Soft start screw drill adaptive to rotary steering tool

Abstract

The invention relates to the technical field of screw drilling tools, in particular to a soft start screw drilling tool matched with a rotary steering tool, which comprises a shell as well as a rotor, a universal shaft and a transmission shaft which are sequentially mounted in the shell, the universal shaft comprises an upper shaft body and a lower shaft body, and the upper end of the upper shaft body is connected with the lower end of the rotor through a rotor joint; the lower end of the lower shaft body is connected with the upper end of a transmission shaft through a water cap connector, a buffering hole is formed in the upper end of the lower shaft body, a buffering rod is arranged at the lower end of the upper shaft body, first involute helical teeth are arranged on the hole wall surrounding the buffering hole, second involute helical teeth are arranged on the outer wall surrounding the buffering rod, and the buffering rod is installed in the buffering hole. The first involute helical teeth are meshed with the second involute helical teeth, an elastic piece is installed at the hole bottom of the buffering hole, and the upper end of the elastic piece is connected with the lower end of the buffering rod in an abutting-against mode. The problems that when a screw motor is started, high rotating speed and torque are instantly generated, certain impact is caused to a rotary steering tool, and the performance and the service life are affected are solved.

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 field is expanding from conventional oil and gas resources to unconventional oil and gas resources such as low permeability, deep and ultra-deep layers, deep ocean water, shale oil and gas. Rotary steerable drilling technology is a mature wellbore trajectory control technology at home and abroad. Most of the directional wells in the world use rotary steerable systems, which have the advantages of low friction torque, good wellbore quality, and high trajectory control automation, making them maturely applied in special wells such as large displacement wells, ultra-deep wells, and horizontal wells. Since the driving force of the rotary steerable system comes from the top drive, it is restricted by many factors such as the top drive torque output, top drive speed output, tool stick-slip vibration, and casing grinding, resulting in a low mechanical drilling speed when drilling in formations that are sensitive to speed. In order to achieve the purpose of improving efficiency, it is necessary to use a special screw for rotary guide. When the screw motor is started, it will instantly generate high speed and torque, which will cause a certain impact on the rotary steerable tool, thereby affecting its performance and life. Summary of the invention

[0003] The purpose of the present invention is to provide a soft-start screw drill adapted to a rotary guide tool, so as to solve the problem that the screw motor will instantly generate high speed and torque when starting, which will cause 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: A soft-start screw drill adapted to a rotary guide tool comprises a shell, and a rotor, a universal shaft and a transmission shaft which are 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 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 top contact.

[0005] 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.

[0006] 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 a ball head support for sealing the upper end of the pressure relief hole is installed at the upper end of the upper shaft body; the elastic member is a disc spring.

[0007] A further technical solution is that an installation groove is recessed on the hole wall of the buffer hole, and an anti-drop clip is slidably arranged in the installation groove. The upper side of the anti-drop clip is inclined downward to one end facing the buffer rod to form a first inclined surface, and the anti-drop clip is connected to the bottom of the installation groove through a spring. A limiting groove is recessed around the outer wall of the buffer rod, and 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, and the end of the anti-drop clip is clamped in the limiting groove before the upper shaft body rotates.

[0008] 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; the wall of the buffer hole is provided with a first guide ring 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; the outer wall of the buffer rod is provided with a second guide ring 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.

[0009] 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 driving 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 driving block matching the first driving groove. The driving block is embedded in the first driving groove, and a gap is left between the driving block and the first driving groove. The groove wall of the first driving groove is recessed with a first transmission groove, and the side wall of the driving 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 driving 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.

[0010] A further technical solution is that a limiting ring is installed in the notch of the connecting groove through a 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 threadably connected, and a clamping ring is provided on the outer wall of the limiting ring, which is clamped between the lower end of the rotor joint and the lower groove wall of the threaded ring groove.

