Drawing die for working depressions of a sheet-metal component, in particular of a motor vehicle

Abstract

The present invention relates to a drawing die (10) for working depressions(76) of a sheet-metal component (26), in particular of a motor vehicle, comprising a load-bearing structure (12), at least one supporting portion (16), which is fastened or can be fastened on the load-bearing structure (12) and with which the drawing die (10) can be placed on the sheet-metal component (26), characterized by a drawing means (28) which can be connected to the sheet-metal component (26) and is mounted on the load-bearing structure (12), and a moving device (36), which is mounted on the load-bearing structure (12) and by means of which the drawing means (28) can be moved in relation to the sheet-metal component (26), wherein at least the load-bearing structure (12) is formed from a fiber-reinforced plastic (52).

Claims

1. A drawing die (10) for working depressions (76) of a sheet-metal component (26), comprising: a load-bearing structure (12); at least one supporting portion (16) which is fastened or can be fastened on the load-bearing structure (12), and with which the drawing die (10) can be placed on the sheet-metal component (26); drawing means (28) that is connectable to the sheet-metal component (26) and mounted on the load-bearing structure (12); and a moving device (36) mounted on the load-bearing structure (12), by means of which moving device the drawing means (28) can be moved relative to the sheet-metal component (26), wherein at least the load-bearing structure (12) is made of a fiber-reinforced plastic (52), wherein the supporting portion (16) is formed from the fiber-reinforced plastic (52), wherein the fiber-reinforced plastic (52) is reinforced with organic or inorganic reinforcing fibers (54), and wherein a ratio of reinforcing fibers (54) to plastic in the fiber-reinforced plastic (52) is between 10% (w/w) and 30% (w/w).

2. The drawing die (10) according to claim 1, characterized in that the plastic (52) is reinforced with carbon fibers (56).

3. The drawing die (10) according to claim 1, characterized in that the ratio of reinforcing fibers (54) to plastic in the fiber-reinforced plastic (52) is between 13% (w/w) and 17% (w/w).

4. The drawing die (10) according to claim 3, characterized in that the plastic is a thermoplastic material.

5. The drawing die (10) according to claim 4, wherein the plastic comprises polyamide.

6. The drawing die (10) according to claim 1, characterized in that the load-bearing structure (12) and/or the supporting portion (16) and/or the moving device (36) has, at least in sections, a honeycomb structure (50).

7. The drawing die (10) according to claim 1, characterized in that the drawing means (28) comprises a threaded rod (30), which threaded rod can be screwed into a corresponding threaded bore (48) arranged on the moving device (36) or cooperating with the moving device (36).

8. The drawing die (10) according to claim 7, characterized in that the threaded bore (48) is arranged in a rotatable disc (46) which abuts against the moving device (36) or the load-bearing structure (12).

9. The drawing die (10) according to claim 1, characterized in that the moving device (36) comprises a lever arrangement (38) for moving the drawing means (28).

10. The drawing die (10) according to claim 1, characterized in that the load-bearing structure (12) comprises a cross member (14), wherein the one or plurality of supporting portions (16) is/are movably attachable to or secured along the cross member (14).

11. The drawing die (10) according to claim 10, characterized in that the plastic (52) of the cross member (14) is reinforced with organic or inorganic reinforcing fibers (54), wherein the reinforcing fibers are arranged directionally in the cross member (14).

12. The drawing die (10) according to claim 11, wherein the organic or inorganic reinforcing fibers (54) comprise carbon fibers.

13. The drawing die (10) according to claim 10, characterized in that the plastic (52) is a thermosetting plastic.

14. The drawing die (10) according to claim 13, wherein the thermosetting plastic comprises an epoxy resin.

15. The drawing die (10) according to claim 10, characterized in that the supporting portion (16) has a first subsection (18) that wraps around the cross member (14) and a second subsection (20), wherein the second subsection (20) is rotatably attached to the first subsection (18) at least about an axis of rotation (D) and comprises a support surface (25) for resting on the sheet-metal component (26).

16. The drawing die (10) according to claim 10, characterized in that the drawing means (28) and the moving device (36) are movably attached or attachable along the cross member (14).

