Shell forming device

Abstract

This utility model relates to the field of machining and discloses a shell forming device, including a stretching mechanism for stretching a sheet into a shell and a connecting part, a punching mechanism for machining explosion-proof holes on the stretched shell, and a cold forging mechanism for machining auxiliary structures at the edges of the explosion-proof holes. The auxiliary structures facilitate integration with explosion-proof valves. By setting a cold forging mechanism after the punching mechanism, this utility model allows for the machining of auxiliary structures at the edges of the explosion-proof holes during shell processing, thereby increasing the bonding force with the explosion-proof valve during installation, improving the weld's strength and explosion-proof capability, and enhancing safety.

Description

Technical Field

[0001] This utility model relates to the field of machining, and in particular to a shell forming device. Background Technology

[0002] Some existing housing structures (especially metal housings such as power battery housings) are formed into a basic shape through extrusion and stretching during processing, and the housing is completed after trimming. In order to improve the safety of the housing during use, it is necessary to form an explosion-proof hole at the bottom of the housing so that explosion-proof valves and other explosion-proof measures can be added at the explosion-proof hole, thereby delaying the time for danger to occur if abnormalities occur during the use of the housing.

[0003] The explosion-proof hole is usually formed by stamping using a mold. After the shell is formed, the explosion-proof valve is installed at the explosion-proof hole by welding or other methods. However, although the explosion-proof hole formed by stamping has a flat cut after shaping, making it easier to process, it requires additional positioning fixtures when connecting the explosion-proof valve and the explosion-proof hole. This increases the welding complexity and causes inconvenience to the welding work. Utility Model Content

[0004] In view of the shortcomings of the prior art, the technical problem to be solved by this utility model is to provide a shell forming device to solve the problem that the flush break formed after the existing explosion-proof hole processing causes inconvenience to the installation of explosion-proof valves.

[0005] To solve the above-mentioned technical problems, the present invention adopts a technical solution as follows: a shell forming device is provided for processing shells, the shells including bottom walls and side walls, the shell forming device sequentially including a stretching mechanism for stretching a sheet into a shell and a connecting part, a punching mechanism for processing explosion-proof holes on the stretched shell, and a cold forging mechanism for processing auxiliary structures on the edge of the explosion-proof holes, the auxiliary structures facilitating the addition of an explosion-proof valve.

[0006] Furthermore, the auxiliary structure includes a stepped groove that extends from the edge of the explosion-proof hole along the thickness direction of the bottom wall of the housing from the outside of the housing to the inside of the housing and gradually narrows radially toward the center to form a stepped shape; the cold forging mechanism corresponds to the stepped groove to form a cold forging structure and a pressing part for pressing the bottom wall onto the cold forging structure to extrude and form the stepped groove on the bottom wall of the housing.

[0007] Furthermore, the cold-forging structure has a first support surface for supporting the bottom wall of the shell and a forming protrusion protruding from the first support surface and consistent with the contour of the stepped groove, and the pressing part has a first pressing surface adapted to the inward side of the bottom wall of the shell.

[0008] Furthermore, the stepped groove includes at least a first groove segment, which forms a first groove surface at the explosion-proof hole, and the forming protrusion includes a first protrusion adapted to the first groove surface; the stepped groove also includes a second groove segment, the first groove segment, the second groove segment, and the explosion-proof hole are sequentially connected along the thickness direction of the bottom wall and gradually narrow, the second groove segment forms at least a second groove surface at the explosion-proof hole, and the forming protrusion also includes a second protrusion adapted to the second groove surface; the cold forging mechanism is provided with a first cold forging mold, a second cold forging mold, and a third cold forging mold corresponding to the stepped groove, and a first support surface is formed on the first cold forging mold, the first protrusion is formed on the first support surface of the second cold forging mold, the second protrusion is formed on the first support surface of the third cold forging mold, and a first pressing surface is provided on the first cold forging mold, the second cold forging mold, and the third cold forging mold.

[0009] Furthermore, the first cold heading mold, the second cold heading mold, and the third cold heading mold all include a first upper mold portion and a first lower mold portion; the bottom of the first upper mold portion has a first punch for vertical telescopic movement and a first limiting post for pressing against the top surface of the first upper mold portion, and the bottom surface of the first punch is configured as a first pressing surface; the top of the first lower mold portion is recessed with a cold heading cavity for the first punch to pass through vertically therein, and the bottom wall of the cold heading cavity is configured as the first supporting surface.

[0010] Furthermore, the stretching mechanism has a stretching cavity adapted to the shape of the outer wall of the shell and a forming part for squeezing the sheet into the stretching cavity and pressing the sheet to form the inner wall of the shell; the stretching cavity is provided in multiple ways and the depth is distributed from shallow to deep; the forming part is provided in multiple ways corresponding to each stretching cavity and cooperates with each stretching cavity to stretch the sheet so that the shell and the connecting part are gradually stretched and shaped.

[0011] Furthermore, each of the stretching cavities forms a second forming cavity for extruding and stretching the sheet material between itself and the corresponding forming part; each of the second forming cavities includes a bottom wall cavity for adapting to the bottom wall of the shell, a transition cavity, a side wall cavity for adapting to the side wall of the shell, and a connecting cavity for adapting to the connecting part; the width of each bottom wall cavity decreases sequentially until it matches the contour of the bottom wall of the shell, the width of each transition cavity decreases sequentially until it disappears and is inclined relative to the bottom wall cavity, the width of each side wall cavity increases sequentially until it matches the contour of the side wall of the shell and is perpendicular to the bottom wall cavity, and the connecting cavity gradually tilts from horizontal and decreases in width sequentially until it matches the contour of the connecting part.

