A bidirectional air-tight threaded connection device for oil drilling

Abstract

The present invention relates to the technical field of casing threaded joints, and in particular to a bidirectional air-tight threaded connection device for oil drilling, comprising a box coupling and two pin couplings; further comprising a threaded structure and a locking assembly, wherein both ends of an inner wall of the box coupling and the outer walls of the ends of the two pin couplings are connected via the threaded structure, and a locking assembly is installed between the box coupling and the two pin couplings, wherein the locking assembly locks the relative positions of the box coupling and the two pin couplings; the locking assembly is used to lock the relative positions of the box coupling and the pin couplings, thereby avoiding sealing failure of the threaded structure and improving reliability.

Description

Technical Field

[0001] The invention relates to the technical field of casing threaded joints, in particular to a bidirectional air-tight threaded connection device used for oil drilling. Background Art

[0002] In the process of shale gasoline well exploitation, the ends of the drill pipe are usually sealed and connected through threaded connection devices such as casing. For example, the oil casing threaded joint proposed in the Chinese invention patent application with publication number CN118481545A includes a pipe body and a coupling, and the threaded part includes an external thread, the external thread teeth have a first bearing surface and a first guide surface, along the axis of the oil casing threaded joint, the first bearing surface and the first guide surface are respectively located on both sides of the external thread teeth, and the first guide surface is inclined relative to the axis of the oil casing threaded joint; the internal thread, the internal thread teeth have a second bearing surface and a second guide surface, along the axis of the oil casing threaded joint, the second bearing surface and the second guide surface are respectively located on both sides of the internal thread teeth, and the second guide surface is inclined relative to the axis of the oil casing threaded joint; wherein the first bearing surface and the second bearing surface are interference fit, and at least part of the first guide surface and at least part of the second guide surface are interference fit; the problem that the oil casing threaded joint is prone to high stress concentration, resulting in poor fatigue resistance and high processing difficulty is solved.

[0003] When drilling for oil with a drill pipe, the threaded connection device is more protruding than the drill pipe, making it more susceptible to external impact, causing the outer hoop box and the male buckle tube of the threaded connection device to loosen easily, resulting in sealing failure. Summary of the invention

[0004] To solve the above technical problems, the present invention provides a bidirectional air-tight threaded connection device for oil drilling, which uses a locking assembly to lock the relative positions of a box coupling and a pin coupling, thereby avoiding sealing failure of the threaded structure and improving reliability.

[0005] A bidirectional air-tight threaded connection device for oil drilling of the present invention comprises a box coupling and two pin couplings; further comprising a threaded structure and a locking assembly, wherein the two ends of an inner wall of the box coupling and the outer walls of the ends of the two pin couplings are connected via a threaded structure, and a locking assembly is installed between the box coupling and the two pin couplings, and the locking assembly locks the relative positions of the box coupling and the two pin couplings; the two ends of the box coupling are respectively sealed and connected to the ends of the two pin couplings via a threaded structure, and the connection between the box coupling and the two pin couplings has good sealing performance. After the connection between the box coupling and the two pin couplings is completed, the relative positions of the box coupling and the two pin couplings are locked via the locking assembly, so as to avoid accidental loosening of the box coupling due to external force during oil drilling, resulting in failure of the sealing of the threaded structure, thereby improving reliability.

[0006] Preferably, the locking assembly includes two annular grooves, two half-tube buckles, four half-ring bosses and four bolts. The outer walls of the two male buckle couplings are provided with annular grooves. The bottoms of the two annular grooves are regular polygons. The outer wall cross-section of the female buckle coupling is a regular polygon. The middle inner walls of the two half-tube buckles are provided with a plurality of planes matching the outer wall of the female buckle coupling. Both ends of the two half-tube buckles are provided with half-ring bosses. The four half-ring bosses are respectively matched with the two annular grooves. The inner walls of the two half-ring bosses are provided with a plurality of planes matching the bottoms of the two annular grooves. The two half-tube buckles are buckled together to form a tubular shape. The two half-tube buckles are screwed together by four bolts. Tighten; after the box coupling and the two male couplings are connected by a threaded structure, the two half-tube couplings are fastened on the box coupling, and the multiple planes of the inner walls of the two half-tube couplings are aligned and contacted with the outer wall planes of the box coupling, and the four semi-ring bosses are respectively clamped in the two annular grooves, and the multiple planes of the four semi-ring bosses are aligned and contacted with the bottom planes of the two annular grooves. The two half-tube couplings are screwed and fastened by four bolts, so that the two half-tube couplings and the four semi-ring bosses lock the relative positions of the box coupling and the two male couplings, avoiding loosening of the box coupling relative to the two male couplings, avoiding sealing failure, and having high reliability.

