High-deflection screw drill

Abstract

The invention relates to a high deflecting screw drill applied to the field of drilling tools, which comprises a bypass valve assembly, the bottom of the bypass valve assembly is connected with a motor assembly, the bottom of the motor assembly is connected with a cardan shaft assembly, an outer-layer gear, an inner-layer gear, a middle-layer gear, a drill bit and a diagonal draw bar are matched, so that the working surface of the drill bit can be adjusted, and the working efficiency of the drill bit is improved. Under the cooperation of a wedge-shaped plug connector and a lead screw, self-adaptive adjustment of the drilling size can be achieved when the drill bit works, different drilling size requirements are met, and by means of movable connection of a diagonal draw bar and a strip-shaped groove, synchronous rotation of the driving shell and the drill bit is guaranteed when the drill bit moves outwards; and it is ensured that the drill bit treated by the adjusting unit can still normally conduct well drilling work.

Description

Technical Field

[0001] The invention relates to a screw drill tool, in particular to a high-deflection screw drill tool used in the field of drilling tools. Background Art

[0002] Screw drilling tools are a type of volumetric downhole power drill that uses drilling fluid as its motive force to convert liquid pressure energy into mechanical energy. They are mainly composed of a bypass valve, a screw motor (rotor and stator), a universal joint, bearings, and a drive shaft. High-inclination screw drilling tools are a type of drilling tool used for directional well construction. By shortening the distance between the bending point and the end face of the rotor input joint by a certain distance, such as 300-400mm, the distance between the drill bit and the bending point is reduced, thereby increasing the inclination rate.

[0003] The specification of Chinese invention patent CN118110416A discloses a high-inclination and efficient screw drill. The invention has good inclination and composite capabilities, so that the service life of the whole machine can be at least 2-3 times that of the existing one. In addition, the specification of Chinese patent CN213980634U discloses a high-inclination screw drill for medium-radius horizontal wells. During the composite drilling process, the middle stabilizer can reduce the vibration of the screw drill, making the wellbore smoother and reducing the full-angle change rate of the wellbore trajectory. The full-section operation can greatly reduce the sliding ratio, reduce the time and number of directional construction during the drilling process, and improve the drilling efficiency.

[0004] The drill bit in the existing high-inclination drilling tools is usually fixedly installed. During use, the drill bit will wear, which is not conducive to subsequent drilling. In addition, during the actual downhole drilling process, the inner diameter of the well is in a dynamically changing state. The fixedly installed drill bit is difficult to achieve the corresponding change in the drilling size, which limits the practicability of the high-inclination screw drilling tools. Summary of the invention

[0005] In view of the above-mentioned prior art, the technical problem to be solved by the present invention is how to switch the working surface of the drill bit when performing corresponding drilling processing to avoid the worn working surface from continuing to work, and at the same time adaptively adjust the drilling size of the drill bit to meet the changing drilling requirements.

[0006] In order to solve the above problems, the present invention provides a high-inclined screw drill, including a bypass valve assembly, the bottom of the bypass valve assembly is connected to a motor assembly, the bottom of the motor assembly is connected to a universal shaft assembly, the universal shaft assembly, the bottom of the universal shaft assembly is connected to a transmission shaft assembly, the transmission shaft assembly includes a drive housing and a transmission shaft body, the tail end of the transmission shaft body extends to the inside of the drive housing, and the tail end of the transmission shaft body is connected to the inner wall of the drive housing through a short rod, the bottom wall of the drive housing is installed with an inner gear, the outer side of the inner gear is surrounded by a plurality of middle gears meshingly connected, the outer side of each middle gear is meshingly connected with an outer gear, the inner side of the outer gear is penetrated by a plug rod, and a drill bit is installed at the bottom of the plug rod;

[0007] The surface of the drive shell near the bottom end is provided with a plurality of notches corresponding to the drill bits one by one, a dual drive motor with two drive ends is installed inside the drive shell, one of the drive ends of the dual drive motor is connected to the inner gear, an adjustment unit is installed inside the drive shell, and the surface of the drive shell is provided with strip grooves corresponding to the plurality of notches one by one and located above the notches, the top of the plug-in rod is connected to a diagonal tie rod through a hinge ball, and the tail end of the diagonal tie rod is movably connected to the strip groove through a hinge ball.

