Patent ID: 6853100

Claim:
A linear actuator comprising: a first yoke part; a second yoke part opposing the first yoke part from a direction perpendicular to the axial direction thereof; an intermediate yoke part forming a first gap and a second gap, which provides a distance from the second yoke part side in the axial direction, passes both sides, and provides a distance relative to the first yoke part; a coil disposed within a space delineated by the intermediate yoke part and the second yoke part, which forms a magnetic field between the first yoke part and the intermediate yoke part, the orientation of which is opposite between the first gap and the second gap, and which alternates the orientation of the magnetic field; a magnet disposed at one axial-direction end relative to the coil, which generates a fixed magnetic field in the first gap and the second gap, directed either from the intermediate yoke part toward the first yoke part or from the first yoke part toward the intermediate yoke part; and an armature provided with a magnetic body, disposed so as to be movable in the axial direction in the first gap and the second gap.