An adaptive damping structure for an aircraft landing gear strut

Abstract

The application relates to the technical field of aviation equipment, and discloses a self-adaptive damping structure of an airplane landing gear buffer strut, which comprises a bottom plate, a stand, a sliding plate, a leaf spring, a wheel, a winch and a winch rope. The self-adaptive damping structure of the airplane landing gear buffer strut can make the convex block on the top rod move along the spiral groove in the inner side of the winch when the sliding plate moves upward under the action of the force of the wheel, drive the winch to wind the winch rope, and form a same-direction pre-bending corresponding to the upward moving amount by pulling the leaf spring through the positioning block. The self-adaptive damping structure of the airplane landing gear buffer strut can make the elastic recovery force generated by the leaf spring act on the sliding plate through the cooperation of the positioning block, the winch rope, the winch and the convex block in the spiral groove, and continue to move the sliding plate upward to form a feedback resistance. Therefore, the leaf spring can retain the corresponding elastic deformation capacity under the premise of meeting the support requirements of different loads, and the damping stability in the landing and sliding process is improved.

Description

Technical Field

[0001] This invention relates to the field of aviation equipment technology, and in particular to an adaptive vibration reduction structure for an aircraft landing gear buffer strut. Background Technology

[0002] Aircraft landing gear supports the fuselage during landing and taxiing, and reduces the impact load generated when the wheels contact the ground. Currently, some small, light sport aircraft use leaf springs as shock absorbers in their landing gear. Compared to hydraulic landing gear, leaf spring landing gear has a simpler structure, fewer parts, lighter overall weight, and is easier to maintain.

[0003] However, the materials, thickness, width, effective length, and installation position of existing leaf springs are usually determined after the design and assembly are completed, and their stress and deformation patterns are also fixed. Each time an aircraft lands, the leaf spring generally starts bending from the same initial state, and the magnitude of the initial support reaction force in the subsequent taxiing phase cannot be adjusted in advance according to the actual weight and impact of the landing.

[0004] In other words, a softer leaf spring provides better cushioning during light-load landings, but can lead to excessive bending and insufficient remaining travel under heavy loads or high descent speeds. A stiffer leaf spring, while improving support under heavy loads, is less likely to deform sufficiently during light-load landings, potentially transmitting more impact to the fuselage.

[0005] Therefore, it is necessary to design an adaptive vibration reduction structure that can mechanically adaptively adjust the working state of the leaf spring by utilizing the actual dynamic upward stroke generated in the initial stage of landing, and readjust the pre-bending degree of the leaf spring according to the quasi-static load balance state formed in the gliding stage after the main landing impact weakens, so as to take into account the support capacity and gliding vibration reduction effect under different load conditions. Summary of the Invention

[0006] The technical problem to be solved by the present invention is that the initial working state of the existing aircraft landing gear leaf springs is relatively fixed, making it difficult to passively adjust using the actual dynamic compression stroke generated during the aircraft landing process, and to form a support state that is compatible with the quasi-static load balance state in the subsequent taxiing phase. This results in the disadvantage that it is difficult to balance the airframe support capacity and vibration reduction effect. To address this, we propose an adaptive vibration reduction structure for the aircraft landing gear buffer strut.

[0007] To achieve the above objectives, this application adopts the following technical solution: an adaptive vibration reduction structure for an aircraft landing gear buffer strut, comprising a base plate and columns respectively fixedly installed on the upper ends of both sides of the base plate, with sliding plates slidably embedded on the inner sides of both columns, and a leaf spring fixedly connected to the side of each sliding plate away from the middle of the base plate, and a wheel rotatably installed on the end of each leaf spring away from the corresponding sliding plate. Each column is rotatably mounted with a winch at its top, with a rope wound around its outer side. A positioning block is fixedly mounted on the upper surface of the leaf spring near the wheel. The end of the rope away from the winch is fixedly connected to the positioning block. A spiral groove is formed on the inner wall of the winch. A top rod is fixedly mounted on the upper end of the slide plate. The winch is movably sleeved on the outside of the top rod. A protrusion is fixedly mounted on the outer wall of the top rod, and the protrusion slides into the spiral groove. The spiral groove rotates in the same direction as the winch winds the rope, so that when the slide plate moves upward, the top rod moves along the spiral groove through the protrusion and drives the winch to wind the rope. This causes the leaf spring to bend in the direction of bending when the wheel is under force, and the elastic restoring force generated by the leaf spring reacts to the top rod through the positioning block, the rope, and the winch, thus creating a reverse force to prevent the slide plate from moving upward.