17. The drawing die (10) according to claim 1, characterized in that the drawing means (28) has a hook-shaped connecting element (34) at one end, with which pull tabs (80), which are fastened or can be fastened to the sheet-metal component (26), can be connected to the drawing means (28).

18. The drawing die (10) according to claim 1, characterized in that the drawing die (10) has an electrically operated heating device (70) with which a mouthpiece (68) arranged at one end of the drawing means (28) can be heated in such a way that the mouthpiece (68) can be connected to the sheet-metal component (26) to form a welded joint (78).

19. The drawing die (10) according to claim 18, characterized in that the supporting portion (16) encloses at least one through hole (66) which can be penetrated by the drawing means (28).

20. The drawing die (10) according to claim 1, wherein the sheet-metal component (26) is a sheet-metal component of a motor vehicle.

Description

(1) Exemplary embodiments of the invention are explained in more detail below with reference to the accompanying drawings.

(2) Wherein

(3) FIG. 1 shows a first embodiment of a drawing die according to the invention,

(4) FIG. 2 shows a second example of a drawing die according to the invention,

(5) FIG. 3 shows a third embodiment of a drawing die according to the invention, in each case on the basis of a perspective view,

(6) FIG. 4 shows a principal partial representation of a drawing die according to a fourth embodiment, and

(7) FIG. 5 shows a principal partial representation of a drawing dies according to a fifth embodiment.

(8) In FIG. 1, a first embodiment of a drawing die 10.sub.1 according to the invention is shown by means of a perspective view. The drawing die 10.sub.1 comprises a load-bearing structure 12, which in the first embodiment comprises a cross member 14. Two supporting portions 16 are attached to the cross member 14, each supporting portion having a first subsection 18 and a second subsection 20. The first subsection 18 forms an aperture 22 through which the cross member 14 can pass. The supporting portion 16 can be moved along the cross member 14. The cross member 14 has two elongated slots 24, through each of which a set screw 17 can be passed, by means of which set screw the supporting portion 16 can be fixed in the desired position relative to the cross member 14. The second subsection 20 is rotatably attached to the first subsection 18 about an axis of rotation D and serves to support the drawing die 10.sub.1 on a sheet-metal component 26 (see FIG. 4 and FIG. 5), which will be discussed in more detail below. For this purpose, the second subsection 20 forms a support surface 25.

(9) Furthermore, the drawing die 10.sub.1 comprises a drawing means 28, which in the first embodiment shown is implemented as a threaded rod 30, which is passed through a guide bore 32 arranged in the cross member 14 and which can be moved along a longitudinal axis L in the guide bore 32. With reference to the embodiment selected in FIG. 1, a connecting element 34 is connected to the drawing means 28 at the lower end of the drawing means 28, which connecting element is hook-shaped in the first embodiment example shown. The exact function of the connecting element 34 will be described in more detail below.

(10) Furthermore, the drawing die 10.sub.1 according to the invention is equipped with a moving device 36, with which the drawing means 28 can be moved along its longitudinal axis L. The moving device 36 comprises a lever arrangement 38, in the present example with two main levers 40, which are on the one hand rotatably attached to the cross member 14 and on the other hand rotatably attached to a respective secondary lever 42. The secondary levers 42 are, in turn, rotatably connected to a force transmission element 44 belonging to the moving device, which moving device is traversed by the threaded rod 30. The force transmission element 44 interacts with a disc 46, which has a threaded bore 48 into which the threaded rod 30 is screwed. By rotating the disc 46 about the longitudinal axis L of the threaded rod 30, the disc 46 can be moved along the threaded rod 30. Since the thread of the threaded rod 30 and the thread of the corresponding threaded bore 48 are self-locking, the disc 46 can abut against the force transmission element 44 when it comes into contact therewith. The disc 46 therefore acts as a kind of movable stop by means of which the forces emanating from the lever arrangement 36 can be transmitted to the drawing means 28. The position of the drawing means 28 relative to the cross member 14 can hereby be varied. Alternatively, the threaded bore 48 may also be arranged in the force transmission element 44 (not shown), into which the threaded rod 30 is screwed. In this case, the disc 46 can be dispensed with.

