A Low-Pressure Double-Sided Casting Process for Strengthening Spokes of Truck Wheel Hubs

Abstract

This invention discloses a low-pressure, double-sided casting process for reinforcing the spokes of a truck wheel hub mounting plate. The process involves pressurizing the upper surface of the molten aluminum alloy in the holding furnace via a pressurization control system. This causes the molten aluminum alloy to rise through a riser pipe and enter the casting system from the aluminum molten casting system inlet at the bottom of the mold. The molten aluminum flows through the sprue and runner to separate the slag, then passes through a buffer slag collection bag for a second slag removal and flow stabilization. Finally, it flows through an inlet gate and, through a slag bag level sensor and a mold cavity aluminum molten aluminum filling level sensor, and the pressurization control system, fills the mold cavity of the truck aluminum alloy wheel hub mounting plate spokes and the annular rim area at two different pressurization rates. After pressure holding, the upper and lower mold core water cooling components are simultaneously activated, causing the molten aluminum in the wheel hub mounting plate spoke area to crystallize and solidify into a casting under rapid pressure reduction and cooling. This process results in a denser solidified structure of the molten aluminum in the wheel hub mounting plate spoke area, leading to higher material mechanical properties.

Description

Technical Field

[0001] This invention relates to a truck aluminum alloy wheel hub, and more particularly to a low-pressure double-sided casting process for reinforcing the spokes of a truck wheel hub. Background Technology

[0002] One-piece truck aluminum alloy wheels are typical ring-shaped parts, such as Figure 2 The truck wheel hub is mainly composed of two parts: the mounting disc spokes and the annular rim. The wheel hub is mounted on the brake drum of the axle using mounting disc bolts. It supports the tire, buffers external impacts, ensures tire contact with the ground, and is a crucial safety component for maintaining truck performance. The truck wheel hub bears the entire weight of the vehicle. During truck operation, it transmits the torque output from the gearbox or brake drum during acceleration and deceleration to the tire, subjecting the wheel to alternating loads. The wheel hub mounting disc spokes are subjected to continuous impacts and vibrations; therefore, high fatigue strength is required for the wheel hub mounting disc spokes. Truck aluminum alloy wheels are typically formed using low-pressure casting. The mold used for casting the wheel hub mainly includes an upper mold, a lower mold, and side molds. These molds form the wheel hub cavity, and the pouring port at the center of the lower mold connects to a low-pressure furnace containing molten aluminum. During low-pressure casting, dry compressed air is introduced into the furnace, causing the molten aluminum to enter the wheel hub mold cavity under pressure. The pressure is then maintained for a period of time until the entire wheel hub is filled and completely solidified.

[0003] Currently, aluminum alloy truck wheel hubs produced by low-pressure center casting generally suffer from low mechanical properties at the mounting disc spokes. This is crucially related to the order of aluminum molten filling, cooling rate, and sequential solidification and feeding during the low-pressure casting process. In existing low-pressure center-cast aluminum alloy wheel hubs, the mounting disc spokes are the first point where molten aluminum enters the wheel hub mold cavity. The flow of molten aluminum at the mounting disc spokes only stops when the entire mold cavity is completely filled. During the flow, the molten aluminum continuously heats the surface of the mold cavity at the mounting disc spokes. When the molten aluminum completely fills the mold cavity and stops flowing, the temperature of both the molten aluminum and the mold at the spokes is at its highest. This results in slow cooling of the molten aluminum at the spokes, coarse solidification structure, and low mechanical properties. Furthermore, the prolonged flow of molten aluminum causes oxide scale and other slag on the surface to tumble into the casting, creating fatigue crack initiation points and severely impacting the safety of the truck wheel hub. The spokes of the mounting disc of a truck wheel hub are the points of stress concentration during acceleration, deceleration and steering of a vehicle. When subjected to cyclic torque impact, the spokes of the wheel hub mounting disc are prone to fatigue cracks. Therefore, it is necessary to improve the strength and mechanical properties of the spokes of the truck aluminum alloy wheel hub mounting disc. Summary of the Invention

[0004] This invention addresses the shortcomings of existing truck aluminum alloy wheel hubs, such as the low mechanical properties of the mounting disc spokes, the susceptibility to oxide scale and other impurities during casting, which can lead to internal fatigue crack initiation. This results in fatigue cracks in the mounting disc spokes under cyclic torque impact during truck acceleration or steering, negatively impacting the safety of the truck wheel hub. The invention provides a low-pressure, double-sided casting process for strengthening the mounting disc spokes of truck wheels. This process improves the solidification quality of the molten aluminum in the mounting disc area during casting, eliminates fatigue crack initiation, and results in a denser, more compact aluminum structure in the mounting disc spoke area. Ultimately, this enhances the mechanical properties of the mounting disc spokes, improving product quality and safety.

