A one-step forming structure for reverse bending and edge covering of a sheet metal part

Abstract

The application relates to the sheet metal forming technology field of hardware and home appliances, and discloses a one-step forming structure for reverse bending and edge covering of a sheet metal part, which comprises an upper die assembly and a lower die assembly; the upper die assembly comprises an upper die plate and a concave die plate; the lower die assembly comprises a lower die plate, a fixed block, a bending punch and a top rod bending punch which are rotatably connected to the fixed block through connecting shafts; the fixed block is provided with a limiting structure for limiting the rotation angle of the bending punch; the lower die assembly further comprises a positioning plate and a guide plate fixed to the lower die plate; the positioning plate is provided with a first elastic element below; and the positioning plate and the guide plate are connected through a guide structure. The application has the effect of facilitating edge covering treatment of the sheet metal part.

Description

Technical Field

[0001] This application relates to the field of sheet metal forming technology for thin sheet metal parts for hardware and home appliances, and in particular to a one-time forming structure for bending and edge wrapping the reverse side of thin sheet metal parts. Background Technology

[0002] In the hardware and home appliance manufacturing industry, the edges of thin sheet metal parts often require reverse edging to enhance structural strength, eliminate sharp edges, and improve safety and aesthetics. Reverse edging refers to the process of bending and wrapping the edge of the sheet metal in the opposite direction to its front side.

[0003] Currently, the industry commonly uses a multi-step stamping process to achieve reverse edge wrapping. Typical existing technology usually requires three steps. First, using a first set of molds, the area of ​​the sheet material to be edged is bent downwards at approximately 90 degrees, forming a preliminary vertical edge. Next, in the second step, another set of molds is used to fold the aforementioned vertical edge upwards at approximately 135 degrees, making its angle exceed 90 degrees, preparing for the final edge wrapping. Finally, in the third step, a third set of molds is used to press the pre-folded edge upwards and flatten it, tightly wrapping it around the base material, completing the edge wrapping.

[0004] This traditional multi-step forming method has significant drawbacks. First, because it requires three independent stamping processes, it necessitates the design, manufacture, and maintenance of multiple sets of dedicated molds, resulting in high mold costs. Second, each part requires three clamping, positioning, and stamping processes, leading to long production cycles and low overall production efficiency. Furthermore, cumulative errors can easily occur during the multi-step transfer and positioning processes, affecting the final forming accuracy and consistency of the parts. Utility Model Content

[0005] To facilitate the edge banding of sheet metal parts, this application provides a one-time forming structure for bending and edge banding the reverse side of thin sheet metal parts.

[0006] The technical solution for a one-time forming structure for reverse bending and edge wrapping of thin sheet metal parts provided in this application is as follows: A one-time forming structure for bending and edge banding on the reverse side of a thin sheet metal part includes an upper mold assembly and a lower mold assembly. The upper mold assembly includes an upper template and a concave template. The lower mold assembly includes a lower template, a fixing block, a bending punch, and a push rod. The bending punch is rotatably connected to the fixing block via a connecting shaft. The fixing block is provided with a limiting structure to limit the rotation angle of the bending punch; The lower mold assembly further includes a positioning plate and a guide plate fixed to the lower mold plate, wherein: A first elastic element is provided below the positioning plate, and the positioning plate is connected to the guide plate through a guide structure.

[0007] Optionally, the connecting shaft is a pin, the bending punch has blind holes on both sides that mate with the pin, and the fixing block has through holes that mate with the pin.

[0008] Optionally, screw plugs are provided on both sides of the fixing block to seal the through hole.

[0009] Optionally, the limiting structure includes a limiting surface formed on the fixed block, and the bending punch contacts the limiting surface when rotating.

[0010] Optionally, the first elastic element is a spring.

[0011] Optionally, the guide structure includes a dovetail joint structure formed between the positioning plate and the guide plate.

[0012] Optionally, the lower surface of the concave template is provided with a limiting step, and the opening of the limiting step is provided with a chamfer.

[0013] Optionally, a magnet is provided on the upper surface of the positioning plate.

[0014] Optionally, the push rod is connected to the second elastic element.

