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DESCRIPTION JPH1132388

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DESCRIPTION JPH1132388
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
small and light speaker apparatus in which a small speaker unit and a vibrator are incorporated
in a cabinet or the like.
[0002]
2. Description of the Related Art In order to suppress the vibration of a baffle board of a cabinet
to which a speaker unit is conventionally attached, a vibrator or a vibrator which vibrates in a
direction opposite to the vibration direction of the speaker excited by a diaphragm. For example,
a speaker device having a transducer is described in detail in, for example, Japanese Patent
Application Laid-Open Nos. 63-212000 and 1-307398.
[0003]
A speaker device as shown in FIG. 7 is shown in the above-mentioned Japanese Patent
Application Laid-Open No. 62-212000.
In FIG. 7, 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
portion of the frame 5, and the outer peripheral portion of the cone-shaped diaphragm 7 is held
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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 bobbin 8, and the voice coil 9 is in the magnetic
gap 4 formed by the plate 2 and the yoke 3. Is inserted in the
[0005]
The configurations shown by reference numerals 1 to 9 above are the basic structure of the
known electrodynamic speaker unit A.
[0006]
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 has the same configuration as the magnet 1,
plate 2 and yoke 3 in the speaker unit A described above. A magnetic circuit comprising a
magnet 11, a plate 12 and a yoke 13 is attached.
[0007]
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.
[0008]
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. The vibration system
including the weight 20 is substantially equal to the inertia mass of the vibration system
including the cone-shaped diaphragm 7 and the like in the speaker unit A. It is done.
The configurations shown above by reference numerals 11 to 20 indicate the electric / vibration
transducer B.
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[0009]
In the above configuration, the speaker unit A and the electric / vibration transducer B are
attached to the baffle board 22 of the cabinet 21.
Now, when 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 operation, and the cone-shaped
diaphragm 7 is driven to reproduce sound.
[0010]
At this time, when the same electrical 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 drawing, and
drives the weight 20 in the same direction.
Here, if the inertia 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, reaction, electricity and vibration received by the
speaker unit A by the vibration system The reaction of the vibration system at the transducer B is
approximately equal.
[0011]
Therefore, the reaction which the speaker unit A receives by the drive of the diaphragm 7 is
canceled by the electric and vibration transducer B, and the vibration of the baffle board 22 of
the cabinet 21 is suppressed.
[0012]
On the other hand, there is a demand for obtaining an inexpensive speaker system by reducing
the volume of the cabinet 21 and achieving miniaturization, but generally, as the volume of the
cabinet 21 is reduced, the speaker unit A To increase the low frequency reproduction limit so as
to suppress the rise of the low range regeneration limit.
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[0013]
However, by increasing the amplitude of the small-sized speaker, the sound pressure in the
cabinet 21 increases, and peaks and valleys occur in the frequency characteristics.
As a method to solve such a problem, a speaker device using a phase-reversal type bass reflex
cabinet to effectively utilize the sound wave emitted from the back of the diaphragm to radiate
the low frequency region without distortion is also widely used. ing.
[0014]
SUMMARY OF THE INVENTION In order to miniaturize the speaker unit and the speaker device,
the volume of the cabinet 21 is reduced, and when it is configured to be lightened with plastic or
the like, the speaker device as shown in FIG. The back surface of the cabinet 21 swings due to the
sound pressure P emitted from the back surface of the damper 16 of the vibration transducer B
and the diaphragm 1 of the speaker unit A.
[0015]
Since the sound pressure in the cabinet 21 increases in inverse proportion to the volume of the
cabinet 21, the volume in the cabinet 21 decreases, and if the sound pressure increases, the back
surface of the cabinet 21 vibrates at a specific frequency, and If it reaches, the entire cabinet 21
is shaken and oscillated, and the cabinet moves, causing a problem that the sound quality of the
bass deteriorates.
[0016]
SUMMARY OF THE INVENTION The present invention provides a speaker device that solves the
above-mentioned problems, and the problem to be solved by the present invention is that the
sound pressure can be increased and the sound quality is improved in the small and light speaker
device. A small and light cabinet is not moved, and it is an object of the present invention to
obtain a speaker device with strong emission in the low frequency range.
[0017]
A speaker device according to the present invention is a speaker device having a vibrator
configured to perform excitation in a direction opposite to the vibration direction of a diaphragm
of a speaker unit. The unit is mounted on the baffle board and the vibrator is fixed in the cabinet.
