Stamping die, method for manufacturing joint part of composite part by means of stamping die, and composite part

Abstract

The invention relates to a punching tool for punching stacked workpieces to form a joint point, characterized in that the punching tool has a punch system with a punch, and a die system with a cavity, the punch having at least two punch parts, the punch portions can be moved into or out of the cavity in a first direction, and the punch portions can be moved in a second direction transverse to the first direction between an open state further away from each other and a closed state closer to each other, in which the punch portions can be moved into the cavity, and in which the punch portions can be moved out of the cavity in a second direction transverse to the first direction. The punch portions are movable in the cavity from a closed state away from each other into an open state, in which the punch portions, on a section thereof capable of entering the cavity, have a protrusion protruding over an outer circumferential surface of the section in a second direction. The invention also relates to a method for producing a joint point of a composite part by means of a stamping tool and to a composite part.

Description

Technical Field

[0001] The invention relates to a punching die, a method for manufacturing a joint part of a composite part by using the punching die, and a composite part. Background Art

[0002] Traditional TOX rivetless connection is usually used to connect two stacked plates 4', such as metal plates. Its advantages are 1) environmental protection: no welding; 2) low cost: multiple points can be riveted at the same time, fast cycle, and low manufacturing cost. However, traditional TOX rivetless connection also has its disadvantages: 1) Mechanical properties: cannot reach the level of spot welding.

[0003] Fig.16 The schematic diagram shows a stamping die 1' for connecting two stacked plates 4' by a conventional TOX rivetless connection method, wherein the stamping die 1' comprises a cooperating punch 2' and a die 3', wherein the punch 2' has an integral punch 14', and the die 3' has a cavity 44' for receiving the material of the plate 4', and the cavity 44' has a vertical peripheral wall, i.e. parallel to the stamping direction of the punch 2'. The vertical peripheral wall facilitates the demoulding of the material after the stamping is completed.

[0004] Fig.17 The structure of the composite part 100' formed by two plate parts 4' at the stamped part, i.e., the joint part 101' is shown. It can be seen here that the lower plate part 4' has an undercut 102' on its inner side wall, and the material of the upper plate part 4' radially protruding due to the extrusion is accommodated in the undercut 102', so that the upper and lower plate parts 4' are perpendicular to the depth value t of the undercut 102'. U The shape-locking connection in the direction D' of the groove 105', that is, in the depth direction of the groove 105'. The depth value (locking value) of the undercut 102' is t U ', t formed by TOX riveting U The value is the guarantee of the pulling and shearing force. The traditional TOX riveting process forms t through the punch 14' vertical downward punching or axial punching process, which is the only freedom of movement. U ', it is formed by lateral extrusion, so the shape of the joint and t U ' value cannot be formed stably and the value is limited. Corresponding to the vertical side wall of the cavity 44' of the die 3', the outer side wall 104' of the lower plate 4' at the joint 101' also extends vertically to facilitate demoulding from the die 3' after stamping. In addition, the inner side wall 103' of the upper plate 4' at the joint 101' also extends vertically.

[0005] With more reliable rivetless connection joint part 101 '(larger and controllable t UThe composite part 100' with a high value of ' is urgently needed as a product. A stamping die 1' and a stamping method that can produce such a more reliable joint part 101' by rivetless stamping are also to be developed. Summary of the invention

[0006] The object of the present invention is to provide a stamping die, a method for manufacturing a joint portion of a composite part using the stamping die, and a composite part, which can solve at least one of the above-mentioned problems.

[0007] In order to achieve the above-mentioned purpose, the present invention proposes a stamping die, which is used to stamp stacked workpieces to form a joint portion, and is characterized in that the stamping die has a punch system and a die system, the punch system has a punch, and the die system has a cavity, wherein the punch has at least two punch parts, the punch parts can move into the cavity or move away from the cavity along a first direction, and the punch parts can move between an open state farther away from each other and a closed state closer to each other along a second direction transverse to the first direction, wherein the punch parts can move into the cavity in the closed state, and can move from the closed state away from each other to the open state in the cavity, wherein at least one of the punch parts has a protrusion on the section where it can enter the cavity that protrudes from the outer peripheral surface of the section in the second direction.

[0008] Here, for example, the first direction may be the axial direction of the punch or the punch part, and the second direction may be the transverse, radial or lateral direction of the punch or the punch part. In addition to the punching in the first direction, the multiple punch parts of the split punch can also move away from each other in the second direction in the cavity of the die system, thereby driving the protrusions on the punch parts to squeeze the materials of each workpiece in the second direction, so that each workpiece can have an undercut on the inner side wall at the joint portion, and the undercut can have a larger and controllable t U value, making the connection of the workpiece at the joint more secure.

[0009] Advantageously, the punch system has a push rod, and the punch part together encloses a cavity extending in the first direction, the push rod can be at least partially accommodated in the cavity, and the push rod can be moved between a first relative position and a second relative position relative to the punch part in the first direction, in the first relative position, the punch part is in the closed state, and in the second relative position, the punch part is in the open state.

[0010] Advantageously, the push rod has at least one push rod slope on its circumferential surface inclined to the first direction, and the punch part has a cavity slope on its inner wall defining the cavity, which cooperates with the push rod slope. In a first relative position of the push rod relative to the punch part, the push rod slope of the push rod and the cavity slope of the punch part abut against each other, and in the process of the push rod entering a second relative position from the first relative position relative to the punch part, based on the squeezing of the push rod slope of the push rod on the cavity slope of the punch part, the punch part enters the open state from the closed state.

[0011] Advantageously, the ejector pin slope and the cavity slope have a tapering radial dimension in a direction toward the die system.

