Landing gear and design method thereof, aircraft

Abstract

The present invention discloses a landing gear, a design method thereof, and an aircraft, relating to the technical field of landing gear. The landing gear comprises at least two skids, at least two buffer beams, and at least two mounting brackets. The two skids are arranged opposite each other. The buffer beam connects the two skids and protrudes upward. The buffer beam comprises a transverse beam section and two curved beam sections, with the curved beam sections connected between the transverse beam section and the skids. The mounting brackets are used to connect to the aircraft body. The two mounting brackets are disposed at opposite ends of a transverse beam section, with a spacing d between the two mounting brackets. The width of the landing gear in the distribution direction of the mounting brackets is D, and 0.3≤d / D≤0.7 is achieved. The technical solution provided by the present invention can enhance the cushioning and energy absorption effect of the landing gear.

Description

Technical Field

[0001] The present invention relates to the technical field of landing gears, and in particular to a landing gear and a design method thereof, and an aircraft. Background Art

[0002] As an aircraft's energy-absorbing structure, the landing gear's structural stability and mechanical properties play a crucial role. Skid-type landing gear typically consists of two skids and two arched beams located at the front and rear ends of the skids. The arched beams are typically arranged to project upward, with their midsections connected to the aircraft body via mounting brackets, and their ends connected to the skids. However, the arched beams typically only serve to transfer loads and are ineffective at absorbing energy. Therefore, improving the energy-absorbing performance of the arched beams and mounting brackets is a pressing issue in the field. Summary of the Invention

[0003] The main purpose of the present invention is to provide a landing gear and a design method thereof, and an aircraft, in order to improve the buffering and energy absorption effect of the landing gear.

[0004] To achieve the above-mentioned object, the landing gear proposed by the present invention includes:

[0005] There are at least two slides, and the two slides are arranged opposite to each other;

[0006] At least two buffer beams are provided, the buffer beams connecting the two slides and protruding upward, the buffer beams having a transverse beam section capable of elastic deformation and two curved beam sections, the curved beam sections being connected between the transverse beam section and the slides; and

[0007] At least two mounting brackets are used to connect the aircraft body, the two mounting brackets are respectively arranged at opposite ends of a horizontal beam section, and the spacing between the two mounting brackets is d, the width of the landing gear in the distribution direction of the mounting brackets is D, 0.3≤d / D≤0.7.

[0008] In one embodiment, 0.45≤d / D≤0.5.

[0009] In one embodiment, at least two of the buffer beams include a front beam and a rear beam, and the transverse and vertical beam sections of the front beam and the rear beam are each provided with at least two mounting brackets. The rear beam is close to the center of gravity of the aircraft, and the d / D value on the rear beam is smaller than the d / D value on the front beam.

[0010] In one embodiment, at least two of the buffer beams include a front beam, and a curved beam section of the front beam is bent and extended outwardly toward the rear and butted against the front end of the slide.

[0011] In one embodiment, a front curved section extends from the front end of the slide toward the upper front side, and the front curved section protrudes outward and is connected to the curved beam section of the front beam.

[0012] In one embodiment, a rear warping section is extended from the rear end of the skid toward the rear and upward side, and the radii of the rear warping section, the front warping section, and the curved beam section are configured to be the same.

[0013] In one embodiment, the rear warping section, the front warping section and the curved beam section are formed and arranged by a bending machine, and the bending radius is configured to be the same.

[0014] In one embodiment, the landing gear further includes a first joint, the front beam and the skid are respectively inserted at opposite ends of the first joint, and the front beam and / or the skid are fixedly connected to the first joint via a connecting member.

[0015] In one embodiment, a ratio of a depth of the front beam inserted into the first joint to a diameter of the front beam ranges from 1 to 2.

[0016] In one embodiment, a ratio of a depth of the slider inserted into the first joint to a diameter of the slider ranges from 1 to 2.

[0017] In one embodiment, the buffer beam is made of spring steel, and the slide is made of deformed aluminum alloy.

[0018] In one embodiment, the buffer beam and / or the skid is a tubular structure, and the cross-section is circular, elliptical or polygonal.

[0019] In one embodiment, the landing gear further includes an anti-wear plate, and the anti-wear plate is provided on the lower side of the skid.

[0020] In one embodiment, at least two of the buffer beams include a rear beam, and the landing gear further includes a second joint, the second joint is provided with a socket and a buckle groove, the end of the rear beam is inserted into the socket and fixed by a bolt, and the buckle groove is buckled on the upper side of the skid and fixed by a rivet.

[0021] In one embodiment, the mounting bracket includes a mounting seat and a retaining structure, the mounting seat is connected to the aircraft body, and the retaining structure connects the mounting seat and the buffer beam to limit the mounting seat from separating from the buffer beam in the up and down directions.

[0022] In one embodiment, the side wall of the mounting seat is provided with a downward-facing yielding groove, and the anti-slip structure includes an anti-slip boss, an installation boss and a locking member. The anti-slip boss extends outward from the edge of the slot of the yielding groove, and the installation boss is installed on the buffer beam. The yielding groove can be sleeved on the installation boss from top to bottom, and the locking member is detachably installed on the installation boss and abuts against the upper side of the anti-slip boss.

[0023] In one embodiment, the mounting boss is a stud, and the locking member includes a nut and an anti-slip washer. The nut is locked on the mounting boss, and the anti-slip washer is clamped on the mounting seat, and the anti-slip washer abuts against the upper side of the anti-slip boss.

[0024] In one embodiment, the nut is a slotted nut, and the slotted nut is fixed relative to the stud in the circumferential direction by a cotter pin.

[0025] In one embodiment, the connection gap between the nut and the stud is filled with protective glue.

[0026] In one embodiment, the mounting bracket also includes a clamp, which includes a first clamp body and a second clamp body connected to each other, the first clamp body and the second clamp body jointly clamp the buffer beam and enable the clamp to rotate around an axis extending in the left and right directions; the first clamp body is arranged above the second clamp body and is used to connect to the aircraft body.

[0027] In one embodiment, the mechanical strength of the first hoop body is greater than that of the second hoop body.

[0028] In one embodiment, the first hoop body and the second hoop body are provided with reinforcing ribs, and the reinforcing ribs surround the outer peripheral surface of the clamp along the front-rear direction of the landing gear. The number of reinforcing ribs on the first hoop body is greater than the number of reinforcing ribs on the second hoop body, and the multiple reinforcing ribs on the first hoop body are arranged along the left-right direction of the landing gear.

[0029] In one embodiment, the landing gear further includes a limiting bracket, which is provided on the buffer beam and cooperates with the mounting bracket to limit the lateral displacement of the mounting bracket.

[0030] In one embodiment, two limiting brackets are provided and are located at the interval between two mounting brackets on the same buffer beam, and the limiting bracket abuts against the end surface of the mounting bracket close to the other mounting bracket.

[0031] In one embodiment, the limiting bracket is configured as a clamp and is arranged on the peripheral side surface of the buffer beam.

[0032] In one embodiment, the mounting bracket has a mounting channel, the buffer beam is inserted into the mounting channel, and the landing gear further includes an elastically deformable shock-absorbing pad, which is arranged between the side wall of the mounting channel and the peripheral side of the buffer beam.

[0033] In one embodiment, a stop flange extends inwardly from the end surface of the installation channel, and the inner end surface of the stop flange abuts against the end surface of the shock-absorbing pad.

[0034] In one embodiment, the mounting bracket has a mounting channel, the buffer beam is passed through the mounting channel, a stop flange extends inwardly from the end surface of the mounting channel, and the outer end surface of the stop flange abuts against the limiting bracket.

[0035] The present invention also provides a landing gear design method, comprising the steps of:

[0036] Constructing an initial wireframe model of the landing gear; wherein the initial wireframe model includes two skids of the landing gear and a buffer beam connected between the two skids, the buffer beam including a transverse beam section and a curved beam section, the curved beam section connected between the transverse beam section and the skids, two fuselage mounting points being provided at opposite ends of the transverse beam section, and the distance between the two fuselage mounting points being d;

[0037] Constructing a primary simulation model of the landing gear based on the initial wireframe model, and performing mechanical analysis and modal analysis;

[0038] If the results of the mechanical analysis and modal analysis of the primary simulation model meet the requirements, the primary simulation model is judged to be qualified;

[0039] If not, the primary simulation model is optimized and iterated until the analysis results meet the requirements;

[0040] The value of the distance d is determined based on a qualified primary simulation model.

[0041] In one embodiment, the landing gear design method further comprises the steps of:

[0042] The landing gear design method further comprises the steps of:

[0043] According to the primary simulation model and the connection structure between the skid and the buffer beam, a secondary simulation model of the landing gear is constructed; wherein the bending radius of the curved beam section of the secondary simulation model is R G ;

[0044] Perform drop simulation analysis on the secondary simulation model to determine the minimum bending radius R of the curved beam segment. Gm ; Wherein, the bending radius R G Greater than the minimum bending radius RGm .

[0045] In one embodiment, the skid of the secondary simulation model is provided with a rear warping section at the rear end, and the bending radius of the rear warping section is R R ;

[0046] The step of performing drop shock simulation analysis on the secondary simulation model is also used to determine the minimum unyielding radius R of the rear warping section of the landing gear when the landing gear is flipped over and landed. Rm ; Wherein, the bending radius R R Greater than the minimum unyielding radius R Rm .

[0047] In one embodiment, the slide of the secondary simulation model is provided with a front warping section at the front end, and the bending radius of the front warping section is R F ;

[0048] The step of performing drop simulation analysis on the secondary simulation model is also used to determine the minimum bending radius R of the front warping section. Fm ; Wherein, the bending radius R F Greater than the minimum bending radius R Fm .

[0049] In one embodiment, the bending radius R G , bending radius R R and bending radius R F The value of is the same and is greater than the minimum bending radius R Gm , minimum unyielding radius R Rm and minimum bending radius R Fm The largest one among them.

[0050] In one embodiment, the step of performing a drop simulation analysis on the secondary simulation model is further used to obtain stress results of the landing gear and absorption results of the multi-stage energy absorbing structure, and determine whether the secondary simulation model is qualified based on the stress results and absorption results;

[0051] Among them, the multi-level energy absorption structure includes a first-level absorption structure formed by the bending deformation of the horizontal beam section, a second-level absorption structure formed by the bending deformation of the curved beam section, and a third-level absorption structure formed by the bending deformation of the front warping section. The energy absorption amount of the first-level absorption structure is E1, the energy absorption amount of the second-level absorption structure is E2, and the energy absorption amount of the third-level absorption structure is E3.

