Heat shield assembly

Abstract

The present invention relates to a heat shield assembly for braking aircraft wheels (1, FIG. 1), comprising a heat shield (10) and at least one spacer (20, 30), the at least one spacer comprising a body (21, 31) projecting from an outer surface of the heat shield and at least one generally cylindrical clamping element (22, 32) projecting from the body and perpendicularly passing through a teardrop-shaped opening (11, 11') in the heat shield. The clamping element includes an enlarged free end (22a, 32a) to form an annular groove (22c) with the body, the annular groove engaging the opening in the heat shield.

Description

Technical Field

[0001] The present invention relates to a heat shield for braking aircraft wheels, the heat shield being fitted with spacers to prevent any contact between the wheels and the heat shield, particularly when the wheels are rotating. Background Technology

[0002] Main aircraft landing gear wheels typically feature brakes consisting of a stack of discs, which includes rotor discs alternating with stator discs and housed within the wheel rim. During braking, the heat released due to friction between the discs can be considerable, and a rim with a heat shield inserted between the inward-facing surface of the rim and the discs is known to protect the rim and the tire carried by it from this heat inflow. The heat shield typically consists of multiple very thin metal plates separated by thin layers of air.

[0003] When the wheel rotates, the heat shield is subjected to large tangential and inertial forces, which causes contact between the heat shield and the wheel. This contact can be harmful to the rim, whose inward-facing surface is covered with paint, especially under repeated contact conditions. This repeated contact can lead to rim oxidation and thus reduce its mechanical properties.

[0004] It is known that heat shields are fitted with studs (also known as "spacers") made of polymer material to prevent any contact between the heat shield and the rim. Such studs typically include a base with an annular groove arranged to engage with the peripheral edge of a circular opening in the heat shield.

[0005] Although these studs were found to be effective, they were also found to be particularly difficult to insert into the openings of the heat shield, requiring the operator to use special tools to deform the base of the studs to allow them to be inserted into the openings. Furthermore, improper tooling could damage the studs and reduce the heat shield's holding force on them.

[0006] Document EP 2 687 742 discloses a heat shield including a keyhole-shaped opening into which a rectangular stud is inserted. While no special tool is required to insert the stud into the heat shield, its elongated shape prevents installation in limited spaces and makes point contact with the heat shield difficult. Furthermore, the long stud requires a large opening, which reduces the rigidity of the heat shield and diminishes the thermal protection it provides. Summary of the Invention

[0007] Therefore, the object of the present invention is to provide a heat shield assembly that can at least partially avoid the above-mentioned problems.

[0008] To this end, a heat shield assembly for braking aircraft wheels is provided, the assembly comprising a heat shield and at least one spacer. The spacer includes both a body projecting from an outward-facing surface of the heat shield and at least one generally cylindrical clamping element projecting from the body and perpendicularly passing through an opening in the heat shield. The clamping element has an enlarged free end for mating with the body to form an annular groove that engages with the peripheral edge of the opening in the heat shield.

[0009] According to the invention, the opening has the shape of a water droplet.

[0010] The shape of the opening allows the spacer to be placed on the heat shield without special tools. It also makes spacer placement easier and reduces maintenance time.

[0011] In a particular embodiment of the invention, the perimeter edge of the opening includes a circular portion of a larger diameter and a circular portion of a smaller diameter, which are connected together by two identical straight sections.

[0012] Specifically, the length of the opening is substantially equal to the diameter of the enlarged free end in the clamping element.

[0013] Specifically, the diameter of the larger diameter circular portion of the opening is approximately equal to the diameter of the bottom of the groove of the spacer.

[0014] Specifically, the thickness of the groove is greater than or equal to the thickness of the heat shield.

[0015] According to specific features, the body of the spacer includes a cylindrical portion having one end and an opposite end, a clamping element protruding from one end of the cylindrical portion along the axis of the cylindrical portion, and the opposite end of the cylindrical portion being free and covered by a spherical cap.

[0016] According to another specific feature, the heat shield includes two openings, and the spacer includes two clamping elements. The body of the spacer is elongated in shape and has two ends, each end having a corresponding clamping element that mates with a corresponding opening in the heat shield.

[0017] Specifically, the openings in the heat shield share a common longitudinal axis of symmetry and point towards each other. Attached Figure Description

[0018] The invention will be better understood from the following description, which is purely illustrative and non-limiting, and should be read with reference to the accompanying drawings, in which:

[0019] [ Figure 1 ] Figure 1This is a perspective view of a braked aircraft wheel equipped with a heat shield assembly in a specific embodiment of the present invention;

[0020] [ Figure 2 ] Figure 2 It is assembled into Figure 1 A perspective view of one of the heat shield components for the aircraft wheels shown;

[0021] [ Figure 3 ] Figure 3 yes Figure 2 Detailed view of the opening in the heat shield shown;

[0022] [ Figure 4 ] Figure 4 yes Figure 2 An axial sectional view of the spacer of the component shown;

