JP2003217936A - Coil component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coil component that is hard to saturate magnetically and is improved in reliability, even when its upper and lower sides are made thin to reduce the profile. <P>SOLUTION: Thickness (W) of an outer case 3 enclosing the coil 2 is made smaller than the diameter of the through-hole 1 for the coil 2. The density in the upper part 11 of the outer case 3 for the upper part of the coil 2 and the lower part 12 of the case 3 for the lower part of the coil 2 is made larger than that of the middle part 13 of the case 3. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil component used in various consumer appliances and the like.

[0002]

2. Description of the Related Art A conventional coil component will be described below with reference to the drawings.

FIG. 9 is a perspective view of a conventional coil component, and FIG.
Is a sectional view, and FIG. 11 is a sectional view showing a part of the manufacturing process.

As shown in FIGS. 9 to 11, a conventional coil component is connected to a coil portion 52 having a through hole 51, an exterior portion 53 made of a magnetic material containing the coil portion 52, and the coil portion 52. In addition, the external part 53 is provided with a terminal 54 protruding from the external part 53, and the external part 53 is formed by press-molding the magnetic powder 55 so as to cover the coil part 52.

A constant molding pressure is applied to the exterior portion 53 as a whole, and the density of the exterior portion 53 is substantially the same. In addition, 59 is a metal mold | die.

[0006]

SUMMARY OF THE INVENTION In the above conventional configuration,
In order to reduce the height, it is necessary to increase the molding pressure applied to the exterior portion 53 and to condense the exterior portion 53 over the entire surface.

However, although the height is reduced in accordance with the condensation of the exterior portion 53, the upper surface portion and the lower surface portion of the exterior portion 53 become thin, and the magnetic flux passing through the through hole of the coil portion 52 has the exterior portion 5.
When passing through the upper surface portion and the lower surface portion of No. 3, magnetic saturation is likely to occur and reliability is deteriorated.

In order to solve the above problems, the present invention provides a coil component with improved reliability, in which magnetic saturation is unlikely to occur even if the upper surface portion and the lower surface portion are thinned in order to reduce the height. It is an object.

[0009]

In order to achieve the above object, the present invention has the following constitution.

In the invention according to claim 1 of the present invention, in particular, the exterior part is a dust core containing magnetic powder, and the upper part corresponding to the upper part of the coil part and the lower part of the coil part. With a lower surface portion corresponding to the portion, and an intermediate portion corresponding to the height portion of the coil portion, while making the inclusion thickness dimension of the coil portion smaller than the diameter of the through hole of the coil portion, The density of the upper surface portion and the density of the lower surface portion are made higher than the density of the intermediate portion.

With the above structure, the outer casing corresponding to the upper portion of the coil portion is provided until the inner thickness of the coil portion (the distance between the coil portion and the surface of the outer casing portion) becomes smaller than the diameter of the through hole of the coil portion. Even if the upper surface of the upper portion and the lower surface of the outer portion corresponding to the lower portion of the coil are formed thin to reduce the overall height, the density of the upper surface and the density of the lower surface are lower than the density of the intermediate portion. Since it is made large, it is possible to suppress the occurrence of magnetic saturation in the upper surface portion and the lower surface portion.

That is, the inside of the through hole of the coil portion corresponds to the intermediate portion of the exterior portion, but since the density of the upper surface portion and the lower surface portion of the exterior portion is higher than the density of this intermediate portion, the through hole Even if the magnetic flux passing through the inside passes through the upper surface and the lower surface that are smaller than the diameter of the through hole, the magnetic permeability can be increased in the upper surface and the lower surface because the density is higher than that in the intermediate area. The height can be reduced without causing magnetic saturation in the lower part and the lower part.

In the invention according to claim 2 of the present invention, in particular, the intermediate portion is an inner intermediate portion corresponding to the inside of the through hole of the coil portion,
The outer peripheral portion of the outer peripheral surface of the coil portion has an outer intermediate portion, and the outer intermediate portion has a higher density than the inner intermediate portion.

