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JP2012070148

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DESCRIPTION JP2012070148
PROBLEM TO BE SOLVED: To provide a speaker with a double diaphragm structure in which a
second diaphragm and a bobbin of a voice coil are connected even when the first diaphragm on
the front side constituting a vibration system has a surface material including a woven fabric. The
speaker with high rigidity of the vibration system and excellent in reproduction sound quality
with few peak dips on sound pressure frequency characteristics is provided. SOLUTION: The
speaker has a substantially cone-shaped first diaphragm disposed on the front side, and a
substantially cone disposed on the back side of the first diaphragm and connected to the outer
periphery of the first diaphragm on the outer peripheral side thereof. And a voice coil including a
substantially cylindrical bobbin in which the first and second diaphragms are separated and
connected to each other, and the second diaphragm is connected to the bobbin And a plurality of
engaging portions extending radially outward from the inner peripheral portion of the base and
engaging with the engaging recessed portions of the first diaphragm at the outer peripheral end
thereof. The engaging portions of the adjacent second diaphragms are separated from each other
and respectively engaged with the engaging recesses of the first diaphragm. [Selected figure]
Figure 4
スピーカー
[0001]
The present invention relates to a speaker that uses a diaphragm that is lightweight, has high
rigidity, and has a wide piston vibration zone, and in particular, a first diaphragm disposed on the
front side that emits sound waves, and a speaker that is disposed on the back side of the first
diaphragm. A speaker having a speaker vibrating system of a double diaphragm structure
including a second vibrating plate and a bobbin of a voice coil connected to the first vibrating
plate and the second vibrating plate.
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[0002]
In the speaker, an assembly structure in which an inner peripheral end of a speaker diaphragm
(in particular, a cone type diaphragm) is adhered with an adhesive to a cylindrical side surface of
a cylindrical voice coil bobbin is often used.
Some conventional speakers attempt to reduce the number of assembly steps by devising this
assembly structure. In addition, in a speaker provided with a cone-shaped diaphragm or a domeshaped diaphragm, a double vibration that improves the strength of the speaker vibration system
by providing a cone-shaped diaphragm behind the diaphragm exposed to the front side. Board
structure may be adopted.
[0003]
Conventionally, for example, in a speaker in which a central portion of a diaphragm is coupled to
a voice coil embedded in a magnetic gap of a magnetic circuit, the diaphragm has two or more
sheets in which one of a half apex angle and a curvature is different. There is a speaker
characterized in that it is configured using a cone of U.S. Pat. Moreover, as a speaker of the
double diaphragm structure according to the applicant of the present invention, the respective
outer peripheral portions of two cone-shaped diaphragm base materials having different half
apex angles are adhered to each other, and the inner periphery of a common edge member The
respective inner peripheral portions of the diaphragm base are connected to the common voice
coil bobbin with a gap therebetween, and the core material is inserted in the gap between the
two diaphragm bases. There is a speaker characterized in that a diaphragm having a filled
structure is held by a frame through the edge (Patent Document 2).
[0004]
Further, in the inverted dome type speaker in which the shape of the diaphragm is a front
longitudinal cross section and the curved surface protrudes downward in a dome shape, the
diaphragm 1 is formed by injection molding mainly made of thermoplastic resin and concentric
on the back surface of the diaphragm 1 A plurality of ring-shaped ribs 15a, 15b, 15c, 15d are
provided, and the voice coil bobbin 2 is fixed to the diaphragm 1 with one of the ribs 15 as a
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guide, and the voice coil bobbin 2 There is a speaker in which a ring-shaped throat 22 is
disposed between the two and the other rib of the rib group 15 (Patent Document 3). Also, attach
the sub-cone vibrator to the outer periphery of the voice coil bobbin, which is erected at the
center bottom of the speaker frame, and secure at least the distal end widening of this sub-cone
vibrator to the flat diaphragm, In the flat speaker device elastically held by the speaker frame, the
sub-cone vibrating body is constituted by two or more pieces, and the tip spread portion of each
piece of the sub-cone vibrating body is a vibration of the flat plate-like diaphragm There is a flat
type speaker device characterized in that it is fixed to a part of a joint circle portion of the above
(Japanese Patent Application Laid-Open No. 2000-147118).
[0005]
Further, a speaker diaphragm which does not have a dual diaphragm structure according to the
applicant of the present invention has a first diaphragm portion 5, a second diaphragm portion 6
integrally formed with the first diaphragm portion 5, and a first vibration. The first diaphragm
portion 5 and the second diaphragm portion 6 are provided with a mounting portion 7 which is
provided on the back side of the joint portion between the plate portion 5 and the second
diaphragm portion 6 so as to be protruded and to which one end of the voice coil bobbin is
attached. The base material is impregnated with a thermosetting resin, and the mounting portion
7 is formed by curing the thermosetting resin (Patent Document 5). There is also a speaker
diaphragm having a base and a surface material disposed on one side of the base and containing
a woven fabric of polyethylene naphthalate fibers (Patent Document 6). These speaker
diaphragms reduce the transmission loss of the driving force from the voice coil bobbin, and
particularly in the latter case, realize a speaker diaphragm excellent in the balance between the
Young's modulus and the internal loss. Can improve the S / N ratio.
