U.S. patent number RE47,343 [Application Number 15/258,874] was granted by the patent office on 2019-04-09 for core for wire-wound electronic component, wire-wound electronic component, and common mode choke coil.
This patent grant is currently assigned to Murata Manufacturing Co., Ltd.. The grantee listed for this patent is MURATA MANUFACTURING CO., LTD.. Invention is credited to Takahiro Aoki, Masahiro Bando.
United States Patent |
RE47,343 |
Bando , et al. |
April 9, 2019 |
Core for wire-wound electronic component, wire-wound electronic
component, and common mode choke coil
Abstract
A core for a wire-wound electronic component. The core has a
winding base to be wound with a wire, and flanges located at both
ends of the winding base in an extending direction of the winding
base. The flanges protrude from the winding base in a first
direction perpendicular to the extending direction. Each of the
flanges has a plurality of protrusions on a first surface at a side
of the flange in the first direction. An inclined surface is
provided to extend from the first surface of each of the flanges to
a second surface of the winding base at a side of the winding base
in the first direction.
Inventors: |
Bando; Masahiro (Nagaokakyo,
JP), Aoki; Takahiro (Nagaokakyo, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
MURATA MANUFACTURING CO., LTD. |
Kyoto |
N/A |
JP |
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Assignee: |
Murata Manufacturing Co., Ltd.
(Kyoto-fu, JP)
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Family
ID: |
52448132 |
Appl.
No.: |
15/258,874 |
Filed: |
September 7, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
14331562 |
Jul 15, 2014 |
9159486 |
Oct 13, 2015 |
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Foreign Application Priority Data
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Aug 6, 2013 [JP] |
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2013-162868 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01F
27/292 (20130101); H01F 27/29 (20130101); B65H
75/06 (20130101); H01F 27/2828 (20130101); H01F
27/28 (20130101); H01F 27/292 (20130101); H01F
27/2828 (20130101); H01F 27/28 (20130101); H01F
17/04 (20130101); H01F 17/04 (20130101); H01F
27/29 (20130101); B65H 75/06 (20130101) |
Current International
Class: |
H01F
27/29 (20060101); H01F 27/28 (20060101); B65H
75/06 (20060101); H01F 17/04 (20060101) |
Field of
Search: |
;336/65,83,192,199,208,225 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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H11-204346 |
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Jul 1999 |
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JP |
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2000-208331 |
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Jul 2000 |
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JP |
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2006-147728 |
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Jun 2006 |
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JP |
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2008-294472 |
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Dec 2008 |
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JP |
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Other References
An Office Action; "Notification of Reasons for Rejection," issued
by the Japanese Patent Office on Jun. 23, 2015, which corresponds
to Japanese Patent Application No. 2013-162868 and is related to
the present U.S. Patent Application; with English language
translation. cited by applicant .
The First Office Action issued by the Chinese Patent Office on Jan.
28, 2016, which corresponds to Chinese Patent Application No.
201410379780.5 and is related to the present U.S. Patent
Application; with English language translation. cited by
applicant.
|
Primary Examiner: Whittington; Kenneth
Attorney, Agent or Firm: Studebaker & Brackett PC
Claims
What is claimed is:
.[.1. A core for a wire-wound electronic component, the core
comprising: a winding base to be wound with a wire; and flanges
located at both ends of the winding base in an extending direction
of the winding base and protruding from the winding base in a first
direction perpendicular to the extending direction, each of the
flanges having a plurality of protrusions on a first surface at a
side of the flange in the first direction, and an inclined surface
formed on the first surface of each of the flanges, in an area
extending from a space between the plurality of protrusions to a
second surface of the winding base at a side of the winding base in
the first direction, so as to be inclined to the second
surface..].
.[.2. The core according to claim 1, wherein the inclined surface
and the second surface are at an obtuse angle to each other when
viewed from a second direction perpendicular to the first direction
and the extending direction..].
.[.3. The core according to claim 2, wherein a third surface of
each of the flanges in contact with the winding base includes a
portion protruding from the winding base in the second direction;
and wherein the portion of the third surface protruding from the
winding base in the second direction is located farther in the
extending direction from a center of the winding base than a line
of intersection between the inclined surface and the second
surface..].
