A device and process for integrally forming a thin-walled cap-shaped part

Abstract

The present invention discloses a device and process for integrally forming a thin-walled cap-shaped part. The device comprises a base, a column, and a main press. A first press is provided on the top of the base, a core mold is fixedly connected to the top output shaft end of the first press, and a water-cooling circulation system is provided in the core mold; a lower die seat is fixedly provided on the column, a concave mold is fixedly installed on the top surface of the lower die seat, a first electrode plate is provided on the inner bottom side of the concave mold, and an ultrasonic vibration device is provided on the top surface of the lower die seat; an upper die seat is fixedly connected to the bottom output end of the main press, an outer punch is fixedly provided on the bottom surface of the upper die seat, an air-cooling circulation system is provided in the outer punch, and a second electrode plate is provided at the bottom of the outer punch; a second press is fixedly provided in the upper die seat, and an inner punch is fixedly connected to the bottom output end of the second press. The present invention can form an integrated thin-walled cap-shaped part structure in a short process and with high precision, achieving near-net-shape forming with minimal or no cutting processing.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal extrusion forming, and in particular relates to an integrated forming device and process for a thin-walled cap-shaped part. Background Art

[0002] Compared to other hot working processes such as casting and welding, forging offers advantages such as superior material mechanical properties, high forming precision, high material utilization, and the ability to form parts in one piece. It is currently widely used in aerospace, new energy vehicles, military applications, and the processing and forming of precision instruments. This integrated forging process overcomes the porosity and shrinkage that occur within castings during the casting process, as well as fatigue-weakened areas caused by welds in welded parts. Forging uses plastic deformation to break up coarse grains, eliminating internal defects such as porosity and shrinkage. This improves the material's strength, toughness, and fatigue life, and can orient metal flow lines along the part's contours to avoid stress concentration. However, for thin-walled workpieces (thickness ≤ 5 mm), uneven metal flow during the forging process can easily lead to localized thinning, folding, or cracking, typically resulting in low yields.

[0003] In recent years, with the advent of energy conservation, emission reduction, and green manufacturing, near-net-shape forming technology has become a mainstream development in the manufacturing industry, aiming to improve material utilization, reduce subsequent processing times, reduce costs, and enhance production efficiency. With the development of precision forging technology, numerical simulation, new materials, and advanced equipment, near-net-shape forging technology has made significant progress. Near-net-shape forging technology is developing towards high precision, high efficiency, low energy consumption, and intelligent technology. In the future, it will play a greater role in high-end manufacturing, gradually replacing traditional cutting and conventional forging processes.

[0004] With the development of the automotive industry, thin-walled cap-shaped parts are in widespread demand as automotive crash boxes. However, current manufacturing methods typically use thin-sheet welding, which is time-consuming and labor-intensive. This process can easily lead to stress concentration at the weld seam, resulting in significant fluctuations in mechanical properties. Traditional extrusion dies are difficult to produce large, thin-walled cap-shaped parts, and controlling the shape accuracy of the thin walls is challenging. There is an urgent need for an efficient, one-piece forming device and process for high-precision, thin-walled cap-shaped parts. Summary of the Invention

[0005] In order to solve the above problems, the patent of the present invention provides an integrated forming device and process for thin-walled cap-shaped parts, which adopts a double-action punch composed of an outer punch and an inner punch, and cooperates with a core mold and a die to form an extrusion forming cavity. The blank is extruded to reversely extrude the blank to form a cap wall structure, and electric auxiliary heating is used to maintain the forming temperature of the blank, a cooling system is used to quickly cool the formed cap wall surface to fix the shape, and an ultrasonic vibration device is used to vibrate the cap wall surface to relieve stress. It can form an integrated thin-walled cap-shaped part structure in a short process and with high precision, realizing near-net forming with little or no cutting processing.

