A wheel hub casting mold and a wheel hub casting cooling process

Abstract

The application relates to a wheel hub casting mold, which comprises an upper mold, a side mold, a lower mold and a cooling device, the upper mold, the side mold and the lower mold form a casting cavity after being combined, a sprue is arranged on the side mold, a center column protruding upwards is arranged on the lower mold, and the cooling device is used for cooling the casting cavity to form a wheel hub blank in the casting cavity; the cooling device comprises a center cooling structure, an intermediate cooling structure and an outer cooling structure; the center cooling structure comprises a center column liquid cooling cavity arranged in the center column and an annular liquid cooling cavity arranged in the upper mold and surrounding the center column; the center cooling structure, the intermediate cooling structure and the outer cooling structure are started in sequence during use so that the wheel hub blank is solidified from the center to the rim in sequence. The application realizes reliable feeding by reforming the structure of the casting mold and controlling the solidification sequence of the whole casting, and feeding risers are reduced or omitted.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wheel hub casting, in particular to the technical field of low pressure casting, and specifically to a wheel hub casting mold and a wheel hub casting cooling process. BACKGROUND

[0002] Most of the wheel hubs on the market are cast by low pressure casting process. Low pressure casting process is a processing process of cooling and forming by pressing liquid alloy into a casting mold under low pressure. Low pressure casting not only meets the needs of complex and delicate modeling, but also has the advantages of good formability, clear contour and uniform density.

[0003] The low pressure casting of the wheel hub adopts a center position bottom pouring mode, and the metal liquid flows to the rim through the spokes. In the casting process, the rim has a long and difficult shrinkage path, which is prone to shrinkage porosity problems, affecting the performance of the casting. Moreover, the center bottom pouring mode takes a long time to complete pouring, resulting in a relatively long casting time and low production efficiency.

[0004] To solve the above problems, a double-sided pouring mode can be used. Double-sided pouring uses a shrinkage riser set in the core of the casting to supplement the wheel core, avoiding the problem of irregular shrinkage holes on the casting due to the wheel core not being properly supplemented away from the gate during cooling and solidification. In the prior art, the shrinkage riser is set relatively high, almost 1 / 3-2 / 3 of the height of the rim. For example, the low pressure casting mold structure for an aluminum alloy wheel hub disclosed in the patent application with the application publication number CN101318213A includes an upper mold, a lower mold and a side mold, and the lower mold is provided with two gates symmetrically distributed on the side edges of the lower mold. During pouring, double-sided pouring can be achieved using the two gates. The above low pressure casting mold structure sets a shrinkage riser to supplement the wheel core position to avoid shrinkage holes at the wheel core position.

[0005] This kind of setting of the shrinkage riser for supplementing has the problems of a large amount of shrinkage liquid for casting the shrinkage riser, a large material waste, and a relatively high casting cost. SUMMARY

[0006] The present application aims to overcome the shortcomings of the prior art and provide a wheel hub casting mold that can reduce the loss of shrinkage liquid for the shrinkage riser and reduce costs.

[0007] Another object of the present application is to provide a wheel hub casting cooling process.

[0008] To achieve the above-mentioned objects, the technical solutions of the present application are as follows:

[0009] A wheel hub casting mold comprises an upper mold, a side mold, a lower mold, and a cooling device, the upper mold, the side mold and the lower mold form a casting cavity after being closed, the side mold is provided with a sprue, the lower mold is provided with a center column arranged upwardly and protruding, and the cooling device is used for cooling the casting cavity to form a wheel hub blank in the casting cavity.

[0010] The cooling device comprises a center cooling structure, an intermediate cooling structure and an outer cooling structure, the center cooling structure is used for cooling the center of the wheel hub blank, the intermediate cooling structure is used for cooling the inner ring of the wheel hub blank, and the outer cooling structure is used for cooling the outer ring and the rim of the wheel hub blank.

[0011] The center cooling structure comprises a center column liquid cooling cavity arranged in the center column and an annular liquid cooling cavity arranged in the upper mold and surrounding the center column.

[0012] The center cooling structure, the intermediate cooling structure and the outer cooling structure are started in sequence in use so that the wheel hub blank is solidified in sequence from the center to the rim.

[0013] As a preferred technical solution of the present application, the center column liquid cooling cavity is provided with a liquid blocking disc, the liquid blocking disc and the top of the center column liquid cooling cavity form a cavity, the liquid blocking disc is provided with an inlet hole and an outlet hole, and the total cross-sectional area of the inlet hole is not less than the total cross-sectional area of the outlet hole. The total cross-sectional area of the inlet hole is not less than the total cross-sectional area of the outlet hole, so that the cooling liquid always maintains a full state during cooling, and the cooling effect is better.

