A system for detecting an abnormality in hydraulic rotating equipment according to one embodiment includes: a sensor that measures a drain pressure of the hydraulic rotating equipment; and processing circuitry. The hydraulic rotating equipment is of an axial piston type and includes M pistons. The processing circuitry performs frequency analysis on a pressure waveform that is a result of measurement by the sensor to generate a frequency spectrum, and if a pressure amplitude of a rotational Mth-degree component in the frequency spectrum is less than a predetermined percentage of a pressure amplitude of a rotational first-degree component in the frequency spectrum, determines that the hydraulic rotating equipment is in a normal condition, whereas if the pressure amplitude of the rotational Mth-degree component is greater than the predetermined percentage of the pressure amplitude of the rotational first-degree component, determines that there is an abnormality in the hydraulic rotating equipment.

A system for detecting an abnormality in hydraulic rotating equipment according to one embodiment includes: a sensor that measures a drain pressure of the hydraulic rotating equipment; and processing circuitry. The hydraulic rotating equipment is of an axial piston type and includes M pistons. The processing circuitry performs frequency analysis on a pressure waveform that is a result of measurement by the sensor to generate a frequency spectrum, and if a pressure amplitude of a rotational Mth-degree component in the frequency spectrum is less than a predetermined percentage of a pressure amplitude of a rotational first-degree component in the frequency spectrum, determines that the hydraulic rotating equipment is in a normal condition, whereas if the pressure amplitude of the rotational Mth-degree component is greater than the predetermined percentage of the pressure amplitude of the rotational first-degree component, determines that there is an abnormality in the hydraulic rotating equipment.

A hydrostatic positive displacement machine (1) with a variable displacement volume includes a cradle (3) pivoted by a hydraulic positioning device (7) having a positioning piston device (8). A position-controlled control valve (10) generates a control pressure and includes axially displaceable and locked setting valve means (20) and the rotatable feedback valve means (21). Control cross sections are exposed by an axial displacement of the setting valve means (20) relative to the feedback valve means (21) and are closed by rotational movement of the feedback valve means (21) relative to the setting valve means (20).

A hydraulic device comprises a housing and a shaft with a flange extending perpendicularly to a first axis of rotation. A plurality of pistons are fixed to the flange and move each in a sleeve supported by and rotatable with a barrel plate. The barrel plate is provided with a plurality of actuators for exerting counter forces (Fa) on the respective sleeves in a direction and at a location such that at least when one of the pistons is at bottom dead center under operating conditions the counter force on the cooperating sleeve acts along a line at a distance from the center point of the piston head and causes a counter torque about the center point of the piston head against the tilting torque, wherein the actuators are controlled such that the counter forces increase with increasing rotational speed of the barrel plate about the second axis of rotation.

A hydraulic device comprises a housing and a shaft with a flange extending perpendicularly to a first axis of rotation. A plurality of pistons are fixed to the flange and move each in a sleeve supported by and rotatable with a barrel plate. The barrel plate is provided with a plurality of actuators for exerting counter forces (Fa) on the respective sleeves in a direction and at a location such that at least when one of the pistons is at bottom dead center under operating conditions the counter force on the cooperating sleeve acts along a line at a distance from the center point of the piston head and causes a counter torque about the center point of the piston head against the tilting torque, wherein the actuators are controlled such that the counter forces increase with increasing rotational speed of the barrel plate about the second axis of rotation.

A hydraulic device comprises a housing and a shaft with a flange extending perpendicularly to a first axis of rotation. A plurality of pistons are fixed to the flange and move each in a sleeve supported by and rotatable with a barrel plate. The barrel plate is provided with a plurality of actuators for exerting counter forces (Fa) on the respective sleeves in a direction and at a location such that at least when one of the pistons is at bottom dead center under operating conditions the counter force on the cooperating sleeve acts along a line at a distance from the center point of the piston head and causes a counter torque about the center point of the piston head against the tilting torque, wherein the actuators are controlled such that the counter forces increase with increasing rotational speed of the barrel plate about the second axis of rotation.

A hydraulic device comprises a housing and a shaft with a flange extending perpendicularly to a first axis of rotation. A plurality of pistons are fixed to the flange and move each in a sleeve supported by and rotatable with a barrel plate. The barrel plate is provided with a plurality of actuators for exerting counter forces (Fa) on the respective sleeves in a direction and at a location such that at least when one of the pistons is at bottom dead center under operating conditions the counter force on the cooperating sleeve acts along a line at a distance from the center point of the piston head and causes a counter torque about the center point of the piston head against the tilting torque, wherein the actuators are controlled such that the counter forces increase with increasing rotational speed of the barrel plate about the second axis of rotation.