| 摘要 |
<p>In a manufacturing method of a rack shaft, the rack shaft is formed by mounting a shaft raw material (A) on a receiving groove (21) of a lower mold (2), the receiving mold having an approximately U-shaped cross section, thereafter arranging an upper mold (4) having a rack-teeth-forming teeth portion (41a) formed in a rectangular shape in a bottom view and capable of oscillating in a width direction of the receiving groove (21) around a center in the width direction of the rack-teeth-forming teeth portion (41a), in such a manner that the center of oscillation lies on a vertical line of a center in a width direction of the rack teeth, pressing the shaft raw material (A) in the diametrical direction, deforming the shaft raw material (A) along the receiving groove (21), and thereafter deforming the shaft raw material (A) while oscillating the upper mold (4) so as to form a rack teeth.</p> |
