Anti-seismic type leakage-proof hydraulic cylinder

Abstract

The application relates to the technical field of hydraulic cylinders, and discloses an anti-seismic and anti-leakage hydraulic cylinder, which comprises a cylinder barrel, a piston rod, a base and a top cover. The base and the top cover are respectively assembled at the two ends of the cylinder barrel, so that a closed cavity is formed in the cylinder barrel. A piston connected with the piston rod is arranged in the cavity. The piston rod penetrates out of the top cover. The piston divides the cavity in the cylinder barrel into two cavities which are not communicated with each other. A rodless cavity is formed between the piston and the base, and a rod cavity is formed between the piston and the top cover. A sealing element is arranged between the piston and the inner wall of the cylinder barrel. An annular groove is arranged on the contact surface between the piston and the inner wall of the cylinder barrel. The annular groove is arranged on the side of the sealing element close to the rod cavity. The side of the piston close to the rod cavity is provided with a pressure relief hole. The pressure relief hole is communicated with the rod cavity, and the annular groove and the pressure relief hole are also communicated with each other.

Description

Technical Field

[0001] This invention relates to the field of hydraulic cylinder technology, specifically to a shock-resistant and leak-proof hydraulic cylinder. Background Technology

[0002] Hydraulic cylinders, as core actuators in hydraulic transmission systems, are widely used in various equipment requiring linear reciprocating motion, such as engineering machinery, metallurgical equipment, ship steering gear, and hydraulic gate hoists. The basic structure of a hydraulic cylinder typically consists of a cylinder barrel, cylinder head, piston, and piston rod. Oil is alternately supplied to the rod-side and rodless-side chambers separated by the piston, utilizing the pressure difference between the two chambers to drive the piston and move the load. During cylinder operation, hydraulic oil, under high pressure, has a tendency to spontaneously flow towards low-pressure areas; this physical characteristic is the fundamental driving force behind hydraulic leakage. Hydraulic leakage is divided into two categories: internal leakage and external leakage. Internal leakage refers to oil flow between the high-pressure and low-pressure chambers within the cylinder, while external leakage refers to oil seeping from the inside of the cylinder into the external environment. The reliability of the seals directly determines the volumetric efficiency and long-term operational stability of the hydraulic cylinder.

[0003] In conventional hydraulic cylinder structures, when the piston rod is fully retracted to its limit stroke position, to prevent the piston from directly impacting the cylinder bottom cover, the rodless chamber typically lacks a reliable stroke limiting structure or buffer device. This results in the oil volume in the rodless chamber being compressed to an extremely low level the instant the piston or piston rod end contacts the cylinder bottom cover, almost completely emptying the oil at the inlet. At this moment, a peak pressure difference far exceeding the rated working pressure is instantaneously generated between the rodless and rod chambers. This extreme pressure difference directly affects the sealing assembly between the piston and the cylinder wall. Although commonly used lip seals have a self-tightening characteristic where the lip fits tighter with increasing pressure, abnormally high pressure differences can exceed the seal's design pressure limit, causing the sealing lip to flip or become unstable. This leads to the sealing surface momentarily separating from the mating surface, resulting in significant instantaneous internal leakage. The existing hydraulic cylinder piston structure lacks an effective means to balance the pressure gradient under the above extreme working conditions. The seals need to directly bear the full pressure drop from the high-pressure chamber to the low-pressure chamber, which is prone to failure under pressure shock conditions. This not only reduces the volumetric efficiency of the hydraulic cylinder, but also accelerates the wear of the seals and the inner wall of the cylinder, seriously affecting the working accuracy and service life of the hydraulic cylinder. Summary of the Invention

[0004] (I) Technical problem to be solved: In view of the shortcomings of the existing technology, the present invention provides a shock-resistant and leak-proof hydraulic cylinder, which has the advantages of shock resistance and leak prevention, and solves the problem of easy leakage due to pressure difference on both sides of the piston.

