Flexible drill pipe with impact inertia back-off

Abstract

This invention discloses a flexible drill rod with impact inertia uncoupling, comprising a lower connector and an outer tube. One end of the lower connector extends into the outer tube; the other end of the outer tube is fitted with an active drill rod, one end of which extends into the outer tube; a spring is installed between the lower connector and the active drill rod; a first annular groove is arranged on the end face of the lower connector extending into the outer tube; a second annular groove is arranged on the end face of the active drill rod extending into the outer tube; a third annular groove is arranged on the outer surface of the end of the active drill rod extending into the outer tube; and a fourth annular groove is arranged on the inner wall of the outer tube facing the lower connector. The flexible drill rod with impact inertia uncoupling of this invention achieves three states between the active drill rod and the annular keyway of the lower connector: upper engagement, non-engagement, and lower engagement. Through state changes, normal rotary drilling and normal rotary retraction can be achieved, as well as impact inertia uncoupling, improving the success rate of drill rod uncoupling.

Description

Technical Field

[0001] This invention belongs to the field of underground coal mining technology, and relates to flexible drill pipes, specifically a flexible drill pipe with impact inertia uncoupling. Background Technology

[0002] Drilling is a crucial method for solving problems such as gas extraction, water control, and stress reduction in coal mines. Drill rods are essential tools in drilling operations, transmitting power from the drilling rig to the drill bit to break rocks. During drilling, the drill rods are subjected to various complex alternating loads, including feed force, pull-out force, torque, bending, vibration, and friction. The drill rods are connected by threads, and these complex alternating loads result in tight threaded connections, making it difficult to unscrew the drill rods during retraction. Furthermore, the tight threaded connections can lead to sliding friction between the drill rod and the chuck, or between the drill rod and the power head chuck, causing severe wear on the active drill rod and significantly impacting its service life.

[0003] Currently, in coal mines, drill pipe uncoupling is achieved by clamping the passive drill pipe inside the hole with a drill rig chuck, and then forcefully reversing the power head to uncouple the active drill pipe. The tight threaded connection of the drill pipe easily leads to sliding friction between the drill pipe and the chuck, and between the drill pipe and the power head chuck, causing severe wear on the active drill pipe and significantly impacting its service life.

[0004] In order to improve the success rate of unhooking in the power head, existing technologies have designed a vise to assist unhooking at the power head connection end, eliminating the rotational unhooking resistance of the power head, and designing a pressure sensor to limit system pressure and reduce wear on the drill rod body; however, the hydraulic control system disclosed in this patent is cumbersome and fails to fundamentally increase the unhooking force of the drilling rig. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a flexible drill rod with impact inertia uncoupling, thereby solving the problem that in existing technologies, sliding friction between the drill rod and the clamp, and between the drill rod and the power head chuck, easily occurs during drill rod uncoupling, resulting in severe wear of the active drill rod body and seriously affecting the service life of the drill rod.

[0006] To solve the above technical problems, the present invention adopts the following technical solution: a flexible drill rod with impact inertia uncoupling, comprising a lower connector and an outer tube sleeved on the outside of one end of the lower connector, with one end of the lower connector extending into the outer tube;

[0007] The other end of the outer tube is also fitted with an active drill rod, one end of which extends into the outer tube;

[0008] A spring is also installed between the lower connector and the active drill pipe. One end of the spring contacts the first thrust bearing that is snapped into the lower connector, and the other end of the spring contacts the second thrust bearing that is snapped into the active drill pipe.

[0009] The end face of the lower connector that extends into the outer tube is also provided with a first annular groove.

[0010] A second annular groove is arranged on the end face of the end of the active drill rod that extends into the outer tube, and a third annular groove is arranged on the outer surface of the end of the active drill rod that extends into the outer tube, on the side opposite to the second annular groove.

[0011] A fourth annular groove is arranged on the inner wall of the lower end of the outer tube connector.

[0012] The first annular slot mates with the second annular slot, and the third annular slot mates with the fourth annular slot.

[0013] The present invention also has the following technical features:

[0014] The lower connector includes a hollow cylindrical lower connector body and a drill rod connecting cavity, a first through cavity, and a first spring receiving cavity that are sequentially opened through the lower connector body;

[0015] The inner wall of the drill rod connecting cavity is provided with fine threads, and the outer side of the corresponding lower connector body is provided with large threads.