With the above structure, the outer intermediate portion can have a higher magnetic permeability as much as the inner intermediate portion has a higher density, the lateral dimension can be reduced without causing magnetic saturation in the outer intermediate portion, and the outer intermediate portion can be mounted. Time saving can be achieved.

In the invention according to claim 3 of the present invention, in particular, in the exterior part, the density of the upper surface part and the density of the lower surface part are from 5.0 to 5.0.
The density of the intermediate portion is 6.0 g / cm ^3, and the density of the middle portion is 85% to 98% of the density of the upper surface portion and the lower surface portion.

With the above structure, it is possible to suppress the breakage of the coil portion while preventing the breakage of the coil portion, and the breakage of the exterior portion itself due to the internal stress or the like. In addition, it is possible to suppress the occurrence of magnetic saturation and achieve size reduction.

In the invention according to claim 4 of the present invention, in particular, the coil portion is an edgewise winding in which a rectangular wire is wound, and the coil portions are adjacent to each other so that an exterior portion is not formed between the adjacent rectangular wires. It is a structure in which the rectangular wire is closely attached.

With the above construction, since the coil portion is an edgewise winding, the space factor can be improved and a large current can be accommodated. In particular, since the adjacent rectangular wires are in close contact with each other, no exterior part is formed between the rectangular wires, so that it is possible to suppress the generation of magnetic flux circulating around the rectangular wires and reduce the loss.

In the invention according to claim 5 of the present invention, in particular, in the exterior part, the binder containing the thermosetting resin and the magnetic powder are mixed in an unheated state in which the thermosetting resin is not completely cured. The pressure-molded green compact is re-pressure-molded so as to cover the coil portion and is heated and molded so that the thermosetting resin is completely cured.

With the above structure, a mold is generally used for pressure molding, but since the powder compact becomes a solid material, the amount of powder compact between the mold and the coil portion is re-pressure molded. Sometimes it does not fluctuate, the coating thickness of the exterior part is likely to be uniform over the entire circumference of the coil part, characteristic variations can be suppressed, and the coil part can be supported by the green compact itself, so the coil part can be positioned accurately. It is possible to prevent defective molding of the exterior part.

According to the sixth aspect of the present invention, in particular, the thermosetting resin is a silicone resin having a high hardness resin component and an elastic resin component.

Since a silicone resin having a high hardness resin component and an elastic resin component is used as the thermosetting resin,
It is possible to form an exterior part having a strength that balances hardness and brittleness, and reduce defects in the exterior part.

In the invention according to claim 7 of the present invention, in particular, the green compact is provided with a weak hardness portion having a hardness that the shape of the green compact collapses during re-press molding, and 2
The compact is individually molded, and the compact is re-pressure-molded so that the weak hardness portion of the compact covers the coil portion.

With the above-mentioned structure, the green compact is provided with a weak hardness portion having a hardness such that the shape of the green compact collapses during re-pressure molding, and the weak hardness portion covers the coil portion. Since it is re-pressure-molded, the coil part can be accurately covered, the gap between the green compact and the coil part can be filled without any gap, and the magnetic gap can be reduced to improve the magnetic efficiency. be able to.

In the invention according to claim 8 of the present invention, in particular, when the re-pressure molding is performed on the green compact, when the re-pressure molding is performed, the hard portion having a hardness that does not cause the shape of the green powder to collapse. And a weak hardness portion having a hardness in which the shape of the green compact is broken, and the exterior portion supports at least one of the strong hardness portions of the green compact supporting one surface of the coil portion, and the weak hardness portion includes the coil. Re-press molding the green compact so as to cover the other surface of the part,
In addition, the thermosetting resin is heat-molded so as to be thermoset.

With the above structure, since the hard portion of the green compact firmly supports the one surface of the coil portion, the coil portion is less likely to be displaced during re-pressure molding, and the coil portion can be positioned accurately. The weak hardness part of the green compact can easily cover the other surface of the coil part while destroying its shape.
It is easy to make the coating thickness of the exterior part uniform over the entire circumference of the coil part, and it is possible to suppress characteristic variations.

