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JPWO2016002230

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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 JPWO2016002230
Abstract A loudspeaker comprises a diaphragm, a voice coil body, and a magnetic circuit. The
first surface of the diaphragm is a surface of a recess formed of a thin portion and a thick portion
formed around the thin portion. The voice coil body has a bobbin and a voice coil. The bobbin
has a first end connected to the thin portion of the first surface of the diaphragm and a second
end formed opposite to the first end. The magnetic circuit has an inner portion, an outer portion,
and a magnetic gap. A portion having a first surface of the inner portion is disposed within the
bobbin from a second end of the bobbin such that the voice coil is disposed within the magnetic
gap, and the first surface of the inner portion and the first of the outer portion One side is
disposed in the recess.
Loudspeaker and mobile unit equipped with the same
[0001]
The present disclosure relates to a loudspeaker used for audio equipment. And a mobile device
equipped with the same.
[0002]
A conventional flat loudspeaker has a frame, a flat diaphragm, a voice coil body, and a magnetic
circuit. 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 a bobbin. One end of the bobbin is
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coupled to the flat diaphragm. The voice coil is disposed in the magnetic gap.
[0003]
The outer peripheral end of the planar diaphragm is connected to the frame via an edge. The flat
diaphragm is plate-like. That is, both surfaces (both front and rear surfaces) of the flat diaphragm
are flat.
[0004]
As prior art document information related to the invention of this application, for example,
Patent Document 1 is known.
[0005]
JP-A-56-56095
[0006]
The loudspeaker of the present disclosure includes a frame, a diaphragm, a first edge, a second
edge, a voice coil body, and a magnetic circuit.
[0007]
The frame has a hollow portion.
[0008]
The diaphragm has a first surface and a second surface opposite to the first surface, and is
disposed in the hollow portion of the frame.
The first surface of the diaphragm is a surface of a recess formed of a thin portion and a thick
portion formed around the thin portion.
[0009]
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The first edge connects the outer peripheral end of the diaphragm to the frame.
[0010]
The second edge is disposed on the opposite side of the first edge with respect to the center in
the thickness direction of the thick portion, and connects the outer peripheral end of the
diaphragm and the frame.
[0011]
The voice coil body has a bobbin and a voice coil.
The bobbin is cylindrical and has a first end connected to the thin portion of the first surface of
the diaphragm and a second end formed on the opposite side of the first end.
The voice coil is wound around at least a portion of the bobbin.
[0012]
The magnetic circuit has an inner portion, an outer portion, and a magnetic gap.
The outer side is formed around the inner side.
A magnetic gap is formed between the inner and outer portions.
A portion having a first surface of the inner portion is disposed within the bobbin from a second
end of the bobbin such that the voice coil is disposed within the magnetic gap, and the first
surface of the inner portion and the first of the outer portion One side is disposed in the recess.
[0013]
Further, a mobile device according to the present disclosure includes a main body, a drive unit
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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.
[0014]
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 an enlarged cross-sectional view of a main part of the
magnetic gap of the loudspeaker in the present embodiment. FIG. 5 is an enlarged sectional view
of an essential part of the edge of the loudspeaker according to the present embodiment. FIG. 6 is
an enlarged sectional view of an essential part of another edge of the loudspeaker according to
the present embodiment. FIG. 7 is an enlarged sectional view of an essential part of still another
edge of the loudspeaker according to the present embodiment. FIG. 8 is an enlarged sectional
view of an essential part of a diaphragm of a loudspeaker according to the present embodiment.
FIG. 9 is a rear view of the loudspeaker according to the present embodiment. FIG. 10 is a crosssectional view of another loudspeaker in the present embodiment. FIG. 11 is a cross-sectional
view of yet another loudspeaker according to the present embodiment. FIG. 12 is a crosssectional 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.
[0015]
In a conventional loudspeaker, in order to reduce the thickness, it is necessary to use a thin
diaphragm. However, using a thin diaphragm weakens the rigidity of the diaphragm.