[0005] The specific technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: a low-pressure double-sided casting mounting plate reinforcement casting process for truck wheel hubs, characterized by the following casting method: after mold closing, dry compressed air is introduced into the holding furnace through the pressurization control system of the low-pressure casting machine to pressurize the upper surface of the aluminum alloy molten liquid in the holding furnace, so that the aluminum alloy molten liquid in the holding furnace rises through the riser pipe and enters the casting system from the aluminum liquid casting system inlet at the lower end of the mold; the aluminum liquid casting system includes an inlet, a sprue, a runner, a buffer slag collection bag, an inlet gate, and a slag bag liquid level sensing device;

[0006] The molten aluminum flows through the sprue and runner to separate the slag, then through the buffer slag collection bag for a second slag removal and flow stabilization, and then through the in-gating gate. It is filled into the mold cavities of the truck aluminum alloy wheel hub casting's mounting disc spokes and annular rim sections at two different pressurization speeds, through a slag bag level sensor, a mold cavity aluminum molten aluminum filling level sensor, and the low-pressure casting machine's pressurization control system. The pressurization speed when filling the mold cavity of the truck aluminum alloy wheel hub casting's mounting disc spokes is lower than the pressurization speed when filling the mold cavity of the truck aluminum alloy wheel hub casting's annular rim section.

[0007] After the molten aluminum fills the mold cavity, the pressure is increased and maintained for a period of time. During the pressure maintenance, the upper mold core water cooling component and the lower mold core water cooling component are turned on, so that the molten aluminum in the mounting plate of the truck wheel hub mold solidifies and crystallizes sequentially from the center towards the junction of the mounting plate and the ring rim under the pressure of the molten aluminum and rapid cooling, forming the casting mounting plate. The ring rim solidifies and crystallizes sequentially from top to bottom, forming the casting ring rim.

[0008] By employing pressurization and combining data from slag level sensors and mold cavity aluminum molten metal filling level sensors in the holding furnace of the low-pressure casting machine, and integrating this data with the low-pressure casting machine's pressurization control system, the aluminum molten metal is controlled to smoothly fill the mold cavity of the wheel hub mounting disc spoke area from the side gaps under its own gravity. During the aluminum molten metal flow, the oxide scale generated by contact with oxygen in the mold cavity remains on the surface of the aluminum molten metal, preventing turbulence caused by external forces from carrying the oxide scale into the casting. This improves the internal quality of the truck wheel hub product. It can improve the crystallization and solidification quality of the aluminum molten metal in the wheel hub mounting disc area during casting and eliminate the generation of fatigue crack initiation sites, resulting in a denser solidified structure of the aluminum molten metal in the wheel hub mounting disc spoke area, higher mechanical properties of the wheel hub mounting disc spoke material, and improved product quality and safety. During the aluminum molten flow filling process, there are two different filling methods for the mounting plate spokes and the annular rim. The aluminum molten flow during spoke filling and rim filling do not interfere with each other. Similarly, during solidification, the aluminum molten flow between the mounting plate spokes and the rim also does not interfere with each other. The spoke filling and solidification processes are essentially separate from the rim filling and solidification processes, and they do not interfere with each other. Solidification mainly relies on cooling; the lower the temperature, the faster the solidification. The higher the temperature at the beginning of the flow, the later the solidification; the lower the temperature at the end, the earlier the solidification. Simultaneously, cooling is implemented at the end of the flow to control the earliest possible solidification.

