Bimetal composite pipe and synchronous extrusion forming machine thereof

Abstract

The invention relates to the technical field of composite metal pipes, in particular to a bimetal composite pipe and a synchronous extrusion forming machine thereof. A plurality of protrusions extending in the axial direction are annularly arranged on the outer wall of the inner pipe at equal intervals. Grooves matched with the protrusions in shape, number and distribution are formed in the inner wall of the outer pipe. And the bulge can be embedded with the groove. Double mechanical connection is formed through circumferential interlocking of the protrusions and the grooves and axial locking of the notches and the inserting blocks, interlayer relative displacement is effectively prevented, and the bearing reliability of the composite pipe is improved. In the manufacturing process, zero-sliding clamping is achieved through the adaptive design of the clamping jaws and the pipe notches, and the inserting precision is ensured; a double-assembly alternate relay mode breaks through stroke limitation, and continuous and efficient forming of long-size pipes is achieved; the belt-torsion spring posture adjusting mechanism enables the clamp to automatically rotate and avoid, so that the space interference is solved, and the automation degree is improved; and the whole plugging process is stable and controlled.

Description

Technical Field

[0001] This invention relates to the field of composite metal pipe technology, and in particular to a bimetallic composite pipe and its synchronous extrusion molding machine. Background Technology

[0002] In the manufacturing of bimetallic composite tubes, existing technologies typically employ a process of separate fabrication and reassembly. Specifically, the inner and outer tubes are first processed into independent tubes of predetermined dimensions. Then, through mechanical expansion, cold drawing, or hydraulic expansion, the inner tube is inserted into the outer tube, or the outer tube is fitted over the inner tube. Plastic deformation allows the two tube walls to achieve a metallurgical or mechanical bond through interference fit, thus forming a composite tube structure. This method has relatively clear process steps and lower requirements for the initial state of the two metal materials, especially the smoothness of the inner and outer surfaces of the tubes, facilitating preliminary assembly and insertion.

[0003] However, the aforementioned existing methods have significant drawbacks. Since the inner and outer tubes are smooth, independent entities before joining, even though the initial insertion stage is relatively convenient, in subsequent joining processes and the final product's use, the two tubes rely solely on the friction generated by the interference fit to prevent relative movement. This joining method is highly susceptible to axial misalignment or circumferential rotation between the inner and outer tubes when subjected to axial forces, torsional loads, or drastic temperature changes. This disrupts the uniformity and stability of the joint, affecting the overall mechanical properties, dimensional accuracy, and long-term reliability of the composite tube. Therefore, there is an urgent need for a novel structure that can fundamentally enhance the bonding strength and displacement resistance between the two metal layers, along with a matching efficient forming method. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is that the existing bimetallic composite tubes, because both the inner and outer tubes are smooth surfaces, rely only on the frictional force of the interference fit, which makes it easy for the interlayer to misalign or rotate when subjected to force, resulting in insufficient bonding stability.

[0005] The above-mentioned technical problems are solved by the following technical solution: The present invention proposes a bimetallic composite tube, including an outer tube and an inner tube; the outer wall of the inner tube is provided with a plurality of axially extending protrusions at equal intervals in a ring; the inner wall of the outer tube is provided with grooves that match the shape, number and distribution of the protrusions; the protrusions can fit into the grooves.

[0006] In a preferred embodiment of the bimetallic composite tube of the present invention: the outer tube has a plurality of first notches spaced apart along its axial direction on its wall; the inner tube has a plurality of second notches spaced apart along its axial direction on its wall; when the protrusion engages with the groove and the inner tube and the outer tube reach a predetermined insertion position, the corresponding first notch and second notch overlap radially to form an insert; an insert block is disposed in the insert.

[0007] The above-mentioned technical problems are solved by the following technical solution: The present invention also proposes a bimetallic composite tube synchronous extrusion molding machine for preparing the bimetallic composite tube, which includes a base plate and a first moving extrusion assembly and a second moving extrusion assembly arranged side by side on the base plate; the first moving extrusion assembly and the second moving extrusion assembly each include a first driving unit, a guiding unit and two clamping members; the first driving unit is used to drive the two clamping members to move towards or away from each other along the guiding unit; each clamping member is provided with a clamp for clamping the tube.

