Dual tube drill and water mill drill

Abstract

The application discloses a double-pipe drilling tool and a water mill drilling machine. The double-pipe drilling tool comprises an outer pipe assembly, an inner pipe assembly and a coring mechanism. A connecting shaft and the inner pipe assembly are sequentially arranged in the outer pipe assembly. A drill bit and a joint are arranged at the front end and the rear end of the outer pipe assembly, respectively. The connecting shaft and the joint are fixedly connected. The joint is used for being connected with an output shaft of a rotary power mechanism. The rotary power mechanism can drive the outer pipe assembly to rotate. The connecting shaft and the inner pipe assembly are rotatably connected through a thrust bearing assembly. The front end of the inner pipe assembly is detachably connected with the coring mechanism. A sealing assembly is further arranged between the inner pipe assembly and the outer pipe assembly. According to the double-pipe drilling tool, the connecting shaft is fixedly connected with the joint and rotatably connected with the inner pipe assembly through the thrust bearing assembly. In this way, the inner pipe assembly can be kept relatively stationary when the outer pipe assembly rotates, and interference wear between the outer pipe assembly and the inner pipe assembly is avoided. Meanwhile, the thrust bearing assembly can effectively disperse axial force and improve the stability of the axial structure.

Description

Technical Field

[0001] This utility model relates to the field of water-grinding drilling rig technology, and in particular to a double-tube drill and a water-grinding drilling rig. Background Technology

[0002] The dual-tube drill bit is the core component of water-cooled drilling rigs for core sampling operations and is widely used in geological exploration, construction engineering, mining and other fields. In the existing technology, the stability of the outer tube assembly and inner tube assembly of the dual-tube drill bit is insufficient. During long-term use, local stress concentration can easily lead to premature wear of key components, shortening the service life of the equipment.

[0003] Therefore, a new type of dual-tube drill bit is needed to solve the above problems. Utility Model Content

[0004] The main purpose of this utility model is to provide a double-tube drill bit and a water-grinding drill to solve the problem of unstable axial structure and easy wear in the existing double-tube drill bit.

[0005] To achieve the above objectives, this utility model provides the following technical solution: According to this application, a dual-tube drill bit is used in a water-grinding drill rig, the water-grinding drill rig including a rotary power mechanism. The dual-tube drill bit comprises an outer tube assembly, an inner tube assembly, and a core-taking mechanism. A connecting shaft and the inner tube assembly are sequentially inserted into the outer tube assembly. A drill bit and a connector are respectively provided at the front and rear ends of the outer tube assembly. The connecting shaft and the connector are fixedly connected. The connector is used to connect to the output shaft of the rotary power mechanism. The rotary power mechanism can drive the outer tube assembly to rotate. The connecting shaft and the inner tube assembly are rotatably connected via a thrust bearing assembly. The front end of the inner tube assembly is detachably connected to the core-taking mechanism.

[0006] According to the dual-tube drill bit of this application, the connecting shaft includes a sleeved shaft and a sleeve, the front end of the sleeve is rotatably connected to the inner tube assembly, the sleeve forms an installation cavity, the shaft and the thrust bearing assembly are disposed in the installation cavity, the thrust bearing assembly includes a thrust bearing, a bushing and a tension ring both sleeved on the shaft, there are two thrust bearings, the two thrust bearings are spaced apart along the axial direction of the installation cavity, the tension ring is sandwiched between the two thrust bearings, and one of the thrust bearings closer to the inner tube assembly is sleeved outside the bushing.

[0007] Optionally, a sealing assembly is further provided between the shaft and the sleeve. The sealing assembly includes a limiting member and a sealing ring. The sealing ring and the limiting member are both sleeved on the shaft, and the sealing ring abuts against the thrust bearing near the joint.

[0008] Optionally, the sleeve is provided with a nut and a round shaft nut near the front end of the shaft. The nut and the round shaft nut are connected by the nut and the round shaft nut. A pin is provided at the front end of the shaft, and the pin is threadedly connected to the round shaft nut and the shaft.

