Progressive aluminum alloy square shell forming die and aluminum alloy square shell

Abstract

This invention discloses a progressive aluminum alloy square shell forming mold and an aluminum alloy square shell, belonging to the field of aluminum alloy processing and forming technology. The mold includes a lower mold assembly, an upper mold assembly, a material discharge assembly, and a feeding preheating module integrated into the inlet. The lower and upper molds are respectively equipped with six stations: punching, blanking, pre-bending, secondary bending, side punching / end bending, and shaping and blanking. The feeding preheating module includes a guide cleaning roller assembly, a drive pressing roller assembly, a material distribution and indentation mechanism, and a preheating plate with air vents. The indentation seat is equipped with an air inlet pipe connected to the air vents for supplying hot air to the strip and each station, maintaining the temperature stability of the aluminum alloy strip during continuous stamping. This invention achieves integrated forming of high-strength aluminum alloy square shells from coil to finished product through a multi-station progressive structure and preheating temperature control, effectively suppressing springback and cracking, and achieving high production efficiency. The invention also discloses an aluminum alloy square shell formed by this mold, featuring an integrated U-shaped end mounting lug and mounting hole.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy processing and forming technology, and more specifically, to a progressive forming die for the continuous production of high-strength aluminum alloy square shells, and the aluminum alloy square shells formed by the die. Background Technology

[0002] With the rapid development of new energy vehicles, energy storage equipment, and lightweight electronic products, the performance requirements for structural components such as battery casings are increasing. Aluminum alloys, due to their high specific strength, good thermal conductivity, and corrosion resistance, have become the mainstream material for manufacturing battery slabs. However, high-strength aluminum alloys (such as 6061 and 7075 series) have low plasticity and high springback at room temperature, making them prone to cracking and dimensional deviations in traditional stamping processes.

[0003] In existing technologies, the production of aluminum alloy square shells mostly adopts a step-by-step forming process of stretching, trimming, and bending, or uses a single-station compound mold. These methods have the following shortcomings: 1. The processes are scattered, requiring multiple sets of molds and multiple feeding and positioning operations, resulting in low efficiency and high cost; 2. Large cumulative errors from multiple positioning attempts affect the consistency of housing dimensions and the positional accuracy of the mounting ears; 3. When aluminum alloy is bent in a cold state, micro-cracks or springback may occur in the material, resulting in angle deviation. Subsequent shaping or heat treatment processes are required. 4. Lack of active control over strip temperature, especially in continuous stamping, leads to uneven heating due to friction between the strip and the die, further deteriorating molding stability.

[0004] Therefore, there is an urgent need to develop a mold structure that can achieve high-precision and high-efficiency continuous forming of aluminum alloy square shells and effectively control the risk of material springback and cracking. Summary of the Invention

[0005] To solve the above technical problems.

[0006] This application provides a progressive aluminum alloy square shell forming mold that integrates preheating, multi-station progressive forming and automatic unloading, as well as an aluminum alloy square shell with a reasonable structure that is integrally formed by the mold.

[0007] It includes: a lower mold assembly, an upper mold assembly, a material discharge assembly, and a material feeding and preheating module for feeding and preheating high-strength aluminum alloy strip. The lower mold assembly and the upper mold assembly are aligned and close together. The material discharge assembly and the material feeding and preheating module are integrated into the mold as a whole. The lower die assembly includes a lower die base, a lower die pad, a die fixing plate, a multi-station die forming block, a guide post assembly, and support feet; the multi-station die forming block is divided into punching die, blanking die, pre-bending die, secondary bending die, side punching / end bending die, and shaping and blanking die according to the strip feeding direction. The upper die assembly includes an upper die base, an upper die pad, a punch fixing plate, a stripper plate, a guide sleeve assembly, a multi-station punch forming block, and an elastic stripper component; the multi-station punch forming block is divided into punching station punch, blanking station punch, pre-bending station punch, secondary bending station punch, side punching / end bending station punch, and shaping and blanking station punch according to the strip feeding direction; the multi-station punch forming block corresponds one-to-one with the lower die multi-station concave die forming block. The feeding and preheating module includes a guide cleaning roller group, a drive pressing roller group, a material distribution and indentation mechanism, and a preheating plate. These components are sequentially installed at the inlet of the feeding and discharging assembly. The guide cleaning roller group includes two cleaning rollers for cleaning the upper and lower surfaces of the aluminum alloy strip, and a guide roller for guiding and constraining the strip. The drive pressing roller group includes a drive roller and a lower pressing roller. The drive roller, in conjunction with the lower pressing roller, achieves the pressing and conveying of the aluminum alloy strip, providing conveying power and ensuring the strip is properly compressed and conveyed. The strip is pressed and shaped. The material sizing and creasing mechanism includes a creasing knife and a creasing seat. The creasing knife and creasing seat work together to press out the material break lines between adjacent material areas on the aluminum alloy strip, which facilitates the final product cutting. A preheating plate is installed at the inlet to heat the aluminum alloy strip. Multiple air vents are opened in the preheating plate. An air inlet pipe is installed on the creasing seat and connected to the air vents on the preheating plate. The air inlet pipe works with the preheating plate to deliver hot air to the strip and subsequent work stations to prevent the strip from cooling and keep the temperature of the strip stable within a certain range. The discharge assembly includes a discharge port, a discharge chute, and a guiding and positioning unit, enabling continuous feeding of strip materials and automatic discharge of finished products.

