Plastic pipe bending forming device and bending forming method thereof

Abstract

The application belongs to the technical field of pipe processing, and relates to a plastic pipe bending forming device and a bending forming method thereof. The bending forming device comprises a rack, a hydraulic drive mechanism, a female die support plate, a male die support plate and forming inserts. The hydraulic drive mechanism can drive the male die support plate to approach or move away from the female die support plate. The opposite surfaces of the female die support plate and the male die support plate are respectively an inner concave arc surface and an outer convex arc surface. The arc radius of the inner concave arc surface is the same as that of the outer convex arc surface. A plurality of forming inserts are detachably connected on the inner concave arc surface and the outer convex arc surface along the circular arc extension direction. A semicircular groove is arranged on the forming insert. The hydraulic drive mechanism can drive the male die support plate to approach the female die support plate, so that the semicircular grooves on both sides wrap the plastic pipe together to bend the plastic pipe. The part of the rack which is in contact with the plastic pipe is provided with a detachably connected heightening pad plate. The application has the advantages of simple structure, low manufacturing cost, strong universality, convenient operation, high efficiency and the like.

Description

Technical Field

[0001] This invention belongs to the field of pipe processing technology, and specifically relates to a plastic pipe bending and forming device and a bending and forming method. Background Technology

[0002] In the construction of municipal water supply and drainage and industrial fluid transportation pipeline networks, the on-site bending and forming of large-diameter thermoplastic pipes (such as PE160 pipes) is a critical process. Depending on the geometric accuracy requirements of the engineering assembly, the bending operation of such pipes typically requires precise control of the bending diameter (e.g., 1.5 meters) and the retention of a specific length of straight pipe section (e.g., 0.5 meters) to ensure the fluid sealing and connection strength of the pipeline system.

[0003] However, existing technologies for bending plastic pipes to meet the aforementioned specific geometric precision requirements still suffer from the following significant technical drawbacks: First, during the bending process, due to the softness of the plastic pipe material and the lack of effective rigid support, problems such as pipe wall collapse, wrinkling, and cross-sectional flattening easily occur, severely affecting the ring stiffness and performance of the pipe. Second, existing molds are mostly integral structures, only suitable for single-specification pipes, resulting in poor versatility. When changing to pipes of different diameters, the entire mold must be replaced, leading to high costs and low efficiency. Third, some bending methods require filling the pipe with sand or adding springs for auxiliary support, which is cumbersome, inefficient, and makes it difficult to achieve precise bending of a 1.5-meter median diameter. Fourth, the mold-changing structure of existing bending devices is complex, making it inconvenient for workshop self-manufacturing and maintenance. For small and medium-sized enterprises and individual processors, the equipment investment cost is high, making it difficult to meet the processing needs of small batches and multiple specifications. Summary of the Invention

[0004] In view of this, the purpose of this invention is to address the problems of easy deformation of plastic pipes during bending, poor mold versatility, cumbersome operation, and high cost in the prior art, and to provide a plastic pipe bending and forming device and a bending and forming method thereof.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A plastic pipe bending and forming device includes a frame, a hydraulic drive mechanism, a concave die support plate, a convex die support plate, and forming inserts. The hydraulic drive mechanism and the concave die support plate are fixedly mounted on the frame, while the convex die support plate is horizontally slidably mounted on the frame. The hydraulic drive mechanism is connected to the convex die support plate and can drive the convex die support plate to approach or move away from the concave die support plate along a straight line. The opposing surfaces of the concave die support plate and the convex die support plate are an inner concave arc surface and an outer convex arc surface, respectively. The radius of the arc of the inner concave arc surface is the same as that of the outer convex arc surface. Multiple forming inserts are detachably connected to both the inner concave arc surface and the outer convex arc surface along the arc extension direction. The forming inserts are provided with semi-circular grooves. The hydraulic drive mechanism can drive the convex die support plate to approach the concave die support plate, so that the semi-circular grooves on both sides together wrap around the plastic pipe and bend it. A detachably connected raising pad is provided on the part of the frame that contacts the plastic pipe.

[0007] To better realize the present invention, the above structure is further optimized by providing a limiting plate on the frame, with one end of the plastic tube abutting against the side of the limiting plate.

[0008] To better realize the present invention, the above structure is further optimized, and the hydraulic drive mechanism is a hydraulic cylinder.

[0009] To better realize the present invention, the above structure is further optimized. The piston rod of the hydraulic cylinder is fixedly connected to the mounting bracket, the punch support plate is fixedly mounted on the mounting bracket, and a sliding guide rod is provided between the mounting bracket and the machine frame.