[0011] 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 sealingly connected to the outer wall of the upper shaft body, and the upper side is sealingly connected to the inner wall of the fixing ring.

[0012] A further technical solution is that a TC bearing is installed on the outer wall of the transmission shaft, a wear-resistant layer is arranged on the surface of the TC bearing, and a spiral groove is arranged on the surface of the wear-resistant layer.

[0013] 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 body to rotate, and the upper shaft body 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 gradually drives the lower shaft body to rotate in the process of compressing the elastic member. When the end faces of the upper shaft body and the lower shaft body 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 body and the lower shaft body rotate at the same speed, and in the process of the upper shaft body moving toward the bottom of the lower shaft body groove through the involute bevel gear, the hydraulic oil between the upper shaft body and the lower shaft body will flow into the pressure relief hole of the upper shaft body through the throttle valve, and then the pressure balance at both ends is adjusted by the rubber ball. In the process from the upper shaft body starting to rotate to the lower shaft body rotating at the same speed as the upper shaft body, 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 as to continue to play a buffering role when starting next time. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The present invention is a schematic diagram of a soft-start screw drill adapted for a rotary guide tool.

[0015] Figure 2 for Figure 1 A partial enlarged schematic diagram of the area marked A in the middle.

[0016] Figure 3 for Figure 1 A partial enlarged schematic diagram of the area marked B in the middle.

[0017] Figure 4 It is a horizontal cross-sectional schematic 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.

[0018] Figure 5 The present invention is a schematic diagram of a TC bearing of a soft-start screw drill adapted for a rotary guide tool.

[0019] Icons: 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-installation slot, 19-anti-drop clip, 20-first inclined plane, 21-spring, 22-limiting slot, 23-second inclined plane, 2 4-sealing ring, 25-first guide ring, 26-second guide ring, 27-connecting groove, 28-arc 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 driving groove, 41-first transmission groove, 42-second transmission groove, 43-communication groove, 44-oil plug. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with 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.

[0021] Figures 1 to 5 The embodiment of the present invention is shown in FIG. Example: A soft-start screw drill adapted for a rotary guide tool comprises a shell 1, and a rotor 2, a universal shaft 3 and a transmission shaft 36 which are sequentially installed in the shell 1. The lower end of the transmission shaft 36 is connected to a 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. At the time of starting, the rotor 2 drives the upper shaft 5 to rotate, and the upper shaft 5 gradually moves toward the bottom of the buffer hole 9 through the cooperation of the first involute bevel gear 11 and the second involute bevel gear 12, and gradually compresses the elastic member, and gradually drives the lower shaft 6 to rotate during the compression of the elastic member. When the end faces of the upper shaft 5 and the lower shaft 6 are in contact, the first involute bevel gear 11 and the second involute bevel gear 12 cannot move relative to each other. At this time, the upper shaft 5 and the lower shaft 6 rotate at the same speed, and during the movement of the upper shaft 5 to the bottom of the groove of the lower shaft 6 through the involute bevel gear, the hydraulic oil between the upper shaft 5 and the lower shaft 6 will flow 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 through the rubber ball 14. In the process from the upper shaft 5 starting to rotate to the lower shaft 6 rotating at the same speed as the upper shaft 5, the adverse effect 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.

[0022] 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 slidably connected to the hole wall of the pressure relief hole 13 in a sealing and fitting manner. 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, and the pressure of the pressure relief hole 13 on both sides of the rubber ball 14 can be balanced by means of the rubber ball 14 in the pressure relief hole 13, so that the pressure at the lower end of the pressure relief hole 13 gradually increases with the compression of the elastic member to play a buffering effect, and as the pressure increases, after the upper shaft body 5 starts to rotate, the speed difference between the upper shaft body 5 and the lower shaft body 6 gradually decreases.