[0008] Furthermore, the lower mold base is a rigid bearing plate, with the bottom fixed by support feet. The lower mold pad is stacked on top of the lower mold base, and the cavity mold fixing plate is fixed on top of the lower mold pad for installing multi-station cavity mold forming blocks. The guide post assembly is installed at the four corners of the lower mold base and cooperates with the upper mold guide sleeve assembly to ensure mold closing accuracy.

[0009] Furthermore, the punch and die of the punching station cooperate to punch process holes, positioning guide holes, and square shell side wall holes, as well as mounting holes for end mounting ears on the square shell, on the aluminum alloy strip using the corresponding punch head on the punch.

[0010] Furthermore, the punch and die of the blanking station cooperate to punch out the outer contour of the aluminum alloy square shell using the square punch and U-shaped punch on the punch, while retaining the material strip connecting carrier to achieve continuous feeding.

[0011] Furthermore, the pre-bending station punch and the pre-bending station die work together to use the indentation heads on the pre-bending station punch and the pre-bending station die to stamp out the bending lines at the bottom of the square shell body, the bending lines at the connection between the end mounting ears and the square shell body, and the side wall bending lines of the end mounting ears, respectively.

[0012] Furthermore, the punch and die of the secondary bending station cooperate to bend the U-shaped sidewall of the end mounting ear upwards by using the upper pressure head on the punch and the lower bending seat of the die along the bending line of the sidewall of the end mounting ear.

[0013] Furthermore, the side punch / end bending station punch and the side punch / end bending station die work together to bend the end mounting ear downwards along the bending line at the connection between the end mounting ear and the square shell body, and to bend the side wall connected to the end mounting ear upwards along two bending lines at the bottom of the square shell body.

[0014] Furthermore, the forming and blanking station punch and the forming and blanking station die work together to cut the finished product and carrier strip along the cutting line using the cutting blade installed on the forming and blanking station punch. Then, the forming pressure head bends the other two side walls of the square shell body upward along the other two bending lines at the bottom of the shell body to complete the forming of the aluminum alloy square shell.

[0015] Furthermore, the stripper plate is connected to the punch fixing plate through an elastic stripper component, and the elastic stripper component is connected to the stripper plate through a spring structure to provide pressing force and stripping force to prevent the strip from springing back and shifting.

[0016] Furthermore, the inlet and outlet of the feeding and discharging assembly are located at both ends of the lower die base, and the guiding and positioning unit includes a guiding hole and a guiding pin to ensure the accuracy of the feeding step distance.

[0017] An aluminum alloy square shell, formed by the progressive aluminum alloy square shell forming mold described in any one of the above, includes: a square shell body, end mounting ears, and mounting holes; the end mounting ears are located on both sides of the upper end of the square shell body and form a symmetrical elongated U-shaped structure, which is integrally formed by bending aluminum alloy sheet twice; the end mounting ears are U-shaped groove structures with bends at both ends of the square shell body, and each mounting ear is provided with 2 mounting holes. Beneficial effects

[0018] Compared with the prior art, the present invention has the following significant advantages: Integrated preheating and temperature control: By setting a preheating plate at the feed inlet and an air inlet pipe that delivers hot air to each station, the aluminum alloy strip reaches a predetermined temperature (e.g., 150-250℃) before entering the forming zone, effectively reducing the material's yield strength, increasing plasticity, and reducing the risk of cold bending cracks; at the same time, continuous hot air prevents the strip from cooling in the long-distance progressive die, ensuring stable temperature throughout the process, thereby significantly suppressing springback and improving dimensional consistency.

