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The present invention relates to a 1 swing plate for a speaker mainly composed of no fiber 1M.
In recent years, the Young's modulus (E) mainly made of inorganic fibers that have high elasticity
other than natural fibers as the main material, in addition to expanding the band of the sound
pressure frequency characteristics of the speaker, as a speaker diaphragm of diameter 1u. A
diaphragm with a high propagation speed (E 70,000) has been developed. As a method of
manufacturing such a diaphragm, there is a paper-making method in which inorganic fibers are
mixed with a thermoplastic resin or its fibers, and a substrate of a predetermined shape is heatformed with a die 19. In addition, a method in which such a paper-making method is improved,
that is, a thermosetting resin is attached to a root-like inorganic fiber sheet and heat pressing is
directly performed with a mold having a predetermined shape to obtain a diaphragm and reduce
the number of required molds. There are also press molding methods and the like. As a
diaphragm formed by directly heat-pressing an inorganic fiber sheet in such a press-forming
method, it is thermally cured to a sheet (woven fabric) in which inorganic fibers are woven in a
cloth shape or a non-woven sheet in which fibers are oriented in a single direction Heatimpregnated resin that has been In these cases, when a diaphragm having a predetermined
shape, for example, a cone shape, is heat-pressed using a sheet of sheet i, the diaphragm formed
by the direction of the inorganic fibers and the direction of the cross yarn may be deformed, In
the area near the top of the cone, there is a disadvantage that the weave of the woven fabric is
greatly stretched and pinholes occur frequently. Accordingly, two or more inorganic fiber sheets
are generally stacked and pressed. However, two or more inorganic 4! Even when the diaphragm
is press-formed by the fiber sheet, the thermosetting resin needs to be sufficiently adhered to the
inorganic fiber sheet in order to prevent pinholes, and a high pressing pressure is also required
in the press-forming. For this reason, as the physical properties of the diaphragm, the density (ρ)
becomes high, and in order to obtain a lightweight diaphragm for broadening the sound pressure
frequency characteristics of the speaker, the laminated inorganic fiber sheet is used. Is not
suitable. The purpose of the present invention is to provide a loudspeaker diaphragm in which
the advantages of the inorganic fibers are taken advantage of and the loudspeaker sound
pressure frequency characteristics are also flat. The diaphragm for a speaker according to the
present invention comprises a thermoplastic resin film layer, and at least one inorganic fiber
layer made of a woven or non-woven fabric mainly composed of an inorganic fiber to which a
thermosetting resin is attached and laminated on the film layer; It is characterized by consisting
of. An embodiment of the present invention will be described based on the attached drawings.
FIG. 1 is a side cross-sectional view of a cone-shaped 1-turning plate 1 according to this
embodiment and an edge 2 and shows that an edge 2 is adhered to the outer peripheral edge of
the diaphragm 1. FIG. 2 is an enlarged sectional view of a portion shown by a circle A in FIG. The
cone-shaped moving plate 1 of the present embodiment is a cloth-like carbon fiber sheet 1a
which is a woven fabric woven mainly of carbon fibers, so that the polyamide resin film 1b
becomes an intermediate layer. It is a diaphragm of a sand-inch structure which is closely
attached to and laminated on the main surface. The speaker diaphragm is manufactured through
the following steps. First, in the impregnation step, the cloth-like carbon fiber sheet having a
basis weight of 150 q / tail is immersed in an epoxy resin solution having a liquid concentration
of 40% by weight to impregnate the epoxy resin between ma. Next, as a drying step, the obtained
impregnated cloth-like carbon fiber sheet is dried with hot air at 100 ° C. for 20 minutes. At this
time, 15% by weight of the epoxy resin was adhered to the cloth-like carbon fiber sheet 3a. If the
adhesion amount of a thermosetting resin such as an epoxy resin to carbon fibers is less than
50% by weight, it is preferable because the flexibility of the sheet is not impaired. Next, as a sheet
forming step, a polyamide resin film 3b of 40 μm thickness is prepared, and the cloth-like
carbon U & miscellaneous sheet 3a after drying is superposed on both main surfaces of the film
3b. A flat plate heated to about .degree. C. is pressed for 5 seconds and bonded to obtain a crossshaped carbon fiber sheet 3 for molding shown in the enlarged partial sectional view of FIG. The
thickness of the intermediate film layer may be in the range of 20 μm to 60 μm. Next, as a
press forming step, the cone-shaped molds 5 and 6 respectively equipped with the heaters 7 as
shown in the schematic cross sectional view of FIG. 4 are heated to about 250 ° C., and between
the molds 5 and 6. And pressing for 20 seconds to obtain an imaging plate 1 of this embodiment.
The following table is obtained by comparing the physical characteristics of the obtained
diaphragm of the above-mentioned embodiment and the conventional diaphragm formed by
overlapping two sheets of cloth-like carbon fibers used in the embodiment. In addition, in order
to compare the magnitude of the number of pinholes of these vibration 1FII roots in the table,
the air permeability of both diaphragms by the air permeability method according to JIS-P8117
is also shown. From the table, the diaphragm of this embodiment has a density (ρ) clearly
smaller than that of the conventional diaphragm at 0.40 / cm 'and the Young's modulus E is
reduced, but the propagation velocity C [77 is 44 And clearly it is getting higher.
Also, in terms of air permeability, the diaphragm of the embodiment has almost no air
permeability at 1300 seconds, and it can be seen that the number and size of pinholes are
smaller and smaller than those of the prior art. . In the present embodiment, the SvJ board of
sandwich structure in which a polyamide resin film is used as an intermediate layer and is
sandwiched between two woven layers of carbon fiber impregnated with an epoxy resin is
laminated. Can be obtained. Also, instead of the carbon fiber woven fabric, it may be a diaphragm
having a sandwich structure of non-woven fabric. l) 如 く 蚤 蚤 如 く 如 く れ ば れ ば According
to the present invention, the polyamide resin layer is an intermediate layer and the sandwich
structure of inorganic fiber woven or non-woven fabric, so that Young's modulus (E), propagation
speed at low density A diaphragm having a large physical property value such as <JF / ρ) is
obtained. In addition, since the conventional diaphragm which is formed by hand bonding an
undifferentiated fiber woven fabric or a non-woven fabric alone is almost free from bepinning
holes, the adhesion of thermosetting resin which is a binder of inorganic fiber woven or nonwoven fabric is reduced. Thus, a diaphragm with reduced manufacturing costs i to is obtained.
Furthermore, a diaphragm having low density as the performance of the diaphragm, and a
propagation speed and a high Fr7T high loudspeaker can be obtained.
Brief description of the drawings
FIG. 1 is a cross-sectional view of the speaker diaphragm of this embodiment, FIG. 2 is an
enlarged partial cross-sectional view of a portion shown by circle A in FIG. 1, and FIG. 3 is a
molding for use in this embodiment FIG. 4 is an enlarged partial cross-sectional view of a sheet,
and FIG. 4 is a schematic cross-sectional view of a mold used in the present embodiment.
Explanation of the code of the main part 1 ..... Vibration plate 2 ..... Etch 3 ..... Forming sheet