JP2004186406A - Miniature coil and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a miniature coil that is strengthened against a shock and reduced in the manufacturing cost. <P>SOLUTION: The miniature coil is configured with a core 1 integrally formed with a cylindrical drum core 12 having a flange 13 and a box shaped ring core 11 for enclosing and shielding the drum core 12, two left right terminal boards 2 one-side ends of which are embedded to a side face of the ring core 11 and fixed thereto at the same time when the drum core section 12 and the ring core section 11 are integrally formed, and a winding 3 wound on the drum core section 12. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a small coil and a method for manufacturing the same, and more particularly to a small coil used for a mobile phone and the like and a method for manufacturing the same.
[0002]
[Prior art]
This kind of small coil is used for a power supply of a mobile phone or the like, a voltage boosting / decreasing circuit for a display unit, and the like, and in particular, it is required to have a strength against an impact from its use environment.
[0003]
A general configuration of this kind of small coil is a cylindrical drum core, a cylindrical or box-shaped ring core that wraps and shields the drum core, a winding wound around the drum core, and winding start and end of the winding. It is composed of a terminal board to be connected. FIG. 4 shows a conventional example of the most basic configuration.
[0004]
FIG. 4A is a perspective view schematically showing a conventional example, and FIG. A drum core 41 having a flange portion 411, a ring core 42 covering the outside thereof, a terminal base 43 on which the drum core 41 and the ring core 42 are mounted, a terminal plate 45 embedded in the terminal base 43, and a winding wound around the drum core 41. And a line 44. The drum core 41 is integrally formed with or bonded to the terminal block 43. Further, the ring core 42 is bonded to the terminal block 43. The lead wires at the beginning and end of the winding 44 are welded to the left and right terminal plates 45, respectively. In particular, in this small coil, the flange portion 411 of the drum core 41 passes through a circular hole formed in the ceiling of the ring core 42 in order to suppress the height.
[0005]
The small coil is used by soldering a terminal board 45 to a printed circuit board and mounting it on a plane.
[0006]
FIG. 5 shows another conventional example. 5A and 5B are a perspective view and a sectional view, respectively, showing another conventional example. This conventional example is different from FIG. 4 in that it is an example of a small transformer using a bobbin with a cylindrical ring core, in which insulation between primary and secondary windings is particularly improved.
[0007]
This small transformer includes a drum core 51 having upper and lower flanges, a bobbin 57 mounted on the drum core 51 and winding a coil, a ring core 52 mounted on the outer periphery of the bobbin 57, and a primary core wound on the drum core 51. A winding 53, a secondary winding 55 wound around a bobbin 57, a base 53 on which the drum core 51, the bobbin 57 and the ring core 52 are mounted and fixed, and a winding start and end of the winding are drawn out. And a terminal pin 54. An upper flange portion of the drum core 51 and an upper flange portion of the bobbin 57 pass through a circular hole provided at an upper portion of the ring core 52. This small transformer is also used by being mounted on a printed circuit board, and the terminal pins 54 are inserted into holes in the printed circuit board and soldered. (For example, refer to Patent Document 1.)
The structure of this small transformer consists of a cylindrical drum core, a cylindrical or box-shaped ring core that wraps and shields the drum core, a winding wound around the drum core, and a terminal plate that connects the winding start and end of the winding. And is basically the same as the conventional example of FIG.
[0008]
[Patent Document 1]
Japanese Utility Model Publication No. 7-47856 (FIG. 4)
[0009]
[Problems to be solved by the invention]
In the above-described conventional example, the drum core and the ring core are both separate bodies, and are each mounted and fixed on a terminal block or the like. Therefore, there are the following problems. That is, the first problem is that the drum core has a columnar shape as compared with the ring core, and a fixed structure having only one end is vulnerable to impact, vibration, and the like. Particularly in the former conventional example, when the printed circuit board is bent due to an impact due to dropping or the like, the small coil mounted on the printed circuit board touches the circular hole of the ring core and the tip of the drum core swings to the fixing portion with the terminal block. In some cases, stress is applied and this part is broken. In the latter conventional example, since the drum core is supported by the bobbin, the condition is better than the former, but there is a similar problem because there is a gap between the dram core and the bobbin.
[0010]
The second problem is that since the drum core and the ring core are both separate bodies, they need to be separately manufactured, managed, and assembled, so that the cost is high.
[0011]
An object of the present invention is to provide a small-sized coil that is low-cost and resistant to impact and a method of manufacturing the same.
[0012]
[Means for Solving the Problems]
According to a method of manufacturing a small coil of the present invention, in a small coil having a cylindrical drum core, a cylindrical or box-shaped ring core that encloses and shields the drum core, and a terminal plate, the drum core and the ring core are integrally formed. Have been.
Further, the drum core may be integrally formed with a flange portion on a lower surface side opposite to an upper surface integrated with the ring core.
[0013]
The terminal board may be embedded and fixed at one end thereof to a side face of the ring core at the same time when the drum core and the ring core are integrally formed.
[0014]
Further, in the drum core, the flange portion may be separated and attached later.
[0015]
Further, a bottom plate made of the same material as the ring core may be added to the opening of the ring core.
[0016]
Further, a bottom plate made of the same material as the ring core may be added to the opening of the ring core, and the terminal may be embedded and fixed in the bottom plate.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0018]
FIGS. 1A and 1B are a schematic perspective view and a sectional view, respectively, showing a first embodiment of the present invention. FIGS. 2A and 2B are a schematic perspective view and a cross-sectional view showing a second embodiment of the present invention. FIGS. 3A and 3B are a perspective view and a sectional view, respectively, showing a third embodiment of the present invention.