[0019] Multi-station progressive forming: Six stations, including punching, blanking, pre-bending, secondary bending, side punching / end bending, and shaping and blanking, are integrated into one mold, realizing fully automated continuous production from coil to finished product. There is no need for intermediate transfer and secondary positioning, which increases production efficiency by more than 3 times. Moreover, the pitch accuracy is guaranteed by the guide pin, resulting in excellent product consistency.

[0020] The two-bending process for U-shaped mounting ears involves first pre-bending the U-shaped sidewall of the mounting ear upwards at a secondary bending station, and then bending the entire mounting ear downwards at a side punch / end bending station. This avoids root cracking caused by a single large-angle bend and is particularly suitable for forming complex shapes of high-strength aluminum alloys.

[0021] Pre-indentation assisted bending: Multiple bending lines are precisely pressed at the pre-bending station to guide the material to bend along the predetermined lines during subsequent bending, reducing friction and stress concentration, ensuring accurate bending angles, and the lines also act as stress relief grooves.

[0022] Material break line + shaping and blanking: The material break line is pressed out by the material dividing and pressing mechanism during the feeding stage, and finally cut by the material break knife at the shaping and blanking station. The cut is neat and burr-free, and does not damage the cutting edge of the mold.

[0023] Product structure optimization: The formed aluminum alloy square shell has an integrated U-shaped end mounting lug, which is strong and accurately positioned. The mounting holes are completed simultaneously at the punching station, eliminating the need for subsequent machining. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the three-dimensional structure of the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the three-dimensional structure of the present invention. Figure 2 ; Figure 3 This is a side view of the present invention; Figure 4 This is a three-dimensional structural diagram of the lower mold assembly of the present invention; Figure 5 This is a three-dimensional structural diagram of the upper mold assembly of the present invention; Figure 6 This is a three-dimensional structural diagram of the feeding and preheating module of the present invention. Figure 1 ; Figure 7 This is a three-dimensional structural diagram of the feeding and preheating module of the present invention. Figure 2 ; Figure 8 This is a three-dimensional structural cross-sectional view of the upper mold assembly of the present invention; Figure 9 This is a diagram showing the finished aluminum alloy square shell and its layout according to the present invention.

[0025] The numbers in the diagram are: 1-lower mold assembly; 2-upper mold assembly; 3-feeding preheating module; 4-discharge assembly; 11-Lower mold base; 12-Lower mold pad; 13-Die fixing plate; 14-Multi-station die forming block; 15-Guide pillar assembly; 16-Support foot; 141-Punching station die; 142-Blanking station die; 143-Pre-bending station die; 144-Secondary bending station die; 145-Side punching / end bending station die; 146-Shaping and blanking station die; 21-Upper mold base; 22-Upper mold pad; 23-Punch fixing plate; 24-Ejector plate; 25-Guide sleeve assembly; 26-Multi-station punch forming block; 27-Elastic ejector component; 261-Punching station punch; 262-Blanking station punch; 263-Pre-bending station punch; 264-Secondary bending station punch; 265-Side punch / end bending station punch; 266-Shaping and blanking station punch; 267-Cutting knife; 268-Shaping pressure head; 31-Guide and cleaning roller assembly; 311-Cleaning roller; 312-Guide roller; 32-Drive and pressing roller assembly; 321-Drive roller; 322-Lower pressing roller; 33-Distribution and indentation mechanism; 331-Indentation knife; 332-Indentation seat; 333-Air inlet pipe head; 34-Preheating plate; 341-Air outlet; 41-Discharge port; 42-Discharge chute; 43-Guide pin; 51-Square shell body; 52-End mounting ears; 53-Mounting holes; 54-Heat dissipation holes. Detailed Implementation

[0026] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Example

[0028] This embodiment provides a progressive forming die for producing aluminum alloy square shells for new energy vehicle power batteries, and the aluminum alloy square shells produced by the die. The aluminum alloy material is 6061-T6 state aluminum alloy strip with a thickness of 1.2mm and a width of 180mm.

