JP2010048625A - Current sensor manufacturing method and current sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a current sensor manufacturing method and a current sensor which can improve the position accuracy of a magnetoelectric conversion element with respect to the gap of a core in a structure in which the core is formed integrally with a resin case. <P>SOLUTION: The resin case is prepared in which a substrate which has the magnetoelectric conversion element installed on its front side and is formed with a through-hole for optical measurement at a different part from the installation position of the magnetoelectric conversion element and the ring-shaped core having the gap are formed integrally and in which the gap of the core is exposed to the inside of a housing part. The substrate is temporarily positioned and arranged on the core in the housing part so that the magnetoelectric conversion element is positioned at the gap of the core. Under this condition, the positional relationship between the gap and the magnetoelectric conversion element is directly measured optically through the through-hole from the back side of the substrate. In accordance with the measurement result, the position of the substrate is adjusted so that the magnetoelectric conversion element is positioned at nearly the center between both end faces of the core constituting the gap. After this adjustment and a process for fixing the substrate to the resin case, the current sensor is obtained. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a current sensor manufacturing method and a current sensor in which magnetoelectric conversion elements are arranged in a gap of a core.

  Conventionally, for example, as shown in Patent Documents 1 and 2, a current sensor having a structure in which a substrate having a magnetoelectric conversion element mounted on a surface side and a core having a gap is accommodated in a resin case is known.

  In the current sensor disclosed in Patent Document 1, the substrate and the core are housed in this order from the bottom surface side of the housing portion in the housing portion of the current sensor body (resin case) made of synthetic resin.

Moreover, in the current sensor shown in Patent Document 2, the core and the substrate are arranged in this order from the bottom side of the housing portion in the component housing chamber (housing portion) of the case (resin case). In other words, the substrate is arranged on the core with the front surface as an opposing surface, and the Hall element (magnetoelectric conversion element) arranged in the gap is covered with the substrate when viewed from the back side (upper side) of the substrate. ing.
JP 2002-296305 A JP 2006-112957 A

  By the way, as shown in Patent Documents 1 and 2, in a configuration in which a core as a separate member is accommodated in the resin case, the core is generally filled with a potting material such as an epoxy resin and cured. Suppresses misalignment. In this case, it takes several tens of minutes or more to thermally cure the potting material. For example, if the process of fixing the core is a batch type, a large number of high-temperature tanks for thermosetting are required, and it becomes difficult to make the current sensor manufacturing process one continuous production line. Moreover, when using the continuous high temperature furnace in which the line for thermosetting time enters, a production line becomes long and an installation will become large. Moreover, since the resin case accommodates a core as a separate member and requires a space for filling the potting material, it is difficult to reduce the size of the resin case (current sensor).

  On the other hand, by integrally molding the core with the resin case (insert molding), it is possible to simplify the manufacturing process by eliminating the above-described core fixing process and to reduce the size of the current sensor. In this case, since the magnetoelectric conversion element has to be disposed in the gap of the core integrated with the resin case, the surface of the substrate (mounting surface of the magnetoelectric conversion element) faces the opposite surface as in the structure shown in Patent Document 2. Will be placed on the core. That is, when viewed from the back side (upper side) of the substrate, the Hall element arranged in the gap is covered with the substrate. Therefore, the positional relationship between the gap and the magnetoelectric conversion element cannot be confirmed by an optical method such as a camera, and there is a risk that a misalignment of the magnetoelectric conversion element with respect to the core (gap) may occur. Further, the characteristic variation due to the disturbance magnetic field becomes larger as the magnetoelectric conversion element is shifted to one end face side from the center position between both end faces of the core constituting the gap. This point has also been confirmed by the present inventors.

  In view of the above problems, the present invention provides a current sensor manufacturing method and a current sensor that can improve the positional accuracy of the magnetoelectric transducer with respect to the core gap in a configuration in which the core is integrally formed with the resin case. Objective.

  In order to achieve the above object, the current sensor manufacturing method according to claim 1 has a magnetoelectric conversion element mounted on the surface side, and a through hole for optical measurement is formed in a part different from the mounting part of the magnetoelectric conversion element. A substrate preparing step for preparing the prepared substrate, a case preparing step for preparing a resin case in which a ring-shaped core having a gap is integrally formed and the core gap is exposed in the housing portion, and a magnetoelectric transducer in the core gap And temporarily positioning the substrate on the core in the housing so that the substrate is positioned, and in the temporarily positioned state, the positional relationship between the gap and the magnetoelectric transducer is optically determined from the back side of the substrate through the through hole. And adjusting step for adjusting the position of the substrate so that the magnetoelectric conversion element is positioned substantially at the center between both end faces of the core constituting the gap according to the measurement result Characterized by comprising a fixing step of fixing the substrate to the resin case, the.

  According to the present invention, a substrate on which a through hole for optical measurement is formed in a portion different from the mounting portion of the magnetoelectric conversion element is prepared, and the substrate is temporarily positioned on the core in the housing portion, and the back side of the substrate Then, the positional relationship between the gap and the magnetoelectric transducer is directly measured optically through the through hole. At this time, the optical axis of the optical measuring device is not substantially perpendicular to the back surface of the substrate but is oblique. And, the position of the magnetoelectric conversion element due to the positional deviation of the core with respect to the resin case at the time of resin molding (insert molding), the positional deviation of the magnetoelectric conversion element with respect to the substrate, the dimensional variation of the resin case, core, substrate, magnetoelectric conversion element, When the position is shifted toward one end face with respect to the approximate center between both end faces of the core constituting the gap, the position of the substrate is corrected so that the position of the magnetoelectric conversion element is approximately the center. In this way, the position of the substrate is corrected according to the measurement result, and then the substrate is fixed to the resin case. Therefore, the magnetoelectric conversion element is accurately positioned with respect to the gap of the core, and the characteristic fluctuation due to the disturbance magnetic field is consequently reduced. A reduced current sensor can be obtained. In particular, in the present invention, since the positional relationship between the gap and the magnetoelectric conversion element is directly measured, the magnetoelectric conversion element can be positioned with high accuracy with respect to the gap of the core. In addition, when the position of the magnetoelectric conversion element is the approximate center between both end faces of the core constituting the gap as a result of the measurement, it goes without saying that the position is fixed without correction.

