Secondary strut for an aircraft landing gear

Abstract

The invention relates to a secondary strut (9) for an aircraft landing gear (2, 3) (1), comprising a first end intended to be articulated with respect to a main strut (8) of the landing gear (2, 3), a second end intended to be articulated with respect to a box (4) of the landing gear (2, 3), and a lower surface intended to be oriented towards at least one wheel (7) of the landing gear (2, 3), characterized in that said lower surface comprises a rounded area adapted to come into contact with a piece of a tire (16) of said wheel (7). Figure to be published with the abstract: Figure 3 [Fig. 3]

Description

Title of the invention: Secondary strut for an aircraft landing gear Technical field of the invention

[0001] [Fig.l] illustrates an aircraft 1, in particular an airplane, comprising two main landing gears or landing gears 2 and a nose landing gear 3. An example of a nose landing gear 3 is illustrated in [Fig.2] and an example of a main landing gear 2 is illustrated in [Fig.3].

[0002] The landing gears 2, 3 allow the aircraft 1 to operate on the ground, such as taxiing maneuvers (towing, taxiing, etc.), the takeoff run, the absorption of the landing impact, and the braking of the aircraft 1.

[0003] The landing gears 2, 3 illustrated in Figures 1 to 3 are retractable and can be retracted inside the aircraft 1 during the flight phases, so as to reduce aerodynamic resistance and drag. In the retracted position, the landing gears 2, 3 are housed in a housing provided in the fuselage or in the wings of the aircraft 1.

[0004] As illustrated in [Fig.l], the aircraft 1 may comprise two main landing gears 2, located behind the center of gravity of the aircraft 1, and a front landing gear 3, located at the front of the fuselage. Such a configuration is also referred to as a tricycle.

[0005] As can be seen in [Fig. 2], the front landing gear 3 comprises a box 4 intended to be articulated on the structure of the aircraft 1, a shock absorber comprising a piston or a rod 5, capable of sliding inside the box 4, the lower end of the rod 5 forming an axle 6 supporting wheels 7. The landing gear further comprises a main strut 8, also articulated on the structure of the aircraft 1, and a secondary strut 9 mounted between the main strut 8 and the box 4.

[0006] The landing gear 2, 3 can be moved from its retracted position to its deployed position by means of an actuator 10, such as a jack.

[0007] The secondary strut 9 has the function of locking the main strut 8 and the box 4 in the deployed position of the landing gear 2, 3. Furthermore, the secondary strut 9 can be equipped with a locking actuator 11, for example a jack, allowing the unlocking of the secondary strut 9, and therefore the movement of the landing gear 2, 3 towards its retracted position.

[0008] The front landing gear 3 is also equipped with a compass 12 making it possible to maintain the orientation of the rod, and therefore of the axle, relative to the box, and of the orientation means 15 of the axle 6, formed for example by one or more jack-type actuators. These orientation means 15 thus make it possible to steer the aircraft on the ground during the taxiing phases.

[0009] As illustrated in [Fig. 3], the main landing gear 2, 3 has a structure similar to that of the front landing gear. The main landing gear 2 differs from the front landing gear 3 in that the main strut 8 comprises two parts 13, 14 articulated relative to each other. The main landing gear 2 is also devoid of means for orienting the axle 15.

[0010] During the movement of the aircraft 1 on the ground, in particular during landing or takeoff, there is a risk of a tire 16 of one of the wheels 7 of the landing gear 2, 3 bursting. During the movement of the aircraft 1 on the ground, in particular during landing or takeoff, there is a risk of a tire 16 of one of the wheels 7 of the landing gear 2, 3 bursting. Such a burst can cause tire debris 17 to be projected onto the corresponding landing gear 2, 3. Some of the elements of the landing gear 2, 3, for example the box 4 or the main strut 8, have sufficient mechanical strength to avoid any risk of deterioration of this element by collision with the debris 17 of the tire 16. Conversely, there is a risk of deterioration of the secondary strut 9, of smaller section, when the debris 17 is projected onto the exposed surface 18 of said secondary strut.

