Self-unfolding multi-stage telescopic variable damping mechanism

Abstract

A self-unfolding multi-stage telescopic variable damping mechanism relates to the field of carrier rocket reuse and comprises a large-end support lug, a damping rod, a damping cylinder, an outer cylinder, a first-stage damping assembly, a second-stage damping assembly, a small-end support lug and an oil tank, the large-end support lug is provided with an inner cavity, one end of the outer cylinder is connected with the large-end support lug, and the inner part of the outer cylinder is communicated with the inner cavity of the large-end support lug; the damping cylinder is slidably connected into the outer cylinder, the second-stage damping assembly is connected to the end, close to the large-end supporting lug, of the outer wall face of the damping cylinder, the damping rod is slidably connected into the damping cylinder, the second-stage damping assembly is connected to the end, close to the large-end supporting lug, of the damping rod, and the end, away from the large-end supporting lug, of the damping rod is connected with the small-end supporting lug. Sealing assemblies are arranged between the end, away from the large-end supporting lug, of the outer cylinder and the damping cylinder and between the end, away from the large-end supporting lug, of the damping cylinder and the damping rod. And the oil tank is communicated with the inner cavity of the large-end support lug. The method is suitable for wide-area landing buffer conditions of medium and large carrier rockets and meets the requirement for higher buffer performance.

Description

Technical Field

[0001] The present application belongs to the technical field of launch vehicle reuse, and specifically relates to a damping mechanism for buffering a landing mechanism of a launch vehicle. Background Art

[0002] As the key landing mechanism for the vertical recovery of launch vehicles, its buffer structure and performance will directly affect the success or failure of the vertical recovery mission. At present, the vertical recovery of launch vehicles generally adopts the recovery scheme of the folding leg landing buffer mechanism. Most of its buffer structure design schemes adopt metal crushing type such as aluminum honeycomb, and the buffer structure is integrated and designed inside the last section of the multi-section landing mechanism. This buffer structure cannot be reused; some landing mechanisms use hydraulic buffer mechanisms, which are also integrated inside the last section of the multi-section landing mechanism or used alone as a supporting auxiliary rod. Their size is small and does not have the dual-stage variable damping buffering capacity. Summary of the invention

[0003] The technical problem solved by the present application is: to overcome the deficiencies of the prior art and to provide a large-size, bidirectionally variable-damping, unidirectionally pressure-limited, multi-stage telescopic variable-damping mechanism for launch vehicle network recovery, which can solve the problems of wide-range landing cushioning conditions for medium and large launch vehicles, refined design of multi-stage cushioning performance, and unidirectional pressure limiting to improve cushioning performance.

[0004] The technical solutions provided by this application are as follows:

[0005] A self-expanding multi-stage telescopic variable damping mechanism comprises a large end support ear, a damping rod, a damping cylinder, an outer cylinder, a primary damping assembly, a secondary damping assembly, a small end support ear and an oil tank, wherein the large end support ear is provided with an internal cavity, one end of the outer cylinder is connected to the large end support ear, the interior of the outer cylinder is communicated with the internal cavity of the large end support ear, the damping cylinder is slidably connected to the interior of the outer cylinder, the secondary damping assembly is connected to one end of the outer wall surface of the damping cylinder close to the large end support ear, the damping rod is slidably connected in the damping cylinder, the secondary damping assembly is connected to one end of the damping rod close to the large end support ear, the end of the damping rod away from the large end support ear is connected to the small end support ear, sealing assemblies are arranged between the end of the outer cylinder away from the large end support ear and the damping cylinder, and between one end of the damping cylinder away from the large end support ear and the damping rod; the oil tank is communicated with the internal cavity of the large end support ear; at least one of the small end support ear and the large end support ear is connected to a component requiring buffering.

[0006] A spring seat and a first spring are arranged in the internal cavity of the large end support ear, the left end of the spring seat is opposite to the end of the damping cylinder, one end of the first spring contacts the inside of the spring seat, and the other end contacts the inner wall surface of the internal cavity of the large end support ear away from the small end support ear.

[0007] The primary damping assembly includes a primary screw plug and a plurality of primary damping holes arranged on the primary screw plug. The primary screw plug is threadedly fixed to the end of the damping rod close to the large end support ear. The primary screw plug is cylindrical, the outer diameter of the primary screw plug matches the damping cylinder, and the primary damping hole connects the two sides of the primary screw plug along its own axial direction.