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[0018]
According to the present invention, it is possible to obtain a speaker apparatus which is not
rocked by the vibration of the speaker unit A even in a small and lightweight cabinet.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION A speaker device according to the present
invention will be described below with reference to FIGS.
FIG. 1 shows a block diagram of an example of the present invention. A speaker unit A is
mounted on a speaker mounting hole 24 formed on the upper side of a baffle board 22 fixed to
the front of a small lightweight cabinet 21 made of synthetic resin or the like. Is attached, and a
vibrator or an electric / vibration transducer (hereinafter referred to as a vibrator) B is fixed in
the cabinet 22.
[0020]
The structure of the vibrator B will be described later, but it is formed on a support plate 25
having a substantially L-shaped cross section fixed to an upper surface plate (top plate) 21a
formed of left, right, front, rear, front and back The diaphragm 7B of the vibrator B is attached to
the baffle board side.
The opening 26 may be formed in the support plate 25, but the stiffness of the air in the cabinet
21 on the rear surface of the diaphragm 7 A of the speaker unit A and the stiffness of the air on
the front surface of the diaphragm 7 B of the vibrator B are matched. The low resonance
frequency f0 of the vibrator B and the speaker unit A is matched.
[0021]
Of course, the mounting direction of the vibrator B may be such that the opening of the coneshaped diaphragm 7B is directed to the side of the back plate 21b opposite to that in FIG.
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In this case, the exciter B is configured to have the same magnetization direction of the speaker
unit A and the magnet, and the electric input can be input in the same phase.
Furthermore, although not shown, the opening of the diaphragm 7B may be fixed to the side of
the back plate 21b or the baffle board 22 on the support plate 25 standingly fixed to the left and
right side plates or the bottom plate (bottom plate).
[0022]
In addition, an opening and a duct 23 are formed on the same side as the speaker mounting hole
24 of the baffle board 22 so that the phase of the sound emitted from the back of the speaker
unit A is reversed and radiated to the outside of the cabinet 21. And a phase-reversal bath reflex
cabinet.
[0023]
Further, an acoustic signal is supplied to the speaker unit A via the amplifier to the input terminal
TA attached to the back plate 21b of the cabinet 21. The same as the acoustic signal applied to
the input terminal TA from the input terminal TB to the vibrator B. Electrical signals are provided
via a phase inverter and an amplifier.
Of course, if the winding directions of the voice coils of the speaker unit A and the vibrator B are
made opposite to each other, or if the magnetization directions of the magnets are made
opposite, the phase inversion circuit is unnecessary.
[0024]
In the configuration of FIG. 1 described above, when an acoustic signal is supplied to the input
terminals TA and TB, in the speaker unit A, the force of F = m0 α0 acts like the arrow in FIG. Is a
force of -F = mK.alpha.k, where m0 and mk are effective masses of the speaker unit A and the
vibrator B, and .alpha.0 and .alpha.k are accelerations of the diaphragm of the speaker unit A and
the vibrator B.
[0025]
As described above, when the speaker unit A and the vibrator B are driven, the force of -F 'acts on
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the force of the speaker unit A in the direction F by the reaction. For the force in the direction,
the force of F 'acts by the reaction.
[0026]
Now, assuming that the cabinet 21 and the baffle board 22 formed in a box shape are formed
into one body, the cabinet 21 receives a force in the left direction in FIG. 1 by the force of the
speaker unit A in the F direction. Since the vibrator B is given a driving force of −F opposite to
the driving force of the speaker, the cabinet 21 is pulled in the right direction in FIG. 1 and the
magnitude and direction of the force to move the cabinet 21 Is determined by the difference
between F and -F, and the cabinet 21 will not swing if the force F and the force -F are equal.
[0027]
In general, the force F = m 0 α 0 applied to the diaphragm in the case of a dynamic speaker is
determined by the following equation (1).
[0028]
Here, WE is an audio signal input applied to the speaker unit A or the exciter B, Bg is the
magnetic flux density of the gap of the magnetic circuit, Vv is the effective volume of the voice
coil, δ is the resistivity of the material of the voice coil, Q is the resonance sharpness of the
speaker unit A or the vibrator B, and the speaker unit A and the vibrator B cancel each other by
appropriately selecting the above-mentioned WE, Bg, Vv, δ, Q or m0, mk The force F = -F can be
selected under various conditions.
