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JPWO2016038812

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
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DESCRIPTION JPWO2016038812
Abstract A loudspeaker comprises a frame, a diaphragm, an edge, a magnetic circuit and a voice
coil body. The magnetic circuit has a magnet and a bottom plate. The bottom plate has an
installation portion and a plurality of arm portions. The installation portion is installed on the
first surface of the magnet and is magnetically coupled to the magnet. The plurality of arm
portions project from the installation portion toward the outer periphery and are coupled to the
frame.
Loudspeaker and mobile unit equipped with the same
[0001]
The present disclosure relates to an electrodynamic loudspeaker used for acoustic equipment
and a mobile device equipped with the same.
[0002]
A conventional loudspeaker comprises a frame, a diaphragm, a voice coil body and a magnetic
circuit.
The outer peripheral end of the diaphragm is connected to the frame via an edge. The magnetic
circuit has a magnetic gap and is coupled to the frame. The voice coil body has a bobbin and a
voice coil. A voice coil is wound around the first end of the bobbin. One end of the bobbin is
coupled to the diaphragm. The voice coil is disposed in the magnetic gap.
11-05-2019
1
[0003]
As prior art document information related to the invention of this application, for example,
Patent Document 1 is known.
[0004]
JP 2011-35812 A
[0005]
The loudspeaker comprises a frame, a diaphragm, an edge, a magnetic circuit and a voice coil
body.
[0006]
The frame has a cylindrical internal space.
[0007]
The diaphragm is disposed in the internal space of the frame.
[0008]
The edge connects the outer peripheral end of the diaphragm to the frame.
[0009]
The magnetic circuit has a magnet and a bottom plate.
[0010]
The bottom plate has an installation portion and a plurality of arm portions.
[0011]
The installation portion is installed on the first surface of the magnet and is magnetically coupled
to the magnet.
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[0012]
The plurality of arm portions project from the installation portion toward the outer periphery
and are coupled to the frame.
[0013]
The magnetic circuit is disposed in the inner space of the frame and has a magnetic gap.
[0014]
The voice coil body has a cylindrical bobbin and a voice coil.
[0015]
The voice coil is wound around at least a portion of the bobbin.
[0016]
The voice coil body is disposed at the center of the diaphragm so that the voice coil is disposed in
the magnetic gap.
[0017]
Further, a mobile device according to the present disclosure includes a main body, a drive
mounted on the main body, an amplifier mounted on the main body, and a loudspeaker
according to the present disclosure to which an output from the amplifier is supplied. And.
[0018]
FIG. 1 is a perspective view of a loudspeaker according to the present embodiment.
FIG. 2 is a front view of the loudspeaker in the present embodiment.
FIG. 3 is a cross-sectional view taken along line 3-3 of FIG.
FIG. 4 is a rear view of the loudspeaker according to the present embodiment.
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3
FIG. 5 is a perspective view of the frame of the loudspeaker in the present embodiment.
FIG. 6 is an enlarged sectional view of an essential part of the magnetic gap of the loudspeaker
according to the present embodiment.
FIG. 7 is a cross-sectional view showing a bonding point between the bottom plate and the yoke
of the loudspeaker in the present embodiment.
FIG. 8 is an enlarged view of the engaged portion of the frame of the loudspeaker in the present
embodiment.
FIG. 9 is an enlarged view of a fin formed on an arm portion of the loudspeaker in the present
embodiment.
FIG. 10 is an enlarged view of a fin formed on the installation portion of the loudspeaker in the
present embodiment.
FIG. 11 is a cross-sectional view of another loudspeaker in the present embodiment.
FIG. 12 is a cross-sectional view of yet another loudspeaker according to the present
embodiment.
FIG. 13 is a rear view of still another loudspeaker according to the present embodiment.
FIG. 14 is a conceptual view of a mobile device according to the present embodiment.
[0019]
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4
In the loudspeaker, in order to reduce the thickness, it is necessary to bring the diaphragm and
the magnetic circuit close to each other.
Also, two edges may be used instead of dampers to support the diaphragm on the frame.
If the shape of the frame or the magnetic circuit or the coupling between the frame and the
magnetic circuit is not properly set, the loudspeaker becomes thick.
[0020]
In addition, it is demanded that the frame be molded using a resin material in terms of
productivity and cost. However, the frame of the loudspeaker has many bends and requires an
opening to release the sound pressure (back pressure) from the rear surface of the diaphragm. As
a result, the shape of the loudspeaker becomes complicated, and it may be difficult to
manufacture using a resin material in terms of productivity and strength.
