JPWO2016111005

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DESCRIPTION JPWO2016111005
Abstract In a speaker device, the reproduction sound pressure is increased, and the heat
resistance and the water resistance are improved. The speaker device (1) includes a diaphragm
(10) made of a film containing polyimide and a frame (20), and a cross section parallel to the
sound radiation direction passing through the center of the diaphragm (10) is the sound
radiation direction In contrast, a first curved plate (11) having a concave arc, a second curved
plate (12) having a convex arc, and a concave arc sequentially from the inner periphery to the
outer periphery of the diaphragm (10). And the fourth curved plate (14) having a convex arc, and
the area of the first curved plate (11) is the second curved plate (12), the third curved plate It is
characterized in that it is larger than any of the respective areas of the plate (13) and the fourth
curved plate (14).
Speaker device
[0001]
The present invention relates to a speaker device.
[0002]
Hybrid vehicles and electric vehicles are highly silent when traveling, and even when such
vehicles approach pedestrians such as pedestrians, the pedestrians may not notice the approach.
Then, in order to emit a notification sound informing a passerby that a hybrid vehicle or the like
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is approaching, various speaker devices mounted on a hybrid vehicle or the like have been
proposed (for example, see Patent Document 1). The specifications of such a speaker device were
uniquely determined by each manufacturer, and for example, they were not designed based on a
standardized standard regarding heat resistance and environmental resistance.
[0003]
JP, 2004-13683, A
[0004]
By the way, in recent years, there is a trend that the mounting method and specification of the
speaker device for the notification sound are legalized.
In addition, since it is mounted in the vicinity of an engine or motor such as a hybrid vehicle,
such a speaker device is required to have environmental resistance such as reproduction sound
pressure, heat resistance, moisture resistance, water resistance, etc. for each frequency. There is.
[0005]
Therefore, as a problem to be solved by the present invention, in the speaker device, raising the
reproduction sound pressure and improving the heat resistance and the water resistance can be
mentioned as an example.
[0006]
In order to solve the above problems, the invention described in claim 1 includes a diaphragm
made of a film containing polyimide, and a frame for supporting the diaphragm, and the sound
radiation direction passes through the center of the diaphragm. In the cross section parallel to
the sound radiation direction, a first curved plate with a concave arc, a second curved plate with
a convex arc, and a concave second one with a concave arc in this order from the inner periphery
to the outer periphery of the diaphragm A third curved plate having a circular arc and a fourth
curved plate having a convex circular arc, the area of the first curved plate being the second
curved plate, the third curved plate, and the fourth curved plate It is a speaker device
characterized by being larger than either of each area.
[0007]
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It is the perspective view which looked at the speaker apparatus concerning the 1st Example of
this invention from the sound radiation destination.
It is the perspective view which looked at the speaker apparatus shown by FIG. 1 from the back
side with respect to a sound radiation destination.
It is sectional drawing which shows the cross section which followed the sound radiation
direction of the speaker apparatus shown by FIG. FIG. 4 is a perspective view showing the
speaker device shown in FIG. 1 cut so that the cross section shown in FIG. 3 can be seen. FIG. 4 is
a partial cross-sectional view showing a cross section of the diaphragm shown in FIG. 3 for the
right half in the drawing. FIG. 6 is a view schematically showing a cross section of the diaphragm
shown in FIG. 5; It is a graph which shows the frequency characteristic of the reproduction sound
pressure in the speaker apparatus shown by FIG. 1, and impedance. It is a figure which shows the
shape of the cross section which followed the sound radiation direction of the diaphragm
concerning 2nd Example of this invention.
[0008]
Hereinafter, a speaker device according to an embodiment of the present invention will be
described. A speaker device according to an embodiment of the present invention includes: a
diaphragm made of a film containing polyimide; and a frame for supporting the diaphragm, and a
cross section parallel to the sound radiation direction passing through the center of the
diaphragm is A first curved plate having a concave arc, a second curved plate having a convex
arc, and a third curved plate having a concave arc in order from the inner periphery to the outer
periphery of the diaphragm with respect to the sound radiation direction A plate, and a fourth
curved plate having a convex arc, wherein the first curved plate has an area of each of the second
curved plate, the third curved plate, and the fourth curved plate It is characterized by being
larger than either.
