A hot extrusion and drawing forming device and method for preparing a hollow tube with a variable cross-section

Abstract

The present invention discloses a hot extrusion forming device for producing hollow tubes with variable cross-sections, comprising a forming mechanism, a clamping mechanism, and an extrusion mechanism. The forming mechanism is provided with a billet cavity, one side of which is provided with a forming hole. The clamping mechanism is provided with a forming cavity on one side, and the clamping mechanism moves along the axial direction. The extrusion mechanism is provided with an extrusion cylinder and a perforation mandrel, the extrusion cylinder being used to extrude the billet, and the perforation mandrel being used to form the inner diameter of the hollow tube. A method for producing the hot extrusion forming device is also disclosed. The forming cavity and the forming hole are aligned and connected, the billet is placed, the perforation mandrel moves toward the billet cavity, enters the clamping mechanism, and is aligned with the ejector pin, driving the extrusion cylinder to extrude the billet. The clamping mechanism is separated from the forming mechanism, and the processing of the hollow tube is completed. The present invention provides a hot extrusion forming device and method for producing hollow tubes with variable cross-sections, which is suitable for processing hollow tubes with variable cross-sections having a large aspect ratio and ensures the coaxiality of different cross-sections.

Description

Technical Field

[0001] The invention relates to the field of pipe processing, in particular to a hot extrusion and drawing forming device and method for preparing hollow pipes with variable cross-sections. Background Art

[0002] Variable-section hollow, thin-walled, and slender tubular shafts are widely used in transmission systems in aerospace, high-end equipment, and other fields, playing a key role in transmitting power under high temperatures, high speeds, and high loads. However, due to their large aspect ratio, thin walls, and variable cross-section, the high-precision, high-performance manufacturing of these parts has become a technical challenge plaguing the industry. The traditional manufacturing process for these parts is "deep-hole drilling + heat treatment." However, due to uncontrollable factors such as excessively long drill bits or toolholders and cutting vibrations, the deep-hole drilling process can lead to dimensional deviations such as large inner holes and drilled angles, resulting in an extremely high scrap rate for parts. Furthermore, there are problems such as low material utilization and long production cycles, making it difficult to meet the growing market demand. Therefore, the use of precision plastic forming methods to replace traditional deep-hole drilling processes to produce hollow, thin-walled, and slender tubular shafts with large aspect ratios and variable cross-sections, characterized by high part performance, high material utilization, and high production efficiency, has become an inevitable trend driven by the global market.

[0003] At present, the plastic forming methods used to prepare hollow tubular shaft parts include wedge cross rolling, radial forging, extrusion, etc. However, for parts with a depth-to-diameter ratio ≥ 30 and high requirements for the inner hole shape and position dimensional accuracy, wedge cross rolling and radial forging methods will significantly affect the roundness and coaxiality of the inner hole of the parts during the parts processing process; single-pass extrusion forming will cause "excessive load on the extrusion core rod due to the excessive depth-to-diameter ratio, which will cause the core rod to bend and affect the straightness of the inner hole", and multi-pass extrusion forming requires the use of multiple extrusion dies, resulting in increased costs. At the same time, after the parts are positioned multiple times, the inner hole shape and position accuracy of the parts will also be affected, and the coaxiality of multiple positioning is prone to deviation.

[0004] At present, relevant literature has proposed plastic forming solutions for hollow tubular shaft parts with large depth-to-diameter ratio. Patent publication number CN109332410A, "A device and method for extruding a hollow thin-walled shaft with a large aspect ratio", proposes a new type of hollow thin-walled shaft extrusion device and method with a large aspect ratio. Through a simple structure, it improves the utilization rate of raw materials, shortens the production cycle, and reduces production costs. However, this structural device can only be used to manufacture hollow shafts with a constant inner diameter. Patent publication number CN105921671A, "A reverse extrusion forming method and mold for stepped hollow shaft parts", adopts a one-mold, two-process, two-pass continuous extrusion forming method to manufacture variable-section hollow shaft parts, which can speed up production, share the punch extrusion force, and improve production rhythm, but the variable-section hollow shaft parts formed are not suitable for large depth-to-diameter ratio features. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a hot extrusion forming device and method for preparing hollow tubes with variable cross-sections, which is suitable for processing hollow tubes with variable cross-sections with large aspect ratios and ensures the coaxiality of different cross-sections.

[0006] The technical solution adopted by the present invention to solve the above-mentioned problems is: a hot extrusion forming device for preparing a hollow tube with variable cross-section, comprising a forming mechanism, a clamping mechanism and an extrusion mechanism, wherein the forming mechanism is fixedly arranged, the clamping mechanism is arranged on one side of the forming mechanism, and the extrusion mechanism is arranged on the other side of the forming mechanism, the forming mechanism is provided with a billet cavity for placing the heated billet, the billet cavity is provided with a forming hole for forming the outer diameter of the hollow tube on the side close to the clamping mechanism, the clamping mechanism is provided with a forming cavity for forming the end of the hollow tube on the side close to the forming mechanism, the end outer diameter of the hollow tube is variable-diameter, and the outer diameter expands toward the end direction of the hollow tube, the clamping mechanism is movably connected along the axial direction of the forming hole, the extrusion mechanism is provided with an extrusion cylinder and a perforating core shaft, the extrusion cylinder is movably inserted in the billet cavity for extruding the billet toward the forming hole, and the perforating core shaft is movably connected on the axis of the forming hole for forming the inner diameter of the hollow tube, and the inner diameter of the hollow tube is variable-diameter.

