U.S. patent application number 15/173700 was filed with the patent office on 2016-12-15 for magnetic device including winding and insulators, and power conversion device using the same.
The applicant listed for this patent is Panasonic Intellectual Property Management Co., Ltd.. Invention is credited to MOTOHIKO FUJIMURA, AKIRA KATO, YOSHITAKE NAKAGAWA, KAZUYUKI SAKIYAMA, TAKEHIKO YAMAKAWA.
Application Number | 20160365804 15/173700 |
Document ID | / |
Family ID | 57517374 |
Filed Date | 2016-12-15 |
United States Patent
Application |
20160365804 |
Kind Code |
A1 |
NAKAGAWA; YOSHITAKE ; et
al. |
December 15, 2016 |
MAGNETIC DEVICE INCLUDING WINDING AND INSULATORS, AND POWER
CONVERSION DEVICE USING THE SAME
Abstract
A magnetic device includes a winding, and insulators by which
the winding is surrounded. Each of the insulators is in contact
with the winding. A gap exists between each two adjacent of the
insulators in a winding direction of the winding.
Inventors: |
NAKAGAWA; YOSHITAKE; (Osaka,
JP) ; YAMAKAWA; TAKEHIKO; (Osaka, JP) ;
FUJIMURA; MOTOHIKO; (Osaka, JP) ; KATO; AKIRA;
(Osaka, JP) ; SAKIYAMA; KAZUYUKI; (Osaka,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Panasonic Intellectual Property Management Co., Ltd. |
Osaka |
|
JP |
|
|
Family ID: |
57517374 |
Appl. No.: |
15/173700 |
Filed: |
June 5, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01F 2005/025 20130101;
H01F 27/325 20130101; H02M 3/337 20130101; H01F 5/02 20130101; Y02B
70/10 20130101; H01F 5/06 20130101; Y02B 70/1491 20130101; H02M
2001/0058 20130101 |
International
Class: |
H02M 3/335 20060101
H02M003/335; H01F 5/06 20060101 H01F005/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 12, 2015 |
JP |
2015-119386 |
Claims
1. A magnetic device comprising: a winding; and insulators by which
the winding is surrounded, each of the insulators being in contact
with the winding, a gap existing between each two adjacent of the
insulators in a winding direction of the winding.
2. The magnetic device according to claim 1, wherein the insulators
include a first insulator and a second insulator.
3. The magnetic device according to claim 2, wherein the insulators
further include a third insulator.
4. The magnetic device according to claim 1, wherein the winding
includes a pair of linear portions that extend in a linear
direction when viewed from a winding axis direction of the winding,
a length of each of the pair of linear portions is longer than 1/4
of a length of one turn of the winding, and two of the insulators
are in contact with the winding along the linear direction.
5. The magnetic device according to claim 2, wherein the winding
includes a first portion that extends in a first direction when
viewed from a winding axis direction of the winding, and a second
portion that extends in a second direction and is shorter than the
first portion, and the gap between one end of the first insulator
and one end of the second insulator is located beside the second
portion.
6. The magnetic device according to claim 2, wherein the winding
has a corner when viewed from a winding axis direction of the
winding, and the gap between one end of the first insulator and one
end of the second insulator is located beside the corner.
7. The magnetic device according to claim 2, wherein one end of the
first insulator and one end of the second insulator oppose each
other through the gap, and the one end of the first insulator and
the one end of the second insulator each have a stepped end
face.
8. The magnetic device according to claim 2, wherein one end of the
first insulator and one end of the second insulator oppose each
other through the gap, the one end of the first insulator has a
recess, and the one end of the second insulator has a protrusion
that engages with the recess of the first insulator.
9. The magnetic device according to claim 1, further comprising:
another winding outside of the winding, the insulators being
bobbins around which the other winding is wound.
10. The magnetic device according to claim 1, wherein the gap is
larger than 0 mm and equal to or less than 3 mm.
11. A power conversion device comprising: the magnetic device
according to claim 1; and a power conversion circuit that is
connected to the winding.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The present disclosure relates to a magnetic device and a
power conversion device using the same.
[0003] 2. Description of the Related Art
[0004] In recent years, power electronics has been attracting
attention for the purpose of overcoming environmental problems and
energy problems. Power conversion circuits often require
high-voltage large-current operations. Consequently, securing the
insulating property of transformers used in power conversion
circuits and heat-dissipation measures for windings and cores are
required.
[0005] Japanese Patent No. 3481541 discloses a conventional
transformer in which a primary winding and a secondary winding are
wound concentrically, and the windings are molded with a
thermosetting insulating resin having high thermal
conductivity.
SUMMARY
[0006] A magnetic device according to an aspect of the present
disclosure includes a winding, and insulators by which the winding
is surrounded, each of the insulators being in contact with the
winding, a gap existing between each two adjacent of the insulators
in a winding direction of the winding.
[0007] Additional benefits and advantages of the disclosed
embodiments will become apparent from the specification and
drawings. The benefits and/or advantages may be individually
obtained by the various embodiments and features of the
specification and drawings, which need not all be provided in order
to obtain one or more of such benefits and/or advantages.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a perspective view depicting an example of the
structure of a transformer according to embodiment 1;
[0009] FIG. 2 is a cross-sectional view along a plane that includes
the winding axis of the transformer according to embodiment 1;
[0010] FIG. 3 is an exploded perspective view of the transformer
according to embodiment 1;
[0011] FIG. 4 is a cross-sectional view along a plane perpendicular
to the winding axis direction of the transformer according to
embodiment 1;
[0012] FIG. 5 is a drawing depicting an example of heat
distribution in a cross section along a plane that includes the
winding axis of a transformer according to a comparative
example;
[0013] FIG. 6 is a drawing depicting an example of heat
distribution in a cross section along a plane that includes the
winding axis of the transformer according to embodiment 1;
[0014] FIG. 7 is a cross-sectional view along an XY plane depicting
an example of the shape of an end of an outer bobbin;
[0015] FIG. 8 is a cross-sectional view along the XY plane
depicting an example of the shape of the end of the outer
bobbin;
[0016] FIG. 9 is a cross-sectional view along the XY plane
depicting an example of the shape of the end of the outer
bobbin;
[0017] FIG. 10 is a cross-sectional view along the XY plane
depicting an example of the shape of the end of the outer
bobbin;
[0018] FIG. 11 is a cross-sectional view along a plane
perpendicular to the winding axis direction of the structure of a
transformer according to a modified example of embodiment 1;
[0019] FIG. 12 is a perspective view schematically depicting a
modified example of the structure of a core according to embodiment
1;
[0020] FIG. 13 is an exploded perspective view of a transformer
according to embodiment 2;
[0021] FIG. 14 is a cross-sectional view along a plane
perpendicular to the winding axis direction of the transformer
according to embodiment 2;
[0022] FIG. 15 is a cross-sectional view along an XY plane
depicting an example of the shape of an end of an outer bobbin;
[0023] FIG. 16 is an exploded perspective view of a transformer
according to embodiment 3;
[0024] FIG. 17 is a cross-sectional view along a plane
perpendicular to the winding axis direction of the transformer
according to embodiment 3;
[0025] FIG. 18 is an exploded perspective view of a transformer
according to embodiment 4;
[0026] FIG. 19 is a cross-sectional view along a plane
perpendicular to the winding axis direction of the transformer
according to embodiment 4;
[0027] FIG. 20 is an exploded perspective view of a transformer
according to embodiment 5;
[0028] FIG. 21 is a cross-sectional view along a plane
perpendicular to the winding axis direction of the transformer
according to embodiment 5;
[0029] FIG. 22 is a drawing depicting a modified example of the
structure of a core according to embodiment 5;
[0030] FIG. 23 is a drawing depicting a modified example of the
structure of the core according to embodiment 5;
[0031] FIG. 24 is a cross-sectional view along a plane
perpendicular to the winding axis direction of a coil device
according to embodiment 5;
[0032] FIG. 25 is a circuit diagram depicting an example of a
phase-shift full-bridge circuit;
[0033] FIG. 26 is a circuit diagram depicting an example of an LLC
resonant half-bridge circuit;
[0034] FIG. 27 is a cross-sectional view depicting the structure of
a transformer of a comparative example; and
[0035] FIG. 28 is a cross-sectional view depicting the structure of
a transformer of another comparative example.
