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JP2007336291

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
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DESCRIPTION JP2007336291
To provide a speaker diaphragm having a small difference in strength between a longitudinal
direction (latitude direction) and an oblique direction, and excellent dimensional stability. A
speaker diaphragm of the present invention comprises a woven fabric and a resin applied to at
least one side of the woven fabric, and the woven fabric of the woven fabric comprises plain
weave, twill weave and / or satin weave. In combination with [Selected figure] Figure 1
Speaker diaphragm and speaker
[0001]
The present invention relates to a speaker diaphragm and a speaker. More particularly, the
present invention relates to a speaker diaphragm and a speaker having a small difference in
intensity between the warp direction (latitude direction) and the oblique direction, and excellent
dimensional stability.
[0002]
The tweeter (small) speaker diaphragm is usually formed of metal foil, polymer film, coating cloth
or the like. The coated fabric is typically formed by applying a resin to the surface of the woven
fabric. In general, the speaker diaphragm is required to have high rigidity (Young's modulus) and
high internal loss (tan δ).
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[0003]
Therefore, a speaker formed by applying resin to a plain weave woven fabric in which yarns of
different thicknesses are periodically mixed and arranged in at least one of the longitudinal
direction (transverse direction) and the lateral direction (latitude direction). A diaphragm has
been proposed (see Patent Document 1). The speaker diaphragm can be excellent in the
longitudinal and latitudinal strengths. However, the speaker diaphragm is inferior in strength in
the oblique direction, and as a result, there is a problem that the speaker diaphragm is deformed
due to molding or time-dependent change.
[0004]
By the way, in the speaker diaphragm which apply ¦ coated and shape ¦ molded resin to woven
fabric, there is a high possibility that the woven fabric may not be covered with resin apply ¦
coated completely. Therefore, the woven fabric is susceptible to the surrounding environment,
and has a problem that the dimensional stability is poor particularly in a high humidity
environment. In particular, in a small speaker, the influence of the dimensional change on the
acoustic characteristics can not be ignored even if the dimensional change is minute. JP 2000175290 A
[0005]
The present invention has been made to solve the above-described conventional problems, and
its main object is to provide a speaker diaphragm having a small difference in strength between a
warp direction (latitude direction) and a diagonal direction and excellent dimensional stability. It
is to provide a speaker.
[0006]
The speaker diaphragm of the present invention has a woven fabric and a resin applied to at least
one side of the woven fabric, and the woven fabric of the woven fabric is a combination of plain
weave, twill weave and / or satin weave. is there.
[0007]
In a preferred embodiment, the twill weave and / or satin weave of the woven fabric is arranged
in the left diagonal direction and the right diagonal direction with respect to the warp.
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[0008]
In a preferred embodiment, the twill weave and / or satin weave of the woven fabric is arranged
substantially equally in the left diagonal direction and the right diagonal direction.
[0009]
In a preferred embodiment, the oblique direction is approximately 45 ° to the warp.
[0010]
In a preferred embodiment, the woven fabric is periodically arranged in the warp direction and
the weft direction, and has sub yarns thicker than the main yarn constituting the woven fabric.
[0011]
According to another aspect of the present invention, a speaker is provided.
This speaker comprises the above-mentioned speaker diaphragm.
[0012]
According to the present invention, by mixing different woven structures, the contact point
between the warp and the weft may become irregular, and the deviation in the oblique direction
may be dispersed.
As a result, the strength reduction in the oblique direction can be suppressed, and a speaker
diaphragm having a small difference in strength between the warp direction (latitude direction)
and the oblique direction and excellent dimensional stability can be obtained.
As a result, the speaker diaphragm of the present invention can be particularly suitably used for
a tweeter (small) speaker.
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[0013]
Hereinafter, preferred embodiments of the present invention will be described, but the present
invention is not limited to these embodiments.
[0014]
The speaker diaphragm of the present invention comprises a woven fabric and a resin applied to
at least one side of the woven fabric.
By applying the resin to the woven fabric, a laminated structure having a woven fabric layer and
a resin layer can be formed.
