JPS5480733

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DESCRIPTION JPS5480733
Specification 1, Name of the Invention Diaphragm for Speakers α) Prepreg board in which 15 to
25% by weight of one of thermoplastic resin and thermosetting resin is impregnated in plain
weave, twill weave or satin weave carbon fiber woven fabric A speaker diaphragm made by
laminating metal foils on one side or both sides of the sheet and laminating and forming them.
2, the scope of claims
3. Detailed Description of the Invention The present invention relates to a diaphragm for a
speaker having a carbon fiber woven fabric reinforced plastic and a metal foil of aluminum,
titanium or the like superposed on each other to have a laminated or sandwich structure. When a
soft metal such as aluminum is thin, bending stiffness is low and it is easily deformed. For this
reason, not only the handling and product management of the large diameter aluminum speaker
diaphragm is not only difficult during the manufacturing process, but cards other than the
speaker's original function are used so that the customer does not touch it. Although it is
customary to set up a net, this has resulted in an increase in the cost of the product and
diminishes the interest and attraction of touching with the customer's request. Furthermore,
among metal materials, aluminum has a small elastic modulus, has a small internal loss property,
and is limited in the improvement of the characteristics as a speaker diaphragm. An object of the
present invention is to obtain a novel diaphragm for a speaker, which is expected to improve
characteristics by removing defects in manufacturing and handling of the above-mentioned
diaphragm made of metal. According to the present invention, a carbon fiber woven fabric
reinforced plastic and metal foil are laminated with high elasticity, low density, high internal loss
and a very thin plate used as a diaphragm with high bending rigidity and easy handling and
production. Alternatively, a loudspeaker diaphragm is provided which can be configured as a
sandwich laminate, thereby eliminating the defects of the metal diaphragm and simultaneously
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improving the characteristics. Desirably, the carbon fiber woven fabric is selected appropriately
from a plain weave, a twill weave and a satin weave as a yarn type of 100 ° to 3000 filaments, a
basis weight of 80 to 40 of, and EndPage 1 woven structure according to the purpose. Next, one
type is selected from thermoplastic resins such as polycarbonate, polystyrene, polyethylene,
polyester and polyurethane, or thermosetting resins such as phenol, epoxy and polyester, which
are dissolved in an appropriate organic solvent, and this resin The solution is kept at a
temperature of 60 to 80'C, and the carbon fiber woven fabric selected previously is immersed in
this, air-dried and heat-dried to obtain a carbon fiber woven fabric reinforced plastic prepreg
board. An aluminum or titanium foil of a predetermined thickness is laminated on both sides or
one side of this prepreg plate, and cut according to the desired diaphragm size, and this is
molded into a pair of male and female having a shape corresponding to the desired diaphragm
shape. The mixture is placed in a mold, heated and pressed to obtain a final product. The resin
impregnated in the carbon fiber woven fabric sufficiently penetrates into the yarn of the woven
fabric, and is adhered to the metal foil by heating and pressure at the time of molding so as to
maintain the necessary adhesive strength.
In order to maintain the elastic modulus as the speaker diaphragm, the volume content of carbon
fiber in the carbon fiber woven fabric reinforced plastic in the heating and pressure-molded
article is set to 75 or more. Example 1 Yarn type 1000 filament, density 7 7 cm, basis weight 1
oog / m ′ ′, twist number 25 ter 77 m, thickness 120 μ, high elastic carbon fiber woven
fabric of plain weave plain weave, 100 parts of bisphenol A type epoxy resin Then, 0.5 parts of
the curing catalyst 1-cyanony 2-phenylimidasole is mixed and impregnated in a resin solution
dissolved in 120 parts of acetone. The temperature of the resin I solution at this time is 50 ° C.,
and the immersion time is 20 minutes. After resin impregnation, it is dried at 80 ° C. for 15
minutes in air for 30 minutes, and acetone is scattered to obtain a prepreg plate. The volume
content of carbon fibers in the prepreg plate is 78.5%, the cross section of which is shown in FIG.