[0007] Preferably, the locking assembly includes two annular grooves II, four limiting grooves, four arm rods, four semi-annular buckles and four bolts II. The outer walls of the two male buckle couplings are each provided with annular grooves II, the bottoms of the two annular grooves II are regular polygons, four limiting grooves are relatively arranged on both sides of the outer wall of the female buckle coupling, the inner ends of the four arm rods are respectively rotatably mounted on the outer wall of the female buckle coupling, the four arm rods are respectively clamped in the four limiting grooves, semi-annular buckles are respectively installed on the outer ends of the four arm rods, the four semi-annular buckles are respectively matched with the two annular grooves II, the inner walls of the four semi-annular buckles are respectively provided with multiple planes matching the bottoms of the two annular grooves II, and the four semi-annular buckles are connected through four Two bolts are used to screw and tighten them; after the female buckle coupling and the two male buckle couplings are connected by a threaded structure, the four arm rods are placed flat in the four limit grooves, so that the four limit grooves limit the four arm rods respectively, and the four semi-annular buckles are respectively clamped into the two annular grooves two, and the multiple planes of the inner walls of the four semi-annular buckles are respectively aligned and contacted with the multiple planes at the bottom of the two annular grooves two, and the four semi-annular buckles are screwed and tightened using four bolts two, so that the two annular grooves two and the four semi-annular buckles lock the relative positions of the female buckle coupling and the two male buckle couplings, avoiding loosening of the female buckle coupling relative to the two male buckle couplings, avoiding sealing failure, and having high reliability.

[0008] Preferably, the locking assembly includes two longitudinal sliding grooves 1, a sliding sleeve 1, a plurality of elastic hooks, a sliding sleeve 2, an annular protrusion and a push ring. The longitudinal sliding grooves 1 are arranged on the outer walls of the two male buckle couplings. The sliding sleeve 1 and the sliding sleeve 2 are respectively slidably mounted on the outer walls of the two male buckle couplings. The outer ends of the sliding sleeve 1 and the sliding sleeve 2 are respectively slidably connected with the two longitudinal sliding grooves 1. The outer wall of the female buckle coupling is circumferentially provided with a plurality of longitudinal sliding grooves 2. The inner walls of the sliding sleeve 1 and the sliding sleeve 2 are circumferentially provided with a plurality of longitudinal sliding strips matching the longitudinal sliding grooves 2. The inner end of the sliding sleeve 1 is circumferentially provided with a plurality of elastic hooks. The inner end of the sliding sleeve 2 is provided with an annular protrusion matching the plurality of elastic hooks. The push ring is slidably mounted on the sliding sleeve 2. A wedge-shaped surface is arranged on the outer end of the push ring, and the wedge-shaped surface guides and pushes the plurality of elastic hooks outward. After the female buckle coupling and the two male buckle couplings are connected by a threaded structure, the sliding sleeve When the two male buckles are unlocked, the first and second slide sleeves are pushed toward the female buckle coupling, so that the multiple longitudinal sliding strips of the first and second slide sleeves are respectively inserted into the multiple longitudinal sliding grooves of the female buckle coupling, and the multiple elastic hooks are hooked on the annular protrusions, so that the first and second slide sleeves lock the relative positions of the female buckle coupling and the two male buckle couplings, avoiding the female buckle coupling from loosening relative to the two male buckle couplings, avoiding sealing failure, and having high reliability. When it is necessary to loosen the first and second slide sleeves, the push ring is pushed toward the multiple elastic hooks, so that the wedge-shaped surface of the push ring guides and pushes the multiple elastic hooks outward, so that the multiple elastic hooks are disengaged from the annular protrusions, and the first and second slide sleeves are pushed outward onto the two male buckle couplings. At this time, the first and second slide sleeves contact the locking of the female buckle coupling and the two male buckle couplings, and can loosen the female buckle coupling and the two male buckle couplings, thereby improving the convenience of operation.

