A method for manufacturing a one-mold two-piece integrated die-cast front cabin

Abstract

The application discloses a preparation method of a one-mold two-piece integrated die-casting front cabin, and relates to the technical field of automobiles, and comprises the following steps: injecting molten aluminum alloy into a one-mold two-cavity die-casting cavity which is arranged in a central symmetry, and die-casting two symmetrically distributed integrated front cabin blanks; cutting off the pouring system and the overflow groove of the integrated front cabin blank, cleaning burrs and flash, and separating into two independent front cabins; wherein the pouring system of the cavity is designed in a central symmetry. Through the central symmetry arrangement of the mold cavity and the central symmetry design of the pouring system, the flow paths of the metal liquid are consistent, the temperature field and the pressure field are uniformly distributed when the metal liquid fills the two cavities, so that the internal quality and the mechanical properties of the two castings are consistent.

Description

Technical Field

[0001] This application relates to the field of automotive technology, and in particular to a method for preparing a die-cast front engine compartment in a single mold with two integrated parts. Background Technology

[0002] Traditional automotive engine compartments typically employ sheet metal stamping and welding structures, usually composed of dozens of sheet metal parts connected by welds, bolts, and structural adhesives. For example, a front engine compartment structure may require 38 parts welded together, containing as many as 469 weld points, and utilizing numerous standard parts (such as 84 M8 rivet nuts) and over 9 meters of spot welding sealant, resulting in an overall weight of 43 kg. This manufacturing method is complex, has low assembly precision, and is heavy, making it difficult to meet the core requirements of lightweight and efficient manufacturing for new energy vehicles. Summary of the Invention

[0003] This application provides a method for manufacturing an integrated die-cast front engine compartment in a single mold, aiming to solve the problems of complex manufacturing processes, large weight, and low efficiency in the prior art, and to achieve the manufacturing goals of lightweight, high strength, and high efficiency.

[0004] In a first aspect, this application provides a method for preparing a two-piece integrated die-casting front engine compartment, comprising the following steps: The molten aluminum alloy is injected into a two-cavity die-casting mold arranged in a centrally symmetrical manner to die-cast two symmetrically distributed integrated front engine compartment blanks. The integrated front engine compartment blank was cut off, the gating system and overflow channel were removed, and the burrs and flash were cleaned to separate it into two independent front engine compartments. The gating system of the cavity adopts a centrally symmetrical design.

[0005] This application utilizes a centrally symmetrical arrangement of mold cavities and a centrally symmetrical gating system to ensure consistent flow paths and uniform temperature and pressure distribution of the molten metal when filling both cavities, thereby guaranteeing consistent internal quality and mechanical properties of the two castings. The mold integrates a high-efficiency vacuum system and a local extrusion mechanism to eliminate porosity and shrinkage defects. This application, through integrated die casting, eliminates the overlapping edges and reinforcing components of traditional welded structures, maximizing material utilization. It simplifies the process, reducing the number of parts from 38 to 1, minimizing weld points and bolt connections, and significantly reducing manufacturing complexity. It enhances structural strength; integrated molding avoids the heat-affected zone of welding, increasing structural rigidity and improving collision safety. It improves production efficiency; the two-piece design in a single mold allows for the die casting of two front chambers in one operation, nearly doubling production efficiency. It saves costs by reducing stamping, welding, and assembly processes, lowering labor, equipment, and mold costs.

