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DESCRIPTION JP2010136013

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DESCRIPTION JP2010136013
[PROBLEMS] To provide a “speaker” capable of achieving both a reduction in thickness and a
high power, as well as preventing distortion of reproduced sound and having a long damper life.
A speaker which elastically supports a voice coil 4 from the outer side in the radial direction by a
waveform damper 6 having a sloped shape, and the waveform damper 6 has a peak portion
along a substantially conical surface which is tapered toward the front. It has an appearance in
which 6a and valleys 6b are alternately arranged concentrically, and the peaks 6a have convex
surfaces forward, and the valleys 6b have concave surfaces forward. However, the mountain
portion 6a is formed as a gentle curved portion larger than the valley portion 6b. Further, on the
inner peripheral side of each valley portion 6b, there is formed a substantially cylindrical
standing wall portion 6c which stands slightly inclining upward, and this standing wall portion 6c
is continuous with the outer peripheral side of the peak portion 6a. There is. The inner periphery
of the wave damper 6 is joined to the front end of the bobbin 3, and the outer periphery of the
wave damper 6 is joined to the bottom plate of the frame 2. [Selected figure] Figure 1
スピーカ
[0001]
The present invention relates to a thin speaker suitable as an on-vehicle subwoofer or the like,
and more particularly to a speaker supporting a voice coil by means of an inclined wave damper
which tapers forward toward the front.
[0002]
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A cylindrical voice coil is loosely inserted in the magnetic gap of the speaker, and this voice coil
is axially driven by electromagnetic force and vibrates when energized.
The voice coil is wound on, for example, a cylindrical bobbin (coil bobbin), and the inner
periphery of the diaphragm is joined to the front end of the bobbin, so the inner periphery of the
diaphragm is integrated with the voice coil . The outer peripheral portion (edge portion) of the
diaphragm is elastically supported by the frame of the speaker, and the reproduction sound is
emitted by being driven by the voice coil and the diaphragm vibrating. Also, usually the inner
periphery of the damper is also joined to the front end of the bobbin, and the outer periphery of
this damper is fixed to the frame (or magnetic circuit), so the voice coil is elastically supported by
the damper ing. As a damper, a corrugation shaped damper (waveform damper) having peaks
and valleys alternately arranged concentrically along a radial direction is generally used, and this
type of damper is taken along a plane substantially orthogonal to the axial direction.
Loudspeakers having a damper structure are widely adopted in which a cylindrical voice coil is
supported from outside in the radial direction. Thus, when the voice coil supported by the
damper is driven in the axial direction by the electromagnetic force, the damper elastically
expands and contracts following the voice coil.
[0003]
However, in the speaker supporting the voice coil by the damper disposed along a plane
substantially orthogonal to the axial direction, when the speaker is thinned, the damper is a
magnetic circuit when the amplitude of the vibration system increases. There is a risk of contact
with the diaphragm. Therefore, it is not preferable to use this type of damper when designing a
vehicle-mounted subwoofer or the like that requires a large amplitude for the vibration system
while being thin, and it is desirable to make it thinner and have higher power (larger amplitude)
The damper structure which can achieve coexistence of is needed.