[0009] Preferably, the pressurization control system employs a multi-stage pressurization molding process to control the pressurization pressure and time of the dry compressed air introduced into the heat preservation furnace, including:

[0010] B1. The first stage of pressurization is at a pressure of 240±5 mbar and the pressurization time is 9±2 s;

[0011] B2. The pressure for the second stage of pressurization is 270±5 mbar, and the pressurization time is 2±1 s;

[0012] B3. The third stage of aluminum liquid height maintenance section is pressurized at 310-330 mbar. Based on the detection data from the slag ladle level sensor and the mold cavity aluminum liquid filling level sensor, the aluminum liquid in the casting system is maintained at the height of the top surface of the buffer slag ladle. Under its own gravity, the aluminum liquid smoothly fills the cavity of the wheel hub mold mounting plate spoke section from the gating gates on both sides. When the aluminum liquid completely fills the cavity of the wheel hub mold mounting plate spoke section and the liquid level reaches the installation position of the mold cavity aluminum liquid filling level sensor, the pressurization control system of the low-pressure casting machine pressurizes again according to the fourth stage pressurization setting, so that the aluminum liquid continues to fill the cavity of the truck wheel hub mold annular rim section from bottom to top through the casting system.

[0013] B4. The pressure for the fourth stage is 335±20 mbar, and the pressurization time is 7±2 s;

[0014] B5. The pressure for the fifth stage is 650±15mbar, and the pressurization time is 9±2s;

[0015] B6. The sixth stage pressure is 650±15mbar, and the pressure holding time is 180±10s. After depressurization, wait 45±5s before opening the mold and taking out the casting.

[0016] Preferably, the water-cooling component of the upper mold core starts flowing water 7±2s after the start of pressure holding, lasting for 150 to 160s, with a water flow rate of 300L / min to 350L / min; the water-cooling component of the lower mold core starts flowing water 3±2s after the start of pressure holding, lasting for 150 to 170s, with a water flow rate of 300L / min to 350L / min.

[0017] Preferably, the cooling water temperature of the upper mold core water cooling assembly and the lower mold core water cooling assembly is controlled at 28~33℃, and the cooling water is high-pressure circulating pure water with a pressure preferably of 0.55~0.65MPa.

[0018] Preferably, the temperature of the molten aluminum in the holding furnace is 685–695°C.

[0019] Preferably, the upper mold core controls the surface temperature of the mold cavity to be 150-200°C before the aluminum liquid filling mold cavity; the lower mold core controls the surface temperature of the mold cavity to be 210-230°C before the aluminum liquid filling mold cavity.

[0020] Preferably, the slag level sensor is located on top of the buffer slag bag in the casting system. The buffer slag bag is designed with a gradually decreasing width from top to bottom, and its top is 10-13 mm above the top surface of the runner. The runner is tapered. This allows the molten aluminum entering the casting system to quickly overflow the top surface of the gating gate in the slit, improving the stability of the molten aluminum filling in the slit gating and simultaneously enhancing the slag-floating capacity of the buffer slag bag.

[0021] Preferably, the direct gating channel is a cylinder located at an angle A along the axial direction of the inlet. The direction of liquid flow into the gating channel within the gap is horizontally aligned with the inclined direction of the outer ring of the mounting plate, and the angle A is between 10° and 12°. The flow direction of the molten aluminum, which enters vertically from the inlet, gradually turns towards the horizontal gating channel, which is beneficial for scum removal and slow flow.

[0022] Preferably, the mold cavity aluminum liquid filling level sensing device is located at the junction of the mounting plate spokes and the annular rim corresponding to the side mold of the mold. This improves the stability, reliability, and effectiveness of aluminum liquid filling detection at the junction of the mounting plate spokes and the annular rim, and enhances the crystallization and solidification quality of the aluminum liquid at the mounting plate location.

[0023] Preferably, the aluminum liquid casting system is located at the side mold closing surface of the mold. The aluminum liquid casting system includes a feed inlet, a sprue, a runner, a buffer slag collection bag, an inlet gate, and a slag bag liquid level sensing device. The feed inlet of the aluminum liquid casting system is sealed and connected to one end of the riser pipe in the heat preservation furnace of the low-pressure casting machine. The upper mold core water cooling component is located at the spoke portion of the upper mold corresponding to the hub mounting plate of the mold, and the lower mold core water cooling component is located at the spoke portion of the lower mold corresponding to the hub mounting plate of the mold.

