JP3967341B2 - Inductor manufacturing method and inductor terminal forming bracket - Google Patents

Description

The present invention relates to a method of manufacturing an inductor used as a choke coil, other coil components, and the like, and also relates to an inductor terminal-forming metal fitting suitable for forming a terminal included in the inductor.

  Conventionally, a magnetic core part is fixed to a core formed by pressurizing magnetic powder integrally or by adhesion, a coil having an insulating layer is disposed on the outer periphery of the magnetic core part, and a coil terminal part composed of both ends of the coil is provided. A surface mount type choke coil having a configuration in which a pair of terminals fixed to a peripheral portion of the core are individually connected is known (for example, see Patent Document 1).

The terminals of the choke coil described in Patent Document 1 are fitted and fixed using an adhesive with the peripheral part of the core sandwiched in the thickness direction. A coil terminal is connected by welding or soldering to one end portion of this terminal, that is, one end portion of the terminal superimposed on one surface of the core from which the magnetic core portion protrudes. Further, the other end of the terminal overlapped on the back surface of the core is used as a mounting terminal when the surface is mounted on the printed wiring board by reflow soldering.
JP 2002-313631 A (paragraphs 0002-0005, FIG. 2)

  As the surface-mounted choke coil (inductor) is reduced in size, the terminal is naturally formed in a smaller size. In order to surface mount the choke coil, a plating layer is provided on the surface of the terminal. In general, so-called barrel plating, in which a predetermined number of terminals are placed in a rotatable barrel and the barrel is rotated, is generally employed for the plating treatment on the terminals.

  By the way, since the coil terminal part is generally connected to a terminal by welding or soldering, at the time of this connection, heat spreads from the connection part to the surroundings. For this reason, as the miniaturization of the terminal is promoted and the heat capacity is reduced, the temperature of the mounting terminal portion located on the back surface of the core is easily increased. As a result, the plating layer on the surface of the mounting terminal portion may be remelted, resulting in a problem that the thickness of this layer fluctuates or oxidation proceeds, which causes poor soldering during surface mounting. It is possible that it will occur. In order to solve this problem, it is required to consider that the entire choke coil (inductor) as a product is not enlarged by the technology.

  Moreover, since the terminal fitted to the core periphery becomes difficult to position for fitting into the core as the size of the product progresses, it is difficult to attach the terminal to a predetermined position of the core with high accuracy. When the variation in the mounting position of the terminal is large, the inductance tends to vary due to the variation, and the improvement is demanded. Incidentally, FIG. 13A shows a histogram of the inductance of the choke coil described in Patent Document 1 with the vertical axis representing pcs and the horizontal axis representing the inductance data section (μH). In this case, the number of samples (pcs) was 200, the average value of μH was 10.19, and σ (standard deviation) was 1.861.

  Further, in the configuration in which the terminal is fitted and fixed to the peripheral portion of the core, it takes a long time to work for positioning the core and the terminal, so that the manufacturing time is long, and improvement thereof is demanded.

A first object of the present invention is to provide an inductor terminal-forming metal fitting capable of suitably obtaining a terminal provided in an inductor that can reduce inductance variation and suppress soldering failure during enlargement and surface mounting. . A second object of the present invention is to provide an inductor manufacturing method that can reduce the variation in inductance and shorten the manufacturing time.

In order to achieve the first object, an inductor terminal-forming metal fitting according to the invention of claim 1 includes a pair of to-be-removed portions to be removed by cutting, continuous with the to-be-removed portions, and integrated with the to-be-removed portions. A terminal forming frame that is partitioned by a pair of independent terminal bases and has a long hole extending along the terminal base, and integrally projects in a direction away from the long hole at one longitudinal end of both terminal bases. And the mounting terminal portion whose front end side portion is bent and the other end portion in the longitudinal direction of the both terminal base portions are integrally projected in a direction away from the long hole, and the front end side portion is removed by cutting. A coil connecting portion.

