JPS6360600B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a speaker diaphragm having a sandwich structure, and is capable of preventing deformation of the skin material due to changes in air pressure, temperature, etc., such as deformation of the skin material that occurs when the skin material and core material are bonded together. The purpose is to eliminate it.

Conventional Structures and Their Problems In recent years, speaker diaphragms that use a sanderch structure in which skin materials are bonded to both the front and back sides of a lightweight, highly rigid core material have been developed. A speaker diaphragm having this sanderch structure is characterized by greater bending rigidity than a conventional cone-shaped speaker diaphragm composed of a single sheet.
Therefore, the piston movement range of the diaphragm is expanded, and the reproduction band can be extended. Furthermore, since the sound radiation shape is flat, it is possible to eliminate disturbances in the sound pressure-frequency characteristics caused by the front chamber effect that occurs with cone-shaped speakers.

Generally, a honeycomb structure made of alloy foil such as aluminum (hereinafter referred to as a honeycomb core) is used as the core material of the sandwich structure, and a highly elastic sheet material such as aluminum alloy foil or carbon graphite is used as the skin material. .

The present inventors previously proposed a speaker diaphragm 1 in which a thermoplastic resin film as shown in FIG. 1 was used as the core material instead of the 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. This core material 2 has a large number of frame-shaped protrusions arranged continuously in the radial direction on one surface, and has linear protrusions arranged in the radial direction on the other surface at the bottom of each of the frame-shaped protrusions. It is a structure. A speaker diaphragm 1 using this core material 2 is manufactured as follows.

First, a concave mold 6 having a rectangular protrusion shown in FIG. 2 is created. Further, as shown in FIG. 3, a convex mold 7 having a radial and plate-shaped plug placed at the center of the cell of the concave mold 6 is made to form a part to be bonded to the skin material 4 on the back side. next,
As shown in Fig. 4a, the uneven molds 6 and 7 are attached to
Set above and below. Then, when the film 8 is heated and pressed with the uneven molds 6 and 7, it is formed into an uneven shape as shown in FIG. 4b, and the core material 2 is obtained.

As shown in FIG. 5, the core material 2 thus obtained is sandwiched between a skin material 3 on the front side, a sheet-like hot melt adhesive 5, and a skin material 4 on the back side, and pressed with hot plates 9 and 10 to form an adhesive. is melted once, then immediately cooled and solidified to adhere.

However, in the case of the core material as shown in FIG. 1, the cells 2a and 2b are each independent, and the skin material 3
It is isolated from the outside air by. For this reason, when the skin material is cooled after being pressed with a hot plate, the air inside the cell contracts and the skin material dents due to the difference in air pressure with the outside. FIG. 6 is a cross-sectional view of the cell. When a dent occurs in the skin material in this way, when a bending moment is applied as shown in Figure 7, tensile stress moves to the skin material 3, and the skin material 3 easily bends until the dent disappears, which shows that the rigidity is very small. This has the disadvantage that the resonant frequency of the speaker diaphragm decreases and the reproduction band becomes narrower.

In addition, changes in the volume of air inside the cell due to changes in external air pressure or changes in temperature after bonding also cause unevenness in the skin material, and if this is repeated, the bonded area will become fatigued and the skin material will deteriorate. Problems arise in which the core material peels off or the diaphragm warps.

OBJECTS OF THE INVENTION The present invention provides a speaker diaphragm with a sanderch structure that solves the problems of the speaker diaphragm using the above-mentioned plastic core material, and a method for manufacturing the same.

Structure of the Invention The present invention has grooves connecting the cells to a large number of frame-shaped protrusions that are continuously arranged on one surface, and linear protrusions that are arranged in the radial direction at the bottom of the frame-shaped protrusions on the other surface. A core material having the structure is molded from plastic film, skin materials are arranged on both the front and back sides of this core material, and this core material is bonded to the frame-shaped protrusion and the linear protrusion. Therefore, the above-mentioned conventional problems can be solved.

DESCRIPTION OF EMBODIMENTS FIGS. 8 and 9 are cross-sectional perspective views showing a mold for molding a core material and a portion of the core material in an embodiment of the present invention. In FIG. 8, 11 is a concave type having a rectangular frame-like protrusion, and cells 11e, 1
Grooves 11c, 11d, 1 are formed in the radial protrusion of 1b.
Make 1e. When this concave mold 11 is replaced with the concave mold 7 shown in FIG. 4 and a film is press-molded, the convex mold 6 forms grooves 11c, 11d,
1e, grooves 12c, 12d, and 12e can be formed in the frame-shaped protrusion of the core material 12, 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 front skin material is bonded to the core material according to this embodiment, the cells are connected to the outside through the grooves, so the skin material does not deform due to changes in air pressure or temperature. The decrease in stiffness seen in the above does not occur.

