Large hydraulic cylinder piston rod pressure reduction sealing device

Abstract

The utility model relates to the technical field of hydraulic equipment sealing, and discloses a large hydraulic cylinder piston rod pressure reduction sealing device which comprises an inner sealing set and an outer sealing set, the inner sealing set is composed of a V-shaped combined sealing ring, a copper sleeve and an FI guide ring, and the outer sealing set is composed of a step seal and a dustproof ring. And a leaked oil collecting tank is arranged between the inner sealing group and the outer sealing group and is communicated with the oil tank through an oil backflow pressure reducing opening. Dynamic sealing is formed through the inner sealing set and a piston rod surface oil film, and the service life of the cylinder body is effectively prolonged; when the inner sealing group is abraded, the inner sealing group can be fastened through a gland screw, so that the V-shaped combined sealing ring forms dynamic sealing again; when the inner sealing group leaks, leaked oil is collected by the leaked oil collecting groove and discharged back to the oil tank through the oil backflow pressure reducing opening, so that the outer sealing group and the production environment are protected, and the problems of long shutdown maintenance time, high cost, environmental pollution and the like caused by sealing leakage of an existing large hydraulic cylinder are effectively solved.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic equipment sealing technology, and in particular to a pressure relief sealing device for a large hydraulic cylinder piston rod. Background Technology

[0002] Currently, the side cylinder of a 30MN hydraulic press used in the production of large hydraulic cylinders for metal extrusion presses has dimensions of φ320mm / φ220mm×1700mm. In existing metal extrusion press hydraulic cylinders, the cylinder body and piston rod are connected by three PTFE-filled guide strips to bear the cylinder pressure, with two step seals providing sealing. During production, if the guide strips wear out, and the first step seal experiences slight wear, the cylinder pressure is transmitted to the second step seal, which then breaks. This leads to frequent dynamic seal leakage or seepage at the cylinder head. Once hydraulic oil leakage occurs at the cylinder head, the hydraulic press must be shut down for maintenance, affecting or damaging the piston rod. The maintenance is time-consuming, wasteful of energy and media, and pollutes the environment. Furthermore, maintenance requires complex technical methods and a complete set of sealing spare parts, increasing the overall equipment operating cost. In view of these reasons, a pressure-reducing and sealing device for the piston rod of a large hydraulic cylinder is proposed. Utility Model Content

[0003] This invention aims to solve the problem that the sealing system of hydraulic cylinders in existing metal extrusion presses is prone to sealing failure and leakage due to wear of the guide belt and step seal. It provides a large hydraulic cylinder piston rod pressure reducing and sealing device. Through the double sealing structure design of the inner sealing group and the outer sealing group, combined with the setting of the seepage collection groove and the oil return pressure reducing port, the sealing performance and service life of the hydraulic cylinder are significantly improved.

[0004] To achieve the above objectives, this utility model adopts the following technical solution: a large hydraulic cylinder piston rod pressure reducing and sealing device, which comprises: a cylinder body, an O-ring, a cylinder head flange, a gland groove, a V-type combined sealing ring groove, a copper sleeve groove, flange bolts, a piston rod, a dustproof ring, a V-type combined sealing ring, a copper sleeve, an FI guide ring, an adjusting shim, a step seal, gland bolts, a gland, a dustproof groove, a step seal groove, an FI guide groove, an oil seepage collection groove, and an oil return pressure reducing port; a piston rod is installed in the cylinder body, and a piston is installed at the end of the piston rod; a hydraulic chamber is reserved between the cylinder body and the piston rod, and hydraulic oil is installed in the hydraulic chamber; a cylinder head flange is installed in the cylinder mouth of the cylinder body, and the cylinder head flange is divided into two sections, one section of the cylinder head flange is a flange plate, and the other section of the cylinder head flange is a cylinder head inner sleeve; two O-ring grooves are reserved on the outer side of the cylinder head inner sleeve, and an O-ring is installed between the O-ring groove of the cylinder head inner sleeve and the cylinder body; flange bolts are evenly distributed between the flange plate and the cylinder mouth wall of the cylinder body.

[0005] As a further description of the above technical solution:

[0006] A piston rod is installed in the cylinder head flange. A gland, a V-shaped combination seal ring, and a copper sleeve are installed between the cylinder head flange and the piston rod, respectively. Three annular grooves are reserved in the stepped segment of the cylinder head flange. The three annular grooves are respectively set as gland grooves, V-shaped combination seal ring grooves, and copper sleeve grooves. A gland is installed in the gland groove, a V-shaped combination seal ring is installed in the V-shaped combination seal ring groove, and a copper sleeve is installed in the copper sleeve groove.

