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DESCRIPTION JP2000013887

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DESCRIPTION JP2000013887
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
suitable speaker and speaker device incorporated in a small and light speaker box, and in
particular, to easily arrange the speaker and the reaction force of the sound radiation force of the
speaker diaphragm. TECHNICAL FIELD The present invention relates to a speaker and a speaker
device configured to cancel or attenuate.
[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 is conventionally attached, the vibration is applied in a 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 described in detail in, for example, Japanese
Patent Application Laid-Open Nos. 63-212000 and 1-307398.
[0003]
The above-mentioned Japanese Patent Application Laid-Open No. 62-212000 shows a speaker
apparatus as shown in FIG.
In FIG. 13, 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
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speaker A is attached to the plate 2, an edge 6 is provided on the outer peripheral portion of the
diaphragm 7, and the outer peripheral portion of the conical diaphragm 7 is held by the frame 7
by the edge 6 There is.
[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
loudspeaker 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 A, and the other end of the screw 10 has the same configuration as the magnet 1, plate 2
and yoke 3 in the speaker A described above. A magnetic circuit consisting of a magnet 11, a
plate 12 and a yoke 13 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, and 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, and a vibration system
including the weight 20 is substantially equal to an equivalent mass of a vibration system
including the cone-shaped diaphragm 7 in the speaker A. ing.
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 configuration, the speaker 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 A, the voice coil 9 vibrates in the lateral direction in the figure by a known action
to generate a driving force F1 and drives the cone-shaped diaphragm 7 to perform sound
reproduction. .
[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 A and the vibration
system including the weight 20 and the like in the electric / vibration transducer B is
approximately equal, the reaction force −F1 received by the speaker A by the vibration system
The reaction force -F2 of the vibration system in the vibration transducer B is approximately
equal.
[0010]
Therefore, the reaction which the speaker 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]
Further, in the above-mentioned Japanese Patent Application Laid-Open No. 1-307398, the
reaction force -F1 generated by the action force F1 of the diaphragm of the first speaker with the
cone openings of the diaphragms of the two speakers directed in the opposite direction is There
is also disclosed a speaker device which is canceled by the reaction force -F2 of the action force
F2 of the diaphragm of the second speaker.
[0012]
SUMMARY OF THE INVENTION In the above-described conventional speaker device, there is a
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demand for reducing the volume of the speaker box 21 and achieving miniaturization and
obtaining an inexpensive speaker device. As the box volume is reduced, the low frequency
reproduction limit is increased, thereby increasing the speaker amplitude.
[0013]
However, by increasing the amplitude of the small-sized speaker, the sound pressure in the
speaker box 21 rises, and peaks and valleys occur in the frequency characteristic.
As a method of solving such a problem, a speaker device is also widely used which radiates a low
frequency band without distortion by effectively using sound waves emitted from the back of the
diaphragm using a phase inversion type speaker box. There is.
[0014]
In order to incorporate the speaker shown in FIG. 13 into the above-described small-sized phasereversal type speaker box 21, a pair of speakers A and an electric vibration transducer B having
substantially the same structure as described in JP-A 1-307398. The pair of speakers must be
disposed back to back, and the depth direction of the speaker box becomes large, which makes it
difficult to miniaturize and expensive.
[0015]
Further, in the two loudspeakers in which the vibration system of the speaker is equally made,
the higher the lowest resonance frequency f0 of the vibration system, the higher the resonance
sharpness Q in proportion to f0. There was a harmful effect.
[0016]
The present invention seeks to provide a loudspeaker and a loudspeaker apparatus which solves
the problems of overhead, and the problem to be solved by the invention is to use the single
loudspeaker to transition the loudspeaker f0 to the low frequency side. It is an object of the
present invention to provide a speaker and a speaker device capable of performing expansion of
a low band and high quality low band radiation and preventing swing of a lightweight speaker
box.
