A down-the-hole hammer self-rotating drilling tool

Abstract

The invention discloses a self-rotating drilling tool for a down-the-hole hammer, comprising a shell, an outer cylinder, an outer piston, an inner piston, an inner cylinder, a core tube and a drill bit, wherein the shell is sleeved on the circumference of the outer cylinder, a first air passage is formed between the inner wall of the shell and the outer wall of the outer cylinder, the outer cylinder is sleeved on the circumference of the outer piston, a second air passage is formed between the inner side wall of the lower part of the outer cylinder and the outer wall of the upper part of the outer piston, the outer piston is sleeved on the circumference of the inner piston, a third air passage is formed between the inner wall of the outer piston and the outer wall of the inner piston, the inner piston is sleeved on the circumference of the inner cylinder, a fourth air passage is formed between the inner wall of the upper part of the inner piston and the outer wall of the lower part of the inner cylinder, the inner cylinder is sleeved on the circumference of the core tube, a fifth air passage is formed between the inner wall of the inner cylinder and the outer wall of the core tube, and the beneficial effects are as follows: a double-piston structure is adopted, the two work independently and do not interfere with each other. The performance is safe and reliable. The overall structure is simple and compact, and the strength is reliable.

Description

Technical Field

[0001] The invention relates to a rotary drilling tool, in particular to a down-the-hole hammer self-rotating drilling tool. Background Art

[0002] At present, pneumatic down-the-hole hammer drilling technology is widely used in hydrological well drilling, geotechnical engineering construction, geological core drilling, oil and gas and mineral resource exploration and development, etc. due to its advantages of fast mechanical drilling speed, clean bottom slag removal, high drilling efficiency, etc., which can effectively improve drilling speed and construction efficiency. However, since the down-the-hole hammer needs the drill rod to drive its rotation, it is difficult to use it directly with directional tools. It is inconvenient to use it in directional wells, horizontal wells and large-reach wells, which seriously restricts the promotion and application of pneumatic down-the-hole hammers in this field.

[0003] The self-rotating drill bit of a down-the-hole hammer utilizes the internal piston kinetic energy to realize the independent rotation of the drill bit or the down-the-hole hammer drill bit, which can greatly improve the stress of the drill string, extend the service life of the drill bit, reduce energy loss and increase the drilling speed, effectively promoting the promotion and application of down-the-hole hammer drilling technology in the fields of directional wells, horizontal wells and extended reach wells. The existing self-rotating drill bits of down-the-hole hammers are improved on the basis of the structure of conventional pneumatic down-the-hole hammers, that is, the impact kinetic energy of the stroke or return stroke of a single piston is used to drive the drill bit to rotate and cut the rock, and to impact and crush the rock. When drilling hard rock, if the piston kinetic energy cannot meet the rock-breaking torque requirement, the drill bit stops rotating and the piston movement is blocked, which may cause the down-the-hole hammer drill bit to fail. In severe cases, it often causes complex underground accidents such as drill jamming. In addition, the reciprocating motion of a single piston is used to drive the drill bit to rotate, so that the impact kinetic energy of the piston is converted into rotational energy. Hard rock formations may have problems such as insufficient impact energy and ineffective footage, and the drill bit has a low service life and poor reliability. Summary of the invention

[0004] The main purpose of the present invention is to solve the problems of poor reliability, low energy utilization, poor piston movement and even easy jamming in the current down-the-hole hammer self-rotating drilling tools, and to provide a down-the-hole hammer self-rotating drilling tool.