[0009]
In the speaker device mounted on the vehicle to emit a notification sound notifying the passerby
of the approach of the vehicle, it is assumed that a high pressure water flow is hit against the
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diaphragm from the outside of the vehicle. Water resistance in terms of strength to withstand
pressure is also required. According to the speaker device of the present embodiment, heat
resistance and water resistance are improved by forming the diaphragm with a film containing
polyimide. Furthermore, each of the curved plates including the first curved plate having the
largest planar view area and the most subjected to the pressure of the water flow includes arcs in
cross sections parallel to the sound radiation direction through the center of the diaphragm. Such
an arc is a structure that is mechanically equivalent in any part. Therefore, the internal pressure
of the diaphragm generated by the pressure of the water around the diaphragm acts evenly on
each portion of the diaphragm, and as a result, the force can be dispersed. It is excellent in water
resistance in terms of strength obtained. Specifically, a portion of the first curved plate, the
second curved plate, the third curved plate, and the fourth curved plate is not easily deformed by
a predetermined pressure of the water flow, and returns to a predetermined shape even if
temporarily deformed. What can be done is an example.
[0010]
Here, in the diaphragm, the shape of the cross section of the first curved plate, which plays a role
of sound radiation, has an arc whose cross section parallel to the sound radiation direction is
concave with respect to the sound radiation direction. High frequency vibration is difficult to be
transmitted to the first curved plate and high frequency sound is hard to be emitted. However, it
is mainly low frequency sound that is often required as the above notification sound. Further, in
the present embodiment, the above-described shape of the first curved plate is excellent in water
resistance in terms of strength. Further, in the diaphragm, the second, third, and fourth curved
plates have arc-shaped cross sections as described above which are located on the outer
peripheral side of the first curved plate and which also have an edge role. Is excellent in water
resistance in terms of strength.
[0011]
Thus, the heat resistance and the water resistance are improved in the speaker device according
to the present embodiment.
[0012]
In the speaker device according to the embodiment of the present invention, the radius of
curvature of the arc of the first curved plate is larger than the radius of curvature of the arc of
the third curved plate, and the radius of curvature of the arc of the fourth curved plate Is smaller
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than the radius of curvature of the arc of the second curved plate.
That is, in this speaker device, the radius of curvature of the arc of the first curved plate that
plays the role of sound emission is larger than the radius of curvature of the circular arc of the
third curved plate that also plays the role of the edge. Furthermore, the radius of curvature of the
arc of the second curved plate is smaller than the radius of curvature of the arc of the third
curved plate. In the diaphragm of this speaker device, the curvature radius of the arc of the
second curved plate near the first curved plate and located near the inner periphery of the edge
is the curvature of the arc of the third curved plate located near the widthwise center of the edge
It is smaller than the radius.
[0013]
This allows the lowest resonance frequency to be close to the desired frequency, for example 300
Hz. Further, the reverse resonance frequency can be set to, for example, 5 kHz or more, and a
large dip can be prevented from appearing in the frequency band of 5 kHz or less.
[0014]
Further, in the speaker device according to the embodiment of the present invention described
above, the diaphragm includes the second curved plate having a convex arc cross section, the
third curved plate having a concave circular arc cross section, and the convex And the fourth
curved plate having a cross section of a circular arc. The shapes of the cross sections parallel to
the sound radiation direction passing through the centers of the diaphragms of the second
curved plate, the third curved plate, and the fourth curved plate are all arcs. Such an arc is a
structure that is mechanically equivalent in any part. Therefore, the force inside the diaphragm
caused by the pressure of the water around the diaphragm acts evenly on each portion of the
diaphragm, and as a result, the force can be dispersed. That is, according to the above-mentioned
speaker device, it is possible to further improve the water resistance in terms of strength that can
withstand the pressure of such water flow. Specifically, a part of the second curved plate, the
third curved plate, and the fourth curved plate is hardly deformed by a predetermined pressure,
and can be restored to a predetermined shape even if temporarily deformed. .
