MXPA00003005A - Draw stamping die for stamping body panels for motor vehicles - Google Patents

Abstract

A method and apparatus for forming an exterior body panel for a motor vehicle. The method comprises mounting a sheet of metal material (16) in a die assembly, clamping first peripheral portion of the sheet of metal material between clamping surfaces of the die assembly (18), moving the clamping surfaces relative to a central die structure so as to deform the sheet metal over the central die structure, clamping second peripheral portion of the sheet of metal material between a die pad of the die assembly and the central die structure after the sheet metal is deformed over the central die structure, moving the clamping surfaces relative to the central die structure to stretch the sheet metal over the central die structure after the second peripheral portion of the sheet of metal material are clamped, and stamping the sheet of metal material between the central structure and an opposing die surface after the sheet metal has been stretched over the die structure so as to provide the sheet metal with a desired configuration.

Description

DRAWING MATRIX OF DRAWINGS FOR THROWING OF MOTOR VEHICLE BODY PANELS The present invention relates to die-cutting dies and methods for die-cutting metal sheets for motor vehicle body panels.

BACKGROUND OF THE INVENTION In art, it is known to form the metal sheet drawing and the die cutting thereof to form various metallic parts. In the conventional pattern forming or punching operations, the metal sheet is clamped on its periphery by clamps and then tensioned on a fixed structure of a punch, before it is punched out in a desired configuration. The tensioning of the metallic material before the die-cutting tempers by work to the material so that a stronger piece can be manufactured with less amount of required material.

Such technology has been implemented in the automotive industry, for example, for the manufacture of interior panels. However, until now, the drawing has been formed or the sheet metal die cut, which can be R? F .: 32912 - ^ used as exterior body panels has not been commercially successful. Specifically, pattern formation and punching operations have conventionally produced parts that are not suitable for use in applications that require "class A" finished surfaces, such as those required for the exterior panels of the bodies. With more specificity, the operations for forming patterns impart stress marks, scratches, and other irregularities to the part which does not make the part suitable as an exterior body panel.

BRIEF DESCRIPTION OF THE INVENTION The disadvantages of the prior art can be overcome by providing an assembly of a die-cutting die that can be used for the manufacture of exterior body panels.

According to one aspect of the invention, an assembly of a die-cutting die is provided for die-cutting metal sheet patterns in a press to form an exterior body panel for a motor vehicle. The assembly of the die consists of a first die assembly including a first die structure that engages a surface of the metal sheet during the die cutting operation. The first die assembly further includes a movable structure of peripheral clamps that are movable with respect to the first die structure and constructed and arranged to engage the first peripheral portion of the metal sheet. A second die assembly is provided and includes a second die structure having a central die surface that engages the opposite surface of the metal sheet during the punching operation. The second die structure includes a peripheral engaging surface constructed and arranged to cooperate there with the movable latch structure - of the first peripheral portion of the metal sheet. The second die assembly further includes a stepped die which is movable with respect to the second die structure. The mobile step die cooperates with the first structure to hold there the second peripheral portion of the metal sheet. The second die assembly is moveable by a press whereby its peripheral clamping surface cooperates with the structure of the movable clamp of the first die assembly to hold there the first peripheral portion of the metal sheet. The peripheral clamping surface and the structure of the movable clamp move with the first portions of the metal sheet held thereon to deform the metal sheet on the first central die structure. The stamping die is movable with respect to the second die structure and in the direction of the first die structure in such a manner as to hold the second portions of the metal sheet between the movable treading die and the first die structure after which the metal sheet is deformed on the first central structure of the die. The peripheral clamping surface and the mobile clamping structure can be moved to tension the metal sheet on the first central die structure, and the central die cutting surface cooperates with the first central die structure of the second die structure for stamping the metal sheet there after the metal sheet has been tensioned onto the first central die structure so as to provide the sheet Metallic the desired configuration.

