Self-adaptive stiffness hydro-pneumatic spring and stiffness control method

Abstract

The invention relates to a stiffness-adaptive hydro-pneumatic spring and a stiffness control method, and belongs to the technical field of hydro-pneumatic springs. The stiffness-adaptive hydro-pneumatic spring comprises a main working cylinder, a piston assembly is arranged in the main working cylinder, an inner cavity of the main working cylinder is divided into a first cavity and a second cavity by the piston assembly, and the main working cylinder is filled with an oil mist medium; at least one low-pressure gas cavity and at least one high-pressure gas cavity are formed in the auxiliary working cylinder, and the gas pressure in the low-pressure gas cavity is lower than that in the high-pressure gas cavity; the oil way assembly is configured to enable the first cavity and the second cavity to independently communicate with corresponding low-pressure air cavities in the auxiliary working cylinder. Self-adaptive adjustment of the rigidity is achieved, the self-adaptive capacity and the damping effect of the hydro-pneumatic spring are improved, and the damping requirement under the complex working condition can be effectively met.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic spring technology, and particularly relates to an adaptive stiffness hydraulic spring and a stiffness control method, which can be widely used in various mechanical devices that require shock absorption and buffering functions. Background Technology

[0002] Gas springs are special springs used in automotive suspension systems, achieving cushioning and shock absorption through the interaction of fluid and gas. However, in existing mechanical damping applications, traditional gas springs have certain limitations in performance. Specifically, some gas springs, due to their fixed stiffness, are difficult to adaptively adjust according to different operating conditions and loads, resulting in unsatisfactory damping effects in various usage scenarios; some gas springs, due to their singular damping characteristics, cannot meet the different damping performance requirements under complex operating conditions; furthermore, in the interaction between gas and liquid media, it is difficult to simultaneously consider the rapid response characteristics of gas and the good damping effect of liquid, which affects the overall performance and damping quality of the gas spring. Therefore, those skilled in the art urgently need to provide a new type of gas spring to overcome the above-mentioned shortcomings. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides an adaptive stiffness gas spring and a stiffness control method. This achieves adaptive stiffness adjustment, improving the adaptive capability and damping effect of the gas spring, effectively meeting damping requirements under complex working conditions. It solves the technical problems of limited stiffness performance and lag in damping response found in existing technologies. The adaptive stiffness gas spring of this invention can be widely applied in various mechanical devices requiring damping and buffering functions, such as vehicle suspension systems and industrial equipment vibration damping devices.

[0004] This invention provides an adaptive stiffness hydropneumatic spring, comprising: The main working cylinder is equipped with a piston assembly inside, which divides the inner cavity of the main working cylinder into a first chamber and a second chamber. The main working cylinder is filled with an oil mist medium. The auxiliary working cylinder has at least one low-pressure air chamber and at least one high-pressure air chamber inside, and the gas pressure in the low-pressure air chamber is lower than the gas pressure in the high-pressure air chamber. The oil circuit assembly is configured to independently connect the first chamber and the second chamber to the corresponding low-pressure air chambers in the auxiliary working cylinder. When the external load on the piston assembly is less than the stiffness switching threshold force, the oil mist medium interacts only with the low-pressure air chamber, and the oil-air spring exhibits the first stiffness. When the external load on the piston assembly is greater than or equal to the stiffness switching threshold force, the oil mist medium interacts with both the low-pressure air chamber and the high-pressure air chamber, and the oil-air spring switches to a second stiffness greater than the first stiffness.

[0005] The adaptive stiffness hydropneumatic spring of the present invention achieves adaptive stiffness adjustment by setting a main working cylinder, an auxiliary working cylinder and an independent oil circuit assembly connecting the main working cylinder and the auxiliary working cylinder, and using the stiffness switching threshold force as the judgment criterion.

[0006] In some embodiments, a high-pressure air chamber located in the middle and a first low-pressure air chamber and a second low-pressure air chamber located on both sides of the high-pressure air chamber are formed in the auxiliary working cylinder.

[0007] This technical solution enables the gas spring to share the same high-pressure air chamber during both the extension and compression strokes, simplifying the structure and ensuring operational stability during the switching between extension and compression stiffness.