[0017]
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The speaker according to the present invention is a speaker composed of a vibration system
including a diaphragm and a magnetic circuit, and the action force in the reaction direction of the
vibration plate of the vibration system with respect to the sound radiation direction. The vibrator
is arranged in the magnetic circuit in which the.
[0018]
The speaker apparatus according to the present invention is composed of a vibration system
including a diaphragm and a magnetic circuit, and a speaker in which a vibrating body is
disposed in this magnetic circuit is built in a speaker box, and a speaker according to the reaction
direction to the sound radiation direction of the speaker. The vibration of the box is absorbed by
the vibrator.
[0019]
According to the loudspeaker and the loudspeaker apparatus of the present invention, the
miniaturization of the loudspeaker is achieved and the electro-acoustic conversion efficiency is
improved, and the sound of the diaphragm with one magnetic circuit, one voice coil and one
vibrator is obtained. The reaction force of the radiation force can be offset or attenuated, and the
device can be miniaturized by narrowing the depth between the baffle board and the back plate
of the speaker box.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION One embodiment of a speaker and a speaker
device according to the present invention will be described below with reference to FIGS.
The parts corresponding to the speaker device shown in FIG. 13 are indicated by the same
reference numerals.
[0021]
FIG. 1 shows a side cross-sectional view of the speaker of this embodiment, and A shows the
small speaker of this embodiment as a whole, and the yoke 3 has a disk-like portion made of a
plate material such as pure iron and the like. A cylindrical center pole 3a erected at a central
position and a magnet guide 3b consisting of a step formed concentrically with the center pole
3a in a disk shape are integrally formed.
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[0022]
A ring-shaped driving magnet 1 magnetized in the thickness direction of ferrite or the like is
adhered onto the disc-like portion of the yoke 3 described above via an adhesive.
The inner diameter of the ring-shaped drive magnet 1 is fitted to the step of the magnet guide
portion 3b formed in the disk-like portion of the yoke 3 and positioned.
[0023]
The plate 2 is joined to the driving magnet 1.
In this case, the gap guide is kept inserted in the center pole 3a, an adhesive is applied to the
upper surface of the driving magnet 1, and the inner diameter of the plate 2 is inserted into the
outer diameter of the gap guide and fixed.
The plate 2 is made of pure iron or the like in the form of a disk, and is a punched plate material
having a through hole at the center and a voice coil bobbin 9 in a magnetic gap 4 formed
between the inner peripheral edge of the through hole and the outer diameter of the center pole
3a. Is provided.
[0024]
The metal part of the magnetic circuit is constituted by fixing the frame 5 formed in a funnel
shape with steel or the like to the plate 2, and the outer periphery of the center pole 3 a and the
inside of the magnet 1 under the magnetic gap 4. A first space 24 a surrounded by a
circumference is formed.
[0025]
A voice coil 8 wound around a cylindrical voice coil bobbin 9 is inserted into the magnetic gap 4
of the above-mentioned magnetic circuit, and an air-permeable damper 23 having a corrugated
corrugation which can swing in the vertical direction is formed. The voice coil bobbin 9 is held
through.
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[0026]
The inner diameter portion of the damper 23 is bonded to the upper end of the voice coil bobbin
9 via an adhesive, and the outer diameter portion is bonded to the outer periphery of the bottom
portion of the frame 5.
Furthermore, the inner diameter of a funnel-shaped diaphragm 7 with a free or fixed edge 6
made of paper or the like is joined to the upper outer diameter of the voice coil bobbin 9, and the
largest diameter of the diaphragm 7 is the upper opening rim of the frame 5. The gasket 25 is
fixed via a gasket 25.
[0027]
Further, in the present invention, the vibrator 26 is inserted and fixed from the opening of the
voice coil bobbin 9 on the top of the center pole 3a through the adhesive or screw 10.