  As described in claim 2, in the adjusting step, an interval (gap) between one end face of the core constituting the gap and the magnetoelectric conversion element may be optically measured. According to this, although the variation of the gap (interval between both end faces of the core) is not considered, the magnetoelectric conversion element can be accurately positioned with respect to the gap of the core. In addition, compared to a configuration in which the distance (gap) between the both end faces of the core constituting the gap and the magnetoelectric transducer is optically measured, the ratio of the through-hole occupying the substrate is reduced and the physique of the current sensor is reduced. be able to.

  Next, a method for manufacturing a current sensor according to claim 3 is provided with a substrate in which a magnetoelectric conversion element is mounted on the surface side and a through hole for optical measurement is formed in a portion different from the mounting portion of the magnetoelectric conversion element. A substrate preparation step, a case preparation step of preparing a resin case in which a ring-shaped core having a gap is integrally formed, and the core gap is exposed in the housing portion, and a magnetoelectric conversion element is positioned in the gap of the core In the through hole in the direction along the back surface of the substrate (hereinafter referred to as the horizontal direction) from the back surface side of the substrate in the provisional positioning step in which the substrate is temporarily positioned and disposed on the core in the housing portion. Optically measure at least one of the core and the resin case located in the through hole and the through hole, and at least one reference portion of the core and the resin case is in a predetermined position in the through hole according to the measurement result So as to be an adjustment step of adjusting the position of the substrate, after the adjusting step, a fixing step of fixing the substrate to the resin case, comprising: a.

  In the present invention, the positional relationship between the gap and the magnetoelectric transducer is not directly measured directly through the through hole, but from the back side of the substrate, the through hole, the core positioned in the through hole in the horizontal direction, and the resin case At least one of them is measured optically. At this time, if at least one reference portion of the core and the resin case is deviated from a predetermined position in the through hole, the position of the substrate is adjusted so that the reference portion becomes a predetermined position in the through hole. Thereby, the magnetoelectric conversion element mounted on the substrate can be accurately positioned with respect to the gap of the core integrated with the resin case. In this way, the position of the substrate is corrected according to the measurement result, and then the substrate is fixed to the resin case. Therefore, the magnetoelectric conversion element is accurately positioned with respect to the gap of the core, and the characteristic fluctuation due to the disturbance magnetic field is consequently reduced. A reduced current sensor can be obtained.

  Further, in the present invention, the optical axis of the optical measuring device is substantially perpendicular to the back surface of the substrate, that is, since it can be measured from directly above the through hole, the ratio of the through hole in the substrate is reduced, The physique of the current sensor can also be reduced.

  Specifically, as described in claim 4, in the substrate preparation step, a substrate in which mark marks are formed around the through holes on the back surface is prepared, and in the adjustment step, a core that forms a gap as a reference portion The position of the substrate may be adjusted such that one of the end surfaces of the substrate or the boundary portion between the core and the resin case exposed from the resin case coincides with the mark mark. Further, as described in claim 5, in the case preparation step, a core or a resin case having the same shape as the cross-sectional shape of the through hole and having a positioning mark smaller than the through hole is prepared and adjusted as a reference portion. In the process, the position of the substrate may be adjusted so that the positions of the through hole and the positioning mark match.

  According to a sixth aspect of the present invention, in the case preparation step, a resin case in which a terminal made of a conductive material is integrally formed with the core, one end of the terminal is exposed to the connector portion, and the other end of the terminal is exposed to the housing portion. In the substrate preparation step, a substrate having a first through hole into which a terminal is inserted and a land electrically connected to the magnetoelectric conversion element around the first through hole is prepared. The terminal may be inserted into the first through hole of the substrate, and the terminal and the land may be soldered in the fixing step.

  According to this, a board | substrate can be temporarily positioned on the basis of the edge part side exposed in the accommodating part of a resin case among the terminals which comprise a connector part. Moreover, a board | substrate can be fixed to a resin case via a terminal by solder-joining a terminal and a land after an adjustment process.

  According to the seventh aspect of the present invention, in the substrate preparation step, as the magnetoelectric conversion element, the magnetic sensor chip and the lead are electrically connected, and the magnetic sensor chip and the connection portion between the magnetic sensor chip and the lead are sealed with resin. Using the molded IC, a lead is inserted into the second through hole, and a land formed around the second through hole is soldered to the substrate, and a gap between the first through hole and the terminal is prepared. It is preferable that the gap be larger than the gap between the second through hole and the lead. According to this, the clearance between the first through hole and the terminal can be increased, that is, the substrate position adjustment allowance can be increased.

  Next, according to an eighth aspect of the present invention, a ring-shaped core having a gap is integrally formed with the resin case, and at least a part of the core including the gap is exposed in the housing portion of the resin case, and on the surface side. A substrate on which the magnetoelectric conversion element is mounted is disposed on the core in the housing of the resin case, and the position of the magnetoelectric conversion element is within the gap of the core, and the substrate is mounted on the magnetoelectric conversion element A through hole is provided in a part different from the part, and the through hole is a position where the positional relationship between the gap and the magnetoelectric transducer can be optically directly measured from the back side of the substrate through the through hole. .

  The current sensor according to the present invention is formed on the basis of the invention described in claim 1 (a method for manufacturing a current sensor), and the function and effect thereof are the same as those of the invention described in claim 1. Since there are, description is abbreviate | omitted.

