Sealing method of large hydraulic cylinder piston rod pressure reduction sealing device

Abstract

The invention relates to the technical field of hydraulic equipment sealing, and discloses a sealing method of a large hydraulic cylinder piston rod decompression sealing device. In the production process, hydraulic oil adheres to the surface of a piston rod, and a layer of oil film is generated; the oil film reduces friction through lubrication to form dynamic sealing; and the service life of the cylinder body is prolonged by more than 50% through dynamic sealing. When the copper sleeve and the V-shaped combined sealing ring are abraded, the copper sleeve and the V-shaped combined sealing ring are manually fastened through a gland screw, the extruded V-shaped combined sealing ring is recombined to form dynamic sealing, and the service life of the cylinder body is prolonged by more than 30% through the dynamic sealing. Dynamic sealing cannot be formed, and leaked oil enters the leaked oil collecting groove to be collected and is discharged into the oil tank through the oil backflow pressure reducing opening; the gland does not generate oil leakage, and the sealing of the step seal and the dustproof ring is in a complete state; according to the structure, the leaked oil collecting groove is designed between the inner sealing set and the outer sealing set, the outer sealing set can be protected, leakage of the cylinder head is prevented, and the service life of the large hydraulic cylinder is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic equipment sealing, in particular to a sealing method for a large hydraulic cylinder piston rod pressure reducing sealing device. Background Art

[0002] At present, the 30MN hydraulic press side cylinder produced by the larger hydraulic cylinder of the metal extruder has a size of φ320mm / φ220mm×1700mm. The cylinder body and the piston rod of the existing metal extruder hydraulic cylinder are supported by three polytetrafluoroethylene-filled guide belts, and two step seals play a sealing role. During production and use, once the guide is worn, the first step seal is slightly worn, and the pressure of the cylinder pressure is transmitted to the second step seal, and the second step seal is damaged, resulting in the dynamic seal of the cylinder head of the hydraulic cylinder often leaking or leaking; once the hydraulic oil leaks from the cylinder head of the hydraulic cylinder, the hydraulic press must be shut down for maintenance, which affects the normal operation or damage of the piston rod, and needs to be shut down for maintenance, which takes a long time to maintain, wastes energy and pollutes the environment, and requires more complex technical means and a full set of sealing spare parts for maintenance, resulting in an increase in the overall equipment operating cost; In view of the above reasons, a sealing method for a large hydraulic cylinder piston rod pressure relief sealing device is proposed. Summary of the invention

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

[0004] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a sealing method for a large hydraulic cylinder piston rod pressure reducing sealing device, wherein the sealing device is composed of: a cylinder body, an O-ring, a cylinder head flange, a gland groove, a V-shaped combined sealing ring groove, a copper sleeve groove, a flange screw, a piston rod, a dust ring, a V-shaped combined sealing ring, a copper sleeve, an FI guide ring, an adjustment pad, a step seal, a gland screw, a gland, a dust groove, a step seal groove, an FI guide groove, an oil seepage collection groove, and an oil reflux pressure reducing port;

[0005] A piston rod is arranged in the cylinder body, a piston is arranged at the end of the piston rod, a hydraulic chamber is reserved between the cavity of the cylinder body and the piston rod, and hydraulic oil is arranged in the hydraulic chamber; a cylinder head flange is arranged in the cylinder mouth of the cylinder body, and the cylinder head flange is arranged in two sections, one section of the cylinder head flange is arranged as a flange plate, and the other section of the cylinder head flange is arranged as a cylinder head inner sleeve, two O-shaped grooves are reserved on the outer side of the cylinder head inner sleeve, an O-shaped ring is arranged between the O-shaped groove of the cylinder head inner sleeve and the cylinder body, and flange screws are evenly arranged between the flange plate and the cylinder mouth wall of the cylinder body;