[0029]
Therefore, in order to set F = m0 α0 = mk αk, the equivalent mass m0 of the speaker unit A and
the equivalent mass mk of the exciter B should be the same or the magnetic flux density Bg of the
gap of the magnetic circuit of the speaker unit A and the excitation It is the easiest method to use
the same magnetic circuit or the like so that the magnetic flux density Bg of the gap of the
magnetic circuit of the vessel B becomes the same.
With such a configuration, it is possible to obtain a speaker device capable of preventing the
weakening of the sound radiation force due to the action and reaction force without swinging
even if the small and light cabinet 21 is not made of a heavy material.
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[0030]
As the speaker unit A of FIG. 1, the same general small-sized speaker unit A as used in FIG. 7 can
be used.
In addition, it is possible to use a magnetic shield type speaker in which a cancel magnet and a
shield cover that are oppositely magnetized to the magnetization direction of the magnet 1 are
provided on the back surface of the yoke 3.
[0031]
Moreover, an example of a structure of the vibrator B used for this invention is demonstrated
using FIG.2 and FIG.3.
In FIG. 2, the vibrator B of this example is formed of a disk-shaped plate material, and a stepped
portion is formed concentrically so as to surround the center pole 34 a of a columnar shape
embedded in the center and the center pole 34 a. A yoke 34 having an inverted T-shaped cross
section in which the magnet guide 34b is integrated, and a ring-shaped magnet 33 magnetized in
the thickness direction and having an inner diameter fitted and joined to the magnet guide 34b
of the yoke 34. A magnetic circuit of a metal part is constituted by a ring-shaped plate 31 bonded
to the upper surface of the magnet 33 with an adhesive or the like and a funnel-shaped frame 37
made of steel or the like fixed on the plate 31.
[0032]
A state in which a spacer such as kraft paper is wound around the inner periphery of the voice
coil bobbin 38 in order to insert the voice coil 38a wound around the voice coil bobbin 38 in the
concentric magnetic gap 47 between the center pole 34a and the plate 31 Then, the voice coil
bobbin 38 is inserted into the center pole 34 a from the upper side, and the position of the voice
coil 38 a is set so as to be disposed in the magnetic gap 47.
[0033]
A corrugated concentric damper 39 is bonded between the outer diameter of the upper end of
the voice coil bobbin 38 and the bottom of the frame 37 with an adhesive or the like, and the
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inner diameter of the diaphragm 7B has a plurality of vents 48 formed in a funnel shape. The
part is fitted and joined to the outer diameter of the upper end of the voice coil bobbin 38, and
the largest diameter part of the diaphragm 7B is joined to the largest diameter opening of the
frame 37 via the arrow 42.
[0034]
After the adhesive is dried, the spacer inserted into the inner diameter of the voice coil bobbin 38
is removed, and a cap 44 having a plurality of vent holes 48 formed therein is joined to the upper
surface of the voice coil bobbin 38.
[0035]
A lead wire is drawn from the voice coil 38a, connected to the input terminal 45 through the
tinsel wire 46, and an electrical signal is supplied to the voice coil 38a through the input terminal
45.
Although the case where the magnet 33 magnetized in advance is assembled has been described
above, the non-magnetized magnet 33 may be magnetized at the final assembly stage.
In this case, the direction of magnetization of the magnet of the speaker unit A is opposite to that
of the magnet, or the winding direction of the voice coil 38a is opposite to that of the speaker
unit A.
Further, in the case of the one magnetized or wound in the same direction, the reverse drive
signal may be supplied.
As a matter of course, the vibrator B may be used which is magnetized and wound in the same
direction as the speaker unit.
[0036]
FIG. 3 shows another example of the configuration of the vibrator of the present invention, and
the parts corresponding to those in FIG.
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[0037]
In FIG. 3, the configuration up to the magnetic circuit and the lower damper 39a having air
permeability is the same as that of FIG. 2, but air permeable formed with a cloth between the
maximum outer diameter opening of the frame 37 and the outer diameter of the voice coil
bobbin 38 A good upper damper 39b is provided.
The outer diameter portion of the upper damper 39b is fixed to the frame 37 via the arrow 42,
and the upper damper 39a and the input terminal 37 are connected via the tinsel wire 46, and
the tinsel wire and the voice coil 38a are connected. .