[0028]
The vibrator 26 shown in FIG. 1 is made of synthetic resin and screwed to the top of the center
pole 3a with a screw 10 through a through hole 33 bored in the bottom of the bottomed cylinder
27a, and the opening of the bottomed cylinder 27a. A ring-shaped movable plate 27b is formed
integrally with the bottomed cylinder 27a at the outer peripheral portion of the plurality of
concentric circular waves of synthetic resin similarly to the damper 23. A ring-shaped weight 20
is formed on the outer periphery of the movable plate 27b. Are bonded with an adhesive or the
like.
[0029]
The vibrating body 26 shown in FIG. 1 can also be configured, for example, as shown in the
perspective view of FIG.
[0030]
The vibrating body 26 shown in FIG. 11A is formed of synthetic resin or the like into one body,
and has a mounting disk portion 32 having a diameter smaller than the inner diameter of the
voice coil bobbin 9 and a cylindrical portion communicating with the mounting disk portion 32.
11 and the disk portion 30 formed on the upper portion of the cylindrical portion 31 and the
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radial portion 29 radially extended from the disk portion 30 to the ring portion 28 and
integrated on the ring portion 28 (FIG. In A), for example, a ring-shaped weight 20 is joined to
the lower side, and a through hole 33 is bored at the center of the mounting disk portion 32, the
cylindrical portion 31, and the disk portion 30.
[0031]
In the above-described vibrator 26, the movable plate 27b and the convergent portion 29
function as a spring to give appropriate stiffness S, and the weight 20 portion to give an
equivalent mass M.
[0032]
In the speaker A shown in FIG. 1, the voice coil 9 is connected to the input terminal 35 through
the tinsel wire 34. Therefore, by supplying an acoustic signal to the input terminal 35, the
diaphragm 7 has, for example, the arrow F1. The sound radiation force of F1 = M1..alpha.1 works
in the direction shown (where M1 is the equivalent mass of the vibration system of the speaker
A, and .alpha.1 is the acceleration acting on the diaphragm 7 of the speaker A).
Thus, the reaction force -F1 shown by the arrow acts on the diaphragm 7.
[0033]
In the present invention, the vibration body 26 is fixed to the center pole 3a constituting the
magnetic circuit of the speaker A, and since the fixing portion is formed to the vibration system
of the speaker A, the function of the vibration system is stopped. F2 = M2 · α2 in the opposite
direction to the sound radiation force F1 = M1 · α1 in the F1 direction of the diaphragm 7 due to
inertia (where M2 is the equivalent mass of the vibrating body 26 and α2 is the movable plate
27b of the vibrating body 26 The reaction force -F2 shown by the arrow acts on the vibrating
body 27 by the acceleration acting on the weight 20 including.
[0034]
Therefore, the reaction force -F1 for the sound radiation force F1 of the diaphragm 7 and the
reaction force -F2 acting on the movable plate 27b of the vibration member 26 are mutually
changed by setting F1 = M1 · α1 F F2 = M2 · α2. It can be offset or attenuated.
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[0035]
That is, according to the present invention, the reaction force -F1 generated by the diaphragm 7
can be eliminated simply by fixing the simple oscillator 26 to the magnetic circuit.
[0036]
FIG. 2 is a side sectional view showing another embodiment of the speaker according to the
present invention. The corresponding parts to those in FIG.
[0037]
In FIG. 2, the loudspeaker A has exactly the same structure as that of FIG.
In this example, the magnetic circuit is fixed to the bottom surface of the yoke 3 with a screw 10
through a through hole 33 formed in a bottomed cylinder 27a of a vibrating body 26 shown in a
perspective view of FIG.
[0038]
The vibrator 26 shown in FIGS. 2 and 11B has substantially the same shape as that described in
FIG. 1, and the length of the bottomed cylinder 27b made of synthetic resin is shorter than that
in FIG. The movable plate 27b made of synthetic resin and formed continuously with the open
outer periphery of the bottomed cylinder 27a has a ring portion 28 concentric with the outer
peripheral portion, and the cross section is concentrically similar to a general damper of a
speaker A corrugation in the shape of a mountain is applied to give adequate stiffness.
On the lower side of the ring portion 28, a ring-shaped weight 20 giving an equivalent mass is
attached.
