A stamping die and a forming method for a U-shaped beam

Abstract

The present application discloses a stamping die and a method for forming a U-shaped beam. The stamping die comprises an upper die assembly and a lower die assembly. The upper die assembly comprises a die insert arranged longitudinally, the cross section of the die insert being concave-shaped. The lower die assembly comprises a punch insert, the projection of the punch insert on a horizontal plane and the projection of the die insert on a horizontal plane being staggered longitudinally. The punch insert is arranged near one end face of the die insert and is spaced apart from the end face by a distance T. The punch insert comprises a base portion and a forming portion connected to the base portion. The lateral distance between the two side edges of the cross section of the forming portion and the vertical center line of the forming portion gradually decreases from bottom to top, so that the cross section of the forming portion is in a shape with a larger bottom and a smaller top. The thinning rate of the stamping die and the U-shaped beam formed by the stamping die is reduced to about 10%, and the cracking rate is reduced to about 0.01%. The product qualification rate is significantly improved and the production cost is significantly reduced.

Description

Technical Field

[0001] The present application relates to the field of stamping technology, and in particular to a stamping die and a forming method of a U-shaped beam based on the stamping die. Background Art

[0002] Figure 6 The figure is a three-dimensional diagram of a typical U-shaped beam. The top edge, side edges, and corners between the top and side edges of the beam body 101 of the U-shaped beam are all provided with flanges. The top edge flange 102a, side edge flanges 102b, and corner flanges 1023 are connected to form an integrated circumferential flange 102.

[0003] At present, in the process of forming such a U-shaped beam, the beam body (such as Figure 7 Left), and then the end of the stamped beam body is flanged to form an integrated circumferential flange (such as Figure 7 During the flanging process, the flanging (especially at the corners) is prone to excessive thinning (usually requiring a thinning rate of less than 20% of the sheet thickness) and cracking, with the cracking rate as high as 30%, resulting in a low product qualification rate.

[0004] In view of this, how to alleviate the technical problems of excessive thinning rate and cracking at the flange is something that technical personnel in this field need to solve. Summary of the Invention

[0005] In order to solve the above technical problems, the present application provides a stamping die, which includes:

[0006] An upper die assembly, the upper die assembly comprising a die insert arranged in a longitudinal direction, the die insert having a concave cross-section;

[0007] The lower mold assembly includes a punch insert, the projection of the punch insert on the horizontal plane and the projection of the die insert on the horizontal plane are staggered in the longitudinal direction, and the punch insert is arranged close to one end face of the die insert and is spaced a distance T from the end face.

[0008] In one embodiment of the stamping die, the male mold insert includes a base portion and a forming portion connected to the base portion; the lateral distance between the two side edges of the cross section of the forming portion and the vertical center line of the forming portion gradually decreases from bottom to top, so that the cross section of the forming portion is large at the bottom and small at the top; the projections of the two corners of the die insert cavity on the transverse plane are correspondingly arranged above the projections of the two side edges of the cross section of the forming portion on the transverse plane.

[0009] In one embodiment of the stamping die, the cross section of the forming portion is an isosceles trapezoid.

[0010] In one embodiment of the stamping die, the angle α between the two sides of the isosceles trapezoid and the longitudinal center line of the forming portion is in the range of 20°≤α≤45°.

[0011] In one embodiment of the stamping die, the distance T is greater than the thickness of the sheet material currently used in production.

[0012] In one embodiment of the stamping die, the distance T is equal to twice the thickness of the sheet material currently used in production.

[0013] In one embodiment of the stamping die, the upper die assembly further includes an upper die movable core, the lower die assembly includes a lower die movable core, and the elasticity of the lower die movable core is greater than that of the upper die movable core.

[0014] The present application also provides a U-shaped beam forming method, which is implemented based on any of the above-mentioned stamping dies, and the forming method comprises the following steps:

[0015] S1. Drop the sheet material between the upper die assembly and the lower die assembly of the stamping die so that the end of the sheet material is located above the punch insert;

[0016] S2. Using a stamping die to stamp the sheet material, stamping out the beam body and the integral circumferential flanges at the ends of the beam body in one go;

[0017] S3. Reshape the side of the beam body;

[0018] S4. Punch and trim to shape the integrated circumferential flange.

