Forging apparatus and forging method

Abstract

The forging apparatus includes: a fixed punch 21 in which a tapered part 21a for molding the diameter enlarged part is formed; a die 30 arranged so as to surround an outer periphery of the fixed punch 21; and a movable punch 10 that is arranged above the fixed punch 21 so as to be opposed to the fixed punch 21. The die 30 is floatingly supported and includes a protruding part 33a for molding the groove on an inner peripheral surface thereof, and when the movable punch 10 is lowered, an annular blank 40 set between the fixed punch 21 and the die 30 is pressed, and the annular member is molded, the die 30 is lowered along with the movable punch 10, and the groove is molded on the outer peripheral surface of the diameter enlarged part while molding the diameter enlarged part.

What is claimed is: 
     
         1 . A forging apparatus for molding an annular member having an outer peripheral surface of a diameter enlarged part where a groove is formed, an inner diameter of the diameter enlarged part being gradually enlarged toward one end, the forging apparatus comprising:
 a fixed punch in which a tapered part for molding the diameter enlarged part is formed;   a die arranged so as to surround an outer periphery of the fixed punch; and   a movable punch that is arranged above the fixed punch so as to be opposed to the fixed punch, wherein   the die is floatingly supported and includes a protruding part for molding the groove on an inner peripheral surface thereof, and   when the movable punch is lowered, an annular blank set between the fixed punch and the die is pressed, and the annular member is molded, the die is lowered along with the movable punch, and the groove is molded on the outer peripheral surface of the diameter enlarged part while molding the diameter enlarged part.   
     
     
         2 . The forging apparatus according to  claim 1 , wherein a recessed part is provided on a lower surface of the movable punch, and when the movable punch is lowered, an end part of the fixed punch is fitted into the recessed part. 
     
     
         3 . A forging method for molding an annular member having an outer peripheral surface of a diameter enlarged part where a groove is formed, an inner diameter of the diameter enlarged part being gradually enlarged toward one end, the method comprising:
 setting an annular blank between a fixed punch where a tapered part for molding the diameter enlarged part is formed and a die arranged so as to surround an outer periphery of the fixed punch; and   molding the annular member by lowering a movable punch that is arranged above the fixed punch so as to be opposed to the fixed punch and pressing the blank, wherein   the die is floatingly supported and includes a protruding part for molding the groove on an inner peripheral surface thereof, and   in molding of the annular member, the die is lowered along with the movable punch, and the groove is molded on the outer peripheral surface of the diameter enlarged part while molding the diameter enlarged part.   
     
     
         4 . The forging method according to  claim 3 , wherein a recessed part is provided on a lower surface of the movable punch, and when the movable punch is lowered, an end part of the fixed punch is fitted into the recessed part.