According to another aspect of the present invention, a method is provided for the formation of exterior body panels for motor vehicles. The present invention provides a method comprising assembling a sheet in a die assembly, first holding the peripheral portion of the sheet of metallic material between the clamping surfaces of the die assembly, moving the clamping surfaces relative to a structure central die so that the metal sheet is deformed on the central die structure, holding the second peripheral portion of the metal sheet between a die stamp of the die assembly and the central die structure after the metal sheet is deformed on the central die structure, moving the clamping surfaces in relation to the central die structure to tension the metal sheet on the central die structure after the peripheral portion of the metal sheet has been engaged, and die cutting the sheet metallic material between the central structure and a punch opposite After the metal sheet has been tensioned on the die structure so as to provide the metal sheet with the desired configuration.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a metal sheet forming assembly showing an upper and lower die structure with a raw metal sheet to be formed therein according to the present invention; Figure 2 is a partial sectional view of a sheet metal forming assembly showing the upper die structure raised on the lower die structure and the metal sheet resting along the mobile peripheral portion of the lower die structure; Figure 3 is a view of the partial section similar to Figure 2, but showing the upper die structure in a lower position in which it secures three peripheral sides of the metal sheet; Figure 4 is a view of the partial section similar to Figure 3, but showing a movable step die assembly of the upper die structure securing the metal sheet in place along the fourth peripheral side; Figure 5 is a view of the partial section similar to Figure 4, but showing the upper die structure in a fully lowered configuration in which the metal foil is tensioned and punched in the desired configuration; Figure 6 is a view of the partial section taken orthogonally with respect to the sectional views of Figures 2-5, taken along line 6-6 in Figure 5, and showing the total length of the die assembly. tread of the upper die structure; Figure 7 is a perspective view of an exterior body panel forming the surface of the exterior side of a rear box for a pick-up truck that has been formed in accordance with the present invention; Y Figure 8 is a cross-sectional view taken along line 8-8 in Figure 7, and showing the position of this section in relation to the die-cut metal sheet.

DETAILED DESCRIPTION OF THE INVENTION With reference to Figure 1, a metal sheet forming die assembly 10 is illustrated, covering the principles of the present invention. The sheet metal forming die assembly 10 (known as a deep stamping assembly) includes first and second die assemblies. The first die assembly is a lower die assembly 14, and the second die assembly is an upper die assembly 12 which cooperates to form the sheet of metallic material 16 placed there. In the presently described aspect, the unprocessed metal sheet has essentially four sides, of a rectangular configuration. It can be appreciated, however, that the present invention is not limited to unprocessed metal sheets of such configuration. The upper die assembly 12 is mounted in a conventional hydraulic press (not shown) to allow the upward and downward movements of the upper die assembly 12.

The lower die assembly 14 includes a lower horizontal support member or die pedestal 22. The central fixed die structure has an upwardly facing die surface 26, in accordance with the desired shape of the metal sheet 16. A peripheral portion movable or holding structure 28 of the lower die assembly 14 surrounds the fixed central die structure 24 and is mounted on pneumatic spring elements 30 extending upwardly from the pedestal of the lower die 22. The spring elements 30 drive the structure peripheral engagement 28 in an upward direction. The movable peripheral engagement structure 28 has an upper surface -29, which is disposed slightly higher than the upper surface 26 of the structure 24 when the assembly is at rest (e.g., in Figures 1 and 2).

As shown in Figure 2, the hardened steel wear plates 32 provided at the interface between the peripheral movable clamping structure and the fixed central die structure 24 serve to provide a conventional guide and wear surface. The periphery of the metal sheet 16 is mounted on the upper surface 29 of the mobile peripheral clamping structure 28. More specifically, as can be seen from Figure 1, the upper surface 29 has three peripheral surface areas facing upwards 3-4 , 35 and 36 which are constructed and arranged to mate with the lower part of the metal sheet 16 with its three peripheral adjacent sides 31. A fourth peripheral surface area 37 extends beyond the adjacent edge of the metal sheet 16 when the metal sheet 16 is properly mounted in the assembly 10. Therefore, as can be seen from Figure 2, an edge 33 of the metal sheet is left suspended over the fixed central structure 24. The three peripheral edges 31 constitute a first peripheral portion of the metallic sheet 16, while the fourth peripheral edge 33 constitutes a second peripheral portion of the sheet Tile 16, in which a first and second portions of the metal sheet are formed differently in the die assembly 10, as will be described.