[0016] The lower connector body has a drill rod connecting cavity at one end, and multiple slots are provided therein. The slots are provided along the axial direction of the lower connector body and penetrate the drill rod connecting cavity.

[0017] The lower connector body is also provided with a first connecting thread in the middle of its outer wall;

[0018] The inner wall of the first spring receiving cavity near the first through cavity is also provided with a first retaining spring groove along the circumferential direction, and a first retaining spring is installed in the first retaining spring groove.

[0019] The first bearing mounting cavity is formed between the first snap ring groove and the end of the first spring receiving cavity facing the first through cavity, and the first thrust bearing is installed in the first bearing mounting cavity.

[0020] The lower connector body has a large thread at one end, and a control ring is also sleeved thereon. The control ring includes a hollow cylindrical ring body and a control ring thread formed on the inner wall of the ring body. The control ring thread mates with the large thread.

[0021] The outer tube includes a hollow cylindrical outer tube body and a second connecting thread formed on the inner wall of one end of the outer tube body, wherein the second connecting thread mates with the connecting thread.

[0022] The fourth annular groove is formed on the inner wall of the outer tube body at the end away from the second connecting thread.

[0023] The active drill pipe includes a cylindrical drill pipe body and a second spring receiving cavity and a second through cavity that are sequentially opened through the drill pipe body;

[0024] The active drill pipe also includes a connecting flange installed at one end of the drill pipe body. The connecting flange has a flange cavity along its own axis and the flange cavity communicates with the second through cavity.

[0025] The other end of the drill pipe body connected to the connecting flange is located inside the outer tube body;

[0026] The second annular groove is installed on the outer surface of the drill pipe body at one end inside the outer tube body, and the third annular groove is installed on the outer surface of the drill pipe body at one end inside the outer tube body, located between the second annular groove and the connecting flange.

[0027] The active drill rod also includes a second snap ring groove formed circumferentially on the inner wall of the second spring receiving cavity, and a second snap ring is installed in the second snap ring groove;

[0028] The second snap ring groove and the end of the second spring receiving cavity facing the second through cavity form a second bearing mounting cavity, and the second thrust bearing is installed in the second bearing mounting cavity;

[0029] One end of the spring is installed in the first spring receiving cavity, and the other end is installed in the second spring receiving cavity;

[0030] Compared with the prior art, the present invention has the following technical effects:

[0031] (I) The flexible drill pipe with impact inertia uncoupling of the present invention realizes three states between the active drill pipe and the annular keyway of the lower connector: upper engagement, non-engagement, and lower engagement. Through state changes, normal rotary drilling and normal rotary retraction can be realized, as well as impact inertia uncoupling, thereby improving the success rate of drill pipe uncoupling.

[0032] (II) The overall structure of the present invention has the characteristics of simple structure, low cost, high load-bearing capacity, high reliability and easy maintenance. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0034] Figure 2 This is a schematic diagram of the lower connector structure of the present invention;

[0035] Figure 3 This is a schematic diagram of the control ring structure of the present invention;

[0036] Figure 4 This is a schematic diagram of the outer tube structure of the present invention;

[0037] Figure 5This is a schematic diagram of the active drill pipe structure of the present invention;

[0038] The meanings of the labels in the attached diagram are as follows:

[0039] 1-Lower connector, 2-Outer tube, 3-Active drill rod, 4-Spring, 5-First thrust bearing, 6-Second thrust bearing, 7-First annular groove, 8-Second annular groove, 9-Third annular groove, 10-Fourth annular groove;

[0040] 1-1 Lower connector body, 1-2 Drill rod connecting cavity, 1-3 First through cavity, 1-4 First spring receiving cavity, 1-5 Fine thread, 1-6 Large thread, 1-7 Groove, 1-8 First connecting thread, 1-9 First snap ring groove, 1-10 First snap ring, 1-11 First bearing mounting cavity, 1-12 Control ring;

[0041] 1-12-1 Ring body, 1-12-2 Control ring thread;

[0042] 2-1 Outer tube body, 2-2 Second connecting thread;

[0043] 3-1 Drill pipe body, 3-2 Second spring receiving cavity, 3-3 Second through cavity, 3-4 Connecting flange, 3-5 Flange cavity, 3-6 Second snap ring groove, 3-7 Second snap ring, 3-8 Second bearing mounting cavity;

[0044] The specific content of the present invention will be further explained in detail below with reference to the embodiments. Detailed Implementation

[0045] Unless otherwise specified, all components in this invention are components known in the prior art.

[0046] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0047] Example 1:

[0048] Following the above technical solutions, such as Figures 1-5 As shown, a flexible drill rod with impact inertia detachment includes a lower connector 1 and an outer tube 2 sleeved on the outside of one end of the lower connector 1, with one end of the lower connector 1 extending into the outer tube 2.

[0049] The other end of the outer tube 2 is also fitted with an active drill rod 3, one end of which extends into the outer tube 2;

[0050] A spring 4 is also installed between the lower connector 1 and the active drill rod 3. One end of the spring 4 contacts the first thrust bearing 5 that is snapped into the lower connector 1, and the other end of the spring 4 contacts the second thrust bearing 6 that is snapped into the active drill rod 3.

[0051] The end face of the lower connector 1 that extends into the outer tube 2 is also provided with a first annular groove 7.

[0052] The end face of the active drill rod 3 that extends into the outer tube 2 is also provided with a second annular groove 8, and the outer surface of the active drill rod 3 that extends into the outer tube 2 is provided with a third annular groove 9 on the side opposite to the second annular groove 8.

[0053] A fourth annular groove 10 is arranged on the inner wall of one end of the outer tube 2 facing downward to the connector 1.

[0054] The first annular slot 7 cooperates with the second annular slot 8, and the third annular slot 9 cooperates with the fourth annular slot 10.

[0055] The active drill rod 3 is connected to the drill rig power head via a flange to provide rotational torque and feed and pull-out force. The other end of the active drill rod 3 is connected to the lower connector 1 via the second thrust bearing 6, spring 4, and first thrust bearing 5. The lower connector 1 and the active drill rod 3 are equipped with snap rings to limit the thrust bearings. The outer tube 2 is connected to the lower connector 1 via a thread, and the lower connector 1 is connected to the passive drill rod via a thread.

[0056] ① When the active drill rod 3 has no axial feed force and no pulling force, the spring 4 is in a free state. The active drill rod 3 and the lower connector 1 are connected by the first thrust bearing 5 and the second thrust bearing 6, and there is no torque transmission.

[0057] ② When the active drill rod 3 is fed in or pulled out, the second annular groove 8 on the active drill rod 3 engages with the first annular groove 7 on the lower connector 1, or the third annular groove 9 on the active drill rod 3 engages with the fourth annular groove 10 on the outer tube 2, so as to transmit the torque of the active drill rod 3 to the lower connector 1, thereby enabling the active drill rod 3 to drive the lower connector 1 to rotate in the forward or reverse direction.

[0058] This invention enables the rotational torque of the active drill rod 3 to be instantaneously transmitted to the lower connector 1 by changing the position between the active drill rod 3, the lower connector 1, and the outer pipe 2, thereby generating a large inertial torque uncoupling and improving the success rate of inertial uncoupling between the lower connector 1 and the passive drill rod.

[0059] As a preferred embodiment:

[0060] The lower connector 1 includes a hollow cylindrical lower connector body 1-1 and a drill rod connecting cavity 1-2, a first through cavity 1-3 and a first spring receiving cavity 1-4 that are sequentially opened through the lower connector body 1-1;

[0061] The inner wall of the drill rod connecting cavity 1-2 is provided with fine threads 1-5, and the outer side of the lower connector body 1-1 corresponding to the drill rod connecting cavity 1-2 is provided with large threads 1-6.

[0062] The lower connector body 1-1 has a drill rod connecting cavity 1-2 at one end and a plurality of slots 1-7 are also provided. The slots 1-7 are provided along the axial direction of the lower connector body 1-1 and penetrate the drill rod connecting cavity 1-2.

[0063] The lower connector body 1-1 is provided with a first connecting thread 1-8 in the middle of its outer wall.

