Rod for braking aircraft wheel

Abstract

The invention relates to a rod (10) for a braking aircraft wheel (103, Figure 3), intended to be attached to the rim (104, Figure 3) of the wheel in order to rotate a brake rotor disc (106b, Figure 3). The rod comprises a substantially rectilinear body (11), at least one section (14) of which comprises two flanges (15) connected together by spokes (16) and intended to cooperate with the rotor disc. At least one bracket element (17) connects the free edge of each flange to the central part of the spoke.

Description

Technical Field

[0001] The present invention relates to the field of aviation and, in particular, to braking aircraft wheels. Background Art

[0002] Aircraft wheels are known to be mounted on landing gear and provided with corresponding brakes. Such brakes usually comprise stator discs alternately arranged with rotor discs, the rotor discs consisting of stator discs fixed to the inner periphery of the rim of the wheel. The alloy rod drives the rotation. The rod is received in a peripheral cutout of the rotor disk and extends in a direction substantially parallel to the axis of rotation of the wheel. The controlled pressure applied to the disk stack creates friction between the facing disks and thereby generates a braking torque that slows the rotation of the wheel.

[0003] The bars may be made integrally with the rim of the wheel, or they may be assembled thereto. Figure 1A Some prior art bars 1 have at one end 1a a cylindrical tail for engaging with holes made in a disk or "spoke" in the rim, and at the opposite end 1b a hole for receiving a screw screwed into a tapped hole in the rim. A titanium wedge 2 is inserted between the bar 1 and the rim, firstly to position the bar 1 in a direction parallel to the axis of rotation of the wheel, and secondly to help limit the transfer of heat between the brake disc and the rim, which could be harmful to the tire mounted on said rim.

[0004] like Figure 1B As shown, the rod 1 sometimes presents an H-shaped cross section, which is generally constant. Such a cross section is used to withstand the stresses caused by braking, in particular the shear and bending stresses caused by slowing down the rotor disk.

[0005] Such a rod is known from document FR-A-2 937 949, for example.

[0006] A braked aircraft wheel may have 7 to 11 rods 1, depending on the wheel size. For aircraft with two to six wheels per undercarriage and for rods 1 weighing 500 grams (g) to 800 grams, it can be seen that the rods significantly increase the overall weight of the wheel-brake assembly.

[0007] However, reducing aircraft weight has become a top priority for all aircraft manufacturers, especially since regulations have been encouraging them to do so. Specifically, environmental standards require reducing pollutant emissions, especially carbon dioxide (CO2) emissions. Summary of the invention

[0008] The object of the present invention is therefore to propose a lever for a braked aircraft wheel which makes it possible in particular to reduce the weight of the aircraft wheel and brake assembly without reducing the mechanical strength of said lever.

[0009] To this end, the invention provides a lever for a braked aircraft wheel, intended to be fitted to the rim of the wheel so as to drive in rotation a rotor brake disc. The lever comprises a substantially rectilinear body having at least one section comprising two wings connected together by a core and intended to cooperate with a rotor disc.

[0010] According to the invention, the bar comprises at least one bracket element connecting the free edge of each wing to the central portion of the core.

[0011] Such a support element enables the thickness of the wings and the core to be optimally determined, thereby reducing the overall weight of the bar without reducing its mechanical strength.

[0012] In a particular embodiment, the support element is a wall extending in the longitudinal direction of the rod between said free edge and the central portion of the core.

[0013] According to a particular feature, a portion of the body forms a fastener wedge for securing the rod to the rim.

[0014] Therefore, it is no longer necessary to provide an operation of adding the wedges while the rod is being put in place, thereby limiting the number of operations required to put the rod in place on the rim.

[0015] Advantageously, the wedge comprises a recess, whereby the overall weight of the rod is limited and the transfer of heat to the rim is also limited.

[0016] According to another particular feature, a portion of the body comprises a grid structure.

[0017] The present invention also provides a braked aircraft wheel comprising a rim having an inner periphery defining a space for receiving a rotor brake disc, and such a rod fastened to the rim so as to constrain the rotor brake disc to rotate with the rim.

[0018] The invention also provides a landing gear comprising at least one such wheel and an aircraft comprising such a landing gear.

[0019] The present invention also provides a method for manufacturing such a rod, which comprises at least one operation of manufacturing a rod body by additive manufacturing.

[0020] In a particular embodiment, the additive manufacturing operation is performed in such a way as to obtain the rod in a vertical position.

[0021] Alternatively, the additive manufacturing operation is carried out in such a way as to obtain the bar in a horizontal position and it comprises a step of making the lattice structure of the wall supporting the body of the bar.

[0022] Preferably, the additive manufacturing operation utilizes a laser beam to fuse the powder bed.