[0006]
JP-A-63-155900 (FIG. 1) JP-A-62-68394 (FIGS. 1 to 3) JP-A-9-247791 (FIG. 3) JP-A-59-171399
(FIGS. 4-8) Patent No. 3846497 (FIGS. 1-4) JP 2007-259261 A
[0007]
However, the speaker vibration system of the conventional double diaphragm structure is not
sufficient.
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With the first diaphragm on the front side and the second diaphragm on the back side, the
speaker vibration system with a double diaphragm structure whose weight tends to be heavy is
generally used to enhance the reproduction efficiency of the speaker. It is necessary to reduce
the weight. In the speaker vibration system having a double diaphragm structure, if rigidity is
insufficient due to weight reduction unless the first diaphragm on the front side and the second
diaphragm on the rear side are respectively designed optimally, the respective diaphragms There
is a problem that the influence of the divided vibration mode in the above appears at a low
frequency. That is, the speaker vibration system of the double diaphragm structure in which the
first diaphragm and the second diaphragm are combined including the bobbin of the voice coil
has a peak on the sound pressure frequency characteristic when the rigidity as the coupled
structure becomes low. -There is a problem that the dip becomes large and the piston vibration
area becomes narrow, which may cause the deterioration of the reproduction sound quality. In
particular, when the first diaphragm on the front side has a surface material including a woven
fabric, the material anisotropy of the woven fabric being strong in the direction of the warp and
weft and weak in the 45-degree angular direction between them. As a result, there is a problem
that the influence of the divided vibration mode of the first diaphragm becomes large.
[0008]
The present invention has been made to solve the problems of the prior art described above, and
the object thereof is that the first diaphragm on the front side constituting the vibration system
has a surface material including a woven fabric. Even if the speaker vibration system of the
double diaphragm structure in which the first diaphragm, the second diaphragm, and the bobbin
of the voice coil are connected, the rigidity of the speaker vibration system is high, and the
reproduction sound quality has few peak dips on the sound pressure frequency characteristics.
To provide excellent speakers.
[0009]
The speaker according to the present invention includes a substantially cone-shaped first
diaphragm disposed on the front side for emitting a sound wave, and a diaphragm disposed on
the back side of the first diaphragm and connected to the outer periphery of the first diaphragm
on the outer circumferential side And a voice coil including a substantially cylindrical bobbin in
which inner peripheral sides of the first diaphragm and the second diaphragm are respectively
separated and connected, and the first diaphragm is An engagement ridge portion extended so as
to be folded back from the outer peripheral end of the substantially cone-shaped base, defining a
convex ridge on the front side and defining an engagement recess on the rear side of the ridge,
and the base A second diaphragm having a surface member including a woven fabric made of
plain weave, warp (weather) weave, satin (latin) weave including warps and wefts bonded to the
front side of the second diaphragm; A base including an inner peripheral portion connected to
the outer peripheral end of the base and extending radially outward from the inner peripheral
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portion of the base And a plurality of engaging portions engaged with the engaging recessed
portions of the first diaphragm, and the engaging portions of the adjacent second vibrating plates
are separated from each other and respectively engaged with the engaging recessed portions of
the first vibrating plate Do.
[0010]
Preferably, in the speaker according to the present invention, the engagement portion of the
second diaphragm is formed in four directions in rotational symmetry with respect to the center
point of the base, and the engagement portion and center point of each second diaphragm are
The first diaphragm and the second diaphragm are arranged such that the straight line
connecting them deviates about 45 degrees with the direction of the warp of the woven fabric
constituting the surface material of the first diaphragm, or with the direction of the weft. .
[0011]
Preferably, in the speaker of the present invention, the first diaphragm is formed by
impregnating a substrate containing a woven or non-woven fabric made of fibers with a
thermosetting resin containing an unsaturated polyester resin, or a paper The second diaphragm
has a base using a paper material formed by making paper and forming fibers as a base, and the
second diaphragm has a base using a paper material made by forming paper fibers and forming a
paper.
[0012]
Preferably, in the speaker according to the present invention, the first diaphragm is connected to
the inner peripheral side of the substantially cone-shaped base with the connecting portion
connected to the end of the bobbin, and the central portion covering the inner peripheral side of
the connecting portion. , Are formed integrally with the base.
[0013]
Preferably, in the speaker according to the present invention, the frame is connected to a damper
in which an inner peripheral end is connected to a bobbin of a voice coil, a frame in which an
outer peripheral part of an edge and an outer peripheral end of the damper are connected, And a
magnetic circuit having a magnetic air gap in which the coil of the coil is disposed.
[0014]
Hereinafter, the operation of the present invention will be described.
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[0015]
The speaker according to the present invention includes a substantially cone-shaped first
diaphragm disposed on the front side for emitting a sound wave, and a diaphragm disposed on
the back side of the first diaphragm and connected to the outer periphery of the first diaphragm
on the outer circumferential side And a voice coil including a substantially cylindrical bobbin in
which inner peripheral sides of the first diaphragm and the second diaphragm are respectively
separated and connected.
Preferably, in the speaker according to the present invention, the outer periphery coupled to the
frame, the inner periphery coupled to the outer periphery of the first diaphragm or the second
diaphragm, and the outer periphery and the inner periphery are defined. A frame having an edge
having a supported movable portion, a damper whose inner peripheral end is connected to the
bobbin of the voice coil, a frame where the outer peripheral portion of the edge and the outer
peripheral end of the damper are connected, And a magnetic circuit having a magnetic air gap in
which a coil of the voice coil is disposed.
