JPH0453395A - Cabinet for speaker - Google Patents

Abstract

PURPOSE:To obtain a speaker cabinet in which high stiffness and a large internal loss are made compatible by using a composite of inorganic high elastic fibers and thermoplastic synthetic resin fibers. CONSTITUTION:Inorganic high elastic high fibers are bound and made composite with molten thermoplastic synthetic resin fibers at heat forming. As the liquid crystal high polymer fibers, carbon fibers employed. Since the two kinds of materials forming a composite member are formed while being close to each other or in mixture in the state of fibers, the heat conduction of the raw material is excellent and the distribution of the thermoplastic synthetic resin fibers is made uniform. Then high stiffness is attained and a factor tandelta representing internal loss is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cabinet used in a speaker device.

[Prior Art] As is well known, speaker cabinets hold a speaker during use, acoustically isolate the space in front of and behind the speaker diaphragm, and prevent the effects of anti-phase sound waves emitted from the back of the diaphragm. It has the effect of increasing the acoustic radiation efficiency by preventing sound radiation, and improving the frequency characteristics of the speaker device by installing an acoustic circuit such as a duct.Speaker cabinets with this effect reduce the internal sound pressure and the speaker drive system. The material that makes up the cabinet should be as rigid as possible in order to prevent the negative effects of the cabinet's self-vibration. In addition, a large vibration absorption force is required to suppress abnormal resonance of the diaphragm.

The typical structure of conventional cabinets is, for example (
1) Items made of a single material such as wood, metal, or synthetic resin;
(2) A mixture of fillers such as wood or carbon fiber with a thermosetting resin and heat molding, and (3) A mixture of the above filler and a thermoplastic synthetic resin and heat molding have been put into practical use. There is.

[Problems to be solved] Conventional cabinets having such a structure have the above (1)
It is difficult for cabinets made of a single material belonging to category (2) to have both rigidity and vibration absorbing power due to the properties of the material, and for cabinets made of a combination of filler and binding material belonging to category (2), the binding material is thermoset. Since it is a plastic, it has low impact resistance, water resistance, and long-term stability. Furthermore, products whose molding cycle during production is long and whose molding raw material is in the form of prepreg do not have good storage stability. Furthermore, when a cabinet belonging to category (3) is made of, for example, polypropylene resin as the thermoplastic synthetic resin, the drape during molding is poor and high-pressure pressing is required, which is a problem to be solved.

Therefore, the present invention solves the problems of the above-mentioned conventional examples by using a composite of inorganic high modulus fibers and thermoplastic synthetic resin fibers, and achieves both high rigidity and large internal loss in a speaker cabinet. The purpose is to provide

[Means for Solving the Problems] A speaker cabinet according to the present invention for achieving the above object is made of inorganic high elastic fibers and thermoplastic synthetic resin fibers, and the inorganic high elastic fibers are heat molded. This speaker cabinet is characterized in that it is bonded and composited with thermoplastic synthetic resin fibers that are sometimes molten.

[Function] Like the cabinet with the above structure, inorganic high elastic fibers
When composited by fusion bonding with thermoplastic synthetic resin fibers, the two materials are fibrous compared to a material that is a mixture of a bulk thermoplastic synthetic resin and an inorganic high elastic filler, Furthermore, by using a thermoplastic synthetic resin with large internal loss and low density at room temperature, the apparent density of the composite material can be lowered ((Young's modulus)
/(density)) and (tan δ) representing internal loss can both be increased.

Conventionally, in order to combine inorganic high modulus fibers and thermoplastic synthetic resin, a composite sheet is created by thermo-compression bonding thermoplastic synthetic resin sheets from both sides of an inorganic high modulus fiber woven sheet, and the composite sheet is shaped into a predetermined shape. Previously, press molding was used, but in this composite sheet state, the thermoplastic synthetic resin sheet itself has poor elongation, and heat transfer during pressing is poor, so when molded into a box-like deep shape like a cabinet The drawability was not good, so it was necessary to increase the press pressure, and the distribution of the thermoplastic synthetic resin after molding could only be uneven.In contrast, the method of the present invention allows two types of composite materials to be formed. Since the materials are molded in the form of fibers in close proximity to each other or in a mixed state, the heat conduction of the materials is good and the distribution of the thermoplastic synthetic resin is uniform.