[0012] Furthermore, the stretching mechanism includes a plurality of stretching dies, and a plurality of stretching cavities and forming portions are sequentially formed on each stretching die; each stretching die includes a second upper die portion and a second lower die portion; the second upper die portion is configured as the forming portion and has a second punch for vertical telescopic movement and an inner extrusion ring for extruding to form a connecting portion, the second punch having an inner forming surface corresponding to the inner wall of the housing; the top of the second lower die portion is recessed with the stretching cavity for the second punch to pass through vertically therein, the inner forming surface and the stretching cavity surrounding to form the second forming cavity.

[0013] The shell forming device of this utility model also includes a trimming mechanism for removing the connecting material from the shell on which the auxiliary structure has been processed, a secondary punching mechanism for reprocessing the explosion-proof holes after the cold heading mechanism, and a shaping mechanism for modifying the shape of the shell.

[0014] Furthermore, the shell forming device of this utility model also includes a storage section for stacking and storing the material sheets, a conveying device for conveying the material sheets to the stretching mechanism, a transfer device for sequentially transferring the material sheets from the storage section to the conveying device, and a detection device for detecting each material sheet passing through the conveying device.

[0015] The shell forming device of this utility model has at least the following beneficial effects: by setting a cold heading mechanism after the punching mechanism, an auxiliary structure is processed at the edge of the explosion-proof hole during shell processing, thereby increasing the bonding force with the explosion-proof valve when installing the explosion-proof valve, improving the firmness and explosion-proof capability after welding, and enhancing safety. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the shell forming device of this utility model; Figure 2 This is a front sectional view of the shell forming device of this utility model; Figure 3 This is a schematic diagram of the product after the stretching mechanism of this utility model has been processed. Figure 4 This is a front sectional view of the tensioning mechanism of this utility model; Figure 5 This is a schematic diagram of the structure of the first stretching die of this utility model; Figure 6 This is a partial cross-sectional view showing the separation of the second punch of each die from the stretching cavity in the stretching mechanism of this utility model; Figure 7 This is a partial front sectional view of the punching mechanism of this utility model; Figure 8 This is a partial front sectional view of the cold forming mechanism of this utility model; Figure 9 This is a partial front sectional view of the first cold heading mold of this utility model; Figure 10 This is a partial front sectional view of the second cold heading mold of this utility model; Figure 11 This is a partial front sectional view of the third cold heading mold of this utility model; Figure 12 This is a front sectional view of the edge-cutting mechanism of this utility model; Figure 13 This is a front sectional view of the secondary punching mechanism of this utility model; Figure 14 This is a partial front sectional view of the secondary punching mechanism of this utility model; Figure 15 This is a front sectional view of the shaping mechanism of this utility model; Figure 16 This is a partial front sectional view of the shaping mechanism of this utility model. The meanings of the labels in the attached diagram are as follows: Material sheet 1, bottom wall 11, side wall 12, connecting section 13, edge section 141, side wall section 142, bottom wall section 143, explosion-proof hole 15, bottom machine base 21, top machine base 22, stretching mechanism 3, stretching cavity 3a, second fixed plate 31, second punch 32, bottom surface 321, transition surface 322, vertical surface 323, inner extrusion ring 33, connecting surface 331, second lower template 34, second lower ejector pin 35, second die pad 36, second die 37, connecting cavity wall 371, vertical Cavity wall 372, transition cavity wall 373, bottom cavity wall 374, second ejector pin 38, punching mechanism 4, third fixing plate 41, third punch 42, third limiting post 43, first punching post 431, third pressing surface 432, third lower template 44, third die pad 45, third die 46, third positioning groove 461, third pad block 462, third clearance hole 463, step groove 5, cold heading mechanism 6, first fixing plate 61, first punch 62, first pressing surface 621, first limiting post 63. First lower template; 64. First die pad; 65. First die; 66. First positioning groove; 661. First pad block; 662. First support surface; 663. First protrusion; 671. First clearance hole; 672. Second protrusion; 673. Second clearance hole; 674. Trimming mechanism; 7. Fourth fixing plate; 71. Fourth limiting post; 72. Fourth punch; 73. Fourth lower template; 74. Rail surface; 741. Fourth die pad; 75. Fourth ejector pin; 76. Secondary punching mechanism; 8. Fifth fixing plate; 81. 82. Fifth punch, 821. Second punching post, 822. Fifth pressing surface, 83. Fifth limiting post, 84. Fifth lower template, 85. Fifth die pad, 86. Fifth positioning groove, 87. Fifth pad block, 88. Third protrusion, 881. Second clearance hole, 882. Forming mechanism, 9. Sixth fixing plate, 91. Sixth limiting post, 92. Sixth punch, 93. Sixth lower template, 94. Sixth die pad, 95. Sixth die, 96. Sixth positioning groove, 961. Sixth pad block, 962. Fourth protrusion, 963. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings.

[0018] The shell forming device of this utility model is used to process a shell, which includes a bottom wall 11 and side walls 12. The bottom wall 11 is rectangular, and the side walls 12 are arranged around the edge of the bottom wall 11 to form a rectangular frame structure.

[0019] Please see Figures 1 to 16The shell forming device of this utility model includes, in sequence, a storage section for stacking and storing sheet materials 1, a conveying device for conveying sheet materials 1 to a stretching mechanism 3, a transfer device for sequentially transferring sheet materials 1 from the storage section to the conveying device, a detection device for detecting each sheet material 1 passing through the conveying device, a stretching mechanism 3 for stretching sheet materials 1 into a shell and a connecting part 13, a punching mechanism 4 for machining explosion-proof holes on the stretched shell, a cold forging mechanism 6 for machining auxiliary structures on the edges of the explosion-proof holes, a trimming mechanism 7 for removing the connecting part 13 from the shell with the auxiliary structures, a secondary punching mechanism 84 for re-machining the explosion-proof holes machined by the cold forging mechanism 6, and a shaping mechanism 9 for trimming the shape of the shell. The transfer device also transfers sheet materials 1 from the conveying device to the stretching mechanism 3, and the entire shell forming device is mounted on a machine base.

