Hot-state air pressure forming die and method for variable-cross-section 3D bent pipe part

Abstract

The invention relates to an air pressure forming die and method for hot-state metal pipe parts. The air pressure forming die comprises an upper die system, a lower die system, a sealing inflation system and a pressure head cooling system. The mold is opened and closed through longitudinal displacement of the upper mold system on the lower mold system, and an air pressure forming space is formed. And the pressure head cooling system provides rapid heat dissipation for the end part of the pipe blank, so that fixing and pressing are ensured. The sealed inflation system achieves high-pressure segmented pressurization inflation through a jacking type butt joint disc and a sealed punch. Lateral deviation is prevented through the upper die guide plate and the lower die guide plate in the whole forming process, and finally efficient and accurate forming of the part is completed through self-cooling. Through innovative design and fine control, the forming quality is improved, the mold stability is enhanced, the production efficiency is improved, and the cooling effect is optimized.

Description

Technical Field

[0001] The invention relates to a pneumatic forming die, and in particular to a hot pneumatic forming die and method for variable-section 3D curved tube parts. Background Art

[0002] The existing pneumatic forming mold usually includes an upper mold insert and a lower mold insert, which are relatively displaced by guide pins and guide sleeves to open and close the mold. The upper mold insert and the lower mold insert are closed to form a forming space for accommodating the hot metal tube blank and performing pneumatic forming. After that, the inflation device injects high-pressure gas into the tube blank through a cylinder or a manual device. The existing pneumatic forming mold has the following problems:

[0003] Insufficient molding accuracy: In traditional mold design, the fit between the mold blank and the mold is not high, resulting in poor molding accuracy and poor part size consistency. The impact force when the tube blank enters the molding space is large, which can easily cause surface scratches and deformation.

[0004] Poor cooling effect: lack of effective cooling system, the temperature of the end of the tube is difficult to quickly reduce, affecting the forming effect and part quality. Uneven cooling leads to uneven stress distribution inside the parts, affecting the service life.

[0005] Poor mold stability: It is easy to tilt during the mold closing process, affecting the correct position and shape of the mold, and thus affecting the molding quality. Insufficient sealing, high-pressure gas is easy to leak during filling, resulting in unstable molding pressure.

[0006] Low production efficiency: The molding process is complicated, the operation is cumbersome, and the production efficiency is low. The lack of efficient stamping and inflation molding devices prolongs the production cycle.

[0007] Variable cross-section parts are difficult to form: Especially complex 3D curved variable cross-section parts are more difficult to form. The non-uniform cross-section and three-dimensional curved shape of such parts require highly precise mold design to ensure uniform deformation of the material throughout the forming process to avoid cracks and deformation.

[0008] Especially with the rapid development of new energy vehicles, the demand for hot gas expansion parts is growing. After hot gas expansion, the organization of hot-formed high-strength steel changes, which not only achieves lightweight, but also significantly improves the performance of the material and increases the overall strength and stiffness of the vehicle body. The performance improvement of this material is crucial for new energy vehicles because it can reduce the weight of the vehicle while ensuring safety and performance. Therefore, the requirements for hot gas forming molds for such parts are getting higher and higher. Summary of the invention

[0009] In order to solve the deficiencies of the above-mentioned technologies, the present invention provides a hot pneumatic forming die and method for variable-section 3D curved tubular parts.

[0010] In order to solve the above technical problems, the technical solution adopted by the present invention is: a hot gas pressure forming mold for variable cross-section 3D curved tube parts, including an upper mold system, a lower mold system, a sealing and inflating system, and a pressure head cooling system. The upper mold system is longitudinally displaced above the lower mold system so that the upper mold insert located on the upper mold system and the lower mold insert located on the lower mold system are opened and closed. After the upper mold insert and the lower mold insert are molded together, a gas pressure forming space for the hot metal tube parts is formed. The two ports of the gas pressure forming space are extended respectively and connected to the upper mold system at the position. A pressure head space is formed by mutual pre-pressing of the upper pressure head of the mold system and the lower pressure head of the lower mold system. Each pressure head space is connected to a pressure head cooling system with a fluid channel formed jointly on the upper pressure head and the lower pressure head. Fluid is transported through the fluid channel to exchange heat with the hot metal pipe parts in the pressure head space. The port of each pressure head space is respectively connected to a sealed inflation system located on the lower mold system. The sealed inflation system drives a sealed punch connected to the external air supply end through a cylinder pressure component to punch and inflate the port of the hot metal pipe parts.