[0008] The secondary damping assembly includes a secondary screw plug and a plurality of secondary damping holes opened on the secondary screw plug. The secondary screw plug is threadedly connected to the end of the outer wall of the damping cylinder near the large end support ear. The outer diameter of the secondary screw plug matches the inner wall of the outer cylinder. The secondary damping hole connects the two sides of the secondary screw plug along its own axis.

[0009] The oil tank is connected to the large-end lug through the oil tank base, and a one-way pressure limiting component is connected to the outlet of the oil tank to play a damping role in the process of oil in the internal cavity of the large-end lug flowing into the oil tank; an oil tank piston is arranged in the oil tank, and the space between the oil tank piston and the one-way pressure limiting component is a storage space for oil; when the oil in the oil tank flows into the internal cavity of the large-end lug through the one-way pressure limiting component, the oil tank piston moves in the direction approaching the one-way pressure limiting component in the oil tank, and vice versa, moves in the direction away from the one-way pressure limiting component.

[0010] The one-way pressure-limiting assembly includes a spring sleeve, a pressure-limiting spring, a pressure-limiting piece, a steel ball and a pressure-limiting piston. The oil tank base is provided with a transverse connecting through hole and a longitudinal connecting through hole. The transverse connecting through hole is parallel to the length direction of the oil tank, and one end is connected to the inner cavity of the oil tank, and the other end is connected to the inner cavity of the large-end support ear through the longitudinal connecting through hole. The end of the transverse connecting through hole away from the longitudinal connecting through hole is a connecting hole, and the diameter of the connecting hole is larger than the diameter of the transverse connecting through hole. The outlet of the oil tank is installed in the connecting hole, and the spring sleeve is installed at the outlet of the oil tank. The pressure-limiting piston is fixedly connected to the transverse connecting through hole in the mouth, the pressure-limiting part is located in the connecting hole and between the outlet of the oil tank and the pressure-limiting piston, the pressure-limiting spring is located in the spring sleeve and is used to push the pressure-limiting part, the steel ball is located in the pressure-limiting piston, and the space between the steel ball and the pressure-limiting piston is used for oil to pass through. The diameter of the steel ball is larger than the inner diameter of the pressure-limiting part facing one end of the steel ball. The pressure-limiting part is provided with a pressure-limiting damping hole, so that after the steel ball blocks the end of the pressure-limiting part, the oil can enter the spring sleeve through the pressure-limiting damping hole, and the end of the spring sleeve away from the pressure-limiting part is a through hole.

[0011] The inner wall surface of the pressure-limiting piston is provided with a plurality of flow grooves along the circumferential direction.

[0012] The end of the inner wall surface of the pressure-limiting piston away from the first flange is connected to the limiting portion, and the steel ball is located on the side of the limiting portion facing the pressure-limiting member.

[0013] The pressure limiting part is a cylindrical structure, which is inserted into the pressure limiting piston and is slidingly connected to the pressure limiting piston along the axial direction of the pressure limiting piston. A plurality of pressure relief grooves are circumferentially arranged on the outer wall surface of the pressure limiting part, and the pressure relief grooves are distributed along the radial direction of the pressure limiting part. The pressure limiting damping hole penetrates from the inner wall surface of the pressure limiting part to the outer wall surface, and one end of the pressure limiting damping hole is connected to the pressure relief groove.

[0014] A first flange is arranged on the outside of the end of the pressure-limiting piston away from the longitudinal connecting through hole, a step surface is formed between the connecting hole and the transverse connecting through hole, and the end of the first flange is in contact with the step surface; a second flange is connected to the end of the pressure-limiting member away from the steel ball, the second flange is located on the side of the first flange away from the steel ball, and the outer diameter of the second flange is smaller than the inner diameter of the connecting hole.

[0015] In summary, this application at least includes the following beneficial technical effects:

[0016] (1) It is applicable to the wide-range landing cushion conditions of medium and large launch vehicles, and can be used for landing conditions such as large attitude deviation and large landing speed.

[0017] (2) The multi-level buffering performance adopted by the present invention can be finely matched and designed, and differentiated damping coefficients can be designed for different travel stages to meet higher requirements for buffering performance.