Further, since the weak hardness portion of the deformed green compact covers the coil portion accurately, it is possible to fill the green compact without any gap between the coil portion and the green compact. The magnetic gap can be reduced and the magnetic efficiency can be improved.

In the invention according to claim 9 of the present invention, in particular, the shape of the green compact is a cross section E having a middle leg portion and an outer leg portion on the back surface.
In the configuration, the back surface portion is formed into a character shape, the back surface portion is formed into a high hardness portion, and the middle leg portion and the outer leg portion are formed into a weak hardness portion.

With the above structure, the hardened portion of the green compact is less likely to be displaced, the other surface of the coil portion can be easily covered, and variations in characteristics can be suppressed.

The invention according to claim 10 of the present invention is
One of the green compacts and the other green compact are re-pressure-molded so that the back surface of the hardened portion supports one surface of the coil portion.

With the above-mentioned structure, it is possible to prevent the positional deviation from occurring more easily with respect to the strong hardness portion of the green compact, and to easily cover the end surface of the coil portion and suppress the characteristic variation.

The invention according to claim 11 of the present invention is
One of the green compacts was made to have the back surface of the hardened portion support one surface of the coil part, and the other green compact was formed by inserting the middle leg into the through hole of the coil part and re-press-molded. It is a composition.

With the above structure, the displacement of the hard hardness portion of the green compact is less likely to occur, the other surface of the coil portion can be easily covered, and variations in characteristics can be suppressed.

The invention according to claim 12 of the present invention is
Re-pressurization is performed by providing minute concave and convex portions on the tips of the middle leg and the outer leg of the two green compacts, and by making the middle leg and the outer leg of the two green compacts face each other. It is a molded configuration.

With the above structure, it is possible to prevent the positional deviation from occurring more easily with respect to the strong hardness portion of the green compact, and it is possible to easily cover the other surface of the coil portion and suppress variations in characteristics.

The invention according to claim 13 of the present invention is particularly
This is a structure in which a dividing groove for dividing is provided on the back surface of the green compact.

With the above structure, since the green compact is divided by the dividing groove at the time of re-press molding, the other surface of the coil portion can be easily covered and variation in characteristics can be suppressed.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION A coil component according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a coil component according to an embodiment of the present invention, FIG. 2 is a perspective view thereof, FIG. 3 is a diagram showing a part of the manufacturing process, and FIG. FIG. 5 is a perspective view of the body, FIG. 5 is a perspective view of a coil portion to which terminals, which are the main parts, are connected, and FIG. 6 is a perspective view before forming the terminals, which are the main parts.

As shown in FIGS. 1 to 6, the coil component in one embodiment of the present invention has a height of 2 to 5 mm and a length of 10 m.
A coil part 2 having a size of an m-square and having a through hole 1, an exterior part 3 including the coil part 2, a terminal 4 connected to the coil part 2 and protruding from the exterior part 3. Is equipped with.

The exterior part 3 is a powder magnetic core (dust core) containing magnetic powder, and a binder containing a thermosetting resin which is a silicon resin having a high hardness resin component and an elastic resin component. And magnetic powder are mixed in a non-heated state in which the thermosetting resin is not completely cured, and 0.5 to 2.0 t
/ A cm ² green compact 5 which is molded under pressure, as a thermosetting resin as well as re-pressed at 3.0～5.0T / cm ² so as to cover the coil portion 2 is completely cured 100 ~ 1
It is formed by heating at 80 ° C.

