Method of and apparatus for covering rotor magnets

A method of covering permanent magnets of a rotor with a cylindrical member, comprising the steps of:

• providing a rotor with opposite ends and having a plurality of permanent magnets thereon which are spaced at given angular intervals around said rotor;
• forcing a holding jig having a plurality of grooves of inserting said permanent magnets therein and a plurality of tapered teeth, together with a movable jig, into an insertion end of the cylindrical member, whereby said teeth expand said cylinder member at said insertion end radially outwardly to a diameter greater than a diameter of the rotor, wherein a largest outer diameter of said movable jig is greater than an interior diameter of said cylindrical member when the cylindrical member is in a non-expanded state;
• inserting said rotor together with said movable jig into said cylindrical member while being guided by said holding jig, wherein said movable jig further expands the cylindrical member with said rotor having one of said opposite ends continuously engaging and forcing said movable jig during the insertion;
• and
• after said rotor has been inserted in said cylindrical member, removing said holding jig and said movable jig from said opposite ends of said rotor, for thereby leaving said permanent magnets covered with said cylindrical member.