Method for compensating the x-shaped lip gap of a plug-in valve for multi-directional pressure oil sealing

Abstract

This invention relates to the field of hydraulic technology and discloses a method for X-shaped lip gap compensation in multi-directional pressure oil sealing of cartridge valves. The method includes steps 1: gap detection and sealing ring adaptation at the sealing mating surface; step 2: pretreatment of the sealing surface and sealing groove; step 3: positioning and installation of the X-shaped lip sealing ring and initial compression setting; step 4: stepped pressure application of multi-directional pressure oil and adaptive gap compensation of the X-shaped lip; step 5: gap compensation effect detection and calibration; and step 6: compensation shaping and sealing protection. This method achieves multi-directional pressure oil sealing and adaptive gap compensation, solving the problem of oil leakage at its root. Utilizing the four-lip structure of the X-shaped lip sealing ring, the four lips precisely correspond to the four pressure oil action directions: the valve core axial direction and the valve sleeve radial direction, achieving synchronous sealing of multi-directional pressure oil. This overcomes the limitation of traditional sealing methods that can only seal in one direction, effectively filling oil cavitation gaps and production tolerance gaps of 0.05~0.2mm.

Description

Technical Field

[0001] This invention relates to the field of hydraulic technology, specifically to a method for compensating the gap of the X-shaped lip of a cartridge valve multi-directional pressure oil seal. Background Technology

[0002] Hydraulic cartridge valves are core control components in the hydraulic systems of heavy equipment in engineering machinery, metallurgy, and mining. Among them, hydraulic cartridge valves with a nominal diameter of DN10~DN25 are commonly used in various hydraulic systems due to their wide adaptability. The sealing effect of the valve core, valve sleeve, and valve body sealing surfaces directly determines the operational stability of the hydraulic system and the operating efficiency of the equipment. In actual industrial conditions, the pressure oil in the hydraulic system does not act in a single direction, but continuously acts on the sealing surfaces of the cartridge valve in four directions: axial direction of the valve core, radial direction of the valve sleeve, circumferential direction of the valve body, and oblique direction of the valve core-valve sleeve mating surface. This places stringent requirements on the multi-directional sealing capability of the sealing structure.

[0003] Currently, the industry commonly uses conventional static sealing rings to seal these types of cartridge valves. Due to structural design limitations, these rings can only provide sealing protection against pressure oil in one direction, failing to cope with simultaneous impacts from multi-directional pressure oil. Furthermore, their pressure elasticity compensation is only 0.1~0.2mm, indicating weak gap compensation capability. During the manufacturing process of cartridge valves, the sealing surfaces of the valve core, valve sleeve, and valve body will have a 0.05~0.2mm clearance due to slight manufacturing tolerances. Simultaneously, during equipment operation, oil cavitation will create irregular, uneven pits on the sealing surfaces, also within the 0.05~0.2mm range. Traditional static sealing rings cannot achieve comprehensive sealing against multi-directional pressure oil, nor can they effectively fill and compensate for the aforementioned cavitation and manufacturing tolerance gaps. This leads to oil leakage problems at the sealing surfaces of cartridge valves shortly after they are put into use.

[0004] Oil leakage not only causes unstable oil pressure inside the hydraulic system, directly affecting the normal operation of the equipment, but also requires the disassembly and rework of the faulty cartridge valve, significantly increasing the labor and material losses during production and maintenance. At the same time, leaking hydraulic oil causes oil pollution on the production site, which can easily lead to safety accidents such as equipment lubrication failure and short circuits in electrical components. This also goes against the environmental protection requirements of industrial production, becoming a core issue restricting the improvement of the sealing performance of hydraulic cartridge valves and the long-term stable operation of the hydraulic system. Summary of the Invention

[0005] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides an X-shaped lip gap compensation method for multi-directional pressure oil seals of cartridge valves. This method has advantages such as easy oil leakage at the sealing joint surface, and solves the problem of multi-directional pressure oil seals and adaptive gap compensation, thereby addressing the oil leakage problem at its root.

