A dual-power impact composite drill bit and method

Abstract

This invention discloses a dual-power impact composite drill bit and method, comprising a primary drill bit and a secondary drill bit mounted thereon. The primary drill bit's drive shaft is sequentially fitted with a first thrust cylindrical roller bearing, a rotor, a second thrust cylindrical roller bearing, an anvil, a hammer, a spring, a third thrust cylindrical roller bearing, and a lower connector. The first thrust cylindrical roller bearing is positioned between the primary and secondary drill bits. A fourth thrust cylindrical roller bearing is positioned between the rotor and the primary drill bit. An outer ring gear is screwed to the front of the rotor and meshes with an inner ring gear screwed into the secondary drill bit. The second thrust cylindrical roller bearing is positioned between the rotor and the anvil, which is screwed to the secondary drill bit's tube body. The third thrust cylindrical roller bearing is positioned between the secondary drill bit and the lower connector, which is screwed to the rear of the primary drill bit. This invention consists of two drill bits: the primary drill bit is powered by a drilling rig or a bottom-hole screw drill bit, while the secondary drill bit is powered by an internal rotor, achieving dual-power rock-breaking drilling and improving drilling efficiency.

Description

Technical Field

[0001] This invention belongs to the field of drill bit technology and relates to a dual-power impact composite drill bit and method. Background Technology

[0002] In tunnel drilling, efficient completion of drilling operations is crucial. To achieve efficient drilling, appropriate drilling techniques and equipment are required. Currently, rotary cutting drilling is generally used for softer and medium-hard formations, often employing PDC (Polymer Die Cut) bits for rock breaking. However, in hard formations, conventional PDC bits have limited penetration depth, resulting in low breaking efficiency. Impact rotary drilling is a method that uses an additional impact generator to apply impact force to the formation, achieving volumetric rock breaking in hard formations. This method often uses carbide ball-tooth bits, which can effectively improve drilling efficiency in hard formations. However, impact rotary drilling typically involves ball-tooth bits paired with hydraulic or pneumatic impactors; a single ball-tooth bit does not possess impact capability. Furthermore, existing PDC and ball-tooth bits are all single-stage full-range rock breaking bits; there are currently no patents, papers, or reports on dual-stage full-range rock breaking bits. Furthermore, whether it is conventional drilling or directional drilling, the rock-breaking power of the relevant drill bits mainly relies on equipment such as tunnel drilling rigs, bottom hole screw drills, and hydraulic impactors; individual drill bits do not yet have independent power capabilities. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a dual-power impact composite drill bit and method, solving problems such as the lack of dual-stage full-range rock breaking drill bit technology and the absence of autonomous power function in single drill bits.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A dual-power impact composite drill bit includes a primary drill bit and a secondary drill bit, with the secondary drill bit being fitted over the primary drill bit.

[0006] The first-stage drill bit includes an integral coaxial front end head and a drive shaft; the second-stage drill bit includes an integral coaxial tubular end head and a tubular body.

[0007] The drive shaft is fitted with, from front to back, a first thrust cylindrical roller bearing, a rotor, a second thrust cylindrical roller bearing, an anvil, a punch, a spring, a third thrust cylindrical roller bearing, and a lower connector.

[0008] The first thrust cylindrical roller bearing is positioned between the rear end face of the first stage drill bit and the first annular platform at the front of the second stage drill bit tube; a fourth thrust cylindrical roller bearing is positioned between the front end of the rotor and the rear end face of the first stage drill bit; an outer ring gear is screwed onto the front of the rotor and meshes with an inner ring gear screwed to the inner wall of the front of the second stage drill bit tube; the second thrust cylindrical roller bearing is positioned between the rear end of the rotor and the anvil, and the anvil is screwed to the inner wall of the second stage drill bit tube; the third thrust cylindrical roller bearing is positioned between the second annular platform at the rear of the second stage drill bit and the lower connector, and the lower connector is screwed to the rear of the drive shaft of the first stage drill bit.