[0009] Optionally, a one-way valve is provided at the end of the sleeve. The one-way valve includes a ball valve seat, in which a movable steel ball is fitted. The ball valve seat includes a seat body and a flow passage formed at the center of the seat body. The inner wall of the seat body has a conical sealing part that mates with the steel ball. When the steel ball is in contact with the conical sealing part, the steel ball closes the flow passage. At least two guide grooves are also formed on the joint. A flushing channel is formed between the outer tube assembly and the inner tube assembly. The guide grooves, the flushing channel, and the flow passage are connected in sequence.

[0010] Optionally, the core extraction mechanism includes a retaining ring seat and a retaining ring. The outer wall of the retaining ring is conical, and the retaining ring seat has a conical inner wall adapted to the retaining ring. The inner wall of the front end of the retaining ring is provided with a serrated anti-disengagement part protruding inward along the circumferential direction. The anti-disengagement part is distributed in a continuous spiral shape along the circumferential direction of the retaining ring. The retaining ring can elastically deform to open or retract and reset.

[0011] Optionally, the inner tube assembly further includes a main body and a transition part connected sequentially along the axial direction. One end of the transition part is connected to the main body, and the other end is detachably connected to the snap ring seat. The outer peripheral surface of the transition part is spaced apart from the inner wall of the outer tube assembly.

[0012] According to the dual-tube drill bit of this application, the outer tube assembly includes an outer tube, the drill bit is threadedly connected to the outer tube, the drill bit is inlaid with a carbide distributed in a spiral pattern, and a reamer is sleeved on one end of the outer tube assembly near the drill bit, and a gasket is sandwiched between the reamer and the drill bit.

[0013] The water-grinding drill according to this application includes: The system includes a rotary power mechanism, a traveling mechanism, a guide rail, and the aforementioned double-tube drill bit. The output end of the rotary power mechanism is connected to the joint of the double-tube drill bit. The rotary power mechanism is mounted on the traveling mechanism, which is mounted on the guide rail. The traveling mechanism is used to drive the rotary power mechanism to reciprocate along the guide rail.

[0014] The technical solution provided by the utility model embodiments has the following advantages compared with the prior art: The dual-tube drill bit provided in this embodiment of the utility model has an outer tube assembly connected to a rotary power mechanism via a connector. Driven by the rotary power mechanism, it rotates to drill into the rock. The connecting shaft is fixedly connected to the connector and rotatably connected to the inner tube assembly via a thrust bearing assembly. This allows the inner tube assembly to remain relatively stationary when the outer tube assembly rotates, avoiding interference and wear between them. At the same time, the thrust bearing assembly can effectively disperse axial force, reduce the load on a single component, and improve the stability of the axial structure. The detachable connection between the front end of the inner tube assembly and the core sampling mechanism facilitates maintenance and replacement, avoiding the need for complete replacement due to local damage, further optimizing the durability of the structure. The drill bit at the front end of the outer tube assembly and the connector at the rear end form a relatively balanced axial force. Combined with the rotational engagement between the connecting shaft and the inner tube assembly, the entire dual-tube drill bit is subjected to balanced force during operation, reducing vibration and wear caused by structural instability, while improving the stability and reliability of the core sampling process. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the rear end portion of a dual-tube drill bit structure provided in an embodiment of the present utility model.

[0016] Figure 2 This is a schematic diagram of the front end portion of a dual-tube drill bit in the extension direction, provided for an embodiment of this utility model.

[0017] Figure 3 This is a schematic diagram of a water-cooled drilling machine provided for an embodiment of the present utility model.

