A connecting structure of a drill rod core pipe steel pipe and a lower connector and a drill rod core pipe assembly

Abstract

The utility model discloses a kind of connecting structure of drill pipe core pipe steel pipe and lower connector and drill pipe core pipe assembly, it is related to drill pipe field, wherein the connecting structure of drill pipe core pipe steel pipe and lower connector includes the reinforcing sleeve of the core pipe steel pipe outer periphery is sleeved, reinforcing sleeve lower end surface and lower connector form first welding joint, reinforcing sleeve inner periphery surface is equipped with guide groove group for key strip to pass through, multiple key strips are arranged along the core pipe steel pipe circumferential direction interval, key strip extension section lower end surface and lower connector form second welding joint, reinforcing sleeve and key strip form third welding joint;It further includes the drill pipe core pipe assembly using the connecting structure, spring seat is sleeved on lower connector and is coaxially arranged with core pipe steel pipe, the present application reduces the cross-section mutation near the connecting position of core pipe steel pipe and lower connector, enhances the overall strength nearby, simultaneously reduce the stress concentration formed by welding to overall structure.

Description

Technical Field

[0001] This utility model relates to the field of drill pipe technology, and more specifically, to a connection structure between a drill pipe core tube steel pipe and a lower connector, and a drill pipe core tube assembly. Background Technology

[0002] Rotary drilling rods play a vital role in the field of engineering construction. With the continuous growth of engineering demands, the torque and number of sections of rotary drilling rods are showing a continuous increasing trend.

[0003] In existing technologies, various core rod structures are employed to strengthen the connection between the core rod and the lower connector. One type of core rod structure utilizes a full-circle wrap around both sides where the lower connector meets the steel pipe to provide reinforcement. This method attempts to enhance the stability of the connection through full-circle wrapping, thereby improving the connection strength to some extent. Another core rod structure uses multiple long reinforcing bars resting against both sides of the lower connector where it meets the steel pipe, hoping to increase the connection strength through the support of these long reinforcing bars.

[0004] However, these existing technologies have significant drawbacks. In structures utilizing a full-circle wrapping, the connection point between the full circle and the key bar is relatively high, close to the torque-bearing point, making the structure prone to stress concentration when subjected to torque. Furthermore, structures employing multiple long reinforcing bars have too many starting and ending points on the steel pipe, not only creating abrupt changes in the cross-section but also easily leading to cracking.

[0005] In summary, how to reduce the stress concentration caused by welding on the overall structure is a problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0006] In view of this, the purpose of this utility model is to provide a connection structure between the drill pipe core tube steel pipe and the lower connector, as well as a drill pipe core tube assembly, which effectively avoids direct connection with the core tube and reduces stress concentration caused by welding to the overall structure.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] A connection structure between a drill pipe core tube steel pipe and a lower connector includes a reinforcing sleeve fitted around the outer periphery of the core tube steel pipe. The lower end face of the reinforcing sleeve forms a first welded joint with the lower connector. The inner circumferential surface of the reinforcing sleeve is provided with an axially extending guide groove group for the key bar to pass through.

[0009] Multiple independent key bars are arranged at intervals along the circumference of the core tube steel pipe. Each key bar has an axial extension section that passes through the reinforcing sleeve. The lower end face of the extension section forms a second welded joint with the lower connector. The reinforcing sleeve and the key bar form a third welded joint.

[0010] Preferably, the reinforcing sleeve includes an annular body, the guide groove group divides the annular body into multiple first ribs and second ribs of different thicknesses, the first ribs are thicker than the second ribs, and the third welded joint is formed between the first ribs and the key strip.

[0011] Preferably, the outer peripheral surface of the annular body is provided with an axially extending welding groove group to expose the connection between the first rib and the key strip.

[0012] Preferably, the side of the first rib is inclined, and the third welded joint is formed at the connection between the side of the first rib and the side of the key strip.

[0013] Preferably, the side of the first rib has a stepped structure, the stepped structure is attached to the side of the key strip away from the core tube steel pipe, and the third welded joint is formed at the connection between the stepped structure and the side of the key strip away from the core tube steel pipe.

[0014] Preferably, there is a gap between the inner surface of the reinforcing sleeve and the outer surface of the core tube steel pipe.

