Information
-
Patent Grant
-
6665414
-
Patent Number
6,665,414
-
Date Filed
Wednesday, September 27, 200024 years ago
-
Date Issued
Tuesday, December 16, 200320 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 381 396
- 381 397
- 381 407
- 381 410
- 381 412
- 381 414
- 381 419
- 381 420
- 310 16
-
International Classifications
-
Abstract
A speaker system and a cooling device therefor is provided which is capable of effectively dissipating heat generated by a voice coil. The cooling device is formed as a unitary member having a first member having a hollow cylindrical shape which is integrally formed with a second member having a hollow cylindrical shape which is concentric thereto and has a larger diameter than the first member, and a plurality of third members each in the form of a plate and radially arranged between the first member and the second member for connecting the members. The first member is arranged adjacent to the voice coil and at the same time inside a magnetic flux loop generated by a magnetic circuit, and the second member is arranged outside the magnetic flux loop, so that heat generated by the voice coil can be efficiently dissipated from the second member.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a speaker system and a cooling device therefor.
2. Description of the Related Art
Conventionally, a sound system for automobile use and the like has been actively high-powered, and accordingly, heat dissipation of the speaker system has been increasingly important.
FIGS. 1A and 1B
are diagrams each showing the construction of a conventional speaker. The construction of the speaker
10
will be briefly described with reference to these figures.
FIG. 1A
is a cross-sectional view showing essential parts of the speaker
10
.
FIG. 1B
is a cross-sectional view showing essential parts of the speaker
10
to which a cooling device
11
is attached.
Speaker
10
has a magnetic circuit including a disk-shaped bottom yoke
1
formed of a magnetic metal member and having a hollow cylindrical pole portion la, an annular magnet
2
placed on the bottom yoke
1
, and an annular top yoke
3
formed of a magnetic metal member and placed on the magnet
2
. Further, a diaphragm
7
with a dust cap
7
a
arranged at a center thereof is suspended on a frame
4
via an edge
5
and a damper
6
, and joined to a coil bobbin
9
having a voice coil
8
wound therearound. The coil bobbin
9
is arranged in a magnetic gap formed by the magnetic circuit.
The magnetic circuit has a magnetic path (indicated by arrows in the figures, for instance) formed by the bottom yoke
1
, the top yoke
3
, and the magnet
2
. A gap between an end of the pole portion la and the top yoke
3
forms the magnetic gap for collecting the magnetic flux of the magnet
2
and thereby generates a high-density uniform magnetic field. When a drive current is supplied to the voice coil
8
through a power amplifier circuit, not shown, the coil bobbin
9
arranged in the magnetic gap with predetermined spaces from the pole portion la and the top yoke
3
is actuated to perform a reciprocating motion by an electromagnetic force generated in the magnetic gap. The reciprocating motion is transmitted to the diaphragm
7
whereby sounds are emitted. In short, an electrical signal is converted to acoustic vibrations. In the case of speaker
10
, especially when a large drive current is continuously supplied, the voice coil
8
generates Joule heat to thereby increase the temperature of the whole magnetic circuit formed by the bottom yoke
1
and its associated components.
To eliminate the above inconvenience, it is possible to employ a method of fitting a cooling device
11
, which is formed by a disk-shaped member highly efficient in thermal conductivity, with a concentric groove formed therein, in the pole portion la of the bottom yoke
1
. That is, if the cooling device
11
formed with the groove in which the disk-shaped bottom yoke
1
can be fitted is used, heat from the magnetic circuit can be emitted simply by mounting the device
11
on the bottom yoke
1
of the speaker
10
, as shown in FIG.
1
B.
However, heat generated by the voice coil
8
is gradually transferred to the bottom yoke
1
and the top yoke
3
. Therefore, it takes time before the heat generated by the voice coil
8
is accumulated in the bottom yoke
1
and the top yoke
3
, which prevents effective transfer of heat from the voice coil
8
to the cooling device
11
.
