A three-step double-door automobile front door inner panel stamping process

Abstract

The present application relates to a three-step double-door automobile front door inner panel stamping process, which belongs to the field of passenger car body manufacturing technology, and includes the following steps: the first drawing step, the front door inner panel sheet is placed in the drawing die, and the drawing die uses the concave die and the pressure ring to press the front door inner panel sheet, and then the concave die moves downward to stamp the front door inner panel sheet into a wavy front door inner panel blank with an upward convex middle and concave on both sides; the concave die continues to move downward, and with the cooperation of the concave die and the punch, the front door inner panel blank is drawn at one time into a front door inner panel drawn part with two front door inner panel profiles of a preset shape, an edge flange edge and a pressure surface, and the two front door inner panel profiles are symmetrically arranged and are counter-jointed on the window frame side. The present application optimizes the two-step drawing process into a one-step drawing process, which improves the processing efficiency of the product and reduces the production cost.

Description

Technical Field

[0001] The present application relates to the technical field of passenger car body manufacturing, and in particular to a three-step double-door automobile front door inner panel stamping process. Background Art

[0002] The front door inner panel is a typical large-scale covering part of the white body of a car. The stamping of this part has the manufacturing characteristics of high drawing depth, drastic shape changes, and complex stamping process. It often has quality defects such as wrinkling, cracking and springback. In addition, with the increasingly fierce competition in the automobile market, the pressure on reducing costs is increasing. Especially in the field of stamping, improving material utilization has become the most important factor in reducing manufacturing costs.

[0003] Regarding the forming technology of the front door inner panel, although domestic enterprises have also begun the process technology development of the front door inner panel and have mastered some key technologies, they currently mainly adopt the process methods of single-piece forming drawing and left-right closed-end drawing. Both of the above-mentioned drawing processes have certain disadvantages.

[0004] In the related technology, the depth of the front door inner panels of traditional cars varies due to the design of the car models. When the depth is deep, it will cause difficulties in the stamping process. For parts with deep door inner panels, the traditional technical solution requires a four-step stamping process, namely, the first step is the first drawing, the second step is the second drawing; the third step is punching and trimming; the fourth step is oblique punching and flanging.

[0005] However, the prior art uses a four-step stamping process, which has many processing steps, a large number of molds, high investment costs, and high processing energy consumption, resulting in high parts costs. In addition, during the four-step stamping process, a press equipment or a mold is required to provide a clamping force during the second drawing. When a press equipment is used to provide the clamping force, a hydraulic cushion or an air cushion needs to be added, and the equipment investment increases. When a mold is used to provide the clamping force, a nitrogen cylinder needs to be arranged in the mold. The mold is large in size, and the nitrogen cylinder is easily damaged, which has a high safety risk and a high spare parts cost.

[0006] In order to solve the problem that the front door inner panel parts are deep and difficult to form by one-time drawing, the existing technology also adopts the method of designing parts by parts, dividing the front door inner panel into two parts, the front side of the front door inner panel and the rear side of the front door inner panel. The front side of the door inner panel and the rear side of the front door inner panel are drawn separately and then connected into a whole by welding to reduce the drawing depth of the front door inner panel parts and ensure the formability.

[0007] However, the above-mentioned method of designing parts by parts increases the number of parts and the investment in molds. The increase in parts increases the total number of processing steps, resulting in increased processing costs. The addition of welding steps leads to poor dimensional accuracy of the front door inner panel and reduced material utilization, resulting in increased vehicle costs. Summary of the invention

[0008] The embodiment of the present application provides a three-step double-door automobile front door inner panel stamping process to solve the problem that automobile front door inner panels are difficult to be drawn and formed in one time in the related art, resulting in a large number of processing steps, a large number of molds, high investment costs, high processing energy consumption, low efficiency, and high parts costs.

[0009] The present application provides a three-step double-door automobile front door inner panel stamping process, comprising the following steps:

[0010] In the first drawing process, the front door inner panel sheet is placed in the drawing die. After the drawing die uses the concave die and the blank holder to press the front door inner panel sheet, the concave die moves downward to punch the front door inner panel sheet into a wavy front door inner panel blank with a convex middle and concave sides;

[0011] The die continues to move downward, and with the cooperation of the die and the punch, the front door inner panel blank is drawn into a front door inner panel drawn part with two front door inner panel surfaces of preset shapes, an edging flange edge and a pressing surface. The two front door inner panel surfaces are symmetrically arranged and are butted against each other on the window frame side.

[0012] In some embodiments: a first convex surface convex upward is formed by punching the middle of the pressing surface near the hinge side of the front door inner panel profile, and first concave surfaces concave downward are formed on both sides of the first convex surface, and the height difference between the crest of the first convex surface and the trough of the first concave surface is 40-50mm;

[0013] The first convex surface and the first concave surface are connected by a first circular arc transition section, the radius of the first convex surface is 495-505 mm, the radius of the first concave surface is 1450-1550 mm, and the radius of the first circular arc transition section is 950-1050 mm.