[0008] In a preferred embodiment of the bimetallic composite tube synchronous extrusion molding machine of the present invention: the first driving unit includes a first double-ended lead screw and a first motor that drives the first double-ended lead screw to rotate; the guiding unit includes a guide rail arranged parallel to the first double-ended lead screw; the clamping member includes a guide seat that slides with the guide rail, a screw seat that threads with the first double-ended lead screw, and a fixing plate that connects the guide seat and the screw seat.

[0009] In a preferred embodiment of the bimetallic composite tube synchronous extrusion molding machine of the present invention: the clamp includes a fixed arm, a second double-ended lead screw disposed on the fixed arm, a second motor for driving the second double-ended lead screw to rotate, and two clamping seats that respectively engage with the two threaded sections of the second double-ended lead screw; each clamping seat is provided with a clamping claw.

[0010] In a preferred embodiment of the bimetallic composite tube synchronous extrusion molding machine of the present invention: a hinge seat is provided on the fixed plate, and the clamp is mounted on the fixed plate through the hinge seat; the hinge seat includes a support ring connected to the fixed plate, a rotating ring connected to the clamp, and a rotating shaft connecting the support ring and the rotating ring; an elastic element is provided on the rotating shaft to give it a reset tendency.

[0011] In a preferred embodiment of the bimetallic composite tube synchronous extrusion molding machine of the present invention, it further includes a posture adjustment mechanism; the posture adjustment mechanism includes a roller disposed between the guide seat and the screw seat, and a transmission component connecting the roller and the rotating shaft.

[0012] In a preferred embodiment of the bimetallic composite tube synchronous extrusion molding machine of the present invention: the thickness of the gripper is configured to match the shape of the groove on the outer wall of the tube to be clamped.

[0013] In a preferred embodiment of the bimetallic composite tube synchronous extrusion molding machine of the present invention: the cross-section of the protrusion and the groove is trapezoidal; the cross-section of the first notch, the second notch and the insert block is also trapezoidal.

[0014] In a preferred embodiment of the bimetallic composite tube synchronous extrusion molding machine of the present invention, the following steps are included: the two clamping members of the first moving extrusion assembly clamp the outer tube and the inner tube respectively, and move towards each other under the drive of the first driving unit, so that a portion of the length of the inner tube is inserted into the outer tube, completing the first segment insertion; subsequently, the clamping members of the first moving extrusion assembly release the tube and reset, during which the clamp rotates to an avoidance posture under the action of the posture adjustment mechanism; the two clamping members of the second moving extrusion assembly clamp the outer tube and the inner tube that have completed the first segment insertion respectively, and drive them to continue moving towards each other, completing the second segment insertion; the above steps are repeated alternately until the inner tube and the outer tube are completely inserted into place; the insert block is inserted into the groove formed by the overlapping first notch and the second notch.

[0015] The beneficial effects of this invention are as follows: At the product structure level, the composite pipe provided by this invention forms a direct mechanical interlock in the circumferential direction by setting mutually interlocking axial protrusions and grooves on the mating surfaces of the inner and outer pipes. This structure fundamentally changes the traditional friction-dependent bonding method. When the pipe body is subjected to torque, the sidewalls of the protrusions and grooves abut against each other, effectively preventing relative rotation between layers. Simultaneously, by setting overlapping first and second notches at corresponding positions on the outer and inner pipes, and inserting a block into the overlapping notch, axial mechanical locking is achieved. The block simultaneously engages within the notches of the inner and outer pipes, acting like a transverse pin, preventing relative axial movement between the inner and outer pipes. This dual mechanical locking structure, combining "protrusion-groove" and "notch-block," constrains relative displacement from two orthogonal directions, thereby significantly improving the torsional strength, axial load-bearing capacity, and overall structural reliability of the composite pipe.

[0016] At the manufacturing equipment and process level: First, regarding precise positioning and reliable clamping: The clamping jaws of the forming machine are relatively thin, making it easy to insert into the notches on the tube. This allows the jaws to embed into the notches during clamping, forming a shape fit rather than relying solely on friction. This design ensures that there is no relative slippage between the jaws and the tube when a huge axial insertion force is applied. This provides a basis for maintaining precise alignment between the inner tube's protrusion and the outer tube's groove during the insertion process, thus guaranteeing the accurate forming of the final interlocking structure.

[0017] Secondly, regarding continuous and efficient production: the equipment employs a first and second moving extrusion assembly arranged in parallel. These two assemblies are structurally independent but functionally identical. Control logic enables the clamping components of both assemblies to alternately cycle through "clamping-insertion-release-reset," achieving relay-style operation. When the clamping component of the first assembly completes a stroke and resets, the clamping component of the next assembly immediately takes over and continues advancing. This design overcomes the physical limitations of the stroke length of a single drive mechanism, allowing composite tubes of any length to complete continuous and stable insertion within the limited equipment length through multiple relays, greatly improving production efficiency and the ability to process long workpieces.

