Fine Blanking Die Applied to the Forming of Step Parts

Abstract

The present invention discloses a precision stamping die for forming step parts, and relates to the technical field of forming dies; the precision stamping die comprises an upper die assembly and a lower die assembly, and a gap for placing a sheet material is provided between the upper die assembly and the lower die assembly; the precision stamping die is provided with a first station, a second station and a third station in sequence along the forward direction of the sheet material; the first station is used for punching the peripheral area of the step surface of the part, the second station is used for flattening the step surface of the part, and the third station is used for punching and forming the main plane and the step surface of the part as a whole; the technical solution provided by the present invention can improve the quality of the finished product of the part.

Description

Technical Field

[0001] The present invention relates to the technical field of fine blanking dies, in particular to a fine blanking die used for forming step parts. Background Art

[0002] For the parts of the car seat lock, some of them have step structures (such as the attached Figure 1 As shown); In the prior art, a general forming step is to use a continuous die process to form a number of parts on a sheet material, wherein the main plane (whose thickness is the same as the sheet material thickness) and the step surface (whose thickness is less than the sheet material thickness) in the step structure of the part are separately processed by precision cutting, so that there is an obvious punching interface at the connection between the contour lines corresponding to the main plane and the step surface, that is, the contour lines corresponding to the main plane and the step surface are not completely and smoothly transitioned; thus, the finished product quality of the part is poor. Summary of the Invention

[0003] The main purpose of the present invention is to provide a fine blanking die for forming step parts, aiming to improve the quality of the finished parts.

[0004] To achieve the above-mentioned purpose, the present invention proposes a precision stamping die for forming step parts, the precision stamping die comprising an upper die assembly and a lower die assembly, a gap for placing sheet material is provided between the upper die assembly and the lower die assembly; the precision stamping die is provided with a first station, a second station and a third station in sequence along the forward direction of the sheet material; the first station is used for punching the outer area of the step surface of the part, the second station is used for flattening the step surface of the part, and the third station is used for punching and forming the main plane and the step surface of the part as a whole.

[0005] The cam is fixedly mounted on the support frame, and the cam is adapted to move upwardly and downwardly relative to the support frame when the upper mold assembly is in operation.

[0006] In one embodiment, the first station includes a pre-cut punch disposed on the upper die assembly and a first concave mold cavity disposed on the concave template; when the upper die assembly and the lower die assembly perform a die closing operation, the pre-cut punch and the first concave mold cavity cooperate to punch the peripheral area of the stepped surface of the part.

[0007] In one embodiment, the pre-cut punch is fixedly connected to the upper backing plate, the pressure plate is provided with a first avoidance hole, and the pre-cut punch passes through the first avoidance hole and is slidably connected to the pressure plate; before the upper die assembly and the lower die assembly perform a die closing operation, the lower end surface of the pre-cut punch is higher than the lower end surface of the pressure plate, and the height difference between the lower end surface of the pre-cut punch and the lower end surface of the pressure plate is 0.4 - 0.8 mm.

[0008] In one embodiment, the second station includes a flattening punch disposed on the lower die assembly; when the upper die assembly and the lower die assembly perform a die closing operation, the pressure plate and the flattening punch cooperate to flatten the stepped surface of the part.

[0009] In one embodiment, the flattening punch is fixedly connected to the lower backing plate, the concave template is provided with a second avoidance hole, and the flattening punch passes through the second avoidance hole and is slidably connected to the concave template; before the upper die assembly and the lower die assembly perform a die closing operation, the upper end surface of the flattening punch is lower than the upper end surface of the concave template, and the height difference between the upper end surface of the flattening punch and the upper end surface of the concave template is 0.4 - 0.8 mm.

[0010] In one embodiment, the third station includes a forming punch disposed on the upper die assembly and a forming counter punch disposed on the lower die assembly, wherein the punching surface of the forming punch or the forming counter punch has a stepped structure; when the upper die assembly and the lower die assembly perform a die closing operation, the forming punch and the forming counter punch cooperate to integrally punch and form the main plane and the stepped surface of the part.