According to this invention, in the relationship with the core in which the terminal forming metal fitting is combined therewith, the pair of coil connecting portions are fitted into the notches provided in the peripheral portion of the core and engaged with each other. Thus, the terminal forming bracket can be positioned with high accuracy, and the coil connecting portion can be positioned so that the terminal portion of the coil wound around the core can be connected, and the terminal forming bracket can be fixed to the back surface of the core. Therefore, after connecting the terminal portion of the coil to the coil connecting portion, cutting the tip side portion of the coil connecting portion from the portion where the terminal portion is connected, and cutting the removal planned portion of the terminal forming frame, A pair of terminals can be formed without requiring the operation of individually bonding the terminals to the back surface of the core by making the terminal bases located between the long holes of the terminal forming frame independent from each other so as not to be short-circuited.

In order to achieve the second object, an inductor manufacturing method according to the invention of claim 2 includes a pair of to-be-removed portions to be removed by cutting, and the removal-to-be-removed portions that are integrally continuous and independent by the cutting. A terminal forming frame having a long hole that is partitioned by a pair of terminal bases and that extends along the terminal base, and integrally protrudes in a direction away from the long hole at one end in the longitudinal direction of the both terminal bases, A mounting terminal portion whose front end portion is bent, and a coil projecting integrally at the other end in the longitudinal direction of both terminal base portions in a direction away from the long hole, and the front end portion being removed by cutting A first core having a base part provided with a pair of notches opened on a peripheral surface and a magnetic core part protruding from one surface of the base part is fixed on a terminal forming metal fitting having a connection part. And fix this end Performs the base portion rear surface to the base by bonding with an adhesive, whereby to engage a pair of said coil connecting portions to said notches respectively to be, by positioning the first core in the terminal forming metal,
Next, the coil is wound around the magnetic core portion, the terminal portion at the beginning of winding of the coil and the terminal portion at the end of winding are entangled with the coil connecting portion, respectively, and the winding start of the coil is wound around the coil connecting portion. Electrically and mechanically connecting the terminal part and the terminal part at the end of winding, and then removing the distal end side portion of the coil connecting part located first from the electrical and mechanical connection position by cutting, The pair of to-be-removed portions are removed by cutting, the pair of terminal bases are made independent to form a terminal, and then the coil is accommodated in the second core, and the second core is bonded to the base portion. It is fixed by.

In the method of the present invention, since the terminal forming metal fitting combined with the core having a pair of notches in the peripheral portion is the terminal forming metal fitting according to claim 1 , the pair of coil connecting portions are arranged around the core. By fitting and engaging with the notch provided in the part, the terminal forming bracket can be accurately positioned with respect to the core, and the coil connecting part is positioned so that it can be connected to the terminal part of the coil wound around the core. Thus, this terminal forming metal fitting can be fixed to the back surface of the core. Next, after connecting the terminal portion of the coil wound around the magnetic core portion of the core to the coil connecting portion, the distal end portion of the coil connecting portion is cut from the portion where the terminal portion is connected, and the terminal forming frame By cutting the part to be removed, the terminal bases located between the long holes of the terminal forming frame are made independent from each other so as not to be short-circuited, and without requiring the operation of individually bonding the terminals to the back surface of the core, A pair of terminals can be formed. Therefore, the pair of terminals can be easily and highly accurately positioned with respect to the core, and the pair of terminals can be manufactured without requiring the trouble of individually attaching the pair of terminals to the core.

According to the first aspect of the present invention, it is possible to provide an inductor terminal-forming metal fitting capable of suitably obtaining a terminal provided in an inductor that can suppress an increase in size and a soldering failure at the time of surface mounting while reducing variation in inductance.

According to the second aspect of the present invention, since the pair of terminals can be easily and accurately positioned with respect to the core, variation in inductance can be reduced, and it is not necessary to separately attach the pair of terminals to the core. It is possible to provide an inductor manufacturing method with a short time.

  An embodiment of the present invention will be described with reference to FIGS.

  The inductor shown in FIG. 1 is used as a choke coil 1 through which a large current flows. As shown in FIGS. 2 to 5, the choke coil 1 includes a first core 11, a coil 18, a pair of terminals 21, and a second core 31.