A slot 38 is formed in the above-mentioned areas 34, 35 and 36, and the movable peripheral clamping structure 28. The upper punch assembly 12 has a peripheral portion 44 and a central portion 48. The peripheral portion 44 has a surface of peripheral upward facing fastener 42 forming an assurance molding 40. The molding 40 is provided along the three surface areas of the upper peripheral clamping surface 42, which is constructed and arranged to couple the three surface areas 34, 35, and 36 of the movable peripheral clamping structure 28. The molding 40 is located directly on the slot 38 and has substantially the same shape. The molding 40 and the slot 38 are joined in a coupling-securing relationship, such that they secure therein a first peripheral portion of the metal sheet, including the three peripheral sides 31 of the metal sheet 16 as the die assembly descends. higher.

The central portion 48 of the upper die assembly 12 has an upper die face surface facing downwards 50 surrounded by a vertical peripheral surface 52.

The upper die surface 50 and the lower die surface 26 have a substantially inverted configuration with respect to each other whereby the upper die surface 50 cooperates with the lower die surface 26 to die and form there the central portion of the die. the sheet of metallic material 16 when the upper die assembly 12 descends (for example, see Figure 5).

The upper die assembly 12 consists of an upper die head structure 13 an independent movable upper die die assembly generally shown as 54. More specifically the step die assembly 54 is received in a box 55 in the central portion 48 of the upper die structure 13. The upper step die assembly 54 is attached to the upper die structure 13 by an upper mounting plate 56. As can best be seen in Figure 6, the cylindrical pneumatic elements, preferably nitrogen cylinders, 58 are directly attached to the upper mounting plate 56 and extend from that point vertically downwards. Each pneumatic cylinder 58 comprises an upper cylinder portion that telescopically receives a piston rod 62. The lower end of the piston rod 62 is attached to a pressure plate 64. A die-casting steel die 66 of the die assembly upper step 54 has a generally U-shaped cross section defining an interior space 69 in which the cylinders 58 are received. The U-shaped section is defined by the walls 68 and 70 and by the horizontal base 72. The plate The pressure 64 is internally connected to an internal surface 76 of the base 72 and forms the interconnection between the cylinders 58 and the stepped die element 66.

The parallel walls 68 and 70 of the movable tread die member 66 have wear plates 78 along their outer surfaces cooperating with the wear plates 80 along the surfaces defining the case 55 in the central portion of the base. upper die 48 for guiding and directing the mobile treading die 66.

The stepped movable member 66 includes a lower die surface 86 that includes a protruding beading molding 88. The securing molding 88 is positioned directly over the longitudinal slot 90 that is formed along the upper surface 26 of the latch structure. stationary die 24 in a position adjacent to the fourth surface area 37 of the movable peripheral clamping structure 28 of the lower die assembly. The slot 90 is located below a peripheral side portion of the metal sheet 16 adjacent the edge 33 and cooperates with the securing molding 88 to secure there the aforesaid peripheral position of the metal sheet 16 as will be described in more detail below.

As can be seen in Figure 3, when the upper punch assembly 12 moves downwardly under hydraulic force, the downward facing fastening surface 42 of the peripheral portion 44 of the upper punch assembly 12 engages the metal sheet 16 at length of three peripheral side portions adjacent to the three edges 31. The securing molding 40 cooperates with the slot 38 to trap and secure the metal sheet 16 along the three adjacent edge portions 31. Also as shown in the Figure 3, when the upper die assembly 12 continues to descend, the movable peripheral clamping structure 28 of the lower die assembly 14 descends by forcing the thrust of the pneumatic spring members 30. By continuing forced downward movement of the peripheral clamping structure 28, the lower side of the metal 16 eventually engages the upper surface 26 of the fixed central structure 24, and the movement Further descending of the upper die assembly 12 and the peripheral clamping structure causes the metal sheet 16 to be tensioned on the fixed central structure 24.

After a slight deformation of the metal sheet 16 on the fixed central structure 24 as shown in Figure 3, or perhaps even after a slight tensioning of the metal sheet 16 on the fixed central die structure 24 as shown in FIG. Figure 4, the stepped member 66 makes contact with and holds the fourth adjacent edge portion 33 of the metal sheet 16 with the top surface 26 of the fixed central die part 24 as shown in Figure 4. This assurance or engagement of the fourth peripheral portion of the metal sheet 16 is facilitated by the cooperation between the securing molding 88 and the slot 90. The movable treading die member 66 engages the adjacent peripheral portion 33 of the metal sheet 16 that is formed to a final portion of the die-cut product which is not provided with any significant structural depth, and in any case, a structural depth less than three other edge portions 31, and therefore does not need to be tensioned to any extent.

