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JP2017135655

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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DESCRIPTION JP2017135655
Abstract: To provide a speaker device capable of achieving more faithful reproduction by
suppressing the reaction of a yoke that constitutes a magnetic circuit. A speaker (11) includes a
magnetic circuit (13) having a magnetic gap (18), a voice coil (14) wound around a voice coil
bobbin movably supported in the gap, and one end as a voice coil bobbin and the other end as a
frame. And a diaphragm 15 freely supported. And a damping member 21 having a resonant
frequency different from the resonant frequency of the member constituting the magnetic circuit,
which is fixed to the rear surface portion of the magnetic circuit to suppress reaction of the
magnetic circuit against vibration of the voice coil. . [Selected figure] Figure 1
Speaker device
[0001]
Embodiments of the present invention relate to a speaker device.
[0002]
Heretofore, the vibration of the vibrating body of the speaker unit generates a sound wave and at
the same time an extra vibration is generated, which causes a deterioration in the sound quality
of the speaker device.
Therefore, it is considered to obtain a faithful reproduced sound by forming a visco-elastic body
layer on the frame surface portion of the speaker unit and the inner and outer surfaces
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constituting the speaker cabinet to remove the factor of the sound quality loss.
[0003]
However, although the speaker device converts an electric signal into air vibration by the
magnetic repulsion and attraction of the magnetic circuit and the voice coil, the diaphragm which
is the point of action can not be converted into accurate air vibration by the reaction of the
magnetic circuit. There is a problem called.
[0004]
In addition, since it is necessary to form a visco-elastic layer in a wide area covering the frame
surface portion of the speaker unit and the inner and outer surfaces constituting the speaker
cabinet, there is a problem that the effect is small even though the operation time and material
cost increase .
[0005]
JP 2012-175472 A
[0006]
The problem to be solved by the present invention is to provide a speaker device capable of
achieving more faithful reproduction by suppressing the reaction of the yokes constituting the
magnetic circuit.
[0007]
The speaker device according to the embodiment includes a magnetic circuit having a magnetic
gap, a voice coil wound around a voice coil bobbin movably supported in the gap, one end
around the voice coil bobbin, and the other end around the frame. A speaker device comprising: a
supported diaphragm; and a member constituting the magnetic circuit which is fixed to the rear
surface of the magnetic circuit and suppresses reaction of the magnetic circuit against vibration
of the voice coil. And a damping member having a resonance frequency different from the
resonance frequency.
[0008]
Further, in the speaker device according to the embodiment, a yoke having a center pole
integrally provided at a central portion of a ring-shaped bottom plate, a ring-shaped magnet
surrounding the center pole, and a ring shape surrounding the center pole A magnetic circuit
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comprising: a top plate having a central opening circumferential surface that sandwiches and
fixes the magnet with the bottom plate and forms a magnetic gap with the upper end side outer
circumferential surface of the center pole; A speaker device comprising: a voice coil wound
around a voice coil bobbin movably supported in the magnetic gap; and a diaphragm having one
end supported by the voice coil bobbin and the other end supported by a frame in a freely
vibrating manner. The bottom plate opposite to the surface on which the center pole is formed
has a reaction to the vibration of the diaphragm of the magnetic circuit. A damping member
having a different resonance frequency and the resonance frequency of the member constituting
the magnetic circuit for obtaining, with a.
[0009]
Furthermore, in the speaker device according to the embodiment, a yoke having a center pole
integrally provided at a central portion of a ring-shaped bottom plate, a ring magnet surrounding
the center pole, and a ring shape surrounding the center pole A magnetic circuit comprising: a
top plate having a central opening circumferential surface that sandwiches and fixes the magnet
with the bottom plate and forms a magnetic gap with the upper end side outer circumferential
surface of the center pole; A voice coil wound around a voice coil bobbin movably supported in
the magnetic gap, a diaphragm having one end supported on the voice coil bobbin and the other
end vibrationally supported on a frame, and a back surface portion of the magnetic circuit A
speaker device comprising an annular cancel magnet, wherein the magnetism is generated from
within the annular ring of the cancel magnet. The rear surface portion of the circuit, was fixed
through a vibration damping member, wherein with a resonant frequency different from the
resonance frequencies of the members constituting the magnetic circuit for suppressing the
reaction to the vibration of the vibrating plate of the magnetic circuit.
