JPS61222400A - Diaphragm for electroacoustic transducer - Google Patents

Abstract

PURPOSE:To obtain a diaphragm with high elasticity and with high loss by applying an organic or an inorganic matter etc. between fibers of a union cloth that are made of a high elastomer inorganic continuous fiber and an aromatic polyamide continuous fiber as a finding matter. CONSTITUTION:A 'Hi-carbolon(R)' as a carbon fiber and an aramid fiber as the aromatic polyamide fiber are used. An allocating quantity ratio for the union cloth is 50% of the carbon fiber and 50% of the aramid fiber. It is assumed that the weaving of the union cloth is performed by 4/1 satin weave. An used substrate (cloth) is impregnated by phenolic resin that is dissolved in methyl alcohol and after a hot air dry is applied, it is heated and pressurized with a metalic mold of 250 deg.C for 5 seconds and is formed as the diaphragm. At the next, ultraviolet ray curing type resin with viscosity of 5000cps is applied on the surface of the formed material for the purpose of the hardening and the filling of the material. As the result, it is possible to make a frequency characteristic better in the high frequency band sound area.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an imaging plate for an electroacoustic transducer having high elasticity and high loss.

(Summary of the Invention) The present invention provides a diaphragm for an electroacoustic transducer in which a bond or filler made of an organic substance, an inorganic substance, or a mixture thereof is added to a mixed woven fabric made of a highly elastic inorganic continuous 111M and an aromatic polyamide continuous fiber. By applying it, it has an elasticity of 8
This is an inexpensive version of the original diaphragm.

(Prior art and problems to be solved by the invention) Hitherto, speaker diaphragms have been made by molding plastic films, metal plates, woven fabrics, etc., or by paper-molding natural Il fibers or synthetic fibers. Many processed materials are used. However, these materials have a small elastic modulus, so it is not possible to obtain good frequency characteristics.

In order to improve these, glass fiber with high elasticity,
Inorganic ms such as carbon 1lli, silicon carbide orimai
Attempts have been made to improve the elasticity of the diaphragm using i.

However, since these inorganic fibers have small internal loss, it is difficult to obtain good frequency characteristics.

On the other hand, inorganic 1I such as carbon fiber and silicon carbide fiber
A diaphragm using aromatic polyamide fiber, which has a lower modulus of elasticity than M-thickness, but has a higher elasticity than M-threaded glass and has a larger internal loss, has also been attempted.

However, aromatic polyamide fiber (DuPont trade name Kevlar 4911vIi) has a lower Young's modulus than carbon 1IIll and has a low heat resistance temperature of 204° C., so it has the disadvantage that it is easily deformed during hot molding.

(Means for Solving the Problems) The present invention was proposed to eliminate the shortcomings of the first harp.
Highly heat resistant, highly elastic inorganic fiber and aromatic polyamide l1I
It is characterized by forming an intermixture of II & and bonding the fibers with an organic or inorganic substance, and its purpose is to provide a diaphragm with high elasticity and 1% loss in the field.

Inorganic fibers that can be used in the present invention include elastic inorganic continuous fibers such as carbon fibers and alumina fibers. Further, as the aromatic polyamide fiber, heat-resistant continuous fibers such as aramid fiber (Kevlar 49) and Nomex (trade name, manufactured by DuPont) can be used.

The interfiber bonding material may be an organic substance such as phenol resin, epoxy resin, or acrylic resin, or an inorganic binder that can be cured at 150°C for 20 minutes (product name: Kanbe CELA).
: Lit Nishi Paint Co., Ltd.) can also be used.

As the interfiber bonding and sealing material, not only the above-mentioned organic substances and amorphous substances, but also synthetic resins mixed with finely powdered graphite or the like can be used.

As the mixed woven fabric serving as the base material of the diaphragm, woven fabrics such as plain weave, twill weave, and satin weave can be used. It is also possible to change the physical properties by changing the number of fibers, thread thickness, blending ratio, etc.

Next, the present invention will be explained in detail. Note that the embodiments are merely illustrative, and it goes without saying that various changes and improvements can be made without departing from the spirit of the invention.

(Example) A case will be described in which a mixed woven fabric is made using carbon fibers and aromatic polyamide fibers, and this is used as a diaphragm base material.

The carbon fiber used was old-carbolon (trade name of Asahi Nippon Riki-Pon Fiber Co., Ltd.), and the aromatic polyamide MS was aramid m-thread (Kepler 49: trade name of DuPont Co., Ltd.). The amount of fiber used in the mixed fabric was 50% carbon fiber and 50% aramid II miscellaneous.

The weaving method of the mixed fabric was 4-ply satin weave. Table 1 shows the composition of the base material (III material) used. Its structure is as shown in Fig. 1, where 1 indicates carbon fiber and 2 indicates aramid 5aei.

Table 1 The physical properties of the carbon ra metal used here are as shown in Table 2.

Table 2 The physical properties of the aramid fibers used here are as shown in Table 3.

Table 3 The above base material was impregnated with phenol resin dissolved in methyl alcohol, and after drying with hot air 1 #i, it was heated and pressed in a mold at 250°C for 5 seconds to form a shape with a diameter of 20 cm + diaphragm. .

Next, an ultraviolet curable resin 5c-100 (trade name, manufactured by Denki Kagaku Kogyo Co., Ltd.) having a viscosity of 5000 cps is applied to the surface of the molded base material for the purpose of reinforcing the base material and filling it.

It is necessary to cure the resin quickly, but these 5
O-100 is cured with irradiation energy of 6000 J (millijium), so when using a high-pressure mercury lamp,
The irradiation time was 20 seconds for complete curing.

Figure 2 shows the frequency characteristics. In the figure, A is a paper-made diaphragm, and B is a diaphragm of the present invention. From these characteristics, it is recognized that the present invention has excellent characteristics, particularly in the high frequency range.

(Effects of the Invention) As described above, the present invention is characterized in that a cross-woven fabric made of elastic inorganic continuous fibers and aromatic polyamide continuous woven fabric is bonded or filled with an organic substance, an inorganic substance, or a mixture thereof. As a result, it has high elasticity, high loss, and sis&! I
You can move around a diaphragm with excellent i-number characteristics.

[Brief explanation of the drawing]

FIG. 1 shows the structure of the diaphragm base material, and FIG. 2 shows the frequency characteristics. 1...Carbon fiber, 2...Aramid m tape Patent applicant Foster Electric Co., Ltd. Figure 1 Figure 2 J115 skin (Hz)

Claims (1)

[Claims] A diaphragm for an electroacoustic transducer, characterized in that a woven fabric made of highly elastic inorganic continuous fibers and aromatic polyamide continuous fibers is bonded or filled with an organic substance, an inorganic substance, or a mixture thereof.