| 摘要 |
PURPOSE:To obtain large connecting force by changing the number of windings in a first layer and a second layer to generate a step at the end part of the second layer of an outside and forming a bobbin covering the step part and protruding according to the injection molding of a resin at the time of butt joining the coil and the bobbin to have a voice coil for a speaker. CONSTITUTION:At the time of forming the voice coil, it is formed to a two-layer structure to make the number of the windings of the coil 5 of the second layer situated an outside smaller than the coil 4 of the first layer situated at an inside and generate the steps at the start of winding and at the end of winding. Thereafter, the bobbin 7 parallel to the internal periphery of the coil 4 of the first layer and the external periphery of the coil 5 of the second layer including the steps is protruded by a prescribed length and injection molded. In such a way, the coil can be previously individually wound, so that the coil can be wound irrespective of the thickness of a bobbin material, further, the connecting area of the coil and the bobbin is increased to obtain the strong connection.
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