[0012] Advantageously, two pairs of the push rod inclined surfaces and the cavity inclined surfaces are arranged at intervals in the first direction.

[0013] Advantageously, in a first relative position of the push pin relative to the punch portion, a bottom surface of the push pin facing the die system is further away from the die system than a bottom surface of the punch portion facing the die system, and in a second relative position of the push pin relative to the punch portion, the bottom surface of the push pin facing the die system is flush with the bottom surface of the punch portion facing the die system.

[0014] Advantageously, the punch system has a fixed plate, the punch part is at least partially accommodated in a punch accommodating portion of the fixed plate, the punch part has one of a protrusion and a recess extending in the second direction on the outer periphery, and the fixed plate correspondingly has the other of the protrusion and the recess in the punch accommodating portion, and the punch part is allowed to move between the closed state and the open state by guiding the protrusion in the recess, wherein, in the closed state of the punch part, there is a lateral gap between the punch part and the fixed plate.

[0015] Advantageously, the punch system has a stop plate, the punch part is at least partially accommodated in the punch accommodating portion of the stop plate, the punch parts have punch bevels inclined to the first direction on their outer circumferences, and the stop plate has a punch accommodating portion bevel inclined to the first direction on its inner wall defining the punch accommodating portion and cooperating with the punch bevel, wherein, in the open state of the punch part, the punch bevel and the punch accommodating portion bevel abut against each other, wherein, by squeezing the punch bevel of the punch accommodating portion bevel of the stop plate against the punch bevel of the punch part, the punch part can enter the closed state from the open state.

[0016] Advantageously, the punch receiving portion bevel and the punch bevel have a radial dimension which tapers in a direction away from the die system.

[0017] Advantageously, the die system comprises a die having at least two die parts, at least one of the die parts having a side recess, the die parts having a closed state closer to each other and an open state further away from each other, wherein in the closed state of the die parts, the die parts surround the cavity and the side recesses of the die parts constitute the side recesses of the cavity.

[0018] Advantageously, the die portion has a stepped surface, the stepped surface comprising a bottom surface and a side surface having the undercut.

[0019] Advantageously, the die system has a die core, which, in the closed state of the die parts, the die parts surround and, together with the die core, delimit the mould cavity.

[0020] Advantageously, the die portion has a step surface, which includes a bottom surface and a side surface having the undercut, wherein the bottom surface of the step surface and the top surface of the die core constitute the bottom surface of the cavity, and the side surface of the step surface constitutes the side surface of the cavity.

[0021] Advantageously, the die system comprises a die seat for supporting the die, and the die core is fixedly arranged on the die seat.

[0022] Advantageously, springs are provided between the die core and the die parts, respectively, and the die parts can be moved away from each other from a closed state to an open state under the effect of the resilience of the springs.

[0023] Advantageously, the die system comprises a one-piece die, the die having the cavity, the cavity having a bottom surface and side surfaces, the side surfaces having no undercut.

[0024] In order to achieve the above object, the present invention further provides a method for manufacturing a joint portion of a composite part using the stamping die according to the present invention, wherein the composite part has at least two superimposed workpieces, characterized in that the method comprises at least the following steps:

[0025] Placing step: placing at least two superimposed workpieces at their superimposed positions above the cavity of the die system,

[0026] The first punching step is to move the punch portion of the punch in a closed state along a first direction into the die cavity so that the material of the workpiece is squeezed into the die cavity along the first direction.

[0027] Second punching step: moving the punch parts away from each other in the cavity from a closed state into an open state so that the protrusions on the punch press the material of the workpiece in a second direction transverse to the first direction, thereby producing a joint portion of the composite part.

[0028] Advantageously, the method further comprises the steps of:

[0029] A first demoulding step: moving the punch parts closer to each other in the mold cavity from an open state to a closed state,

[0030] The second demolding step is to move the punch portion in a closed state along a first direction away from the cavity.

[0031] Advantageously, in the second punching step, the punch part is pressed from the closed state into the open state by relative movement of the ejector pin with respect to the punch part in the first direction.

[0032] Advantageously, in the first demoulding step, the punch part is pressed from the open state into the closed state by relative movement of the punch part with respect to the stop plate in the first direction.

[0033] Advantageously, the method further comprises a third demoulding step of moving the female mould parts of the female mould away from each other into an open state.

[0034] In order to achieve the above-mentioned purpose, the present invention proposes a composite part, which includes at least two superimposed workpieces, and is characterized in that the composite part has at least one joint part at the overlapping part of the workpieces, which is made using a stamping die according to the present invention or using a method according to the present invention, and the joint part has an inner wall and an outer wall, and the inner wall has a side recess formed by a protrusion on the punch.

[0035] Advantageously, the outer side wall projects laterally outwards at the undercut.

[0036] Advantageously, the lateral outward projection of the outer side wall at the undercut is formed by an undercut of the cavity of the matrix system.

[0037] Advantageously, the lower end width of the joint portion is greater than the upper end width thereof due to the lateral outward protrusion of the outer side wall. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The present invention will be explained in more detail below with the aid of embodiments with reference to the accompanying drawings, but the present invention is not limited to the embodiments described in the drawings and described in detail below. The accompanying drawings are as follows:

[0039] Figure 1 A cross-sectional view schematically shows a stamping die according to a first embodiment of the present invention;

[0040] Figure 2a Schematically showing the use of Figure 1 The stamping die in the stamping process is carried out in step 1;

[0041] Figure 2b Schematically shown Figure 2a The two stacked plates in step 1;

[0042] Figure 3a Schematically showing the use of Figure 1 Step 2 of the stamping process is performed by the stamping die in the stamping process;

[0043] Figure 3b Schematically shown Figure 3a The joint part of the plate in step 2;

[0044] Figure 4 Schematically shown Figure 2a Another partial view of the stamping die in FIG.