[0011] [Fig. 4] schematically illustrates the case of a piece of debris 17 from a tire 16 coming into contact with the lower surface 18, which is generally flat, of the secondary strut 9. During contact between the debris 17 (dotted during contact) and the contact surface 18, a large part of the energy of the debris 17 is dissipated from the start of contact with said contact surface 18. Indeed, from the start of contact, the contact area is large.

[0012] In order to avoid deterioration of the locking function provided by this secondary brace 9, it is appropriate to limit or avoid the aforementioned risk of deterioration. Presentation of the invention

[0013] The invention aims to remedy this drawback, in a simple, reliable and inexpensive manner.

[0014] To this end, the invention relates to a secondary strut for an aircraft landing gear, comprising a first end intended to be articulated relative to a main strut of the landing gear, a second end intended to be articulated relative to a box of the landing gear, a lower surface intended to be turned in the direction of at least one wheel of the landing gear, characterized in that said lower surface comprises a rounded area capable of coming into contact with debris from a tire of said wheel.

[0015] The lower surface is defined as the surface extending along the extension axis of the secondary strut, from the first end to the second end, and facing towards the axle of the landing gear, i.e. downwards in the deployed position of the gear.

[0016] The rounded shape makes it possible to reduce the forces exerted on the secondary strut during an impact or collision with tire debris, by allowing cushioning and progressive contact between the debris and the exposed lower surface. This avoids the risk of damage to the secondary strut mentioned above.

[0017] Said rounded area is cylindrical, spherical or ellipsoidal in shape.

[0018] The rounded area extends over most of the lower surface.

[0019] A major part is defined as a part extending over more than 50 percent of the lower surface.

[0020] The lower surface has a first rounded area and a second rounded area, the two rounded areas having distinct radii of curvature.

[0021] The second rounded area may be of smaller radius of curvature than the first rounded area and may extend over a portion of the first rounded area.

[0022] The invention also comprises a landing gear comprising a box intended to be articulated on a structure of the aircraft, a shock absorber comprising a rod, capable of sliding inside the box, the lower end of the rod supporting at least one wheel comprising a tire, the landing gear comprising a main strut, intended to be articulated on the structure of the aircraft, characterized in that it comprises a secondary strut of the aforementioned type, said secondary strut being mounted between the main strut and the box, the lower surface of the secondary strut being turned towards the tire.

[0023] The invention also relates to an aircraft, characterized in that it comprises landing gear of the aforementioned type. Brief description of the figures

[0024] [Fig-1] is a perspective view of an aircraft equipped with two landing gears main and front axle,

[0025] [Fig.2] is a perspective view of the front axle,

[0026] [Fig.3] is a perspective view of the main landing gear,

[0027] [Fig.4] is a schematic view illustrating the projection of a tire debris facing a flat lower surface of a secondary strut of the landing gear, in accordance with the prior art,

[0028] [Fig.5] is a view illustrating the projection of a tire debris opposite of a curved lower surface of a secondary strut of a landing gear, in accordance with one embodiment of the invention,

[0029] [Fig.6] is a view corresponding to [Fig.5], illustrating the impact and deformation progressive debris on the curved lower surface of the secondary strut,

[0030] [Fig.7] is a view corresponding to [Fig.5], illustrating another form of sheave lization of the invention. Detailed description of the invention

[0031] Figures 5 and 6 illustrate a section of a secondary strut 9 according to an embodiment of the invention. The secondary strut 9 belongs to a landing gear 2, 3 comprising, as previously, a box 4 intended to be articulated on a structure of the aircraft 1, a shock absorber comprising a rod 5, capable of sliding inside the box 4, the lower end of the rod forming an axle 6 supporting at least one wheel 7 comprising a tire 16. The landing gear 2, 3 further comprises a main strut 8, intended to be articulated on the structure of the aircraft 1, and a secondary strut 9 mounted between the main strut 8 and the box 4, the lower surface 18 of the secondary strut 9 being turned towards the tire 16.

