Abstract: The present invention relates to a piercing apparatus and a piercing method which drive a punch. The piercing apparatus includes a local heating device for heating part of the workpiece in a temperature range less than a melting point of the workpiece and a punch driving device for driving the punch toward the part of the workpiece which was heated by the local heating device. The piercing method includes a local heating step for heating part of the workpiece in a temperature range less than a melting point of the workpiece and a stamping step for driving the punch toward the part of the workpiece which was heated in the local heating step.

Abstract: A stator includes a hollow cylindrical stator core, a stator coil and an outer cylinder. The stator core is comprised of a plurality of core segments that are arranged in a circumferential direction of the stator core to adjoin one another in the circumferential direction. The stator coil is mounted on the stator core. The outer cylinder is fitted on a radially outer periphery of the stator core. The outer cylinder has, at least, a protruding portion and a non-protruding portion. The protruding portion protrudes radially inward to include an abutting part that abuts the radially outer periphery of the stator core. The non-protruding portion extends, without protruding radially inward, to define a radial clearance between the radially outer periphery of the stator core and a radially inner surface of the non-protruding portion. The protruding and non-protruding portions are continuously formed in an axial direction of the outer cylinder.

Abstract: A stator includes an annular stator core that is comprised of a plurality of stator core segments, an outer ring that is fitted on the radially outer surfaces of the stator core segments so as to fasten them together, and a stator coil mounted on the stator core. Each of the stator core segments is formed of a plurality of stator core sheets that are laminated in the axial direction of the stator core. Each of the stator core sheets has a reinforcement portion that includes a recess formed in one of the major surfaces of the stator core sheet and a protrusion formed on the other major surface. The stator core sheets are laminated so that for each adjoining pair of the stator core sheets, the protrusion of one of the stator core sheets is fitted in the recess of the other stator core sheet.

Abstract: The present invention relates to a piercing apparatus and a piercing method which drive a punch. The piercing apparatus includes a local heating device for heating part of the workpiece in a temperature range less than a melting point of the workpiece and a punch driving device for driving the punch toward the part of the workpiece which was heated by the local heating device. The piercing method includes a local heating step for heating part of the workpiece in a temperature range less than a melting point of the workpiece and a stamping step for driving the punch toward the part of the workpiece which was heated in the local heating step.

Abstract: In a method of forming a hole on a work piece, a laser beam is directed from a laser head to a predetermined portion of the work piece to form a pilot hole having a first surface condition, and then the predetermined portion of the work piece is punched using a die and a punch having a cross-section greater than a cross-section of the pilot hole. Thus, a finished hole having a cross-section greater than the cross-section of the pilot hole is formed over the pilot hole. The finished hole has a second surface condition, and the second surface condition is formed by transforming the first surface condition by the punch to have a precise dimension.

Abstract: A stator includes an annular stator core that is comprised of a plurality of stator core segments, an outer ring that is fitted on the radially outer surfaces of the stator core segments so as to fasten them together, and a stator coil mounted on the stator core. Each of the stator core segments is formed of a plurality of stator core sheets that are laminated in the axial direction of the stator core. Each of the stator core sheets has a reinforcement portion that includes a recess formed in one of the major surfaces of the stator core sheet and a protrusion formed on the other major surface. The stator core sheets are laminated so that for each adjoining pair of the stator core sheets, the protrusion of one of the stator core sheets is fitted in the recess of the other stator core sheet.

Abstract: In a method of forming a hole on a work piece, a laser beam is directed from a laser head to a predetermined portion of the work piece to form a pilot hole having a first surface condition, and then the predetermined portion of the work piece is punched using a die and a punch having a cross-section greater than a cross-section of the pilot hole. Thus, a finished hole having a cross-section greater than the cross-section of the pilot hole is formed over the pilot hole. The finished hole has a second surface condition, and the second surface condition is formed by transforming the first surface condition by the punch to have a precise dimension.