Automobile nodular cast iron casting device and method

Abstract

The invention relates to the technical field of casting, in particular to an automobile nodular cast iron casting device and method.The automobile nodular cast iron casting device comprises an air cooling assembly and a water cooling assembly, the air cooling assembly comprises a cooling fan, a cooling motor, an air inlet channel, an air outlet channel, first blades, a transmission shaft and stirring blades, and the air inlet channel and the air outlet channel are formed in the top of an upper mold; the cooling fan is rotationally arranged between the air inlet channel and the air outlet channel, the output end of the cooling motor is connected with the cooling fan, the first blade is arranged in the air inlet channel, and the transmission shaft is fixedly connected with the first blade and penetrates through the air inlet channel and the stirring blade to be connected with the transmission shaft; the water cooling assembly comprises a water cooling box, a liquid circulation channel, a circulation pump and a cooler, the water cooling box is arranged below the lower die and fixed to the base, the liquid circulation channel is communicated with the water cooling box, the circulation pump is communicated with the liquid circulation channel, the cooler is communicated with the circulation pump, heat dissipation can be conducted on the top and the bottom of the die at the same time, and therefore the casting quality is improved.

Description

Technical Field

[0001] This invention relates to the field of casting technology, and in particular to an apparatus and method for casting ductile iron for automobiles. Background Technology

[0002] The automotive ductile iron casting equipment is a precision casting device specifically designed for producing automotive parts such as crankshafts, connecting rods, wheel hubs, and chassis components. It primarily utilizes the excellent mechanical properties of ductile iron (VB) (such as high strength, high toughness, good wear resistance, and vibration damping) to manufacture critical components that withstand high stress.

[0003] After the ductile iron casting is completed, the casting needs to undergo a critical cooling and solidification process in the mold. Existing cooling measures mainly focus on the side walls and bottom of the mold, usually using water cooling channels or air cooling systems to cool the outside of the mold, while often neglecting the effective cooling of the top of the mold (i.e., the gate area and the upper surface of the casting). This can easily lead to internal defects such as shrinkage cavities and porosity in the top or hot spots of the casting, reducing the overall mechanical properties and service life of the casting. Summary of the Invention

[0004] The purpose of this invention is to provide an automotive ductile iron casting apparatus and method, which aims to simultaneously dissipate heat from the top and bottom of the mold, thereby improving the casting quality.

[0005] To achieve the above objectives, in a first aspect, the present invention provides an automotive ductile iron casting device, comprising a base, a support frame, an upper mold, and a lower mold. The support frame is fixedly connected to the base and located on one side of the base. The upper mold is slidably disposed on the support frame, and the lower mold is disposed below the upper mold. The device also includes an air-cooling assembly and a water-cooling assembly. The air-cooling assembly includes a cooling fan, a cooling motor, an air inlet, an air outlet, a first blade, a drive shaft, and a stirring blade. The air inlet and the air outlet are disposed on the top of the upper mold. The cooling fan is rotatably disposed between the air inlet and the air outlet. The output end of the cooling motor is connected to the cooling fan. The first blade is disposed within the air inlet. The drive shaft is fixedly connected to the first blade and passes through the air inlet. The stirring blade is connected to the drive shaft. The water-cooling assembly includes a water-cooling tank, a liquid circulation channel, a circulation pump, and a cooler. The water-cooling tank is located below the lower mold and fixed on the base. The liquid circulation channel is connected to the water-cooling tank, the circulation pump is connected to the liquid circulation channel, and the cooler is connected to the circulation pump.

[0006] The upper mold includes a hydraulic cylinder, a drive rod, and an upper mold body. The drive rod is connected to the upper mold body, the hydraulic cylinder is fixed on the support frame, and the output end of the hydraulic cylinder is connected to the drive rod.

[0007] The lower mold includes a lower mold body, a sliding column, a support column, and a support spring. The support column is fixed on the base. The sliding column is slidably connected to the support column and is located on the top of the support column. The lower mold body is fixed on the sliding column. The support spring is disposed between the sliding column and the support column.

[0008] The lower mold also includes a plurality of first heat sinks, which are fixed to the outside of the lower mold body.

[0009] The air-cooling assembly also includes an auxiliary blade group, which is disposed on one side of the drive shaft.

