A soft-start screw drill adapted for a rotary guide tool

Abstract

The present invention relates to the technical field of screw drill tools, and specifically to a soft-start screw drill tool adapted for a rotary guide tool, comprising a housing, and a rotor, a universal joint, and a transmission shaft sequentially installed in the housing, wherein the universal joint comprises an upper shaft body and a lower shaft body, wherein the upper end of the upper shaft body is connected to the lower end of the rotor via a rotor joint, and the lower end of the lower shaft body is connected to the upper end of the transmission shaft via a water cap joint, a buffer hole is provided at the upper end of the lower shaft body, and a buffer rod is provided at the lower end of the upper shaft body, a first involute bevel tooth is provided on the hole wall surrounding the buffer hole, and a second involute bevel tooth is provided on the outer wall surrounding the buffer rod, the buffer rod is installed in the buffer hole, and the first involute bevel tooth is meshed with the second involute bevel tooth, an elastic member is installed at the bottom of the buffer hole, and the upper end of the elastic member is connected to the lower end of the buffer rod by contact. The invention solves the problem that the screw motor instantly generates high speed and torque when starting, which causes a certain impact on the rotary guide tool, affecting its performance and life.

Description

Technical Field

[0001] The invention relates to the technical field of screw drill tools, and in particular to a soft-start screw drill tool adapted to a rotary guide tool. Background Art

[0002] my country's oil and gas exploration and development sector is expanding from conventional resources to unconventional resources such as low-permeability, deep and ultra-deep formations, deepwater offshore, and shale oil and gas. Rotary steerable drilling technology is a mature wellbore trajectory control technology, currently used both domestically and internationally. The majority of directional wells worldwide utilize rotary steerable systems, offering advantages such as low friction torque, excellent wellbore quality, and highly automated trajectory control. This has led to their successful application in specialized wells such as extended-reach, ultra-deep, and horizontal wells. Because rotary steerable systems are driven by the top drive (TDD), they are constrained by factors such as TDD torque and speed output, tool stick-slip vibration, and casing wear. This results in lower ROPs when drilling in speed-sensitive formations. To achieve improved efficiency, the use of a dedicated rotary steerable screw is essential. However, upon startup, the screw motor generates a transient high speed and torque, which can impact the rotary steerable tool, impacting its performance and lifespan. Summary of the Invention

[0003] The purpose of the present invention is to provide a soft-start screw drill adapted for a rotary guide tool, so as to solve the problem that the screw motor instantly generates high speed and torque when starting, causing a certain impact on the rotary guide tool, thereby affecting its performance and life.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] A soft-start screw drill adapted for a rotary guide tool comprises a shell, and a rotor, a universal shaft and a transmission shaft sequentially installed in the shell, the lower end of the transmission shaft is connected to the rotary guide tool below the shell, the universal shaft comprises an upper shaft body and a lower shaft body, the upper end of the upper shaft body is connected to the lower end of the rotor through a rotor joint, the lower end of the lower shaft body is connected to the upper end of the transmission shaft through a water cap joint, a buffer hole is provided at the upper end of the lower shaft body, a buffer rod is provided at the lower end of the lower shaft body, a first involute bevel tooth is provided on the hole wall surrounding the buffer hole, a second involute bevel tooth is provided on the outer wall surrounding the buffer rod, the buffer rod is installed in the buffer hole, and the first involute bevel tooth is meshed with the second involute bevel tooth, an elastic part is installed at the bottom of the buffer hole, and the upper end of the elastic part is connected to the lower end of the buffer rod in contact with each other.

[0006] A further technical solution is that a pressure relief hole connected to the lower end of the buffer rod is vertically arranged in the buffer rod, a rubber ball is slidably arranged in the pressure relief hole, and the rubber ball is sealingly fitted and slidably connected to the hole wall of the pressure relief hole.

[0007] A further technical solution is that the buffer hole is filled with hydraulic oil between the bottom of the buffer hole and the lower end of the buffer rod; a throttle valve is installed at the lower end of the pressure relief hole, the upper end of the pressure relief hole is connected to the upper end of the upper shaft body, and the upper end of the upper shaft body is installed with a ball head support for sealing the upper end of the pressure relief hole; the elastic part is a disc spring.