In this configuration, the upper damper 39b constitutes the diaphragm 7B.
Also, the cap 44 which is covered on the upper surface of the voice coil bobbin 38 is also
selected from a material having good breathability such as cloth.
[0038]
FIGS. 4 to 6 show the configuration of another speaker device according to this embodiment, and
in FIG. 4, a vibrator B in which equivalent weights and the like of the magnetic circuit and the
vibration system are equal to the speaker unit A described in FIG. A protrusion 27 is provided on
the baffle board 22 opposite to the diaphragm 7B to which the vibrator B is attached. The
protrusion 27 is mounted on the baffle board 22 on the upper side of the speaker unit A, and
between the diaphragm 7B and the protrusion 27 A space 28 is formed.
The stiffness of the air in the space portion 28 is configured so that the low resonance frequency
of the speaker unit A becomes equal to the air stiffness in the cabinet 21. Of course, the vibrator
B shown in FIG. 3 may be attached in the configuration of FIG. 4, and the vibrator B and the
speaker unit A are supplied with electric signals of opposite phase.
[0039]
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FIG. 5 shows a speaker device showing still another configuration of the present invention. In
FIG. 5, the speaker unit A is fixed to face the mounting hole 24 of the speaker of the baffle board
22 and the excitation shown in FIG. The unit B is fixed to the back plate 21b of the cabinet 21 so
that the yokes on the back of the speaker unit A face each other. In this case, the exciter B may
have the same magnetization direction of the speaker unit A and the magnet 33 and the winding
direction of the voice coil 38a, and the electric signals supplied to the input terminals TA and TB
also have the same acoustic signal in phase. Is supplied.
[0040]
Also in this configuration, the space portion 28 is formed between the diaphragm 7B of the
vibrator B or the upper damper 39b and the rear plate 21b of the cabinet 21, and the stiffness of
the space portion 28 is adjusted to the stiffness of the air in the cabinet 21. It will be done in the
same way.
[0041]
In the configuration of FIG. 5 and FIG. 6 described later, since the speaker unit A and the exciter
B may have the same magnetic force of the magnetic circuit and the magnetic flux direction of
the air gap, the equivalent mass of the vibration system and the support system can be easily
matched The lowest resonance frequency of the vibrator B is easy to match, and the vibrator B
has a canceling action over a wide frequency range, and a speaker device with good sound
quality can be obtained, particularly in a low band with radiation power.
[0042]
FIG. 6 shows still another configuration of the present invention, in which, when the vibrator B is
attached to the back of the cabinet 21, it is fixed at a position facing the opening of the duct 32
constituting the phase inversion cabinet. A protrusion 27 is provided at a position opposite to the
opening of the duct 32 of the back plate 21b, and the exciter B is fixed via the frame of the
exciter B so as to face the protrusion 27. A space 28 is formed between the plate 7B and the
projection 27 to adjust the stiffness of the diaphragm 7B of the vibrator B.
When the minimum resonance frequency of the support system of the exciter B is matched to the
resonance frequency of the duct 32 while the swing of the cabinet 21 can be prevented by the
cancel effect due to the action and reaction between the exciter B and the speaker unit A, the
duct 32 Since it is possible to cancel the reaction of the low-frequency sound emission from the
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vibration absorber B, it is possible to perform stronger bass radiation from the opening of the
duct 32.
[0043]
According to the present invention, it is possible to increase the radiation power of the low range
of the speaker unit, and to obtain a speaker device capable of improving the sound quality
without swinging the cabinet of the small and light speaker device.
[0044]
Brief description of the drawings
[0045]
1 is a side sectional view of the speaker device of the present invention.
[0046]
2 is a cross-sectional view of a vibrator used for the speaker device of the present invention.
[0047]
3 is a cross-sectional view of another vibrator used for the speaker device of the present
invention.
[0048]
4 is another side sectional view (I) of the speaker device of the present invention.
[0049]
5 is another side sectional view (II) of the speaker device of the present invention.
[0050]
6 is another side sectional view (III) of the speaker device of the present invention.
[0051]
7 is a partial sectional view of the conventional speaker device.
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[0052]
Explanation of sign
[0053]
A: Speaker unit, B: Vibrator, 7A, 7B: Diaphragm, 21: Cabinet, 22: Baffle board, 48: Vent
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