MANUFACTURING METHOD FOR ROCKER ARM

摘要

A manufacturing method for a rocker arm capable of stably forming valve stem guide walls. In the method, an intermediate product (13) having both side walls (20) extending in a predetermined direction and an end part connection wall (30) connecting the longitudinal one end parts of these both side walls (20) to each other is first manufactured. The areas of the outer surface parts of these both side walls (20) are plastically fluidized downward from cutout parts (31) in the outer surface parts of the both side walls by driving first pressing punches (70) therein from the outside to form rise walls (32) in a downwardly projected shape on both sides of the end part connection wall (30). Then, the both side rise walls (32) of the end part connection wall (30) are formed by driving second pressing punches (80) therein from the outside to form the valve stem guide walls (35).