Stretch bending die and design method thereof

Abstract

The invention discloses a stretch bending die and a design method thereof, and relates to the technical field of profile stretch bending. The stretch bending die comprises an arc-shaped steel plate and an inner core, and the arc-shaped steel plate is provided with an outer arc surface with a preset curvature radius; the inner core is provided with an inner arc side with the same preset curvature radius as the outer arc face and an outer arc side opposite to the inner arc side, the inner arc side is fixed to the outer arc face, and the outer arc side is used for bending a profile to be machined. The design method comprises the steps of manufacturing the arc-shaped steel plate, manufacturing the inner core and welding the inner core on the outer arc surface of the arc-shaped steel plate. The stretch bending die has the advantages of being simple in structure and low in manufacturing cost, and polyurethane filler is omitted. On one hand, the angle change of the sectional material caused by insufficient rigidity of polyurethane is avoided, so that the forming precision of the sectional material is improved; and on the other hand, the preparation work of polyurethane filling is omitted, the preparation time before forming is shortened, and then the forming efficiency is improved. The method is simple and convenient to operate, easy to implement and low in manufacturing cost, and the production cost can be effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of profile bending, and in particular to a bending die and a design method thereof. Background Art

[0002] Profile bending is a process that applies tensile force on a bending machine and combines it with a bending die to plastically deform metal profiles (such as aluminum alloys, steel, etc.) and bend them into the desired shape. This technology is widely used in aerospace, rail transportation, civil automobiles, construction and other fields.

[0003] For high-precision products such as aerospace, integral tires are usually used for stretch bending. Integral tires have high strength and precision, can achieve high molding efficiency, and help meet the requirements for high-precision products. However, the manufacturing cost of integral tires is high, and the processing process relies on large equipment, which usually needs to be completed through integral machining, resulting in increased production costs and longer construction periods.

[0004] In the civil automobile and construction industries, arc plate bending dies with simple structures are usually used. These dies are low in cost, but they need to be filled with polyurethane during the profile bending process, resulting in low profile forming efficiency and poor forming accuracy. Although this mold has advantages in cost, it has obvious shortcomings in forming efficiency and accuracy.

[0005] In summary, it is difficult for existing stretch-bending dies to achieve a good balance between cost, forming efficiency and precision. Therefore, there is an urgent need for a stretch-bending die that can reduce manufacturing costs and improve profile forming efficiency and precision. Summary of the invention

[0006] In order to solve the above technical problems, the purpose of the present invention is to provide a stretch-bending die and a design method thereof, aiming to reduce manufacturing costs while improving profile forming efficiency and precision.

[0007] The technical solution provided by the present invention is as follows: A stretch bending die, comprising: A curved steel plate having an outer curved surface with a preset radius of curvature; The inner core has an inner arc side with the same preset curvature radius as the outer arc surface and an outer arc side arranged opposite to the inner arc side, the inner arc side is fixedly arranged on the outer arc surface, and the outer arc side is used for bending the profile to be processed.

[0008] Furthermore, the inner core comprises: A first arc-shaped support plate, the inner side of which is fixedly arranged on the outer arc surface; A second arc-shaped support plate, the inner side of which is fixedly disposed on the outer arc surface and is disposed parallel to the first arc-shaped support plate; An arc-shaped connecting plate, one side of which is connected to the outer side of the first arc-shaped supporting plate, and the other side of which is connected to the outer side of the second arc-shaped supporting plate; The inner sides of the first arc-shaped support plate and the second support plate are the inner arc sides of the inner core, and the outer shape surface of the arc-shaped connecting plate is the outer arc side of the inner core.

[0009] Furthermore, the outer arc surface, the first arc-shaped support plate, the arc-shaped connecting plate and the second arc-shaped support plate are jointly arranged to form a receiving cavity, and a supporting block is arranged in the receiving cavity.

