| 摘要 |
A piston ( 6 ) of a piston pump unit ( 2 ), which can be displaced in a translatory manner, is guided in a cylinder bore ( 7 ). The piston ( 6 ) is driven by a crank drive ( 13 ) comprising an eccentric element ( 15 ) which is arranged on a drive shaft ( 14 ). A stroke ring ( 12 ) is rotationally mounted on the eccentric element ( 15 ) but does not rotate therewith. A sliding surface ( 10 ) of the piston ( 6 ) is arranged on a sliding bearing surface ( 11 ) on the stroke ring ( 12 ). A discharge chamber ( 22 ) is embodied inside the piston ( 6 ) on an end opposite the stroke ring ( 12 ). Said discharge chamber is open towards the sliding bearing surface ( 11 ). The discharge chamber ( 22 ) is connected in a pressure-wise manner to a working chamber ( 8 ) by means of a passage ( 23 ) in the piston ( 6 ). A displaceable control piston ( 25 ) is guided in a longitudinal bore ( 24 ) pertaining to said passage ( 23 ). Said control piston ( 25 ) is impinged upon on one side by a medium in the working chamber ( 8 ) and on the other front side by a pressure medium in the discharge chamber ( 22 ). The control piston ( 25 ) separates the medium which is to be transported from the pressure medium in the discharge chamber ( 22 ) and ensures that the pressure in the discharge chamber ( 22 ) increases if the pressure increases in the working chamber ( 8 ). This results in decompression of the sliding bearing between the piston ( 6 ) and the stroke ring ( 12 ).
|
