| 摘要 |
PURPOSE:To provide a variable valve timing mechanism which is that of a four-cycle internal combustion engine having a DOHC mechanism and which is excellent in high speed rotational performance and which also has the mechanism reliability higher than that of the conventional one. CONSTITUTION:Two rocker-arms 4 for low speed and one rocker-arm 7 for high speed are arranged for two intake/exhaust valves 19. Next, a shaft 16 for connection/separation which interlocks or independently operates three rocker-arms is built in a rocker-arm shaft 9. Further, parts which are called as connecting bodies 10, 11 are passed from the rocker-arm surface to the center axis of the shaft, and the shaft 16 for the connection/separation is slid inside the rocker-arm shaft 9. As a result, the opening/closing timings of the intake/ exhaust valves 19 are switched in two stages for low and high speed by means of interaction between two kinds of slits set on the surface of the shaft 16 for the connection/separation and the connecting bodies 10, 11.
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