[0018] (3) The present invention adopts a one-way pressure-limiting structure, which improves the buffering performance while also correspondingly improving the load-bearing capacity of the mechanism itself. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the overall structure of this patent;

[0020] Figure 2 for Figure 1 A cross-sectional view of

[0021] Figure 3 for Figure 2 A partial enlarged schematic diagram of . DETAILED DESCRIPTION

[0022] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be further described in detail below with reference to the accompanying drawings.

[0023] The present application embodiment discloses a self-expanding multi-stage telescopic variable damping mechanism, such as Figure 1 and Figure 2 As shown, it includes a large end support ear 1, a spring seat 2, a damping rod 3-1, a damping cylinder 4-1, a primary damping assembly 3, a secondary damping assembly 4, an outer cylinder 5, a small end support ear 6, an oil tank piston 7, an oil tank 8, a one-way pressure limiting assembly 9 and an oil tank base 10.

[0024] The large end support ear 1 is provided with an internal cavity, the large end support ear 1 is fixed to one end of the outer tube 5 by screw connection, the internal space of the outer tube 5 is communicated with the internal cavity of the large end support ear 1, the damping tube 4-1 is slidably connected to the inside of the outer tube 5, the secondary damping assembly 4 is connected to the end of the outer wall surface of the damping tube 4-1 close to the large end support ear 1, and a sealing assembly is arranged between the end of the outer tube 5 away from the large end support ear 1 and the damping tube 4-1; the damping rod 3-1 is slidably connected in the damping tube 4-1, the secondary damping assembly 4 is connected to the end of the damping rod 3-1 close to the large end support ear 1, and a sealing assembly is arranged between the end of the damping tube 4-1 away from the large end support ear 1 and the damping rod 3-1, and the end of the damping rod 3-1 away from the large end support ear 1 is screwed to the small end support ear 6. At least one of the small end support ear 6 and the large end support ear 1 is connected to a component that needs to be buffered. The spring seat 2 is embedded in the internal cavity of the large end support ear 1, and the left end of the spring seat 2 is directly opposite to the end of the damping cylinder 4-1. A first spring is arranged in the spring seat 2, and one end of the first spring contacts the inside of the spring seat 2, and the other end contacts the inner wall surface of the internal cavity of the large end support ear 1 away from the small end support ear 6, so as to give the damping cylinder 4-1 an initial driving force to extend, and has a certain active expansion function. The spring seat 2 has a weight reduction hole. A locking tool is arranged between the left end of the outer cylinder 5 and the small end support ear 6, which is used to lock the damping structure of this patent in the initial state. When the damping mechanism of this scheme is connected with other parts of the landing mechanism and locked, the locking tool of the damping mechanism is opened to release the lock of the initial driving force, so as to ensure that after the landing mechanism is unlocked, the initial driving force of the damping mechanism can expand other parts of the landing mechanism.

[0025] The oil tank base 10 is connected to the large end lug 1 by flange or bolts, and the oil tank 8 is screwed to the oil tank base 10; the one-way pressure limiting component 9 is connected to the outlet of the oil tank 8, and is used to play a damping role in the process of the oil in the internal cavity of the large end lug 1 flowing into the oil tank 8, so as to reduce the flow rate of the oil and play a one-way pressure limiting role. The oil tank piston 7 is embedded in the internal cavity of the oil tank 8, and the space between the oil tank piston 7 and the one-way pressure limiting component 9 is the storage space for the oil. When the oil in the oil tank 8 flows into the internal cavity of the large end lug 1 through the one-way pressure limiting component 9, the oil tank piston 7 moves in the direction close to the one-way pressure limiting component 9 in the oil tank 8, and vice versa. Move away from 9.

[0026] The primary damping assembly 3 includes a primary plug screw 3-3 and a plurality of primary damping holes 3-2 arranged on the primary plug screw 3-3. The primary plug screw 3-3 is threadedly fixed to the end of the damping rod 3-1 near the large end lug 1. The primary plug screw 3-3 is cylindrical. The outer diameter of the primary plug screw 3-3 matches the damping cylinder 4-1. The primary damping holes 3-2 connect the two sides of the primary plug screw 3-3 along its own axis. The secondary damping assembly 4 includes a secondary plug screw 4-3 and a plurality of secondary damping holes 4-2 opened on the secondary plug screw 4-3. The secondary plug screw 4-3 is threadedly connected to the end of the outer wall of the damping cylinder 4-1 near the large end lug 1. The outer diameter of the secondary plug screw 4-3 matches the inner wall of the outer cylinder 5. The secondary damping holes 4-2 connect the two sides of the secondary plug screw 4-3 along its own axis.