[0009] The present invention also includes the following technical features:

[0010] Specifically, the front end face of the first-stage drill bit is provided with multiple sets of first PDC teeth and multiple sets of first ball teeth; the first PDC teeth and the first ball teeth are arranged alternately; the front end head is provided with multiple circumferentially distributed first water eyes, which connect the front end face and the rear end face of the front end head.

[0011] Specifically, the front end face of the tubular end of the secondary drill bit is provided with multiple sets of second PDC teeth and multiple sets of second ball teeth; the second PDC teeth and the second ball teeth are arranged alternately; the tubular end is provided with multiple circumferentially distributed second water eyes, and the inner wall of the front part of the tube is provided with multiple circumferentially distributed third water eyes, and the second water eyes and the third water eyes are connected in a one-to-one correspondence; the internal channel of the tube of the secondary drill bit is a first central through hole, and the second water eyes and the third water eyes connect the front end face of the secondary drill bit with the first central through hole.

[0012] Specifically, the rotor is a hollow structure with a central channel that is a second central through hole through which the drive shaft passes. The outer wall of the front part of the rotor is provided with a male thread section for connecting the outer ring gear, and the rear part is provided with an annular boss with the rear end face in contact with the second thrust cylindrical roller bearing. The outer wall of the middle part of the rotor is provided with multiple sets of axially evenly distributed helical blades. The helical blades connect the front and rear end faces of the rotor. With the front end face as the reference plane, the helical angle of the helical blades is 30° counterclockwise. The high-pressure liquid flows through the helical blades and drives the rotor to rotate.

[0013] Specifically, the anvil is an overall ring structure with a third central through hole, the inner diameter of which is slightly larger than the outer diameter of the drive shaft of the first-stage drill bit; the outer wall of the anvil is provided with male threads for threaded connection with the second-stage drill bit; the rear end face of the anvil is provided with multiple circumferentially distributed rising inclined surfaces, and a flow groove is provided between two rising inclined surfaces.

[0014] Specifically, the hammer has an overall annular structure with an outer diameter smaller than that of the anvil, allowing liquid to flow into the flow channel through the annular space between the hammer and the pipe body; the rear end of the hammer has an annular boss as a spring seat, with one end of the spring placed inside the annular boss; the central through hole of the hammer is a fourth central through hole, the inner diameter of which is slightly larger than the outer diameter of the drive shaft of the first-stage drill bit, ensuring that the hammer reciprocates along the drive shaft; the front end of the hammer has multiple circumferentially distributed impact teeth, the height of which is consistent with the lifting height of the rising inclined plane; the other end of the spring rests on the lower connector end face.

[0015] Specifically, the lower connector has a drive shaft connector at the front end, and the drive shaft connector has a female thread for connecting the male thread at the rear end of the drive shaft. The lower connector has multiple circumferentially distributed fan-shaped flow channels in the middle. The lower connector has a drill bit connector at the rear end, and its inner ring has a female thread for connecting the subsequent drill rod. The fan-shaped flow channels connect the drill rod flow channel and the pipe body.

[0016] Specifically, after the anvil is tightened to the secondary drill bit, the fourth thrust cylindrical roller bearing, the rotor, and the second thrust cylindrical roller bearing are axially limited and fixed on the drive shaft of the primary drill bit; after the lower connector is tightened to the drive shaft, the primary drill bit, the first thrust cylindrical roller bearing, the third thrust cylindrical roller bearing, and the secondary drill bit are axially limited and fixed; when the entire set of drill bits is installed, the impact teeth of the hammer contact the end face of the anvil, at which time the spring is in a compressed state, causing the hammer to press against the anvil.