[0010] To better realize the present invention, the above structure is further optimized. The plastic tube bending and forming device also includes an anti-detachment pin. A connecting column is provided on the forming insert. Both the concave die support plate and the convex die support plate are provided with connecting holes. The forming insert is slidably connected to the connecting column by inserting it into the connecting hole. A pin hole is provided on the side of the connecting column. The anti-detachment pin is inserted into the pin hole from the side to lock it.

[0011] To better realize the present invention, the above structure is further optimized by fixing a mounting base on the molded insert and fixing the connecting column on the mounting base.

[0012] To better realize the present invention, the above structure is further optimized, and the inner diameter of the semi-circular groove is 2-5 mm larger than the outer diameter of the plastic tube.

[0013] A method for bending and forming a plastic tube includes the following steps: S1. Heat and soften the part of the plastic pipe to be bent; S2. Place the softened plastic tube on the raising pad, with one end of the plastic tube against the side of the limiting plate. S3. Start the hydraulic drive mechanism to drive the punch support plate close to the die support plate, so that the semi-circular grooves on both sides together wrap the plastic tube, maintain the pressure for the specified time, and complete the bending and forming. S4. The hydraulic drive mechanism resets, and the bent plastic pipe is removed.

[0014] To better realize the present invention, the above structure is further optimized, and the heating and softening temperature is 100-130℃.

[0015] To better realize the present invention, the above structure is further optimized, and the specified time is 3-5 minutes.

[0016] Compared with the prior art, the present invention has the following advantages: The plastic pipe bending and forming device and its bending and forming method provided by this invention form a fully enclosed rigid support for the plastic pipe through the semi-circular grooves on both sides. No sand filling or springs are needed during the bending process, effectively avoiding defects such as pipe collapse, wrinkling, and cross-sectional flattening, resulting in excellent forming quality. It is highly versatile, using a detachable connection to replace forming inserts of different specifications and sizes. One bending and forming device can adapt to various specifications of plastic pipes such as PE160, PE90, and PE63 without requiring a complete mold replacement. The structure is simple, and the manufacturing cost is low. The core forming insert can be made by cutting steel pipes, making it suitable for small and medium-sized enterprises and individual processors to manufacture in their own workshops. Operation is convenient, the structural design is reasonable, the bending process is simple, and no extra auxiliary tools are required, significantly improving processing efficiency. Attached Figure Description

[0017] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of the plastic pipe bending and forming device of the present invention; Figure 2 This is a schematic diagram of the connection structure between the concave mold support plate and the convex mold support plate in this invention; Figure 3 This is a schematic diagram of the structure in this invention where the molded insert uses anti-detachment pins to achieve a detachable connection.

[0019] In the picture: 1. Frame; 2. Hydraulic drive mechanism; 3. Die support plate; 4. Punch support plate; 5. Molding insert; 501. Semi-circular groove; 6. Heightening pad; 7. Limiting plate; 8. Mounting bracket; 9. Sliding guide rod; 10. Anti-detachment pin; 11. Connecting column; 12. Connecting hole; 13. Mounting base; 100. Plastic pipe. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0021] In the description of this invention, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] Example 1: Please refer to Figure 1 and Figure 2 The plastic pipe bending and forming device provided by the present invention includes a frame 1, a hydraulic drive mechanism 2, a concave die support plate 3, a convex die support plate 4, and a forming insert 5. It has a simple structure and low manufacturing cost. The core forming insert can be made by cutting steel pipes, and the manufacturing cost is only 1 / 10 of that of traditional molds. It is suitable for small and medium-sized enterprises and individual processors to make their own. It is easy to operate, has a reasonable structural design, and a simple bending process. It does not require any extra auxiliary tools and can greatly improve processing efficiency.

