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

Abstract

The present invention relates to the technical field of coal mining support equipment, and in particular to a high-life three-telescopic column for a hydraulic support and a hydraulic support thereof, comprising an outer cylinder, a plurality of liquid inlet pipe structural components, a multi-stage middle cylinder and a piston. The liquid inlet pipe structural component comprises a liquid inlet pipe body, a pipe joint seat and a valve connecting plate. The pipe joint seat comprises a connecting portion and a clamping portion. The clamping portion can be inserted into a clamping groove provided at the bottom of the cylinder of the outer cylinder, and the clamping portion and the clamping groove are clamped in cooperation. The liquid inlet pipe structural component is fixedly connected to the cylinder bottom by clamping the clamping portion in cooperation with the clamping groove at the bottom of the cylinder, and it is ensured that the 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. The welds in the conventional positions are reduced, and the hydraulic oil leakage of the column due to welding fatigue or damage to the cylinder pipe parent material during welding is avoided, and then the overall failure of the column is avoided, which greatly improves the reliability and service life of the three-telescopic column.

Description

Technical Field

[0001] The invention relates to the technical field of coal mining 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 production in coal mines, safety is a red line that can never be crossed. In the process of excavation in coal mines, support equipment is mainly used to support the top of the tunnel. At present, the most important support equipment is hydraulic support. The hydraulic support mainly includes a base, a connecting rod mechanism, a shielding beam, a top beam and a column. Among them, the rear end of the base is hinged to one end of the shielding beam through a connecting rod mechanism, and the other end of the shielding beam is hinged to the top beam. The top beam and the base are arranged parallel to each other, and a column is arranged between the base and the top beam. The top beam is contacted with the coal seam through 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 coal-producing country, China has a vast territory, abundant coal resources, and a variety of coal seam distribution. Therefore, in coal mining, due to different geological structures, there are coal seams of different thicknesses. Coal seams with a thickness of less than 1.3 meters are called thin coal seams, coal seams with a thickness between 1.3 meters and 3.8 meters are called medium-thick coal seams, and coal seams with a thickness greater than 3.8 meters are called thick coal seams. When mining each coal seam, it is necessary to use hydraulic supports that are suitable for the thickness. However, there are still situations where the thickness of the coal seams mined along the excavation direction in the same area varies greatly, that is, in the same working face, along the excavation direction, the thickness of the coal seams ranges from 2 meters to 4.8 meters.

[0004] At present, the columns used in hydraulic supports include single telescopic columns, mechanical extension rod double telescopic columns and hydraulic double telescopic columns. Due to the telescopic ratio limitation of the lifting range of traditional hydraulic supports, in previous mining, for such coal seam thickness changes, only hydraulic supports corresponding to the change of one coal seam thickness can be used for layered and segmented mining, which 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 suitable for them. This leads to the need to frequently replace different models of hydraulic supports as comprehensive mining equipment when mining on the same working face, resulting in great waste in coal mining. Therefore, in recent years, there is a hydraulic support with three telescopic columns on the market, which realizes the use of three telescopic columns on the hydraulic support, breaks through the limitation of the telescopic ratio of traditional telescopic columns, and realizes that a set of hydraulic supports can be used in "thin-medium-thick" coal seams.

[0005] The use of the existing three-telescopic column hydraulic support 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 live column. A liquid inlet pipe structure is directly welded on the outer side of the outer cylinder, and 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, and then the hydraulic oil is passed into the cylinder to achieve the hydraulic oil pushing the remaining middle cylinders and live columns at all levels. However, the existing liquid inlet pipe structure is generally arranged along the longitudinal direction of the cylinder tube, and the outer side wall of the liquid inlet pipe structure is welded to the outer side wall of the cylinder tube, which causes the cylinder tube to be damaged 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 the pipe joint seat structure, and the pipe joint seat structure is welded to the cylinder bottom structure of the bottom cover. Then, due to the long-term use of the column, the welding between the pipe joint seat structure and the cylinder bottom structure will be unstable or fatigued, so that the weld at this location fails, causing hydraulic oil leakage, and then causing the service life of the three telescopic columns to be short. 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 low service life of the three-telescopic column.