[0006] (II) Technical Solution To achieve the aforementioned multi-directional pressure oil sealing and adaptive gap compensation, and to fundamentally solve the oil leakage problem, this invention provides the following technical solution: an X-shaped lip gap compensation method for multi-directional pressure oil sealing of cartridge valves, comprising: step 1: gap detection of sealing mating surface and fitting of sealing ring; step 2: pretreatment of sealing surface and sealing groove; step 3: positioning and installation of X-shaped lip sealing ring and setting of initial compression amount; step 4: multi-directional pressure oil stepped pressure application and adaptive gap compensation of X-shaped lip; step 5: gap compensation effect detection and calibration; and step 6: compensation shaping and sealing protection. Step 5: gap compensation effect detection and calibration includes step 501 leakage detection, step 502 performance re-inspection, and step 503 deviation calibration. Step 1: Detection of the gap between the sealing surfaces and fitting of the sealing ring; A high-precision gap detector is used to perform full-dimensional inspection of the sealing surfaces of the valve core, valve sleeve and valve body of the cartridge valve. The inspection accuracy is ≤0.01mm. The focus is on inspecting the gaps caused by oil cavitation and the fit gaps caused by the manufacturing tolerance of the parts. The gap values ​​in each direction are recorded to ensure that the gaps to be compensated are ≤0.2mm (parts that exceed this range need to be repaired first). Based on the dimensions of the sealing groove (groove width 8±0.02mm, groove depth 4.5±0.01mm) and the measured gap value, a suitable X-shaped lip sealing ring is selected, and the elasticity of the sealing ring is tested: at a normal temperature of 25℃, a radial tensile force is applied to the sealing ring to ensure that there is no permanent deformation when its elongation rate is ≤15%. At the same time, the four lips of the sealing ring are checked for missing glue, cracks, and deformation to ensure that it has sufficient elastic deformation compensation capacity.

[0007] Preferably, step 2 involves the pretreatment of the sealing surface and the sealing groove. Use a dust-free cleaning cloth soaked in analytical grade anhydrous ethanol to repeatedly wipe the sealing surfaces of the valve core, valve sleeve, and valve body, as well as the inner wall of the sealing groove, to remove surface oil, iron filings, and processing dust impurities. Wipe along the grain of the sealing surface to avoid leaving any fiber residue on the cleaning cloth. After wiping, place the sealing surface and sealing groove in a dry environment at room temperature and let them air dry naturally for no less than 5 minutes. Do not use blowing or heating to accelerate the drying process, as this may cause the sealing surface to deform due to temperature differences and damage the gap reference. If there are slight scratches with a depth of <0.05mm on the sealing surface, gently polish them along the grain with 800# metallographic sandpaper. After polishing, wipe clean again with anhydrous ethanol. After polishing, check the surface roughness of the sealing surface to ensure Ra≤0.8μm.

[0008] Preferably, step 3 involves positioning and installing the X-shaped lip seal ring and setting the initial compression amount. Apply a thin layer of hydraulic grease evenly to the four lips and outer circumference of the X-shaped lip seal ring, with a grease application amount ≤ 0.5 g / cm². 2 This is to prevent excessive grease buildup from creating additional gaps and affecting the sealing and compensation effect; The sealing ring is slowly embedded into the sealing groove using a pressing method. A special pressure block is used to apply force evenly along the circumference of the sealing ring to ensure that the sealing ring is completely fitted to the inner wall of the sealing groove without wrinkles or folds. After installation, the four lips of the sealing ring are precisely aligned with the four directions of pressure oil action: the axial direction of the valve core, the radial direction of the valve sleeve, the circumferential direction of the valve body, and the oblique direction of the valve core-valve sleeve mating surface. The radial offset of the sealing ring is checked to be ≤0.03mm to prevent compensation failure caused by positioning deviation. Align the valve sleeve and valve body with the pre-installed sealing ring according to the assembly standard, ensuring coaxiality ≤0.05mm. Then slowly insert the valve core along the central axis and tighten it according to the valve diameter using a torque wrench: DN10 80±5N・m, DN15 95±5N・m, DN20 110±5N・m, DN25 120±5N・m. After tightening, check the initial compression of the four lips of the sealing ring to ensure that the compression is stable at 15%~20% and the single lip compression deviation is ≤0.02mm. The initial compression achieves basic sealing, while controlling the friction of the valve core movement at 5~8N to compensate for the manufacturing tolerance of the parts and reserve elastic deformation space for clearance compensation of subsequent pressure oil drive.

[0009] Preferably, step 4 involves multi-directional pressure oil stepwise pressurization and X-shaped lip adaptive clearance compensation. Connect the cartridge valve assembly that has completed initial compression to the hydraulic test bench, seal the test pipeline to ensure that there is no external leakage in the pipeline, and reserve pressure oil input ports in four directions: valve core axial direction, valve sleeve radial direction, valve body circumferential direction, and valve core-valve sleeve mating surface oblique direction. Hydraulic oil is introduced in four directions using a stepped synchronous pressure method, with each pressurization increasing by 5 MPa and holding the pressure for 5 minutes after each increase. The elastic deformation of the X-shaped lip is observed to ensure that the lips in each direction deform uniformly with increasing pressure, without any local over-compression. The pressure is gradually increased to 1.5 times the rated working pressure of the cartridge valve (31.5 MPa). During this process, the sealing ring is subjected to multi-directional pressure oil, and its inner lip undergoes adaptive elastic deformation. The amount of deformation matches the gap of the sealing mating surface, achieving precise filling and compensation for cavitation gaps and tolerance gaps. Hold the pressure at 31.5MPa for 30 minutes, keeping the hydraulic system pressure fluctuation ≤±0.5MPa, to ensure that the X-shaped lip fully completes deformation compensation and remains stable, so that the lip and the sealing surface are completely fitted together, eliminating all effective gaps.