[0052] The present invention further provides an aircraft, comprising an aircraft body and the aforementioned landing gear, wherein the landing gear is arranged on the lower side of the aircraft body.

[0053] In the technical solution of the present invention, firstly, the buffer beam not only transmits loads but also absorbs impact loads through the elastic deformation of the transverse and curved beam sections, thereby effectively absorbing energy and improving the landing gear's energy absorption. Secondly, by maximizing the distance between the two mounting brackets on the same buffer beam, the length of the deformable portion of the buffer beam (i.e., the transverse and vertical beam sections) can be increased, which helps improve the landing gear's energy absorption. Secondly, it can also reduce the vibration amplitude of the aircraft body, thereby making the aircraft body more stable and helping to avoid resonance between the landing gear and the fuselage. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0055] Figure 1 A schematic structural diagram of an embodiment of a landing gear provided by the present invention;

[0056] Figure 2 for Figure 1 Exploded view of the structure shown at the mounting bracket;

[0057] Figure 3 for Figure 2 The schematic diagram of the assembly relationship of the structure shown is after the mounting base is hidden;

[0058] Figure 4 for Figure 1 a top view of the structure shown;

[0059] Figure 5 for Figure 1 a side view of the structure shown;

[0060] Figure 6 for Figure 1 a front view of the structure shown;

[0061] Figure 7 for Figure 1 A partial enlarged view of the structure shown at the second joint;

[0062] Figure 8 for Figure 7 A schematic structural diagram of the second joint in FIG;

[0063] Figure 9 for Figure 1 Another side view of the structure shown.

[0064] Description of Figure Numbers:

[0065] 10. Sled; 11. Front warping section; 12. Rear warping section;

[0066] 20. Buffer beam; 201. Horizontal and vertical beam sections; 202. Curved beam sections; 21. Front beam; 22. Rear beam;

[0067] 30. Mounting bracket; 301. Mounting channel; 31. Hoop; 311. First hoop body; 312. Second hoop body; 313. Stop flange; 314. Reinforcement rib; 32. Mounting seat; 321. Through slot; 33. Anti-slip structure; 331. Anti-slip boss; 332. Mounting boss; 333. Locking member; 334. Anti-slip gasket;

[0068] 40. Limiting bracket; 41. Third hoop;

[0069] 51, first connector; 52, second connector; 521, jack; 522, buckle slot;

[0070] 61. Rivet; 62. Nut; 63. Split pin;

[0071] 70. Shock-absorbing pad; 80. Anti-wear pad.

[0072] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0073] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0074] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0075] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0076] The landing gear serves as the buffer and energy-absorbing structure of the aircraft, and its structural stability and mechanical properties play a key role. A skid-type landing gear usually includes two skids and two buffer beams distributed at the front and rear ends of the skids. The middle part of the buffer beam is connected to the aircraft body through a mounting bracket, and the end of the buffer beam is connected to the skid. However, during the take-off or landing phase of the aircraft, the load on the landing gear changes significantly. Therefore, the mounting bracket located on the buffer beam is prone to lateral slippage during these processes, which may cause uneven force on the left and right side structures of the landing gear and cause the structure on one side to fail first. Therefore, how to improve the installation stability of the mounting bracket and reduce the probability of lateral slippage is a problem that urgently needs to be solved in this field.

[0077] In view of this, the present invention provides a landing gear, which can improve the installation stability of the mounting bracket and reduce the probability of lateral slippage.

[0078] See also Figure 1 In one embodiment of the present invention, the landing gear includes at least two skids 10 and at least two bumper beams 20. The at least two skids 10 are positioned opposite each other, and the bumper beams 20 connect the two skids 10. The at least two bumper beams 20 project upward and are spaced apart along the extension direction of the skids 10, and are used for mounting to the aircraft body. Specifically, the upwardly projecting bumper beams 20 may be generally arched in shape. This allows the elastic deformation of the arched structure to absorb impact energy experienced by the landing gear.

[0079] Without loss of generality, the aircraft body includes a fuselage and a propeller arranged on the fuselage. The fuselage is installed above the buffer beam and has a crew cabin for the pilot and passengers.

[0080] See also Figure 1 and Figure 4Optionally, the buffer beam 20 includes an elastically deformable transverse beam section 201 and two curved beam sections 202, with the curved beam sections 202 connected between the transverse beam section 201 and the skid 10. Thus, in this embodiment, the buffer beam 20, in addition to transmitting loads, can also absorb impact loads through the elastic deformation of the transverse beam section 201 and the curved beam section 202, thereby effectively absorbing energy and improving the landing gear's energy absorption performance.

[0081] See also Figure 1 and Figure 2 Furthermore, the landing gear also includes at least two mounting brackets 30 disposed on the bumper beam 20. The mounting brackets 30 are used to connect to the aircraft body. Thus, the mounting brackets 30 facilitate the installation of the landing gear and the aircraft body. Of course, in other embodiments, the mounting brackets 30 may not be provided.

[0082] Optionally, the at least two buffer beams 20 include a front beam 21 and a rear beam 22. Each of the transverse and vertical beam sections 201 of the front beam 21 and the rear beam 22 is provided with at least two mounting brackets 30. In this embodiment, two mounting brackets 30 are optionally provided on each of the front beam 21 and the rear beam 22, meaning the landing gear is provided with a total of four mounting brackets 30. This ensures the stability of the aircraft's mounting and increases the load transfer path between the landing gear and the aircraft, thereby enhancing the landing gear's energy absorption and buffering capabilities.

[0083] It should be noted that during the landing gear design process, deformation coordination analysis is performed on the landing gear structure that meets static strength requirements. Specifically, within the aircraft's forward and rearward limits of the center of gravity, the front and rear beams 21 and 22 are subjected to static strength simulations of gravity and overload. This ensures that the deformation of the front and rear beams 21 and 22 is coordinated and consistent, ensuring that the front and rear deformations of the landing gear are consistent, and that the rollover moment (e.g., rollover moment or backflip moment) is less than the restoring moment, thereby preventing the aircraft from tipping over. Specifically, the vertical deformation of the front and rear beams 21 and 22 is required to be as consistent as possible, ensuring that the vertical (i.e., vertical) displacements of the four mounting brackets 30 (i.e., fuselage mounting points) on them are consistent. This allows the aircraft to land in a relatively stable posture and prevent tipping over.

[0084] The vertical deformation of the bumper beam 20 is primarily determined by the deformation of the curved beam section 202, which also plays a major role in buffering and absorbing energy. Therefore, the length of the curved beam section 202 (i.e., its width in the left-right direction of the landing gear) is typically designed to be large. In this embodiment, since the bumper beam 20 as a whole is elastically deformable, the transverse beam section 201 can also elastically deform and absorb energy. However, if the length of the curved beam section 202 is set too large, the transverse beam section 201 will be too small, which is not conducive to the transverse beam section 201 fully utilizing its deformation and energy absorption function.

[0085] Therefore, while the existing technology usually designs the length of the curved beam section 202 to be very large, the present invention specifically increases the length of the horizontal beam section 201 and increases the distance between the two mounting brackets 30 so that the horizontal beam section 201 can fully play its deformation and energy absorption role. Figure 4 Optionally, two mounting brackets 30 are disposed at opposite ends of a transverse beam section 201, with a spacing d between the two mounting brackets 30. The width of the landing gear in the distribution direction of the mounting brackets 30 is D, and 0.3 ≤ d / D ≤ 0.7. It will be appreciated that the value of the spacing d is positively correlated with the length of the transverse beam section. That is, the longer the transverse beam section, the larger the spacing d, and vice versa.

[0086] In this embodiment, the transverse beam section 201 located between the two mounting brackets 30 is elastically deformable to absorb energy. By maximizing the distance between the two mounting brackets 30 on the same bumper beam 20, the length of the deformable central portion of the bumper beam 20 (i.e., the transverse beam section 201) is increased, thereby improving the landing gear's energy absorption and cushioning capabilities. Furthermore, this reduces the vibration amplitude of the aircraft, further stabilizing its posture and preventing resonance between the landing gear and the fuselage.

[0087] Of course, the distance d between the two mounting brackets 20 should not be excessively increased, as the curved beam section 202 must also be able to adequately perform its energy-absorbing function. Therefore, preferably, 0.45 ≤ d / D ≤ 0.5, for example, d / D is 0.45, 0.47, or 0.5. This ensures that the curved beam section 202 has sufficient length to fully perform its deformation-absorbing function and also ensures that the vertical deformation of the impact beam 20 is sufficiently large during landing, thereby lowering the center of gravity and improving landing safety.

[0088] Optionally, the bumper beam 20 is made of a metal material with excellent elastic properties, such as spring steel, while the skid 10 is made of a metal material with low density, high specific strength, and high specific stiffness, such as a deformed aluminum alloy. Specifically, the bumper beam 20 and skid 10 are manufactured from spring steel and a deformed aluminum alloy, respectively, and the two are physically coupled to form the landing gear. The spring steel bumper beam 20 has sufficient strength and toughness to withstand impact loads, while the deformed aluminum alloy skid 10 has sufficient strength and low modulus, significantly increasing the material deformation energy absorption efficiency of the landing gear.

[0089] This, on the one hand, can minimize the overall weight of the landing gear while still meeting strength requirements; on the other hand, can fully utilize the overall deformation energy absorption function of the landing gear, allowing the landing gear to effectively absorb impact loads and improve the safety of the aircraft. Of course, in other embodiments, the material of the buffer beam 20 and the skid 10 can also be set to aluminum alloy, spring steel, or other materials.

[0090] Optionally, the bumper beam 20 and the skid 10 are tubular structures with circular, elliptical, or polygonal cross-sections. For example, both the bumper beam 20 and the skid 10 are circular tubes. This provides a stable structure with excellent mechanical properties, which contributes to the structural stability and energy absorption of the landing gear. Of course, in other embodiments, only the bumper beam 20 or the skid 10 may be configured as a circular tube, or both the bumper beam 20 and the skid 10 may be configured as elliptical or square tubes. In other embodiments, the bumper beam 20 and the skid 10 may be configured as solid rod-shaped structures.