[0018] Secondly, regarding intelligent space avoidance: the equipment incorporates a posture adjustment mechanism consisting of a hinged base, elastic elements, rollers, and a torsional transmission component. When the clamping component needs to return to its original position, its linear motion is converted into rotation of the hinged base shaft via the rollers and transmission component, driving the clamp and grippers to rotate approximately 90 degrees to a horizontal avoidance posture. This automatic rotation significantly reduces the clamp's profile dimensions in the direction of movement, allowing the clamping components of the two moving extrusion assemblies to move crosswise in a compact spatial layout without collision. When the clamping component reaches the end of its stroke and the rollers stop, the restoring force of the elastic element drives the clamp to automatically rotate back to a vertical working posture. This mechanism cleverly solves the problem of interference between multiple moving parts in a confined space without requiring additional independent drive, ensuring the automation and smoothness of the relay process.

[0019] Finally, regarding the assurance of bonding quality: the entire insertion process is precisely controlled by an electronic control system, ensuring the inner tube's advancement within the outer tube is uniform and smooth. The clamp's anti-slip design protects the tube surface and prefabricated structure, while the relay-style advancement avoids single, violent impacts. This controlled and stable process ensures protection for the precise protrusions, grooves, and missing grooves on the inner and outer tube walls, preventing interlocking failure due to processing damage. This guarantees a complete bonding interface, reliable interlocking effect, and high overall bonding quality in the final composite pipe product. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Wherein: Figure 1 This is a schematic diagram of the bimetallic composite pipe connection in this application; Figure 2 This is a schematic diagram of the bimetallic composite tube synchronous extrusion molding machine of this application; Figure 3 This is a top view schematic diagram of the bimetallic composite tube synchronous extrusion molding machine of this application; Figure 4This is a schematic diagram of the clamping component in this application; Figure 5 This is a cross-sectional schematic diagram of the clamping component of this application.

[0021] In the picture: 1. Outer tube; 11. Groove; 2. Inner tube; 21. Protrusion; 3. Slot; 31. First notch; 32. Second notch; 4. Insert block; 5. Base plate; 51. First moving extrusion assembly; 52. Second moving extrusion assembly; 6. First drive unit; 61. First motor; 62. First double-ended lead screw; 63. Screw seat; 64. Fixing plate; 7. Guide unit; 71. Guide rail; 72. Guide seat; 8. Clamping component; 81. Hinge seat; 811. Support ring; 812. Rotating ring; 813. Rotating shaft; 814. Elastic component; 82. Fixture; 821. Fixed arm; 822. Second double-ended lead screw; 823. Clamping seat; 824. Gripper; 825. Second motor; 83. Attitude adjustment mechanism; 831. Roller; 832. Transmission component. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0023] The terminology used in this invention is that which is currently widely used in the art in consideration of the function of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new technology in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terms used in this specification should not be construed as simple names, but rather based on their meanings and the overall description of the invention.

[0024] Reference Figure 1 This embodiment provides a bimetallic composite tube, including an outer tube 1 and an inner tube 2; the outer wall of the inner tube 2 is provided with a plurality of axially extending protrusions 21 at equal intervals in a ring; the inner wall of the outer tube 1 is provided with grooves 11 that match the shape, number and distribution of the protrusions 21; the protrusions 21 can fit into the grooves 11. The cross-sections of the protrusions 21 and the grooves 11 are trapezoidal.

[0025] The outer tube 1 has multiple first notches 31 spaced apart along its axial direction on its wall; the inner tube 2 has multiple second notches 32 spaced apart along its axial direction on its wall; when the protrusion 21 fits into the groove 11 and the inner tube 2 and the outer tube 1 reach the predetermined insertion position, the corresponding first notches 31 and second notches 32 overlap radially to form a groove 3; a plug 4 is disposed in the groove 3. The cross-sections of the first notches 31, the second notches 32 and the plug 4 are also trapezoidal.

