the connection portion 51 on the outer peripheral side of the winding advance coil 1. The circumferential width L3 of the support portion 79a is substantially equal to the inner dimension width L4 between the adjacent radial lines 3 connected by the connection portion 51, and the support portion 79a is substantially fitted into the inner dimension width L4. It is formed to match. Thereby, the winding advance coil 1 is hold | maintained by the support part 79a.

FIGS. 20A and 20B show the alternating current detection coil 100 of the present embodiment in which the case 70 accommodates the winding advance coil 1, the rewinding coil 10, and the insulator ring 9b. In the case 70, first, the rewinding coil 10 is inserted, and the rewinding coil 10 is mounted by fitting the connecting portion 53 on the outer peripheral side between the adjacent support bases 79. A cylindrical insulator ring 9b having an inner periphery larger than the inner peripheral wall 75 and covering only the vicinity of the connection portion 54 having little influence on the magnetic field detection is mounted on the connection portion 54 on the inner periphery side. The height d1 of the insulator ring 9b is provided such that the height (d1 + dp) obtained by adding the coil conductor plate thickness dp to the d1 is substantially equal to the height d3 of the one support 79. The height d3 is larger than the outer dimension distance d2 between the radial line 31 and the radial line 32 in the cross section in the thickness direction, and the linear radial line 31 and the bent shape of the winding advance coil 1 and the rewinding coil 10 are bent. The radial lines 32 are not in contact with each other and are electrically insulated. Thereby, each cross section of the circumferential direction of the winding advance coil 1 and the rewinding coil 10 becomes line-symmetrical up and down, and the magnitude | size of each cross-sectional area can be made equal. Therefore, the detection magnetic field flows smoothly in the coil, the current detection sensitivity is improved, and the canceling action against the unnecessary external magnetic field can be enhanced.

  With the above configuration, according to the alternating current detection coil 100 of the present embodiment, the rewinding coil 1 and the rewinding coil 10 having the same shape and the reversed coil patterns are connected to each other at both ends of both the coils 1, 10. Insulating properties can be reliably maintained while being supported only by the connecting portions (51 to 52) and bringing the coils 1 and 10 close to each other. Therefore, the radial line 3 for detecting the magnetic field has a simpler structure because there is no support for supporting the intermediate part of the radial line compared to the third embodiment. Since the magnetic field is not disturbed, the magnetic field can be detected smoothly and the current detection sensitivity is improved.

  According to the configuration of the alternating current detection coil 100 having the toroidal coil structure according to each of the embodiments described above, the coil can be easily manufactured by the toroidal coil manufacturing process by punching and bending, and the winding coil 1 and the rewinding coil are made. 10 can be accurately formed in the same shape three-dimensionally. Thereby, the two coils of the winding advance coil 1 and the rewinding coil 10 can be arranged close to each other so as to be almost integrated with high accuracy, and the coil pitches can be arranged so as to overlap. Thereby, since the coil cross-sectional areas in the axial direction and the circumferential direction of the winding advance coil 1 and the rewinding coil 10 can be made almost equal with high accuracy, the flow of the magnetic field in the coil can be made smooth and the measurement sensitivity to the measurement magnetic field can be improved. Since the canceling effect can be improved with respect to an external magnetic field that does not require detection, the influence of the external magnetic field can be reduced to minimize the canceling error of the induced voltage and increase the current measurement accuracy.

  In addition, compared to a toroidal coil using a printed circuit board, a continuous toroidal coil can be formed from a single metal thin plate without joints or through-hole connections, so that the reliability of the coil can be improved. Moreover, since the toroidal coil by punching and bending can make the coil conductor thicker than the toroidal coil of the printed circuit board that requires etching, the conductor loss of the coil can be reduced. Furthermore, the coil structure is made three-dimensional, so that the inside of the coil air core can be made into a space, so that the dielectric loss of the coil can be reduced as compared with the conventional printed circuit board coil using the air core as a dielectric. it can. As a result, a low-cost current sensor that is small, high-performance, and easy to mass-produce can be realized.