[0020] In this embodiment, the storage section is a material chopper, on which the material sheets 1 are stacked vertically. The conveying device is a conveyor table, which can be any type of conveyor table with conveying function. The transfer device is a sheet separator, which transfers the individual material sheets 1 from the material chopper to the conveyor table. The detection device is a CCD detector, a visual inspection instrument, used to detect whether there are defects in the material sheets 1. The material sheets 1 can then be mechanically transferred to various mechanisms.

[0021] Please see Figures 4 to 6 The stretching mechanism 3 has a stretching cavity 3a adapted to the shape of the outer wall of the shell, and a forming part for extruding the sheet 1 into the stretching cavity 3a and compressing the sheet 1 to form the inner wall of the shell. In use, the sheet 1 is transferred into the stretching cavity 3a, and through the compression and stretching of the forming part, the sheet 1 is stretched into a cuboid structure. To avoid problems such as breakage of the sheet 1 due to stress concentration during the stretching process, multiple stretching cavities 3a are provided, with depths ranging from shallow to deep. Multiple forming parts are provided corresponding to each stretching cavity 3a, and each part cooperates with each stretching cavity 3a to stretch the sheet 1, gradually stretching and shaping the shell and the connecting part 13. Thus, the sheet 1 is stretched and compressed in multiple stages, and through distributed deformation, the stress distribution is gradually adjusted, avoiding excessive deformation that could cause cracking, wrinkling, etc., thereby improving the yield rate and reducing the scrap rate.

[0022] The stretching mechanism 3 includes multiple stretching dies arranged sequentially on a machine base. For example, the stretching mechanism 3 may have five dies. Each stretching die has a stretching cavity 3a and a forming part, resulting in five stretching cavities 3a and five forming parts. Initially, the stretching cavities 3a and the forming parts are separated. The sheet material 1 is placed on the stretching die, facing the stretching cavity 3a. The forming part gradually presses and extends into the stretching cavity 3a to compress and stretch the sheet material 1. Once the forming part is in place within the stretching cavity 3a, a second forming cavity is formed between each stretching cavity 3a and its corresponding forming part, compressing and stretching the sheet material 1. The sheet material 1 will then conform to the shape of the second forming cavity as it is formed.

[0023] Each stretching die includes a second upper die and a second lower die. The machine base includes a bottom machine platform 21 and a top machine platform 22. Each second upper die is sequentially mounted on the top machine platform 22, and each second lower die is mounted on the bottom machine platform 21. Each second upper die includes a second fixed plate 31 connected to the top machine platform 22, a second punch 32 mounted on the top machine platform 22 and vertically moving through a first fixed plate 61 or directly connected to the second fixed plate 31, and an inner extrusion ring 33 connected to the second fixed plate 31 and located around the second punch 32. The second upper die is configured as a forming part. The inner extrusion ring 33 is driven by a press and can move vertically. The inner extrusion ring 33 has a frame-shaped structure and its inner side is vertically continuous. The inner extrusion ring 33 is used to extrude the sheet material 1 and form a connecting part 13 on the extruded portion of the sheet material 1. The second punch 32 is vertically telescopic and driven by a separate press. Therefore, the second punch 32 is movably inserted inside the inner extrusion ring 33. The second punch 32 has an inner forming surface corresponding to the inner wall of the housing. Each stretching die has a different inner forming surface, and the height of each inner forming surface increases from low to high with the stretching cavity 3a. The outer wall of the second punch 32 includes a horizontal bottom surface 321, transition surfaces 322 that slope upwards and outwards from each side of the bottom surface 321, and a vertical surface 323 that extends vertically upwards from the top of the transition surface 322. The bottom surface 321, transition surface 322, and vertical surface 323 together constitute the inner forming surface. A connecting surface 331 is formed at the bottom of the inner extrusion ring 33.

[0024] The second lower die section includes a second lower template 34 connected to the bottom machine base 21 and hollow on its inner side, extending vertically through it; a second lower ejector rod 35 mounted on the top machine base 22 and movably passing through the inner side of the second lower template 34; a second die pad 36 connected to the top of the second lower top plate; a second die 37 fixedly connected to the top of the second lower template 34; and a second ejector rod 38 extending vertically through the inner sides of the second lower template 34 and the die. The second lower ejector rod 35 is used to drive the second ejector rod 38 to move vertically, so that the second top plate moves to a position that facilitates stretching the sheet 1 and ejects the stretched sheet 1 upwards after stretching is completed. A spring structure can be provided on the second lower ejector rod 35 to provide a certain buffering effect when the second punch 32 presses against the second ejector rod 38. A groove is formed vertically in the middle of the die, and the second ejector rod 38 is located in the groove. When the second ejector pin 38 is positioned to facilitate the stretching of the sheet 1, a stretching cavity 3a is recessed between the inner wall of the groove of the die and the top surface of the second ejector pin 38 relative to the top surface of the second lower die, for the second punch 32 to pass through vertically therein. The stretching cavity 3a includes a connecting cavity wall 371, a vertical cavity wall 372, a transition cavity wall 373, and a bottom cavity wall 374 formed by the top surface of the second ejector pin 38. When the inner forming surface mates with the second punch 32 in the stretching cavity 3a, the inner forming surface and the stretching cavity 3a surround to form the second forming cavity. Each of the second forming cavities includes a bottom wall cavity 11 for fitting to the bottom wall 11 of the housing, a transition cavity for stretching the sheet 1 to an inclined position, a side wall cavity for fitting to the side wall 12 of the housing, and a connecting cavity for fitting to the connecting part 13. The bottom wall 11 cavity is formed by the bottom cavity wall 374 and the bottom surface 321; the transition cavity is formed by the transition cavity wall 373 and the transition surface 322; the vertical cavity is formed by the vertical cavity wall 372 and the vertical surface 323; and the connecting cavity is formed by the connecting cavity wall 371 and the connecting surface 331. The inner extrusion ring 33 is adapted to the connecting cavity and forms part of the connecting cavity. The width of each bottom wall 11 cavity decreases sequentially until it matches the outline of the bottom wall 11 of the shell; the width of each transition cavity decreases sequentially until it disappears and is inclined relative to the bottom wall 11 cavity; the width of each side wall cavity increases sequentially until it matches the outline of the side wall 12 of the shell and is perpendicular to the bottom wall 11 cavity; and the connecting cavity gradually slopes from horizontal and decreases in width sequentially until it matches the outline of the connecting part 13.

