To freely rotate a camshaft to large angle using two driving tools alternately, by providing the camshaft with plural angle shaft parts with polygonal cross section such as hexagon such that phases for angle shaft parts are displaced mutually between any adjacent angle shaft parts.
Angle shaft parts 16, 17 with hexagonal cross section are provided for an intake valve camshaft 7 such that phases for angle shaft parts 16, 17 are displaced mutually, and angle shaft parts 18, 19 with hexagonal cross section are provided for an intake valve camshaft 8 such that phases for angle shaft parts 18, 19 are displaced mutually. In order to rotate the intake valve camshaft 7, first, a spanner A is engaged with the angle shaft part 16 and is rotated. Next, while the spanner A holds camshaft 7 to prevent a valve spring from returning the camshaft 7, another spanner B is engaged with the angle shaft part 17 and is rotated to rotate the camshaft 7 furthermore. By using spanners A, B mutually, the camshaft 7 can be rotated largely.
SHIBUYA SHIGENOBU
KAJIWARA YASUFUMI
MATSUSHITA TOSHIHIKO
KATSUTA KUNIHIKO
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