An expanding device and expanding method for manufacturing PVC-O pipe

Abstract

The application relates to the technical field of plastic pipe processing, and discloses an expanding device and an expanding method for manufacturing PVC-O pipes, which comprise a conveying device for conveying the pipes, a flaring die, a conical flaring core, a driving piece for pushing the flaring core to be inserted into the flaring die, and a heating assembly for heating the pipes, and the driving end of the driving piece is fixedly connected with the flaring core; a cavity is arranged in the flaring core; an annular notch is arranged on the outer surface of the flaring core; a deformable sealing film is fixedly arranged at the notch; connecting rods are fixedly arranged on the two sides of the cavity; and extrusion assemblies are arranged on the surfaces of the connecting rods and correspond to the notch. The mechanical radial fixed-point supporting is adopted to replace the traditional air pressure forming, the pipe wall is accurately pressed into a die forming groove, the pipes are prevented from being excessively stretched at the sealing ring groove, the wall thickness is prevented from being uneven, the strength of the socket structure is improved, and the generation of the pressure-bearing burst problem can be effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of plastic pipe processing technology, specifically to an expansion device and method for manufacturing PVC-O pipes. Background Technology

[0002] PVC-O pipe, or biaxially oriented polyvinyl chloride pipe, is formed by bidirectional stretching of PVC-U pipe in both the axial and circumferential directions. It is widely used in fluid transportation engineering. To save construction costs and ensure the sealing of pipe joints, PVC-O pipes often omit matching fittings and directly achieve a plug-in seal by flaring the pipe ends. The existing flaring process involves first heating the section to be flared to a thermoplastic state, then axially extruding it through a flaring mold. The extrusion force from the moving mold causes the pipe end to radially expand and form the shape. After cooling and solidification, it is demolded to complete the processing. This process has significant drawbacks: the PVC-O pipe molecules are biaxially oriented and shaped, making them prone to radial shrinkage after heating. This not only affects the accuracy of the flaring process but also significantly reduces production efficiency.

[0003] In the production process of PVC-O pipes, in order to facilitate pipe connection, a socket structure is usually processed at the end of the pipe. This structure generally includes a groove for placing a rubber sealing ring and a protrusion for positioning or reinforcement.

[0004] Currently, in the existing PVC-O pipe flaring and forming processes, for the processing of complex cross-sections (such as sealing ring grooves, bosses, etc.) at the socket, the main process route is "heated core pre-expansion + internal air pressure assisted forming". That is, the pipe end is first heated and initially expanded by the heating core, and then compressed air is introduced into the pipe. The fluid characteristics of the gas are used to press the softened pipe wall against the inner wall of the external cooling and shaping mold, thereby replicating the groove and protrusion shape on the mold, such as the flaring device and flaring method of PVC-O pipe disclosed in CN105216294B.

[0005] However, pneumatic forming involves flexible force application, where gas tends to expand in the direction of least resistance. When a deep sealing groove needs to be formed, the pipe material must undergo severe radial tensile deformation to conform to the protrusion of the mold. Because the gas pressure distribution is uniform but lacks axial mechanical restraint, the material is prone to excessive stretching at the root of the groove, resulting in a significant reduction in wall thickness at that point. This not only reduces the pressure resistance of the socket but also makes it a weak point prone to bursting during subsequent hydrostatic testing or long-term operation. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies and solve the aforementioned technical problems of PVC-O pipes, such as the tendency for radial shrinkage to occur after heating due to biaxial orientation of the molecule and the tendency for uneven wall thickness, poor strength, and easy bursting of the gas-pressurized sealing ring groove, this invention proposes an expansion device and expansion method for manufacturing PVC-O pipes.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an expansion device for manufacturing PVC-O pipes, comprising a conveying device for conveying the pipe, a flaring mold, a conical flaring core, a driving component for pushing the flaring core into the flaring mold, and a heating assembly for heating the pipe. The driving end of the driving component is fixedly connected to the flaring core. The flaring core has an internal cavity, and its outer surface has an annular notch. A deformable sealing membrane is fixed at the notch. Connecting rods are fixed on both sides of the cavity. A pressing assembly is provided on the surface of the rod corresponding to the notch. The pressing assembly includes several pressing blocks 1 and 2 distributed in a ring around the circumference, and the pressing blocks 1 and 2 are arranged alternately. A pushing assembly is provided on the surface of the connecting rod. The pushing assembly is used to drive the pressing blocks 1 and 2 to extend radially outward to support the sealing film to form an annular protrusion, or to retract radially inward to be housed in the cavity. The flaring mold includes upper and lower shells, and electric push cylinders 4 are respectively provided on the outer side of the two shells. The driving end of the electric push cylinder 4 is fixedly connected to the adjacent shell.