[0006] In order to solve the above technical problems, a technical solution adopted by the present invention is:

[0007] A thin-walled cap-shaped part integral forming device comprises a base, a column and a main press, wherein a first press is provided on the top of the base, a core mold is fixedly connected to the top output shaft end of the first press, and a water cooling circulation system is provided in the core mold;

[0008] A lower die base is fixedly provided on the column, a concave die located outside the top end of the core die is fixedly installed on the top surface of the lower die base, a first electrode plate is provided on the inner bottom side of the concave die, and an ultrasonic vibration device is provided on the top surface of the lower die base and located outside each side surface of the concave die;

[0009] The bottom output end of the main press is fixedly connected to an upper die base, the bottom surface of the upper die base is fixedly provided with an outer punch that can be movably sleeved on the inner side of the die, an air cooling circulation system is provided in the outer punch, and a second electrode plate is provided at the bottom of the outer punch;

[0010] A second press is fixedly arranged in the upper die base, and an inner punch movably sleeved on the inner side of the outer punch is fixedly connected to the bottom output end of the second press;

[0011] During the extrusion process, two electrode plates apply electricity to heat the blank, the outer punch presses the blank downward, and the inner side of the blank flows upward to form the cap wall. The inner punch and core mold rise synchronously with the cap wall, and the output end of the ultrasonic vibration device is in active contact with the outer side of the cap wall.

[0012] Furthermore, the cross-sectional outer contour shape of the core mold matches the cross-sectional contour shape of the inner wall at the bottom end of the die, the cross-sectional contour shape of the outer wall of the inner punch matches the cross-sectional contour shape of the inner wall at the bottom end of the outer punch, and the cross-sectional contour shape of the outer wall at the bottom end of the outer punch matches the cross-sectional contour shape of the inner wall at the top end of the die.

[0013] Furthermore, a forming hole is provided at the center of the bottom of the die, and the cross-sectional profile of the forming hole is located inside the cross-sectional profile of the top side wall of the die.

[0014] Furthermore, a first annular groove is provided on the top surface of the bottom wall of the die, the first electrode plate is embedded in the first annular groove, and the top surface of the first electrode plate is flush with the top surface of the bottom wall of the die.

[0015] Furthermore, a second annular groove is provided on the bottom surface of the outer convex mold, the second electrode plate is embedded in the second annular groove, and the bottom surface of the second electrode plate is flush with the bottom surface of the outer convex mold.

[0016] Furthermore, the die is made of insulating material or an insulating layer is provided on the surface of the die.

[0017] Furthermore, the ultrasonic vibration device includes a cylinder bracket fixedly arranged on the top surface of the lower mold base, a cylinder fixedly arranged on the top of the cylinder bracket, and a push-pull plate fixedly connected to the output shaft end of the cylinder. An ultrasonic vibrator is arranged on the outer surface of the push-pull plate, and a plurality of roller brackets distributed in a square matrix are arranged on the inner side surface of the push-pull plate, and a roller is rotatably installed at the end of the roller bracket.

[0018] Furthermore, a plurality of vertically arranged strip-shaped through holes are opened on the side wall of the outer punch. When the cylinder drives the push-pull plate to move horizontally, the roller bracket and the roller move through the strip-shaped through holes.

[0019] A thin-walled cap-shaped part integral forming process is also proposed, which is applied to the thin-walled cap-shaped part integral forming device as described above, and includes the following steps:

[0020] S1. Place the ring-shaped blank into the die;

[0021] S2. Start the equipment and the first press drives the core mold upward until the top surface of the core mold is flush with the top surface of the blank. The main press and the second press drive the outer punch and the inner punch respectively downward synchronously until the bottom surfaces of the outer punch and the inner punch contact the top surface of the blank.

[0022] S3, the first electrode plate and the second electrode plate are energized, and a high-frequency pulse current is passed through the blank to heat the blank to a preset forming temperature;

[0023] S4, the main press drives the outer punch and the inner punch to continue to move downward synchronously, applying a uniform axial force to the blank for a preset time to improve the density of the blank;

[0024] S5: The main press drives the outer punch to continue to extrude the blank downward. The inner side of the blank flows upward to form the cap wall. The bottom surface of the inner punch rises synchronously with the top surface of the cap wall. The first press drives the core mold to rise synchronously with the inner wall of the cap wall.

[0025] S6, the water cooling circulation system and the air cooling circulation system are operated to cool down the inner and outer sides of the extruded cap wall respectively, the ultrasonic vibration device is started, and its output end is in active contact with the outer side of the cap wall to reduce the forming stress;

[0026] S7, after the outer punch moves downward to a preset extrusion distance, the first electrode plate and the second electrode plate are powered off, the water cooling circulation system and the air cooling circulation system are shut down, the main press and the second press respectively drive the outer punch and the inner punch upward to reset, and the first press drives the core mold downward to reset;

[0027] S8. Take out the formed part.