  According to the ninth aspect of the present invention, a ring-shaped core having a gap is integrally formed with the resin case, and at least a part of the core including the gap is exposed in the housing portion of the resin case, and the magnetoelectric surface is provided on the surface side. A current sensor in which the substrate on which the conversion element is mounted is disposed on the core in the housing portion of the resin case and the position of the magnetoelectric conversion element is within the gap of the core, and the substrate is the mounting portion of the magnetoelectric conversion element The through hole is located at a position where at least one of the core and the resin case positioned in the through hole in the horizontal direction can be optically measured together with the through hole from the back side of the substrate. It is characterized by.

  The current sensor according to the present invention is formed on the basis of the invention according to the third aspect (the method for manufacturing the current sensor), and the operational effects thereof are the same as the operational effects of the invention according to the third aspect. Since there are, description is abbreviate | omitted.

  In addition, since the invention of Claim 10 and 11 was each formed based on the invention of Claim 4 and 5, the description is abbreviate | omitted.

  Further, the invention described in claim 12 is formed based on the invention described in claim 7, and its operational effect is the same as the operational effect of the invention described in claim 7. Description is omitted.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The current sensor shown in the present embodiment is suitable as a current sensor for measuring the current of a battery mounted on an automobile.
(First embodiment)
FIG. 1 is a cross-sectional view showing a schematic configuration of a current sensor according to the first embodiment of the present invention. FIG. 2 is a plan view of the current sensor shown in FIG. 1, and the lid is omitted for convenience. FIG. 3 is a perspective view of the current sensor shown in FIG. 1, and the substrate and the lid are omitted for convenience. In the following, the thickness direction of the substrate in the current sensor is defined as the vertical direction, and the direction along the front surface (back surface) of the substrate is defined as the horizontal direction.

  As shown in FIGS. 1 to 3, the current sensor 100 includes, as main parts, a resin case 10, a core 20 having a gap 20 </ b> G, a magnetoelectric conversion element 30, and a substrate 40 on which the magnetoelectric conversion element 30 is mounted. ,have.

  The resin case 10 is formed by molding a resin material into a predetermined shape so as to accommodate the core 20 and the substrate 40, and has at least an accommodating portion 11 that accommodates at least a part of the core 20 including the gap 20G and the substrate 40. It is. In this embodiment, it has the fixing | fixed part 12 and the connector part 13 with the above-mentioned accommodating part 11. As shown in FIG.

  Specifically, the accommodating portion 11 has a substantially rectangular box structure in which the end surface 11a (hereinafter referred to as the upper end surface 11a) on the upper side in the vertical direction is open, and the substrate 40 is disposed as an area inside the box. And the lower region 15 where a part of the core 20 including the gap 20G is exposed. The upper region 14 is a region extending vertically downward from the upper end surface 11a to a predetermined depth, and a part of the bottom portion 14a of the upper region 14 is opened to communicate with the lower region 15 having a predetermined depth. Accordingly, the size in the horizontal direction is smaller in the lower region 15 than in the upper region 14. In addition, the shape of the upper region 14 in the horizontal direction is substantially the same as the outer peripheral shape of the substrate 40, and the size thereof is larger than that of the substrate 40 to the extent that there is no hindrance to substrate position adjustment described later. Then, in a state where the substrate 40 is disposed in the upper region 14, as shown in FIGS. 1 and 2, the exposed region of the core 20 including the lower region 15, that is, the gap 20G, is covered with the substrate 40. ing. In addition, support pins 16 that support the substrate 40 while temporarily positioning the substrate 40 are provided on the bottom portion 14a of the upper region 14. In the present embodiment, the support pin 16 is also configured as a part of the resin case 10 and has an enlarged diameter portion 16a in a predetermined range from the bottom portion 14a side as shown in FIG. Then, with the diameter-enlarged portion 16a coming into contact with the surface 40a of the substrate 40 while being inserted into a through hole (not shown) of the substrate 40, the support pins 16 support the substrate 40 on the bottom portion 14a. . In other words, the substrate 40 is positioned in the vertical direction.

  As shown in FIG. 1, the accommodating portion 11 has a lid 50 fixed to the upper end surface 11 a so as to cover the open surface in a state where the substrate 40 is accommodated in the upper region 14, and the inner regions 14, 15. Is a closed area (space).

  The fixing part 12 is a part for fixing the current sensor 100 to a member to be measured through which a current to be measured flows, and has a through hole 12a through which the member to be measured is inserted. And most of the ring-shaped (substantially C-shaped) core 20 is enclosed in the fixing | fixed part 12 so that the through-hole 12a may be surrounded. The connector part 13 is a part for electrically connecting the magnetoelectric conversion element 30 and an external device via a wiring part (not shown) formed on the substrate 40. One end of a terminal 17 made of metal, for example, integrally formed with the resin case 10 is exposed at the connector portion 13. Note that the other end of the terminal 17 protrudes from the bottom portion 14 a and extends in the vertical direction, and is disposed in the upper region 14 of the accommodating portion 11.

  The core 20 is made of a magnetic material such as iron, an iron-based alloy, and permalloy, and is a ring-shaped member having a gap 20G in which a magnetoelectric conversion element is disposed. Such a core 20 is generally formed by laminating and fixing a plurality of members formed by shearing the magnetic material. In this embodiment, a substantially C-shaped laminated core is employed. As described above, the core 20 is integrally formed with the resin case 10, that is, insert-molded with respect to the resin case 10. Of the substantially C-shaped core 20, only the gap 20 </ b> G and the vicinity of both end faces 21 sandwiching the gap G are exposed in the accommodating portion 11 (lower region 15).

