To provide a method of manufacturing an engine valve capable of reducing manufacturing manhours to suppress the manufacturing cost while increasing the heat transfer area of a hollow part formed in the valve.
A manufacturing process for manufacturing a valve shaft with forging includes a workpiece installation step S2, a workpiece insertion step S3, a vertical forging step S4, a horizontal forging step S5, a workpiece rotation step S6, and a workpiece axial movement step S8. After finishing first-stage forging in the vertical forging step S4 and the horizontal forging step S5, n-stage forging is performed in one cycle to machine a workpiece throughout its periphery while sequentially giving predetermined-angle-θ rotation to the workpiece in the workpiece rotation step S6 to change the pressure position.
OTA TAKAHIRO
ISHII KEN
NISHIO HIDENOBU
MORII HIROKAZU
SEKIMOTO YOSHIAKI
FUJITANI YASUYUKI
YOSHIMURA HYOJI
YOSHIMURA COMPANY KK
Kunio Ueda