[0008] (II) Technical solution

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

[0010] In a first aspect, an embodiment of the present invention provides a three-telescopic column with a long service life for a hydraulic support.

[0011] It comprises an outer cylinder, a plurality of liquid inlet pipe structural members arranged on the outer peripheral wall of the outer cylinder, a multi-stage middle cylinder arranged in the outer cylinder, and a piston arranged in the middle cylinder;

[0012] The liquid inlet pipe structural member comprises a liquid inlet pipe body, a pipe joint seat and a valve connecting plate respectively arranged at both ends of the liquid inlet pipe body, and the valve connecting plate, the liquid inlet pipe body and the pipe joint seat are all provided with mutually connected liquid inlet channels;

[0013] The pipe joint seat comprises a connecting portion connected to the liquid inlet pipe body and a clamping portion detachably connected to the outer cylinder;

[0014] The clamping portion can be inserted into a clamping slot provided at the cylinder bottom of the outer cylinder, and the clamping portion is clamped in cooperation with the clamping slot.

[0015] Optionally, the clamping portion includes a cylinder, and a primary step end face and a secondary step end face are provided in the axial direction of the cylinder, so that the cylinder 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 that cooperates with the cylinder bottom clamping platform are provided along the axial direction of the second axial cylinder wall;

[0016] The first sealing groove and the second sealing groove are both sleeved with sealing rings to seal the gap between the pipe joint seat and the outer cylinder;

[0017] A pipe joint seat clamping ring is formed between the second sealing groove and the pipe joint seat clamping groove and extends outwardly along the radial direction of the cylinder.

[0018] Optionally, the outer cylinder includes a cylinder bottom hinged to the hydraulic support base and a cylinder tube body connected to the cylinder bottom;

[0019] The outer peripheral wall of the cylinder bottom is provided with a plurality of cylinder bottom clamping grooves spaced apart along the circumferential direction thereof, and each of the cylinder bottom clamping grooves is respectively clamped with the clamping portion of the liquid inlet pipe structural member;

[0020] The cylinder bottom clamping groove comprises a cylinder bottom interface sealing section connected to the inner cavity of the cylinder tube body, a clamping clamping groove axially opened along the interface sealing section, a cylinder bottom clamping platform and an external interface, the cylinder bottom clamping groove is clamped with the pipe joint seat clamping ring, and the clamping clamping groove is matched with the pipe joint seat clamping ring;

[0021] The cylinder tube body is used to accommodate the middle cylinder and the piston.

[0022] Optionally, the clamping portion can be bent downward and inward relative to the connecting portion to form an inclined angle, and the range of the inclined angle is between 120° and 140°.

[0023] Optionally, 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 comprises a guide ring provided at the lower end of the outermost middle cylinder;

[0024] 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.

[0025] Optionally, the guide assembly further comprises a guide sleeve arranged at the upper end of the outermost middle cylinder;

[0026] The guide sleeve comprises a first guide sleeve, a guide sleeve seal and a second guide sleeve which are sequentially arranged in an axial direction of the middle cylinder, and an oil injection hole which is connected to the outside is arranged inside the second guide sleeve.

[0027] Optionally, 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.

[0028] Optionally, the piston includes a column tube capable of axially sliding relative to the innermost inner cavity of the middle cylinder and a column head for sealing the column tube, and the column head is integrally formed with the column tube.

[0029] Optionally, a stress groove structure with an arc chamfer transition is formed between the column head and the inner side wall of the column tube.

[0030] In a second aspect, a hydraulic support includes the 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.