  The magnetoelectric conversion element 30 detects magnetic flux generated by the current to be measured flowing through the member to be measured, and outputs a signal proportional to the current value, and is mounted on the surface 40a side of the substrate 40 to be described later. It is accommodated in the accommodating portion 11 of the resin case 10 and disposed in the gap 20G of the core 20. In the present embodiment, as the magnetoelectric conversion element 30, a magnetic sensor chip 31 and a lead 32 are electrically connected, and the magnetic sensor chip 31 and a connection part between the magnetic sensor chip 31 and the lead 32 are resin-sealed. Is adopted. In the present embodiment, a magnetic sensor chip having a Hall element is employed, and the current sensor 100 is a so-called magnetic proportional current sensor. In addition to the Hall element, a magnetic sensor chip having a magnetoresistive element can also be employed. A portion of the magnetoelectric conversion element 30 that is molded with the sealing resin, that is, the magnetic sensor chip 31 is disposed in the gap 20 </ b> G of the core 20. In the drawing, reference numeral 31 is assigned to the entire resin-sealed portion including the magnetic sensor chip 31 for convenience.

  The substrate 40 is a part for electrically connecting the connector part 13 and the magnetoelectric conversion element 30 configured in the resin case 10, and has a wiring part (not shown) for electrically connecting the magnetoelectric conversion element 30 and the terminal 17. is doing. And it accommodates in the accommodating part 11 (upper area | region 14) of the resin case 10, and is arrange | positioned so that the site | part of the core 20 including the gap 20G exposed in the accommodating part 11 may be covered. Moreover, in this embodiment, it has two types of through-holes 41 and 42 penetrated from the surface 40a facing the core 20 to the back surface 40b. The first through hole 41 is a portion into which the end side exposed in the accommodating portion 11 of the terminal 17 is inserted, and fulfills the function of temporarily positioning the position of the substrate 40 in the horizontal direction. The terminal 17 is solder-bonded to a land of a wiring portion (not shown) in a state where an end portion of the terminal 17 is inserted through the first through hole 41 from the front surface 40a side to the back surface 40b side. The second through hole 42 is a part into which the lead 32 in the magnetoelectric conversion element 30 is inserted. The magnetic sensor chip 31 of the magnetoelectric conversion element 30 is disposed on the front surface 40a side, and is soldered to a land of a wiring portion (not shown) in a state where the lead 32 is inserted from the front surface 40a side to the back surface 40b side. In the present embodiment, in these two types of through holes 41 and 42, the gap (clearance) between the first through hole 41 and the terminal 17 is larger than the gap (clearance) between the second through hole 42 and the lead 32. It has a configuration.

  In addition, the substrate 40 has a through hole 43 (viewing window for optical measurement) at a position different from the mounting portion of the magnetoelectric conversion element 30, that is, at a position away from the connection portion with the lead 32 of the magnetoelectric conversion element 30 in the horizontal direction. )have. This through-hole 43 is a main characteristic part of the current sensor 100 according to the present embodiment. In the present embodiment, the through hole 43 has a substantially circular cross section, and the positional relationship between the gap 20G and the magnetoelectric transducer 30 (magnetic sensor chip 31) is optically determined from the back surface 40b side of the substrate 40 through the through hole 43. It is formed in a position and size that can be directly measured. However, in the horizontal direction, if the cross-sectional area (diameter) of the through hole 43 is constant as the distance from the connection portion with the lead 32 of the magnetoelectric conversion element 30 increases, the size of the upper region 14 of the housing portion 11 must be increased. I must. Further, if the size of the upper region 14 of the accommodating portion 11 is constant, the cross-sectional area of the through hole 43 must be increased as the distance from the connection portion with the lead 32 of the magnetoelectric conversion element 30 increases. Therefore, it is preferable that the formation position of the through-hole 43 is in the vicinity of the connection portion with the lead 32 of the magnetoelectric conversion element 30 as shown in FIG.

  A processing circuit for the magnetoelectric conversion element 30 may be configured on the substrate 40. In the present embodiment, as shown in FIG. 1, an electronic component 44 such as a capacitor or a chip thermistor is mounted on the back surface 40 b of the substrate 40. As described above, when the electronic component 44 is configured such that a temperature sensor element such as a chip thermistor is mounted, a current sensor with a temperature sensor capable of not only current measurement but also temperature measurement can be obtained.

  Next, a method for manufacturing the above-described current sensor 100 will be described. FIG. 4 is a cross-sectional view illustrating a case preparation process in the current sensor manufacturing process. FIG. 5 is a cross-sectional view showing a provisional arrangement process in the current sensor manufacturing process. 6 and 7 are diagrams showing an adjustment process in the manufacturing process of the current sensor, FIG. 6 is a cross-sectional view, and FIG. 7 is a plan view.

  Although not shown in the drawings, first, a substrate preparation step of preparing the substrate 40 in which the magnetoelectric conversion element 30 is mounted on the surface 40a side and the optical measurement through hole 43 is formed in a portion different from the mounting portion of the magnetoelectric conversion element 30 is performed. carry out. In the present embodiment, a substrate 40 is prepared in which the above-described two types of through holes 41 and 42 and a wiring portion (not shown) are formed, and an electronic component 44 different from the magnetoelectric conversion element 30 is mounted. The magnetoelectric conversion element 30 is mounted with the leads 32 inserted through the second through holes 42. In addition, the two types of through holes 41 and 42 are formed so that the clearance (clearance) between the first through hole 41 and the terminal 17 is larger than the clearance (clearance) between the second through hole 42 and the lead 32. Form.