[0009] Preferably, the thread structure includes a first female thread, a first torque shoulder A, a second female thread, a thread backing groove, a first sealing cone surface A, a second sealing shoulder A, a first male thread, a first torque shoulder B, a second male thread, a backing outer cylindrical surface, a first sealing cone surface B and a second sealing shoulder B. The inner wall of the female coupling is provided with the first female thread, the first torque shoulder A, the second female thread, the thread backing groove, the first sealing cone surface A and the second sealing shoulder A in sequence from the middle of the left end, and the outer wall of the male coupling is provided with the first male thread, the first torque shoulder B, the second male thread, the backing outer cylindrical surface, the first sealing cone surface B and the second sealing shoulder B in sequence from the middle to the right end; the first female thread and the first male The buckle threads are threadedly matched, the first torque shoulder A and the first torque shoulder B are interference fit, the second female buckle thread and the second male buckle thread are threadedly matched, the first sealing cone surface A and the first sealing cone surface B are interference fit, and the second sealing shoulder A and the second sealing shoulder B are interference fit; the male buckle coupling and the female buckle coupling are threadedly connected with the second female buckle thread and the second male buckle thread through the first female buckle thread and the first torque shoulder A. After the male buckle coupling and the female buckle coupling are tightened, the first torque shoulder B and the first torque shoulder A, the first sealing cone surface B and the first sealing cone surface A, and the second sealing shoulder B and the second sealing shoulder A are pressed against each other and interference fit. The double-thread double-shoulder design increases the overall torsional load resistance of the device.

[0010] Preferably, it also includes a sealing copper sleeve, and a 1-2 mm deep groove is provided at the first sealing cone surface A and the second sealing shoulder A of the female coupling, and a sealing copper sleeve matching therewith is inlaid, and the thickness of the sealing copper sleeve is 2-3 mm; when the male coupling and the female coupling are tightened, the sealing copper sleeve is squeezed by the first sealing cone surface B and the second sealing shoulder B, so that the sealing copper sleeve is plastically deformed, and the sealing copper sleeve completely fits the sealing surfaces of the female coupling and the male coupling to form a permanent metal seal, which prevents external fluid from penetrating and makes up for the shortcomings of high hardness of the joint material and insufficient processing finish; at the same time, the sealing copper sleeve is resistant to high temperature and can maintain high sealing ability for a long time.

[0011] Preferably, the technical parameters of the first female thread and the first male thread, the second female thread and the second male thread are: pitch L is 5.8 mm, taper is 1:16, guide surface angle is 45°, and the angle between the bearing surface and the axis is 90°; by optimizing the thread tooth profile and adopting a 45° thread guide surface, the joint is not prone to cross-threading and the threading speed is increased; a 90° thread bearing surface is adopted to increase the bearing capacity when the female coupling and the male coupling are connected.

[0012] Preferably, the first torque shoulder A and the first torque shoulder B are both set to 90°.

[0013] Preferably, the first sealing cone surface B has an inclination angle of 20-21° with respect to the first sealing cone surface A, and the length is 7-8 mm.

[0014] Preferably, the inner wall of the right end surface of the male buckle coupling is provided with a reverse inclination angle of 10°, and a rounded transition is provided at the beginning of the reverse inclination angle.

