Magnesium alloy wheel manufacturing assembly die

Abstract

The application discloses a magnesium alloy wheel manufacturing combined die, which comprises a casting die and a forging die. The casting die comprises a first upper die plate, a first upper punch, a first lower die plate, a first lower punch and a first side punch. The first lower punch is provided with a first boss and a second boss on the top. The first side punch is installed on the first lower punch to form a die cavity. The forging die comprises a second upper die plate, a second upper punch, a second lower die plate, a second lower punch and a second side punch. The bottom of the second upper punch is provided with a third boss and a fourth boss. The diameter of the third boss is smaller than that of the first boss, and the diameter of the fourth boss is smaller than that of the second boss. The top of the second lower punch is provided with a first groove and a second groove. The second side punch is installed on the second lower die plate to form a die cavity. The magnesium alloy wheel is manufactured by using the two sets of combined dies in sequence, so that the problem that the spokes of the magnesium alloy wheel cannot be directly formed is solved, and the mechanical properties of the spokes are improved.

Description

Technical Field

[0001] This invention belongs to the field of liquid metal casting and plastic forming technology of metal materials, and in particular refers to a combined mold for manufacturing magnesium alloy wheels. Background Technology

[0002] As one of the main load-bearing components of a vehicle, the wheel, based on its actual working conditions, has relatively complex stress conditions. The hub and spokes, connected to the drive shaft, bear various alternating loads such as tension, compression, bending, and torsion, thus requiring higher performance. The rim and flange, on the other hand, mainly bear torsional and compressive stresses, with relatively lower performance requirements. Currently, magnesium alloy wheels are manufactured using two processes: casting and forging. For example, Chinese invention patent ZL03109034.6, "A Manufacturing Method for a Magnesium Alloy Wheel Hub" (authorization announcement number CN100515804C), discloses a casting method for preparing magnesium alloy wheel hubs. A similar patent can be found in ZL200610086359.0. While casting is simpler, lower in cost, and has higher material utilization, the mechanical properties of the material sampled from the wheel itself are relatively low, with a tensile strength of only about 200 MPa, which cannot meet the mechanical requirements of the hub and spokes. Furthermore, the internal structure of the wheel... The structure is also prone to casting defects such as looseness, inclusions, and porosity, resulting in poor density and low product qualification rate. For example, Chinese patent CN105665610B discloses a forging method for magnesium alloy automobile wheel hubs. This patent adopts a forging forming method. Although the tensile strength of the material reaches about 300 MPa, the internal structure is pure, the density is high, and the product qualification rate is high, the process is complicated, especially the forming of the wheel spokes. In order to improve the mechanical properties of the wheel spokes, multiple heating, multiple mold changes, and multiple pre-forming aggregates are required during forging. The wheel spokes cannot be formed directly, resulting in low production efficiency and high cost. Summary of the Invention

[0003] The purpose of this invention is to provide a combined mold for manufacturing magnesium alloy wheels, including two sets of molds for casting and forging. By adopting a method of casting first and then forging, the problem of the wheel spokes of magnesium alloy wheels cannot be directly formed is solved. At the same time, the mechanical properties of the wheel spokes are improved, the wheel forming cycle is shortened, the material utilization rate is increased, the cost is reduced, and the product qualification rate is high.

[0004] To achieve the above objectives, the solution of the present invention is: a combined mold for manufacturing magnesium alloy wheels, comprising a casting mold and a forging mold, wherein the magnesium alloy wheels are manufactured by sequentially using the casting mold and the forging mold;

[0005] The casting mold includes a first upper template, a first upper punch, a first lower template, a first lower punch, and a first side punch. The first upper punch is fixed to the bottom of the first upper template, and the first lower punch is fixed to the top of the first lower template. The top of the first lower punch has a first boss and a second boss. The first side punch is installed on the first lower punch, and there are multiple first side punches. The multiple first side punches form a mold cavity. After the raw material is poured into the mold cavity, the first upper template moves downward to make the first upper punch extrude the raw material to form a casting billet. The first upper punch is pressed down to abut against the first boss and the second boss to form the hub center hole and spoke hole on the casting billet, so that the casting billet initially forms a hub and spokes. During extrusion, a gap is left between the first upper punch and the first side punch to form a rim and flange.