[0006] A piston rod is arranged in the cylinder head flange, and a gland, a V-shaped combined sealing ring, and a copper sleeve are arranged between the cylinder head flange and the piston rod respectively; three annular grooves are reserved in the cylinder head flange in a stepped manner, and the three annular grooves are respectively arranged as a gland groove, a V-shaped combined sealing ring groove, and a copper sleeve groove; a gland is arranged in the gland groove, a V-shaped combined sealing ring is arranged in the V-shaped combined sealing ring groove, and a copper sleeve is arranged in the copper sleeve groove;

[0007] A piston rod is arranged in the gland, and a dustproof ring, a step seal, and a FI guide ring are respectively arranged between the gland and the piston rod; a dustproof groove, a step seal groove, an oil seepage collection groove, and a FI guide groove are respectively reserved on the inner side of the gland, and a reserved oil reflux pressure relief port is passed through between one side of the gland wall and the oil seepage collection groove; a dustproof ring is arranged in the dustproof groove, a step seal is arranged in the step seal groove, and a FI guide ring is arranged in the FI guide groove, gland screws are evenly arranged between the edge of the gland body and the cylinder head flange, and an adjustment pad is arranged between one side of the gland and the table surface of the gland groove table; a V-shaped combined sealing ring, a copper sleeve, and a FI guide ring are arranged as an inner sealing group, and a step seal and a dustproof ring are arranged as an outer sealing group, the oil seepage collection groove and the oil reflux pressure relief port are arranged as pressure relief buffer channels, and a reflux pipe is arranged between the oil reflux pressure relief port and the oil tank;

[0008] The sealing method is as follows: during the production process, when the cylinder body is continuously pressurized by hydraulic oil, the hydraulic oil pushes the piston to drive the piston rod to move inward, and at the same time, the hydraulic oil in the cylinder body is sealed by the copper sleeve and the V-shaped combined sealing ring; when the piston rod runs repeatedly for a long time, the hydraulic oil adheres to the surface of the piston rod and a layer of oil film is generated; when the piston rod initially runs and the friction between the copper sleeve and the V-shaped combined sealing ring forms a stable and small running-in gap, the oil film of the piston rod fills the running-in gap; the oil film reduces friction through lubrication, and a dynamic seal is formed between the oil film of the piston rod and the gap between the copper sleeve and the V-shaped combined sealing ring; the dynamic seal is: a stable sealing state of pressure running in the cylinder body; the dynamic seal increases the service life of the cylinder body by more than 50%.

[0009] As a further description of the above technical solution:

[0010] When the piston rod runs for a long time, the friction gap between the piston rod and the copper sleeve and V-type combination seal ring wears and expands during the initial operation. The cover screw is used to tighten it manually, and the FI guide ring squeezes the V-type combination seal ring. The squeezed V-type combination seal ring expands inward and the inner hole shrinks. The inner hole of the V-type combination seal ring shrinks and the gap between the piston rod shrinks. The oil film of the piston rod and the V-type combination seal ring are recombined to form a dynamic seal. The dynamic seal again increases the service life of the cylinder by more than 30%.

[0011] As a further description of the above technical solution:

[0012] During the long-term working movement of the piston rod of the cylinder body, when the friction gap between the piston rod and the copper sleeve and the V-type combined sealing ring wears and expands again, the gap between the piston rod and the V-type combined sealing ring expands, and the generated oil leaks outward, and the dynamic seal cannot be formed. The leaked oil enters the oil seepage collection groove for collection and is discharged into the oil tank through the oil reflux pressure relief port; at the same time, the leaked oil in the cylinder body is sealed by the step seal and dust ring of the external sealing group, and the pressure cover does not leak oil, and the seals of the step seal and dust ring are in a complete state.

[0013] As a further description of the above technical solution:

[0014] When oil continuously flows back from the pressure reducing port into the oil tank during the operation of the cylinder body, the cylinder body needs to be shut down for maintenance; during the maintenance process of the cylinder body, all the gland screws on the gland are manually removed, the piston rod and its inner and outer seal groups are manually taken out, and the copper sleeve and V-shaped combination seal ring are replaced, and then the maintenance is completed; after the cylinder body is repaired, the above-mentioned production operation state is resumed.