[0008] By adopting the above technical solution, a cooling chamber is provided inside the flaring mold. The cooling chamber and the cavity are respectively provided with an input end and an output end. The input end and the output end are used to circulate and connect to the refrigeration equipment. The refrigeration equipment can circulate and deliver the refrigeration medium into the cooling chamber and the cavity to accelerate the cooling and forming of the pipe.

[0009] Preferably, the pushing assembly includes several electric push cylinders 1 and 2, which are respectively distributed in a circumferential ring and fixed on the connecting rod. The driving end of the electric push cylinder 1 is fixedly connected to the extrusion block 1, and the driving end of the electric push cylinder 2 is fixedly connected to the extrusion block 2.

[0010] Preferably, the pushing assembly includes a first ring and a second ring sleeved on the connecting rod, the first ring and the first extrusion block are hinged together by a first connecting rod, and the second ring and the second extrusion block are hinged together by a second connecting rod.

[0011] Preferably, the first ring and the second ring are respectively provided with two sets located on both sides of the center point of the first extrusion block or the second extrusion block. An adjustment component is installed on the connecting rod. The adjustment component includes a slot opened on the connecting rod and an installation slot opened on the upper and lower sides of the inner wall of the first ring and the second ring. Two sets of sliding blocks are slidably connected inside the slot, and a bidirectional lead screw is threadedly connected to the center of the two sliding blocks. A motor is fixedly installed on one side of the slot. The drive end of the motor is fixedly connected to one end of the bidirectional lead screw. A miniature electric push cylinder is embedded and fixedly installed above and below the sliding block. A locking block is slidably arranged inside the installation slot. An elastic element is fixed between the locking block and the installation slot. A slot for the drive end of the miniature electric push cylinder is provided on the side of the locking block facing the miniature electric push cylinder. An opening is opened on the upper and lower sides of the slot. The width of the opening is smaller than the diameter of the locking block and larger than the diameter of the drive end of the miniature electric push cylinder. A plurality of limiting grooves for the locking block to be inserted are provided on the surface of the opening.

[0012] Preferably, the flared core includes a main body with a rear opening. A connecting plate is provided inside the main body near the opening. The connecting rod is a spring telescopic rod used to connect the main body and the connecting plate and apply elastic force to the connecting plate so that it abuts against the inner wall of the opening of the main body. Retractable elastic rods are fixed between the first ring and the second ring and the connecting rod, respectively. A protruding layer is fixed on the outer side of the first ring. A limiting protrusion is fixed on the movement trajectory of the protruding layer inside the main body. A T-shaped extrusion rod is provided through the surface of the connecting plate on one side corresponding to the protruding layer. An elastic element is sleeved in the area of ​​the extrusion rod inside the main body.

[0013] Preferably, a second protrusion is fixedly provided on the outer side of the main body, and a second limiting protrusion is fixedly provided on the inner wall of the shell corresponding to the second protrusion.

[0014] Preferably, a fixed platform is provided on the outer side of the driving component, and both the driving component and the electric push cylinder four are fixedly connected to the fixed platform. An electric push cylinder three is fixedly provided on one side of the fixed platform. The heating assembly is provided on the driving end of the electric push cylinder three. The heating assembly includes a fixed panel fixedly connected to the driving end of the electric push cylinder three. Two sets of heating cylinders with different diameters are concentrically arranged on the side wall of the fixed panel.

[0015] Preferably, a connecting post is fixed at the center of the fixed panel, and a support cylinder and an electromagnet are respectively provided at the front end of the connecting post and the flared core. The electromagnets are respectively embedded and fixed at the front end of the connecting post and the flared core. The two support cylinders are made of ferromagnetic material, and the side walls of the two support cylinders are provided with annular grooves. A ring body three is inserted into the two annular grooves. The two ring bodies three are respectively fixedly connected to the connecting post and the flared core. An electric push cylinder five is embedded and fixed at the front end of the connecting post.

[0016] Preferably, a conveying assembly is provided on the fixed platform. The conveying assembly includes an electric slide table, which is fixedly mounted on the fixed platform. An electric push cylinder six is ​​fixedly mounted above the slider of the electric slide table. A bearing seat is fixedly mounted on the drive end of the electric push cylinder six, and a bearing groove is provided on the top of the bearing seat.

[0017] This invention provides an expansion device and method for manufacturing PVC-O pipes. It has the following advantages: 1. This invention replaces traditional pneumatic forming with mechanical radial fixed-point support, accurately pressing the pipe wall into the forming groove of the mold, avoiding excessive stretching of the pipe material and uneven wall thickness at the sealing ring groove, improving the strength of the socket structure, and effectively reducing the occurrence of pressure bursting problems.