[0005] (II) Technical Solution: To achieve the above-mentioned anti-vibration and anti-leakage objectives, the present invention provides the following technical solution: an anti-vibration and anti-leakage hydraulic cylinder, comprising a cylinder barrel, a piston rod, a base, and a top cover. The cylinder barrel is fitted with a base and a top cover at both ends, forming a closed cavity inside the cylinder barrel. A piston connected to the piston rod is provided inside the cavity. The piston rod extends out from the top cover. The piston divides the cavity in the cylinder barrel into two non-communicating cavities. The cavity between the piston and the base is a rodless cavity, and the cavity between the piston and the top cover is a rod cavity. A sealing element is provided between the piston and the inner wall of the cylinder barrel, and an annular groove is provided on the contact surface between the piston and the inner wall of the cylinder barrel. The annular groove is located on the side of the sealing element near the rod cavity. A pressure relief hole is provided on the side of the piston facing the rod cavity, and the pressure relief hole communicates with the rod cavity. At the same time, the annular groove and the pressure relief hole are connected.

[0006] The piston rod is located inside the cylinder at one end, which is the piston rod end. The piston rod end passes through the piston and has external threads. It is connected and fixed to the piston by a lock nut, so that the piston and piston rod can move synchronously.

[0007] At least one pressure relief hole is provided, which is formed by drilling. A flow channel is provided between the pressure relief hole and the annular groove. The flow channel connects the annular groove and the pressure relief hole. At the same time, the diameter of the flow channel is smaller than the diameter of the pressure relief hole and the width of the annular groove.

[0008] The sealing element includes a wear-resistant ring and a piston seal, and the piston seal has a wear-resistant ring on both the rodless chamber side and the rod chamber side.

[0009] The piston is provided with a bronze ring on the contact surface with the inner wall of the cylinder, and the bronze ring is located on the side of the annular groove near the rod chamber.

[0010] Two annular grooves are provided, and both are connected to the pressure relief hole through flow channels. The annular grooves are respectively provided on both sides of the wear-resistant ring on the side of the seal near the rod chamber. At the same time, both annular grooves are located on the side of the piston seal away from the rodless chamber.

[0011] The cylinder is provided with rodless chamber oil port and rod chamber oil port for injecting fluid into the rodless chamber and rod chamber respectively.

[0012] The cylinder is provided with an oil port block, which integrates inlet and return oil passages and control valves. The oil port block is connected to the rodless chamber oil port through an oil pipe, and the oil port block can be connected to the rod chamber oil port through a pipeline.

[0013] A base earring is fixed on the base, and a piston rod earring is fixed on the top cover. The base earring and piston rod earring are used to connect devices that move relative to each other. A radial joint bearing is provided inside the piston rod earring.

[0014] The cylinder is fitted with a sleeve, which is fixedly connected to the cylinder. A bracket is provided on one side of the sleeve, and a base ear is provided on the bracket. A piston rod ear is fixed on the top cover. The base ear and the piston rod ear are arranged on the same plane, and a radial joint bearing is provided inside the base ear and the piston rod ear.

[0015] (III) Beneficial Effects: Compared with the prior art, the present invention provides a shock-resistant and leak-proof hydraulic cylinder, which has the following beneficial effects: 1. This shock-resistant and leak-proof hydraulic cylinder, through the synergistic effect of the annular groove on the outer circle of the piston, the pressure relief hole and the damping flow channel connecting the rod chamber, reconstructs the pressure distribution at the sealing interface. When the piston rod retracts to its limit position and the volume of the rodless chamber is extremely compressed, generating an instantaneous peak high pressure, the annular groove and the pressure relief hole ensure that the pressure on the side of the seal near the rod chamber remains uniform with that of the rod chamber. The huge pressure difference that originally acted directly on both sides of the seal is transformed into a local pressure difference between the rodless chamber and the annular groove. Since the volume of the annular groove is extremely limited, even if a small amount of oil is squeezed into the groove due to high pressure, the resulting volume loss is negligible and will not cause significant leakage. Simultaneously, the flow channel section connecting the annular groove and the pressure relief hole tightens, forming a throttling damping effect. When oil rushes into the annular groove under high pressure impact, the damping effect effectively dissipates the kinetic energy of the pressure fluctuation, "shaving off and filling the valley" of the sharp pressure peaks. This not only prevents the sealing lip from overturning, becoming unstable, and leaking a large amount of liquid instantaneously under extreme pressure differentials, but also significantly reduces the hydraulic shock and mechanical vibration generated when the piston hits the base, giving the cylinder excellent vibration resistance. After the piston has completely stopped, the pressure gradient on both sides of the seal returns to normal, and the material's own high-pressure self-tightening characteristics allow for reliable sealing, blocking subsequent internal leakage and ensuring long-term sealing performance. In addition, this design brings several benefits not directly mentioned: the annular groove can serve as a storage cavity for collecting oil debris, trapping trace amounts of oil scraped from the seals and small impurities entering the system, preventing hard particles from repeatedly crushing and damaging the sealing lip and cylinder wall during piston reciprocation, thus slowing down the abrasive wear process; the oil in the rod chamber continuously wets the annular groove area through the pressure relief hole, significantly improving the lubrication and heat dissipation conditions between the piston outer surface and the seals, reducing frictional resistance and the risk of local overheating, and suppressing vibration or abnormal noise caused by insufficient lubrication; the damping and throttling effect of the flow channel can also effectively attenuate the high-frequency pressure pulsation of the hydraulic system, making the cylinder move more smoothly and quietly under alternating loads and frequent reversals, reducing the probability of cavitation and noise; furthermore, under strong external vibrations or load fluctuations, the pressure in the annular groove and rod chamber remains dynamically balanced, preventing the seals from being damaged by fatigue caused by alternating pressure pulses, further enhancing the overall machine's shock resistance and durability under harsh working conditions. The entire solution utilizes only the piston body to machine holes, grooves, and throttling paths, thus eliminating the pressure spikes at extreme positions at the source. Without adding any external components, it achieves multiple benefits such as leak prevention, impact resistance, vibration reduction and noise reduction, and extended service life of seals and cylinder. The structure is simple and the effect is outstanding.

