| 摘要 |
PURPOSE:To reduce magnetic resistance and to improve efficiency of the entitled speaker by winding a primary coil and voice coil around a fixed iron core having a pair of magnetic core parts which are symmetrical to the axis of a speaker cone and parallel to the axis each other and providing the voice coil with a fixed magnetic field. CONSTITUTION:Primary coils 13a, 13b for inputting voice signals are wound around a fixed iron core 11 having magnetic core parts 11a, 11b which are symmetrical about the axis of a speaker cone 12 and parallel to the axis each other so that the current directions of both the primary coils are reversed each other. Voice coils 14a, 14b consisting of D shaped conductive rings are contacted to the magnetic core parts 11a, 11b so that the inner sides are contacted each other and a contact part between the cone 12 and a dumper 15 is adhered to the upper periphery of the round voice coil formed by uniting both the coils. Parmanent magnets 16a, 16b for providing a fixed magnetic field, field plates 17a, 17b and a magnetic york are attached to the outside of both the voice coils 14a, 14b. |