[0010] The auxiliary blade assembly includes a driving gear, a driven gear, a driven rod, and a driven blade. The driving gear is fixed to the transmission shaft, the driven gear meshes with the driving gear, the driven rod is connected to the driven gear, and the driven blade is fixedly connected to the driven rod.

[0011] The water-cooled box includes a box body, a contact baffle, and a nozzle. The contact baffle is disposed inside the box body and close to the lower mold body, and the nozzle is disposed on the contact baffle.

[0012] The water-cooled box further includes a reflux spiral tube, an absorption chamber, an exhaust pipe, and a vent valve. The reflux spiral tube is connected to the box body and the absorption chamber. The exhaust pipe is located at the top of the absorption chamber, and the vent valve is located on one side of the exhaust pipe. The absorption chamber is connected to the liquid circulation channel.

[0013] The water-cooled box also includes a plurality of second heat sinks, which are disposed on the absorption cavity.

[0014] Secondly, the present invention also provides a method for casting ductile iron for automobiles, using the aforementioned casting apparatus for ductile iron for automobiles.

[0015] This invention discloses an automotive ductile iron casting apparatus and method. The base serves as the fundamental load-bearing structure of the entire apparatus, possessing excellent stability and seismic resistance, and is used to support and fix other components. The support frame is fixedly connected to the base and vertically positioned on one side of the base. Its structure is made of high-strength metal material to ensure structural stability under high-temperature and high-load conditions. The upper mold is slidably mounted on the support frame and can move up and down along the support frame via a hydraulic or pneumatic drive device, enabling mold closing and opening operations with the lower mold, facilitating the forming and demolding of the casting.

[0016] The lower mold is located directly below the upper mold and fixed to the base, forming a closed cavity with the upper mold to accommodate ductile iron material in a high-temperature molten state.

[0017] The air-cooling assembly is located in the upper mold area and is mainly used for forced convection cooling of the upper surface of the casting and the top of the cavity. The air inlet and outlet are respectively located on the top sides of the upper mold, and the internal channels connect the external environment with the space above the cavity. The cooling fan is located in the transition area between the air inlet and outlet, and its drive end is connected to the output shaft of the cooling motor. Driven by the cooling motor, it rotates at high speed, creating a negative pressure suction effect, drawing in ambient temperature air through the air inlet and expelling it through the air outlet, thus achieving airflow circulation.

[0018] When the cooling fan is running, it drives the drive shaft to rotate synchronously through a gear or belt drive mechanism, thereby driving the stirring blades to agitate in the water-cooling assembly, promoting the mixing of high-temperature liquid and low-temperature liquid, and significantly improving heat dissipation efficiency.

[0019] The water-cooled tank is located below the lower mold and is securely fixed to the base by bolts or welding. It is filled with coolant (such as water or antifreeze) and fits tightly against the bottom of the lower mold, forming a good heat conduction path. The liquid circulation channel is embedded inside the lower mold or surrounds its outer perimeter, communicating with the water-cooled tank to form a closed coolant flow loop.

[0020] The circulating pump is installed in the pipeline of the liquid circulation channel to provide power and drive the coolant to continuously circulate between the water-cooled tank, the liquid circulation channel, and the cooler. After absorbing heat from the lower mold, the high-temperature coolant flows through the cooler, where it is cooled by air cooling or refrigerant heat exchange, and then returns to the water-cooled tank to participate in the cooling process again, thus achieving continuous heat removal.

[0021] This invention achieves comprehensive, gradient cooling control of automotive ductile iron castings during the casting process through the synergistic effect of air-cooling and water-cooling components. The air-cooling system effectively reduces the temperature at the top of the mold, while the water-cooling system quickly removes heat accumulated at the bottom. The combination of the two not only shortens the cooling cycle but also reduces internal stress and deformation tendency in the castings, improving product dimensional accuracy and surface quality. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a structural diagram of an automotive ductile iron casting device according to the present invention.

[0024] Figure 2 This is a right-side structural diagram of an automotive ductile iron casting device according to the present invention.

[0025] Figure 3 This is a left-side structural diagram of an automotive ductile iron casting device according to the present invention.

[0026] Figure 4 This is a first cross-sectional structural diagram of an automotive ductile iron casting device according to the present invention.