[0010]
Furthermore, in the speaker device according to the embodiment, a yoke having a center pole
integrally provided in a central portion of a ring-shaped bottom plate, a ring-shaped magnet
surrounding the center pole, and a ring surrounding the center pole A magnetic circuit
comprising: a top plate having a central opening circumferential surface that sandwiches and
fixes the magnet with the bottom plate and forms a magnetic gap with the upper end side outer
circumferential surface of the center pole; A speaker device comprising: a voice coil wound
around a voice coil bobbin movably supported in the magnetic gap; and a diaphragm having one
end supported by the voice coil bobbin and the other end supported by a frame so as to vibrate.
An annular cancel magnet fixed to the rear surface of the magnetic circuit and a rear surface of
the cancel magnet A shield cover for performing magnetic shielding of the cancel magnet, and a
resonance frequency different from a resonance frequency of a member of the magnetic circuit,
which is fixed to the shield cover to suppress reaction of the magnetic circuit to the vibration of
the diaphragm And a damping member provided.
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[0011]
It is a sectional view showing Embodiment 1 of a speaker apparatus.
1 is an exploded perspective view of the main part of FIG.
It is a figure for demonstrating the resonant frequency of the member which comprises a
magnetic circuit.
It is a figure which shows an input signal.
It is a figure for demonstrating the sound pressure level at the time of 21.5 Hz of input signals.
It is a figure for demonstrating the sound pressure level at the time of input signal 172 Hz.
It is a figure for demonstrating the sound pressure level at the time of input signal 1.09 kHz.
It is a figure for demonstrating the sound pressure level at the time of 2.19 kHz of input signals.
It is a figure for demonstrating the sound pressure level at the time of input signal 4.38 kHz. It is
a figure for demonstrating the sound pressure level at the time of 17.5 kHz of input signals. It is
sectional drawing which shows Embodiment 2 of a speaker apparatus. It is sectional drawing
which shows Embodiment 3 of a speaker apparatus. It is sectional drawing which shows
Embodiment 4 of a speaker apparatus. It is sectional drawing which shows Embodiment 5 of a
speaker apparatus. It is sectional drawing which shows Embodiment 6 of a speaker apparatus.
[0012]
Hereinafter, embodiments will be described in detail with reference to the drawings.
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[0013]
(First Embodiment) FIG. 1 is a view showing a first embodiment of a speaker device, and FIG. 2 is
a perspective view showing an essential part of FIG. 1 in an exploded manner.
[0014]
As shown in FIG. 1, the speaker 11 includes a frame 12, a magnetic circuit 13, a voice coil 14, a
diaphragm 15, a damper 16, an edge 17, and a voice coil bobbin 19.
FIG. 1 shows a state in which the diaphragm 15 is directed upward.
[0015]
The frame 12 is a support member for the entire speaker 11.
The magnetic circuit 13 is disposed below the frame 12 in the figure. The voice coil 14 is wound
around a voice coil bobbin 19 and vibrates in the vertical direction in the drawing. The
diaphragm 15 vibrates with the operation of the voice coil 14. The damper 16 serves as a
support for supporting the voice coil 14 on the frame 12. The edge 17 holds the diaphragm 15
to the frame.
[0016]
The frame 12 has, for example, a substantially frusto-conical shape whose upper end is open, and
an opening is formed at the lower radial center where the diameter becomes smaller. The frame
12 is provided with a lower horizontal portion 121 which narrows horizontally inward in the
radial direction near the lower end portion thereof. The frame 12 is provided at its upper end
with an upper horizontal portion 122 opened horizontally outward in the radial direction. The
lower horizontal portion 121 and the upper horizontal portion 122 are formed over the entire
circumference.
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[0017]
The magnetic circuit 13 includes a yoke 131, a magnet 132, and a top plate 133. The yoke 131
is a base member of the magnetic circuit 13 made of a magnetic material, and is fixed to the rear
surface of the magnet 132.
[0018]
The yoke 131 is configured by integrally forming a disk-shaped bottom plate 131 a and a center
pole 131 b which is projected forward from the central portion of the bottom plate 131 a. The
center pole 131 b is formed, for example, in a cylindrical shape. In the yoke 131, the front
surface of the bottom plate 131a is fixed to the rear surface of the donut-like magnet 132.
[0019]
The top plate 133, the magnet 132, and the yoke 131 are coupled in a state where the central
axes coincide with each other. The yoke 131 is disposed, for example, in a state in which the
front end portion of the center pole 131 b slightly protrudes forward from the top plate 133. A
space between the top plate 133 and the center pole 131 b is formed as a magnetic gap 18.
