Hydraulic actuator piston rod dynamic seal protection device

Abstract

The invention discloses a dynamic seal protection device for a piston rod of a hydraulic actuator, and belongs to the technical field of sealing protection of spaceflight hydraulic actuators. The device comprises a flexible protective sleeve, a locking nut and a bolt head, one end of the flexible protective sleeve is connected with the end of the hydraulic cylinder, and the other end of the flexible protective sleeve is connected with a piston rod extending end and wraps the side, extending out of the hydraulic cylinder, of the piston rod; the flexible protective sleeve has a telescopic function and reciprocates along with the piston rod. The functions of oil absorption, fire prevention, heat prevention and the like are integrated, a multi-stage comprehensive active sealing protection system is formed, oil is actively absorbed through the flexible protection sleeve oil absorption layer, and the problems that the oil at the movable sealing part of the piston rod is accumulated into drops for a long time, the hydraulic oil pollutes external products, and the functions of other equipment are affected are solved.

Description

Technical Field

[0001] This invention relates to a dynamic sealing protection device for a hydraulic actuator piston rod, belonging to the field of sealing protection technology for aerospace hydraulic actuators. Background Technology

[0002] The piston rod is a key component in linear drive mechanisms such as hydraulic cylinders, reciprocating within the cylinder to transmit power. To prevent leakage of the working medium (such as hydraulic oil) and to prevent external contaminants from entering the cylinder, the dynamic seal of the piston rod is crucial. In existing technologies, one or more sealing rings (such as Step seals, Glyd rings, etc.) or a combination of seals are typically used as the main seal, with the industry sometimes adding a dust seal for external protection. However, under harsh operating conditions, such as high temperatures and open flames, the protective capability of the dust seal is limited, and it is itself a contact seal, subject to wear. Furthermore, in some critical equipment sectors, the equipment is numerous, complex, and compact; during long-term use of hydraulic servo actuators, micro-leakage may occur at the dynamic seal, accumulating and dripping, contaminating external products with hydraulic oil. In recent years, seal failure accidents under long-term operating conditions have become frequent, necessitating an integrated multi-functional protection solution. Relying solely on the above structure presents the following challenges:

[0003] 1) Fine dust, salt spray, etc. can easily adhere to the surface of the piston rod and be carried into the sealing lip as it moves, accelerating the wear of the seal and causing the seal to fail.

[0004] 2) Hard particles may scratch the machined surface of the piston rod, forming grooves, compromising the integrity of the seal, and causing permanent leakage;

[0005] 3) The material needs to absorb the leaked oil, and its high-temperature resistance and fire resistance also need to be considered. In high-temperature environments, ordinary rubber or plastic will melt and age, losing its protective function; in the case of hydraulic oil leakage, these materials do not have the ability to absorb oil and retard flames, and may instead become a fire hazard.

[0006] Patent CN103573743A discloses a protective hydraulic cylinder, including a cylinder body, piston, piston rod, cylinder head, and oil inlet. The piston is placed inside the cylinder body and fixedly connected to the piston rod, and a protective sleeve is provided on the piston rod. The protective sleeve is a retractable, pleated tube, with both ends connected to the cylinder body and piston rod respectively, serving to provide waterproofing, dustproofing, and corrosion protection against external elements, but it does not have functions such as oil absorption, high temperature resistance, or fire resistance.

[0007] Patent CN108412835A discloses a hydraulic cylinder with piston rod protection, including a cylinder body, piston, piston rod, cylinder head, and oil inlet; the piston is placed in the cylinder body and fixedly connected to the piston rod; a telescopic rubber sleeve is fitted on the piston rod; the two ends of the telescopic rubber sleeve are fixedly connected to the stop and the cylinder head, and a gap is left between the telescopic rubber sleeve and the piston rod; a vent hole is opened on the stop; an air filter is installed at the outer end of the vent hole to ensure that the inside of the telescopic rubber sleeve is connected to the outside, preventing external dust from entering. The telescopic rubber sleeve reduces friction through the gap design, but it does not have functions such as oil absorption, high temperature resistance, or fire resistance.