[0006] In some embodiments, the number of gates in the gating system of the cavity is 6 to 12 (the ratio of runner volume to casting volume is approximately 1:0.4). This number of gates effectively disperses the filling path of the molten metal, shortens the flow distance from each gate to the farthest end of the cavity, reduces filling resistance, avoids localized eddies and air entrapment, and simultaneously ensures the synchronous convergence of the leading edges of multiple molten metal streams, reducing cold shuts and flow marks; and / or, The gating system of the mold cavity has 25 to 40 overflow channels (the volume ratio of the overflow system to the casting is approximately 1:0.05). Within this range, the overflow channels can fully accommodate the cold, sludge-laden molten metal mixed with gas during the initial filling stage. Simultaneously, the overflow channels act as a buffer zone for venting, significantly reducing the back pressure inside the mold cavity. This facilitates the removal of microscopic pores and oxide inclusions, improving the density and surface quality of the casting; and / or, The gating system of the cavity adopts an H-shaped symmetrical design. The H-shaped symmetrical design allows the molten aluminum to flow from the center to both sides for symmetrical filling, achieving synchronous advancement of the filling front and left-right balance of pressure distribution. This avoids hot spot offset or air entrapment caused by unidirectional filling, while reducing the tendency of mold thermal fatigue and improving the dimensional consistency of the casting.

[0007] In some embodiments, the melting temperature of the aluminum alloy is 680°C to 720°C. Within this range, the melting temperature of the aluminum alloy can minimize the hydrogen absorption tendency of the melt and the amount of oxide slag generated, while ensuring that the alloy is fully melted and has good fluidity. At the same time, it can avoid grain coarsening and loss of alloying elements (such as magnesium) caused by high temperature.

[0008] Aluminum alloys can be selected from MYZAISi7MnMg (by mass fraction, Si: 6.5%~7.5%, Cu: ≤0.05%, Mn: 0.2%~0.6%, Mg: 0.2%~0.6%; Fe: ≤0.25%, Zn ≤0.05%, other impurities ≤0.15%, balance Al) and MYZAISi7MnMgZn (by mass fraction, Si: 6.5%~8.5%, Cu: ≤0.10%, Mn: 0.5%~0.8%, Mg: 0.1%~0.5%; Fe: ≤0.30%, Zn: 0.1%~1.0%, rare earth elements 0.01%~0.2%, Sr: 0.02%~0.05%, other impurities ≤0.15%, balance Al). The following are the impurities: (Al content), MYZAISi9Mn-MgMoCrZr (by mass fraction, Si: 8.0%~9.5%, Cu: ≤0.10%, Mn: 0.3%~0.8%, Mg: 0.1%~0.3%; Fe: ≤0.30%, Zn≤0.1%, Ti: 0.05%~0.2%, Zr: 0.05%~0.2%, Cr: 0.05%~0.2%, Mo: 0.05%~0.3%, Sr: 0.01%~0.03%, other impurities ≤0.15%, balance Al), MYZAISi9MnMgCu (by mass fraction, Si: 8.0%~10.0%, Cu: 0.05%~0.5%, Mn: 0.5%~0.05%). 8%, Mg: 0.1%~0.5%; Fe: ≤0.20%, Zn≤0.05%, rare earth elements 0.02%~0.06%, Sr: 0.005%~0.03%, other impurities ≤0.15%, balance Al), MYZAISi9MnZrV (by mass fraction, Si: 8.5%~9.5%, Cu: ≤0.05%, Mn: 0.4%~0.6%, Mg≤0.05%; Fe: ≤0.20%, Zn≤0.05%, Ti: 0.1%~0.2%, Zr: 0.1%~0.2%, V: 0.1%~0.2%, Sr: 0.01%~0.06%, other impurities ≤0.15%, balance Al), MYZAISi9 MnZr (by mass fraction, Si: 8.5%~10.0%, Mn: 0.3%~0.6%, Mg≤0.1%; Fe: ≤0.15%, Zn≤0.08%, Ti: 0.04%~0.15%, Zr: 0.1%~0.2%, V≤0.1%, Sr: 0.008%~0.015%, other impurities ≤0.15%, balance Al), MYZAISi9MnZrMo (by mass fraction, Si: 9.0%~10.0%, Cu: ≤0.03%, Mn: 0.35%~0.6%, Mg≤0.06%; Fe: ≤0.15%, Zn≤0.05%, Ti: 0.06%~0.15%, Zr: 0.1%~0.06%)2%, Mo: 0.015%~0.035%, Sr: 0.015%~0.025%, other impurities ≤0.15%, balance Al) are any one of the following:

[0009] In some embodiments, the injection rate of die casting is 4m / s to 6m / s. Within this range, the injection rate of die casting can provide sufficient high-speed filling kinetic energy, allowing the molten metal to fill the complex thin-walled cavity in a very short time, avoiding cold shuts caused by premature solidification. At the same time, this rate range is within a reasonable window for conventional vacuum die casting, which can suppress air entrapment and reduce erosion of the mold.