[0004]
Therefore, conventionally, there has been proposed a speaker having a structure in which a voice
coil is supported by a wave-shaped damper having an inclined shape which narrows forward
toward the front (see, for example, Patent Document 1). Such an inclined wave-shaped damper
has an appearance in which peaks and valleys are alternately arranged concentrically along a
substantially conical surface which is tapered toward the front, and an outer peripheral portion
on the rear end is joined to a frame or a magnetic circuit Since the inner peripheral portion on
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the front end side is joined to the front end portion of the bobbin, the waveform damper does not
easily contact the magnetic circuit or the diaphragm even at large amplitude. Therefore, by using
such an inclined waveform damper, it is possible to make the speaker thinner without sacrificing
the maximum amplitude of the vibration system. Japanese Patent Application Laid-Open No. 10155198
[0005]
As described above, since the inclined waveform damper is difficult to contact the magnetic
circuit and the diaphragm even when the amplitude is large, it can be said that it is an effective
means to achieve both thinning of the speaker and high power, but it has been conventionally
used There is a problem that distortion is likely to occur in the reproduced sound because the
method of changing the stiffness of elastic deformation in front of the stationary position and
elastic deformation in rear of the stationary position is extremely different. That is, in such a
conventional example, the stiffness of the waveform damper tends to increase when the driven
vibration system moves forward, and the stiffness of the waveform damper tends to decrease
when the vibration system moves backward. When it is displaced backward than when displaced
forward, the reaction force of the wave damper is not received. As a result, the vibration system
is difficult to move in front of the stationary position and easy to move in the rear, so that
unbalanced vibration occurs back and forth, which adversely affects the reproduced sound.
[0006]
Further, in the case of the conventionally used inclined waveform damper, when the vibration
system is largely moved to the rear of the stationary position, the stiffness becomes so small that
the central holding force (holding force for the voice coil) is weakened. It is easy to cause rolling,
which also causes distortion in the reproduced sound.
[0007]
Furthermore, in the case of the conventionally used inclined waveform damper, when the
vibration system moves a large distance to the rear of the stationary position, stress concentrates
on the valley of the outermost periphery joined to the frame (or magnetic circuit) Because of the
risk of buckling, there is room for improvement in terms of the life of the wave damper.
[0008]
The present invention has been made in view of the circumstances of the prior art as described
above, and an object thereof is to achieve both a reduction in thickness and a high power, as well
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as a speaker which hardly causes distortion in reproduced sound and has a long damper life. It is
to provide.
[0009]
In the present invention, a cylindrical voice coil is elastically deformed from the radially outer
side by an inclined waveform damper having an appearance in which peaks and valleys are
alternately concentrically arranged along a substantially conical surface which is tapered forward
toward the front. In the speaker of the structure to support in a continuous manner, the peak
part of the waveform damper is formed as a large curved part that is gentler than the valley part,
and a standing wall extending from the valley part to the outer peripheral side of the peak is
provided to this waveform damper It had been formed, and the standing direction of this
standing wall was set so as to be slightly inclined inward with respect to the axial direction of the
voice coil.
[0010]
According to the speaker of the present invention, when the driven vibration system is displaced
to the rear of the stationary position, the elastic repulsive force of the peak can be enhanced by
the standing wall portion of the waveform damper, and the vibration system is at the stationary
position. Since the peak portion can be elastically deformed without being greatly affected by the
standing wall when being displaced forward, the stiffness of the wave damper is elastically
deformed in the forward and backward positions of the stationary position. It can be changed
approximately symmetrically.
In addition, it is easy to prevent the rolling, which is a concern when the vibration system has
largely moved backward.
Therefore, this speaker is less likely to cause distortion in the reproduced sound even when the
amplitude is large, and it is easy to achieve both thinning and high power.
Further, since the rising direction of the standing wall portion of the waveform damper is slightly
inclined inward with respect to the axial direction of the voice coil in this speaker, the stress is
concentrated when the vibration system is largely moved backward. The valley portion at the
outermost periphery can be reinforced by the upstanding wall portion rising obliquely forward,
whereby the life of the wave damper can be extended.
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[0011]
According to the present invention, a magnetic circuit having a magnetic gap, a frame fixed to the
magnetic circuit, a cylindrical voice coil loosely inserted in the magnetic gap and movable in an
axial direction, and an outer peripheral portion is elastic on the frame A diaphragm in which the
inner circumference is integrally supported by the voice coil, and the appearance in which peaks
and valleys are alternately concentrically arranged along a substantially conical surface which
narrows forward toward the front, An outer peripheral portion is fixed to the frame or the
magnetic circuit, and an inner peripheral portion is a waveform damper integrated with the voice
coil, and the voice coil is elastically supported from the radial direction outer side by the
waveform damper In the speaker, the wave-shaped damper is erected from the valley portion
between the peak portion having a convex surface facing forward and the valley portion adjacent
to an outer peripheral side of the peak portion and having a concave surface facing forward.
