| 摘要 |
PROBLEM TO BE SOLVED: To provide a drilling method of a cylinder head which can reduce a chip amount remaining in an oil passage hole.SOLUTION: In a drilling process S100 for drilling a plurality of HLA holes 11A, ..., 11P which intersect with oil passage holes 12X and 12Y opened to the outside at one end sides and communicate therewith are formed at a cylinder head 100 in which the oil passage holes 12X and 12Y are formed by using rotating tools 15 and 16, the HLA holes 11A, ..., 11P are formed at positions in which axial lines of the oil passage holes 12X and 12Y are offset with the HLA holes 11A, ..., 11P, the rotating tools 15 and 16 are rotated so that rotational directions of the rotating tools 15 and 16 are oriented to on end sides of the oil passage holes 12X and 12Y at crossing parts between the oil passage holes 12X and 12Y and the HLA holes 11A, ..., 11P, and the drilling is sequentially performed from the HLA holes which are formed at the other end sides of the oil passage holes 12X and 12Y toward the HLA holes which are formed at one end sides of the oil passage holes 12X and 12Y.SELECTED DRAWING: Figure 1 |