[0027] like Figure 3 As shown, the one-way pressure limiting assembly 9 is composed of a pressure limiting spring 9-1, a pressure limiting member 9-2, a pressure relief groove 9-2-1, a pressure limiting damping hole 9-2-2, a steel ball 9-3, a pressure limiting piston 9-4, a flow groove 9-4-1, and a spring sleeve 9-5.

[0028] The oil tank base 10 is provided with a transverse connecting through hole and a longitudinal connecting through hole. The transverse connecting through hole is parallel to the length direction of the oil tank 8, and one end is connected to the inner cavity of the oil tank 8, and the other end is connected to the internal cavity of the large-end support ear 1 through the longitudinal connecting through hole; the end of the transverse connecting through hole away from the longitudinal connecting through hole is a connecting hole, the diameter of the connecting hole is larger than the diameter of the transverse connecting through hole, and a step surface is formed between the connecting hole and the transverse connecting through hole. The pressure-limiting piston 9-4 is cylindrical, and the outer cylindrical surface of the pressure-limiting piston 9-4 cooperates with the cylindrical surface of the transverse connecting through hole. The end of the pressure-limiting piston 9-4 away from the longitudinal connecting through hole is provided with a first flange on the outside , the end of the first flange contacts the step surface, and the pressure-limiting piston 9-4 is fixedly connected to the oil tank base 10; the inner wall surface of the pressure-limiting piston 9-4 is provided with a plurality of flow grooves 9-4-1 along the circumferential direction, and the flow grooves 9-4-1 penetrate the pressure-limiting piston 9-4 along the axial direction of the pressure-limiting piston 9-4, and the end of the inner wall surface of the pressure-limiting piston 9-4 away from the first flange is connected to a limiting portion, and the steel ball 9-3 is located in the pressure-limiting piston 9-4 and on the side of the limiting portion facing the first flange. The limiting portion is used to limit the steel ball 9-3. When the steel ball 9-3 moves to contact with the limiting portion, it cannot continue to move in the direction close to the longitudinal connecting through hole. The end of the oil tank 8 is inserted into the connecting hole of the oil tank base 10, and the spring sleeve 9-5 is inserted into the end of the oil tank 8 extending into the connecting hole. A convex edge is arranged on the outside of one end of the spring sleeve 9-5 close to the pressure-limiting piston 9-4, and the outer diameter of the convex edge matches the inner wall of the connecting hole. The convex edge is located on the side of the oil tank 8 facing the pressure-limiting piston 9-4, and a through hole is arranged in the middle of the other end of the spring sleeve 9-5. The pressure limiting member 9-2 is a cylindrical structure, which is inserted into the pressure limiting piston 9-4 and is slidably connected to the pressure limiting piston 9-4 along the axial direction of the pressure limiting piston 9-4. The diameter of the steel ball 9-3 is larger than the inner diameter of the pressure limiting member 9-2, and the steel ball 9-3 is located between the limiting portion and the pressure limiting member 9-2; a plurality of pressure relief grooves 9-2-1 are circumferentially arranged on the outer wall surface of the pressure limiting member 9-2, and the pressure relief grooves 9-2-1 are distributed along the radial direction of the pressure limiting member 9-2; the pressure limiting member 9-2 is provided with a plurality of pressure limiting damping holes 9-2-2, and the pressure limiting damping holes 9-2-2 extend from the inner wall surface of the pressure limiting member 9-2 to the outer wall surface, and one end of the pressure limiting damping hole 9-2-2 is connected to the pressure relief groove 9-2-1; the cross-sectional area of ​​a single flow groove 9-4-1 is larger than the hole area of ​​a single pressure limiting damping hole 9-2-2, and the flow in the flow groove 9-4-1 does not generate a damping force. The end of the pressure limiting member 9-2 away from the steel ball 9-3 is connected with a second flange, the second flange is located on the side of the first flange away from the steel ball 9-3, the outer diameter of the second flange is smaller than the inner diameter of the connecting hole, the pressure limiting spring 9-1 is installed in the spring sleeve 9-5, one end of the pressure limiting spring 9-1 contacts the pressure limiting member 9-2, and the other end contacts the inner wall of the end of the spring sleeve 9-5 away from the pressure limiting member 9-2, so that the pressure limiting member 9-2 is subjected to the elastic force of the pressure limiting spring 9-1; the spring sleeve 9-5 is constrained and limited by the spring force after the compression of the pressure limiting spring 9-1 and the installation of the oil tank 8. The spring seat 2 can provide a space for the installation of the push spring and a push guide function.