[0019] The U-shaped beam formed using the above-mentioned stamping die and forming method has a thinning rate reduced to about 10%, which is far lower than the 20% thinning rate required by the product. The cracking rate is also reduced from 30% to about 0.01%. The product qualification rate is significantly improved and the production cost is significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the stamping die provided by the present invention;

[0021] Figure 2 for Figure 1 Side view of

[0022] Figure 3 for Figure 1 A top view of

[0023] Figure 4 Schematic diagram of the upper die assembly of the stamping die descending to different positions during the forming process;

[0024] Figure 5 For forming by the forming method provided by this application Figure 6 A schematic diagram of a U-shaped beam is shown;

[0025] Figure 6 A three-dimensional diagram of a typical U-shaped beam

[0026] Figure 7 The forming method is to use the method of stamping first and then flanging Figure 6 A schematic diagram of a U-shaped beam is shown;

[0027] The following are the descriptions of the reference numerals:

[0028] 100 U-shaped beam, 101 beam body, 101a side surface, 102 integrated circumferential flange, 102a top edge flange, 102b side edge flange, 102c corner flange.

[0029] 200 stamping die, 201 die insert, 202 punch insert, 202a base portion, 202b forming portion, 203 lower die movable core;

[0030] 300 sheets. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the technical solution of the present application, the technical solution of the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0032] The stamping die 200 provided in this application includes: an upper die assembly and a lower die assembly. Figure 1 、 Figure 2 or Figure 3 The upper die assembly includes a die insert 201 arranged in the longitudinal direction, and the cross section of the die insert 201 is concave. In addition, the upper die assembly also includes an upper die movable core (not shown in the figure). The upper die movable core is a common component in this field.

[0033] like Figure 3 The lower die assembly includes a punch insert 202. The projection of the punch insert 202 on a horizontal plane (i.e., a plane perpendicular to the vertical direction and parallel to the longitudinal direction) and the projection of the die insert 201 on the horizontal plane are staggered in the longitudinal direction. The punch insert 202 is arranged near one end face of the die insert 201 and is spaced a distance T from the end face.

[0034] In addition, if Figure 4 The lower mold assembly further comprises a lower mold movable core 203, which is a conventional component in the art. The elasticity of the lower mold movable core 203 is greater than that of the upper mold movable core, which is more conducive to the forming of the flanging.

[0035] The punching die 200 is used to form Figure 6In the U-shaped beam 100 shown, the upper die assembly and the die insert 201 are used to press-form an integral circumferential flange 102 at the end of the beam body 101. This eliminates the need for a separate flange forming process and significantly mitigates issues such as excessive thinning and cracking. The stamping process of the U-shaped beam 100 will be described in detail later.

[0036] Specifically, such as Figure 2 The male mold insert 202 includes a base portion 202a and a forming portion 202b connected to the base portion 202a. The lateral distance between the two sides of the cross section of the forming portion 202b and the vertical center line Z of the forming portion 202b gradually decreases from bottom to top, so that the cross section of the forming portion 202b has a larger bottom and smaller top shape.

[0037] Furthermore, the two corners of the cavity of the die insert 201 are in the transverse plane (i.e., a plane parallel to the transverse direction and perpendicular to the longitudinal direction, Figure 1 The projection on the horizontal plane (the dotted line is a horizontal plane) is correspondingly arranged above the projection of the two sides of the cross section of the forming part 202b on the horizontal plane. In other words, when viewed from the length direction of the part (i.e. the longitudinal direction in the figure), the projection of the two corners of the die cavity of the die insert 201 along the stamping direction falls on the two sides of the cross section of the forming part 202b. Figure 2 It is understood that the two cavity corners of the die insert 201 and the two sides of the cross section of the forming portion 202b are projected onto the same transverse plane, and the projection is Figure 2 In the state shown, four vertical leads are then made in the horizontal plane through the inflection points at both ends of the two corners of the cavity of the die insert 201, and the lower ends of the two vertical leads passing through the inflection points at both ends of one corner intersect with one side of the cross section of the forming portion 202b, and the lower ends of the two vertical leads passing through the inflection points at both ends of the other corner intersect with the other side of the cross section of the forming portion 202b.

[0038] By adopting the above-mentioned forming part 202b, the integrated circumferential flange 102 can be formed in steps, first forming the top edge flange 102a and the side edge flange 102b, and then forming the corner flange 102c, which can further alleviate the problem of excessive thinning rate and cracking of the product.

