JP2009025115A - Current sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a current sensor which prevents an external stress from being given to a joining part of a terminal after a coil terminal portion is tied around it and soldered, and thus ensures the quality of joining of the soldered part. <P>SOLUTION: The current sensor has the L-shaped terminal 5. The L-shaped terminal 5 has a long-side end portion 5b to be made to penetrate an exterior case 4, as an implementing part, and a short-side end portion 5c to be tied with opposite terminal portions of a coil and soldered for joining, and these end portions are formed separately and independently of each other, so as to avoid the external stress on the soldered part. Besides, a crushed portion 5a for a penetration stopper is formed on the long-side end portion 5b so as to prevent the sensor from coming into contact with the coil and damaging a wire rod. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a through-hole type current sensor mounted on an electronic device, an earth leakage breaker, or the like.

  A current sensor is a component that is used to detect the current flowing through an electronic device and prevent the device from being damaged or malfunctioning due to an abnormal current. Pass the wire cable on the wiring circuit through the central opening of the current sensor. The magnetic field induced by the abnormal current flowing through the power cable is detected by a coil wound around the core, converted into a voltage signal, and transmitted to the feedback control system.

  13 to 16 are diagrams illustrating a conventional current sensor. The current sensor includes a core 1, a core case 2, a current detection coil 3 wound around the core case 2, an I-shaped terminal 8 that electrically joins the terminal portions of the coil 3, and a central opening portion. It is comprised by the exterior case 4 which has 4a, and the mold resin 6 with which the exterior case 4 was filled. The core 1 is made of a high-permeability permalloy material or the like, and is housed in the core case 2 in a laminated structure in which a plurality of thin plate cores punched in an annular shape are stacked.

FIG. 13 (a) is an external view of the laminated core, FIG. 13 (b) is an external view of the core case, and FIG. 13 (c) is an external view of the coil. FIG. 13D is an external view of the I-shaped terminal, FIGS. 13E and 13F are a cross-sectional view and a front view of the outer case, The state which inserted the character-shaped terminal in the exterior case 4 which has the center opening part 4a is each shown.
FIGS. 14A and 14B are a cross-sectional view and a front view of the outer case after the coil is stored, and the coil wound around the core case in which the core is stored almost evenly is stored in the outer case. Then, the two terminal portions of the coil are respectively shown in a state where they are wound and soldered to one end portion of an I-shaped terminal that has been previously penetrated through the exterior case.
FIG. 15A is a cross-sectional view of the outer case at the time of terminal push-bending. FIG. 15A shows a state where the soldering portion 8a of the I-shaped terminal is pushed and bent into a substantially L shape by using a push jig 7. 15 (b) and FIG. 15 (c) are a cross-sectional view and a front view of the outer case after the terminal is bent, and the state where the I-shaped terminal is pushed and bent into a substantially L shape and is accommodated within the height of the outer case, respectively. Show.
16A and 16B are a cross-sectional view and a front view of the exterior case after resin molding, in which the mold resin 6 is almost completely filled in the exterior case 4 for insulation reinforcement and fixing between the components. Each filled state is shown.
Such a current sensor is disclosed as, for example, the prior art of Patent Document 1.

Japanese Patent Laid-Open No. 11-121259

  In the conventional current sensor, after the terminal portion of the coil 3 is tangled to the I-shaped terminal 8 and soldered, the I-shaped terminal 8 is pushed and bent by using a bending jig 7 or the like, so that the soldering portion 8a is fixed. Stress was applied, and cracks and scratches were generated in the wire material and solder of the soldering portion 8a, and the quality of the joint portion was impaired.

  In addition, when the bending jig 7 or the like comes into contact with the wire of the coil 3 or is pressed and applied with stress, the insulation film of the wire is damaged, causing a short-circuit defect, or in the worst case, the wire As a result, the conductor was damaged and a disconnection failure occurred.

  Furthermore, since lead-free solder due to recent lead-free soldering has increased hardness and becomes brittle compared to conventional leaded solder, there is a concern that the welded solder portion is likely to crack due to external stress.

  In addition, since it is very difficult to confirm and judge the degree of joining such as cracks and damage of the soldered part by in-process inspection, it was often found as a defect for the first time during actual operation in the market. . Therefore, in order to ensure and maintain the solder joint quality, it is indispensable to take measures to prevent stress on the soldered portion.

  Accordingly, an object of the present invention is to provide a current sensor that ensures the bonding quality of a solder joint without applying external stress to the joint after soldering and soldering of the coil terminal.

