Improved oscillating pulse power screw drill

Abstract

The application relates to an oscillating pulse screw drill tool with improved shaft stress, which comprises a drill tool body, a static valve assembly and a dynamic valve assembly. The drill tool body comprises a shell and a shaft, the shell is a hollow tubular structure, and the shaft is located in the shell and can rotate in the shell. The static valve assembly comprises a static valve shell coaxially connected with the shell, and a static valve flow channel is arranged in the static valve shell. The dynamic valve assembly is axially gap-connected with the static valve assembly, and comprises a dynamic valve seat fixed on the top of the shaft, and a dynamic valve flow channel is arranged in the dynamic valve seat. The dynamic valve assembly rotates eccentrically relative to the static valve assembly to periodically change the flow area between the static valve flow channel and the dynamic valve flow channel. The dynamic valve assembly of the application is gap-connected with the static valve assembly, the static valve assembly directly transmits the axial force borne by the static valve assembly to the static valve shell, and does not directly transmit the axial force to the dynamic valve assembly. Therefore, the shaft can bear additional axial force, rotating friction resistance and bending moment, the service life of the shaft and the bearing system of the screw drill tool is prolonged, and the efficiency of the whole screw drill tool is improved.

Description

Technical Field

[0001] This application relates to the field of screw drilling tools, and in particular to oscillating pulse screw drilling tools that improve the stress on the shaft. Background Technology

[0002] A screw drill is a type of positive displacement downhole power drill that uses drilling fluid as its power source, converting liquid pressure energy into mechanical energy. When the mud pumped out by the mud pump flows through the bypass valve into the motor, a certain pressure difference is formed between the motor's inlet and outlet, driving the rotor to rotate around the stator's axis. The rotational speed and torque are then transmitted to the drill bit through the universal joint and drive shaft, thereby realizing the drilling operation.

[0003] In the field of oil extraction, when drilling long-reach wells, wells with medium and short curvature radii, and horizontal wells, the drill string is subject to frictional resistance from the well wall, making it impossible to apply accurate drilling pressure to the drill bit, which seriously affects drilling efficiency. Therefore, reducing the frictional resistance of the drill string, effectively feeding the drill string, and accurately applying drilling pressure to the drill bit are important issues in solving the drilling technology of complex wells.

[0004] The oscillating screw drill string is an effective tool for reducing the frictional resistance of the screw drill string and effectively transmitting drilling pressure. This tool effectively reduces the frictional resistance between the drill string and the well wall during drilling and improves drilling rock breaking efficiency through the periodic axial vibration generated by pulse pressure.

[0005] Currently, common oscillating screw drill pulse devices employ a face-fitting system between a stationary valve and a moving valve. The rotor and the moving valve plate connected to it rotate eccentrically around the stator housing. This eccentric motion causes the flow area between the moving and stationary valve plates to change periodically, achieving hydraulic pulse oscillation. A spring is designed into the stationary valve device to ensure that the mating surfaces of the stationary and moving valve plates maintain constant frictional contact.

[0006] During operation, the stationary valve undergoes axial displacement under hydraulic pressure. This stationary valve transmits the axial force it bears to the moving valve connected to the screw drill shaft. The screw drill shaft is subjected to significant axial force, rotational friction resistance, and bending moment, increasing the load stress on the screw drill shaft and bearing system, and reducing the overall efficiency of the screw drill. Simultaneously, because the axial force generated by the stationary valve acts on the moving valve and its shaft, only a portion of the oscillation force generated by the pulse device acts on the screw drill housing, reducing the screw drill's friction-reducing and resistance-reducing effects. Summary of the Invention

[0007] This application provides an oscillating pulse screw drill tool to improve the stress on the shaft, thereby solving the problem in related technologies where the axial force generated by the static valve acts on the dynamic valve and the shaft on which it is located, resulting in the shaft being subjected to large axial force, rotational friction resistance and bending moment, which increases the load stress on the screw drill tool shaft and bearing system and reduces the overall efficiency of the screw drill tool.

[0008] This application provides an oscillating pulse screw drill tool for improving shaft stress, including:

[0009] The drill bit body includes a housing and a shaft. The housing is a hollow tubular structure, and the shaft is located inside the housing and can rotate within the housing.

