JP5196201B2 - Magnetic balanced current sensor - Google Patents

Description

  The present invention relates to a magnetic balance type current sensor that detects a current flowing through a bus bar in a non-contact manner.

2. Description of the Related Art Conventionally, a magnetic balance type sensor is known as a current sensor that detects a current flowing through a bus bar (current to be measured) in a non-contact state using a magnetic detection element such as a Hall element. As illustrated in FIG. 11, the magnetic balance type current sensor includes a ring-shaped magnetic core 820 having a gap G (such as a silicon steel plate or a permalloy core with high permeability and low residual magnetism), and a hole disposed in the gap G. An element 816 (an example of a magnetic detection element) and a negative feedback coil 830 in which a winding is provided on the magnetic core 820 are included. The magnetic core 820 is arranged so that the bus bar 810 through which the measured current I _in flows.

In this configuration, a first magnetic field is generated in the gap G by the measured current I _in and applied to the magnetic sensitive surface of the Hall element 816. The strength of the magnetic field is proportional to the measured current I _in. On the other hand, a negative feedback current is supplied to the negative feedback coil 830 so as to generate a second magnetic field that cancels (sets to zero) the first magnetic field applied to the magnetic sensitive surface of the Hall element 816. A current to be measured I _in is obtained from the supplied current. Note that the circuit configuration of the magnetic balance type current sensor is as shown in FIG. 12, for example. In this circuit, a negative feedback current is converted into a voltage by a detection resistor, which is amplified by a differential amplifier circuit to be a sensor output.

  Patent Document 1 below relates to a magnetic balance type current sensor and discloses a configuration in which a toroidal magnetic core is directly wound (toroidal winding).

JP 7-239347 A

  When the winding is directly applied to the toroidal core as in Patent Document 1, it takes more man-hours for manufacturing than the case where the bobbin is normally wound, and an expensive winding machine dedicated to the toroidal winding is required. It is necessary to use it. As a solution to these problems, it is possible to divide the bobbin for winding or the magnetic core, but an increase in the number of assembly steps is inevitable.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a magnetic balance type current sensor which does not require a toroidal winding and does not need to divide a bobbin or a magnetic core for winding. There is to do.

One embodiment of the present invention is a magnetically balanced current sensor. This magnetic balanced current sensor
A bus bar as a path for the current to be measured;
An annular magnetic core having a gap and through which the bus bar passes;
A magnetic sensing element located in the gap of the annular magnetic core;
And a benzalkonium yl unit to generate a second magnetic field that cancels out the first magnetic field generated in the gap by the current to be measured,
Before Kiko yl unit includes a winding which has been subjected to the bobbin and the bobbin, the inside of the winding through a part of the ring of the annular magnetic core, the length of the gap length of the winding axis direction Ri dimensioned der detachable from the annular magnetic core through said gap long and had a length less portion of the length difference the gap between the inner and outer diameter than is,
The bobbin integrally includes a magnetic detecting element holding portion in a flange portion of the winding axis direction one end side, the magnetic detection elements that are held in the magnetic detecting element holding portion.

Before Symbol magnetic detecting element holding portion, it is preferable to position the gap bottomed cylindrical shape which opens in a direction perpendicular to both the circumferential direction and the radial direction the annular magnetic core.

In an aspect of the magnetic balance type current sensor,
The bobbin has a core abutting portion facing at a virtual extension line and the intersection and the flange portion and the space of the bobbin winding axis before Kiko yl units together,
The core abutting portion may be in contact with a part of the outer peripheral surface of the annular magnetic core.

