Patent ID: 7593540
Filing Date: 2009-09-22
Classification: H01F,H04R

Abstract:
1. A magnetic circuit unit comprising: a first magnet having one end magnetized to one of a north pole and a south pole and an other end magnetized to be opposite in polarity to the one end of the first magnet; a second magnet juxtaposed to and spaced apart from the first magnet, the second magnet having one end and an other end that correspond to the one end and the other end, respectively, of the first magnet, the one end and the other end of the second magnet being magnetized to be opposite in polarity to the one end and the other end, respectively, of the first magnet; a yoke having a plane surface fixedly engaged with the one end of the first magnet and the one end of the second magnet and magnetically coupling together the one end of the first magnet and the one end of the second magnet; a first top plate mounted on and magnetically coupled to the other end of the first magnet; and a second top plate mounted on and magnetically coupled to the other end of the second magnet with the second top plate spaced apart from the first top plate; a magnetic gap formed between the first top plate and the second top plate, and a thickness of the first magnet between the one end and the other end thereof and a thickness of the second magnet between the one end and the other end other being smaller than a width of the magnetic gap.