An expander device for a double expanded pipe

Abstract

This utility model belongs to the field of pipe manufacturing technology, specifically relating to an expansion joint device for double-expansion spiral pipes, including a clamping die assembly, a punching die assembly, and a connecting assembly. The clamping die assembly is used to clamp the pipe fitting and the flange to be expanded. The punching die assembly includes an expansion sleeve and an expansion core movably disposed within the expansion sleeve. The end of the expansion sleeve is provided with an expansion tube end, and the expansion core can move axially within the expansion sleeve to expand the expansion tube end. The shape of the expansion tube end is adapted to the shape of the pipe fitting expansion position. The expansion core is connected to the connecting assembly. The connecting assembly is used to connect to a power mechanism. This utility model achieves synchronous expansion joint of two pipes, avoiding the processing interference problem caused by step-by-step operation, significantly improving production efficiency. At the same time, this utility model has a compact structure, is easy to operate, reduces process complexity, and reduces production costs.

Description

Technical Field

[0001] This utility model relates to an expansion joint device for a double-expansion spiral tube, belonging to the field of pipe manufacturing technology. Background Technology

[0002] In the manufacturing of air conditioning systems, the expansion process of cooling bends is crucial. It involves mechanically expanding and deforming the aluminum tube to ensure a tight fit with the connecting components, thereby guaranteeing the system's sealing and structural stability. After expansion, grooves (such as threads or grooves) are usually machined on the tube ends for subsequent assembly. However, in double-tube expansion, due to the spatial constraints of the two tubes, simultaneous grooving after expansion can easily cause interference between the cutting tools or processing equipment, leading to processing difficulties or even failure. Currently, the industry's solution for double-tube expansion is mainly step-by-step processing: first, the first bend is expanded, and then its end is grooved; the second bend requires pre-grooving before assembly with the connecting components. However, because the inner diameter of the tube decreases after grooving, while the diameter of the tube expander used for expansion is fixed, if the tube diameter after grooving is smaller than the tube expander diameter, it is impossible to use the tube expander for expansion. In this case, welding is the only option, but welding is prone to thermal deformation, affecting sealing and strength. Since the two pipe fittings cannot be expanded or grooved simultaneously, they must be operated in steps, which leads to a longer production cycle and affects the overall manufacturing efficiency. Step-by-step operation means that multiple clamping and adjustment of the processing sequence are required. Moreover, relying on welding to replace expansion increases the complexity of the process and production costs.

[0003] Therefore, there is an urgent need to develop a dual-pipe synchronous expansion joint device to solve the problems of processing interference, low efficiency, and unstable process in the existing technology, and to meet the air conditioning industry's demand for high-precision and high-efficiency manufacturing. Utility Model Content

[0004] This invention addresses the problems of processing interference, low efficiency, and unstable process in existing dual-tube synchronous expansion joints by providing a dual-expansion spiral tube expansion joint device.

[0005] The technical solution of this utility model to solve the above-mentioned technical problems is as follows:

[0006] An expansion joint device for a double-expansion tube includes a clamping die assembly, a punching die assembly, and a connecting assembly. The clamping die assembly is used to clamp the pipe fitting and the flange fitting to be expanded. The punching die assembly includes an expansion sleeve and an expansion core movably disposed within the expansion sleeve. The end of the expansion sleeve is provided with an expansion tube end. The expansion core can move axially within the expansion sleeve to expand the expansion tube end. The end shape of the expansion tube end is adapted to the shape of the pipe fitting expansion position. The expansion core is connected to the connecting assembly. The connecting assembly is used to connect to a power mechanism.

[0007] The beneficial effects of the above-mentioned technical solution of this utility model are as follows: This utility model clamps the pipe fitting and the flange fitting to be expanded by the clamping mold assembly. The power mechanism drives the expansion sleeve of the punching die assembly to extend into the pipe fitting through the connecting assembly. The expansion core expands the expansion tube end to complete the expansion of the pipe fitting. The end shape of the expansion tube end is adapted to the shape of the expansion position of the pipe fitting, which ensures the accuracy and stability of the expansion and meets the needs of the air conditioning industry for high-precision and high-efficiency manufacturing. By adopting the method of expanding the expansion tube end with the expansion core, it can be ensured that the size of the expansion tube end when it is not expanded is smaller than the inner diameter of the pipe fitting after the groove is turned, which makes it convenient for the expansion tube end to penetrate into the pipe fitting to complete the expansion process.