[0024] The hydraulic drive mechanism 2 uses a hydraulic cylinder to provide driving force. The hydraulic drive mechanism 2 and the die support plate 3 are fixedly mounted on the frame 1, while the punch support plate 4 is horizontally slidably mounted on the frame 1. The hydraulic drive mechanism 2 connects to the punch support plate 4 and can drive the punch support plate 4 to approach or move away from the die support plate 3 in a straight line. The opposing surfaces of the die support plate 3 and the punch support plate 4 are an inner concave arc surface and an outer convex arc surface, respectively. The plastic pipe 100 to be processed is placed on the frame 1 between the inner concave arc surface and the outer convex arc surface. The radius of the inner concave arc surface and the radius of the outer convex arc surface are the same, and their arc lengths are also the same. This ensures that the arc shapes of the two arc surfaces are identical, and that their lengths are also identical, allowing the two arc surfaces to fit together and thus ensuring the accuracy of mold closing. Furthermore, multiple forming inserts 5 are detachably connected to both the concave and convex arc surfaces along the arc extension direction. The forming inserts 5 on both arc surfaces are evenly spaced along the arc extension direction, making the pressure applied to the plastic pipe 100 more uniform and improving product quality. Each forming insert 5 has a semi-circular groove 501, and two semi-circular grooves 501 can be combined to form a complete circle. In this embodiment, the forming insert 5 is installed onto the concave and convex arc surfaces using a detachable insertion-interference fit. Alternatively, other detachable connection methods such as snap-fit ​​or threaded connection can also be used. Because the forming insert 5 uses a detachable connection method, it is highly versatile. Different specifications and sizes of forming inserts 5 can be replaced using this detachable connection method. One bending and forming device can be adapted to various specifications of plastic pipes such as PE160, PE90, and PE63 without requiring a complete mold replacement, thus broadening its applicability.

[0025] The semi-circular grooves 501 on both sides form a fully enclosed rigid support for the plastic pipe 100. No sand or springs are needed during bending, which effectively avoids defects such as collapse, wrinkling, and flattening of the pipe, resulting in excellent forming quality and strong versatility.

[0026] During the preparation of the molding insert 5, a steel pipe with an inner diameter 2-5 mm larger than the outer diameter of the plastic pipe 100 is selected. It is radially cut into several short cylinders of the same size, and then the short cylinders are cut into two semi-circular rings along the axial center. The inner diameter of the semi-circular rings is the inner diameter of the semi-circular groove 501. The inner diameter of the semi-circular groove 501 is 2-5 mm larger than the outer diameter of the plastic pipe 100. This gap provides a buffer space for the thermal expansion of the plastic pipe 100 during heating, preventing deformation or jamming due to thermal expansion. It also ensures smooth demolding of the molded plastic pipe 100, effectively improving production efficiency. Simultaneously, the covering structure of the semi-circular groove 501 can still stably restrict the radial displacement of the pipe, preventing shaking during processing and ensuring processing accuracy and product quality.

[0027] The hydraulic drive mechanism 2 can drive the punch support plate 4 to approach the die support plate 3, so that the semi-circular grooves 501 on both sides together wrap around the plastic tube 100 and bend it. A detachable lifting pad 6 is provided on the part of the frame 1 that contacts the plastic tube 100. The lifting pads 6 are designed as a set, with different thicknesses to fit different sizes of molding inserts 5. In this embodiment, the lifting pad 6 is snap-fitted onto the frame 1. When a molding insert 5 of a different size is replaced, in order to ensure that the plastic tube 100 remains centered in the semi-circular grooves 501 on both sides, it is necessary to replace it with a lifting pad 6 of the corresponding thickness for support. For example, if a PE160 plastic pipe is replaced with a PE90 plastic pipe, not only does the molding insert 5 need to be replaced with a smaller size that matches the PE90 plastic pipe, but it also needs to be replaced with a thicker raising pad 6 to compensate for the height of the PE90 plastic pipe, so that it is in the center of the semi-circular grooves 501 on both sides. When the semi-circular grooves 501 on both sides are closed, they can smoothly wrap the PE90 plastic pipe.

[0028] A limiting plate 7 is installed on the side of the frame 1. The side of the limiting plate is polished and made of stainless steel, with a smooth and flat surface, which can effectively prevent scratches on the surface of the plastic tube during operation. During processing, one end of the plastic tube 100 will be tightly pressed against the smooth side of the limiting plate 7. The limiting plate 7 accurately positions the plastic tube 100, thereby ensuring the accuracy of the tube's position during bending and making the bending process more precise and reliable.

[0029] The punch support plate 4 is fixedly connected to the piston rod of the hydraulic cylinder through a sturdy mounting bracket 8. Multiple parallel sliding guide rods 9 are also provided between the mounting bracket 8 and the frame 1. These guide rods play a guiding and supporting role, so that the punch support plate 4 can move smoothly along the preset trajectory of the sliding guide rods 9 under hydraulic drive, effectively preventing swaying or shaking, thereby significantly improving the stability of the entire device during operation and the positional accuracy of bending processing.