[0011] Furthermore, the upper mold insert is fixedly connected to the top plate of the upper mold system, and the lower mold insert is fixedly connected to the bottom plate of the lower mold system. The upper mold insert and the lower mold insert are both stepped and matched with each other to form a combined mold. The high-order and low-order transitions of the upper mold insert form a semi-groove for the upper tube blank, and the high-order and low-order transitions of the lower mold insert form a semi-groove for the lower tube blank. The upper tube blank semi-groove and the lower tube blank semi-groove together form an air pressure forming space.

[0012] Furthermore, the outer edges of the upper tube blank half groove and the lower tube blank half groove are both in the shape of a cutting edge, and the high-step upper edge entrance of the upper die insert and the high-step upper edge entrance of the lower die insert are both in the shape of an arc surface.

[0013] Furthermore, the upper ram is movably connected to the top plate by a No. 1 nitrogen spring, and the initial position of the upper ram is driven by the No. 1 nitrogen spring so that the side forming the ram space is downward relative to the upper die insert, and the upper tube blank half groove of the upper die insert and the side forming the ram space of the upper ram are misaligned up and down; the lower ram is connected to the bottom plate, and the side forming the ram space of the lower ram is aligned with the lower tube blank half groove of the lower die insert, and the downward-protruding upper ram pre-presses the hot metal tube parts placed on the lower ram.

[0014] Furthermore, four upper mold guide sleeves are arranged on the top plate of the upper mold system, and four lower mold guide pillars are matched and arranged on the bottom plate of the lower mold system. Each lower mold guide pillar is slidably arranged in an upper mold guide sleeve to realize the longitudinal displacement of the upper mold system above the lower mold system.

[0015] Furthermore, a plurality of upper mold guide plates are arranged on the side of the upper mold insert of the top plate, and the upper mold guide plates simultaneously abut against the lower mold insert after the mold is closed; a plurality of lower mold guide plates are arranged on the side of the lower mold insert of the top plate, and the lower mold guide plates simultaneously abut against the upper mold insert after the mold is closed; the upper part of the lower mold guide plate is clamped in a slot opened on the top plate through a key.

[0016] Furthermore, the pressure head cooling system includes an annular cooling cavity, which surrounds and connects the pressure head space formed after the upper pressure head and the lower pressure head are pre-pressed with each other, and the annular cooling cavity is connected to the fluid joint through a fluid passage in the upper pressure head and the lower pressure head respectively.

[0017] Furthermore, the cylinder pressure assembly includes a hydraulic cylinder, which is mounted on a hydraulic cylinder mounting seat connected to the base plate. A connecting disc is fixedly connected to the hydraulic cylinder. The connecting disc is movably connected to a sealing docking disc through a No. 2 nitrogen spring. The sealing docking disc moves within the upper limit of the connecting disc through a movable guide column. A sealing punch is connected to the piston end of the hydraulic cylinder. The sealing punch is also movably arranged in the center of the sealing docking disc. The sealing punch is connected to the air supply end through a high-pressure air pipe.

[0018] Furthermore, the upper pressure head and the lower pressure head jointly form a sealing end groove at the end, the center of the sealing end groove is the port of the pressure head space, and during stamping and inflation, the sealing docking disc matches and abuts against the sealing end groove, and the sealing punch movably arranged in the sealing docking disc can pass through the sealing docking disc and punch to the port of the pressure head space.