Vertical wall leading to the mountain The rising direction of the standing wall portion is set to be
slightly inclined inward with respect to the axial direction, and the peak portion is formed as a
large curved portion gentler than the valley portion. Was configured.
[0012]
In the speaker thus configured, when the driven vibration system is displaced to the rear of the
stationary position and the radius (curvature radius) of the peak portion of the waveform damper
is small, the vibration system moves to the rear. Along with this, since the elastic repulsive force
of the peak portion is increased by the influence of the standing wall portion, the stiffness of the
wave damper can be gradually increased.
Further, since the peak portion of the waveform damper 6 is formed as a large curved portion
that is gentler than the valley portion, the standing wall portion is raised when the vibration
system is displaced forward of the stationary position and the radius of the peak portion is large.
The ridges can be elastically deformed without much influence.
Moreover, since there is no possibility that the stiffness of the wave damper becomes extremely
small even if the vibration system moves largely to the rear, the center holding power for the
voice coil can be maintained and rolling can be easily prevented. That is, this speaker not only
achieves both thinning and high power by using a wave-shaped damper with an inclined shape
that narrows forward toward the front, but also when elastically deforming the wave-shaped
damper in front of the stationary position Since the stiffness can be changed approximately
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symmetrically when elastically deformed in the rear and back, distortion does not easily occur in
the reproduced sound even at a large amplitude. In addition, since the rising direction of the
standing wall portion of the waveform damper is slightly inclined inward with respect to the axial
direction of the voice coil, the valleys on the outermost periphery of the waveform damper where
stress concentrates when the vibration system largely moves backward. The part can be
reinforced by the upstanding part which stands up diagonally forward, so that the valley part is
less likely to buckle and the damper life can be extended.
[0013]
In the above configuration, the angle between the rising direction of the standing wall portion of
the waveform damper and the axial direction of the voice coil can be selected to an appropriate
value according to the material, size, etc. of the waveform damper. If it is set in the range of 25
degrees (more preferably about 10 degrees), the elastic repulsive force of the peak portion
increases when the vibration system is displaced to the rear of the stationary position, and the
outermost periphery of the waveform damper It is preferable because buckling of the valley can
be effectively prevented.
[0014]
An embodiment will be described with reference to the drawings. FIG. 1 is a partial sectional view
of a speaker according to a first embodiment of the present invention, and FIG. 2 is a correlation
between the stiffness of a waveform damper used in the speaker and the displacement of a voice
coil. FIG. 7 is a characteristic diagram showing a comparative example together with FIG.
Although FIG. 1 shows the cross-sectional structure of the right half of the speaker, the left half
(not shown) has a similar cross-sectional structure that is line-symmetrical to this. Further, in FIG.
2, a value obtained by replacing stiffness with a spring constant is shown on the vertical axis, and
a backward displacement of the voice coil from a stationary position is shown as a positive value,
and a forward displacement is shown on the horizontal axis as a negative value. .
[0015]
The speaker shown in FIG. 1 is wound around a magnetic circuit 1 having a magnetic gap G, a
frame 2 fixed to a top plate 12 of the magnetic circuit 1, and a cylindrical bobbin 3 and loosely
inserted in the magnetic gap G. The voice coil 4, the diaphragm 5 whose inner periphery is joined
to the front end of the bobbin 3 and the outer periphery is joined to the front end of the frame 2,
and the inner periphery is joined to the front end of the bobbin 3 It is mainly composed of a
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waveform damper 6 whose portion is joined to the bottom plate portion of the frame 2 and a
dustproof dust cap 7 covering the front of the bobbin 3.
