An eccentric upset process

Abstract

The present application belongs to the technical field of mechanical assembly, and relates to an eccentric expanding process, which utilizes an eccentric expanding device, the eccentric expanding device comprising a rotary driving device and an eccentric die, one end of the eccentric die being connected with the rotary driving device, and the other end of the eccentric die being provided with an eccentric protrusion, and comprising the following steps: S1, inserting a metal pipe into a pipe hole of a flange to form a to-be-expanded assembly; S2, fixing the to-be-expanded assembly; S3, adjusting the position of the eccentric die so that the axis of the eccentric die coincides with the axis of the metal pipe, and inserting one end of the eccentric die with the eccentric protrusion into the metal pipe; S4, moving the eccentric die by a distance d along the radial direction of the metal pipe so that the eccentric protrusion contacts the inner wall of the metal pipe; S5, starting the rotary driving device to drive the eccentric die to rotate, and extruding the inner wall of the metal pipe through the eccentric protrusion to make the metal pipe plastically deform, thereby realizing the connection between the metal pipe and the flange; and S6, withdrawing the eccentric die. The present application can replace the existing expanding process and avoid secondary processing of the clamping groove.

Description

Technical Field

[0001] This invention relates to an eccentric expansion joint process, belonging to the field of mechanical assembly technology. Background Technology

[0002] In the automotive design and manufacturing field, a metal tube flange assembly is a component that connects a metal tube to a flange. Common structural forms include a single-tube connection with a single flange and a double-tube connection with a single flange. In a single-tube structure, a pipe hole is opened on the flange, and the metal tube is directly inserted into this hole. In a double-tube structure, [reference...] Figure 10 As shown, two pipe holes are symmetrically opened on the flange 602, and two independent metal pipes 601 are inserted into the corresponding pipe holes respectively. Typically, the ends of the metal pipes 601 are machined with internal threads 604 for connection with other components, and an annular groove 603 is provided on the outside for cooperation with the clamping plate to achieve pipe positioning on the frame.

[0003] For single-pipe flange assemblies, the industry commonly uses a single-pipe tightening connection process. This involves initially leaving the annular groove on the outside of the metal pipe unprocessed during assembly, then directly fitting the flange into place using an interference fit. The annular groove is then machined onto the metal pipe. However, this tightening process cannot currently be directly applied to double-pipe flange assemblies because existing equipment and technology cannot simultaneously machine the annular grooves on the outside of two closely adjacent metal pipes in an assembled double-pipe flange assembly.

[0004] Therefore, for double-pipe metal flange assemblies, welding is currently the primary method for achieving a fixed connection between the metal pipe and the flange. While welding meets structural requirements, it significantly increases manufacturing costs. This is because welding requires specialized welding equipment, highly skilled operators, and consumes auxiliary consumables such as welding wire and shielding gas. These equipment, labor, and material costs directly drive up the production cost of a single double-pipe flange assembly. Summary of the Invention

[0005] The purpose of this invention is to provide a new technical solution to improve or solve the technical problems existing in the prior art as described above.

[0006] The technical solution provided by this invention is as follows: An eccentric expansion joint process, utilizing an eccentric expansion joint device, the eccentric expansion joint device comprising a rotary drive device and an eccentric mold, one end of the eccentric mold being connected to the rotary drive device, and the other end of the eccentric mold being eccentrically provided with an eccentric protrusion, comprising the following steps:

[0007] S1. Insert the metal pipe into the pipe hole of the flange to form the assembly to be expanded;

[0008] S2. Fix the component to be expanded;

[0009] S3. Adjust the position of the eccentric mold so that its axis coincides with the axis of the metal tube, and insert the end of the eccentric mold with the eccentric protrusion into the metal tube.

[0010] S4. Move the eccentric mold a distance d along the radial direction of the metal tube so that the eccentric protrusion contacts the inner wall of the metal tube.

[0011] S5. Start the rotary drive device to drive the eccentric mold to rotate, and use the eccentric protrusion to squeeze the inner wall of the metal tube to cause plastic deformation, thereby connecting the metal tube to the flange.

[0012] S6, Exit the eccentric model.