[0028] Furthermore, in step S2, the pressure values ​​of the main press and the second press are the same, and in step S5, the pressure value of the second press is lower than the pressure value of the main press.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] The present invention adopts a double-action punch composed of an outer punch and an inner punch, which cooperates with a core mold and a die to form an extrusion forming cavity. The blank is extruded in reverse to form a cap wall structure. After the extrusion is completed, the punch and the core mold are withdrawn to take the material. The demoulding is convenient, and an integrated thin-walled cap-shaped part structure can be formed in a short process and with high precision, realizing near-net forming with little or no cutting processing, greatly improving material utilization, avoiding the welding stress concentration problem existing in welding forming, and reducing the risk of cracks.

[0031] 2. The present invention adopts a double-action punch composed of an outer punch and an inner punch. During the extrusion forming process, the core mold rises together with the extrudate, avoiding the relative movement between the core mold and the extrudate, reducing the friction and damage to the inner wall of the formed part, and reducing the extrusion force; the inner punch rises synchronously with the top of the cap wall to provide back pressure, which can ensure that the top of the cap wall is always in the same horizontal plane, making the shape more precise; the outer punch adopts a variable-caliber structure (boot-shaped punch) so that the workpiece maintains a distance from the side wall of the outer punch after fixed-diameter extrusion, and retains a certain gap between the workpiece and the top side wall of the outer punch, which serves as the action area of ​​the air cooling system and can reduce the contact friction surface between the outer wall of the cap wall and the outer punch during the extrusion process, which is conducive to the upward flow and stretching of the material.

[0032] 3. Before the extrusion forming begins, the billet of the present invention is provided with high-frequency pulse current through two electrode plates arranged above and below, which can achieve rapid heating and temperature rise to improve the plastic deformation performance of the billet, and perform temperature compensation on the billet during the entire extrusion forming process to keep the material in the same and better performance state; before the extrusion forming begins, the material is densified by applying uniform axial force, which can effectively improve the material density and reduce casting defects such as micropores and looseness.

[0033] 4. The present invention provides a water cooling circulation system in the core mold and an air cooling circulation system in the outer punch, which can quickly cool the surface of the continuously extruded material to accelerate shaping, reduce the risk of torsional deformation or wrinkle deformation of the cap wall in the subsequent height increase process, and ensure the forming accuracy.

[0034] 5. The present invention sets an ultrasonic pulse device on each side of the formed cap wall. Through the rolling contact between the roller and the outer wall of the cap wall, the outer wall is rolled and trimmed while completing high-frequency vibration to reduce the extrusion forming stress, improve the organizational properties of the cap wall, and thus improve the forming quality of the cap wall. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the three-dimensional structure of the blank and the corresponding formed part used for integral forming in the embodiment;

[0036] Figure 2 It is a schematic diagram of the three-dimensional structure of the thin-walled cap-shaped piece integrally forming device of the present invention;

[0037] Figure 3 It is a schematic cross-sectional view of the thin-walled cap-shaped piece integrally forming device of the present invention;

[0038] Figure 4 Schematic diagram of the three-dimensional structure of the concave mold described in the embodiment;

[0039] Figure 5 This is one of the three-dimensional structural diagrams of the outer punch described in the embodiment;

[0040] Figure 6 This is the second schematic diagram of the three-dimensional structure of the outer punch described in the embodiment;

[0041] Figure 7 This is one of the schematic diagrams of the three-dimensional structure of the ultrasonic vibration device described in the embodiment;

[0042] Figure 8 This is the second schematic diagram of the three-dimensional structure of the ultrasonic vibration device described in the embodiment.

[0043] In the figure: 1. base; 2. column; 3. main press; 4. first press; 5. core mold; 6. lower mold base; 7. die; 701. first ring groove; 702. inner wall forming hole; 8. upper mold base; 9. ultrasonic vibration device; 901. cylinder bracket; 902. cylinder; 903. push-pull plate; 904. ultrasonic vibrator; 905. roller bracket; 906. roller; 10. outer punch; 1001. outer wall forming hole; 1002. second ring groove; 1003. screw mounting slot; 1004. strip through hole; 11. first connecting rod; 12. second electrode plate; 13. second press; 14. inner punch; 15. second connecting rod; 16. first electrode plate; 100. blank. DETAILED DESCRIPTION

[0044] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the protection scope of the present invention.

[0045] It should be noted that when a component is referred to as being "mounted on" another component, it may be directly on the other component or there may be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a central component. When a component is considered to be "fixed to" another component, it may be directly fixed to the other component or there may be a central component.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0047] like Figure 1 As shown, this embodiment takes a 6061 aluminum billet of a rectangular annular plate and reverse extrusion to form a thin-walled cap-shaped part with a rectangular cross-sectional profile as an example to introduce in detail the specific structural composition and forming process of the one-piece forming device.