[0021]
Furthermore, loudspeakers are required in various forms depending on the application. The invehicle loudspeakers are installed, for example, in a narrow space such as a car dashboard, a
door or a ceiling. Therefore, in-vehicle loudspeakers installed at such places are required to be
thin. Hereinafter, the thin loudspeaker 51 according to the present embodiment will be described
with reference to the drawings. FIG. 1 is a perspective view of a loudspeaker 51 in the present
embodiment. FIG. 2 is a front view of the loudspeaker 51 in the present embodiment. FIG. 3 is a
cross-sectional view taken along line 3-3 of FIG. FIG. 4 is a rear view of the loudspeaker 51 in the
present embodiment. Here, the upward direction is a direction from the magnetic circuit 61 to
the diaphragm 53 in FIG. 3, and the downward direction is a direction from the diaphragm 53 to
the magnetic circuit 61. In FIG. 3, the upper direction is the front direction of the diaphragm 53,
and the lower direction is the rear direction of the diaphragm 53. In FIG. 4, the arm portion 91 is
formed by the arm portions 91A to 91D.
[0022]
The loudspeaker 51 includes a frame 52, a diaphragm 53, an edge 54, a magnetic circuit 61, and
a voice coil body 55.
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5
[0023]
The frame 52 has a cylindrical internal space 52D.
[0024]
The diaphragm 53 is disposed in the internal space 52 D of the frame 52.
[0025]
The edge 54 connects the outer peripheral end of the diaphragm 53 and the frame 52.
[0026]
The magnetic circuit 61 has a magnet 62 and a bottom plate 64.
[0027]
The bottom plate 64 has an installation portion 64A and a plurality of arm portions 91.
[0028]
The installation portion 64A is installed on the first surface of the magnet 62 and is magnetically
coupled to the magnet 62.
[0029]
The plurality of arm portions 91 project from the installation portion 64A toward the outer
periphery and are coupled to the frame 52.
[0030]
The magnetic circuit 61 is disposed in the inner space 52 D of the frame 52 and has a magnetic
gap 56.
[0031]
The voice coil body 55 has a cylindrical bobbin 55A and a voice coil 55B.
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6
[0032]
The voice coil 55B is wound around at least a part of the bobbin 55A.
[0033]
The voice coil body 55 is disposed at the central portion (thin portion 53A) of the diaphragm 53
so that the voice coil 55B is disposed in the magnetic gap 56.
[0034]
By the above configuration, the loudspeaker 51 can be thinned.
[0035]
Since the magnetic circuit 61 and the frame 52 are connected by a plurality of arm portions 91,
an opening is formed between the adjacent arm portions 91.
Therefore, the frame 52 does not have to form an opening for releasing the sound pressure from
the rear surface of the diaphragm 53.
Thus, the frame 52 can be of a simple shape.
Further, air is passed through the opening by the sound pressure from the rear surface of the
diaphragm 53.
Therefore, the air cooling effect of the magnetic circuit 61 is improved.
[0036]
Hereinafter, the loudspeaker 51 will be described in more detail.
FIG. 5 is a perspective view of the frame 52 of the loudspeaker 51 in the present embodiment.
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7
As shown in FIG. 5, the frame 52 has a base 52A and an attachment portion 52B.
The base 52A has a hollow cylindrical shape.
That is, the base 52A has a cylindrical internal space 52D.
The diaphragm 53 and the magnetic circuit 61 are disposed in the internal space 52D.
When the circular diaphragm 53 is used when viewed from the front, the shape of the base 52A
is preferably cylindrical.
The frame 52 may not have the attachment portion 52B.
However, when the frame 52 has the attachment portion 52B, the loudspeaker 51 can be
attached to a baffle plate (not shown) or the like by the attachment portion 52B.
Further, a screw hole may be formed in the mounting portion 52B. In this case, the loudspeaker
51 can be fixed by screwing to a baffle plate or the like by the mounting portion 52B. Therefore,
the frame 52 preferably has the attachment portion 52B.
[0037]
The loudspeaker 51 preferably further includes a terminal 57. Here, the positive electrode
terminal 57A and the negative electrode terminal 57B are collectively referred to as a terminal
57. The terminal 57 is fixed to the side surface of the base 52A of the frame 52.
[0038]
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8
As shown in FIG. 3, the diaphragm 53 has a thin portion 53A and a thick portion 53B. The thick
portion 53B is formed around the thin portion 53A. The thin portion 53A and the thick portion
53B constitute a recess 41. That is, the thick portion 53B is formed on the outer periphery of the
diaphragm 53. The recess 41 is formed at the center of the rear surface of the diaphragm 53.
The upper surface of the magnetic circuit 61 is disposed at a position facing the thin portion
53A.
[0039]
The thin portion 53A is thinner than the thick portion 53B. The upper surface of the magnetic
circuit 61 is disposed at a position facing the thin portion 53A. Therefore, the distance between
the upper surface of the magnetic circuit 61 and the front surface of the diaphragm 53 can be
reduced. Therefore, the thickness of the loudspeaker can be reduced. Further, since the thick
portion 53B is formed on the outer peripheral portion of the diaphragm 53, the strength of the
diaphragm 53 can be increased.