[0010] In some embodiments, the pressurization pressure of die casting is 35MPa~50MPa. Within this range, the pressurization pressure of die casting can exert a strong compaction effect on the melt during solidification, break dendrites, and force feeding.

[0011] In some embodiments, the vacuum degree of die casting is ≤50mbar. Within this range, the initial gas content in the mold cavity and pressure chamber can be reduced to an extremely low level, which greatly reduces the probability of gas being entrained in the melt during high-speed filling and reduces porosity defects inside the die casting from the source.

[0012] In some embodiments, the die-casting filling time is 50ms to 70ms. Within this range, the molten metal can be rapidly filled under controllable turbulence, avoiding cold shuts caused by excessive cooling of the front metal due to excessive filling time or air jetting caused by insufficient filling time. This time window matches the injection rate of 4 m / s to 6 m / s, which is beneficial for obtaining a smooth surface and clear flow channel.

[0013] In some embodiments, the holding time for die casting is 5s to 12s. Within this range, the holding time allows the metal in thick-walled sections and near the gate to solidify fully under pressure, preventing backflow or shrinkage cavities after pressure is withdrawn. At the same time, this duration balances production efficiency with the reliability of complete solidification of the casting, avoiding internal porosity caused by insufficient holding pressure or gate shearing difficulties caused by excessive holding pressure.

[0014] In some embodiments, standard connectors are embedded inside the front engine compartment for direct bolt connections to external components. Embedded standard connectors allow for quick assembly and disassembly of external functional modules (such as cooling modules, headlights, bumpers, etc.), avoiding tapping or welding on thin-walled or composite structures, reducing stress concentration at connection points, and improving assembly accuracy and ease of maintenance.

[0015] In some embodiments, the front engine compartment surface is designed with adhesive grooves for applying structural adhesive to connect other body parts. These adhesive grooves replace the spot welding sealant and MIG welding used in traditional sheet metal structures.

[0016] In some embodiments, the front engine compartment is provided with multiple self-piercing riveting connection points for connection with high-strength steel plates. Self-piercing riveting connection points enable mechanical interlocking connections between dissimilar materials (such as aluminum alloy and high-strength steel) without the need for pre-drilling, avoiding material phase changes or thermal deformation caused by heat input, and effectively preserving the original mechanical properties of the high-strength steel plate. Simultaneously, this process possesses high shear and peel resistance, making it suitable for vehicle body joint areas subjected to complex loads.

[0017] In some embodiments, a coating surface may be provided in the stone-impact-prone area for applying stone-impact-resistant adhesive to improve durability. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a centrally symmetrically arranged two-cavity die-casting mold cavity, which is a method for preparing an integrated die-casting front chamber of a two-part mold according to an embodiment of this application.

[0020] Figure 2 This is a schematic diagram of the front engine compartment structure obtained by the preparation method of the integrated die-casting front engine compartment of Embodiment 1 of this application. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] Traditional automotive engine compartments typically employ sheet metal stamping and welding structures, usually composed of dozens of sheet metal parts connected by welds, bolts, and structural adhesives. For example, a front engine compartment structure may require 38 parts welded together, containing as many as 469 weld points, and utilizing numerous standard parts (such as 84 M8 rivet nuts) and over 9 meters of spot welding sealant, resulting in an overall weight of 43 kg. This manufacturing method is complex, has low assembly precision, and is heavy, making it difficult to meet the core requirements of lightweight and efficient manufacturing for new energy vehicles.

