Controllable oleo-pneumatic damper using magnetorheological fluid

An oleo-pneumatic damper using magnetorheological fluid, the damper having a controllable load-stroke profile, the damper comprising:

• a hollow cylindrical housing having a first circular end and a second circular end;
• a hollow cylindrical piston disposed within and concentric to the hollow cylindrical housing, the hollow cylindrical piston having a first piston end, a second piston end, and a piston inner surface, the second piston end being closed such that fluids may be contained within the piston;
• an annular electromagnetic orifice disposed at the first piston end, the electromagnetic orifice concentric to the hollow cylindrical housing, the electromagnetic orifice formed by an orifice casing and an annular electromagnet that are concentric to each other, the annular electromagnet having exterior facing sides and an inner bore and being made from wound conductive wire, the orifice casing completely surrounding the exterior facing sides of the annular electromagnet and having circular lumen that form a bore that is flush with the inner bore, the orifice casing being made from a material with high magnetic permeability and a high magnetic flux density saturation point;
• a bulkhead disposed within the hollow cylindrical piston, the bulkhead having a bulkhead outer diameter and a sealing system that forms a dynamic seal with the piston inner surface such that a sliding barrier is formed in the hollow cylindrical piston, magnetorheological fluid disposed between the bulk head and the first circular end of the hollow cylindrical piston;
• a chemically inert charging gas, disposed within the hollow cylindrical piston between the closed second piston end and the bulkhead, the dynamic seal forms the sliding barrier in the piston to separate the magnetorheological fluid from the charging gas;
• a cylindrical metering pin disposed within the housing and the piston, the metering pin being concentric to the housing and attached to the first circular end of the housing, the metering pin being surrounded by magnetorheological fluid, the metering pin being made from a material with high magnetic permeability and a high magnetic flux density saturation point, the metering pin extending through the inner bore of the annular electromagnet such that the flow of the magnetorheological fluid is channeled between the metering pin and the electromagnetic orifice when magnetorheological fluid is pushed by the hollow cylindrical piston, the metering pin allows a magnetic circuit to be completed between the metering pin and the orifice casing when electrical power is applied to the annular electromagnet such that magnetic field lines from the electromagnet become locally oriented perpendicular to flow direction of the magnetorheological fluid;
• and,
• a controller, that includes sensors, that allows for passive, semi-active, or active control of the load-stroke profile for the damper by adjusting damping characteristics of the damper.