[0010] Furthermore, the stretch-bending die also includes a platen side-pushing device for fixing the arc-shaped steel plate on a working platform, and the platen side-pushing device includes: A pressing plate abutting against the top of the arc-shaped steel plate; The side push piece is used to adjust the arc-shaped steel plate so that its outer arc surface reaches a preset curvature radius.

[0011] Furthermore, the stretch-bending die also includes a flanging baffle plate, which is movably arranged on the top of the profile to be processed.

[0012] Furthermore, the stretch-bending die also includes reinforcing ribs, which are arranged on the outer curved surface of the curved steel plate and are located above the flanging baffle.

[0013] On the other hand, the present invention further provides a method for designing a stretch-bending die, wherein the stretch-bending die is the stretch-bending die described in any one of the above embodiments, and the design method comprises the following steps: Making curved steel plates: CNC cutting is used to obtain steel plates of preset sizes, and the steel plates are rolled and bent to a preset curvature radius; Making the inner core: making a first arc-shaped support plate, an arc-shaped connecting plate and a second arc-shaped support plate, and welding them in sequence to form a C-shaped structure; Welding: Weld the open end of the C-shaped structure onto the outer arc surface of the arc-shaped steel plate.

[0014] Furthermore, welding the open end of the C-shaped structure to the outer curved surface of the curved steel plate specifically comprises the following steps: Fixing the curved steel plate: placing the curved steel plate on a working platform, adjusting the curved steel plate by a pressing plate side pushing device to make it reach a preset curvature radius, and then fixing the curved steel plate on the working platform; Welding the inner core: Extend the arm of the profile bending machine to 180°, locate the center of the arm using a laser level, mark the curved steel plate, locate the inner core according to the position of the laser level, and weld it to the curved steel plate.

[0015] Furthermore, the steps of manufacturing a first arc-shaped support plate, an arc-shaped connecting plate, and a second arc-shaped support plate, and welding them in sequence to form a C-shaped structure specifically include the following steps: The first arc support plate and the second arc support plate are made of a plurality of planar arc plates respectively, wherein the inner arc radius of the planar arc plate is the same as the preset curvature radius of the outer arc surface of the arc steel plate; Grinding welding grooves: Grinding welding grooves on the outer sides of the first arc-shaped support plate and the second arc-shaped support plate respectively; Making the arc-shaped connecting plate: CNC cutting to obtain a steel plate of a preset size, rolling the steel plate after cutting to bend it to a preset curvature radius, the preset curvature radius of the inner arc surface of the arc-shaped connecting plate is the same as the outer arc radius of the plane arc plate; Argon arc welding: Place the first arc-shaped support plate on the platform, and weld its outer side to one side of the arc-shaped connecting plate using the outer side as the reference plane. After welding, weld the outer side of the second arc-shaped support plate to the other side of the arc-shaped connecting plate.

[0016] Furthermore, the step of making the inner core also includes the following steps: Placing a support block: placing the support block in the C-shaped structure; Grinding fillet: Grinding fillet at the contact position between the inner core and the profile to be processed.

[0017] Compared with the prior art, the bending die and design method thereof provided by the embodiment of the present invention have at least the following technical effects: The bending die includes an arc-shaped steel plate and an inner core. The arc-shaped steel plate has an outer arc surface with a preset curvature radius. The inner core has an inner arc side with the same preset curvature radius as the outer arc surface and an outer arc side arranged opposite to the inner arc side. The inner arc side is fixed on the outer arc surface, and the outer arc side is used to bend the profile to be processed. The bending die has the characteristics of simple structure and low manufacturing cost, and eliminates the use of polyurethane fillers. On the one hand, it avoids the change of profile angle caused by insufficient rigidity of polyurethane, thereby improving the precision of profile forming; on the other hand, it saves the preparation work of polyurethane filling, reduces the preparation time before forming, and thus improves the forming efficiency.