  Also, as shown in FIG. 4, a resin case 10 is prepared in which a ring-shaped core 20 having a gap 20G is integrally formed (insert molding), and the accommodating portion 11 (the gap 20G of the core 20 is exposed in the lower region 15). That is, in this case preparation process, the core 20 is used as an insert part, and the resin case 10 is formed by injection molding, whereby the core 20 is separated from both end faces 21 including the gap 20G. Only the portion is exposed in the accommodating portion 11 (exposed to the upper region 14 side through the bottom portion 14a of the upper region 14), and the other portions are wrapped and surrounded by the resin case 10 for positioning and holding. In the form, the resin case 10 having the above-described accommodating portion 11, fixing portion 12, and connector portion 13 is formed. The terminal 17 made of a conductive material is also integrally formed, and the terminal 17 is held by the resin case 10 with one end exposed at the connector portion 13 and the other end exposed at the housing portion 11 (upper region 14). The

  Next, as shown in FIG. 5, the substrate 40 is temporarily positioned in the housing portion 11 of the resin case 10 so that the magnetoelectric conversion element 30 is positioned in the gap 20 </ b> G of the core 20 and covers the exposed core 20. A temporary placement step for placement is performed. In the present embodiment, the substrate 40 is placed so that the surface 40a faces the core 20, the terminal 17 is inserted through the first through hole 41, and the support pin 16 (see FIGS. 2 and 3) is inserted through the through hole (not shown). It arrange | positions in the upper area | region 14 of the accommodating part 11. As shown in FIG. Here, the clearance (clearance) between the first through hole 41 and the terminal 17 and the clearance (clearance) between the through hole and the support pin 16 are approximately the same, and the horizontal direction is determined by the terminal 17 and the support pin 16. The position of the substrate 40 is temporarily positioned. Further, the surface 40a of the substrate 40 abuts on the enlarged diameter portions 16a (see FIG. 3) of the plurality of support pins 16, and thereby the position of the substrate 40 is determined in the vertical direction. In this embodiment, in order to further reduce the rattling of the substrate 40 in the vertical direction, the magnetoelectric conversion element 30 (molded magnetic sensor chip 31) is in the contact state as shown in FIG. It comes into contact with the bottom of the lower region 15.

  Here, in order to detect the current to be measured with high accuracy by the current sensor 100, the magnetoelectric conversion element 30 (magnetic sensor chip 31) is positioned at substantially the center (in other words, between both end faces 21 of the core 20 constituting the gap 20G). For example, it is preferable to dispose at approximately the center of the gap 20G. However, the dimensional variation of the resin case 10, the core 20, the substrate 40, and the magnetoelectric conversion element 30, the dimensional variation and the formation position of the first through hole 41 and the second through hole 42, the core 20 relative to the resin case 10 at the time of insert molding, The position of the magnetoelectric conversion element 30 does not become substantially the center between the both end faces 21 due to the positional deviation (positional variation) of the terminal 17 and the positional variation of the magnetoelectric conversion element 30 mounted on the substrate 40, for example, as shown in FIG. Thus, it can be considered that the arrangement is shifted to the one end face 21 side.

  Therefore, in the present embodiment, the positional relationship between the gap 20G and the magnetoelectric transducer 30 (magnetic sensor chip 31) from the back surface 40b side of the substrate 40 through the through hole 43 as shown in FIG. Measure directly optically. Then, as a result of the measurement, as shown in FIG. 6, when the magnetoelectric conversion element 30 is misaligned, the substrate is arranged so that the magnetoelectric conversion element 30 is positioned approximately at the center between both end faces 21 of the core 20. Adjust the position. This adjustment process is a main characteristic part of the manufacturing method according to the present embodiment.

  In the present embodiment, the optical axis is used so that at least one of the end surface 21 of the core 20 and the magnetoelectric conversion element 30 (magnetic sensor chip 31) are within the imaging area through the through-hole 43 using the camera 110 as an optical measuring device. Is imaged from the back surface 40b side of the substrate 40 in an oblique direction with respect to the vertical and horizontal directions. More specifically, imaging was performed so that only one of the end surfaces 21 of the core 20 was within the imaging area. And based on the imaging result, the position of the board | substrate 40 was corrected as needed. For example, as shown in FIG. 6, the magnetoelectric conversion element 30 is shifted to the left end face 21 side as viewed in the drawing, and as shown in FIG. 7, the gap between the end face 21 and the magnetoelectric conversion element 30 (solid line in FIG. 7) is a distance. Suppose that it was D1. In this case, the distance of the gap between the end face 21 and the magnetoelectric conversion element 30 (broken line in FIG. 7) is the distance D2 when the magnetoelectric conversion element 30 is positioned approximately at the center between the both end faces 21 of the core 20. The substrate 40 is shifted in the direction of the white arrow shown in FIG. 7, and the magnetoelectric transducer 30 is moved in the same direction. In the present embodiment, since the through hole through which the support pin 16 is inserted and the first through hole 41 through which the terminal 17 is inserted have a predetermined clearance between the support pin 16 and the terminal 17, The position can be adjusted by moving 40 in the horizontal direction. The optical measurement may be performed continuously until the position adjustment is completed, or measured every time the position is finely corrected before the position adjustment, after the position adjustment, and finally until the position adjustment is completed ( (Measurement at a predetermined timing).

  Next, after the adjusting step, although not shown, a fixing step for fixing the substrate 40 to the resin case 10 is performed. In this embodiment, the board | substrate 40 is fixed to the resin case 10 via the terminal 17 by solder-joining the several terminal 17 which penetrates the 1st through-hole 41, and a corresponding land. As a result, the magnetoelectric conversion element 30 is positioned and fixed substantially at the center of the both end faces 21 of the core 20. Then, the current sensor 100 shown in FIG. 1 can be obtained by placing the lid 50 (not shown) on the upper end surface 11a of the housing portion 11 of the resin case 10 and fixing it by adhesion or welding.

