A drill pipe thread cutting apparatus

Abstract

The present application relates to the technical field of cutting equipment, and discloses a drill pipe thread cutting equipment, which comprises a fixing mechanism for fixing a drill pipe, the fixing mechanism comprises a plurality of extrusion blocks arranged in a circle, a clamping space for inserting the end of the drill pipe is enclosed between the plurality of extrusion blocks, the plurality of extrusion blocks are slidingly arranged on a support body, and a pushing piece for pushing the extrusion blocks to slide towards the middle part of the drill pipe is screwed in the support body; during the process of rotating the pushing piece to push the plurality of extrusion blocks to slide and drive the clamping space to gradually decrease so that the drill pipe is radially clamped and fixed by the plurality of extrusion blocks, the pushing piece extrudes the end face of the drill pipe to axially limit the drill pipe. According to the present application, only one action of rotating the pushing piece can simultaneously realize radial clamping of the drill pipe and axial limitation of the drill pipe, so that the drill pipe does not have the risk of axial movement when cutting threads, and the probability of defective drill pipes is reduced.

Description

A drill pipe thread cutting device Technical Field

[0001] This invention relates to the field of cutting equipment technology, and specifically to a drill pipe thread cutting device. Background Technology

[0002] Drill pipe is a steel pipe with threads at the tail, used to connect the drilling rig's surface equipment to the drilling equipment or bottom hole device located at the bottom of the well. When machining the drill pipe threads, it needs to be processed by cutting equipment. The cutting equipment makes the drill pipe rotate slowly and uniformly, while the high-speed rotating cutting tool moves continuously. As the cutting tool moves continuously, the required threads are machined on the drill pipe.

[0003] The cutting equipment is equipped with a fixing mechanism for securing the drill rod. The firmness of the drill rod fixation directly affects the quality of the threads processed by the drill rod. In the prior art, the drill rod is fixed by a three-jaw chuck. The three-jaw chuck uses the radial movement of three movable jaws evenly distributed on the chuck body to tighten and position the drill rod.

[0004] Although a three-jaw chuck uses three jaws to radially compress the drill rod, which can achieve a certain degree of fixation, its drawbacks are as follows: In actual operation, because the surface of the drill rod is very smooth before thread cutting, if the drill rod is not tightly fixed, it is easy to cause axial movement during thread cutting. Moreover, the drill rod is hollow inside, and if the compressive force on the drill rod is increased to restrict its axial movement, the risk of radial deformation of the drill rod will increase. Existing three-jaw chucks can only use three jaws to radially compress and fix the drill rod, but cannot axially limit the drill rod. In order to prevent radial deformation of the drill rod, the radial compression of the drill rod cannot be increased indiscriminately, which leads to the risk of axial movement of the drill rod when cutting threads, thus increasing the probability of defective drill rods. Summary of the Invention

[0005] The purpose of this invention is to provide a drill pipe thread cutting device to overcome the above-mentioned shortcomings in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a drill pipe thread cutting device, comprising a fixing mechanism for fixing the drill pipe, the fixing mechanism comprising a plurality of circumferentially arranged extrusion blocks, the plurality of extrusion blocks forming a clamping space for inserting the end of the drill pipe, the plurality of extrusion blocks being slidably disposed on a support body, and a pusher for pushing the extrusion blocks toward the middle of the drill pipe being screwed into the support body;

[0007] During the process of rotating the pusher to push multiple extrusion blocks to slide and gradually reduce the clamping space so that the drill rod is radially clamped and fixed by the multiple extrusion blocks, the pusher extrudes the end face of the drill rod to axially limit the drill rod.

[0008] The aforementioned drill pipe thread cutting device includes a rotating ring, in which guide blocks corresponding to multiple extrusion blocks are detachably installed. Guide grooves are provided on the side of the multiple guide blocks near the center, and a guide plate is integrally provided on the side of the extrusion block away from the center, which is slidably engaged with the guide groove.

[0009] In the aforementioned drill pipe thread cutting device, the guide groove slopes downward from the end of the drill pipe toward the middle, so that the clamping space gradually decreases as each of the extrusion blocks slides toward the middle of the drill pipe.

[0010] In the aforementioned drill pipe thread cutting device, the sides of the plurality of extrusion blocks near the center of the clamping space are concave to increase the contact area with the drill pipe.