Therefore, the speaker of the present invention is an electrodynamic speaker having a speaker
vibration system with a double diaphragm structure.
[0016]
The first diaphragm is extended so as to be folded back from the outer peripheral end thereof, an
engagement ridge defining a convex ridge on the front side and defining an engagement recess
on the back of the ridge, and It is bonded to the front side of the substrate, and has a surface
material including a woven fabric made of plain weave including warp and weft, twill weave, and
satin weave.
The engagement flange portion of the first diaphragm enhances the strength on the outer
peripheral side of the first diaphragm and engages with the annular recess of the edge.
The second diaphragm is a base including an inner peripheral portion connected to the bobbin,
extends radially outward from the inner peripheral portion of the base, and engages with the
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engagement concave portion of the first diaphragm at an outer peripheral end thereof And a
plurality of engaging portions, wherein the first diaphragm and the second diaphragm are
connected by the first adhesive applied thereto.
Therefore, the first diaphragm and the second diaphragm are separated from each other on the
inner peripheral side thereof and coupled to the bobbin of the substantially cylindrical voice coil,
and thus constitute a speaker vibration system that is a strong structure having a substantially
triangular cross section. Do.
The first diaphragm is formed integrally with the base on the inner peripheral side of the
substantially cone-shaped base, with the connecting part connected to the end of the bobbin and
the central part covering the inner peripheral side of the connecting part. It may be in the form
of a dome, or in the form of a cone integrated with a dust cap.
[0017]
Specifically, the first diaphragm is a speaker diaphragm in which a base is formed by
impregnating a base material including a woven or non-woven fabric made of fibers with a
thermosetting resin containing an unsaturated polyester resin, plain weave, A surface material
including a woven fabric of silk fibers or polyethylene naphthalate fibers, which are made of
either twill (shallow) or tweezers (tweezers), is further provided on the front side.
The second diaphragm is a speaker diaphragm in which a base having a paper material formed
by paper-making of paper fibers as a base material is molded.
[0018]
In the speaker vibrating system having the double diaphragm structure according to the present
invention, the plurality of engaging portions of the outer peripheral edge portion of the second
diaphragm defined as a portion to which the inner peripheral portion of the edge is connected is
between the first diaphragm and the plurality of engaging portions In addition, a separation
space is formed in which the distance separating from the engagement portion of the second
diaphragm toward the inner circumferential side becomes large. By providing this separated
space, the outer peripheral side of the first diaphragm that emits sound waves on the front side is
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reinforced by the outer peripheral side of the more rigid second diaphragm, which has a higher
frequency at which divided vibration occurs from the first diaphragm. As a result, it is possible to
push up the frequency of the mode in which the outer peripheral side starts divided vibration to
a higher frequency, and to expand the piston vibration region.
[0019]
Here, since the second diaphragm is extended radially outward from the inner peripheral portion
of the base and has a plurality of engaging portions engaged with the engaging concave portions
of the first diaphragm at the outer peripheral end portion, The engaging portions of the matching
second diaphragms are separated from each other and respectively engage with the engaging
recesses of the first diaphragm. That is, since the second diaphragm is cut out so that adjacent
engagement parts are separated from each other, the second diaphragm is substantially reduced
in weight by eliminating the space between the engagement parts. The area of the diaphragm of
the second diaphragm can be reduced to reduce the radiation noise from the second diaphragm.
Further, by providing the plurality of engaging portions at the outer peripheral end of the second
diaphragm, it is possible to give the rigidity of the second diaphragm any anisotropy. Preferably,
in the case where the engagement portion of the second diaphragm is formed in four directions
in rotational symmetry with respect to the center point of the base, an oblique 45 degree
between the engagement portions of the second diaphragm is There are gaps in four directions
in the angular direction.
[0020]
In the speaker according to the present invention, the straight line connecting the respective
engagement parts of the second diaphragm and the center point is the direction of the warp of
the woven fabric constituting the surface material of the first diaphragm, or the direction of the
weft, and The first diaphragm and the second diaphragm may be disposed so as to be shifted by
45 degrees. When the first diaphragm on the front side has a surface material including a woven
fabric, the material anisotropy of the woven fabric is strong in the direction of the warp and weft,
and weak in the 45-degree angle direction between them. Even when the influence of the divided
vibration mode of the first diaphragm becomes large, the first diaphragm and the first diaphragm
are arranged so that the direction in which the rigidity of the first diaphragm is weak matches
the direction in which the rigidity of the second diaphragm is strong. By arranging the two
diaphragms, it is possible to realize a speaker excellent in reproduction sound quality with less
peak-dip on the sound pressure frequency characteristic by suppressing divisional vibration
mutually.
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[0021]
The speaker according to the present invention can provide a speaker excellent in reproduction
sound quality, having high rigidity of a speaker vibration system having a double diaphragm
structure and less peak-dip on sound pressure frequency characteristics.
[0022]
It is a figure explaining the speaker 1 by preferable embodiment of this invention.
(Example 1) It is a principal part enlarged view explaining the speaker vibration system of the
speaker 1 of this invention. (Example 1) It is a top view explaining the 1st diaphragm 5 of the
speaker 1 of this invention. (Example 1) It is a perspective view explaining the speaker vibration
system of the speaker 1 of the Example of this invention. (Example 1) It is a figure explaining the
vibration mode of the speaker 1 of this invention, and the speaker 100 of a comparative example.