[0006] The forging die includes a second upper template, a second upper punch, a second lower template, a second lower punch, and a second side punch. The second upper punch is fixed to the bottom of the second upper template, and a third boss and a fourth boss protrude from the bottom of the second upper punch. The diameter of the third boss is smaller than the diameter of the first boss, and the diameter of the fourth boss is smaller than the diameter of the second boss. The second lower punch is fixed to the top of the second lower template, and the top of the second lower punch has a first groove and a second groove that respectively mate with the third boss and the fourth boss. The second side punch is installed on the second lower template and its lower part abuts against the second lower punch laterally. There are multiple second side punches, and the multiple second side punches surround to form a die cavity. After the heated billet is placed into the die cavity, the second upper template moves downward to make the second upper punch squeeze the bottom of the billet until the third boss and the fourth boss are embedded in the first groove and the second groove respectively. The billet flows towards the third boss and the fourth boss and fills the die cavity, completing the forging of the wheel.

[0007] Furthermore, the bottom surface of the first upper punch and the top surface of the first lower punch are horizontal flat surfaces, the top surfaces of the wheel hub and spokes of the cast billet are on the same horizontal plane, and the bottom surfaces of the wheel hub, spokes and rim are on the same horizontal plane.

[0008] Furthermore, the casting mold also includes a mold-locking mechanism, which laterally pushes against the first side punch to lock the mold or moves away from the first side punch to release the mold.

[0009] Furthermore, the mold-locking mechanism adopts a side mold cylinder, which is equipped with a telescopic rod. The telescopic rod extends to push against the first side punch to lock the mold, and retracts to release the mold lock.

[0010] Furthermore, the bottom surface of the second upper punch and the top surface of the second lower punch are undulating arc surfaces, and the inner end of the forged wheel spokes bends upward to make the wheel hub convex overall, while the bottom surface of the wheel rim is concave upward.

[0011] Furthermore, the forging die also includes a sleeve, a push rod, and an ejector block. The sleeve is fitted around the outer periphery of the second side punch to form a locking die. The push rod passes through the second lower punch and the second lower template and its bottom end is exposed. The ejector block is located on top of the push rod. The push rod moves upward to push the ejector block out the forged wheel.

[0012] Furthermore, the ejector block is located in the middle of the second lower punch, and a first groove is formed in the ejector block to cooperate with the third boss.

[0013] After adopting the above scheme, the gain effect of the present invention is as follows:

[0014] 1. This invention includes two sets of molds: a casting mold and a forging mold. First, the raw material is poured into the casting mold to form a cast billet, which already has the basic shape of a wheel. Then, the cast billet is heated and placed in the forging mold for forging, giving the hub and spokes the required mechanical properties. The diameter of the third boss is smaller than the diameter of the first boss, and the diameter of the fourth boss is smaller than the diameter of the second boss. The inner diameter of the hub center hole and spoke hole in the cast billet is larger than the inner diameter of the hub center hole and spoke hole in the forged wheel, allowing the hub and spokes room to deform during subsequent forging. This allows excess material from the cast billet to flow towards the hub center hole and spoke hole, thus enabling successful forging, reducing the size of the hub center hole and spoke hole, improving the mechanical properties of the hub and spokes, and preventing material waste, thereby saving production costs.

[0015] 2. The casting mold and forging mold of the present invention can directly process and form the spoke shape of the wheel, while improving its mechanical properties. It avoids the cumbersome process of multiple heating, multiple mold changes and multiple pre-forming of materials after forging. It also reduces the processing and forming process of the spoke shape after forging. The operation is more convenient, the wheel forming cycle is shortened, the production efficiency is improved and the production cost is saved.