[0011] In one embodiment, the forming punch is fixedly connected to the upper backing plate, the pressure plate is provided with a third avoidance hole, and the forming punch passes through the third avoidance hole and is slidably connected to the pressure plate; the concave template is provided with a second concave mold cavity that is recessed inward, and the forming counter punch is slidably connected in the second concave mold cavity; before the upper die assembly and the lower die assembly perform a die closing operation, the lower end surface of the forming punch is higher than the lower end surface of the pressure plate, and the height difference between the two is 0.4 - 0.8 mm.

[0012] In one embodiment, the lower die assembly further includes a lower force transmission rod, and the upper end of the lower force transmission rod sequentially slides through the lower template and the lower backing plate and is fixedly connected to the forming counter punch.

[0013] In one embodiment, the lower die assembly further includes a hole punch, and the hole punch is fixedly connected to the lower backing plate; the forming counter punch is provided with a fourth avoidance hole, and the hole punch passes through the fourth avoidance hole and is slidably connected to the forming counter punch.

[0014] The technical solution of the present invention first punches the peripheral area of the stepped surface of the part at the first station, so as to provide sufficient space for the subsequent flattening deformation of the stepped surface of the part; then, the stepped surface of the part is flattened at the second station to make the thickness of the stepped surface lower than the thickness of the sheet material; finally, the main plane and the stepped surface of the part are integrally punched and formed at the third station. Different from the prior art in which the main plane and the stepped surface are processed by separately precision cutting the outer shape, in the present invention, since the outer shape contours of the main plane and the stepped surface are integrally precision cut, the contour lines corresponding to the main plane and the stepped surface are smoothly and integrally transitioned, and there is no contour shear surface with any punching interface, thereby achieving the purpose of improving the quality of the finished part. Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a schematic structural diagram of a part with a stepped structure in the background art;

[0017] Figure 2 It is a first schematic structural diagram (before the die closing action) of an embodiment of a fine blanking die for forming stepped parts provided by the present invention;

[0018] Figure 3 It is a second schematic structural diagram (when the die closing action) of an embodiment of a fine blanking die for forming stepped parts provided by the present invention;

[0019] Figure 4 is Figure 3 The partial enlarged view at A in.

[0020] Explanation of the Reference Numerals in the Drawings:

[0021] 100. Upper die assembly; 110. Upper template; 120. Upper backing plate; 130. Blank holding plate; 131. First relief hole; 132. Third relief hole; 140. Upper force transmission rod; 150. Pre-cut punch; 160. Forming punch;

[0022] 200. Lower die assembly; 210. Lower template; 220. Lower backing plate; 230. Die holder; 231. First die cavity; 232. Second relief hole; 233. Second die cavity; 240. Floating ejector rod; 241. Limit ring; 242. Spring member; 250. Flattening punch; 260. Forming counter punch; 261. Fourth relief hole; 270. Lower force transmission rod; 280. Hole punch;

[0023] 300. Sheet metal; 310. Part; 311. Main plane; 312. Step surface; 313. Through hole portion.

[0024] The realization, functional features and advantages of the object of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed implementation manners

[0025] Next, the technical solutions in the present invention will be clearly and completely described with reference to the accompanying drawings in the present invention. Obviously, the described ones are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0026] It should be noted that if there are directional indications (such as up, down, left, right, front, back,...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative position relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0027] In addition, it should be noted that the descriptions involving "first", "second", etc. in the present invention are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0028] In the prior art, for parts with a stepped structure (such as attached Figure 1As shown in the figure, the general forming process is to use continuous dies to process the sheet metal to form several parts. In the stepped structure of the parts, the main plane (with the same thickness as the sheet metal) and the stepped surface (with a thickness lower than that of the sheet metal) in the stepped structure are processed by separately precision cutting the outer shape, so that there is an obvious punching interface at the connection of the contour lines corresponding to the main plane and the stepped surface, that is, the contour lines corresponding to the main plane and the stepped surface are not smoothly and completely transitioned; this results in poor finished product quality of the parts.

