High-pressure large-flow heavy-load hydraulic cylinder based on pressure relief structure

Abstract

This invention relates to the field of hydraulic cylinder technology and discloses a high-pressure, high-flow, heavy-duty hydraulic cylinder based on a pressure-relief structure. The cylinder includes a cylinder barrel with a cylinder bottom and end caps installed at its left and right ends, respectively. The end caps are composed of a first combined cover and a second combined cover connected detachably. The cylinder bottom is composed of a first combined plate and a second combined plate connected detachably. Both the first and second combined covers have an oil port on their upper outer walls. This high-pressure, high-flow, heavy-duty hydraulic cylinder based on a pressure-relief structure effectively solves the problems in existing technologies where, after pressure holding, a large amount of elastic potential energy accumulates in the high-pressure cavity, and if released too quickly during pressure relief, it will generate severe hydraulic shock, causing hydraulic cylinder vibration, pipeline and component fatigue damage; under high-pressure alternating loads, the seals are subject to frequent pressure fluctuations and temperature changes, accelerating aging and wear, causing external and internal leakage; and fundamental causes such as guide wear and cylinder wall scoring are often overlooked.

Description

Technical Field

[0001] This invention relates to the field of hydraulic cylinder technology, and specifically to a high-pressure, high-flow, heavy-duty hydraulic cylinder based on a pressure relief structure. Background Technology

[0002] Heavy-duty hydraulic cylinders are core actuators in heavy-duty equipment such as forging machinery, metallurgical equipment, and construction machinery. They typically drive loads of hundreds to thousands of tons to complete reciprocating motions under high pressure and high flow conditions, and their performance directly determines the equipment's working capacity, efficiency, and safety. As heavy equipment develops towards larger tonnage, longer stroke, and higher frequency, the cylinders face stringent requirements in all stages of rapid advance, working advance, pressure holding, and reversing, including their body structure, sealing, and guiding systems.

[0003] To address this issue, this application designs a high-pressure, high-flow, heavy-duty hydraulic cylinder based on a pressure-relief structure. Existing heavy-duty hydraulic cylinders mainly suffer from two problems: First, after pressure holding, a large amount of elastic potential energy accumulates in the high-pressure cavity. If the pressure is released too quickly during depressurization, it will generate a severe hydraulic shock, causing hydraulic cylinder vibration, fatigue damage to pipelines and components, and a decrease in control accuracy. Second, under high-pressure alternating loads, the seals are subject to frequent pressure fluctuations and temperature changes, which accelerates aging and wear, causing external leakage (oil seepage, shutdown) and internal leakage (insufficient thrust, reduced pressure holding). At the same time, fundamental causes such as guide wear and cylinder wall scoring are often overlooked, leading to repeated leakage problems after seal replacement. Summary of the Invention

[0004] To address the aforementioned shortcomings of existing technologies, this invention provides a high-pressure, high-flow, heavy-duty hydraulic cylinder based on a pressure-relief structure. This effectively solves the problems in existing technologies where, after pressure holding, a large amount of elastic potential energy accumulates in the high-pressure cavity; if released too quickly during pressure relief, it generates severe hydraulic shock, causing hydraulic cylinder vibration, fatigue damage to pipelines and components, and a decrease in control accuracy. Furthermore, under high-pressure alternating loads, frequent pressure fluctuations and temperature changes accelerate the aging and wear of seals, leading to external and internal leaks. Simultaneously, fundamental causes such as guide wear and cylinder wall scoring are often overlooked, resulting in recurring leakage problems after seal replacement.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a high-pressure, high-flow, heavy-duty hydraulic cylinder based on a pressure-relief structure, comprising: The cylinder has a cylinder bottom and an end cover installed at its left and right ends respectively. The end cover is composed of a first combination cover and a second combination cover connected by a detachable connection. The cylinder bottom is composed of a first combination plate and a second combination plate connected by a detachable connection. The upper outer walls of the first combination cover and the second combination cover are both provided with oil ports. The upper outer walls of the first combination plate and the first combination plate are also both provided with oil ports. The end cover and the piston rod are both provided with sealing parts. The end cover and the cylinder bottom are both provided with pressure relief protection parts. The pressure relief protection unit includes a pressure relief chamber located at the opposite ends of combined cover one and combined cover two, and a pressure relief chamber also located at the opposite ends of combined plate one and combined plate two. The pressure relief chamber has an upward-facing C-shaped design. Several stepped holes are evenly distributed in a circle at the opposite ends of combined cover one and combined plate one. The stepped holes are connected to the corresponding pressure relief chambers. Buffer supports are symmetrically arranged on the left and right sides inside the cylinder. The buffer supports are composed of a flexible hollow disc and several integrated through-mounted guide rods. The guide rods are evenly distributed in a circle. Pressure regulating groups are provided on the end cover and the bottom of the cylinder.

[0006] Furthermore, both the first and second combination covers are hollow structures. The first combination cover consists of a hollow base and an annular connecting plate, which together form an oil cavity. The first combination plate is a hollow structure, while the second combination plate is a disc structure with a docking groove on its right end. The docking grooves on the first and second combination plates together form an oil cavity.

[0007] Furthermore, the oil ports on the end cap and the cylinder bottom are L-shaped designs with different inclination angles. The output port of the oil port on the end cap is connected to the oil cavity of the combined cover, and the output port of the oil port on the cylinder bottom is connected to the oil cavity of the combined plate. A swirling groove is provided on the inner wall of the oil cavity, and the swirling groove is a spiral design.