[0014] As a preferred technical solution of the present application, the center cooling structure comprises an inlet pipe, and the outlet of the inlet pipe is arranged opposite to the top of the center column liquid cooling cavity. The outlet of the inlet pipe is arranged at the top of the center column liquid cooling cavity, which can ensure the cooling effect of the top of the center column liquid cooling cavity, and the cooling liquid is scattered along the inner cavity wall after impacting on the top of the center column liquid cooling cavity, so that the cooling liquid is maximally used to take away heat to cool the center column, and the cooling effect of the cooling liquid in the center column liquid cooling cavity is ensured.

[0015] As a preferred technical solution of the present application, the lower mold is provided with a bottom disc closing the center column liquid cooling cavity.

[0016] As a preferred technical solution of the present application, the center column is detachably assembled on the lower mold.

[0017] As a preferred technical solution of the present application, the upper mold is provided with a cover for packaging the annular liquid cooling cavity, and the cover is provided with a cooling liquid inlet pipe and a cooling liquid outlet pipe.

[0018] The outer cooling structure comprises an outer ring liquid cooling structure and a rim cooling structure, the rim cooling structure comprises a chill block arranged on the side mold and a wind cooling pipe for air cooling the rim and a mist cooling pipe for mist cooling the rim.

[0019] The chill block is arranged on the side mold at a position corresponding to the connection between the rim and the spoke. The chill block is used to accelerate the cooling speed of the hot spot at the connection between the rim and the spoke. Due to the functional requirements of the hub structure, the wall thickness of each part of the hub is uneven. During the cooling process of the casting, the part with a thicker wall thickness cools slower, and the part with a thinner wall thickness cools faster, resulting in uneven cooling speed of each part of the same casting, which may cause problems such as shrinkage, porosity or cracking of the part with a thin wall. In order to avoid such phenomenon, a chill block is arranged at the position of the mold corresponding to the part with a thicker wall thickness (i.e. the connection between the rim and the spoke), which is used to accelerate the cooling speed of the part with a thicker wall thickness, shorten the time difference with the part with a thinner wall thickness, promote the sequential solidification of the casting from the center to the rim, and improve the mechanical properties and yield of the casting.

[0020] A hub casting cooling process using the above hub casting mold. During the cooling process, the center cooling structure, the intermediate cooling structure and the outer cooling structure are started in sequence at intervals, so that the hub blank is sequentially solidified from the center to the rim.

[0021] As a preferred technical solution of the present application, when the center cooling structure is started, the cooling liquid is first introduced into the annular liquid cooling cavity of the upper mold, and then the cooling liquid is introduced into the center column liquid cooling cavity of the lower mold.

[0022] As a preferred technical solution of the present application, the outer cooling structure comprises an outer ring liquid cooling structure and a rim cooling structure, the rim cooling structure comprises a chill block arranged on the side mold and a wind cooling pipe for air cooling the rim and a mist cooling pipe for mist cooling the rim, and the hub casting cooling process comprises the following steps:

[0023] 1) After the casting cavity is poured, the cooling liquid is introduced into the annular liquid cooling cavity of the upper mold after a delay of 10-20s for 60-80s;

[0024] 2) After the casting cavity is poured, the cooling liquid is introduced into the center column liquid cooling cavity of the lower mold after a delay of 20-30s for 130-170s;

[0025] 3) After the casting cavity is poured, the inner ring of the hub blank is cooled by the intermediate cooling structure after a delay of 30-50s for 90-110s;

[0026] 4) After the casting cavity is poured, the outer ring of the hub blank is cooled by the outer ring liquid cooling structure after a delay of 50-70s for 30-50s, and the rim is cooled by the mist cooling pipe for 50-70s.

[0027] 5) Casting cavity pouring is completed, and the rim is cooled for 110-130s through the air cooling pipe after delaying for 80-100s.

[0028] Beneficial effects:

[0029] 1、 The present application can realize reliable feeding through the gate by controlling the whole casting solidification sequence on the basis of reducing or eliminating the feeding riser through reforming the original feeding riser of the casting mold core part and additionally setting the liquid cooling structure and setting the liquid cooling structure in the center column.

[0030] 2、 The present application can make the wheel core far from the gate cool and solidify prior to the spoke and the rim through the strong cooling mode, completely change the casting solidification sequence, and the hub casting no longer needs to set too high feeding riser or even does not need the feeding riser to complete the casting, and the casting qualified rate is higher, and the shrinkage hole almost does not appear. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description.

