JP2961202B2 - Dust cap for speaker - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a dust cap for a cone type speaker.

[Related Art] As is well known, a dust cap of a cone type speaker is located near the center of a diaphragm and has a function of blocking foreign matter such as dust. Since it affects the vibration mode of the diaphragm,
It is required that the rigidity is large to some extent and the vibration absorption force for suppressing abnormal resonance of the diaphragm is relatively large.

A typical structure of a conventional dust cap is, for example, (1) a single material such as pulp, metal, synthetic resin, or the like, or (2) a carbon fiber woven fabric or the like impregnated with a thermosetting resin and heat molded. (3) Laminating a carbon fiber woven fabric or the like and a thermoplastic synthetic resin sheet, and heat-forming the same, and the like have been put to practical use.

[Problem to be Solved] A conventional dust cap having such a structure is as follows.
It is difficult for the dust cap belonging to (1) to achieve both rigidity and vibration absorption due to the nature of the material, and the dust cap belonging to (2) has impact resistance because the binder of the fibers is a thermosetting resin. Low water resistance and low long-term stability.
Further, the molding cycle at the time of production is long, and the preservability of the prepreg as a molding material is not good. Further, the dust cap belonging to (3) has a problem to be solved in that, for example, when polypropylene resin is used as the thermoplastic synthetic resin sheet, the drape at the time of molding is poor, and a high-pressure press is required.

Therefore, the present invention solves the problems of the above-described conventional example by using a liquid crystal polymer fiber and a thermoplastic synthetic resin fiber in combination, and achieves a speaker with both high rigidity and a large internal loss. It is intended to provide a dust cap.

[Means for Solving the Problems] In order to achieve the above object, a dust cap of a speaker according to the present invention includes a liquid crystal polymer fiber and a thermoplastic synthetic resin fiber, and the liquid crystal polymer fiber is A speaker dust cap characterized in that the dust cap is combined and compounded by thermoplastic synthetic resin fibers melted during heat molding.

[Operation] The liquid crystalline polymer fiber has a lower density (ρ), a higher cutting strength (1.5 to 2 times that of carbon fiber, etc.) and a lower melting point than a conventional composite material such as carbon fiber. Since it is a high temperature of 300 ° C. or higher, it is thermally stable. Further, since the fiber has a fibril structure, the internal loss (tan δ) of the fiber itself is large.

By compounding liquid crystalline polymer fibers with such properties with molten thermoplastic synthetic resin fibers, the liquid crystalline polymer fibers are uniformly dispersed in the composite material and the physical properties of the composite material are Ρ is smaller and tan δ is larger than a composite material using carbon fiber or the like. Furthermore, since both fibers are thermoplastic synthetic resin fibers, they are excellent in impact resistance and storage stability, and the molding time can be shortened because the two types of fibers are in close contact. In addition, since it is excellent in drapability and wettability as compared with the conventional sheet-like thermoplastic synthetic resin composite, the quality is stable without voids.

[Example] Plain woven fabric of wholly aromatic polyester fiber as liquid crystalline polymer fiber, and plain woven fabric of PP (polypropylene resin: glass transition temperature = 0 ° C, melting point 170 ° C) fiber as thermoplastic synthetic resin fiber. Using a plain woven cloth of PP fibers on both sides of a plain woven cloth of wholly aromatic polyester fibers to make three layers, press molding with a dome-shaped mold at 140 ° C for 2 minutes to obtain a dust cap for speakers .

Table 1 shows the values of tan δ, Young's modulus E, density ρ, and E / ρ of the dust cap at room temperature, and Table 2 shows the molding conditions. For comparison, the above physical properties of a conventional dust cap obtained by laminating a carbon fiber woven fabric and a polypropylene sheet are also shown. From these results, the composite dust cap of the present invention has higher rigidity and larger
nδ is shown. Especially for molding pressure,
As compared with the case of a composite made of a sheet, the misregistration of fibers can be used, so that it is easy to give a shape, and since it is a fiber, it is easy to melt.

As means for obtaining the composite of the present invention, as a first modification of the above-described embodiment, a woven fabric (combing weaving) made of long fiber (commingled yarn) mixed with a liquid crystalline polymer fiber and a thermoplastic synthetic resin fiber is used. (Triaxial weave, disc weave, etc.) in one or more layers. Further, as a second modification, a single layer or a plurality of layers of a woven fabric of a pride matrix in which the surface of a liquid crystalline polymer fiber is wrapped with a thermoplastic synthetic resin fiber may be formed. Alternatively, as a third modification, means using a woven fabric in which two kinds of fibers are mixed and woven is conceivable.

As described above, the dust cap of the speaker according to the present invention has been described in detail based on the example which is considered to be representative. However, the embodiment of the dust cap according to the present invention is based on the structure of the above example in the material of the material resin and the like. It is not limited to
The present invention can be appropriately modified and implemented as long as it has the components described in the above-mentioned claims, exhibits the function of the present invention, and has the effects described below.

[Effect] In the dust cap of the speaker according to the present invention, the liquid crystalline polymer fiber is melt-bonded with thermoplastic synthetic resin fiber to form a composite, and the liquid crystalline polymer fiber is formed of a conventional composite material such as carbon fiber. 1.5 to 2 of density fiber etc.
In addition, the fiber has a high melting point as high as 300 ° C. or higher, and is thermally stable. Further, since the fiber has a fibril structure, the internal loss (tan δ) of the fiber itself is large.

By combining liquid crystalline polymer fibers of such properties with molten thermoplastic synthetic resin fibers, the liquid crystalline polymer fibers are uniformly dispersed in the composite material, and the physical properties of the composite material are the same as those of conventional carbon fibers. Ρ is small and tan δ is large as compared with a composite material using the same.

In addition, since the thermoplastic synthetic resin fiber is used, it is excellent in impact resistance, water resistance, long-term stability and storage stability, and since two kinds of fibers are in a half-mixed state,
The molding time can be shortened. In addition, since it is excellent in drapability and wettability as compared with a conventional sheet-like thermoplastic synthetic resin composite, it has the effect of eliminating voids and stabilizing the quality.

Claims (2)

(57) [Claims] 1. A liquid crystal polymer fiber and a thermoplastic synthetic resin fiber, wherein the liquid crystal polymer fiber is bonded and compounded by a thermoplastic synthetic resin fiber melted during heat molding. A woven fabric made of long fibers obtained by mixing the liquid crystal polymer fiber and the thermoplastic synthetic resin fiber, a pride matrix woven fabric in which the surface of the liquid crystal polymer fiber is wrapped with the thermoplastic synthetic resin fiber, or A dust cap for a speaker, which is formed by heating and forming a woven fabric in which liquid crystalline polymer fibers and the thermoplastic synthetic resin fibers are woven together. 2. A dust cap for a speaker according to claim 1, wherein said liquid crystalline polymer fiber is a copolyester of ethylene or a copolyester of phenylene or biphenylene comprising parahydroxybenzoic acid and terephthalic acid. .