PROCESSES OF MANUFACTURING OF YOKE

摘要

A method for manufacturing a hollow cylindrical magnetic yoke assembly for a magnet-type electric motor, including a plurality of permanent magnets attached to the inner peripheral surface of the yoke. The method comprises the steps of expanding a hollow cylindrical tube of a magnetic material by an expander having a plurality of expander elements capable of being moved radially outwards to expand the radius of the tube. The number of the expander elements is equal to the number of the permanent magnets of the electric motor, and one permanent magnet is fitted to each concaved surface of the magnetic yoke formed by the convexed cylindrical outer surface of each expander element.