[0008] Preferably, hollow cylinders are fixedly installed on both lower ends of the base plate, and driven rods are fixedly installed on the lower end of the slide plate. The driven rods penetrate downward through the base plate and extend into the hollow cylinders. The outer circumferential surface of the driven rods slides against the inner sidewall of the hollow cylinders. Multiple sets of through holes are opened along the axial direction of the driven rods. The multiple sets of through holes are distributed in a circular pattern with their axis as the center on the cross-section of the driven rods, and form the main flow channels for liquid medium on the upper and lower sides of the driven rods. The hollow cylinders are filled with liquid medium.

[0009] Preferably, a flexible cap is sealed to the lower end of the cavity cylinder, and a throttling baffle is fixedly installed inside the cavity cylinder. The throttling baffle is located between the driven rod and the flexible cap. A compensation through hole is opened through the throttling baffle. The diameter of the compensation through hole is smaller than the diameter of any through hole on the driven rod, and the flow cross-sectional area of ​​the compensation through hole is smaller than the total flow cross-sectional area of ​​multiple through holes on the driven rod. The flexible cap is connected to the inner cavity of the cavity cylinder through the compensation through hole.

[0010] Preferably, an L-plate is fixedly installed on the lower end face of the leaf spring, the L-plate is slidably sleeved on the outside of the cavity cylinder, a spring is sleeved on the outside of the cavity cylinder, the upper end of the spring is fixedly connected to the base plate, and the lower end of the spring is fixedly connected to the L-plate.

[0011] Preferably, a limiting ring is fixedly sleeved on the outer side of the cavity cylinder, and the outer diameter of the limiting ring is larger than the inner diameter of the L plate.

[0012] Preferably, the inner wall of the cavity cylinder is provided with an annular platform, and the driven rod abuts against the upper surface of the annular platform in the initial state.

[0013] Preferably, a groove is provided on the inner side of the column, and there is a certain gap between the groove and the slide plate. Multiple balls are rolled and embedded on the outer side wall of the slide plate, and the balls roll and abut against the surface of the groove.

[0014] Preferably, a lower baffle is fixedly installed at the upper end of the column, the lower baffle is rotatably sleeved on the outside of the winch, and a guide hole for the winch rope to pass through is opened through the inner side of the lower baffle.

[0015] Preferably, a comb block is fixedly installed on the upper end face of the leaf spring near the slide plate, and a guide hole for the winding rope to pass through is also opened through the inner side of the comb block.

[0016] Preferably, the base plate is detachably connected to the aircraft bottom load-bearing structure, the edge of the base plate is provided with multiple mounting holes at intervals, fasteners are inserted in the mounting holes, a buffer pad is provided between the base plate and the aircraft bottom, and reinforcing ribs are fixedly installed between the base plate and the two side columns.

[0017] The technical effects of this invention are as follows: By linking the sliding plate, push rod, protrusion, spiral groove, winch, winch rope, and leaf spring, the dynamic upward movement formed during the initial landing phase of the aircraft under the combined effects of weight, descent speed, ground reaction force, and inertia is converted into a unidirectional pre-bending of the leaf spring. This allows the leaf spring to adapt to the actual dynamic response of the landing process and form a corresponding working state. Simultaneously, the elastic restoring force generated by the pre-bending of the leaf spring can be fed back to the push rod through the positioning block, winch rope, and winch, creating a reverse force on the sliding plate as it continues to move upward. Within the elastic deformation range of the leaf spring, this feedback effect is correspondingly enhanced as the degree of pre-bending increases, thus making the support response under landing impact more gradual. After the landing impact weakens and the aircraft enters the taxiing phase, the sliding plate can gradually achieve a quasi-static equilibrium between the aircraft supporting load, the elastic action of the leaf spring and spring, and the ground supporting action, and release part of the pre-bending, allowing the leaf spring to enter the taxiing phase in a state adapted to the current load condition. The flow damping formed by the driven rod and the liquid medium in the cavity, combined with the elastic reset of the spring, buffers the rapid ascent and descent of the sliding plate and the pre-bending adjustment process. The throttling baffle placed between the driven rod and the flexible cap uses a small compensation through hole to restrict the flexible cap from rapidly absorbing or releasing liquid under instantaneous impact, reducing the weakening of the main damping flow by the rapid deformation of the flexible cap, while allowing it to complete the net volume compensation generated by the entry and exit of the driven rod during a slower volume change process, thus taking into account both the damping effect and the volume compensation requirement.

