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DESCRIPTION JP2000050384

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DESCRIPTION JP2000050384
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
small and light speaker device, and more particularly to a speaker device in which the sound
pressure of bass of the speaker unit is increased and the influence of the reaction force of the
speaker box is reduced.
[0002]
2. Description of the Related Art In order to suppress the vibration of the baffle board of a
speaker box to which a speaker unit has been attached conventionally, the vibration is performed
in the direction opposite to the vibration direction of the speaker excited by the diaphragm. For
example, a speaker device having a vibrator or a transducer is known and described in detail in,
for example, JP-A-63-212000 and JP-A-1-307398.
[0003]
A speaker device as shown in FIG. 3 is shown in the above-mentioned Japanese Patent
Application Laid-Open No. 63-212000.
In FIG. 3, 1 indicates a ring-shaped magnet, and 2 and 3 indicate a plate and a yoke attached so
as to sandwich the magnet 1 and forming a magnetic gap 4 in a part thereof. The frame 5 of the
speaker unit A is attached to the plate 2, and an edge 6 is provided on the outer peripheral
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portion of the frame 5, and the outer peripheral portion of the cone-shaped diaphragm 7 is held
by the edge 6.
[0004]
On the other hand, a voice coil bobbin 8 is attached to the inner peripheral portion of the
diaphragm 7, a voice coil 9 is wound around the voice coil bobbin 8, and the voice coil 9 is
formed by a plate 2 and a yoke 3. The magnetic gap 4 is inserted. The configurations shown by
reference numerals 1 to 9 above are the basic structure of the known electrodynamic speaker
unit A.
[0005]
One end of a screw 10 is screwed into the center on the back surface side of the yoke 3 of the
speaker unit A, and the other end of the screw 10 is completely free of the magnet 1, plate 2 and
yoke 3 in the speaker unit A described above. A magnetic circuit comprising the magnet 11, the
plate 12 and the yoke 13 of the same configuration is attached.
[0006]
A frame 14 is attached to the plate 12, and further, two dampers 15 and 16 are attached to the
frame 14, and the drive coil bobbin 17 is held by the dampers 15 and 16.
[0007]
A drive coil 18 is wound around one end of the drive coil bobbin 17. The drive coil 18 is inserted
into a magnetic gap 19 formed by the plate 12 and the yoke 13.
A weight 20 is attached to the other end of the drive coil bobbin 17. The vibration system
including the weight 20 is approximately equal to the equivalent mass of the vibration system
including the cone-shaped diaphragm 7 and the like in the speaker unit A. It is done.
The configuration shown above by reference numerals 11 to 20 indicates the electric and
vibration transducer B.
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[0008]
In the above-mentioned configuration, the speaker unit A and the electric / vibration transducer
B are attached to the baffle board 22 of the speaker box 21. Now, if an electric signal is supplied
to the voice coil 9 of the speaker unit A, the voice coil 9 vibrates in the lateral direction in the
figure by a known action to generate a driving force F1 to drive the cone-shaped diaphragm 7 to
reproduce sound. Do.
[0009]
At this time, when the same electric signal is applied to the drive coil 18 in the electric / vibration
transducer B, the drive coil 18 also vibrates in the lateral direction in the figure to generate a
driving force F2 to drive the weight 20 in the same direction. . Here, if the equivalent mass of the
vibration system including the diaphragm 7 and the like in the speaker unit A and the vibration
system including the weight 20 and the like in the electric / vibration transducer B is
substantially equal, the reaction force -F1 received by the speaker unit A by the vibration system
The reaction force -F2 of the vibration system in the electric / vibration transducer B is
approximately equal.
[0010]
Therefore, the reaction which the speaker unit A receives by the drive of the diaphragm 7 is
canceled by the electric / vibration transducer B, and the vibration of the baffle board 22 of the
speaker box 21 and the swing of the speaker box 21 are suppressed. .
[0011]
On the other hand, there is a demand for obtaining an inexpensive speaker system by reducing
the volume of the speaker box 21 and achieving miniaturization, but generally, the volume of the
speaker box 21 is to be reduced. Therefore, the amplitude of the speaker unit A is increased to
suppress the rise of the low frequency reproduction limit.
[0012]
However, by increasing the amplitude of the small-sized speaker, the sound pressure in the
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speaker box 21 rises, and peaks and valleys occur in the frequency characteristic.
As a method for solving such a problem, a speaker apparatus using a speaker box provided with
a push-through radiator to radiate sound without distortion by effectively utilizing sound waves
emitted from the back of the diaphragm of the speaker unit Are also widely used.