[0015]
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In the above-described speaker device according to the embodiment of the present invention, an
opening is provided at a central portion of the first curved plate, the opening is covered by a cap,
and the cap is a center of the diaphragm. And a cross section parallel to the sound radiation
direction is a concave arc with respect to the sound radiation direction. Such an arc is a structure
that is mechanically equivalent in any part. Therefore, the force inside the cap generated by the
pressure of the water around the cap acts evenly on each portion of the cap, and as a result, the
force can be dispersed. That is, according to the above-mentioned speaker device, it is possible to
further improve the water resistance in terms of strength that can withstand the pressure of such
water flow. Specifically, a portion of the cap is not easily deformed by a predetermined pressure
of the water flow, and can be restored to a predetermined shape even if temporarily deformed.
[0016]
Further, in the speaker device provided with a cap whose cross section is a circular arc, the cap is
made of a film containing polyimide. Thereby, the heat resistance and the water resistance of the
cap can be further improved.
[0017]
Further, in the speaker device provided with a cap having an arc cross section, the radius of
curvature of the arc of the cap is smaller than the radius of curvature of the arc of the first
curved plate. Caps of smaller radius of curvature have higher mechanical strength.
[0018]
Further, in the speaker device according to the embodiment of the present invention described
above, the diaphragm has any one of 50 μm, 75 μm, 100 μm, and 125 μm. The generalpurpose product of a polyimide film has a film thickness of 50 μm, 75 μm, 100 μm, 125 μm
or the like. By setting the thickness of the diaphragm to the above thickness, a general-purpose
polyimide film can be used as it is, so that the manufacturing cost of the speaker device can be
suppressed.
[0019]
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In the speaker device according to the embodiment of the present invention, the diaphragm has a
thickness of 125 μm. By setting the thickness of the diaphragm to such a thickness, it is possible
to maintain the heat resistance and the water resistance on a higher strength side while reducing
the manufacturing cost of the speaker device, and to reduce the weight of the diaphragm.
[0020]
Further, in the above-described speaker device according to the embodiment of the present
invention, the diaphragm is disposed in a vehicle, and generates a notification sound that
announces the approach of the vehicle toward the outside of the vehicle. The speaker device for
such notification sound requires high reproduction sound pressure and high heat resistance and
water resistance. This speaker device has the above-mentioned high reproduction sound
pressure, high heat resistance and water resistance.
[0021]
(First Embodiment) A speaker apparatus according to a first embodiment of the present invention
will be described with reference to the drawings. FIG. 1 is a perspective view of a speaker
apparatus according to a first embodiment of the present invention as viewed from a sound
emission destination. FIG. 2 is a perspective view of the speaker device shown in FIG. 1 as viewed
from the rear side with respect to the sound emission destination. FIG. 3 is a cross-sectional view
showing a cross section along the sound radiation direction of the speaker device shown in FIG.
FIG. 4 is a perspective view showing the speaker device shown in FIG. 1 cut so that the cross
section shown in FIG. 3 can be seen.
[0022]
The speaker device 1 of the present embodiment is mounted on a vehicle having high quietness
during traveling, such as a hybrid vehicle or an electric vehicle, for example, and emits a
notification sound notifying a passerby that the vehicle is approaching.
[0023]
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The speaker device 1 includes a diaphragm 10, a frame 20, a damper 30, a voice coil 40, a
magnetic circuit 50, and a cap 60.
The diaphragm 10 is a diaphragm whose outer peripheral shape is circular, and an opening 10 a
is formed at the center thereof. The vicinity of the outer peripheral edge 10b of the diaphragm
10 is connected and supported by the cylindrical frame 20, and the vicinity of the inner
peripheral edge of the opening 10a in the diaphragm 10 is connected and supported by the
peripheral surface near the upper edge of the cylindrical voice coil bobbin 41. ing. The upper
edge of the voice coil bobbin 41 slightly protrudes from the opening 10 a in the sound radiation
direction, and the opening 10 a is covered by a cap 60 placed on the upper edge of the voice coil
bobbin 41.