[0014] In some embodiments: a second convex surface convex upwardly is formed by punching the middle of the pressing surface close to the door lock side of the front door inner panel profile, and second concave surfaces concave downwardly are formed on both sides of the second convex surface, and the height difference between the crest of the second convex surface and the trough of the second concave surface is 50-60mm;

[0015] The second convex surface and the second concave surface are connected by a second circular arc transition section, the radius of the second convex surface is 195-205mm, the radius of the second concave surface is 1450-1550mm, and the radius of the second circular arc transition section is 950-1050mm.

[0016] In some embodiments: the two front door inner panel profiles are drawn at the jointed parts near the door lock side with two symmetrically arranged process supplementary slopes, the process supplementary slopes are inclined downward and toward the front door inner panel profile, and the overlap between the process supplementary slopes and the front door inner panel profile is provided with a transition fillet, and the radius of the transition fillet is 8 mm;

[0017] The side wall between the two symmetrically arranged process supplementary slopes is drawn with a first step and a second step connected to each other, the height of the first step is greater than the second step, the first step includes a first convex fillet with a radius of R15mm, a first concave fillet with a radius of R20mm, and the draft angle of the first step is 15°;

[0018] The second step includes a second convex fillet with a radius of R35 mm, a second concave fillet with a radius of R10 mm, and a draft angle of the second step is 15°.

[0019] In some embodiments: a process supplementary side wall is drawn at the joint part of the two front door inner panel profiles near the hinge side, a third convex fillet with a radius of 40 mm is provided at the overlap of the process supplementary side wall and the front door inner panel profile, a third concave fillet with a radius of 20 mm is provided at the overlap of the process supplementary side wall and the pressing surface, and the draft angle of the process supplementary side wall is 15°;

[0020] The top of the process-supplemented side wall is drawn with a mating plane, and a downward concave wrinkle suction rib is provided on the mating plane. The length of the wrinkle suction rib is 40mm, the width is 20mm, and the depth is 3.5mm. A triangular inclined surface is drawn at the overlap between the mating plane and the front door inner panel surface, and a fourth concave fillet for forming tensile strain and compressive strain is drawn on the triangular inclined surface, and the radius of the fourth concave fillet is 10mm.

[0021] In some embodiments: the fillet radius between the edge of the hemming flange on the two front door inner panel profiles close to the door lock side and the pressing surface is 10 mm, and the pressing surfaces on the two front door inner panel profiles close to the door lock side are provided with convex features and concave features, the fillet radius of the concave features is 6-8 mm, and the fillet radius of the convex features is 15 mm;

[0022] The two front door inner panel profiles are drawn with a third convex fillet with a radius of 20 mm and a fifth concave fillet with a radius of 10 mm at the corners near the door sill, and the side wall draft angle between the third convex fillet and the fifth concave fillet is 35°-40°.

[0023] In some embodiments: the front door inner panel is formed by welding a first panel and a second panel, the thickness of the first panel is greater than the thickness of the second panel, the first panel is located on the hinge side, and the second panel is located on the door lock side;

[0024] The first panels of the two front door inner panel profiles close to the door sill are provided with a sixth concave rounded corner with a radius of 18 mm, and the second panels of the two front door inner panel profiles close to the door sill are provided with a seventh concave rounded corner with a radius of 10 mm.

[0025] In some embodiments: the first sheet material of the two front door inner panel surfaces close to the hinge side is provided with a fourth convex rounded corner with a radius of 10 mm and an eighth concave rounded corner with a radius of 10 mm, and the height of the pressing surface of the two front door inner panel surfaces close to the hinge side is lower than the height of the edging flange edge of the two front door inner panel surfaces close to the hinge side.

[0026] In some embodiments: it also includes a second trimming, shaping, straight punching and slitting process, placing the front door inner panel drawn part into the trimming, shaping, straight punching and slitting mold, and after the trimming, shaping, punching and slitting mold uses a pressing plate to press the front door inner panel drawn part, a trimming insert is used to cut off the pressing surface outside the edging flange, and a shaping insert is used to shape the fillet of the edging flange. The fillet radius of the shaping insert is 6mm, and a straight punch is used to punch out multiple through holes on the front door inner panel drawn part, and finally the two front door inner panel surfaces are cut to form a front door inner panel slit part.

[0027] In some embodiments: it also includes a third straight punching, oblique punching, and flanging process, placing the front door inner panel cut pieces into the straight punching, oblique punching, and flanging molds, and the straight punching, oblique punching, and flanging molds perform straight punching and oblique punching on the front door inner panel cut pieces, and flanging the edges of one or more through holes formed by the straight punching and oblique punching to finally form the front door inner panel finished pieces.

[0028] The beneficial effects of the technical solution provided by this application include:

[0029] The embodiment of the present application provides a three-step double-door automobile front door inner panel stamping process. In the three-step double-door automobile front door inner panel stamping process of the present application, the front door inner panel sheet is placed into a drawing die in the first drawing process. After the drawing die presses the front door inner panel sheet with a die and a pressure ring, the die moves downward to stamp the front door inner panel sheet into a wavy front door inner panel blank with an upward convex middle portion and concave sides; the die continues to move downward, and with the cooperation of the die and the punch, the front door inner panel blank is drawn at one time into a front door inner panel drawn part with two front door inner panel profiles, an edging flange edge and a pressure surface having a preset shape. The two front door inner panel profiles are symmetrically arranged and are opposed to each other on the window frame side.