[0045] Figure 5a Schematically showing the use of Figure 1 Step 3 of the stamping process is performed by the stamping die in the stamping process;

[0046] Figure 5b Schematically shown Figure 5a The joint part of the plate in step 3;

[0047] Figure 6a Schematically showing the use of Figure 1 Step 4 of the stamping process is performed by the stamping die in the stamping process;

[0048] Figure 6b Schematically shown Figure 6a The joint part of the plate in step 4;

[0049] Figure 7 Schematically shown Figure 5a Another partial view of the stamping die in FIG.

[0050] Figure 8a Schematically showing the use of Figure 1 Step 5 of the stamping process of the stamping die;

[0051] Figure 8b Schematically shown Figure 8a The joint part of the plate in step 5;

[0052] Figure 9a Schematically showing the use of Figure 1 Step 6 of the stamping process of the stamping die;

[0053] Figure 9b Schematically shown Figure 9aThe joint part of the plate in step 6;

[0054] Fig.10 Schematically showing the use of Figure 1 The joint part of the composite part made by the stamping die;

[0055] Fig.11 A partial cross-sectional view of a stamping die according to a second embodiment of the present invention and one step of stamping a plate member using the stamping die are schematically shown;

[0056] Fig.12 Schematically showing the use of Fig.11 Another step of stamping the sheet metal part with the stamping die;

[0057] Fig.13 Schematically showing the use of Fig.11 The joint part of the composite part made by the stamping die;

[0058] Fig.14a An application example of manufacturing a composite part by a stamping die of the present invention is schematically shown;

[0059] Fig.14b Schematically shown Fig.14a A partial cross-sectional view of the composite part at the cutting line AA;

[0060] Fig.15a Another application embodiment of the stamping die manufacturing composite part of the present invention is schematically shown;

[0061] Fig.15b Schematically shown Fig.15a A partial enlarged view of the composite part;

[0062] Fig.15c Schematically shown Fig.15b A partial cross-sectional view of the composite part at the cutting line BB;

[0063] Fig.16 Schematically illustrates an existing stamping die; and

[0064] Fig.17 Schematically showing the use of Fig.16 The joint part of the composite part made by the existing stamping die. DETAILED DESCRIPTION

[0065] Illustrative embodiments of the present invention are described below. In this specification, for the sake of explanation only, various systems, structures and devices are schematically depicted in the accompanying drawings, but all features of the actual systems, structures and devices are not described, such as well-known functions or structures are not described in detail, so as to avoid unnecessary details that make the present invention unclear. Of course, it should be understood that in any practical application, many specific implementation decisions need to be made to achieve the specific goals of the developer or user, and system-related and industry-related restrictions need to be followed, and these specific goals may vary from practical application to practical application. In addition, it should be understood that such specific implementation decisions are complex and time-consuming, but this is a routine task for those of ordinary skill in the art who benefit from the present invention.

[0066] The terms and phrases used herein should be understood and interpreted as having a meaning consistent with the understanding of such terms and phrases by those skilled in the relevant art. Consistent usage of a term or phrase herein is not intended to imply a special definition of the term or phrase, i.e., a definition that is different from the ordinary and customary meaning as understood by those skilled in the art. For terms or phrases that are intended to have a special meaning, i.e., a meaning that is different from that understood by those skilled in the art, such special definition will be explicitly listed in the specification as a definition, directly and unambiguously giving the special definition of the term or phrase.

[0067] Unless required by the context, throughout the following specification, the word "include" and variations such as "comprising" and "having" are to be interpreted in an open, inclusive sense, that is, such as "including but not limited to".

[0068] Figure 1 The first embodiment of the punching die 1 of the present invention is schematically shown, which may include an upper punch system 2 and a lower die system 3, which cooperate to perform a punching process on two or more stacked panels 4 to obtain a more stable punching joint portion 101 of the present invention on the panels 4, thereby achieving a more reliable rivet-free connection of the panels 4. Figure 1 In the figure, the stacked plate 4 has been fixed on the stamping die 1, and the punch system 2 is in an initial state before the stamping process is performed on the plate 4. It can be imagined that in addition to the plate-shaped plate 4, other shapes of two workpieces with a planar stacking portion can be connected without rivets using the stamping die 1 of the present invention.

[0069] See also Figure 1, the male die system 2 may have a cylindrical ejector pin 5, and the ejector pin 5 may have four ejector pin sections 6, 7, 8, and 9 in a row, as viewed in a direction away from the female die system 3. The diameter of the second ejector pin section 7 may be greater than the diameter of the first ejector pin section 6, so that the two may form a first ejector pin slope 10 at the adjoining position, and the diameter of the first ejector pin slope 10 gradually decreases toward the female die system 3 (i.e., in a direction toward or close to the female die system 3); the diameter of the fourth ejector pin section 9 may be greater than the diameter of the third ejector pin section 8, so that the two may form a second ejector pin slope 11 at the adjoining position, and the diameter of the second ejector pin slope 11 gradually decreases toward the female die system 3. In addition, the diameter of the first ejector pin section 6 may be equal to the diameter of the third ejector pin section 8, and the diameter of the second ejector pin section 7 may be equal to the diameter of the fourth ejector pin section 9.