[0032] Figure 1 It is a cross-sectional structure schematic diagram of the hub casting mold of the present application;

[0033] Figure 2 It is Figure 1 It is a local enlarged schematic diagram of A;

[0034] Figure 3 It is Figure 1 It is a local enlarged schematic diagram of B;

[0035] Figure 4 It is a structure schematic diagram of embodiment 3;

[0036] Figure 5 It is Figure 4 It is a local enlarged schematic diagram of C;

[0037] Explanation of reference numerals in the attached drawings: 1. Upper mold; 12. Center tube; 13. Venting particle; 2. Side mold; 21. Chill; 3. Lower mold; 4. Upper mold core; 41. Annular liquid cooling cavity; 411. Coolant inlet pipe; 412. Coolant outlet pipe; 413. Cap; 5. Center column; 50. Liquid inlet pipe; 51. Liquid baffle plate; 52. Base plate; 53. Liquid outlet pipe; 6. Clearance; 7. Gate; 81. Mist cooling pipe; 82. Air cooling pipe; 821. Small hole; 83. Intermediate cooling structure; 84. Outer ring liquid cooling structure; 91. Ejector plate; 92. Ejector connecting plate; 93. Ejector column; 94. Upper mold connecting column; 95. Upper mold connecting plate. Detailed Implementation

[0038] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0039] In wheel hub casting molds using the double-sided casting method, during the cooling and solidification process, because the wheel core wall is thicker than the wheel spokes, the wheel spokes, which serve as the feeding channel for the wheel core, often solidify before the wheel core. This results in the wheel core not receiving feeding from the gate, leading to shrinkage porosity and other defects.

[0040] Existing technologies mostly address the above problems through two methods: 1. Thickening the spoke wall so that it solidifies later than the wheel hub; however, thickening the spoke wall not only increases the production cost of the wheel hub but also increases the weight of the tire, which is not conducive to creating lightweight tires. 2. Setting a riser at the wheel hub to compensate for the shrinkage of the wheel hub. The wheel hub does not need to be compensated through the spokes, so the spoke wall thickness can be set to be thinner. However, setting a compensation riser at the wheel hub to compensate for the shrinkage requires the riser to be large, ensuring that the riser solidifies after the wheel hub to play its compensation role. Therefore, the compensation riser requires a large amount of compensation fluid for casting, resulting in significant material waste and relatively high casting costs.

[0041] This invention changes the core structure of the casting by using strong cooling on the wheel core, which is far from the gate, to allow it to cool and solidify before the spokes, thus completely changing the solidification sequence and eliminating the need for feeding risers to complete the casting process.

[0042] Example 1:

[0043] like Figures 1-3 The wheel hub casting mold shown includes an upper mold 1, a side mold 2, a lower mold 3, and a cooling device; wherein, after the upper mold 1, the side mold 2, and the lower mold 3 are closed, a casting cavity is formed, and the cooling device is used to cool the casting cavity to form a wheel hub blank within the casting cavity; the cooling device includes a central cooling structure, an intermediate cooling structure 83, and an external cooling structure.

[0044] The upper die 1 is centrally hollowed, and the upper die core 4 is arranged at the centrally hollowed part of the upper die 1. The edge of the upper die core 4 is provided with a stepped mounting portion, and the edge of the centrally hollowed part of the upper die 1 is provided with a boss which is assembled with the mounting portion. The boss and the mounting portion are connected by bolts to achieve detachable connection of the upper die core 4 and the upper die 1. The upper die core 4 is internally provided with an annular liquid cooling cavity 41. An upper cover 413 is arranged above the annular liquid cooling cavity 41 to encapsulate the annular liquid cooling cavity 41 to form a closed cavity. The upper end of the annular liquid cooling cavity 41 is provided with a groove, and the lower end of the upper cover 413 is provided with a raised edge which is matched with the groove. The upper cover 413 and the annular liquid cooling cavity 41 are assembled by matching the groove and the raised edge to form an annular liquid cooling cavity. The upper cover 413 is provided with a cooling liquid inlet pipe 411 and a cooling liquid outlet pipe 412. During cooling, the cooling liquid enters the annular liquid cooling cavity from the cooling liquid inlet pipe 411 and is discharged from the cooling liquid outlet pipe 412. When the upper die 1 is matched with the side die 2 and the lower die 3 to form a casting cavity, the annular liquid cooling cavity 41 surrounds the upper part of the center column 5. During cooling, the annular liquid cooling cavity 41 is used to cool the upper part of the center position of the casting cavity.