[0018] 2. The present invention is equipped with a reusable support cylinder tooling. During the heating stage, the support tube body prevents the PVC-O pipe from shrinking radially due to heat. The processes are processed in parallel and the support cylinder can be recycled and reused, which improves production efficiency and eliminates the need for manual operation. Attached Figure Description

[0019] Figure 1 This is a perspective view of the present invention; Figure 2 This is a schematic diagram of the flaring mold structure of the present invention; Figure 3 This is a schematic diagram of the internal structure of the flared core of the present invention; Figure 4 This is a schematic diagram of the pushing component structure of the present invention; Figure 5 This is a schematic diagram of the adjustment component structure of the present invention; Figure 6 This is another schematic diagram of the pushing component of the present invention; Figure 7 This is a schematic diagram of the structure of electric push cylinder one and electric push cylinder two of the present invention; Figure 8 This is another schematic diagram of the pushing component of the present invention; Figure 9 This is another schematic diagram of the adjustment component of the present invention; Figure 10 This is a schematic diagram of the conveying component structure of the present invention; Figure 11 This is a schematic diagram of the heating component structure of the present invention; Figure 12 This is a schematic diagram of the flared core and support cylinder structure of the present invention.

[0020] The diagram exaggerates the spacing or dimensions between parts to show their positions; the diagram is for illustrative purposes only.

[0021] Among them, 1. conveying device; 2. flaring mold; 21. housing; 22. electric push cylinder four; 3. Flared core; 31. Main body; 32. Connecting plate; 33. Extrusion rod; 34. Elastic element two; 35. Protruding layer two; 36. Limiting protrusion two; 4. Sealing membrane; 5. Connecting rod; 6. Extrusion assembly; 601. Extrusion block one; 602. Extrusion block two; 7. Push the components; 71A, Electric Cylinder One; 72A, Electric Cylinder Two; 71B, Ring Body 1; 72B, Link 1; 73B, Ring Body 2; 74B, Link 2; 75B, Elastic Tie Rod; 76B, Raised Layer 1; 77B, Limiting Raised Layer 1; 8. Adjustment component; 802. Sliding block; 803. Two-way lead screw; 804. Motor; 805. Miniature electric cylinder; 806. Mounting slot; 807. Locking block; 808. Elastic element one; 809. Slot; 810. Limiting slot; 9. Drive unit; 10. Fixed platform; 11. Electric push cylinder III; 12. Heating assembly; 121. Fixing panel; 122. Heating cylinder; 123. Connecting column; 13. Electromagnet; 14. Support cylinder; 15. Annular groove; 16. Ring body three; 17. Electric pusher cylinder five; 18. Conveying assembly; 181. Electric slide table; 182. Electric pusher cylinder six; 183. Bearing seat. Detailed Implementation

[0022] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1, please refer to the appendix. Figure 1 -Appendix Figure 9This invention provides an expansion device for manufacturing PVC-O pipes, including a conveying device 1 for conveying the pipe, a flaring mold 2, a conical flaring core 3, a driving component 9 for pushing the flaring core 3 into the flaring mold 2, and a heating assembly 12 for heating the pipe. The driving component 9 can be a hydraulic cylinder, a pneumatic cylinder, or an electric push rod, and the driving end of the driving component 9 is fixedly connected to the flaring core 3. The flaring core 3 has a cavity inside, and an annular notch is opened on the outer surface of the flaring core 3. A deformable sealing membrane 4 is fixed at the notch. Connecting rods 5 are fixed on both sides of the cavity, and the surface of the connecting rods 5 is provided with extrusion clamps corresponding to the notch. Component 6, the extrusion component 6 includes several extrusion blocks 601 and 602 distributed in a ring around the circumference, and the extrusion blocks 601 and 602 are arranged alternately. The surface of the connecting rod 5 is provided with a pushing component 7, which is used to drive the extrusion blocks 601 and 602 to extend radially outward to support the sealing film 4 to form an annular protrusion, or to retract radially inward to be housed in the cavity. The inner wall of the flaring mold 2 is provided with an annular forming groove. The sealing film 4 is made of high-temperature resistant silicone rubber or fluororubber, which is not easy to adhere to molten PVC, and the outer wall can be sprayed with a high-temperature resistant silicone oil release coating to form an isolation oil film under high temperature each time the flaring is carried out.

[0024] Specifically, the pipe is placed on the conveying device 1 and transported to the flaring mold 2. One end of the pipe is inserted into the flaring mold 2 and heated by the heating component 12. After heating, the driving component 9 pushes the flaring core 3 into the pipe, squeezing the pipe so that the part of the pipe in contact with the flaring core 3 expands outward and is pressed against the inner wall of the flaring mold 2. When the extrusion component 6 moves to the corresponding forming groove, the pushing component 7 drives the pressure block 1 and the extrusion block 2 602 to extend radially outward to support the sealing membrane 4 and form an annular protrusion. This precisely presses the softened pipe wall into the forming groove inside the inner wall of the flaring mold 2, thus producing the socket sealing ring in one operation. After the groove and positioning boss structure is formed, the extrusion component 6 retracts radially into the cavity of the flared core 3, the sealing film 4 returns to its original state, the driving component 9 drives the flared core 3 to exit the pipe, and the flared mold 2 can be opened separately to complete the unloading of the pipe. This invention abandons the traditional pneumatic flexible pressure application method and relies on the extrusion block to radially support the sealing film 4 to achieve the forming of the groove in the pipe. The extrusion force is directed to the corresponding area of ​​the forming groove, avoiding excessive stretching and thinning of the material at the groove position of the pipe sealing ring. The wall thickness consistency of the socket is greatly improved, which solves the defects of weak pressure bearing and pressure test bursting in the groove part from the root, and improves the pressure resistance and service life of the PVC-O pipe socket structure.

