Landing gear of a vertical landing vehicle incorporating a lattice-structured crushable device

Abstract

The invention relates to a landing gear (100) of a vertical landing vehicle (500), the landing gear comprising a damping assembly comprising: - a linear damper (20) comprising a piston rod (21) slidably mounted inside a cylindrical body (22); - a crushable device (30) comprising at least one deformable element (31), characterised in that the crushable device (30) is arranged outside the cylindrical body (22), and is coupled to the linear damper (20) in a series or parallel configuration, and in that each deformable element (31) is obtained by additive manufacturing and comprises a lattice structure (32).

Description

[0001] Landing gear of a vertical landing vehicle incorporating a crushing device based on lattice structures

[0002] Technical field of the invention

[0003] The present invention falls within the field of vertical landing vehicles. The invention relates to a landing gear for a vertical landing vehicle. More particularly, the landing gear according to the invention incorporates a crushing device based on lattice structures.

[0004] Previous technique

[0005] Vertical landing aerospace vehicles such as airplanes, helicopters, vertical take-off and landing (VTOL) aircraft, reusable space launchers, space vehicles... have been developing more and more in recent years, whether in the context of military or civil applications.

[0006] These vertical landing aerospace vehicles typically have landing gear with two main functions: to absorb the shock during landing and to ensure the vehicle's stability after impact. Shock absorption is achieved by a specific device designed to absorb the energy resulting from the impact with the ground during vertical landing, without compromising the vehicle's stability after impact.

[0007] A shock absorption device is generally designed to absorb shock energy under nominal conditions, and to absorb additional shock energy under extreme conditions.

[0008] A shock absorption device can be an active or passive mechanical system, generally consisting of a hydraulic or pneumatic cylinder, or other linear actuator, and / or a component made of a crushable, honeycomb-type material, usually aluminum. This component may be directly encapsulated within the cylinder body, making its inspection complex after the vehicle lands. Furthermore, the crushable, honeycomb-type material expands radially during compression, becoming very difficult to remove from the cylinder body.

[0009] Furthermore, devices containing a part made of a crushable material undergo irreversible deformation and must therefore be replaced before the vehicle can be put back into operation. Their replacement necessarily involves either dismantling and reassembling the cylinders or replacing the cylinders themselves.

[0010] Finally, the design of these devices, based on crushable honeycomb materials, is particularly constrained by the available materials and the dimensions of the cylinder body that houses them. Achieving the required performance can ultimately lead to significant weight increases.

[0011] There is therefore a need for a landing gear with improved absorption capacity during the landing phase, while limiting its mass, and easier refurbishment.

[0012] Presentation of the invention

[0013] The present invention aims to remedy the aforementioned drawbacks.

[0014] To this end, the present invention proposes a landing gear for a vertical landing vehicle, said landing gear comprising a damping assembly including:

[0015] - a linear damper comprising a piston rod mounted to slide within a cylindrical body,

[0016] - a crushing device comprising at least one element configured to absorb energy by crushing, called a deformable element.

[0017] The crushing device is arranged outside the cylindrical body, and coupled to the linear damper in a series or parallel configuration.

[0018] Each deformable element is obtained by additive manufacturing and features a lattice structure.

[0019] Lattice structure refers to a lattice structure corresponding to an assembly of interwoven strands assembled to form a rigid and porous structure, or a structure corresponding to an assembly of interwoven surface elements assembled to form a rigid and porous structure.

[0020] Additive manufacturing makes it possible to create lattice structures that meet the desired constraints.

[0021] A landing gear according to the invention thus makes it possible to obtain an improved absorption capacity during the landing phase, while limiting its mass.

[0022] The crushing device can be sized to be stressed either during a vertical landing under nominal conditions, or during a vertical landing under extreme conditions.

[0023] Since the crushing device is positioned outside the cylindrical body of the linear damper, the crushing device is advantageously no longer constrained by the dimensions of the cylindrical body of the linear damper.

[0024] Furthermore, this makes it more accessible to an operator for easier replacement. According to particular embodiments of the invention, the landing gear also meets the following characteristics, implemented separately or in each of their technically operative combinations.

