Piston sealing structure and energy accumulator applying same

Abstract

The invention discloses a piston sealing structure which is arranged in an energy accumulator outer cylinder and comprises an energy accumulator piston arranged in the energy accumulator outer cylinder in a sliding mode, and a plurality of annular grooves are sequentially formed in the outer circumferential wall of the energy accumulator piston in the axial direction. A supporting ring, a step seal, a main sealing assembly and a step seal are sequentially arranged on the multiple annular grooves from the air cavity side to the liquid cavity side, the supporting ring and the step seal serve as auxiliary sealing assemblies and comprise O-shaped rings and V-shaped step seal sealing rings arranged outside the O-shaped rings in a sleeving mode, and pressure relief holes are formed in the V-shaped step seal sealing rings in the circumferential direction. A pressure relief groove is formed in the side, away from the main sealing assembly, of the V-shaped step seal sealing ring. According to the step seal, the pressure relief groove and the pressure relief hole are designed for the sealing ring of the V-shaped step seal, automatic release of built-up pressure can be achieved, the problem of built-up pressure among multiple sealing structures such as the main sealing assembly and the auxiliary sealing assembly is solved, starting friction force of the energy accumulator piston is reduced, and the service life of the piston sealing structure is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic transmission, in particular to a piston sealing structure and an accumulator using the same. BACKGROUND

[0002] The piston accumulator is a common hydraulic accessory in the hydraulic system, which is an energy conversion device mainly used for storing energy, absorbing pulsating pressure and absorbing hydraulic impact in the hydraulic system. The piston accumulator separates gas and liquid by using a piston, and there is a seal between the piston and the inner wall of the accumulator outer cylinder.

[0003] At present, for the working condition of the accumulator piston requiring to realize gas-liquid isolation, a sealing structure using rubber seal + rubber seal, rubber seal + combined seal in series is commonly used, but such sealing structure has the phenomenon of pressure accumulation between multiple series seals, which can cause the increase of piston starting friction and the reduction of service life of the sealing element. SUMMARY

[0004] The present application provides a piston sealing structure and an accumulator using the same, which can solve the problem of pressure accumulation between multiple series seals in the prior art, thereby causing the increase of piston starting friction and the reduction of service life of the sealing element.

[0005] A piston sealing structure is arranged in an accumulator outer cylinder, the piston sealing structure comprising an accumulator piston slidably arranged in the accumulator outer cylinder, a plurality of annular grooves are sequentially arranged on the outer circumferential wall of the accumulator piston in the axial direction, and a support ring, a stellite seal, a main sealing assembly, a stellite seal and a support ring are sequentially arranged from the gas cavity side to the liquid cavity side. The stellite seal as an auxiliary sealing assembly comprises an O-ring and a V-shaped stellite seal ring sleeved outside the O-ring, the V-shaped stellite seal ring is circumferentially provided with a pressure relief hole, and the V-shaped stellite seal ring is provided with a pressure relief groove on the side away from the main sealing assembly, the O-ring moves under the action of pressure, and the stellite seal has two states. In the first state, the O-ring is close to the main sealing assembly, and the pressure relief hole is blocked. In the second state, the O-ring is away from the main sealing assembly, and the medium flows to the pressure relief groove through the pressure relief hole.

[0006] The piston sealing structure provided by the present application has the following beneficial effects compared with the prior art, but is not limited to the following: The piston sealing structure, under the pressure build-up working condition, the accumulator piston is guided by the support ring and moves in the accumulator outer cylinder, the high-pressure fluid medium generated by the pressure build-up first acts on the O-ring sealed in the annular groove, at this time the O-ring seal presents the second state, the fluid medium pushes the O-ring away from the main sealing assembly, after the displacement of the O-ring, the pressure relief hole originally blocked is released, the pressure build-up fluid flows to the pressure relief groove through the pressure relief hole, the pressure relief groove is directly communicated with the low-pressure area, and the pressure build-up fluid is discharged to the low-pressure area, and the pressure relief is completed, after the pressure relief is completed, the working condition returns to normal, and the O-ring seal presents the first state, and the O-ring is close to the main sealing assembly and blocks the pressure relief hole.