[0016] 3. By combining the casting mold and forging mold of the present invention, the direct forming of wheel spokes in the magnesium alloy wheel forming process is realized through the "casting and forging" process. This not only allows for the forming of spokes of any shape and number, but also improves their mechanical properties. It avoids the multiple material accumulation processes and defects such as folding, instability, and incomplete filling that occur in the forging of magnesium alloy wheels, ensuring the integrity of the metal flow lines, realizing overall plastic forming, and improving mechanical properties. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of the casting mold of the present invention;

[0018] Figure 2 This is a cross-sectional view of the billet of the present invention;

[0019] Figure 3 This is a schematic diagram of the structure of the casting billet of the present invention;

[0020] Figure 4 This is a cross-sectional view of the forging die of the present invention;

[0021] Figure 5 This is a cross-sectional view of the wheel of the present invention;

[0022] Figure 6 This is a schematic diagram of the structure of the wheel of the present invention.

[0023] Label Explanation:

[0024] 1. Hub; 2. Spoke; 3. Rim; 4. Edge; 5. Spoke hole; 6. Hub center hole; 7. First upper mold plate; 8. First upper punch; 9. First lower mold plate; 10. First lower punch; 11. First side punch; 12. First boss; 13. Second boss; 14. Side mold cylinder; 15. Second upper mold plate; 16. Second upper punch; 17. Second lower mold plate; 18. Second lower punch; 19. Second side punch; 20. Third boss; 21. Fourth boss; 22. First groove; 23. Second groove; 24. Sleeve; 25. Ejector rod; 26. Ejector block. Detailed Implementation

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

[0026] like Figure 5 and Figure 6 As shown, the wheel that can be manufactured by the manufacturing mold of the present invention includes a hub 1, spokes 2, rim 3 and flange 4. The hub 1 has a hub center hole 6 at its center, and the spokes 2 have multiple spokes, with spoke holes 5 formed between adjacent spokes 2.

[0027] like Figure 1-6As shown, this invention provides a combined mold for manufacturing magnesium alloy wheels, including a casting mold and a forging mold. The casting mold includes a first upper mold plate 7, a first upper punch 8, a first lower mold plate 9, a first lower punch 10, and a first side punch 11. The first upper punch 8 is fixed to the bottom of the first upper mold plate 7, and the first lower punch 10 is fixed to the top of the first lower mold plate 9. A first boss 12 and a second boss 13 are protruding from the top of the first lower punch 10 or the bottom of the first upper punch 8. In this invention, the first boss 12 and the second boss 13 are protruding from the top of the first lower punch 10. The first side punch 11 is mounted on the first lower punch 10, and there are multiple first side punches 11, which together form a mold cavity. The raw material for casting is molten magnesium alloy, which is poured into the mold cavity. Inside the mold cavity, after pouring, the first upper mold plate 7 is moved downwards to extrude the magnesium alloy melt by the first upper punch 8 until the first upper punch 8 abuts against the first boss 12 and the second boss 13, maintaining the extrusion state to complete the casting. The first boss 12 and the second boss 13 can extrude the hub center hole 6 and the spoke hole 5, so that the cast billet has a pre-formed hub 1 and spoke 2. During extrusion, a gap is left between the first upper punch 8 and the first side punch 11 to form the rim 3 and the flange 4. Therefore, the cast billet has a hub 1, spoke 2, rim 3 and flange 4, and already has the basic shape of a wheel. The casting mold can be adjusted according to the required shape of the wheel to form the basic shape of the wheel. For example, the number and shape of the second boss 13 can be adjusted to adjust the number and shape of the spoke 2. It should be noted that the diameters of the first boss 12 and the second boss 13 are slightly larger, and the inner diameters of the formed hub center hole 6 and spoke hole 5 are larger than the inner diameters of the hub center hole 6 and spoke hole 5 of the final manufactured wheel. This leaves room for the subsequent deformation of the forging billet, enabling the forging to complete the shrinkage and precise forming of the wheel spoke 2, thereby improving the mechanical properties of the hub 1 and spoke 2.