OBJECTS AND SUMMARY OF THE INVENTION
The invention has been made in view of the above problems, and it is an object of the invention to provide a speaker system and a cooling device therefor which are capable of effectively dissipating heat generated by a voice coil.
To attain the above object, according to a first aspect of the invention, there is provided a speaker system including a magnetic circuit having a magnetic gap, a voice coil arranged in the magnetic gap, and a diaphragm attached to the voice coil, the voice coil and diaphragm being driven by supplying a drive current to the voice coil, comprising a first member arranged adjacent to the voice coil and inside a magnetic flux loop generated by the magnetic circuit, a second member arranged outside the magnetic flux loop generated by the magnetic circuit, and a third member connecting the first member and the second member to each other, wherein the first to third members are formed of a material excellent in thermal conductivity.
Preferably, the magnetic circuit is of an outer magnet type.
Preferably, the magnetic circuit is of an inner magnet type.
To attain the above object, according to a second aspect of the invention, there is provided a cooling device for a speaker system, comprising a first member arranged adjacent to a voice coil and inside a magnetic flux loop generated by a magnetic circuit, a second member arranged outside the magnetic flux loop generated by the magnetic circuit; and a third member connecting the first member and the second member to each other, wherein the first to third members are formed of a material excellent in thermal conductivity.
Preferably, heat generated in the voice coil is transferred to the second member via the first member and the third member to thereby allow the heat to be dissipated from the second member.
Preferably, the first to third members are integrally formed as a unitary member.
According to the speaker system and the cooling device therefor, the first member is arranged adjacent to the voice coil and at the same time inside the magnetic flux loop generated by the magnetic circuit, and the second member is arranged outside the magnetic flux loop, with the third member connecting the first member and the second member. Further, the first to third members are formed of a material excellent in thermal conductivity. Therefore, heat generated by the voice coil is transferred in the order of the first member, the third member, and the second member, thereby being dissipated from the second member.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A
is a cross-sectional view showing essential parts of a prior art speaker;
FIG. 1B
is a cross-sectional view showing essential parts of the
FIG. 1A
prior art speaker having a cooling device mounted thereon;
FIGS. 2A and 2B
are outline views of a cooling device for a speaker system according to an embodiment of the invention;
FIGS. 3A and 3B
are outline views of a bottom yoke for having the cooling device mounted thereon according to the embodiment of the invention;
FIGS. 4A and 4B
are outline views of the bottom yoke with the cooling device mounted thereon according to the embodiment of the invention;
FIG. 5
is a cross-sectional view of the speaker system having the cooling device mounted thereon, according to the embodiment of the invention;
FIGS. 6A and 6B
are outline views of a cooling device for a speaker system according to another embodiment of the invention; and
FIG. 7
is a cross-sectional view of an inner magnet type speaker system, to which the cooling device according to the embodiment of the invention is applied.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 2A and 2B
are outline views of a cooling device
20
for a speaker system, according to an embodiment of the invention. The cooling device
20
according to the embodiment of the invention is mounted on the inside of a bottom yoke
21
shown in
FIGS. 3A
,
3
B, and
FIGS. 4A
,
4
B. Therefore, not only the construction of the cooling device
20
but also that of the bottom yoke
21
will be described with reference to
FIGS. 2A
to
4
B. It should be noted that
FIGS. 2A and 2B
are outline views of the cooling device
20
,
FIGS. 3A and 3B
are outline views of the bottom yoke
21
of the speaker system, and
FIGS. 4A and 4B
are outline views of the bottom yoke
21
with the cooling device
20
attached thereto.
As shown in
FIGS. 2A and 2B
, the cooling device
20
is comprised of a first member
20
a
having a hollow cylindrical shape, a second member
20
b
having a hollow cylindrical shape, which is concentric with and has a larger diameter than the first member
20
a
, and a plurality of third members
20
c
each in the form of a plate, which are radially arranged between first member
20
a
and second member
20
b
for connecting first member
20
a
and second member
20
b
to each other. Further, the first member
20
a
and the third members
20
c
are welded to or integrally formed with each other, and the second member
20
b
and the third members
20
c
are also welded to or integrally formed with each other. All these members are formed of a material that is highly efficient in thermal conductivity, such as copper or the like.
