| 摘要 |
PROBLEM TO BE SOLVED: To improve measure accuracy of an injection hole by forming the injection hole by blanking, and providing an inlet edge of the injection hole with grinding machining. SOLUTION: Before brushing machining, an blanked inlet edge 3d of an injection hole 3c machined by blanking becomes in a die wear shape. By grinding it with a front side rotation brush 34, one side portion in a long circle direction of the inlet edge 3d of the injection hole 3c is in the die wear shape. Then, by grinding it with a rear side rotation brush 34, the other side portion in the long circle direction of the inlet edge 3d of the injection hole 3c becomes in the die wear shape. At this time, when the rear side rotation brush 34 rotates oppositely to the front side rotation brush 34, the left side portion of the inlet edge 3d of the left and right injection holes 3c is grinding machined, and thereby the die wear shape of the same portion 3c expands. Thus, the die wear shape of the inlet edge 3d of the left and right injection holes 3c is expanded in a right and left symmetric shape to finish flow adjustment.
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