[0024] The beneficial effects of this invention are as follows: The low-pressure double-sided casting process for reinforcing the spokes of a truck wheel hub mounting plate involves a casting system located on the side mold mating surface. The inlet gate is positioned at the junction of the spokes and the annular rim. Molten aluminum fills the cavity of the spokes first, then the cavity of the annular rim. As the molten aluminum continues to flow upwards to fill the cavity of the annular rim, the molten aluminum already filled in the spokes remains stationary and does not need to continue flowing. At this point, the upper and lower mold core water-cooling components can be activated for rapid cooling. This allows the molten aluminum in the spokes cavity to rapidly crystallize and solidify from the center outwards. Simultaneously, the molten aluminum at the junction of the spokes and the annular rim fully compensates for shrinkage in the spokes area under pressure, thus improving the quality of the solidification. This results in a denser solidified structure, better material mechanical properties, and superior product quality. It can improve the crystallization and solidification quality of the aluminum liquid in the hub mounting plate area during casting, eliminate the generation of fatigue crack sources, make the aluminum liquid crystallization and solidification structure in the hub mounting plate spoke area more dense, avoid or reduce the hub mounting plate spokes, and improve the material mechanical properties, thereby improving product quality and safety. When the aluminum liquid flows through the mold, there are two different pressurization speeds for filling the mounting plate spokes and the annular rim. The flow of aluminum liquid does not interfere with each other when filling the spokes and the rim. When the aluminum liquid solidifies, the aluminum liquid in the mounting plate spokes and the rim also does not interfere with each other. Attached Figure Description

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0026] Figure 1 This is a schematic diagram of the wheel hub mold structure involved in the low-pressure double-sided casting and mounting plate reinforcing casting process of the truck wheel hub of the present invention.

[0027] Figure 2 This is a schematic diagram of the existing technology for casting aluminum alloy wheel hubs using center casting.

[0028] Figure 3 This is a schematic diagram of the low-pressure double-sided casting aluminum alloy wheel hub of the present invention;

[0029] Figure 4This is a pressure-pressurizing and pressure-holding process curve of the low-pressure double-sided casting mounting plate reinforcing casting process of the truck wheel hub of the present invention.

[0030] Among them: 1-truck wheel hub casting, 2-casting gate, 3-ring rim, 4-junction of mounting disc spoke and ring rim, 5-mounting disc spoke, 6-first casting gate, 7-second casting gate, 8-sprue, 9-glide, 10-slag buffer bag, 11-in-gating gate, 12-upper mold, 13-side mold, 14-molded aluminum liquid filling level sensor for mold cavity, 15-lower mold, 16-upper mold core, 17-lower mold core, 18-upper mold core water cooling assembly, 19-lower mold core water cooling assembly, 20-slag bag level sensor. Detailed Implementation

[0031] Figure 1 , Figure 3 , Figure 4 In the illustrated embodiment, a low-pressure double-sided casting process for reinforcing the spokes of a truck wheel hub includes the following casting method:

[0032] After mold closing, the pressure control system of the low-pressure casting machine introduces dry compressed air into the holding furnace to pressurize the upper surface of the molten aluminum alloy inside the furnace. This causes the molten aluminum alloy in the holding furnace to rise through the riser pipe and enter the casting system from the aluminum liquid casting system inlet at the bottom of the mold. The aluminum liquid casting system includes an inlet, a sprue, a runner, a buffer slag collection bag, an inlet gate, and a slag bag level sensor. The sprue is a cylinder located at an angle A (10°≤A≤12°) along the axial direction of the inlet. The runner is converging, and the flow direction of the liquid entering through the inlet gate is horizontally aligned with the inclination direction of the outer ring of the mounting plate. The slag bag level sensor is located on top of the buffer slag bag in the casting system. The buffer slag bag is designed as an inverted pear shape with its width gradually decreasing from top to bottom, and the top of the buffer slag bag is 10-13 mm higher than the top surface of the runner.

[0033] The molten aluminum flows through the sprue and runner, where it is diverted to remove slag. After a second slag removal and flow stabilization process using a buffer slag collection bag, it then flows through an inlet gate. The molten aluminum is then filled into the mold cavities of the truck aluminum alloy wheel hub casting's mounting disc spokes and annular rim sections at two different pressurization rates, controlled by a slag bag level sensor, a mold cavity aluminum molten aluminum filling level sensor, and the low-pressure casting machine's pressurization control system. The pressurization rate for filling the mold cavity of the truck aluminum alloy wheel hub casting's mounting disc spokes is lower than the pressurization rate for filling the mold cavity of the truck aluminum alloy wheel hub casting's annular rim section.

