| 摘要 |
PURPOSE:To assure lightweightness and to form a head shell which has no possibility of inducing partial resonance by sintering and molding metallic short fibers. CONSTITUTION:The head shell 4 is formed by sintering and molding the short fibers of, for example, Al (aluminum) Ti (titanium), Be (beryllium), Fe (iron), etc. The term 'short fibers' refers to the fibers of <=5000 l/d if the outside diameter and length of the fibers are designated as (d) and l. The short fibers of d=50-100mum, l=3-5 mm Ti are used in this head shell 4. Since many open pores 4b exist in the sintered molding, the specific gravity is as small as about 2.2 and the value of such specific gravity is fairly low as compared with 2.7 specific gravity of Al and 4.5 specific gravity of Ti. The mechanical strength and rigidity of said molding are equal to or higher than the mechanical strength and rigidity of, for example, Ti as the molding is formed by sintering the fibers. The sound absorption coefft. (shown by a solid line 8) of the sintered short fiber body is in the frequency range from middle to high frequency ranges and is larger than the sound absorption coefft. of the conventional Al (shown by an alternate long and short dash line 9). |
