A directional drilling casing-while-drilling centralizer

Abstract

This invention discloses a center positioning device for the guide tube inside a directional drilling casing, relating to the technical field of directional drilling construction equipment. The device includes a fixed ring, a rotating ring, a single-point screw drive structure, an inner clamping centering structure, and an outer support positioning structure. The rotating ring is rotatably disposed inside the fixed ring, the inner clamping centering structure is disposed inside the rotating ring, and the outer support positioning structure is disposed on the fixed ring. The single-point screw drive structure is connected to both the fixed ring and the rotating ring and drives the rotating ring to rotate relative to the fixed ring. When the rotating ring rotates, the outer support positioning structure synchronously retracts or extends radially. This invention achieves synchronous linkage of the outer support through a single-point screw drive, and, combined with the independent adjustment of the inner clamping centering structure, can quickly achieve coaxial positioning of the guide tube inside the casing. It is weld-free to install, reusable, and suitable for center positioning of the guide tube inside the casing in trenchless directional drilling construction.

Description

Technical Field

[0001] This invention relates to the technical field of directional drilling equipment, and more particularly to a center positioning device for the guide tube inside a directional drilling casing. Background Technology

[0002] In trenchless directional drilling, complex geological formations are prone to collapse, typically requiring the installation of a large-diameter outer casing. Within the limited space of the outer casing, a small-diameter inner guide tube is inserted to guide the subsequent drill rods for high-precision directional drilling. In actual construction, the inner guide tube must always remain on the geometric center line of the outer casing. If the guide tube becomes eccentric, tilted, or wobbles, it will cause the subsequent drill rod trajectory to deviate, severely affecting the directional drilling's correction capability and the final accuracy of the excavation point.

[0003] Currently, the existing methods for positioning pipelines within casings mostly involve manually welding fixed-length support steel bars onto the outer wall of the guide pipe on-site. This method has the following drawbacks: First, it is not adjustable and has poor adaptability. Due to dimensional tolerances or extrusion deformation during the manufacturing and construction of the casing and guide pipe, the fixed-specification support is prone to phenomena such as "too tight to push in" or "too loose to cause shaking." Second, installation and disassembly are extremely cumbersome. On-site welding is time-consuming and labor-intensive, and it is impossible to make quick and dynamic fine adjustments to the internal positioning status during long-distance pipe advancement. Summary of the Invention

[0004] The purpose of this invention is to provide a center positioning device for the guide tube inside a directional drilling casing, which solves the above-mentioned technical problems.

[0005] The technical solution adopted in this invention is as follows: A center positioning device for the inner guide tube of a directional drilling casing includes a fixed ring, a moving ring, a single-point screw drive structure, an inner clamping centering structure, and an outer support positioning structure. The moving ring is rotatably disposed inside the fixed ring, the inner clamping centering structure is disposed inside the moving ring, and the outer support positioning structure is disposed on the fixed ring; The single-point lead screw drive structure is connected to the fixed ring and the moving ring respectively and drives the moving ring to rotate relative to the fixed ring. When the moving ring rotates, the outer support positioning structure synchronously retracts radially or synchronously extends radially.

[0006] Preferably, the fixing ring includes a first ring body, a second ring body, and a first connecting member, wherein the first ring body and the second ring body are arranged facing each other, and the first ring body and the second ring body are connected by the first connecting member; The moving ring includes an upper ring body, a lower ring body, and a second connecting member. The upper ring body and the lower ring body are arranged opposite each other and are connected by the second connecting member.

[0007] As a further preferred embodiment, the single-point lead screw drive structure includes a lead screw fixing seat, a lead screw drive seat, an adjusting lead screw, a connecting plate, an ear plate, a first rotating shaft, and a second rotating shaft. Two ear plates are provided on the outer side of the fixed ring, and the lead screw fixing seat is rotatably provided between the two ear plates through the first rotating shaft; One end of the connecting plate is connected to the upper ring body, and the other end of the connecting plate is rotatably provided with the lead screw drive seat via the second rotating shaft; The adjusting lead screw is disposed within the lead screw fixing seat and the lead screw drive seat.

[0008] As a further preferred embodiment, it also includes a limiting plate, wherein a plurality of the limiting plates are respectively provided on the upper ring body and the lower ring body, and each limiting plate is provided with a limiting hole.

