Shock strut with pressure relief

摘要

A shock strut includes a relief device that reduces the internal pressure within a sealed chamber of the shock strut when a load condition that exceeds a maximum operating load condition is encountered. The reduced pressure permits a telescopically moving piston of the shock strut to be received into a corresponding cylinder to an amount that increases the structural capability of the shock strut, especially with respect to applied side loads that generate bending and shearing stresses in the shock strut. In one embodiment, the reduced pressure permits the piston to “bottom out” relative to the cylinder, which is a condition not otherwise achievable without the relief device. This additional stroke achievable by the piston reduces or eliminates the need to reinforce and thus add weight to the shock strut because of higher load condition design requirements.

主权项

1. An aircraft landing gear shock strut, comprising:
a cylinder; a piston telescopically movable within the cylinder to provide a piston-cylinder assembly; a sealed chamber defined by an arrangement of the piston-cylinder assembly, the sealed chamber having an upper section and a lower section separated by an upper piston, the upper section and the lower section each having a compressible gas that resists movement of the piston relative to the cylinder in response to a load applied to the strut causing the piston to compress the compressible gas, wherein the upper piston is configured to move toward the upper section in response to pressure in the sealed chamber exceeding a first pressure threshold; and a relief device in fluid communication with the upper section, the relief device configured to release at least some of the compressible gas in response to the pressure in the sealed chamber exceeding a second pressure threshold that is higher than the first pressure threshold, wherein the second pressure threshold is above a maximum operating pressure of the aircraft landing gear shock strut, and wherein the amount of compressible gas released is sufficient to reduce the pressure in the sealed chamber and thereby permit the piston to extend telescopically further into the cylinder by an amount that increases at least a bending strength capability of the piston-cylinder assembly, and wherein the relief device includes an accumulator in fluid communication with the sealed chamber, the accumulator configured to receive a quantity of the compressible gas from the sealed chamber.