[0007] As a further description of the above technical solution:

[0008] A piston rod is installed in the gland, and a dustproof ring, a step seal, and an FI guide ring are respectively installed between the gland and the piston rod. A dustproof groove, a step seal groove, an oil seepage collection groove, and an FI guide groove are reserved in sequence on the inner side of the gland. An oil return pressure relief port is reserved through one side of the gland wall and the oil seepage collection groove. A dustproof ring is installed in the dustproof groove, a step seal is installed in the step seal groove, and an FI guide ring is installed in the FI guide groove. Gland screws are evenly distributed between the edge of the gland body and the cylinder head flange. An adjusting shim is installed between one side of the gland and the platform of the gland groove. The V-type combined sealing ring, copper sleeve, and FI guide ring are set as the inner sealing group, the step seal and dustproof ring are set as the outer sealing group, the oil seepage collection groove and the oil return pressure relief port are set as the pressure relief buffer channel, and a return pipe is set between the oil return pressure relief port and the oil tank.

[0009] Working principle: During production, when hydraulic oil is continuously pressurized in the cylinder, it pushes the piston, causing the piston rod to move inward. Simultaneously, the hydraulic oil in the cylinder is sealed by a copper sleeve and a V-shaped combination seal ring. With repeated long-term operation, hydraulic oil adheres to the piston rod surface, forming an oil film. Initially, the friction between the piston rod and the copper sleeve and V-shaped combination seal ring creates a stable, small break-in gap. The oil film on the piston rod compensates for this gap. The oil film reduces friction through lubrication, forming a dynamic seal between the oil film on the piston rod and the gap between the copper sleeve and the V-shaped combination seal ring. This dynamic seal represents a stable sealing state under pressure within the cylinder. The dynamic seal increases the service life of the cylinder by more than 50%.

[0010] When the piston rod operates for a long time, and the frictional clearance between the piston rod and the copper sleeve and V-type combination seal ring wears and expands during the initial operation, it is manually tightened by the pressure cap screw. The FI guide ring squeezes the V-type combination seal ring, and the squeezed V-type combination seal ring expands inward and the inner hole shrinks. The gap between the inner hole of the V-type combination seal ring and the piston rod shrinks, and the oil film of the piston rod and the V-type combination seal ring recombine to form a dynamic seal. The dynamic seal further improves the cylinder service life by more than 30%.

[0011] During long-term operation of the piston rod in the cylinder, when the frictional clearance between the piston rod and the copper sleeve and V-type combined seal ring wears and expands again, the increased gap between the piston rod and the V-type combined seal ring causes oil to leak outwards, preventing the dynamic seal from forming. The leaked oil enters the seepage collection tank for collection and is discharged into the oil tank through the oil return pressure relief port. At the same time, the oil leaking in the cylinder is sealed by the step seal and dust ring of the outer sealing assembly, preventing oil leakage from the gland, and the step seal and dust ring are in a complete sealing state.

[0012] When oil backflow into the oil tank occurs continuously during cylinder operation, the cylinder needs to be shut down for maintenance. During cylinder maintenance, all gland screws on the gland are manually removed, the piston rod and its inner and outer sealing assemblies are manually removed, the copper sleeve and V-shaped combination seal ring are replaced, and the cylinder is restored and repaired on the outside. After cylinder maintenance, the above production operation state is resumed.

[0013] Beneficial Effects: This utility model features a double-seal structure consisting of an inner sealing group and an outer sealing group. It employs a combination of combined sealing and step seals, with an oil leakage collection groove designed between the two seals to protect the outer sealing group of the second seal. A dynamic seal is formed between the oil film on the piston rod and the gap between the copper sleeve and the V-shaped combined sealing ring. This dynamic seal increases the cylinder's service life by over 50%. When the frictional gap between the piston rod and the copper sleeve and V-shaped combined sealing ring wears and widens, manual tightening via the pressure cap screws causes the FI guide ring to compress the V-shaped combined sealing ring. The compressed V-shaped ring's inner hole shrinks, reforming the dynamic seal and further increasing the cylinder's service life by over 30%. When the first V-shaped combined sealing ring leaks or seeps oil, the seepage is collected in the oil leakage collection groove and flows directly back into the oil tank through the oil return pressure relief port. No pressure is generated between the two seals, effectively protecting the step seal of the outer sealing group. The step seal provides continuous sealing, effectively preventing cylinder head leakage, protecting the production environment, increasing the service life of large hydraulic cylinders, and reducing maintenance frequency. Attached Figure Description

