JPS625518B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a speaker diaphragm that can produce a speaker diaphragm with excellent rigidity and good moldability, and in particular, by using a base fabric of silicon carbide fiber, it is possible to manufacture a speaker diaphragm with uniform thickness and physical properties and a thin speaker diaphragm. This makes it possible to provide a diaphragm. Conventional diaphragms for speakers having high elasticity include those using titanium foil or aluminum foil, and recently those using beryllium foil have been put into practical use. However, speaker diaphragms made of titanium foil or aluminum foil have sufficient rigidity.
Although speaker diaphragms using beryllium foil have excellent rigidity, they are difficult to mold, extremely expensive, and have problems in terms of the working environment, such as pollution. It had some flaws. The present invention aims to provide a method for manufacturing a speaker diaphragm that eliminates the above-mentioned conventional drawbacks. Embodiments of the present invention will be described below with reference to FIGS. 1 to 6. That is, in the present invention, tens to hundreds of silicon carbide fibers of 8 to 12 microns are made into one bundle, and this is plain-woven to form the base fabric 1 shown in FIGS. 1 and 2. FIG. 1 is a top view of the base fabric 1, and FIG. 2 is an enlarged sectional view of the main parts of the base fabric 1. This base fabric 1 is impregnated with polycarbosilane 2 dissolved in a benzene solution as shown in Figs ^.
The diaphragm body 3 is then molded into a diaphragm shape as shown in FIG. 5 by heating and pressurizing. This diaphragm element 3 is gradually heated in an oxygen-free or inert gas atmosphere, and fired and carbonized at a high temperature of 1000°C to 1500°C, resulting in a speaker diaphragm 4 shown in FIG.
get. This polycarbosilane 2 undergoes a gradual polycondensation reaction and hardens at a temperature of 300℃ to 800℃.
Silicon carbide begins to crystallize at a temperature of 1000°C to 1500°C, and is firmly bonded to the silicon carbide fiber base fabric 1.
A speaker diaphragm 4 with excellent rigidity can be obtained. The impregnation ratio of polycarbosilane 2 to the silicon carbide fiber base fabric 1 is 60 to 80 wt%.
On the other hand, 20 to 40 wt% of polycarbosilane 2 is effective. In addition, the conditions for calcination carbonization are as follows:
The temperature is gradually raised to 300°C to 800°C, and in the remaining 3 to 4 hours, the temperature is raised to a high temperature of 1000°C to 1500°C to carbonize. Next, the table below shows test results regarding the physical properties of a conventional speaker diaphragm made of aluminum, titanium, and beryllium, and a speaker diaphragm manufactured by the above-described method of the present invention.

[Table] Also, the speaker diaphragm obtained by the method of the present invention has a higher silicon carbide content than the speaker diaphragm obtained by simply molding a mixture of silicon carbide fibers with polycarbosilane and firing and carbonizing it. Because the fiber base fabric is uniform throughout, the physical properties such as rigidity are uniform throughout, and when used as a speaker, no split resonance occurs, and it also has excellent tensile strength. Therefore, it has the new effect of being able to be formed even thinner. As described above, according to the method for manufacturing a speaker diaphragm of the present invention, a speaker diaphragm that has excellent rigidity, is stable in terms of quality, and is thin and lightweight can be manufactured with good moldability. It can be applied to any shape, including shapes, and is advantageous in terms of cost.
It does not pose any environmental problems such as pollution during manufacturing, is highly safe, and has great industrial value.

[Brief explanation of the drawing]

Fig. 1 is a top view of the silicon carbide fiber base fabric used in the method for producing a speaker diaphragm of the present invention, Fig. 2 is an enlarged sectional view of the same main part, and Fig. 3 is the same base fabric impregnated with polycarbosilane. Fig. 4 is an enlarged sectional view of the same essential parts, Fig. 5 is a half sectional view of the same material molded into a diaphragm shape, and Fig. 6 is a sintered carbonized diaphragm body of the same diaphragm. FIG. 3 is a half-sectional view of the speaker diaphragm. 1... Silicon carbide fiber base fabric, 2... Polycarbosilane, 3... Diaphragm element, 4... Speaker diaphragm.

Claims (1)

[Claims] 1 Impregnating a base fabric made of silicon carbide fiber with polycarbosilane and molding it into a diaphragm shape,
A method for producing a diaphragm for a speaker, which comprises gradually raising the temperature of this diaphragm element in an oxygen-free environment or in an inert gas, and firing and carbonizing the diaphragm body at 1000°C to 1500°C.