JP2014085278A - Current sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current sensor of a new structure, capable of suppressing a temperature rise in a case, and stably keeping detection accuracy.SOLUTION: On a detected portion 17 of a bus bar 15 inserted in a case 40 and a magnetic body core 34, a rising portion 20 bent and raised by a bending line 18 extending in an extending direction of the detected portion 17 is formed. In the case 40 in which the detected portion 17 is inserted, a hollow insertion hole 68 extending while having a crosse sectional shape larger than a rectangular area surrounding the whole of the cross section of the detected portion 17 including the rising portion 20 is formed. By inserting the detected portion 17 in the hollow insertion hole 68, a hollow portion 94 is formed between an inner surface 72 of the hollow insertion hole 68 and the detected portion 17.

Description

  The present invention relates to a current sensor that detects a current flowing through a conductor, and more particularly to a current sensor that detects a current flowing through a bus bar as a conductor.

  Conventionally, a current sensor has been used to detect a charging / discharging current of a battery of a car or a current flowing between a battery of a hybrid car or an electric car and an inverter. As described in Japanese Patent Application Laid-Open No. 2012-63256 (Patent Document 1), the current sensor includes an annular magnetic core and a magnetoelectric conversion element such as a Hall element. A magnetoelectric conversion element is disposed in a gap portion formed by dividing the portion, and a conductor is inserted through the magnetic core. The magnetic current generated by the current flowing through the conductor is converted into a voltage signal by the magnetoelectric conversion element, so that the current flowing through the conductor is detected.

  By the way, the magnetoelectric conversion element needs to be accurately positioned within the gap of the magnetic core. Therefore, the magnetic core and the magnetoelectric conversion element are positioned relative to each other by being housed in a synthetic resin case. And the to-be-detected part of a conductor is penetrated in a case, and is penetrated by the magnetic body core arrange | positioned in a case.

  However, in a current sensor having a conventional structure, heat is easily generated inside the case, and when a current flows through a conductor inserted into the case, the temperature inside the case rises due to Joule heat, and the detection accuracy of the magnetoelectric conversion element decreases. There was a fear. In particular, the bus bar has a problem that a high current flows, so that the bus bar tends to become high temperature, and the temperature rise inside the case is more remarkable.

JP 2012-63256 A

  The present invention has been made in the background of the above-mentioned circumstances, and the solution is to suppress the temperature rise inside the case and to maintain the detection accuracy stably. It is to provide a sensor.

  According to a first aspect of the present invention, there is provided an annular magnetic core in which a part of the circumference is divided to form a gap portion, and a bus bar disposed in the gap portion and inserted through the magnetic core. In a current sensor in which a magnetoelectric conversion element that detects a magnetic flux that changes according to a current flowing through a detected portion is housed in a case, the detected portion of the bus bar extends in the extending direction of the detected portion. While the upright portion that is bent and raised at the bending line is formed, the case has a hollow insertion that extends with a larger cross-sectional shape than a rectangular region that surrounds the entire cross section of the detected portion including the upright portion. A hole is formed, and the detected portion of the bus bar is inserted into the hollow insertion hole, so that a hollow portion is formed between the inner surface of the hollow insertion hole and the detected portion. Is a feature.

  In the current sensor having the structure according to the present invention, the raised portion is formed in the detected portion of the bus bar that is inserted into the case, and the raised portion is formed in the cross section of the hollow insertion hole that passes through the detected portion. The cross-sectional shape is larger than the rectangular area surrounding the entire detected portion. As a result, the detected part inserted through the hollow insertion hole and the inner surface of the hollow insertion hole are separated by at least the height dimension of the upright portion, and the hollow part is formed between the inner surface of the hollow insertion hole and the detected part. Is formed. And the temperature rise of a to-be-detected part can be suppressed by making the air in a hollow part and the to-be-detected part contact, and increasing the contact amount with the air of a to-be-detected part. As a result, the temperature rise inside the case can be suppressed, and the detection accuracy can be stably maintained.

  Note that the cross-sectional shape of the hollow insertion hole may be changed inside the case. In addition, various shapes can be adopted as the specific shape of the detected portion of the bus bar, such as an L-shaped cross section in which one upright portion is formed and a U-shaped shape in which two upright portions are formed. A cross section is also acceptable. Further, the detected portion may be formed in a cylindrical shape by turning the upright portion in the circumferential direction.