[0018] Labeling Explanation: 1. Dual-tube drill bit; 10. Outer tube assembly; 11. Outer tube; 12. Carbide; 13. Reamer; 20. Inner tube assembly; 21. Main body; 22. Connector; 30. Core sampling mechanism; 31. Snap ring seat; 32. Snap ring; 40. Connecting shaft; 41. Shaft; 42. Sleeve; 421. Nut pin ring; 422. Round shaft nut; 423. Pin; 43. Check valve; 43. Ball valve seat; 433. Flow channel. Drill bit 50, connector 60, guide groove 61, thrust bearing assembly 70, thrust bearing 71, bushing 72, tension ring 73, sealing assembly 80, limit component 81, sealing ring 82, rotary power mechanism 2, traveling mechanism 3, guide rail 4. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0020] like Figure 1 and Figure 2As shown, the dual-tube drill bit 1 according to an embodiment of this application is used in a water-grinding drill. The water-grinding drill includes a rotary power mechanism 2. The dual-tube drill bit 1 includes an outer tube assembly 10, an inner tube assembly 20, and a core sampling mechanism 30. A connecting shaft 40 and an inner tube assembly 20 are sequentially inserted into the outer tube assembly 10. A drill bit 50 and a connector 60 are respectively provided at the front end and rear end of the outer tube assembly 10. The connecting shaft 40 and the connector 60 are fixedly connected. The connector 60 is used to connect to the output shaft of the rotary power mechanism 2. The rotary power mechanism 2 can drive the outer tube assembly 10 to rotate. The connecting shaft 40 and the inner tube assembly 20 are rotatably connected through a thrust bearing assembly 70. The front end of the inner tube assembly 20 is detachably connected to the core sampling mechanism 30.

[0021] According to the embodiments of this application, the outer tube assembly 10 is connected to the rotary power mechanism 2 via a connector 60 and rotates to drill into the rock under the drive of the rotary power mechanism 2. The connecting shaft 40 is fixedly connected to the connector 60 and rotatably connected to the inner tube assembly 20 via a thrust bearing assembly 70. This allows the inner tube assembly 20 to remain relatively stationary when the outer tube assembly 10 rotates, avoiding interference and wear between the two. At the same time, the thrust bearing assembly 70 can effectively disperse axial force, reduce the load on a single component, and improve the stability of the axial structure. The detachable connection between the front end of the inner tube assembly 20 and the core sampling mechanism 30 facilitates maintenance and replacement, avoiding the need for overall replacement due to local damage, further optimizing the durability of the structure. The drill bit 50 at the front end of the outer tube assembly 10 and the connector 60 at the rear end form a relatively balanced axial force. Combined with the rotational engagement between the connecting shaft 40 and the inner tube assembly 20, the entire double tube drill 1 is subjected to balanced force during operation, reducing vibration and wear caused by structural instability, and improving the stability and reliability of the core sampling process.

[0022] like Figure 1 As shown, according to an embodiment of this application, the dual-tube drill bit 1 has a connecting shaft 40 including a sleeved shaft 41 and a sleeve 42. The front end of the sleeve 42 is rotatably connected to the inner tube assembly 20. The sleeve 42 forms an installation cavity. The shaft 41 and the thrust bearing assembly 70 are disposed in the installation cavity. The thrust bearing assembly 70 includes thrust bearings 71, a bushing 72, and a tension ring 73, all of which are sleeved on the shaft 41. There are two thrust bearings 71, which are spaced apart along the axial direction of the installation cavity. The tension ring 73 is sandwiched between the two thrust bearings 71. One thrust bearing 71 closer to the inner tube assembly 20 is sleeved outside the bushing 72.

[0023] The connecting shaft 40 is sleeved with the sleeve 42 via the shaft 41. The front end of the sleeve 42 is rotatably connected to the inner tube assembly 20. The mounting cavity between the shaft 41 and the sleeve 42 provides a closed mounting space for the thrust bearing assembly 70, effectively protecting the thrust bearing assembly 70 from external impurities. The two thrust bearings 71 in the thrust bearing assembly 70 are axially spaced along the mounting cavity and pre-tightened by the tension ring 73. They jointly bear the unidirectional axial force generated by the outer tube assembly 10 during rotary drilling, reducing the load on a single thrust bearing 71. The elastic pre-tightening of the tension ring 73 eliminates the gap between the two thrust bearings 71, suppressing vibration and axial movement, and reducing impact load.

[0024] Among them, a thrust bearing 71 near the inner tube assembly 20 is sleeved on the outside of the bushing 72. The bushing 72 provides radial rigid support for the thrust bearing 71, restricts the radial displacement of the thrust bearing 71, ensures its coaxiality with the shaft 41 and the sleeve 42, and avoids additional stress caused by eccentricity, which would aggravate wear. At the same time, the bushing 72, through its cooperation with the inner tube assembly 20, stably transmits the axial force borne by the thrust bearing 71 to the inner tube assembly 20, forming a force transmission path from the outer tube assembly 10 to the connecting shaft 40, and then through the thrust bearing assembly 70 to the inner tube assembly 20, making the axial force distribution more balanced.