Another aspect of the present invention is a magnetically balanced current sensor. This magnetic balanced current sensor
A bus bar as a path for the current to be measured;
An annular magnetic core having a gap and through which the bus bar passes;
A magnetic sensing element located in the gap of the annular magnetic core;
A coil unit that generates a second magnetic field that cancels the first magnetic field generated in the gap by the current to be measured,
The coil unit includes a bobbin and a winding applied to the bobbin, a part of the ring of the annular magnetic core passes through the inside of the winding, and the length in the winding axis direction is longer than the length of the gap. It is long and has a dimensional configuration in which a difference in length between the inner diameter and the outer diameter is equal to or less than the length of the gap, and can be attached to and detached from the annular magnetic core through the gap.
The bus bar, comprising the annular magnetic core, and the case for positioning and holding the pre-Kiko yl unit,
The case has a bottom surface portion and a side surface portion that rises from the bottom surface portion, and has a shape that opens upward, and a partition wall portion that has an abutting surface that faces the inner surface of the side surface portion is formed from the bottom surface portion. Stand up,
It said annular magnetic core, a portion of the outer peripheral surface contacts the inner surface of the side portion, that portion of the inner peripheral surface is not in contact with the abutment surface of the partition wall portion.

Before SL annular magnetic core is a rectangular ring with rounded corners of the rectangle or square,
The partition wall portion has two contact surfaces that respectively contact the inner peripheral surfaces of two adjacent sides of the annular magnetic core,
At least one rib facing each contact surface is formed on the inner surface of the side surface portion,
The outer peripheral surfaces of the two sides of the annular magnetic core may be pressed against the ribs, and the inner peripheral surfaces of the two sides may be pressed against the contact surfaces of the partition walls.

Before SL pedestal portion from the bottom portion of the case rises, is equipped with a circuit board on said base portion, said annular magnetic core and pre-Kiko yl unit is present between the circuit board and the bottom portion, wherein It is preferable that the protrusion formed on the base part and the notch formed on the circuit board are engaged to position the circuit board on the base part.
The bobbin may integrally have a magnetic detection element holding portion at a flange on one end side in the winding axis direction, and the magnetic detection element may be held by the magnetic detection element holding portion.
The annular magnetic core may be a quadrangle or a square ring with rounded corners, and may have the gap in the middle of either side.
The annular magnetic core may be a rectangle or a rectangular ring with rounded corners, and may have the gap in the middle of one of the short sides.

  It should be noted that any combination of the above-described constituent elements, and those obtained by converting the expression of the present invention between methods and systems are also effective as aspects of the present invention.

  According to the present invention, the feedback coil has a portion in which the length in the winding axis direction is longer than the length of the gap, and the difference in length between the inner diameter and the outer diameter is equal to or less than the length of the gap. Because it is dimensionally detachable from the annular magnetic core through a gap, it is possible to realize a magnetically balanced current sensor that does not require a toroidal winding and that does not require a bobbin or magnetic core for winding. It is.

The perspective view of the magnetic balance type current sensor which concerns on the 1st Embodiment of this invention. The single-piece | unit perspective view of the annular magnetic core and feedback coil of the said magnetic balance type current sensor. The perspective view of the combined state of the said annular magnetic core and the said feedback coil. The single-piece | unit perspective view of the case of the said magnetic balance type current sensor. The perspective view at the time of circuit board mounting of the said magnetic balance type current sensor. The top view of the magnetic balance type current sensor which concerns on the 2nd Embodiment of this invention. The perspective view of the feedback coil of the said magnetic balance type current sensor. The perspective view of the resin mold body which integrated the bus bar of the said magnetic balance type current sensor, the annular magnetic core, and the sensor output terminal. The perspective view which saw through the inside of mold resin in FIG. The top view at the time of the circuit board mounting of the said magnetic balance type current sensor. The basic block diagram of the conventional magnetic balance type current sensor. The basic circuit diagram of the conventional magnetic balance type current sensor.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent component, member, etc. which are shown by each drawing, and the overlapping description is abbreviate | omitted suitably. In addition, the embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

(First embodiment)
FIG. 1 is a perspective view of a magnetic balance type current sensor according to a first embodiment of the present invention. FIG. 2 is a single perspective view of the annular magnetic core and feedback coil of the magnetically balanced current sensor. FIG. 3 is a perspective view of a combined state of the annular magnetic core and the feedback coil. FIG. 4 is a single perspective view of the case of the magnetic balance type current sensor. FIG. 5 is a perspective view of the magnetic balanced current sensor when mounted on a circuit board.

  As shown in FIG. 1, the magnetic balanced current sensor of the present embodiment includes a bus bar 11, an annular magnetic core 13, a Hall element 15 as a magnetic detection element, a feedback coil 20, and a case 50.