[0011] In the aforementioned drill pipe thread cutting device, the bottom of the side of each extrusion block near the middle of the drill pipe is an inclined surface, so that when the end of the drill pipe is inserted into the clamping space, each extrusion block can be pushed to slide away from the drill pipe, thereby gradually increasing the clamping space.

[0012] The aforementioned drill pipe thread cutting device further includes an internal threaded ring detachably installed within a rotating ring. The internal threaded ring is located on the side of the plurality of extrusion blocks away from the middle of the drill pipe, and the pusher is screwed into the threaded ring.

[0013] In the aforementioned drill pipe thread cutting device, the outer surface of the rotating ring is uniformly fixed with multiple protruding teeth, and the rotating ring is rotatably mounted on the support.

[0014] The aforementioned drill pipe thread cutting device includes a pusher component comprising a stud screwed to an internal threaded ring. The stud has multiple first sliding holes and a second sliding hole. The second sliding hole is located at the center of the stud. The multiple first sliding holes communicate with the second sliding hole and are arranged circumferentially around the second sliding hole. A first pressure rod is dynamically sealed in each of the multiple first sliding holes, and a second pressure rod is dynamically sealed in the second sliding hole. The second pressure rod and the multiple first pressure rods protrude from the stud. A pressure ring corresponding to the extrusion block is fixedly installed at the end of each of the multiple first pressure rods.

[0015] In the aforementioned drill pipe thread cutting device, a first permanent magnet is fixedly embedded in each of the multiple extrusion blocks, and a second permanent magnet is fixedly embedded in the pressure ring. The first permanent magnet and the second permanent magnet correspond to each other and repel each other.

[0016] In the aforementioned drill pipe thread cutting device, the second pressure rod is made of heat-conducting metal, and a plurality of first sliding holes and a second sliding hole constitute a sealed cavity, which is filled with a thermally expanding liquid.

[0017] Beneficial Effects: In the above technical solution, the drill rod thread cutting device provided by the present invention uses multiple extrusion blocks for radially extruding and fixing the drill rod and a pusher for pushing the multiple extrusion blocks to slide on a support body. The pusher is screwed onto the support body. When the pusher is rotated, it can move towards the middle of the drill rod. The moving pusher pushes each extrusion block to move towards the middle of the drill rod. During the process of each extrusion block moving towards the middle of the drill rod, the distance between it and the drill rod gradually decreases until each extrusion block radially clamps the drill rod. At the same time, during the process of the pusher moving towards the middle of the drill rod, it gradually abuts against the end face of the drill rod and generates extrusion force, thereby axially limiting the drill rod. Based on this, compared with the prior art, the present invention can simultaneously achieve radial clamping and axial limiting of the drill rod by rotating the pusher, so that the drill rod will not have the risk of axial movement when cutting threads, reducing the probability of defective drill rods, thus effectively solving the shortcomings of the prior art. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0019] Figure 1 is a front view of the drill pipe thread cutting device after removing the cutting mechanism according to an embodiment of the present invention.

[0020] Figure 2 is a cross-sectional structural diagram of the drill rod connected to the fixing mechanism according to an embodiment of the present invention;

[0021] Figure 3 is a schematic diagram of the extrusion block provided in an embodiment of the present invention;

[0022] Figure 4 is a schematic diagram of the pusher structure provided in an embodiment of the present invention.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1. Bracket; 2. Rotating ring; 201. Protruding tooth; 202. Sliding ring; 3. Screw; 4. Stud; 401. Handle; 402. First sliding hole; 403. Second sliding hole; 5. Drill rod; 6. Gear motor; 7. Gear; 8. Guide block; 801. Guide groove; 9. Extrusion block; 901. Guide plate; 902. Concave surface; 903. First permanent magnet; 10. Internal threaded ring; 11. Second pressure rod; 12. First pressure rod; 13. Pressure ring. Detailed Implementation

[0025] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0026] As shown in Figures 1-4, an embodiment of the present invention provides a drill rod thread cutting device, including a fixing mechanism for fixing a drill rod 5. The fixing mechanism includes a plurality of extrusion blocks 9 arranged circumferentially. The plurality of extrusion blocks 9 are arranged together to form a clamping space for inserting the end of the drill rod 5. The plurality of extrusion blocks 9 are slidably disposed on a support body. A pusher is screwed into the support body for pushing the extrusion blocks 9 toward the middle of the drill rod 5.