[0007] The O-ring seal can realize automatic release of the pressure build-up by designing the pressure relief groove and the pressure relief hole in the V-shaped O-ring seal ring, solve the pressure build-up problem between the main sealing assembly and the auxiliary sealing assembly, reduce the starting friction of the accumulator piston, and prolong the service life of the piston sealing structure.

[0008] Further, the O-ring seal as the auxiliary sealing assembly can form double sealing protection in combination with the main sealing assembly, effectively improve the gas-liquid isolation effect and the sealing life.

[0009] Further, a V-shaped groove is formed in the inner wall of the V-shaped O-ring seal ring, and a guide groove is formed in the outer wall, and the V-shaped groove and the guide groove are communicated by the pressure relief hole.

[0010] Further, the outer diameters of the edges of the two sides of the guide groove are different, the edge of the guide groove close to the main sealing assembly is in abutment with the inner wall of the accumulator outer cylinder, and the edge of the guide groove away from the main sealing assembly is not in contact with the inner wall of the accumulator outer cylinder.

[0011] Further, the main sealing assembly comprises a T-shaped ring and a protection ring, the protection ring is symmetrically arranged on the two sides of the T-shaped ring, and the protection ring is made of polytetrafluoroethylene material.

[0012] Further, the T-shaped ring is in interference fit with the accumulator outer cylinder.

[0013] Further, a buffer gap is arranged between the O-ring seal and the support ring in the same side direction of the main sealing assembly.

[0014] Further, the O-ring is made of hydrogenated nitrile rubber material, and the V-shaped O-ring seal ring is made of polyether ether ketone and carbon fiber composite material.

[0015] Further, the cross section of the T-shaped ring is in a stepped shape, an arc-shaped protrusion is arranged on the sealing surface of the T-shaped ring in contact with the inner wall of the accumulator outer cylinder, and the radius of the arc-shaped protrusion is R0.5mm-R1.2mm.

[0016] Further, grease storage ring grooves are formed on both sides of the annular groove where the T-shaped ring is located on the outer wall of the accumulator piston, the grease storage ring grooves are in communication with the annular groove, and the grease storage ring grooves are filled with grease.

[0017] An accumulator comprises an accumulator outer cylinder, and the accumulator outer cylinder is provided with the piston sealing structure as described above.

[0018] Since the accumulator has the technical improvements and advantages at least as the piston sealing structure, the accumulator will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A structural schematic diagram of a sealing structure in the prior art in which rubber sealing and rubber sealing are used in series; Figure 2 A sealing structure in which rubber sealing and combined sealing are used in series in the prior art; Figure 3 A sectional view of the piston sealing structure of one embodiment of the present application; Figure 4 A sectional view of the V-shaped Stellite sealing ring on the right side in the middle; Figure 3 A sectional view of the V-shaped Stellite sealing ring on the left side in the middle; Figure 5 Figure 3 A sectional view of the V-shaped Stellite sealing ring on the left side in the middle; Figure 6 A structural schematic diagram of the grease storage ring grooves provided on both sides of the T-shaped ring in one embodiment.

[0020] REFERENCE SIGNS: 1, accumulator outer cylinder; 2, accumulator piston; 3, support ring; 4, V-shaped Stellite sealing ring; 41, pressure relief hole; 42, pressure relief groove; 43, V-shaped groove; 44, guide groove; 5, O-shaped ring; 6, T-shaped ring; 7, protective ring. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings which show the embodiments according to the present application. It should be understood that the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments described in the present application, all other embodiments obtained by those skilled in the art without creative labor shall fall within the scope of protection of the present application.

[0022] ​Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the specification herein is for describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise defined, all terms used in disclosing the application, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms used in the description of the present application are used for illustrative purposes only and are not intended to limit the scope of the application. The terms "comprise", "comprising", "include", "including", "have" and "having" are used in the specification to mean "including but not limited to". The terms "comprise", "comprising", "include", "including", "have" and "having" are used in the specification to mean "including but not limited to". The terms "first", "second", and the like, as used in the description of the application, do not connote any order, quantity, or importance, but rather are used to distinguish one element from another. In addition, the terms "first" and "second" are used only for descriptive purposes and do not connote or imply any relative importance or any fixed number of the indicated elements. Thus, a feature defined with "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the application, the meaning of "a plurality" is two or more, unless otherwise specified.