[0029] To solve the above technical problems, the present invention proposes a fine blanking die applied to the forming of stepped parts.

[0030] Please refer to Figures 2-4 , in an embodiment of the present invention, the fine blanking die includes an upper die assembly 100 and a lower die assembly 200, and a gap for placing the sheet metal 300 is provided between the upper die assembly 100 and the lower die assembly 200; the fine blanking die is sequentially provided with a first station, a second station, and a third station along the advancing direction of the sheet metal 300; the first station is used for punching the outer peripheral area of the stepped surface 312 of the part 310, the second station is used for flattening the stepped surface 312 of the part 310, and the third station is used for integrally punching and forming the main plane 311 and the stepped surface 312 of the part 310.

[0031] The technical solution of the present invention first punches the outer peripheral area of the stepped surface 312 of the part 310 through the first station, so that there is enough lateral flattening deformation space for the subsequent stepped surface 312 of the part 310; then flattens the stepped surface 312 of the part 310 through the second station to make the thickness of its stepped surface 312 lower than the thickness of the sheet metal 300; finally, integrally punches and forms the main plane 311 and the stepped surface 312 of the part 310 through the third station. Different from the prior art in which the main plane 311 and the stepped surface 312 are processed by separately precision cutting the outer shape, in the present invention, since the outer contour of the main plane 311 and the stepped surface 312 is processed by integral precision cutting, the contour lines corresponding to the main plane 311 and the stepped surface 312 are smoothly and completely transitioned, and there is no contour shear surface with any punching interface, thereby achieving the purpose of improving the finished product quality of the part 310.

[0032] Specifically, the upper die assembly 100 includes an upper template 110, an upper backing plate 120, and a blank holder 130 that are arranged in sequence from top to bottom. The upper template 110 is fixedly connected to the upper backing plate 120, and the blank holder 130 can slide up and down relative to the upper backing plate 120. The upper die assembly 100 further includes an upper force transmission rod 140. The lower end of the upper force transmission rod 140 sequentially slides through the upper template 110 and the upper backing plate 120 and is fixedly connected to the blank holder 130. The lower die assembly 200 includes a lower template 210, a lower backing plate 220, and a cavity template 230 that are arranged in sequence from bottom to top. The lower template 210 is fixedly connected to the lower backing plate 220, and the cavity template 230 can slide up and down relative to the lower backing plate 220. The lower die assembly 200 further includes a floating ejector rod 240. The upper end of the floating ejector rod 240 sequentially slides through the lower template 210 and the lower backing plate 220 and is fixedly connected to the cavity template 230. A limit ring 241 is provided at the top end of the floating ejector rod 240, and a spring member 242 is sleeved on the floating ejector rod 240. The upper and lower ends of the spring member 242 respectively abut against the limit ring 241 and the lower backing plate 220. When the upper die assembly 100 and the lower die assembly 200 perform a die closing operation, the sheet material 300 is pressed between the blank holder 130 and the cavity template 230. With such a setting, before the die closing operation, since the cavity template 230 and the lower backing plate 220 are interconnected by the floating ejector rod 240, and the floating ejector rod 240 is sleeved with the spring member 242, the elastic force of the spring member 242 is used to make the cavity template 230 float above the lower backing plate 220. During the die closing operation, the entire upper die assembly 100 moves downward. The blank holder 130 located on the lower side will first contact the sheet material 300 and extrude the cavity template 230, so that the cavity template 230 moves downward against the elastic force of the spring member 242 until it contacts the lower backing plate 220. At this time, the blank holder 130 and the cavity template 230 cooperate to press the sheet material 300. As the entire upper die assembly 100 continues to move downward, it drives the pre-cut punch 150 and the forming punch 160 to descend to punch the corresponding position of the sheet material 300. During the process that the cavity template 230 is pressed by the blank holder 130 and moves downward until it contacts the lower backing plate 220, since the position of the flattening punch 250 installed on the lower backing plate 220 remains unchanged, it is equivalent to the flattening punch 250 moving upward relative to the cavity template 230, so that the flattening punch 250 can flatten the stepped surface 312 of the part 310 from bottom to top. In order to ensure that the blank holder 130 always maintains pressure to press the sheet material 300 during the subsequent downward movement of the upper die assembly 100, an external driving device needs to apply a pressing force towards the cavity template 230 to the blank holder 130 through the upper force transmission rod 140, and use its pressing force to ensure that the blank holder 130 always maintains pressure to press the sheet material 300. At the same time, the vertically arranged upper force transmission rod 140 can ensure that the blank holder 130 can move in the vertical direction when moving relative to the upper backing plate 120.Similarly, the vertically arranged floating ejector rod 240 can also ensure that the female mold plate 230 moves vertically downward relative to the lower backing plate 220.

