| 摘要 |
PROBLEM TO BE SOLVED: To achieve both of the lightening of a rocker arm and the improvement of strength by forming the rocker arm out of a sheet of metallic plate having an uneven thickness, forming both side wall parts by a thin part of the metallic plate and forming connecting parts of both side wall parts by a thick part of the same. SOLUTION: A metallic plate having a thick part at its central part, and thin parts 26 at its both ends is stamped and shaped into a base plate 15a having a through hole 19 crossing over the thick part 25. Both side positionsαof the base plate 15a are bent at a right angle to form an intermediate material 27 having a pair of parallel side wall parts 11a. Then circular holes for supporting a roller supporting shaft are formed on longitudinal intermediate parts of both side wall parts at positions matched to each other, and a valve engagement hole is formed on one of connecting parts 17a, and a screw plate part or a pivot part is formed on the other connecting part 17b. That is, both side wall parts 11a free from heavy force is thinned, and both connecting parts 17a, 17b receiving heavy force, is thickened.
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