[0034] After holding the pressure for a period of time, the holding time can be between 170 and 190 seconds. Simultaneously, the upper and lower mold core water cooling components are activated, allowing the molten aluminum in the spoke portion of the truck wheel hub mold mounting plate to crystallize and solidify into a casting under pressure and rapid cooling. Rapid cooling with circulating water via the upper and lower mold core water cooling components ensures that the molten aluminum in the spoke portion of the truck wheel hub mold mounting plate solidifies and crystallizes sequentially from the center towards the junction of the mounting plate spoke and the annular rim, forming the cast mounting plate spoke. The annular rim solidifies and crystallizes sequentially from top to bottom, forming the cast annular rim.

[0035] Forced cooling is applied to the water cooling components of the upper and lower mold cores; after holding the pressure for 180±10s, the pressure is released, and the casting is allowed to cool naturally for 45±5s before opening the mold and removing the casting.

[0036] The truck wheel hub mold involved in the above casting method includes an upper mold 12, an upper mold core 16, a lower mold 15, a lower mold core 17, and a side mold 13. The upper mold 12, upper mold core 17, lower mold 15, lower mold core 17, and side mold 13 form a mold cavity for the truck wheel hub. An aluminum liquid casting system is provided on the mating surface of the side mold 13. The aluminum liquid casting system includes inlets 6 and 7, a sprue 8, a runner 9, a slag catcher 10, an in-gating gate 11, and a slag catcher level sensor 20. The mounting plate 4 corresponding to the side mold 13 (see...) Figure 2 , Figure 3 A mold cavity aluminum liquid filling level sensing device 14 is provided at the junction 4 of the ring rim 2; the aluminum liquid casting system inlet 6 and 7 are sealed to one end of the riser pipe in the low-pressure casting machine holding furnace; the upper mold 12 is provided with an upper mold core water cooling component 18 corresponding to the hub mounting plate spoke 5; the lower mold 15 is provided with a lower mold core water cooling component 19 corresponding to the hub mounting plate spoke 5; the specific process of low-pressure double-sided casting mounting plate spoke reinforcement casting of truck wheel hub is as follows: the mold is closed, and dry compressed air is introduced into the holding furnace through the pressure control system of the low-pressure casting machine. The upper surface of the molten aluminum alloy in the pressurized holding furnace allows it to rise through the riser pipe and enter the casting system from the feed ports 6 and 7 at the bottom of the mold. The molten aluminum flows through the sprue 8 and runner 9 to divert slag, buffers the slag collection bag 10 for a second slag release and stabilizes the flow, and then through the inlet gate 11. It is then filled into the mold cavity of the truck aluminum alloy wheel hub casting mounting disc spoke 5 and the annular rim 3 at two different pressurization speeds by the slag bag level sensor 20, the mold cavity aluminum molten aluminum filling level sensor 14, and the pressurization control system of the low-pressure casting machine. After holding the pressure for a period of time, the upper mold core water cooling assembly 18 and the lower mold core water cooling assembly 19 are simultaneously activated, causing the molten aluminum in the truck wheel hub mold mounting disc spoke 5 to crystallize and solidify into a casting under pressure and rapid cooling.

[0037] The pressurization control system uses a multi-stage pressurization molding process to control the pressurization pressure and time of the dry compressed air supplied to the heat preservation furnace. The multi-stage pressurization molding process includes:

[0038] B1. The first stage of pressurization is at a pressure of 240±5 mbar and the pressurization time is 9±2 s;

[0039] B2. The pressure for the second stage of pressurization is 270±5 mbar, and the pressurization time is 2±1 s;

[0040] B3. The third stage of aluminum liquid height maintenance stage is pressurized at 310-330 mbar. Based on the detection data of the slag ladle liquid level sensor and the mold cavity aluminum liquid filling liquid level sensor, the aluminum liquid in the casting system is kept at the height of the top surface of the buffer slag ladle. Under its own gravity, the aluminum liquid smoothly fills the cavity of the wheel hub mold mounting plate spoke part from the gating gates on both sides. When the aluminum liquid completely fills the cavity of the wheel hub mold mounting plate spoke part and the liquid level reaches the installation position of the mold cavity aluminum liquid filling liquid level sensor, the pressurization control system of the low-pressure casting machine pressurizes again according to the fourth stage pressurization setting, so that the aluminum liquid continues to fill the cavity of the truck wheel hub mold ring rim part from bottom to top through the casting system.