[0024]
The damper 30 is a flexible annular member, and the outer peripheral edge is connected to and
supported by the frame 20, and the inner peripheral edge is connected to and supported by the
circumferential surface of the voice coil bobbin 41. The voice coil 40 is formed on the
circumferential surface of the voice coil bobbin 41, and is disposed in the magnetic gap 51 in the
magnetic circuit 50. Further, the voice coil 40 is connected to the external wiring 44 via the
internal wiring 42 and the wiring terminal 43. The wiring terminal 43 is fixed to the outer
surface of the frame 20. One end of the internal wiring 42 is connected to the voice coil 40 and
wired inside the frame 20, and the other end is connected to the wiring terminal 43 through the
opening 20 a of the frame 20. Then, one end of the external wiring 44 is connected to the wiring
terminal 43.
[0025]
When an acoustic signal is supplied to the voice coil 40 through the external wiring 44 and the
internal wiring 42, the voice coil 40 is vibrated by the Lorentz force acting from the magnetic
circuit 50, and the vibration is transmitted to the diaphragm 10 and the diaphragm 10 Emits a
sound.
[0026]
Here, in the present embodiment, the diaphragm 10 has the following shape.
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FIG. 5 is a partial cross-sectional view showing the cross section of the diaphragm shown in FIG.
3 for the right half in the figure, and FIG. 6 schematically shows the cross section of the
diaphragm shown in FIG. FIG.
[0027]
The diaphragm 10 includes a first curved plate 11, a second curved plate 12, a third curved plate
13, and a fourth curved plate 14.
[0028]
The first curved plate 11 is located at the center of the diaphragm 10, and the cross section
parallel to the sound radiation direction has a concave arc with respect to the sound radiation
direction.
The first curved plate 11 has a ring shape having an opening 10 a at the center when viewed
from the sound radiation direction.
[0029]
In the present embodiment, the arc shape in the cross section of the first curved plate 11 is
generally in the shape of a bowl where the arc shown only in the right half in FIG. 5 is connected
to the left half (not shown). However, the arc shape of the cross section of the first curved plate
according to the present invention is not limited to such a bowl-shaped arc shape. The arc shape
of the cross section of the first curved plate according to the present invention is, for example, a
cross section as a whole including two arcs if the cross section of one side portion from the
center to the outer periphery of the first curved plate is arc shaped. It may be W-shaped.
[0030]
The second curved plate 12 is located on the outer peripheral side of the first curved plate 11,
and a cross section parallel to the sound radiation direction has a convex arc with respect to the
sound radiation direction. The second curved plate 12 has a ring shape when viewed from the
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sound radiation direction. The third curved plate 13 is located on the outer peripheral side of the
second curved plate 12, and a cross section parallel to the sound radiation direction has a
concave arc with respect to the sound radiation direction. The third curved plate 13 has a ring
shape when viewed from the sound radiation direction. The fourth curved plate 14 is located
between the outer peripheral side of the third curved plate 13 and the outer peripheral edge 10b
of the diaphragm 10, and a cross section parallel to the sound radiation direction has a convex
arc with respect to the sound radiation direction. Have. The fourth curved plate 14 has a ring
shape when viewed from the sound radiation direction. The first curved plate 11 is larger in plan
view area than any of the second curved plate 12, the third curved plate 13, and the fourth
curved plate 14 when viewed in the sound radiation direction. In the diaphragm 10, the first
curved plate 11 mainly plays a role of sound radiation and is positioned on the outer peripheral
side of the first curved plate 11, and the second curved plate 12, the third curved plate 13, and
the fourth curved plate 14 The portion 19 having the function mainly plays the role of an edge.
[0031]
Furthermore, in the present embodiment, the outer peripheral edge of the first curved plate 11
and the inner peripheral edge of the second curved plate 12 are connected by the first inclined
portion 15 whose cross section parallel to the sound radiation direction is a straight line. The
outer peripheral edge of the second curved plate 12 and the inner peripheral edge of the third
curved plate 13 are connected by a second inclined portion 16 whose cross section parallel to
the sound radiation direction is a straight line. The outer peripheral edge of the third curved
plate 13 and the inner peripheral edge of the fourth curved plate 14 are connected by a third
inclined portion 17 whose cross section parallel to the sound radiation direction is a straight line.