[0027] During the process of rotating the pusher to push multiple extrusion blocks 9 to slide and gradually reduce the clamping space so that the drill rod 5 is radially clamped and fixed by the multiple extrusion blocks 9, the pusher extrudes the end face of the drill rod 5 to axially limit the drill rod 5.

[0028] The drill pipe thread cutting device provided in this embodiment is used to cut threads on the drill pipe after it has been fixed. In this embodiment, terms such as "upper" and "lower" related to position and direction are relative to the accompanying drawings. Specifically, the drill pipe thread cutting device includes a fixing mechanism for fixing the drill pipe 5, a cutting mechanism for cutting threads (not shown in the figures), and a driving mechanism for driving the drill pipe 5 to rotate. The cutting mechanism in this embodiment is the same as in the prior art and will not be described in detail. There are at least three extrusion blocks 9. The sides of the multiple extrusion blocks 9 near their centers abut against the outer surface of the drill pipe 5. The clamping space formed by the multiple extrusion blocks 9 is cylindrical. The end of the drill pipe 5 is inserted into the clamping space. The extrusion blocks 9 are slidably mounted on the support body. When the multiple extrusion blocks 9 slide back and forth, they can change the diameter of the cylindrical clamping space, thereby enabling radial clamping and fixing of drill pipes 5 of different diameters.

[0029] The pusher is screwed onto the support. When the pusher is rotated in the forward and reverse directions, it can reciprocate along the axial direction of the drill rod 5. When the pusher is rotated in the forward direction, it moves toward the extrusion blocks 9 and pushes each extrusion block 9 toward the middle of the drill rod 5. As each extrusion block 9 moves toward the middle of the drill rod 5, the clamping space gradually decreases until the drill rod 5 is radially pressed by multiple extrusion blocks 9. At the same time, as the pusher moves continuously, it can be driven to abut against the end face of the drill rod 5 and generate extrusion force on the end face of the drill rod 5 so that the drill rod 5 will not move axially.

[0030] In this embodiment, there are two fixing mechanisms, which are used to fix both ends of the drill rod 5 (as shown in Figure 1). The pushing components in the two fixing mechanisms can axially limit the two end faces of the drill rod 5, ensuring that the drill rod 5 will not move axially regardless of the direction the cutting mechanism travels. In the prior art, a three-jaw chuck is used to fix the drill rod. However, the three-jaw chuck can only use three jaws to radially compress and fix the drill rod, and cannot axially limit its movement. Furthermore, to prevent radial deformation of the drill rod, the radial compression cannot be increased excessively, which can lead to a risk of axial movement during thread cutting, thus increasing the probability of defective drill rods.

[0031] In this embodiment, multiple extrusion blocks 9 for radially pressing and fixing the drill rod 5 and a pusher for pushing the multiple extrusion blocks 9 to slide are slidably arranged on the support body, and the pusher is screwed onto the support body. When the pusher is rotated, it can move towards the middle of the drill rod 5. The moving pusher pushes each extrusion block 9 to move towards the middle of the drill rod 5. During the process of each extrusion block 9 moving towards the middle of the drill rod 5, the distance between it and the drill rod 5 gradually decreases until each extrusion block 9 radially clamps the drill rod 5. At the same time, during the process of the pusher moving towards the middle of the drill rod 5, it will gradually abut against the end face of the drill rod 5 and generate extrusion force, thereby axially limiting the drill rod 5. Based on this, compared with the prior art, the present invention can simultaneously achieve radial clamping and axial limiting of the drill rod 5 by rotating the pusher, so that the drill rod 5 will not have the risk of axial movement when cutting threads, reducing the probability of the drill rod 5 being defective, thereby effectively solving the shortcomings of the prior art.

[0032] In this embodiment, the support includes a rotating ring 2. A guide block 8 corresponding to a plurality of extrusion blocks 9 is detachably installed inside the rotating ring 2. A guide groove 801 is provided on the side of the plurality of guide blocks 8 near the center. A guide plate 901 is integrally provided on the side of the extrusion block 9 away from the center, which is slidably engaged with the guide groove 801. The front and rear sides of the guide plate 901 extend to the outside of the extrusion block 9 and slide inside the guide groove 801, so that the guide plate 901 does not detach from the guide groove 801 while sliding with the guide groove 801. At the same time, the guide groove 801 penetrates the side of the guide block 8 away from the middle of the drill rod 5, which is the side with the largest vertical distance from the drill rod 5, so as to facilitate the installation of the extrusion block 9 onto the guide block 8. The guide groove 801 does not penetrate the side of the guide block 8 near the middle of the drill rod 5, so as to limit the extrusion block 9.