  According to a second aspect of the present invention, in the first aspect, the outer case includes an outer case that accommodates the detected portion of the bus bar protruding from the case together with the case. The wall portions located on both sides in the extending direction of the detected portion are provided with external vents that open on the extension of the detected portion.

  In the current sensor having the structure according to this aspect, the hollow insertion hole is communicated with the outside of the outer case through the external ventilation hole penetrating the outer case. Accordingly, air outside the outer case can be taken into the hollow insertion hole, and air inside the hollow insertion hole can be discharged to the outside of the outer case to cool the detected portion inside the hollow insertion hole. As a result, the temperature rise inside the case can be reduced and the detection accuracy can be maintained more stably.

  According to a third aspect of the present invention, in the first or second aspect, a bus bar support rib is formed on an inner surface of the hollow insertion hole, and the detected portion of the bus bar is the It is supported by the bus bar support rib with a gap from the inner surface of the hollow insertion hole.

  According to this aspect, the detected part of the bus bar is disposed with a gap with respect to the inner surface of the hollow insertion hole. Thereby, the heat transfer from the bus bar to the case can be reduced. As a result, the temperature rise in the case can be suppressed and the detection accuracy of the magnetoelectric transducer can be maintained.

  According to a fourth aspect of the present invention, there is provided the support according to any one of the first to third aspects, wherein the case is formed with a support portion that is inserted through the magnetic core and supports the magnetic core. And a core support rib is formed on the outer surface of the support portion, and the magnetic core is supported by the core support rib with a gap from the outer surface of the support portion. is there.

  According to this aspect, the magnetic core is disposed with a gap with respect to the support portion of the case. Thereby, the heat transfer from the case to the magnetic core can be reduced. As a result, the temperature rise in the case can be suppressed and the detection accuracy of the magnetoelectric transducer can be maintained.

  According to a fifth aspect of the present invention, in the one described in any one of the first to fourth aspects, the cross-sectional shape of the detected part of the bus bar has a pair of upright portions at both ends. It is a shape.

  According to this aspect, the surface area and the current-carrying cross-sectional area of the detected part can be further increased by forming the raised portions on both sides of the detected part. As a result, the temperature rise of the detected part can be more effectively suppressed.

  In the current sensor of the present invention, the raised portion is formed in the detected portion of the bus bar, and the hollow insertion hole through which the detected portion is inserted is larger than the rectangular region surrounding the entire cross section of the detected portion including the raised portion. It was formed with a cross-sectional area. Thereby, a hollow part can be formed between the inner surface of the hollow insertion hole and the detected part, and the detected part can be brought into contact with the air in the hollow part to reduce the temperature rise of the detected part. . As a result, the temperature rise inside the case can be suppressed, the thermal effect on the magnetoelectric conversion element can be reduced, and the detection accuracy can be stably maintained.

The perspective view of the current sensor as one embodiment of the present invention. The disassembled perspective view of the current sensor shown in FIG. The perspective view of the sensor main body which comprises the current sensor shown in FIG. The disassembled perspective view of the sensor main body shown in FIG. The top view of a bus bar. The perspective view of one case division body. The side view of one case division body shown in FIG. The perspective view of the other case division body. The principal part enlarged view of the side surface of the sensor main body shown in FIG. The principal part enlarged view of the front of the sensor main body shown in FIG. XI-XI sectional drawing in FIG. The top view of the current sensor shown in FIG. The principal part enlarged view of the XIII-XIII cross section in FIG. The principal part enlarged view of the XIV-XIV cross section in FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, FIG. 1 shows a main part of an electrical junction box 11 provided with a current sensor 10 as an embodiment of the present invention. As shown in FIG. 2, the current sensor 10 has a structure in which the sensor main body 12 is accommodated between the upper case 13 and the lower case 14 of the electrical connection box 11, and the upper case 13 and the lower case of the electrical connection box 11. 14 is configured as an outer case. In FIGS. 1 and 2 and FIGS. 9 to 14 described later, a part of a bus bar 15 described later is omitted.

