JP2548998B2 - Speaker diaphragm and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a speaker diaphragm in which a plurality of materials are laminated and integrated, and the speaker diaphragm is manufactured by molding and bonding a plurality of materials. And a method for manufacturing a speaker diaphragm, which is capable of simultaneously performing the above.

(Prior Art) In the past, speaker diaphragms often consisted of cone paper made of pulp fiber, but cone paper alone is not sufficient as a speaker diaphragm that emphasizes sound quality, and is currently made of metal, plastics, ceramics, etc. Various new materials have been developed, either alone or in combination.

FIG. 4 is a partial cross-sectional view of a conventional speaker diaphragm 1, 2 is a carbon fiber reinforced resin layer obtained by curing a carbon fiber cloth with a resin, 3 is a foamed resin layer, and 4 is a pulp fiber layer. Is.

The first manufacturing method of the speaker diaphragm 1 is a carbon fiber reinforced resin layer 2, a foamed resin layer 3, and a pulp fiber layer 4.
Each of them was separately molded, for example, in the shape of a cone, and then laminated to each other with an adhesive to be integrated. Therefore, the steps of molding and bonding were required separately.

There is a second manufacturing method in which the number of steps is reduced by manufacturing this molding and bonding at the same time. For example, a manufacturing example of a speaker diaphragm in which a carbon fiber reinforced resin layer and a pulp fiber layer are laminated and laminated together. Described in. In the second manufacturing method, the cone paper 5 made of preformed pulp fibers is placed on the cone-shaped lower mold 6b as shown in the fifth,
Further, an uncured prepreg 7 in which a carbon fiber cloth is impregnated with an epoxy resin is placed on top of it, and the lower mold 6b and the upper mold are placed.
By pressing and heating with 6a, the molding of the carbon fiber reinforced resin layer and the bonding with the pulp fiber layer can be completed in one step.

(Problems to be Solved by the Invention) Although various diaphragms for speakers have been developed which are made of various new materials alone or in combination thereof, a better speaker diaphragm that emphasizes sound quality is required.

As the manufacturing method, the first manufacturing method in which different materials are separately molded into a cone shape by adhering them to the laminated body with an adhesive, and the steps of molding and adhering require man-hours, Further, it is necessary to apply the adhesive evenly at the time of adhesion and to prevent bubbles from entering between the layers, which is a problem in manufacturing.

In addition, the second manufacturing method is applicable to a speaker diaphragm having a possibility that the layers are crushed by applying pressure and heat to the laminated material, or having elasticity, for example, a foamed resin layer or a micro hollow sphere inside the layer. Can not. Therefore, as described above, the speaker diaphragm 1 of FIG. 4 is obtained by separately molding the carbon fiber reinforced resin layer 2, the foamed resin layer 3, and the pulp fiber layer 4 into a cone shape with an adhesive. There was no choice but to use the first manufacturing method, which has the problem of laminating it to the laminate.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a thermosetting resin layer containing micro hollow spheres made of a thermoplastic resin in which hydrocarbons are enclosed, and a thermosetting resin layer containing the thermosetting resin. A thermoplastic resin layer provided on both surfaces of the thermoplastic resin layer, and at least one of the thermoplastic resin layers has a high elastic fiber layer reinforced by the same thermoplastic resin as the thermoplastic resin, A diaphragm for a speaker is provided.

Further, a fine hollow sphere made of a thermoplastic resin in which hydrocarbons are enclosed is kneaded with an uncured thermosetting resin to form a uniform thickness between two sheets of the thermoplastic resin. A layer of a sheet of high elastic fiber and a sheet of the same thermoplastic resin as the above thermoplastic resin are laminated on each other to form the thickness of the finished diaphragm for a speaker. Put in a mold having a space, and after heating at a temperature and time for expanding the minute hollow spheres and curing the uncured thermosetting resin and impregnating the high elastic fiber with the thermoplastic resin, A method for manufacturing a speaker diaphragm, which is characterized by cooling.

(Embodiment) In view of the above problems, the present invention is to apply pressure and heat to, for example, a foamed resin layer or a minute hollow sphere in a material of a speaker diaphragm in which a plurality of materials are laminated and integrated. Therefore, the molding and the bonding of a plurality of materials can be performed at the same time even if the layers may be crushed or have elasticity, and the present invention will be described together with a preferred embodiment.

