Inner cylinder drainage water pressure down-the-hole hammer

Abstract

The utility model discloses an inner cylinder drainage hydraulic down-the-hole hammer, and relates to the technical field of down-the-hole hammers. The device comprises an outer cylinder, an upper joint, a drill bit, an inner cylinder, a piston, a punch hammer and a valve core, a valve seat is arranged in the inner cylinder and above the top of the piston, a valve cover is arranged in the inner cylinder and above the top of the valve seat, the valve core is positioned between the valve seat and the valve cover, one end of the valve core of the valve cover is positioned in a through hole of the valve cover, and the other end of the valve core is propped against the top of the valve core; a valve element upper cavity is formed between the valve element and the valve deck, a valve element lower cavity is formed between the valve element and the valve seat, and a valve element middle cavity is formed in the middle of the valve element. The punch hammer is located in the outer cylinder and connected with the piston rod. The drain hole of the drill bit is matched with the drain hole of the punch hammer. The piston impacts a water flow channel to be straight, the sliding working face of the piston is small, the internal leakage amount is small, and energy efficiency is high.

Description

Technical Field

[0001] The utility model relates to the technical field of down-the-hole hammers, in particular to an inner cylinder drainage hydraulic down-the-hole hammer. Background Art

[0002] Existing hydraulic down-the-hole hammer technology, such as the hydraulic down-the-hole hammer disclosed in patent CN1756888A, uses high-pressure water as the medium to drive the down-the-hole hammer to impact, and has the advantages of a dust-free working environment and high energy efficiency. However, it has the problems of complex structure, difficult manufacturing, small annular piston area, too high water pressure required, small impact energy, large leakage of multiple media on the piston sliding working surface, and low energy efficiency due to tortuous waterways.

[0003] Therefore, there is an urgent need to develop a hydraulic down-the-hole hammer with a simple structure, large impact energy and high energy efficiency. Utility Model Content

[0004] The purpose of the utility model is to overcome the shortcomings of the above-mentioned background technology and to provide a water pressure down-the-hole hammer with an inner cylinder for drainage.

[0005] In order to achieve the above-mentioned purpose, the technical scheme of the utility model is: an inner cylinder drainage hydraulic down-the-hole hammer, characterized in that it includes an outer cylinder, an upper joint, a drill bit, an inner cylinder, a piston, a hammer and a valve core, the upper joint is locked at the top of the outer cylinder, the drill bit is installed in the outer cylinder from the bottom of the outer cylinder, the inner cylinder is installed in the outer cylinder, and the piston is installed in the inner cylinder; a valve seat is arranged in the inner cylinder and above the top of the piston, a valve cover is arranged in the inner cylinder and above the top of the valve seat, the valve core is located between the valve seat and the valve cover, a through hole is opened in the middle of the valve cover, one end of the valve cover valve core is located in the through hole of the valve cover, and the other end is tightly pressed against the top of the valve core;

[0006] The valve core upper cavity is between the valve core and the valve cover, the valve core lower cavity is between the valve core and the valve seat, and the valve core middle cavity is in the middle of the valve core;

[0007] The piston rod of the piston and the lower part of the inner cylinder form a front chamber A of the down-the-hole hammer;

[0008] The piston head, inner cylinder and valve seat bottom of the piston form a back chamber B of the down-the-hole hammer;

[0009] The hammer is located in the outer cylinder, and the piston rod is connected to the hammer;

[0010] The drainage hole of the drill bit matches the drainage hole of the hammer;

[0011] There is a sandwich wall between the outer cylinder and the inner cylinder, and the inner cylinder is provided with a first through hole, a second through hole, and a third through hole;

[0012] The clamp wall is connected to the water inlet hole of the upper joint, the clamp wall is coupled to the valve core middle cavity, and the clamp wall is coupled to the front cavity A of the down-the-hole hammer;

[0013] The first through hole is communicated with the upper cavity of the valve core, the first through hole is coupled with the middle cavity of the valve core, the first through hole is coupled with the piston head necking groove of the piston head, and the bottom of the first through hole leads to the outside of the inner cylinder;

[0014] The second through hole is in communication with the middle cavity of the valve core, and the second through hole is in communication with the rear cavity B of the down-the-hole hammer;

[0015] The third through hole is communicated with the lower cavity of the valve core, and the third through hole is coupled with the front cavity A of the down-the-hole hammer and the necking groove of the piston head.