[0018] The advantages of this invention are: it can directly utilize the lifting and lowering motion generated during aircraft landing and taxiing to mechanically adjust the working state of the leaf spring, eliminating the need for additional sensors, controllers, and active drive components, resulting in a simpler overall structure; specifically, during landing, the actual dynamic compression stroke generated by the landing gear is used as the mechanical input, rather than directly equating the upward movement of the sliding plate to the actual aircraft load, ensuring that the pre-bending adjustment of the leaf spring corresponds to the actual dynamic response of the landing. Upon entering the taxiing phase, the sliding plate gradually forms an equilibrium position adapted to the quasi-static load state, retaining sufficient elastic deformation capacity of the leaf spring under lower load conditions, and providing effective support through larger pre-bending and feedback reaction forces under higher load conditions. Simultaneously, the fluid damping, spring, throttling baffle, and flexible cap work together. The throttling baffle limits the direct response of the flexible cap to rapid pressure changes, ensuring that the main damping fluid flow still primarily uses the multiple sets of through-holes on the driven rod as the main channel, while the flexible cap mainly undertakes slower net volume compensation, making the transition of the sliding plate from the landing high position to the taxiing equilibrium position smoother and improving the adaptability of the landing gear in different working phases. Attached Figure Description

[0019] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts: Figure 1 This is a top view of the overall structure of the landing gear of the present invention; Figure 2 This is a bottom view of the overall structure of the landing gear of the present invention; Figure 3 This is a partial side view of the landing gear structure of the present invention; Figure 4 This is a cross-sectional view of the structure of the base plate, column, cavity cylinder, and lower baffle plate of the present invention. Figure 5 This is a partial exploded view of the landing gear structure of the present invention; Figure 6 This is a cross-sectional view of the structure of the base plate, column, cavity cylinder, and lower baffle plate of the present invention. Figure 7 This is a cross-sectional view of the winch structure of the present invention; Figure 8 This is a top view schematic diagram of the structure of the base plate, column, and slide plate of the present invention.

[0020] Legend: 1. Base plate; 2. Column; 21. Slide groove; 3. Slide plate; 31. Top rod; 32. L-plate; 33. Spring; 34. Driven rod; 35. Ball bearing; 36. Protrusion; 4. Leaf spring; 41. Positioning block; 42. Machine wheel; 43. Combing block; 5. Winch; 51. Spiral groove; 6. Winding rope; 7. Hollow cylinder; 71. Limiting ring; 72. Flexible cap; 8. Lower stop plate. Detailed Implementation

[0021] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0022] According to one embodiment of the present invention, Figures 1 to 8 As shown.

[0023] The material, thickness, width, effective length, and installation position of the existing leaf spring 4 are usually determined after the design and assembly are completed, and its stress and deformation laws are also fixed. Each time the aircraft lands, the leaf spring 4 generally starts to bend from the same initial state. It is difficult to passively adjust the working state of the leaf spring 4 by utilizing the dynamic compression stroke formed by the aircraft weight, descent speed, ground reaction force, and airframe inertia during the actual landing process.

[0024] In other words, when leaf spring 4 is designed to be softer, it provides better cushioning during light-load landings, but under heavy loads or high descent speeds, it is prone to excessive bending and insufficient remaining travel. When leaf spring 4 is designed to be stiffer, it can improve support capacity under heavy loads, but it is not easy to deform sufficiently during light-load landings, and the impact may still be transmitted to the fuselage in greater quantities.

[0025] To address this problem, the present invention incorporates the following design in an adaptive vibration reduction structure for an aircraft landing gear buffer strut: An adaptive vibration reduction structure for an aircraft landing gear buffer strut includes a base plate 1 and columns 2 fixedly installed on the upper ends of both sides of the base plate 1. Slide plates 3 are slidably embedded on the inner side of both columns 2. Each slide plate 3 is fixedly connected to a leaf spring 4 on the side away from the middle of the base plate 1. Each leaf spring 4 is rotatably mounted with a wheel 42 on the end away from the corresponding slide plate 3. Each column 2 has a winch 5 rotatably mounted on its upper end. A rope 6 is wound around the outside of the winch 5. A positioning block 41 is fixedly mounted on the upper end face of the leaf spring 4 near the wheel 42. The end of the rope 6 away from the winch 5 is fixedly connected to the positioning block 41. A spiral groove 51 is opened on the inner side wall of the winch 5. A top rod 31 is fixedly mounted on the upper end of the slide plate 3. The winch 5 is movably sleeved on the outside of the top rod 31. A protrusion 36 is fixedly mounted on the outer side wall of the top rod 31. The protrusion 36 is slidably embedded in the spiral groove 51, and the spiral direction of the spiral groove 51 is matched with the winding direction of the winch 5 on the rope 6.

