Heterogeneous pipe connecting structure for transmitting load

Abstract

The invention discloses a heterogeneous pipe connecting structure for transmitting loads. The heterogeneous pipe connecting structure comprises a composite pipe, a front connector, a rear connector, a front auxiliary connector and a rear auxiliary connector. The front joint comprises a front joint external thread section and a front joint bonding section; a front joint inner bonding cavity, a front joint inner thread cavity and a front joint cavity are formed in the front joint; the rear joint comprises a rear joint body, a rear joint internal thread cavity, a rear joint transition cavity, a rear joint internal fine thread cavity and a rear joint bonding cavity; the outer surface of the composite pipe is bonded with the metal joint, the inner surface of the composite pipe is bonded with the metal auxiliary joint, and the joint and the auxiliary joint form an integral structure through the fine threads, so that the bonding area of the composite pipe and the metal joint is increased, and the bonding strength is improved. A plurality of annular grooves are formed in the bonding surfaces of the front joint, the front auxiliary joint, the rear joint and the rear auxiliary joint of the metal part, so that the uniformity of a bonding agent is effectively improved, and the bonding sealing performance of the composite pipe and the metal joint is improved after secondary bonding.

Description

A heterogeneous tubular connection structure for transmitting loads Technical Field

[0001] This invention belongs to the field of advanced manufacturing and joining technology of composite materials, and specifically relates to a heterogeneous tubular connection structure for transmitting loads. Background Technology

[0002] Composite materials made of carbon fiber, glass fiber, and organic fiber are used as outer tubes for measurement-while-drilling (MSD) and logging-while-drilling (LOD) instruments. This not only reduces the weight of the drill string in directional drilling operations such as oil exploration and development, coal mine gas and water hazard control, and advanced geological exploration, but also solves the problem of electromagnetic signal penetration transmission for specialized measuring instruments. In existing product structures, the instrument outer tube, made of composite materials, is permanently connected at both ends to threaded metal joints to form an outer tube short section. During construction, the measuring instrument is axially and circumferentially fixed through special positioning mechanisms on the inner walls of the metal joints at both ends of this outer tube short section. The outer tube short section is connected to other metal drill pipes in the drill string via threads at both ends of the metal joints, enabling MSD and MOD. Under drilling conditions, the instrument outer tube short section needs to transmit the axial load and torque applied by the drilling rig at the drill bit side, and withstand additional bending moments and vibrations caused by borehole bending.

[0003] Currently, the main heterogeneous connection methods between composite materials and metal steel are adhesive bonding or mechanical bonding, or a combination of both.

[0004] The advantages of adhesive bonding are that there is no stress concentration caused by drilling at the joint, no significant increase in the weight of the joint structure, high connection efficiency, good sealing performance, and prevention of crack propagation. However, it usually requires the adhesive to have good toughness, strict requirements for curing temperature and pressure, good compatibility with the bonded parts, and high precision of the mating surfaces. Moreover, the adhesive performance is greatly affected by the environment, it is prone to aging, has low peel strength, and is difficult to transfer large loads.

[0005] Mechanical connection methods have the advantages of being easy to disassemble, interchangeable, having good anti-peeling performance, being less affected by the environment, and having no residual stress inside the connection, making them suitable for high-intensity and high-load working conditions; however, the connection structure has poor sealing performance, and stress concentration is easily generated around the opening, which will significantly increase the overall weight of the structure.

[0006] Theoretical calculations and field applications show that the permanent connection between the composite material tube body and the steel joint of the instrument's outer tube is the weakest link in the entire structure, prone to failure behaviors such as peeling, debonding, and breakage during drilling. For heterogeneous materials in tube-to-tube structures, the structural strength and efficiency of the aforementioned adhesive or mechanical connections are insufficient to ensure the effective transfer of the loads necessary for drilling operations.