[0010] A static valve assembly, comprising a static valve housing coaxially connected to a housing, wherein a static valve flow channel is provided within the static valve housing;

[0011] A moving valve assembly, which is axially clearance-fitted with a stationary valve assembly, includes a moving valve seat fixed to the top of a shaft, and the moving valve seat is provided with a moving valve flow passage;

[0012] The moving valve assembly rotates eccentrically relative to the stationary valve assembly to periodically change the flow area between the stationary valve flow channel and the moving valve flow channel.

[0013] In some embodiments, the stationary valve assembly further includes a stationary valve plate fixedly connected to the lower end of the stationary valve housing, and the stationary valve flow channel is located on the stationary valve plate.

[0014] In some embodiments: the lower end of the stationary valve housing is provided with a positioning locking sleeve for fixing the stationary valve plate to the stationary valve housing, the positioning locking sleeve being threadedly connected to the stationary valve housing to restrict the stationary valve plate from moving toward the moving valve seat.

[0015] In some embodiments, an axial gap or elastic element is pre-set between the stationary valve plate and the stationary valve housing to allow the stationary valve plate to move away from the moving valve seat;

[0016] The stationary valve plate is coaxially located inside the positioning and locking sleeve, and a first adjusting shim is provided between the stationary valve plate and the positioning and locking sleeve to adjust the axial clearance between the stationary valve plate and the moving valve seat.

[0017] In some embodiments, the stationary valve plate and the positioning locking sleeve are connected by a flat key or spline, the flat key or spline being used to restrict the stationary valve plate from rotating circumferentially within the positioning locking sleeve.

[0018] In some embodiments: the moving valve seat is provided with a moving valve plate at one end near the stationary valve plate, the moving valve flow channel is located on the moving valve plate, and the axial distance between the moving valve plate and the stationary valve plate is 0.2-6mm;

[0019] The moving valve seat has multiple bypass channels that communicate with the moving valve flow channel.

[0020] In some embodiments: the housing includes a stator housing and an anti-drop housing that are threaded together; the shaft includes a screw rotor located within the stator housing and an anti-drop rod located within the anti-drop housing;

[0021] The moving valve seat is threadedly connected to the upper end of the anti-drop rod, the lower end of the anti-drop rod is connected to the screw rotor, and the anti-drop rod is provided with an anti-drop washer.

[0022] In some embodiments: the lower end of the anti-drop rod is threadedly connected to the screw rotor via a connector, and a second adjusting shim is provided between the connector and the anti-drop rod to adjust the axial clearance between the moving valve assembly and the stationary valve assembly.

[0023] In some embodiments: the top end of the static valve housing is provided with a threaded hole, the static valve flow channel is located at the lower end of the static valve housing, and a hydraulic enhancement and amplification cavity is connected between the threaded hole and the static valve flow channel, the diameter of the hydraulic enhancement and amplification cavity being larger than the diameter of the threaded hole and the static valve flow channel.

[0024] In some embodiments: the axis of the stationary valve flow channel is collinear with the axis of the stationary valve housing, the axis of the moving valve flow channel is offset away from the axis of the stationary valve flow channel, and the distance between the axis of the moving valve flow channel and the axis of the stationary valve flow channel is 5-15mm.

[0025] The beneficial effects of the technical solution provided in this application include:

[0026] This application provides an oscillating pulse screw drill tool to improve the stress on the shaft. The oscillating pulse screw drill tool includes a drill body comprising a housing and a shaft. The housing is a hollow tubular structure, and the shaft is located within the housing and can rotate within it. A stationary valve assembly includes a stationary valve housing coaxially connected to the housing, with a stationary valve flow channel within the housing. A moving valve assembly is axially clearance-fitted with the stationary valve assembly and includes a moving valve seat fixed to the top of the shaft, with a moving valve flow channel. The moving valve assembly rotates eccentrically relative to the stationary valve assembly to periodically change the flow area between the stationary valve flow channel and the moving valve flow channel.

[0027] Therefore, when the screw drill bit of this application drives the moving valve assembly, the flow area of ​​the drilling fluid flowing through the stationary valve channel and the moving valve channel changes periodically. A pulsed hydraulic pressure is generated at the upper end of the stationary valve channel. Due to the axial clearance fit between the moving valve assembly and the stationary valve assembly, the stationary valve assembly directly transmits the axial force it bears to the stationary valve housing, rather than directly to the moving valve assembly. This reduces the additional axial force, rotational friction resistance, and bending moment borne by the shaft, extending the service life of the screw drill bit's shaft and bearing system, and improving the overall efficiency of the screw drill bit. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structure of an embodiment of this application;

[0030] Figure 2 This is a schematic diagram of another embodiment of the present application;

[0031] Figure 3 This is a schematic diagram of the structure of yet another embodiment of this application;

[0032] Figure 4 for Figure 3 A magnified view of a portion of point A in the middle.

