JPS607877B2 - voice coil bobbin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a voice coil bobbin for use in a speaker, and particularly to a voice coil bobbin having a structure designed to improve heat resistance and Young's modulus.

In general, a speaker kettle, for example, as shown in FIG. 1, has a magnetic circuit section formed of a magneto, a pole 2, and a yoke 3, and a tube arranged in a gap between the magnetic circuits and around which a voice coil 4 is wound. The voice coil bobbin 5 includes a voice coil bobbin 5 and a cone-shaped diaphragm 6 for extracting mechanical vibrations caused by the audio current flowing through the voice coil 5 as sound. The voice coil bobbin used in speakers is desired to have a high Young's modulus and sufficient rigidity in order to faithfully transmit the mechanical vibrations generated in the voice coil and cause the diaphragm to vibrate. ,
Most of the sound electric particles are converted into heat in the voice coil, and during the operation of the speaker, the voice coil produces 1000 to 150 particles.
Since the temperature rises to about 0, it is necessary to have excellent heat resistance. Conventionally, such a voice coil bobbin has been used, in which a voice coil is wound around a base made of kraft paper, aluminum alloy foil, heat-resistant resin film, or the like into a cylindrical shape.

However, in such a conventional voice coil bobbin,
Materials using kraft paper as a substrate not only have a low Young's modulus and further decrease in Young's modulus due to moisture absorption, but also have extremely poor heat resistance. Furthermore, those using aluminum alloy foil as a substrate have relatively good heat resistance, but cannot obtain a sufficient Young's modulus. moreover,
Those using a heat-resistant resin film as a substrate can obtain good heat resistance, but have a drawback of having a low Young's modulus. Note that a resin film such as polyimide is not used as the heat-resistant resin film, and substrates made of such heat-resistant resin films not only have a significantly lower Young's modulus than metals, but also have extremely thin surfaces. Because the resin itself is smooth and generally inert to solvents, sufficient adhesive force cannot be obtained to wrap the voice coil and fix it with adhesive. Therefore, the present invention aims to improve Young's modulus and heat resistance by vapor-depositing a highly elastic metal on the surface of the base and then wrapping and fixing the voice coil. It is an object of the present invention to provide a voice coil bobbin that can be fixed in place.

Hereinafter, the present invention will be described in detail using drawings showing one embodiment.

First, a first embodiment of the voice coil bobbin according to the present invention will be described in accordance with its manufacturing process using FIGS. 2A to 2D.

In this embodiment, a heat-resistant resin film such as polyimide, polyamide, imidamide, polyester, etc. is used as the substrate 10.

As shown in FIG. 2A, the film-like base 10 is coated with a highly elastic metal such as boron B, poron carbide B4C, silicon carbide SIC, or titanium carbide TIC on one side 10a by ion plating or sputtering. One side 10a is covered with a metal layer 11 as shown in FIG. 2B. Next, as shown in FIG. 2C, this base body 10 is formed into a cylindrical shape with the metal layer 11 on the outside to form a bobbin 12. Furthermore, as shown in FIG. 2D, the voice coil 13 is wound around the bobbin 12 formed in this manner and fixed with an adhesive 14, thereby obtaining a first embodiment of the voice coil bobbin according to the present invention. It will be done. In the first embodiment as described above, the Young's modulus of the heat-resistant resin film forming the base 10 is relatively small, but the Young's modulus is reduced by the high elastic metal layer 11 formed on one side 10a of the base 10. is increased and bobbin 12
A sufficient Young's modulus can be obtained as a whole.

In addition, the high elastic metal layer 1 formed by the above vapor deposition
1 is rougher than the surface of the heat-resistant film, so the voice coil 14 can be fixed with a large adhesive force using an adhesive. Furthermore, since the entire bobbin 12 is formed of the heat-resistant resin film base 10 and the highly elastic metal layer 11, sufficient heat resistance can be obtained. Next, a second embodiment of the voice coil bobbin according to the present invention will be described using FIG. 3 showing a cross-sectional view thereof.

That is, in this second embodiment, a voice coil 13 is wound around a bobbin 12 which is formed by forming a base body 10 made of a heat-resistant resin film into a cylindrical shape, on both sides of which a highly elastic metal layer 11 is formed by vapor deposition. It is fixed with adhesive 14. In such a second embodiment, since the highly treadable metal layer 11 is formed on both sides of the base 10, the Young's modulus can be further improved than in the above-mentioned first embodiment.

In each of the above-mentioned examples, a heat-resistant resin film was used as the substrate, but it is also possible to use kraft paper, aluminum alloy foil, etc. as the substrate and form a soaring metal layer on the surface by vapor deposition. It is possible to improve the

Furthermore, since the metal layer improves heat dissipation, heat resistance can also be improved. In particular, if the structure is as in the second embodiment above, even if kraft paper is used as the base, the base will be completely covered with the metal layer, so the moisture resistance of the base will be improved, and the Young's modulus will increase. In addition, a voice coil bobbin with sufficient heat resistance can be realized. Table 1 shows the respective densities p and Young's modulus E of polyimide and aluminum alloy 5$, which are the materials of the base, and boron carbide &C and poron B, which are high elastic metals. Table 1
Table showing physical properties of base body and metal layer materials As is clear from the description of each of the above-mentioned examples, according to the present invention, a bobbin in which a highly elastic metal layer is formed on the surface of a base body by vapor deposition,
By providing a voice coil bobbin characterized by having a structure in which a coil is wound, the Young's modulus and heat resistance of the entire bobbin can be improved due to the highly elastic metal layer.

Furthermore, even if a heat-resistant resin film is used as the base, the voice coil can be fixed with sufficient adhesive force using an adhesive. Therefore, if the voice coil bobbin according to the present invention is applied to a speaker, it becomes possible to faithfully transmit the mechanical vibrations generated in the voice coil to the diaphragm and radiate acoustic output with excellent acoustic characteristics. Furthermore, since the voice coil bobbin has excellent heat resistance, it becomes possible to provide a high-output speaker. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an example of the structure of a speaker to which the present invention is applied.

FIGS. 2A to 2D are sectional views of the first embodiment of the voice coil bobbin according to the present invention in the order of manufacturing steps. FIG. 3 is a sectional view showing the structure of a second embodiment of the present invention. 10... Base body, 11... Highly elastic metal layer, 12... ...Bobbin, 13...Voice coil, 14...Adhesive.

Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. A voice coil bobbin characterized by having a structure in which a coil is wound around a bobbin made of a highly elastic metal formed by vapor deposition on the surface of a base body. 2. The above-mentioned method is characterized in that a heat-resistant film such as polyimide, polyamide, amide-imide, or polyester is used as a base material, and a highly elastic metal such as boron carbide, silicon carbide, titanium carbide, etc. is vapor-deposited on the surface of the base material. A voice coil bobbin according to claim 1.