[0032] The secondary strut 9 comprises a first end articulated on the main strut 8 and a second end articulated on the box 4. Other architectures are of course possible. The lower surface 18 comprises a rounded zone 19 capable of coming into contact with debris 17 of a tire 16 of said wheel 7. The rounded zone 19 is cylindrical, spherical or ellipsoidal in shape. The rounded zone 19 extends over the majority of the lower surface 18, that is to say over more than 50 percent of the lower surface 18.

[0033] The lower surface 18 is defined as the surface extending along the extension axis of the secondary strut 9, from the first end to the second end, and facing in the direction of the axle 6 of the landing gear 2, 3, i.e. downwards in the deployed position of the gear 2, 3.

[0034] The rounded shape makes it possible to reduce the forces exerted on the secondary strut 9 during an impact or collision with debris 17 of a tire 16, by allowing cushioning and progressive contact between the debris 17 and the exposed lower surface 18. This avoids the risk of damage to the secondary strut 9, mentioned above.

[0035] Indeed, as illustrated in [Fig.6], the debris 17 gradually comes, over time (the different successive positions of the debris are illustrated in dotted lines), into contact with an increasingly large part of the surface in lower 18, due to the rounded shape of the corresponding zone 18 and the deformation of the debris 17, the debris 17 being for example made of elastomer. This progressive contact makes it possible to gradually absorb the energy of the impact between the debris 17 and the secondary strut 9 and, thus, to avoid damage to the secondary strut 9.

[0036] [Fig.7] illustrates another embodiment of the invention, in which the lower surface 18 comprises a first rounded zone 19 and a second rounded zone 20, the two rounded zones 19, 20 having distinct radii of curvature.

[0037] The second rounded zone 20 has a smaller radius of curvature than the radius of curvature of the first rounded zone 19 and extends over a portion of the first rounded zone 19.

[0038] As previously, such an embodiment makes it possible to gradually absorb the shock due to a collision of a piece of debris 17 of a tire 16 on the lower surface 18 of the secondary strut 9.

Claims

Claims

1. Secondary strut (9) for a landing gear (2, 3) of an aircraft (1), comprising a first end intended to be articulated relative to a strut (8) of the landing gear (2, 3), a second end intended to be articulated relative to a box (4) of the landing gear (2, 3), a lower surface (18) intended to be turned towards at least one wheel (7) of the landing gear (2, 3), characterized in that said lower surface (18) comprises a rounded zone (19) capable of coming into contact with a debris (17) of a tire (16) of said wheel (7), the lower surface (18) comprises a first rounded zone (19) and a second rounded zone (20) extending projecting from the first rounded zone (19), the two rounded zones (19, 20) having distinct radii of curvature.

2. Secondary strut (9) according to claim 1, characterized in that said rounded zone (19) is cylindrical, spherical or ellipsoidal in shape.

3. Secondary strut (9) according to claim 1 or 2, characterized in that the rounded area (19) extends over the major part of the lower surface (18).

4. Landing gear (2, 3) comprising a box (4) intended to be articulated on a structure of the aircraft (1), a shock absorber comprising a rod (5), capable of sliding inside the box (4), the lower end of the rod (5) supporting at least one wheel (7) comprising a tire (16), the landing gear (2, 3) comprising a main strut (8), intended to be articulated on the structure of the aircraft (1), characterized in that it comprises a secondary strut (9) according to one of claims 1 to 3, said secondary strut (9) being mounted between the main strut (8) and the box (4), the lower surface (18) of the secondary strut (9) being turned towards the tire (16).

5. Aircraft (1), characterized in that it comprises a landing gear (2, 3) according to claim 4.

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