[0040]
FIG. 6 is an enlarged sectional view of an essential part of the magnetic gap 56 of the
loudspeaker 51 in the present embodiment. The voice coil body 55 has a bobbin 55A and a voice
coil 55B. The shape of the bobbin 55A is cylindrical. In addition, not only a cylinder but a square
tube etc. are included here with cylindrical shape. The voice coil 55B is wound around at least a
part of the bobbin 55A. One end of the bobbin 55A is coupled to the thin portion 53A of the
recess 41. In other words, the first end (front surface) of the bobbin 55A is coupled to the thin
portion 53A. The voice coil 55B is wound around the second end (rear surface) of the bobbin
55A. The voice coil 55 </ b> B is disposed in the magnetic gap 56. When a drive signal is
supplied to the voice coil 55B, the diaphragm 53 vibrates according to the direction and
magnitude of the drive signal. The diaphragm 53 is driven in the winding axis direction (vertical
direction in FIG. 3) of the voice coil 55B via the bobbin 55A.
[0041]
The first edge 54A and the second edge 54B are collectively referred to as an edge 54. The first
edge 54A and the second edge 54B connect the outer peripheral end of the diaphragm 53 and
the frame 52, respectively. The second edge 54B is preferably disposed on the opposite side of
11-05-2019
9
the first edge 54A in the thickness direction of the thick portion 53B.
[0042]
The terminal 57 is disposed between the first edge 54A and the second edge 54B in the
thickness direction of the diaphragm 53. The terminal 57 is connected to the connection wire 58
(gold wire). The connection line 58 is drawn to the rear surface side of the thin portion 53A of
the diaphragm 53 through the hole formed in the thick portion 53B. The start and end of the
wire of the voice coil 55B are connected to the connecting wire 58 on the bobbin 55A. A drive
signal for driving the loudspeaker 51 is supplied to the terminal 57. Then, the drive signal is
supplied to the voice coil 55B via the connection line 58.
[0043]
It is preferable that the frame 52 have an attaching part 52C. In this case, the outer
circumferences of the first edge 54A and the second edge 54B are pasted to the pasting portion
52C. Therefore, the attaching part 52C is formed at the end on the front side of the base 52A.
Furthermore, the sticking part 52C is formed on the inner peripheral surface of the base 52A so
as to protrude toward the center of the base 52A. The frame 52 is preferably formed of a
synthetic resin material. With this configuration, the attachment portion 52B, the attachment
portion 52C, and the base 52A can be easily formed integrally. Therefore, the productivity of the
frame 52 is excellent.
[0044]
The attaching part 52C preferably has an upper surface to which the outer peripheral part of the
first edge 54A is attached and a lower surface to which the second edge 54B is attached. With
this configuration, the first edge 54A and the second edge 54B can be connected to the frame 52
with high accuracy. Also, the distance between the first edge 54A and the second edge 54B is
stabilized. Therefore, distortion of the loudspeaker 51 can be reduced.
[0045]
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10
The attaching portion 52C is not limited to a configuration in which both the first edge 54A and
the second edge 54B are attached to the side surface of the diaphragm 53, and one of them may
be attached to the side surface of the diaphragm 53. Alternatively, the first edge 54A or the
second edge 54B may be directly attached to the inner circumferential surface of the base 52A.
[0046]
The outer peripheral end of the diaphragm 53 is connected to the frame 52 via the first edge
54A and the second edge 54B. The direction (vertical direction shown in FIG. 3) of the vibration
(amplitude) of the diaphragm 53 is orthogonal to the direction of the magnetic flux in the
magnetic gap 56. That is, the diaphragm 53 is displaced in the winding axis direction (vertical
direction in FIG. 3) of the voice coil 55B by the first edge 54A and the second edge 54B.
[0047]
The first edge 54 </ b> A is disposed on the front side of the diaphragm 53 with respect to the
center of the diaphragm 53 in the thickness direction. The second edge 54 </ b> B is disposed on
the rear surface side of the diaphragm 53 with respect to the center of the diaphragm 53 in the
thickness direction.
[0048]
The first edge 54A and the second edge 54B are preferably symmetrical to each other with
respect to a plane perpendicular to the winding axis direction of the voice coil 55B. By this
configuration, rolling of the diaphragm 53 can be suppressed. Furthermore, the occurrence of
distortion due to the asymmetry of the amplitude of the diaphragm 53 can be suppressed.
Furthermore, it is further preferable that the first edge 54A and the second edge 54B be formed
symmetrically with respect to the center of the diaphragm 53 in the thickness direction.