[0008] A further technical solution is that a mounting groove is recessed on the wall of the buffer hole, and an anti-drop clip is slidably arranged in the mounting groove. The upper side of the anti-drop clip is inclined downward to one end toward the buffer rod to form a first inclined surface. The anti-drop clip is connected to the bottom of the mounting groove through a spring. A limiting groove is recessed around the outer wall of the buffer rod. The upper groove wall of the limiting groove is inclined upward from the bottom of the groove to the groove mouth to form a second inclined surface. The end of the anti-drop clip is clamped in the limiting groove before the upper shaft body rotates.

[0009] A further technical solution is that a sealing ring is installed on the wall of the buffer hole near the hole mouth, and the inner wall of the sealing ring is sealed and fitted with the outer wall of the buffer rod; a first guide ring is provided on the wall of the buffer hole above and below the sealing ring, and the inner wall of the first guide ring is slidingly fitted with the inner wall of the buffer rod; a second guide ring is provided on the outer wall of the buffer rod below the second involute bevel tooth, and the outer wall of the second guide ring is slidingly fitted with the wall of the buffer hole; the wall of the buffer hole is provided with a connecting groove connected to the outer wall of the lower shaft body.

[0010] A further technical solution is that the upper end of the rotor joint is connected to the lower end of the rotor, and a connecting groove is provided at the lower end. The inner wall of the connecting groove is vertically provided with a first drive groove connected to the lower side of the rotor joint. The upper end of the upper shaft body is inserted into the connecting groove, and the outer wall of the upper shaft body is provided with a drive block matching the first drive groove. The drive block is embedded in the first drive groove, and a gap is left between the drive block and the first drive groove. The groove wall of the first drive groove is recessed with a first transmission groove, and the side wall of the drive block is provided with a second transmission groove corresponding to the position of the first transmission groove. The first transmission groove and the second transmission groove cooperate to form an active cavity, and an arc roller is movably provided in the active cavity; a connecting ring groove is provided on the outer wall surrounding the upper shaft body below the drive block, and the notch of the connecting groove is connected to a limiting ring, and the limiting ring is movably provided in the connecting ring groove.

[0011] A further technical solution is that the limiting ring is installed on the notch of the connecting groove through the fixing ring, the inner wall of the upper end of the fixing ring is recessed to form a threaded ring groove, the upper groove wall of the threaded ring groove is connected to the upper end of the fixing ring, the groove bottom of the threaded ring groove is provided with a first thread, the outer wall of the lower end of the rotor joint is provided with a second thread, the first thread and the second thread are threadedly matched and connected, and the outer wall of the limiting ring is provided with a clamping ring, which is clamped between the lower end of the rotor joint and the lower groove wall of the threaded ring groove.

[0012] A further technical solution is that a flexible sealing sheet is provided between the fixing ring and the outer wall of the upper shaft body, the lower side of the flexible sealing sheet is sealedly connected to the outer wall of the upper shaft body, and the upper side is sealedly connected to the inner wall of the fixing ring.

[0013] A further technical solution is that a TC bearing is installed on the outer wall of the transmission shaft, the surface of the TC bearing is provided with a wear-resistant layer, and the surface of the wear-resistant layer is provided with spiral grooves.

[0014] Compared with the prior art, the present invention has at least one of the following beneficial effects: 1. When starting, the rotor drives the upper shaft to rotate, and the upper shaft gradually moves toward the bottom of the buffer groove through the cooperation of the first involute bevel gear and the second involute bevel gear, and gradually compresses the elastic member, and in the process of compressing the elastic member, it gradually drives the lower shaft to rotate. When the end faces of the upper shaft and the lower shaft are in contact, the first involute bevel gear and the second involute bevel gear cannot move relative to each other. At this time, the upper shaft and the lower shaft rotate at the same speed, and in the process of the upper shaft moving toward the bottom of the lower shaft groove through the involute bevel gear, the hydraulic oil between the upper shaft and the lower shaft will flow into the pressure relief hole of the upper shaft through the throttle valve, and then the pressure balance at both ends is adjusted by the rubber ball. From the beginning of the rotation of the upper shaft to the process of the lower shaft and the upper shaft rotating at the same speed, the adverse effect of the impact torque on the rotary guide tool can be reduced; 2. When stopping, the elastic potential energy accumulated after the elastic member is compressed can push the buffer rod to move upward, so that it can continue to play a buffering role when starting next time. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of a soft-start screw drill adapted for a rotary guide tool according to the present invention.