[0008] Patent CN219509936U discloses an external protective structure for a hydraulic cylinder, including a cylinder body with a piston rod inside. A guide sleeve is provided at the opening at one end of the cylinder body. One end of the piston rod passes through the center of the guide sleeve and connects to an clevis. A connecting sleeve is fixedly provided at the connection between the clevis and the piston rod. A telescopic dust cover is provided between the guide sleeve and the connecting sleeve. Multiple telescopic rods are provided between the guide sleeve and the connecting sleeve to support the dust cover and prevent it from sticking to the piston rod. This design is relatively complex but lacks functions such as oil absorption, high temperature resistance, and fire resistance. Summary of the Invention

[0009] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a dynamic seal protection device for hydraulic actuator piston rods. This piston rod dynamic seal protection device integrates functions such as oil suction, fire prevention, and heat protection into one device. It has a simple structure, high reliability, and can greatly improve the protection level of the piston rod sealing system.

[0010] The technical solution of this invention is:

[0011] A dynamic seal protection device for a hydraulic actuator piston rod includes a flexible protective sleeve, a lock nut, and a bolt head;

[0012] The hydraulic actuator includes a hydraulic cylinder and a piston rod mounted on the hydraulic cylinder, and the hydraulic cylinder and the piston rod are sealed together.

[0013] One end of the flexible protective sleeve is connected to the end of the hydraulic cylinder, and the other end is connected to the protruding end of the piston rod, covering the side of the piston rod protruding from the hydraulic cylinder; the flexible protective sleeve has a telescopic function and reciprocates with the piston rod.

[0014] The bolt head is connected to the protruding end of the piston rod;

[0015] The locking nut secures and presses against one end of the piston rod protruding from the flexible protective sleeve and locks the bolt head, so that the flexible protective sleeve forms a closed protective space.

[0016] Furthermore, the main body of the flexible protective sleeve is a protective corrugated tube composed of multiple layers of different materials, which, from the outside to the inside, are an outer protective layer, a heat-insulating layer, an oil-absorbing layer, and an inner protective layer;

[0017] The outer protective layer is made of reflective heat-insulating material;

[0018] The heat-resistant layer is a fireproof and heat-insulating layer made of flame-retardant and heat-insulating materials;

[0019] The oil-absorbing layer is made of an oil-loving polymer fiber material;

[0020] The inner protective layer is closely attached to the oil-absorbing layer and directly covers the piston rod. It is made of flame-retardant aramid fabric and has strong permeability, allowing the oil to be quickly absorbed by the oil-absorbing layer.

[0021] Furthermore, the layers of the protective corrugated pipe are sewn together with stitching thread made of a material with high temperature resistance and flame retardant properties. The stitching pattern is a grid with uniform spacing, which prevents slippage between the layers when the protective corrugated pipe expands and contracts.

[0022] Furthermore, the stitching pattern is a grid pattern with a spacing of 30mm.

[0023] Furthermore, the layers of the protective corrugated pipe are stitched together with flexible protective material, which is then cut into multiple petal shapes. Several petal-shaped flexible protective materials are stitched together to form a lantern-shaped structural unit. These lantern-shaped structural units are then stitched together sequentially to form the protective corrugated pipe, thus achieving the expansion and contraction function and structural support of the flexible protective sleeve.

[0024] Furthermore, 8 to 10 petal-shaped flexible protective materials are stitched together to form a lantern-shaped structural unit.

[0025] Furthermore, the protective bellows is provided with a first mounting flange and a second mounting flange at both ends respectively; the mounting surface of the first mounting flange is fitted to the outer end face of the hydraulic cylinder and is connected and fixed by a set of evenly distributed bolt assemblies; the second mounting flange has an L-shaped cross section, with the inner cylindrical surface fitted to the outer cylindrical surface of the piston rod, and the protruding overlapping surface fitted to the end face of the piston rod and fixed and pressed by a lock nut.