[0008] Furthermore, the pressure relief protection unit also includes a circular cavity located on the flexible hollow disk and the guide rod at the end away from the adjacent oil cavity. A pressure relief hole is also provided on the outer wall of the end of the guide rod away from the flexible hollow disk, and the pressure relief hole is connected to the corresponding circular cavity. A swirling groove II is provided on the inner wall of the flexible hollow disk, and the swirling groove II is designed in a spiral shape.

[0009] Furthermore, the right end of the first combination cover is located on both the inner and outer sides, and a mating block 1 is symmetrically and integrally installed on both the front and back. The left end of the second combination cover has a mating groove 1 corresponding to several mating blocks 1. The left end of the first combination plate is located on both the inner and outer sides, and a mating block 2 is symmetrically and integrally installed on both the front and back. The right end of the second combination cover has a mating groove 2 corresponding to several mating blocks 2.

[0010] Furthermore, the pressure regulating assembly includes an adjusting screw that is symmetrically rotated and installed through the end cover and the outer wall of the cylinder bottom. A flow restrictor is threadedly connected to the threaded section of the adjusting screw. The flow restrictor has a stepped structure with a conical surface. A limit slide rod is symmetrically installed at the end of the flow restrictor away from the oil cavity. The tail end of the limit slide rod has a limit plate. The opposite ends of the combined cover one and combined cover two are provided with circular limit grooves corresponding to the limit slide rods. The opposite ends of the combined plate one and combined plate two are also provided with circular limit grooves corresponding to the limit slide rods.

[0011] Furthermore, the pressure relief protection unit also includes a circular through hole located on the first combination plate and the two inner front and rear mating grooves. The end of the adjusting screw on the cylinder bottom near the oil chamber is located in the circular through hole. The inner wall of the pressure relief chamber has symmetrically arranged receiving cavities on the two inner front and rear mating blocks. The end of the adjusting screw on the end cover near the oil chamber is rotatably connected to the inner wall of the receiving cavity. The opposite ends of the first combination cover and the second combination cover are symmetrically arranged with docking channels. One end of the docking channel is connected to the oil port, and the other end is connected to the receiving cavity.

[0012] Furthermore, the sealing part includes a dustproof ring embedded on the right side of the inner wall of the second combined cover, an end sealing ring embedded on the left side of the dustproof ring on the inner wall of the second combined cover, an installation groove 1 is opened in the middle of the outer wall of the piston section of the piston rod, and installation grooves 2 are symmetrically opened on the left and right sides of the outer wall of the piston section of the piston rod. Both installation groove 1 and installation groove 2 are annular grooves with a convex cross-section, and the width of installation groove 1 is greater than the width of installation groove 2. A piston wear-resistant ring is detachably installed on the inner wall of installation groove 1, and a piston sealing ring is detachably installed on the inner wall of installation groove 2.

[0013] Furthermore, the opposite ends of the first and second combination plates are provided with exhaust holes on the lower side of the outer wall. The exhaust holes are designed in a bent shape and are connected to the internal cavity of the cylinder. An exhaust plug is installed on the inner wall of the end of the exhaust hole that is close to the outer wall of the cylinder bottom.

[0014] The technical solution provided by this invention has the following advantages compared with the prior art: This invention provides a high-pressure, high-flow, heavy-duty hydraulic cylinder based on a pressure-relief structure. During the staged pressure relief phase of the piston rod retraction stroke, the cylinder undergoes a multi-stage synergistic pressure relief process. This is achieved through a first-stage throttling and pressure reduction via a damping gap formed between the flow-limiting plug and the inner wall of the circular through-hole, followed by energy dissipation from swirling flow in swirling channels one and two, and throttling through the pressure relief orifice. Consequently, the elastic potential energy accumulated in the high-pressure oil near the cylinder bottom is smoothly converted into heat energy. This prevents hydraulic shock, pipeline vibration, and component fatigue damage during the piston rod's return stroke pressure relief, allowing the piston rod to decelerate evenly and stop gently. This effectively protects the cylinder structure and significantly improves the accuracy of pressure relief control. During the extension stroke, the multi-stage synergistic pressure relief effect of the first-stage throttling pressure reduction through the damping gap formed between the flow restrictor and the inner wall of the receiving cavity, the swirling energy consumption of the first and second swirling grooves, and the throttling of the pressure relief hole, ensures that the elastic potential energy accumulated in the high-pressure oil near the end cover in the cylinder is smoothly converted into heat energy. This avoids hydraulic shock, pipeline vibration, and component fatigue damage during piston rod extension pressure relief, allowing the piston rod to decelerate evenly and stop gently, effectively protecting the cylinder structure and significantly improving the accuracy of pressure relief control.