[0013]
Further, in the above-mentioned Japanese Patent Application Laid-Open No. 1-307398, the cone
openings of the diaphragms 7 of the two speaker units A are directed in the opposite direction by
the action force F1 of the diaphragm 7 of the first speaker unit A. There is also disclosed a
speaker device in which the reaction force -F1 is canceled by the reaction force -F2 of the
reaction force F2 of the diaphragm 7 of the second speaker unit A.
[0014]
According to the conventional speaker device, the acting force F1 = M1 · α1 (where M1 is the
equivalent mass of the vibration system and α1 is the acceleration of the diaphragm) given to
the diaphragm of the first speaker unit A is magnetic Assuming that the circuit, the frame of the
speaker unit and the speaker box are one rigid body, the reaction force generated on this rigid
body is -F1 = M1 '.. alpha.1' (where M1 is the equivalent mass of the aforementioned rigid body
and .alpha.1 'is the reaction) Given as acceleration).
[0015]
Therefore, the acceleration .alpha.1 'given by the reaction force is subjected to the displacement
of the reaction force -F1 determined by .alpha.1' =-(M1 /M1').alpha. If it is ∞, there is no
influence of reaction force, and the diaphragm changes only by the acceleration given to the
voice coil, but in fact M1 'is finite, and especially the entire speaker device including the speaker
box as described above The weight and size are reduced, the diaphragm becomes heavier, and
the mass ratio M1 / M1 'tends to increase, and the reproduction efficiency of the low region is
largely due to the reaction force -F1 to the acting force F1 of the diaphragm. descend.
[0016]
Furthermore, in reality, the magnetic circuit, the speaker frame, and the speaker box are not one
rigid body, but each has a resonance point, and outputs energy other than reproduced sound as
distortion by energy given by reaction. In particular, this causes a reduction in the output fidelity
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of the reproduced sound to the input signal.
Such problems can be canceled by the two speaker units or the speaker unit and the electric
vibration transducer as described above, but these configurations require two magnetic circuits
and two voice coils and require two drive circuits. Therefore, not only the power consumption
increases, but also the distance between the baffle board of the speaker box and the back plate
increases, which makes it difficult to obtain a miniaturized speaker device.
[0017]
The present applicant has previously proposed a speaker device as shown in FIG. 4 in order to
solve the problem of overhead.
The same reference numerals are given to portions corresponding to the speaker device shown
in FIG. 4 in FIG.
[0018]
FIG. 4 shows a side cross sectional view of the speaker device, and 23 shows such a small
speaker unit as a whole, and the yoke 3 has a cylindrical bottomed side cross section made of a
plate material such as pure iron, and a bottom portion Has a center hole and has an upwardly
convex center pole 24 in order to reduce the weight, and on the center pole 24, the ring-shaped,
light-weighted ring is attached to the N pole and the S pole in the plate thickness direction. The
magnetized magnet 1 is joined via an adhesive or the like, and further, a ring-shaped pole piece
25 is joined on the magnet 1 via an adhesive or the like.
A magnetic gap 4 is formed between the outer diameter portion of the pole piece 25 and the
inner diameter of the cylinder forming the yoke 3.
[0019]
The frame 5 has an opening having an inner diameter substantially the same as the diameter of
the sound release hole 26 formed in the baffle board 22, and three stepped portions 28a, 28b
and 28c are formed in the depth direction of the speaker box 21. In order to gradually reduce the
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diameter of the opening of the step portion, it is made of steel or the like in a substantially funnel
shape.
[0020]
A magnetic circuit 27 formed by the magnet 1, the yoke 3 and the center pole 24 and the pole
piece 25 is suspended on the frame 5 by two corrugated ring-shaped second and third dampers
15 and 16. .
That is, the outer diameter portions of the dampers 16 and 15 are joined to the bottom of the
frame 5 and the third step 28c, and the inner diameter portions of the dampers 16 and 15 are
joined to the top and bottom of the cylindrical portion of the yoke 3 of the magnetic circuit 27.
[0021]
Furthermore, the voice coil 9 wound around the voice coil bobbin 8 is inserted into the magnetic
gap 4 of the magnetic circuit 27 and suspended on the frame 5 by the first ring-shaped damper
29 joined to the top of the voice coil bobbin 8. It is made to do.
[0022]
That is, a voice coil bobbin including the voice coil 9 by joining the inner diameter portion of the
first damper 29 to the upper end outer diameter portion of the voice coil bobbin 8 and the outer
diameter portion to the second stepped portion 28b of the frame 5 8 is made swingable in the
longitudinal direction of the voice coil bobbin 8 within the magnetic gap.