[0064] The large thread 1-6 is used to connect the control ring 1-12, the first connecting thread 1-8 is used to connect the outer tube 2, and the fine thread 1-5 is connected to the drill rod inside the hole.

[0065] The notch 1-7 is longer than the fine thread 1-5. The inner diameter of the fine thread 1-5 is slightly smaller than the diameter of the drill rod inside the hole. The notch 1-7 is designed to allow the drill rod inside the hole to smoothly enter the fine thread 1-5.

[0066] As a preferred embodiment:

[0067] The inner wall of the first spring receiving cavity 1-4 near the first through cavity 1-3 is also provided with a first snap ring groove 1-9 along the circumferential direction, and a first snap ring 1-10 is installed in the first snap ring groove 1-9; for limiting the first thrust bearing 5.

[0068] The first snap ring groove 1-9 and the first spring receiving cavity 1-4 at one end facing the first through cavity 1-3 form a first bearing mounting cavity 1-11, and the first thrust bearing 5 is installed in the first bearing mounting cavity 1-11.

[0069] As a preferred embodiment:

[0070] The lower connector body 1-1 has a large thread 1-6 on one end, and a control ring 1-12 is also sleeved on it. The control ring 1-12 includes a hollow cylindrical ring body 1-12-1 and a control ring thread 1-12-2 opened on the inner wall of the ring body 1-12-1. The control ring thread 1-12-2 is engaged with the large thread 1-6.

[0071] The control ring 1-12 has a control ring thread 1-12-2 inside, which connects to the large thread 1-6 on the lower connector 1; the lower connector 1 uses the control ring 1-12 to tighten or loosen the drill rod inside the hole.

[0072] The lower connector 1 has a diameter of φ98mm and is divided into two sets of threads, inner and outer. The outer thread is a large thread 1-6 with a pitch of 14mm, and the inner thread is a fine thread 1-5 with a pitch of 4mm. The lower connector 1 has 4 slots 1-7. The length of slots 1-7 is greater than the length of fine thread 1-5. The design of slots 1-7 makes the radial diameter of the lower connector 1 variable.

[0073] The control ring 1-12 is equipped with a control ring thread 1-12-2 with a large pitch of 14mm, which meshes with the lower connector 1. After the drill rod in the hole enters the lower connector 1, the control ring 1-12 is turned to lock the drill rod in the hole.

[0074] As a preferred embodiment:

[0075] The outer tube 2 includes a hollow cylindrical outer tube body 2-1 and a second connecting thread 2-2 formed on the inner wall of one end of the outer tube body 2-1. The second connecting thread 2-2 is engaged with the first connecting thread 1-8.

[0076] The fourth annular groove 10 is formed on the inner wall of the outer tube body 2-1 at the end away from the second connecting thread 2-2.

[0077] The outer tube 2 has a second connecting thread 2-2 machined at one end, which connects to the first connecting thread 1-8 on the lower connector 1 to fix the position of the two. The other end is provided with a petal-shaped fourth annular groove 10, which can mesh with the third annular groove 9 of the active drill rod 3 to transmit torque.

[0078] One end of the outer tube 2 is connected to the first connecting thread (1-8) of the lower connector 1, and the other end is designed with a fourth annular groove 10. When the drill is lifted, the spring 4 is stretched, and the third annular groove (9) on one side of the active drill rod 3 engages with the fourth annular groove 10 of the outer tube 2, providing the retraction torque. When the spring 4 is in a free or compressed state, there is no torque transmission between the active drill rod 3 and the outer tube 2. The diameter of the outer tube 2 is the same as the diameter of the control rings 1-12, both being φ114mm.

[0079] As a preferred embodiment:

[0080] The active drill rod 3 includes a cylindrical drill rod body 3-1 and a second spring receiving cavity 3-2 and a second through cavity 3-3 sequentially opened within the drill rod body 3-1;

[0081] The active drill pipe 3 also includes a connecting flange 3-4 installed at one end of the drill pipe body 3-1. A flange cavity 3-5 is provided on the connecting flange 3-4 along its own axis, and the flange cavity 3-5 communicates with the second through cavity 3-3.

