Large-drift-diameter hydraulic bidirectional jar

Abstract

The large-drift-diameter hydraulic bidirectional jar comprises an inner pipe assembly, an outer pipe assembly, a time delay mechanism and a sealing assembly, and the inner diameter of the inner pipe assembly is not smaller than 57 mm so that an inner cutting knife can penetrate through the inner pipe assembly. According to the hydraulic two-way jar, the inner diameter of the hydraulic two-way jar is enough for an inner cutting knife to penetrate through so as to facilitate the cutting and fishing operation of a workover pipe column, meanwhile, the hydraulic two-way jar can improve the installation and maintenance convenience and the use reliability, and the tool cost can also be reduced.

Description

A large-diameter hydraulic bidirectional shock absorber Technical Field

[0001] This invention belongs to the field of shock device technology, specifically relating to a large-diameter hydraulic bidirectional shock device. Background Technology

[0002] Existing hydraulic shockers typically consist of an inner tube assembly, an outer tube assembly, a time-delay structure, and sealing components. Their operation is basically to lift or lower the inner tube assembly, allowing the hydraulic oil to be pressurized for a certain period of time to store energy, and finally release the stored energy instantaneously to generate shock force.

[0003] However, while existing hydraulic shockers can achieve the unlocking shock function, the following problems exist in actual use: 1. Most delay structures use Leeb valves, which are complex in structure and have high tool costs; 2. Most delay structures use independent pressure chambers and stroke areas, resulting in complex internal tool structures, high installation and maintenance precision requirements, and inconvenience in field application; 3. Rubber sealing components are prone to sealing failure under harsh downhole conditions, affecting the performance of the hydraulic shocker; 4. The inner diameter of the inner tube assembly is small, and when cutting and retrieving the workover string, the inner cutter cannot pass through the hydraulic shocker to enter the string, resulting in long retrieval cycles and high operating costs. Summary of the Invention

[0004] In order to solve all or some of the above problems, the purpose of this invention is to provide a large-diameter hydraulic bidirectional shock absorber that can improve the convenience of installation and maintenance and the reliability of use, reduce tool costs, and can also pass through the internal cutting blade to facilitate well workover string cutting and retrieval operations.

[0005] The present invention provides a large-diameter hydraulic bidirectional shock absorber, including an inner tube assembly, an outer tube assembly, a delay mechanism, and a sealing assembly. The inner diameter of the inner tube assembly is not less than 57 mm, so that the inner cutter can pass through the inner tube assembly.

[0006] Optionally, the inner tube assembly includes a splined inner cylinder, a coupling, an upper driving inner cylinder, a lower driving inner cylinder, and a locking inner cylinder connected sequentially from top to bottom. The outer tube assembly includes a splined outer cylinder, an upper connecting cylinder, an upper balancing cylinder, a middle connecting cylinder, a driving outer cylinder, a lower connecting cylinder, a lower balancing cylinder, a locking outer cylinder, and a connector connected sequentially from top to bottom. The splined inner cylinder cooperates with the splined outer cylinder and is used to restrict the relative rotation of the inner tube assembly and the outer tube assembly.

[0007] Optionally, the delay mechanism includes: two delay needle valves, one of which is disposed on the upper drive inner cylinder and the other on the lower drive inner cylinder, and the two delay needle valves are respectively in a sealing sliding fit with the drive outer cylinder; and three delay ring grooves, which are respectively disposed on the inner wall of the drive outer cylinder; wherein the three delay ring grooves and the two delay needle valves are arranged at intervals, and the three delay ring grooves are respectively filled with hydraulic oil, and the two delay needle valves are respectively used to squeeze the hydraulic oil in the corresponding delay ring groove to store pressure and energy, and when the two delay needle valves enter the corresponding delay ring grooves, the inner tube assembly can release the stored energy to generate a shock force.