[0023] [ Figure 5A ] Figure 5A It shows in Figure 4 The first step of placing the spacer in the opening shown;

[0024] [ Figure 5B ] Figure 5B The second step of placing the spacer is shown;

[0025] [ Figure 5C ] Figure 5C The third step of placing the spacer is shown;

[0026] [ Figure 5D ] Figure 5D The fourth step of placing the spacer is shown;

[0027] [ Figure 6 ] Figure 6 yes Figure 2 Detailed view of the two opposing openings in the heat shield shown; and

[0028] [ Figure 7 ] Figure 7 It shows the placement of Figure 6 A view of the spacer in the opening shown. Detailed Implementation

[0029] Reference Figure 1The present invention applies to an aircraft wheel 1, in which, in this example, the aircraft wheel comprises two half-rims 1a and 1b, which are connected together by bolts 2 to support a tire (not shown). The wheel 1 is provided with ball bearings for mounting it on an aircraft landing gear shaft to rotate about a rotation axis X. Half-rim 1a is hollow and receives a brake disc comprising a rotor disc and a stator disc. The rotor disc is driven to rotate about the rotation axis X of the wheel 1 by rods 3 fixed to an inwardly facing cylindrical surface of half-rim 1a. The stator disc engages with a braking torque receiving tube (not shown) that prevents the stator disc from rotating with the wheel 1. In this example, a heat shield consists of a plurality of identical heat shields 10, each extending between two rods, arranged between half-rim 1a and the disc to protect the wheel 1 from radiation emitted by the disc when hot. These are well known, and their review is solely for the purpose of positioning the present invention.

[0030] According to the invention, the heat shield 10 is equipped with spacers 20 and 30, which are made of polymer material and protrude from the inward-facing surface 10a of the heat shield 10 facing the half-rim 1a to prevent any contact between the heat shield 10 and the half-rim 1a.

[0031] Reference Figure 2 Two different types of spacers can be seen: spacer 20, which is typically cylindrical in shape and called a “short stud”, is used to provide potential point contact with the inward-facing surface of the half-rim 1a; and spacer 30, which is elongated in shape and called a “long stud”, is used to provide potential line contact with the inward-facing surface of the half-rim 1a.

[0032] The heat shield 10 is equipped with two long studs 30 and two short studs 20. Each long stud extends along a corresponding longitudinal edge of the heat shield 10. The short studs are arranged between the long studs 30, one of which is arranged between the proximal ends of the long studs 30 and the other is arranged between the distal ends of the long studs 30.

[0033] Each short stud 20 includes a body 21 that protrudes from an inward-facing surface of the heat shield 10 facing the half-rim 1a and extends along an axis Y orthogonal to said surface of the heat shield 10. Figure 4 The main body 21 includes a cylindrical portion 21a that forms a disk about the axis Y with a free surface covered by a spherical cap 21b so as to make point contact with the inward-facing surface of the half-rim 1a.

[0034] Each short stud 20 also includes a clamping element 22 extending along axis Y in a straight line with the body 21 and passing through the opening 11 in the heat shield 10. The clamping element 22 includes a retaining disc 22a about axis Y, projecting from the face of the heat shield facing the axis of rotation X of the wheel 1. The diameter of the retaining disc 22a is slightly smaller than the diameter of the body 21, and it is connected to the body 21 via a link disc 22b about the same axis as the retaining disc 22a and the body 21. The diameter of the link disc 22b is smaller than the diameters of the retaining disc 22a and the body 21 to mate with the retaining disc 22a and the body 21 to form an annular groove 22c that engages with the peripheral edge of the opening 11 in the heat shield 10. The thickness of the link disc 22b is greater than or equal to the thickness of the opening 11.

[0035] Reference Figure 3 and 4 The opening 11 is teardrop-shaped, with a first circular portion 11.1 centered on the axis Y, having a diameter substantially equal to that of the connecting disc 22b of the clamping element 22, and a second circular portion 11.2 having a diameter smaller than that of the first circular portion 11.1 and a thickness greater than or equal to that of the retaining disc 22a. For example, the diameter of the second circular portion 11.2 and the thickness of the retaining disc 22a are 3 mm and 2 mm, respectively. The circular portions 11.1 and 11.2 form the first and second ends of the opening 11, respectively, and they are connected together by a straight portion 11.3 of the same length. The end of the straight portion 11.3 is substantially tangent to the ends of the circular portions 11.1 and 11.2.

[0036] The opening 11 has a symmetrical axis S that passes through the middle portions of the circular portions 11.1 and 11.2 and intersects the axis Y. The distance between the middle portions of the circular portions is substantially equal to the diameter of the retaining disc 22a of the clamping element 22, and they define the length L of the opening 11.