[0045] The side die 2 is provided with two left-right symmetrical sprues 7. The opening of the sprue 7 is arranged at a position corresponding to the rim of the casting, and the lowest end of the opening of the sprue 7 is arranged at a position corresponding to the connection between the rim and the spoke. The bottom end of the sprue 7 is curved, and the height of the opening of the bottom end of the sprue 7 is lower than the middle part of the bottom end. During solidification and cooling, the sprue 7 can provide gravity feeding for the hot spot, and the hot spot is effectively fed, so that the connection between the rim and the spoke is not prone to shrinkage and porosity defects.

[0046] The connection between the rim and the spoke, i.e. the hot spot, has a relatively thick wall thickness and a slow cooling speed after pouring. The wall thickness of the spoke and the rim adjacent to the hot spot is relatively thin and has a fast cooling speed. When the pouring mode is center bottom pouring, the spoke as a feeding channel cools before the hot spot, and the hot spot cannot be fed, which causes shrinkage and porosity defects, so that the mechanical properties of the hub casting are not high, the quality is poor, and the scrap rate is high. The sprues of the prior art are mostly arranged on the lower die, and the hot spot cannot be gravity fed, so the feeding effect is not ideal. The arrangement of the sprue 7 solves the above problems.

[0047] The sprue 7 is connected with a liquid lifting pipe, and the arrangement of the double-sided sprue makes the pouring speed faster, which can improve the production speed of the hub. The side die 2 is also uniformly provided with a plurality of chills 21 which are arranged at positions corresponding to the connection between the rim and the spoke. The number of the chills 21 is the same as the number of the spokes. The chills 21 can accelerate the cooling of the hot spot of the casting, shorten the time difference between the cooling of the hot spot and other parts with thin wall thickness, promote the sequential solidification of the casting from the center to the rim direction, avoid shrinkage and porosity defects of the casting, and improve the mechanical properties and yield of the casting.

[0048] The lower mold 3 is provided with a center column 5 arranged protruding upward, the center column 5 is detachably connected with the lower mold 3, a connecting part is arranged at the lower end of the center column 5, and the connecting part is detachably connected with the lower mold 3 through bolts. The center column 5 is hollowed in the inside to form a center column liquid cooling cavity, a liquid baffle 51 is fixedly arranged at the top of the center column liquid cooling cavity, the liquid baffle 51 is matched with the cavity wall at the top of the center column liquid cooling cavity, and the liquid baffle 51 forms a cavity together with the top of the center column liquid cooling cavity. A liquid inlet hole and a plurality of liquid outlet holes are arranged on the liquid baffle 51, the liquid inlet hole is arranged at the center of the liquid baffle 51, the liquid outlet holes are uniformly distributed around the liquid inlet hole, and the liquid inlet hole is used for passing the liquid inlet pipe 50. One end of the liquid inlet pipe 50 passes through the liquid inlet hole into the cavity, and the other end is connected with the cooling liquid outlet; the liquid inlet pipe 50 conveys the cooling liquid from the cooling liquid outlet into the cavity. The total cross-sectional area of the liquid inlet hole on the liquid baffle 51 is greater than that of the liquid outlet hole, so that the amount of cooling liquid in the cavity is always sufficient during cooling. The liquid baffle 51 is arranged at a height lower than the highest position of the contact between the lower mold 3 and the center column 5, and the cavity formed by the liquid baffle 51 and the top of the center column liquid cooling cavity is used for cooling the center position of the casting cavity during cooling.

[0049] The center cooling structure is used for cooling the center of the hub blank, and the center cooling structure comprises the center column liquid cooling cavity arranged in the center column 5 and the annular liquid cooling cavity 41 arranged in the upper mold 1.

[0050] The intermediate cooling structure 83 is used for cooling the inner ring of the hub blank. The intermediate cooling structure 83 is an annular liquid cooling ring arranged around the center column and arranged inside the lower mold.