[0041] B4. The pressure for the fourth stage is 335±20 mbar, and the pressurization time is 7±2 s;

[0042] B5. The pressure for the fifth stage is 650±15mbar, and the pressurization time is 9±2s;

[0043] B6. The sixth stage pressure is 650±15mbar, and the pressure holding time is 180±10s. After depressurization, wait 45±5s before opening the mold and taking out the casting.

[0044] The water cooling system of the upper mold core is set to start flowing water 7±2 seconds after the start of pressure holding, lasting for 150-160 seconds, with a water flow rate of 300-350 L / min. The water cooling system of the lower mold core is set to start flowing water 3±2 seconds after the start of pressure holding, lasting for 150-170 seconds, with a water flow rate of 300-350 L / min. The cooling water temperature of both the upper and lower mold core water cooling systems is controlled at 28-33℃, and the cooling water is high-pressure circulating pure water, preferably at a pressure of 0.55-0.65 MPa. The aluminum liquid temperature in the holding furnace is preferably 685-695℃. The surface temperature of the upper mold core cavity is controlled at 150-200℃ before the aluminum liquid fills the mold cavity. The surface temperature of the lower mold core cavity is controlled at 210-230℃ before the aluminum liquid fills the mold cavity. The aluminum molten metal filling level sensor for the mold cavity is located at the junction of the mounting plate and the annular rim on the side mold. The aluminum molten metal casting system is located at the mold's side mold mating surface. The aluminum molten metal casting system includes a feed inlet, sprue, runner, buffer slag collection bag, in-gating gate, and slag bag level sensor. The feed inlet of the aluminum molten metal casting system is sealed to one end of the riser pipe inside the low-pressure casting machine's holding furnace. The upper mold core water cooling assembly is located at the hub mounting plate corresponding to the upper mold, and the lower mold core water cooling assembly is located at the hub mounting plate corresponding to the lower mold.

[0045] This invention relates to a low-pressure, double-sided casting process for reinforcing the spokes of a truck wheel hub. It employs a pressurized (cd) section in the holding furnace of the low-pressure casting machine to maintain the aluminum melt height. This is combined with data from a slag level sensor 20 and a mold cavity aluminum melt filling level sensor 4, all integrated with the low-pressure casting machine's pressurization control system to control the aluminum melt filling. This allows the aluminum melt to smoothly fill the cavity of the spokes 5 of the wheel hub mold through the gating gates 11 on both sides under its own gravity. During the aluminum melt's flow, the oxide scale generated from contact with oxygen in the mold cavity remains on the surface, preventing turbulence caused by external forces from carrying the oxide scale into the casting. This improves the internal quality of the truck wheel hub product.

[0046] Figure 4 As shown: Section ab is pressurized when the molten aluminum rises in the riser pipe; Section bc is pressurized when the molten aluminum enters the casting system through the inlet of the molten aluminum casting system; Section cd is pressurized when the molten aluminum fills the mold cavity at the part of the truck clutch wheel hub where the disc and spokes are gradually installed; Section de is pressurized when the molten aluminum fills the mold cavity at the part of the truck aluminum alloy wheel hub casting where the annular rim is; Section ef is pressurized and cooled after the molten aluminum fills the mold cavity; Section fg is pressurized and cooled after the molten aluminum fills the mold cavity; and Section gk is depressurized.