[0023] In the description of the application, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0024] In the description of the application, it should be noted that unless otherwise specified and limited, the terms "mounting", "connecting", "connecting", "attaching" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium; it can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0025] It should be emphasized that when the term "comprise / contain" is used in the specification, it is used to explicitly indicate the presence of the features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps, components or groups of features, integers, steps, components.

[0026] The term "and / or" in the present application is only used to describe the relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in the present application generally represents an "or" relationship between the front and rear associated objects.

[0027] Referring to Figure 1 As shown, the existing accumulator piston sealing structure is generally a pure rubber sealing structure, that is, two rubber sealing rings are connected in series for sealing. Since the sealing material in contact with the dynamic sealing surface is rubber, the friction coefficient of rubber is relatively large, it is easy to wear and twist during movement, and even pressure build-up occurs, affecting the service life and sealing effect.

[0028] Referring to Figure 2 As shown, in order to improve the function of the two series rubber seals, the accumulator piston sealing structure adopts a rubber seal and a combined seal series structure, that is, the rubber seal is used to seal the high-pressure gas, and the combined seal is used to seal the oil, thereby isolating the oil impact. The combined seal refers to an integrated sealing structure formed by two or more different types and functions of sealing elements (such as elastomers, wear-resistant materials, and support elements). Its core is to consider the multiple requirements of sealing reliability, wear resistance, and impact resistance through the synergistic effect of each component, which is more suitable for complex working conditions (such as high pressure and oil impact environment) than single rubber sealing. The combined seal usually combines elastic elements and wear-resistant elements, and the common combination form is O-ring + polytetrafluoroethylene sliding ring, rubber ring + metal support ring. It is designed specifically for higher pressure oil sealing and impact resistance in hydraulic systems. Compared with pure rubber sealing, it has better wear resistance, extrusion resistance, and pressure impact resistance, and can better isolate the damage of oil impact to the sealing system.

[0029] Although the ordinary combined sealing structure can improve the sealing and wear resistance, it still cannot solve the problem of leakage failure caused by the ultra-low temperature working condition of the rubber sealing element in the gas cavity under the low temperature pressure relief of the accumulator, and it also cannot completely solve the problem of pressure build-up between multiple seals due to long-term work.

[0030] It should be noted that the pressure build-up in the art refers to the accumulation of fluid (gas or liquid) between the multiple series sealing structures connected by the accumulator piston (i.e., the gap area between different sealing elements and sealing elements, and sealing elements and piston groove walls), which causes abnormal pressure in the gap area.

[0031] The inventors found in the course of years of research that the specific scenarios and causes of pressure retention in the field can be summarized into three aspects: the closedness of the sealing structure leads to, fluid intrusion and retention, and pressure accumulation. The closedness of the sealing structure leads to: in the prior art (such as pure rubber sealing, rubber + combined sealing series structure), multiple sealing elements are arranged in sequence and are independent of each other, and a small closed gap is formed between the sealing element and the inner wall of the accumulator outer cylinder or the piston groove. Fluid intrusion and retention: during the operation of the accumulator (such as piston reciprocation, pressure fluctuation, temperature change), a small amount of gas or liquid intrudes into the above-mentioned closed area through the small gap of the sealing element and cannot be discharged through an effective path. Pressure accumulation: the intruded fluid gradually accumulates in the closed gap, and with repeated work of the accumulator (such as pressure impact, piston start-stop), the fluid in the gap is continuously squeezed, and eventually forms an abnormal pressure higher than the normal working pressure of the system, i.e. pressure retention. Pressure retention will directly lead to two major problems, i.e. increasing the piston starting friction and shortening the service life of the sealing element. The abnormal pressure generated by pressure retention will act on the sealing element, causing the contact pressure between the sealing element and the inner wall of the accumulator outer cylinder or the piston groove to abnormally increase, resulting in the need to overcome greater frictional resistance when the piston starts. Abnormal pressure will also cause the sealing element to deform and twist (especially rubber sealing elements), accelerate the wear and aging of the sealing element, and even directly damage the structural integrity of the sealing element, eventually leading to sealing failure and accumulator leakage.

