Long-service-life three-telescopic leg for hydraulic support and hydraulic support comprising same

Abstract

A long-service-life three-telescopic leg for a hydraulic support and a hydraulic support comprising same. A snap-fit portion (222) is provided on a pipe joint seat (22) of a liquid inlet pipe structural member (2), and by means of snap-fit connection between the snap-fit portion and a cylinder bottom groove (13), the damage to a base material of a cylinder tube caused by welding fatigue or during welding is avoided. A guide assembly (5) is provided between the outer side of an outermost intermediate cylinder (3) and the inner side of an outer cylinder (1); the guide assembly comprises a guide ring (51) arranged at the lower end of the outermost intermediate cylinder and a guide sleeve (52) arranged at the upper end of the outermost intermediate cylinder; and the guide ring and the guide sleeve are structurally improved to optimize the performance thereof under an eccentric load working condition. These improvement measures effectively improve the safety of hydraulic supports and prolong the service life thereof, providing significant advantages in coal mining.

Description

A high-life three-telescopic column for hydraulic support and hydraulic support thereof Technical Field

[0001] The present invention relates to the technical field of coal mine support equipment, in particular to a high-life three-telescopic column for a hydraulic support and a hydraulic support thereof. Background Art

[0002] In the process of underground coal mine production, safety is a red line that can never be crossed. In the process of tunneling underground in coal mines, support equipment is mainly used to support the top of the tunnel. At present, the most important support equipment is the hydraulic support. The hydraulic support mainly includes a base, a connecting rod mechanism, a shield beam, a top beam and a column. Among them, the rear end of the base is hinged to one end of the shield beam through a connecting rod mechanism, and the other end of the shield beam is hinged to the top beam. The top beam and the base are arranged parallel to each other, and a column is set between the base and the top beam. The top beam is contacted with the coal seam by the extension and contraction of the column, thereby supporting the tunnel and ensuring the safety of the workers under the hydraulic support.

[0003] As a major coal producer, China boasts a vast territory, abundant coal resources, and diverse coal seam distribution. Therefore, due to varying geological structures, coal seams of varying thickness exist during coal mining. Seams less than 1.3 meters thick are considered thin seams, those between 1.3 and 3.8 meters thick are medium-thick seams, and those greater than 3.8 meters thick are thick seams. When mining each seam, hydraulic supports appropriate to its thickness are required. However, within the same area, coal seam thickness can vary significantly along the direction of excavation. For example, within the same working face, the thickness of the coal seam can range from 2 meters to 4.8 meters along the direction of excavation.

[0004] At present, the columns used in hydraulic supports include single telescopic columns, mechanically extended double telescopic columns, and hydraulic double telescopic columns. Due to the telescopic ratio limitations of the lifting range of traditional hydraulic supports, in previous mining, for such situations where the thickness of the coal seam varies greatly, only hydraulic supports corresponding to the changes in the thickness of the coal seam can be used for layered and segmented mining. This requires the purchase of two or more sets of equipment to achieve this. Specifically, coal seams with similar heights on the working face are segmented, and due to the selection of columns, local mining is carried out using comprehensive mining equipment that is compatible with them. This results in the need to frequently replace different models of hydraulic supports as comprehensive mining equipment when mining on the same working face, resulting in a huge waste of coal mining. Therefore, in recent years, a hydraulic support with three telescopic columns has become available on the market, which realizes the use of three telescopic columns on the hydraulic support, breaking through the limitations of the telescopic ratio of traditional telescopic columns and realizing that one set of hydraulic supports can be used in "thin-medium-thick" coal seams.

[0005] The use of an existing hydraulic support with three telescopic columns can greatly improve the telescopic ratio of the hydraulic support to adapt to the support capacity of different coal seams. However, the existing three telescopic columns include an outer cylinder, a middle cylinder, and a piston. A liquid inlet pipe structure is directly welded to the outside of the outer cylinder. The liquid inlet pipe structure passes through the outer cylinder of the telescopic column and is connected to the inner cavity of the outer cylinder, thereby allowing hydraulic oil to enter the cylinder to achieve the hydraulic oil pushing the remaining middle cylinders and pistons at each level. However, the existing liquid inlet pipe structure is generally arranged along the longitudinal direction of the cylinder tube, and the outer wall of the liquid inlet pipe structure is welded to the outer wall of the cylinder tube, which causes damage to the cylinder tube during welding. In addition, the liquid outlet end of the liquid inlet pipe is connected to the inner cavity of the cylinder tube body structure through a pipe joint seat structure, and the pipe joint seat structure is welded to the cylinder bottom structure of the bottom cover. If the column is used for a long time, the welding between the pipe joint seat structure and the cylinder bottom structure will become unstable or fatigued, resulting in failure of the weld at this location, causing hydraulic oil leakage, and thus reducing the service life of the three telescopic columns. Summary of the Invention

[0006] (1) Technical issues to be resolved

[0007] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a three-telescopic column with a long service life for a hydraulic support, which solves the technical problem of the short service life of the three-telescopic column.