[0051] The outer cooling structure is used for cooling the outer ring and the rim of the hub blank. The outer cooling structure comprises an outer ring liquid cooling structure 84 and a rim cooling structure, and the rim cooling structure comprises the chill 21 arranged on the side mold 2 and the mist cooling pipe 81 used for mist cooling the rim and the air cooling pipe 82 used for air cooling the rim. The outer ring liquid cooling structure 84 is an annular liquid cooling ring arranged around the hot spot below and arranged inside the lower mold. The air cooling pipe 82 is arranged inside the upper mold 1 and extends above the upper mold 1, two air cooling pipes 82 are symmetrically arranged, and the air cooling pipes 82 are arranged opposite to the gate opening position on the inside of the upper mold 1. A plurality of small holes 821 are arranged as air outlets at positions corresponding to the rim on the air cooling pipe 82, and the air cooling pipe 82 outputs cold air to cool the rim. The mist cooling pipe 81 is arranged inside the upper mold 1 and extends above the upper mold 1, a mist outlet of the mist cooling pipe 81 is opposite to a position corresponding to the middle part of the rim and is used for cooling the rim. Two mist cooling pipes 81 are symmetrically arranged, and the mist cooling pipes 81 and the air cooling pipes 82 are uniformly arranged on the inside of the upper mold 1.

[0052] The small original feeding head of the core of the mold still remains, which does not have feeding function and is mainly used for collecting the dross generated in the molding process to avoid the dross from mixing into the casting to affect the mechanical properties.

[0053] The present application realizes reliable feeding through the gate 7 on the basis of reducing the volume of the feeding head by reforming the original feeding head of the core of the mold and additionally arranging the annular liquid cooling cavity 41 and arranging the cooling structure on the center column 5 to control the solidification sequence of the whole casting (sequential solidification from the wheel core to the wheel rim).

[0054] Specifically, the metal liquid in the embodiment is aluminum liquid and is used for casting aluminum alloy wheel hub; additionally, the metal liquid is steel liquid when the wheel hub casting mold in the embodiment is used for casting steel wheel hub; and the metal liquid is magnesium liquid when the wheel hub casting mold in the embodiment is used for casting magnesium alloy wheel hub; the composition of the metal liquid is specifically prepared according to the properties of the wheel hub to be cast.

[0055] Embodiment 2:

[0056] The difference between the embodiment and embodiment 1 mainly lies in that in the embodiment, the through hole penetrating through the upper mold core 4 is arranged at the center position of the upper mold core 4, and the center pipe 12 is arranged in the through hole and is used for exhausting gas during the casting process of the casting cavity. The honeycomb hole-shaped exhaust particle 13 made of stainless steel is arranged at the lower end of the through hole. The exhaust particle 13 solves the problem of difficulty in cleaning and replacing the lower end of the center pipe 12 blocked by the metal liquid.

[0057] The middle part of the connection between the upper mold core 4 and the upper mold 1 is provided with the empty space 6, and the middle part of the connection between the lower mold 3 and the center column 5 is provided with the empty space 6. The middle part of the stepped edge of the upper mold core 4 is provided with the groove. After the upper mold core 4 is assembled with the upper mold 1, the groove and the central boss of the upper mold 1 form the empty space 6. The lower part of the outer side of the center column 5 is provided with the stepped protrusion, and the lower mold 3 is provided with the inner recess matched with the stepped protrusion. The groove is arranged below the connection position of the center column 5 and the lower mold 3 to the lower part of the stepped protrusion, and the groove forms the empty space 6 after being assembled and connected with the lower mold 3. Because there are small gaps at the connection positions of the mold, the gaps also have the function of exhausting gas in the casting process. The arrangement of the empty space strengthens the function of exhausting gas at the connection gaps. At the same time, the arrangement of the empty space makes the cooling process more targeted. The middle position of the mold which does not need to be cooled is provided with the empty space to avoid heat exchange. The upper mold empty space can avoid heat exchange between the annular liquid cooling cavity 41 and the upper mold 1, the lower mold empty space can avoid heat exchange between the center column liquid cooling cavity and the lower mold 3, and unnecessary heat loss is reduced.

[0058] The bottom end of the center column 5 is provided with a bottom disc 52, which is matched with the bottom opening of the center column liquid cooling cavity, and the bottom disc 52 is used to close the bottom of the center column liquid cooling cavity. The bottom disc 52 is provided with a through hole for the inlet liquid pipe 50 and the outlet liquid pipe 53 to pass through.

[0059] The inlet liquid pipe 50 penetrates through the through hole of the bottom disc 52 and the inlet hole of the liquid blocking disc 51 into the top chamber of the center column liquid cooling cavity. The outlet of the inlet liquid pipe 50 is arranged at the top of the center column liquid cooling cavity and is away from the top end of the center column liquid cooling cavity by a certain distance. The outlet of the inlet liquid pipe 50 is opposite to the top end of the center column liquid cooling cavity. This arrangement can make the cooling liquid spread along the cavity wall after impacting on the top of the center column liquid cooling cavity. The flow direction of the cooling liquid is always from top to bottom, which maximizes the use of the cooling liquid to take away heat to cool the center column, and ensures that the cooling effect of the cooling liquid in the center column liquid cooling cavity reaches the best. The total cross-sectional area of the inlet hole on the liquid blocking disc 51 is equal to the total cross-sectional area of the outlet hole, which ensures that the amount of cooling liquid in the chamber always remains full during cooling, and the cooling effect is better.

