Landing gear anti-sway device with nonlinear inertial container

Abstract

This invention provides a landing gear anti-sway device with a nonlinear inertial container, comprising an upper end cover and a lower end cover fixedly connected. A piston rod is inserted into the lower end cover, and the lower end cover is fixedly connected to the upper torsion arm of the landing gear. The portion of the piston rod extending out of the lower end cover is fixedly connected to the lower torsion arm of the landing gear. The piston rod has two stages of pistons. The first stage piston is the piston of the hydraulic inertial container, and the inertial mass coefficient of the inertial container changes with the piston displacement, thus playing the role of energy absorption by the nonlinear inertial container. The second stage piston is the piston of the conventional hydraulic damper, which plays the role of energy absorption and energy dissipation.

Description

Technical Field

[0001] This invention relates to the field of landing gear sway technology, specifically a landing gear sway reduction device with a nonlinear inertial container. Background Technology

[0002] During ground taxiing, aircraft often experience landing gear shimmy. Landing gear shimmy is a self-excited vibration caused by the coupling of lateral and torsional motions of the landing gear struts. It has a significant negative impact on the aircraft's handling and stability during ground taxiing, seriously endangering the aircraft's safety.

[0003] Currently, the main mechanical vibration isolation element used to suppress landing gear shimmy is the damper, a traditional vibration isolation element. However, in 2002, Professor Smith of the University of Cambridge proposed a new type of vibration isolation element—the inertial container—and applied it to automotive suspension, achieving excellent vibration reduction performance. An inertial container is a device with two independent free ends, where the force at each end is proportional to the relative acceleration between the two ends. The emergence of the inertial container broke through the traditional vibration reduction method, forming a new passive control system of "inertial capacity-spring-damping," which has been proven to significantly improve the vibration reduction performance of structures.

[0004] Commonly used inertial navigation systems are mainly divided into two types: mechanical and fluid. Mechanical inertial navigation systems have a relatively complex structure and poor durability and load-bearing capacity. In comparison, fluid inertial navigation systems, especially hydraulic inertial navigation systems, have no structural gaps, experience less wear, have a long service life, a simple structure, and a small size, making them more widely applicable.

[0005] In the face of increasingly complex mechanical vibration conditions and cutting-edge research trends, nonlinear problems have gradually gained attention. Nonlinear inertial containers are better able to adapt to complex vibration conditions compared to traditional linear inertial containers. Summary of the Invention

[0006] To address the problems of the prior art, this invention provides a landing gear anti-sway device with a nonlinear inertial container. Compared with traditional damper-type anti-sway devices, it can withstand greater loads and effectively suppress landing gear swaying.

[0007] The present invention includes a sway reduction device disposed between two torsion arms of the landing gear, the sway reduction device comprising a hydraulic inertial container and an oil damper disposed on the same piston rod.

[0008] The aforementioned anti-sway device includes an upper end cover and a lower end cover fixedly connected. A piston rod is inserted into the lower end cover, and the lower end cover is fixedly connected to the upper torsion arm of the landing gear. The portion of the piston rod extending out of the lower end cover is fixedly connected to the lower torsion arm of the landing gear. The piston rod has two stages of pistons. The first-stage piston and the second-stage piston divide the cavity formed between the upper end cover and the lower end cover into three chambers. The first-stage piston is the piston of the hydraulic inertia container, which plays the role of energy absorption by the inertia container. The second-stage piston is the piston of the conventional hydraulic damper, which plays the role of energy absorption and energy dissipation.

[0009] In a further improvement, the surface of the first-stage piston that contacts the upper end cap has a spiral groove, and the spiral groove is evenly and symmetrically distributed along the axis of the first-stage piston.

[0010] In a further improvement, the inner diameter of the upper end cover is smaller than that of the lower end cover, while the outer diameter of the first-stage piston is the same as that of the upper end cover. The length of the spiral pipe formed by the first-stage piston and the upper end cover changes with the piston displacement, and the inertial mass coefficient of the inertial container also changes accordingly.

[0011] In a further improvement, the upper and lower end caps of the second-stage piston are sealed by a sealing ring. The second-stage piston has several damping holes distributed on it to achieve the energy dissipation function of the hydraulic damper. The damping holes on the second-stage piston are arranged in a circular array on the piston surface within the annular region formed by the outer diameter of the piston rod and the outer diameter of the piston.

[0012] The hydraulic piston mechanism consists of two-stage pistons and piston rods. The two-stage pistons are connected in series and are located on the same piston rod. The first-stage piston is longer than the second-stage piston in order to meet the structural requirements of the slender tube in the hydraulic inertial container.

