Press die assembly

Abstract

A press die assembly includes a lower die, an upper die, a stripper plate provided between the lower die and the upper die, and a coupling member that couples the upper die and the stripper plate to each other such that the upper die and the stripper plate are movable relative to each other. The upper die includes a punch, an upper die main body, and an elastic member. The punch includes a first large-diameter portion and a second large-diameter portion. The upper die main body includes a restricting portion that restricts downward movement of the punch by contacting the second large-diameter portion. The elastic member is configured to urge the punch toward the restricting portion and to allow the upper die main body to approach the punch by being compressively deformed in a state in which the first large-diameter portion is in contact with the stripper plate.

What is claimed is: 
     
         1 . A press die assembly configured to perform press working on a workpiece, comprising:
 a lower die including a die hole;   an upper die configured to be moved in a vertical direction toward and away from the lower die;   a stripper plate that is provided between the lower die and the upper die and is configured such that the workpiece is held between the stripper plate and the lower die; and   a coupling member that couples the upper die and the stripper plate to each other such that the upper die and the stripper plate are movable in a vertical direction relative to each other, wherein   the upper die includes:
 a punch; 
 an upper die main body that accommodates an upper end portion of the punch; and 
 an elastic member provided between the upper end portion of the punch and a portion of the upper die main body that is located above the upper end portion, 
   the punch includes:
 a first large-diameter portion that restricts the punch from pressing into the workpiece by contacting the stripper plate; and 
 a second large-diameter portion that is located above the first large-diameter portion and has a diameter larger than that of the first large-diameter portion, 
   the upper die main body includes a restricting portion that restricts the punch from moving downward by contacting the second large-diameter portion, and   the elastic member is configured to urge the punch toward the restricting portion and to allow the upper die main body to approach the punch by being compressively deformed in a state in which the first large-diameter portion is in contact with the stripper plate.   
     
     
         2 . The press die assembly according to  claim 1 , wherein the punch includes:
 a tubular support member including the first large-diameter portion at a lower end and the second large-diameter portion at an upper end; and   a punch main body that includes:
 a main body portion that is inserted through the support member and protrudes further downward than the first large-diameter portion; and 
 a flange portion that is provided at an upper end of the main body portion and abuts an upper surface of the support member. 
   
     
     
         3 . The press die assembly according to  claim 1 , wherein
 the press die assembly is employed in an apparatus for manufacturing a motor core formed by stacking multiple iron core pieces, and   the press die assembly is configured to use the punch to form, in each of the iron core pieces, a tab that bulges to one side in a stacking direction of the iron core pieces, the tabs being used to couple the iron core pieces adjacent to each other.