[0009] As a further preferred embodiment, the device also includes a fixing block and a limiting rod. A plurality of fixing blocks are provided between the upper ring body and the lower ring body, and a limiting rod is provided at both ends of each fixing block. Each limiting rod is respectively disposed in a limiting hole.

[0010] As a further preferred embodiment, the internal clamping and centering structure includes an internal clamping block, a threaded connecting rod, and a rubber gasket; One end of the threaded connecting rod is threadedly connected to the fixed block, and the other end of the threaded connecting rod is rotatably connected to the inner clamping block. The rubber gasket is provided at the end of the inner clamping block away from the threaded connecting rod.

[0011] As a further preferred embodiment, the number of the inner clamping and centering structures is three, and the three inner clamping and centering structures are evenly distributed along the inner circumference of the moving ring at an angle of 120 degrees.

[0012] As a further preferred embodiment, the external support positioning structure includes a support rod, a limiting sleeve, and a connecting rod; One end of the support rod is sleeved around the second connector; The limiting sleeve is provided between the first ring body and the second ring body, and the two ends of the limiting sleeve are rotatably connected to the first ring body and the second ring body through the connecting rod; The other end of the support rod passes through the limiting sleeve and extends out of the fixing ring.

[0013] As a further preferred embodiment, the number of the external support positioning structures is three, and the three external support positioning structures are evenly distributed along the outer periphery of the fixing ring at an angle of 120 degrees.

[0014] The above technical solution has the following advantages or beneficial effects: (1) In this invention, by setting a single-point screw drive structure to be connected to the fixed ring and the moving ring respectively, the on-site construction personnel only need to use an ordinary socket wrench to rotate an adjusting screw to drive the moving ring to rotate relative to the fixed ring at an angle, so that the external support positioning structure can be synchronously radially retracted or synchronously radially extended, thus achieving the effect of single-point drive and synchronous linkage, avoiding the tedious process of adjusting multiple points separately, and greatly shortening the assembly time.

[0015] (2) In this invention, the fixed ring and the moving ring adopt a double-ring disc structure. The axial constraint is achieved by the limiting plate and the limiting rod, and the degree of freedom of coaxial rotation is maintained. The structure is compact and the operation is stable, so that the moving ring will not be axially offset when rotating relative to the fixed ring, thus ensuring the coaxiality of the entire positioning device.

[0016] (3) In this invention, the threaded connecting rod of the inner clamping centering structure is threadedly connected to the fixed block and rotatably connected to the inner clamping block, so that the inner clamping block can independently adjust the radial clamping distance to adapt to guide pipes of different diameters; the rubber gasket can prevent the inner clamping block from directly contacting the surface of the guide pipe and causing scratches, thus protecting the pipe wall.

[0017] (4) In this invention, three inner clamping and centering structures are evenly distributed along the inner circumference of the moving ring at a 120-degree angle, and three outer support and positioning structures are evenly distributed along the outer circumference of the fixed ring at a 120-degree angle, forming a symmetrical clamping and support structure at three points inside and outside, which ensures the coaxial positioning accuracy of the guide tube in the sleeve, has strong variable diameter adaptive capability, and can dynamically adapt to the ellipticity error of the sleeve and guide tube in the processing and manufacturing process or the slight deformation caused by the underground soil compression.

[0018] (5) In this invention, the entire device adopts a fully mechanical structure. The installation process is without welding, drilling, or damage to the pipe wall. After the construction is completed, the device can be retracted and unlocked smoothly by simply rotating the adjusting screw in the opposite direction. It can be reused repeatedly, which greatly reduces the overall construction cost. Attached Figure Description

[0019] Figure 1 This is a front structural schematic diagram of the center positioning device for the guide tube inside the directional drilling casing in this invention; Figure 2 This is a side view of the center positioning device for the guide tube inside the directional drilling casing in this invention. Figure 1 ; Figure 3This is a side view of the center positioning device for the guide tube inside the directional drilling casing in this invention. Figure 2 ; Figure 4 This is a perspective view of the center positioning device of the guide tube inside the directional drilling casing in this invention; Figure 5 This is a diagram showing the usage status of the center positioning device for the guide tube inside the directional drilling casing in this invention; Figure 6 This is a schematic diagram of the internal clamping centering structure and the limiting plate cooperating in this invention; Figure 7 This is a schematic diagram of the structure in which the external support positioning structure and the second connecting member cooperate in this invention.