[0008] This invention achieves synchronous expansion of two tubes through the above technical solution, avoiding the processing interference problem caused by step-by-step operation, and significantly improving production efficiency. At the same time, this invention has a compact structure, is easy to operate, reduces process complexity, and reduces production costs.

[0009] Based on the above technical solution, the present invention can be further improved as follows:

[0010] Furthermore, the expansion sleeve includes an expansion sleeve body, the expansion tube end is located at the end of the expansion sleeve body, and the expansion sleeve body has a cavity for accommodating the expansion core.

[0011] The beneficial effects of adopting the above-mentioned further technical solutions are: the expansion sleeve body is a cavity structure, which can accommodate the expansion core to move within it, so that the expansion core can move within the expansion sleeve and expand the expansion tube end to complete the expansion joint operation.

[0012] Furthermore, the expansion tube end includes multiple expansion tube flaps, which are arranged circumferentially, and the ends of the multiple expansion tube flaps are bent inward to form end holes.

[0013] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: the expansion tube end is designed with multiple expansion tube flaps, which are evenly distributed in the circumferential direction. This design makes it easier for the expansion tube end to open under the action of the expansion core, adapting to the expansion requirements of different pipe fittings; the design of expansion tube flaps also makes the expansion tube end more elastic, improves the expansion accuracy of the pipe fitting, and ensures that the expanded pipe fitting can maintain good sealing and structural stability; the ends of the multiple expansion tube flaps are bent inward to form end holes, which facilitates the expansion core to extend out from the end holes to open the expansion tube end.

[0014] Furthermore, the end of the expansion tube flap connected to the expansion sleeve body is provided with an arc-shaped transition section, and the middle part of the expansion tube flap is provided with an inward concave section.

[0015] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: the arc-shaped transition section design allows the expansion tube flap to transition more smoothly during the opening process, avoiding damage to the expansion tube flap due to stress concentration, improving the service life of the expansion joint device, and reducing the resistance to the expansion tube flap being opened; the concave section design of the expansion tube flap further enhances the elasticity of the expansion tube flap, reduces the resistance to the expansion tube flap being opened, and allows the expansion tube flap to be opened better when subjected to the opening force of the expansion core, further improving the accuracy and stability of the expansion joint.

[0016] Furthermore, the surfaces adjacent to the concave section of the expansion tube flap are provided with grooves.

[0017] The beneficial effects of adopting the above-mentioned further technical solution are as follows: The grooves on the adjacent surfaces of the concave section of the expansion tube flap not only further optimize the structural strength of the expansion tube flap but also improve its deformation capacity during the expansion process. The presence of the grooves allows the expansion tube flap to distribute stress more evenly when subjected to the expanding core's opening force, avoiding damage to the expansion tube flap caused by excessive local stress. Simultaneously, the grooves also increase the elastic deformation range of the expansion tube flap, improving its flexibility and further ensuring expansion accuracy. Furthermore, it reduces the amount of material used in components, saving costs.

[0018] Furthermore, the expansion core includes a core head and a pin disposed on the core head. The pin includes a columnar section and a pointed section. The diameter of the columnar section is larger than the diameter of the end hole of the expansion tube end, and the end diameter of the pointed section is smaller than the diameter of the end hole of the expansion tube end.

[0019] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: the diameter of the cylindrical section of the expansion core is larger than the diameter of the end hole of the expansion tube, which can play a guiding and positioning role during the movement of the expansion core, ensuring that the expansion core can accurately extend into the end hole of the expansion tube; while the end diameter of the tip section is smaller than the diameter of the end hole of the expansion tube, which allows the expansion core to smoothly pass through the end hole of the expansion tube and continue to move and expand the expansion tube flaps after passing through, thus completing the expansion joint operation, ensuring the accuracy of the expansion joint and improving the efficiency of the expansion joint.