[0026] In this embodiment, the inner tube 2 is made of a specific metal material, and its outer wall is processed to form a series of protrusions 21 that are equidistantly arranged along the circumference of the tube and extend along the axial direction of the tube. These protrusions 21 are regularly distributed on the surface of the inner tube 2 to form an axial reinforcing rib or guide strip. Correspondingly, the outer tube 1 is made of another metal material, and its inner wall is pre-fabricated with grooves 11 that are completely corresponding to the protrusions 21 of the inner tube 2 in terms of number, position and geometric contour through matching processing. The distribution pattern of these grooves 11 is consistent with that of the protrusions 21, so that the inner tube 2 can be accurately inserted into the outer tube 1.

[0027] During assembly, the protrusion 21 of the inner tube 2 is precisely aligned and inserted into the corresponding groove 11 of the outer tube 1. This interlocking design of the protrusion 21 and groove 11 essentially establishes a circumferential mechanical interlock between the two tube layers. After the protrusion 21 is inserted into the groove 11, it effectively prevents relative circumferential rotation between the inner tube 2 and the outer tube 1, fundamentally solving the inherent problem of slippage and rotation in traditional smooth-surface composite tubes, and significantly improving the torsional resistance and joint stability of the composite tube. Preferably, the cross-sections of the protrusion 21 and the groove 11 can be designed as trapezoids. This shape can play a good guiding role during the insertion process and produce a wedge-tightening effect after final joining, further enhancing the firmness of the connection.

[0028] In addition to the aforementioned protrusions 21 and grooves 11 for preventing rotation, the composite tube can also have an axial locking mechanism to further prevent axial movement. Specifically, multiple annularly distributed first notches 31 and second notches 32 can be machined at corresponding positions along the axial direction on the already inserted outer tube 1 and inner tube 2. When the inner and outer tubes 1 are inserted to a predetermined depth, these notches are aligned radially to form a complete groove 3. At this time, a matching insert block 4 (e.g., a metal block with a trapezoidal cross-section) is inserted into the groove 3, which can achieve absolute axial locking between the inner tube 2 and the outer tube 1, effectively preventing relative axial displacement when subjected to force. This notched structure can also serve as a positioning reference for the subsequent specialized extrusion molding equipment to accurately clamp the tube during the manufacturing process, achieving a clever unity between structural function and manufacturing process.

[0029] Reference Figures 2-5This embodiment provides a bimetallic composite tube synchronous extrusion molding machine for producing bimetallic composite tubes, which includes a base plate 5 and a first moving extrusion assembly 51 and a second moving extrusion assembly 52 arranged side by side on the base plate 5; the first moving extrusion assembly 51 and the second moving extrusion assembly 52 each include a first driving unit 6, a guiding unit 7 and two clamping members 8; the first driving unit 6 is used to drive the two clamping members 8 to move towards or away from each other along the guiding unit 7; each clamping member 8 is provided with a clamp 82 for clamping the tube.

[0030] This bimetallic composite tube synchronous extrusion molding machine adopts a dual-station system that can work alternately to achieve continuous, stable, and precise insertion of long-length composite tubes. It uses a base plate 5 as the mounting foundation, on which two sets of identical and independently controlled moving extrusion assemblies are arranged in parallel, defined as the first moving extrusion assembly 51 and the second moving extrusion assembly 52, respectively. Each set of moving extrusion assemblies constitutes a complete insertion station, which includes three main functional parts: power drive, motion guidance, and workpiece clamping.

[0031] Specifically, each moving extrusion assembly is equipped with a first drive unit 6, which serves as a power source. Its output motion is designed to synchronously drive the two clamping members 8 to perform linear movements in opposite directions (closing) or opposite directions (separating). To ensure smooth and precise movement, the moving extrusion assembly also includes a guide unit 7 parallel to the first drive unit 6. This guide unit 7 works in conjunction with the first drive unit 6 to provide rigid constraints and guidance for the movement of the clamping members 8, preventing them from swaying or jamming during movement. The two clamping members 8 in each moving extrusion assembly are the functional terminals that directly execute the operation. They are mounted on a motion platform composed of the first drive unit 6 and the guide unit 7. Each clamping member 8 integrates a dedicated clamp 82, which has an active opening and closing function, capable of firmly clamping or releasing the workpiece, i.e., the outer tube 1 or the inner tube 2, according to instructions. Under the control of the first drive unit 6, the two clamping members 8 can respectively clamp the outer tube 1 and the inner tube 2 to be mated, and then move towards each other precisely and at a constant speed, so as to smoothly push the inner tube 2 into the outer tube 1 and complete the insertion operation of a predetermined length.