[0016] In the above technical solution, the inner cylinder is provided with a valve core water inlet hole, a submerged-hole hammer front chamber water inlet hole, a valve core upper chamber drainage hole, a valve core left side drainage hole, a piston head necking connecting hole, a submerged-hole hammer rear chamber water inlet hole, a submerged-hole hammer rear chamber drainage hole, a valve core lower chamber drainage hole, and a pressure feedback hole;

[0017] The clamp wall is coupled with the valve core middle cavity through the valve core water inlet hole, and the clamp wall is coupled with the down-the-hole hammer front cavity A through the down-the-hole hammer front cavity water inlet hole;

[0018] The top of the first through hole is connected to the upper cavity of the valve core through the drainage hole of the upper cavity of the valve core, the first through hole is coupled to the middle cavity of the valve core through the drainage hole on the left side of the valve core, and the first through hole is coupled to the piston head necking groove of the piston head through the piston head necking communication hole;

[0019] The top of the second through hole is connected to the middle cavity of the valve core through the water inlet hole of the back cavity of the down-the-hole hammer, and the bottom of the second through hole is connected to the back cavity B of the down-the-hole hammer through the water discharge hole of the back cavity of the down-the-hole hammer;

[0020] The top of the third through hole is connected to the valve core lower cavity through the valve core lower cavity drainage hole, and the bottom of the third through hole is coupled to the down-the-hole hammer front cavity A and the piston head necking groove through the pressure feedback hole.

[0021] In the above technical solution, a drainage groove is arranged on the piston rod of the piston, and the drainage groove is coupled with the water inlet hole of the front cavity of the down-the-hole hammer.

[0022] In the above technical solution, the drainage hole of the hammer includes a central drainage hole and an oblique drainage hole, one end of the oblique drainage hole is connected to the side wall of the hammer, and the other end is connected to the central drainage hole.

[0023] In the above technical solution, the hammer is provided with a tapered hole, and the piston rod is connected to the tapered hole of the hammer through a tapered head.

[0024] Compared with the prior art, the utility model has the following advantages:

[0025] 1) The utility model has a simple structure and is easy to manufacture.

[0026] 2) The piston impact water flow channel of the utility model is straight, the piston sliding working surface is small, the internal leakage is small and the energy efficiency is high.

[0027] 3) The piston of the utility model is cylindrical, has a large piston area, and has a large single impact energy, which can reduce the water supply pressure.

[0028] In summary, the hydraulic down-the-hole hammer provided by the utility model has the advantages of simple structure, low manufacturing cost, large impact energy, high energy efficiency and low water pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the structure of the utility model when the piston performs an upward return stroke action.

[0030] Figure 2 for Figure 1 Side view of.

[0031] Figure 3 It is a structural schematic diagram of the utility model when the valve core performs upward reversing action.

[0032] Figure 4 for Figure 3 Side view of.

[0033] Figure 5 It is a schematic diagram of the structure of the utility model when the piston performs a downward impact stroke action.

[0034] Figure 6 for Figure 5 Side view of.

[0035] Figure 7 It is a structural schematic diagram of the utility model when the valve core performs downward switching action.

[0036] Figure 8 for Figure 7 Side view of.

[0037] Fig. 9 It is a schematic diagram of the structure of the utility model when performing air defense action.

[0038] Fig.10 for Fig. 9 Side view of.

[0039] Among them, 1-outer cylinder, 2-upper joint, 3-drill bit, 4-inner cylinder, 41-first through hole, 42-second through hole, 43-third through hole, 44-valve core water inlet hole, 45-down-the-hole hammer front chamber water inlet hole, 46-valve core upper chamber drainage hole, 47-valve core left side drainage hole, 48-piston head necking connecting hole, 49-down-the-hole hammer rear chamber water inlet hole, 410-down-the-hole hammer rear chamber drainage hole, 411-valve core lower chamber drainage hole, 412-pressure feedback Hole, 413-drain port, 5-piston, 51-piston rod, 511-drain groove, 52-piston head, 521-piston head neck groove, 6-hammer, 61-center drain hole, 62-oblique drain hole, 63-conical hole, 7-valve core, 71-valve seat, 72-valve cover, 73-valve cover valve core, 74-valve core upper cavity, 75-valve core lower cavity, 76-valve core middle cavity, 8-clamp wall, A-front cavity of submerged hole hammer, B-rear cavity of submerged hole hammer. DETAILED DESCRIPTION

[0040] The following is a detailed description of the implementation of the utility model in conjunction with the accompanying drawings, but they do not constitute a limitation of the utility model and are only used as examples. At the same time, the advantages of the utility model will become clearer and easier to understand through the description.