  Next, the manufacturing method of the current sensor 100 according to the present embodiment and the effects of the characteristic portions of the current sensor 100 formed by this manufacturing method will be described. First, in the present embodiment, a substrate 40 in which a through hole 43 for optical measurement is formed in a portion different from the mounting portion of the magnetoelectric conversion element 30 is prepared, and the substrate 40 is exposed in the housing portion 11 of the resin case 10. The positional relationship between the gap 20 </ b> G and the magnetoelectric transducer 30 is optically directly measured from the back surface 40 b side of the substrate 40 through the through-hole 43 in a state of being temporarily positioned on the core 20. When the position of the magnetoelectric conversion element 30 is shifted to the one end face 21 side with respect to the approximate center between the both end faces 21 of the core 20 constituting the gap 20G, the position of the magnetoelectric conversion element 30 is approximately the center. The position of the substrate 40 is corrected so that As described above, based on the measurement result, the position of the substrate 40 is corrected as necessary, and then the substrate 40 is fixed to the resin case 10, so that the magnetoelectric conversion element 30 is accurate with respect to the gap 20 </ b> G of the core 20. It is possible to obtain the current sensor 100 which is positioned and consequently has a reduced characteristic variation due to a disturbance magnetic field. Further, the obtained current sensor 100 is a current sensor in which the magnetoelectric conversion element 30 is accurately positioned with respect to the gap 20G, and the characteristic variation due to the disturbance magnetic field is reduced. In particular, in the present embodiment, since the positional relationship between the gap 20G and the magnetoelectric conversion element 30 is directly measured, the magnetoelectric conversion element 30 can be positioned with high accuracy with respect to the gap 20G of the core 20.

  In addition, this inventor has confirmed about the relationship between the position of the magnetoelectric conversion element 30 with respect to the gap 20G, and the characteristic fluctuation | variation by a disturbance magnetic field (disturbance noise). FIG. 8 is a plan view schematically showing the relationship between the position of the magnetoelectric transducer and the disturbance magnetic field with respect to the gap of the core. FIG. 9 is a diagram showing the relationship between the positional deviation of the magnetoelectric transducer and the error current generated by the disturbance magnetic field. As shown in FIG. 8, a disturbance magnetic field of 2.0 mT acts along the horizontal direction and in a direction substantially perpendicular to the direction of the magnetic flux acting between the end faces 21. As a result, it is apparent from FIG. 9 that the error current increases, that is, the characteristic variation increases as the magnetoelectric conversion element 30 is displaced from the center position of the both end faces 21 of the core 20. Therefore, according to the present embodiment, since the magnetoelectric conversion element 30 is accurately positioned with respect to the gap 20G of the core 20, the current sensor 100 in which the characteristic fluctuation due to the disturbance magnetic field is reduced can be obtained.

  In the present embodiment, in the adjustment step, the interval (gap) between one end surface 21 of the core 20 constituting the gap 20G and the magnetoelectric conversion element 30 is optically measured. Therefore, the proportion of the through-holes 43 in the substrate 40 is reduced compared to the configuration in which the distance (gap) between both the end faces 21 of the core 20 and the magnetoelectric conversion element 30 is optically measured, and the physique of the current sensor 100 is reduced. Can be reduced.

  In the present embodiment, the clearance (clearance) between the terminal 17 constituting the connector portion 13 and the first through hole 41 through which the terminal 17 is inserted is inserted between the lead 32 of the magnetoelectric conversion element 30 and the lead 32. It is larger than the gap (clearance) with the second through hole 42 to be made. According to this, the clearance between the first through hole 41 and the terminal 17 can be increased, that is, the position adjustment margin of the substrate 40 can be increased.

(Second Embodiment)
Next, 2nd Embodiment of this invention is described based on FIG.10 and FIG.11. 10 and 11 are diagrams showing an adjustment process among the manufacturing processes of the current sensor according to the second embodiment. FIG. 10 is a cross-sectional view, and FIG. 11 is a plan view.

  The current sensor manufacturing method according to the second embodiment and the current sensor formed by the current sensor are often in common with the current sensor manufacturing method and the current sensor shown in the first embodiment. The explanation is omitted, and different parts are explained mainly. In addition, the same code | symbol shall be provided to the element same as the element shown in 1st Embodiment.

  In the first embodiment, the positional relationship between the gap 20G and the magnetoelectric conversion element 30 is directly measured optically. In other words, imaging is performed so that at least one of the end face 21 of the core 20 and the magnetoelectric conversion element 30 fall within the imaging area, and the position of the magnetoelectric conversion element 30 in the gap 20G is determined from the interval between the end face 21 and the magnetoelectric conversion element 30. I tried to figure out. On the other hand, in the present embodiment, when the through hole 43 and at least one of the core 20 and the resin case 10 positioned in the through hole 43 in the horizontal direction are optically measured and a positional deviation occurs, The position of the substrate 40 is adjusted so that at least one reference portion of the core 20 and the resin case 10 is a predetermined position in the through hole 43. That is, instead of directly measuring the positional relationship between the gap 20G and the magnetoelectric conversion element 30, at least one of the core 20 having the gap 20G and the resin case 10 integrally formed with the core 20 and the magnetoelectric conversion element 30 are mounted. It is characterized in that the position of the magnetoelectric transducer 30 in the gap 20G is grasped by directly measuring the through hole 43 of the substrate 40.

  The structure of the current sensor 100 according to this embodiment is basically the same as that of the current sensor 100 (see FIGS. 1 to 3) shown in the first embodiment. The first difference is that the formation position of the through hole 43 is the core 20 (within the accommodating portion 11) located in the horizontal direction along with the through hole 43 from the back surface 40 b side of the substrate 40 in the adjustment step. ) And at least one of the resin case 10 (the bottom portion 14a of the upper region 14 in the accommodating portion 11) is a position where it can be optically measured. Secondly, as shown in FIGS. 10 and 11, as the reference portion, a positioning mark 22 having the same shape as the cross-sectional shape of the through hole 43 and smaller than the through hole 43 is formed on the upper surface ( This is a point provided on the surface 40a of the substrate 40 facing the surface 40a. The shape of the positioning mark 22 (the shape of the through hole 43) and the method for forming the positioning mark 22 are not particularly limited. As the positioning mark 22, any optical mark that can be used as a position reference can be used. In the present embodiment, a positioning mark 22 having a substantially circular plane is provided on the upper surface of the core 20 by printing.