  The first core 11 is a green compact obtained by pressure molding a mixed powder obtained by mixing magnetic powder and a binder using a mold of a pressure molding apparatus (not shown). Examples of magnetic powder include ferrite powder, magnetic metal powder such as carbonyl iron powder, and the like. An insulating resin can be suitably used for the binder.

  As shown in FIGS. 4 to 6 and the like, the first core 11 has, for example, a base portion 12, a magnetic core portion 13, and a head portion 14 to form a drum shape. A peripheral portion of the base portion 12 has an arc shape, and a notch 15 is provided in the peripheral portion at a distance of 180 °. Since both side surfaces of the pair of notches 15 penetrating the base portion 12 in the thickness direction are inclined, the notches 15 opened to the peripheral surface of the base portion 12 are gradually narrowed from the open end to the back. It is formed to become. The magnetic core portion 13 has a columnar shape, for example, a columnar shape, and protrudes integrally at the center of one surface of the base portion 12. The head portion 14 has a circular shape smaller than the base portion 12, and a magnetic core portion 13 is integrally provided at the center portion thereof.

  The coil 18 is made of an insulation-coated copper wire or the like, and is disposed so as to be sandwiched between the base portion 12 and the head portion 14 and is wound around the outer periphery of the magnetic core portion 13.

  As shown in FIG. 2, the pair of terminals 21 are fixed to each other in a non-contact state with a surface opposite to the surface on which the magnetic core portion 13 of the first core 11 protrudes, that is, the back surface using an adhesive. . These terminals 21 are obtained by cutting a terminal forming metal fitting 25 described later, and are provided in a point-symmetric arrangement with the center of the back surface of the base portion 12 as a symmetry point P (see FIG. 2).

  Each terminal 21 has a terminal base portion 22, a mounting terminal portion 23, and a coil connection portion 24.

  The terminal base portion 22 is fixed to the back surface of the first core 11, and both ends thereof are slightly protruded from the peripheral edge of the first core 11.

  As shown in FIGS. 2 and 5, the mounting terminal portion 23 protrudes from one end portion in the longitudinal direction of the terminal base portion 22, and the distal end side portion 23 a is bent along the peripheral surface of the base portion 12. The height of the distal end side portion 23 a is equal to or less than the thickness of the base portion 12. The mounting terminal portion 23 and the terminal base portion 22 are used as soldering surfaces when the choke coil 1 is surface-mounted.

  As shown in FIGS. 2 and 4, the coil connection portion 24 is formed by being bent from the other end portion in the longitudinal direction of the terminal base portion 22. Therefore, the integrated mounting terminal portion 23 and the coil connection portion 24 are disposed away from each other along the direction in which the terminal base portion 22 extends through the terminal base portion 22. The angle θ between the straight line connecting the symmetry point P and the center of the mounting terminal portion 23 and the straight line connecting the symmetry point P and the center of the coil connection portion 24 is 90 degrees, for example.

  The coil connection part 24 is bent at a right angle to the terminal base part 22 and parallel to the terminal base part 22. A portion parallel to the terminal base portion 22 of the coil connection portion 24 is referred to as a distal end side portion 24a. The coil connecting part 24 enters the notch 15 and is engaged with the inner part of the notch 15. By this engagement, the terminal 21 is positioned with respect to the first core 11. Most of the distal end side portion 24a is cut off, but in the state before this cutting off, as shown in FIGS. 6 to 9, the distal end side portion 24a is bent in an L shape in plan view. A tangled groove 24b made of a V-groove or the like is provided in a portion where the tip side portion 24a is cut off.

  As shown in FIG. 3, FIG. 4, FIG. 10, etc., a terminal portion (referred to as a coil terminal portion) 18a of the coil 18 is electrically and soldered, for example, by welding or soldering. Mechanically connected. In FIG. 3 and FIG. 10, reference numeral 19 indicates a connection mark such as a solder pile.

