| 摘要 |
PROBLEM TO BE SOLVED: To provide the retaining device of a punch for hole-blanking of an automotive body with which service life of the punch is improved by eliminating shaking of the tip of a blanking punch for performing press working of a high-strength steel sheet (high-tensile material) having high tensile strength and high hardness. SOLUTION: This retaining device is composed of a backing plate 2 and a punch retainer 3 and is used for attaching the punch 4 for hole-blanking of the automotive body to the upper die holder 5 of an automotive pressing die. The high-tensile material (high-tensile steel sheet) of 0.5-1.5 mm thick is used for the automotive body and the retaining device is constituted so as to change the thickness of the backing plate 2 so that the pressure receiving area to the specific pressure applied to the upper die holder 5 via the backing plate 2 by impact force to the backing plate 2 which is generated by blanking force of the punch 4 when blanking the body with the punch 4 is extended in accordance with the magnitude of the blanking force of the punch 4 to the body. COPYRIGHT: (C)2007,JPO&INPIT
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