[0016]
The magnetic circuit 1 includes a yoke 11 including a center pole portion 1 a, a disk-shaped top
plate 12 having a central portion open, and an annular ring interposed between a bottom plate
portion of the yoke 11 and the top plate 12. The magnetic gap G is formed between the outer
peripheral surface of the center pole portion 1 a and the inner peripheral surface of the top plate
12.
Further, the bottom plate portion of the frame 2 is firmly fixed to the top plate 12.
[0017]
The voice coil 4 is electrically connected to an external circuit by a lead wire (not shown). When
the voice coil 4 is energized, an electromagnetic force acts, and the voice coil 4 is integrated with
the bobbin 3 by the electromagnetic force. It is driven to vibrate in the axial direction
(longitudinal direction). At that time, the waveform damper 6 supporting the front end portion of
the bobbin 3 elastically expands and contracts following the vibration of the voice coil 4.
[0018]
The diaphragm 5 is made of cone paper or the like, and the inner peripheral portion of the
diaphragm 5 is integrated with the voice coil 4 via the bobbin 3. An edge portion 5a which is
easily elastically deformed is attached to the outer peripheral portion of the diaphragm 5, and
since the edge portion 5a is joined to the frame 2, the outer peripheral portion of the diaphragm
5 is elastically supported by the frame 2 It is done. When the diaphragm 5 is driven by the voice
coil 4 at the time of energization and vibrates, reproduced sound is emitted.
[0019]
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The wave damper 6 is a frusto-conical damper having an appearance in which peak portions 6 a
and valley portions 6 b are alternately and concentrically arranged along a substantially conical
surface which narrows forward toward the front. The peak 6a is convex on the front, and the
valley 6b is concave on the front. However, the mountain portion 6a is formed as a gentle curved
portion larger than the valley portion 6b. In addition, a substantially cylindrical standing wall
portion 6c is formed on the inner peripheral side of each valley portion 6b so as to be slightly
inclined inward and stands up, and this standing wall portion 6c is continuous with the outer
peripheral side of the peak portion 6a . The angle α between the standing direction of the
standing wall 6c and the axial direction of the voice coil 4 is set to about 10 degrees. A portion of
the waveform damper 6 protruding inward from the innermost peak portion 6a is joined to the
bobbin 3 and integrated with the voice coil 4 and protrudes outward from the outermost valley
portion 6b. The part is fixed to the top plate 12 by being joined to the frame 2. As a result, the
cylindrical voice coil 4 is elastically supported from the radially outer side by the inclined
waveform damper 6.
[0020]
Since the waveform damper 6 is designed in such a shape, when the driven voice coil 4 is
displaced to the rear of the stationary position and the radius (curvature radius) of the peak
portion 6 a is small, the voice coil 4 is The elastic repulsive force of the peak portion 6a is
gradually increased by the standing wall portion 6c of the wave damper 6 as it moves rearward.
That is, as shown in FIG. 2, when the vibration system is displaced backward by energization of
the voice coil 4 (when the distance x is a positive value), the spring constant of the waveform
damper 6 indicated by the solid line A is The vibration system gradually increases as it moves
backward. On the other hand, the spring constants of the conventional inclined waveform
damper (comparative example) having the same overall shape as the waveform damper 6 but
equal in size of the peaks and valleys and without the standing wall 6c are shown in FIG. As
indicated by the broken line B in FIG. 2, the voice coil 4 tends to decrease as it moves backward.
[0021]
Further, in the present embodiment, when the vibration system is displaced forward (when the
distance x is a negative value), the radius of the peak portion 6a is large and thus the standing
wall portion 6c is not affected so much. The peak 6a can be elastically deformed, so that the
spring constant of the wave damper 6 increases as the vibration system moves forward as in the
comparative example. Therefore, as shown by the solid line A in FIG. 2, the method of changing
the spring constant is almost symmetrical between the case of elastic deformation in front of the
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stationary position and the case of elastic deformation in the rear direction. ing.