As a result, high stiffness and high internal loss can be achieved.
Each of these will be described below.
[0015]
A.
Woven fabric FIGS. 1 to 4 are schematic plan views showing the woven fabric used for the
speaker diaphragm according to the preferred embodiment of the present invention. In FIGS. 1 to
4, black squares indicate warps and white squares indicate wefts. The woven texture of the
woven fabric used in the present invention is a combination of plain weave, twill weave and / or
satin weave. Unlike warps and wefts arranged regularly as in plain weave, by mixing different
weave structures, the contact points between the warps and wefts may become irregular, and
skew in the oblique direction may be dispersed. As a result, the strength reduction in the oblique
direction can be suppressed, and a speaker diaphragm having a small difference in strength
between the warp direction (latitude direction) and the oblique direction and excellent
dimensional stability can be obtained. Also, by combining twill weave and / or satin weave, the
fabric weight can be improved, and the fabric strength of the entire woven fabric can be
improved. Furthermore, the twill weave and the satin weave have a large contact area between
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the warp and the weft, and the internal friction between the yarns can be large. As a result,
internal loss can be improved. Furthermore, plain weave, twill weave and satin weave can be
excellent in uniformity of the thickness of the contact portion between yarns unlike the case of
triaxial weave and tetraaxial weave. As a result, the clearance of the mold at the time of press
molding of the speaker diaphragm can be easily set, and excellent productivity can be obtained.
[0016]
As a method of combining the plain weave with the twill weave and / or the satin weave, any
appropriate method may be adopted. Preferably, as shown in FIGS. 1 to 4, twill weave and / or
satin weave is arranged in the left diagonal direction and the right diagonal direction with
respect to the warp (weft). More preferably, twill weave and / or satin weave is arranged
substantially equally in the left diagonal direction and the right diagonal direction. With such a
woven structure, the difference in strength between the warp direction (latitude direction) and
the diagonal direction may be smaller. That is, the anisotropy of the woven fabric can be reduced.
As a result, a speaker diaphragm extremely excellent in dimensional stability can be obtained.
[0017]
The oblique direction is preferably about 45 ° with respect to the warp (weft). With such a
woven structure, the difference in strength between the warp direction (latitude direction) and
the diagonal direction may be smaller. That is, the anisotropy of the woven fabric can be reduced.
As a result, a speaker diaphragm extremely excellent in dimensional stability can be obtained.
Furthermore, twill weave and / or satin weave may form the desired weave pattern. It is because
it can be excellent in design. As a woven pattern, for example, a lattice shape as shown in FIGS. 1
and 2 and a polygonal shape such as a hexagon as shown in FIGS.
[0018]
As a specific example of the twill weave, a three-sheet diagonal pattern weave, a four-layer
diagonal pattern weave, etc. may be mentioned. As a specific example of the above-mentioned
satin weave, an eight-piece satin weave etc. are mentioned. Preferably, a four-sheet diagonal
weave and an eight-sheet satin weave are used. The contact area between the warp and the weft
may be larger and the internal friction between the yarns may be greater. As a result, internal
loss can be improved.
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[0019]
The fabric weight of the woven fabric is preferably 30 to 150 g / m <2>, more preferably 35 to
100 g / m <2>, and particularly preferably 40 to 70 g / m <2>. When the weight per unit area is
less than 30 g / m <2>, the fibers are rubbed by vibration, and as a result, there is a possibility
that an unnecessary sound may be generated.
[0020]
As the thickness of the fibers constituting the woven fabric, fibers of any appropriate thickness
may be adopted depending on the purpose. It is preferably 20 to 300 denier, more preferably 30
to 200 denier, and particularly preferably 40 to 150 denier. When the thickness of the fiber is
less than 20 denier, the basis weight often decreases and the strength is often insufficient. When
the thickness of the fiber exceeds 300 denier, the weight increases and as a result, the sound
pressure often decreases.