Of course, the above-mentioned movable plate 27b may be configured like a convergent portion
29 as in FIG. 11 (A).
[0039]
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9
Although the movable plate 27b of the vibrating body 26 is integrally formed with the bottomed
cylinder 27a in the above configuration, the movable plate 27b formed of a cloth like the damper
23 of the speaker is on the outer periphery of the bottomed cylinder 27. It may be made to join
via adhesives etc.
[0040]
Also in the configuration shown in FIG. 2, the reaction force -F1 for the sound radiation force F1
of the diaphragm 7 and the reaction force -F2 for the reaction force F2 of the vibrating body 26
are mutually different. It is possible to cancel or attenuate.
[0041]
FIG. 3 shows still another embodiment of a speaker for achieving the same purpose as in FIGS. 1
and 2. In FIG. 3, the vibration body 26 similar to that described in FIG. 2 is cancelled. It is fixed to
the shielding case 36 of the magnetic circuit provided with the magnet 45 through the screw 10.
[0042]
In the case of FIG. 3, since the structure of the vibrating body 26 is the same as that of FIG. 11B,
the corresponding parts are indicated by the same reference numerals.
Only differences from the speaker A in FIG. 2 will be described below.
[0043]
First, the damper 23 of the speaker A of this embodiment is made airtight by impregnating the
surface of the damper such as cloth with the resin solution to make it airtight, and the lower first
space portion of the damper 23 (between the damper 23 and the plate 2) Of the cancel magnet
45 and the bottom surface of the yoke 3 and the bottom surface of the shield case 36 which are
joined to the bottom surface of the yoke 3 and the bottom surface of the yoke 3 via an adhesive.
The second space 24 b surrounded by the above is communicated through the through hole 37
formed in the yoke 3 to keep the first and second spaces 24 a and 24 b airtight, and the
diaphragm 7 is Provide compliance.
[0044]
The ring-shaped cancel magnet 45 joined to the lower side of the yoke 3 is magnetized in such a
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manner that the same poles as the magnet 1 face each other, and the cylindrical portion of the
cup-shaped shield case 36 is formed. The inner diameter and the outer periphery of the plate 2
are joined so as to be of the same polarity.
[0045]
Also in the configuration of FIG. 3, the reaction forces -F1 and -F2 of the sound radiation force F1
and the action force F2 of the vibrating member 26 support each other by setting -F1 − -F2 and
the first and second The action force shown by F3 and -F3 corresponds to the vibration direction
of the diaphragm 7 of the speaker A because air is compressed and expanded in the airtight
space by the through holes 37 formed in the yoke 3 between the space 24a and 24b. As a result,
these are added to the acting force F2 of the vibrator 26 or the sound radiation force F1 of the
diaphragm 7 to further enhance the radiation force of the bass.
[0046]
FIG. 4 shows still another example of the construction of the loudspeaker according to the
present invention. The construction of the loudspeaker A is the same as that of FIG. 1, and the
construction of the vibrating body 26 will be described below with reference to FIGS. Refer to the
description.
[0047]
In this embodiment, four through holes 39 are formed at positions dividing the outer peripheral
side surface of the cylindrical portion 38 having substantially the same inner diameter as the
outer periphery of the disk portion of the yoke 3 as the vibrator 26 into four. The opening 38 is
fitted to and joined to the outer periphery of the yoke 3, and the movable plate 27b having the
same structure as the damper is integrally formed with the cylindrical portion 38, and the
columnar weight 20 is disposed at the central portion The weight 20 may be integrated with the
movable plate 27b and the cylindrical portion 38 with synthetic resin or the like.
[0048]
According to the speaker A of the above-described configuration, acoustic compliance is formed
in which the air between the movable plate 27b of the vibrating body 26 and the yoke 3 is
restrained by the volume VC.
[0049]
Therefore, the sound radiation force F1 of the diaphragm 7 and the action force F2 of the
vibrating member 26 can be balanced by setting F1 = M1αα1 ≒ F2 = M2 ・ α2.