[0005] The self-rotating drilling tool of a down-the-hole hammer provided by the present invention comprises a shell, an outer cylinder, an outer piston, an inner piston, an inner cylinder, a core tube and a drill bit, wherein the shell is sleeved on the circumference of the outer cylinder, a first air passage is formed between the inner wall of the shell and the outer wall of the outer cylinder, the outer cylinder is sleeved on the circumference of the outer piston, a second air passage is formed between the inner side wall of the lower part of the outer cylinder and the outer wall of the upper part of the outer piston, the outer piston is sleeved on the circumference of the inner piston, a third air passage is formed between the inner wall of the outer piston and the outer wall of the inner piston, the inner piston is sleeved on the circumference of the inner cylinder, a fourth air passage is formed between the inner wall of the upper part of the inner piston and the outer wall of the lower part of the inner cylinder, The inner cylinder is sleeved on the circumference of the core tube, a fifth air channel is formed between the inner wall of the inner cylinder and the outer wall of the core tube, a first vent is provided on the side wall of the upper part of the outer cylinder, the first vent is connected to the first air delivery channel, a second vent is provided on the top of the second air channel on the side wall of the middle part of the outer cylinder, the second vent is connected to the second air channel, the first vent and the second vent are connected through the first air channel, a first air chamber is provided on the side wall of the outer piston at the bottom of the second air channel, the first air delivery channel, the first vent, the first air channel, the second vent, the second air channel and the first air chamber form a high-pressure gas The first channel of the inner cylinder is provided, and the high-pressure gas entering the first air chamber can push the outer piston to move upward; a third air vent is provided on the side wall of the upper part of the inner cylinder, and the third air vent is connected to the second air supply channel; a fourth air vent is provided on the top of the fourth air channel on the side wall of the middle part of the inner cylinder, and the fourth air vent is connected to the fourth air channel, and the third air vent and the fourth air vent are connected through the fifth air channel; a second air chamber is provided on the side wall of the inner piston at the bottom of the fourth air channel, and the second air supply channel, the third air vent, the fifth air channel, the fourth air vent, the fourth air channel and the second air chamber form a second channel for high-pressure gas. The high-pressure gas entering the second air chamber can push the inner piston to move upward, a third air chamber is opened in the inner cavity of the outer cylinder at the top of the outer piston, and a fourth air chamber is opened in the inner cavity of the outer cylinder at the top of the inner piston. The third air chamber and the fourth air chamber are separated by a partition, and the exhaust ports of the third air chamber and the fourth air chamber are both connected to the third air channel; the bottom of the inner piston abuts against the top of the drill bit, and the inner piston moves up and down to impact the drill bit to move downward, and the bottom of the outer piston is connected to the drill bit through a driving mechanism, and when the outer piston moves upward, the drill bit is driven by the driving mechanism to rotate and drill.

[0006] The shell body is composed of an upper shell body and a lower shell body. A connecting head is installed on the top of the shell body. A check valve is arranged in the inner cavity of the connecting head. A spring is sleeved on the core tube at the lower part of the check valve. The spring can drive the check valve to reset. An outer sleeve is sleeved on the middle part of the inner cavity of the shell body. A spline groove is arranged on the outer wall of the outer sleeve, which cooperates with the spline groove in the middle part of the inner wall of the shell body to limit the rotation of the outer sleeve. A spline groove is arranged on the inner wall of the outer sleeve, which cooperates with the spline in the middle part of the outer wall of the outer piston to limit the rotation of the outer piston. An inner sleeve is sleeved on the core tube corresponding to the outer sleeve. The connection between the lower part of the shell body and the drill bit is respectively equipped with a semicircular card and a limit sleeve.

[0007] A gas distribution plate is assembled on the top of the core tube, and an inner circle air inlet hole and an outer circle air inlet hole are provided on the gas distribution plate, wherein the outer circle air inlet hole is connected to the first gas transmission channel, and the inner circle air inlet hole is connected to the second gas transmission channel, and the top of the partition between the third air chamber and the fourth air chamber is fixedly connected to the bottom of the gas distribution plate, and the lower end of the core tube is connected to a core tube joint, and the lower end of the core tube joint is inserted into the inner cavity of the drill bit, and the inner cavity of the core tube is connected to the inner cavity of the drill bit to form an exhaust channel.

[0008] The bottom of the outer piston is connected to the driving mechanism of the drill bit, which includes a rotating sleeve, wherein the upper part of the rotating sleeve is sleeved on the lower part of the outer piston, and corresponding spiral grooves are provided on the inner side wall of the upper part of the rotating sleeve and the outer side wall of the lower part of the outer piston. The rotating sleeve and the corresponding spiral grooves on the outer piston are connected by embedded balls. When the outer piston reciprocates up and down, the rotating sleeve is driven to rotate by the balls and the spiral grooves. The depth of the spiral grooves provided on the outer side wall of the outer piston becomes deeper successively, so that the rotating sleeve and the outer piston can be locked and separated by the balls. A spline groove is provided on the inner side wall of the bottom of the rotating sleeve, and the bottom of the rotating sleeve is connected to the top of the drill bit through the spline groove. The drill bit can be driven to rotate synchronously during the rotation of the rotating sleeve, and a wear-resistant ring is also provided on the top of the rotating sleeve.

