JPS6076896A - Manufacture of diaphragm for speaker - Google Patents

Abstract

PURPOSE:To form a cone for a speaker having uniform thickness by putting sheetlike fiber reinforced resin material between heated silicone rubber and a forming die and pressing the silicone rubber into the forming die. CONSTITUTION:Sheetlike fiber reinforced resin material 5 containing 90W/W% or more of carbon fiber 0.2-1.0mm. in fiber length is placed on the forming die 6. Silicone rubber 7 is placed on it and pressed by a pressure plate 8. When pressing, the surface of the forming die 6 and silicone rubber 7 is heated beforehand at a uniform temperature. Thus, the resin material 5 is heated uniformly, stretched with the deformation of the silicone rubber, and formed to a cone 10 of uniform thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a diaphragm or vibrating member for Lisby force by thermoforming using a sheet material.

Conventional structure and its problems In general, paper cones are often used as speaker diaphragms, and ζh is due to the excellent physical properties of paper as a speaker diaphragm. Because of this, the thickness and density of the diaphragm are uniform for all i/i7s, which is a big advantage. However, the paper cone (I) has a complicated manufacturing process, poor productivity, and poor moisture resistance. jl
〆1. There is a drawback when the change over time is large.

In recent years, polymer composite 4AA, which is capable of continuous thermoforming, has good mass production, and has excellent environmental resistance, has been developed.
Among them, carbon fibers, aramid fibers, glass fibers, etc., made of high-quality thermoplastic resins containing carbon fibers, aramid fibers, and glass fibers (11) have properties superior to those of paper cones. A4I layout: It has been put into practical use because it is highly mass-producible.On the other hand, a disadvantage of thermoforming is that the thickness of the diaphragm after molding is inclined, resulting in the fh (high frequency limit) of the speaker. There was a drawback when there was a decrease or variation in 4!J property.The conventional molding method for this type of cone is shown in Figure 1. 01 is the first mold, 2 is the first mold of the same type as 1. This is the second mold, and is used to cold-press and mold the molded material 3, which has been heated to an appropriate temperature in advance, and the molded product tends to become thinner toward the center.A representative example is shown in Figure 2. A cross-sectional view of a typical molded product is shown.

As shown in FIG. 2, the thickness of the outer periphery of the cone 4 is approximately the same as before molding, but the thickness of the central portion is 60 to 80 inches thicker than the outer periphery, depending on the depth of the cone. When the central portion becomes thin in this manner, the rigidity of the diaphragm is reduced, and when a voice coil is coupled to the central portion and driven, the fh of the speaker is reduced.

If this sheet-shaped fiber-reinforced resin was thermoformed using conventional methods, mass production would be improved, but the material's inherent physical properties could not be utilized effectively as speaker characteristics. .

In order to solve these problems, a sheet of fiber-reinforced resin material is placed between a low-hardness silicone rubber heated above the melting point of the resin and a mold heated to the same temperature.
A molding method has been devised in which this is pressurized and silicone rubber is forced into the mold. In this way, the fiber-reinforced resin material 1.first comes into contact with the surface of the silicone rubber and is heated uniformly, and when pressurized, 7. it stretches as the silicone rubber deforms, making the thickness of the molded product almost uniform. I can do it.

However, there was a drawback in that the fiber length of the fibers mixed as a reinforcing material had a -15 influence on molding, strength, and physical properties after molding. That is, if the fiber length is too long, it becomes difficult to stretch the fibers evenly, and if it is too short, the physical properties of the material deteriorate.

OBJECTS OF THE INVENTION The object of the invention is to eliminate the above-mentioned drawbacks of the conventional technology, and to provide a method for manufacturing a diaphragm that can effectively exhibit the physical properties of the material with a uniform thickness.

+14 ADVANTAGE OF THE INVENTION The method for producing a diaphragm of the present invention is to heat the sheet-shaped fiber reinforced resin material 1-1 containing reinforcing fibers with a defined fiber length to a temperature higher than the melting point of the resin, and to produce a material having the same hardness as low hardness silicone rubber. The silicone rubber is placed in the middle of a heated mold and pressurized to force the silicone rubber into the mold.

In this way, the fiber-reinforced resin material first comes into contact with the surface of the silicone rubber and is heated uniformly, and when pressurized, the material is molded as the silicone rubber deforms. At this time, since the fiber length of the reinforcing fibers is regulated, it can be molded to a uniform thickness, and all the physical properties of the fiber can be effectively exhibited.

