A forming die and process for a center sill

Abstract

The application provides a middle transverse reinforcing beam forming die and process, which mainly comprises a drawing die, a trimming and punching die, a flanging and shaping die and a multi-surface punching die. The W-shaped groove-shaped workpiece is obtained by drawing the steel plate through the drawing die, the trimming and punching die is used for trimming and punching the groove-shaped workpiece, the flanging and shaping die is used for folding back the groove-shaped workpiece after trimming and punching, and the multi-surface punching die is used for punching the middle part and both sides of the Chinese character-shaped workpiece. The beneficial effects of the application are as follows: the W-shaped groove-shaped workpiece is first drawn, then the middle part of the groove-shaped workpiece is flattened and the both ends are folded back, compared with directly drawing the Chinese character-shaped workpiece with the vertical sides of both ends, the drawing height of the part is reduced, the drawing forming feasibility of the part is greatly improved, the forming defect problem which is prone to occur is solved, and the forming quality of the middle transverse reinforcing beam is improved; the number of die development is effectively reduced, the operation labor is reduced, the production machine is saved, and the energy consumption is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of stamping forming process and its die, in particular to a middle cross reinforcement beam forming die and process. BACKGROUND

[0002] The middle cross reinforcement beam is one of the most common parts in the truck cab, as shown in the drawings. Figure 1 The shape of the middle cross reinforcement beam is extremely complex and difficult to form. The current forming process mainly has the following problems:

[0003] The longitudinal section of the part is a "J" shape. This type of part has a large fluctuation, and is the most difficult shape to form in thin sheet parts. When forming, the material is pulled by bidirectional tensile force, and the edge of the part is easily pulled apart. Wrinkles in the middle part cannot be avoided, and serious ones may have a stacking phenomenon.

[0004] The upper arc of the part is 1321.5mm long, and the lower arc is 1415.3mm long, with a difference of 93.8mm. The straight line distance between the two intersection points of the upper and lower arcs is 672.4mm. If the drawing forming method is used, the material around the draw bead is pressed, the upper arc extends 649.1mm, which is 49%, and the lower arc extends 742.9mm, which is 52%. The material has a large difference in feeding speed, and there is a large shear stress on the sheet. It is very difficult to form a sheet with a thickness of 1.5mm. According to the shape of the part, it cannot be formed without modification. The two upward arms will seriously affect the forming.

[0005] In addition, multiple processes are required. There are two small flanges on both ends of the part, two round holes, two large diameter round holes on the front of the part, and one small diameter round hole. In addition to the overall shape forming, the hole processing process needs to be considered, and a large number of molds are required.

[0006] Therefore, how to reduce the production cost on the basis of ensuring the quality and precision of the middle cross reinforcement beam has become a problem in the processing and manufacturing of the middle cross reinforcement beam. SUMMARY

[0007] Therefore, in order to solve the problems of wrinkling, cracking, and stacking in the processing and forming of the complex J-shaped middle cross reinforcement beam, the embodiments of the present application provide a middle cross reinforcement beam forming die and process.

[0008] The embodiments of the present application provide a middle cross reinforcement beam forming die, which comprises:

[0009] A drawing die includes a first upper die and a first lower die. The first upper die includes a first upper die base and a first upper die cavity disposed at the bottom of the first upper die base. The first lower die includes a first lower die base and a first lower punch disposed at the top of the first lower die base. Both the first upper die cavity and the first lower punch are W-shaped, and the first upper die and the first lower die cooperate to draw a steel plate into a W-shaped groove part along the length direction.

[0010] A trimming and punching die is used to trim the sides of the grooved part and to punch the middle inflection point of the grooved part to form a first punch.