[0041] Referring to the attached drawings, it can be seen that: an inner cylinder drainage hydraulic down-the-hole hammer, characterized in that it includes an outer cylinder 1, an upper joint 2, a drill bit 3, an inner cylinder 4, a piston 5, a hammer 6 and a valve core 7, wherein the upper joint 2 is locked at the top of the outer cylinder 1, the drill bit 3 is installed in the outer cylinder 1 from the bottom of the outer cylinder 1, the inner cylinder 4 is installed in the outer cylinder 1, and the piston 5 is installed in the inner cylinder 4; a valve seat 71 is arranged in the inner cylinder 4 and above the top of the piston 5, a valve cover 72 is arranged in the inner cylinder 4 and above the top of the valve seat 71, the valve core 7 is located between the valve seat 71 and the valve cover 72, a through hole is opened in the middle of the valve cover 72, one end of the valve cover valve core 73 is located in the through hole of the valve cover 72, and the other end is tightly pressed against the top of the valve core 7;

[0042] The valve core 7 and the valve cover 72 are provided with a valve core upper cavity 74, the valve core 7 and the valve seat 71 are provided with a valve core lower cavity 75, and the valve core 7 has a valve core middle cavity 76 in the middle.

[0043] The piston rod 51 of the piston 5 and the lower part of the inner cylinder 4 form a front chamber A of the down-the-hole hammer;

[0044] The piston head 52 of the piston 5, the inner cylinder 4 and the bottom of the valve seat 71 form a back chamber B of the down-the-hole hammer;

[0045] The hammer 6 is located in the outer cylinder 1, and the piston rod 51 is connected to the hammer 6;

[0046] The drainage hole of the drill bit 3 matches the drainage hole of the hammer 6;

[0047] There is a sandwich wall 8 between the outer cylinder 1 and the inner cylinder 4, and the inner cylinder 4 is provided with a first through hole 41, a second through hole 42, and a third through hole 43;

[0048] The clamp wall 8 is connected to the water inlet hole of the upper joint 2, the clamp wall 8 is coupled to the valve core middle cavity 76, and the clamp wall 8 is coupled to the front cavity A of the down-the-hole hammer;

[0049] The first through hole 41 is connected to the valve core upper cavity 74, the first through hole 41 is coupled to the valve core middle cavity 76, the first through hole 41 is coupled to the piston head necking groove 521 of the piston head 52, and the bottom of the first through hole 41 leads to the outside of the inner cylinder 4;

[0050] The second through hole 42 is in communication with the valve core middle cavity 76, and the second through hole 42 is in communication with the back cavity B of the down-the-hole hammer;

[0051] The third through hole 43 is communicated with the valve core lower cavity 75 , and the third through hole 43 is coupled with the down-the-hole hammer front cavity A and the piston head necking groove 521 .

[0052] The inner cylinder 4 is provided with a valve core water inlet hole 44, a DTH hammer front chamber water inlet hole 45, a valve core upper chamber drainage hole 46, a valve core left side drainage hole 47, a piston head necking connecting hole 48, a DTH hammer rear chamber water inlet hole 49, a DTH hammer rear chamber drainage hole 410, a valve core lower chamber drainage hole 411, and a pressure feedback hole 412;

[0053] The clamp wall 8 is coupled to the valve core middle cavity 76 through the valve core water inlet hole 44, and the clamp wall 8 is coupled to the front cavity A of the down-the-hole hammer through the front cavity water inlet hole 45 of the down-the-hole hammer;

[0054] The top of the first through hole 41 is connected to the valve core upper cavity 74 through the valve core upper cavity drainage hole 46, the first through hole 41 is coupled to the valve core middle cavity 76 through the valve core left drainage hole 47, and the first through hole 41 is coupled to the piston head necking groove 521 of the piston head 52 through the piston head necking communication hole 48; the bottom of the first through hole 41 is connected to the outside of the inner cylinder 4 through the drainage port 413;

[0055] The top of the second through hole 42 is connected to the valve core middle cavity 76 through the water inlet hole 49 of the back cavity of the down-the-hole hammer, and the bottom of the second through hole 42 is connected to the back cavity B of the down-the-hole hammer through the water discharge hole 410 of the back cavity of the down-the-hole hammer;

[0056] The top of the third through hole 43 is connected to the valve core lower cavity 75 through the valve core lower cavity drainage hole 411, and the bottom of the third through hole 43 is coupled to the down-the-hole hammer front cavity A and the piston head necking groove 521 through the pressure feedback hole 412.