[0025] In particular embodiments of the invention, the landing gear comprises a primary structure including one or more primary connecting rods. The compression device is coupled to the linear damper in a series configuration. The compression device and the linear damper are integrated into the same primary connecting rod, or the compression device is integrated into a primary connecting rod connected in series with another primary connecting rod incorporating the linear damper. The compression device is assembled reversibly.

[0026] In particular embodiments of the invention, the landing gear comprises a primary structure including one or more primary connecting rods. The compression device is coupled to the linear damper in a parallel configuration. The compression device is integrated into a primary connecting rod connected in parallel with another primary connecting rod incorporating the linear damper. The compression device is assembled reversibly.

[0027] In particular embodiments of the invention, the landing gear comprises a primary structure including one or more primary connecting rods. The compression device is coupled to the linear damper in a parallel configuration. The compression device and the linear damper are integrated into the same primary connecting rod. The piston rod includes a thrust element mounted outside the cylindrical body. The compression device is arranged between the cylindrical body and the thrust element of the piston rod. The compression device is assembled reversibly.

[0028] In particular embodiments of the invention, the crushing device comprises a plurality of deformable elements joined together, the deformable elements being identical or not.

[0029] In particular embodiments of the invention, the lattice structure of a deformable element has an overall cylindrical shape, preferably with a circular cross-section.

[0030] In particular embodiments of the invention, a deformable element comprises an external wall surrounding the lattice structure.

[0031] In particular embodiments of the invention, a deformable element comprises, along the entire length of the lattice structure, a hollow internal cylindrical space without a lattice structure.

[0032] In particular embodiments of the invention, a deformable element comprises, along the entire length of the lattice structure, an internal wall delimiting the hollow internal cylindrical space.

[0033] The invention also relates to a vertical landing vehicle comprising a structural frame and at least one landing gear exhibiting one or more of the characteristics described above and / or below. Each landing gear is connected to the structural frame by a fastening element.

[0034] Brief description of the figures

[0035] The invention will be better understood upon reading the following description, given by way of non-limiting example, and made with reference to the figures which represent:

[0036] Figure 1 illustrates a perspective view of an example of a vehicle's landing gear,

[0037] Figure 2 illustrates a perspective view of an example of the landing gear of another vehicle,

[0038] Figure 3 illustrates representations of different forms of implementation of deformable elements cut at 1 / 4,

[0039] Figure 4 illustrates cross-sectional views of different shapes of deformable elements. Figure 5 illustrates an example of a series assembly of a linear damper and a deformable element.

[0040] Figure 6 illustrates an example of a parallel assembly of a linear damper and a deformable element,

[0041] Figure 7 illustrates another example of a parallel assembly of a linear damper and a deformable element,

[0042] Figure 8 illustrates another example of a parallel assembly of a linear damper and a deformable element. Description of embodiments

[0043] The present invention relates to a landing gear 100 of a vertical landing vehicle.

[0044] In the remainder of the description, the vertical landing vehicle will simply be referred to as vehicle 500.

[0045] The vertical landing vehicle is an aerospace vehicle.

[0046] The term "aerospace vehicle" refers to both space vehicles (such as reusable launch vehicles or space landers) and aeronautical vehicles (such as airplanes, helicopters, drones, vertical take-off and landing (VTOL) aircraft).

[0047] Figures 1 and 2 illustrate a perspective view of two examples of landing gear 100 of a vehicle 500.

[0048] In the non-limiting example of Figures 1 and 2, the vehicle is a reusable space launcher.

[0049] Although the 500 vehicle is shown in Figures 1 and 2 as a reusable space launcher, the invention can be applied to any other vertical landing vehicle, including those listed above, without departing from the scope of the invention.

[0050] As shown in Figures 1 and 2, the vehicle 500 comprises a structural frame 510 and one or more landing gear 100. Only one landing gear is shown in Figures 1 and 2. Each landing gear 100 is configured to be attached to the structural frame 510 of the vehicle 500 by a fastening member 520.