FIGS. 2A and 2B
show an example of the cooling device
20
formed by the above-mentioned members integrally formed with each other.
As shown in
FIGS. 3A and 3B
, the bottom yoke
21
is comprised of a pole portion
21
a
having a hollow cylindrical shape, and a bottom board portion
21
b
having a disk shape. On an upper surface
21
d
of the bottom board portion
21
b
, a plurality of insertion grooves
21
c
for mounting the third members
20
c
of the cooling device
20
are radially arranged at positions corresponding to the respective third members
20
c.
The insertion grooves
21
c
of the bottom yoke
21
each have a depth approximately equal to the thickness of each of the third members
20
c
. Accordingly, when the cooling device
20
is mounted on the bottom yoke
21
, as shown in
FIGS. 4A and 4B
, the upper surface
21
d
of the bottom board portion
21
b
is at substantially the same level as an upper surface
20
d
of each of the third members
20
c
, so that when the annular magnet
2
as a component of the magnetic circuit is placed on the bottom yoke
21
, a bottom surface of the magnet
2
is brought into intimate contact with the upper surface
21
d
of the bottom board portion
21
b
and the upper surface
20
d
of each of the third members
20
c.
Next, the construction of a speaker system
30
incorporating the cooling device
20
according to the embodiment of the invention will be described with reference to FIG.
5
. It should be noted that reference numbers of the components which correspond to the prior art components are numbered in the same manner.
FIG. 5
shows the speaker system
30
including a magnetic circuit of an outer magnet type.
Referring to
FIG. 5
, the speaker system
30
includes a disk-shaped bottom yoke
21
with the pole portion
21
a
, which is formed of a magnetic metal member, and the cooling device
20
arranged at a predetermined position of the bottom yoke
21
. The first member
20
a
as a component of the cooling device
20
is arranged adjacent to a voice coil
8
of the speaker system and at the same time inside a magnetic flux loop of a magnetic circuit of the speaker system. Hence, the first member
20
a
is formed to have an inner diameter larger than an outer diameter of the voice coil
8
such that a predetermined magnetic gap can be obtained. Further, the second member
20
b
forming the cooling device
20
is arranged outside the magnetic flux loop of the magnetic circuit, so that the second member
20
b
is formed to have an inner diameter larger than an outer diameter of an annular magnet
2
. The annular magnet
2
and an annular top yoke
3
formed of a magnetic metal member are placed on the cooling device
20
to thereby form the magnetic circuit. Further, a diaphragm
7
with a dust cap
7
a
arranged at a center thereof is suspended on a frame
4
via an edge
5
and a damper
6
, and joined to a coil bobbin
9
. The coil bobbin
9
having a voice coil
8
wound therearound is arranged in a magnetic gap formed between the outer periphery of the pole portion
21
a
and the inner periphery of the top yoke
3
.
As described above, when the cooling device
20
is mounted on the bottom yoke
21
, the third members
20
c
are inserted into the insertion grooves
21
c
, and the upper surface
20
d
of the speaker system
20
is at substantially the same level as the upper surface
21
d
of the bottom yoke
21
. Further, when the annular magnet
2
is placed at a predetermined position of the cooling device
20
, most of the bottom surface of the magnet
2
is brought into intimate contact with the upper surface
21
d
of the bottom yoke
21
. That is, the third members
20
c
of the cooling device
20
are interposed between the magnet
2
and the bottom yoke
21
. By forming each of these third members
20
c
in the form of a plate and at the same time radially arranging the same, the magnetic flux density of the magnet
2
is prevented from being reduced. Therefore, the magnetic circuit constructed by fixedly attaching the top yoke
3
to the magnet
2
forms a magnetic path (indicated by arrows in the figure, for instance) extending from the magnet
2
, through the bottom board portion
21
b
and pole portion
21
a
of the bottom yoke
2
, to the top yoke
3
and a high-density uniform magnetic field is generated in the magnetic gap formed between the pole portion
21
a
and the top yoke
3
.