[0016] Figure 2 for Figure 1 A partial enlarged schematic diagram of the area marked A.

[0017] Figure 3 for Figure 1 A partial enlarged schematic diagram of the area marked B in the middle.

[0018] Figure 4 The horizontal cross-sectional diagram of the connection between the upper end of the upper shaft body and the arc roller of a soft-start screw drill adapted to a rotary guide tool of the present invention is shown.

[0019] Figure 5 This is a schematic diagram of a TC bearing for a soft-start screw drill adapted for a rotary guide tool according to the present invention.

[0020] Icon: 1-housing, 2-rotor, 3-universal shaft, 5-upper shaft, 6-lower shaft, 7-rotor joint, 8-water cap joint, 9-buffer hole, 10-buffer rod, 11-first involute helical tooth, 12-second involute helical tooth, 13-pressure relief hole, 14-rubber ball, 15-throttle valve, 16-ball head support, 17-disc spring, 18-mounting slot, 19-anti-drop clip, 20-first inclined surface, 21-spring, 22-limiting slot, 23-second inclined surface, 2 4-sealing ring, 25-first guide ring, 26-second guide ring, 27-connecting groove, 28-cambered roller, 29-driving block, 30-connecting ring groove, 31-limiting ring, 32-fixing ring, 33-threaded ring groove, 34-retaining ring, 35-flexible sealing sheet, 36-transmission shaft, 37-TC bearing, 38-wear-resistant layer, 39-spiral groove, 40-first drive groove, 41-first transmission groove, 42-second transmission groove, 43-communication groove, 44-oil plug. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] Figures 1 to 5 Shown is an embodiment of the present invention,

[0023] Example:

[0024] A soft-start screw drilling tool adapted for a rotary guide tool comprises a shell 1, and a rotor 2, a universal shaft 3 and a transmission shaft 36 installed in sequence in the shell 1. The lower end of the transmission shaft 36 is connected to the rotary guide tool below the shell 1. The universal shaft 3 comprises an upper shaft body 5 and a lower shaft body 6. The upper end of the upper shaft body 5 is connected to the lower end of the rotor 2 through a rotor joint 7, and the lower end of the lower shaft body 6 is connected to the upper end of the transmission shaft 36 through a water cap joint 8. A buffer hole 9 is provided at the upper end of the lower shaft body 6, and a buffer rod 10 is provided at the lower end of the lower shaft body 6. A first involute bevel tooth 11 is provided on the hole wall surrounding the buffer hole 9, and a second involute bevel tooth 12 is provided on the outer wall surrounding the buffer rod 10. The buffer rod 10 is installed in the buffer hole 9, and the first involute bevel tooth 11 is meshed with the second involute bevel tooth 12. An elastic member is installed at the bottom of the buffer hole 9, and the upper end of the elastic member is connected to the lower end of the buffer rod 10 by top contact. During startup, the rotor 2 drives the upper shaft 5 to rotate. The upper shaft 5 gradually moves toward the bottom of the buffer hole 9 through the cooperation of the first involute bevel teeth 11 and the second involute bevel teeth 12, and gradually compresses the elastic member. In the process of compressing the elastic member, the lower shaft 6 is gradually driven to rotate. When the end faces of the upper shaft 5 and the lower shaft 6 are in contact, the first involute bevel teeth 11 and the second involute bevel teeth 12 cannot move relative to each other. At this time, the upper shaft 5 and the lower shaft 6 rotate at the same speed. In the process of the upper shaft 5 moving toward the bottom of the groove of the lower shaft 6 through the involute bevel teeth, the hydraulic oil between the upper shaft 5 and the lower shaft 6 flows into the pressure relief hole 13 of the upper shaft 5 through the throttle valve 15, and then the pressure balance at both ends is adjusted by the rubber ball 14. From the beginning of the rotation of the upper shaft 5 to the synchronization of the rotation of the lower shaft 6 and the upper shaft 5, the adverse effects of the impact torque on the rotary guide tool can be reduced. When the vehicle stops, the elastic potential energy accumulated after the elastic member is compressed can push the buffer rod 10 to move upward, so that it can continue to play a buffering role when starting next time.

