| 摘要 |
PURPOSE:To eliminate a bad influence of adhesives used for the voice coil and to obtain a voice coil for a speaker which is excellent in the heat resistance by installing a small pore at a non-porous bobbin material and making the material ventilative. CONSTITUTION:At a sheet (metallic foil and heat resistant sheet), which is a bobbin material, the pores are made mechanically. A bobbin material 9 is the one which has the pore 6, and a reinforcing paper 2 is composed of a craft paper, etc. A hole diameter of the pore is phi0.1-phi2, the most desirable hole diameter is phi0.3-phi0.5, a pore ratio is 3%-50%, desirably about 5-10% is satisfactory, at the pore ratio of 3% or below effects are little (gas drainage) and at 10% or above the bobbin strength is weakened. |