(Example 1, Comparative Example 1) It is a graph explaining the acoustic characteristic of the
speaker 1 of this invention and the speaker 100 of a comparative example. (Example 1,
Comparative Example 1)
[0023]
Hereinafter, although the speaker by the preferred embodiment of the present invention is
explained, the present invention is not limited to these embodiments.
[0024]
FIG. 1 is a schematic cross-sectional view of a speaker 1 according to a preferred embodiment of
the present invention.
Further, FIG. 2 is an enlarged view of a main part for explaining a speaker vibration system of the
speaker 1, and is a cross-sectional view in which an X portion illustrated in FIG. FIG. 3 is a plan
view for explaining the first diaphragm 5 constituting the speaker vibration system of the
speaker 1, and FIG. 4 is a perspective view for explaining the speaker vibration system of the
speaker 1. In addition, as described later, a part of the structure, an internal structure, and the
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like of the speaker 1 are omitted. Further, in the speaker 1, the upper side of the speaker
diaphragm 5 as the first diaphragm to be exposed is the front side, and the lower side to which
the magnetic circuit 10 is attached is the rear side.
[0025]
The speaker 1 is an electrodynamic speaker having a caliber of about 15 cm and provided with a
bullet-like equalizer 9, and is provided with a substantially cone-shaped first diaphragm 5
disposed on the front side for emitting sound waves, and a first diaphragm A substantially coneshaped second diaphragm 6 which is disposed on the back side of the fifth side and is connected
to the outer circumferential side of the first diaphragm 5 on the outer circumferential side, and
the inner circumferential sides of the first diaphragm 5 and the second diaphragm 6 A voice coil
bobbin 2 having a substantially cylindrical shape, which is separated and connected, and a voice
coil 3 wound around the lower end portion of the voice coil bobbin 2 constitute a speaker
vibration system having a double diaphragm structure. The voice coil bobbin 2 and the voice coil
3 are disposed in the magnetic air gap of the magnetic circuit 10 fixed to the frame 8 and
displace in the magnetic air gap according to the input signal so that the speaker of the double
diaphragm structure of the speaker 1 Drive the vibration system. Further, the speaker vibration
system of the double diaphragm structure of the speaker 1 is supported so as to be vibrated in
the vertical direction as illustrated by the damper 4 and the edge 7 whose outer peripheral side
is fixed to the frame 8.
[0026]
The voice coil bobbin 2 is made of, for example, aluminum having a material thickness of 0.05
mm, the voice coil 3 is wound around the lower end thereof, and the reinforcing paper is wound
around the outer curved surface where the voice coil 3 is not wound. In general, they are formed
in a cylindrical shape having a diameter of about 39.0 mm. The voice coil bobbin 2 may also be
formed of polyimide film, duralumin, silter, capton or the like. A tinsel wire (not shown) is
soldered and fixed to the voice coil 3, and the other end of the tinsel wire is fixed so as to be
conductive to a terminal (not shown) fixed to the frame 8. Voice signal current is supplied to the
voice coil 3 through these terminals and the tinsel wire.
[0027]
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The inner diameter end of the damper 4 is connected to the outer curved surface of the voice coil
bobbin 2 by an adhesive. The outer diameter end of the damper 4 is adhesively fixed to the
damper fixing portion of the frame 8. The damper 4 may be an annular ring-shaped corrugation
damper which is formed by impregnating a resin such as a phenol resin with a flexible fiber
woven fabric as a base material, and is formed of another material. It is also good. For example, it
may be a butterfly damper which has an arm connecting the inner ring and the outer ring and is
formed of metal or resin. The frame 8 is a frame of aluminum die-cast formed in a basket shape,
and is connected to the magnetic circuit 10 by a plurality of screws. The frame 8 may be an iron
plate frame press-formed into a basket shape corresponding to the speaker vibration system
having a double diaphragm structure.
[0028]
The magnetic circuit 10 has an annular top plate 11 fixed to the frame 8 and a pole which has a
cylindrical pole and a center pole and a flat underplate inserted in a circular hole formed at the
center of the top plate 11. 12 and an annular magnet 13. The top plate 11 and the pole 12 form
a circular magnetic air gap having a uniform width. The magnet 13 is bonded so as to be held
between the top plate 11 and the under plate of the pole 12. The magnet 13 of the present
embodiment is a ferrite based magnet, and may be an Nd-Fe-B based rare earth magnet having a
larger residual magnetization and coercivity, and having a smaller volume or a stronger
coercivity. In the magnetic circuit 10 of the present embodiment, the cancel magnet 14 is
magnetized and coupled on the back side of the underplate of the pole 12 so as to have magnetic
polarity in the reverse direction to the magnet 13, and the back side of the cancel magnet 14.
And a cover 15 magnetically shielded to cover the entire magnetic circuit 10.
[0029]
The equalizer 9 is a shell-shaped member formed of an alloy containing aluminum in the present
embodiment, and is formed on the center pole of the pole 12 of the magnetic circuit 10 so that
the pointed end side protrudes from the neck portion of the first diaphragm 5. It is connected
and fixed. The equalizer 9 fills in the cylindrical internal space formed by the voice coil bobbin 2
and a part of the space surrounded by the first diaphragm 5 having a substantially cone shape,
eliminates air occupying these spaces, and prepares directivity characteristics. Flatten the sound
pressure frequency characteristics. The equalizer 9 connected to the magnetic circuit 10 is
preferably formed of a nonmagnetic member such as brass or resin.