[0016]
Alternatively, in order to make the loudspeaker thin, it is necessary to shorten the bobbin in the
direction of the winding axis of the voice coil or to use a thin magnetic circuit. In this case, the
magnetic flux density in the magnetic gap is reduced. Therefore, the sound pressure level of the
sound output from the loudspeaker decreases.
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[0017]
Loudspeakers require various forms depending on the application. The in-vehicle loudspeakers
are installed, for example, in a narrow space such as a car dashboard, a door, and a ceiling. In
order to install in such a place, a thin vehicle-mounted loudspeaker is required. 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 an enlarged sectional view of an essential part of the
magnetic gap 56 of the loudspeaker 51 in the present embodiment.
[0018]
The loudspeaker 51 includes a frame 52, a diaphragm 53, a first edge 54A, a second edge 54B, a
voice coil body 55, and a magnetic circuit 61.
[0019]
The frame 52 has a hollow portion 300.
[0020]
The diaphragm 53 has a first surface and a second surface opposite to the first surface, and is
disposed in the hollow portion 300 of the frame 52.
The first surface of the diaphragm 53 is the surface of a recess 53A formed of a thin portion 53C
and a thick portion 53B formed around the thin portion 53C.
[0021]
The first edge 54 </ b> A connects the outer peripheral end of the diaphragm 53 and the frame
52.
[0022]
The second edge 54B is disposed on the opposite side of the first edge 54A across the center of
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the thick portion 53B in the thickness direction, and connects the outer peripheral end of the
diaphragm 53 and the frame 52.
[0023]
The voice coil body 55 has a bobbin 55A and a voice coil 55B.
The bobbin 55A is cylindrical, and has a first end connected to the thin portion 53C of the first
surface of the diaphragm 53, and a second end formed on the opposite side of the first end.
The voice coil 55B is wound around at least a part of the bobbin 55A.
[0024]
The magnetic circuit 61 has an inner portion 400, an outer portion 450, and a magnetic gap 56.
The outer side 450 is formed around the inner side 400. The magnetic gap 56 is formed between
the inner portion 400 and the outer portion 450.
[0025]
A portion of the inner portion 400 having the first surface (upper surface in FIG. 3) is disposed in
the bobbin 55A from the second end of the bobbin 55A such that the voice coil 55B is disposed
in the magnetic gap 56. The first surface of the inner portion 400 and the first surface of the
outer portion 450 are disposed in the recess 53A.
[0026]
In FIG. 3, the inner portion 400 of the magnetic circuit 61 is composed of the magnet 62 and the
top plate 63, and the outer portion 450 of the magnetic circuit 61 is composed of the yoke 65.
[0027]
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Hereinafter, the loudspeaker 51 will be described in detail.
A magnetic gap 56 is formed on the upper side of the magnetic circuit 61.
The magnetic circuit 61 is fixed to the frame 52 (described later with reference to FIG. 9). 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.
[0028]
The diaphragm 53 has a thin portion 53C and a thick portion 53B. The thick portion 53B is
formed around the thin portion 53C. The thin portion 53C and the thick portion 53B constitute a
recess 53A. That is, the thick portion 53B is formed on the outer periphery of the diaphragm 53.
The top surface of the magnetic circuit 61 is disposed at a position facing the thin portion 53C.
[0029]
As shown to FIG. 3, FIG. 4, the voice coil body 55 has the bobbin 55A and the 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 53C of the recess 53A. In
other words, the first end (front surface) of the bobbin 55A is coupled to the thin portion 53C.
The voice coil 55B is wound around the second end (rear surface) of the bobbin 55A. The voice
coil 55 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 vibrates in the winding axis direction (vertical direction in FIG. 3) of the voice coil
55B via the bobbin 55A.
[0030]
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As described above, the diaphragm 53 has the thin portion 53C thinner than the thick portion
53B at the center of the rear surface. The upper surface of the magnetic circuit 61 is disposed at
a position facing the thin portion 53C. As a result, 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. In addition, since the thick portion 53B is formed
on the outer peripheral portion of the diaphragm 53, the diaphragm 53 with high strength can
be obtained.
