Wheel casting apparatus and method based on multi-gating with tire bead seat

Abstract

This invention relates to the field of anti-gravity casting technology, specifically disclosing a wheel casting molding equipment and method based on multi-gate filling of the outer tire bead seat, including a holding furnace, a riser pipe, a mold, and a pressure system. By controlling the pressure system, molten metal rises through the riser pipe and enters the mold. The riser pipe is connected to a pouring cup at the top, and the molten metal is poured into the runner through a pouring structure. The runner is located at the outer tire bead seat, surrounds the wheel, and is connected to the mold cavity. The molten metal is poured horizontally. The pouring structure includes four pouring channels of three different structures, with each of the four pouring channels having an included angle of 90°. Using this invention to cast large-size aluminum alloy wheels results in stable filling, significantly shortens the feeding distance, controls casting defects such as shrinkage cavities and porosity, and significantly improves the casting quality and mechanical properties of large-size aluminum alloy wheels.

Description

Technical Field

[0001] This invention relates to the field of anti-gravity casting technology, and in particular to wheel casting equipment and methods based on multi-gate filling of the tire bead seat. Background Technology

[0002] Anti-gravity casting is a casting process developed in the 1950s. It involves filling a mold cavity with molten metal from bottom to top under pressure, overcoming gravity and other resistance, and then solidifying under pressure. Depending on the form of pressure applied during the filling of the mold, anti-gravity casting can be classified into low-pressure casting, differential pressure casting, pressure-adjusting casting, and vacuum casting.

[0003] Traditional aluminum alloy wheels typically employ low-pressure casting technology with a single-riser tube filling. This involves placing a riser tube at the center of the wheel (the wheel core) to allow molten metal to enter the mold cavity and complete filling and solidification. While simple in design and easy to implement, this method suffers from drawbacks such as long filling distances, difficult molding, and mold temperatures exceeding 400°C to avoid cold shuts. This results in slow cooling rates, coarse microstructure, and a tendency for casting defects like shrinkage cavities and porosity at hot spots. To refine the microstructure and eliminate these defects, existing technologies generally employ water cooling or water mist cooling to enhance mold cooling. However, while enhanced cooling significantly shortens solidification time (e.g., reducing solidification time to less than 100 seconds for large wheels), it also creates difficulties in controlling the temperature field during cooling and solidification. This leads to challenges in achieving sequential solidification, unstable product performance, and a tendency for localized shrinkage cavities and porosity defects, resulting in low yield rates.

[0004] CN103551545A and CN104550843B disclose a method combining a central gate and two side gates, aiming to reduce the weight of the wheel hub and improve its mechanical strength. CN212761058U discloses a multi-gate wheel casting molding equipment, in which a melt holding furnace connected to a gas source is provided with multiple riser pipes. The riser pipes are connected to the mold gate through a heat preservation cup and a gate sleeve. The lower part of the riser pipes is immersed in the molten metal. When the molten metal in the furnace is pressurized by gas pressure, the melt can rise along the multiple riser pipes and enter the mold cavity through the gate. The mold gate is set on the annular surface directly below the wheel rim.

[0005] However, the aforementioned devices and methods also have significant drawbacks. For the method where molten aluminum enters only from the rim, the inlet is located in the middle of the rim. This causes flow splitting, meaning the molten aluminum simultaneously fills both the core and the rim, making the filling time uncontrollable at each location. Consequently, the solidification sequence becomes uncontrollable, easily leading to shrinkage cavities and porosity defects. Furthermore, for the method using a combination of a center gate and two side gates, the molten aluminum enters from two inlets, creating a confluence in the middle, which can easily cause breakage due to factors such as poor gas drainage. As for the technical solution of setting the gate on the annular surface directly below the wheel rim, i.e., the bottom surface of the outer rim, firstly, the area that the gate can correspond to is limited due to the width of the bottom surface of the outer rim, which affects the solidification and feeding effect. Secondly, the gate cross-section cannot be expanded, that is, the gate feeding area is limited, which is not suitable for large-size wheels or designs where the spokes and the outer rim intersect at intervals around the circumference. Finally, because the wheel product design has extremely high strength requirements for the annular surface directly below the rim, the microstructure requirements such as the spacing of secondary dendrite walls are strict. If the mold is filled at this location, the solidification speed is slow because a cooling system cannot be arranged there. After solidification, it is difficult to achieve the required performance indicators, which seriously affects the performance of the wheel. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the present invention provides wheel casting molding equipment and method based on multi-gate filling of outer tire bead seat.

