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摘要

PROBLEM TO BE SOLVED: To provide a boring method and a boring apparatus of a through-hole on the circumferential wall of a work by which the generation of burrs on the inner peripheral surface of a tubular part is prevented, the productivity is improved and the machining cost is remarkably reduced.;SOLUTION: This apparatus comprises a die 20 which is a mold for machining the circumferential wall 15 of the tubular part 12, a punch 30 the projected length of which is shorter than the thickness of the circumferential wall 15 on a rod-shaped metal core 32 held in a cantilever and inserted into the inside of the tubular part 12 and a pressurizing means 50 for boring the through-hole by generating shear and break by driving the punch 30 in the circumferential wall 15 from the inside of the tubular part 12 by relatively moving the punch 30 by pressurization in the proximity direction through the metal core 32. The metal core 32 is inserted into the holding hole 42 of an elevating and lowering block 40 for holding the metal core 32 in the rear end side where is the opposite side to the tip side on which the punch 30 is projected and provided and fixed attachably and detachably.;COPYRIGHT: (C)2006,JPO&NCIPI