.[.4. The core according to claim 1 through 3, wherein the
plurality of protrusions are arranged in the second direction at
intervals..].
.[.5. A wire-wound electronic component comprising: a core
according to claim 1; a wire; and external electrodes provided on
the respective protrusions, wherein the wire extends on the
inclined surface..].
.[.6. A common mode choke coil comprising: a core according to
claim 1; a wire; and external electrodes provided on the respective
protrusions, wherein the wire extends on the inclined
surface..].
.Iadd.7. A core for a wire-wound electronic component, the core
comprising: a winding base to be wound with a wire; flanges located
at both ends of the winding base in an extending direction of the
winding base and protruding from the winding base in a first
direction perpendicular to the extending direction, at least one of
the flanges having a first protrusion and a second protrusion on a
first surface at a side of the flange in the first direction, the
first protrusion and the second protrusion being arranged with a
space therebetween in a second direction perpendicular to the first
direction and the extending direction; and an inclined surface
extending from the first surface to a part of a second surface of
the winding base, the second surface being located at a side of the
winding base in the first direction, wherein with respect to the
extending direction, the first surface lies between the inclined
surface and the first and the second protrusions, such that the
inclined surface does not contact the first and second protrusions,
and the inclined surface and the second surface are at an obtuse
angle to each other when viewed from the second direction
perpendicular to the first direction and the extending
direction..Iaddend.
.Iadd.8. The core according to claim 7, wherein when viewed from
the first direction, one of the first protrusion and the second
protrusion for each flange is substantially rectangular and has a
chamfered corner at an intersection between a side facing the
winding base and a side facing another of the first protrusion and
the second protrusion of the same flange..Iaddend.
.Iadd.9. The core according to claim 7, wherein a third surface of
each of the flanges in contact with the winding base includes a
portion protruding from the winding base in the second direction;
and wherein the portion of the third surface protruding from the
winding base in the second direction is located farther in the
extending direction from a center of the winding base than a line
of intersection between the inclined surface and the second
surface..Iaddend.
.Iadd.10. The core according to claim 7, wherein the first
protrusion and the second protrusion are arranged in the second
direction at intervals..Iaddend.
.Iadd.11. A common mode choke coil comprising: the core according
to claim 7; the wire; and external electrodes provided on the
respective protrusions, wherein the wire extends on the inclined
surface..Iaddend.
.Iadd.12. The common mode choke coil of claim 11, wherein for each
flange there is a non-chamfered protrusion and a chamfered
protrusion, and wherein the wire extends from an electrode of the
non-chamfered protrusion to a position between the chamfered corner
of the chamfered protrusion and the winding base before making
contact with the winding base..Iaddend.
.Iadd.13. A wire-wound electronic component comprising: a core for
the wire-wound electronic component, the core comprising: a winding
base to be wound with a wire; flanges located at both ends of the
winding base in an extending direction of the winding base and
protruding from the winding base in a first direction perpendicular
to the extending direction, at least one of the flanges having a
first protrusion and a second protrusion on a first surface at a
side of the flange in the first direction, the first protrusion and
the second protrusion being arranged with a space therebetween in a
second direction perpendicular to the first direction and the
extending direction; and an inclined surface extending from the
first surface to a part of a second surface of the winding base,
the second surface being located at a side of the winding base in
the first direction, wherein with respect to the extending
direction, the first surface lies between the inclined surface and
the first and the second protrusions, such that the inclined
surface does not contact the first and second protrusions, the
wire; and external electrodes provided on the respective
protrusions, wherein the wire extends on the inclined
surface..Iaddend.
.Iadd.14. The wire-wound electronic component of claim 13, wherein
for each flange there is a non-chamfered protrusion and a chamfered
protrusion, and wherein the wire extends from an electrode of the
non-chamfered protrusion to a position between the chamfered corner
of the chamfered protrusion and the winding base before making
contact with the winding base..Iaddend.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
.[.This application.]. .Iadd.The present application is a reissue
application under 35 U.S.C. .sctn. 251 of U.S. patent application
Ser. No. 14/331,562, filed Jul. 15, 2014, now U.S. Pat. No.
9,159,486, issued Oct. 13, 2015, which .Iaddend.claims benefit of
priority to Japanese Patent Application No. 2013-162868 filed Aug.