  As shown in FIGS. 3 and 4, the sensor body 12 has a structure in which a core assembly 16 is assembled to a bus bar 15. As shown in FIG. 5, the bus bar 15 is an integrally formed product formed by bending a punched metal plate. The shape of the bus bar 15 can be set to an arbitrary shape according to the required wiring shape of the electric circuit. The bus bar 15 in the present embodiment is formed with a detected portion 17 extending with a certain width dimension (vertical direction dimension in FIG. 5). The detected part 17 has a pair of standing uprights that are bent vertically at bending edges 18 and 18 extending in the extending direction of the detected part 17 at both end edges in the width direction (vertical direction in FIG. 5). Upper portions 20, 20 are formed. In addition, the height dimension of the upright parts 20 and 20 is set to the height which can be inserted in the gap part 42 of the magnetic body core 34 mentioned later. Thereby, the to-be-detected part 17 is extended with the cross-sectional shape of a U-shape.

  Conductive paths 22a and 22b are extended from both sides of the detected portion 17 in the bus bar 15, and connecting portions 24a and 24b are formed at the extended ends of the conductive paths 22a and 22b, respectively. A bent portion 26a (see FIG. 4 and the like) that bends perpendicularly to the detected portion 17 is formed at a connection portion of the conductive path 22a with the detected portion 17. Further, a wide portion 28a having a larger width dimension (dimension in the vertical direction in FIG. 5) than the detected portion 17 is formed on the conductive path 22a from the bent portion 26a to the connection portion 24a side. Moreover, the connection part 24a is made into the flat plate shape by which the bolt hole 30 was penetrated by the center. For example, a connection terminal (not shown) provided at the terminal of the wire harness from the battery is bolted to the connection portion 24 a using the bolt hole 30. On the other hand, a bent portion 26b (see FIG. 4 and the like) similar to the bent portion 26a is also formed in the connection portion of the conductive path 22b with the detected portion 17. Further, a wide portion 28b having a larger width dimension (dimension in the vertical direction in FIG. 5) than the detected portion 17 is formed on the conductive path 22b from the bent portion 26b to the connection portion 24b side. A positioning hole 32 is provided in the wide portion 28b. Further, the conductive path 22b extends in a direction orthogonal to the extending direction of the detected portion 17 (left and right direction in FIG. 5), and a flat plate-like shape that rises vertically at the extending end portion. A connecting portion 24b is formed. A bolt hole 30 is formed through the connection portion 24b, and for example, a connection terminal (not shown) provided at the end of a wire harness connected to an electrical component is bolted. As described above, the conductive paths 22 a and 22 b continuing from the detected portion 17 include bent portions 26 a and 26 b that are bent with respect to the detected portion 17, and wide portions 28 a and 28 b that are larger in width than the detected portion 17. It is formed and is made larger than openings 76a and 76b of the case 40 described later in the projected view of the detected portion 17 in the extending direction (left and right direction in FIG. 5). Therefore, the bus bar 15 has such a size that it cannot be inserted into the openings 76 a and 76 b in the extending direction of the detected portion 17.

  The core assembly 16 is assembled to the detected portion 17 of the bus bar 15. As shown in FIG. 4, the core assembly 16 includes a magnetic core 34, a circuit board 38 including a Hall element 36 as a magnetoelectric conversion element, and a case 40 in which the magnetic core 34 and the circuit board 38 are assembled. It is comprised including.

  The magnetic core 34 is made of ferrite, silicon steel, or the like. The magnetic core 34 has an annular shape as a whole. The magnetic core 34 is formed with a gap portion 42 that is partly divided on the circumference.

  The Hall element 36 is an example of a magnetoelectric conversion element that can convert the strength of a magnetic field into a voltage signal. The hall element 36 is provided with a plurality of connection terminals 44 for power input and detection signal output.

  The hall element 36 is mounted on the circuit board 38 at the connection terminal 44. The circuit board 38 is mounted with a circuit for supplying power to the Hall element 36, a circuit for amplifying a magnetic flux detection signal output from the Hall element 36, a connector 46, and the like. The connector 46 is fixed to the circuit board 38 with a bolt 48 and is electrically connected to the Hall element 36 via a circuit provided on the circuit board 38. Thereby, the core assembly 16 can output a current detection signal to an external circuit such as an electronic control unit through an electric wire (not shown) connected to the connector 46.