[0031]
The loudspeaker 51 will be described in detail below. As shown in FIG. 1, the frame 52 has a base
52A and a mounting portion 52B. The base 52A has a hollow cylindrical shape. 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.
[0032]
As shown in FIG. 3, the loudspeaker 51 preferably further comprises a terminal 57. In the
present embodiment, 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 frame 52.
[0033]
FIG. 5 is an enlarged sectional view of an essential part of the edge 54 of the loudspeaker 51 in
the present embodiment. In the present embodiment, 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 disposed on the opposite side of the first edge 54A in the thickness direction
of the thick portion 53B.
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[0034]
The terminal 57 is disposed at a position 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 (cocoon wire). The connection line 58 is drawn to the rear surface side of the thin portion
53C 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 from the terminal 57 and transmitted to
the voice coil 55 B via the connection line 58.
[0035]
It is preferable that the frame 52 have an attaching part 52C. When the frame 52 has the
attaching part 52C, the outer periphery of the first edge 54A and the second edge 54B is
attached to the attaching part 52C. To that end, the attaching part 52C is formed at the end on
the front side of the base 52A. Further, the attaching 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 molded 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. That is, the
productivity of the frame 52 is excellent.
[0036]
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, a constant and stable distance is formed between the first edge 54A
and the second edge 54B. As a result, distortion of the loudspeaker 51 can be reduced.
[0037]
The attaching unit 52C is not limited to the configuration in which both the first edge 54A and
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the second edge 54B are attached, and either one may be attached. Alternatively, the first edge
54A or the second edge 54B may be directly attached to the inner circumferential surface of the
base 52A.
[0038]
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 of vibration (amplitude) of the diaphragm 53
(vertical direction of the arrow in FIG. 3) 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 of the voice
coil 55B by the first edge 54A and the second edge 54B.
[0039]
As shown in FIG. 5, the first edge 54A includes a first roll portion 71A and a first coupling
portion 72A. The second edge 54B includes a second roll portion 71B and a second coupling
portion 72B. The first coupling portion 72A and the second coupling portion 72B are coupled to
the diaphragm 53. In the present embodiment, the first roll portion 71A and the second roll
portion 71B are collectively referred to as a roll portion 71. Further, the first coupling portion
72A and the second coupling portion 72B are collectively referred to as a coupling portion 72.
[0040]
The first edge 54A is disposed on the front side of the diaphragm 53. In this case, the second
edge 54B is disposed on the rear surface side of the diaphragm 53. The first roll portion 71A
preferably protrudes in a direction away from the center of the diaphragm 53 in the thickness
direction. With this configuration, the first roll portion 71A and the second roll portion 71B are
prevented from colliding with each other regardless of the thickness of the diaphragm 53.
Therefore, the generation of the collision sound between the first roll portion 71A and the second
roll portion 71B is hindered.
[0041]
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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 (vertical direction in FIG. 3) of the
voice coil 55B. That is, it is preferable that the first edge 54A and the second edge 54B be
arranged to be symmetrical with respect to a plane perpendicular to the direction of the vibration
(amplitude) of the diaphragm 53. By this configuration, rolling of the diaphragm 53 is
suppressed. Furthermore, the occurrence of distortion due to the asymmetry of the amplitude of
the diaphragm 53 is suppressed. Further, it is more 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.
[0042]
Furthermore, it is preferable to couple the first edge 54A to the front surface of the thick portion
53B and to couple the second edge 54B to the rear surface of the thick portion 53B. In this case,
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.
[0043]
FIG. 6 is an enlarged sectional view of an essential part of another edge 54 of the loudspeaker 51
in the present embodiment. The coupling portion 72 is coupled to the side surface of the
diaphragm 53. In FIG. 6, the first edge 54A has a third coupling portion 72C instead of the first
coupling portion 72A. The second edge 54B has a fourth coupling portion 72D in place of the
second coupling portion 72B. The third coupling portion 72C extends along the side surface of
the diaphragm 53 from the first roll portion 71A. The fourth coupling portion 72D extends along
the side surface of the diaphragm 53 from the second roll portion 71B. The third coupling
portion 72C and the fourth coupling portion 72D are coupled at the side surface of the outer
periphery of the diaphragm 53. Preferably, the first edge 54A and the second edge 54B are
integrally formed. That is, it is preferable that the third joint 72C and the fourth joint 72D be
formed in a connected state. By this configuration, the first edge 54A and the second edge 54B
are maintained at a predetermined stable distance. Furthermore, the number of steps for
coupling the edge 54 to the diaphragm 53 is reduced.