[0013] Compared with the prior art, the technical solution provided by this invention has the following advantages: This invention controls the contact interference between the eccentric protrusion and the inner wall of the metal tube by radially moving the eccentric mold by a specific distance d. During the rotation process, the eccentric protrusion applies continuous circumferential extrusion to the inner wall of the metal tube, causing local plastic deformation in the contact area, forcing the metal tube material to tightly adhere to the inner wall of the flange tube hole, forming a mechanical interlock, reducing manufacturing costs. For single-tube structures, it can replace the existing tensioning process and avoid secondary machining of the slot. For double-tube structures, it can completely solve the problem of tool interference caused by the small tube spacing, and achieve reliable connection without welding.

[0014] Based on the above technical solution, the present invention can be further improved as follows.

[0015] Furthermore, in step S1, before the metal pipe is inserted into the flange, an internal thread hole and a groove are machined at the end of the metal pipe.

[0016] The beneficial effects of adopting the above-mentioned further solutions are:

[0017] Further, in step S2, the component to be expanded is fixed by a positioning fixture, which includes a pipe end support, a positioning block and a pipe tail support. The positioning block is installed on the pipe end support, and the positioning block is provided with a front positioning groove, and the pipe tail support is provided with a rear positioning groove.

[0018] The beneficial effect of adopting the above-mentioned further solution is that the positioning fixture, through the cooperation of the pipe end support, positioning block, and pipe tail support, achieves stable fixation of the metal pipe flange assembly. The positioning grooves on the positioning block and pipe tail support can hold the metal pipe flange assembly to be expanded, preventing movement or displacement during the expansion process, thereby ensuring the accuracy and quality of the expansion. In addition, this positioning fixture has a simple structure, is easy to operate, and greatly improves work efficiency.

[0019] Furthermore, in step S2, the positioning fixture also includes a pin and a spring. Axial positioning is achieved by inserting the pin into the opening of the metal pipe, and the pin is kept in the inserted state under the action of the spring.

[0020] The beneficial effect of adopting the above-mentioned further solution is that, before expansion, the pin is inserted into the end of the metal pipe and pressed and positioned under the action of the spring, which enhances the stability of the metal pipe and prevents displacement or deformation caused by uneven force during the expansion process. After expansion is completed, the pin can be easily pulled out, facilitating the removal of the expanded metal pipe flange assembly, thus improving the convenience and efficiency of operation.

[0021] Furthermore, in step S2, the positioning fixture also includes a pressing block and a cylinder. The pressing block is connected to the output shaft of the cylinder, and the pressing block is driven by the cylinder to press the flange.

[0022] The beneficial effect of adopting the above-mentioned further solution is that, during the expansion process, the pressing block applies a stable clamping force to the flange under the drive of the cylinder, ensuring the stability of the flange position during the expansion process and preventing poor expansion caused by flange movement.

[0023] Furthermore, in steps S3 and S4, the lateral insertion and longitudinal movement of the eccentric mold are achieved by a moving device, which includes a first base plate, a second base plate, a first drive cylinder, and a second drive cylinder; the first drive cylinder drives the first base plate to move laterally; the second drive cylinder drives the second base plate to move longitudinally; and a rotation drive device is mounted on the second base plate.

[0024] The beneficial effect of adopting the above-mentioned further solution is that, through the cooperation of the first drive cylinder and the second drive cylinder, the positioning of the rotary drive device in the two-dimensional worktable is realized, thereby ensuring that the eccentric mold can accurately align with and contact the inner wall of the metal tube to be expanded, so that it can meet the expansion requirements of different positions and angles.

[0025] Furthermore, the workbench is provided with a first slide rail, the first base plate is slidably mounted on the first slide rail, and a second slide rail is provided above the first base plate, the second base plate is slidably mounted on the second slide rail.

[0026] The beneficial effect of adopting the above-mentioned further solution is that by setting the first slide rail and the second slide rail, a stable guide is provided for the sliding of the first base plate and the second base plate, which further improves the positioning accuracy and stability of the moving device and ensures the accuracy and reliability of the expansion process.

[0027] Furthermore, a support seat is also provided on the second base plate. The support seat is located between the rotary drive device and the positioning fixture. In step S5, the eccentric mold is rotated and supported by the bearing in the support seat.