[0082] The drill pipe body 3-1 is connected to a connecting flange 3-4 at the other end, which is located inside the outer pipe body 2-1.

[0083] The second annular groove 8 is installed on the outer surface of the drill pipe body 3-1 at one end inside the outer tube body 2-1, and the third annular groove 9 is installed on the outer surface of the drill pipe body 3-1 at one end inside the outer tube body 2-1, located between the second annular groove 8 and the connecting flange 3-4.

[0084] As a preferred embodiment:

[0085] The active drill rod 3 also includes a second snap ring groove 3-6 formed along the circumferential direction on the inner wall of the second spring receiving cavity 3-2, and a second snap ring 3-7 is installed in the second snap ring groove 3-6;

[0086] The second snap ring groove 3-6 and the end of the second spring receiving cavity 3-2 facing the second through cavity 3-3 form a second bearing mounting cavity 3-8, and the second thrust bearing 6 is installed in the second bearing mounting cavity 3-8;

[0087] One end of the drill rod body 3-1 is connected to a connecting flange 3-4, which has 6 sets of threaded holes for fixing the active drill rod 3 and the drilling rig power head. The outer surface of the other end of the drill rod body 3-1 is provided with a second annular groove 8 and a third annular groove 9 in two directions. When the drilling rig feeds, the second annular groove 8 on the active drill rod 3 engages with the first annular groove 7 on the lower connector. When the drilling rig pulls out, the third annular groove 9 on the active drill rod 3 engages with the fourth annular groove 10 on the outer tube 2, ensuring that the drilling rig can transmit torque to the lower connector 1 whether it is feeding or pulling out.

[0088] The second spring receiving cavity 3-2, the second through cavity 3-3 and the flange cavity 3-5 constitute the flushing fluid channel;

[0089] The drill rod body 3-1 has a diameter of φ78mm and is designed with two sets of petal-shaped second annular grooves 8 and third annular grooves 9. The outer diameter of the second annular grooves 8 and third annular grooves 9 is the same as the outer diameter of the lower connector 1, φ98mm. The active drill rod 3 is connected to the power end of the drilling rig through a connecting flange 3-4. The connecting flange 3-4 is designed with eight φ16mm threaded holes. The active drill rod 3 is connected to the lower connector 1 through a second thrust bearing 6, a second retaining spring 3-7, and a spring 4. Both the active drill rod 3 and the lower connector 1 are designed with annular keyways. The keyways have a petal structure, which facilitates axial engagement. When spring 4 is in a free state, the active drill 3 is separated from the lower connector 1, and the rotational torque of the active drill rod 3 is not transmitted to the lower connector 1. The active drill rod 3 is in a "free-spinning" state. The first thrust bearing 5 and the second thrust bearing 6 are used to reduce the rotational resistance of the active drill rod 3. The two retaining rings, the first retaining ring 1-10 and the second retaining ring 3-7, are respectively placed in the first retaining ring groove 1-9 and the second retaining ring groove 3-6 of the lower connector 1 and the active drill rod 3, for limiting the spring 4. The first thrust bearing 5 and the second thrust bearing 6 are limited by the two retaining rings, which serve to connect the lower connector 1 and the active drill rod 3, but do not transmit torque.

[0090] As a preferred embodiment:

[0091] One end of the spring 4 is installed in the first spring receiving cavity 1-4, and the other end is installed in the second spring receiving cavity 3-2.

[0092] The specific working process of this invention:

[0093] Step 1: The active drill rod 3 is connected to the power head of the drilling rig via the connecting flange 3-4. The feed force, pulling force, and rotation torque of the power head are all applied to the active drill rod 3. During normal drilling, the drilling rig rotates to feed, and the active drill rod 3 compresses the spring 4, which in turn drives the first thrust bearing 5 and the second thrust bearing 6 to rotate. The petal-shaped second annular groove 8 at the front end of the active drill rod 3 engages with the petal-shaped first annular groove 7 of the lower connector 1, transmitting the torque of the power head to the lower connector 1, and the drilling rig achieves normal drilling.