[0060] The cooling liquid of the center column liquid cooling cavity is output from the inlet liquid pipe 50. The cooling liquid flows from top to bottom in the top chamber of the center column liquid cooling cavity to take away heat, and then flows out from the outlet hole of the liquid blocking disc 51 into the bottom chamber of the center column liquid cooling cavity, and finally flows out from the outlet liquid pipe 53.

[0061] Example 3:

[0062] The difference between this embodiment and example 2 is mainly that, as shown in the figure, Figures 4-5 The exhaust particles 13 are arranged in a circular ring shape. The exhaust particles 13 are arranged at the top of the center column 5. The top of the center column 5 and the upper mold core 4 are both provided with grooves to be clamped and assembled with the exhaust particles 13.

[0063] After the upper mold 1, the side mold 2 and the lower mold 3 are closed, the casting cavity is not provided with a feeding riser. The original feeding riser of the core of the casting mold is reformed. By controlling the solidification sequence of the entire casting, reliable feeding is realized through the sprue 7 on the basis of canceling the feeding riser.

[0064] The cold iron 21 is an external cold iron. The number of cold irons 21 is reduced by 2 compared with the spokes. The connection between the rim where the two sprues are located and the spokes is not provided with a cold iron 21.

[0065] The empty space 6 formed by the lower mold 3 and the center column 5 is arranged below the liquid blocking disc 51.

[0066] Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, any equivalent structure or equivalent process transformation using the content of the specification and drawings of the present application, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

[0067] Example 4:

[0068] A wheel hub casting cooling process, comprising the following steps:

[0069] 1) After the casting cavity pouring is completed, cooling liquid is introduced into the annular liquid cooling cavity 41 of the upper mold for 60s after a delay of 10s;

[0070] 2) After the casting cavity pouring is completed, cooling liquid is introduced into the center column liquid cooling cavity of the lower mold for 130s after a delay of 20s;

[0071] 3) After the casting cavity pouring is completed, the inner ring of the wheel hub blank is cooled by the intermediate cooling structure 83 for 90s after a delay of 30s;

[0072] 4) After the casting cavity pouring is completed, the outer ring of the wheel hub blank is cooled by the outer ring liquid cooling structure 84 for 30s after a delay of 50s, and the rim is cooled by the mist cooling pipe 81 for 50s;

[0073] 5) After the casting cavity pouring is completed, the rim is cooled by the air cooling pipe 82 for 110s after a delay of 80s.

[0074] The present application cools and solidifies from the wheel core far from the sprue, then to the spokes and the rim, without setting a feeding riser to feed the wheel core far from the sprue, and directly feeding from the sprue (during the solidification process, the metal liquid enters the wheel core from the sprue through the spokes of the casting cavity to feed the wheel core). During the cooling process, first, the upper part of the wheel core in the casting cavity is cooled by the annular liquid cooling cavity 41 to prevent the upper part of the wheel core from feeding the lower part when the wheel core is cooled simultaneously, causing shrinkage and porosity in the upper part of the wheel core; then the wheel core is cooled by the center column liquid cooling cavity and the annular liquid cooling cavity 41 (i.e. the center cooling structure); after a certain period of cooling, the wheel core has completed solidification, but the center cooling structure is still cooling, and the center cooling structure begins to radiate to the periphery; then the middle cooling structure 83, which is arranged inside the lower mold and surrounds the center column, cools the middle part of the casting cavity (the junction between the spokes and the wheel core); after a certain period of cooling, the middle part of the casting cavity completes solidification, the middle cooling structure 83 begins to radiate the spokes, promoting the solidification of the spokes; next, the outer ring liquid cooling structure 84 and the mist cooling pipe 81 simultaneously cool the outside of the casting cavity; the outer ring liquid cooling structure 84 surrounds the hot spot and is used to cool the hot spot, and the mist cooling pipe 81 is used to cool the rim far from the sprue; finally, the rim close to the sprue is cooled by the air cooling pipe 82.