[0028] The beneficial effects of adopting the above-mentioned further solution are that the support base design effectively supports and fixes the eccentric mold, keeping it stable during rotation and avoiding vibration and deviation caused by rotation, thus further improving the expansion accuracy and efficiency. At the same time, the use of bearings makes the rotation of the eccentric mold smoother, reducing friction and wear, and extending the service life of the equipment.

[0029] Furthermore, the first drive cylinder is a pneumatic cylinder, the second drive cylinder is a servo motor, and the rotary drive device is a geared motor.

[0030] The advantages of adopting the above-mentioned further solutions are that the cylinder has the advantages of simple structure, reliable operation, easy maintenance and low cost, and is suitable for driving the first base plate to move quickly laterally; the servo motor has precise control, smooth operation and can achieve high-precision positioning, and is suitable for driving the second base plate to move longitudinally to ensure that the eccentric mold can accurately reach the expansion position; the geared motor can provide stable rotational driving force and the speed is adjustable, and is suitable for driving the eccentric mold to rotate and expand. This combination ensures the stability and accuracy of the expansion process, and also takes into account the economy and practicality of the equipment.

[0031] Furthermore, in step S4, the distance d ranges from 0.1mm to 0.3mm.

[0032] The beneficial effect of adopting the above-mentioned further solution is that by precisely controlling the moving distance d of the eccentric mold, the amount of plastic deformation of the inner wall of the metal pipe during the expansion process is ensured to be moderate. This not only achieves a firm connection between the metal pipe and the flange, but also avoids problems such as metal pipe rupture or flange damage caused by excessive deformation, thereby greatly improving the expansion quality and product reliability. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0034] Figure 1 This is a three-dimensional structural diagram of the eccentric expansion joint device of the present invention;

[0035] Figure 2 This is a three-dimensional structural schematic diagram of the eccentric expansion joint device of the present invention from another perspective;

[0036] Figure 3 This is a front view of the eccentric expansion joint device of the present invention;

[0037] Figure 4 This is a top view of the eccentric expansion joint device of the present invention;

[0038] Figure 5 The eccentric expansion joint device of the present invention Figure 4 Enlarged view of part A;

[0039] Figure 6 This is a three-dimensional structural diagram of the eccentric mold of the eccentric expansion joint device of the present invention;

[0040] Figure 7 This is a three-dimensional structural diagram of the positioning fixture for the eccentric expansion joint device of the present invention;

[0041] Figure 8 This is a front view of the positioning fixture for the eccentric expansion joint device of the present invention;

[0042] Figure 9 This is a side view of the positioning fixture for the eccentric expansion joint device of the present invention;

[0043] Figure 10 This is a perspective view of the metal pipe flange assembly of the eccentric expansion joint device of the present invention;

[0044] Figure 11 This is a schematic diagram of the structure of the metal pipe flange assembly of the eccentric expansion joint device of the present invention installed on the eccentric expansion joint device;

[0045] Figure 12 This is a schematic diagram of the eccentric mold extending into the metal tube according to the present invention;

[0046] Figure 13 This is a schematic diagram of the structure of the present invention, showing the eccentric mold extending into the metal tube and offset along the longitudinal direction by a distance d.

[0047] In the diagram, 100 is the workbench; 200 is the moving device; 201 is the first base plate; 202 is the second base plate; 203 is the first drive cylinder; 204 is the second drive cylinder; 300 is the rotary drive device; 301 is the support base; 302 is the bearing; 400 is the eccentric mold; 401 is the eccentric protrusion; 500 is the positioning fixture; 501 is the pipe end support; 502 is the positioning block; 503 is the pipe tail support; 5041 is the front positioning groove; 5042 is the rear positioning groove; 505 is the pin; 506 is the spring; 507 is the limit block; 508 is the pressing block; 509 is the cylinder; 600 is the metal pipe flange assembly; 601 is the metal pipe; 602 is the flange; 603 is the annular groove; and 604 is the internal thread. Detailed Implementation

[0048] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the objects described and do not imply any priority in order or any specific technical meaning. Furthermore, the concepts of "connection" and "linkage" mentioned in this application, unless otherwise specified, are considered to include both direct connection (linkage) and indirect connection (linkage).