[0017] A two-stage drilling method using a dual-power impact composite drill bit, the method being based on the aforementioned dual-power impact composite drill bit; comprising:

[0018] The dual-power composite drill bit is connected to the drill rod and water supply device through the lower connector and passes through the power head of the tunnel drilling rig. The water supply device is connected to the mud pump truck. When construction begins, the mud pump truck is turned on, and the high-pressure flushing fluid flows into the lower connector through the water supply device and drill rod. The fluid flows into the upper cavity of the rotor through the fan-shaped flow channel of the lower connector, the outer annulus of the hammer, and the flow groove of the anvil, driving the rotor to rotate in the forward direction. The rotation of the rotor causes the outer ring gear to rotate. The outer ring gear meshes with the inner ring gear connected to the secondary drill bit, causing the secondary drill bit to rotate.

[0019] The lower connector is mechanically connected to the drill pipe, so that the lower connector and the drilling rig rotate at the same speed. The lower connector is also mechanically connected to the drive shaft of the first-stage drill bit, so that the first-stage drill bit rotates at the same speed as the drilling rig.

[0020] The first-level and second-level drill bits mainly use the PDC teeth on the end face for rotary cutting and rock breaking.

[0021] An axial impact method for a dual-power impact composite drill bit, the method being based on the aforementioned dual-power impact composite drill bit; comprising:

[0022] The rotation of the secondary drill bit drives the anvil to rotate. The forward rotation of the anvil causes the impact teeth of the hammer to rise along the rising slope of the anvil. At this time, the spring is further compressed to store energy. After the hammer rises to the highest point of the anvil, it falls back and impacts the anvil once. Since the hammer is mounted on the drive shaft of the primary drill bit, it has the same rotation speed as the drilling machine. The secondary drill bit rotates 2 times and the primary drill bit rotates 1 time. Therefore, the secondary drill bit rotates 1 time relative to the primary drill bit. The hammer impacts the anvil. The primary and secondary drill bits mainly use the end face ball teeth to impact and rotate to break the rock.

[0023] Under the condition of constant pump pressure and pump volume, the rotor rotation speed is constant. By adjusting the rotation speed of the drilling rig, the impact frequency can be controlled. Increasing the rotation speed of the drilling rig reduces the impact frequency, which is suitable for soft and medium-hard formations. Decreasing the rotation speed of the drilling rig increases the impact frequency, which is suitable for drilling in hard formations.

[0024] Compared with the prior art, the present invention has the following technical effects:

[0025] The drill bit of this invention consists of two stages. The power of the first stage drill bit comes from the drilling rig or the bottom screw drill bit, while the power of the second stage drill bit comes from the built-in rotor turbine, realizing dual-power rock breaking drilling, which is beneficial to improving drilling efficiency.

[0026] The drill bit of this invention has a built-in impact mechanism, which can add axial impact force while realizing conventional rotary drilling. It is also equipped with PDC teeth and ball teeth arranged in combination on the end faces of the first-stage and second-stage drill bits, and can be used in soft, medium and hard formations and alternating formations.

[0027] The drill bit of this invention makes full use of the drilling rig power, screw power and flushing fluid pressure, realizing the effective use of energy during construction. The rotor structure is simple, the gear transmission mechanism is direct, and the impact mechanism adopts a spring energy storage structure with few vulnerable parts. The impact energy can be changed by replacing the energy storage spring.

[0028] The impact frequency of this invention is determined by the difference between the drilling rig speed or the screw drive shaft speed and the speed of the rotor driving the secondary drill bit. The rotor speed is determined by the pump pressure and flow rate of the mud pump truck. Under the condition of constant pump pressure and flow rate, the impact frequency can be increased or decreased by adjusting the drilling rig speed or the screw drive shaft speed. This process is simple to operate and provides rapid feedback. Attached Figure Description

[0029] Figure 1 This is a schematic diagram (I) of the dual-power impact composite drill bit of the present invention.

[0030] Figure 2 This is a schematic diagram (II) of the overall structure of the dual-power impact composite drill bit of the present invention.

[0031] Figure 3This is a front view of the first stage drill bit of the dual-power impact composite drill bit of the present invention.

[0032] Figure 4 This is a cross-sectional view (AA) of the first-stage drill bit of the dual-power impact composite drill bit of the present invention.

