Connecting structure and connecting method for pile casing of full-slewing drilling machine

Abstract

The invention belongs to the technical field of pile casing connection, and discloses a pile casing connection structure and method of a full-slewing drilling machine, and the pile casing connection structure of the full-slewing drilling machine is arranged at a pile casing splicing end and comprises a connecting ring, a first holding tile, a second holding tile and a fastening structure used for locking the first holding tile and the second holding tile. By arranging the connecting rings, the connecting piles, the first holding tiles, the second holding tiles and the fastening structures, connection between the adjacent pile casings is achieved, the situation that abrasion directly occurs on the pile casings, and consequently the pile casings need to be integrally maintained or replaced is avoided, the axial overlap ratio, circumferential limiting and axis limiting are further guaranteed when the pile casings are connected, and the service life of the pile casings is prolonged. And stable and reliable guarantee is provided for the connection of the pile casing.

Description

Technical Field

[0001] The invention belongs to the technical field of casing connection, and in particular relates to a casing connection structure and a connection method for a full-rotation drilling rig. Background Art

[0002] Full-rotation drilling rigs are used in the fields of quicksand, karst landforms, interlocking pile construction, and pile removal and obstacle removal. Full-rotation drilling rigs are devices that use a power device to obtain strong downward pressure and rotational force to work. In order to ensure the quality of pile formation, eliminate mud pollution, and reduce the concrete filling coefficient, the full-rotation drilling rig will be connected to the casing to work. By connecting the casing to form a hole, piles can be formed and obstacles can be cleared from the casing, and, if Figure 1 As shown in FIG, the casing at the lower end is also equipped with a cutter head 2.

[0003] The existing connection method between casing and full-rotation drilling rig is often to directly pass through the upper and lower adjacent casings with multiple bolts, and then cooperate with nuts to fix the connection. The force is directly transmitted to the through hole of the casing through the bolts. Under the action of long-term load, the through hole on the casing for passing the bolts is worn, and the hole diameter becomes larger. The bolt cannot play the role of axial movement limit for the adjacent casing in the form of shaft hole cooperation. At this time, only the pressure applied by the nut forms static friction to limit the movement of the casing. The reliability of this restriction is low. Some other casings fix the axial position of the casing by means of locating pins and locating holes. However, similarly, under the action of long-term load, the size of the locating hole will also change, resulting in the axial position of the adjacent casing cannot be determined;

[0004] In addition, the deformation caused by wear occurs directly on the casing, which means that the entire casing needs to be directly repaired during maintenance. The maintenance workload is large, the cycle is long, and the difficulty is high. If the maintenance cannot be carried out, the entire casing will be directly scrapped. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a casing connection structure and a connection method for a full-rotation drilling rig, which solves the problem in the prior art that the existing connection structure causes the casing to wear under the action of load, reduces the stability of the connection between the casings, and makes the later maintenance of the casing difficult.

[0006] In order to achieve the above technical objectives, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a casing connection structure for a fully rotary drilling rig, which is arranged at a casing splicing end and includes a connecting ring, a first holding tile, a second holding tile, and a fastening structure for locking the first holding tile and the second holding tile;

[0008] The casing is provided with an annular main body, an annular positioning section located at one side of the main body splicing end, the outer diameter of the positioning section is smaller than the outer diameter of the main body, the end surface of the main body is provided with a plurality of connecting piles, the connecting piles are located between the outer circumferential surface of the main body and the outer circumferential surface of the positioning section, the connecting piles are provided with a pile section, a locking section, and a plurality of circular rings distributed at intervals along the axial direction of the locking section, and a first bite space is formed between the circular rings;

[0009] The connecting ring limits the degree of freedom of misaligned rotation between adjacent casings in the circumferential direction, the inner ring of the connecting ring is adapted to the outer ring of the positioning section, the connecting ring connects two sections of casings at the same time, the outer circumferential surface of the connecting ring is provided with annularly distributed depressions, the connecting ring is provided with an upper plug hole and a lower plug hole connected to the depressions in a direction parallel to the axis, the upper plug hole cooperates with the connecting pile of the casing located above, the lower plug hole cooperates with the connecting pile of the casing located below, and the length of the connecting pile is greater than the depth of the upper plug hole and the lower plug hole;

[0010] The first and second bushings limit the degree of freedom of the adjacent casings to be separated and combined in the axial direction. The first and second bushings are simultaneously engaged with the locking sections of the adjacent casings. The first and second bushings are both semi-annular. The inner walls of the first and second bushings are provided with two rows of semi-annular first bite teeth in the axial direction, one row above the other. In each row, a semi-meshing space is formed between the first bite teeth.