[0025] Please see Figure 5 and Figure 6Specifically, five stretching dies are used as an example, and are sequentially designated as the first stretching die, the second stretching die, the third stretching die, the fourth stretching die, and the fifth stretching die. In the first stretching die, the bottom wall 11 of the inner extrusion ring 33 is horizontal so that the connecting surface 331 is horizontal. Correspondingly, the connecting cavity wall 371 has a horizontal section consistent with the connecting surface 331 and an inclined section that slopes upward and outward. In the second, third, fourth, and fifth stretching dies, the bottom wall 11 of the inner extrusion ring 33 slopes upward and outward, and gradually becomes shorter from the second stretching die to the fourth stretching die. The thickness of the inner extrusion ring 33 also gradually decreases until the inner extrusion ring 33 is absent in the fifth stretching die. The vertical surface 323 increases in height from the first to the fifth stretching die in the vertical direction, and the depth of the vertical cavity wall 372 increases accordingly. The top of each vertical cavity wall 372 is sloping upward and outward in a wide-mouth shape, so that the sheet 1 is gradually deepened during the extrusion process. The bottom of the vertical cavity wall 372 is vertical, and the wide-mouth shape allows the sheet 1 to be gradually extruded from horizontal to sloping and finally vertical. The transition surface 322 is sloping and has the greatest width from the first to the fifth stretching die, and the slope gradually decreases and the width decreases until it is almost non-existent and almost flush with the vertical surface 323, forming the side wall 12. The transition cavity wall 373 can be vertical or sloping downward and outward, so as to only have a transitional effect on the extrusion of the sheet 1 and minimize the extrusion of the sheet 1 from the side facing the bottom surface 321, thereby avoiding the sheet 1 to a certain extent. The bottom surface 321 is horizontal and its width gradually decreases from the first stretching die to the fifth stretching die until it matches the size of the bottom wall 11 of the shell.

[0026] Please refer to the following instructions during processing: Figure 3The sheet material 1 is sequentially transferred by the robotic arm to the top surface of each of the second lower dies. From the outside to the inside, an edge region, a main stretching region, a transition region, and a secondary stretching region are formed on the sheet material 1. The edge region corresponds to the connecting cavity, the main stretching region corresponds to the vertical cavity, the transition region corresponds to the transition cavity, and the secondary stretching region corresponds to the bottom wall cavity 11. Then, the second upper die moves, causing the inner extrusion ring 33 and the second punch 32 to gradually approach the sheet material 1 until the inner forming surface begins to extrude the various regions of the sheet material 1. Each stretching cavity 3a and the corresponding forming part stretch the sheet material 1 through mutual extrusion, gradually forming an edge segment 141 in the edge region of the sheet material 1, forming a side wall segment 142 that is adapted to the side arm of the shell in the main stretching region, forming a side wall segment 142 in the transition region that is part of the main stretching region, and forming a bottom wall segment 143 that is adapted to the bottom wall 11 of the shell in the secondary stretching region. Each stretching cavity 3a cooperates with the corresponding forming part to form a second forming cavity. Each second forming cavity sequentially extrudes and stretches the sheet 1, causing the edge region of the sheet 1 to be extruded and stretched, and the angle between it and the secondary stretching region gradually decreases from 180° to an obtuse angle. The width of the edge region gradually narrows to form an edge segment 141. The part of the edge region close to the main stretching region gradually deforms with the main stretching region to form a part of the side wall segment 142. The main stretching region is extruded and stretched, and the angle between it and the secondary stretching region is 90°, and the width gradually increases to form the side wall segment 142. The transition region is extruded and stretched, and the angle between it and the secondary stretching region gradually decreases from 180° to 90°, and the width gradually decreases until it is completely processed with the main stretching region to form the side wall segment 142. The edges of the secondary stretching region are extruded and stretched, and the edges gradually deform with the transition region to form a part of the side wall segment 142. The remaining part of the secondary stretching region gradually decreases to form the bottom wall segment 143. From this point on, the shape of the shell has been initially formed, with a bottom wall 11, side walls 12, and connecting part 13.

[0027] Please see Figure 7The punching mechanism 4 includes a punching die, which includes a third upper die mounted on a top machine base 22 and a third lower die mounted on a bottom machine base 21. The third upper die includes a third fixed plate 41 connected to the top machine base 22 and a third punch 42 mounted on the third fixed plate 41. The third punch 42 can move vertically relative to the third fixed plate 41, and the bottom of the third fixed plate 41 also has a third limiting post 43 for supporting the third lower die. The third punch 42 is installed between the third limiting posts 43. The third punch 42 has a first pressing surface 621 for pressing against the bottom wall 11 of the housing and a first punching post 431 located inside the first pressing surface 621 and corresponding to the position of the explosion-proof hole on the bottom wall 11. The horizontal cross-sectional shape and size of the first punching post 431 are consistent with the shape and size of the explosion-proof hole and protrude downward from the third pressing surface 432. The first punching post 431 can move vertically independently relative to the third pressing surface 432, so that after the third pressing surface 432 is pressed against the bottom wall 11 of the housing, the first punching post 431 quickly punches out from the bottom and punches out an explosion-proof hole on the bottom wall 11; or the first punching post 431 can be fixed relative to the third pressing surface 432, so that the third pressing surface 432 and the first punching post 431 always move together.