[0007] Compared with the prior art, the advantages of the present invention are: in the production process, the outer diameter variable structure of the hollow tube is extruded by the forming cavity, and the coaxiality of the outer diameter can be guaranteed only by ensuring the coaxiality of the forming cavity structure. The coaxiality of the forming cavity structure is a mold structure, and it only needs to be processed and formed with high precision to be stably applied to the processing of concentric tubes, thereby ensuring the coaxiality of the outer diameter. The inner diameter variable structure of the hollow tube is formed by perforating the perforating mandrel, and the coaxiality of the different outer diameters of the perforating mandrel and the coaxiality of the perforating mandrel and the outer wall of the hollow tube need to be ensured to ensure the coaxiality of the inner diameter of the hollow tube. First, the perforating mandrel is also a mold structure, and can be made of high-strength material that is not easily deformed. At the same time, during the processing, a slow wire walking method with a longer cycle is used for processing. The process ensures the dimensional accuracy of the perforating mandrel and the coaxiality of different outer diameters, and then the blank is extruded in the blank cavity and moves toward the forming hole, so that the blank is compressed and gathered through the forming hole, eliminating the air in the blank, making the blank cavity and the blank structure in the forming hole more uniform. When the perforating mandrel passes through the blank processing variable diameter hole, the movement of the perforating mandrel is more stable, and the perforating mandrel will not be offset due to uneven force in the circumferential direction, ensuring the coaxiality of the variable inner diameter of the hollow tube and the variable outer diameter of the hollow tube, thereby ensuring the high-quality forming of the hollow tube inner diameter variable diameter structure, and the forming process is not affected by the length of the hollow tube, and is suitable for different processing depths of the perforating mandrel, so that the forming device is suitable for variable-section hollow tubes of different lengths, and variable-section hollow tubes with a large depth-to-diameter ratio are also applicable.

[0008] As an improvement of the present invention, the side of the clamping mechanism away from the forming mechanism is provided with a first driving hydraulic cylinder for driving the clamping mechanism to move, a first guide seat is provided between the first driving hydraulic cylinder and the clamping mechanism, and a plurality of first guide rods are provided between the first guide seat and the forming mechanism. The clamping mechanism is movably connected to the plurality of first guide rods. Through the improvement, the stability of the movement of the clamping mechanism can be guaranteed. When the clamping mechanism moves toward the forming mechanism, the accuracy of the alignment of the forming cavity and the forming hole can be guaranteed. When the clamping mechanism moves away from the forming mechanism to form the hollow tube length structure, the straightness of the hollow tube can be guaranteed, and the quality of the hollow tube can be guaranteed.

[0009] As an improvement of the present invention, the first driving hydraulic cylinder is driven and connected to the clamping mechanism through the first traction rod, and a thimble is provided on the axis of the first traction rod. The thimble is used to abut against the perforating core shaft to form a complete inner diameter of the hollow tube. The end of the thimble away from the perforating core shaft is provided with a spring. Through the improvement, when the length of the hollow tube is stretched, the diameter-changing structure of the inner diameter of the hollow tube will be separated from the forming hole area, thereby causing the end of the perforating core shaft to be in a state without stable support. However, through the design of the thimble, the end of the perforating core shaft can be stably connected when the length of the hollow tube is not stretched. In the forming hole area, the ejector pin abuts against the end of the piercing mandrel. After the end of the piercing mandrel passes through the forming hole area, the stability of the end of the piercing mandrel is ensured, thereby preventing the piercing mandrel from bending downward, and further avoiding the problem of bending the inner diameter of the hollow tube. The design of the spring can ensure the abutment force between the ejector pin and the piercing mandrel, and avoid excessive extrusion between the ejector pin and the piercing mandrel, which may cause deformation of the ejector pin or the piercing mandrel, thereby ensuring high-quality forming of the inner diameter of the hollow tube. At the same time, the ejector pin can also be used to form part of the inner diameter area of ​​the hollow tube.

[0010] As an improvement of the present invention, the clamping mechanism includes a clamping seat movably connected to the first guide rod, an upper mold and a lower mold for forming a forming cavity, the upper mold is movably connected to the upper half of the clamping seat by a hydraulic cylinder, and the lower mold is movably connected to the lower half of the clamping seat by another hydraulic cylinder. Upper positioning pins are provided on both sides of the upper mold, and lower positioning pins are provided on both sides of the lower mold. The upper half of the clamping seat is provided with an upper limit groove connected to the movement limit of the upper positioning pin, and the lower half of the clamping seat is provided with a lower limit groove connected to the movement limit of the lower positioning pin. When the upper positioning pin abuts against the lower end of the upper limit groove, the lower positioning pin and the lower limit When the upper ends of the grooves abut against each other, the upper mold and the lower mold abut against each other to form a forming cavity. Through the improvement, because the outer diameter of the end of the hollow tube is set to be variable diameter, the outer diameter expands toward the end of the hollow tube. After the end of the hollow tube is formed, the upper mold and lower mold structure design that can be separated is adopted. The part can be taken out without damaging the end structure of the hollow tube. When the upper mold and the lower mold are closed, a two-way drive is adopted. There may be a pressure difference between the hydraulic cylinder used to drive the upper mold and the hydraulic cylinder used to drive the lower mold during the driving process. The accuracy of the closing height can be guaranteed by the matching design of the upper positioning pin and the upper limit groove and the matching design of the lower positioning pin and the lower limit groove.