[0008] Optionally, an upper balance ring cavity is provided between the upper drive inner cylinder and the upper balance cylinder, and an upper balance piston is provided on the upper drive inner cylinder located in the upper balance ring cavity. The upper balance piston is in a sealed sliding fit with the upper balance cylinder, and an upper balance hole communicating with the upper balance ring cavity is provided at the lower end of the upper balance cylinder.

[0009] Optionally, a lower balance ring cavity is provided between the lower drive inner cylinder and the lower balance cylinder, and a lower balance piston is provided on the lower drive inner cylinder located in the lower balance ring cavity. The lower balance piston is in a sealed sliding fit with the lower balance cylinder, and a lower balance hole communicating with the lower balance ring cavity is provided at the upper end of the lower balance cylinder.

[0010] Optionally, a locking member is provided between the locking inner cylinder and the locking outer cylinder. The locking member is used to prevent the locking inner cylinder from moving vertically, and the locking member can be unlocked under the action of external force, thereby releasing the restriction on the locking inner cylinder.

[0011] Optionally, the locking component includes: multiple locking bars spaced evenly around the inner locking cylinder, each locking bar having a pair of locking blocks; multiple pairs of locking slots on the inner locking cylinder, each pair of locking blocks capable of engaging into a corresponding locking slot; multiple upper limit blocks positioned above the corresponding locking bars; multiple lower limit blocks positioned below the corresponding locking bars; and a reset disc spring positioned between the inner locking cylinder and the outer locking cylinder. Each locking bar rests against the corresponding upper and lower limit blocks, the tops of the upper limit blocks abut against the lower balance cylinder for limitation, the lower limit blocks are capable of sliding vertically, and the reset disc spring pushes the lower limit blocks to synchronously reset upwards.

[0012] Optionally, the sealing assembly is disposed between the upper driving inner cylinder and the middle connecting cylinder, between the lower driving inner cylinder and the lower connecting cylinder, and between the locking inner cylinder and the connector.

[0013] Optionally, each of the sealing components includes a dustproof ring and two sealing ring assemblies. Each sealing ring assembly includes a D-shaped sealing ring, two limiting retaining rings, and two triangular retaining rings. The D-shaped sealing ring and the triangular retaining rings are made of rubber, and the limiting retaining rings are made of metal. The two limiting retaining rings and the two triangular retaining rings in each sealing ring assembly are symmetrically distributed on both sides of the corresponding D-shaped sealing ring, and each limiting retaining ring is located between the D-shaped sealing ring and the corresponding triangular retaining ring.

[0014] Optionally, a mud scraper assembly is provided at the upper end of the spline outer cylinder, and the mud scraper assembly is used to scrape off the mud on the spline inner cylinder.

[0015] As can be seen from the above technical solution, the large-diameter hydraulic bidirectional shock absorber provided by the present invention has the following advantages: the hydraulic bidirectional shock absorber can improve the convenience of installation and maintenance and the reliability of use, reduce tool costs, and can also pass through the internal cutting blade to facilitate well workover string cutting and retrieval operations.

[0016] Other features and advantages of the present invention will be set forth in the following description. Attached Figure Description

[0017] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the technical solutions of the present invention, and do not constitute a limitation on the technical solutions of the present invention.

[0018] Figure 1 is a cross-sectional view of an embodiment of the present invention; Figure 2 is a cross-sectional view of the inner tube assembly in an embodiment of the present invention; Figure 3 is a cross-sectional view of the outer tube assembly in an embodiment of the present invention; Figure 4 is a cross-sectional view of an embodiment of the present invention, mainly showing the delay mechanism; Figure 5 is a cross-sectional view of an embodiment of the present invention, mainly showing components such as the upper balance piston; Figure 6 is a cross-sectional view of an embodiment of the present invention, mainly showing components such as the lower balance piston; Figure 7 is a cross-sectional view of an embodiment of the present invention, mainly showing the locking component; Figure 8 is an enlarged schematic diagram of area A in Figure 7; Figure 9 is an enlarged schematic diagram of area B in Figure 1; Figure 10 is an enlarged schematic diagram of area C in Figure 1.