  In order to solve these problems, the present invention has a terminal having an L shape, one side of the two sides to be bent is passed through the outer case as a mounting portion, and the other is solder for electrically coupling the terminal portion of the coil Each is separated and made independent as a joint, and external stress on the solder joint is avoided. Note that the length of the two sides of the L-shaped terminal that bend is made longer than the solder joint. Therefore, hereinafter, the mounting portion is also called a long side terminal, and the solder joint portion is also called a short side terminal. The L-shaped terminal that penetrates the outer case is placed in the outer case without touching / pressing the coil by sandwiching the vicinity of the bent part of the two sides with finger pressure or a simple jig so as not to touch the solder joint. Therefore, it is possible to avoid problems such as cracks in the welded solder due to external stress. Furthermore, by forming a crushing portion that serves as an insertion stopper when the terminal is pushed into the long side terminal of the L-shaped terminal, it is possible to reliably prevent contact and pressing against the coil. Further, the L-shaped terminal is fixed by filling the outer case with mold resin.

  By configuring in this way, external stress on the short side terminal to bend and solder is reduced to ensure the quality of the solder joint, and the contact / pressing stress to the coil is eliminated, and wire damage and Defects such as disconnection can be reduced, and the quality of the current sensor can be improved.

  According to the present invention, a core made of a high magnetic permeability material, a core case that houses the core, a coil wound around the core case, a terminal that electrically connects a terminal portion of the coil, and an exterior case The terminal is L-shaped, and the current sensor is obtained by penetrating one side of the two bent sides of the L-shape into the exterior case. .

  According to the present invention, it is possible to obtain a current sensor characterized in that a crushed portion is formed on one side of the two bent sides of the L-shape.

  According to the present invention, there is obtained a current sensor characterized in that the L-shaped bent side of the two sides to the exterior case may be either perpendicular or horizontal to the bottom surface of the exterior case. It is done.

  According to the present invention, it is possible to ensure solder joint quality, reduce rare short-circuit defects and disconnection defects, which are typical factors that impair the function of the current sensor, and improve product quality and yield.

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

FIGS. 1-8 is a figure explaining the current sensor of this invention, and shows the case where the L-shaped terminal penetrated perpendicularly | vertically with respect to the bottom face 4c of an exterior case.
FIG. 1A is an external view of an L-shaped terminal and shows that it is composed of a short-side terminal 5c, a long-side terminal 5b, and a crushed portion 5a formed on the long-side terminal 5b. 1 (b) and 1 (c) are a cross-sectional view and a front view of the exterior case, respectively, showing a state in which the long side terminal 5b of the L-shaped terminal 5 has penetrated the exterior case 4 having the central opening 4a. .
2 (a) and 2 (b) are a sectional view and a front view of the outer case after the coil is housed and soldered, and is wound almost uniformly on the entire circumference of the core case 2 in which the core 1 is housed. The state immediately after the coil 3 is housed in the outer case 4 and both end portions of the coil 3 are soldered by being tangled to the tip of the short-side terminal 5c of the L-shaped terminal 5 penetrating the outer case 4 is shown. Each is shown.
3 (a) and 3 (b) are a cross-sectional view and a front view of the outer case after the L-shaped terminal is rotated, and the short-side terminal 5c is arranged around the long-side terminal 5b of the L-shaped terminal 5 as a rotation axis. The state rotated about 90 degree | times inside the exterior case 4 is each shown.
4 (a) and 4 (b) are a cross-sectional view and a front view of the outer case after further pushing the L-shaped terminal, and further pushing the long side terminal 5b of the L-shaped terminal 5 and the short side terminal 5c. Each state stored in the case is shown.
FIGS. 5A and 5B are a cross-sectional view and a front view, respectively, of the exterior case in which a resin is molded in the exterior case.
6 (a) and 6 (b) are a cross-sectional view and a front view of the outer case after the L-shaped terminal is rotated, and the short-side terminal 5c is used with the long-side terminal 5b of the L-shaped terminal 5 as a rotation axis. The state rotated about 180 degree | times inside the exterior case 4 is each shown.
7 (a) and 7 (b) are a sectional view and a front view of the exterior case after further pushing the L-shaped terminal, further pushing the long side terminal 5b of the L-shaped terminal 5 and the short side terminal 5c being packaged. Each state stored in the case is shown.
FIGS. 8A and 8B are a cross-sectional view and a front view, respectively, of the exterior case in which a resin is molded in the exterior case.

