ELECTRIC MOTORS

摘要

The invention relates to permanent magnet rotor brushless high performance servo motors and to the design and manufacture of such motors making efficient use of high energy product magnets having an energy product in excess of 20 MGOe. The interpole distance to the radial air gap is greater than 1.3 and the ratio of permanent magnet length to air gap length is in the range of from 0.5 to 2.0. The winding is arranged in the air gap and secured to the inner surface of the slotless back iron cylindrical stator shell by encapsulation in a resin having a flexural strength of at least 140 kg/cm<2> at 250 DEG C and high thermal conductivity and a coefficient of thermal expansion in the range of the other materials of the stator structure. The stator winding is formed on a cylindrical temporary support with reduced diameter on one side using preformed coils. The end turns at the end of the temporary support with reduced diameter flare inwardly, whereas the end turns at the other end flare outwardly. The support with the winding is inserted into the stator shell starting with the inwardly flared end turns and is withdrawn from the side of the stator shell with the outwardly flared end turns. The motor of the invention, compared to a servo motor of approximately the same physical dimensions, produces an increase of about 70% in continuous performance and with respect to intermittant performance an increase of 80% with only 30% increase of the permanent magnet material.