[0008] In some embodiments, an isolation component is also included, the isolation component further comprising: The first floating piston is movably disposed between the first low-pressure air chamber and the high-pressure air chamber; The second floating piston is movably disposed between the second low-pressure air chamber and the high-pressure air chamber.

[0009] By using a floating piston to divide the auxiliary working cylinder into a low-pressure air chamber and a high-pressure air chamber, zoned pressure control within the auxiliary working cylinder is achieved.

[0010] In some embodiments, a limiting component is also included, the limiting component further comprising: Two first stops are symmetrically fixed in the auxiliary working cylinder, located on the side of the first floating piston facing away from the high-pressure air chamber. The first stops are used to limit the extreme position of the first floating piston moving towards the first low-pressure air chamber. Two second stops are symmetrically fixed inside the auxiliary working cylinder, located on the side of the second floating piston facing away from the high-pressure air chamber. The second stops are used to limit the extreme position of the second floating piston's movement toward the second low-pressure air chamber.

[0011] By setting a stop on the side of the floating piston facing away from the high-pressure air chamber, the extreme position of the floating piston moving towards the low-pressure air chamber is limited, fixing the high-pressure air chamber within a preset range and ensuring the linearity and stability of stiffness adjustment.

[0012] In some embodiments, the oil passage assembly includes: The first connecting oil circuit connects the first chamber to one of the low-pressure air chambers of the auxiliary working cylinder; The second connecting oil passage connects the second chamber to another low-pressure air chamber of the auxiliary working cylinder; The first damping valve is installed on the first connecting oil line; The second damping valve is located on the second connecting oil line.

[0013] Through the independent connection oil circuit design, the two chambers of the main working cylinder are independently connected to the low-pressure air chamber corresponding to the auxiliary working cylinder. The dual damping design controls the throttling resistance of different strokes, so that the oil flow paths of the compression stroke and the extension stroke are completely separated, avoiding mutual interference and effectively meeting the vibration reduction requirements under complex working conditions.

[0014] In some embodiments, both the first damping valve and the second damping valve are electromagnetic damping valves.

[0015] By employing an electromagnetic damping valve, the damping force can be adjusted in real time according to the control signal.

[0016] In some embodiments, a first damping valve is used to control the throttling resistance of the piston assembly during the compression stroke, and a second damping valve is used to control the throttling resistance of the piston assembly during the extension stroke, wherein the throttling resistances of the first damping valve and the second damping valve are adjusted independently of each other.

[0017] Two damping valves are used to control the throttling resistance of the piston assembly during the compression and extension strokes respectively, without interfering with each other, which can effectively meet the vibration reduction requirements under complex working conditions.

[0018] In some embodiments, the oil mist medium in the main working cylinder comes into direct contact with the low-pressure air chamber of the auxiliary working cylinder via the oil circuit assembly.

[0019] By setting the oil mist medium in the main working cylinder to directly contact the low-pressure gas chamber of the auxiliary working cylinder through the oil circuit assembly, the gas-liquid mixing characteristics of the oil mist are utilized; the gas response speed is fast, making the stiffness switching more sensitive; the characteristics of liquid oil ensure the damping effect.

[0020] In another aspect, the present invention provides a method for controlling the stiffness of a gas spring, applicable to a gas spring with adaptive stiffness, comprising a compression stroke stiffness control step: Pressure is applied to the piston assembly, and the oil mist medium in the first chamber is pressurized and flows into the first low-pressure gas chamber corresponding to the auxiliary working cylinder through the oil circuit assembly; When the applied pressure is less than the preset stiffness switching threshold force, the oil mist medium only interacts with the first low-pressure air chamber, and the oil-air spring exhibits the first stiffness. When the applied pressure is greater than or equal to the preset stiffness switching threshold force, the oil mist medium interacts with the first low-pressure air chamber and the high-pressure air chamber simultaneously, and the oil-gas spring switches to a second stiffness greater than the first stiffness.

[0021] This compression stroke stiffness control step ensures that low stiffness is maintained to filter out bumps when subjected to small impacts, and automatically increases stiffness to provide sufficient support when subjected to large impacts, thus achieving rapid switching of compression stroke stiffness.

