Patent ID: 9630232
Date: 2017-04-25
CPC Classifications: B21D

Claim:
1. A punch constituting, together with a die, a blanking die for punching a workpiece with a punching shape in which a plurality of protrusions protrude outwards from an annular body, wherein the punch includes a punch section including a cutting edge on a front end surface of the punch section, and a holder section for holding the punch section; the punch section is a cylinder in which a shape of the front end surface corresponding to the punching shape of the workpiece is continuous to a rear end surface; the holder section is a short cylinder including an inner circumferential surface formed in correspondence with an outer circumferential surface of the punch section to allow insertion of a rear part of the punch section; tops of protrusions of the punch section are brought into intimate contact with recesses of the holder section, and a clearance is provided between part of the punch section other than the protrusions and part of the holder section other than the recesses so that an adhesive is injected into the clearance to fix the punch section in the holder section; the protrusions of the punch section and the recesses of the holder section are each arc-shaped; and the radius of each of the recesses of the holder section is longer than the radius of each of the protrusions of the punch section, and the adhesive is injected into a clearance formed on a lower end part between the recesses of the holder section and the protrusions of the punch section.