[0091] In order to avoid the problem of easy wear of the skid 10, the deformed aluminum alloy in this embodiment can optionally be an ultra-hard deformed aluminum alloy. Of course, other means can also be used to solve this problem at the same time. For example, in one embodiment, the landing gear further includes an anti-wear plate 80, which is provided on the lower side of the skid 10. Optionally, the anti-wear plate 80 can be made of a high-hardness metal, such as stainless steel, titanium alloy, or tungsten steel, and can be fixed to the skid 10 by rivets 61. In this way, the anti-wear plate 80 can prevent the lower side of the skid 10 from directly contacting the ground, thereby preventing the skid 10 from being easily worn due to direct contact with the ground and increasing the service life of the skid 10. Of course, in other embodiments, the anti-wear plate 80 can also be omitted.

[0092] Optionally, multiple wear plates 80 can be installed on the same skid 10, with one wear plate 80 located at the front contact point of the skid 10, another at the rear contact point of the skid 10, and a third located in the middle of the skid 10. The front and rear contact points are well known in the art of landing gear and will not be described in detail here. This allows the skid 10's contact surface to remain suspended relative to the ground thanks to the multiple wear plates 80, further reducing the risk of wear on the skid 10.

[0093] See also Figures 4 to 6 In one embodiment, at least two buffer beams 20 include a front beam 21. The ends of the front beam 21 include a curved beam section 202. The curved beam section 202 curves outward and extends laterally and rearward, abutting the front end of the skid 10. Specifically, the center of the curved beam section 202 is located to the side of the center of the landing gear, and the distance between the two curved beam sections 202 gradually increases from front to rear. This allows the curved beam sections 202 to bend and deform to absorb impact loads, thereby enhancing the landing gear's energy absorption. Furthermore, the curved beam sections 202 curve outward and extend laterally and rearward, increasing the distance between the two skids 10, thereby increasing the overall width of the landing gear and ensuring a sufficient rollover angle for the aircraft. It also reduces air resistance and improves the aerodynamics of the landing gear, thereby reducing wind resistance during flight. Of course, in other embodiments, the front beam 21 can have other structural configurations. For example, the ends of the front beam 21 may curve downward, but not extend laterally and rearward.

[0094] See also Figures 4 to 6 Optionally, a front curved section 11 extends upward and forward from the front end of the sled 10. The front curved section 11 protrudes outward and connects to the curved beam section 202. Thus, the front curved section 11 and the curved beam section 202 form a smoothly transitioned arc-shaped structure. This not only continuously transfers the impact energy borne by the buffer beam 20 to the sled 10, allowing the sled 10 to also absorb energy, but also allows the front curved section 11 to elastically deform and absorb impact energy.

[0095] See also Figure 9 In this embodiment, the rear beam is positioned close to the center of gravity of the aircraft, and the d / D ratio on the rear beam is smaller than that on the front beam. For example, if the d / D ratio on the rear beam is 0.45, the d / D ratio on the front beam can be 0.46, 0.47, 0.48, 0.49, or 0.5, etc.

[0096] Specifically, in this embodiment, the center of gravity of the aircraft is closer to the rear beam 22 in the fore-aft direction of the landing gear. Therefore, when the aircraft lands, the rear beam 22 needs to bear and transmit a greater load. Therefore, on the one hand, by increasing the length of the curved beam section 202 of the rear beam 22, the rear beam 22 can bear and absorb more impact energy.

[0097] On the other hand, because the curved beam section 202 of the front beam 21 abuts the front warped section 11 of the skid 10, the vertical displacement of the mounting bracket 30 on the front beam 21 is affected by both the curved beam section 202 and the front warped section 11. That is, under the same load, the simultaneous deformation of the curved beam section 202 and the front warped section 11 of the front beam 21 increases the vertical displacement of the mounting bracket 30 on the front beam 21. To ensure consistent vertical displacement of the four mounting brackets 30 on the front and rear beams 21, the vertical displacement of the mounting bracket 30 on the rear beam 22 is increased by making the curved beam section 202 of the rear beam 22 longer (i.e., setting a smaller d / D ratio on the rear beam 22). In other words, in this embodiment, considering the structural characteristics of the curved beam section 202 of the front beam 21 abutting the end of the skid 10, the d / D ratio on the rear beam 22 is set to be smaller than that on the front beam 21.

[0098] Optionally, a rear warped section 12 extends upward and rearward from the rear end of the slider 10. The radius of the rear warped section 12, the front warped section 11, and the curved beam section 202 are configured to be the same. By unifying the curvature radius of the bumper beam 20 and the slider 10, the parameter design of the elements required for consideration in the design method can be simplified, thereby improving design efficiency and reducing design costs.

[0099] To reduce the production cost of the landing gear, in one embodiment, the curved beam section 202 and the front warping section 11 are optionally formed using a press brake, and the bending radius of the curved beam section 202 and the front warping section 11 are configured to be the same. That is, the buffer beam 20 and the skid 10 are respectively formed into the curved beam section 202 and the front warping section 11 using a press brake and a tube bending mold. In this way, the curved beam section 202 and the front warping section 11 can share the same tube bending mold, thereby reducing the number of tube bending molds required for production and lowering the production cost of the landing gear. Of course, in other embodiments, the bending radius of the curved beam section 202 and the front warping section 11 can be set to different, or the bending process can be omitted.

[0100] Optionally, a rear warped section 12 extends upward and rearward from the rear end of the skid 10. The bending radius of the rear warped section 12 is configured to be the same as that of the front warped section 11. The bending radius of the front beam 21 and the rear beam are also configured to be the same. That is, in this embodiment, the rear warped section 12, the front warped section, and the curved beam section are formed using a bending machine, all with the same bending radius. All locations within the landing gear structure requiring bending are formed using the same bending mold, thus further reducing the number of bending molds required.

[0101] It is worth mentioning that in the embodiment of the present invention, the main structure of the landing gear is formed by adopting a buffer beam 20 made of spring steel and a skid 10 made of deformed aluminum alloy, and the longitudinal rotation freedom of the mounting bracket 30 on the buffer beam 20 is released. At the same time, a curved beam section 202 and a front warping section 11 are provided, so that the overall elastic deformation of the landing gear is fully changed, thereby achieving a multi-stage energy absorption effect of the landing gear.

[0102] Specifically, after the landing gear is subjected to an impact load, part of the energy can be absorbed by the middle part of the buffer beam 20 by releasing its bending freedom and undergoing elastic deformation, another part of the energy can be absorbed by the bending deformation of the curved beam section 202 of the buffer beam 20, another part of the energy can be absorbed by the bending deformation of the front warped section 11 of the skid 10, and another part of the energy can be absorbed by the friction between the anti-wear plate 80 and the ground.

[0103] It is understood that there are many ways to achieve physical coupling between the buffer beam 20 and the skid 10, for example, see Figure 1 In one embodiment, the landing gear further includes a first joint 51. The front beam 21 and the skid 10 are respectively inserted at opposite ends of the first joint 51. The front beam 21 and / or skid 10 are fixedly connected to the first joint 51 via a connector. Optionally, the connector is a rivet 61. The first joint 51 is a tubular structure that can be sleeved over the front beam 21 and skid 10. This provides a simple and easy-to-implement structure. Of course, in other embodiments, the front beam 21 can be directly welded to the skid 10, or the connector can be screwed.

[0104] In order to improve the installation reliability of the front beam 21, the slide 10 and the first joint 51, optionally, the ratio of the depth of the front beam 21 inserted into the first joint 51 to the diameter of the front beam 21 is in the range of 1 to 2, for example, a value of 1.3, 1.5 or 1.7; the ratio of the depth of the slide 10 inserted into the first joint 51 to the diameter of the slide 10 is in the range of 1 to 2, for example, a value of 1.3, 1.5 or 1.7.

[0105] See also Figure 5 、 Figure 7 and Figure 8Furthermore, at least two buffer beams 20 include a rear beam 22, and the landing gear also includes a second joint 52. The second joint 52 has a socket 521 and a latching slot 522. The end of the rear beam 22 is inserted into the socket 521 and secured by bolts. The latching slot 522 latches onto the upper side of the skid 10 and is secured by rivets 61. Optionally, the second joint 52 has a roughly T-shaped structure, that is, the extension direction of the socket 521 and the extension direction of the latching slot 522 intersect. This provides a simple structure and is easy to implement. Of course, in other embodiments, the rear beam 22 can also be directly welded to the skid 10.

[0106] It's worth noting that the landing gear of the present invention utilizes different types of rivets 61 depending on the forces they bear. High-strength rivets are used in connection locations subject to high forces, while standard-strength rivets, such as ordinary stainless steel rivets, are used in connection locations subject to low forces. Specifically, high-strength rivets are used in the first and second joints 51 and 52, while standard-strength rivets are used in the wear plate 80. This reduces the production cost of the landing gear while ensuring sufficient rivet connection strength. Of course, in other embodiments, all rivets on the landing gear can be of the same type and specification.

[0107] It is understood that the mounting bracket 30 has various structural forms, for example, see Figure 2 and Figure 3 In one embodiment, the mounting bracket 30 includes a clamp 31, which comprises a first clamp body 311 and a second clamp body 312. The first clamp body 311 and the second clamp body 312 jointly clamp the bumper beam 20 and enable the clamp 31 to rotate about an axis extending in the left-right direction. This releases the clamp 31's longitudinal rotational freedom, that is, allows the clamp 31 to rotate about the transverse axis. When the landing gear is subjected to an impact load, the bumper beam 20 can undergo sufficient bending deformation to absorb energy, thereby enhancing the landing gear's energy absorption performance. In other words, the clamp 31's ability to rotate about the left-right axis releases the directional rotational constraint caused by deformation of the bumper beam 20. This allows the bumper beam 20's transverse beam section 201 and curved beam section 202 to deform together, thereby increasing the landing gear's cushioning capacity. Of course, in other embodiments, the mounting bracket 30 may also be of other structural forms. For example, the mounting bracket 30 includes a curved plate and a straight plate. The curved plate covers the upper side of the buffer beam 20 and is fixed by bolts or rivets 61. The straight plate is arranged on the upper side of the curved plate and is fixed to the aircraft body by bolts or rivets 61.

