JPH09199367A - Method for manufacturing inductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing readily an inductor high in quality and reliability by a method wherein a lead-out part of a coil wound on a core is readily, accurately and fixedly connected to a lead frame terminal on both end faces of the core, and a space allowable degree at the time of mold resin sealing is prepared. SOLUTION: First, a core 1 provided with a recess part 5 on both end faces is prepared. Next, a solder fixed layer 6 is formed in the recess part 5, and solder 7 is filled into the recess part 5 with the solder fixed layer 6. Next, a lead wire 8 is wound on a drum part 3 of the core 1, and a lead-out portion 8A at both ends of the coil is fixedly connected to the solder filled part 7 of the recess part 5 by melting solder. After cutting out and removing the lead wire 8, a top end part 10A of a lead frame terminal 10 is connected to the solder filled part 7 of the recess part 5 by melting solder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an inductor, and more particularly to a method for manufacturing an inductor for electric equipment in which a conductor wire is wound around a core made of ferrite and resin-sealed.

[0002]

2. Description of the Related Art Japanese Patent Publication No. 55-36179 discloses an example of a conventional method of manufacturing an inductor in which a conductor is wound around a core of ferrite or the like and resin-sealed.
First, a core-shaped recess is provided in the flanges on both end faces of the core, and a conductive coating such as a silver material is attached to the surface of the recess. Next, a conductive wire is wound around the body of the core. And
Pull out both ends of the winding, insert the extraction into the recesses provided on both end faces of the core, insert the ends of the lead terminals into the recesses at the same time, and fill the solder with the extraction of the winding. The lead terminal was fixed in the recess of the core.

However, in this case, the lead-out portion of the winding and the tip of the lead terminal must be fixed in the recess by some method and then filled with solder, which is the core of the component of this type. Outer dimension of the collar is 1
Since it is very small, about 2 mm, there is a problem that workability is poor.

Further, according to another conventional example, a core is similarly prepared in which recesses are formed in the flange portions at both ends, and an electrode layer of silver material or the like is formed in the recesses. Then, the lead-out portion of the winding is fixed to the electrode layers of the recesses on both end surfaces of the core by pressure bonding, and the tip end portions of the lead frame terminals are connected to the electrode layers by soldering. In order to crimp-bond the conductor wire, the conductor wire had to be crimped to the electrode layer with high heat and pressure. Since the conductor wire is pressed and squeezed, the adhesive strength is weak, and the strength of the conductor itself is inferior. Further, there is a problem in that cutting and removal of the unnecessary conductor portion of the conductor in the next step becomes unstable due to instability of the crushing amount.

Similarly, when the tip portion of the lead frame terminal is soldered to the electrode layer of the core, the lead layer terminal is connected to the electrode layer only by the solder plating layer of the frame. There was a problem of weak strength.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and the lead-out portion of the winding wound around the core and the lead terminal can be easily and surely connected at both end surfaces of the core. It is an object of the present invention to provide a method of manufacturing an inductor which can be manufactured, is easy to manufacture, and has high quality and reliability.

[0007]

A method of manufacturing an inductor according to the present invention comprises a step of preparing a core having concave portions on both end surfaces, a step of forming a solder fixing layer for fixing solder in the concave portions, and a step of forming the solder. The step of filling the solder in the concave portion in which the fixed layer is formed, and winding the lead wire around the body of the core and connecting the lead-out portions of both ends of the winding by melting the solder in the solder filling portion of the concave portion And a step of melting and connecting the tip portion of the lead frame terminal with the solder in the solder filling portion of the recess after cutting and removing the unnecessary conductor wire portion of the conductor wire.

According to the present invention, the recesses on both end surfaces of the core are filled with solder in advance, and the lead-out portion of the core winding is heated by a heating means such as a heater chip to melt and fix the solder. Therefore, the lead-out portion of the winding can be easily and reliably fixedly connected to the solder-filled portion of the recess by the large amount of solder filled in the recess. Similarly, since the lead portions of the lead frame terminals are also melted and connected with a large amount of solder in the pre-filled recesses, they can be easily and reliably connected to the solder-filled portions of the recesses. Therefore, the lead-out portion of the lead wire and the tip portion of the lead frame terminal are securely connected by the solder filling portion.

