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JPH08340595

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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DESCRIPTION JPH08340595
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
speaker edge, and more particularly to material improvement of the speaker edge.
[0002]
2. Description of the Related Art Conventionally, as an edge material for a speaker, cotton or nonwoven fabric impregnated with thermosetting resin such as urethane foam or phenol, woven
fabric made of synthetic resin fiber, and unvulcanized rubber are heated and pressed. And
injection molded thermoplastic elastomers.
[0003]
SUMMARY OF THE INVENTION Among such conventional speaker edge materials, those using a
woven fabric have poor stretchability, so the linearity deteriorates and they can not keep up with
large amplitudes, and in large amplitude regions There is a disadvantage that distortion occurs
when driven.
In addition, although the one using rubber has good stretchability, it has a low rigidity and can
not support the diaphragm correctly, which results in the lateral shake of the diaphragm and the
like. Unlike the above-mentioned materials, foamed urethane can be mentioned as one having
appropriate rigidity and stretchability, but also with this foamed urethane, the partition walls of
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the individual foamed cells undergo high-order resonance at high frequencies, There is a
drawback that the second and third order distortions become large. The disadvantage that the
second and third order distortions increase is also true for the edge made of non-woven fabric
conventionally used. More specifically, the edge made of the conventional non-woven fabric is
given a shape by heat-pressing the non-woven fabric at the melting temperature to melt the
fibers in the non-woven fabric and partially forming a film. Similar to the cells of the urethane
foam, high-order resonance occurs to increase secondary and tertiary distortions.
[0004]
Therefore, the present invention solves the disadvantages of the prior art, and a nonwoven fabric
composed of two or more types of synthetic resin long fibers having different melting
temperatures is the softening temperature of the synthetic resin fiber having the lowest melting
temperature among the synthetic resin fibers. In the above, it is possible to provide an edge for a
speaker having appropriate rigidity and stretchability and low distortion by fusing the
intersections in a state in which each long fiber has stopped the fiber state by performing heat
and pressure molding. To aim.
[0005]
The edge for a speaker according to the present invention for achieving the above object is a
non-woven fabric composed of long fibers of two or more types of synthetic resin fibers having
different melting temperatures among the synthetic resin fibers. A speaker edge formed by being
heated and pressed at a temperature higher than the softening temperature of a synthetic resin
fiber having the lowest melting temperature, in which each intertwined long fiber is in a state of
stopping the fiber state, the intersection is melted A composite filament having a substantially
circular cross-section, which is constructed by combining two or more kinds of synthetic resins
having a substantially bowl-like cross-section and being adjacent to each other so as to be
different synthetic resins. It is characterized in that a non-woven fabric in which extremely long
and thin fibers are entangled and obtained by dividing with a high pressure water stream is used
for the speaker edge.
[0006]
In the speaker edge having such a configuration, the non-woven fabric composed of long fibers
of two or more types of synthetic resin fibers having different melting temperatures is the
softening temperature of the synthetic resin fiber having the lowest melting temperature among
the synthetic resin fibers. By heating and pressing as described above, the long fibers are
entangled in a state in which the shape is maintained, and the intersections of the entangled long
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fibers are fused to maintain the edge shape.
Therefore, the molded product has a large thickness, that is, a high rigidity, since the long fibers
hardly melt and stop the fiber shape.
And since only the intersection of the long fibers is fused, the stretchability of the long fibers
themselves is utilized, and the arrangement shape of the fibers is random (due to being a nonwoven fabric), the mesh structure (the intersections are melted) Since it comes to be worn), the
stretchability becomes good. Furthermore, since such long fibers are not filmed at all,
unnecessary resonance does not occur, resulting in low distortion. Moreover, the range of the
thermoforming temperature for setting it as such a fiber state can be widely taken by the
presence of the long fiber whose melting temperature is higher than the synthetic resin long
fiber which becomes the object of this temperature. That is, in the case of molding with one kind
of synthetic resin long fiber, the thermoforming temperature range may be limited by the
temperature at which the shape of the non-woven fabric (moldable) can be maintained. By being
present, the long fibers contribute to the shape maintenance, and the range of the thermoforming
temperature is expanded.