[0025] Example 2, please refer to the appendix. Figure 6 -Appendix Figure 7This embodiment is one implementation of the pushing component 7. The pushing component 7 includes several electric push cylinders 71A and 72A that are respectively distributed in a circumferential ring and fixed on the connecting rod 5. The driving end of the electric push cylinder 71A is fixedly connected to the extrusion block 601, and the driving end of the electric push cylinder 72A is fixedly connected to the extrusion block 602.

[0026] Specifically, during use, the electric pusher cylinder 71A pushes the extrusion block 601 to move outward to its maximum extent, leaving a gap between adjacent extrusion blocks 601 for the extrusion block 602 to move. Then, the electric pusher cylinder 72A extends and pushes the extrusion block 602 to the gap between the extrusion blocks 601, thereby combining the extrusion blocks 601 to form an annular protrusion. After use, the electric pusher cylinder 72A first retracts to reset the extrusion blocks, and then the electric pusher cylinder 71A retracts to reset the extrusion block 601, so that the extrusion assembly 6 is housed in the cavity, thereby reducing the volume and facilitating the removal of the pipe.

[0027] Please see the appendix Figure 2 The flaring mold 2 includes two housings 21, and electric push cylinders 22 are respectively provided on the outer side of the two housings 21. The driving end of the electric push cylinders 22 is fixedly connected to the adjacent housing 21.

[0028] Specifically, the electric push cylinder 22 drives the housing 21 to move up and down. The electric push cylinder 22 extends so that the two housings 21 can close to expand the pipe. After the expansion is completed, the electric push cylinder 22 retracts to open the flaring mold 2 so that the flared pipe end can be moved out of the flaring mold 2.

[0029] Example 3, please refer to the appendix. Figure 3 -Appendix Figure 5 This embodiment is another implementation of the pushing component 7. The pushing component 7 includes a ring body 71B located on both sides of the extrusion block 601 and a ring body 73B located on both sides of the extrusion block 602. A connecting rod 72B is hinged between the ring body 71B and the extrusion block 601, and a connecting rod 74B is hinged between the ring body 73B and the extrusion block 602. An adjusting component 8 for adjusting the distance between the two ring bodies 71B and the distance between the two ring bodies 73B is installed on the connecting rod 5.

[0030] Specifically, during use, the adjusting component 8 drives the two ring bodies 71B to move relative to each other, reducing the distance between them. When the ring body 71B moves, it pushes the extrusion block 601 to move outward through the connecting rod 72B. Then, the adjusting component 8 drives the ring body 73B to move, reducing the distance. The ring body 73B drives the extrusion block 602 to move outward through the connecting rod 74B, causing the extrusion block 601 and the extrusion block 602 to extend and form an annular protrusion. After use, the adjusting component 8 drives the two ring bodies 73B and the ring body 71B to move towards each other in sequence, increasing the distance, and causing the extrusion block 602 and the extrusion block 601 to retract inward and be stored in the cavity in sequence.

[0031] Please see the appendix Figure 4 -Appendix Figure 5 The adjusting component 8 includes a slot on the connecting rod 5 and mounting grooves 806 on the upper and lower sides of the inner walls of ring 1 71B and ring 2 73B. Two sets of sliding blocks 802 are slidably connected inside the slot, and a double-acting screw 803 is threadedly connected to the center of each sliding block 802. A motor 804 is fixedly mounted on one side of the slot. The drive end of the motor 804 is fixedly connected to one end of the double-acting screw 803, and the other end of the double-acting screw 803 is rotatably connected to the connecting rod 5. Miniature electric cylinders 805 are embedded and fixedly mounted above and below each sliding block 802. The mounting groove 806 contains... A sliding locking block 807 is provided, and an elastic element 808 is fixed between the locking block 807 and the mounting groove 806. The elastic element 808 can be a steel leaf spring, a coil spring, a torsion bar spring, a rubber spring, etc., preferably a coil spring. The side of the locking block 807 facing the micro electric push cylinder 805 is provided with a slot 809 for the drive end of the micro electric push cylinder 805 to be inserted. Openings are respectively opened on the upper and lower sides of the slot. The width of the opening is smaller than the diameter of the locking block 807 and larger than the diameter of the drive end of the micro electric push cylinder 805. Several limiting grooves 810 for the locking block 807 to be inserted are provided on the surface of the opening.