[0008] In the above-mentioned high-inclination screw drilling tool, the cooperation of the outer gear, the inner gear, the middle gear, the drill bit and the inclined tie rod can be used to adjust the working surface of the drill bit, and with the cooperation of the wedge connector and the lead screw, the drilling size can be adaptively adjusted when the drill bit is working to meet the requirements of different drilling sizes.

[0009] As a further improvement of the present application, the adjustment unit includes a lead screw located below the transmission shaft body, and the other driving end of the dual drive motor is connected to the lead screw, and a movable sleeve is threadedly sleeved on the surface of the lead screw, and a plurality of bridge rods with L-shaped cross-sections are fixedly installed on the surface of the movable sleeve, and the bottom end of the bridge rod is connected to a wedge-shaped connector via a self-resetting rotating shaft.

[0010] As a further improvement of the present application, the middle gear includes a fixed part and a movable part, the arc length of the movable part is smaller than that of the fixed part, and the surface of the fixed part close to the movable part is provided with two cylindrical grooves and a plug-in hole located between the two cylindrical grooves, a tension spring is connected to the inside of the cylindrical groove, and the tail end of the tension spring is connected to the surface of the movable part, and the surface of the movable part is connected to two plug-in blocks matching the plug-in holes.

[0011] As a further improvement of the present application, the cross-section of the wedge-shaped connector is a right-angled trapezoid, the vertical projection of the bottom end of the wedge-shaped connector is located at the gap between the fixed part and the movable part, and the wedge-shaped connector is located in the middle of the two connector blocks.

[0012] As a further improvement of the present application, the top surfaces of the middle gear and the outer gear are provided with annular grooves, the interiors of the two annular grooves are movably connected with a bridge member with an inverted U-shaped cross-section through a hinged ball, the top of the bridge member is connected with a reset spring, the top of the reset spring is fixedly connected with a disc, the top of the disc is rotatably connected with a sliding rod with an L-shaped cross-section, and the sliding rod slides through the interior of the bridge rod.

[0013] As a further improvement of the present application, in the initial state, there is a horizontal gap on the surface of the dual drive motor at one end of the sliding rod away from the outer gear, and the cross-sectional width of the movable part is greater than the maximum thickness of the wedge-shaped connector.

[0014] As a further improvement of the present application, the transmission shaft assembly also includes an outer shell, the bottom of the outer shell is rotatably connected to the top of the drive housing, and in an initial state, the vertical projection of the drill bit protruding from the drive housing is not less than half the volume of the drill bit.

[0015] As another improvement of the present application, the working method comprises the following steps:

[0016] S1. During drilling, the transmission shaft body rotates to drive the drive housing, and the drill bit rotates synchronously with the drive housing under the action of the inclined tie rod to perform drilling processing;

[0017] S2. After the working surface of the drill bit is worn, the meshing action of the dual drive motor, the inner gear, the middle gear and the outer gear is used to drive the working surface of the drill bit to adjust, and then continue the drilling work;

[0018] S3. When the drilling size needs to be adjusted, the screw is used to drive the wedge-shaped connector to descend, drive the movable part to move away from the inner gear, and drive the outer gear to move synchronously. At this time, the inclined rod moves down, and then the drilling work continues;

[0019] S4. On the basis of S3, when the drill bit working surface needs to be adjusted, the middle gear can be driven to rotate, and the meshing action between the movable part and the outer gear can be used to drive the adjustment of the drill bit working surface.

[0020] To sum up, by utilizing the cooperation of the outer gear, the inner gear, the middle gear, the drill bit and the inclined tie rod, the adjustment of the drill bit working surface can be achieved, and with the cooperation of the wedge-shaped connector and the lead screw, the adaptive adjustment of the drilling size when the drill bit is working can be achieved to meet the requirements of different drilling sizes, and by virtue of the movable connection between the inclined tie rod and the strip groove, when the drill bit moves outward, the synchronous rotation of the drive housing and the drill bit is guaranteed, ensuring that the drill bit processed by the adjustment unit can still perform drilling work normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the overall structure of the first implementation method of the present application;

[0022] Figure 2 This is a schematic diagram of the internal structure of the drive housing according to the first embodiment of the present application;

[0023] Figure 3 This is an installation diagram of the outer gear, inner gear and middle gear of the first embodiment of the present application;

[0024] Figure 4 This is a schematic diagram of the installation of the bridge member and the return spring of the first embodiment of the present application;