[0013] The beneficial effects of this invention are as follows:

[0014] 1. The landing gear anti-sway device with inertia container can effectively absorb energy and reduce vibration, and the structural space occupancy is small while maintaining the original mechanical properties of the inertia container;

[0015] 2. Compared to traditional mechanical inertial containers, it has a simple structure, high durability, and can withstand the high loads present in landing gear shimmy.

[0016] 3. Nonlinear inertial containers with variable mass coefficients are better able to adapt to complex vibration conditions compared to traditional inertial containers with constant mass coefficients;

[0017] 4. By adding an inertial container working device to the traditional damper working device, the mechanical characteristics of the inertial container are fully utilized, high-frequency vibration is better suppressed, and the energy dissipation effect of the damper is increased.

[0018] 5. The working parts of the inertial container and the working parts of the oil damper are located on the same piston rod, which results in a relatively simple structure and lower processing and maintenance costs. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram illustrating the principle of the present invention;

[0021] Figure 2 This is a schematic diagram of the installation position of the landing gear anti-sway device in this invention;

[0022] Figure 3 This is a schematic diagram of the sway reduction device for the inertial container in this invention;

[0023] Figure 4 This is a partial cross-sectional schematic diagram of the sway reduction device for the inertial container in this invention.

[0024] In the diagram, 1 - upper torque arm, 2 - lower torque arm, 3 - anti-sway device, 4 - upper end cover, 5 - first stage piston, 6 - second stage piston, 7 - lower end cover, and 8 - piston rod. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] like Figure 1 As shown, this invention discloses a landing gear anti-sway device with a nonlinear inertial container. The part that realizes the vibration reduction function is a hydraulic inertial container and an oil damper, which are connected in series to form an "inertial capacity-damping" passive vibration reduction and isolation system.

[0027] like Figure 2 As shown, the vibration damping device is installed at the connection between the upper and lower torque arms of the landing gear. The lower end cover 7 is connected to the upper torque arm 1, and the piston rod 8 is connected to the lower torque arm 2.

[0028] Figure 3 The landing gear anti-sway device of the present invention is shown, including a hydraulic inertial container working part, an oil damping working part, an outer cylinder, and a hydraulic piston mechanism.

[0029] like Figure 4 As shown, the inner diameter of the upper end cover 4 is smaller than the inner diameter of the lower end cover 7, while the outer diameter of the first-stage piston 5 is the same as the inner diameter of the upper end cover 4. The length of the spiral pipe formed between the first-stage piston 5 and the upper end cover 4 changes with the piston displacement.

[0030] The hydraulic inertial container is a device that generates inertia by utilizing the flow of a liquid of a certain mass in a slender tube. Depending on the arrangement of the helical tube, hydraulic inertial containers can be divided into two types: external helical tube type and internal helical tube type. Based on the structural characteristics of the anti-sway device 3 and the motion of the landing gear's swaying motion, this invention adopts an internal helical tube structure for the hydraulic inertial container.

[0031] This invention forms a slender pipe between the first-stage piston 5 and the upper end cover 4 by opening a spiral groove on the first-stage piston 5. When the anti-sway device is working, the liquid flows in the slender pipe between the left and right chambers of the first-stage piston 5. The flow of liquid in the slender pipe realizes the encapsulation of the liquid flow inertia, thereby completing the energy absorption function of the inertia container.

[0032] The length of the spiral slender tube is constantly changing. Due to the difference between the inner diameter of the upper end cover 4 and the inner diameter of the lower end cover 7, the length of the pipe formed between the first-stage piston 5 and the upper end cover 4 changes with the movement of the piston, thereby changing the inertial mass coefficient of the inertial container in terms of structure and realizing the function of the nonlinear inertial container.

[0033] The working part of the oil damper is located on the second-stage piston 6. The second-stage piston 6 has four damping holes distributed in a circular array. In order to ensure the normal operation of the damper, the oil can flow smoothly through the damping holes between the left and right chambers of the first-stage piston 6. The second-stage piston 6 is sealed with the outer shell of the anti-sway device by a sealing ring, so as to ensure that the oil damper can play a maximum role in absorbing and dissipating energy.

[0034] The inertial force generated by the aforementioned hydraulic inertial device is mainly related to the acceleration of motion, while the damping force generated by the hydraulic damper is mainly related to the speed of motion. This invention combines the two to form an "inertial-damping" system, which plays a role in suppressing landing gear shimmy.

