Patent ID: 7585158

Claim:
Piston machine comprising a rotatably mounted cylindrical drum ( 2 ), disposed in which is a plurality of cylindrical bores ( 3 , 4 ), which are distributed over the circumference and in which displaceable pistons ( 5 , 6 ) are disposed, wherein the cylindrical bores ( 3 , 4 ) at one side have cylindrical openings ( 7 , 8 , 35 . 1 , 35 . 2 , . . . 35 . 9 ), which in accordance with the angle of rotation of the cylindrical drum ( 2 ) are temporarily in communication in each case with one of two outlet-side kidney-shaped control ports ( 9 , 10 ), which are connected in each case to an outlet-side working line ( 27 , 28 ), wherein between the kidney-shaped control ports ( 9 , 10 ) there is formed, in each case, a switchover region ( 30 , 31 ) and wherein a first end ( 32 ) of a pressure compensation line ( 33 ) opens out at least into one switchover region ( 30 , 31 ), wherein a second end ( 34 ) of the pressure compensation line ( 33 ) opens into the outlet-side working line ( 27 ), wherein the length (L) of the outlet-side working line ( 27 ) between the one said outlet-side kidney-shaped control port ( 9 ) and the second end ( 34 ) of the pressure compensation line ( 33 ), in the case of a hydraulic pump, is so dimensioned that the advancing pressure wave in the working line ( 27 ) at the moment at which a pressure maximum reigns at the second end of the pressure compensation line, the first end ( 32 ) in the switchover region ( 30 ) comes into contact with a further cylindrical opening and a pressure medium flows from the working line over the pressure compensation line into the further cylindrical opening, and/or that the length in the case of a hydraulic motor is so dimensioned that the instant, when the further cylindrical opening ( 35 . 1 ) comes into contact with the opening at the first end ( 32 ) of the pressure compensation line ( 33 ), a pressure minimum prevails at the second end ( 34 ) of the pressure compensation line ( 33 ), wherein at the moment at which the first end in the switchover region comes into contact with said further cylindrical opening, the cylindrical opening has no direct contact with the outlet-side kidney-shaped control port.