[0094] Step 2: After drilling is completed, the drill is retracted. The power head pulls up and drives the active drill rod 3 to put the spring 4 in a stretched state. The petal-shaped third annular groove 9 at the rear end of the active drill rod 3 engages with the petal-shaped fourth annular groove 10 of the outer tube 2, transmitting the torque of the power head to the lower connector 1 through the outer tube 2, and the drill rig rotates and retracts.

[0095] Step 3: After the drill is withdrawn, the joint needs to be uncoupled. The drill rig does not provide feed or pull-out force. The spring 4 is in a free state. There is no torque transmission between the active drill rod 3, the lower connector 1, and the outer tube 3. It only achieves reverse rotation under the action of the first thrust bearing 5 and the second thrust bearing 6. After the active drill rod 3 reaches a certain speed, the drill rig power head is quickly fed in. The active drill rod 3 provides the lower connector 1 with rotational impulse in the high-speed rotation state, realizing inertial uncoupling.

[0096] Assuming there is no sliding friction between the drilling rig and the driven drill pipe, the drill pipe uncoupling requires the drilling rig to apply a rotational force to the drill pipe that is greater than the frictional force between the drill pipe threads. When using an impact inertia uncoupling flexible drill pipe, when the driven drill pipe is in a rotating state and then contacts the driven drill pipe, the difference in their rotational speeds increases the rotational inertia of the driven drill pipe. The inertial force provided by this rotational inertia increases the uncoupling force of the drill pipe.

[0097] The uncoupling force F in the conventional uncoupling method is the frictional force generated by the preload of the drill pipe thread, that is:

[0098]

[0099] Using an impact-inertia flexible drill pipe, after the drilling rig changes the rotational angular velocity ω0 of the active drill pipe from 0 rad / min to the normal operating rotational angular velocity ω1 = 240π rad / min, the rotational angular velocity ω0 of the driven drill pipe remains 0 rad / min. Therefore, it will be subject to an additional rotational inertial force from the active drill pipe. The unhooking force F of the impact-inertia flexible drill pipe is:

[0100]

[0101] Where F is the unlatching force between the drill pipe threads, μ is the thread friction coefficient, σ is the yield strength of the thread material, D1 is the drill pipe thread pitch diameter, D2 is the drill pipe body diameter, m is the drill pipe mass, ω0 is the initial angular velocity of the drill pipe, ω1 is the angular velocity of the drill pipe during normal operation, and t is the time for the drill pipe threads to loosen.

[0102] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions conceived by those skilled in the art within the scope of the technology disclosed in the present invention without creative effort are covered within the scope of protection of the present invention.

Claims

1. A flexible drill pipe with impact inertia detachment, comprising a lower connector (1) and an outer tube (2) sleeved on the outside of one end of the lower connector (1), wherein one end of the lower connector (1) extends into the outer tube (2); The other end of the outer tube (2) is also fitted with an active drill rod (3), one end of which extends into the outer tube (2). The characteristic feature is that... A spring (4) is also installed between the lower connector (1) and the active drill rod (3). One end of the spring (4) contacts the first thrust bearing (5) that is snapped into the lower connector (1), and the other end of the spring (4) contacts the second thrust bearing (6) that is snapped into the active drill rod (3). The end face of the lower connector (1) that extends into the outer tube (2) is also provided with a first annular groove (7). A second annular groove (8) is arranged on the end face of the active drill rod (3) that extends into the outer tube (2). A third annular groove (9) is arranged on the outer surface of the active drill rod (3) that extends into the outer tube (2) on the side opposite to the second annular groove (8). A fourth annular groove (10) is arranged on the inner wall of the outer tube (2) that faces the connector (1) downwards. The first annular slot (7) is engaged with the second annular slot (8), and the third annular slot (9) is engaged with the fourth annular slot (10); When the active drill rod (3) has no axial feed force and no pulling force, the spring (4) is in a free state, and the active drill rod (3) is connected to the lower joint (1) through the first thrust bearing (5) and the second thrust bearing (6), with no torque transmission; When the active drill rod (3) is fed in or pulled out, the second annular groove (8) on the active drill rod (3) engages with the first annular groove (7) on the lower connector (1), or the third annular groove (9) on the active drill rod (3) engages with the fourth annular groove (10) on the outer tube (2), so as to transmit the torque of the active drill rod (3) to the lower connector (1) and realize the active drill rod (3) driving the lower connector (1) to rotate in the forward or reverse direction.