  Next, the adjustment process which is a characteristic part in the manufacturing method of the current sensor 100 according to the present embodiment will be described. The substrate preparation process, case preparation process, provisional arrangement process, and fixing process are basically the same as those in the first embodiment. In the adjustment step, in the temporarily positioned state, as shown in FIG. 10, from the back surface 40 b side of the substrate 40, at least one of the through hole 43 and the core 20 and the resin case 10 positioned in the through hole 43 in the horizontal direction. Are measured optically. As a result of the measurement, as shown in FIG. 10, when at least one reference portion (the positioning mark 22 in FIG. 10) of the core 20 and the resin case 10 is not in a predetermined position in the through hole 43, the magnetoelectric conversion element The position of the substrate 40 is adjusted so that the reference portion is located at a predetermined position in the through-hole 43, assuming that the positional deviation occurs at 30. As a result, the position of the magnetoelectric conversion element 30 is substantially the center between the both end faces 21 of the core 20.

  In the present embodiment, a camera 110 as an optical measuring device is used, and imaging is performed from the back surface 40b side of the substrate 40 along the optical axis so that the through hole 43 is in the imaging area. Specifically, a part of the back surface 40b of the substrate 40 including the through hole 43 (open end of the substrate 40), an exposed part of the core 20 located below the substrate 40 and positioned in the through hole 43 in the horizontal direction, and The bottom part 14a of the accommodating part 11 in the resin case 10 is imaged. And based on the imaging result, the position of the board | substrate 40 was corrected as needed. For example, as shown in FIG. 10, the position of the positioning mark 22 as a reference portion is shifted to the right side with respect to the paper surface with respect to the center of the through-hole 43, and as shown in FIG. 11, the positioning mark 22 (solid line in FIG. 11). ) Is only located in the through hole 43. At this time, as shown in FIG. 10, the magnetoelectric conversion element 30 (magnetic sensor chip 31) is also shifted to the left from the approximate center of the both end surfaces 21 of the core 20 toward the paper surface. Is substantially equal to the amount of displacement of the positioning mark 22 with respect to. Therefore, by shifting the substrate 40 in the direction of the white arrow shown in FIG. 11 so that the positioning mark 22 (broken line in FIG. 11) overlaps the center of the through hole 43, the position of the magnetoelectric conversion element 30 is changed to the core. It can be set at the approximate center of the two end faces 21 of 20.

  As described above, also by the manufacturing method shown in the present embodiment, the current sensor 100 in which the magnetoelectric conversion element 30 is accurately positioned with respect to the gap 20G of the core 20 and the characteristic fluctuation due to the disturbance magnetic field is reduced can be obtained. . Further, the obtained current sensor 100 is a current sensor in which the magnetoelectric conversion element 30 is accurately positioned with respect to the gap 20G, and the characteristic variation due to the disturbance magnetic field is reduced.

  Further, according to the present embodiment, instead of the gap 20G and the magnetoelectric conversion element 30, the through hole 43 (open end of the substrate 40) and at least one reference portion of the resin case 10 and the core 20 are aligned. As described above, the optical axis of the camera 110 may be substantially perpendicular to the back surface 40b of the substrate 40, and measurement may be performed from directly above the through hole 43. Therefore, compared with the structure shown in 1st Embodiment, the ratio of the through-hole 43 which occupies for the board | substrate 40 can be made small, and the physique of the current sensor 100 can also be reduced.

  In the present embodiment, the example in which the positioning mark 22 as the reference portion is provided on the upper surface of the core 20 is shown. However, the positioning mark 22 may be provided not on the core 20 but on the resin case 10 (the bottom 14a of the upper region 14). In addition, a portion other than the positioning mark 22 can be used as a reference portion. For example, the substrate 40 in which the mark mark 45 is formed around the through hole 43 on the back surface 40b is prepared, and in the adjustment process, as shown in FIG. 12, the exposed portion (upper surface) of the core 20 and the resin case 10 (upper region 14). Even if the position of the substrate 40 is adjusted so that the mark mark 45 and the boundary part coincide with each other using the opening end of the bottom part 14a in the resin case 10 as a reference part. good. FIG. 12 is a plan view showing a modification of the adjustment process. In the example shown in FIG. 12, two mark marks 45 of a plane triangle are arranged opposite to each other with the apex at the side of the through hole 43 and sandwiching the through hole 43. In addition to the boundary part, one of the end faces 21 of the core 20 can be adopted as such a reference part.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

It is sectional drawing which shows schematic structure of the current sensor which concerns on 1st Embodiment. It is a top view of the current sensor shown in FIG. It is a perspective view of the current sensor shown in FIG. It is sectional drawing which shows a case preparation process among the manufacturing processes of an electric current sensor. It is sectional drawing which shows a temporary arrangement | positioning process among the manufacturing processes of an electric current sensor. It is sectional drawing which shows an adjustment process among the manufacturing processes of a current sensor. It is a top view which shows an adjustment process among the manufacturing processes of a current sensor. It is the top view which showed typically the relationship between the position of the magnetoelectric conversion element with respect to the gap of a core, and a disturbance magnetic field. It is a figure which shows the relationship between the position shift of a magnetoelectric conversion element, and the error electric current produced by a disturbance magnetic field. It is sectional drawing which shows an adjustment process among the manufacturing processes of the current sensor which concerns on 2nd Embodiment. It is a top view which shows an adjustment process among the manufacturing processes of a current sensor. It is a top view which shows the modification of an adjustment process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Resin case 11 ... Accommodating part 17 ... Terminal 20 ... Core 20G ... Gap 21 ... End surface 30 ... Magnetoelectric conversion element 32 ... Lead 40 ... Substrate 40a ... front surface 40b ... back surface 41 ... first through hole 42 ... second through hole 43 ... through hole 100 ... current sensor

Claims (12)

