| 摘要 |
A low frequency vibrator has a stator member (10) with a cylindrical, centra l chamber (12), a cylindrical, tubular liner of low friction, non-ferromagneti c material (18) positioned in the chamber (12) to form a bearing, and a cylindrical, ferromagnetic, reciprocating piston (20) slidably mounted in th e liner (18). The stator (10) has a pair of coils (30, 32) and a permanent magnet (44) is positioned centrally in the reciprocating piston (20). A ferromagnetic flux conductor surrounds the coils (30, 32) and extends betwee n opposite ends of the chamber (12). This structure creates a magnetic spring, having a spring constant K. The ratio of K to the mass M of the reciprocatin g piston (20) is made substantially equal to the square of a radian frequency in the operating frequency range of the vibrator.
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