[0033] Figure 5 This is a front view of the secondary drill bit of the dual-power impact composite drill bit of the present invention.

[0034] Figure 6 This is a cross-sectional view of the secondary drill bit BB of the dual-power impact composite drill bit of the present invention.

[0035] Figure 7 This is a schematic diagram of the rotor blades of the dual-power impact composite drill bit of the present invention.

[0036] Figure 8 This is a schematic diagram of the anvil of the dual-power impact composite drill bit of the present invention.

[0037] Figure 9 This is a schematic diagram of the impact hammer of the dual-power impact composite drill bit of the present invention.

[0038] Figure 10 This is a front view of the lower connector of the dual-power impact composite drill bit of the present invention.

[0039] Figure 11 This is a CC cross-sectional view of the lower connector of the dual-power impact composite drill bit of the present invention.

[0040] The meanings of the labels in the diagram are as follows:

[0041] 1. First-stage drill bit, 2. Second-stage drill bit, 3. First-stage thrust cylindrical roller bearing, 4. Inner ring gear, 5. Rotor, 6. Second-stage thrust cylindrical roller bearing, 7. Anvil, 8. Hammer, 9. Spring, 10. Third-stage thrust cylindrical roller bearing, 11. Lower connector, 12. Fourth-stage thrust cylindrical roller bearing, 13. Outer ring gear;

[0042] 101. First PDC tooth, 102. First ball tooth, 103. First water inlet, 104. Drive shaft;

[0043] 201. Second PDC tooth, 202. Second ball tooth, 203. Second water inlet, 204. First annular platform, 205. First central through hole, 206. Third water inlet, 207. Second annular platform;

[0044] 501. Male thread section; 502. Helical blade; 503. Annular boss; 504. Second center through hole;

[0045] 701. Rising ramp; 702. Flow channel; 703. Third central through hole;

[0046] 801. Impact tooth; 802. Spring seat; 803. Fourth center through hole;

[0047] 1101. Fan-shaped flow channel; 1102. Drive shaft connector; 1103. Drill tool connector. Detailed Implementation

[0048] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0049] Example 1:

[0050] like Figures 1 to 11 As shown, this embodiment provides a dual-power impact composite drill bit, including a primary drill bit 1 and a secondary drill bit 2, with the secondary drill bit 2 sleeved outside the primary drill bit 1; the primary drill bit 1 includes an integral coaxial front end head and a drive shaft 104; the secondary drill bit 2 includes an integral coaxial tubular end head and a tubular body.

[0051] The drive shaft 104 is fitted with, from front to back, a first thrust cylindrical roller bearing 3, a rotor 5, a second thrust cylindrical roller bearing 6, an anvil 7, a punch 8, a spring 9, a third thrust cylindrical roller bearing 10, and a lower connector 11.

[0052] The first thrust cylindrical roller bearing 3 is positioned between the rear end face of the front end of the first-stage drill bit 1 and the first annular platform 204 at the front of the tube body of the second-stage drill bit 2. A fourth thrust cylindrical roller bearing 12 is positioned between the front end of the rotor 5 and the rear end face of the front end of the first-stage drill bit 1, allowing the rotor 5 to rotate freely around the first-stage drill bit 1. An outer ring gear 13 is screwed onto the front of the rotor 5 and meshes with an inner ring gear 4 screwed onto the inner wall of the front of the tube body of the second-stage drill bit 2; both gears have the same number of teeth. The second thrust cylindrical roller bearing 6 is positioned between the rear end of the rotor 5 and the anvil 7, which is screwed onto the inner wall of the tube body of the second-stage drill bit 2. The third thrust cylindrical roller bearing 10 is positioned between the second annular platform 207 at the rear of the second-stage drill bit 2 and the lower connector 11, which is screwed onto the rear of the drive shaft 104 of the first-stage drill bit 1. The diameter of the front end is larger than the diameter of the drive shaft 104, and there is an annular space between the drive shaft 104 and the tube body.

