| 摘要 |
PROBLEM TO BE SOLVED: To provide a rack bar manufacturing method that suppresses entrainment of a material during flat crushing and prevent the forged surface remaining after the polishing of a rack bar, thereby lengthening a sliding part or a sealing part after being incorporated in a steering device or the like, enhancing the quality surplus of steering performance by enhancing the flexibility of product arrangement, and also securing a stable steering capability by preventing an oil leak in a hydraulic steering system.SOLUTION: A rack bar manufacturing method includes: a step of fixing a cylindrical shaft part 11; a step of forming a flatly-crushed part 12 having lengths L1, L2 in an axial direction at a portion of an outer circumferential surface of a shaft part 11, having a width H in the direction perpendicular to the axial direction, and having a flat shape in which the length L1 in the vicinity of a central part in the width H direction is formed shorter than the length L2 in the vicinity of both ends in the width H direction; a step of fixing a tooth die having a rack teeth transfer part S1 for transferring rack teeth, while the rack teeth transfer part S1 comes into contact with the flatly-crushed part 12; and a step of forming the rack teeth by transferring the rack teeth transfer part S1 to the flatly-crushed part 12. |