[0007] The complete technical solution of this invention includes: A wheel casting molding equipment based on a multi-gating mold for tire bead seats includes: a holding furnace, a riser pipe, a mold, and a pressure system. The holding furnace stores molten metal and keeps it at a constant temperature. The mold has a cavity for the molten metal to solidify. The riser pipe is located below the holding furnace and connected to a pouring cup above it. By controlling the pressure system, the molten metal is forced through the riser pipe and into the mold cavity via the pouring cup. The molten metal is poured into the runner through the sprue cup and the gating structure, and then into the mold cavity. The runner is located at the position of the tire bead seat of the wheel, surrounds the wheel, and is connected to the mold cavity. The molten metal rises vertically in the riser pipe and the sprue cup, turns into a horizontal flow in the gating structure, and is poured horizontally into the runner and the mold cavity. The gating structure includes a first gating channel, a second gating channel, and two third gating channels. The included angle between two adjacent gating channels is 90°, and each includes a gate connected to the runner.

[0008] Furthermore, the first pouring channel is directly opposite a spoke, and two third pouring channels are on either side of the first pouring channel, each directly opposite a spoke. The second pouring channel is symmetrically arranged relative to the first pouring channel, that is, the included angle between the second pouring channel and the first pouring channel is 180°, and the second pouring channel is located in the middle of the two spokes.

[0009] Furthermore, the first pouring channel is responsible for filling and pouring one spoke, the two third pouring channels are each responsible for filling and pouring one spoke, and the second pouring channel is responsible for filling and pouring two spokes.

[0010] Furthermore, each pouring channel includes an initial pouring zone and an extended pouring zone located between the initial pouring zone and the runner.

[0011] Furthermore, the top view of the initial pouring area is semi-circular.

[0012] Furthermore, the wheel casting equipment also includes a cooling system.

[0013] Furthermore, the cooling system enables the sequential solidification process during wheel molding to include four directions: from the uppermost inner rim to the gate, from the middle of the spokes to the gate, from the middle of the spokes to the center riser, and from the lowermost outer rim to the gate.

[0014] Furthermore, the effective flow area and profile characteristics of the first, second, and third pouring channels are determined based on the molten metal filling flow conditions.

[0015] Furthermore, the wheel casting molding method using the aforementioned wheel casting molding equipment includes a liquid raising stage, a mold filling stage, a shell forming stage, a pressure increasing, extrusion and pressure holding stage, and a pressure release and venting stage.

[0016] Furthermore, during the filling stage, the filling speed of the molten metal should not exceed 0.5 m / s.

[0017] Furthermore, during the filling stage, the temperature of the molten metal front end is not lower than 616℃.

[0018] The advantages of this invention over the prior art are: 1. By setting multiple gates at the outer bead seat position, the feeding distance of the casting during the casting process is shortened, the feeding gradient is improved, and the overall mechanical properties of large-size wheels are enhanced. Existing wheels use a scheme with multiple gates on the outer side, in which the molten metal enters the cavity vertically or obliquely. Due to the abrupt change in area, the flow pattern changes abruptly, which easily leads to splashing, turbulence, gas entrapment, and oxide inclusions. In addition, the local flow velocity is too fast, the temperature field is uneven, and it is easy to cause local structural abnormalities, cold shuts, and flow marks. To address the above problems, this invention creatively uses a pouring channel to change the flow of molten metal from vertical to horizontal into the outer bead seat position. This channel connects the gate, the runner, and the outer bead seat cavity. The molten metal rises vertically in the gate, and after entering the horizontal pouring channel, the flow direction changes from vertical to horizontal, entering the cavity circumferentially along the runner in a horizontal laminar flow state. It achieves smooth, uniform, and synchronous liquid injection along the circumference of the outer tire bead seat, which not only increases the liquid injection area but also reduces the metal liquid velocity and makes the filling process more stable. It effectively avoids direct liquid flow, turbulence, air entrapment, and oxidation inclusions, significantly improving the filling stability and solving the problem of secondary oxidation inclusions caused by air entrapment during the filling process.