Further, from the outer peripheral edge of the fourth curved plate 14 to the outer peripheral
edge 10 b of the diaphragm 10 is a flat ring portion 18 which is a straight line substantially
orthogonal to the sound radiation direction. The flat ring portion 18 is overlapped and attached
to the upper surface of the frame 20, whereby the diaphragm 10 is connected to and supported
by the frame 20 in the vicinity of the outer peripheral edge 10b. The flat ring portion 18 is an
attachment margin for the frame 20.
[0032]
In the speaker device 1 of the present embodiment mounted on a vehicle to emit a notification
sound notifying the passing of a vehicle approaching, it is assumed that a high pressure water
stream strikes the diaphragm from the outside of the vehicle. Water resistance is also required in
terms of strength that can withstand such water flow pressure. According to the speaker device 1
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of the present embodiment, the heat resistance and the water resistance are improved by
forming the diaphragm 10 with a film containing polyimide. Furthermore, in each of the curved
plates 11 to 14 including the first curved plate 11 having the largest planar view area and the
most subjected to the pressure of the water flow, the cross sections parallel to the sound
radiation direction are all arcs. Such an arc is a structure that is mechanically equivalent in any
part. Therefore, the force inside the diaphragm caused by the pressure of the water around the
diaphragm acts evenly on each portion of the diaphragm, and as a result, the force can be
dispersed. In the speaker device 1 of the present embodiment, this improves the water resistance
in terms of strength that can withstand the pressure of the water flow as described above.
Specifically, a portion of the cap is not easily deformed by a predetermined pressure of the water
flow, and can be restored to a predetermined shape even if temporarily deformed.
[0033]
Here, in the diaphragm 10, since the shape of the cross section of the first curved plate 11, which
plays a role of sound radiation, has a circular arc whose cross section parallel to the sound
radiation direction is concave with respect to the sound radiation direction, High frequency
vibration of the coil is difficult to be transmitted to the first curved plate 11, and high frequency
noise is hard to be emitted. However, what is often required as the above notification sound is
mainly low frequency sound of 5 KHz or less, for example, and in the present embodiment, the
above-described shape of the first curved plate 11 makes water resistance in terms of strength It
is excellent in sex. Further, in the diaphragm 10, the sections of the second curved plate 12, the
third curved plate 13 and the fourth curved plate 14 which the portion 19 located on the outer
peripheral side of the first curved plate 11 also plays a role of edge has It is excellent in water
resistance in terms of strength by having such a circular arc.
[0034]
FIG. 7 is a graph showing frequency characteristics of reproduced sound pressure and
impedance in the speaker device shown in FIG. In graph G1 of FIG. 7, frequency [Hz] is taken
along the horizontal axis, reproduction sound pressure [dB] is taken along the left vertical axis,
and impedance [ohm] is taken along the right vertical axis. ing. And, on this graph G1, a sound
pressure curve L1 representing the frequency characteristic of the reproduction sound pressure
and an impedance curve L2 representing the frequency characteristic of the impedance are
described. The sound pressure curve L1 measures the sound pressure measured at a sound
collecting point 1 m away from the diaphragm 10 when an acoustic signal of 20 W is supplied to
the speaker device 1 while changing the frequency, and the result is It is obtained by plotting. As
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can be seen from the sound pressure curve L1, in the speaker device 1 of the present
embodiment, the reproduction sound pressure is high for low frequency sound of 5 KHz or less.
[0035]
As described above, in the speaker device 1 of the present embodiment, high reproduction sound
pressure and improvement in heat resistance and water resistance are realized.
[0036]
Here, in the speaker device 1 of the present embodiment, as shown in FIG. 6, the radius of
curvature R11 of the arc of the first curved plate 11 is larger than the radius of curvature R13 of
the arc of the third curved plate 13, The radius of curvature R14 of the arc of the fourth curved
plate 14 is smaller than the radius of curvature R12 of the arc of the second curved plate 12.
That is, in the speaker device 1, the radius of curvature R 11 of the arc of the first curved plate
11 playing the role of sound emission is larger than the radius of curvature R 13 of the arc of the
third curved plate 13 located near the widthwise center of the edge. .