[0018] In addition, the design method of the bending die obtains a steel plate of a preset size by CNC blanking, and then rolls the blanked steel plate to bend it to a preset radius of curvature, thereby obtaining a curved steel plate. Then, the inner core is formed by sequentially welding the first curved support plate, the curved connecting plate, and the second curved support plate. Finally, the inner core is fixed on the outer curved surface of the curved steel plate by welding to complete the production of the bending die. The method is simple to operate, easy to implement, and has a low manufacturing cost, which can effectively reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a schematic diagram of the overall structure of the stretch bending die; Figure 2 for Figure 1 A schematic diagram of a top view structure; Figure 3 for Figure 1 The structural diagram at A in the middle; Figure 4 It is a structural schematic diagram of the profile to be processed; Figure 5 It is a schematic diagram of the cross-sectional structure of the profile to be processed; Figure 6 A flowchart of the design method is shown in FIG. Figure 7 for Figure 6 Schematic diagram of the process of step S3; Figure 8 for Figure 6 Schematic diagram of the process of step S2 in FIG.

[0021] Reference numerals: 1. Arc-shaped steel plate; 2. Inner core; 21. First arc-shaped support plate; 22. Second arc-shaped support plate; 23. Arc-shaped connecting plate; 24. Accommodating cavity; 3. Profile to be processed; 31. First part; 32. Second part; 4. Working platform; 5. Pressing plate side thrust device; 51. Pressing plate; 52. Side thrust piece; 6. Flanged baffle plate; 7. Reinforcing ribs. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that when an element is referred to as being "fixed on" or "set on" another element, it can be directly on the other element or indirectly set on the other element; when an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0024] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0025] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" and "several" is two or more, unless otherwise clearly and specifically defined.

[0026] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with this technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantive technical significance. Any structural modification, change in proportion or adjustment of size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical contents disclosed by the present invention.

[0027] Profile bending is widely used in the aerospace field. Specifically, in aircraft manufacturing, profile bending is mainly used to produce key components such as frame ribs, front and rear fuselage sections, and engine nacelles. These components not only affect the aerodynamic shape of the aircraft, but also have extremely high requirements for shape accuracy. In rocket manufacturing, the profile bending process is used to manufacture key components such as the upper and lower end frames of the cabin, transition rings, etc. These components are subject to greater pressure and have extremely strict precision requirements. Especially when they are connected into a full circle by bolts, assembly accuracy is particularly important.

[0028] In the field of civilian automobile manufacturing, profile bending technology is widely used to process hollow aluminum profile bending parts such as body structures and bumpers. Through this process, the weight of the body can be effectively reduced while maintaining the impact strength of the body, thereby reducing the cost of using the vehicle.

[0029] The profile bending process in different fields is different, which is mainly reflected in the forming accuracy, efficiency and cost.

[0030] In the field of aerospace, products have high requirements for forming accuracy and finishing efficiency after quenching, so the process flow is usually: cutting → pre-bending → quenching → additional bending → finishing. The forming of parts in this field generally adopts an integral tire, and the radius of curvature of the integral tire is usually coordinated according to the radius of curvature of the part. Due to the rebound phenomenon of sheet metal parts after forming, there is a deviation between the formed radius of curvature and the design drawing. At the same time, the deformation of the parts after heat treatment is large, so it is necessary to use the additional bending process to reduce the rebound, reduce the bending of the parts, and improve the flatness and surface quality. The integral tire has high strength and precision, can achieve high forming efficiency, and help meet the requirements for high-precision products. However, the manufacturing cost of the integral tire is high, and the processing process relies on large equipment, which usually needs to be completed through overall machining, resulting in increased production costs and a long construction period.

[0031] In the fields of civil automobiles and construction, products pay more attention to cost control, so their process flow is usually: cutting → quenching → filling → bending → finishing. The parts in this field are formed using arc plate bending dies and polyurethane fillers. The radius of curvature of the arc plate bending dies is generally coordinated according to the radius of curvature of the parts. However, due to the low rigidity of polyurethane, it is easy to cause the profile angle to change during the forming process, thereby affecting the bending accuracy. In addition, since polyurethane needs to be filled during the bending process of the profile, the profile forming efficiency is low.