[0026] Furthermore, adjustable elastic clamps are added at both flange positions to ensure that the protective device can be reliably fixed to the hydraulic cylinder and piston rod.

[0027] Furthermore, the protective bellows is connected to the first and second mounting flanges at their joints via metal crimping to ensure reliable connection and sealing.

[0028] Furthermore, the oil-absorbing layer uses oil-absorbing felt, and the oil absorption capacity is set according to the actual product leakage failure situation and replacement frequency, preferably 0.1 ml / cm³. 2 .

[0029] Furthermore, the hydraulic cylinder includes a hydraulic cylinder end cover and a cylinder barrel; the hydraulic cylinder end cover is fixed to the front end of the cylinder barrel by a bolt assembly, and the seal between the hydraulic cylinder end cover and the cylinder barrel is a static seal, which is sealed by a sealing ring; the piston rod extends out from the middle of the hydraulic cylinder, and the piston rod and the hydraulic cylinder are dynamically sealed by a combined seal and a dustproof ring.

[0030] Furthermore, depending on the structural space of the hydraulic cylinder, the sealing ring can be configured as a double or multiple sealing rings to further improve sealing reliability.

[0031] The advantages of this invention compared to the prior art are:

[0032] (1) This invention proposes a piston rod dynamic sealing protection device that integrates functions such as oil absorption, fire prevention, and heat protection, forming a multi-level and comprehensive active sealing protection system. By actively absorbing oil through the oil absorption layer, it solves the problem of oil accumulating into drips and hydraulic oil contaminating external products, thereby affecting the function of other equipment.

[0033] (2) The outer layer of the flexible protective sleeve of the protective device proposed in this invention is composed of a reflective heat insulation layer and a fireproof heat insulation layer, which effectively isolates the high temperature radiation of the external environment, prevents the piston rod temperature from being too high, protects the sealing system, and extends the service life of the equipment.

[0034] (3) The protective device proposed in this invention adopts a flexible and retractable structure, which does not affect the normal reciprocating motion of the piston. It can be widely used in fields with high requirements for safety and reliability, such as metallurgy, casting, shipbuilding, engineering machinery, and aerospace. Attached Figure Description

[0035] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0036] Figure 1 This is a front cross-sectional view of the protective device according to an embodiment of the present invention;

[0037] Figure 2 This is a partial enlarged view of the protective device according to an embodiment of the present invention;

[0038] Figure 3 This is a diagram illustrating the composition of the flexible protective sleeve according to an embodiment of the present invention;

[0039] Figure 4 This is a schematic diagram of the composition of the flexible protective material according to an embodiment of the present invention;

[0040] Figure 5This is a schematic diagram of a petal-shaped flexible protective material according to an embodiment of the present invention;

[0041] Figure 6 This is a schematic diagram of a flexible protective material with a flat, round, lantern-shaped structural unit, as described in an embodiment of the present invention. Detailed Implementation

[0042] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0043] This invention proposes a dynamic seal protection device for the piston rod of a hydraulic actuator, such as... Figure 1 As shown, it includes piston rod 1, hydraulic cylinder end cover 2, cylinder barrel 3, bolt head 4, first fixing bolt assembly 5, flexible protective sleeve 6, locking nut 7, combined seal 8, dustproof ring 9, sealing ring 10, and second fixing bolt assembly 11.

[0044] The hydraulic cylinder end cap 2 is fixed to one end of the cylinder barrel 3 by the second fixing bolt assembly 11, such as Figure 2 As shown, the seal between the hydraulic cylinder end cover 2 and the cylinder barrel 3 is a static seal, achieved through a sealing ring 10. The sealing ring 10 can be configured as a double or multiple sealing rings depending on the structural space of the hydraulic cylinder, further improving sealing reliability. The piston rod 1 extends through the middle of the hydraulic cylinder end cover 2 and reciprocates. The dynamic seal between the piston rod 1 and the hydraulic cylinder end cover 2 is achieved through a combination of sealing elements 8, dust rings 9, and other structures. A flexible protective sleeve 6 is fitted over the piston rod 1 of the hydraulic cylinder. The two ends of the flexible protective sleeve 6 are connected to the hydraulic cylinder body (such as the hydraulic cylinder end cover 2 or the cylinder barrel 3, in this embodiment connected to the hydraulic cylinder end cover 2) and the protruding end of the piston rod 1 respectively via mounting flanges to achieve a sealed connection.