6, 2013, the entire content of which is incorporated herein by
reference.
TECHNICAL FIELD
The present disclosure relates to a core for a wire-wound
electronic component, a wire-wound electronic component, and a
common mode choke coil, and more particularly to the shape of a
flange of a core for a wire-wound electronic component.
BACKGROUND
As a conventional core for a wire-wound electronic component, a
core for a common mode choke coil disclosed by Japanese Patent
Laid-Open Publication No. H11-204346 is known. Such a core has
flanges at both ends of a winding base, and each of the flanges is
divided into two parts by a groove extending in a direction in
which the winding base extends. External electrodes are provided on
the respective parts of the flanges.
A wire wound around the core crosses the grooves while extending
from the winding base to the external electrodes. Therefore, the
parts of the wire crossing the grooves do not contact with the core
and float in the air. Therefore, when a common mode choke coil
using the core is mounted on a circuit board, if a foreign object
is stuck between either of the flanges and the circuit board, the
part of the wire crossing the groove will be pushed toward the
bottom of the groove, which may cause wire disconnection.
SUMMARY
An object of the present disclosure is to provide a core for a
wire-wound electronic component that can diminish the risk of wire
disconnection, a wire-wound electronic component, and a common mode
choke coil.
A first embodiment of the present disclosure relates to a core for
a wire-wound electronic component, and the core comprises: a
winding base to be wound with a wire; and flanges located at both
ends of the winding base in an extending direction of the winding
base and protruding from the winding base in a first direction
perpendicular to the extending direction. Each of the flanges has a
plurality of protrusions on a first surface at a side of the flange
in the first direction. An inclined surface is provided to extend
from the first surface of each of the flanges to a second surface
of the winding base at a side of the winding base in the first
direction.
A second embodiment of the present disclosure relates to a
wire-wound electronic component, and the wire-wound electronic
component comprises: the core described above; a wire; and external
electrodes provided on the respective protrusions.
A third embodiment of the present disclosure relates to a common
mode choke coil, and the common mode choke coil comprises: the core
described above; a wire; and external electrodes provided on the
respective protrusions.
The core for a wire-wound electronic component according to the
first embodiment comprises flanges located at both ends of a
winding base. Each of the flanges protrudes in a first direction
perpendicular to the central axis of the winding base and has a
plurality of protrusions on a first surface at the side of the
flange in the first direction. An inclined surface is provided to
extend from the first surface of each of the flanges to a second
surface of the winding base at the side of the winding base in the
first direction. Therefore, a wire wound around the core extends
from the winding base to each of the protrusions through the
inclined surface. The portion of the wire drawn on the inclined
surface does not float in the air. Therefore, when a wire-wound
electronic component using the core according to the first
embodiment is mounted on a circuit board, if a foreign object is
stuck between one of the flanges and the circuit board, it is less
likely that the wire is pushed and bent greatly by the foreign
object. Thus, the risk of wire disconnection can be diminished.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a wire-wound electronic component
according to an embodiment of the present disclosure.
FIG. 2 is a view showing a test conducted on the wire-wound
electronic component.
FIG. 3 is a perspective view of a wire-wound electronic component
according to a modification.
DETAILED DESCRIPTION
Structure of Wire-Wound Electronic Component
See FIG. 1
A wire-wound electronic component 1 according to an embodiment of
the present disclosure is described with reference to the drawings.
In the following paragraphs, a direction in which a winding base
extends is referred to as an x-direction. When viewed from the
x-direction, a direction parallel to longer sides of a flange 16 is
referred to as a y-direction, and a direction parallel to shorter
sides of the flange 16 is referred to as a z-direction. The
x-direction, y-direction and z-direction are perpendicular to one
another.
The wire-wound electronic component 1, as shown in FIG. 1,
comprises a core 12, wires 20 and 21, and external electrodes 22
through 25.
The core 12 is formed from a magnetic material, for example,
ferrite or the like, or an insulating material, for example,
alumina or the like. The core 12 comprises a winding base 14, and
flanges 16 and 18.
The winding base 14 is a prismatic member extending in the
x-direction. However, the winding base 14 does not need to be
prismatic, and may be cylindrical.