[0026] During aircraft landing, the wheels 42 first contact the ground and experience an upward impact. This force is transmitted through the wheels 42 to the leaf springs 4, causing the leaf springs 4 and the sliding plate 3, which is fixedly connected to the leaf springs 4, to move upward relative to the column 2. Since the sliding plate 3 can slide along the column 2, in the initial landing phase, a portion of the upward displacement generated by the wheels 42 is not immediately converted into bending deformation of the leaf springs 4, but rather first drives the leaf springs 4 and the sliding plate 3 to move upward as a whole. It should be noted that the upward displacement of the sliding plate 3 during the landing phase is not a direct measurement of the actual aircraft load, but rather a dynamic response formed by the combined effects of aircraft weight, descent speed, ground reaction force, airframe inertia, and the combined action of the leaf springs 4, spring 33, and fluid damping. This invention directly utilizes the actual upward displacement generated by this dynamic response as the mechanical input. As the slide plate 3 moves upward, the top rod 31 at its upper end moves upward synchronously and gradually extends into the winch 5. The protrusion 36 on the outer side of the top rod 31 moves along the spiral groove 51 and, guided by the spiral groove 51, exerts a circumferential pushing effect on the winch 5, thereby converting the linear upward movement of the top rod 31 into the rotation of the winch 5.

[0027] As the winch 5 rotates, the rope 6 wound around its outer side is gradually wound up, shortening the effective length of the rope 6 between the winch 5 and the positioning block 41. This, in turn, pulls the leaf spring 4 closer to the wheel 42 via the positioning block 41, causing the leaf spring 4 to pre-bend synchronously along the direction of subsequent bending of the wheel 42 as it moves upwards with the slide plate 3. The greater the upward distance of the slide plate 3, the greater the distance the push rod 31 enters the winch 5, and the greater the rotation angle of the winch 5 and the amount of rope 6 wound up, resulting in a larger pre-bending of the leaf spring 4. Simultaneously, the elastic restoring force generated after the pre-bending of the leaf spring 4 creates a reverse torque on the winch 5 through the positioning block 41 and the rope 6. This reverse torque is then transmitted to the push rod 31 through the cooperation of the spiral groove 51 and the protrusion 36, creating a reverse force on the continued upward movement of the slide plate 3. When the leaf spring 4 is within its elastic deformation range, this reverse force tends to increase with the increase in pre-bending, thus providing gradually enhanced feedback support to the slide plate 3 as it continues to move upwards under a large landing impact.

[0028] After the aircraft completes its main landing impact and gradually transitions into the ground taxiing phase, the dynamic impact generated at the moment of landing gradually weakens, and the speed and acceleration of the sliding plate 3 also decrease. At this time, the elastic recovery effect of the leaf spring 4 causes the sliding plate 3 to fall a certain distance from its higher position during the landing phase. The push rod 31 moves down accordingly, and through the cooperation of the protrusion 36 and the spiral groove 51, it drives the winch 5 to rotate in the opposite direction, causing the winch 5 to release part of the previously wound rope 6, thereby appropriately reducing the pre-bending amount of the leaf spring 4. As the system gradually transitions from a dynamic impact state to a quasi-static state dominated by the airframe supporting the load, the sliding plate 3 gradually reaches a relative balance between the airframe supporting load, the elastic action of the leaf spring 4 and spring 33, and the ground supporting action on the wheel 42, and stabilizes at a position adapted to the current taxiing load state, so that the leaf spring 4 maintains the corresponding pre-bending and supporting state, and enters the subsequent taxiing buffering process in this state.