[0015] During the staged decompression phase of the piston rod extension stroke, as the piston rod retracts and approaches the buffer bracket, it undergoes uniform deceleration and gentle stopping until it is in close contact with the buffer bracket. The flexible hollow disc on the buffer bracket further prevents the piston rod from directly impacting the cylinder bottom during the retraction stroke, eliminating the water hammer effect, ensuring accurate positioning at the end of the return stroke, and effectively extending the mechanical life of the piston rod and the cylinder bottom. Similarly, as the piston rod extends and approaches the buffer bracket, it undergoes uniform deceleration and gentle stopping until it is in close contact with the buffer bracket. The flexible hollow disc on the buffer bracket further prevents the piston rod from directly impacting the end cap during the extension stroke, eliminating the water hammer effect, ensuring accurate positioning at the end of the extension stroke, and effectively extending the mechanical life of the piston rod and the end cap. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0017] Figure 1 This is a schematic diagram of the three-dimensional structure in an embodiment of the present invention; Figure 2 This is a schematic diagram of the three-dimensionally separated structure in an embodiment of the present invention; Figure 3 This is a schematic diagram of a partial three-dimensional cross-section of the cylinder barrel, end cap, and cylinder bottom in an embodiment of the present invention; Figure 4This is a schematic diagram of a partial three-dimensional cross-section of the piston rod in an embodiment of the present invention; Figure 5 This is a schematic diagram of a partial three-dimensional cross-section of the buffer bracket in an embodiment of the present invention; Figure 6 This is a schematic diagram of the three-dimensional separation of the combined plate 1, combined plate 2, and buffer bracket in an embodiment of the present invention; Figure 7 This is a schematic diagram of a partial three-dimensional cross-section of the combined plate 1, combined plate 2, and pressure relief protection unit in an embodiment of the present invention; Figure 8 This is a schematic diagram of the three-dimensional separation of the combined plate and the pressure relief protection part in an embodiment of the present invention; Figure 9 This is a schematic diagram of a partial three-dimensional cross-section of the combined cover one and combined cover two in an embodiment of the present invention; Figure 10 This is a schematic diagram of the three-dimensional separation of the combined cover and the pressure relief protection part in an embodiment of the present invention; Figure 11 This is a schematic diagram of the three-dimensional separation of the combined cover one, combined cover two, and buffer support in an embodiment of the present invention.

[0018] The labels in the diagram represent: 1. Cylinder; 2. End cap; 21. Combined cap one; 22. Combined cap two; 23. Mating block one; 24. Mating groove one; 3. Cylinder bottom; 31. Combined plate one; 32. Combined plate two; 33. Exhaust port; 34. Exhaust plug; 35. Mating block two; 36. Mating groove two; 4. Piston rod; 5. Oil port; 51. Oil chamber; 52. Swirl groove one; 6. Sealing part; 61. Dust seal; 62. End sealing ring; 63. Piston wear ring; 64. Piston sealing ring; 7. Pressure relief protection part; 71. Pressure relief chamber; 72. Stepped hole; 73. Buffer bracket; 731. Swirl groove II; 74. Pressure relief hole; 75. Pressure regulating group; 751. Adjusting screw; 752. Flow limiting plug; 753. Limiting slide bar; 754. Circular limiting groove; 76. Circular through hole; 77. Receiving cavity; 78. Connecting flow channel. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] The present invention will be further described below with reference to embodiments.

[0021] Example:

[0022] Please see Figures 1-11 This invention provides a technical solution: a high-pressure, high-flow, heavy-duty hydraulic cylinder based on a pressure-relief structure, comprising: Cylinder 1, cylinder bottom 3 and end cover 2 are respectively installed at the left and right ends of cylinder 1. End cover 2 is composed of combination cover 1 21 and combination cover 22 connected by a detachable connection. Cylinder bottom 3 is composed of combination plate 1 31 and combination plate 2 32 connected by a detachable connection. Oil port 5 is opened on the upper end of the outer wall of combination cover 1 21 and combination cover 22. Oil port 5 is also opened on the upper end of the outer wall of combination plate 1 31. Sealing part 6 is provided on end cover 2 and piston rod 4. Pressure relief protection part 7 is provided on end cover 2 and cylinder bottom 3. The pressure relief protection unit 7 includes a pressure relief chamber 71 located at the opposite ends of the combined cover 21 and the combined cover 22, and a pressure relief chamber 71 located at the opposite ends of the combined plate 31 and the combined plate 32. The pressure relief chamber 71 has an upward-facing C-shaped design. Several stepped holes 72 are evenly distributed in a circle at the opposite ends of the combined cover 21 and the combined plate 31. The stepped holes 72 are connected to the corresponding pressure relief chambers 71. Buffer supports 73 are symmetrically arranged on the left and right sides inside the cylinder 1. The buffer supports 73 are composed of a flexible hollow disc and several integrated through-mounted guide rods. The guide rods are evenly distributed in a circle. Pressure regulating groups 75 are provided on the end cover 2 and the cylinder bottom 3.

[0023] Both the first combination cover 21 and the second combination cover 22 are hollow structures. The first combination cover 21 consists of a hollow base and an annular connecting plate. The hollow base and the annular connecting plate together form an oil cavity 51. The first combination plate 31 is a hollow structure. The second combination plate 32 is a disc structure with a docking groove on the right end. The docking grooves on the first combination plate 31 and the second combination plate 32 together form an oil cavity 51.

[0024] The oil ports 5 on the end cap 2 and the cylinder bottom 3 are L-shaped designs with different inclination angles. The output port of the oil port 5 on the end cap 2 is connected to the oil cavity 51 of the combined cover 21, and the output port of the oil port 5 on the cylinder bottom 3 is connected to the oil cavity 51 of the combined plate 31. A swirling groove 52 is provided on the inner wall of the oil cavity 51. The swirling groove 52 is a spiral design.