[0008] (2) Technical solution

[0009] In order to achieve the above objectives, the main technical solutions adopted by the present invention include:

[0010] The cam is connected to the outer wall of the hydraulic support by a plurality of cylinders, and the cylinder is connected to the bottom of the cylinder by a plurality of cylinders. The cam is connected to the outer wall of the hydraulic support by a plurality of cylinders. The cam is connected to the bottom of the cylinder by a plurality of cylinders. The parts cooperate with each other and are inclined at a certain angle relative to the axial direction of the cylinder tube body; a guide assembly is provided between the outer side of the outermost middle cylinder and the inner side of the outer cylinder, and the guide assembly includes a guide ring arranged at the lower end of the outermost middle cylinder; the guide ring includes a first guide ring monomer, a second guide ring monomer and a third guide ring monomer which are arranged in sequence along the axial direction of the middle cylinder, and the first guide ring monomer, the second guide ring monomer and the third guide ring monomer are all arranged in the guide groove of the outer wall of the middle cylinder, and the width in the axial direction of the middle cylinder is as follows: the first guide ring monomer>the second guide ring monomer>the third guide ring monomer; the guide assembly also includes a guide sleeve arranged at the upper end of the outermost middle cylinder; the guide sleeve includes a first guide sleeve, a guide sleeve seal and a second guide sleeve which are arranged in sequence along the axial direction of the middle cylinder, and the interior of the second guide sleeve is provided with an oil filling hole connected to the outside.

[0011] Preferably, the clamping part includes a cylinder body, which is provided with a first-level step end face and a second-level step end face in the axial direction of the cylinder body, so that the cylinder body forms a first axial cylinder wall and a second axial cylinder wall with successively decreasing diameters, and a first sealing groove, a second sealing groove and a pipe joint seat clamping groove are provided along the axial direction of the second axial cylinder wall; the first sealing groove and the second sealing groove are both provided with sealing rings to seal the gap between the pipe joint seat and the outer cylinder; a pipe joint seat clamping ring is formed between the second sealing groove and the pipe joint seat clamping groove and extends radially outward from the cylinder body; the cylinder bottom clamping groove includes a cylinder bottom interface sealing section connected to the inner cavity of the cylinder tube body, a clamping groove axially provided along the interface sealing section, a cylinder bottom clamping platform and an external interface; the clamping groove is clamped with the pipe joint seat clamping ring; the cylinder bottom clamping platform is clamped in cooperation with the pipe joint seat clamping groove.

[0012] Preferably, the pipe joint seat clamping ring is two fan-shaped clamping rings, and one end surface of the two clamping rings close to the connecting portion is an inclined conical surface.

[0013] Preferably, it also includes a protective cover assembly sleeved on the liquid inlet pipe body, one end of the protective cover assembly is inserted into the fixing hole of the outer cylinder, and the other end of the protective cover assembly is detachably connected to the valve connecting plate.

[0014] Preferably, it includes a piston arranged in the middle cylinder; the piston includes a column tube that can slide axially relative to the innermost middle cylinder cavity and a column head for sealing the column tube, and the column head and the column tube are integrally formed.

[0015] Preferably, a stress groove structure with an arc chamfer transition is formed between the column head and the inner side wall of the column tube.

[0016] Preferably, the inclination angle ranges from 120° to 140°.

[0017] In a second aspect, the present invention further provides a hydraulic support comprising three telescopic columns with a long service life, a base, a top beam, a shield beam, a front connecting rod and a rear connecting rod for the hydraulic support.