[0029] In the quasi-static load state after entering the ground for taxiing, when the aircraft's supporting load is small, the required supporting force to maintain the aircraft is relatively small. The sliding plate 3 can fall down a greater distance, allowing the winch 5 to release more of the winch rope 6. The leaf spring 4 maintains a relatively small pre-bending amount, preserving sufficient elastic deformation capacity while meeting the normal support requirements of the aircraft. This allows the leaf spring 4 to generate sufficient elastic bending when the wheels 42 are subjected to runway undulations or minor impacts. Conversely, when the aircraft's supporting load is large, the sliding plate 3 will stabilize at a relatively high position, allowing the winch 5 to maintain a larger winch rope 6 winding amount. The leaf spring 4 maintains a correspondingly larger pre-bending amount and initial supporting reaction force to meet the support requirements under a larger load state. Thus, the same leaf spring 4 does not need to simply increase its own fixed stiffness to accommodate heavy load conditions. Instead, it can passively adjust according to the actual dynamic compression stroke during the landing phase and form different working starting points according to the quasi-static equilibrium position during the taxiing phase. This maximizes the elastic deformation capacity of the leaf spring 4 while meeting effective support requirements, improving the cushioning effect during taxiing.

[0030] In addition, by fixing hollow cylinders 7 to the lower ends of both sides of the base plate 1, and fixing driven rods 34 to the lower end of the slide plate 3, the driven rods 34 penetrate the base plate 1 downward and extend into the hollow cylinders 7, and the outer circumferential surface of the driven rods 34 slides against the inner wall of the hollow cylinders 7, so that the driven rods 34 can move synchronously inside the hollow cylinders 7 as the slide plate 3 rises and falls; the hollow cylinders 7 are filled with liquid medium, and the driven rods 34 have multiple sets of through holes through them along the axial direction. The multiple sets of through holes are distributed in a circular interval with their axis as the center on the cross-section of the driven rods 34, so that the liquid medium on the upper and lower sides of the driven rods 34 mainly exchanges and flows through each through hole during its rise and fall.

[0031] When the aircraft lands, the wheels 42 are subjected to a large instantaneous impact, which causes the leaf spring 4 and the slide plate 3 to move rapidly upward. The driven rod 34 then moves upward along the cavity cylinder 7. The liquid medium is restricted by the cross-section of the through holes during the process of passing through each through hole, forming a flow resistance, and generating a damping effect on the driven rod 34 in the opposite direction of its movement. The faster the slide plate 3 moves upward, the greater the amount of liquid medium that needs to pass through the through holes per unit time, and the more obvious the damping effect is. This can mitigate the rapid upward movement of the slide plate 3 at the moment of landing, and make the process of the top rod 31 driving the winch 5 to rotate and the winch rope 6 pulling the leaf spring 4 to form a pre-bend smoother.

[0032] After the main landing impact subsides, the elastic recovery of the leaf spring 4 causes the slide plate 3 to fall downwards, and the driven rod 34 will also move downwards along the cavity cylinder 7 simultaneously. At this time, the liquid medium flows in the opposite direction through the through holes again, and continues to dampen the descent of the driven rod 34, so that the slide plate 3 will not fall back quickly when transitioning from the higher position of the landing phase to the equilibrium position of the taxiing phase. After entering the ground taxiing phase, when the wheels 42 are affected by the runway undulations and the slide plate 3 experiences a small range of rise and fall, the driven rod 34 will still push the liquid medium back and forth through the through holes, using the liquid flow resistance to consume some of the vibration energy, thereby taking into account the impact mitigation during the landing phase, the rebound suppression after landing, and the small vibration attenuation during the taxiing phase.

[0033] Furthermore, a flexible cap 72 is sealed to the lower end of the cavity cylinder 7, and a throttling baffle is fixedly installed inside the cavity cylinder 7, located between the driven rod 34 and the flexible cap 72. A compensation through-hole is formed through the throttling baffle. The diameter of the compensation through-hole is smaller than the diameter of the through-hole on the driven rod 34, and the flow cross-sectional area of ​​the compensation through-hole is smaller than the total flow cross-sectional area of ​​the multiple through-holes on the driven rod 34. The flexible cap 72 is connected to the inner cavity of the cavity cylinder 7 through the compensation through-hole. Thus, the throttling baffle separates the flexible cap 72 from the main liquid working area where the driven rod 34 is located, allowing the flexible cap 72 to still perform volume compensation, but the liquid exchange rate between it and the inner cavity of the cavity cylinder 7 is limited by the compensation through-hole.

[0034] When the aircraft lands and the driven rod 34 moves rapidly, the exchange volume of liquid medium on the upper and lower sides of the driven rod 34 is relatively large. It mainly flows through multiple sets of through holes on the driven rod 34 and forms damping. Since the flow cross section of the compensation through hole is relatively small, the liquid medium in the cavity cylinder 7 is difficult to enter or exit the compensation space where the flexible cap 72 is located in a large amount at an instant. This limits the rapid and large expansion or contraction of the flexible cap 72 with instantaneous pressure changes, reduces the situation where the flexible cap 72 absorbs pressure changes through its own rapid deformation and weakens the flow resistance on both sides of the driven rod 34, so that the multiple sets of through holes on the driven rod 34 can continue to serve as the main liquid exchange channel during rapid dynamic processes.