[0044]
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Further, 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 at a position separated in the rear surface
direction. With this configuration, the loudspeaker 51 can be made thinner. The first edge 54A
and the second edge 54B are not limited to be coupled to the side surface of the diaphragm 53,
but one of the first edge 54A and the second edge 54B may be coupled to the side surface of the
diaphragm 53 May be
[0045]
FIG. 7 is an enlarged sectional view of an essential part of still another edge 54 of the
loudspeaker 51 in the present embodiment. The diaphragm 53 and the coupling portion 72 are
further coupled by another coupling method. The first edge 54A has a first coupling portion 72A
and a third coupling portion 72C. The second edge 54B has a second coupling portion 72B and a
fourth coupling portion 72D. That is, the first edge 54A is coupled to the front surface of the
diaphragm 53 and the side surface of the outer periphery. The second edge 54B is coupled to the
rear surface of the diaphragm 53 at the side surface of the outer periphery. By this configuration,
the area connecting the edge 54 and the diaphragm 53 is increased. Therefore, the strength of
coupling the edge 54 and the diaphragm 53 is improved. Therefore, even when a signal of a
large level is applied to the loudspeaker 51, peeling of the edge 54 from the diaphragm 53 can
be suppressed. As a result, the input resistance of the loudspeaker 51 can be increased.
[0046]
FIG. 8 is an enlarged sectional view of an essential part of diaphragm 53 of loudspeaker 51 in the
present embodiment. The recess 53A has a thin portion 53C. The thin portion 53C is thinner
than the thick portion 53B. The rear surface of the thin portion 53C is preferably flat. In the thin
portion 53C, the thickness of the diaphragm 53 is uniform. With this configuration, generation of
unnecessary resonance can be suppressed in the thin portion 53C.
[0047]
It is preferable that the boundary between the thin portion 53C and the thick portion 53B be
gradually thickened toward the outer periphery of the diaphragm 53. That is, the recess 53A
preferably has an inclined surface 53D in which the thickness gradually increases from the thin
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portion 53C to the thick portion 53B. By this configuration, the strength of the diaphragm 53 is
further improved. Furthermore, it is preferable that a corner is a chamfered surface or a curved
surface between the thin portion 53C and the inclined surface 53D. According to this
configuration, it is possible to alleviate the concentration of stress at the intersection of the thin
portion 53C and the inclined surface 53D. Therefore, the strength of the diaphragm 53 can be
increased.
[0048]
The shape of the inclined surface 53D may be a flat surface, a curved surface such as a circular
arc, or a stepped shape. Also, a combination of these may be used. Furthermore, the boundary
between the thin portion 53C and the thick portion 53B is not limited to the inclined surface
53D. For example, the boundary between the thin portion 53C and the thick portion 53B may be
formed perpendicularly to the thin portion 53C from the thin portion 53C toward the thick
portion 53B.
[0049]
The front surface of the diaphragm 53 is preferably flat. The diaphragm 53 may have a dust cap
at the center of the diaphragm 53.
[0050]
Here, it is preferable that the core 53E of the diaphragm 53 be formed of a foamed resin
material. By this configuration, the diaphragm 53 can be lightened. As a result, the response
characteristic of the diaphragm 53 is improved, and the sound velocity of the diaphragm 53 is
increased. Therefore, the rising of the sound becomes faster. In addition, the sound pressure level
of the sound output from the diaphragm 53 is improved, and the limit reproduction frequency in
the high region of the diaphragm 53 can also be increased.
[0051]
The diaphragm 53 may be made of only the core 53E, but it is preferable to have the core 53E
and the reinforcing material layer 53F.
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[0052]
The reinforcing material layer 53F is preferably formed on the front surface and the rear surface
of the core material 53E.