[0010] Preferably, in step 501, leakage detection involves: during the pressure holding process, using the soap bubble method to check for leaks at each sealing joint surface. The soap bubble solution is evenly applied to the joint surface, and no bubbles are generated, indicating no leakage. After the pressure holding is completed, the system leakage is checked to ensure that the leakage is ≤0.01mL / min.

[0011] Preferably, in step 502, the performance is retested by slowly depressurizing to normal pressure and testing the friction force of the valve core movement to ensure that the friction force remains within the range of 5~8N. This avoids excessive deformation of the lip, which could lead to excessive friction force causing valve core jamming, or insufficient friction force causing the sealing ring to loosen.

[0012] Preferably, in step 503, deviation calibration: if slight leakage or incomplete gap compensation is detected, the original tightening torque is finely adjusted by ±5 N·m, and step four is repeated for step-by-step pressure compensation. After holding the pressure for 10 minutes, the test is repeated until the compensation effect meets the standard.

[0013] Preferably, step 6 involves compensation, shaping, and sealing protection. For cartridge valve assemblies that meet the compensation requirements, apply a thin layer of anti-rust oil evenly to each sealing mating surface and exposed parts of the sealing ring. The thickness of the anti-rust oil should be ≤0.02mm to prevent the anti-rust oil from entering the sealing gap and damaging the fit between the lip and the mating surface. The cartridge valve sealing parts are tightly wrapped with a transparent plastic protective film to prevent impurities and dust from entering the sealing groove during transportation, storage and subsequent assembly, or external forces from scratching the sealing mating surface and displacing the sealing ring, so as to ensure that the gap compensation state of the X-shaped lip is maintained for a long time. During the subsequent assembly of cartridge valves, avoid applying axial or radial external forces to the sealing parts to ensure the coaxiality of the valve core, valve sleeve, and valve body, and prevent the recurrence of the compensated sealing gap.

[0014] (III) Beneficial Effects Compared with the prior art, the present invention provides a method for compensating the X-shaped lip clearance of a multi-directional pressure oil seal for cartridge valves, which has the following beneficial effects: 1. This method for X-shaped lip gap compensation in multi-directional pressure oil sealing of cartridge valves achieves multi-directional pressure oil sealing and adaptive gap compensation, fundamentally solving the problem of oil leakage. Utilizing the four-lip structure of the X-shaped lip sealing ring, the four lips precisely correspond to the four directions of pressure oil action: the axial direction of the valve core and the radial direction of the valve sleeve. This achieves synchronous sealing of multi-directional pressure oil, overcoming the limitation of traditional sealing methods that can only seal in one direction. Simultaneously, the X-shaped lip sealing ring can compensate for pressure of 0.3~0.5mm, effectively filling oil cavitation gaps and production tolerance gaps of 0.05~0.2mm. Combined with a multi-directional stepped pressure application method, the sealing ring lips undergo adaptive elastic deformation under pressure oil action, completely fitting the sealing surface and fundamentally solving the oil leakage problem of cartridge valves.

[0015] 2. The X-shaped lip gap compensation method for the multi-directional pressure oil seal of the cartridge valve, with precise positioning and initial compression control, significantly improves the assembly stability of the sealing structure. This method, through special pressure block pressing and precision testing, controls the radial offset of the X-shaped lip sealing ring in the sealing groove to ≤0.03mm, ensuring accurate positioning of the sealing ring without displacement. At the same time, the tightening torque is precisely set according to the cartridge valve diameter, so that the initial compression of the four lips of the sealing ring is stable at 15%~20%, and the single lip compression deviation is ≤0.2mm. The friction force of the valve core movement is also controlled at 5~8N. This method not only achieves basic sealing through initial compression and compensates for the manufacturing tolerance of parts, but also reserves reasonable elastic deformation space for subsequent pressure oil-driven gap compensation. It effectively prevents the sealing ring from falling off, flanging, or local excessive compression failure during assembly and equipment operation, thus improving the overall stability of the sealing structure.

[0016] 3. The X-shaped lip gap compensation method for the multi-directional pressure oil seal of the cartridge valve employs a stepped pressure application and full-process testing and calibration to ensure the effectiveness and accuracy of gap compensation. This method uses a stepped synchronous pressure application to introduce hydraulic oil in four directions, increasing the pressure by 5MPa each time and holding it for 5 minutes to ensure that the sealing ring lip deforms uniformly with increasing pressure, avoiding compensation failure caused by local deformation. The pressure is held for 30 minutes at a test pressure 1.5 times the rated working pressure of the cartridge valve, with pressure fluctuation controlled to ≤±0.5MPa, allowing the lip to fully complete deformation compensation and remain stable. Simultaneously, the compensation effect is verified from all dimensions through soap bubble leak detection, leakage detection (≤0.01mL / min), and valve core friction re-inspection. If deviations occur, compensation can be re-adjusted by fine-tuning the tightening torque to ensure that the gap compensation effect meets the standard, solving the problems of traditional sealing compensation lacking detection and uncontrollable effect.

[0017] 4. The X-shaped lip gap compensation method for the multi-directional pressure oil seal of the cartridge valve enables successful one-time assembly of the cartridge valve sealing parts, significantly reducing production and maintenance costs. This method establishes precise parameter standards and standardized operating procedures for each step, from sealing surface inspection and sealing ring adaptation to positioning installation, pressure compensation, and effect testing. Strict precision control and effect verification are carried out throughout the process, ensuring a 100% first-time assembly pass rate for the cartridge valve sealing parts. It completely avoids the repeated disassembly and rework caused by oil leakage problems in traditional sealing processes, greatly reducing labor and material losses caused by rework, while improving the online assembly efficiency of hydraulic cartridge valves and reducing overall production and maintenance costs.

[0018] 5. The method for compensating the X-shaped lip gap of the multi-directional pressure oil seal of the cartridge valve includes compensation shaping and protection measures to ensure the long-term maintenance of the sealing compensation effect. For cartridge valve assemblies that meet the compensation standard, this method uses a thin layer of anti-rust oil (thickness ≤0.02mm) and a transparent plastic protective film to shape and protect the sealing parts, preventing impurities from entering the sealing groove, external forces from scratching the sealing mating surface, or causing the sealing ring to shift during transportation and storage. At the same time, it requires that axial and radial external forces be avoided on the sealing parts during subsequent assembly to ensure the coaxiality of the valve core, valve sleeve, and valve body, prevent the recurrence of the compensated sealing gap, and ensure the long-term maintenance of the X-shaped lip gap compensation state, thereby improving the durability of the cartridge valve's sealing performance and the overall service life of the hydraulic system.

[0019] 6. The X-shaped lip clearance compensation method for the multi-directional pressure oil seal of the cartridge valve is standardized in operation, adaptable to the existing production system, and highly feasible. Each operation step of this method has clear parameter indicators and execution requirements, and no complex special equipment is required. The clearance tester, torque wrench, and hydraulic test bench used are all conventional equipment in the production of hydraulic cartridge valves. The sealing ring can be directly pressed into the sealing groove to complete the installation without the need for additional sealing auxiliary parts, which simplifies the operation process and is easy for on-site workers to implement. It can be directly adapted to the existing online assembly production system of hydraulic cartridge valves, with low process modification cost and strong feasibility. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] This solution provides a technical solution, specifically, a method for compensating the gap of the X-shaped lip of a multi-directional pressure oil seal for a cartridge valve, including the following steps: Step 1: Detection of the gap between the sealing mating surfaces and adaptation of the sealing ring; A high-precision gap detector is used to perform full-dimensional inspection of the sealing surfaces of the valve core, valve sleeve and valve body of the cartridge valve. The inspection accuracy is ≤0.01mm. The focus is on inspecting the gaps caused by oil cavitation and the fit gaps caused by the manufacturing tolerance of the parts. The gap values ​​in each direction are recorded to ensure that the gaps to be compensated are ≤0.2mm (parts that exceed this range need to be repaired first). Based on the dimensions of the sealing groove (groove width 8±0.02mm, groove depth 4.5±0.01mm) and the measured gap value, a suitable X-shaped lip sealing ring is selected, and the elasticity of the sealing ring is tested: at a normal temperature of 25℃, a radial tensile force is applied to the sealing ring to ensure that there is no permanent deformation when its elongation rate is ≤15%. At the same time, the four lips of the sealing ring are checked for missing glue, cracks, and deformation to ensure that it has sufficient elastic deformation compensation capacity. Step 2: Pre-treatment of the sealing surface and sealing groove; Use a dust-free cleaning cloth soaked in analytical grade anhydrous ethanol to repeatedly wipe the sealing surfaces of the valve core, valve sleeve, and valve body, as well as the inner wall of the sealing groove, to remove surface oil, iron filings, and processing dust impurities. Wipe along the grain of the sealing surface to avoid leaving any fiber residue on the cleaning cloth. After wiping, place the sealing surface and sealing groove in a dry environment at room temperature and let them air dry naturally for no less than 5 minutes. Do not use blowing or heating to accelerate the drying process, as this may cause the sealing surface to deform due to temperature differences and damage the gap reference. If there are slight scratches with a depth of <0.05mm on the sealing surface, gently polish them along the grain with 800# metallographic sandpaper. After polishing, wipe them clean again with anhydrous ethanol. After polishing, check the surface roughness of the sealing surface to ensure that Ra≤0.8μm. Step 3: Positioning and installing the X-shaped lip seal ring and setting the initial compression amount; Apply a thin layer of hydraulic grease evenly to the four lips and outer circumference of the X-shaped lip seal ring, with a grease application amount ≤ 0.5 g / cm². 2 This is to prevent excessive grease buildup from creating additional gaps and affecting the sealing and compensation effect; The sealing ring is slowly embedded into the sealing groove using a pressing method. A special pressure block is used to apply force evenly along the circumference of the sealing ring to ensure that the sealing ring is completely fitted to the inner wall of the sealing groove without wrinkles or folds. After installation, the four lips of the sealing ring are precisely aligned with the four directions of pressure oil action: the axial direction of the valve core, the radial direction of the valve sleeve, the circumferential direction of the valve body, and the oblique direction of the valve core-valve sleeve mating surface. The radial offset of the sealing ring is checked to be ≤0.03mm to prevent compensation failure caused by positioning deviation. Align the valve sleeve and valve body with the pre-installed sealing ring according to the assembly standard, ensuring coaxiality ≤0.05mm. Then slowly insert the valve core along the central axis and tighten it according to the valve diameter using a torque wrench: DN10 80±5N・m, DN15 95±5N・m, DN20 110±5N・m, DN25 120±5N・m. After tightening, check the initial compression of the four lips of the sealing ring to ensure that the compression is stable at 15%~20% and the single lip compression deviation is ≤0.02mm. The initial compression achieves basic sealing, while controlling the friction of the valve core movement at 5~8N to compensate for the manufacturing tolerance of the parts and reserve elastic deformation space for clearance compensation of the subsequent pressure oil drive. Step 4: Multi-directional pressure oil stepped pressurization and X-shaped lip adaptive clearance compensation; Connect the cartridge valve assembly that has completed initial compression to the hydraulic test bench, seal the test pipeline to ensure that there is no external leakage in the pipeline, and reserve pressure oil input ports in four directions: valve core axial direction, valve sleeve radial direction, valve body circumferential direction, and valve core-valve sleeve mating surface oblique direction. Hydraulic oil is introduced in four directions using a stepped synchronous pressure method, with each pressurization increasing by 5 MPa and holding the pressure for 5 minutes after each increase. The elastic deformation of the X-shaped lip is observed to ensure that the lips in each direction deform uniformly with increasing pressure, without any local over-compression. The pressure is gradually increased to 1.5 times the rated working pressure of the cartridge valve (31.5 MPa). During this process, the sealing ring is subjected to multi-directional pressure oil, and its inner lip undergoes adaptive elastic deformation. The amount of deformation matches the gap of the sealing mating surface, achieving precise filling and compensation for cavitation gaps and tolerance gaps. Hold the pressure at 31.5MPa for 30 minutes, keeping the hydraulic system pressure fluctuation ≤±0.5MPa, to ensure that the X-shaped lip fully completes deformation compensation and remains stable, so that the lip and the sealing surface are completely fitted together, eliminating all effective gaps; Step 5: Gap compensation effect detection and calibration; Step 501 Leakage Detection: During the pressure holding process, the soap bubble method is used to check for leaks at each sealing joint surface. The soap bubble solution is evenly applied to the joint surface, and no bubbles are generated, indicating no leakage. After the pressure holding is completed, the leakage of the system is checked to ensure that the leakage is ≤0.01mL / min. Step 502 Performance Retest: Slowly depressurize to normal pressure and test the friction of the valve core movement. Ensure that the friction is still within the range of 5~8N to avoid excessive deformation of the lip, which may cause excessive friction and valve core jamming, or insufficient friction, which may cause the sealing ring to loosen. Step 503 Deviation Calibration: If slight leakage or incomplete gap compensation is found during the test, finely adjust the original tightening torque by ±5 N·m, and repeat the step-by-step pressure compensation according to Step 4. Hold the pressure for 10 minutes and test again until the compensation effect meets the standard. Step 6: Compensation, shaping, and sealing protection; For cartridge valve assemblies that meet the compensation requirements, apply a thin layer of anti-rust oil evenly to each sealing mating surface and exposed parts of the sealing ring. The thickness of the anti-rust oil should be ≤0.02mm to prevent the anti-rust oil from entering the sealing gap and damaging the fit between the lip and the mating surface. The cartridge valve sealing parts are tightly wrapped with a transparent plastic protective film to prevent impurities and dust from entering the sealing groove during transportation, storage and subsequent assembly, or external forces from scratching the sealing mating surface and displacing the sealing ring, so as to ensure that the gap compensation state of the X-shaped lip is maintained for a long time. During the subsequent assembly of cartridge valves, avoid applying axial or radial external forces to the sealing parts to ensure the coaxiality of the valve core, valve sleeve, and valve body, and prevent the recurrence of the compensated sealing gap. Furthermore, this method achieves multi-directional pressure oil sealing and adaptive gap compensation, solving the oil leakage problem at its root. This method utilizes the four-lip structure of the X-shaped lip sealing ring, allowing the four lips to precisely correspond to the four pressure oil action directions of the valve core axis and valve sleeve radial direction, achieving synchronous sealing of multi-directional pressure oil, breaking through the limitation of traditional sealing methods that can only seal in one direction; at the same time, the pressure compensation of the X-shaped lip sealing ring can reach 0.3~0.5mm, which can effectively fill the oil cavitation gap and production tolerance gap of 0.05~0.2mm. Combined with the multi-directional stepped pressure application method, the sealing ring lip undergoes adaptive elastic deformation with the action of pressure oil, completely fitting with the sealing surface, thus solving the oil leakage problem of cartridge valves at its root. Furthermore, this method precisely positions and controls the initial compression, significantly improving the assembly stability of the sealing structure. Through the use of a dedicated pressure block and precision testing, this method controls the radial offset of the X-shaped lip seal ring within the sealing groove to ≤0.03mm, ensuring accurate positioning of the seal ring without displacement. Simultaneously, the tightening torque is precisely set according to the diameter of the cartridge valve, stabilizing the initial compression of the four lips of the seal ring at 15%~20%, with a single lip compression deviation of ≤0.2mm. It also controls the frictional force of the valve core movement to 5~8N. This method achieves basic sealing through initial compression, compensates for the manufacturing tolerances of parts, and reserves reasonable elastic deformation space for subsequent pressure oil drive clearance compensation. This effectively prevents the seal ring from falling off, flanging, or failing due to excessive local compression during assembly and equipment operation, thus improving the overall stability of the sealing structure. Furthermore, this method employs a stepped pressure application and full-process testing and calibration to ensure the effectiveness and accuracy of gap compensation. This method uses a stepped synchronous pressure application to introduce hydraulic oil in four directions, increasing the pressure by 5 MPa each time and holding it for 5 minutes. This ensures that the sealing ring lip deforms uniformly with increasing pressure, avoiding compensation failure caused by localized deformation. The pressure is held for 30 minutes at 1.5 times the rated working pressure of the cartridge valve, with pressure fluctuation controlled to ≤±0.5 MPa, allowing the lip to fully complete deformation compensation and remain stable. Simultaneously, leak detection using the soap bubble method, leakage detection (≤0.01 mL / min), and valve core friction re-inspection are used to verify the compensation effect from all dimensions. If deviations occur, the tightening torque can be fine-tuned for re-compensation, ensuring the gap compensation effect meets the standards. This solves the problems of traditional sealing compensation lacking testing and having uncontrollable effects. Furthermore, this method enables successful one-time assembly of the cartridge valve sealing components, significantly reducing production and maintenance costs. From sealing surface inspection and sealing ring adaptation to positioning installation, pressure compensation, and effect testing, this method has established precise parameter standards and standardized operating procedures for each step. Strict precision control and effect verification are carried out throughout the process, ensuring a 100% first-time assembly pass rate for the cartridge valve sealing components. It completely avoids the repeated disassembly and rework caused by oil leakage problems in traditional sealing processes, greatly reducing labor and material losses caused by rework. At the same time, it improves the online assembly efficiency of hydraulic cartridge valves and reduces overall production and maintenance costs. Furthermore, this method incorporates compensation and protective measures to ensure the long-term maintenance of the sealing compensation effect. For cartridge valve assemblies that meet the compensation standards, this method applies a thin layer of anti-rust oil (thickness ≤0.02mm) and wraps them with a transparent plastic protective film to protect the sealing parts, preventing impurities from entering the sealing groove during transportation and storage, external forces from scratching the sealing mating surface, or causing the sealing ring to shift. At the same time, it requires that axial and radial external forces be avoided on the sealing parts during subsequent assembly to ensure the coaxiality of the valve core, valve sleeve, and valve body, prevent the recurrence of the compensated sealing gap, and ensure the long-term maintenance of the gap compensation state of the X-shaped lip, thereby improving the durability of the cartridge valve's sealing performance and the overall service life of the hydraulic system. Furthermore, this method features a standardized operating procedure, is compatible with existing production systems, and has strong feasibility for implementation. Each operation step in this method has clear parameter indicators and execution requirements, eliminating the need for complex specialized equipment. The gap detector, torque wrench, and hydraulic test bench used are all conventional equipment in the production of hydraulic cartridge valves. The sealing ring can be directly pressed into the sealing groove to complete the installation without the need for additional sealing auxiliary parts, simplifying the operation process and making it easy for on-site workers to execute. It can be directly adapted to the existing online assembly production system of hydraulic cartridge valves, resulting in low process modification costs and strong feasibility for implementation.

[0022] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for compensating the X-shaped lip gap of a cartridge valve multi-directional pressure oil seal, comprising: step 1: gap detection and sealing ring adaptation at the sealing mating surface; step 2: pretreatment of the sealing surface and sealing groove; step 3: positioning and installation of the X-shaped lip sealing ring and setting of the initial compression amount; step 4: stepwise pressure application of multi-directional pressure oil and adaptive gap compensation of the X-shaped lip; step 5: gap compensation effect detection and calibration; and step 6: compensation shaping and sealing protection, characterized in that: Step 5: Gap compensation effect detection and calibration includes step 501 leakage detection, step 502 performance re-inspection and step 503 deviation calibration; Step 1: Detection of the gap between the sealing surfaces and fitting of the sealing ring; A high-precision gap detector is used to perform full-dimensional inspection of the sealing surfaces of the valve core, valve sleeve and valve body of the cartridge valve. The inspection accuracy is ≤0.01mm. The focus is on inspecting the gaps caused by oil cavitation and the fit gaps caused by the manufacturing tolerance of the parts. The gap values ​​in each direction are recorded to ensure that the gaps to be compensated are ≤0.2mm (parts that exceed this range need to be repaired first). Based on the dimensions of the sealing groove (groove width 8±0.02mm, groove depth 4.5±0.01mm) and the measured gap value, a suitable X-shaped lip sealing ring is selected, and the elasticity of the sealing ring is tested: at a normal temperature of 25℃, a radial tensile force is applied to the sealing ring to ensure that there is no permanent deformation when its elongation rate is ≤15%. At the same time, the four lips of the sealing ring are checked for missing glue, cracks, and deformation to ensure that it has sufficient elastic deformation compensation capacity.