[0035] Because the liquid medium itself has low compressibility, the length of the driven rod 34 extending into the cavity 7 changes as it moves up and down, causing a corresponding change in the volume occupied by the driven rod 34 within the cavity 7. When the driven rod 34 moves at a relatively low speed, or after the main landing impact has subsided, the liquid medium can gradually enter or exit the compensation space where the flexible cap 72 is located through the compensation through-hole, causing the flexible cap 72 to slowly expand or contract to compensate for the net volume difference caused by the driven rod 34 entering and exiting the cavity 7. Specifically, when the length of the driven rod 34 extending downward into the cavity 7 increases, some of the liquid medium it displaces gradually enters the space where the flexible cap 72 is located through the compensation through-hole, causing the flexible cap 72 to expand outward; when the driven rod 34 exits upward and the volume it occupies within the cavity 7 decreases, the flexible cap 72 gradually contracts, allowing the liquid medium to replenish the cavity 7 through the compensation through-hole. Thus, different flow capacities are formed by the through hole on the driven rod 34 and the compensation through hole on the throttling baffle. The former mainly undertakes the liquid exchange and damping effect during rapid movement, while the latter mainly controls the volume compensation speed of the flexible cap 72. This ensures the liquid damping effect while also taking into account the volume compensation requirements inside the cavity cylinder 7.

[0036] Secondly, by fixing the L-plate 32 to the lower end face of the leaf spring 4 and sliding the L-plate 32 onto the outside of the cavity cylinder 7, the cavity cylinder 7 can guide the lifting and lowering movement of the L-plate 32. When the aircraft lands and the leaf spring 4 and the sliding plate 3 move upward as a whole, the L-plate 32 will move upward synchronously with the leaf spring 4 and slide along the outside of the cavity cylinder 7, thereby making the movement direction of the leaf spring 4 closer to the sliding plate 3 more stable and reducing the possibility of lateral deviation or swaying after landing impact.

[0037] Meanwhile, a spring 33 is fitted on the outer side of the cavity cylinder 7. The upper end of the spring 33 is fixedly connected to the base plate 1, and the lower end is fixedly connected to the L-plate 32. When the L-plate 32 moves upward with the leaf spring 4 and gradually approaches the base plate 1, the spring 33 is compressed and stores elastic potential energy, while simultaneously exerting a downward elastic force on the L-plate 32. In this way, during the upward movement of the sliding plate 3 and the leaf spring 4, in addition to being subject to the flow resistance formed by the liquid medium inside the cavity cylinder 7, it is also necessary to overcome the gradually increasing elastic force of the spring 33, so that the upward movement of the sliding plate 3 during landing is not too sudden, and the spring 33 can further absorb some of the landing impact.

[0038] As the primary landing impact gradually subsides, the compressed spring 33 pushes the L-plate 32 downwards to reset, and through the leaf spring 4, it drives the sliding plate 3 to gradually descend from its higher position during landing to its equilibrium position during gliding. During this process, the driven rod 34 moves downwards along the cavity cylinder 7 simultaneously. The liquid medium inside the cavity cylinder 7 generates damping through the through-holes, thus limiting the rapid release of the spring 33. Therefore, by utilizing the spring 33 to provide elastic reset and auxiliary buffering, while the liquid medium inside the cavity cylinder 7 dampens the lifting process, the two work together to reduce the rapid rebound or repeated up-and-down jerking of the sliding plate 3 after landing, making its transition from the landing impact state to the gliding equilibrium state smoother.

[0039] Upon entering the ground taxiing phase, when the wheels 42 experience minor vibrations due to runway undulations, the L-plate 32 moves slightly up and down outside the cavity cylinder 7 along with the leaf spring 4. The spring 33 then repeatedly compresses and recovers, further buffering the vibrations generated during taxiing in conjunction with the elastic deformation of the leaf spring 4 and the damping effect of the liquid medium within the cavity cylinder 7. This provides a stable return tendency for the skid plate 3 while avoiding significant rebound due to relying solely on the elastic recovery of the leaf spring 4, ensuring the entire buffer structure maintains a relatively stable working state during both landing and taxiing phases.