[0023] In recent years, integrated die casting technology has been gradually applied to the manufacturing of vehicle body structural components. However, existing technologies mostly operate on a one-mold-one-piece production model, leaving room for improvement in production efficiency. Furthermore, the structural design, gating system, and connection methods of integrated die castings differ fundamentally from traditional sheet metal parts. Ensuring casting quality and simplifying subsequent connection processes within a highly efficient one-mold-two-piece production model is a pressing issue that needs to be addressed.

[0024] For example, a front engine compartment module and vehicle include: an integrated die-cast engine compartment, comprising a transverse main beam and two symmetrically mounted supporting components at the ends of the main beam, each supporting component including a longitudinal beam; two symmetrically arranged suspension systems, each suspension system including a brake-steering knuckle assembly, an upper control arm, and a lower control arm; wherein each brake-steering knuckle assembly is assembled with its corresponding supporting component, and the upper and lower control arms are both connected to the same longitudinal beam. By integrating the subframe into the front engine compartment module to provide connection points, a highly integrated design is achieved, reducing the number of parts and assembly time, and improving the overall vehicle lightweighting level. However, it adopts the traditional one-mold-one-piece die-casting mode, where only one front engine compartment can be produced in a single die-casting cycle. For mass-produced models, more die-casting machines and molds are required, failing to maximize equipment utilization and production efficiency. The final assembly workshop still requires complex connection processes, making it difficult to guarantee the yield and consistency during mass production.

[0025] For example, a front engine compartment structure and vehicle include: a support assembly, including a suspension spring mounting plate, with a hollowed-out annular mounting member in the middle of the suspension spring mounting plate, the annular mounting member including a through hole in the middle, and a first connecting structure arranged in a ring around the annular mounting member; the suspension spring mounting assembly includes a base structure and a mounting structure disposed on the base structure, the mounting structure being used to fix the suspension spring. Through the first and second connecting structures, the annular mounting member can be matched with suspension spring mounting assemblies with different mounting structures, allowing the same front engine compartment structure to be used on vehicles of different models or specifications, improving the versatility and replaceability of parts, and possessing modular design capabilities. However, it adopts a split design, with the support assembly and suspension spring mounting assembly being two independent components, requiring assembly via a connecting structure. While this design improves versatility, it adds additional connecting parts and assembly processes. The split design requires manufacturing each component separately before assembly, increasing manufacturing processes and costs. The use of multiple connecting structures such as mortises, tenons, and bolt connections results in a large number of connection points, posing a potential risk of loosening.

[0026] To address the problems of low production efficiency, complex internal connections, heavy weight, and lengthy processes in the existing technologies, this application provides a method for manufacturing an integrated die-casting front chamber consisting of two parts in a single mold. This method not only significantly reduces weight and simplifies the structure through integrated design, but also significantly improves production efficiency while ensuring high casting quality through the two-part mold design. Furthermore, this application optimizes the connection structure design of the casting itself, greatly reducing the complexity of subsequent connections with other components, such as eliminating MIG welding and reducing the use of SPR (Silicone Plasma Reinforcement).

[0027] The front nacelle integrates the left rear longitudinal beam, front bulkhead crossbeam, and front floor front end, etc. The original more than 50 sheet metal parts are formed into a large aluminum alloy die casting through an integrated die casting process. The die casting is connected to the surrounding parts using SPR and bolt connection scheme.

[0028] In a first aspect, this application provides a method for preparing a two-piece integrated die-casting front engine compartment, comprising the following steps: The molten aluminum alloy is injected into a two-cavity die-casting mold arranged in a centrally symmetrical manner to die-cast two symmetrically distributed integrated front engine compartment blanks. The integrated front engine compartment blank was cut off, the gating system and overflow channel were removed, and the burrs and flash were cleaned to separate it into two independent front engine compartments. The gating system of the cavity adopts a centrally symmetrical design.