[0009] Working principle of the present invention:

[0010] When the down-the-hole hammer self-rotating drill provided by the present invention is in use, high-pressure air enters the inner cavity of the connector through the pipeline system, pushes open the check valve and reaches the gas distribution plate at the top of the core tube, and the gas is divided into two paths. One path enters the first air chamber through the outer ring air inlet hole, the first air transmission channel, the first air port, the first air channel, the second air port and the second air channel; the other path enters the second air chamber through the inner ring air inlet hole, the second air transmission channel, the third air port, the fifth air channel, the fourth air port and the fourth air channel.

[0011] For the former, the upper annular surface of the outer piston closes the air inlet passage of the third air chamber. The third air chamber is connected to the atmosphere at the bottom of the hole through the third air passage and the drill bit. The pressure in the first air chamber increases, pushing the outer piston upward. The spiral groove provided at the lower part of the outer piston and the spiral groove provided at the upper part of the rotating sleeve squeeze the ball together, so that the ball is in a locked state. The outer piston continues to move upward, and its spiral groove and ball drive the rotating sleeve to rotate, thereby driving the drill bit to rotate synchronously. When the outer piston moves upward to the point where the upper annular surface of the outer piston exceeds the outer cylinder and cooperates with it, high-pressure gas enters the third air chamber to supply it with gas. At this time, the upper end of the outer piston cooperates with the partition to close the third air chamber. The pressure inside the third air chamber increases, and the middle annular surface of the outer piston cooperates with the outer cylinder to close the air inlet passage of the first air chamber. At this time, the lower annular surface of the outer piston exceeds the outer bushing, and the first air chamber is connected to the atmosphere at the bottom of the hole. The outer piston moves upward to the top dead center in a decelerating motion. As high-pressure air continuously enters the third air chamber and acts on the upper end surface of the outer piston, the outer piston moves downward under the combined action of the pressure difference force and gravity, and the spiral groove on the outer piston disengages from the ball, so that the ball is in a free rolling state and the rotating sleeve and the drill bit rotate asynchronously. The outer piston impacts the drill bit downward to break the rock. After the impact, high-pressure gas is delivered to the first air chamber again, the outer piston moves upward, and the ball locks the outer piston and the rotating sleeve, thereby driving the rotating sleeve and the drill bit to rotate synchronously, and the cycle repeats to achieve impact rotary drilling.

[0012] For the latter, after the high-pressure gas enters the second air chamber, the fourth air chamber is connected to the atmosphere through the third air channel and the bottom of the drill hole, and the inner piston moves upward. The gas distribution process of the inner piston is the same as the gas distribution process of the outer piston mentioned above, and will not be repeated. The inner piston reciprocates and impacts the drill bit.

[0013] The above process is reverse circulation drilling. When the improved joint, check valve, spring, core tube, core tube joint and drill bit are used, positive circulation drilling can be performed. The remaining structure of the positive circulation drilling is the same as that of the double piston self-rotating drill tool of the air reverse circulation down-the-hole hammer. The working principle of the double piston self-rotating drill tool of the air positive circulation down-the-hole hammer is similar to that of the above reverse circulation drill tool, with only slight changes: during the gas distribution process, the gas discharged from the first air chamber, the second air chamber, the third air chamber and the fourth air chamber enters the internal channel of the core tube joint through the exhaust holes arranged circumferentially at the lower part of the core tube joint, and is discharged through the drill bit.

[0014] Beneficial effects of the present invention:

[0015] The self-rotating drill tool of the down-the-hole hammer provided by the present invention adopts a double-piston structure. The outer piston drives the drill bit to rotate when it rises, and impacts the drill bit when it descends. The inner piston is only used to impact the drill bit. The two work independently and do not interfere with each other. When drilling hard rock or other complex formations, if the rock-breaking torque exceeds the torque provided by the rotary mechanism of the down-the-hole hammer, even if the outer piston is stuck and the rotary mechanism fails, the inner piston can continue to work and impact rock breaking, realize impact rock breaking and unblocking, and enable the outer piston to resume working, so the performance is safe and reliable. In addition, since the torque is transmitted only through balls, spiral grooves and splines, and wearing parts such as balls are easy to replace, the overall structure is simple and compact, and the strength is reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a cross-sectional view of the overall structure of the down-the-hole hammer self-rotating drilling tool described in the present invention.

[0017] Figure 2 It is a schematic diagram of the shell structure of the present invention.

