MOVING CORE LINEAR ACTUATOR

摘要

To provide a movable iron core linear actuator capable of properly adjusting an offset position without any increase in manufacturing cost or device size. A movable iron core linear actuator includes a magnetic circuit (mc) which causes a moving element (2) to reciprocate. The magnetic circuit (mc) includes an iron core (20) constituting the moving element (2), a stator core (10) including a facing portion (10c) which faces the iron core (20), a pair of permanent magnets (12a, 12b) disposed in the facing portion (10c) along a reciprocating direction and having inverted magnetic poles at their surfaces which face the iron core, and a coil (11) wound around the stator core (10). Energization to coil (11) causes the moving element (2) to reciprocate. When the coil (11) is not energized, offset force (F4) is applied to the moving element (2) by the magnetic flux produced by the permanent magnets (12a, 12b). A space portion (30) having low magnetic permeability compared with the stator core (10) is provided in a state in which a part of the facing portion (10c) is removed in an area, which is a magnetic flux path, between a part of the facing portion (10c) of the stator core (10) and the permanent magnet (12b). Thus, an offset position which is a balanced point of the gravity (mg) acting on the moving element (2) and the offset force (F4) by the permanent magnets (12) is changed to a position (ps2) from a position (ps4) that is the offset position in a case in which no space portion (30) is provided.