[0025] The shaft 41 provides inner positioning for the two thrust bearings 71, while the sleeve 42 constrains the thrust bearing assembly 70 from the outside. The connecting shaft 40 and the inner tube assembly 20 achieve low-friction rotational engagement through the thrust bearing assembly 70. This ensures that the inner tube assembly 20 remains relatively stationary when the outer tube assembly 10 rotates during drilling, preventing torsional damage to the rock core. Furthermore, the reinforced positioning of the thrust bearings 71 by the sleeve 72 and the pre-tightening buffer of the tension ring 73 significantly improve the stability of the axial structure, reduce wear caused by component shaking and eccentricity, and thus extend the service life of the dual-tube drill bit 1.

[0026] like Figure 1 As shown, in some embodiments, a nut pin ring 421 and a round shaft nut 422 are provided on the sleeve 42 near the front end of the shaft 41. The nut pin ring 421 connects the sleeve 42 and the round shaft nut 422. A pin 423 is provided at the front end of the shaft 41. The pin 423 is threadedly connected to the round shaft nut 422 and the shaft 41.

[0027] The nut pin tightening ring 421 connects the sleeve 42 and the round shaft 422. The round shaft 422 is fixed in the preset position of the sleeve 42 by the thread preload, preventing the round shaft 422 from moving axially or rotating circumferentially along the sleeve 42. The pin 423 at the front end of the shaft 41 passes radially through the round shaft 422 and is threaded to the shaft 41, rigidly locking the round shaft 422 and the shaft 41 into one, so that there is no relative displacement between the two when transmitting torque and axial force. This ensures that the torque generated by the rotation of the outer tube assembly 10 and the axial force of the drill bit 50 can be stably transmitted to the thrust bearing assembly 70 through this connection path, avoiding stress concentration and component wear caused by local loosening. At the same time, the detachable threaded connection design makes it easy to remove the pin 423 and the nut pin tightening ring 421 to separate the sleeve 42 and the shaft 41 without damaging the overall structure, improving the maintenance convenience and component reuse rate of the dual tube drill 1.

[0028] like Figure 1 As shown, in some embodiments, a sealing assembly 80 is also provided between the shaft 41 and the sleeve 42. The sealing assembly 80 includes a limiting member 81 and a sealing ring 82. Both the sealing ring 82 and the limiting member 81 are sleeved on the shaft 41, and the sealing ring 82 abuts against the thrust bearing 71 near the joint 60. Both the sealing ring 82 and the limiting member 81 are sleeved on the shaft 41 to ensure coaxiality with the shaft 41 and avoid sealing blind spots caused by eccentricity. The sealing ring 82 abuts against the thrust bearing 71 near the joint 60. The rigid end face of the thrust bearing 71 is used to position the axial position of the sealing ring 82 to prevent it from being displaced due to vibration or pressure when the shaft 41 and the sleeve 42 move relative to each other. At the same time, the flatness of the thrust bearing 71 is used to ensure that the sealing ring 82 fits tightly. The limiting member 81 constrains the sealing ring 82 from the other side, limiting its excessive deformation or radial displacement, so that the sealing ring 82 is always in close contact with the inner wall of the sleeve 42 and the outer peripheral surface of the shaft 41, blocking external impurities or flushing fluid from entering the mounting cavity through the gap between the shaft 41 and the sleeve 42, and preventing the leakage of lubricating medium in the mounting cavity.

[0029] like Figure 1 As shown, in some embodiments, a one-way valve 43 is provided at the end of the sleeve 42. The one-way valve 43 includes a ball valve seat 431, in which a movable steel ball is fitted. The ball valve seat 431 includes a seat body and a flow passage 433 formed at the center of the seat body. A conical sealing part that cooperates with the steel ball is formed on the inner wall of the seat body. When the steel ball is in contact with the conical sealing part, the steel ball closes the flow passage 433. At least two guide grooves 61 are also formed on the connector 60. A flushing channel is formed between the outer tube assembly 10 and the inner tube assembly 20. The guide grooves 61, the flushing channel and the flow passage 433 are connected in sequence.