[0011] The first teeth at the same height position of the inner walls of the first and second bearing tiles match together to form a complete tooth that fits the first engagement space, and the semi-engaging spaces at the same height position of the inner walls of the first and second bearing tiles match together to form a complete engagement space that fits the circular ring.

[0012] In order to maintain the overlap of the axes of adjacent casings, the present invention provides a connecting ring, which is used to insert the positioning sections of adjacent casings, so that the axial positions of the adjacent casings are constrained by the connecting ring. The overlap of the axes between the casings directly determines the verticality of the hole. The casing is provided with a main body and a positioning section. Since the outer diameter of the positioning section is smaller than the outer diameter of the main body, the part of the main body that is larger than the positioning section in radial direction plays a role of limiting and blocking. When the positioning section is inserted into the connecting ring, the main body interferes with the connecting ring, and the depth of the matching between the casing and the connecting ring is determined.

[0013] In order to limit the degree of freedom of misaligned rotation between adjacent casings in the circumferential direction, the present invention provides a connection ring and a plurality of connection piles located on the end surface of the main body. After the casing is inserted into the connection ring, the connection piles on the main body of the adjacent casing are also respectively inserted into the upper plug hole and the lower plug hole of the connection ring. When the upper casing wants to rotate about the axis, the connection pile of the upper casing applies a force to the connection ring, and the force causes the connection ring to rotate in the same direction, and the lower plug hole in the connection ring drives the lower casing to follow the rotation. Therefore, the structure realizes power transmission while ensuring that the adjacent casings can rotate synchronously without misalignment in the circumferential direction.

[0014] In order to limit the freedom of adjacent casings to separate and combine axially, the present invention provides a first holding shoe and a second holding shoe. When the first holding shoe and the second holding shoe are locked with each other under the action of the fastening structure, they act as connecting pieces, wrapping adjacent connecting piles to achieve axial connection of adjacent casings. The complete teeth adapted to the first engaging space enter the first engaging space between the circular rings, and the circular rings enter the complete engaging space formed by the combination of the semi-engaging spaces. The complete teeth and the circular rings are interlaced to achieve transmission of axial force. Since there are multiple complete teeth and circular rings, and the complete teeth and the circular rings are in surface contact, there are more force transmission points, and the risk of wear and crushing of a single contact surface is shared. Therefore, the service life and stability of the connection structure can be improved. In addition, in order to further improve the service life of the connecting piles on the casing, materials with lower hardness can be selected to make them. The first and second bearing tiles are provided, and the hardness of the first and second bearing tiles is ensured to be lower than that of the connecting pile, so that most of the wear occurs on the first and second bearing tiles which are easy to replace, thereby reducing the wear of the connecting pile. In addition, it should be added that the role of the annularly distributed depressions on the circumference of the connecting ring is to provide installation space and facilitate direct installation from the outside. During installation, the first bearing tile is first matched with the connecting pile, and then the first bearing tile is rotated about the connecting pile, and the first bearing tile is rotated to the inside, leaving enough space for placing the second bearing tile. When the second bearing tile is also matched with the connecting pile, the first bearing tile and the second bearing tile are locked together by the fastening structure to prevent the two from separating. The role of the length of the connecting pile being greater than the depth of the upper plug hole and the lower plug hole is to ensure that the locking section is exposed in the depression, so that there is enough length to match the first and second bearing tiles.

[0015] The present invention realizes the connection between adjacent casings by arranging a connecting ring, a connecting pile, a first holding shoe, a second holding shoe and a fastening structure, thereby avoiding wear directly occurring on the casing, which would cause the casing to need overall repair or replacement, and further ensures the axial overlap, circumferential limit and axial limit when the casing is connected, providing stable and reliable protection for the connection of the casing.

[0016] In a second aspect, the present invention provides a method for connecting a casing of a fully rotary drilling rig, which uses the above-mentioned casing connection structure of a fully rotary drilling rig to connect the casing.