[0033] Figure label:

[0034] 1. Drill tool body; 11. Stator housing; 12. Screw rotor; 13. Anti-drop housing; 14. Anti-drop rod; 15. Connector; 16. Second adjusting shim; 17. Anti-drop shim;

[0035] 2. Static valve assembly; 21. Static valve housing; 22. Static valve flow channel; 23. Static valve plate; 24. Positioning locking sleeve; 25. First adjusting shim; 26. Hydraulic enhancement and amplification chamber; 27. Axial clearance;

[0036] 3. Moving valve assembly; 31. Moving valve seat; 32. Moving valve plate; 33. Moving valve flow passage; 34. Bypass flow passage. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] This application provides an oscillating pulse screw drill tool that improves the stress on the shaft. It can solve the problem in related technologies where the axial force generated by the static valve acts on the dynamic valve and the shaft on which it is located, resulting in the shaft being subjected to large axial force, rotational friction resistance and bending moment, which increases the load stress on the screw drill tool shaft and bearing system and reduces the overall efficiency of the screw drill tool.

[0039] See Figure 1As shown, this application provides an oscillating pulse screw drill tool for improving shaft stress, comprising:

[0040] The drill bit body 1 includes a housing and a shaft. The housing is a hollow tubular structure, and the shaft is located inside the housing and can rotate within it. During normal drilling operations, the mud pumped by the mud pump flows into the housing through a bypass valve, creating a pressure difference between the inlet and outlet of the housing. This pressure difference drives the shaft to rotate around the axis of the housing, and transmits the rotational speed and torque to the drill bit through a universal joint and a drive shaft, thereby achieving drilling operations.

[0041] The static valve assembly 2 includes a static valve housing 21 located at the top of the housing and coaxially threadedly connected to the housing. A static valve flow channel 22 is provided within the static valve housing 21. The static valve housing 21 of the static valve assembly 2 is fixedly connected to the housing coaxially via threads, so that the axial oscillation pulses generated by the static valve assembly 2 are transmitted to the housing, converting the static friction between the downhole drill string and the wellbore into dynamic friction, thus relieving the pressure on the drill string.

[0042] The moving valve assembly 3 is axially clearance-fitted with the stationary valve assembly 2. The moving valve assembly 3 includes a moving valve seat 31 fixed to the top of the shaft, and the moving valve seat 31 is provided with a moving valve flow channel 33. The shaft drives the moving valve assembly 3 to rotate eccentrically relative to the stationary valve assembly 2 to periodically change the flow area between the stationary valve flow channel 22 and the moving valve flow channel 33, thereby generating periodic pressure pulses. These pressure pulses act on the upper stationary valve housing 21, causing the housing to peristalsize axially.

[0043] When the screw drill bit of this embodiment drives the moving valve assembly 3, the flow area of ​​the drilling fluid flowing through the stationary valve channel 22 and the moving valve channel 33 changes periodically. A pulsed hydraulic pressure is generated at the upper end of the stationary valve channel 22. Due to the axial clearance fit between the moving valve assembly 3 and the stationary valve assembly 2, the stationary valve assembly 2 directly transmits the axial force it bears to the stationary valve housing 21, rather than directly to the moving valve assembly 3. Therefore, the additional axial force, rotational friction resistance, and bending moment borne by the shaft can be reduced, extending the service life of the screw drill bit's shaft and bearing system, and improving the overall efficiency of the screw drill bit.

[0044] In some alternative embodiments: see Figure 1 and Figure 2 As shown, this application embodiment provides an oscillating pulse screw drill tool to improve the stress on the shaft. The stationary valve assembly 2 of this oscillating pulse screw drill tool further includes a stationary valve plate 23 fixedly connected to the lower end of the stationary valve housing 21, with a stationary valve flow channel 22 located on the stationary valve plate 23. The stationary valve plate 23 is connected to the lower end of the stationary valve housing 21 by an interference fit and welded, or it can be fixed by a threaded connection. Figure 1As shown, the stationary valve plate 23 and the stationary valve housing 21 of the stationary valve assembly 2 can also be designed as an integral unit. This embodiment can minimize the number of parts in the stationary valve assembly 2. The surface of the stationary valve plate 23 is chrome-plated or sprayed with tungsten carbide to prevent erosion.