[0029] Mold structure: like Figures 1 to 9 As shown, the mold includes a lower mold assembly 1, an upper mold assembly 2, a feeding and preheating module 3, and a discharge assembly 4. The lower mold assembly 1 and the upper mold assembly 2 are guided to close the mold by a guide post assembly 15 and a guide sleeve assembly 25.

[0030] Lower die assembly 1: The lower die base 11 is made of 45 steel quenched plate, 50mm thick, and is fixed to the press worktable by four support feet 16 at the bottom. The lower die pad 12 and the die fixing plate 13 are stacked in sequence and locked with locating pins and bolts. The multi-station die forming blocks 14 are arranged from left to right according to the feeding direction as follows: punching station die 141, blanking station die 142, pre-bending station die 143, secondary bending station die 144, side punching / end bending station die 145, and shaping and blanking station die 146. All dies are made of Cr12MoV steel with a heat treatment hardness of HRC58-62.

[0031] Upper die assembly 2: Upper die base 21 is connected to the press slide via die shank. Upper die pad 22 and punch fixing plate 23 are fixed in sequence. Multi-station punch forming block 26 corresponds one-to-one with the lower die station. Stripper plate 24 is connected to punch fixing plate 23 via four elastic stripper elements 27 and nitrogen springs. When the die is closed, the stripper plate first contacts the strip to provide pressure force, and when the die is opened, it pushes the strip down.

[0032] As shown in the figure, the feeding and preheating module 3 is installed on the feeding side of the mold. After the aluminum alloy coil is unrolled, it first enters the guide and cleaning roller group 31. The upper and lower cleaning rollers 311 are covered with wear-resistant felt and rotate to remove oil and aluminum chips from the surface of the strip; the guide roller 312 ensures that the strip enters straight. Then it enters the drive and pressing roller group 32: the drive roller 321 is driven by a servo motor, and the lower pressing roller 322 provides pressing force through a cylinder, with a conveying step distance accuracy of ±0.05mm. The indentation knife 331 of the material separating and indenting mechanism 33 has a diamond-shaped cutting edge, which indents a 0.3mm deep cutting line on both sides of the strip, with a spacing equal to the unfolded length of a square shell. The preheating plate 34 is a cast aluminum heating plate with built-in electric heating tubes, and the surface temperature is controlled at 200±10℃. The preheating plate 34 has multiple air vents 341, which are connected to the air inlet pipe head 333 on the indentation seat 332 via flexible hoses. Hot air is blown onto the surface of the material strip and each work station area at the same time. The actual measured temperature of the material strip at each work station is maintained at 180-210℃.

[0033] Discharge assembly 4: The discharge port 41 is located at the end of the mold, and the finished product slides into the collection box through the discharge chute 42. The guide pin 43 is installed on the unloading plate 24 and cooperates with the guide hole punched out by the punching station. It is inserted for correction during each feeding step.

[0034] Molding process: The stamping press has a stroke rate of 40 times per minute and a feeding step distance of 150 mm.

[0035] Step 1: Punching Station. The punch 261 at the punching station is equipped with a Ø6mm punch mounting hole, a Ø4mm punch guide hole, and 2×10mm flat hole punch sidewall heat dissipation holes. Two mounting holes 53 are punched on each of the mounting ears 52 on both sides of the square shell body 51, for a total of 4 holes. At the same time, guide holes are punched.

[0036] Step 2: Blanking Station. The blanking station punch 262 is a combination type. The square punch punches out the square shell body 51 with an unfolded shape of 110×80mm rectangle, and the U-shaped punch punches out the U-shaped unfolded outline with end mounting ears. A 2mm wide connecting carrier is retained on both sides of the strip so that the workpiece is still attached to the strip.

[0037] Step 3: Pre-bending station. The pre-bending station punch 263 has three indentation lines: the first is located along the long side of the bottom center of the square shell body 51, the second is located at the connection between the end mounting ear and the body, and the third is located at the root of the mounting ear's side wall. The indentation depth is 0.2mm, the width is 0.5mm, and the radius (R) is 0.1mm.

