JPH11111535A - Surface mount inductor with perforated magnetic core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide simplicity and space-saving of a coil and facilitate production, by winding the coil so as to pass through a through-hole in place of a perforated ferrite core, and electrically connecting the coil by directly annexing a connecting terminal in place of the perforated ferrite core. SOLUTION: A coil 2 is wound around a core intermediate portion 13 of a perforated ferrite core 1, and a solderless terminal 3 is fitted into both core ends of the perforated ferrite core 1 to electrically connect both ends of the coil 2, respectively. The perforated ferrite core 1 is juxtaposed with two circular through-holes 12 concentric to an arc of both end faces at both sides of an elliptical ferrite piece. The coil 2 is passed into both through-holes 12 and wound around the core intermediate portion 13 between both holes of the perforated ferrite core 1 with about several turns to more than ten turns. The coil is directly wound around the ferrite core 1 since it has electrical insulating performance. The solderless terminal 2 is also directly fitted to the coil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount inductor having a perforated magnetic core.

[0002]

2. Description of the Related Art An inductor with a magnetic core, in which a coil made of a thin copper wire is wound around a rod-shaped ferrite core, is already well known as exhibiting a higher inductance than an air-core inductor. It is often used for equipment. In recent years, an inductor using a spectacle-shaped core for an inductor containing a magnetic core has been developed, and the performance has been remarkably improved.

[0003]

However, the following problems have been pointed out in these conventional inductors. For example, in the case of 30μH, the air-core inductor is large and easy to make,
In any case, the height cannot be less than 2 mm. In an inductor with a magnetic core using a rod-shaped ferrite core, it is possible to reduce the height to 2 mm or less in the inverted posture.
A coil of about a turn must be carefully wound around three layers with very thin windings without any gaps.
The cost is high. In addition, the resistance value increases, and the power loss increases. In a magnetic core-containing inductor using an eyeglass-type core, the number of coils can be reduced to about 10 turns, the resistance value can be correspondingly reduced, and power loss can be reduced. However, using a terminal plate having pin terminals protruding from both sides of the insulating plate as a base, an eyeglass-shaped core is erected from the upper surface of the insulating plate, and a coil wound around the eyeglass-shaped core is applied to those pin terminals. Due to the electrical connection, the height cannot be reduced to 2 mm or less, and the surface cannot be directly mounted on a printed wiring board or the like as it is, which is extremely inconvenient in use. The present invention is intended to eliminate these problems of the conventional product, and by using a perforated ferrite core, simplification, space saving, and the like can be achieved, so that surface mounting on a printed wiring board or the like can be achieved. In addition, it is intended to make the production easier, improve the yield, shorten the production time, reduce the cost, and minimize the damage caused by external force even if a brittle ferrite core is used. .

[0004]

In order to achieve the above-mentioned object, the invention according to claim 1 is directed to a perforated ferrite core 1 having one or several through holes 12 and a magnetic path formed around the through holes. Is established,
The coil 2 is wound by inserting the perforated ferrite core into an appropriate place of the perforated ferrite core 12, and a connection terminal is directly provided at an appropriate place of the perforated ferrite core 1 to electrically connect the coil 2. It is characterized by having.

According to the second aspect of the present invention, there is provided an eyeglass-shaped perforated ferrite core 1 in which two circular through holes 12 are juxtaposed in a small elliptical ferrite piece 11. The coil 2 is wound around the core intermediate portion 13 between the two through-holes by passing through the two through-holes.
Cap-shaped or ring-shaped crimp terminals 3 are fitted to both ends of the core, respectively, and both ends of the coil 2 are electrically connected to the respective crimp terminals.

According to a third aspect of the present invention, there is provided an eyeglass-shaped perforated ferrite core 1 in which two circular through-holes 12 are juxtaposed in a small elliptical ferrite piece 11. The coil 2 is wound around the core intermediate portion 13 between the two through-holes by passing through the two through-holes.
Chip terminals 4 are respectively attached to both ends of the core on one surface, and conductive pins 41 are erected from each chip terminal and inserted into the respective through holes 12, and both ends of the coil 2 are attached to the tip of each conductive pin 41. Are electrically connected to each other.