[0033] Further, at least two upward force rods 140 are provided, and the at least two upward force rods 140 are symmetrically arranged on the left and right sides of the blank holder 130. With such an arrangement, by setting the at least two upward force rods 140 symmetrically, it is ensured that the pressing force applied to the blank holder 130 can be balanced in terms of left and right forces. In this embodiment, two upward force rods are provided.

[0034] Further, at least two floating ejector rods 240 are provided, and the at least two floating ejector rods 240 are symmetrically arranged on the left and right sides of the female mold plate 230. With such an arrangement, by setting the at least two floating ejector rods 240 symmetrically, it is ensured that the supporting force applied to the female mold plate 230 can be balanced in terms of left and right forces. In this embodiment, two floating ejector rods are provided.

[0035] As a preferred solution of the above embodiment, the first station includes a pre-cut punch 150 provided on the upper die assembly 100 and a first female mold cavity 231 provided on the female mold plate 230; when the upper die assembly 100 and the lower die assembly 200 perform a die closing operation, the pre-cut punch 150 is combined with the first female mold cavity 231 to punch the peripheral area of the stepped surface 312 of the part 310. It can be understood that when the sheet material 300 moves to the overlapping area between the opening area of the first female mold cavity 231 and the peripheral area of the stepped surface 312 of the part 310, since the punching surface profile of the pre-cut punch 150 is consistent with the peripheral area of the stepped surface 312 of the part 310, when the pre-cut punch 150 punches downward, its peripheral area is punched into the interior of the first female mold cavity 231, thus completing the punching of the peripheral area of the stepped surface 312 of the part 310.

[0036] Specifically, the pre-cut punch 150 is fixedly connected to the upper backing plate 120, and the blank holder 130 is provided with a first avoidance hole 131. The pre-cut punch 150 passes through the first avoidance hole 131 and is slidably connected to the blank holder 130, thus avoiding interference between the moving trajectories of the pre-cut punch 150 and the blank holder 130; before the upper die assembly 100 and the lower die assembly 200 perform a die closing operation, the lower end surface of the pre-cut punch 150 is higher than the lower end surface of the blank holder 130, and the height difference between the two is 0.4 - 0.8 mm. With such an arrangement, the height difference is used as the punching distance to ensure that after the blank holder 130 and the female mold plate 230 press the sheet material 300, as the upper die assembly 100 continues to move downward as a whole, the pre-cut punch 150 still has enough punching distance to punch the peripheral area. In this embodiment, the height difference between the lower end surface of the pre-cut punch 150 and the lower end surface of the blank holder 130 is 0.5 mm.

[0037] Further, a first lubricating oil groove (not shown in the drawings) is provided inside the pressure plate 130, and the first lubricating oil groove communicates with the sliding fit gap between the pre-cut punch 150 and the first avoidance hole 131. With such a setting, the lubricating grease is injected into the sliding fit gap between the pre-cut punch 150 and the first avoidance hole 131 by providing the first lubricating oil groove, so as to ensure smooth relative displacement between the pre-cut punch 150 and the pressure plate 130.