When a drive current is supplied to the voice coil
8
, the coil bobbin
9
arranged in the magnetic gap with predetermined spaces from the pole portion
21
a
and the top yoke
3
is actuated to perform a reciprocating motion by an electromagnetic force in the magnetic gap. When a large drive current is continuously supplied, the voice coil
8
generates Joule heat.
Since the speaker system
30
and the cooling device
20
therefor according to the invention are constructed such that the first member
20
a
is arranged adjacent to the voice coil
8
, heat generated by the voice coil
8
is quickly transferred to the first member
20
a
. The heat transferred to the first member
20
a
is then transferred to the second member
20
b
via the third members
20
c
. The second member
20
b
is cooled off by the outside air temperature since the second member
20
b
is arranged outside the magnetic flux loop of the magnetic circuit.
The second member
20
b
of the cooling device
20
is always cooled off by the outside air temperature to thereby cool off the third members
20
c
joined to the second member
20
b
. The third members
20
c
then cool off the first member
20
a
joined thereto. The voice coil
8
has a periphery thereof covered by the first member
20
a
arranged adjacent to the same and cooled off as described above, which makes it possible to hold down an increase in the temperature of the voice coil
8
.
FIGS. 6A and 6B
are outline views of a cooling device
22
for a speaker system according to another embodiment of the invention. A second member
22
b
of the cooling device
22
is arranged outside a magnetic flux loop of a magnetic circuit of the speaker system, so that if the cooling device
22
is used which is formed to have e.g. concave and convex portions
22
e
arranged on an outer peripheral surface of the second member
22
b
, as shown in
FIG. 6A
, or e.g. a fin
22
f
arranged on an outer periphery of the second member
22
b
, as shown in
FIG. 6B
, the speaker system
30
can be provided with increased heat dissipation.
FIG. 7
shows a speaker system
40
according to still another embodiment of the invention, which includes a magnetic circuit of an inner magnet type.
In the speaker system
40
of the inner magnet type, the cooling device
22
is mounted on a disk-shaped bottom yoke
23
. On the cooling device
22
is fixedly attached a top yoke
24
, while a magnet
26
is placed on a portion of the bottom yoke
23
inside the coil bobbin
9
, and further a center yoke
25
is fixedly attached to the magnet
26
, whereby a magnetic circuit is formed.
In the case of the speaker system
40
of the inner magnet type, similar to the speaker system of the outer magnet type, the first member
22
a
of the cooling device
22
is arranged adjacent to the voice coil
8
. Therefore, heat generated by the voice coil
8
is quickly transferred to the first member
22
a
, and then to the second member
20
b
via the third members
20
c
, thereby being cooled of f by the outside air temperature.
According to the speaker system and the cooling device of the invention, the first member is arranged adjacent to the voice coil
8
, and inside the magnetic flux loop of the magnetic circuit, while the second member is arranged outside the magnetic flux loop. Further, the first member and the second member are connected to each other by the third members, and the first to third members are formed of a material that is highly efficient in thermal conductivity. Therefore, heat generated by the voice coil can be efficiently dissipated from the second member.
While there have been described preferred embodiments of the present invention, it is to be understood that various modifications and variations will occur to those skilled in the art without departing from the spirit and scope of the invention as hereinafter claimed.
Claims
- 1. A speaker system including a magnetic circuit having a magnetic gap, a voice coil arranged in said magnetic gap, and a diaphragm attached to said voice coil and suspended on a frame, said voice coil and said diaphragm being driven by supplying a drive current to said voice coil, the speaker system comprising:a cooling device that includes: a first member arranged adjacent to said voice coil and inside a magnetic flux loop generated by said magnetic circuit; a second member arranged outside magnetic flux loop generated by said magnetic circuit; and a third member connecting said first member and said second member to each other, said third member disposed between said magnetic circuit and a yoke, wherein said first to third members are formed of a material that is efficient in thermal conductivity.