[0019] Explanation of reference numerals in the attached drawings: 1. Inner tube assembly; 101. Splined inner cylinder; 102. Connecting joint; 103. Upper drive inner cylinder; 104. Lower drive inner cylinder; 105. Locking inner cylinder; 2. Outer tube assembly; 201. Splined outer cylinder; 202. Upper connecting cylinder; 203. Upper balance cylinder; 204. Middle connecting cylinder; 205. Drive outer cylinder; 206. Lower connecting cylinder; 207. Lower balance cylinder; 208. Locking outer cylinder; 209. Connector; 3. Delay mechanism; 31. Delay needle valve; 32. Delay ring 4. Groove; 41. Sealing assembly; 42. Dustproof ring; 43. Sealing ring assembly; 44.21. D-shaped sealing ring; 45. Limiting ring; 46.23. Triangular retaining ring; 5. Upper balance ring cavity; 6. Upper balance piston; 7. Upper balance hole; 8. Lower balance ring cavity; 9. Lower balance piston; 10. Lower balance hole; 11. Locking element; 111. Locking strip; 112. Locking block; 113. Locking groove; 114. Upper limit block; 115. Lower limit block; 116. Reset disc spring; 12. Scraper ring assembly. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be arbitrarily combined with each other.

[0021] Figures 1-10 illustrate an embodiment of the present invention, disclosing a large-diameter hydraulic bidirectional shock absorber, comprising an inner tube assembly 1, an outer tube assembly 2, a delay mechanism 3, and a sealing assembly 4. The inner diameter of the inner tube assembly 1 is not less than 57 mm, allowing the internal cutting tool to pass through it for convenient well workover string cutting and retrieval operations. In this embodiment, the inner diameter of the inner tube assembly 1 is 60 mm, sufficient for on-site internal cutting tool insertion.

[0022] In one embodiment, as shown in Figures 1, 2, and 3, the inner tube assembly 1 includes a splined inner cylinder 101, a mating joint 102, an upper driving inner cylinder 103, a lower driving inner cylinder 104, and a locking inner cylinder 105, which are threaded together from top to bottom. The outer tube assembly 2 includes a splined outer cylinder 201, an upper connecting cylinder 202, an upper balancing cylinder 203, a middle connecting cylinder 204, a driving outer cylinder 205, a lower connecting cylinder 206, a lower balancing cylinder 207, a locking outer cylinder 208, and a connector 209, which are threaded together from top to bottom. The splined inner cylinder 101 cooperates with the splined outer cylinder 201 and is used to restrict the relative rotation of the inner tube assembly 1 and the outer tube assembly 2, that is, to prevent the relative rotation of the inner tube assembly 1 and the outer tube assembly 2.

[0023] In one embodiment, as shown in Figures 1 and 4, the delay mechanism 3 includes two delay needle valves 31 and three delay ring grooves 32. One delay needle valve 31 is fixed on the upper drive inner cylinder 103, and the other delay needle valve 31 is disposed on the lower drive inner cylinder 104. The two delay needle valves 31 are respectively in a sealing sliding fit with the drive outer cylinder 205.

[0024] In one embodiment, as shown in Figure 4, three delay annular grooves 32 are respectively disposed on the inner wall of the drive outer cylinder 205. The three delay annular grooves 32 and two delay needle valves 31 are arranged at intervals, and the three delay annular grooves 32 are respectively filled with hydraulic oil. The two delay needle valves 31 are used to squeeze the hydraulic oil in the corresponding delay annular grooves 32 to store pressure and energy. When the two delay needle valves 31 enter the corresponding delay annular grooves 32, the inner tube assembly 1 can release the stored energy to generate a shock force.