[0019] A forming method of a hot gas pressure forming mold for a variable-section 3D curved tube-like part, comprising a hot gas pressure forming mold for a variable-section 3D curved tube-like part, wherein the forming method is as follows: in the placement and pressing stage of a tube blank, the heat is fixed and continuously and rapidly dissipated based on a pressure head cooling system; after the tube blank is placed and pressed, the tube blank is guided and returned to its position based on the mutual cooperation of an upper tube blank half groove and a lower tube blank half groove; then, a sealing end groove formed by a pressure head cooling system is pushed into a top-in-type docking disc based on a sealing inflation system, and a sealing punch is used to perform high-pressure segmented pressurization and inflation on the stamping docking of the tube blank; during inflation, an upper die guide plate and a lower die guide plate are used to prevent lateral deviation after mold closing; and finally, self-cooling is used to complete part molding.

[0020] The present invention discloses a hot gas pressure forming mold and method for variable-section 3D curved tube parts, which at least include the following benefits: improving the forming quality and the blade-shaped outer edge design. Ensuring that the mold blank fits the mold shape better and improving the forming accuracy and sealing effect. The arc inlet design reduces the impact force of the tube blank entering the forming space and improves the surface quality. A pressure head cooling system is added to quickly reduce the temperature of the tube blank end, fix the shape, and improve the forming effect. The nitrogen spring is used to drive the upper pressure head downward to enhance the end fixing effect and ensure the spatial stability of the pressure head. The guide plate and guide column design are used to prevent the mold from tilting and ensure the mold closing accuracy and stability. A sealed docking disc is used to ensure the sealing during the high-pressure gas filling process and prevent gas leakage. Improve production efficiency, the hydraulic cylinder and the sealing punch work together to achieve fast and effective stamping and inflation forming, segmented pressurization and cooling process, optimize the forming process, and shorten production time. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0022] Figure 2 It is a structural diagram of the upper mold system.

[0023] Figure 3 It is a structural diagram of the lower mold system.

[0024] Figure 4 It is a structural schematic diagram of the upper die insert and the pressure head cooling system.

[0025] Figure 5 It is a schematic diagram of the structure of the lower mold insert.

[0026] Figure 6 Schematic diagram of the initial position structure of the upper pressure head.

[0027] Figure 7 A schematic diagram of the structure of a sealed inflation system formed in a pressure head cooling system.

[0028] Figure 8 It is a schematic diagram of the structure of the upper pressure head.

[0029] Fig. 9 It is a structural schematic diagram of the sealing inflation system connecting the lower mold system through the pressure head cooling system.

[0030] Fig.10 for Fig. 9 An enlarged schematic diagram of the structure of the part in the middle circle.

[0031] Fig.11 It is a structural diagram of the sealing and inflation system.

[0032] Fig.12 It is a structural diagram of embodiment 2.

[0033] In the figure: A, upper die system; B, lower die system; C, sealing and inflation system; D, ram cooling system; 110, upper die insert; 111, upper tube blank half groove; 120, top plate; 121, slot; 130, upper ram; 140, No. 1 nitrogen spring; 150, upper die guide sleeve; 160, upper die guide plate; 210, lower die insert; 211, lower tube blank half groove; 220, bottom plate; 230, lower ram; 240 , lower die guide pin; 250, lower die guide plate; 310, pressure head space; 320, fluid passage; 330, fluid connector; 400, hydraulic cylinder; 410, hydraulic cylinder mounting seat; 420, connecting disc; 430, No. 2 nitrogen spring; 440, high-pressure air pipe; 450, sealing docking disc; 460, movable guide pin; 470, sealing punch; 500, upper pressure plate; 510, lower pressure plate; 1231, sealing end groove. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0035] Embodiment 1;