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[0050]
Further, since the displacement of the weight 20 portion of the movable plate 27b of the vibrator
26 due to the swing may be X / 2, assuming that the amplitude of the speaker A is X, the volume
VC is equal to S2 cm2 of the area of the movable plate 27b. Then, the volume changes by VC = X
/ 2.
Therefore, when the diaphragm 7 of the speaker A is not driven, the volume VC becomes, and if
this variation is ΔVC and the pressure in the volume is P, the pressure in the volume VC
decreases by P−ΔVC / VC It will be.
[0051]
The pressure variation as described above is released or sucked from, for example, four through
holes 39 formed in the cylindrical portion 38 of the vibrating body 26, and the acting force of F3
/ 4 is applied to one through hole 39. It will affect horizontally.
[0052]
Therefore, if the four through holes 39 are opened 90 degrees apart from each other, the force
swinging in the vertical and horizontal directions orthogonal to the mounting direction of the
speaker A should be attenuated or canceled. It will also be possible.
[0053]
FIG. 5 shows still another structure of the speaker A of this embodiment. In the structure of FIG.
4, the speaker 26 is made transparent to the outer diameter portion of the cylindrical portion 38
shown in FIG. This is a case where the hole 39 is not bored, and an acoustic compliance
constrained by the volume VC is provided between the movable plate 27b of the vibrator 26 and
the yoke 3.
[0054]
Also in this case, the reaction force -F1 of the sound radiation force F1 of the diaphragm 7 causes
the reaction force -F1 of the vibrating body 26 to act, and the reaction force -F1 of the
diaphragm F1 becomes F1 ≒ by the reaction force -F2 of the vibration body 26. It becomes
possible to cancel or attenuate by setting it as F2.
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[0055]
Assuming that the effective area of the airtight damper 23 is SD, the effective area of the
movable plate 27b is S2, and the area of the diaphragm 7 is S1 in the configuration of FIG. 5, the
amplitude of the diaphragm 7 is X Assuming that the diaphragm 7 of the speaker is S1 · X, and
the damper 23 and the movable plate 27b are supported on one side, the damper 23 changes by
SD · X / 2 and the movable plate 27b changes by S2 · X / 2.
[0056]
Accordingly, the effective area of the diaphragm 7 of the speaker A is equivalently increased, and
the effective area of the diaphragm 7 which is equivalently enlarged is S0, and the speaker
equivalently increased. The effective area S0 of A is S1 + SD / 2 + S2 / 2, and the rate of change
of the air in the speaker box 21 when the speaker A is inserted into the small volume speaker
box 21 is increased.
[0057]
FIG. 6 shows a speaker A having the configuration of FIG. 5, in which through holes 37 are
formed in the disk-like yoke 3 in the same manner as FIG. 3, and the acoustic compliance of the
air in the first space 24a and the vibrator 26 is obtained. To communicate with the volume VC
constituting the
Furthermore, an appropriate number of through holes 46 may be formed at angular positions
where a predetermined radius is equally spaced n from the central position of the highly airtight
damper 23 as necessary.
[0058]
In the speaker of the configuration shown in FIG. 6 in which the through hole 46 is not formed in
the damper 23, the movable plate 27b of the vibrating member 26 is F2 = M2 due to the reaction
force -F1 to the sound radiation force F1 of the speaker A. The radiation force of .alpha.2 (where
M2 is the equivalent mass of the vibrator 26 and .alpha.2 is the acceleration applied to the
movable plate 27b) works, and this reaction force -F2 cancels out or attenuates the reaction force
-F1 of the diaphragm 7 described above.
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[0059]
Therefore, if -F1 − -F2-F3 (where F3 is the radiation force of air in the through hole 37 formed
in the yoke 3), the diaphragm 7 is obtained according to the condition -F1> -F2 or -F1 <-F2. In
addition to supporting or attenuating the reaction force -F1 of the sound radiation force F1 and
supporting the reaction force, a powerful bass can be emitted by adding the radiation force of F1
-F2 to the sound radiation force F1.