[0075] During the entire cooling and solidification process, the casting cavity strictly cools according to the order of solidification from the position far from the sprue first, and then the position close to the sprue, ensuring that each part of the casting in the casting cavity can be effectively fed, avoiding the defects of shrinkage and porosity caused by the feeding channel cooling first.

[0076] Example 5:

[0077] A wheel hub casting cooling process, comprising the following steps:

[0078] 1) After the casting cavity is poured, cooling liquid is introduced into the annular liquid cooling cavity 41 of the upper mold for 70s after a delay of 15s;

[0079] 2) After the casting cavity is poured, cooling liquid is introduced into the center column liquid cooling cavity of the lower mold for 150s after a delay of 25s;

[0080] 3) After the casting cavity is poured, the inner ring of the wheel hub blank is cooled for 100s by the intermediate cooling structure 83 after a delay of 40s;

[0081] 4) After the casting cavity is poured, the outer ring of the wheel hub blank is cooled for 40s by the outer ring liquid cooling structure 84 after a delay of 60s, and the rim is cooled for 60s by the fog cooling pipe 81;

[0082] 5) After the casting cavity is poured, the rim is cooled for 120s by the air cooling pipe 82 after a delay of 90s.

[0083] Example 6:

[0084] A wheel hub casting cooling process, comprising the following steps:

[0085] 1) After the casting cavity is poured, cooling liquid is introduced into the annular liquid cooling cavity 41 of the upper mold for 80s after a delay of 20s;

[0086] 2) After the casting cavity is poured, cooling liquid is introduced into the center column liquid cooling cavity of the lower mold for 170s after a delay of 30s;

[0087] 3) After the casting cavity is poured, the inner ring of the wheel hub blank is cooled for 110s by the intermediate cooling structure 83 after a delay of 50s;

[0088] 4) After the casting cavity is poured, the outer ring of the wheel hub blank is cooled for 50s by the outer ring liquid cooling structure 84 after a delay of 70s, and the rim is cooled for 70s by the fog cooling pipe 81;

[0089] 5) After the casting cavity is poured, the rim is cooled for 130s by the air cooling pipe 82 after a delay of 100s.

[0090] The cooling process controls multiple cooling points and cooling time of the cooling device, so that the molten metal in the casting cavity is solidified gradually from the wheel core to the wheel rim under the mold temperature control, the wheel core is cooled and solidified earlier than the wheel spoke by using the strong cooling mode far from the sprue, the solidification sequence in the casting cavity is completely changed, and the wheel hub casting can be completed without feeding riser. When the wheel core needs to be fed during the wheel core cooling process, the molten metal flows from the wheel spoke into the wheel core for feeding; by analogy, when the wheel spoke is cooled, the molten metal flows from the wheel rim into the wheel spoke for feeding; when the wheel rim is cooled, the molten metal flows from the sprue into the wheel rim for feeding.

[0091] When the casting is solidified, if the temperature field of the casting cavity changes irregularly, the wheel spoke as a feeding channel is relatively thin, the thickness of the wheel hub is unreasonable, and other quality defects are caused. If the cooling speed is too fast and the hot spot area is large, the casting will also cause quality defects. In order to reduce the quality defects of the wheel hub, it is necessary to ensure that the temperature field of the casting cavity is strictly solidified in sequence. Through the wheel hub cooling and solidification process of the cooling process, not only the casting defects such as gas hole and insufficient casting are greatly reduced, but also the mechanical properties of the produced casting are better and the qualified rate is higher.

[0092] The working principle is as follows:

[0093] The top plate 91 is connected with the top column 93 through the top connecting plate 92, and the upper die 1 is connected with the upper die connecting column 94 through the upper die connecting plate 95.

[0094] When starting, the upper die driving device drives the upper die connecting column 94 to push the upper die 1 to descend, and the side die driving device drives the side die 2 to fold to the center, so that the casting mold is accurately and in place. Then, the compressed air is pressed into the holding furnace, so that the molten metal rises along the liquid lifting pipe, the molten metal enters the casting cavity through the sprue 7 and finally fills the cavity, and then the pressure gradually increases, and the pressure is maintained for a certain time.

[0095] Then, the cooling device strictly controls the cooling sequence according to the cooling process of the application to make the casting crystallize and solidify.

[0096] After cooling, the pressure is removed, the side die 2 is retracted first, and then the upper die driving device drives the upper die connecting column 94 to move upwards to drive the wheel hub casting to rise; after rising to a fixed height, the top driving device drives the top column 93 to descend, and at the same time drives the top connecting plate 92 and the top plate 91 connected together to descend, the top plate 91 ejects the wheel hub casting from the cavity, the wheel hub casting is demolded, and the casting is caught by the tray, and the upper die 1 continues to rise, and the casting is demolded.