[0037]
Further, the radius of curvature R14 of the arc of the fourth curved plate 14 closest to the frame
20 is smaller than the radius of curvature R12 of the arc of the second curved plate 12. As a
result, in the speaker device 1, the lowest resonance frequency can be made close to a desired
frequency, for example, 300 Hz. Further, the reverse resonance frequency can be set to, for
example, 5 kHz or more, and a large dip can not be generated in the sound pressure frequency
characteristic of the frequency band of 5 kHz or less.
[0038]
As can be seen from the sound pressure curve L1 in the graph G1 of FIG. 7, in the speaker device
1 of the present embodiment, the minimum points P1, P2 and P3 of the reproduction sound
pressure are often required as the above notification sound 5KHz It appears on the high
frequency side more than. As described above, according to the speaker device 1 of the present
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embodiment, the reduction in the reproduction sound pressure of the desired low frequency
sound is suppressed.
[0039]
Further, in the speaker device 1 of the present embodiment, the radius of curvature R12 of the
arc of the second curved plate 12 is smaller than the radius of curvature R13 of the arc of the
third curved plate 13. With this configuration, in the present embodiment, the above-mentioned
reverse resonance frequency (minimum points P1, P2, P3 of the sound pressure in the graph of
FIG. 7) is shifted to the high frequency side.
[0040]
Further, in the speaker device 1 of the present embodiment, the opening 10a is provided at the
central portion of the first curved plate 11, and the opening 10a is formed by the cap 60 as
shown in FIG. 1, FIG. 3 and FIG. It is covered. And as for this cap 60, the section parallel to the
sound radiation direction becomes a concave circular arc shape to the sound radiation direction.
Such an arc shape is a structure that is mechanically uniform in any part. Therefore, the force
inside the cap 60 generated by the pressure of the water around the cap 60 uniformly acts on
each portion of the cap, and as a result, the force can be dispersed. That is, according to the
speaker device 1, the water resistance in terms of strength that can withstand the pressure of the
water flow is further improved. Specifically, a portion of the cap 60 is unlikely to be temporarily
deformed by a predetermined pressure of the water flow, and can be restored to a predetermined
shape even if deformed.
[0041]
Further, in the speaker device 1 of the present embodiment, the cap 60 is also formed of a film
containing polyimide. Thereby, the heat resistance and the water resistance of the cap 60 are
further improved.
[0042]
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Further, in the speaker device 1 of the present embodiment, the radius of curvature R60 (FIG. 3)
of the arc of the cap 60 is smaller than the radius of curvature R11 of the first curved plate 11.
Caps of smaller radius of curvature have higher mechanical strength.
[0043]
Moreover, the diaphragm 10 has a thickness of any one of 50 μm, 75 μm, 100 μm, and 125
μm. The general-purpose product of a polyimide film has a film thickness of 50 μm, 75 μm,
100 μm, 125 μm or the like. By setting the thickness of the diaphragm to the above thickness,
a general-purpose polyimide film can be used as it is, so heat resistance and water resistance are
maintained while suppressing the manufacturing cost of the speaker device, and characteristics
such as minimum resonance frequency Can be optimized.
[0044]
Further, it is more preferable that the diaphragm 10 have a thickness of 125 μm among the
above-mentioned thicknesses. By setting the thickness of the diaphragm 10 to such a thickness, it
is possible to achieve weight reduction while maintaining the reproduction sound pressure, the
heat resistance, and the higher water resistance while suppressing the manufacturing cost of the
speaker device 1.
[0045]
Further, in the present embodiment, the speaker device 1 is mounted on a vehicle having high
quietness during traveling, and is applied to the speaker device for emitting a notification sound
notifying the passing user of the approach of the vehicle. That is, in the speaker device 1 of the
present embodiment, the diaphragm 10 is disposed in the vehicle, and generates a notification
sound that indicates the approach of the vehicle toward the outside of the vehicle. The speaker
device for such notification sound requires high reproduction sound pressure and high heat
resistance and water resistance. The speaker device 1 of the present embodiment has the abovementioned high reproduction sound pressure, high heat resistance and water resistance.
[0046]
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Second Embodiment Next, a speaker apparatus according to a second embodiment of the present
invention will be described. The second embodiment is the same as the first embodiment except
for the shape of the diaphragm. Therefore, in the following, the second embodiment will be
described focusing on the differences from the first embodiment, and the description of the
common points such as the configuration of the speaker device will be omitted.