[0035] The sway reduction device 3 consists of an upper end cover 4, a first-stage piston 5, a second-stage piston 6, a lower end cover 7, and a piston rod 8. The upper end cover 4 and the lower end cover 7 are connected by bolts, and the lower end cover 7 is connected to the upper torque arm 1. The first-stage piston 5 and the second-stage piston 6 are fixed to the piston rod 8 from left to right, and the piston rod 8 is fixed to the lower torque arm 2. Except for the upper and lower torque arms, all the above components are distributed on the same axis and do not interfere with each other's movement, ensuring the normal operation of the sway reduction device 3.

[0036] The first-stage piston 5 and the second-stage piston 6 divide the cavity between the upper end cover 4 and the lower end cover 7 into three chambers. When the landing gear shivers, relative motion occurs between the upper torque arm 1 and the lower torque arm 2. The lower end cover 7 and piston rod 8 of the anti-shiver device 3 move with the upper and lower torque arms, respectively. The liquid flows from the leftmost chamber through the slender spiral pipe of the first-stage piston 5 into the middle chamber, and then through the damping hole on the second-stage piston 6 into the rightmost chamber. At the same time, with the reciprocating vibration of the landing gear, the length of the slender spiral pipe changes continuously, and the liquid flows back and forth accordingly. The inertial mass coefficient of the nonlinear inertial container also changes continuously. The anti-shiver device 3 absorbs and dissipates energy through the flow of liquid, thus achieving the function of suppressing shiver.

[0037] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. In particular, for the device embodiments, the above descriptions are merely preferred embodiments of the present invention. Since they are fundamentally similar to the method embodiments, the descriptions are relatively simple, and relevant parts can be referred to the descriptions of the method embodiments. The above descriptions are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention, without departing from the principle of the present invention, should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A landing gear anti-sway device with a nonlinear inertial container, characterized in that: The device includes a sway reduction mechanism located between the two torsion arms of the landing gear. The sway reduction mechanism includes a hydraulic inertial container and an oil damper mounted on the same piston rod. The hydraulic inertial container adopts an internal spiral tube structure. The sway reduction mechanism includes an upper end cover (4) and a lower end cover (7) fixedly connected. A piston rod is inserted into the lower end cover (7). The lower end cover (7) is fixedly connected to the upper torsion arm (1) of the landing gear. The part of the piston rod (8) extending out of the lower end cover (7) is fixedly connected to the lower torsion arm (2) of the landing gear. The piston rod (8) has two stages of pistons. The first stage piston (5) is the piston where the hydraulic inertial container is located, and the second stage piston (6) is the piston where the conventional oil damper is located. The first stage piston (5) and the second stage piston (6) divide the cavity formed between the upper end cover (4) and the lower end cover (7) into three chambers. The first stage piston... (5) The surface in contact with the upper end cover (4) has a spiral groove. The spiral groove is evenly and symmetrically distributed along the axis relative to the first stage piston (5). When the landing gear oscillates, the upper torsion arm (1) and the lower torsion arm (2) of the landing gear move relative to each other. The lower end cover (7) and piston rod (8) of the anti-sway device (3) move with the upper and lower torsion arms respectively. The liquid flows from the leftmost chamber through the slender spiral pipe of the first stage piston (5) into the middle chamber, and then through the damping hole on the second stage piston (6) into the rightmost chamber. At the same time, with the reciprocating vibration of the landing gear, the length of the slender spiral pipe also changes continuously. The liquid flows back and forth, and the inertial mass coefficient of the nonlinear inertial container also changes continuously. The anti-sway device (3) realizes the energy absorption and energy dissipation effect through the flow of liquid, and realizes the function of the anti-sway device to suppress oscillation.

2. The landing gear anti-sway device with nonlinear inertial container according to claim 1, characterized in that: The inner diameter of the upper end cover (4) is smaller than that of the lower end cover (7), the outer diameter of the first-stage piston (5) is the same as that of the upper end cover (4), and the outer diameter of the second-stage piston (6) is the same as that of the lower end cover (7).

3. The landing gear anti-sway device with nonlinear inertial container according to claim 1, characterized in that: The upper and lower end caps (7) of the second-stage piston (6) are sealed by a sealing ring, and the second-stage piston (6) has a number of damping holes.

4. The landing gear anti-sway device with nonlinear inertial container according to claim 3, characterized in that: The damping holes on the second-stage piston (6) are arranged in a circular array on the piston surface within the annular region formed by the outer diameter of the piston rod and the outer diameter of the piston.

5. The landing gear anti-sway device with nonlinear inertia container according to claim 1, characterized in that: The first-stage piston (5) is longer than the second-stage piston (6).

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