[0007] As can be seen from the above, the heterogeneous connection structure between the composite pipe and the steel joint needs to transmit axial tensile, compressive, and torsional loads, and overcome the bending stress and vibration caused by the drilling trajectory. Existing structures and processing technologies cannot achieve efficient and reliable connection. Summary of the Invention

[0008] In view of the above-mentioned shortcomings and defects of the prior art, the purpose of this invention is to provide a heterogeneous pipe connection structure for transmitting loads, which solves the problem that it is difficult to simultaneously guarantee the bonding strength, reliable load transmission, fatigue resistance, corrosion resistance and sealing performance when using pure adhesive or pure mechanical connection processes between composite pipes and metal joints in the prior art.

[0009] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0010] A heterogeneous tubular connection structure for transmitting loads includes a composite pipe, and a front connector and a rear connector sleeved at both ends of the composite pipe.

[0011] A front auxiliary connector is also sleeved on the inner side between the composite pipe and the front connector, and a rear auxiliary connector is also sleeved on the inner side between the composite pipe and the rear connector.

[0012] The aforementioned front connector is a hollow cylindrical shape, comprising a coaxially connected external threaded section and an adhesive section.

[0013] The front connector has a coaxially connected bonding cavity, a threaded cavity, and a hollow cavity inside.

[0014] The aforementioned front connector adhesive section is bonded to the outer side of the end of the composite pipe.

[0015] The rear connector is a hollow cylinder, including a rear connector body, and also includes a rear connector internal thread cavity, a rear connector transition cavity, a rear connector internal fine thread cavity and a rear connector bonding cavity arranged coaxially inside the rear connector body.

[0016] The aforementioned rear connector adhesive cavity is bonded to the outer side of the other end of the composite pipe.

[0017] The aforementioned front auxiliary connector is a hollow cylindrical shape, comprising a coaxially connected external threaded section and an adhesive section.

[0018] The external thread section of the front auxiliary connector mates with the internal thread cavity of the front connector, and the adhesive section of the front auxiliary connector extends into the composite pipe and is adhesively bonded to the composite pipe.

[0019] The aforementioned rear auxiliary connector is a hollow cylindrical shape, comprising a coaxially connected external threaded section and an adhesive section.

[0020] The external thread section of the rear auxiliary connector mates with the fine thread cavity inside the rear connector, and the adhesive section of the rear auxiliary connector extends into the composite pipe and is bonded to the composite pipe.

[0021] The present invention also has the following technical features: the inner bonding cavity and the inner threaded cavity of the front connector are located inside the bonding section of the front connector, and the cavity of the front connector is located inside the outer threaded section and the bonding section of the front connector.

[0022] The diameter of the external thread section of the front connector is smaller than the diameter of the adhesive section of the front connector.

[0023] The diameters of the inner adhesive cavity, the inner threaded cavity, and the hollow cavity of the front connector decrease sequentially.

[0024] The front connector inner bonding cavity sidewall is also provided with multiple annular front connector grooves.

[0025] The diameter of the transition cavity of the rear connector is smaller than the diameter of the internal thread cavity and the fine thread cavity of the rear connector.

[0026] The diameter of the bonding cavity of the rear connector is larger than the diameter of the fine thread cavity inside the rear connector.

[0027] The rear connector bonding cavity sidewall is also provided with multiple annular rear connector grooves.

[0028] The outer walls of the front auxiliary joint bonding section and the rear auxiliary joint bonding section are also provided with multiple annular auxiliary joint grooves.

[0029] The open end of the bonding cavity in the front connector and the bonding cavity in the rear connector is set as a conical surface.

[0030] The composite pipe includes a front connecting section, a first conical section, a composite pipe body section, a second conical section, and a rear connecting section that are coaxially connected in sequence.

[0031] The front connector adhesive section is bonded to the outer side of the end of the front connecting section, and the conical surface is in contact with the first conical surface section.

[0032] The rear connector adhesive cavity is bonded to the outer side of the rear connecting section end, and the conical surface is fitted with the second conical surface section.

[0033] The aforementioned front auxiliary connector adhesive section extends into the front connecting section and is adhesively bonded to the front connecting section.

[0034] The aforementioned auxiliary connector adhesive section extends into the rear connecting section and is bonded to the rear connecting section.