[0048] See attached Figures 2 to 8 A device for integrally forming thin-walled cap-shaped parts comprises a base 1, columns 2, and a main press 3. The columns 2 are cylindrical, and there are four of them, fixed to the four corners of the top surface of the base 1. The main press 3 utilizes a constant-speed extension hydraulic cylinder controlled by a flow control valve or servo system. The base 1, columns 2, and main press 3 can utilize existing hydraulic forming equipment and its accompanying control system. By modifying or adding the control logic programs of other working components, the motion logic control of each functional component of the device can be achieved.

[0049] A first press 4 is provided on the top of the base 1, and a core mold 5 is fixedly connected to the top output shaft end of the first press 4, and a water-cooling circulation system is provided in the core mold 5. In this embodiment, during the reverse extrusion process of the blank to form the cap wall, the core mold 5 needs to rise synchronously with the extrudate to avoid relative movement between the core mold 5 and the extrudate, thereby reducing friction and damage to the inner wall of the formed part, and reducing the extrusion force. Therefore, the first press 4 also uses a constant-speed extension hydraulic cylinder to achieve a constant-speed rise of the core mold 5 (the specific rising speed depends on the height growth rate during the cap wall forming process). The horizontal cross-sectional profile of the core mold 5 is rectangular, and its size matches the inner wall profile of the cap wall formed by reverse extrusion; and the surface of the core mold 5 is polished to improve the accuracy and surface quality of the formed shape, while reducing the extrusion friction. A water-cooling circulation channel is provided inside the core mold 5, and the inlet and outlet of the water-cooling circulation channel are connected to the external water supply system through pipelines to achieve automatic water supply control. During the extrusion forming process, cooling water is circulated in the water-cooling circulation channel to keep the core mold 5 at a low temperature, so that the surface formed after the hot metal material flows and plastically deforms can be cooled and shaped in time.

[0050] A lower die base 6 is fixedly mounted on the columns 2. The lower die base 6 is a rectangular metal plate with its four corners mounted on the four columns 2 and secured to the columns 2 via bolts or pins. A rectangular through-hole is defined at the center of the lower die base 6, allowing the top end of the core die 5 to move through. In this embodiment, the dimensions of the rectangular through-hole match the cross-sectional dimensions of the core die 5. When the first press 4 drives the core die 5 to its lowest position, the top end of the core die 5 remains within the rectangular through-hole, thus guiding the vertical movement of the core die 5.

[0051] A die 7 located on the outside of the top end of the core mold 5 is fixedly mounted on the top surface of the lower mold base 6 by screw connection. The groove 7 is a rectangular trough structure with an open top, and an inner wall forming hole 702 (rectangular through hole) is provided on its bottom wall. The horizontal distances between each inner wall of the inner wall forming hole 702 and the top inner wall of each corresponding side of the groove 7 are equal, that is, the width of each side of the bottom wall is the same. The outer surface of the core mold 5 is slidably matched with each side of the inner wall forming hole 702, that is, the outer contour shape of the cross section of the core mold 5 matches the contour shape of the cross section of the inner wall forming hole 702. The blank to be formed is located on the top surface of the bottom wall of the groove 7 and on the outside of the top opening edge of the rectangular through hole, so that the top end of the core mold 5 is inserted from bottom to top into the internal hollow area of ​​the blank.

[0052] The first electrode plate 16 is provided on the inner bottom side of the die 7. Figure 4 As shown, a first annular groove 701 is formed on the top surface of the bottom wall of the die 7. The first electrode plate 16 is embedded in the first annular groove 7, and the top surface of the first electrode plate 16 is flush with the top surface of the bottom wall of the die 7, together forming the bottom surface of the forming cavity of the annular blank 100. In this way, when the blank 100 to be formed is placed in the die 7, the bottom surface of the blank 100 is in contact with both the top surface of the bottom wall of the groove 7 and the top surface of the first electrode plate 16. Through the first electrode plate 16, one output electrode of an external high-frequency pulse power supply can be introduced to the bottom of the blank 100.