[0029] This application utilizes a centrally symmetrical arrangement of mold cavities and a centrally symmetrical gating system to ensure consistent flow paths and uniform temperature and pressure distribution of the molten metal as it fills both cavities, thereby guaranteeing consistent internal quality and mechanical properties of the two castings. The mold integrates a highly efficient vacuum system and a local extrusion mechanism to eliminate porosity and shrinkage defects. Figure 1 As shown, this application utilizes integrated die casting to eliminate the overlapping edges and reinforcing components of traditional welded structures, maximizing material utilization. It simplifies the process, reducing the number of parts from 38 to 1, minimizing weld points and bolt connections, and significantly reducing manufacturing complexity. It enhances structural strength; the integrated molding avoids the heat-affected zone of welding, increasing structural rigidity and improving collision safety. It improves production efficiency; the two-piece design in a single mold allows for the die casting of two front chambers, nearly doubling production efficiency. It saves costs by reducing stamping, welding, and assembly processes, lowering labor, equipment, and mold costs.

[0030] In conjunction with the first aspect, in some embodiments provided in this application, the number of gates in the gating system of the cavity is 6 to 12 (the volume ratio of the runner to the casting is approximately 1:0.4). The number of gates in the gating system of the cavity is within this range, which can effectively disperse the filling path of the molten metal, shorten the flow distance from each gate to the farthest end of the cavity, reduce the filling resistance, avoid local eddies and air entrapment, and at the same time ensure that the leading edges of multiple streams of molten metal converge synchronously, reducing cold shuts and flow marks.

[0031] In conjunction with the first aspect, in some embodiments provided in this application, the overflow channels of the gating system of the cavity are 25 to 40 (the volume ratio of the overflow system to the casting is approximately 1:0.05). Within this range, the overflow channels of the gating system of the cavity can fully accommodate the cold molten metal mixed with gas in the early stage of filling. At the same time, the overflow channels are used as a buffer zone for venting, which significantly reduces the back pressure inside the cavity, which is conducive to the discharge of micropores and oxide inclusions from the cavity, thereby improving the density and surface quality of the casting.

[0032] In conjunction with the first aspect, in some embodiments provided in this application, the gating system of the cavity adopts an H-shaped symmetrical design. The H-shaped symmetrical design allows the molten aluminum to flow symmetrically from the center to both sides, achieving synchronous advancement of the filling front and left-right balance of pressure distribution. This avoids hot spot shifts or air entrapment caused by unidirectional filling, while also reducing the tendency for mold thermal fatigue and improving the dimensional consistency of the casting.

[0033] In conjunction with the first aspect, in some embodiments provided in this application, the melting temperature of the aluminum alloy is 680℃~720℃. The melting temperature of the aluminum alloy within this range can minimize the hydrogen absorption tendency of the melt and the amount of oxide slag generated, while ensuring that the alloy is fully melted and has good fluidity, and at the same time avoid grain coarsening and loss of alloying elements (such as magnesium) caused by high temperature.