[0025] Figure 5 This is a state diagram of the drill bit when adjusting the working surface according to the first embodiment of the present application;

[0026] Figure 6 This is a schematic diagram of the installation of the tension spring and the plug-in block of the first embodiment of the present application;

[0027] Figure 7 This is a schematic diagram of the drill bit moving outward in the first embodiment of the present application;

[0028] Figure 8 This is a schematic diagram of the state of the inclined tie rod when the drill bit moves outward according to the first embodiment of the present application;

[0029] Fig. 9 This is a schematic diagram of the state of adjusting the working surface when the drill bit moves outward in the first embodiment of the present application;

[0030] Fig.10 This is a schematic diagram of the working steps of the second implementation method of this application.

[0031] Description of the numbers in the figure:

[0032] 1. Bypass valve assembly; 2. Motor assembly; 3. Universal joint assembly; 4. Drive shaft assembly; 41. Drive shaft body; 42. Drive housing; 5. Drill bit; 6. Diagonal tie rod; 7. Dual drive motor; 8. Outer gear; 9. Middle gear; 10. Inner gear; 11. Lead screw; 12. Bridge rod; 13. Wedge connector; 14. Return spring; 15. Bridge connector; 16. Tension spring; 17. Connector block. DETAILED DESCRIPTION

[0033] Two implementation modes of the present application are described in detail below with reference to the accompanying drawings.

[0034] The first implementation method:

[0035] Figure 1-3A high-inclined screw drilling tool is shown, comprising a bypass valve assembly 1, the bottom of the bypass valve assembly 1 is connected to a motor assembly 2, the bottom of the motor assembly 2 is connected to a universal shaft assembly 3, the universal shaft assembly 3, the bottom of the universal shaft assembly 3 is connected to a transmission shaft assembly 4, the transmission shaft assembly 4 comprises a drive housing 42 and a transmission shaft body 41, the tail end of the transmission shaft body 41 extends to the inside of the drive housing 42, and the tail end of the transmission shaft body 41 is connected to the inner wall of the drive housing 42 through a short rod, an inner gear 10 is installed on the bottom wall of the drive housing 42, a plurality of middle gears 9 are meshedly connected around the outer side of the inner gear 10, the outer side of each middle gear 9 is meshedly connected to an outer gear 8, a plug rod is installed through the inside of the outer gear 8, and a drill bit 5 is installed at the bottom of the plug rod;

[0036] The surface of the drive shell 42 near the bottom end is provided with a plurality of notches corresponding one to one with the drill bit 5, a dual drive motor 7 with two drive ends is installed inside the drive shell 42, one of the drive ends of the dual drive motor 7 is connected to the inner gear 10, an adjustment unit is installed inside the drive shell 42, and the surface of the drive shell 42 is provided with strip grooves corresponding one to one with the plurality of notches and located above the notches, the top of the plug-in rod is connected to the diagonal tie rod 6 through a hinge ball, and the tail end of the diagonal tie rod 6 is movably connected to the strip groove through a hinge ball.

[0037] The transmission shaft assembly 4 also includes a shell, the bottom of which is rotatably connected to the top of the drive housing 42 , and in an initial state, the portion of the drill bit 5 protruding from the drive housing 42 in the vertical direction is not less than half the volume of the drill bit 5 .

[0038] Specifically, when the screw drill is working, the bypass valve assembly 1, the motor assembly 2, the universal shaft assembly 3 and the transmission shaft assembly 4 are utilized (the working principles thereof are all prior art and will not be described in detail here).

[0039] When the transmission shaft body 41 rotates, the driving housing 42 is driven to rotate. Since the drill bit 5 is connected to the inclined rod 6 through the plug-in rod, and the inclined rod 6 is movably connected to the strip groove on the surface of the driving housing 42, when the driving housing 42 rotates, the inclined rod 6 can be driven to rotate synchronously, thereby driving the drill bit 5 to rotate synchronously with the driving housing 42, so that the three drill bits 5 can move synchronously to realize drilling processing.

[0040] After the initial working surface of the drill bit 5 is worn, the remaining part of the drill bit 5 (that is, the part of the drill bit 5 vertically projected in the driving housing 42 in the initial state) is in a normal usable state. At this time, one of the driving ends of the dual drive motor 7 is started to drive the inner gear 10 to rotate. Under the meshing action, the outer gear 8 can be indirectly driven to rotate synchronously (because the plug-in rod and the inclined rod 6 are movably connected, the inclined rod 6 is not affected when the outer gear 8 rotates), thereby driving the drill bit 5 to adjust the working surface (such as Figure 5shown).