[0049]
Furthermore, it is preferable to couple the first edge 54A to the front surface of the diaphragm
53 and to couple the second edge 54B to the rear surface of the thick portion 53B. In this case,
11-05-2019
11
the coupling portion 72 is formed to be parallel to the front and rear surfaces of the diaphragm
53. This configuration can increase the distance between the first edge 54A and the second edge
54B. Therefore, the rolling of the diaphragm 53 can be further suppressed. Here, the coupling
portion 72 is a coupling portion between the diaphragm 53 and the edge 54 (see FIG. 2).
[0050]
The first edge 54A and the diaphragm 53 may be coupled from the end on the front surface side
of the side surface of the diaphragm 53 in a position away in the rear surface direction. This
configuration can make the loudspeaker 51 shown in FIG. 3 thinner.
[0051]
The diaphragm 53 is preferably molded of a foamed resin material. By this configuration, the
diaphragm 53 can be lightened. The front surface of the diaphragm 53 is preferably formed flat.
[0052]
The rear surface of the thin portion 53A is flat. In the thin portion 53A, the thickness of the
diaphragm 53 is uniform.
[0053]
It is preferable that the boundary between the thin portion 53A and the thick portion 53B be
gradually thickened toward the outer periphery of the diaphragm 53. That is, it is preferable to
have an inclined surface 53D in which the thickness gradually increases from the thin portion
53A toward the thick portion 53B. By this configuration, the strength of the diaphragm 53 is
further improved.
[0054]
11-05-2019
12
The core of the diaphragm 53 is preferably made of a foamed resin material. Further, the
diaphragm 53 preferably has a reinforcing material layer on at least one of the front surface and
the rear surface of the core material. As the reinforcing material layer, carbon, metal or the like is
used, for example. As a metal reinforcement layer, aluminum, titanium etc. are used, for example.
[0055]
As shown in FIG. 3, the top surface of the magnetic circuit 61 is preferably disposed on the front
side of the diaphragm 53 rather than the rear surface of the thick portion 53B. That is, a part of
the magnetic circuit penetrates into the thin portion 53A. The loudspeaker 51 can be made
thinner by this configuration.
[0056]
Further, it is preferable to form a tapered portion 65A on the side surface of the magnetic circuit
61. In this case, the inclined surface 53D is preferably formed to face the tapered portion 65A.
With this configuration, a distance is secured between the diaphragm 53 and the magnetic circuit
61 such that the diaphragm 53 can be displaced in the axial direction of the voice coil. Therefore,
the top surface of the magnetic circuit 61 can be disposed close to the front surface of the
diaphragm 53.
[0057]
The magnetic circuit 61 is preferably of the internal magnet type. By this configuration, the area
of the thin portion 53A can be reduced. Therefore, the strength of the diaphragm 53 can be
increased. The inner magnet type magnetic circuit 61 includes a magnet 62, a top plate 63, a
bottom plate 64, and a yoke 65. The magnet 62 has a columnar shape and is magnetized in the
upper and lower thickness direction. The top plate 63 has a plate shape and is disposed on the
top surface of the magnet 62. The bottom plate 64 has an installation portion 64A and an arm
portion 91. The magnet 62 is installed on the upper surface of the installation portion 64A. The
bottom plate 64 is magnetically coupled to the magnet 62. The yoke 65 is formed upward from
the outer peripheral end on the upper side of the installation portion 64A. The yoke 65 is
magnetically coupled to the magnet 62 via the bottom plate 64. The top plate 63, the installation
portion 64A, and the yoke 65 are made of a magnetic material. These can be made of, for
example, a hot-rolled steel plate (SPHC or SPHD).
11-05-2019
13
[0058]
FIG. 7 is a cross-sectional view showing a bonding position of the bottom plate 64 of the
loudspeaker 51 and the yoke 65 in the present embodiment. The bottom plate 64 and the yoke
65 are preferably bonded by an adhesive. And as shown in FIG. 7, you may form in the adhesive
surface of the bottom plate 64 and the yoke 65 the recessed part 66 which hold | stores an
adhesive agent. The recess 66 may be formed in at least one of the bottom plate 64 and the yoke
65. The recess 66 is, for example, a plurality of grooves having a V-shaped cross section. The
recess 66 is formed, for example, by knurling the bonding surface of at least one of the bottom
plate 64 and the yoke 65. When the adhesive agent is accumulated in the concave portion 66,
the bottom plate 64 and the yoke 65 can be firmly adhered in a state of being in close contact
with each other.
[0059]
The top plate 63 and the yoke 65 are magnetized to have different polarities by the magnet 62.