[0030] Therefore, in the three-step double-door automobile front door inner panel stamping process of the present application, before drawing the two front door inner panel shapes, the front door inner panel sheet is first pressed by the die and the blank holder, and then the die moves downward to stamp the front door inner panel sheet into a wavy front door inner panel blank with an upward convex middle and concave on both sides. An upward convex feature is formed in the middle of the front door inner panel blank, and downward concave features are formed on both sides of the upward convex feature in the middle, and the upward convex feature and the downward concave feature are consistent with the drawing depth trend of the double-door automobile front door inner panel.

[0031] The upward convex feature and the downward concave feature are used to control the uniform change of the drawing depth of the front door inner panel parts of the double-door automobile and the shallow drawing depth, and can form the front door inner panel drawn parts with two front door inner panel profiles, hemming flange edges and pressing surfaces of a preset shape at one time. The present application optimizes the two-step drawing process into a one-step drawing process, improves the processing efficiency of the product, and reduces the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 This is a structural stereogram of the front door inner panel drawn part of the embodiment of the present application;

[0034] Figure 2 This is a top view of the structure of the front door inner panel drawn part of the embodiment of the present application;

[0035] Figure 3 for Figure 2 The cross section along the AA direction;

[0036] Figure 4 for Figure 2 The cross section along the BB direction;

[0037] Figure 5 for Figure 2 A partial enlarged view of the middle A;

[0038] Figure 6 for Figure 5 The cross section along CC direction;

[0039] Figure 7 for Figure 2 A partial enlarged view of point B in the middle;

[0040] Figure 8 for Figure 2 The cross section along the DD direction;

[0041] Fig. 9 for Figure 2 The cross section along the EE direction;

[0042] Fig.10 for Figure 2 The cross section along the FF direction;

[0043] Fig.11 This is a top view of the structure of the front door inner panel cutting piece of the embodiment of the present application;

[0044] Fig.12 This is a structural stereogram of the front door inner panel cutting piece of the embodiment of the present application;

[0045] Fig.13 This is a top view of the structure of the finished front door inner panel of the embodiment of the present application;

[0046] Fig.14 This is a structural stereogram of the finished front door inner panel of the embodiment of the present application;

[0047] Fig.15 It is a schematic diagram of the partial structure of the trimming, shaping, straight punching and slitting dies of the embodiment of the present application.

[0048] Reference numerals:

[0049] 100, front door inner panel drawing part; 101, front door inner panel profile; 102, hemming flange edge; 103, pressing surface; 104, first convex curved surface; 105, first concave curved surface; 106, first arc transition section; 107, second convex curved surface; 108, second concave curved surface; 109, second arc transition section; 110, process supplement slope; 111, transition fillet; 112, first convex fillet; 113, first concave fillet; 114, second convex fillet; 115, second concave fillet; 116, process supplement side wall; 117, third convex fillet ; 118, third concave fillet; 119, wrinkle suction concave rib; 120, triangular inclined plane; 121, fourth concave fillet; 122, raised feature; 123, concave feature; 124, third convex fillet; 125, fifth concave fillet; 126, sixth concave fillet; 127, seventh concave fillet; 128, welding line control rib; 129, fourth convex fillet; 130, eighth concave fillet; 200, front door inner panel cut piece; 201, trimming insert; 202, shaping insert; 203, press plate; 204, punch; 300, front door inner panel finished product. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0051] The embodiment of the present application provides a three-step double-door automobile front door inner panel stamping process, which can solve the problem in the related art that automobile front door inner panels are difficult to be drawn and formed in one time, resulting in a large number of processing steps, a large number of molds, high investment costs, high processing energy consumption, low efficiency, and high parts costs.

[0052] See also Figure 1 and Figure 2 As shown, the embodiment of the present application provides a three-step double-door automobile front door inner panel stamping process, comprising the following steps:

[0053] In the first drawing process, the front door inner panel sheet is placed into the drawing die. The front door inner panel sheet is a rectangular flat steel plate cut from a 0.7-1.4mm thick steel coil material. The front door inner panel sheet is preferably a tailored plate welded from a 1.4mm thick first sheet and a 0.7mm thick second sheet. After the drawing die uses the concave die and the blank holder to press the front door inner panel sheet, the concave die moves downward to punch the front door inner panel sheet into a wavy front door inner panel blank with a convex middle and concave sides. The concave die and the blank holder squeeze the front door inner panel sheet into a wavy structure with a convex middle and concave sides. The convex feature in the middle is the part where the two front door inner panel profiles are formed by subsequent drawing, and the concave features on both sides are the drawing parts where the two front door inner panel profiles are formed by subsequent drawing.

[0054] Since the joining parts of the two joined front door inner panel profiles and the drawn parts of the two joined front door inner panel profiles are both parts with a deep drawing depth, these parts are most likely to produce defects such as wrinkles and cracks. In the embodiment of the present application, the joining parts and the front door inner panel profile parts are first stamped to form a wavy structure with an upward convex middle and concave sides, which is consistent with the trend of the drawing depth of the front door inner panel of the double-door automobile. The features of the front door inner panel blank with an upward convex middle and concave sides are used to control the uniform change of the drawing depth of the front door inner panel parts of the double-door automobile and the shallow drawing depth, so that it can be drawn and formed in one time, so as to reduce the drawing depth of the front door inner panel sheet material in this part and ensure one-time drawing and forming.