[0032] This design utilizes an alternating relay working mode of two sets of moving extrusion components. After the first moving extrusion component 51 completes a section of the insertion stroke, its clamping member 8 can release the tube and reset. Simultaneously, the second moving extrusion component 52 can immediately take over, clamping the partially inserted tube and continuing to advance. This design overcomes the bottleneck of limited stroke in a single unit, making continuous insertion of ultra-long composite tubes possible, greatly improving production efficiency and process continuity. The parallel layout of the two components provides the spatial basis for this seamless relay, while their independent and coordinated control systems ensure the continuity and high precision of the entire insertion process.

[0033] The first drive unit 6 includes a first double-ended lead screw 62 and a first motor 61 that drives the first double-ended lead screw 62 to rotate; the guide unit 7 includes a guide rail 71 that is parallel to the first double-ended lead screw 62; the clamping member 8 includes a guide seat 72 that slides with the guide rail 71, a screw seat 63 that is threaded with the first double-ended lead screw 62, and a fixing plate 64 that connects the guide seat 72 and the screw seat 63.

[0034] The first drive unit 6 includes a first double-ended lead screw 62 and a first motor 61 that drives the lead screw to rotate. The first double-ended lead screw 62 is designed with threaded sections at both ends with opposite directions of rotation, so that it can drive the two parts that cooperate with it to make synchronous linear movements in opposite directions when rotating. The first motor 61, as a power source, is usually a servo motor or a stepper motor. Its output shaft is directly connected to one end of the first double-ended lead screw 62 or through a coupling. It can receive control signals and output precise angles and speeds, thereby controlling the moving speed and position of the clamping part 8. To constrain the motion trajectory and ensure rigidity, a guide rail 71 is arranged parallel to the first double-ended lead screw 62 as a guide unit 7. The guide rail 71 is usually a high-precision linear guide rail 71, fixed on the equipment base plate 5, providing low-friction, high-rigidity linear guidance for the moving parts.

[0035] The clamping component 8, as the moving part that directly supports the clamp 82, is structurally designed to ensure the coordination of drive and guidance. It includes a guide seat 72 that slides with the guide rail 71, suspending and constraining the clamping component 8 onto the guide rail 71 to ensure smooth sliding along a predetermined straight path, primarily bearing radial force and overturning moment. Simultaneously, the clamping component 8 also includes a screw seat 63 that engages with the corresponding threaded section on the first double-ended lead screw 62, converting the rotational motion of the first motor 61 into its own linear motion and providing the main propulsion force. To integrate the functions of the guide seat 72 and the screw seat 63 into a stable mounting platform, they are connected by a rigid fixing plate 64. This fixing plate 64 not only achieves a mechanical fixed connection between the guide seat 72 and the screw seat 63, allowing them to move as a single unit, but more importantly, its upper space is used for mounting the subsequent hinge seat 81 and clamp 82. This design, which uses a lead screw to provide thrust, a guide rail 71 to guide and constrain the path, and a fixed plate 64 to integrate the load-bearing capacity, ensures that each clamping component 8 can move smoothly, synchronously, and with high precision under the precise control of the first motor 61. This is the foundation for realizing the subsequent relay-type precision insertion process.

[0036] The clamp 82 includes a fixed arm 821, a second double-ended lead screw 822 mounted on the fixed arm 821, a second motor 825 that drives the second double-ended lead screw 822 to rotate, and two clamping seats 823 that respectively engage with the two threaded sections of the second double-ended lead screw 822; each clamping seat 823 is provided with a clamping jaw 824. The thickness of the clamping jaw 824 is configured to match the shape of the groove 3 on the outer wall of the tube to be clamped.

[0037] The clamp 82 uses a fixed arm 821 as its main support structure. This fixed arm 821 is shaped like a "7," and the upper end of the second double-ended lead screw 822 is mounted on it via bearings. Similar to the lead screw principle in the first drive unit 6, the two ends of the second double-ended lead screw 822 also have threaded sections with opposite directions of rotation. The power to drive its rotation comes from a second motor 825 fixed to the fixed arm 821. Two clamps 823 are fitted onto the second double-ended lead screw 822, each engaging with a threaded section with a different direction of rotation. When the second motor 825 starts and drives the second double-ended lead screw 822 to rotate, due to the opposite directions of rotation of the threads, the two clamps 823 will precisely perform synchronous, opposite-direction linear movements under the drive of the second double-ended lead screw 822. This design is the core of enabling the clamp 82 to open and close actively and precisely.

