JPS6238847B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a chip-shaped fixed inductor in which electrodes are surface-connected to a circuit pattern on a substrate.

In recent years, with the miniaturization of electronic components, so-called chip-shaped high-frequency coils, especially fixed inductors, that are surface-connected to circuit patterns on plastic or ceramic substrates are being used, but the size of these coils ranges from 5 mm on a side. It has a very small shape that can fit into a 4mm cube. The electrodes are formed by adhering a linear or plate-shaped metal piece to the flange of the core, or by printing or vapor depositing silver or the like.

FIG. 1 shows a front view of an example of a conventional fixed inductor. The electrode 1 is a plate-shaped metal piece with an L-shaped cross section, and is fixed to the lower flange 3 of the drum core 2 with adhesive. There is. This electrode 1 is then solder-dipped and soldered directly to the circuit pattern. However, in the current situation where the thickness of the lower tsuba 3 is 1 mm or less and the height H of the electrode 1 is also about 0.5 mm,
In terms of solder wetting, the electrode 1 is not much different from one in which the side surface 4 is not substantially present and the electrode 1 is formed in a flat plate shape only on the bottom surface 5 of the lower flange 3. If the side surface 4 of the electrode 1 is not soldered and the circuit pattern is connected only to the portion located on the bottom surface of the lower flange 3, the reliability of the connection of the electrode 1, which is already small in shape, is significantly reduced.

Front view and top view of Figure 2 a, b, Figure 3 a, b
The front view and top view of FIG. 4A and FIG. condition can be improved.

In Figures 2a and b, 6 is a ferrite drum core, 7 is an electrode, 8 is a winding wire, 9 is a winding part, 10,
Reference numerals 11 denote the upper and lower flange of the drum core 6, respectively. The upper flange 10 and the lower flange 11 are circular in shape and have the same size. The two electrodes 7 are each formed of a metal piece in the shape of a flat plate bent into a U-shape, and are fixed using adhesive at opposite positions sandwiching the upper and lower collars 10 and 11 from above and below. . The lower surface 12 of the electrode 7 is longer than the upper surface 13 and is bent inward. The leads of the winding 8 wound around the winding part 9 are connected to the electrode 7 by soldering or welding as described later, and the lower surface 12 of the electrode 7
is placed on the circuit pattern of the board and soldered.

In FIGS. 3a and 3b, the upper flange 15 of the drum core 14
The shapes of the lower tsuba 16 and the lower tsuba 16 are squares of the same size.
The electrode 17 is formed of a U-shaped metal piece made by bending a flat plate to the same length on both the upper and lower sides, and is fixed by sandwiching the upper flange 15 and the lower flange 16 from above and below. Step portions 20 are formed at opposite ends of the surface 18 of the upper flange 15 sandwiched between the electrodes 17 and at opposite ends of the surface 19 of the lower flange 16, respectively. Step portion 20, surface 18, and step portion 20
The horizontal positions of the surfaces 19 and 19 differ approximately by the thickness of the electrodes 17, and the electrodes 17 touch the upper flange 1 at this stepped portion 20.
By sandwiching 5 and lower tsuba 16, surface 18 and surface 1 are formed.
Surface 21, surface 18, and surface 19 of electrode 17 located at 9
The horizontal positions of are kept the same.

In FIGS. 4a and 4b, the upper flange 23 and lower flange 24 of the drum core 22 have the same circular shape. The electrode 25 is formed of a metal piece that is made by bending a flat plate into a U-shape on the upper and lower sides, but the lower side has two steps in the shape of a step.
It is folded into steps. The upper flange 23 and the lower flange 24 are sandwiched between the stepped portion 26 and the upper surface 27 of the electrode 25. The side surface 28 of the electrode 25 is not in contact with the side surfaces of the upper flange 23 and the lower flange 24, and the electrode 25
5, the winding 8, and the drum core 22 are wider than those in FIGS. 2a, b and 3 a, b. By filling this space with a synthetic resin 30 mixed with oxide magnetic powder, for example, ferrite, the magnetic flux caused by the current flowing through the winding 8 forms a closed magnetic path. The stair portion 26 of the electrode 25 and the bottom surface of the lower flange 24 where the stair portion 26 does not exist are filled with a synthetic resin 29 for reinforcing the fixed state of the electrode 25. The lower surface 31 of the electrode 25 excluding the stepped portion 26 is placed on the circuit pattern and soldered. Note that if it is not necessary to form a closed magnetic path, the space can be filled with the same synthetic resin 29 instead of the synthetic resin 30 mixed with oxide magnetic material to strengthen the overall structure of the fixed inductor.