[0027] Figure 5 This is a second cross-sectional view of an automotive ductile iron casting device according to the present invention.

[0028] Figure 6 This is a third cross-sectional view of an automotive ductile iron casting device according to the present invention.

[0029] Base 101, support frame 102, upper mold 103, lower mold 104, cooling fan 105, cooling motor 106, air inlet 107, air outlet 108, first blade 109, drive shaft 110, stirring blade 111, water cooling box 112, liquid circulation channel 113, circulation pump 114, cooler 115, hydraulic cylinder 116, drive rod 117, upper mold body 118, lower mold body 119, sliding column 120, support column 121, support spring 122, first heat sink 123, driving gear 124, driven gear 125, driven rod 126, driven blade 127, box body 128, contact baffle 129, nozzle 130, return spiral tube 131, absorption chamber 132, air outlet pipe 133, vent valve 134, second heat sink 135. Detailed Implementation

[0030] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0031] In the description of this invention, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention 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 the invention. Furthermore, in the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0032] First Embodiment Please see Figures 1-6 This invention provides an automotive ductile iron casting device, including a base 101, a support frame 102, an upper mold 103, and a lower mold 104. The support frame 102 is fixedly connected to the base 101 and located on one side of the base 101. The upper mold 103 is slidably disposed on the support frame 102, and the lower mold 104 is disposed below the upper mold 103. The device also includes an air-cooling assembly and a water-cooling assembly. The air-cooling assembly includes a cooling fan 105, a cooling motor 106, an air intake duct 107, an air outlet duct 108, a first blade 109, a drive shaft 110, and a stirring blade 111. The air intake duct 107 and the air outlet duct 108 are disposed on the top of the upper mold 103, and the cooling fan 105 is rotatably disposed on the air intake duct 107 and the water outlet duct 108. Between the air outlets 108, the output end of the cooling motor 106 is connected to the cooling fan 105. The first blade 109 is disposed in the air inlet 107. The drive shaft 110 is fixedly connected to the first blade 109 and passes through the air inlet 107. The stirring blade 111 is connected to the drive shaft 110. The water cooling assembly includes a water cooling box 112, a liquid circulation channel 113, a circulation pump 114, and a cooler 115. The water cooling box 112 is disposed below the lower mold 104 and fixed on the base 101. The liquid circulation channel 113 is connected to the water cooling box 112. The circulation pump 114 is connected to the liquid circulation channel 113. The cooler 115 is connected to the circulation pump 114.

[0033] In this embodiment, the base 101 serves as the fundamental load-bearing structure of the entire device, possessing excellent stability and seismic resistance, and is used to support and fix other components. The support frame 102 is fixedly connected to the base 101 and is vertically arranged on one side of the base 101. Its structure is made of high-strength metal material to ensure structural stability under high temperature and high load conditions. The upper mold 103 is slidably disposed on the support frame 102 and can move up and down along the support frame 102 via a hydraulic or pneumatic drive device to realize mold closing and opening operations with the lower mold 104, facilitating the forming and demolding of castings.

[0034] The lower mold 104 is located directly below the upper mold 103 and fixed on the base 101. It cooperates with the upper mold 103 to form a closed cavity for accommodating ductile iron material in a high-temperature molten state.

[0035] The air-cooling component is located in the upper mold 103 area and is mainly used for forced convection cooling of the upper surface of the casting and the top of the cavity. The air inlet 107 and air outlet 108 are respectively located on the top sides of the upper mold 103, and the internal channels connect the external environment with the space above the cavity. The cooling fan 105 is rotatably located in the transition area between the air inlet 107 and the air outlet 108. Its drive end is connected to the output shaft of the cooling motor 106. Driven by the cooling motor 106, it rotates at high speed to form a negative pressure suction effect, drawing in ambient temperature air through the air inlet 107 and expelling it through the air outlet 108, thus achieving airflow circulation.

[0036] When the cooling fan 105 is running, it drives the drive shaft 110 to rotate synchronously through the gear or belt drive mechanism, thereby driving the stirring blades 111 to stir in the water cooling assembly, promoting the mixing of high-temperature liquid and low-temperature liquid, and significantly improving heat dissipation efficiency.