This dust core uses a heat-treated soft magnetic alloy powder as the magnetic powder, has an average particle size of 1 μm to 100 μm, and its composition is 1 wt.
% ≦ component A ≦ 7 wt% (component A is silicon (Si),
At least one of aluminum (Al), titanium (Ti), and magnesium (Mg) is included), 2 wt% ≤ chromium (Cr) ≤ 8 wt%, 0.05 wt% ≤ oxygen (O)
≦ 0.6 wt%, 0.01 wt% ≦ manganese (Mn) ≦
0.2 wt%, 0.005 wt% ≤ carbon (C) ≤
0.2 wt% and the balance iron (Fe) (instead of the component A, 2 wt% ≦ nickel (Ni) ≦ 15w
It may be t%).

Further, two green compacts 5 are used, and the green compact 5 is re-pressure-molded with a strong hardness portion whose hardness does not collapse during re-pressure molding. A pot type having an E-shaped cross section in which the green compact 5 has a weak hardness portion where the shape of the green compact collapses, and the green compact 5 has a rear part 6 and an inner leg part 7 and an outer leg part 8. The back surface portion 6 is made a strong hardness portion, and the middle leg portion 7 and the outer leg portion 8 are made a weak hardness portion. The weak hardness portion and the strong hardness portion are formed by a portion where the density of the green compact is reduced (weak hardness portion) and a portion where the density is increased (strong hardness portion). The weak hardness portion has a hardness such that the shape is broken by the pressure of several kg / cm ² .

Here, the hardness that the shape of the green compact 5 is broken means that the green powder is broken by the particle size of the magnetic powder. The state of collapse is not included in the range of the hardness of the magnetic powder because it does not collapse due to the particle size of the magnetic powder.

In the exterior part 3, the hard parts of both of the one green compact 5 and the other green compact 5 support one surface (upper and lower surfaces) of the coil part 2 with each other and are weak. The compact is re-press-molded so that the hardness portion covers the other surface of the coil portion 2 (the outer peripheral surface and the inner wall surface of the through hole 1), and is heated so that the thermosetting resin is completely cured. is there.

At this time, the outer casing 3 has an inner casing thickness dimension (W) for enclosing the coil portion 2 smaller than the diameter of the through hole 1 of the coil portion 2 so as to correspond to the upper portion of the coil portion 2. Of the upper surface portion 11, the lower surface portion 12 of the exterior portion 3 corresponding to the lower portion of the coil portion 2, and the intermediate portion 13 of the exterior portion 3 corresponding to the height portion of the coil portion 2, The density of the lower surface portion 12 is made higher than that of the intermediate portion 13.

In particular, the intermediate portion 13 includes an inner intermediate portion 15 corresponding to the inside of the through hole 1 of the coil portion 2 and an outer intermediate portion 14 corresponding to an outer portion of the outer peripheral surface of the coil portion 2, the outer intermediate portion 14 being the outer intermediate portion 14. Is set to be higher than the density of the inner intermediate portion 15.

Regarding these densities, the density of the upper surface portion 11 and the density of the lower surface portion 12 are 5.0 to 6.0 g / cm ^3.
And the density of the intermediate portion 13 is set to the density of 85% to 98%.

In the method of manufacturing the coil component, the exterior portion forming step of enclosing the coil portion 2 in the exterior portion 3 made of a magnetic material, and the terminal 4 protruding from the exterior portion 3 while being connected to the coil portion 2 are formed. And a terminal forming step.

In the step of forming the exterior portion, first, the binder containing the thermosetting resin, which is a silicon resin having a high hardness resin component and an elastic resin component, and the magnetic powder are prevented from completely curing the thermosetting resin. A step of forming two green compacts 5 by mixing and pressing under a non-heated state is provided.

At this time, the green compact 5 has a shape of a pot having an E-shaped cross section having a back portion 6 having a middle leg portion 7 and an outer leg portion 8, and the back portion 6 is repressurized. In addition to forming a hard portion having a hardness that does not cause the shape of the green compact 5 to be collapsed during molding, the middle leg and the outer leg are made to have a weak hardness portion in which the shape of the green compact is collapsed during re-pressure molding. ing.

Next, the strong hardness portions of the two green compacts 5 support one surface (upper and lower surfaces) of the coil portion 2 to each other, and the weak hardness portion of the other surface of the coil portion 2 (the outer peripheral surface and the through hole 1). The outer surface 3 is formed by re-pressurizing and molding the green compact 5 so as to cover the inner wall surface of the
Is provided.

At this time, the backside portions 6 of the two green compacts 5 support the coil portion 2, and the two dies 9 form the middle leg portion 7 and the outer magnetic leg 8 of the weak hardness portion of the green compact 5. And the other surface of the coil portion 2 (the outer peripheral surface and the inner wall surface of the through hole 1) is covered and pressed while breaking the weak hardness portion of the green compact 5.

Particularly, in this case, the back surface portion 6 of the powder compact 5 facing the other surface of the coil portion 2 (the inner wall surface of the through hole 1).
The (hard hardness portion) is embedded in the through hole 11 of the coil portion 2 in a block manner, and the back surface portion 6 (hard hardness portion) of the green compact 5 facing the terminal 4 is blocked toward the terminal 4. While burying it, the middle leg portion 7 (weak hardness portion) and the outer leg portion 8 (weak hardness portion) of the powder compact 5 collapse, and the other surface of the coil portion 2 (the outer peripheral surface and the inner wall surface of the through hole 1). ) Is covered.

Further, in this exterior part forming step, the inner package thickness dimension (W) for enclosing the coil part 2 is set to the through hole 1 of the coil part 2.
And the density of the upper surface portion 11 of the exterior portion 3 corresponding to the upper portion of the coil portion 2 and the density of the lower surface portion 12 of the exterior portion 3 corresponding to the lower portion of the coil portion 2 of the coil portion 2. Intermediate part 13 of the exterior part corresponding to the height part
The step of increasing the density is set.

Further, the intermediate portion 13 is provided with an inner intermediate portion 15 corresponding to the inside of the through hole 1 of the coil portion 2 and an outer intermediate portion 14 corresponding to the outer portion of the outer peripheral surface of the coil portion 2, and the outer intermediate portion is provided. There is also provided a step of making the density of the portion 14 higher than the density of the inner intermediate portion 15.

In the exterior portion 3, the density of the upper surface portion 11 and the density of the lower surface portion 12 are set to 5.0 to 6.0 g / cm ^3, and the density of the intermediate portion 13 is set to 85% to 98% thereof. I am trying.

According to the above-described structure and method, the thickness (W) of the inner package that encloses the coil portion 2 (the distance between the coil portion 2 and the surface of the exterior portion 3) becomes smaller than the diameter of the through hole 1 of the coil portion 2. , The exterior part 3 corresponding to the upper part of the coil part 2
Even if the upper surface portion 11 and the lower surface portion 12 of the exterior portion 3 corresponding to the lower portion of the coil portion 2 are formed thin to achieve a low profile as a whole, the density of the upper surface portion 11 and the density of the lower surface portion 12 are intermediate. Since the density is higher than that of the portion 13, the upper surface portion 11
Further, it is possible to suppress the occurrence of magnetic saturation in the lower surface portion 12.

That is, the inside of the through hole 1 of the coil portion 2 corresponds to the intermediate portion 13 of the exterior portion 3.
3, the upper surface part 11 and the lower surface part 12 of the exterior part 3
Since the magnetic flux passing through the inside of the through hole 1 passes through the upper surface portion 11 and the lower surface portion 12 having a diameter smaller than the diameter of the through hole 1, the upper surface portion 11 and the lower surface portion 12 have an intermediate portion. The magnetic permeability can be increased as much as the density is higher than that of 13, and the height can be reduced without causing magnetic saturation in the upper surface portion 11 and the lower surface portion 12.

At this time, the intermediate portion 13 has an inner intermediate portion 15 corresponding to the through hole 1 of the coil portion 2 and an outer intermediate portion 14 corresponding to the outer portion of the outer peripheral surface of the coil portion 2, and has an outer intermediate portion. Since the density of the portion 14 is set to be higher than that of the inner intermediate portion 15, the outer intermediate portion 14 can increase the magnetic permeability by an amount corresponding to the larger density of the inner intermediate portion 15, and the outer intermediate portion 14 has a higher magnetic permeability. It is possible to reduce the size in the lateral direction without causing saturation and save space during mounting.