[0032] In summary, based on considerations of the manufacturing cost of a stretch-bending die, and the efficiency and precision of profile forming, the present invention provides a stretch-bending die and a design method thereof, aiming to reduce the manufacturing cost while improving the efficiency and precision of profile forming.

[0033] Please refer to the attached Figure 1 To Attachment Figure 3 As shown, an embodiment of the present invention provides a stretch-bending die, comprising a curved steel plate 1 and an inner core 2, wherein the curved steel plate 1 has an outer curved surface with a preset radius of curvature; the inner core 2 has an inner curved side with the same preset radius of curvature as the outer curved surface and an outer curved side arranged opposite to the inner curved side, wherein the inner curved side is fixedly arranged on the outer curved surface, and the outer curved side is used to bend a profile 3 to be processed. The inner curved side of the inner core 2 has the same preset radius of curvature as the outer curved surface of the curved steel plate 1, thereby ensuring that the inner curved side can fit tightly with the outer curved surface of the curved steel plate 1. In actual use, the profile 3 to be processed is placed on the outer curved side of the inner core 2, and then by applying a tensile force, the profile 3 to be processed is gradually bent along the outer curved side of the inner core 2, and finally formed.

[0034] In this embodiment, the bending die includes an arc-shaped steel plate 1 and an inner core 2. The arc-shaped steel plate 1 has an outer arc surface with a preset curvature radius; the inner core 2 has an inner arc side with the same preset curvature radius as the outer arc surface and an outer arc side arranged opposite to the inner arc side. The inner arc side is fixed on the outer arc surface, and the outer arc side is used to bend the profile 3 to be processed. The bending die has the characteristics of simple structure and low manufacturing cost, and eliminates the use of polyurethane fillers. On the one hand, it avoids the change of profile angle caused by insufficient rigidity of polyurethane, thereby improving the precision of profile forming; on the other hand, it saves the preparation work of polyurethane filling, reduces the preparation time before forming, and thus improves the forming efficiency.

[0035] In some optional embodiments, the height of the inner core 2 is less than the height of the arc-shaped steel plate 1, the length of the inner core 2 is equal to the length of the arc-shaped steel plate 1, and the inner arc side of the inner core 2 is fixedly set at the middle position in the height direction of the outer arc surface of the arc-shaped steel plate 1.

[0036] In some optional embodiments, the inner core 2 includes a first arc-shaped support plate 21, a second arc-shaped support plate 22 and an arc-shaped connecting plate 23. The inner side of the first arc-shaped support plate 21 is fixedly arranged on the outer arc surface; the inner side of the second arc-shaped support plate 22 is fixedly arranged on the outer arc surface and is arranged parallel to the first arc-shaped support plate 21; one side of the arc-shaped connecting plate 23 is connected to the outer side of the first arc-shaped support plate 21, and the other side is connected to the outer side of the second arc-shaped support plate 22; wherein, the inner sides of the first arc-shaped support plate 21 and the second support plate are the inner arc side of the inner core 2, and the outer shape surface of the arc-shaped connecting plate 23 is the outer arc side of the inner core 2.

[0037] In some optional embodiments, the outer arc surface, the first arc-shaped support plate 21 , the arc-shaped connecting plate 23 and the second arc-shaped support plate 22 are jointly arranged to form a receiving cavity 24 , and a support block is arranged in the receiving cavity 24 .

[0038] In some optional embodiments, outer sides of the first arc-shaped support plate 21 and the second arc-shaped support plate 22 are respectively connected to opposite sides of the arc-shaped connecting plate 23 by welding; and outer sides of the first arc-shaped support plate 21 and the second arc-shaped support plate 22 are both provided with welding grooves.