[0011] The flange forming mold includes a third upper mold and a third lower mold. The third upper mold includes a third upper mold base, two upper flange cutting blocks, a nitrogen spring, and an upper pressure core. The two upper flange cutting blocks are arranged parallel to each other at the bottom of the third upper mold base. The upper pressure core is arranged between the two upper flange cutting blocks and connected to the third upper mold base by the nitrogen spring. The third lower mold includes a third lower mold base, a third lower punch, and a lower movable block. The third lower punch is arranged at the top of the third lower mold base. The third lower punch includes a main boss and two side bosses arranged on both sides of the main boss. The main boss protrudes relative to the side bosses. The upper surface of the main boss is recessed downward to form a main support surface and two side support surfaces. The two side support surfaces are respectively located on both sides of the main support surface. The main support surface protrudes relative to the side support surface, and both ends of the main support surface and the side support surface are arc-shaped transitions. The lower movable block vertically penetrates the middle of the main support surface and is slidably connected to the third lower mold base.

[0012] The lower movable block can be raised to cooperate with the first punch to fix the grooved part after trimming and punching, and the nitrogen spring can make the upper pressure core pop out. When the third upper mold and the third lower mold are closed, the upper pressure core first presses down the middle inflection point of the grooved part and then presses down the part between the two side inflection points of the grooved part, so that the part between the two side inflection points of the grooved part is flattened. At the same time, the part of the grooved part located outside the two side inflection points is bent along the two ends of the main support surface and the side support surface.

[0013] Furthermore, it also includes a multi-faceted punching die, which includes a fourth upper die and a fourth lower die. The fourth upper die includes a fourth upper die base and a fourth upper punch disposed at the bottom of the fourth upper die base. The fourth upper punch is U-shaped and has at least one downward-protruding lower punch in the middle. The fourth lower die includes a fourth lower die base and a fourth lower die disposed at the top of the fourth lower die base. The fourth lower die is U-shaped.

[0014] Further, the fourth upper punch is provided with a side punch penetrating through both sides, the fourth upper die seat is provided with a wedge mounting seat and a sliding block slidingly connected with the wedge mounting seat on the outer side of both ends of the fourth upper punch, the bottom of the sliding block is provided with a wedge-shaped driving surface, the sliding block is connected with the side punch, the fourth lower die seat is provided with a wedge driver on the outer side of both ends of the fourth lower punch, and when the fourth upper die and the fourth lower die are closed, each wedge driver can drive the driving surface to slide the sliding block, so that the side punch moves towards the middle part of the fourth upper die.

[0015] Further, the fourth upper punch is provided with a side punch penetrating through both sides, the fourth upper die seat is provided with a wedge mounting seat and a sliding block slidingly connected with the wedge mounting seat on the outer side of both ends of the fourth upper punch, the bottom of the sliding block is provided with a wedge-shaped driving surface, the sliding block is connected with the side punch, the fourth lower die seat is provided with a wedge driver on the outer side of both ends of the fourth lower punch, and when the fourth upper die and the fourth lower die are closed, each wedge driver can drive the driving surface to slide the sliding block, so that the side punch moves towards the middle part of the fourth upper die.

[0016] Further, the width of the lower movable block is smaller than the internal width of the groove-shaped part, and the upper end of the lower movable block is locked by the positioning pin shaft.

[0017] Further, the two ends of the side support surface are outwardly expanded relative to the two ends of the main support surface.

[0018] Further, the third lower die seat is provided with a guide groove below the third lower punch, the upper end of the lower movable block penetrates through the middle part of the main boss and is connected with a sliding pressing plate at the lower end, and the sliding pressing plate is slidingly arranged in the guide groove.

[0019] Further, the trimming and punching die comprises a second upper die and a second lower die, the second upper die comprises a second upper die seat and a second upper punch arranged at the bottom of the second upper die seat, the second upper punch is provided with a first punch in the middle part and upper trimming cutter blocks on the opposite sides, the second lower die comprises a second lower die seat and a second lower punch arranged at the top of the second lower die seat, and the second lower punch is provided with a first punch sleeve corresponding to the first punch in the middle part.