[0030] The flow channel 433 at the center of the base provides a flow path for the flushing fluid. When the steel ball is in contact with the conical sealing part on the inner wall of the base, the flow channel 433 is closed, preventing the flushing fluid from flowing back. The guide groove 61 at the joint 60 introduces the flushing fluid into the flushing channel between the outer tube assembly 10 and the inner tube assembly 20, and then connects with the flow channel 433 through the flushing channel, forming a continuous flushing path from the joint 60 to the drill bit 50. This structural design allows the flushing fluid to push the steel ball away from the conical sealing part under pressure, opening the flow channel 433 to achieve cooling of the drill bit 50 and carrying out the rock cuttings. When the flushing fluid pressure disappears, the steel ball falls back to the conical sealing part under gravity or residual pressure, automatically closing the flow channel 433 to prevent rock cuttings or external media from flowing back into the inner tube assembly 20, avoiding blockage of the flushing channel and contamination of the rock core. The multi-channel design of the guide channel 61 ensures that the flushing fluid is evenly distributed to the annular flushing channel, enhancing the flushing effect; while the one-way valve 43 achieves one-way flow control of the flushing fluid through the dynamic sealing cooperation between the movable steel ball and the conical sealing part, which not only ensures effective chip removal during drilling, but also prevents backflow pollution when the machine stops, thus improving the working reliability and core quality of the dual-tube drill bit 1 under complex geological conditions.

[0031] like Figure 2 As shown, in some embodiments, the core extraction mechanism 30 includes a retaining ring seat 31 and a retaining ring 32. The outer wall of the retaining ring 32 is conical, and the retaining ring seat 31 has a conical inner wall adapted to the retaining ring 32. The inner wall of the front end of the retaining ring 32 is provided with a serrated anti-disengagement part protruding inward along the circumferential direction. The anti-disengagement part is distributed in a continuous spiral along the circumferential direction of the retaining ring 32. The retaining ring 32 can be elastically deformed to open or retract and reset.

[0032] The conical outer wall of the retaining spring 32 fits against the conical inner wall of the retaining spring seat 31. When the retaining spring seat 31 moves axially with the inner tube assembly 20, the conical fit forces the retaining spring 32 to radially contract or expand and deform. The serrated anti-detachment part on the inner wall of the front end of the retaining spring 32 is continuously spirally distributed circumferentially. When the rock core enters the retaining spring 32, the anti-detachment part can elastically open to allow the rock core to pass smoothly. When the rock core stops moving or needs to be removed, the serrated structure of the anti-detachment part forms a continuous circumferential clamping force through the spiral distribution, embedding into the outer circumferential surface of the rock core and preventing the rock core from retreating or falling out. The retaining spring 32 can automatically adjust the clamping force according to the diameter of the rock core to adapt to rock cores of different sizes. At the same time, the spirally distributed anti-detachment part disperses stress through continuous circumferential contact, protecting the integrity of the rock core.

[0033] like Figure 2 As shown, in some embodiments, the inner tube assembly 20 further includes a main body portion 21 and a transition portion 22 connected sequentially along the axial direction. One end of the transition portion 22 is connected to the main body portion 21, and the other end is detachably connected to the snap ring seat 31. The outer peripheral surface of the transition portion 22 is spaced apart from the inner wall of the outer tube assembly 10.

[0034] The main body 21 and the adapter 22 are connected sequentially along the axial direction. The main body 21 provides the core rigid support for the inner tube assembly 20, while the adapter 22 serves as a connecting bridge. One end is firmly connected to the main body 21 to ensure the overall axial continuity of the inner tube, and the other end is detachably connected to the snap ring seat 31. This allows the core sampling mechanism 30 to be disassembled and assembled without involving the inner tube main body 21, facilitating the separate replacement or maintenance of the snap ring seat 31 and snap ring 32, thus improving operational efficiency. The outer peripheral surface of the adapter 22 is spaced from the inner wall of the outer tube assembly 10. This space is connected to the flushing channel between the outer tube assembly 10 and the inner tube assembly 20, ensuring that the flushing fluid can flow smoothly through the outer periphery of the adapter 22. This avoids blocking the flushing path due to the adapter 22, ensuring continuous cooling of the drill bit 50 and effective removal of rock cuttings by the flushing fluid.

