JP2007142982

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DESCRIPTION JP2007142982
A speaker device can be made thinner, the effective length of an edge can be increased, a margin
for the amplitude of the diaphragm can be provided, and even if the power of an input signal is
increased, it can be handled with a margin and little distortion. To provide a speaker device
capable of reproducing high definition sound quality. SOLUTION: An edge 71 constituting an
outer peripheral portion of a diaphragm 41 vibrated by driving a voice coil 45 has a waveform
whose cross-sectional shape has two or more peak portions 72, 72 projecting toward the front of
the speaker. Loudspeaker device 30 configured. [Selected figure] Figure 2
Speaker device
[0001]
The present invention relates to a speaker device.
[0002]
As a general example of the electrodynamic speaker device, a magnetic circuit, a frame holding
the magnetic circuit at the rear, and a cone-shaped diaphragm in which a roll-shaped edge of the
diaphragm outer periphery is fixed to the front of the frame And a voice coil wound around an
axially movable cylindrical voice coil bobbin. The voice coil bobbin is elastically supported by the
frame via a damper for restricting axial movement.
As the damper, one having a bellows structure concentric with the voice coil bobbin is usually
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employed (for example, Patent Document 1). Japanese Patent Application Laid-Open No. 63155900 Japanese Patent Application No. 2003-428374 EP0914020A2
[0003]
By the way, recently, even in-vehicle audio systems have increasingly incorporated speaker
devices for reproducing deep bass, such as woofers and subwoofers. In the case of such an onvehicle speaker device, thinning of the speaker device is considered to be an important issue so
that the speaker device can be incorporated even in a portion where the depth dimension of the
vehicle door, ceiling panel, etc. is limited. There is.
[0004]
However, in the type shown in the above-mentioned patent document 1 in which the vibration
system is supported by the damper, the speaker device is elongated in the axial direction, and the
stiffness of the vibration system is large, and the vibration system is supported by its mechanical
fatigue. It is likely to cause a decrease in performance. Therefore, instead of the damper, an
enclosed space is formed between a pair of diaphragms, and as a damperless speaker device, a
damper-less speaker device supporting the oscillation system using the spring property of the
gas in the enclosed space is realized. The applicant of the invention describes a speaker device
having a structure shown in FIG. 1 in Patent Document 2.
[0005]
The speaker device shown in FIG. 1 is symmetrical with respect to the center line 37, and only
one half of the center line 37 is shown. The speaker device shown in FIG. 1 includes a magnetic
circuit 33 provided with a magnet 53, a frame 35 carrying the magnetic circuit 33, and a
cylindrical voice coil bobbin 45 disposed movably in the axial direction with respect to the
magnetic circuit 33. The voice coil 46 wound around the voice coil bobbin 45 so as to face the
magnetic circuit 33, and the drive member 42 (hereinafter referred to as the drive member 42)
which transmits the drive of the diaphragm 41 and the voice coil 46 arranged along the drive
direction. The space enclosed by the diaphragm 41 and the drive cone 42 and the frame 35 is a
sealed space, and the elasticity of the gas in the sealed space 67 allows the voice coil bobbin 45
to The vibration system is supported. Reference numeral 51 denotes a yoke holding the magnet
53, and 23 denotes a dust cap which covers the central portion of the diaphragm 41 at the front
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of the speaker device.
[0006]
A curved portion having a substantially semicircular longitudinal cross-sectional shape called a
roll edge is formed on the outer peripheral portion of the diaphragm 41 and the drive cone 42,
and the flange portions 61a and 62a extending from the outer ends of the roll edges 61 and 62 It
is fixed to The dimensions and shapes of the roll edges 61 and 62 relate not only to the size of
the front surface of the speaker device, but also to the volume of the enclosed space 67, the
effective vibration area of the diaphragm 41 and the drive cone 42, etc. To influence.
[0007]
However, in the speaker device shown in FIG. 1, the roll edge 61 of the diaphragm 41 has a
single curvature radius at which the center point A of the curvature radius is at the same height
(H0) as the surface of the flange portion 61 a connected to the roll edge 61. The roll edge 62 of
the drive cone 42 is a so-called tall edge in which the center point B of the radius of curvature is
on the edge bulging side of the flange portion 62 a connected to the roll edge 62.
[0008]
As described above, the inside of the closed space between the diaphragms functions as an air
spring, but the volume of the closed space influences the constant of elasticity, that is, the
stiffness.
