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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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The present invention relates to an improvement of a speaker horn of a horn type speaker and a
method of manufacturing the improved speaker horn. Conventionally, as speaker horns,
aluminum rams of the material are formed by tie casting method, casting method using sand
mold or by cutting, etc., those obtained by assembling essential plates, and those obtained by
molding plastic by inneechnoyon method, etc. . However, the aluminum cast by the tie cast
method is expensive because the equipment cost is high, such as requiring a mold or an
expensive upper injection device, and the sand casting method has to change the sand mold into
one and further finish processing The process required is complicated, and the horn by cutting
has a long time in the cutting process and can not be made expensive due to the generation of
unnecessary chips and the like. Also, the wooden pawn requires a process of accurately cutting
the plate into n dimensions and assembling it accurately, which also can not be expensive.
Furthermore, the plastic horn by the I / Jo-Xoong method is the simplest method in terms of
production, but if the thickness is increased, secondary foaming and sinking will occur, making it
difficult to accurately obtain the shape and dimensions. It has the disadvantage that it can not be
made too thick. Also, from the viewpoint of the characteristics of the horn, it is required that the
internal loss is large, the weight is large, and the mechanical strength is a dog in order to avoid
resonance with the sound wave propagating in the horn, but the aluminum horn Since the
internal loss is extremely small, it is likely to resonate to cause so-called horn noise, and in order
to prevent this, so-called tetdoninks for fixing the vibration absorbing material to the horn outer
wall are required, and the horn noise can be sufficiently suppressed by this detoning. Not. It has a
drawback. Further, since the plastic horn can not have a sufficient thickness as described above,
although the plastic internal loss is large, the effect of suppressing the resonance is small. The
present invention considers the disadvantages of the above-mentioned conventional horns, and is
a horn formed with a thermoplastic resin sheet, filled with a space or other material inside, and a
method of manufacturing the same, which can not be achieved conventionally. The following
examples will be described together with their manufacturing methods. FIG. 1 shows a molding
apparatus for molding a speaker horn according to the present invention, wherein a and lb are
polypropylene sheets (large: 1., 5 mm :) with their edge portions clamped respectively, which will
be described later So la forms the outer wall of the horn, lb forms the inner wall of the horn. 2 is
a heater for heating the polypropylene sheets la and lb, preferably a far infrared heater. 3 is a
convex mold, and the diameter decreases toward the tip in a conical shape, and a convex portion
3a having a flat portion 3b at the top, and attachment of the convex portion is a flat portion 3c in
which the root is horizontally extended, A plurality of cylindrical projections 3d are provided.
The projection 3d is for providing a horn attachment hole to be described later. Denoted at 4 is a
concave mold having a recess 4a having an inner diameter larger than the outer diameter of the
protrusion and having a flat portion 4b on the bottom of the recess 4a. Then, when the convex
portion 3a and 4a of the concave and convex molds insert the convex mold 3 into the concave
mold 4 and the top flat portion 31 of the convex portion 3a abuts on the bottom flat portion 4b
of the concave portion 4a, The flat portion 3 of the convex mold 3 is dimensioned so as to abut
on a step 4 d formed on the outer edge of the flat portion 4C which horizontally extends the
opening of the concave portion 4 a of the concave mold 4. Further, small holes 3e, 4e are drilled
at appropriate places of the uneven portions 3a, 4a and the flat portions 3c, 4c, and the small
holes 3e, 4e are connected to a vacuum pump, preferably a vacuum pump with buffer (not
shown). It is done. Reference numeral 5 is a pin for forming a through hole in the polypropylene
sheet 1a. The pin 5 is disposed so as to protrude from the flat portion 4C of the concave mold 4,
and a heating device (heater) 5a is incorporated And, in the normal state of the pin 5 and the
protruding state of the pin 5, it is assumed that there is provided a conduction hole 5b opened in
the state where the pin 5 is retracted and in communication with the outside air. Next, according
to the manufacturing method using the molding apparatus (1: first, 2 strains of polypropylene
sheet by the heater 2) 1a and 1b are respectively heated to 1608C to 170C. Then, the
polypropylene sheets la and lb are softened and slackened, and then tensioned by surface
tension. In this state, the heater 2 is removed, the concave mold 4 is moved to one side, the
convex mold 3 is moved downward, the polypropylene sheet 1a, lb is pressed and deformed, and
at the same time 500 to 600 mHg Vacuum is applied for 2 to 3 seconds by vacuum degree, and
the mold is put in contact with the die 4a, 4b and the flat portion 4C, and the polypropylene
sheet 1b is a convex portion 3a, 31] flat portion 3c, Close to each surface of the protrusion 3d.
