PURPOSE: To improve the heat dissipation of the coil and to prevent the open wire of leads, by making small the magnetic circuit through the combination of moving magnet locating the cone in oscillation free, to the core having special shape coil.
CONSTITUTION: The entire core 10 of moving magnet type speaker is almost formed in bobbin shape, the sectional area is made almost to I-shape, and it is fixed to a suitable frame. The ring shape groove 11 is formed around the core 10, and the magnetic legs in flange shape are formed at the both ends of the core 10 with the groove 11, and the exciting coil 12 is wound in the groove 11 so that the magnetic legs upper and lower can be magnetized to different poles. Further, the projection 13 is formed at the inner tip of the magnetic legs to improve the magnetic flux flowing to the magnetic circuit. Further, the moving magnet 14 high in the coercive force and light in weight is located around the core 10, and this moving magnet 14 is opposed with slight gap upper and lower to the core 10 in oscillation free. Further, the magnetic circuit is made small in size to improve the heat dissipation of the coil 12 and to prevent the open wire of the leads.
| JPS6019099 | [Title of the device] Electromagnetism type sound converter |
| WO/2022/153915 | BONE CONDUCTION DEVICE |
IWABUCHI MASASUKE
NAKAMURA EIICHI