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[0030]
The first diaphragm 5 is a diaphragm exposed on the front side when the speaker 1 having the
speaker vibration system having a double diaphragm structure is viewed from the front, and the
first diaphragm 5 is substantially defined by a curved line whose cross-sectional shape is
smoothly continuous. The diaphragm is a cone-shaped diaphragm, and has a substantially coneshaped diaphragm portion 5a and an engaging flange 5b extended so as to be folded back from
the outer peripheral end. The substantially cone-shaped diaphragm portion 5a has an inner
diameter of about 39.5 mm in diameter, an outer diameter of about 113.5 mm in diameter, and a
height of about 26.8 mm. The engagement collar 5b having a length of about 1.5 mm defines a
convex ridge 5c on the front side and an engagement recess 5d on the back of the ridge 5c, as
shown in FIG. Do. The inner diameter end of the first diaphragm 5 is connected to the outer
curved surface of the voice coil bobbin 2 by an acrylic adhesive.
[0031]
The first diaphragm 5 of the present embodiment is a base formed by impregnating a
thermosetting resin with a base material which is a laminate including a woven fabric layer or a
non-woven fabric layer made of inorganic fibers or natural fibers (diaphragm portion 5a , An
engagement flange 5b, a ridge 5c, and an engagement recess 5d. And a facing 5e adhered to the
front side of the base. Specifically, the substrate is obtained by laminating two layers of nonwoven fabric of Technora fiber, impregnating the unsaturated polyester resin, and hot pressing.
Unsaturated polyester has a high curing rate and a low curing temperature, so that the substrate
can be produced by short-time hot press molding.
[0032]
In addition, the surface material 5e is obtained by applying a thermoplastic adhesive to this
substrate and drying it, the woven fabric of PEN fibers of plain weave is put along, and these are
integrated by heat press forming. The woven fabric of plain weave PEN fibers forming the facing
5e has warps and wefts, as shown in the plan view of FIG. 3 where the facing 5e of the first
diaphragm 5 is exposed. Accordingly, the woven fabric of the plain weave PEN fibers is in a
relationship in which the PEN fibers have a weave direction substantially perpendicular to the
longitudinal direction and the transverse direction, so the direction along the weave direction
(warp and weft directions: FIG. 3 A difference in strength occurs between the dx1 direction and
the dx2 direction) and the direction not along the weaving direction (45-degree oblique angle
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direction between warp and weft: dy1 direction, dy2 direction in FIG. 3). As a result, the first
diaphragm 5 integrated with the surface material 5e containing plain woven PEN fibers is strong
in the direction of the warp and weft, and in the oblique 45-degree angle direction between the
direction of the warp and weft. Is weak, it will exert material anisotropy of the woven fabric.
[0033]
The second diaphragm 6 is a diaphragm that hides on the rear side when the speaker 1 having
the double diaphragm structure and the speaker vibration system is viewed from the front, and
the first diaphragm 5 has a smoothly continuous sectional shape. Is a substantially cone-shaped
diaphragm defined by a different R curve and a straight line. The second diaphragm 6 has a
paper base formed by papermaking, and the substantially cone-shaped diaphragm portion 6a has
an inner diameter of about 39.5 mm and an outer diameter of about 111. It is 5 mm and its
height is about 31.2 mm. Further, as illustrated in FIG. 4, the second diaphragm 6 is a diaphragm
having a base cut out in four directions in the radial direction viewed from the center, and the
four diaphragm portions 6 a in the form of a segment are , And radially outward from the inner
circumferential portion 6c. The inner peripheral portion 6 c of the second diaphragm 6 is
connected to the outer curved surface of the voice coil bobbin 2 by an acrylic adhesive so as to
be separated from the inner diameter end of the first diaphragm 5. The second diaphragm 6 has
four engaging portions 6 b engaged with the engaging recesses 5 d of the first diaphragm 5 at
the outer peripheral end of the four diaphragm portions 6 a.
[0034]
As a result, since the second diaphragm 6 is cut out so that the adjacent engaging portions 6b are
separated from each other, the through holes 6d are defined in four directions between the
engaging portions 6b. Each of the four diaphragm portions 6a and the engagement portion 6b of
the second diaphragm 6 are formed in four directions in rotational symmetry with respect to the
central point, and are disposed at intervals of 90 ° in the circumferential direction, Each has a
width of only about 30 °. Therefore, between the engaging portions 6b separated by the
through hole 6d corresponds to about 60 ° in the circumferential direction, and the second
diaphragm 6 is reduced in weight by defining the through hole 6d. There is. In addition, since the
second diaphragm 6 is cut out so that the adjacent engagement parts 6b are separated on the
outer peripheral end side, the directions of the four diaphragm parts 6a and the engagement
parts 6b (see FIG. It has an anisotropy of being strong in the dz1 direction (corresponding to the
dy1 direction), dz2 direction (corresponding to the dy2 direction), and weak in the four through
holes 6d.