[0015] Beneficial effects: The structure of the present invention is a double-pass seal of an inner seal group and an outer seal group; a combination seal and step seal are used, and the gap between the two seals is designed with an oil seepage collection groove structure, which can protect the outer seal group of the second seal. A dynamic seal is formed between the oil film of the piston rod and the gap between the copper sleeve and the V-type combination seal ring; the dynamic seal increases the service life of the cylinder by more than 50%; when the friction gap between the piston rod and the copper sleeve and the V-type combination seal ring is worn and expanded, it is tightened manually through the gland screw, and the FI guide ring squeezes the V-type combination seal ring, and the squeezed V can shrink the inner hole, re-form a dynamic seal, and increase the service life of the cylinder by more than 30% again; when the first V-type combination seal ring leaks or seeps oil, the seepage oil is collected through the oil seepage collection groove, and then flows directly back into the oil tank through the oil return pressure relief port, and no pressure is generated between the double-pass seals, which effectively protects the step seal of the outer seal group. The step seal can continuously seal, effectively prevent leakage of the cylinder head, protect the production environment, increase the service life of large hydraulic cylinders, and reduce the frequency of maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below in conjunction with the accompanying drawings:

[0017] Figure 1 It is a schematic diagram of the general assembly structure of the present invention;

[0018] Figure 2 yes Figure 1 Schematic diagram of the local structure;

[0019] Figure 3 yes Figure 2 Schematic diagram of the local structure;

[0020] Figure 4 yes Figure 1 Schematic diagram of the partial structure of the cylinder head flange;

[0021] Figure 5 yes Figure 1 Schematic diagram of the local structure of the gland;

[0022] Figure 1 , 2 , 3, 4, 5: cylinder body 1, O-ring 2, cylinder head flange 3, gland groove 3-1, V-type combination sealing ring groove 3-2, copper sleeve groove 3-3, flange screw 4, piston rod 5, dust ring 6, V-type combination sealing ring 7, copper sleeve 8, FI guide ring 9, adjustment gasket 10, Step seal 11, gland screw 12, gland 13, dust groove 13-1, Step seal groove 13-2, FI guide groove 13-3, oil seepage collection groove 14, oil reflux pressure relief port 15. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below in conjunction with embodiments and specific implementation modes:

[0024] Example 1

[0025] The large hydraulic cylinder piston rod pressure reducing sealing device of the present invention is as follows: Figure 1-5 As shown, it is installed at the cylinder mouth of the cylinder body 1;

[0026] A piston rod 5 is arranged in the cylinder body 1, a piston is arranged at the end of the piston rod 5, a hydraulic cavity is reserved between the cavity of the cylinder body 1 and the piston rod 5, and hydraulic oil is arranged in the hydraulic cavity; a cylinder head flange 3 is arranged in the cylinder mouth of the cylinder body 1, and the cylinder head flange 3 is arranged in two sections, one section of the cylinder head flange 3 is arranged as a flange plate, and the other section of the cylinder head flange 3 is arranged as a cylinder head inner sleeve, two O-shaped grooves are reserved on the outer side of the cylinder head inner sleeve, an O-shaped ring 2 is arranged between the O-shaped groove of the cylinder head inner sleeve and the cylinder body 1, and flange screws 4 are evenly arranged between the flange plate and the cylinder mouth wall of the cylinder body 1;

[0027] A piston rod 5 is arranged in the cylinder head flange 3, and a gland 13, a V-shaped combined sealing ring 7, and a copper sleeve 8 are arranged between the cylinder head flange 3 and the piston rod 5 respectively; three annular grooves are reserved in the cylinder head flange 3 in a stepped manner, and the three annular grooves are respectively arranged as a gland groove 3-1, a V-shaped combined sealing ring groove 3-2, and a copper sleeve groove 3-3; a gland 13 is arranged in the gland groove 3-1, a V-shaped combined sealing ring groove 3-2 is arranged in the V-shaped combined sealing ring groove 7, and a copper sleeve 8 is arranged in the copper sleeve groove 3-3;