[0032] Referring to Figures 3-6 As shown in the drawings, the piston sealing structure provided by the embodiment of the application is arranged in an accumulator outer cylinder 1. The piston sealing structure comprises an accumulator piston 2 slidably arranged in the accumulator outer cylinder 1, and a plurality of annular grooves are sequentially arranged on the outer circumferential wall of the accumulator piston 2 in the axial direction. The plurality of annular grooves are sequentially provided with a support ring 3, a stellite seal, a main sealing assembly, a stellite seal and a support ring 3 from the gas cavity side to the liquid cavity side.

[0033] The stellite seal as an auxiliary sealing assembly comprises an O-shaped ring 5 and a V-shaped stellite seal ring 4 sleeved outside the O-shaped ring 5. The V-shaped stellite seal ring 4 is circumferentially provided with a pressure relief hole 41, and the side of the V-shaped stellite seal ring 4 away from the main sealing assembly is provided with a pressure relief groove 42. The O-shaped ring 5 moves under the action of pressure, so that the stellite seal presents two states.

[0034] In the first state, the O-shaped ring 5 is close to the main sealing assembly and blocks the pressure relief hole 41.

[0035] In the second state, the O-shaped ring 5 is away from the main sealing assembly, so that the medium flows to the pressure relief groove 42 through the pressure relief hole 41.

[0036] The cavities on both sides of the accumulator piston 2 are a gas cavity and a liquid cavity, respectively.

[0037] In this embodiment, the pressure build-up condition is an abnormal state caused by poor pressure discharge of the piston sealing structure, which can be triggered when the accumulator piston 2 moves frequently, or indirectly caused by pressure fluctuation and temperature change when the accumulator piston 2 is stationary. Under the pressure build-up condition, the accumulator piston 2 is guided by the support ring 3 and moves in the accumulator outer cylinder 1. The high-pressure fluid medium (gas / liquid) generated by the pressure build-up first acts on the O-ring 5 sealed in the annular groove. At this time, the O-ring 5 presents the second state, and the fluid medium pushes the O-ring 5 away from the main sealing assembly. After the displacement of the O-ring 5, the originally blocked pressure relief hole 41 is released, and the pressure build-up fluid flows through the pressure relief hole 41 to the pressure relief groove 42, which is directly connected to the low-pressure area (gas cavity or liquid cavity). The pressure build-up fluid is discharged to the low-pressure area to complete the pressure relief. After the pressure relief is completed, the working condition returns to normal, and the O-ring 5 presents the first state, approaching the main sealing assembly and blocking the pressure relief hole 41.

[0038] The O-ring 5 can achieve automatic release of pressure build-up by designing the pressure relief groove 42 and the pressure relief hole 41 of the V-shaped O-ring 4, solving the pressure build-up problem between the main sealing assembly and the auxiliary sealing assembly, reducing the starting friction of the accumulator piston 2, and prolonging the service life of the piston sealing structure. Moreover, the O-ring 5 on the gas cavity side undertakes the temperature isolation function, avoiding the direct effect of ultra-low temperature on the main sealing assembly, so that the main sealing assembly can work stably under the ultra-low temperature condition of-60℃.

[0039] Further, the O-ring 5 as the auxiliary sealing assembly can form double sealing protection with the main sealing assembly, effectively improving the gas-liquid isolation effect and the sealing life.