  The case 40 is formed by combining one case divided body 50 and the other case divided body 52 with each other. FIG. 6 and FIG. 7 show one case division body 50. One case division body 50 is an integrally molded product formed of a synthetic resin. One case divided body 50 includes a substantially cylindrical support portion from a disc portion 54 having a partial disc shape in which a disc having a size substantially equal to the outer diameter of the magnetic core 34 is cut by a predetermined string. A shape 56 is projected. The support portion 56 has a substantially cylindrical shape having a slightly smaller diameter than the inner peripheral surface of the magnetic core 34, and is formed on the same central axis as the disc portion 54. The projecting dimension of the support part 56 from the disk part 54 is slightly larger than the axial dimension of the magnetic core 34. A plurality of core support ribs 58 extending in the axial direction of the support portion 56 are formed on the outer surface of the support portion 56 at appropriate positions in the circumferential direction. The core support ribs 58 are preferably formed at equal intervals in the circumferential direction of the support portion 56. In the present embodiment, the four core support ribs 58 are provided every 1/4 turn in the circumferential direction of the support portion 56. Is formed.

  Further, one case division body 50 is formed with a substrate mounting portion 60 that protrudes radially outward from the support portion 56 from the support portion 56. The board mounting portion 60 protrudes from the support portion 56 in the radial direction of the disk portion 54 and protrudes outward from the disk portion 54, and protrudes on both sides in the axial direction of the support portion 56 at the protruding tip portion. Has been. The width dimension of the substrate mounting portion 60 (the horizontal dimension in FIG. 7) is slightly smaller than the gap portion 42 of the magnetic core 34. A concave element housing portion 62 that opens to the outside of one case division body 50 is formed at the center portion of the substrate mounting portion 60. Bolt fixing portions 66 provided with bolt holes 64 are formed on both sides of the element mounting portion 62 in the substrate mounting portion 60.

  Further, a hollow insertion hole 68 is provided through the central portion of one case division body 50. The hollow insertion hole 68 has a rectangular cross section and extends in the axial direction of the support portion 56. As shown in FIG. 7, the rectangular cross section of the hollow insertion hole 68 has a dimension in the long side direction: L larger than a width dimension: w of the detected portion 17 of the bus bar 15 and a dimension in the short side direction: H. The vertical dimension of the raised portion 20 of the detected portion 17 is a rectangular shape larger than h. Thereby, the cross section of the hollow insertion hole 68 has a larger cross sectional shape than the rectangular region S that surrounds the entire cross section of the detected portion 17.

  The hollow insertion hole 68 has one side in the long side direction (right side in FIG. 7) opened to the linear end edge 70 in the disk portion 54, and three sides are surrounded by the inner surface 72. On the inner surface 72 of the hollow insertion hole 68, a plurality of bus bar support ribs 74 extending in the extending direction of the hollow insertion hole 68 are formed at appropriate positions in the circumferential direction.

  Such a hollow insertion hole 68 penetrates the disk portion 54 from the support portion 56, whereby an opening 76 a is formed in one case divided body 50. As a result, the opening 76a has a rectangular shape that opens on the disk portion 54 and has a notch shape that opens on the linear end edge 70 side. The cutout of the opening 76a is opened in a direction orthogonal to the extending direction of the detected portion 17 (left and right direction in FIG. 5) in a state where the case divided body 50 is assembled to the detected portion 17.

  Further, inside the support portion 56, lock insertion holes 78 and 78 penetrating the disc portion 54 and the support portion 56 are formed on both sides of the hollow insertion hole 68. Further, a pair of positioning recesses 80 and 80 are formed in the outer peripheral edge portion of the support portion 56. The positioning recesses 80 are formed at positions facing each other in the radial direction of the support portion 56.

  On the other hand, the other case division body 52 is shown in FIG. The other case divided body 52 is an integrally molded product formed from a synthetic resin. The other case divided body 52 is a disk portion 82 having a partial disk shape in which a disk having a size substantially equal to the disk portion 54 of the one case divided body 50 is cut by two orthogonal strings. have. In the central portion of the disk portion 82, a fitting recess 84 having a concave shape substantially equal to the outer shape of the protruding end surface of the support portion 56 in one case divided body 50 is formed.

  The disc portion 82 of the other case divided body 52 is provided with an opening 76b. The opening 76b has a rectangular shape having the same size as the opening 76a of the one case divided body 50. The opening 76 b has a cutout shape that opens to the linear end edge 86 of the disc portion 82. The linear edge portion 86 of the disc portion 82 is formed on the opposite side of the linear edge portion 70 in one case divided body 50 in the assembled state of one case divided body 50 and the other case divided body 52. Has been. Therefore, the notch of the opening 76b is opened in a direction perpendicular to the extending direction of the detected portion 17 in the assembled state of the other case divided body 52 to the detected portion 17, and It opens in the direction orthogonal to the extending direction in the direction opposite to the opening 76a of one case divided body 50.