[0038] As a preferred solution of the above embodiment, the second station includes a flattening punch 250 provided on the lower die assembly 200; when the upper die assembly 100 and the lower die assembly 200 perform a die closing action, the pressure plate 130 and the flattening punch 250 are combined to flatten the stepped surface 312 of the part 310. With such a setting, during the die closing action, when the upper die assembly 100 moves downward as a whole to combine the pressure plate 130 with the concave template 230 to press the sheet material 300, as the upper die assembly 100 continues to move downward as a whole, the upper die assembly 100 drives the concave template 230 to overcome the elastic force of the spring member 242 so that the concave template 230 moves downward to contact the lower backing plate 220. Since the flattening punch 250 is installed on the lower backing plate 220, that is, the position of the flattening punch 250 remains unchanged during the downward movement of the concave template 230. At this time, it is equivalent to the flattening punch 250 moving upward relative to the concave template 230, so that the flattening punch 250 can flatten the stepped surface 312 of the part 310 from bottom to top, and the structure is simple and practical.

[0039] Specifically, the flattening punch 250 is fixedly connected to the lower backing plate 220, the concave template 230 is provided with a second avoidance hole 232, and the flattening punch 250 passes through the second avoidance hole 232 and is slidably connected to the concave template 230, so as to avoid interference between the moving trajectories of the flattening punch 250 and the concave template 230; before the upper die assembly 100 and the lower die assembly 200 perform a die closing action, the upper end surface of the flattening punch 250 is lower than the upper end surface of the concave template 230, and the height difference between the two is 0.4 - 0.8 mm. With such a setting, the height difference is used as the flattening distance to ensure that during the process of the concave template 230 being pushed by the upper die assembly 100 to move downward continuously, the downward movement distance of the concave template 230 is sufficient for the flattening punch 250 to flatten the stepped surface 312. In this embodiment, the height difference between the upper end surface of the flattening punch 250 and the upper end surface of the concave template 230 is 0.5 mm.

[0040] Further, a second lubricating oil groove (not shown in the drawings) is provided inside the concave template 230, and the second lubricating oil groove communicates with the sliding fit gap between the flattening punch 250 and the second avoidance hole 232. With such a setting, the lubricating grease is injected into the sliding fit gap between the flattening punch 250 and the second avoidance hole 232 by providing the second lubricating oil groove, so as to ensure smooth relative displacement between the flattening punch 250 and the concave template 230.

[0041] As a preferred solution of the above embodiment, refer to the attached Figure 4 , the third station includes a forming punch 160 provided on the upper die assembly 100 and a forming counter punch 260 provided on the lower die assembly 200, wherein the stamping surface of the forming punch 160 or the forming counter punch 260 has a stepped structure; when the upper die assembly 100 and the lower die assembly 200 perform a die closing action, the forming punch 160 and the forming counter punch 260 are combined to integrally punch and form the main plane 311 and the stepped surface 312 of the part 310. With such a setting, during the die closing action, the lower pressure plate 130 will first be combined with the concave die plate 230 to clamp the sheet material 300, and then the upper die assembly 100 continues to descend to drive the forming punch 160 to descend, so as to integrally punch and form the part 310 through the combination of the forming punch 160 and the forming counter punch 260, so as to integrally punch the main plane 311 and the stepped surface 312 of the part 310. In this embodiment, the stepped structure is provided on the stamping surface of the forming counter punch 260.

[0042] Specifically, the forming punch 160 is fixedly connected to the upper backing plate 120, the pressure plate 130 is provided with a third avoidance hole 132, and the forming punch 160 passes through the third avoidance hole 132 and is slidably connected to the pressure plate 130, so as to avoid the interference between the moving trajectories of the forming punch 160 and the pressure plate 130; the concave die plate 230 is provided with a second concave die cavity 233 recessed inward, and the forming counter punch 260 is slidably connected in the second concave die cavity 233; before the upper die assembly 100 and the lower die assembly 200 perform a die closing action, the lower end surface of the forming punch 160 is higher than the lower end surface of the pressure plate 130, and the height difference between the two is 0.4 - 0.8 mm. With such a setting, the height difference is used as the punching distance to ensure that after the pressure plate 130 and the concave die plate 230 clamp the sheet material 300, as the upper die assembly 100 continues to descend as a whole, the forming punch 160 still has enough punching distance to punch the part 310. In this embodiment, the height difference between the lower end surface of the forming punch 160 and the lower end surface of the pressure plate 130 is 0.5 mm.