[0036] like Figure 1 A hot gas pressure forming mold for a variable cross-section 3D curved tube-like part shown in the figure comprises an upper mold system A, a lower mold system B, a sealing and inflating system C, and a pressure head cooling system D. The upper mold system A is longitudinally displaced above the lower mold system B, so that the upper mold insert 110 located on the upper mold system A and the lower mold insert 210 located on the lower mold system B are opened and closed. After the upper mold insert 110 and the lower mold insert 210 are molded together, a gas pressure forming space for the hot metal tube-like part is formed. The two ports of the gas pressure forming space are extended respectively and connected to the upper pressure head 130 and the lower mold of the upper mold system A at the position. The lower pressure heads 230 of system B are pre-pressed to form a pressure head space 310, and each pressure head space 310 is connected to a pressure head cooling system D with a fluid channel jointly formed on the upper pressure head 130 and the lower pressure head 230. The fluid is transported through the fluid channel to exchange heat with the hot metal pipe parts in the pressure head space 310. The port of each pressure head space 310 is respectively connected to a sealing and inflation system C located on the lower mold system. The sealing and inflation system C drives a sealing punch connected to the external air supply end through a cylinder pressure component to punch and inflate the port of the hot metal pipe parts.

[0037] like Figure 2As shown, the upper mold insert 110 is fixedly connected to the top plate 120 of the upper mold system. Four upper mold guide sleeves 150 arranged in the longitudinal direction are also arranged on the top plate 120 of the upper mold system to realize the longitudinal displacement of the upper mold system. A number of upper mold guide plates 160 are abutted against the side of the upper mold insert 110 of the top plate 120. The upper mold guide plates 160 are used to limit the side of the upper mold insert 110 to prevent the upper mold insert 110 from tilting when the mold is closed, thereby affecting the forming effect of hot metal pipe parts. The upper mold guide plates 160 can be connected to the top plate 120 by a fixed key, and can also be fixedly connected by an interference fit, but are not limited to the above methods. In theory, the fixed connection between the two can be achieved. In this embodiment, according to the length of the upper mold insert 110, two upper mold guide plates 160 are evenly distributed on the same side of the upper mold insert 110, which effectively prevents the displacement of the upper mold insert 110 due to the tilting force on this side.

[0038] like Figure 1-3 As shown, the upper mold guide plate 160 abuts against the lower mold insert 210 at the same time after the mold is closed, which effectively prevents the lower mold insert 210 from shifting due to the tilting force on this side; a number of lower mold guide plates 250 are arranged to abut against the side of the lower mold insert 210 of the top plate 120. Similarly, the lower mold guide plate 250 abuts against the upper mold insert 110 at the same time after the mold is closed. In the present embodiment, according to the length of the lower die insert 210, four lower die guide plates 250 are evenly distributed on the same side of the lower die insert 210. The function of the lower die guide plate 250 is the same as that of the upper die guide plate 160. In particular, the upper part of the lower die guide plate 250 is clamped in the slot 121 opened on the top plate 120 through the key 251. The key 251 can ensure that the lower die guide plate 250 is accurately and firmly fixed in the slot 121 of the top plate 120, which can avoid displacement caused by vibration or external force during the mold closing process and ensure the correct position and shape of the mold, thereby increasing the connection stability between the lower die guide plate 250 and the top plate, which helps to better resist the displacement caused by the roll force during the entire mold closing process.

[0039] like Figure 1 and Figure 3 As shown, the lower mold insert 210 is fixedly connected to the bottom plate 220 of the lower mold system, and four lower mold guide pillars 240 are matched and arranged on the bottom plate 220 of the lower mold system. Each lower mold guide pillar 240 is slidably arranged in an upper mold guide sleeve 150 to realize the longitudinal displacement of the upper mold system above the lower mold system, and finally realize the mold closing of the upper mold insert 110 and the lower mold insert 210.