[0035] like Figure 2 As shown, according to an embodiment of this application, the double-tube drill bit 1 includes an outer tube 11, a drill bit 50 is threadedly connected to the outer tube 11, and a carbide 12 distributed in a spiral pattern is embedded on the drill bit 50. A hole expander 13 is sleeved on one end of the outer tube assembly 10 near the drill bit 50, and a gasket is sandwiched between the hole expander 13 and the drill bit 50.

[0036] The drill bit 50 and the outer tube 11 are connected by threads to form a detachable structure, which facilitates the individual replacement of the drill bit 50 after wear, and ensures the coaxiality and connection rigidity of the drill bit 50 and the outer tube 11 through the preload of the threaded pair, making the torque transmission during drilling more stable.

[0037] The spirally distributed cemented carbide 12 embedded on the drill bit 50 increases the contact area between the cutting edge and the rock through the spiral trajectory, forming a continuous breaking path during rotary drilling and improving rock breaking efficiency. At the same time, the spirally distributed cemented carbide 12 can also guide rock cuttings to be discharged along the spiral groove, reducing the accumulation of rock cuttings at the bottom of the borehole. The reamer 13, which is sleeved on the end of the outer tube 11 near the drill bit 50, performs secondary finishing on the borehole wall through the synergistic action with the drill bit 50, ensuring the consistency of the hole diameter and avoiding frictional resistance caused by the direct contact of the outer tube 11 with the borehole wall.

[0038] The gasket sandwiched between the reamer 13 and the drill bit 50 serves two purposes: firstly, it compensates for the assembly gap between the two through elastic deformation, enhancing the tightness of the connection; secondly, it acts as a buffer when the drill bit 50 is subjected to impact loads, reducing the impact of vibration on the outer tube assembly 10 and extending the service life of the outer tube 11.

[0039] like Figure 3As shown, the water-grinding drill according to an embodiment of this application includes a rotary power mechanism 2, a traveling mechanism 3, a guide rail 4, and the aforementioned double-tube drill bit 1. The output end of the rotary power mechanism 2 is connected to the connector 60 of the double-tube drill bit 1. The rotary power mechanism 2 is mounted on the traveling mechanism 3, and the traveling mechanism 3 is mounted on the guide rail 4. The traveling mechanism 3 is used to drive the rotary power mechanism 2 to reciprocate along the guide rail 4.

[0040] The rotary power mechanism 2 includes a power source, a reduction gear assembly, and a transmission connector. The power source provides initial rotational power, and after the speed and torque are adjusted by the reduction gear assembly, the power source is connected to the joint 60 of the double-tube drill bit 1 through the transmission connector, such as a coupling or gear pair, to form a transmission.

[0041] The walking mechanism 3 includes a drive unit, a guide slider, and a transmission component. The drive unit converts power into linear motion through the transmission component. The drive unit can be a gear motor, and the transmission component can be a rack and pinion meshing or a lead screw and nut engaging.

[0042] The rotary power mechanism 2, through its transmission connection with the joint 60 of the dual-tube drill string 1, stably transmits power to the dual-tube drill string 1, driving it to perform rotary drilling operations and ensuring the continuous and efficient cutting operation of the drill bit 50. The rotary power mechanism 2 is mounted on the traveling mechanism 3. The traveling mechanism 3, in conjunction with the guide rail 4, forms a movable support system. The traveling mechanism 3 drives the rotary power mechanism 2 to reciprocate along the guide rail 4, realizing the axial feed and retraction of the dual-tube drill string 1. The guiding effect of the guide rail 4 ensures the straightness of the drilling direction, avoiding borehole skew caused by feed deviation. The cooperation between the rotary power mechanism 2 and the traveling mechanism 3 allows the dual-tube drill string 1 to obtain stable rotary cutting force and control the drilling speed through uniform feed, adapting to the operational needs under different geological conditions.