[0022] In another aspect, the present invention provides a method for controlling the stiffness of a gas spring, applicable to a gas spring with adaptive stiffness, comprising a step for controlling the stiffness of the extension stroke: When a pulling force is applied to the piston assembly, the oil mist medium in the second chamber is pressurized and flows into the second low-pressure gas chamber corresponding to the auxiliary working cylinder through the oil circuit assembly; When the applied tension is less than the preset stiffness switching threshold force, the oil mist medium only interacts with the second low-pressure air chamber, and the oil-air spring exhibits the first stiffness. When the applied tension is greater than or equal to the preset stiffness switching threshold force, the oil mist medium interacts with the second low-pressure air chamber and the high-pressure air chamber simultaneously, and the oil-gas spring switches to a second stiffness greater than the first stiffness.

[0023] This tension stroke stiffness control step can maintain low stiffness to preserve tire contact when subjected to small tensile forces, and automatically increase stiffness to suppress excessive body roll when subjected to large tensile forces, thus achieving adaptive stiffness control of the tension stroke and improving vehicle handling safety.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: The adaptive stiffness hydropneumatic spring of the present invention achieves adaptive stiffness adjustment by setting a main working cylinder, an auxiliary working cylinder, and an independent oil circuit assembly connecting the main working cylinder and the auxiliary working cylinder, using the stiffness switching threshold force as the judgment criterion; the auxiliary working cylinder has at least one low-pressure air chamber and at least one high-pressure air chamber. Through the two-stage pressure design, the hydropneumatic spring can automatically adjust its stiffness according to changes in load and working conditions, without the need for additional control devices or complex adjustment mechanisms, thus improving the system's adaptability and vibration reduction effect; the two chambers of the main working cylinder and the corresponding low-pressure air chamber of the auxiliary working cylinder are independently connected through independent connecting oil circuits. The dual damping design controls the throttling resistance of different strokes, so that the oil flow paths of the compression stroke and the extension stroke are completely separated, avoiding mutual interference and effectively meeting the vibration reduction requirements under complex working conditions; it fully utilizes the advantages of oil mist having both the rapid response characteristics of gas and the good damping effect of hydraulic oil, improving the response speed and overall performance of the hydropneumatic spring, and overcoming the shortcomings of traditional hydropneumatic springs in terms of medium coordination. Attached Figure Description

[0025] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a schematic diagram of a structure of an embodiment of the adaptive stiffness hydropneumatic spring of the present invention; Figure 2 This is a schematic diagram of the structure of the adaptive stiffness oil-gas spring of the present invention after being filled with an oil-gas medium. Figure 3This is a schematic diagram of the structure of a common nitrogen spring; Figure 4 A comparison chart of the output force curves of a conventional nitrogen cylinder and the adaptive hydraulic spring of this invention; Figure 5 This is a comparison chart of the stiffness curves of a conventional nitrogen cylinder and the adaptive oil-gas spring of this invention.

[0026] In the diagram: 110, main working cylinder; 111, first chamber; 112, second chamber; 113, oil mist medium; 120, auxiliary working cylinder; 121, first low-pressure air chamber; 122, high-pressure air chamber; 123, second low-pressure air chamber; 131, first piston; 132, first piston rod; 141, first connecting oil passage; 142, second connecting oil passage; 143, first damping valve; 144, second damping valve; 151, first floating piston; 152, second floating piston; 161, first stop block; 162, second stop block; 210. Cylinder barrel; 220. Mounting part; 231. Second piston; 232. Second piston rod; 233. Piston rod guide bearing; 234. Orifice; 235. Sealing ring; 240. Compressed nitrogen; 250. Oil. Detailed Implementation

[0027] The technical solutions in 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 a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0028] In the description of this invention, it should be understood that the terms "center," "lateral," "longitudinal," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," and "third" may explicitly or implicitly include one or more of that feature.

