Patent ID: 7276820

Claim:
A movable assembly for a cylinder type linear motor, the cylinder type linear motor having a movable core fixed to one or more direct drive shafts and capable of performing a reciprocal, linear motion; wherein the one or more direct drive shafts each have a yoke mounting portion to which the movable core is fixed and a pair of supported portions situated at both axial ends of the yoke mounting portion and supported by bearings; wherein the direct drive shafts are so shaped that the yoke mounting portion has a smaller cross section orthogonal to the axial direction than that of the supported portions; wherein the movable core is constructed of a laminated yoke which is formed of a plurality of electromagnetic steel plates laminated in an axial direction of the direct drive shafts; wherein the electromagnetic steel plates are each constructed of a plurality of divided electromagnetic steel plate pieces; wherein the divided electromagnetic steel plate pieces are so shaped, when combined to enclose the one or more direct drive shafts, as to be able to form one of the electromagnetic steel plates that constitutes one layer of the laminated yoke; wherein the one or more direct drive shafts are first and second direct drive shafts arranged parallel to each other; and, wherein the divided electromagnetic steel plate pieces are in the same shape.