[0028] The third lower die includes a third lower template 44 fixedly mounted on the bottom machine base 21, a third die pad 45 fixedly mounted on the top surface of the third lower template 44, and a third die 46 fixedly mounted on the top of the third die pad 45. The top surface of the third die 46 is horizontal and serves to support the third limiting post 43. A third positioning groove 461 is recessed on the top surface of the third die 46, and a third pad 462 is provided in the third positioning groove 461. The top surface of the third pad 462 is horizontal to support the bottom wall 11 of the housing. A third clearance hole 463 is provided on the top surface of the third pad 462 at a position corresponding to the first punch post 431. The first punch post 431 is clearance hole 463 formed during stamping by punching the explosion-proof hole. When the third punch 42 penetrates into the third positioning groove 461, a third forming cavity that matches the contour of the inner and outer walls of the housing is formed between the third punch 42 and the inner wall of the third positioning groove 461. Preferably, the third lower die also has a push rod located below the third pad 462, for pushing the third pad 462 upward after punching to facilitate the robotic arm to grip the shell with the explosion-proof hole machined. An anti-disengagement block can be provided on the third pad 462, and an anti-disengagement buckle can be provided in the third positioning groove 461. After the push rod pushes the third pad 462 upward a certain distance, the anti-disengagement block abuts against the anti-disengagement buckle to prevent the third pad 462 from disengaging from the third positioning groove 461.

[0029] In use, the housing material connecting part 13 faces the third punch 42 and the bottom wall 11 is inserted into the third positioning groove 461 to position the housing. Then the third punch 42 moves downward and gradually penetrates into the housing until the punching is completed.

[0030] Please see Figures 8 to 11 A cold forging mechanism 6 is mounted on a base for machining the auxiliary structure described above on the edge of the explosion-proof hole. To increase the bonding force between the explosion-proof hole and the explosion-proof valve, the auxiliary structure includes a stepped groove 5 that extends radially from the edge of the explosion-proof hole along the thickness direction of the bottom wall 11 of the housing, from the outside of the housing to the inside, and gradually narrows towards the center. The stepped groove 5 includes at least a first groove segment, which forms a first groove surface at the explosion-proof hole. In another embodiment, the stepped groove 5 further includes a second groove segment, the first groove segment, the second groove segment, and the explosion-proof hole being sequentially connected along the thickness direction of the bottom wall 11 and gradually narrowing, the second groove segment forming at least a second groove surface at the explosion-proof hole. Correspondingly, the cold forging mechanism 6 forms a cold forging structure corresponding to the stepped groove 5 and a pressing portion for pressing the bottom wall 11 onto the cold forging structure to extrude the stepped groove 5 onto the bottom wall 11. The cold forging structure has a first support surface 663 for supporting the bottom wall 11 of the housing and a forming protrusion protruding from the first support surface 663 and conforming to the contour of the stepped groove 5. In one embodiment, the shaped protrusion includes at least a first protrusion 671 adapted to the first groove surface; in another embodiment, the shaped protrusion further includes a second protrusion 673 adapted to the second groove surface; the pressing portion has a first pressing surface 621 adapted to the inward side of the bottom wall 11 of the housing.

[0031] Specifically, the cold heading mechanism 6 is provided with a first cold heading mold, a second cold heading mold, and a third cold heading mold corresponding to the stepped groove 5. Each of the first, second, and third cold heading molds includes a first upper mold portion and a first lower mold portion. The bottom of each first upper mold portion includes a first fixed plate 61 mounted on the top machine base 22, a first punch 62 mounted on the first fixed plate 61 and capable of vertical telescopic movement, and a first limiting post 63 connected to the first fixed plate 61 and used to press against the top surface of the first upper mold portion. The first limiting post 63 is located around the first punch 62 to provide support to the first upper mold portion after it is supported on the top surface of the first lower mold portion, making it more stable. The bottom surface 321 of each first punch 62 is horizontal and is configured as a first pressing surface 621. The size of the first punch 62 is smaller than the inner wall size of the housing so that it can be inserted into the housing.

[0032] Each first lower die includes a first lower template 64 fixedly mounted on the bottom machine base 21, a first die pad 65 fixedly mounted on the top surface of the first lower template 64, and a first die 66 fixedly mounted on the top of the first die pad 65. The top surface of the first die 66 is horizontal to support the first limiting post 63. A first positioning groove 661 for the housing to pass through is recessed at the position of the first punch 62 on the top surface of the first die 66. A first pad 662 is provided in the first positioning groove 661. A first support surface 663 for supporting the bottom wall 11 of the housing is provided on the first top surface. A cold heading cavity for the first punch 62 and the housing to pass through vertically is formed between the first support surface 663 and the first positioning groove 661. The bottom wall 11 of the cold heading cavity is also the first support surface 663.