It will be appreciated by those skilled in the art that the arrangement of the securing molding 88 and the slot 90 and the securing molding 40 and the slot 38 operate in such a way that the tensioning of the central portion of the metal sheet 16 on the structure Die 24 is substantially limited to portions of the metal sheet within the four limiting lines defined by these beading moldings and grooves.

As shown in Figure 5, the continued descent of the upper die assembly 12 and the lower peripheral clamping structure 28 cause a continuous tensioning of the metal sheet 16 until the upper central die surface 50 and the vertical peripheral surface 52 are move downward by engaging with the upper surface of the metal sheet 16. In addition, the cylinders 58 compress with the bar 62 extending into the cylindrical portion 60 against its push outwardly to increase the gripping force applied by the stepped member 66. At the end of the tensioning operation, the die surfaces puncture the sheet metal 16 and provide a final shape for the sheet metal structure. The tensioning of the metal sheet during the drawing operation results in the tempering of the metallic material increasing its strength.

After the drawing and punching operations, the excess sheet metal is cut along dotted lines 98 and 100 in Figure 5.

The present invention provides a die assembly 10 for punching a pattern in the metal sheet 16 in a press to form an exterior body panel of a vehicle engine. The die assembly includes a first die assembly 14 including a first central die structure 24 constructed and arranged to engage a surface of the metal sheet during the die cutting operation. The first die assembly 14 further includes a peripheral clamping structure 28 which is movable with respect to the first die structure 24 and constructed and arranged to engage the first peripheral portion 31 of the metal sheet 16. The second die assembly 12 it includes a second die structure 13 having a central die surface 50 constructed and arranged to engage an opposite surface of the metal sheet 16 during the die cutting operation. The second die structure 13 includes a peripheral clamping surface 42 constructed and arranged to cooperate with the movable holding structure 28 to hold there the first peripheral portion 31 of the metal sheet. The second die assembly further includes a movable step die assembly 54 that is movable with respect to the second die structure 13. The moveable step die assembly 54 cooperates with the first die frame 24 to hold there the second portion. peripheral 33 of the metal sheet 16. The first and second die assemblies 14 and 12, respectively, are constructed and arranged to be mounted on a press, the second die structure 12 being movable by means of the press in such a way that its surface peripheral clamping 42 cooperates with the movable clamping structure 28 of the first die assembly 14 to clamp there the first peripheral portion 31 of the metal sheet 16. The mobile step die assembly 54 is movable relative to the second die structure 13 and in the direction of the first die structure 24 in such a way as to secure the second peripheral portion 33 of the metal sheet 16 between the stepped die assembly 54 and the first die structure 24 after the metal sheet is deformed onto the first central structure 24. The peripheral clamping surface 42 and the movable holding structure 28 are moved to tension the sheet metal on the first central punch structure 24. The central punching surface 50 cooperates with the first central punch structure 24 for punching the metal sheet after the metal sheet has been tensioned on the first central punch structure 24 in such a manner which provides the desired configuration to the metal sheet.

In Figure 6, the independent movable punch component 54 is shown with the stepper member 66 engaging the metal sheet along the adjacent peripheral portion 33. The upper punch assembly 12 has been moved to its lowest point, and the metal sheet 16 has been formed in its final form. The longitudinal extension of the movable member does not extend along the total length of the upper surface 26 of the central die structure 24. Instead, the ends of the metal foil 16 are hooked by the surface portions 52 of the assembly. upper die forming a transition between the central surface portion 50 and the peripheral surface portion 42 of the upper die assembly 12.