[0018] (3) Beneficial effects

[0019] The beneficial effects of the present invention are as follows: a long-life three-telescopic column for a hydraulic support of the present invention is provided with a clamping portion on the pipe joint seat of the liquid inlet pipe structure, and the clamping portion cooperates with the clamping groove at the cylinder bottom to clamp the liquid inlet pipe structure to the cylinder bottom, and ensures that hydraulic oil enters the cylinder bottom through the liquid inlet pipe body and the pipe joint seat, and then enters the inner cavity of the outer cylinder to ensure the normal operation of the middle cylinder and the piston. Moreover, compared with the welding between the pipe joint seat structure and the cylinder bottom structure in the prior art, the connection with the cylinder bottom through the clamping groove structure reduces the number of welds in conventional positions, avoids hydraulic oil leakage in the column due to welding fatigue or damage to the cylinder tube base material during welding, and then avoids the occurrence of overall failure of the column, thereby greatly improving the reliability and service life of the three-telescopic column.

[0020] Correspondingly, the hydraulic support with columns has also undergone corresponding changes. In addition, the base, top beam, shield beam, front connecting rod and rear connecting rod are used to achieve stable support and improve the service life of the overall hydraulic support.

[0021] Furthermore, a guide assembly is installed between the outer side of the outermost middle cylinder and the inner side of the outer cylinder. This guide assembly comprises a guide ring at the lower end of the outermost middle cylinder and a guide sleeve at the upper end of the outermost middle cylinder. Improvements to the guide ring and sleeve structures have been made to optimize their performance in handling eccentric load conditions. These improvements have effectively increased the safety and service life of the hydraulic support, providing significant advantages in coal mining. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG1 is a schematic structural diagram of a hydraulic support with three telescopic columns according to the present invention in one state;

[0023] FIG2 is a schematic structural diagram of a hydraulic support with three telescopic columns according to the present invention in another state;

[0024] FIG3 is a schematic structural diagram of an existing three-telescopic column;

[0025] FIG4 is a schematic structural diagram of three telescopic columns of the present invention;

[0026] FIG5 is a schematic structural diagram of a liquid inlet pipe assembly of three telescopic columns of the present invention;

[0027] FIG6 is a schematic structural diagram of a pipe joint seat of a liquid inlet pipe assembly of three telescopic columns of the present invention;

[0028] FIG7 is a schematic diagram of the longitudinal cross-sectional structure of FIG6;

[0029] FIG8 is a schematic structural diagram of the cylinder bottom portion in FIG4 ;

[0030] FIG9 is a schematic structural diagram of the protective cover assembly in FIG4 ;

[0031] FIG10 is a schematic structural diagram of the connection between the protective cover assembly and the valve connecting plate in FIG4;

[0032] FIG11 is a schematic diagram of the cross-sectional structure of the active column head;

[0033] Figure 12 is a schematic structural diagram of the welding between the first-stage middle cylinder and the cylinder tube.

[0034] [Description of Figure Reference Numerals] 100′: existing three-telescopic column; 1′: cylinder bottom structure; 2′: pipe joint seat structure; 3′: first piston guide ring structure; 4′: second piston guide ring structure; 5′: liquid inlet pipe structure; 6′: protective cover structure; 7′: cylinder body structure; 8′: valve connecting plate; 9′: first-stage middle cylinder structure; 10′: second-stage middle cylinder structure; 11′: column tube structure; 12′: pressure balancing structure; 13′: first guide sleeve structure; 14′: guide sleeve sealing structure; 15′: second guide sleeve structure; 16′: static sealing structure; 17′: piston; 18′: column head structure; 100: Three telescopic columns; 1: Outer cylinder; 11: Cylinder bottom; 12: Cylinder tube body; 13: Cylinder bottom slot; 131: Cylinder bottom interface sealing section; 132: Cylinder bottom clamping platform; 133: External interface; 134: Fixing hole; 135: Snap-on slot; 2: Liquid inlet pipe structure; 21: Liquid inlet pipe body; 22: Pipe joint seat; 221: Connecting portion; 222: Snap-on portion; 2221: First axial cylinder wall; 2222: Second axial cylinder wall; 2223: First sealing groove; 2224: Second sealing groove; 2225: Pipe joint seat slot; 2226: Pipe joint seat snap ring; 23: Valve connection plate; 3: Middle cylinder; 3 1: First-stage middle cylinder; 32: Second-stage middle cylinder; 4: Live column; 41: Column tube; 42: Column head; 5: Guide assembly; 51: Guide ring; 511: First guide ring monomer; 512: Second guide ring monomer; 513: Third guide ring monomer; 52: Guide sleeve; 521: First guide sleeve; 522: Guide sleeve seal; 523: Second guide sleeve; 53: Oil filling hole; 54: Oil filling cylinder cover; 6: Protective cover assembly; 61: Fixed plug column; 62: L-shaped connecting frame; 7: Pressure balance bar; 8: Clamp; 9: Pad; 10: Circumferential weld; 101: Plug weld; 102: Welding plug; 103: Cylinder tube; 200: Base; 300: Top beam; 400: Protective beam; 500: Front connecting rod; 600: Rear connecting rod. DETAILED DESCRIPTION