Other embodiments of the present invention will be described below based on the drawings. FIGS. 10 and 11 show a concave mold for molding the core material and the core material in this embodiment. The concave mold 13 shown in FIG. 10 has one groove 13a on the outermost protrusion, and grooves 13b similar to that in FIG. 7 on all the inner radial protrusions.
13c is provided. Furthermore, grooves 13d and 13e are provided all around the circumferential protrusion of at least one cell set among the radial cell sets. When this concave mold 13 is replaced with the concave mold 7 shown in FIG. 4 in the same manner as in the previous embodiment, a core material 14 shown in FIG. 11 is obtained.

As described above, even if the skin material is bonded to the core material according to this embodiment, the cell is connected to the outside through the groove, so the skin material is damaged by the expansion and contraction of the air inside the cell caused by changes in air pressure and temperature. No dents or bulges occur, and the rigidity of the diaphragm does not decrease. In addition, when used as a diaphragm, in the first embodiment, many grooves are visible on the outer periphery, but in this embodiment, there are only four grooves.
Only part a can be seen, which is good from an aesthetic point of view.

Further, in the above two embodiments, the shape of the cell is a quadrilateral, but it may be any other polygonal shape, or any frame shape.

Effects of the Invention Generally, a hot melt adhesive or a thermosetting adhesive is used to bond the core material and the skin material. When the skin material and core material were heated during bonding, and then cooled and removed, the air in the cells sealed by the core material and skin material contracted, causing a large dent in the skin material and reducing the rigidity of the diaphragm.

According to the present invention, grooves are formed in the protruding part of the concave mold for molding the core material, and grooves are formed between the cells of the core material and the protruding part on the outermost periphery of the core material during molding. can be connected. Since this groove makes the air pressure of the cell and the outside air the same, it is possible to eliminate the dent in the skin material that occurs when the skin material and the core material are bonded together by heating. In addition, it is possible to prevent a decrease in the rigidity of the diaphragm due to deformation of the skin material due to the expansion and contraction of the air inside the cell caused by changes in atmospheric pressure and temperature, thereby preventing a decrease in the reproduction band of the speaker. be able to.

In addition, with conventional speaker diaphragms, repeated stress is applied to the bonded parts due to changes in air pressure and temperature, causing the skin material and core material to separate, but this problem can also be resolved with the present invention, resulting in improved reliability. Great effect can be obtained.

[Brief explanation of drawings]

Figure 1 is a cutaway perspective view of the main parts of a diaphragm with a Sanderch structure using a conventional core material,
FIG. 3 is a cutaway perspective view of the main part of the concave mold for molding the conventional core material shown in the figure, FIG. 3 is a cutaway perspective view of the main part of the convex mold for molding the conventional core material, and FIGS. FIG. 5 is a diagram showing the bonding process of the core material and skin material, FIG. 6 is a cross-sectional view showing the skin material in a deformed state, and FIG. 7 is a diagram showing the process of forming the core material shown in FIG. FIG. 8 is a cross-sectional view showing a state in which a bending moment is applied to the diaphragm; FIG.
The figure is a cutaway perspective view of the main part of the core material of the first embodiment, FIG. 10 is a cutaway perspective view of the main part of the concave mold for molding the core material of the second embodiment of the present invention, and FIG. 11 is the above-mentioned FIG. 7 is a perspective view of a main part of a core material according to a second embodiment; 1... Vibration plate, 2... Core material, 3, 4... Skin material, 5... Sheet adhesive, 6, 7... Molding mold, 8... Film, 9, 10... Hot plate, 11 ，
13... Molding mold, 12, 14... Core material, 2a,
2b, 11a, 11b...Cell, 11c, 11
d, 11e, 12c, 12d, 12e, 13a,
13b, 13c, 13d, 13e...grooves.

Claims (1)

[Claims] 1. One surface has a large number of continuously arranged grooved frame-like protrusions, and the other surface has linear protrusions arranged radially at the bottom of each of the frame-like protrusions. A speaker diaphragm comprising a core material made of plastic, and skin materials disposed on both the front and back surfaces of the core material and bonded to the frame-shaped protrusion and the linear protrusion. 2. A core material having a large number of continuously arranged grooved frame-shaped protrusions on one surface and linear protrusions arranged in a radial direction at the bottom of each of the frame-shaped protrusions on the other surface. It is constructed by molding a plastic film into a concave type having a grooved protrusion corresponding to the frame-like protrusion, and a convex type with a plug placed at a position corresponding to the center of each protrusion. A method for manufacturing a speaker diaphragm, characterized by bonding skin materials on the front and back sides.