[0016] 2. This shock-resistant, leak-proof hydraulic cylinder, through a design of double annular grooves and graded pressure-equalizing flow channels, constructs a multi-stage pressure buffer barrier on the rod-side of the seal and wear ring, transforming the originally single pressure differential abrupt change into a step-like, gradual transition. When a momentary high-pressure impact occurs in the rodless chamber, the high-pressure oil, after passing through the tiny gap in the piston seal, does not directly face the low-pressure environment of the rod chamber, but instead sequentially enters the first and second annular grooves. Since each groove is connected to the pressure relief hole and the rod chamber through a flow channel with a throttling effect, the pressure gradually decreases between the two annular grooves. The wear ring is precisely located in this pressure transition zone, and the pressure difference on both sides is effectively decomposed and weakened, thus avoiding uneven wear, localized stress concentration, or material extrusion damage to the wear ring caused by bearing a large pressure difference on one side. The peak value and rate of change of the pressure pulse are significantly reduced due to the graded damping effect, and the sealing lip maintains a stable fit in a relatively gentle pressure differential environment, fundamentally suppressing lip flipping and instantaneous leakage. The double annular grooves increase the buffer volume for oil containment and impurity deposition, enabling more efficient capture of fine particles intruding into the system and preventing them from circulating and crushing at the sealing interface. The wear-resistant ring is placed between the two grooves, and the oil in the annular grooves can continuously wet the inner and outer surfaces of the wear-resistant ring, improving its critical dry friction condition, delaying wear, and reducing abnormal noise during operation. The graded pressure buffer significantly suppresses the alternating stress amplitude between the seal and the wear-resistant ring, alleviating the risk of material fatigue cracking. Under the conditions of frequent reciprocating motion and drastic pressure changes in the hydraulic cylinder, the double groove structure can also balance the axial heat distribution and avoid local heat accumulation, thereby comprehensively improving the impact resistance life and sealing reliability of the hydraulic cylinder.

[0017] 3. This shock-resistant, leak-proof hydraulic cylinder utilizes a combination of an external sleeve, a lateral offset bracket, and a spherical bearing to create multiple vibration attenuation and stress optimization paths. When strong vibrations from external equipment are transmitted through the piston rod clevis, the vibration energy is first absorbed by the spherical bearing through frictional sliding of the spherical mating pair and shear dissipation of the internal lubricating film. As the vibration continues to propagate to the cylinder body, the fixed connection interface between the cylinder outer wall and the sleeve, due to the microscopic heterogeneity of the material and contact damping, converts some of the mechanical energy into heat energy for dissipation. At the same time, the sleeve significantly increases the radial stiffness and mass inertia of the cylinder body, reducing the inherent vibration sensitivity of the entire machine. The lateral offset cantilever bracket undergoes slight elastic deformation under alternating loads, further dissipating the vibration kinetic energy. This significantly reduces the vibration intensity ultimately transmitted to the base clevis, thereby protecting the external equipment and the connecting structure. The offset bracket alters the installation geometry of the hydraulic cylinder, creating a lever arm between the base connection point and the piston rod axis. Under lateral stress, the bending deformation of the bracket can share part of the bending moment, reducing the bending stress on the cylinder body and connecting threads. When the hydraulic cylinder is used to drive actuators with severe vibrations, the self-aligning capability of the spherical bearing can compensate for installation deviations and dynamic deflection, preventing the piston rod from bearing additional lateral forces, thereby reducing the risk of piston rod seal wear and external leakage. The welded sleeve and bracket form an integral rigid frame, which helps suppress cylinder resonance under harsh working conditions, making the cylinder movement smoother and comprehensively improving the structural integrity and durability of the hydraulic cylinder in vibration environments. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a side view of the cylinder of the present invention; Figure 3 This is a top view of the cylinder of the present invention; Figure 4 This is a detailed schematic diagram of the annular groove in Embodiment 1 of the present invention; Figure 5 This is a detailed schematic diagram of the annular groove in Embodiment 2 of the present invention; Figure 6 This is a top view of the bracket in Embodiment 3 of the present invention; Figure 7 This is a side view of the bracket in Embodiment 3 of the present invention.