[0020] In addition, the embodiment of the present application also provides a middle transverse reinforcing beam forming process using the above-mentioned middle transverse reinforcing beam forming die, and comprising the following steps:

[0021] S1, the steel plate is placed on the first lower punch, the first upper die and the first lower die are closed to draw the steel plate into a groove-shaped part, the groove-shaped part is W-shaped along the length direction and has a Chinese character shape in the longitudinal cross section, and the edges of the two side surfaces of the groove-shaped part have flanges;

[0022] S2, deburring and punching the groove-shaped workpiece by the deburring and punching die, forming a first punched hole at the middle inflection point of the groove-shaped workpiece;

[0023] S3, first place the deburred and punched groove-shaped workpiece on the third lower punch, make the lower movable block eject the first punched hole which is just supported at the middle inflection point of the groove-shaped workpiece and is locked with the first punched hole, the two edge inflection points of the groove-shaped workpiece are supported on the support surface and the two ends of the side support, then the upper pressing core is ejected by the nitrogen spring, then the third upper die and the third lower die are closed, the upper pressing core first presses the middle inflection point of the groove-shaped workpiece and then presses the part between the two edge inflection points of the groove-shaped workpiece, so that the part between the two edge inflection points of the groove-shaped workpiece is flattened, and the part outside the two edge inflection points of the groove-shaped workpiece is bent along the part of the main support surface and the side support surface, to obtain a U-shaped workpiece.

[0024] Further, S4 is further included, punching the middle and both sides of the U-shaped workpiece by a multi-surface punching die.

[0025] The technical scheme provided by the embodiment of the present application has the beneficial effects that:

[0026] 1. The middle transverse reinforcing beam forming die and process provided by the present application first draws a steel plate into a groove-shaped workpiece with a W shape by a drawing die, so that the middle web surface of the groove-shaped workpiece is bent downward by about 30° on both sides along the symmetry axis, to realize approximate equal-height drawing, then the groove-shaped workpiece is deburred and punched by a deburring and punching die, and the web surface of the W-shaped groove-shaped workpiece is turned back to form a U-shaped workpiece by a flanging and shaping die, which reduces the part drawing height and greatly improves the part drawing forming feasibility, solves the problem of easy forming defects, and improves the forming quality of the middle transverse reinforcing beam.

[0027] 2. The middle transverse reinforcing beam forming die and process provided by the present application can effectively reduce the number of die development, reduce the operation labor, save production machines and reduce energy consumption. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a schematic view of the middle transverse reinforcing beam in the background art;

[0029] Figure 2 is a schematic view of the drawing die;

[0030] Figure 3 is a schematic view of the deburring and punching die;

[0031] Figure 4 is a sectional view of the flanging and shaping die;

[0032] Figure 5 is a schematic view of the third upper die;

[0033] Figure 6 is a schematic view of the third lower die;

[0034] Figure 7 is a schematic view of the trimmed and punched channel-shaped part mounted on the third lower die;

[0035] Figure 8 is a schematic view of the multi-sided punching die.

[0036] In the drawings: 100, middle cross reinforcement beam; 101, trimmed and punched channel-shaped part; 1, drawing die; 11, first upper die; 111, first upper die holder; 112, first upper die cavity; 12, first lower die; 121, first lower die holder; 122, first lower die punch; 2, trimming and punching die; 21, second upper die; 211, second upper die holder; 212, second upper die cavity; 213, upper trimming cutter block; 214, first punch; 22, second lower die; 221, second lower die holder; 222, second lower die punch; 223, first punch sleeve; 224, scrap cutter; 3, flanging and shaping die; 31, third upper die; 311, third upper die holder; 312, upper flanging cutter block; 313, upper pressure core; 314, nitrogen gas spring; 32, third lower die; 321, third lower die holder; 322, third lower die punch; 323, lower movable block; 324, sliding pressure plate; 325, main boss; 325a, main support surface; 325b, side support surface; 326, side boss; 327, positioning pin; 4, multi-sided punching die; 41, fourth upper die; 411, fourth upper die holder; 412, fourth upper die punch; 413, lower punch; 414, side punch; 415, sliding block; 416, inclined wedge mounting seat; 417, movable plate; 418, fixed plate; 419, elastic member; 42, fourth lower die; 421, fourth lower die holder; 422, fourth lower die cavity; 423, second punch sleeve; 424, third punch sleeve; 425, inclined wedge driver. DETAILED DESCRIPTION