[0037] The water-cooled box 112 is located below the lower mold 104 and is firmly fixed to the base 101 by bolts or welding. It is filled with coolant (such as water or antifreeze) and fits tightly against the bottom of the lower mold 104, forming a good heat conduction path. The liquid circulation channel 113 is embedded inside the lower mold 104 or surrounds its outer perimeter and communicates with the water-cooled box 112, forming a closed coolant flow loop.

[0038] The circulating pump 114 is installed in the pipeline of the liquid circulation channel 113 to provide power and drive the coolant to continuously circulate between the water-cooled tank 112, the liquid circulation channel 113, and the cooler 115. After absorbing heat from the lower mold 104, the high-temperature coolant flows through the cooler 115, where it is cooled by air cooling or refrigerant heat exchange, and then returns to the water-cooled tank 112 to participate in the cooling process again, thus achieving continuous heat removal.

[0039] In summary, this invention achieves comprehensive, gradient cooling control of automotive ductile iron castings during the casting process through the synergistic effect of air-cooling and water-cooling components. The air-cooling system effectively reduces the temperature at the top of the mold, while the water-cooling system quickly removes heat accumulated at the bottom. The combination of the two not only shortens the cooling cycle but also reduces internal stress and deformation tendency in the castings, improving product dimensional accuracy and surface quality.

[0040] The upper mold 103 includes a hydraulic cylinder 116, a drive rod 117, and an upper mold body 118. The drive rod 117 is connected to the upper mold body 118. The hydraulic cylinder 116 is fixed on the support frame 102, and the output end of the hydraulic cylinder 116 is connected to the drive rod 117.

[0041] The upper mold body 118 is made of high-strength heat-resistant alloy steel and undergoes surface quenching or coating treatment, exhibiting excellent high-temperature resistance and thermal fatigue resistance. It can withstand the thermal shock of molten metal for extended periods without deformation or cracking. The lower surface of the upper mold body 118 is provided with a cavity surface that matches the contour of the ductile iron part to be formed. This cavity surface mates with the corresponding cavity on the lower mold 104, together forming a complete casting forming space. In addition, heating or cooling channels can be pre-embedded inside the upper mold body 118 as needed to adjust the mold temperature during the casting cycle, further improving the casting quality.

[0042] The drive rod 117 is a rigid connecting component, usually made of high-strength solid or hollow steel rod. One end of it is firmly connected to the top center of the upper mold body 118. Reliable assembly can be achieved by means of threaded connection, flange fixing or welding.

[0043] The hydraulic cylinder 116 is driven by an external hydraulic system and has the advantages of high output, smooth operation, and controllable speed, making it particularly suitable for the opening and closing of heavy molds. The output end (i.e., the piston rod) of the hydraulic cylinder 116 is connected to the upper end of the drive rod 117. The connection method can be a pin hinge or a rigid coupling, which can transmit push and pull forces and absorb minor offsets caused by assembly errors to a certain extent.

[0044] During operation, when mold closing is required, the hydraulic system supplies oil to the hydraulic cylinder 116, the piston rod extends downward, and through the drive rod 117 drives the upper mold body 118 to descend vertically along the guide rail or guide column on the support frame 102 until it is tightly fitted with the lower mold 104 to form a closed cavity, ready for pouring; after pouring is completed, after the casting has initially solidified, the hydraulic cylinder 116 moves in the opposite direction, the piston rod retracts, and the upper mold body 118 is lifted smoothly to complete the mold opening action, which facilitates subsequent part removal and cleaning.

[0045] The lower mold 104 includes a lower mold body 119, a sliding column 120, a support column 121, and a support spring 122. The support column 121 is fixed on the base 101. The sliding column 120 is slidably connected to the support column 121 and is located on the top of the support column 121. The lower mold body 119 is fixed on the sliding column 120. The support spring 122 is disposed between the sliding column 120 and the support column 121.

[0046] The lower mold 104 includes a lower mold body 119, a sliding column 120, a support column 121, and a support spring 122. The lower mold body 119 is precision machined from high-strength heat-resistant cast iron or alloy steel, and its upper surface is provided with a cavity structure that matches the ductile iron part to be formed. This cavity, together with the cavity of the upper mold body 118, constitutes a complete casting forming space.