[0020]
The voice coil bobbin 19 is supported by the center pole 131b of the yoke 131 so as to be
movable in the axial direction of the center pole 131b. The voice coil bobbin 19 is formed in a
cylindrical shape, and the voice coil 14 is wound around the outer peripheral surface on the rear
end side of the voice coil bobbin 19. The voice coil 14 is at least partially disposed in the
magnetic gap 18 without contact. By arranging the voice coil 14 in the magnetic gap 18, the top
plate 133, the magnet 132, the yoke 131, and the voice coil 14 constitute a magnetic circuit 13.
[0021]
The diaphragm 15 is formed of, for example, a cone paper material in a truncated cone shape,
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and the diaphragm 15 vibrates and is emitted as a sound. The diaphragm 15 is opened at its
center, and provided with an opposing wall 15a extending rearward over the entire periphery at
the open opening edge. Then, the opposing wall 15 a is brought into contact with the side wall of
the voice coil bobbin 19 and the adhesive is dropped, whereby the inner peripheral portion of
the diaphragm 15 is adhered and fixed to the voice coil bobbin 19. The front outer peripheral
end 15 b side of the diaphragm 15 is adhesively fixed to the inner peripheral end 17 a of the
edge 17. The edge 17 has a ring-like form, and its cross section is formed in a bowed bending
state. The outer peripheral end 17 b of the edge 17 is bonded and fixed to the upper horizontal
portion 122 of the frame 12, whereby the diaphragm 15 is supported by the frame 12.
[0022]
Further, a center cap 20 is disposed above the voice coil bobbin 19. The center cap 20 has a
substantially dome shape, and is disposed inside the diaphragm 15 so as to cover the voice coil
bobbin 19. The center cap 20 serves to prevent dust from entering the inside of the voice coil 14
and the diaphragm 15.
[0023]
The damper 16 is a corrugation damper having a substantially ring shape which is concentrically
press-formed, and is interposed between the voice coil 14 and the frame 12 over the entire
circumference. Specifically, the inner peripheral portion of the damper 16 is fixed to a
substantially central portion in the vertical direction on the outer peripheral surface of the voice
coil bobbin 19, and the outer peripheral portion of the damper 16 is adhesively fixed to the lower
horizontal portion 121 of the frame 12.
[0024]
A damping member 21 is fixed to a rear surface portion which is an opposite surface of the
bottom plate 131a to which the magnet 132 is coupled. The damping member 21 is composed
of, for example, an elastic body 21 a made of butyl rubber and a damping plate 21 b made of, for
example, brass. The damping plate 21b is fixed to the bottom plate 131a via the elastic body 21a
by being tightened using a screw 23 as a fixing means via the screw hole 22.
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[0025]
As the elastic body 21a, butyl rubber was mentioned as an example, but silicon rubber etc. can be
considered otherwise. The damping plate 21 b is exemplified by metal brass, but may be stainless
steel or the like. The point is that any material may be used as long as it has a damping function
to suppress the vibration of the yoke 131, and it may be a nonmetal such as a ceramic plate.
[0026]
Here, the yoke 131 has a resonance frequency f1, the elastic body 21a has a resonance
frequency f2, and the damping plate 21b has a resonance frequency f3. Consider the case where
the relationship between the resonance frequencies f1 to f3 is f1> f2 <f3.
[0027]
FIG. 3 is a view schematically showing the relationship between the Q value (resonance point) of
each of the yoke 131, the elastic body 21a and the damping plate 21b and the resonance
frequency.
[0028]
In FIG. 3, the Q value of the resonance frequency f1 of the yoke 131 is Q (f1), the Q value of the
resonance frequency f2 of the elastic body 21a is Q (f2), and the Q value of the resonance
frequency f3 of the damping plate 21b is Q (f3 And the Q value of these resonant frequencies f1f3 and the Q value obtained by combining Q (f1) -Q (f3) are shown as Q (f4).
[0029]
The diaphragm 15 in a state without the damping member 21 is driven by the magnetic circuit
13 of the resonance frequency f1 of the yoke 131.
Therefore, when the input signal in the band of the resonance frequency f1 is supplied to the
voice coil 14, the yoke 131 makes a reaction of the voice coil 14.
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This reaction causes the yoke 131 to absorb the movement of the voice coil 14. This is
considered to be a factor that impairs the sound quality.