[0035] To better explain the present invention and facilitate understanding, the following detailed description of the present invention is provided below, using specific embodiments in conjunction with the accompanying drawings. The directional terms "upper" and "lower" mentioned herein are referenced to the orientation shown in Figure 1 . The position of base 200 in Figure 1 is defined as "lower," while the position of top beam 300 is defined as "upper."

[0036] Since the three telescopic columns 100' are suitable for supporting different coal seams, the three telescopic columns 100' are used more frequently. Under this high frequency of use, the service life of the existing three telescopic columns is short. The main reasons for the short service life are as follows: First, the inner wall of the existing pipe joint seat structure 2' and the cylinder bottom structure 1' are welded, which often causes the welds of the three telescopic columns 100' to fail due to unstable welding quality or limitations of welding fatigue limits. Moreover, once the weld fails, the three telescopic columns 100' will be unable to work, and the entire hydraulic support will need to be transported from the coal mine to the ground before it can be re-welded or the three telescopic columns 100' can be replaced. This will also affect the efficiency of underground operations as a whole and waste time. Furthermore, the specifications of the first piston guide ring structure 3' and the second piston guide ring structure 4' of the existing three telescopic columns 100' are identical. Therefore, when the hydraulic support's top beam is subjected to an eccentric load during operation, the three telescopic columns 100' will also be subjected to the eccentric load, resulting in the first piston guide ring structure 3' experiencing significantly greater wear than the second piston guide ring structure 4', further reducing the service life of the three telescopic columns 100'. Furthermore, the specifications of the first guide sleeve structure 13' and the second guide sleeve structure 15' are identical. Since the first guide sleeve structure 13' is located inside the guide sleeve sealing structure 14', where it can be lubricated by the emulsion, the second guide sleeve structure 15' is located outside the guide sleeve sealing structure 14' (theoretically, the further outward the guide sleeve is, the greater its ability to withstand eccentric loads), where it is difficult for the emulsion to lubricate. In other words, when the three telescopic columns 100' are raised and lowered, the first guide sleeve structure 13' experiences wet friction, while the second guide sleeve structure 15' experiences dry friction. During dry friction, the second guide sleeve structure 15' wears too quickly, causing the second guide sleeve structure 15' to fail prematurely, affecting the service life of the three telescopic columns 100'. In addition, the protective cover structure 6' and the valve connecting plate 8' of the liquid inlet pipe structure 5' are directly welded to the cylinder tube body structure 7'. During welding, the heat of the weld will change the parent material structure of the cylinder tube body structure 7', thereby affecting the performance of the cylinder tube body structure 7', thereby reducing the service life of the cylinder tube body structure 7'. Last but not least, the column tube structure 11' and the piston 17' are welded to form a piston. When in use, there is ultra-high pressure liquid inside the piston, which is often above 80-90MPa. When other components fail, it will reach above 120MPa. The existence of the weld here seriously restricts the maximum service life of the three telescopic columns 100', and even threatens the safe production of coal mines.

[0037] 1-2 and 4-11 , this embodiment provides a hydraulic support, comprising a high-life three-telescopic column 100 for the hydraulic support, a base 200 , a top beam 300 , a shield beam 400 , a front link 500 , and a rear link 600 The high-life three-telescopic column 100 for the hydraulic support comprises an outer cylinder 1 , a plurality of liquid inlet pipe structures 2 disposed on the outer circumferential wall of the outer cylinder 1 , a multi-stage middle cylinder 3 disposed within the outer cylinder 1 , and a plunger 4 disposed within the middle cylinder 3 .