[0009]

An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a perspective view of a core portion of an inductor according to an embodiment of the present invention, and FIG. 2 is a sectional view thereof. A core 1 made of a material such as ferrite has collars 2 on both end faces.
And a conductor is wound around the body 3 to form a coil. Recesses 5 are formed in advance on both end surfaces of the collar 2 of the core 1, and the lead wire portion of the coil winding and the tip end portion of the lead frame terminal led out to the outside are electrically connected by soldering at this portion. In addition, it is firmly fixed to the core part. The collar 2 is necessary when the coil winding is formed into a multi-layer winding, but may be a so-called columnar core for high frequency single layer winding in which the body 3 and the collar 2 have the same diameter.

Next, a material for fixing the solder is injection-coated or transfer-coated on the inner surface of the recess 5 and the solder fixing layer 6 is applied at a high temperature.
To form The recess 5 may have a dish shape as shown in FIG. 2 or a mortar shape. Since there are recesses on both end surfaces of the core, the core can be positioned and the solder fixing layer 6 can be easily formed. Moreover, because of the concave shape, it is not necessary to flatten the material after application or printing.

Next, as shown in FIG. 3, the concave portion 5 is filled with solder to form a solder filling portion 7. In this, by immersing the core 1 having the solder fixing layer 6 formed in the recess 5 in a solder bath of molten solder, it is possible to easily fill the recess 5 with the solder. Further, instead of immersing the molten solder in the solder bath, the solder paste may be filled to the recess 5 and heated to fill the solder in the recess 5.

Next, as shown in FIG. 4, the conductor wire 8 is wound around the body portion 3 of the core 1 to form a coil. And leader line section 8
By extending A onto the solder filling portion 7 and pressing the heater chip 9, the lead wire portion 8A can be pushed into the solder filling portion 7 by melting the solder at a relatively low temperature and low pressure. By pulling back the heater chip 9, the solder is cooled and solidified, and the lead wire portion 8A is fixedly connected in a state of being embedded in the solder filling portion 7 as shown in FIG.

Since the recess 5 has a sufficient depth with respect to the conductor wire, even if the conductor wire is pushed in by a heater chip or the like, it does not hit the solder fixing layer 6 at the bottom, and the conductor wire does not slip. Further, when the conductor wire is pushed into the solder filling portion 7, since the solder is melted into a liquid by the heater chip, the conductor wire is pushed into the molten solder liquid, so that the conductor wire is surely covered with the solder and the solder filling portion 7 is covered. It is fixed and electrically connected.

Next, the lead wire on the winding start side of the lead wire portion 8A is cut and removed. Since a part of the lead wire portion 8A is embedded and fixedly connected in the solder filling portion 7, the lead wire portion 8A can be stably cut and removed without considering peeling from the connecting portion of the conductor wire. Even when the conductor wire on the winding end side is cut, the conductor is firmly fixed and connected to the core end face by the solder filling portion 7, so that the conductor wire is
Can be cut without protruding. If the lead wire protrudes from the outer diameter of the core, it cannot be mounted stably on the lead frame.

Next, as shown in FIG. 5, the lead frame 1
The lead frame terminal tip portion 10A of No. 0 is connected and fixed to the solder filling portion 7. This is also because the lead frame terminal tip portion 10A of the lead frame 10 on which the solder plating has been performed is pressed by a relatively low-temperature and low-pressure heating pressing means such as a heater chip, whereby the solder is melted and the inside of the solder filling portion 7 is filled. Can be embedded and fixedly connected to.

Next, according to the conventional inductor manufacturing process, molding resin encapsulation is performed, a display mark is imprinted, the lead frame terminal is cut from the lead frame, bent, and homing. A resin-sealed chip-type inductor is completed.