[0029] The primary damping assembly 3 can provide the damping characteristics and buffering function of the damping rod 3-1 in both the telescopic and extension directions; the main working principle is as follows:

[0030] a. During the extension and retraction process of the damping rod 3-1, the flow restriction of the primary damping hole causes a pressure difference to be generated on both sides of the primary damping hole, thereby generating a damping force;

[0031] b. According to design requirements, several primary damping holes 3-2 on the primary screw plug 3-3 can be installed with plugging screws, so as to change the flow damping area of ​​the primary screw plug 3-3, thereby achieving the designed damping buffering effect.

[0032] The secondary damping assembly 4 can provide the damping characteristics and buffering function of the damping cylinder 4-1 in both the extension and retraction directions; the main working principle is as follows:

[0033] a. During the expansion and contraction of the damping cylinder 4-1, the flow restriction of the secondary damping hole causes a pressure difference to be generated on both sides of the secondary damping hole, thereby generating a damping force;

[0034] b. According to design requirements, several secondary damping holes 4-2 on the secondary screw plug 4-3 can be installed with plugging screws, so as to change the flow damping area of ​​the secondary screw plug 4-3, thereby achieving the designed damping buffering effect.

[0035] The one-way pressure limiting component 9 can provide different damping characteristics and buffering effects in the extension and contraction directions. The main working principles are as follows:

[0036] a. When the damping rod 3-1 and / or the damping cylinder 4-1 are extended, the oil in the oil tank 8 flows into the inside of the large end support ear 6 through the one-way pressure limiting component 9. At this time, the steel ball 9-3 is separated from the end of the pressure limiting component 9-2 due to the effect of the hydraulic force. At this time, the oil flows into the internal cavity of the large end support ear 1 and the internal volume of the outer cylinder 5 through the middle through hole of the spring sleeve 9-5, the middle channel of the pressure limiting component 9-2, and the pressure relief groove 9-2-1 in sequence. At this time, the pressure limiting component 9-2 does not generate damping force, and the damping force comes from the primary damping component and the secondary damping component, and the steel ball 9-3 does not move until it contacts the limit part;

[0037] b. When the damping rod 3-1 and / or the damping cylinder 4-1 are retracted, the oil in the oil tank 8 flows into the one-way pressure limiting component 9 through the internal space of the large end support ear 1. At this time, the steel ball 9-3 is tightly fitted with the end of the pressure limiting component 9-2 due to the effect of the hydraulic force, and the oil flows into the oil tank through the pressure limiting damping hole 9-2-2 on the pressure limiting component 9-2. Due to the effect of the pressure limiting damping hole 9-2-2, the pressure limiting component 9-2 generates a damping force. Therefore, the damping force at this time comes from the primary damping component, the secondary damping component and the pressure limiting component. The combined effect of the three components 9-2 makes the process a pressure-limiting process; when the damping force generated by the oil flow is large, the steel ball 9-3 pushes the pressure-limiting component 9-2 to compress the pressure-limiting spring 9-1 for a certain distance, so that the second flange is separated from the first flange. At this time, the oil passes through the pressure relief groove 9-2-1, between the first flange and the second flange, flows into the connecting hole, and then flows into the oil tank 8 from the through hole at the other end of the spring sleeve 9-5. This process is a pressure relief process; the above-mentioned pressure-limiting process and pressure relief process are performed alternately.

[0038] The implementation principle of this patent is:

[0039] This patent can be applied to the landing buffer mechanism of the launch vehicle network recovery, which includes a damping mechanism, an arresting mechanism, and a connection unlocking mechanism. The large end lug 1 of the damping mechanism is hingedly connected to the rocket body, and the small end lug 6 is hingedly connected to the lug set in the middle of the arresting mechanism; the lug joint is set at the root of the arresting mechanism and is hingedly connected to the rocket body; the connection unlocking mechanism is used to unlock the connection between the arresting mechanism and the rocket body, and is installed on the wall of the rocket body.