[0030] The main structural frame of the entire bending and forming device is constructed from high-strength steel plates and thick-walled steel pipes. The overall structural design is robust and rational, possessing excellent durability and load-bearing capacity, capable of withstanding the large thrust applied by the hydraulic drive mechanism 2 without easily deforming. Furthermore, individual forming inserts 5 can be independently disassembled and replaced after long-term wear, without replacing the entire mold assembly. This design not only facilitates maintenance but also significantly extends the overall service life of the device, reducing long-term maintenance costs. In addition, the device can automatically increase or decrease the number of forming inserts 5 according to the bending length. The part enclosed by the semi-circular groove 501 in the middle is the bending section, and the two sides of the bending section are the straight pipe sections.

[0031] Working principle: Before processing, according to the diameter of the plastic pipe 100, select the forming insert 5 with a corresponding semi-circular groove 501 and install it on the concave mold support plate 3 and the convex mold support plate 4 respectively. Then, according to the placement height requirements of the plastic pipe 100, adjust and install the corresponding thickness of the lifting pad 6. During processing, place the preheated and softened plastic pipe 100 on the lifting pad 6 to complete the positioning. Then, start the hydraulic drive mechanism 2. The hydraulic cylinder extends and pushes the convex mold support plate 4 along the sliding guide rod 9 towards the concave mold support plate 3. The forming inserts 5 on both sides gradually close, and the semi-circular grooves 501 on both sides together wrap around the plastic pipe 100 for bending and forming. Finally, the hydraulic cylinder resets and drives the convex mold support plate 4 to retract, and the bent plastic pipe can be taken out. If it is necessary to process plastic pipes of different diameters, simply remove the original forming insert 5, replace it with a forming insert 5 of the corresponding specification and a lifting pad 6 of the corresponding thickness, and start processing again. The adjustment is convenient and quick.

[0032] Example 2: The main structural difference between this embodiment and Embodiment 1 is that the forming insert 5 adopts a pin-type detachable connection scheme. Specifically, the bending forming device adds an anti-detachment pin 10, and a mounting base 13 is fixedly installed on the forming insert 5. A connecting post 11 is firmly installed on the mounting base 13. The mounting base 13, as the key connection medium between the forming insert 5 and the connecting post 11, has the dual core functions of size compensation and benchmark unification. Since this device adopts a universal and unchanging structural design for the concave mold support plate 3 and the convex mold support plate 4, when facing plastic pipes 100 of different specifications and models, there are also semi-circular grooves 501 with different radii and wall thicknesses. This leads to objective differences in the back contour dimensions and radial material thickness of the forming inserts 5 of different specifications. The mounting base 13, through preset standardized dimensions, compensates for the deviation in radial dimensions of the forming inserts 5 of different specifications. Different specifications of forming inserts 5 correspond to mounting bases 13 of different lengths, which is similar to the function of the heightening pad 6.

[0033] Mounting base 13 can forcibly constrain and ensure the installation position of connecting column 11, keeping its position constant after installation. This ensures that after all different specifications of forming inserts 5 are installed on the universal die support plate 3 and punch support plate 4, the cross-section of the semi-circular groove 501 on its inner side is always precisely in the same preset center plane. This design eliminates the center deviation caused by changing insert specifications, eliminating the need to compensate by controlling the extension and retraction length of the hydraulic cylinder. It is more convenient to operate, ensuring strict consistency of the forming center distance between die support plate 3 and punch support plate 4, as well as the accuracy of the arc alignment of the inserts on both sides. This enables the same set of frame 1 and support plate to adapt to bending forming operations with multiple pipe diameters and multiple bending radii, greatly improving mold closing accuracy and forming quality.

[0034] Corresponding to the connecting post 11, connecting holes 12 are pre-machined on both the die support plate 3 and the punch support plate 4. During assembly, the connecting post 11 on the forming insert 5 is aligned and inserted into the connecting hole 12 on the support plate to achieve a sliding fit connection. To ensure a firm connection and prevent loosening, a pin hole is specially opened on the side wall of the connecting post 11. After assembly, the anti-loosening pin 10 is passed through the side of the support plate and inserted into the pin hole, thereby locking the connecting post 11 in the support plate. This structure effectively restricts the axial degree of freedom of the forming insert 5, preventing it from accidentally loosening or falling off under equipment vibration, and ensuring the stability and safety of the mold assembly connection. At the same time, it forms a reliable circumferential limit for the forming insert 5. Utilizing the geometric self-locking characteristics of the arc surface and the shear resistance of the pin, it effectively resists the lateral extrusion force and torque generated during bending processing, preventing the forming insert 5 from rotating or twisting around its own axis, and ensuring that the insert maintains angular stability under stress. When it is necessary to disassemble and replace the molding insert 5, first pull the anti-detachment pin 10 out of the pin hole to release the locking of the connecting post 11; then, the connecting post 11 can be easily pulled out of the connecting hole 12, thereby removing the original molding insert 5. Next, simply select a new insert of the corresponding size and reassemble it to quickly complete the mold replacement operation. The entire mold replacement process is clear and simple to operate, significantly improving work efficiency and making maintenance and replacement more convenient and efficient.