[0047] The support columns 121 are vertically arranged cylindrical support structures, and there can be two, four or more of them, symmetrically distributed on the base 101. They are firmly fixed to the surface of the base 101 by bolts, welding or interference fit. The sliding column 120 is sleeved on the top of the support column 121, forming a sliding fit connection with the support column 121, and can slide up and down along the axial direction of the support column 121. The inner surface of the sliding column 120 can be provided with a wear-resistant bushing or coated with a friction-reducing coating to reduce friction loss and extend service life. A support spring 122 is provided between the sliding column 120 and the support column 121. The support spring 122 surrounds the outer periphery of the support column 121 or is provided in a spring cavity inside the support column 121. One end of the spring abuts against the bottom step surface of the sliding column 120, and the other end abuts against the shoulder of the support column 121 or the surface of the base 101. The support spring 122 is usually made of high-temperature resistant and fatigue-resistant alloy spring steel, which has good elastic recovery performance and long-term stability.

[0048] During the mold closing process, when the upper mold 103 presses down, the lower mold body 119 moves slightly downward along the support column 121 through the sliding column 120 under pressure, compressing the support spring 122, thereby forming a certain elastic buffer, effectively absorbing the impact force of mold closing and preventing the mold from being damaged by rigid collision; secondly, in the mold opening stage, the support spring 122 releases elastic potential energy, pushing the sliding column 120 and the lower mold body 119 to reset, which helps to create a small gap between the casting and the lower mold 104, facilitating demolding operation; in addition, this structure can also compensate for mold size changes caused by thermal expansion, avoid stress concentration, and improve mold life.

[0049] The lower mold 104 also includes a plurality of first heat sinks 123, which are fixed to the outside of the lower mold body 119.

[0050] Multiple first heat sinks 123 are uniformly and densely fixed to the outer side wall of the lower mold body 119, and can be installed by means of integral casting, welding, or screw fastening. The heat sinks have a plate-like or fin-like structure and extend along the circumferential or vertical direction of the lower mold body 119, significantly increasing the contact area between the lower mold body 119 and the surrounding air. After casting is completed, the casting releases a large amount of heat during solidification. This heat is conducted through the lower mold body 119 to the surface of the first heat sinks 123, accelerating the dissipation of heat into the environment under natural convection or assisted air cooling conditions.

[0051] The air-cooling assembly also includes an auxiliary blade group, which is disposed on one side of the drive shaft 110.

[0052] The auxiliary blade assembly includes a driving gear 124, a driven gear 125, a driven rod 126, and a driven blade 127. The driving gear 124 is fixed to the transmission shaft 110. The driven gear 125 meshes with the driving gear 124. The driven rod 126 is connected to the driven gear 125. The driven blade 127 is fixedly connected to the driven rod 126.

[0053] The drive gear 124 is fixedly mounted on the extended section of the transmission shaft 110, and is typically circumferentially fixed using a key connection or interference fit to ensure that it can rotate synchronously with the transmission shaft 110. The drive gear 124 is made of high-strength wear-resistant metal material (such as alloy steel or carburized steel) and undergoes precision machining and heat treatment, possessing good transmission accuracy and fatigue resistance.

[0054] Driven gear 125 meshes with driving gear 124, and its tooth profile precisely matches that of driving gear 124 to ensure smooth transmission, low noise, and no jamming. One or more driven gears 125 can be provided, arranged symmetrically or linearly to achieve multi-point airflow disturbance. When drive shaft 110 drives driving gear 124 to rotate, power is transmitted to driven gear 125 through gear meshing, causing it to rotate in the opposite direction (or in the same direction, depending on the gear layout).

[0055] The driven rod 126 is a slender drive shaft 110, one end of which is fixedly connected to the center hole of the driven gear 125, and the other end extends upward and passes through a support bracket or mounting plate, maintaining a vertical or inclined arrangement. The specific angle can be optimized according to the airflow guidance requirements. The driven rod 126 is made of rigid material to ensure that it does not bend or vibrate during rotation.

