| 摘要 |
PROBLEM TO BE SOLVED: To provide a forward and reverse switching device of a four-cycle engine capable of switching the direction of a crankshaft of an engine between forward and reverse directions. SOLUTION: In the forward and reverse switching device of a four-cycle engine, an intake port and an exhaust port are formed in a cylinder head 6 so as to open to a combustion chamber 7. The intake port is opened and closed by an intake valve. The exhaust port is opened and closed by an exhaust valve. A valve system cam 21 for the intake valve and a valve system cam 22 for the exhaust valve are fitted to a camshaft 17 freely rotatably provided to the cylinder head 6 so as to freely switch and move between a normal rotating direction and a reverse rotating direction with respect to the camshaft 17. A shifter rod 24 is fitted into a hollow hole 23 formed in the camshaft 17 so as to be freely slidable in an axial direction. The cam grooves 33, 34 engaged with engagement pins 31, 32 fixed to the valve system cams 21, 22 are formed in a shifter rod 24. The phases of valve system cams 21, 22 are switched between normal rotation and reverse rotation. COPYRIGHT: (C)2005,JPO&NCIPI
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