[0049] When interpreting the description of this application, it should be clarified that terms such as "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating directions or positional relationships, are based on the perspective and layout shown in the accompanying drawings. They are intended to facilitate explanation and simplify the description process, and are not absolute limitations on the actual location, construction method, or operating mode of the described device or element. Therefore, these terms should not be construed as restrictive interpretations of the content of this application.

[0050] The principles and features of the present invention are described below with reference to examples. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0051] like Figure 1 - Figure 9 As shown, an eccentric expansion joint process utilizes an eccentric expansion joint device, which includes a rotary drive device 300 and an eccentric mold 400. One end of the eccentric mold 400 is connected to the rotary drive device 300, and the other end of the eccentric mold 400 is eccentrically provided with an eccentric protrusion 401. The process includes the following steps:

[0052] S1. Insert the metal pipe 601 into the pipe hole of the flange 602 to form the expansion assembly 600;

[0053] S2. Fix the expansion joint component 600;

[0054] S3. Adjust the position of the eccentric mold 400 so that its axis coincides with the axis of the metal tube 601, and insert the end of the eccentric mold 400 with the eccentric protrusion 401 into the metal tube 601.

[0055] S4. Move the eccentric mold 400 a distance d along the radial direction of the metal tube 601 so that the eccentric protrusion 401 contacts the inner wall of the metal tube 601.

[0056] S5. Start the rotary drive device 300 to drive the eccentric mold 400 to rotate, and use the eccentric protrusion 401 to squeeze the inner wall of the metal tube 601 to cause plastic deformation, thereby realizing the connection between the metal tube 601 and the flange 602.

[0057] S6, Exit eccentric module 400.

[0058] In this embodiment, as Figure 6As shown, the eccentric mold 400 is cylindrical, and the eccentric protrusion 401 is semi-circular. The eccentric protrusion 401 is disposed on the outer surface of the eccentric mold 400 near its end. Because the eccentric protrusion 401 is off-center, when the eccentric mold 400 rotates around its central axis, the trajectory of the eccentric protrusion 401 is a circle larger than the trajectory of the outer surface of the eccentric mold 400 itself. During rotation, the eccentric protrusion 401 exerts a compressive force on the inner wall of the metal tube 601, causing plastic deformation of the inner wall of the metal tube 601 in a specific area. This allows the material of the inner wall of the metal tube 601 to flow outwards, filling the gap between the metal tube 601 and the flange 602, thereby achieving a tight connection between the metal tube 601 and the flange 602.

[0059] In this embodiment, more specifically, the eccentric expansion joint device further includes a worktable 100, a moving device 200, and a positioning fixture 500. The moving device 200 is located on the worktable 100, and the moving device 200 can drive the rotary drive device 300 to achieve lateral (refer to) Figure 1 X-axis and longitudinal movement (reference) Figure 1 (Y direction in the middle); the positioning fixture 500 is set on the workbench 100 and is used to fix the metal pipe flange assembly 600 to be expanded; one end of the eccentric mold 400 is connected to the rotating shaft of the rotary drive device 300, and the other end of the eccentric mold 400 is eccentrically provided with an eccentric protrusion 401.

[0060] By controlling the lateral and longitudinal positions of the rotary drive device 300 through the moving device 200, the eccentric mold 400 can be accurately inserted into the metal tube 601 and make good contact with the inner wall. When the eccentric protrusion 401 at the end of the eccentric mold 400 rotates under the drive of the rotary drive device 300, it can exert a continuous and stable squeezing effect on the inner wall of the metal tube 601, causing the inner wall of the metal tube 601 to deform uniformly, thus achieving a firm connection between the metal tube 601 and the flange 602.

[0061] In this embodiment, the moving device 200 includes a first base plate 201, a second base plate 202, a first drive cylinder 203, and a second drive cylinder 204. The first base plate 201 is slidably mounted on the worktable 100. The first drive cylinder 203 is connected to the first base plate 201 and is used to drive the first base plate 201 to move laterally. The second base plate 202 is slidably mounted on the first base plate 201. The second drive cylinder 204 is connected to the second base plate 202 and is used to drive the second base plate 202 to move longitudinally. The rotary drive device 300 is mounted on the second base plate 202. Through the cooperation of the first drive cylinder 203 and the second drive cylinder 204, the rotary drive device 300 is positioned within the two-dimensional worktable 100 plane, thereby ensuring that the eccentric mold 400 can accurately align with and contact the inner wall of the metal tube 601 to be expanded, so that it can meet the expansion requirements of different positions and angles.

