Control mechanism for adjusting the displacement of an axial piston pump

摘要

The adjustment device includes a control valve (39) through which the control pipe (37) is connected to a high pressure pipe. A return coupling element (49) is mounted between the setting piston (30) and control valve (39) and the setting piston is displaced hydraulically controlled in dependence on the force difference arising between the control faces (33,35) so far until the force difference is zero. A swivel-out spring (47) is pretensioned by the setting piston shortly before reaching the zero position where the axial piston pump operates without or with only minimum delivery. The pretension of the spring (47) is such that it moves the setting piston when swivelling out from the zero position so far until the delivery pressure built up by the pump in the high pressure pipe is sufficient for hydraulically controlling the setting piston.