[0053] The upper die base 8 is fixedly connected to the bottom output end of the main press 3. The upper die base 8 is a rectangular metal plate, and its four corners are movably connected to the outside of the column 2. The main press 3 drives the upper die base 8 to move vertically, and the column 2 guides the vertical movement of the upper die base 8. The four corners of the bottom surface of the upper die base 8 are fixedly connected to the outer punch 10 through four first connecting rods 11. Figure 5 and Figure 6As shown, the outer male mold 10 is a rectangular trough structure with an open top. The cross-sectional profile of its bottom outer wall matches the cross-sectional profile of the inner wall at the top of the female mold 7. The bottom wall is provided with an outer wall forming hole 1001 (a rectangular through-hole). Each side surface of the outer wall forming hole 1001 is located outside each side surface of the corresponding side surface of the inner wall forming hole 702. The horizontal spacing between each side surface is the thickness of each side wall of the extruded cap wall (2.5 mm in this embodiment). In this embodiment, the horizontal spacing between each side surface of the outer wall forming hole 1001 and the inner wall forming hole 702 is preferably the same, that is, the wall thickness of each side wall of the extruded cap wall is the same. The outer punch 10 adopts a variable-caliber structure (shoe-shaped punch) so that the workpiece maintains a certain distance from the side wall of the outer punch 10 (the side of the outer wall forming hole 1001) after the workpiece is extruded with a fixed diameter, and a certain gap is retained between the top side wall of the outer punch 10, which serves as the action area of ​​the air cooling system and reduces the contact friction surface between the outer wall of the cap wall and the outer punch 10 during the extrusion process.

[0054] The bottom of the outer punch 10 is provided with a second electrode plate 12. Specifically, a second annular groove 1002 is provided on the bottom surface of the outer punch 10. The second electrode plate 12 is embedded in the second annular groove 1002, and the bottom surface of the second electrode plate 12 is flush with the bottom surface of the outer punch 10, together forming the top surface of the forming cavity of the ring-shaped blank 100. A bolt through hole is provided on the bottom edge of the outer punch 10, and a screw mounting groove 1003 is provided on the outer wall that passes through the top of the bolt through hole. A threaded hole corresponding to the bolt through hole is provided on the top surface of the second electrode plate 12. The screw is installed in the bolt through hole through the screw mounting groove 1003 and is threadedly connected to the threaded hole, so that the second electrode plate 12 is fixedly connected to the bottom of the outer punch 10.

[0055] During the forming process, the main press 3 drives the upper die holder 8 downward, so that the outer punch 10 is vertically inserted into the die 7. The outer wall of the outer punch 10 slides and fits with the inner wall of the die 7. The top surface of the blank 100 contacts the bottom surface of the outer punch 10 and the bottom surface of the second electrode plate 12 at the same time. At this time, the bottom surface of the outer punch 10 and the second electrode plate 12, the top inner wall and bottom wall top surface of the die 7, and the wall surface of the core mold 5 form an extrusion cavity. The annular area between the inner wall of the outer punch 10 and the wall surface of the core mold 5 serves as a forming channel for reverse extrusion after the material is extruded. The second electrode plate 12 can be used to introduce the other output electrode of the external high-frequency pulse power supply to the bottom of the blank 100, thereby cooperating with the first electrode plate 16 to continuously power the outer portion of the blank 100, so that the blank 100 is quickly heated to the preset forming temperature and continuously compensates for energy loss to maintain it within the appropriate forming temperature range. After the blank 100 reaches the forming temperature, the outer punch 10 continues to descend, applying a forming extrusion force to the blank 100. The material of the blank 100 flows and deforms under pressure, continuously extending upward from the forming channel to form an annular cap wall. Preferably, the die 7 is made of an insulating material or provided with an insulating layer on its surface, so that the first electrode plate 16 and the second electrode plate 12 are insulated from each other on the upper and lower sides of the blank 100.

[0056] An air-cooling circulation system is installed within the outer punch 10. The inlet and outlet of the air-cooling circulation channel are connected to an external air supply system via pipelines, enabling automatic air supply control. During the extrusion process, cooling gas circulates through the air-cooling circulation channel and blows onto the outer surface of the cap wall formed by reverse extrusion, cooling the outer surface and allowing the surface formed after the hot metal material flows and plastically deforms to cool and set in a timely manner.