[0038] In this embodiment, the liquid inlet pipe structure 2 includes a liquid inlet pipe body 21, a pipe joint seat 22 and a valve plate 23, respectively disposed at each end of the liquid inlet pipe body 21. The valve plate 23, the liquid inlet pipe body 21, and the pipe joint seat 22 all define interconnected liquid inlet passages. The pipe joint seat 22 includes a connecting portion 221 connected to the liquid inlet pipe body 21 and a clamping portion 222 that is removably connected to the outer cylinder 1. The clamping portion 222 is capable of being inserted into a slot defined in the cylinder bottom 11 of the outer cylinder 1, and the clamping portion 222 engages with the slot. Specifically, the ends of the liquid inlet pipe body 21 are welded to the pipe joint seat 22 and the valve plate 23, respectively. It should be noted that the welds at both ends of the liquid inlet pipe body 21 can be separated from the cylinder body 12 of the column during welding to the pipe joint seat 22 and the valve plate 23, thereby unrestricting the welding space, which is beneficial for improving the quality of the liquid inlet pipe welds and thereby increasing the service life of the three-telescopic column 100.

[0039] The present invention provides a high-life three-telescopic column 100 for a hydraulic support. A clamping portion 222 is provided on the pipe joint seat 22 of the liquid inlet pipe structure 2. The clamping portion 22 cooperates with the cylinder bottom clamping groove 13 to clamp the liquid inlet pipe structure 2 to the cylinder bottom 11, and ensures that hydraulic oil enters the cylinder bottom 11 through the liquid inlet pipe body 21 and the pipe joint seat 22, and then enters the inner cavity of the outer cylinder 1 to ensure the normal operation of the middle cylinder 3 and the piston 4. Moreover, compared with the welding between the pipe joint seat structure 2' and the cylinder bottom structure 1' in the prior art, the connection with the cylinder bottom 11 through the clamping groove structure reduces the number of welds in conventional positions, avoids welding fatigue or damage to the base material of the cylinder pipe body 12 during welding, which may lead to leakage of hydraulic oil in the three telescopic columns, and then the occurrence of overall failure of the three telescopic columns, thereby greatly improving the reliability and service life of the three telescopic columns.

[0040] Correspondingly, the hydraulic support with three telescopic columns has also undergone corresponding changes. In addition, it cooperates with the base, top beam, shield beam, front connecting rod and rear connecting rod to achieve stable support and improve the service life of the overall hydraulic support.

[0041] Furthermore, as shown in Figures 5-8, the clamping portion 222 comprises a cylindrical body with a first and second stepped end surfaces formed in the axial direction of the cylindrical body, forming a first axial cylindrical wall 2221 and a second axial cylindrical wall 2222 of successively decreasing diameters. A first sealing groove 2223, a second sealing groove 2224, and a pipe joint seat clamping groove 2225, which engages with the cylinder bottom clamping platform 132, are formed along the axial direction of the second axial cylindrical wall 2222. Sealing rings are positioned within each of the first and second sealing grooves 2223 and 2224 to seal the gap between the pipe joint seat 22 and the outer cylinder 1. A pipe joint seat retaining ring 2226 is formed radially outwardly extending between the second sealing groove 2224 and the pipe joint seat clamping groove 2225. In this embodiment, the clamping connection method, in addition to the aforementioned advantages, also facilitates installation and disassembly. If the sealing rings within the first and second sealing grooves 2223 and 2224 fail, they can be replaced directly on-site. The installation and maintenance time is shortened. In addition, the connection method of the clamping structure will not be affected by the number of times used to reduce the service life. At the same time, with the sealing of the two-stage sealing ring, the leakage of hydraulic oil can be further prevented. It should also be noted that the clamping structure is simple, easy to form, stable in connection effect, highly versatile, and low in cost. Specifically, as shown in Figure 6, the pipe joint seat clamping ring 2226 is a split-type clamping ring. In this embodiment, two fan-shaped clamping rings are preferably used. The purpose of setting up this structure is to facilitate installation and forming. In addition, the two clamping rings have an inclined conical surface on one end face close to the connecting portion 221. The purpose of the conical surface is to increase the bearing capacity of the pipe joint seat clamping ring 2226 so that the overall force is better.

[0042] Furthermore, the clamping portion 222 can be bent downward and inward relative to the connecting portion 221 to form an inclined angle, and the inclination angle ranges from 120° to 140°, preferably 135°. The purpose of setting the above-mentioned angle between the clamping portion 222 and the connecting portion 221 is that, firstly, when the hydraulic oil changes direction, it will generate greater pressure at the corner. If an angle range of 120° to 140°, preferably 135°, is formed between the axis of the clamping portion 222 and the axis of the connecting portion 221, the pressure buffer of the hydraulic oil can be effectively reduced, preventing the excessive pressure at this location from causing the pipe joint seat 22 to fail. In addition, this angle can also save the overall space of the liquid inlet pipe structure 2.