[0040] like Figure 4 and Figure 5As shown, in the structure of the upper mold insert 110 and the lower mold insert 210, the upper mold insert 110 is in the shape of high and low steps, and the upper tube blank half groove 111 is formed at the transition between the high and low steps of the upper mold insert 110. The lower mold insert 210 is also in the shape of high and low steps, and the lower tube blank half groove 211 is formed at the transition between the high and low steps of the lower mold insert 210. Therefore, the upper mold insert and the lower mold insert match each other to form a mold, and the upper tube blank half groove 111 and the lower tube blank half groove 211 are surrounded to form an air pressure forming space, which is the forming space of hot metal tube parts. In particular, in order to improve the forming accuracy, in this embodiment, the outer edge of the upper tube blank half groove 111 and the outer edge of the lower tube blank half groove 211 are both in the shape of a cutting edge, and the high-step upper edge entrance of the upper mold insert 110 and the high-step upper edge entrance of the lower mold insert 210 are both in the shape of an arc surface. Reference Figure 5 In the enlarged part of the circle shown, W represents the blade-shaped outer edge, and S represents the upper edge of the arc surface. Due to the design of the blade-shaped outer edge, the mold blank can better fit the mold shape during the molding process, so that the mold blank can effectively correct the position when entering the upper tube blank semi-groove 111 and the upper tube blank semi-groove 111. At the same time, the blade-shaped outer edge can provide a better sealing effect, enhance the pressure of air pressure molding, and enable the hot metal tube blank to fully fit the inner wall of the mold, thereby improving the molding effect. The arc surface design reduces the impact force of the metal tube blank when entering the molding space at the entrance, which can reduce scratches and deformation on the surface of the tube blank, thereby improving the surface quality of the molded parts. The above design significantly improves the molding quality of hot metal tube parts without increasing the complexity.

[0041] like Figure 2 and Figure 6 As shown, the upper ram 130 is movably connected to the top plate 120 through the No. 1 nitrogen spring 140. The initial position of the upper ram 130 is driven by the No. 1 nitrogen spring 140 to move the side of the upper ram 130 that forms the ram space 310 downward relative to the upper die insert 110, and to make the upper tube blank half groove 111 of the upper die insert 110 and the side of the upper ram 130 that forms the ram space 310 misaligned up and down. Figure 3As shown, the lower ram 230 is connected to the bottom plate 220 , and one side of the ram space 310 formed by the lower ram 230 is aligned with the lower tube blank half groove 211 of the lower die insert 210 , and the downwardly protruding upper ram 130 pre-presses the hot metal tube parts placed on the lower ram 230 . Before mold closing, the hot metal tube parts are first placed in the lower tube blank half groove 211, and the two ends of the hot metal tube parts are fixed in advance by the downward-protruding upper ram 130 to form a ram space 310 with the lower ram 230, and the mold is closed before the upper mold insert 110 and the lower mold insert 210, so as to better control the shape and position of the tube blank, create more favorable conditions for subsequent gas pressure forming, and thus improve the forming effect. After the ram space 310 is formed, the No. 1 nitrogen spring 140 of the upper ram 130 is compressed, and the reaction generated by the No. 1 nitrogen spring 140 drives the upper ram 130 to continuously press the lower ram 230 to ensure the stability of the ram space 310.

[0042] like Figure 7 and Figure 8 As shown, the pressure head cooling system includes an annular cooling cavity 300, which surrounds and connects the pressure head space 310 formed by the upper pressure head 130 and the lower pressure head 230 after pre-pressing each other, and the annular cooling cavity 300 is connected to the fluid connector 330 through the fluid passage 320 in the upper pressure head 130 and the lower pressure head 230 respectively.

[0043] The ram cooling system absorbs the heat from both ends of the hot metal pipe parts by circulating the fluid (usually water or cooling oil or low-temperature gas) in the annular cooling cavity 300. Specifically, the cooling fluid enters the fluid passage 320 inside the upper ram 130 and the lower ram 230 through the fluid joint 330, flows through the annular cooling cavity 300, absorbs the heat from both ends of the metal pipe parts in the process, and then flows back to the cooling system for circulating cooling. In this way, the cooling fluid directly contacts the two ends of the hot metal pipe parts, which can quickly reduce their temperature and harden their texture, making them easier to fix and maintain their shape.

