PRODUCTION METHOD OF PISTON FOR COMPRESSOR

摘要

A method for producing a hollow piston for compressor by coupling a piston top side member and a rotation preventing portion side member where a rotation preventing portion and a cylindrical portion are formed integrally. When the rotation preventing portion side member is formed, an intermediate material for forging the rotation preventing portion side member is formed, the cylindrical portion of the rotation preventing portion side member is forged in a uniaxial direction by molding for pushing the cylindrical portion rearward in a punch inserting direction using a punch having a tip portion formed asymmetrically to a piston axis, and a material theft portion is formed to copy the asymmetric profile at the tip of the punch on the rotation preventing portion side bottom of the hollow section for forming the cylindrical portion. A hollow piston can be produced by simple and inexpensive forging and the position of the center of gravity can be brought closer to the axis of the cylindrical portion of the piston.