[0043] Furthermore, the outer cylinder 1 includes a cylinder bottom 11 hinged to the base 200 of the hydraulic support and a cylinder tube body 12 connected to the cylinder bottom 11. The outer peripheral wall of the cylinder bottom 11 is provided with a plurality of cylinder bottom slots 13 spaced along its circumference, and each cylinder bottom slot 13 is respectively engaged with the engaging portion 222 of the liquid inlet pipe structure 2. The cylinder bottom slot 13 includes a cylinder bottom interface sealing section 131 connected to the inner cavity of the cylinder tube body 12, an engaging slot 135 axially opened along the interface sealing section 13, a cylinder bottom clamping platform 132 and an external interface 133, and the engaging slot 135 is engaged with the pipe joint seat clamping ring 2226. The cylinder tube body 12 is used to accommodate the middle cylinder 3 and the piston 4. In this embodiment, the cylinder bottom slot 13 cooperates with the engaging portion 221 of the pipe joint seat 22 and is tilted at a certain angle.

[0044] Furthermore, a guide assembly 5 is provided between the outer side of the outermost middle cylinder 3 and the inner side of the outer cylinder 1, and the guide assembly 5 includes a guide ring 51 provided at the lower end of the outermost middle cylinder 3. The guide ring 51 includes a first guide ring monomer 511, a second guide ring monomer 512, and a third guide ring monomer 513, which are sequentially spaced along the axial direction of the middle cylinder 3. The first guide ring monomer 511, the second guide ring monomer 512, and the third guide ring monomer 513 are all provided in the guide groove of the outer wall of the middle cylinder 3. In terms of the width in the axial direction of the middle cylinder 3, the first guide ring monomer 511>the second guide ring monomer 512>the third guide ring monomer 513. Specifically, the first guide ring monomer 511, the second guide ring monomer 512, and the third guide ring monomer 513 all use unequal width guide rings according to the eccentric load working condition of the column. The purpose is to increase the service life of each guide ring monomer, and the guide ring monomers are involved according to the actual working conditions.

[0045] Furthermore, the guide assembly 5 also includes a guide sleeve 52 disposed at the upper end of the outermost middle cylinder 3. The guide sleeve 52 includes a first guide sleeve 521, a guide sleeve seal 522, and a second guide sleeve 523, which are spaced apart in the axial direction of the middle cylinder 3. The interior of the second guide sleeve 523 is provided with an oil injection hole 53 connected to the outside. The purpose of providing the guide sleeve 52 is to improve the outer cylinder 1's ability to withstand eccentric loads. The second guide sleeve 523 is disposed at the outermost position, and the additional oil injection hole 53 is provided to lubricate the second guide sleeve 523. Lubricating grease can flow into the second guide sleeve 523 through the oil injection hole 53, thereby reducing the friction coefficient of the second guide sleeve 523 and increasing its service life. It should be noted that an oil injection end cap 54 is provided on the end face of the outer cylinder 1 away from the base 200, and the oil injection end cap 54 can be removed and installed on the end face to facilitate the injection of lubricating oil. The structures of the guide ring 51 and guide sleeve 52 are improved to optimize their performance in handling eccentric load conditions. These improvement measures effectively improve the safety and service life of hydraulic supports and have significant advantages in coal mining.

[0046] Furthermore, the device also includes a protective cover assembly 6 that is sleeved over the liquid inlet pipe body 21. One end of the protective cover assembly 6 is inserted into the fixing hole 134 of the outer cylinder 1, and the other end of the protective cover assembly 6 is detachably connected to the valve plate 23. The protective cover assembly 6 on the liquid inlet pipe body 21 adopts a two-stage detachable fixing structure. Compared with the conventional structure, the weld between the protective cover assembly 6 and the cylinder body 12 is eliminated, thus avoiding damage to the parent material of the cylinder body 12 caused by welding, thereby ensuring the service life of the cylinder body 12. One end of this structure inserts the fixed plug-in column 61 into the fixing hole 134 in the cylinder bottom slot 13, and the other end is fixed to the backing plate 9 welded to the clamp 8 circumferentially sleeved on the outside of the cylinder body 12 via an L-shaped connecting bracket 62 and bolts. Specifically, the protective cover assembly 6 is fixed to the valve plate 23 via screws, and the valve plate 23 is fixed to the backing plate 9 on the protective cover assembly 6 via screws. This avoids damage to the parent material of the cylinder body 12 caused by welding and ensures the service life of the cylinder body 12. In this embodiment, the liquid inlet pipe body 21 and the protective cover assembly 6 are both detachable, so all surfaces of both can be easily treated with anti-corrosion to increase their service life.