Description of examples Examples of the present invention will be described below.

Figure 3 shows the first embodiment of the present invention, in which carbon fiber '6 has a fiber length of 0.2 to 1.0I+II+1 (diameter 6
This fiber-reinforced resin material is made by cutting a 200 μm thick sheet of polyethylene containing 90 W/W% or more of 1Im) into the required size in advance, and placing it on a mold 6 and placing a low hardness film on top of it. 7 Recon rubber 7 (Rubber hard IK6: Toren Recon Co., Ltd. 911) X-35-063
) is placed and pressurized together with the presser plate 8.

This pressurization is performed within the cylinder 9 in order to prevent the silicone rubber 7 from flowing out. Also, mold 6 and 7 recon rubber Y
surface is heated to a uniform temperature. This 1. The fiber-reinforced resin 4'A is heated uniformly and stretches as the silicone rubber 7 deforms, resulting in a molded product with a uniform thickness. 4J is given.

Fig. 214 shows cone 1 molded by the manufacturing method of this example.
0 is shown. Outer periphery 10a and inner periphery 1 of cone 10
0b + = JL molded with precision within ±6%,
It is possible to create a diaphragm that effectively exhibits the effects of the moon.

Figure 5 shows the fiber length of the carbon fibers mixed in and the Young's modulus after heating.

FIG. 6 shows the relationship between the fiber length and the sheet elongation (elongation rate just before breaking) in each case.

From Figures 5 and 6, it can be seen that when the fiber length is less than 0.2 Tmn, the Young's modulus decreases, and when the fiber length exceeds 1.0 mm, the monthly elongation rate decreases and the formability tends to decrease. . Therefore, the fiber length should be set to 0.2 to 1.0++ lI.
By setting it within the I+ range, moldability is good and deterioration in physical properties can be minimized.

FIG. 7 shows an example of a speaker diaphragm obtained by the method of the present invention.

In FIG. 7, the core material has the shape of a plurality of fan-shaped small pieces having a zigzag cross section by 12t, and surface strips 11a and 11b are attached to both sides of the core material to form a diaphragm for a flat speaker. It consists of

Norino 1-1 is molded using a mold of the same shape as Shingetsu 12Il-i, using a method exclusively developed by Nikki Jitsusagi, and allows complex shapes to be molded in one piece in a short amount of time. . 'This 1
．． Currently, expensive flat diaphragms can be manufactured at low cost, and the quality of the casing is also stable.

Effects of the Invention As described above, according to the present invention, it is possible to mold a sheet-like fiber-reinforced resin material into a uniform thickness, which was previously difficult to mold to a uniform thickness, and it is possible to mold a sheet-like fiber-reinforced resin material into a uniform thickness. It can be molded into a cone shape.

By applying it to +L4J, such as a dome-shaped diaphragm or a dust cap, or a sandwich-structured flat plate imaging plate, it is possible to utilize up to one product per month.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing a conventional molding method, Fig. 2 is a schematic diagram of a diaphragm formed by a conventional method, Fig. 31 is a cross-sectional view showing an embodiment of the molding method according to the present invention, and Fig. 4 is a cross-sectional view showing an embodiment of the molding method according to the present invention. IIJi side view of the diaphragm formed by the method of the present invention, No. 51 Δt
", Diagram showing the relationship between fiber length and Young's modulus of reinforcement A1, No. 6
The figure shows the relationship between fiber opening &ft length and elongation rate of material, No. 7
Figure (l) shows an example of a diaphragm for a speaker made by the method of the present invention, but is partially cut away (this is a partially cutaway diagram). 6 Press t4L 1o Cone. Name of agent] 1゛ Burial officer Toshi Nakao and 1 other person Fig. 1 Fig. 2r54 Fig. 3 Fig. 4 Fig. 5 Fig. 5 Itosoko (InlTll Fig. 6! d1 length CrnrQ) Figure 7

Claims (1)

[Claims] A sheet of fiber-reinforced resin obtained by mixing high elastic fibers such as carbon fibers, aramid fibers, and glass fibers with synthetic resin fibers for reinforcement is heated with heated silicone rubber and molded into a mold. Place the silicone rubber in the middle of the reinforcing fibers and press the silicone rubber into the mold by applying pressure n to L.
A method for manufacturing a speaker diaphragm, characterized in that at least % of the fibers have a fiber length of 0.2-1.0 mm.