Abstract: A permanent magnet synchronous motor is of a rotating magnetic field type, and includes a stator which generates a rotating magnetic field, and a rotor having fixed magnetic poles. The rotor includes first and second rotor units arranged axially thereof. The first and second rotor units each have a rotor core, and permanent magnet pieces bonded on the outer peripheral surface of the rotor core. The rotor cores of the first and second rotor units are engaged with each other. The rotor cores each have pin insertion holes into which guide pins are inserted to position the rotor units in proper circumferential positional relation with respect to each other when the rotor cores are connected to each other by bolts.

Abstract: The present invention relates to an offset apparatus for an NC machine tool, that can achieve high accuracy machining by offsetting the amount of operation of a motion mechanism in accordance with the analysis result of the behavior of the NC machine tool. The offset apparatus 1 comprises: a model analyzing data base 12 in which three dimensional model data of the motion mechanism 2 and condition data for performance analysis are stored; a model analyzing section 13 which analyzes the performance of the motion mechanism 2; a data accumulating section 14 which stores analyzed performance analysis data; an offset amount computing section 15 which computes an offset amount to be applied to a commanded operation amount on the basis of the performance analysis data; and an offset executing section 17 which offsets the amount of operation of the motion mechanism 2 on the basis of the offset amount.

Abstract: An actuation member (B) supported by a housing (A) is actuated for clamping upwardly by means of a spring force and actuated downwardly for unclamping by means of an actuation means (D). A piston (11) is inserted into a cylinder (10) fixedly secured to the upper portion of the housing (A), and a liquid sealing chamber (12) is formed below the piston (11). The piston (11) is fixedly secured to the actuation member (B). When the actuation member (B) is held in the clamped condition, a liquid sealing valve (15) is closed so as to seal an oil (L) within the liquid sealing chamber (12). Whereby, in case that a pulling down force larger than the clamping spring force is imposed to the actuation member (B), a pressure generated within the liquid sealing chamber (12) serves to prevent the piston (11) from lowering, against the pulling down force.