[0025] A pressure relief hole 13 is vertically provided in the buffer rod 10 and is connected to the lower end of the buffer rod 10. A rubber ball 14 is slidably provided in the pressure relief hole 13. The rubber ball 14 is sealingly and slidingly connected to the hole wall of the pressure relief hole 13. By providing the pressure relief hole 13, the gas or liquid between the buffer rod 10 and the bottom of the buffer hole 9 can be pressed into the pressure relief hole 13 when the elastic member is compressed. The rubber ball 14 in the pressure relief hole 13 is used to balance the pressure of the pressure relief hole 13 on both sides above and below the rubber ball 14, so that the pressure at the lower end of the pressure relief hole 13 gradually increases with the compression of the elastic member, thereby achieving a buffering effect. Moreover, as the pressure increases, after the upper shaft 5 starts to rotate, the speed difference between the upper shaft 5 and the lower shaft 6 gradually decreases.

[0026] The buffer hole 9 is filled with hydraulic oil between its bottom and the lower end of the buffer rod 10. A throttle valve 15 is installed at the lower end of the pressure relief hole 13. The upper end of the pressure relief hole 13 is connected to the upper end of the upper shaft 5, and a ball support 16 is installed at the upper end of the upper shaft 5 to seal the upper end of the pressure relief hole 13. The elastic member is a disc spring 17. When the screw motor starts rotating, the rotor joint 7 drives the upper shaft 5 to rotate. At the moment of startup, the upper shaft 5 and the lower shaft 6 transmit torque through the first and second involute helical teeth 11 and 12. At the same time, the two are locked together by threaded engagement. During this locking process, the volume between the buffer rod 10 and the buffer hole 9 is compressed, and the hydraulic oil inside is released through the throttle valve 15. Due to the small flow orifice of the throttle valve 15, the pressure release occurs slowly. The squeezed hydraulic oil pushes the rubber ball 14 upward, compressing the air on the opposite side and squeezing the disc spring 17. After a period of pressure relief, the end faces of the upper shaft 5 and lower shaft 6 are completely in contact, and torque transmission is completed without relative movement. When the motor stops rotating, the disc spring pushes up the upper shaft 5, and the hydraulic oil under the rubber ball 14 is sucked between the buffer rod 10 and the buffer hole 9, returning to the initial state.

[0027] The wall of the buffer hole 9 is recessed with a mounting groove 18, and an anti-drop clip 19 is slidably provided in the mounting groove 18. The upper side of the anti-drop clip 19 is tilted downward to form a first inclined surface 20 at one end facing the buffer rod 10. The anti-drop clip 19 is connected to the bottom of the mounting groove 18 by a spring 21. A limiting groove 22 is recessed around the outer wall of the buffer rod 10. The upper groove wall of the limiting groove 22 is tilted upward from the groove bottom to the groove opening to form a second inclined surface 23. The end of the anti-drop clip 19 is clamped in the limiting groove 22 before the upper shaft body 5 rotates. By providing the anti-drop clip 19 and the limiting groove 22, during the downward movement of the buffer rod 10, the first inclined surface 20 and the second inclined surface 23 cooperate to push the anti-drop clip 19 back into the mounting groove 18, thereby allowing the buffer rod 10 to move downward smoothly. When the buffer rod 10 moves upward, when the anti-drop clip 19 moves to align with the limit groove 22, the elastic force of the spring 21 pushes the end of the anti-drop clip 19 into the limit groove 22, and the buffer rod 10 is organized to continue to move upward to prevent the upper shaft 5 and the lower shaft 6 from separating.