[0028] The piston rod 5 is arranged in the gland 13, and a dustproof ring 6, a step seal 11, and an FI guide ring 9 are arranged 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 on the inner side of the gland 13 in sequence, and an oil return pressure relief port 15 is reserved between one side of the gland 13 wall and the oil seepage collection groove 14; a dustproof ring 6 is arranged in the dustproof groove 13-1, a step seal 11 is arranged in the step seal groove 13-2, and an FI guide groove 13-3 is provided with an FI guide ring 9, a gland screw 12 is evenly arranged between the cover edge of the gland 13 and the cylinder head flange 3, an adjustment pad 10 is arranged between one side of the gland 13 and the table surface of the gland groove table 3-1; the V-shaped combined sealing ring 7, the copper sleeve 8, and the FI guide ring 9 are arranged as an inner sealing group, the step seal 11 and the dust ring 6 are arranged as an outer sealing group, the oil seepage collection groove 14 and the oil return pressure relief port 15 are arranged as a pressure relief buffer channel, and a return pipe is arranged between the oil return pressure relief port 15 and the oil tank;

[0029] During the production process, when the cylinder body 1 is continuously pressurized by hydraulic oil, the hydraulic oil pushes the piston to drive the piston rod 5 to move inward. At the same time, the hydraulic oil in the cylinder body 1 is sealed by the copper sleeve 8 and the V-shaped combined sealing ring 7; when the piston rod 5 runs repeatedly for a long time, the hydraulic oil adheres to the surface of the piston rod 5 and a layer of oil film is generated; when the piston rod 5 initially runs, the friction between the copper sleeve 8 and the V-shaped combined sealing ring 7 forms a stable and small running-in gap, and the oil film of the piston rod 5 fills the running-in gap; the oil film reduces friction through lubrication, and a dynamic seal is formed between the oil film of the piston rod 5 and the gap between the copper sleeve 8 and the V-shaped combined sealing ring 7; the dynamic seal is: a stable sealing state of pressure operation in the cylinder body 1; the dynamic seal increases the service life of the cylinder body 1 by more than 50%.

[0030] Example 2

[0031] When the piston rod 5 runs for a long time, and the friction gap between the piston rod 5 and the copper sleeve 8 and the V-type combination sealing ring 7 during the initial operation is worn and expanded, it is manually tightened through the cover screw 12, and the FI guide ring 9 squeezes the V-type combination sealing ring 7. The squeezed V-type combination sealing ring 7 expands inward and the inner hole shrinks. The inner hole of the V-type combination sealing ring 7 shrinks and the gap between the piston rod 5 shrinks, and the oil film of the piston rod 5 and the V-type combination sealing ring 7 are recombined to form: dynamic sealing, which again increases the service life of the cylinder body 1 by more than 30%.

[0032] Example 3

[0033] During the long-term working movement of the piston rod 5 of the cylinder body 1, when the friction gap between the piston rod 5 and the copper sleeve 8 and the V-type combined sealing ring 7 is worn and expanded again, the gap between the piston rod 5 and the V-type combined sealing ring 7 is expanded, and the generated oil leaks outward, and the dynamic seal cannot be formed. The leaked oil enters the oil seepage collection groove 14 for collection and is discharged into the oil tank through the oil return pressure relief port 15; at the same time, the leaked oil in the cylinder body 1 is sealed by the step seal 11 and the dust ring 6 of the external sealing group, and the pressure cover 13 does not produce oil leakage, and the seals of the step seal 11 and the dust ring 6 are in a complete state.