(11) The drawing die 10.sub.1 is shown in FIG. 1, in a position in which the drawing means 28 has been moved to the maximum upward position. With reference to the illustration selected in FIG. 1, the two main levers 40 are in a vertical position. If the main levers 40 are each respectively rotated by 90 so that they are approximately parallel to the cross member 14 and consequently approximately horizontal, with reference to the representation selected in FIG. 1, the drawing means 28 is moved downward. The most important movement in operation of the drawing dies 10.sub.1 is to move the two main levers 40 from the approximately horizontal position back to the vertical position shown in FIG. 1, which moves the drawing means 28 upward with respect to the representation selected in FIG. 1.

(12) In the first embodiment shown in FIG. 1, the main levers 40, the secondary levers 42 and the supporting portions 16 each have a honeycomb structure 50. The size of the honeycombs may be different. The first subsection 18 of the supporting portion 16 has a honeycomb structure 50 in the area of the aperture, in which the honeycombs are smaller than in the remainder of the first subsection 18. The honeycombs of the honeycomb structure 50 of the secondary levers 42 are smaller than the honeycombs of the honeycomb structure 50 of the main levers 40.

(13) In addition, FIG. 1 shows a section of the cross member 14 in the inset, as viewed along the section plane A-A, such section is not to scale and is purely in principle. The section plane A-A runs perpendicular to the main load direction of the cross member 14, which runs approximately along the longitudinal axis L. It can be seen from this section A-A that the cross member 14 is made of a fiber-reinforced plastic 52. For this purpose, the plastic 52 has organic or inorganic reinforcing fibers 54, which, in particular, are implemented as carbon fibers 56. In so doing, the ratio by weight of reinforcing fibers 54 to plastic 52 is between 10% and 30%. The plastic in this case is a thermosetting plastic, for example, a polyester, a vinyl ester or epoxy resin. The carbon fibers 56 extend in the plane A-A or parallel thereto. When a load is exerted along the longitudinal axis L, the cross member 14 is subjected to bending, resulting in tensile forces in the cross member 14 which act approximately along the plane A-A or parallel thereto. Due to the orientation of the carbon fibers 56 in the cross member 14, these tensile forces can be well absorbed, so that the cross member 14 has high rigidity against bending.

(14) As can also be seen from section A-A, the carbon fibers 56 each extend crosswise at an angle of about 45 with respect to the longitudinal axis LQ of the cross member, so that the intersecting carbon fibers 56 form an angle of 90. In operation, the drawing die 10.sub.1 is placed with the support surface 25 on a sheet-metal component 26. In many cases, the surface of the sheet-metal component 26 is curved, so that the two supporting portions 16 are not exactly aligned with respect to the longitudinal axis LQ of the cross member, but rather are rotated with respect thereto. This introduces torsional moments into the cross member 14. As a result, tensile forces are generated in the cross member 14 which act at an angle of 45 to the longitudinal axis LQ of the cross member, which is to say exactly along the direction along which the carbon fibers 56 are also aligned. The carbon fibers 56 can therefore absorb these forces well, so that, in addition to the high bending rigidity already mentioned, a high torsional rigidity about the longitudinal axis LQ of the cross member is also achieved. Mats are used to align the carbon fibers 56. In this case, the carbon fibers 56 are formed as long fibers. The cross member 14 can be produced, for example, using the so-called wet pressing process or the prepreg manufacturing process.

(15) The supporting portions 16 and at least parts of the moving device 36 are also made of a fiber-reinforced plastic 52. In this case, too, the ratio by weight of reinforcing fibers 54 to plastic 52 is between 10% and 30%. In this case, the supporting portions 16 and the moving device 36 are made of a thermoplastic, for example, polyamide 6.6. The reinforcing fibers 54 can also be implemented as carbon fibers 56, but in this case as short fibers, so that the supporting portions 16 and the moving device 36 can be manufactured by injection molding.