[0018] Figure 3 It is a schematic diagram of the structure of the outer cylinder and the inner cylinder of the present invention.

[0019] Figure 4 This is a schematic diagram of the structure of the outer piston and the inner piston of the present invention.

[0020] Figure 5 It is a schematic diagram of the structure of the rotating sleeve described in the present invention.

[0021] Figure 6 This is a schematic diagram of the core tube structure of the present invention.

[0022] Figure 7 This is a schematic diagram of the working principle when the outer piston and the inner piston of the present invention are located at the top dead center.

[0023] Figure 8 This is a schematic diagram of the working principle when the outer piston and the inner piston of the present invention are located at the bottom dead center.

[0024] The annotations in the above figure are as follows:

[0025] 1. Shell 2. Outer cylinder 3. Outer piston 4. Inner piston 5. Inner cylinder

[0026] 6. Heart tube 7. Drill bit 8. First airway 9. Second airway 10. Third airway

[0027] 11. Fourth air channel 12. Fifth air channel 13. First air vent 14. First air delivery channel

[0028] 15, second vent 16, first air chamber 17, third vent 18, second air delivery channel

[0029] 19, fourth vent 20, second air chamber 21, third air chamber 22, fourth air chamber

[0030] 23, partition 24, connector 25, check valve 26, spring 27, outer bushing

[0031] 28, inner bushing 29, semicircular card 30, limit sleeve 31, gas distribution plate 32, inner ring air inlet hole

[0032] 33, outer ring air inlet hole 34, core tube joint 35, rotating sleeve 36, spiral groove 37, ball

[0033] 38. Spline groove 39. Wear-resistant ring. DETAILED DESCRIPTION

[0034] See also Figures 1 to 8 As shown:

[0035] The self-rotating drilling tool of a down-the-hole hammer provided by the present invention comprises a shell 1, an outer cylinder 2, an outer piston 3, an inner piston 4, an inner cylinder 5, a core tube 6 and a drill bit 7, wherein the shell 1 is sleeved on the circumference of the outer cylinder 2, a first air passage 8 is formed between the inner wall of the shell 1 and the outer wall of the outer cylinder 2, the outer cylinder 2 is sleeved on the circumference of the outer piston 3, a second air passage 9 is formed between the inner side wall of the lower part of the outer cylinder 2 and the outer wall of the upper part of the outer piston 3, the outer piston 3 is sleeved on the circumference of the inner piston 4, a third air passage 10 is formed between the inner wall of the outer piston 3 and the outer wall of the inner piston 4, the inner piston 4 is sleeved on the circumference of the inner cylinder 5, a fourth air passage 11 is formed between the inner wall of the upper part of the inner piston 4 and the outer wall of the lower part of the inner cylinder 5, and the inner cylinder 5 is sleeved on A fifth air passage 12 is formed between the inner wall of the inner cylinder 5 and the outer wall of the core tube 6 around the core tube 6, a first air vent 13 is provided on the side wall of the upper part of the outer cylinder 2, the first air vent 13 is connected to the first gas delivery channel 14, a second air vent 15 is provided on the top of the second air passage 9 on the side wall of the middle part of the outer cylinder 2, the second air vent 15 is connected to the second air passage 9, the first air vent 13 and the second air vent 15 are connected through the first air passage 8, a first air chamber 16 is provided on the side wall of the outer piston 3 at the bottom of the second air passage 9, the first gas delivery channel 14, the first air vent 13, the first air passage 8, the second air vent 15, the second air passage 9 and the first air chamber 16 form a fifth air passage 12 for high pressure gas. A channel, the high-pressure gas entering the first air chamber 16 can push the outer piston 3 to move upward; a third air vent 17 is opened on the side wall of the upper part of the inner cylinder 5, and the third air vent 17 is connected to the second air supply channel 18. A fourth air vent 19 is opened on the top of the fourth air channel 11 on the side wall of the middle part of the inner cylinder 5, and the fourth air vent 19 is connected to the fourth air channel 11. The third air vent 17 and the fourth air vent 19 are connected through the fifth air channel 12. A second air chamber 20 is opened on the side wall of the inner piston 4 at the bottom of the fourth air channel 11. The second air supply channel 18, the third air vent 17, the fifth air channel 12, the fourth air vent 19, the fourth air channel 11 and the second air chamber 20 form a high-pressure The second channel of gas, the high-pressure gas entering the second air chamber 20 can push the inner piston 4 to move upward, a third air chamber 21 is opened in the inner cavity of the outer cylinder 2 at the top of the outer piston 3, and a fourth air chamber 22 is opened in the inner cavity of the outer cylinder 2 at the top of the inner piston 4. The third air chamber 21 and the fourth air chamber 22 are separated by a partition 23, and the exhaust ports of the third air chamber 21 and the fourth air chamber 22 are both connected to the third air channel 10; the bottom of the inner piston 4 is against the top of the drill bit 7, and the inner piston 4 can move up and down to impact the drill bit 7 to move downward, and the bottom of the outer piston 3 is connected to the drill bit 7 through a driving mechanism. When the outer piston 3 moves upward, the drill bit 7 is driven by the driving mechanism to rotate and drill.