[0033] In one embodiment, no forming protrusion is provided on the first support surface 663 of the first cold heading mold, or the forming protrusion on the first cold heading mold is flush with the first support surface 663. This allows the horizontal first pressing surface 621, first support surface 663, and corresponding forming protrusion to flatten the punched bottom wall 11 of the housing and play a shaping role when the first punch 62 of the first cold heading mold moves downwards to press the first pressing surface 621 against the bottom wall 11 of the housing. This ensures the accuracy of the step groove 5 forming during processing. The first protrusion 671 is formed on the first support surface 663 of the second cold heading mold and is located at the center of the first support surface 663, protruding upwards from it. The first protrusion 671 is formed by protruding vertically upwards and has a vertical side surface and a horizontal top surface. A first clearance hole 672 is vertically formed at the center of the top surface of the first protrusion 671 to avoid the explosion-proof hole, reducing interference when the first protrusion 671 presses against the edge of the explosion-proof hole from the bottom surface 321 of the housing. Simultaneously, the pressure exerted between the first pressing surface 621, the first supporting surface 663, and the first protrusion 671 on the bottom wall 11 of the housing creates a first groove around the edge of the explosion-proof hole. The inner wall of the first groove is configured as a first groove surface, and the vertical cross-section of the first groove surface is stepped or L-shaped. The second protrusion 673 is formed on the first supporting surface 663 of the third cold-forging mold and is located at the center of the first supporting surface 663, protruding upwards from it. The second protrusion 673 is formed by protruding vertically upwards and has a vertical side surface and a horizontal top surface. The second protrusion 673 is configured as two layers, with one vertical side surface and one horizontal top surface forming one layer, and the two layers are distributed vertically. The second protrusion 673 of the bottom layer extends outward in the horizontal direction relative to the top layer, while the top layer narrows inward relative to the bottom layer, forming a two-tiered stepped structure with the size of the top layer being smaller than that of the bottom layer. It should be noted that the size of each step structure of the second protrusion 673 is larger than the size of the explosion-proof hole. The first protrusion 671 and the second protrusion 673 narrow sequentially in the radial direction, and their radial dimensions are larger than the size of the explosion-proof hole. A second clearance hole 674 is vertically formed on the top surface of the second protrusion 673 at its center position to avoid the explosion-proof hole. Simultaneously, the first pressing surface 621, the first supporting surface 663, and the second protrusion 673 press against the bottom wall 11 of the housing, pressing out a second groove segment around the edge of the explosion-proof hole. The inner wall of each step structure of the second groove segment is a second groove surface. The number of second groove surfaces depends on the configuration; in this embodiment, there are two second groove surfaces corresponding to the two-tiered stepped structure.

[0034] In use, the robotic arm places the shells with explosion-proof holes one by one into the cold-forging cavities of the first, second, and third cold-forging molds. The first punches 62 move downwards sequentially, pressing the first pressing surface 621 against the first supporting surface 663. Through compression, the bottom wall 11 of the shell is formed into first and second groove segments under the pressure of the first and second protrusions 671 and 673. The formed first and second groove segments and the explosion-proof holes are sequentially connected and gradually narrow along the thickness and radial direction of the bottom wall 11. This creates layered stepped grooves 5 at the edges of the explosion-proof holes, increasing the contact area between the inner wall of the explosion-proof hole and the explosion-proof valve, thus improving the bonding force.

[0035] Please see Figure 12 The trimming mechanism 7 includes a trimming die, which includes a fourth upper die mounted on a top machine base 22 and a fourth lower die mounted on a bottom machine base 21. The fourth upper die includes a fourth fixed plate 71 fixed on the top machine base 22, a fourth limiting post 72 fixed on the fourth fixed plate 71 and used to press against the top surface of the fourth lower die, and a fourth punch 73 located on the fourth fixed plate 71 and capable of vertical telescopic movement. The fourth punch 73 is used to penetrate into the housing and has an upper cutting edge at its bottom edge. The fourth lower die includes a fourth lower template 74 mounted on the bottom machine base 21, a fourth die pad 75 fixed on the fourth lower template 74, and a fourth ejector rod 76 disposed in the fourth die pad 75. A vertically penetrating slide rail is provided in the fourth lower template 74. The inner wall of the slide rail forms an asymmetrical and wavy rail surface 741. A protruding secondary rail surface 741 is formed on the outer wall of the fourth die pad 75 corresponding to the rail surface 741. A fourth positioning groove is vertically formed on the fourth die plate 75, and a fourth ejector rod 76 is movably inserted into the fourth positioning groove.

[0036] In use, the shell connecting part 13 is placed upwards on the fourth ejector pin 76. The fourth ejector pin 76 moves upwards, gradually fitting the shell onto the fourth punch 73 until the fourth ejector pin 76 presses the bottom wall 11 against the bottom surface 321 of the fourth punch 73; or the shell connecting part 13 is placed upwards on the fourth ejector pin 76, and the fourth punch 73 moves downwards until the bottom wall 11 presses against the fourth ejector pin 76, thus completing the shell positioning. Then, a press or other power equipment drives the entire fourth die plate 75 to move vertically. Through the guide surface 741 and the secondary guide surface 741, the fourth die moves back and forth vertically, gradually pressing the shell side wall 12 from all directions. The connection between the side wall 12 and the connecting part 13 is cut off by rotary cutting at the cutting edge, separating the excess side wall section 142 and the connecting section, thus forming the shell. The specific principle is the same as that of a rotary cutting die, and will not be described in detail here.

[0037] Please see Figure 13 and Figure 14The secondary punching mechanism 84 includes a secondary punching die, which includes a fifth upper die mounted on a top machine base 22 and a fifth lower die mounted on a bottom machine base 21. The fifth upper die includes a fifth fixed plate 81 connected to the top machine base 22 and a fifth punch 82 mounted on the fifth fixed plate 81. The fifth punch 82 can move vertically relative to the fifth fixed plate 81, and the bottom of the fifth fixed plate 81 also has a fifth limiting post 83 for supporting the fifth lower die. The fifth punch 82 is installed between the fifth limiting posts 83. The fifth punch 82 has a fifth pressing surface 822 for pressing against the bottom wall 11 of the housing and a second punching post 821 located inside the fifth pressing surface 822 and corresponding to the position of the explosion-proof hole on the bottom wall 11. The horizontal cross-sectional shape and size of the second punching post 821 are consistent with the shape and size of the explosion-proof hole and protrude downward from the fifth pressing surface 822. The second punching post 821 can move vertically independently relative to the fifth pressing surface 822, so that after the fifth pressing surface 822 is pressed against the bottom wall 11 of the housing, the second punching post 821 quickly punches out an explosion-proof hole from the bottom wall 11; or the second punching post 821 can be fixed relative to the fifth pressing surface 822, so that the fifth pressing surface 822 and the second punching post 821 always move together.