The flanges 16 and 18 are located at both ends of the winding base
14 in the x-direction (in the extending direction of the winding
base 14). Specifically, the flange 16 is located at a negative side
of the winding base 14 in the x-direction. The flange 18 is located
at a positive side of the winding base 14 in the x-direction.
The flange 16 protrudes from the winding base 14 at least in a
positive z-direction. In this embodiment, the flange 16 protrudes
from the winding base 14 in both the positive and negative
z-directions and in both the positive and negative y-directions.
Accordingly, the flange 16 protrudes from the winding base 14 in
all the directions perpendicular to the x-direction. An inclined
surface S12 is provided to extend from a surface S1 of the flange
16 at the positive side in the z-direction to a surface S10 of the
winding base 14 at the positive side in the z-direction. The
inclined surface S12 is a plane, and the inclined surface S12 and
the surface S10 are at an obtuse angle to each other when viewed
from the y-direction. Accordingly, a vector normal to the inclined
surface S12 has a component in the positive x-direction and a
component in the positive z-direction.
On the surface S1, protrusions 16a and 16b are arranged in this
order from the negative side to the positive side in the
y-direction. The protrusions 16a and 16b are spaced from each other
so as not to contact with each other. When viewed from the
z-direction, the protrusion 16a is substantially rectangular and
has a chamfered corner at an intersection between a side L1 at the
positive side in the x-direction and a side L2 at the positive side
in the y-direction. A surface S3 of the protrusion 16a at the
positive side in the z-direction is a plane. When viewed from the
z-direction, the protrusion 16b is rectangular, and a surface S4 of
the protrusion 16b at the positive side in the z-direction is a
plane.
The flange 18 protrudes from the winding base 14 at least in the
positive z-direction. In this embodiment, the flange 18 protrudes
from the winding base 14 in both the positive and negative
z-directions and in both the positive and negative y-directions.
Accordingly, the flange 18 protrudes from the winding base 14 in
all the directions perpendicular to the x-direction. An inclined
surface S14 is provided to extend from a surface S5 of the flange
18 at the positive side in the z-direction to a surface S10 of the
winding base 14 at the positive side in the z-direction. The
inclined surface S14 is a plane, and the inclined surface S14 and
the surface S10 are at an obtuse angle to each other when viewed
from the y-direction. Accordingly, a vector normal to the inclined
surface S14 has a component in the negative x-direction and a
component in the positive z-direction.
On the surface S5, protrusions 18a and 18b are arranged in this
order from the negative side to the positive side in the
y-direction. The protrusions 18a and 18b are spaced from each other
so as not to contact with each other. When viewed from the
z-direction, the protrusion 18a is rectangular, and a surface S7 of
the protrusion 18a at the positive side in the z-direction is a
plane. The protrusion 18b is substantially rectangular, and the
protrusion 18b has a chamfered corner at an intersection between a
side L3 at the negative side in the x-direction and a side L4 at
the negative side in the y-direction. A surface S8 of the
protrusion 18b at the positive side in the z-direction is a
plane.
The flanges 16 and 18 are symmetric with each other about a line
extending in the z-direction and passing through the center of the
winding base 14. When the wire-wound electronic component 1 is
mounted on a circuit board, the surfaces S3, S4, S7 and S8 of the
protrusions 16a, 16b, 18a and 18b serve as mounting surfaces to
face the circuit board.
The external electrodes 22 through 25 are formed of a Ni-based
alloy (for example, Ni--Cr, Ni--Cu, Ni or the like), Ag, Cu, Sn or
the like. The external electrode 22 is provided to extend across
the surface S3 of the protrusion 16a and the surroundings thereof.
The external electrode 23 is provided to extend across the surface
S4 of the protrusion 16b and the surroundings thereof. The external
electrode 24 is provided to extend across the surface S7 of the
protrusion 18a and the surroundings thereof. The external electrode
25 is provided to extend across the surface S8 of the protrusion
18b and the surroundings thereof.
The wires 20 and 21 are, as shown in FIG. 1, conductive wires wound
around the winding base 14. Each of the wires 20 and 21 has a core,
which is formed mainly of a conductive material such as copper,
silver or the like, coated with an insulating material such as
polyurethane or the like.