[0020] Furthermore, the connecting assembly includes an upper section, a middle section, and a lower section. The upper section is connected to the power mechanism, the middle section is movably connected to the expansion sleeve body, and the lower section is connected to the core head of the expansion core.

[0021] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: the upper section of the connector is connected to the power mechanism, which can stably transmit power, enabling the expansion joint device to complete the expansion joint operation efficiently and accurately; the middle section of the connector is movably connected to the expansion sleeve body, which not only ensures that the expansion sleeve can move under the drive of the connecting component, but also allows the expansion sleeve to maintain a certain degree of flexibility during the expansion joint process, enabling it to drive the expansion core to move, so that it can generate relative movement with the expansion sleeve and thus open the expansion tube end; the lower section of the connector is connected to the core head of the expansion core, ensuring that the expansion core can move stably and open the expansion tube end to complete the expansion joint operation.

[0022] Furthermore, a limiting rod is provided on the outer side of the middle section of the connecting body, and a corresponding strip-shaped limiting hole is provided on the expansion sleeve body. The limiting rod is inserted into the limiting hole. A return spring is provided between the middle section of the connecting body and the expansion sleeve body, and the two ends of the return spring abut against the middle section of the connecting body and the expansion sleeve body, respectively.

[0023] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: the limiting rod is inserted into the limiting hole, and during the movement of the middle section of the connector, the limiting rod and the limiting hole can limit and guide the middle section of the connector, improving the stability and accuracy of the expansion joint; the setting of the return spring can provide a reverse thrust to the middle section of the connector after the expansion joint is completed, so as to drive the expansion core to return to its original position, preparing for the next expansion joint operation. At the same time, the return spring can also play a buffering role, reducing the impact on the expansion joint device and pipe fittings during the expansion joint process, protecting the expansion joint device and pipe fittings, and extending their service life.

[0024] Furthermore, the clamping mold assembly includes a first half mold and a second half mold, and a cavity for accommodating pipe fittings and flange fittings is formed between the first half mold and the second half mold.

[0025] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: the first and second halves of the clamping mold assembly can stably clamp the pipe fittings and the flanges to be expanded, ensuring that the pipe fittings and flanges will not move or deform during the expansion process, thereby guaranteeing the accuracy and stability of the expansion. The cavity formed between the first and second halves of the mold provides sufficient space for the expansion operation, allowing the expansion sleeve and expansion core to smoothly extend into the pipe fitting to complete the expansion. Furthermore, the design of the clamping mold facilitates the placement and removal of pipe fittings and flanges, and also makes disassembly and cleaning convenient, facilitating daily maintenance and upkeep of the expansion device and improving the service life of the clamping mold assembly.

[0026] The expansion method of this utility model using the expansion device with double expansion tubes as described above specifically includes the following steps:

[0027] Step S1: Grooving the pipe ends, grooving is performed on the pipes one and two to be expanded;

[0028] Step S2: Pipe bending process, bend the grooved pipes one and two respectively;

[0029] Step S3: Prepare the flange and insert the grooved ends of pipe one and pipe two into the mating holes of the flange.

[0030] Step S4: Place the flange and pipe one and pipe two as a whole into the cavity formed by the first half mold and the second half mold, and close the mold clamping assembly;

[0031] Step S5: The power mechanism drives the punching die assembly to move toward the clamping die assembly via the connecting component, so that the expansion end of the expansion sleeve extends into one of the pipe fittings;

[0032] Step S6: The power mechanism continues to drive the punching die assembly to move until the end face of the expansion sleeve is in contact with the end face of the clamping die assembly, at which point the expansion end of the expansion sleeve reaches the position to be expanded of the pipe fitting.

[0033] Step S7: The power mechanism continues to drive the connecting assembly to move. The expansion sleeve stops moving due to the obstruction of the clamping mold end face. The connecting assembly continues to move to compress the return spring. The expansion core continues to move towards the inside of the pipe under the drive of the connecting assembly.

[0034] Step S8: Driven by the connecting component, the expansion core continues to move towards the inside of the pipe, and the tip of the expansion core extends out from the end hole of the expansion sleeve.