[0040] It should be noted that, in normal working conditions, the expected normal operating state is designed for the accumulator, the accumulator piston 2 can normally reciprocate or be stationary, and there is no abnormal pressure accumulation in the annular groove of the accumulator piston 2. When the accumulator piston 2 is in a stationary condition, the accumulator completes energy storage, the system pressure is stable, and the accumulator piston 2 remains stationary. At this time, the main sealing assembly plays a core role in gas-liquid separation, and the Stoff seal acts as an auxiliary seal and maintains sealing under the action of pre-tightening force. There is no fluid intrusion between the seals, and there is no pressure accumulation. When the accumulator piston 2 is in a moving condition (i.e., the accumulator energy storage / energy release stage), the system pressure changes, and the accumulator piston 2 reciprocates along the accumulator outer cylinder 1 (when the accumulator piston 2 is driven by hydraulic pressure to compress the gas cavity during energy storage, and the gas cavity pressure drives the piston to discharge liquid during energy release). At this time, the Stoff seal is in a first state under the action of the positive pressure (the working pressure of the high-pressure side cavity), and the positive pressure drives the O-ring 5 to move towards the main sealing assembly, blocking the pressure relief hole 41. The O-ring 5 extrudes the V-shaped Stoff seal ring by compression deformation, making it tightly adhere to the inner wall of the accumulator outer cylinder 1, and strengthening the sealing effect to resist the pressure impact during the movement of the accumulator piston 2. Even if some fluid intrudes between the seals, it will be naturally carried out with the movement of the accumulator piston 2 and will not form pressure accumulation. The overall piston sealing structure is in a pressure balanced state.

[0041] Wherein, under the action of positive pressure, the O-ring 5 of the Stoff seal can quickly block the pressure relief hole. Not only can it achieve reliable sealing through compression deformation and pressure cooperation, but also can effectively resist the pressure impact under the working condition of ultra-high pressure of 31.5MPa-70MPa, taking into account the use environment of ultra-low temperature and ultra-high pressure.

[0042] Optionally, referring to Figures 4-5 As shown, the inner wall of the V-shaped Stoff seal ring 4 is provided with a V-shaped groove 43, and the outer wall is provided with a guide groove 44. The V-shaped groove 43 and the guide groove 44 are communicatively arranged through the pressure relief hole 41.

[0043] In this embodiment, the V-shaped cross section of the V-shaped groove 43 is directly related to the sealing principle. When the positive pressure acts, the V-shaped Stoff seal ring 4 will be stretched and expanded at the V-shaped groove 43 under the action of pressure, further tightly adhering to the inner wall of the accumulator outer cylinder 1 and the annular groove wall of the accumulator piston 1, and strengthening the sealing effect. Moreover, the V-shaped groove 43 can guide the pressure relief direction of the pressure accumulation fluid while ensuring the sealing performance of the V-shaped Stoff seal ring 4, introducing the pressure accumulation fluid into the pressure relief hole 41, and then flowing into the pressure relief groove 42 through the guide groove 44.

[0044] Optionally, referring to Figures 4-5 As shown, the outer diameters of the two side edges of the slot of the guide groove 44 are different. The slot edge close to the main sealing assembly abuts against the inner wall of the accumulator outer cylinder 1, and the slot edge away from the main sealing assembly is not in contact with the inner wall of the accumulator outer cylinder 1.

[0045] In this embodiment, the groove edge of the guide groove 44 away from the main sealing assembly has a smaller outer diameter than the other edge, so that the guide groove 44 close to the edge of the main sealing assembly has a sealing effect, and the guide groove 44 away from the edge of the main sealing assembly does not contact the accumulator outer cylinder 1, so that the medium flowing out of the pressure relief hole 41 can smoothly flow into the pressure relief groove 42 through the guide groove 44.

[0046] But in some extreme cases, such as the V-shaped Stener sealing ring 4 is deformed too much by stretching, so that the edges of the guide groove 44 on both sides of the notch fit the accumulator outer cylinder 1, the guide function of the guide groove 44 is blocked, so in some embodiments, a through hole is also provided between the guide groove 44 and the pressure relief groove 42 as a flow guide channel, further guaranteeing the guide function of the guide groove 44.

[0047] Optionally, the main sealing assembly includes a T-shaped ring 6 and a protective ring 7, the protective ring 7 is symmetrically arranged on both sides of the T-shaped ring 6, and the protective ring 7 is made of polytetrafluoroethylene material.

[0048] In this embodiment, the T-shaped ring 6 serves as the main sealing structure and undertakes the core function of gas-liquid isolation, and the protective rings 7 on both sides can effectively prevent the T-shaped ring 6 from twisting and deforming during movement, while reducing the direct friction between the T-shaped ring 6 and the Stener, thereby prolonging the service life of the main sealing assembly.