[0011] As another improvement of the present invention, the upper positioning pin is connected to the upper mold by a threaded connection, and the lower positioning pin is also connected to the lower mold by a threaded connection. The diameter of the end of the upper positioning pin away from the upper mold is greater than the width of the upper limit groove, and the inner side of the end of the upper positioning pin away from the upper mold is against the clamping seat. The diameter of the end of the lower positioning pin away from the lower mold is greater than the width of the lower limit groove, and the inner side of the end of the lower positioning pin away from the lower mold is against the clamping seat. Through the improvement, during the driving process of the hydraulic cylinder, the upper mold and the lower mold may be offset, thereby causing deviation of the forming cavity. By the diameter of the end of the upper positioning pin away from the upper mold is greater than The width of the upper limit groove and the inner side of the end of the upper positioning pin away from the upper mold are against the clamping seat, and the diameter of the end of the lower positioning pin away from the lower mold is greater than the width of the lower limit groove and the inner side of the end of the lower positioning pin away from the lower mold are against the clamping seat. The design can make the upper mold and the lower mold only move longitudinally during the movement process, avoiding lateral offset, thereby ensuring the alignment accuracy between the upper mold and the lower mold, and ensuring high-quality mold closing of the forming cavity. The upper positioning pin and the upper mold are connected by threads, and the lower positioning pin and the lower mold are also connected by threads. When mold closing offset occurs, the upper mold and the lower mold can be adjusted to restore the alignment of the mold closing.

[0012] As another improvement of the present invention, the extrusion mechanism is provided with a second driving hydraulic cylinder on the side away from the forming mechanism for driving the extrusion mechanism to move, and the second driving hydraulic cylinder is provided with two driving hydraulic cylinders, one driving hydraulic cylinder is used to drive the extrusion cylinder to move, and the other driving hydraulic cylinder is used to drive the perforating core shaft to move.

[0013] As another improvement of the present invention, the second driving hydraulic cylinder and the extrusion cylinder are fixedly connected by a connecting seat, a second guide seat is provided between the second driving hydraulic cylinder and the connecting seat, a movable seat is provided between the connecting seat and the forming mechanism, one end of the extrusion cylinder is fixedly connected to the connecting seat, the extrusion end of the extrusion cylinder is movably connected to the movable seat, a plurality of second guide rods are provided between the second guide seat and the forming mechanism, the connecting seat and the movable seat are both movably connected to the plurality of second guide rods, a centering sleeve is provided in the connecting seat, the centering sleeve is sleeved on the perforating core shaft to ensure that the perforating core shaft moves along the axial direction of the forming hole, through the improvement, the stability of the movement of the connecting seat and the movable seat can be guaranteed, when the extrusion cylinder moves toward the blank cavity, the accuracy of the alignment of the extrusion cylinder and the blank cavity can be guaranteed, the force is more uniform and more stable when extruding the blank, and when the perforating core shaft moves toward the forming hole, the coaxiality between the perforating core shaft and the forming hole is guaranteed, thereby ensuring high-quality forming of the inner diameter of the hollow tube.

[0014] As an improvement of the present invention, a compression spring is provided between the movable seat and the connecting seat, and the compression spring is sleeved on the second guide rod. Through the improvement, since there is relative movement between the movable seat and the connecting seat, and the connecting seat needs to drive the movable seat to move, the design of the compression spring can avoid direct collision between the movable seat and the connecting seat, thereby protecting the movable seat and the connecting seat.

[0015] As an improvement of the present invention, the extrusion end of the extrusion cylinder is also connected and fixed with a high-temperature resistant extrusion ring, and the extrusion ring is provided with a through hole for the perforating core shaft to pass through. Through the improvement, the design of the extrusion ring can protect the extrusion quality of the extrusion cylinder while reducing the production cost of the extrusion cylinder. When the extrusion ring is damaged, only the extrusion ring needs to be replaced, and there is no need to replace the entire extrusion cylinder.

[0016] The technical solution adopted by the present invention to solve the above-mentioned problem is a hot extrusion and drawing forming method for preparing a hollow tube with a variable cross-section, which is applicable to a hot extrusion and drawing forming device for preparing a hollow tube with a variable cross-section, and the steps are as follows:

[0017] S1: drives the upper mold and the lower mold to close the mold;

[0018] S2: Start the first driving hydraulic cylinder to drive the clamping mechanism to move toward the forming mechanism and align the forming cavity with the forming hole.