[0057] A drainage groove 511 is provided on the piston rod 51 of the piston 5 , and the drainage groove 511 is coupled to the water inlet hole 45 of the front cavity of the down-the-hole hammer.

[0058] The drainage holes of the hammer 6 include a central drainage hole 61 and an oblique drainage hole 62 . One end of the oblique drainage hole 62 is connected to the side wall of the hammer 6 , and the other end is connected to the central drainage hole 61 .

[0059] The hammer 6 has a tapered hole 63 , and the piston rod 51 is connected to the tapered hole 63 of the hammer 6 through a tapered head.

[0060] A cyclic impact method of a hydraulic down-the-hole hammer with inner cylinder drainage, characterized in that it includes the following actions:

[0061] Action 1, piston upward return stroke:

[0062] When the piston 5 rises, the valve core 7 is at the lower end position. At this time, the valve core water inlet hole 44 is closed by the valve core 7, and the high-pressure water flows through the sandwich wall 8 between the outer cylinder 1 and the inner cylinder 4 and the water inlet hole 45 of the front chamber of the down-the-hole hammer to enter the front chamber A of the down-the-hole hammer. The high-pressure water flow exerts an upward thrust on the piston 5, and the piston 5 moves upward. The water in the back chamber B of the down-the-hole hammer flows through the water inlet hole 49 of the back chamber of the down-the-hole hammer, the second through hole 42, the middle chamber 76 of the valve core, the drainage hole 47 on the left side of the valve core, the first through hole 41, the oblique drainage hole 62 and the central drainage hole 61 on the hammer 6, and is discharged to the bottom of the down-the-hole hammer through the drainage hole of the drill bit 3 to wash the drill residue at the bottom of the drill bit;

[0063] Action 2, the valve core changes direction upward:

[0064] The piston 5 moves upward until it reaches the top dead center. The valve core lower chamber 75 is connected to the front chamber A of the submerged-hole hammer through the valve core lower chamber drainage hole 411, the third through hole 43, and the pressure feedback hole 412. The high-pressure water flow is transmitted to the valve core lower chamber 75 to push the valve core 7 upward, completing the upward reversing action.

[0065] After the valve core 7 is reversed upward, high-pressure water flows through the valve core water inlet hole 44, the valve core middle cavity 76, the water inlet hole 49 of the submerged-hole hammer rear cavity, the second through hole 42, and the submerged-hole hammer rear cavity drain hole 410 into the submerged-hole hammer rear cavity B, so that the piston 5 stops moving upward;

[0066] When the valve core 7 moves upward, the water in the valve core upper cavity 74 flows through the valve core upper cavity drain hole 46 and the first through hole 41, and is discharged from the bottom of the first through hole 41; after the valve core 7 is reversed upward, the water in the valve core upper cavity 74 is discharged, and the piston rod of the valve core 7 is thrusted by the high-pressure water flow in the valve core lower cavity 75. The valve core diameter at the lower end of the valve core 7 is larger than the rod diameter at the upper end of the valve cover valve core 73. The valve core 7 is kept at the upper end position and does not move under the action of the high-pressure water flow in the valve core lower cavity 75.

[0067] Action three, piston downward impact stroke:

[0068] After the valve core 7 is reversed upward, the high-pressure water flows through the valve core water inlet hole 44, the valve core middle cavity 76, the water inlet hole 49 of the back cavity of the down-the-hole hammer, the second through hole 42, and the water discharge hole 410 of the back cavity of the down-the-hole hammer into the back cavity B of the down-the-hole hammer. At the same time, the high-pressure water flows through the water inlet hole 45 of the front cavity of the down-the-hole hammer and communicates with the front cavity A of the down-the-hole hammer. Since the piston area of ​​the back cavity B of the down-the-hole hammer is much larger than the area of ​​the front cavity A of the down-the-hole hammer, the piston 5 will move downward rapidly under the action of the high-pressure water flow. At this time, the water flow of the front cavity A of the down-the-hole hammer will enter the back cavity B of the down-the-hole hammer through the sandwich wall 8 between the outer cylinder 1 and the inner cylinder 4, the valve core water inlet hole 44, the valve core middle cavity 76, and the water inlet hole 49 of the back cavity of the down-the-hole hammer; the piston 5 is accelerated to impact the drill bit 3 under the action of the high-pressure water flow, completing one impact on the drill bit 3;

