Magnetic circuit

Abstract

Abstract PURPOSE:To form a magnetic circuit which is small-sized and whose stroke is long by using a cylinder-shaped magnet having a radial anisotropy to function as the counter electrode of a pole piece. CONSTITUTION:A cylinder-shaped magnet 11 having the radial anisotropy is provided concentrically with a pole piece 10. Between the peripheral surface of the magnet 11 and the peripheral surface of the pole piece 10, a magnetic gap 13 in which a voice coil 12 is interposed is formed. Consequently, the mag net 11 functions as the counter electrode to the pole piece 10. Thus, as the length of the magnet 11 is made long, the stroke to linear-drive a coil bobbin 14 to wind a coil 12 can be made long. Since the magnet 11 can be formed to be thin, the maximum outer diameter of the magnetic circuit can be made small.

Inventors

• 👤 Jiro Nakaso

Bibliographic Details