A dual-cylinder three-chamber gas-bearing shock absorber

Abstract

The application discloses a double-cylinder three-cavity gas-bearing shock absorber, which is characterized by comprising an upper cylinder and a lower cylinder; the lower cylinder is inserted into the upper cylinder at the upper part, and an upper gas cavity is formed in the upper cylinder; a sealing guide assembly is arranged in the upper part of the lower cylinder; a main piston and a floating piston are arranged in the lower cylinder and are spaced apart from each other; the main piston is coaxially fixed to the top of the upper cylinder through a piston rod; an oil cavity is formed in the lower cylinder between the sealing guide assembly and the floating piston, and a damping hole is arranged on the main piston; a lower gas cavity is formed in the lower cylinder between the floating piston and the bottom of the lower cylinder. The piston rod of the shock absorber is closed motion, and is coaxial linear motion during expansion and contraction, so that the oil leakage defect is solved from the root, the upper gas cavity is used as the main force bearing, the comfort is improved by using the nonlinear compression characteristics of the gas, and the double-gas-cavity independent pressure regulation is used to adapt to multiple working conditions.

Description

Technical Field

[0001] This invention relates to a dual-cylinder, three-chamber air-bearing shock absorber. Background Technology

[0002] Vehicle shock absorbers are crucial to a vehicle's handling performance and ride comfort. (See also...) Figure 1 The image shows a conventional hydraulic shock absorber, which relies on the reciprocating sliding of the piston rod relative to the cylinder to compress the shock absorber oil in the upper and lower oil chambers. The oil then passes through the damping orifice to generate damping, thus achieving a shock absorption effect. However, this product has the following shortcomings in actual use: First, there's the issue of oil leakage. In traditional shock absorbers, the end hole at the top of the cylinder through which the piston rod passes is directly open to the outside environment, allowing dust and other contaminants to easily enter the oil seal area, leading to oil leakage. Additionally, due to the spring's structure, its upper and lower contact ends are not parallel, resulting in single-point contact. This causes the spring to tilt to one side during extension and retraction, generating radial eccentric force. This causes uneven wear between the piston rod and the oil seal (or sealing ring), resulting in one-sided wear, oil leakage, and a significant reduction in lifespan. Secondly, the stiffness characteristics are not adjustable and the ride comfort is poor. Traditional shock absorbers rely on external springs for main support, and the stiffness is linear, meaning that the spring's deformation force increases linearly with the compression. When a vehicle rebounds after driving over large potholes, it experiences a near-rigid impact, resulting in a harsh ride and poor comfort. Furthermore, external springs are bulky and heavy, hindering weight reduction. Third, it has poor versatility and cannot adapt to various working conditions. After traditional shock absorbers are assembled, their damping holes and spring dimensions cannot be adjusted, and their support stiffness and damping parameters remain unchanged, making them unable to adapt to various load conditions such as no-load, light-load, and heavy-load.

[0003] The closest existing patent found to this application, CN211693332U (with CN111120563A filed on the same day), is a single-cylinder, two-oil-one-chamber structure designed to address issues of air bubbles, heat generation, and noise caused by oil-air mixing. This patent's internal air chamber is only used to compensate for oil volume, serving only an auxiliary elastic function; its essence remains the conventional hydraulic damping principle. This patent, being a single-cylinder structure, leaves the piston rod's end hole at the top of the cylinder exposed, unable to prevent external impurities from corroding it, and prone to oil seal wear and leakage—common problems. Furthermore, the single lower air chamber prevents independent pressure regulation of the upper and lower chambers. Adjusting the air pressure in the lower chamber, which serves as a compensation function, primarily alters the reset performance, with little effect on improving damping support and overall damping performance. Summary of the Invention

