Method of and a device for forming a projection on a metal member and a metal part processed by the method of forming a projection

Abstract

The present invention provides a method of forming a solid projection having excellent mechanical properties on a metal member without supplying thermal energy from the outside, and a projection-forming device and a metal part having a projection manufactured thereby. The means for solving the problems is characterized in that the means is comprised of the processes of: pressing the distal end 13 a of the processing jig 13 having the hole-opening and a cavity 13 b at the distal end against the surface of the metal member workpiece 111 and rotating the metal member workpiece 111 and the processing jig 13 in the direction relatively counter to the other to generate friction heat causing thereby plastic flow into the cavity through the hole-opening 13 b.

What is claimed is: 
     
         1 . A projection-forming device comprised of:
 a holding means for holding a metal member workpiece;   a processing means having a hole-opening and a cavity at its distal end;   a means for rotating said processing means;   a means for moving at least one of said holding means and said processing means along the line that connects both said holding means and said processing means; and   a means for pressing said processing means against the surface of said metal member workpiece.   
     
     
         2 . A projection-forming device comprised of:
 a processing table to hold a metal member workpiece;   a rotary tool including a processing jig column having a distal end facing the processing table;   a rotary drive source to rotate the processing jig relative to the metal member workpiece; and   a vertical drive source to move one of the processing table or processing jig toward the other of the processing table or processing jig and initiate pressing contact with relative rotation between the distal end of the processing jig and the metal member workpiece, causing a plastic flow of metal from said metal member workpiece into a space between the processing jig column and a structure surrounding the processing jig column at the metal member workpiece surface on which the pressing contact was initiated.   
     
     
         3 . The projection-forming device of  claim 2 , wherein the plastic flow into the space is caused without the processing table being bonded to the workpiece by the pressing. 
     
     
         4 . The projection forming device of  claim 2 , further comprising a rotary tool that includes the structure and the processing jig column, wherein the space is a ring-like gap between the processing jig column and the structure at the metal member workpiece surface on which the pressing contact was initiated. 
     
     
         5 . A metal part having a projection formed integrally on a metal member, wherein the material of said projection is the same as the material of said metal member; and said projection and the surface region of said metal member near said projection are made to have a fine-grained structure compared with other region.