The inner peripheral surface of the yoke 65 is disposed to face the outer peripheral side surface
of the top plate 63. With this configuration, as shown in FIG. 3, a magnetic gap 56 is formed
between the inner peripheral surface of the yoke 65 and the outer peripheral side surface of the
top plate 63. For example, the top plate 63 is magnetized to the N pole, and the yoke 65 is
magnetized to the S pole. In this case, the magnetic flux in the magnetic gap 56 is directed from
the top plate 63 to the yoke 65.
[0060]
Preferably, a tapered portion 65A is formed on the side surface of the outer periphery of the
yoke 65. That is, the yoke 65 is tapered from the bottom plate 64 toward the tip. With this
configuration, on the side surface of the outer periphery of the magnetic circuit 61, a tapered
portion 65A that tapers from the lower surface to the upper surface is formed. The tapered
portion 65A may have a flat surface, a curved surface such as a circular arc, or a stepped shape.
Further, the tapered portion 65A may be formed by combining these shapes as appropriate.
[0061]
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14
Since the inclined surface 53D is thicker than the thin portion 53A, the strength of the
diaphragm 53 in the area where the inclined surface 53D is configured can be increased.
Therefore, the diaphragm 53 can suppress the deformation in the region where the inclined
surface 53D is formed. Therefore, even if the distance between the inclined surface 53D and the
tapered portion 65A is reduced, collision of the inclined surface 53D with the tapered portion
65A can be suppressed. As a result, since the thickness of the diaphragm 53 on the inclined
surface 53D can be increased, the strength of the diaphragm 53 is further improved.
[0062]
The shape of the magnetic circuit 61 as viewed from the front side is preferably circular. When
the circular magnetic circuit 61 is used, the shape of the magnet 62 is preferably cylindrical. The
top plate 63 preferably has a disk shape. In this case, the shape of the diaphragm 53 viewed
from the front side is preferably circular or elliptical.
[0063]
However, the shape of the magnetic circuit 61 viewed from the front side is not limited to a
circular shape, and may be an elliptical shape or a rectangular shape. When the elliptical
magnetic circuit 61 is used, it is preferable that the shape of the bobbin 55A and the top plate 63
viewed from the front side is an elliptical shape. In this case, it is preferable that the shape of the
diaphragm 53 seen from the front is an elliptical shape or a rectangular shape. When the
rectangular magnetic circuit 61 is used, it is preferable that the shape of the bobbin 55A and the
diaphragm 53 viewed from the front is also rectangular.
[0064]
The magnet 62 is preferably a neodymium magnet. The energy product of neodymium magnets
is large. Therefore, the desired magnetic flux density can be obtained in the magnetic gap 56, and
the thickness of the magnet 62 can be reduced. As a result, the thickness of the loudspeaker can
be reduced.
11-05-2019
15
[0065]
Next, the arm unit 91 will be described in detail. As shown in FIG. 4, the bottom plate 64 has an
installation portion 64 </ b> A and a plurality of arm portions 91. The arm portion 91 extends in
the outer peripheral direction from the installation portion 64A. The plurality of arm portions 91
are coupled to the frame 52. With this configuration, the magnetic circuit 61 is coupled to the
frame 52 through the arm portion 91.
[0066]
As shown in FIG. 4, it is preferable that the plurality of arm parts 91 have an engaging part 91 </
b> E formed at the tip. The engaging portion 91E is, for example, a convex portion such as a
protrusion. FIG. 8 is an enlarged view of the engaged portion 52E of the frame 52 of the
loudspeaker 51 in the present embodiment. As shown in FIG. 8, it is preferable that an engaged
portion 52 </ b> E be formed on the base 52 </ b> A of the frame 52. The engaged portion 52E
is, for example, a recess such as a groove or a notch. The engaging portion 91E of the arm
portion 91 is engaged with the engaged portion 52E of the frame 52.
[0067]
The engaging portion 91 E shown in FIG. 4 protrudes from the tip of the arm portion 91. The
width of the engaging portion 91E is narrower than the width of the arm portion 91. On the
other hand, as shown in FIG. 5, the engaged portion 52E is a hole formed at the lower end of the
outer side of the frame 52 (the side far from the diaphragm 53). As shown in FIG. 8, the engaged
portion 52E has an insertion port 52F and a locking portion 52G. The insertion port portion 52F
is wider than the width of the engaging portion 91E shown in FIG. The locking portion 52G is
formed behind the insertion port 52F so as to be continuous with the insertion port 52F.
Furthermore, the width of the locking portion 52G is wider than the insertion port portion 52F in
the circumferential direction of the base 52A.