[0019] 2. For the structural characteristics of asymmetrical wheels (such as five-spoke wheels), the casting structure components were specifically designed. Four casting channels with three different structures were employed, each responsible for casting a single or two spokes. The relevant dimensional parameters of the casting channels for each structure were designed. Furthermore, to address the issue of varying heat transfer due to the different heat dissipation areas of the casting channels, the double-spoke casting channel was insulated. During the filling process, to address the issue of different flow rates of the molten metal as it flows into the casting channels due to the significant difference in the actual flow area between single and double-spoke channels, a safe flow rate was designed, and a targeted local pressure acceleration adjustment method was implemented to ensure smooth and rapid filling, avoiding air entrapment, turbulence, and casting defects.

[0020] 3. Traditional casting processes using a single gate at the wheel core theoretically aim to achieve unidirectional solidification from the inner rim to the gate to ensure feeding. However, for large wheels exceeding 18 inches, the thinner wall of the rim and the longer filling distance cause the temperature at the leading edge of the molten metal to drop rapidly as it fills the thin-walled rim. To prevent premature solidification at the thin-walled area, leading to cold shuts or incomplete filling, the aluminum filling temperature must be significantly increased. However, the long-distance flow of high-temperature molten aluminum results in coarse grains in the casting, significantly reducing its mechanical properties. Furthermore, the traditional single-gate process has only one main feeding channel (from the wheel core to the rim), causing isolated hot spots to easily form in areas far from the gate on large wheels (such as the lower rim and thick spokes). Once the thin-walled section in the middle solidifies first, closing the channel, the distant hot spots lose their feeding source, easily leading to concentrated shrinkage cavities and porosity defects. This invention innovatively combines mold cooling processes (spot cooling, water-cooled blocks, circular water cooling, cooling pipes, etc.) to redesign the traditional single solidification path into four directions, reducing the effective solidification and feeding distance of all areas by more than half. Areas such as the outer rim, which were originally far away, are now within the coverage of the shorter feeding channels, fundamentally eliminating hot spots at the far end and avoiding the generation of concentrated shrinkage cavities and porosity defects.

[0021] 4. The temperature of the molten metal during the initial filling stage remained above 616℃, eliminating the risk of incomplete filling due to excessively low temperatures. The filling speed remained below 0.5m / s throughout the process, resulting in smooth filling without turbulence. The mold's maximum temperature was ≤520℃, with no overheated areas. Solidification proceeded according to the designed sequence, without significant isolated liquid phase regions, eliminating shrinkage defects. The final solidified bead seat had a secondary dendrite arm spacing of 31–54μm, ensuring high mechanical properties. Attached Figure Description

[0022] Figure 1 This is a cross-sectional structural diagram of the wheel formed according to the present invention.

[0023] Figure 2 A three-dimensional view of the cast structure for a wheel.

[0024] Figure 3 A cross-sectional view of the cast structure for the wheel.

[0025] Figure 4 A top view of the cast wheel structure.

[0026] In the diagram: 1-Wheel core, 2-Center hole, 3-Helical hole, 4-Wheel spoke, 5-Inner rim, 6-Inner tube bead seat, 7-Wheel rim, 8-Wheel neck, 9-Outer tube bead seat, 10-Outer rim, 11-Lift pipe, 12-Pour cup, 13-Pouring structure, 14-Riser, 15-Grant, 16-First pouring channel, 17-Second pouring channel, 18-Third pouring channel. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 1 The diagram shown is a cross-sectional structure of the wheel formed by the present invention, including a wheel core 1 located at the center of the wheel, a central hole 2 in the center of the wheel core, a spiral hole 3 for installation on the outer side of the wheel core, and a part on the outer side of the wheel that mates with the tire. The component connecting the wheel core and the part that mates with the wheel is called the spoke 4. The wheel used in the present invention has five spokes, and the gap between the five spokes is called a window.

