PURPOSE: To precisely and easily execute forming work of a small hole opened to a cylinder hole in a hydraulic working device for vehicle.
CONSTITUTION: Protrusions 3d are arranged so as to be pushed out/pulled in cores 3, 3 for forming the cylinder holes 2, 2 and molten metal is poured into cavities wherein the pushed out protrusions 3d, 3d in the cores 3, 3 facing the each other are arranged, and after the molten metal is solidified, the cores 3, 3 incorporating the protrusions 3d, 3d are pulled out, thus, at the same time that the casting formation of the cylinder holes 2, 2 is executed, recessed parts 2a, 2a are formed on inner walls of the cylinder holes 2, 2. Pressure liquid introducing hole is bored from outside a caliper 1 to open the holes in the recessed parts 2a, 2a, and then, the recessed parts 2a, 2a are communicated through the pressure liquid introducing hole to form a communicating hole in between the cylinder holes 2, 2.
| JPH11320030 | JACKET CORE FOR FORMING CYLINDER BLOCK |
| JPS63203263 | LIGHT METAL ALLOY CASTING |
OTSUKA FUMIO
SEKI YUKIO
