Electrical audio signal processing systems and devices – Electro-acoustic audio transducer – Electromagnetic
Reexamination Certificate
2006-12-12
2006-12-12
Le, Huyen (Department: 2615)
Electrical audio signal processing systems and devices
Electro-acoustic audio transducer
Electromagnetic
C381S412000, C381S420000
Reexamination Certificate
active
07149323
ABSTRACT:
A speaker comprising: a magnetic circuit provided with a through hole, and a recess formed around the through hole for retaining a magnetic fluid. The speaker further comprises a bearing provided in the through hole and a shaft supported by the bearing to be movable up and down and fixed to a center cap fixed to a voice coil. A gap between the bearing and the shaft is filled with the magnetic fluid. The speaker eliminates a damper, and realizes a very low f0which has not been obtained before. Furthermore, the magnetic fluid absorbs friction and resonance between the bearing and the shaft, and the magnetic fluid is kept in the recess and is supplied smoothly into the gap between the shaft and the bearing. Thus, generation of abnormal sounds is suppressed and a large amplitude operation is realized in the speakers of the present invention.
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Le Huyen
Matsushita Electric - Industrial Co., Ltd.
Wenderoth , Lind & Ponack, L.L.P.
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