[0031] (III) Beneficial effects

[0032] The beneficial effects of the present invention are as follows: a high-life three-telescopic column for a hydraulic support of the present invention is provided with a clamping part on the pipe joint seat of the liquid inlet pipe structure, and the liquid inlet pipe structure is fixedly connected to the cylinder bottom by the clamping part cooperating with the cylinder bottom clamping groove, and the hydraulic oil is ensured to enter the cylinder bottom through the liquid inlet pipe body and the pipe joint seat, and then enter 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 welds in the conventional position, avoids the leakage of hydraulic oil of the column due to welding fatigue or damage to the cylinder tube parent material during welding, and then the occurrence of the overall failure of the column, and greatly improves the reliability and service life of the three-telescopic column.

[0033] 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 cooperated to achieve stable support and improve the service life of the overall hydraulic support. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of a hydraulic support with three telescopic columns according to the present invention in one state;

[0035] Figure 2 It is a structural schematic diagram of the hydraulic support with three telescopic columns of the present invention in another state;

[0036] Figure 3 It is a structural schematic diagram of the existing three telescopic columns;

[0037] Figure 4 It is a schematic structural diagram of three telescopic columns of the present invention;

[0038] Figure 5 It is a structural schematic diagram of the liquid inlet pipe assembly of three telescopic columns of the present invention;

[0039] Figure 6 It is a schematic structural diagram of a pipe joint seat of a liquid inlet pipe assembly of three telescopic columns of the present invention;

[0040] Figure 7 for Figure 6 Schematic diagram of the longitudinal section structure;

[0041] Figure 8 for Figure 4 Schematic diagram of the structure of the bottom part of the middle cylinder;

[0042] Fig. 9 for Figure 4 A schematic diagram of the structure of the middle protective cover assembly;

[0043] Fig.10 for Figure 4 A schematic diagram of the structure of the connection between the middle protective cover assembly and the valve connecting plate;

[0044] Fig.11 It is a schematic diagram of the cross-sectional structure at the head of the active column;

[0045] Fig.12 It is a structural schematic diagram of the welding between the first-stage middle cylinder and the cylinder tube.

[0046] [Description of Reference Numerals]

[0047] 100′: existing three telescopic columns; 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 pipe body structure; 8′: valve connecting plate; 9′: first-level middle cylinder structure; 10′: second-level middle cylinder structure; 11′: column pipe structure; 12′: pressure balance 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;

[0048] 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: clamping slot; 2: liquid inlet pipe structure; 21: liquid inlet pipe body; 22: pipe joint seat; 221: connecting part; 222: clamping part; 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 clamping ring; 23: valve connecting plate; 3: middle cylinder; 3 1: first-stage middle cylinder; 32: second-stage middle cylinder; 4: piston; 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 rod; 8: clamp; 9: pad; 10: ring weld; 101: plug weld; 102: welding plug; 103: cylinder tube;

[0049] 200: base;

[0050] 300: top beam;

[0051] 400: shield beam;

[0052] 500: front connecting rod;

[0053] 600: Rear linkage. DETAILED DESCRIPTION

[0054] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below in conjunction with the accompanying drawings through specific embodiments. Figure 1 The orientation of Figure 1 The position where the middle base 200 is located is defined as "lower"; the position where the top beam 300 is located is defined as "upper".

[0055] 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 low. The main reasons for the low 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 weld of the three telescopic columns 100' to fail due to unstable welding quality or limitations of welding fatigue limit. Moreover, once the weld fails, the three telescopic columns 100' cannot work, and the entire hydraulic support needs 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, which will affect the efficiency of underground operations as a whole and waste time. In addition, 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 completely consistent. Therefore, when the top beam of the hydraulic support is subjected to an eccentric load during the use of the hydraulic support, the three telescopic columns 100' will be subjected to an eccentric load, resulting in the wear degree of the first piston guide ring structure 3' being much higher than that of the second piston guide ring structure 4', further reducing the service life of the three telescopic columns 100'. Secondly, the specifications of the first guide sleeve structure 13' and the second guide sleeve structure 15' are completely the same. Since the first guide sleeve structure 13' is located on the inner side of the guide sleeve sealing structure 14', it is in a position where the emulsion can lubricate, and the second guide sleeve structure 15' is located on the outer side of the guide sleeve sealing structure 14' (theoretically, the closer the guide sleeve is to the outside, the stronger its ability to withstand the eccentric load) and is in a position where the emulsion is difficult to lubricate, that is, the first guide sleeve structure 13' is wet friction when the three telescopic columns 100' are lifted and lowered, while the second guide sleeve structure 15' is 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.