A substrate preparation step of preparing a substrate on which a magnetoelectric conversion element is mounted on the surface side, and a through hole for optical measurement is formed in a portion different from the mounting portion of the magnetoelectric conversion element;
A case preparation step of preparing a resin case in which a ring-shaped core having a gap is integrally formed and the gap of the core is exposed in the housing portion;
A temporary placement step of temporarily positioning and placing the substrate on the core in the housing portion so that the magnetoelectric conversion element is positioned in the gap of the core;
In the temporarily positioned state, the positional relationship between the gap and the magnetoelectric conversion element is optically directly measured from the back side of the substrate through the through hole, and the magnetoelectric conversion element reduces the gap according to the measurement result. An adjustment step of adjusting the position of the substrate so as to be positioned at substantially the center between both end faces of the core to be configured;
After the said adjustment process, the fixing process which fixes the said board | substrate to the said resin case is provided, The manufacturing method of the current sensor characterized by the above-mentioned.   2. The method of manufacturing a current sensor according to claim 1, wherein, in the adjustment step, an interval between one end face of the core constituting the gap and the magnetoelectric conversion element is optically measured. A substrate preparation step of preparing a substrate on which a magnetoelectric conversion element is mounted on the surface side, and a through hole for optical measurement is formed in a portion different from the mounting portion of the magnetoelectric conversion element;
A case preparation step of preparing a resin case in which a ring-shaped core having a gap is integrally formed and the gap of the core is exposed in the housing portion;
A temporary placement step of temporarily positioning and placing the substrate on the core in the housing portion so that the magnetoelectric conversion element is positioned in the gap of the core;
In the temporarily positioned state, from the back surface side of the substrate, at least one of the core and the resin case positioned in the through hole in a direction along the back surface of the substrate, and the through hole are optically measured. An adjustment step of adjusting the position of the substrate so that at least one reference portion of the core and the resin case is in a predetermined position in the through hole according to a measurement result;
After the said adjustment process, the fixing process which fixes the said board | substrate to the said resin case is provided, The manufacturing method of the current sensor characterized by the above-mentioned. In the substrate preparation step, preparing the substrate on which a mark is formed around the through hole on the back surface,
In the adjustment step, one of end surfaces of the core constituting the gap as the reference portion or a boundary portion between the core and the resin case exposed from the resin case is matched with the mark. The method of manufacturing a current sensor according to claim 3, wherein the position of the substrate is adjusted. In the case preparation step, as the reference portion, the core or the resin case having the same shape as the cross-sectional shape of the through hole and having a positioning mark smaller than the through hole is prepared,
The method of manufacturing a current sensor according to claim 3, wherein, in the adjustment step, the position of the substrate is adjusted so that the positions of the through holes and the positioning marks are aligned. In the case preparing step, a terminal made of a conductive material is integrally formed with the core, one end of the terminal is exposed to the connector portion, and the other end of the terminal is exposed to the housing portion to prepare the resin case,
In the substrate preparation step, the first through hole into which the terminal is inserted and the substrate on which the land electrically connected to the magnetoelectric conversion element is formed around the first through hole are prepared,
In the temporary placement step, the terminal is inserted into the first through hole of the substrate,
6. The method of manufacturing a current sensor according to claim 1, wherein, in the fixing step, the terminal and the land are joined by soldering. In the substrate preparation step, as the magnetoelectric conversion element, a magnetic sensor chip and a lead are electrically connected, and the magnetic sensor chip and a mold IC in which a connection portion between the magnetic sensor chip and the lead is sealed with a resin Using the substrate, wherein the lead is inserted into a second through hole and soldered to a land formed around the second through hole;
The method for manufacturing a current sensor according to claim 6, wherein a gap between the first through hole and the terminal is larger than a gap between the second through hole and the lead. A substrate in which a ring-shaped core having a gap is integrally formed with a resin case, at least a part of the core including the gap is exposed in a housing portion of the resin case, and a magnetoelectric conversion element is mounted on the surface side. A current sensor disposed on the core in the housing portion of the resin case, wherein the position of the magnetoelectric transducer is within the gap of the core,
The substrate has a through hole in a portion different from the mounting portion of the magnetoelectric conversion element, and the through hole optically determines the positional relationship between the gap and the magnetoelectric conversion element through the through hole from the back surface side of the substrate. A current sensor characterized in that the position can be directly measured. A substrate in which a ring-shaped core having a gap is integrally formed with a resin case, at least a part of the core including the gap is exposed in a housing portion of the resin case, and a magnetoelectric conversion element is mounted on the surface side. A current sensor disposed on the core in the housing portion of the resin case, wherein the position of the magnetoelectric transducer is within the gap of the core,
The substrate has a through hole in a portion different from the mounting portion of the magnetoelectric conversion element, and the through hole extends from the back surface side of the substrate along with the through hole in a direction along the back surface of the substrate. A current sensor characterized in that at least one of the core and the resin case located inside can be optically measured. The substrate has a mark around the through hole on the back surface,
10. One of end faces of the core constituting the gap, or a boundary portion between the core and the resin case exposed from the resin case is aligned with the mark. The current sensor described. One of the resin case and the core exposed in the housing portion of the resin case has the same shape as the cross-sectional shape of the through hole and a positioning mark smaller than the through hole,
The current sensor according to claim 9, wherein the through hole and the positioning mark are aligned. In the resin case, a terminal made of a conductive material is integrally formed with the core, one end of the terminal is exposed to the connector portion of the resin case, and the other end of the terminal is exposed in the housing portion,
As the magnetoelectric conversion element, a magnetic sensor chip and a lead are electrically connected, and the magnetic sensor chip and a molded IC in which a connection portion between the magnetic sensor chip and the lead is sealed with resin are used.
The substrate includes a first through hole in which the terminal is inserted, a land provided around the first through hole, electrically connected to the magnetoelectric conversion element and solder-bonded to the terminal, and the lead A second through hole in which is inserted, and a land provided around the second through hole and soldered to the lead,
The current sensor according to claim 8, wherein a gap between the first through hole and the terminal is larger than a gap between the second through hole and the lead.

Images