| 摘要 |
PURPOSE:To work a compensating hole without generating a chip and a burr by inserting a punch arbor and a punch rod which has formed an inclination partially, into a center hydraulic pressure chamber of a master cylinder, and executing a punching. CONSTITUTION:A master cylinder base material 8 is fixed to a jig of a work fixing part, a punch arbor 1 of a punching part is inserted into a hole 8C of the base material 8, and a stepped part 1a is advanced to a position of the jig. When a punch rod 2 moves an inner hole 1b of the punch arbor 1 in the right direction, a punch holder 3 moves in the straight direction along an inclination of a slant face part 10, and a punch 4 of the tip of the punch holder 3 works a wall 8c which a compensating hole 8a does not pass through. In this way, the compensating hole 8a is made to pass through in a state that a burr, a chip, etc. have been generated in only a reservoir side. |