[0007]
A nonwoven fabric having a substantially circular cross-section, which is configured by
combining non-woven fabrics used for the speaker edge, in such a manner that two or more
types of synthetic resins having substantially ridged cross-sections become different resins
adjacent to each other In the case of a non-woven fabric in which extremely long fibers are
entangled, which is obtained by water flow division, rigidity is further increased due to
entanglement of very long fibers, and the cross section shape of the long fibers is a cross section.
The rigidity is further improved because the contact area of the intersection point between the
entangled long fibers is larger than that of the circular long fibers. In addition, if the crosssectional shape of the long fibers is circular, the intersections between the long fibers may not
partially fuse sufficiently, and there is a risk that the long fibers may be rubbed at this part and
distortion due to this may occur. In addition, when the cross-sectional shape of the long fibers is
substantially wedge-shaped and the contact area at the intersections between the long fibers is
increased, the rubbing of the long fibers is completely eliminated, and the reduction of strain can
be further improved.
[0008]
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EXAMPLES The examples of the present invention will be described in detail. [Example] As
schematically shown in FIG. 1, a composite filamentous fiber 3 consisting of polyethylene
terephthalate 1 and polypropylene 2 and having a resin-like cross-sectional shape substantially
in the form of a ridge is alternately arranged to form a circular cross-section. Nonwoven fabric 4
(shown schematically in FIG. 2) in which the composite long fiber 3 thus obtained is divided into
a substantially bowl-like shape by a high pressure water flow and bipolar elongated fibers having
a fiber thickness of about 0.2 denier or less are entangled. Co., Ltd. Miracle cross]; clamp the
outer periphery of basis weight 160 g / m 2, thickness 0.82 mm, width 250 mm with two metal
rings 5 as shown in FIG. It heat-press-molds for 9 seconds with the heated roll edge shaping |
molding die 6 (6a is an upper type | mold, 6b is a lower type | mold). In this embodiment, the set
temperature of the edge molding die 6 is set to about 140 ° C., but is set to about 130% to
about 150 ° C., ie, about 145% to about 165% of the softening temperature of 90 ° C. of
polypropylene. It should be done. In the apparatus of this embodiment, the heat pressing time is
9 seconds, but if the heating time is 5 seconds or more, molding can be sufficiently performed.
The inner periphery and the outer periphery of the obtained molded product were cut to obtain a
roll edge having an outer diameter of φ160, an inner diameter of φ115, and a thickness of 0.5
mm. Comparative Example 1 A urethane foam having a basis weight of 283 g / m 2, a density of
0.03 g / cm 3 and a thickness of 9.5 mm is heat-pressed for 10 seconds with a roll edge molding
die heated to 220 ° C. The inner periphery and the outer periphery of the obtained molded
article having a density of 0.28 g / cm 3 and a thickness of 1.0 mm were cut to obtain roll edges
having an outer diameter of φ160 and an inner diameter of φ115. Comparative Example 2 A
base material prepared by coating a urethane resin at 68 g / m 2 on a polyester fiber woven
fabric having a basis weight of 100 g / m 2 and a thickness of 1.0 mm was produced using a roll
edge molding die heated to 200 ° C. Hot press molding for 10 seconds. The inner and outer
peripheries of the obtained molded article having a density of 0.56 g / cm 3 and a thickness of
0.3 mm were cut to obtain roll edges having an outer diameter of φ160 and an inner diameter
of φ115.
[0009]
Next, the physical properties of this example and the respective physical properties of
Comparative Examples 1 and 2 are shown in Table 1.
[0010]
As is clear from Table 1, although the speaker edge of the example has a slightly lower
elongation and internal loss than the speaker edge of Comparative Example 1, the Young's
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modulus and the rigidity ratio are extremely large.
Also, compared with the speaker edge of Comparative Example 1, the internal loss was a little
inferior, but the elongation, Young's modulus and rigidity ratio became remarkably large.
[0011]
An electron micrograph of the inside at the edge of this example is shown in FIG. 4
(photographed at 100 ×).
[0012]
As apparent from the photograph, at the edge of the present embodiment, the long fibers hardly
melt at the surface and the inside thereof, and the fiber shape remains stopped.