[0108] See also Figure 2Furthermore, the mounting bracket 30 includes a mounting seat 32 and a retaining structure 33. The mounting seat 32 is connected to the aircraft body, and the retaining structure 33 connects the mounting seat 32 and the bumper beam 20 to prevent the mounting seat 32 from vertically separating from the bumper beam 20. Thus, the retaining structure 33 implements an anti-drop design, effectively preventing the mounting seat 32 from vertically separating from the bumper beam 20 during flight or when the landing gear is subjected to downward loads, thereby preventing the landing gear from separating from the aircraft body. Of course, in other embodiments, the retaining structure 33 may not be provided, and the mounting seat 32 may be directly welded to the bumper beam 20.

[0109] Optionally, the side wall of the mounting seat 32 is provided with a downward-facing yielding groove 321, and the anti-slip structure 33 includes an anti-slipping boss 331, a mounting boss 332 and a locking member 333. The anti-slipping boss 331 extends outward from the edge of the slot of the yielding groove 321, and the mounting boss 332 is installed on the buffer beam 20. The yielding groove 321 can be sleeved on the mounting boss 332 from top to bottom, and the locking member 333 is detachably installed on the mounting boss 332 and abuts against the upper side of the anti-slipping boss 331.

[0110] Optionally, the first hoop body 311 is disposed above the second hoop body 312 and is used to connect to the aircraft body, and the mounting boss 332 is fixedly disposed on the first hoop body 311 .

[0111] Specifically, see Figure 2 and Figure 3 When the locking cam 331 is unlocked, the locking cam 332 is unlocked and the locking cam 333 is unlocked, so that the cam 332 can be unlocked when the locking cam 332 is unlocked.

[0112] See also Figure 2 Alternatively, the mounting boss 332 is a stud, and the locking member 333 includes a nut 62 and a locking washer 334. The nut 62 is locked onto the mounting boss 332 and clamps the locking washer 334 onto the mounting seat 32. The locking washer 334 abuts against the upper side of the locking boss 331. This simplifies the structure and facilitates installation, removal, and maintenance of the mounting seat 32 and the first hoop body 311.

[0113] It should be noted that the landing load of the landing gear is transmitted through extrusion, that is, the landing gear's own gravity and the downward inertial load on the landing gear due to flight will be transmitted to the aircraft body through the anti-slip gasket 334 on the mounting boss 332.

[0114] Of course, in other embodiments, the mounting boss 332 may not be provided with an external thread, and the locking member 333 may be a sheet-like structure and can be sleeved on the mounting boss 332. When the locking member 333 abuts against the anti-slip boss 331, it is welded and fixed to the mounting boss 332.

[0115] Optionally, the nut 62 in the locking member 333 is a slotted nut, which is circumferentially fixed relative to the stud by a cotter pin 63. In this way, the problem of the nut 62 loosening or even coming off can be avoided, thereby improving the installation reliability of the mounting base 32.

[0116] Optionally, the gap between the nut 62 and the stud is filled with a protective adhesive (not shown in the accompanying drawings). The protective adhesive can be a waterproof adhesive, such as an epoxy waterproof sealant, anaerobic adhesive, or a pre-applied thread locker. This protective adhesive not only prevents the nut 62 from loosening, but also effectively prevents corrosion and failure of the threads on the nut 62 and stud. Of course, in other embodiments, the protective adhesive may not be provided.

[0117] Optionally, the stop flange 313 is provided on the first hoop body 311 and / or the second hoop body 312, for example, see Figure 2 , the stop flange 313 may be provided only on the second hoop body 312 .

[0118] Optionally, the mechanical strength of the first hoop body 311 is greater than that of the second hoop body 312. It should be noted that the mechanical strength of the first hoop body 311 is greater than that of the second hoop body 312, which means that the structural strength of the first hoop body 311 is greater than that of the second hoop body 312. This strength difference can be achieved by using materials of different strengths or by using different structural parameters (such as material thickness).

[0119] See also Figure 4 Optionally, the first hoop body 311 and the second hoop body 312 are provided with reinforcing ribs 314, and the reinforcing ribs 314 surround the outer peripheral surface of the clamp 31 along the front and rear direction of the landing gear. The number of reinforcing ribs 314 on the first hoop body 311 is greater than the number of reinforcing ribs 314 on the second hoop body 312, and the multiple reinforcing ribs 314 on the first hoop body 311 are arranged along the left and right direction of the landing gear.

[0120] Specifically, in this embodiment, the first hoop 311 is provided with three reinforcing ribs 314, and the second hoop 312 is provided with one reinforcing rib 314. It will be appreciated that, because the first hoop 311 is primarily subjected to the impact load of the aircraft landing and must withstand significant shear forces, requiring high strength, it is therefore manufactured from ultra-high-strength steel and has multiple reinforcing ribs 314. The second hoop 312, on the other hand, is only subjected to the gravity of the landing gear after takeoff and is subject to less force, and is therefore manufactured from ordinary structural steel and has only one reinforcing rib 314. This allows this embodiment to minimize weight and cost while still meeting the requirements for landing gear strength and impact resistance.

[0121] Of course, in other embodiments, the number of reinforcing ribs 314 of the first hoop body 311 and the second hoop body 312 may be the same, or the mechanical strength of the first hoop body 311 may be less than or equal to that of the second hoop body 312 .

[0122] Please also refer to Figure 2 and Figure 3 Furthermore, the landing gear also includes a limit bracket 40, which is mounted on the buffer beam 20 and cooperates with the mounting bracket 30 to limit the lateral displacement of the mounting bracket 30. As such, because the limit bracket 40 is designed to better maintain its mounting position on the buffer beam 20, the limit bracket 40 can prevent the mounting bracket 30 from lateral displacement on the buffer beam 20, thereby maintaining the relative position of the mounting bracket 30 on the buffer beam 20. This maintains the relative lateral position of the aircraft body and the landing gear. Consequently, during different phases, such as takeoff and landing, the landing gear can maintain a balanced force state between the left and right side structures, and avoid the problem of premature failure of one side of the landing gear structure. This improves the installation stability of the mounting bracket 30 and reduces the probability of lateral slippage, thereby improving the safety of the aircraft.

[0123] It should be noted that in the embodiments of the present invention, the transverse direction refers to the left-right direction of the aircraft, the longitudinal direction refers to the front-back direction of the aircraft, and the vertical direction refers to the up-down (vertical) direction of the aircraft. Without loss of generality, the aircraft body and the landing gear are arranged vertically, with the landing gear being located on the underside of the aircraft body. The skid 10 of the landing gear extends generally longitudinally, and the middle portion of the bumper beam 20 extends generally transversely.

[0124] It is understood that there are many ways for the limiting bracket 40 to achieve the limiting cooperation with the mounting bracket 30, for example, see Figure 4In one embodiment, two mounting brackets 30 are spaced apart on the same buffer beam 20, and two corresponding position-limiting brackets 40 are provided and located between the two mounting brackets 30. The position-limiting bracket 40 abuts against the end face of the mounting bracket 30 closest to the other mounting bracket 30. That is, the left position-limiting bracket 40 abuts against the right end face of the left mounting bracket 30, and the right position-limiting bracket 40 abuts against the left end face of the right mounting bracket 30. When the mounting bracket 30 tends to slide to the left, the right position-limiting bracket 40 can prevent such sliding; when the mounting bracket 30 tends to slide to the right, the left position-limiting bracket 40 can prevent such sliding.

[0125] In this way, on the one hand, the landing gear is installed using two spaced-apart mounting brackets 30, which not only improves the installation reliability of the landing gear, but also increases the load transfer path, allowing the landing gear to better absorb energy and provide better shock absorption. On the other hand, only two limit brackets 40 are required to limit the leftward or rightward sliding of the mounting bracket 30, resulting in a simple and easy-to-implement structure and reducing the manufacturing cost of the landing gear. Of course, in other embodiments, four limit brackets 40 may be provided, with each of the opposing end surfaces of a mounting bracket 30 abutting against a limit bracket 40.

[0126] In other embodiments, only one limiting bracket 40 may be provided, and the limiting bracket 40 may be mounted on the mounting bracket 30 by means of bolts, rivets 61, or a snap-fit ​​structure, so as to achieve position-limiting cooperation between the limiting bracket 40 and the mounting bracket 30. In this case, one limiting bracket 40 can simultaneously restrain the mounting bracket 30 from sliding leftward and rightward.

[0127] See also Figure 2 The limiting bracket 40 is configured as a clamp and is arranged around the peripheral side surface of the buffer beam 20. Specifically, the clamp includes two third hoop bodies 41, which are locked and fixed by a pair of bolts and nuts 62, and together surround the peripheral side surface of the buffer beam 20. Specifically, the limiting bracket 40 simply holds the buffer beam 20, so a clamp type with a large friction coefficient can be selected to make it difficult for it to be disturbed by external forces and displaced laterally after holding the buffer beam 20, thereby ensuring the limiting bracket 40's effect of limiting the lateral displacement of the mounting bracket 30. In this way, the limiting bracket 40 has a simple structure and is easy to install and disassemble, and the limiting bracket 40 is installed and fixed on the buffer beam 20 by a clamping method, so there is no need for the buffer beam 20 to have structural designs such as openings, and the good structural strength and mechanical properties of the buffer beam 20 can be maintained.

[0128] Optionally, the nuts 62 used in the two third hoop bodies 41 are slotted nuts, and are fixed circumferentially relative to the bolts using cotter pins 63 to avoid the nuts 62 from loosening or even coming off, thereby improving the installation reliability of the clamp.

[0129] Of course, in other embodiments, the limiting bracket 40 may also be an L-shaped bracket, one side wall of the L-shaped bracket is directly locked to the buffer beam 20 by bolts, and the other side wall abuts against the end face of the mounting bracket 30 .