[0045] The flexible protective sleeve 6 is mainly composed of a protective corrugated pipe 601, a first mounting flange 602, and a second mounting flange 603, such as... Figure 3 As shown. The structural forms of the first mounting flange 602 and the second mounting flange 603 are matched to the interface of the hydraulic cylinder body and the protruding end of the piston rod 1. The joint between the protective bellows 601 and the first mounting flange 602 and the second mounting flange 603 is connected by means of metal crimping, etc., to ensure reliable connection and sealing. Furthermore, the sealing reliability can be improved by adding "O-rings" or "metal gaskets" at the joint surface.

[0046] The protective corrugated pipe 601 material consists of, from the outside in, an outer protective layer 6011, a heat-insulating layer 6012, an oil-absorbing layer 6013, and an inner protective layer 6014. (Example:) Figure 4 As shown, the four layers of materials with different properties and functions are sewn together with stitching material that has high temperature resistance and flame retardant properties to form a multi-layered flexible protective material with a certain hardness and thickness. The stitching pattern is a grid with uniform spacing (preferably 30mm) to ensure that the material layers do not slip when the protective corrugated pipe expands and contracts. The flexible protective material is cut into a "petal shape" with pointed ends, such as... Figure 5 As shown, multiple (preferably 8-10) "petal-shaped" flexible protective materials are stitched together to form a flattened, round "lantern-shaped" structural unit with smaller diameters at both ends and a larger diameter in the middle, such as... Figure 6 As shown, multiple "lantern-shaped" structural units are then spliced ​​and stitched together to form a protective corrugated pipe 601, realizing the telescopic function and structural support of the flexible protective sleeve 6. The quantity and diameter of the "lantern-shaped" protective material are determined by the telescopic stroke, piston rod diameter, etc., and the stitching is made of high-temperature resistant and flame-retardant material.

[0047] The outer protective layer 6011 is the outermost layer, made of reflective heat-insulating material, such as aluminum foil. Its high reflectivity reflects external radiation back, enhancing the overall heat insulation effect. It is attached to the outer surface of the heat-insulating layer 6012. The heat-insulating layer 6012 is a fireproof heat-insulating layer, made of flame-retardant heat-insulating material of appropriate thickness (such as silicone-based heat-insulating cloth), wrapping the oil-absorbing layer 6013. When exposed to fire, the heat-insulating layer 6012 rapidly expands to form a dense carbonized heat-insulating layer, effectively blocking flames and heat. The thickness of the heat-insulating layer 6012 can be reasonably set according to material characteristics, external high-temperature environment requirements, and working time; the preferred thickness is 1 mm. The oil-absorbing layer 6013 uses oil-absorbing felt, composed of oleophilic polymer fiber material. Its fiber structure can quickly absorb and lock in oil leaking from the surface of the piston rod 1. The oil absorption capacity of the oil-absorbing layer is reasonably set according to the actual product leakage failure situation and replacement frequency; the preferred capacity is 0.1 ml / cm³. 2 The inner protective layer 6014 is the innermost layer, closely attached to the oil-absorbing layer 6013, and directly facing the piston rod. It is composed of flame-retardant aramid cloth and has a strong penetrating ability, allowing oil to be quickly absorbed by the oil-absorbing layer 6013. Compared with oil-absorbing felt materials, it is less likely to produce excess material that affects the sealing performance, thus solving the problem of oil dripping and contaminating external products.