[0068]
The engaging portion 91E shown in FIG. 4 is inserted from the insertion port portion 52F of the
engaged portion 52E shown in FIG. 8 to the locking portion 52G. Then, the engaging portions
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16
91E of all the arm portions 91 shown in FIG. 4 are respectively inserted to the locking portions
52G of the engaged portions 52E. Thereafter, the frame 52 is rotated in the circumferential
direction of the base 52A with respect to the magnetic circuit 61, whereby the engaging portions
91E are engaged with and engaged with the corresponding engaged portions 52E. The portion
where the engaging portion 91E (see FIG. 4) and the engaged portion 52E (see FIGS. 5 and 8) are
locked is preferably fixed by an adhesive. Thereby, it is possible to prevent the resonance of the
portion where the engaging portion 91E shown in FIG. 4 and the engaged portion 52E shown in
FIG. 5 are locked. Thus, the magnetic circuit 61 is coupled to the frame 52 via the arm 91.
[0069]
In FIG. 4, the bottom plate 64 has four arm parts 91A to 91D. The arm portions 91A to 91D
extend in four directions orthogonal to one another. An opening 92 is formed between the
adjacent arm portions 91. Thus, the sound pressure (back pressure) from the rear surface of the
diaphragm 53 can be prevented from interfering with the vibration of the diaphragm 53 by
providing the opening 92. また。 Since the opening 92 is provided, the magnetic flux of the
magnetic circuit 61 can also be prevented from leaking to the arm portion 91. Therefore, the
magnetic flux density in the magnetic gap 56 can be increased.
[0070]
It is preferable that the installation portion 64A and the arm portion 91 be integrally formed.
This configuration does not require a separate member for fixing the magnetic circuit 61 to the
frame 52, which is advantageous for thinning. Also, the bottom plate 64 can be manufactured
inexpensively. In addition, the installation part 64A and the arm part 91 are not limited to being
integrally formed, and may be separately manufactured and connected. In this case, the
installation portion 64A may be made of a magnetic material, and the arm portion 91 may be
made of a nonmagnetic material. With this configuration, it is possible to suppress the generation
of the leakage magnetic field in the arm portion 91. Therefore, the magnetic flux density in the
magnetic gap 56 can be increased.
[0071]
FIG. 9 is an enlarged view of a fin 93 formed on the arm portion 91 of the loudspeaker 51 in the
present embodiment. As shown in FIG. 9, fins 93 may be provided on the outer periphery of the
11-05-2019
17
arm portion 91. By providing the fins 93, the surface area of the arm portion 91 is increased. As
a result, the magnetic circuit 61 dissipates heat more efficiently.
[0072]
FIG. 10 is an enlarged view of the fin 94 formed on the installation portion 64A of the
loudspeaker 51 in the present embodiment. As shown in FIG. 10, the bottom plate 64 may have
fins 94 on the outer periphery of the installation portion 64A. The fins 94 increase the surface
area of the bottom plate 64. Therefore, the magnetic circuit 61 dissipates heat efficiently.
[0073]
Since the bottom plate 64 can be formed of a flat metal plate, the fins 93 and 94 can be
integrally formed with the bottom plate 64 by sheet metal processing. Therefore, the loudspeaker
51 of the present embodiment is excellent in productivity.
[0074]
The base 52A of the frame 52 is formed in a tubular shape. The base 52A can have a simple
shape having no bent portion or an opening for releasing the back pressure of the diaphragm.
That is, in the present embodiment, the frame 52 can have a simple shape.
[0075]
The magnetic circuit 61 is not limited to the inner magnet type, and may be an outer magnet
type or a combination of an inner magnet type and an outer magnet type. FIG. 11 is a crosssectional view of another loudspeaker 251 in the present embodiment. In the loudspeaker 251,
the same components as those of the loudspeaker 51 are denoted by the same reference
numerals, and the description thereof is omitted.
[0076]
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18
The loudspeaker 251 has an outer magnet type magnetic circuit 81 instead of the inner magnet
type magnetic circuit 61. The magnetic circuit 81 includes a magnet 82, a top plate 83, and a
bottom plate 84. The bottom plate 84 has an installation portion 84A and a center pole 84B. The
shape of the magnet 82 is annular. The center pole 84B is formed at the center of the installation
portion 84A so as to project upward from the installation portion 84A. The magnet 82 is
mounted on the upper surface of the installation portion 84A outside the center pole 84B.
Further, a top plate 83 is mounted on the top surface of the magnet 82. The top plate 83 is also
annular. Further, the side surface of the outer periphery of the center pole 84B and the side
surface of the inner periphery of the top plate 83 are disposed to face each other. A magnetic
gap 56 is formed between the outer peripheral side surface of the center pole 84 B and the inner
peripheral side surface of the top plate 83.
[0077]
When the external magnet type magnetic circuit 81 is used, the center pole 84 B corresponds to
a yoke disposed to face the top plate 83.
[0078]
Also in this case, the magnetic circuit 81 is disposed at a position facing the thin portion 53A.
Therefore, the loudspeaker 251 can be thinned even by using the external magnet type magnetic
circuit 81.