(16) In FIG. 2, a second embodiment example of the drawing die 10.sub.2 according to the invention is also shown by means of a perspective view. The basic construction of the drawing die 10.sub.2 according to the second embodiment largely corresponds to the construction of the drawing die 10.sub.1 according to the first embodiment, which is why the main differences will be discussed below. Compared to the cross member 14 of the drawing die 10.sub.1 according to the first embodiment example, the cross member 14 of the drawing die 10.sub.2 according to the second embodiment example is significantly longer. In addition, the drawing means 28 and the moving device 36 are movable along the cross member 14, for which purpose a set screw 58 is provided, by means of which the position of the drawing means 28 and the moving device 36 can be fixed with respect to the cross member 14 once they have been brought into the desired position.

(17) As in the first embodiment, the two supporting portions 16 are also movably mounted along the cross member 14.

(18) The supporting portions 16 of the drawing die 10.sub.2 according to the second embodiment example have two second subsections 20.sub.1, 20.sub.2, each of which is independently rotatably mounted about an axis of rotation D on the first subsection 18.

(19) In the second embodiment example, the load-bearing structure 12, the supporting portions 16 and the moving device 36 are likewise made of a fiber-reinforced plastic 52. In the second embodiment example, the main levers 40 and the supporting portions 16 each also have a honeycomb structure 50. In addition, the force transmission element 44 also has a honeycomb structure 50.

(20) FIG. 3 shows a third embodiment of the drawing die 10.sub.3 according to the invention. In this embodiment, the lever arrangement 38 has a slightly different configuration than in the first and second embodiments of the drawing die 10.sub.1, 10.sub.2 according to the invention. The first main lever 40.sub.1 of the lever arrangement 38 is fixedly attached to the cross member 14. The second main lever 40.sub.2 is connected to the first main lever 40.sub.1 via an intermediate lever 60. The intermediate lever 60 is rotatably connected to the first main lever 40.sub.1 and rotatably connected to the second main lever 40.sub.2. The second main lever 40.sub.2, in turn, is rotatably connected to the drawing means 28 by means of a connecting screw 62. Consequently, the drawing means 28 follows the movement of the second main lever 40.sub.2 relative to the first main lever 40.sub.1. Furthermore, a handle element 64 is connected to the drawing means 28. A user can apply a force to the drawing means 28 via the handle element 64.

(21) In this case, the second subsection 20 of the supporting portion 16 forms a through hole 66 which can be penetrated by the drawing means 28. With respect to the representation selected in FIG. 3, the drawing means 28 is connected to a mouthpiece 68 at the bottom end. The mouthpiece 68 can be heated by a heating device 70 which is not visible in FIG. 3.

(22) The first main lever 40.sub.1, the second main lever 40.sub.2, the intermediate lever 60, the handle element 64 and the cross member 14 each have a honeycomb structure 50 and are made of or comprise a fiber-reinforced plastic 52.

(23) A fourth embodiment example is shown in FIG. 4 by means of a principal partial representation. The fourth embodiment of the drawing die 10.sub.4 according to the invention is largely similar to the third embodiment. FIG. 4 is intended, in particular, to illustrate the heating device 70, which is not visible in FIG. 3, and its mode of operation. The heating device 70 may be connected to an external power source 72 so that electrical power may be supplied to the heating device 70. In addition, the heating device 70 is connected to wires 74 which are passed through the drawing means 28 and lead to the mouthpiece 68. In so doing, the wires 74 are configured to heat substantially only the mouthpiece 68.

(24) The essential operation of the drawing die 10.sub.3, 10.sub.4 according to the third and fourth embodiments can be seen from FIG. 4. The drawing die 10.sub.4 is placed with the second subsections 20 of the supporting portion 16 on a sheet-metal component 26, which has a depression 76 that is to be worked and in particular eliminated. The sheet-metal component 26 may, in particular, be a part of the outer skin of the body of a vehicle, for example, the hood or the side door. The drawing means 28 is brought into a position in which the mouthpiece 68 comes into contact with the sheet-metal component 26. This position can be established, for example, by moving the aforementioned disc 46 to a position such that it rests against the force transmission element 44 in the position shown (see, in particular, FIG. 1 and FIG. 2). Subsequently, the heating device 70 is activated so that the mouthpiece 68 is heated in the area in which it comes into contact with the sheet-metal component 26. In the process, the mouthpiece 68 is heated to such an extent that a welded joint 78 is formed between the mouthpiece 68 and the sheet-metal component 26. The heating device 70 is then deactivated, allowing the weld joint 78 to cool and solidify. Thereafter, a force directed substantially perpendicular to the sheet-metal component 26 and along the longitudinal axis L of the drawing means 28 is applied to the drawing means 28, in particular using the lever arrangement 38. In the embodiments shown in FIG. 1 and FIG. 2, the two main levers 40 are moved from a substantially horizontal position to a substantially vertical position, which are respectively shown in FIG. 1 and FIG. 2.