[0037] In order to place the short stud 20 into the opening 11, the short stud 20 is initially tilted at an angle of approximately 45° relative to the inward-facing surface of the heat shield 10 facing the half-rim 1a. Figure 5A Then move upwards to the opening to insert the retaining disc 22a into the length L of the opening 11, such that the groove 22c engages with one of the end portions of the circular portion 11.1. Figure 5B Then, manual pressure is applied to the spherical portion 21b of the short stud 20 to deform the polymer material until the retaining disc 22a is fully through the opening 11 and the linking disc 22b mates with the opening 11. Figure 5C ).

[0038] Reference Figure 6 and 7Each long stud 30 includes an elongated body 31 that protrudes from the inward-facing surface of the heat shield 10 facing the half-rim 1a, the stud protruding along an axis Y' orthogonal to said surface of the heat shield 10. When viewed along axis Y', the body 31 is a rectangular shape with two semi-circular ends. The body has a raised free surface to provide line contact with the inward-facing surface of the half-rim 1a, and in this example, a straight-line contact.

[0039] At each end of its body 31, each long stud 30 also has a clamping element 32 that extends along axis Y' and passes through a corresponding opening 11' in the heat shield 10 that is identical to the opening 11. The clamping element 32 of the long stud 30 is the same as the clamping element 22 of the short stud 20, and each clamping element includes a retaining disc 32a and a connecting disc 32b that engages with the corresponding opening 11'.

[0040] It should be noted that the two openings 11' into which the long stud 30 is inserted are arranged opposite each other, pointing towards each other so that they present a common axis of symmetry S', and their smaller diameter circular portions face each other.

[0041] In order to place the long stud 30 on the heat shield 10, one of the clamping elements 32 is first inserted into one of the openings 11', and then the long stud 30 is pulled slightly so that the other clamping element 32 is placed into the other opening 11' by utilizing the deformation of the polymer material.

[0042] Of course, the present invention is not limited to the described embodiments, but covers any variations that fall within the scope of the invention as defined by the claims.

[0043] Spacers 20 and 30 can be made of any suitable material (silicone, synthetic polymer, natural rubber, synthetic rubber, etc.).

[0044] Spacers 20 and 30 can be manufactured by any suitable manufacturing method (injection molding, etc.).

[0045] Openings 11 and 11' can be cut directly into the heat shield 10 (by water spraying, laser cutting, etc.), or they can be formed by stamping.

[0046] The arrangement of studs 20 and 30 and openings 11 and 11' can differ. Figures 1 to 7 The layout shown.

[0047] The number of studs 20 and 30, the shape of their bodies 21 and 31, and their dimensions can be compared with... Figures 1 to 7 The difference is shown.

Claims

1. A heat shield assembly for braking an aircraft wheel (1), the assembly comprising a heat shield (10) and at least one spacer (20, 30), the at least one spacer comprising a body (21, 31) projecting outward from an outwardly facing surface of the heat shield and a generally cylindrical clamping element (22, 32) projecting from the body and perpendicularly passing through an opening (11, 11') in the heat shield, the clamping element having an enlarged free end (22a, 32a) for cooperating with the body to form an annular groove (22c), the annular groove engaging with the peripheral edge of the opening in the heat shield, the heat shield assembly being characterized in that the opening has a teardrop shape.

2. The heat insulation cover assembly according to claim 1, characterized in that, The perimeter edge of the opening (11, 11') includes a larger diameter circular portion (11.1) and a smaller diameter circular portion (11.2), which are connected together by two identical straight portions (11.3).

3. The heat insulation cover assembly according to claim 2, characterized in that, The length (L) of the opening (11, 11') is equal to the diameter of the enlarged free end (22a, 32a) of the clamping element (22, 32).

4. The heat insulation cover assembly according to claim 2 or 3, characterized in that, The diameter of the larger circular portion (11.1) of the opening (11) is equal to the diameter of the bottom of the groove (22c) in the spacer (20, 30).

5. The heat insulation cover assembly according to claim 2 or 3, characterized in that, The diameter of the smaller circular portion (11.2) of the opening (11) is greater than or equal to the thickness of the enlarged free end (22a) of the clamping element (32).

6. The heat insulation cover assembly according to claim 1, characterized in that, The thickness of the groove (22c) is greater than or equal to the thickness of the heat shield (10).

7. The heat insulation cover assembly according to claim 1, characterized in that, The body (21) of the spacer (20) includes a cylindrical portion (21a) having one end and an opposite end, the clamping element (22) protruding from the one end of the cylindrical portion along the axis of the cylindrical portion, and the opposite end of the cylindrical portion being free and covered by a spherical cap (21b).

8. The heat insulation cover assembly according to claim 1, characterized in that, The heat shield (10) includes two openings, and the spacer (30) includes two clamping elements. The body (31) of the spacer (30) is elongated and has two ends, each end having a corresponding clamping element (32) that mates with a corresponding opening (11') in the heat shield (10).

9. The heat insulation cover assembly according to claim 8, characterized in that, The openings (11') in the heat shield (10) present a common longitudinal axis of symmetry (S) and they point to each other.

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