[0034] Example 4

[0035] When oil continuously flows back through the pressure reducing port 15 and is discharged into the oil tank during the operation of the cylinder body 1, the cylinder body 1 needs to be shut down for maintenance. During the maintenance of the cylinder body 1, all the gland screws 12 on the gland 13 are manually removed, the piston rod 5 and its inner and outer seal groups are manually taken out, and the copper sleeve 8 and the V-shaped combined seal ring 7 are replaced. The maintenance is then completed after the cylinder body 1 is restored. After the maintenance, the cylinder body 1 resumes the above-mentioned production operation state.

[0036] The sealing device of the present invention adopts a double sealing structure of an inner sealing group and an outer sealing group, wherein the inner sealing group is composed of a V-shaped combined sealing ring 7, a copper sleeve 8 and an FI guide ring 9, and the outer sealing group is composed of a step seal 11 and a dust ring 6; the inner sealing group is mainly used to withstand the high-pressure hydraulic oil in the hydraulic cavity, and form a dynamic seal with the surface of the piston rod 5 through the V-shaped combined sealing ring 7; the outer sealing group is used to block dust and impurities in the external environment, and at the same time prevent the hydraulic oil leaked from the inner sealing group from overflowing.

[0037] In addition, the oil seepage collection groove 14 and the oil return pressure relief port 15 together form a pressure relief buffer channel. When the inner seal group leaks, the hydraulic oil will enter the oil return pressure relief port 15 through the oil seepage collection groove 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 seal group.

[0038] Through the above structural design, the present invention can effectively solve the problems of easy leakage, high maintenance frequency, serious environmental pollution, etc. of 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 sealing method for a large hydraulic cylinder piston rod pressure reducing sealing device, the large hydraulic cylinder piston rod pressure reducing sealing device comprising: a cylinder body (1), an O-ring (2), a cylinder head flange (3), a gland groove (3-1), a V-shaped combined sealing ring groove (3-2), a copper sleeve groove (3-3), a flange screw (4), a piston rod (5), a dust ring (6), a V-shaped combined sealing ring (7), a copper sleeve (8), an FI guide ring (9), an adjustment pad (10), a step seal (11), a gland screw (12), a gland (13), a dust groove (13-1), a step seal groove (13-2), an FI guide groove (13-3), an oil seepage collection groove (14), and an oil return pressure reducing port (15); characterized in that: A piston rod (5) is arranged in the cylinder body (1), a piston is arranged 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 arranged in the hydraulic chamber; a cylinder head flange (3) is arranged in the cylinder mouth of the cylinder body (1), the cylinder head flange (3) is divided into two sections, one section of the cylinder head flange (3) is arranged as a flange plate, and the other section of the cylinder head flange (3) is arranged as a cylinder head inner sleeve, two O-shaped grooves are reserved on the outer side of the cylinder head inner sleeve, an O-shaped ring (2) is arranged between the O-shaped groove of the cylinder head inner sleeve and the cylinder body (1), and flange screws (4) are evenly arranged between the flange plate and the cylinder mouth wall of the cylinder body (1); A piston rod (5) is arranged in the cylinder head flange (3), and a gland (13), a V-shaped combined sealing ring (7), and a copper sleeve (8) are arranged between the cylinder head flange (3) and the piston rod (5); three annular grooves are reserved in a stepped manner in the cylinder head flange (3), and the three annular grooves are respectively arranged as a gland groove (3-1), a V-shaped combined sealing ring groove (3-2), and a copper sleeve groove (3-3); a gland (13) is arranged in the gland groove (3-1), a V-shaped combined sealing ring groove (3-2) is arranged in the V-shaped combined sealing ring groove (3-2), and a copper sleeve (8) is arranged in the copper sleeve groove (3-3); A piston rod (5) is arranged in the gland (13), and a dustproof ring (6), a step seal (11), and an FI guide ring (9) are arranged 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 the inner side of the gland (13) in sequence, and a reserved oil return pressure relief port (15) is passed through between one side of the gland (13) wall and the oil seepage collection groove (14); a dustproof ring (6) is arranged in the dustproof groove (13-1), a step seal (11) is arranged in the step seal groove (13-2), and an FI guide ring (9) is arranged in the FI guide groove (13-3); gland screws (12) are evenly arranged between the cover edge of the gland (13) and the cylinder head flange (3), and an adjustment pad (10) is arranged between one side of the gland (13) and the table surface of the gland groove table (3-1); The V-shaped combined sealing ring (7), the copper sleeve (8), and the FI guide ring (9) are provided as an inner sealing group, the step seal (11) and the dust ring (6) are provided as an outer sealing group, the oil seepage collection groove (14) and the oil return pressure relief port (15) are provided as a pressure relief buffer channel, and a return pipe is provided between the oil return pressure relief port (15) and the oil tank; According to the sealing method, during the production process, when the cylinder (1) is continuously pressurized by hydraulic oil, the hydraulic oil pushes the piston to drive the piston rod (5) to move inward, and at the same time, the hydraulic oil in the cylinder (1) is sealed by the copper sleeve (8) and the V-shaped combined sealing ring (7); when the piston rod (5) is repeatedly operated for a long time, the surface of the piston rod (5) adheres to the hydraulic oil and forms an oil film; when the piston rod (5) initially operates, the friction between the copper sleeve (8) and the V-shaped combined sealing ring (7) forms a stable and small running-in gap, and the oil film of the piston rod (5) fills the running-in gap; the oil film reduces friction by lubrication, and a dynamic seal is formed between the oil film of the piston rod (5) and the gap between the copper sleeve (8) and the V-shaped combined sealing ring (7); the dynamic seal is: a stable sealing state of the pressure operation in the cylinder (1); the dynamic seal increases the service life of the cylinder (1) by more than 50%.