[0051] In the following description, only landing gear 100 is described. It is clear that the description that follows applies primarily to all landing gear configurations of vehicle 500.

[0052] The landing gear 100 comprises a primary structure 110. The primary structure 110 comprises one or more assembled primary connecting rods 140.

[0053] In the example in Figure 1, the landing gear 100 has a primary structure with two primary connecting rods 140 assembled in series.

[0054] In the example of Figure 2, the landing gear 100 comprises a primary structure with a primary connecting rod 140. The primary structure 110 has two ends 120, 130. A first end 120 is preferably intended to be connected, directly or indirectly, to the structural framework 510 of the vehicle 500. A second end 130 is preferably intended to be connected to a support piece 550 intended to rest on the ground.

[0055] In one embodiment, the primary structure 110 is directly connected to the structural frame 510 of the vehicle 500, at its first end 120, by the fastening member 520, for example by a joint. The joint may be a pivot joint or a ball joint.

[0056] The landing gear 100 may include other bars, called secondary bars 540, connecting the structural frame 510 of the vehicle 500 to the ground or connecting the structural frame 510 of the vehicle 500 to the primary structure 110, to stabilize the primary structure 110 and thus reinforce the landing gear 100. Each secondary bar 540 has one or more connecting rods assembled.

[0057] The landing gear 100 also includes a damping assembly. This damping assembly is configured to absorb the energy resulting from the impact with the ground during vertical landing, without compromising the stability of the vehicle 500 after the impact. The damping assembly is configured to absorb both the energy of impacts under nominal conditions and the additional energy of impacts under extreme conditions.

[0058] The damping assembly includes a linear damper 20 and a crushing device 30, as illustrated in Figures 1 and 2.

[0059] The linear damper 20 is preferably configured to be stressed during a vertical landing of vehicle 500 under nominal conditions and to contribute to the stabilization of vehicle 500 after landing. The linear damper 20 is thus sized to absorb all or part of the impact energy during a vertical landing of vehicle 500 under nominal conditions, depending on the specific operational constraints of the vehicle's context. The residual energy is absorbed by irreversible deformation of the crushing device 30.

[0060] The linear damper 20 is integrated into one of the primary connecting rods 140 of the primary structure 110 of the landing gear 100. The linear damper 20 comprises a piston rod 21 and a cylindrical body 22, visible in Figure 2. The linear damper 20 is arranged in the primary structure 110 of the landing gear 100 such that the piston rod 21 moves along a longitudinal axis A of the primary structure 110. The piston rod 21 is slidably mounted within the cylindrical body 22. In other words, the piston rod 21 moves axially within the cylindrical body 22.

[0061] The linear damper 20 can be, for example, a hydraulic cylinder or a pneumatic cylinder. Only the fluid to be compressed differs.

[0062] The piston rod 21 has a first end 211 located outside the cylindrical body 22. The piston rod 21 has a second end 212 (figures 6 to 8), opposite the first end 211, located in the cylindrical body 22.

[0063] The cylindrical body 22 has a first end 221 located on the side of the first end of the piston rod 21. The cylindrical body 22 has a second end 222 opposite the first end 221.

[0064] In a non-limiting embodiment, the first end 211 of the piston rod 21 is located in a primary connecting rod 140 of the primary structure 110, on the side of the first end 120 of the primary structure 110 and can be connected, directly (Figure 2) or indirectly, to the structural frame 510 of the vehicle 500. The second end 222 of the cylindrical body 22 is located in the same primary connecting rod 140 of the primary structure 110, on the side of the second end 130 of the primary structure 110 and can be connected, directly (Figure 2) or indirectly, to the support piece 550 intended to rest on the ground.

[0065] In another non-limiting embodiment (not shown in the figures), conversely, the first end 211 of the piston rod 21 is located in a primary connecting rod 140 of the primary structure 110, on the side of the second end 130 of the primary structure 110. The second end 222 of the cylindrical body 22 is located in the same primary connecting rod 140 of the primary structure 110, on the side of the first end 120 of the primary structure 110, and can be connected, directly or indirectly, to the structural frame 510 of the vehicle 500.