[0062] The workbench 100 is provided with a first slide rail, and the first base plate 201 is slidably mounted on the first slide rail. A second slide rail is provided above the first base plate 201, and the second base plate 202 is slidably mounted on the second slide rail. By setting the first and second slide rails, a stable guide is provided for the sliding of the first base plate 201 and the second base plate 202, further improving the positioning accuracy and stability of the moving device 200 and ensuring the accuracy and reliability of the expansion process.

[0063] The eccentric expansion joint device also includes a support base 301, which is disposed on the second base plate 202. The support base 301 is located between the rotary drive device 300 and the positioning fixture 500. Both ends of the eccentric mold 400 pass through the support base 301 and are rotatably mounted on the support base 301 via bearings 302. The design of the support base 301 effectively supports and fixes the eccentric mold 400, ensuring its stability during rotation and preventing vibration and deviation caused by rotation. Simultaneously, the use of bearings 302 makes the rotation of the eccentric mold 400 smoother, reducing friction and wear, and extending the service life of the equipment.

[0064] The positioning fixture 500 is mainly used to stably fix the metal pipe flange assembly 600 in the eccentric expansion equipment to ensure the smooth expansion process. The positioning fixture 500 includes a pipe end support 501, a positioning block 502, a pipe tail support 503, a pin 505, a spring 506, and a pressing positioning assembly. The positioning block 502 is mounted on the pipe end support 501 and has a front positioning groove 5041. The pipe tail support 503 also has a rear positioning groove 5042. The pin 505 passes through the pipe tail support 503, and the spring 506 is sleeved on the pin 505. The end of the pin 505 has a limiting block 507. One end of the spring 506 abuts against the limiting block 507, and the other end of the spring 506 abuts against the pipe tail support 503. The end of the pin 505 corresponds to the opening of the metal pipe 601 and can slide axially to insert into or pull out of the opening of the metal pipe 601. The positioning assembly includes a pressing block 508 and a cylinder 509. The pressing block 508 is connected to the output shaft of the cylinder 509 and is located above the pipe end support 501.

[0065] Before expansion, insert the metal pipe 601 into the pipe hole of the flange 602 to form the metal pipe flange assembly 600 to be expanded. Place one end of the metal pipe 601 on the positioning block 502 of the pipe end support 501, so that the end of the metal pipe 601 and the flange 602 are placed in the front positioning groove 5041 of the positioning block 502 to prevent the metal pipe 601 from moving. Then place the other end of the metal pipe 601 in the rear positioning groove 5042 of the pipe tail support 503. Adjust the position of the metal pipe 601 so that it remains stable under the combined action of the pipe end support 501 and the pipe tail support 503. Hold the pin 505 by hand, overcome the elastic force of the spring 506, and push the pin 505 axially toward the pipe opening of the metal pipe 601 so that the end of the pin 505 is inserted into the pipe opening at the tail of the metal pipe 601. At this time, the spring 506 is compressed, which will generate an elastic force on the pin 505 toward the metal pipe 601, thereby pressing and positioning the metal pipe 601 axially.

[0066] When fixing the metal pipe flange assembly 600, the pneumatic system of the control equipment activates the cylinder 509, causing the output shaft of the cylinder 509 to extend downwards, driving the connected pressing block 508 to move downwards. When the pressing block 508 contacts the surface of the flange 602 of the metal pipe flange assembly 600, downward pressure is applied, pressing the flange 602 tightly onto the pipe end support 501. At this time, the metal pipe flange assembly 600 achieves omnidirectional stable fixing under the positioning action of the pipe end support 501, the positioning block 502, and the pipe tail support 503, as well as the axial pressing action of the pin 505 and the vertical pressing action of the pressing block 508, effectively preventing displacement or deformation due to uneven force during subsequent expansion.

[0067] After the metal pipe flange assembly 600 is fixed, the rotary drive device 300 and the moving device 200 of the eccentric expansion joint equipment can be started to expand the metal pipe 601 according to the preset process parameters. During the expansion joint process, the positioning fixture 500 must always keep the metal pipe flange assembly 600 stably fixed to ensure the expansion joint accuracy and quality.