[0034] In conjunction with the first aspect, in some embodiments provided in this application, the aluminum alloy may be selected from MYZAISi7MnMg (by mass fraction, Si: 6.5%~7.5%, Cu: ≤0.05%, Mn: 0.2%~0.6%, Mg: 0.2%~0.6%; Fe: ≤0.25%, Zn ≤0.05%, other impurities ≤0.15%, balance Al) and MYZAISi7MnMgZn (by mass fraction, Si: 6.5%~8.5%, Cu: ≤0.10%, Mn: 0.5%~0.8%, Mg: 0.1%~0.5%; Fe: ≤0.30%, Zn: 0.1%~1.0%, rare earth elements 0.01%~0.2%, Sr: 0.0%). 2%~0.05%, other impurities ≤0.15%, balance Al), MYZAISi9Mn-MgMoCrZr (by mass fraction, Si: 8.0%~9.5%, Cu: ≤0.10%, Mn: 0.3%~0.8%, Mg: 0.1%~0.3%; Fe: ≤0.30%, Zn≤0.1%, Ti: 0.05%~0.2%, Zr: 0.05%~0.2%, Cr: 0.05%~0.2%, Mo: 0.05%~0.3%, Sr: 0.01%~0.03%, other impurities ≤0.15%, balance Al), MYZAISi9MnMgCu (by mass fraction, Si: 8.0%~10.0%, Cu: 2%~0.05 ... 0.05%~0.5%, Mn: 0.5%~0.8%, Mg: 0.1%~0.5%; Fe: ≤0.20%, Zn≤0.05%, rare earth elements 0.02%~0.06%, Sr: 0.005%~0.03%, other impurities ≤0.15%, balance Al), MYZAISi9MnZrV (by mass fraction, Si: 8.5%~9.5%, Cu: ≤0.05%, Mn: 0.4%~0.6%, Mg≤0.05%; Fe: ≤0.20%, Zn≤0.05%, Ti: 0.1%~0.2%, Zr: 0.1%~0.2%, V: 0.1%~0.2%, Sr: 0.01%~0.06%, other impurities ≤ 0.15%, balance Al), MYZAISi9MnZr (by mass fraction, Si: 8.5%~10.0%, Mn: 0.3%~0.6%, Mg≤0.1%; Fe: ≤0.15%, Zn≤0.08%, Ti: 0.04%~0.15%, Zr: 0.1%~0.2%, V≤0.1%, Sr: 0.008%~0.015%, other impurities ≤0.15%, balance Al), MYZAISi9MnZrMo (by mass fraction, Si: 9.0%~10.0%, Cu: ≤0.03%, Mn: 0.35%~0.6%, Mg≤0.06%; Fe: ≤0.15%, Zn≤0.05%, Ti: ...The composition of the following components is as follows: 0.06%~0.15%, Zr: 0.1%~0.2%, Mo: 0.015%~0.035%, Sr: 0.015%~0.025%, other impurities ≤0.15%, balance Al.

[0035] In conjunction with the first aspect, in some embodiments provided in this application, the injection rate of die casting is 4m / s to 6m / s. Within this range, the injection rate of die casting can provide sufficient high-speed filling kinetic energy, allowing the molten metal to fill the complex thin-walled cavity in a very short time, avoiding cold shuts caused by premature solidification. At the same time, this rate range is within a reasonable window for conventional vacuum die casting, which can suppress air entrapment and reduce erosion of the mold.

[0036] In conjunction with the first aspect, in some embodiments provided in this application, the pressurization pressure of die casting is 35MPa~50MPa. Within this range, the pressurization pressure of die casting can exert a strong compaction effect on the melt during solidification, break dendrites, and force feeding.

[0037] In conjunction with the first aspect, in some embodiments provided in this application, the vacuum degree of die casting is ≤50mbar. Within this range, the initial gas content in the mold cavity and pressure chamber can be reduced to an extremely low level, which greatly reduces the probability of gas being entrained in the melt during high-speed filling and reduces porosity defects inside the die casting from the source.

[0038] In conjunction with the first aspect, in some embodiments provided in this application, the die-casting filling time is 50ms to 70ms. Within this range, the molten metal can be rapidly filled under controllable turbulence, avoiding cold shuts caused by excessive cooling of the front metal due to excessive filling time or air jetting caused by insufficient filling time. This time window matches the injection rate of 4 m / s to 6 m / s, which is beneficial for obtaining a smooth surface and clear flow channel.

[0039] In conjunction with the first aspect, in some embodiments provided in this application, the holding time for die casting is 5s to 12s. Within this range, the holding time allows the metal in thick-walled sections and near the gate to fully solidify under pressure, preventing backflow or shrinkage cavities after pressure withdrawal. Simultaneously, this duration balances production efficiency with the reliability of complete casting solidification, avoiding internal porosity caused by insufficient holding pressure or gate shearing difficulties caused by excessive holding pressure.

[0040] In conjunction with the first aspect, in some embodiments provided in this application, a standard connector is embedded inside the front engine compartment for direct bolt connection of external components. The embedded standard connector allows for quick assembly and disassembly of external functional modules (such as cooling modules, headlights, bumpers, etc.), avoiding tapping or welding on thin-walled or composite structures, reducing stress concentration at connection points, and improving assembly accuracy and maintenance convenience.