[0021]
Preferably, the woven fabric has an auxiliary yarn thicker than the main yarn constituting the
woven fabric. By mixing yarns of different thicknesses, the strength of the woven fabric can be
excellent and the rigidity can be improved. Furthermore, the occurrence of resonance can be
suppressed, and acoustic characteristics can be improved. The sub yarns are preferably arranged
periodically in the warp and weft directions. With such a configuration, the formability is
excellent and the anisotropy of the woven fabric can be reduced. The thickness of the fibers
constituting the secondary yarn is preferably 3 times or more, more preferably 3 to 5 times the
thickness of the fibers constituting the main yarn. This is because the deterioration of the
formability due to the difference in yarn thickness can be prevented. Typically, the thickness of
fibers constituting the main yarn is 30 to 60 denier, and the thickness of fibers constituting the
secondary yarn is 100 to 150 denier. As for the arrangement ratio of the main yarn and the sub
yarn, it is preferable to arrange one sub yarn every 5 to 30 main yarns, more preferably one sub
yarn every 10 to 25 main yarns.
[0022]
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Any appropriate material can be adopted as the material of the fiber. Preferably, polyester fibers
such as polyethylene naphthalate (PEN) and polyethylene terephthalate (PET), synthetic fibers
such as aramid fibers and synthetic carbon fibers such as polyparaphenylene benzobisoxazole
(PBO); Inorganic materials such as glass fibers and carbon fibers Fibers include natural fibers
such as cotton fibers.
[0023]
In addition, the said woven fabric may have the thermosetting resin previously impregnated and
hardened ¦ cured to this woven fabric separately from resin mentioned later.
[0024]
B.
Resin Any appropriate resin may be employed as the resin. Specifically, acrylic resin, urethane
resin, melamine resin, modified rubber resin, phenol resin and the like can be mentioned. These
resins may be used alone or in combination of two or more.
[0025]
The woven fabric / resin ratio of the substrate is preferably in the range of 20/80 to 80/20,
more preferably in the range of 50/50 to 70/30. With the fiber / resin ratio in this range, a
loudspeaker diaphragm having extremely excellent internal loss can be obtained without
lowering the rigidity. In addition, the generation of resin-specific sound can be prevented. Here,
the "woven fabric / resin ratio" refers to the ratio of the weight of the woven fabric before
coating to the weight of the coated resin.
[0026]
Any appropriate method may be employed as the application method. Typically, there is a
method of preparing a coating solution containing the above-mentioned resin and coating the
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coating solution on the above-mentioned woven fabric using a coating apparatus.
[0027]
Any appropriate solvent can be adopted as the solvent of the coating solution according to the
type of resin used and the like. Specific examples include water, methanol, ethanol, isopropyl
alcohol and the like. The coating solution may contain optional components in addition to the
resin. As an optional ingredient, a thickener, an antifoamer, etc. are mentioned, for example.
[0028]
The viscosity of the coating solution may be set to any appropriate value. Preferably it is 5005000 cps, More preferably, it is 1000-5000 cps. This is because the resin can be applied
uniformly.
[0029]
As said coating apparatus, a doctor knife coater, a comma doctor, a roll coater etc. are mentioned,
for example. The number of times of application can be appropriately set in accordance with the
concentration, viscosity and the like of the application liquid. Preferably, it is multiple times. This
is because the resin can be applied uniformly. Several types of the coating solution may be used.
Typically, an undercoat coating solution and a topcoat coating solution can be used. As a specific
example, there is a method in which a coating solution for undercoat containing an acrylic
emulsion is applied 2 to 4 times, and then a coating solution for top coat containing a modified
rubber resin is applied 1 to 2 times. When coating is repeated several times, preferably, drying is
performed each time coating is performed. This is because the resin can be applied uniformly.
[0030]
Any appropriate method may be adopted as the method of forming the speaker diaphragm of the
present invention. Typically, after applying the above resin to the above-mentioned woven fabric,
a method of press molding with a predetermined mold (for example, dome shape, cone shape)
can be mentioned.