[0040] When the landing buffer mechanism is in the initial locked state, the arresting mechanism is initially locked to the outer wall of the rocket body by connecting the unlocking mechanism, and the angle between it and the central axis of the rocket body is less than 5°; the damping mechanism is in the fully retracted state.

[0041] When the landing buffer mechanism needs to deploy and capture the rocket body, the arresting mechanism is unlocked by the connecting unlocking mechanism, and the initial driving force of the damping mechanism pushes the arresting mechanism open to achieve rotational deployment. During the rotational deployment and capture process of the arresting mechanism, the damping mechanism realizes the damping buffering function.

[0042] The contents not described in detail in this application specification belong to the common knowledge of those skilled in the art.

[0043] The present application is described in detail above in conjunction with specific implementation methods and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that, without departing from the spirit and scope of the present application, a variety of equivalent replacements, modifications or improvements can be made to the technical solution of the present application and its implementation methods, all of which fall within the scope of the present application. The scope of protection of the present application shall be subject to the attached claims.

Claims

1. A self-expanding multi-stage telescopic variable damping mechanism, characterized in that: The invention comprises a large end support ear (1), a damping rod (3-1), a damping cylinder (4-1), an outer cylinder (5), a primary damping assembly (3), a secondary damping assembly (4), a small end support ear (6) and an oil tank (8); the large end support ear (1) is provided with an internal cavity; one end of the outer cylinder (5) is connected to the large end support ear (1); the interior of the outer cylinder (5) is communicated with the internal cavity of the large end support ear (1); the damping cylinder (4-1) is slidably connected to the interior of the outer cylinder (5); the secondary damping assembly (4) is connected to one end of the outer wall of the damping cylinder (4-1) close to the large end support ear (1); the damping rod (3-1) is slidably connected to the damping cylinder (4-1); In the cylinder (4-1), a secondary damping assembly (4) is connected to an end of the damping rod (3-1) close to the large end lug (1), an end of the damping rod (3-1) away from the large end lug (1) is connected to the small end lug (6), a sealing assembly is provided between the end of the outer cylinder (5) away from the large end lug (1) and the damping cylinder (4-1), and between an end of the damping cylinder (4-1) away from the large end lug (1) and the damping rod (3-1); an oil tank (8) is connected to the internal cavity of the large end lug (1); and at least one of the small end lug (6) and the large end lug (1) is connected to a component that needs to be buffered.

2. A self-deployable multi-stage telescopic variable damping mechanism according to claim 1, characterized in that: A spring seat (2) and a first spring are arranged in the internal cavity of the large end support ear (1); the left end of the spring seat (2) is directly opposite to the end of the damping cylinder (4-1); one end of the first spring is in contact with the inside of the spring seat (2), and the other end is in contact with the inner wall surface of the internal cavity of the large end support ear (1) away from the small end support ear (6).

3. The self-expanding multi-stage telescopic variable damping mechanism according to claim 1, characterized in that: The primary damping assembly (3) comprises a primary screw plug (3-3) and a plurality of primary damping holes (3-2) arranged on the primary screw plug (3-3); the primary screw plug (3-3) is threadedly fixed to the end of the damping rod (3-1) close to the large end support ear (1); the primary screw plug (3-3) is cylindrical, the outer diameter of the primary screw plug (3-3) matches the damping cylinder (4-1), and the primary damping holes (3-2) are connected to both sides of the primary screw plug (3-3) along its own axial direction.

4. The self-expanding multi-stage telescopic variable damping mechanism according to claim 1, characterized in that: The secondary damping assembly (4) comprises a secondary screw plug (4-3) and a plurality of secondary damping holes (4-2) formed on the secondary screw plug (4-3); the secondary screw plug (4-3) is threadedly connected to the end of the outer wall of the damping cylinder (4-1) close to the large end support ear (1); the outer diameter of the secondary screw plug (4-3) matches the inner wall of the outer cylinder (5); and the secondary damping holes (4-2) are connected to both sides of the secondary screw plug (4-3) along its own axis.