[0056] The driven blade 127 is fixedly connected to the top of the driven rod 126 and is typically made of lightweight, heat-resistant materials (such as aluminum alloy or engineering plastics). Its shape can be propeller-like, fan-like, or twisted airfoil to maximize airflow propulsion efficiency. When the driven gear 125 rotates, it drives the driven rod 126 and the driven blade 127 to rotate synchronously, agitating the cooling water flow outside the mold and promoting thorough mixing and exchange of hot and cold liquids.

[0057] The water-cooled box 112 includes a box body 128, a contact baffle 129, and a nozzle 130. The contact baffle 129 is disposed inside the box body 128 and close to the lower mold body 119, and the nozzle 130 is disposed on the contact baffle 129.

[0058] The housing 128 is the main structure of the water-cooled box 112. It is made of a corrosion-resistant and thermally conductive metal material (such as stainless steel or aluminum alloy), and is hollow inside to store coolant (such as deionized water or special coolant). The housing 128 is fixedly installed on the base 101 and located directly below the lower mold 104. Its top is tightly fitted to the bottom of the lower mold body 119 or has a small gap to form a good heat conduction path.

[0059] Inside the housing 128, a contact baffle 129 is provided, located on the upper part of the housing 128 and close to the bottom surface of the lower mold body 119. Spray nozzles 130 are evenly distributed on the surface of the contact baffle 129 or at the outlet of its internal channels. The number can be set to multiple nozzles, arranged in an array or ring, depending on the cooling requirements. The spray nozzles 130 have an atomizing or fan-shaped nozzle structure and are connected to a circulating pump 114 via pipes. Under high pressure, they spray coolant onto the surface of the contact baffle 129 in the form of a fine water mist or a high-speed liquid stream. This spray cooling method greatly increases the contact area and heat transfer coefficient between the coolant and the hot surface, significantly improving instantaneous cooling capacity, and is especially suitable for rapid cooling of castings in the high-temperature stage immediately after pouring.

[0060] The water-cooled box 112 also includes a reflux spiral tube 131, an absorption chamber 132, an exhaust pipe 133, and a vent valve 134. The reflux spiral tube 131 is connected to the box body 128 and the absorption chamber 132. The exhaust pipe 133 is located at the top of the absorption chamber 132. The vent valve 134 is located on one side of the exhaust pipe 133. The absorption chamber 132 is connected to the liquid circulation channel 113.

[0061] After absorbing heat, the coolant's temperature rises, and some of it may vaporize to form water vapor, which then flows into the return spiral tube 131. One end of the return spiral tube 131 is connected to the housing 128 to collect the mixture of high-temperature coolant and vapor, while the other end extends into the absorption chamber 132. The return spiral tube 131 adopts a spiral coil structure, which has a long flow path and a large specific surface area. Its tube wall contacts the low-temperature coolant or heat dissipation structure in the absorption chamber 132, forming an internal heat exchange. This allows the high-temperature fluid to be pre-cooled before entering the absorption chamber 132, improving the overall thermal efficiency of the system.

[0062] The absorption chamber 132 is an independently installed sealed chamber connected to the liquid circulation channel 113, forming a key node in the coolant circulation loop. Its function is to receive the high-temperature coolant from the return spiral tube 131 and mix it with the low-temperature coolant in the main circulation system. The absorption chamber 132 is equipped with baffles or guide channels to promote uniform mixing of the hot and cold liquids and prevent localized overheating from affecting the operation of the circulation pump 114.

[0063] An exhaust pipe 133 is provided at the top of the absorption chamber 132 to discharge water vapor and other non-condensable gases generated during the cooling process. This is because the cooling system may generate bubbles or release dissolved gases due to high temperatures during long-term operation.

[0064] A vent valve 134 is provided on one side of the vent pipe 133. The vent valve 134 is a one-way valve structure that can be automatically or manually controlled. A pressure threshold can be set. When the gas pressure in the absorption chamber 132 exceeds the safe range, the vent valve 134 will automatically open to discharge excess gas out of the system. After the pressure returns to normal, it will automatically close to ensure that the system is always within the safe pressure range.

[0065] The water-cooled box 112 also includes a plurality of second heat sinks 135, which are disposed on the absorption cavity 132.

