JP2950225B2 - Ferrite core and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ferrite core for a winding component such as a transformer or a choke coil mounted on an electronic device or an electric device, and a method for manufacturing the same.

[0002]

2. Description of the Related Art As winding parts such as a transformer and a choke coil used in electronic equipment and the like, those having the structure shown in FIGS. 9 to 11 have been proposed. In these figures, a winding component denoted by reference numeral 1 has a winding portion 2a in which a conductive wire W is wound in a coil shape, and is provided continuously on both sides of the winding portion 2a, and an end of the conductive wire W is connected. A bobbin 2 including terminal mounting portions 2b and 2c to which a plurality of terminals 3 are mounted, a rectangular parallelepiped inner core 4 disposed inside the winding portion 2a, and an outer periphery of the winding portion 2a And a frame-shaped external core 5 disposed so as to surround the outer core 5.

[0003] More specifically, the bobbin 2 is formed in a substantially rectangular shape by injection molding using a synthetic resin material having electrical insulation properties. Each of the terminal mounting portions 2b extends in a direction substantially orthogonal to
2c is formed, and the winding portion 2a is formed at a predetermined interval between the terminal mounting portions 2b and 2c at an intermediate portion in the length direction.

[0004] One terminal mounting portion 2 of the bobbin 2 is provided.
A mounting groove 2d in which the internal core 4 is mounted is formed in a range extending from the end face c to the vicinity of the other terminal mounting portion 2b through the winding portion 2a, and the mounting groove 2d is The portion other than the portion where the winding portion 2a is formed is opened upward (upward in FIG. 9).

[0005] The inner core 4 is a sintered body of ferrite powder, the thickness of which is slightly larger than the depth of the mounting groove 2d, the length of which is equal to the length of the mounting groove 2d, and the width of which is the same as that of the mounting groove 2d. The width of each of the mounting grooves 2d is substantially equal to the width of each of the mounting grooves 2d. It protrudes upward from the groove 2d.

Further, the outer core 5 is a sintered body of ferrite powder, and has a winding portion 2a of the bobbin 2 inside thereof.
Is formed to have a slightly larger through-hole 5a than the outer periphery of the winding portion 2a, and the cross-sectional shape of the peripheral wall is longer in the thickness direction of the bobbin 2 as shown in FIGS. A notch 5b into which a portion between the winding portion 2a and the terminal mounting portions 2b and 2c of the bobbin 2 is fitted is formed in a pair of parallel wall portions having a vertically elongated shape. Are formed so as to be opened downward.

As shown in FIG. 9, a plurality of conductors are wound around the winding portion 2a of the bobbin 2, and the ends of the plurality of conductors 3 are connected to respective terminals, as shown in FIG. 3
Then, the internal core 4 is inserted into the mounting groove 2d, and the external core 5 is attached so as to surround the winding portion 2a.

[0008] The winding member 1 assembled in this manner.
In the pair of cutouts 5b formed in the outer core 5, a magnetic path is formed by connecting the outer core 5 and the inner core 4 directly or indirectly via an insulating sheet. By adjusting the gap between the inner core 4 and the outer core 5, adjustment of electric characteristics,
That is, the adjustment of the inductance coefficient is performed.

[0009]

By the way, with the recent miniaturization of electronic devices and electric devices, it has been demanded to reduce the outer diameter of winding components mounted thereon.
In the winding component 1 having the above-described configuration, there is a limitation particularly in reducing the dimension in the width direction for the following reasons.

That is, the inner core 4 and the outer core 5 are formed by compacting ferrite powder and then sintering. In such a molding method,
In order to ensure the dimensional accuracy and strength of the obtained core, its minimum thickness T (see FIG. 11) is regulated.

Therefore, in the winding component 1 having the above-described configuration, the thickness of the peripheral wall of the outer core 5 is restricted, but the diameter and the winding amount of the conductive wire W in the winding portion 2a are limited. 1, the outer dimensions U of the winding part 2a are regulated, and the inner surface shape of the through hole 5a of the outer core 5 in which the winding part 2a is housed is determined by the winding part 2a. The minimum dimension V of the width of the outer core 5 as a whole is
It is almost unambiguously determined by the required performance of the winding component 1.