[0015] Optionally, the second elastic element is a spring.

[0016] In summary, this application includes at least one of the following beneficial technical effects: 1. By combining a rotatable bending punch with an integrated die plate, the traditional multi-process process is integrated into a single stamping process, which significantly reduces the number of molds and production time, and greatly improves production efficiency; 2. Combining magnetic adsorption and elastic pressing ensures the stability of the parts during bending and edge binding, effectively improving forming accuracy and product consistency; Attached Figure Description Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application.

[0017] Figure 2 This is a schematic diagram illustrating the relative positions of the positioning plate and the guide plate in an embodiment of this application.

[0018] Figure 3 This is a schematic diagram illustrating the magnet installation position in an embodiment of this application.

[0019] Figure 4 This is a schematic diagram illustrating the fixed block structure in an embodiment of this application.

[0020] Figure 5 This is a schematic diagram illustrating the relative positions of the bending punch and the ejector pin in the embodiments of this application.

[0021] Figure 6 A schematic diagram illustrating the positioning state of the sheet metal part in the embodiments of this application.

[0022] Figure 7 This is a schematic diagram illustrating the pressing state of sheet metal parts in the embodiments of this application.

[0023] Figure 8 This is a schematic diagram illustrating the bending state of a sheet metal part in an embodiment of this application.

[0024] Figure 9 This is a schematic diagram illustrating the edge-wrapping state of the sheet metal part in the embodiments of this application.

[0025] Explanation of reference numerals in the attached figures: 1. Upper template; 2. Concave template; 3. Lower template; 4. Fixing block; 5. Bending punch; 6. Ejector pin; 7. Guide plate; 8. Positioning plate; 9. Pin; 10. Blind hole; 11. Through hole; 12. Plug; 13. First limiting surface; 14. Second limiting surface; 15. Limiting step; 16. Magnet; 17. First elastic element; 18. Second elastic element; 19. Sheet metal part. Detailed Implementation

[0026] The following is in conjunction with the appendix Figures 1-9 This application will be described in further detail.

[0027] This application discloses a one-time forming structure for bending and edge banding the reverse side of a thin sheet metal part.

[0028] A one-time forming structure for bending and edge banding the reverse side of a thin sheet metal part includes an upper die assembly and a lower die assembly. The upper die assembly includes an upper template 1 and a concave template 2 installed below it. The lower die assembly includes a lower template 3, a fixing block 4 installed on the lower template 3, a bending punch 5 located on the side of the fixing block 4, and a push rod 6 acting on the rear end of the bending punch 5. The bending punch 5 is rotatably connected to the fixing block 4 via a connecting shaft, and the fixing block 4 is provided with a limiting structure to restrict the maximum rotation angle of the bending punch 5.

[0029] The lower mold assembly comprises a positioning plate 8, a guide plate 7 fixed on the lower mold plate 3, and a first elastic element 17 placed below the positioning plate 8. The positioning plate 8 and the guide plate 7 are interlocked by a guide structure, so that the positioning plate 8 can slide vertically under the constraint of the guide plate 7.

[0030] When the mold starts working, the sheet metal part 19 is first placed on the upper surface of the positioning plate 8 and positioned. The upper mold assembly moves downward, and the concave plate 2 moves downward together with the upper plate 1. Then, the concave plate 2 contacts and presses against the sheet metal part 19, while pushing the positioning plate 8 to move downward against the force of the first elastic element 17, thereby pressing the sheet metal part 19 tightly onto the lower mold and completing the pressing.

[0031] The upper die continues to descend, and the concave die 2 pushes the bending punch 5, causing it to contact the sheet metal part 19 and perform a downward bend. When the bending punch 5 moves to a certain position, under the continuous pressure of the concave die 2 and the synergistic action of the ejector pin 6, the bending punch 5 begins to rotate around the connecting shaft.

[0032] During this rotation process, the bending punch 5 wraps around the pre-bent sheet metal edge until its rotation angle is blocked by the limiting structure on the fixing block 4. At this time, the sheet metal edge is completely folded and formed.