[0004] This application addresses several technical shortcomings of existing conventional hydraulic shock absorbers, including frequent oil leaks, significant oil seal wear, linear spring support stiffness leading to poor ride comfort, non-adjustable damping parameters, difficulty in adapting to various load conditions, and the fact that even the closest prior art patents (CN211693332U or CN111120563A) fail to resolve the oil leakage issue and offer only minor performance improvements through lower air chamber pressure adjustment for compensation. This application provides a dual-cylinder, three-chamber air-bearing shock absorber that overcomes all the aforementioned defects of existing technologies, thus resolving these multiple pain points of traditional shock absorbers.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a dual-cylinder, three-chamber air-bearing shock absorber, characterized in that it comprises an upper cylinder and a lower cylinder arranged coaxially; the upper part of the lower cylinder extends into the upper cylinder and is slidably fitted in a sealed manner; an upper air chamber is formed inside the upper cylinder and its volume changes with the up-and-down movement of the upper cylinder; a sealing guide assembly is fixedly installed inside the upper part of the lower cylinder; an active piston and a floating piston are slidably fitted in a sealed manner inside the lower cylinder; the active piston and the floating piston are spaced apart vertically; the active piston is coaxially fixed to the top of the upper cylinder via a piston rod; the piston rod is slidably fitted in a sealed manner with the sealing guide assembly; a middle oil chamber is formed inside the lower cylinder between the sealing guide assembly and the floating piston, and a damping hole extending vertically through the active piston is opened on the active piston; a lower air chamber is formed inside the lower cylinder between the floating piston and the bottom of the lower cylinder; the middle oil chamber is filled with shock absorber oil; and both the upper and lower air chambers are filled with pressurized gas.

[0006] Using the above technical solution, during operation, the upper air chamber is filled with pressurized gas and serves as the main load-bearing air chamber, responsible for supporting the vehicle body load and nonlinear buffering. It mainly determines the shock absorber's load-bearing capacity, stiffness, and impact resistance. The middle oil chamber is a damping oil chamber, which is used for damping and absorbing shocks. The lower air chamber is a compensation air chamber, which is used for the floating piston reset and oil volume compensation. Because the upper and lower air chambers are set separately, they can be independently inflated and pressurized. The air pressure in the upper air chamber changes to adjust the performance of the support (load-bearing) stiffness and buffer characteristics; while the air pressure in the lower air chamber changes to adjust the performance of the floating piston reset force and volume compensation pressure, thus adapting to various working conditions such as light load, full load, and heavy load. Because the piston rod is entirely housed inside both the upper and lower cylinders, and the mating area between the piston rod and the upper part of the lower cylinder is within a closed upper air chamber, isolated from the outside, the working environment between the piston rod and the sealing guide assembly is improved. This prevents dust and sediment from entering the piston rod's moving area, avoiding oil leakage caused by dust and sediment. Simultaneously, the lower cylinder extends into the upper cylinder and slides in a sealed manner, forming an external coaxial guide structure. Furthermore, the active piston and floating piston inside the lower cylinder slide in a sealed manner against the inner wall of the cylinder, and the precise fit between the piston rod and the sealing guide assembly forms an internal coaxial guide structure. This combination creates a double coaxial guide system, ensuring the coaxial linear transmission of all extension and retraction movements of the shock absorber. This completely eliminates radial offset and eccentric swaying, resulting in smoother and more stable component movement, effectively reducing wear on the sealing guide components, and ensuring the long-term working accuracy and stability of the shock absorber. Therefore, this solution addresses the root cause of oil leakage, improves comfort, and increases the versatility of the shock absorber.

[0007] Furthermore, a first air nozzle is installed on the top of the upper cylinder, which is used to individually adjust the pressure by filling or deflating the upper air chamber; a second air nozzle is installed on the bottom of the lower cylinder, which is used to individually adjust the pressure by filling or deflating the lower air chamber.

[0008] Furthermore, the upper and lower air chambers are filled with gaseous media such as nitrogen or air.

[0009] Furthermore, the bottom of the upper cylinder is provided with a sliding hole for clearance fit with the upper part of the lower cylinder and a first sealing ring for interference fit with the lower cylinder.

[0010] Furthermore, the sealing guide assembly includes a guide sleeve and a second sealing ring; the guide sleeve is clearance-fitted with the piston rod; the second sealing ring and the piston rod are interference-fitted.

[0011] Furthermore, the lower end of the piston rod is coaxially fixed to the active piston, and its upper end is coaxially fixed to the top of the upper cylinder.

[0012] Furthermore, a recoil body is fitted onto the piston rod; the lower end of the recoil body is in contact with the upper part of the lower cylinder.