DETAILED DESCRIPTION
Underlying Knowledge Forming Basis of the Present Disclosure
[0036] First, the findings forming the basis of the present
disclosure will be described.
[0037] FIG. 27 depicts a transformer of a comparative example. In
FIG. 27, winding 908a and winding 908b are primary windings, and
winding 909a and winding 909b are secondary windings. In the
transformer of FIG. 27, in order to improve the heat dissipating
property of these windings, these windings are molded with a
sealing resin 903 having high thermal conductivity.
[0038] FIG. 28 depicts a transformer of another comparative
example. In FIG. 28, an outer winding 912 is wound onto the outside
of an inner winding 911. Then, after these windings have been
wound, the windings are molded with a thermosetting insulating
resin having high thermal conductivity. In this transformer, the
inner winding 911 functions as a primary winding, and the outer
winding 912 functions as a secondary winding. In FIG. 28, in order
to handle winding-thickening that occurs when the inner winding 911
is wound onto an inner bobbin 914, an air layer is provided between
an outer bobbin 913 and the inner winding 911.
[0039] The transformer depicted in FIG. 27 has a problem in that
the sealing resin 903 for increasing the heat dissipating property
of the primary windings and the secondary windings causes the
weight of the transformer to increase.
[0040] The transformer depicted in FIG. 28 has a problem in that,
in the case where winding pressure is applied to the outer bobbin
913 due to the outer winding 912 being wound around, the outer
bobbin 913 bends toward the air layer. If this bending becomes
excessive, there is a risk of the outer bobbin 913 breaking.
[0041] The transformer depicted in FIG. 28 has a problem in that
variation in the winding-thickening or winding-thinning of the
inner winding 911 causes the distance between the inner winding 911
and the outer winding 912 to vary, and leakage inductance therefore
varies.
[0042] Thus, the present inventors examined a magnetic device in
which a bobbin and a winding are brought into close contact. This
magnetic device enables heat of the winding to be dissipated via
the bobbin. For example, the sealing resin can be reduced or
omitted to reduce weight of the device while maintaining a high
heat dissipating property.
[0043] In consideration of the above, the present inventors arrived
at the present disclosure.
Overview of Embodiments
[0044] A magnetic device according to one aspect of the present
disclosure is provided with a winding in which a conductive wire is
wound around, and a bobbin arranged at the outer peripheral side of
the winding. The bobbin includes a first bobbin member and a second
bobbin member, and an end of the first bobbin member opposes an end
of the second bobbin member. The winding and the first bobbin
member are provided in contact with each other, and the winding and
the second bobbin member are provided in contact with each other. A
gap is provided between the end of the first bobbin member and the
end of the second bobbin member in the circumferential winding
direction of the winding.
[0045] According to the present aspect, the winding and the first
and second bobbin members can be appropriately brought into contact
even in the case where the winding has become thicker and even in
the case where the winding has become thinner. Consequently, heat
can be suitably dissipated via the first bobbin member and the
second bobbin member even when the winding generates heat. In the
case where resin molding is omitted or reduced, the weight of the
magnetic device can be reduced while securing the heat dissipating
property of the winding. Furthermore, the distance between an inner
winding and an outer winding is fixed to correspond to the bobbin
thickness, and therefore leakage inductance is stable even in the
case where the winding has become thicker and even in the case
where the winding has become thinner.
[0046] In the aforementioned aspect, the bobbin may further include
a third bobbin member. The other end of the first bobbin member may
oppose one end of the third bobbin member. The other end of the
second bobbin member may oppose the other end of the third bobbin
member. The winding and the third bobbin member may be provided in
contact with each other. A gap may be provided between an end of
the first bobbin member and an end of the third bobbin member in
the circumferential winding direction of the winding. A gap may be
provided between an end of the second bobbin member and an end of
the third bobbin member in the circumferential winding direction of
the winding.
[0047] It should be noted that the "first bobbin member" is an
example of a "first insulator", the "second bobbin member" is an
example of a "second insulator", and the "third bobbin member" is
an example of a "third insulator".
[0048] In this case, the winding and the first, second, and third
bobbin members can be appropriately brought into contact even in
the case where the winding has become thicker and even in the case
where the winding has become thinner, and heat of the winding can
be dissipated via these bobbin members.
[0049] In the aforementioned aspect, the winding may be formed with
the conductive wire being wound around in a shape including a short
area and a long area. The end of the first bobbin member and the
end of the second bobbin member may be located beside the short
area of the winding.
[0050] In this case, the long area of the winding and the first and
second bobbin members can be appropriately brought into contact.
Thus, a comparatively large contact area can be secured, and heat
of the winding can be suitably dissipated via the first bobbin
member and the second bobbin member.
[0051] In the aforementioned aspect, the winding may be formed with
the conductive wire being wound around in a shape including a short
area and a long area. The end of the first bobbin member and the
end of the second bobbin member may oppose a portion between the
short area of the winding and the long area of the winding.
[0052] In this case, the long area of the winding and the first
bobbin member can be appropriately brought into contact, and the
short area of the winding and the second bobbin member can be
appropriately brought into contact. Alternatively, the short area
of the winding and the first bobbin member can be appropriately
brought into contact, and the long area of the winding and the
second bobbin member can be appropriately brought into contact. As
a result, heat of the winding can be suitably dissipated via the
first bobbin member and the second bobbin member even in the case
where there are variations in the winding action for the
winding.
[0053] It should be noted that the "long area of the winding" is an
example of a "first portion of the winding", and the "short area of
the winding" is an example of a "second portion of the winding".
Furthermore, the "long area of the winding" is an example of a
"linear portion of the winding". The length of the long area and/or
linear portion of the winding is longer than 1/4 of the length of
one turn of the winding, for example.
[0054] In the aforementioned aspect, the end of the first bobbin
member and the end of the second bobbin member may have a stepped
face.
[0055] In this case, the creepage distance from the inner
circumferential side to the outer circumferential side in the ends
of the first and second bobbin members can become longer. The
insulating property can be therefore improved.
[0056] In the aforementioned aspect, one of the end of the first
bobbin member and the end of the second bobbin member may have a
return structure that engages with the other.
[0057] In this case, the first bobbin member and the second bobbin
member can be less likely to detach. As a result, it is possible to
prevent loosening in the case where a winding is wound around a
bobbin.
[0058] A power conversion device according to one aspect of the
present disclosure is provided with the magnetic device of any of
the aforementioned aspects, and a power conversion circuit that is
connected to the winding.
[0059] According to the present aspect, heat generated in the
winding by the operation of the power conversion circuit can be
suitably dissipated via the first bobbin member and the second
bobbin member.
[0060] Hereinafter, embodiments according to the present disclosure
will be described with reference to the drawings. It should be
noted that the same reference symbols are used for the same
constituent elements in the drawings.
[0061] It should be noted that the embodiments described
hereinafter all represent comprehensive or specific examples. The
numerical values, the shapes, the materials, the constituent
elements, the arrangement positions and modes of connection of the
constituent elements, and the like given in the following
embodiments are examples and are not intended to restrict the
present disclosure. Furthermore, constituent elements that are not
described in the independent claims indicating the most significant
concepts from among the constituent elements in the following
embodiments are described as optional constituent elements.
Embodiment 1
[0062] FIG. 1 is a perspective view schematically depicting the
structure of a transformer 101 according to embodiment 1. FIG. 2 is
a cross-sectional view along a YZ plane including the winding axis
of the transformer 101 depicted in FIG. 1. FIG. 3 is an exploded
perspective view depicting the transformer 101 depicted in FIG. 1.