[0019] Arrive and connect;

[0020] S3: Close the first driving hydraulic cylinder;

[0021] S4: placing the blank heated to a suitable temperature in the blank cavity;

[0022] S5: Start the second driving hydraulic cylinder, and the connecting seat drives the extrusion cylinder to move toward the billet cavity;

[0023] S6: The connecting seat and the compression spring are pressed against each other, driving the moving seat to move toward the forming mechanism until the moving seat and the forming mechanism are aligned.

[0024] offset;

[0025] S7: The connecting seat continues to drive the extrusion cylinder forward, and the extrusion cylinder passes through the moving seat and enters the billet cavity, where it contacts the billet.

[0026] Pause driving the extrusion cylinder;

[0027] S8: Drive the piercing mandrel to move toward the blank cavity until the piercing mandrel penetrates the blank and enters the clamping mechanism and ejector pin.

[0028] Offset each other and suspend driving the punching mandrel;

[0029] S9: Drive the extrusion cylinder to make the extrusion ring squeeze the blank in the blank cavity, deform the blank, and pass through the forming hole to the forming cavity.

[0030] Flow in the opposite direction until the forming cavity is filled;

[0031] S10: Reversely drive the first driving hydraulic cylinder to separate the clamping mechanism from the forming mechanism. Under the synchronous action of the extrusion cylinder, the bad material is continuously pulled out of the forming hole. The piercing mandrel is also synchronously driven to keep the piercing mandrel in a state of contact with the ejector pin at all times.

[0032] S11: After all the bad materials in the bad material cavity are squeezed out, the hollow tube to be formed is cooled, and the upper mold and the lower mold are separated to make the forming cavity

[0033] Separating from the reduced diameter end portion of the hollow tube, the clamping mechanism continues to move away from the forming mechanism;

[0034] S12: Drive the second driving hydraulic cylinder in reverse, and the hollow tube moves along the perforating core axis toward the second driving hydraulic cylinder.

[0035] After the reduced diameter end of the tube abuts against the formed hole, the perforating core shaft is separated from the hollow tube;

[0036] S13: Remove the hollow tube from the forming mechanism to complete the processing of the hollow tube.

[0037] Compared with the prior art, the advantages of the present invention are: in the production process, the outer diameter variable structure of the hollow tube is extruded by the forming cavity, and the coaxiality of the outer diameter can be guaranteed only by ensuring the coaxiality of the forming cavity structure. The coaxiality of the forming cavity structure is a mold structure, and it only needs to be processed and formed with high precision to be stably applied to the processing of concentric tubes, thereby ensuring the coaxiality of the outer diameter. The inner diameter variable structure of the hollow tube is formed by perforating the perforating mandrel, and the coaxiality of the different outer diameters of the perforating mandrel and the coaxiality of the perforating mandrel and the outer wall of the hollow tube need to be ensured to ensure the coaxiality of the inner diameter of the hollow tube. First, the perforating mandrel is also a mold structure, and can be made of high-strength material that is not easily deformed. At the same time, during the processing, a slow wire walking method with a longer cycle is used for processing. The process ensures the dimensional accuracy of the perforating mandrel and the coaxiality of different outer diameters, and then the blank is extruded in the blank cavity and moves toward the forming hole, so that the blank is compressed and gathered through the forming hole, eliminating the air in the blank, making the blank cavity and the blank structure in the forming hole more uniform. When the perforating mandrel passes through the blank processing variable diameter hole, the movement of the perforating mandrel is more stable, and the perforating mandrel will not be offset due to uneven force in the circumferential direction, ensuring the coaxiality of the variable inner diameter of the hollow tube and the variable outer diameter of the hollow tube, thereby ensuring the high-quality forming of the hollow tube inner diameter variable diameter structure, and the forming process is not affected by the length of the hollow tube, and is suitable for different processing depths of the perforating mandrel, so that the forming device is suitable for variable-section hollow tubes of different lengths, and variable-section hollow tubes with a large depth-to-diameter ratio are also applicable. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0039] Figure 2 It is a schematic cross-sectional view of the overall structure of the present invention in the preparation stage.

[0040] Figure 3 It is a schematic diagram of the connection structure of the forming mechanism in the initial stage of extrusion of the present invention.

[0041] Figure 4 It is a schematic diagram of the structure in which the ejector pin and the piercing core shaft of the present invention abut against each other.

[0042] Figure 5 It is a schematic diagram of the cross-sectional structure of the clamping mechanism of the present invention.

[0043] Figure 6 It is a schematic cross-sectional structural diagram of the extrusion mechanism of the present invention.

[0044] Figure 7 It is a structural schematic diagram of the hollow tube during molding of the present invention.