[0032] Specifically, the locking block 807 slides out of the mounting groove 806 and inserts into the corresponding limiting groove 810 through the elastic force of the elastic element 808, limiting the ring body 71B and the ring body 73B. When the position of the ring body 71B or the ring body 73B needs to be adjusted, the motor 804 drives the bidirectional lead screw 803 to rotate, causing the two sliding blocks 802 to move synchronously in opposite directions or in opposite directions, so that the sliding blocks 802 move to the limiting groove 810 inside the two ring bodies 71B or the two ring bodies 73B. Then, the micro electric push cylinder 805 extends so that its driving end passes through the opening and inserts into the slot 809, thus locking the ring body. After block 807 pushes out of the limiting groove 810, motor 804 drives sliding block 802 to move. At this time, due to the insertion and cooperation of micro electric push cylinder 805 and slot 809, sliding block 802 moves to drive the corresponding ring body to move. After the extrusion block 1 601 and extrusion block 2 602 extend outward to the maximum extent, they stop moving. At this time, micro electric push cylinder 805 retracts, causing block 807 to re-insert into the corresponding limiting groove 810, thereby limiting the corresponding ring body at a certain degree. This allows for adjustment of the spacing between ring body 1 71B or ring body 2 73B, and achieves the limitation of ring body 1 71B or ring body 2 73B.

[0033] Example 4, please refer to the appendix. Figure 8 -Appendix Figure 9 This embodiment is another implementation of the pushing component 7. The pushing component 7 includes a ring body 71B and a ring body 73B sleeved on the connecting rod 5. A connecting rod 72B is hinged between the ring body 71B and the extrusion block 601. The connection point between the connecting rod 72B and the extrusion block 601 is located at the center of the inner side of the extrusion block. A connecting rod 74B is hinged between the ring body 73B and the extrusion block 602. The connection point between the connecting rod 74B and the extrusion block 602 is located at the center of the inner side of the extrusion block. A U-shaped opening is provided at one end of the connecting rod 74B corresponding to the elastic pull rod 75B. The elastic pull rod 75B is located inside the U-shaped opening. The flared core 3 includes a main body 31 with a rear opening. A connecting plate 32 is provided inside the main body 31 near the opening. The connecting rod 5 is a spring telescopic rod used to connect the main body 31 and the connecting plate. 32. An elastic force is applied to the connecting plate 32 to make it abut against the inner wall of the opening of the main body 31. A telescopic elastic rod 75B is fixed between the inner center of the ring body 1 71B and the connecting rod 5. A protruding layer 76B is fixed on the outer side of the ring body 1 71B. A limiting protrusion 77B is fixed on the movement trajectory of the protruding layer 76B inside the main body 31. A T-shaped extrusion rod 33 is provided through the surface of the connecting plate 32 on one side of the protruding layer 76B. An elastic element 34 is sleeved in the area of ​​the extrusion rod 33 inside the main body 31. The elastic element 34 is used to apply a pushing force towards the inside of the main body 31 to the extrusion rod 33. A protruding layer 35 is fixed on the outer side of the main body 31. A limiting protrusion 36 is fixed on the inner wall of the shell 21 on one side of the protruding layer 35.

[0034] Specifically, the elastic tie rod 75B restricts the movement direction of ring 71B and ring 73B. The elastic tie rod 75B applies an elastic pulling force to ring 71B and ring 73B, causing them to retract into the main body 31. When the flared core 3 is inserted into the flaring mold 2, the limiting protrusion 36 limits the protrusion layer 35 as it moves with the flared core 3, thus restricting the further entry of the main body 31 when the flared core 3 is inserted into the pipe to the designated position. Subsequently, the driving component 9 continues to apply a pushing force to the flared core 3, pushing the connecting plate 32 to compress the connecting rod 5 and penetrate deeper into the main body 31. During the movement, the connecting plate 32 drives the extrusion rod 33 to extrude the protrusion layer 76B, thereby pushing ring 71B towards the extrusion block. The movement of 601, in conjunction with the connecting rod 72B, applies an outward pushing force to the extrusion block 601, causing it to extend outward. When the protruding layer 76B moves to abut against the limiting protrusion 77B, the ring body 71B extends to its maximum extent. Under the restriction of the limiting protrusion 77B, as the connecting plate 32 continues to move, the compression elastic element 34 and the extrusion rod 33 also move outward from the main body 31, fixing the position of the ring body 71B. During the subsequent movement of the connecting plate 32, the ring body 73B is pushed towards the extrusion block 602, causing the ring body 73B to cooperate with the connecting rod 74B to push the extrusion block 602 outward. Thus, the ring body 71B and the ring body 73B move outward successively to form an annular protruding extruded tube.