FIG. 4 is a cross-sectional view along an XY plane perpendicular to
the winding axis direction of the transformer 101 depicted in FIG.
1. The transformer 101 is an example of a "magnetic device" in the
present disclosure.
[0063] The transformer 101 is used in a power conversion circuit
such as a DC-DC converter. The structure of the transformer 101
will be described using FIGS. 1 to 4.
[0064] The transformer 101 is provided with an inner bobbin 102, an
inner winding 106, an outer bobbin 103, an outer winding 104, and a
core 107.
[0065] The inner bobbin 102 is formed of an insulating resin, for
example. The inner bobbin 102 includes an inner column 102A
extending in the winding axis direction (i.e., Z direction), an
inner upper flange 102B formed at one end of the inner column 102A,
and an inner lower flange 102C formed at the other end. The inner
column 102A may have a square column shape.
[0066] The inner winding 106 is formed of a conductive wire such as
a single wire or a litz wire. The inner winding 106 is wound onto
the inner bobbin 102. As depicted in FIG. 4, the inner winding 106
is formed with the conductive wire being wound around, in a shape
having a short area SA parallel to the Y direction and a long area
LA parallel to the X direction.
[0067] The outer bobbin 103 is formed of an insulating resin, for
example. The outer bobbin 103 includes a first bobbin member 103X
and a second bobbin member 103Y. The first bobbin member 103X and
the second bobbin member 103Y have the same shape, and are formed
in a squared U-shape when viewed from the Z direction. The ends of
the first bobbin member 103X oppose the ends of the second bobbin
member 103Y. Gaps 105 are provided between the ends of the first
bobbin member 103X and the ends of the second bobbin member 103Y in
the winding direction of the inner winding 106. The size of the
gaps 105 may be larger than 0 mm and equal to or less than 3 mm,
for example.
[0068] The first bobbin member 103X and the second bobbin member
103Y each include an outer column 103A extending in the winding
axis direction (i.e., Z direction), an outer upper flange 103B
formed at one end of the outer column 103A, and an outer lower
flange 103C formed at the other end. The outer columns 103A and
103B constitutes a square column by being assembled. The shape of
the ends of the first bobbin member 103X and the ends of the second
bobbin member 103Y are described later on.
[0069] The outer winding 104 is formed of a conductive wire such as
a single wire or a litz wire. The outer winding 104 is wound onto
the outer bobbin 103.
[0070] The core 107 is formed of a magnetic material such as a
ferrite, a dust core, or an amorphous alloy. The core 107 includes
a core 107A and a core 107B. The core 107A and the core 107B have
the same shape, and are formed in an E-shape when viewed from the X
direction. Hereinafter, the core 107A and the core 107B are
sometimes collectively referred to as the core 107.
[0071] The gaps 105 in the outer bobbin 103 are located beside the
short areas of the inner winding 106, as depicted in FIG. 4. The
outer bobbin 103 and the long areas of the inner winding 106 are
thereby in contact with each other.
[0072] When the transformer 101 is assembled, first, the inner
winding 106 is wound onto the inner column 102A of the inner bobbin
102. Next, the outer bobbin 103 is arranged by being made to slide
along the XY plane such that the outer column 103A comes into
contact with the inner winding 106. Next, the outer winding 104 is
wound onto the outer column 103A. Finally, the core 107 is arranged
by being made to slide along the ZY plane.
[0073] The gaps 105 in the outer bobbin 103 become larger as the
inner winding 106 becomes thicker, and the gaps 105 becomes smaller
as the inner winding 106 becomes thinner. Therefore, in either
case, the pair of long areas of the inner winding 106 and the outer
bobbin 103 are appropriately in contact. As a result, heat of the
inner winding 106 can be suitably transmitted to the outer bobbin
103, and thus the heat dissipating property of the inner winding
106 can be improved.
[0074] Next, an example will be described in which the results of a
thermal analysis of windings in a coil device according to the
present embodiment and a coil device according to a comparative
example are compared.
[0075] FIG. 5 depicts a temperature distribution along a YZ plane
that includes the winding axis in the coil device having the
structure of the comparative example. FIG. 6 depicts a temperature
distribution along a YZ plane that includes the winding axis in the
coil device according to the present embodiment.
[0076] In the thermal analysis depicted in FIG. 6, a coil device
having the structure depicted in FIG. 4 was used as the coil device
according to the present embodiment. This coil device has gaps
beside short areas of a winding. Long areas of a winding 112 and a
bobbin 111 are therefore in contact.
[0077] Meanwhile, a coil device having a structure such as that
depicted in FIG. 28 was used as the coil device according to the
comparative example. In the coil device used in the thermal
analysis of FIG. 5, gaps are not provided in joining parts 915 of
the outer bobbin 913, and an air layer 114 is provided between the
winding 112 and the bobbin 111.
[0078] In FIGS. 5 and 6, a thermal analysis was carried out without
there being a core or an outer winding. In both of the coil
devices, a loss of 10 W was given for the inner winding. The
ambient temperature was 25.degree. C. A heat sink 113 was arranged
so as to be in contact with the bottom face of the coil devices,
and the temperature of the heat sink 113 was 15.degree. C.
[0079] In FIG. 5, the highest value of the temperature of the
winding 112 reaches 47.5.degree. C., whereas, in FIG. 6, the
highest value of the temperature of the winding 112 is suppressed
to 37.5.degree. C. From these results, it is apparent that, in the
structure of the present embodiment, a rise in the temperature of
the winding can be suppressed compared to the structure of the
comparative example.
[0080] FIGS. 7 and 8 are cross-sectional views along an XY plane
depicting examples of the shape of an end 103Xt of the first bobbin
member 103X and an end 103Yt of the second bobbin member 103Y.
[0081] In FIG. 7, the end 103Xt of the first bobbin member 103X
includes a base end 103Xa and a protrusion 103Xb that protrudes
from the base end 103Xa. The end 103Yt of the second bobbin member
103Y includes a base end 103Ya and a protrusion 103Yb that
protrudes from the base end 103Ya. The end 103Xt of the first
bobbin member 103X and the end 103Yt of the second bobbin member
103Y oppose each other.
[0082] Specifically, the protrusion 103Xb of the first bobbin
member 103X and the base end 103Ya of the second bobbin member 103Y
oppose each other through the gap 105, and the protrusion 103Yb of
the second bobbin member 103Y and the base end 103Xa of the first
bobbin member 103X oppose each other through the gap 105.
Furthermore, the protrusion 103Xb of the first bobbin member 103X
and the protrusion 103Yb of the second bobbin member 103Y abut in
the X direction.
[0083] To paraphrase, the end 103Xt of the first bobbin member 103X
has a stepped end face that includes an end face of the base end
103Xa and an end face and a side face of the protrusion 103Xb. The
end 103Yt of the second bobbin member 103Y has a stepped end face
that includes an end face of the base end 103Ya and an end face and
a side face of the protrusion 103Yb. These two stepped end faces
oppose each other.
[0084] In FIG. 8, the end 103Xt of the first bobbin member 103X
includes an inclined end face 103Xc between the base end 103Xa and
the protrusion 103Xb. The end 103Yt of the second bobbin member
103Y includes an inclined end face 103Yc between the base end 103Ya
and the protrusion 103Yb.
[0085] In FIG. 8, the protrusion 103Xb of the first bobbin member
103X and the base end 103Ya of the second bobbin member 103Y oppose
each other through the gap 105, and the protrusion 103Yb of the
second bobbin member 103Y and the base end 103Xa of the first
bobbin member 103X oppose each other through the gap 105.
Furthermore, the inclined end face 103Xc of the first bobbin member
103X and the inclined end face 103Yc of the second bobbin member
103Y oppose each other through the gap 105.