[0013] Furthermore, the recoil body is made of polyurethane or hydrogenated nitrile butadiene material.

[0014] Furthermore, a buffer ring is fitted onto the piston rod; and the buffer ring is located between the sealing guide assembly and the active piston.

[0015] Furthermore, a third sealing ring is installed on the active piston; a fourth sealing ring is installed on the floating piston.

[0016] Compared with the prior art, the present invention has the following significant advantages: First, this invention employs a double-cylinder design with a larger upper cylinder and a smaller lower cylinder, a three-chamber configuration with an upper air chamber for oil and a lower air chamber, and uses non-spring support. The upper cylinder has a larger inner diameter and the largest effective load-bearing area. The upper air chamber N-1 is the main load-bearing air chamber, responsible for supporting the vehicle body load. The air pressure and volume of the upper air chamber are inversely proportional, exhibiting non-linear stiffness characteristics (see [reference]). Figure 5 This invention achieves a soft feel in small impacts and a strong feel in large impacts: During small vibrations, the softer support stiffness gently absorbs minor road vibrations, preventing harsh transmission of vibrations to the vehicle body; during large vibrations, the stiffness increases dramatically in the latter part, powerfully resisting impacts and effectively damping and absorbing shocks, thus improving comfort. The middle oil chamber is a damping oil chamber, its function being damping and shock absorption; the lower air chamber is a compensation air chamber, responsible for the floating piston's reset and oil volume compensation. Therefore, it solves the technical problem of linear spring support stiffness resulting in poor ride comfort. Furthermore, this invention replaces the traditional spring support method of shock absorbers, achieving spring-free shock absorption. By completely eliminating the bulky and heavy external metal spring, the overall size and weight of the shock absorber can be reduced. Secondly, this invention features separate upper and lower air chambers, allowing for independent inflation and pressure adjustment. Specifically, adjusting the upper air chamber pressure via the first air nozzle 5 allows for adaptation to different load support requirements and adjustment of the shock absorber's stiffness; adjusting the lower air chamber pressure via the second air nozzle 6 controls the floating piston's reset speed and compensation pressure, adapting to different road conditions. In use, changes in the upper air chamber pressure adjust the support (load-bearing) stiffness and buffering characteristics; changes in the lower air chamber pressure adjust the floating piston's reset force and volume compensation pressure. Either parameter can be adjusted, or both parameters can be adjusted simultaneously, thus adapting to various working conditions such as light load, full load, and heavy load. Therefore, this invention solves the existing technical problem of difficulty in adapting to multiple load conditions. Third, this invention features a piston rod that is entirely housed within both the upper and lower cylinders. The mating area between the piston rod and the upper part of the lower cylinder is located within a closed upper air chamber, isolated from the outside. This improves the working environment between the piston rod and the sealing guide assembly, preventing dust and sediment from entering the piston rod's movement area and avoiding oil leakage caused by dust and sediment. Simultaneously, the lower cylinder extends into the upper cylinder and slides in a sealed manner, forming an external coaxial guide structure. Furthermore, the active piston and floating piston inside the lower cylinder slide in a sealed manner against the inner wall of the cylinder, and the precise fit between the piston rod and the sealing guide assembly forms an internal coaxial guide structure. This combination creates a double coaxial guide system, ensuring that all extension and retraction movements of the shock absorber are transmitted coaxially, completely eliminating radial offset and eccentric sway. This results in smoother and more stable component movement, effectively reducing wear on the sealing guide components and ensuring the long-term working accuracy and stability of the shock absorber. Therefore, this invention addresses the root cause of oil leakage, improves comfort, and increases the versatility of the shock absorber. Fourth, the present invention uses a buffer ring to effectively buffer rigid impacts when the active piston moves upward to its limit position, assisting in shock absorption and preventing the active piston from directly impacting the sealing guide assembly, thus providing upward overload protection; and uses a recoil body to effectively buffer rigid impacts when the shock absorber is at its limit compression stroke, assisting in shock absorption and preventing direct collision damage to the cylinder and piston structure, thus providing downward overload protection. Attached Figure Description

[0017] Figure 1 A schematic diagram of the structure of an existing hydraulic shock absorber.

