JPS59190797

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DESCRIPTION JPS59190797
[0001]
TECHNICAL FIELD The present invention relates to a speaker diaphragm having a sandwich
structure, and it is an object of the present invention to eliminate the deformation of the skin
material due to the deformation of the skin material or the change of air pressure or temperature
which occurs when bonding the skin material and the core material. It is. 2. Description of the
Related Art In recent years, a speaker diaphragm using a sand-inch structure in which a skin
material is adhered to both the front and back sides of a lightweight and highly rigid core
material has been developed as a speaker diaphragm. A speaker diaphragm having this sand-ininch structure is characterized by having a large bending rigidity as compared with a
conventional cone-type speaker diaphragm constituted by a single sheet. Therefore, the piston
movement area of the diaphragm can be expanded and the reproduction zone can be extended.
Moreover, since the radiation shape of the sound is flat, it is possible to eliminate the disturbance
of the sound pressure-frequency characteristic due to the front room effect that occurs in the
cone type speaker. In general, a core material of a sand-inch structure is made of an alloy foil
such as aluminum, etc. · A nicam structure (hereinafter referred to as a honeycomb core), and a
skin material is a highly elastic sheet material such as an aluminum alloy foil or carbon graphite.
It is done. The inventors of the present invention have previously proposed a speaker diaphragm
1 using a thermoplastic resin film as shown in FIG. 1 as a core material instead of the abovementioned honeycomb core. In FIG. 1, 2 is a core material, 3 and 4 are skin materials, and 5 is a
sheet-like hot melt adhesive. The core member 2 has a large number of frame-shaped protrusions
continuously arranged in the radial direction on one surface, and has linear protrusions arranged
in the radial direction on the bottom of the respective frame-shaped protrusions on the other
surface It is a structure. The speaker diaphragm 1 using this core material 2 is manufactured as
follows. First, a concave 6 having a square projection shown in FIG. 2 is prepared. Further, as
shown in FIG. 3, in order to form a portion to be bonded to the back side skin material 4, a
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convex 7 having a radial and plate-like plug disposed so as to be at the center of the concave 6
cell is prepared. Next, as shown in FIG. 4a, the uneven molds 6 and 7 are set on the upper and
lower sides of the film 8. Then, when the film 8 is heated and pressed by the concavo-convex
molds 6 and 7, as shown in FIG. 4, the core material 2 is formed into a concavo-convex shape. As
shown in FIG. 6, the core material 2 thus obtained is sandwiched between the skin material 3 on
the front side, the sheet-like hot melt adhesive 5 and the skin material 4 on the back side 1 and
pressed with a heat plate 9.10 The adhesive is melted once and then immediately solidified by
cooling and bonding. However, in the case of the core material as shown in FIG. 1, the cells 2a
and 2b are independent of one another and are shielded from the outside air by the skin material
3.
For this reason, when the plate is cooled after being pressed by the hot plate, the air in the cell
shrinks and a phenomenon that the skin material dents due to the pressure difference with the
outside appears. FIG. 6 is a cross-sectional view of the cell. Thus, when a dent is generated in the
skin material, as shown in FIG. 7, when a bending moment is applied, a tensile stress is moved to
the skin material 3 and the rigidity is very high so as to be easily bent until the dent is eliminated.
The smaller the resonance frequency of the speaker diaphragm is, the longer the reproduction
frequency of the speaker diaphragm is. In addition, the skin material also has irregularities due to
changes in air pressure inside the cell due to changes in external air pressure or changes in
temperature after bonding, and when this is repeated, the bonded part is fatigued and the skin
and core material The problem of peeling off and the problem of deflection of the diaphragm
occur. SUMMARY OF THE INVENTION The present invention provides a speaker diaphragm
having a sand-in structure, which solves the problem of the speaker diaphragm using the abovementioned plastic core material, and a method of manufacturing the same. The present invention
has a groove connecting cells to a plurality of frame-like protrusions which are continuously
arranged on one surface, and on the other surface a linear protrusion which is aligned in the
radial direction on the bottom in the frame-like protrusion. The core material is molded with
plastic sock film, and skin materials are disposed on both the front and back sides of the core
material, and the core material is adhered to the frame-like protrusion and the linear protrusion.
Solves the above conventional problems. Description of the Embodiments FIGS. 8 and 9 are crosssectional perspective views showing a mold for molding a core material and a part of the core
material in one embodiment of the present invention. In FIG. 8, a cell 11e is a concave type 11
having a rectangular frame-like protrusion. Grooves 11c, 11d in the radial projections of 11b.
１１ｅをもうける。 When the concave mold 11 is replaced with the concave mold 7 of FIG. 4
and the film is press-formed, the convex mold 6 causes the film to form grooves 11c and 11d.