The bus bar 11 is a conductor serving as a path for the current to be measured. The annular magnetic core 13 made of a soft magnetic material is a rectangle or a rectangular ring with rounded corners as shown in FIG. 2, and has a gap 135 in the middle of the short side portion 13a. The bus bar 11 penetrates the inside of the annular magnetic core 13. The Hall element 15 is located in the gap 135 of the annular magnetic core 13. The feedback coil 20 is formed by winding a winding 29 on a winding body portion between both side flange portions 22 and 23 of the bobbin 21. Here, the feedback coil 20 means a coil unit including the bobbin 21 and the winding 29. A part (long side part 13b) of the ring of the annular magnetic core 13 passes through the inside of the feedback coil 20 (inside the winding body part). A negative feedback current is supplied to the feedback coil 20 so as to generate a second magnetic field that cancels the first magnetic field generated in the gap 135 by the current to be measured flowing through the bus bar 11. The winding body of the feedback coil 20 has a straight cylindrical shape, and the winding 29 can be applied to the bobbin 21 with a normal winding machine. Both ends of the winding 29 are entangled with terminals 205 and 206, respectively, and soldered or the like (not shown).

  As shown in FIG. 2, the length Lc of the feedback coil 20 in the winding axis direction is longer than the length Lg of the gap 135 (Lc> Lg). On the other hand, the difference in the length between the inner diameter and the outer diameter of the feedback coil 20 (the thickness in the radial direction) is not more than the length Lg of the gap 135 (Ld ≦ Lg in FIG. 2). The inner diameter of the feedback coil 20 (the inner diameter of the bobbin body of the bobbin 21), that is, the diameter of the core insertion hole 201 is set so that the feedback coil 20 can be attached to and detached from the annular magnetic core 13 by passing the portion through the gap 135. The dimensions are set.

  The bobbin 21 is formed of insulating resin or the like so as to integrally have a magnetic detection element holding portion 25 on the flange portion 22 on one end side in the winding axis direction. The magnetic detection element holding unit 25 is, for example, a bottomed rectangular tube shape that is open on one side in a direction perpendicular to both the circumferential direction and the radial direction of the annular magnetic core 13, and one of the side surfaces is an end surface of the flange portion 22. It is a part. The width Wh of the magnetic detection element holding part 25 is equal to or slightly shorter than the length Lg of the gap 135 of the annular magnetic core 13. The hall element 15 is accommodated and held in the magnetic detection element holding unit 25. The internal dimension of the magnetic detection element holding unit 25 is set so that the Hall element 15 is accommodated without rattling. For example, rattling can be prevented while ensuring the ease of insertion of the Hall element 15 by providing the magnetic detection element holding part 25 with a portion that becomes smaller in diameter as it approaches the bottom side from the opening side.

  The bobbin 21 integrally includes a core abutting portion 27 that intersects with a virtual extension line of the winding axis of the feedback coil 20 and faces the flange portion 22 of the bobbin 21 with a space therebetween. The core abutting portion 27 exists so as to pass the two leg portions 28 a and 28 b rising from the position where the core insertion hole 201 is sandwiched on the end surface of the flange portion 22. The leg portion 28a constitutes one of the side surfaces of the magnetic detection element holding portion 25 described above. Between the core abutting portion 27 and the flange portion 22 with respect to the winding axis direction of the feedback coil 20, the above-described magnetic detection element holding portion 25 is located. As shown in FIG. 3, the core abutment portion 27 abuts on a part of the outer peripheral surface of the annular magnetic core 13 (the outer peripheral surface of the lower side portion 13 a on the lower side of the gap 135). The position of the feedback coil 20 with respect to the annular magnetic core 13 is determined in a state where the magnetic detection element holding unit 25 and the Hall element 15 held thereby are positioned in the gap 135.

  As shown in FIG. 1, the case 50 positions and holds the bus bar 11, the annular magnetic core 13, and the feedback coil 20. The case 50 is formed integrally with the bus bar 11 by, for example, insert resin molding.

