A robotic device may traverse a path in a direction of locomotion. Sensor data indicative of one or more physical features of the environment in the direction of locomotion may be received. The implementation may further involve determining that traversing the path involves traversing the one or more physical features of the environment. Based on the sensor data indicative of the one or more physical features of the environment in the direction of locomotion, a hydraulic pressure to supply to the one or more hydraulic actuators to traverse the one or more physical features of the environment may be predicted. Before traversing the one or more physical features of the environment, the hydraulic drive system may adjust pressure of supplied hydraulic fluid from the first pressure to the predicted hydraulic pressure.

A closed loop, self-priming hydraulic system comprising a reciprocating, hydraulic piston pump, a high pressure loop and a low pressure loop is disclosed. The reciprocating, hydraulic piston pump comprises a first piston operating in a first piston bore and a second piston operating in a second piston bore. The high pressure loop is defined by a high pressure accumulator that is fluidly connected to an inlet of the first piston bore and an outlet of the second piston bore. The low pressure loop is defined by a low pressure accumulator that is fluidly connected to an inlet of the second piston bore and an outlet of the first piston bore. The closed-loop, self-priming hydraulic system manipulates a hydraulic fluid to convert energy from one form to another.

In a method for operating a hydraulic device for providing a supply to hydraulic consumers (V) on a plastics injection moulding machine, provision is made of a pump (10) with a volumetric delivery characteristic that results in cyclic pulsations and of a servomotor (11) with multiple poles that result in cyclic pulsations. The pressure at the hydraulic consumer (V) is detected and is input as an actual value into a pressure regulator (13) that readjusts the servomotor (11), on the basis of a predefined pressure profile, to a pressure setpoint value at the hydraulic consumer (V). The cyclic pressure pulsation is minimized in that, by means of a rotational angle sensor (20), the rotational angle (φ) of the pump (10) and/or of the servomotor (11) is detected and correlated with the cyclic pulsations, and in that, from this, a corrective value or a corrective function is determined and is transmitted to the pressure regulator (13) with control subordinate to the regulation of the pressure setpoint value. Alternatively or in addition, this is achieved in the case of a hydraulic device also in that, as corrective means for the pressure regulation, said means being subordinate to the consideration of the pulsations, the number of components of the pump (10) that result in the cyclic pulsations and the number of components of the servomotor (11) that generate cyclic pulsations are equal, or one is a multiple of the other.

A ride control valve includes a valve housing (30) having a main spool (32) longitudinally displaceably arranged in the valve housing, a balance spool (34), and fluid passage points for a pressure supply (P), a tank return line (T), an accumulator (14) and a boom cylinder unit (10). The balance spool (34) continuously balances the pressure between the fluid ports of the accumulator (14) and the boom cylinder unit (10). The main spool (32) is controlled by the operator and initially interconnects these fluid ports of the accumulator (14) and the boom cylinder unit (10), starting from a closed fluid connection, via a restricted fluid connection, to a fully opened fluid connection, or disconnects them from each other in reverse sequence.

A device for reducing vibrations in a hydraulic system may have a separating device which has a side for delimiting a fluid-conducting cavity of the fluid system. The device may also have a vibration-reducing unit, which is designed to mechanically adjust the rigidity of the separating device such that vibrations in the fluid system are reduced.

A hydraulic flushing system comprises a hydraulic machine including a case drain, a gearbox having a cavity, and a flushing valve. The case drain is included in a hydraulic pump or a hydraulic motor. The flushing valve is fluidly connected to the case drain, fluidly connected to the cavity, and fluidly positioned between the case drain and the cavity. The flushing valve is configured to selectively allow hydraulic fluid to flow from the case drain to the cavity.

In hydraulic systems having rotating-stationary component interfaces, a bore pressure regulating mechanism is provided to interact with the hydraulic fluid in a control volume to maintain a hydraulic fluid pressure in a longitudinal shaft bore at or approximately equal to a supply pressure when a gear shaft rotates within the control volume. In one aspect, the bore pressure regulating mechanism minimizes vortex flow of the hydraulic fluid induced by the rotation of the gear shaft. In another aspect, the bore pressure regulating mechanism provides a direct feed of pressurized hydraulic fluid proximate an opening of the longitudinal shaft bore through an end surface of the gear shaft, and thereby minimizes the opportunity for the hydraulic fluid to be forced into vortex flow by the gear shaft in the area of the longitudinal shaft bore.

A mobile hydraulic system includes a hydraulic actuator coupled to a load, and a control unit coupled to the load and/or to the hydraulic actuator. The control unit is adapted to anticipate an over-center transition of the load relative to a gravity vector prior to the over-center transition through the use of sensors configured with accelerometers, gyroscopes and magnetometers. In some examples, the over-center transition is from an overrunning driving of the load to a passive driving of the load. In some examples, the over-center transition is from a passive driving of the load to an overrunning driving of the load. In some examples, the control unit is adapted to control change in a metered flow through one or more ports of the associated actuator to minimize and/or prevent one or more hydraulic effects of the anticipated over-center transition. In some examples, the control unit controls the metered flow by causing one or more actuators (e.g., a solenoid) to shift one or more valve positions to change the flow through one or more ports of the associated actuator.

The present invention relates to a hydraulic system with a feed pump for feeding hydraulic fluid, wherein the feed pump is driven by a hydraulic drive motor. The invention furthermore comprises a method for feeding hydraulic fluid into a hydraulic system via a feed pump, wherein the feed pump is driven by a hydraulic drive motor.

The present invention relates to a hydraulic system with a feed pump for feeding hydraulic fluid, wherein the feed pump is driven by a hydraulic drive motor. The invention furthermore comprises a method for feeding hydraulic fluid into a hydraulic system via a feed pump, wherein the feed pump is driven by a hydraulic drive motor.