An aircraft tire

Abstract

Disclosed is an aircraft tire comprising an external wall, and an internal support structure located within the external wall, wherein the internal support structure is arranged such that the external

Description

TECHNICAL FIELD

[0001] The present invention relates to aircraft tires, aircraft wheels, and aircraft landing gear. B ACKGROUND

[0002] Aircraft tires must be capable of withstanding the loads associated with aircraft operation, from the weight of the aircraft. It is desirable to make tires that are easy to maintain, and of reduced weight. Presently, to ensure the tires have suitable properties, the pressure of the gas inside the tires must be maintained at a high level of about 180-220PSI at ambient temperature. SUMMARY

[0003] A first aspect of the present invention provides an aircraft tire comprising an external wall, and an internal support structure located within the external wall, wherein the internal support structure is arranged such that the external wall is supported by the internal support structure and the internal support structure comprises a plurality of compartments.

[0004] The internal support structure may enable lower operational pressure of the tire to produce acceptable properties, such as ground footprint and loading capability, as the external wall may require less support from the pressure within the tire.

[0005] Lower pressure in the tire equates to smaller amount of gas needed in the tire. This decreases the time and costs associated with adding gas to the tires. The smaller amount of gas also may enable an overall weight saving. The inner support structure enables an improved tire footprint to be achieved with smaller amount of gas in the tire. The inner support structure enables the reduction of loads associated with spring resonance decoupling.

[0006] The aircraft tire according to the present invention is therefore easier and cheaper to maintain, and weights less than a conventional aircraft tire.

[0007] Optionally, the compartments are not in fluid communication with one another.

[0008] Optionally, at least some of the compartments are in fluid communication with one another.

[0009] Optionally, the internal support structure comprises a wall separating a pair of adjacent compartments, and wherein the wall comprises an orifice, through which the pair of adjacent compartments are in fluid communication with each other.

[0010] The orifice may be configured such that when a load is applied to one compartment of the pair of compartments, pressure equalisation between the pair of compartments is not instantaneous. Such a construction may permit the tire to perform locally as if a higher pressure of gas were present.

[0011] Optionally, each pair of adjacent compartments of the plurality of compartments comprises a respective wall separating the pair of adjacent compartments, and each wall comprises at least one orifice through which the respective pair of adjacent compartments are in fluid communication with each other. This enables a local pressure buildup on load application throughout the tire.

[0012] Optionally, the wall comprises a membrane of breathable membrane material extending across the orifice. This enables to restrict a flow of gas through the orifice to produce a tailored flow rate for the local pressure buildup effect described above.

[0013] Optionally, the internal support structure and the external wall are integrally formed. Such tires may be easy to produce, as the manufacture may comprise fewer steps, and install, as there are fewer components to install.

[0014] Optionally, the internal support structure is releasably attached inside the external wall. Such tire may be maintained easily when there are issues with either the external wall or the inner support structure. It may be more straightforward to manufacture the inner support structure and the external wall of different material with different properties in such a tire.

[0015] Optionally, the compartments are arranged in a repeating pattern, when viewed along an axis of rotation of the tire.

[0016] Optionally, the repeating pattern is at least one of a honeycomb pattern and a radially symmetric pattern. A radially symmetric pattern is symmetric about the axis of rotation of the tire, when viewed along the axis of rotation of the tire. A radially symmetric pattern may for example be a spoked pattern wherein walls extend from the external wall towards the axis of rotation.

[0017] Optionally, the repeating pattern is one of: triangular, square, rectangular, oval, circular, polygonal, or latticed.

[0018] Optionally, the support structure is formed from a foam material.

[0019] A second aspect of the present invention provides an aircraft tire internal support structure for supporting an external wall of an aircraft tire, the internal support structure comprising a plurality of compartments.

[0020] Optionally, the compartments are not in fluid communication with one another.

[0021] Optionally, at least some of the compartments are in fluid communication with one another.

[0022] Optionally, the internal support structure comprises a wall separating a pair of adjacent compartments, and wherein the wall comprises an orifice, through which the pair of adjacent compartments are in fluid communication with each other.

[0023] Optionally, each pair of adjacent compartments of the plurality of compartments comprises a respective wall separating the pair of adjacent compartments, and each wall comprises at least one orifice through which the respective pair of adjacent compartments are in fluid communication with each other.

[0024] Optionally, the wall comprises a membrane of breathable material extending across the orifice.

[0025] Optionally, the compartments are arranged in a repeating pattern, when viewed along an axis of rotation of the tire.