[0086] To paraphrase, the end 103Xt of the first bobbin member 103X
has a stepped end face that includes the end face of the base end
103Xa, the end face of the protrusion 103Xb, and the inclined end
face 103Xc. The end 103Yt of the second bobbin member 103Y has a
stepped end face that includes the end face of the base end 103Ya,
the end face of the protrusion 103Yb, and the inclined end face
103Yc. These two stepped end faces oppose each other.
[0087] Due to the end 103Xt of the first bobbin member 103X and the
end 103Yt of the second bobbin member 103Y each having a stepped
end face as depicted in FIGS. 7 and 8, the creepage distance of the
outer bobbin 103 between the inner winding 106 and the outer
winding 104 can be lengthened without losing the heat dissipating
property of the inner winding 106. As a result, the insulating
property can be improved.
[0088] FIGS. 9 and 10 are cross-sectional views along the XY plane
depicting other examples of the shape of the end 103Xt of the first
bobbin member 103X and the end 103Yt of the second bobbin member
103Y.
[0089] In FIG. 9, the protrusion 103Xb of the first bobbin member
103X includes, at a tip thereof, an engaging part 103Xd that
extends in the X direction. The protrusion 103Yb of the second
bobbin member 103Y includes, at a tip thereof, a semicircular
engaging part 103Yd that is formed protruding in the X
direction.
[0090] In FIG. 9, the protrusion 103Xb of the first bobbin member
103X and the base end 103Ya of the second bobbin member 103Y oppose
each other through the gap 105, and the protrusion 103Yb of the
second bobbin member 103Y and the base end 103Xa of the first
bobbin member 103X oppose each other through the gap 105.
[0091] In FIG. 9, as the gaps 105 widens, the engaging part 103Xd
of the first bobbin member 103X and the engaging part 103Yd of the
second bobbin member 103Y engage.
[0092] To paraphrase, the end 103Xt of the first bobbin member 103X
has a recess defined by the base end 103Xa, the protrusion 103Xb,
and the engaging part 103Xd. The end 103Yt of the second bobbin
member 103Y has a protrusion serving as the engaging part 103Yd.
The protrusion of the end 103Yt of the second bobbin member 103Y
engages with the recess in the end 103Xt of the first bobbin member
103X.
[0093] The structure depicted in FIG. 10 is different from the
structure depicted in FIG. 9 only in that the engaging part 103Yd
of the second bobbin member 103Y is formed in a triangular
shape.
[0094] Due to the engaging part 103Xd being provided in the end
103Xt of the first bobbin member 103X and the engaging part 103Yd
being provided in the end 103Yt of the second bobbin member 103Y as
depicted in FIGS. 9 and 10, the second bobbin member 103Y can be
less likely to detach from first bobbin member 103X when the outer
winding 104 is wound. Furthermore, the creepage distance of the
outer bobbin 103 between the inner winding 106 and the outer
winding 104 can be lengthened without losing the heat dissipating
property of the inner winding 106. As a result, the insulating
property can be improved.
[0095] FIG. 11 is a cross-sectional view along an XY plane
perpendicular to the winding axis direction of a transformer 101A
according to a modified example of the present embodiment. In FIG.
11, the inner winding 106 is formed with a conductive wire being
wound around, in a shape having arc-shaped areas that have a chord
extending in the Y direction, and long areas extending in the X
direction. It should be noted that the arc-shaped areas of the
inner winding 106 are an example of a "corner". Furthermore, the
first bobbin member 103X and the second bobbin member 103Y have the
same shape, and are formed in a U-shape when viewed from the Z
direction. The outer bobbin 103 and the inner winding 106 are in
close contact at linear portions, and therefore the same effect as
that of the transformer 101 can be obtained also in a case such as
this.
[0096] As described above, in embodiment 1, a pair of linear
portions (e.g., a pair of long areas) of the outer bobbin 103 and
the inner winding 106 are in close contact. Therefore, bending is
less likely to occur in the outer bobbin 103 and the possibility of
the outer bobbin 103 breaking can be reduced even in the case where
winding pressure is applied to the outer bobbin 103 when the outer
winding 104 is wound around the outer bobbin 103.
[0097] The gaps 105 in the outer bobbin 103 become smaller in the
case where the inner winding 106 becomes thinner due to variation
that occurs when winding is performed. The gaps 105 in the outer
bobbin 103 become larger in the case where the inner winding 106
becomes thicker due to variation that occurs when winding is
performed. In either case, the distance between the inner winding
106 and the outer winding 104 is fixed to correspond to the
thickness of the outer bobbin 103. It is therefore possible to
reduce variation in leakage inductance. Furthermore, a bobbin
having a structure same as or similar to the outer bobbin 103 may
be additionally arranged outside of the outer winding 104. It is
thereby possible to also improve the heat dissipating property of
the outer winding 104.
[0098] The transformer 101 may not have the core 107.
[0099] The core 107 depicted in FIG. 3 is made up of the two
E-shaped cores 107A and 107B, but there is no restriction thereto.
For example, the core 107 may be made up of an E-shaped core and an
I-shaped core.
[0100] FIG. 12 is a perspective view schematically depicting
another example configuration of the core. As depicted in FIG. 12,
the central leg of the core is divided, and a structure is possible
in which one pair of cores 109 having a squared U-shape when viewed
from the X direction are fit together in the Z direction, and two
pairs of such cores 109 are made to abut in the Y direction.
[0101] In the example depicted in FIG. 4, the winding axis of the
inner winding 106 and the winding axis of the outer winding 104 are
shared, but there is no restriction thereto, and a central axis
that is different from the inner winding 106 and the outer winding
104 may be shared.
Embodiment 2
[0102] A designer can design various bobbins on the basis of the
design principles described in relation to embodiment 1. In
embodiment 2, a magnetic device provided with two bobbin members
arranged with gaps therebetween is described.
[0103] FIG. 13 is an exploded perspective view of a transformer
101B according to embodiment 2. FIG. 14 is a cross-sectional view
along an XY plane perpendicular to the winding axis direction of
the transformer 101B. It should be noted that a cross-sectional
view along a YZ plane that includes the winding axis of the
transformer 101B is the same as FIG. 2. The transformer 101B is an
example of a "magnetic device" in the present disclosure. The
structure of the transformer 101B of embodiment 2 will be described
using FIGS. 2, 13, and 14.
[0104] The transformer 101B is provided with an inner bobbin 102,
an inner winding 106, an outer bobbin 103, an outer winding 104,
and a core 107.
[0105] The inner bobbin 102 is formed of an insulating resin, for
example. The inner bobbin 102 includes an inner column 102A
extending in the winding axis direction (i.e., Z direction), an
inner upper flange 102B formed at one end of the inner column 102A,
and an inner lower flange 102C formed at the other end.
[0106] The inner winding 106 is formed of a conductive wire such as
a single wire or a litz wire. The inner winding 106 is wound onto
the inner bobbin 102. As depicted in FIG. 14, the inner winding 106
is formed with the conductive wire being wound around, in a shape
having short areas parallel to the Y direction and long areas
parallel to the X direction.
[0107] The outer bobbin 103 is formed of an insulating resin, for
example. The outer bobbin 103 includes a first bobbin member 103P,
a second bobbin member 103Q, and a third bobbin member 103R. The
first bobbin member 103P and the second bobbin member 103Q are
formed in an L-shape when viewed from the Z direction. The third
bobbin member 103R is formed in an I-shape when viewed from the Z
direction.
[0108] One end of the first bobbin member 103P opposes one end of
the second bobbin member 103Q. The other end of the first bobbin
member 103P opposes one end of the third bobbin member 103R. The
other end of the second bobbin member 103Q opposes the other end of
the third bobbin member 103R. Gaps 105 are provided between the
ends of the bobbin members in the winding direction of the inner
winding 106.
