| 摘要 |
PROBLEM TO BE SOLVED: To facilitate the manufacture and to reduce the manufacturing cost, in the manufacturing method of a flow straightening member of internal combustion engine. SOLUTION: In the forging time of a cylinder head, a projection 8 projecting from the inner wall surface of a suction port 5 at the downstream side of the shaft 7b of a suction valve 7 provided in the suction port 5 is formed integral with the suction port 5, and then, at the boring processing time of a shaft part insertion hole 13 in order to insert a shaft 7b to the cylinder head, the upstream surface C1 of the projection 8 is cutting processed at the same time. And at the cutting processing time of a valve seat 24 abutting to the umbrella part 7a of the suction valve 7, the downstream surface C2 of the projection 8 is cutting processed at the same time, and the projection 8 is formed as a flow straightening member to straighten the suction air flow at the upstream side of the shaft 7b of the suction valve 7. |