[0066] The second heat sink 135 is fixedly mounted on the outer wall of the absorption cavity 132. It is typically made of a high thermal conductivity material such as aluminum or copper and is arranged in a fin-like or columnar shape, significantly increasing the contact area between the absorption cavity 132 and the outside air. Under natural convection or air-cooled conditions, the second heat sink 135 can continuously dissipate some of the heat from the mixture in the absorption cavity 132 into the environment, playing a pre-cooling role, further reducing the temperature of the coolant before entering the circulating pump 114, and improving the heat load capacity of the entire water cooling system.

[0067] Second Embodiment The present invention also provides a method for casting ductile iron for automobiles, using the aforementioned casting apparatus for ductile iron for automobiles.

[0068] Before casting begins, the surfaces of the cavities of the upper mold body 118 and the lower mold body 119 are first cleaned to remove residual oxide scale, release agent residue, and impurities, ensuring the cavities are clean. Then, the mold is preheated using built-in heating elements or an external flame heating device to uniformly raise the mold temperature to the preset temperature. Mold preheating effectively reduces thermal shock when high-temperature molten iron comes into contact with the cold mold.

[0069] The hydraulic system is activated, and the piston rod of the hydraulic cylinder 116 extends downward, driving the drive rod 117 and the upper mold body 118 to smoothly descend along the guide rail on the support frame 102 until the upper mold 103 and the lower mold 104 are completely closed, forming a sealed molding cavity. During the mold closing process, the lower mold body 119 is subjected to pressure at the moment of contact. This pressure is generated by the sliding column 120 compressing the support spring 122 inside the support column 121, producing elastic buffering to prevent damage to the mold caused by rigid collisions. After the mold closing is completed, the system checks whether the mold closing force has reached the set value to ensure reliable mold locking and prevent "mold bulging" or molten metal overflow during the pouring process.

[0070] High-temperature ductile iron molten metal (temperature controlled at 1380–1450℃), after spheroidizing and inoculation treatment, is poured into a closed mold cavity through a sprue cup and runner system. The pouring process employs a constant-flow or stepped pouring method, controlling the pouring speed and flow rate to ensure smooth metal filling and avoid turbulence, air entrapment, and oxide inclusions. During the filling process, mold temperature changes are monitored in real time to provide data support for subsequent cooling control.

[0071] Immediately after casting, the initial cooling stage begins. At this time, the air-cooling assembly is activated: the cooling motor 106 drives the cooling fan 105 to rotate at high speed. External air is drawn in through the intake duct 107, flows through the space above the cavity under the action of the fan, and is discharged through the exhaust duct 108, forming the main airflow channel. Simultaneously, the drive shaft 110 rotates synchronously with the fan, driving the first blade 109 to agitate the intake air. Through the meshing of the drive gear 124 and driven gear 125, it drives the driven rod 126 and driven blade 127 to rotate, enhancing the circulation of the coolant.

[0072] Simultaneously or shortly after the air-cooled start-up, the water-cooling components are activated. The circulation pump 114 begins operation, drawing low-temperature coolant from the water-cooling tank 112 and channeling it through the liquid circulation channel 113 into the pre-embedded cooling channel within the lower mold body 119, absorbing heat conducted from the lower mold 104 and the bottom of the casting. The high-temperature coolant returns to the water-cooling tank 112 and flows into the absorption chamber 132, undergoing pre-cooling via the return spiral tube 131. During this process, the nozzle 130 continuously sprays coolant onto the contact baffle 129, enhancing the heat exchange efficiency between the lower mold 104 and the cooling medium. Water vapor accumulated in the absorption chamber 132 is automatically discharged through the vent pipe 133 and the vent valve 134, preventing air blockage. Simultaneously, multiple second heat sinks 135 located on the outer wall of the absorption chamber 132 and the first heat sink 123 on the outer side of the lower mold body 119 jointly participate in heat dissipation, forming a composite cooling mode of "internal circulation + external natural / forced heat dissipation," achieving efficient and uniform cooling of the bottom and sides of the casting.

[0073] Throughout the cooling process, temperature changes at key points 104 in the upper and lower molds are monitored in real time using temperature sensors. The speed of the air-cooled fan, the water-cooled circulation flow rate, and the spray pressure are dynamically adjusted to achieve "gradient cooling" control. This involves using strong cooling in the initial stage to accelerate solidification, and then appropriately reducing the cooling intensity in the later stages to mitigate the temperature gradient, reduce internal stress, and prevent casting deformation or cracking. This control strategy helps promote sufficient graphite spheroidization and a uniform matrix structure (e.g., controllable ferrite or pearlite ratio), thereby improving the overall performance of the casting.