[0035] In this embodiment, the radius of the formed curved surface of the plastic pipe 100 is calculated by superimposing the dimensions of each component. The specific dimensional chain relationship is as follows: Formula for superimposing forming radii on the die side: The sum of the radius of the concave arc surface of the die support plate 3, the length of the mounting base 13, and the radial wall thickness of the forming insert 5 is equal to the outer arc radius of the plastic pipe 100 after bending.

[0036] Formula for superimposing forming radii on the punch side: The radius of the outer convex arc surface of the punch support plate 4, plus the length of the mounting base 13, plus the radial wall thickness of the forming insert 5, are equal to the inner arc radius of the plastic pipe 100 after bending.

[0037] By adjusting the length of the mounting base 13 or the wall thickness of the forming insert 5, this device can accurately adapt to plastic pipes with different outer diameters while keeping the basic curvature of the concave mold support plate 3 and the convex mold support plate 4 unchanged, thus achieving multiple uses in one machine.

[0038] Taking a PE160 pipe with a mean diameter of 1.5 meters after bending as an example: Assume that the length of the mounting base 13 is 50mm and the wall thickness of the molded insert 5 is 30mm.

[0039] Die side (corresponding to the outer arc of the tube 1580mm): Target: The final forming radius should reach 1580mm.

[0040] Component stacking: Mounting base (50mm) + insert wall thickness (30mm) = 80mm.

[0041] Therefore, the basic radius of the concave mold support plate 3 needs to be processed to be: 1580-80=1500mm.

[0042] Verification: 1500 (plate) + 50 (base) + 30 (piece) = 1580mm (perfectly fits the outer wall of the pipe).

[0043] Punch side (corresponding to the inner arc of the tube, 1420mm): Target: The final forming radius should reach 1420mm.

[0044] Component stacking: Mounting base (50mm) + insert wall thickness (30mm) = 80mm.

[0045] Therefore, the basic radius of the punch support plate 4 needs to be machined to be: 1420-80=1340mm.

[0046] Verification: 1340 (plate) + 50 (base) + 30 (piece) = 1420mm (perfectly fits the inner wall of the pipe).

[0047] Example 3: This invention also provides a method for using the plastic tube bending and forming device, the specific operation steps of which are as follows: Before the bending process begins, the operator needs to select and prepare matching forming inserts 5 according to the specific diameter and specifications of the plastic pipe 100 to be processed. These selected forming inserts 5 are then accurately installed into the designated positions on the concave die support plate 3 and the convex die support plate 4 of the device. Furthermore, based on the required placement height of the plastic pipe 100 during processing, precise height adjustments are made by adding or replacing height-adjusting shims 6 of appropriate thickness. Only after all these preliminary preparations are completed and confirmed to be correct can the subsequent bending operation begin.

[0048] S1. First, select the plastic pipe 100 that needs to be bent and carefully clean its outer wall to ensure that there is no dirt or impurities on the surface. Next, smoothly feed the cleaned plastic pipe 100 into the heating equipment and evenly heat the specific part that is to be bent, so that the temperature of the part gradually rises to a predetermined range of 100-130 degrees Celsius until the plastic material is fully softened and reaches a state suitable for plastic deformation.

[0049] S2. Subsequently, the heated and softened plastic pipe 100 is removed from the heating equipment and placed on the upper surface of the height-adjusted riser plate 6. During this process, one end of the plastic pipe 100 must be tightly pressed against the vertical side of the limiting plate 7 on the side of the device. The limiting plate 7 is used to accurately position the pipe in the horizontal direction to prevent it from shifting during subsequent processing.