[0053] The front end face of the first-stage drill bit 1 is provided with multiple sets of first PDC teeth 101 and multiple sets of first ball teeth 102; the first PDC teeth 101 and the first ball teeth 102 are arranged alternately; the front end face is provided with multiple axial first water eyes 103, such as 6 circumferentially distributed, which connect the front end face and the rear end face of the front end face and are used to cool the first PDC teeth 101 and the first ball teeth 102.

[0054] The front end face of the tubular end of the secondary drill bit 2 is provided with multiple sets of second PDC teeth 201 and multiple sets of second ball teeth 202; the second PDC teeth 201 and the second ball teeth 202 are arranged alternately; the tubular end is provided with multiple axial second water eyes 203 evenly distributed in six circles, and the inner wall of the front part of the tube is provided with multiple first central through holes 206 evenly distributed in six circles, and the second water eyes 203 and the first central through holes 206 are connected one-to-one; the internal channel of the tube of the secondary drill bit 2 is the first central through hole 205, and the second water eyes 203 and the first central through hole 206 connect the front end face of the secondary drill bit 2 and the first central through hole 205; specifically, the left end of the first central through hole 205 is provided with a female thread for connecting the inner ring gear 4, and the right end of the first central through hole 205 is provided with a female thread for connecting the anvil 7.

[0055] The rotor 5 has a hollow structure with a central channel, which is a second central through hole 504, through which the drive shaft 104 passes. The front outer wall of the rotor 5 is provided with a male thread section 501 for connecting the outer ring gear 13, and the rear part is provided with an annular boss 503, the rear end face of which contacts the second thrust cylindrical roller bearing 6. The middle outer wall of the rotor 5 is provided with multiple sets, such as three sets, of axially evenly distributed helical blades 502. The helical blades 502 connect the front and rear end faces of the rotor 5. With the front end face as the reference plane, the helical angle of the helical blades 502 is 30° counterclockwise. After the high-pressure liquid flows through the helical blades 502, it drives the rotor 5 to rotate clockwise.

[0056] The anvil 7 has an overall ring structure and a central through hole, which is a third central through hole 703. The inner diameter of the third central through hole 703 is slightly larger than the outer diameter of the drive shaft 104 of the first-stage drill bit 1. The outer wall of the anvil 7 is provided with male threads for threaded connection with the second-stage drill bit 2. The rear end face of the anvil 7 is provided with multiple rising inclined surfaces 701, such as four circumferentially distributed surfaces, and a flow groove 702 is provided between two rising inclined surfaces 701.

[0057] The hammer 8 has an overall annular structure with an outer diameter smaller than that of the anvil 7, allowing liquid to flow into the flow channel 702 through the annular space between the hammer 8 and the tube body. The rear end of the hammer 8 has an annular boss as a spring seat 802, and one end of the spring 9 is placed inside the annular boss. The through hole in the middle of the hammer 8 is the fourth central through hole 803, and the inner diameter of the fourth central through hole 803 is slightly larger than the outer diameter of the drive shaft 104 of the first-stage drill bit 1, ensuring that the hammer 8 reciprocates along the drive shaft 104. The front end of the hammer 8 has multiple impact teeth 801, such as four circumferentially distributed impact teeth, and the height of the impact teeth 801 is consistent with the lifting height of the rising inclined plane 701. The other end of the spring 9 rests on the end face of the lower connector.

[0058] The lower connector has a drive shaft connector 1102 at the front end, and the drive shaft connector 1102 has a female thread for connecting the male thread at the rear end of the drive shaft 104. The lower connector has multiple fan-shaped flow channels 1101 evenly distributed around the circumference, such as five. The lower connector has a drill bit connector 1103 at the rear end, and its inner ring has a female thread for connecting the subsequent drill rod. The fan-shaped flow channels 1101 connect the drill rod flow channel and the first central through hole 205 of the pipe body.