The through-hole 5a of the outer core 5 needs to be slightly larger than the outer dimensions of the winding portion 2a in order to accommodate the winding portion 2a. As shown in FIG. 11, the winding portion 2a and the through hole 5a
A gap g is formed between the inner wall and the inner wall, and the gap g has to be larger than a theoretically possible minimum width.

The present invention has been made in view of the above-mentioned problems, and it is a first object of the present invention to provide a ferrite core capable of minimizing the minimum width of a winding component.

Another object of the present invention is to provide a method for manufacturing a ferrite core capable of reliably obtaining a ferrite core for solving the first problem.

[0015]

According to a first aspect of the present invention, a ferrite core according to the present invention is inserted into a center portion of a wire wound in a coil shape, and both ends in the winding direction of the wound wire. A ferrite core comprising: an inner core protruding from a portion; and an outer core disposed along an outer periphery of the wound conductor, wherein the outer core is arranged in a winding direction of the wound conductor. A base portion that is positioned in contact with the wound conductor wire on one side along the edge of the inner core, and is protruded integrally at both ends of the base portion, and has side surfaces facing the side surfaces of both protruding portions of the inner core. A notch is formed at a position facing the internal core of each of these extended portions, and a notch into which the protrusion of the internal core is fitted is formed. Opposing surface of the extension and the inner core A gap is formed by interposing an insulating sheet on the base member, and a gap larger than the gap is formed between the extending portion and the inner core in the extending direction of the extending portion. And

[0016]

According to a second aspect of the present invention, there is provided a method for manufacturing a ferrite core.
An inner core that is inserted into the center of the coiled wire and protrudes from both ends of the wound wire in the winding direction, and is disposed along the outer periphery of the wound wire. A base which is located in contact with the wound conductor on one side along the winding direction of the wound conductor, and both ends of the base. A ferrite core comprising: a pair of extending portions which are integrally protruded from each other, and whose side surfaces are opposed to the side surfaces of both protruding portions of the inner core, wherein the ferrite core comprises a base portion of the outer core and a pair of extending portions. In addition to forming the connecting portion integrally, a thin connecting portion that connects between the end faces of these two extending portions is formed integrally, and the connecting portion is removed by grinding, and the connecting portion is ground. The inner cores of the two extending portions continuously By grinding a portion facing,
A cutout is formed in each of the extending portions so that the protruding portion of the inner core can be fitted therein.

According to a third aspect of the present invention, there is provided a method for manufacturing a ferrite core.
An inner core that is inserted into the center of the coiled wire and protrudes from both ends of the wound wire in the winding direction, and is disposed along the outer periphery of the wound wire. A base which is located in contact with the wound conductor on one side along the winding direction of the wound conductor, and both ends of the base. A ferrite core comprising: a pair of extended portions which are integrally protruded from each other and whose side surfaces are opposed to the side surfaces of both protruding portions of the inner core, wherein the outer core is formed in a rectangular shape. At the same time, a groove having a predetermined depth is formed in the middle part in the length direction of the pair of parallel sides, and the opposite side of the groove of the pair of sides is formed with a width larger than the width of the groove. And by grinding to a depth that reaches the groove 2 the pair of parallel sides in the longitudinal direction
It is characterized in that a pair of outer cores having a pair of extending portions are formed by dividing, and a notch is formed in each of the extending portions so that the protruding portion of the inner core is fitted.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG. In the following description, portions common to those in FIGS. 9 to 11 will be simplified by using the same reference numerals.

In FIG. 1, reference numeral 10 denotes a ferrite core according to the present embodiment.
Is a conductive wire wound in a coil shape (the winding portion 2 in FIG. 9).
a) inserted into the center portion of a), and protruded from both ends in the winding direction of the wound conductor (winding portion 2a); and the wound conductor (winding portion 2a) An outer core 12 is provided along the outer periphery of the base 12a, and the outer core 12 is located on a side of the wound conductor (winding portion 2a), and both ends of the base 12a. And a pair of extending portions 12b whose side surfaces are opposed to the side surfaces of both the projecting portions of the inner core 11, and the inner core 11 of each of these extending portions 12b At the position where the inner core 11 is opposed, a notch 13 into which the protrusion of the inner core 11 is fitted is formed.