[0041] Figure 3 It is shown that the adjustment unit includes a screw 11 located below the transmission shaft body 41, and the other driving end of the dual drive motor 7 is connected to the screw 11, and a movable sleeve is threadedly sleeved on the surface of the screw 11, and a plurality of bridge rods 12 with L-shaped cross-sections are fixedly installed on the surface of the movable sleeve, and the bottom end of the bridge rod 12 is connected to a wedge-shaped connector 13 through a self-resetting rotating shaft.

[0042] The cross section of the wedge-shaped connector 13 is a right-angled trapezoid. The projection of the bottom end of the wedge-shaped connector 13 in the vertical direction is located at the gap between the fixed part and the movable part, and the wedge-shaped connector 13 is located in the middle of the two connector blocks 17 .

[0043] When it is necessary to switch the working radius of the drill bit 5 (that is, the size of the drilling), it is necessary to adjust the position of the middle gear 9 first, that is, it is necessary to make the gap between the fixed part and the movable part vertically located below the wedge-shaped plug-in component 13 (an infrared transmitter and an infrared receiver can be installed on the surface of the fixed part and the wedge-shaped plug-in component 13, respectively, to assist in the adjustment, and the alignment method is not limited to one), and then start the other driving end of the dual-drive motor 7 to rotate the screw 11, thereby driving the bridge rod 12 to move downward, and then driving the wedge-shaped plug-in component 13 to descend. The fixed part and the movable part can be separated by means of the gradually widening wedge-shaped plug-in component 13, so that the movable part meshing with the outer gear 8 can drive the outer gear 8 to move away from the dual-drive motor 7, thereby indirectly driving the drill bit 5 to move outward and expanding the size of the well during drilling (such as Figure 7 shown).

[0044] As the drill bit 5 moves outward, the height position of the inclined tie rod 6 movably connected to it through the plug rod in the strip groove is gradually lowered, so that after the drill bit 5 moves outward, it can still maintain synchronous movement with the drive housing 42 by virtue of the active connection with the inclined tie rod 6, so as to perform the corresponding drilling operation normally (such as Figure 8 shown).

[0045] Figure 6 It is shown that the middle gear 9 includes a fixed part and a movable part, the arc length of the movable part is smaller than that of the fixed part, and the surface of the fixed part close to the movable part is provided with two cylindrical grooves and a plug-in hole located between the two cylindrical grooves, a tension spring 16 is connected to the inside of the cylindrical groove, and the tail end of the tension spring 16 is connected to the surface of the movable part, and the surface of the movable part is connected to two plug-in blocks 17 matching the plug-in holes.

[0046] Specifically, when the drill bit 5 moves outward, the tension spring 16 connected to the movable part will be stretched accordingly. When resetting is required, as the wedge-shaped connector 13 moves upward, the movable part will be reset under the action of the tension spring 16 and with the help of the plug-in block 17, the movable part and the fixed part will be plug-in constrained and integrated into one.

[0047] Figure 4 As shown, the top surfaces of the middle gear 9 and the outer gear 8 are both provided with annular grooves, and the interiors of the two annular grooves are movably connected with a bridge member 15 with an inverted U-shaped cross-section through a hinged ball, and the top of the bridge member 15 is connected with a reset spring 14, and the top of the reset spring 14 is fixedly connected with a disc, and the top of the disc is rotatably connected with a sliding rod with an L-shaped cross-section, and the sliding rod slides through the interior of the bridge rod 12.

[0048] Specifically, when the movable part is combined with the fixed part, the connecting function of the bridge member 15 can enable the movable part to drive the outer gear 8 to move synchronously when it is reset, thereby ensuring that the meshing action is stably maintained.

[0049] When the wedge-shaped connector 13 moves downward, the reset spring 14 is squeezed, and there is room for movement. Since the installation angle of the bridge rod 12 is fixed, the sliding rod and the reset spring 14 can constrain the bridge member 15, so that the ends of the bridge member 15 can move relative to each other in the two annular grooves but are not affected by the rotation of the outer gear 8 and the middle gear 9. Even if the fixed part and the movable part of the middle gear 9 are in a separated state, the annular groove on the surface of the movable part can still remain connected to the bridge member 15.