[0068] After the expansion joint is completed, the pneumatic system of the control equipment is used to axially retract the cylinder 509, causing the pressing block 508 to move upward and away from the surface of the flange 602, thus releasing the vertical clamping force on the metal pipe flange assembly 600. Next, the pin 505 is held by hand, and the limiting block 507 is pulled outward to overcome the spring force of the spring 506, pulling the pin 505 out of the opening of the metal pipe 601, thus releasing the axial clamping and positioning of the metal pipe 601. Finally, the expanded metal pipe flange assembly 600 is removed from the positioning fixture 500.

[0069] In this embodiment, the first drive cylinder 203 is a pneumatic cylinder 509, the second drive cylinder 204 is a servo motor, and the rotary drive device 300 is a geared motor.

[0070] The first drive cylinder 203 is used to drive the first base plate 201 and the rotary drive device 300 located above the first base plate to move laterally, so that the eccentric mold 400 inserts or pulls out the metal tube 601. The cylinder 509, as the first drive cylinder 203, has the advantages of simple structure, reliable operation, convenient maintenance, low price and easy to realize automatic control, and can meet the requirements of stability and accuracy of the eccentric mold 400 in lateral movement.

[0071] The second drive cylinder 204 drives the second base plate 202 and its rotary drive device 300 to move longitudinally, thereby bringing the eccentric protrusion 401 of the eccentric mold 400 into contact with the inner wall of the metal tube 601. This movement distance is extremely small, approximately 1 mm. The servo motor possesses significant advantages such as extremely high control precision, low moment of inertia, fast positioning speed, wide speed range, and strong overload capacity. Using it as the second drive cylinder 204 enables high-precision positioning of the rotary drive device 300 during longitudinal movement, ensuring precise contact between the eccentric protrusion 401 and the inner wall of the metal tube 601.

[0072] The rotary drive unit 300 is used to drive the eccentric mold 400 to rotate. The geared motor has the characteristics of small size, light weight, high load capacity, long service life and smooth operation. Using it as the rotary drive unit 300 can stably drive the eccentric mold 400 to rotate, ensuring the smooth progress of the expansion process. At the same time, the use of a geared motor can also reduce the rotation speed and increase the torque, thereby better adapting to the expansion requirements of metal pipe flange assemblies 600 of different materials and specifications.

[0073] like Figure 10 As shown, a metal pipe flange assembly 600 with a double pipe structure is provided. Two pipe holes are symmetrically opened on the flange 602, and two independent metal pipes 601 are inserted into the corresponding pipe holes respectively. The ends of the metal pipes 601 are machined with internal threads 604, and an annular groove 603 is provided on the outside.

[0074] refer to Figure 11 - Figure 13 As shown, the process of eccentrically expanding the metal pipe flange assembly 600 to be expanded using the eccentric expansion equipment of the present invention is as follows:

[0075] First, an internal thread 604 and an annular groove 603 are machined at one end of the metal tube 601;

[0076] Next, the metal pipe 601 is inserted into the pipe hole of the flange 602 to form a metal pipe flange assembly 600 to be expanded; then, the assembly is placed on the positioning fixture 500 and fixed.

[0077] The longitudinal position of the rotary drive device 300 is adjusted by the moving device 200 so that the axis of the eccentric mold 400 coincides with the axis of one of the metal tubes 601.

[0078] Then, the moving device 200 is used again to push the rotary drive device 300 to move laterally, so that the eccentric mold 400 is inserted into the metal tube 601;

[0079] Next, the longitudinal position of the rotary drive device 300 is adjusted, and the eccentric mold 400 moves a distance d along the longitudinal direction so that the eccentric protrusion 401 of the eccentric mold 400 contacts the inner wall of the metal tube 601.

[0080] Start the rotary drive device 300 to make the eccentric mold 400 rotate inside the metal tube 601. Due to the contact between the eccentric protrusion 401 of the eccentric mold 400 and the inner wall of the metal tube 601, a squeezing effect is generated, which causes the inner wall of the metal tube 601 to deform, thereby achieving a tight connection between the metal tube 601 and the flange 602.