[0015] Compared with the prior art, the present invention has the following beneficial effects: the two ends of the box coupling are respectively sealed and connected to the ends of the two pin couplings through a threaded structure, the connection between the box coupling and the two pin couplings has good sealing performance, and after the box coupling and the two pin couplings are connected, the relative positions of the box coupling and the two pin couplings are locked by a locking assembly, thereby preventing the box coupling from being accidentally loosened by external force during oil drilling, resulting in failure of the threaded structure seal, and improving reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of the structure of the decomposed state of embodiment 2 of the present invention;

[0017] Figure 2 is an axonometric schematic diagram of embodiment 2 of the present invention;

[0018] Figure 3 is a schematic diagram of the axonometric structure of embodiment 3 of the present invention;

[0019] Figure 4 is an axonometric schematic diagram of embodiment 4 of the present invention;

[0020] Figure 5 is a schematic structural diagram of a decomposed state of Example 4 of the present invention;

[0021] Figure 6 is a front cross-sectional structural schematic diagram of embodiment 4 of the present invention;

[0022] Figure 7 It is a structural schematic diagram of the mating state of the thread structure of the present invention;

[0023] Figure 8 It is a partial schematic diagram of the exploded state of the thread structure of the present invention;

[0024] Fig. 9 yes Figure 8 A schematic diagram of the local enlarged structure at point A in the middle;

[0025] Fig.10 yes Figure 8 A schematic diagram of the local enlarged structure at B in the middle;

[0026] Fig.11 It is an enlarged schematic diagram of the tooth shape of the thread structure.

[0027] Markings in the accompanying drawings: 1. female buckle coupling; 2. male buckle coupling; 3. annular groove 1; 4. half-tube buckle; 5. semi-annular boss; 6. bolt 1; 7. annular groove 2; 8. limit groove; 9. arm; 10. semi-annular buckle; 11. bolt 2; 12. longitudinal sliding groove 1; 13. sleeve 1; 14. elastic hook; 15. sleeve 2; 16. annular protrusion; 17. push ring; 18. first female buckle thread; 19. first torque shoulder A; 20. second female buckle thread; 21. thread backing groove; 22. first sealing cone surface A; 23. second sealing shoulder A; 24. first male buckle thread; 25. first torque shoulder B; 26. second male buckle thread; 27. backing outer cylindrical surface; 28. first sealing cone surface B; 29. ​​second sealing shoulder B; 30. sealing copper sleeve; 31. reverse inclination angle. DETAILED DESCRIPTION

[0028] In order to facilitate understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive. Example 1

[0029] like Figures 7 to 11As shown, a bidirectional airtight threaded connection device for oil drilling and production comprises a box coupling 1 and two pin couplings 2; further comprising a thread structure and a locking assembly, wherein both ends of the inner wall of the box coupling 1 and the outer walls of the ends of the two pin couplings 2 are connected by a thread structure, and a locking assembly is installed between the box coupling 1 and the two pin couplings 2, and the locking assembly locks the relative positions of the box coupling 1 and the two pin couplings 2; the thread structure comprises a first box thread 18, a first torque shoulder A19, a second box thread 20, a thread backing groove 21, a first sealing cone surface A22, a second sealing shoulder A23, a first The inner wall of the box coupling 1 is provided with the first box thread 18, the first torque shoulder A19, the second box thread 20, the thread backing groove 21, the first sealing cone surface A22 and the second sealing shoulder A23 in sequence from the middle of the left end, and the outer wall of the box coupling 2 is provided with the first box thread 24, the first torque shoulder B25, the second box thread 26, the backing outer cylindrical surface 27, the first sealing cone surface B28 and the second sealing shoulder A23 in sequence from the middle to the right end. shoulder B29; the first female thread 18 and the first male thread 24 are threadedly matched, the first torque shoulder A19 and the first torque shoulder B25 are interference matched, the second female thread 20 and the second male thread 26 are threadedly matched, the first sealing cone surface A22 and the first sealing cone surface B28 are interference matched, and the second sealing shoulder A23 and the second sealing shoulder B29 are interference matched; it also includes a sealing copper sleeve 30, and the first sealing cone surface A22 and the second sealing shoulder A23 of the female coupling 1 are provided with a groove with a depth of 1 to 2 mm, and a sealing copper sleeve 30 matching therewith is inlaid, and a sealing The thickness of the sealing copper sleeve 30 is 2~3mm; the technical parameters of the first female thread 18 and the first male thread 24, the second female thread 20 and the second male thread 26 are as follows: the pitch L is 5.8mm, the taper is 1:16, the guide surface angle is 45°, and the angle between the bearing surface and the axis is 90°; the first torque shoulder A19 and the first torque shoulder B25 are both set to 90°; the inclination angle of the first sealing cone surface B28 and the first sealing cone surface A22 is 20~21°, and the length is 7~8mm; the inner wall of the right end face of the male coupling 2 is provided with a reverse inclination angle 31 of 10°, and a rounded transition is provided at the starting point of the reverse inclination angle 31.