[0049] Optionally, the T-shaped ring 6 is in interference fit with the accumulator outer cylinder 1.

[0050] In this embodiment, through the interference fit between the T-shaped ring 6 and the accumulator outer cylinder 1, the T-shaped ring 6 can be closely attached to the accumulator outer cylinder 1 under different pressures and deformations, rather than relying solely on deformation to ensure sealing, thereby effectively improving the sealing performance of the main sealing assembly.

[0051] Optionally, in some embodiments, a buffer gap is provided between the Stener and the support ring 3 on the same side of the main sealing assembly, and the width of the buffer gap is 0.3mm-0.8mm. The buffer gap can reduce assembly stress and movement interference.

[0052] Specifically, the buffer gap provides redundant space for assembly error compensation, thermal expansion and contraction deformation buffering, and motion posture self-adaptation of the sealing structure, reduces stress accumulation and interference risk from the root by eliminating forced extrusion between components, and adapting to dynamic changes. There are inevitable errors in the process of machining and assembly, and the buffer gap effectively alleviates the extrusion stress caused by these errors by reserving redundancy. The buffer gap is equivalent to an error absorption zone, so that each component does not need to bear forced extrusion after assembly and maintains a natural fit state, thereby minimizing assembly stress. When the accumulator is working, the accumulator piston 2 will do reciprocating motion, and the changes of system temperature and pressure will cause the components to deform. The buffer gap avoids the motion interference between the components through dynamic adaptation. In this application, the material thermal expansion coefficients of the accumulator piston 2, the support ring 3, the stellite seal and the main seal assembly are different in the extreme working conditions from ultra-low temperature (-60℃) to normal temperature (80℃). The components shrink at low temperature and expand at high temperature. The axial expansion of the components at high temperature will cause the support ring 3 and the stellite seal to push each other, generate thermal stress, and at the same time limit the reciprocating motion stroke of the accumulator piston 2. Although the shrinkage of the components at low temperature will not cause extrusion, it is easy to cause the seal to not fit tightly. The existence of the buffer gap allows each component to freely stretch and contract, avoiding motion jam caused by deformation. When the accumulator piston 2 reciprocates, it will also have a slight tilt due to the guiding precision (such as axial movement and radial swing). The buffer gap can accommodate such small attitude changes. If the buffer gap is not set, the support ring 3 and the stellite seal will have different degrees of edge friction due to the tilt of the accumulator piston 2, that is, motion interference, which is manifested as increased friction resistance and aggravated component wear. In the ultra-high pressure working condition (31.5MPa-70MPa), the pressure impact of the accumulator piston 2 in motion will cause the stellite seal to have a slight axial deformation (such as the opening of the V-shaped stellite seal ring 4 and the compression of the O-ring 5), and the buffer gap can provide space for such deformation to avoid extrusion interference between the deformed stellite seal and the support ring 3, and ensure the stable motion posture of the seal.

[0053] Optionally, the O-ring 5 is made of hydrogenated nitrile rubber material, and the V-shaped stellite seal ring 4 is made of polyether ether ketone and carbon fiber composite material. The use of these two materials can effectively improve the adaptability of extreme working conditions.

[0054] Optionally, the cross section of the T-shaped ring 6 is in a stepped shape, the sealing surface of the T-shaped ring 6 in contact with the inner wall of the accumulator outer cylinder 1 is provided with an arc-shaped protrusion, and the radius of the arc-shaped protrusion is R0.5mm-R1.2mm. The arc-shaped protrusion optimizes the sealing surface structure of the T-shaped ring 6, improves the sealing contact effect, improves the sealing reliability, and at the same time reduces the friction resistance between the T-shaped ring 6 and the accumulator outer cylinder 1.

[0055] Optionally, referring to Figure 6As shown, in some embodiments, grease storage ring grooves are formed on both sides of the annular groove where the T-shaped ring 6 is located on the outer wall of the accumulator piston 2, the grease storage ring grooves are in communication with the annular groove, and the grease storage ring grooves are filled with low-temperature wear-resistant grease.