[0056] See also Figure 1-Figure 2 , Figure 4-Figure 11As shown, this embodiment provides a hydraulic support, including a high-life three-telescopic column 100 for the hydraulic support, a base 200, a top beam 300, a shield beam 400, a front connecting rod 500 and a rear connecting rod 600. And a high-life three-telescopic column 100 for the hydraulic support includes an outer cylinder 1, a plurality of liquid inlet pipe structural members 2 arranged on the outer peripheral wall of the outer cylinder 1, a multi-stage middle cylinder 3 arranged in the outer cylinder 1, and a piston 4 arranged in the middle cylinder 3.

[0057] In this embodiment, the liquid inlet pipe structure 2 includes 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 the valve connecting plate 23, the liquid inlet pipe body 21 and the pipe joint seat 22 are all provided with mutually connected liquid inlet channels. The pipe joint seat 22 includes 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 clamping portion 222 can be inserted into the clamping groove provided in the cylinder bottom 11 of the outer cylinder 1, and the clamping portion 222 is clamped in cooperation with the clamping groove. Specifically, the two ends of the liquid inlet pipe body 21 are welded to the pipe joint seat 22 and the valve connecting plate 23 respectively. It should be noted that: when the welds at both ends of the liquid inlet pipe body 21 are respectively welded to the pipe joint seat 22 and the valve connecting plate 23, they can be separated from the cylinder body 12 of the column, thereby making the welding space unrestricted, which is conducive to improving the quality of the liquid inlet pipe welds, thereby improving the service life of the three telescopic columns 100.

[0058] The high-life three-telescopic column 100 for a hydraulic support of the present invention has a clamping portion 222 arranged on the pipe joint seat 22 of the liquid inlet pipe structure 2, and the liquid inlet pipe structure 2 is fixedly connected to the cylinder bottom 11 by the clamping portion 22 cooperating with the cylinder bottom clamping groove 13, and ensures that the 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 welds in the conventional position, avoids the leakage of the hydraulic oil of the three telescopic columns due to welding fatigue or damage to the parent material of the cylinder pipe body 12 during welding, and then the occurrence of the overall failure of the three telescopic columns, which greatly improves the reliability and service life of the three telescopic columns.

[0059] Correspondingly, the hydraulic support with three telescopic columns has also undergone corresponding changes. In addition, the base, top beam, shield beam, front connecting rod and rear connecting rod are coordinated to achieve stable support and improve the service life of the overall hydraulic support.

[0060] Further, see Figure 5-Figure 8As shown, the clamping part 222 includes a cylinder body, and a first-stage step end face and a second-stage step end face are opened in the axial direction of the cylinder body, so that the cylinder body 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 that is matched and clamped with the cylinder bottom clamping platform 132 are opened along the axial direction of the second axial cylinder wall 2222. A sealing ring is sleeved in the first sealing groove 2223 and the second sealing groove 2224 to seal the gap between the pipe joint seat 22 and the outer cylinder 1. A pipe joint seat clamping ring 2226 is formed between the second sealing groove 2224 and the pipe joint seat clamping groove 2225 and extends outward along the radial direction of the cylinder body. In this embodiment, the specific connection method of clamping is adopted, which, in addition to the above advantages, can also facilitate installation and disassembly. Once the sealing of the sealing rings in the first sealing groove 2223 and the second sealing groove 2224 fails, they can be directly replaced on site. The installation and maintenance time is shortened. In addition, the connection mode 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, it can further prevent the leakage of hydraulic oil. It should also be noted that the clamping structure is simple, easy to form, stable in connection effect, high in versatility and low in cost. For details, see Figure 6 As shown, the pipe joint seat clamp ring 2226 is a split type clamp ring, and in this embodiment, two fan-shaped clamp rings are preferably used. The purpose of setting this structure is to facilitate installation and molding. In addition, the two clamp rings have an inclined conical surface at one end surface close to the connecting portion 221. The purpose of the conical surface is to improve the bearing capacity of the pipe joint seat clamp ring 2226 so that the overall force is better.