[0030] The male buckle coupling 2 and the female buckle coupling 1 are threadedly connected through the first female buckle thread 18 and the first torque shoulder A19 with the second female buckle thread 20 and the second male buckle thread 26. After the male buckle coupling 2 and the female buckle coupling 1 are tightened, the first torque shoulder B25 and the first torque shoulder A19, the second sealing shoulder B29 and the second sealing shoulder A23 are pressed against each other in an interference fit. The double-thread double-shoulder design increases the overall torsional load capacity of the device. When the male buckle coupling 2 and the female buckle coupling 1 are tightened, the first sealing cone surface B28 and the second sealing shoulder B29 squeeze the sealing copper sleeve 30, causing the sealing copper sleeve 30 to produce plastic deformation, and the sealing copper sleeve 30 completely fits the female buckle coupling 1 and the male buckle coupling The sealing surface of the clamp 2 forms a permanent metal seal to prevent external fluid from penetrating, which makes up for the high hardness of the joint material and the insufficient processing finish; at the same time, the sealing copper sleeve 30 is resistant to high temperature and can maintain high sealing ability for a long time. By optimizing the thread tooth shape and adopting a 45° thread guide surface, the joint is not easy to be wrongly threaded, which increases the threading speed; the 90° thread bearing surface is adopted to increase the bearing capacity when the box clamp 1 and the pin clamp 2 are connected; after the box clamp 1 and the two pin clamps 2 are connected, the relative position of the box clamp 1 and the two pin clamps 2 is locked by the locking assembly to avoid accidental loosening of the box clamp 1 by external force during oil drilling, resulting in failure of the thread structure seal. Example 2

[0031] like Figure 1 and Figure 2 As shown, on the basis of Example 1, the locking assembly includes two annular grooves 3, two half-tube buckles 4, four semi-ring bosses 5 and four bolts 6, annular grooves 3 are arranged on the outer walls of the two male buckle couplings 2, the bottoms of the two annular grooves 3 are regular polygons, the outer wall cross-section of the female buckle coupling 1 is a regular polygon, the middle inner walls of the two half-tube buckles 4 are provided with a plurality of planes matching the outer wall of the female buckle coupling 1, semi-ring bosses 5 are arranged at both ends of the two half-tube buckles 4, the four semi-ring bosses 5 are respectively matched with the two annular grooves 3, the inner walls of the two semi-ring bosses 5 are provided with a plurality of planes matching the bottoms of the two annular grooves 3, the two half-tube buckles 4 are buckled together to form a tubular shape, and the two half-tube buckles 4 are screwed and fastened by four bolts 6.

[0032] After the female coupling 1 and the two male couplings 2 are connected by a threaded structure, the two half-tube couplings 4 are buckled onto the female coupling 1, and multiple planes of the inner walls of the two half-tube couplings 4 are aligned and contacted with the outer wall plane of the female coupling 1, and the four semi-ring bosses 5 are respectively clamped in the two annular grooves 3, and multiple planes of the four semi-ring bosses 5 are aligned and contacted with the bottom planes of the two annular grooves 3. Four bolts 6 screw the two half-tube couplings 4 together to tighten them, so that the two half-tube couplings 4 and the four semi-ring bosses 5 lock the relative positions of the female coupling 1 and the two male couplings 2, avoiding loosening of the female coupling 1 relative to the two male couplings 2 and sealing failure. Example 3