  As shown in FIG. 4, the case 50 has a substantially rectangular bottom surface portion 51 and side surface portions 52 a to 52 d that rise from the respective edges of the bottom surface portion 51, and has an open shape at the top. Two ribs 501 and 502 are formed on the inner surface of the side surface portion 52 c, and a partition wall portion 503 having a contact surface facing the ribs 501 and 502 rises from the bottom surface portion 51. Two ribs 511 and 512 are formed on the inner surface of the side surface portion 52 d, and a partition wall portion 513 having a contact surface facing the ribs 511 and 512 rises from the bottom surface portion 51. The partition wall portions 503 and 513 may be integrated with each other, or may be separately raised from the bottom surface portion 51. The end portions of the abutting surfaces of the partition walls 503 and 513 are R surfaces that match the curvature of the inner peripheral corner of the annular magnetic core 13.

  In the state shown in FIG. 1, the annular magnetic core 13 has a part of the outer peripheral surface (the outer peripheral surfaces of the short side portion 13 c and the long side portion 13 d) on the ribs 501, 502, 511, 512 (not shown in the figure). By being pressed, a part of the inner peripheral surface (the inner peripheral surfaces of the short side portion 13c and the long side portion 13d) is pressed against the contact surfaces of the partition wall portions 503 and 513. This ensures the positioning of the annular magnetic core 13 in the case 50.

  On the other hand, the side surface of the terminal block 202 formed on the flange portion 22 of the bobbin 21 contacts the side surface portions 52a and 52b of the case 50, and the outer surface of the core abutting portion 27 contacts the side surface portion 52a. The side surface of the formed terminal block 203 contacts the side surface portion 52b. Thereby, the feedback coil 20 is positioned in the case 50. At this time, a part of the inner peripheral surface (the inner peripheral surface of the winding drum portion) of the bobbin 21 abuts on the outer peripheral surface of the long side portion 13b of the annular magnetic core 13, and the core abutting portion 27 of the annular magnetic core 13 is as described above. It is in contact with a part of the outer peripheral surface, and the relative positional relationship between the annular magnetic core 13 and the feedback coil 20 is accurately determined.

  As shown in FIGS. 1 and 4, for example, the bus bar 11 integrally formed with the case 50 at the time of insert resin molding of the case 50 enters the case 50 from the side surface portion 52c, penetrates the bottom surface portion 51 and the partition wall portion 503, Projecting from the upper surface of the partition wall 503. That is, one end of the bus bar 11 protrudes from the side surface portion 52c to the side, and the other end protrudes from the upper surface of the partition wall portion 503 and is bent and extends to the side via the side surface portion 52c. The bus bar 11 protrudes upward from the upper surface of the partition wall 503 as shown in FIG. 4 before the annular magnetic core 13 is accommodated in the case 50, and after the annular magnetic core 13 is accommodated in the case 50. It is bent as shown in FIG.

  The sensor output terminal 60 is formed integrally with the case 50 together with the bus bar 11 at the time of insert resin molding of the case 50, for example. The sensor output terminal 60 is, for example, an L pin terminal, and one end projects sideways from the side surface portion 52 c and the other end projects upward from a predetermined position of the bottom surface portion 51.

  The protruding position from the side surface portion 52c at one end of the bus bar 11 and the protruding position from the side surface portion 52c at one end of the sensor output terminal 60 ensure the creeping distance for insulation and avoid the mutual interference. In the vicinity, the corners are different from each other so that the distance is as far as possible.

  Base parts 551, 552, and 553 (the base part 553 appears only in FIG. 4) rise from the bottom surface part 51 of the case 50. The partition wall part 513 also serves as a base part. The base portions 551, 552, and 553 may be integrally formed as a part of the side wall portions 52a, 52b, and 52c, or may rise from the bottom surface portion 51 separately from the side wall portions 52a, 52b, and 52c. As shown in FIG. 5, the circuit board 70 is mounted on the upper surfaces of the base parts 551, 552, 553 and the partition wall part 513. The annular magnetic core 13 and the feedback coil 20 exist between the bottom surface portion 51 and the circuit board 70. The protrusions 551a and 513b formed on the upper surfaces of the base portion 551 and the partition wall portion 513 are engaged with the notches 701 and 703 formed on the circuit board 70 so that the circuit board 70 is connected to the base portions 551, 552, and 553 and the partition. It is positioned on the upper surface of the wall portion 513. The terminals 205 and 206 of the feedback coil 20 and the terminal 155 of the Hall element 15 are inserted into the through holes of the circuit board 70 and connected to a wiring pattern (not shown) on the circuit board 70 side. Although not shown, a known circuit for obtaining an output voltage as a magnetic balance type current sensor is formed on the circuit board 70.