[0066] As described previously, the damping assembly includes a crushing device 30.

[0067] The crushing device 30 is preferably configured to withstand a more forceful vertical landing than a normal vertical landing. The crushing device 30 is then sized to absorb the energy of an impact following a non-normal (or extreme) vertical landing of vehicle 500. Alternatively, the crushing device 30 can also be configured to withstand a normal vertical landing. In this case, the crushing device 30 is sized to absorb a larger portion of the impact energy following a normal vertical landing, thus reducing the stress on the linear damper.

[0068] The crushing device 30 can be integrated into one of the primary connecting rods 140 of the primary structure 110 of the landing gear 100.

[0069] The crushing device 30 can be integrated into the same primary connecting rod 140 of the landing gear primary structure 110 as the one incorporating the linear damper. Alternatively, the crushing device 30 can be integrated into a different primary connecting rod 140 of the landing gear primary structure 110 than the primary connecting rod incorporating the linear damper 20.

[0070] According to the invention, the crushing device 30 is arranged outside the cylindrical body 22 of the linear damper 20. As such, the crushing device 30 is dimensioned not only to absorb the energy of the shock in compression along its axis but also to support the other stresses supported by the primary connecting rod into which it is integrated (moments, overall buckling stability).

[0071] The crushing device 30 comprises one or more elements configured to absorb energy by crushing, called deformable elements 31.

[0072] In the example of the figures, only a deformable element 31 is represented.

[0073] Each deformable element 31 comprises a lattice structure 32. In the following description, a lattice structure is understood to mean a lattice structure corresponding to an assembly of interwoven strands assembled to form a rigid and porous structure, or a structure corresponding to an assembly of interwoven surface elements assembled to form a rigid and porous structure. It is clear from the description that the lattice structure 32 is a three-dimensional structure.

[0074] Each deformable element 31 is obtained by additive manufacturing.

[0075] Each deformable element 31 is preferably made of a metallic material, such as titanium, steel, aluminum, or a nickel-based alloy, or of a polymer material, such as a thermoplastic. Each deformable element 31 is configured to deform irreversibly. As illustrated in the various views of Figure 3, to meet requirements in terms of stiffness, irreversible crushing force, maximum crushing distance, absorbed energy, and any other performance indicator, the lattice structure 32 of the deformable element 31 preferably has an overall cylindrical shape.

[0076] The diameter of the lattice structure 32 of the deformable element 31 may be different from that of the primary connecting rod 140 incorporating said deformable element.

[0077] To eliminate instability phenomena, the lattice structure 32 of the deformable element 31 is preferably of circular cross-section.

[0078] In one embodiment of a deformable element 31, the lattice structure 32 can extend throughout the entire internal volume of the deformable element 31. This embodiment is illustrated for example in the illustration of view a) of Figure 3 and in the schematic representation of view a) in section of Figure 4.

[0079] In one embodiment of a deformable element 31, said deformable element may comprise, along the entire length of the lattice structure 32, a hollow internal cylindrical space 36, without a lattice structure. The lattice structure 32 thus extends partially into the internal volume of the deformable element 31. This embodiment is illustrated, for example, in the illustration of view b) of Figure 3 and in the schematic representation of view b) in section of Figure 4.

[0080] In one embodiment of a deformable element 31, said deformable element may include an outer wall 33 surrounding the lattice structure 32 along its entire length. Preferably, the outer wall 33 is a corrugated wall. This embodiment is illustrated, for example, in the illustrations of views c) and d) of Figure 3 and in the schematic representation of cross-sectional view a) of Figure 4. The outer wall 33 and the lattice structure 32 are produced together during additive manufacturing.

[0081] In one embodiment of a deformable element 31, where said deformable element has a hollow internal cylindrical space 36 along the entire length of the lattice structure 32, said deformable element may have an internal wall 34 delimiting the hollow internal cylindrical space 36 along the entire length of the lattice structure 32. This embodiment is illustrated, for example, in view e) of Figure 3. Preferably, the internal wall 34 is a corrugated wall. The internal wall 34 and the lattice structure 32 are produced together during additive manufacturing.

