JPS59169298A - Speaker diaphragm - Google Patents

Abstract

PURPOSE:To obtain a speaker which has a flat sound pressure-frequency characteristic by applying a heat expansion treatment on the surface of a diaphragm material containing fiber to obtain an independent porous layer and a binder film covering said porous layer. CONSTITUTION:A speaker cone is manufactured to sheets by crushing with adjustment the KBKP pulp. The heat expansion component uses 10-30pts.wt. hydrocarbon of a low boiling point containing a vinylidene chloride coplymer as a shell wall, and a binder uses 100-200pts.wt. self-crosslinkage type water solble resin. These heat expansion component and binder are dissolved into 400- 600pts.wt. water, i.e., solvent by means of a disaggregating machine. Furthermore 10-30pts.wt. saturated zinc chloride solution is added to said solvent to improve the smoothness properties. such a solvent is sprayed to the diaphragm material of a speaker by a spray gun, etc. This diaphragm material is heated at 120- 140 deg.C for three minutes after a preliminary drying process carried out at 60- 80 deg.C within a hot air drying machine together with the addition of pressure when necessary. Thus an independent porous layer 2 and a binder film covering the layer 2 are formed on the surface of a speaker diaphragm.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speaker diaphragm that can appropriately reduce internal acoustic loss.

In general, the performance required for speaker diaphragms is as follows:
It has a high elastic modulus, a small specific gravity, a high propagation speed as a result, and a moderately large internal loss.

Conventionally, paper has been the main material for such speaker diaphragms, but with the aim of creating materials with even higher elastic modulus and lower specific gravity, foamed resins, metals such as aluminum, and composite materials of metals and polymeric feeds have been used. etc. also began to be used.

However, a high modulus of elasticity cannot be expected with foamed resin, and it is difficult to maintain an appropriate acoustic internal loss with metals or composites of metals and polymer materials, so the sound pressure-frequency characteristics may not be flat. First, it had the disadvantage of causing split resonance in the high frequency range.

An object of the present invention is to provide a diaphragm for a speaker that can overcome the drawbacks of the above-mentioned conventional techniques, can moderate acoustic internal loss, and can therefore flatten sound pressure-frequency characteristics. It is in.

The present invention will be specifically described below based on Examples.

■Paper production of speaker diaphragm material Beat N B K P pulp and adjust the beating degree to 20°SR as a raw material, and form it into a speaker cone shape as shown in Figure 1 (A>).

■Adjustment of thermal expansion agent 10 to 30 parts by weight of a low-boiling hydrocarbon encapsulated with vinylidene chloride copolymer as a shell wall as a thermal expansion component, and 100 to 200 parts by weight of a self-crosslinking water-soluble resin as a binder. It is dispersed in 400 to 600 parts by weight of water as a solvent using a disintegrator. To this, 10 to 30 parts by weight of a saturated zinc chloride solution is added in order to improve smoothness.

Note that depending on the material of the speaker diaphragm, a thermosetting resin such as melamine resin may be used as the binder, and methanol or the like may be used as the solvent.

For example, if the material of the speaker diaphragm is not paper but vinyl chloride resin mixed with carbon fiber, use 1 part by weight of melamine resin as the binder, 10 parts by weight of methanol as the solvent, and remove the thermally expandable component. However, it can be used by dispersing it in a ratio of 12:1 by weight.

(2) Adhesion of the above-mentioned solvent to the speaker diaphragm material. For example, use a spray gun to apply the solvent from a distance of 40 to 5 Qcm. In this case, it may be attached to the entire surface as shown in FIG. 1(B), or it may be partially attached as shown in FIG. 1(D).

Furthermore, when an organic solvent such as methanol is used as the solvent, it may be impregnated.

■Drying After pre-drying at 60-80℃ in a hot air dryer, 120-1
Heat at 40°C for 3 minutes. Also, if necessary, 1.0
~3.0 kg/crl may be pressurized.

In this way, a sliding plate for a speaker according to the present invention as shown in FIG. 1(C) or (E) is manufactured.

Figure 2 (A) corresponds to Figure 1 (C), and Figure 2 ('B)
is a partially enlarged view.

In the figure, 1 is wood pulp, 2 is an independent porous layer, and 3 is a binder coating.

Also, Figure 3 (A) corresponds to Figure 1 (A), and Figure 3 (A) corresponds to Figure 1 (A).
B) is a partially enlarged view.

In this way, the speaker diaphragm material before treatment (Figure 3)
However, by the treatment according to the method of the present invention, an independent porous layer 2 and a binder film 3 covering the independent porous layer 2 are formed on the surface of the speaker diaphragm as shown in FIG.

As a result, as shown in the following table, the speaker diaphragm according to the present invention has a small change in elastic modulus and propagation velocity, and can have a large internal loss (tan δ).

Therefore, as shown in FIG. 4(B), a speaker diaphragm with flat sound pressure-frequency characteristics can be obtained (FIG. 4(A) is the diaphragm before treatment).

Furthermore, by changing the amount of solution attached, the value of internal loss can be controlled as shown in FIG.

Furthermore, by changing the types of binder and solvent and their component ratios, we have created a vibration 1
On the contrary, the present invention can be applied.

[Brief explanation of drawings]

FIGS. 1(A)-H(E) are cross-sectional views of a speaker cone for explaining the manufacturing method of the present invention, FIGS. 2(A) and (B)
is a sectional view of the speaker diaphragm of the present invention, FIG. 3(A) (
B) is a sectional view of a speaker diaphragm before treatment according to the present invention, FIGS. 4(A) and 4(B) are sound pressure-frequency characteristic diagrams, and FIG. 5 is a solution adhesion rate-internal loss curve diagram. 2...Independent porous layer, 3...Binder coating. Figure 1 (A) (B)

Claims (1)

[Claims] A diaphragm for a speaker, which is formed by subjecting the surface of a diaphragm material containing natural fibers, synthetic fibers, inorganic fibers, etc. to thermal expansion treatment to form an independent porous layer and a binder film covering the independent porous layer.