[0033] The guide groove 801 slopes downwards from the end of the drill rod 5 toward the center, so that the clamping space gradually decreases as each extrusion block 9 slides toward the center of the drill rod 5, thereby enabling radial clamping of the drill rod 5. The bottom of the side of each extrusion block 9 near the center of the drill rod 5 is an inclined surface (as shown in Figure 2), so that when the end of the drill rod 5 is inserted into the clamping space, it can push each extrusion block 9 to slide away from the drill rod 5, thereby gradually increasing the clamping space, so that the drill rod 5 can be smoothly inserted into the clamping space.

[0034] Furthermore, the sides of the multiple extrusion blocks 9 near the center of the clamping space are concave surfaces 902 to increase the contact area with the drill rod 5 and improve the firmness of fixing the drill rod 5.

[0035] In this embodiment, the support body also includes an internally threaded ring 10 detachably installed within the rotating ring 2. The internally threaded ring 10 is located on the side of the plurality of pressing blocks 9 away from the middle of the drill rod 5, and the pressing element is screwed into the threaded ring 10. The plurality of guide blocks 8 and the threaded ring 10 are all detachably connected to the rotating ring 2 by a plurality of screws 3 or bolts.

[0036] In this embodiment, a plurality of protruding teeth 201 are uniformly fixed on the outer surface of the rotating ring 2. The plurality of protruding teeth 201 are arranged circumferentially with the axis of the rotating ring 2 as the center. The rotating ring 2 is rotatably mounted on the bracket 1. The driving mechanism includes a reduction motor 6. The output end of the reduction motor 6 is keyed to a gear 7 that meshes with the protruding teeth 201. When the reduction motor 6 is started, the gear 7 is driven to rotate. The gear 7 drives the rotating ring 2 to rotate. The rotation of the rotating ring 2 drives the drill rod 5, which is fixed by the fixing mechanism, to rotate.

[0037] Each fixing mechanism is equipped with two brackets 1. Each bracket 1 has an insertion port for inserting a rotating ring 2. The outer surface of the rotating ring 2 slides against the inner wall of the insertion port. At least two sliding rings 202 are fixedly installed on the outer surface of the rotating ring 2. A protruding tooth 201 is located between the two sliding rings 202. Each bracket 1 has a sliding ring groove, which corresponds one-to-one with the two sliding rings 202. The sliding rings 202 are slidably disposed within the sliding ring grooves, thus preventing axial movement of the rotating ring 2 and ensuring stable rotation. The brackets 1 are detachable, allowing the sliding ring grooves to be opened for mounting the rotating ring 2 onto the bracket 1. This detachable design of the brackets 1 is existing technology and will not be described in detail.

[0038] In this embodiment, the pressing component includes a stud 4 screwed to the internal threaded ring 10. A handle 401 is fixedly installed on the side of the stud 4 away from the drill rod 5. The stud 4 can be rotated by rotating the handle 401. The stud 4 has multiple first sliding holes 402 and a second sliding hole 403. The multiple first sliding holes 402 and the second sliding hole 403 all penetrate the side of the stud 4 near the drill rod 5. There are at least two first sliding holes 402. The second sliding hole 403 is located at the center of the stud 4 and is coaxially arranged with the clamping space. The multiple first sliding holes 402 are all connected to the second sliding hole 403 and are arranged circumferentially around the second sliding hole 403. A first pressure rod 12 is provided in each of the multiple first sliding holes 402 for dynamic sealing (referring to sliding seal). A second pressure rod 11 is provided in each of the second sliding holes 403 for dynamic sealing. The second pressure rod 11 and the multiple first pressure rods 12 all protrude from the stud 4. A pressure ring 13 corresponding to the extrusion block 9 is fixedly installed at the end of the multiple first pressure rods 12.

