In general, certain embodiments of the present disclosure provide an electro-hydrostatic actuator comprising a piston assembly and a hydraulic cylinder. The piston assembly, having a piston head and a piston rod extending from the piston head, is located and movable within the hydraulic cylinder. The hydraulic cylinder includes a hydraulic fluid chamber region including a piston side chamber and a rod side chamber, a reservoir for storing hydraulic fluid located within the hydraulic cylinder which is in fluid communication with the hydraulic fluid chamber region. The electro-hydrostatic actuator includes a hydraulic pump system for moving hydraulic fluid in the reservoir and the hydraulic fluid chamber region, the hydraulic pump system in fluid communication with a flow control network in a hydraulic cylinder boss for controlling a direction and flow magnitude of hydraulic fluid within the hydraulic fluid chamber region, and an electric motor for driving the hydraulic pump system.

In general, certain embodiments of the present disclosure provide an electro-hydrostatic actuator comprising a piston assembly and a hydraulic cylinder. The piston assembly, having a piston head and a piston rod extending from the piston head, is located and movable within the hydraulic cylinder. The hydraulic cylinder includes a hydraulic fluid chamber region including a piston side chamber and a rod side chamber, a reservoir for storing hydraulic fluid located within the hydraulic cylinder which is in fluid communication with the hydraulic fluid chamber region. The electro-hydrostatic actuator includes a hydraulic pump system for moving hydraulic fluid in the reservoir and the hydraulic fluid chamber region, the hydraulic pump system in fluid communication with a flow control network in a hydraulic cylinder boss for controlling a direction and flow magnitude of hydraulic fluid within the hydraulic fluid chamber region, and an electric motor for driving the hydraulic pump system.

The invention relates to a device for supplying ports to a machine section (26) of a hydraulic machine arrangement (40), the device (10) comprising a low-pressure inlet port (12), a leakage inlet (16), a low-pressure chamber (18) having a low-pressure opening (22) for establishing fluid communication with the machine section (26), a high-pressure outlet port (14), and a high-pressure chamber (20) that is in fluid communication with the high-pressure outlet port (14), the high-pressure chamber (20) having a high-pressure opening (24) for establishing fluid communication with the machine section (26), wherein the low-pressure inlet port (12) is in fluid communication with the low-pressure chamber (18), wherein a leakage path (36) extends from the high-pressure chamber (20) through the machine section (26) to the leakage inlet (16), characterized in that the device (10) further comprises a control valve member (28) connecting the leakage inlet (16) to the low-pressure chamber (18), wherein the control valve member (28) transfers to an open state when a pressure in the leakage inlet (16) with respect to a pressure in the low-pressure chamber (18) is higher than a predefined control pressure threshold. The device (10) reduces cavitation in hydraulic machine arrangements (40).

A hydrostatic axial piston machine includes a pressing pressure chamber for the cylinder drum which is supplied with pressing pressure from a circular-arc-like elongate hole of a distributor plate or from a plurality of connection channels of the cylinder drum. The pressing pressure chamber is delimited radially outwardly by the cylinder drum and radially inwardly by the drive shaft. The pressing pressure chamber is delimited axially at both sides by seals which are both arranged between the radially inner rotating drive shaft and a radially outer stationary component. The radially outer component may be the cylinder drum or, in the case of the distributor-plate-side seal, also a gap seal between the drive shaft and a bearing bush of the distributor plate. Both seals are arranged at the distributor plate side with respect to a tooth arrangement or a retraction ball.

A hydrostatic axial piston machine includes a pressing pressure chamber for the cylinder drum which is supplied with pressing pressure from a circular-arc-like elongate hole of a distributor plate or from a plurality of connection channels of the cylinder drum. The pressing pressure chamber is delimited radially outwardly by the cylinder drum and radially inwardly by the drive shaft. The pressing pressure chamber is delimited axially at both sides by seals which are both arranged between the radially inner rotating drive shaft and a radially outer stationary component. The radially outer component may be the cylinder drum or, in the case of the distributor-plate-side seal, also a gap seal between the drive shaft and a bearing bush of the distributor plate. Both seals are arranged at the distributor plate side with respect to a tooth arrangement or a retraction ball.

There is disclosed a hydrostatic axial piston machine having a pulse reduction device. This device has a connection location or tap in the transition region in front of the high-pressure-side kidney-like elongate hole of a distributor plate. The connection location or tap is connected by means of one or two hydraulically passively controlled switching valves to a high-pressure store. It is used for precompression and consequently for the pulse reduction. In a development, the distributor plate also has a connection location or tap in the transition region behind the high-pressure-side kidney-like elongate hole. The connection location or tap is connected via one or two hydraulically passively controlled switching valves to a low-pressure store. This is used for the decompression and consequently also for the pulse reduction.

There is disclosed a hydrostatic axial piston machine having a pulse reduction device. This device has a connection location or tap in the transition region in front of the high-pressure-side kidney-like elongate hole of a distributor plate. The connection location or tap is connected by means of one or two hydraulically passively controlled switching valves to a high-pressure store. It is used for precompression and consequently for the pulse reduction. In a development, the distributor plate also has a connection location or tap in the transition region behind the high-pressure-side kidney-like elongate hole. The connection location or tap is connected via one or two hydraulically passively controlled switching valves to a low-pressure store. This is used for the decompression and consequently also for the pulse reduction.

A hydraulic axial piston machine (1) is described, the machine comprising a housing, a cylinder block (2) rotatably mounted in the housing about an axis or rotation (7) and having at least one cylinder (3), and a valve arrangement (4) between the cylinder block (2) and the housing, the valve arrangement having a first part (4) rotating with the cylinder block (2) and a second part mounted stationary with respect to the housing. Such a machine should have a high efficiency. To this end the first part (4) comprises an elastically deformable spring section (9).

A valve plate assembly (1) of a hydraulic axial piston machine is described, the valve plate assembly comprising a wear plate (2) made of a ceramic material surrounded by a compression ring (4). Such a valve plate assembly should be produced and maintained in a cost-effective manner. To this end, the wear plate (2) is connected to a support plate (3) by means of the compression ring (4).

A bent-axis axial-piston hydraulic machine may have a cylinder block being movable circumferentially about a first rotation axis. The machine may also have a transmission shaft which is functionally associated with the cylinder block and which can rotate about a transmission axis incident on the rotation axis. The machine may also have a distributor, and a device for angular offsetting which is associated with the distributor to rotate the distributor to cause a variation of effective cubic capacity while a geometric cubic capacity of the machine remains constant. The corresponding method for adjusting the capacity of a bent-axis axial piston hydraulic machine is also disclosed.