2. The sealing method of a large hydraulic cylinder piston rod pressure reducing sealing device according to claim 1, characterized in that: When the piston rod (5) is in operation for a long time, and the friction gap between the piston rod (5) and the copper sleeve (8) and the V-type combined seal ring (7) is worn and enlarged during the initial operation, the piston rod (5) is manually tightened by the gland screw (12), and the FI guide ring (9) squeezes the V-type combined seal ring (7). The squeezed V-type combined seal ring (7) expands inward and the inner hole shrinks. The inner hole of the V-type combined seal ring (7) shrinks and the gap between the piston rod (5) is reduced. The oil film of the piston rod (5) and the V-type combined seal ring (7) are recombined to form a dynamic seal. The dynamic seal again increases the service life of the cylinder body (1) by more than 30%.

3. The sealing method of a large hydraulic cylinder piston rod pressure reducing sealing device according to claim 1, characterized in that: During the long-term operation of the piston rod (5) of the cylinder body (1), when the friction gap between the piston rod (5) and the copper sleeve (8) and the V-type combined seal ring (7) is worn and expanded again, the gap between the piston rod (5) and the V-type combined seal ring (7) is expanded, and the generated oil leaks outward, and the dynamic seal cannot be formed. The leaked oil enters the oil seepage collection groove (14) for collection and is discharged into the oil tank through the oil return pressure relief port (15); at the same time, the leaked oil in the cylinder body (1) is sealed by the step seal (11) and the dust ring (6) of the external seal group, and the pressure cover (13) does not produce oil leakage, and the seal of the step seal (11) and the dust ring (6) is in a complete state.

4. The sealing method of a large hydraulic cylinder piston rod pressure reducing sealing device according to claim 1, characterized in that: When oil continuously flows back through the pressure reducing port (15) and is discharged into the oil tank during the operation of the cylinder body (1), the cylinder body (1) needs to be shut down for maintenance. During the maintenance of the cylinder body (1), all the gland screws (12) on the gland (13) are manually removed, the piston rod (5) and its inner seal group and outer seal group are manually taken out, and the copper sleeve (8) and the V-shaped combined seal ring (7) are replaced. After the maintenance, the cylinder body (1) resumes the above-mentioned production operation state.

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