[0039] In some optional embodiments, the first arc-shaped support plate 21 , the arc-shaped connecting plate 23 , and the second arc-shaped support plate 22 are welded in sequence to form a C-shaped structure, and the C-shaped structure and the outer arc surface together form a receiving cavity 24 .

[0040] In some optional embodiments, the stretch-bending die further includes a pressure plate side-thrust device 5, which is used to fix the curved steel plate 1 on the working platform 4, and the pressure plate side-thrust device 5 includes a pressure plate 51 and a side-thrust member 52. The pressure plate 51 abuts against the top of the curved steel plate 1; the side-thrust member 52 is used to adjust the curved steel plate 1 so that the outer arc surface of the curved steel plate 1 reaches a preset curvature radius. Specifically, an adjustment hole is provided on the pressure plate 51, and a bolt for tightening the position of the pressure plate 51 is installed in the adjustment hole. By adjusting the bolt, the position of the pressure plate 51 can be flexibly adjusted according to the preset curvature radius requirement of the outer arc surface of the curved steel plate 1, thereby ensuring that the pressure plate 51 can be tightly abutted against the top of the curved steel plate 1 with different curvature radii. The side-thrust member 52 includes a thrust surface and a driving member, wherein the thrust surface is used to abut against the inner arc surface of the curved steel plate 1. The driving member is used to push the thrust surface to move. The driving member may adopt an adjustable bolt structure, and the movement of the thrust surface may be controlled by adjusting the position and pressure of the bolt, so that the outer arc surface of the arc-shaped steel plate 1 reaches a preset curvature radius.

[0041] In some optional embodiments, there are multiple platen side thrust devices 5. For example, there are 10 platen side thrust devices 5, and the interval between two adjacent platen side thrust devices 5 is 500 mm.

[0042] Please refer to the attached Figure 4 and attached Figure 5 As shown, in some optional embodiments, the bending die is used to process the profile 3 to be processed with an L-shaped cross section, and the profile 3 to be processed includes a first part 31 and a second part 32 arranged vertically, the first part 31 is placed on the outside of the arc-shaped connecting plate 23, and the second part 32 is placed above the first arc-shaped support plate 21. In a specific embodiment, the length of the first part 31 in the vertical direction is 96mm, and the thickness is 10mm, and the length of the second part 32 in the horizontal direction is 100mm, and the thickness is 6mm. The profile 3 to be processed can be an aluminum alloy profile, and the overall length is consistent with the arc-shaped steel plate 1 and the inner core 2.

[0043] It should be further explained that the stretch-bending die also includes a flanging baffle 6, which is used to be movably set on the top of the profile 3 to be processed. Among them, the number of flanging baffles 6 is multiple (for example, 7), and the inner arc radius corresponding to each flanging baffle 6 is the same as the preset curvature radius of the outer arc surface of the arc-shaped steel plate 1 (for example, R2134mm). Specifically, when the profile 3 to be processed is wrapped and bent along the stretch-bending die, the flanging baffle 6 will be gradually placed on the top of the profile 3 to be processed while the profile 3 to be processed is bent, playing an effective limiting role, thereby reducing the warping phenomenon of the profile 3 to be processed during the bending process. The flanging baffle 6 is movably set on the top of the profile 3 to be processed. On the one hand, this design is easy to install, and on the other hand, after the profile is bent, the flanging baffle 6 can be quickly removed so that the profile can be demolded smoothly.

[0044] In a specific embodiment, a laser cutting machine is used to perform CNC cutting of a 10 mm thick No. 45 steel plate to produce 7 flanged baffles 6, each of which has an outer arc size of R2306 mm and an inner arc size of R2134 mm. It should be further explained that the lower surface of the flanged baffle 6 is polished to be smooth and flat. At the same time, the outer arc portion of the flanged baffle 6 is polished to form a chamfer, and the size of the chamfer may be 6 mm×3 mm, but is not limited thereto.