[0037] In order to make the objects, technical solutions and advantages of the present application clearer, the following will further describe the embodiments of the present application with reference to the drawings. The following introduces a relatively preferred one of the multiple possible embodiments of the present application, which is intended to provide a basic understanding of the present application, but is not intended to identify key or decisive elements or limit the scope of protection.

[0038] In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary, and not as a limitation. Thus, other examples of the example embodiments can have different values.

[0039] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0040] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures. Also, it should be understood that, for ease of description, the dimensions of the various parts shown in the figures are not drawn to actual scale.

[0041] It should be further noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0042] Please refer to Figures 2-8 An embodiment of the present invention provides a forming mold for a transverse reinforcing beam, used to manufacture such a beam. Figure 1 The central transverse reinforcing beam 100 shown in the figure mainly includes a drawing die 1, a trimming and punching die 2, a flanging and shaping die 3, and a multi-faceted punching die 4.

[0043] like Figure 2 As shown, the drawing die 1 includes a first upper die 11 and a first lower die 12. The first upper die 11 includes a first upper die base 111 and a first upper die cavity 112 disposed at the bottom of the first upper die base 111. The first lower die 12 includes a first lower die base 121 and a first lower punch 122 disposed at the top of the first lower die base 121. Both the first upper die cavity 112 and the first lower punch 122 are W-shaped.

[0044] The first lower mold 12 is fixed, and the steel plate is placed inside the first lower mold 12. The first upper mold 11 moves downward and closes with the first lower mold 12 to stretch the steel plate into a W-shaped groove part along the length direction. At the same time, the longitudinal cross-sectional shape of the groove part is Z-shaped, so that the two side edges of the groove part form flanges.

[0045] like Figure 3 As shown, the trimming and punching die 2 is mainly used for trimming the sides of the grooved part and punching the middle inflection point of the grooved part to form a first punch. The trimming and punching die includes a second upper die 21 and a second lower die 22.

[0046] Specifically, the second upper die 21 comprises a second upper die seat 211 and a second upper cavity die 212 arranged at the bottom of the second upper die seat 211, the second upper cavity die 212 is approximately W-shaped, a first punch 214 is arranged in the middle of the second upper cavity die 212, and upper trimming cutter blocks 213 are arranged at the opposite sides of the second upper cavity die 212.

[0047] The second lower die 22 comprises a second lower die seat 221 and a second upper cavity die 212 arranged at the top of the second lower die seat 221, the second upper cavity die 212 is approximately W-shaped, a first punch 214 is arranged in the middle of the second upper cavity die 212, and upper trimming cutter blocks 213 are arranged at the opposite sides of the second upper cavity die 212.

[0048] The second lower die 22 is fixedly arranged, the groove-shaped part is arranged on the second upper cavity die 222, the second upper die 21 moves downward to combine with the second lower die 22, the upper trimming cutter blocks 213 cut off the excess part of the edge of the groove-shaped part, and the first punch 214 cooperates with the first punch sleeve 223 to punch a hole in the middle of the groove-shaped part to form a first punched hole.

[0049] As shown in the drawings, the flanging and shaping die 3 mainly comprises a third upper die 31 and a third lower die 32. Figures 4-7

[0050] Specifically, the third upper die 31 comprises a third upper die seat 311, two upper flanging cutter blocks 312, a nitrogen gas spring 314 and an upper pressing core 313, the two upper flanging cutter blocks 312 are arranged in parallel at the bottom of the third upper die seat 311, the upper pressing core 313 is arranged between the two upper flanging cutter blocks 312, the nitrogen gas spring 314 is arranged between the two upper flanging cutter blocks 312 and connected to the third upper die seat 311, the nitrogen gas spring 314 is located above the upper pressing core 313, and the nitrogen gas spring 314 is connected to the upper pressing core 313.