[0035] Step S9: After the tip of the expansion core is fully extended out of the end hole of the expansion tube end, the columnar section of the expansion core continues to move outward from the expansion tube end, thereby opening the expansion tube flaps of the expansion tube end. The expansion tube flaps squeeze the inside of the fitting, causing the fitting to be squeezed and deformed, thereby fitting with the flange and completing the expansion connection of one of the fittings.

[0036] Step S10: The power mechanism is reset. The connecting component moves in the opposite direction under the action of the reset spring. The connecting component drives the expansion core to move in the opposite direction. The expansion core returns to the expansion sleeve. The expansion tube end of the expansion sleeve is elastically reset due to the loss of the radial spreading force of the expansion core. When the connecting component moves to the limit rod reaching the end of the limit hole, the connecting component drives the expansion sleeve to move, so that the expansion tube end of the expansion sleeve moves out of the pipe.

[0037] Step S11: Repeat steps S5-S10 above to complete the expansion joint of another pipe fitting.

[0038] The beneficial effects of the above-mentioned technical solution of this utility model are as follows: Before expanding the pipe fittings, this utility model performs grooving and bending operations first, and then, through the expansion equipment described above, it can achieve efficient and precise expansion of double-expanding grooving pipes. During the expansion process, the coordinated use of the expansion sleeve and the expansion core ensures the accuracy and stability of the expansion, avoiding the processing interference problems caused by step-by-step operations. The application of this expansion method and device will significantly improve the production efficiency and product quality of double-pipe expansion, providing strong technical support for the manufacturing of air conditioning systems. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0040] Figure 2 This is a schematic diagram of the overall structure of this utility model from another angle;

[0041] Figure 3 This is a top view of the present invention;

[0042] Figure 4 This is a schematic diagram of the overall structure of the punching die assembly of this utility model;

[0043] Figure 5 This is a front view of the punching die assembly of this utility model;

[0044] Figure 6 This is a cross-sectional view of the punching die assembly of this utility model;

[0045] Figure 7 This is a schematic diagram of the overall structure of the expansion sleeve of this utility model;

[0046] Figure 8 This is a schematic diagram of the overall structure of the expansion sleeve of this utility model from another angle;

[0047] Figure 9 This is a front view of the expansion sleeve of this utility model;

[0048] Figure 10 This is a schematic diagram of the overall structure of the expansion core of this utility model;

[0049] Figure 11 This is a schematic diagram of the overall structure of the punching die assembly and connecting assembly of this utility model;

[0050] Figure 12 for Figure 11 The main view;

[0051] Figure 13 for Figure 11 A sectional view;

[0052] Figure 14 This is a schematic diagram of the overall structure of the connecting component of this utility model;

[0053] Figure 15 This is another overall structural diagram of the connecting component of this utility model;

[0054] Figure 16 This is a schematic diagram of the overall structure of the connecting component and the expansion core of this utility model;

[0055] Figure 17 This is a schematic diagram of the expansion joint process according to an embodiment of the present utility model;

[0056] Figure 18 This is a schematic diagram of the overall structure of pipe one and pipe two according to an embodiment of the present utility model;

[0057] Figure 19 This is a schematic diagram of the structure of pipe one and pipe two after being expanded and connected with the flange according to an embodiment of the present utility model.

[0058] The reference numerals in the attached drawings are as follows: 1. Clamping mold assembly; 101. First half mold; 102. Second half mold; 2. Punching mold assembly; 21. Expansion sleeve; 211. Expansion sleeve body; 212. Expansion tube end; 213. Expansion tube flap; 2131. Arc-shaped transition section; 2132. Concave section; 2133. Groove; 214. Cavity; 215. End hole; 216. Limiting hole; 217. Limiting end face; 22. Expansion core; 221. Core head; 222. Ejector pin; 2221. Columnar section; 2222. Tip section; 3. Connecting assembly; 31. Upper section of connecting body; 32. Middle section of connecting body; 321. Threaded hole; 322. Limiting ring platform; 33. Lower section of connecting body; 4. Tube one; 5. Tube two; 6. Flange; 61. Butt hole. Detailed Implementation

[0059] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0060] See Figure 1 -to Figure 19 An expansion joint device for a double expansion tube includes a clamping die assembly 1, a punching die assembly 2, and a connecting assembly 3.