[0109] The first bobbin member 103P, the second bobbin member 103Q,
and the third bobbin member 103R each include an outer column 103A
extending in the winding axis direction (i.e., Z direction), an
outer upper flange 103B formed at one end of the outer column 103A,
and an outer lower flange 103C formed at the other end. The outer
columns 103A of the first to third bobbin members 103P, 103Q, and
103R constitutes a square column by being assembled.
[0110] The outer winding 104 is formed of a conductive wire such as
a single wire or a litz wire. The outer winding 104 is wound onto
the outer bobbin 103.
[0111] The core 107 is formed of a magnetic material such as a
ferrite, a dust core, or an amorphous alloy. The core 107 includes
a core 107A and a core 107B. The core 107A and the core 107B each
have the same shape, and are formed in an E-shape when viewed from
the X direction. Hereinafter, the core 107A and the core 107B are
sometimes collectively referred to as the core 107.
[0112] As depicted in FIG. 14, the gap 105 between the first bobbin
member 103P and the second bobbin member 103Q is located beside a
first short area of the inner winding 106. As depicted in FIG. 14,
the gap 105 between the first bobbin member 103P and the third
bobbin member 103R is located beside a corner between a second
short area and a first long area of the inner winding 106, and the
gap 105 between the second bobbin member 103Q and the third bobbin
member 103R is located beside a corner between the second short
area and a second long area of the inner winding 106. The outer
bobbin 103 and the inner winding 106 are thereby in contact with
each other at the long areas of the inner winding 106 and the
second short area in FIG. 14.
[0113] When the transformer 101B is assembled, first, the inner
winding 106 is wound onto the inner column 102A of the inner bobbin
102. Next, the outer bobbin 103 is arranged by being made to slide
along the XY plane such that the outer column 103A comes into
contact with the inner winding 106. Next, the outer winding 104 is
wound onto the outer column 103A. Finally, the core 107 is arranged
by being made to slide along the ZY plane.
[0114] The gaps 105 in the outer bobbin 103 become larger as the
inner winding 106 becomes thicker, and the gaps 105 becomes smaller
as the inner winding 106 becomes thinner. In either case, the pair
of long areas and one short area of the inner winding 106 and the
outer bobbin 103 are appropriately in contact. As a result, heat of
the inner winding 106 can be suitably transmitted to the outer
bobbin 103, and thereby the heat dissipating property of the inner
winding 106 can be improved.
[0115] FIG. 15 is a cross-sectional view along the XY plane
depicting an example of the shape of an end 103Pt of the first
bobbin member 103P and an end 103Rt of the third bobbin member
103R.
[0116] In FIG. 15, the end 103Pt of the first bobbin member 103P
includes a base end 103Pa and a protrusion 103Pb that protrudes
from the base end 103Pa. The end 103Rt of the third bobbin member
103R includes a base end 103Ra and a protrusion 103Rb that
protrudes from the base end 103Ra. The end 103Pt of the first
bobbin member 103P and the end 103Rt of the third bobbin member
103R oppose each other.
[0117] Specifically, the protrusion 103Pb of the first bobbin
member 103P and the base end 103Ra of the third bobbin member 103R
oppose each other through the gap 105, and the protrusion 103Rb of
the third bobbin member 103R and the base end 103Pa of the first
bobbin member 103P oppose each other through the gap 105.
Furthermore, the protrusion 103Pb of the first bobbin member 103P
and the protrusion 103Rb of the third bobbin member 103R are
adjacent in the Y direction.
[0118] To paraphrase, the end 103Pt of the first bobbin member 103P
has a stepped end face that includes an end face of the base end
103Pa and an end face and a side face of the protrusion 103Pb. The
end 103Rt of the third bobbin member 103R has a stepped end face
that includes an end face of the base end 103Ra and an end face and
a side face of the protrusion 103Rb. These two stepped end faces
oppose each other.
[0119] Due to the end 103Pt of the first bobbin member 103P and the
end 103Rt of the third bobbin member 103R each having a stepped end
face as depicted in FIG. 15, the creepage distance of the outer
bobbin 103 between the inner winding 106 and the outer winding 104
can be lengthened without losing the heat dissipating property of
the inner winding 106. As a result, the insulating property can be
improved.
[0120] It should be noted that, in embodiment 2, the shape
described with reference to FIGS. 7 to 10 may be adopted for the
shape of the end 103Pt of the first bobbin member 103P and an end
103Qt of the second bobbin member 103Q. The same effect can be
obtained by means of these shapes. Furthermore, a shape such as
that depicted in FIG. 11 may be adopted also for the shape of the
transformer 101B of embodiment 2. The same effect can be obtained
also with this shape.
[0121] As described above, in embodiment 2, the outer bobbin 103 is
made up of the three bobbin members 103P, 103Q, and 103R. Compared
to the example given in embodiment 1, the contact area can be
thereby increased by an amount corresponding to the short area of
the inner winding 106 coming into contact with the outer bobbin
103. Therefore, according to embodiment 2, the heat dissipating
property can be further improved compared to embodiment 1.
[0122] The outer bobbin 103 and linear portions (e.g., long areas)
of the inner winding 106 are in close contact. With this
configuration, bending is less likely to occur in the outer bobbin
103 even in the case where winding pressure is applied to the outer
bobbin 103 when the outer winding 104 is wound around the outer
bobbin 103. Therefore, the possibility of the outer bobbin 103
breaking can be reduced.
[0123] The distance between the inner winding 106 and the outer
winding 104 is fixed to correspond to the thickness of the outer
bobbin 103. It is therefore possible to reduce variation in leakage
inductance. Furthermore, a bobbin having a structure same as or
similar to the outer bobbin 103 may be additionally arranged
outside of the outer winding 104. It is thereby possible to also
improve the heat dissipating property of the outer winding 104.
[0124] The transformer 101B may not have the core 107.
[0125] The core 107 depicted in FIG. 13 is made up of the two
E-shaped cores 107A and 107B, but there is no restriction thereto.
The core 107 may be made up of four squared U-shaped cores, for
example. Alternatively, the core 107 may be made up of an E-shaped
core and an I-shaped core.
[0126] In the example depicted in FIG. 14, the winding axis of the
inner winding 106 and the winding axis of the outer winding 104 are
shared, but there is no restriction thereto, and a central axis
that is different from the inner winding 106 and the outer winding
104 may be shared.
Embodiment 3
[0127] A designer can design various bobbins on the basis of the
design principles described in relation to embodiment 1. In
embodiment 3, a magnetic device provided with four bobbin members
arranged with gaps therebetween is described.
[0128] FIG. 16 is an exploded perspective view of a transformer
101C according to embodiment 3. FIG. 17 is a cross-sectional view
along an XY plane perpendicular to the winding axis direction of
the transformer 101C. It should be noted that a cross-sectional
view along a YZ plane that includes the winding axis of the
transformer 101C is the same as FIG. 2. The structure of the
transformer 101C of embodiment 3 will be described using FIGS. 2,
16, and 17.
[0129] The transformer 101C is provided with an inner bobbin 102,
an inner winding 106, an outer bobbin 103, an outer winding 104,
and a core 107.
[0130] The inner bobbin 102 is formed of an insulating resin, for
example. The inner bobbin 102 includes an inner column 102A
extending in the winding axis direction (i.e., Z direction), an
inner upper flange 102B formed at one end of the inner column 102A,
and an inner lower flange 102C formed at the other end.
[0131] The inner winding 106 is formed of a conductive wire such as
a single wire or a litz wire. The inner winding 106 is wound onto
the inner bobbin 102. As depicted in FIG. 17, the inner winding 106
is formed with the conductive wire being wound around, in a shape
having short areas parallel to the Y direction and long areas
parallel to the X direction.
[0132] The outer bobbin 103 is formed of an insulating resin, for
example. The outer bobbin 103 includes a first bobbin member 103I,
a second bobbin member 103J, a third bobbin member 103K, and a
fourth bobbin member 103L. The first to fourth bobbin members 103I,
103J, 103K, and 103L are formed in L-shapes when viewed from the Z
direction.