  The second core 31 is a green compact of a mixed powder obtained by mixing a binder with a magnetic powder of the same or different type as the first core 11, and is formed into a ring shape as illustrated in FIGS. Has been. The second core 31 accommodates the head portion 14 and the coil 18 therein and is fixed to the base portion 12 with an adhesive. As shown in FIG. 12, a pair of escape grooves 31a is formed at the end of the second core 31 located near the head portion. These escape grooves 31 a are larger than the notch 15. In a state where the second core 31 is combined with the head portion 14, the notch 15 faces the escape portion 31a. Due to this positional relationship, as shown in FIG. 4, the coil terminal portion 18 a and the connection trace 19 are not in contact with the second core 31. Further, due to the height relationship of the distal end side portion 23a of the mounting terminal portion 23 with respect to the base portion 12, the distal end side portion 23a is not in contact with the second core 31 as shown in FIG.

  With reference to FIG.6 and FIG.11, the terminal formation metal fitting 25 prepared in order to obtain the said pair of terminal 21 is demonstrated. The terminal forming metal fitting 25 includes a terminal forming frame 26, a pair of positioning portions 27, a pair of mounting terminal portions 23, and a pair of coil connecting portions 24.

  The terminal forming frame 26 is partitioned by a pair of to-be-removed portions 26 a to be removed by cutting and a pair of the terminal base portions 22, and has a frame shape having a long hole 28 extending along both the terminal base portions 22. . The pair of terminal base portions 22 are independent by cutting the removal planned portion 26a integrally and continuously therewith. The removal planned portions 26a protrude from both ends of the long holes 28 in the direction in which the long holes 28 extend, and the removal planned portions 26a are provided with positioning portions 27, respectively. These positioning portions 27 are formed of holes opened in the planned removal portion 26a, for example. The mounting terminal portion 23 integral with the terminal base portion 22 is integrally projected in a direction away from the long hole 28. Similarly, the coil connecting portion 24 integral with the terminal base portion 22 is also integrally projected in a direction away from the long hole 28.

  Each of the terminal base portions 22 has a convex portion 29 protruding integrally in the long hole 28. The terminal forming frame 26 is formed, for example, by punching and bending a copper plate, and a plating layer is applied to the surface thereof by barrel plating. In this barrel plating, a large number of terminal forming frames 26 are put into the barrel at a time for processing. Therefore, if another terminal forming frame 26 enters the long hole 28 in this plating process, the terminal forming frame 26 may be deformed. The yield rate is reduced. However, by providing the above-described convex portion 29, it is possible to suppress the other terminal forming frame 26 from entering the elongated hole 28 during the barrel plating, and to improve the yield rate of the terminal forming frame 26 and thus the terminal 21. This is preferable.

  Next, the assembly procedure of the choke coil 1 will be described.

  First, as shown in FIG. 7 from the state shown in FIG. 6, the back surface of the base portion 12 of the drum-type first core 11 is overlaid on the terminal forming frame 26 of the terminal forming metal fitting 25, and the first core 11 is bonded not shown. It fixes on the terminal formation frame 26 using an agent. In this case, since the coil connecting portion 24 of the terminal forming metal fitting 25 enters and engages with each of the notches 15 of the base portion 12, the first core 11 is prevented from moving back and forth and left and right at a predetermined position of the terminal forming metal fitting 25, Accordingly, the rotation is also prevented in the circumferential direction. In this combined state, the distal end side portion 23 a of the mounting terminal portion 23 is disposed along the peripheral surface of the base portion 12. Not only that, the distal end side portion 24a of the coil connecting portion 24 of the terminal forming metal fitting 25 is positioned so as to protrude outside the base portion 12, and the removal planned portion 26a forming both end portions in the longitudinal direction of the terminal forming frame 26 is also provided. It is positioned so as to protrude outside the base portion 12 at a position different from the coil connection portion 24.

  Next, the assembly E shown in FIG. 7 is set in a winding machine or a winding jig (not shown). In this set, by attaching the positioning portions 27 at both ends in the longitudinal direction of the terminal forming frame 26 to positioning portion receivers such as convex portions of the winding machine or the winding jig, the winding machine or the winding jig On the other hand, the assembly E of FIG. 7 can be set at an appropriate position. Thereafter, a coil 18 is wound around the magnetic core portion 13 of the first core 11 as shown in FIG. Therefore, since the locus of the coil 18 can be determined at the same position by the positioning, the winding work is facilitated.