[0055] The die continues to move downward, and with the cooperation of the die and the punch, the front door inner panel blank is drawn into a front door inner panel drawn part 100 having two front door inner panel profiles 101 of preset shapes, an edging flange edge 102 and a pressing surface 103. The two front door inner panel profiles 101 are symmetrically arranged and matched on the window frame side.

[0056] In the three-step double-door automobile front door inner panel stamping process of the embodiment of the present application, before drawing the two front door inner panel profiles 101, the front door inner panel sheet is first pressed by a concave die and a blank holder, and then the concave die moves downward to stamp the front door inner panel sheet into a wavy front door inner panel blank with an upward convex middle and concave sides. An upward convex feature is formed in the middle of the front door inner panel blank, and downward concave features are formed on both sides of the upward convex feature in the middle, and the upward convex feature and the downward concave feature are consistent with the drawing depth trend of the double-door automobile front door inner panel.

[0057] The upward convex feature and the downward concave feature are used to control the uniform change of the drawing depth of the front door inner panel parts of the double-door automobile and the shallow drawing depth, and the front door inner panel drawn part 100 with two front door inner panel profiles 101, the hemming flange 102 and the pressing surface 103 of the preset shape can be formed by one-time drawing. The present application optimizes the two-step drawing process into a one-step drawing process, improves the processing efficiency of the product, and reduces the production cost.

[0058] See also Figure 2 and Figure 3 As shown, the embodiment of the present application provides a three-step double-door automobile front door inner panel stamping process, in which the middle of the pressing surface 103 near the hinge side of the front door inner panel profile 101 (the hinge side is the part where the front door inner panel and the body are connected through the door hinge) is stamped to form a first convex surface 104 that bulges upward. First concave surfaces 105 that are concave downward are formed on both sides of the first convex surface 104, and the height difference between the wave crest of the first convex surface 104 and the wave trough of the first concave surface 105 is 40-50mm, and the height difference between the wave crest of the first convex surface 104 and the wave trough of the first concave surface 105 is further preferably 45mm.

[0059] The first convex surface 104 and the first concave surface 105 are connected by a first arc transition section 16. The radius of the first convex surface 104 is 495-505 mm, and the radius of the first convex surface 104 is further preferably 500 mm. The radius of the first concave surface 105 is 1450-1550 mm, and the radius of the first concave surface 105 is further preferably 1500 mm. The radius of the first arc transition section 106 is 950-1050 mm, and the radius of the first arc transition section 106 is further preferably 1000 mm.

[0060] In the embodiment of the present application, a first convex surface 104 convex upward is formed by stamping in the middle of the pressing surface 103 near the hinge side of the front door inner panel profile 101, and first concave surfaces 105 concave downward are formed on both sides of the first convex surface 104. The first convex surface 104 is used for drawing to form the joint parts of the two front door inner panel profiles 101, and the first concave surface 105 is used for drawing to form the two front door inner panel profiles 101. The height difference between the crest of the first convex surface 104 and the trough of the first concave surface 105 is preferably 45mm. If the height difference between the crest of the first convex surface 104 and the trough of the first concave surface 105 is too small, there will be a risk of cracking. If the height difference between the crest of the first convex surface 104 and the trough of the first concave surface 105 is too large, there will be a risk of wrinkling.

[0061] In the embodiment of the present application, the radius of the first convex surface 104 is further preferably 500 mm, the radius of the first concave surface 105 is preferably 1500 mm, and the radius of the first arc transition section 106 is preferably 1000 mm. If the radius of the first convex surface 104 is too large, there will be a risk of wrinkling, and if the radius of the first convex surface 104 is too small, there will be a risk of cracking. If the radius of the first concave surface 105 is too large, there will be a risk of cracking, and if the radius of the first concave surface 105 is too small, there will be a risk of wrinkling. If the radius of the first arc transition section 106 is too large, there will be a risk of cracking, and if the radius of the first arc transition section 106 is too small, there will be a risk of wrinkling.

[0062] See also Figure 2 and Figure 4 As shown, the embodiment of the present application provides a three-step double-door front door inner panel stamping process for automobiles, wherein the three-step double-door front door inner panel stamping process is to stamp a second convex surface 107 protruding upwards in the middle of the pressing surface 103 near the door lock side of the front door inner panel profile 101 (the door lock side is the part where the front door inner panel and the vehicle body are connected through the door lock). Second concave surfaces 108 concave downwards are formed on both sides of the second convex surface 107, and the height difference between the wave crest of the second convex surface 107 and the wave trough of the second concave surface 108 is 50-60mm, and the height difference between the wave crest of the second convex surface 107 and the wave trough of the second concave surface 108 is further 55mm.