[0025] The pressure relief protection unit 7 also includes a circular cavity that is opened together on the flexible hollow disk and the guide rod at the end away from the adjacent oil cavity 51. A pressure relief hole 74 is also opened on the outer wall of the end of the guide rod away from the flexible hollow disk. The pressure relief hole 74 is connected to the corresponding circular cavity. A swirl groove 731 is opened on the inner wall of the flexible hollow disk. The swirl groove 731 is a spiral design.

[0026] The right end of the first combination cover 21 is located on both the inner and outer sides, and the front and back are symmetrically and integrally installed with mating blocks 23. The left end of the second combination cover 22 is provided with mating grooves 24 corresponding to several mating blocks 23. The left end of the first combination plate 31 is located on both the inner and outer sides, and the front and back are symmetrically and integrally installed with mating blocks 35. The right end of the second combination cover 22 is provided with mating grooves 36 corresponding to several mating blocks 35.

[0027] The pressure regulating assembly 75 includes an adjusting screw 751 that is symmetrically and rotatably installed on the outer walls of the end cover 2 and the cylinder bottom 3. A flow restrictor 752 is threadedly connected to the threaded section of the adjusting screw 751. The flow restrictor 752 is a stepped structure with a conical surface. A limit slide rod 753 is symmetrically installed at the end of the flow restrictor 752 away from the oil cavity 51. The tail end of the limit slide rod 753 has a limit plate. The opposite ends of the combined cover 1 21 and combined cover 22 are provided with circular limit grooves 754 corresponding to the limit slide rod 753. The opposite ends of the combined plate 1 31 and combined plate 2 32 are also provided with circular limit grooves 754 corresponding to the limit slide rod 753.

[0028] The pressure relief protection unit 7 also includes a circular through hole 76 that is opened on the first combination plate 31 and the two inner front and rear mating grooves 36. The adjusting screw 751 on the cylinder bottom 3 is located in the circular through hole 76 at one end near the oil chamber 51. The inner wall of the pressure relief chamber 71 is provided with symmetrically arranged receiving cavities 77 corresponding to the two inner front and rear mating blocks 23. The adjusting screw 751 on the end cover 2 is rotatably connected to the inner wall of the receiving cavity 77 at one end near the oil chamber 51. The opposite ends of the first combination cover 21 and the second combination cover 22 are provided with symmetrically arranged docking channels 78. One end of the docking channel 78 is connected to the oil port 5, and the other end is connected to the receiving cavity 77.

[0029] The sealing part 6 includes a dustproof ring 61 embedded on the right side of the inner wall of the second combination cover 22, and an end sealing ring 62 embedded on the left side of the dustproof ring 61 on the inner wall of the second combination cover 22. The piston section of the piston rod 4 has a mounting groove 1 in the middle and mounting groove 2 symmetrically opened on the outer wall of the piston section of the piston rod 4. Both mounting groove 1 and mounting groove 2 are annular grooves with a convex cross-section, and the width of mounting groove 1 is greater than the width of mounting groove 2. A piston wear-resistant ring 63 is detachably installed on the inner wall of mounting groove 1, and a piston sealing ring 64 is detachably installed on the inner wall of mounting groove 2.

[0030] The opposite ends of the first combination plate 31 and the second combination plate 32 are provided with exhaust holes 33 on the lower side of the outer wall. The exhaust holes 33 are bent and are connected to the internal cavity of the cylinder 1. An exhaust plug 34 is installed on the inner wall of the end of the exhaust hole 33 that is close to the outer wall of the cylinder bottom 3.

[0031] In practice: First, the sealing part 6 in this application is used to reliably seal the high-pressure oil film between the inner wall of the cylinder 1 and the outer wall of the piston rod 4 after the high-pressure working and holding tasks are completed, through the combination of piston sealing ring 64, end sealing ring 62 and dustproof ring 61, and with the guide support of piston wear ring 63, to achieve leak-free operation under all working conditions. The pressure relief protection part 7 is used to reduce the pressure of the high-pressure oil in stages through the damping throttling channel formed by stepped hole 72, pressure relief chamber 71 and pressure regulating group 75 when the cylinder 1 needs to return after the pressure holding is completed. This avoids the piston rod 4 from vibrating and impact deformation when the high pressure is suddenly released, and ensures the smooth movement of the piston rod 4 throughout the pressure relief stroke. This achieves smooth pressure relief and buffer protection for the high-pressure, high-flow heavy-duty hydraulic cylinder, avoiding the severe hydraulic shock and component fatigue damage caused by the instantaneous release of elastic potential energy of the high-pressure cavity when the traditional heavy-duty hydraulic cylinder is released after pressure holding.

[0032] It should be noted that when the cylinder 1 needs to return after the pressure holding period in normal conditions, directly connecting the main return oil circuit will instantly release the elastic potential energy accumulated by the high-pressure oil in the cylinder 1 cavity, causing a violent hydraulic shock. In this application, the end cover 2 and the cylinder bottom 3 are both equipped with pressure regulating groups 75 and pressure relief chambers 71 with similar structures and working principles. When the piston rod 4 extends or retracts into the cylinder 1, the pressure regulating groups 75 on the end cover 2 and the cylinder bottom 3 will perform pressure relief.