[0023] In certain cases, the powder is alloy powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention will be better understood from the following description, which is purely illustrative and not restrictive and should be read with reference to the accompanying drawings, in which:

[0025] - Figure 1A is a stereogram of a rod member of the prior art;

[0026] - Figure 1B yes Figure 1A The cross-sectional view of the rod shown in plane AA;

[0027] - Figure 2 is a side view of the aircraft including a landing gear provided with a brake wheel;

[0028] - Figure 3 yes Figure 2 an axial section through one of the brake wheels of the aircraft shown, the rim of which is fitted with a rod in a particular embodiment of the invention;

[0029] - Figure 4A yes Figure 3 A perspective view of the rod of the brake wheel shown;

[0030] - Figure 4B yes Figure 4A A cross-sectional view of the rod shown on plane a'-a';

[0031] - Figure 4C yes Figure 4A A detailed face view of a portion of the rod shown in ;

[0032] - Figure 4D yes Figure 4A a detailed rear view of a portion of the rod shown; and

[0033] - Figure 5 yes Figure 4A A cross-sectional view of a variation of the rod is shown, including a portion having a grid structure. DETAILED DESCRIPTION

[0034] Reference Figure 2 and 3The aircraft 100 of the present invention comprises a structure provided with landing gears 101. Each landing gear 101 comprises a leg, one end of which is hinged to the structure of the aircraft 100 and the opposite end carries an axle 102 on which a wheel 103 is rotatably mounted.

[0035] The wheel 103 comprises a rim 104 and spokes 105 connecting the rim 104 to a hub rotatably received on the axle 102 with the inner surface of the rim 104 extending towards the outer surface of the hub and cooperating with the hub to define a space for receiving a stack of brake discs. The stack comprises a stator disc 106a prevented from rotating relative to the legs of the landing gear and a rotor disc 106b comprising peripheral cutouts for receiving rods, generally referenced 10, which are fastened to the inner surface of the rim 104.

[0036] Reference Figure 4A , each lever 10 comprises a body 11 extending along a longitudinal axis X. The body 11 has a first end 11 a in the form of a cylindrical tail to be received in an orifice of the rim 104 extending parallel to the axis of rotation of the wheel 103 , and a second end 11 b comprising a hole 12 in radial direction for receiving a fastener screw for fastening the lever 10 to the rim 104 .

[0037] The body 11 also has two lateral bearing surfaces 13 extending parallel to the axis X, for cooperating with a fixture arranged in a peripheral notch of the rotor brake disc 106b. The two bearing surfaces 13 form a non-zero angle α so that, in use, they extend radially relative to the rim 104. A surface treatment of high velocity flame spraying (HVOF) is applied to the bearing surfaces 13 to obtain a suitable tribological behavior between the rod 10 and the fixture. All this is well known and is reviewed here only for information purposes.

[0038] between the first end and the second end, and if Figure 4B As shown, the body 11 comprises a section 14 of substantially constant cross section and symmetrical about the midplane of the body 11. The cross section is substantially H-shaped and the section 14 thus comprises two wings 15 whose inner faces are connected together by a core 16 and whose outer faces form the bearing surface 13. Each wing 15 has a bottom portion 15a and a top portion 15b, which extend on opposite sides of the core 16. In this example, the top portion 15b of the wing 15 presents a height greater than the height of the bottom portion 15a. In this example, the height of the top portion 15b of the wing 15 is substantially equal to four times the height of the bottom portion 15a of the wing 15. The distance between the free edges of the top portion 15b of the wing 15 is slightly greater than the distance between the free edges of the bottom portion 15a of the wing 15.

[0039] Furthermore, support elements 17 connect the free edge of the top portion 15b of the wing 15 to the central portion of the core 16. Each support element 17 has a wall having a planar area 17a extending between the central portion of the core 16 and a rounded area 17b connecting the planar area 17a to the free edge of the top portion 15b of one of the wings 15. The planar area 17a of each support element 17 forms an angle β, substantially equal to 45° in this example, with respect to the core 16. The support elements 17 serve to thwart any tendency of the wings 15 to deform or flip over while the lever 10 is in use, making it possible to optimize the thickness of the wings 15 and the core 16.

[0040] A portion of the end 11b of the body 11 is shaped to constitute a fastener wedge 18 for fastening the rod 10 to the rim 104. The wedge 18 is thus made integrally with the rod 10, and a hole 12 passes through its center so as to be able to pass a fastener screw for fastening the rod 10 to the rim 104. At its top portion, the wedge 18 has two planar bearing surfaces 18a extending in the same plane so as to cooperate with the planar surface of the rim 104. The two bearing surfaces 18a are symmetrically arranged on either side of the hole 12.