[0063] The second convex surface 107 and the second concave surface 108 are connected by a second arc transition section 109. The radius of the second convex surface 107 is 195-205 mm, and the radius of the second convex surface 107 is further preferably 200 mm. The radius of the second concave surface 108 is 1450-1550 mm, and the radius of the second concave surface 108 is further preferably 1500 mm. The radius of the second arc transition section 109 is 950-1050 mm, and the radius of the second arc transition section 109 is further preferably 1000 mm.

[0064] In the embodiment of the present application, a second convex surface 107 convex upward is formed by stamping in the middle of the pressing surface 103 near the door lock side of the front door inner panel profile 101, and second concave surfaces 108 concave downward are formed on both sides of the second convex surface 107. The second convex surface 107 is used for drawing to form the joint parts of the two front door inner panel profiles 101, and the second concave surface 108 is used for drawing to form the two front door inner panel profiles 101. The height difference between the crest of the second convex surface 107 and the trough of the second concave surface 108 is preferably 55mm. If the height difference between the crest of the second convex surface 107 and the trough of the second concave surface 108 is too small, there will be a risk of cracking. If the height difference between the crest of the second convex surface 107 and the trough of the second concave surface 108 is too large, there will be a risk of wrinkling.

[0065] In the embodiment of the present application, the radius of the second convex surface 107 is further preferably 200 mm, the radius of the second concave surface 108 is preferably 1500 mm, and the radius of the second arc transition section 109 is preferably 1000 mm. If the radius of the second convex surface 107 is too large, there will be a risk of wrinkling, and if the radius of the second convex surface 107 is too small, there will be a risk of cracking. If the radius of the second concave surface 108 is too large, there will be a risk of cracking, and if the radius of the second concave surface 108 is too small, there will be a risk of wrinkling. If the radius of the second arc transition section 109 is too large, there will be a risk of cracking, and if the radius of the second arc transition section 109 is too small, there will be a risk of wrinkling.

[0066] See also Figure 2 , Figure 5 and Figure 6 As shown, an embodiment of the present application provides a three-step double-door automobile front door inner panel stamping process, wherein the three-step double-door automobile front door inner panel stamping process has two symmetrically arranged process supplementary slopes 110 drawn at the splicing portion of the two front door inner panel profiles 101 close to the door lock side, the process supplementary slopes 110 are inclined downward and toward the front door inner panel profile 101, and a transition fillet 111 is provided at the overlap between the process supplementary slope 110 and the front door inner panel profile 101, and the radius of the transition fillet 111 is 8 mm.

[0067] The sidewall between the two symmetrically arranged process supplementary slopes 110 is drawn with a first step and a second step connected to each other, the height of the first step is greater than the second step, the first step includes a first convex fillet 112 with a radius of R15mm, a first concave fillet 113 with a radius of R20mm, and the draft angle of the first step is 15°. The second step includes a second convex fillet 114 with a radius of R35mm, a second concave fillet 115 with a radius of R10mm, and the draft angle of the second step is 15°.

[0068] The joint part of the two front door inner panel profiles 101 near the door lock side of the embodiment of the present application is in a "J"-shaped structure. The process supplementation has a high risk of cracking in the corner area where this part and the part meet, which leads to molding failure. The two front door inner panel profiles 101 near the door lock side have two symmetrically arranged process supplementation slopes 110 during drawing, and the inclination angle of the process supplementation slopes 110 is 55°. The side wall between the two symmetrically arranged process supplementation slopes 110 is drawn with a first step and a second step connected to each other, which can effectively eliminate the contradiction between cracking and wrinkling at this point.

[0069] See also Figure 2 and Figure 7 As shown, the embodiment of the present application provides a three-step double-door automobile front door inner panel stamping process, in which a process supplementary side wall 116 is drawn at the joint part of the two front door inner panel profiles 101 close to the hinge side. A third convex fillet 117 with a radius of 40 mm is provided at the overlap of the process supplementary side wall 116 and the front door inner panel profile 101, and a third concave fillet 118 with a radius of 20 mm is provided at the overlap of the process supplementary side wall 116 and the pressing surface 103, and the draft angle of the process supplementary side wall 116 is 15°.

[0070] A counter-joint plane is drawn at the top of the process supplementary side wall 116, and a downwardly concave wrinkle absorbing rib 119 is provided on the counter-joint plane. The length of the wrinkle absorbing rib 119 is 40 mm, the width is 20 mm, and the depth is 3.5 mm. The wrinkle absorbing rib 119 is used to prevent the counter-joint plane from wrinkling. A triangular inclined plane 120 is drawn at the overlap between the counter-joint plane and the front door inner panel profile 101. A fourth concave fillet 121 for forming tensile strain and compressive strain is drawn on the triangular inclined plane 120, and the radius of the fourth concave fillet 121 is 10 mm.

[0071] Since the outer side of the two front door inner panel surfaces 101 near the hinge side is prone to cracking risk, and the inner side is prone to wrinkling risk. In the outer area of ​​the embodiment of the present application, the design process supplements the third convex fillet 117 with a radius of 40mm, the third concave fillet 118 with a radius of 20mm, and the side wall draft angle of 15°, which prevents cracking while ensuring material utilization. When the process joint part is close to one side (inside) of the product, when the sheet metal is subjected to stress during forming, it is in a state of tensile and compressive strain, and wrinkling defects are prone to occur in the direction of the compressive strain state.