  In this winding work, first, the coil terminal portion 18 a on the winding start side of the coil 18 is entangled in the entanglement groove 24 b of one coil connection portion 24 of the terminal forming bracket 25, and then the coil 18 with respect to the magnetic core portion 13 is moved. Winding is performed, and after the winding is completed, the winding end side of the coil 18 is bound to the binding groove 24b of the other coil connecting portion 24 of the terminal forming metal fitting 25, and then the coil 18 is cut and executed. It is desirable. FIG. 9 shows a state in which both coil terminal portions 18a are entangled.

  When the coil 18 is wound around the magnetic core portion 13, the force in the winding direction acting on the first core 11 becomes a load for adhesion between the first core 11 and the terminal forming frame 26. However, since the notch 15 of the first core 11 is hooked and engaged with the coil connection portion 24 of the terminal forming frame 26 as described above, the load can be distributed and supported at this portion. For this reason, the adhesion peeling between the first core 11 and the terminal forming frame 26 can be suppressed. Further, by realizing the rotation prevention in the circumferential direction by the engagement, it is possible to prevent the first core 11 from being peeled off from the terminal 21 or causing the coil 18 to be disconnected due to an external force applied in a product state.

  After the above winding, the coil terminal portion 18a is electrically and mechanically connected to the base side portion of the coil connecting portion 24 by soldering or the like. Along with this connection, the coil connection portion 24 is heated.

  By the way, since the coil connection part 24 of the terminal formation metal fitting 25 has the front end side part 24a which extended ahead from the root part and had the entanglement groove 24b, it can anticipate heat dissipation from this part 24a to the exterior. . In addition, the heat conduction path between the coil connection portion 24 provided at one end of the terminal base portion 22 and the one mounting terminal portion 23 positioned with the long hole 28 therebetween is long. Along with the length of the hole 28, there is a portion 26a to be removed in the middle of the path, and heat can be expected to be released from the portion 26a to the outside. For this reason, the spread of the heat to said one mounting terminal part 23 can be suppressed. Further, the coil connecting portion 24 provided at one end portion of the terminal base portion 22 and the other mounting terminal portion 23 provided at the other end portion of the terminal base portion 22 are not restricted by the thickness of the base portion 12, and the terminal base portion. It is separated by the length of 22, and heat can be radiated to a wide range of the base portion 12 through the terminal base portion 22, and heat radiation to the outside can also be expected. For this reason, the spread of heat to the other mounting terminal portion 23 can be suppressed.

  Therefore, the temperature rise of the pair of mounting terminal portions 23 due to the connection is suppressed, the plating layer on the surface of the mounting terminal portions 23 is remelted, and the thickness of this layer varies or oxidation proceeds. Can be prevented. Thus, when the choke coil 1 configured as a product is surface-mounted on a printed wiring board of an electronic device (not shown), the soldering failure can be prevented from occurring.

  Next, the electrical and mechanical connection positions of the coil terminal portions 18a with respect to the pair of coil connection portions 24, that is, the connection traces 19 are left, and the distal end side portions 24a are cut and removed therefrom. The cutting line in this case is indicated by a dotted line Z1 in FIG. At the same time, the pair of to-be-removed portions 26 a are cut and removed across the long hole 28 to make the pair of terminal base portions 22 independent, thereby forming the pair of terminals 21. The cutting line in this case is indicated by a dotted line Z2 in FIG. In addition, the above cutting | disconnection is implemented without a heating by performing a cutting process simultaneously using a press die. FIG. 10 shows an assembly F of the first core 11 and the pair of terminals 21 subjected to this processing.

  In this assembly F, since at least half of the coil connection part 24 left by the cutting is accommodated in the notch 15, the protruding dimension of the coil connection part 24 is small. Accordingly, it is possible to suppress an increase in the maximum diameter of the coil connecting portion 24 when the assembly F is viewed in a plan view, and consequently, the outer dimensions of the choke coil 1 that is a product.