As described above, according to the manufacturing method described above,
Lead wire lead portion 8A and lead frame terminal tip portion 10A
Are reliably soldered to each other by the large amount of solder filling portion 7 in the recess 5 of the core. For this reason, an electrically stable and reliable connection state can be obtained, and mechanically strong fixing can be obtained. In addition, since the lead wire and the lead frame terminal are connected to each other by the recessed portion on the end face of the core, a space margin can be obtained when the molding resin is sealed. Further, the number of manufacturing steps of the inductor is small, and the inductor can be manufactured with simple equipment.

The conducting wire has an insulating coating made of synthetic resin or the like on the outer circumference of the conducting wire. When the conductor wire is pushed in by the heater chip, the insulating film hits the tip of the heater chip and adheres, but when the heater chip completes pushing and returns, the tip portion of the heater chip is melted with a sufficiently large amount of molten solder liquid. Is washed, and there is no film adhesion, and stable and continuous solder connection is possible.

Since it is the solder that fixedly connects the lead wire to the solder filling portion, a simple heat source such as a soldering iron and a simple mechanism for pushing the lead wire into the recess can be manufactured. Since this is a simple mechanism, both the solder-filled portions of the recesses at both ends of the core and the conductive wire can be solder-connected simultaneously. Since the core is held by a jig of a machine or the like, when the solder in the recess is heated by the heater chip, heat escapes to the holding jig, resulting in heat loss. When the solder in the recesses on both ends is melted on each side, a higher temperature is required than for simultaneous soldering on both sides, and the time becomes longer. If both ends are soldered at the same time, the heat stress to the core, the conductive wire, and the electrode layer is small, and the quality is improved. Moreover, since the heating time can be shortened, the production capacity is improved.

Since the concave portion is filled with solder,
Even when the lead wire is off the center of the end face of the core, the conductor wire is covered with the molten solder extruded on the heater chip and is securely soldered. The recess in the core end face and the solder filled in the recess also have a buffering effect on the movement and pressure of the heater chip.

[0022]

As described above, according to the method for manufacturing an inductor of the present invention, the chip heater is provided in the solder-filled portion of the recessed portions at both ends of the core in which the lead-out portion of the coil winding and the tip portion of the lead frame terminal are formed in advance. For example, it is pushed in and fixedly connected. Therefore, at a relatively low temperature and low pressure, the lead-out portion of the coil winding and the lead frame terminal tip can be easily and firmly connected electrically and mechanically by the solder-filled portions in the recesses at both ends of the core. it can. Therefore, according to the present invention, a molded resin-sealed inductor having high quality and reliability can be manufactured by a simple manufacturing method.

[Brief description of drawings]

FIG. 1 is a perspective view of a core having concave portions on both end surfaces.

FIG. 2 is a cross-sectional view showing a state in which a solder fixing layer is formed in the recess of the core.

FIG. 3 is a cross-sectional view showing a state where a solder filling portion is formed in a concave portion of the core.

FIG. 4 is a cross-sectional view showing a state in which a lead-out portion of a conductive wire is embedded and fixedly connected to a solder filling portion.

FIG. 5 is a cross-sectional view showing a state in which a lead tip portion of a lead frame is embedded and fixedly connected to a solder filling portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 core 2 core collar part 3 core body part 5 core concave portions on both end surfaces 6 solder fixing layer 7 solder filling part 8 conductor wire 8A lead-out part 9 heater chip 10A lead frame terminal tip part

Claims (1)

[Claims] 1. A step of preparing a core having concave portions on both end surfaces, a step of forming a solder fixing layer for fixing solder in the concave portions, and a step of filling the concave portions in which the solder fixing layers are formed with solder. A step of winding a conductor wire around the body of the core and fixing and connecting the lead-out portions at both ends of the winding by melting the solder in the solder filling portion of the recess, and after cutting and removing the unnecessary conductor wire portion of the conductor wire And a step of melting the solder in the solder filling portion of the recess to connect the tip portion of the lead frame terminal.