[0069] Action 4, the valve core changes direction downward:

[0070] Before the piston 5 moves downward to impact the drill bit 3, the valve core lower chamber 75 is connected to the piston head necking groove 521 through the valve core lower chamber drainage hole 411, the third through hole 43, and the pressure feedback hole 412. The piston head necking groove 521 is connected to the first through hole 41 through the piston head necking connecting hole 48. The water flow of the valve core lower chamber 75 is discharged to the first through hole 41, and the valve core lower chamber 75 becomes low pressure. The valve core 7 completes the downward reversal under the thrust of the valve cover valve core 73. After the valve core 7 completes the downward reversal, the back chamber B of the down-the-hole hammer is connected to the drainage hole 47 on the left side of the valve core, the pressure of the back chamber B of the down-the-hole hammer is reduced, and the down-the-hole hammer is turned off. The hammer rear chamber B is in a state where water can be discharged; at this time, the valve core upper chamber 74 is connected to the first through hole 41 through the valve core upper chamber drainage hole 46 to maintain low pressure, and the valve cover valve core 73 pushes the valve core 7 to the lower end position and remains stationary under the action of the high-pressure water flow pressure at the upper end; after the valve core 7 is reversed downward, the piston 5 continues to impact downward due to the inertia of high-speed movement until it hits the drill bit 3; after the impact is completed, the high-pressure water flows through the sandwich wall 8 between the outer cylinder 1 and the inner cylinder 4 and the water inlet hole 45 of the front chamber of the down-the-hole hammer into the front chamber A of the down-the-hole hammer, and the piston 5 starts to repeat action one under the push of the water flow pressure in the front chamber A of the down-the-hole hammer and returns upward.

[0071] Action 5: Repeat actions 1 to 4, continuously performing impact drilling and water flushing to remove slag.

[0072] Also includes anti-fly action:

[0073] When the piston 5 impacts downward, if the drill bit 3 is suspended and has a large downward stroke, the piston 5 cannot hit the drill bit 3, and the piston 5 will continue to move downward. Then the piston 5 will close the water inlet hole 45 of the front chamber of the down-the-hole hammer, so that the high-pressure water flow stops entering the front chamber A of the down-the-hole hammer, and the piston 5 stops returning upward. The water closed in the front chamber A of the down-the-hole hammer is discharged from the front chamber A of the down-the-hole hammer through the drainage groove 511, and the piston 5 will stop moving to prevent the down-the-hole hammer from continuously hitting in vain. When the down-the-hole hammer is lowered and contacts the rock surface, the drill bit 3 pushes the piston 5 upward, and the water inlet hole 45 of the front chamber of the down-the-hole hammer is opened again to resume water intake, and the piston 5 returns upward to continue the above-mentioned action one, action two, action three, and action four cycles, and performs continuous impact drilling and flushing and slag removal work.

[0074] By changing the clearance size of the sliding friction surface of different down-the-hole hammer components, the down-the-hole hammer can use clean water, mud, hydraulic oil or air as the high-pressure medium.

[0075] Other parts not described belong to the prior art.