[0023]
The inner diameter portion of the funnel-shaped first diaphragm 7 is bonded to the upper end
outer diameter of the voice coil bobbin 8 with an adhesive or the like, and the ring-shaped edge 6
is formed on the outer periphery of the first diaphragm 7. The outer peripheral portion of the
edge 6 is joined to the first stepped portion 28 a of the frame 5 via an arrow.
[0024]
Further, a concave dust cap 32 is joined to the inclined portion of the first diaphragm 7 so as to
cover the upper part of the voice coil bobbin 8.
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[0025]
Further, the second diaphragm 30 is fixed to the bottom of the magnetic circuit 27 so that the
funnel-shaped openings face in the opposite direction to each other so as to face the first
diaphragm 7.
[0026]
In FIG. 4, the bottom of the funnel-shaped diaphragm 30 is fixed to the bottom of the yoke 3 with
a screw 34 via the disk 33.
[0027]
As described above, the speaker unit 23 is composed of one magnetic circuit 27 and one voice
coil 9 mounted so that the openings of the first and second diaphragms 7 and 30 face in the
opposite direction. The baffle board 22 of the speaker box 21 is fixed to face the sound output
hole 26 pierced.
[0028]
Further, the first stepped portion 28a of the frame 5 of the speaker unit 23 is fixed to the inside
of the baffle board 22 via the screw 36.
[0029]
Furthermore, free of the edge 31 of the second diaphragm 30 on the outside of the ring-shaped
fixed plate 38 fixed to the sound release hole 37 formed at the position opposite to the sound
release hole 26 in the back plate 35 with the screw 36. The outer peripheral portions in the state
are joined to constitute the speaker device 40.
[0030]
With this configuration, if an acoustic signal is supplied to the voice coil 9, the reaction force -F1
= M1 '.. alpha.1 that is exerted when the action force of F1 = M1..alpha.1 acts on the first
diaphragm 7 The second diaphragm 30 including the magnetic circuit 27 is displaced in the
opposite direction by the amount of '.
[0031]
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Therefore, it is possible not only to avoid the influence of the reaction force -F1 given to the
magnetic circuit 27 which is the cause of the distortion in the conventional configuration but also
to use the second diaphragm 30 for the acoustic energy acting as the reaction force -F1. Since it
is possible to emit sound through it, it is possible to improve the electro-acoustic conversion
efficiency.
Further, since the speaker box 21 is not affected by the reaction force -F1 'of the first diaphragm
7, there is no need to increase the equivalent mass of the speaker device 20 including the
speaker box 21, and the depth direction becomes thinner. It is possible to reduce the size and
weight as in a bookciel type speaker device.
[0032]
According to the speaker unit 23 having the configuration of FIG. 4 described above, the second
diaphragm 30 including the magnetic circuit 27 is used as the second damper 30 for the second
and third dampers. There is a problem that it is necessary to hold at 15 and 16 and a large
number of parts are required when configuring one speaker unit, and the assembly becomes
complicated.
[0033]
The present invention is intended to provide a speaker device which solves the problems of
overhead, and the problem to be solved by the invention is to simplify the assembly with a simple
speaker configuration and to set the depth direction of the speaker box In addition to improving
the electro-acoustic conversion efficiency, it is possible to effectively utilize the reaction force to
the action force of the diaphragm, and the low-frequency reproduction is expanded, and a smallsized lightweight speaker device with little distortion can be obtained. It is said that.
[0034]
[Means for Solving the Problems] The speaker according to the present invention has a
diaphragm of a speaker unit opposed to a speaker sound emission hole formed in a baffle board
of a speaker box, and a magnetic circuit of this speaker unit A push-blad radiator is disposed on
the back.
[0035]
According to the speaker device of the present invention, the speaker unit can be simplified and
the assembly to the speaker box can be extremely facilitated by disposing the push-through
radiator as the second diaphragm on the back of the speaker unit. The speaker unit can be
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miniaturized, the electro-acoustic conversion efficiency can be improved, and the reaction force
of the action force of the diaphragm can be offset by the speaker unit of one magnetic circuit and
one voice coil and one drive source. What can be reduced in size by narrowing the depth
between the baffle board and the back plate of the box is obtained.
[0036]
BEST MODE FOR CARRYING OUT THE INVENTION One embodiment of a speaker device
according to the present invention will be described below with reference to FIGS. 1 and 2. FIG.
The parts corresponding to the speaker device shown in FIG. 3 are indicated by the same
reference numerals.
[0037]
The speaker unit A used in FIG. 1 may be a speaker unit having the same structure as that
described in detail in FIG. 3. However, in FIG.