  In the above-described various embodiments, the corner portion of the connecting portion that connects the radial lines is formed in a substantially rectangular shape. However, the corner portion may not be particularly rectangular, and the coil pattern only needs to be axially symmetric with respect to the coil central axis. . In addition to the current sensor, the various embodiments can be applied to a high-frequency choke coil, a signal filter, a small antenna, and various transformers.

The block diagram of the toroidal coil which concerns on the 1st Embodiment of this invention. (A) is a top view of the conductor pattern which forms the said coil, (b) is an enlarged view of the A section of (a). (A) is a figure explaining the refracting part bent, (b) is a figure which shows the refracting part after a bending process, (c) is a figure which shows the cross section of the circumferential direction of the said coil. The top view of the said coil, (b) is sectional drawing of the said coil. The block diagram of the alternating current detection coil by the toroidal coil structure which concerns on the 2nd Embodiment of this invention. The enlarged view of the center part of the said coil. (A), (b) is a top view of each conductor pattern used as the winding advance coil and rewinding coil in the said coil. (A) is an enlarged view of a C portion in FIG. 7 (a), and (b) is an enlarged view of a D portion in FIG. 7 (b). (A) is the elements on larger scale of FIG. 5 explaining the connection between coil extraction terminals, (b) is sectional drawing of (a). (A) is a top view of FIG. 5, (b) is the elements on larger scale of (a). The figure explaining the manufacturing process of the said coil. (A) is a block diagram of the alternating current detection coil by the toroidal coil structure concerning the 3rd Embodiment of this invention, (b) is a block diagram of the case of (a). (A) is a perspective view of the said coil, (b) is an enlarged view of E section of (a), (c) is sectional drawing of the circumferential direction of (b). The figure explaining the manufacturing process of the said coil. (A) is a block diagram of the alternating current detection coil by the toroidal coil structure which concerns on the 4th Embodiment of this invention, (b) is a perspective view of the winding advance coil of the said coil, (c) is winding of the said coil The perspective view of a return coil, (d) is each sectional drawing of (b) and (c). (A) is the elements on larger scale of the said coil, (b) is sectional drawing of the circumferential direction of (a). The top view of the said coil. (A) is a block diagram of the alternating current detection coil by the toroidal coil structure which concerns on the 5th Embodiment of this invention, (b) is a block diagram of the case of (a). The top view of Fig.18 (a). (A) is a figure explaining the positional relationship of the winding advance coil and rewinding coil of the said coil, (b) is a figure which shows the cross section of the circumferential direction of (a). The front view of the conventional coil for alternating current detection. The elements on larger scale of the said coil for a detection.

Explanation of symbols

1 Toroidal coil (coil body, winding advance coil)
10 Toroidal coil (coil body, rewinding coil)
2, 2a, 2b Conductor pattern 3, 31, 32 Radial line 32x Bending portion 100 Coil for alternating current detection (alternating current sensor)

Claims (3)

A coil is formed by punching a thin metal plate to form a spiral continuous conductor pattern in the circumferential direction, and alternately bending adjacently extending patterns of this conductor pattern in the thickness direction. and body,
The coil body has radial lines formed up and down in the thickness direction by patterns formed in steps,
The coil body is made into two types of coils, ie, a winding direction and a rewinding direction, and these two coils are arranged close to each other so that their radial lines overlap each other in the thickness direction. Rogowski coil structure characterized by connecting the starting ends . The two coil bodies are provided, and one coil is arranged upside down with respect to the other to form both the coil in the winding direction and the coil in the rewinding direction. The Rogowski coil structure according to claim 1 , wherein the start ends are connected. 3. The logo according to claim 1, wherein a bent pattern is provided in a part of the radially extending pattern in the punched state of the thin metal plate, and a bent portion having a step difference is formed by the bent pattern. Ski coil structure .