In general, certain embodiments of the present disclosure provide an electro-hydrostatic actuator comprising a piston assembly and a hydraulic cylinder. The piston assembly, having a piston head and a piston rod extending from the piston head, is located and movable within the hydraulic cylinder. The hydraulic cylinder includes a hydraulic fluid chamber region including a piston side chamber and a rod side chamber, a reservoir for storing hydraulic fluid located within the hydraulic cylinder which is in fluid communication with the hydraulic fluid chamber region. The electro-hydrostatic actuator includes a hydraulic pump system for moving hydraulic fluid in the reservoir and the hydraulic fluid chamber region, the hydraulic pump system in fluid communication with a flow control network in a hydraulic cylinder boss for controlling a direction and flow magnitude of hydraulic fluid within the hydraulic fluid chamber region, and an electric motor for driving the hydraulic pump system.

Provided is an accumulator for easier maintenance of a metal bellows. The accumulator includes a housing having a shell provided with an opening portion and a disk-shaped base body to which one end of a metal bellows with an outside diameter smaller than the inside diameter of the opening portion is welded and fixed, the interior of the housing partitioned on the inside and outside of the metal bellows in a tightly closed manner, in which the base body is formed to have an outside diameter greater than the outside diameter of the metal bellows, and the base body is fixed detachably to the shell.

A center biased actuator having an outer cylinder, a slave cylinder linearly transposed within the outer cylinder, a rod assembly with a piston linearly transposed within the slave cylinder and a rod extending from the outer cylinder, one or more first dynamic seals arranged to act on a sidewall of the rod to inhibit hydraulic fluid leaking from the outer cylinder, one or more second dynamic seals arranged to act on a sidewall of the slave cylinder or an inner surface of the outer cylinder to inhibit hydraulic fluid leaking from the outer cylinder, and a gas chamber comprising a sealed expandable chamber containing gas. The expandable chamber is arranged to act on hydraulic fluid within the center biased actuator to bias the center biased actuator to assume an intermediate condition which lies between a compressed condition and an extended condition.

A diaphragm accumulator provided with a flexible diaphragm inside an accumulator housing has a stress relaxing member having a contact surface which the diaphragm deformed by a pressure fluctuation inside the accumulator housing contacts and regulating the deformed attitude of the diaphragm by the contact surface on the inner surface. When the diaphragm is deformed by the pressure fluctuation inside the accumulator housing, the stress relaxing member regulates the deformed attitude of the diaphragm to reduce a stress generated in the diaphragm.

A pressure accumulator having an accumulator housing (10) in which a movable separating element (16) separates a gas room (12) filled with a working gas from a fluid room (14) in a fluid-sealed manner, wherein a monitoring device (46) is provided, which, in the event of a fault impairing the sealing effect of the separating element (16), provides an optically discernible indication and which has an inspection window (54), through which an indicator can be observed, which is connected to the gas room (12) and whose optical properties change discernibly when wetted with the fluid, is characterized in that the indicator changing its optical properties is accommodated in a capsule (48), the capsule wall (50) of which is permeable to the passage of the fluid and which is arranged between the inspection window (54) and the separating element (16) in the accumulator housing (10).

A shell member 10 constituting an accumulator 100 including a cover member 30, a shell member 10 having a cylindrical portion 11, an opening portion 13 formed at one end of the cylindrical portion 11 and welded to the cover member 30, and a closed portion 12 formed at another end of the cylindrical portion 11, and an accumulation part 70 accommodated in the shell member 10. The cylindrical portion 11 includes an upper end portion 11a, and a protruding portion 11c having the opening portion 13. The protruding portion 11c is thicker than the upper end portion 11a.

The accumulator includes a housing having a sealing face and a fluid inlet/outlet passage; and a bellows fixed at one end to the housing such that an inner space of the housing is hermetically partitioned by the bellows into an interior and an exterior of the bellows. The bellows includes a bellows main body capable of expanding and contracting and a bellows cap provided with a sealing member covered with an elastic body that is opposed to and capable of being closely attached to the sealing face of the housing. The fluid inlet/outlet passage of the housing is closed upon a close attachment of the elastic body to the sealing face. The accumulator further includes a spacer placed between the housing and the bellows cap so as to surround the sealing member. The spacer has a communication passage providing communication between an inside and an outside of the spacer.

An accumulator includes a housing having a sealing face and a fluid inlet/outlet passage, a bellows fixed at least one end to the housing such that an inner space of the housing is hermetically partitioned by the bellows into an interior and an exterior of the bellows, the bellows including a bellows main body capable of expanding and contracting and a bellows cap including an annular seal holder, and a sealing member formed by covering a disc-shaped substrate with an elastic body that is opposed to and capable of being closely attached to the sealing face of the housing, the sealing member is held by a holding portion of the annular seal holder on an inner diameter side of the annular seal holder, the fluid inlet/outlet passage of the housing being closed upon a close attachment of the elastic body to the sealing face.

An accumulator includes a bellows 3 having a plurality of outer ridge portions and a plurality of inner annular ridge portions and configured to be capable of expanding and contracting, and a housing having a fluid supply port and fixed to one end of the bellows serving as a fixed end. An interior of the housing is partitioned in a sealed state into an inside and an outside of the bellows. The outer annular ridge portions are divided into at least a first sector and a second sector which are distributed in an expansion and contraction direction of the bellows such that the second sector is positioned between the first sector and the fixed end. The outer annular ridge portions included in the first sector have an outer diameter smaller than an outer diameter of the outer annular ridge portions included in the second sector.

An accumulator according to an embodiment includes, for example, a base member; a cover member welded to the base member, the cover member and the base member defining a pressure chamber therebetween; a stretchable partition member that partitions the pressure chamber into an inner chamber and an outer chamber; and a labyrinth structure provided in at least one of a first part of the base member and a second part of the cover member. The first part is located closer to the outer chamber than a welded part between the base member and the cover member. The second part is located closer to the outer chamber than the welded part, facing the first part.