[0033] The connecting shaft is specifically a pin 9. Blind holes 10 are provided on the left and right side walls of the bending punch 5, and corresponding through holes 11 are provided on the fixing block 4. During assembly, the pin 9 passes through the through holes 11 of the fixing block 4 and is inserted into the blind holes 10 on both sides of the bending punch 5, thereby hinged the bending punch 5 to the fixing block 4.

[0034] During the stamping process, when the concave die 2 presses down on the bending punch 5, the bending punch 5 converts the downward vertical pressure it receives into a rotational torque around the axis of the pin 9. At this time, the pin 9 serves as a fixed center of rotation, and the bending punch 5 rotates clockwise around it. Throughout the entire rotation process, the pin 9 remains stationary within the through hole 11 of the fixed block 4, while the bending punch 5 rotates relative to the surface of the pin 9 through the blind holes 10 on both sides, thus smoothly performing the edge-sealing action.

[0035] Screw plugs 12 are provided on the left and right side walls of the fixing block 4. These screw plugs 12 are screwed in and seal both ends of the through holes 11 on the fixing block 4 for mounting the pin 9. Throughout the entire stamping cycle, the screw plugs 12 remain in a stationary state, tightly screwed onto the fixing block 4. When the bending punch 5 rotates around the pin 9, the pin 9 remains stationary within the through hole 11.

[0036] The limiting structure is specifically a limiting surface machined onto the fixed block 4. The limiting surface is located on the fixed block 4 at a position corresponding to the rotation path of the bending punch 5. When the bending punch 5 rotates around the connecting shaft to a predetermined angle, its body surface will come into contact with the limiting surface.

[0037] During the stamping process, when the upper die drives the bending punch 5 to rotate, the bending punch 5 rotates around the pin 9 axis. At the end of the rotation stroke, the predetermined surface of the bending punch 5 will make surface contact with the preset limiting surface on the fixed block 4. At this time, the limiting surface bears the impact force and torque from the bending punch 5. Since the fixed block 4 itself is rigidly fixed, the rotational movement of the bending punch 5 is immediately terminated, and the die then reaches the bottom dead center. The limiting surface includes a first limiting surface 13 and a second limiting surface 14.

[0038] The rear end of the ejector pin 6 is connected to a second elastic element 18. The second elastic element 18 provides a continuous forward thrust to the ejector pin 6, ensuring that its front end remains in contact with the rear end face of the bending punch 5.

[0039] During the stamping and hemming process, as the upper die descends and compresses the bending punch 5 to rotate, the rear end of the bending punch 5 compresses the ejector pin 6 to move backward. The retraction of the ejector pin 6 compresses the second elastic element 18 connected to it, storing energy. When the upper die completes the hemming and begins its return stroke, the pressure applied to the bending punch 5 disappears.

[0040] At this point, the compressed second elastic element 18 begins to release energy, pushing the ejector rod 6 forward. The forward-moving ejector rod 6 then pushes the bending punch 5, causing it to rotate counterclockwise around the connecting shaft until it returns to its initial ready position. Both the first elastic element 17 and the second elastic element 18 are springs.

[0041] A dovetail fit structure is provided between the positioning plate 8 and the guide plate 7. This structure consists of a dovetail tenon formed on the positioning plate 8 and a dovetail groove formed on the guide plate 7 that interlock with each other, maintaining a sliding fit clearance between them.

[0042] Magnets 16 are embedded in the upper surface of the positioning plate 8. These magnets 16 are partially embedded in the body of the positioning plate 8, and their adsorption surface is basically flush with the upper surface of the positioning plate 8, so that they directly face the sheet metal part 19 to be processed.

[0043] When placing the sheet metal part 19, the operator places the part on the upper surface of the positioning plate 8. At this time, the magnet 16 immediately attracts the sheet metal part 19, stabilizing it in the correct position beforehand and effectively preventing the part from tilting or slipping due to one side being suspended. Throughout the stamping process, even when the positioning plate 8 is pressing down, the attractive force of the magnet 16 remains, helping the material resist the lateral slippage that may occur in the early stages of bending. After stamping is completed and the positioning plate 8 is reset, the operator can remove the finished part by applying a force greater than the magnetic attraction force.