[0015] Preferably, the guide groove group includes at least three guide grooves evenly distributed along the circumference of the annular body, and each guide groove contains at most two key bars.

[0016] Preferably, the welding groove group includes a plurality of welding grooves opened along the circumference of the annular body, and each guide groove has a welding groove extending through both sides.

[0017] A drill pipe core tube assembly employs the aforementioned connection structure between the drill pipe core tube steel pipe and the lower connector.

[0018] Preferably, a spring seat is fitted onto the lower connector, and the spring seat is fixed to the lower connector and arranged coaxially with the core tube steel pipe.

[0019] The connection structure between the drill pipe core tube and the lower connector provided by this utility model avoids the strength problems caused by directly connecting the reinforcing sleeve to the core tube after the reinforcing sleeve is inserted and connected to the key bar and the lower connector. The reinforcing sleeve and the key bar together wrap around the core tube to strengthen it, reducing the cross-sectional change near the connection position of the core tube and the lower connector, and increasing the overall strength in the vicinity. The core tube is not directly welded to the reinforcing sleeve, which reduces the stress concentration problem, and the key bar extends down to connect to the lower connector, keeping the joint away from the torque stress position of the upper section. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 This is a cross-sectional view of the drill pipe core tube assembly in this embodiment;

[0022] Figure 2 This is a schematic diagram of the structure of the first type of reinforcing sleeve in this embodiment;

[0023] Figure 3 This is a schematic diagram of the structure of the second type of reinforcing sleeve in this embodiment;

[0024] Figure 4 This is a schematic diagram of the reinforcing sleeve in this embodiment.

[0025] Figures 1-4 In the accompanying drawings, the reference numerals include:

[0026] 1. Core tube steel pipe; 2. Reinforcing sleeve; 3. Key bar; 4. Guide groove assembly; 5. Lower connector; 6. Welding groove assembly; 7. Spring seat;

[0027] 21. Ring-shaped main body; 22. First rib; 23. Second rib. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this utility model pertains. The terms "first," "second," and similar words used in this utility model do not indicate any order, quantity, or importance. Terms such as "connection" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship can also change accordingly. This application discloses a connection structure between a drill pipe core tube steel pipe and a lower connector, as well as a drill pipe core tube assembly.

[0030] The core of this utility model is to provide a connection structure between the drill rod core tube steel pipe and the lower connector.

[0031] Another core aspect of this utility model is to provide a drill rod core tube assembly, which adopts the connection structure of the drill rod core tube steel pipe and the lower connector described above.

[0032] First, it's important to note that rotary drilling rods are increasingly characterized by higher torque and more sections. Many large-diameter drill rods, such as the 630-6 section model, achieve a torque of 600 kN*M, with an outer rod diameter (D) of 630 mm and a core rod diameter (D) that is often only around 245 mm (slight variations exist between manufacturers). Furthermore, the lower connector (also known as a square head) of the small-diameter steel pipe connection is often used to connect drill bits with diameters of 3 m or even larger. Therefore, the lower connector of the core tube connection is prone to significant abrupt changes in cross-section and stress concentration.

[0033] There are various types of core rod structures in the existing technology. Taking the following two as examples, the first type uses a full ring to protect both sides of the lower connector where it meets the steel pipe, thus providing reinforcement. However, the connection between the full ring and the key bar is relatively high, close to the torque stress point. The second type uses multiple long ribs to reinforce both sides of the lower connector where it meets the steel pipe. However, these long ribs have too many arcing and ending points on the steel pipe, and cause abrupt changes in the cross-section, which easily leads to cracking. Therefore, this application provides a new connection structure between the drill pipe core tube steel pipe and the lower connector to solve the above problems.

[0034] Please refer to Figure 1 .

[0035] The connection structure between the drill core tube steel pipe and the lower connector provided by this utility model includes a reinforcing sleeve 2 sleeved on the outer periphery of the core tube steel pipe 1. The lower end face of the reinforcing sleeve 2 forms a first welded joint with the lower connector 5. The inner circumferential surface of the reinforcing sleeve 2 is provided with an axially extending guide groove group 4 for the key bar 3 to pass through. Multiple independent key bars 3 are arranged at intervals along the circumferential direction of the core tube steel pipe 1. Each key bar 3 is provided with an axially extended section that passes through the reinforcing sleeve 2. The lower end face of the extended section forms a second welded joint with the lower connector 5. The reinforcing sleeve 2 and the key bar 3 form a third welded joint.