[0060]
Further, as shown in FIG. 6, in the speaker A having a configuration in which a plurality of
through holes 37 are formed in the yoke 6 and a plurality of through holes 46 are formed in the
highly airtight damper 23, X by the effective area SD of the damper 23 A volume change of air of
1/2 SD occurs in the first space 24a, and this radiation force is used as a driving source to
generate F4 / n (n is the number of through holes) in the through holes 46.
Therefore, if -F1.apprxeq .- (F2 + F3 + F4), the reaction force -F1 of the sound radiation force F1
of the speaker A can be canceled or attenuated.
[0061]
Furthermore, as shown by the arrow 47, the air resistance is as shown by the arrows 47 between
the outer diameter of the center pole 3a of the magnetic gap 4 and the inner diameter of the
voice coil bobbin 9 and the inner diameter of the plate 2 and the outer diameter of the voice coil
8. Can be added to reduce the Q0 at the f0 of the speaker A.
[0062]
FIG. 7 is a side sectional view showing still another structure of the speaker A of the present
invention, and the structures of the speaker A and the vibrating body 26 are substantially the
same as FIG. 5, but FIG. 7 shows the yoke 3 and the movable plate 27b. A synthetic resin foam
48 is provided between them.
[0063]
FIG. 8 is a side sectional view showing still another structure of the loudspeaker according to the
present invention. In the vibrator 26, a cylindrical bellows 49 having a corrugated cross section
is fixed to the bottom of the yoke 3 constituting the magnetic circuit. A disc-shaped weight 20 is
joined to the opening of the bellows 49.
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14
[0064]
FIG. 9 shows still another structure of the speaker A of this example, and since the structure of
the speaker A is the same as that of FIG. 4, the structure of the vibrating body 26 is shown in FIG.
The configuration will be described.
[0065]
9 and 11D, the flange portion 40 is formed at the upper position of the cylindrical portion 38,
the hollow portion 41 is provided at the central portion, and the cylinder is formed via the edge
42. The outer periphery of the hollow portion 41 is held at the lower end of the ring-shaped
portion 38, and the outer periphery of the hollow portion 41 is joined to the inner periphery of
the corrugated ring-shaped airtight damper 43, and the outer periphery of the airtight damper
43 is held by the flange portion 40 The disc-shaped weight 20 is comprised.
[0066]
The opening of the cylindrical portion 38 of the vibrating body 26 is fitted to the outer
peripheral portion of the yoke 3 and joined via an adhesive or the like.
[0067]
In FIG. 10, the cylindrical portion 38 is attached to the lower side of the shield case 45 of the
speaker A with cancel magnet shown in FIG. 3, and an edge 42 is provided around the disk-like
weight 20 to open the opening of the cylindrical portion 38. The vibrator 26 is joined to the
bottom of the shield case 36 and the weight 20 to provide acoustic compliance of a volume VC.
[0068]
Even with the loudspeakers shown in FIGS. 9 and 11D and 10, as in the loudspeakers A in FIGS.
Back cavity portion 44 of air volume VC is formed between the bottom plate of case 36 for
weight and weight 20, and weight 20 held by edge 42 and damper 43 generated for sound
radiation force F1 generated when diaphragm 7 is driven. The air of the volume VC in the back
cavity 44 with respect to the acting force F2 enters and exits from the through hole 50 pierced at
the center of the hollow portion 41 or the shield case 36 and receives the through hole of the
hollow portion 41 and the acting force F2. The radiation force F5 of air generated at the through
hole 50 is added, and it becomes possible to increase the striking force of -F2 with respect to -F1.
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15
[0069]
In the above-described respective configurations, the single configuration of the loudspeaker A
has been described. However, the above-described loudspeakers of the present embodiment are
enclosed in the closed loudspeaker box 21 as shown in FIG. 13 or ducts as shown in FIG. If the
speaker box 21 is disposed in the phase-reversal type speaker box 21, the depth direction of the
speaker box 21 is greatly reduced, and a compact and lightweight speaker device can be easily
obtained.