[0017] Beneficial effects of the present invention: The present invention realizes the connection between adjacent casings by arranging a connecting ring, a connecting pile, a first holding tile, a second holding tile and a fastening structure, thereby avoiding wear directly occurring on the casing, which causes the casing to need overall repair or replacement, and further ensures the axial overlap, circumferential limit and axial limit when the casing is connected, providing stable and reliable guarantee for the connection of the casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention can be further illustrated by the non-limiting examples given in the accompanying drawings;

[0019] Figure 1 It is a structural schematic diagram of an embodiment of the present invention;

[0020] Figure 2 For the embodiment of the present invention Figure 1 A partial enlarged view of the middle A;

[0021] Figure 3 For the embodiment of the present invention Figure 1 Schematic diagram of the structure of the middle casing;

[0022] Figure 4 For the embodiment of the present invention Figure 3 A partial enlarged view of point B in the middle;

[0023] Figure 5 For the embodiment of the present invention Figure 4 Schematic diagram of the structure of the connecting pile;

[0024] Figure 6 For the embodiment of the present invention Figure 2 Schematic diagram of the structure of the middle connecting ring;

[0025] Figure 7 For the embodiment of the present invention Figure 2 The structural diagram of the second holding tile in the middle;

[0026] Figure 8 For the embodiment of the present invention Figure 2 The structural diagram of the first holding tile in the middle;

[0027] Fig. 9 For the embodiment of the present invention Figure 2 Schematic diagram of the structure of the stud bolt;

[0028] Fig.10 It is an exploded view of the first holding tile, the second holding tile, the connecting pile, the stud bolt and the locking nut when they are matched in the embodiment of the present invention;

[0029] The main component symbols are described as follows:

[0030] 1. casing; 11. main body; 12. positioning section; 13. connecting pile; 131. pile section; 132. locking section; 133. circular ring; 134. first engaging space;

[0031] 2. Blade head;

[0032] 4. connecting ring; 41. depression; 42. upper plug hole; 43. lower plug hole;

[0033] 5. Second holding tile; 51. Second area; 52. Through hole;

[0034] 6. First holding shoe; 61. First area; 62. Internal thread ring; 63. First biting tooth; 64. Semi-biting space;

[0035] 7. Stud bolt; 71. Fine thread section; 72. Coarse thread section;

[0036] 8. Locking nut;

[0037] 9. Sealing ring. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is described in detail below in conjunction with specific embodiments and their accompanying drawings. The embodiments recorded herein are specific embodiments of the present invention, which are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be construed as limitations on the embodiments of the present invention and the scope of protection of the present invention. In addition to the embodiments recorded herein, those skilled in the art can also adopt other obvious technical solutions based on the contents disclosed in the claims of this application and its specification, including technical solutions that adopt any obvious replacements and modifications to the embodiments recorded herein.

[0039] Example 1

[0040] like Figure 1-8 As shown, this embodiment provides a casing connection structure for a full-rotation drilling rig, which is arranged at the splicing end of the casing 1, and includes a connecting ring 4, a first holding tile 6, a second holding tile 5, and a fastening structure for locking the first holding tile 6 and the second holding tile 5;

[0041] The casing 1 is provided with an annular main body 11, an annular positioning section 12 located at one side of the splicing end of the main body 11, the outer diameter of the positioning section 12 is smaller than the outer diameter of the main body 11, and a plurality of connecting piles 13 are provided on the end surface of the main body 11, the connecting piles 13 are located between the outer circumferential surface of the main body 11 and the outer circumferential surface of the positioning section 12, and the connecting piles 13 are provided with a pile section 131, a locking section 132, and a plurality of circular rings 133 distributed axially at intervals along the locking section 132, and a first bite space 134 is formed between the circular rings 133;

[0042] The connecting ring 4 limits the degree of freedom of misaligned rotation between adjacent casings 1 in the circumferential direction. The inner ring of the connecting ring 4 is adapted to the outer ring of the positioning section 12. The connecting ring 4 connects two sections of casings 1 at the same time. The outer circumferential surface of the connecting ring 4 is provided with annularly distributed recesses 41. The connecting ring 4 is provided with an upper plug hole 42 and a lower plug hole 43 connected to the recess 41 in a direction parallel to the axis. The upper plug hole 42 cooperates with the connecting pile 13 of the casing 1 located above, and the lower plug hole 43 cooperates with the connecting pile 13 of the casing 1 located below. The length of the connecting pile 13 is greater than the depth of the upper plug hole 42 and the lower plug hole 43.

[0043] The first bearing shoe 6 and the second bearing shoe 5 limit the degree of freedom of the adjacent casing 1 to be separated and combined in the axial direction. The first bearing shoe 6 and the second bearing shoe 5 are simultaneously engaged with the locking section 132 of the adjacent casing 1. The first bearing shoe 6 and the second bearing shoe 5 are both semi-annular. The inner walls of the first bearing shoe 6 and the second bearing shoe 5 are provided with two rows of semi-annular first bite teeth 63 in the axial direction, one row above and one row below. In each row, a semi-engaging space 64 is formed between the first bite teeth 63.