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[0035]
The edge 7 is an annular shape or a ring-shaped corrugation edge that vibratably supports a
speaker vibration system having a double diaphragm structure, and an outer peripheral portion 7
a adhesively fixed to an edge fixing portion of the frame 8; An inner peripheral portion 7b
connected to the outer peripheral side of the second diaphragm 6 from the back side, a movable
support portion 7c forming a corrugation between the outer peripheral portion 7a and the inner
peripheral portion 7b, and a corrugation of the movable support portion 7c And an annular
recess 7d engaged with the engagement flange 5b of the first diaphragm 5 from the front side on
the inner peripheral side. The edge 7 of this embodiment is formed by pressure heating a suedelike artificial leather made of ultrafine fibers of polyester having flexibility, and a paper gasket 7e
is adhered to the front side of the outer peripheral portion 7a. ing. The support movable portion
7c of the edge 7 of the present embodiment has a corrugation in which the height of the peak
portion which is convex forward becomes smaller as going from the outer peripheral side to the
inner peripheral side.
[0036]
As shown in FIG. 2, at the outer peripheral end of the diaphragm portion 5a of the first
diaphragm 5, an engagement collar 5b including a base material or a thermosetting resin is
formed. The engagement flange portion 5b functions as a rib that reinforces the diaphragm
portion 5a at the outer peripheral end of the diaphragm portion 5a to enhance the strength on
the outer peripheral side, and on the opposite side of the diaphragm portion 5a to the
substantially cone shape. Since it is formed as a folded ridge portion, a convex ridge portion 5c is
defined on the front side, and an engagement recess 5d is defined on the back side of the ridge
portion 5c. In the case of the speaker 1 of the present embodiment, the second diaphragm 6 has,
at its outer peripheral end, four engaging portions 6b which engage with the engaging recesses
5d of the first diaphragm 5, and Since the inner peripheral portion 7b of the edge 7 is adhesively
fixed, the engagement flange 5b of the first diaphragm 5 engages with the annular recess 7d of
the support movable portion 7c formed by the corrugation of the edge 7.
[0037]
That is, in the speaker 1 of the present embodiment, in the step of bonding the outer peripheral
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end of the first diaphragm 5 to the vibration system formed by the second diaphragm 6 and the
edge 7, the engagement flange 5 b of the first diaphragm 5 is Can be bonded to the voice coil
bobbin 2 and the second diaphragm 6 without tilting the first diaphragm 5 by engaging the
annular recess 5 d formed by the corrugation of the edge 7. The second vibrating plate 6 has
four engaging portions 6b at its outer peripheral end engaged with the engaging recesses 5d of
the first vibrating plate 5. Therefore, when the first adhesive Ad1 is applied thereto, the first
vibration is generated. The plate 5 and the second diaphragm 6 are connected. As shown in FIG.
1, the first diaphragm 5 and the second diaphragm 6 are separated from each other at their inner
peripheral sides and connected to the voice coil bobbin 2 having a substantially cylindrical shape,
so that a strong structure having a substantially triangular cross section Constitute a speaker
vibration system having a double diaphragm structure.
[0038]
Further, in the speaker vibration system of the double diaphragm structure of the speaker 1 of
the present embodiment, the outer peripheral edge portion of the second diaphragm 6 defined as
a portion to which the inner peripheral portion 7 b of the edge 7 is connected is the first
diaphragm Between the space 5 and the space 5, a separation space Y is formed in which the
distance separating from the engagement portion 6b of the second diaphragm 6 toward the inner
circumferential side becomes large. The separation space Y is a triangular space having a sharp
cross section defined between the back surface of the first diaphragm 5 and the front surface of
the second diaphragm 6 as illustrated in FIG. By providing this separated space Y, the outer
peripheral side of the second diaphragm 6, which is higher in frequency at which the outer
peripheral side of the first diaphragm 5, which radiates sound waves on the front side, is divided
by the first diaphragm 5, is reinforced. Structure is realized.
[0039]
In the case of the present embodiment, the first adhesive Ad1 applied to the engagement recess
5d of the first diaphragm 5 and the engagement portion 6b of the second diaphragm 6 engaged
therewith is a rubber adhesive. The adhesive has a relatively high Young's modulus after curing
and a high hardness and hardness, and an internal loss is small. Further, in the case of the
present embodiment, the second adhesive Ad2 different from the first adhesive Ad1 is applied to
the separation space Y defined between the first diaphragm 5 and the second diaphragm 6 Be
filled. The second adhesive Ad2 is an acrylic resin emulsion adhesive, and is an adhesive having a
relatively small Young's modulus after curing of the adhesive, a small hardness and softness, and
a large internal loss. For example, in the case of the present example, the first adhesive Ad1 has a
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Young's modulus of 7.3E + 8 Pa after the adhesive is cured, and an internal loss of 0.161 after
the adhesive is cured. Hardness is about 27 points with a type A durometer conforming to K
6253. On the other hand, the second adhesive Ad2 has a Young's modulus of 6.5 E + 7 Pa after
the adhesive is cured, and an internal loss of 0.30 and a hardness of about 8 points after the
adhesive is cured. . That is, the first adhesive Ad1 is a harder adhesive than the second adhesive
Ad2. The first adhesive Ad1 and the second adhesive Ad2 are preferably separately applied so as
not to be mixed.