[0050] In the initial state, there is a horizontal gap on the surface of the dual drive motor 7 at one end of the sliding rod away from the outer gear 8, and the cross-sectional width of the movable portion is greater than the maximum thickness of the wedge-shaped connector 13.

[0051] Specifically, when the fixed portion and the movable portion are separated, the sliding rod moves synchronously through the fixed portion and does not affect the stability of the bridge member 15 .

[0052] When the working surface of the drill bit 5 needs to be adjusted when the fixed part and the movable part are separated, the rotation of the inner gear 10 can drive the fixed part to rotate slightly. At this time, due to the difference between the cross-sectional width of the movable part and the thickness of the wedge-shaped plug-in 13, the fixed part and the movable part are still in an overlapping state even in the maximum separation state. Therefore, when the fixed part rotates slightly, the movable part rotates synchronously, and the engagement of the movable part with the outer gear 8 can drive the drill bit 5 to achieve a small adjustment of the working surface (such as Fig. 9 shown).

[0053] In this process, since the wedge-shaped connector 13 is rotationally connected to the bridge rod 12, when the drill bit 5 adjusts the working surface, the wedge-shaped connector 13 can synchronously complete the corresponding deflection, and can be reset autonomously under the action of the automatic reset shaft after lifting and resetting.

[0054] The second implementation method:

[0055] Fig.10 The working method shown includes the following steps:

[0056] S1. During drilling, the transmission shaft body 41 rotates to drive the driving housing 42, and the drill bit 5 rotates synchronously with the driving housing 42 under the action of the inclined tie rod 6 to perform drilling processing;

[0057] S2. After the working surface of the drill bit 5 is worn, the meshing action of the dual drive motor 7, the inner gear 10, the middle gear 9 and the outer gear 8 is used to drive the working surface of the drill bit 5 to adjust, and then continue the drilling work;

[0058] S3. When the drilling size needs to be adjusted, the screw 11 is used to drive the wedge-shaped connector 13 to descend, drive the movable part to move away from the inner gear 10, and drive the outer gear 8 to move synchronously. At this time, the inclined rod 6 moves downward, and then the drilling work continues;

[0059] S4. On the basis of S3, when the working surface of the drill bit 5 needs to be adjusted, the middle gear 9 can be driven to rotate, and the meshing action between the movable part and the outer gear 8 can be used to drive the adjustment of the working surface of the drill bit 5.

[0060] In summary, by utilizing the cooperation of the outer gear 8, the inner gear 10, the middle gear 9, the drill bit 5 and the inclined tie rod 6, the adjustment of the working surface of the drill bit 5 can be achieved, and with the cooperation of the wedge-shaped connector 13 and the lead screw 11, the adaptive adjustment of the drilling size when the drill bit 5 is working can be achieved to meet the requirements of different drilling sizes, and by virtue of the movable connection between the inclined tie rod 6 and the strip groove, when the drill bit 5 moves outward, the synchronous rotation of the drive housing 42 and the drill bit 5 is guaranteed, ensuring that the drill bit 5 processed by the adjustment unit can still perform drilling work normally.

[0061] In view of current practical needs, the above-mentioned implementation mode adopted in this application is not limited to the scope of protection. Various changes made within the knowledge scope of technical personnel in this field without departing from the concept of this application still fall within the scope of protection of the present invention.

Claims

1. A high-inclination screw drilling tool, comprising a bypass valve assembly (1), wherein the bottom of the bypass valve assembly (1) is connected to a motor assembly (2), wherein the bottom of the motor assembly (2) is connected to a universal shaft assembly (3), wherein the universal shaft assembly (3), and the bottom of the universal shaft assembly (3) is connected to a transmission shaft assembly (4), characterized in that: The transmission shaft assembly (4) comprises a driving housing (42) and a transmission shaft body (41), the rear end of the transmission shaft body (41) extends to the interior of the driving housing (42), and the rear end of the transmission shaft body (41) is connected to the inner wall of the driving housing (42) through a short rod, an inner gear (10) is installed on the bottom wall of the driving housing (42), a plurality of middle gears (9) are meshedly connected around the outer side of the inner gear (10), each of the middle gears (9) is meshedly connected to the outer side of an outer gear (8), a plug-in rod is installed through the interior of the outer gear (8), and a drill bit (5) is installed at the bottom of the plug-in rod; The surface of the drive housing (42) near the bottom end is provided with a plurality of notches corresponding one to one with the drill bit (5); a dual drive motor (7) with two drive ends is installed inside the drive housing (42); one of the drive ends of the dual drive motor (7) is connected to the inner gear (10); an adjustment unit is installed inside the drive housing (42); the surface of the drive housing (42) is provided with strip grooves corresponding one to one with the plurality of notches and located above the notches; the top of the plug-in rod is connected to a diagonal tie rod (6) via a hinge ball, and the tail end of the diagonal tie rod (6) is movably connected to the strip groove via a hinge ball.