[0033] During the pre-setting and debugging phase of the pressure regulating group 75, based on the current pressure holding level, load inertia, and working condition requirements of the heavy-duty hydraulic cylinder, the opening of the flow limiting plugs 752 on one side of the end cap 2 and the cylinder bottom 3 needs to be adjusted in advance to set the size of the damping gap during staged pressure relief. Specifically, the operator rotates the two adjusting screws 751 on the outer wall of the end cap 2 and the cylinder bottom 3 respectively. The threaded section of the adjusting screw 751 will drive the flow limiting plug 752 to move axially along the adjusting screw 751. During this period, the limiting slide rod 753 will perform adaptive sliding compensation limiting on the inner wall of the corresponding circular limiting groove 754 to ensure that the flow limiting plug 752 does not deflect circumferentially. When the flow limiting plug 752 is pushed towards the oil cavity 51, the damping gap between its conical surface and the wall of the pressure relief cavity 71 gradually decreases, and the pressure relief and throttling effect is enhanced, which is suitable for heavy forging scenarios with high pressure holding and slow pressure relief. When the flow limiting plug 752 is pulled away from the oil cavity 51, As the damping gap gradually increases, the pressure relief and throttling effect weakens. This design is suitable for scenarios requiring rapid and stable pressure relief under moderate holding pressure. For the cylinder bottom 3 sides, a precision damping gap is formed between the conical surface of the flow-limiting plug 752 and the inner wall of the circular through hole 76. For the end cap 2 sides, a precision damping gap is formed between the conical surface of the flow-limiting plug 752 and the inner wall of the receiving cavity 77. The pressure adjustment groups 75 on the end cap 2 and the cylinder bottom 3 can be independently set to different opening degrees to adapt to the pressure relief requirements in different directions when the piston rod 4 extends and retracts. When the adjustment is in place, the self-locking thread of the adjusting screw 751 can keep the position of the flow-limiting plug 752 constant. Through the independent preset of the pressure adjustment groups 75 at both ends, the pressure relief damping gap can be accurately calibrated, providing throttling characteristics that match the working conditions for subsequent staged pressure relief. This ensures that the pressure relief process is neither too fast and causes impact, nor too slow and affects work efficiency, so that the heavy-duty hydraulic cylinder can achieve the optimal pressure relief effect under different holding pressure and load conditions.

[0034] During the initial start-up and exhaust phase, the exhaust plugs 34 on the first combination plate 31 and the second combination plate 32 must be opened first, and low-pressure oil is injected into the cylinder 1 through the oil port 5. The oil flows through the oil chamber 51 at the first combination plate 31, and is guided by the spiral swirl groove 52 to form an orderly swirling flow before filling the inner cavity of the cylinder 1. This pushes the air in the cylinder 1 to be discharged from the exhaust port 33 until oil is continuously discharged. Then, the exhaust plug 34 is locked. At this time, the piston rod 4 is in the retracted state, and the piston end of the piston rod 4 is in contact with the buffer bracket 73 on the left side. Several guide rods on the buffer bracket 73 are fully inserted into the stepped hole 72. The pressure relief hole 74 on the guide rod will be connected to the corresponding pressure relief chamber 71. The residual air in the cylinder 1 is completely discharged through the exhaust plug 34, which effectively prevents crawling and vibration caused by cavitation and provides a reliable guarantee for the smooth extension and retraction of the piston rod 4 along the inner wall of the cylinder 1.

[0035] During the rapid feed phase, the external reversing valve needs to be switched to the low-pressure, high-flow oil supply position. The pressurized oil will enter the oil chamber 51 from the oil port 5 on the bottom of the cylinder 3. At this time, the pressurized oil will be rectified by the spiral swirl channel 52 and then smoothly fill the inner cavity of the cylinder 1, pushing the piston rod 4 to extend rapidly. During this period, the oil on the other side of the inner cavity of the cylinder 1 needs to be gradually discharged back to the oil tank through the oil chamber 51 and oil port 5 on the end cover 2. At this time, several guide rods on the buffer bracket 73 will also extend into the inner side of the cylinder 1 from the corresponding stepped hole 72. The pressure relief hole 74 on the guide rod will be blocked by the inner wall of the corresponding stepped hole 72, disconnecting the connection with the corresponding pressure relief chamber 71. The swirl channel 52 in the oil chamber 51 effectively suppresses the flow channel impact and pressure pulsation, and together with the large-diameter oil port 5, the piston rod 4 can be fed with low resistance and rapid feed.

[0036] When the piston rod 4 comes into contact with the workpiece under load, the pressure oil will switch to high-pressure, low-flow oil supply. At this time, the pressure inside the cylinder 1 will rise, and the piston seal ring 64 in the mounting groove 2 on the piston section of the piston rod 4 will also expand under pressure, forming a high-pressure seal against the inner wall of the cylinder 1. The piston wear-resistant ring 63 in the mounting groove 1 can withstand lateral guide loads and prevent direct metal-to-metal contact. The end seal ring 62 embedded in the end cap 2 is used to prevent oil leakage. The dust ring 61 scrapes away impurities on the surface of the piston rod 4. Through the synergistic effect of multiple seals and wear-resistant guide structures, the piston rod 4 can stably withstand heavy-load alternating pressure, eliminate external and internal leakage, ensure stable thrust output, and extend the service life of the seals and cylinder 1.

