| 摘要 |
<p>PURPOSE:To prevent unstable operation of a valve by opening a control valve in the case where pressure is short at the time of starting, in relation to a hydraulic valve driving device. CONSTITUTION:An oil pressure pump 20 is constituted as a variable capacity type, and provided with a means capable of varying capacity such as a swash plate angle or the like. And the angle of the swash plate is controlled by a control circuit 61 so as to obtain an objective oil pressure value according to an engine rotational speed. A hydraulic valve driving device is provided with a high pressure side control valve 32 used for leading and controlling operating oil from the oil pressure pump 20 into oil pressure chambers 16, 16', and a low pressure side control valve 42 used for discharging and controlling operating oil discharged from the oil pressure chambers 16, 16'. When intake valves 10, 10' are lifted, the high pressure side cntrol valve 32 is opened, and the low pressure side control valve 42 is closed so as to control the lift amount of the intake valves 10, 10' by the opening time of the high pressure side control valve 32. In the case where pressure in the oil pressure pump 10 is short at the time of starting, the high pressure side control valve 32 is closed, and the low pressure control valve 42 is opened. And oil pressure from the oil pressure chambers 16, 16' is discharged toward an oil tank 24 side so as to maintain the intake valves 10, 10' in closing condition.</p> |