[0038] Each clamp 823 has a gripper 824 mounted on its front end. These two grippers 824 move synchronously with the clamp 823 to form a clamp 82. Its unique feature is that the grippers 824 are relatively thin, allowing them to engage with pre-machined grooves 3 (i.e., the combination of the first notch 31 and the second notch 32) on the outer wall of the tube to be clamped (outer tube 1 or inner tube 2). When the clamp 823 closes under the drive of the second motor 825, the two grippers 824 can embed into the corresponding grooves 3 on the tube, forming a "click" type mechanical interlock, rather than relying solely on friction for clamping. This design ensures that during subsequent high-thrust insertion operations, there will be no relative slippage or rotation between the tube and the clamp 82, providing a fundamental guarantee for achieving millimeter-level insertion alignment accuracy, while also avoiding damage to the tube surface caused by slippage.

[0039] A hinge seat 81 is provided on the fixed plate 64, and the clamp 82 is mounted on the fixed plate 64 through the hinge seat 81. The hinge seat 81 includes a support ring 811 connected to the fixed plate 64, a rotating ring 812 connected to the clamp 82, and a rotating shaft 813 connecting the support ring 811 and the rotating ring 812. An elastic element 814 is provided on the rotating shaft 813 to give it a return tendency. It also includes an attitude adjustment mechanism 83. The attitude adjustment mechanism 83 includes a roller 831 disposed between the guide seat 72 and the screw seat 63, and a transmission element 832 connecting the roller 831 and the rotating shaft 813.

[0040] The clamp 82 is not directly and rigidly fixed to the fixed plate 64 of the clamping member 8, but is connected to it through a hinge seat 81. The hinge seat 81 is the hub for realizing the rotational movement of the clamp 82. It mainly consists of three parts: a support ring 811 that is firmly connected to the fixed plate 64, a rotating ring 812 that is firmly connected to the fixed arm 821 of the clamp 82, and a rotating shaft 813 that passes through and connects the support ring 811 and the rotating ring 812. In order to give the clamp 82 a stable default working posture, an elastic element 814 (such as a torsion spring) is installed on the rotating shaft 813. The elastic element 814 is pre-tightened, and its natural tendency is to drive the rotating ring 812 together with the entire clamp 82 to maintain in a preset position, usually in a vertical state, so as to ensure that the clamp 82 can properly align and clamp the horizontally placed pipe.

[0041] To enable the clamp 82 to automatically perform attitude changes during equipment operation, an attitude adjustment mechanism 83 is also integrated. The attitude adjustment mechanism 83 is linked to the linear motion of the clamping member 8. Its components include a roller 831 disposed between the guide seat 72 and the screw seat 63, and a transmission member 832 connecting the roller 831 and the pivot 813 of the aforementioned hinge seat 81. The transmission member 832 is a belt that is specially twisted into a specific shape (such as an "8") to adapt to the perpendicular angle between the roller 831 and the pivot 813.

[0042] Its working logic is as follows: When the clamping member 8 carries the clamp 82 in a linear movement (especially during the return stroke), the roller 831 rolls on the base plate 5. The rotational motion of the roller 831 is transmitted to the rotating shaft 813 of the hinge seat 81 through the twisted transmission member 832, which is converted into the rotational torque of the rotating shaft 813. This torque overcomes the reset force of the aforementioned elastic member 814 and drives the rotating shaft 813 to rotate, thereby causing the entire clamp 82 to rotate about 90 degrees around the axis, changing from a vertical working posture to a horizontal avoidance posture. This rotational action minimizes the profile of the clamp 82 and its grippers 824 during the return process, allowing it to pass through the narrow space between another set of clamping members 8 performing the insertion task in the central area without collision. When the clamp 82 rotates to the position, it is mechanically limited by the fixed plate 64 after rotating to a horizontal state and cannot continue to rotate. Consequently, the transmission member 832 begins to slip, allowing the clamping member 8 to continue moving to the end point while the clamp 82 maintains a horizontal avoidance posture. Upon reaching the endpoint, roller 831 stops, and the restoring force of elastic element 814 drives shaft 813 to rotate in the opposite direction, automatically and reliably restoring clamp 82 to a vertical ready state, ready for the next clamping operation. When clamping element 8 carries clamp 82 in a linear movement (especially during the outward movement of merging), roller 831 drives transmission element 832 to bring clamp 82 to a vertical position, consistent with the torsion spring bringing clamp 82 to a vertical position. This design achieves complete automation and synchronization of posture changes without the need for an additional independent drive unit, ensuring the efficiency and smoothness of the relay insertion process.

