REPULSION-TYPE MAGNETIC CIRCUIT AND SPEAKER DEVICE

摘要

A repulsion-type magnetic circuit in which deterioration of magnetic characteristics of magnets caused by heat accumulation in the magnets can be suppressed. The repulsion-type magnetic circuit constituted by placing a magnet and a plurality of magnets with their like poles facing each other comprises a yoke, a pole piece, and a top plate. The pole piece is placed above the yoke, the top plate is placed above the pole piece, the magnet is placed between the yoke and the pole piece, and particularly the plurality of magnets are placed between the pole piece and the top plate.This makes it difficult for Joule heat generated from a voice coil to be transmitted as radiation heat to a magnet closer to the top plate out of the plurality of magnets. Consequently, even if the radiation heat continues being transmitted to the pole piece when the voice coil is driven over a long time, the temperature of the magnet on the top plate side is difficult to increase. Thus, the plurality of magnets can be prevented from being demagnetized, so that deterioration of magnetic characteristics thereof can be suppressed.