[0039] Specifically, when it is necessary to fix the drill rod 5, the stud 4 is rotated to move towards the drill rod 5. At this time, the stud 4 drives the second pressure rod 11 and multiple first pressure rods 12 to move towards the drill rod 5. The movement of the multiple first pressure rods 12 drives the pressure ring 13 to move synchronously. During this process, the pressure ring 13 gradually approaches each extrusion block 9, and the second pressure rod 11 gradually approaches the end face of the drill rod 5. When the second pressure rod 11 abuts against the end face of the drill rod 5, the continued rotation of the stud 4 will drive the second pressure rod 11 to generate extrusion force on the end face of the drill rod 5. Under the action of the extrusion force, the internal pressure of the first sliding hole 402 and the second sliding hole 403 increases, thereby driving the multiple first pressure rods 12 and the pressure ring 13 to move towards the extrusion block 9, so that the pressure ring 13 pushes each extrusion block 9 to slide towards the middle of the drill rod 5 until... Each extrusion block 9 abuts against the outer surface of the drill rod 5 and generates radial extrusion force. At this time, the pressure ring 13 also generates extrusion force on each extrusion block 9 to prevent each extrusion block 9 from sliding in the opposite direction, ensuring that the radial extrusion force of each extrusion block 9 on the drill rod 5 does not decrease. As the stud 4 continues to extrude, the extrusion force of the second pressure rod 11 on the end face of the drill rod 5 will continuously increase, so that the second pressure rod 11 has a strong axial limit on the drill rod 5, and the extrusion force of the pressure ring 13 on each extrusion block 9 and the extrusion force of each extrusion block 9 on the drill rod 5 will continuously increase, so that each extrusion block 9 has a strong radial fixation on the drill rod 5. Thus, it can be seen that the radial fixation of the drill rod 5 is achieved under the extrusion action of each extrusion block 9, and the axial limit of the drill rod 5 is achieved under the extrusion action of the second pressure rod 11. The radial fixation and axial limit are achieved simultaneously through the rotation of the stud 4.

[0040] Of course, during the process of rotating the stud 4 to move the stud 4 toward the drill rod 5, it is also possible that the pressure ring 13 abuts against each extrusion block 9 first, and the second pressure rod 11 abuts against the end face of the drill rod 5 later. This is the same working principle as the above-mentioned second pressure rod 11 abutting against the end face of the drill rod 5 first, and the pressure ring 13 abutting against each extrusion block 9 later. It will not be elaborated further, and they can ultimately achieve the same technical effect.

[0041] When rotating the stud 4, the studs 4 in the two fixing mechanisms can be rotated simultaneously, so that the two studs 4 move toward the drill rod 5 at the same time, thereby reducing the operation time when fixing the drill rod 5 and improving work efficiency.

[0042] In this embodiment, after the pressure ring 13 abuts against each extrusion block 9, the continued rotation of the stud 4 will cause sliding friction between the pressure ring 13 and each extrusion block 9, thereby increasing the wear of the pressure ring 13 and each extrusion block 9 (since the second sliding hole 403 is located at the center of the stud 4, the second pressure rod 11 is coaxial with the stud 4. When the second pressure rod 11 abuts against the end face of the drill rod 5, the second pressure rod 11 will rotate on its own as the stud 4 continues to rotate, and there will be no relative sliding between it and the end face of the drill rod 5, thus there is no sliding wear).

[0043] To address the wear problem between the pressure ring 13 and the extrusion blocks 9, a first permanent magnet 903 is fixedly embedded in each of the extrusion blocks 9, and a second permanent magnet (not shown in the figure) is fixedly embedded in the pressure ring 13. The first permanent magnet 903 and the second permanent magnet correspond to each other and repel each other. The second permanent magnet is annular, so that no matter what angle the pressure ring 13 rotates to, the second permanent magnet will always correspond to each of the first permanent magnets 903. By utilizing the mutual repulsion between the first permanent magnet 903 and the second permanent magnet, even if each extrusion block 9 is subjected to a large extrusion force from the pressure ring 13, the pressure ring 13 will not come into contact with each extrusion block 9. This prevents sliding friction between the pressure ring 13 and each extrusion block 9, thus preventing wear between them and effectively solving the aforementioned technical problem.

[0044] Furthermore, the second pressure rod 11 is made of thermally conductive metal, and a plurality of first sliding holes 402 and a second sliding hole 403 constitute a sealed cavity, which is filled with a thermally expanding liquid.