  In the disc portion 82, lock pieces 88, 88 are formed at positions corresponding to the lock insertion holes 78, 78 of the one case divided body 50, respectively. The lock piece 88 has a protruding piece shape that protrudes from the disc portion 82 toward the one case split body 50, and a locking claw 90 is formed at the protruding tip portion from the disc portion 82. Further, in the disc portion 82, positioning bosses 92 and 92 projecting from the disc portion 82 toward the one case segment 50 are formed at positions corresponding to the positioning recesses 80 and 80 of the one case segment 50, respectively. Has been.

  As shown in FIG. 4, the core assembly 16 including the magnetic core 34, the circuit board 38, and the case 40 is assembled to the bus bar 15 as follows. First, the detected portion 17 of the bus bar 15 is inserted through the magnetic core 34 through the gap portion 42 of the magnetic core 34. The detected part 17 has a width dimension: w (see FIG. 7) larger than the gap part 42, but a height dimension including the upright portion 20: h (see FIG. 7) is made smaller than the gap part 42. Therefore, it can be inserted into the magnetic core 34 by being inserted into the gap portion 42 from the upright portion 20 side.

  Next, one case division body 50 is made to approach the detected portion 17 from the linear edge portion 70 side, and an opening 76a having a notch shape is formed from a direction orthogonal to the extending direction of the detected portion 17. Then, the detected portion 17 is inserted into the opening 76 a and the hollow insertion hole 68 by inserting the detected portion 17 into the hollow insertion hole 68. Then, the support portion 56 is inserted through the magnetic core 34 in a state where the gap portion 42 of the magnetic core 34 is aligned with the substrate mounting portion 60 of the one case divided body 50. The support 56 is inserted into the magnetic core 34 while the core support rib 58 is in contact with the inner peripheral surface of the magnetic core 34. As a result, the magnetic core 34 is supported by the support portion 56, and is assembled to the one case divided body 50 in a state where the substrate attachment portion 60 is inserted into the gap portion 42.

  Subsequently, the other case divided body 52 is brought close to the detected portion 17 from the opposite side of the one case divided body 50 in the direction orthogonal to the extending direction of the detected portion 17, and is formed into a cutout shape. By inserting the detected portion 17 into the portion 76b, the detected portion 17 is inserted through the opening 76b. Then, the lock pieces 88 and 88 of the other case divided body 52 are inserted into the lock insertion holes 78 and 78 of the one case divided body 50, and the positioning bosses 92 and 92 are fitted into the positioning recesses 80 and 80. After the alignment, the locking claws 90, 90 are engaged with the stepped surfaces formed inside the lock insertion holes 78, 78. As a result, as shown in FIG. 3, one case divided body 50 and the other case divided body 52 are assembled to each other with the magnetic core 34 sandwiched from both sides in the extending direction of the detected portion 17. The magnetic core 34 is accommodated in a case 40 constituted by one case divided body 50 and the other case divided body 52. The support portion 56 of one case divided body 50 inserted through the magnetic core 34 slightly protrudes from the magnetic core 34 and is fitted in the fitting recess 84 of the other case divided body 52. And the to-be-detected part 17 of the bus bar 15 is inserted into the case 40 through the openings 76a and 76b of the case 40, inserted into the magnetic core 34, and both ends in the extending direction of the to-be-detected part 17 are , Projecting from the openings 76a and 76b to the outside of the case 40. Further, as shown in FIG. 9, since the hollow insertion hole 68 has a rectangular cross section surrounding the entire cross-sectional shape of the detected portion 17, the detected portion 17 is inserted into the hollow insertion hole 68. A hollow portion 94 is formed between the inner surface 72 of the hollow insertion hole 68 and the detected portion 17. An opening 76a of one case divided body 50 and an opening 76b of the other case divided body 52 are opened in opposite directions, and the detected portion 17 is formed by one case divided body 50 and the other case divided body 52. Can be prevented from coming off from the detected portion 17. Further, as shown in FIG. 10, the magnetic core 34 is sandwiched from both sides in the axial direction (left and right direction in FIG. 10) between one case divided body 50 and the other case divided body 52. It can be held stably.