[0044] The first biting teeth 63 at the same height position on the inner walls of the first and second holding tiles 6, 5 match to form a complete biting tooth adapted to the first biting space 134, and the semi-biting spaces 64 at the same height position on the inner walls of the first and second holding tiles 6, 5 match to form a complete biting space adapted to the circular ring 133.

[0045] In this embodiment, in order to maintain the axial overlap of adjacent casings 1, a connecting ring 4 is provided. The connecting ring 4 is used to insert the positioning section 12 of the adjacent casing 1, so that the axial position of the adjacent casing 1 is constrained by the connecting ring 4. The axial overlap between the casings 1 directly determines the verticality of the hole. The casing 1 is provided with a main body 11 and a positioning section 12. Since the outer diameter of the positioning section 12 is smaller than the outer diameter of the main body 11, the part of the main body 11 that is larger than the positioning section 12 in radial direction plays a role of limiting and blocking. After the positioning section 12 is inserted into the connecting ring 4, the main body 11 interferes with the connecting ring 4, and the depth of the matching between the casing 1 and the connecting ring 4 is determined.

[0046] In terms of limiting the degree of freedom of misaligned rotation between adjacent casings 1 in the circumferential direction, a connecting ring 4 and a plurality of connecting piles 13 located on the end surface of the main body 11 are provided. After the casing 1 is inserted into the connecting ring 4, the connecting piles 13 on the main body 11 of the adjacent casing 1 are also respectively inserted into the upper plug hole 42 and the lower plug hole 43 of the connecting ring 4. When the upper casing 1 wants to rotate about the axis, the connecting pile 13 of the upper casing 1 applies a force to the connecting ring 4, which will cause the connecting ring 4 to rotate in the same direction, and the lower plug hole 43 in the connecting ring 4 will drive the lower casing 1 to follow the rotation. Therefore, the structure realizes power transmission while ensuring that the adjacent casings 1 can rotate synchronously without misalignment in the circumferential direction.

[0047] In order to limit the freedom of adjacent casings 1 to separate and combine axially, a first holding shoe 6 and a second holding shoe 5 are provided. When the first holding shoe 6 and the second holding shoe 5 are locked with each other under the action of the fastening structure, they act as connecting parts, wrapping the adjacent connecting piles 13, and realizing the axial connection of the adjacent casings 1. The complete biting teeth adapted to the first biting space 134 enter the first biting space 134 between the circular rings 133, and the circular rings 133 enter the complete biting space formed by the combination of the semi-biting spaces 64. The complete biting teeth and the circular rings 133 are interlaced with each other to realize the transmission of axial force. Since there are multiple complete biting teeth and circular rings 133, and there is surface contact between the complete biting teeth and the circular rings 133, there are more force transmission points, and the risk of wear and crushing of a single contact surface is shared, thereby improving the service life and stability of the connection structure. In addition, in order to further improve the service life of the connecting piles 13 on the casing 1, a material with lower hardness can be selected to make the first holding shoe. 6, the second holding tile 5, and ensure that the hardness of the first holding tile 6 and the second holding tile 5 is lower than the hardness of the connecting pile 13, so that most of the wear occurs on the first holding tile 6 and the second holding tile 5 which are easy to replace, reducing the wear of the connecting pile 13. In addition, it should be added that the role of the annular recesses 41 distributed around the connecting ring 4 is to provide installation space and facilitate direct installation from the outside. During installation, the first holding tile 6 is first matched with the connecting pile 13, and then the first holding tile 6 is rotated about the connecting pile 13, and the first holding tile 6 is rotated to the inside, leaving enough space for placing the second holding tile 5. When the second holding tile 5 is also matched with the connecting pile 13, the first holding tile 6 and the second holding tile 5 are locked together by the fastening structure to prevent the two from separating; the length of the connecting pile 13 is greater than the depth of the upper plug hole 42 and the lower plug hole 43, which plays a role in that the locking section 132 must be exposed in the recess 41, so that there is enough length to match the first holding tile 6 and the second holding tile 5.