[0045] As shown in the figure: 1. forming mechanism, 1.1. blank cavity, 1.2. forming hole, 2. clamping mechanism, 2.1. forming cavity, 2.2. clamping seat, 2.2.1. upper limit groove, 2.2.2. lower limit groove, 2.3. upper die, 2.3.1. upper positioning pin, 2.4. lower die, 2.4.1. lower positioning pin, 3. extrusion mechanism, 3.1. extrusion cylinder, 3.1.1. extrusion ring, 3.1.2. through hole, 3.2. perforated core shaft, 4. first driving hydraulic cylinder, 4.1. traction rod, 4.2. ejector pin, 4.2.1. centering hole, 4.3. spring, 5. first guide seat, 6. first guide rod, 7. second driving hydraulic cylinder, 8. connecting seat, 8.1. centering sleeve, 9. second guide seat, 10. moving seat, 11. second guide rod, 12. compression spring, 13. hollow tube. DETAILED DESCRIPTION

[0046] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0047] like Figure 1-3 As shown, a hot extrusion forming device for preparing a hollow tube with a variable cross-section includes a forming mechanism 1, a clamping mechanism 2 and an extrusion mechanism 3. The forming mechanism 1 is fixed, the clamping mechanism 2 is arranged on one side of the forming mechanism 1, and the extrusion mechanism 3 is arranged on the other side of the forming mechanism 1. The forming mechanism 1 is provided with a blank cavity 1.1 for placing the heated blank. The blank cavity 1.1 is provided with a forming hole 1.2 with an outer diameter of the forming hollow tube 13 on the side close to the clamping mechanism 2. The clamping mechanism 2 is provided with a forming hole 1.2 with an outer diameter of the forming hollow tube 13 on the side close to the forming mechanism 1. The outer diameter of the end of the hollow tube 13 is variable, and the outer diameter expands toward the end of the hollow tube 13. The clamping mechanism 2 is connected and moved along the axis of the forming hole 1.2. The extrusion mechanism 3 is provided with an extrusion cylinder 3.1 and a perforating core shaft 3.2. The extrusion cylinder 3.1 is movably inserted into the billet cavity 1.1 for extruding the billet toward the forming hole 1.2. The perforating core shaft 3.2 is movably connected to the axis of the forming hole 1.2 for forming the inner diameter of the hollow tube 13. The inner diameter of the hollow tube 13 is variable.

[0048] A first driving hydraulic cylinder 6 for driving the clamping mechanism 2 to move is provided on the side of the clamping mechanism 2 away from the forming mechanism 1. A first guide seat 5 is provided between the first driving hydraulic cylinder 6 and the clamping mechanism 2. A plurality of first guide rods 6 are provided between the first guide seat 5 and the forming mechanism 1. The clamping mechanism 2 is movably connected to the plurality of first guide rods 6.

[0049] like Figure 2 、 Figure 4As shown, the first driving hydraulic cylinder 6 is driven and connected to the clamping mechanism 2 through a traction rod 4.1, and a pin 4.2 is provided on the axis of the traction rod 4.1. The pin 4.2 is used to abut against the perforating core shaft 3.2 to form a complete inner diameter of the hollow tube 13. A spring 4.3 is provided on the end of the pin 4.2 away from the perforating core shaft 3.2. The end of the perforating core shaft 3.2 abutting against the pin 4.2 is tapered, which can better pass through the blank. At the same time, a centering hole 4.2.1 is provided on the end of the pin 4.2 abutting against the perforating core shaft 3.2, which can better ensure the centering of the perforating core shaft 3.2 and keep the perforating core shaft 3.2 coaxial with the inner diameter of the hollow tube 13 when forming the hollow tube 13.

[0050] like Figure 1 、 Figure 2 、 Figure 5 As shown, the clamping mechanism 2 includes a clamping seat 2.2 movably connected to the first guide rod 6, an upper die 2.3 and a lower die 2.4 for forming a forming cavity 2.1, the upper die 2.3 is movably connected to the upper half of the clamping seat 2.2 by a hydraulic cylinder, and the lower die 2.4 is movably connected to the lower half of the clamping seat 2.2 by another hydraulic cylinder. Upper positioning pins 2.3.1 are provided on both sides of the upper die 2.3, and lower positioning pins 2.3.1 are provided on both sides of the lower die 2.4. The upper half of the clamping seat 2.2 is provided with an upper limit groove 2.2.1 connected to the upper positioning pin 2.3.1 for movement and limiting, and the lower half of the clamping seat 2.2 is provided with a lower limit groove 2.2.2 connected to the lower positioning pin 2.4.1 for movement and limiting. When the upper positioning pin 2.3.1 abuts against the lower end of the upper limit groove 2.2.1 and the lower positioning pin 2.4.1 abuts against the upper end of the lower limit groove 2.2.2, the upper mold 2.3 and the lower mold are aligned. 2.4 are against each other to form a forming cavity 2.1, the upper positioning pin 2.3.1 is connected to the upper die 2.3 by a threaded connection, and the lower positioning pin 2.4.1 is also connected to the lower die 2.4 by a threaded connection. The diameter of the end of the upper positioning pin 2.3.1 away from the upper die 2.3 is greater than the width of the upper limit groove 2.2.1 and the inner side of the end of the upper positioning pin 2.3.1 away from the upper die 2.3 is against the clamping seat 2.2, and the lower positioning pin 2.4.1 is away from the lower die 2 .4, the diameter of one end is larger than the width of the lower limit groove 2.2.2 and the inner side of the end of the lower positioning pin 2.4.1 away from the lower mold 2.4 is against the clamping seat 2.2. Two upper positioning pins 2.3.1 are provided on both sides of the upper mold 2.3, and two lower positioning pins 2.4.1 are provided on both sides of the lower mold 2.4, which can better ensure the stability of the upper positioning pin 2.3.1 on the movement of the upper mold 2.3 and the stability of the lower positioning pin 2.4.1 on the movement of the lower mold 2.4.