[0018] Figure 2 A schematic diagram of the structure of a dual-cylinder, three-chamber air-bearing shock absorber in normal operation according to the present invention.

[0019] Figure 3 A schematic diagram of the structure of a dual-cylinder, three-chamber air-bearing shock absorber during compression in this invention. Figure 4 This invention provides a schematic diagram of the structure of a dual-cylinder, three-chamber air-bearing shock absorber when the upper end of the recoil body contacts the inner side of the top of the upper cylinder due to excessive compression stroke. Figure 5 The performance test results of the dual-cylinder three-chamber air-bearing shock absorber of the present invention and the existing hydraulic shock absorber are compared by the applied pressure-compression (FS) relationship graph.

[0020] The markings in the diagram are: 1 Upper cylinder, 1-1 Sliding hole, 2 Lower cylinder, 3 Active piston, 3-1 Damping hole, 4 Floating piston, 5 First air nozzle, 6 Second air nozzle, 7 First sealing ring, 8 Sealing guide assembly, 8 Guide sleeve, 9 Second sealing ring, 10 Recoil body, 11 Buffer ring, 12 Piston rod, 13 Third sealing ring, 14 Fourth sealing ring, N-1 Upper air chamber, N-2 Middle oil chamber, N-3 Lower air chamber. Detailed Implementation

[0021] The present invention will now be described in conjunction with the accompanying drawings and embodiments: Example 1: See Figure 2-4 A dual-cylinder, three-chamber air-bearing shock absorber includes an upper cylinder 1 and a lower cylinder 2 coaxially mounted. The inner diameter of the upper cylinder 1 is larger than the inner diameter of the lower cylinder 2. The upper part of the lower cylinder 2 extends vertically into the interior of the upper cylinder 1 and is sealed to the bottom of the upper cylinder 1, and the two are slidably fitted together.

[0022] Specifically, the bottom of the upper cylinder 1 is provided with a sliding hole 1-1, which is clearance-fitted with the lower cylinder 2 (e.g., tolerance H7 / g6) to ensure that the lower cylinder 2 can smoothly slide relative to the upper cylinder 1. Simultaneously, a first sealing ring 7 is embedded in the bottom of the upper cylinder 1. The first sealing ring 7 (e.g., an oil seal) is elastically interference-fitted with the outer wall of the lower cylinder 2 to achieve sealing protection at the mating position of the upper and lower cylinders, preventing impurities from entering the internal cavity. Furthermore, a dust cover can be fitted over the bottom of the upper cylinder 1 to prevent dust and sand from the outer surface of the lower cylinder 2 from entering the sliding hole 1-1 during relative sliding.

[0023] See Figure 2-4 The upper cylinder 1 is closed at the top, and the interior of the upper cylinder 1 forms a closed upper air chamber N-1. The volume of the upper air chamber N-1 can dynamically change with the relative extension and retraction of the upper cylinder 1 and the lower cylinder 2.

[0024] See Figure 2-4 A first air nozzle 5 is fixedly installed on the top of the upper cylinder 1. The first air nozzle 5 is connected to the upper air chamber N-1. The upper air chamber N-1 can be charged or depressurized independently through the first air nozzle 5 to achieve independent adjustment of the air pressure inside the upper air chamber N-1, thereby changing the load-bearing stiffness and buffering performance of the shock absorber.

[0025] See Figure 2-4 A sealing guide assembly is fixedly installed in the upper inner cavity of the lower cylinder 2. The sealing guide assembly includes a guide sleeve 8 and a second sealing ring 9. The guide sleeve 8 is clearance-fitted with the piston rod 12 (e.g., tolerance H7 / g6) to provide precise guidance for the reciprocating motion of the piston rod 12. The second sealing ring 9 (elastic material) is elastically interference-fitted with the outer wall of the piston rod 12 to achieve dynamic sealing of the sliding position of the piston rod 12 and prevent oil and gas leakage.

[0026] See Figure 2-4 The lower cylinder 2 contains a slidingly fitted, sealed active piston 3 and a floating piston 4. Specifically, the active piston 3 is sealed to the inner wall of the lower cylinder 2 and can slide relative to it, as is the floating piston 4. The active piston 3 is located above the floating piston 4 and below the sealing guide assembly 8.