[0070] The ejector pin 5 may be connected to an ejector plate 12 and an ejector plate fixing plate 13 at its free end away from the die system 3. The ejector plate 12 and the ejector plate fixing plate 13 are fixed to each other (or optionally formed in one piece), and the ejector plate fixing plate 13 is provided with a receiving portion, here a through hole, for fixedly receiving the upper free end of the ejector pin 5. During the punching process, a downward pressure, i.e., toward the die system 3, or a punch ejector force, may be applied to the ejector pin 5 through the ejector plate 12. Similarly, a reverse force may be applied to move the ejector pin 5 upward, i.e., away from the die system 3.

[0071] The punch system 2 can have a split punch 14, which can include two punch parts 15 separated from each other and opposite to each other, and the two punch parts 15 can enclose a cylindrical cavity, which extends in the extension direction of the push rod 5 and can be geometrically adapted to the push rod 5. In some embodiments, the punch 14 can include more than two punch parts separated from each other and opposite to each other, which can enclose the above-mentioned cavity. The push rod 5 can be partially accommodated in the cavity and can move therein during the stamping process. Here, viewed in the direction away from the die system 3, the cavity of the punch 14 can have five cavity sections 16, 17, 18, 19, 20 in succession. Figure 1In the closed state of the punch 14 shown, the diameter of the first cavity segment 16 can be smaller than the diameter of the second cavity segment 17. The diameter of the second cavity segment 17 can be smaller than the diameter of the third cavity segment 18, so that the two can form a first cavity slope 21 at the adjoining position, and the diameter of the first cavity slope 21 gradually decreases toward the die system 3. The diameter of the fourth cavity segment 19 can be smaller than the diameter of the fifth cavity segment 20, so that the two can form a second cavity slope 22 at the adjoining position, and the diameter of the second cavity slope 22 gradually decreases toward the die system 3. In addition, the inner diameter of the second cavity segment 17 can be equal to the diameter of the first ejector pin segment 6, the inner diameter of the third cavity segment 18 can be equal to the diameter of the second ejector pin segment 7, the inner diameter of the fourth cavity segment 19 can be equal to the diameter of the third ejector pin segment 8, and the inner diameter of the fifth cavity segment 20 can be equal to the diameter of the fourth ejector pin segment 9.

[0072] exist Figure 1 In the closed state of the punch 14 shown, the lower end face of the ejector pin 5 is located above the first cavity section 16 and thus above the lower end face of the punch 14. The diameter of the first ejector pin section 6 of the ejector pin 5 can be equal to the diameter of the first cavity section 16 plus the radial dimension of the first ejector pin slope 10 or the second ejector pin slope 11. When the ejector pin 5 moves downward to open the two punch parts 15, that is, in the open state of the punch 14, see Figure 5a In the second punching process shown, the first push rod section 6 of the push rod 5 can be moved downwardly against the inner wall of the punch 14 that defines the first cavity section 16 , thereby preventing the lower end of the punch 14 from being broken off when the sheet metal part 4 is pressed laterally.

[0073] exist Figure 1 In the initial state of the punch system 2 shown, the punch 14 can fit the ejector pin 5 in its cavity, wherein the first ejector pin slope 10 can abut against the first cavity slope 21, and the second ejector pin slope 11 can abut against the second cavity slope 22. Therefore, when the ejector pin 5 moves downward relative to the punch 14 toward the die system 3, that is, when moving from the first cavity slope 21 to the second cavity slope 22, the first ejector pin slope 10 can abut against the first cavity slope 21, and the second ejector pin slope 11 can abut against the second cavity slope 22. Figure 3a The first punching state of the punch system 2 is shown Figure 5aWhen the second punching state of the punch system 2 shown is changed, based on the lateral or transverse extrusion of the first ejector bevel 10 and the second ejector bevel 11 on the first cavity bevel 21 and the second cavity bevel 22, respectively, the two punch parts 15 can move laterally or transversely away from each other. Here, the arrangement of two pairs of ejector bevels 10, 11 and cavity bevels 21, 22 spaced apart from each other in the axial direction of the punch 14 is advantageous because they can ensure that the two punch parts 15 can be laterally translated simultaneously in their entire axial direction without tilting or swinging. In some embodiments, for example, when the punch 14 is shorter, only one pair of ejector bevels and cavity bevels can be arranged, for example, in the middle axial position of the punch 14. In some embodiments, more than two pairs of ejector bevels and cavity bevels can be spaced apart in the axial direction of the punch 14.

[0074] Viewed in the direction away from the die system 3, the punch 14 or the two punch parts 15 may have three punch sections 23, 24, 25 in the axial direction thereof. Among them, the first punch section 23 may define a first cavity section 16 on its inner side and may have a laterally or transversely protruding protrusion, here a flange 26, on its outer side at the free end facing the die system 3. Here, the protrusion or flange 26 may be provided on all punch parts 15. In other embodiments, the protrusion or flange 26 may be provided only on a part of the punch parts 15, while the other punch parts 15 may not be provided with the protrusion or flange 26. The lateral or transverse protrusion size of the flange 26 can be set according to actual needs, and its influence is as follows: Fig.10 and Fig.13 The depth value of the undercut 102 of the joint portion 101 on the obtained composite part 100 is t U The diameter of the second punch section 24 can be greater than the diameter of the third punch section 25, so that the two can form a punch bevel 27 at the adjacent part on the outer circumference, and the diameter of the punch bevel 27 gradually decreases away from the die system 3 (i.e., in the direction away from or away from the die system 3). The punch 14 or the two punch parts 15 can be provided with a laterally protruding protrusion 28 on its outer circumference at its end away from the die system 3.