[0040]
By the way, as illustrated in FIG. 4, in the speaker vibration system of the double diaphragm
structure of the speaker 1 of the present embodiment, the surface material 5 e including the
woven fabric of the plain weave PEN fiber is anisotropic A first diaphragm 5, and a notched
second diaphragm 6 having anisotropy that is strong in the direction of the four diaphragm
portions 6a and the engaging portion 6b and weak in the direction of the four through holes 6d ,
Are arranged in a mutually reinforcing relationship. That is, since the four diaphragm portions 6a
and the engaging portions 6b of the second diaphragm 6 are formed in four directions (dz1
direction, dz2 direction in FIG. 4) in rotational symmetry with respect to the center point of the
base, The direction of the warp or weft of the woven fabric forming the surface member 5e of the
first diaphragm 5 (the dx1 direction, the dx2 direction in FIG. 3) The first diaphragm 5 and the
second diaphragm 6 are disposed so as to be deviated by about 45 degrees. In other words, the
straight line connecting the engagement portion 6 b of the second diaphragm 6 and the center
point is 45 degrees diagonally between the warp and weft directions of the woven fabric
constituting the surface material 5 e of the first diaphragm 5. The first diaphragm 5 and the
second diaphragm 6 are disposed to coincide with the angular directions (the dy1 direction and
the dy2 direction in FIG. 3).
[0041]
That is, in the speaker vibration system of the double diaphragm structure of the speaker 1, the
direction not along the weave direction which is the weak direction of the first diaphragm 5
having anisotropy (the 45-degree angle direction between warp and weft) : The first vibration so
that the directions dy1 and dy2 in FIG. 3 coincide with the directions of the four diaphragm
portions 6a and the engaging portion 6b which are strong directions of the second diaphragm 6
having anisotropy. The plate 5 and the second diaphragm 6 are disposed. This is a relationship in
which the first diaphragm 5 and the second diaphragm 6 are arranged such that the direction in
which the rigidity of the first diaphragm 5 is weak matches the direction in which the rigidity of
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the second diaphragm 6 is strong. . Therefore, due to the material anisotropy of the woven fabric
constituting the surface material 5e that is strong in the direction of the warp and weft and weak
in the angular direction of 45 degrees between them, the influence of the divided vibration mode
of the first diaphragm 5 is Even when it becomes large, the divided vibration is mutually
suppressed by the second diaphragm 6 having anisotropy, and the speaker 1 excellent in the
reproduction sound quality with few peaks and dips on the sound pressure frequency
characteristic is realized. Can.
[0042]
FIG. 5 is a view for explaining the vibration mode of the speaker 1 of the present invention and
the speaker 100 (not shown) of the comparative example. In contrast to the speaker 1 of the
present embodiment, the speaker 100 of the comparative example is an electrodynamic speaker
having a speaker vibration system that does not have the second diaphragm 6 and does not have
a dual diaphragm structure. The speaker vibration system of the speaker 100 of the comparative
example is different only in that the second diaphragm 6 is not provided. Therefore, the
description of the voice coil bobbin 2, the voice coil 3, the damper 4, the first diaphragm 5, the
edge 7, the frame 8, the equalizer 9 and the magnetic circuit 10 which are common to each other
will be omitted.
[0043]
As shown in FIG. 5A, in the speaker 1 of the present embodiment, in the speaker vibration system
of the double diaphragm structure constituted by the voice coil bobbin 2 and the first diaphragm
5 and the second diaphragm 6, Since the second diaphragm 6 is disposed to reinforce the surface
material 5e of the diaphragm 5 so as to cancel the anisotropy, the substantially concentric
vibration mode distribution as in the case where the surface material 5e is isotropic. Can be seen.
On the other hand, as shown in FIG. 5B, in the speaker 100 of the comparative example, since the
second diaphragm 6 for reinforcing the first diaphragm 5 is not disposed, the difference in the
surface material 5e of the first diaphragm 5 is different. The directionality is prominent, and the
vibrational mode distribution of four rotational symmetry appears from low frequencies.
Therefore, in the speaker 100 of the comparative example, the piston vibration region of the
speaker vibration system becomes narrow, and the operation of the speaker vibration system
becomes unstable.
[0044]
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Moreover, FIG. 6 is a graph explaining the acoustic characteristic of the speaker 1 of a present
Example and the speaker 100 of a comparative example. In the double diaphragm structure of
the speaker 1 of the present embodiment, the frequency fh of the lowest mode, which is the first
mode in which the outer peripheral side starts divided vibration, is about 2.9 kHz, and at
frequencies below that, the first vibration The plate 5 and the second diaphragm 6 are in piston
oscillation. The speaker vibration system of the double diaphragm structure forming the
separation space Y of the speaker 1 of the present embodiment has a mode in which the division
vibration is started by the anisotropy of the surface material 5 e of the first diaphragm 5 of the
first diaphragm 5. The frequency is pushed up to a higher frequency (about 2.9 kHz in the
present embodiment) by the second diaphragm 6 which is also arranged in a reinforcing
relationship with each other similarly having anisotropy. The piston oscillation area can be
expanded. On the other hand, in the double diaphragm structure of the speaker 100 of the
comparative example, the frequency fh of the first mode in which the outer peripheral side starts
divided vibration is about 1.8 kHz, and the region where the first diaphragm 5 vibrates in a
piston narrows. ing.
[0045]
In a speaker vibration system having a general double diaphragm structure, the total weight of
the speaker vibration system is heavy because the second diaphragm 6 is disposed behind the
first diaphragm 5, and as a result, the low-efficiency speaker There is a problem to say that it
becomes. However, in the speaker 1 of the present embodiment, there is an advantage that the
second diaphragm 6 can be reduced in weight by notching the second diaphragm 6 and
eliminating the space between the adjacent engaging portions 6 b. Further, since the second
diaphragm 6 is configured to define the through hole 6 d, the diaphragm area of the second
diaphragm 6 is substantially reduced. As a result, the double diaphragm structure of the speaker
1 of the present embodiment has an advantage of being able to reduce unnecessary radiated
sound from the second diaphragm 6.
