Device and method for shaping sheared edges on stamped or fine-blanked parts having a burr

Abstract

A device and a method for shaping sheared edges on stamped or fine-blanked parts having a burr include at least one cutting stage and at least one forming stage. The forming stage includes a shaping punch which has a shaping region for smoothing the sheared edge of the outer or inner contour of the workpiece to the net shape and an embossing shoulder for mashing the burr of the outer or inner contour. The shaping punch is configured so that the shaping region initially bends the burr on the outer or inner contour away from the sheared edge, then seizes the sheared edge for widening, wherein the embossing shoulder of the shaping punch mashes the burr on the outer or inner contour when the widening on the workpiece has ended and flattens the embossing bead, created during mashing, during separating of the shaping punch from the workpiece.

Claims

1. Apparatus for shaping sheared edges on stamped or fine-blanked work pieces having at least one burr, comprising an upper part and a lower part, which form at least one cutting stage comprising a stamping or fine-blanking stage for cutting at least one of outer or inner contours of the workpiece, and at least one forming stage for mashing the at least one burr created during cutting, the forming stage comprising a fixed upper die part having an embossing bell and a lower die part movable in a stroke direction and having an embossing anvil, wherein the forming stage comprises a shaping punch, which has a shaping region for smoothing sheared edges of the inner contour to a final shape and an embossing shoulder for mashing the burr of the inner contour, the shaping punch being configured so that the shaping region initially bends the at least one burr on the inner contour away from the respective sheared edge, then engages the sheared edges and, by material displacement, widens the inner contour along the circumference thereof, and so that the embossing shoulder of the shaping punch mashes the respective burr on the inner contour when the widening on the workpiece has ended and, during separating of the shaping punch from the workpiece, flattens an embossing bead created during the mashing.

2. The apparatus according to claim 1, wherein the shaping punch is configured for the inner contour of the workpiece.

3. The apparatus according to claim 1, wherein the shaping region of the shaping punch is formed of a spherical segment-shaped thickening that is provided at a head end thereof and is oversized in a defined manner in relation the inner contour for radially widening the sheared edge of said inner contour.

4. The apparatus according to claim 1, wherein the embossing shoulder is provided on the shaping punch at such a height from the head end of the shaping punch that, during vertical movement of the workpiece, the shaping region of the shaping punch first slightly bends the burr located on the inner contour away from the corresponding sheared edge and then engages the sheared edge to effect widening at the sheared edge inwardly of the inner contour by material displacement.

5. The apparatus according to claim 1, wherein the shaping punch is fixed on an upper block of the upper part in a stationary manner.

6. The apparatus according to claim 1, wherein the embossing bell is provided with an embossing shoulder and an ejector that is configured to be movable in the stroke direction is provided in the embossing bell to vertically guide the Shaping punch.

7. The apparatus according to claim 6, wherein the ejector is vertically guided by the embossing bell and is operatively connected to an upper hydraulic unit via pressure pins and an upper embossing pressure plate for moving the ejector with respect to the shaping punch.

8. The apparatus according to claim 6, wherein an upper hydraulic unit, which is operatively connected to the ejector via an upper embossing pressure plate, is accommodated in an upper block, and the shaping punch is attached in a fixed position on an upper embossing pressure plate.

9. The apparatus according to claim 6, wherein the ejector is operatively connected to an upper hydraulic unit via pressure pins that are subject to additional spring force for detaching the finished workpiece.

10. The apparatus according to claim 1, wherein the embossing anvil is vertically guided by a spring-loaded holder and is disposed on a lower embossing pressure plate which is operatively connected to a lower hydraulic unit for moving the embossing anvil in the stroke direction and back.

11. The apparatus according to claim 10, wherein the holder for the embossing anvil is vertically guided in an embossing positioning plate held by a cavity frame and has an annular surface which forms a seat for the embossing bell when the upper die part and the lower die part are closed.

12. The apparatus according to claim 11, wherein the cavity frame is fixed on a lower block in a stationary manner.

13. The apparatus according to claim 10, wherein the lower hydraulic unit is accommodated in a lower block and is operatively connected to the embossing anvil by lower pressure pins via a lower embossing pressure plate that is additionally supported by spring force.

14. The apparatus according to claim 1, wherein the embossing bell is configured for fixing the outer contour of the workpiece and has an annular configuration and completely surrounds the outer contour of the workpiece.

15. The apparatus according to claim 1, wherein the shaping region is circumferentially formed at an end of the shaping punch and has an outer circumference which is less than any other miter circumference of the shaping punch.

16. The apparatus according to claim 1, wherein the shaping region is circumferentially formed at an end of the shaping punch and comprises an annular protrusion extending circumferentially around the shaping region.

17. The apparatus according to claim 1, wherein the embossing bell comprises an embossing shoulder on an inside surface, the embossing shoulder being defined by an inner circumferential notch formed on an inner end of the embossing bell.