[0035] Both the front connector bonding section and the front connecting section have through holes, and the front auxiliary connector bonding section has blind holes. The through holes and blind holes are positioned correspondingly, and the blind holes are threaded. Fasteners are also installed in the through holes and blind holes.

[0036] Both the rear connector bonding section and the rear connecting section have through holes, and the rear auxiliary connector bonding section has blind holes. The through holes and blind holes are positioned correspondingly and are threaded. Fasteners are also installed in the through holes and blind holes.

[0037] Compared with the prior art, the beneficial technical effects of the present invention are: (I) The outer surface of the composite pipe of the present invention is bonded to the metal joint, and the inner surface is bonded to the metal auxiliary joint. The joint and the auxiliary joint form an integral structure through fine thread, which increases the bonding area between the composite pipe and the metal joint, thereby improving the bonding strength.

[0038] (II) The bonding surfaces of the front joint, front auxiliary joint, rear joint and rear auxiliary joint of the metal parts of the present invention are processed with multiple annular grooves, which effectively improves the uniformity of the adhesive and improves the sealing performance of the composite pipe and the metal joint after secondary bonding.

[0039] (III) The lateral fastener of the present invention connects the metal joint, the composite pipe and the metal auxiliary joint to form an integral structure. The adhesive and the fastener jointly bear the axial load and torque of the connection structure, and the connection strength is improved for a second time, which can meet the performance requirements of drilling construction for short-connection of external pipe.

[0040] (IV) The end of the outer bonding surface of the composite pipe of the present invention is provided with a conical transition structure, so that the ends of the joint and the auxiliary joint are staggered by a certain length along the axial direction, thereby avoiding the abrupt change in the cross-sectional stiffness of the connection structure along the axial direction, thus enhancing the bending resistance of the overall structure.

[0041] (V) The composite pipe and metal joint of the present invention for transmitting load have a clever structure, simple processing technology and strong operability.

[0042] (VI) The overall structure of this invention has a tensile strength of 96.7T and a torsional strength of 20.2kNm, while the conventional tensile strength is 36T and the torsional strength is 5000Nm, which significantly improves the load-bearing performance. Attached Figure Description

[0043] Figure 1 is a schematic diagram of the overall structure of the heterogeneous tubular connection structure for transmitting loads according to this application.

[0044] Figure 2 is a schematic diagram of the overall structure of the composite pipe of this application.

[0045] Figure 3 is a schematic diagram of the overall structure of the front connector of this application.

[0046] Figure 4 is a schematic diagram of the overall structure of the rear connector of this application.

[0047] Figure 5 is a schematic diagram of the overall structure of the front auxiliary connector of this application.

[0048] The meanings of the labels in the attached diagram are as follows: 1-composite pipe, 2-front connector, 3-rear connector, 4-front auxiliary connector, 5-rear auxiliary connector, 6-blind hole, 7-fastener.

[0049] 1-1-Front connecting section, 1-2-First conical section, 1-3-Composite pipe body section, 1-4-Second conical section, 1-5-Rear connecting section.

[0050] 2-1- External threaded section of front connector, 2-2- Adhesive section of front connector, 2-3- Inner adhesive cavity of front connector, 2-4- Inner threaded cavity of front connector, 2-5- Hollow cavity of front connector, 2-6- Ring groove of front connector.

[0051] 3-1- Rear connector body, 3-2- Rear connector internal thread cavity, 3-3- Rear connector transition cavity, 3-4- Rear connector internal fine thread cavity, 3-5- Rear connector bonding cavity, 3-6- Rear connector annular groove.

[0052] 4-1- External thread section of front auxiliary connector, 4-2- Adhesive section of front auxiliary connector, 4-3 Ring groove of auxiliary connector.

[0053] The specific content of the present invention will be further explained in detail below with reference to the embodiments. Detailed Implementation

[0054] It should be noted that, unless otherwise specified, all components in this invention are components known in the prior art.

[0055] 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.

[0056] Example 1: A heterogeneous pipe connection structure for transmitting loads, as shown in Figures 1-5, includes a composite pipe 1, and a front connector 2 and a rear connector 3 sleeved at both ends of the composite pipe 1.