[0047] It should be noted that according to GB / T 25974.1-2010, "Hydraulic Supports for Coal Mines," conventional Class B two-column hydraulic supports must pass 13,000 life tests, while Class A supports must pass 27,000 life tests. The three-telescopic columns and the hydraulic support with them in this embodiment have a lifespan tested to a high level of no less than 45,000 life tests, thus providing a long-life triple-telescopic column design.

[0048] Furthermore, the plunger 4 includes a plunger tube 41 that can slide axially relative to the innermost cavity of the central cylinder 3, and a plunger head 42 for sealing the plunger tube 41. The plunger head 42 is integrally formed with the plunger tube 41. The hollow plunger 4 is forged using a one-piece forging process followed by fine finishing to form the integral structure. This eliminates the weld between the plunger tube 41 and the plunger head 42, preventing failure of this weld due to the ultra-high-pressure liquid, thereby significantly extending the service life of the plunger 4.

[0049] Furthermore, a stress groove structure with a circular chamfer transition is formed between the column head 42 and the inner side wall of the column tube 41. Specifically, as shown in Figure 11, the arc transition through R avoids the stress concentration caused by the presence of a sharp point at the root of the blind hole, which may lead to failure at this location. The stress groove is not a simple rounded corner at the root of the blind hole, but the center of the rounded corner is at a certain distance t from the end face, t = (1 / 5 to 1 / 4)R.

[0050] As shown in Figure 12, the weld structure between the cylinder tube 103 and the cylinder bottom 11 is optimized. After a deep hole is drilled in the cylinder wall of the cylinder tube 103, a circular hole as large as the diameter of the deep hole is designed on the end face of the deep hole, and a welding plug 102 is inserted, and then the plug weld 101 is used for welding. After the welding is completed, the end face welding crack of the cylinder tube 103 is processed, and then a narrow gap welding is used with the cylinder bottom of the first-stage middle cylinder 31, that is, the girth weld 10. The welding strength is improved by two welding passes, and the service life of the weld at this position is increased, thereby increasing the service life of the column. A weld bottom groove is left at the root of the girth weld 10. The width t of the groove point is greater than the diameter of the welding wire used. The end face width of the girth weld 10 is usually designed to be 13 mm.

[0051] Furthermore, the overall structure of the pressure balance rod 7 , i.e., the column head 41 and the pressure balance rod 7 are integrated into one, eliminates the static seal between the column head 41 and the pressure balance rod 7 that is subjected to ultra-high pressure, and improves the reliability of the seal at the pressure balance rod 7 .

[0052] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0053] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0054] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0055] In the description of this specification, the terms "one embodiment", "some embodiments", "embodiments", "examples", "specific examples" or "some examples" refer to the specific features, structures, materials or characteristics described in conjunction with the embodiment or example and included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and features of different embodiments or examples, unless they are mutually inconsistent.