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[0031]
Hereinafter, the present invention will be more specifically described by way of examples, but the
present invention is not limited by these examples. In the Examples and Comparative Examples,
parts and percentages are by weight unless otherwise indicated.
[0032]
(Preparation of Coating Solution for Undercoat) A coating solution for undercoat having the
following composition was prepared. Acrylic emulsion (manufactured by Dainippon Ink and
Chemicals, Inc.) 100 parts Melamine 3 parts Thickener 40 parts Antifoamer 0.01 part The
viscosity of the obtained coating liquid for undercoat was 2000 cps.
[0033]
(Preparation of Coating Liquid for Top Coat) A coating liquid for top coating having the following
composition was prepared. Carboxyl group-modified methyl methacrylate butadiene rubber
(MBR) 100 parts Melamine 1.5 parts Thickener 1 part Antifoamer 0.01 part The viscosity of the
obtained top coat application liquid was 4200 cps.
[0034]
(Weaving of the woven fabric A) In the warp direction, yarns composed of polyester fibers of 135
denier in thickness were arranged every 23 yarns composed of polyester fibers of 45 denier in
thickness. As in the latitudinal direction, yarns composed of polyester fibers having a thickness of
135 denier were arrayed every 23 yarns composed of polyester fibers having a thickness of 45
denier. The driving number was 120 longitudinal directions / inch × 112.5 lateral directions /
inch. The basic structure of the woven structure was plain weave, and the diagonal direction in
the lattice surrounded by 135 denier yarns was twill weave (quadruple diagonal weave). Thus, a
woven fabric (weight per unit weight 41 g / m <2>) as shown in FIG. 1 was woven.
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[0035]
(Weaving of the woven fabric B) In the warp direction, yarns composed of polyester fibers of 135
denier in thickness were arranged every 15 yarns composed of polyester fibers of 45 denier in
thickness. In the latitudinal direction, yarns composed of polyester fibers having a thickness of
135 denier were arranged every 13 yarns composed of polyester fibers having a thickness of 45
denier. The driving number was 113 longitudinal directions / inch × 105 lateral directions /
inch. The basic structure of the woven structure was plain weave, and the diagonal direction in
the lattice surrounded by 135 denier thick yarn was twill weave (triple diagonal weave). Thus, a
woven fabric (weight per unit area 50 g / m <2>) as shown in FIG. 2 was woven.
[0036]
(Weaving of Woven Fabric C) In the longitudinal direction, yarns composed of polyester fibers of
45 denier in thickness were arranged at a driving count of 163 / inch. In the latitudinal direction,
a yarn composed of polyester fiber of 45 denier in thickness was arranged at a driving number of
114 / inch. The basic structure of the woven structure is plain weave, with a maximum of 11
warps, and a maximum of 23 wefts, and is twill weave (four sheets diagonal weave). Thus, as
shown in FIG. 3, a woven fabric (weight per unit area 54 g / m <2>) having a hexagonal unit
surrounded by a four-sheet diagonal weave was used.
[0037]
(Weaving of the woven fabric D) In the longitudinal direction, a yarn composed of polyester
fibers of 45 denier in thickness was arranged at a driving number of 175 / inch. In the latitudinal
direction, a yarn composed of polyester fiber of 45 denier in thickness was arranged at a driving
number of 124 / inch. The basic composition of the woven structure is plain weave, with a
maximum of 9 warps, and a maximum of 21 wefts with a satin weave (eight-sheet satin weave).
Thus, as shown in FIG. 4, a woven fabric having a hexagonal unit surrounded by an eight-sheet
satin weave is used as a basic unit (surface weight 61 g / m <2>).
[0038]
(Weaving of woven fabric E) A yarn composed of polyester fibers of 45 denier both in warp and
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weft was plain weaved with the number of the punched in: 130 yarns / inch × 122 yarns / inch.
Thus, a woven fabric with a basis weight of 40 g / m <2> was woven.