In addition, the effective vibration area difference between the diaphragm and the drive cone that
form the closed space is also related to the stiffness. Assuming that the effective vibration area of
the diaphragm is S1, the effective vibration area of the drive cone is S2, and the volume of the
enclosed space is V, the spring constant of the air spring in the enclosed space is proportional to
(S1-S2) / V. Further, assuming that the spring constant is s0 and the weight of the vibration
system is m0, the lowest resonance frequency f0 is expressed by f0 = (1 / 2π) × √ (s0 / m0), so
by reducing the spring constant s0. , The lowest resonant frequency can be lowered.
[0009]
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Therefore, in order to reduce the spring constant and lower the lowest resonance frequency, it is
necessary to reduce the effective vibration area difference between the diaphragm and the drive
cone. For this purpose, the roll edge of the diaphragm on the front side of the device has a large
single curvature It is also one method to make it the edge shape of a radius. However, if the
radius of curvature of the roll is simply increased, the height of the edge is increased, the axial
length of the speaker device, in particular, the dimension of the edge coming out of the
attachment surface of the diaphragm is increased, and the thinning of the speaker device is
impaired. In addition, the roll outer diameter and the roll length of the roll edge are restricted in
the specification of the speaker device due to the diameter (drop diameter) of the speaker device
and the drafting taper of the frame. Moreover, although the structure by which the waveform
was provided in the drive cone side by the corrugation damper is described by patent document
3, in this structure, since the effective vibration area by the side of a drive cone becomes small,
the support by an air spring is hard. There is an inherent problem.
[0010]
As a problem to be solved by the present invention, in a speaker device in which a vibration
system is supported by an air spring in a closed space between diaphragms, the support of the
diaphragm is increased without increasing the diameter of the roll of the edge (the size of the
front projection). An example is the problem of making it flexible.
[0011]
In the speaker device according to claim 1, the edge constituting the outer peripheral portion of
the diaphragm which is vibrated by the driving of the voice coil is formed into a waveform having
a cross section having two or more peak portions projecting toward the front of the speaker It is
characterized by being done.
[0012]
According to the present invention, the edge constituting the outer peripheral portion of the
diaphragm vibrated by the driving of the voice coil is formed in a waveform having a crosssectional shape having two or more peak portions projecting toward the front of the speaker. It is
considered to be the best embodiment.
According to this configuration, not only the height of the edge of the diaphragm can be reduced,
and the speaker device can be thinned, but also the reflection of the edge can be reduced, and the
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disturbance of the impedance can be reduced.
In addition, the effective length of the edge can be made longer to allow room for the amplitude
of the diaphragm. As a result, even if the power of the input signal is increased, it is possible to
cope with the room with margin and reproduce high quality sound with less distortion. .
Furthermore, since the amplitude is easy to be oscillated, the lowest resonance frequency f0 is
lowered, which is particularly useful for improving the acoustic characteristics of a speaker
device for reproducing bass such as a woofer or a subwoofer.
[0013]
In the speaker device of this embodiment, the edge can be configured such that a mesh-like
reinforcing member is provided inside the urethane foam. According to the edge of this
configuration, it is possible to obtain sufficient strength and to be easily deformed corresponding
to the displacement of the diaphragm.
[0014]
In the speaker device of this embodiment, the folding angle of the peak portion can be configured
in the range of 50 degrees to 65 degrees. According to this configuration, it is possible to provide
a speaker device having so-called high-quality sound reproduction and durability in which the
elastic function of the plurality of peak portions and the strength increasing function by the
reinforcing member are compatible.
[0015]
In the speaker device of this embodiment, the diaphragm and the drive cone for transmitting the
drive of the voice coil to the diaphragm are provided, and the diaphragm and the outer
peripheral portion of the drive cone are fixed to the diaphragm support on the frame to vibrate
The space enclosed by the plate and the drive cone and the frame is a sealed space, and the
spring system of the gas in the sealed space can be applied to a configuration in which the
vibration system is supported via the voice coil bobbin.
[0016]
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According to this configuration, in the speaker apparatus of the double cone (diaphragm and
drive cone) using the air suspension, the height of the edge of the diaphragm can be lowered, so
that the thinning of the speaker apparatus can be further promoted.