[0028] Key references Figure 1 The first casting mold also includes a mold-locking mechanism. After the first side punch 11 is assembled and the mold is closed, the mold can be locked by the mold-locking mechanism. The mold-locking mechanism is preferably a side mold cylinder 14. The telescopic rods of multiple side mold cylinders 14 extend and push the first side punch 11 laterally to fix the first side punch 11, thereby completing the mold locking. The mold-locking force of the side mold cylinder 14, i.e., the pushing force, is greater than the expansion force of the magnesium alloy melt, so that when the first upper punch 8 presses the magnesium alloy melt downward, the magnesium alloy melt will not leak out. Moreover, the first side punch 11 is subjected to pressure on both the inner and outer sides, and the force is uniform, which can better form the casting billet. After casting is completed, the telescopic rods of the side mold cylinder 14 retract and move away from the first side punch 11, releasing the mold lock, making the first side punch 11 easy to disassemble. The casting billet can then be removed to complete the demolding, which is convenient for demolding. It should be noted that the mold must be locked before pouring. If the mold is locked after pouring, it will accelerate the cooling rate of the magnesium alloy melt, which is not conducive to the magnesium alloy melt filling the entire cavity.

[0029] like Figure 2 and Figure 3 As shown, the casting mold extrudes the magnesium alloy melt into the basic shape of a wheel. The bottom surface of the first upper punch 8 and the top surface of the first lower punch 10 are horizontal flat surfaces, so that the top surfaces of the wheel hub 1 and the spokes 2 of the casting blank are on the same horizontal plane, and the bottom surfaces of the wheel hub 1, the spokes 2 and the rim 3 are on the same horizontal plane, thereby ensuring uniform extrusion and avoiding casting defects such as looseness, inclusions and porosity.

[0030] like Figure 4-6 As shown, the forging die includes a second upper template 15, a second upper punch 16, a second lower template 17, a second lower punch 18, and a second side punch 19. The second upper punch 16 is fixed to the bottom of the second upper template 15. A third boss 20 and a fourth boss 21 are protruding from the bottom of the second upper punch 16. The diameter of the third boss 20 is smaller than the diameter of the first boss 12, and the diameter of the fourth boss 21 is smaller than the diameter of the second boss 13. The second lower punch 18 is fixed to the top of the second lower template 17. The top of the second lower punch 18 is provided with a first groove 22 and a second groove 23 that respectively mate with the third boss 20 and the fourth boss 21. The second side punch 19... The punch 19 is installed on the second lower template 17 and its bottom abuts against the second lower punch 18 laterally. There are multiple second side punches 19, which together form a mold cavity. After the heated billet is placed into the mold cavity, the second upper template 15 is pressed down so that the second upper punch 16 squeezes the bottom of the billet, causing the billet to deform and flow in the cavity. The second upper template 15 is pressed down further so that the third boss 20 and the fourth boss 21 are respectively embedded in the first groove 22 and the second groove 23. The billet flows towards the third boss 20 and the fourth boss 21, thereby reducing the inner diameter of the hub center hole 6 and the spoke hole 5. Finally, the billet fills the cavity, completing the forging of the wheel. After forging, the wheel spoke 2 shape can be directly formed, which improves its mechanical properties. This avoids the cumbersome process of multiple heating, mold changes and pre-forming of materials after forging. It also reduces the processing and forming process of the wheel spoke 2 shape after forging, making the operation more convenient, improving production efficiency and saving production costs.

[0031] The forging die also includes a sleeve 24, a push rod 25, and an ejector block 26. The sleeve 24 is fitted around the outer periphery of the second side punch 19 and forms a locking mold with an interference fit with the second side punch 19. The push rod 25 passes through the second lower punch 18 and the second lower template 17 and its bottom end is exposed. The ejector block 26 is located on the top of the push rod 25. The ejector block 26 is preferably located at the center of the second lower punch 18, so the ejector block 26 can be embedded in the center of the second lower punch 18. A first groove 22 is opened in the ejector block 26 to cooperate with the third boss 20. After forging is completed, the push rod 25 can move upward to push the ejector block 26 to eject the forged wheel, making demolding convenient and quick.