[0057] A second press 13 is fixedly installed in the upper die base 8, and the bottom output end of the second press 13 is fixedly connected to an inner punch 14 movably sleeved on the inner side of the outer punch 10 through four second connecting rods 15. In this embodiment, during the reverse extrusion process of the blank to form the cap wall, the inner punch 14 needs to rise synchronously with the extrudate to apply back pressure to the top of the cap wall, thereby ensuring that the top of the extrudate is in the same horizontal plane and reducing the risk of distortion of the formed part. Therefore, the second press 13 also adopts a constant speed extension hydraulic cylinder to achieve a constant speed rise of the inner punch 14 (the specific rising speed depends on the height growth rate during the cap wall forming process). The inner punch 14 is a rectangular cylindrical structure with upper and lower openings, and the cross-sectional profile shape of its outer wall matches the cross-sectional profile shape of the outer wall forming hole 1001, that is, the outer wall of the inner punch 14 slides and fits with the bottom inner wall of the outer punch 10. During the heating process of the blank 100, the bottom surface of the inner punch 14 is flush with the bottom surface of the outer punch 10, thereby blocking the forming channel of the reverse extrusion forming of the cap wall, and thus forming a double-action punch structure together with the outer punch 10, applying a certain axial pressure to the heated blank 100, thereby improving the material density and reducing casting defects such as micropores and looseness.

[0058] The top surface of the lower die base 6 is provided with ultrasonic vibration devices 9 located on the outside of each side of the die 7. In this embodiment, the blank 100 is a rectangular structure, and the extruded cap wall is also a rectangular structure, so a set of ultrasonic vibration devices 9 is provided on each side, for a total of four sets. Figure 7 and Figure 8 As shown, the ultrasonic vibration device 9 includes a cylinder bracket 901 fixedly mounted on the top surface of the lower die base 6, a cylinder 902 fixedly mounted on the top of the cylinder bracket 901, and a push-pull plate 903 fixedly connected to the output shaft end of the cylinder 902. The outer surface of the push-pull plate 903 is provided with an ultrasonic vibrator 904, and the inner surface of the push-pull plate 903 is provided with a plurality of roller brackets 905 distributed in a square matrix. The ends of the roller brackets 905 are rotatably mounted with rollers 906. During the extrusion forming process, the cylinder 902 drives the push-pull plate 903 to move horizontally toward the formed cap wall, causing the cylindrical surface of the roller 906 to roll in contact with the outer surface of the cap wall, exerting a supporting force on the outer side of the cap wall and cooperating with the wall surface of the core mold 5 to prevent the cap wall from wrinkling and deformation under the back pressure of the inner punch 14. As the cap wall continues to grow upward, the roller 906 rolls relative to the surface of the cap wall, which can simultaneously perform a surface finishing treatment on the cap wall during the air cooling process, thereby improving the surface forming quality. At the same time, the ultrasonic vibrator 904 continues to work, and performs high-frequency ultrasonic vibration on the outer surface of the cap wall through the roller 906 to reduce the processing force and residual stress, thereby improving the surface quality.

[0059] Since the movement of the roller 906 is horizontal and the movement of the outer punch 10 is vertical, a number of vertically arranged strip through holes 1004 are opened on the side wall of the outer punch 10, and a notch located outside the strip through hole 1004 is opened on the top of the side wall of the die 7. In the process of the cylinder 902 driving the push-pull plate 903 to move horizontally, the roller bracket 905 and the roller 906 move through the notch and the strip through hole 1044, so that the roller 906 reaches the outer side surface of the cap wall.

[0060] A thin-walled cap-shaped part integral forming process, applied to the aforementioned thin-walled cap-shaped part integral forming device, comprises the following steps:

[0061] S1. The annular blank 100 is placed in the die. In the initial state of the equipment, the top of the core mold 5 is located in the lower die base 6, the outer punch 10 and the inner punch 14 are both suspended above the top of the die 7, and the innermost end of the cylindrical surface of the roller 906 is located on the outside of the inner wall of the die 7. According to the weight of the blank 100 and the arrangement of the production cycle, manual placement or automatic placement by a robot can be selected. The outer dimensions of the blank 100 are slightly smaller than the inner wall cross-sectional dimensions of the die 7, and the inner hole dimensions are slightly larger than the cross-sectional dimensions of the core mold 5. The widths of the various sides of the ring are as similar as possible, so that the blank 100 can fall smoothly vertically into the die 7, and the top of the core mold 5 can rise smoothly into the inner hole of the blank 100.