[0038] The fifth lower die section includes a fifth lower template 84 fixedly mounted on the bottom machine base 21, a fifth die pad 85 fixedly mounted on the top surface of the fifth lower template 84, and a fifth die 86 fixedly mounted on the top of the fifth die pad 85. The top surface of the fifth die 86 is horizontal and serves to support the fifth limiting post 83. A fifth positioning groove 87 is recessed on the top surface of the fifth die 86, and a fifth pad 88 is provided inside the fifth positioning groove 87. The top surface of the fifth pad 88 is horizontal to support the bottom wall 11 of the housing. A third protrusion 881 with the same shape as the stepped groove 5 is protruding on the top surface of the fifth pad 88 to support the stepped groove 5 when the housing is inserted therein, ensuring the shape and structure of the stepped groove 5. A second clearance hole 882 is provided on the top surface of the fifth pad 88 at the position corresponding to the second punch post 821. The second punch post 821 is clearance hole 882 formed during punching to avoid the second punch post 821. When the fifth punch 82 penetrates the fifth positioning groove 87, a fifth forming cavity is formed between the fifth punch 82 and the inner wall of the fifth positioning groove 87, which is consistent with and adapted to the contour of the inner and outer walls of the housing. Preferably, the fifth lower die also has a push rod located below the fifth pad 88, which is used to push the fifth pad 88 upward after punching to facilitate the robot arm to grasp the housing with the explosion-proof hole processed.

[0039] In use, the open side of the housing faces the fifth punch 82 and the bottom wall 11 side is inserted into the fifth positioning groove 87 to position the housing. Then the fifth punch 82 moves downward and gradually penetrates into the housing until the secondary punching and reinforcement of the explosion-proof hole is completed. The explosion-proof hole is then reprocessed to form a standard explosion-proof hole structure.

[0040] Please see Figure 15 and Figure 16 The forming mechanism 9 includes a forming mold, which includes a sixth upper mold portion mounted on the top machine base 22 and a sixth lower mold portion mounted on the bottom machine base 21. The sixth upper mold portion includes a sixth fixing plate 91 fixed on the top machine base 22, a sixth limiting post 92 fixed on the sixth fixing plate 91 and used to press against the top surface of the sixth lower mold portion, and a sixth punch 93 located on the sixth fixing plate 91 and capable of vertical telescopic movement.

[0041] The sixth lower mold section includes a sixth lower template 94 fixedly mounted on the bottom machine base 21, a sixth die pad 95 fixedly mounted on the top surface of the sixth lower template 94, and a sixth die 96 fixedly mounted on the top of the sixth die pad 95. The top surface of the sixth die 96 is horizontal and is used to support the sixth limiting post 92. A sixth positioning groove 961 is recessed on the top surface of the sixth die 96. A sixth pad 962 is provided in the sixth positioning groove 961. The top surface of the sixth pad 962 is horizontal to support the bottom wall 11 of the housing. A fourth protrusion 963, which is consistent with the shape of the stepped groove 5 and the explosion-proof hole, is protruding on the top surface of the sixth pad 962. This protrusion is used to support the stepped groove 5 and the explosion-proof hole when the housing is inserted into it, ensuring the shape and structure of the stepped groove 5 and the explosion-proof hole, and completing the shaping of the explosion-proof hole and the stepped groove 5. When the sixth punch 93 penetrates into the sixth positioning groove 961, a sixth forming cavity is formed between the sixth punch 93 and the inner wall of the sixth positioning groove 961, which is consistent with and adapted to the contour of the inner and outer walls of the housing. Preferably, the sixth lower die also has a push rod located below the sixth pad 962, which is used to push the sixth pad 962 upward after punching is completed so that the robot arm can grasp the housing with the explosion-proof hole processed.

[0042] In use, the open side of the housing faces the sixth punch 93 and the bottom wall 11 side is inserted into the sixth positioning groove 961 to position the housing. Then the sixth punch 93 moves downward and gradually penetrates into the housing. By squeezing the housing, explosion-proof hole and stepped groove 5, the explosion-proof hole and stepped groove 5 are precisely formed, and the housing is formed.

[0043] It should be noted that each pad is equipped with an anti-detachment block and an anti-detachment buckle is installed in the corresponding positioning groove. After the push rod pushes the pad to move upward a certain distance, the anti-detachment block abuts against the anti-detachment buckle to prevent the corresponding pad from detaching from the corresponding positioning groove.

[0044] The working method of one embodiment of the shell forming device of this utility model is as follows: Stacked sheet materials 1 are moved individually and inspected. Qualified sheet materials 1 are sequentially conveyed and stretched. Stretching forming: After stretching, sheet materials 1 form a hollow shell and a connecting part 13 connected to the shell, thus forming a first forming blank. Punching processing: Explosion-proof holes are machined on the shell. Cold heading processing: An auxiliary structure is machined at the edge of the explosion-proof holes to facilitate their connection with explosion-proof valves. Product forming: The connecting part 13 is disconnected and finely shaped to form the shell. Product forming includes edge trimming: Excess sidewall sections 142 and connecting sections are disconnected to form a shell blank. Secondary punching processing: The explosion-proof holes on the shell blank are re-processed to form a standard explosion-proof hole structure. Shaping processing: A sixth forming cavity is formed, consistent with the contours of the explosion-proof holes and stepped grooves 5. The shell blank is then precisely formed by extruding the shell blank, completing the shell forming process.