[0081] Finally, after the expansion joint is completed, the longitudinal and lateral positions of the rotary drive device 300 are adjusted by the moving device 200, so that the eccentric mold 400 exits the metal tube 601, and one cycle of the eccentric expansion joint process ends.

[0082] The eccentric expansion device of this invention expands metal pipes and flanges together, improving expansion efficiency and reducing manufacturing costs. Simultaneously, the mechanical expansion method avoids heat-affected zones and welding defects that may occur during welding, improving the connection strength and reliability of the metal pipe flange assembly 600. Furthermore, this device has wide applicability and can adapt to the expansion requirements of metal pipe flange assemblies 600 of different specifications and materials.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An eccentric expansion joint process, characterized in that, Using an eccentric expansion device, the eccentric expansion device includes a rotary drive device (300) and an eccentric mold (400), one end of the eccentric mold (400) is connected to the rotary drive device (300), and the other end of the eccentric mold (400) is provided with an eccentric protrusion (401), including the following steps: S1. Insert the metal pipe (601) into the pipe hole of the flange (602) to form the expansion assembly (600). S2. Fix the expansion joint component (600). S3. Adjust the position of the eccentric mold (400) so that its axis coincides with the axis of the metal tube (601), and insert the end of the eccentric mold (400) with the eccentric protrusion (401) into the metal tube (601); S4. Move the eccentric mold (400) a distance d along the radial direction of the metal tube (601) so that the eccentric protrusion (401) contacts the inner wall of the metal tube (601); S5. Start the rotary drive device (300) to drive the eccentric mold (400) to rotate, and squeeze the inner wall of the metal tube (601) through the eccentric protrusion (401) to make it plastically deform, so as to realize the connection between the metal tube (601) and the flange (602); S6, Exit the eccentric mold (400); In step S2, the assembly to be expanded (600) is fixed by a positioning fixture (500). The positioning fixture (500) includes a pipe end support (501), a positioning block (502), and a pipe tail support (503). The positioning block (502) is installed on the pipe end support (501). The positioning block (502) is provided with a front positioning groove (5041), and the pipe tail support (503) is provided with a rear positioning groove (5042). In step S2, the positioning fixture (500) also includes a pin (505) and a spring (506). Axial positioning is achieved by inserting the pin (505) into the opening of the metal tube (601). The pin (505) is kept in the inserted state under the action of the spring (506).

2. The eccentric expansion joint process according to claim 1, characterized in that, In step S1, before the metal tube (601) is inserted into the flange (602), an internal thread hole and a groove are machined at the end of the metal tube (601).

3. The eccentric expansion joint process according to claim 1, characterized in that: In step S2, the positioning fixture (500) further includes a pressing block (508) and a cylinder (509). The pressing block (508) is connected to the output shaft of the cylinder (509), and the pressing block (508) is driven by the cylinder (509) to press the flange (602).

4. The eccentric expansion joint process according to claim 3, characterized in that: In steps S3 and S4, the lateral insertion and longitudinal movement of the eccentric mold (400) are achieved by the moving device (200). The moving device (200) includes a first base plate (201), a second base plate (202), a first drive cylinder (203), and a second drive cylinder (204). The first drive cylinder (203) drives the first base plate (201) to move laterally; the second drive cylinder (204) drives the second base plate (202) to move longitudinally; and the rotation drive device (300) is installed on the second base plate (202).

5. The eccentric expansion joint process according to claim 4, characterized in that: The eccentric expansion device also includes a worktable (100), on which a first slide rail is provided, and a first base plate (201) is slidably mounted on the first slide rail. A second slide rail is provided above the first base plate (201), and a second base plate (202) is slidably mounted on the second slide rail.

6. The eccentric expansion joint process according to claim 5, characterized in that: The second base plate (202) is also provided with a support seat (301), which is located between the rotary drive device (300) and the positioning fixture (500). In step S5, the eccentric mold (400) is rotated and supported by the bearing (302) in the support seat (301).

7. The eccentric expansion joint process according to claim 5, characterized in that: The first drive cylinder is a pneumatic cylinder, the second drive cylinder is a servo motor, and the rotary drive device is a geared motor.

8. The eccentric expansion joint process according to claim 1, characterized in that: In step S4, the distance d ranges from 0.1mm to 0.3mm.

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