[0029] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] This invention provides an adaptive stiffness hydropneumatic spring and a stiffness control method, see attached figure. Figure 1 The diagram shown is a structural schematic of an adaptive stiffness hydropneumatic spring according to an embodiment of the present invention. The adaptive stiffness hydropneumatic spring includes a main working cylinder 110, a secondary working cylinder 120, an oil circuit assembly connecting the main working cylinder 110 and the secondary working cylinder 120, an isolation assembly, and a limiting assembly. Through the coordinated design of the main working cylinder 110 and the secondary working cylinder 120, and the optimized configuration of dual damping valves and dual pressure zones, adaptive stiffness adjustment, independent dual damping adjustment, and efficient coordination of the oil mist medium 113 are achieved, effectively solving the problems of single performance, lag in damping response, and complex structure found in existing hydropneumatic springs.

[0031] refer to Figure 1 As shown in Figure 2, the main working cylinder 110 is the core component of the gas spring that bears external force, generates damping and supporting force. The main working cylinder 110 contains a first piston rod 132 and a first piston 131. The first piston 131 divides the main working cylinder 110 into a first chamber 111 without a piston rod and a second chamber 112 with a piston rod. The main working cylinder 110 is filled with an oil mist medium 113. The auxiliary working cylinder 120 contains a high-pressure air chamber 122 in the center and a first low-pressure air chamber 121 and a second low-pressure air chamber 123 on either side of the high-pressure air chamber 122. The high-pressure air chamber 122 stores high-pressure gas, while both the first low-pressure air chamber 121 and the second low-pressure air chamber 123 store low-pressure gas. This invention's gas spring has two pressure regions with different working pressures. When the load is small, the low-pressure region works first. As the load increases, the high-pressure region participates in the work. At this time, the low and high pressure regions work simultaneously, achieving adaptive adjustment of stiffness.

[0032] refer to Figure 1As shown in Figure 2, the auxiliary working cylinder 120 and the main working cylinder 110 are connected via an oil circuit assembly. The oil circuit assembly includes a first connecting oil circuit 141 for connecting the first chamber 111 and the first low-pressure air chamber 121; a first electromagnetic damping valve, located on the first connecting oil circuit 141, for controlling the throttling resistance of the first piston rod 132 during its compression stroke; a second connecting oil circuit 142 for connecting the second chamber 112 and the second low-pressure air chamber 123; a second electromagnetic damping valve, located on the second connecting oil circuit 142, for controlling the throttling resistance of the first piston rod 132 during its extension stroke; and an oil mist medium in the main working cylinder 110. The oil mist medium 113 is directly in contact with the first low-pressure air chamber 121 of the auxiliary working cylinder 120 via the first connecting oil passage 141 and the first electromagnetic damping valve. The oil mist medium 113 in the main working cylinder 110 is directly in contact with the second low-pressure air chamber 123 of the auxiliary working cylinder 120 via the second connecting oil passage 142 and the second electromagnetic damping valve. By setting the above-mentioned oil passage components, the oil flow path is completely separated during the compression and extension of the first piston rod 132. The first electromagnetic damping valve and the second electromagnetic damping valve control the throttling resistance at different strokes, thereby realizing the pressure transmission and stiffness adjustment of the gas and oil mist medium 113.

[0033] refer to Figure 1 As shown in Figure 2, the isolation assembly of the adaptive stiffness hydropneumatic spring of the present invention includes a first floating piston 151, movably disposed between a first low-pressure air chamber 121 and a high-pressure air chamber 122; and a second floating piston 152, movably disposed between a second low-pressure air chamber 123 and a high-pressure air chamber 122. The first floating piston 151 and the second floating piston 152 divide the auxiliary working cylinder 120 into at least one low-pressure air chamber and at least one high-pressure air chamber 122.