[0043] The specific embodiments of the utility model have been described in detail above, but they are only examples, and the utility model is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications or substitutions to the utility model are also within the scope of the utility model. Therefore, all equivalent transformations, modifications, and improvements made without departing from the spirit and principles of the utility model should be covered within the scope of the utility model.

Claims

1. A double-tube drill bit for a water-grinding drill rig, the water-grinding drill rig comprising a rotary power mechanism, characterized in that, The dual-tube drill bit includes an outer tube assembly, an inner tube assembly, and a core sampling mechanism. A connecting shaft and the inner tube assembly are sequentially inserted into the outer tube assembly. A drill bit and a connector are respectively provided at the front and rear ends of the outer tube assembly. The connecting shaft and the connector are fixedly connected. The connector is used to connect to the output shaft of the rotary power mechanism. The rotary power mechanism can drive the outer tube assembly to rotate. The connecting shaft and the inner tube assembly are rotatably connected through a thrust bearing assembly. The front end of the inner tube assembly is detachably connected to the core sampling mechanism. The connecting shaft includes a sleeve and a core. The front end of the sleeve is rotatably connected to the inner tube assembly. The sleeve forms a mounting cavity. The core and the thrust bearing assembly are disposed in the mounting cavity. The thrust bearing assembly includes a thrust bearing, a bushing, and a tension ring, all sleeved on the core. There are two thrust bearings, which are spaced apart along the axial direction of the mounting cavity. The tension ring is sandwiched between the two thrust bearings. One thrust bearing closer to the inner tube assembly is sleeved outside the bushing. The end of the sleeve is provided with a one-way valve, the one-way valve includes a ball valve seat, a movable steel ball is inserted in the ball valve seat, the ball valve seat includes a seat body and a flow passage formed in the center of the seat body, the inner wall of the seat body is formed with a conical sealing part that cooperates with the steel ball, when the steel ball is in contact with the conical sealing part, the steel ball closes the flow passage, at least two guide grooves are also formed on the joint, a flushing channel is formed between the outer tube assembly and the inner tube assembly, and the guide grooves, the flushing channel and the flow passage are connected in sequence; The core extraction mechanism includes a retaining ring seat and a retaining ring. The outer wall of the retaining ring is conical, and the retaining ring seat has a conical inner wall that matches the retaining ring. The inner wall of the front end of the retaining ring is provided with a serrated anti-disengagement part that protrudes inward along the circumference. The anti-disengagement part is distributed in a continuous spiral along the circumference of the retaining ring. The retaining ring can be elastically deformed to open or retract and reset.

2. The dual-tube drill bit according to claim 1, characterized in that, A sealing assembly is also provided between the shaft and the sleeve. The sealing assembly includes a limiting member and a sealing ring. The sealing ring and the limiting member are both sleeved on the shaft, and the sealing ring abuts against the thrust bearing near the joint.

3. The dual-tube drill bit according to claim 2, characterized in that, The sleeve is provided with a nut and a round shaft nut near the front end of the shaft. The nut and the round shaft nut are connected by the nut and the round shaft nut. A pin is provided at the front end of the shaft, and the pin is threadedly connected to the round shaft nut and the shaft.

4. The dual-tube drill bit according to claim 3, characterized in that, The inner tube assembly further includes a main body and a transition part connected sequentially along the axial direction. One end of the transition part is connected to the main body, and the other end is detachably connected to the snap ring seat. The outer peripheral surface of the transition part is spaced apart from the inner wall of the outer tube assembly.

5. The dual-tube drill bit according to claim 1, characterized in that, The outer tube assembly includes an outer tube, the drill bit is threadedly connected to the outer tube, the drill bit is inlaid with a helically distributed cemented carbide, and a hole expander is sleeved on one end of the outer tube assembly near the drill bit, with a gasket sandwiched between the hole expander and the drill bit.

6. A water-powered drilling machine, characterized in that, include: The rotary power mechanism, the traveling mechanism, the guide rail, and the dual-tube drill bit as described in any one of claims 1-5, wherein the output end of the rotary power mechanism is connected to the joint of the dual-tube drill bit; the rotary power mechanism is mounted on the traveling mechanism, the traveling mechanism is mounted on the guide rail, and the traveling mechanism is used to drive the rotary power mechanism to reciprocate along the guide rail.

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