The tensioning and initial forming of the metal sheet 16 as shown in Figure 3 sometimes takes place before the movable member 66 engages and secures the metal sheet 16 to the adjacent peripheral portion of the edge 33. This latching order it is important for the purpose of preserving and maintaining the ornamental nature of the finished metal foil product that can be used as an exterior body panel of a class A motor vehicle. More specificity in accordance with the present invention, the die assembly is particularly constructed and arranged to minimize surface slip marks and scratches that may occur during the die cutting and tensioning process, and is also constructed and arranged to reduce, or prevent panel distortions that may be inappropriate for the final surface finish, including painting, of the requirements for type A exterior panels As can be seen from Figure 5, since the depth of the resulting formed structure is not required along the three adjacent peripheral edge portions of the metal sheet 31, and is not required along the fourth edge portion. adjacent peripheral 33, it is not necessary to carry out the tensioning of the metal sheet along the adjacent edge portion 33. Since the material is not tensioned in the adjacent side portion 33, a greater degree of tensioning can be achieved adjacent to the remaining three portions 31. Therefore, the same desired resultant part can be manufactured from less material compared to an arrangement in which the fourth adjacent edge portion 33 of negligible depth required is tensioned thereto. depth than the three remaining side portions and cropped as waste.

Figure 7 is a perspective view of an exterior body panel made in accordance with the present invention. The body panel is in the form of a rear side panel generally indicated as 108 for the rear box of a pick-up truck. After the metal sheet is stamped or drawn, it is cut out and shaped in its final configuration. For example, the wheel opening 110 and the opening 112 for a backlight are formed. The front end portion 108 is transformed into a flange 114 as can be seen from the cross-sectional view in Figure 8, taken along the line 8-8 in Figure 7. It can be seen from Figure 8 that the flange 114 is formed by folding the end portion 116 of the metal sheet after it has been cut along the line 98. After the end portion 116 has been bent into the desired configuration for the outer panel for the back box, the outer surface 118 of the flange 114 is tied with the portion of the rear surface of the cab of a pick-up truck. Then the metal sheet is painted in a conventional painting station, along with the rest of the vehicle.

Advantages and modifications can easily be presented to those skilled in the art. Therefore, the present invention is not limited to the specific details and aspects shown and described herein. Accordingly, various modifications to the aspects and details described may be made without departing from the principles, spirit, and scope of the present invention.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

Having described the invention as above, the content of the following is claimed as property.

Claims (13)