[0043] Further, a third lubricating oil groove (not shown in the drawings) is provided inside the pressure plate 130, and the third lubricating oil groove communicates with the sliding fit gap between the forming punch 160 and the third avoidance hole 132; and / or, a fourth lubricating oil groove (not shown in the drawings) is provided inside the concave template 230, and the fourth lubricating oil groove communicates with the sliding fit gap between the forming counter punch 260 and the second concave mold cavity 233. With such a setting, by providing the third lubricating oil groove to inject lubricating grease into the sliding fit gap between the forming punch 160 and the third avoidance hole 132, the relative displacement between the forming punch 160 and the pressure plate 130 is ensured to be smooth; by providing the fourth lubricating oil groove to inject lubricating grease into the sliding fit gap between the forming counter punch 260 and the second concave mold cavity 233, the relative displacement between the forming counter punch 260 and the concave template 230 is ensured to be smooth.

[0044] Further, the lower die assembly 200 further includes a lower force transmission rod 270, and the upper end of the lower force transmission rod 270 sequentially slides through the lower template 210 and the lower backing plate 220 and is fixedly connected to the forming counter punch 260. With such a setting, after the forming punch 160 and the forming counter punch 260 form the part 310, the part 310 will be embedded in the second concave mold cavity 233. At this time, the lower force transmission rod 270 is driven by an external driving device to rise to lift the forming counter punch 260, so as to lift the part 310 above the upper end surface of the concave template 230, facilitating the operator to take out the part 310.

[0045] Furthermore, the lower die assembly 200 further includes a hole punch 280, and the hole punch 280 is fixedly connected to the lower backing plate 220; the forming counter punch 260 is provided with a fourth avoidance hole 261, and the hole punch 280 passes through the fourth avoidance hole 261 and is slidably connected to the forming counter punch 260. With such a setting, since some manufacturers require a through hole portion 313 to be provided on their part 310, the hole punch 280 is provided in the present application for the above reason; during the mold closing operation, when the part 310 is driven by the forming punch 160 to move to the second concave mold cavity 233, since the hole punch 280 is installed on the lower backing plate 220, that is, the position of the hole punch 280 remains unchanged during the downward movement of the forming counter punch 260. At this time, it is equivalent to the hole punch 280 moving upward relative to the forming counter punch 260, so that the hole punch 280 can process the part 310 from bottom to top to form the through hole portion 313, with a simple structure and strong practicability. In other embodiments, the through hole portion 313 can also be designed as a blind hole portion. At this time, it is only necessary to design the hole punch 280 so that there is a certain distance between its upper end surface and the lower end surface of the forming punch 160.

[0046] The stamping steps of the fine blanking die of the present application will be specifically described below in combination with the above embodiments:

[0047] Before the mold closing operation, the uploading force rod 140 presses the blank holding plate 130, so that the lower end surface of the blank holding plate 130 is 0.5 mm below the lower end surface of the pre-cut punch 150; the distance between the lower end surface of the blank holding plate 130 and the upper end surface of the concave template 230 is about 80 mm; the downlink force rod 270 supports the forming counter punch 260, so that the upper end surface of the forming counter punch 260 is basically flush with the upper end surface of the concave template 230.