It is possible to provide a speaker device that can be easily installed even in a part having a
limited depth, such as a vehicle door or a ceiling panel of a vehicle. In addition, the effective
length of the edge can be increased, a margin can be provided for the amplitude of the
diaphragm, and even if the power of the input signal is increased, the margin can be coped with
and high-quality sound with little distortion can be reproduced. Furthermore, f0 is lowered
because of easy amplitude, and in particular, the acoustic characteristics of a speaker device for
reproducing low tones such as a woofer and a subwoofer can be improved.
[0017]
Hereinafter, a first example of a preferred embodiment of a speaker device according to the
present invention will be described with reference to the drawings. FIG. 2 is a longitudinal
sectional view of the speaker device according to the embodiment of the present invention. In the
present embodiment, since it is symmetrical, it is shown as a cross-sectional view of a half of the
speaker device. FIG. 3 is an enlarged cross-sectional view of the main part of FIG. As shown in
FIG. 2, the speaker device 30 of this embodiment includes a magnetic circuit 33, a frame 35 to
which the magnetic circuit 33 is attached on the rear inner wall, a diaphragm 41 and a voice coil
46 arranged along the driving direction. Inside the enclosed space 67 which is provided with a
drive cone 42 for transmitting the driving force to the diaphragm 41 and a voice coil 46 wound
around a cylindrical voice coil bobbin 45 and surrounded by the diaphragm 41 and the drive
cone 42 and the frame 35 The vibration system is supported via the voice coil bobbin 45 by the
air spring. Reference numeral 37 denotes a center line of the speaker device 30.
[0018]
The magnetic circuit 33 includes a yoke 51 having a structure in which a cylindrical center pole
51b protrudes from the center of a disk-shaped plate 51a, a ring magnet 53 loosely fitted on the
outer periphery of the center pole 51b, and a plate 51a. And a ring-shaped top plate 55 loosely
fitted on the tip end side of the center pole 51b so as to sandwich the magnet 53 between them.
A gap between the inner periphery of the top plate 55 and the center pole 51 b is a magnetic gap
57 in which the voice coil 46 is disposed.
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[0019]
The magnetic circuit 33 is attached to the inner surface of the bottom plate portion 35a with the
plate 51a of the yoke 51 placed thereon. In the frame 35, the diaphragm support portion 35c of
the diaphragm 41 and the diaphragm support portion 35d of the drive cone 42 are provided at
positions separated along the driving direction.
[0020]
The diaphragm 41 and the drive cone 42 are cone-shaped diaphragms, and the edge 71 of the
outer peripheral portion of the diaphragm 41 has two equal heights that bulge outside the sealed
space 67 between the diaphragms (front side of the speaker device) The roll edge 62 of the outer
peripheral portion of the drive cone 42 is the outside of the sealed space 67 between the
diaphragms (the same as the heights of the top portions 72 b and 73 b). It is a tall edge that
bulges on the back side of the speaker device.
[0021]
In the diaphragm 41 and the drive cone 42, the mounting flanges 71a and 62a connected to the
edge 71 of the outer peripheral portion and the outer end of the roll 62 are fixed to the
diaphragm support 35c and 35d on the frame 35.
[0022]
According to this configuration, the height H of the edge 71 of the diaphragm 41 can be reduced,
and the speaker device 30 can be thinned.
Also, edge reflections are reduced, and impedance disturbances can be reduced.
In addition, the effective length of the edge 71 can be made longer to allow room for the
amplitude of the diaphragm 41. As a result, even if the power of the input signal is increased, it is
possible to cope with the room with margin and reproduce high quality sound with less
distortion. Can. Furthermore, since the amplitude is easy to be oscillated, the lowest resonance
frequency f0 is lowered, which is particularly useful for improving the acoustic characteristics of
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a speaker device for reproducing bass such as a woofer or a subwoofer.
[0023]
The edge 71 is provided with a mesh-like reinforcing member over the entire inner surface of the
urethane foam. According to the edge of this configuration, it is possible to obtain sufficient
strength and to be easily deformed corresponding to the displacement of the diaphragm.
[0024]
The reinforcing member is formed of, for example, any of aromatic polyamide fiber, cotton,
polyester fiber, olefin-based fiber, and nylon fiber. Also, the reinforcing member is any of plain
weave, turtleskin weave and triaxial weave, and is either nonwoven fabric or triaxial weave.
Further, it is manufactured by sandwiching the reinforcing member having the above-described
structure in a thermoplastic resin film and fusing the urethane foam and the reinforcing member
by heat pressure molding.