[0072] A triangular slope 120 is designed at the joint part of the two front door inner panel profiles 101 near the hinge side to change the shape and line length of the side wall area, thereby changing the strain state of the area. The triangular slope 120 is connected to the side wall and the bottom surface through convex fillets on all sides to ensure that there are no sharp points that change dramatically. The fourth concave fillet 121 is used inside the triangular slope 120 to adjust the line length in the tensile strain and compressive strain directions. In the tensile strain direction, the line length is shortened by 16% when the fourth concave fillet 121 is used to adjust the front and back, eliminating the risk of cracking in this direction. In the compressive stress direction, the fourth concave fillet 121 is used to adjust the up and down, and the line length increases by 20%, eliminating the risk of wrinkling in this direction.

[0073] See also Figure 2 and Figure 8 and Fig. 9 As shown, the embodiment of the present application provides a three-step double-door automobile front door inner panel stamping process, in which the fillet radius between the hemming flange edge 102 and the pressing surface 103 of the two front door inner panel profiles 101 close to the door lock side is 10mm. The pressing surface of the two front door inner panel profiles 101 close to the door lock side is provided with a convex feature 122 and a concave feature 123, the fillet radius of the concave feature 123 is 6-8mm, and the fillet radius of the convex feature 122 is 15mm.

[0074] The depth of the area between the hemming flange 102 and the pressing surface 103 on the two front door inner panel profiles 101 near the door lock side varies between about 145-153mm. If the parts are drawn in place at one time, the problem of parts cracking will occur. During the process design, the fillet radius between the hemming flange 102 and the pressing surface 103 on the two front door inner panel profiles 101 near the door lock side is enlarged from R6mm to R10mm. The pressing surface on the two front door inner panel profiles 101 near the door lock side is provided with a raised feature 122 and a concave feature 123 to control the drawing depth of the parts here to be consistent and prevent cracking.

[0075] See also Figure 1 and Figure 2 As shown, the corners of the two front door inner panel profiles 101 close to the door sill are drawn with a third convex fillet 124 with a radius of 20mm and a fifth concave fillet 125 with a radius of 10mm, and the side wall draft angle between the third convex fillet 124 and the fifth concave fillet 125 is 35°-40°. The corners of the two front door inner panel profiles 101 close to the door sill have a large difference in material flow resistance with both sides, and the material flow speed is lower than that on both sides, which makes it easy for material to accumulate and cause wrinkling of the parts. Here, the third convex fillet 124 is designed to be R20mm, the fifth concave fillet 125 is designed to be R10mm, and the side wall draft angle is 35° to reduce the resistance to material inflow.

[0076] See also Figure 1 and Figure 2 As shown, the embodiment of the present application provides a three-step double-door automobile front door inner panel stamping process, in which the front door inner panel sheet material of the three-step double-door automobile front door inner panel stamping process is welded by a first sheet material of 1.4 mm thickness and a second sheet material of 0.7 mm thickness, the first sheet material is located on the hinge side, and the second sheet material is located on the door lock side. Welding line control ribs 128 are provided on both sides of the welding line of the first sheet material and the second sheet material, and the welding line control ribs 128 are used to control the offset problem of the welding line during the drawing process. The welding line control ribs 128 are symmetrically arranged along the initial position of the welding line, and the center line of the welding line control ribs 128 is 175 mm away from the initial position of the welding line. The welding line control ribs 128 are 170 mm away from the sheet line on the side close to the sheet material; by adjusting the parameters of the welding line control ribs 128, the position of the welding line after forming can be controlled.

[0077] The first sheet material of the two front door inner panel profiles 101 near the threshold side is provided with a sixth concave fillet 126 with a radius of 18 mm, and the second sheet material of the two front door inner panel profiles 101 near the threshold side is provided with a seventh concave fillet 127 with a radius of 10 mm. Since the thickness of the first sheet material on the hinge side is greater than the thickness of the second sheet material on the door lock side, in order to maintain the uniformity of material inflow, the first sheet material near the threshold side is provided with a sixth concave fillet 126 with a radius of 18 mm, and the second sheet material near the threshold side is provided with a seventh concave fillet 127 with a radius of 10 mm, so as to ensure that the flow resistance of the first sheet material is less than the flow resistance of the second sheet material.

[0078] See also Figure 1 , Figure 2 and Fig.10 As shown, the first sheet material of the two front door inner panel profiles 101 near the hinge side is provided with a fourth convex fillet 129 with a radius of 10mm and an eighth concave fillet 130 with a radius of 10mm, and the height of the pressing surface 103 of the two front door inner panel profiles 101 near the hinge side is lower than the height of the hemming flange 102 of the two front door inner panel profiles 101 near the hinge side. The first sheet material of the two front door inner panel profiles 101 near the hinge side is a thick sheet material, and the part drawing depth is about 152mm, and the depth variation is relatively uniform. Here, the root fillet of the hemming flange 102 is enlarged to R10mm for drawing, the fourth convex fillet 129 is designed to be R10mm, and the eighth concave fillet 130 is designed to be R10mm. Here, the height of the pressing surface 103 is only two millimeters lower than the hemming flange 102, ensuring that the hemming flange is drawn.

