JPS5839440B2 - Diaphragm for speaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speaker diaphragm that is lightweight, has high rigidity, and has excellent moldability.

Conventional speaker diaphragms with high elasticity include those using metal foils such as titanium, beryllium, and aluminum.

However, it is not possible to obtain sufficiently satisfactory rigidity and specific elasticity with titanium or aluminum, and products using aluminum have high rigidity and specific elasticity, but they have the drawbacks of being difficult to mold and extremely expensive. Ta.

The present invention aims to provide a speaker diaphragm that has high elasticity, is lightweight, and has excellent moldability in place of the speaker diaphragm using metal foil as described above.

Embodiments of the present invention will be described below with reference to FIGS. 1 to 7 of the drawings.

First, in FIG. 1, reference numeral 1 denotes a diaphragm body formed in a cone shape, and a free edge 2 is provided on the outer peripheral surface of the diaphragm body 1.
is attached to form a speaker diaphragm.

The diaphragm may be not only the cone-shaped diaphragm described above but also a dome-shaped or flat-plate diaphragm.

The diaphragm main body 1 as described above is formed by using a phenolic fiber 3 as a base material and impregnating the base material 3 with a phenolic resin 4, as shown in FIG.

The phenolic fiber 3 and the phenolic resin 4 have similar chemical structural formulas, and are strongly bonded as shown in the formula below during heat molding at 200 to 300°C.

When this is gradually heated in an oxygen-free or inert gas atmosphere and carbonized at a high temperature of 700°C or higher, the following structure is obtained.

The molded body 5 thus fired and carbonized is shown in FIG. 3, and on the surface of this molded body 50, as shown in FIG. After coating evenly and drying, 60
The SiIJ cone-boron-based inorganic polymer 6 is also carbonized at a high temperature of 0° C. or higher to form a SiC and boron carbide layer 7 on the surface of the molded body 50 to form a diaphragm substrate 1 as shown in FIG.
That is.

In addition, as shown in FIG. 6, phenolic fiber 3 impregnated with phenolic resin 4 was heated and molded at 200 to 300°C, and silicone was added to the surface as shown in FIG.
If a boron-based inorganic polymer 6 is uniformly applied, the temperature is gradually raised in an oxygen-free or inert gas atmosphere, and then fired and carbonized at a high temperature of 700°C or higher, a diaphragm substrate 1 as shown in Fig. 5 is obtained. can get.

That is, the present invention is characterized by a speaker diaphragm in which a carbonized layer 7 of a silicone-boron-based inorganic polymer is formed on the surface of a layer obtained by heat-forming phenolic fiber impregnated with a phenolic resin and then firing and carbonizing it. be.

The carbonized layer 7 of the silicone-boron-based inorganic polymer is in an amorphous state, and a speaker diaphragm having excellent physical properties can be obtained.

This silicone-boron-based inorganic polymer is commercially available as Big Bison (trade name: Special Inorganic Materials Research Institute).

Further, as the phenolic fiber 3, a novolak resin obtained by polycondensing a modified phenol such as phenol, cresol, or fluorophenol with an aldehyde typified by formaldehyde is used.

As the phenolic resin 4, a modified resin of phenol, cresol, or fluorophenol is used.

Furthermore, as the silicone-boron-based inorganic polymer 6, one synthesized by reacting diphenyldichlorosilane and a boric acid-based compound in an inert gas is used.

Such a speaker diaphragm of the present invention and conventional titanium,
The table below shows a comparison of the physical properties with a speaker diaphragm using BeiJIJum2 paper.

As an example of the present invention, a diaphragm to be compared with a conventional diaphragm was prepared as follows.

First, a phenolic fiber is used as a base material, and after being impregnated with a phenolic resin and molded, it is fired and carbonized at about 1200° C. in N2 gas.

Next, this molded product is uniformly coated with a silicon-boron based inorganic polymer on the front and back surfaces, and after drying, the temperature is raised in N2 gas and fired at a high temperature of 1200 to 13oO<0>C to obtain a diaphragm.

However, phenol carbide is 90-91wt%1. The content of the silicon-boron-based inorganic polymer is 9 to 10 wt%.

Furthermore, in the table, phenolic fiber decaphenolic resin carbide refers to a molded product of the diaphragm of the above example before being coated with a silicone-holon based inorganic polymer as a comparative example.

As the speaker diaphragm of the present invention is constructed as described above, it has physical properties comparable to beryllium, has moldability equivalent to that of a resin film, and is lightweight and highly rigid because it is sintered and carbonized. It can be used as a material and has great industrial value.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the speaker diaphragm of the present invention, Figs. 2 to 5 are sectional views of main parts in the manufacturing process of the diaphragm, and Figs. 6 and 7 are other views. FIG. 3 is a cross-sectional view of a main part of the manufacturing process of the example. 1... Vibration plate body, 2... Free edge, 3... Phenol fiber, 4...
Phenolic resin, 5...Carbonized fired molded product, 6
...Silicone-boron-based inorganic polymer, 7.
...Carbonized layer of silicone-boron-based inorganic polymer.

Claims (1)

[Claims] 1 Heat-molded phenolic fiber impregnated with phenolic resin is gradually heated in an oxygen-free or inert gas atmosphere and then fired and carbonized at a high temperature of 700°C or higher to form a silicone-boron-based material on the surface of the carbide. A speaker diaphragm characterized by having a carbonized layer of inorganic polymer.