[0029] In the rim section, among which Figure 1 The highest, first protruding part is called the inner rim 5, which is closer to the inside of the vehicle body when the wheel is installed; the first stepped slope below the inner rim 5 is the inner bead seat 6, which is the mounting surface closer to the inside of the vehicle body when the tire is installed; the part below the inner bead seat 6 is the rim 7, and the part with increased cross-sectional area below the rim 7 is called the wheel neck 8; the third stepped slope below the wheel neck 8 is the outer bead seat 9, which is the mounting surface closer to the outside of the vehicle body when the tire is installed; below the outer bead seat 9... Figure 1 The second protrusion at the lowest point is called the outer rim 10, which is located near the outer side of the vehicle body when the wheel is installed.

[0030] Based on the above wheel structure, this invention discloses a wheel casting molding equipment based on a four-gating mold for the outer tire bead seat. The equipment includes a holding furnace, a riser pipe, a mold, and a pressure system. The holding furnace stores molten metal and keeps it at a constant temperature. The mold has a cavity for the molten metal to solidify and form. Inside the holding furnace, the riser pipe is located below the furnace and is pressurized by gas pressure from the pressure system. Figures 2-3 As shown, the molten metal rises through the riser pipe 11 and enters the mold. The riser pipe 11 is connected to the sprue cup 12 at the top. The sprue cup pours the molten metal into the runner 15 through the gating structure 13. The runner is located at the outer tire bead seat, surrounds the wheel, and is connected to the mold cavity. The molten metal is poured in horizontally. A riser 14 is provided at the wheel core position.

[0031] The above-mentioned filling method is to overcome the problems in the existing technology, such as the flow diversion caused by filling only from the rim, the uncontrollable solidification sequence, the easy breakage caused by the combination of central gate and side gates, the problem of insufficient strength caused by gas discharge, and the problem of insufficient strength caused by filling the annular surface directly below the rim.

[0032] Firstly, the filling position was optimized, with the wheel bead seat (position 9) chosen as the filling inlet. Furthermore, existing wheel designs use multiple gates on the outer side, where molten metal enters the mold cavity vertically or obliquely. Due to the abrupt change in area, this results in abrupt changes in flow pattern, easily causing turbulence, air entrapment, and oxidation inclusions. To address these issues, this invention employs a casting structure assembly including multiple casting channels, changing the molten metal flow from vertical to horizontal into the bead seat, allowing it to enter the mold cavity in a horizontal laminar flow along the circumferential direction of the transverse runner. This achieves the smoothest possible synchronous liquid entry along the circumference of the bead seat, increasing the entry area while reducing the molten metal velocity, resulting in smoother filling, reduced turbulence, air entrapment, and secondary oxidation inclusions during the filling process.

[0033] Furthermore, since the wheel to be formed in this invention has a five-spoke structure, five-spoke wheels have been widely used in the automotive industry in recent years due to their longer and simpler spokes, better overall appearance, more even force distribution during driving, and lower wind resistance. However, five-spoke wheels have an asymmetrical structure, with an angle of 72° between each spoke. For wheel casting, symmetrical casting methods (2, 3, or 4 gating channels, etc.) are usually used because these methods are more convenient for equipment and mold design and have better versatility, making them easier to apply to the production of other types of wheels. Therefore, when using symmetrical multi-channel filling for asymmetrical five-spoke wheels, inconsistent filling times for each spoke can easily lead to problems such as air entrapment and uncontrollable solidification sequence, resulting in casting defects. Therefore, when casting five-spoke wheels, it is necessary to design the wheel structure and gating system structure to avoid the above problems.

[0034] Based on the above considerations, this invention has made targeted designs for the wheel structure and cast structural components, such as... Figure 4 As shown, the casting structure 13 includes four casting channels of three different structures: a first casting channel 16, a second casting channel 17, and two third casting channels 18. The included angle between the four casting channels is 90°.

[0035] Furthermore, due to the adoption of a horizontal pouring method using a pouring channel, which differs from existing technologies, the two pouring channels handle different numbers of spokes, resulting in significant differences in the flow area and arc length. Consequently, the flow behavior will exhibit marked differences. The molten metal flow field is highly sensitive to the channel cross-sectional characteristics and process parameters: cross-sections with abrupt area changes and high irregularity can lead to turbulent flow and air entrapment, and mismatches between filling speed and pressure can cause uneven filling.