[0028] A sealing ring 24 is installed on the wall of the buffer hole 9 near the hole mouth, and the inner wall of the sealing ring 24 is sealed and fitted with the outer wall of the buffer rod 10; a first guide ring 25 is provided on the wall of the buffer hole 9 above and below the sealing ring 24, and the inner wall of the first guide ring 25 is slidingly fitted with the inner wall of the buffer rod 10; a second guide ring 26 is provided on the outer wall of the buffer rod 10 below the second involute bevel tooth 12, and the outer wall of the second guide ring 26 is slidingly fitted with the wall of the buffer hole 9; a connecting groove 43 is provided on the wall of the buffer hole 9, and an oil hole connected to the connecting groove 43 is provided on the outer wall of the lower shaft body 6, and an oil plug 44 for blocking the oil hole is provided on the outer wall of the lower shaft body 6 at the position of the oil hole. When installing the upper shaft body 5, first fill the buffer hole 9 with hydraulic oil, and then install the buffer rod 10 into the buffer hole 9. During the installation process, the buffer rod 10 will squeeze out the excess hydraulic oil through the connecting groove 43 and the oil hole. After the installation is completed, the oil hole can be sealed with the oil plug 44. The sealing ring 24 seals the gap between the buffer rod 10 and the buffer groove, preventing hydraulic oil from overflowing from the buffer groove and external mud from entering the buffer groove. The first guide ring 25 and the second guide ring 26 maintain a uniform gap and stability between the buffer rod 10 and the buffer hole 9 during relative motion, preventing the first and second involute helical teeth 11 and 12 from getting stuck.

[0029] The upper end of the rotor joint 7 is connected to the lower end of the rotor 2, and a connecting groove 27 is provided at the lower end. The inner wall of the connecting groove 27 is vertically provided with a first driving groove 40 connected to the lower side of the rotor joint 7. The upper end of the upper shaft body 5 is inserted into the connecting groove 27, and the outer wall of the upper shaft body 5 is provided with a driving block 29 matching the first driving groove 40. The driving block 29 is embedded in the first driving groove 40, and a gap is left between the driving block 29 and the first driving groove 40. The groove wall of the first driving groove 40 is recessed with a first transmission groove 41, and the side wall of the driving block 29 is provided with a second transmission groove 42 corresponding to the position of the first transmission groove 41. The first transmission groove 41 and the second transmission groove 42 cooperate to form an active cavity, and the arc roller 28 is movably provided in the active cavity; a connecting ring groove 30 is provided around the outer wall of the upper shaft body 5 below the driving block 29, and the notch of the connecting groove 27 is connected to a limiting ring 31, and the limiting ring 31 is movably provided in the connecting ring groove 30. The first driving groove 40 and the driving block 29 are as follows Figure 4 The setting shown is 4 or any other number is acceptable.

[0030] The width of the connecting ring groove 30 is greater than the width of the limiting ring 31. Such a setting, with the help of the cooperation between the limiting ring 31 and the connecting ring groove 30, can connect the rotor joint 7 and the upper shaft body 5 together, while allowing a certain degree of movement between the upper shaft body 5 and the rotor joint 7.

[0031] The arcuate roller 28 is movably arranged in the movable cavity, and a certain gap is left between it and the cavity wall of the movable cavity, so that the two sides of the arcuate roller 28 can be placed in the first transmission groove 41 and the second transmission groove 42 respectively. When the rotor joint 7 rotates, the arcuate roller 28 is pushed through the first drive groove 40 to drive the drive block 29 to move, thereby driving the upper shaft 5 to rotate.

[0032] The limiting ring 31 is installed in the notch of the connecting groove 27 through the fixing ring 32. The inner wall of the upper end of the fixing ring 32 is recessed to form a threaded ring groove 33. The upper groove wall of the threaded ring groove 33 is connected to the upper end of the fixing ring 32. The groove bottom of the threaded ring groove 33 is provided with a first thread, and the outer wall of the lower end of the rotor joint 7 is provided with a second thread. The first thread and the second thread are threadedly connected. The outer wall of the limiting ring 31 is provided with a snap ring 34, which is clamped between the lower end of the rotor joint 7 and the lower groove wall of the threaded ring groove 33. To facilitate the installation of the limiting ring 31, the limiting ring 31 can be in the form of two half rings. During installation, the two half rings of the limiting ring 31 are spliced ​​in the groove of the limiting ring 31. After splicing, when the fixing ring 32 is threadedly connected to the rotor joint 7, the snap ring 34 is fixed, thereby completing the installation of the limiting ring 31.