[0061] The clamping mold assembly 1 is used to clamp the pipe fitting and the flange 6 to be expanded. Specifically, in this embodiment, the clamping mold assembly 1 includes a first half mold 101 and a second half mold 102. A cavity for accommodating the pipe fitting and the flange 6 is formed between the first half mold 101 and the second half mold 102. In this embodiment, the pipe fitting is first grooved and bent before expansion. Therefore, the shape of the inner wall of the first half mold 101 and the second half mold 102 is adapted to the shape of the pipe fitting after bending.

[0062] The punching die assembly 2 includes an expansion sleeve 21 and an expansion core 22 movably disposed within the expansion sleeve 21. Specifically, the expansion sleeve 21 includes an expansion sleeve body 211, with an expansion tube end 212 at one end of the expansion sleeve body 211. The expansion sleeve body 211 has a cavity 214 for accommodating the expansion core 22. The expansion sleeve body 211 is open at one end away from the expansion tube end 212. The expansion core 22 can move axially within the expansion sleeve 21 to expand the expansion tube end 212. The expansion core 22 is connected to the connecting assembly 3. The shape of the end of the expansion tube end 212 is adapted to the shape of the expansion joint position of the pipe fitting.

[0063] Specifically, the expansion end 212 includes multiple expansion flaps 213, which are arranged circumferentially. The ends of the multiple expansion flaps 213 are bent inward to form end holes 215. The shape of the outer side of the end of the expansion flap 213 is adapted to the shape of the inner wall of the expansion joint position of the pipe fitting. When the expansion core 22 moves within the sleeve and extends out from the end hole 215 of the expansion end 212, the ends of the expansion flaps 213 are opened up. The ends of the expansion flaps 213 cause the inner wall of the expansion joint position of the pipe fitting to deform, thereby expanding the pipe fitting onto the flange 6.

[0064] The end of the expansion tube flap 213 connected to the expansion sleeve body 211 is provided with an arc-shaped transition section 2131, and the inner side of the expansion tube end 212 of the arc-shaped transition section 2131 is recessed. Therefore, when each expansion flap 213 of the expansion tube end 212 deforms under the action of the expansion core 22, the arc-shaped transition section 2131 can facilitate the deformation of the expansion flap 213, reduce the difficulty of deformation caused by the internal stress of the expansion flap 213, or even the damage to the expansion flap 213. The expansion flap 213 has a concave section 2132 in the middle. Furthermore, the surface adjacent to the concave section 2132 of the expansion flap 213 has a groove 2133. The design of the concave section 2132 and the groove 2133 further enhances the elasticity of the expansion flap 213, reduces the resistance of the expansion flap 213 being stretched, and enables the expansion flap 213 to be stretched better when subjected to the stretching force of the expansion core 22, further improving the accuracy and stability of the expansion joint.

[0065] The expansion core 22 includes a core head 221 and a pin 222 disposed on the core head 221. The pin 222 includes a columnar section 2221 and a tip section 2222. The columnar section 2221 is fixedly connected to the core head 221. The tip section 2222 is disposed at the end of the columnar section 2221. The diameter of the columnar section 2221 is larger than the diameter of the end hole 215 of the expansion tube end 212, and the end diameter of the tip section 2222 is smaller than the diameter of the end hole 215 of the expansion tube end 212.

[0066] The connecting component 3 is used to connect with a power mechanism, which drives the connecting component 3 to move, thereby driving the punching die component 2 to move and achieve the expansion joint of the pipe fitting. This utility model does not specifically limit the power mechanism; in this embodiment, the power mechanism is a punching die cylinder (not shown in the figure), and the piston rod end of the punching die cylinder is connected to the connecting component 3. Specifically, the connecting component 3 includes an integrally formed upper connecting body 31, a middle connecting body 32, and a lower connecting body 33. The upper connecting body 31 is connected to the piston rod end of the punching die cylinder, the middle connecting body 32 is movably connected to the expansion sleeve body 211, and the lower connecting body 33 is connected to the core head 221 of the expansion core 22.