[0075] The punch system 2 can have a punch seat 29, which can have a through hole in the center for the ejector pin 5, in particular its fourth ejector pin section 9, to pass through, and in which the ejector pin 5 can be axially guided in a movable manner. The punch seat 29 can be provided with a plurality of upper feet 30 on its upper side, radially outside, by means of which pressure or a punch force can be applied to the punch seat 29 downwardly toward the die system 3 as a whole, so that the punch seat 29 or the punch system 2 moves downwardly toward the die system 3. It is also possible to apply a counter force so that the punch seat 29 or the punch system 2 moves upward away from the die system 3. The punch seat 29 can be fixedly connected to a fixing plate 31 on its lower side via a pad 33, and the fixing plate 31 can have a punch receiving portion in the center, here a through hole, in which the third punch section 25 of the punch 14 can be partially received. The punch receiving portion can be provided with a lateral recess 32 in its upper part, which can be bounded by a backing plate 33 on its upper side and can accommodate the above-mentioned protrusion 28 of the punch 14. It is important here that in the state where the punch 14 is in contact with the ejector pin 5, i.e. in the closed state of the punch 14, see Figure 1 and Figure 4 , there is a radial gap 34 between the outer periphery of the punch 14 and the fixed plate 31. The radial dimension of the radial gap 34 can be equal to or greater than the radial dimension of the first push rod inclined surface 10 and the second push rod inclined surface 11, so that the push rod 5 can move smoothly toward the die system 3 relative to the punch 14 without being stuck because the punch part 15 cannot move outward sufficiently. Based on the axial fixation and radial guidance of the protrusion 28 of the punch 14 in the lateral recess 32 of the fixed plate 31, the two punch parts 15 can only move laterally or transversely relative to the fixed plate 31. When the push rod 5 moves downward relative to the punch 14, the two punch parts 15 of the punch 14 can enter the expanded position, and the radial gap 34 disappears, see Figure 7 .

[0076] The punch system 2 can have a stop plate 35, which is arranged below the fixing plate 31 and is connected to the fixing plate 31 via a schematically indicated spring 36. During the movement of the punch holder 29 toward the die system 3, the spring 36 can be compressed until the fixing plate 31 stops on the stop plate 35 (see Figure 3a ). It is conceivable that a not-shown limiting device, such as a limiting screw, may be provided between the stop plate 35 and the fixing plate 31 to limit the maximum distance between the two.

[0077] The stop plate 35 can be provided with a punch receptacle in the center, here a through hole, in which the second punch section 24 of the punch 14 can be received and guided. The punch receptacle of the stop plate 35 can have two punch receptacle sections 50, 51 (see FIG. Figure 2a), the diameter of the first punch receiving section 50 can be greater than the diameter of the second punch receiving section 51, so that the two can form a punch receiving section bevel 37 of the stop plate 35 at the adjacent position, and the diameter of the punch receiving section bevel 37 gradually decreases away from the die system 3. The punch receiving section bevel 37 of the stop plate 35 can cooperate with the punch bevel 27 of the punch 14, see Figure 6a After the push rod 5 pushes the two punch parts 15 laterally apart into an open state, the punch bevel 27 can abut against the punch receiving portion bevel 37. Figure 8a When the punch 14 moves away from the die system 3 relative to the stop plate 35, the punch receiving portion inclined surface 37 can press the punch inclined surface 27 laterally inward, so that the two punch parts 15 approach each other and enter a closed state.

[0078] See also Figure 1 In the initial state of the punch system 2, that is, when the punch 14 and the ejector pin 5 are in contact with each other, the two punch parts 15 or their second punch sections 24 can almost rest on the inner wall of the second punch receiving section 51 defined above the stop plate 35 and be guided by it, and there is a radial gap 34 between the two punch parts 15 or their second punch sections 24 and the inner wall of the first punch receiving section 50 defined below the stop plate 35, and the radial size of the radial gap 34 is equal to (in this embodiment) or greater than the radial size of the first ejector pin inclined surface 10 and the second ejector pin inclined surface 11.

[0079] The punch system 2 may have a pressure plate 38 (or stripper plate), which may be fixed below the stop plate 35 or form a part of the stop plate 35. The pressure plate 38 may fix the sheet metal part 4 on the die system 3 for the punching process.

[0080] See also Figure 1The die system 3 may include a die seat 40 and a die 41 disposed on the die seat 40. The die 41 may include two die parts 42 separated from each other, and a die core 43, for example, in the shape of a rod, may be disposed between the two die parts 42. The two die parts 42 are formed with a step surface on the side facing each other, and the step surfaces of the two die parts 42 and the top surface of the die core 43 may be combined to form a cavity 44 open to the ejector pin 5. Here, each step surface may include a flat bottom surface flush with the top surface of the die core 43 and a side surface having an undercut 45. The undercut 45 (also referred to as a lateral or transverse depression) may be defined as follows in the present invention, that is, the undercut 45 has a first point further away from the bottom surface and a second point closer to the bottom surface, and the distance between the first point and the center of the cavity 44 (such as the longitudinal axis of the die core 43) is less than the distance between the second point and the center of the cavity 44. In some embodiments, the die 41 may include more than two separate die parts 42 , which may be arranged around a die core 43 and define the cavity 44 together therewith.

[0081] The die core 43 can be fixedly arranged on the die seat 40 and can be arranged directly below the ejector pin 5. The die core 43 can play a positioning role, that is, to ensure that the formed cavity 44 is directly below the ejector pin 5. Springs 46 can be respectively arranged between the die core 43 and the two die parts 42 and between their side walls (see Figure 8a and Figure 9a The two die parts 42 can overcome the spring rebound force when the cylinder force is applied laterally and move toward the die core 43 until a cavity 44 for stamping is formed therewith ( Figure 2a , Figure 3a , Figure 5a , Figure 6a ). The two die parts 42 can move away from each other under the action of the spring force of the spring 46 when the cylinder force is removed (see Figure 8a and Figure 9a ) in order to demold the composite part 100 after the stamping is completed.