[0043] Reference Figures 2-5 A method for simultaneous extrusion molding using the above-mentioned equipment. The steps of this method are as follows: Step S1: Initial Preparation and First-Stage Insertion. The two clamping members 8 of the first moving extrusion assembly 51 are at their outermost ends of travel (separated state). The operator places the outer tube 1 into the clamp 82 of one of the clamping members 8, and places the inner tube 2 (ensuring its protrusion 21 aligns with the groove 11 of the outer tube 1) into the clamp 82 of the other clamping member 8. The second motor 825 of the two clamping members 82 is activated to drive the clamping seats 823 to close, so that the jaws 824 precisely engage with the first notch 31 of the outer tube 1 and the second notch 32 of the inner tube 2, completing a secure clamping. The first motor 61 of the first moving extrusion assembly 51 is activated, and the first double-ended lead screw 62 rotates, driving the two screw seats 63 to move their respective clamping members 8 along the guide rail 71 towards the center (closing motion). During this process, the inner tube 2, guided by the outer tube 1, smoothly slides its protrusion 21 along the groove 11, achieving precise insertion in the first stage. When the two clamping members 8 move to the center position and approach each other, the first-stage insertion is complete.

[0044] Step S2: Relay transition and posture avoidance.

[0045] Second moving extrusion assembly 52 preparation: At the same time or slightly earlier as the initial preparation in step S1 and the first segment insertion, the two clamping parts 8 of the second moving extrusion assembly 52 have clamped the new outer tube 1 and inner tube 2 at both ends respectively (or as a backup for relay).

[0046] First component release and reset: After the first segment is inserted, the two clamps 82 of the first moving extrusion component 51 release their grip on the pipe.

[0047] Posture Rotation Avoidance: The first motor 61 of the first moving extrusion assembly 51 reverses, driving the two clamping members 8 to separate and reset at both ends. At the initial moment of movement, the roller 831 rolls in the opposite direction with the guide seat 72 and the screw seat 63, transmitting the rotational motion to the pivot 813 of the hinge seat 81 through the figure-eight belt. Overcoming the resistance of the torsion spring, the entire clamp 82 and jaws 824 rotate rapidly by about 90 degrees, changing from a vertical to a horizontal state. In this state, the profile of the clamp 82 is minimized, and it will not interfere with the clamping members 8 of the second moving extrusion assembly 52 that are working in the central area. After the clamp 82 rotates to its position, the belt begins to slip, and the clamping members 8 continue to move outward in a horizontal posture.

[0048] Step S3: Relay insertion and loop.

[0049] The first motor 61 of the second moving extrusion assembly 52 starts, repeating the initial preparation and closing motion of the first segment insertion in step S1. Its two clamping parts 8 clamp the tube and move it towards the center, continuing to push the inner tube 2 deeper into the outer tube 1 for the second segment insertion relay. At the same time, the clamping parts 8 of the first moving extrusion assembly 51 have moved to the outermost end. At this time, the roller 831 stops, and the torsion spring drives the rotating shaft 813 to rotate, so that the clamp 82 automatically returns to the vertical ready state. When the clamping parts 8 of the second moving extrusion assembly 52 move to the center and complete the second segment insertion, the first moving extrusion assembly 51 is ready to clamp and relay again. In this way, the two sets of moving extrusion assemblies alternately perform the cycle of "clamping, insertion, release, and reset", like a "relay race", until the inner tube 2 is completely inserted into the outer tube 1, and all the corresponding first notches 31 and second notches 32 are completely coincident in the axial direction.

[0050] Step S4: Final locking.

[0051] After the insertion is completed, the trapezoidal cross-section insert 4 is hammered or pressed into the annular groove 3 formed by the overlapping first notch 31 and second notch 32 one by one, so as to achieve the final axial mechanical locking of the inner tube 2 and the outer tube 1, and obtain a bimetallic composite tube finished product with a firm connection and no risk of relative displacement.

[0052] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A bimetallic composite pipe, characterized by: The outer tube (1) and the inner tube (2) are provided; the outer wall of the inner tube (2) is provided with a plurality of axially extending protrusions (21) at equal intervals; the inner wall of the outer tube (1) is provided with grooves (11) matching the shape, number and distribution of the protrusions (21); the protrusions (21) can be embedded in the grooves (11).