[0048] The mounting surface of the first mounting flange 602 is fitted to the outer end face of the hydraulic cylinder end cover 2, such as... Figure 1 As shown, it is connected and fixed by a set of evenly distributed first fixing bolts 5. The second mounting flange 603 has an L-shaped cross-section facing the piston rod (as shown). Figure 3As shown, the inner cylindrical surface of the second mounting flange 603 fits against the outer cylindrical surface of the piston rod, the overlapping inner surface of the L-shaped flange is pressed against the end face of the piston rod, the bolt head 4 is threadedly connected to the piston rod 1, and the second mounting flange 603 is fixed and tightened by the lock nut 7, and the bolt head 4 is locked, ensuring that the mounting surfaces of the first mounting flange 602 and the second mounting flange 603 are sealed to the corresponding connecting surfaces, forming a closed protective space. Furthermore, by adding adjustable elastic clamps at the flange positions at both ends, the protective device of the present invention can be further reliably fixed to the hydraulic cylinder and the piston rod.

[0049] The flexible protective sleeve 6 covers the outside of the extended end of the piston rod 1, preventing fine dust, salt spray, and other particles from easily adhering to the piston rod surface and being carried into the sealing lip during its movement, accelerating the wear of the seal and leading to seal failure. It also prevents hard particles from scratching the piston rod, forming grooves, compromising the seal integrity, and causing permanent leakage. The flexible protective sleeve 6 extends and retracts accordingly as the piston rod 1 reciprocates. If oil seeps from the piston rod 1, it is quickly absorbed by the oil-absorbing layer 6013, preventing dripping. When there is an open flame or high temperature externally, the outer protective layer 6011 and the heat-insulating layer 6012 effectively protect the internal piston rod 1, oil-absorbing layer 6013, and inner protective layer 6014. Even if the oil-absorbing layer 6013 and inner protective layer 6014 absorb oil, it is protected by the heat-insulating layer 6012 from direct ignition, greatly improving the safety of the equipment in hazardous environments.

[0050] This invention adds a protective device to the traditional dynamic sealing system. This not only effectively prevents dust but also actively absorbs leaked oil through its heat-insulating and oil-absorbing layers. It possesses excellent fire-retardant and high-temperature resistance properties and effectively isolates external heat radiation, forming a multi-level, comprehensive sealing and protection system to ensure the safe and stable operation of the piston rod and the entire actuation system. The specific beneficial effects are as follows:

[0051] 1) This protective device not only effectively prevents dust but also actively absorbs leaked oil. It possesses excellent fire resistance, flame retardancy, and high-temperature resistance, and effectively isolates external heat radiation, forming a multi-level, comprehensive sealing and protection system to ensure the safe and stable operation of the piston rod and the entire actuation system. The oil-absorbing layer actively absorbs oil, a proactive protective measure that prevents oil from accumulating and dripping, thus avoiding hydraulic oil contamination of external products and affecting the function of other equipment.

[0052] 2) This device can effectively protect the piston rod, reduce piston rod scratches and seal damage caused by oil, high temperature and open flame, extend the service life of the equipment, and reduce the maintenance frequency and cost of the equipment.

[0053] 3) The device adopts a flexible and retractable structure, and the "lantern-shaped" structure provides structural support without affecting the normal reciprocating motion of the piston. It has a simple and compact structure, strong applicability, and can be widely used in fields with high safety and reliability requirements, such as metallurgy, casting, shipbuilding, engineering machinery, and aerospace.

[0054] 4) Adjustable clamps and bolts are used for fixing, making the installation of the protective device and piston rod convenient and the sealing reliable.