[0014] The present invention will be further described below with reference to the accompanying drawings:

[0015] Figure 1 This is a schematic diagram of the overall assembly structure of this utility model;

[0016] Figure 2 yes Figure 1 A partial structural diagram;

[0017] Figure 3 yes Figure 2 A partial structural diagram;

[0018] Figure 4 yes Figure 1A partial structural diagram of the cylinder head flange;

[0019] Figure 5 yes Figure 1 A schematic diagram of a partial structure of the pressure cap;

[0020] Figure 1 , 2 1. Cylinder body 2. O-ring 3. Cylinder head flange 4. Gland groove 3-1. V-type combination seal groove 3-2. Copper sleeve groove 3-3. Flange bolt 5. Piston rod 6. Dustproof ring 7. V-type combination seal 8. Copper sleeve 9. FI guide ring 10. Adjusting shim 11. Step seal 12. Gland bolt 13. Gland 13. Dustproof groove 13-1. Step seal groove 13-2. FI guide groove 13-3. Oil seepage collection groove 14. Oil return pressure reducing port 15. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0022] The large hydraulic cylinder piston rod pressure reducing and sealing device of this utility model, such as Figure 1-5 As shown, it is installed at the cylinder port of cylinder 1;

[0023] A piston rod 5 is installed in the cylinder body 1, and a piston is installed at the end of the piston rod 5. A hydraulic chamber is reserved between the cavity of the cylinder body 1 and the piston rod 5, and hydraulic oil is installed in the hydraulic chamber. A cylinder head flange 3 is installed in the cylinder port of the cylinder body 1. The cylinder head flange 3 is divided into two sections. One section of the cylinder head flange 3 is a flange, and the other section of the cylinder head flange 3 is a cylinder head inner sleeve. Two O-rings are reserved on the outside of the cylinder head inner sleeve. An O-ring 2 is installed between the O-ring of the cylinder head inner sleeve and the cylinder body 1. Flange bolts 4 are evenly distributed between the flange and the cylinder port wall of the cylinder body 1.

[0024] A piston rod 5 is installed in the cylinder head flange 3. A gland 13, a V-shaped combined sealing ring 7, and a copper sleeve 8 are respectively installed between the cylinder head flange 3 and the piston rod 5. Three annular grooves are reserved in the cylinder head flange 3 in a stepped segment. The three annular grooves are respectively set as gland groove 3-1, V-shaped combined sealing ring groove 3-2, and copper sleeve groove 3-3. A gland 13 is installed in gland groove 3-1, a V-shaped combined sealing ring 7 is installed in V-shaped combined sealing ring groove 3-2, and a copper sleeve 8 is installed in copper sleeve groove 3-3.

[0025] A piston rod 5 is installed in the gland 13. A dustproof ring 6, a step seal 11, and an FI guide ring 9 are respectively installed between the gland 13 and the piston rod 5. A dustproof groove 13-1, a step seal groove 13-2, an oil seepage collection groove 14, and an FI guide groove 13-3 are respectively reserved on the inner side of the gland 13. An oil return pressure relief port 15 is reserved between one side of the wall of the gland 13 and the oil seepage collection groove 14. A dustproof ring 6 is installed in the dustproof groove 13-1, a step seal 11 is installed in the step seal groove 13-2, and an FI guide groove is installed in the FI guide groove. In section 13-3, a FI guide ring 9 is installed. The cover screws 12 are evenly distributed between the edge of the cover body of the cover 13 and the cylinder head flange 3. An adjusting shim 10 is installed between one side of the cover 13 and the platform of the cover groove 3-1. The V-type combined sealing ring 7, copper sleeve 8, and FI guide ring 9 are set as the inner sealing group. The step seal 11 and dustproof ring 6 are set as the outer sealing group. The oil seepage collection tank 14 and the oil return pressure reducing port 15 are set as the pressure relief buffer channel. A return pipe is set between the oil return pressure reducing port 15 and the oil tank.