[0079]
Here, it is preferable that a tapered portion 65A be formed on the side surface of the outer
periphery of the top plate 83. And it is preferable that the taper part 65A and the inclined
surface 53D of the recessed part 41 are arrange | positioned facing each other. The magnet 82
may be a bonded magnet. By using the bond magnet, the degree of freedom of the shape of the
magnet 82 is increased. And it is preferable that the taper part 65A is formed also in the side of
the perimeter of magnet 82. It is preferable that the tapered portion 65A and the inclined surface
53D be disposed to face each other.
11-05-2019
19
[0080]
FIG. 12 is a cross-sectional view of still another loudspeaker 151 in the present embodiment. FIG.
13 is a rear view of still another loudspeaker 151 in the present embodiment. In the loudspeaker
151, the same components as those of the loudspeakers 51 and 251 are denoted by the same
reference numerals, and the description thereof is omitted. The loudspeaker 151 has a magnetic
circuit 161 and a pedestal 152 in place of the magnetic circuit 61 of the loudspeaker 51. The
pedestal 152 has a mounting portion 152A and an arm portion 153.
[0081]
The magnetic circuit 161 includes a magnet 62, a top plate 63, and a bottom plate 164. The
bottom plate 164 has an installation portion 64A and a yoke 65. In this case, the shape of the
bottom plate 164 is a cylindrical shape having a bottom. Preferably, the mounting portion 64A
and the yoke 65 are integrally formed.
[0082]
The mounting portion 152A is provided at the central portion of the pedestal 152. The magnetic
circuit 161 is mounted on the upper surface of the mounting portion 152A and fixed to the
pedestal 152. The magnetic circuit 161 may be fixed to the pedestal 152 by screwing, for
example. The magnetic circuit 161 is not limited to being fixed to the pedestal 152 by a screw,
and may be fixed to the pedestal 152 by an adhesive or the like.
[0083]
Here, the magnetic saturation of the bottom plate 164 tends to occur at a position below the
outer peripheral side surface of the magnet 62. Therefore, the mounting portion 152A is
preferably a magnetic material. The mounting portion 152A is made of, for example, a hot-rolled
steel plate (SPHC, SPHD, etc.). In this case, the mounting portion 152A also functions as a
magnetic path in the magnetic circuit 161. By this configuration, the magnetic resistance in the
region under the outer peripheral side surface of the magnet 62 is reduced. Therefore, saturation
of magnetism in the magnetic circuit 161 is suppressed. As a result, the magnetic flux density of
the magnetic gap 56 can be increased.
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[0084]
The pedestal 152 has an arm portion 153 extending in the outer circumferential direction from
the mounting portion 152A. The tip of the arm portion 153 is fixed to the frame 52. Therefore,
the magnetic circuit 161 is fixed to the frame 52. The mounting portion 152A and the arm
portion 153 are preferably integrally formed. In addition, the mounting part 152A and the arm
part 153 are not restricted to the structure integrally formed, You may produce separately,
respectively, and may assemble them. In this case, the arm portion 153 is preferably formed of a
nonmagnetic material. This configuration can suppress the magnetic flux of the magnetic circuit
161 from leaking to the arm portion 153 side.
[0085]
The pedestal 152 preferably has a plurality of arm portions 153. And it is preferable that each
arm part 153 is arrange | positioned at equal intervals. In FIG. 13, six arm portions 153 </ b> A
to 153 </ b> F radially extending in the outer peripheral direction from the mounting portion
152 </ b> A are shown. In this case, it is preferable that the respective arm portions 153A to
153F be arranged at an angle of 60 degrees from the center of the mounting portion 152A.
When the magnetic circuit 161 is coupled to the frame 52 by the plurality of arms 153, an
opening 92 is formed between the adjacent arms 153. By providing the opening 92, it is possible
to suppress that the sound pressure (back pressure) from the rear surface of the diaphragm 53
interferes with the vibration of the diaphragm 53.
[0086]
Further, similarly to the arm portion 91, the arm portion 153 preferably has an engaging portion
91E engaged with the frame 52 at the tip. The frame 52 preferably has an engaged portion 52E
that engages the engaging portion 91E. The engaging portion 91E is, for example, a convex
portion such as a protrusion. The engaged portion 52E is, for example, a recess such as a groove
or a notch. Then, the pedestal 152 may be fixed to the frame 52 by fitting the convex portion
into the concave portion.
[0087]
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Furthermore, as shown in FIG. 9, the arm portion 153 may be provided with fins 93 around its
periphery. The provision of the fins 93 increases the surface area and / or volume of the arm
portion 153. As a result, the magnetic circuit 161 dissipates heat more efficiently.
[0088]
Since the pedestal 152 can be formed of a flat metal plate, the fins 93 can be integrally formed
by sheet metal processing, and the productivity is excellent. Moreover, as shown in FIG. 10, the
fin 94 may be formed in the outer periphery of the installation part 64A.