By this configuration, the strength of the diaphragm 53 is improved. The reinforcing material
layer 53F is preferably made of a hard and light material. Therefore, as the reinforcing material
layer 53F, for example, a metal layer such as aluminum or titanium, or a carbon layer is used.
With this configuration, the sound speed of the diaphragm 53 and the sound pressure level can
be increased. The reinforcing material layer 53F is not limited to the structure formed on both
the front surface and the rear surface of the core material 53E, and may be formed on any one of
the front surface and the rear surface of the core material 53E.
[0053]
The reinforcing material layer 53F may be formed by attaching a sheet-like reinforcing material
to the core material 53E with an adhesive or the like. When the diaphragm 53 is circular, the
shape of the recess 53A as viewed from the rear surface is also circular. In this case, the shape of
the surface of the inclined surface 53D is conical. However, when attaching a reinforcing material
to conical inclined surface 53D, a wrinkle may arise in reinforcing material layer 53F. Therefore,
when the reinforcing material is provided by adhesion, it is preferable to form the reinforcing
material layer 53F also on the rear surface of the thin portion 53C and the rear surface of the
thick portion 53B. This configuration can suppress the occurrence of wrinkles in the reinforcing
material layer. In addition, the number of steps for attaching the reinforcing material to the core
material can be reduced.
[0054]
In the diaphragm 53, the strength of the diaphragm 53 can be efficiently improved by increasing
the strength of the thin portion 53C. Therefore, the reinforcing material layer on the rear surface
may be formed only in the recess 53A or the thin portion 53C. By this configuration, the
diaphragm 53 can be lightened.
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[0055]
In addition, the formation method of the reinforcement material layer 53F is not restricted to
affixing. The reinforcing material layer 53F may be formed by plating a reinforcing material on
the surface of the core material 53E. Alternatively, the reinforcing material layer 53F may be
formed by sputtering the reinforcing material on the surface of the core material 53E.
[0056]
Further, as shown in FIG. 3, it is preferable that the upper surface of the magnetic circuit 61 be
disposed on the front side of the diaphragm 53 than the rear surface of the thick portion 53B.
That is, it is preferable that a part of the magnetic circuit is in the recess 53A. The loudspeaker
51 can be made thinner by this configuration.
[0057]
Here, it is preferable that the magnetic circuit 61 be an internal magnet type. By this
configuration, the area of the thin portion 53C 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. 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 bottom plate 64, and the
yoke 65 are made of a magnetic material. These are made of, for example, a hot-rolled steel plate
(SPHC, SPHD, etc.).
[0058]
In the magnetic circuit 61, the top plate 63 and the yoke 65 are magnetized by the magnet 62 to
have different polarities. 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. 4, a
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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.
[0059]
Preferably, a tapered portion 65A is formed on the side surface of the outer periphery of the
yoke 65. That is, the yoke 65 preferably has a shape that tapers 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
shape of the tapered portion 65A is not limited to a linear shape, and may be a curved surface
such as an arc or a stepped shape. Also, the tapered portion 65A may be formed by combining
these as appropriate.
[0060]
The inclined surface 53D of the recess 53A is preferably formed to face the tapered portion 65A.
With this configuration, a distance is secured between the tapered portion 65A and the inclined
surface 53D that allows the diaphragm 53 to be displaced in the axial direction of the voice coil.
In other words, it is possible to secure a distance 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.
[0061]
Further, since the region where the inclined surface 53D is formed is thicker than the thin
portion 53C, the strength of the diaphragm 53 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.
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[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, a 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.
[0065]
FIG. 9 is a rear view of the loudspeaker 51 in the present embodiment. The bottom plate 64
preferably includes an arm portion 91 in addition to the installation portion 64A. The arm
portion 91 extends outward from the installation portion 64A and is coupled to the frame 52.
With this configuration, the magnetic circuit 61 is coupled to the frame 52 through the arm
portion 91.