[0056] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A three-telescopic column with a long service life for a hydraulic support, characterized by: The invention comprises an outer cylinder (1) and a plurality of liquid inlet pipe structural members (2) arranged on the outer peripheral wall of the outer cylinder (1); the outer cylinder (1) comprises a cylinder bottom (11) hingedly connected to a base (200) of a hydraulic support and a cylinder tube body (12) connected to the cylinder bottom (11); the cylinder tube body (12) is used to accommodate a multi-stage middle cylinder (3); The liquid inlet pipe structural component (2) comprises a liquid inlet pipe body (21), a pipe joint seat (22) and a valve connecting plate (23) respectively arranged at both ends of the liquid inlet pipe body (21), and liquid inlet channels communicating with each other are provided in the valve connecting plate (23), the liquid inlet pipe body (21) and the pipe joint seat (22); The pipe joint seat (22) comprises a connecting portion (221) connected to the liquid inlet pipe body (21) and a clamping portion (222) detachably connected to the outer cylinder (1); The outer peripheral wall of the cylinder bottom (11) is provided with a plurality of cylinder bottom clamping grooves (13) spaced apart along its circumferential direction, and each of the cylinder bottom clamping grooves (13) is respectively clamped with the clamping portion (222) of the liquid inlet pipe structural component (2); The clamping portion (222) can be bent downward and inward relative to the connecting portion (221) to form an inclined angle; the cylinder bottom clamping groove (13) cooperates with the clamping portion (222) and is inclined at a certain angle relative to the axial direction of the cylinder tube body (12); A guide assembly (5) is provided between the outer side of the outermost middle cylinder (3) and the inner side of the outer cylinder (1), and the guide assembly (5) includes a guide ring (51) provided at the lower end of the outermost middle cylinder (3); The guide ring (51) comprises a first guide ring monomer (511), a second guide ring monomer (512) and a third guide ring monomer (513) which are sequentially arranged at intervals along the axial direction of the middle cylinder (3), and the first guide ring monomer (511), the second guide ring monomer (512) and the third guide ring monomer (513) are all arranged in a guide groove on the outer wall of the middle cylinder (3), and the width in the axial direction of the middle cylinder (3) is such that the first guide ring monomer (511) is greater than the second guide ring monomer (512) and is greater than the third guide ring monomer (513); The guide assembly (5) further includes a guide sleeve (52) arranged at the upper end of the outermost middle cylinder (3); The guide sleeve (52) comprises a first guide sleeve (521), a guide sleeve seal (522) and a second guide sleeve (523) which are sequentially arranged in an axial direction of the middle cylinder (3). The second guide sleeve (523) is provided with an oil injection hole (53) in communication with the outside.

2. The three-telescopic column with a long service life for a hydraulic support according to claim 1, characterized in that: The clamping portion (222) comprises a cylinder, and a first-stage step end face and a second-stage step end face are provided in the axial direction of the cylinder, so that the cylinder forms a first axial cylinder wall (2221) and a second axial cylinder wall (2222) whose diameters decrease successively, and a first sealing groove (2223), a second sealing groove (2224) and a pipe joint seat clamping groove (2225) are provided along the axial direction of the second axial cylinder wall (2222); The first sealing groove (2223) and the second sealing groove (2224) are both provided with sealing rings to seal the gap between the pipe joint seat (22) and the outer cylinder (1); A pipe joint seat snap ring (2226) is formed between the second sealing groove (2224) and the pipe joint seat snap groove (2225) and extends outwardly along the radial direction of the cylinder; The cylinder bottom clamping groove (13) comprises a cylinder bottom interface sealing section (131) connected to the inner cavity of the cylinder tube body (12), a clamping groove (135) axially opened along the interface sealing section (131), a cylinder bottom clamping platform (132) and an external interface (133); the clamping groove (135) is clamped with the pipe joint seat clamping ring (2226); and the cylinder bottom clamping platform (132) is matched with the pipe joint seat clamping groove (2225) for clamping.

3. The three-telescopic column with a long service life for a hydraulic support according to claim 2, characterized in that: The pipe joint seat clamping ring (2226) is two fan-shaped clamping rings, and the end faces of the two clamping rings close to the connecting portion (221) are inclined conical surfaces.

4. The three-telescopic column with a long service life for a hydraulic support according to claim 1, characterized in that: It also includes a protective cover assembly (6) sleeved on the liquid inlet pipe body (21), one end of the protective cover assembly (6) is inserted into the fixing hole (134) of the outer cylinder (1), and the other end of the protective cover assembly (6) is detachably connected to the valve connecting plate (23).

5. The three-telescopic column with a long service life for a hydraulic support according to claim 1, characterized in that: The utility model comprises a piston (4) arranged in the middle cylinder (3); the piston (4) comprises a piston tube (41) capable of axially sliding relative to the innermost cavity of the middle cylinder (3) and a piston head (42) for sealing the piston tube (41), and the piston head (42) and the piston tube (41) are integrally formed.

6. The three-telescopic column with a long service life for a hydraulic support according to claim 5, characterized in that: A stress groove structure with an arc chamfer transition is formed between the column head (42) and the inner side wall of the column tube (41).

7. The three-telescopic column with a long service life for a hydraulic support according to claim 1, characterized in that: The inclination angle ranges from 120° to 140°.

8. A hydraulic support, characterized in that: The invention comprises a high-life three-telescopic column (100) for a hydraulic support as described in any one of claims 1 to 7, a base (200), a top beam (300), a shield beam (400), a front connecting rod (500) and a rear connecting rod (600).

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