| 摘要 |
PURPOSE:To prevent the leakage of a low magnetism in a speaker and to freely design a dumper sticking surface by making the diameter of said surface larger and duplicatedly shielding the outer periphery part of a magnetic circuit part with the shield part and leading part of a frame. CONSTITUTION:The center part 16a in the bottom part of the frame 16 is jointed to the upper surface of the magnetic circuit part 15, and the shield part 16b which projects downward so as to cover the outer periphery of the magnetic circuit part 15 is installed on the periphery part of the center part 16a in the bottom part of the frame 16. The outer periphery part of the shield part 16b is again led to joint the periphery part of a diaphragm 18. The outer periphery part of the magnetic circuit part 15 is coverd with the shield part 16b of the frame 16 and the leading part 16c of the outer periphery, and a closed magnetic path consisting of the shield part 16b, the leading part 16c and the magnetic circuit part 15 can substantially reduce the leakage of the magnetism from the magnetic circuit part 15. If the scale of the bottom center part 16a and the diameter of the dumber sticking part 16d are appropriately selected, the scale of a dumper 21 can be freely designed.
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