[0033] A flexible sealing sheet 35 is provided between the fixing ring 32 and the outer wall of the upper shaft body 5. The lower side of the flexible sealing sheet 35 is sealed to the outer wall of the upper shaft body 5, and the upper side is sealed to the inner wall of the fixing ring 32. The flexible sealing sheet 35 can seal the connection groove 27 to prevent mud from entering the connection groove 27.

[0034] The upper end of the water cap connector 8 is connected to the lower end of the lower shaft 6. The lower end of the water cap connector 8 is connected to the upper end of the drill bit via a transmission shaft 36. A TC bearing 37 is mounted on the outer wall of the transmission shaft 36. The surface of the TC bearing 37 is provided with a wear-resistant layer 38, and the surface of the wear-resistant layer 38 is provided with spiral grooves 39. Two TC bearings 37 are arranged in a set, with the inner and outer TC bearings 37 tightly fitting against the outer wall of the transmission shaft 36, while the outer TC bearing 37 tightly fits into the transmission shaft housing. The two TC bearings 37 are rotatably connected. The spiral grooves 39 allow mud to flow through. Simultaneously, when the motor rotates, it drives the TC bearings 37 to rotate. During rotation, the spiral grooves 39 squeeze out the mud inside and then draw in new mud, ensuring lubrication. This also allows for a smaller clearance between the inner and outer rings of the TC bearings 37. This advantage is that it prevents radial vibration of the TC bearings 37. The spiral grooves also provide cleaning, lubrication, and cooling, significantly increasing their service life and reducing vibration, thus ensuring transmission stability.

[0035] Although the present invention has been described herein with reference to a number of illustrative embodiments thereof, it will be understood that numerous other modifications and implementations may be devised by those skilled in the art that fall within the scope and spirit of the principles disclosed herein. More specifically, within the scope of the present disclosure, the drawings, and the claims, numerous variations and modifications may be made to the components and / or layout of the subject combination arrangement. In addition to variations and modifications to the components and / or layout, other uses will also be apparent to those skilled in the art.

Claims

1. A soft-start screw drill adapted for a rotary guide tool, comprising a housing (1), and a rotor (2), a universal joint (3), and a transmission shaft (36) sequentially mounted in the housing (1), wherein the lower end of the transmission shaft (36) is connected to the rotary guide tool below the housing (1), characterized in that: The universal joint (3) comprises an upper shaft body (5) and a lower shaft body (6), the upper end of the upper shaft body (5) is connected to the lower end of the rotor (2) via a rotor joint (7), the lower end of the lower shaft body (6) is connected to the upper end of the transmission shaft (36) via a water cap joint (8), the upper end of the lower shaft body (6) is provided with a buffer hole (9), the lower end of the upper shaft body (5) is provided with a buffer rod (10), a first involute bevel tooth (11) is provided on the hole wall surrounding the buffer hole (9), a second involute bevel tooth (12) is provided on the outer wall surrounding the buffer rod (10), the buffer rod (10) is installed in the buffer hole (9), and the first involute bevel tooth (11) is meshed with the second involute bevel tooth (12), the buffer hole (9) An elastic member is installed at the bottom of the hole, and the upper end of the elastic member is connected to the bottom of the buffer rod (10); a pressure relief hole (13) connected to the lower end of the buffer rod (10) is vertically arranged in the buffer rod (10), and a rubber ball (14) is slidably arranged in the pressure relief hole (13), and the rubber ball (14) is sealingly fitted and slidably connected to the hole wall of the pressure relief hole (13); the buffer hole (9) is filled with hydraulic oil between the bottom of the buffer hole (9) and the lower end of the buffer rod (10); a throttle valve (15) is installed at the lower end of the pressure relief hole (13), the upper end of the pressure relief hole (13) is connected to the upper end of the upper shaft body (5), and the upper end of the upper shaft body (5) is installed with a ball head support (16) for sealing the upper end of the pressure relief hole (13).

2. A soft-start screw drill adapted for a rotary guide tool according to claim 1, characterized in that: The elastic member is a disc spring (17).