As shown in FIG. 1B and FIG. 1C, the L-shaped terminal 5 has the short-side terminal 5 c with the distal end portion positioned outside the outer case 4 and the short-side terminal 5 c being the outer case 4. The long side terminal 5b is penetrated in the perpendicular direction to the bottom surface 4c of the outer case 4 in a state where the insertion is stopped by contacting the upper surface 4b of the outer wall portion.
Thereafter, as shown in FIGS. 2 (a) and 2 (b), after the coil 3 wound almost uniformly on the entire circumference on the core case 2 in which the core 1 is accommodated is accommodated in the outer case 4, the coil The two terminal portions 3 are tangled and soldered to the distal end portion of the short-side terminal 5 c of the L-shaped terminal 5.
Thereafter, as will be described in detail in the following paragraphs, the L-shaped terminal 5 is rotated and pushed in, but at this time, it can be performed without contacting the short-side terminal 5c or the soldered portion, as shown in FIG. At the stage where the L-shaped terminal 5 as shown in FIG. 2 is inserted, the distal end portion of the long-side terminal 5b may be further bent into an L-shape, rotated while pressing this portion, and pulled in. However, since this L-shaped tip is a terminal part for mounting on a board, it is cut again later to make it straight.

  After that, as shown in FIGS. 3A, 3B, 6A, and 6B, the short-side terminal 5c of the L-shaped terminal 5 does not contact the coil 3. It is rotated to a predetermined position by finger pressure or a jig so as to be accommodated in the outer case 4. 3 (a) and 3 (b) show the case where it is rotated about 90 degrees inward, and FIGS. 6 (a) and 6 (b) show the case where it is rotated about 180 degrees inward.

  Subsequently, as shown in FIGS. 4 (a), 4 (b), 7 (a), and 7 (b), a pushing jig or the like is applied to the right-angled portion of the L-shaped terminal 5 so that the longitudinal terminal 5b is further pushed into the outer case 4. At that time, the crushing portion 5a on the long side terminal 5b is prevented from being pushed in, and structurally preventing the wire material of the coil 3 from being damaged by contact and pressing of the short side terminal 5c to the coil 3 due to excessive pushing. it can.

Further, as shown in FIGS. 5 (a), 5 (b), 8 (a), and 8 (b), a mold resin 6 for insulation and fixation is injected and filled into the outer case 4. . In addition, the mold resin 6 serves not only for the purpose of insulation and fixation described above, but also serves as an external stress buffer for the soldered portion on the short-side terminal 5c.
It should be noted that the length of the long terminal 5b of the L-shaped terminal 5 protruding from the outer case 4 may be appropriately adjusted so as to be a constant length by a terminal cutting jig or the like in a subsequent process.

9-12 is a figure explaining the current sensor of this invention, and shows the case where the L-shaped terminal 5 penetrates the bottom face 4c of the exterior case 4 in the horizontal direction.
FIG. 9A is an external view of an L-shaped terminal, and shows that it is composed of a short-side terminal 5c, a long-side terminal 5b, and a crushed portion 5a formed on the long-side terminal 5b. FIGS. 9B and 9C are a cross-sectional view and a front view of the exterior case, respectively, showing a state in which the long-side terminal 5b of the L-shaped terminal 5 has penetrated the exterior case 4 having the central opening 4a. .
FIGS. 10A and 10B are a cross-sectional view and a front view of the outer case after the coil is housed and soldered, and the whole case is wound almost uniformly on the core case 2 in which the core 1 is housed. The state immediately after the coil 3 is housed in the outer case 4 and both end portions of the coil 3 are soldered by being tangled to the tip of the short-side terminal 5c of the L-shaped terminal 5 penetrating the outer case 4 is shown. Each is shown.
11 (a) and 11 (b) are a cross-sectional view and a front view of the outer case after the L-shaped terminal is rotated, and the short-side terminal 5c is arranged around the long-side terminal 5b of the L-shaped terminal 5 as a rotation axis. Each of the states rotated and housed in the outer case 4 is shown.
FIG. 12A and FIG. 12B are a cross-sectional view and a front view of the exterior case after resin molding, respectively, showing a state in which the exterior case 4 is resin-molded.

  The core 1 is made of permalloy having a high permeability material, but may be an alloy such as ferrite or amorphous. Also, it is preferable that a plurality of thin sheet cores each having an annular shape are stacked, and the thickness and the number of layers are suitably adjusted according to the required characteristic conditions.

  The core case 2 is made of an epoxy thermosetting resin, but may be of any material and form as long as it covers the core 1 in an insulating manner, and may be a nylon thermoplastic resin. In addition, the present invention is not limited to the molded body, and an insulating form in which a large number of insulating paper or the like is wound around the core 1 to a certain thickness may be used.