[0025]
In the first embodiment, the thickness of the edge 71 is, for example, about 1 mm, and the
folding angle α of the peak portions 72 and 73 is in the range of 50 degrees to 65 degrees, and
the folding radius R is, for example, about 1.5 mm. Is configured in size. If the angle is in this
range, the mesh installed as a reinforcing member does not pierce the urethane foam, and the
strength enhancement function of the reinforcing member can be compatible while maintaining
the elasticity of the plurality of peak portions 72 and 73.
[0026]
The diameter of the central opening of the diaphragm 41 disposed on the front side of the
speaker device 30 is set larger than the diameter of the opening of the drive cone 42, and the
drive cone 42 disposed on the back of the diaphragm 41 is The diameter of the opening at the
central portion is set to be approximately equal to the outer diameter of the voice coil bobbin 45.
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[0027]
Further, the inner peripheral portion 41a of the diaphragm 41 is joined to the drive cone 42 in a
state of being superimposed on the drive cone 42 located behind it.
Further, a dust cap 23 is attached to a central portion of the diaphragm 41. The dust cap 23
covers the front of the voice coil bobbin 45 to prevent dust and the like from entering the
magnetic gap 57.
[0028]
By appropriately bonding and fixing the inner peripheral portion 42 a of the drive cone 42 to the
outer periphery of the voice coil bobbin 45 with an adhesive or the like, the diaphragm 41 has a
structure connected to the voice coil bobbin 45 via the drive cone 42.
[0029]
The cylindrical voice coil bobbin 45 is movably fitted in the axial direction and loosely fitted to
the outer periphery of the center pole 51b, and positioning in the radial direction and axial
direction is achieved by the drive cone 42 joined to the outer periphery.
[0030]
As the edge 71 of the diaphragm 41 and the roll edge 62 of the drive cone 42, it is preferable to
use a member made of a material having a high internal loss in order to attenuate the vibration
transmitted from the cone paper which is the diaphragm main body.
Therefore, for example, it is preferable to join members made of a material different from corn
paper (a material having a higher internal loss than corn paper) to form the edge 71 and the roll
62.
[0031]
Next, an example of measurement results of acoustic characteristics of the speaker device of
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Example 1 of the present invention and the speaker device (speaker device shown in FIG. 1) of
the comparative example will be shown.
In the first embodiment, the edge height H is 8.5 mm, the effective edge length is 39.59 mm, the
folding angle α is 60 degrees, and the comparative example is a loudspeaker having a
conventional edge structure as shown in FIG. The apparatus was used, and the edge height H was
12.0 mm, and the effective edge length was 36.23 mm.
[0032]
FIG. 6 is a graph showing the results of measurement of the frequency characteristics of
impedance with respect to the speaker device of Example 1 and the speaker device of the
comparative example (the speaker device shown in FIG. 1). And (b) are the measurement results
of the comparative example. As shown in FIG. 6, the loudspeaker apparatus of Example 1 has less
disturbance of the impedance characteristic in the frequency range of 450 Hz to 500 Hz (the
range indicated by X in the figure) than the loudspeaker apparatus of the comparative example.
Can be seen.
[0033]
In addition, with respect to the speaker device of Example 1 and the speaker device of the
comparative example, the measurement of power linearity indicating the relationship of the
output sound pressure to the input power (input power) was performed at frequencies of 30 Hz,
40 Hz, and 50 Hz. FIG. 7 is a graph showing the measurement results of power linearity, in which
(a) shows the measurement results of Example 1 and (b) shows the measurement results of
Comparative Example.
[0034]
In FIG. 7A, the measured values for each frequency of 30 Hz, 40 Hz, and 50 Hz in the speaker
device of Example 1 are the lines indicated by M30 (30 Hz), M40 (40 Hz), and M50 (50 Hz). The
ideal lines are K30 (30 Hz), K40 (40 Hz) and K50 (50 Hz) represented by thin lines in the figure.
[0035]
Further, in FIG. 7B, the measured values for each frequency of 30 Hz, 40 Hz, and 50 Hz in the
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speaker device of the comparative example are lines shown in RL30 (30 Hz), RL40 (40 Hz), and
RL50 (50 Hz). The ideal lines in the figure are K30 (30 Hz), K40 (40 Hz) and K50 (50 Hz)
represented by thin lines in the figure.
[0036]
As can be seen from the figure, the lines (K30, K40, and K40) exhibit ideal characteristics for
each frequency in the speaker apparatus of Example 1 (FIG. 7A) as compared to the comparative
example (FIG. 7B). The result is close to K50).