[0025] In this embodiment, the internal flow channel of the delay valve 31 can achieve high-precision flow control, maintaining a stable flow rate even when adjusting to a small flow rate, thus ensuring a stable and reliable delay. Furthermore, the delay valve 31 has a relatively simple structure and lower cost. In addition, a filter screen is added to the front end of the delay valve 31 to prevent clogging, and a plug is installed on the filter screen side to prevent the delay valve 31 from moving.

[0026] The hydraulic bidirectional vibrator in this embodiment adopts a single-chamber, single-stroke design. When the vibrator performs bidirectional vibration operations, the pressure-bearing stroke during its up-and-down movement is within the same interval and passes through the same interference fit area. This structure satisfies the functional requirements and is convenient to install and maintain. Furthermore, the hydraulic bidirectional vibrator offers higher reliability and reduces tooling costs.

[0027] In one embodiment, as shown in Figures 1 and 5, an upper balance ring cavity 5 is provided between the upper drive inner cylinder 103 and the upper balance cylinder 203. An upper balance piston 6 is provided on the upper drive inner cylinder 103 and located in the upper balance ring cavity 5. The upper balance piston 6 is in a sealed sliding fit with the upper balance cylinder 203, and an upper balance hole 7 communicating with the upper balance ring cavity 5 is provided at the lower end of the upper balance cylinder 203 to dynamically balance the internal and external pressure difference of the hydraulic bidirectional shock absorber.

[0028] In one embodiment, as shown in Figures 1 and 6, a lower balance ring cavity 8 is provided between the lower drive inner cylinder 104 and the lower balance cylinder 207. A lower balance piston 9 is provided on the lower drive inner cylinder 104 and located in the lower balance ring cavity 8. The lower balance piston 9 is in a sealed sliding fit with the lower balance cylinder 207, and a lower balance hole 10 communicating with the lower balance ring cavity 8 is provided at the upper end of the lower balance cylinder 207 to dynamically balance the internal and external pressure difference of the hydraulic bidirectional shock absorber.

[0029] In one embodiment, as shown in Figures 1 and 7, a locking member 11 is provided between the locking inner cylinder 105 and the locking outer cylinder 208. The locking member 11 is used to prevent the locking inner cylinder 105 from moving vertically, and the locking member 11 can be unlocked under the action of external force, thus releasing the restriction on the locking inner cylinder 105. Simply put, when the inner tube assembly 1 is not subjected to external force, the inner tube assembly 1 and the outer tube assembly 2 are in a locked state. If the inner tube assembly 1 is lifted or pressed down, the locking member 11 can be unlocked, so that the inner tube assembly 1 can move vertically.

[0030] In one embodiment, as shown in Figures 7 and 8, the locking member 11 includes a plurality of locking strips 111 spaced at equal intervals around the locking inner cylinder 105, and each locking strip 111 is integrally formed with a pair of locking blocks 112. The locking inner cylinder 105 is provided with a plurality of locking grooves 113, and each pair of locking blocks 112 can be engaged into the corresponding locking groove 113.

[0031] In one embodiment, as shown in Figures 7 and 8, each locking bar 111 has an upper limit block 114 above it and a lower limit block 115 below it, with each locking bar 111 abutting between its corresponding upper limit block 114 and lower limit block 115. Simultaneously, the tops of the multiple upper limit blocks 114 abut against the lower balance cylinder 207 for limitation, and the multiple lower limit blocks 115 are capable of sliding vertically.

[0032] In one embodiment, as shown in Figures 7 and 8, a reset disc spring 116 is provided between the locking inner cylinder 105 and the locking outer cylinder 208. The top of the reset disc spring 116 abuts against multiple lower limit blocks 115 respectively, and the bottom abuts against the stepped groove of the inner wall of the locking outer cylinder 208 for limitation. At the same time, the reset disc spring 116 is used to push the multiple lower limit blocks 115 to reset synchronously upward.

