Hydraulic damper for shimmy of aircraft landing gear

A hydraulic system for steering a landing gear wheel of an aircraft while taxiing and having a supply line carrying pressurized fluid from a source and a return line that conveys fluid to a reservoir, the hydraulic system comprising:

• a hydraulic motor operatively connected to turn the landing gear wheel and having first and second ports;
• a first intermediate conduit and a second intermediate conduit;
• a flow control valve arrangement having a first state in which the first intermediate conduit is connected to the supply line and the second intermediate conduit is coupled to the return line, a second state in which the first intermediate conduit is connected to the return line and the second intermediate conduit is coupled to the supply line, an third state in which the first intermediate conduit and the second intermediate conduit are disconnected from the supply line and the return line;
• and
• a damper having a bore with a piston slidably received therein and defining a first chamber and a second chamber in the bore on opposite sides of the piston, the second chamber is coupled to the second intermediate conduit, wherein the piston moves within the bore uninfluenced by any fastening external to the bore, and the damper having a first orifice connected between the first intermediate conduit and the first chamber.

A hydraulic system for steering a landing gear wheel of an aircraft while taxiing and having a supply line carrying pressurized fluid from a source and a return line that conveys fluid to a reservoir, the hydraulic system comprising:

• a hydraulic motor operatively connected to turn the landing gear wheel and having first and second ports;
• a first intermediate conduit and a second intermediate conduit;
• a flow control valve having a first position in which the first intermediate conduit is connected to the supply line and the second intermediate conduit is coupled to the return line, a second position in which the first intermediate conduit is connected to the return line and the second intermediate conduit is coupled to the supply line, an third position in which the first intermediate conduit and the second intermediate conduit are disconnected from the supply line and the return line;
• a shutoff valve having a first state in which the first intermediate conduit is connected to the first port of the motor and the second intermediate conduit is connected to the second port of the motor, and a second state in which first intermediate conduit and the second intermediate conduit are disconnected from the first port and the second port and a damping orifice is connected between the first port and the second port;
• and
• a damper having a bore with a piston slidably received therein and defining a first chamber and a second chamber in the bore on opposite sides of the piston, a first orifice connected between the first intermediate conduit and the first chamber, and a second orifice connected between the second intermediate conduit and the second chamber.