[0045] In some optional embodiments, the stretch bending die further includes a positioning block, which is arranged on the first arc-shaped support plate 21 and is used to limit the position of the profile 3 to be processed. There are multiple positioning blocks, which are evenly distributed, and the size of each positioning block is but not limited to 30 mm (length) × 100 mm (width) × 6.5 mm (thickness).

[0046] In some optional embodiments, the stretch-bending die also includes a reinforcing rib 7, which is arranged on the outer arc surface of the arc-shaped steel plate 1 and is located above the flange baffle 6. The reinforcing rib 7 is designed to support the flange baffle 6 to prevent the flange baffle 6 from warping up during the stretch-bending process. In a specific embodiment, a 20 mm thick No. 45 steel plate is CNC-cut by a laser cutting machine to produce 28 right-angled trapezoidal reinforcing ribs 7. The dimensions of each reinforcing rib 7 are: 20 mm long on the upper side, 60 mm long on the lower side, and 80 mm in height. The reinforcing rib 7 is evenly fixed on the outer arc surface of the arc-shaped steel plate 1 by welding.

[0047] On the other hand, please see the attached Figure 6 As shown, an embodiment of the present invention provides a design method for a bending die, the bending die is the bending die of any one of the above embodiments, and the design method comprises the following steps: S1. Making curved steel plates: CNC cutting to obtain steel plates of preset sizes, and rolling the steel plates to bend them to a preset curvature radius; S2. Making an inner core: making a first arc-shaped support plate, an arc-shaped connecting plate and a second arc-shaped support plate, and welding them in sequence to form a C-shaped structure; S3. Welding: Weld the open end of the C-shaped structure to the outer arc surface of the arc-shaped steel plate.

[0048] In step S1, the steel plate can be No. 45 steel plate with a thickness of 20 mm. First, the steel plate is cut by CNC cutting using a laser cutting machine to cut a steel plate with a size of 8000 mm (length) × 330 mm (width) × 20 mm (thickness). Then, the steel plate is rolled using a three-axis arc plate rolling machine to bend its entire outer surface to a predetermined curvature, and finally the steel plate is formed into an arc structure with a curvature radius of R2134 mm.

[0049] In step S2, according to the shape of the profile to be processed, a No. 45 steel plate is selected to make the inner core of the contoured surface. The inner core is welded from three arc plates, namely the first arc support plate, the arc connecting plate and the second arc support plate. The arc connecting plate is used as the contoured surface, and its original size is 8000mm (length) × 91mm (width) × 10mm (thickness). Through the overall rolling treatment, an arc structure with a curvature radius of R2134mm is formed. The first arc support plate and the second arc support plate are respectively welded from multiple flat arc plates, usually 7 flat arc plates with a thickness of 10mm. The outer arc radius of each flat arc plate is R2225mm, the inner arc radius is R2134mm, and the width is 91mm.

[0050] In this embodiment, the stretch-bending die is the stretch-bending die of any one of the above embodiments, and therefore at least has the technical effects possessed by the stretch-bending die in the above embodiments, which will not be repeated here. In addition, the design method obtains a steel plate of a preset size by CNC blanking, and then rolls the steel plate after blanking to bend it to a preset radius of curvature, thereby obtaining an arc-shaped steel plate. Then, an inner core is formed by sequentially welding a first arc-shaped support plate, an arc-shaped connecting plate, and a second arc-shaped support plate. Finally, the inner core is fixed to the outer arc surface of the arc-shaped steel plate by welding, and the production of the stretch-bending die is finally completed. The method is simple to operate, easy to implement, and has a low manufacturing cost, which can effectively reduce production costs.

[0051] Please refer to the attached Figure 7 As shown, in some optional embodiments, welding the open end of the C-shaped structure to the outer curved surface of the curved steel plate specifically includes the following steps: S301, fixing the curved steel plate: placing the curved steel plate on the working platform, adjusting the curved steel plate by the pressing plate side pushing device to make it reach a preset curvature radius, and then fixing the curved steel plate on the working platform; S302, welding inner core: extend the arm of the profile bending machine to 180°, locate the center of the arm by using a laser level, mark the arc-shaped steel plate, locate the inner core according to the position of the laser level, and weld it to the arc-shaped steel plate.