[0044] A limiting step 15 is formed on the lower surface of the concave template 2. The entry edge of the limiting step 15 is chamfered, so that the opening of the step forms a guiding slope.

[0045] During the stamping process, the upper die assembly moves downwards. In the initial stage of die closing, the chamfer at the opening of the limiting step 15 on the lower surface of the die plate 2 first approaches the part or the lower die assembly. The chamfered surface makes contact first, guiding the die plate 2 and the lower die assembly to be precisely aligned. As the upper die continues to descend, the vertical side of the limiting step 15 finally contacts the upper surface of the bending punch 5, forming a hard limit. The die reaches the bottom dead center, at which point the edge-sealing action is completed and the forming thickness is precisely controlled.

[0046] The implementation principle of the one-time forming structure for reverse bending and edge banding of thin sheet metal parts in this application embodiment is as follows: When the mold is working, the sheet metal part 19 is first placed on the upper surface of the positioning plate 8, and the magnet 16 attracts and fixes the part; the upper mold moves downward, the concave plate 2 contacts the part and presses the positioning plate 8, so that it compresses the first elastic element 17 downward, realizing the pressing; then the concave plate 2 pushes the bending punch 5, so that it rotates around the pin 9, and pre-bending the part; the upper mold continues to move downward, the concave plate 2 forcibly presses down the bending punch 5, so that it continues to rotate clockwise around the pin 9 as the axis, until the bending punch 5 contacts the limiting surface of the fixing block 4, the rotation stops, and the edge banding is completed; during the process, the ejector rod 6 compresses the second elastic element 18 to store energy; when the upper mold returns, the second elastic element 18 is released, pushing the ejector rod 6 to reset the bending punch 5 counterclockwise, and at the same time the first elastic element 17 pushes the positioning plate 8 to carry the finished part back to the initial position.

[0047] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A one-time forming structure for bending and edge-sealing the reverse side of a thin sheet metal part, comprising an upper mold assembly and a lower mold assembly, wherein the upper mold assembly includes an upper template and a concave template, and the lower mold assembly includes a lower template, a fixing block, a bending punch, and an ejector pin, characterized in that: The bending punch is rotatably connected to the fixed block via a connecting shaft; The fixing block is provided with a limiting structure to limit the rotation angle of the bending punch; The lower mold assembly further includes a positioning plate and a guide plate fixed to the lower mold plate, wherein: A first elastic element is provided below the positioning plate, and the positioning plate is connected to the guide plate through a guide structure.

2. The one-time forming structure for reverse bending and edge wrapping of thin sheet metal parts according to claim 1, characterized in that: The connecting shaft is a pin, and the bending punch has blind holes on both sides that cooperate with the pin. The fixing block has through holes that cooperate with the pin.

3. The one-time forming structure for reverse bending and edge wrapping of thin sheet metal parts according to claim 2, characterized in that: The fixing block is provided with screw plugs on both sides to seal the through hole.

4. The one-time forming structure for reverse bending and edge wrapping of thin sheet metal parts according to claim 1, characterized in that: The limiting structure includes a limiting surface formed on the fixed block, and the bending punch contacts the limiting surface when rotating.

5. The one-time forming structure for reverse bending and edge wrapping of thin sheet metal parts according to claim 1, characterized in that: The first elastic element is a spring.

6. The one-time forming structure for reverse bending and edge wrapping of thin sheet metal parts according to claim 1, characterized in that: The guide structure includes a dovetail joint structure formed between the positioning plate and the guide plate.

7. The one-time forming structure for reverse bending and edge wrapping of thin sheet metal parts according to claim 1, characterized in that: The lower surface of the concave template is provided with a limiting step, and the opening of the limiting step is provided with a chamfer.

8. The one-time forming structure for reverse bending and edge wrapping of thin sheet metal parts according to claim 1, characterized in that: The upper surface of the positioning plate is provided with magnets.

9. The one-time forming structure for reverse bending and edge wrapping of thin sheet metal parts according to claim 1, characterized in that: The push rod is connected to the second elastic element.

10. The one-time forming structure for reverse bending and edge wrapping of thin sheet metal parts according to claim 9, characterized in that: The second elastic element is a spring.

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