[0133] One end of the first bobbin member 103I opposes one end of
the second bobbin member 103J. The other end of the first bobbin
member 103I opposes one end of the third bobbin member 103K. The
other end of the second bobbin member 103J opposes one end of the
fourth bobbin member 103L. The other end of the third bobbin member
103K opposes the other end of the fourth bobbin member 103L. Gaps
105 are provided between the ends of the bobbin members in the
winding direction of the inner winding 106.
[0134] The first to fourth bobbin members 103I, 103J, 103K, and
103L each include an outer column 103A extending in the winding
axis direction (i.e., Z direction), an outer upper flange 103B
formed at one end of the outer column 103A, and an outer lower
flange 103C formed at the other end. The outer columns 103A of the
first to fourth bobbin members 103I, 103J, 103K, and 103L
constitutes a square column by being assembled.
[0135] The outer winding 104 is formed of a conductive wire such as
a single wire or a litz wire. The outer winding 104 is wound onto
the outer bobbin 103.
[0136] The core 107 is formed of a magnetic material such as a
ferrite, a dust core, or an amorphous alloy. The core 107 includes
a core 107A and a core 107B. The core 107A and the core 107B each
have the same shape, and are formed in an E-shape when viewed from
the X direction. Hereinafter, the core 107A and the core 107B are
sometimes collectively referred to as the core 107.
[0137] As depicted in FIG. 17, the gap 105 between the first bobbin
member 103I and the second bobbin member 103J is located beside a
first long area of the inner winding 106; the gap 105 between the
third bobbin member 103K and the fourth bobbin member 103L is
located beside a second long area of the inner winding 106; the gap
105 between the first bobbin member 103I and the third bobbin
member 103K is located beside a first short area of the inner
winding 106; and the gap 105 between the second bobbin member 103J
and the fourth bobbin member 103L is located beside a second short
area of the inner winding 106.
[0138] When the transformer 101C is assembled, first, the inner
winding 106 is wound onto the inner column 102A of the inner bobbin
102. Next, the outer bobbin 103 is arranged by being made to slide
along the XY plane such that the outer column 103A comes into
contact with the inner winding 106. Next, the outer winding 104 is
wound onto the outer column 103A. Finally, the core 107 is arranged
by being made to slide along the ZY plane.
[0139] The gaps 105 in the outer bobbin 103 become larger as the
inner winding 106 becomes thicker, and the gaps 105 becomes smaller
as the inner winding 106 becomes thinner. In either case, L-shaped
areas, each including a corner, of the inner winding 106 and the
outer bobbin 103 are appropriately in contact. As a result, heat of
the inner winding 106 can be suitably transmitted to the outer
bobbin 103, and thereby the heat dissipating property of the inner
winding 106 can be improved.
[0140] It should be noted that, in embodiment 3, the shape
described with reference to FIGS. 7 to 10 may be adopted for the
shape of the ends of the first to fourth bobbin members 103I, 103J,
103K, and 103L. The same effect can be obtained by means of these
shapes. Furthermore, a shape such as that depicted in FIG. 11 may
be adopted also for the shape of the transformer 101C in embodiment
3. The same effect can be obtained also with this shape.
[0141] As described above, in embodiment 3, the outer bobbin 103 is
made up of the four bobbin members 103I, 103J, 103K, and 103L. The
contact area between the inner winding 106 and the outer bobbin 103
thereby increases compared to embodiment 1. Therefore, according to
embodiment 3, the heat dissipating property can be further improved
compared to embodiment 1. Furthermore, the outer bobbin 103 of
embodiment 2 is made up of two types of bobbin members; however,
the outer bobbin 103 of embodiment 3 may be made up of one type of
bobbin member, for example. The types of components can thereby be
lessened.
[0142] The outer bobbin 103 and L-shaped areas, each including a
corner, of the inner winding 106 are in close contact. With this
configuration, bending is less likely to occur in the outer bobbin
103 even in the case where winding pressure is applied to the outer
bobbin 103 when the outer winding 104 is wound around the outer
bobbin 103. Therefore, the possibility of the outer bobbin 103
breaking can be reduced.
[0143] The distance between the inner winding 106 and the outer
winding 104 is fixed to correspond to the thickness of the outer
bobbin 103. It is therefore possible to reduce variation in leakage
inductance. Furthermore, a bobbin having a structure same as or
similar to the outer bobbin 103 may be additionally arranged
outside of the outer winding 104. It is thereby possible to also
improve the heat dissipating property of the outer winding 104.
[0144] The transformer 101C may not have the core 107.
[0145] The core 107 depicted in FIG. 16 is made up of the two
E-shaped cores 107A and 107B, but there is no restriction thereto.
The core 107 may be made up of four squared U-shaped cores, for
example. Alternatively, the core 107 may be made up of an E-shaped
core and an I-shaped core.
[0146] In the example depicted in FIG. 17, the winding axis of the
inner winding 106 and the winding axis of the outer winding 104 are
shared, but there is no restriction thereto, and a central axis
that is different from the inner winding 106 and the outer winding
104 may be shared.
Embodiment 4
[0147] A designer can design various bobbins on the basis of the
design principles described in relation to embodiment 1. In
embodiment 4, a magnetic device provided with two L-shaped bobbin
members arranged with gaps therebetween is described.
[0148] FIG. 18 is an exploded perspective view of a transformer
101D according to embodiment 4. FIG. 19 is a cross-sectional view
along an XY plane perpendicular to the winding axis direction of
the transformer 101D. It should be noted that a cross-sectional
view along a YZ plane that includes the winding axis of the
transformer 101D is the same as FIG. 2. The structure of the
transformer 101D of embodiment 4 will be described using FIGS. 2,
18, and 19.
[0149] The transformer 101D is provided with an inner bobbin 102,
an inner winding 106, an outer bobbin 103, an outer winding 104,
and a core 107.
[0150] The inner bobbin 102 is formed of an insulating resin, for
example. The inner bobbin 102 includes an inner column 102A
extending in the winding axis direction (i.e., Z direction), an
inner upper flange 102B formed at one end of the inner column 102A,
and an inner lower flange 102C formed at the other end.
[0151] The inner winding 106 is formed of a conductive wire such as
a single wire or a litz wire. The inner winding 106 is wound onto
the inner bobbin 102. As depicted in FIG. 19, the inner winding 106
is formed with the conductive wire being wound around, in a shape
having short areas parallel to the Y direction and long areas
parallel to the X direction.
[0152] The outer bobbin 103 is formed of an insulating resin, for
example. The outer bobbin 103 includes a first bobbin member 103M
and a second bobbin member 103N. The first and second bobbin
members 103M and 103N have the same shape and are formed in an
L-shape when viewed from the Z direction.
[0153] One end of the first bobbin member 103M opposes one end of
the second bobbin member 103N. The other end of the first bobbin
member 103M opposes the other end of the second bobbin member 103N.
Gaps 105 are provided between the ends of the bobbin members in the
winding direction of the inner winding 106.
[0154] The first and second bobbin members 103M and 103N each
include an outer column 103A extending in the winding axis
direction (i.e., Z direction), an outer upper flange 103B formed at
one end of the outer column 103A, and an outer lower flange 103C
formed at the other end. The outer columns 103A and 103B
constitutes a square column by being assembled.
[0155] The outer winding 104 is formed of a conductive wire such as
a single wire or a litz wire. The outer winding 104 is wound onto
the outer bobbin 103.
[0156] The core 107 is formed of a magnetic material such as a
ferrite, a dust core, or an amorphous alloy. The core 107 includes
a core 107A and a core 107B. The core 107A and the core 107B each
have the same shape, and are formed in an E-shape when viewed from
the X direction. Hereinafter, the core 107A and the core 107B are
sometimes collectively referred to as the core 107.