[0026] Optionally, the repeating pattern is at least one of a honeycomb pattern and a radially symmetric pattern.

[0027] Optionally, the support structure is formed of a foam material.

[0028] A third aspect of the present invention provides an aircraft wheel comprising a wheel hub and a tire mounted on the wheel hub, wherein the tire is an aircraft tire according to the first aspect or the tire comprises an aircraft tire internal support structure according to the second aspect.

[0029] A fourth aspect of the present invention provides an aircraft landing gear comprising a plurality of aircraft wheels according to the third aspect.

[0030] A fifth aspect of the present invention provides an aircraft comprising the landing gear of the fourth aspect.

[0031] Optional features of any one of the aspects of the present invention may be applied equally to any other one of the aspects of the present invention, where appropriate. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0033] Figure 1 shows a schematic representation of an aircraft according to a first example of the present invention;

[0034] Figure 2 shows a schematic cross-sectional side view of an aircraft wheel according to an example of the present invention;

[0035] Figure 3 shows a schematic cross-sectional front view of the aircraft wheel of Figure 2;

[0036] Figure 4 shows a partial view of an inner support structure of the aircraft wheel of Figure 2;

[0037] Figure 5 shows a schematic cross-sectional front view of an aircraft wheel according to a second example of the present invention;

[0038] Figure 6 shows a schematic front view of an inner support structure of the aircraft wheel of Figure 5;

[0039] Figure 7 shows a schematic cross-sectional side view of the inner support structure of Figure 6;

[0040] Figure 8 shows a schematic cross-sectional side view of an aircraft wheel according to a third example of the present invention;

[0041] Figure 9 shows a schematic cross-sectional side view of an aircraft wheel according to a fourth example of the present invention; and

[0042] Figure 10 shows a schematic cross-sectional side view of an aircraft wheel according to a fifth example of the present invention. DETAILED DESCRIPTION

[0043] An aircraft 100 according to an example of the present invention is shown in Figure 1. The aircraft 100 has a nose landing gear (NLG) and a pair of main landing gears (MLG). Each landing gear NLG and MLG has a pair of wheels 110, each of which has a tire according to an example of the present invention. In other example aircraft, only some of the wheels may have tires according to the present invention, and / or the aircraft may have a different configuration of wheels and landing gears. For example, in other examples, the tires according to the present invention may be especially beneficial and optimised for use in NGL, which requires lower load capacity, with the MLGs having conventional tires.

[0044] Figures 2 and 3 show schematic cross-sectional views of one of the wheels 110. The wheel 110 has a hub 210. A tire 200 is mounted on a rim 214 of the hub 210. The wheel 110 has an axis of rotation R, about which the wheel 110 is configured to rotate when the aircraft 100 is in motion on the ground.

[0045] The tire 200 has an external wall 202. The external wall 202 has a tread portion 218 which is in contact with the ground when the aircraft 100 is on the ground, and a side portion 216. The external wall 202 is formed from rubber. The tread portion 218 is located opposite the rim 214, and has a tread to provide traction with a surface the wheel 110 rolls on.

[0046] An internal support structure 204 is located within a space enclosed by the external wall 202 and the rim 214 of the hub 210. The internal support structure 204 defines a plurality of compartments 206. The compartments 206 are arranged such that, when viewed in a cross-sectional plane orthogonal to the rotation axis R, the compartments 206 are in a tessellating pattern. A first subset 207 of the compartments have a hexagonal cross-sectional shape in the cross-sectional plane, whilst a second subset 209 of the compartments, including those compartments 206 bounded partly by the external wall 202 and those compartments 206 bounded partly by the rim 214, have non-hexagonal cross-sectional shapes in the cross-sectional plane. Each compartment 206 of the first subset 207 is enclosed by cell walls 208 and vertical walls 212. The compartments 206 extend in a direction along axis R, separated by vertical walls 212. The cell and vertical walls 208, 212 are formed of the same rubber material as the external wall 202, and are integrally formed with the external wall 202.

[0047] Figure 4 shows a partial view of the inner support structure 204, showing three neighbouring compartments 206: a first compartment 206a, a second compartment 206b and a third compartment 206c. The first compartment 206a and the second compartment 206b share a first cell wall 208a. The first cell wall 208a has a first orifice 220a through which the first compartment 206a and the second compartment 206b are in fluid communication with one another.

[0048] Similarly, the second compartment 206b and the third compartment 206c share a second cell wall 208b, and the second cell wall 208b comprises a second orifice 220b. The third compartment 206c and the first compartment 206a share a third cell wall 208c, the third cell wall 208c comprising a third orifice 220c. All compartments 206 of both the first subset 207 and the second subset 209 of the inner support structure 204 are interlinked by orifices 220 in this manner.

