| 摘要 |
<p>PURPOSE:To eliminate the need for a large size actuator, enable to settle the problems such as power loss, wear of levers and the like, and at the same time improve the transient responsiveness of control by a method wherein the inclination of each lever is respectively controlled by a hydraulic actuator, the extension and contraction of which is controlled in response to the rotated position of a control sleeve. CONSTITUTION:The effective length of a hydraulic actuator 25 is elongated by overlapping the oil pressure feeding port 37 of a control sleeve 28 with the oil hole 36 of an outer cylinder 29 due to the rotation of the control sleeve 28 driven by a control rack 26, resulting in rocking a lever 20 counterclockwise by pushing downward in order to bring the back face of a rocker arm 17 and the face 21, to which the rocker arm 17 is supported, of the lever 20 in closely contact state. Accordingly, suction and exhaust valves 12 are open and closed in the nearly same timing with the increasing and decreasing displacements of a valve driving cam 11 and at the same time the maximum valve lifts also become larger. The hydraulic actuator 25 is employed on each lever 20 in such a manner as mentioned above, resulting in enabling to quick control the inclination of each lever during the period, in which no reaction of a valve spring is applied to the lever 20.</p> |