[0038] Step 4: Secondary bending station. At the secondary bending station, the upper pressure head on the punch 264 bends the U-shaped sidewall of the mounting ear 52 upwards by 90° along the third groove line, forming the sidewall of the U-shaped groove. The lower bending seat of the die is equipped with a clearance groove to avoid interference.

[0039] Step 5: Side Punch / End Bending Station. The punch 265 at the side punch / end bending station is equipped with a wedge mechanism. First, the horizontal side punch finally punches through the heat dissipation holes 54 on the side wall of the square shell body 51. Then, the upper die moves downward, driving the wedge to drive the vertical bending block to bend the entire end mounting ear 52, which already has a U-shaped side wall, downward by 90° along the second groove line, making it perpendicular to the end face of the square shell body 51. At the same time, along two short edge groove lines at the bottom of the square shell body 51, the two side walls connecting the body and the mounting ear 52 are pre-bent upward.

[0040] Step 6: Shaping and Blanking Station. The shaping and blanking punch 266 is equipped with a cutting blade 267 and a shaping pressure head 268. The cutting blade cuts the connecting carrier along the cutting line created in Step 1, separating the finished product. The shaping pressure head 268 bends the remaining two side walls of the square shell body 51 upwards by 90° along the remaining two long side lines, while simultaneously pressing the two previously pre-bent side walls further to 90°, and performing a 0.2mm over-bending shaping on all bends to compensate for springback. The final result is as follows... Figure 9 The aluminum alloy square shell shown.

[0041] Product after molding: The aluminum alloy square shell includes a main body 51 measuring 110×80×45mm with a wall thickness of 1.2mm, and U-shaped groove structures for the end mounting ears 52 located on the upper sides at both ends. The grooves are 12mm wide and 8mm deep, and each mounting ear has two Ø6mm mounting holes 53. The verticality of the four side walls of the main body 51 is ≤0.2mm, the positional accuracy of the mounting ears 52 is ≤0.15mm, and there are no cracks visible to the naked eye.

[0042] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A progressive aluminum alloy square shell forming mold, characterized in that, include: The lower mold assembly (1), the upper mold assembly (2), the feeding and discharging assembly (4), and the feeding and preheating module (3) for feeding and preheating high-strength aluminum alloy strip are provided. The lower mold assembly (1) and the upper mold assembly (2) are aligned and closed. The feeding and discharging assembly (4) and the feeding and preheating module (3) are integrated into the mold as a whole. The feeding preheating module (3) includes a guide cleaning roller group (31), a drive pressing roller group (32), a material distribution and indentation mechanism (33), and a preheating plate (34). The guide cleaning roller group (31), the drive pressing roller group (32), the material distribution and indentation mechanism (33), and the preheating plate (34) are installed sequentially at the inlet of the feeding and discharging assembly (4). The guide cleaning roller group (31) includes two cleaning rollers (311) for cleaning the upper and lower surfaces of the aluminum alloy strip and a guide roller (312) for guiding and constraining the strip. The drive pressing roller group (32) includes a drive roller (321) and a lower pressing roller (322). The drive roller (321) cooperates with the lower pressing roller (322) to realize the aluminum The pressing and conveying of the alloy strip provides conveying power to the strip and presses and shapes it. The material sorting and indentation mechanism (33) includes an indentation knife (331) and an indentation seat (332). The indentation knife (331) and the indentation seat (332) work together to press out the material break line between adjacent material areas on the aluminum alloy strip. The preheating plate (34) is installed at the inlet to heat the aluminum alloy strip. Multiple air vents (341) are opened in the preheating plate (34). An air inlet pipe head (333) connected to the air vents (341) on the preheating plate (34) is installed on the indentation seat (332). The air inlet pipe head (333) works with the preheating plate (34) to convey hot air to the strip and subsequent work stations. The feeding and discharging assembly (4) includes a discharge port (41), a discharge chute (42), and a guiding and positioning unit, which realizes continuous feeding of strip materials and automatic discharge of finished products.