And the contact parts of both molds, that is, the flat part 3b of the convex mold and the concave
bottom face 4b of the concave mold 1 flat part 3C of the convex mold 3 and the stepped part 4d
of the concave mold 4 and the convex The polypropylene sheets 1a and 1b pressed to each of
the projection 3d of the mold 3 and the flat portion 4C of the concave mold are
thermocompression-bonded. On the other hand, the remaining part is formed by forming a space
corresponding to the dimensional difference between the polypropylene sheets la and 1b. On the
other hand, after the uneven mold is fitted, the pins 5 heated by the heating device 5a are
protruded to pierce the through holes 31 in the polypropylene sheet la (Fig. 3-a), then retract the
pins 5 (Fig. 3-b).
Then, the conduction hole 5b is opened, and the heated air between the polypropylene sheets la
and 1b is released through the through hole 31. When the air is cooled next, the outside air is
introduced to maintain the balance of the air pressure in the space, And the deformation of the
sheet due to the pressure change of the space after molding is prevented. Also, compressed air
can be made to flow from the drilled holes 37 to further improve the close contact of the
respective polypropylene sheets to the mold surface 3, and after the sheets are cooled, they are
taken out of the mold, and the thermocompression bonding is carried out. The speaker horn
shown in FIG. 4 is obtained by cutting the cut portion. The speaker horn obtained by such a
manufacturing method has an extremely rigid structure because it has a double wall (h structure)
in which the sheath 1a has an integral outer wall, a sort b) or an inner wall which becomes a
horn sound path. Since the thermoplastic resin has a large internal loss, the so-called horn noise
due to horn resonance can be suppressed due to the high sound insulation effect between the
inner side wall and the outer side wall and the thermoplastic resin itself having a large internal
loss. Further, the mounting hole 32 can be simultaneously formed in the horn opening outer
edge portion 33 and the outer edge portion 33 to be the horn mounting portion. Further, since
the above-mentioned manufacture is extremely simple and resin materials suitable for mass
production and low in cost can be used, it is possible to provide a low-cost speaker horn having
good characteristics. In addition, as horn materials that can be produced by such a production
method, besides polypropylene, copolymers comprising mainly polypropylene, polyethylene,
copolymers comprising mainly polyethylene, acrylic styrene, polystyrene, and thermoplastic
resins such as vinyl chloride Resin, inorganic fiber or inorganic powder such as SiC, TiO carphone
graphite, crow, mica, talc and calcium carbonate as filler for the thermoplastic resin, organic
powder such as wood powder, crystallized cellulose and natural cellulose etc. Or a composite
phase prepared by mixing appropriately-packed inorganic powder, inorganic fiber, and organic
powder, or two different sheets la and 1b selected from “2” materials. It may be selected from
the materials listed above. Further, as shown in FIG. 5, the horn characteristic of the present
invention can be further improved by filling the space portion with the filler 51 according to the
purpose from the through holes 31. For example, materials with relatively large internal loss to
give internal loss to suppress resonance, for example foam such as urethane foam, coal tar,
pinch, mixture of ferrite and polyester, crystallized nylon and iron powder Mixture, epoxy and
organic clay, silicone resin (preferably room temperature curing type) and Shirasu balloon, a
mixture of balloon and polyester such as carbon balloon, etc. are suitable as the filler 51, and the
weight is increased (ie, increase of apparent specific gravity 1 self strength) Suitable materials for
the preparation include, for example, coal tar, a mixture of mineral and inorganic substances
such as sand, cement, sera and sludge (organic fibers), a mixture of I-13-notal or pitch, or filler
51. Most of the fillers could achieve their purpose to increase the rigidity.
By filling the space with the filler 51 as described above, the increase in mechanical strength, the
increase in weight, and the increase in internal loss can be made old, and the resonance of the
horn can be further suppressed. Although the conical horn has been described in the second
embodiment, the present invention is also applicable to various horns having an exponential
constant t: /, and other opening constants, in which case the protrusion of the convex mold 3 is
used. The shape of 3a may be adapted to the sound conduction of the horn. The concave mold
may be configured to contact at least the flat part 3b of the convex mold to be the horn throat
and the flat part 3C of the convex mold to be the opening edge outward part of the horn. You do
not need In the embodiment, the horn taking portion is integrally formed, but the horn does not
have to be integral, and only the horn may be manufactured according to the present invention
and a separate mounting plate may be fixed. . As described in (2), the present invention
comprises a thermoplastic resin sheet or a mixture sheet in which the thermoplastic resin is
mixed with a filler, and the inner side wall and the outer side wall forming the horn are integrally
formed. A horn having a space between walls, a horn in which the space is filled with a filler, and
a method of manufacturing the same, wherein as described above, a large amount of horns with
excellent characteristics can be manufactured easily and conveniently, A low cost horn can be
Brief description of the drawings
FIG. 1 is a cross-sectional view of a mold apparatus used in a method of manufacturing a speaker
horn according to the present invention, FIG. 2 is a cross-sectional view during molding, and
FIGS. 3-a and 3-1] are manufacturing of the present invention. FIG. 4 is an enlarged sectional
view of a pin portion of a mold apparatus used in the method, and FIG. 4 and FIG. 5 are sectional
views of a speaker horn of the present invention.
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