JPS61191196A - Speaker box - Google Patents

Abstract

PURPOSE:To improve the formability and the productivity and an appearance by constituting a speaker box with the composite material of thermoplastic resin containing fine spherical hollow bodies or containing fine spherical hollow bodies and inorganic filler. CONSTITUTION:A speaker 2 is attached at the inside of the speaker box 1 facing outside, and a through hole 3 is provided corresponding to the speaker 2. The speaker box 1 is made of the composite material of thermoplastic resin containing 5-40% of the fine spherical hollow bodies or the fine spherical hollow bodies and the inorganic filler. By such a manner, sound energy is resisted by the wall of spheres or the zone of air to become sound absorbing effect, and large internal loss is obtained. As the fluidity of the thermoplastic resin composite material containing fine spherical hollow bodies is high, the formability and the productivity can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a speaker box used in audio equipment.

[Technical background of the invention and its problems] Materials used for speaker boxes generally have characteristics such as high density and high rigidity, high internal loss against vibrations, and rapid damping of vibrations. It is desirable to do so.

However, wood, plywood, particle board, etc. are mainly used as conventional speaker box materials. These materials generally have low density and insufficient internal loss. In addition, since the raw material is a natural material, it is easily subject to material variations and deformation over time due to humidity. Further assemble,
There are many processing steps such as painting, which reduces productivity.

On the other hand, in recent years, thermoplastic resin composites containing powder or ilft inorganic fillers have been developed as materials that have high density and rigidity, can be injection molded, extrusion molded, compression molded, etc., and have high productivity. is used.

However, it contains large amounts of inorganic fillers to maintain density and stiffness, reducing internal losses and material flowability.

Further, foamed resin is a material characterized by a large internal loss, but this material reduces density and rigidity, and furthermore, the surface of the molded product becomes porous during processing and molding, which significantly impairs the appearance.

[Object of the Invention] The present invention was made in view of the above-mentioned circumstances, and an object of the present invention is to provide a speaker box having excellent acoustic properties, good moldability, ease of production, and good appearance.

[Summary of the Invention] The speaker box of the present invention is composed of a thermoplastic resin composite material containing a microspherical hollow body or a microspherical hollow body and an inorganic filler.

[Embodiments of the invention] Embodiments of the present invention will be described in detail below with reference to the drawings.

The drawing shows an example of a speaker device, with speaker box 1
A speaker 2 is mounted inside thereof facing outward, and a through hole 3 is provided in the speaker box 1 corresponding to the speaker 2.

The speaker box 1 contains a microsphere-hollow body or a microspherical hollow body and an inorganic filler at a content rate of 5 to 40 (vol.
%) composed of thermoplastic resin composite material. As the microspherical hollow body, a spherical hollow body having a diameter of 200 μm or less and made of a silicon compound, carbon, metal, or thermosetting resin is used.

Further, as the inorganic filler, powders or fibers of metals, metal oxides, silicon compounds, mica, natural clay, etc. are used.

One of the characteristics required for the speaker box material is that it has a large internal loss (tan δ).

In this respect, the thermoplastic resin composite material containing microspherical hollow bodies as in the present invention causes sound waves to vibrate the floor wall, thereby attenuating the sound energy. In addition, sound energy is resisted by the floor walls and air zones, resulting in a sound absorption effect and a large internal loss. Although foamed resin has a similar effect, unlike foamed resin, the surface of the molded product is not porous, so secondary processing such as painting is not required.

It is also necessary to have high rigidity as a characteristic, and sufficient rigidity can be obtained by incorporating microspherical hollow bodies or a composite of microspherical hollow bodies and inorganic fillers.

Furthermore, thermoplastic resin composites containing inorganic fillers have reduced fluidity, but thermoplastic resin composites containing microspherical hollow bodies have good fluidity, leading to improved moldability and productivity.

[Specific Example of the Invention 1] Polypropylene having a density of 0.91 g/α3 and a melt index of 13.0 was mixed with alumina spherical hollow bodies with an average particle size of 100 μm and an inorganic filler in the composition ratio (volume ratio) as shown in Table 1. Mica powder with a particle size of 75 μm was tumbled (50
The mixture was stirred and mixed using rpnn for 5 minutes.

Next, this mixture was molded using injection molding II (Toshiba Machine IS-45P).
A test piece measuring 10 s x 100 x 3 m was prepared by injection molding using an N type. Holding one end of the test piece thus prepared, the internal loss (tan δ) and Young's modulus at the resonant frequency were measured using an excitation tester, and the strength and melt index were measured using a Dynstat impact tester. are shown in Table-1.

[Specific example 2 of the invention] Density 0.91 g/α3, melt flow index 13
．． Composition ratio (volume ratio) as shown in Table 1 to polypropylene of
Then, fine calcium carbonate powder having an average particle size of 0.5 μm was kneaded using a pressure kneader (30 rpII). After pulverizing this into pellets, it was stirred and mixed with silica spherical hollow bodies having an average particle size of 75 μm in a tumbler (50 rpm) for 5 minutes.

Samples of this mixture were made by injection molding in the same manner as in Example 1, and measurements were conducted under the same conditions. Table 1 shows the results.
Shown below.

6-1 [Effects of the Invention] As described above, according to the present invention, it is possible to provide a speaker box having excellent acoustic properties, good moldability, productivity, and appearance.

[Brief explanation of drawings]

The figure is a sectional view showing one embodiment of the present invention. 1...Speaker box, 2...Speaker, 3...
・Through hole.

Claims (5)

[Claims] (1) A speaker box characterized by being constructed from a thermoplastic resin composite material containing microspherical hollow bodies or microspherical hollow bodies and an inorganic filler. (2) The speaker box according to claim 1, wherein the content of the microspherical hollow bodies or the microspherical hollow bodies and the inorganic filler is 5 to 40 [vol%]. (3) The speaker box according to claim 1, wherein the microspherical hollow bodies are made of a silicon compound, carbon, metal, or thermosetting resin. (4) The speaker box according to claim 1, wherein the microspherical hollow bodies are microspherical hollow bodies having a diameter of 200 μm or less. (5) The speaker box according to claim 1, wherein the inorganic filler is made of metal, metal oxide, silicon compound, mica, natural clay powder or fiber.