  Finally, the ring-shaped second core 31 is combined with the assembly F of FIG. In other words, the head portion 14 and the coil 18 are accommodated in the second core 31 and the second core 31 is fixed to the base portion 12 of the first core 11 with an adhesive. In this case, since the escape groove 31a is provided in the second core 31, it is possible to prevent the second core 31 from hitting the coil terminal portion 18a and causing a defect. The choke coil 1 thus assembled is shown in FIG. 1, FIG. 2, FIG. 4, and FIG. In addition, the dimension of each part shown by M in FIG. 12 of the second core 31 that substantially determines the size of the choke coil 1 is 3.0 mm. The diameter of the base portion 12 of the first core 11 to which the second core 31 is fixed is 2.8 mm.

  In the manufacturing method of the small choke coil 1 described above, the pair of coil connection portions 24 provided on the terminal forming metal fitting 25 are fitted into the notches 15 in the peripheral portion of the first core 11 and engaged as described above. Thereby, it is possible to accurately position the terminal forming metal fitting 25 and the pair of terminals 21 fixed to the back surface of the first core 11 with an adhesive while maintaining their relative positions in a predetermined state. In addition, since the terminal forming metal fitting 25 is used, the two terminals 21 can be easily positioned by a single operation. And after connecting the coil terminal part 18a of the coil 18 wound around the magnetic core part 13 of the 1st core 11 to the coil connection part 24, while cutting | disconnecting the tip end side part 24a side of the coil connection part 24, and terminal formation A pair of terminals 21 can be formed by cutting the planned removal portion 26a of the frame 26 and making the terminal base portions 22 independent of each other. For this reason, the operation | work which adhere | attaches a pair of terminal 21 on the back surface of the base part 12 of the 1st core 11 separately is not required, and there is also no troublesome to fit these terminals 21 to the peripheral part of the base part 12 separately. As described above, since the attachment of the pair of terminals 21 to the base portion 12 of the first core 11 can be improved, the manufacturing time of the choke coil 1 can be significantly reduced to, for example, about 2/3 of the prior art.

  In addition, since the pair of terminals 21 can be positioned with high accuracy on the first core 11 as described above, variations in the assembly dimensions of the choke coil 1 can be suppressed, and changes in inductance caused thereby can be suppressed. Incidentally, FIG. 13B, in which the vertical axis is pcs and the horizontal axis is the inductance data section (μH), shows a histogram of the inductance of the choke coil 1 produced by the above-described manufacturing method. In this case, the number of samples (pcs) was 200, the average value of μH was 10.00, and σ (standard deviation) was 1.140. From this result, it was found that the variation in inductance was improved as compared with the conventional case.

  Moreover, since the choke coil 1 made by the above-described manufacturing method has a small projecting width of the coil connecting portion 24 with respect to the first core 11 as described above, the overall size can be suppressed. Furthermore, since the terminal 21 is attached to the first core 11 with high accuracy as described above, the variation in inductance is suppressed and the quality can be improved. In addition, since the influence of heating associated with the connection of the coil terminal portion 18a to the coil connection portion 24 does not easily affect the mounting terminal portion 23, soldering when the choke coil 1 is surface-mounted on a printed wiring of a printed wiring board (not shown). It is excellent in that defects can be suppressed.

  In addition, by using the terminal forming metal fitting 25 in the manufacturing method, it is possible to suitably obtain the terminal of the choke coil 1 that has a small variation in inductance as described above, and can suppress an increase in size and a soldering failure during surface mounting. it can.

  The present invention is not limited to the one embodiment. For example, a so-called rivet-type core that does not have a head portion is used for the first core, and an inductor such as a choke coil that uses a so-called pot-type core consisting of an end wall and a side wall integrally provided around the second core. However, the present invention is applicable.