The grooves 12c, 12d and 12e can be formed in the core member 120 frame-like protruding
portion by being pulled into 11e and as shown in FIG. By providing these grooves throughout the
concave mold, grooves can be provided throughout the core material. As described above, even if
the skin material on the front side is adhered to the core weir according to this embodiment, the
cells are connected to the outside by the grooves, so deformation of the skin material due to
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changes in air pressure and temperature does not occur. Rigidity does not occur. Hereinafter,
another embodiment of the present invention will be described based on the drawings. . FIG. 10
and FIG. 11 show the concave mold and the core material for molding the core material in the
present embodiment.
The concave mold 13 shown in FIG. 1Q is provided with one groove 13a in the outermost
peripheral projecting portion, and the groove 13b similar to that in FIG. 7 is formed in all the
projecting portions in the inner radial direction. Provide 13c. In addition, grooves 13d and 13e
are provided over the entire circumference of the circumferential projection of at least one cell
set among the radial direction cell sets. If this concave mold 13 is replaced with the concave
mold 7 of FIG. 4 in the same manner as in the previous embodiment, the core material 14 shown
in FIG. 11 is produced. As described above, even if the skin material is adhered to the core
material according to the present embodiment, the groove is connected to the outside by the
groove, the expansion and contraction of the air in the cell caused by the change of the air
pressure and the temperature causes the dent of the skin material There is no swelling and no
reduction in the rigidity of the diaphragm. Still, when the diaphragm is used, in the first
embodiment, a large number of grooves can be seen in the outer peripheral portion and only the
grooves 14a can be seen in the present embodiment, which may be aesthetically pleasing.
Further, in the above two embodiments, the shape of the cell is a quadrangle, but any other shape
may be used as long as it is a frame shape. Effect of the Invention Generally, a hot melt adhesive
or a thermosetting adhesive is used to bond the core material and the skin material. At the time
of bonding, when the skin material and the core material were heated and cooled and taken out,
the air in the cells sealed between the core material and the skin material shrunk, the skin
material became large and the rigidity of the diaphragm was lowered. The present invention
forms grooves in the cells and cells of the core material and the cells and cells on the outermost
periphery at the time of forming by forming grooves in the projections of the concave mold for
forming the core material, and all the cells and cells of the core material It can connect the open
air. Since the air pressure of the cell and the outside air becomes the same by this groove, it is
possible to eliminate the dent of the skin material which occurs at the time of heat bonding of the
above-mentioned skin material and the core material. In addition, it is possible to prevent the
reduction of the rigidity of the diaphragm due to the deformation of the skin material due to the
expansion and contraction of the air in the cell caused by the change of atmospheric pressure
and the change of temperature, thereby preventing the reduction of the reproduction band of the
speaker. be able to. In addition, with the conventional speaker diaphragm, cyclic stress acts on
the bonded part due to changes in the id pressure and temperature, causing a problem of peeling
between the skin material and the core material. This problem can also be solved by the present
invention and reliability can be improved. Big effect can be obtained.
[0002]
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Brief description of the drawings
[0003]
FIG. 1 is a fragmentary perspective view showing a diaphragm having a sandwich structure using
a conventional core material, and FIG. 2 is a fragmentary perspective view of a concave portion
molding the conventional core material shown in FIG. 3 is a fragmented perspective view of the
main part of a convex mold for forming the conventional core material, and FIGS. 4a and 4b are
diagrams showing the core material forming process shown in FIG. 1, and FIG. 5 is a core
material and a skin material 6 is a cross-sectional view showing a deformed skin material, FIG. 7
is a cross-sectional view showing a state in which a bending moment is applied to the diaphragm
of FIG. 6, and FIG. 8 is the present invention FIG. 9 is a fragmentary cutaway perspective view of
the core member of the first embodiment, and FIG. 10 is a fragmentary perspective view of the
main portion of the concave member for molding the core member of the first embodiment. 11 is
a fragmentary cutaway perspective view of the core material of the second embodiment.
1······················································································
· · · · · · · · · · · · · · Mold · 8 · · · · · · · · · · · · · · · · · · · · · · · 11 + 13 · · · · · · · · · · · · · · · · · · · core material, 2a,
2b . １１ａ、１ｌｂ・−−−−−セル、１１Ｃ，１１ｄ、１１ｅ、１２ｃ、１２ｄ、１２ｅ、
１３ａ、１３ｂ。 13c, 13d, 13e ..... groove. Name of Agent Attorney Nakao Toshio and others 1
Figure 1 Figure 3 Figure 4 taJ tb Tabs Figure 5 Figure 6 Figure 7 Figure 9
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