[0051]

[0052] The third lower die 32 comprises a third lower die seat 321, a third upper cavity die 322 and a lower movable block 323, wherein the third upper cavity die 322 is arranged at the top of the third lower die seat 321, the third upper cavity die 322 comprises a main boss 325 and two side bosses 326 arranged at the two sides of the main boss 325, and the main boss 325 is convex relative to the side bosses 326.

[0053] ​​And, the upper surface of the main boss 325 is concave downward to form a main supporting surface 325a and two side supporting surfaces 325b on both sides of the main supporting surface 325a, the main supporting surface 325a is convex upward relative to the side supporting surfaces 325b, and both ends of the main supporting surface 325a and the side supporting surfaces 325b are arc-shaped transitions, the slot-shaped workpiece 101 after trimming and punching can be seated on the main boss 325, the main supporting surface 325a supports the back of the middle plane of the slot-shaped workpiece, and the side supporting surfaces 325b are used to support the flanges of the slot-shaped workpiece 101 after trimming and punching.

[0054] The lower movable block 323 vertically penetrates the middle part of the main supporting surface 325a and is in sliding connection with the third lower die seat 321. Specifically, the third lower die seat 321 is provided with a guide groove below the third lower punch 322, the upper end of the lower movable block 323 penetrates the middle part of the main boss 325, and the lower end is connected with a sliding pressing plate 324, the sliding pressing plate 324 is slidably arranged in the guide groove, and by pushing the sliding pressing plate 324, the lower movable block can be pushed out upward from the main supporting surface 325a.

[0055] The third lower die 32 is fixedly arranged, the slot-shaped workpiece 101 after trimming and punching is placed on the main boss 325, and the lower movable block 323 can be raised to cooperate with the first punching to fix the slot-shaped workpiece 101 after trimming and punching. Here, the width of the lower movable block 323 is smaller than the internal width of the slot-shaped workpiece, and the upper end of the lower movable block 323 can be locked with the first punching through a positioning pin 327 shaft.

[0056] Then the nitrogen spring 314 can make the upper pressing core 313 pop out, the third upper die 31 moves downward to close with the third lower die 32, the upper pressing core 313 first presses downward the middle inflection point of the slot-shaped workpiece and then presses downward the part between the two edge inflection points of the slot-shaped workpiece, so that the part between the two edge inflection points of the slot-shaped workpiece is flattened, and the part of the slot-shaped workpiece outside the two edge inflection points is bent along the parts of the two ends of the main supporting surface 325a and the side supporting surfaces 325b.

[0057] Preferably, the two ends of the side supporting surfaces 325b are outwardly expanded relative to the two ends of the main supporting surface 325a. In this way, when the part of the slot-shaped workpiece between the two edge inflection points is pressed downward, the part of the slot-shaped workpiece outside the two edge inflection points can be well bent along the two ends of the side supporting surfaces 325b and the two ends of the main supporting surface 325a, so that the slot-shaped workpiece is bent back into a zigzag-shaped workpiece.

[0058] As Figure 8As shown, the multi-surface piercing die 4 is used for piercing the middle and both sides of the hairpin-shaped workpiece, and specifically comprises a fourth upper die 41 and a fourth lower die 42.

[0059] Specifically, the fourth upper die 41 comprises a fourth upper die seat 411 and a fourth upper punch 412 arranged at the bottom of the fourth upper die seat 411. The fourth upper punch 412 is hairpin-shaped and has at least one lower convex lower punch 413 arranged at the middle portion.