The negative end in the x-direction of the wire 20 is connected to
the external electrode 22 on the surface S3, and the positive end
in the x-direction of the wire 20 is connected to the external
electrode 24 on the surface S7. The negative end portion in the
x-direction of the wire 20 is drawn on the inclined surface S12 in
the negative x-direction and led to the surface S3 over the side
L1. The positive end portion in the x-direction of the wire 20 is
drawn on the inclined surface S14 in the positive x-direction and
in the negative y-direction and led to the surface S7 over a side
of the protrusion 18a at the positive side in the y-direction.
The negative end in the x-direction of the wire 21 is connected to
the external electrode 23 on the surface S4, and the positive end
in the x-direction of the wire 21 is connected to the external
electrode 25 on the surface S8. The negative end portion in the
x-direction of the wire 21 is drawn on the inclined surface S12 in
the negative x-direction and in the positive y-direction and led to
the surface S4 over a side of the protrusion 16b at the negative
side in the y-direction. The positive end portion in the
x-direction of the wire 21 is drawn on the inclined surface S14 in
the positive x-direction and led to the surface S8 over the side
L3.
Function of Wire-Wound Electronic Component
The wire-wound electronic component 1 having the structure above
functions as follows.
In the wire-wound electronic component 1, the wires 20 and 21 are
wound side by side on the same winding axis. Therefore, a magnetic
flux induced by an electric current flowing in the wire 20 passes
through the wire 21, and a magnetic flux induced by an electric
current flowing in the wire 21 passes through the wire 20.
At this time, when common-mode electric currents flow in the wires
20 and 21, the magnetic fluxes induced thereby are in the same
direction. Therefore, the magnetic fluxes induced on the wires 20
and 21 are reinforced by each other, and impedance to the common
mode electric currents occurs.
On the other hand, when normal-mode electric currents flow in the
wires 20 and 21, the magnetic fluxes induced thereby are the
opposite direction to each other. Therefore, no impedance to the
normal-mode electric currents occurs. Thus, the wire-wound
electronic component 1 functions as a common mode choke coil.
Method for Manufacturing Wire-Wound Electronic Component
Next, a method for manufacturing the wire-wound electronic
component according to the embodiment is described.
First, as a material for the core 12, powder of a ferrite-based
material is prepared. The prepared ferrite powder is filled in a
female die, and the powder filled in the female die is pressed with
a male die. Thereby, the powder is molded into the core 12 having
the winding base 14, and the flanges 16 and 18.
After the molding of the core 12 having the winding base 14, and
the flanges 16 and 18, the core 12 is sintered, whereby the core 12
is completed.
Next, the external electrodes 22 through 25 are formed on the
protrusions 16a, 16b, 18a and 18b of the flanges 16 and 18 of the
core 12. More specifically, in a container filled with Ag paste,
the protrusions 16a, 16b, 18a and 18b are dipped so that the Ag
paste can stick to the protrusions 16a, 16b, 18a and 18b. Next, the
Ag paste stuck on the protrusions 16a, 16b, 18a and 18b is dried
and baked, whereby Ag films are formed on the protrusions 16a, 16b,
18a and 18b as base electrodes. Further, a metal film, for example,
formed from a Ni-based alloy is formed on each of the Ag films by
electroplating or the like. In this way, the external electrodes 22
through 25 are formed.
Next, the wires 20 and 21 are wound around the winding base 14. In
this moment, both ends of a predetermined length of each of the
wires 20 and 21 are led out from the winding base 14. The led-out
portions of the wires 20 and 21 are connected to the external
electrodes 22 through 25 by thermocompression bonding. Through the
processes above, the electronic component 1 is completed.
Advantageous Effects
See FIGS. 1 and 2
In the wire-wound electronic component 1, the end portion of the
wire 21 in the negative x-direction, when viewed from the positive
side in the z-direction, extends in the positive y-direction across
the space between the protrusions 16a and 16b. The end of the wire
21 in the negative x-direction is connected to the external
electrode 23 on the surface S4. In this regard, since the core 12
of the wire-wound electronic component 1 has the inclined surface
S12, the end portion of the wire 21 in the negative x-direction
extends on the inclined surface S12 to the surface S4. Accordingly,
the portion of the wire 21 extending on the inclined surface S12
does not float in the air. When the wire-wound electronic component
1 is mounted on a circuit board, therefore, if a foreign object is
stuck between the flange 16 and the circuit board, it is less
likely that the end portion of the wire 21 in the negative
x-direction is pushed and bent greatly by the foreign object. Thus,
the risk of wire disconnection can be diminished. With regard to
the end portion of the wire 20 in the positive x-direction, the
provision of the inclined surface S14 diminishes the risk of wire
disconnection for the same reason.