[0030]
On the other hand, the case where the input signal is supplied to the magnetic circuit 13 when
the damping member 21 is fixed to the yoke 131 will be considered. The respective resonance
frequencies f1 to f3 of the members of the yoke 131, the elastic body 21a, and the damping plate
21b in this case can eliminate the occurrence of a specific resonance frequency band as indicated
by Q (f4) in FIG.
[0031]
As described above, damping members 21 having a resonance frequency different from that of
the yoke 131 are overlapped and fixed, and the resonance frequency f1 of the yoke 131 is set to
the state of f4 having no resonance frequency band. As a result, the vibration of the resonance
frequency f1 of the yoke 131 is suppressed, and the diaphragm 15 can realize a faithful
movement based on the input signal.
[0032]
With reference to FIG. 4, FIG. 5A-FIG. 5 F, the acoustic characteristic effect of Embodiment 1 and
the comparative example by the magnetic circuit 13 with and without the damping member 21 is
contrasted and demonstrated.
[0033]
FIG. 4 shows an example of a rectangular wave input signal supplied to the voice coil 14 of the
magnetic circuit 13.
The vertical axis of the input signal indicates the sound pressure level, and the horizontal axis
indicates the angle.
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[0034]
5A at an input signal of 21.5 Hz, FIG. 5B at an input signal of 172 Hz, FIG. 5C at an input signal
of 1.09 kHz, FIG. 5D at an input signal of 2.19 kHz, and FIG. 5E at an input signal of 4.38 kHz,
FIG. These are figures for demonstrating each sound pressure level in 17.5 kHz of time of input
signal. In addition, the broken line of FIG. 5A-FIG. 5 F shows the case where there is no damping
member 21, and the continuous line shows the case where the damping member 21 is installed.
[0035]
The measurement results of FIGS. 5A to 5F are obtained by using a microphone to obtain a sound
pressure level in which the diaphragm 15 is placed at a distance of 250 cm from the external
magnet type speaker of 7 cmφ and the speaker. Further, as the elastic body 21 a of the damping
member 21, butyl rubber having a thickness of 1 mm was used. As the damping plate 21b of the
damping member 21, a brass having a thickness of 10 mm and a diameter larger than that of the
center pole 131b affecting the vibration of the bottom plate 131a was used. The yoke 131 uses,
for example, a material having an inherent resonant frequency f1 near 2 kHz.
[0036]
And the sound pressure level of each frequency at the time of an input signal 21.5 Hz, 172 Hz,
1.09 kHz, 2.19 kHz, 4.38 kHz, and 17.5 kHz was measured.
[0037]
As a result of the measurement, the sound pressure level at the input signal 21.5 Hz does not
show a substantial difference without the damping member 21.
Similarly, the sound pressure level at an input signal of 17.5 kHz does not show a substantial
difference without the damping member 21.
[0038]
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On the other hand, the sound pressure level of the input signal of 1.09 kHz shown in FIG. 5C,
2.19 kHz shown in FIG. 5D, and 4.38 kHz shown in FIG. In FIGS. 5C-5E, as shown in (a)-(c) in the
figures, the sound pressure level of the solid line with the damping member 21 is improved
compared to the sound pressure level of the dashed line without the damping member 21. I
understand that I am doing. That is, the damping member 21 can suppress the reaction of the
yoke 131 with respect to the diaphragm 15 at around 2 kHz of the resonance frequency f1.
[0039]
In this embodiment, a member having a resonance frequency f2 different from the resonance
frequency f1 is fixed to the yoke 131 having the resonance frequency f1, so that f4 does not
have a specific resonance frequency. Thereby, the diaphragm 15 can suppress the reaction in the
specific frequency band, and can convert it into more accurate air vibration.
[0040]
(Embodiment 2) FIG. 6 is a cross-sectional view for explaining an embodiment 2 of the speaker
device. The same components as in the first embodiment will be described with the same
reference numerals. The same applies to the following embodiments.
[0041]
In the second embodiment, the damping member 21 is fixed to a speaker device in which an
annular cancel magnet 61 is attached to the rear surface of the yoke 131. The cancel magnet 61
is a permanent magnet.
[0042]
The cancel magnet 61 is formed to have substantially the same size as the drive magnet 132 and
has a reverse magnetic pole direction with respect to the magnet 132. That is, when the magnetic
pole direction of the magnet 132 is, for example, N pole on the front side and S pole on the rear
side, the magnetic pole direction of the cancel magnet 61 is S pole on the front side and N pole
on the rear side. And the shield cover 62 is being fixed to the back surface part of the
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cancellation magnet 61 by adhesion ¦ attachment, for example.
