JPS60182298A - Production method of acoustic diaphragm - Google Patents

Abstract

PURPOSE:To produce a patterned-sheet diaphragm by press-contacting a patterned plate which has heated meshes onto the surface of a sheet such as a thermoplastic resin, softening the sheet to form uneven patterns on the sheet, and by shaping it with a mold into an acoustic diaphragm. CONSTITUTION:A sheet C such as a thermoplastic resin is mounted on a female mold A, a press-contacting mold B is dropped, and a pattern plate B is press- contacted on the sheet C. A heat press-contact part B1 is heated up to the required temperature, thereby warming up a press-contact type B2, and forming uneven patterns corresponding to the unevenness of the pattern plate B2 on the sheet C surface, at the same time softening also the sheet C by warming it up. Where air inside a hollow A1 is extracted out of the female type A and the sheet C softened by this vacuum pressure is closely attached to the side wall of a hollow A1 of the female A and is shaped in the same form as the hollow A1. And by raising the pressing type B and taking out the sheet C, the mesh patterns corresponding to, for example, meshes of the pattern plate B2 are formed on the cone-shaped sheet C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a method of manufacturing an acoustic diaphragm such as a cone diaphragm for a speaker.

[Technical background of the invention and its problems] Conventionally, the materials for acoustic diaphragms such as cone diaphragms for speakers have been thermoplastic resins without the addition of fillers, or mica, talc, carbon, and carbon fibers. A number of diaphragms have been invented in which diaphragms are molded into diaphragms mixed with some kind of filler.

In particular, acoustic diaphragms containing mica and carbon graphite have a ratio of Young's modulus E to density ρ! was large, and had fairly excellent acoustic characteristics.

However, for such acoustic diaphragms, only one type of molded product can be obtained using the same molding die and molding material, and in order to obtain various external designs, different molding molds must be used for each design. Since a mold is required, the number of molds required is large, and the depreciation costs are high, so the cost of the acoustic diaphragm is high, and this method is not satisfactory as a manufacturing method for acoustic diaphragms. Ta.

[Purpose of the invention]

The present invention forms a pattern such as a mesh pattern or a punching pattern on the surface of an acoustic diaphragm, and by changing this pattern, it is possible to supply acoustic diaphragms with many designs using one type of molding die. Therefore, mold depreciation cost does not increase, cost I
- The purpose of the present invention is to obtain a method for manufacturing an inexpensive acoustic diaphragm.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

For example, mica, thermoplastic resin such as polyethylene,
Mixing fillers such as talc, carbon, and carbon fiber,
Alternatively, a single thermoplastic resin is rolled into a sheet at a sheet forming temperature suitable for the thermoplastic resin to form a sheet with a desired thickness.

The first mold is used to mold this sheet into the required diaphragm shape.
As shown in the figure, the female mold A is a vacuum molding mold in which a cavity A1 having the same shape as a cone-shaped diaphragm is formed.

The pressing mold B is one in which a pattern plate B2 such as a wire mesh or a metal plate punched with holes of a desired shape is attached to a heating pressing part B1 that is heated to a required temperature with heated steam or electric heat, etc. This pattern board B2 can be replaced depending on the pattern to be formed.

The sheet C is placed on top of the female mold A, and the second
As shown in the figure, the pressing die B is lowered to press the pattern plate B onto the sheet C.

Since the heating press part B+ of the press mold B2 is heated to the required temperature as described above, the pattern plate B2 is also heated to this temperature, and the pattern plate B2 is heated to the upper surface of the sheet 1-C by this temperature. At the same time as forming an uneven pattern corresponding to the unevenness, the sheet C is also warmed and the sheet C is softened.

At this time, the air in the cavity A+ of the female mold A is extracted by a pump, and the seal is softened by this vacuum pressure.
-C is in close contact with the wall surface of the cavity A1 of the female mold A, as shown in FIG. 3, and the sheet C is molded into the same shape as the cavity A1.

After forming the patterned LJ and the sheet C on the sheet C in this way, as shown in FIG. 4, the pressing die B is raised to take out the sheet and C. As shown in FIG. 5, a mesh pattern corresponding to, for example, the wire mesh H of pattern board B2 is formed on the surface of C.

Therefore, the pattern board B2 can be made of a wire mesh in which vertical and horizontal wires are alternately exposed on the surface, as well as a different knitting, that is, the sixth and first plain weave, the seventh
Use the tatami weave shown in the figure, the twill weave shown in figure 8, the triple weave wire mesh shown in figure 9, or use the metal plate with round holes, square holes, and slotted holes as shown in figures 10 to 15. Accordingly, the design of the surface of the sheet t-c can be changed to correspond to these irregularities.

Alternatively, it is also possible to partially incorporate such patterns.

In addition, for the pressing type B, instead of attaching the pattern plate B2 to the heating pressing part B1, it is also possible to carve a pattern such as a mesh pattern or a punching pattern on the sheet pressing surface of the heating pressing part B+, and the same effect can be obtained. is obtained.

〔Effect of the invention〕

As described above, in the present invention, a heated pattern plate having mesh patterns, punching patterns, etc. is pressed onto the surface of a thermoplastic resin or a thermoplastic resin sheet mixed with a filler, and the sheet is softened to create the pattern. Since a concavo-convex pattern corresponding to the sheet is formed on the sheet and at the same time molded into the required shape as an acoustic diaphragm using a molding die, the concavo-convex pattern formed on the sheet can be changed by replacing the pattern plate. .

Therefore, the uneven pattern can be changed extremely easily depending on the purpose or design, and since a variety of purposes and designs can be achieved with a single mold, the number of molds required can be reduced, which reduces mold depreciation. The cost is reduced, making it possible to reduce the cost of the acoustic diaphragm.

Furthermore, the uneven pattern such as mesh or punched lines has a reinforcing effect on the diaphragm, and if this uneven pattern has a shape with ribs or corrugations, the reinforcing effect is particularly strengthened and the acoustic characteristics can be improved. .

For example, as shown in FIG. 16, in a woofer using a cone-shaped diaphragm of the same shape, the conventional frequency characteristic as shown in a is improved as shown in b when the present invention is implemented.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIGS.
The figure is a sectional view showing the molding process, Figure 5 is a front view of the product, Figures 6 to 15 are plan views showing the types of pattern plates, and Figure 16 is an acoustic diaphragm implementing the present invention. FIG. 3 is a frequency characteristic diagram of a conventional acoustic diaphragm. A...Female type, A1...Cavity, B...
...Press mold, B1...Heating press part, B2...
...Pattern board, C...Sheet. Patent applicant Pioneer Co., Ltd. Mogami Electric Co., Ltd.

Claims (1)

[Claims] After rolling and molding a diaphragm material made of a thermoplastic resin or a thermoplastic resin mixed with a filler such as mica, talc, carbon, carbon fiber, etc. to form a sheet, mesh patterns, punching patterns, etc. are formed on one side of the sheet. An acoustic device characterized in that the heated patterned plate is press-welded to form a pattern such as a mesh pattern or a punched pattern, and at the same time, the sheet is molded into a desired diaphragm shape such as a cone shape using a molding die. Method of manufacturing a diaphragm for use.