[0044] like Fig. 9 and Fig.11 As shown, the cylinder pressure assembly includes a hydraulic cylinder 400, which is mounted on a hydraulic cylinder mounting seat 410 connected to the base plate 220, and a connecting disc 420 is fixedly connected to the hydraulic cylinder 400, and the connecting disc 420 is movably connected to a sealing docking disc 450 through a No. 2 nitrogen spring 430, and the sealing docking disc 450 is moved to the upper limit position of the connecting disc 420 through a movable guide column 460, and a sealing punch 470 is connected to the piston end of the hydraulic cylinder 400, and the sealing punch 470 is movably arranged in the center of the sealing docking disc 450, and the sealing punch 470 is connected to the air supply end through a high-pressure air pipe 440.

[0045] The upper pressure head 130 and the lower pressure head 230 jointly form a sealing end groove 1231 at the end (for the convenience of display, Fig.10 The upper pressure head 130 is omitted, and the center of the sealing end groove 1231 is the port of the pressure head space 310. During stamping and inflation, the sealing docking disc 450 matches and abuts against the sealing end groove 1231, and the sealing punch 470 movably arranged in the sealing docking disc can pass through the sealing docking disc 450 and punch to the port of the pressure head space 310.

[0046] The cylinder pressure assembly uses the thrust generated by the hydraulic cylinder 400 to achieve the docking of the sealing docking disc 450 with the sealing end groove 1231 of the pressure head space 310. The hydraulic cylinder 400 is mounted on the hydraulic cylinder mounting seat 410 on the bottom plate 220. When the piston of the hydraulic cylinder 400 is activated, it pushes the connecting disc 420, and the connecting disc 420 is movably connected to the sealing docking disc 450 through the second nitrogen spring 430. Under the limiting action of the movable guide post 460, the sealing docking disc 450 can move on the connecting disc 420, so as to achieve accurate docking with the sealing end groove 1231. It should be understood that the movable guide post 460 can move in the guide hole on the connecting disc 420, and realize the limited displacement of the movable guide post 460 through the blocking action of its own block and the guide hole. At the same time, the sealing punch 470 is connected to the air supply end through the high-pressure air pipe 440. When the sealing punch 470 passes through the center of the sealing docking disc 450, it can be punched to the port of the pressure head space 310, so as to achieve stamping and inflation molding. The advantage of such a setting is that the hydraulic cylinder 400 can provide stable and controllable pressure, ensuring that the pressure can be accurately applied to the required position during the stamping and inflation molding process, thereby improving the molding accuracy. At the same time, the matching docking of the sealing docking disc 450 and the sealing end groove 1231 can effectively seal the port of the pressure head space 310, prevent gas leakage, and ensure the stability of the molding pressure. Through the coordinated work of the hydraulic cylinders 400 and the sealing punches 470 on both sides, rapid and effective stamping and inflation molding can be achieved, thereby improving the efficiency of the entire production process. Note that when the sealing punch 470 on one side is inflated, the other side should remain in a non-deflated state. The above design ensures that pressure is quickly applied to the tube blank during the molding process, which helps to improve the dimensional consistency and surface quality of the molded parts.

[0047] Embodiment 2:

[0048] like Fig.12 As shown, based on the first embodiment, the upper mold system A can be longitudinally displaced above the lower mold system B by a press. Specifically, the upper platen 500 of the press is connected through the upper mold system, and the lower platen 510 of the press is connected through the lower mold system.

[0049] The workflow is as follows:

[0050] Pipe making: Complete pipe making and pre-bending of hot-formed steel pipe fittings.

[0051] Placing heated pipe fittings: First, take out the hot-formed steel pipe fittings heated to 930-950 degrees Celsius and place them in the lower pipe blank half groove of the lower die insert of the lower die system.

[0052] Before mold closing: During the downward pressing process of the upper mold system, the upper mold insert and the upper ram move downward as a whole, the upper ram contacts the lower ram first, and presses the end of the tube blank.

[0053] Guiding and returning to position: As the upper die system continues to press down, the upper tube blank half groove and the lower tube blank half groove cooperate with each other to guide the tube blank back to position.

[0054] Before inflation: the upper mold system continues to move downward as a whole, and the upper mold insert and the lower mold insert are 2-20 mm (same distance for different parts) before they are fully molded into place, and the upper mold system stops moving.