[0067] A limiting rod (not shown in the figure) is provided on the outer side of the middle section 32 of the connecting body. Specifically, threaded holes 321 are provided on both sides of the middle section 32 of the connecting body. The limiting rod is threaded into the threaded holes 321. The expansion sleeve body 211 is provided with a corresponding strip-shaped limiting hole 216. The limiting rod is inserted into the limiting hole 216. Specifically, after the middle section 32 of the connecting body is inserted into the expansion sleeve 21, the limiting rod passes through the limiting block and is screwed into the threaded hole 321. The movable connection between the middle section 32 of the connecting body and the expansion sleeve 21 is achieved by tightening the limiting rod. A return spring (not shown in the figure) is provided between the middle section 32 of the connecting body and the expansion sleeve body 211. A limiting ring platform 322 is provided at the bottom of the middle section 32 of the connecting body. A limiting end face 217 is provided at the bottom of the inner wall of the expansion sleeve body 211. The two ends of the return spring abut against the limiting ring platform 322 of the middle section 32 of the connecting body and the limiting end face 217 of the expansion sleeve body 211, respectively.

[0068] This utility model embodiment also relates to an expansion method using the above-mentioned double-expansion tube expansion device. In this embodiment, the two pipe fittings to be expanded are denoted as pipe one 4 and pipe two 5, wherein the diameter of pipe one 4 is larger than the diameter of pipe two 5. The expansion method specifically includes the following steps:

[0069] Step S1: Pipe end grooving. Grooving equipment is used to groove the pipe 4 and pipe 5 to be expanded.

[0070] Step S2: Pipe bending process, using pipe bending equipment to bend pipe 4 and pipe 5 after grooving respectively;

[0071] Step S3: Prepare flange 6, and insert the grooved ends of pipe 4 and pipe 5 into the mating hole 61 of flange 6.

[0072] Step S4: Place the flange 6, pipe 1 4, and pipe 2 5 into the cavity formed by the first half mold 101 and the second half mold 102, and close the mold clamping assembly 1;

[0073] Step S5: The piston rod of the punch cylinder extends, driving the connecting assembly 3 to move, and through the connecting assembly 3, the punch assembly 2 moves as a whole toward the clamping assembly 1 until the expansion tube end 212 of the expansion sleeve 21 extends into one of the pipes. Since a return spring is provided between the connecting body middle section 32 of the connecting assembly 3 and the expansion sleeve 21, when the piston rod of the punch cylinder drives the connecting assembly 3 to move, the connecting body middle section 32 of the connecting assembly 3 acts on the limiting end face 217 of the inner wall of the expansion sleeve 21 through the return spring, thereby driving the expansion sleeve 21 to move.

[0074] Step S6: The piston rod of the punch cylinder continues to extend, driving the connecting assembly 3 and the punch assembly 2 to move until the end face of the expansion sleeve 21 is in contact with the end face of the clamping assembly 1 (i.e. the end faces of the first half mold 101 and the second half mold 102 facing the end of the expansion sleeve 21), and the expansion tube end 212 of the expansion sleeve 21 reaches the position to be expanded of the pipe fitting.

[0075] Step S7: The piston rod of the punch cylinder continues to extend, driving the connecting assembly 3 to move. The expansion sleeve 21 stops moving due to the obstruction of the clamping die end face. The connecting assembly 3 compresses the reset spring, and the expansion core 22 continues to move toward the tube under the drive of the connecting assembly 3.

[0076] Step S8: Driven by the connecting component 3, the expansion core 22 continues to move toward the inside of the tube. The tip section 2222 of the expansion core 22 extends out from the end hole 215 of the expansion tube end 212 of the expansion sleeve 21, gradually opening the expansion tube flap 213 of the expansion tube end 212.

[0077] Step S9: After the tip section 2222 of the expansion core 22 is fully extended out of the end hole 215 of the expansion tube end 212, the columnar section 2221 of the expansion core 22 continues to move outward from the expansion tube end 212, thereby fully opening the expansion tube flap 213 of the expansion tube end 212. The expansion tube flap 213 squeezes the inside of the pipe fitting, causing the pipe fitting to be squeezed and deformed, thereby fitting with the flange 6 and completing the expansion connection of one of the pipe fittings.