[0036] Specifically, the upper side of the lower connector 5 has a stepped structure to facilitate welding with the core tube steel pipe 1, the reinforcing sleeve 2, and the key strip 3. The lower end face of the reinforcing sleeve 2 forms the first welding joint with the lower connector 5, and the inner circumferential surface of the reinforcing sleeve 2 is provided with an axially extending guide groove group 4 (the specific structure is as follows). Figure 4As shown in the diagram, to facilitate the passage of the key bar 3, the key bar 3 has an axial extension section that passes through the reinforcing sleeve. The lower end face of the extension section forms a second welded joint with the lower connector 5, and the reinforcing sleeve 2 and the key bar 3 form a third welded joint. This achieves the effect of reducing the abrupt change in cross-section near the connection position between the core tube steel pipe and the lower connector, while increasing the overall strength in the vicinity and reducing the stress concentration caused by welding on the overall structure. This connection structure avoids direct connection between the reinforcing sleeve 2 and the core tube steel pipe 1, reduces welding on the core tube, thereby reducing stress concentration. Furthermore, the reinforcing sleeve 2 and the key bar 3 together enclose and reinforce the core tube, improving the overall strength.

[0037] The aforementioned connection structure between the drill pipe core tube and the lower connector utilizes the cooperation of the reinforcing sleeve 2 and the key 3 to avoid direct connection between the reinforcing sleeve 2 and the core tube, reducing welding on the core tube and thus minimizing stress concentration caused by welding on the overall structure. Simultaneously, the reinforcing sleeve 2 connects to the key 3 from the outside, effectively encasing and reinforcing the core tube together, reducing abrupt changes in cross-section near the connection point between the core tube 1 and the lower connector 5, and increasing the overall strength in the vicinity.

[0038] The connection structure between the drill core tube steel pipe and the lower connector provided by this utility model will be described in more detail below with reference to the accompanying drawings and specific embodiments.

[0039] In one specific implementation, reference is made to... Figure 2 The reinforcing sleeve 2 includes an annular body 21. The guide groove group 4 divides the annular body 21 into multiple first ribs 22 and second ribs 23 of different thicknesses. The first ribs 22 are thicker than the second ribs 23. The third welded joint is formed between the first ribs 22 and the key strip 3.

[0040] Specifically, the annular body 21 has a circular structure, and its guide groove group 4 is opened on the inner circumferential surface of the annular body 21 to allow the key strip 3 to pass through axially. At the same time, due to the opening of the guide groove group 4, the annular body 21 is divided into two sets of ribs with different thicknesses, namely the thicker first rib 22 and the thinner second rib 23. The key strip 3 is located between two adjacent first ribs 22, and each key strip 3 forms a third welded joint with the adjacent first rib 22.

[0041] Optionally, the annular body 21 is typically made of high-strength steel and has a regular annular shape to ensure stable mounting on the outer circumference of the core tube steel pipe. The first rib 22 can be a rectangular or trapezoidal cross-section, and the second rib 23 can be strip-shaped. The first rib 22 and the second rib 23 are integrally formed to constitute the annular body 21. The guide groove group 4 is an axially extending groove that provides a passage for the key bar to pass through. The guide groove is typically rectangular, and its dimensions need to be designed according to the size of the key bar to ensure smooth passage. The guide groove can be machined onto the annular body 21 or directly formed by casting.

[0042] Based on any of the above embodiments, refer to Figure 2 The outer circumferential surface of the annular body 21 is provided with an axially extending welding groove group 6 so that the connection between the first rib plate 22 and the key strip 3 is exposed.

[0043] Specifically, to facilitate the welding of the key strip 3 to the first rib 22, a welding groove group 6 is provided on the outer periphery of the reinforcing sleeve 2. The welding groove group 6 can be composed of multiple waist-shaped welding grooves. This arrangement exposes the connection between the first rib 22 and the key strip 3, facilitating the welding operation and improving welding quality and efficiency. The welding grooves can be machined onto the outer periphery of the annular body, or their positions can be pre-defined during the casting of the annular body. The length of the waist-shaped holes can be set according to the length of the weld.