[0047] This invention relates to a low-pressure, double-sided casting process for reinforcing the spokes of a truck wheel hub mounting plate. The casting system is located on the mating surface of the side mold 13, with the inlet gate 11 positioned at the junction 4 of the truck wheel hub mounting plate spokes and the annular rim. Molten aluminum first fills the cavity of the mounting plate spokes 5 in the mold, and then fills the cavity of the annular rim 3. While the molten aluminum continues to flow and fill the cavity of the annular rim 3, the molten aluminum already filled at the mounting plate spokes 5 remains stationary and does not need to continue flowing. At this point, the upper mold core water-cooling assembly 18 and the lower mold core water-cooling assembly 19 can be activated for rapid cooling with circulating water. This allows the molten aluminum in the cavity of the mounting plate spokes 5 to rapidly crystallize and solidify from the center outwards. Simultaneously, the molten aluminum at the junction 4 of the truck wheel hub mounting plate spokes 5 and the annular rim 3 effectively compensates for shrinkage at the mounting plate spokes 5, thus improving the quality of crystallization and solidification at the mounting plate spokes 5. This results in a denser solidified structure of the molten aluminum at the mounting plate spokes 5, better material mechanical properties, and superior product quality.

[0048] In the description of positional relationships in this invention, terms such as "inner," "outer," "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing embodiments 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. Therefore, they should not be construed as limitations on this invention.

[0049] The above content and structure describe the basic principles, main features, and advantages of the product of this invention, which should be understood by those skilled in the art. The examples and descriptions above are merely illustrative of the principles of this invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A low-pressure double-sided casting process for reinforcing the spokes of a truck wheel hub, characterized in that... Including the following casting methods: After the mold is closed, the pressure control system of the low-pressure casting machine introduces dry compressed air into the holding furnace to pressurize the upper surface of the aluminum alloy melt in the holding furnace. This causes the aluminum alloy melt in the holding furnace to rise through the riser pipe and enter the casting system from the aluminum liquid casting system inlet at the bottom of the mold. The aluminum liquid casting system includes the inlet, sprue, runner, buffer slag collection bag, in-gating gate, and slag bag liquid level sensor. The molten aluminum flows through the sprue and runner to separate the slag, then through the buffer slag collection bag for a second slag removal and flow stabilization, and then through the in-gating gate. It is filled into the mold cavities of the truck aluminum alloy wheel hub casting's mounting disc spokes and annular rim sections at two different pressurization speeds, through a slag bag level sensor, a mold cavity aluminum molten aluminum filling level sensor, and the low-pressure casting machine's pressurization control system. The pressurization speed when filling the mold cavity of the truck aluminum alloy wheel hub casting's mounting disc spokes is lower than the pressurization speed when filling the mold cavity of the truck aluminum alloy wheel hub casting's annular rim section. After the aluminum liquid fills the mold cavity, the pressure is increased and held for a period of time. During the pressure holding period, the upper mold core water cooling component and the lower mold core water cooling component are turned on, so that the aluminum liquid in the part of the truck wheel hub mold mounting plate spoke plate solidifies and crystallizes sequentially from the center to the junction of the mounting plate spoke plate and the ring rim under the pressure of the aluminum liquid and rapid cooling, forming the casting mounting plate spoke plate. The ring rim solidifies and crystallizes sequentially from top to bottom, forming the casting ring rim. The casting system is located on the side mold closing surface, and the in-gating gate is located at the junction of the truck wheel hub mounting plate spokes and the annular rim. The molten aluminum first fills the cavity of the mold mounting plate spokes and then fills the cavity of the annular rim. When the molten aluminum continues to flow from bottom to top to fill the cavity of the annular rim, the molten aluminum that has already filled the mounting plate spokes remains stationary and does not need to continue flowing. At this time, the upper mold core water cooling components and the lower mold core water cooling components can be turned on for rapid cooling with circulating water. This allows the molten aluminum in the cavity of the mold mounting plate spokes to crystallize and solidify rapidly from the center to the periphery. At the same time, the molten aluminum at the junction of the truck wheel hub mounting plate spokes and the annular rim fully compensates for the shrinkage of the mounting plate spokes under pressure, thus improving the crystallization and solidification quality of the molten aluminum in the mounting plate area.