[0070]
FIG. 12 shows a side sectional view in which the speaker A operating on the same principle as
described above is disposed in the speaker box 21 having the phase inversion type duct 51 and
the duct opening 51a.
[0071]
In the speaker box 21 shown in FIG. 12, the above-described speakers may be attached facing
the speaker sound emission holes formed in the baffle board 22. In FIG. 12, the magnetic circuit
of the speaker A is configured. The vibrator 26 attached to the back surface of the yoke 3 is a
weight formed in a disc shape of the ring-shaped air-tight foam 50 of synthetic resin and the
front side of the ring-like air-tight foam 50 20 and forms an airtight volume VC between the yoke
3 and the disc-like weight 20.
[0072]
Now, assuming that the effective area of the diaphragm 7 is S1, the amplitude of the diaphragm 7
is X1, the effective area of the disk-shaped weight 20 of the oscillator 26 is S2, and the amplitude
of the weight 20 is X2, the diaphragm 7 is In order to offset or attenuate the reaction force -F1
with respect to the sound radiation force F1, as described above, F1 .apprxeq.F2, F1 = M1
.alpha.1 .apprxeq.F2 = M2.alpha.2, and M1 = M2.
[0073]
Also, the back surface of the yoke 3 is pulled backward if the static pressure in the volume VC is
P, and the radiation force indicated by F2 of the oscillator 26 is excited by the reaction force -F1
of the sound radiation force F1. And cancel or attenuate each other as -F1.apprxeq.-F2.
[0074]
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16
Further, since the air radiation force FD1 and the reaction force -FD1 are generated at the
opening 51a of the duct 51, the air radiation force FD1 of the duct 51 is added to the sound
radiation force F1 of the diaphragm 7 and F1 + FD1 ≒ F2 You can think of it as
Now, assuming that the cross-sectional area of the duct 51 is SDU (here, MDU is the air
equivalent mass of the duct 51, and αDU is the acceleration of the air at the opening 51a of the
duct 50)
[0075]
Accordingly, the equivalent mass of the weight 20 of the vibrator 26 can be determined as
follows.
[0076]
According to the speaker of the present invention, the reaction force of the sound radiation of the
speaker can be canceled or attenuated by the reaction force of a simple vibrating member
disposed before and after the magnetic circuit. The sound radiation power can be made larger
than usual, and the low range can be expanded, and the voice coil for driving can support the
reaction force of the sound radiation of the speaker by an unnecessary structure like the electric
vibration transducer, and For example, it is possible to obtain a thing capable of suppressing the
oscillation in the vertical and horizontal directions, for example, in the direction orthogonal to the
sound radiation force.
[0077]
Brief description of the drawings
[0078]
1 is a side sectional view of the speaker of the present invention.
[0079]
2 is another side sectional view of the speaker of the present invention.
[0080]
3 is another side sectional view (I) of the speaker of the present invention.
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[0081]
4 is still another side sectional view (II) of the speaker of the present invention.
[0082]
5 is still another side sectional view (III) of the speaker of the present invention.
[0083]
6 is still another side sectional view (IV) of the speaker of the present invention.
[0084]
7 is another side sectional view (V) of the speaker of the present invention.
[0085]
8 is another side sectional view (VI) of the speaker of the present invention.
[0086]
9 is yet another side sectional view (VII) of the speaker of the present invention.
[0087]
10 is yet another side sectional view (VIII) of the speaker of the present invention.
[0088]
11 is a perspective view of a vibrator used for the speaker of the present invention.
[0089]
12 is a side sectional view of the speaker device of the present invention.
[0090]
13 is a partial cross-sectional view of the conventional speaker device.
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[0091]
Explanation of sign
[0092]
A: Speaker, B: electric vibration transducer, 7 .: diaphragm, 20: weight, 26: vibrator, 27a: cylinder
with a bottom, 27b: movable plate
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