[0059] After the anvil 7 is tightened with the secondary drill bit 2, the fourth thrust cylindrical roller bearing 12, rotor 5, and second thrust cylindrical roller bearing 6 are axially limited and fixed on the drive shaft 104 of the primary drill bit 1. After the lower connector is tightened with the drive shaft 104, the primary drill bit 1, first thrust cylindrical roller bearing 3, third thrust cylindrical roller bearing 10, and secondary drill bit 2 are axially limited and fixed. When the entire set of drill bits is installed, the impact teeth 801 of the punch 8 contact the end face of the anvil 7. At this time, the spring 9 is in a certain compressed state, so that the punch 8 presses against the anvil 7.

[0060] Example 2:

[0061] This embodiment provides a two-stage drilling method using a dual-power impact composite drill bit, based on the dual-power impact composite drill bit of Embodiment 1; including:

[0062] The dual-power composite drill bit is connected to the drill rod, water supply device, etc. through the lower connector and passes through the power head of the tunnel drilling rig. The water supply device is connected to the mud pump truck. When construction begins, the mud pump truck is turned on, and the high-pressure flushing fluid flows into the lower connector through the water supply device and drill rod. The fluid flows into the upper cavity of the rotor through the fan-shaped flow channel of the lower connector, the outer annulus of the hammer, and the flow groove of the anvil, driving the rotor to rotate in the forward direction. The pump pressure is 3MPa, the pump flow rate is 300L / min, and the rotor rotation speed is about 100r / min. The rotation of the rotor causes the outer ring gear to rotate. The outer ring gear meshes with the inner ring gear connected to the secondary drill bit, causing the secondary drill bit to rotate.

[0063] The lower connector is mechanically connected to the drill pipe, so that the lower connector and the drilling rig rotate at the same speed. The lower connector is mechanically connected to the drive shaft of the first-stage drill bit, so that the first-stage drill bit rotates at the speed of the drilling rig, and the rotation speed of the drilling rig is controlled to be about 50 r / min.

[0064] The first-level and second-level drill bits mainly use the PDC teeth on the end face for rotary cutting and rock breaking.

[0065] This embodiment also provides an axial impact method for a dual-power impact composite drill bit, which is based on the dual-power impact composite drill bit of Embodiment 1; including:

[0066] The rotation of the secondary drill bit drives the anvil to rotate (100 r / min). The forward rotation of the anvil causes the impact teeth of the hammer to rise along the rising slope of the anvil. At this time, the spring is further compressed to store energy. After the hammer rises to the highest point of the anvil, it falls back and impacts the anvil once. Since the hammer is mounted on the drive shaft of the primary drill bit, it has the same rotation speed as the drilling rig (50 r / min). The secondary drill bit rotates 2 times and the primary drill bit rotates 1 time. Therefore, the secondary drill bit rotates 1 time relative to the primary drill bit. The hammer impacts the anvil 4 times, with 200 impacts per minute. The primary and secondary drill bits mainly use the end face ball teeth to impact and rotate to break the rock.

[0067] Under the condition of constant pump pressure and pump volume, the rotor rotation speed is constant. By adjusting the rotation speed of the drilling rig, the impact frequency can be controlled. Appropriately increasing the rotation speed of the drilling rig will reduce the impact frequency, which is suitable for soft and medium-hard strata. Appropriately decreasing the rotation speed of the drilling rig will increase the impact frequency, which is suitable for drilling in hard strata.