[0052] In step S301, when the curved steel plate is fixed, it can be positioned with the aid of a test sample to ensure that the outer curved surface of the curved steel plate reaches a preset radius of curvature (e.g., R2134mm). The test sample is made of 2mm thick galvanized steel plate, and the arc curvature of the test sample is R2134mm. When there is a gap between the curved steel plate and the test sample, the curved steel plate can be adjusted by the pressure plate side push device to gradually reduce the gap and ensure that the outer curved surface of the curved steel plate reaches the preset radius of curvature requirement.

[0053] In step S302, the profile bending machine uses a 50T profile bending machine (maximum bending capacity is 50 tons), but is not limited to this model. In the actual stretching process, the load is set to 11T to pre-stretch the profile to be processed. Before pre-stretching, lubricating oil needs to be evenly applied to the profile to be processed and the surface where the inner core contacts the profile.

[0054] Please refer to the attached Figure 8 As shown, in some optional embodiments, the steps of manufacturing a first arc-shaped support plate, an arc-shaped connecting plate, and a second arc-shaped support plate, and welding them in sequence to form a C-shaped structure specifically include the following steps: S201, manufacturing a first arc support plate and a second arc support plate: each of the first arc support plate and the second arc support plate is composed of a plurality of planar arc plates, wherein the inner arc radius of the planar arc plate is the same as the preset curvature radius of the outer arc surface of the arc steel plate; S202, grinding welding grooves: grinding welding grooves on the outer sides of the first arc-shaped support plate and the second arc-shaped support plate respectively; S203, making an arc-shaped connecting plate: CNC cutting to obtain a steel plate of a preset size, and rolling the steel plate to bend it to a preset curvature radius, wherein the preset curvature radius of the inner arc surface of the arc-shaped connecting plate is the same as the outer arc radius of the plane arc plate; S204, argon arc welding: placing the first arc support plate on the platform, welding the first arc support plate to one side of the arc connecting plate using the outer side of the first arc support plate as a reference plane, and after welding, welding the outer side of the second arc support plate to the other side of the arc connecting plate.

[0055] In step S202, the size of the welding groove is but not limited to 4 mm×4 mm, forming a pyramid-shaped groove, which helps the welding material to fully penetrate and fuse, thereby improving the tightness and strength of the welded joint.

[0056] In some optional embodiments, the step of making the inner core further comprises the following steps: S205, placing a support block: placing the support block in the C-shaped structure; S206, Grinding fillet: Grinding fillet at the contact part between the inner core and the profile to be processed.

[0057] In step S205, the support block is an arc-shaped support block, whose outer arc radius is the same as the preset curvature radius of the inner arc surface of the arc-shaped connecting plate, and the inner arc radius is the same as the preset curvature radius of the outer arc surface of the arc-shaped steel plate. For example, the outer arc radius of the arc-shaped support block is R2225mm, the inner arc radius is R2134mm, and the height is 91mm.

[0058] In step S206, after the inner core is integrally welded, the contact area between the arc-shaped connecting plate and the processed profile is rounded, and the rounded corner size is but not limited to R3mm. Further, the contact surface between the first arc-shaped support plate and the processed profile is polished to make its surface smooth and flat.

[0059] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A stretch bending die, characterized in that: include: A curved steel plate having an outer curved surface with a preset radius of curvature; The inner core has an inner arc side with the same preset curvature radius as the outer arc surface and an outer arc side arranged opposite to the inner arc side, the inner arc side is fixedly arranged on the outer arc surface, and the outer arc side is used to bend the profile to be processed.