FIG. 1 shows a partial sectional view of an embodiment of a speaker diaphragm 8 of the present invention. In the figure, 9 is a carbon fiber reinforced resin layer, and this carbon fiber reinforced resin layer 9 is composed of carbon fiber woven cloth 9A which is a highly elastic fiber such as boron fiber and polypropylene 9B which is a thermoplastic resin. Has been done. Reference numeral 10 is an epoxy resin layer containing micro hollow spheres 11 therein, 12 is a polypropylene layer, and 13 is a pulp fiber layer.

Generally, the following four items are well known as the physical conditions required for the diaphragm of the bass speaker, which emphasizes sound quality.

The sound velocity is high.

Has a moderate internal loss.

High bending rigidity.

The weight is large.

The physical characteristics of the speaker diaphragm of the present invention are shown in Table 1 in comparison with those of the conventional pulp fiber (paper) diaphragm and the composite diaphragm of paper and high elastic fiber reinforced resin (CFRP).

However, the respective vibration plate weights were produced under the same conditions. In Table 1, loss means internal loss and rigidity means bending rigidity.

As is clear from this table, the speaker diaphragm of the present invention has an internal loss that is substantially the same as that of paper, and a sound velocity that is approximately the same as that of a composite product of paper and high elastic fiber reinforced resin (CFRP). Moreover, since the speaker diaphragm of the present invention has a small specific gravity, the bending rigidity is large because the thickness can be increased with the same weight.

Therefore, the advantage of each layer of the speaker diaphragm 8 of the present invention is that the carbon fiber layer 9 has a large sound velocity and corresponds to the above condition, and the epoxy resin layer 10 containing the minute hollow spheres 11 therein.
Corresponds to the above conditions, and the pulp fiber layer 13
Corresponds to the above conditions, and the advantages of each are combined. From this fact, the speaker diaphragm of the present invention is most suitable as a speaker diaphragm for low sound.

FIG. 6 is a characteristic diagram when the speaker diaphragm of the related art (paper CFRP) and the present invention is applied to the speaker. In FIG. 6, the broken line represents the characteristics related to the conventional diaphragm, and the solid line represents the present invention. It is a figure which shows the frequency and the 2nd harmonic distortion characteristic which concern on the diaphragm for a speaker, respectively.

As is clear from this characteristic diagram, the high-frequency resonance frequency fh is the same, but the peak level of the present invention is about 5 dB lower than the conventional one, and the second harmonic distortion is also reduced. . Further, conventionally, the frequency level due to the split resonance is disturbed at 0.5 KHz to 1.5 KHz, but that of the present invention is smooth and the second harmonic distortion is also reduced.

Next, the second method of manufacturing the speaker diaphragm of the present invention will be described.
This will be described with reference to FIGS. (A) to (D) and FIG.

2 (A) to (D) are views for explaining the method for manufacturing the speaker diaphragm of the present invention, and FIG. 3 is a cone-shaped upper part (male) used in the method for manufacturing the speaker diaphragm of the present invention. ) Mold 14
FIG. 8 is a half sectional view of A and lower (female) molds 14B. Figure 3 shows the mold
14A and 14B are shown in a combined state. In this state, a space t is maintained between the upper and lower molds 14A and 14B, and this space t is the thickness of the speaker diaphragm 8. Also, mold 14
A and 14B are respectively provided with a plurality of grooves 15A and 15B through which steam or cooling water for heating or cooling passes.

Here, in the description of the material of each step, the material that is related to the portion of the speaker diaphragm 8 that is completed in FIG.

Step, a desired diaphragm shape, here a pulp fiber cone 13a, is manufactured from the pulp fiber by a conventionally known manufacturing method ... Fig. 2 (A).

Step, uncured epoxy resin 10a uncured micro hollow spheres 11a made of acrylic resin with a hydrocarbon liquid sealed inside
Stir so that it is evenly distributed over

Step, the pulp fiber cone 13a manufactured in the step is placed on the lower mold 14B, on which the polypropylene film 12a, the micro hollow sphere 11a manufactured in the step and the uncured epoxy resin 1
0a and agitated, polypropylene film 9Ba, carbon fiber woven cloth 9Aa, polypropylene film 9Ba are laminated in this order ...
FIG. 2 (B).

In the above description, a mixture of the minute hollow spheres 11a and the uncured epoxy resin 10a is sticky, and therefore sticky. Therefore, if this is sandwiched between the polypropylene film 12a and the polypropylene film 9Ba, the workability is good.

In the process, the upper and lower molds 14A and 14B are aligned vertically, steam is sent to the grooves 15A and 15B and heated at a predetermined temperature and for a time ... Fig. 2 (C).