  In the coil 3, an enameled copper wire obtained by baking a natural resin or a synthetic resin paint on a conductor is wound almost uniformly around the entire circumference of the core case 2. The coil wire diameter and the number of turns are appropriately designed and adjusted according to the magnitude of the current to be detected and the required size of the product.

The outer case 4 is made of phenol-based thermosetting resin, but may be any resin as long as it can accommodate the core and coil, and may be nylon-based thermoplastic resin.
In addition, the present invention is not limited to the resin molded body, and a form in which an insulating tape, insulating paper, or the like is evenly wound on the coil 3 to a certain thickness and is then fixed by varnish treatment.
Further, the center hole portion 4a may be of a size that allows a cable having a conductor cross-sectional area or a conductor diameter corresponding to the magnitude of the current to be detected to penetrate without violently rubbing the inner wall surface of the hole portion. Specifically, φ10 mm or less is desirable. The hole shape is not limited to a circle but may be any shape such as a square or a polygon.

  The material of the L-shaped terminal 5 is preferably a copper-clad steel wire (CP wire) or a hard copper wire having appropriate rigidity and conductivity and excellent in cost. Further, the cross-sectional shape is preferably a circular cross-section with smooth terminal rotation after curling and soldering. Further, the long terminal 5b to be inserted into the outer case of the L-shaped terminal is formed with a crushing portion 5a for stopping the insertion, so that the curled / soldered portion contacts the coil 3 and damages the wire. Since it can prevent structurally giving, the L-shaped terminal which has the crushing part 5a is suitable. Further, the distal end portion of the long side terminal 5b of the L-shaped terminal 5 inserted in the outer case 4 can be performed without touching the short side terminal 5c during rotation or pushing, after being inserted into the outer case 4 Further, a tip portion (not shown) in which the tip portion is bent in an L-shape may be formed, and this portion may be sandwiched with a jig or the like to be rotated and retracted. However, since this tip portion (not shown) is a terminal portion for mounting on the substrate, it is cut again later to make it straight.

  The mold resin 6 is an epoxy-based thermosetting resin, but it is preferable to select an optimal sealing resin while examining various physical properties and characteristics in consideration of the use environment resistance of the current sensor.

The core 1 is made of permalloy of a high permeability material, and 25 thin plate cores obtained by punching a thin plate having a thickness of 0.2 mm into an annular shape having an outer diameter of φ25 mm and an inner diameter of φ15 mm are laminated.
The core case 2 was made of PBT resin having an outer diameter of φ27 mm, an inner diameter of φ13 mm, a height of 6 mm, and a thickness of 0.5 mm, and the core 1 was accommodated therein.
The coil 3 used was a polyurethane-coated copper wire having a wire diameter of φ0.1 mm, and was wound almost uniformly on the entire circumference of the core case 2 for 1000 turns.

The outer case 4 is formed of a phenolic resin molded body having an outer diameter of 35 mm, an inner diameter of 8 mm, a height of 15 mm, and a thickness of 0.5 mm, and both ends of the coil 3 are electrically connected to the outer case 4. These two L-shaped terminals 5 are in a state where the short-side terminal 5c to be bent and soldered is located outside the outer case 4 and is in contact with the upper part of the outer peripheral wall of the outer case 4 to prevent insertion. Has been inserted.
The L-shaped terminal 5 is made of copper-clad steel wire (CP wire) plated with Sn 10%, the outer diameter is φ0.8 mm, and the long side terminal 5b is formed with a crushed portion 5a. Using.

  Subsequently, the coil 3 is housed in the outer case 4, and both end portions of the coil 3 are tangled to the distal end portion of the short-side terminal 5 c of the L-shaped terminal 5, and the solder wire Sn-3Ag-0.5Cu is soldered. After melting and soldering with a trowel and rotating the soldered part so that it fits in the outer case, a jig is applied to the right angle part of the L-shaped terminal 5 until the insertion is stopped by the crushed part 5a until the terminal on the long side 5b was pushed further.

Furthermore, the mold resin 6 was filled with the outer case 4 using S70 (manufactured by Resin Chemical Co., Ltd.), an epoxy thermosetting resin, to obtain the current sensor according to the present invention shown in FIG.
As a comparative example, the conventional current sensor shown in FIG. 3 was prepared using the same material as that of the above-described embodiment of the present invention.

