Query: Aircraft landing gear reciprocating  seal

title: Seal performance test device of airplane landing gear buffer
abstract: The sealing performance test device of the aircraft landing gear buffer comprises a servo cylinder mounted on the test stand, a piston rod for reciprocating motion under the hydraulic drive, a test cylinder, a actuator and a detection mechanism; one end of the piston rod passes through the servo cylinder; a cylindrical boss is arranged in the middle of the piston rod located in the servo cylinder. The cylindrical boss divides the inner cavity of the servo cylinder into a left cavity and a right cavity, and the ends of the left cavity and the right cavity are respectively provided with a first drive oil source inlet and a second drive oil source inlet; one end of the piston rod is connected with the actuator through a spherical joint; the first groove of the inner cylinder surface of the test cylinder is provided with a first groove, and the first groove is provided with actuator; there is a gap between the first groove and the outer wall of the actuator; the gap between the first groove and the outer wall of the actuator forms a hydraulic oil chamber; each side of the hydraulic oil chamber is provided with a hydraulic oil inlet and a circulating oil return port respectively; one end of actuator that is far away from the piston is connected to the detection mechanism, and a displacement sensor is installed at the end of the detection mechanism.

title: Parametric and Optimization Study of Rectangular Rounded, Hydraulic, Elastomeric, Reciprocating Seals at Temperatures between 54 and +135 degC
abstract: Hydraulic, reciprocating, polymeric seals are met in many engineering applications and are critical components for mechanism and machine reliability in industries including the automotive, marine, and aerospace industries. A parametric and optimization study of rectangular rounded, hydraulic, reciprocating, elastomeric rod seals at 54, +23, and +135 degC is presented, which is particularly relevant to hydraulic actuators in aircraft landing gear. Parametric optimization not only improves performance, but also helps avoid sealing failures. The calculations were based on a physically based, deterministic mathematical model of such seals, experimentally validated at the aforementioned temperatures and recently published by the author. The parameters varied were the seal axial width and corner radius, seal elastic modulus, sealed pressure, stroking velocity, operating temperature, rod surface roughness, seal radial interference, and seal swelling by fluid uptake. Their influence was established based on the following performance variables: leakage rate, frictional force, coefficient of friction, temperature rise in the sealing contact, lambda ratio (proportional to the average film thickness in the contact) and ratio of the asperity friction force to the total friction force. The parametric study greatly facilitates the selection of optimal values of the analyzed parameters to minimize leakage, friction, and wear, either concurrently as a set or individually, depending on application priorities.

title: Element analysis and wear longevity calculation of an O ring in the actuator cylinder of a certain aircraft landing gear
abstract: In this paper, we established the finite element model of an O ring in the actuator cylinder of a certain aircraft landing gear in order to analyze the O ring's Von Mises stress and contact stress and to compute its wear longevity. The contact mechanics characteristic of the O ring under working status is simulated through the ABUQUS. We adopt the Mooney Rivlin hyperplastic material model to keep the results reasonable. The geometric nonlinearities, the material nonlinearities and the nonlinear boundary conditions are also considered. The simulation provided us with the convergent solution in full stroke of actuator cylinder, i.e. the distribution of Von Mises stress and contact stress of the O ring. Basing on the stress distribution above, we compute the O ring's wear volume and the wear longevity through the wear longevity predicting model under common working status. The stress distribution and wear longevity can provide critical references for the engineering design and application of O ring in the actuator cylinder, meanwhile they can be further applied in the safety analysis of aircraft landing gear actuator cylinder seal.

title: Method of servicing an aircraft landing gear shock absorbing strut
abstract: A method of servicing a shock absorber of an aircraft landing gear shock absorbing strut (12) 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 (14) 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.

title: Aircraft landing gear line protection method
abstract: The invention discloses an aircraft landing gear line protection method. The aircraft landing gear line protection method comprises the following steps that independent line protection has the following concrete steps that step 1: clustering is performed on cables requiring arrangement of common connecting plugs of multiple cables; step 2: each wire harness is wound by a binding belt; step 3: all the wire harnesses are sleeved in a bellows respectively; step 4: all the wire harnesses are sleeved in a wave preventing sleeve respectively; step 5: multiple shielding line deconcentrators are manufactured, each shielding line deconcentrator is provided with one input end, and the wire harnesses enter the input end of each shielding line deconcentrator and then shunted to stretch out of each output end of the shielding line deconcentrator; step 6: all the wireless harnesses are sleeved in a thermal shrinkable bushing; and step 7: the end parts of all the wire harnesses are respectively connected with the plugs. According to the aircraft landing gear line protection method, electromagnetic protection, mechanical protection and sealed waterproof protection can be realized simultaneously.