[0032] like Figure 5 and Figure 6 As shown, the forging die mainly forges the bottom of the wheel, that is, it mainly extrudes the hub 1, spokes 2, and rim 3. It not only reduces the center hole 6 of the hub and the spoke hole 5, but also forges the hub 1, spokes 2, and rim 3 into the required shape. The bottom surface of the second upper punch 16 and the top surface of the second lower punch 18 are undulating arc surfaces. The bottom of the second upper punch 16 has a downward convex point p and an upward concave point q from the outside to the inside. When the second upper die 15 pushes the second upper punch 16 downward, point P contacts the billet first, and the contact area undergoes plastic deformation first. Under the combined action of the wedge pressing structure and surface friction at point q, The flow direction of the cast billet is forced to adjust, flowing within the closed cavity formed between the second upper punch 16 and the second lower punch 18. As the second upper punch 16 continues to press down, the third boss 20 passes through the hub center hole 6 of the cast billet and is embedded in the first groove 22, and the fourth boss 21 passes through the spoke hole 5 of the cast billet and is embedded in the second groove 23. The cast billet flows around the third boss 20 and the fourth boss 21. Once the metal fills the cavity, the forging is completed. The inner end of the forged wheel spoke 2 bends upward, making the hub 1 convex overall, and the bottom surface of the rim 3 is concave upward, thereby improving the mechanical properties of the hub 1 and the spoke 2 and meeting the complex stress conditions of the hub 1 and the spoke 2.

[0033] The process of casting and forging wheels using this invention is as follows: First, AZ80 magnesium alloy is melted according to the component ratio, and purified through processes such as melting, refining, settling, and slag removal to obtain magnesium alloy melt; then, the casting mold is assembled, the casting mold is preheated, and the mold is locked using the side mold cylinder 14; then, a fixed amount of magnesium alloy melt is poured into the casting mold cavity. The volume of the required magnesium alloy melt (including the estimated volume such as the required machining allowance) is determined according to the volume of the wheel to be prepared. After the magnesium alloy melt fills the cavity, pouring is stopped, and the first upper mold plate 7 is driven down by a press to press down the first upper punch 8 to squeeze the magnesium alloy melt. The squeezing state is maintained for 60 seconds to complete the casting. Figure 2As shown, the inner diameters of the hub center hole 6 and spoke hole 5 of the cast billet are d0 and d1 respectively, and the inner diameter of the rim 3 is D and the height is H. Then, the mold is released, the billet is demolded and removed, and after the billet cools, it is uniformly annealed and heated. Next, the forging mold is assembled, the forging mold is preheated, and the hot forging mold is installed on a 1250T hydraulic press, while the mold heat preservation device is turned on. After the billet is heated, it is placed into the cavity of the forging mold, and the extrusion temperature is controlled at 350℃, the extrusion speed is 1mm / s, and the deformation degree is 35%. The hydraulic press drives the second upper mold plate 15 to move downward, so that the second upper punch 16 presses down on the billet. After the billet fills the closed cavity formed between the second upper punch 16 and the second lower punch 18, the forging is completed. Finally, the upper push rod 25 pushes out the forged wheel, as shown. Figure 5 The inner diameters of the spoke hole 5 and the center hole 6 of the forged wheel are d3 and d2, respectively. The inner diameter of the rim 3 is D and the height is H. The hole diameter relationship between the cast billet and the forged wheel is: d1>d3, d0>d2. The mechanical performance requirements of the rim 3 and the flange 4 are relatively low. The side of the rim 3 and the flange 4 are not the main forging parts, so the inner diameter and height of the rim 3 are still D and H, with almost no change. Finally, the forged wheel is heat-treated at 177℃ for 24 hours to give the wheel higher comprehensive mechanical properties. The mechanical properties sampled from the spoke 2 of the wheel are 290-310 MPa, yield strength 200-240 MPa, and elongation 7-10%, which meet the mechanical requirements of the spoke 2.

[0034] In addition, during pouring, flux and oxides on the surface of the magnesium alloy melt should be removed, and CO2 gas should be used to protect the surface of the magnesium alloy melt to avoid casting defects such as inclusions and porosity. Furthermore, the pouring temperature should be slightly higher than that used in extrusion casting to facilitate the flow of the molten magnesium alloy and ensure it fills the mold cavity. After the casting mold is assembled, a release agent needs to be sprayed onto the mold cavity surface to facilitate subsequent demolding of the cast billet. Similarly, after the forging mold is assembled, graphite needs to be sprayed onto the cavity surface as a lubricant to facilitate extrusion forging and subsequent wheel demolding.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the design of this case. All equivalent changes made based on the key design features of this case shall fall within the protection scope of this case.