[0019] In the diagram: 1. Cylinder; 2. Piston rod; 11. Rodless chamber; 12. Rod chamber; 21. Piston rod end; 3. Piston; 31. Locking nut; 32. Wear ring; 33. Piston seal; 34. Bronze ring; 35. Annular groove; 351. Pressure relief hole; 4. Sleeve; 41. Bracket; 5. Oil port block; 51. Oil pipe; 52. Rodless chamber oil port; 6. Rod chamber oil port; 101. Base; 102. Top cover; 1011. Base lug; 1021. Piston rod lug. Detailed Implementation

[0020] The technical solutions of 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see Figures 1-4 An anti-vibration, leak-proof hydraulic cylinder includes a cylinder barrel 1, a piston rod 2, a base 101, and a top cover 102. The cylinder barrel 1 is a cylindrical hollow cylinder, and the piston rod 2 is a solid long rod structure. The base 101 and top cover 102 are respectively mounted at both ends of the cylinder barrel 1. Static sealing rings are provided at the mating surfaces of the base 101 and top cover 102 with the cylinder barrel 1, forming a closed cavity inside the cylinder barrel 1. This cylindrical cavity is used to contain hydraulic oil and provide space for the piston 3 to move. A piston 3, which is connected to the piston rod 2, is located within this cavity. The piston 3 is a cylindrical slider. The outer surface of piston 3 is clearance-fitted with the inner surface of cylinder 1. Piston rod 2 protrudes from top cover 102. A through hole for piston rod 2 is machined in the center of top cover 102, and a piston rod seal and dust seal are installed in the through hole. Piston 3 divides the cylinder 1 into two non-communicating cavities: a rodless cavity 11 between piston 3 and base 101, and a rod cavity 12 between piston 3 and top cover 102. Both the rodless cavity 11 and the rod cavity 12 are connected to the hydraulic system via subsequent oil ports. A seal is provided between piston 3 and the inner wall of cylinder 1 to prevent the piston rod from passing through. An oil leakage channel is provided along the outer circumference of the piston 3 between the rod chamber 11 and the rod cavity 12. An annular groove 35 is provided on the contact surface between the piston 3 and the inner wall of the cylinder 1. The annular groove 35 is a rectangular or arc-shaped cross-section groove cut circumferentially on the outer circumference of the piston 3. The axial position of the annular groove 35 is determined according to the position of the seal. The annular groove 35 is located on the side of the seal closer to the rod cavity 12, that is, the annular groove 35 is located in the outer circumference area between the seal mounting groove and the end face of the piston 3 facing the rod cavity 12. A pressure relief hole 351 is provided on the side of the piston 3 facing the rod cavity 12. The pressure relief hole 351 is for oil leakage from the piston... A straight or oblique hole is drilled inward along the axial direction of the piston 3 towards the end face of the rod chamber 12. The pressure relief hole 351 is connected to the rod chamber 12. The opening of the pressure relief hole 351 is located on the end face of the piston 3, allowing the oil in the rod chamber 12 to freely enter the pressure relief hole 351. At the same time, the annular groove 35 and the pressure relief hole 351 are connected. A flow channel is machined inside the piston 3, connecting the bottom diameter of the annular groove 35 to the pressure relief hole 351. The flow channel can be realized through a radial hole or an oblique hole. The flow cross-sectional area of ​​the flow channel is smaller than the cross-sectional area of ​​the pressure relief hole 351 and the cross-sectional area of ​​the annular groove 35, so as to produce an appropriate damping effect on the oil flow.