By this heating, the hydrocarbons in the micro hollow spheres 11a expand, and the micro hollow spheres 11a having a diameter of 20 μm initially expand about three times, that is, 20 to 30 times in volume ratio. Due to this expansion, the internal pressure inside the upper and lower molds 14A, 14B, that is, the portion at the interval t increases.

Due to this increase in internal pressure and heating, the polypropylene film 9Ba, which is a thermoplastic resin, is softened and impregnated in the carbon fibers 9Aa, and the layers are bonded together. Of course, the uncured epoxy resin 10a is also cured by heating.

Therefore, the heating temperature and time here should be such that the minute hollow spheres 11a do not expand too much and are destroyed, and the epoxy resin 1
It is set to satisfy three conditions: 0a is hardened and polypropylene film 9Ba is melted.

Details of the heating temperature and time are shown in FIG. 2 (D). As is clear from FIG. 2 (D), the temperature is raised to about 160 ° C. in about 90 seconds and kept at this temperature. At this time, the epoxy resin 10a begins to cure.

After maintaining the temperature for about 60 seconds, the temperature is set to about 180 ° C. to soften the polypropylene film 9Ba to sufficiently impregnate the carbon fibers 9Aa, cure the epoxy resin 10a, and expand the micro hollow spheres 11a.

Step, as shown in FIG. 2 (D), 180 seconds after the start of heating, cooling water is sent to the pipes 15A and 15B so that the minute hollow spheres 11a do not expand too much and are destroyed. It cools rapidly, the diaphragm 8 for speakers is taken out, and it is completed.

Through the above steps, the carbon fiber reinforced resin layer 9, the epoxy resin layer 10 and the polypropylene layer 12 were produced and molded, and the pulp fiber layer 13 and the like were bonded at the same time.

(Effect of the invention) As described above, according to the present invention, in a material of a speaker diaphragm in which a plurality of materials are laminated and integrated, a pressure such as a foamed resin layer or a layer including micro hollow spheres is applied. , Even if the layer is likely to be crushed by heating, or even if it has elasticity, molding and bonding of multiple materials can be performed at the same time, the process can be shortened, and a speaker diaphragm suitable for a bass speaker can be obtained. There are features.

[Brief description of drawings]

FIG. 1 is a partial sectional view of an embodiment of a speaker diaphragm 8 of the present invention, and FIGS. 2A to 2D are views for explaining a method of manufacturing the speaker diaphragm of the present invention. FIG. 3 is a half sectional view of a mold used in the method for manufacturing a speaker diaphragm of the present invention,
FIG. 4 is a partial sectional view of a conventional speaker diaphragm 1;
FIG. 6 is a diagram for explaining a conventional manufacturing method, and FIG. 6 is a characteristic diagram of a speaker. 8 ... Vibration plate for speaker of the present invention, 9 ... Carbon fiber woven fabric (high elastic fiber) reinforced thermoplastic resin layer, 9A ... Carbon fiber (high elastic fiber), 9B ... Polypropylene, 10 ... Epoxy resin Layer, 11 ... Micro hollow sphere, 12 ... Polypropylene layer, 13 ... Pulp fiber layer, 14A ... Top (male) mold, 14B ... Bottom (female) mold, 15A, 15B ... Heating and cooling Groove for

Claims (2)

(57) [Claims] In a speaker diaphragm, a thermosetting resin layer containing minute hollow spheres made of a thermoplastic resin in which hydrocarbons are enclosed, and a thermosetting resin layer provided on both surfaces of the thermosetting resin layer. A speaker diaphragm, comprising: a thermoplastic resin layer; and a high-elasticity fiber layer reinforced by the same thermoplastic resin as the thermoplastic resin on at least one of the thermoplastic resin layers. 2. A method in which minute hollow spheres made of a thermoplastic resin in which a hydrocarbon is encapsulated are kneaded with an uncured thermosetting resin to form a uniform mixture between two sheets of the thermoplastic resin. A finished speaker diaphragm, which is made into a layer with a thickness and on which a sheet-shaped material of high elastic fiber and a sheet-shaped material made of the same thermoplastic resin as the thermoplastic resin are laminated respectively. In a mold having a space of the thickness of, the expansion of the minute hollow spheres and the curing of the uncured thermosetting resin, and heating at a temperature and time for which the high elastic fiber can be impregnated with the thermoplastic resin. A method of manufacturing a speaker diaphragm, comprising: