BRAKED WHEEL FOR AN AIRCRAFT

Description

[0001] The present invention relates to the field of aeronautics and more particularly to the cooling of brakes equipping aircraft wheels. BACKGROUND OF THE INVENTION

[0002] An aircraft landing gear typically comprises a leg with one end connected to an aircraft structure and a second end fitted with a shaft or axle on which a wheel is mounted for pivoting. The wheel has a rim connected by a flange to a hub that receives the leg's shaft and, together with the rim, defines a space in which a stack of discs is arranged. These discs alternate between stator discs fixed relative to the shaft and rotor discs fixed relative to the rim. An actuator, such as a hydraulic cylinder, is arranged to exert a pressing force on the stack of discs via a hydraulic ring gear. The rim has two annular flanges or beadings between which a tire is mounted.

[0003] Each braking action performed by an aircraft pilot causes an increase in temperature of the aircraft's brake discs and their immediate surroundings. Safety considerations impose maximum temperature limits, for example: 204°C at the rim beads to preserve the tires and protect personnel who may need to work near the wheels; 120°C at the hydraulic ring to prevent the hydraulic fluid from decomposing into acidic sulfuric compounds that are harmful to the hydraulic circuit.

[0004] Furthermore, these same safety considerations lead to a ban on an aircraft taking off if the temperature of the brake discs exceeds 400°C. This latter limitation can directly impact the aircraft's turnaround time (known by the English acronym TAT, for "Turnaround Time"), since the pilot must absolutely wait for the brake disc temperature to drop below this threshold before taking off.

[0005] Various methods have been proposed to accelerate the cooling of brake discs and their immediate surroundings. One known method is to position an electric fan at the end of the axle to create airflow around the brake discs. However, establishing an efficient airflow between the rim and the discs is difficult, and excessive airflow can promote carbon oxidation of the discs. Furthermore, the fan generates noise and must be removed each time a wheel is handled (tire change, brake disc replacement, etc.), resulting in additional operations and therefore extra maintenance costs.

[0006] It has also been proposed to equip the brake, or the wheel, with cooling fins to dissipate the heat generated during braking. However, this method does not significantly reduce the cooling time of the discs, as the fins are not located on the hottest parts and geometric constraints limit the extent of the heat exchange surfaces offered by the fins with the ambient air.

[0007] Document DE3736508A1 shows an aircraft wheel according to the prior art. SUBJECT OF THE INVENTION

[0008] The invention therefore aims to improve the cooling of brake discs. SUMMARY OF THE INVENTION

[0009] To this end, the invention proposes an aircraft wheel according to claim 1.

[0010] The installation of such heat pipes makes it possible to capture the heat transmitted by the discs to the wheel and / or torsion tube, and to transport it to dissipate it in the ambient air, which leads to a reduction in waiting time at the stopover and the risk of damage to the tire.

[0011] In particular, the first tenons came from the material with the wheel.

[0012] In particular, the first tenons are bars attached to the wheel.

[0013] According to a particular feature of the invention, the heat pipe is tubular in shape and is implanted in a bore made in the tenon.

[0014] In particular, the heat pipe is held in the tenon by hydroforming.

[0015] In particular, a heat-conducting material is deposited between the heat pipe and the tenon.

[0016] According to another particular feature of the invention, the heat sink includes fins giving the end of the heat pipe an increased free surface area.

[0017] In particular, the fins are attached to the heat pipe by hydroforming.

[0018] According to another particular feature of the invention, the heat pipe extends parallel to the axis of rotation of the wheel.

[0019] According to another particular feature of the invention, the heat pipe is slightly inclined with respect to the axis of rotation of the wheel, the end of the heat pipe protruding from the tenon being further away from said axis of rotation than the portion of the heat pipe retained in the tenon and the heat pipe forming with the axis of rotation of the wheel an angle less than or equal to that defined by said axis of rotation and an external wall of the rim intended to receive a tire.

[0020] The invention also relates to an aircraft landing gear comprising at least one such wheel.

[0021] The invention also relates to an aircraft comprising at least one such landing gear. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The invention will be better understood in light of the following description, which is purely illustrative and not limiting, and should be read in conjunction with the single attached drawing: there figure 1 is a schematic exploded view of an aircraft landing gear equipped with a wheel (without its tire for clarity); the figure 2 is an axial cross-sectional view of a wheel according to the invention mounted on an axle of the aircraft landing gear illustrated in the figure 1 ; there figure 3 is a partial front view of the wheel illustrated in the figure 2 . DETAILED DESCRIPTION OF THE INVENTION

[0023] With reference to figures 1 And 2The invention relates to an aircraft comprising main landing gear, each leg having a 100 having a first end articulated to a structure of the aircraft and a second end provided with an axle 4, thus forming an axle hand. Each axle 4 is provided with a wheel 1 comprising a rim 2 connected by a disc to a hub 6 mounted to rotate on the axle 4 about an axis X by means of bearings 5 ​​carried by the hub 6. The rim 2 here comprises two half-rims 2a, 2b which are assembled by bolts 3 and which each have a bead such that a tire can be trapped between the beads.

[0024] The wheel 1 is equipped with a brake 10 comprising discs 11 received in an annular space delimited by the half-rim 2a and the hub 6. The stack of discs 11 is threaded onto a torsion tube 13 fixed to the axle hand by bolts and comprises stator discs 11a and rotor discs 11b. The brake 10 includes a support 15 for brake actuators 16 adapted to selectively apply a braking force to the stack of discs 11. The brake actuators 16 are hydraulic pistons.

[0025] The rotor discs 11b have an outer rim with notches, each of which receives a first tenon 7 made of material with the half-rim 2a to link the rotor discs 11b and the half-rim 2a in rotation. The stator discs 11a have an inner rim with notches, each receiving a second tenon 17 integral with the torsion tube 13. All of this is well known and is mentioned only to contextualize the invention.

[0026] In accordance with the particular embodiment of the invention illustrated in the figure 1 Each of the first tenons 7 of the rim 2 includes a non-through hole 7.1 designed to extend along the length of each first tenon 7. A tubular sintered heat pipe 20 is embedded in each of the holes 7.1. The heat pipe 20 extends parallel to the axis of rotation of the wheel opposite the edges of each disc 11, and only one end 20.1 of the heat pipe 20 protrudes outside the hole 7.1 and the half-rim 2a.

[0027] The heat pipe 20 is held in position within the tenon 7 by hydroforming (hot or cold). Thus, after being inserted into the tenon 7, the heat pipe 20 is plastically deformed, and its shape is locally determined by the bore 7.1, which acts as a die. This ensures close contact between the external surface of the heat pipe 20 and the wall of the bore 7.1.

[0028] In order to significantly reduce the contact resistance between the heat pipe 20 and the bore 7.1 of the tenon 7, a heat-conducting material such as a thermal adhesive, thermal paste, or a low-temperature expanding metal can be deposited between the heat pipe 20 and the walls of the tenon 7 defining the bore 7.1. It is understood that the contact is strengthened between the external surface of the heat pipe 20 and the wall of the bore 7.1, promoting heat transfer from one to the other by conduction.

[0029] At the end 20.1 of the heat pipe 20 are arranged a plurality of fins 21, each extending in a plane orthogonal to the axis X of rotation of the wheel 1. The fins 21 are here spaced from each other at regular intervals and constitute a heat sink giving the end 20.1 of the heat pipe 20 an increased free surface.

[0030] The fins 21 are here fixed to the heat pipe 20 by hydroforming after being threaded onto the end portion 20.1 of the heat pipe 20. Thus, the end portion 20.1 of the heat pipe 20 is plastically deformed and its diameter is locally determined by that of the orifices through which the fins 21 are inserted. The contact is thus reinforced between the external surface of the heat pipe 20 and the fins 21 promoting heat transfer from one to the other by conduction.

[0031] It is important that the fins 21 do not interfere with the rotation of the wheel 1 or the operation of the brake 10 and its braking actuators 16. The fins 21 must therefore extend to provide sufficient clearance from the brake 10 and the rim 2. The fins 21 here have an annular shape and extend around the support 15 ( figure 3 ).

[0032] The heat pipes 20, equipped with fins 21, capture the heat transmitted by the discs 11 to the rim half 2a and transfer it to the fins 21 to be dissipated by convection into the ambient air. Their placement in the studs 7 has the advantage of capturing the heat as close as possible to the discs 11, thus limiting its diffusion into the rim 2. This results in reduced waiting time during stops and a lower risk of tire damage.

[0033] It is understood that the heat pipes 20 extend substantially horizontally when the lander is in the extended position. The use of sintered heat pipes makes it possible to overcome the effects of gravity, as such heat pipes function in all positions relative to gravity, and particularly in the horizontal position as is the case with the heat pipes 20.

[0034] It should be noted that the installation of the heat pipes 20 in the studs 7 of the rim 2 is simple to implement, that their operation is entirely passive and therefore reliable, and that they can be installed on existing brakes.

[0035] Of course, the invention is not limited to the embodiment described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0036] Although the tenons 7 here come from the material with the half-rim 2a, the tenons 7 can also be bars added to the half-rim 2a and in which the heat pipes 20 are implanted.

[0037] Although the heat pipes 20 are here implanted in tenons attached to the half-rim 2a, they can also be implanted in the tenons 17 attached to the torsion tube 13 (or in bars attached to the torsion tube 13) to capture the heat from the discs 11 and limit its diffusion in said torsion tube 13.

[0038] Although here all the 7 tenons are equipped with a 20 heat pipe, only some of the 7 tenons can accommodate a 20 heat pipe.

[0039] Although here the end 20.1 of the heat pipes 20 is provided with fins 21, other types of heat sink can be used to dissipate the heat captured by the heat pipe 20.

[0040] The number and shape of the fins 21 may differ from those illustrated in the figure 1 .

[0041] Although the heat pipes 20 are positioned horizontally here, they can also be slightly inclined and form a non-zero angle α with the X-axis of rotation of the rim 2 to facilitate their operation against gravity. The heat pipes 20 can, in particular, be arranged in a cone. The protruding end 20.1 of the heat pipes 20 will thus be further from the X-axis than the portion of the heat pipes 20 held in position within the tenon 7. Specifically, the angle α will be substantially less than or equal to the angle β formed by the X-axis and an external wall 2c of the half-rim 2a that receives the tire.

[0042] The heat transfer fluids usable in heat pipes 20 are well known to those skilled in the art and depend on the operating temperature range. While water is suitable here for cooling a brake on an aircraft wheel, other fluids, particularly those with a higher heat capacity and / or corresponding to the operating temperature range of an aircraft brake, may be used.

[0043] Although the end 20.1 of the heat pipe 20 protrudes from the rim half 2a, the hole 7.1 can also be arranged so that the end of the heat pipe carrying the fins protrudes from the rim half 2b, particularly in the case of a one-piece rim. The fins are then arranged inside the rim half 2b.

[0044] Although here the heat pipe 20 is held in position in the tenon 7 by hydroforming, other methods of fixing can be used (gluing, bolting, additive manufacturing...).

Claims

1. An aircraft wheel (1) comprising a rim (2) fitted with rotor disks (11b) driven in rotation with the rim by means of first splines (7) secured to the rim and engaged in notches in the rotor disks, stator disks (11a) being interposed between the rotor disks and being provided with notches engaged on second splines secured to a brake torque tube (13) arranged to be fastened to an axle (4) carrying the wheel, the wheel comprising at least one heatpipe (20) having an end (20.1) projecting outside the wheel, and at least one heatsink (21) secured to said end of the heatpipe, the wheel being characterized in that the heatpipe is sintered and extends in at least one of the first and second splines parallel to a plane containing the axis of rotation of the wheel.

2. An aircraft wheel (1) according to claim 1, wherein the first splines (7) are integral with the wheel (1).

3. An aircraft wheel (1) according to claim 1, wherein the first splines (7) are bars fitted to the wheel (1).

4. An aircraft wheel (1) according to any preceding claim, wherein the heatpipe (20) is tubular in shape and is implanted in a bore (7.1) made in the spline (7).

5. An aircraft wheel (1) according to claim 4, wherein the heatpipe (20) is held in the spline (7) by hydroforming.

6. An aircraft wheel (1) according to claim 5, wherein a thermally conductive material is deposited between the heatpipe (20) and the spline (7).

7. An aircraft wheel (1) according to any preceding claim, wherein the heatsink comprises fins (21) imparting an increased free surface area to the end (20.1) of the heatpipe (20).

8. An aircraft wheel (1) according to claim 7, wherein the fins (21) are fastened to the heatpipe (20) by hydroforming.

9. An aircraft wheel (1) according to any preceding claim, wherein the heatpipe (20) extends parallel to the axis of rotation (X) of the wheel (1).

10. An aircraft wheel (1) according to any one of claims 1 to 8, wherein the heatpipe (20) slopes a little relative to the axis of rotation (X) of the wheel (1), the end (20.1) of the heatpipe that projects from the spline being further from said axis of rotation than the portion of the heatpipe held in the spline, and the heatpipe and the axis of rotation of the wheel forming between them an angle (α) that is less than or equal to the angle (β) defined by said axis of rotation and an outer wall (2c) of the wheel for receiving a tire.

11. An aircraft undercarriage including at least one wheel (1) according to any preceding claim.

12. An aircraft including at least one undercarriage according to claim 11.