[0048] During the mold closing operation, the upper die assembly 100 moves downward as a whole. The blank holding plate 130 first contacts the sheet material 300 and continues to move downward until the sheet material 300 is tightly attached to the upper end surface of the floating concave template 230; the upper die assembly 100 continues to move downward as a whole. Under the support of the uploading force rod 140, the blank holding plate 130 and the concave template 230, supported by the floating ejector rod 240, press the sheet material 300 towards each other and continue to move downward; at this time, the flattening punch 250 at the second station moves upward relative to the concave template 230 and starts to flatten the stepped surface 312 of the part 310 until the concave template 230 and the lower backing plate 220 are in mutual contact, and the stepped surface 312 is synchronously flattened and formed. At this time, the blank holding plate 130 stops moving downward relative to the concave template 230; while the pre-cut punch 150 and the forming punch 160 continue to move downward. The pre-cut punch 150 at the first station punches through the sheet material 300, that is, the peripheral area of the stepped surface 312 of the part 310, to complete the pre-cut hole; at the same time, at the third station, since the downward force applied to the forming punch 160 is greater than the upward force of the forming counter punch 260 supported by the downlink force rod 270, the forming counter punch 260 and the forming punch 160 press the part 310 towards each other and continue to move downward to complete fine blanking. At this time, the downward movement of the upper die assembly 100 stops. It should be noted that the pre-cut punch 150 and the forming punch 160 have the same downward stroke.

[0049] The upper die assembly 100 moves upward during the return stroke. After moving upward a certain distance, the uploading force rod 140 moves downward relative to the upper template 110, pushing the blank holding plate 130 downward relative to the pre-cut punch 150 and the forming punch 160 to separate the sheet material 300 stuck around the pre-cut punch 150 and the forming punch 160. At the same time, the downlink force rod 270 pushes the forming counter punch 260 upward under the action of an external driving device until the upper end surface of the forming counter punch 260 is basically flush with the upper end surface of the concave template 230, so that the forming counter punch 260 can push the part 310 out of the second concave mold cavity 233. At this time, the operator can take out the part 310. When the upper die assembly 100 moves upward until the blank holding plate 130 and the concave template 230 are separated from each other, the spring member 242, due to the lack of extrusion of the upper die assembly 100, will push the concave template 230 upward under its own elastic force to separate the concave template 230 from the lower backing plate 220 to complete the reset.

[0050] In addition, according to the above description, the peripheral area blanking is carried out from top to bottom by using the pre-cut punch 150, the flattening treatment of the stepped surface 312 is carried out from bottom to top by using the flattening punch 250, and the forming fine blanking is carried out from top to bottom by combining the forming punch 160 and the forming counter punch 260; in this way, during the repeated up and down blanking process of the part 310, one side of the part 310 is prevented from being repeatedly stressed, which is beneficial to reducing the stamping damage rate of the part 310.

[0051] Meanwhile, in the third working station, during the fine blanking process of the part 310, on the one hand, the part 310 bears the blanking force provided by the pressing of the blank holder 130 and the concave die plate 230; on the other hand, the part 310 bears the counter pressure from the forming counter punch 260, and the counter pressure of the forming counter punch 260 is provided by the lower force transmission rod 270; on the third hand, the part 310 bears the blanking force from the forming punch 160, and the blanking force of the forming punch 160 is provided by the overall downward movement of the upper die assembly 100. In this way, the part 310 in the shear zone during the fine blanking process is in a state of triaxial compressive stress, so as to improve the plasticity of the material; furthermore, the dimensional tolerance of the blanked part is small, the shape and position accuracy is high, the blanking surface is smooth, and the surface is flat.

[0052] It should be noted that other contents of the fine blanking die applied to the forming of stepped parts disclosed in the present invention are prior art and will not be elaborated here.