[0048] The present invention realizes the connection between adjacent casings 1 by providing a connecting ring 4, a connecting pile 13, a first holding tile 6, a second holding tile 5 and a fastening structure, thereby avoiding wear directly occurring on the casing 1, which would cause the casing 1 to need overall repair or replacement, and further ensures the axial overlap, circumferential limit and axial limit when the casing 1 is connected, providing a stable and reliable guarantee for the connection of the casing 1.

[0049] Example 2

[0050] like Figure 2 As shown, this embodiment provides a fully rotary drilling rig casing connection structure, which differs from Embodiment 1 in that the length of the positioning section 12 is less than half the height of the connecting ring 4; a circle of annular sealing rings 9 are fixed to the inner wall of the connecting ring 4.

[0051] In this embodiment, since there is already a positioning base surface, that is, the main body 11 interferes with the connecting ring 4, the depth of the cooperation between the casing 1 and the connecting ring 4 is determined. Therefore, in order to avoid the positioning sections 12 of two adjacent casings 1 from interfering with each other, the length of the positioning section 12 is set to be less than half of the height of the connecting ring 4, and the space between the positioning sections 12 of the two adjacent casings 1 is filled and sealed by the sealing ring 9.

[0052] Example 3

[0053] like Figure 2 , 7 , 8, 9, and 10, this embodiment provides a casing connection structure for a full-rotation drill rig, which is different from Embodiment 1 in that the fastening structure includes a stud bolt 7 and a locking nut 8, one end of the stud bolt 7 is connected to the first bushing 6, and the other end of the stud bolt 7 is connected to the locking nut 8 after passing through the second bushing 5, and the locking nut 8 applies an extrusion force to the second bushing 5; a first area 61 is provided on the inner wall of the first bushing 6, and the first area 61 is located in a blank position between two rows of first teeth 63 on the inner wall of the first bushing 6; a second area 51 is provided on the inner wall of the second bushing 5, and the second area 51 is located in a blank position between two rows of first teeth 63 on the inner wall of the second bushing 5;

[0054] The first region 61 is provided with an internal thread ring 62, the interior of the internal thread ring 62 has threads matching the stud bolt 7;

[0055] The second area 51 is provided with through holes 52 corresponding to the number of the internal thread rings 62, and the diameter of the through holes 52 is larger than the diameter of the stud bolts 7;

[0056] Anti-loosening liquid is filled between the stud bolt 7 and the locking nut 8, and between the stud bolt 7 and the internal thread ring 62;

[0057] The stud bolt 7 is provided with a fine-thread segment 71 and a coarse-thread segment 72 . The fine-thread segment 71 is connected to the first holding shoe 6 , and the coarse-thread segment 72 is connected to the locking nut 8 .

[0058] In this embodiment, the fine thread section 71 of the stud bolt 7 is connected to the internal thread ring 62 of the first bearing bush 6, so as to achieve the fixation of the stud bolt 7 on the first bearing bush 6. After the coarse thread section 72 of the stud bolt 7 passes through the through hole 52, it cooperates with the locking nut 8, and the locking nut 8 applies an extrusion force to the second bearing bush 5, so as to achieve the locking of the first bearing bush 6 and the second bearing bush 5.

[0059] During disassembly, only the locking nut 8 needs to be loosened to separate the first bearing bush 6 and the second bearing bush 5, without removing the stud bolt 7. Therefore, the fine pitch segment 71 of the stud bolt 7 can be placed on the internal thread ring 62 for a long time. The length of the internal thread ring 62 is designed according to actual conditions. A longer internal thread ring 62 can provide more matching area with the fine pitch segment 71, thereby improving the stability of the connection. The anti-loosening liquid filled between the fine pitch segment 71 and the internal thread ring 62 helps prevent loosening and maintain the fixation of the stud bolt 7 on the first bearing bush 6. The fine pitch thread is used because it has good self-locking performance.

[0060] The coarse thread section 72 adopts a coarse thread and cooperates with the locking nut 8. The first reason is that it is easy to disassemble and install. Since the locking nut 8 needs to be disassembled and assembled according to construction needs, the coarse thread's easy disassembly and assembly feature is more suitable for this scenario. The second reason is that it can withstand greater torque and tension. When locking, it can effectively ensure the locking of the first holding tile 6 and the second holding tile 5. The diameter of the stud bolt 7 is smaller than the diameter of the through hole 52, which can avoid interference between the through hole 52 and the stud bolt 7, thereby improving the convenience of assembly.