In order to prove the advantageous effect above, the inventors
simulated a situation where a foreign object is stuck between one
of the flanges of the wire-wound electronic component and a circuit
board. Specifically, samples of the wire-wound electronic component
1 were used as samples of Type 1, and wire-wound electronic
components each using a core having the structure disclosed by
Japanese Patent Laid-Open Publication No. H11-204346 were used as
samples of Type 2. A simulated test was conducted on each of the
samples. Specifically, as shown by FIG. 2, the flange 16 was loaded
with 10 (N) for one minute with the wound wire located between the
flange 16 and the weight W. In each of the samples of Type 1 and
Type 2, the wires have diameters of 30 .mu.m. The simulated test
was conducted on fifty samples of Type 1 and fifty samples of Type
2.
As a result, no samples of Type 1 had wire disconnection, while 44
samples of Type 2 had wire disconnection. This result proves that
the wire-wound electronic component 1 has an advantageous effect of
diminishing the risk of wire disconnection.
Further, the external electrodes 22 and 23 are provided
respectively on the protrusions 16a and 16b provided on the surface
S1 of the flange 16, and the external electrodes 24 and 25 are
provided respectively on the protrusions 18a and 18b provided on
the surface S5 of the flange 18. Thus, the external electrodes 22
through 25 are separated from one another. Therefore, the electric
current flowing in the wire 20 and the electric current flowing in
the wire 21 are prevented from crossing, and the risk of crosstalk
can be diminished.
Modification
See FIG. 3
A wire-wound electronic component 1A is, as shown in FIG. 3,
different from the wire-wound electronic component 1 in the shapes
of the flanges 16 and 18.
Specifically, in the wire-wound electronic component 1A, with
regard to a surface S2 of the flange 16 in contact with the winding
base 14, as shown in FIG. 3, portions S2a and S2b protruding from
the winding base 14 in the y-direction are located at a more
negative side in the x-direction than a line of intersection L5
between the inclined surface S12 and the surface S10. In other
words, the portions S2a and S2b of the surface S2 are located
farther in the x-direction from a center point CP of the winding
base 14 than the line of intersection L5.
Also, with regard to a surface S6 of the flange 18 in contact with
the winding base 14, portions protruding from the winding base 14
in the positive and negative y-directions are located farther in
the x-direction from the center point CP of the winding base 14
than a line of intersection between the inclined surface S14 and
the surface S10. There is no other difference in structure between
the wire-wound electronic component 1A and the wire-wound
electronic component 1. Accordingly, the descriptions of the
elements of the wire-wound electronic component 1 other than the
descriptions of the flanges 16 and 18 apply to the wire-wound
electronic component 1A.
In the electronic component 1A according to the modification, the
portions S2a and S2b of the surface S2 protruding from the winding
base 14 in the positive and negative y-directions are located at a
more negative side in the x-direction than the line of intersection
L5. Therefore, the winding base 14 of the electronic component 1A
has a larger surface area than that of the electronic component 1.
Thus, in the wire-wound electronic component 1A, the area to be
wound with the wires 20 and 21 is increased, and the adjustment of
inductance value is easy compared with the wire-wound electronic
component 1.
Other Embodiments
Cores for wire-wound electronic components, wire-wound electronic
components and common mode choke coils according to the present
disclosure are not limited to the embodiment and modification
above.
In the embodiment and modification above, the inclined surfaces S12
and S14 are planes. However, the inclined surfaces S12 and S14 may
be curved surfaces. Specifically, the inclined surfaces S12 and S14
may be convex surfaces protruding in the positive z-direction or
may be concave surfaces receding in the negative z-direction.
Although the present disclosure has been described in connection
with the preferred embodiments above, it is to be noted that
various changes and modifications may be obvious to persons skilled
in the art. Such changes and modifications are to be understood as
being within the scope of the disclosure.
* * * * *