18. The apparatus according to claim 1, wherein the shaping region is formed circumferentially at an end of the shaping punch, and wherein the embossing bell comprises a circumferential notch on an inside surface of an end thereof.

19. The apparatus according to claim 17, wherein the shaping region and the circumferential notch are spaced from one another and face one another along a plane defined by the shaping region and the circumferential notch.

20. A method for shaping sheared edges of stamped or fine-blanked workpieces having a burr, using an apparatus according to claim 1, comprising cutting the outer and/or inner contours from a flat strip comprising the workpiece within the upper part and the lower part of the apparatus in the stamping or fine-blanking stage, transferring the cut workpiece into the forming stage after the stamping or fine blanking has been completed, and then shaping the workpiece the forming stage by the following steps in a single operation; a) slightly bending the burr present on the sheared edge of the inner contour away from the sheared edge with the shaping punch having the shaping region, when the workpiece carries out a vertical movement in the stroke direction; b) widening the sheared edge of the inner contour of the workpiece with the shaping region of the shaping punch to the intended final shape and dimensions until the embossing shoulder on the shaping punch engages the burr on the sheared edge of the inner contour; c) creating an embossing bead in the sheared edge by mashing the burr of the inner contour of the workpiece with the embossing shoulder of the shaping punch; and d) flattening the embossing bead with the shaping region of the shaping punch during separating of the shaping punch from the workpiece by way of a vertical movement of the shaping punch counter to the stroke direction of the workpiece.

21. The method according to claim 20, wherein the widening according to step b) begins on the side of the sheared edge facing the burr and ends on the side of workpiece facing away from the burr.

22. The method according to claim 20, wherein shape and dimensions of the shaping punch are adapted to the inner contour of circular or non-circular openings the workpiece, with a dimension of the shaping punch being oversized by a predetermined amount.

23. The method according to claim 20, wherein the burr of the outer contour is mashed simultaneously with the burr of the inner contour by an embossing shoulder of the embossing bell, wherein the outer contour of the workpiece is fixed by the embossing bell, which is part of the upper die part, and the workpiece is deposited on the embossing anvil of the lower die part in an appropriately positioned manner.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings:

(2) FIGS. 1a and 1b show a perspective view and a section along line A-A of FIG. 1a of a fine-blanked workpiece for a commercially available centrifugal weight;

(3) FIG. 2 shows a perspective top view onto an exemplary arrangement of a fine blanking stage and a forming stage in a device according to the invention;

(4) FIG. 3a shows a schematic sectional illustration of the forming stage in the open state;

(5) FIG. 3b shows a schematic sectional illustration of the forming stage with a returned embossing anvil;

(6) FIG. 3c shows a schematic sectional illustration of the forming stage in the clamped state;

(7) FIG. 3d shows a schematic sectional illustration of the forming stage in the state after mashing of the burr;

(8) FIG. 3e shows a schematic sectional illustration of the forming stage with a workplace partially detached from the shaping punch;

(9) FIG. 3f shows a schematic sectional illustration of the forming stage during opening;

(10) FIG. 4 shows an enlarged illustration of the shaping punch comprising an embossing shoulder and a shaping region provided at the head;

(11) FIG. 5 shows a perspective view of the upper die part of the device according to the invention in a depiction of revolution;

(12) FIG. 6 shows an enlarged illustration of the embossing bell comprising the embossing shoulder;

(13) FIG. 7 shows a perspective view of the lower die part;

(14) FIG. 8 shows a perspective view of the embossing anvil with the holder; and

(15) FIGS. 9a to 9e show schematic illustrations of the sequence of the method according to the invention with simultaneous mashing of the burrs on the outer and inner contours.

DETAILED DESCRIPTION OF THE INVENTION

(16) FIGS. 1a and 1b show a workplace 1 for a bob, for example, which was produced by way of fine blanking. On the outer contour 2, it has sheared edges 3 having rollover 4 and a burr 5, wherein the burr 5 is located on the side 6 of the workplace 1 facing away from the rollover. The inner contour 7 is formed by the sheared edges 8, which are part of two ellipsoidal holes 9. The sheared edges 8 likewise have a corresponding burr 5.1. The workpiece 1 has a thickness D of 6 mm, for example, and is made of steel.

(17) The workplace 1 is to be produced in a device that comprises an upper part 10 and a lower part 11 andas shown in FIG. 2is composed of at least one fine blanking stage 12 and at least one forming stage 13.

(18) The upper block 14 (FIG. 3a) of the upper part 10 is fixed in a stationary manner on a machine table, which is not shown, and the lower block 15 of the lower part 11 is fixed on a ram of a press so as to be able to perform stroke movements, so that the workpiece 1 is fine-blanked from bottom to topwhich is to say in the direction of the upper partfrom a flat strip in the fine blanking stage 12, which corresponds to the known prior art and therefore need not be described in more detail.