In such a fixed inductor, the electrodes are formed vertically and continuously by sandwiching the flanges at both ends of the winding part, so that the side surfaces can be formed as long as about 3 mm to 4 mm. Therefore, soldering is sufficiently performed not only on the lower surface but also on the upper surface and side surfaces, thereby improving the reliability of connection with the circuit pattern.

The present invention provides a method of manufacturing a fixed inductor as described above.

The present invention provides a method for manufacturing a fixed inductor in which electrodes are formed by plate-shaped metal pieces inserted between the flanges at both ends of the winding portion of the core from above and below, and the leads of the winding are connected to the electrodes. A fixed inductor characterized in that a wire is wound around a core with a metal piece fixed to one side of the collar, and then the leads of the winding are connected to the metal piece, and then the metal piece is bent and fixed to the remaining collar. It is in the manufacturing method.

The following description will be made with reference to FIGS. 5a and 5b, FIGS. 6 and 7, which are process diagrams showing examples of the manufacturing method of the present invention.

First, as shown in the bottom and front views of FIGS. 5a and 5b, a T
One end 33 of the letter-shaped plate-shaped metal piece 34 is fixed with adhesive. In this state, the winding 8 is wound around the winding portion 9 of the drum core 35. Furthermore, as shown in the front view of FIG. 6, the lead 37 of the winding 8 is connected to the tapered portion 40 of the metal piece 34 by welding or soldering. When soldering, it may be done after tying the tapered portion 40 of the metal piece 34.

Next, as shown in the front view of FIG. 7, the tapered portion 40 of the metal piece 34 is bent upward at a substantially right angle and again horizontally along the upper flange 38. Then, a metal piece 34 is fixed in the same manner as the bottom surface 32 at a portion located above the upper flange 38, and an electrode sandwiching the upper flange 38 and the lower flange 36 is formed, thereby completing a fixed inductor. If the inside of the electrode is to be filled with synthetic resin for the purpose of forming a closed magnetic path or to strengthen the structure of the entire fixed inductor, it is preferable to use a mold after this. Note that the metal piece 34 is attached to the drum core 35.
As shown in the bottom view of the drum core in FIG. 8, a metal film 39, for example silver, is printed and baked, one end 33 of the metal piece 34 is welded to this metal film 39, and then the top If the same is applied to the collar 38, the metal piece 34 can be fixed to the drum core 35 without using adhesive.

According to the manufacturing method of the present invention, when the winding wire 8 is wound, the metal piece 34 is still simply a flat plate, and there is no inconvenience to the winding work, and the lead 37 and the metal piece 34
Since the metal piece 34 remains a flat plate even when the metal pieces 34 are connected, the connection is easy.

Although the shape of the metal piece varies depending on the method of connection with the lead 37 and other purposes, and the shape of the drum core also varies, it is clear that this advantage remains unchanged and contributes to reducing the number of man-hours during manufacturing.

[Brief explanation of the drawing]

Figure 1 is a front view of a conventional fixed inductor, Figure 2 is a front view of a conventional fixed inductor.
Figures a and b are a front view and a top view of a fixed inductor to which the present invention can be applied, Figures 3 a and b are a front view and a top view of another fixed inductor to which the present invention can be applied, and Figure 4
Figures a and b are a front view and a top view of still another fixed inductor to which the present invention can be applied;
7 and 7 are process diagrams showing an embodiment of the manufacturing method of the present invention, and FIG. 8 is a bottom view of the drum core. 1, 7, 17, 25...electrode, 2, 6, 14,
22, 35...Drum core, 3, 11, 16, 2
4, 36... lower tsuba, 4, 28... side, 5, 32
... Bottom surface, 8 ... Winding wire, 9 ... Winding part, 10, 1
5, 23, 38... upper tsuba, 12, 31... lower surface, 13, 27... upper surface, 18, 19...
Surface, 20... Step portion, 21... Surface, 29... Synthetic resin, 30... Synthetic resin containing powder of oxide magnetic material, 33... One end, 34... Metal piece, 37...
Lead, 39... Metal film, 40... Tapered part.

Claims (1)

[Claims] 1. In a method for manufacturing a fixed inductor, the electrodes are formed by plate-shaped metal pieces inserted between the flanges at both ends of the winding part of the core from above and below, and the leads of the winding are connected to the electrodes. A fixed inductor is manufactured by winding a winding wire around the core while fixing it to one side of the collar, then connecting the leads of the winding to a metal piece, bending the metal piece, and fixing it to the remaining collar. Method.