[0033] In this embodiment, the upper limit block 114 and the lower limit block 115 are respectively provided with guide slopes on their sides that are close to each other, the two ends of the locking bar 111 are respectively provided with guide arc surfaces, the locking block 112 is connected to the locking bar 111 by an arc transition, and the locking groove 113 is connected to the outer wall of the locking outer cylinder 208 by an arc transition, so as to improve the guiding effect and enable the locking inner cylinder 105 and the locking outer cylinder 208 to successfully complete locking and unlocking.

[0034] In one embodiment, as shown in Figures 1 and 9, the sealing assembly 4 is disposed between the upper driving inner cylinder 103 and the middle connecting cylinder 204, between the lower driving inner cylinder 104 and the lower connecting cylinder 206, and between the locking inner cylinder 105 and the connector 209. Of course, the sealing assembly 4 can also be added between the upper balance piston 6 and the lower balance piston 9 to ensure a sealing effect.

[0035] In one embodiment, as shown in FIG9, each sealing component 4 includes a dustproof ring 41 and two sealing ring assemblies 42. Each sealing ring assembly 42 includes a D-shaped sealing ring 421, two limiting rings 422 and two triangular rings 423. The D-shaped sealing ring 421 and the triangular rings 423 are made of rubber material, and the limiting rings 422 are made of metal material.

[0036] In one embodiment, as shown in FIG9, the two limiting retaining rings 422 and the two triangular retaining rings 423 in each sealing ring assembly 42 are symmetrically distributed on both sides of the corresponding D-shaped sealing ring 421, and each limiting retaining ring 422 is located between the D-shaped sealing ring 421 and the corresponding triangular retaining ring 423.

[0037] When the sealing ring assembly 42 wears, the limiting retaining ring 422 wears first, followed by the triangular retaining ring 423 and the D-type sealing ring. The sealing ring has a small contact area, and its rectangular cross-section provides stronger shear resistance, making it more wear-resistant than conventional rubber sealing rings. Furthermore, the independently designed sealing ring assembly 42 facilitates maintenance and replacement, improving assembly efficiency.

[0038] In one embodiment, as shown in Figures 1 and 10, a mud scraper assembly 12 is provided at the upper end of the splined outer cylinder 201. When the inner tube assembly 1 moves vertically, the mud scraper assembly 12 can scrape off the mud on the splined inner cylinder 101 to prevent the mud from entering between the inner tube assembly 1 and the outer tube assembly 2.

[0039] The hydraulic bidirectional shock absorber in this embodiment operates as follows: When the hydraulic bidirectional shock absorber strikes downwards, it pushes the splined inner cylinder 101, causing the remaining components of the inner tube assembly 1 to move downwards synchronously. At this time, the lower limit block 115 moves downwards under the action of the locking bar 111, and the locking block 112 disengages from the locking groove 113, thereby unlocking the inner tube assembly 1 and the outer tube assembly 2. As the inner tube assembly 1 continues to move downwards, the two delay needle valves 31 respectively squeeze the hydraulic oil in the delay ring groove 32 located below them. Since the hydraulic oil cannot pass through the outer surface of the delay needle valve 31, it can only pass through the flow channel inside the delay needle valve 31. Because the flow rate of the delay needle valve 31 is very small, the hydraulic oil is compressed in the delay ring groove 32 to form a high-pressure area.

[0040] As the inner tube assembly 1 continues to move downwards, when the two delay needle valves 31 are fully inserted into the delay ring grooves 32 located below them, the pressure-holding stroke ends, and the hydraulic oil in the high-pressure zone can pass through the outer surface of the delay needle valves 31 to release the stored pressure energy instantly, thereby achieving the downward impact operation. Subsequently, when the upper spline inner cylinder 101 returns to its initial state, the locking block 112 aligns with the corresponding locking groove 113. At this time, the lower limit block 115 moves upwards and resets under the action of the reset disc spring 116, and the locking bar 111 moves toward the locking inner cylinder 105 under the combined action of the upper limit block 114 and the lower limit block 115. When the locking block 112 engages in the locking groove 113, the inner tube assembly 1 and the outer tube assembly 2 are locked.