[0068] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0069] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0070] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A dual-power impact composite drill bit, characterized in that, It includes a primary drill bit (1) and a secondary drill bit (2), with the secondary drill bit (2) fitted over the primary drill bit (1); The first-stage drill bit (1) includes an integral coaxial front end head and a drive shaft (104); the second-stage drill bit (2) includes an integral coaxial tubular end head and a tubular body. The drive shaft (104) is fitted with, from front to back, a first thrust cylindrical roller bearing (3), a rotor (5), a second thrust cylindrical roller bearing (6), an anvil (7), a punch (8), a spring (9), a third thrust cylindrical roller bearing (10), and a lower connector (11). The first thrust cylindrical roller bearing (3) is placed between the rear end face of the front end of the first-stage drill bit (1) and the first annular platform (204) at the front of the tube of the second-stage drill bit (2); a fourth thrust cylindrical roller bearing (12) is provided between the front end of the rotor (5) and the rear end face of the front end of the first-stage drill bit (1); a screwed outer ring gear (13) is fitted on the front of the rotor (5) and meshes with an inner ring gear (4) screwed to the inner wall at the front of the tube of the second-stage drill bit (2); the second thrust cylindrical roller bearing (6) is placed between the rear end of the rotor (5) and the anvil (7), and the anvil (7) is screwed to the inner wall of the tube of the second-stage drill bit (2); the third thrust cylindrical roller bearing (10) is placed between the second annular platform (207) at the rear of the second-stage drill bit (2) and the lower connector (11), and the lower connector (11) is screwed to the rear of the drive shaft (104) of the first-stage drill bit (1); The anvil (7) is an annular structure with a central through hole that is a third central through hole (703). The inner diameter of the third central through hole (703) is slightly larger than the outer diameter of the drive shaft (104) of the first-stage drill bit (1). The outer wall of the anvil (7) is provided with male threads to be threadedly connected to the second-stage drill bit (2). The rear end face of the anvil (7) is provided with multiple circumferentially distributed rising inclined surfaces (701), and a flow groove (702) is provided between two rising inclined surfaces (701).

2. The dual-power impact composite drill bit as described in claim 1, characterized in that, The front end face of the first-stage drill bit (1) is provided with multiple sets of first PDC teeth (101) and multiple sets of first ball teeth (102); the first PDC teeth (101) and the first ball teeth (102) are arranged alternately; the front end face is provided with multiple circumferentially distributed first water eyes (103), and the first water eyes (103) connect the front end face and the rear end face of the front end face.

3. The dual-power impact composite drill bit as described in claim 1, characterized in that, The front end face of the tubular end of the secondary drill bit (2) is provided with multiple sets of second PDC teeth (201) and multiple sets of second ball teeth (202); the second PDC teeth (201) and the second ball teeth (202) are arranged alternately; the tubular end is provided with multiple circumferentially distributed second water eyes (203), and the inner wall of the front part of the tube is provided with multiple circumferentially distributed third water eyes (206), and the second water eyes (203) and the third water eyes (206) are connected one-to-one; the tube body channel of the secondary drill bit (2) is a first central through hole (205), and the second water eyes (203) and the third water eyes (206) connect the front end face of the secondary drill bit (2) and the first central through hole (205).

4. The dual-power impact composite drill bit as described in claim 1, characterized in that, The rotor (5) is a hollow structure with a central channel being a second central through hole (504), through which the drive shaft (104) passes. The front outer wall of the rotor (5) is provided with a male thread section (501) for connecting the outer ring gear (13), and the rear part is provided with an annular boss (503) and the rear end face is in contact with the second thrust cylindrical roller bearing (6). The middle outer wall of the rotor (5) is provided with multiple sets of axially evenly distributed spiral blades (502). The spiral blades (502) connect the front and rear end faces of the rotor (5). With the front end face as the reference plane, the spiral angle of the spiral blades (502) is 30° counterclockwise. After the high-pressure liquid flows through the spiral blades (502), it drives the rotor (5) to rotate.

5. The dual-power impact composite drill bit as described in claim 1, characterized in that, The hammer (8) is an annular structure with an outer diameter smaller than that of the anvil (7), allowing liquid to flow into the flow channel (702) through the annular space between the hammer (8) and the pipe body. The rear end of the hammer (8) is provided with an annular boss as a spring seat (802), and one end of the spring (9) is placed inside the annular boss. The through hole in the middle of the hammer (8) is a fourth central through hole (803), and the inner diameter of the fourth central through hole (803) is slightly larger than the outer diameter of the drive shaft (104) of the first-stage drill bit (1), ensuring that the hammer (8) reciprocates along the drive shaft (104). The front end of the hammer (8) is provided with multiple circumferentially distributed impact teeth (801), and the height of the impact teeth (801) is consistent with the lifting height of the rising inclined plane (701). The other end of the spring (9) is placed on the end face of the lower connector (11).