[0053] The above are only optional embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. All applications directly or indirectly using the present invention in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A fine blanking die applied to the forming of stepped parts, characterized in that: The fine blanking die includes an upper die assembly and a lower die assembly, and a gap for placing a sheet material is provided between the upper die assembly and the lower die assembly; The fine blanking die is sequentially provided with a first station, a second station, and a third station along the advancing direction of the sheet material; the first station is used for punching the peripheral area of the stepped surface of the part, the second station is used for flattening the stepped surface of the part, and the third station is used for integrally punching and forming the main plane and the stepped surface of the part; Specifically, the upper die assembly includes an upper template, an upper backing plate, and a blank holding plate which are sequentially arranged from top to bottom, wherein the upper template is fixedly connected to the upper backing plate, and the blank holding plate can slide up and down relative to the upper backing plate; the upper die assembly further includes an upper force transmission rod, and the lower end of the upper force transmission rod sequentially slides through the upper template and the upper backing plate and is fixedly connected to the blank holding plate; The lower die assembly includes a lower template, a lower backing plate, and a concave template which are sequentially arranged from bottom to top, wherein the lower template is fixedly connected to the lower backing plate, and the concave template can slide up and down relative to the lower backing plate; the lower die assembly further includes a floating ejector rod, and the upper end of the floating ejector rod sequentially slides through the lower template and the lower backing plate and is fixedly connected to the concave template; a limit ring is arranged at the top end of the floating ejector rod, and a spring member is sleeved on the floating ejector rod, and the upper and lower ends of the spring member respectively abut against the limit ring and the lower backing plate; When the upper die assembly and the lower die assembly perform a die closing action, the sheet material is pressed between the blank holding plate and the concave template; Among them, the third station includes a forming punch arranged on the upper die assembly and a forming counter punch arranged on the lower die assembly, wherein the punching surface of the forming punch or the forming counter punch has a stepped structure; when the upper die assembly and the lower die assembly perform a die closing action, the forming punch and the forming counter punch are combined to integrally punch and form the main plane and the stepped surface of the part; The forming punch is fixedly connected to the upper backing plate, the blank holding plate is provided with a third avoidance hole, and the forming punch passes through the third avoidance hole and is slidably connected to the blank holding plate; the concave template is provided with a second concave die cavity which is recessed inward, and the forming counter punch is slidably connected in the second concave die cavity; before the upper die assembly and the lower die assembly perform a die closing action, the lower end surface of the forming punch is higher than the lower end surface of the blank holding plate, and the height difference between the two is 0.4 - 0.8 mm; The lower die assembly further includes a lower force transmission rod, and the upper end of the lower force transmission rod sequentially slides through the lower template and the lower backing plate and is fixedly connected to the forming counter punch.

2. The fine blanking die applied to the forming of stepped parts according to claim 1, characterized in that: The first station includes a pre-cut punch arranged on the upper die assembly and a first concave die cavity arranged on the concave template; when the upper die assembly and the lower die assembly perform a die closing action, the pre-cut punch and the first concave die cavity are combined to punch the peripheral area of the stepped surface of the part.

3. The fine blanking die applied to the forming of stepped parts as claimed in claim 2, wherein: The pre-cut punch is fixedly connected to the upper backing plate. The blank holding plate is provided with a first avoidance hole, and the pre-cut punch passes through the first avoidance hole and is slidably connected to the blank holding plate. Before the upper die assembly and the lower die assembly perform the die closing action, the lower end face of the pre-cut punch is higher than the lower end face of the blank holding plate, and the height difference between the lower end face of the pre-cut punch and the lower end face of the blank holding plate is 0.4 - 0.8 mm.

4. The fine blanking die applied to the forming of stepped parts according to claim 1, wherein: The second station includes a flattening punch disposed on the lower die assembly. When the upper die assembly and the lower die assembly perform the die closing action, the blank holding plate and the flattening punch cooperate to flatten the stepped surface of the part.

5. The fine blanking die applied to the forming of stepped parts as described in claim 4, wherein: The flattening punch is fixedly connected to the lower backing plate. The concave template is provided with a second avoidance hole, and the flattening punch passes through the second avoidance hole and is slidably connected to the concave template. Before the upper die assembly and the lower die assembly perform the die closing action, the upper end face of the flattening punch is lower than the upper end face of the concave template, and the height difference between the upper end face of the flattening punch and the upper end face of the concave template is 0.4 - 0.8 mm.

6. The fine blanking die applied to the forming of stepped parts as claimed in claim 1, wherein: The lower die assembly further includes a hole punch, and the hole punch is fixedly connected to the lower backing plate. The forming counter punch is provided with a fourth avoidance hole, and the hole punch passes through the fourth avoidance hole and is slidably connected to the forming counter punch.

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