[0035] Example 5, please refer to the appendix. Figure 10 -Appendix Figure 12 Regarding the heating or expansion method of the pipe as described in the patent cited in the background art, this embodiment improves the heating and expansion method of the pipe. A fixed platform 10 is provided on the outer side of the driving component 9, and both the driving component 9 and the electric push cylinder 22 are fixedly connected to the fixed platform 10. An electric push cylinder 11 is fixedly provided on one side of the fixed platform 10. The heating assembly 12 is provided on the driving end of the electric push cylinder 11. The heating assembly 12 includes a fixed panel 121 fixedly connected to the driving end of the electric push cylinder 11. Two sets of heating cylinders 122 with different diameters are concentrically arranged on the side wall of the fixed panel 121, wherein the inner diameter of the larger heating cylinder 122 is the same as the outer diameter of the pipe, and the smaller one... The outer diameter of the heating cylinder 122 is the same as the inner diameter of the pipe. A connecting post 123 is fixed at the center of the fixed panel 121. A support cylinder 14 and an electromagnet 13 are respectively provided at the front end of the connecting post 123 and the flared core 3. The electromagnet 13 is embedded and fixed at the front end of the connecting post 123 and the flared core 3. The two support cylinders 14 are made of ferromagnetic material, and the side walls of the two support cylinders 14 are provided with annular grooves 15. Annular bodies 16 are inserted into the two annular grooves 15. The two annular bodies 16 are fixedly connected to the connecting post 123 and the flared core 3 respectively. An electric push cylinder 17 is embedded and fixed at the front end of the connecting post 123. The outer diameter of the support cylinder 14 is the same as the inner diameter of the pipe.

[0036] Specifically, through the operation of electromagnet 13 and the insertion and engagement of ring body 16 and annular groove 15, support cylinder 14 is fixed to the front side of heating assembly 12. The pipe is first conveyed to one side of heating assembly 12. Electric pusher cylinder 11 extends and pushes support cylinder 14 and heating assembly 12 into the pipe in sequence. Two sets of heating cylinders 122 heat the expanded end of the pipe. After heating, electric pusher cylinder 11 retracts, and when support cylinder 14 partially moves out of the pipe, electromagnet 13 stops operating. Then, electric pusher cylinder 17 extends and pushes support cylinder 14 in the reverse direction, causing ring body 16 to separate from annular groove 15, allowing support cylinder 14 to remain inside the pipe. The unheated section inside the pipe then heats the support cylinder 14. 4. Providing support and supporting the heating section of the pipe through the support tube can effectively prevent the pipe from shrinking radially during the heating process. Subsequently, the pipe is moved to the flaring mold 2 by the conveying device 1 for expansion. When the flaring core 3 is inserted into the pipe, the electromagnet 13 at its front end cooperates with the ring body 16 to attract and fix the support cylinder 14 inside the pipe so that the support cylinder 14 can be brought out synchronously when the flaring core 3 is withdrawn. By separating the heating and expansion process of the pipe and supporting the heated pipe with the support cylinder 14 to prevent the pipe from shrinking radially during the conveying process, one pipe can be flared and wait for cooling while another pipe is heated, thus saving heating efficiency compared with the prior art.

[0037] Please see the appendix Figure 10 A conveying assembly 18 is provided on the fixed platform 10. The conveying assembly 18 includes an electric slide table 181, which is fixed on the fixed platform 10. An electric push cylinder 182 is fixed above the slider of the electric slide table 181. A bearing seat 183 is fixed at the drive end of the electric push cylinder 182, and a bearing groove is provided on the top of the bearing seat 183.

[0038] Specifically, when the flared chip drives the support cylinder 14 to retract above the carrier seat 183, the electric pusher cylinder 182 extends, causing the carrier seat 183 to rise, thus moving the support cylinder 14 into the carrier groove. The flared chip then continues to retract, causing the support cylinder 14 to remain in the carrier groove. The electric slide 181 then transports the support cylinder 14 to the heating assembly 12, allowing the heating assembly 12 to again adhere and fix the support cylinder 14, thus enabling the reuse of the support cylinder 14. The support cylinder 14 is configured in three groups: one group is located at the front end of the heating assembly 12, and another group... Located at the front end of the flared chip, one set is located in the conveying component 18, and can be recycled through three sets of support cylinders 14; the present invention realizes the closed-loop automatic turnover and reuse of support cylinders 14, and the support cylinders 14 are transferred and recycled by the conveying component 18. Only three sets of support cylinders 14 are required for uninterrupted cyclic operation, without the need for frequent disassembly and disassembly of equipment and tooling, which greatly reduces the input of spare parts and consumables and the time spent on manual replacement of parts; the turnover of support cylinders 14 is carried out synchronously with the pipe heating and flaring process, without occupying the production cycle, further improving the continuous operation rate of equipment and the processing efficiency of the production line.