[0027] See Figure 2-4 Specifically, the outer wall of the active piston 3 is nested with a third sealing ring 13 to ensure that the oil can only pass through the damping hole 3-1, and the outer wall of the floating piston 4 is nested with a fourth sealing ring 14 to ensure the sealing and sliding effect between the floating piston 4 and the inner wall of the lower cylinder 2.

[0028] See Figure 2-4The lower end of the piston rod 12 is coaxially and fixedly connected to the active piston 3, and the upper end of the piston rod 12 is coaxially and fixedly connected to the top of the upper cylinder 1. Its rod body passes downward through the sealing guide assembly 8 and extends into the inner cavity of the lower cylinder 2.

[0029] See Figure 2-4 Specifically, the lower cylinder 2 has a central oil chamber N-2 formed between the sealing guide assembly 8 and the floating piston 4. The central oil chamber N-2 is filled with special damping oil, serving as the core cavity for damping. During operation, the active piston 3 slides synchronously with the lifting and lowering movement of the upper cylinder 1. The active piston 3 has vertically penetrating damping holes 3-1, which can be single or multiple, to allow the damping oil in the central oil chamber N-2 to generate damping force and circulate back as the active piston 3 moves up and down. The central oil chamber N-2 is divided into an upper chamber N-21 and a lower chamber N-22 by the active piston 3. When the active piston 3 moves downward, the lower chamber N-22 shrinks, while the upper chamber N-21 expands. The oil in the lower chamber N-22 flows upward from the damping hole 3-1 into the upper chamber N-21 (for comparison). Figure 2-4 When the active piston 3 moves upward, the lower chamber N-22 increases in size, while the upper chamber N-21 decreases in size. Oil in the upper chamber N-21 flows back down from the damping orifice 3-1 into the lower chamber N-22 (see...). Figure 2 When the active piston 3 moves up and down, it generates restoring and compressive damping forces, which consume vibrational energy.

[0030] See Figure 2-4 Specifically, the lower cylinder 2 has a lower air chamber N-3 formed between the floating piston 4 and the bottom of the lower cylinder 2, and the lower air chamber N-3 is a pressure compensation chamber.

[0031] See Figure 2-4 In addition, a second air nozzle 6 is fixedly installed at the bottom of the lower cylinder 2. The second air nozzle 6 is connected to the lower air chamber N-3 and can independently charge and release air to regulate the pressure of the lower air chamber N-3, thereby adjusting the reset spring force of the floating piston 4 and the oil compensation pressure.

[0032] See Figure 2-4In this embodiment, the pressurized gas filled in the upper air chamber N-1 and the lower air chamber N-3 is nitrogen. Nitrogen has stable chemical properties, is not easily oxidized or corroded by the cylinder wall, and is relatively less affected by temperature, thus maintaining stable chamber pressure over a long period and improving product operational stability. In other embodiments, air or other gases can also be used as filling gases (compressed). During operation, the upper air chamber N-1 is filled with pressurized gas (3-8 atmospheres on the gauge), the lower air chamber N-3 is filled with pressurized gas (3-8 atmospheres on the gauge), and the middle oil chamber N-2 is filled with shock absorber oil (or hydraulic oil, etc.). Among them, since the upper cylinder has a larger inner diameter and the greatest effective load-bearing capacity, the upper air chamber N-1 is the main load-bearing air chamber, responsible for supporting the vehicle body load and nonlinear buffering, mainly determining the shock absorber's load-bearing capacity, stiffness, and impact resistance; the middle oil chamber N-2 is a damping oil chamber, whose function is damping and absorbing shocks; the lower air chamber N-3 is a compensation air chamber, whose function is responsible for floating piston reset and oil volume compensation.

[0033] The working principle of this embodiment is as follows: When the vehicle encounters bumpy roads while driving, the upper cylinder 1 reciprocates vertically relative to the lower cylinder 2, causing the piston rod 12 and the active piston 3 to slide up and down synchronously. When the shock absorber is compressed, the upper air chamber N-1 is compressed, and the internal air pressure increases. It utilizes the nonlinear compression characteristics of gas to provide flexible support and buffer the impact of the road surface.