[0023] 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; the lower end of the pressure relief hole 13 is installed with a throttle valve 15, 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; the elastic member is a disc spring 17. When the screw motor starts to rotate, the upper shaft body 5 is driven to rotate through the rotor joint 7. At the moment of starting, the upper shaft body 5 and the lower shaft body 6 transmit torque through the first involute bevel gear 11 and the second involute bevel gear 12, and the two are locked with each other by screwing. During the locking process, the volume between the buffer rod 10 and the buffer hole 9 is compressed, and the internal hydraulic oil is depressurized through the throttle valve 15. Since the flow hole of the throttle valve 15 is very small, slow depressurization will occur. The extruded hydraulic oil pushes the rubber ball 14 to the upper end. The air on the opposite side is compressed, and the disc spring 17 is squeezed at the same time. After a period of pressure relief, the end faces of the upper shaft body 5 and the lower shaft body 6 are completely fitted, and the torque is transmitted without relative movement. When the motor stops rotating, the disc spring pushes up the upper shaft body 5, and the hydraulic oil under the rubber ball 14 is sucked between the buffer rod 10 and the buffer hole 9, and the initial state is restored.

[0024] The hole wall of the buffer hole 9 is provided 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 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 provided in the outer wall around the buffer rod 10. The upper groove wall of the limiting groove 22 is tilted upward from the bottom of the groove 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, in the process of the buffer rod 10 moving downward, the anti-drop clip 19 is pushed back into the mounting groove 18 with the help of the cooperation of the first inclined surface 20 and the second inclined surface 23, so that the buffer rod 10 can 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 end of the anti-drop clip 19 is pushed into the limit groove 22 by the elastic force of the spring 21, and the buffer rod 10 is organized to continue to move upward to prevent the upper shaft body 5 and the lower shaft body 6 from detaching.

[0025] The wall of the buffer hole 9 is provided with a sealing ring 24 near the hole opening, and the inner wall of the sealing ring 24 is sealed and fitted with the outer wall of the buffer rod 10; the wall of the buffer hole 9 is provided with a first guide ring 25 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; the outer wall of the buffer rod 10 is provided with a second guide ring 26 below the second involute helical tooth 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, the outer wall of the lower shaft body 6 is provided with an oil hole connected to the connecting groove 43, and the outer wall of the lower shaft body 6 is provided with an oil plug 44 for blocking the oil hole 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, and the oil hole can be sealed by the oil plug 44 after the installation is completed. By providing the sealing ring 24, the gap between the buffer rod 10 and the buffer groove can be sealed to prevent the hydraulic oil from overflowing from the buffer groove and the external mud from entering the buffer groove. By providing the first guide ring 25 and the second guide ring 26, the buffer rod 10 and the buffer hole 9 can maintain a uniform gap and stability during relative movement to prevent the first involute bevel gear 11 and the second involute bevel gear 12 from getting stuck.

[0026] 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 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. The first driving groove 40 and the driving block 29 are as shown in FIG. Figure 4 The setting shown is 4 or any other number is acceptable.

[0027] 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.

[0028] The arcuate roller 28 is movably arranged in the movable cavity, and a certain gap is left between the arcuate roller 28 and the cavity wall of the movable cavity, so that the two sides of the arcuate roller 28 can be respectively placed in the first transmission groove 41 and the second transmission groove 42. When the rotor joint 7 rotates, the arcuate roller 28 is pushed through the first driving groove 40 to drive the driving block 29 to move, thereby driving the upper shaft 5 to rotate.

[0029] 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. 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 matched and connected. The outer wall of the limiting ring 31 is provided with a clamping ring 34. The clamping ring 34 is clamped between the lower end of the rotor joint 7 and the lower groove wall of the threaded ring groove 33. In order to facilitate the installation of the limiting ring 31, the limiting ring 31 can be in the form of two half rings. When installing, 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 clamping ring 34 is fixed, thereby completing the installation of the limiting ring 31.

[0030] 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. By providing the flexible sealing sheet 35, the connection groove 27 can be sealed to prevent mud from entering the connection groove 27.