[0039] An expansion method for manufacturing PVC-O pipes, the method comprising: S1. The pipe is conveyed to the heating station by the conveying device 1. The electric push cylinder 3 11 drives the heating component 12 to move forward. The support cylinder 14 is fixed by the electromagnet 13. The double-layer heating cylinder 122 of the heating component 12 covers the inner and outer walls of the flared end of the pipe and heats the end of the pipe to a softened state. S2, the heating component 12 retracts, the electric push cylinder 17 pushes the support cylinder 14 to separate from the connecting column 123 and remain inside the pipe. The support cylinder 14 limits the pipe to prevent it from shrinking due to heat. Then the pipe is sent into the inner cavity of the flared mold 2, which is composed of the shell 21 and locked and closed by the electric push cylinder 22. S3, the driving component 9 pushes the flared core 3 into the inner cavity of the pipe, and the pushing component 7 on the connecting rod 5 drives the extrusion block 601 and extrusion block 602 to expand radially outward, supporting the sealing film 4 to bulge out locally, extruding and softening the pipe wall and pressing it into the forming groove of the flared mold 2, forming an integral sealing groove and positioning boss. S4. After cooling, extrusion block 1 (601) and extrusion block 2 (602) are retracted into the cavity of the flared core 3. The electromagnet 13 at the front end of the flared core 3 attracts the support cylinder 14 and pulls out the tube along with the core. The electric push cylinder 4 (22) controls the shell 21 to open the mold and discharge the material.

[0040] Those skilled in the art can connect all electrical components and their compatible power supplies in this case via wires. Appropriate controllers should be selected according to the actual situation to meet control requirements. The specific connection and control sequence should refer to the above-described specific embodiments. The electrical connection is completed by the sequential operation of each electrical component. The detailed connection methods are well-known technologies in the art. The above mainly introduces the working principle and process, and will not describe the electrical control.

[0041] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An expansion device for manufacturing PVC-O pipes, comprising a conveying device (1) for conveying the pipe, a flaring mold (2), a conical flaring core (3), a driving component (9) for pushing the flaring core (3) into the flaring mold (2), and a heating assembly (12) for heating the pipe, wherein the driving end of the driving component (9) is fixedly connected to the flaring core (3), characterized in that: The flared core (3) has an internal cavity, and the outer surface of the flared core (3) has an annular notch. A deformable sealing membrane (4) is fixed at the notch. Connecting rods (5) are fixed on both sides of the cavity. An extrusion assembly (6) is provided on the surface of the connecting rod (5) corresponding to the notch. The extrusion assembly (6) includes several extrusion blocks 1 (601) and extrusion blocks 2 (602) that are respectively distributed in an annular shape along the circumference, and the extrusion blocks 1 (601) and extrusion blocks 2 (602) are arranged alternately. The connecting rod (5) is provided with a pushing component (7). The pushing component (7) is used to drive the extrusion block one (601) and extrusion block two (602) to extend radially outward to support the sealing film (4) to form an annular protrusion, or to retract radially inward to be housed in the cavity. The flaring mold (2) includes two housings (21) and electric push cylinder four (22) is provided on the outer side of each of the two housings (21). The driving end of the electric push cylinder four (22) is fixedly connected to the adjacent housing (21).

2. The expansion device for manufacturing PVC-O pipes according to claim 1, characterized in that: The pushing assembly (7) includes several electric push cylinders 1 (71A) and 2 (72A) that are respectively distributed in a circumferential ring and fixed on the connecting rod (5). The driving end of electric push cylinder 1 (71A) is fixedly connected to extrusion block 1 (601), and the driving end of electric push cylinder 2 (72A) is fixedly connected to extrusion block 2 (602).

3. The expansion device for manufacturing PVC-O pipes according to claim 1, characterized in that: The pushing assembly (7) includes a ring body one (71B) and a ring body two (73B) sleeved on the connecting rod (5). The ring body one (71B) is hinged to the extrusion block one (601) and the ring body two (73B) is hinged to the extrusion block two (602) and the extrusion block two (602) and the connecting rod two (74B).

4. The expansion device for manufacturing PVC-O pipes according to claim 3, characterized in that: The first ring (71B) and the second ring (73B) are respectively provided with two sets located on both sides of the center point of the first extrusion block (601) or the second extrusion block (602). An adjustment component (8) is installed on the connecting rod (5). The adjustment component (8) includes a slot opened on the connecting rod (5) and mounting slots (806) opened on the upper and lower sides of the inner wall of the first ring (71B) and the second ring (73B). Two sets of sliding blocks (802) are slidably connected inside the slot, and a double-acting screw (803) is threaded at the center of the two sliding blocks (802). A motor (804) is fixed on one side of the slot. The driving end of the motor (804) is fixed to one end of the double-acting screw (803). The sliding block (802) is fixedly connected to a micro electric cylinder (805) embedded in its upper and lower sides respectively. A locking block (807) is slidably disposed inside the mounting groove (806). An elastic element (808) is fixed between the locking block (807) and the mounting groove (806). The side of the locking block (807) facing the micro electric cylinder (805) is provided with a slot (809) for the driving end of the micro electric cylinder (805) to be inserted. Openings are respectively opened on the upper and lower sides of the slot. The width of the opening is smaller than the diameter of the locking block (807) and larger than the diameter of the driving end of the micro electric cylinder (805). Several limiting grooves (810) for the locking block (807) to be inserted are provided on the surface of the opening.