[0062] S2. Start the equipment. The first press 4 drives the core die 5 upward until the top surface of the core die 5 is flush with the top surface of the blank 100. At this point, the top of the core die 5 is located in the inner hole of the blank 100. The main press 3 and the second press 13 respectively drive the outer punch 10 and the inner punch 14 downward synchronously until the bottom surfaces of the outer punch 10 and the inner punch 14 contact the top surface of the blank 100. At this point, the output shaft of the second press 13 is in the maximum extended state, and the output pressure of the second press 13 is the same as that of the main press 3 to keep the bottom surface of the inner punch 14 flush with the bottom surface of the outer punch 10.

[0063] S3, the first electrode plate 16 and the second electrode plate 12 are energized, and a high-frequency pulse current is passed through the blank 100 to heat the blank 100 to a preset forming temperature. The specific preset forming temperature is set according to the optimal forming temperature corresponding to the specific material of the blank 100, and can be monitored by a thermocouple thermometer or a thermal imager. During the continuous extrusion forming process of the blank 100, its own heat will be partially dissipated. In order to maintain the same plasticity of the blank 100, the blank 100 needs to be energy compensated; and after the blank 100 is continuously reversed to form the cap wall, the thickness of the bottom material will gradually decrease, so the current density passed through the first electrode plate 16 and the second electrode plate 12 needs to be reduced accordingly. The specific current density change curve can be pre-calculated based on the energy dissipation rate of the blank 100, and then the pulse current output of the pulse power supply is controlled by the current density change curve.

[0064] S4: The main press 3 drives the outer punch 10 and the inner punch 14 to continue to move downward synchronously, applying a uniform axial force to the blank 100 for a predetermined period of time to improve the density of the blank. The specific duration of the pressure is set according to the specific material of the blank 100 and the output force of the main press 3, and is preferably set so that the blank 100 reaches the predetermined density.

[0065] S5: The main press 3 drives the outer punch 10 to continue to extrude the blank 100 downward. The inner side of the blank 100 flows upward to form the cap wall. The bottom surface of the inner punch 14 rises synchronously with the top surface of the cap wall. The first press 4 drives the core mold 5 to rise synchronously with the inner wall of the cap wall. During this process, the pressure value of the second press 13 is lower than that of the main press 3. The bottom surface of the inner punch 14 can provide back pressure for the top of the cap wall, keeping the top surface of the cap wall flat. The outer wall of the core mold 5 is used to form the inner wall surface of the cap wall, and the inner wall forming hole 702 is used to form the outer wall surface of the cap wall.

[0066] S6. The water cooling circulation system and the air cooling circulation system work to cool down the inner and outer sides of the extruded cap wall respectively. The outer part of the blank 100 flows continuously inward under the continuous extrusion action, and then continues to flow and extend upward. The core mold 5 under water cooling can maintain a low temperature state, thereby quickly cooling the inner side wall of the newly formed cap wall to shape it. The continuously blown in cold air can continuously and quickly cool the outer side wall of the cap wall to shape it.

[0067] The ultrasonic vibration device 9 is started, and the cylinder 902 drives the roller 906 to move horizontally until it is in active contact with the outer side surface of the cap wall. In the process of continuous increase of the cap wall, its outer wall surface rolls in contact with the rollers 906 of each layer from bottom to top. The rollers 906 continuously roll the outer wall surface of the cap wall and vibrate the outer wall surface at high frequency, thereby reducing the forming stress and improving the forming quality of the outer wall surface.

[0068] S7. After the outer punch 10 descends to the preset extrusion distance, the first electrode plate 16 and the second electrode plate 12 are powered off, the water cooling circulation system and the air cooling circulation system are closed, the main press 3 and the second press 13 respectively drive the outer punch 10 and the inner punch 14 upward to reset, and the first press 4 drives the core mold 5 downward to reset.

[0069] S8, take out the formed part, and complete the entire extrusion forming process.

[0070] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0071] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A thin-walled hat-shaped integral forming device, comprising a base, a column and a main press, characterized in that: A first press is provided on the top of the base, a core mold is fixedly connected to the top output shaft end of the first press, and a water cooling circulation system is provided in the core mold; A lower die base is fixedly provided on the column, a concave die located outside the top end of the core die is fixedly installed on the top surface of the lower die base, a first electrode plate is provided on the inner bottom side of the concave die, and an ultrasonic vibration device is provided on the top surface of the lower die base and located outside each side surface of the concave die; The bottom output end of the main press is fixedly connected to an upper die base, the bottom surface of the upper die base is fixedly provided with an outer punch that can be movably sleeved on the inner side of the die, an air cooling circulation system is provided in the outer punch, and a second electrode plate is provided at the bottom of the outer punch; A second press is fixedly arranged in the upper die base, and an inner punch movably sleeved on the inner side of the outer punch is fixedly connected to the bottom output end of the second press; During the extrusion process, two electrode plates are energized to heat the outer part of the blank, the outer punch presses the blank downward, and the inner part of the blank flows upward to form the cap wall. The water cooling circulation system and the air cooling circulation system cool the inner and outer wall surfaces of the cap wall at the same time as the cap wall gradually increases, and the inner punch and the core mold rise synchronously with the cap wall. The output end of the ultrasonic vibration device rolls in contact with the outer side of the cap wall, synchronously shaping the cap wall surface during the cooling process and reducing the forming stress.