[0037] During the pressure holding phase, after the piston rod 4 reaches the feed set position, the external control directional valve maintains a stable state, sealing the oil ports 5 on the end cover 2 and cylinder bottom 3. The high-pressure oil in the cylinder 1 stably seals the connection surface between the end cover 2 and cylinder bottom 3. It is worth emphasizing that the buffer bracket 73 on one side of the cylinder bottom 3 will be at its maximum stroke extending inward into the cylinder 1, and the pressure relief hole 74 on the guide rod will be blocked by the inner wall of the corresponding stepped hole 72, disconnecting the communication with the corresponding pressure relief chamber 71. The buffer bracket 73 on one side of the end cover 2 will be at its maximum retraction away from the cylinder 1. During the stroke, the pressure relief hole 74 on the guide rod will disengage from the inner wall of the corresponding stepped hole 72, restoring the connection with the corresponding pressure relief chamber 71. The flow limiting plug 752 in the pressure regulating group 75 on one side of the end cover 2 will be inserted into the corresponding receiving chamber 77 at the preset micro-opening of the corresponding regulating screw 751, forming only a tiny throttling gap, which does not affect the pressure holding effect. Through the combination of precision throttling compensation and long-term sealing symmetrically set on the end cover 2 and the cylinder bottom 3, long-term stable pressure holding can be achieved, eliminating the risk of workpiece loosening caused by pressure decay, and ensuring safe and reliable heavy-duty clamping.

[0038] During the staged pressure relief phase of the piston rod 4 retraction stroke, when the piston rod 4 needs to retract into the cylinder 1 after the pressure holding period, directly connecting the main return oil circuit will instantly release the elastic potential energy accumulated in the high-pressure oil inside the cylinder 1, causing a violent hydraulic shock. After the pilot stage of the directional valve or the main valve core of the control peripheral moves slightly, the high-pressure oil on both sides of the piston section of the piston rod 4 in the cylinder 1 will gradually flow into the oil chamber 51 on the side of the cylinder bottom 3, and be discharged back into the oil tank through the oil port 5 on the cylinder bottom 3. During this period, the high-pressure oil on the side of the cylinder bottom 3 is gradually discharged, and the high-pressure oil on the side of the end cap 2 is gradually filled. When the high-pressure oil flows through the oil chamber 51 on the cylinder bottom 3, the spiral swirling groove 52 on its inner wall can force the high-pressure oil to generate a rotating vortex. During this period, the high-pressure oil inside the cylinder 1 will exert pressure on the buffer support 73 on the side of the cylinder bottom 3, pushing it to move towards the side of the cylinder bottom 3 until it slowly... Several guide rods on the piston rod 73 are fully inserted into the stepped hole 72. At this time, the buffer support 73 on one side of the cylinder bottom 3 will be in its maximum stroke, retracting away from the cylinder barrel 1. The flexible hollow disc of the buffer support 73 will fit tightly against the combined plate 31, and the pressure relief hole 74 on the guide rod will also detach from the inner wall of the corresponding stepped hole 72 and insert into the corresponding pressure relief chamber 71, restoring the communication effect with the corresponding pressure relief chamber 71. It is worth emphasizing that when the piston rod 4 retracts and approaches the buffer support 73, it will undergo uniform deceleration and gentle stopping until it fits tightly against the buffer support 73. The flexible hollow disc on the buffer support 73 can further prevent the piston rod 4 from directly impacting the cylinder bottom 3 during the retraction stroke, eliminating the water hammer effect, ensuring accurate positioning at the end of the return stroke, and effectively extending the mechanical life of the piston rod 4 and the cylinder bottom 3.

[0039] When the pressure relief hole 74 is connected to the corresponding pressure relief chamber 71, some of the high-pressure oil in the cylinder 1 will pass through several circular cavities on the buffer support 73 on one side of the cylinder bottom 3, sequentially through the corresponding pressure relief hole 74, and then into the pressure relief chamber 71 on the cylinder bottom 3. Since the two front and rear adjusting screws 751 on the cylinder bottom 3 have been pre-rotated to a slightly open position, a damping gap is formed between the tapered flow restrictor 752 and the inner wall of the circular through hole 76. The high-pressure oil will pass through this gap to achieve a first-stage throttling and pressure reduction before entering the oil chamber 51 on the cylinder bottom 3, and then follow the main flow of high-pressure oil through the oil port 5 on the cylinder bottom 3 back to the oil tank. In addition, when the high-pressure oil flows through the flexible hollow disc of the buffer support 73, the spiral swirling groove 2 731 on its inner wall, in conjunction with the swirling groove 1 52 on the cylinder bottom 3, can force... The high-pressure oil is made to generate a rotating vortex, and the energy is dissipated through fluid friction to achieve secondary vortex energy dissipation. At the same time, when the high-pressure oil flows through the pressure relief hole 74 on the guide rod, the sudden change in the flow channel cross section creates local resistance, which can achieve tertiary throttling damping. After the first-level throttling pressure reduction through the damping gap formed between the flow limiting plug 752 and the inner wall of the circular through hole 76, the vortex energy dissipation of vortex groove 1 52 and vortex groove 2 731, and the throttling effect of the pressure relief hole 74, the elastic potential energy accumulated in the high-pressure oil near the bottom 3 of the cylinder 1 will be smoothly converted into heat energy, avoiding hydraulic shock, pipeline vibration and component fatigue damage during the return pressure relief of the piston rod 4, so that the piston rod 4 decelerates evenly and stops gently, effectively protecting the cylinder structure and greatly improving the pressure relief control accuracy.