[0031] The upper end of the water cap joint 8 is connected to the lower end of the lower shaft body 6, and the lower end of the water cap joint 8 is connected to the upper end of the drill bit through the transmission shaft 36. The outer wall of the transmission shaft 36 is equipped with a TC bearing 37, and 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 a spiral groove 39. Two TC bearings 37 are in a group, and the inner and outer TC bearings 37 are tightly matched with the outer wall of the transmission shaft 36, and the outer TC bearing 37 is tightly matched with the transmission shaft housing, and the inner and outer TC bearings 37 are connected in rotation. The spiral groove 39 allows mud to flow through. At the same time, when the motor rotates, the TC bearing 37 will be driven to rotate. During the rotation process, the spiral groove 39 will squeeze out the internal mud, and then suck in new mud to ensure lubrication. At the same time, the inner and outer ring design gaps of the TC bearing 37 can be designed to be smaller. This has the advantage of avoiding radial vibration of the TC bearing 37, and the spiral can clean, lubricate and cool down, greatly improving the service life and shock absorption, and ensuring the stability of the transmission.

[0032] Although the present invention is described herein with reference to a number of illustrative embodiments of the present invention, it will be appreciated that those skilled in the art may devise many other modifications and implementations that fall within the scope and spirit of the principles disclosed herein. More specifically, within the scope of the present disclosure, drawings, and claims, a variety of variations and modifications may be made to the components and / or layout of the subject combination layout. In addition to the variations and modifications made 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 shaft (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 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) 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); a buffer hole (9) is provided at the upper end of the lower shaft body (6); a buffer rod (10) is provided at the lower end of the upper shaft body (5); a first involute bevel tooth (11) is provided on a hole wall surrounding the buffer hole (9); a second involute bevel tooth (12) is provided on an 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); the upper end of the elastic member is connected to the lower end of the buffer rod (10) by abutting contact.

2. A soft-start screw drill adapted for a rotary guide tool according to claim 1, characterized in that: A pressure relief hole (13) connected to the lower end of the buffer rod (10) is vertically arranged in the buffer rod (10), a rubber ball (14) is slidably arranged in the pressure relief hole (13), and the rubber ball (14) is slidably connected to the hole wall of the pressure relief hole (13) in a sealing fit.

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

4. 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 arranged in the mounting groove (18). The upper side of the anti-drop clip (19) is inclined 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 groove 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 inclined 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.

5. 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 arranged 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 arranged 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).

6. A 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. A first driving groove (40) which is in communication with the lower side of the rotor joint (7) is vertically provided on the inner wall of the connecting groove (27). The upper end of the upper shaft body (5) is inserted into the connecting groove (27), and a driving block (29) which matches the first driving groove (40) is provided on the outer wall of the upper shaft body (5). 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). A first transmission groove (41) is recessed in the groove wall of the first driving groove (40), and a second transmission groove (42) is provided on the side wall of the driving block (29) 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 surface roller (28) is movably arranged 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 a notch of the connecting groove (27) is connected to a limiting ring (31), and the limiting ring (31) is movably arranged in the connecting ring groove (30).

7. A soft-start screw drill adapted for a rotary guide tool according to claim 6, characterized in that: The limiting ring (31) is mounted on the notch of the connecting groove (27) through a 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 threadably connected; the outer wall of the limiting ring (31) is provided with a clamping ring (34); the clamping ring (34) is clamped between the lower end of the rotor joint (7) and the lower groove wall of the threaded ring groove (33).

8. A soft-start screw drill adapted for a rotary guide tool according to claim 7, 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 sealingly connected to the outer wall of the upper shaft body (5), and the upper side is sealingly connected to the inner wall of the fixing ring (32).

9. The soft-start screw drill adapted for a rotary guide tool according to claim 1, characterized in that: A TC bearing (37) is mounted 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).

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