[0130] It is understood that there are many ways to install the mounting bracket 30 and the buffer beam 20. For example, see Figure 2 and Figure 3 In one embodiment, the mounting bracket 30 has a mounting channel 301 through which the bumper beam 20 is inserted. The landing gear further includes an elastically deformable shock-absorbing pad 70 disposed between the sidewall of the mounting channel 301 and the peripheral side of the bumper beam 20. In other words, the mounting bracket 30 is indirectly mounted to the bumper beam 20 via the shock-absorbing pad 70. In this way, the shock-absorbing pad 70 can play multiple roles. One is the buffering and energy absorption role; the second is to increase the friction between the buffer beam 20 and the mounting bracket 30 to reduce the risk of lateral displacement of the mounting bracket 30; the third is to prevent the buffer beam 20 from being worn due to direct rigid contact with the mounting bracket 30 when the landing gear is deformed and rotated under load, resulting in relative rotation between the buffer beam 20 and the mounting bracket 30, thereby protecting the buffer beam 20 from wear and improving the integrity of the main structure of the landing gear; the fourth is to tolerate the assembly gap between multiple buffer beams 20 and the aircraft body when manufacturing tolerances and assembly tolerances cause the assembly gap to facilitate the assembly and molding of the landing gear and the aircraft body.

[0131] Optionally, the shock-absorbing pad 70 is made of rubber or silicone, and its cushioning performance and supporting stiffness can be adjusted and optimized by adjusting the thickness and material selection of the shock-absorbing pad 70 .

[0132] Of course, in other embodiments, the shock-absorbing pad 70 may not be provided, and the mounting bracket 30 may be directly sleeved on the buffer beam 20 .

[0133] See also Figure 2 A stop flange 313 extends inward from the end surface of the mounting channel 301, and the inner end surface of the stop flange 313 abuts the end surface of the shock-absorbing pad 70. That is, the stop flange 313 is provided at the passage opening of the mounting channel 301, and the shock-absorbing pad 70 is disposed within the mounting channel 301 and is stopped by the stop flange 313, thereby preventing the shock-absorbing pad 70 from falling out of the mounting channel 301. Of course, in other embodiments, the stop flange 313 may not be provided.

[0134] Optionally, a limiting protrusion is provided on the outside of the installation channel 301, and the limiting protrusion abuts against the limiting bracket 40. Figure 2 Alternatively, the stop flange 313 and the stop flange 313 may be configured as the same structure, that is, the outer end surface of the stop flange 313 abuts the stop bracket 40. Thus, by reusing the stop flange 313 as a structure for the stop bracket 40 to abut, this embodiment facilitates simplifying the landing gear structure and reducing its manufacturing cost. Of course, in other embodiments, other structures may be used to abut the stop bracket 40, that is, the stop flange 313 and the stop flange 313 may be different structures.

[0135] It is understood that the mounting bracket 30 has various structural forms, for example, see Figure 2 In one embodiment, the mounting bracket 30 includes a clamp 31, which comprises a first clamp body 311 and a second clamp body 312 connected to each other. The first clamp body 311 and the second clamp body 312 jointly clamp the bumper beam 20 and enable the clamp 31 to rotate about an axis extending in the left-right direction. By releasing the clamp 31's longitudinal rotational freedom, that is, allowing the clamp 31 to rotate about the transverse axis, the bumper beam 20 can bend sufficiently to absorb energy when subjected to an impact load, thereby enhancing the landing gear's energy absorption performance. Of course, in other embodiments, the mounting bracket 30 may also have other structural forms, for example, including a curved plate and a straight plate. The curved plate covers the upper side of the bumper beam 20 and is secured by bolts or rivets 61. The straight plate is located above the curved plate and is secured to the aircraft body by bolts or rivets 61.

[0136] Without loss of generality, during the installation of the aircraft body and the landing gear, the first hoop 311 is usually installed on the lower side of the aircraft body in advance. Then, when the aircraft body is suspended in the air, the landing gear is lifted to be close to the lower side of the aircraft body, and the first hoop 311 is aligned with its installation position area on the buffer beam 20. The second hoop 312 is then buckled onto the lower side of the buffer beam 20 and aligned with the first hoop 311. Finally, the second hoop 312 is locked to the first hoop 311 using a pair of bolts and nuts 62, thereby completing the installation and fixing operation of the landing gear on the aircraft body.

[0137] It is understandable that how to prompt the first hoop body 311 to quickly and accurately align its installation position area on the buffer beam 20 can be achieved in a variety of ways, for example, a positioning line segment or a positioning wire frame can be engraved on the buffer beam 20, or during the alignment process of the first hoop body 311, the area can be located on the buffer beam 20 by irradiating a laser beam.

[0138] It is worth mentioning that in the embodiment where two limiting brackets 40 are provided and respectively abut the inner end surfaces of the two mounting brackets 30 (i.e., the end surfaces of the two mounting brackets 30 facing each other), before the hoop 31 is assembled, since the limiting bracket 40 has been accurately installed on the buffer beam 20 in advance, the limiting bracket 40 can play a positioning role. Specifically, during the process of assembling the main structure of the landing gear (including the skid 10 and the buffer beam 20) using a fixture, the limiting bracket 40 can be further accurately installed on the buffer beam 20 using laser positioning or other means. When the subsequent aircraft body and the first hoop body 311 thereon fall on the buffer beam 20, the first hoop body 311 is placed on the edge of the limiting bracket 40, so that the first hoop body 311 can be quickly and accurately aligned with its installation position area on the buffer beam 20.

[0139] As can be seen, the embodiment of the present invention utilizes the position-limiting bracket 40 to facilitate the installation and positioning of the clamp 31. Compared to the method of engraving positioning lines or a positioning frame on the buffer beam 20, this method can save the production process of engraving positioning lines or a positioning frame on the buffer beam 20, and the positioning area can be more easily identified by the naked eye. Furthermore, compared to the method of irradiating the buffer beam 20 with a laser beam during the alignment of the first clamp body 311, this method can save the laser alignment operation at this stage, thereby simplifying the assembly of the landing gear and the aircraft body and overcoming the problem of poor positioning accuracy caused by changes in the positioning reference.

[0140] It is worth mentioning that the clamp 31, limit bracket 40 and anti-wear plate 80 of the landing gear of the present invention are all replaceable units to achieve the design purpose of LRU (Line Replaceable Unit), thereby making the maintenance of the landing gear more convenient and shortening the maintenance cycle.

[0141] The present invention further provides an aircraft comprising an aircraft body and landing gear. The specific structure of the landing gear is similar to that of the aforementioned embodiments. Since the present aircraft utilizes all of the technical solutions of all of the aforementioned embodiments, it possesses at least all of the beneficial effects brought about by the technical solutions of the aforementioned embodiments, and therefore will not be further detailed here. The landing gear is disposed on the underside of the aircraft body.

[0142] Optionally, the aircraft may be an eVTOL (Electric Vertical Take off and Landing) electric vertical take-off and landing aircraft, or a helicopter, etc., and this application does not make any specific limitations on this.

[0143] The present invention further provides a landing gear design method, which includes steps S110 to S140, specifically as follows:

[0144] Step S110: constructing an initial wireframe model of the landing gear.

[0145] First, formulate an initial plan for the overall layout of the landing gear. The external constraints of the landing gear design can be determined first. The position of the landing gear skid is determined according to the aircraft's take-off, landing, and parking requirements. The height position of the buffer beam and its relative position on the skid are determined based on the position area on the aircraft body used for connection to the landing gear.

[0146] In this embodiment, the initial wireframe model of the landing gear includes two skids and two buffer beams, wherein the buffer beam is connected between the two skids and is arranged to protrude upward, the two buffer beams are distributed in the front-to-back direction, and the two skids are distributed in the left-to-right direction; the buffer beam includes a transverse beam section and a curved beam section, and the curved beam section is connected between the transverse beam section and the skids.

[0147] Without loss of generality, the overall layout parameters of the landing gear are mainly:

[0148] (a) Parking angle φ: the angle between the longitudinal axis of the aircraft and the parking surface when the aircraft is parked;

[0149] (b) Longitudinal span b: the longitudinal length of the line formed by all the ground contact points of the skid;

[0150] (c) Transverse span B: the transverse distance between the left and right skids;

[0151] (d) Minimum distance of structure from the ground h0: the distance from the lowest point of the aircraft fuselage to the ground;

[0152] (e) Height of center of gravity above the ground, h: the distance above the ground when the landing gear is in contact with the ground and not compressed;

[0153] (f) Rear cowl angle β: The angle between the plane formed by the center of gravity of the aircraft and the rear contact points of the left and right skids and the vertical plane at the center of gravity when the aircraft is parked;

[0154] (g) Front cowl angle γ: The angle between the plane formed by the center of gravity of the aircraft and the front contact points of the left and right skids and the vertical plane of the center of gravity when the aircraft is parked;

[0155] (h) Side shroud angle ε: the angle between the plane formed by the center of gravity and the front and rear contact points of the skid and the vertical to the center of gravity when the machine is stopped;

[0156] (i) Autorotation landing angle θ: The angle between the landing gear and the landing surface when the landing gear is uncompressed and the plane passing through the rear contact point of the skid and the tail strut.

[0157] To maintain a nearly horizontal aircraft attitude during forward flight, the propeller plane is often tilted forward at a certain angle, γ, rather than parallel to the horizontal plane of the aircraft. However, when the aircraft is parked, the propeller shaft's tilt creates a forward thrust, causing the aircraft to glide forward. To prevent this, the aircraft is tilted backward at a certain angle during parking to reduce or even offset the forward thrust generated by the propellers. The angle at which the aircraft tilts backward during parking is called the parking angle. The parking angle φ ranges from 0 ≤ φ ≤ γ. Excessively large backward angles can cause the horizontal component of the propeller thrust to be directed backward, causing the aircraft to glide backward. For example, a parking angle φ of 2° can be used.

[0158] The greater the minimum ground clearance h0, the greater the distance between the lowest point of the aircraft fuselage and the ground when it makes contact, effectively preventing the aircraft fuselage from contacting or even colliding with protruding objects on the ground. However, the minimum ground clearance h0 also affects the values ​​of other overall layout parameters (such as the rear cowl angle β, the side cowl angle ε, and the longitudinal span b). Therefore, h0 should not be too large, otherwise it will lead to the adverse effects of excessive landing gear height and excessive weight. For example, the range of h0 can be 150mm < h0 < 500mm.

[0159] The position of the center of gravity of an aircraft has a profound impact on the overall layout of the landing gear. The center of gravity position is marked on the fuselage. The height of the center of gravity above the ground is h = the minimum distance of the structure from the ground h0 + the height of the center of gravity from the lowest point of the fuselage h1.