[0022] The movement of a hydraulic cylinder is essentially driven by a pressure difference in the hydraulic fluid within the chambers on either side of piston 3. Specifically, the hydraulic oil pressure in the rodless chamber 11 is unequal to that in the rod chamber 12, allowing the fluid to push piston 3 and drive piston rod 2 towards the lower-pressure chamber. Liquids have inherent fluidity and, under unconstrained conditions, will always spontaneously flow from high-pressure to low-pressure areas. This is the core driving force behind oil leakage. Hydraulic oil leakage is classified into two types: internal leakage (oil flowing between high and low-pressure chambers) and external leakage (oil seeping to the outside of the cylinder). Pressure difference is the fundamental driving force behind all hydraulic leaks. When piston rod 2 is pushed out, high-pressure oil is supplied to the rodless chamber 11, and high-pressure oil is supplied to the rod chamber 12. Oil returns to chamber 12. Due to stroke protection limitations, such as when piston 3 moves close to top cover 102 and is stopped, a certain amount of oil is always retained in the rod chamber 12. This retained oil acts as a buffer. However, when piston rod 2 retracts, high-pressure oil is supplied to the rod chamber 12 and oil returns to the rodless chamber 11. This does not guarantee that piston rod 2 will retract completely. The rodless chamber 11 has virtually no limit structure and no protruding structure to restrict the stroke of piston 3. As a result, at the moment piston 3 or piston rod end 21 contacts the inner surface of base 101, the oil level in the rodless chamber 11 is extremely low and almost completely emptied, producing a very low oil level. Large pressure differences, with instantaneous pressure differences reaching several times the normal operating pressure, can disrupt the self-tightening property of seals, such as lip seals, where higher pressure results in a tighter lip seal. The instantaneous peak pressure far exceeds the seal's rated pressure, causing the seal lip to flip and become unstable, leading to the sealing surface separating from the mating surface and resulting in a large, instantaneous leak. This is especially true during the movement of piston 3, when piston 3 is still moving and the seal is not fully engaged. The annular groove 35 and the pressure relief hole 351 transform the pressure difference between the rodless chamber 11 and the rod chamber 12 into the pressure difference between the rodless chamber 11 and the annular groove 35. The pressure difference between the annular groove 35 and the rod chamber 12 is equalized by the pressure relief hole 351 connecting the annular groove 35 and the rod chamber 12, thus eliminating the pressure difference between them. Although a pressure difference still exists between the rodless chamber 11 and the annular groove 35, the volume of hydraulic oil contained in the annular groove 35 is not large, and its volume is much smaller than that of the rodless chamber 11. Therefore, it will not cause significant leakage in an instant. At the same time, when the piston 3 comes to a complete stop, the pressure gradient on both sides of the seal tends to stabilize, and the seal can effectively self-tighten to prevent subsequent leakage, thereby ensuring the sealing performance of the cylinder during long-term operation.

[0023] The piston rod 2 is located inside the cylinder 1 at one end, which is called the piston rod end 21. The diameter of the piston rod end 21 is smaller than the diameter of the main body of the piston rod 2, forming a stepped surface for axial positioning of the piston 3. The piston rod end 21 passes through the piston 3. The piston 3 has a through hole at its center that mates with the piston rod end 21. The through hole and the piston rod end 21 are in clearance fit. The piston rod end 21 is machined with external threads. The length of the threaded portion meets the requirements for the locking nut 31 to be engaged. The locking nut 31 is connected and fixed to the piston 3. The locking nut 31 is tightened on the thread of the piston rod end 21 and presses against the end face of the piston 3. A spring washer can be used to prevent loosening, so that the piston 3 and the piston rod 2 can move synchronously, that is, the piston 3 moves along with the piston rod 2 when the piston rod 2 moves back and forth.

[0024] At least one pressure relief hole 351 is provided and is formed by drilling. The axis of the pressure relief hole 351 can be parallel to the axis of the piston 3. After drilling, the hole opening is deburred. A flow channel is provided between the pressure relief hole 351 and the annular groove 35. The flow channel is a through hole drilled from the bottom end or side wall of the pressure relief hole 351 to the bottom wall of the annular groove 35. The flow channel connects the annular groove 35 and the pressure relief hole 351 to ensure that the oil flows between the two. At the same time, the diameter of the flow channel is smaller than the diameter of the pressure relief hole 351 and the groove width of the annular groove 35. The smaller diameter of the flow channel plays a throttling role and avoids the pressure change in the annular groove 35 from impacting the seal.