Furthermore, since one of the fibers is a thermoplastic synthetic resin fiber, it has excellent impact resistance and storage stability, and the molding time can be shortened.

Furthermore, compared to conventional thermoplastic synthetic resin composites, it has superior drapability and wettability, resulting in no voids and stable quality.

[Example] A plain woven fabric of carbon fiber was used as the inorganic high elasticity fiber, a plain woven fabric of PEEK (polyether ether ketone resin...melting point 334°C) fiber was used as the thermoplastic synthetic resin fiber, and a plain woven fabric of carbon fiber was used as the inorganic high elasticity fiber. Plain woven fabric made of PP fibers are alternately layered on both sides of the plain woven fabric to make 10 layers, press-formed at a maximum temperature of 380°C for 120 minutes to create a flat composite material, and this composite material is cut and bonded. I got a cabinet for the speaker.

The molding conditions of the composite material affect the crystal growth of the matrix resin, and greatly affect the elastic modulus, rigidity, and shape accuracy of the molded product, but in the above example, the press pressure was 10 kg.
The temperature is gradually raised at 320° C. for 10 minutes, and the press pressure is varied between 0 and 30 Kg/crl to degas the air in the fibers. Next, increase the press pressure to 30Kg/cIIr.
The temperature was raised to 380°C for 20 minutes, and then cooled to 120°C over 40 minutes.

Table 1 shows the tensile strength and flexural modulus of the cabinet at room temperature, and Table 2 shows the values of tan δ and density ρ. For comparison, the above physical property values of a conventional cabinet obtained by laminating carbon fiber woven epoxy resin prepreg are also shown. These results show that the composite cabinet of the present invention has high elasticity and a large tan δ compared to the conventional example.
It shows.

Table 1: Tensile strength: Unit: kg/mm2 Flexural modulus: Unit: kg/WII2 Table 2: E: Young's modulus: Unit: d y n
e/alρ; density 〃・・・・・・gT/Cl1
13 As a means for obtaining the composite of the present invention, as a modification 1 of the above embodiment, a woven fabric (cross weave, 3 It can also be obtained by stacking and molding multiple layers of shank weave, disk weave, etc. Further, as a second modification, a plurality of layers of a braided matrix fabric in which the surface of inorganic high elasticity fibers is wrapped with thermoplastic synthetic resin fibers may be stacked and molded.

Alternatively, as a third modification, it is possible to use a woven fabric made by interweaving two types of fibers.

In addition to the carbon fibers used in the examples, glass fibers can be used as the inorganic high-elastic fibers constituting the composite material of the present application, and a wide range of thermoplastic synthetic resin fibers such as polyethylene, nylon, polypropylene ethylene copolymer, polyamideimide, etc. can be used. General-purpose plastics and engineering plastics can be used at any time.

Above, the speaker cabinet according to the present invention has been described in detail based on embodiments that are considered to be representative, but the embodiments of the cabinet according to the present invention are limited to the structure of the above embodiments in terms of the material of the resin material, etc. The present invention is not limited to the above, but may be implemented with appropriate modifications as long as it has the constituent elements described in the claims, exhibits the functions of the present invention, and has the effects described below.

[Effects] The speaker cabinet according to the present invention has high rigidity and a low apparent density because inorganic high elastic fibers are melt-bonded and composited with thermoplastic synthetic resin fibers. Therefore, both the value of the bending elastic modulus and tan δ representing internal loss can be increased.

Furthermore, since thermoplastic synthetic resin fibers are used, it has excellent impact resistance, water resistance, long-term stability, and storage stability.

Furthermore, since the two types of materials forming the composite material are molded in the form of fibers in close proximity to each other, the materials have good heat conduction and productivity, and the molding time can be shortened. Furthermore, since the fibers are semi-mixed, the distribution of the thermoplastic synthetic resin is uniform, and compared to conventional sheet-like thermoplastic synthetic resin composites, it has excellent drape and wettability, eliminating voids. This has the effect of stabilizing quality without any problems.

Patent applicant: Onkyo Corporation

Claims (2)

[Claims] (1) A speaker characterized in that it is made of a material made of inorganic high elastic fibers and thermoplastic synthetic resin fibers, and the inorganic high elastic fibers are bonded and composited by thermoplastic synthetic resin fibers that are melted during heat molding. cabinet for (2) The speaker cabinet according to claim 1, wherein the inorganic high modulus fiber is carbon fiber.