[0157] As depicted in FIG. 19, a first gap 105 is located beside a
first corner (e.g., top-left corner) of the inner winding 106, and
a second gap 105 is located beside a second corner (e.g., the
bottom-right corner) of the inner winding 106. The first and second
corners each are located between a long area and a short area of
the inner winding 106.
[0158] When the transformer 101D is assembled, first, the inner
winding 106 is wound onto the inner column 102A of the inner bobbin
102. Next, the outer bobbin 103 is arranged by being made to slide
along the XY plane such that the outer column 103A comes into
contact with the inner winding 106. Next, the outer winding 104 is
wound onto the outer column 103A. Finally, the core 107 is arranged
by being made to slide along the ZY plane.
[0159] The gaps 105 in the outer bobbin 103 become larger as the
inner winding 106 becomes thicker, and the gaps 105 becomes smaller
as the inner winding 106 becomes thinner. In either case, the outer
bobbin 103 and an L-shaped area from the upper long area of the
inner winding 106 to the right-side short area are appropriately in
contact, and the outer bobbin 103 and an L-shaped area from the
left-side short area of the inner winding 106 to the lower long
area are appropriately in contact in FIG. 19. As a result, heat of
the inner winding 106 can be suitably transmitted to the outer
bobbin 103, and thereby the heat dissipating property of the inner
winding 106 can be improved.
[0160] It should be noted that, in embodiment 4, the shape
described with reference to FIG. 15 may be adopted for the shape of
the ends of the first and second bobbin members 103M and 103N. The
same effect can be obtained by means of these shapes. Furthermore,
the ends of the first and second bobbin members 103M and 103N may
have engaging parts 103 such as those described with reference to
FIGS. 9 and 10. The same effect can be obtained by means of these
shapes. Furthermore, a shape such as that depicted in FIG. 11 may
be adopted also for the shape of the transformer 101D in embodiment
4. The same effect can be obtained also with this shape.
[0161] As described above, in embodiment 4, the gaps 105 are
provided at corners of the outer bobbin 103. In embodiment 4, the
contact area between the inner winding 106 and the outer bobbin 103
thereby increases compared to embodiment 1. Therefore, according to
embodiment 4, the heat dissipating property can be further improved
compared to embodiment 1.
[0162] The outer bobbin 103 and linear portions (e.g., long areas
and short areas) of the inner winding 106 are in close contact.
With this configuration, bending is less likely to occur in the
outer bobbin 103 even in the case where winding pressure is applied
to the outer bobbin 103 when the outer winding 104 is wound around
the outer bobbin 103. Therefore, the possibility of the outer
bobbin 103 breaking can be reduced.
[0163] The distance between the inner winding 106 and the outer
winding 104 is fixed to correspond to the thickness of the outer
bobbin 103. It is therefore possible to reduce variation in leakage
inductance. Furthermore, a bobbin having a structure same as or
similar to the outer bobbin 103 may be additionally arranged
outside of the outer winding 104. It is thereby possible to also
improve the heat dissipating property of the outer winding 104.
[0164] The transformer 101D may not have the core 107.
[0165] The core 107 depicted in FIG. 18 is made up of the two
E-shaped cores 107A and 107B, but there is no restriction thereto.
The core 107 may be made up of four squared U-shaped cores, for
example. Alternatively, the core 107 may be made up of an E-shaped
core and an I-shaped core.
[0166] In the example depicted in FIG. 19, the winding axis of the
inner winding 106 and the winding axis of the outer winding 104 are
shared, but there is no restriction thereto, and a central axis
that is different from the inner winding 106 and the outer winding
104 may be shared.
Embodiment 5
[0167] A designer can design various bobbins on the basis of the
design principles described in relation to embodiment 1. In
embodiment 5, a magnetic device provided with an inner bobbin made
up of two bobbin members arranged with gaps therebetween, and an
outer bobbin made up of two bobbin members arranged with gaps
therebetween is described.
[0168] FIG. 20 is an exploded perspective view of a transformer
101E according to embodiment 5. FIG. 21 is a cross-sectional view
along an XY plane perpendicular to the winding axis direction of
the transformer 101E. It should be noted that a cross-sectional
view along a YZ plane that includes the winding axis of the
transformer 101E is the same as FIG. 2. The structure of the
transformer 101E of embodiment 5 will be described using FIGS. 2,
20, and 21.
[0169] The transformer 101E is provided with a core 108, a core
109, an inner bobbin 102, an inner winding 106, an outer bobbin
103, and an outer winding 104.
[0170] The core 108 has a column portion 108A and a bottom portion
108B, and is formed in a T-shape when viewed from the X direction.
The core 109 has a side portion 109A and a top portion 109B, and is
formed in a squared U-shape when viewed from the X direction. The
cores 108 and 109 are formed of a magnetic material such as a
ferrite, a dust core, or an amorphous alloy. Hereinafter, the core
108 and the core 109 are sometimes collectively referred to as the
core 107.
[0171] The inner bobbin 102 is formed of an insulating resin, for
example. The inner bobbin 102 includes a first bobbin member 102X
and a second bobbin member 102Y. The first and second bobbin
members 102X and 102Y have the same shape, and are formed in a
squared U-shape when viewed from the Z direction.
[0172] One end of the first bobbin member 102X opposes one end of
the second bobbin member 102Y. The other end of the first bobbin
member 102X opposes the other end of the second bobbin member 102Y.
Gaps 105A are provided between the ends of the bobbin members in
the winding direction of the inner winding 106.
[0173] The first and second bobbin members 102X and 102Y each
include an inner column 102A extending in the winding axis
direction (i.e., Z direction), an inner upper flange 102B formed at
one end of the inner column 102A, and an inner lower flange 102C
formed at the other end.
[0174] The inner winding 106 is formed of a conductive wire such as
a single wire or a litz wire. The inner winding 106 is wound onto
the inner bobbin 102. As depicted in FIG. 21, the inner winding 106
is formed with the conductive wire being wound around, in a shape
having short areas parallel to the Y direction and long areas
parallel to the X direction.
[0175] The outer bobbin 103 is formed of an insulating resin, for
example. The outer bobbin 103 includes a first bobbin member 103X
and a second bobbin member 103Y. The first and second bobbin
members 103X and 103Y have the same shape, and are formed in a
squared U-shape when viewed from the Z direction.
[0176] The first and second bobbin members 103X and 103Y each
include an outer column 103A extending in the winding axis
direction (i.e., Z direction), an outer upper flange 103B formed at
one end of the outer column 103A, and an outer lower flange 103C
formed at the other end. In other words, the first and second
bobbin members 103X and 103Y are formed in the same manner as the
first and second bobbin members 103X and 103Y of embodiment 1
depicted in FIGS. 1 to 4.
[0177] The outer winding 104 is formed of a conductive wire such as
a single wire or a litz wire. The outer winding 104 is wound onto
the outer bobbin 103.
[0178] As depicted in FIG. 21, the gaps 105A in the inner bobbin
102 are respectively located beside the short areas of the inner
winding 106. Furthermore, the gaps 105 in the outer bobbin 103 are
respectively located beside the short areas of the inner winding
106.
[0179] When the transformer 101E is assembled, first, the inner
bobbin 102 is arranged by being made to slide from the Y direction
such that the inner column 102A of the inner bobbin 102 comes into
contact with the column portion 108A of the core 108. Next, the
inner winding 106 is wound onto the inner column 102A of the inner
bobbin 102. Next, the outer bobbin 103 is arranged by being made to
slide along the XY plane such that the outer column 103A comes into
contact with the inner winding 106. Next, the outer winding 104 is
wound onto the outer column 103A. Finally, the core 109 is arranged
such that the side portion 109A of the core 109 comes into contact
with the bottom portion 108B of the core 108 from the Z direction,
and the top portion 109B comes into contact with the column portion
108A.