[0045] Specifically, when the drill rod 5 is threaded, a large amount of heat is generated on the drill rod 5, causing the temperature of the drill rod 5 to rise sharply. The heat-conducting metal material of the second pressure rod 11 allows the heat on the drill rod 5 to be transferred to the second pressure rod 11, which then transfers the heat to the thermally expanding liquid, thereby achieving the purpose of cooling the drill rod 5.

[0046] At the same time, due to the expansion of the thermally expanding liquid after absorbing heat, the internal pressure of the sealed cavity increases. The increased internal pressure of the sealed cavity drives the second pressure rod 11 to increase the extrusion force on the drill rod 5, the pressure ring 13 to each extrusion block 9, and the extrusion force of each extrusion block 9 to the drill rod 5 to increase, so that the radial fixation and axial limitation of the drill rod 5 are more secure, and the more the drill rod 5 is threaded, the better its fixation effect becomes.

[0047] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A drill pipe thread cutting device, comprising a fixing mechanism for fixing the drill pipe (5), characterized in that: The fixing mechanism includes a plurality of circumferentially arranged extrusion blocks (9), which together form a clamping space for inserting the end of the drill rod (5). The plurality of extrusion blocks (9) are slidably disposed on a support body, and a pusher is screwed into the support body for pushing the extrusion blocks (9) toward the middle of the drill rod (5). During the process of rotating the pusher to push the plurality of extrusion blocks (9) to slide and gradually reduce the clamping space so that the drill rod (5) is radially clamped and fixed by the plurality of extrusion blocks (9), the pusher extrudes the drill rod (5). The end face is used to axially limit the drill rod (5); the support body includes a rotating ring (2), and a guide block (8) corresponding to a plurality of extrusion blocks (9) is detachably installed in the rotating ring (2). The plurality of guide blocks (8) have guide grooves (801) on their sides near the center. The side of the extrusion block (9) away from the center is integrally provided with a guide plate (901) that slides and engages with the guide groove (801); the support body also includes an internally threaded ring (10) detachably installed in the rotating ring (2). Located on one side away from the middle of the drill rod (5) of multiple extrusion blocks (9), the pusher is screwed into the internal threaded ring (10); the pusher includes a stud (4) screwed to the internal threaded ring (10), the stud (4) having multiple first sliding holes (402) and a second sliding hole (403), the second sliding hole (403) being located at the center of the stud (4), the multiple first sliding holes (402) communicating with the second sliding hole (403) and circumferentially arranged around the second sliding hole (403), and the multiple first sliding holes (402) having dynamic seals. A first pressure rod (12) is provided, and a second pressure rod (11) is provided in the dynamic seal of the second sliding hole (403). The second pressure rod (11) and multiple first pressure rods (12) protrude from the stud (4). The ends of multiple first pressure rods (12) are fixedly installed with pressure rings (13) corresponding to the extrusion blocks (9). A first permanent magnet (903) is fixedly embedded on each of the multiple extrusion blocks (9), and a second permanent magnet is fixedly embedded on the pressure ring (13). The first permanent magnet (903) and the second permanent magnet correspond to each other and repel each other.

2. The drill pipe thread cutting device according to claim 1, characterized in that: The guide groove (801) slopes downward from the end of the drill rod (5) toward the middle so that the clamping space gradually decreases as each of the extrusion blocks (9) slides toward the middle of the drill rod (5).

3. The drill pipe thread cutting device according to claim 1, characterized in that: The sides of the multiple extrusion blocks (9) near the center of the clamping space are concave (902) to increase the contact area with the drill rod (5).

4. The drill pipe thread cutting device according to claim 1, characterized in that: The bottom of the side of each of the extrusion blocks (9) near the middle of the drill rod (5) is inclined so that when the end of the drill rod (5) is inserted into the clamping space, each of the extrusion blocks (9) can be pushed to slide away from the drill rod (5), thereby gradually increasing the clamping space.

5. The drill pipe thread cutting device according to claim 1, characterized in that: The outer surface of the rotating ring (2) is uniformly fixed with multiple protruding teeth (201), and the rotating ring (2) is rotatably mounted on the bracket (1).

6. The drill pipe thread cutting device according to claim 1, characterized in that: The second pressure rod (11) is made of thermally conductive metal, and a plurality of first sliding holes (402) and a second sliding hole (403) constitute a sealed cavity, which is filled with a thermally expanding liquid.

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