To explain these details, the inner core 11 is formed in a thin rectangular parallelepiped shape. As shown in FIG. 2, the inner core 11 is inserted into a mounting groove 2d formed in the bobbin 2. And inserted into the bobbin 2 so as to be stored in a state where it is positioned on the bobbin 2 by being brought into contact with a terminal mounting portion 2 b formed at an end of the bobbin 2. In the state where it is stored in a predetermined position, both ends thereof are in the mounting groove 2d.
It is designed to be exposed from outside.

The outer core 12 is formed in a substantially U-shape and has a sectional area of FIGS.
The thickness X and the height Y of the base 12a are set so as to be the same as the cross-sectional area of the outer core 5 shown in FIG. A larger value is set to secure the magnetic path area.

Further, the extending portion 12b of the outer core 12
The notch 13 formed in the outer core 12 is formed at the time of compaction molding of the ferrite powder in the manufacturing process of the outer core 12, or as shown in FIG.
After baking in a state where the notch 13 is not formed, the portion H corresponding to the notch 13 is removed by grinding as shown by a dashed line in FIG. It is formed by doing.

Each notch 13 thus formed is formed such that the length along the thickness direction of the base 12a is larger than the width of the inner core 11.

In the ferrite core 10 according to the present embodiment thus configured, the inner core 11 is inserted into the mounting groove 2d of the bobbin 2 as shown in FIG. The external core 12 is inserted from the portion, the base portion 12a is brought into contact with the side portion of the winding portion 2a, and the extending portions 12b provided at both ends of the base portion 12a are connected to the winding portion 2b. By inserting both end portions of the internal core 11 into the notches 13 formed between the terminal mounting portions 2a and the terminal mounting portions 2b and 2c and formed in the extending portions 12b, As shown in FIG. 3, it is assembled as a winding component 14.

The outer core 12 and the inner core 11
As shown in FIG. 4, the insulating sheet 15 is interposed between the opposing surfaces with a predetermined gap a, and is mutually opposed by an adhesive applied to the insulating sheet 15. Integrated into

The outer core 12 is provided with the bobbin 2.
In the state where it is mounted on the inner surface of the base 12a,
The outer peripheral surface of the winding portion 2a is brought into contact with the outer surface of the winding portion 2a so that the gap between the winding portion 2a and the extending portion 12b of the notch 13 is substantially zero, as shown in FIG.
The gap b between the surface intersecting the extending direction of the inner core 11 and the side surface of the inner core 11 is sufficiently larger than the gap a between the opposing surfaces.

The winding component 1 assembled in this manner
4 is to increase the cross-sectional area of the base 12a of the outer core 12, thereby securing the cross-sectional area (that is, the magnetic path area) required of the outer core 12, preventing deterioration of the characteristics, When the cross-sectional area of the base portion 12a is increased, the dimension of the winding portion 2a, which has a relatively large margin, along the height direction can be increased, so that the thickness can be suppressed as small as possible. Can be kept small.

Further, the base 12a of the outer core 12 is disposed only on one side of the winding portion 2a, and the base 12a is brought into contact with the side surface of the winding portion 12a of the bobbin 2 so that a gap is formed. Since the width is set to zero, the width dimension can be kept small from this point as well.

Further, the gap b between the base 12a and the inner core 11 is larger than the gap a between the extending portion 12b of the outer core 12 and the inner core 11, so that the base 12a and the inner Most of the magnetic flux passing through the core 11 is converged on the opposing surface between the base 12a and the inner core 11, thereby suppressing generation of leakage magnetic flux. As a result, stable electric characteristics are obtained.

Therefore, the adjustment of the inductance coefficient of the winding component 14 is achieved by adjusting the thickness of the insulating sheet 15 interposed between the opposing surfaces of the base 12a and the inner core 11.
Adjustment of the gap a between the base 12a and the inner core 11 can be easily and reliably performed.

The various shapes and dimensions of each component shown in the above embodiment, the molding method, and the like are merely examples, and can be variously changed based on design requirements and the like.

For example, in the above embodiment, the outer core 11 is a substantially U-shaped molded body having a uniform height Y,
Although the example in which the notch 13 into which the inner core 11 is fitted is formed by grinding the distal end portion of each extending portion 12b has been described, instead of this, as shown in FIG. , A substantially U-shaped connecting portion 12c having a height equivalent to the depth of the notch 13 is continuously provided,
After this is fired, the notch 13 may be formed by grinding and removing the connecting portion 12c together with a part of each of the extending portions 12b, as shown by a dashed line in the figure.