[0034] To maintain the stability of the high-pressure gas compression space, this invention provides a limiting component outside the high-pressure gas chamber 122 to restrict the boundary of the high-pressure gas region and ensure that the position of the high-pressure gas chamber 122 is fixed. (Reference) Figure 1 As shown in Figure 2, the limiting assembly includes two first stops 161, symmetrically fixedly disposed within the auxiliary working cylinder 120, located on the side of the first floating piston 151 facing away from the high-pressure gas chamber 122. The first stops 161 are used to limit the extreme position of the first floating piston 151 moving towards the first low-pressure gas chamber 121. Two second stops 162, symmetrically fixedly disposed within the auxiliary working cylinder 120, located on the side of the second floating piston 152 facing away from the high-pressure gas chamber 122. The second stops 162 are used to limit the extreme position of the second floating piston 152 moving towards the second low-pressure gas chamber 123. The auxiliary working cylinder 120 is designed with a three-section structure: low-pressure zone, high-pressure zone, and low-pressure zone. Together with the floating first piston 131 and the stops, it constructs a high-pressure gas chamber 122 with a fixed position, storing high-pressure gas, ensuring the linearity and stability of stiffness adjustment.

[0035] The stiffness control method of the oil-gas spring of the present invention includes a compression stroke stiffness control step and a tension stroke stiffness control step. Among them, the compression stroke stiffness control step includes: applying a pressure F to the first piston rod 132 压 , the first piston 131 moves towards the first chamber 111, the volume of the first chamber 111 decreases, the oil mist medium 113 in the first chamber 111 is compressed, and flows into the first chamber 111 of the auxiliary working cylinder 120 through the first electromagnetic damping valve: when F 压 <F (F is the stiffness switching threshold force, set according to the target performance), the oil mist medium 113 only compresses the first low-pressure gas chamber 121 in the auxiliary working cylinder 120, and the oil-gas spring exhibits the first low-pressure stiffness K3; when F 压 ≥F, the oil mist medium 113 simultaneously compresses the first low-pressure gas chamber 121 and the high-pressure gas chamber 122 in the auxiliary working cylinder 120, and the oil-gas spring switches to the second high-pressure stiffness K4, and K4>K3, realizing stiffness improvement.

[0036] The tension stroke stiffness control step includes: applying a tensile force F to the first piston rod 132 拉 , the first piston 131 moves towards the second chamber 112, the volume of the second chamber 112 decreases, the oil mist medium 113 in the second chamber 112 is compressed, and flows into the second low-pressure gas chamber 123 of the auxiliary working cylinder 120 through the second electromagnetic damping valve from the second communication oil path 142: when F 拉 <F (F is the stiffness switching threshold force, set according to the target performance), the oil mist medium 113 only compresses the second low-pressure gas chamber 123 in the auxiliary working cylinder 120, and the oil-gas spring exhibits the first low-pressure stiffness K1; when F 拉 ≥F, the oil mist medium 113 simultaneously compresses the second low-pressure gas chamber 123 and the high-pressure gas chamber 122 in the auxiliary working cylinder 120, and the oil-gas spring switches to the first high-pressure stiffness K2, and K2>K1, realizing stiffness improvement.

[0037] The working principle of the oil-gas spring with adaptive stiffness of the present invention is: (1) Variable stiffness working principle Represent the second chamber 112 as chamber A, the first chamber 111 as chamber B, the first low-pressure gas chamber 121 as chamber C, the second low-pressure gas chamber 123 as chamber D, and the high-pressure gas chamber 122 as chamber E.

[0038] The oil-gas spring utilizes the compressible characteristics of oil mist and gas volume to realize the function of an elastic element, and follows the state equation of a perfect gas: PV = RT Where, P is the absolute pressure of the gas, V is the mass volume of the gas, R is the gas constant, and T is the gas temperature.

[0039] Since chamber A and chamber D of the oil-gas spring are connected, so P A =P DCavity B is connected to cavity C, therefore P B =P D When the pressure F1 applied to the first piston rod 132 is less than F, chamber E does not work, i.e., it is not compressed, then V EA0 =V EB0 =V E0 / 2, Taking the extension stroke as an example, according to the gas state equation, assuming the gas compression process is adiabatic, the gas compression of the adaptive oil-gas spring conforms to an adiabatic process:

[0040]

[0041] Among them, P A0 V is the initial pressure of the second chamber 112. A0 V is the initial volume of the second chamber 112. EA0 For the initial volume of the second chamber 112 of the auxiliary working cylinder 120, P A For the pressure in the second chamber 112, V A The volume of the second chamber is 112, P. B0 V is the initial pressure in the first chamber 111. B0 V is the initial volume of the first chamber 111. EB0 For the initial volume of the first chamber 111 of the auxiliary working cylinder 120, P B For the pressure in the first chamber 111, V B The first chamber has a volume of 111, where γ is the gas adiabatic index, which is generally taken as 1.4 for adiabatic processes, and C is a constant.