[0044] Based on any of the above embodiments, refer to Figure 2 The side of the first rib 22 is inclined, and the third welded joint is formed at the connection between the side of the first rib 22 and the side of the key strip 3.

[0045] Specifically, by welding the first rib 22 to the side of the key strip 3, the inclined side of the first rib 22 allows for better contact between the side of the first rib 22 and the side of the key strip 3. The inclination angle of the first rib 22 can be adjusted according to actual connection requirements, typically between 30° and 60°. This inclined side increases the welding contact area and improves welding strength. The inclination of the first rib 22 can be achieved through machining methods such as milling.

[0046] Based on any of the above embodiments, refer to Figure 3 The first rib 22 has a stepped structure on its side, and the stepped structure is attached to the side of the key strip 3 away from the core tube steel pipe 1. The third welded joint is formed at the connection between the stepped structure and the side of the key strip 3 away from the core tube steel pipe 1.

[0047] Specifically, unlike the side welding method described above, welding to the outside of the key strip 3 can also be used. Due to the thickness difference between the first rib 22 and the second rib 23, a stepped structure is formed on the side of the first rib 22 to accommodate one side of the outer surface of the key strip 3. This allows the outer surface of the key strip 3 to fit snugly against the first rib 22, forming a third welded joint at the connection. The stepped structure can be a single step or multiple steps, and its size and shape need to be designed according to the size of the key strip 3 and the connection requirements. The stepped structure allows for a tighter connection between the first rib 22 and the key strip 3, improving the stability of the connection. The stepped structure can be machined from the side of the first rib 22 using methods such as turning or milling.

[0048] Based on any of the above embodiments, refer to Figure 2 or Figure 3 There is a gap between the inner surface of the reinforcing sleeve 2 and the outer surface of the core tube steel pipe 1. This effectively avoids direct contact between the reinforcing sleeve 2 and the core tube steel pipe 1.

[0049] Based on any of the above embodiments, refer to Figure 2 or Figure 3 The guide groove group 4 includes at least three guide grooves evenly distributed along the circumference of the annular body 21, and each guide groove is provided with at most two key strips 3.

[0050] Specifically, the guide groove group 4 is an axially extending groove that provides a passage for the key bar 3 to pass through. The guide groove is usually fan-shaped, and its size needs to be designed according to the size of the key bar 3 to ensure that the key bar 3 can pass through smoothly. The guide groove can be machined on the annular body 21 or directly formed by casting.

[0051] Based on any of the above embodiments, the welding groove group 6 includes a plurality of welding grooves opened circumferentially along the annular body 21, and welding grooves are opened through both sides of each guide groove.

[0052] Specifically, the welding groove group 6 includes multiple welding grooves circumferentially formed along the annular body 21, with welding grooves extending through both sides of each guide groove. The welding grooves are typically of an oblong shape, and their depth and width need to be designed according to actual welding requirements. This arrangement facilitates the welding operation between the first rib 22 and the key strip 3, improving welding quality and efficiency. The welding grooves can be machined onto the outer circumference of the annular body, or their positions can be pre-defined during the casting of the annular body 21.

[0053] The implementation principle of the connection structure between the drill pipe core tube and the lower connector in this embodiment is as follows: By cooperating with the reinforcing sleeve 2 and the key strip 3, direct connection between the reinforcing sleeve 2 and the core tube 1 is avoided, reducing welding on the core tube and thus reducing stress concentration caused by welding on the overall structure. Simultaneously, the reinforcing sleeve 2 connects to the key strip 3 from the outside, effectively wrapping and reinforcing the core tube together with the key strip 3, reducing abrupt changes in cross-section near the connection point between the core tube 1 and the lower connector 5, and increasing the overall strength in the vicinity. This effectively solves the problem of large abrupt changes in cross-section and stress concentration easily occurring when the core tube is connected to the lower connector 5 in the prior art, improving the overall performance and reliability of the drill pipe core tube. It is suitable for equipment such as rotary drill pipes that require high strength and stability in the connection structure.