In each of the above-mentioned inventions, the size of the perforated ferrite core 1 is 5 mm inside and outside width, 3 mm inside and outside depth, 1 mm inside and outside thickness, and hole diameter or 1 mm inside and outside. Corresponding.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

1. 1. FIGS. 1 and 2 show an embodiment according to the first and second aspects of the present invention. 1 and 2, 1 is
An eyeglass-shaped perforated ferrite core, 2 is a coil wound around a core intermediate portion 13 of the perforated ferrite core, 3
Are crimp terminals (connection terminals) which are fitted to both ends of the perforated ferrite core 1 and electrically connect both ends of the coil 2 respectively. The perforated ferrite core 1 is shown in FIGS.
As shown in the figure, two circular through-holes 12 having a diameter of 1 mm concentric with the arcs of both end faces at both ends are arranged side by side on a small elliptic ferrite piece 11 having a width of 5 mm, a depth of 3 mm and a thickness of 1 mm. ing. Note that the size is not limited to this, and large and small changes are allowed as long as the size is within the range. The coil 2 has a wire diameter of 0.1
Using two kinds of PEW wires of 1 mm, several turns to several tens of turns are inserted through the through holes 12 and into the core intermediate portion 13 between the two holes of the perforated ferrite core 1. Since the ferrite core has an electric insulating property, it may be wound directly. The crimp terminal 3 may be directly fitted. The crimping terminal 3 is formed in a rectangular parallelepiped cap shape corresponding to the end of the perforated ferrite core 1 by a conductive material (metal), and a small hole 31 is formed in a side surface. The ferrite core 1 is fixed to the end of the perforated ferrite core 1 by fitting and pressing. Further, the winding end of the coil 2 is sandwiched inside, and the tip is inserted through the small hole 31 to perform soldering 32. As shown in FIGS. 3 and 4, a small hole 31 may be formed in the upper surface, and the winding end may be soldered 32 at this portion.

A trial production of the coil 2 with 10 turns was performed and the test was as follows. The comparative sample was 5.0 ×
Two types of PEW wires having the same wire diameter of 0.11 mm as the above-mentioned windings were formed on a 2.0 × 0.6 mm rectangular rod-shaped ferrite core in three layers by 6 layers.
It is wound 0 turns. The outer shape is 5.0 ×
It was 2.7 x 1.5 mm.

[0010]

[Table 1]

[0011]

[Table 2] As described above, the sample of the present invention requires only about 1/6 the number of turns of the coil and about 1/10 of the winding length as compared with the comparative sample, and can further increase the inductance value and the winding resistance value. It became clear that it could be much smaller. It was also found that the form can be reduced in size, and the height is 1.5 mm or less in a mounting state, that is, a lying state.

In the above embodiment, the perforated ferrite core 1 is of an eyeglass type, but may be of an EI type or the like. Further, although the crimp terminal 3 is formed in the shape of an oblong rectangular cap, it may be formed in a ring shape.

FIG. 5 shows an embodiment according to the first and third aspects of the present invention. In the case of FIG. 5, FIG.
2, the connection terminals are different. That is,
Chip terminals 4 are attached to both ends of the core on the lower surface of the perforated ferrite core 1, and conductive pins 41 each having a head are erected from each chip terminal so as to be able to conduct electricity, and are inserted into the respective through holes 12. The two ends of the coil 2 are wound around the ends of the conductive pins 41 to be electrically connected to each other, and a perforated ferrite core 1 is provided between the two chip terminals 4 and an insulating material 5 is applied to the lower surface of the coil 2. doing.