- 2. A speaker system according to claim 1, wherein said magnetic circuit is of an outer magnet type.
- 3. A speaker system according to claim 1, wherein said magnetic circuit is of an inner magnet type.
- 4. A speaker system according to claim 1, wherein the first member is sufficiently adjacent to the voice coil to promptly absorb a heat generated from the voice coil.
- 5. A speaker system according to claim 1, wherein the first member is an upright member.
- 6. A speaker system according to claim 5, wherein height of the first member is substantially the same as height of the voice coil.
- 7. A speaker system according to claim 1, wherein the first member surrounds the voice coil.
- 8. A speaker system according to claim 1, wherein the second member has concave and convex portions.
- 9. A speaker system according to claim 1, wherein the second member has fins.
- 10. A speaker system according to claim 1, said yoke comprising a bottom yoke and a top yoke, wherein said third member is disposed between said bottom yoke and said magnetic circuit.
- 11. A cooling device for a speaker system, comprising:a first member arranged adjacent to said voice coil and inside a magnetic flux loop generated by said magnetic circuit; a second member arranged outside magnetic flux loop generated by said magnetic circuit; and a third member connecting said first member and said second member to each other, said third member disposed between said magnetic circuit and a yoke, wherein said first to third members are formed of a material that is efficient in thermal conductivity wherein the cooling device is not a frame.
- 12. A cooling device according to claim 11, wherein heat generated by said voice coil is transferred to said second member via said first member and said third member to thereby allow said heat to be dissipated from said second member.
- 13. A cooling device according to claim 11, wherein said first to third members are integrally formed as a unitary member.
- 14. A cooling device for a speaker system according to claim 11, wherein the first member is sufficiently adjacent to the voice coil to promptly absorb a heat generated from the voice coil.
- 15. A cooling device for a speaker system according to claim 11, wherein the first member is an upright member.
- 16. A cooling device for a speaker system according to claim 15, wherein height of the first member is substantially the same as height of the voice coil.
- 17. A cooling device for a speaker system according to claim 11, wherein the first member surrounds the voice coil.
- 18. A cooling device for a speaker system according to claim 11, wherein the second member has concave and convex portions.
- 19. A cooling device for a speaker system according to claim 11, wherein the second member has fins.
- 20. A cooling device according to claim 11, said yoke comprising a bottom yoke and a top yoke, wherein said third member is disposed between said bottom yoke and said magnetic circuit.
- 21. A speaker apparatus comprising:a frame; a magnet unit supported by the frame for creating a magnetic circuit, the magnet unit having an upper yoke and a lower yoke; a bobbin supported by the frame such that at least part of the bobbin is present in the magnetic circuit, the bobbin having a generally cylindrical shape, the bobbin having a height direction and a radial direction; a voice coil arranged around the bobbin, the voice coil having a lower end and an upper end; a diaphragm attached to the voice coil and supported by the frame such that the diaphragm and the voice coil are driven by a drive current supplied to the voice coil; and a cooling device including: a first member extending in the height direction of the bobbin such that the first member is adjacent to the lower end of the voice coil; a second member extending outwardly from the first member in the radial direction of the bobbin, and third member extending from the second member in the height direction of the bobbin such that the third member stands in parallel to the first member.
- 22. A speaker apparatus according to claim 21, wherein the lower end of the voice coil is below the top yoke.
- 23. A speaker apparatus according to claim 21, wherein the third member extends between the top yoke and the bottom yoke.
- 24. A speaker apparatus according to claim 21, wherein the second member has concave and convex portions.
- 25. A speaker apparatus according to claim 21, wherein the second member has fins.
Priority Claims (1)
Number |
Date |
Country |
Kind |
11-312841 |
Sep 1999 |
JP |
|
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Name |
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Sakurai et al. |
Jul 1980 |
A |
4933975 |
Button |
Jun 1990 |
A |
5835612 |
Fujihira et al. |
Nov 1998 |
A |
6175637 |
Fujihira et al. |
Jan 2001 |
B1 |