[0036] The shell 1 consists of an upper shell and a lower shell. A connector 24 is installed on the top of the shell 1. A check valve 25 is arranged in the inner cavity of the connector 24. A spring 26 is sleeved on the core tube 6 at the lower part of the check valve 25. The spring 26 can drive the check valve 25 to reset. An outer sleeve 27 is sleeved in the middle part of the inner cavity of the shell 1. A spline groove is provided on the outer wall of the outer sleeve 27, which cooperates with the spline groove in the middle part of the inner wall of the shell 1 to limit the rotation of the outer sleeve 27. A spline groove is provided on the inner wall of the outer sleeve 27, which cooperates with the spline in the middle part of the outer wall of the outer piston 3 to limit the rotation of the outer piston 3. An inner sleeve 28 is sleeved on the core tube 6 corresponding to the outer sleeve 27. The connection between the lower part of the shell 1 and the drill bit 7 is respectively equipped with a semicircular clamp 29 and a limit sleeve 30.

[0037] A gas distribution plate 31 is assembled on the top of the core tube 6, and an inner ring air inlet hole 32 and an outer ring air inlet hole 33 are provided on the gas distribution plate 31, wherein the outer ring air inlet hole 33 is connected to the first gas transmission channel 14, and the inner ring air inlet hole 32 is connected to the second gas transmission channel 18. The top of the partition plate 23 between the third air chamber 21 and the fourth air chamber 22 is fixedly connected to the bottom of the gas distribution plate 31, and the lower end of the core tube 6 is connected to the core tube joint 34, and the lower end of the core tube joint 34 is inserted into the inner cavity of the drill bit 7. The inner cavity of the core tube 6 is connected to the inner cavity of the drill bit 7 to form an exhaust channel.

[0038] The driving mechanism connected to the drill bit 7 at the bottom of the outer piston 3 includes a rotating sleeve 35, wherein the upper part of the rotating sleeve 35 is sleeved on the lower part of the outer piston 3, and corresponding spiral grooves 36 are provided on the inner side wall of the upper part of the rotating sleeve 35 and the outer side wall of the lower part of the outer piston 3. The rotating sleeve 35 and the corresponding spiral grooves 36 on the outer piston 3 are connected by embedded balls 37. When the outer piston 3 reciprocates up and down, the rotating sleeve 35 is driven to rotate by the balls 37 and the spiral grooves 36. The depth of the spiral grooves 36 provided on the outer side wall of the outer piston 3 gradually deepens, so that the rotating sleeve 35 and the outer piston 3 can be locked and separated by the balls 37. A spline groove 38 is provided on the inner side wall of the bottom of the rotating sleeve 35, and the bottom of the rotating sleeve 35 is connected to the top of the drill bit 7 through the spline groove 38. The rotating sleeve 35 can drive the drill bit 7 to rotate synchronously during rotation, and a wear-resistant ring 39 is also sleeved on the top of the rotating sleeve 35.

[0039] Working principle of the present invention:

[0040] When the down-the-hole hammer self-rotating drill provided by the present invention is in use, high-pressure air enters the inner cavity of the connecting head 24 through the pipeline system, pushes open the check valve 25 and reaches the gas distribution plate 31 at the top of the core tube 6. The gas is then divided into two paths, one path enters the first air chamber 16 through the outer ring air inlet hole 33, the first air supply channel 14, the first air port 13, the first air channel 8, the second air port 15 and the second air channel 9; the other path enters the second air chamber 20 through the inner ring air inlet hole 32, the second air supply channel 18, the third air port 17, the fifth air channel 12, the fourth air port 19 and the fourth air channel 11.

