JPH0583793A - Acoustic diaphragm and its manufacture - Google Patents

Abstract

PURPOSE:To perform the solid formation of the curved-face shape, etc., while the characteristics of the wood which are a natural raw material is made active, to apply to the conventional forming technology and to relax the dispersion of the physical properties without increasing the production cost by forming the woven fabric unioned by the weft and the warp composed of the slit product to the curved-face shape. CONSTITUTION:Wood 1 is sliced to a sheet 2 with the prescribed thickness, next, the drug processing is performed, and thus, the sheet 2 is softened. Both ends of the sheet 2 are fixed by the paper tape, etc., slitted fine to the thread shape by a cutting machine and made into a slit product 3. Two slit products 3 are used, respective are made into the warp and the weft, and unioned by a weaving machine. After the thermosetting resin is impregnated to a unioned woven fabric 4, the resin is set into the prescribed die, and the woven fabric set to the die is heated, pressurized and formed by the prescribed temperature. Thus, an acoustic diaphragm 6 with high rate elastic modulus (E/eta) and excellent acoustic characteristics is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acoustic diaphragm which oscillates in response to an acoustic signal and emits an acoustic sound into a space, and a method of manufacturing the same.

[0002]

2. Description of the Related Art (1) Some conventional acoustic diaphragms are made of a mixed woven fabric using two or more kinds of highly elastic synthetic fibers or inorganic fibers. (2) Further, in the conventional acoustic diaphragm, there is also a flat diaphragm based on wood which is a natural material. This flat plate type diaphragm is manufactured, for example, by the following manufacturing method. First, wood is sliced, and the hydroxyl groups of the sliced wood are replaced with acetic acid groups by acetic anhydride to eliminate the water absorption of the wood, thereby increasing the dimensional stability of the wood. Then, the wood that has been subjected to such a treatment is used as a plywood, and is formed into a flat diaphragm.

[0003]

In order for the above-mentioned acoustic diaphragm to have excellent acoustic characteristics, it must be lightweight, have high rigidity, that is, have a high specific elastic modulus (E / ρ) and a large internal loss. is necessary. By the way, since the conventional acoustic diaphragm of (1) described above has a higher density ρ than wood, the specific elastic modulus (E / ρ) is lower than that of the acoustic diaphragm using wood.
Therefore, there is a drawback that it is difficult to increase the film thickness to increase the rigidity, and good acoustic characteristics cannot be obtained. In addition, when a highly elastic carbon fiber is used, a relatively high specific elastic modulus (E /
However, since the internal loss is too small, the characteristic resonance peak is sharp in the high range, and good acoustic characteristics cannot be obtained.

On the other hand, the conventional acoustic diaphragm of the above (2) has a characteristic that the specific elastic modulus (E / ρ) is high and the acoustic characteristics are excellent, but the shape is limited to a planar shape. Therefore, there is a drawback in that it is difficult to form a curved shape like a cone-type acoustic diaphragm of a conventional speaker in three dimensions. Therefore, the conventional processing technology cannot be applied, and as a result, the cost at the time of production becomes high.

Further, since the conventional acoustic diaphragm of the above (2) uses wood which is a natural material, it has drawbacks in that various physical properties are varied and anisotropic. The present invention has been made under such a background, and it is possible to perform three-dimensional molding such as curved surface shape while utilizing the characteristics of wood, which is a natural material, and to disperse various physical properties of the natural material. It is an object of the present invention to provide an acoustic diaphragm and a method for manufacturing the same that can alleviate the noise and can be manufactured at low cost.

[0006]

According to a first aspect of the present invention, there is provided an acoustic diaphragm in which a woven fabric which is woven by weft threads and warp threads made of sliced wood is formed into a curved shape. I am trying. Further, in the method for manufacturing an acoustic diaphragm according to the invention of claim 2, after slicing wood into a sheet, the sheet is softened, and the sheet subjected to the softening treatment is thinly slit into a thread shape to form a slit product, The slit product is woven as a weft yarn and a warp yarn, and the woven fabric is impregnated with a thermosetting resin, and then heated and pressed to form a diaphragm for acoustic production.

[0007]

According to the structure of the acoustic diaphragm of the present invention, the specific elastic modulus (E / ρ) is high and the acoustic characteristics are excellent. Further, according to the method of manufacturing an acoustic diaphragm according to the second aspect of the present invention, the acoustic diaphragm based on wood, which is a natural material, can be formed into a curved shape.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a process diagram showing a method of manufacturing an acoustic diaphragm according to an embodiment of the present invention. Hereinafter, the manufacturing process will be described step by step. Process Wood 1 is sliced into a sheet 2 of about 20 to 80 μm (see FIG. 1A). For the brand of wood 1, Sitka spruce wood is the most suitable from the physical property value,
Cedar and beech wood can be used. Next, the sheet 2 is softened by chemical treatment. As the chemical treatment, after immersing the sheet 2 for about 10 to 15 minutes in a softening agent (treatment liquid in which a natural product is blended based on an aqueous urethane emulsion) heated to a temperature of 20 to 80 ° C.,
The softening agent is polymerized by heating at a temperature of about 50 ° C. for several minutes.