[0054] This application also discloses a drill pipe core tube assembly, employing the connection structure between the drill pipe core tube steel pipe and the lower connector as described in the above embodiments. A spring seat 7 is fitted onto the lower connector 5, and the spring seat 7 is fixed to the lower connector 5 and coaxially arranged with the core tube steel pipe 1. The spring seat 7 is typically made of steel with good elasticity, and its shape is annular, allowing for the installation of elastic elements such as springs inside. The function of the spring seat 7 is to buffer the vibration and impact forces generated by the drill pipe during operation, protecting the drill pipe and connecting components. The spring seat 7 can be fixed to the lower connector 5 by welding or bolting. When installing the spring seat 7, it is necessary to ensure that it is coaxially arranged with the core tube steel pipe to ensure uniformity of the buffering effect.

[0055] The implementation principle of this embodiment is as follows: the drill pipe core tube assembly adopts the above-mentioned connection structure, which has the advantages of reducing cross-sectional abrupt changes, stress concentration and enhancing overall strength.

[0056] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0057] The above provides a detailed description of the connection structure between the drill pipe core tube steel pipe and the lower connector, as well as the drill pipe core tube assembly provided by this utility model. Specific examples have been used to illustrate the principle and implementation of this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core idea of ​​this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principle of this utility model, and these improvements and modifications also fall within the protection scope of this utility model.

Claims

1. A connection structure between a drill rod core tube steel pipe and a lower connector, characterized in that, Includes a reinforcing sleeve (2) fitted around the outer periphery of the core tube steel pipe (1), the lower end face of the reinforcing sleeve (2) and the lower connector (5) forming a first welded joint, and the inner periphery of the reinforcing sleeve (2) is provided with an axially extending guide groove group (4) for the key strip (3) to pass through. Multiple independent key bars (3) are arranged at intervals along the circumferential direction of the core tube steel pipe (1). Each key bar (3) is provided with an axial extension section that passes through the reinforcing sleeve (2). The lower end face of the extension section forms a second welded joint with the lower connector (5). The reinforcing sleeve (2) and the key bar (3) form a third welded joint.

2. The connection structure between the drill pipe core tube and the lower connector according to claim 1, characterized in that, The reinforcing sleeve (2) includes an annular body (21), and the guide groove group (4) divides the annular body (21) into multiple first ribs (22) and second ribs (23) of different thicknesses. The first ribs (22) are thicker than the second ribs (23), and the third welded joint is formed between the first ribs (22) and the key strip (3).

3. The connection structure between the drill pipe core tube and the lower connector according to claim 2, characterized in that, The outer circumferential surface of the annular body (21) is provided with an axially extending welding groove group (6) to expose the connection between the first rib (22) and the key strip (3).

4. The connection structure between the drill core tube steel pipe and the lower connector according to claim 3, characterized in that, The side of the first rib (22) is inclined, and the third welded joint is formed at the connection between the side of the first rib (22) and the side of the key strip (3).

5. The connection structure between the drill pipe core tube and the lower connector according to claim 3, characterized in that, The first rib (22) has a stepped structure on its side, which is attached to the side of the key strip (3) away from the core tube steel pipe (1). The third welded joint is formed at the connection between the stepped structure and the side of the key strip (3) away from the core tube steel pipe (1).

6. The connection structure between the drill pipe core tube and the lower connector according to claim 1, characterized in that, There is a gap between the inner surface of the reinforcing sleeve (2) and the outer surface of the core tube steel pipe (1).

7. The connection structure between the drill pipe core tube and the lower connector according to claim 3, characterized in that, The guide groove group (4) includes at least three guide grooves evenly distributed along the circumference of the annular body (21), and each guide groove is provided with at most two key bars (3).

8. The connection structure between the drill pipe core tube and the lower connector according to claim 7, characterized in that, The welding groove group (6) includes a plurality of welding grooves opened circumferentially along the annular body (21), and each guide groove has a welding groove through both sides.

9. A drill pipe core tube assembly, characterized in that, The connection structure between the drill core tube steel pipe and the lower connector as described in any one of claims 1-8 is adopted.

10. The drill pipe core tube assembly according to claim 9, characterized in that, A spring seat (7) is fitted on the lower connector (5). The spring seat (7) is fixed to the lower connector (5) and arranged coaxially with the core tube steel pipe (1).

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