JPS63287197A - Diaphragm for electro-acoustic transducer - Google Patents

Abstract

PURPOSE:To form a diaphragm with high elasticity and high loss having an excellent frequency characteristic by combining and packing an organic substance, an inorganic substance, etc., among the fibers of a union cloth consisting of a highly elastic continuous alumina ribber and an aromatic polyimide continuous fiber. CONSTITUTION:A union cloth is constituted of the highly elastic continuous fiber 1 whose elastic modulus is 10X10<3>kgf/mm<2> or higher having no electrical conductivity and an aromatic polyimide fiber, e.g., an aramide fiber 2. The organic substance, inorganic substance, or the mixture of the two are combined among the fibers. For the inter-fiber combination material, epoxy resin, phenol resin, acrylic resin, etc., can be used. For a woven cloth which is to be the base material of the diaphragm, a plain weave fabric, a trill fabric, etc., can be used. As a result, the diaphragm with high elasticity and high loss whose frequency characteristic is excellent having no electrical conductivity can be contained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a diaphragm for electroacoustic transducers that has no electrical conductivity, high elasticity, and n-loss.

(Summary of the Invention) The present invention provides an organic substance, an inorganic substance, or a mixture thereof between 5 isi of a mixed woven fabric made of high-modulus alumina continuous fibers and aromatic polyamide continuous fibers during imaging of an electroacoustic transducer. By bonding and filling the material, it has good electrical conductivity (and high elasticity, IR!), making it possible to hang a lossy diaphragm at low cost.

(Prior art and problems to be solved by the invention) Conventionally, speaker imaging plates have been made of plastic films, metal plates,
They are often made by molding woven fabric or the like, or by paper-forming natural fibers or synthetic fibers. However, since these have a small elastic modulus, it has not been possible to obtain good frequency characteristics.

In order to improve these, short fibers such as carbon fibers, aromatic polyamide fibers, and ceramic fibers having high elasticity are added to natural bulbs, and paper-formed bulbs are also used.

However, the above-mentioned high-modulus fibers have a weak bonding force with the valve, and due to the springback effect of the high-modulus m-thread, the amount of high-modulus fibers added to the valve fibers is limited to 10 to 15%. This is insufficient for improving elasticity.

However, in order to improve the elasticity of the imaging plate, attempts have been made to add short fibers such as carbon fibers, aromatic polyamide fibers, and ceramic fibers to thermoplastic resin;
% or more of short fibers has the disadvantage that manufacturing of the diaphragm becomes difficult and expensive.

On the other hand, attempts have also been made to bond and fill carbon SaW woven fabric with synthetic resin. In this case, it is possible to easily use a photographic plate containing 40% or more of carbon fiber.
Although it becomes a highly elastic diaphragm, it has the disadvantage that good circumferential loss characteristics cannot be obtained because the internal loss is small. Another disadvantage is that the lead terminal of the voice coil cannot be directly attached to the diaphragm because carbon m* has electrical conductivity.

In order to eliminate the above-mentioned drawbacks, attempts have been made to fabricate a diaphragm using a woven fabric of carbon fibers and organic high-elastic fibers. However, when attaching the voice coil lead terminal to the imaging plate, there are limits to the amount of carbon fiber that can be blended because carbon fiber has electrical conductivity, making it impossible to obtain a highly elastic and high-loss imaging plate. There is.

(Means for solving the problems) The present invention was proposed to eliminate the above-mentioned drawbacks.
The woven fabric is composed of highly elastic alumina continuous fibers and aromatic polyamide fibers that do not have electrical conductivity, and the fibers are bonded with an organic substance, an inorganic substance, or a mixture thereof, and its purpose is to conduct electricity. An object of the present invention is to provide a highly elastic and high-loss imaging plate having no conductivity at a low cost.

As the continuous alumina fibers that can be used in the present invention, those having the following physical properties can be used.

III diameter: 3-20. czm vAHI: 50cn+LJ upper specific gravity
= 2.6-3.9 Tensile strength: 10
0~250 KgL'mm2 Tensile modulus: 10~
40x103K (lL'1lli2 volume resistivity = 1
0I2 Ω-cm or more Furthermore, as the aromatic polyamide fiber, aramid fiber (Kevlar 49) or the like can be used.

The interfiber bonding material may be an organic substance such as epoxy resin, phenol resin, unsaturated polyester resin, acrylic resin, or vinyl chloride resin, or an a-type binder (product name: Kanbe CELA: Kansai) that can be cured at 150°C for 20 minutes. (manufactured by Paint Co., Ltd.) can also be used.

111 (as a spacing and sealing material, it is possible to use not only the above-mentioned organic and inorganic substances alone, but also synthetic resin mixed with finely powdered mica (particle size 50 to 350 mesh), etc.). be.

Fabrics such as plain weave, twill weave, and satin weave can be used as the intersecting material that serves as the limiting material of the micro-movement plate. It is also possible to change the physical properties by changing the number of threads, thread thickness, compounding ratio, etc.

Next, the present invention will be explained in detail. It should be noted 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 present invention.

(Example) The alumina continuous IIM used was Denka alumina long fiber (
The aromatic polyamide WAN is an aramid fiber (Kevlar 49: product name of Debon Co., Ltd.). The amount of fibers used in the mixed woven fabric was 50% alumina fiber and 50% aramid fiber by weight.

The weaving method of the mixed fabric was 4-ply satin weave. Table 1 shows the composition of the base material (fabric) used. Its structure is as shown in Figure 1, where 1 represents alumina continuous fibers and 2 represents aramid fibers.

Table 1 The physical properties of the alumina continuous fiber used here are as shown in Table 2.

Table 2 The physical properties of the Kevlar 49 fiber used here are as shown in Table 3.

Table 3 The above substrate was impregnated with a phenol resin dissolved in methyl alcohol, dried with hot air, and dried. It was heated and pressurized for 5 seconds in an O'C mold to form a diaphragm having a diameter of 20 cm.

Next, a UV-resistant resin 5c-100 (trade name, manufactured by Denki Kagaku Kogyo Co., Ltd.) having a viscosity of 5000 C11S 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
Since ci00 is cured with irradiation energy of 6000a+J (millijoules), when a high-pressure mercury lamp was used, it was completely cured in 20 seconds between irradiation and tJ4vg.

Figure 2 shows the frequency characteristics. In the figure, △ is a paper-making photographic board, and B is a photographic board of the present invention.From these characteristics, it is recognized that the present invention has excellent characteristics, especially in the high frequency range.

(Effects of the Invention) As described above, the present invention connects the fibers Ili of a mixed woven fabric made of high modulus alumina continuous fibers and aromatic polyamide continuous fibers with an organic substance, an inorganic substance, or a mixture thereof. , due to filling, it has high elasticity with no electrical conductivity.
A diaphragm with excellent loss and frequency characteristics can be obtained.

[Brief explanation of the drawing]

FIG. 1 shows the structure of the temporary imaging base material, and FIG. 2 shows the frequency characteristics.

Claims (1)

[Claims] The fibers of a mixed woven fabric made of alumina continuous fibers and aromatic polyamide continuous fibers having an elastic modulus of 10 x 10^3 Kgf/mm^2 or more are bonded and filled with an organic substance, an inorganic substance, or a mixture thereof. A diaphragm for an electroacoustic transducer characterized by: