A hydraulic cylinder based on additive strengthening

Abstract

The present invention discloses a hydraulic cylinder based on additive strengthening, which comprises a cylinder body, a piston rod, a piston, a guide sleeve and a pressure plate assembly. The cylinder body includes a cylinder barrel and a cylinder bottom. An anti-loosening block is embedded at the rear end of the piston rod and the piston. A retaining ring and a sealing ring are provided at the joint of the piston and the piston rod. A piston seal and a piston guide ring are provided on the outer edge of the piston. A static seal is provided between the guide sleeve and the cylinder barrel. A piston rod guide ring, a Struthers seal, a rod seal and a dust ring are provided between the guide sleeve and the piston rod. A copper alloy cladding layer is provided on the sliding surface of the inner wall of the cylinder barrel. Ferroalloy cladding layers are provided at the joint of the inner wall of the cylinder barrel and the guide sleeve, on the outer side wall of the cylinder barrel and on the outer side wall of the cylinder bottom. A nickel-chromium alloy cladding layer is provided on the outer surface of the piston rod. A copper-plated passivation layer is provided on the outer surface of the piston. The hydraulic cylinder of the present invention has high structural stability, good bonding between the main material and the strengthening layer of the surface additive, good mechanical properties and corrosion resistance, and improves the service life of the hydraulic cylinder.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydraulic cylinders, and particularly relates to a hydraulic cylinder based on additive strengthening. Background Technique

[0002] The shearer is one of the important equipment for coal mining, and its safe and reliable operation is related to whether the coal output of the mine can be completed as planned. Therefore, it is required that all components of the shearer operate reliably and reach the best operating state. The cutting and lifting hydraulic cylinder of the shearer (hereinafter referred to as the hydraulic cylinder) is a crucial component on the shearer, used to adjust the lifting of the cutting arm of the shearer so that the cutting drum reaches the required mining height and undercut amount. Its operation reliability is affected by many factors such as coal seam hardness, its own material, manufacturing accuracy, processing technology, use and maintenance, and overhaul. The hydraulic cylinder mainly consists of a cylinder body, a piston rod, a guide sleeve, and related accessories such as a sealing assembly, and the power comes from the hydraulic system of the shearer. The coal cutting operation of the shearer is a dynamic process. The hydraulic cylinder is subjected to axial thrust or tensile force, and is prone to oil leakage and cylinder head pull-off. In some cases, there will also be failures such as fracture and the hydraulic cylinder pressure relief cannot be self-locked. In order to reduce the maintenance difficulty and improve the performance of the hydraulic cylinder, the hydraulic cylinder needs to be improved by a reasonable method to improve the quality of the hydraulic cylinder and reduce its damage rate.

[0003] Affected by factors such as the usage environment conditions and processing technology, the main fault of the shearer hydraulic cylinder is oil leakage. The manifestations of the oil leakage fault are as follows: (1) The chromium plating layer of the piston rod is damaged, and the hydraulic oil leaks from the damaged chromium plating layer; (2) The dust ring leaks. Because the dust ring protrudes, larger foreign objects enter the piston rod oil seal from the protruding part of the dust ring, causing the oil seal to fail and leak oil. In addition, problems such as the fracture of the guide sleeve connection bolt and the piston rod fracture may also occur in the hydraulic cylinder. Regarding the oil leakage problem, the patent with the application number CN201911170690.4 discloses a hydraulic cylinder that can effectively prevent the loss of hydraulic oil, including: an oil cylinder housing, a hydraulic connector, a telescopic rod fixing part, and a telescopic rod. A pushing component is arranged between the telescopic rod fixing part and the oil cylinder housing. When hydraulic oil is injected into the interior of the oil cylinder housing, the oil pressure pushes the telescopic rod fixing part and drives the pushing component to move inward towards the telescopic rod fixing part at the same time. The pushing component synchronously pushes the linkage push rod and the linkage push block to move to the right, and the linkage push block squeezes the linkage component on the right side for compression. After the linkage component on the right side is compressed, it synchronously pushes the sealing rings and the oil blocking rings on both sides to abut against the inner wall of the oil cylinder housing; Although this method improves the sealing performance between the telescopic rod fixing part and the oil cylinder housing during the movement process, the wear problem caused by long-term use has not been solved, and the oil leakage problem caused by wear also follows. Regarding the piston rod fracture problem, the patent with the application number CN201110410609.2 discloses a method for surface nano-strengthening of the slender piston rod of a hydraulic cylinder, which uses the combined energy of mechanical energy generated by the high-frequency vibration of the ball and thermal energy with a temperature slightly higher than room temperature to grind, strengthen, and perform micro-deformation treatment on the surface of the piston rod without abrasive; Although this method can increase the yield point and hardness of the material surface, it will reduce the plasticity of the surface layer metal deformation, and if the internal stress generated is unevenly distributed, local stress concentration will also occur, resulting in fatigue damage.

[0004] The performance requirements of different parts of a hydraulic cylinder are different during operation. If the same material is used to prepare the whole part, it may result in weak performance in some parts and shorten the service life of the hydraulic cylinder. At the same time, in order to improve the performance, choosing a material with better performance to prepare the whole part will increase the input of material cost. Additive strengthening is a method that uses electrochemistry, laser beam, electron beam, plasma or ion beam to deposit materials layer by layer to directly form a cladding layer or coating layer on the surface of the part, so as to achieve the purpose of strengthening the surface performance of the part and improving the service life of the part. At present, the commonly used additive strengthening technologies include electroplating deposition technology, plasma cladding technology and laser cladding technology. Electroplating deposition technology is to reduce metal ions in the plating solution into metal atoms and deposit them on the metal surface under the condition of low-temperature medium by using the principle of electrolytic ion replacement. This method has high efficiency and low cost, but the environmental pollution is relatively serious. Plasma cladding technology has stable process and low cost, but its heat input is large, which is easy to cause deformation of the part, and slag inclusion and porosity are easy to appear in the overlap of the cladding layer. Laser cladding technology has concentrated energy, small heat input, almost no deformation of the workpiece, smooth appearance of the cladding layer, and the service life of laser cladding is relatively longer than that of plasma cladding, but the equipment investment cost is high and the technical threshold is high. How to improve the service performance of the hydraulic cylinder by using additive strengthening is an urgent problem to be studied and solved at present. Summary of the Invention

[0005] Based on the deficiencies of the prior art, the present invention provides a hydraulic cylinder based on additive strengthening, which improves the service performance and service life of the hydraulic cylinder by improving the structure and material of the hydraulic cylinder.

[0006] In order to achieve the above-mentioned invention purpose, a hydraulic cylinder based on additive strengthening is provided as follows and is realized through the following steps:

[0007] A hydraulic cylinder based on additive strengthening, comprising a cylinder block and a piston rod reciprocating along the cylinder block. Taking the direction in which the piston rod extends as the front, a guide sleeve and a pressure plate assembly are fixedly installed at the front end of the cylinder block. The front end of the piston rod passes through the guide sleeve and extends out of the pressure plate assembly. A piston is sleeved at the rear end of the piston rod. The cylinder block includes a cylinder barrel and a cylinder bottom. The cylinder bottom includes a bottom plate connected to the rear end of the cylinder barrel. Ear plates extend backward from both the upper and lower ends of the bottom plate. Mounting holes penetrating up and down are provided on the ear plates, and wear-resistant sleeves are fixed in the mounting holes. Anti-loosening blocks symmetrically arranged up and down are embedded at the rear end of the piston rod and the piston. The anti-loosening blocks are fixedly connected to the piston and are abutted against the rear end of the piston rod. A retaining ring and a sealing ring are installed at the joint between the front part of the piston and the piston rod. A piston seal extending in the circumferential direction and several piston guide rings are embedded on the outer edge of the piston. A static seal is provided between the outer edge of the guide sleeve and the inner wall of the cylinder barrel. Several piston rod guide rings are installed between the inner wall of the guide sleeve and the piston rod. A stepped seal, a rod seal and a dust seal are sequentially arranged between the inner wall of the guide sleeve and the piston rod from the rear to the front. Among them, a copper alloy cladding layer for improving surface wear resistance and corrosion resistance is provided on the sliding surface of the inner wall of the cylinder barrel. Ferroalloy cladding layers for increasing surface hardness are provided at the joint between the inner wall of the cylinder barrel and the guide sleeve, on the outer side wall of the cylinder barrel and on the outer side wall of the cylinder bottom. A nickel-chromium alloy cladding layer is provided on the outer surface of the piston rod. Copper-plated passivation layers are provided on the outer surfaces of the piston and the guide sleeve.

[0008] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0009] Through the mutual cooperation among the piston rod, the piston, the cylinder barrel and the guide sleeve, and by setting a retaining ring, a sealing ring, a stepped seal, a static seal, a rod seal, etc., the sealing performance of the hydraulic cylinder is improved, and the situation of oil leakage during the use of the hydraulic cylinder is avoided. For the sliding surface of the inner wall of the cylinder barrel, the surface wear resistance and corrosion resistance are improved through the copper alloy cladding layer. For the joint between the inner wall of the cylinder barrel and the guide sleeve, the outer side wall of the cylinder barrel and the outer side wall of the cylinder bottom, the surface hardness is increased through the ferroalloy cladding layer. By providing a nickel-chromium alloy cladding layer on the outer surface of the piston rod, the corrosion resistance and anti-deformation performance of the piston rod are improved. By providing a copper-plated passivation layer on the outer surface of the piston, the corrosion resistance of the piston is improved, thereby greatly extending the service life of the hydraulic cylinder.

[0010] To ensure the structural stability of the hydraulic cylinder, the piston rod includes a threaded rod portion, a smooth rod portion, and an earring portion that are sequentially connected from back to front. The diameter of the threaded rod portion is smaller than that of the smooth rod portion, and a tapered surface transition is adopted between the threaded rod portion and the smooth rod portion. A threaded hole portion and a through hole portion are coaxially provided inside the piston. The threaded hole portion is adapted to be connected with the threaded rod portion, and the through hole portion is adapted to be connected with the smooth rod portion. Grooves for embedding anti-loosening blocks are provided at the threaded rod portion and the threaded hole portion. A first fastener is installed on the anti-loosening block, and the anti-loosening block is firmly installed on the piston through the first fastener. The axial center line of the first fastener is parallel to the axial center line of the piston rod. An annular groove is provided in the middle of the through hole portion along the circumferential direction, and the retaining ring and the sealing ring are embedded in the annular groove. A number of second fasteners are evenly spaced along the circumferential direction on the guide sleeve. The axial center line of the second fastener is parallel to the axial center line of the cylinder barrel. The rear end of the second fastener is firmly connected to the front end of the cylinder barrel, and the guide sleeve is firmly installed at the front end of the cylinder barrel through the second fastener. The rear part of the guide sleeve is inserted into the front port of the cylinder barrel, and the inner diameter of the cylinder barrel at the position where the guide sleeve is installed is larger than the inner diameter of the sliding surface of the cylinder barrel inner wall. A valve block is provided at the rear end of the cylinder barrel, a hydraulic oil port is provided on the valve block, and a hydraulic oil flow channel is provided inside the cylinder barrel. The hydraulic oil flow channel is communicated with the hydraulic oil port, and the reciprocating movement of the piston rod and the piston is realized by controlling the hydraulic oil inside the cylinder barrel. The pressing plate assembly includes two semi-circular pressing plates arranged opposite to each other left and right. The semi-circular pressing plates are firmly installed on the front side of the guide sleeve. A steel pipe is welded to the front side of each semi-circular pressing plate, and the steel pipes on the left and right semi-circular pressing plates are arranged symmetrically left and right. The semi-circular pressing plates and the steel pipes are all made of 27SiMn material.

[0011] To improve the precision of the reciprocating movement of the piston rod in the hydraulic cylinder, a stroke sensor is built into the cylinder body. The stroke sensor includes a sensor rod. A cavity for accommodating the sensor rod is axially provided at the center of the piston rod. The sensor rod passes through the sensor gland and extends into the cavity. A magnetic ring is embedded at the rear end of the cavity, and the magnetic ring is sleeved on the sensor rod. The sensor gland is embedded at the center of the front side of the bottom plate. The sensor gland is inserted and connected with the sensor rod. A positioning shoulder is provided at the rear end of the sensor rod, and the rear end of the sensor gland abuts against the positioning shoulder. A connecting wire is provided at the rear end of the sensor rod. The connecting wire is located inside the bottom plate and extends along a direction perpendicular to the sensor rod to the outer side of the bottom plate. An aviation plug bracket for plugging the end of the connecting wire is provided on the outer side of the bottom plate. A through channel is provided inside the aviation plug bracket. A cover plate for blocking the port is provided at one port of the channel, and a positioning sleeve is installed at the other port of the channel. A part of the positioning sleeve is inserted into the channel, and the other part of the positioning sleeve is inserted into the bottom plate. The connecting wire is inserted and connected with the positioning sleeve.

[0012] To enable each component of the hydraulic cylinder to meet the basic required performance requirements, the cylinder bottom and the cylinder barrel are both made of 30CrMnSi material, the wear-resistant sleeve is made of GCr15 material, the piston rod, the piston and the guide sleeve are all made of 42CrMo material, and the lock washer is made of 30CrMnSiA material. The nickel-chromium alloy cladding layer is formed by cladding with nickel-chromium alloy welding wire; the thicknesses of the copper alloy cladding layer, the ferroalloy cladding layer and the nickel-chromium cladding layer are all 0.5 - 2.0 mm; the thickness of the copper-plated passivation layer is 0.03 - 0.05 mm.

[0013] To improve the wear resistance and corrosion resistance of the cylinder body surface, the copper alloy cladding layer is formed by cladding with copper alloy welding wire, and the copper alloy welding wire includes the following components in mass percentage: Ni 4.5 - 6.0%, Al 7.0 - 9.0%, Fe 2.2 - 4.0%, Mn 1.0 - 2.0%, Ti 0.2 - 0.35%, Gd 0.02 - 0.05%, As 0.02 - 0.04%, C < 0.03%, and the balance is Cu; to improve the mechanical properties of the cylinder body surface, the ferroalloy cladding layer is formed by cladding with ferroalloy welding wire, and the ferroalloy welding wire includes the following components in mass percentage: Ni 4.0 - 5.0%, Mo 2.0 - 3.0%, Cr 17.0 - 19.0%, Mn 0.35 - 0.75%, Si 0.35 - 0.4%, C ≤ 0.02%, P ≤ 0.02%, S ≤ 0.02%, and the balance is Fe.

[0014] To further improve the hardness of the copper alloy cladding layer and the ferroalloy cladding layer and also improve the lubricity of the welding wire during the cladding process, a nano-composite coating is coated on the surface of the copper alloy welding wire and the surface of the ferroalloy welding wire. The nano-composite coating is made of a coating liquid, and the coating liquid includes the following components in mass percentage: intermetallic compound powder 5.4 - 7.2%, nano-ceramic powder 1.8% - 3.6%, nano-conductive carbon black 10 - 15%, nickel-based alloy powder 8 - 15%, titanate accelerator 1 - 3%, and the balance is a base liquid. Among them, the intermetallic compound powder is powdered (Ti 1-x Ta x )5Si3, and in (Ti 1-x Ta x )5Si3, x is 0.2 - 0.4; the nano-ceramic powder is Si3N4 powder with a particle size of 15 - 30 nm; the nickel-based alloy powder is selected as nickel-based self-fluxing alloy powder; the titanate accelerator is selected as n-butyl titanate; the base liquid is one or more of alcohol solvents, alcohol ether solvents, ester solvents and ketone solvents.

[0015] To ensure the sealing performance of the sealing structure, the retaining ring is of the N0300-90 type, the sealing ring is an O-ring made of NBR90 material, the piston seal is made of a TPPE / NBR / POM composite material, the piston guide ring and the piston rod guide ring are both made of POM material, the static seal, the rod seal and the dust ring are all made of PU material, and the Struthers seal is made of PTFE / NBR material.

[0016] The hydraulic cylinder of the present invention has high structural stability, and the material selection takes into account both performance and cost. The bonding between the main material and the strengthened layer of surface additive manufacturing is good, correspondingly improving the mechanical properties and corrosion resistance of the hydraulic cylinder, ensuring the use safety and service life of the hydraulic support, extending the maintenance cycle of the hydraulic cylinder, and having good economic benefits. Brief Description of the Drawings

[0017] Figure 1 is a schematic structural diagram of the cylinder body of the present invention;

[0018] Figure 2 is Figure 1 the front view sectional view of;

[0019] Figure 3 is Figure 1 the top view of;

[0020] Figure 4 is Figure 1 the schematic structural diagram of the middle cylinder body in;

[0021] Figure 5 is Figure 4 the front view sectional view of;

[0022] Figure 6 is Figure 5 the sectional view along the A-A line in;

[0023] Figure 7 is Figure 4 the top view of;

[0024] Figure 8 is Figure 2 the schematic structural diagram of the piston rod in;

[0025] Figure 9 is Figure 8 the top view of;

[0026] Figure 10 is Figure 9 the partial enlarged view at I in;

[0027] Figure 11 is Figure 9 the left view of;

[0028] Figure 12is Figure 2 Structural schematic diagram of the piston in

[0029] Figure 13 is Figure 12 Left view of

[0030] Figure 14 is Figure 2 Structural schematic diagram of the anti-loosening block in

[0031] Figure 15 is Figure 14 Left view of

[0032] Figure 16 is Figure 2 Structural schematic diagram of the guide sleeve in

[0033] Figure 17 is Figure 16 Right view of

[0034] Figure 18 is Figure 1 Right view of the pressure plate assembly in

[0035] Figure 19 is Figure 18 Left view of

[0036] Figure 20 is Figure 2 Structural schematic diagram of the medium aviation plug bracket in

[0037] Figure 21 is Figure 19 Top view of

[0038] Figures 1 - 21Among them, each reference numeral is as follows: 1. First retaining ring; 2. Piston guide ring; 3. Magnetic ring; 4. Piston seal; 5. First static seal; 6. Second static seal; 7. Star seal; 8. Rod seal; 9. Piston rod guide ring; 10. Dust ring; 11. First screw; 12. Second screw; 13. Third screw; 14. Fourth screw; 15. Elastic washer; 16. Fifth screw; 17. Cylinder block; 1701. Cylinder barrel; 1702. Base plate; 1703. Ear plate; 1704. Mounting hole; 1705. Valve block; 1706. Hydraulic oil port; 1707. Hydraulic oil flow channel; 18. Sensor gland; 19. Piston rod; 1901. Threaded rod part; 1902. Smooth rod part; 1903. Earring part; 1904. Taper transition; 1905. Cavity; 1906. First mounting groove; 1907. Second mounting groove; 1908. Step hole; 1909. First groove; 20. Piston; 2001. Threaded hole part; 2002. Through hole part; 2003. Annular groove; 2004. Second groove; 21. Guide sleeve; 2101. Insertion part; 2102. Mounting part; 2103. First seal groove; 2104. Second seal groove; 2105. Third seal groove; 2106. Fourth seal groove; 22. Locking block; 2201. Block body; 2202. Counterbore; 23. Aviation plug bracket; 2301. Frame body; 2302. Mounting plate; 2303. Channel; 24. Positioning sleeve; 25. Wear-resistant sleeve; 26. Sensor rod; 27. Pressure plate assembly; 2701. Semi-circular pressure plate; 2702. Steel pipe; 28. Sealing ring; 29. Second retaining ring; 30. Cover plate. Detailed implementation mode

[0039] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following further elaborates on the present invention in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. For those without specific technologies or conditions noted in the embodiments, the technologies or conditions described in the literature in this field or the product specifications are followed.

[0040] Embodiment 1

[0041] As Figures 1 - 21 shown, a hydraulic cylinder based on additive strengthening includes a cylinder block 17 and a piston rod 19 that reciprocates along the cylinder block 17. Taking the direction in which the piston rod 19 extends as the front, a guide sleeve 21 and a pressure plate assembly 27 are fixedly installed at the front end of the cylinder block 17. The front end of the piston rod 19 passes through the guide sleeve 21 and extends out of the pressure plate assembly 27, and a piston 20 is sleeved on the rear end of the piston rod 19.

[0042] The cylinder block 17 includes a cylinder barrel 1701 and a cylinder bottom. The cylinder bottom includes a bottom plate 1702 connected to the rear end of the cylinder barrel 1701. Ear plates 1703 extend backward from both the upper and lower ends of the bottom plate 1702. Mounting holes 1704 penetrating through vertically are provided on the ear plates 1703, and wear-resistant sleeves 25 are fixed in the mounting holes 1704. A valve block 1705 is provided at the rear end of the cylinder barrel 1701. A hydraulic oil port 1706 is provided on the valve block 1705. A hydraulic oil flow passage 1707 is provided in the cylinder barrel 1701. The hydraulic oil flow passage 1707 communicates with the hydraulic oil port 1706. The reciprocating movement of the piston rod 19 and the piston 20 is realized by controlling the hydraulic oil in the cylinder barrel 1701.

[0043] The piston rod 19 includes a threaded rod portion 1901, a smooth rod portion 1902, and an earring portion 1903 connected in sequence from the rear to the front. The diameter of the threaded rod portion 1901 is smaller than that of the smooth rod portion 1902, and a tapered surface transition 1904 is adopted between the threaded rod portion 1901 and the smooth rod portion 1902. A threaded hole portion 2001 and a through hole portion 2002 are coaxially provided in the piston 20. The threaded hole portion 2001 is adapted to be connected with the threaded rod portion 1901, and the through hole portion 2002 is adapted to be connected with the smooth rod portion 1902. Anti-loosening blocks 22 symmetrically arranged up and down are embedded at the rear ends of the piston rod 19 and the piston 20. The anti-loosening blocks 22 include a block body 2201. Two counterbores 2202 are provided on the block body 2201. Elastic washers 15 and fourth screws 14 are installed at the counterbores 2202. The axial center line of the fourth screw 14 is parallel to the axial center line of the piston rod 19. A first groove 1909 is provided at the rear side of the threaded rod portion 1901, and a second groove 2004 is provided at the rear side of the piston 20. The first groove 1909 communicates with the second groove 2004 for embedding the anti-loosening blocks 22. The counterbores 2202 are located in the second groove 2004. The fourth screw 14 passes through the block body and is tightly connected to the piston 20. The anti-loosening blocks 22 are pressed against the bottom of the first groove 1909 to prevent the piston rod 19 from moving backward relative to the piston 20. An annular groove 2003 is provided in the middle of the through hole portion 2002 along the circumferential direction. A second retaining ring 29 and a sealing ring 28 are embedded and installed in the annular groove 2003. The outer edge of the piston 20 is embedded and installed with a piston seal 4 and three piston guide rings 2 extending along the circumferential direction. One of the piston guide rings 2 is located at the rear side of the piston seal 4, and the other two piston guide rings 2 are located at the front side of the piston seal 4.

[0044] The cylinder block 17 is internally provided with a stroke sensor. The stroke sensor includes a sensor rod 26. An axial cavity for accommodating the sensor rod 26 is provided at the center of the piston rod 19. The sensor rod 26 passes through the sensor gland and extends into the cavity 1905. The rear end of the sensor rod 26 is located within the bottom plate 1702. A sensor gland 18 is embedded at the center of the front side of the bottom plate 1702. The sensor gland 18 is inserted into the sensor rod 26. A positioning shoulder is provided at the rear end of the sensor rod 26. The rear end of the sensor gland 18 abuts against the positioning shoulder. The rear end of the sensor rod 26 is fixed within the bottom plate 1702 through the sensor gland 18. A stepped hole 1908 is axially provided at the rear end of the piston rod 19. The stepped hole 1908 is coaxially communicated with the cavity 1905. The stepped hole 1908 is used to accommodate the part of the sensor gland 18 protruding forward from the bottom plate 1702. A first installation groove 1906 and a second installation groove 1907 are provided in a circumferential direction at the junction of the stepped hole 1908 and the cavity 1905. A magnetic ring 3 is embedded in the first installation groove 1906, and the magnetic ring 3 is sleeved on the sensor rod 26. The second installation groove 1907 is located at the rear side of the first installation groove 1906. A first retaining ring 1 is embedded and installed in the second installation groove 1907. A connecting wire is provided at the rear end of the sensor rod 26. The connecting wire is located within the bottom plate 1702 and extends upward in a direction perpendicular to the sensor rod 26 to the upper side of the bottom plate 1702. A socket holder 23 for plugging the end of the connecting wire is provided on the upper side of the bottom plate 1702. The socket holder 23 includes a block-shaped frame body 2301. An installation plate 2302 extends backward from the bottom of the frame body 2301. A first screw 11 is installed on the installation plate 2302. The socket holder 23 is fixedly installed on the cylinder block through the first screw 11. A through channel 2303 is provided within the frame body 2301. The channel 2303 is in a right-angled shape. The upper port of the channel 2303 faces backward, and a cover plate 30 for blocking the port is provided at the upper port of the channel 2303. The cover plate 30 is installed on the frame body 2301 through a fifth screw 16. A positioning sleeve 24 is installed at the lower port of the channel. The upper part of the positioning sleeve 24 is inserted into the lower part of the channel 2303, and the lower part of the positioning sleeve 24 is inserted into the bottom plate 1702. The connecting wire is inserted into the positioning sleeve 24.

[0045] The guide sleeve 21 includes a plug-in part 2101 and an installation part 2102 connected to the front side of the plug-in part 2101. The plug-in part 2101 is inserted into the front port of the cylinder barrel 1701, and the inner diameter of the cylinder barrel 1701 at the installation position of the guide sleeve 21 is slightly larger than the inner diameter of the inner wall sliding surface of the cylinder barrel 1701; two circles of first sealing grooves 2103 are arranged along the circumferential direction on the outer edge of the plug-in part 2101, and a first static seal 5 (using a Y-ring type) and a second static seal 6 (using a dumbbell-ring type) are respectively arranged in the two circles of first sealing grooves 2103; four piston rod guide rings 9 are installed between the inner wall of the guide sleeve 21 and the piston rod 19. A second sealing groove 2104 and a third sealing groove 2105 are arranged along the circumferential direction in the middle of the inner wall of the guide sleeve 21. A Strut seal 7 is embedded and installed in the second sealing groove 2104, and a rod seal is embedded and installed in the third sealing groove 2105. A fourth sealing groove 2106 is arranged along the circumferential direction at the front end of the inner wall of the guide sleeve 21, and a dust seal 10 is installed in the fourth sealing groove 2106. The Strut seal 7, the rod seal and the dust seal 10 are located between the guide sleeve 21 and the piston rod 19, and the Strut seal 7, the rod seal 8 and the dust seal 10 are arranged from the back to the front along the axial direction of the guide sleeve 21; three of the four piston rod guide rings 9 are located behind the Strut seal 7, and the other piston rod guide ring 9 is located between the rod seal 8 and the dust plug. A number of second screws 12 are evenly spaced along the circumferential direction on the installation part 2102. The axial center line of the second screw 12 is parallel to the axial center line of the cylinder barrel 1701. The rear end of the second screw 12 is fixedly connected to the front end of the cylinder barrel 1701. The guide sleeve 21 is fixedly installed at the front end of the cylinder barrel 1701 through the second screw 12.

[0046] The pressure plate assembly 27 includes two semi-circular pressure plates 2701 arranged opposite to each other left and right. A number of third screws 13 are evenly spaced along the circumferential direction on the semi-circular pressure plate 2701. The rear end of the third screw 13 is fixedly connected to the front end of the guide sleeve 21. The semi-circular pressure plate 2701 is fixedly installed on the front side of the guide sleeve 21 through the third screw 13; two steel pipes 2702 are welded on the front side of each semi-circular pressure plate 2701, and the steel pipes 2702 on the left and right semi-circular pressure plates 2701 are arranged symmetrically left and right.

[0047] To enable each component of the hydraulic cylinder to meet the basic required performance requirements, the cylinder bottom and the cylinder barrel 1701 are both made of 30CrMnSi material, and the wear-resistant sleeve 25 is made of GCr15 material; a copper alloy cladding layer for enhancing surface wear and corrosion resistance is provided on the sliding surface of the inner wall of the cylinder barrel 1701, and ferroalloy cladding layers for increasing surface hardness are provided at the junction of the inner wall of the cylinder barrel 1701 and the guide sleeve 21, on the outer side wall of the cylinder barrel 1701, and on the outer side wall of the cylinder bottom. The copper alloy cladding layer and the ferroalloy cladding layer are both formed by cold arc cladding. After cold arc cladding, the cylinder block 17 is subjected to heat treatment (the heat treatment is controlled as follows: loading into the furnace and heating up to 730°C, holding for 2 h, cooling down to 510°C and holding for 1 h, and then cooling in the furnace to 300°C and taking out for air cooling).

[0048] The piston rod 19, the piston 20, and the guide sleeve 21 are all made of 42CrMo material. The whole piston rod 19 is subjected to quenching and tempering treatment after forging, and the hardness after tempering is 260 - 280 HB. An outer surface of the piston rod 19 is successively provided with a nickel-chromium alloy cladding layer outward. The nickel-chromium alloy cladding layer is formed by cold arc cladding using a nickel-chromium alloy welding wire (ERNiCr-3). The cladding process must be a low-temperature process, and the temperature of the piston rod 19 substrate does not exceed 250°C to prevent deformation of the piston rod 19 and changes in the internal structure, and the mechanical properties of the piston rod 19 substrate are not reduced. The surface hardness of the nickel-chromium alloy cladding layer formed by cladding is 45 - 50 HRC. Both the piston 20 and the guide sleeve 21 are forgings, and are subjected to quenching and tempering treatment after machining. The outer surfaces of the piston 20 and the guide sleeve 21 are both provided with a copper-plated passivation layer (that is: copper plating and passivation, which can be achieved by using conventional technical means in the prior art. The copper plating and passivation processes are not the innovations of the present invention, so they will not be described in detail). The anti-loosening block 22 is made of 30CrMnSiA material. The semi-circular pressing plate 2701 and the steel pipe 2702 are both made of 27SiMn material.

[0049] Among them, the thicknesses of both the copper alloy cladding layer and the ferroalloy cladding layer are 0.8 - 1 mm; the thickness of the tin bronze coating is 0.02 - 0.035 mm, the thickness of the hard chromium coating ≥0.03 mm, and the total thickness of the tin bronze coating and the hard chromium coating is 0.05 - 0.08 mm; the thickness of the copper-plated passivation layer is 0.03 - 0.05 mm.

[0050] To ensure the sealing performance of the hydraulic cylinder, the first retaining ring 1 is made of 65Mn material, the second retaining ring 29 is an N0300-90 type retaining ring, the sealing ring 28 is an O-ring made of NBR90 material, the piston seal 4 is made of a TPPE / NBR / POM composite material, the piston guide ring 2 and the piston rod guide ring 9 are both made of POM material, the first static seal 5, the second static seal 6, the rod seal 8, and the dust ring 10 are all made of PU material, and the stepped seal 7 is made of a PTFE / NBR material.

[0051] The rated pressure of the rod chamber of the above hydraulic cylinder is 40 MPa, the rated pressure of the rodless chamber is 30 MPa, the test pressure is 48 MPa, and it is kept pressurized for 10 minutes without leakage at 1.5 times the working pressure.

[0052] Example 2

[0053] In order to improve the wear and corrosion resistance of the surface of the cylinder block 17, the copper alloy cladding layer is formed by cladding with a copper alloy welding wire. The copper alloy welding wire includes the following components in mass percentage: Ni 4.5 - 6.0%, Al 7.0 - 9.0%, Fe 2.2 - 4.0%, Mn 1.0 - 2.0%, Ti 0.2 - 0.35%, Gd 0.02 - 0.05%, As 0.02 - 0.04%, C < 0.03%, and the balance is Cu; in order to improve the mechanical properties of the surface of the cylinder block 17, the ferroalloy cladding layer is formed by cladding with a ferroalloy welding wire. The ferroalloy welding wire includes the following components in mass percentage: Ni 4.0 - 5.0%, Mo 2.0 - 3.0%, Cr 17.0 - 19.0%, Mn 0.35 - 0.75%, Si 0.35 - 0.4%, C ≤ 0.02%, P ≤ 0.02%, S ≤ 0.02%, and the balance is Fe.

[0054] More preferably, the preparation steps of the copper alloy welding wire are as follows:

[0055] (1) Weigh the raw materials according to the mass percentages of each component: Ni 5.2%, Al 8.1%, Fe 2.8%, Mn 1.37%, Ti 0.28%, Gd 0.03%, As 0.03%, C < 0.03%, and the balance is Cu; among them, Ni / Fe = 1.857. The raw materials can be pure metals or intermediate alloys.

[0056] (2) Melting: Place the raw materials in a vacuum melting chamber, heat them to 1100 °C with medium-frequency induction, and melt for 45 minutes to obtain an alloy melt. Continuously introduce argon into the alloy melt for 15 minutes under the insulation state to obtain a copper alloy liquid.

[0057] (3) Casting - hot rolling: Heat the copper alloy liquid obtained in step (2) to 1300 °C, and form a copper alloy bar with a diameter of 40 mm through horizontal continuous casting. Control the rolling-in temperature to be 450 °C, and perform 3 times of hot continuous rolling. The total reduction rate of the outer diameter of the hot continuous rolling is 75%, and the rolling speed of the hot continuous rolling is 2 m / s. Then pickle the surface to remove the oil and impurities on the surface to obtain a copper alloy rod with a diameter of 10 mm; among them, D0 is the rolling-in diameter (unit: mm), D i is the rolling-out diameter (unit: mm);

[0058] (4) Solution-aging treatment: In a vacuum furnace, heat the copper alloy rod to 910 °C with the furnace, hold for 1.5 h, cool it in a quenching medium to below 60 °C, and then air-cool to room temperature; then, in the vacuum furnace again, heat it to 440 °C, hold for 2 h, cool with the furnace to below 100 °C, and then air-cool to room temperature to obtain a solution-strengthened rod;

[0059] (5) Phosphating treatment - cold drawing - intermediate annealing: After straightening, pickling, surface phosphating treatment and lubricating oil coating of the solution-strengthened rod obtained in step (4), perform single-mode drawing with a reduction rate of 17% per pass and a drawing speed of 1 m / s, and then perform multi-mode drawing with a reduction rate of 10% per die and a drawing speed of 2 m / s. When the cold deformation amount reaches 60 - 75% (total reduction rate > 40%) during single-mode drawing and multi-mode drawing, anneal in vacuum at 560 °C for 30 min and cool with the furnace. Do not perform vacuum annealing treatment at the end of multi-mode drawing; after cold drawing, size and scrape (scraping speed is 8 m / s, reduction is 0.02 mm) to obtain a copper alloy welding wire with a diameter of 1 mm (since there is vacuum heat treatment when preparing the nano-composite coating, no annealing treatment is performed after machining); where, D0 is the entry die diameter (unit: mm), D i is the exit die diameter (unit: mm);

[0060] Among them, the pickling uses an aqueous solution containing 100 g / L H2SO4, 40 g / L H2O2, 40 g / L ethanol and 0.2 g / L benzotriazole, and soak at room temperature for 30 s; the surface phosphating treatment uses a commercially available zinc-manganese series phosphating solution (AIR-XMA50), soak at room temperature for 5 min, and the phosphating film weight per unit area after surface phosphating treatment is about 5 g / m 2 ;

[0061] The cold drawing and intermediate annealing processes are controlled as follows:

[0062] Single-mode drawing: φ10 mm → φ8.30 mm → φ6.89 mm → φ5.72 mm → intermediate annealing → φ4.75 mm → φ3.94 mm → φ3.27 mm → intermediate annealing;

[0063] Multi-mode drawing: φ3.27 mm - φ2.94 mm - φ2.65 mm - φ2.38 mm - φ2.14 mm - φ1.93 mm; intermediate annealing; φ1.93 mm - φ1.74 mm - φ1.56 mm - φ1.40 mm - φ1.26 mm - φ1.13 mm - φ1.02 mm.

[0064] The yield strength of the above-prepared copper alloy welding wire is 789.6 MPa and the tensile strength is 1237.1 MPa.

[0065] More preferably, the preparation steps of the ferroalloy welding wire are as follows:

[0066] (1) Weigh the raw materials according to the mass percentages of each component: Ni 4.5%, Mo 2.5%, Cr 18.0%, Mn 0.6%, Si 0.38%, C ≤ 0.02%, P ≤ 0.02%, S ≤ 0.02%, and the balance is Fe. The raw materials can be pure metals or master alloys.

[0067] (2) Melting: Place the raw materials in a vacuum melting chamber, heat them to 1350 °C with medium-frequency induction, and melt for 45 minutes to obtain an alloy melt. Then, introduce argon into the alloy melt for 15 minutes under the insulation state to obtain a ferroalloy liquid.

[0068] (3) Casting-hot rolling: Control the temperature of the ferroalloy liquid at 1300 - 1350 °C, and form a ferroalloy bar with a diameter of 40 mm through horizontal continuous casting. Control the rolling-in temperature at 450 °C, and conduct three passes of hot continuous rolling. The total reduction rate of the outer diameter during hot continuous rolling is 75%, and the rolling speed of hot continuous rolling is 2 m / s. Then, pickle the surface to remove the oil and impurities on the surface to obtain a ferroalloy rod with a diameter of 10 mm.

[0069] (4) Full annealing: In a vacuum furnace, heat the ferroalloy rod to 950 °C along with the furnace, hold for 1 hour, cool along with the furnace to below 450 °C, and then air-cool to room temperature to obtain a refined rod.

[0070] (5) Cold drawing-intermediate annealing: After straightening, cleaning, and lubricating the refined rod, conduct multi-pass drawing. The reduction rate for each pass is 8 - 10% and the drawing speed is 1 m / s. When the cold deformation amount during the drawing process is greater than 65%, conduct vacuum annealing at 590 °C for 30 minutes and then cool along with the furnace. No annealing treatment is conducted at the end of the cold drawing. After cold drawing, size the diameter and scrape (the scraping speed is 8 m / s, scrape twice, and the reduction in diameter for each pass is 0.02 mm) to obtain a ferroalloy welding wire with a diameter of 2 mm (since there is vacuum heat treatment during the preparation of the nano-composite coating, no annealing treatment is conducted after machining).

[0071] The cold drawing and intermediate annealing processes are controlled as follows:

[0072] φ10 mm → φ9.0 mm → φ8.1 mm → φ7.29 mm → φ6.56 mm → φ5.90 mm → intermediate annealing → φ5.31 mm → φ4.78 mm → φ4.30 mm → φ,3.87 mm → φ3.48 mm → intermediate annealing → φ3.13 mm → φ2.88 mm → φ2.62 mm → φ2.41 mm → φ2.22 mm → φ2.04 mm.

[0073] The yield strength of the above-prepared ferroalloy welding wire is 1012.3 MPa, and the tensile strength is 1756.9 MPa.

[0074] Example 3

[0075] In order to further improve the hardness of the copper alloy cladding layer and the ferroalloy cladding layer, and also improve the lubricity of the welding wire during the cladding process, both the surface of the copper alloy welding wire and the surface of the ferroalloy welding wire are coated with a nano-composite coating (i.e., coated copper alloy welding wire / coated ferroalloy welding wire), and the mass percentage of the nano-composite coating in the coated copper alloy welding wire / coated ferroalloy welding wire is 0.8%.

[0076] The nano-composite coating is made from a coating solution, and the coating solution includes the following components in mass percentages: (Ti 0.75 Ta 0.25 )5Si3 powder 5.8%, nano-Si3N4 powder 2.7%, nano-conductive carbon black 12.5%, Ni60A powder 12%, tetrabutyl titanate 2%, and the balance is isopropanol.

[0077] Among them, the (Ti 0.75 Ta 0.25 )5Si3 is prepared by the following steps:

[0078] Weigh Ti powder, Ta powder and Si powder according to the molar ratio of the compounds, ball mill for 5 h in an argon atmosphere (the ball-to-material ratio during ball milling is 10:1, using anhydrous ethanol as the grinding aid, the ball milling speed is 400 r / min, and dry at 80 °C after ball milling), and cold isostatically press and form to obtain a massive material; in a vacuum melting chamber (the vacuum degree is less than 0.1 Pa), heat the massive material to melt, then cool down to 2180 °C and hold for 40 min, and use the gas atomization method to make powder (spray powder with argon at a pressure of 4 MPa), after collecting the powder, hold and temper at 450 °C for 3 h in an argon atmosphere, and then cool to room temperature, and sieve to obtain it.

[0079] The coating solution is prepared by the following steps:

[0080] Under a mixed atmosphere of carbon dioxide and argon, mix (Ti 0.75 Ta 0.25 )5Si3 powder, nano-Si3N4 powder (particle size about 20 nm), nano-conductive carbon black and Ni60A powder, and ball mill for 4 h (the ball-to-material ratio during ball milling is 12:1, using anhydrous ethanol as the grinding aid, the ball milling speed is 400 r / min, and dry at 70 °C after ball milling) to obtain a mixed powder; ultrasonically disperse the mixed powder and tetrabutyl titanate in isopropanol to obtain the coating solution.

[0081] The steps for forming a nano-composite coating on the surface of the copper alloy welding wire / ferroalloy welding wire are as follows:

[0082] Immerse the copper alloy welding wire / ferroalloy welding wire in an etchant (aqueous solution containing 3% H2SO4 and 4% citric acid) for surface treatment for 20 - 30 s (30 s for copper alloy welding wire and 20 s for ferroalloy welding wire). After cleaning and drying, apply the coating solution mechanically on the surface of the copper alloy wire. After drying, conduct vacuum heat treatment for 30 min (400 °C for copper alloy welding wire and 450 °C for ferroalloy welding wire). After furnace cooling, then wind and coil to obtain the coated copper alloy welding wire / coated ferroalloy welding wire.

[0083] The nano - composite coating improves the lubricity of the coated copper alloy welding wire / coated ferroalloy welding wire, reduces the wear of the coated copper alloy welding wire / coated ferroalloy welding wire on the contact tip. The copper alloy welding wire / ferroalloy welding wire coated with the nano - composite coating significantly reduces the wear rate of the contact tip aperture. Detect by continuous cold - arc cladding for 5 h. The wear rates of the contact tip aperture for the copper alloy welding wire and the ferroalloy welding wire are about 18% and 21% respectively, and the wear rate of the contact tip aperture for the coated copper alloy welding wire / coated ferroalloy welding wire does not exceed 11%.

[0084] When forming a copper alloy cladding layer using the coated copper alloy welding wire, control the parameters as follows:

[0085] The average arc voltage of cold - arc cladding is 20 V, the output pulse current is 60 A, the output pulse time is 50 ms, the wire feeding speed is 3 m / min, the cladding linear speed is 1 m / min, and the shielding gas is argon with a flow rate of 10 L / min; no pre - heating before welding, and natural air cooling after welding.

[0086] When forming a ferroalloy cladding layer using the coated ferroalloy welding wire, control the parameters as follows:

[0087] The average arc voltage of cold - arc cladding is 20 V, the output pulse current is 80 A, the output pulse time is 50 ms, the wire feeding speed is 5.0 m / min, the cladding linear speed is 2.5 m / min, and the shielding gas is argon with a flow rate of 10 L / min; no pre - heating before welding, and natural air cooling after welding.

[0088] The coated copper alloy welding wire / coated ferroalloy welding wire is subjected to cold - arc cladding on the cylinder block 17 (main body material: 30CrMnSi). The bonding strength is greater than 320 MPa. The average surface hardness of the copper alloy cladding layer is about 507 HV, and the average surface hardness of the ferroalloy cladding layer is about 614 HV. The inner wall and outer circle cladding layers of the column cylinder block 17 are resistant to neutral salt spray (NSS) corrosion for more than 1000 h and copper - accelerated acetic acid (CASS) corrosion for more than 480 h.

[0089] The copper alloy cladding layer, iron alloy cladding layer and nickel-chromium alloy cladding layer of the present invention are all dense and uniform in structure, without defects such as shrinkage cavities, cracks, and peeling. Under the condition of not using a sealing agent, the porosity is <0.1%, and the dilution rate is <5%. They are all metallurgically bonded to the substrate. After the cladding layer is prepared, NDT inspection (PT or MT) is carried out in accordance with JB4730.4 or JB4730.5 or equivalent standards, and the inspection results meet the first-level qualification. The cladding process is green and environmentally friendly, without dust and noise pollution. When used under the same downhole working conditions, the hydraulic cylinder of the present invention increases the strengthening layer (alloy cladding layer) on the surface of the component and combines with a good sealing structure, and its service life is increased by 3 to 4 times, which can ensure that it does not need to be overhauled uphole within 4.5 to 5 years under normal use conditions.

[0090] The above embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it cannot be understood as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

[0091] It should be understood that the orientation or positional relationship indicated by the above terms such as "center", "longitudinal", "transverse", "upper", "lower", "left", "right", "bottom", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. In the description of the present invention, unless otherwise specified, the meaning of "several" is more than two. In addition, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0092] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A hydraulic cylinder based on additive strengthening, comprising a cylinder block and a piston rod reciprocating along the cylinder block. Taking the direction in which the piston rod extends as the front, a guide sleeve and a pressure plate assembly are fixedly installed at the front end of the cylinder block. The front end of the piston rod passes through the guide sleeve and extends out of the pressure plate assembly, and a piston is sleeved at the rear end of the piston rod. It is characterized in that: The cylinder block includes a cylinder barrel and a cylinder bottom. The cylinder bottom includes a bottom plate connected to the rear end of the cylinder barrel. Ear plates extend backward from both the upper and lower ends of the bottom plate. Mounting holes penetrating vertically are provided on the ear plates, and wear-resistant sleeves are fixed in the mounting holes. Anti-loosening blocks symmetrically arranged up and down are embedded at the rear end of the piston rod and the piston. The anti-loosening blocks are tightly connected to the piston and are abutted against the rear end of the piston rod. A retaining ring and a sealing ring are installed at the joint between the front part of the piston and the piston rod. A piston seal extending in the circumferential direction and several piston guide rings are embedded on the outer edge of the piston. A static seal is provided between the outer edge of the guide sleeve and the inner wall of the cylinder barrel. Several piston rod guide rings are installed between the inner wall of the guide sleeve and the piston rod. A Step seal, a rod seal and a dust seal are sequentially arranged between the inner wall of the guide sleeve and the piston rod from the rear to the front. Among them, a copper alloy cladding layer for improving surface wear resistance and corrosion resistance is provided on the sliding surface of the inner wall of the cylinder barrel. Ferroalloy cladding layers for increasing surface hardness are provided at the joint between the inner wall of the cylinder barrel and the guide sleeve, on the outer side wall of the cylinder barrel and on the outer side wall of the cylinder bottom. A nickel-chromium alloy cladding layer is provided on the outer surface of the piston rod. Copper-plated passivation layers are provided on the outer surfaces of the piston and the guide sleeve. Several second fasteners are evenly spaced and installed on the guide sleeve in the circumferential direction. The axial center line of the second fasteners is parallel to the axial center line of the cylinder barrel. The rear end of the second fasteners is tightly connected to the front end of the cylinder barrel. The guide sleeve is tightly installed at the front end of the cylinder barrel through the second fasteners. The rear part of the guide sleeve is inserted into the front port of the cylinder barrel. The inner diameter of the cylinder barrel at the installation position of the guide sleeve is larger than the inner diameter of the sliding surface of the inner wall of the cylinder barrel. A valve block is provided at the rear end of the cylinder barrel. A hydraulic oil port is provided on the valve block. A hydraulic oil flow passage is provided in the cylinder barrel. The hydraulic oil flow passage is communicated with the hydraulic oil port. The reciprocating movement of the piston rod and the piston is realized by controlling the hydraulic oil in the cylinder barrel.

2. The hydraulic cylinder based on additive strengthening according to claim 1, wherein: The piston rod includes a threaded rod part, a smooth rod part and an earring part connected in sequence from the rear to the front. The diameter of the threaded rod part is smaller than that of the smooth rod part. A tapered surface is used for transition between the threaded rod part and the smooth rod part. A threaded hole part and a through hole part are coaxially provided in the piston. The threaded hole part is adaptively connected to the threaded rod part. The through hole part is adaptively connected to the smooth rod part. Grooves for embedding anti-loosening blocks are provided at the threaded rod part and the threaded hole part. A first fastener is installed on the anti-loosening block. The anti-loosening block is tightly installed on the piston through the first fastener. The axial center line of the first fastener is parallel to the axial center line of the piston rod. An annular groove is provided in the middle of the through hole part in the circumferential direction. The retaining ring and the sealing ring are embedded in the annular groove.

3. The hydraulic cylinder based on additive strengthening according to claim 1, wherein: The cylinder body is internally provided with a stroke sensor. The stroke sensor includes a sensor rod. A cavity for accommodating the sensor rod is axially provided at the center of the piston rod. The sensor rod passes through the sensor gland and extends into the cavity. A magnetic ring is embedded at the rear end of the cavity, and the magnetic ring is sleeved on the sensor rod. The sensor gland is embedded at the center of the front side of the bottom plate. The sensor gland is inserted and connected with the sensor rod. A positioning shoulder is arranged at the rear end of the sensor rod, and the rear end of the sensor gland abuts against the positioning shoulder. A connecting wire is arranged at the rear end of the sensor rod. The connecting wire is located inside the bottom plate and extends to the outer side of the bottom plate in a direction perpendicular to the sensor rod. An aviation plug bracket for inserting the end of the connecting wire is arranged on the outer side of the bottom plate. A through channel is arranged inside the aviation plug bracket. A cover plate for blocking the port is arranged at one port of the channel. A positioning sleeve is installed at the other port of the channel. A part of the positioning sleeve is inserted into the channel, and the other part of the positioning sleeve is inserted into the bottom plate. The connecting wire is inserted and connected with the positioning sleeve.

4. The hydraulic cylinder based on additive strengthening according to claim 1, wherein: The pressing plate assembly includes two semi-circular pressing plates arranged oppositely left and right. The semi-circular pressing plates are firmly installed on the front side of the guide sleeve. Steel pipes are welded on the front side of each semi-circular pressing plate, and the steel pipes on the left and right semi-circular pressing plates are arranged symmetrically left and right. The semi-circular pressing plates and the steel pipes are all made of 27SiMn material.

5. The hydraulic cylinder based on additive strengthening according to claim 1, wherein: The cylinder bottom and the cylinder barrel are both made of 30CrMnSi material. The wear-resistant sleeve is made of GCr15 material. The piston rod, the piston and the guide sleeve are all made of 42CrMo material. The anti-loosening block is made of 30CrMnSiA material.

6. The hydraulic cylinder based on additive strengthening according to claim 1, wherein: The copper alloy cladding layer is cladded by a copper alloy welding wire. The copper alloy welding wire includes the following components in mass percentage: Ni 4.5 - 6.0%, Al 7.0 - 9.0%, Fe 2.2 - 4.0%, Mn 1.0 - 2.0%, Ti 0.2 - 0.35%, Gd 0.02 - 0.05%, As 0.02 - 0.04%, C < 0.03%, and the balance is Cu. The ferroalloy cladding layer is cladded by a ferroalloy welding wire. The ferroalloy welding wire includes the following components in mass percentage: Ni 4.0 - 5.0%, Mo 2.0 - 3.0%, Cr 17.0 - 19.0%, Mn 0.35 - 0.75%, Si 0.35 - 0.4%, C ≤ 0.02%, P ≤ 0.02%, S ≤ 0.02%, and the balance is Fe.

7. The hydraulic cylinder based on additive strengthening according to claim 6, characterized in that: Both the surface of the copper alloy welding wire and the surface of the ferroalloy welding wire are coated with a nano composite coating. The nano composite coating is made of a coating liquid. The coating liquid includes the following components in mass percentage: intermetallic compound powder 5.4 - 7.2%, nano ceramic powder 1.8% - 3.6%, nano conductive carbon black 10 - 15%, nickel-based alloy powder 8 - 15%, titanate accelerator 1 - 3%, and the balance is the base liquid.

8. The hydraulic cylinder based on additive strengthening according to claim 1, wherein: The retaining ring adopts a retaining ring of type N0300-90, the sealing ring adopts an O-ring made of NBR90 material, the piston seal is made of a combined material of TPPE / NBR / POM, the piston guide ring and the piston rod guide ring are both made of POM material, the static seal, the rod seal and the dust ring are all made of PU material, and the Struthers seal is made of PTFE / NBR material.

9. The hydraulic cylinder based on additive strengthening according to any one of claims 1 to 8, characterized in that: The nickel-chromium alloy cladding layer is formed by cladding with nickel-chromium alloy welding wire; the thicknesses of the copper alloy cladding layer, the ferroalloy cladding layer and the nickel-chromium cladding layer are all 0.5 - 2.0 mm; the thickness of the copper-plated passivation layer is 0.03 - 0.05 mm.

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