[0051] like Figure 1 、 Figure 2 、 Figure 6As shown, the extrusion mechanism 3 is provided with a second driving hydraulic cylinder 7 for driving the extrusion mechanism 3 to move on the side away from the forming mechanism 1. The second driving hydraulic cylinder 7 is provided with two driving hydraulic cylinders, one driving hydraulic cylinder is used to drive the extrusion cylinder 3.1 to move, and the other driving hydraulic cylinder is used to drive the perforation core shaft 3.2 to move. The second driving hydraulic cylinder 7 is fixedly connected to the extrusion cylinder 3.1 through a connecting seat 8. A second guide seat 9 is provided between the second driving hydraulic cylinder 7 and the connecting seat 8. A moving seat 10 is provided between the connecting seat 8 and the forming mechanism 1. One end of the extrusion cylinder 3.1 is fixedly connected to the connecting seat 8, and the extrusion end of the extrusion cylinder 3.1 is movably connected to the moving seat 1 0, a plurality of second guide rods 11 are provided between the second guide seat 9 and the forming mechanism 1, the connecting seat 8 and the movable seat 10 are both movably connected to the plurality of second guide rods 11, a centering sleeve 8.1 is provided in the connecting seat 8, the centering sleeve 8.1 is sleeved on the perforating core shaft 3.2 to ensure that the perforating core shaft 3.2 moves along the axial direction of the forming hole 1.2, a compression spring 12 is provided between the movable seat 10 and the connecting seat 8, the compression spring 12 is sleeved on the second guide rod 11, the extrusion end of the extrusion cylinder 3.1 is also connected and fixed with a high-temperature resistant extrusion ring 3.1.1, and the extrusion ring 3.1.1 is provided with a through hole 3.1.2 for the perforating core shaft 3.2 to pass through.

[0052] like Figure 3 As shown, the mold of the blank cavity 1.1 is detachably connected to the forming mechanism 1. During extrusion, the mold of the blank cavity 1.1 is limited in the forming mechanism 1. During unloading and taking out, the mold of the blank cavity 1.1 can be disassembled.

[0053] The first guide rod 6 and the second guide rod 11 can be the same guide rod, which can better ensure the coaxiality of movement.

[0054] like Figure 2 、 Figure 3 、 Figure 7 As shown, a hot extrusion and drawing method for preparing a hollow tube with a variable cross-section is applicable to a hot extrusion and drawing device for preparing a hollow tube with a variable cross-section, and the steps are as follows:

[0055] S1: drives the upper mold 2.3 and the lower mold 2.4 to close the mold;

[0056] S2: Start the first driving hydraulic cylinder 6 to drive the clamping mechanism 2 to move toward the forming mechanism 1, so that the forming cavity 2.1 and the forming hole 1.2 are aligned and connected;

[0057] S3: Close the first driving hydraulic cylinder 6;

[0058] S4: placing the blank heated to a suitable temperature in the blank cavity 1.1;

[0059] S5: Start the second driving hydraulic cylinder 7, and the connecting seat 8 drives the extrusion cylinder 3.1 to move toward the billet cavity 1.1;

[0060] S6: The connecting seat 8 abuts against the compression spring 12, driving the movable seat 10 to move toward the forming mechanism 1 until the movable seat 10 abuts against the forming mechanism 1;

[0061] S7: The connecting seat 8 continues to drive the extrusion cylinder 3.1 to move forward, and the extrusion cylinder 3.1 passes through the moving seat 10 and enters the billet cavity 1.1.

[0062] When the billet is pressed against the billet, the driving of the extrusion cylinder 3.1 is stopped;

[0063] S8: Drive the piercing mandrel 3.2 to move toward the blank cavity 1.1 until the piercing mandrel 3.2 penetrates the blank and enters the clamping position.

[0064] The mechanism 2 abuts against the ejector pin 4.2, pausing the driving of the punching mandrel 3.2;

[0065] S9: Drive the extrusion cylinder 3.1 to make the extrusion ring 3.1.1 extrude the blank in the blank cavity 1.1, deform the blank, and form it.

[0066] The fluid flows from the hole 1.2 toward the forming cavity 2.1 until the forming cavity 2.1 is filled.

[0067] S10: Reverse drive the first driving hydraulic cylinder 6 to separate the clamping mechanism 2 from the forming mechanism 1. Under the synchronous action of the extrusion cylinder 3.1, the bad material is continuously pulled out from the forming hole 1.2. The perforating mandrel 3.2 is also synchronously driven.

[0068] 3.2 always maintains a state of contact with ejector pin 4.2;

[0069] S11: After all the blanks in the blank cavity are squeezed out, the hollow tube 13 to be formed is cooled, and the upper mold 2.3 and the lower mold 2.4 are separated.

[0070] The forming cavity 2.1 is separated from the reduced diameter end of the hollow tube 13, and the clamping mechanism 2 continues to move away from the forming mechanism 1;

[0071] S12: The second driving hydraulic cylinder 7 is driven in the reverse direction. The hollow tube 13 moves toward the second driving hydraulic cylinder 7 along with the piercing mandrel 3.2. After the reduced diameter end of the hollow tube 13 abuts against the forming hole 1.2, the piercing mandrel 3.2 separates from the hollow tube 13.