  After the circuit board 70 is mounted, the case 50 is filled with an insulating resin, and the annular magnetic core 13, the feedback coil 20, the Hall element 15, and the circuit board 70 are fixed in the case 50. Note that the notches 703 and 705 of the circuit board 70 and the central low-profile portion 513a of the partition wall portion 513 are convenient paths for resin injection.

  A procedure for manufacturing (assembling) the magnetic balanced current sensor according to the present embodiment will be described below.

  First, the winding 29 is applied to the bobbin 21 with a normal winding machine to process the winding end, and the feedback coil 20 shown in FIG. 2 is created. Next, the feedback coil 20 is combined with the annular magnetic core 13 as shown in FIG. The Hall element 15 may be accommodated and held in the magnetic detection element holding unit 25 either before or after the feedback coil 20 is combined with the annular magnetic core 13. Thereafter, the combination of the feedback coil 20 and the annular magnetic core 13 is accommodated and positioned in the case 50 shown in FIG. 4, and the bus bar 11 is bent as shown in FIG. Then, the circuit board 70 is mounted in the case 50 as shown in FIG. Finally, the interior of the case 50 is filled with insulating resin, and each part is hardened.

  According to the present embodiment, the following effects can be achieved.

(1) There is a portion where the difference in length between the inner diameter and the outer diameter of the feedback coil 20 is equal to or less than the length Lg of the gap 135, and the feedback coil 20 is connected to the annular magnetic core 13 by passing the portion through the gap 135. Since the inner diameter dimension of the feedback coil 20 is set so as to be detachable, the length Lc in the winding axis direction is longer than the length Lg of the gap 135 and is already wound by a normal winding machine. Can be easily attached to the annular magnetic core 13. For this reason, the conventional toroidal winding is unnecessary, and it is not necessary to divide the bobbin 21 or the annular magnetic core 13. Therefore, the assembly workability is good and the cost is advantageous.

(2) The core abutting portion 27 is in contact with the outer peripheral surface of the lower side portion of the short side portion 13a of the annular magnetic core 13 so that the magnetic detection element holding portion 25 of the bobbin 21 and the holding portion 27 are held thereby. Since the position of the feedback coil 20 with respect to the annular magnetic core 13 is accurately determined with the Hall element 15 in the gap 135, the assembly workability is improved and the detection accuracy as a sensor is also improved.

(3) Since the magnetic detection element holding part 25 is integrally formed on the bobbin 21 of the feedback coil 20, the annular magnetic core 13 and the feedback coil 20 are held in a state where the Hall element 15 is accommodated and held in the magnetic detection element holding part 25. It can be accommodated in the case 50, and the assembly workability is better than the case where the Hall element 15 is directly held by the case 50 separately from the bobbin 21, and the relative position of the Hall element 15 with respect to the annular magnetic core 13 is accurate. Therefore, the detection accuracy as a sensor is improved.

(4) Since the gap 135 is in the middle of the short side portion 13a of the annular magnetic core 13, the leakage magnetic flux is less than that in the case where the gap 135 is located at the end portion of the short side portion 13a. Moreover, since the long side part 13b penetrates the inside of the feedback coil 20, the gap 135 is in the middle of the long side part, and compared with the case where the short side part penetrates the inside of the feedback coil 20, the feedback coil 20 It is preferable because the length in the winding axis direction can be increased, and the necessary number of windings can be easily secured.