[0013]
Next, FIG. 5 shows a frequency characteristic diagram of the speaker manufactured using the
speaker edge of this example, and FIG. 6 shows a frequency characteristic graph of the speaker
manufactured using the edge of Comparative Example 1.
In the speaker production, both of the edges were produced using the same magnetic circuit and
the same cone paper with a diameter of 16 cm.
In FIGS. 5 and 6, solid lines indicate sound pressure characteristics, and dotted lines and
alternate long and short dash lines indicate second-order distortion and third-order distortion,
respectively.
[0014]
As is clear from these characteristic diagrams, in the speaker edge of this example, both the
second-order distortion and the third-order distortion are reduced by 5 to 20 dB at 400 Hz to 10
kHz as compared with the speaker edge of Comparative Example 1. With respect to this, in the
case of using urethane foam, it is considered that the thin partition walls of the fine cells of
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urethane foam generate resonance at a high frequency, which amplifies second-order distortion
and third-order distortion.
[0015]
As described above, the speaker edge according to the present invention has been described in
detail based on an example considered to be representative, but the embodiment of the speaker
edge according to the present invention is not limited to the shape of the edge. In the above,
polyethylene terephthalate having a melting point of 256 ° C and polypropylene having a
melting point of 176 ° C were used as synthetic resin filaments having different melting
temperatures, but other synthetic resin filaments having different melting temperatures may be
combined, The present invention is not limited to the structure of the above-mentioned
embodiment, for example, may be used synthetic resin long fibers of more than kinds, and
includes the constituent requirements described in the above-mentioned claims, and exhibits the
action according to the present invention, As long as it has the effects described below, it can be
modified as appropriate.
[0016]
The speaker edge according to the present invention has the following effects.
(1) Since the long fibers are entangled in the state of maintaining their shape, and the
intersections of the entangled long fibers are fused to maintain the edge shape, the molded
product has a large thickness, ie, high rigidity. Therefore, the diaphragm can be supported in an
ideal state. (2) By fusing only the intersection points of the long fibers, the stretchability of the
long fibers themselves is utilized and the arrangement shape of the fibers becomes random, so
that the stretchability becomes good, the linearity is excellent, and the large amplitude region No
distortion occurs even if driven by (3) Since the long fiber stops its fiber state and is not filmed at
all, unnecessary resonance is not generated by this and distortion can be significantly reduced
compared to the conventional one. (4) The range of the thermoforming temperature for
obtaining such a fiber state can be widely taken by the presence of long fibers having a melting
temperature higher than that of the synthetic resin long fibers targeted for this temperature, and
the molding operation is simplified. Be done. (5) It can be obtained by dividing a composite
filament having a substantially circular cross-section, which is formed by combining two or more
types of synthetic resins that are approximately in a cross-section having a plurality of types of
synthetic resins different from each other. In addition, in the case of using a non-woven fabric in
which extremely long fibers having a cross-sectional ridge-like shape are entangled, the rigidity is
further improved by intertwining ultra-long thin fibers having a substantially wedge-like cross
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section and increasing the contact area of the intersections between long fibers. (6) Furthermore,
in the case of those constituted by a plurality of kinds of very long and narrow fibers having a
cross-sectional shape, the contact area at the intersections between the long fibers is increased,
which occurs when the intersections between the long fibers are not sufficiently fused. The
rubbing between the long fibers is completely eliminated, and the distortion can be further
improved.
[0017]
Brief description of the drawings
[0018]
FIG. 1 is a view for explaining a composite long fiber before preparation of a non-woven fabric
used in the speaker edge of the embodiment.
[0019]
The figure explaining the nonwoven fabric used by the edge for speakers of the FIG. 2 Example.
[0020]
The figure explaining the shaping | molding process of the edge for speakers of the FIG. 3
Example.
[0021]
FIG. 4 is an electron micrograph (× 100) showing the shape of fibers inside the speaker edge of
the embodiment.
[0022]
FIG. 5 is a frequency characteristic diagram of a speaker using the speaker edge of the
embodiment.
[0023]
6 is a frequency characteristic diagram of a speaker using the speaker edge of Comparative
Example 1.
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[0024]
Explanation of sign
[0025]
1 polyethylene terephthalate filaments 2 polypropylene filaments 3 composite filaments 4 nonwoven fabric 5 metal ring 6 mold
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