[0020] In the diagram: 1. Fixed ring; 11. First ring body; 12. Second ring body; 13. First connecting piece; 2. Moving ring; 21. Upper ring body; 22. Lower ring body; 23. Fixed block; 24. Second connecting piece; 25. Limiting plate; 26. Limiting rod; 3. Single-point screw drive structure; 31. Screw fixing seat; 32. Screw drive seat; 33. Adjusting screw; 34. Connecting plate; 35. Ear plate; 36. First rotating shaft; 37. Second rotating shaft; 4. Internal clamping centering structure; 41. Internal clamping block; 42. Threaded connecting rod; 43. Rubber gasket; 44. Threaded sleeve; 5. External support positioning structure; 51. Support rod; 52. Limiting sleeve; 53. Connecting rod; 54. Rotating ring. Detailed Implementation

[0021] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be noted that terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for 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. Therefore, they should not be construed as limitations on this invention. Furthermore, terms such as "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] like Figure 1-7 As shown, a preferred embodiment is illustrated, wherein the directional drilling casing inner guide tube center positioning device includes a fixed ring 1, a moving ring 2, a single-point screw drive structure 3, an inner clamping centering structure 4, and an outer support positioning structure 5.

[0025] The fixed ring 1 is an annular disc structure, and the moving ring 2 is rotatably disposed inside the fixed ring 1, that is, the moving ring 2 is located in the inner hole of the fixed ring 1, and the outer diameter of the moving ring 2 is smaller than the inner diameter of the fixed ring 1, so that the moving ring 2 can rotate relative to the fixed ring 1. The inner clamping and centering structure 4 is disposed inside the moving ring 2 and is used to clamp the guide tube from the inside; the outer support and positioning structure 5 is disposed on the fixed ring 1 and is used to support it outward to the inner wall of the outer sleeve.

[0026] The single-point lead screw drive structure 3 is connected to both the fixed ring 1 and the moving ring 2. When the lead screw 33 is rotated, the moving ring 2 is driven to rotate relative to the fixed ring 1 at an angle. Since the outer support positioning structure 5 is connected to both the fixed ring 1 and the moving ring 2, when the moving ring 2 rotates, the outer support positioning structure 5 synchronously retracts or extends radially, thereby achieving the effect of single-point drive and synchronous linkage of the outer support.

[0027] Furthermore, as a preferred embodiment, the fixing ring 1 includes a first ring body 11, a second ring body 12, and a first connecting member 13. The first ring body 11 and the second ring body 12 are arranged opposite each other, that is, the first ring body 11 and the second ring body 12 are two parallel annular plates. The first ring body 11 and the second ring body 12 are connected by the first connecting member 13, which is a bolt, to fix the first ring body 11 and the second ring body 12 into a whole, forming a double plate structure of the fixing ring 1.

[0028] The moving ring 2 includes an upper ring body 21, a lower ring body 22, and a second connecting member 24. The upper ring body 21 and the lower ring body 22 are arranged opposite each other, that is, the upper ring body 21 and the lower ring body 22 are two parallel annular plates. The upper ring body 21 and the lower ring body 22 are connected by the second connecting member 24, which is a bolt, to fix the upper ring body 21 and the lower ring body 22 into a whole, forming a double-plate structure of the moving ring 2. Both the fixed ring 1 and the moving ring 2 adopt a double-plate structure, which reduces the overall weight while ensuring structural strength, and the space between the double plates is used to accommodate intermediate components such as the limiting plate 25 and the fixing block 23.