[0042] When the first piston 131 of the main working cylinder 110 has a stroke of x:

[0043]

[0044] Neglecting the effect of damping, using the ideal gas law, the output force of the first piston 131 during the stretching stroke can be obtained as follows:

[0045] Differentiating the above equation, we can obtain the stiffness K for this stage:

[0046] When F1 ≥ F, cavity E begins to work, and the stroke of auxiliary working cylinder 120 is... ,but:

[0047]

[0048] in, The volume of the second chamber 112 of the auxiliary working cylinder 120 is... The volume of the first chamber 111 of the auxiliary working cylinder 120.

[0049] Assume the extension stroke of the first piston 131 in the main working cylinder 110 is x, and the stroke of the auxiliary working cylinder 120 is... :

[0050] When the high-pressure air chamber 122 is engaged, the output force of the first piston 131 during the stretching stroke is:

[0051] Differentiating the above equation, we can obtain the stiffness at this stage:

[0052] As can be seen from the above formula derivation process, the output force of the gas spring is related to the stroke of the first piston 131. When the stroke of the first piston 131 is greater than the stroke corresponding to the set pressure value, the high-pressure air chamber 122 of the gas spring starts to work.

[0053] Mathematical model verification refer to Figure 3 The diagram shows the structure of a common nitrogen spring. The working principle of the nitrogen cylinder is as follows: high-pressure nitrogen is filled into the sealed cylinder. Due to the different cross-sectional areas on both sides of the second piston 231 (the area on one side of the second piston rod 231 is smaller), a pressure difference is generated, which pushes the second piston rod 231 to move outward and provides continuous elastic force. When compressed by external force, the nitrogen is further compressed and stores energy. After the external force is removed, the gas expands and returns to its original position.

[0054] By setting the same parameters, the output force curves and stiffness curves of the adaptive stiffness hydropneumatic spring and the ordinary nitrogen spring were compared. The results are shown in the attached figures. Figure 4 and 5 As shown in the figure above, the stiffness of a conventional nitrogen cylinder increases with the stroke of the second piston 231, and the larger the stroke of the second piston 231, the higher the rate of stiffness change. This makes the stiffness of the nitrogen spring increase faster when subjected to heavy loads. In contrast, the stiffness of the adaptive stiffness hydropneumatic spring decreases after a certain stroke of the first piston 131 compared to the conventional nitrogen cylinder, and the rate of stiffness change is smaller, making it suitable for applications requiring comfort.

[0055] (2) Working principle of dual damping The core of the dual-damping working principle of the gas spring lies in setting up two sets of independently connected oil circuit damping channels to achieve differentiated vibration reduction adjustment for the compression and extension strokes. The design of the bidirectional independent damping channels involves installing damping valves on the connecting oil lines between the main working cylinder 110 and the auxiliary working cylinder 120, completely separating the oil flow paths during compression and extension, and controlling the throttling resistance at different strokes. Utilizing the oil mist elastic medium characteristics of the gas spring, combined with the dual damping channels, a coordinated change in stiffness and damping is achieved.

[0056] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

Claims

1. A hydropneumatic spring with adaptive stiffness, characterized in that, include The main working cylinder is equipped with a piston assembly inside, which divides the inner cavity of the main working cylinder into a first chamber and a second chamber. The main working cylinder is filled with an oil mist medium. The auxiliary working cylinder has at least one low-pressure air chamber and at least one high-pressure air chamber inside, and the gas pressure in the low-pressure air chamber is lower than the gas pressure in the high-pressure air chamber. The oil circuit assembly is configured to independently connect the first chamber and the second chamber to the corresponding low-pressure air chambers in the auxiliary working cylinder; when the external load on the piston assembly is less than the stiffness switching threshold force, the oil mist medium interacts only with the low-pressure air chamber, and the oil-gas spring exhibits a first stiffness; when the external load on the piston assembly is greater than or equal to the stiffness switching threshold force, the oil mist medium interacts with both the low-pressure air chamber and the high-pressure air chamber, and the oil-gas spring switches to a second stiffness greater than the first stiffness.