[0056] In this embodiment, the grease can form a stable oil film on the sealing surface, reduce the kinetic friction, and at the same time improve the low-temperature adaptability of the T-shaped ring 6.

[0057] An accumulator includes an accumulator outer cylinder 1, the accumulator outer cylinder 1 is provided with the piston sealing structure as described above, the working temperature range of the accumulator is -60℃ to 80℃, and the working pressure range of the accumulator is 31.5MPa to 70MPa.

[0058] Since the accumulator is technically improved and has the beneficial effects at least as much as the piston sealing structure, the accumulator will not be described here.

[0059] The above disclosure is only some specific embodiments of the present application, but the embodiments of the present application are not limited thereto, and any changes that can be thought of by those skilled in the art shall fall within the protection scope of the present application.

Claims

1. A piston sealing structure, disposed inside the outer cylinder (1) of an accumulator, characterized in that, The piston sealing structure includes an accumulator piston (2) that can be slidably disposed in the outer cylinder (1) of the accumulator. Multiple annular grooves are sequentially opened on the outer peripheral wall of the accumulator piston (2) along the axial direction. The multiple annular grooves are sequentially provided with a support ring (3), a step seal, a main sealing assembly, a step seal, and a support ring (3) from the gas chamber side to the liquid chamber side. The step seal, as an auxiliary sealing component, includes an O-ring (5) and a V-shaped step seal sealing ring (4) fitted outside the O-ring (5). The V-shaped step seal sealing ring (4) has a pressure relief hole (41) circumferentially and a pressure relief groove (42) on the side of the V-shaped step seal sealing ring (4) away from the main sealing component. The O-ring (5) moves under pressure, causing the step seal to present two states. In the first state, the O-ring (5) moves closer to the main sealing assembly to block the pressure relief hole (41); In the second state, the O-ring (5) is moved away from the main sealing assembly, allowing the medium to flow through the pressure relief hole (41) to the pressure relief groove (42).

2. The piston sealing structure as described in claim 1, characterized in that, The inner wall of the V-shaped sealing ring (4) is provided with a V-shaped groove (43) and the outer wall is provided with a guide groove (44). The V-shaped groove (43) and the guide groove (44) are connected through the pressure relief hole (41).

3. The piston sealing structure as described in claim 2, characterized in that, The outer diameters of the two sides of the guide groove (44) are different. The groove edge near the main sealing assembly abuts against the inner wall of the accumulator outer cylinder (1), while the groove edge away from the main sealing assembly does not contact the inner wall of the accumulator outer cylinder (1).

4. The piston sealing structure as described in claim 1, characterized in that, The main sealing assembly includes a T-ring (6) and a protective ring (7). The protective ring (7) is symmetrically arranged on both sides of the T-ring (6), and the protective ring (7) is made of polytetrafluoroethylene.

5. The piston sealing structure as described in claim 4, characterized in that, The T-ring (6) is interference-fitted with the outer cylinder (1) of the accumulator.

6. The piston sealing structure as described in claim 1, characterized in that, A buffer gap is provided between the step seal and the support ring (3) on the same side of the main sealing assembly.

7. The piston sealing structure as described in claim 1, characterized in that, The O-ring (5) is made of hydrogenated nitrile rubber, and the V-type step seal ring (4) is made of polyether ether ketone and carbon fiber composite material.

8. The piston sealing structure as described in claim 5, characterized in that, The cross-section of the T-ring (6) is stepped, and the sealing surface that contacts the inner wall of the accumulator outer cylinder (1) is provided with an arc-shaped protrusion, and the arc of the arc-shaped protrusion is R0.5mm-R1.2mm.

9. The piston sealing structure as described in claim 8, characterized in that, On the outer wall of the accumulator piston (2), grease storage ring grooves are provided on both sides of the annular groove corresponding to the T-ring (6). The grease storage ring grooves are connected to the annular groove and are filled with grease.

10. An energy storage device, characterized in that: It includes an accumulator outer cylinder (1), and the accumulator outer cylinder (1) is provided with a piston sealing structure as described in any one of claims 1-9.

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