(19) The burr 5 of the sheared edge 3 of the outer contour 2 projects perpendicularly downward, while the burr 5.1 of the sheared edge 8 of the inner contour 7 projects perpendicularly upward from the workplace 1 (see also FIG. 1b).

(20) After having been ejected from the fine blanking stage 12, the fine-blanked workpiece 1 is seized by a cross elide 16 and transported by the same into the forming stage 13, where the workpiece is deposited in an accurately positioned manner prior to the forming step (see also FIGS. 3a to 3f).

(21) FIGS. 3a to 3f show the basic design of the forming stage 13 in a variety of processing states. The forming stage 13 comprises an upper die part 17 and a lower die part 18.

(22) The upper die part 17 includes an annular embossing bell 19, an ejector 20, and shaping punch 21. The embossing bell 19 is fixed to an upper embossing block 22a in a stationary manner, the embossing block 22a in turn being fixed to the upper block 14.

(23) The ejector 20 is supported vertically on the inner wall of the embossing bell 19 and horizontally on the upper embossing pressure plate 22, such that the ejector 20 is able to carry out a vertical relative movement with respect to the embossing bell 19.

(24) The operative connection between the ejector 20 and the upper embossing pressure plate 22 is established by pressure pins 25 that are additionally subject to spring force.

(25) The shaping punch 21 is inserted into the ejector 20, the punch in turn being held on the upper embossing block 22a in a stationary manner.

(26) The embossing pressure plate 22 is accommodated in the upper embossing block 22a and is operatively connected to an upper additional hydraulic unit 23 and a pressure pin 24. The ejector 20 is vertically guided and supported on the outer wall of the embossing bell 19 on one side and on the shaping punch 21 on the other side.

(27) The lower die part 18 is formed by a cavity frame 26, a holder 27, and an embossing anvil 8. The cavity frame 26 is attached to the lower block 15. The embossing anvil 28 is seated on a lower embossing pressure plate 29, which in turn is operatively connected via a lower additional hydraulic unit 30. The operative connection between the embossing pressure plate 29 and the lower additional hydraulic unit 30 is ensured by lower pressure pins 32. In addition, the lower embossing pressure plate 29 is held with the lower black 15 via a pin 38 that is placed under spring action by a compression spring 44.

(28) The holder 27, which contains the embossing anvil 28, is held in a spring-loaded manner on an intermediate plate 42 by way of a compression spring 31 guided by a pin 43, so that the holder 27 is able to carry out a vertically directed relative movement with respect to the embossing anvil 28 and the embossing positioning plate 29.

(29) The holder 27 moreover has a support surface 46, which forms a seat for the embossing bell 19 when the upper die part 17 and the lower die part 18 are closed.

(30) FIG. 3b shows the state of the embossing stage 13 when the embossing anvil 28 has returned. For this purpose, the lower additional hydraulic unit 30 decreases the load on the lower pressure pin 32, so that the embossing anvil 28 travels back with respect to the holder 27 in the direction of TDC so far that the fine-blanked workpiece 1 is seated in the holder 127 in an appropriately positioned manner.

(31) FIG. 3c shows the workpiece 1 when clamped between the ejector 20 and the embossing anvil 28, which is the prerequisite for starting the shaping process by way of the shaping punch 21.

(32) FIG. 3d shows the state after the burr mashing has been completed.

(33) In FIG. 3e, the upper additional hydraulic unit 24 has moved the shaping punch 21 back in the direction of bottom dead center with respect to the workpiece 1 on which the burr has been mashed. The workpiece 1 on which the burr has been mashed is partially detached, but not yet ejected.

(34) FIG. 3f shows the state in which the forming stage is open, before the cross slide 16 is moved in so as to discharge the workpiece 1.

(35) As is shown in an enlarged illustration in FIG. 4, the shaping punch 21 is appropriately adapted to the inner contour 7 of the workpiece 1, which is to say it has an ellipsoidal shape like the hole 9. The head 33 of the shaping punch 21 is shaped as a spherical segment-shaped thickening 34, which has defined slightly oversized dimensions compared to the inner contour 7 (holes 9). This thickening 34 on the shaping punch 21 forms a shaping region 35. As soon as the workpiece 1 clamped between the ejector 20 and the embossing anvil 28 moves from the bottom to the top during the stroke, the shaping region 35 first presses the burr 5.1 on the inner contour outward in the direction of the burr 5 on the outer contour 2 and then engages the sheared edges 8 of the inner contour 7, so that the inner contour 7 is widened along the circumference thereof by a defined degree by material displacement into the workplace interior, and the desired shape and dimensions are imparted to the inner contour 7 (see also FIGS. 9a to 9f).