[0034] According to Boyle's Law, under constant temperature operating conditions, the ideal gas within a closed air chamber satisfies the relationship that the product of pressure (P) and volume (V) is a constant C, i.e., PV = C (constant). The volume of the upper air chamber N-1 roughly satisfies the geometric relationship: V = S·H, where S is the effective pressure-bearing area (i.e., the cross-sectional area of ​​the inner bore of the upper cylinder) and H is the effective height (height of the upper air chamber). For the upper air chamber of this shock absorber, the effective pressure-bearing area S is fixed (constant), therefore P·S·H = C. Since S and C are both constants, setting the constant M = C / S, we get P = M / H, an inverse proportional function curve, meaning that the air pressure (pressure) is inversely proportional to the effective height of the air chamber (or a similar inverse proportional relationship).

[0035] When pressure is applied, the high-pressure gas compression process in the upper air chamber N-1 of this embodiment exhibits nonlinear stiffness characteristics (see [reference]). Figure 5Therefore, it can achieve the effect of being soft in small impacts and strong in large impacts: During small vibrations, the support stiffness is relatively soft, which can gently absorb minor vibrations from the road surface, preventing the vibration from being harshly transmitted to the vehicle body; during large vibrations, its stiffness increases sharply in the latter part, which can strongly resist the impact, effectively damping and absorbing shocks, while preventing the shock absorber from hitting the bottom hard. In contrast, the force of the linear spring in a traditional shock absorber (stiffness k is constant) is proportional to the displacement (F=ks), resulting in a significant abrupt change in acceleration during impact. This embodiment uses high-pressure gas inside the upper air chamber N-1 as the main support medium, replacing the spring support method of traditional shock absorbers, achieving springless shock absorption. By completely eliminating the bulky and heavy external metal spring, the overall size and weight of the shock absorber can be effectively reduced.

[0036] In addition, the active piston 3 squeezes the damping oil inside the oil chamber N-2 downwards, and the oil flows upwards through the damping hole 3-1 of the active piston 3, generating damping force to consume vibration energy, thereby achieving the effect of damping and absorbing vibration.

[0037] When the shock absorber rebounds and stretches, the volume of the middle oil chamber N-2 increases and the pressure decreases. The floating piston 4 is pushed upward by the high-pressure gas in the lower air chamber N-3 and compensates for the oil volume in the middle oil chamber N-2.

[0038] See Figure 2-4 The pressure in the upper air chamber N-1 can be adjusted via the first air nozzle 5 to adapt to different load requirements and adjust the damper's stiffness. The pressure in the lower air chamber N-3 can be adjusted via the second air nozzle 6 to control the reset speed and compensation pressure of the floating piston 4, adapting to different road conditions. Because the upper and lower air chambers are separately configured, they can be independently inflated and their pressure adjusted. During use, the performance of the support (load-bearing) stiffness and buffering characteristics can be adjusted by changing the pressure in the upper air chamber; the performance of the floating piston's reset force and volume compensation pressure can be adjusted by changing the pressure in the lower air chamber. Either parameter can be adjusted, or both parameters can be adjusted simultaneously (the pressure ratio between the upper and lower air chambers), thus adapting it to various working conditions such as light load, full load, and heavy load.

[0039] For example, when used under light load conditions, the air pressure in the upper air chamber N-1 can be adjusted to a lower value (e.g., 2-4 atmospheres) to obtain softer support characteristics and lower frequency deviation, thus improving ride comfort. When used under heavy load conditions, the air pressure in the upper air chamber N-1 can be adjusted to a higher value (e.g., 4-6 atmospheres or higher) to obtain stronger support stiffness and higher frequency deviation, ensuring vehicle body stability. The air pressure in the lower air chamber N-3 can be independently adjusted (e.g., 6-10 atmospheres) to accommodate different floating piston 4 reset speeds and compensation support force requirements.

[0040] Therefore, the product in this embodiment can cover the full range of operating conditions from light passenger vehicles to heavy commercial vehicles by adjusting the pressure of the upper and lower air chambers, and can be adapted to different vehicle models without changing the hardware.