2. The adaptive stiffness gas spring according to claim 1, characterized in that, The auxiliary working cylinder has a high-pressure air chamber in the middle and a first low-pressure air chamber and a second low-pressure air chamber on both sides of the high-pressure air chamber.

3. The adaptive stiffness hydropneumatic spring according to claim 2, characterized in that, It also includes an isolation component, the isolation component further including A first floating piston is movably disposed between the first low-pressure air chamber and the high-pressure air chamber; The second floating piston is movably disposed between the second low-pressure air chamber and the high-pressure air chamber.

4. The adaptive stiffness hydropneumatic spring according to claim 3, characterized in that, It also includes a limiting component, the limiting component further including Two first stop blocks are symmetrically fixedly disposed in the auxiliary working cylinder, located on the side of the first floating piston facing away from the high-pressure air chamber. The first stop blocks are used to limit the extreme position of the first floating piston moving towards the first low-pressure air chamber. Two second stop blocks are symmetrically fixedly disposed inside the auxiliary working cylinder, located on the side of the second floating piston facing away from the high-pressure air chamber. The second stop blocks are used to limit the extreme position of the movement of the second floating piston towards the second low-pressure air chamber.

5. The adaptive stiffness hydropneumatic spring according to claim 1, characterized in that, The oil circuit assembly includes: The first connecting oil circuit connects the first chamber to one of the low-pressure air chambers of the auxiliary working cylinder; The second connecting oil passage connects the second chamber to another low-pressure air chamber of the auxiliary working cylinder; A first damping valve is installed on the first connecting oil line; The second damping valve is located on the second connecting oil line.

6. The adaptive stiffness hydropneumatic spring according to claim 5, characterized in that, Both the first damping valve and the second damping valve are electromagnetic damping valves.

7. The adaptive stiffness hydropneumatic spring according to claim 5, characterized in that, The first damping valve is used to control the throttling resistance of the piston assembly during the compression stroke, and the second damping valve is used to control the throttling resistance of the piston assembly during the extension stroke. The throttling resistances of the first damping valve and the second damping valve are adjusted independently of each other.

8. The adaptive stiffness gas spring according to claim 1, characterized in that, The oil mist medium in the main working cylinder comes into direct contact with the low-pressure air chamber of the auxiliary working cylinder via the oil circuit assembly.

9. A method for controlling the stiffness of a gas spring, applied to a gas spring with adaptive stiffness as described in any one of claims 2 to 8, characterized in that, Including compression stroke stiffness control steps: Pressure is applied to the piston assembly, and the oil mist medium in the first chamber is pressurized and flows into the first low-pressure gas chamber corresponding to the auxiliary working cylinder through the oil circuit assembly; When the applied pressure is less than the preset stiffness switching threshold force, the oil mist medium interacts only with the first low-pressure air chamber, and the oil-air spring exhibits the first stiffness. When the applied pressure is greater than or equal to the preset stiffness switching threshold force, the oil mist medium interacts with the first low-pressure air chamber and the high-pressure air chamber simultaneously, and the oil-gas spring switches to a second stiffness greater than the first stiffness.

10. A method for controlling the stiffness of a gas spring, applied to a gas spring with adaptive stiffness as described in any one of claims 2 to 8, characterized in that, Including the steps for controlling the stiffness of the tension stroke: When a pulling force is applied to the piston assembly, the oil mist medium in the second chamber is pressurized and flows into the second low-pressure gas chamber corresponding to the auxiliary working cylinder through the oil circuit assembly; When the applied tension is less than the preset stiffness switching threshold force, the oil mist medium interacts only with the second low-pressure air chamber, and the oil-air spring exhibits the first stiffness. When the applied tension is greater than or equal to the preset stiffness switching threshold force, the oil mist medium interacts with the second low-pressure air chamber and the high-pressure air chamber simultaneously, and the oil-gas spring switches to a second stiffness greater than the first stiffness.

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