title: Experiments on Grease Performance in Aircraft Landing Gear Pin Joints
abstract: A pin joint simulation machine has been built to test a real landing gear pin joint under realistic loading and reciprocation conditions. The pin is loaded hydraulically using a hydraulic actuator to apply a fixed displacement cycle whilst measuring the reactive torque. The machine was used to measure the torque cycle (and hence friction coefficient) required to operate the joint. In this work a method of evaluating different formulation greases has been proven. This involved measuring their frictional torque and also evaluating performance using a Sommerfeld type approach that displays the different lubrication regimes in the joint for different conditions. Measured friction coefficients were in the region of 0.02 to 0.12 depending on the joint load and articulating speed. In actual gear the surface sliding speed is low and so the joint operates in the boundary regime. The required torque and coefficient of friction have been related to the lubrication mechanisms occurring as a function of articulation angle, reciprocal frequency and applied axial load for lubrication starvation in a reciprocating journal bearing.

title: The Load Simulation Research of Nose Landing Gear Steering
abstract: The nose landing gear is a vital component of an aircraft,which has an important impact on the safety of the aircraft.This paper studies the system of nose landing gear steering on the basis of the gear and rack mechanism durability test of a certain type of civil aircraft landing gear steering. Furthermore,it puts forward a method of passive loading,which can simulate the friction when the nose landing gear reciprocating turning,and establishes the mathematical model. The simulation results show that the simulator can meet the requirements of load,and laid a theoretical foundation for the subsequent actual work.

title: A Novel Structure of Rubber Ring for Hydraulic Buffer Seal Based on Numerical Simulation
abstract: Landing gear is a key load bearing structure of aircraft during ground operation, and the landing capacity of landing gear is determined by the performance of buffer. To solve the problem of buffer failure caused by insufficient static sealing of a rubber ring at groove side, a new structure of a butterfly rubber ring is proposed by analyzing the factors affecting sealing performance of the rubber ring. First, the constitutive equation of rubber material is derived based on the theory of hyper elasticity, and the material parameters are obtained by fitting the experimental data. Then, by analyzing the simulation method of installation mode and installation stroke, the simulation method suitable for calculating the sealing performance of the rubber ring is established. The linear fitting formulas with Pearson coefficient greater than 0.92 are used to discuss the influence of pre compression rate and hydraulic pressure on the sealing performance of the rubber ring. Compared with O ring, the contact pressure of butterfly ring is increased by 30% in assembly state and 14% in working state. The results show that the butterfly rubber ring has excellent static sealing performance. It is concluded that improving the configuration of the sealing ring can solve the insufficient unilateral sealing of the hydraulic buffer.

title: Placing the front compartment of the aircraft landing gear
abstract: 1. Compartment chassis placement front support for the aircraft having a plurality of retractable landing gear comprising a front support (4) chassis, centered on the longitudinal median plane of the fuselage (1) wherein the accommodation compartment forms a sealed partition between a pressurized zone of the aircraft and the recess for the front support chassis in its folded position! characterized in that it has an upper reinforced face comprising a substantially flat and substantially horizontal zone when the aircraft is on the ground, so as to form a sealed floor plane of the room. 2. placing compartment nose landing gear according to claim 1, characterized in that the upper surface has a second substantially flat zone, substantially parallel to the first flat zone, at a lower level. 3. accommodation compartment nose landing gear according to claim 2, characterized in that the two flat zones are connected to each other a ladder (34) integrated into the upper surface enhanced accommodation compartment. 4. The front part of an aircraft comprising a fuselage, a cockpit disposed at the front of the fuselage and having a floor, and the front landing gear and landing gear compartment placement front leg, characterized in that the compartment front support chassis placement is the accommodation compartment in accordance with one of the claims 1 3. 5. The front part of an aircraft according to claim 4, characterized in that the upper surface (51) placement of nose landing gear compartment constitutes at least a part of the floor (31) the cab (2) of the crew. 6. The front part of an aircraft according to claim 5, characterized in that it comprises an access corridor to the cab (2) of the crew, in order,

title: Landing gear uplock
abstract: The invention provides a landing gear uplock which relates to the field of aircraft design. According to the landing gear uplock, a normal unlocking piston, an emergency unlocking piston and seal rings thereof are closed in a cavity of a shell by the shell and a plug cover which are screwed with each other; a lock hook and a manual unlocking rocker arm are arranged on the shell through bolt shafts; certain uplock force is kept for the lock hook by a torsion spring which is arranged at the rotating shaft of the lock hook; both a hook and a guide member are connected to the shell through bolts; the hook is provided with a torsion spring; when a landing gear is not folded, the hook is kept at an unlocking position; the manual unlocking rocker arm is fixedly arranged on a positioning pin on the shell through a retaining spring; a normal unlocking oil inlet nozzle, an emergency unlocking oil inlet nozzle and an oil return nozzle are arranged on the lock shell to provide an oil supply port and an oil return port; a dust proof cover is fixedly arranged on the tail part of the shell through gluing; a hook ring assembly is fastened to a landing gear support column through four hole bolts at the bottom to move together with the landing gear. The landing gear uplock has higher reliability.