6. The dual-power impact composite drill bit as described in claim 1, characterized in that, The lower connector (11) has a drive shaft connector (1102) at its front end. The drive shaft connector (1102) has a female thread for connecting the male thread at the rear end of the drive shaft (104). The lower connector (11) has multiple circumferentially distributed fan-shaped flow channels (1101) in the middle. The lower connector (11) has a drill bit connector (1103) at its rear end. Its inner ring has a female thread for connecting the subsequent drill rod. The fan-shaped flow channels (1101) connect the drill rod flow channel and the tube body.

7. The dual-power impact composite drill bit as described in claim 1, characterized in that, After the anvil (7) is tightened with the secondary drill bit (2), the fourth thrust cylindrical roller bearing (12), the rotor (5), and the second thrust cylindrical roller bearing (6) are axially limited and fixed on the drive shaft (104) of the primary drill bit (1); after the lower connector (11) is tightened with the drive shaft (104), the primary drill bit (1), the first thrust cylindrical roller bearing (3), the third thrust cylindrical roller bearing (10) and the secondary drill bit (2) are axially limited and fixed; when the entire set of drill bits is installed, the impact teeth (801) of the hammer (8) contact the end face of the anvil (7), at which time the spring (9) is in a compressed state, so that the hammer (8) presses against the anvil (7).

8. A two-stage drilling method using a dual-power impact composite drill bit, characterized in that, This method is based on the dual-power impact composite drill bit according to any one of claims 2 to 7; comprising: The dual-power composite drill bit is connected to the drill rod and water supply device through the lower connector and passes through the power head of the tunnel drilling rig. The water supply device is connected to the mud pump truck. When construction begins, the mud pump truck is turned on, and the high-pressure flushing fluid flows into the lower connector through the water supply device and drill rod. The fluid flows into the upper cavity of the rotor through the fan-shaped flow channel of the lower connector, the outer annulus of the hammer, and the flow groove of the anvil, driving the rotor to rotate in the forward direction. The rotation of the rotor causes the outer ring gear to rotate. The outer ring gear meshes with the inner ring gear connected to the secondary drill bit, causing the secondary drill bit to rotate. The lower connector is mechanically connected to the drill pipe, so that the lower connector and the drilling rig rotate at the same speed. The lower connector is also mechanically connected to the drive shaft of the first-stage drill bit, so that the first-stage drill bit rotates at the same speed as the drilling rig. The first-level and second-level drill bits mainly use the PDC teeth on the end face for rotary cutting and rock breaking.

9. An axial impact method for a dual-power impact composite drill bit, characterized in that, This method is based on the dual-power impact composite drill bit according to any one of claims 2 to 7; comprising: The rotation of the secondary drill bit drives the anvil to rotate. The forward rotation of the anvil causes the impact teeth of the hammer to rise along the rising slope of the anvil. At this time, the spring is further compressed to store energy. After the hammer rises to the highest point of the anvil, it falls back and impacts the anvil once. Since the hammer is mounted on the drive shaft of the primary drill bit, it has the same rotation speed as the drilling rig. The secondary drill bit rotates 2 times and the primary drill bit rotates 1 time. Therefore, the secondary drill bit rotates 1 time relative to the primary drill bit. The hammer impacts the anvil. The primary and secondary drill bits mainly use the end face ball teeth to impact and rotate to break the rock. Under the condition of constant pump pressure and pump volume, the rotor rotation speed is constant. By adjusting the rotation speed of the drilling rig, the impact frequency can be controlled. Increasing the rotation speed of the drilling rig reduces the impact frequency, which is suitable for soft and medium-hard formations. Decreasing the rotation speed of the drilling rig increases the impact frequency, which is suitable for drilling in hard formations.

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