[0057] A front auxiliary connector 4 is sleeved on the inner side between the composite pipe 1 and the front connector 2, and a rear auxiliary connector 5 is sleeved on the inner side between the composite pipe 1 and the rear connector 3.

[0058] The front connector 2 is a hollow cylinder, comprising a coaxially connected external thread section 2-1 and an adhesive section 2-2.

[0059] The front connector 2 has a coaxially connected bonding cavity 2-3, a threaded cavity 2-4, and a hollow cavity 2-5 inside.

[0060] The aforementioned front connector adhesive section 2-2 is bonded to the outer side of the end of the composite pipe 1.

[0061] The front connector 2 is made of tempered alloy steel, and the threaded part is subjected to nitriding surface strengthening process.

[0062] The external thread section 2-1 of the front connector is used to connect with the internal threads of other drill pipes in the drill string. The internal thread cavity 2-4 of the front connector mates with the external thread section 4-1 of the front auxiliary connector 4 to realize the connection and positioning of the composite pipe 1 and the front connector 2. The internal adhesive cavity 2-3 of the front connector contains multiple annular front connector grooves 2-6, which are used to adhesively fit with the composite pipe 1.

[0063] The rear connector 3 is a hollow cylinder, including a rear connector body 3-1, and also includes a rear connector internal thread cavity 3-2, a rear connector transition cavity 3-3, a rear connector internal fine thread cavity 3-4, and a rear connector bonding cavity 3-5, which are coaxially connected and arranged inside the rear connector body 3-1.

[0064] The rear connector bonding cavity 3-5 is bonded to the outer side of the other end of the composite pipe 1.

[0065] The rear connector 3 is made of tempered alloy steel, and the threaded part is subjected to nitriding surface strengthening process.

[0066] The internal threaded cavity 3-2 of the rear connector is used to connect with the external threads of other drill rods in the drill string. The fine threaded cavity 3-4 of the rear connector mates with the external threaded section of the rear auxiliary connector 5 to realize the connection and positioning of the composite tube 1 and the rear connector 3. The adhesive cavity 3-5 of the rear connector contains multiple annular rear connector grooves 3-6, which are used to adhesively fit with the composite tube 1.

[0067] The aforementioned front auxiliary connector 4 is a hollow cylinder, comprising a coaxially connected external thread section 4-1 and an adhesive section 4-2.

[0068] The external thread section 4-1 of the front auxiliary connector mates with the internal thread cavity 2-4 of the front connector, and the adhesive section 4-2 of the front auxiliary connector extends into the composite pipe 1 and is adhesively bonded to the composite pipe 1.

[0069] The rear auxiliary connector 5 is a hollow cylinder, comprising a coaxially connected external thread section and an adhesive section.

[0070] The external thread section of the rear auxiliary connector mates with the fine thread cavity 3-4 inside the rear connector, and the adhesive section of the rear auxiliary connector extends into the composite pipe 1 and is adhesively bonded to the composite pipe 1.

[0071] The adhesive is evenly applied to the bonding surfaces of the composite pipe 1, the front auxiliary connector 4, and the front connector 2, and the positioning connection is completed. The pipe is then placed in an insulation device to complete the secondary bonding and curing. The curing temperature of the secondary bonding is 30-50℃ lower than the curing temperature of the composite pipe 1.

[0072] As a preferred embodiment, the inner bonding cavity 2-3 and the inner threaded cavity 2-4 of the front connector are located inside the bonding section 2-2 of the front connector, and the cavity 2-5 of the front connector is located inside the outer threaded section 2-1 and the bonding section 2-2 of the front connector.

[0073] The diameter of the external thread section 2-1 of the front connector is smaller than the diameter of the adhesive section 2-2 of the front connector.

[0074] The diameters of the inner bonding cavity 2-3, the inner threaded cavity 2-4, and the hollow cavity 2-5 of the front connector decrease sequentially.

[0075] The front connector inner bonding cavity 2-3 is also provided with multiple annular front connector grooves 2-6 on its side wall to store adhesive and ensure the uniformity and sealing of the bonding structure.