[0041] When the hydraulic bidirectional vibrator strikes upwards, the upward-lifting splined inner cylinder 101 drives the remaining components of the inner tube assembly 1 to move upwards synchronously. Similar to the downward-firing operation, the locking element 11 unlocks first, and then the two delay needle valves 31 respectively squeeze the hydraulic oil in the delay ring grooves 32 above them to store pressure and energy. As the inner tube assembly 1 continues to move upwards, when the pressure-storing stroke of the two delay needle valves 31 ends, the hydraulic oil in the high-pressure zone can pass through the outer surface of the delay needle valves 31, so that the stored pressure energy is released instantaneously, thereby realizing the upward-firing operation. Subsequently, when the splined inner cylinder 101 is lowered to the initial state, the locking block 112 engages in the locking groove 113, thereby locking the inner tube assembly 1 and the outer tube assembly 2.

[0042] As can be seen from the above, the hydraulic bidirectional shock absorber has the following advantages: precise and reliable flow control; the delay needle valve 31, combined with the filter screen design, ensures the reliability of the delay structure function while reducing tool costs; the single-cavity single-stroke design simplifies the bidirectional shock structure, improves tool installation and maintenance efficiency, and reduces tool usage costs; the sealing component 4 has an independent multi-wear-resistant structure design, where the more wear-resistant metal limiting ring 422 is worn first, and then the rubber sealing rings on both sides are worn. The selection of triangular retaining rings 423 and D-type sealing rings with better wear resistance on both sides further improves the performance of the sealing component 4, and the independent design facilitates on-site tool maintenance and replacement; the large-diameter inner diameter design allows the internal cutting tool to directly penetrate the inner diameter of the shock absorber and be lowered into the tubing string during well workover operations, reducing the tubing string retrieval cycle and lowering on-site operation costs.

[0043] It should be noted that, unless otherwise stated, the technical or scientific terms used in this invention should have the ordinary meaning as understood by one of ordinary skill in the art.

[0044] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly defined.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A large-diameter hydraulic bidirectional shock absorber, comprising an inner tube assembly (1), an outer tube assembly (2), a delay mechanism (3), and a sealing assembly (4), characterized in that, The inner diameter of the inner tube assembly (1) is not less than 57 mm, so that the inner cutter can pass through the inner tube assembly (1).

2. The hydraulic bidirectional shock absorber according to claim 1, characterized in that, The inner tube assembly (1) includes a splined inner tube (101), a connecting joint (102), an upper driving inner tube (103), a lower driving inner tube (104), and a locking inner tube (105) connected from top to bottom. The outer tube assembly (2) includes a splined outer tube (201), an upper connecting tube (202), an upper balancing tube (203), a middle connecting tube (204), a driving outer tube (205), a lower connecting tube (206), a lower balancing tube (207), a locking outer tube (208), and a connector (209) connected from top to bottom. The splined inner tube (101) cooperates with the splined outer tube (201) and is used to restrict the relative rotation of the inner tube assembly (1) and the outer tube assembly (2).

3. The hydraulic bidirectional shock absorber according to claim 2, characterized in that, The delay mechanism (3) includes: two delay needle valves (31), one of which is located on the upper drive inner cylinder (103) and the other is located on the lower drive inner cylinder (104), and the two delay needle valves (31) are respectively in a sealing sliding fit with the drive outer cylinder (205); and three delay annular grooves (32), which are respectively located in the inner part of the drive outer cylinder (205). On the wall; wherein, three delay ring grooves (32) and two delay needle valves (31) are arranged at intervals, and the three delay ring grooves (32) are filled with hydraulic oil respectively, and the two delay needle valves (31) are respectively used to squeeze the hydraulic oil in the corresponding delay ring grooves (32) to store energy, and when the two delay needle valves (31) enter the corresponding delay ring grooves (32) respectively, the inner tube assembly (1) can release the stored energy to generate shock force.