[0039] Specifically, the cross section of the forming portion 202b can be an isosceles trapezoid, hemispherical, semi-elliptical, etc. In the illustrated embodiment, the cross section of the forming portion 202b is an isosceles trapezoid, which has a more significant effect in alleviating excessive thinning rate and cracking of the product.

[0040] Specifically, the range of the angle α between the two sides of the isosceles trapezoid and the longitudinal center line Z of the forming portion 202b is: 20°≤α≤45°. More preferably, the range of α is: 30°≤α≤40°. Within this range, the effect of alleviating excessive thinning rate and cracking of the product is more significant.

[0041] Specifically, the distance T is greater than the thickness of the sheet material 300 currently in production. This reduces material resistance during the flanging step-by-step forming process, further helping to lower the thinning rate and cracking rate. More preferably, the distance T is equal to twice the thickness of the sheet material 300 currently in production. When the distance T is equal to twice the thickness of the sheet material 300 currently in production, it is sufficient to prevent the product from cracking during the stamping process and also prevents cracking and overlap during the subsequent shaping process.

[0042] The forming method of the U-shaped beam 100 provided in the present application is implemented based on the above-mentioned stamping die 200. Specifically, the forming method includes the following steps:

[0043] S1. Drop the sheet material 300 between the upper die assembly and the lower die assembly of the stamping die 200 , with the end of the sheet material 300 located above the punch insert 202 .

[0044] At this time, the upper mold assembly is in Figure 4 In the position shown in Figure A, the upper die assembly has not yet contacted the sheet material 300, and the sheet material 300 is in Figure 5 The initial state shown in FIG. A, the thickness of the sheet material 300 refers to the thickness of the sheet material in the initial state.

[0045] For the sheet material 300, the quality of the trimming should be strictly controlled to eliminate the cracks and prevent the sheet material 300 from being torn during forming.

[0046] S2. Punch the sheet material 300 using the punching die 200. Since the punching die 200 is provided with the punch insert 202, the beam body 101 and the integral circumferential flange 102 at the end of the beam body can be punched out at one time during the punching process.

[0047] That is to say, after the stamping is completed, not only the beam body 101 is formed, but also the integrated circumferential flange 102 is formed. The beam body 101 and the integrated circumferential flange 102 are stamped out at one time by the stamping die 200. After completing this step, the product is Figure 5 The shape shown in Figure B

[0048] In the past, during the forming process of the U-shaped beam 100, Figure 7First, the beam body 101 is stamped and formed, and then the flanging is performed. This forming method, on the one hand, causes the sheet material 300 to undergo multiple cold working processes, which hardens the sheet material 300 and makes it more susceptible to excessive thinning and cracking. On the other hand, the structural strength of the sheet material 300 is already very high after stamping, and material flow or material displacement replenishment from the sheet material 300 is no longer available during flanging, which also makes excessive thinning and cracking more likely. These two factors lead to a product thinning rate exceeding 20% ​​and a cracking rate as high as 30%.

[0049] In comparison, the forming method provided in the present application combines the stamping forming process and the flanging forming process into one. In the process of stamping the beam body 101, an integrated circumferential flange 102 is also stamped out. Therefore, the forming process is reduced, so that the hardness and structural strength of the sheet material 300 are not very large during the flanging forming process. Therefore, in the process of flanging forming, material flow supplement or material displacement supplement can be obtained from the sheet material 300, thereby reducing the thinning rate and cracking rate, and improving the product qualification rate.

[0050] Furthermore, when the lateral distance between the two sides of the cross section of the forming portion 202b of the male mold insert 202 and the vertical center line Z of the forming portion 202b gradually decreases from bottom to top, so that the cross section of the forming portion 202b is in a shape of a large bottom and a small top, and the projections of the two cavity corners of the female mold insert 201 on the transverse plane are correspondingly arranged above the projections of the two sides of the cross section of the forming portion 202b on the transverse plane, under the action of the inclination of the two sides of the cross section of the two forming portions 202b, the punching In the process of forming the integrated circumferential flange 102, the integrated circumferential flange 102 can be formed in steps. The top edge flange 102a and the side edge flange 102b will be formed first, and then the corner flange 102c will be formed. That is to say, the corner flange 102c is formed after the top edge flange 102a and the side edge flange 102b. In this way, a certain amount of material can be supplemented from the top edge flange 102a and the side edge flange 102b during the forming process of the corner flange 102c, thereby further reducing the thinning rate and cracking rate.