That is, a cancel magnet 42 magnetized in the thickness direction opposite to the magnetizing
direction of the drive magnet 1 is joined to the back side of the yoke 3 via an adhesive and the
magnetic circuit 27 is surrounded by the cup-shaped shield case 43. A normally magnetically
shielded speaker unit A is configured such that a magnetically closed circuit is formed so that the
outer periphery of the plate 2 and the inner diameter of the shield case 43 are in contact with
each other so that the magnetic flux does not cross to the outside.
[0038]
Further, the back plate 35 of the speaker box 21 facing the shield case 43 of the magnetic circuit
27 of the speaker unit A functions substantially as the center of the magnetic circuit 27 in order
to function as a pushback radiator (passive radiator). As a standard, the back plate functions as a
pushback radiator by setting it as a circular, square, rectangular, etc. drone cone of a
predetermined diameter provided with a flexible portion 46 on the back plate 35, and a flexible
portion 46 provides a predetermined stiffness. Will form a
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[0039]
Further, the speaker unit A is fixed in the speaker box 21 via the frame 5 so as to face the sound
output hole 26 formed in the baffle board 22 of the speaker box 21.
[0040]
First and second ducts 44 and 45 constituting a phase inversion type speaker box are
concentrically disposed below the sound output hole 26 to which the speaker box A is attached.
[0041]
That is, among the first and second ducts 44 and 45, the first duct 44 and the opening 44a of the
duct are integrally formed with the baffle board 22.
[0042]
In the back plate 35, a second duct 45 having a larger duct diameter than the first duct 44 is
formed so as to overlap within a predetermined length of the first duct 44 and to have a
concentric cross section. Of the air flow to the opening 44a of the first duct 44 through the
opening 45a of the second duct 45 so as to increase the equivalent mass MD and the equivalent
resistance RD of the air to form a bent duct. doing.
[0043]
In the speaker box 21 of the above-described configuration, the reaction force of the duct
radiation forces FD1 and FD2 between the first duct 44 and the second duct 45-FD1 and -FD2
are mutually offset, and the lightweight speaker box 21 is Since it does not swing back and forth
by radiation action force FD1 and reaction force -FD1 at the time of air radiation from opening
44a of a duct, since it mutually countered with the 2nd duct 45, it looked as speaker box 21
Sometimes, the balance with the reaction force -F1 with respect to the action force F1 at the time
of sound emission of the speaker unit A may be taken into consideration.
[0044]
According to the speaker device 40 having the configuration of FIG. 1, the sound radiation force
when the speaker unit A fixed in the speaker box 21 is driven is given by F1 = M1 · α1 as
described above.
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Naturally, the reaction force -F1 of this sound radiation force is generated.
[0045]
Accordingly, with this reaction force -F1, the push-blower 30 generates the air radiation force F2
and naturally generates this reaction force -F2.
[0046]
Now, assuming that the equivalent mass of this push-up radiator 30 is M2, the acceleration
applied to this push-up radiator 30 is α2, and the compliance (spring constant) is K, the speaker
unit A is driven to emit sound. When the action force F1 = M1 · α1 acts on the diaphragm 7, the
push-blower 30 receives the action force F2 = M2 · α2 with a reaction force −F1 as an
excitation force.
At this time, naturally, a reaction force of -F2 = M2 · α2 works.
[0047]
Therefore, the reaction force -F1 of the action force F1 at the time of sound radiation of the
speaker unit A and the reaction force -F2 of the sound radiation force F2 of the push-up radiator
30 cancel each other by setting F1 FF2. Can be attenuated.
[0048]
Accordingly, since F1 F F2 and M1 · α1 M M2 · α2, M2 can be appropriately selected by
selection of α2. For example, if α1 = α2, then M2 = M1 may be selected.
[0049]
Further, the resonance frequency f 02 of the push-blower 30 described above can be obtained as
the equation (2).
Therefore, by selecting this value between the lowest resonance frequency f0 of the speaker unit
A and the resonance frequency fD0 of the duct generated in the duct, emphasizing the sound
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pressure in the low band without lowering the low band reproduction frequency. Is possible.
In this case, it is more effective to match the resonance frequency f02 of the push-blower 30 with
the lowest resonance frequency f0 of the speaker unit A.
[0050]
In the configuration of FIG. 1, since the push-through radiator 30 is not attached to the side of
the baffle board 22 as usual, the back plate 35 of the speaker box 21 functions as a passive
radiator and the reaction force of the speaker unit A It becomes possible to generate an acting
force F2 which can cancel or dampen F1.
[0051]
The flexible portion 46 is formed by corrugating corrugations at the time of molding of the
speaker box 21 or the back plate 35 so as to be thinly molded, or the edge of synthetic resin or
the like similar to the free edge is a passive radiator 30 It may be made to stick between the
outer peripheral part of the back plate 35 and the back plate 35.
