A control device for at least one hydraulic working section (A, B), which can be connected to a pressure supply source (P) and a return flow (T) via a hydraulic supply circuit and to a control valve (34) supplied with a pilot pressure. The device includes an emergency shutdown system (32) having a pilot solenoid valve (16) and an additional valve (14). Both the hydraulic energy flow from the pressure supply source (P) to at least one of the respective working sections (A, B) and the pilot pressure supply to the control valve (34) can be suppressed by the pilot solenoid valve (16) via the additional valve (14).

A bootstrap hydraulic reservoir includes a bootstrap chamber to hold hydraulic fluid, a piston chamber fluidly connected to a pressure line of the hydraulic fluid system, a piston having a bootstrap end portion held within the bootstrap chamber and a pressure end portion held within the piston chamber, and a hydraulic accumulator fluidly connected to the pressure line of the hydraulic fluid system. The hydraulic accumulator accumulates pressurized hydraulic fluid from the pressure line. The bootstrap hydraulic reservoir also includes a valve fluidly connected to the pressure line of the hydraulic fluid system between the hydraulic accumulator and an outlet of a pump of the hydraulic fluid system. The valve includes an actuator selectively moves the valve to an open position when the pressure line of the hydraulic fluid system is de-pressurized.

An electric motor-driven, rolling element screw linear actuator is presented which work in cooperation with an hydraulic actuator and share several components. This is achieved through the integration of a screw-driven integrated nut piston assembly. Combining the use of an electric screw driven actuator can also reduce the need for a redundant hydraulic system, resulting in the elimination of 50% of connections, valves, piping, pumps, filters etc., while still being 100% redundant. An additional advantage is that the two drive systems are technologically independent, and therefore will not both fail because of an identical component flaw or failure point. The systems may also be used at the same time if conditions require force in excess of that generated by the hydraulic actuator alone.

A drive system of a construction machine includes: a controller that controls a fuel injection valve, so an actual rotation speed of an engine is adjusted to a setting rotation speed; a hydraulic circuit including a boom cylinder supplied with hydraulic oil from a pump driven by the engine, configured so energy is regenerated as motive power owing to the pump being driven by pressurized oil discharged from the boom cylinder at boom lowering; and a boom operation device including a boom operation lever. At boom lowering, the controller cuts a fuel supply to the engine when a cutting condition is satisfied, which is defined to include that an operating amount of the lever is less than or equal to a first threshold, and resumes the fuel supply when the cutting condition stops being satisfied or when the actual rotation speed of the engine becomes less than a second threshold.

An oil supply system for a vehicle includes a plurality of oil pumps, suction oil passages, and a communication passage. The oil pumps are independently operational. The suction oil passages each connect an associated one of suction portions of the plurality of oil pumps and a common oil strainer. The communication passage connects the suction oil passages.

A hydraulic circuit for a pair of cylinders of an articulation system includes a pump, a reservoir, a directional control valve (DCV), a pair of actuator valves (AVs) and an articulation charge circuit (ACC). The DCV is fluidly coupled to the pump, the reservoir and the pair of cylinders via a supply line, a fluid return line and a pair of cylinder supply lines (CSLs) respectively. Each CSL has a load check valve (LCV) therein. The AVs are fluidly coupled with the DCV and the pump via a pilot supply line (PSL) for actuating movement of the DCV. The ACC, associated with the PSL and each cylinder supply line downstream of the associated LCV, charges a corresponding CSL with fluid from the PSL for increasing a pressure in the corresponding CSL when the pressure in the corresponding CSL falls below the pressure of fluid associated with the PSL.

A steam turbine valve drive apparatus in an embodiment includes a piston, a cylinder, a bidirectional pump, a servo motor, and a quick closing mechanism. The cylinder houses the piston in an inner space thereof, the inner space being partitioned by the piston into a first hydraulic chamber and a second hydraulic chamber. The quick closing mechanism executes a quick closing operation of closing the steam valve unit more quickly than the closing operation. Here, the quick closing mechanism executes the quick closing operation by feeding the working oil accumulated in an accumulator to the second hydraulic chamber and draining the working oil from the first hydraulic chamber.

A hydraulic circuit for a pair of cylinders of an articulation system includes a pump, a reservoir, a directional control valve (DCV), a pair of actuator valves (AVs) and an articulation charge circuit (ACC). The DCV is fluidly coupled to the pump, the reservoir and the pair of cylinders via a supply line, a fluid return line and a pair of cylinder supply lines (CSLs) respectively. Each CSL has a load check valve (LCV) therein. The AVs are fluidly coupled with the DCV and the pump via a pilot supply line (PSL) for actuating movement of the DCV. The ACC, associated with the PSL and each cylinder supply line downstream of the associated LCV, charges a corresponding CSL with fluid from the PSL for increasing a pressure in the corresponding CSL when the pressure in the corresponding CSL falls below the pressure of fluid associated with the PSL.

A throttle assembly for a pressure control system in a vehicle includes at least one throttle valve. The at least one throttle valve defines an assembly cross-section of the throttle assembly, the assembly cross-section specifies a flow resistance acting on a pressure medium entering the throttle assembly, and the at least one throttle valve includes at least one controllable throttle valve configured to be controlled in accordance with an upstream pressure. The assembly cross-section of the throttle assembly is configured to be set, by control of the at least one controllable throttle valve, in such a way that an inlet volume flow of the pressure medium entering the throttle assembly can be limited to a limit volume flow in accordance with the upstream pressure, in order to set, in accordance with the upstream pressure, a power consumption of a pneumatic load in the pressure control system.

A system for recovering energy from a hydraulic actuator and to a method of operating the system are described. The system may have a hydraulic actuator and a source of hydraulic pressure, comprising a hydraulic pump, in fluid communication with the hydraulic actuator for pressurizing the hydraulic actuator. The system may also have a hydraulic accumulator assembly for selectively absorbing energy from the hydraulic actuator or via the hydraulic actuator. The system may also have a first one-way valve configured to provide fluid communication between the hydraulic actuator and the hydraulic accumulator assembly. The first one-way valve may be configured to permit a flow of fluid through the first one-way valve from the hydraulic actuator to the hydraulic accumulator assembly. The first one-way valve may also be configured to block a flow of fluid through the first one-way valve from the hydraulic accumulator assembly to the hydraulic actuator.