2. The progressive aluminum alloy square shell forming mold according to claim 1, characterized in that, The lower mold assembly (1) includes a lower mold base (11), a lower mold pad (12), a die fixing plate (13), a multi-station die forming block (14), a guide post assembly (15), and support feet (16). The lower mold base (11) is a rigid bearing plate, and its bottom is fixed by the support feet (16). The lower mold pad (12) is stacked on top of the lower mold base (11), and the die fixing plate (13) is fixed on top of the lower mold pad (12) for installing the multi-station die. The forming block (14) is installed at the four corners of the lower die base (11) and cooperates with the upper die guide sleeve assembly (25). The multi-station die forming block (14) is divided into punching station die (141), blanking station die (142), pre-bending station die (143), secondary bending station die (144), side punching / end bending station die (145), and shaping and blanking station die (146) according to the strip feeding direction.

3. The progressive aluminum alloy square shell forming mold according to claim 1, characterized in that, The upper die assembly (2) includes an upper die base (21), an upper die pad (22), a punch fixing plate (23), a stripper plate (24), a guide sleeve assembly (25), a multi-station punch forming block (26), and an elastic stripper (27). The multi-station punch forming block (26) is divided into punching station punch (261), blanking station punch (262), pre-bending station punch (263), secondary bending station punch (264), side punching / end bending station punch (265), and shaping and blanking station punch (266) according to the strip feeding direction. The multi-station punch forming block (26) corresponds one-to-one with the lower die multi-station concave die forming block (14).

4. The progressive aluminum alloy square shell forming mold according to claim 3, characterized in that, The punching station punch (261) and the punching station die (141) work together to punch process holes, positioning guide holes and square shell side wall holes, as well as mounting holes for end mounting ears on the square shell, on the aluminum alloy strip using the corresponding punching head on the punching station punch (261).

5. The progressive aluminum alloy square shell forming mold according to claim 1, characterized in that, The punch (262) and die (142) of the punching station cooperate to punch out the outer contour of the aluminum alloy square shell by using the square punch and U-shaped punch on the punch (262) respectively, while retaining the material strip connecting carrier.

6. The progressive aluminum alloy square shell forming mold according to claim 1, characterized in that, The pre-bending station punch (263) and the pre-bending station die (143) work together to use the indentation heads on the pre-bending station punch (263) and the pre-bending station die (143) to stamp out the bending lines at the bottom of the square shell body, the bending lines at the connection between the end mounting ears and the square shell body, and the side wall bending lines of the end mounting ears.

7. The progressive aluminum alloy square shell forming mold according to claim 5, characterized in that, The secondary bending station punch (264) and the secondary bending station die (144) work together to bend the U-shaped sidewall of the end mounting ear upward along the bending line of the sidewall of the end mounting ear by using the upper pressure head on the secondary bending station punch (264) and the lower bending seat of the secondary bending station die (144).

8. The progressive aluminum alloy square shell forming mold according to claim 6, characterized in that, The side punch / end bending station punch (265) and the side punch / end bending station die (145) cooperate to respectively bend the end mounting ear downward along the bending line at the connection between the end mounting ear and the square shell body, and bend the side wall connected to the end mounting ear along two bending lines at the bottom of the square shell body.

9. The progressive aluminum alloy square shell forming mold according to claim 7, characterized in that, The forming blanking station punch (266) and the forming blanking station die (146) work together to cut the finished product and carrier strip along the blanking line using the cutting knife (267) installed on the forming blanking station punch (266). The forming pressure head (268) bends the other two side walls of the square shell body upward along the other two bending lines at the bottom of the shell body to complete the forming of the aluminum alloy square shell.

10. An aluminum alloy square shell, characterized in that, The aluminum alloy square shell is formed by the progressive aluminum alloy square shell forming mold according to any one of claims 1 to 9, and includes: a square shell body (51), end mounting ears (52), and mounting holes (53). The end mounting ears (52) are located on both sides of the upper end of the square shell body (51) and form a symmetrical long strip U-shaped structure, which is integrally formed by bending aluminum alloy sheet twice; The end mounting ears (52) are U-shaped groove structures with bends at both ends of the square shell body (51). Each mounting ear (52) is provided with two mounting holes (53). The square shell body (51) is a rectangular frame with four side walls formed by bending and no cracks at the bending corners. The mounting holes (53) are round holes or waist-shaped holes for fixed connection with external equipment.

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