2. The low-pressure double-sided casting process for reinforcing the spokes of a truck wheel hub according to claim 1, characterized in that... The aforementioned pressurization control system employs a multi-stage pressurization molding process to regulate the pressurization pressure and time of the dry compressed air supplied to the heat preservation furnace, including: B1. The first stage of pressurization is at a pressure of 240±5 mbar and the pressurization time is 9±2 s; B2. The pressure for the second stage of pressurization is 270±5 mbar, and the pressurization time is 2±1 s; B3. The third stage of aluminum liquid height maintenance stage is pressurized at 310-330 mbar. Based on the detection data of the slag ladle liquid level sensor and the mold cavity aluminum liquid filling liquid level sensor, the aluminum liquid in the casting system is kept at the height of the top surface of the buffer slag ladle. Under its own gravity, the aluminum liquid smoothly fills the cavity of the wheel hub mold mounting plate spoke part from the gating gates on both sides. When the aluminum liquid completely fills the cavity of the wheel hub mold mounting plate spoke part and the liquid level reaches the installation position of the mold cavity aluminum liquid filling liquid level sensor, the pressurization control system of the low-pressure casting machine pressurizes again according to the fourth stage pressurization setting, so that the aluminum liquid continues to fill the cavity of the truck wheel hub mold ring rim part from bottom to top through the casting system. B4. The pressure for the fourth stage is 335±20 mbar, and the pressurization time is 7±2 s; B5. The pressure for the fifth stage is 650±15mbar, and the pressurization time is 9±2s; B6. The sixth stage pressure is 650±15mbar, and the pressure holding time is 180±10s. After depressurization, wait 45±5s before opening the mold and taking out the casting.

3. The low-pressure double-sided casting process for reinforcing the spokes of a truck wheel hub according to claim 1, characterized in that... The water cooling assembly for the upper mold core is set to start water flow 7±2s after the start of pressure holding, and continue for 150 to 160s, with a water flow rate of 300L / min to 350L / min. The water cooling assembly for the lower mold core is set to start water flow 3±2s after the start of pressure holding, and last for 150 to 170s, with a water flow rate of 300L / min to 350L / min.

4. The low-pressure double-sided casting process for reinforcing the spokes of a truck wheel hub according to claim 1 or 3, characterized in that... The cooling water temperature of the upper mold core water cooling assembly and the lower mold core water cooling assembly is controlled at 28~33℃, and the cooling water is high-pressure circulating pure water with a pressure of 0.55~0.65MPa.

5. The low-pressure double-sided casting process for reinforcing the spokes of a truck wheel hub according to claim 1, characterized in that... The temperature of the molten aluminum in the heat preservation furnace is 685-695℃.

6. The low-pressure double-sided casting process for reinforcing the spokes of a truck wheel hub according to claim 1, characterized in that... The upper mold core controls the surface temperature of the mold cavity to be 150-200℃ before the aluminum liquid filling mold cavity; the lower mold core controls the surface temperature of the mold cavity to be 210-230℃ before the aluminum liquid filling mold cavity.

7. The low-pressure double-sided casting process for reinforcing the spokes of a truck wheel hub according to claim 1, characterized in that... The slag bag level sensing device is installed on top of the buffer slag bag in the casting system. The buffer slag bag is designed with a structure in which the width gradually decreases from top to bottom. The top of the buffer slag bag is 10-13 mm higher than the top surface of the horizontal runner. The horizontal runner is converging in shape.

8. The low-pressure double-sided casting process for reinforcing the spokes of a truck wheel hub according to claim 1, characterized in that... The sprue is a cylindrical structure located at an angle A along the axial direction of the inlet. The direction of liquid flow into the sprue is horizontally aligned with the inclination direction of the outer ring of the mounting plate. The angle A is between 10° and 12°.

9. The low-pressure double-sided casting process for reinforcing the spokes of a truck wheel hub according to claim 1, characterized in that... The mold cavity aluminum liquid filling level sensing device is located at the junction of the mounting plate and the annular rim corresponding to the side mold of the mold.

10. The low-pressure double-sided casting process for reinforcing the spokes of a truck wheel hub according to claim 1, characterized in that... The aluminum liquid casting system is located at the side mold closing surface of the mold. The aluminum liquid casting system includes a feed inlet, a sprue, a runner, a buffer slag collection bag, an inlet gate, and a slag bag liquid level sensing device. The feed inlet of the aluminum liquid casting system is sealed and connected to one end of the riser pipe in the heat preservation furnace of the low-pressure casting machine. The upper mold core water cooling component is located at the spoke part of the upper mold corresponding to the hub mounting plate of the mold, and the lower mold core water cooling component is located at the spoke part of the lower mold corresponding to the hub mounting plate of the mold.

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