[0076] As a preferred embodiment, the diameter of the transition cavity 3-3 of the rear connector is smaller than the diameter of the internal thread cavity 3-2 and the fine thread cavity 3-4 of the rear connector.

[0077] The diameter of the bonding cavity 3-5 of the rear connector is larger than the diameter of the fine thread cavity 3-4 inside the rear connector.

[0078] The rear connector bonding cavity 3-5 is also provided with multiple annular rear connector grooves 3-6 on its side wall to store adhesive and ensure the uniformity and sealing of the bonding structure.

[0079] As a preferred embodiment, the outer walls of the front auxiliary joint bonding section 4-2 and the rear auxiliary joint bonding section are further provided with multiple annular auxiliary joint grooves 4-3.

[0080] As a preferred embodiment, the open end of the front connector inner bonding cavity 2-3 and the rear connector bonding cavity 3-5 is set as a conical surface.

[0081] As a preferred embodiment, the composite pipe 1 includes a front connecting section 1-1, a first conical section 1-2, a composite pipe body section 1-3, a second conical section 1-4, and a rear connecting section 1-5, which are coaxially connected in sequence.

[0082] The front connector adhesive section 2-2 is bonded to the outer side of the end of the front connecting section 1-1, and the conical surface is in contact with the first conical surface section 1-2.

[0083] The rear connector bonding cavity 3-5 is bonded to the outer side of the end of the rear connecting section 1-5, and the conical surface is in contact with the second conical surface section 1-4.

[0084] The front auxiliary connector adhesive section 4-2 extends into the front connecting section 1-1 and is bonded to the front connecting section 1-1.

[0085] The auxiliary connector adhesive section extends into the rear connecting section 1-5 and is bonded to the rear connecting section 1-5.

[0086] Composite pipe 1 is made of fiber-reinforced resin matrix composite material. It is formed by rolling or winding and then heating and curing. When winding, the winding angle is 20°-60° to give full play to the uniaxial tensile strength of the fiber and simultaneously improve the pipe body's ability to withstand axial load and torque.

[0087] The reinforcing material includes untwisted rovings made of carbon fiber, glass fiber, quartz fiber, PBO fiber, etc., with a diameter range of 5-20mm; the resin matrix material includes epoxy resin, polyurethane, acrylic acid, etc.

[0088] The composite pipe is heated and cured at a temperature of 150-200℃, and the heat preservation time is 4-8 hours.

[0089] After the composite pipe is cured and formed, an inner and outer bonding surface structure that matches the front connector 2 and the front auxiliary connector 4 is processed at one end of the composite pipe, and an inner and outer bonding surface structure that matches the rear connector 3 and the rear auxiliary connector 5 is processed at the other end.

[0090] A tapered transition structure is provided at the end of the outer bonding surface of the composite pipe. This transition structure makes the ends of the joint and the auxiliary joint offset along the axis by a certain length, ensuring that the cross-sectional stiffness of the metal joint and the composite pipe transitions smoothly along the axis.

[0091] As a preferred embodiment, both the front connector bonding section 2-2 and the front connecting section 1-1 have through holes, and the front auxiliary connector bonding section 4-2 has a blind hole 6. The through holes and blind holes 6 are positioned correspondingly, and the blind holes 6 are threaded. Fasteners 7 are also installed in the through holes and blind holes 6.

[0092] Both the rear connector bonding section and the rear connecting section 1-5 have through holes, and the rear auxiliary connector bonding section has blind holes 6. The through holes and blind holes 6 are positioned correspondingly and are threaded. Fasteners 7 are also installed in the through holes and blind holes 6.

[0093] The number of blind holes 6 shall not be less than two, and the diameter of the blind holes shall not exceed 20 mm, in order to prevent destructive damage to the overall structure of the composite material.

[0094] Lateral fasteners 7 are installed inside the blind hole. The fasteners 7 are engaged with the fine threads of the through hole through fine threads. The fasteners 7 and the adhesive work together to enhance the connection strength between the composite pipe 1 and the front connector 2 and the rear connector 3.