2. The bi-metallic composite pipe according to claim 1, characterized in that: A plurality of first missing grooves (31) are arranged on the wall of the outer tube (1) at intervals along the axial direction; a plurality of second missing grooves (32) are arranged on the wall of the inner tube (2) at intervals along the axial direction; When the protrusions (21) are embedded in the grooves (11) and the inner tube (2) reaches the predetermined plug-in position of the outer tube (1), the corresponding first missing grooves (31) and the second missing grooves (32) coincide in the radial direction to form an embedded groove (3); the embedded groove (3) is provided with an insertion block (4).

3. A bimetallic composite pipe simultaneous extrusion forming machine characterized by: A method for manufacturing the bimetal composite pipe according to claim 1 or 2 comprises a base plate (5), and a first moving extrusion assembly (51) and a second moving extrusion assembly (52) arranged side by side on the base plate (5); The first moving extrusion assembly (51) and the second moving extrusion assembly (52) each comprise a first driving unit (6), a guide unit (7) and two clamping members (8); The first driving unit (6) is used to drive the two clamping members (8) to move towards or away from each other along the guide unit (7); each clamping member (8) is provided with a clamp (82) for clamping the pipe.

4. The bimetallic composite pipe simultaneous extrusion forming machine according to claim 3, characterized in that: The first driving unit (6) comprises a first double-headed screw (62) and a first motor (61) for driving the first double-headed screw (62) to rotate; the guide unit (7) comprises a guide rail (71) arranged parallel to the first double-headed screw (62); The clamping member (8) comprises a guide seat (72) slidingly matched with the guide rail (71), a screw seat (63) threadedly matched with the first double-headed screw (62), and a fixed plate (64) connecting the guide seat (72) and the screw seat (63).

5. The bimetallic composite pipe simultaneous extrusion forming machine according to claim 3, characterized in that: The clamp (82) comprises a fixed arm (821), a second double-headed screw (822) arranged on the fixed arm (821), a second motor (825) for driving the second double-headed screw (822) to rotate, and two clamping seats (823) threadedly matched with two segments of the second double-headed screw (822) respectively; each clamping seat (823) is provided with a clamping jaw (824).

6. The bimetallic composite pipe simultaneous extrusion forming machine according to claim 4, characterized in that: The fixed plate (64) is provided with a hinged seat (81), and the clamp (82) is installed on the fixed plate (64) through the hinged seat (81); the hinged seat (81) comprises a support ring (811) connected with the fixed plate (64), a rotating ring (812) connected with the clamp (82), and a rotating shaft (813) connecting the support ring (811) and the rotating ring (812); the rotating shaft (813) is provided with an elastic member (814) having a restoring tendency.

7. The bimetallic composite pipe simultaneous extrusion forming machine according to claim 6, characterized in that: Further comprising a posture adjusting mechanism (83); the posture adjusting mechanism (83) comprises a roller (831) arranged between the guide base (72) and the screw base (63), and a transmission member (832) connecting the roller (831) and the rotating shaft (813).

8. The bimetallic composite pipe simultaneous extrusion forming machine according to claim 5, characterized in that: The thickness of the clamping jaw (824) is configured to be matched with the shape of the embedded groove (3) on the outer wall of the pipe to be clamped.

9. The bimetallic composite pipe simultaneous extrusion forming machine according to claim 2, characterized in that: The cross section of the protrusion (21) and the recess (11) is trapezoidal; the cross section of the first missing groove (31), the second missing groove (32) and the insertion block (4) is also trapezoidal.

10. The bimetallic pipe simultaneous extrusion forming machine according to any one of claims 7-9, characterized in that: The method comprises the following steps: The two clamping members (8) of the first moving extrusion assembly (51) clamp the outer pipe (1) and the inner pipe (2) respectively, and move towards each other under the driving of the first driving unit (6), so that a part of the length of the inner pipe (2) is inserted into the outer pipe (1), and the first section of insertion is completed; Then, the clamping members (8) of the first moving extrusion assembly (51) release the pipes and reset, and in the resetting process, the clamp (82) rotates to the avoiding posture under the action of the posture adjusting mechanism (83); The two clamping members (8) of the second moving extrusion assembly (52) clamp the outer pipe (1) and the inner pipe (2) which have completed the first section of insertion respectively, and drive them to continue moving towards each other, so that the second section of insertion is completed; The above steps are alternately repeated until the inner pipe (2) and the outer pipe (1) are completely inserted in place; The insertion block (4) is inserted into the embedded groove (3) formed by the coinciding first missing groove (31) and second missing groove (32).

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