[0036] Therefore, it is necessary to design the relevant dimensional parameters of the pouring channels for the three structures to ensure smooth and rapid filling, avoid air entrapment, turbulence, and casting defects, and minimize the amount of molten metal used. Specifically: First, define the design parameters for the gating system, including: 1) Effective flow area : refers to the cross-sectional area of ​​the upper surface of the pouring channel; 2) Profile feature value W: is the ratio of the perimeter of the profile of the upper surface of the pouring channel to the perimeter of a circle with the same area as the pouring channel.

[0037] The following constraints are adopted:

[0038] In the formula, The effective flow area of ​​the second pouring channel. This refers to the effective flow area of ​​other pouring channels.

[0039]

[0040] In the formula, The profile feature value of the second pouring channel. These are the contour feature values ​​for other pouring channels.

[0041] and:

[0042] In determining the above indicators, the five-spoke wheel casting system of this invention adopts a distribution method of 1 single-spoke channel + 2 double-spoke channels. The effective flow area directly determines the flow capacity and is the core of flow matching; the profile feature value determines the regularity of the cross-section and is the core of controlling flow resistance and eddies. The two indicators work together to limit the effective flow area ratio, reduce the time difference of the molten metal reaching the spokes, and avoid the problem of some spokes being filled too quickly and others too slowly. Through the constraint of the profile feature value, the liquid flow separation and eddies caused by rapidly expanding cross-sections and highly irregular cross-sections are avoided, allowing the molten metal to maintain a laminar / weakly turbulent state in the channel, greatly reducing the probability of the cavity gas being trapped, and achieving a balance between quality, efficiency and cost.

[0043] Based on the above principles and after practical verification, the angles between each pouring channel and each spoke pouring inlet were designed, such as... Figure 4 As shown, the first pouring channel 16 is directly opposite a spoke, and there are two third pouring channels 18 on its two sides. The two third pouring channels 18 are also directly opposite a spoke. The second pouring channel 17 is symmetrically arranged relative to the first pouring channel 16, that is, the angle between the two is 180°. The second pouring channel 17 is located in the middle of the two spokes.

[0044] Each pouring channel includes an initial pouring area and an extended pouring area connecting the initial pouring area and the runner. The top view of the initial pouring area is semi-circular, and the shape of each type of extended pouring area is different. From the top view, taking the lower rim surface of the wheel as the reference surface and the line connecting the center of each pouring channel to the wheel core as the reference, the angle between the line connecting the center of the first pouring channel 16 to the wheel core and the side of the first pouring channel 16 in the clockwise direction is α1=20°, and the angle between the line connecting the center of the first pouring channel 16 to the side of the first pouring channel 16 in the counterclockwise direction is α2=8°. The angle between the line connecting the center of the second pouring channel 17 and the wheel core and the side of the clockwise second pouring channel 17 is γ2=40°, and the angle between the line connecting the center of the second pouring channel 17 and the side of the counterclockwise second pouring channel 17 is γ1=40°. The angle between the line connecting the center of the third pouring channel 18 and the wheel core and the side of the third pouring channel 18 in the clockwise direction is β2=12°, and the angle between the line connecting the center of the third pouring channel 18 and the side of the third pouring channel 18 in the counterclockwise direction is β1=40°.

[0045] Effective flow area of ​​the first pouring channel: 630-730 cm² 2 The effective flow area of ​​the second pouring channel is 810–910 cm². 2 The effective flow area of ​​the third pouring channel is 630–730 cm². 2 .

[0046] Verification has shown that the above design allows for a larger surface area for molten metal to flow into each spoke at the set filling speed, with closer filling distances, a lower overall filling speed (not exceeding 0.5 m / s), no turbulence or air entrapment, and smoother bottom-up filling. Furthermore, the short filling process, with areas of prolonged air contact primarily located at the inner rim and center riser, effectively alleviates or eliminates heat spots at the spoke-rim junction. Molten metal utilization is increased by 15%–25%. The temperature at the molten metal tip during filling is not lower than 616℃, eliminating the risk of incomplete pouring.