[0060] The fourth lower die 42 comprises a fourth lower die seat 421 and a fourth lower recess 422 arranged at the top of the fourth lower die seat 421. The fourth lower recess 422 is hairpin-shaped. The fourth lower recess 422 is further provided with at least one second punch sleeve 423. Each second punch sleeve 423 cooperates with a lower punch 413, so that each lower punch 413 can pierce the middle plane of the hairpin-shaped workpiece.

[0061] The fourth upper punch 412 is further provided with a side punch 414 arranged through both sides. The fourth upper die seat 411 is further provided with a wedge mounting seat 416 and a slider 415 connected to the wedge mounting seat 416 at the outer side of both ends of the fourth upper punch 412. The slider 415 can slide obliquely along the wedge mounting seat 416. The bottom of the slider 415 is provided with a wedge-shaped driving surface. The slider 415 is connected to the side punch 414. The fourth lower die seat 421 is further provided with a wedge driver 425 at the outer side of both ends of the fourth lower recess 422. The fourth upper die 41 is further provided with a third punch sleeve 424 corresponding to the side punch 414. When the fourth upper die 41 and the fourth lower die 42 are closed, each wedge driver 425 can drive the driving surface to slide the slider 415, so that the side punch 414 moves towards the middle portion of the fourth upper die 41, cooperates with the third punch sleeve 424, and then can pierce the side surface of the end portion of the hairpin-shaped workpiece.

[0062] More specifically, the fourth upper punch 412 is further provided with a movable plate 417 and a fixed plate 418 between the end portion and the slider 415. The movable plate 417 is connected to the slider 415. The movable plate 417 and the fixed plate 418 are provided with an elastic member 419 therebetween. The elastic member 419 can be a spring. The fixed plate 418 is fixedly arranged on the fourth upper die seat 411 and abuts against the end portion of the fourth upper punch 412. The rear end of the side punch 414 penetrates through the fixed plate 418 and is connected to the movable plate 417.

[0063] Furthermore, the embodiment of the present application also provides a middle transverse reinforcing beam forming process using the middle transverse reinforcing beam forming die and comprising the following steps:

[0064] S1, drawing a W-shaped groove-shaped workpiece by a drawing die 1: placing a steel plate on the first lower convex die 122, clamping the first upper die 11 and the first lower die 12 to draw the steel plate into a groove-shaped workpiece, the groove-shaped workpiece having flanges on both side edges, and the groove-shaped workpiece being W-shaped along the length direction. Here, the middle web surface of the W-shaped groove-shaped workpiece is bent downward by about 30° on both sides along the symmetry axis, realizing approximate isometric drawing, reducing the drawing height, and improving the drawing feasibility compared with directly drawing a few-shaped workpiece with vertical side edges at both ends. Meanwhile, the inner surfaces of the first lower convex die 122 and the first upper concave die 112 are changed from planes to conical surfaces, which can reduce wrinkles and cracks caused by uneven material flow during the drawing of the plate.

[0065] S2, trimming and punching the groove-shaped workpiece by the trimming and punching die 2: trimming the excess part of the edge of the groove-shaped workpiece by the upper trimming cutter block 213, and punching the first punch hole at the middle corner of the groove-shaped workpiece by the first punch 214 cooperating with the first punch sleeve 223.

[0066] S3, folding back the groove-shaped workpiece 101 after trimming and punching by the flanging and shaping die 3:

[0067] First, place the groove-shaped workpiece after trimming and punching on the third lower convex die 322, so that the lower movable block 323 ejects and locks the first punch hole just supported at the middle corner of the groove-shaped workpiece, and the two edge corner parts of the groove-shaped workpiece located at both sides are supported on the support surface and the two ends of the side support, then the upper pressing core 313 is ejected by the nitrogen gas spring 314, then the third upper die 31 and the third lower die 32 are clamped, the upper pressing core 313 first presses down the middle corner of the groove-shaped workpiece and then presses down the part between the two edge corners of the groove-shaped workpiece, so that the part between the two edge corners of the groove-shaped workpiece is flattened, and the part of the groove-shaped workpiece located outside the two edge corners is bent along the part at both ends of the main support surface 325a and the side support surface 325b, to obtain a few-shaped workpiece.