[0029] Furthermore, as a preferred embodiment, the single-point lead screw drive structure 3 includes a lead screw fixing seat 31, a lead screw drive seat 32, an adjusting lead screw 33, a connecting plate 34, ear plates 35, a first rotating shaft 36, and a second rotating shaft 37. Two ear plates 35 are provided on the outer side of the fixing ring 1, the two ear plates 35 being parallel and spaced apart. The lead screw fixing seat 31 is rotatably mounted between the two ear plates 35 via the first rotating shaft 36, allowing the lead screw fixing seat 31 to swing around the axis of the first rotating shaft 36. One end of the connecting plate 34 is fixedly connected to the upper ring body 21, and the other end of the connecting plate 34 is rotatably mounted with the lead screw drive seat 32 via the second rotating shaft 37, allowing the lead screw drive seat 32 to swing around the axis of the second rotating shaft 37. The adjusting lead screw 33 is disposed within the lead screw fixing seat 31 and the lead screw drive seat 32, with both ends of the adjusting lead screw 33 forming threaded pairs with the lead screw fixing seat 31 and the lead screw drive seat 32, respectively. The end of the adjusting screw 33 is equipped with a standard drive head for use with a socket wrench, which facilitates operation by on-site construction personnel.

[0030] When the lead screw 33 is rotated using a socket wrench, the screw fixing seat 31 and the screw driving seat 32 are driven to move closer or further apart via the threaded pair. Since the screw fixing seat 31 is connected to the fixed ring 1 via the ear plate 35 and the first rotating shaft 36, and the screw driving seat 32 is connected to the moving ring 2 via the connecting plate 34 and the second rotating shaft 37, the movement of the two seats relative to the fixed ring 1 causes the moving ring 2 to rotate at an angle. The arrangement of the first rotating shaft 36 and the second rotating shaft 37 allows the screw fixing seat 31 and the screw driving seat 32 to adapt to angle changes during movement, preventing jamming.

[0031] Furthermore, as a preferred embodiment, it also includes limiting plates 25. Several limiting plates 25 are respectively provided on the upper ring body 21 and the lower ring body 22, and the limiting plates 25 are connected to the upper ring body 21 or the lower ring body 22 by screws. Each limiting plate 25 has a limiting hole. The limiting plates 25 are respectively fixed to the edge portions of the upper ring body 21 and the lower ring body 22, and one edge of the limiting plate 25 extends out of the upper ring body 21 and the lower ring body 22, overlapping the first ring body 11 and the second ring body 12, thus playing an axial limiting role. This ensures that the moving ring 2 will not axially displace when rotating relative to the fixed ring 1, maintaining coaxiality and having the freedom of mutual rotation.

[0032] Furthermore, as a preferred embodiment, it also includes fixing blocks 23 and limiting rods 26. Several fixing blocks 23 are disposed between the upper ring body 21 and the lower ring body 22, serving to support and maintain the distance between them. Each fixing block 23 has limiting rods 26 at both ends, and each limiting rod 26 is disposed within a limiting hole on a limiting plate 25. The limiting rods 26 pass through the limiting holes, creating a limiting fit between the fixing blocks 23 and the limiting plate 25. When the moving ring 2 rotates relative to the fixed ring 1, the limiting plate 25 slides on the first ring body 11 and the second ring body 12, allowing the moving ring 2 to rotate relative to the fixed ring 1 while preventing radial displacement between the moving ring 2 and the fixed ring 1 through the overlapping fit between the limiting plate 25 and the fixed ring 1, thus ensuring the stability of the coaxial rotation of the two rings.

[0033] Furthermore, as a preferred embodiment, the internal clamping centering structure 4 includes an internal clamping block 41, a threaded connecting rod 42, and a rubber gasket 43. One end of the threaded connecting rod 42 is threadedly connected to the fixing block 23, i.e., the fixing block 23 has a threaded hole. The threaded connecting rod 42 can be adjusted by turning to adjust its screw depth on the fixing block 23, thereby adjusting the radial position of the internal clamping block 41. The other end of the threaded connecting rod 42 is rotatably connected to the internal clamping block 41, so that the internal clamping block 41 can rotate relative to the threaded connecting rod 42. When clamping the guide tube, the internal clamping block 41 can adapt to the curvature of the guide tube surface, ensuring surface contact rather than point contact, and improving clamping reliability. An iron plate is provided at the end of the internal clamping block 41 away from the threaded connecting rod 42, and a rubber gasket 43 is provided on the iron plate. The rubber gasket 43 directly contacts the surface of the guide tube, which can increase the friction to prevent the guide tube from sliding, and also avoid the internal clamping block 41 from making hard contact with the surface of the guide tube, causing scratches or deformation. The fixed block 23 has a threaded sleeve 44 on its side wall. The threaded connecting rod 42 passes through the threaded sleeve 44 and the fixed block 23 and is threadedly connected to the threaded sleeve 44 and the fixed block 23. The threaded sleeve 44 can support the threaded connecting rod 42, making the threaded connecting rod 42 more stable.

