| 摘要 |
<p>PROBLEM TO BE SOLVED: To downsize a four cycle engine, light a weight, reduce engine vibration caused at the time of acceleration or deceleration, reduce twist vibration of a cam shaft so as to stabilize opening/closing driving of an intake valve and an exhaust valve, and exhibit an engine output. SOLUTION: In this four cycle engine provided with the cam shaft 50 interlocked with a crank shaft 36, a valve driving means B which includes a cam 96 formed on the cam shaft 50, and for driving the intake valve and the exhaust valve 66, and for opening/closing the intake valve and the exhaust valve once every when the cam shaft is rotated once, and an output shaft 59 from an engine body 10, a driving gear 52 is arranged on the crank shaft 36, a driven gear 51 is disposed on the cam shaft 50, whose gear number is twice of the driving gear 52, and a turning force output part 50a to the output shaft 59 is disposed on the cam shaft 50. In the cam shaft 50, the cam 96 is disposed on one side serving an arranging position of the driven gear 51 as a boundary, and the turning force output part 50a is disposed on the other side.</p> |