3. The soft-start screw drill adapted for a rotary guide tool according to claim 1, characterized in that: A mounting groove (18) is recessed on the hole wall of the buffer hole (9), and an anti-drop clip (19) is slidably provided in the mounting groove (18). The upper side of the anti-drop clip (19) is tilted downward to form a first inclined surface (20) toward one end of the buffer rod (10). The anti-drop clip (19) is connected to the bottom of the mounting groove (18) through a spring (21). A limiting groove (22) is recessed around the outer wall of the buffer rod (10), and the upper groove wall of the limiting groove (22) is tilted upward from the groove bottom to the groove opening to form a second inclined surface (23). The end of the anti-drop clip (19) is clamped in the limiting groove (22) before the upper shaft body (5) rotates.

4. The soft-start screw drill adapted for a rotary guide tool according to claim 1, characterized in that: A sealing ring (24) is installed on the wall of the buffer hole (9) near the hole mouth, and the inner wall of the sealing ring (24) is sealed and fitted with the outer wall of the buffer rod (10); a first guide ring (25) is provided on the wall of the buffer hole (9) above and below the sealing ring (24), and the inner wall of the first guide ring (25) is slidably fitted with the inner wall of the buffer rod (10); a second guide ring (26) is provided on the outer wall of the buffer rod (10) below the second involute bevel gear (12), and the outer wall of the second guide ring (26) is slidably fitted with the wall of the buffer hole (9); the wall of the buffer hole (9) is provided with a connecting groove (43) connected to the outer wall of the lower shaft body (6).

5. The soft-start screw drill adapted for a rotary guide tool according to claim 1, characterized in that: The upper end of the rotor joint (7) is connected to the lower end of the rotor (2), and a connecting groove (27) is provided at the lower end. The inner wall of the connecting groove (27) is vertically provided with a first driving groove (40) that is connected to the lower side of the rotor joint (7). The upper end of the upper shaft (5) is inserted into the connecting groove (27), and the outer wall of the upper shaft (5) is provided with a driving block (29) that matches the first driving groove (40). The driving block (29) is embedded in the first driving groove (40), and a gap is left between the driving block (29) and the first driving groove (40). The groove wall of the first driving groove (40) is recessed to form a first transmission groove (41), and the side wall of the driving block (29) is provided with a second transmission groove (42) at a position corresponding to the first transmission groove (41). The first transmission groove (41) and the second transmission groove (42) cooperate to form an active cavity, and an arc roller (28) is movably provided in the active cavity; a connecting ring groove (30) is provided around the outer wall of the upper shaft body (5) below the driving block (29), and the notch of the connecting groove (27) is connected to a limiting ring (31), and the limiting ring (31) is movably provided in the connecting ring groove (30).

6. The soft-start screw drill adapted for a rotary guide tool according to claim 5, characterized in that: The limiting ring (31) is installed in the notch of the connecting groove (27) through the fixing ring (32), the inner wall of the upper end of the fixing ring (32) is recessed to form a threaded ring groove (33), the upper groove wall of the threaded ring groove (33) is communicated with the upper end of the fixing ring (32), the groove bottom of the threaded ring groove (33) is provided with a first thread, the outer wall of the lower end of the rotor joint (7) is provided with a second thread, the first thread and the second thread are threadedly connected, the outer wall of the limiting ring (31) is provided with a snap ring (34), and the snap ring (34) is clamped between the lower end of the rotor joint (7) and the lower groove wall of the threaded ring groove (33).

7. The soft-start screw drill adapted for a rotary guide tool according to claim 6, characterized in that: A flexible sealing sheet (35) is provided between the fixing ring (32) and the outer wall of the upper shaft body (5); the lower side of the flexible sealing sheet (35) is sealedly connected to the outer wall of the upper shaft body (5), and the upper side is sealedly connected to the inner wall of the fixing ring (32).

8. The soft-start screw drill adapted for a rotary guide tool according to claim 1, characterized in that: A TC bearing (37) is installed on the outer wall of the transmission shaft (36), a wear-resistant layer (38) is provided on the surface of the TC bearing (37), and a spiral groove (39) is provided on the surface of the wear-resistant layer (38).

Images