[0061] Furthermore, the clamping portion 222 can be bent downward and inward relative to the connecting portion 221 to form an inclined angle, and the range of the inclined angle is between 120°-140°, preferably 135°. The purpose of setting the above 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°-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 to prevent the excessive pressure at this location from causing the pipe joint seat 22 to fail; and this angle can also save the overall space of the liquid inlet pipe structure 2.

[0062] Further, 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 circumferential direction, 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 to be inclined at a certain angle.

[0063] 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 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 the guide groove of the outer wall of the middle cylinder 3, and the width in the axial direction of the middle cylinder 3 is as follows: 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 monomer is involved according to the actual working condition.

[0064] Furthermore, the guide assembly 5 also includes a guide sleeve 52 arranged 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 arranged in sequence along the axial direction of the middle cylinder 3. The interior of the second guide sleeve 523 is provided with an oil injection hole 53 which is connected to the outside. The purpose of setting the guide sleeve 52 is to improve the outer cylinder 1's ability to withstand eccentric loads. The second guide sleeve 523 is set at the outermost side, and an additional oil injection hole 53 is added at the same time, so that the second guide sleeve 523 can be lubricated. 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 improving the service life of the second guide sleeve 523. It should be noted that an oil injection end cover 54 is provided on the end face of the outer cylinder 1 away from the base 200, and the oil injection end cover 54 can be disassembled and set on the end face. It is convenient for the injection of lubricating oil.

[0065] Furthermore, it also includes a shield assembly 6 sleeved on the liquid inlet pipe body 21, one end of the shield assembly 6 is inserted into the fixing hole 134 of the outer cylinder 1, and the other end of the shield assembly 6 is detachably connected to the valve connecting plate 23. The shield assembly 6 on the liquid inlet pipe body 21 adopts a two-stage detachable fixing structure, which eliminates the weld between the shield assembly 6 and the cylinder pipe body 12, avoids the damage to the parent material of the cylinder pipe body 12 caused by welding, and ensures the service life of the cylinder pipe body 12. One end of the structure inserts the fixed plug column 61 into the fixing hole 134 on the cylinder bottom card slot 13, and the other end is fixed to the backing plate 9 welded on the hoop 8 circumferentially sleeved on the outside of the cylinder pipe body 12 through the L-shaped connecting frame 62 and bolt connection. Specifically, the shield assembly 6 is fixed to the valve connecting plate 23 by screws, and the valve connecting plate 23 is fixed to the backing plate 9 on the shield assembly 6 by screws, avoiding the damage to the parent material of the cylinder pipe body 12 caused by welding, and ensuring the service life of the cylinder pipe 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 conveniently treated with anti-corrosion to increase the service life.

[0066] It should be noted that, according to GB / T 25974.1-2010 "Hydraulic Support for Coal Mines", a conventional B-type two-column hydraulic support needs to pass 13,000 life test tests, and a Class A support needs to pass 27,000 life test tests. The test life of the three telescopic columns and the hydraulic support with three telescopic columns in this embodiment is increased to a high life level of not less than 45,000 life tests, so it is a three-telescopic column with a long life.