Claims

1. A combined mold for manufacturing magnesium alloy wheels, characterized in that: Including casting molds and forging molds, magnesium alloy wheels were manufactured using both casting molds and forging molds. The casting mold includes a first upper template, a first upper punch, a first lower template, a first lower punch, and a first side punch. The first upper punch is fixed to the bottom of the first upper template, and the first lower punch is fixed to the top of the first lower template. The top of the first lower punch has a first boss and a second boss. The first side punch is installed on the first lower punch, and there are multiple first side punches. The multiple first side punches form a mold cavity. After the raw material is poured into the mold cavity, the first upper template moves downward to make the first upper punch extrude the raw material to form a casting billet. The first upper punch is pressed down to abut against the first boss and the second boss to form the hub center hole and spoke hole on the casting billet, so that the casting billet initially forms a hub and spokes. During extrusion, a gap is left between the first upper punch and the first side punch to form a rim and flange. The forging die includes a second upper die plate, a second upper punch, a second lower die plate, a second lower punch, and a second side punch. The second upper punch is fixed to the bottom of the second upper die plate. A third boss and a fourth boss protrude from the bottom of the second upper punch. The diameter of the third boss is smaller than the diameter of the first boss, and the diameter of the fourth boss is smaller than the diameter of the second boss. The second lower punch is fixed to the top of the second lower die plate. The top of the second lower punch has a first groove and a second groove that respectively mate with the third boss and the fourth boss. The second side punch is installed on the second lower die plate. The upper and lower parts of the plate abut against the second lower punch laterally. The second side punch has multiple parts, and the multiple second side punches surround to form a mold cavity. After the heated billet is placed into the mold cavity, the lower second upper platen causes the second upper punch to squeeze the bottom of the billet until the third and fourth bosses are embedded in the first and second grooves respectively. The billet flows towards the third and fourth bosses and fills the mold cavity, completing the forging of the wheel. The inner diameter of the hub center hole and the spoke hole on the billet is larger than the inner diameter of the hub center hole and the spoke hole of the final prepared wheel.

2. The magnesium alloy wheel manufacturing assembly mold as described in claim 1, characterized in that: The bottom surface of the first upper punch and the top surface of the first lower punch are horizontal flat surfaces. The top surfaces of the wheel hub and spokes of the cast billet are on the same horizontal plane, and the bottom surfaces of the wheel hub, spokes and rim are on the same horizontal plane.

3. The magnesium alloy wheel manufacturing assembly mold as described in claim 1, characterized in that: The casting mold also includes a mold-locking mechanism, which laterally pushes against the first side punch to lock the mold or moves away from the first side punch to release the mold.

4. The magnesium alloy wheel manufacturing assembly mold as described in claim 3, characterized in that: The mold-locking mechanism uses a side mold cylinder, which is equipped with a telescopic rod. The telescopic rod extends to push against the first side punch to lock the mold, and retracts to release the mold lock.

5. The magnesium alloy wheel manufacturing assembly mold as described in claim 1, characterized in that: The bottom surface of the second upper punch and the top surface of the second lower punch are undulating arc surfaces. The inner end of the forged wheel spokes bends upward to make the wheel hub convex overall, and the bottom surface of the wheel rim is concave upward.

6. The combined mold for manufacturing magnesium alloy wheels as described in claim 1, characterized in that: The forging die also includes a sleeve, a push rod, and an ejector block. The sleeve is fitted around the outer periphery of the second side punch to form a locking die. The push rod passes through the second lower punch and the second lower template and its bottom end is exposed. The ejector block is located on top of the push rod. The push rod moves upward to push the ejector block out the forged wheel.

7. The magnesium alloy wheel manufacturing assembly mold as described in claim 6, characterized in that: The ejector block is located in the middle of the second lower punch, and a first groove is formed in the ejector block to cooperate with the third boss.

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