[0160] See also Figure 9 According to the design specifications of the skid landing gear, the range of the front and rear shroud angles γ and β is 30° to 40°. Therefore, two lines L1 and L2 can be drawn through the center of gravity of the aircraft, forming angles of 30° and 40° with the vertical direction, and then a circle with a diameter of 150mm can be drawn through the point where the tail strut touches the ground when the aircraft flips backward (such as Figure 8 (Indicated by the dotted circle above the rear of the landing gear in the figure, two tangent lines are drawn through the intersection of L1 and L2 with the ground and this circle to determine the range of values ​​for the autorotation landing angle θ. Due to weight control requirements for the aircraft, the skids are preferably as short as possible. Therefore, the initial value of the autorotation landing angle θ can be set to 30°.

[0161] See also Figure 6 Another constraint on the landing gear design is the value of the side cover angle ε. To prevent the aircraft from rolling over, the side cover angle ε cannot be too small. Take a left rollover as an example. At the moment of the rollover, the right skid just leaves the ground, and only the left skid touches the ground. At this time, the forces acting on the aircraft are as follows: the gravity G acting on the aircraft, the support force N, friction force f, and inertia force P provided by the ground on the left skid. The inertia force P and the friction force f constitute the rollover moment, and the gravity G and the support force N constitute the restoring moment. To prevent the aircraft from rolling over, it is necessary to ensure that the restoring moment is greater than the rollover moment, that is, the following equations ① and ② need to be satisfied:

[0162] Gx>fh formula ①

[0163]

[0164] Here, x refers to the distance from the center of gravity of the aircraft to the point where the main wheels touch down, and this distance affects the aircraft's restoring moment. The size of the side cover angle ε represents the aircraft's ability to prevent rollovers. As can be seen from the above formula, the lower the aircraft's center of gravity, the greater the lateral spacing between the left and right skids, the larger the side cover angle ε, and the better the rollover prevention capability. The coordinates of the aircraft's center of gravity are given by the aircraft as a whole and cannot be significantly changed during the landing gear design. In addition, due to the drag and weight restrictions of the aircraft fuselage, the lateral span B between the left and right skids cannot be too large. The smallest lateral span possible should be selected within the range that meets the rollover prevention requirements. Typically, the side cover angle ε is 30° to 40°, which provides the range of values ​​for the lateral span B. Usually, to ensure weight and wind resistance, the lateral span B can be initially calculated as 30°.

[0165] After determining the values ​​of the front shroud angle γ and the rear shroud angle β, the longitudinal span b can be determined.

[0166] After developing an initial plan for the overall landing gear layout, the locations of the fuselage mounting points on the bumper beam need to be determined. Without loss of generality, two fuselage mounting points are typically spaced apart on the same bumper beam, and these two fuselage mounting points are typically located at opposite ends of the bumper beam's transverse and vertical beam sections. That is, in this embodiment, two fuselage mounting points are located at opposite ends of the transverse and vertical beam sections, with a spacing d between the two fuselage mounting points. It will be appreciated that the value of this spacing d is positively correlated with the length of the transverse and vertical beam sections. That is, the longer the transverse and vertical beam sections, the larger the allowable value of spacing d, and vice versa.

[0167] It should be noted that the aircraft body usually includes a fuselage and a propeller installed on the fuselage. The fuselage is installed above the buffer beam and has a crew cabin for the pilot and passengers. The fuselage mounting point in this embodiment refers to the installation position of the fuselage on the buffer beam, and the landing gear mounting bracket mentioned above is installed at the location of the fuselage mounting point.

[0168] Step S120: constructing a primary simulation model of the landing gear based on the initial wireframe model, and performing mechanical analysis and modal analysis.

[0169] The mechanical analysis includes static analysis and dynamic simulation analysis to respectively verify the static performance and dynamic performance of the primary simulation model of the landing gear. The static analysis can be performed before the dynamic simulation analysis.

[0170] It's worth noting that when constructing the primary simulation model of the landing gear, the connection between the skid and the bumper beam can optionally be simulated as a common-node connection. This significantly reduces the computational complexity of computer simulation analysis, allowing for rapid identification of landing gear design optimization strategies and shortening the landing gear design cycle.

[0171] Understandably, when a skid-type landing gear is subjected to an aircraft's impact dynamic load, the skid and the buffer beam work together to absorb landing energy. To absorb this energy, the desired landing gear deformation is as large as possible. However, due to the material's elastic modulus, material deformation exceeding a certain limit will result in irreversible plastic deformation. Therefore, it is desirable for the material to deform within the elastic range. This necessitates finding a boundary condition for landing gear deformation that maximizes the material's deformation without causing plastic deformation. This objective can be achieved through iterative optimization based on the results of mechanical analysis.

[0172] The bumper beam's transverse and curved sections are both capable of elastic deformation, absorbing energy. The elastic deformation and energy absorption efficiency of these sections are closely related to the location of their fuselage mounting points. In other words, the placement of the fuselage mounting points determines the energy absorption distribution ratio and elastic deformation of the two sections. To ensure that one section significantly absorbs more energy than the other, the length of the transverse and curved sections should be neither too long nor too short.

[0173] Secondly, if the bumper beam has a large curved section, that is, if the curved section has a large bending radius, the length of the horizontal and vertical sections in the middle of the bumper beam will be correspondingly shorter, resulting in a shorter distance d between the two fuselage mounting points, which in turn increases the risk of fuselage resonance. Therefore, this embodiment also incorporates modal analysis to prevent the vibration frequencies of the landing gear and the fuselage from being too close, thereby ensuring that the fuselage and landing gear do not resonate at the same frequency during aircraft landing. In other words, the results of modal analysis are used to determine the appropriate value of the distance d to reduce the risk of fuselage resonance.

[0174] If the results of the mechanical analysis and modal analysis of the primary simulation model both meet the requirements, step S121 is executed: determining that the primary simulation model is qualified.

[0175] If not, that is, if either the drop simulation analysis result or the static performance of the landing gear secondary simulation model does not meet the requirements, step S122 is executed: optimizing the primary simulation model iteratively until the analysis result meets the requirements.

[0176] Step S130: determining the value of the distance d according to a qualified primary simulation model.

[0177] After analysis, it was found that the ratio of the distance d to the landing gear width D is more reasonable between 30% and 70%, and more optimally between 45% and 50%. In other words, 0.3≤d / D≤0.7, for example, d / D is 0.45 or 0.5.

[0178] In this way, by maximizing the spacing d, that is, maximizing the distance between the two mounting brackets 30 located on the same buffer beam 20, on the one hand, the length of the deformable portion in the middle of the buffer beam 20 (i.e., the transverse and vertical beam sections) can be increased, which is beneficial to improving the buffering and energy absorption effect of the landing gear; on the other hand, the vibration amplitude of the aircraft body can be reduced, thereby making the posture of the aircraft body more stable, and it is also beneficial to avoid resonance between the landing gear and the fuselage.

[0179] In the second embodiment of the design method, based on the solution of the first embodiment of the design method, the landing gear design method further includes steps S140 and S150:

[0180] Step S140: constructing a secondary simulation model of the landing gear based on the primary simulation model and the connection structure connecting the skid and the buffer beam; wherein the bending radius of the bending beam section of the secondary simulation model is R G ;

[0181] Step S150: Performing a drop simulation analysis on the secondary simulation model to determine the minimum bending radius R of the curved beam segment. Gm ; Wherein, the bending radius R G Greater than the minimum bending radius R Gm .

[0182] As mentioned above, both the horizontal and vertical beam sections and the curved beam sections of the buffer beam can elastically deform to absorb energy. On the basis of the spacing d (equivalent to the length of the horizontal and vertical beam sections), the bending radius R of the curved beam section needs to be further determined. G .

[0183] The bending radius R G As long as the value is greater than the minimum bending radius R Gm , it can ensure that the curved beam section can still maintain structural effectiveness when the landing gear is subjected to the maximum load, and on this basis play its role in elastic deformation and energy absorption.

[0184] That is, the minimum bending radius R Gm , which means that under the premise that other structural parameters are the same, when the bending radius of the curved beam segment is less than or equal to the minimum bending radius R Gm When the landing gear is in the drop simulation analysis stage, it is unable to maintain the effectiveness of the structure, for example, the structural failure occurs at the bending beam section.

[0185] In addition to the aforementioned drop simulation analysis, a deformation coordination analysis can also be performed. Specifically, a deformation coordination analysis is performed on landing gear structures that meet static strength requirements. This involves performing static strength simulations of the front and rear beams under gravity and overload loads within the aircraft's forward and rearward center of gravity limits. The vertical deformation of the landing gear at the four fuselage mounting points remains consistent. If the design parameters of the front and rear beams do not meet the load-deformation coordination constraints, the design parameters (including geometric parameters) of the landing gear structure can be adjusted and the aforementioned deformation coordination analysis repeated until the landing gear structure meets the goal of consistent deformation coordination between the front and rear beams.

[0186] In this way, it can be ensured that the deformation of the front and rear beams of the landing gear is coordinated and consistent while meeting the static strength requirements, so that the front and rear deformations and the left and right deformations of the landing gear are consistent, and the rollover moment (such as the side rollover moment or the back rollover moment) is smaller than the restoring moment, thereby avoiding the overturning of the aircraft.

[0187] In the third embodiment of the design method, the rear end of the sled has a rear warping section, and based on the solution of the second embodiment of the design method, the sled of the secondary simulation model is provided with a rear warping section at the rear end, and the bending radius of the rear warping section is R R ;

[0188] The step of performing drop shock simulation analysis on the secondary simulation model is also used to determine the minimum unyielding radius R of the rear warping section of the landing gear when the landing gear is flipped over and landed. Rm ; Wherein, the bending radius R R Greater than the minimum unyielding radius R Rm .

[0189] The bending radius R R As long as the value is greater than the minimum unyielding radius R Rm , it can ensure that when the rear end of the skid is subjected to the maximum load, for example, when the landing gear is turned over for landing, the structure can still maintain its effectiveness and, on this basis, play its role in absorbing energy through elastic deformation.

[0190] That is, the minimum unyielding radius R Rm , which means that under the premise that other structural parameters are the same, when the bending radius of the post-warping section is less than or equal to the minimum unyielding radius R Rm When the landing gear is under test, it is unable to maintain the effectiveness of the structure during the drop simulation analysis phase, for example, structural failure occurs at the rear warping section.

