The hole opening device of the sheet metal which possesses the punch and this punch for the hole opening of the sheet metal

摘要

The sheet metal of this invention (8) punch for the hole opening (13), punch itself (25) with, the center of the hypothetical circle where the periphery of the particular end face is inscribed to the end face of one side of this punch itself and being concentric, as projection of the gimlet condition which is provided in one body with the base which possesses the periphery which is inscribed to the hypothetical circle which possesses smaller diameter than diameter of particular hypothetical circle (28) with we possess, the shaft center which passes by the center of the hypothetical circle to which the periphery of the end face is inscribed and we cross hypothetical circle and the projection to which the periphery of the end face is inscribedThe angle which the tangential line and the end face which touch with to the advanced aspect form above the 25, is below the 60, with the radius D1/2 of the hypothetical circle to which the periphery of the end face is inscribed and of radius d1/2 of the hypothetical circle to which the periphery of the base is inscribed with ratio e/L of difference e and circumferential length L of the hypothetical circle to which the periphery of the end face is inscribed 0.05, or more is the value of 0.14 or less.