[0040] During the staged pressure relief phase of the piston rod 4 extension stroke, when the piston rod 4 needs to extend out of the cylinder 1, directly connecting the main return oil circuit will also instantly release the elastic potential energy accumulated in the high-pressure oil inside the cylinder 1, causing a violent hydraulic shock. After the pilot stage of the directional valve or the main valve core of the control peripheral is slightly moved, the high-pressure oil on both sides of the piston section of the piston rod 4 in the cylinder 1 will gradually flow into the oil chamber 51 on the end cover 2 side, and be discharged back to the oil tank through the oil port 5 on the end cover 2. During this period, the high-pressure oil on the end cover 2 side is gradually discharged, and the high-pressure oil on the cylinder bottom 3 side is gradually filled. When the high-pressure oil flows through the oil chamber 51 on the end cover 2, the spiral vortex groove 52 on its inner wall can force the high-pressure oil to generate a rotating vortex. During this period, the high-pressure oil inside the cylinder 1 will exert pressure on the buffer bracket 73 on the end cover 2 side, pushing it to move towards the end cover 2 side until it slowly... Several guide rods on the piston rod 73 are fully inserted into the stepped hole 72. At this time, the buffer support 73 on one side of the end cover 2 will be in its maximum stroke, retracting away from the cylinder 1. The flexible hollow disc of the buffer support 73 will fit tightly against the combined cover 21, and the pressure relief hole 74 on the guide rod will also detach from the inner wall of the corresponding stepped hole 72 and insert into the corresponding pressure relief chamber 71, restoring the communication effect with the corresponding pressure relief chamber 71. It is worth emphasizing that when the piston rod 4 extends and approaches the buffer support 73, it will be uniformly decelerated and gently stopped until it fits tightly against the buffer support 73. The flexible hollow disc on the buffer support 73 can further avoid the rigid impact that will occur between the piston rod 4 and the end cover 2 during the extension stroke, eliminate the water hammer effect, ensure accurate positioning of the extension end point, and effectively extend the mechanical life of the piston rod 4 and the end cover 2.

[0041] When the pressure relief hole 74 on the side of end cap 2 is connected to the corresponding pressure relief chamber 71, some of the high-pressure oil in cylinder 1 will pass through several circular cavities on the buffer bracket 73 on one side of end cap 2, sequentially through the corresponding pressure relief hole 74, and then into the pressure relief chamber 71 on end cap 2. Since the front and rear adjusting screws 751 on end cap 2 have been pre-rotated to a slightly open position, a damping gap is formed between the tapered flow restrictor 752 and the inner wall of the receiving cavity 77. The high-pressure oil will pass through this gap to achieve a first-stage throttling and pressure reduction before entering the docking flow channel 78 on end cap 2. Then, it will pass through the front and rear docking flow channels 78 and enter the oil chamber 51 on end cap 2, and follow the main flow of high-pressure oil through the oil port 5 on end cap 2 back to the oil tank. In addition, when the high-pressure oil flows through the flexible hollow disc of the buffer bracket 73, the spiral swirling grooves on its inner wall... The swirling groove 52 on the end cap 2, combined with the 731, forces the high-pressure oil to generate a rotating vortex. Energy is dissipated through fluid friction, achieving secondary swirling energy dissipation. Simultaneously, when the high-pressure oil flows through the pressure relief hole 74 on the guide rod, the sudden change in the flow channel cross-section creates local resistance, achieving tertiary throttling damping. Through the first-stage throttling pressure reduction formed by the damping gap between the flow limiting plug 752 and the inner wall of the receiving cavity 77, the swirling energy dissipation of the swirling groove 52 and the second swirling groove 731, and the throttling effect of the pressure relief hole 74, the elastic potential energy accumulated in the high-pressure oil near the end cap 2 in the cylinder 1 is smoothly converted into heat energy. This avoids hydraulic shock, pipeline vibration, and component fatigue damage during the piston rod 4 extension pressure relief, allowing the piston rod 4 to decelerate evenly and stop gently, effectively protecting the cylinder structure and significantly improving the pressure relief control accuracy.

[0042] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-pressure, high-flow, heavy-duty hydraulic cylinder based on a pressure-relief structure, characterized in that, include: Cylinder (1), cylinder bottom (3) and end cover (2) are installed on the left and right ends respectively. End cover (2) is composed of combination cover one (21) and combination cover two (22) connected by a detachable connection. Cylinder bottom (3) is composed of combination plate one (31) and combination plate two (32) connected by a detachable connection. Oil port (5) is opened on the upper part of the outer wall of combination cover one (21) and combination cover two (22). Oil port (5) is also opened on the upper part of the outer wall of combination plate one (31) and combination plate one (31). Sealing part (6) is provided on end cover (2) and piston rod (4). Pressure relief protection part (7) is provided on end cover (2) and cylinder bottom (3). The pressure relief protection unit (7) includes a pressure relief chamber (71) located at the opposite ends of the combined cover one (21) and combined cover two (22), and a pressure relief chamber (71) also located at the opposite ends of the combined plate one (31) and combined plate two (32). The pressure relief chamber (71) is a C-shaped design with the opening facing upward. Several stepped holes (72) are evenly distributed in a circle at the opposite ends of the combined cover one (21) and combined plate one (31). The stepped holes (72) are connected to the corresponding pressure relief chamber (71). Buffer brackets (73) are symmetrically arranged on the left and right sides inside the cylinder (1). The buffer brackets (73) are composed of a flexible hollow disc and several integrated through-mounted guide rods. The several guide rods are evenly distributed in a circle. Pressure regulating groups (75) are provided on the end cover (2) and the cylinder bottom (3).