[0082] In some embodiments, the die core 43 may be omitted, and a spring 46 may be directly disposed between the two die parts 42. In this case, other positioning methods may be used to accurately position the die parts, such as by computer control or other additional mechanical structures.

[0083] In some embodiments, at least one of the female mold parts 42 can be fixedly arranged on the female mold base 40, and the demoulding of the composite part 100 can be carried out after the other movable female mold parts 42 are moved away. At this time, there can be a step of moving the composite part 100 laterally to leave the undercut 45 of the fixed female mold part 42.

[0084] In some embodiments, at least one of the female mold parts 42 may not be provided with the undercut 45 , while the undercuts 45 of the other female mold parts 42 together form the undercut 45 of the cavity 44 .

[0085] Next reference Figures 2a to 9b The steps of performing a punching and rivet-free connection process on two stacked plate parts 4 to obtain a composite part 100 by means of the punching die 1 according to the first embodiment of the present invention are exemplarily described.

[0086] Figure 2a Step 1 is shown: the first plate 4 and the second plate 4 are laid flat on the die 41 and located above the cavity 44, and the punch system 2 is moved toward the die system 3 by the punch press until the two stacked plates 4 are pressed.

[0087] Here, the two punch parts 15 are in a closed state, the two push rod bevels 10 and 11 of the push rod 5 respectively abut against the two cavity bevels 21 and 22 of the cavity of the punch 14, and there is a radial gap 34 between the punch 14 and the fixed plate 31. The punch bevel 27 of the punch 14 is above the stop plate 35, and the punch 14 is abutted against the inner wall of the second punch accommodating portion 51 defined above the stop plate 35. The fixed plate 31 and the stop plate 35 are separated by a spring 36.

[0088] Figure 2b Two plates 4 are shown stacked in step 1 .

[0089] Figure 3a Step 2 is shown: the punch press continues to move downward, and except for the stop plate 35 and the pressure plate 38 which remain stationary, the rest of the punch system 2 continues to press downward until the fixed plate 31 stops on the stop plate 35, and at the same time, the punch 14 moves downward to punch the material of the sheet metal 4 into the cavity 44 of the die system 3 and contacts the bottom surface of the cavity 44.

[0090] At this time, the punch system 2 enters its first punching state. In this first punching state, the punch 14 has completed its axial stroke toward the die system 3, and the plate 4 has also been pressed against the bottom surface of the cavity 44 and thus completed its depth forming, but the material has not yet entered the side recess 102 of the cavity 44.

[0091] Here, the two punch parts 15 are still in a closed state, and the two push rod slopes 10 and 11 of the push rod 5 are still respectively against the two cavity slopes 21 and 22 of the cavity of the punch 14, but the punch slope 27 of the punch 14 is already at the height of the punch accommodating portion slope 37 of the stop plate 35. There is a radial gap 34 between the punch 14 and the fixed plate 31, the stop plate 35, and the pressure plate 38. The spring 36 between the fixed plate 31 and the stop plate 35 is compressed (but not visible here), but the push rod 5 has not yet moved relative to the punch 14.

[0092] Figure 3b The semi-formed sheet metal joint 101 in step 2 is shown, where it can be seen that the inner wall 103 and the outer wall 104 of the joint 101 extend substantially vertically.

[0093] Figure 4 Further shown in Figure 2a In step 1 shown, there is a radial gap 34 between the two punch parts 15 and the fixing plate 31. Figure 3a In step 2 shown, the same radial gap 34 also exists between the two punch parts 15 and the fixing plate 31 .

[0094] Figure 5a Step 3 is shown: the push rod 5 is moved downward, and the two cavity slopes 21 and 22 of the punch 14 are respectively pressed outward laterally by the two push rod slopes 10 and 11, and the push rod 5 moves the left and right punch parts 15 to both sides and opens them. At the same time, the flange 26 of the punch 14 cooperates with the cavity 44 of the die 41 to further extrude the joint part 101 of the plate 4 laterally to form a side concave 102, until the second plate 4 below is completely fitted in the cavity 44. In this way, a sink 105 that follows the shape of the cavity 44 is formed on the composite part 100, and undercuts are formed at the left and right ends of the sink 105 as shown in the figure.

[0095] Here, the two punch parts 15 enter the open state, the two push rod bevels 10 and 11 of the push rod 5 have moved downward relative to the two cavity bevels 21 and 22 of the cavity of the punch 14, the punch bevel 27 of the punch 14 has abutted against the punch accommodating portion bevel 37 of the stop plate 35, the punch 14 and the fixed plate 31, the stop plate 35, and the pressure plate 38 no longer have a radial gap 34, the spring 36 between the fixed plate 31 and the stop plate 35 is still compressed, the push rod 5 has moved downward relative to the punch 14 until their bottom surfaces are flush, and the first push rod section 6 of the push rod 5 abuts against the inner side of the first punch section 23 of the punch 14.

[0096] Figure 5b The plate joint portion 101 further formed in step 3 is shown. It can be seen that the joint portion 101 has formed a side recess 102, and the inner wall 103 and the outer wall 104 both protrude radially outward at the side recess 102. As a result, the joint portion 101 of the two plates 4 approximately forms an inverted "J" shape or an inverted Ω shape. At this time, the composite part 100 of the present invention has been manufactured.

[0097] Figure 6a Step 4 is shown, ie the first step of the demoulding step: the ejector pin 5 is moved upward to a relative height of the ejector pin 5 with respect to the punch 14 in the closed state of the punch system 2 .

[0098] Here, compared with the state of the punching die 1 in step 3, only the ejector pin 5 moves upward relative to the punch 14, and the other parts remain unchanged.