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[0066]
The bottom plate 64 preferably has a plurality of arm portions 91. FIG. 9 shows four arm
portions 91A to 91D. The arm portion 91 is formed of arm portions 91A to 91D extending in
four directions orthogonal to each other. Further, 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。 Leakage of the magnetic flux of the magnetic circuit 61 to the
arm portion 91 can also be suppressed. Therefore, the magnetic flux density in the magnetic gap
56 can be increased.
[0067]
It is preferable that the installation portion 64A and the arm portion 91 be integrally formed. In
this configuration, the bottom plate 64 can be inexpensively manufactured because there is no
need for a separate member for fixing the magnetic circuit 61 to the frame 52. Also, the bottom
plate 64 can be made thinner. 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 is preferably made of a magnetic material, and the arm portion
91 is preferably 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.
[0068]
The loudspeaker 51 is not limited to the inner magnet type magnetic circuit 61, and may be an
outer magnet type or a combination of an inner magnet type and an outer magnet type. FIG. 10
is a cross-sectional view of another loudspeaker 351 in the present embodiment. In the
loudspeaker 351, about the same composition as the loudspeaker 51, the same numerals are
attached and the explanation is omitted. In FIG. 10, the inner part of the magnetic circuit 81 is
constituted by the center pole 84 B, and the outer part of the magnetic circuit 81 is constituted
by the magnet 82 and the top plate 83.
[0069]
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The loudspeaker 351 has an external magnet type magnetic circuit 81 in place of the internal
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 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.
[0070]
Also in this case, the magnetic circuit 81 is disposed at a position corresponding to the recess
53A. Therefore, the loudspeaker 51 can be thinned by using the external magnet type magnetic
circuit 81.
[0071]
Here, it is preferable that a tapered portion 82A be formed on the side surface of the outer
periphery of the top plate 83. And it is preferable that the taper part 82A and the inclined
surface 53D of the recessed part 53A be disposed to face 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 82A is formed also in the side surface of the
outer periphery of the magnet 82. As shown in FIG. It is preferable that the tapered portion 82A
and the inclined surface 53D be disposed to face each other.
[0072]
The magnet 82 may be a neodymium magnet, samarium iron magnet, ferrite magnet or the like.
The cross-sectional shape of the magnet 82 made of these metals may be square. In this case, the
inclined surface 53D may not be provided in the recess 53A.
10-05-2019
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[0073]
FIG. 11 is a cross-sectional view of still another loudspeaker 451 in the present embodiment. In
the loudspeaker 451, about the structure similar to the loudspeakers 51 and 351, the same code
| symbol is attached | subjected and the description is abbreviate | omitted. In FIG. 11, the inner
part of the magnetic circuit 86 is composed of the magnet 62 (first magnet) and the top plate 63
(first top plate), and the outer part of the magnetic circuit 86 is the magnet 82 (first 2) and a top
plate 83 (second top plate).
[0074]
The loudspeaker 451 has a magnetic circuit 86 in which inner and outer magnets are combined.
The magnetic circuit 86 has a magnet 62 (first magnet) and a top plate 63 (first top plate) in
place of the center pole 84B of the magnetic circuit 81 in FIG. The top plate 63 is mounted on
the top surface of the magnet 62. The magnet 62 and the magnet 82 (second magnet) are
mounted on the bottom plate 84 so as to be magnetically connected in series. A magnetic gap 56
is formed between the side surface of the outer periphery of the top plate 63 and the side surface
of the inner periphery of the top plate 83 (second top plate). Also in this configuration, it is
preferable that a tapered portion 82A be formed on the side surface of the outer periphery of the
top plate 83. Further, it is preferable that the tapered portion 82A and the inclined surface 53D
of the concave portion 53A be disposed to face each other. With this configuration, even if the
thickness of the magnet 62 and the magnet 82 is reduced, the magnetic flux density in the
magnetic gap 56 can be set to a desired value or more. Therefore, the loudspeaker 51 can be
thinned. Also, the sound pressure of the loudspeaker 51 can be improved.
[0075]
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, 351, and 451 are denoted by the
same reference numerals, and the description thereof will be 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.
10-05-2019
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[0076]
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.
[0077]
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, for example,
screwing. 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.