[0022]
As described above, in the loudspeaker according to this embodiment, when the driven vibration
system is displaced to the rear of the stationary position, the elastic repulsive force of the peak
portion 6 a is enhanced by the standing wall portion 6 c of the waveform damper 6. Therefore,
the stiffness of the waveform damper 6 can be gradually increased as the vibration system moves
backward. Further, since the peak 6a of the waveform damper 6 is formed as a gentle and large
curved portion than the valley 6b, the standing wall 6c is not significantly affected when the
vibration system is displaced to the front of the stationary position. The peak 6a can be
elastically deformed. Moreover, since there is no possibility that the stiffness of the waveform
damper 6 becomes extremely small even if the vibration system largely moves to the rear, the
center retaining force for the voice coil 4 can be maintained and rolling can be easily prevented.
That is, this speaker not only achieves both thinness and high power while using the waveshaped damper 6 having a sloped shape which narrows forward toward the front, but also
elastically deforms the wave-shaped damper 6 in front of the stationary position. Since the
stiffness can be changed approximately symmetrically when being elastically deformed at the
time of rearing and backward, distortion does not easily occur in the reproduced sound even at
large amplitude, and hence it is suitable as a vehicle-mounted subwoofer.
[0023]
Further, in the loudspeaker according to the present embodiment, since the rising direction of
the standing wall portion 6c of the waveform damper 6 is slightly inclined inward with respect to
the axial direction of the voice coil 4, the vibration system largely moves backward. The valley
portion 6b on the outermost periphery of the wave damper 6 where the stress is concentrated
can be reinforced by the upstanding wall portion 6c that stands up obliquely to the front.
Therefore, in this speaker, the valley portion 6b of the waveform damper 6 is less likely to be
buckled, and the damper life can be extended.
[0024]
In the present embodiment, the angle α between the upstanding direction of the upstanding wall
6 c and the axial direction of the voice coil 4 is set to about 10 degrees, but this angle depends
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on the material, size, etc. of the waveform damper 6. It can select suitably within the limits of 525 degrees. However, when this angle is set to about 10 degrees, the elastic repulsive force of
the peak 6a is increased when the vibration system is displaced to the rear of the stationary
position, and the valley 6b of the outermost periphery of the waveform damper 6 Is preferable
because it can effectively prevent the buckling of the
[0025]
FIG. 3 is a partial cross-sectional view of a loudspeaker according to a second embodiment of the
present invention, in which the parts corresponding to FIG.
[0026]
In the loudspeaker according to the second embodiment shown in FIG. 3, the shape of the outer
peripheral portion (rear end portion) of the waveform damper 6 joined to the frame 2 is different
from that of the first embodiment described above.
That is, in the second embodiment, the portion protruding outward from the peak portion 6 a of
the outermost periphery of the waveform damper 6 is joined to the bottom plate portion of the
frame 2. Also in this case, when the vibration system moves largely backward, stress
concentrates on the valley 6b on the outermost periphery of the waveform damper 6 (the valley
6b adjacent to the inner periphery of the ridge 6a on the outermost periphery). Since the valley
portion 6 b can be reinforced by the standing wall portion 6 c that stands diagonally forward, the
damper life can be extended.
[0027]
The present invention relates to a damper structure of a speaker, and the structure of the
magnetic circuit 1 and the shape of the frame 2 can be selected as appropriate.
[0028]
It is a fragmentary sectional view of the speaker concerning a 1st example of the present
invention.
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It is a characteristic view which shows the correlation of the stiffness of the waveform damper
and displacement of a voice coil which were used by the speaker concerning a 1st example with
a comparative example. It is a fragmentary sectional view of the speaker concerning a 2nd
example of the present invention.
Explanation of sign
[0029]
Reference Signs List 1 magnetic circuit 2 frame 3 bobbin 4 voice coil 5 diaphragm 6 waveform
damper 6 a peak 6 b valley 6 c vertical wall G magnetic gap
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