[0055] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

[0056] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A dynamic seal protection device for a hydraulic actuator piston rod, characterized in that, Includes flexible protective sleeves, lock nuts, and bolt heads; The hydraulic actuator includes a hydraulic cylinder and a piston rod mounted on the hydraulic cylinder, and the hydraulic cylinder and the piston rod are sealed together. One end of the flexible protective sleeve is connected to the end of the hydraulic cylinder, and the other end is connected to the protruding end of the piston rod, covering the side of the piston rod protruding from the hydraulic cylinder; the flexible protective sleeve has a telescopic function and reciprocates with the piston rod. The bolt head is connected to the protruding end of the piston rod; The locking nut secures and presses against one end of the piston rod protruding from the flexible protective sleeve and locks the bolt head, so that the flexible protective sleeve forms a closed protective space.

2. The hydraulic actuator piston rod dynamic seal protection device according to claim 1, characterized in that, The flexible protective sleeve is composed of multiple layers of corrugated tubing made of different materials, consisting of an outer protective layer, a heat-insulating layer, an oil-absorbing layer, and an inner protective layer from the outside to the inside. The outer protective layer is made of reflective heat-insulating material; The heat-resistant layer is a fireproof and heat-insulating layer made of flame-retardant and heat-insulating materials; The oil-absorbing layer is made of an oil-loving polymer fiber material; The inner protective layer is closely attached to the oil-absorbing layer and directly covers the piston rod. It is made of flame-retardant aramid fabric and has permeability, allowing the oil to be absorbed by the oil-absorbing layer.

3. The hydraulic actuator piston rod dynamic seal protection device according to claim 2, characterized in that, The layers of the protective corrugated pipe are sewn together with stitching made of a material with high temperature resistance and flame retardant properties. The stitching pattern is a grid with uniform spacing, which prevents the layers from slipping when the protective corrugated pipe expands and contracts.

4. A dynamic seal protection device for a hydraulic actuator piston rod according to claim 3, characterized in that, The stitching pattern is a grid pattern with a spacing of 30mm.

5. A dynamic seal protection device for a hydraulic actuator piston rod according to claim 2, characterized in that, The layers of the protective corrugated pipe are stitched together with flexible protective material. The flexible protective material is cut into multiple petal shapes. Several petal-shaped flexible protective materials are stitched together to form a lantern-shaped structural unit. Multiple lantern-shaped structural units are spliced ​​together one after another to form the protective corrugated pipe, realizing the expansion and contraction function and structural support of the flexible protective sleeve.

6. A dynamic seal protection device for a hydraulic actuator piston rod according to claim 5, characterized in that, Eight to ten petal-shaped flexible protective materials are sewn together to form a lantern-shaped structural unit.

7. A dynamic seal protection device for a hydraulic actuator piston rod according to claim 2, characterized in that, The protective bellows has a first mounting flange and a second mounting flange at both ends respectively; the mounting surface of the first mounting flange is fitted to the outer end face of the hydraulic cylinder and is connected and fixed by a set of evenly distributed bolt assemblies; the second mounting flange has an L-shaped cross section, with the inner cylindrical surface fitted to the outer cylindrical surface of the piston rod, and the protruding overlapping inner surface fitted to the end face of the piston rod and fixed and pressed by a lock nut.

8. A dynamic seal protection device for a hydraulic actuator piston rod according to claim 7, characterized in that, The protective bellows is connected to the first and second mounting flanges at their joints by metal crimping, ensuring reliable connection and sealing.

9. A dynamic seal protection device for a hydraulic actuator piston rod according to claim 2, characterized in that, The oil-absorbing layer uses oil-absorbing felt, and its oil absorption capacity is set according to the actual product leakage failure situation and replacement frequency, preferably 0.1ml / cm³. 2 .

10. A dynamic seal protection device for a hydraulic actuator piston rod according to claim 1, characterized in that, The hydraulic cylinder includes a hydraulic cylinder end cover and a cylinder barrel; the hydraulic cylinder end cover is fixed to the front end of the cylinder barrel by a bolt assembly, and the seal between the hydraulic cylinder end cover and the cylinder barrel is a static seal, which is sealed by a sealing ring; the piston rod passes through the middle of the hydraulic cylinder, and the piston rod and the hydraulic cylinder are dynamically sealed by a combination of sealing elements and a dustproof ring.

Images