[0191] In this embodiment, the rear end of the skid should touch down at a point where the aircraft's rollback angle is smaller than the rear cover angle to prevent the aircraft from rolling back when landing. In order to prevent the tail support of the aircraft from being damaged when landing at the maximum rollback angle, the rear warping section (i.e., the rearward-bent section of the skid's rear end) coincides with the anti-rollback angle line, and the bending radius R of the rear warping section is 1 / 4 of the width of the rear warping section. R It must be larger than the minimum unyielding radius R obtained by the drop shock simulation when the aircraft is later flipped over and landed. Rm .

[0192] In the fourth embodiment of the design method, the front end of the slide has a front warping section, and based on the solution of the third embodiment of the design method, the slide of the secondary simulation model has a front warping section at the front end, and the bending radius of the front warping section is R F ;

[0193] The step of performing drop simulation analysis on the secondary simulation model is also used to determine the minimum bending radius R of the front warping section. Fm ; Wherein, the bending radius R F Greater than the minimum bending radius R Fm .

[0194] The bending radius R F As long as the value is greater than the minimum bending radius R Fm , it can ensure that when the front end of the skid is subjected to the maximum load, for example, when the landing gear lands at a forward roll angle, the structural effectiveness can still be maintained, and on this basis, its elastic deformation energy absorption function can be exerted.

[0195] That is, the minimum bending radius R Fm , which means that under the premise that other structural parameters are the same, the bending radius of the current warping segment is less than or equal to the minimum bending radius R Fm When the landing gear is under test, it is unable to maintain the effectiveness of the structure during the drop simulation analysis phase, for example, structural failure occurs at the front warping section.

[0196] In this embodiment, the bending radius of the front warping section of the skid and the bending beam section of the buffer beam are determined by using the drop shock simulation method. The landing gear should first meet the overall layout requirements. Then, under the premise of ensuring that the landing gear skid and the buffer beam meet the static strength requirements and landing load, the minimum bending radius (including R Gm and R Fm ).

[0197] On this basis, to facilitate the connection between the front warped section of the sled and the curved beam section of the front beam, a first joint is provided between the two, with a straight pipe section corresponding to the first joint. In other words, a straight pipe section extends from the front end of the front warped section and the rear end of the curved beam section, and these two straight pipe sections are inserted and fixed into the first joint. Therefore, when determining the bending radius of the front warped section and the curved beam section of the front beam, the length of the straight pipe sections at the ends of these two sections must also be considered to ensure that there is sufficient linear distance between the sled and the front beam to install the first joint.

[0198] It can be understood that the structural form of the slide and the buffer beam can be basically determined through the above steps. For example, taking the slide as an example, the longitudinal span b of the slide can be determined through the overall layout step. Then, the bending radius of the front warping section of the slide can be determined through the step of performing a drop shock simulation analysis on the secondary simulation model. Then, the front end boundary of the front warping section can be determined through the height of the front beam from the ground and the joint length of the first joint. In this way, the starting position, end position and bending radius of the front warping section can be determined one by one.

[0199] The structure corresponding to the bending radius in the above-mentioned design method embodiment can be realized by a bending process, or by a process such as stamping or die-casting.

[0200] Of course, in the embodiment where the structures of the buffer beam or the slide corresponding to the above-mentioned multiple bending radii are all realized by a bending process, optionally, the bending radius is R G , bending radius R R and bending radius R F The value configuration is the same.

[0201] That is, specifically optionally, in the fifth embodiment of the design method, based on the solution of the fourth embodiment of the design method, the bending radius R G , bending radius R R and bending radius R F The value of is the same and is greater than the minimum bending radius R Gm , minimum unyielding radius R Rm and minimum bending radius R Fm That is, the minimum bending radius R is calculated in the above steps. Gm , minimum unyielding radius R Rm and minimum bending radius R Fm Finally, any one of the three needs to be smaller than the value of the bending radius of the buffer beam and the slider, so that the bending structures on the buffer beam and the slider can meet the performance requirements.

[0202] In this way, by unifying the bending radius on the buffer beam and the slide, on the one hand, in embodiments where these bending structures are realized by a bending process, the development cost of the bending mold can be reduced; on the other hand, the parameter design of the factors that need to be considered in the design method steps can be simplified, and the design efficiency can be improved and the design cost can be reduced.

[0203] Furthermore, by making the bending radius of all the curved structures of the skid and the buffer beam consistent, the low-cost design goal can be further achieved. The above-mentioned design steps can all be configured to be performed based on this design principle.

[0204] In a sixth embodiment of the design method, based on the solution of the fourth embodiment of the design method, the step of performing a drop simulation analysis on the secondary simulation model is further used to obtain stress results of the landing gear and absorption results of the multi-stage energy absorbing structure, and determine whether the secondary simulation model is qualified based on the stress results and absorption results;

[0205] Among them, the multi-level energy absorption structure includes a first-level absorption structure formed by the bending deformation of the horizontal beam section, a second-level absorption structure formed by the bending deformation of the curved beam section, and a third-level absorption structure formed by the bending deformation of the front warping section. The energy absorption amount of the first-level absorption structure is E1, the energy absorption amount of the second-level absorption structure is E2, and the energy absorption amount of the third-level absorption structure is E3.

[0206] In this embodiment, the landing gear has a multi-stage energy absorption structural characteristic, such as Figure 1 As shown, the horizontal and vertical beam sections of the buffer beam absorb the first level of energy E1 by releasing the bending freedom and deforming, the bending deformation of the curved beam section of the buffer beam absorbs the second level of energy E2, the bending deformation of the front warping section of the slide absorbs the third level of energy E3, and the friction between the anti-wear plate and the ground absorbs the fourth level of energy E4, among which E1, E2 and E3 are interrelated.

[0207] Optionally, in this embodiment, the landing gear further includes an anti-wear plate provided on the lower side of the skid. The friction between the anti-wear plate and the ground can form a fourth-level absorption structure, and the energy absorption amount of the fourth-level absorption structure is E4.

[0208] In this embodiment, after the static strength analysis satisfies the deformation coordination conditions, a drop simulation analysis is performed to obtain analysis results such as landing gear stress, energy absorption at each level (including E1 to E4), and overload. This provides a basis for evaluating the landing gear performance and thus determines whether the landing gear design meets the requirements. If it does not meet the requirements, repeated analysis and verification can be performed by adjusting relevant structural parameters.

[0209] Among them, if the energy absorption capacity of the first-level absorption structure needs to be adjusted, the spacing d, the pipe diameter and wall thickness of the buffer beam, etc. can be adjusted; if the energy absorption capacity of the second-level absorption structure needs to be adjusted, the pipe diameter and wall thickness of the buffer beam, the bending radius and length of the curved beam section, etc. can be adjusted; if the energy absorption capacity of the third-level absorption structure needs to be adjusted, the pipe diameter and wall thickness of the front warping section of the slide, the bending radius and length of the front warping section, etc. can be adjusted; if the energy absorption capacity of the fourth-level absorption structure needs to be adjusted, the material, wall thickness, contact area with the ground, etc. of the anti-wear plate can be adjusted.

[0210] Understandably, landing gear landing is a multi-parameter coupled process, where landing performance depends on multiple objectives, including the kinematic and dynamic performance of the mounting bracket, bumper beam, and skid. These objectives are often conflicting, and achieving optimal performance for each metric simultaneously is a significant challenge. Multi-objective optimization of the landing gear landing process requires coordinating each metric to achieve the optimal level possible. This involves optimizing the objective function setting and problem solving, and considering the comprehensive benefits of landing gear landing performance under these multiple objectives.

[0211] In the field of multi-objective optimization design, a large number of studies have shown that when dealing with multi-objective optimization problems, the most direct and effective method is to convert each objective into a single-objective problem by setting importance weights, but the choice of weights has a great impact on the final optimization results.

[0212] A method for converting multiple objectives into a single objective using linear weighting can be used to make objective decisions more biased. A genetic algorithm is used to optimize landing gear landing performance. First, a dynamic model of landing gear landing is established. The sensitivity of each model parameter to each optimization indicator is calculated. Based on this sensitivity, the landing gear design parameters are determined. A multi-objective model for landing gear parameters is established using a comprehensive weighting method and a subjective and objective weighting method. The overall benefit is used as the fitness function in the genetic algorithm, and the landing gear parameter combination that achieves the optimal overall benefit is ultimately determined.

[0213] The parameters involved in the multi-objective optimization of the present invention include, but are not limited to, the landing gear's wind resistance, weight, strength, stiffness, energy absorption efficiency, and overall layout. Based on these parameters, an iterative design process is performed to achieve the optimal solution. The relevant design analysis is relatively mature, so it will not be elaborated on here.

[0214] In the seventh embodiment of the design method, based on the solution of the first embodiment of the design method, step S120 specifically includes steps S121 to S127:

[0215] Step S121: constructing a one-dimensional beam unit model of the landing gear based on the initial wireframe model of the landing gear, and performing static performance analysis;

[0216] If the static performance of the one-dimensional beam element model does not meet the requirements, perform the following steps:

[0217] Step S122: Optimize and iterate the one-dimensional beam element model until the one-dimensional beam element model meets the static performance requirements;

[0218] If the static performance of the one-dimensional beam element model meets the requirements, perform the following steps:

[0219] Step S123, performing dynamic simulation analysis on the one-dimensional beam element model;

[0220] If the dynamic performance of the one-dimensional beam element model does not meet the requirements, perform the following steps:

[0221] Step S124, optimizing and iterating the one-dimensional beam element model until the one-dimensional beam element model meets the dynamic performance requirements;

[0222] If the dynamic performance of the one-dimensional beam element model meets the requirements, perform the following steps:

[0223] Step S125: constructing a two-dimensional shell element model of the landing gear based on the one-dimensional beam element model, and performing static analysis;

[0224] If the static performance of the two-dimensional shell element model does not meet the requirements, perform the following steps:

[0225] Step S126: Optimize and iterate the two-dimensional shell element model until the two-dimensional shell element model meets the static performance requirements;

[0226] If the static performance of the two-dimensional shell element model meets the requirements, perform the following steps:

[0227] Step S127: output the corresponding two-dimensional shell element model as a qualified landing gear primary simulation model.