[0095] Example 2: A Φ89 tube with a wall thickness of 15mm was prepared using a quartz fiber composite material by winding. After heating and curing, a mandrel was removed to form composite tube 1. The quartz fiber diameter was 15mm, the winding angle was 45°, and the resin was epoxy resin. The composite tube 1 was cured at 180℃ for 6 hours.

[0096] This embodiment provides a heterogeneous pipe connection process for transmitting loads, including: Step 1: using quartz fiber winding and heating to cure to form a composite pipe 1, the structure of which is shown in Figure 2. At one end of the composite pipe 1, a front connecting section 1-1 and a first conical section 1-2 that cooperate with the front connector 2 and the front auxiliary connector 4 are processed, and at the other end, a second conical section 1-4 and a rear connecting section 1-5 that cooperate with the rear connector 3 and the rear auxiliary connector 5 are processed.

[0097] Step 2: Use tempered alloy steel to process the front connector 2 and the rear connector 3. The structures of the front connector 2 and the rear connector 3 are shown in Figure 3 and Figure 4, respectively. After processing, the threaded part is strengthened by surface nitriding.

[0098] Step 3: Use alloy steel to process the front auxiliary connector 4 and the rear auxiliary connector 5. The structure of the front auxiliary connector 4 and the rear auxiliary connector 5 is shown in Figure 5.

[0099] Step 4: Apply adhesive to the auxiliary joint annular groove 4-3, and fit the front connecting section 1-1 and the rear connecting section 1-5 onto the outside of the front auxiliary joint 4 and the rear auxiliary joint 5 respectively.

[0100] Step 5: Apply adhesive to the bonding cavity 2-3, the annular groove 2-6, the bonding cavity 3-5, and the annular groove 3-6 of the front connector, respectively. Connect the front connector 2 and the rear connector 3 to both ends of the composite pipe 1, ensuring that the internal thread cavity 2-4 of the front connector and the external thread section 4-1 of the front auxiliary connector, and the internal thread cavity 3-2 of the rear connector and the external thread section of the rear auxiliary connector, respectively, are tightly fitted. Place the assembled connectors into the heat preservation device to complete the secondary bonding and curing. The curing temperature of the secondary bonding is 30-50℃ lower than the curing temperature of the composite pipe.

[0101] Step 6: At the midpoint of the bonding area between the front connector 2 and the rear connector 3, machine three sets of Φ20mm holes evenly distributed along the circumference. The holes pass through the front connector 2, the composite pipe 1, and the front auxiliary connector 4, forming a blind hole 6 on the front auxiliary connector 4. The holes pass through the rear connector 3, the composite pipe 1, and the rear auxiliary connector 5, forming a blind hole 6 on the rear auxiliary connector 5. The depth of the blind hole 6 is not less than 3mm, and fine threads are machined on it.

[0102] Step 7: Install the lateral fastener 7 at the location of blind hole 6. The thread of fastener 7 should fit tightly with the fine thread of blind hole 6 to complete the installation of all structures. The fastener and adhesive work together to enhance the connection strength between the composite pipe and the metal joint.

[0103] 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 heterogeneous tubular connection structure for transmitting loads, comprising a composite pipe (1), characterized in that, It also includes a front connector (2) and a rear connector (3) sleeved at both ends of the composite pipe (1); a front auxiliary connector (4) is sleeved on the inner side between the composite pipe (1) and the front connector (2), and a rear auxiliary connector (5) is sleeved on the inner side between the composite pipe (1) and the rear connector (3); the front connector (2) is a hollow cylinder, including a front connector external thread section (2-1) and a front connector adhesive section (2-2) coaxially connected; the front connector (2) has a front connector inner adhesive cavity (2-3), a front connector inner thread cavity (2-4), and a front connector cavity (2-5) coaxially connected inside; the front connector adhesive section (2-2) is bonded to the outer side of the end of the composite pipe (1); the rear connector (3) is a hollow cylinder, including a rear connector body (3-1), and also includes a rear connector inner thread cavity (3-2) coaxially connected inside the rear connector body (3-1). The rear auxiliary connector (4) is a hollow cylindrical joint, comprising a coaxially connected external thread section (4-1) and an internal fine thread section (2-4) and a bonding section (4-2) of the rear auxiliary connector. The external thread section (4-1) of the rear auxiliary connector mates with the internal thread section (2-4) of the rear auxiliary connector, and the bonding section (4-2) of the rear auxiliary connector extends into the composite pipe (1) and is bonded to the composite pipe (1). The rear auxiliary connector (5) is a hollow cylindrical joint, comprising a coaxially connected external thread section and a bonding section of the rear auxiliary connector. The external thread section of the rear auxiliary connector mates with the internal fine thread section (3-4) of the rear auxiliary connector, and the bonding section of the rear auxiliary connector extends into the composite pipe (1) and is bonded to the composite pipe (1).