[0050] S3. After positioning is completed, the hydraulic drive mechanism 2 is activated to drive the punch support plate 4 to move smoothly towards the fixed die support plate 3, causing the two support plates to gradually close. During this mold closing process, the pushing speed of the punch support plate 4 needs to be controlled at 5mm / s. As the support plates approach, the semi-circular grooves 501 installed on the inner sides of the forming inserts 5 on both sides begin to wrap around and contact the plastic pipe 100. Under continuous and uniform pressure, the plastic pipe 100 gradually undergoes plastic bending deformation along the specific arc of the inner concave arc surface and the outer convex arc surface until its bending angle reaches the preset target value of 90°. After reaching the target angle, the current pressure state needs to be maintained for about 3 to 5 minutes to complete the final bending and shaping process, ensuring the shape stability and structural strength of the bent part of the pipe.

[0051] S4. After the bending and pressure holding processes are completed, the hydraulic drive mechanism 2 is operated in reverse to drive the punch support plate 4 back to its initial open position, preparing the device for the next bending operation. Then, the bent plastic pipe is removed. The final finished pipe has good cross-sectional roundness at the bent part, no obvious defects such as collapse or wrinkling, and the bending angle is accurate, meeting the predetermined process quality requirements.

[0052] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A plastic tube bending and forming device, characterized in that: The assembly includes a frame (1), a hydraulic drive mechanism (2), a die support plate (3), a punch support plate (4), and a forming insert (5). The hydraulic drive mechanism (2) and the die support plate (3) are fixedly mounted on the frame (1). The punch support plate (4) is horizontally slidably mounted on the frame (1). The hydraulic drive mechanism (2) is connected to the punch support plate (4) and can drive the punch support plate (4) to approach or move away from the die support plate (3) in a straight line. The opposing surfaces of the die support plate (3) and the punch support plate (4) are respectively an inner concave arc surface and an outer convex arc surface. The concave arc surface has the same radius as the convex arc surface. Both the concave arc surface and the convex arc surface are detachably connected with multiple forming inserts (5) along the arc extension direction. The forming inserts (5) are provided with semi-circular grooves (501). The hydraulic drive mechanism (2) can drive the punch support plate (4) to approach the die support plate (3), so that the semi-circular grooves (501) on both sides together wrap the plastic pipe (100) and bend it. The part of the frame (1) that contacts the plastic pipe (100) is provided with a detachably connected raising pad (6).

2. The plastic tube bending and forming device according to claim 1, characterized in that: A limiting plate (7) is provided on the frame (1), and one end of the plastic pipe (100) abuts against the side of the limiting plate (7).

3. The plastic tube bending and forming device according to claim 1, characterized in that: The hydraulic drive mechanism (2) is a hydraulic cylinder.

4. The plastic tube bending and forming device according to claim 3, characterized in that: The piston rod of the hydraulic cylinder is fixedly connected to the mounting bracket (8), the punch support plate (4) is fixedly mounted on the mounting bracket (8), and a sliding guide rod (9) is provided between the mounting bracket (8) and the frame (1).

5. The plastic tube bending and forming device according to claim 1, characterized in that: The plastic tube bending and forming device also includes an anti-detachment pin (10). A connecting post (11) is provided on the forming insert (5). A connecting hole (12) is provided on both the concave mold support plate (3) and the convex mold support plate (4). The forming insert (5) is slidably connected to the connecting hole (12) by inserting it into the connecting post (11). A pin hole is provided on the side of the connecting post (11). The anti-detachment pin (10) is inserted into the pin hole from the side to lock it.

6. The plastic tube bending and forming device according to claim 5, characterized in that: A mounting base (13) is fixedly provided on the molded insert (5), and the connecting column (11) is fixedly provided on the mounting base (13).

7. The plastic tube bending and forming device according to claim 1, characterized in that: The inner diameter of the semi-circular groove (501) is 2-5 mm larger than the outer diameter of the plastic pipe (100).

8. A method for bending and forming a plastic tube based on the plastic tube bending and forming apparatus of claim 2, characterized in that, Includes the following steps: S1. Heat and soften the part of the plastic pipe (100) to be bent; S2. Place the softened plastic tube (100) on the heightening pad (6), while one end of the plastic tube (100) abuts against the side of the limiting plate (7); S3. Start the hydraulic drive mechanism (2) to drive the punch support plate (4) to approach the die support plate (3), so that the semi-circular grooves (501) on both sides together wrap the plastic pipe (100), maintain the pressure for a specified time, and complete the bending and forming. S4. The hydraulic drive mechanism (2) is reset and the bent plastic pipe (100) is removed.

9. A method for bending and forming a plastic tube according to claim 8, characterized in that: The temperature for heating and softening is 100-130℃.

10. A method for bending and forming a plastic tube according to claim 8, characterized in that: The specified time is 3-5 minutes.

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