[0033] like Figure 3 As shown, on the basis of Example 1, the locking assembly includes two annular grooves 27, four limiting grooves 8, four arm rods 9, four semi-annular buckles 10 and four bolts 21, the outer walls of the two male buckle couplings 2 are provided with annular grooves 27, the bottoms of the two annular grooves 27 are regular polygons, four limiting grooves 8 are relatively provided on both sides of the outer wall of the female buckle coupling 1, the inner ends of the four arm rods 9 are respectively rotatably installed on the outer wall of the female buckle coupling 1, the four arm rods 9 are respectively clamped in the four limiting grooves 8, and semi-annular buckles 10 are installed on the outer ends of the four arm rods 9, the four semi-annular buckles 10 are respectively matched with the two annular grooves 27, the inner walls of the four semi-annular buckles 10 are respectively provided with multiple planes matching the bottoms of the two annular grooves 27, and the four semi-annular buckles 10 are screwed and fastened by four bolts 21.

[0034] After the female buckle coupling 1 and the two male buckle couplings 2 are connected by a threaded structure, the four arm rods 9 are placed flat in the four limit grooves 8, so that the four limit grooves 8 limit the four arm rods 9 respectively, and the four semi-annular buckles 10 are respectively clamped into the two annular grooves 7, and the multiple planes of the inner walls of the four semi-annular buckles 10 are aligned and contacted with the multiple planes at the bottom of the two annular grooves 7 respectively, and the four semi-annular buckles 10 are screwed and tightened using four bolts 2 11, so that the two annular grooves 7 and the four semi-annular buckles 10 lock the relative positions of the female buckle coupling 1 and the two male buckle couplings 2, avoiding loosening of the female buckle coupling 1 relative to the two male buckle couplings 2, and avoiding sealing failure. Example 4

[0035] like Figures 4 to 6 As shown, on the basis of Example 1, the locking assembly includes two longitudinal sliding grooves 12, a sliding sleeve 13, a plurality of elastic hooks 14, a sliding sleeve 2 15, an annular protrusion 16 and a push ring 17. The longitudinal sliding grooves 12 are arranged on the outer walls of the two male buckle couplings 2, the sliding sleeve 13 and the sliding sleeve 2 15 are respectively slidably mounted on the outer walls of the two male buckle couplings 2, and the outer ends of the sliding sleeve 13 and the sliding sleeve 2 15 are respectively slidably connected with the two longitudinal sliding grooves 12, a plurality of longitudinal sliding grooves 2 are arranged on the circumference of the outer wall of the female buckle coupling 1, a plurality of longitudinal sliding strips matching the longitudinal sliding grooves 2 are arranged on the circumference of the inner walls of the sliding sleeve 13 and the sliding sleeve 2 15, a plurality of elastic hooks 14 are arranged on the circumference of the inner end of the sliding sleeve 13, an annular protrusion 16 matching the plurality of elastic hooks 14 is arranged on the inner end of the sliding sleeve 2 15, and the push ring 17 is slidably mounted on the sliding sleeve 2 15, and a wedge surface is arranged on the outer end of the push ring 17, and the wedge surface guides and pushes the plurality of elastic hooks 14 outward.

[0036] After the female buckle coupling 1 and the two male buckle couplings 2 are connected by the threaded structure, the sliding sleeve 13 and the sliding sleeve 2 15 are pushed toward the female buckle coupling 1, so that the multiple longitudinal slides of the sliding sleeve 13 and the sliding sleeve 2 15 are respectively inserted into the multiple longitudinal slide grooves 2 of the female buckle coupling 1, and the multiple elastic hooks 14 are hooked on the annular protrusions 16, so that the sliding sleeve 13 and the sliding sleeve 2 15 lock the relative positions of the female buckle coupling 1 and the two male buckle couplings 2, so as to prevent the female buckle coupling 1 from loosening relative to the two male buckle couplings 2 and avoid sealing Failure. When it is necessary to loosen the sliding sleeve 13 and the sliding sleeve 2 15, push the push ring 17 toward the multiple elastic hooks 14, so that the wedge surface of the push ring 17 guides and pushes the multiple elastic hooks 14 outward, so that the multiple elastic hooks 14 are disengaged from the annular protrusion 16. At this time, push the sliding sleeve 13 and the sliding sleeve 2 15 outward onto the two male buckle couplings 2. At this time, the sliding sleeve 13 and the sliding sleeve 2 15 contact the locking of the female buckle coupling 1 and the two male buckle couplings 2, and the female buckle coupling 1 and the two male buckle couplings 2 can be loosened.