[0045] In some alternative embodiments: see Figure 3 and Figure 4 As shown in the embodiment of this application, an oscillating pulse screw drill tool for improving shaft stress is provided. The lower end of the stationary valve housing 21 of this oscillating pulse screw drill tool is provided with a positioning locking sleeve 24 for fixing the stationary valve plate 23 to the stationary valve housing 21. The positioning locking sleeve 24 is threadedly connected to the stationary valve housing 21 to restrict the movement of the stationary valve plate 23 toward the moving valve seat 31. The outer circle of the stationary valve plate 23 mates with the inner hole of the positioning locking sleeve 24 to fix the stationary valve plate 23 to the lower end of the stationary valve housing 21.

[0046] An axial clearance 27 or elastic element is pre-set between the stationary valve plate 23 and the stationary valve housing 21 to allow the stationary valve plate 23 to move away from the moving valve seat 31; an axial clearance 27 or elastic element is designed between the upper end face of the stationary valve plate 23 and the inner hole limiting shoulder face of the stationary valve housing 21 to prevent the internal shaft of the drill body from impacting the stationary valve plate 23 when it moves upward relative to the housing as a whole, thereby increasing the friction between the moving valve assembly 3 and the stationary valve assembly 2, which would lead to wear or damage to the moving and stationary valve plates 23.

[0047] In some alternative embodiments: see Figure 3 and Figure 4 As shown in the embodiment of this application, an oscillating pulse screw drill tool is provided to improve the stress on the shaft. The stationary valve plate 23 of the oscillating pulse screw drill tool is coaxially located within the positioning locking sleeve 24. A first adjusting shim 25 is provided between the stationary valve plate 23 and the positioning locking sleeve 24 to adjust the axial clearance between the stationary valve plate 23 and the moving valve seat 31. The stationary valve plate 23 and the positioning locking sleeve 24 are connected by a flat key or spline to restrict the circumferential rotation of the stationary valve plate 23 within the positioning locking sleeve 24.

[0048] The first adjusting shim 25 in this embodiment is used to adjust the end face gap between the stationary valve plate 23 and the moving valve seat 31 to ensure that the pulse pressure value is within the design range. The larger the end face gap between the stationary valve plate 23 and the moving valve seat 31, the smaller the pulse pressure value acting on the stationary valve assembly 2. However, it is necessary to avoid mutual contact and friction between the stationary valve plate 23 and the moving valve seat 31. The stationary valve plate 23 and the positioning locking sleeve 24 are connected by a flat key or spline to prevent the stationary valve plate 23 from rotating relative to the positioning locking sleeve 24.

[0049] In some alternative embodiments: see Figures 1 to 4As shown in the embodiment of this application, an oscillating pulse screw drill tool with improved shaft stress is provided. The oscillating pulse screw drill tool has a moving valve seat 31 with a moving valve plate 32 near the stationary valve plate 23. A moving valve flow channel 33 is located on the moving valve plate 32, and the axial distance between the moving valve plate 32 and the stationary valve plate 23 is 0.2-6 mm. The specific axial distance between the moving valve plate 32 and the stationary valve plate 23 can be calculated based on the required pulse force. Multiple bypass flow channels 34 communicating with the moving valve flow channel 33 are provided on the moving valve seat 31. The bypass flow channels 34 are used to introduce drilling fluid into the meshing surface between the casing and the shaft, driving the screw drill tool shaft to rotate.

[0050] In some alternative embodiments: see Figures 1 to 4 As shown in the embodiment of this application, an oscillating pulse screw drill tool with improved shaft stress is provided. The housing of this oscillating pulse screw drill tool specifically includes a stator housing 11 and an anti-drop housing 13 connected by threads. The shaft includes a screw rotor 12 located within the stator housing 11 and an anti-drop rod 14 located within the anti-drop housing 13. A moving valve seat 31 is threadedly connected to the upper end of the anti-drop rod 14, and the lower end of the anti-drop rod 14 is connected to the screw rotor 12. An anti-drop washer 17 is provided on the anti-drop rod 14. The maximum outer diameter of the anti-drop washer 17 is larger than the minimum inner diameter of the anti-drop housing 13. When the connecting threads between the screw drill tool housings fail, it is used to prevent the screw rotor 12 and the lower end parts connected to the screw rotor 12 from falling into the well.