[0072] S13: Remove the hollow tube 13 from the forming mechanism 1, completing the processing of the hollow tube 13.

[0073] The above description is merely a description of the preferred embodiment of the present invention and is not to be construed as limiting the scope of the claims. The present invention is not limited to the above embodiment, and variations in the specific structure are permitted. Any variations within the scope of the independent claims of the present invention are also within the scope of protection of the present invention.

Claims

1. A hot extrusion and drawing device for preparing hollow tubes with variable cross-sections, characterized in that: The invention comprises a forming mechanism (1), a clamping mechanism (2) and an extrusion mechanism (3), wherein the forming mechanism (1) is fixedly arranged, the clamping mechanism (2) is arranged on one side of the forming mechanism (1), and the extrusion mechanism (3) is arranged on the other side of the forming mechanism (1), the forming mechanism (1) is provided with a blank cavity (1.1) for placing heated blanks, the blank cavity (1.1) is provided with a forming hole (1.2) of the outer diameter of a forming hollow tube (13) on the side close to the clamping mechanism (2), and the clamping mechanism (2) is provided with a forming cavity (2.2) of the end of the forming hollow tube (13) on the side close to the forming mechanism (1). 1), the outer diameter of the end of the hollow tube (13) is configured to be variable in diameter, and the outer diameter expands toward the end of the hollow tube (13); the clamping mechanism (2) is movably connected along the axial direction of the forming hole (1.2); the extrusion mechanism (3) is provided with an extrusion cylinder (3.1) and a perforating core shaft (3.2); the extrusion cylinder (3.1) is movably inserted into the billet cavity (1.1) for extruding the billet toward the forming hole (1.2); the perforating core shaft (3.2) is movably connected to the axis of the forming hole (1.2) for forming the inner diameter of the hollow tube (13); and the inner diameter of the hollow tube (13) is configured to be variable in diameter.

2. A hot extrusion and drawing forming device for preparing a hollow tube with a variable cross-section according to claim 1, characterized in that: A first driving hydraulic cylinder (4) for driving the clamping mechanism (2) to move is provided on a side of the clamping mechanism (2) away from the forming mechanism (1); a first guide seat (5) is provided between the first driving hydraulic cylinder (4) and the clamping mechanism (2); a plurality of first guide rods (6) are provided between the first guide seat (5) and the forming mechanism (1); and the clamping mechanism (2) is movably connected to the plurality of first guide rods (6).

3. The hot extrusion and drawing forming device for preparing a hollow tube with a variable cross-section according to claim 2, characterized in that: The first driving hydraulic cylinder (4) is connected to the clamping mechanism (2) through a traction rod (4.1). A thimble (4.2) is provided on the axis of the traction rod (4.1). The thimble (4.2) is used to abut against the perforating core shaft (3.2) to form a complete inner diameter of the hollow tube (13). A spring (4.3) is provided at one end of the thimble (4.2) away from the perforating core shaft (3.2).

4. The hot extrusion and drawing forming device for preparing a hollow tube with a variable cross-section according to claim 2, characterized in that: The clamping mechanism (2) comprises a clamping seat (2.2) movably connected to a first guide rod (6), an upper die (2.3) and a lower die (2.4) for forming a forming cavity (2.1), the upper die (2.3) being movably connected to the upper half of the clamping seat (2.2) via a hydraulic cylinder, the lower die (2.4) being movably connected to the lower half of the clamping seat (2.2) via another hydraulic cylinder, upper positioning pins (2.3.1) being provided on both sides of the upper die (2.3), and lower positioning pins (2.4.1) being provided on both sides of the lower die (2.4). The upper half of the clamping seat (2.2) is provided with an upper limit groove (2.2.1) connected to the upper positioning pin (2.3.1) for movement and limitation, and the lower half of the clamping seat (2.2) is provided with a lower limit groove (2.2.2) connected to the lower positioning pin (2.4.1) for movement and limitation. When the upper positioning pin (2.3.1) abuts against the lower end of the upper limit groove (2.2.1) and the lower positioning pin (2.4.1) abuts against the upper end of the lower limit groove (2.2.2), the upper mold (2.3) and the lower mold (2.4) abut against each other to form a forming cavity (2.1).

5. The hot extrusion and drawing forming device for preparing a hollow tube with a variable cross-section according to claim 4, characterized in that: The upper positioning pin (2.3.1) is connected to the upper die (2.3) by a threaded connection, and the lower positioning pin (2.4.1) is also connected to the lower die (2.4) by a threaded connection. The diameter of the end of the upper positioning pin (2.3.1) away from the upper die (2.3) is greater than the width of the upper limit groove (2.2.1), and the inner side of the end of the upper positioning pin (2.3.1) away from the upper die (2.3) abuts against the clamping seat (2.2). The diameter of the end of the lower positioning pin (2.4.1) away from the lower die (2.4) is greater than the width of the lower limit groove (2.2.2), and the inner side of the end of the lower positioning pin (2.4.1) away from the lower die (2.4) abuts against the clamping seat (2.2).