[0082] In one embodiment of a deformable element 31, where the deformable element 31 has a hollow internal cylindrical space 36 along the entire length of the lattice structure, said deformable element may have an external wall 33 and an internal wall 34, said internal and external walls 33, 34 together delimiting the lattice structure 32 along its entire length. This embodiment is illustrated, for example, in view f) of Figure 3 and in the schematic representations of cross-sectional views b) and c) of Figure 4. Preferably, the external wall 33 and / or the internal wall 34 is / are a corrugated wall. The internal wall 34, the external wall 33, and the lattice structure 32 are produced together during additive manufacturing.

[0083] The embodiments of the deformable element 31 listed below can be made separately or can be combined, provided that the combinations are technically feasible.

[0084] In one embodiment of the deformable element 31, where the deformable element 31 has, along the entire length of the lattice structure, a hollow internal cylindrical space 36, said deformable element may include an insert 37, particularly to reinforce said lattice structure. The insert 37 is preferably arranged transversely, that is, arranged perpendicular to the direction along which the deformable element 31 extends longitudinally. This embodiment is illustrated, for example, in the schematic representation of the cross-sectional view (c) of Figure 4.

[0085] When the crushing device 30 comprises a plurality of deformable elements 31, said deformable elements are preferably placed side by side, two by two. The deformable elements 31 may or may not be identical.

[0086] The crushing device 30 is configured for reversible assembly. In other words, the crushing device 30 is configured to be removably connected to one of the landing gear elements 100.

[0087] In one embodiment, as illustrated in the schematic representations of views a) to c) in section of figure 4, the deformable element 31 has, at each of its longitudinal ends, a fixing interface 35.

[0088] In one embodiment, to facilitate the mounting of the deformable element 31 on one of the landing gear elements 100 or to another deformable element 31, the fixing interface 35 may have one or more through holes, for example threaded, (not shown in the figures) intended to receive each one fixing screw 60. In the example illustrated in Figure 5, two fixing screws 60 are visible for each fixing interface 35 of the deformable element 31.

[0089] The fixing interfaces 35 and the lattice structure 32 of a deformable element 31, and where applicable the inner wall, the outer wall, are made together during additive manufacturing.

[0090] As described previously, the crushing device 30 is configured to be stressed either during a vertical landing under nominal conditions or during a vertical landing under extreme conditions.

[0091] The length of the lattice structure 32 of each deformable element 31, as well as the external diameter, material, pattern and density of the lattice structure 32, are preferably chosen, in combination with each other, so that the crushing device 30 is able to absorb the energy of an impact following a vertical landing under non-nominal conditions of the vehicle 500 or so that the crushing device 30 is able to absorb a larger part of the energy of an impact following a vertical landing under nominal conditions of the vehicle 500.

[0092] It is within the competence of a person skilled in the art to determine the combinations of length, diameter, material, pattern and density of the lattice structure that will achieve the desired performance, or any substantially equivalent performance required.

[0093] According to the invention, the crushing device 30 is advantageously coupled to the linear damper 20 either in a series configuration or in a parallel configuration.

[0094] In a first version, the crushing device 30 is coupled to the linear damper 20 in a series configuration.

[0095] As described previously, the crushing device 30 is integrated into one of the primary connecting rods of the primary structure 110 of the landing gear 100. The crushing device 30 can be integrated either into the same primary connecting rod 140 of the primary structure 110 as the one integrating the linear damper 20, or integrated into a primary connecting rod 140 of the primary structure 110 other than the primary connecting rod integrating the linear damper 20. In this first version, the series assembly of the crushing device 30 with the linear damper 20 can be carried out either in the same primary connecting rod 140, or in two different primary connecting rods connected in series with each other of the primary structure 110 (as illustrated in Figure 1).