[0039]
(Weaving of Woven Fabric F) In the warp direction, yarns composed of polyester fibers of 135
denier in thickness were arranged every 17 yarns composed of polyester fibers of 45 denier in
thickness. As in the latitudinal direction, yarns composed of polyester fibers having a thickness of
135 denier were arranged every 17 yarns composed of polyester fibers having a thickness of 45
denier. The number of the punched sheets: plain weave in 110 warp directions / inch × 92.5
warp directions. Thus, a woven fabric with a basis weight of 36 g / m <2> was woven.
[0040]
(Coating) On one side of the woven fabric A, the coating solution for the above-mentioned
undercoat was applied by a doctor knife coater (a clearance of 0.1 mm of a knife blade). The
coating conditions were coating speed: 10 m / min, drying temperature 120 ° C., drying time 2
minutes, and this operation was repeated three times. Furthermore, the coating solution for top
coat was applied by a doctor knife coater. The coating conditions were coating speed: 10 m /
min, drying temperature 120 ° C., drying time 2 minutes, and this operation was repeated once.
The total basis weight after application of the resin was 74 g / m <2>.
[0041]
(Molding of speaker diaphragm) The woven fabric coated with the above resin is set in a mold
and press molded under conditions of a mold temperature of 220 ° C., a press pressure of 450
kg / cm <2> and a press time of 18 seconds, speaker vibration I got a board.
[0042]
A speaker diaphragm was obtained in the same manner as in Example 1 except that the woven
fabric B was used instead of the woven fabric A.
In addition, the total fabric weight after apply ¦ coating resin was 84 g / m <2>.
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[0043]
A speaker diaphragm was obtained in the same manner as in Example 1 except that the woven
fabric C was used instead of the woven fabric A. In addition, the total weight per unit area after
applying the resin was 87 g / m <2>.
[0044]
A speaker diaphragm was obtained in the same manner as in Example 1 except that the woven
fabric D was used instead of the woven fabric A. In addition, the total weight per unit area after
applying the resin was 96 g / m <2>.
[0045]
Comparative Example 1 A speaker diaphragm was obtained in the same manner as in Example 1
except that the woven fabric E was used instead of the woven fabric A. In addition, the total
weight per unit area after applying the resin was 78 g / m <2>.
[0046]
Comparative Example 2 A speaker diaphragm was obtained in the same manner as in Example 1
except that the woven fabric F was used instead of the woven fabric A. In addition, the total
weight per unit area after applying the resin was 69 g / m <2>.
[0047]
The prepared speaker diaphragm is cut into a predetermined size (3 cm in the longitudinal
direction × 1.5 cm in the transverse direction), and the Young's modulus and internal loss (MD)
in the transverse direction (MD), the transverse direction (CD) and the diagonal direction (OD)
The tan δ) was measured by a vibration lead method in a cantilever manner. The measurement
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results are shown in Table 1 together with the intensity ratio. The strength ratio indicates the
ratio of the latitudinal direction (CD) to the oblique direction (OD) when the Young's modulus in
the warp direction (MD) is 1.
[0048]
[0049]
As shown in Table 1, in Examples 1 to 4, the intensity difference between the warp direction
(MD), the weft direction (CD) and the oblique direction (OD) was smaller than that of
Comparative Examples 1 and 2.
Moreover, compared with Comparative Examples 1-2, Examples 1-4 were excellent in both
Young's modulus and internal loss. Furthermore, in Examples 1 to 4, the difference in strength
between the warp direction (MD), the weft direction (CD) and the diagonal direction (OD) is small,
so that they are not easily affected by the surrounding environment, and dimensional stability
under high humidity environment It can be said that it is excellent.
[0050]
The speaker diaphragm of the present invention can be suitably used for a speaker for any
application. In particular, it can be suitably used as a tweeter (small).
[0051]
It is a schematic plan view of a preferred embodiment of the woven fabric used for the speaker
diaphragm of the present invention. FIG. 7 is a schematic plan view showing another preferred
embodiment of the woven fabric. FIG. 7 is a schematic plan view showing another preferred
embodiment of the woven fabric. FIG. 7 is a schematic plan view showing another preferred
embodiment of the woven fabric.
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