Patent ID: 6924722
Filing Date: 2005-08-02
Classification: G01R,H01F

Abstract:
1. A magnetic circuit with opposing permanent magnets, comprising: a pair of permanent magnet units opposing each other across gap, the pair of permanent magnets being magnetized in thickness direction, wherein each of the permanent magnet units comprises at least two types of permanent magnet pieces with different coercive forces, and wherein, the permanent magnet piece that receives the largest demagnetization force when the permanent magnet units are manufactured has a larger coercive force than at least one other type of the permanent magnet piece; a yoke magnetically coupled to the permanent magnet units, and provided outside of the permanent magnet units and the gap; and a pair of pole pieces each arranged on a gap side of an opposing surface of each of the permanent magnet units and having a peripheral projection in opposing direction.