[0078]
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 can also function 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, magnetic
saturation in the magnetic circuit 161 is suppressed. As a result, the magnetic flux density of the
magnetic gap 56 can be increased.
[0079]
The pedestal 152 has an arm portion 153 extending in the outer circumferential direction from
the mounting portion 152A. The outer end 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
10-05-2019
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nonmagnetic material. This configuration can suppress the magnetic flux of the magnetic circuit
161 from leaking to the arm portion 153 side.
[0080]
In addition, a fixing claw such as a protrusion may be provided at the outer end of the arm
portion 153. In this case, it is preferable to provide the frame 52 with a groove or a notch. Then,
the pedestal 152 may be fixed to the frame 52 by fitting the fixing claw into a groove or a notch.
[0081]
Here, 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 153A to
153F radially extending in the outer peripheral direction from the mounting portion 152A 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.
[0082]
Further, it is preferable that an opening 192 be formed between the adjacent arm portions 153A
to 153F. 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
192. また。 Leakage of the magnetic flux of the magnetic circuit 161 to the arm portions 153A
to 153F can also be suppressed. Therefore, the magnetic flux density in the magnetic gap 56 can
be increased.
[0083]
As described above, in the loudspeaker of the present disclosure, the outer peripheral portion of
the diaphragm has a thick portion thicker than the inner peripheral portion. Therefore, the
strength of the diaphragm can be sufficiently secured. In addition, the diaphragm has a thin
portion thinner than the thick portion at the center of the rear surface. The magnetic circuit is
disposed at a position corresponding to the thin portion. This configuration can reduce the
10-05-2019
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distance between the front surface of the diaphragm and the top surface of the magnetic circuit.
Therefore, the loudspeaker can be thinned while securing the magnetic flux density in the
magnetic gap. The result is a thin loudspeaker with low distortion at high sound pressure levels.
[0084]
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, the loudspeaker 351, or the loudspeaker 451 of the
present embodiment. Although FIG. 14 shows a car as an example, the mobile device 201 is not
limited to a car, but may be a ship, an aircraft, a train, a motorcycle or the like.
[0085]
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.
[0086]
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. In
addition, the place which installs the loudspeaker 500 is not restricted above, A dashboard, a rear
tray (not shown), etc. may be sufficient.
10-05-2019
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[0087]
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.
[0088]
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 should not be interpreted in
a limited manner.
[0089]
The present invention can be changed and improved without departing from the gist thereof, and
the present invention also includes the equivalents thereof.
[0090]
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 household audio devices.
[0091]
51, 151, 351, 451,500 Loudspeaker 52 Frame 52A Base 52B Mounting portion 52C Attached
portion 53 Diaphragm 53A Recess 53B Thick portion 53C Thin portion 53D Slope surface 53E
Core 53F Reinforcement layer 54 Edge 54A 54B Second Edge 55 Voice Coil Body 55A Bobbin
55B Voice Coil 56 Magnetic Gap 57 Terminal 57A Positive Terminal 57B Negative Terminal 58
Connection Wire 61 Magnetic Circuit 62 Magnet 63 Top Plate 64 Bottom Plate 64A Installation
Part 65 Yoke 65A Tapered Part 71 Roll Part 71A First roll portion 71B Second roll portion 72
Joint portion 72A First joint portion 72B Second joint portion 72C Third joint portion 72D
Fourth joint portion 81 Magnetic circuit 82 Magnet 82A Tapered portion 83 Top plate 84
Bottom plate 84 A setting portion 84B center pole 86 magnetic circuit 91 arm portion 91A arm
portion 91B arm portion 91C arm portion 91D arm portion 92, 192 opening 152 pedestal 152A
mounting portion 153 arm portion 153A arm portion 153B arm portion 153C arm portion 153D
arm portion 153E arm Part 153F Arm part 153G Arm part 161 Magnetic circuit 164 Bottom
plate 201 Moving body device 202 Main body part 202A Ride space 202B Exterior part 202C
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Interior part 202D Roof 202E Door 203 Drive part 211 Amplification part 300 Hollow part 400
Inner part 450 Outer part
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