An object of the present invention is to provide a linear actuator in
which reliability is improved, and performance is also easily improved.
The present invention provides a linear actuator including a stator, a
movable element having an iron member, and being reciprocatable with
respect to the stator, a permanent magnet fixed to the stator so as to be
opposed to the iron member, and a coil fixed to the stator. Because both
the coil and the permanent magnet are fixed to the stator, electrical
current does not have to be supplied to the movable element, and the
feeder lines connected to the coil will not be broken due to the movement
of the movable element. In addition, the weight of the movable element
will not be increased even when the weigh of the permanent magnet is
increased in order to obtain high magnetic flux density for improvement
in performance. Moreover, because the movable element does not include a
magnet, a magnetizing operation does not have to be applied to the
movable element. The permanent magnets may be a pair in which the
directions the magnetic poles thereof differ from each other, and two
pairs of permanent magnets may be provided. The number of magnetic fluxes
that run through the magnetic pole elements and the iron member can be
increased by providing a magnetic reluctance section around the permanent
magnets.