Table 1 shows the results of conducting an environmental test under the following four conditions on the strength of the solder joints of the current sensor according to the present invention and the comparative example manufactured as described above, and measuring the tensile strength before and after the test.
1. High temperature storage test (105 ° C, 1000h)
2. Low temperature storage test (-40 ° C, 1000h)
3. High temperature and high humidity test (60 ° C / 95% RH, 1000h)
4). Thermal shock test (105 ° C for 30 minutes → -40 ° C for 30 minutes is one cycle, 500 cycles)
In addition, this test was implemented in the state which does not carry out the resin molding to an exterior case, in order to eliminate the influence factor of mold resin, and intensity | strength measurement data are taken as the average value of sample n = 10 / test.

  As shown in Table 1, in the current sensor according to the present invention, it was found that the solder joint strength was improved by about 40% compared to the conventional structure, which was greatly improved.

  The embodiments of the present invention have been described above using the embodiments. However, the present invention is not limited to these embodiments, and the present invention is not limited to the scope of the present invention. Included in the invention. That is, various changes and modifications that can be naturally made by those skilled in the art are also included in the present invention.

  With the current sensor of the present invention, it is possible to improve the quality of an abnormal current detector used for a power line or a leakage breaker of a general electronic device, and to contribute to the construction of a highly safe overcurrent protection system.

FIG. 1A is an external view of an L-shaped terminal, FIG. 1B is a sectional view of an exterior case, and FIG. 1C is a front view of the exterior case. FIG. 2A is a cross-sectional view of an outer case after housing and soldering the coil, and FIG. 2B is a front view of the outer case after housing and soldering the coil. The figure explaining the current sensor of this invention, Fig.3 (a) is sectional drawing of the exterior case after rotating an L-shaped terminal, FIG.3 (b) is a front view of the exterior case after rotating an L-shaped terminal. FIG. 4A is a cross-sectional view of the outer case after pushing the L-shaped terminal, and FIG. 4B is a front view of the outer case after pushing the L-shaped terminal. FIG. 5A is a cross-sectional view of an exterior case after resin molding, and FIG. 5B is a front view of the exterior case after resin molding. FIG. 6A is a cross-sectional view of the outer case after rotating the L-shaped terminal, and FIG. 6B is a front view of the outer case after rotating the L-shaped terminal. FIG. 7A is a cross-sectional view of the outer case after pushing the L-shaped terminal, and FIG. 7B is a front view of the outer case after pushing the L-shaped terminal. FIG. 8A is a cross-sectional view of an exterior case after resin molding, and FIG. 8B is a front view of the exterior case after resin molding. FIG. 9A is an external view of an L-shaped terminal, FIG. 9B is a sectional view of an exterior case, and FIG. 9C is a front view of the exterior case. FIG. 10A is a cross-sectional view of the outer case after housing and soldering the coil, and FIG. 10B is a front view of the outer case after housing and soldering the coil. FIG. 11A is a cross-sectional view of the outer case after rotating the L-shaped terminal, and FIG. 11B is a front view of the outer case after rotating the L-shaped terminal. The figure explaining the current sensor of this invention, FIG. 12 (a) is sectional drawing of sectional drawing of the exterior case after resin molding, FIG.12 (b) is front view of sectional drawing of the exterior case after resin molding. FIG. 13 (a) is an external view of a laminated core, FIG. 13 (b) is an external view of a core case, FIG. 13 (c) is an external view of a coil, and FIG. FIG. 13E is a cross-sectional view of the outer case, and FIG. 13F is a front view of the outer case. FIG. 14A is a cross-sectional view of an exterior case after coil storage, and FIG. 14B is a front view of the exterior case after coil storage. FIG. 15A is a cross-sectional view of the outer case when the terminal is bent, FIG. 15B is a cross-sectional view of the outer case after the terminal is bent, and FIG. The front view of the exterior case after pushing and bending. FIG. 16A is a cross-sectional view of an exterior case after resin molding, and FIG. 16B is a front view of the exterior case after resin molding.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Core 2 Core case 3 Coil 4 Exterior case 4a Center hole part 4b Outer wall part upper surface 4c Bottom surface 5 L-shaped terminal 5a Crushing part 5b Long side terminal 5c Short side terminal 6 Mold resin 7 Pushing jig 8 I-shaped terminal 8a Soldering part

Claims (3)

  A current formed by a core made of a high magnetic permeability material, a core case that houses the core, a coil wound around the core case, a terminal that electrically connects a terminal portion of the coil, and an exterior case The current sensor according to claim 1, wherein the terminal has an L shape, and one side of the two bent sides of the L shape penetrates the outer case.   The current sensor according to claim 1, wherein a crushing portion is formed on one side of the two bent sides of the L-shape.   3. The current sensor according to claim 1, wherein a penetration direction of one side of the L-shaped bent side to the exterior case may be a direction perpendicular or horizontal to a bottom surface of the exterior case.

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