  Then, after the Hall element 36 is inserted into the element accommodating portion 62 of one case divided body 50, the circuit board 38 on which the connector 46 is mounted in advance is overlaid on the substrate mounting portion 60, and the connection terminal 44 of the Hall element 36. Is fixed to the board mounting portion 60 with bolts 95 and 95 in a state of being inserted into the through hole of the circuit board 38. Thereafter, the connection terminal 44 of the Hall element 36 is soldered to the circuit board 38. By soldering the Hall element 36 to the circuit board 38 after the Hall element 36 is inserted into the element accommodating portion 62, the Hall element 36 is fixed while being pressed against the bottom surface of the element accommodating portion 62. Can be avoided. As a result, the Hall element 36 is accommodated in the element accommodating portion 62 of the case 40 and disposed in the gap portion 42 of the magnetic core 34. As described above, as shown in FIGS. 3 and 9 to 11, the core assembly 16 is assembled, and the detected portion 17 of the bus bar 15 is connected to the openings 76 a and 76 b of the case 40 and the magnetic core 34. The sensor body 12 is assembled by being inserted.

  As shown in FIG. 2, the sensor main body 12 is accommodated between the upper case 13 and the lower case 14 of the electrical junction box 11. The upper case 13 is made of synthetic resin. A sensor housing portion 96 is formed in the upper case 13. The sensor housing portion 96 has a hollow, substantially rectangular box shape. A connector insertion hole 100 is provided in the outer wall 98a of the sensor housing portion 96. Further, external vents 102 and 102 are respectively provided through outer walls 98b and 98c which are located on both sides of the outer wall 98a and face each other. The external vents 102 and 102 are rectangular through holes having substantially the same size as the openings 76a and 76b of the sensor body 12, and are formed on the same straight line in the opposing direction of the outer wall 98b and the outer wall 98c. . In the upper case 13, a plurality of support protrusions 104 that protrude toward the lower case 14 are formed at appropriate positions.

  On the other hand, the lower case 14 is formed of a synthetic resin. A protective protruding wall 106 is erected on the lower case 14. Further, as shown in FIG. 13 to be described later, a support curved surface 108 extending with a curvature along the magnetic core 34 of the core assembly 16 is formed on the back side (right side in FIG. 13) of the protective protruding wall 106. Has been. Further, a pair of positioning protrusions 110 and 110 (only one of them is shown in FIG. 2) are provided on both sides of the edge portion of the support curved surface 108 opposite to the protective protruding wall 106.

  Then, the core assembly 16 of the sensor main body 12 is placed on the support curved surface 108 of the lower case 14 and the upper case 13 is put on the sensor main body 12, so that the core assembly as shown in FIG. 1 and FIG. The detected portion 17 of the solid 16 and the bus bar 15 is accommodated in the sensor accommodating portion 96 of the upper case 13, and the current sensor 10 is formed including the upper case 13 and the lower case 14. As shown in FIGS. 13 and 14, the core assembly 16 is placed on the support curved surface 108 along the magnetic core 34, and is sandwiched from both sides by a pair of positioning protrusions 110 and 110, and the lower case 14. Arranged above. Further, when the upper case 13 is put on the sensor main body 12, the support protrusion 104 a of the upper case 13 is inserted into the positioning hole 32 of the bus bar 15 and the sensor main body 12 is positioned with respect to the upper case 13 ( (See FIG. 1). Then, the connector 46 of the sensor main body 12 protrudes outside the upper case 13 through the connector insertion hole 100.

  Further, as the sensor case 12 is covered with the upper case 13, as shown in FIG. 14, the detection portion 17 of the bus bar 15 protruding from the core assembly 16 extends in the extending direction (left and right direction in FIG. 14). The outer walls 98b and 98c of the sensor accommodating part 96 are arrange | positioned on both sides. Then, the external vents 102 and 102 of the outer walls 98b and 98c are positioned on the extension line of the detected portion 17 and opened in the extending direction of the detected portion 17 (left and right direction in FIG. 14). The outer walls 98b and 98c are positioned in the immediate vicinity of the detected portion 17, and in this embodiment, the outer walls 98b and 98c are overlapped with the edge portions 112 and 112 of the detected portion 17 to form an external vent. The edge portions 112 and 112 of the detected portion 17 are positioned at 102 and 102, respectively.