[0041] In conjunction with the first aspect, in some embodiments provided in this application, the front engine compartment surface is designed with a glue groove structure for applying structural adhesive to connect other body parts. The glue groove structure can apply structural adhesive to connect other body parts, replacing the spot welding sealant and MIG welding used in traditional sheet metal structures.

[0042] In conjunction with the first aspect, in some embodiments provided in this application, the front engine compartment is provided with multiple self-piercing riveting connection points for connection with high-strength steel plates. Self-piercing riveting connection points can achieve mechanical interlocking connections between dissimilar materials (such as aluminum alloy and high-strength steel), eliminating the need for pre-drilling holes, avoiding material phase changes or thermal deformation caused by heat input, and effectively preserving the original mechanical properties of the high-strength steel plate; simultaneously, this process possesses high shear and peel resistance, making it suitable for vehicle body joint areas subjected to complex loads.

[0043] In conjunction with the first aspect, in some embodiments provided in this application, a coating surface may also be provided in the area susceptible to stone impact for coating with anti-stone impact adhesive to improve durability.

[0044] The present application will be further described below with reference to specific embodiments.

[0045] Example 1: Taking the front engine compartment of a certain new energy vehicle as an example, such as Figure 2 As shown, the preparation method of the front engine compartment using a one-mold, two-piece integrated die-casting process includes the following steps: Mold Design: Design a two-cavity die-casting mold with symmetrical arrangement of cavities in the center. The gating system adopts an H-shaped symmetrical design with 8 gates (4 per cavity) and 32 overflow channels (16 per cavity).

[0046] Die casting parameters: C611 heat-free aluminum alloy is used, with a melting temperature of 700±10℃. After degassing and refining, it is injected into the mold cavity under the following conditions: injection speed of 5m / s, pressurization pressure of 40MPa, vacuum degree ≤50mbar, filling time of 65ms, and holding time of 10s.

[0047] Post-processing: Remove the gating system and overflow channel, and clean off burrs and flash.

[0048] Finished product inspection: The manufactured front engine compartment weighs 28kg, with a dimensional tolerance of ±0.5mm. It is tested according to GB / T 228.1-2021 Metallic materials - Tensile testing - Part 1: Test method at room temperature. The tensile strength Rm ≥ 260 MPa, yield strength Rp0.2 ≥ 180 MPa, and elongation after fracture A ≥ 8%.

[0049] The resulting integrated front engine compartment integrates all functional structures, including the front shock absorber tower, front longitudinal beams, front crossbeams, front wheel arches, front bumper beam mounting points, front suspension mounting points, front engine compartment lock mounting points, and front headlight mounting points. Crucially, to simplify the assembly process, this integrated casting incorporates multiple pre-integrated connection interfaces in its structural design. Integrated standard parts: Various standard connectors are embedded inside the casting through a post-processing step for direct bolt connection of external components.

[0050] Optimized adhesive coating structure: The casting surface is designed with a specific adhesive groove structure for coating structural adhesive (total length 4134.503mm) to connect other body parts, replacing the spot welding sealant (9363.659mm) and MIG welding (653.967mm) in the traditional sheet metal structure.

[0051] SPR connection interface: 16 SPR (self-piercing riveting) connection points are designed in key stress-bearing parts for connection with high-strength steel plates to enhance the overall structural strength.

[0052] Stone-impact resistant coating: A 0.377m thick layer is designed in the bottom area prone to stone impact. 2 The coating surface is used to coat the stone chip mortar, improving durability.

[0053] Comparative Example 1 The sheet metal stamping and welding process is adopted, and the specific steps are as follows: Multiple steel plates were stamped into 38 sheet metal parts. These parts were then assembled and welded using 469 weld points, 52 standard parts (including M6 nuts, M8 rivet nuts, M6 rivet nuts, M12 nuts, M15 studs, M14 threaded sleeves, M6 studs, M6 bolts, etc.), a total length of 9363.659 mm of spot welding sealant, 2714.874 mm of structural adhesive, and 653.967 mm of MIG welding. Finally, surface treatment was performed to obtain the forward engine compartment.

[0054] Table 1 shows a comparison of the forward nacelle performance of Example 1 and Comparative Example 1.