[0041] In this embodiment, the lower cylinder 2 extends into the upper cylinder 1 and slides in a sealed manner, forming an external coaxial guiding structure. Simultaneously, the active piston 3 and floating piston 4 inside the lower cylinder 2 slide in a sealed manner with the inner wall of the lower cylinder 2, and the piston rod 12 precisely guides the sealing guide assembly 8, forming an internal coaxial guiding structure. This dual coaxial guidance ensures that all forces during the shock absorber's extension and retraction movements are evenly transmitted along the vertical coaxial direction, greatly suppressing radial offset and eccentric sway. This results in smoother and more stable component movement, effectively reducing wear on seals and guide components, ensuring the long-term working accuracy and stability of the shock absorber, fundamentally improving oil leakage defects, enhancing comfort, and increasing the versatility of the shock absorber.

[0042] Because the piston rod 12 is housed entirely within the upper cylinder 1 and the lower cylinder 2, and the mating area between the piston rod 12 and the upper part of the lower cylinder 2 is within the closed upper air chamber N-1 and not connected to the outside, dust and sand are prevented from entering the piston rod 12's movement area within this sealed space. This improves the working environment between the piston rod 12 and the sealing guide assembly, especially improving the wear environment of the second sealing ring and extending its service life, thus preventing oil leakage caused by dust and sand. Simultaneously, the lower cylinder 2 extends into the upper cylinder 1 and slides in a sealed manner, forming an external coaxial guide structure. Furthermore, the active piston 3 and floating piston 4 inside the lower cylinder 2 slide in a sealed manner with the inner wall of the lower cylinder 2, forming an internal coaxial guide structure in conjunction with the precise fit between the piston rod 12 and the guide sleeve 8. This combination creates a double coaxial guide structure, ensuring the coaxial transmission of all extension and retraction movements of the shock absorber, completely eliminating radial offset and eccentric swaying problems. This results in smoother and more stable component movement, effectively reducing wear on the sealing guide components and ensuring the long-term working accuracy and stability of the shock absorber. Therefore, it addresses the root cause of oil leakage defects, improves comfort, and increases the versatility of shock absorbers.

[0043] Example 2 See Figure 2-4 Based on Example 1, a bidirectional buffer structure was further added, as detailed below: A buffer ring 11 is fitted onto the piston rod 12, and the buffer ring 11 is arranged between the sealing guide assembly 8 and the active piston 3. When the active piston 3 moves upward to its limit position, it can effectively buffer rigid impacts, assist in shock absorption, and prevent the active piston 3 from directly impacting the sealing guide assembly 8 and causing structural damage, thus playing a role in upward overload protection.

[0044] Meanwhile, a recoil body 10 is also fitted onto the piston rod 12. The recoil body 10 is made of polyurethane or hydrogenated nitrile wear-resistant buffer material, and its lower end contacts the upper end face of the lower cylinder 2. During the extreme compression stroke of the shock absorber, it can effectively buffer rigid impacts, assist in shock absorption, and prevent direct collision damage to the cylinder and piston structure, thus playing a role in downward overload protection.

[0045] See Figure 5 Comparing Embodiment 1 and Embodiment 2, it can be seen that: in the normal working zone (0-40mm), the performance of both is basically the same; in the buffer transition zone (40-70mm), the recoil body 10 begins to intervene, and the difference gradually becomes apparent; in the extreme buffer zone (70-80mm), the recoil body 10 begins to play a major role in absorbing energy, and the difference is significant (the force value is significantly higher than that of Embodiment 1). Therefore, under the same extreme compression displacement, Embodiment 2 can provide a higher support reaction force to resist extreme impacts; conversely, when subjected to the same extreme impact load, the compression displacement of Embodiment 2 will be smaller (i.e., less likely to bottom out), providing a greater safety margin for the entire vehicle. Figure 5 In the diagram, P1-10 represent different applied force values ​​(F) to the shock absorber, while S is the compression amount of the shock absorber (i.e., the stroke size x).

[0046] Example 3 This embodiment is basically the same as Embodiment 1 or Embodiment 2, except that the damping structure of the active piston 3 adopts an equivalent replacement scheme.