[0074] Once the casting has completely solidified and cooled to a safe temperature (typically below 800°C), the hydraulic cylinder 116 reverses its direction, causing the piston rod to retract and lifting the upper mold body 118 to complete the mold opening. At this time, the support spring 122 releases its elastic potential energy, pushing the sliding column 120 and the lower mold body 119 slightly upwards to reset, creating a small gap between the casting and the lower mold 104 for easy demolding. Subsequently, a robotic arm or ejection mechanism is used to remove the casting from the lower mold 104 and send it for subsequent heat treatment processes.

[0075] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A casting apparatus for ductile iron used in automobiles, comprising a base, a support frame, an upper mold, and a lower mold, wherein the support frame is fixedly connected to the base and located on one side of the base, the upper mold is slidably disposed on the support frame, and the lower mold is disposed below the upper mold, characterized in that, It also includes an air-cooled assembly and a water-cooled assembly. The air-cooled assembly includes a cooling fan, a cooling motor, an air inlet, an air outlet, a first blade, a drive shaft, and a stirring blade. The air inlet and the air outlet are located on the top of the upper mold. The cooling fan is rotatably located between the air inlet and the air outlet. The output end of the cooling motor is connected to the cooling fan. The first blade is located inside the air inlet. The drive shaft is fixedly connected to the first blade and passes through the air inlet. The stirring blade is connected to the drive shaft. The water-cooling assembly includes a water-cooling tank, a liquid circulation channel, a circulation pump, and a cooler. The water-cooling tank is located below the lower mold and fixed on the base. The liquid circulation channel is connected to the water-cooling tank, the circulation pump is connected to the liquid circulation channel, and the cooler is connected to the circulation pump.

2. The automotive ductile iron casting apparatus as described in claim 1, characterized in that, The upper mold includes a hydraulic cylinder, a drive rod, and an upper mold body. The drive rod is connected to the upper mold body, the hydraulic cylinder is fixed on the support frame, and the output end of the hydraulic cylinder is connected to the drive rod.

3. The automotive ductile iron casting apparatus as described in claim 2, characterized in that, The lower mold includes a lower mold body, a sliding column, a support column, and a support spring. The support column is fixed on the base. The sliding column is slidably connected to the support column and is located on the top of the support column. The lower mold body is fixed on the sliding column. The support spring is disposed between the sliding column and the support column.

4. The automotive ductile iron casting apparatus as described in claim 3, characterized in that, The lower mold also includes a plurality of first heat sinks, which are fixed to the outside of the lower mold body.

5. The automotive ductile iron casting apparatus as described in claim 4, characterized in that, The air-cooling assembly also includes an auxiliary blade group, which is disposed on one side of the drive shaft.

6. The automotive ductile iron casting apparatus as described in claim 5, characterized in that, The auxiliary blade assembly includes a driving gear, a driven gear, a driven rod, and a driven blade. The driving gear is fixed to the transmission shaft, the driven gear meshes with the driving gear, the driven rod is connected to the driven gear, and the driven blade is fixedly connected to the driven rod.

7. The automotive ductile iron casting apparatus as described in claim 6, characterized in that, The water-cooled box includes a box body, a contact baffle, and a nozzle. The contact baffle is disposed inside the box body and close to the lower mold body, and the nozzle is disposed on the contact baffle.

8. The automotive ductile iron casting apparatus as described in claim 7, characterized in that, The water-cooled box also includes a reflux spiral tube, an absorption chamber, an exhaust pipe, and a vent valve. The reflux spiral tube is connected to the box body and the absorption chamber. The exhaust pipe is located at the top of the absorption chamber, and the vent valve is located on one side of the exhaust pipe. The absorption chamber is connected to the liquid circulation channel.

9. The automotive ductile iron casting apparatus as described in claim 8, characterized in that, The water-cooled box also includes a plurality of second heat sinks, which are disposed on the absorption cavity.

10. A method for casting ductile iron for automobiles, characterized in that, The automotive ductile iron casting apparatus described in any one of claims 1 to 9 is used.

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