[0097] It should be pointed out finally that the above embodiments are merely examples for clearly illustrating the present application and are not intended to limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. It is unnecessary and impossible to enumerate all the embodiments. The changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A wheel hub casting cooling process based on a wheel hub casting mold, the mold comprising: an upper mold (1), a side mold (2), a lower mold (3), and a cooling device, the upper mold (1), the side mold (2), and the lower mold (3) forming a casting cavity after being closed, the side mold (2) being provided with a sprue (7), the lower mold (3) being provided with a center column (5) arranged protruding upward, and the cooling device being used for cooling the casting cavity to form a wheel hub blank in the casting cavity; characterized in that the upper mold (1) is centrally provided with an upper mold core (4), the upper mold core (4) being provided with a through hole penetrating the upper mold core (4) at a central position, a center tube (12) being arranged in the through hole for exhausting, and the through hole being provided with an exhaust particle (13) at a lower end; the upper mold core (4) being provided with an empty space (6) at a middle part connected with the upper mold (1), and the lower mold (3) being provided with an empty space (6) at a middle part connected with the center column (5); the cooling device comprising a center cooling structure, an intermediate cooling structure, and an outer cooling structure, the center cooling structure being used for cooling the center of the wheel hub blank, the intermediate cooling structure being used for cooling the inner ring of the wheel hub blank, and the outer cooling structure being used for cooling the outer ring and the rim of the wheel hub blank; the center cooling structure comprising a center column liquid cooling cavity arranged in the center column (5) and an annular liquid cooling cavity (41) arranged in the upper mold (1), the annular liquid cooling cavity (41) being arranged around the center column (5); the outer cooling structure comprising an outer ring liquid cooling structure and a rim cooling structure, the rim cooling structure comprising a chill (21) arranged on the side mold (2), a mist cooling pipe (81) for mist cooling the rim, and a wind cooling pipe (82) for wind cooling the rim; during cooling, the center cooling structure, the intermediate cooling structure, and the outer cooling structure are sequentially started at intervals to make the wheel hub blank solidify from the center to the rim; when the center cooling structure is started, cooling liquid is first introduced into the annular liquid cooling cavity (41) of the upper mold (1) and then into the center column liquid cooling cavity of the lower mold (3); the wheel hub casting cooling process comprising the following steps: 1) after the casting cavity is poured, cooling liquid is introduced into the annular liquid cooling cavity (41) of the upper mold (1) after a delay of 10-20 s for 60-80 s; 2) after the casting cavity is poured, cooling liquid is introduced into the center column liquid cooling cavity of the lower mold (3) after a delay of 20-30 s for 130-170 s; 3) after the casting cavity is poured, the inner ring of the wheel hub blank is cooled by the intermediate cooling structure (83) after a delay of 30-50 s for 90-110 s; 4) after the casting cavity is poured, the outer ring of the wheel hub blank is cooled by the outer ring liquid cooling structure (84) after a delay of 50-70 s for 30-50 s, and the rim is cooled by the mist cooling pipe (81) for 50-70 s; 5) after the casting cavity is poured, the rim is cooled by the wind cooling pipe (82) after a delay of 80-100 s for 110-130 s.

2. A wheel hub casting cooling process as claimed in claim 1, wherein, The center column liquid cooling cavity is provided with a liquid baffle (51), the liquid baffle (51) and the top of the center column liquid cooling cavity form a cavity together, the liquid baffle (51) is provided with a liquid inlet hole and a liquid outlet hole, and the total cross-sectional area of the liquid inlet hole is not less than the total cross-sectional area of the liquid outlet hole.

3. A wheel hub casting cooling process as claimed in claim 1 or 2, characterized in that The center cooling structure comprises a liquid inlet pipe (50), and the outlet of the liquid inlet pipe (50) is arranged opposite to the top of the center column liquid cooling cavity.

4. A wheel hub casting cooling process as claimed in claim 1 or 2, wherein, The lower die (3) is provided with a bottom disc (52) for closing the center column liquid cooling cavity.

5. A wheel hub casting cooling process as claimed in claim 1 wherein, The center column (5) is detachably assembled on the lower die (3).

6. A wheel hub casting cooling process as claimed in claim 1, wherein, The upper die (1) is provided with a cover (413) for encapsulating the annular liquid cooling cavity (41), and the cover (413) is provided with a cooling liquid inlet pipe (411) and a cooling liquid outlet pipe (412).

Images