| 摘要 |
PROBLEM TO BE SOLVED: To prevent the rolling of a diaphragm by providing an air bearing near the inner diameter or outer diameter of a voice coil bobbin. SOLUTION: A voice coil 8 wound on the voice coil bobbin 9 is inserted into a magnetic gap part 4 formed between the inner diameter of a second plate 6 and the outer diameter of a center pole 3a, the inner diameter part of a damper 14 is stuck to the outer diameter part of the voice coil bobbin 9, the outer diameter part of the damper 14 is stuck to the bottom surface outer diameter part of a frame 5 and the voice coil 8 is pivotally attached in a vertical direction inside the magnetic gap part 4. A gap width between the inner diameter of the voice coil bobbin 9 and the outer diameter of the center pole 3a is adjusted to a dimension for generating the fluid (thin flow) of air at a high speed. By making the thin flow flow near the inner and outer diameters of the voice coil bobbin 9, the inner and outer diameter side of the voice coil bobbin 9 is held by the air bearing, the rolling of the diaphragm is prevented and the rolling is not generated even by a large input by the pressure of the thin flow corresponding to acoustic signal input.
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