Electric machine with linear mover

An electric machine comprising:

• a stator;
• a mover capable of reciprocal linear motion in an axial line direction with respect to the stator,
• one of the stator and the mover including a permanent magnet array including a plurality of permanent magnets arranged such that magnetic poles having the same polarity directly face each other in the axial line direction,
• the plurality of permanent magnets in the permanent magnet array include two permanent magnets that are magnetized in the same direction of the axial line and one permanent magnet having a different polarity being interposed between the two permanent magnets;
• the other of the stator and the mover including one or more winding portions formed by winding a winding conductor in a coil and concentrically disposed with the permanent magnet array;
• and
• a magnetic pole piece array including a plurality of magnetic pole pieces which are disposed between the permanent magnet array and the one or more winding portions in immovable relation with the winding portions and are spaced along the permanent magnet array, characterized in that:
• a pitch of the plurality of permanent magnets and a pitch of the plurality of magnetic pole pieces are determined such that magnetic flux flows through two of the permanent magnets magnetized in the same direction of the axial line and located in the permanent magnet array with one permanent magnet interposed between the two permanent magnets, and also flows through one of the magnetic pole pieces facing the one permanent magnet interposed between the two permanent magnets and magnetized in a direction different from the direction of magnetization of the two permanent magnets.