A reservoir for a hydraulic system has a housing with an interior space and a fluid outlet, a hydraulic driving device coupled to a shaft extending in the housing to introduce a torque, and a separating device in the housing, for dividing the interior space into two separate sections. The fluid outlet is fluidically connected to a first section. The separating device extends along the shaft in the housing and sets the size ratio of the two separate sections by pivoting at least one first surface, coupled to the shaft, of the separating device about an axis defined by the shaft. The separating device is coupled to the hydraulic driving device such that the at least one first surface exerts a pressure on a fluid in the first section which is dependent on a surface area of the first surface and the torque.

An example valve includes: (i) a valve body defining a longitudinal cavity, where the valve body includes a supply inlet and an operating outlet; (ii) a cage disposed in the longitudinal cavity, where the cage includes (a) a first opening fluidly coupled to the supply outlet, and (b) a second opening fluidly coupled to the operating outlet; and (iii) a spool mounted within the cage and configured to move axially therein. When the valve is actuated, the spool moves within the cage to form a gap, thereby allowing pressurized fluid to flow from the supply inlet through the first opening, the gap, and the second opening to the operating outlet. A flow area defined around an exterior peripheral surface of the spool changes upstream from the gap at a first rate, and changes downstream from the gap at a second rate that is different from the first rate.

An actuator is connected to a frame and a boom arm to pivot the boom arm with respect to the frame. A spool valve directs fluid from a pump into a selected side of the actuator. A first anti-cavitation valve is fluidly positioned between the first end of the actuator and the reservoir to permit fluid flow from the reservoir to the first end of the actuator while the first anti-cavitation valve is open and inhibit fluid flow from the first end of the actuator to the reservoir. A second anti-cavitation valve is fluidly positioned between the second end of the actuator and the reservoir to permit fluid flow from the reservoir to the second end of the actuator while the second anti-cavitation valve is open and inhibit fluid flow from the second end of the actuator to the reservoir.

A vortex reservoir for separation of an aerated portion of a hydraulic fluid includes an upper chamber and a lower chamber, in fluid communication with the upper chamber, having a lower chamber sidewall. The lower chamber includes a lower lower chamber and an upper lower chamber. The lower chamber includes a lower chamber partitioning plate. The lower chamber partitioning plate is located between the lower lower chamber and the upper lower chamber. The lower lower chamber is in fluid communication with the upper lower chamber via a gap between the lower chamber partitioning plate and the lower chamber sidewall.

A vortex reservoir for separation of an aerated portion of a hydraulic fluid includes an upper chamber and a lower chamber, in fluid communication with the upper chamber, having a lower chamber sidewall. The lower chamber includes a lower lower chamber and an upper lower chamber. The lower chamber includes a lower chamber partitioning plate. The lower chamber partitioning plate is located between the lower lower chamber and the upper lower chamber. The lower lower chamber is in fluid communication with the upper lower chamber via a gap between the lower chamber partitioning plate and the lower chamber sidewall.

Disclosed embodiments include travel motor hydraulic circuits for controlling the provision of hydraulic fluid to a travel motor. The travel motor hydraulic circuits include a counterbalance valve configured to block the flow of hydraulic fluid when in a neutral position to prevent unintended movement of a power machine, and an anti-cavitation valve configured to direct flow of hydraulic fluid back to the travel motor to prevent cavitation.

Disclosed embodiments include travel motor hydraulic circuits for controlling the provision of hydraulic fluid to a travel motor. The travel motor hydraulic circuits include a counterbalance valve configured to block the flow of hydraulic fluid when in a neutral position to prevent unintended movement of a power machine, and an anti-cavitation valve configured to direct flow of hydraulic fluid back to the travel motor to prevent cavitation.

A work machine including: a hydraulic cylinder 20 configured to drive a work implement 3; a control valve 22 configured to connect a delivery line of a hydraulic pump 21 switchingly to a bottom fluid chamber and a rod fluid chamber of the hydraulic cylinder 20 and a tank; a pilot pump 23 configured to output a pilot pressure to drive the control valve 22; an engine 24 configured to drive the hydraulic pump 21 and the pilot pump 23; and an accumulator 26 configured to accumulate a return hydraulic fluid from the hydraulic cylinder 20 is provided with: a bypass line 41 configured to connect the bottom fluid chamber of the hydraulic cylinder 20 and a delivery line 21a of the hydraulic pump 21 by bypassing the control valve 22 and be provided with the accumulator 26 thereon; a pressure-accumulation control valve 27 provided between the bottom fluid chamber of the hydraulic cylinder 20 and the accumulator 26; a release control valve 28 provided between the accumulator 26 and the delivery line 21a; and a hydraulic system controller 30 configured to open the release control valve 28 if an engine revolution speed N becomes lower than a set value Ns.

A work machine including: a hydraulic cylinder 20 configured to drive a work implement 3; a control valve 22 configured to connect a delivery line of a hydraulic pump 21 switchingly to a bottom fluid chamber and a rod fluid chamber of the hydraulic cylinder 20 and a tank; a pilot pump 23 configured to output a pilot pressure to drive the control valve 22; an engine 24 configured to drive the hydraulic pump 21 and the pilot pump 23; and an accumulator 26 configured to accumulate a return hydraulic fluid from the hydraulic cylinder 20 is provided with: a bypass line 41 configured to connect the bottom fluid chamber of the hydraulic cylinder 20 and a delivery line 21a of the hydraulic pump 21 by bypassing the control valve 22 and be provided with the accumulator 26 thereon; a pressure-accumulation control valve 27 provided between the bottom fluid chamber of the hydraulic cylinder 20 and the accumulator 26; a release control valve 28 provided between the accumulator 26 and the delivery line 21a; and a hydraulic system controller 30 configured to open the release control valve 28 if an engine revolution speed N becomes lower than a set value Ns.

An electrohydraulic system includes a hydraulic load and at least one closed hydraulic circuit. The hydraulic circuit includes at least one control mechanism, a hydraulic machine, and a closed hydraulic reservoir. The closed hydraulic circuit is filled with degassed hydraulic fluid. A method, in one embodiment, includes filling the electrohydraulic system with degassed hydraulic fluid. In one embodiment, equipment is provided for filling the electrohydraulic system with the degassed hydraulic fluid