[0047] Specifically, in this embodiment, a through hole extending vertically is provided on the active piston 3, and a valve plate is fixedly installed above the active piston 3. The valve plate has a damping hole that communicates with the through hole. This embodiment works on the same principle as the scheme in Embodiment 1 or Embodiment 2 where the damping hole 3-1 is directly provided on the active piston 3, and is an equivalent scheme.

Claims

1. A dual-cylinder, three-chamber air-bearing shock absorber, characterized in that, It includes an upper cylinder (1) and a lower cylinder (2) arranged coaxially. The upper part of the lower cylinder (2) extends into the upper cylinder (1) and is slidably fitted in a sealed manner. An upper air chamber (N-1) is formed inside the upper cylinder (1) and its volume changes as the upper cylinder (1) moves up and down. A sealing guide assembly (8,9) is fixedly installed inside the upper part of the lower cylinder (2); an active piston (3) and a floating piston (4) are simultaneously and slidably fitted inside the lower cylinder (2); the active piston (3) and the floating piston (4) are distributed vertically at intervals; the active piston (3) is coaxially fixed to the top of the upper cylinder (1) through a piston rod (12); the piston rod (12) is slidably fitted with the sealing guide assembly (8,9) in a sealing manner; The lower cylinder (2) forms an oil chamber (N-2) between the sealing guide assembly (8,9) and the floating piston (4), and the active piston (3) has a damping hole (3-1) that runs through the vertical direction. The lower cylinder (2) forms a lower air chamber (N-3) between the floating piston (4) and the bottom of the lower cylinder (2); the middle oil chamber (N-2) is filled with shock absorber oil; the upper air chamber (N-1) and the lower air chamber (N-3) are both filled with pressurized gas.

2. The dual-cylinder, three-chamber air-bearing shock absorber according to claim 1, characterized in that, A first air nozzle (5) is installed on the top of the upper cylinder (1), which is used to individually adjust the pressure of the upper air chamber (N-1) by filling or deflating it; a second air nozzle (6) is installed on the bottom of the lower cylinder (2), which is used to individually adjust the pressure of the lower air chamber (N-3) by filling or deflating it.

3. The dual-cylinder, three-chamber air-bearing shock absorber according to claim 1 or 2, characterized in that, The upper air chamber (N-1) and lower air chamber (N-3) are filled with nitrogen or air.

4. The dual-cylinder, three-chamber air-bearing shock absorber according to claim 1, characterized in that: The bottom of the upper cylinder (1) is provided with a sliding hole (1-1) for clearance fit with the upper part of the lower cylinder (2) and a first sealing ring (7) for interference fit with the lower cylinder (2).

5. The dual-cylinder, three-chamber air-bearing shock absorber according to claim 1, characterized in that, The sealing guide assembly includes a guide sleeve (8) and a second sealing ring (9); the guide sleeve (8) is clearance-fitted with the piston rod (12); the second sealing ring (9) and the piston rod (12) are interference-fitted.

6. The dual-cylinder, three-chamber air-bearing shock absorber according to claim 1, characterized in that: The lower end of the piston rod (12) is coaxially fixed to the active piston (3), and its upper end is coaxially fixed to the top of the upper cylinder (1).

7. The dual-cylinder, three-chamber air-bearing shock absorber according to claim 1, characterized in that: A recoil body (10) is fitted onto the piston rod (12); the lower end of the recoil body (10) is in contact with the upper part of the lower cylinder (2).

8. The dual-cylinder, three-chamber air-bearing shock absorber according to claim 7, characterized in that: The recoil body (10) is made of polyurethane or hydrogenated nitrile butadiene.

9. The dual-cylinder, three-chamber air-bearing shock absorber according to claim 1, characterized in that, A buffer ring (11) is fitted on the piston rod (12); and the buffer ring (11) is located between the sealing guide assembly (8) and the active piston (3).

10. The dual-cylinder, three-chamber air-bearing shock absorber according to claim 1, characterized in that, The active piston (3) is equipped with a third sealing ring (13); the floating piston (4) is equipped with a fourth sealing ring (14).

Images