[0043]
The shield cover 62 covers the magnet 132 and the cancel magnet 61. The shield cover 62
contributes to downsizing of the speaker box by suppressing the influence of magnetism due to
the magnet 132 and the cancel magnet 61.
[0044]
The shield cover 62 is made of a magnetic material and includes a rear wall 62a and a peripheral
wall 62b projecting forward from the peripheral portion of the rear wall 62a, and the front side
is opened. The shield cover 62 fixes the front surface of the rear wall 62 a to the rear surface of
the cancel magnet 61, and brings the front end of the peripheral wall 62 b close to the peripheral
edge of the top plate 133. Thus, the shield cover 62 covers the magnet 132 yoke 131 and the
cancel magnet 61.
[0045]
The cancel magnet 61 can reduce the leakage flux of the magnet 132 and increase the flux
density in the magnetic gap 18.
[0046]
A damping member 21 is fixed to the opposite surface of the shield cover 62 to which the cancel
magnet 61 is fixed.
The damping member 21 includes an elastic body 21a and a damping plate 21b. The vibration
control plate 21b is tightened and fixed to the shield cover 62 with a screw 23 via an elastic
body 21a made of, for example, butyl rubber.
[0047]
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Here, the diaphragm 15 without the damping member 21 is driven by the magnetic circuit 13 of
the yoke 131 having a resonance frequency f1. Therefore, when the input signal in the band of
the resonance frequency f1 is supplied to the voice coil 14, the yoke 131 makes a reaction of the
voice coil 14. This reaction causes the yoke 131 to absorb the movement of the voice coil 14. In
this case, the diaphragm 15 can not be converted into an accurate air vibration by the reaction of
the magnetic circuit 13, and the faithful reproduction can not be performed.
[0048]
On the other hand, the case where the input signal is supplied to the magnetic circuit 13 when
the damping member 21 is fixed to the shield cover 62 will be considered. The respective
resonance frequencies f1 to f3 of the members of the yoke 131, the elastic body 21a, and the
damping plate 21b in this case can eliminate the occurrence of a specific resonance frequency
band as indicated by Q (f4) in FIG. A cancel magnet 61 and a shield cover 62 are fixed between
the bottom plate 131 a and the damping member 21. However, the reaction of the yoke 131 to
the vibration of the voice coil 14 transmitted through the cancel magnet 61 can be suppressed
by the elastic body 21 a and the damping plate 21 b.
[0049]
In this embodiment, the damping member 21 is fixed to the shield cover 62 via the elastic body
21 a. As a result, even in the speaker device provided with the cancel magnet 61, it is possible to
suppress the vibration of the yoke 131 due to the reaction of the diaphragm 15, and to suppress
the decrease in the sound pressure level.
[0050]
(Third Embodiment) FIG. 7 is a cross-sectional view for explaining a third embodiment of the
speaker device.
[0051]
In this embodiment, a second damping member 72 made of, for example, butyl rubber is
disposed also in the space 71 between the bottom plate 131 a of the yoke 131 and the rear wall
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62 a of the shield cover 62.
The second damping member 72 is fixed in a state of being in pressure contact with the bottom
plate 131a and the rear wall 62a.
[0052]
In this embodiment, the damping member 21 is fixed to the shield cover 62 via the elastic body
21 a. Further, a second damping member 72 is fixed between the bottom plate 131a and the rear
wall 62a.
[0053]
With the space 71 in the bottom plate 131a and the back wall 62a, the reaction of the bottom
plate 131a located in the space 71 is not suppressed. Therefore, in the third embodiment in
which the second damping member 72 is fixed to the space 71, it is possible to suppress the
vibration of the bottom plate 131a located in the space 71.
[0054]
Thereby, even in the speaker device provided with the cancel magnet 61, it is possible to further
suppress the vibration of the yoke 131 due to the reaction of the diaphragm 15, and to suppress
the decrease in the sound pressure level.
[0055]
Although the screw 23 in FIG. 7 is screwed into the shield cover 62, at least a part of the screw
23 is screwed into the bottom plate 131a to make the vibration damping effect by the second
vibration damping member 72 more reliable. It can be
[0056]
(Embodiment 4) FIG. 8 is a cross-sectional view for explaining an embodiment 4 of the speaker
apparatus.
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[0057]
In this embodiment, the projection 62 c of the rear wall 62 a of the shield cover 62 abuts on the
opening 61 a of the annular cancel magnet 61.
