| 摘要 |
<p>The invention relates to a vibrator specifically for a hearing aid device of the bone conduction type, i e a hearing aid device by which the sound information is mechanically transmitted via the skull bone directly to the inner ear of a person with impaired hearing. The vibrator comprises a coil (1) for generating a dynamic magnetic field and two permanent magnets (3a, 3b) for generating a static magnetic field. The two permanent magnets (3a, 3b) are working independently from each other in the magnetic circuit and are arranged in such a way that the static and dynamic magnetic fields are substantially separated from each other, but coinciding in the air gaps (6a, 6b) formed between the coil and magnet arrangement and the casing (4), whereby the vibrator provides an axial force (7). Preferably, the entire coil and magnet arrangement is enclosed in a casing (4) which forms a part of the magnetic circuit and protects the vibrator and reduces magnetic leakage.</p> |
