| 摘要 |
A controllable hydraulic valve mechanism for reciprocating engines or pumps including a drive piston, operable by a cam is provided with control edges and projects into a drive cylinder; a working piston which operates the valve directly and is guided in a working cylinder. The valve mechanism provides a continuous communication between the drive cylinder interior and a second reservoir which absorbs a substantial part of the energy produced by the lift of a cam. Control sleeves surround the drive piston and are operable by actuating means operable from outside the drive cylinder. Each of the control sleeves has a control ring groove which cooperates with control edges provided in the drive piston. A further sleeve in the working cylinder surrounds the working piston, is rotatable by actuating means operable from outside the working cylinder, and is provided with a control ring groove for varying the valve lift. By means of this further sleeve, the working cylinder interior is connectable with a discharge conduit leading to the first reservoir. In this connection, the end face and the control ring groove are matched in such a way that a small amount of control fluid flows into the first reservoir during each valve lift adjustment. A cooler is provided in the refilling conduit. |