[0040] A limiting ring 71 is fixedly sleeved on the outer side of the cavity cylinder 7, and the outer diameter of the limiting ring 71 is larger than the inner diameter of the L plate 32. This allows the L plate 32 to be limited when it moves downward along the outer side of the cavity cylinder 7 to the limiting ring 71, preventing the L plate 32 from continuing to move downward and detaching from the cavity cylinder 7. It also limits the lowest position of the leaf spring 4 and the sliding plate 3.

[0041] The inner wall of the cavity cylinder 7 is provided with an annular platform. The driven rod 34 abuts against the upper end face of the annular platform in the initial state. The annular platform provides bottom support and position limitation for the driven rod 34, so that the slide plate 3, leaf spring 4 and driven rod 34 can be kept in a relatively stable initial position when the aircraft is not subjected to landing impact. Together with the limit ring 71, it limits the initial assembly position and range of motion of the entire lifting mechanism, preventing the moving parts from continuing to move downward in the unloaded state.

[0042] A groove 21 is provided on the inner side of the column 2, and a certain clearance is reserved between the groove 21 and the slide plate 3. Multiple balls 35 are rolled and embedded on the outer wall of the slide plate 3, and the balls 35 roll and abut against the surface of the groove 21. When the slide plate 3 moves up and down along the column 2, it mainly forms rolling contact between the balls 35 and the groove 21, thereby reducing the frictional resistance generated by the direct sliding between the slide plate 3 and the column 2. This allows the slide plate 3 to move up and down more smoothly after being subjected to the landing impact transmitted by the wheel 42. In addition, the multiple balls 35 distributed on the outer side of the slide plate 3 can also provide auxiliary support and guidance for the slide plate 3, so that the slide plate 3 maintains a relatively stable lifting trajectory during the landing impact and subsequent sliding vibration, thereby ensuring that the push rod 31, driven rod 34 and winch 5 and other related moving parts can work normally.

[0043] A lower baffle 8 is fixedly installed on the upper end of the column 2. The lower baffle 8 is rotatably sleeved on the outside of the winch 5, and a guide hole is opened through the inner side of the lower baffle 8 for the winch rope 6 to pass through. The lower baffle 8 can support and restrict the installation position of the winch 5, so that the winch 5 can maintain a relatively stable rotation state after being pushed by the top rod 31 and the protrusion 36. At the same time, the guide hole constrains the lead-out direction of the winch rope 6, reducing the possibility of the winch rope 6 deviating, skipping, or interfering with other structures during the rotation, winding, or release of the winch 5. A combing block 43 is fixedly installed on the upper end face of the leaf spring 4 near the slide plate 3. The inner side of the combing block 43 is also provided with a guide hole for the winding rope 6 to pass through, so that the winding rope 6 can be further combed and guided during the extension of the winding rope 6 from the winch 5 to the positioning block 41, thereby keeping the traction direction of the winding rope 6 relatively stable, avoiding large swings or local wear of the winding rope 6 during the lifting and bending process of the leaf spring 4, and enabling the winding action of the winch 5 to be transmitted to the positioning block 41 more stably, ensuring the continuity and reliability of the pre-bending adjustment process of the leaf spring 4.

[0044] Furthermore, the base plate 1 is detachably connected to the aircraft's bottom load-bearing structure. Multiple mounting holes are spaced along the edge of the base plate 1, and fasteners inserted into these holes securely fix the base plate 1 to the aircraft's bottom, facilitating the later disassembly, maintenance, and replacement of the landing gear buffer structure. A buffer pad is installed between the base plate 1 and the aircraft bottom. This buffer pad further cushions the impact and vibration generated by the wheels 42 during landing and taxiing, which are transmitted to the base plate 1 via the leaf spring 4, sliding plate 3, and uprights 2, reducing the direct transmission of high-frequency vibrations to the load-bearing structure. Simultaneously, reinforcing ribs are fixedly installed between the base plate 1 and the two uprights 2. These ribs enhance the connection strength and bending resistance between the base of the uprights 2 and the base plate 1, ensuring the uprights 2 maintain a relatively stable installation state when bearing the vertical load transmitted by the sliding plate 3 and the impact generated during landing, reducing the possibility of tilting or localized deformation at the base of the uprights 2.