[0034] Furthermore, as a preferred embodiment, the number of internal clamping and centering structures 4 is three, and the three internal clamping and centering structures 4 are evenly distributed along the inner circumference of the moving ring 2 at an included angle of 120 degrees. The three internal clamping and centering structures 4 are arranged in an equilateral triangle, clamping the guide tube simultaneously from three directions, thus achieving self-centering clamping of the guide tube. Since each of the three internal clamping and centering structures 4 independently adjusts the screw depth of the threaded connecting rod 42, it can adapt to guide tubes of different diameters and compensate for the ellipticity error of the guide tube, ensuring uniform distribution of clamping force.

[0035] Furthermore, as a preferred embodiment, the external support positioning structure 5 includes a support rod 51, a limiting sleeve 52, and a connecting rod 53. One end of the support rod 51 is sleeved around the second connecting member 24, meaning one end of the support rod 51 is fitted onto the second connecting member 24 and can swing around the second connecting member 24. A limiting sleeve 52 is provided between the first ring body 11 and the second ring body 12. The limiting sleeve 52 is located between the double-plate structure of the fixed ring 1. Both ends of the limiting sleeve 52 are rotatably connected to the first ring body 11 and the second ring body 12 through the connecting rod 53, allowing the limiting sleeve 52 to rotate relative to the fixed ring 1. The other end of the support rod 51 passes through the limiting sleeve 52 and extends out of the fixed ring 1. In this embodiment, a rotating ring 54 is also included. One end of the support rod 51 is provided with a rotating ring 54, which is sleeved around the second connecting member 24. The support rod 51 is rotatably connected to the second connecting member 24 through the rotating ring 54.

[0036] When the moving ring 2 rotates relative to the fixed ring 1, since one end of the support rod 51 is sleeved on the second connecting piece 24 of the moving ring 2, the rotation of the moving ring 2 causes the support rod 51 to swing. The end of the support rod 51 passing through the limiting sleeve 52 moves radially outward or inward, realizing the synchronous radial retraction or synchronous radial extension of the outer support positioning structure 5. When the support rod 51 extends outward, the diameter of the circumscribed circle formed by the ends of the three support rods 51 increases until it is firmly pressed against the inner wall of the outer sleeve, forming a three-point symmetrical support. When the adjusting screw 33 is rotated in the opposite direction, the support rod 51 retracts inward, and the entire device is unlocked. The limiting sleeve 52 guides and limits the movement of the support rod 51, ensuring the stability of the support rod 51 during the radial retraction or extension process.

[0037] Furthermore, as a preferred embodiment, three external support positioning structures 5 are used, evenly distributed at a 120-degree angle along the outer circumference of the fixing ring 1. The three external support positioning structures 5 are arranged in an equilateral triangle, simultaneously supporting the inner wall of the outer sleeve from three directions, achieving three-point symmetrical clamping and positioning of the outer sleeve, and ensuring the coaxiality between the guide tube and the outer sleeve. The three external support positioning structures 5 synchronously retract or extend radially as the moving ring 2 rotates, eliminating the need for individual adjustment, simplifying operation, and ensuring uniform support force.

[0038] In use, first place the device in the annular space between the outer tube and the guide tube. Then, use a socket wrench to rotate the adjusting screw 33, which drives the screw fixing seat 31 and the screw driving seat 32 away from each other through the threaded pair, causing the moving ring 2 to rotate relative to the fixed ring 1 at an angle. When the moving ring 2 rotates, the support rods 51 of the three outer support positioning structures 5 extend radially synchronously until they press against the inner wall of the outer tube, achieving external three-point support positioning. At the same time, by turning the threaded connecting rods 42 of the three inner clamping centering structures 4, the inner clamping blocks 41 move radially until the rubber gaskets 43 are pressed against the surface of the guide tube, achieving internal three-point clamping centering. When disassembly is required, rotate the adjusting screw 33 in the opposite direction, and the outer support positioning structures 5 retract radially synchronously, allowing the entire device to be pulled out without destructive disassembly.