[0037] like Figures 1 to 11 As shown, a bidirectional airtight threaded connection device for oil drilling of the present invention, when working, firstly, the male coupling 2 and the female coupling 1 are threadedly connected with the second female thread 20 and the second male thread 26 through the first female thread 18 and the first torque shoulder A19, and then when the male coupling 2 and the female coupling 1 are tightened, the first torque shoulder B25 and the first torque shoulder A19 are pressed against each other with interference fit, and then the first sealing cone surface B28 and the second sealing shoulder B29 squeeze the sealing copper sleeve 30 onto the first sealing cone surface A22 and the second sealing shoulder A23, so that the sealing copper sleeve 30 is plastically deformed, and the sealing copper sleeve 30 completely fits the sealing surface of the female coupling 1 and the male coupling 2 to form a permanent metal seal, and finally, after the female coupling 1 and the two male couplings 2 are connected, the relative positions of the female coupling 1 and the two male couplings 2 are locked by the locking assembly to prevent the female coupling 1 from being accidentally loosened by external force during oil drilling.

[0038] The main functions achieved by the present invention are:

[0039] 1. Use a locking assembly to lock the relative positions of the box coupling 1 and the pin coupling 2 to avoid sealing failure of the threaded structure and improve reliability;

[0040] 2. The double-thread double-shoulder design increases the overall torsional load capacity of the device;

[0041] 3. A sealing copper sleeve 30 is used to form a permanent metal seal. The sealing copper sleeve 30 is resistant to high temperatures and can maintain high sealing ability for a long time;

[0042] 4. The 90° thread bearing surface is adopted to increase the bearing capacity when the box coupling 1 and the pin coupling 2 are connected;

[0043] 5. The thread profile with a 45° guide angle makes it less likely for the joint to be cross-threaded and increases the threading speed.

[0044] The installation method, connection method or setting method of a bidirectional air-tight threaded connection device for oil drilling of the present invention are all common mechanical methods, and can be implemented as long as they can achieve their beneficial effects; the female buckle coupling 1, male buckle coupling 2, bolt one 6, bolt two 11, elastic hook 14, and sealing copper sleeve 30 of the bidirectional air-tight threaded connection device for oil drilling of the present invention are purchased on the market, and technicians in the industry only need to install and operate them according to the accompanying instruction manual, without the need for creative labor by technicians in this field.

[0045] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A bidirectional airtight threaded connection device for oil drilling, comprising a female coupling (1) and two male couplings (2); characterized in that: It also includes a threaded structure and a locking assembly, wherein the two ends of the inner wall of the box coupling (1) and the outer walls of the ends of the two pin couplings (2) are connected via the threaded structure, and a locking assembly is installed between the box coupling (1) and the two pin couplings (2), wherein the locking assembly locks the relative positions of the box coupling (1) and the two pin couplings (2); The locking assembly comprises two annular grooves (7), four limiting grooves (8), four arm rods (9), four semi-annular buckles (10) and four bolts (11). The outer walls of the two male buckle couplings (2) are each provided with annular grooves (7), the bottoms of the two annular grooves (7) are regular polygons, four limiting grooves (8) are oppositely arranged on the outer wall of the female buckle coupling (1), the inner ends of the four arm rods (9) are respectively rotatably mounted on the outer wall of the female buckle coupling (1), the four arm rods (9) are respectively clamped in the four limiting grooves (8), the outer ends of the four arm rods (9) are each provided with semi-annular buckles (10), the four semi-annular buckles (10) are respectively matched with the two annular grooves (7), the inner walls of the four semi-annular buckles (10) are respectively provided with a plurality of planes matching with the bottoms of the two annular grooves (7), and the four semi-annular buckles (10) are screwed and fastened by four bolts (11).

