JPS6135096A - Diaphragm for speaker - Google Patents

Abstract

PURPOSE:To obtain the hardness and water proof the same or more as a thermosetting resin by making natural and chemical fibers or their mixture, impregnating a cellulose nitrate solution and constituting a diaphragm from a dried and cured base material. CONSTITUTION:A fiber 1 is filled by a cellulose nitrate 2. Accordingly the strong bondage between the fibers 1 and the filling by a solution of the cellulose nitrate 2 improve a water proofing effect. The fiber 1 means a natural or chemical fiber, and the base material 4 is formed by making the natural or chemical fiber alone or their mixture.

Description

[Detailed description of the invention] Technical field The present invention is applied to a speaker diaphragm.

The performance required for 1ii*) J boards for speakers is that they are lightweight, have a good PiAt rate, and have a low density variation, so that the output sound pressure frequency characteristics of the speaker can be improved. This means that it has a large internal loss. In other words,
17 The higher the rate and the lower the density, the higher the resonant frequency of the diaphragm, and the wider the piston movement area, the wider the frequency band of the speaker, and the larger the internal loss, the less divided resonance of the diaphragm, and the higher the frequency. The characteristics are flattened.

For this reason, conventionally beaten natural fiber eaves 1, chemical M
Vibration plates formed by paper-making of fibers of group Ii or a mixture thereof are widely manufactured. Since such diaphragms are manufactured by paper-making, they are susceptible to water and humidity.
Swelling due to moisture absorption and deterioration of performance occur.

However, recently, speakers are being used outdoors and in cars.
As seen in the case of door mounts, the usage of speakers has expanded, and more and more speakers are exposed to water and moisture. Therefore, the diaphragm itself of the speaker is required to have water repellency and water resistance.

Conventional methods for increasing the water resistance of diaphragms include, for example, attaching a thermosetting resin to the base material after papermaking and applying heat and pressure treatment to cover the main surface of the diaphragm, and
A known method is to mix and form an Iwi resin with a natural fiber, a chemical fiber, or a fiber N material that is a composite of these, and then perform a process such as heating and pressurization to adhere the resin to the main surface. ing.

However, although the diaphragm A3, which has been waterproofed using the conventional method described above, has high waterproofness and a large Young's modulus, it is difficult to flatten the sound pressure frequency characteristics because the density is too large and the internal loss is small. It is. In addition, when using the latter method, if the heated Wi-resin fiber is added until it has sufficient waterproofness, the Young's modulus decreases, and the output level in the high range of the sound pressure frequency characteristic decreases, and the efficiency increases. It always got worse.

As described above, conventional speaker diaphragms have not been able to simultaneously satisfy sufficient waterproof properties and desirable physical properties such as Young's modulus, density, and internal loss.

SUMMARY OF THE INVENTION An object of the present invention is to provide a diaphragm for a speaker that has a high Young's modulus, low density, sufficient internal loss, and sufficient water resistance.

The speaker diaphragm of the present invention is characterized by comprising a base material made of natural fiber, chemical fiber, or a mixture thereof, impregnated with a solution of L-D cellulose, and dried and hardened. There is C.

EXAMPLE Hereinafter, an example of the present invention will be described based on the accompanying drawings and the table below.

First, a natural fiber such as NBKP (softwood bleached kraft valve) as a raw material is beaten to a degree of beating of 20 to 22 degrees SR. Thereafter, the paper is made by dispersing it in the suspension in a papermaking tank, using a papermaking screen with a desired diaphragm shape, for example, a cone shape, and then into a cone shape mold with a 180° 0 culm degree. Then, the base 8 is formed by drying under a press at a pressure of about Ω/Cm' at 3°0.

Next, a solution of -1-1 hillulose is prepared by blending the composition as shown in Table 1.

21. -1-1, -/ 7゛°, --- 17', 4・- Table 1 Here, nitrified cotton is 1/10 seconds, 1/2 seconds, 1/'
Those having a viscosity of 4 seconds (1-1 ercules p, Oder company viscosity display) can also be used.

Then, a 21-ton-shaped base material is immersed in the prepared solution to impregnate the fibers of the pulp forming the base material with the solution, thereby adhering the nitrocellulose solution to the fibers in the base material.

Thereafter, the solvent is volatilized and dried in a dryer using hot air at a temperature of 60° C. to form a film of Nido-0 cellulose fixedly on the surface of the m-line material as a base material and between them.

The base material that has gone through the above steps is cut into a predetermined shape to obtain a speaker diaphragm.

FIG. 1 is a cross-sectional view of the speaker diaphragm of this example obtained in this way, and shows a square-shaped one.

FIG. 2 is an enlarged cross-sectional view of a portion indicated by circle A in FIG. It is sealed with Lurose 2. Therefore, the bond between the fibers 1 is as strong as possible, and the nitrocellulose solution is used to make the bond I
F-eye enhances the effect even more. Further, the fibers 1 are natural fibers or synthetic fibers, and the base material 4 is formed by paper-making one or a mixture of these fibers.

Table 2 shows the physical property values of the diaphragm of this example and the base material that has not been waterproofed yet.

Comparing the two, the diaphragm of this example eliminates the extreme increase in density and increases both Young's modulus and internal loss. I know that there is.

In addition, an air permeability test based on JIS-P8117 was conducted on the diaphragm of the present invention, and the results showed that the 100 cC application time was 53.3 seconds for the untreated diaphragm, while the diaphragm of this example had a Even after 10 minutes, it did not reach 100cc, indicating that sufficient sealing had been done.

Furthermore, Fig. 3 shows the sound pressure frequency characteristic curve A of the speaker using the imaging plate of this example measured under the same conditions, and the output sound pressure of the speaker using the diaphragm made of a base material that is not waterproofed. This is a Gusif that subtracts the frequency characteristic curve B and compares the two. It can be seen that h of the speaker using the diaphragm of this example has little split resonance and a flat output sound pressure frequency characteristic between sound ranges.

In this embodiment, natural fibers will be described, but chemical fibers or composite materials thereof may also be used. In addition, during the papermaking process, the waterproof property can be further improved by adding a 1-nize abrasion to the beating bulb on the inner surface of urea-formaldehyde resin, soubrene-based resin, etc. According to the study, NidoCl Cell 1-1- is hardened at a relatively low temperature, making it difficult to heat-treat the material (
What about the base material? l Mechanical string materials (e.g., those containing synthetic binding strings)
A diaphragm can be obtained which has a degree of 4iiIt which is equal to or higher than that of thermosetting resin, and which is waterproof and water resistant.

It has a sufficient sealing effect even without heating, so
There are no adverse effects from an acoustic standpoint, such as an increase in the density of the base material or a decrease in internal loss, due to hot pressing, and the physical properties of the base material can be fully utilized.

The main surface of the substrate is sufficiently sealed by the hardened aluminum and does not require the waterproofing treatment required for conventional coatings, reducing the number of manufacturing steps. I can do it.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the speaker diaphragm of the present invention, and FIG. 2 is an enlarged cross-sectional view of the part marked with a circle △ in FIG.
FIG. 3 is a graph showing the output sound pressure frequency characteristics of a speaker using the diaphragm according to the present invention. Explanation of symbols of main parts

Claims (1)

[Claims] A diaphragm for a speaker comprising a base material made of natural fibers, chemical fibers, or a mixture thereof, impregnated with a nitrocellulose solution, and dried and hardened.