When the outer core 12 is formed by such a method, the deformation of the outer core 12 during firing is suppressed by the connecting portion 12c, and dimensional accuracy is ensured.

As shown in FIG. 7, a groove 21 is formed along the width direction in the middle of each of a pair of parallel sides of a rectangular frame 20 having a uniform height. After firing the frame body 20, the opposite side of the pair of parallel sides opposite to the side on which the groove 21 is formed is, as shown by a dashed line in FIG. Also, by grinding and removing to a depth that reaches the groove 21 with a large width, the parallel pair of sides are separated from each other to form an extended portion 12b, and each of the separated sides has a predetermined shape. By forming the notch 13,
It is also possible to form two outer cores 12 at the same time.

Further, as shown in FIG. 8, instead of the groove 21 shown in FIG. 7, a frame 23 having a groove 22 having a V-shaped cross section is fired, and then the groove 22 is formed. 8, the side opposite to the side where the groove 22 is formed is ground and removed to a depth larger than the width of the groove 22 and near the groove 22 as shown by a dashed line in FIG. 8. Then, by applying an impact to the thin portion at the bottom of the groove 22, the thin portion is broken to separate each side to form the extended portion 12b. The cutout 13 having a predetermined shape may be formed so that the two outer cores 12 are formed at the same time.

And, by any of these methods,
While the above-mentioned outer core 12 is formed with high precision,
A number of outer cores 12 are obtained at the same time.

[0038]

As described above, according to the first aspect of the present invention,
According to the ferrite core according to the above, while being inserted into the center of the conductor wound in a coil shape, and an inner core projected from both ends of the winding direction of the wound conductor,
A ferrite core comprising an outer core disposed along the outer periphery of the wound conductive wire, wherein the outer core comprises:
A base that is positioned in contact with the wound conductor on one side along the winding direction of the wound conductor, and is integrally protruded at both ends of the base, and a side surface is formed inside the inner conductor. It consists of a pair of extending portions that are opposed to the side surfaces of both projecting portions of the core, and the projecting portions of the internal core are fitted to the positions of the extending portions that are opposed to the internal core. Notch is formed and said
An insulating sheet is interposed between the extension and the opposing surface of the inner core.
Gaps are formed by
A gap between the extending portion and the extending portion in the extending direction of the extending portion.
That is formed between the serial inner core characterized in, along with placing the base of the outer core only on one side of the winding portion, said base portion, conductive wires wound around the height direction By keeping the cross-sectional area required for the outer core small while keeping the cross-sectional area required for the outer core small, it can.

[0039] Therefore, such a ferrite core width of the coil component can be reduced with, also, since without the gaps in contact with the side surface of the conductive wire wound the base, this From the point of view, it is possible to reduce the above-described width dimension.

[0040]

According to the method of manufacturing a ferrite core according to the second aspect of the present invention, in particular, the base of the outer core and the two extending portions are integrally formed, and the end faces of the two extending portions are connected. After integrally forming the thin-walled connecting portion to be formed, the connecting portion is removed by grinding, and by grinding the facing portions of the two extended portions facing the internal core continuously to the grinding of the connecting portion, A cutout in which the inner core is fitted is formed in each of the extended portions, and the deformation of the outer core during firing is prevented by the connecting portion, and the dimensional accuracy of the outer core is reduced. Can be increased.

According to the method of manufacturing a ferrite core according to the third aspect of the present invention, the outer core is formed in a rectangular shape, and the outer core has a predetermined depth at an intermediate portion in a length direction of a pair of parallel sides. By forming a groove and grinding the opposite side of the pair of sides to the groove with a width larger than the width of the groove, and to a depth reaching the groove, the pair of parallel sides is formed. Is divided into two in the longitudinal direction to form a pair of outer cores having a pair of extending portions, and a notch in which the projecting portion of the inner core is fitted in each of the extending portions. By performing grinding on a pair of parallel sides, two external cores can be formed at the same time as the notch is formed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a ferrite core according to an embodiment of the present invention, showing a relative positional relationship in a mounted state.

FIG. 2 is an exploded perspective view showing a winding component to which the ferrite core according to the embodiment of the present invention is applied.

FIG. 3 is a plan view showing a winding component to which the ferrite core according to one embodiment of the present invention is applied.

FIG. 4 is an enlarged longitudinal sectional view showing a winding component to which the ferrite core according to one embodiment of the present invention is applied.

FIG. 5 is a perspective view for explaining a method of manufacturing an outer core constituting the ferrite core according to one embodiment of the present invention.

FIG. 6 is a perspective view for explaining another method of manufacturing the outer core constituting the ferrite core according to the embodiment of the present invention.

FIG. 7 is a perspective view for explaining another method for manufacturing the outer core constituting the ferrite core according to the embodiment of the present invention.

FIG. 8 is a side view for explaining another method for manufacturing the outer core constituting the ferrite core according to the embodiment of the present invention.

FIG. 9 is an exploded perspective view showing a winding component to which a conventional ferrite core is applied.

FIG. 10 is a plan view showing a winding component to which a conventional ferrite core is applied.

FIG. 11 is an enlarged longitudinal sectional view showing a winding component to which a conventional ferrite core is applied.

[Explanation of symbols]

 Reference Signs List 2 bobbin 2a winding part 2b / 2c terminal mounting part 10 ferrite core 11 inner core 12 outer core 12a base 12b extension 12c connecting part 13 notch 14 winding part 15 insulating sheet 20/23 frame 21/22 groove

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-281713 (JP, A) JP-A-4-245607 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01F 27/24-27/26

Claims (3)

(57) [Claims] An inner core (11) inserted into the center of a coiled wire (2a) and projected from both ends in the winding direction of the wound wire; A ferrite core (10) comprising an outer core (12) disposed along the outer periphery of the turned conductor,
A base portion (12a) in which the outer core is positioned in contact with the wound conductor on one side along a winding direction of the wound conductor, and integrally protrudes from both ends of the base; And a pair of extending portions (12b) whose side surfaces are opposed to the side surfaces of both protruding portions of the inner core, and the positions of the extending portions facing the inner core are: A notch (13) into which the protruding portion of the inner core is fitted is formed, and a gap (a) is formed by interposing an insulating sheet between the extending portion and the facing surface of the inner core. A ferrite core, wherein a gap (b) that is formed and is larger than the gap is formed between the extended portion and the inner core in the extending direction of the extended portion. 2. An inner core (11) inserted into the center of a coiled wire (2a) and projected from both ends in the winding direction of the wound wire; An outer core (12) disposed along the outer periphery of the wound conductor, the outer core being attached to the wound conductor on one side along the winding direction of the wound conductor. A base portion (12a) positioned in contact with the base portion, and a pair of extending portions (12b) projecting integrally from both ends of the base portion and having side surfaces opposed to side surfaces of both protruding portions of the inner core. A method of manufacturing a ferrite core (10) comprising: forming a base portion of the outer core and both extending portions integrally; and connecting a thin wall connecting portion between end faces of the both extending portions. 12c) is formed integrally,
The connecting portion is removed by grinding, and the portion of the both extending portions facing the inner core is ground continuously with the grinding of the connecting portion. A method for manufacturing a ferrite core, comprising forming a notch (13) into which a portion is fitted. 3. An inner core (11) inserted into the center of a coiled wire (2a) and projected from both ends in the winding direction of the wound wire; An outer core (12) disposed along the outer periphery of the wound conductor, the outer core being attached to the wound conductor on one side along the winding direction of the wound conductor. A base portion (12a) positioned in contact with the base portion, and a pair of extending portions (12b) projecting integrally from both ends of the base portion and having side surfaces opposed to side surfaces of both protruding portions of the inner core. A ferrite core (10) comprising: forming the outer core in a rectangular shape; and forming a groove (21) having a predetermined depth at an intermediate portion in a length direction of a pair of parallel sides thereof. Then, the opposite side of the pair of sides from the groove is The width is larger than the width of the groove, and
By grinding to the depth reaching the groove, the pair of parallel sides is divided into two in the length direction to form a pair of outer cores having a pair of extension portions, and each of the extension portions Forming a notch (13) into which the protrusion of the inner core is fitted.