[0047] Furthermore, a cooling system is used during the casting process. The solidification sequence of the wheel is adjusted from the traditional low-pressure casting single-gate process to four directions: from the upper rim to the gate, from the middle of the spokes to the gate, from the middle of the spokes to the center riser, and from the lower rim without a gate to the position with a gate. To achieve this, an upper mold cooling mechanism, a lower mold cooling mechanism, and a side mold cooling mechanism are designed on the mold. The cooling channels and opening sequence of the cooling mechanisms are also designed to achieve sequential solidification of the wheel in each direction.

[0048] Specifically, the upper mold cooling mechanism includes at least an annular water cooling channel in the middle of the wheel spoke, with the distance between the annular water cooling channel in the middle of the wheel spoke and the wheel core being 130mm to 150mm. The lower mold cooling mechanism includes at least an annular water cooling channel in the middle of the wheel spoke, with the distance between the annular water cooling channel in the middle of the wheel spoke and the wheel core being 160mm to 180mm.

[0049] The annular water-cooling channel in the middle of the two spokes is used to achieve sequential solidification from the middle of the spokes to the gate and from the middle of the spokes to the center riser.

[0050] Based on the above cooling system design, the activation sequence of the cooling components in each direction is as follows: First, simultaneously activate the annular water cooling channel of the upper mold at the center of the spokes and the annular water cooling channel of the lower mold at the center of the spokes. Then, activate other water-cooling, air-cooling, or spot-cooling components to achieve sequential solidification from the center of the spokes to the gate direction and from the center of the spokes to the center riser direction.

[0051] The aforementioned cooling method addresses the issue that existing cooling methods aim for unidirectional sequential solidification from the outermost inner rim to the gate to ensure feeding. However, due to the thin wall thickness of the wheel rim and the long filling distance, the temperature at the leading edge of the molten metal drops extremely rapidly when filling the thin-walled rim. To prevent premature solidification at the thin-walled area, leading to cold shuts or insufficient filling, the filling temperature of the molten metal must be significantly increased. However, the long-distance flow of high-temperature molten metal results in coarse grains in the casting, significantly reducing its mechanical properties. Furthermore, the traditional single-gate process has only one main feeding channel (from the wheel core to the rim), which easily leads to isolated hot spots in areas far from the gate. Once the thin-walled part in the middle (such as the rim) solidifies first, closing the channel, the distant hot spots lose their feeding source, easily causing concentrated shrinkage cavities and porosity defects. By combining multiple cooling channels and adjusting the opening sequence of each channel, the traditional single sequential solidification path is redesigned into four directions, two of which are sequential solidification from the center of the spokes to the gate and from the center of the spokes to the central riser. This design method shortens the effective solidification and feeding distance of all areas by more than half. It ensures that distant parts are covered by the short feeding channel, fundamentally eliminating the risk of premature solidification of thin-walled sections, avoiding the generation of concentrated shrinkage cavities and porosity defects, and significantly improving the casting quality and mechanical properties of wheels.

[0052] The method for wheel forming using the above-mentioned device includes stages of liquid lifting, mold filling, crystallization pressurization and holding, and pressure release and venting. Here, the molten metal used is molten aluminum, and the specific steps are as follows: (1) Liquid rising stage: The aluminum liquid in the holding furnace is pressurized by a high-pressure gas source, so that the aluminum liquid rises along the liquid rising pipe to a position about 100mm below the gate. The pressurization rate in this stage is 13mbar / s to 18mbar / s, and the pressure is increased to 110mbar to 130mbar.

[0053] (2) Filling stage: Continue to increase the pressure. The pressure increase rate in this stage is 4mbar / s to 6mbar / s, increasing the pressure to 225mbar to 235mbar, so that the aluminum liquid fills the cavity.

[0054] (3) Shell formation stage: After the filling stage is completed, the pressure is increased to 230mbar to 250mbar at a pressurization rate of 2mbar / s to 4mbar / s.

