A metering needle for an oleo-pneumatic-type shock absorber includes a base made of thermoplastic material, from which projects a rod arranged to control the flow of a hydraulic fluid through an orifice. The base has an arched bottom for withstanding pressure forces, in which is mounted an insert arranged to mechanically reinforce the arched bottom and distribute the pressure forces evenly.

A hydraulic shock absorber including a housing and an absorber unit. The absorber unit is movable relative to the housing in the axis direction of an absorber unit middle axis A-A and includes a piston which is arranged on a piston rod and which subdivides the housing into a first and a second working space which is filled with damping fluid.

The system is an improved valve/actuator architecture using a 4-way blocked-port architecture and area asymmetry providing numerous advantages over the conventional practice. The system uses fewer control circuits and provides for reduced component parts—it reduces hose, tubing and fitting requirements (lower cost, improved packaging, less installation labor and less leakage due to fewer connections). It also eliminates the need for a spring for static load support and other suspension control components (such as a sway bar). The system simplifies the mechanical design thereby reducing cost, aids in packaging, eliminates hysteresis losses of the spring and reduces moving mass thereby lowering response time. The system further allows regeneration of hydraulic power thereby increasing overall efficiency. The system further eliminates one half of throttling loss in a servo-valve.

A method of servicing a shock absorber of an aircraft landing gear shock absorbing strut, the shock absorber including a sealed, variable volume chamber containing a liquid and a gas in fluid communication with one another, the method comprising: using a mixer to mix the liquid and the gas within the chamber until the liquid is uniformly saturated with the gas; and subsequently performing one or more servicing actions.

A mechanical bypass for a shock assembly is disclosed herein. The assembly has a damper chamber having a compression portion and a rebound portion. There is further an external reservoir in fluid communication with the rebound portion of the damper chamber via a flow path. A valve is coupled with the flow path, the valve to meter a flow of the working fluid through the flow path. A bypass port to the external reservoir is provided in the flow path and bypasses the valve. A mechanical relief valve is provided in the bypass port to block a fluid flow though the bypass port until a blow-off pressure that is higher than a normal operating pressure and less than a burst pressure of the damping chamber is provided thereon.

A shock absorber includes; a free piston that partitions the compression chamber into an expansion-side compression chamber and a contraction-side compression chamber; an expansion-side flow passage that connects the expansion-side chamber with the expansion-side compression chamber; a contraction-side flow passage that connects the contraction-side chamber with the contraction-side compression chamber; an expansion-side bypass valve provided in the expansion-side flow passage to admit only a flow directed from the expansion-side chamber to the expansion-side compression chamber and generate resistance; a contraction-side bypass valve provided in parallel with the expansion-side bypass valve to admit only a flow directed from the expansion-side compression chamber to the expansion-side chamber and generate resistance; an expansion-side elastic stopper configured to stop the free piston at an expansion-side stroke end; and a contraction-side elastic stopper configured to stop the free piston at a contraction-side stroke end.

An aspect of the present disclosure provides a hydraulic-pneumatic apparatus including a cylinder assembly including a spindle with a hollow inside, a hollow cylinder portion, and a piston rod capable of reciprocating inside the hollow cylinder portion, and inserted through an inlet of the spindle, a flange portion surrounding the piston rod, disposed on an inlet side of the cylinder portion, and contacting an inner circumferential surface of the spindle, and a sealant disposed between the flange portion and one surface of the bent portion facing the flange portion, wherein a bent portion is formed on an inlet of the spindle to surround the flange portion.

The cylinder rod of a hydraulic cylinder includes a body portion having a bar shape, and a head portion arranged at a longitudinal end of the body portion. The body portion has a coating formed on its outer peripheral surface. The coating includes, in terms of area ratio in cross section, not less than 56.1% and not more than 84.4% of a chromium carbide phase, with the remainder consisting of a nickel-based alloy phase and an oxide phase. The area ratio of the chromium carbide phase may be 61.7% or more.

Disclosed herein is a single shock body equipped with the gas permeable internal floating piston. The gas permeable internal floating piston was specifically designed for installation in the multiple stage air shock, the gas permeable internal floating piston being disclosed in the parent application. The gas permeable internal floating piston automatically separates the oil from the gas within the shock body thereby significantly reducing the complexity and cost of manufacturing a shock absorber with the gas permeable internal floating piston. Also, separation is maintained during the operation of the shock throughout the shock's lifetime. The gas permeable internal floating piston can operate with oils derived from either petroleum or synthetic base stocks, additives, and various gases including dry air, nitrogen, oxygen, carbon monoxide, carbon dioxide, helium, neon, and argon.

The present invention provides a shock absorber capable of improving responsiveness during an extension stroke without leading to an increase in an axial length. A shock absorber includes a chamber provided on a one-side end of a pilot valve and disposed in communication with a cylinder upper chamber, a communication passage configured to establish communication between the chamber and a cylinder lower chamber via a compression-side passage, and a check valve configured to permit hydraulic fluid in the communication passage to flow into the cylinder lower chamber during an extension stroke.