# US 10,501,172 B2 · Aircraft landing gear assembly

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- Number: US 10,501,172 B2
- Document ID: US10501172B2
- Status: Granted
- Kind: B2
- Application number: 15/477,770
- Filed: 2017-04-03
- Published: 2017-10-12
- Granted: 2019-12-10
- Earliest claimed: 2016-04-06
- Assignees: Safran Landing Systems UK LTD
- Applicants: Safran Landing Systems UK Limited
- Inventors: Nicholas Foster; Sam Evans
- Web page: https://patentgrep.com/patent/US10501172B2

## CPC

- B64C 25/10: retractable, foldable, or the like
- B64C 25/34: wheeled type, e.g. multi-wheeled bogies
- B64C 25/36: Arrangements or adaptations of wheels, tyres or axles in general
- B65G 23/04: Drums, rollers, or wheels {(B65G23/18 takes precedence)}
- B65G 39/06: the roller sleeves being shock-absorbing, e.g. formed by helically-wound wires
- E21B 19/22: Handling reeled pipe or rod units, e.g. flexible drilling pipes {(lifting or hauling appliances using two or more cooperating endless chains B66D3/003)}
- F16C 13/006: {Guiding rollers, wheels or the like, formed by or on the outer element of a single bearing or bearing unit, e.g. two adjacent bearings, whose ratio of length to diameter is generally less than one}
- F16C 33/203: {Multilayer structures, e.g. sleeves comprising a plastic lining}
- F16C 33/205: {with two layers}
- F16C 33/208: {Methods of manufacture, e.g. shaping, applying coatings}
- E21B 2200/03: Valves operated by gear mechanisms, e.g. rack and pinion mechanisms
- F16C 2208/02: comprising fillers, fibres
- F16C 2326/43: Aeroplanes; Helicopters
- B64C: AEROPLANES; HELICOPTERS
- B65G: TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS (packaging B65B; handling thin or filamentary materials, e.g. paper sheets or thread, B65H; cranes B66C; portable mobile or lifting or hauling appliances, e.g. hoists, B66D; devices for lifting or lowering goods for loading or unloading purposes, e.g. fork-lift trucks, B66F9/00; emptying bottles, jars, casks, barrels or similar containers, not otherwise provided for, B67C9/00; delivering or transferring liquids B67D; filling or discharging vessels for liquefied, solidified or compressed gases F17C; pipe-line systems for fluids F17D)
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS

## Abstract

An aircraft landing gear assembly including structural members coupled via a coupling including a bearing. The bearing has a body defining a first bearing surface arranged to contact a first counter-face of the coupling. The first bearing surface is defined by a first tubular layer of fibre reinforced polymer of a first type having an axis and containing synthetic fibres of a first type wound around and along the axis of the bearing. The bearing body further has a second tubular layer of fibre reinforced polymer of a second type containing synthetic fibres of a second type wound around and along the axis of the bearing.

## Claims

### Claim 1

An aircraft landing gear assembly comprising a first structural member coupled to a second structural member via a mechanical coupling, the mechanical coupling comprising a bearing, the bearing defining a first bearing surface arranged to contact a first counter-face of the coupling, the first bearing surface being defined by a first tubular layer of fibre reinforced polymer of a first type having an axis and containing synthetic fibres of a first type wound around and along the rotation axis of the first tubular layer, the bearing further comprising a second tubular layer of fibre reinforced polymer of a second type containing synthetic fibres of a second type wound around and along the rotation axis of the first tubular layer, wherein one of the first and second fibre reinforced polymers has greater compressive loading capability than the other and the other of the first and second fibre reinforced polymers comprises dry lubricant particles.

### Claim 2 (depends on 1)

The aircraft landing gear assembly according to claim 1, wherein the polymer of the first type comprises an epoxy, a resin or a thermoset material and/or the polymer of the second type comprises an epoxy, a resin or a thermoset material.

### Claim 3 (depends on 1)

The aircraft landing gear assembly according to claim 1, wherein the synthetic fibres of the first type and the second type are continuous fibres.

### Claim 4 (depends on 1)

The aircraft landing gear assembly according to claim 1, wherein the bearing has a second bearing surface arranged to contact a second counter-face of the coupling, the body separating the first bearing surface from the second bearing surface such that a thickness of a tubular body of the bearing is defined between the first and second bearing surfaces, wherein the thickness of the first layer is less than ¼ that of the total thickness of the bearing body.

### Claim 5 (depends on 1)

The aircraft landing gear assembly according to claim 1, wherein the coupling is arranged to movably couple the first structural member to the second structural member such that the first counter-face of the coupling moves relative to the first bearing surface.