[0078] Step S10: The piston rod of the die cylinder retracts, and the connecting assembly 3 moves in the opposite direction under the action of the return spring. The connecting assembly 3 drives the expansion core 22 to move in the opposite direction. The expansion core 22 returns to the expansion sleeve 21. The expansion tube end 212 of the expansion sleeve 21 elastically resets due to the loss of the radial spreading force of the expansion core 22. When the return spring is fully restored and the connecting assembly 3 moves to the end of the limit hole 216, the piston rod of the die cylinder continues to retract, driving the connecting assembly 3 to move. The connecting assembly 3 drives the expansion sleeve 21 to move, so that the expansion tube end 212 of the expansion sleeve 21 moves out of the tube.

[0079] Step S11: Repeat steps S5-S10 above to complete the expansion joint of another pipe fitting.

[0080] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An expansion joint device for a double-expansion spiral tube, characterized in that, The assembly includes a clamping mold assembly (1), a punching mold assembly (2), and a connecting assembly (3); the clamping mold assembly (1) is used to clamp the pipe fitting and the flange fitting (6) to be expanded; the punching mold assembly (2) includes an expansion sleeve (21) and an expansion core (22) movably disposed in the expansion sleeve (21), the end of the expansion sleeve (21) is provided with an expansion tube end (212), the expansion core (22) can move axially within the expansion sleeve (21) to open the expansion tube end (212), the end shape of the expansion tube end (212) is adapted to the shape of the pipe fitting expansion position, and the expansion core (22) is connected to the connecting assembly (3); the connecting assembly (3) is used to connect to the power mechanism.

2. The expansion joint device for double-expansion spiral tubes according to claim 1, characterized in that, The expansion sleeve (21) includes an expansion sleeve body (211), the expansion tube end (212) is located at the end of the expansion sleeve body (211), and the expansion sleeve body (211) has a cavity (214) for accommodating the expansion core (22).

3. The expansion joint device for double-expansion spiral tubes according to claim 2, characterized in that, The expansion tube end (212) includes a plurality of expansion tube flaps (213), which are arranged circumferentially, and the ends of the plurality of expansion tube flaps (213) are bent inward to form end holes (215).

4. The expansion joint device for double-expansion spiral tubes according to claim 3, characterized in that, The end of the expansion tube flap (213) connected to the expansion sleeve body (211) is provided with an arc-shaped transition section (2131).

5. The expansion joint device for double-expansion spiral tubes according to claim 4, characterized in that, The expansion valve (213) has a concave section (2132) in the middle.

6. The expansion joint device for a double-expansion spiral tube according to claim 3, 4 or 5, characterized in that, The expansion core (22) includes a core head (221) and a pin (222) disposed on the core head (221). The pin (222) includes a columnar section (2221) and a tip section (2222). The diameter of the columnar section (2221) is larger than the diameter of the end hole (215) of the expansion tube end (212), and the end diameter of the tip section (2222) is smaller than the diameter of the end hole (215) of the expansion tube end (212).

7. The expansion joint device for a double-expansion spiral tube according to claim 6, characterized in that, The connecting component (3) includes an upper section (31), a middle section (32), and a lower section (33). The upper section (31) is connected to the power mechanism, the middle section (32) is movably connected to the expansion sleeve body (211), and the lower section (33) is connected to the core head (221) of the expansion core (22).

8. The expansion joint device for double-expansion spiral tubes according to claim 7, characterized in that, A limiting rod is provided on the outer side of the middle section (32) of the connecting body, and a corresponding strip-shaped limiting hole (216) is provided on the expansion sleeve body (211), and the limiting rod is inserted into the limiting hole (216).

9. The expansion joint device for a double-expansion spiral tube according to claim 7, characterized in that, A return spring is provided between the middle section (32) of the connector and the expansion sleeve body (211), with the two ends of the return spring abutting against the middle section (32) of the connector and the expansion sleeve body (211) respectively.

10. The expansion joint device for a double-expansion spiral tube according to claim 1, characterized in that, The clamping assembly (1) includes a first half mold (101) and a second half mold (102), and a cavity for accommodating the pipe fitting and the flange (6) is formed between the first half mold (101) and the second half mold (102).

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