Particularly, in the exterior portion 3, the density of the upper surface portion 11 and the density of the lower surface portion 12 are set to 5.0 to 6.0 g / cm ³ ,
Since the density of the intermediate portion 13 is set to 85% to 95% of that density, stress to the coil portion 2 is not given more than necessary, and destruction of the coil portion 2 is suppressed, while the exterior caused by internal stress or the like. The destruction of the part 3 itself can be controlled. In addition, it is possible to suppress the occurrence of magnetic saturation and achieve size reduction.

The exterior part 3 is a dust core, and its material has a unique composition, which is advantageous for DC superposition characteristics (because the proportion of iron (Fe) component is large), and
The generation of rust due to the inclusion of iron (Fe) component can be suppressed (by the inclusion of chromium (Cr) component), and the loss in the high frequency region of 100 kHz or more can be suppressed (chromium (Cr) ≦ 8w.
Therefore, a composite magnetic material having excellent corrosion resistance can be realized without impairing magnetic properties.

In general, pressure molding is usually performed using a mold, but since the green compact 5 is a solid material, the mold 9 is used.
The amount of the green compact 5 between the coil portion 2 and the coil portion 2 does not easily fluctuate during re-press molding, and the coating thickness of the exterior portion 3 is likely to be uniform over the entire circumference of the coil portion 2. It is possible to suppress the characteristic variations such as the saturation characteristic and the magnetic loss when the values are superimposed on the direct current, and since the coil portion 2 can be supported by the green compact 5 itself, the positioning of the coil portion 2 becomes accurate and the defective molding of the exterior portion 3 is prevented. it can.
At this time, magnetic powder and a binder containing a thermosetting resin are mixed and pressed for the green compact 5, but a silicon resin having a high hardness resin component and an elastic resin component is used as the thermosetting resin. Therefore, it is possible to form the exterior part having a strength that balances hardness and brittleness, and reduce defects in the exterior part 3.

Furthermore, since the green compact 5 is re-pressure-molded to cover the coil portion 2, the coil portion 2 can be accurately covered, and there is no gap between the green compact 5 and the coil portion 2. It can also be filled to reduce the magnetic gap and improve the magnetic efficiency.

Particularly, since the hard portion of the green compact 5 firmly supports one surface of the coil portion 2, the coil portion 2 is re-pressed and molded.
Position deviation is less likely to occur, the weak hardness portion of the green compact 5 can easily cover the other surface of the coil portion 2 while destroying its shape, and the coating thickness of the exterior portion 3 can be the entire periphery of the coil portion 2. It is easy to make it uniform over the entire range, and it is possible to suppress characteristic variations.

The green compact 5 has an E shape having a middle leg portion 7 and an outer leg portion 8 on the rear face portion 6, the rear face portion 6 is a strong hardness portion, and the middle leg portion 7 and Since the outer leg portion 8 is a weak hardness portion, it is more difficult to cause a positional deviation with respect to the strong hardness portion of the green compact 5, and the other surface of the coil portion 2 can be easily covered, resulting in characteristic variations. Can be suppressed.

As described above, according to the embodiment of the present invention,
The coating thickness of the exterior portion 3 is likely to be uniform over the entire circumference of the coil portion 2 to suppress characteristic variations, and the upper surface portion 11 and the lower surface portion 12 of the exterior portion 3 have a higher density than the intermediate portion 13. The magnetic permeability can be increased by that amount, and the height can be reduced without causing magnetic saturation in the upper surface portion 11 and the lower surface portion 12.

In the embodiment of the present invention, the green compact 5 is used.
However, the length of the middle leg portion 7 may be longer or shorter than the length of the outer leg portion 8 or may have any other shape without departing from the spirit of the present invention. . In particular, a T-shape in which only the middle leg portion 7 is formed on the back surface portion 6 and a U-shape in which only the outer leg portion 8 is formed are considered to be substantially E-shaped.