[0037]
Further, the lowest resonance frequency f0 was 32 Hz in the speaker device of the first
embodiment, while the speaker device of the comparative example was 40 Hz.
[0038]
Hereinafter, a second example of the preferred embodiment of the speaker device according to
the present invention will be described with reference to FIG.
FIG. 4 is an enlarged cross-sectional view of an edge 81 in a speaker device according to a
second embodiment of the present invention.
The other configurations in the second embodiment are the same as those in the first
embodiment, and thus the description thereof is omitted.
In the second embodiment, the diaphragm 41 and the drive cone 42 are cone-shaped
diaphragms, and the edge 81 of the outer peripheral portion of the diaphragm 41 is outside the
sealed space 67 between the diaphragms (the front side of the speaker device ) Has a corrugation
edge with three ridges 82, 83, 84 of the same height H (the heights of the tops 82b, 83b, 84 are
the same).
Further, R1 of the turn-back portions are all configured to have the same size. Also in the second
embodiment, the same effect as the first embodiment described above can be obtained.
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[0039]
Hereinafter, a third example of the preferred embodiment of the speaker device according to the
present invention will be described with reference to FIG. FIG. 5 is an enlarged cross-sectional
view of an edge 91 in a speaker device according to a third embodiment of the present invention.
The other configurations in the third embodiment are the same as those in the first embodiment,
and thus the description thereof is omitted. In the third embodiment, the diaphragm 41 and the
drive cone 42 are cone-shaped diaphragms, and the edge 91 of the outer peripheral portion of
the diaphragm 41 is outside the sealed space 67 between the diaphragms (the front side of the
speaker device ) Has a corrugation with two ridges 92 and a ridge 93. The two ridges 92 and 93
are formed to have different heights H2 (apex 92b) and height H (apex 93b), and the size of R of
the folded portion is all different, and the folding angles α2, α3 and α4 are different. Are all
configured in different sizes. In this way, not only the same effect as in the first and second
embodiments described above can be obtained if configured, but the size of the peak can be
appropriately adjusted, and the setting contents such as changing the function delicately
Adjustment is possible.
[0040]
As described above in detail, the speaker device 30 according to the embodiment of the present
invention can reduce the height of the edge of the diaphragm in a speaker device of a double
cone (a diaphragm and a drive cone) using an air suspension. Therefore, thinning of the speaker
device can be further promoted. It is possible to provide a speaker device that can be easily
installed even in a part having a limited depth dimension, such as a vehicle door or a ceiling
panel of a vehicle. In addition, the effective length of the edge can be increased, a margin can be
provided for the amplitude of the diaphragm, and even if the power of the input signal is
increased, the margin can be coped with and high-quality sound with little distortion can be
reproduced. Further, f0 is lowered because of easy amplitude, and it is particularly useful for
improving the acoustic characteristics of a speaker device for reproducing low tones such as a
woofer and a subwoofer.
[0041]
The speaker device according to the present invention is not limited to the double cone
(diaphragm and drive cone) speaker device using the air suspension of the above embodiment,
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and can be applied to various other speaker devices. Further, the structure of the edge is not
limited to the shape of the above-described embodiment and can be variously changed.
[0042]
It is a longitudinal cross-sectional view which shows the half part of the speaker apparatus which
comprised the roll edge of the front diaphragm in a roll edge. It is a longitudinal cross-sectional
view which shows the half body of the speaker apparatus based on Example 1 of this invention. It
is an expanded sectional view of the principal part of the speaker apparatus shown in FIG. It is an
expanded sectional view of the principal part of the speaker apparatus concerning Example 2 of
this invention. It is an expanded sectional view of the principal part of the speaker apparatus
concerning Example 3 of this invention. It is a graph which shows the result of having measured
the frequency characteristic of impedance to a speaker apparatus, and (a) is Example 1 of the
present invention, (b) is a measurement result of a comparative example. It is a graph which
shows the measurement result of power linearity, (a) is Example 1 of this invention, (b) is a
measurement result of a comparative example.
Explanation of sign
[0043]
DESCRIPTION OF SYMBOLS 30 Speaker apparatus 33 Magnetic circuit 35 Frame 35c, 35d
Diaphragm support part 41 diaphragm 42 Drive cone (drive member) 45 Voice coil bobbin 57
Magnetic gap 62 Roll edge 67 (of drive cone) 67 Sealed space 71, 81, 91 Edge 72, 73, 82, 83,
84, 92, 93 Yamabe
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