JPH0113518Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a speaker diaphragm manufactured by paper-making a pulp-like fiber raw material.

Conventionally, this type of speaker diaphragm has been characterized by having an internal structure as shown in FIG. In the figure, 1 is a natural fiber consisting mainly of vegetable fibers and animal fibers added as needed, and the natural fibers 1 are intertwined with each other, and a suitable binder, filler, sizing agent, dye, etc. Paper 2 is made by adding .

As mentioned above, this type of speaker diaphragm has a low density due to many voids, and has a three-dimensional structure mainly consisting of intertwined fibers, so it suffers from large losses due to friction against the propagation of mechanical vibrations. be.
The low density allows the speaker diaphragm to be lightweight, contributing to increasing the efficiency of converting electrical energy input into the speaker into acoustic energy, and also increasing the thickness of the diaphragm to reduce vibration. By increasing the rigidity of the plate against bending deformation, it contributes to expanding the reproduction frequency band of the speaker and reducing harmonic distortion during reproduction. Furthermore, the large loss caused by the propagation of mechanical vibrations damps the resonance of the diaphragm itself and contributes to flattening the peaks and dips caused by the resonance of the diaphragm in the reproduced sound pressure of the speaker.

The above are the features of conventional speaker diaphragms of this kind, but in recent years, as part of the improvement in the performance of audio playback devices, speakers are also required to have a wider band and lower distortion, and speaker diaphragms are required to have a wider band than before. Papers made of natural fibers 1 are required to have high rigidity, but there is a limit to the Young's modulus that can be achieved with paper 2 made from natural fibers, and the increase in rigidity due to the effect of thickness is insufficient to meet the requirements. There is.

In order to achieve higher rigidity, light metals that have been used in the past, such as aluminum, magnesium, and titanium, have relatively good workability, and beryllium and boron, which have extremely low workability but have extremely high Young's modulus. Materials such as beryllium and boron have been used, but they are inferior to paper in terms of weight and internal loss, and materials using beryllium and boron are significantly more expensive than paper.

Alternatively, the raw material for paper 2 can be not only natural fiber 1, but also synthetic fibers with higher Young's modulus such as nylon, inorganic fibers such as glass fiber, carbon fiber, and boron fiber, and metal fibers such as beryllium and molybdenum. Artificial fibers have been mixed in to increase the Young's modulus of paper 2, but in general, artificial fibers have a smooth surface and are easy to intertwine with other fibers, as shown in 3 in Figure 2. The problem is that it is not very effective in increasing the Young's modulus of paper 1 because it has a poor quality and cannot act effectively as part of the structure of paper 1, and the proportion of artificial fibers cannot be increased too much. It was hot.

This idea was made in order to eliminate the drawbacks of the conventional ones as mentioned above, and by mixing atomized boronized fibers produced in a boron atomized body with the raw material and making paper, it is possible to achieve low density and high internal loss. The aim is to manufacture a speaker diaphragm that has both high rigidity.

This idea will be explained below with reference to the figures.

FIG. 3 shows the appearance of the fume boronized fiber 4. FIG. 4 shows an example of an apparatus for producing boronized fiber 4.
In FIG. 4, 5 is a vacuum chamber formed of a heat-resistant container, 6 is an exhaust port provided at the top of the vacuum chamber 5,
7 is a gas distribution plate having a large number of fine through holes, 8
9 is a filter located at the upper part of the vacuum chamber 5 and has a large number of fine through holes; 9 is a gas generating substance such as aluminum or magnesium whose vapor has a cyclic property;
10 is a gas generating furnace that performs heating to evaporate the gas generating substance 9; 11 is a boron fume in which amorphous boron fine powder is suspended as colloidal particles;
12 is a fiber made of carbon, titanium, or the like cut to an appropriate length to be mixed into the pulp; 13 is a heater for heating the vacuum chamber 5; Although the fine through holes of the gas distribution plate 7 and the filter 8 allow the vapor of the gas generating substance 9 to pass therethrough, the boron fumes 11
However, the size is such that it is impossible for the fibers 12 to pass through.

Next, the process of producing the atomized boronized fiber 4 using the apparatus shown in FIG. 4 will be explained. Boron powder and fibers 12 are layered on the gas distribution plate 7, and the exhaust port 6
When the air in the vacuum chamber 5 is evacuated using an external vacuum pump device and the gas generating substance 9 is evaporated from the gas generating furnace 10, the steam passes through the gas distribution plate 7 and forms a layer of boron powder and fibers 12. The boron powder blows up and becomes colloidal boron smoke 11. In this state, when the inside of the vacuum chamber 5 is heated to about 1000°C by the heater 13, boron atoms diffuse and permeate the surface of the fiber 12 at the part of the fiber 12 that is in contact with the boron fume 11, as shown in FIG. A fume boronized fiber 4 having an uneven surface as shown is obtained.

As mentioned above, since the atomized boronized fiber 4 has an uneven shape on its surface, when it is mixed into pulp and paper is made, the intertwining between the fibers is good, and at the same time, the Young's modulus is also reduced due to the diffusion of boron. This has the effect of increasing the contribution to increasing the Young's modulus of the paper. Also,
Needle-like crystal whiskers can also be used as the fibers 12, and the excellent properties of whiskers can be utilized as a speaker diaphragm.

[Brief explanation of the drawing]

Figure 1 is a partially enlarged view showing the structure of a speaker diaphragm made using a conventional paper-making method, Figure 2 is a partially enlarged view showing the appearance of the artificial fiber, and Figure 3 is the atomized boronized fiber used in this invention. FIG. 4 is a partially enlarged view showing the appearance of the fume boronated fiber. 2...Paper, 4...Atomized boronized fiber. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims for Utility Model Registration] (1) Atomized boronized fibers that are produced by heating carbon or metal fibers in a boron atomized body in which fine boron particles are suspended in a colloidal state, and which have irregularities on the fiber surface. A speaker diaphragm characterized by being made of paper made by mixing the following into raw material pulp. (2) The speaker diaphragm according to claim 1, wherein the metal is titanium. (3) The speaker diaphragm according to claim 1 or 2, wherein the fibers are whiskers.