[0052]
FIG. 2 shows another embodiment of the speaker apparatus of the present invention.
The speaker unit A is the same as the configuration of FIG. 3, and the configurations of the first
and second ducts 44 and 45 constituting the double duct of this example are mutually disposed
opposite to the baffle board 22 and the back plate 35 The radiator 30 is provided on the middle
plate 49 interposed between the back plate 35 and the back surface of the magnetic circuit 27 of
the speaker unit A.
[0053]
In the speaker box 21 of this embodiment, the middle plate 49 is disposed between the top plate
22U and the bottom plate 22D so that the volume of the speaker box 21 is approximately half,
and the middle plate 49 has a predetermined stiffness (spring constant K The flexible portion 46
to give) is molded into a thin corrugated, for example, circular, square, etc. synthetic resin (ABS)
etc. in the same manner as corrugation, and the interior surrounded by the flexible portion 46 is
a drone cone and the push-up radiator 30 is Configure.
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[0054]
Furthermore, a duct opening 45a is formed in the back plate 35 opposed to the first duct 44
provided on the baffle board 22 so that the second duct 45 is integrated with the back plate 35. .
[0055]
Even in the speaker device 40 having the configuration shown in FIG. 2, the reaction force -F1 of
the sound radiation force F1 of the speaker unit A excites the reaction force -F1 to the pash brad
radiator 30 which is the drone cone of the mid plate 49. An acting force F2 is generated as a
source.
Further, as an equivalent circuit of the push-blad radiator 30, the equivalent mass M2 of the
drone cone portion and the equivalent resistance R2 and the compliance C2 of the flexible
portion are connected in series and indicated by FD3 to be coupled to the equivalent circuit of
the speaker unit A. An action force is also generated.
Therefore, if this reaction force -F2 =-(M2 · α2 + FD3) becomes -F1 − -F2-(M2 · α2 + FD3) with
respect to the reaction force-F1 of the speaker unit A The reaction force -F1 due to the sound
radiation force F1 is offset or attenuated with the force F2 of the push-blower 30.
[0056]
Also in the case of FIG. 2, by radiating the first and second ducts 44 and 45 in the opposite
directions, FD1 = FD2 holds, so the duct parts are mutually balanced so that -FD1 and -FD2
cancel each other out immediately. Can be attenuated, and it is only necessary to consider the
balance between the speaker unit A and the push-through radiator 30.
[0057]
Now, let the equivalent mass of the push-up radiator 30 be M2, the effective area be SD3, the
acceleration acting on the drone cone (the push-out radiator not including the flexible portion
46) be α2, the acceleration acting on the push-out radiator be αD3. Then, the above-mentioned
acting force FD3 is here, and S is an effective area of the diaphragm 7 of the speaker unit A.
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[0058]
Therefore, in order to set -F1 ≒ -F2, it is sufficient to satisfy the equation (3).
Also, if -F2 .gtoreq.-F1, the value of -F1-(-F2) is added to the sound radiation force F1 of the
speaker unit A so that a very strong bass can be radiated.
[0059]
Here, the reason why F2 is added to F1 is that αD3 = S / SD3 · α1. Therefore, F1 = M1 · α1 =
M2 · α2 can be obtained as α2 = M1 / M2 · α1.
Therefore, the acting force F2 of the radiation of the push-up radiator 30 is increased by M2 · S /
SD3 · α1 and added to the sound radiating force F1 of the speaker unit A.
[0060]
According to the speaker device of the present invention, the flexible plate and the
predetermined equivalent mass and equivalent resistance are given to the back plate of the
speaker box, and the speaker unit is arranged swingably on the back surface of the speaker unit.
The speaker device can be made to function as a push-up radiator, raise the sound pressure of
the bass, and support the reaction force of the sound radiation force of the speaker unit to
prevent the light speaker box from swinging. Be
Further, by functioning as a pushback radiator, it is possible to provide a speaker device in which
the bass radiation effect is enhanced.
[0061]
Brief description of the drawings
[0062]
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1 is a side sectional view of the speaker device of the present invention.
[0063]
2 is another side sectional view of the speaker device of the present invention.
[0064]
3 is a partial cross-sectional view of the conventional speaker device.
[0065]
4 is a side sectional view of the conventional speaker device.
[0066]
Explanation of sign
[0067]
A: Speaker unit 7: 7. Diaphragm 21: Speaker box 22: Baffle board 27: Magnetic circuit 30: Pash
radiator 35: Back plate 40: Speaker device
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