2. The method for compensating the X-shaped lip gap of the multi-directional pressure oil seal of the cartridge valve according to claim 1, characterized in that: Step 2: Pre-treatment of the sealing surface and sealing groove; Use a dust-free cleaning cloth soaked in analytical grade anhydrous ethanol to repeatedly wipe the sealing surfaces of the valve core, valve sleeve, and valve body, as well as the inner wall of the sealing groove, to remove surface oil, iron filings, and processing dust impurities. Wipe along the grain of the sealing surface to avoid leaving any fiber residue on the cleaning cloth. After wiping, place the sealing surface and sealing groove in a dry environment at room temperature and let them air dry naturally for no less than 5 minutes. Do not use blowing or heating to accelerate the drying process, as this may cause the sealing surface to deform due to temperature differences and damage the gap reference. If there are slight scratches with a depth of <0.05mm on the sealing surface, gently polish them along the grain with 800# metallographic sandpaper. After polishing, wipe clean again with anhydrous ethanol. After polishing, check the surface roughness of the sealing surface to ensure Ra≤0.8μm.

3. The method for compensating the X-shaped lip gap of the multi-directional pressure oil seal of a cartridge valve according to claim 1, characterized in that: Step 3: Positioning and installing the X-shaped lip sealing ring and setting the initial compression amount; Apply a thin layer of hydraulic grease evenly to the four lips and outer circumference of the X-shaped lip seal ring, with a grease application amount ≤ 0.5 g / cm². 2 This is to prevent excessive grease buildup from creating additional gaps and affecting the sealing and compensation effect; The sealing ring is slowly embedded into the sealing groove using a pressing method. A special pressure block is used to apply force evenly along the circumference of the sealing ring to ensure that the sealing ring is completely fitted to the inner wall of the sealing groove without wrinkles or folds. After installation, the four lips of the sealing ring are precisely aligned with the four directions of pressure oil action: the axial direction of the valve core, the radial direction of the valve sleeve, the circumferential direction of the valve body, and the oblique direction of the valve core-valve sleeve mating surface. The radial offset of the sealing ring is checked to be ≤0.03mm to prevent compensation failure caused by positioning deviation. Align the valve sleeve and valve body with the pre-installed sealing ring according to the assembly standard, ensuring coaxiality ≤0.05mm. Then slowly insert the valve core along the central axis and tighten it according to the valve diameter using a torque wrench: DN10 80±5N・m, DN15 95±5N・m, DN20 110±5N・m, DN25 120±5N・m. After tightening, check the initial compression of the four lips of the sealing ring to ensure that the compression is stable at 15%~20% and the single lip compression deviation is ≤0.02mm. The initial compression achieves basic sealing, while controlling the friction of the valve core movement at 5~8N to compensate for the manufacturing tolerance of the parts and reserve elastic deformation space for clearance compensation of subsequent pressure oil drive.