(25) In the third embodiment of the drawing dies 10.sub.3 shown in FIG. 3, the second main lever 40.sub.2 is moved towards the fixed first main lever 40.sub.1. Alternatively, the handle element 64 can also be pulled. In so doing, the sheet-metal component 26 follows the movement of the drawing means 28 in the region of the depression 76. The drawing means 28 is moved until the mouthpiece 68 is approximately aligned with the rest of the sheet-metal component 26 in the region in which it comes into contact with the sheet-metal component 26. In this manner, it is possible to eliminate the depression 76 so that the worked sheet-metal component 26 no longer has a depression 76 or at least no visible depression 76.

(26) The welded joint 78 can transmit comparatively high tensile forces, but it fails quickly when subjected to bending or torsion. In order to be able to separate once again the mouthpiece 68 from the sheet-metal component 26 after working the piece, the drawing die 10.sub.4 can be rotated or tilted, which breaks the welded joint 78.

(27) A fifth embodiment example of the drawing die 10.sub.5 according to the invention is shown in FIG. 5, here too on the basis of a principle partial illustration. The fifth embodiment corresponds essentially to the first and second embodiments of the drawing dies 10.sub.1, 10.sub.2. FIG. 5 serves, in particular, to explain the function of the connecting element 34. It should be noted that the drawing die 10.sub.1, 10.sub.2 according to the first and second embodiment examples does not have a heating device 70. For this reason, the drawing means 28 also cannot be connected to the sheet-metal component 26 through formation of a welded joint 78. Instead of a welded joint, a number of pull tabs 80 are connected to the sheet-metal component 26 forming a spot welded joint 78 in the area of the depression 76.

(28) Depending on the size of the depression 76, it may be sufficient to connect only one pull tab 80 in the depression 76 to the sheet-metal component 26, although the use of multiple pull tabs 80 is, in particular, recommended for larger depressions 76.

(29) Once the pull tabs 80 are connected to the sheet-metal component 26, the drawing die 10.sub.1 is positioned so that the hook-shaped connecting element 34 can positively engage the pull tab 80. Subsequently, as noted with reference to FIG. 4, the drawing means 28 is moved away from the sheet-metal component 26 along its longitudinal axis L using the lever arrangement 38 until the welded joint 78 is approximately aligned with the remainder of the sheet-metal component 26 outside the depression 76. When the working of the sheet-metal component 26 is finished, the engagement between the connecting element 34 and the pull tab 80 is released and the drawing die 10.sub.5 is removed. The welded joint 78 between the pull tab 80 and the sheet-metal component 26 may be broken by twisting and/or bending so that the pull tab 80 may be separated from the sheet-metal component 26.

LIST OF REFERENCES

(30) 10 Drawing die 10.sub.1 to 10.sub.5 Drawing die 12 Load-bearing structure 14 Cross member 16 Supporting portion 17 Set screw 18 First subsection 20 Second subsection 20.sub.1, 20.sub.2 Second subsection 22 Aperture 24 Elongated slot 25 Support surface 26 Sheet-metal component 28 Drawing means 30 Threaded rod 32 Guide bore 34 Connecting element 36 Moving device 38 Lever arrangement 40 Main lever 40.sub.1, 40.sub.2 Main lever 42 Secondary lever 44 Force transmission element 46 Disc 48 Threaded bore 50 Honeycomb structure 52 Fiber-reinforced plastic 54 Reinforcing fibers 56 Carbon fiber 58 Set screw 60 Intermediate lever 62 Connecting screw 64 Handle element 66 Through hole 68 Mouthpiece 70 Heating device 72 Power source 74 Wire 76 Depression 78 Welded joint 80 Pull tabs D Axis of rotation L Longitudinal axis LQ Cross member-Cross member Angle reinforcing fibers