[0041] Reference Figure 4C and 4D , the wedge 18 is hollowed out by making two channels 18b extending substantially on either side of the hole 12 in a longitudinal direction relative to the rod. The channels 18b have several functions: they enable air to flow inside the wedge 18, in particular under the effect of a forced flow given by a brake cooling fan, and their presence limits the amount of material of the wedge 18, enabling heat to be transferred from the rotor brake disc 106b to the rim 104 by conduction.

[0042] Thus, channel 18 b significantly reduces the thermal conductivity of wedge 18 , thereby helping to significantly limit the temperature rise of rim 104 , particularly where bearing surface 18 a of wedge 18 bears against rim 104 , while maintaining the ability of wedge 18 to transmit braking torque to rim 104 .

[0043] The rod 10 is made in a vertical direction along its axis X by additive manufacturing, in particular by laser beam melting (LBM), on a metal powder bed. The rod 10 is then obtained in a vertical position. This method enables the rod 10 to be manufactured in a single operation based on a three-dimensional (3D) digital file of said rod 10. By selectively melting in a controlled atmosphere The rod 10 is constructed from alloy powder. The alloy powder is spread by a scraper to form a bed with a thickness ranging between 30 micrometers (μm) and 90 μm. A fiber laser beam is steered by a mirror to scan the bed so as to selectively melt the powder upstream of the area defined by the 3D digital file. For example, the laser beam can be an yttrium aluminum garnet (YAG) laser beam.

[0044] Compared to the rod 1, for the same fastener interface, the rod 10 enables a weight reduction of the rod and wedge assembly in the range of 15% to 20%. In addition, the mechanical strength of the rod, in particular the bending strength, is improved.

[0045] Of course, the invention is not limited to the embodiments described but covers any variant coming within the ambit of the invention as defined by the claims.

[0046] The main body 11 of the lever body 10 does not have to be integral with the wedge, but may have a bearing surface arranged to receive a wedge fitted on the lever.

[0047] In order to improve the rigidity of the rod 10 and also to enable the rod 10 to be manufactured by powder additive manufacturing in a way of obtaining the rod horizontally, a part of the main body 11 of the rod 10 may include a lattice structure 19, such as Figure 5 In other words, a hollowed-out lattice structure with a unit pattern, which can be, for example, a tetrahedron, is shown and serves as a wall for the support rods.

[0048] The support element 17 may be Figure 4B Shapes other than those shown.

[0049] Although in this example the rod 10 is produced by additive manufacturing, it may also be produced by other methods, for example by lost wax casting.

[0050] remove Besides alloy powders, other powders may also be used to manufacture the rod 10 , in particular depending on the operational requirements imposed on the rod (eg steel powder, . . . ).

Claims

1. A rod (10) for a braking aircraft wheel (103), intended to be fitted to a rim (104) of said wheel in order to drive a rotor brake disc (106b) in rotation, said rod comprising a substantially rectilinear body (11) having at least one section (14), said section (14) comprising two wings (15), said wings having: - inner surfaces connected together by a core (16) extending from the inner surface of one of the two wings to the inner surface of the other of the two wings; and - an outer surface, opposite to said inner surface and intended to cooperate with a rotor disk, The bar is characterized in that it comprises at least one bracket element (17) connecting the free edge of each wing to the central portion of the core, the free edge defining with the core a portion of the height of the wing.

2. The rod according to claim 1, characterized in that The support element (17) is a wall extending in the longitudinal direction of the bar between the free edge of the wing (15) and the central portion of the core (16).

3. The rod according to claim 1, characterized in that A portion of the body (11) forms a fastener wedge (18) for securing the rod to the rim (104).

4. The rod according to claim 3, characterized in that The portion of the body forming the wedge includes a recess (18b).

5. The rod according to any one of claims 1 to 4, characterized in that A portion of the body includes a grid structure.

6. A braked aircraft wheel (103) comprising a rim (104) having an inner periphery defining a space for receiving both a rotor brake disc (106b) and a rod (10) fastened to the rim so as to constrain the rotor brake disc to rotate with the rim, the wheel being characterized in that the rod is a rod according to any one of claims 1 to 5.

7. Landing gear (101) comprising at least one aircraft wheel (103) according to claim 6.

8. An aircraft (100) comprising a landing gear (101) according to claim 7.

9. A method for manufacturing a rod (10) according to any one of claims 1 to 5, comprising at least one operation of manufacturing the body of the rod by additive manufacturing.

10. The method according to claim 9, characterized in that The additive manufacturing operation is carried out in such a way as to obtain a rod in a vertical position.

11. The method according to claim 9, characterized in that The additive manufacturing operation is carried out in such a way as to obtain a bar in a horizontal position and comprises a step of making the lattice structure of the wall of the body supporting the bar.

12. The method according to any one of claims 9 to 11, characterized in that The additive manufacturing operation utilizes a laser beam to fuse materials onto a powder bed.

13. The method according to claim 12, characterized in that The powder is alloy powder.

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