[0041] For the former, the upper annular surface of the outer piston 3 closes the air inlet passage of the third air chamber 21, and the third air chamber 21 is connected to the atmosphere at the bottom of the hole through the third air passage 10 and the drill bit 7. The pressure of the first air chamber 16 increases, pushing the outer piston 3 upward, and the spiral groove 36 provided at the lower part of the outer piston 3 and the spiral groove 36 provided at the upper part of the rotating sleeve 35 jointly squeeze the ball 37, so that the ball 37 is in a locked state, and the outer piston 3 continues to move upward, and its spiral groove 36 and ball 37 drive the rotating sleeve 35 to rotate, and then drive the drill bit 7 to rotate synchronously. When the outer piston 3 moves upward to the position where the upper annular surface of the outer piston 3 exceeds the outer cylinder 2 and cooperates with it, high-pressure gas enters the third air chamber 21 to supply it with gas. At this time, the upper end of the outer piston 3 cooperates with the partition 23 to close the third air chamber 21, and the internal pressure of the third air chamber 21 increases. The middle annular surface of the outer piston 3 cooperates with the outer cylinder 2 to close the air inlet passage of the first air chamber 16. At this time, the lower annular surface of the outer piston 3 exceeds the outer bushing 27, and the first air chamber 16 is connected to the atmosphere at the bottom of the hole. The outer piston 3 moves upward to the top dead center with deceleration. As high-pressure air continuously enters the third air chamber 21 and acts on the upper end surface of the outer piston 3, the outer piston 3 moves downward under the combined action of the pressure difference force and gravity, and the spiral groove 36 provided on the outer piston 3 is disengaged from the ball 37, so that the ball 37 is in a free rolling state and the rotating sleeve 35 and the drill bit 7 rotate asynchronously. The outer piston 3 impacts the drill bit downward to break the rock. After the impact, high-pressure gas is delivered to the first air chamber 16 again, and the outer piston 3 moves upward. The ball 37 locks the outer piston 3 and the rotating sleeve 35, thereby driving the rotating sleeve 35 and the drill bit 7 to rotate synchronously, and the cycle repeats to achieve impact rotary drilling.

[0042] For the latter, after the high-pressure gas enters the second air chamber 20, the fourth air chamber 22 is connected to the atmosphere through the third air passage 10 and the bottom of the drill bit 7, and the inner piston 4 moves upward. The gas distribution process of the inner piston 4 is the same as the gas distribution process of the outer piston 3, which will not be described in detail. The inner piston 4 reciprocates and impacts the drill bit 7.

[0043] The above process is reverse circulation drilling. When the improved connector 24, check valve 25, spring 26, core tube 6, core tube joint 34 and drill bit 7 are used, positive circulation drilling can be performed. The remaining structure of the positive circulation drilling is the same as the structure of the double piston self-rotating drilling tool of the air reverse circulation down-the-hole hammer. The working principle of the double piston self-rotating drilling tool of the air positive circulation down-the-hole hammer is similar to that of the above reverse circulation drilling tool, with only slight changes: during the gas distribution process, the gas discharged from the first air chamber 16, the second air chamber 20, the third air chamber 21 and the fourth air chamber 22 enters the internal channel of the core tube joint 34 through the exhaust holes arranged circumferentially at the lower part of the core tube joint 34, and is discharged through the drill bit 7.