[0051] The lower end of the anti-drop rod 14 is threadedly connected to the screw rotor 12 via a connector 15. A second adjusting shim 16 is provided between the connector 15 and the anti-drop rod 14 to adjust the clearance between the moving valve assembly 3 and the stationary valve assembly 2. The second adjusting shim 16 is used to compensate for the length error and bearing clearance of the screw rotor 12 and the anti-drop rod 14. Its function is to ensure that the pulse pressure value is within the design range by adjusting the fitting clearance between the stationary valve assembly 2 and the moving valve assembly 3.

[0052] In some alternative embodiments: see Figures 1 to 3 As shown, this application embodiment provides an oscillating pulse screw drill tool to improve the stress on the shaft. The static valve housing 21 of the oscillating pulse screw drill tool has a threaded hole at the top end, and the static valve flow channel 22 is located at the lower end of the static valve housing 21. A hydraulic enhancement and amplification cavity 26 is connected between the threaded hole and the static valve flow channel 22. The diameter of the hydraulic enhancement and amplification cavity 26 is larger than the diameter of the threaded hole and the static valve flow channel 22.

[0053] In this embodiment, a hydraulic enhancement and amplification cavity 7 is provided in the inner hole of the static valve housing 21 of the static valve assembly 2. This hydraulic enhancement and amplification cavity 7 is located between the threaded hole and the static valve flow channel 22 of the static valve housing 21. The diameter of the hydraulic enhancement and amplification cavity 7 is larger than the diameter of the threaded hole and the static valve flow channel 22, which increases the area of ​​hydraulic pressure action, thereby improving the axial oscillation force and reducing the tubing pressure. This structure is suitable for drilling with enhanced parameters and can further improve the mechanical drilling rate.

[0054] In some alternative embodiments: see Figures 1 to 3 As shown in the embodiment of this application, an oscillating pulse screw drill tool for improving shaft stress is provided. The axis of the stationary valve flow channel 22 of this oscillating pulse screw drill tool is collinear with the axis of the stationary valve housing 21, while the axis of the moving valve flow channel 33 is offset away from the axis of the stationary valve flow channel 22. The distance between the axis of the moving valve flow channel 33 and the axis of the stationary valve flow channel 22 is 5-15 mm. The specific distance between the axis of the moving valve flow channel 33 and the axis of the stationary valve flow channel 22 can be calculated based on the required pulse force.

[0055] Working principle:

[0056] This application utilizes drilling mud pumped through a mud pump to enter the inner hole of the upper housing of the screw drill string via the drill pipe. The drilling fluid passes through the static valve flow channel 22, the moving valve flow channel 33, and the bypass flow channel 34 of the moving valve seat 31 in the static valve assembly 2, and enters the stator housing 11, driving the screw rotor 12 to rotate. Simultaneously, the screw rotor 12 rotates, driving the lower universal joint and drive shaft to work. Simultaneously, the rotor drives the upper anti-drop rod 14 to move. Because the anti-drop rod 14 is equipped with a moving valve plate 32, and due to the eccentricity between the shaft centerline and the housing centerline, the anti-drop rod 14 drives the moving valve plate 32 to move eccentrically around the static valve plate 23. This causes the flow area between the static valve flow channel 22 and the moving valve flow channel 33 to periodically increase and decrease, generating periodic pressure pulses. These pressure pulses act on the upper static valve housing 21, causing the housing to creep axially, converting the static friction between the downhole drill string and the wellbore into dynamic friction, thus relieving the pressure on the drill string.

[0057] This application features a simple structure, possessing not only the power and safety of conventional screw drills but also utilizing the screw drill's own surplus energy to supply the static valve assembly 2, thereby generating the pulse pressure wave required for axial oscillation. This ensures the downhole drill string can smoothly transmit drilling pressure to the drill bit, improving drilling efficiency. Compared to other similar tools, this application reduces the axial force and rotational friction resistance on the screw drill shaft, extending the service life of the oscillating pulse screw drill and improving the overall efficiency of the oscillating pulse screw drill, significantly contributing to improved drilling efficiency and shortened drilling cycles. Furthermore, the pulse pressure of this screw drill is easily adjustable; the hydraulic pulse pressure can be adjusted by modifying the flow area, axial spacing, or eccentricity of the static valve flow channel 22 and the dynamic valve flow channel 33.