2. The heterogeneous tubular connection structure for transmitting loads as described in claim 1, characterized in that, The inner bonding cavity (2-3) and the inner threaded cavity (2-4) of the front connector are located inside the bonding section (2-2) of the front connector, and the cavity (2-5) of the front connector is located inside the outer threaded section (2-1) and the bonding section (2-2) of the front connector; the diameter of the outer threaded section (2-1) of the front connector is smaller than the diameter of the bonding section (2-2) of the front connector; the diameters of the inner bonding cavity (2-3), the inner threaded cavity (2-4), and the cavity (2-5) of the front connector decrease sequentially; a plurality of annular grooves (2-6) of the front connector are also provided on the side wall of the inner bonding cavity (2-3).

3. The heterogeneous tubular connection structure for transmitting loads as described in claim 2, characterized in that, The diameter of the transition cavity (3-3) of the rear connector is smaller than the diameter of the internal thread cavity (3-2) and the fine thread cavity (3-4) of the rear connector; the diameter of the bonding cavity (3-5) of the rear connector is larger than the diameter of the fine thread cavity (3-4) of the rear connector; and multiple annular grooves (3-6) of the rear connector are also provided on the side wall of the bonding cavity (3-5).

4. The heterogeneous tubular connection structure for transmitting loads as described in claim 3, characterized in that, The outer walls of the front auxiliary joint bonding section (4-2) and the rear auxiliary joint bonding section are also provided with multiple annular auxiliary joint grooves.

5. The heterogeneous pipe connection structure for transmitting load as described in claim 4, wherein in step four, the open end of the front joint inner bonding cavity (2-3) and the rear joint bonding cavity (3-5) is set as a conical surface.

6. The heterogeneous pipe connection structure for transmitting load as described in claim 5, wherein in step four, the composite pipe (1) comprises a front connecting section (1-1), a first conical section (1-2), a composite pipe body section (1-3), a second conical section (1-4), and a rear connecting section (1-5) connected coaxially in sequence; the front joint bonding section (2-2) is bonded to the outer side of the end of the front connecting section (1-1), and the conical surface is in contact with the first conical section (1-2); the rear joint bonding cavity (3-5) is bonded to the outer side of the end of the rear connecting section (1-5), and the conical surface is in contact with the second conical section (1-4); the front auxiliary joint bonding section (4-2) extends into the front connecting section (1-1) and is bonded to the front connecting section (1-1); the rear auxiliary joint bonding section extends into the rear connecting section (1-5) and is bonded to the rear connecting section (1-5).

7. The heterogeneous pipe connection structure for transmitting load as described in claim 1, in step four, the front joint bonding section (2-2) and the front connecting section (1-1) are both provided with through holes, the front auxiliary joint bonding section (4-2) is provided with blind holes (6), the through holes and blind holes (6) are corresponding in position and the blind holes (6) are threaded, and fasteners (7) are also installed in the through holes and blind holes (6); the rear joint bonding section and the rear connecting section (1-5) are both provided with through holes, the rear auxiliary joint bonding section is provided with blind holes (6), the through holes and blind holes (6) are corresponding in position and the through holes and blind holes (6) are threaded, and fasteners (7) are also installed in the through holes and blind holes (6).

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