[0228] In this embodiment, when constructing the primary simulation model of the landing gear, two versions of the finite element model were used, one for scheme design and the other for parameter design. Specifically, the scheme design model is entirely composed of one-dimensional beam units, and the connections between the parts adopt a common node method, which can be quickly iterated and changed, and has high computational efficiency. The parameter design model is based on the preliminary structural model to establish a more detailed two-dimensional shell unit model, and the connections between the parts still adopt a common node method. Among them, when the one-dimensional beam unit model is optimized and iterated based on the static analysis results until it meets the requirements, the force transmission path of the structure can be optimized and the stress concentration of the structure can be reduced; when the one-dimensional beam unit model is optimized and iterated based on the dynamic simulation results until it meets the requirements, it is necessary to pay attention to the natural mode and impact response of the structure; when the two-dimensional shell unit model is optimized and iterated based on the static analysis results, it is necessary to pay attention to the stress distribution of the parts under the working conditions and determine the structural detail parameters such as the diameter of the tube and the wall thickness.

[0229] In this embodiment, the connection structure between the skid and the bumper beam (including the first and second joints, etc.) is simplified to a common-node connection in the primary simulation model of the landing gear. A preliminary simulation analysis is then performed to clarify the landing gear's structural form. If the mechanical properties of the primary simulation model meet the requirements, the connection structure is further refined and simulated and analyzed to clarify its specific structure. This significantly reduces the computational complexity of the computer simulation analysis, quickly identifies design optimization strategies for the landing gear, and shortens the landing gear design cycle.

[0230] It should be pointed out that the above-mentioned design steps including static strength analysis and drop simulation analysis can be implemented, but not limited to, through software.

[0231] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformation made by utilizing the contents of the present invention's description and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A landing gear, characterized in that: include: Two slides, the two slides are arranged opposite to each other; Two buffer beams, each of which connects the two slides and protrudes upward, each of which has an elastically deformable transverse beam section and two curved beam sections, each of which is connected between the transverse beam section and the slide; and Four mounting brackets, each used to connect to the aircraft body; the two buffer beams include a front beam and a rear beam; the transverse and vertical beam sections of the front beam and the rear beam are each provided with two mounting brackets; the two mounting brackets are located at opposite ends of the same transverse and vertical beam section, and the spacing between the two mounting brackets is d; the width of the landing gear in the distribution direction of the mounting brackets is D, and 0.3≤d / D≤0.7; the rear beam is located near the center of gravity of the aircraft, and the d / D value on the rear beam is smaller than the d / D value on the front beam; The landing gear further includes a limit bracket, which is provided on the buffer beam and cooperates with the mounting bracket to limit the lateral displacement of the mounting bracket; There are two limit brackets, which are located at the interval between the two mounting brackets on the same buffer beam, and the limit bracket abuts against the end face of the mounting bracket close to the other mounting bracket; and / or, the limit bracket is configured as a clamp and is arranged on the peripheral side surface of the buffer beam.

2. The landing gear according to claim 1, wherein: The curved beam section of the front beam is bent outward and extends toward the rear and side, and is butted against the front end of the skid.

3. The landing gear according to claim 2, characterized in that The front end of the slide has a front warping section extending upward toward the front, the front warping section protruding outward and connected to the curved beam section of the front beam; the rear end of the slide has a rear warping section extending upward toward the rear, and the radii of the rear warping section, the front warping section and the curved beam section are configured to be the same.

4. The landing gear according to claim 2, wherein: The landing gear also includes a first joint, and the front beam and the slide are respectively inserted at opposite ends of the first joint; the front beam and / or the slide are fixedly connected to the first joint via a connecting member, and / or the ratio of the depth of the front beam inserted into the first joint to the diameter of the front beam is in a range of 1 to 2, and / or the ratio of the depth of the slide inserted into the first joint to the diameter of the slide is in a range of 1 to 2.

5. The landing gear according to claim 1, wherein: The material of the buffer beam is spring steel, and the material of the slide is deformed aluminum alloy; And / or, the buffer beam and / or the skid is a tubular structure, and the cross-section is circular, elliptical or polygonal; And / or, the landing gear further comprises an anti-wear sheet, wherein the anti-wear sheet is provided on the lower side of the skid; And / or, the landing gear further comprises a second joint, the second joint being provided with an insertion hole and a buckle groove, the end portion of the rear beam being inserted into the insertion hole and fixed by bolts, and the buckle groove being buckled on the upper side of the skid and fixed by rivets.

6. The landing gear according to claim 1, wherein: The mounting bracket includes a mounting seat and a stop structure, wherein the mounting seat is connected to the aircraft body, and the stop structure connects the mounting seat and the buffer beam to limit the mounting seat from being separated from the buffer beam in the vertical direction; The side wall of the mounting seat is provided with a relief groove with the notch facing downward, and the anti-slip structure includes an anti-slip boss, a mounting boss and a locking piece. The anti-slip boss extends outward from the notch edge of the relief groove, and the mounting boss is installed on the buffer beam. The relief groove can be sleeved on the mounting boss from top to bottom, and the locking piece is detachably installed on the mounting boss and abuts against the upper side of the anti-slip boss.

7. The landing gear according to claim 6, characterized in that The mounting boss is a stud, and the locking member includes a nut and a locking washer. The nut is locked on the mounting boss and the locking washer is clamped on the mounting seat. The locking washer abuts against the upper side of the locking boss. And / or, the nut is a slotted nut, and the slotted nut is fixed relative to the stud in the circumferential direction by a cotter pin; And / or, a connecting gap between the nut and the stud is filled with protective glue.

8. The landing gear according to claim 1, wherein: The mounting bracket further includes a hoop, the hoop including a first hoop body and a second hoop body connected to each other, the first hoop body and the second hoop body jointly clamping the buffer beam and enabling the hoop to rotate around an axis extending in the left-right direction; the first hoop body is provided above the second hoop body and is used to connect to the aircraft body; and / or, the mechanical strength of the first hoop body is greater than that of the second hoop body; And / or, the first hoop body and the second hoop body are provided with reinforcing ribs, and the reinforcing ribs surround the outer peripheral surface of the clamp along the front-to-back direction of the landing gear. The number of reinforcing ribs on the first hoop body is greater than the number of reinforcing ribs on the second hoop body, and the multiple reinforcing ribs on the first hoop body are arranged along the left-right direction of the landing gear.

9. The landing gear according to claim 1, wherein: The mounting bracket has a mounting channel, the buffer beam is passed through the mounting channel, a stop flange is extended inwardly from the end surface of the mounting channel, and the outer end surface of the stop flange abuts against the limit bracket.

10. The landing gear according to any one of claims 1 to 9, characterized in that The mounting bracket has a mounting channel, the buffer beam is inserted into the mounting channel, and the landing gear further includes an elastically deformable shock-absorbing pad, the shock-absorbing pad being disposed between a side wall of the mounting channel and a peripheral side surface of the buffer beam; a stop flange extends inwardly from an end surface of the mounting channel, and an inner end surface of the stop flange abuts against an end surface of the shock-absorbing pad; and / or, 0.45≤d / D≤0.

5.

11. A landing gear design method, characterized in that: Applied to the design of a landing gear according to any one of claims 1 to 10, the landing gear design method comprises the steps of: Constructing an initial wireframe model of the landing gear; wherein the initial wireframe model includes two skids of the landing gear and a buffer beam connected between the two skids, the buffer beam including a transverse beam section and a curved beam section, the curved beam section connected between the transverse beam section and the skids, two fuselage mounting points being provided at opposite ends of the transverse beam section, and the distance between the two fuselage mounting points being d; Constructing a primary simulation model of the landing gear based on the initial wireframe model, and performing mechanical analysis and modal analysis; If the results of the mechanical analysis and modal analysis of the primary simulation model meet the requirements, the primary simulation model is judged to be qualified; If not, the primary simulation model is optimized and iterated until the analysis results meet the requirements; The value of the distance d is determined based on a qualified primary simulation model.

12. The landing gear design method according to claim 11, wherein: The landing gear design method further comprises the steps of: According to the primary simulation model and the connection structure between the skid and the buffer beam, a secondary simulation model of the landing gear is constructed; wherein the bending radius of the curved beam section of the secondary simulation model is R G ; Perform drop simulation analysis on the secondary simulation model to determine the minimum bending radius R of the curved beam segment. Gm ; Wherein, the bending radius R G Greater than the minimum bending radius R Gm .

13. The landing gear design method according to claim 12, wherein: The skid of the secondary simulation model is provided with a rear warping section at the rear end, and the bending radius of the rear warping section is R R The step of performing drop shock simulation analysis on the secondary simulation model is also used to determine the minimum unyielding radius R of the rear warping section of the landing gear when the landing gear is later turned over and landed. Rm ; Wherein, the bending radius R R Greater than the minimum unyielding radius R Rm ; And / or, the skid of the secondary simulation model is provided with a front warping section at the front end, and the bending radius of the front warping section is R F The step of performing drop simulation analysis on the secondary simulation model is also used to determine the minimum bending radius R of the front warping section Fm ; Wherein, the bending radius R F Greater than the minimum bending radius R Fm .

14. The landing gear design method according to claim 13, wherein: The bending radius R G , bending radius R R and bending radius R F The value of is the same and is greater than the minimum bending radius R Gm , minimum unyielding radius R Rm and minimum bending radius R Fm The largest one among them.

15. The landing gear design method according to claim 13, wherein: The step of performing a drop shock simulation analysis on the secondary simulation model is further used to obtain stress results of the landing gear and absorption results of the multi-stage energy absorption structure, and determine whether the secondary simulation model is qualified based on the stress results and absorption results; Among them, the multi-level energy absorption structure includes a first-level absorption structure formed by the bending deformation of the horizontal beam section, a second-level absorption structure formed by the bending deformation of the curved beam section, and a third-level absorption structure formed by the bending deformation of the front warping section. The energy absorption amount of the first-level absorption structure is E1, the energy absorption amount of the second-level absorption structure is E2, and the energy absorption amount of the third-level absorption structure is E3.

16. An aircraft, characterized in that: The invention comprises an aircraft body and the landing gear according to any one of claims 1 to 10, wherein the landing gear is arranged on the lower side of the aircraft body.

Images