Metal container and manufacturing method for same

Abstract

Provided are a metal container and a method for manufacturing same. The metal container includes an opening portion, a sidewall portion, and a bottom portion and has a lower end outer diameter smaller than an upper end inner diameter. The metal container has a shape of a bottomed cup formed by drawing a plate-like metal material and subjected to trimming, the sidewall portion has a tapered profile formed by performing diameter reduction drawing on the bottom portion side with respect to the opening portion of the bottomed cup, and the sidewall portion is formed with a bulging portion bulging in a circumferential direction and a continuous tapered surface where tapered surfaces are formed in a continuous manner by performing diameter reduction drawing a plurality of times on a lower side with respect to the bulging portion.

1 . A metal container comprising:
 an opening portion;   a sidewall portion; and   a bottom portion,   the metal container having a lower end outer diameter smaller than an upper end inner diameter,   wherein the metal container has a shape of a bottomed cup formed by drawing a plate-like metal material and subjected to trimming,   the sidewall portion having a tapered profile is formed by performing diameter reduction drawing on the bottom portion side with respect to the opening portion of the bottomed cup, and   the sidewall portion is formed with a bulging portion bulging in a circumferential direction and a continuous tapered surface where tapered surfaces are formed in a continuous manner by performing diameter reduction drawing a plurality of times on a lower side with respect to the bulging portion.   
     
     
         2 . A method for manufacturing a metal container including an opening portion, a sidewall portion, and a bottom portion and having a lower end outer diameter smaller than an upper end inner diameter, the method comprising:
 forming a bottomed cup by drawing a plate-like metal material;   trimming the bottomed cup; and   forming the sidewall portion having a tapered profile by performing diameter reduction drawing on the bottom portion side with respect to the opening portion of the bottomed cup,   wherein in the forming the sidewall portion, a bulging portion bulging in a circumferential direction is formed, and a continuous tapered surface where tapered surfaces are formed in a continuous manner is formed by performing diameter reduction drawing a plurality of times on a lower side with respect to the bulging portion.   
     
     
         3 . The method for manufacturing a metal container according to  claim 2 ,
 wherein assuming that a vertical height H from a ground contact portion to an upper end of the metal container is 100%, the continuous tapered surface has a vertical height H 1  of at least from 20 to 30% with respect to the vertical height H.   
     
     
         4 . The method for manufacturing a metal container according to  claim 2 , comprising:
 forming the opening portion including a curl or a flange.   
     
     
         5 . The method for manufacturing a metal container according to  claim 2 ,
 wherein a ratio of an upper end inner diameter to a lower end outer diameter of the metal container is from 1.2:1 to 2:1.   
     
     
         6 . The method for manufacturing a metal container according to  claim 2 ,
 wherein the tapered surface and the continuous tapered surface are formed by diameter reduction drawing using an outer tool including a curved surface, and the curved surface of the outer tool for forming the continuous tapered surface has a larger radius of curvature than a radius of curvature of the curved surface of the outer tool for forming the tapered surface.