[0049] The first, second and third orifices 220a, 220b and 220c comprise respective first, second and third membranes 222a-c of breathable material such that a fluid flow, such as flow of gas, is slowed to enable pressure to build up temporarily when a force, such as the weight of the aircraft 100 loading the tire 200 when landing and rolling on the ground, is applied to any of the first, second or third compartments 206a, 206b or 206c. The orifices 220a-c, in this example, are circular. The vertical walls 212 also comprise orifices (not shown) such that compartments 206 neighbouring in a direction of axis R are in fluid communication with one another. Therefore, an application of pressure onto the external wall 202 applies pressure to the compartments 206 closest to the external wall 202. While under pressure, for the duration of time necessary for the pressure to equalise among the neighbouring compartments 206, the compartments 206 closest to the external wall 202 experience a localised higher pressure. The compartments 206 may also be refilled with gas through the orifices 220, such as during a maintenance of the tire 200 including reinflation.

[0050] A second example tire 300 according is shown mounted on the rim 214 of the wheel 110 in Figure 5.

[0051] The second example tire 300 has an external wall 302. The external wall 302 has a tread portion 318 which is in contact with the ground when the aircraft is on the ground, and a side portion 316. The external wall 302 is formed from rubber. The tread portion 318 is located opposite the rim 214, and has a tread to provide traction with a surface the wheel rolls on.

[0052] An internal support structure 304 is located within a space enclosed by the external wall 302 and the rim 214 of the hub 210. The internal support structure 304 has been manufactured separately to the external wall 304. The internal support structure 304 is releasably attached inside the external wall 304. The internal support structure 304 is shown in isolation in Figures 6 and 7.

[0053] A separable inner support structure, such as the internal support structure 304, may be removed and repaired or replaced during the lifetime of a tire, and / or may be used in a second external wall while a first external wall is being maintained.

[0054] The internal support structure 304 defines a plurality of compartments 306. The compartments 306 are arranged such that, when viewed in a cross-sectional plane orthogonal to the rotation axis R, the compartments 306 are in a tessellating pattern. A first subset 307 of the compartments have a hexagonal cross-sectional shape in the cross-sectional plane, whilst a second subset 309 of the compartments, including those compartments 306 bounded partly by the external wall 302 and those compartments 306 bounded partly by the rim 214, have non-hexagonal cross-sectional shapes in the cross-sectional plane. Each compartment 306 of the first subset 207 is enclosed by cell walls 308 and by vertical walls 312.The cell and vertical walls 308, 312 are formed of a foam material.

[0055] The compartments 306 are in fluid communication with one another, in the manner described in relation to Figure 4 and inner support structure 204, except the membranes are omitted.

[0056] In alternative embodiments, some or all orifices interconnecting the compartments of the inner support structure are omitted. In an example without any orifices, gas is enclosed in the compartments during the manufacturing process. An example of such embodiment is shown in Figure 8, showing a third example tire 400 on a wheel 110. The third example tire 400 has the features of the tire 200 described with respect to Figures 2 and 3, but lacks the orifices and membranes described with respect to Figure 4. The third example tire 400 comprises compartments 406 which are not in fluid communication with one another. In other examples, there may be more than one orifice per side wall of each compartment, such as a series of circular perforations. In some examples, the orifices may have a different shape, such as an elongate slit shape.

[0057] In alternative embodiments, the walls of the inner support structure may comprise another a lightweight and compliant material, or a more rigid material to increase the support provided to the external wall.

[0058] In alternative embodiments, some or all of the walls (vertical and / or cell) of the inner support structure are omitted or configured in a different pattern than described, which may be regular or irregular, with uniform or non-uniform sizes of compartments. An example of an irregular structure with non-uniform compartment size is an expanded foam in which the pockets of the foam are the compartments.

[0059] An example of an alternative pattern is shown in Figure 9, showing a fourth example tire 500. The fourth example tire 500 is shown mounded on the rim 214 of the hub 210 of the wheel 110. The fourth example tire 500 comprises an external wall 502 and an internal structure defined by radial walls 508 and compartments 506 located in between the radial walls 508. The compartments 506 are separated by the radial walls 508, connecting from an area of the tire 500 near the rim 214 of the hub 210 to the external wall 502. The compartments 506 therefore extend from the rim 214 of the hub 210 to the external wall 502, and have a wedge-like shape, projected from the axis R.