[0051] Specifically, the step-by-step forming process of the integrated circumferential flange 102 is as follows: when the upper mold assembly descends to Figure 4 At the position shown in FIG. B, the end of the sheet 300 begins to form a top flange 102a and a side flange 102b under the punching action of the upper die assembly and the punch insert 202; Figure 4 At the position shown in Figure C, the top edge flange 102a and the side edge flange 102b are completed, and the corner flange 102c begins to form; when the upper mold assembly moves down to Figure 4 At the position shown in FIG. D , the corner flange 102 c is completed, and thus, the integral circumferential flange 102 is formed by stamping.

[0052] Furthermore, the material flow resistance is relatively large during the process of forming the top edge flange 102a and the side edge flange 102b before the corner flange 102c (i.e., step-by-step forming of the flange). When the distance T is greater than the thickness of the sheet 300, the material resistance of the step-by-step flanging can be reduced to a certain extent, thereby further reducing the thinning rate and cracking rate.

[0053] S3. Reshape the side surface 101a of the beam body.

[0054] By shaping the side surface 101a of the beam body, springback can be eliminated and the size of the longitudinal side surface 101a of the beam body can be controlled within the tolerance range. Figure 5 The shape shown in Figure C

[0055] S4, punching, trimming, shaping the integrated circumferential flange 102. After completing this step, the product is Figure 5 The shape shown in Figure D

[0056] Punching includes punching the top surface and the side surface 101a of the beam body 011. Trimming refers to cutting off excess material edges.

[0057] By shaping the integrated circumferential flange 102, the face difference of the flange can be adjusted to within the tolerance range, especially when the above-mentioned distance T is greater than the thickness of the sheet 300, the face difference of the integrated circumferential flange 102 formed is larger and needs to be shaped after forming.

[0058] Tests and finite element analysis show that the U-shaped beam 100 formed using the above-mentioned stamping die 200 and forming method has a thinning rate reduced to about 10%, which is far lower than the 20% thinning rate required by the product. The cracking rate is also reduced from 30% to about 0.01%. The product qualification rate is significantly improved and the production cost is significantly reduced.

[0059] The principles and implementation methods of the present application have been described above using specific examples. The description of the above embodiments is only intended to help understand the method and core concept of the present application. It should be noted that for those skilled in the art, without departing from the principles of the present application, various improvements and modifications may be made to the present application, and such improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A stamping die, characterized in that: The stamping die (200) comprises: An upper die assembly, the upper die assembly comprising a die insert (201) arranged in the longitudinal direction, the die insert (201) having a concave cross-section; A lower die assembly, the lower die assembly comprising a punch insert (202), a projection of the punch insert (202) on a horizontal plane and a projection of the die insert (201) on a horizontal plane being staggered in the longitudinal direction, the punch insert (202) being arranged close to an end face of the die insert (201) and spaced apart from the end face by a distance T, the distance T being greater than a thickness of a sheet material (300) currently used in production, and the distance T being equal to twice the thickness of the sheet material (300) currently used in production; The male mold insert (202) includes a molding portion (202b); the transverse distance between the two side edges of the cross section of the molding portion (202b) and the vertical center line (Z) of the molding portion (202b) gradually decreases from bottom to top, so that the cross section of the molding portion (202b) is in a shape with a larger bottom and a smaller top; the projections of the two corners of the mold cavity of the female mold insert (201) on the transverse plane are correspondingly arranged above the projections of the two side edges of the cross section of the molding portion (202b) on the transverse plane, the cross section of the molding portion (202b) is in an isosceles trapezoid, and the range of the angle α between the two side edges of the isosceles trapezoid and the longitudinal center line (Z) of the molding portion (202b) is: 20°≤α≤45°; The upper mold assembly further includes an upper mold movable core, and the lower mold assembly further includes a lower mold movable core (203). The elasticity of the lower mold movable core (203) is greater than that of the upper mold movable core.

2. The stamping die according to claim 1, characterized in that: The male mold insert (202) includes a base portion (202a), and the forming portion (202b) is connected above the base portion (202a).

Images