[0014]

According to the first, second, and third aspects of the present invention, the following advantages are achieved because of the configuration described above. (1) Since the coil 2 and the connection terminals are directly attached using the perforated ferrite core 1 with high electrical insulation performance, it can be directly surface-mounted on a printed wiring board, etc., and can be downsized and simplified. Thus, the height can be suppressed to 1.5 mm or less, space can be saved, and it can be conveniently used for a small communication device or the like. (2) Since the inductance value of the coil can be remarkably increased, the number of turns can be reduced to several turns to several tens of turns, which can be reduced to about 1/6 of the conventional one, and the length of the winding used can be reduced to 1 / It can be reduced to about 10. (3) Since the number of turns of the coil and the length of the coil are extremely small as compared with the conventional case, the resistance value can be remarkably reduced, and it is possible to contribute to the power saving of the installed device. (4) Since the number of windings of the coil is extremely small as compared with the conventional case, the winding operation is much easier than conventionally carefully winding up several layers, and the breakage of the winding during the operation can be reduced. (5) The mounting of the connection terminals is easy, and as a whole, the production is extremely simple and easy, and the production can be made almost without any trouble. (6) Overall, production time can be greatly reduced and costs can be reduced.

Further, according to the second and third aspects of the present invention, (a) the crimp terminal 3 or the chip terminal 4 facilitates assembly, and can be reduced in size and simplified. (b) Perforated ferrite core 1, two round through-holes 12 are formed side by side on small elliptic ferrite pieces 11 to form eyeglasses, and are not square, and use brittle ferrite cores. Nevertheless, damage due to external force can be minimized.

[Brief description of the drawings]

FIG. 1 is an enlarged plan view showing a first embodiment of a micro inductor with a magnetic core according to the first and second aspects of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an enlarged plan view showing a modification of the first embodiment of FIGS. 1 and 2 according to the first and second aspects of the present invention.

FIG. 4 is a sectional view taken along line BB of FIG. 3;

FIG. 5 is an enlarged central vertical sectional front view showing Embodiment 2 of the micro inductor with a magnetic core according to the first and third aspects of the present invention.

FIG. 6 is an enlarged plan view showing a perforated ferrite core of a used member.

FIG. 7 is a sectional view taken along line CC of FIG. 6;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Perforated ferrite core 11 ... Small piece of ferrite 12 ... Through hole 13 ... Core intermediate part 2 ... Coil 3 ... Connection terminal 31 ... Small hole 32 ... Soldering 4 ... Chip terminal 41 ... Conductive pin 5 ... Insulation material

Claims (3)

[Claims] 1. A perforated ferrite core 1 in which one or several through holes 12 are formed to form a magnetic path around the perforations, and the perforated ferrite cores are inserted into appropriate places of the perforated ferrite cores. Then, the coil 2 is wound, and the perforated ferrite core 1
3. A surface-mounted inductor with a perforated magnetic core, wherein a connection terminal is directly provided at an appropriate position to electrically connect the coil 2. 2. A ferrite core 1 formed in a spectacle shape by arranging two circular through-holes 12 in parallel in a small piece 11 of an oblong ferrite, and between the two through-holes of the perforated ferrite core. The coil 2 is wound around the core intermediate portion 13 by being inserted into both through holes, and cap-shaped or ring-shaped crimp terminals 3 are fitted to both ends of the core of the perforated ferrite core 1, respectively. A surface-mounted inductor with a perforated magnetic core, wherein both ends of the coil 2 are electrically connected to terminals. 3. A ferrite core 1 formed in a spectacle shape by arranging two circular through-holes 12 side by side on a small elliptical ferrite piece 11, and between the two through-holes of the perforated ferrite core. The coil 2 is wound around the core intermediate portion 13 by being inserted into both through holes, and chip terminals 4 are attached to both ends of the core of the perforated ferrite core 1 respectively. 41. A surface-mounted inductor with a perforated magnetic core, wherein an upright 41 is inserted through each of the through holes 12 and both ends of the coil 2 are electrically connected to the ends of the conductive pins 41, respectively.