A piston accumulator, having an accumulator housing and a separating piston (8) guided for longitudinal motion therein, wherein said separating piston separates a liquid side (4) from a gas side (10) in the accumulator housing, and wherein liquid unintentionally transitions from the liquid side (4) to the gas side (10) despite a piston seal on the separating piston (8), is characterized in that, by means of a return device (28) the transitioned liquid is at least partially returned from the gas side (10) of the accumulator housing to the liquid side (4) of the latter.

A hydraulic system for a working machine includes a hydraulic actuator having a first fluid chamber and a second fluid chamber, an accumulator, an outputting fluid tube to output an operation fluid, and a switching valve to be switched between a first position and a second position. The first position allows the first fluid chamber and the second fluid chamber to be communicated with the outputting fluid tube and thereby allowing a floating operation. The second position allows the first fluid chamber and the accumulator to be communicated with each other, allows the second fluid chamber and the outputting fluid tube to be communicated with each other, and thereby allows an anti-vibration operation.

A device for controlling the compression rate of a variable compression ratio engine comprises: an actuating cylinder comprising a piston defining two chambers for receiving a pressure fluid, a pressure accumulator supplying the pressure fluid, a first fluid circuit connecting the upper chamber to the accumulator and comprising a first valve assembly for controlling the flow of the fluid in the first fluid circuit, and a second fluid circuit connecting the lower chamber to the accumulator and comprising a second valve assembly for controlling the flow of a fluid in the second fluid circuit. At least one of the fluid circuits comprises a bypass conduit arranged so as to connect one of the chambers to the accumulator. The bypass conduit comprises a non-return valve.

A hydraulic system for a working machine includes a hydraulic actuator having a first fluid chamber and a second fluid chamber, an accumulator, an outputting fluid tube to output an operation fluid, and a switching valve to be switched between a first position and a second position. The first position allows the first fluid chamber and the second fluid chamber to be communicated with the outputting fluid tube and thereby allowing a floating operation. The second position allows the first fluid chamber and the accumulator to be communicated with each other, allows the second fluid chamber and the outputting fluid tube to be communicated with each other, and thereby allows an anti-vibration operation.

This disclosure includes systems and methods for actuating hydraulically-actuated devices.

Some of the present systems include a hydraulic power storage system having an accumulator configured to supply pressurized hydraulic fluid to a hydraulically actuated device to actuate the hydraulically actuated device and a drain in fluid communication with the accumulator and including a valve that is actuatable to drain hydraulic fluid from the hydraulic power storage system such that an internal pressure of the accumulator is reduced and a flow restrictor configured to reduce a flow rate of hydraulic fluid through the valve, a hydraulic pump configured to pressurize the accumulator, a pressure sensor configured to capture data indicative of the internal pressure of the accumulator, and a processor configured to actuate the hydraulic pump to increase the internal pressure of the accumulator if the internal pressure of the accumulator, as indicated in data captured by the pressure sensor, falls below a threshold pressure.

Device for recovering hydraulic energy in a machine comprising at least a first differential cylinder-piston assembly having a differential cylinder with a separate rod and base side, at least a second differential cylinder-piston assembly having a differential cylinder with a separate rod and base side, and at least one hydraulic accumulator that can be hydraulically connected to at least one of the differential cylinder-piston assemblies, wherein the differential cylinder-piston assemblies are mechanically coupled to one another, and wherein the potential energy of at least one of the differential cylinder-piston assemblies retracting under a compressive load can at least partially be stored in the hydraulic accumulator.

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.

A method for producing a foam body for a pressure or hydraulic accumulator has a bubble- or diaphragm-shaped, elastically flexible separating layer (12) separating gas and liquid chambers from each other within an accumulator housing. The production method includes introducing a flowable, preferably liquid, foam material into the pressure accumulator with the foam material being at least partially surrounded by the separating layer (12), curing the foam material in the hydraulic accumulator, and building up a pressure gradient in which the visibly curing foam material expands the separating layer (12) from an originally partially filled starting state in the direction of an end state in which the accumulator is finally filled with the cured foam (38).

A valve system includes: a valve; a hydraulic cylinder attached to at least a portion of the valve; and at least a first accumulator in fluid communication with the hydraulic cylinder. The first accumulator includes: (i) a first end having a fluid inlet and a fluid outlet; (ii) a second end having a gas inlet; and (iii) a body positioned between the first end and the second end and which includes a fluid chamber and a gas chamber separated by a flexible separating member. The hydraulic cylinder is configured to close the valve in response to pressure provided by fluid distributed from the first accumulator.