4. The method for compensating the X-shaped lip gap of the multi-directional pressure oil seal of a cartridge valve according to claim 1, characterized in that: Step 4: Multi-directional pressure oil stepped pressurization and X-shaped lip adaptive clearance compensation; Connect the cartridge valve assembly that has completed initial compression to the hydraulic test bench, seal the test pipeline to ensure that there is no external leakage in the pipeline, and reserve pressure oil input ports in four directions: valve core axial direction, valve sleeve radial direction, valve body circumferential direction, and valve core-valve sleeve mating surface oblique direction. Hydraulic oil is introduced in four directions using a stepped synchronous pressure method, with each pressurization increasing by 5 MPa and holding the pressure for 5 minutes after each increase. The elastic deformation of the X-shaped lip is observed to ensure that the lips in each direction deform uniformly with increasing pressure, without any local over-compression. The pressure is gradually increased to 1.5 times the rated working pressure of the cartridge valve (31.5 MPa). During this process, the sealing ring is subjected to multi-directional pressure oil, and its inner lip undergoes adaptive elastic deformation. The amount of deformation matches the gap of the sealing mating surface, achieving precise filling and compensation for cavitation gaps and tolerance gaps. Hold the pressure at 31.5MPa for 30 minutes, keeping the hydraulic system pressure fluctuation ≤±0.5MPa, to ensure that the X-shaped lip fully completes deformation compensation and remains stable, so that the lip and the sealing surface are completely fitted together, eliminating all effective gaps.

5. The method for compensating the X-shaped lip gap of the multi-directional pressure oil seal of a cartridge valve according to claim 1, characterized in that: Step 501 Leakage detection: During the pressure holding process, the soap bubble method is used to check for leaks at each sealing joint surface. The soap bubble solution is evenly applied to the joint surface, and no bubbles are generated, which means there is no leakage. After the pressure holding is completed, the leakage of the system is checked to ensure that the leakage is ≤0.01mL / min.

6. The method for compensating the X-shaped lip gap of the multi-directional pressure oil seal of a cartridge valve according to claim 1, characterized in that: Step 502 Performance retest: Slowly depressurize to normal pressure and test the friction force of the valve core movement to ensure that the friction force is still within the range of 5~8N. Avoid excessive deformation of the lip, which may cause excessive friction force and valve core jamming, or excessive friction force, which may cause the sealing ring to loosen.

7. The method for compensating the X-shaped lip gap of the multi-directional pressure oil seal of a cartridge valve according to claim 1, characterized in that: Step 503 Deviation calibration: If slight leakage or incomplete gap compensation is found, finely adjust the original tightening torque by ±5 N·m, and repeat step four for stepped pressure compensation. Hold the pressure for 10 minutes and test again until the compensation effect meets the standard.

8. The method for compensating the X-shaped lip gap of the multi-directional pressure oil seal of a cartridge valve according to claim 1, characterized in that: Step 6: Compensation shaping and sealing protection; For cartridge valve assemblies that meet the compensation requirements, apply a thin layer of anti-rust oil evenly to each sealing mating surface and exposed parts of the sealing ring. The thickness of the anti-rust oil should be ≤0.02mm to prevent the anti-rust oil from entering the sealing gap and damaging the fit between the lip and the mating surface. The cartridge valve sealing parts are tightly wrapped with a transparent plastic protective film to prevent impurities and dust from entering the sealing groove during transportation, storage and subsequent assembly, or external forces from scratching the sealing mating surface and displacing the sealing ring, so as to ensure that the gap compensation state of the X-shaped lip is maintained for a long time. During the subsequent assembly of cartridge valves, avoid applying axial or radial external forces to the sealing parts to ensure the coaxiality of the valve core, valve sleeve, and valve body, and prevent the recurrence of the compensated sealing gap.