JPS63287196A - Diaphragm for electro-acoustic transducer - Google Patents

Abstract

PURPOSE:To realize a diaphragm with high elasticity and high loss whose frequency characteristic is excellent by constituting a woven cloth with a highly elastic continuous alumina fiber and another highly elastic fiber, and combining among the fibers with an organic substance, inorganic substance, or others. CONSTITUTION:The woven cloth is constituted of a highly elastic continuous alumina fiber 1 having an elastic modulus of 10X10<3>kgf/mm<2> or higher and another high elastic fiber, e.g., silicone carbide mixed fiber spinning. And an organic substance, an inorganic substance, or the mixture of these substances are packed among the fibers to combine them. For this inter-fiber combination material, an epoxy resin, a phenol resin, or others 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 obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a high-elasticity, high-loss electroacoustic transducer [Jl plate] that does not have electrical conductivity.

<Summary of the Invention) The present invention comprises a woven fabric made of highly elastic alumina continuous fibers and a fibrous material in a diaphragm of an electroacoustic transducer, and the fibers are made of organic material, inorganic material, or these materials. By bonding and filling with the mixture, a diaphragm with electrical conductivity, high elasticity, and high loss can be obtained for safety and security.

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

Therefore, in order to improve the elasticity of the imaging plate, attempts have been made to add short fibers such as charcoal 1AII fiber, aromatic polyamide fiber, and ceramic fiber to the thermoplastic resin.

However, if 40% or more of short fibers are added to the resin, there is a drawback that it becomes difficult to manufacture a photographic plate.

On the other hand, attempts have also been made to use carbon fiber woven fabric or nonwoven fabric bonded and filled with synthetic resin. In this case, 4
Although it is possible to easily obtain a diaphragm containing 0% or more carbon fiber, it is difficult to obtain good frequency characteristics because the internal loss is small, and because carbon fiber has electrical conductivity. However, there is a drawback that the lead terminal of the voice coil cannot be attached to the diaphragm.

(Means for solving the problems) The present invention was proposed to eliminate the above-mentioned drawbacks.
Silk cloth is composed of high elastic alumina continuous fibers and high elastic fibers,
It is characterized by bonding and filling the fibers with an organic substance, an inorganic substance, or a mixture thereof, and its purpose is to provide a diaphragm with high elasticity and high loss at low cost without having electrical conductivity. There is a particular thing.

The fibers that can be used in the present invention are preferably natural fibers, synthetic fibers, composite uAH, glass fibers, polycrystalline N fibers, etc., and have a volume resistivity of 10'0-am or more. Carbon fiber has a volume resistivity of 1.1 to 2. lX1O-30-CI
Although it is small, by using alumina continuous RE, it is possible to use carbon fiber, metal fiber, beryllium mm, etc. with good electrical conductivity.

As the interfiber bonding material, organic substances such as epoxy resin, phenol resin, unsaturated polyester resin, acrylic resin, or non-m''I1 which can be cured at 150°C for 20 minutes are used.
1 binder (trade name: Kanpe CELA, manufactured by Kansai Paint Co., Ltd.) can also be used.

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

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 present invention.

(Example) The alumina continuous fiber used was Denka alumina long fiber (trade name of Denki Kagaku Kogyo Co., Ltd.), and the other high elastic fiber used in the blend was silicon carbide $1 spool (Nikalon: Nippon Carbon). Co., Ltd. (product name).

1% fiber suspension is alumina continuous fiber by weight! ,096
, 50% silicon carbide fiber.

The weave of the blend was plain weave. Figure 1 (a) shows its structure; 1 is alumina continuous fiber, 2 is a blended fiber,
In the illustrated example, the horizontal direction is alumina continuous 11alff, 11
The direction is blended 2, but you can also do it in the opposite direction, horizontally,
It goes without saying that Blend 2 may be used in both longitudinal directions. In addition, Figure 1 (b) is an enlarged view of the blended yarn.
It consists of a continuous weave of 2O, and fibers of silicon carbide (SiC). The composition of the base material (woven fabric) used is shown in Table 1.

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

Further, the physical properties of the silicon carbide tar cloth used in this are shown in Table 3.

Table 3 The sample was impregnated with Knoll resin, dried with hot air, and then heated and pressed in a mold at 250°C to form a diaphragm shape with a diameter of 20 cm.

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. This 5C-
100 is cured with an irradiation energy of 6000 mJ (millijoules), so when a high-pressure mercury lamp was used, the irradiation time was 20 seconds and it was completely cured.

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

Further, the volume resistivity at this time was 1ON2Ω-cm.

(Effects of the Invention) As described above, the present invention comprises a woven fabric made of high-modulus alumina continuous fibers and other high-modulus fibers, and an organic substance, an inorganic substance, or a mixture thereof between the fibers. By bonding and filling, it is possible to obtain a diaphragm with high elasticity, high loss, and excellent frequency characteristics without having electrical conductivity.

[Brief explanation of the drawing]

FIG. 1(A) shows the structure of the diaphragm base material of the present invention, FIG. 1(B) shows a partially enlarged view, and FIG. 2 shows the frequency characteristics. 1...Alumina continuous fiber, 2...Blended spinning Patent applicant Foster Electric Co., Ltd. (1 person) Agent Ben l
1st Master Michio Takayama (and 1 other person):”
J, 4:' ゝ-/ Figure 1 Figure 2 Zhou Zemoku (Hz)

Claims (1)

[Claims] Alumina continuous fibers, natural fibers, synthetic fibers, glass fibers having an elastic modulus of 10 x 10^3 Kgf/mm^2 or more,
A diaphragm for an electroacoustic transducer, characterized in that the fibers of a woven fabric made of single or multiple polycrystalline fibers, composite fibers, and metal fibers are bonded and filled with an organic substance, an inorganic substance, or a mixture thereof. .