[0025] The sealing element includes a wear-resistant ring 32 and a piston seal 33. The wear-resistant ring 32 is an open circular ring made of wear-resistant non-metallic material. The piston seal 33 is a lip seal or a combination seal. The piston seal 33 has a wear-resistant ring 32 on the side near the rodless chamber 11 and the side near the rod chamber 12. The two wear-resistant rings 32 are respectively embedded in the annular grooves on the outer circle of the piston 3 located on both sides of the piston seal 33, which are used to bear the radial force of the piston 3 and prevent the piston seal 33 from being squeezed out by high pressure.

[0026] A bronze ring 34 made of bronze is provided on the contact surface between the piston 3 and the inner wall of the cylinder 1. The bronze ring 34 is an elastic open ring made of metal and is embedded in the mounting ring groove on the outer circle of the piston 3. The outer circle surface of the bronze ring 34 and the inner wall of the cylinder 1 are a sliding friction pair. The bronze ring 34 is located on the side of the annular groove 35 near the rod chamber 12, that is, the bronze ring 34 is located axially between the annular groove 35 and the rod chamber 12. The bronze ring 34 can improve the guiding accuracy of the piston 3 and bear part of the lateral load.

[0027] The cylinder 1 is provided with a rodless cavity port 52 and a rod cavity port 6 for injecting fluid into the rodless cavity 11 and the rod cavity 12. The rodless cavity port 52 is connected to the rodless cavity 11, and the rod cavity port 6 is connected to the rod cavity 12. The ports can be machined into internal or external thread joints to facilitate the connection of external hydraulic pipelines. The cylinder 1 is provided with an oil port block 5. The oil port block 5 is a cuboid or irregularly shaped metal block, which is fixed to the outer wall of the cylinder 1 by screws or welding. The oil port block 5 integrates inlet and outlet oil circuits and control valves. The control valves can be balance valves, one-way throttle valves, etc., used to control the cylinder's operating speed or lock it. The oil port block 5 is connected to the rodless chamber oil port 52 through an oil pipe 51. The oil pipe 51 is a high-pressure resistant steel wire braided hose with pipe joints at both ends, which are respectively connected to the oil outlet of the oil port block 5 and the rodless chamber oil port 52. The oil port block 5 can be connected to the rod chamber oil port 6 by setting up a pipeline, that is, another oil pipe is led out from the oil port block 5 and connected to the rod chamber oil port 6, or an oil port that connects directly to the rod chamber oil port 6 is set on the oil port block 5, so as to realize the complete connection of the hydraulic circuit.

[0028] A base ear 1011 is fixed on the base 101, and a piston rod ear 1021 is fixed on the top cover 102. The base ear 1011 can be an integral forging or welded part with the base 101. The piston rod ear 1021 can be fixed to the outer end of the piston rod 2 or the outside of the top cover 102. The base ear 1011 and the piston rod ear 1021 are used to connect relatively moving equipment. They are hinged to the equipment by a pin passing through the ear hole. A radial joint bearing is provided inside the piston rod ear 1021. The outer ring of the radial joint bearing is press-fitted into the ear hole, and the inner ring can rotate and swing relative to the outer ring to compensate for installation errors and buffer radial impact.

[0029] Example 2 See Figure 5In this embodiment, the overall structure is the same as in Embodiment 1, except for the number of annular grooves 35. There are two annular grooves 35, which are arranged side by side at intervals along the piston 3 axis and are connected to the pressure relief hole 351 through a flow channel. The flow channel can be two branches that branch off from the pressure relief hole 351 and lead to the two annular grooves 35 respectively. The annular grooves 35 are respectively set on both sides of the wear-resistant ring 32 on the side of the rod cavity 12 in the seal. That is, one annular groove 35 is located on the side of the wear-resistant ring 32 facing the rodless cavity 11, and the other annular groove 35 is located on the side of the wear-resistant ring 32 facing the rod cavity 12. In this way, the wear-resistant ring 32 is located between the two annular grooves 35. At the same time, both annular grooves 35 are located on the side of the piston seal 33 away from the rodless cavity 11. That is, the piston seal 33 is still located on the side of the two annular grooves 35 close to the rodless cavity 11. The two annular grooves 35 form a graded pressure equalization structure. When a pressure shock occurs during the operation of the hydraulic cylinder, high-pressure oil attempts to pass through the tiny gap of the piston seal 33 from the rodless chamber 11 side. It first enters the first annular groove 35 near the piston seal 33. This annular groove 35 is connected to the pressure relief hole 351 through a flow channel and indirectly connected to the rod chamber 12. Due to the throttling effect of the flow channel and the volume of the pressure relief hole 351, the pressure in the first annular groove 35 does not rise instantaneously, but builds up slowly. At the same time, the pressure in the first annular groove 35 is connected to the second annular groove 35 through the tiny gap or dedicated flow channel at the wear ring 32. The second annular groove 35 is also connected to the pressure relief hole 351. In this way, a pressure gradient is formed between the two annular grooves 35, so that the pressure difference between the wear ring 32 and the piston seal 33 changes from a single sudden change to two step transitions, which greatly weakens the peak value and rate of change of the pressure pulse, thereby preventing the sealing lip from flipping or becoming unstable due to the instantaneous high pressure difference. Even if the piston 3 moves rapidly to the bottom limit position, and the rodless chamber 11 generates instantaneous negative or high pressure, both annular grooves 35 can dynamically adjust the pressure distribution, so that the seal is always in a relatively stable differential pressure environment, which significantly improves the anti-leakage capability and impact resistance life of the hydraulic cylinder.

[0030] Example 3 See Figure 6In this embodiment, the overall structure of the cylinder 1 and piston 3 is the same as in Embodiment 1. A sleeve 4 is fitted over the cylinder 1. The sleeve 4 is a cylindrical outer shell made of metal or composite material, and its inner diameter matches the outer diameter of the cylinder 1. The sleeve 4 is fixedly connected to the cylinder 1 by welding. After welding the sleeve 4, the inside of the cylinder 1 is machined. A bracket 41 is provided on one side of the sleeve 4. The bracket 41 is a plate-shaped piece extending radially from the outer surface of the sleeve 4 and is welded and fixed to the sleeve 4. A base lug 1011 is provided on the bracket 41, and the base lug 1011 is welded to the end of the bracket 41. The pin hole axis of the base lug 1011 is perpendicular to the axis of the cylinder 1. A piston rod lug 1021 is fixed on the top cover 102, and the piston rod lug 1021 is directly fixed to the piston rod. At the extended end of 2, the base lug 1011 and piston rod lug 1021 are coplanar, meaning that the center line of the pin hole of the two lugs and the axis of cylinder 1 are in the same plane, so that the hydraulic cylinder is subjected to symmetrical force when installed laterally. The base lug 1011 and piston rod lug 1021 are equipped with radial spherical bearings. The outer ring of the spherical bearing is interference-fitted with the lug hole, and the inner ring can deflect relative to the outer ring. The spherical bearing can absorb and buffer the vibration during equipment operation and protect the cylinder body. At the same time, its design also takes into account the characteristics of lateral installation. The lateral installation bracket 41 and the base lug 1011 change the spacing between the original structures connecting the two ends of the hydraulic cylinder. The lateral offset of the bracket 41 changes the straight distance and relative position between the base connection point and the piston rod connection point. When subjected to vibration, the vibration force is transmitted from the piston rod clevis 1021, through the piston rod 2, piston 3, and hydraulic medium into the cylinder 1, and then conducted to the sleeve 4 via the outer wall of the cylinder 1. Due to the microscopic unevenness and material damping characteristics of the fixed connection interface between the sleeve 4 and the cylinder 1, some of the vibration mechanical energy can be converted into heat energy and dissipated. At the same time, the support 41, as a cantilever structure, undergoes slight elastic deformation, further dissipating the vibration energy. Finally, the vibration transmitted to the external structure via the base clevis 1011 is significantly attenuated. In addition, the spherical friction and internal lubrication film of the spherical bearing itself also have a damping effect, which can absorb high-frequency vibration peaks and prevent vibration from directly impacting the cylinder seals and threaded connections. When the piston rod clevis 1021 is connected to equipment that is prone to vibration, such as motors, the vibration amplitude transmitted to the base clevis 1011 will be significantly reduced. This is because the sleeve 4 and support 41 increase the overall stiffness and damping, and the spherical bearing absorbs some of the vibration energy, thus weakening the vibration transmitted to the base clevis 1011, which helps to extend the service life of the cylinder and the equipment.