2. The high-pressure, high-flow, heavy-duty hydraulic cylinder based on a pressure-relief structure according to claim 1, characterized in that: Both the first (21) and the second (22) of the combined cover are hollow structures. The first (21) of the combined cover consists of a hollow seat and an annular connecting plate. The hollow seat and the annular connecting plate together form an oil cavity (51). The first (31) of the combined plate is a hollow structure. The second (32) of the combined plate is a disc structure with a docking groove on the right end. The docking grooves on the first (31) and the second (32) of the combined plate together form an oil cavity (51).

3. A high-pressure, high-flow, heavy-duty hydraulic cylinder based on a pressure-relief structure according to claim 2, characterized in that: The oil ports (5) on the end cap (2) and the cylinder bottom (3) are L-shaped designs with different inclination angles. The output port of the oil port (5) on the end cap (2) is connected to the oil cavity (51) of the combined cover (21). The output port of the oil port (5) on the cylinder bottom (3) is connected to the oil cavity (51) of the combined plate (31). A swirling groove (52) is provided on the inner wall of the oil cavity (51). The swirling groove (52) is a spiral design.

4. A high-pressure, high-flow, heavy-duty hydraulic cylinder based on a pressure-relief structure according to claim 2, characterized in that: The pressure relief protection unit (7) also includes a circular cavity located on the flexible hollow disk and the guide rod at the end away from the adjacent oil cavity (51). A pressure relief hole (74) is also provided on the outer wall of the end of the guide rod away from the flexible hollow disk. The pressure relief hole (74) is connected to the corresponding circular cavity. A vortex groove (731) is provided on the inner wall of the flexible hollow disk. The vortex groove (731) is a spiral design.

5. A high-pressure, high-flow, heavy-duty hydraulic cylinder based on a pressure-relief structure according to claim 2, characterized in that: The right end of the first combined cover (21) is located on both the inner and outer sides, and the front and back are symmetrically integrated with the first mating block (23). The left end of the second combined cover (22) is provided with mating grooves (24) corresponding to several mating blocks (23). The left end of the first combined plate (31) is located on both the inner and outer sides, and the front and back are symmetrically integrated with the second mating block (35). The right end of the second combined cover (22) is provided with mating grooves (36) corresponding to several mating blocks (35).

6. A high-pressure, high-flow, heavy-duty hydraulic cylinder based on a pressure-relief structure according to claim 1, characterized in that: The pressure regulating group (75) includes an adjusting screw (751) that is symmetrically rotated and installed on the outer wall of the end cover (2) and the cylinder bottom (3). A flow restrictor (752) is threadedly connected to the threaded section of the adjusting screw (751). The flow restrictor (752) is a stepped structure with a conical surface. A limit slide rod (753) is symmetrically installed at the end of the flow restrictor (752) away from the oil cavity (51). The tail end of the limit slide rod (753) is equipped with a limit plate. The corresponding limit slide rod (753) at the opposite ends of the combined cover one (21) and combined cover two (22) is provided with a circular limit groove (754). The corresponding limit slide rod (753) at the opposite ends of the combined plate one (31) and combined plate two (32) is also provided with a circular limit groove (754).

7. A high-pressure, high-flow, heavy-duty hydraulic cylinder based on a pressure-relief structure according to claim 6, characterized in that: The pressure relief protection part (7) also includes a circular through hole (76) that is opened on the first (31) of the combination plate and the two mating grooves (36) on the inner side. The adjusting screw (751) on the cylinder bottom (3) is located in the circular through hole (76) at one end near the oil cavity (51). The two mating blocks (23) on the inner side of the pressure relief cavity (71) are symmetrically provided with a receiving cavity (77). The adjusting screw (751) on the end cover (2) is rotatably connected to the inner wall of the receiving cavity (77) at one end near the oil cavity (51). The first (21) of the combination cover and the second (22) of the combination cover are symmetrically provided with a docking channel (78) at the opposite ends. One end of the docking channel (78) is connected to the oil port (5), and the other end is connected to the receiving cavity (77).

8. A high-pressure, high-flow, heavy-duty hydraulic cylinder based on a pressure-relief structure according to claim 1, characterized in that: The sealing part (6) includes a dustproof ring (61) embedded on the right side of the inner wall of the second combination cover (22), and an end sealing ring (62) embedded on the left side of the dustproof ring (61) on the inner wall of the second combination cover (22). An installation groove 1 is provided in the middle of the outer wall of the piston section of the piston rod (4), and an installation groove 2 is provided symmetrically on the left and right sides of the outer wall of the piston section of the piston rod (4). Both the first and second installation grooves are designed as annular grooves with a convex cross-section, and the width of the first installation groove is greater than the width of the second installation groove. A piston wear-resistant ring (63) can be detachably installed on the inner wall of the first installation groove, and a piston sealing ring (64) can be detachably installed on the inner wall of the second installation groove.

9. A high-pressure, high-flow, heavy-duty hydraulic cylinder based on a pressure-relief structure according to claim 1, characterized in that: The opposite ends of the first (31) and the second (32) of the combined plate are located on the lower side of the outer wall and have an exhaust hole (33). The exhaust hole (33) is designed in a bent shape and is connected to the internal cavity of the cylinder (1). An exhaust plug (34) is installed on the inner wall of the end of the exhaust hole (33) near the outer wall of the cylinder bottom (3).

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