The protrusion 62 c is integrally formed with the shield cover 62 by, for example, pressing.
An elastic body 21a is fixed between the projection 62c and the bottom plate 131a.
A convex portion 21b1 integrally formed with the damping plate 21b is fitted in the concave
portion formed by the projection 62c.
[0058]
The damping plate 21 b is screwed and fixed to the bottom plate 131 a of the yoke 131 with the
screw 23. By this screwing, the elastic body 21a is fixed between the bottom plate 131a and the
projection 62c in a pressure-contacted state.
[0059]
In this embodiment, the damping member 21 is directly fixed to the bottom plate 131 a while
being provided with the cancel magnet 61. Therefore, the damping member 21 can suppress the
vibration of the yoke 131 in the same manner as the speaker without the cancel magnet 61, and
can suppress the decrease in the sound pressure level.
[0060]
The elastic body 21a of the damping member 21 is fixed between the projection 62c and the
bottom plate 131a, but may be fixed between the projection 62c and the projection 21b1 of the
damping plate 21b. Conversely, it may be only between the projection 62c and the projection
21b1 of the damping plate 21b. The point is that the vibration of the yoke 131 due to the
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reaction of the diaphragm 15 can be suppressed.
[0061]
(Fifth Embodiment) FIG. 9 is a cross-sectional view for explaining a fifth embodiment according
to a speaker device.
[0062]
In this embodiment, an elastic body 21 a having a thickness filling the space is disposed between
the bottom plate 131 a of the yoke 131 and the rear wall 62 a of the shield cover 62.
That is, the vibration control plate 21b of Embodiment 4 is removed, and the shield cover 62 is
also used as the vibration control plate 21b2.
[0063]
In this embodiment, the damping member 21 composed of the elastic body 21 a and the
damping plate 21 b 2 can suppress the reaction of the yoke 131 to further suppress the decrease
in the sound pressure level. Further, since the shield cover 62 can be used also as the damping
plate 21b2, the number of parts can be reduced.
[0064]
Sixth Embodiment FIG. 10 is a cross-sectional view for explaining a sixth embodiment according
to a speaker device.
[0065]
In this embodiment, the shield cover 62 for the cancel magnet 61 is removed.
Furthermore, the damping member 21 formed of the elastic body 21 a and the damping plate 21
b 2 is fixed to the bottom plate 131 a of the yoke 131 from the opening 61 a of the annular
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cancel magnet 61 of the cancel magnet 61. The damping member 21 is formed so as not to abut
on the inner wall of the cancel magnet 61 and has a diameter larger than that of the center pole
131 b. The material, thickness, and the like of the damping member 21 are, for example, the
same as those described above.
[0066]
Since the damping member 21 is fixed to the bottom plate 131a, the vibration of the yoke 131
due to the reaction of the diaphragm 15 can be suppressed while suppressing the decrease in the
sound pressure level while using the cancel magnet 61. It becomes.
[0067]
In each of the above-described embodiments, the resonance frequency of the yoke and the
control member is exemplified by different materials. However, if an elastic body having a
different resonance frequency is interposed between the yoke and the control member, the yoke
is used. And the control member may be made of a material of similar resonance frequency.
[0068]
The elastic body is exemplified by butyl rubber and silicon rubber, but it may be, for example, a
self-adhesive insulating tape using these materials.
The self-adhesive insulating tape has a slight space in the overlapping portion when the tapes are
stacked, and as time passes, butyl rubber and silicone rubber in the adhesive layer flow little by
little and fill the slight space created. It is a material of the nature which
Although the external magnet type speaker device has been exemplified, it may be an internal
magnet type speaker device.
[0069]
Although several embodiments have been described, these embodiments are presented as
examples and are not intended to limit the scope of the invention. These novel embodiments can
be implemented in various other forms, and various omissions, substitutions, combinations, and
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changes can be made without departing from the scope of the invention. These embodiments and
modifications thereof are included in the scope and the gist of the invention, and are included in
the invention described in the claims and the equivalent scope thereof.
[0070]
11 Speaker 12 Frame 13 Magnetic circuit 131 Yoke 131a Bottom plate 131b Center pole 132
Magnet 133 Top plate 14 Voice coil 15 Diaphragm 16 Damper 17 Edge 18 Magnetic gap 19
Voice coil bobbin 21 Damping member 21a Elastic body 21b, 21b2 Damping plate 22 Screw hole
23 Screw 61 Cancel magnet 62 Shield cover 6271 Space 72 Second damping plate
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