Claims

1. A hydraulic down-the-hole hammer with inner cylinder drainage, characterized in that: The utility model comprises an outer cylinder (1), an upper joint (2), a drill bit (3), an inner cylinder (4), a piston (5), a hammer (6) and a valve core (7), wherein the upper joint (2) is locked at the top of the outer cylinder (1), the drill bit (3) is installed in the outer cylinder (1) from the bottom of the outer cylinder (1), the inner cylinder (4) is installed in the outer cylinder (1), and the piston (5) is installed in the inner cylinder (4); a valve seat (71) is arranged in the inner cylinder (4) and above the top of the piston (5), a valve cover (72) is arranged in the inner cylinder (4) and above the top of the valve seat (71), the valve core (77) is located between the valve seat (71) and the valve cover (72), a through hole is opened in the middle of the valve cover (72), one end of the valve cover valve core (73) is located in the through hole of the valve cover (72), and the other end is pressed against the top of the valve core (7); An upper valve core cavity (74) is formed between the valve core (7) and the valve cover (72), a lower valve core cavity (75) is formed between the valve core (7) and the valve seat (71), and a middle valve core cavity (76) is formed in the middle of the valve core (7); The piston rod (51) of the piston (5) and the lower part of the inner cylinder (4) form a front chamber (A) of the down-the-hole hammer; The piston head (52), the inner cylinder (4) and the bottom of the valve seat (71) of the piston (5) form a back chamber (B) of the down-the-hole hammer; The hammer (6) is located in the outer cylinder (1), and the piston rod (51) is connected to the hammer (6); The drainage hole of the drill bit (3) matches the drainage hole of the hammer (6); A clamping wall (8) is provided between the outer cylinder (1) and the inner cylinder (4), and a first through hole (41), a second through hole (42), and a third through hole (43) are provided in the inner cylinder (4); The clamp wall (8) is connected to the water inlet of the upper joint (2), the clamp wall (8) is coupled to the valve core middle cavity (76), and the clamp wall (8) is coupled to the front cavity (A) of the down-the-hole hammer; The first through hole (41) is communicated with the upper cavity (74) of the valve core, the first through hole (41) is coupled with the middle cavity (76) of the valve core, the first through hole (41) is coupled with the piston head necking groove (521) of the piston head (52), and the bottom of the first through hole (41) leads to the outside of the inner cylinder (4); The second through hole (42) is in communication with the valve core middle cavity (76), and the second through hole (42) is in communication with the back cavity (B) of the down-the-hole hammer; The third through hole (43) is in communication with the valve core lower cavity (75), and the third through hole (43) is coupled with the down-the-hole hammer front cavity (A) and the piston head necking groove (521).

2. The inner cylinder drainage hydraulic down-the-hole hammer according to claim 1, characterized in that: The inner cylinder (4) is provided with a valve core water inlet hole (44), a down-the-hole hammer front chamber water inlet hole (45), a valve core upper chamber drainage hole (46), a valve core left side drainage hole (47), a piston head necking connecting hole (48), a down-the-hole hammer rear chamber water inlet hole (49), a down-the-hole hammer rear chamber drainage hole (410), a valve core lower chamber drainage hole (411), and a pressure feedback hole (412); The clamp wall (8) is coupled to the valve core middle cavity (76) through the valve core water inlet hole (44), and the clamp wall (8) is coupled to the down-the-hole hammer front cavity (A) through the down-the-hole hammer front cavity water inlet hole (45); The top of the first through hole (41) is connected to the upper cavity (74) of the valve core through the drainage hole (46) of the upper cavity of the valve core, the first through hole (41) is coupled to the middle cavity (76) of the valve core through the drainage hole (47) on the left side of the valve core, and the first through hole (41) is coupled to the piston head necking groove (521) of the piston head (52) through the piston head necking communication hole (48); The top of the second through hole (42) is connected to the valve core middle cavity (76) through the water inlet hole (49) of the back cavity of the down-the-hole hammer, and the bottom of the second through hole (42) is connected to the back cavity (B) of the down-the-hole hammer through the water discharge hole (410) of the back cavity of the down-the-hole hammer; The top of the third through hole (43) is connected to the valve core lower chamber (75) through the valve core lower chamber drainage hole (411), and the bottom of the third through hole (43) is coupled to the down-the-hole hammer front chamber (A) and the piston head necking groove (521) through the pressure feedback hole (412).

3. The inner cylinder drainage hydraulic down-the-hole hammer according to claim 2, characterized in that: A drainage groove (511) is provided on the piston rod (51) of the piston (5), and the drainage groove (511) is coupled to the water inlet hole (45) of the front chamber of the down-the-hole hammer.

4. The inner cylinder drainage hydraulic down-the-hole hammer according to claim 3, characterized in that: The drainage hole of the hammer (6) comprises a central drainage hole (61) and an oblique drainage hole (62); one end of the oblique drainage hole (62) is connected to the side wall of the hammer (6) and the other end is connected to the central drainage hole (61).

5. The inner cylinder drainage hydraulic down-the-hole hammer according to claim 4, characterized in that: The hammer (6) is provided with a tapered hole (63), and the piston rod (51) is connected to the tapered hole (63) of the hammer (6) via a tapered head.

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