2. The thin-walled cap-shaped piece integrally forming device according to claim 1, characterized in that: The cross-sectional outer contour shape of the core mold matches the cross-sectional contour shape of the inner wall at the bottom end of the die, the cross-sectional contour shape of the outer wall of the inner punch matches the cross-sectional contour shape of the inner wall at the bottom end of the outer punch, and the cross-sectional contour shape of the outer wall at the bottom end of the outer punch matches the cross-sectional contour shape of the inner wall at the top end of the die.

3. The thin-walled hat-shaped piece integrally forming device according to claim 2, characterized in that: A forming hole is opened at the center of the bottom of the die, and the cross-sectional profile of the forming hole is located inside the cross-sectional profile of the top side wall of the die.

4. The thin-walled cap-shaped piece integrally forming device according to claim 2, characterized in that: A first annular groove is provided on the top surface of the bottom wall of the die. The first electrode plate is embedded in the first annular groove, and the top surface of the first electrode plate is flush with the top surface of the bottom wall of the die.

5. The thin-walled cap-shaped piece integrally forming device according to claim 2, characterized in that: A second annular groove is provided on the bottom surface of the outer convex mold. The second electrode plate is embedded in the second annular groove, and the bottom surface of the second electrode plate is flush with the bottom surface of the outer convex mold.

6. The thin-walled cap-shaped piece integrally forming device according to claim 4 or 5, characterized in that: The concave mold is made of insulating material or an insulating layer is provided on the surface of the concave mold.

7. The thin-walled hat-shaped piece integrally forming device according to any one of claims 1 to 5, characterized in that: The ultrasonic vibration device includes a cylinder bracket fixedly arranged on the top surface of the lower mold base, a cylinder fixedly arranged on the top of the cylinder bracket, and a push-pull plate fixedly connected to the output shaft end of the cylinder. An ultrasonic vibrator is arranged on the outer surface of the push-pull plate, and a plurality of roller brackets distributed in a square matrix are arranged on the inner side surface of the push-pull plate. A roller is rotatably installed at the end of the roller bracket.

8. The thin-walled hat-shaped piece integrally forming device according to claim 7, characterized in that: A plurality of vertically arranged strip-shaped through holes are provided on the side wall of the outer punch. When the cylinder drives the push-pull plate to move horizontally, the roller bracket and the roller move through the strip-shaped through holes.

9. A thin-walled cap-shaped part integral forming process, applied to the thin-walled cap-shaped part integral forming device according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Place the ring-shaped blank into the die; S2. Start the equipment, the core mold moves upward until its top surface is flush with the top surface of the blank, and the outer punch and the inner punch move downward synchronously until their bottom surfaces contact the top surface of the blank; S3, energizing the first electrode plate and the second electrode plate to heat the blank to a preset forming temperature; S4, the outer punch and the inner punch continue to move downward synchronously, applying a uniform axial force to the blank for a preset time; S5, the outer punch continues to squeeze the blank downward, the inner side of the blank flows upward to form the cap wall, and the inner punch and the core mold rise synchronously with the cap wall; S6, the water cooling circulation system and the air cooling circulation system work to cool the extruded cap wall, the ultrasonic vibration device is started, and its output end is in active contact with the outer surface of the cap wall to reduce the forming stress; S7, after the outer punch moves downward to a preset extrusion distance, the first electrode plate and the second electrode plate are powered off, the water cooling circulation system and the air cooling circulation system are closed, the outer punch and the inner punch move upward to reset, and the core mold moves downward to reset; S8. Take out the formed part.

10. The thin-walled cap-shaped part integral forming process according to claim 9, characterized in that: In step S2, the pressure values ​​of the main press and the second press are the same. In step S5, the pressure value of the second press is lower than the pressure value of the main press.

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