(Second Embodiment)
FIG. 6 is a plan view of a magnetic balanced current sensor according to the second embodiment of the present invention. FIG. 7 is a perspective view of the feedback coil 20 of the magnetic balanced current sensor. FIG. 8 is a perspective view of a resin mold body in which the bus bar 11, the annular magnetic core 13, and the sensor output terminal 60 of the magnetic balance type current sensor are integrated with a mold resin 80. FIG. 9 is a perspective view of the inside of the mold resin 80 shown in FIG. FIG. 10 is a plan view of the magnetic balanced current sensor when mounted on a circuit board.

  In the present embodiment, unlike the first embodiment, as shown in FIGS. 8 and 9, the bus bar 11, the annular magnetic core 13, and the sensor output terminal 60 are formed by, for example, insert molding using a mold resin 80 as a support. It is integrated with. One end and the other end of the bus bar 11 protrude outward from the vicinity of the corner of the side surface 89 of the resin mold body 80 in order to ensure a creeping distance from the sensor output terminal 60. Further, as shown in FIG. 7, the bobbin 21 of the feedback coil 20 has an extension part 272 that extends the core abutting part 27, unlike the one of the first embodiment shown in FIG. Convex portions 231 and 232 projecting outward from the side surface of 203 in parallel with the winding axis direction.

  At the time of assembly, as shown in FIG. 6, the feedback coil 20 is attached to the annular magnetic core 13 integrated with the bus bar 11 and the sensor output terminal 60 by the mold resin 80 as in the first embodiment. At this time, the convex portions 231 and 232 (see FIG. 7) of the bobbin 21 are fitted into the concave portions 241 and 242 (see FIG. 9) of the side surface 85 of the mold resin 80. Further, since the through hole 273 (see FIG. 7) of the extension 272 of the bobbin 21 communicates with the female screw hole 81 (see FIG. 9) on the side surface 84 of the mold resin 80, a screw (not shown) is inserted into the through hole 273. And screwed into the female screw hole 81. Further, a screw (not shown) is inserted into the through hole 83 of the bottom surface portion 82 of the mold resin 80 and screwed into a female screw hole (not shown) of the terminal block 202 of the bobbin 21. Thereby, the feedback coil 20 is fixed to the mold resin 80 as shown in FIG.

  The Hall element 15 is accommodated in the magnetic detection element holding portion 25 of the bobbin 21 in the same manner as in the first embodiment before or after the feedback coil 20 is attached to the annular magnetic core 13. The circuit board 70 is mounted on the upper surface of the mold resin 80 as shown in FIG. Here, the circuit board 70 is fixed to the mold resin 80 by inserting a screw (not shown) through the through hole 77 of the circuit board 70 and screwing it into the female screw hole 87 on the upper surface of the mold resin 80. This embodiment also has the same effect as the first embodiment.

  The present invention has been described above by taking the embodiment as an example. However, it will be understood by those skilled in the art that various modifications can be made to each component of the embodiment within the scope of the claims. Hereinafter, modifications will be described.

  The magnetic detection element may be, for example, an MR element instead of the Hall element 15 illustrated in the embodiment.

  The annular magnetic core 13 may be a trapezoid other than a rectangle or other quadrangle, or a rectangular ring with rounded corners, and may have a gap in the middle of either side. Alternatively, the annular magnetic core 13 may be annular or elliptical.

  The gap 135 is not limited to the short side portion of the annular magnetic core 13 and may be formed in the middle of the long side portion. In this case, although it is necessary to shorten the length of the feedback coil 20 in the winding axis direction, the same effects as in the embodiment can be obtained in other respects.

  The four ribs 501, 502, 511, and 512 of the embodiment may be partially or completely omitted. For example, any of the ribs 501 and 502 and any of the ribs 511 and 512 may be omitted. Alternatively, if the backlash can be sufficiently reduced by sandwiching the annular magnetic core 13 between the side surface portion 52c and the partition wall portion 503, and the side surface portion 52d and the partition wall portion 513, no ribs may be provided.