[0079] See also Figures 11 to 15As shown, the embodiment of the present application provides a three-step double-door automobile front door inner panel stamping process, which also includes a second trimming, shaping, straight punching, and slitting process, in which the front door inner panel drawn part 100 is placed in a trimming, shaping, straight punching, and slitting die, and the trimming, shaping, punching, and slitting die uses a press plate 203 to press the front door inner panel drawn part 100, and then uses a trimming insert 201 to cut off the press surface 103 outside the hemming flange 102. The shaping insert 202 is used to shape the fillet of the hemming flange 102, and the fillet radius of the shaping insert 202 is 6mm, and the fillet radius of the hemming flange 102 is 10mm to 6mm. A straight punch 204 is used to punch out a plurality of through holes on the front door inner panel drawn piece 100 , and finally two front door inner panel profiles 101 are cut to form the front door inner panel cut pieces 200 .

[0080] It also includes a third straight punching, oblique punching, and flanging process, in which the front door inner panel cut piece 200 is placed into the straight punching, oblique punching, and flanging molds, and the straight punching, oblique punching, and flanging molds perform straight punching and oblique punching on the front door inner panel cut piece, and flanging the edges of one or more through holes formed by the straight punching and oblique punching, to finally form a front door inner panel finished product 300.

[0081] How it works

[0082] The embodiment of the present application provides a three-step double-door automobile front door inner panel stamping process. In the three-step double-door automobile front door inner panel stamping process of the present application, the front door inner panel sheet is placed into a drawing die in the first drawing process. After the drawing die presses the front door inner panel sheet with a die and a pressure ring, the die moves downward to stamp the front door inner panel sheet into a wavy front door inner panel blank with an upward convex middle portion and concave on both sides. The die continues to move downward, and with the cooperation of the die and the punch, the front door inner panel blank is drawn at one time into a front door inner panel drawn part 100 with two front door inner panel profiles 101 of preset shapes, an edging flange edge 102 and a pressing surface 103. The two front door inner panel profiles 101 are symmetrically arranged and are opposed to each other on the window frame side.

[0083] Therefore, in the three-step double-door automobile front door inner panel stamping process of the present application, before drawing the two front door inner panel shapes, the front door inner panel sheet is first pressed by the die and the blank holder, and then the die moves downward to stamp the front door inner panel sheet into a wavy front door inner panel blank with an upward convex middle and concave on both sides. An upward convex feature is formed in the middle of the front door inner panel blank, and downward concave features are formed on both sides of the upward convex feature in the middle, and the upward convex feature and the downward concave feature are consistent with the drawing depth trend of the double-door automobile front door inner panel.

[0084] The upward convex feature and the downward concave feature are used to control the uniform change of the drawing depth of the front door inner panel parts of the double-door automobile and the shallow drawing depth, and the front door inner panel drawn part 100 with two front door inner panel profiles 101, the hemming flange 102 and the pressing surface 103 of the preset shape can be formed by one-time drawing. The present application optimizes the two-step drawing process into a one-step drawing process, improves the processing efficiency of the product, and reduces the production cost.

[0085] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0086] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0087] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A three-step double-door automobile front door inner panel stamping process, characterized in that: The following steps are involved: In the first drawing process, the front door inner panel sheet is placed in the drawing die. After the drawing die uses the concave die and the blank holder to press the front door inner panel sheet, the concave die moves downward to punch the front door inner panel sheet into a wavy front door inner panel blank with a convex middle and concave sides; The die continues to move downward, and the front door inner panel blank is drawn at one time into a front door inner panel drawn part (100) having two front door inner panel profiles (101) of a preset shape, an edge flange (102) and a pressing surface (103) under the cooperation of the die and the punch, wherein the two front door inner panel profiles (101) are symmetrically arranged and butted against each other on the window frame side; The two front door inner panel profiles (101) are stretched to have two symmetrically arranged process supplementary slopes (110) at the jointed parts close to the door lock side, the process supplementary slopes (110) are inclined downward and towards the front door inner panel profile (101), and a transition fillet (111) is provided at the overlap between the process supplementary slope (110) and the front door inner panel profile (101), and the radius of the transition fillet (111) is 8 mm; The side wall between the two symmetrically arranged process supplementary slopes (110) is drawn to have a first step and a second step connected to each other, the height of the first step is greater than the second step, the first step comprises a first convex fillet (112) with a radius of R15 mm, a first concave fillet (113) with a radius of R20 mm, and a draft angle of the first step is 15°; The second step includes a second convex fillet (114) with a radius of R35 mm, a second concave fillet (115) with a radius of R10 mm, and a draft angle of the second step is 15°.

2. A three-step double-door automobile front door inner panel stamping process as claimed in claim 1, characterized in that: A first convex curved surface (104) convexing upward is formed by punching in the middle of the pressing surface (103) close to the hinge side of the front door inner panel profile (101), and first concave curved surfaces (105) concave downward are respectively formed on both sides of the first convex curved surface (104), and the height difference between the wave crest of the first convex curved surface (104) and the wave trough of the first concave curved surface (105) is 40-50 mm; The first convex surface (104) and the first concave surface (105) are connected via a first circular arc transition section (106); the radius of the first convex surface (104) is 495-505 mm, the radius of the first concave surface (105) is 1450-1550 mm, and the radius of the first circular arc transition section (106) is 950-1050 mm.