Steps Both ends of the sheet 2 are fixed with paper tape or the like, and slitted into a thread shape of about 0.6 to 1.0 mm by a cutting machine to make a slit product 3 (FIG. 1B).
See). The width W of the slit product 3 of this embodiment is 12
The length L is 0 mm and the length L is 900 mm or less. Process As shown in FIG. 1C, two slit products 3 described above are used as warp yarns and weft yarns, respectively, and are woven by a loom.

Step: After the woven fabric 4 is impregnated with the thermosetting resin 5, it is set in a predetermined mold. Then, the woven fabric set in the mold is heated and pressed at a temperature of about 100 ° C. to be molded. As a result, FIG. 1 (d)
The cone-type acoustic diaphragm 6 shown in is completed. Note that FIG.
FIG. 3 is an enlarged view of a part 6a of the acoustic diaphragm 6 shown in FIG. 1 (d).

As described above, the acoustic diaphragm 6 according to the embodiment of the present invention is different from the conventional acoustic diaphragm in that
The elastic modulus E is high, and the specific gravity ρ of the acoustic diaphragm 6 is low. Therefore, the specific elastic modulus (E / ρ) and sound velocity (E /
ρ) ^1/2 and (E / ρ ³ ) are higher than the conventional acoustic diaphragm. Also, the bending rigidity E · I is large, and the moldability is good. This is because the moment of inertia I is proportional to the cube of the thickness,
This is because if the specific mass is the same, the smaller the specific gravity ρ, the thicker the film can be and the larger the bending rigidity E · I becomes. Therefore, it is advantageous as compared with the conventional acoustic diaphragm. As described above, the acoustic diaphragm 6 according to the embodiment of the present invention has excellent acoustic characteristics and improved sound quality as compared with the conventional acoustic diaphragm. The physical properties of the acoustic diaphragm 6 according to the embodiment of the present invention are further improved by selecting the material such as the wood 1 and optimizing each condition.

In the above-described embodiment, the seat 2
The thickness is about 20 to 80 μm for the following reason. First, if the sheet 2 is too thick, it is generally difficult to form a curved surface at the time of molding, and at the time of chemical treatment,
This is because the softening agent does not penetrate sufficiently. So 80
The condition of not more than μm is the permissible range of the current impregnation conditions in the process. On the other hand, if the thickness of the sheet 2 is too thin, the mechanical strength of the slit product 3 itself decreases, and cracks are likely to occur during processing. The condition of 20 μm or more is the limit value of the current slicer.

Further, in the process of one embodiment described above, the slit product 3 has a width W of 120 mm and a length L of 900.
Although the example in which it is less than or equal to mm is shown, the invention is not limited to this. In short, as long as it is possible to cover the area of the cone type acoustic diaphragm 6 to be molded, basically any size may be used, and several sheets may be sprinkled in the width direction.

[0014]

As described above, according to the present invention,
Light weight, high rigidity and specific elastic modulus (E / E) of natural wood
There is an effect that three-dimensional molding such as a curved surface shape of a cone-type acoustic diaphragm can be performed while utilizing the characteristics that ρ) is high and the acoustic characteristics are excellent.

Further, since the conventional molding technique can be applied,
The effect is that the cost during production does not increase. Furthermore, there is an effect that it can be alleviated by interweaving the variation of physical properties, which is a drawback of natural materials. In addition, since it is possible to give the acoustic diaphragm a grain effect, the visual effect is great.

[Brief description of drawings]

FIG. 1 is a process drawing showing a method for manufacturing an acoustic diaphragm according to an embodiment of the present invention.

FIG. 2 is a part 5a of the acoustic diaphragm 5 shown in FIG.
FIG.

[Explanation of symbols]

1 ... Wood, 2 ... Sheet, 3 ... Slit product, 3a ...
… Filamentous wood, 4 …… woven fabric, 5 …… thermosetting resin, 6 ……
Acoustic diaphragm.

Claims (2)

[Claims] 1. A diaphragm for acoustic use, wherein a woven fabric which is woven by slicing and slitting a weft yarn and a warp yarn made of wood is formed into a curved shape. 2. A sliced piece of wood is made into a sheet, which is then softened, and the softened sheet is slit into a thread shape to form a slit product, and the slit product is woven as a weft thread and a warp thread and woven. A method for manufacturing an acoustic diaphragm, comprising: impregnating a woven fabric with a thermosetting resin, and then heating and pressing to form the acoustic diaphragm.