[0031] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0032] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A shock-resistant and leak-proof hydraulic cylinder, comprising a cylinder barrel (1), a piston rod (2), a base (101), and a top cover (102), wherein the cylinder barrel (1) is respectively fitted with a base (101) and a top cover (102) at both ends, forming a closed cavity inside the cylinder barrel (1), wherein a piston (3) connected to the piston rod (2) is provided inside the cavity, and the piston rod (2) extends out from the top cover (102), characterized in that: The piston (3) divides the cavity in the cylinder (1) into two non-communicating cavities. The piston (3) and the base (101) form a rodless cavity (11), and the piston (3) and the top cover (102) form a rod cavity (12). A sealing element is provided between the piston (3) and the inner wall of the cylinder (1), and an annular groove (35) is provided on the contact surface between the piston (3) and the inner wall of the cylinder (1). The annular groove (35) is located on the side of the sealing element close to the rod cavity (12). A pressure relief hole (351) is provided on the side of the piston (3) facing the rod cavity (12). The pressure relief hole (351) is connected to the rod cavity (12), and the annular groove (35) and the pressure relief hole (351) are connected.

2. The anti-vibration and leak-proof hydraulic cylinder according to claim 1, characterized in that: The piston rod (2) is located inside the cylinder (1) at one end as piston rod end (21). The piston rod end (21) passes through the piston (3). The piston rod end (21) is machined with external threads and is connected and fixed to the piston (3) by locking nut (31), so that the piston (3) and piston rod (2) can move synchronously.

3. The anti-vibration and leak-proof hydraulic cylinder according to claim 1, characterized in that: At least one pressure relief hole (351) is provided and is formed by drilling. A flow channel is provided between the pressure relief hole (351) and the annular groove (35). The flow channel connects the annular groove (35) and the pressure relief hole (351). At the same time, the diameter of the flow channel is smaller than the diameter of the pressure relief hole (351) and the width of the annular groove (35).

4. The anti-vibration and leak-proof hydraulic cylinder according to claim 3, characterized in that: The seal includes a wear-resistant ring (32) and a piston seal (33), and the piston seal (33) has a wear-resistant ring (32) on the side near the rodless chamber (11) and the side near the rod chamber (12).

5. The anti-vibration and leak-proof hydraulic cylinder according to claim 4, characterized in that: The piston (3) is provided with a bronze ring (34) made of bronze on the contact surface between the piston (3) and the inner wall of the cylinder (1). The bronze ring (34) is located on the side of the annular groove (35) near the rod chamber (12).

6. The anti-vibration and leak-proof hydraulic cylinder according to claim 4, characterized in that: Two annular grooves (35) are provided, and they are connected to the pressure relief hole (351) through a flow channel. The annular grooves (35) are respectively provided on both sides of the wear ring (32) on the side of the seal near the rod chamber (12). At the same time, the two annular grooves (35) are located on the side of the piston seal (33) away from the rodless chamber (11).

7. The anti-vibration and leak-proof hydraulic cylinder according to claim 1, characterized in that: The cylinder (1) is provided with a rodless chamber port (52) and a rod chamber port (6) for injecting fluid into the rodless chamber (11) and the rod chamber (12).

8. The anti-vibration and leak-proof hydraulic cylinder according to claim 7, characterized in that: The cylinder (1) is provided with an oil port block (5), which integrates inlet and return oil circuits and control valves. The oil port block (5) is connected to the rodless chamber oil port (52) through an oil pipe (51). The oil port block (5) can be connected to the rod chamber oil port (6) through a pipeline.

9. A shock-resistant, leak-proof hydraulic cylinder according to any one of claims 1-8, characterized in that: A base earring (1011) is fixed on the base (101), and a piston rod earring (1021) is fixed on the top cover (102). The base earring (1011) and the piston rod earring (1021) are used to connect devices that move relative to each other. A radial joint bearing is provided inside the piston rod earring (1021).

10. A shock-resistant, leak-proof hydraulic cylinder according to any one of claims 1-8, characterized in that: The cylinder (1) is fitted with a sleeve (4), which is fixedly connected to the cylinder (1). A bracket (41) is provided on one side of the sleeve (4), and a base ear (1011) is provided on the bracket (41). A piston rod ear (1021) is fixed on the top cover (102). The base ear (1011) and the piston rod ear (1021) are coplanar. A radial joint bearing is provided inside the base ear (1011) and the piston rod ear (1021).

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