  In such a current sensor 10, a magnetic field is generated in the gap portion 42 by focusing the magnetic flux generated by the current flowing through the detected portion 17 of the bus bar 15 on the magnetic core 34. The intensity of the magnetic field in the gap portion 42 that changes according to the current flowing through the detected portion 17 is detected by the Hall element 36 disposed in the gap portion 42 and converted into a voltage signal. The magnitude of the current flowing through the detection unit 17 can be detected. The voltage signal generated by the Hall element 36 is amplified by an amplifier circuit (not shown) provided on the circuit board 38 and transmitted to a control device such as an electronic control unit through the connector 46.

  According to the current sensor 10 having the structure according to the present embodiment, the upright portions 20 and 20 are formed in the detected portion 17 of the bus bar 15, and the hollow insertion hole 68 through which the detected portion 17 is inserted has the upright portion 20. , 20 having a larger cross-sectional shape than the rectangular region surrounding the entire cross-section of the detected portion 17, the hollow portion 94 is formed between the hollow insertion hole 68 and the detected portion 17. Thereby, the space in the hollow insertion hole 68 can be secured larger, and the heat in the detected portion 17 can be suppressed by bringing the air in the hollow portion 94 into contact with the detected portion 17. As a result, the temperature rise in the case 40 can be suppressed, and the detection accuracy of the Hall element 36 can be more stably ensured. Further, since the raised portions 20 and 20 are formed on the detected portion 17 and the surface area and cross-sectional area of the detected portion 17 are increased, the heat generation of the detected portion 17 can be reduced.

  Further, in the present embodiment, external vents 102, 102 that open on the extension of the detected portion 17 are formed in the upper case 13 as an outer case that houses the sensor body 12. As a result, the hollow insertion hole 68 is communicated with the outside of the upper case 13 through the external vents 102, 102, and air outside the upper case 13 is taken into the hollow insertion hole 68 and the air in the hollow insertion hole 68 is taken into account. Can be discharged to the outside of the upper case 13. As a result, the detected portion 17 can be air-cooled, and a more excellent heat generation suppression effect can be obtained. In particular, in the present embodiment, since the external vents 102 and 102 are positioned in the immediate vicinity of the edge 112 of the detected portion 17, the detected portion 17 is effectively in contact with the atmosphere outside the upper case 13. It can be made.

  Further, as shown in FIG. 13, the bus bar support rib 74 is formed on the inner surface 72 of the hollow insertion hole 68, and the detected portion 17 is supported by the bus bar support rib 74, so that a gap is formed with respect to the inner surface 72. They are spaced apart. Thereby, the heat transfer from the detected part 17 to the case 40 can be reduced, and the thermal influence on the Hall element 36 can be further reduced. Furthermore, a core support rib 58 is formed on the outer surface of the support portion 56, and the magnetic core 34 is supported by the core support rib 58, so that the support portion 56 is spaced from the support portion 56. Thereby, heat transfer from the case 40 to the magnetic core 34 can also be reduced, and the thermal influence on the Hall element 36 can be further reduced.

  Furthermore, in the current sensor 10 of the present embodiment, the openings 76a and 76b of one case divided body 50 and the other case divided body 52 constituting the case 40 of the sensor main body 12 are cut out. Thereby, both case division bodies 50 and 52 can be assembled | attached from the horizontal direction (the direction orthogonal to the extension direction of the to-be-detected part 17, the left-right direction in FIG. 14) with respect to the to-be-detected part 17 of the bus bar 15. . Then, by inserting the detected portion 17 through the magnetic core 34 through the gap portion 42 of the magnetic core 34, the detected portion 17 can be inserted through the openings 76 a and 76 b of the case 40 and the magnetic core 34. I can do it. Accordingly, even in the complicated shape of the bus bar 15 that has the bent portions 26a and 26b and the wide portions 28a and 28b in the portion other than the detected portion 17 and it is difficult to insert the detected portion 17 through the opening of the through hole shape, The core assembly 16 can be assembled to the detected portion 17.

  And since the connection parts 24a and 24b which connect with the connection terminal etc. of an electric wire etc. are integrally formed in the bus bar 15, the bus bar which protruded from the case like other current bars is connected with other bus bars. It is unnecessary to do. Therefore, the problem of heat generation caused by the contact resistance between the bus bars can be avoided, and the temperature rise of the detected portion 17 can be more effectively suppressed. In addition, since the overall dimensions of the bus bar 15 are increased and heat is dispersed over a wide range, the temperature rise of the detected portion 17 can be suppressed. In addition, since the connecting portions 24a and 24b are integrally formed on the bus bar 15, the work of connecting the detected portion 17 to another bus bar is not necessary, and the detected portion 17 and the other are connected to manage the contact resistance. It is no longer necessary to manage the contact pressure with the bus bar, and the number of manufacturing steps can be reduced.