[0045] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. An adaptive vibration reduction structure for an aircraft landing gear buffer strut, characterized in that: It includes a base plate and columns fixedly installed on the upper ends of both sides of the base plate. Slide plates are slidably embedded on the inner side of both columns. Each slide plate is fixedly connected to a leaf spring on the side away from the middle of the base plate. Each leaf spring is rotatably mounted with a wheel on the end away from the corresponding slide plate. Each of the columns is rotatably mounted on its upper end with a winch. A rope is wound around the outer side of the winch. A positioning block is fixedly mounted on the upper surface of the leaf spring near the wheel. The end of the rope away from the winch is fixedly connected to the positioning block. A spiral groove is formed on the inner side wall of the winch. A top rod is fixedly mounted on the upper end of the slide plate. The winch is movably sleeved on the outside of the top rod. A protrusion is fixedly mounted on the outer side wall of the top rod. The protrusion is slidably embedded in the spiral groove. The rotation direction of the spiral groove matches the winding direction of the winch. When the slide plate moves upward, the top rod drives the winch to wind the rope along the spiral groove through the protrusion, thereby pulling the leaf spring to form a pre-bend along the bending direction of the wheel. The elastic restoring force of the leaf spring is fed back to the top rod through the rope, winch, and spiral groove, forming a reverse force on the continued upward movement of the slide plate.

2. The adaptive vibration reduction structure of the aircraft landing gear buffer strut according to claim 1, characterized in that: Hollow cylinders are fixedly installed on both lower ends of the base plate. A driven rod is fixedly installed on the lower end of the slide plate. The driven rod penetrates the base plate downward and extends into the hollow cylinder. The outer circumferential surface of the driven rod slides against the inner wall of the hollow cylinder. Multiple sets of through holes are opened through the driven rod along the axial direction. The multiple sets of through holes are distributed circumferentially at intervals around the axis on the cross-section of the driven rod, and form the main flow channels for liquid medium on the upper and lower sides of the driven rod. The hollow cylinder is filled with medium.

3. The adaptive vibration reduction structure of the aircraft landing gear buffer strut according to claim 2, characterized in that: The lower end of the cavity cylinder is sealed with a flexible cap. A throttling baffle is fixedly installed inside the cavity cylinder. The throttling baffle is located between the driven rod and the flexible cap. A compensation through hole is opened through the throttling baffle. The diameter of the compensation through hole is smaller than the diameter of any of the through holes on the driven rod. The flow cross-sectional area of ​​the compensation through hole is smaller than the total flow cross-sectional area of ​​the multiple sets of through holes. The flexible cap is connected to the inner cavity of the cavity cylinder through the compensation through hole.

4. The adaptive vibration reduction structure of the aircraft landing gear buffer strut according to claim 3, characterized in that: An L-plate is fixedly installed on the lower end face of the leaf spring. The L-plate is slidably sleeved on the outside of the cavity cylinder. A spring is sleeved on the outside of the cavity cylinder. The upper end of the spring is fixedly connected to the base plate, and the lower end of the spring is fixedly connected to the L-plate.

5. The adaptive vibration reduction structure of the aircraft landing gear buffer strut according to claim 4, characterized in that: A limiting ring is fixedly sleeved on the outer side of the cavity cylinder, and the outer diameter of the limiting ring is larger than the inner diameter of the L plate.

6. The adaptive vibration reduction structure of the aircraft landing gear buffer strut according to claim 5, characterized in that: The inner wall of the cavity cylinder is provided with an annular platform, and the driven rod abuts against the upper surface of the annular platform in the initial state.

7. The adaptive vibration reduction structure for the aircraft landing gear buffer strut according to claim 1, characterized in that: The inner side of the column is provided with a sliding groove, and there is a certain gap between the sliding groove and the sliding plate. Multiple balls are rolled and embedded in the outer side wall of the sliding plate, and the balls roll and abut against the surface of the sliding groove.

8. The adaptive vibration reduction structure for the aircraft landing gear buffer strut according to claim 1, characterized in that: A lower baffle is fixedly installed at the upper end of the column. The lower baffle is rotatably sleeved on the outside of the winch. A guide hole for the winch rope to pass through is opened through the inner side of the lower baffle.

9. The adaptive vibration reduction structure of the aircraft landing gear buffer strut according to claim 8, characterized in that: A combing block is fixedly installed on the upper surface of the leaf spring near the slide plate, and a guide hole for the winding rope to pass through is also opened through the inner side of the combing block.

10. The adaptive vibration reduction structure of the aircraft landing gear buffer strut according to claim 1, characterized in that: The base plate is detachably connected to the aircraft's bottom load-bearing structure, with a buffer pad layer between them. Reinforcing ribs are fixedly installed between the base plate and the columns on both sides.

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