[0055] (4) Extrusion, pressurization and holding stage: ① After the shelling stage is completed, the pressure is rapidly increased to 800 mbar at a pressurization rate of 30 mbar to 60 mbar / s and held for 100 to 120 seconds. At this time, the wheel solidification is completed. ② When the filling stage is completed and the timer reaches 50 to 70 seconds, the extrusion cylinder is started, and the extrusion pin connected to it is driven to move downward from the initial position by 40 to 50 mm at a speed of 2 mm / s to 5 mm / s (the initial position and stroke of the extrusion are determined by the center structure of the wheel) and held in this position for 50 to 70 seconds. After that, under the drive of the extrusion cylinder, the extrusion pin is withdrawn to the initial position, that is, separated from the extruded wheel to avoid affecting the normal demolding of the product.

[0056] (5) Depressurization and venting stage: After the pressure holding stage is completed, that is, the aluminum alloy wheel is solidified, the gas pressure in the heat holding furnace is released, and the unsolidified aluminum liquid in the riser pipe and the gate flows back into the heat holding furnace. Then, the wheel is kept in the mold for 70s to 100s before the mold is opened and the part is removed.

[0057] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A tire wheel casting apparatus based on multi-gating with tire bead seat, comprising: A heat-holding furnace, a riser pipe, a mold, and a pressure system; the heat-holding furnace stores and keeps the molten metal at a constant temperature; the mold has a cavity for the molten metal to solidify and form; the riser pipe is located below the heat-holding furnace and connected to a pouring cup above the riser pipe; the pressure system controls the molten metal to flow through the riser pipe and into the cavity of the mold via the pouring cup. The system is characterized in that... The molten metal is poured into the runner through the sprue cup and the gating structure, and then into the mold cavity. The runner is located at the tire bead seat of the wheel, encircles the wheel, and connects to the mold cavity. The molten metal rises vertically in the riser and sprue cup, then becomes horizontal in the gating structure and is poured horizontally into the runner and the mold cavity. The gating structure includes a first gating channel, a second gating channel, and two third gating channels. The included angle between any two adjacent gating channels is 90°, and each includes a gate connected to the runner. The effective flow area and profile feature value of the first, second, and third gating channels are determined based on the molten metal filling flow conditions. The effective flow area is the cross-sectional area of ​​the upper surface of the gating channel. The profile feature value is the ratio of the perimeter of the cross-sectional profile of the upper surface of the gating channel to the perimeter of a circle with the same area as the gating channel. The wheel casting equipment also includes a cooling system; the cooling system makes the sequential solidification process of the wheel forming process include four directions: from the uppermost inner rim to the gate, from the middle of the spokes to the gate, from the middle of the spokes to the center riser, and from the lowermost outer rim to the gate. The first pouring channel is directly opposite one spoke. Two third pouring channels are on either side of the first pouring channel, each directly opposite one spoke. The second pouring channel is symmetrically arranged relative to the first pouring channel, that is, the included angle between the second pouring channel and the first pouring channel is 180°, and the second pouring channel is located in the middle of the two spokes.

2. The tire bead seat based multi-gating type wheel casting forming apparatus according to claim 1, characterized by, The first pouring channel is responsible for filling and pouring one spoke, the two third pouring channels are each responsible for filling and pouring one spoke, and the second pouring channel is responsible for filling and pouring two spokes.

3. The tire bead seat based multi-gating type wheel casting forming apparatus according to claim 2, characterized by, Each pouring channel includes an initial pouring zone and an extended pouring zone located between the initial pouring zone and the runner.

4. The wheel casting molding equipment based on the multi-gate filling mold of the outer tire bead seat according to claim 3, characterized in that, The top view of the initial pouring zone is semi-circular.

5. A method for wheel casting using the wheel casting equipment based on the multi-gate filling mold of the tire bead seat as described in any one of claims 1-4, characterized in that, It includes the liquid rising stage, the filling stage, the shell forming stage, the pressure increasing, extrusion and pressure holding stage, and the pressure release and venting stage.

6. The wheel casting method according to claim 5, characterized in that, During the filling stage, the filling speed of the molten metal should not exceed 0.5 m / s.

7. The wheel casting method according to claim 6, characterized in that, During the filling stage, the temperature of the molten metal front end should not be lower than 616℃.

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