[0039] The above description is merely a preferred embodiment of the present invention and does not limit the implementation and protection scope of the present invention. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A center positioning device for the inner guide tube of a directional drilling casing, characterized in that, It includes a fixed ring (1), a moving ring (2), a single-point screw drive structure (3), an inner clamping centering structure (4), and an outer support positioning structure (5); The moving ring (2) is rotatably disposed on the inner side of the fixed ring (1), the inner clamping centering structure (4) is disposed on the inner side of the moving ring (2), and the outer support positioning structure (5) is disposed on the fixed ring (1); The single-point lead screw drive structure (3) is connected to the fixed ring (1) and the moving ring (2) respectively and drives the moving ring (2) to rotate relative to the fixed ring (1). When the moving ring (2) rotates, the external support positioning structure (5) synchronously retracts radially or synchronously extends radially.

2. The center positioning device for the inner guide tube of the directional drilling casing as described in claim 1, characterized in that, The fixing ring (1) includes a first ring body (11), a second ring body (12) and a first connector (13). The first ring body (11) and the second ring body (12) are arranged opposite each other and are connected by the first connector (13). The moving ring (2) includes an upper ring body (21), a lower ring body (22), and a second connecting member (24). The upper ring body (21) and the lower ring body (22) are arranged opposite each other and are connected by the second connecting member (24).

3. The center positioning device for the inner guide tube of the directional drilling casing as described in claim 2, characterized in that, The single-point lead screw drive structure (3) includes a lead screw fixing seat (31), a lead screw drive seat (32), an adjusting lead screw (33), a connecting plate (34), an ear plate (35), a first rotating shaft (36), and a second rotating shaft (37); Two ear plates (35) are provided on the outer side of the fixed ring (1), and the lead screw fixing seat (31) is rotatably provided between the two ear plates (35) through the first rotating shaft (36); One end of the connecting plate (34) is connected to the upper ring body (21), and the other end of the connecting plate (34) is rotatably provided with the lead screw drive seat (32) through the second rotating shaft (37); The adjusting screw (33) is disposed in the screw fixing seat (31) and the screw drive seat (32).

4. The center positioning device for the inner guide tube of the directional drilling casing as described in claim 2, characterized in that, It also includes a limiting plate (25), and a plurality of the limiting plates (25) are respectively provided on the upper ring body (21) and the lower ring body (22), and each limiting plate (25) has a limiting hole.

5. The center positioning device for the inner guide tube of the directional drilling casing as described in claim 4, characterized in that, It also includes a fixing block (23) and a limiting rod (26). A plurality of fixing blocks (23) are provided between the upper ring body (21) and the lower ring body (22). Each fixing block (23) has a limiting rod (26) at both ends. Each limiting rod (26) is respectively disposed in a limiting hole.

6. The center positioning device for the inner guide tube of the directional drilling casing as described in claim 5, characterized in that, The internal clamping and centering structure (4) includes an internal clamping block (41), a threaded connecting rod (42), and a rubber gasket (43); One end of the threaded connecting rod (42) is threadedly connected to the fixed block (23), and the other end of the threaded connecting rod (42) is rotatably connected to the inner clamping block (41). The rubber gasket (43) is provided at the end of the inner clamping block (41) away from the threaded connecting rod (42).

7. The center positioning device for the inner guide tube of the directional drilling casing as described in claim 6, characterized in that, The number of the inner clamping and centering structures (4) is three, and the three inner clamping and centering structures (4) are evenly distributed along the inner circumference of the moving ring (2) at an angle of 120 degrees.

8. The center positioning device for the inner guide tube of the directional drilling casing as described in claim 2, characterized in that, The external support positioning structure (5) includes a support rod (51), a limiting sleeve (52), and a connecting rod (53); One end of the support rod (51) is sleeved around the second connector (24); The limiting sleeve (52) is provided between the first ring body (11) and the second ring body (12), and the two ends of the limiting sleeve (52) are rotatably connected to the first ring body (11) and the second ring body (12) through the connecting rod (53); The other end of the support rod (51) passes through the limiting sleeve (52) and extends out of the fixing ring (1).

9. The center positioning device for the inner guide tube of the directional drilling casing as described in claim 8, characterized in that, The number of the external support positioning structures (5) is three, and the three external support positioning structures (5) are evenly distributed along the outer periphery of the fixed ring (1) at an angle of 120 degrees.

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