(36) The shaping punch 21 moreover has an embossing shoulder 36, which is provided at a height H such that this is spaced vertically from the head end 45 of the shaping punch 21, which is slightly greater than the thickness D of the workpiece 1.

(37) Once the sheared edge 8 has moved past the shaping region 35 during the stroke of the workpiece 1, the inner contour 7 (hole 9) is widened by a defined degree and smoothed. The embossing shoulder 36 of the shaping punch 21 has seized the burr 5.1 on the inner contour and mashed it into the upper face of the workpiece 1, whereby an embossing bead 47 is created on the sheared edge 8.

(38) FIGS. 5 and 6 show the design of the upper die part 17.

(39) The ejector 20, which is vertically guided on the inner wall 37 of the embossing bell 19 and acted upon by the pressure pins 25 so as to carry out a relative movement with respect to the fixed embossing bell 19, is inserted into the embossing bell 19 (see FIG. 5).

(40) The shape of the embossing bell 19 is adapted to the outer contour 2 of the workplace 1, whereby the circumference of the outer contour 2 can be completely surrounded by the inner wall 37 of the embossing bell 19.

(41) The shaping punches 21 are attached to the upper embossing pressure plate 22 by screw bolts 38a and vertically guided in the ejector 20, so that the shaping punches 21 are fixed on the upper embossing block 22a in a stationary manner.

(42) FIG. 6 shows a section of the embossing bell 19 along line B-B in FIG. 5. An embossing shoulder 39 is provided on the inner wall 37 of the embossing bell 19 along the circumference thereof. This embossing shoulder 39 is designed so as to be able to mash the upwardly projecting burr 5 on the outer contour 2 as soon as the workpiece 1 seizes the upwardly projecting burr 5.1 during the stroke movement. The embossing shoulder 39 is provided at a height h that corresponds to the height H of the shaping punches 21. This ensures that the mashing on the inner contour 7 and the outer contour 8 takes place simultaneously on the workpiece 1.

(43) The lower die part 18 is shown in FIG. 7 in a depiction of revolution. The lower die part is composed of the embossing anvil 28, a holder 27 for the embossing anvil 28, an embossing positioning plate 40, a shim 41, the lower embossing pressure plate 29, and an intermediate plate 42.

(44) FIG. 8 shows a section of the lower die part 18. It is clearly apparent that the holder 27 is held on the intermediate plate 42 by way of the compression spring 31 in conjunction with the screw bolt 43, and the intermediate plate 42 is held in a spring-loaded manner on the lower block 15 of the forming stage 13 by way of a compression spring 44 and a pin 43 (see also FIG. 3a).

(45) The sequence of the method according to the invention is shown based on FIGS. 9a to 9e.

(46) FIG. 9a is based on the open state of the device. The ejector 20 and the embossing anvil 28 are not shown in detail for the sake of simplicity. The shaping region 35 and the embossing shoulder 36 of the shaping punch 21, and the embossing shoulder 39 of the embossing bell 19 are located non-engaged above the workpiece 1.

(47) FIG. 9b shows the state in which the workpiece 1 has reached the burr 5.1 on the sheared edge 8 of the inner contour 7 during the stroke. The upwardly projecting burr 5.1 is bent slightly outward in the direction of the outer contour 2 with the burr embossing radius GR by the spherical segment-shaped thickening 34, so that the subsequent mashing of the burr 5.1 extends outwardly away from the inner contour 7.

(48) After another stroke of the workpiece 1, the spherical segment-shaped thickening 34 of the shaping region 35 seizes the sheared edge 8 of the inner contour 7 and displaces material into the interior of the workpiece 1. This creates a defined widening of the inner contour 7 on the workplace 1. The defined widening is determined by the oversized dimension of the shaping region 35 in relation to the inner contour 7 or the hole 9 (see FIG. 9c). The widening of the inner contour is ended as soon as the sheared edge 8 no longer engages the shaping region 35, which is to say as soon as the shaping region 35 of the shaping punch 21 has moved through the inner contour 7.

(49) FIG. 9d shows that the embossing shoulder 36 of the shaping punch 21 has mashed the slightly bent burr 5.1 on the workpiece 1 away from the inner contour 7. The embossing shoulder 39 of the embossing bell 19 engages the burr 5 of the sheared edge 3 of the outer contour 2 simultaneously with the embossing shoulder 36 of the shaping punch 21, so that the burr 5 is mashed on the workpiece 1 in the direction of the inner contour 7.

(50) If only one outer contour 2, such as a disk, is to be produced, the simultaneous mashing is dispensed with of course, without departing from the method according to the invention.

(51) FIG. 9e shows the state in which the shaping punch 21 carries out a return stroke movement counter to the stroke direction HR so as to demold the shaping punch 21 from the workpiece 1. The shaping region 35 seizes the embossing bead 47 during the return stroke and flattens the same to the final dimensions.