[0019]
First, a first embodiment of the present invention will be described with reference to FIG. A core 1 formed by integrally molding a cylindrical drum core portion 12 having a flange portion 13 and a box-shaped ring core portion 11 that wraps and shields the drum core portion 12, and the drum core portion 12 and the ring core portion 11 are integrally formed. At the same time, it is composed of two left and right terminal plates 2 whose one ends are embedded and fixed on both side surfaces of the ring core 11 and the winding 3 wound around the drum core 12.
[0020]
The material of the core 1 is ferrite, and the material of the terminal plate 2 is a metal piece. This small coil assembling step is a winding step of winding the winding 3 around the drum core 12 of the integrally formed core 1, and the winding 3 is wound directly on the drum core 12. At the time of this winding work, a small dedicated winding machine is used because the flange portion 13 interferes. However, if this small dedicated winding machine cannot be prepared, the following method is used.
[0021]
That is, the flange 3 of the core 1 is attached in advance, and the winding 3 is wound directly on the drum core 12 without the flange 13, or a bobbin is prepared and the winding 3 is wound thereon. The lever bobbin is mounted on the drum core 12. Thereafter, the flange portion 13 is bonded to the drum core portion 12.
[0022]
The end of the wire at the start and end of winding of the winding 3 is welded or soldered to the terminal plate 2.
[0023]
Next, a second embodiment of the present invention will be described with reference to FIG. The difference from FIG. 1 is that a bottom plate is added to the bottom of the core. In this way, leakage of magnetic flux to the outside can be prevented and at the same time the characteristics of the coil can be improved.
[0024]
The core 21 is formed by integrally molding a cylindrical drum core portion 212 having a flange portion 213 and a box-shaped ring core portion 211 that wraps and shields the drum core portion 212, a drum core portion 212 and a ring core portion 211. At the same time, the left and right two terminal plates 22 whose one ends are embedded and fixed on both side surfaces of the ring core portion 211, the windings 23 wound around the drum core portion 212, and the inside for magnetically sealing the inside are formed. And a bottom plate 24 made of ferrite.
[0025]
The assembly process of this small coil is the same as that of FIG. 1, but the bottom plate 24 is bonded to the inner wall of the ring core 212 in the last process.
Next, a third embodiment of the present invention will be described with reference to FIG. The difference from FIG. 2 is that a terminal plate is provided on the bottom plate. By doing so, the strength of the terminal portion can be enhanced.
[0026]
The core 31 is formed by integrally molding a cylindrical drum core 312 having a flange 313 and a box-shaped ring core 311 that encloses and shields the drum core 312, and is wound around the drum core 312. Winding 33, a bottom plate 34 made of ferrite for magnetically sealing the inside, and two right and left terminal plates 32 embedded and fixed on both side surfaces of the bottom plate 34. It is configured.
[0027]
The assembly process of this small coil is the same as that of FIG. 2, and the bottom plate 34 is adhered to the bottom surface of the ring core 312 in the last process. Left and right two terminal boards 32 are embedded and fixed on both side surfaces of the gate 34. The ring core 311 is provided with a cutout through which the lead wire at the beginning and end of the winding 33 is passed, and this lead wire is welded to the terminal plate 33 in the last step.
[0028]
【The invention's effect】
As described above, according to the present invention, a cylindrical drum core and a box-shaped ring core that wraps and shields the drum core are integrally formed and formed, and a terminal plate fixed to or near the opening-side bottom surface of the ring core is provided. Since the shock transmitted to the printed circuit board is received by the ring core because it is a structure that is mounted on a printed circuit board, the fixed part of the ring core that is vulnerable to shock does not receive direct shock, and this part breaks There is an effect that can be prevented.
[0029]
Further, by integrally molding the drum core and the ring core, and simultaneously embedding and fixing the terminal plate to the opening-side bottom surface of the ring core at the time of the integral molding, it is possible to reduce the manufacturing cost.
[0030]
Further, by adding a bottom plate to the bottom of the core, it is possible to prevent the leakage of magnetic flux to the outside and to improve the characteristics of the coil.
[Brief description of the drawings]
FIG. 1A is a schematic perspective view showing a first embodiment of the present invention, and FIG.
FIGS. 2A and 2B are a perspective view and a sectional view, respectively, showing a second embodiment of the present invention.
3A and 3B are a perspective view and a sectional view, respectively, showing a third embodiment of the present invention.
4A is a schematic perspective view showing a conventional example, and FIG.
5A is a schematic perspective view showing another conventional example, and FIG.
[Explanation of symbols]
1, 21, 31 cores 2, 22, 32 terminal plates 3, 23, 33 windings 11, 211, 311 ring cores 12, 212, 312 drum cores 13, 213, 313 flanges 24, 34 bottom plate

Claims (6)

A small coil having a cylindrical drum core, a cylindrical or box-shaped ring core for enclosing and shielding the drum core, and a terminal plate, wherein the drum core and the ring core are integrally formed and manufactured. Method. The method according to claim 1, wherein the drum core is integrally formed with a flange portion on a lower surface opposite to an upper surface integrated with the ring core. 3. The method for manufacturing a small coil according to claim 1, wherein said terminal plate is embedded and fixed at one end thereof to a side surface of said ring core when said drum core and said ring core are integrally formed. The method for manufacturing a small coil according to claim 2, wherein the drum core separates and attaches the flange portion. 5. A small coil manufactured according to claim 1, wherein a bottom plate made of the same material as the ring core is added to an opening of the ring core. 5. The manufacturing method according to claim 1, wherein a bottom plate made of the same material as the ring core is added to an opening of the ring core, and the terminal is embedded and fixed in the bottom plate. Small coil.

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