[0026] The sealing device of this utility model adopts a dual sealing structure of an inner sealing group and an outer sealing group. The inner sealing group consists of a V-shaped combined sealing ring 7, a copper sleeve 8, and a FI guide ring 9, while the outer sealing group consists of a step seal 11 and a dustproof ring 6. The inner sealing group is mainly used to withstand the high-pressure hydraulic oil in the hydraulic chamber and forms a dynamic seal with the piston rod 5 surface through the V-shaped combined sealing ring 7. The outer sealing group is used to block dust and impurities in the external environment and prevent the hydraulic oil leaking from the inner sealing group from overflowing.

[0027] Furthermore, the oil leakage collection tank 14 and the oil return pressure reducing port 15 together form a pressure relief buffer channel. When the inner sealing assembly leaks, the hydraulic oil will enter the oil return pressure reducing port 15 through the oil leakage collection tank 14 and return to the oil tank through the return pipe, thereby preventing the hydraulic oil from polluting the external environment and protecting the normal operation of the outer sealing assembly.

[0028] Through the above structural design, this utility model can effectively solve the problems of easy leakage, high maintenance frequency and serious environmental pollution in the hydraulic cylinder sealing system in the prior art, significantly improve the service life of the hydraulic cylinder, reduce maintenance costs and protect the production environment.

Claims

1. A large hydraulic cylinder piston rod pressure reducing and sealing device, comprising: cylinder body (1), O-ring (2), cylinder head flange (3), gland groove (3-1), V-type combined seal ring groove (3-2), copper sleeve groove (3-3), flange bolt (4), piston rod (5), dustproof ring (6), V-type combined seal ring (7), copper sleeve (8), FI guide ring (9), adjusting shim (10), step seal (11), gland bolt (12), gland (13), dustproof groove (13-1), step seal groove (13-2), FI guide groove (13-3), seepage collection groove (14), and oil return pressure reducing port (15); characterized in that: A piston rod (5) is installed in the cylinder body (1), and a piston is installed at the end of the piston rod (5). A hydraulic chamber is reserved between the cavity of the cylinder body (1) and the piston rod (5), and hydraulic oil is installed in the hydraulic chamber. A cylinder head flange (3) is installed in the cylinder port of the cylinder body (1). The cylinder head flange (3) is divided into two sections. One section of the cylinder head flange (3) is set as a flange, and the other section of the cylinder head flange (3) is set as a cylinder head inner sleeve. Two O-ring grooves are reserved on the outside of the cylinder head inner sleeve. An O-ring (2) is installed between the O-ring groove of the cylinder head inner sleeve and the cylinder body (1). Flange bolts (4) are evenly distributed between the flange and the cylinder port wall of the cylinder body (1).

2. The pressure-reducing and sealing device for a large hydraulic cylinder piston rod according to claim 1, characterized in that: A piston rod (5) is installed in the cylinder head flange (3). A gland (13), a V-type combined sealing ring (7), and a copper sleeve (8) are respectively installed between the cylinder head flange (3) and the piston rod (5). Three annular grooves are reserved in the cylinder head flange (3) in a stepped segment. The three annular grooves are respectively set as gland groove (3-1), V-type combined sealing ring groove (3-2), and copper sleeve groove (3-3). A gland (13) is installed in the gland groove (3-1), a V-type combined sealing ring (7) is installed in the V-type combined sealing ring groove (3-2), and a copper sleeve (8) is installed in the copper sleeve groove (3-3).

3. The pressure-reducing and sealing device for a large hydraulic cylinder piston rod according to claim 1, characterized in that: A piston rod (5) is installed in the gland (13). A dustproof ring (6), a step seal (11), and an FI guide ring (9) are respectively installed between the gland (13) and the piston rod (5). A dustproof groove (13-1), a step seal groove (13-2), an oil seepage collection groove (14), and an FI guide groove (13-3) are reserved in sequence on the inner side of the gland (13). An oil return pressure relief port (15) is reserved between one side of the wall of the gland (13) and the oil seepage collection groove (14). A dustproof ring (6) is installed in the dustproof groove (13-1), and a step seal (11) is installed in the step seal groove (13-2). A FI guide ring (9) is set in the guide groove (13-3). A cover screw (12) is evenly distributed between the edge of the cover body of the cover (13) and the cylinder head flange (3). An adjustment pad (10) is set between one side of the cover (13) and the platform of the cover groove (3-1). The V-type combination sealing ring (7), copper sleeve (8), and FI guide ring (9) are set as the inner sealing group. The step seal (11) and dust ring (6) are set as the outer sealing group. The oil seepage collection tank (14) and the oil return pressure reducing port (15) are set as the pressure relief buffer channel. A return pipe is set between the oil return pressure reducing port (15) and the oil tank.

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