[0068] S4, punching the middle part and both sides of the few-shaped workpiece by the multi-surface punching die 4: punching the middle part of the few-shaped workpiece by the lower punch 413, and punching the side surface of the end part of the few-shaped workpiece by the side punch 414.

[0069] In this article, the front, back, up, down and other orientation words are defined with the position of the parts in the drawing and the position of the parts relative to each other, just to express the technical scheme clearly and conveniently. It should be understood that they are relative concepts, which can be changed accordingly according to different ways of use and placement, and the use of the orientation words should not limit the scope of the application.

[0070] In the case of no conflict, the above-mentioned embodiments and features in the embodiments can be combined with each other. The above-mentioned only is the preferred embodiment of the application, and does not limit the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application should be included in the protection scope of the application.

Claims

1. A forming die for a center sill, characterized by, The application relates to a die set for manufacturing a W-shaped groove-shaped workpiece, which comprises a first upper die and a first lower die, the first upper die comprises a first upper die seat and a first upper concave die arranged at the bottom of the first upper die seat, the first lower die comprises a first lower die seat and a first lower convex die arranged at the top of the first lower die seat, the first upper concave die and the first lower convex die are both W-shaped, and the first upper die and the first lower die can cooperate to draw a steel plate into a W-shaped groove-shaped workpiece. The application also relates to a trimming and punching die set for trimming the two sides of the W-shaped groove-shaped workpiece and punching a first punching hole at the middle corner of the W-shaped groove-shaped workpiece. The application further relates to a flanging and shaping die set, which comprises a third upper die and a third lower die, the third upper die comprises a third upper die seat, two upper flanging blocks, a nitrogen spring and an upper pressing core, the two upper flanging blocks are arranged in parallel at the bottom of the third upper die seat, the upper pressing core is arranged between the two upper flanging blocks and connected to the third upper die seat through the nitrogen spring, the third lower die comprises a third lower die seat, a third lower convex die and a lower movable block, the third lower convex die is arranged at the top of the third lower die seat, the third lower convex die comprises a main convex platform and two side convex platforms arranged at the two sides of the main convex platform, the main convex platform is convex upward relative to the side convex platforms, the upper surface of the main convex platform is concave downward to form a main supporting surface and two side supporting surfaces, the two side supporting surfaces are respectively arranged at the two sides of the main supporting surface, the main supporting surface is convex upward relative to the side supporting surfaces, and the two ends of the main supporting surface and the side supporting surfaces are both arc-shaped transitions, and the lower movable block vertically penetrates the middle part of the main supporting surface and is slidably connected to the third lower die seat. The lower movable block can be raised to fix the W-shaped groove-shaped workpiece after trimming and punching, and the nitrogen spring can make the upper pressing core pop out, so that, when the third upper die and the third lower die are closed, the upper pressing core first presses down the middle corner of the W-shaped groove-shaped workpiece and then presses down the part between the two side corners of the W-shaped groove-shaped workpiece, so that the part between the two side corners of the W-shaped groove-shaped workpiece is flattened, and the part of the W-shaped groove-shaped workpiece outside the two side corners is bent along the two ends of the main supporting surface and the side supporting surfaces. The application further relates to a multi-surface punching die set, which comprises a fourth upper die and a fourth lower die, the fourth upper die comprises a fourth upper die seat and a fourth upper convex die arranged at the bottom of the fourth upper die seat, the fourth upper convex die is in the shape of a Chinese character 'er', and at least one lower convex lower punching head is arranged at the middle part of the fourth upper convex die, the fourth lower die comprises a fourth lower die seat and a fourth lower concave die arranged at the top of the fourth lower die seat, and the fourth lower concave die is in the shape of a Chinese character 'er'.