1. A die assembly for the punching of a metal sheet in a press for the formation of an exterior body panel for a motor vehicle, the die assembly characterized in that it comprises: a first die assembly including a first central die structure constructed and arranged to engage a surface of the metal sheet during the die cutting operation, the first die assembly further including a peripheral holding structure that is movable with respect to the first die structure and constructed and arranged to engage the first peripheral portion of the metal sheet; a second die assembly including a second die structure having a central die surface constructed and arranged to engage an opposite surface of the metal sheet during the die-cutting operation, the second die structure including a peripheral clamping surface constructed and arranged to cooperate with the movable holding structure to hold there the first peripheral portion of the metal sheet. said second die assembly further includes a step die assembly that is movable with respect to the second die structure, the step die assembly being movable in cooperation with the first die structure to hold there the second peripheral portion of the die. metal foil, said first and second die assemblies constructed and arranged to be mounted in a press, the second die assembly being moved by the press in such a way that its peripheral clamping surface cooperates with the movable holding structure of the first die assembly for clamping there the first peripheral portion of the metal sheet, said peripheral clamping surface and said mobile clamping structure being moved with the first portions of the metal sheet there clamped to deform the metal sheet on the first central die structure, said stepped die being movable relative to the second die structure and in the direction of the first die structure in such a manner as to hold the second portions of the metal sheet between the moveable step die assembly and the first die structure afterwards. that the metal sheet is deformed on the first central die structure, said peripheral clamping surface and said movable clamping structure being moved to tension the metal sheet on the first central die structure, said central punching surface cooperating with said first central die structure for stamping the metal sheet there after the metal sheet has been tensioned on the first die structure in such a way as to provide the metal sheet with the desired configuration.
2. A die assembly according to claim 1, characterized in that the step die assembly includes a step die and at least one spring member that mounts the step die for movement relative to the second die structure.
3. A die assembly according to claim 2, characterized in that the first die assembly further comprises a plurality of spring members that mount the movable holding structure for movement.
4. A die assembly according to claim 3, characterized in that the second die structure is constructed and arranged to be mounted on an upper tamper of a press and is lowered until its clamping surface engages the metal sheet and holds the sheet metal against the movable holding structure, and wherein the continued descent of the second die structure causes the movable holding structure to move down against the thrust of the plurality of spring members until the metal sheet is deformed on the first central die structure.
5. A die assembly according to claim 4, characterized in that the stepped die moves against a spring thrust of at least one spring member after the stepped die holds the metal sheet against the first die structure.
6. A die assembly according to claim 2, characterized in that the second die structure has a box and wherein at least one spring member and the step die are disposed in the box.
7. A die assembly according to claim 6, characterized in that the second die structure has a mounting plate inside the box, and wherein one end of the at least one spring member is fixed to the mounting plate, and wherein an opposite end of the at least one collar member is fixed to the tread die.
8. A method for forming an exterior body panel for a motor vehicle characterized in that it comprises: fastening a first peripheral portion of the metal sheet between the clamping surfaces of the die assembly, the movement of the clamping surfaces in relation to the central die structure so as to deform the metal sheet on the central die structure, fastening a second portion of the sheet of metallic material between a die stamp of the die assembly and the core die structure after the metal sheet deforms over the central die structure, the movement of the clamping surfaces in relation to the central die structure to tension the metal sheet on the central die structure after. that the second peripheral portion of the sheet of metallic material has been fastened, the stamping of the metal sheet between the central structure and an opposing die surface after the metal sheet has been tensioned on the die structure so as to provide the metal sheet with the desired configuration.
9. A method according to claim 8, characterized in that it comprises an additional painting of the metallic material subsequent to the die-cutting.
10. . A method according to claim 8, characterized in that the die assembly comprises a lower die assembly and an upper die assembly, and the clamping surfaces of the die assembly comprising lower clamping surfaces provided in a movable peripheral clamping structure. of the lower die assembly and upper fastening surfaces provided in the upper die assembly, the clamping of the first peripheral portion is accomplished by lowering the upper die assembly so that its upper clamping surfaces move towards the lower clamping surfaces to engage there the first peripheral portion of the sheet of metal material.
11. . A method according to claim 10, characterized in that the deformation of the metal sheet on the central die structure is carried out by moving the upper die assembly and the peripheral holding structure of the lower die assembly in relation to the structure of central die while the first peripheral portion of the metal sheet is clamped between the upper and lower clamping surfaces, so that one side of the metal sheet is deformed in a generally conformal engagement with the upper surface of the die structure central.
12. 12. A method according to claim 11, characterized in that the stepped die is connected to the upper die assembly, and the central die structure forms part of the lower die assembly, and because the second peripheral portion of the sheet is held in place. of metallic material between the treading die and the central die structure is realized by lowering the upper die assembly until the treading die cooperates with the central die structure to engage the sheet of metallic material there after the foil of metallic material is deformed in the generally conformal coupling with the upper surface of the upper die structure.
13. 13. A method according to claim 11, characterized in that the sheet of metallic material is slightly tensioned after it is deformed in the generally conformational engagement with the upper surface of the central die structure. . A method according to claim 12, characterized in that the opposite die surface descends with the upper die assembly while the sheet of metallic material is being tensioned on the central die, the upper die assembly continues to descend until the die surface decreases. Opposing die meets the sheet of metallic material for punching the sheet of metallic material between the upper surface of the upper die structure and the opposite die surface. . A method according to claim 8, characterized in that the gripping surfaces of the die assembly cooperate to form an insurance molding constructed and arranged to secure said metal sheet, and in that said die is stepped on and the central die structure cooperates to form a molding. insurer constructed and arranged to secure said metallic sheet, said securing molds engaging said metal sheet in positions defining limits in which said metallic sheet is tensioned. . A method according to claim 8, characterized in that after said die-cutting, said sheet of metallic material is removed from said die assembly, and in that the peripheral portions of said sheet of metallic material, including said positions defining said limits, are cut out from the central portions of said sheet of metallic material. . A method according to claim 16, characterized in that said peripheral portions of said metal sheet are cut, said metal sheet is bent in the desired configuration for an outer panel of a rear box of a pick-up truck. A method according to claim 17, characterized in that it additionally comprises painting the sheet of metallic material subsequent to said bending in the desired configuration of said outer panel.