| 摘要 |
PROBLEM TO BE SOLVED: To realize a multifunctional acoustic device in which the quality of sound, music or the like is not degraded even in the case of simultaneous excitation of a low frequency signal and a high frequency signal. SOLUTION: A columnar top yoke 104 which has a rotor shaft 106 and a freely rotatable rotor 200 set on a speaker magnet 105 and is made of a magnetic material to constitute the inner peripheral part of a speaker space 103 which has the outer peripheral part engaged with a voice coil 102 is fixed in the center part of a lower yoke 108 like a hollow disk made of a magnetic material, and a cylindrical side face yoke 109 made of a magnetic material is arranged in the outer peripheral part of the lower yoke 108 so as to face the outer peripheral part of the top yoke 104 with the speaker space 103 between them, and a pair of a rotor upper permanent magnet 201 and a rotor lower permanent magnet 202 which are magnetized with plural poles in the perpendicular direction are provided on upper and lower faces of the side face yoke 109 with a motor space 301 between them, and driving coils 114 and 115 are arranged in parallel in the motor space 301 to constitute a stator 300, and a weight 203 is arranged on the rotor 200 off the center of the rotor shaft 106 so that a large vibration exciting force may be generated by centrifugal force.
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