2. The high deflection screw drilling tool according to claim 1 is characterized in that: The adjustment unit comprises a lead screw (11) located below the transmission shaft body (41), and the other driving end of the dual drive motor (7) is connected to the lead screw (11), and a movable sleeve is threadedly sleeved on the surface of the lead screw (11), and a plurality of bridge rods (12) with L-shaped cross-sections are fixedly mounted on the surface of the movable sleeve, and the bottom end of the bridge rod (12) is connected to a wedge-shaped plug-in component (13) via a self-resetting rotating shaft.

3. The high deflection screw drilling tool according to claim 2, characterized in that: The middle gear (9) comprises a fixed part and a movable part, the arc length of the movable part is smaller than that of the fixed part, and the surface of the fixed part close to the movable part is provided with two cylindrical grooves and a plug-in hole located between the two cylindrical grooves, the inside of the cylindrical groove is connected with a tension spring (16), and the tail end of the tension spring (16) is connected to the surface of the movable part, and the surface of the movable part is connected with two plug-in blocks (17) matching the plug-in holes.

4. The high deflection screw drilling tool according to claim 3 is characterized in that: The cross section of the wedge-shaped plug-in component (13) is a right-angled trapezoid, the projection of the bottom end of the wedge-shaped plug-in component (13) in the vertical direction is located at the gap between the fixed part and the movable part, and the wedge-shaped plug-in component (13) is located in the middle of the two plug-in blocks (17).

5. The high deflection screw drilling tool according to claim 4 is characterized in that: The top surfaces of the middle gear (9) and the outer gear (8) are both provided with annular grooves, and the interiors of the two annular grooves are movably connected to a bridge member (15) with an inverted U-shaped cross section via a hinged ball, and the top of the bridge member (15) is connected to a reset spring (14), and the top of the reset spring (14) is fixedly connected to a disc, and the top of the disc is rotatably connected to a sliding rod with an L-shaped cross section, and the sliding rod slides through the interior of the bridge rod (12).

6. The high deflection screw drilling tool according to claim 5, characterized in that: In the initial state, a horizontal gap exists on the surface of the dual drive motor (7) at one end of the sliding rod away from the outer gear (8), and the cross-sectional width of the movable portion is greater than the maximum thickness of the wedge-shaped connector (13).

7. The high deflection screw drilling tool according to claim 6, characterized in that: The transmission shaft assembly (4) further comprises a housing, the bottom of which is rotatably connected to the top of the drive housing (42), and in an initial state, the portion of the drill bit (5) projected in the vertical direction protruding from the drive housing (42) is not less than half the volume of the drill bit (5).

8. The high deflection screw drilling tool according to claim 7, characterized in that: The working method includes the following steps: S1. During drilling, the transmission shaft body (41) rotates to drive the driving housing (42), and the drill bit (5) rotates synchronously with the driving housing (42) under the action of the inclined tie rod (6) to perform drilling processing; S2, after the working surface of the drill bit (5) is worn, the working surface of the drill bit (5) is adjusted by utilizing the meshing action of the dual drive motor (7), the inner gear (10), the middle gear (9) and the outer gear (8), and then the drilling operation is continued; S3. When the drilling size needs to be adjusted, the lead screw (11) is used to drive the wedge-shaped connector (13) to descend, driving the movable part to move away from the inner gear (10), driving the outer gear (8) to move synchronously, and at this time the inclined tie rod (6) moves downward, and then the drilling work continues; S4. On the basis of S3, when the working surface of the drill bit (5) needs to be adjusted, the middle gear (9) can be driven to rotate, and the meshing action between the movable part and the outer gear (8) can be used to drive the adjustment of the working surface of the drill bit (5).

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