Claims

1. A down-the-hole hammer self-rotating drill, characterized in that: The invention comprises a shell, an outer cylinder, an outer piston, an inner piston, an inner cylinder, a core tube and a drill bit, wherein the shell is sleeved on the circumference of the outer cylinder, a first air passage is formed between the inner wall of the shell and the outer wall of the outer cylinder, the outer cylinder is sleeved on the circumference of the outer piston, a second air passage is formed between the inner side wall of the lower part of the outer cylinder and the outer wall of the upper part of the outer piston, the outer piston is sleeved on the circumference of the inner piston, a third air passage is formed between the inner wall of the outer piston and the outer wall of the inner piston, the inner piston is sleeved on the circumference of the inner cylinder, a fourth air passage is formed between the inner wall of the upper part of the inner piston and the outer wall of the lower part of the inner cylinder, the inner cylinder is sleeved on the circumference of the core tube A fifth air channel is formed between the inner wall of the inner cylinder and the outer wall of the core tube, a first vent is provided on the side wall of the upper part of the outer cylinder, the first vent is connected to the first air supply channel, a second vent is provided on the top of the second air channel on the side wall of the middle part of the outer cylinder, the second vent is connected to the second air channel, the first vent and the second vent are connected through the first air channel, a first air chamber is provided on the side wall of the outer piston at the bottom of the second air channel, the first air supply channel, the first vent, the first air channel, the second vent, the second air channel and the first air chamber form a first channel for high-pressure gas, and the gas supply channel, the first vent, the first air channel, the second vent, the second air channel and the first air chamber form a first channel for high-pressure gas. The high-pressure gas entering the first air chamber can push the outer piston to move upward; a third air vent is provided on the side wall of the upper part of the inner cylinder, and the third air vent is connected to the second air supply channel; a fourth air vent is provided on the top of the fourth air channel on the side wall of the middle part of the inner cylinder, and the fourth air vent is connected to the fourth air channel, and the third air vent and the fourth air vent are connected through the fifth air channel; a second air chamber is provided on the side wall of the inner piston at the bottom of the fourth air channel, and the second air supply channel, the third air vent, the fifth air channel, the fourth air vent, the fourth air channel and the second air chamber form a second channel for high-pressure gas. The high-pressure gas entering the second air chamber can push the inner piston to move upward, a third air chamber is opened in the inner cavity of the outer cylinder at the top of the outer piston, and a fourth air chamber is opened in the inner cavity of the outer cylinder at the top of the inner piston. The third air chamber and the fourth air chamber are separated by a partition, and the exhaust ports of the third air chamber and the fourth air chamber are both connected to the third air channel; the bottom of the inner piston abuts against the top of the drill bit, and the up and down movement of the inner piston can impact the drill bit to move downward, and the bottom of the outer piston is connected to the drill bit through a driving mechanism, and when the outer piston moves upward, the drill bit is driven by the driving mechanism to rotate and drill.

2. A down-the-hole hammer self-rotating drill according to claim 1, characterized in that: The shell is composed of an upper shell and a lower shell, a connecting head is installed on the top of the shell, a check valve is arranged in the inner cavity of the connecting head, a spring is sleeved on the core tube at the lower part of the check valve, and the spring can drive the check valve to reset, an outer sleeve is sleeved on the middle part of the inner cavity of the shell, a spline groove is arranged on the outer wall of the outer sleeve, which cooperates with the spline groove in the middle part of the inner wall of the shell, a spline groove is arranged on the inner wall of the outer sleeve, which cooperates with the spline in the middle part of the outer wall of the outer piston, an inner sleeve is sleeved on the core tube corresponding to the outer sleeve, and a semicircular clip and a limit sleeve are respectively arranged at the connection between the lower part of the shell and the drill bit.

3. The self-rotating down-the-hole hammer drilling tool according to claim 1, characterized in that: The top of the core tube is equipped with a gas distribution disk, which is provided with an inner circle air inlet hole and an outer circle air inlet hole, wherein the outer circle air inlet hole is connected to the first gas transmission channel, and the inner circle air inlet hole is connected to the second gas transmission channel. The top of the partition between the third air chamber and the fourth air chamber is fixedly connected to the bottom of the gas distribution disk, and the lower end of the core tube is connected to a core tube joint, and the lower end of the core tube joint is inserted into the inner cavity of the drill bit. The inner cavity of the core tube is connected to the inner cavity of the drill bit to form an exhaust channel.

4. The down-the-hole hammer self-rotating drill according to claim 1, characterized in that: The driving mechanism connected to the drill bit at the bottom of the outer piston comprises a rotating sleeve, wherein the upper part of the rotating sleeve is sleeved on the lower part of the outer piston, and corresponding spiral grooves are provided on the inner side wall of the upper part of the rotating sleeve and the outer side wall of the lower part of the outer piston, and the rotating sleeve and the corresponding spiral grooves on the outer piston are connected by embedded balls, and the rotating sleeve is driven to rotate by the balls and the spiral grooves when the outer piston reciprocates up and down, and the depth of the spiral grooves provided on the outer side wall of the outer piston becomes deeper successively, so that the rotating sleeve and the outer piston can be locked and separated by the balls, and a spline groove is provided on the inner side wall of the bottom of the rotating sleeve, and the bottom of the rotating sleeve is connected to the top of the drill bit through the spline groove, and the drill bit can be driven to rotate synchronously during the rotation of the rotating sleeve, and a wear-resistant ring is also provided on the top of the rotating sleeve.

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