2. A cross member forming die as claimed in claim 1 wherein: ​ 3. A cross member forming die as claimed in claim 2 wherein: The fourth upper punch is provided with a side punching punch penetrating through both sides, the fourth upper die seat is provided with a wedge mounting seat and a sliding block slidingly connected with the wedge mounting seat on the outer side of both ends of the fourth upper punch, the sliding block is provided with a wedge-shaped driving surface at the bottom, the sliding block is connected with the side punching punch, the fourth lower die seat is provided with a wedge driver on the outer side of both ends of the fourth lower punch, and when the fourth upper die and the fourth lower die are closed, each wedge driver can drive the driving surface to slide the sliding block, so that the side punching punch moves towards the middle part of the fourth upper die.

4. A cross member forming die as claimed in claim 3 wherein: The fourth upper punch is provided with a side punching punch penetrating through both sides, the fourth upper die seat is provided with a wedge mounting seat and a sliding block slidingly connected with the wedge mounting seat on the outer side of both ends of the fourth upper punch, the sliding block is provided with a wedge-shaped driving surface at the bottom, the sliding block is connected with the side punching punch, the fourth lower die seat is provided with a wedge driver on the outer side of both ends of the fourth lower punch, and when the fourth upper die and the fourth lower die are closed, each wedge driver can drive the driving surface to slide the sliding block, so that the side punching punch moves towards the middle part of the fourth upper die.

5. A cross member forming die as claimed in claim 1 wherein: The width of the lower movable block is smaller than the internal width of the groove-shaped part, and the upper end of the lower movable block can be locked by a positioning pin shaft.

6. A cross member forming die as claimed in claim 1 wherein: The two ends of the side support surface are outwardly expanded relative to the two ends of the main support surface.

7. A cross member forming die as claimed in claim 1 wherein: The third lower die seat is provided with a guide groove below the third lower punch, the upper end of the lower movable block penetrates through the middle part of the main boss, and the lower end is connected with a sliding pressing plate, which is slidingly arranged in the guide groove.

8. A cross member forming die as claimed in claim 1 wherein: The trimming and punching die comprises a second upper die and a second lower die, the second upper die comprises a second upper die seat and a second upper punch arranged at the bottom of the second upper die seat, the second upper punch is provided with a first punch in the middle part, and the opposite two sides of the second upper punch are provided with upper trimming cutter blocks, the second lower die comprises a second lower die seat and a second lower punch arranged at the top of the second lower die seat, and the middle part of the second lower punch is provided with a first punch sleeve corresponding to the first punch.

9. A process for forming a center sill, characterized by: The method comprises the following steps: S1, placing a steel plate on the first lower punch, closing the first upper die and the first lower die to draw the steel plate into a groove-shaped part, the groove-shaped part is W-shaped along the length direction and has a Chinese character-shaped longitudinal section shape, and the edges of the two side surfaces of the groove-shaped part have flanges; S2, trimming and punching the groove-shaped part by the trimming and punching die to form a first punch hole at the middle corner of the groove-shaped part. S3, first put the slot-shaped workpiece after trimming and punching on the third lower punch, make the lower movable block eject the first punching hole just supported at the middle inflection point of the slot-shaped workpiece and lock with the first punching hole, the two edge inflection point parts of the slot-shaped workpiece located on both sides are supported on the support surface and the two ends of the side support, then the upper pressing core is ejected by the nitrogen spring, then the third upper die and the third lower die are closed, the upper pressing core first presses the middle inflection point of the slot-shaped workpiece, then presses the part between the two edge inflection points of the slot-shaped workpiece, so that the part between the two edge inflection points of the slot-shaped workpiece is flattened, and the part of the slot-shaped workpiece outside the two edge inflection points is bent along the part of the main support surface and the side support surface, to obtain a few-shaped workpiece.

10. A process for forming a cross-car beam according to claim 9, wherein, Further comprising S4, punching the middle and both sides of the few-shaped workpiece by a multi-surface punching die.

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