[0047]
FIG. 8 is a view showing the shape of the cross section parallel to the sound radiation direction of
the diaphragm according to the second embodiment of the present invention. In FIG. 8, the
components equivalent to the components of the diaphragm 10 of the first embodiment shown
in FIG. 6 are shown with the same reference numerals as in FIG. Duplicate descriptions of
elements will be omitted.
[0048]
The second curved plate 12 having a cross-section of a convex circular arc which passes through
the center of the diaphragm 70 and is parallel to the sound radiation direction from the inner
peripheral portion to the outer peripheral portion of the diaphragm 70 in the sound radiation
direction. And the third curved plate 13 having a concave arc cross section, and the fourth
curved plate 14 having a convex arc cross section. The shapes of the cross sections parallel to
the sound radiation direction passing through the centers of the diaphragm 70 of the second
curved plate 12, the third curved plate 13, and the fourth curved plate 14 are all arc shapes.
Such an arc shape is a structure that is mechanically uniform in any part. Therefore, the force
inside the diaphragm 70 generated by the pressure of the water around the diaphragm 70 acts
evenly on each part of the diaphragm 70, and as a result, the force can be dispersed. In the
diaphragm 70, the first curved plate 11 mainly plays a role of sound radiation, and a portion
formed of the second curved plate 12, the third curved plate 13, the fourth curved plate 14 and
the flat ring portion 18 outside thereof. 71 mainly plays the role of edge. Moreover, the
diaphragm 70 of the present embodiment does not have the first inclined portion 15, the second
inclined portion 16, and the third inclined portion 17 shown in FIG. 5 and FIG. 11, the second
curved plate 12, the third curved plate 13, and the fourth curved plate 14 are continuously
connected.
[0049]
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The vibration plate 70 having such a concavo-convex shape further improves the water
resistance in terms of strength that can withstand the pressure of the water flow. Specifically, a
part of the second curved plate 12, the third curved plate 13, and the fourth curved plate 14 is
not easily deformed temporarily by a predetermined pressure of the water flow, and can be
restored to a predetermined shape even if it is deformed. Is an example.
[0050]
The above two examples only show typical forms of the present invention, and the present
invention is not limited to these examples. That is, those skilled in the art can carry out various
modifications without departing from the gist of the present invention in accordance with
conventionally known findings. As long as the configuration of the speaker apparatus of the
present invention is provided even by such a modification, it is of course included in the scope of
the present invention.
[0051]
For example, in each of the first and second embodiments described above, the radius of
curvature R11 of the first curved plate 11 and the radius of curvature R12 of the second curved
plate 12 are examples of the diaphragm according to the present invention. The diaphragms 10
and 70 in which the curvature radius R13 of the curved plate 13 and the curvature radius R14 of
the fourth curved plate 14 have the following magnitude relationship are illustrated. That is, the
radius of curvature R11 of the first curved plate 11 is larger than the radius of curvature R13 of
the third curved plate 13, and the radius of curvature R14 of the fourth curved plate 14 is
smaller than the radius of curvature R12 of the second curved plate 12. Furthermore, the
curvature radius R12 of the second curved plate 12 is smaller than the curvature radius R13 of
the third curved plate 13. However, the diaphragm referred to in the present invention is not
limited to this, and the magnitude relationship of the radius of curvature of the four curved
plates may have a relationship other than the above. However, by the curvature radius in the four
curved plates being in the magnitude relationship as described above, the reverse resonance
frequency in the speaker device can be shifted to the high frequency side to further suppress the
reduction in the reproduction sound pressure of the desired low frequency sound. Is as described
above.
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[0052]
DESCRIPTION OF SYMBOLS 1 Speaker apparatus 10, 70 Diaphragm 10a Opening 10b Outer
peripheral edge 11 1st curved plate 12 2nd curved plate 13 3rd curved plate 14 4th curved
plate 20 Frame 30 Damper 40 Voice coil 50 Magnetic circuit 60 Cap R11 1st curved plate
Radius of curvature R12 radius of curvature of second curved plate R13 radius of curvature of
third curved plate R14 radius of curvature of fourth curved plate
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