Abstract: Each cylinder of a hydrostatic hydraulic machine of the displacement type is preliminarily pressurized after the inlet port of the cylinder has been exposed to the low pressure side of the machine and before the inlet port of the cylinder is exposed to the high pressure side of the machine. The preliminary pressurization is effected by use of a separate pressure chamber containing a pressurized fluid that is rapidly discharged into the inlet port of each cylinder before the cylinder inlet port is exposed to the high pressure side of the machine. The separate pressure chamber is recharged from the high pressure side of the machine at a rate that is slower than the rate at which pressurized fluid is discharged from the chamber into the inlet port of a cylinder.

Abstract: A variable displacement hydrostatic axial piston machine has a cylinder barrel which is rotatable in a yoke and has a plurality of circumferentially spaced cylinder bores in which are mounted pistons which with the ends of their associated piston rods are journalled in a drive disk on a machine shaft rotatably mounted in the casing of the machine. The yoke is mounted in said casing pivotable about a transfer axis through the drive disk center by means of an adjustment device for varying the displacement and possibly also the mode of the operation of the machine, in the yoke and the machine casing furthermore being disposed a pair of hydraulic fluid connecting conduits.