2. A bidirectional airtight threaded connection device for oil drilling as claimed in claim 1, characterized in that: Another structural form of the locking assembly comprises two longitudinal slide grooves (12), a slide sleeve (13), a plurality of elastic hooks (14), a slide sleeve (15), an annular protrusion (16) and a push ring (17), the longitudinal slide grooves (12) are arranged on the outer walls of the two male buckle couplings (2), the slide sleeves (13) and the slide sleeves (15) are respectively slidably mounted on the outer walls of the two male buckle couplings (2), the outer ends of the slide sleeves (13) and the slide sleeves (15) are respectively slidably connected to the two longitudinal slide grooves (12), and the female buckle coupling (1 ) are provided with a plurality of longitudinal slide grooves 2 on the circumference of the outer wall, a plurality of longitudinal slide strips matching the longitudinal slide grooves 2 are provided on the circumference of the inner walls of the slide sleeve 1 (13) and the slide sleeve 2 (15), a plurality of elastic hooks (14) are provided on the circumference of the inner end of the slide sleeve 1 (13), an annular protrusion (16) matching the plurality of elastic hooks (14) is provided on the inner end of the slide sleeve 2 (15), a push ring (17) is slidably mounted on the slide sleeve 2 (15), a wedge-shaped surface is provided on the outer end of the push ring (17), and the wedge-shaped surface guides and pushes the plurality of elastic hooks (14) outward.

3. A bidirectional airtight threaded connection device for oil drilling as claimed in claim 1, characterized in that: The thread structure comprises a first female thread (18), a first torque shoulder A (19), a second female thread (20), a thread backing groove (21), a first sealing cone surface A (22), a second sealing shoulder A (23), a first male thread (24), a first torque shoulder B (25), a second male thread (26), a backing outer cylindrical surface (27), a first sealing cone surface B (28) and a second sealing shoulder B (29). The inner wall of the female coupling (1) is provided with the first female thread (18), the first torque shoulder A (19), the second female thread (20), the thread backing groove (21), the first sealing cone surface A (22) and the second sealing shoulder A (23) in sequence from the middle of the left end. The outer wall of the coupling (2) is provided with a first male thread (24), a first torque shoulder B (25), a second male thread (26), a backing outer cylindrical surface (27), a first sealing cone surface B (28) and a second sealing shoulder B (29) in sequence from the middle to the right end; the first female thread (18) and the first male thread (24) are threadedly matched, the first torque shoulder A (19) and the first torque shoulder B (25) are interference matched, the second female thread (20) and the second male thread (26) are threadedly matched, the first sealing cone surface A (22) and the first sealing cone surface B (28) are interference matched, and the second sealing shoulder A (23) and the second sealing shoulder B (29) are interference matched.

4. A bidirectional airtight threaded connection device for oil drilling as claimed in claim 3, characterized in that: It also comprises a sealing copper sleeve (30), wherein a groove with a depth of 1 to 2 mm is provided at the first sealing cone surface A (22) and the second sealing shoulder A (23) of the female buckle coupling (1), and a sealing copper sleeve (30) matching with the groove is inlaid therein, and the sealing copper sleeve (30) has a thickness of 2 to 3 mm.

5. A bidirectional airtight threaded connection device for oil drilling as claimed in claim 3, characterized in that: The technical parameters of the first female thread (18) and the first male thread (24), the second female thread (20) and the second male thread (26) are as follows: the pitch L is 5.8 mm, the taper is 1:16, the guide surface angle is 45°, and the angle between the bearing surface and the axis is 90°.

6. A bidirectional airtight threaded connection device for oil drilling as claimed in claim 3, characterized in that: The first torque shoulder A (19) and the first torque shoulder B (25) are both set at 90 degrees.

7. A bidirectional airtight threaded connection device for oil drilling as claimed in claim 3, characterized in that: The first sealing cone surface B (28) has an inclination angle of 20 to 21 degrees with respect to the first sealing cone surface A (22), and a length of 7 to 8 mm.

8. A bidirectional airtight threaded connection device for oil drilling as claimed in claim 3, characterized in that: The inner wall of the right end surface of the male buckle coupling (2) is provided with a reverse inclination angle (31) of 10°, and a rounded transition is provided at the start of the reverse inclination angle (31).

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