  The current sensor 10 in the present embodiment is configured to include the upper case 13 and the lower case 14 as an outer case that accommodates the sensor body 12 and the detected portion 17 of the bus bar 15. The outer case may not be provided, and only the sensor body 12 in the present embodiment may be used. Even in such a current sensor, as described above, the rising portions 20 and 20 of the detected portion 17 and the hollow portion 94 in the hollow insertion hole 68 can suppress the heat generation of the detected portion 17, and the detection accuracy. Can be secured stably.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited by the specific description. For example, the detected portion of the bus bar may have an L-shaped cross section in which an upright portion is formed only on one side in the width direction, or may have a cylindrical shape in which the upright portion is formed. good. The cross-sectional shape of the hollow insertion hole is not necessarily limited to a rectangular shape, and may be, for example, a trapezoidal shape or other polygonal shapes.

  Further, as described above, the outer case is not necessarily required, but the outer case is not limited to the case of the electrical junction box as in the above embodiment, and the outer case that accommodates the detected portion of the bus bar is individually provided. A current sensor that can be attached to any place may be formed. Further, in the above-described embodiment, the circuit board 38 provided with the Hall element 36 is disposed outside the case 40 and covered with the upper case 13 as the outer case. However, the circuit board 38 includes an outer case. If not, the circuit board 38 may be accommodated in the case 40.

  Furthermore, in the above-described embodiment, the core assembly 16 can be assembled to the large bus bar 15 in which the connection portions 24a and 24b to the electric wires are integrally formed with the detected portion 17 by employing the case 40 having a specific shape. However, this is only an example, and the present invention is a case-structured current sensor that is combined with each other from both sides in the extending direction of the detected portion of the bus bar as shown in Patent Document 1. The present invention is also applicable to a current sensor in which only the detected portion of the bus bar inserted through the magnetic core and the case is individually formed and connected to another bus bar or the like. The shape of the magnetic core is not limited to an annular shape, and may be a rectangular annular shape.

10: current sensor, 11: electrical junction box, 12: sensor body, 13: upper case (outer case), 14: lower case (outer case), 15: bus bar, 16: core assembly, 17: detected part, 18 : Bending line, 20: upright part, 34: magnetic core, 36: Hall element (magnetoelectric conversion element), 40: case, 42: gap part, 50: one case division, 52: other case division, 58: Core support rib, 68: Hollow insertion hole, 72: Inner surface, 74: Busbar support rib, 76a, b: Opening part, 94: Hollow part, 96: Sensor accommodating part, 98a-c: Outer wall, 102: External ventilation mouth

Claims (5)

An annular magnetic core in which a part of the circumference is divided to form a gap portion, and a current that is arranged in the gap portion and flows through a detected portion of a bus bar that is inserted through the magnetic core. In a current sensor in which a magnetoelectric conversion element for detecting a changing magnetic flux is housed in a case,
The detected portion of the bus bar is formed with a raised portion that is bent and raised by a bending line extending in the extending direction of the detected portion,
In the case, a hollow insertion hole extending with a larger cross-sectional shape than a rectangular region surrounding the entire cross section of the detected portion including the upright portion is formed,
The current sensor, wherein the detected portion of the bus bar is inserted into the hollow insertion hole, so that a hollow portion is formed between the inner surface of the hollow insertion hole and the detected portion. An outer case that houses the detected portion of the bus bar protruding from the case together with the case;
2. The current sensor according to claim 1, wherein in the outer case, an external vent opening that opens on an extension of the detected portion is provided in a wall portion positioned on both sides in the extending direction of the detected portion. A bus bar support rib is formed on the inner surface of the hollow insertion hole, and the detected portion of the bus bar is supported by the bus bar support rib with a gap from the inner surface of the hollow insertion hole. The current sensor according to 1 or 2. The case is formed with a support portion that is inserted through the magnetic core and supports the magnetic core, and a core support rib is formed on the outer surface of the support portion, and the magnetic core is The current sensor according to claim 1, wherein the current sensor is supported by the core support rib with a gap from the outer surface of the support portion. The current sensor according to any one of claims 1 to 4, wherein a cross-sectional shape of the detected portion of the bus bar is a U-shape having a pair of upright portions at both end portions.

Images