4. The hydraulic bidirectional shock absorber according to claim 2, characterized in that, An upper balance ring cavity (5) is provided between the upper drive inner cylinder (103) and the upper balance cylinder (203). An upper balance piston (6) is provided on the upper drive inner cylinder (103) and located in the upper balance ring cavity (5). The upper balance piston (6) is in a sealed sliding fit with the upper balance cylinder (203), and an upper balance hole (7) communicating with the upper balance ring cavity (5) is provided at the lower end of the upper balance cylinder (203).

5. The hydraulic bidirectional shock absorber according to claim 2, characterized in that, A lower balance ring cavity (8) is provided between the lower drive inner cylinder (104) and the lower balance cylinder (207). A lower balance piston (9) is provided on the lower drive inner cylinder (104) and located in the lower balance ring cavity (8). The lower balance piston (9) is in a sealed sliding fit with the lower balance cylinder (207), and a lower balance hole (10) communicating with the lower balance ring cavity (8) is provided at the upper end of the lower balance cylinder (207).

6. The hydraulic bidirectional shock absorber according to claim 2, characterized in that, A locking member (11) is provided between the locking inner cylinder (105) and the locking outer cylinder (208). The locking member (11) is used to prevent the locking inner cylinder (105) from moving vertically, and the locking member (11) can be unlocked under the action of external force and release the restriction on the locking inner cylinder (105).

7. The hydraulic bidirectional shock absorber according to claim 6, characterized in that, The locking element (11) includes: multiple locking bars (111) spaced evenly around the locking inner cylinder (105), each locking bar (111) having a pair of locking blocks (112); multiple locking slots (113) spaced on the locking inner cylinder (105), each pair of locking blocks (112) capable of engaging into a corresponding locking slot (113); multiple upper limit blocks (114) spaced above the corresponding locking bars (111); and multiple lower limit blocks (115) spaced separately. The locking bar (111) is positioned below the corresponding locking bar (111); a reset disc spring (116) is positioned between the locking inner cylinder (105) and the locking outer cylinder (208); wherein each locking bar (111) abuts against the corresponding upper limit block (114) and lower limit block (115), the tops of the multiple upper limit blocks (114) abut against the lower balance cylinder (207) respectively, the multiple lower limit blocks (115) can slide vertically, and the reset disc spring (116) is used to push the multiple lower limit blocks (115) to reset synchronously upward.

8. The hydraulic bidirectional shock absorber according to claim 2, characterized in that, The sealing assembly (4) is disposed between the upper driving inner cylinder (103) and the middle connecting cylinder (204), between the lower driving inner cylinder (104) and the lower connecting cylinder (206), and between the locking inner cylinder (105) and the connector (209).

9. The hydraulic bidirectional shock absorber according to claim 8, characterized in that, Each sealing assembly (4) includes a dustproof ring (41) and two sealing ring assemblies (42). Each sealing ring assembly (42) includes a D-shaped sealing ring (421), two limiting retaining rings (422), and two triangular retaining rings (423). The D-shaped sealing ring (421) and the triangular retaining rings (423) are made of rubber, and the limiting retaining rings (422) are made of metal. The two limiting retaining rings (422) and the two triangular retaining rings (423) in each sealing ring assembly (42) are symmetrically distributed on both sides of the corresponding D-shaped sealing ring (421), and each limiting retaining ring (422) is located between the D-shaped sealing ring (421) and the corresponding triangular retaining ring (423).

10. The hydraulic bidirectional shock absorber according to claim 2, characterized in that, The upper end of the spline outer cylinder (201) is provided with a mud scraper assembly (12), and the mud scraper assembly (12) is used to scrape off the mud on the spline inner cylinder (101).

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