[0061] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Any person skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A casing connection structure for a fully rotary drilling rig, arranged at the splicing end of the casing (1), Features: It comprises a connecting ring (4), a first holding tile (6), a second holding tile (5), and a fastening structure for locking the first holding tile (6) and the second holding tile (5); The casing (1) is provided with an annular main body (11), an annular positioning section (12) located at one side of the splicing end of the main body (11), the outer diameter of the positioning section (12) is smaller than the outer diameter of the main body (11), the end surface of the main body (11) is provided with a plurality of connecting piles (13), the connecting piles (13) are located between the outer circumferential surface of the main body (11) and the outer circumferential surface of the positioning section (12), the connecting piles (13) are provided with a pile section (131), a locking section (132), and a plurality of circular rings (133) distributed axially at intervals along the locking section (132), and a first engaging space (134) is formed between the circular rings (133); The connecting ring (4) limits the degree of freedom of misaligned rotation between adjacent casings (1) in the circumferential direction. The inner ring of the connecting ring (4) is adapted to the outer ring of the positioning section (12). The connecting ring (4) connects two sections of casing (1) at the same time. The outer circumferential surface of the connecting ring (4) is provided with annularly distributed depressions (41). The connecting ring (4) is provided with an upper plug hole (42) and a lower plug hole (43) connected to the depression (41) in a direction parallel to the axis. The upper plug hole (42) cooperates with the connecting pile (13) of the casing (1) located above, and the lower plug hole (43) cooperates with the connecting pile (13) of the casing (1) located below. The length of the connecting pile (13) is greater than the depth of the upper plug hole (42) and the lower plug hole (43). The first bearing shoe (6) and the second bearing shoe (5) limit the degree of freedom of the adjacent casing (1) to separate and combine in the axial direction. The first bearing shoe (6) and the second bearing shoe (5) are simultaneously engaged with the locking section (132) of the adjacent casing (1). The first bearing shoe (6) and the second bearing shoe (5) are both semi-annular. The inner walls of the first bearing shoe (6) and the second bearing shoe (5) are provided with two rows of semi-annular first bite teeth (63) one above the other along the axial direction. In each row, a semi-engaging space (64) is formed between the first bite teeth (63). The first bite teeth (63) at the same height position on the inner walls of the first embrace tile (6) and the second embrace tile (5) are matched to form a complete bite tooth adapted to the first bite space (134); the semi-bite space (64) at the same height position on the inner walls of the first embrace tile (6) and the second embrace tile (5) are matched to form a complete bite space adapted to the circular ring (133).

2. A casing connection structure for a fully rotary drilling rig according to claim 1, Features: The length of the positioning section (12) is less than half the height of the connecting ring (4).

3. A casing connection structure for a fully rotary drilling rig according to claim 2, Features: A sealing ring (9) arranged in an annular shape is fixed to the inner wall of the connecting ring (4).

4. The casing connection structure of a fully rotary drilling rig according to claim 1, Features: The fastening structure comprises a stud bolt (7) and a locking nut (8); one end of the stud bolt (7) is connected to the first bearing bush (6); the other end of the stud bolt (7) passes through the second bearing bush (5) and is connected to the locking nut (8); the locking nut (8) applies a squeezing force to the second bearing bush (5).

5. A casing connection structure for a fully rotary drilling rig according to claim 4, Features: The inner wall of the first holding tile (6) is provided with a first area (61), and the first area (61) is located in a blank position between two rows of first teeth (63) on the inner wall of the first holding tile (6); the inner wall of the second holding tile (5) is provided with a second area (51), and the second area (51) is located in a blank position between two rows of first teeth (63) on the inner wall of the second holding tile (5); The first region (61) is provided with an internal thread ring (62), the interior of the internal thread ring (62) having threads matching the stud bolt (7); The second area (51) is provided with through holes (52) corresponding to the number of the internal thread rings (62), and the diameter of the through holes (52) is larger than the diameter of the stud bolts (7).

6. A casing connection structure for a fully rotary drilling rig according to claim 4, Features: Anti-loosening liquid is filled between the stud bolt (7) and the locking nut (8), and between the stud bolt (7) and the internal threaded ring (62).

7. The casing connection structure of a full-rotation drilling rig according to claim 4, Features: The stud bolt (7) is provided with a fine-thread segment (71) and a coarse-thread segment (72); the fine-thread segment (71) is connected to the first bushing (6), and the coarse-thread segment (72) is connected to the locking nut (8).

8. A method for connecting casing of a full-rotation drilling rig. Features: The casing is connected by using a fully rotary drilling rig casing connection structure as described in any one of claims 1 to 7.

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