| 摘要 |
<p>PURPOSE:To always and stably obtain an appropriate valve closing characteristic of an intake or exhaust valve, irrespective of variation in the viscosity of hydraulic oil, the rotational speed of an engine or the like, by providing such an arrangement that the valve closing characteristic is given by cam profiles of a plurality of cams, independent from the damper action of hydraulic oil. CONSTITUTION:A valve drive device comprises a plurality of cams 3, 8 rotating with different phases, a plurality of cam plungers 4, 9 which reciprocate following the cams 3, 8, a hydraulic piston 1 which reciprocates in association with hydraulic pressure generated by the second cam plunger 9 during a first mode, and which reciprocates in association with hydraulic pressure generated by the first cam plunger 4 during a second mode during a second mode, and accumulators 10, 11 for accumulating hydraulic pressure generated by the cam plungers 4, 9. When the cam lift values of the cams 3, 8 are coincident with each other, the modes are changed over by a hydraulic selector valve 5. Meanwhile, an intake valve or an exhaust valve 12 is opened and closed following up the hydraulic piston 11.</p> |