[0099] Figure 6b The same sheet metal joint region 101 of the composite component 100 as in step 3 is shown in step 4 .

[0100] Figure 7 Further shown in Figure 5a In step 3 shown in the figure, the radial gap 34 between the two punch parts 15 and the fixing plate 31 disappears as the left and right punch parts 15 move laterally outward. Figure 6a In step 4 shown, there is no radial gap 34 between the two punch parts 15 and the fixing plate 31 .

[0101] Figure 8a Step 5 is shown, which is the second step of the demoulding step: the punch moves up, but the stop plate 35 and the pressure plate 38 are pressed by the spring force of the spring 36 and do not move up, so there is an axial relative movement between the left and right punch parts 15 and the stop plate 35. At the same time, based on the lateral or transverse inward extrusion of the punch inclined surfaces 27 on the two punch parts 15 by the punch receiving portion inclined surface 37 on the stop plate 35, the left and right punch parts 15 move toward the middle until they are attached to the ejector rod 5, thereby reaching the closed state of the punch 14 again. In addition, the cylinder acting on the die 41 can be retracted to remove the cylinder force applied to the die part 42, so that the left and right die parts 42 are opened away from each other to both sides under the action of the rebound force of the spring 46, so as to demould the composite part 100 laterally.

[0102] Here, the punch system 2 returns to its Figure 1 The initial state is shown.

[0103] Figure 8b The sheet metal joint region 101 of the composite component 100 in step 5 is shown to be the same as in steps 3 and 4 .

[0104] Figure 9a Step 6, i.e. the third step of the demoulding step, is shown in which the punching machine drives the entire male die system 2 to move upward, and then the part can be taken out from the female die system 3.

[0105] Figure 9b The sheet metal joint region 101 of the composite component 100 in step 6 is shown to be the same as in steps 3 , 4 and 5 .

[0106] Fig.10 The enlarged view of the plate joint portion 101 of the composite part 100 product finally obtained by the above method is shown. Figure 3a The first axial punching process shown and Figure 5aThe joint part 101 is formed after the radial, lateral or transverse second stamping process shown. The joint part 101 has a recessed groove 105, and the recessed groove 105 has an undercut 102 formed by the flange 26 of the punch 14 on the side of the lower end. Due to the existence of the undercut 102, the outer wall 104 and the inner wall 103 of the joint part 101 do not extend vertically, that is, they both protrude radially outward at the undercut 102. Compared with the traditional TOX rivetless connection, on the one hand, based on the radial second stamping process, the undercut 102 is allowed to exist on the upper plate 4 or the inner wall 103 at the joint part 101, that is, the inner wall 104 is allowed to protrude radially outward at the undercut 102. The recessed groove 105 at the plate joint part 101 therefore has a larger t U value, and the t U The value can be set, that is, by setting the lateral displacement distance of the punch 14 in the second punching process (that is, the radial size of the first ejector bevel 10 and the second ejector bevel 11). On the other hand, since the split die 41 allows its cavity 44 to have an undercut 45, the undercut 45 can not only achieve a larger t U The value can also allow the outer side wall 104 of the joint part 101 at the undercut 45 to protrude radially outward, that is, the lower end width W1 of the joint part 101 is greater than the upper end width W2. Here, because the two concave mold parts 42 are laterally separated from each other when the composite part 100 is demolded, the joint part 101 with the outer side wall 104 protruding radially outward can be demolded smoothly.

[0107] Fig.11 and Fig.12 The second embodiment of the punching die 1 of the present invention is schematically shown and its corresponding Figure 5a and Figure 8a The steps of the stamping process of the stamping die 1 according to the first embodiment are shown. The stamping die 1 according to the second embodiment is different from the stamping die 1 according to the first embodiment only in the design of the die 41. Specifically, the die 41 of the stamping die 1 according to the second embodiment is one-piece rather than split, and a complete cavity 44 is directly formed on the one-piece die 41, but the cavity 44 is not provided with an undercut 45 for product demoulding. The punch systems 2 of the two embodiments can be designed in the same way.

[0108] Compared with the punching die 1 according to the first embodiment, when the punching process is performed using the punching die 1 according to the second embodiment, there is no step of closing and separating the two die parts 42, and other operations can be performed in the same manner.

[0109] Fig.13 The schematic diagram shows a joint portion 101 obtained by punching a sheet metal part 4 using a punching die 1 according to the second embodiment. Fig.10The difference of the joint part 101 shown is that the outer side wall 104 of the joint part 101 at the undercut 102 does not protrude radially outward, that is, the lower end width W1 of the joint part 101 is equal to its upper end width W2. However, compared with the traditional TOX rivetless connection, the second radial stamping process allows the upper plate 4 to have an undercut 102 on the joint part 101, that is, the inner side wall 104 protrudes radially outward at the undercut 102. Therefore, the groove 105 of the plate joint part 101 can also have a larger t U value, and the t U The value can be set, namely, by setting the lateral displacement distance of the punch 14 during the second punching process (ie, the radial dimensions of the first ejector rod inclined surface 10 and the second ejector rod inclined surface 11).

[0110] Fig.14a The embodiment of the application of the punching die 1 of the present invention to the rivet-free connection between the fixing point bracket 200 and the retractor bracket 201 (first plate 4) and the back plate 202 (second plate 4) on the child seat safety belt is schematically shown, and a plurality of exemplary marked joint parts 101 are formed thereon. Based on the reliable connection of the joint parts 101 of the present invention, spot welding can be well replaced by rivet-free connection.