### Claim 6 (depends on 5)

The aircraft landing gear assembly according to claim 5, wherein the first bearing surface and the first counter-face are each circular in cross section such that the coupling is arranged to permit rotation of the first structural member relative to the second structural member about the rotation axis of the first tubular layer.

### Claim 7 (depends on 5)

The aircraft landing gear assembly according to claim 5, wherein the coupling comprises a pin mounted within holes formed through the first and second structural members so as to define a pin joint, the bearing being provided between the pin and one or more of the first and second parts, the pin defining the first counter-face of the coupling.

### Claim 8 (depends on 1)

The aircraft landing gear assembly according to claim 1, wherein the bearing includes a radial flange at one end.

### Claim 9 (depends on 1)

The aircraft landing gear assembly according to claim 1, wherein the bearing comprise a plurality of bearings, each bearing having a respective bearing surface arranged in contact with a respective counter-face of the coupling.

### Claim 10 (depends on 1)

The aircraft landing gear assembly according to claim 1, wherein the layer containing dry lubricant particles comprises epoxy containing particles of dry lubricant and a continuously woven mix of polytetrafluoroethylene (“PTFE”) fibres and carbon fibres.

### Claim 11 (depends on 10)

The aircraft landing gear assembly according to claim 10, wherein the layer having greater compressive loading capability comprises epoxy containing glass fibres.

### Claim 12

An aircraft including one or more aircraft landing gear assemblies, each aircraft landing gear assembly comprising a first structural member coupled to a second structural member via a mechanical coupling, the mechanical coupling comprising a bearing, the bearing defining a first bearing surface arranged to contact a first counter-face of the coupling, the first bearing surface being defined by a first tubular layer of fibre reinforced polymer of a first type having an axis and containing synthetic fibres of a first type wound around and along a rotation axis of the first tubular layer, the bearing further comprising a second tubular layer of fibre reinforced polymer of a second type containing synthetic fibres of a second type wound around and along the rotation axis of the first tubular layer, wherein one of the first and second fibre reinforced polymers has greater compressive loading capability than the other and/or wherein the other of the first and second fibre reinforced polymers comprises dry lubricant particles.

### Claim 13

A method of forming an aircraft landing gear assembly bearing, the method comprising:
forming a first tubular layer of fibre reinforced polymer of a first type having an axis and containing synthetic fibres of a first type wound around and along a rotation axis of the first tubular layer;
forming a second tubular layer of fibre reinforced polymer of a second type containing synthetic fibres of a second type wound around and along the outer surface of the first tubular layer; and
curing the first and second layers to form a consolidated tubular body;
wherein the one of the first and second fibre reinforced polymers has greater compressive strength characteristics than the other and/or wherein the other of the first and second fibre reinforced polymers contains dry lubricant particles.

### Claim 14 (depends on 13)

The method according to claim 13, further comprising forming a radial flange on the bearing by machining away a portion of the second tubular layer to leave a radial flange.

### Claim 15 (depends on 14)

The method according to claim 14, further comprising bonding a layer of self-lubricating material to an axial face of the flange.

### Claim 16 (depends on 13)

The method according to claim 13, further comprising forming a radial flange and bonding the radial flange to an axial end face of the tubular body.

### Claim 17

A method of forming or maintaining an aircraft landing gear assembly comprising a first structural member coupled to a second structural member via a mechanical coupling, the mechanical coupling comprising a bearing, the bearing defining a first bearing surface arranged to contact a first counter-face of the coupling, the method comprising:
fitting a bearing to the coupling, the bearing defining a first bearing surface arranged to contact the first counter-face of the coupling, the first bearing surface being defined by a first tubular layer of fibre reinforced polymer of a first type having an axis and containing synthetic fibres of a first type wound around and along a rotation axis of the first tubular layer, the bearing further comprising a second tubular layer of fibre reinforced polymer of a second type containing synthetic fibres of a second type wound around and along the rotation axis of the first tubular layer, wherein the one of the first and second fibre reinforced polymers has greater compressive strength characteristics than the other and/or wherein the other of the first and second fibre reinforced polymers contains dry lubricant particles.

### Claim 18 (depends on 17)

The method according to claim 17, whereby the method is a method of maintaining an aircraft landing gear, the method comprising a step of:
removing a worn bearing from the mechanical coupling prior to the step of fitting the bearing to the coupling.

### Claim 19 (depends on 1)

The aircraft landing gear of claim 1, wherein the rotation axis of the first tubular layer comprises a central axis of the first tubular layer.