[0058] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0059] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0060] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An oscillating pulse screw drill bit for improving shaft stress, characterized in that, include: The drill body (1) includes a housing and a shaft. The housing is a hollow tubular structure, and the shaft is located inside the housing and can rotate inside the housing. The static valve assembly (2) includes a static valve housing (21) coaxially connected to the housing, and a static valve flow channel (22) is provided inside the static valve housing (21). The moving valve assembly (3) is axially clearance-fitted with the stationary valve assembly (2), and includes a moving valve seat (31) fixed on the top of the shaft, the moving valve seat (31) being provided with a moving valve flow channel (33). The moving valve assembly (3) rotates eccentrically relative to the stationary valve assembly (2) to periodically change the flow area between the stationary valve flow channel (22) and the moving valve flow channel (33); The static valve assembly (2) also includes a static valve plate (23) fixedly connected to the lower end of the static valve housing (21), and the static valve flow channel (22) is located on the static valve plate (23); The lower end of the static valve housing (21) is provided with a positioning locking sleeve (24) for fixing the static valve plate (23) on the static valve housing (21). The positioning locking sleeve (24) is threadedly connected to the static valve housing (21) to restrict the static valve plate (23) from moving toward the moving valve seat (31). An axial gap (27) or elastic element is pre-set between the stationary valve plate (23) and the stationary valve housing (21) to allow the stationary valve plate (23) to move away from the moving valve seat (31); The stationary valve plate (23) is coaxially located inside the positioning locking sleeve (24), and a first adjusting shim (25) is provided between the stationary valve plate (23) and the positioning locking sleeve (24) to adjust the axial gap between the stationary valve plate (23) and the moving valve seat (31). The stationary valve plate (23) and the positioning locking sleeve (24) are connected by a flat key or spline, which restricts the stationary valve plate (23) from rotating circumferentially within the positioning locking sleeve (24).

2. The oscillating pulse screw drill bit for improving shaft stress as described in claim 1, characterized in that: The moving valve seat (31) is provided with a moving valve plate (32) at one end near the stationary valve plate (23), the moving valve flow channel (33) is located on the moving valve plate (32), and the axial distance between the moving valve plate (32) and the stationary valve plate (23) is 0.2-6mm; The moving valve seat (31) is provided with multiple bypass channels (34) that communicate with the moving valve flow channel (33).

3. The oscillating pulse screw drill bit for improving shaft stress as described in claim 1, characterized in that: The housing includes a stator housing (11) and an anti-drop housing (13) that are threaded together. The shaft includes a screw rotor (12) located in the stator housing (11) and an anti-drop rod (14) located in the anti-drop housing (13). The moving valve seat (31) is threaded to the upper end of the anti-drop rod (14), the lower end of the anti-drop rod (14) is connected to the screw rotor (12), and the anti-drop rod (14) is provided with an anti-drop gasket (17).

4. The oscillating pulse screw drill bit for improving shaft stress as described in claim 3, characterized in that: The lower end of the anti-drop rod (14) is threadedly connected to the screw rotor (12) via a connector (15). A second adjusting shim (16) is provided between the connector (15) and the anti-drop rod (14) to adjust the axial clearance between the moving valve assembly (3) and the stationary valve assembly (2).

5. The oscillating pulse screw drill bit for improving shaft stress as described in claim 1, characterized in that: The top of the static valve housing (21) is provided with a threaded hole, and the static valve flow channel (22) is located at the lower end of the static valve housing (21). A hydraulic enhancement and amplification cavity (26) is connected between the threaded hole and the static valve flow channel (22). The diameter of the hydraulic enhancement and amplification cavity (26) is larger than the diameter of the threaded hole and the static valve flow channel (22).

6. The oscillating pulse screw drill bit for improving shaft stress as described in claim 1, characterized in that: The axis of the static valve flow channel (22) is collinear with the axis of the static valve housing (21), and the axis of the moving valve flow channel (33) is offset away from the axis of the static valve flow channel (22). The distance between the axis of the moving valve flow channel (33) and the axis of the static valve flow channel (22) is 5-15mm.

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