[0096] The linear damper 20 is assembled in series with a connecting tube 40. The connecting tube 40 is thus either a component of the same primary connecting rod 140 or a component of a separate primary connecting rod 140. The connecting tube 40 is connected to the piston rod 21. More precisely, the connecting tube 40 is connected to the first end of the piston rod 21.

[0097] Thus, when the piston rod 21 is located on the side of the first end 120 of the primary structure 110, the connecting tube 40 is interposed between the first end 120 of the primary structure 110 and the piston rod 21, more precisely the first end 211 of the piston rod 21.

[0098] Conversely, when the piston rod 21 is located on the side of the second end 130 of the primary structure 110, the connecting tube 40 is interposed between the second end 130 of the primary structure 110 and the piston rod 21, more precisely the first end 211 of the piston rod 21.

[0099] In a first variant of this first version, the crushing device 30 is interposed between the connecting tube 40 and the piston rod 21 of the linear damper 20.

[0100] When the crushing device 30 comprises a single deformable element 31, the crushing device 30 is reversibly connected on one side to the connecting tube 40 by a fixing interface 35 of the deformable element 31 and on the other side to the piston rod 21 by the other fixing interface 35 of the deformable element 31.

[0101] When the crushing device 30 comprises several deformable elements joined together, the crushing device 30 is connected, reversibly, on the one hand to the connecting tube 40 by a fixing interface 35 of one of the two end deformable elements and on the other hand to the piston rod 21 by a fixing interface 35 of the other end deformable element 31.

[0102] In a second variant of this first version, as illustrated in figure 5, the crushing device 30 replaces a portion of the connecting tube 40.

[0103] When the crushing device 30 comprises a single deformable element 31, the crushing device 30 is connected on both sides to the connecting tube 40 by the two fixing interfaces of the deformable element 31.

[0104] When the crushing device 30 has several deformable elements joined together, the crushing device 30 is connected on both sides to the connecting tube 40 by a fixing interface 35 of each end deformable element 31.

[0105] In this first version, all the embodiments described previously for the deformable element 31 can be used.

[0106] Thus, a 500 vehicle, with landing gear equipped with this first version of the 30 crush device, can advantageously withstand a more brutal vertical landing than a vertical landing under nominal conditions.

[0107] For example, during a vertical landing under normal or extreme conditions, depending on the configuration of the crush device 30, for each landing gear 100, both the crush device 30 and the linear damper 20 are subjected to stress. One or more deformable elements 31 of the crush device 30 will be irreversibly crushed, thereby limiting the force transmitted to the linear damper 20. Each deformable element 31, by crushing along its axis, absorbs the energy associated with the impact. Each deformable element 31 also advantageously possesses the capacity to withstand various stresses, including compressive and bending stresses.

[0108] It is clear that, in this first version, following the impact, if a deformable element 31 is more crushed at the level of one of the landing gears, the vehicle 500 could find itself tilted, or even unstable, as is currently the case for vehicles with landing gear equipped with a honeycomb deformable element 31 integrated into the cylindrical body of a linear damper.

[0109] To overcome this, a second version of the coupling between the crushing device 30 and the linear damper 20.

[0110] In this second version, the crushing device 30 is coupled to the linear damper 20 in a parallel configuration.

[0111] In a first variant of this second version, as illustrated in Figure 6, the linear damper 20 is integrated into a primary connecting rod 140 of the primary structure 110, and the crushing device 30 is integrated into a primary connecting rod 140 of the primary structure 110, which is arranged parallel to the primary connecting rod 140 of the primary structure 110 that includes the linear damper 20. The two primary connecting rods 140 of the primary structure 110 can each be assembled to the structural frame 510 of the vehicle 500. The assembly can be achieved indirectly, through assembly with other primary and secondary connecting rods, or directly.

[0112] The primary connecting rod 140 of the primary structure 110 incorporating the crushing device 30 may include, for example, a connecting tube 40 in which the crushing device 30 is intercalated. To realize this first variant, one can refer to the description of the second variant of the first version.

[0113] In this first variant, all the embodiments described previously for the deformable element 31 can be used.