The perspective view which shows the choke coil manufactured with the manufacturing method which concerns on one Embodiment of this invention. The back view which shows the choke coil of FIG. The perspective view which decomposes | disassembles and shows the choke coil of FIG. Sectional drawing of the choke coil shown along F4-F4 line in FIG. Sectional drawing of the choke coil shown along the F5-F5 line in FIG. The perspective view shown in the state which mutually isolate | separated the relationship between the terminal formation metal fitting which concerns on one Embodiment of this invention which forms the terminal of the choke coil of FIG. 1, and a 1st core. The perspective view which shows the state which the 1st core was combined with the terminal formation metal fitting which forms the terminal of the choke coil of FIG. The perspective view which shows the state by which the coil was wound by the 1st core combined with the terminal formation metal fitting. The perspective view which shows the state by which the terminal part of the coil wound around the 1st core was wound around the coil connection part of a terminal formation metal fitting. The perspective view which shows the state by which the terminal part of the coil was connected to the coil connection part of the terminal formation metal fitting. (A) is a top view which shows the terminal formation metal fitting which forms the terminal of the choke coil of FIG. (B) is an arrow view which shows a terminal formation metal fitting seeing from the arrow W direction in FIG. 11 (A). (C) is an arrow view which shows a terminal formation metal fitting seeing from the arrow V direction in FIG. 11 (A). (A) is a back view which shows the 2nd core of the choke coil of FIG. FIG. 12B is a cross-sectional view taken along the line XX in FIG. FIG. 12C is a cross-sectional view taken along the line YY in FIG. (A) is a histogram which shows the dispersion | variation in the inductance of the choke coil which concerns on the past. (B) is a histogram showing variation in inductance of the choke coil of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Choke coil, 11 ... 1st core, 12 ... Base part, 13 ... Magnetic core part, 14 ... Head part, 15 ... Notch, 18 ... Coil, 18a ... Coil terminal part, 19 ... Connection trace, 21 ... Terminal 22 ... terminal base, 23 ... mounting terminal, 23a ... tip side part, 24 ... coil connection part, 24a ... tip side part, 25 ... terminal forming metal fitting, 26 ... terminal forming frame, 26a ... part to be removed, 28 ... Long hole, 31 ... second core

Claims (2)

  A pair of to-be-removed portions to be removed by cutting, and a terminal having a long hole that extends integrally with the to-be-removed portions and is separated by a pair of terminal bases that are independent of each other by cutting. Frame,
  A mounting terminal portion that is integrally protruded in a direction away from the elongated hole at one end portion in the longitudinal direction of the both terminal base portions, and a distal end side portion thereof is bent,
  A coil connecting portion that is integrally projected in the direction away from the elongated hole at the other longitudinal end of the both terminal bases, and whose tip side portion is removed by cutting;
Inductor terminal-forming metal fittings.   A pair of to-be-removed portions to be removed by cutting, and a terminal having a long hole that extends integrally with the to-be-removed portions and is separated by a pair of terminal bases that are independent of each other by cutting. A frame, a mounting terminal portion integrally projectingly provided at one end portion in the longitudinal direction of the both terminal base portions in a direction away from the elongated hole, and a distal end portion thereof being bent, and the other longitudinal end of the both terminal base portions On the terminal forming metal fitting provided with a coil connecting portion that is integrally projected in the direction away from the elongated hole in each of the portions, and the tip side portion is removed by cutting,
  Fixing a first core having a base portion provided with a pair of notches that are open to the peripheral surface, and a magnetic core portion protruding from one surface of the base portion;
  This fixing is performed by adhering the back surface of the base portion to the terminal base portion with an adhesive, and at that time, a pair of the coil connection portions are engaged with each of the notches, and the first core is connected to the terminal. Positioning to the forming bracket,
  Next, the coil is wound around the magnetic core portion, the terminal portion at the beginning of winding of the coil and the terminal portion at the end of winding are entangled with the coil connecting portion, respectively, and the winding start of the coil is wound around the coil connecting portion. Electrically and mechanically connect the terminal part and the terminal part at the end of winding,
  Next, the distal end portion of the coil connection portion located first from the electrical and mechanical connection position is removed by cutting, and the pair of planned removal portions are removed by cutting to remove the pair of terminal base portions. Forming the terminals independently,
  Next, an inductor manufacturing method in which a coil is housed in the second core and the second core is fixed to the base portion with an adhesive.

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