[0180] By adjusting the size of the gaps 105A, the inner bobbin 102
can be brought into contact with the core 108 in an appropriate
manner even in the case where the size of the first and second
bobbin members 102X and 102Y with respect to the core 107 has
changed due to manufacturing variations. Consequently, heat of the
inner bobbin 102 can be suitably transmitted to the core 108. As a
result, heat absorbed from the inner winding 106 by the inner
bobbin 102 can be efficiently transmitted, and thereby the heat
dissipating property of the inner winding 106 can be improved.
[0181] According to embodiment 5, similar to embodiment 1, heat of
the inner winding 106 can be suitably transmitted to the outer
bobbin 103, and thereby the heat dissipating property of the inner
winding 106 can be improved.
[0182] It should be noted that the shape described with reference
to FIGS. 7 to 10 may be adopted for the shape of the ends of the
first and second bobbin members 103X and 103Y in embodiment 5. The
same effect can be obtained by means of these shapes. Furthermore,
a shape such as that depicted in FIG. 11 may be adopted also for
the shape of the transformer 101E in embodiment 5. The same effect
can be obtained also with this shape.
[0183] The outer bobbin 103 and the linear portions (e.g., the long
areas) of the inner winding 106 are in close contact. With this
configuration, bending is less likely to occur in the outer bobbin
103 even in the case where winding pressure is applied to the outer
bobbin 103 when the outer winding 104 is wound around the outer
bobbin 103. Therefore, the possibility of the outer bobbin 103
breaking can be reduced.
[0184] The distance between the inner winding 106 and the outer
winding 104 is fixed to correspond to the thickness of the outer
bobbin 103. It is therefore possible to reduce variation in leakage
inductance. Furthermore, a bobbin having a structure same as or
similar to the outer bobbin 103 may be additionally arranged
outside of the outer winding 104. It is thereby possible to also
improve the heat dissipating property of the outer winding 104.
[0185] The transformer 101E may not have the core 107.
[0186] The T-shaped core 108 and the squared U-shaped core 109 are
used in the example depicted in FIG. 20, but there is no
restriction thereto.
[0187] FIGS. 22 and 23 are perspective views schematically
depicting other example configurations of the core. FIG. 22 depicts
two cores 109 having a squared U-shape when viewed from the X
direction, and one core 110 having an I-shape (i.e., a planar plate
shape) when viewed from the X direction. As depicted in FIG. 23,
two cores 110A, two cores 110B, and one core 110C having an I-shape
(i.e., a planar plate shape) when viewed from the X direction may
be used.
[0188] In the example depicted in FIG. 21, the winding axis of the
inner winding 106 and the winding axis of the outer winding 104 are
shared, but there is no restriction thereto, and a central axis
that is different from the inner winding 106 and the outer winding
104 may be shared.
[0189] FIG. 24 is a cross-sectional view along an XY plane
perpendicular to the winding axis direction of a coil device 120
according to a modified example of embodiment 5. The coil device
120 is provided with an inner bobbin 102, an inner winding 106, and
a core 107. The inner bobbin 102 includes a first bobbin member
102X and a second bobbin member 102Y. The inner winding 106 is
wound onto the inner bobbin 102 and the core 107 is arranged to
thereby configure the coil device 120.
[0190] Due to the heat of the inner winding 106 being transmitted
to the core 107, the heat dissipating property can be improved even
with the coil device 120 in which, as in FIG. 24, an outer winding
is not wound. Similarly, various coil devices can be designed by
omitting the outer winding from the transformers described in the
various aforementioned embodiments. The present disclosure also
includes such coil devices.
Embodiment 6
[0191] FIG. 25 is a circuit diagram depicting an example of a
phase-shift full-bridge circuit 200. The phase-shift full-bridge
circuit 200 of FIG. 25 is widely used as a high-efficiency power
source circuit in various switching power sources, and chargers
such as an on-board charger, and power converters, for example. The
phase-shift full-bridge circuit 200 is an example of a power
conversion device.
[0192] The phase-shift full-bridge circuit 200 of FIG. 25 is
provided with a pair of connection terminals 211 and 212 that are
connected to an external direct-current power source, four
transistors 202, a transformer 101, a rectification circuit 204, a
smoothing inductance 209, and a smoothing capacitor 205. The
phase-shift full-bridge circuit 200 is further provided with a
resonance inductance 207 and a resonance capacitance 208. The
full-bridge circuit, which is made up of the four transistors 202,
is an example of a power conversion circuit. The rectification
circuit 204 is an example of a power conversion circuit.
[0193] The four transistors 202 are connected to a primary winding
of the transformer 101. The four transistors 202 have the same
configuration. The transistors 202 are metal-oxide film
semiconductor field effect transistors (MOSFETs) or insulated-gate
bipolar transistors (IGBTs), for example. The transistors 202 are
formed of gallium nitride (GaN) or silicon carbide (SiC), for
example.
[0194] The four transistors 202 are turned on and off alternately
such that the top-right and bottom-left transistors 202 are off
while the top-left and bottom-right transistors 202 are on, and the
top-right and bottom-left transistors 202 are on while the top-left
and bottom-right transistors 202 are off, for example. Due to this
switching, an alternating-current voltage is obtained from a
direct-current voltage 201 that is input to the pair of connection
terminals 211 and 212. This alternating-current voltage is input to
the primary winding of the transformer 101, and a voltage
corresponding to the ratio of the number of turns of the
transformer 101 is generated in a secondary winding of the
transformer 101. This generated voltage is rectified by the
rectification circuit 204 and smoothed by the smoothing inductance
209 and the smoothing capacitor 205, and a direct-current voltage
206 is thereby output.
[0195] In the phase-shift full-bridge circuit 200 of FIG. 25, in
order to suppress switching loss of the transistors 202, a zero
volt switching (ZVS) technique implemented by a resonance circuit
of the resonance inductance 207 and the resonance capacitance 208
is used, for example.
[0196] For example, in the case where the transformer 101 according
to embodiment 1 is adopted as the transformer 101 according to the
present embodiment, one from among the inner winding 106 and the
outer winding 104 may serve as the primary winding and the other
may serve as the secondary winding. Furthermore, in the phase-shift
full-bridge circuit 200 of the FIG. 25, any of the transformers
101A to 101E may be used instead of the transformer 101.
[0197] The phase-shift full-bridge circuit 200 of FIG. 25 is a
power source circuit for a comparatively large amount of power, and
therefore a large amount of heat is also generated from the
windings of the transformer and a core. Thus, the heat dissipating
property can be improved by using the transformers 101 and 101A to
101E. Furthermore, the weight of the circuit can be reduced in the
case where the resin molding is omitted or reduced in the
transformers 101 and 101A to 101E.
[0198] It should be noted that a transformer or a coil device
described in the various embodiments may be used for any of a
resonance inductance, a transformer, and a smoothing inductance,
and the same effect can be thereby obtained.
[0199] With regard to the power conversion device according to the
present embodiment, the example of the phase-shift full-bridge
circuit 200 depicted in FIG. 25 has been described, but there is no
restriction thereto.
[0200] FIG. 26 depicts an example of an LLC resonant half-bridge
circuit 300. The LLC resonant half-bridge circuit 300 is an example
of a power conversion device. For example, the transformer 101
according to embodiment 1 may be adopted as the transformer 101
according to the present embodiment.
[0201] A transformer or a coil device described in the various
embodiments may be used in an LLC resonant full-bridge circuit for
the power conversion device of the present disclosure.
Alternatively, a coil device described in the various embodiments
may be used in a magnetic device such as reactor or a choke
coil.
[0202] It should be noted that, in FIGS. 25 and 26, the resonance
inductance 207 may be realized by leakage inductance generated by
leakage flux that interlinks with only one of the inner winding 106
and the outer winding 104, and may be realized by external
inductance. In the case where the resonance inductance 207 is
realized with leakage inductance, external inductance is not
required, and therefore the size of the circuit can be reduced.
[0203] A magnetic device according to the present disclosure or a
power conversion device using the magnetic device can be applied in
various power source circuits for consumer appliances to on-board
chargers, for example.
* * * * *