5. An expansion device for manufacturing PVC-O pipes according to claim 3, characterized in that: The flared core (3) includes a main body (31) with a rear opening. A connecting plate (32) is provided inside the main body (31) near the opening. The connecting rod (5) is a spring telescopic rod used to connect the main body (31) and the connecting plate (32) and apply elastic force to the connecting plate (32) so that it abuts against the inner wall of the opening of the main body (31). A telescopic elastic rod (75B) is fixed between the first ring (71B) and the second ring (73B) and the connecting rod (5). A protruding layer (76B) is fixed on the outer side of the first ring (71B). A limiting protrusion (77B) is fixed on the movement trajectory of the protruding layer (76B) inside the main body (31). A T-shaped extrusion rod (33) is provided through the surface of the connecting plate (32) on one side corresponding to the protruding layer (76B). An elastic element (34) is sleeved in the area of ​​the extrusion rod (33) inside the main body (31).

6. An expansion device for manufacturing PVC-O pipes according to claim 5, characterized in that: The outer side of the main body (31) is provided with a second protrusion (35), and the inner wall of the shell (21) is provided with a second limiting protrusion (36) on one side corresponding to the second protrusion (35).

7. An expansion device for manufacturing PVC-O pipes according to claim 1, characterized in that: A fixed platform (10) is provided on the outside of the driving component (9), and the driving component (9) and the electric push cylinder four (22) are both fixedly connected to the fixed platform (10). An electric push cylinder three (11) is fixedly provided on one side of the fixed platform (10). The heating component (12) is provided on the driving end of the electric push cylinder three (11). The heating component (12) includes a fixed panel (121) fixedly connected to the driving end of the electric push cylinder three (11). Two sets of heating cylinders (122) with different diameters are concentrically arranged on the side wall of the fixed panel (121).

8. An expansion device for manufacturing PVC-O pipes according to claim 7, characterized in that: A connecting post (123) is fixed at the center of the fixed panel (121). A support cylinder (14) and an electromagnet (13) are respectively provided at the front end of the connecting post (123) and the flared core (3). The electromagnet (13) is embedded and fixed at the front end of the connecting post (123) and the flared core (3). The two support cylinders (14) are made of ferromagnetic material, and the side walls of the two support cylinders (14) are provided with annular grooves (15). A ring body three (16) is inserted into the two annular grooves (15). The two ring bodies three (16) are fixedly connected to the connecting post (123) and the flared core (3) respectively. An electric push cylinder five (17) is embedded and fixed at the front end of the connecting post (123).

9. An expansion device for manufacturing PVC-O pipes according to claim 8, characterized in that: The fixed platform (10) is provided with a conveying assembly (18), which includes an electric slide (181). The electric slide (181) is fixed on the fixed platform (10). An electric push cylinder six (182) is fixed above the slider of the electric slide (181). A bearing seat (183) is fixed at the drive end of the electric push cylinder six (182), and a bearing groove is opened on the top of the bearing seat (183).

10. An expansion method for manufacturing PVC-O pipes, characterized in that, An expansion apparatus for manufacturing PVC-O pipes according to any one of claims 1-9, the method comprising: S1. The pipe is transported to the heating station by the conveying device (1). The electric push cylinder three (11) drives the heating component (12) to move forward. The support cylinder (14) is fixed by the electromagnet (13). The double-layer heating cylinder (122) of the heating component (12) covers the inner and outer walls of the flared end of the pipe and heats the end of the pipe to a softened state. S2, the heating component (12) retracts, the electric push cylinder five (17) pushes the support cylinder (14) to separate from the connecting column (123) and remain inside the pipe. The support cylinder (14) limits the pipe to prevent it from shrinking due to heat. Then the pipe is sent into the inner cavity of the flared mold (2) which is composed of the shell (21) and locked and closed by the electric push cylinder four (22). S3, the driving component (9) pushes the flared core (3) into the inner cavity of the pipe, and the pushing component (7) on the connecting rod (5) drives the extrusion block one (601) and extrusion block two (602) to expand radially outward, supporting the sealing film (4) to bulge out locally, and extruding and softening the pipe wall to press into the flared mold (2) forming groove, forming an integral sealing groove and positioning boss; S4. After cooling, the extrusion block one (601) and extrusion block two (602) are brought inward and put into the cavity of the flared core (3). The electromagnet (13) at the front end of the flared core (3) adsorbs the support cylinder (14) and pulls out the tube along with the core. The electric push cylinder four (22) controls the shell (21) to open the mold and discharge the material.

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