Hydraulic drive for movement control of incrementally variable camshaft adjustment - adjusts relative rotary angle between camshaft and drive wheel and uses pump and valve arrangement

摘要

The pump and valve arrangement is activated via the control chambers of the camshaft dependent upon positioning signals. A valve-controlled piston-pump system (22-28, 60, 54, 56) is provided with an impeller pump arrangement (22,26,24,28) for each control chamber, with which the corresp. suction valves (54,56) of the impeller-pump arrangements (22,26,24,28) are controllable selectively individually or in common by means of a positioning mechanism (60) working against a rear position. The activation of the control chambers (12,14) is achieved by unblockable check valves (34,36), which are unblocked by the system pressure in the supply line in the other control chamber as soon as that pressure exceeds a threshold valve. USE/ADVANTAGE - A hydraulic drive for incrementally variable camshaft adjustment which is compact in formation, provides high dynamics and a reduced power loss in the rest condition.