[0089]
FIG. 14 is a conceptual view of a mobile device 201 in the present embodiment. The mobile
device 201 has a loudspeaker 500 mounted thereon. Here, the loudspeaker 500 is the
loudspeaker 51, the loudspeaker 151, or the loudspeaker 251 of the present embodiment.
Although FIG. 14 shows a car as an example, the mobile device 201 is not limited to a car, and
may be a ship, an aircraft, a train, a motorcycle or the like.
[0090]
The mobile device 201 has a main body portion 202, a drive portion 203, an amplification
portion 211, and a loudspeaker 500. The drive unit 203, the amplification unit 211, and the
loudspeaker 500 are mounted on the main body unit 202. The drive unit 203 may have an
engine, a motor, a tire, a steering wheel, and the like. The output of the amplification unit 211 is
supplied to the loudspeaker 500. The amplification unit 211 may have part of a car audio. In that
case, the amplification unit 211 may have a reproduction device of a sound source or the like.
Furthermore, the amplification unit 211 may have a part of a car navigation system. In that case,
the amplification unit 211 may have a display device or the like.
[0091]
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The main body section 202 has a boarding space 202A. Loudspeaker 500 is installed to emit
sound to boarding space 202A. The main body portion 202 may further include an exterior
portion 202B and an interior portion 202C. The exterior portion 202B isolates the passenger
space 202A from the outside. The exterior portion 202B is, for example, a roof 202D or a door
202E. The interior portion 202C is provided between the exterior portion 202B and the boarding
space 202A. Loudspeaker 500 is housed between interior part 202C and exterior part 202B. The
place where the loudspeaker 500 is installed is not limited to the above, and may be a dashboard,
a rear tray (not shown), or the like.
[0092]
Since the loudspeaker 500 of this embodiment is thin, the distance between the interior 202C
and the exterior 202B can be shortened. In other words, even if the space between the interior
part 202C and the exterior part 202B is narrow, the loudspeaker 500 can be installed. Thus, by
using the loudspeaker 500 for the mobile device 201, the passenger space 202A can be
expanded.
[0093]
The embodiment described above is for facilitating the understanding of the present invention,
and the material and shape of each component constituting the loudspeaker 500 described in the
embodiment can be changed variously, and the present invention It is not for the purpose of
limiting interpretation.
[0094]
The present invention can be changed and improved without departing from the gist thereof, and
the present invention also includes the equivalents thereof.
[0095]
As described above, in the loudspeaker of the present disclosure, the magnetic circuit is disposed
in the internal space of the frame.
Further, a plurality of arm portions are coupled to the frame.
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And each arm part is protruded and provided toward the outer periphery of a magnetic circuit.
Thus, the loudspeaker can be made thinner. Further, since a plurality of arm portions are used to
couple the magnetic circuit and the frame, an opening is formed between the adjacent arm
portions. Therefore, it is not necessary to form an opening in the frame for releasing the sound
pressure from the rear surface of the diaphragm. Therefore, it is advantageous to make the frame
a simple shape. Also, the sound pressure from the rear surface of the diaphragm causes air to
pass through the opening. Therefore, the air cooling effect of the magnetic circuit is improved.
[0096]
The loudspeaker according to the present disclosure has the effect of being able to be thin, and is
particularly useful for in-vehicle audio devices and home audio devices.
[0097]
DESCRIPTION OF SYMBOLS 41 recessed part 51 loudspeaker 52 frame 52A base 52B
attachment part 52C attachment part 53 diaphragm 53A thin part 53B thick part 53D inclined
surface 54 edge 54A 1st edge 54B 2nd edge 55 voice coil body 55A bobbin 55B voice coil 56
magnetic coil Gap 57 terminal 57A positive terminal 57B negative terminal 58 connecting wire
61 magnetic circuit 62 magnet 63 top plate 64 bottom plate 64A setting portion 65 yoke 65A
tapered portion 66 concave portion 72 coupling portion 81 magnetic circuit 82 magnet 83 top
plate 84 bottom plate 84A setting portion 84B Center pole 91 arm portion 91A arm portion 91B
arm portion 91C arm portion 91D arm portion 91E engagement portion 92 opening 93 fin 151
loudspeaker 152 pedestal 152A mounting portion 15 Arm portion 153A Arm portion 153B Arm
portion 153C Arm portion 153D Arm portion 153E Arm portion 153F Arm portion 153G Arm
portion 161 Magnetic circuit 164 Bottom plate 201 Moving body device 202 Main body portion
202A Boarding space 202B Exterior portion 202C Interior portion 202D Roof 202E door 202E
Driver 211 Amplifier 251 Loudspeaker 500 Loudspeaker
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