[0045] Compared with the prior art, the shell forming device of this utility model adopts a transition stretching method to gradually stretch the material sheet 1 into the shell, thereby improving the product yield. The cold heading mechanism 6 forms a stepped groove 5 at the edge of the explosion-proof hole, so as to make the installation of the explosion-proof valve more stable and reliable and improve the safety of the shell.

Claims

1. A shell forming apparatus for processing a shell, the shell comprising a bottom wall and side walls, characterized in that: The device includes, in sequence, a stretching mechanism for stretching a sheet into a shell and a connecting part, a punching mechanism for machining explosion-proof holes on the stretched shell, and a cold forging mechanism for machining auxiliary structures on the edges of the explosion-proof holes. The auxiliary structures facilitate integration with explosion-proof valves.

2. The shell forming apparatus as described in claim 1, characterized in that: The auxiliary structure includes a stepped groove that extends from the edge of the explosion-proof hole along the thickness direction of the bottom wall of the shell from the outside of the shell to the inside of the shell and gradually narrows radially toward the center to form a stepped shape; the cold forging mechanism corresponds to the stepped groove to form a cold forging structure and a pressing part for pressing the bottom wall onto the cold forging structure so that the stepped groove is formed on the bottom wall of the shell.

3. The shell forming apparatus as described in claim 2, characterized in that: The cold-forging structure has a first support surface for supporting the bottom wall of the shell and a forming protrusion protruding from the first support surface and consistent with the contour of the stepped groove. The pressing part has a first pressing surface adapted to the inward side of the bottom wall of the shell.

4. The shell forming apparatus as described in claim 3, characterized in that: The stepped groove includes at least a first groove segment, the first groove segment forming a first groove surface at the explosion-proof hole, and the molded protrusion includes a first protrusion adapted to the first groove surface. The stepped groove also includes a second groove segment. The first groove segment, the second groove segment, and the explosion-proof hole are connected sequentially along the thickness direction of the bottom wall and gradually narrow. The second groove segment makes at least one second groove surface formed at the explosion-proof hole. The formed protrusion also includes a second protrusion adapted to the second groove surface. The cold forging mechanism is provided with a first cold forging mold, a second cold forging mold, and a third cold forging mold corresponding to the stepped groove. A first support surface is formed on the first cold forging mold, the second cold forging mold, and the third cold forging mold. A first protrusion is formed on the first support surface of the second cold forging mold, and a second protrusion is formed on the first support surface of the third cold forging mold. A first pressing surface is provided on the first cold forging mold, the second cold forging mold, and the third cold forging mold.

5. The shell forming apparatus as described in claim 4, characterized in that: The first cold heading mold, the second cold heading mold, and the third cold heading mold all include a first upper mold part and a first lower mold part; The bottom of the first upper die has a first punch for vertical telescopic movement and a first limiting post for pressing against the top surface of the first upper die, and the bottom surface of the first punch is configured as a first pressing surface. The top of the first lower die portion is recessed with a cold heading cavity for the first punch to pass through vertically therein, and the bottom wall of the cold heading cavity is configured as the first support surface.

6. The shell forming apparatus as described in claim 1, characterized in that: The stretching mechanism has a stretching cavity adapted to the shape of the outer wall of the housing and a forming part for extruding the sheet into the stretching cavity and pressing the sheet to form the inner wall of the housing. The stretching cavities are configured in multiple ways and distributed from shallow to deep. The forming part is configured in multiple ways to correspond to each stretching cavity and cooperates with each stretching cavity to stretch the material sheet so that the shell and the connecting part are gradually stretched and formed.

7. The shell forming apparatus as described in claim 6, characterized in that: Each of the stretching cavities is connected to a corresponding forming part to form a second forming cavity for extruding and stretching the sheet material; each of the second forming cavities includes a bottom wall cavity for fitting to the bottom wall of the housing, a transition cavity, a side wall cavity for fitting to the side wall of the housing, and a connecting cavity for fitting to the connecting part. The width of each bottom wall cavity decreases sequentially until it matches the outline of the bottom wall of the shell. The width of each transition cavity decreases sequentially until it disappears and is inclined relative to the bottom wall cavity. The width of each side wall cavity increases sequentially until it matches the outline of the side wall of the shell and is perpendicular to the bottom wall cavity. The material connecting cavity gradually tilts from horizontal and its width decreases sequentially until it matches the outline of the material connecting part.

8. The shell forming apparatus as described in claim 7, characterized in that: The stretching mechanism includes multiple stretching dies, and multiple stretching cavities and forming parts are sequentially formed on each stretching die; each stretching die includes a second upper die part and a second lower die part. The second upper die is configured as the forming part and has a second punch for vertical telescopic movement and an inner extrusion ring for extruding to form a connecting part. The second punch has an inner forming surface corresponding to the inner wall of the housing. The second lower die portion has a recessed stretching cavity at its top for the second punch to pass through vertically therein, and the inner forming surface and the stretching cavity surround to form the second forming cavity.

9. The shell forming apparatus as described in claim 1, characterized in that: It also includes a trimming mechanism for removing the connecting material from the shell on which the auxiliary structure is machined, a secondary punching mechanism for reprocessing the explosion-proof holes after the cold heading mechanism has been machined, and a shaping mechanism for modifying the shape of the shell.

10. The shell forming apparatus as described in claim 1, characterized in that: It also includes a storage section for stacking and storing sheet materials, a conveying device for conveying sheet materials to a stretching mechanism, a transfer device for sequentially transferring sheet materials from the storage section to the conveying device, and a detection device for detecting each sheet material passing through the conveying device.

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