[0046]
In addition, as a base material which comprises the base ¦ substrate of the 1st diaphragm 5,
according to a use and the objective, arbitrary appropriate woven or nonwoven fabrics and
arbitrary appropriate thermosetting resin may be employ ¦ adopted. The substrate may be a
woven fabric or a non-woven fabric alone, or may be a laminate having a plurality of non-woven
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fabrics, or a laminate of a woven fabric and a non-woven fabric. The non-woven fabric typically
includes para-aramid fibers, meta-aramid fibers, rayon fibers, cotton fibers, ultra-high strength
polyethylene fibers, polyarylate fibers and the like. Examples of the woven fabric include
polytrimethylene terephthalate and polyethylene naphthalate (PEN) fibers. The woven or nonwoven fibers may be natural fibers or inorganic fibers as described above.
[0047]
In the surface material 5e of the first diaphragm 5 of the present embodiment, the woven fabric
having anisotropy forming the first diaphragm 5 has a composition ratio of the warp and weft of
the woven fabric of about 1.2 or more. If it is a woven fabric of plain weave, twill weave, twill
weave, satin weave, or satin weave, the Young's modulus changes greatly depending on the
process, and the first diaphragm 5 having the surface material 5 e has a resonant frequency in
the high region dispersed As a result, the sound pressure frequency characteristic tends to be
flat, and the high frequency is not severe in terms of hearing, which makes it very easy to hear.
The anisotropically woven fabric forming the surface material 5e is a woven fabric of twill
(shrink) weave or tweezers (tweezers) weave whose size ratio of the warp and weft of the woven
fabric is about 1.2 or more. And at least at least silk fibers (including silk raw yarn and silk
spinning), cotton fibers, wool fibers, polyester fibers, polyethylene naphthalate fibers, nylon
fibers, aramid fibers, acrylic fibers, polylactic acid fibers, glass fibers and carbon fibers It is
sufficient if it contains one fiber. Also, in the case of a satin weave, the warps are dense relative
to the plain weave and twill weave and the weave points are scattered, so a smooth and glossy
appearance is obtained, so it is placed on the front side. It is suitable for the surface material 5e
of the first diaphragm 5 having a substantially cone shape.
[0048]
Further, in the speaker 1 of the present embodiment, the separation space Y defined between the
first diaphragm 5 and the second diaphragm 6 constituting the double diaphragm structure is
different from the first adhesive Ad1 in the first embodiment. (2) Since the adhesive Ad2 is
applied and filled, the second adhesive Ad2 having a large internal loss suppresses the divided
vibration of the first diaphragm 5 and the second diaphragm 6, and further, the peak · on the
sound pressure frequency characteristic It is possible to realize a speaker excellent in
reproduction sound quality with less dip and less harmonic distortion. The first adhesive Ad1 and
the second adhesive Ad2 differ not only in the constituent components but also in the value of
Young's modulus after curing and also in the value of internal loss. In order to enhance the
rigidity of the speaker vibration system of the double diaphragm structure of the present
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embodiment and to suppress the division vibration, the hardness after the second adhesive Ad2
is relatively cured compared to the first adhesive Ad1 is low. It is desirable that it is soft and has
a small value of Young's modulus and a large value of internal loss.
[0049]
In the case of the present embodiment, the inner peripheral portion 7b of the edge 7 is bonded to
the outer peripheral side of the second diaphragm 6 from the back side and connected. However,
the edge 7 b may be bonded so as to overlap the front surface side of the outer diameter end of
the first diaphragm 5, and in this case as well, the engagement flange portion 5 b of the first
diaphragm 5 can support and move It may be engaged with the annular recess 7d of the portion
7c. It is possible to bond the voice coil bobbin 2 and the second diaphragm 6 without tilting the
first diaphragm 5, and to realize a speaker vibration system of a double diaphragm structure
having sufficient rigidity.
[0050]
In addition, although the speaker 1 of the present embodiment is an electrodynamic speaker
including the bullet-shaped equalizer 9 and not including the dust cap covering the upper end
side of the cylindrical voice coil bobbin 2, the present invention is limited to such an
embodiment. It is not a thing. When the bullet-shaped equalizer 9 is not provided, a dust cap
connected to the voice coil bobbin 2 or the first diaphragm 5 may be provided. In addition, the
first diaphragm 5 formed by impregnating the base material with the thermosetting resin may be
one in which the portion corresponding to the dust cap is integrally formed.
[0051]
The vibration system of the speaker of the present invention can be suitably applied to a speaker
used for various applications (home use, car use). Furthermore, it can be applied to any speaker,
such as a woofer that reproduces particularly in the low frequency region, or a full range speaker
that reproduces also in the high frequency region. Further, the vibration system of the present
invention can be applied not only to the speaker but also to the microphone.
[0052]
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DESCRIPTION OF SYMBOLS 1, 100 speaker 2 voice coil bobbin 3 voice coil 4 damper 5 1st
diaphragm 5a diaphragm part 5b engagement collar part 5c ridge part 5d engagement recessed
part 5e surface material 6 2nd diaphragm 6a diaphragm part 6b engagement part 6c Inner part
6d Through hole 7 Edge 7a Outer part 7b Inner part 7c Support movable part 7d Annular recess
8 Frame 9 Equalizer 10 Magnetic circuit
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