[0111] Fig.14b Schematically shown Fig.14a 2 is a sectional view of two joints 101 between a fixing point bracket 200 (first plate 4) and a back plate 202 (second plate 4) on a child seat belt at section line AA, where it can be seen that the joints 101 are formed by the stamping die 1 according to the first embodiment as an example.

[0112] Fig.15a The schematic diagram shows an application example of the punching die 1 of the present invention for rivet-free connection between a reinforcing sheet 300 (first plate 4) and a seat pan 301 (second plate 4), on which a plurality of joints 101 are formed. Based on the reliable connection of the joints 101 of the present invention, spot welding can be well replaced by rivet-free connection.

[0113] Fig.15b Schematically shown Fig.15a A partial enlarged view of the joint area 101 in FIG.

[0114] Fig.15c Schematically shown Fig.15b 1 , a sectional view along the section line BB is shown, in which the connection point 101 is formed by way of example by the punching tool 1 according to the first exemplary embodiment.

[0115] Fig.14a and Fig.15aThe application embodiment shown is only exemplary, and it is conceivable that any two workpieces having a plate-shaped overlapping portion abutting against each other, even if they are not plate-shaped as a whole, can be connected without rivets using the punching die 1 and the punching method of the present invention.

[0116] Finally, it should be pointed out that the above embodiments are only used to understand and explain the present invention, and do not limit the protection scope of the present invention. For those skilled in the art, modifications can be made based on the above embodiments, and all these modifications do not depart from the protection scope of the present invention.

Claims

1. A stamping die, which is used to stamp stacked workpieces to form a joint, characterized in that: The stamping die has a punch system and a die system, the punch system has a punch, and the die system has a cavity, wherein the punch has at least two punch parts, the punch parts can be moved into the cavity or move away from the cavity along a first direction, and the punch parts can be moved between an open state farther away from each other and a closed state closer to each other along a second direction transverse to the first direction, wherein the punch parts can move into the cavity in the closed state and can move from the closed state away from each other into the open state in the cavity, wherein at least one of the punch parts has a protrusion on the section where it can enter the cavity that protrudes beyond the outer peripheral surface of the section in the second direction.

2. The stamping die according to claim 1, characterized in that: The punch system has a push rod, and the punch part together encloses a cavity extending in the first direction. The push rod can be at least partially accommodated in the cavity. The push rod can move between a first relative position and a second relative position relative to the punch part in the first direction. In the first relative position, the punch part is in the closed state, and in the second relative position, the punch part is in the open state.

3. The stamping die according to claim 2, characterized in that: The push pin has at least one push pin slope on its circumference which is inclined to the first direction, and the punch part has a cavity slope on its inner wall which defines the cavity and cooperates with the push pin slope. In a first relative position of the push pin relative to the punch part, the push pin slope of the push pin and the cavity slope of the punch part abut against each other, and in the process of the push pin entering a second relative position from the first relative position relative to the punch part, based on the squeezing of the push pin slope of the push pin on the cavity slope of the punch part, the punch part enters the open state from the closed state.

4. The stamping die according to claim 3, characterized in that: The ejector rod inclined surface and the cavity inclined surface have a gradually decreasing radial dimension in a direction approaching the die system.

5. The stamping die according to claim 3, characterized in that: Two pairs of the push rod inclined surfaces and the cavity inclined surfaces are arranged at intervals in the first direction.

6. The stamping die according to claim 3, characterized in that: In a first relative position of the push pin relative to the punch part, a bottom surface of the push pin facing the die system is further away from the die system than a bottom surface of the punch part facing the die system, and in a second relative position of the push pin relative to the punch part, the bottom surface of the push pin facing the die system is flush with the bottom surface of the punch part facing the die system.

7. The stamping die according to claim 3, characterized in that: The punch system comprises a fixed plate, the punch part is at least partially accommodated in a punch accommodation portion of the fixed plate, the punch part has one of a protrusion and a recess extending in the second direction on the outer periphery, and the fixed plate correspondingly has the other of the protrusion and the recess in the punch accommodation portion, the punch part is allowed to move between the closed state and the open state by guiding the protrusion in the recess, wherein, in the closed state of the punch part, there is a lateral gap between the punch part and the fixed plate.

8. The stamping die according to claim 1, characterized in that: The punch system has a stop plate, and the punch part is at least partially accommodated in the punch accommodating part of the stop plate, and the punch part has a punch bevel inclined to the first direction on their outer periphery, and the stop plate has a punch accommodating part bevel inclined to the first direction on its inner wall defining the punch accommodating part, which cooperates with the punch bevel, wherein in the open state of the punch part, the punch bevel and the punch accommodating part bevel abut against each other, wherein, by pressing the punch bevel of the punch accommodating part bevel of the stop plate against the punch bevel of the punch part, the punch part can enter the closed state from the open state.

9. A method for manufacturing a joint portion of a composite part using a stamping die according to any one of claims 1 to 8, wherein the composite part has at least two superimposed workpieces, characterized in that: The method comprises at least the following steps: Placing step: placing at least two superimposed workpieces at their superimposed positions above the cavity of the die system, The first punching step is to move the punch portion of the punch in a closed state along a first direction into the die cavity so that the material of the workpiece is squeezed into the die cavity along the first direction. Second punching step: moving the punch parts away from each other in the cavity from a closed state into an open state so that the protrusions on the punch press the material of the workpiece in a second direction transverse to the first direction, thereby producing a joint portion of the composite part.

10. A composite part, comprising at least two superimposed workpieces, characterized in that: The composite part has at least one joint portion at the overlapping portion of the workpieces, which is made using a stamping die according to any one of claims 1 to 8 or using a method according to claim 9, and the joint portion has an inner wall and an outer wall, and the inner wall has an undercut formed by a protrusion on the punch.

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