[0114] In this first variant, for example, during a vertical landing under normal or extreme conditions, depending on the configuration of the crushing device 30, both the crushing device 30 and the linear damper 20 are subjected to stress. One or more deformable elements of the crushing device 30 will be irreversibly crushed, thus limiting the force transmitted to the linear damper 20. Each deformable element 31, by crushing along its axis, absorbs the energy associated with the impact. Each deformable element 31 also advantageously possesses the capacity to withstand various stresses, including compressive and bending stresses. The linear damper 20, for its part, will primarily serve to stabilize the vehicle statically, without the crushing or non-crushing of the crushing device 30 altering the final equilibrium position and thus jeopardizing the stability of the vehicle 500.

[0115] In a second variant of this second version, as illustrated in Figures 7 and 8, the crushing device 30 and the linear damper 20 are both arranged in the same connecting rod 140 of the primary structure 110. The piston rod 21 has, between its two ends 211, 212, a stop element 29 mounted outside the cylindrical body 22. The crushing device 30 is arranged between the cylindrical body 22 and the stop element 29 of the piston rod 21 of the linear damper 20.

[0116] In this second variant, only embodiments with a hollow internal cylindrical space 36, without a lattice structure, for the deformable element 31 can be used. The piston rod 21 is thus positioned in the hollow internal cylindrical space 36. The deformable element 31 then surrounds the piston rod 21.

[0117] Preferably, the fixing interfaces 35 of the deformable element 31 have a through orifice 38 opposite the hollow internal cylindrical space 36. The through orifices 38 of the fixing interfaces 35 advantageously have a dimension adjusted, within a clearance, for the passage and sliding of the piston rod 21. Thus, the deformable element 31, in addition to its function of absorbing shocks, advantageously helps to ensure the stability of the piston rod 21.

[0118] Preferably, according to the needs related to the dimensioning of the linear damper 20 and the crushing device 30, the deformable element 31 comprises one or more inserts 37, as illustrated in view c) of figure 4. This or these inserts 37 comprise(s) a through orifice 39 of size adjusted, within a clearance, for the passage and sliding of the piston rod 21.

[0119] Preferably, to prevent wear of the piston rod 21 from friction with the deformable element 31, the piston rod 21 can be protected by a layer 25, as illustrated in view c) of Figure 4. This layer 25 can be a wear-resistant material or a material with high friction resistance, such as a wear plate. This layer 25 is, for example, fixed to the piston rod 21. This layer 25 can, for example, be made of a Teflon material, or of bronze for direct metal-to-metal contact.

[0120] In one embodiment, as illustrated in Figure 7, the stop element 29 can be positioned on the piston rod 21 such that, when the linear damper 20 is at rest, the length of the crushing device 30 is less than the distance between the stop element 29 and the first end 221 of the cylindrical body 22. In other words, when the linear damper 20 is at rest, a gap exists between the stop element 29 and the crushing device 30. The crushing device 30 can be fixed only to the cylindrical body 22, in a reversible manner.

[0121] In this case, for example, during a vertical landing under nominal or extreme conditions, depending on the configuration of the crushing device 30, the displacement of the piston rod 21 causes the displacement of the stop element 29. The linear damper 20 is preferably dimensioned so that the stop element 29 only comes into contact with the crushing device 30 once a certain level of compression of the linear damper 20 has been reached. When the stop element 29 finally comes into contact with the crushing device 30, one or more deformable elements of the crushing device 30 will then be irreversibly crushed. Each deformable element 31, by crushing along its axis, absorbs the energy associated with the impact. Each deformable element 31 also advantageously has the capacity to withstand various stresses, including compressive stresses, but also bending stresses.Once all the impact energy has been absorbed, the linear damper 20 will continue to function, notably to stabilize the vehicle 500 in a static position. The linear damper 20 can thus maintain the vehicle 500 in an equilibrium position, regardless of whether the deformable element(s) 31 of the crushing device 30 have been irreversibly crushed.