11 Busbar 13 Annular Magnetic Core 15 Hall Element 20 Feedback Coil 21 Bobbin 22, 23 Gutter 29 Winding 50 Case 135 Gap

Claims (9)

A bus bar as a path for the current to be measured;
An annular magnetic core having a gap and through which the bus bar passes;
A magnetic sensing element located in the gap of the annular magnetic core;
And a benzalkonium yl unit to generate a second magnetic field that cancels out the first magnetic field generated in the gap by the current to be measured,
Before Kiko yl unit includes a winding which has been subjected to the bobbin and the bobbin, the inside of the winding through a part of the ring of the annular magnetic core, the length of the gap length of the winding axis direction Ri dimensioned der detachable from the annular magnetic core through said gap long and had a length less portion of the length difference the gap between the inner and outer diameter than is,
The bobbin integrally includes a magnetic detecting element holding portion in a flange portion of the winding axis direction one end side, the magnetic detection elements that are held in the magnetic detecting element holding portion, the magnetic balance type current sensor. The magnetic balance type current sensor according to claim 1 , wherein the magnetic detection element holding portion has a bottomed cylindrical shape opened in a direction perpendicular to both a circumferential direction and a radial direction of the annular magnetic core and is positioned in the gap. Magnetic balance type current sensor. In the magnetic balance type current sensor according to claim 1 or 2 ,
The bobbin has a core abutting portion facing at a virtual extension line and the intersection and the flange portion and the space of the bobbin winding axis before Kiko yl units together,
The magnetic balance type current sensor, wherein the core abutting portion is in contact with a part of the outer peripheral surface of the annular magnetic core. A bus bar as a path for the current to be measured;
An annular magnetic core having a gap and through which the bus bar passes;
A magnetic sensing element located in the gap of the annular magnetic core;
A coil unit that generates a second magnetic field that cancels the first magnetic field generated in the gap by the current to be measured,
The coil unit includes a bobbin and a winding applied to the bobbin, a part of the ring of the annular magnetic core passes through the inside of the winding, and the length in the winding axis direction is longer than the length of the gap. It is long and has a dimensional configuration in which a difference in length between the inner diameter and the outer diameter is equal to or less than the length of the gap, and can be attached to and detached from the annular magnetic core through the gap.
The bus bar, comprising the annular magnetic core, and the case for positioning and holding the pre-Kiko yl unit,
The case has a bottom surface portion and a side surface portion that rises from the bottom surface portion, and has a shape that opens upward, and a partition wall portion that has an abutting surface that faces the inner surface of the side surface portion is formed from the bottom surface portion. Stand up,
The annular magnetic core is a magnetic balance type current sensor in which a part of an outer peripheral surface is in contact with an inner surface of the side surface part and a part of an inner peripheral surface is in contact with the contact surface of the partition wall part. The magnetic balance type current sensor according to claim 4 ,
The annular magnetic core is a square or a square ring with rounded corners,
The partition wall portion has two contact surfaces that respectively contact the inner peripheral surfaces of two adjacent sides of the annular magnetic core,
At least one rib facing each contact surface is formed on the inner surface of the side surface portion,
The magnetic balance type current sensor, wherein the outer peripheral surfaces of the two sides of the annular magnetic core are pressed against the ribs, and the inner peripheral surfaces of the two sides are pressed against the contact surfaces of the partition walls, respectively. . The magnetic balance type current sensor according to claim 4 or 5 , wherein a base portion rises from a bottom surface portion of the case, a circuit board is mounted on the base portion, and the circuit board is interposed between the bottom surface portion and the circuit board. there is an annular magnetic core and pre-Kiko yl unit, the circuit board formed projections and the notches formed in said circuit board engages on the base part is positioned on the base portion Magnetic balance type current sensor. The magnetic balance type current sensor according to any one of claims 4 to 6, wherein the bobbin integrally has a magnetic detection element holding portion at a flange on one end side in the winding axis direction, and the magnetic detection element is the magnetic sensor. A magnetic balance type current sensor held in a detection element holding unit. The magnetic balanced current sensor according to any one of claims 1 to 7 , wherein the annular magnetic core is a quadrangle or a square ring with rounded corners, and the gap is provided in the middle of either side. Balanced current sensor. In the magnetic balance type current sensor according to any of claims 1 to 7, wherein the annular magnetic core is a rectangular ring with rounded corners of a rectangle or rectangular, with the gap in the middle of the short side portion of either Magnetic balance type current sensor.