6. The hot extrusion and drawing forming device for preparing a hollow tube with a variable cross-section according to claim 1, characterized in that: A second driving hydraulic cylinder (7) for driving the extrusion mechanism (3) to move is provided on a side of the extrusion mechanism (3) away from the forming mechanism (1). Two driving hydraulic cylinders are provided inside the second driving hydraulic cylinder (7), one driving hydraulic cylinder for driving the extrusion cylinder (3.1) to move, and the other driving hydraulic cylinder for driving the perforating core shaft (3.2) to move.

7. The hot extrusion and drawing device for preparing a hollow tube with a variable cross-section according to claim 6, characterized in that: The second driving hydraulic cylinder (7) and the extrusion cylinder (3.1) are fixedly connected via a connecting seat (8); a second guide seat (9) is provided between the second driving hydraulic cylinder (7) and the connecting seat (8); a movable seat (10) is provided between the connecting seat (8) and the forming mechanism (1); one end of the extrusion cylinder (3.1) is fixedly connected to the connecting seat (8); the extrusion end of the extrusion cylinder (3.1) is movably connected to the movable seat (10); a plurality of second guide rods (11) are provided between the second guide seat (9) and the forming mechanism (1); the connecting seat (8) and the movable seat (10) are both movably connected to the plurality of second guide rods (11); a centering sleeve (8.1) is provided in the connecting seat (8); the centering sleeve (8.1) is sleeved on the perforating core shaft (3.2) to ensure that the perforating core shaft (3.2) moves along the axial direction of the forming hole (1.2).

8. The hot extrusion and drawing forming device for preparing a hollow tube with a variable cross-section according to claim 7, characterized in that: A compression spring (12) is provided between the movable seat (10) and the connecting seat (8), and the compression spring (12) is sleeved on the second guide rod (11).

9. The hot extrusion and drawing forming device for preparing a hollow tube with a variable cross-section according to claim 6, characterized in that: A high-temperature resistant extrusion ring (3.1.1) is also connected and fixed to the extrusion end of the extrusion cylinder (3.1), and a through hole (3.1.2) for a piercing core shaft (3.2) to pass through is provided on the extrusion ring (3.1.1).

10. A hot extrusion and drawing method for preparing a hollow tube with a variable cross-section, characterized in that: A hot extrusion and drawing forming device for preparing a hollow tube with a variable cross-section according to any one of claims 1 to 9, comprising the following steps: S1: drives the upper mold (2.3) and the lower mold (2.4) to close the mold; S2: Activate the first driving hydraulic cylinder (4), drive the clamping mechanism (2) to move toward the forming mechanism (1), and make the forming cavity (2.1) and the forming hole (1.2) collide with each other and connect; S3: closing the first driving hydraulic cylinder (4); S4: placing the blank heated to a suitable temperature in the blank cavity (1.1); S5: Start the second driving hydraulic cylinder (7), and the connecting seat (8) drives the extrusion cylinder (3.1) to move toward the billet cavity (1.1); S6: The connecting seat (8) and the compression spring (12) abut against each other, driving the movable seat (10) to move toward the forming mechanism (1) until the movable seat (10) abuts against the forming mechanism (1); S7: The connecting seat (8) continues to drive the extrusion cylinder (3.1) to move forward, and the extrusion cylinder (3.1) passes through the moving seat (10) and enters the billet cavity (1.1), contacts the billet, and the driving of the extrusion cylinder (3.1) is stopped; S8: driving the piercing mandrel (3.2) to move toward the blank cavity (1.1) until the piercing mandrel (3.2) penetrates the blank and enters the clamping mechanism (2) and contacts the ejector pin (4.2), and then pausing the driving of the piercing mandrel (3.2); S9: driving the extrusion cylinder (3.1) to cause the extrusion ring (3.1.1) to extrude the blank in the blank cavity (1.1), causing the blank to deform and flow through the forming hole (1.2) toward the forming cavity (2.1) until the forming cavity (2.1) is filled. S10: Reverse drive the first driving hydraulic cylinder (4) to separate the clamping mechanism (2) from the forming mechanism (1), and under the synchronous action of the extrusion cylinder (3.1), the bad material is continuously pulled out from the forming hole (1.2). The piercing mandrel (3.2) is also driven synchronously, so that the piercing mandrel (3.2) always maintains a state of contact with the ejector pin (4.2); S11: After all the blanks in the blank cavity are extruded, the hollow tube (13) to be formed is cooled, and the upper mold (2.3) and the lower mold (2.4) are separated, so that the forming cavity (2.1) and the reduced diameter end of the hollow tube (13) are separated. The clamping mechanism (2) continues to move away from the forming mechanism (1); S12: driving the second driving hydraulic cylinder (7) in the reverse direction, the hollow tube (13) moves along with the perforating core shaft (3.2) toward the second driving hydraulic cylinder (7), and after the reduced diameter end of the hollow tube (13) abuts against the forming hole (1.2), the perforating core shaft (3.2) and the hollow tube (13) are separated; S13: Remove the hollow tube (13) from the forming mechanism (1) to complete the processing of the hollow tube (13).

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