[0122] In another embodiment, as illustrated in Figure 8, the stop element 29 can be positioned on the piston rod 21 such that, when the linear damper 20 is at rest, the length of the crushing device 30 corresponds substantially to the distance between the stop element 29 and the first end 221 of the cylindrical body 22. The crushing device 30 can be fixed on one side to the cylindrical body 22 and on the other side to the stop element 29 of the piston rod 21, in a reversible manner.

[0123] In this second configuration, for example, during a vertical landing under normal or extreme conditions, both the linear damper 20 and the crushing device 30 are subjected to stress. The displacement of the piston rod 21, and therefore the displacement of the stop element 29, immediately causes the irreversible crushing of the deformable element(s) 31 of the crushing device 30. Each deformable element 31, by crushing along its axis, absorbs the energy associated with the impact. Each deformable element 31 also advantageously possesses the capacity to withstand various stresses, including compressive and bending stresses. Once all the impact energy has been absorbed, the linear damper 20 will continue to function, notably to stabilize the vehicle 500 in a static position.The linear damper 20 can thus maintain the vehicle 500 in an equilibrium position, regardless of whether the deformable element(s) of the crushing device 30 have been irreversibly crushed. Since the crushing device 30 intervenes from the outset, the stresses exerted on the linear damper 20 are thus significantly reduced. The foregoing description clearly illustrates that, through its various features and their advantages, the present invention achieves its intended objectives. In particular, the present invention makes it possible to obtain a landing gear for a vertical landing vehicle with improved absorption capacity during the landing phase, while limiting its mass.Furthermore, regardless of the configuration of the crushing device relative to the linear damper, the crushing device is positioned outside the cylindrical body of the linear damper 20, making it more accessible to an operator. Thanks to its reversible mounting, the crushing device is replaceable. It can be changed independently of the linear damper, simplifying replacement operations for an operator.

Claims

Demands Claim 1. Landing gear (100) of a vertical landing vehicle (500), said landing gear comprising a damping assembly including: - a linear damper (20) comprising a piston rod (21) mounted to slide within a cylindrical body (22), - a crushing device (30) comprising at least one element configured to absorb energy by crushing, called a deformable element (31), the crushing device (30) being arranged outside the cylindrical body (22), and coupled to the linear damper (20) in a parallel configuration, each deformable element (31) being obtained by additive manufacturing and comprising a lattice structure (32), characterized in that each deformable element (31) is configured to deform irreversibly, in that the landing gear (100) comprises a primary structure (110) comprising one or more primary connecting rods (140), and in that: - the crushing device (30) is integrated into a primary connecting rod (140) connected in parallel with another primary connecting rod (40) incorporating the linear damper (20), the crushing device (30) being assembled reversibly, or - the crushing device (30) and the linear damper (20) are integrated into the same primary connecting rod (140), the piston rod (21) having a stop element (29) mounted outside the cylindrical body (22), the crushing device (30) being arranged between the cylindrical body (22) and the stop element (29) of the piston rod (22), the crushing device being assembled reversibly. Claim 2. Landing gear (100) according to claim 1 in which the crushing device (30) comprises a plurality of deformable elements (31) joined together, the deformable elements (31) being identical or not. Claim s. Landing gear (100) according to any one of the preceding claims in which the lattice structure (32) of a deformable element (31) has an overall cylindrical shape, preferably of circular cross-section. Claim 4. Landing gear (100) according to any one of the preceding claims in which a deformable element (31) comprises an outer wall (33) surrounding the lattice structure (32). Claim s. Landing gear (100) according to any one of the preceding claims in which a deformable element (31) comprises, along the entire length of the lattice structure (32), a hollow internal cylindrical space (36) without a lattice structure. Claim 6. Landing gear (100) according to the preceding claim, wherein a deformable element (31) comprises, along the entire length of the lattice structure (32), an internal wall (34) delimiting the internal hollow cylindrical space (36). Claim 7. Vertical landing vehicle (500) comprising a structural frame (510) and at least one landing gear (100) according to any one of claims 1 to 6, each landing gear being connected to the structural frame by a fastening member (520).

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