[0060] A second example of an alternative pattern is shown in Figure 10, showing fifth example tire 600. The fifth example tire 600 is shown mounded on the rim 214 of the hub 210 of the wheel 110. The fifth example tire 600 comprises an external wall 602 and an internal structure defined by radial walls 608, circumferential walls 612 and compartments 606 enclosed by the radial walls 608 and the circumferential walls 612. The compartments 606 are separated by the radial walls 608, like in the previous example of Figure 9, and also by the circumferential walls 612. The circumferential walls 612 are concentric about the axis R. The compartments 606 are arranged in rows of three in a direction from the rim 214 of the hub 210 to an external wall 602 of the fifth example tire 600, with compartment 606 located at a same radial position collectively defining an annulus.

[0061] In the examples of Figures 9 and 10, the compartments 506,606 are not in fluid communication with one another, but may be so in other embodiments. In the examples of Figures 9 and 10, the pattern of compartments 506 and 606 are radially symmetric about the axis R.

[0062] In alternative embodiments, the wheel including the hub and the tire may be integrally formed, for example by additive manufacturing.

[0063] It is to be noted that the term “or” as used herein is to be interpreted to mean “and / or”, unless expressly stated otherwise.

Claims

1. An aircraft tire comprising an external wall, and an internal support structure located within the external wall, wherein the internal support structure is arranged such that the external wall is supported by the internal support structure and the internal support structure comprises a plurality of compartments.

2. The aircraft tire according to claim 1, wherein the compartments are not in fluid communication with one another.

3. The aircraft tire according to claim 1, wherein at least some of the compartments are in fluid communication with one another.

4. The aircraft tire according to claim 3, wherein the internal support structure comprises a wall separating a pair of adjacent compartments, and wherein the wall comprises an orifice, through which the pair of adjacent compartments are in fluid communication with each other.

5. The aircraft tire according to claim 4, wherein each pair of adj acent compartments of the plurality of compartments comprises a respective wall separating the pair of adjacent compartments, and each wall comprises at least one orifice through which the respective pair of adjacent compartments are in fluid communication with each other.

6. The aircraft tire according to any one of claims 4 or 5, wherein the wall comprises a membrane of breathable material extending across the orifice.

7. The aircraft tire according to any one of the preceding claims, wherein the internal support structure and the external wall are integrally formed.

8. The aircraft tire according to any one of claims 1 to 6, wherein the internal support structure is releasably attached inside the external wall.

9. The aircraft tire according to any one of the preceding claims, wherein the compartments are arranged in a repeating pattern, when viewed along an axis of rotation of the tire.

10. The aircraft tire according to claim 9, wherein the repeating pattern is at least one of a honeycomb pattern and a radially symmetric pattern.

11. The aircraft tire according to any one of the preceding claims, wherein the support structure is formed from a foam material.

12. An aircraft tire internal support structure for supporting an external wall of an aircraft tire, the internal support structure comprising a plurality of compartments.

13. The aircraft tire internal support structure according to claim 12, wherein the compartments are not in fluid communication with one another.

14. The aircraft tire internal support structure according to claim 12, wherein at least some of the compartments are in fluid communication with one another.

15. The aircraft tire internal support structure according to claim 14, wherein the internal support structure comprises a wall separating a pair of adjacent compartments, and wherein the wall comprises an orifice, through which the pair of adjacent compartments are in fluid communication with each other.

16. The aircraft tire internal support structure according to claim 15, wherein each pair of adjacent compartments of the plurality of compartments comprises a respective wall separating the pair of adjacent compartments, and each wall comprises at least one orifice through which the respective pair of adjacent compartments are in fluid communication with each other.

17. The aircraft tire internal support structure according to any one of claims 15 or 16, wherein the wall comprises a membrane of breathable material extending across the orifice.

18. The aircraft tire internal support structure according to any one of claims 12 to 17, wherein the compartments are arranged in a repeating pattern, when viewed along an axis of rotation of the tire.

19. The aircraft tire internal support structure according to claim 18, wherein the repeating pattern is at least one of a honeycomb pattern and a radially symmetric pattern.

20. The aircraft tire internal support structure according to any one of claims 12 to 19, wherein the support structure is formed of a foam material.

21. An aircraft wheel comprising a wheel hub and a tire mounted on the wheel hub, wherein the tire is an aircraft tire according to any one of claims 1 to 11 or the tire comprises the aircraft tire internal support structure of any one of claims 12 to 20.

22. An aircraft landing gear comprising an aircraft wheel according to claim 21.

23. An aircraft comprising the aircraft landing gear of claim 22.

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