[0055] Table 1 Comparison of the forward engine compartment of Example 1 and Comparative Example 1

[0056] The internal connection of Example 1 contains 33 standard parts, including 21 M8 rivet nuts, 2 M6 rivet nuts, 8 M12 threaded sleeves and 2 M12 nuts.

[0057] The internal connection of Comparative Example 1 contains 52 standard parts, including M6 nuts, M8 rivet nuts, M6 rivet nuts, M12 nuts, M15 studs, M14 threaded sleeves, M6 studs, M6 bolts, etc.

[0058] In summary, the preparation method of the two-piece integrated die-casting front engine compartment of this application has the following advantages: Significant weight reduction: It is about 35% (28kg) lighter than the traditional sheet metal structure (43kg), which helps to improve the driving range of new energy vehicles. Through integrated die casting, the overlapping edges and reinforcements of the traditional welded structure are eliminated, maximizing the utilization of materials.

[0059] Simplified process: The number of parts is reduced from 38 to 1, reducing welding points and bolt connections, significantly reducing manufacturing complexity.

[0060] Enhanced structural strength: One-piece molding avoids the heat-affected zone of welding, increasing structural rigidity and enhancing collision safety.

[0061] Improve production efficiency: The two-piece design allows for the single die-casting of two front chambers, nearly doubling production efficiency.

[0062] Cost savings: Reduce stamping, welding, assembly and other processes to lower labor, equipment and mold costs.

[0063] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0064] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0065] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0066] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0067] The above are merely preferred embodiments of this application and do not limit the scope of this application. Any equivalent structural or procedural transformations made based on the description and drawings of this application, or direct or indirect applications in other related technical fields, are similarly included within the scope of protection of this application.

Claims

1. A method for preparing a two-piece integrated die-casting front chamber, characterized in that, Includes the following steps: The molten aluminum alloy is injected into a two-cavity die-casting mold arranged in a centrally symmetrical manner to die-cast two symmetrically distributed integrated front engine compartment blanks. The integrated front engine compartment blank was cut off, the gating system and overflow channel were removed, and the burrs and flash were cleaned to separate it into two independent front engine compartments. The gating system of the cavity adopts a centrally symmetrical design.

2. The method for preparing the integrated die-casting front chamber of a single mold and two parts as described in claim 1, characterized in that: The gating system of the cavity has 6 to 12 gates; and / or, The number of overflow channels in the gating system of the cavity is 25 to 40.

3. The method for preparing the integrated die-casting front chamber of a single mold and two parts as described in claim 1, characterized in that, The gating system of the cavity adopts an H-shaped symmetrical design.

4. The method for preparing the integrated die-casting front chamber of a single mold and two parts as described in claim 1, characterized in that, The melting temperature of aluminum alloys is 680℃~720℃.

5. The method for preparing the integrated die-casting front chamber of a single mold and two parts as described in claim 1, characterized in that: The injection rate for die casting is 4 m / s to 6 m / s; and / or, The pressurization pressure for die casting is 35MPa~50MPa.

6. The method for preparing the integrated die-casting front chamber of a single mold and two parts as described in claim 1, characterized in that, The vacuum level for die casting is ≤50mbar.

7. The method for preparing the integrated die-casting front chamber of a single mold and two parts as described in claim 1, characterized in that, The filling time for die casting is 50ms~70ms; and / or, The holding time for die casting is 5s to 12s.

8. The method for preparing the integrated die-casting front chamber of a single mold and two parts as described in claim 1, characterized in that, The forward engine compartment is equipped with standard connectors for direct bolt connections to external components.

9. The method for preparing the integrated die-casting front chamber of a two-piece die-casting unit as described in claim 1, characterized in that, The front engine compartment surface is designed with adhesive grooves for applying structural adhesive to connect other body parts.

10. The method for preparing the integrated die-casting front chamber of a single mold and two parts as described in claim 1, characterized in that, The forward engine compartment is equipped with multiple self-piercing riveting connection points for connection with high-strength steel plates.

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