2. The stretch bending die according to claim 1, characterized in that: The inner core comprises: A first arc-shaped support plate, the inner side of which is fixedly arranged on the outer arc surface; A second arc-shaped support plate, the inner side of which is fixedly disposed on the outer arc surface and is disposed parallel to the first arc-shaped support plate; An arc-shaped connecting plate, one side of which is connected to the outer side of the first arc-shaped supporting plate, and the other side of which is connected to the outer side of the second arc-shaped supporting plate; The inner sides of the first arc-shaped support plate and the second support plate are the inner arc sides of the inner core, and the outer shape surface of the arc-shaped connecting plate is the outer arc side of the inner core.

3. The stretch bending die according to claim 2, characterized in that: The outer arc surface, the first arc-shaped support plate, the arc-shaped connecting plate and the second arc-shaped support plate are jointly arranged to form an accommodating cavity, and a supporting block is arranged in the accommodating cavity.

4. The stretch bending die according to claim 1, characterized in that: It also includes a pressure plate side push device, which is used to fix the arc-shaped steel plate on the working platform. The pressure plate side push device includes: A pressing plate abutting against the top of the arc-shaped steel plate; The side push piece is used to adjust the arc-shaped steel plate so that its outer arc surface reaches a preset curvature radius.

5. The stretch bending die according to claim 4, characterized in that: It also includes a flange baffle plate, which is used for being movably arranged on the top of the profile to be processed.

6. The stretch bending die according to claim 5, characterized in that: It also includes reinforcing ribs, which are arranged on the outer arc surface of the arc-shaped steel plate and are located above the flange baffle.

7. A method for designing a stretch bending die, characterized in that: The stretch bending die is the stretch bending die according to any one of claims 1 to 6, and the design method comprises the following steps: Making curved steel plates: CNC cutting is used to obtain steel plates of preset sizes, and the steel plates are rolled and bent to a preset curvature radius; Making the inner core: making a first arc-shaped support plate, an arc-shaped connecting plate and a second arc-shaped support plate, and welding them in sequence to form a C-shaped structure; Welding: Weld the open end of the C-shaped structure onto the outer arc surface of the arc-shaped steel plate.

8. The method for designing a stretch bending die according to claim 7, characterized in that: Welding the open end of the C-shaped structure onto the outer curved surface of the curved steel plate specifically comprises the following steps: Fixing the curved steel plate: placing the curved steel plate on a working platform, adjusting the curved steel plate by a pressing plate side-pushing device to make it reach a preset curvature radius, and then fixing the curved steel plate on the working platform; Welding the inner core: Extend the arm of the profile bending machine to 180°, locate the center of the arm using a laser level, mark the curved steel plate, locate the inner core according to the position of the laser level, and weld it to the curved steel plate.

9. The method for designing a stretch bending die according to claim 7, characterized in that: The steps of manufacturing a first arc-shaped support plate, an arc-shaped connecting plate, and a second arc-shaped support plate, and welding them in sequence to form a C-shaped structure, specifically include the following steps: The first arc support plate and the second arc support plate are made of a plurality of planar arc plates respectively, wherein the inner arc radius of the planar arc plate is the same as the preset curvature radius of the outer arc surface of the arc steel plate; Grinding welding grooves: Grinding welding grooves on the outer sides of the first arc-shaped support plate and the second arc-shaped support plate respectively; Making the arc-shaped connecting plate: CNC cutting to obtain a steel plate of a preset size, rolling the steel plate after cutting to bend it to a preset curvature radius, the preset curvature radius of the inner arc surface of the arc-shaped connecting plate is the same as the outer arc radius of the plane arc plate; Argon arc welding: Place the first arc-shaped support plate on the platform, and weld its outer side to one side of the arc-shaped connecting plate using the outer side as the reference plane. After welding, weld the outer side of the second arc-shaped support plate to the other side of the arc-shaped connecting plate.

10. The method for designing a stretch bending die according to claim 7, characterized in that: The steps of making the inner core also include the following steps: Placing a support block: placing the support block in the C-shaped structure; Grinding fillet: Grinding fillet at the contact position between the inner core and the profile to be processed.

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