| 摘要 |
PURPOSE:To surely perform the positioning in the peripheral direction by a small bore hole piercing by driving a piercing punch in the radial direction of a bottomed hole after deciding the position in the peripheral direction by fitting the guide pin of an insertion body with the positioning hole of a work. CONSTITUTION:A work (master cylinder of a brake device) 1 is held by a supporting frame 38 and clamping unit. The work 1 is clamped by moving the pressure part of the clamping unit to the pushing-in body side by inserting a insertion body 37 into the work 1. The positioning in the axial direction is thus performed together with an annular abutting member 49. The tip part 95 of the guide 90 supported with floating by the flange part 55 of the insertion body 37 is fitted with the receiving face 36 provided on the flange 32 of the work 1 to decide the relative position in the peripheral direction. After piercing large bore holes 29, 31 small bore holes 28, 30 are pierced by projecting each piercing punch 56, 57 to the wall part side of the work 1 by moving a cam slider 73 to the tip. In this way, the breakdown of the piercing punch can be prevented and the positioning in the peripheral direction can be ensured.
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