A 30 μ thick corrosion resistant aluminum foil is superposed on this prepreg plate, cut with a
diameter of 220 mm, taken out, and this is collected between a pair of male and female molds
that define a predetermined diaphragm shape, temperature 160 ° Hold at C for 10 seconds to
preheat, drive the mold so that male and female molds abut, press at 120 kg / c- and hold for 5
minutes. During this time, the epoxy resin impregnated in the carbon fiber woven fabric cures
and bonds with the corrosion resistant aluminum foil. The obtained diaphragm has a thickness of
1 o.mu., an elastic modulus of approximately 8200 to a density of 1.95 g / crl, and an
interlaminar shear strength between a carbon fiber woven plastic and an aluminum foil. The
sound pressure frequency characteristic of the loudspeaker of nominal diameter 25e: '77L by
this diaphragm is, as shown in FIG. 3, the high-resonance frequency 4200 Hl, and the sharp wave
0) becomes smaller. Example 2 The same woven fabric as in Example 1 was impregnated with
para-substituted denatured phenol resin to obtain a prepreg plate. The fiber volume content is
19.6. An aluminum foil is overlapped on this prepreg plate in the same manner as in Example 1
and disposed in a forming die, and the temperature is 180 ° C. and the pressure is 85 kg / cn?
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Heat and pressure for 4 minutes to obtain a desired vibration 4 plate. This diaphragm has a
thickness of 105μ and an elastic modulus of 9100ψ-1 density 1.98y / am ′ ′ and an
interlaminar shear strength of 6.5 to 1 between carbon fiber woven fabric reinforced plastic and
aluminum foil. The sound pressure frequency characteristic is good as shown by numeral 6 in
FIG. Example 3 y is a yarn type 1000 filament, density "70 ms basis weight 10017Q, twist
number 20 turn A1 thickness 120 μm, high elasticity carbon fiber woven fabric of twill weave,
thermoplastic acrylic resin similarly to y The resin solution dissolved in an aromatic hydrocarbon
solvent was impregnated and dried to obtain a prepreg plate.
The volume content of fibers was 80.3%. Place the aluminum foil on top of one another in the
same manner as in Example 1 and heat at 130 ° C and 1 pressure 65 at @ / c- and hold for 1.5
minutes to obtain the desired laminated diaphragm I got This diaphragm has a thickness of
100μ, an elastic modulus of 8800kg / m, and a density of 1.85ji10W? The interlaminar shear
strength between the carbon fiber woven fabric reinforced plastic and the aluminum foil is as
high as 8%, and the sound pressure frequency characteristics are good as shown by the numbers
in FIG. 3 EndPage: 2. The above-described embodiments are merely for the purpose of
illustration, and the present invention can be practiced with various conditions changed in
accordance with the required shape, size and characteristics of the diaphragm. For example, a
carbon fiber woven fabric can be a plain weave, a twill weave or a satin weave, and the yarn type
can be suitably selected in the range of 1000 to 3 o00 filament, 80 to 400 j7 / m "basis weight.
The adhesive may be selected from thermoplastic resins such as polycarbonate, polystyrene,
polyester, polyurethane and acrylic resin, and thermosetting resins such as phenol, epoxy and
polyester. The metal foil may be attached to only one side of the carbon fiber woven fabric
reinforced plastic, or may be attached to both sides. According to the present invention, the metal
foil is adhered by the resin impregnated to constitute the carbon fiber woven fabric reinforced
plastic, and moreover, since the core and the surface are simultaneously formed and bonded, the
core and the surface are separated. As compared with the conventional method of forming an
adhesive, coating and bonding between the two, the process can be significantly simplified, and
the characteristics as a diaphragm can be improved.
4. Brief description of the drawings FIG. 1 is a cross-sectional view illustrating the cross-sectional
structure of a carbon fiber woven fabric-reinforced plastic plate, and FIG. 2 is a portion of a
diaphragm in which a metal foil is adhered to one side of the plate of FIG. A cross-sectional view,
FIG. 3 is a sound pressure frequency characteristic diagram for three embodiments according to
the present invention. 1 is a warp of carbon fiber woven fabric, 2 is a weft, 3 is an impregnated
resin, 4 is a metal foil, 5, 6. F is a characteristic curve corresponding to 1.2.3 of each example.
Attorney Attorney Attorney 1) Toshiyuki EndPage: 3
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