[0067] Furthermore, the plunger 4 includes a plunger tube 41 that can slide axially relative to the inner cavity of the innermost middle cylinder 3 and a plunger head 42 for blocking the plunger tube 41, and the plunger head 42 is integrally formed with the plunger tube 41. The hollow plunger 4 is formed by forging technology, and after integral forging, the integrally formed structure is finely processed, and the weld between the plunger tube 41 and the plunger head 42 of the plunger 4 is eliminated, thereby avoiding the failure of the weld at this position due to the ultra-high pressure liquid, thereby greatly improving the service life of the plunger 4.

[0068] 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. Fig.11 As shown, the arc transition is performed through R, which avoids the stress concentration caused by the sharp point at the root of the blind hole, resulting in failure at this position. The stress groove is not a simple fillet at the root of the blind hole, but the center of the fillet is at a certain distance t from the end face, t = (1 / 5 ~ 1 / 4) R.

[0069] See also Fig.12As shown, 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 larger than 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 adopted with the cylinder bottom of the first-stage middle cylinder 31, that is, the girth weld 10 is welded. 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 bottoming 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.

[0070] Furthermore, the overall structure of the pressure balance rod 7 , that is, 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 .

[0071] 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 as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0072] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0073] In the present invention, unless otherwise clearly specified and limited, when a first feature is “on” or “below” a second feature, it may be 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. Moreover, when a first feature is “above”, “above” or “above” a second feature, it may be that the first feature is directly above or obliquely above the second feature, or it may simply mean that the first feature is higher in level than the second feature. When a first feature is “below”, “below” or “below” a second feature, it may be that the first feature is directly below or obliquely below the second feature, or it may simply mean that the first feature is lower in level than the second feature.

[0074] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations 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 the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0075] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of 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 in that: It 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 two ends of the liquid inlet pipe body (21), and the valve connecting plate (23), the liquid inlet pipe body (21) and the pipe joint seat (22) are all provided with liquid inlet channels that are interconnected; 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, and the range of the inclined angle is between 120° and 140°; 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) comprises 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 arranged in sequence from the lower end to the upper end along the axial direction of the outermost 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 the guide groove of the outer wall of the outermost middle cylinder (3), and the width in the axial direction of the outermost middle cylinder (3) is such that the first guide ring monomer (511)>the second guide ring monomer (512)>the third guide ring monomer (513); The guide assembly (5) further comprises 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 arranged in sequence from the lower end to the upper end along the axial direction of the outermost middle cylinder (3), and the second guide sleeve (523) is provided with an oil injection hole (53) in communication with the outside. The long-life three-telescopic column further comprises a piston (4) arranged in the innermost middle cylinder (3); the piston (4) comprises a cylinder tube (41) capable of axially sliding relative to the inner cavity of the innermost middle cylinder (3) and a cylinder head (42) for blocking the cylinder tube (41), and the cylinder head (42) and the cylinder tube (41) are integrally formed; 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); the center of the arc chamfer of the stress groove is at a certain distance t from the end surface of the column head (42) close to the inner side wall of the column tube (41), t=(1 / 5-1 / 4)R, R being the radius corresponding to the arc chamfer.

2. The three-telescopic column with a long service life for a hydraulic support as claimed in claim 1, characterized in that: The clamping portion (222) comprises a cylinder body, and a first-stage step end face and a second-stage step end face are provided in the axial direction of the cylinder body, so that the cylinder body 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 sleeved with sealing rings to seal the gap between the pipe joint seat (22) and the outer cylinder (1); A pipe joint seat clamping ring (2226) is formed between the second sealing groove (2224) and the pipe joint seat clamping groove (2225) and extends outwardly in 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 clamped with the pipe joint seat clamping groove (2225).

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

4. The three-telescopic column with a long service life for a hydraulic support as claimed in 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) being inserted into the fixing hole (134) of the outer cylinder (1), and the other end of the protective cover assembly (6) being detachably connected to the valve connecting plate (23).

5. A hydraulic support, characterized in that: The invention comprises a three-telescopic column (100) with a long service life for a hydraulic support as described in any one of claims 1 to 4, 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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