3. A three-step double-door automobile front door inner panel stamping process as claimed in claim 1, characterized in that: A second convex surface (107) convexing upward is formed by punching in the middle of the pressing surface (103) on the door lock side close to the front door inner plate profile (101), and second concave surfaces (108) concave downward are respectively formed on both sides of the second convex surface (107), and the height difference between the wave crest of the second convex surface (107) and the wave trough of the second concave surface (108) is 50-60 mm; The second convex surface (107) and the second concave surface (108) are connected via a second circular arc transition section (109); the radius of the second convex surface (107) is 195-205 mm, the radius of the second concave surface (108) is 1450-1550 mm, and the radius of the second circular arc transition section (109) is 950-1050 mm.

4. A three-step double-door automobile front door inner panel stamping process as claimed in claim 1, characterized in that: A process supplementary side wall (116) is drawn at the jointed portion of the two front door inner panel profiles (101) near the hinge side, a third convex fillet (117) with a radius of 40 mm is provided at the overlap between the process supplementary side wall (116) and the front door inner panel profile (101), a third concave fillet (118) with a radius of 20 mm is provided at the overlap between the process supplementary side wall (116) and the pressing surface (103), and a draft angle of the process supplementary side wall (116) is 15°; The top of the process supplementary side wall (116) is drawn with a counter-joined plane, and a downwardly concave wrinkle suction rib (119) is provided on the counter-joined plane, and the length of the wrinkle suction rib (119) is 40 mm, the width is 20 mm, and the depth is 3.5 mm. A triangular inclined surface (120) is drawn at the overlap between the counter-joined plane and the front door inner panel profile (101), and a fourth concave fillet (121) for forming tensile strain and compressive strain is drawn on the triangular inclined surface (120), and the radius of the fourth concave fillet (121) is 10 mm.

5. A three-step double-door automobile front door inner panel stamping process as claimed in claim 1, characterized in that: The fillet radius between the hemming flange edge (102) and the pressing surface (103) of the two front door inner panel profiles (101) close to the door lock side is 10 mm, and the pressing surface (103) of the two front door inner panel profiles (101) close to the door lock side is provided with a convex feature (122) and a concave feature (123), the fillet radius of the concave feature (123) is 6-8 mm, and the fillet radius of the convex feature (122) is 15 mm; The two front door inner panel profiles (101) are drawn at the corner positions near the door sill side to form a third convex fillet (124) with a radius of 20 mm and a fifth concave fillet (125) with a radius of 10 mm, and the side wall draft angle between the third convex fillet (124) and the fifth concave fillet (125) is 35°-40°.

6. A three-step double-door automobile front door inner panel stamping process as claimed in claim 1, characterized in that: The front door inner panel is formed by welding a first panel and a second panel, the thickness of the first panel is greater than the thickness of the second panel, the first panel is located on the hinge side, and the second panel is located on the door lock side; The first plate material of the two front door inner panel profiles (101) close to the door sill is provided with a sixth concave rounded corner (126) with a radius of 18 mm, and the second plate material of the two front door inner panel profiles (101) close to the door sill is provided with a seventh concave rounded corner (127) with a radius of 10 mm.

7. A three-step double-door automobile front door inner panel stamping process as claimed in claim 6, characterized in that: The first sheet material of the two front door inner panel profiles (101) close to the hinge side is provided with a fourth convex fillet (129) with a radius of 10 mm and an eighth concave fillet (130) with a radius of 10 mm, and the height of the pressing surface (103) of the two front door inner panel profiles (101) close to the hinge side is lower than the height of the edging flange edge (102) of the two front door inner panel profiles (101) close to the hinge side.

8. The three-step double-door automobile front door inner panel stamping process as claimed in claim 1, characterized in that: The method also includes a second trimming, shaping, straight punching and slitting step, wherein the front door inner panel drawn piece (100) is placed in a trimming, shaping, straight punching and slitting die, and the trimming, shaping, punching and slitting die uses a pressing plate (203) to press the front door inner panel drawn piece (100), and then uses a trimming insert (201) to cut off the pressing surface (103) outside the hemming flange edge (102), and uses a shaping insert (202) to shape the fillet of the hemming flange edge (102), wherein the fillet radius of the shaping insert (202) is 6 mm, and uses a straight punch (204) to punch out multiple through holes on the front door inner panel drawn piece (100), and finally cuts the two front door inner panel profiles (101) to form a front door inner panel slit piece (200).

9. A three-step double-door automobile front door inner panel stamping process as claimed in claim 8, characterized in that: The method also includes a third straight punching, oblique punching and flanging process, in which the front door inner panel cut piece (200) is placed in a straight punching, oblique punching and flanging mold, and the straight punching, oblique punching and flanging mold performs straight punching and oblique punching on the front door inner panel cut piece (200), and the edges of one or more through holes formed by the straight punching and oblique punching are flanging, so as to finally form a front door inner panel finished piece (300).

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