2. The flexible drill pipe with impact inertia uncoupling as described in claim 1, characterized in that, The lower connector (1) includes a hollow cylindrical lower connector body (1-1) and a drill rod connecting cavity (1-2), a first through cavity (1-3) and a first spring receiving cavity (1-4) that are sequentially opened in the lower connector body (1-1). The inner wall of the drill pipe connecting cavity (1-2) is provided with fine threads (1-5), and the outer side of the lower connector body (1-1) corresponding to the drill pipe connecting cavity (1-2) is provided with large threads (1-6). The lower connector body (1-1) has a drill rod connecting cavity (1-2) at one end, and a plurality of slots (1-7) are also provided. The slots (1-7) are opened along the axial direction of the lower connector body (1-1) and pass through the drill rod connecting cavity (1-2). The lower connector body (1-1) is provided with a first connecting thread (1-8) in the middle of its outer wall.

3. The flexible drill pipe with impact inertia uncoupling as described in claim 2, characterized in that, The inner wall of the first spring receiving cavity (1-4) near the first through cavity (1-3) is also provided with a first snap ring groove (1-9) along the circumferential direction, and a first snap ring (1-10) is installed in the first snap ring groove (1-9). The first snap ring groove (1-9) and the first spring receiving cavity (1-4) facing the first through cavity (1-3) form a first bearing mounting cavity (1-11), and the first thrust bearing (5) is installed in the first bearing mounting cavity (1-11).

4. The flexible drill pipe with impact inertia uncoupling as described in claim 2, characterized in that, The lower connector body (1-1) is provided with a large thread (1-6) at one end and a control ring (1-12) is also sleeved thereon. The control ring (1-12) includes a hollow cylindrical ring body (1-12-1) and a control ring thread (1-12-2) formed on the inner wall of the ring body (1-12-1). The control ring thread (1-12-2) is engaged with the large thread (1-6).

5. The flexible drill pipe with impact inertia uncoupling as described in claim 4, characterized in that, The outer tube (2) includes a hollow cylindrical outer tube body (2-1) and a second connecting thread (2-2) opened on the inner wall of one end of the outer tube body (2-1), wherein the second connecting thread (2-2) is engaged with the first connecting thread (1-8); The fourth annular groove (10) is located on the inner wall of the outer tube body (2-1) at the end away from the second connecting thread (2-2).

6. The flexible drill pipe with impact inertia uncoupling as described in claim 5, characterized in that, The active drill pipe (3) includes a cylindrical drill pipe body (3-1) and a second spring receiving cavity (3-2) and a second through cavity (3-3) that are sequentially opened in the drill pipe body (3-1). The active drill pipe (3) also includes a connecting flange (3-4) installed at one end of the drill pipe body (3-1). A flange cavity (3-5) is provided on the connecting flange (3-4) along its own axis, and the flange cavity (3-5) communicates with the second through cavity (3-3). The other end of the drill pipe body (3-1) connected to the connecting flange (3-4) is located inside the outer tube body (2-1); The second annular groove (8) is installed on the outer surface of the drill pipe body (3-1) at one end inside the outer tube body (2-1), and the third annular groove (9) is installed on the outer surface of the drill pipe body (3-1) at one end inside the outer tube body (2-1), located between the second annular groove (8) and the connecting flange (3-4).

7. The flexible drill pipe with impact inertia uncoupling as described in claim 6, characterized in that, The active drill rod (3) further includes a second snap ring groove (3-6) opened circumferentially on the inner wall of the second spring receiving cavity (3-2), and a second snap ring (3-7) is installed in the second snap ring groove (3-6). The second snap ring groove (3-6) and the end of the second spring receiving cavity (3-2) facing the second through cavity (3-3) form a second bearing mounting cavity (3-8), and the second thrust bearing (6) is installed in the second bearing mounting cavity (3-8).

8. The flexible drill pipe with impact inertia uncoupling as described in claim 7, characterized in that, One end of the spring (4) is installed in the first spring receiving cavity (1-4), and the other end is installed in the second spring receiving cavity (3-2).

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