[0055] Punch cooling and sealing: While pressing the tube, the punch cooling system on the upper and lower punches is started to quickly dissipate heat from the end of the tube. At the same time, the sealing butt discs of the sealing and inflation system on both sides of the lower die system begin to push inward into the sealing end groove formed by the upper and lower punches to form a constrained environment for the radial expansion force during sealing, and then the sealing punch continues to move forward to complete the sealing.

[0056] Inflation: After the sealing and inflation system is connected, high-pressure gas is filled into the tube blank through the air inlet of the sealing punch. The time is 1-5 seconds (different parts have different times), and the pressure is controlled between 5-25 MPa (different parts have different pressures).

[0057] Complete compression: After inflation is completed, the upper mold system continues to move downward, and the uncompressed part between the upper mold insert and the lower mold insert is compressed.

[0058] Holding pressure and cooling: Finally, continue to increase the pressure to 20-40 MPa and maintain it for 10-40 seconds to ensure that the part is fully cooled and formed inside the mold. The specific setting of pressure and holding time needs to be determined according to the shape, size and thickness of the part.

[0059] After completing the above steps, withdraw the sealing punch and the sealing docking disc of the sealing and inflation system, unlock the upper die insert and the lower die insert, and then you can take out the formed parts.

[0060] It should be noted that this set of molds and its workflow are suitable for hot metal forming of tubes of various materials, including hot-formed high-strength steel, aluminum alloy, magnesium alloy, etc. It can efficiently cope with the hot processing requirements of various tube parts, ensuring that the parts achieve ideal forming effects and mechanical properties during the hot forming process. In other words, whether it is high-strength steel with complex shapes or lightweight alloy materials, the system can accurately control the processing parameters to ensure that each part can achieve precise guidance, uniform cooling and efficient sealing during the hot forming process, thereby obtaining high-quality forming effects.

[0061] The above implementation modes are not limitations of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the scope of the technical solution of the present invention also belong to the protection scope of the present invention.

Claims

1. A hot gas pressure forming die for variable cross-section 3D curved tube parts, characterized in that: The utility model comprises an upper die system, a lower die system, a sealing and inflating system and a ram cooling system. The upper die system is longitudinally displaced above the lower die system so that the upper die insert on the upper die system and the lower die insert on the lower die system are opened and closed. After the upper die insert and the lower die insert are molded together, a pneumatic forming space for hot metal tube parts is formed. The two ends of the pneumatic forming space are extended outward respectively and connected to the ram space formed by the mutual pre-pressing of the upper ram of the upper die system and the lower ram of the lower die system at the respective positions. Each ram space is respectively connected to a ram cooling system with a fluid channel formed jointly by the upper ram and the lower ram. The hot metal tube parts in the ram space are heat exchanged by conveying fluid through the fluid channel. The ports of each ram space are respectively connected to a sealing and inflating system on the lower die system. The sealing and inflating system drives a sealing punch connected to the external air supply end through a cylinder pressure component to punch and inflate the ports of the hot metal tube parts.

2. The hot gas pressure forming die for variable cross-section 3D curved tube parts according to claim 1, characterized in that: The upper mold insert is fixedly connected to the top plate of the upper mold system, and the lower mold insert is fixedly connected to the bottom plate of the lower mold system. The upper mold insert and the lower mold insert are both stepped and matched with each other to form a mold. The high-order and low-order transitions of the upper mold insert form upper tube blank semi-grooves, and the high-order and low-order transitions of the lower mold insert form lower tube blank semi-grooves. The upper tube blank semi-grooves and the lower tube blank semi-grooves together form the air pressure forming space.

3. The hot gas pressure forming die for variable cross-section 3D curved tube parts according to claim 2, characterized in that: The outer edges of the upper tube blank half groove and the lower tube blank half groove are both in the shape of a cutting edge, and the high-step upper edge entrance of the upper die insert and the high-step upper edge entrance of the lower die insert are both in the shape of an arc surface.