5. The self-expanding multi-stage telescopic variable damping mechanism according to claim 1, characterized in that: The oil tank (8) is connected to the large end lug (1) via an oil tank base (10); a one-way pressure limiting component (9) is connected to the outlet of the oil tank (8) to provide a damping effect when oil in the internal cavity of the large end lug (1) flows into the oil tank (8); an oil tank piston (7) is provided in the oil tank (8); the space between the oil tank piston (7) and the one-way pressure limiting component (9) is a storage space for oil; when the oil in the oil tank (8) flows into the internal cavity of the large end lug (1) through the one-way pressure limiting component (9), the oil tank piston (7) moves in the oil tank (8) in a direction close to the one-way pressure limiting component (9), and vice versa, moves in a direction away from the one-way pressure limiting component (9).

6. The self-expanding multi-stage telescopic variable damping mechanism according to claim 1, characterized in that: The one-way pressure-limiting assembly (9) comprises a spring sleeve (9-5), a pressure-limiting spring (9-1), a pressure-limiting piece (9-2), a steel ball (9-3) and a pressure-limiting piston (9-4); the oil tank base (10) is provided with a transverse connecting through hole and a longitudinal connecting through hole; the transverse connecting through hole is parallel to the length direction of the oil tank (8), one end of which is connected to the inner cavity of the oil tank (8), and the other end of which is connected to the inner cavity of the large-end support ear (1) through the longitudinal connecting through hole; the end of the transverse connecting through hole away from the longitudinal connecting through hole is a connecting hole, and the diameter of the connecting hole is larger than the diameter of the transverse connecting through hole; the outlet of the oil tank (8) is installed in the connecting hole, the spring sleeve (9-5) is installed in the outlet of the oil tank (8), the pressure-limiting piston (9-4) is fixedly connected to the transverse connecting through hole, and the pressure-limiting piece (9-5) is fixedly connected to the transverse connecting through hole. (9-2) is located in the connecting hole and between the outlet of the oil tank (8) and the pressure-limiting piston (9-4); the pressure-limiting spring (9-1) is located in the spring sleeve (9-5) and is used to push the pressure-limiting member (9-2); the steel ball (9-3) is located in the pressure-limiting piston (9-4); the space between the steel ball (9-3) and the pressure-limiting piston (9-4) is used for oil to pass through; the diameter of the steel ball (9-3) is larger than the inner diameter of the pressure-limiting member (9-2) toward one end of the steel ball; the pressure-limiting member (9-2) is provided with a pressure-limiting damping hole (9-2-2) so that after the steel ball (9-3) blocks the end of the pressure-limiting member (9-2), the oil can enter the spring sleeve (9-5) through the pressure-limiting damping hole (9-2-2); and the end of the spring sleeve (9-5) away from the pressure-limiting member (9-2) is a through hole.

7. The self-expanding multi-stage telescopic variable damping mechanism according to claim 6, characterized in that: The inner wall surface of the pressure-limiting piston (9-4) is provided with a plurality of flow grooves (9-4-1) along the circumferential direction.

8. The self-expanding multi-stage telescopic variable damping mechanism according to claim 6, characterized in that: The end of the inner wall surface of the pressure-limiting piston (9-4) away from the first flange is connected to the limiting portion, and the steel ball (9-3) is located on the side of the limiting portion facing the pressure-limiting member (9-2).

9. The self-expanding multi-stage telescopic variable damping mechanism according to claim 6, characterized in that: The pressure limiting member (9-2) is a cylindrical structure. The pressure limiting member (9-2) is inserted into the pressure limiting piston (9-4) and is slidably connected to the pressure limiting piston (9-4) along the axial direction of the pressure limiting piston (9-4). A plurality of pressure relief grooves (9-2-1) are arranged along the circumferential direction on the outer wall surface of the pressure limiting member (9-2). The pressure relief grooves (9-2-1) are distributed along the radial direction of the pressure limiting member (9-2). The pressure limiting damping hole (9-2-2) penetrates from the inner wall surface to the outer wall surface of the pressure limiting member (9-2), and one end of the pressure limiting damping hole (9-2-2) is connected to the pressure relief groove (9-2-1).

10. The self-expanding multi-stage telescopic variable damping mechanism according to claim 6, characterized in that: A first flange is arranged on the outside of one end of the pressure-limiting piston (9-4) away from the longitudinal connecting through hole, a step surface is formed between the connecting hole and the transverse connecting through hole, and the end of the first flange contacts the step surface; a second flange is connected to one end of the pressure-limiting member (9-2) away from the steel ball (9-3), the second flange is located on the side of the first flange away from the steel ball (9-3), and the outer diameter of the second flange is smaller than the inner diameter of the connecting hole.

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