Further, regarding the positional relationship between the coil portion 2 and the green compact 5, at least one of the green compacts 5 is not required even if the hard parts of the two green compacts 5 do not support one surface of the coil portion 2. It suffices that the strong hardness portion supports one surface of the coil portion 2.
At this time, the density of the strong hardness portion of the E-shaped green compact 5 may be made higher than the density of the weak hardness portion.

Further, the coil portion 2 may be an edgewise winding formed by winding a rectangular wire in addition to the round wire. In this case, the space factor can be improved and a large current can be accommodated. In particular, if the adjacent rectangular wires are closely contacted so that the exterior portion 3 is not formed between the adjacent rectangular wires, the exterior portion 3 is not formed between the rectangular wires, and the generation of magnetic flux circulating around the rectangular wires is suppressed. Therefore, the loss can be reduced.

As another example, as shown in FIGS. 7 and 8, one of the green compacts 5 has a backside portion 6 of a hard hardness portion and a coil portion 2 thereof.
One surface is supported, and the other green compact 5 is inserted into the through hole 1 of the coil part 2 by the middle leg portion 7 to be re-press-molded, or the middle legs of the two green compacts 5 are inserted. Part 7 and outer leg part 8
A fine concavo-convex portion 10 is provided at the tip of each of the two, and re-press molding is performed so that the middle leg portion 7 and the outer leg portion 8 of the two green compacts 5 face each other, and the back face portion 6 of the green compact 5 is formed. Alternatively, a dividing groove for dividing may be provided to perform re-pressure molding, and the other surface of the coil portion 2 can be more easily covered, and variation in characteristics can be suppressed.

At this time, in the embodiment of the present invention, the strong hardness portion of the green compact 5 supports one surface of the coil portion 2 before or during the re-pressure forming. Even after the pressure molding, it is desirable that the hard portion of the green compact support one surface of the coil portion 2.

[0073]

As described above, according to the present invention, the thickness of the coil portion (the distance between the coil portion and the surface of the exterior portion) that encloses the coil portion becomes smaller than the diameter of the through hole of the coil portion. Even if the upper surface of the exterior part corresponding to the upper part and the lower part of the exterior part corresponding to the lower part of the coil are thinly formed to achieve a low profile as a whole, the density of the upper part and the density of the lower part are reduced. Since the density is higher than that of the intermediate portion, it is possible to suppress the occurrence of magnetic saturation in the upper surface portion and the lower surface portion.

That is, the inside of the through hole of the coil portion corresponds to the intermediate portion of the exterior portion, but since the density of the upper surface portion and the lower surface portion of the exterior portion is higher than the density of this intermediate portion, the through hole Even if the magnetic flux passing through the inside passes through the upper surface portion and the lower surface portion that are smaller than the diameter of the through hole, the magnetic permeability can be increased in the upper surface portion and the lower surface portion because the density is larger than that in the intermediate portion. It is possible to provide a coil component having a low profile without causing magnetic saturation in the lower part and the lower part.

[Brief description of drawings]

FIG. 1 is a sectional view of a coil portion according to an embodiment of the present invention.

FIG. 2 is a perspective view of the same.

FIG. 3 is a diagram showing a part of the manufacturing process.

FIG. 4 is a perspective view of a green compact, which is the main part of the same.

FIG. 5 is a perspective view of a coil part to which terminals, which are the main parts, are connected.

FIG. 6 is a perspective view before forming a terminal, which is a main part of the same.

FIG. 7 is a diagram showing a part of another manufacturing step in the embodiment of the present invention.

FIG. 8 is a diagram showing a part of a manufacturing process of still another coil component in the embodiment of the present invention.

FIG. 9 is a perspective view of a conventional coil component.

FIG. 10 is a sectional view of the same.