4. The hot gas pressure forming die for variable cross-section 3D curved tube parts according to claim 2, characterized in that: The upper ram is movably connected to the top plate by a No. 1 nitrogen spring. The initial position of the upper ram is driven by the No. 1 nitrogen spring so that one side of the upper ram forming the ram space moves downward relative to the upper die insert, and the upper tube blank half groove of the upper die insert and the side of the upper ram forming the ram space are misaligned up and down; the lower ram is connected to the bottom plate, and one side of the lower ram forming the ram space is aligned with the lower tube blank half groove of the lower die insert. The downward-protruding upper ram pre-presses the hot metal tube parts placed on the lower ram.

5. The hot gas pressure forming die for variable cross-section 3D curved tube parts according to claim 2, characterized in that: Four upper die guide sleeves are arranged on the top plate of the upper die system, and four lower die guide pillars are matched and arranged on the bottom plate of the lower die system. Each lower die guide pillar is slidably arranged in an upper die guide sleeve to realize the longitudinal displacement of the upper die system above the lower die system.

6. The hot gas pressure forming die for variable cross-section 3D curved tube parts according to claim 2, characterized in that: A plurality of upper die guide plates are disposed on the side of the upper die insert of the top plate, and the upper die guide plates simultaneously abut against the lower die insert after the mold is closed; a plurality of lower die guide plates are disposed on the side of the lower die insert of the top plate, and the lower die guide plates simultaneously abut against the upper die insert after the mold is closed; the upper part of the lower die guide plate is clamped in a clamping groove provided on the top plate through a clamping key.

7. The hot gas pressure forming die for variable cross-section 3D curved tube parts according to claim 1, characterized in that: The pressure head cooling system includes an annular cooling cavity, which surrounds and connects the pressure head space formed by the upper pressure head and the lower pressure head after pre-pressing each other, and the annular cooling cavity is connected to the fluid joint through a fluid passage in the upper pressure head and the lower pressure head respectively.

8. The hot gas pressure forming die for variable cross-section 3D curved tube parts according to claim 7, characterized in that: The cylinder pressure assembly includes a hydraulic cylinder, which is mounted on a hydraulic cylinder mounting seat connected to a base plate, a connecting disc being fixedly connected to the hydraulic cylinder, the connecting disc being movably connected to a sealing docking disc via a No. 2 nitrogen spring, the sealing docking disc being moved within the upper limit position of the connecting disc via a movable guide column, a sealing punch being connected to the piston end of the hydraulic cylinder, the sealing punch being movably disposed through the center of the sealing docking disc, and the sealing punch being connected to the air supply end via a high-pressure air pipe.

9. The hot gas pressure forming die for variable cross-section 3D curved tube parts according to claim 8, characterized in that: The upper pressure head and the lower pressure head jointly form a sealing end groove at the end, the center of the sealing end groove is the port of the pressure head space, and during stamping and inflation, the sealing docking disc matches and abuts against the sealing end groove, and the sealing punch movably arranged in the sealing docking disc can pass through the sealing docking disc and punch to the port of the pressure head space.

10. A forming method of a hot gas pressure forming die for a variable cross-section 3D curved tube part, characterized in that: The hot gas pressure forming die for a variable cross-section 3D curved tube-like part according to any one of claims 1 to 9, wherein the forming method is: During the placement and pressing stage of the tube billet, the cooling system of the pressure head is used to fix and continuously and rapidly dissipate heat. After the placement and pressing of the tube billet is completed, the tube billet is corrected and returned to its position based on the cooperation between the upper tube billet half groove and the lower tube billet half groove. Then, the sealing end groove formed by the pressure head cooling system is pushed into the jacking-type docking disc based on the sealing inflation system, and the sealed punch is used to perform high-pressure segmented pressurization and inflation on the stamping docking of the tube billet. During the inflation period, the upper die guide plate and the lower die guide plate are used to prevent lateral deviation after mold closing. Finally, self-cooling is used to complete the part forming.

Images