FIG. 11 is a sectional view showing a part of the manufacturing process.

[Explanation of symbols]

1 through hole 2 coil part 3 Exterior 4 terminals 5 green compact 6 Rear part 7 Middle leg 8 outer legs 9 mold 10 Micro irregularities 11 Upper surface 12 Lower surface 13 Middle part 14 Outer middle part 15 Inner middle part

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tsuneji Imanishi             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Hidetoshi Hiwatari             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Tomokazu Kitagawa             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 5E043 AB04 FA04                 5E070 AA01 CA01

Claims (13)

[Claims] 1. A coil part having a through hole, an exterior part enclosing the coil part, and a terminal connected to the coil part and protruding from the exterior part, wherein the exterior part contains magnetic powder. And a lower surface portion corresponding to a lower portion of the coil portion, and an intermediate portion corresponding to a height portion of the coil portion. A coil component in which the inclusion thickness dimension that encloses the coil portion is smaller than the diameter of the through hole of the coil portion, and the density of the upper surface portion and the density of the lower surface portion are larger than the density of the intermediate portion. 2. The intermediate portion has an inner intermediate portion corresponding to the inside of the through hole of the coil portion and an outer intermediate portion corresponding to an outer portion of the outer peripheral surface of the coil portion, and the density of the outer intermediate portion is The coil component according to claim 1, wherein the density is higher than the density of the inner middle portion. 3. The exterior part has a top surface density and a bottom surface density of 5.0 to 6.0 g / cm ³ , and a middle part density of 85% to 98% of the top surface density and the bottom surface density. The coil component according to claim 1, which has a density of%. 4. The coil portion is an edgewise winding formed by winding a rectangular wire, and the adjacent rectangular wires are closely contacted so as not to form an exterior part between the adjacent rectangular wires. Coil parts. 5. The coil portion is formed by mixing a binder containing a thermosetting resin and a magnetic powder in an unheated state in which the thermosetting resin is not completely hardened and press-molding the outer casing. The coil component according to claim 1, wherein the coil component is re-pressure-molded so as to cover the resin and is heated and molded so that the thermosetting resin is completely cured. 6. The coil component according to claim 5, wherein the thermosetting resin is a silicon resin having a high hardness resin component and an elastic resin component. 7. The green compact is provided with a weak hardness portion having a hardness such that the shape of the green compact collapses during re-pressure molding,
The coil component according to claim 5, wherein two of the green compacts are molded, and the green compact is re-pressure-molded so that the weak hardness portion of the green compact covers the coil portion. 8. The green compact has a hardness of a hardness such that the shape of the green compact does not collapse during re-pressure molding and a hardness that the shape of the green compact collapses during the re-pressure molding. A weak hardness portion is provided, and the exterior portion has at least one of the pressed portion so that the strong hardness portion of the green compact supports one surface of the coil portion and the weak hardness portion covers the other surface of the coil portion. The coil component according to claim 7, wherein the powder is re-pressure-molded and heat-molded so that the thermosetting resin is thermoset. 9. The green compact has an E-shaped cross section having a middle leg portion and an outer leg portion on a back surface thereof, the back portion is a strong hardness portion, and the middle leg portion and the outer leg portion are formed. The coil component according to claim 8, wherein the leg portion is a weak hardness portion. 10. The coil component according to claim 9, wherein one of the green compacts and the other green compact are re-press-molded such that the back surface of the hard portion supports one surface of the coil portion. 11. One of the green compacts has a rear surface of the hardened portion supporting one surface of the coil portion, and the other green compact has an intermediate leg portion inserted into a through hole of the coil portion. hand,
The coil component according to claim 9, which is subjected to re-pressure molding. 12. A fine concavo-convex portion is provided at the tips of the middle leg and the outer leg of the two green compacts, and the middle leg and the outer leg of the two green compacts are opposed to each other. 10. The coil component according to claim 9, which is re-press molded. 13. The coil component according to claim 9, wherein a split groove for splitting is provided on the back surface of the green compact.