Low pressure casting mold cooling structure

Abstract

This utility model relates to the field of aluminum alloy wheel casting and discloses a cooling structure for a low-pressure casting mold. It includes an inner cooling ring connected to a water inlet pipe, a strong cooling pipe corresponding to the area of ​​the mold requiring intense cooling, and an outer cooling ring surrounding the inner cooling ring. The outer wall of the inner cooling ring and the inner wall of the outer cooling ring serve as a return water channel for cooling water flow. The outlet of the strong cooling pipe connects to the return water channel, which in turn connects to the return water pipe. This utility model achieves differentiated cooling for specific areas of the mold, improving the problems of shrinkage cavities, porosity, deformation, and cracks in wheel products. The sleeve-type cooling structure effectively improves the high risk of leakage associated with traditional cooling methods. Furthermore, the sleeve-type cooling structure ensures that the low-temperature cooling water entering the cooling structure undergoes pre-heat exchange in the inner cooling ring through the return water channel before entering the strong cooling channel for intense cooling, overcoming the thermal stress caused by excessive temperature differences in the cooling water.

Description

Technical Field

[0001] This utility model relates to the field of aluminum alloy wheel hub casting, and in particular to a cooling structure for low-pressure casting molds. Background Technology

[0002] In the production process of low-pressure cast aluminum alloy wheels, mold temperature control is a key factor in ensuring product quality. The complex structure and significant differences in wall thickness of wheel hubs result in highly uneven heat distribution across different areas of the mold during filling and solidification. To meet process requirements, different locations on the mold (such as thicker sections and critical heat dissipation areas) typically require differentiated cooling intensities to achieve an ideal temperature field distribution and solidification sequence. Currently, low-pressure casting molds commonly employ periodic circulating water cooling systems. However, this traditional cooling method has the following major technical drawbacks, directly affecting the quality and production stability of wheel hub products:

[0003] Mismatch between cooling uniformity and demand: Existing water-cooling structures struggle to provide differentiated cooling for specific areas of the mold, resulting in an unreasonable and unstable temperature field distribution. This can easily lead to internal and external defects in wheel products, such as shrinkage cavities, porosity, deformation, cracks, and even cold shuts. High risk of leakage: Traditional cooling structures have complex piping layouts, typically using a modular processing and assembly method. Under harsh conditions of high pressure, high temperature, and cyclic thermal shock, this structure is prone to leakage, directly damaging the mold and affecting production safety. It can also lead to cooling failure, exacerbating product quality issues. Excessive temperature difference in cooling water causes thermal stress: Directly introducing cooler cooling water into the mold creates a huge temperature difference with the high-temperature mold body. This drastic localized cooling generates excessive thermal stress inside the mold, reducing its lifespan. At the same time, drastic temperature fluctuations also interfere with the stability of the wheel's solidification process, hindering the acquisition of a uniform and dense metallographic structure. Utility Model Content

[0004] The purpose of this utility model is to provide a cooling structure for low-pressure casting molds to address the above-mentioned problems, thereby solving the problems that existing cooling structures cannot meet the differentiated cooling needs of molds, have a high risk of water leakage, and cause thermal stress due to excessive temperature difference of cooling water.

[0005] The technical solution adopted in this utility model is as follows:

[0006] A cooling structure for a low-pressure casting mold includes a cooling inner ring connected to a water inlet pipe. The cooling inner ring is provided with a strong cooling pipe corresponding to the area of ​​the mold requiring strong cooling. The strong cooling pipe is a protruding structure that connects to the cooling inner ring. A cooling outer ring is fitted around the cooling inner ring. A sealed cooling chamber is opened inside the cooling outer ring. The cooling inner ring is placed inside the cooling chamber. The outer wall of the cooling inner ring and the inner wall of the cooling outer ring serve as a return water channel for cooling water circulation. The outlet of the strong cooling pipe is connected to the return water channel, and the return water channel is connected to a return water pipe.

[0007] Preferably, the inlet pipe and the return pipe are in the form of a sleeve structure, wherein the inner pipe is the inlet pipe and the outer pipe is the return pipe.

[0008] Preferably, a support fin is provided between the inner cooling ring and the outer cooling ring. The support fins are spaced apart on the outer circumferential surface of the inner cooling ring and are uniformly fixed in the radial direction. The outer edge of the support fins is connected to the outer cooling ring.

[0009] Preferably, both the inner and outer cooling rings are double-layered annular structures, with the upper and lower annular structures connected by a connecting pipe, which is connected to a forced cooling pipe.

[0010] Preferably, the connecting pipe is radially offset from the water inlet pipe to extend the flow path of the low-temperature cooling water within the cooling inner ring.

[0011] Preferably, the cooling outer ring is an integrally cast structure.

[0012] The beneficial effects of this utility model are as follows: By setting up a strong cooling pipe that connects to the inner cooling ring, this utility model achieves differentiated cooling for specific areas of the mold, solving the problem that traditional cooling methods provide essentially the same cooling intensity for all areas of the mold, failing to meet the strong or weak cooling requirements of different parts of the wheel hub. This also improves the problem of defects such as shrinkage cavities, porosity, deformation, and cracks in wheel hub products. Simultaneously, the sleeve-structured cooling structure of this utility model effectively mitigates the high risk of water leakage in traditional cooling methods, improving the cooling structure's ability to withstand harsh conditions such as high pressure, high temperature, and cyclic thermal shock, ensuring mold and production safety. Furthermore, the sleeve-structured cooling structure ensures that the low-temperature cooling water entering the cooling structure undergoes pre-heat exchange in the inner cooling ring through the return water channel before entering the strong cooling channel for strong cooling, and then re-enters the return water channel for conventional cooling of the mold. This satisfies the differentiated cooling needs of the mold while overcoming the thermal stress caused by excessive cooling water temperature differences. Attached Figure Description

[0013] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0014] Figure 1This is a three-dimensional structural diagram of the present invention in use.

[0015] Figure 2 for Figure 1 Exploded view.

[0016] Figure 3 This is a cross-sectional view of the present invention.

[0017] Figure 4 This is a flowchart illustrating the manufacturing process of this utility model.

[0018] In the diagram: 10--Cooling inner ring; 11--Water inlet pipe; 12--Forced cooling pipe; 121--Water outlet; 13--Support fins; 20--Cooling outer ring; 21--Return water channel; 22--Return water pipe; 23--Transition sealing ring; 30--Connecting pipe; 40--Mold; 50--Sand mold; 51--Sand mold cavity. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0020] like Figure 1-4 As shown, a low-pressure casting mold cooling structure includes a cooling inner ring 10 connected to a water inlet pipe 11. A strong cooling pipe 12 is provided in the strong cooling area of ​​the mold 40, corresponding to the cooling inner ring 10. The strong cooling pipe 12 is a protruding structure connecting the cooling inner ring 10. A cooling outer ring 20 is sleeved around the cooling inner ring 10, forming a sleeve-type cooling structure. Specifically, a sealed cooling chamber is formed inside the cooling outer ring 20. The cooling inner ring 10 is disposed within the cooling chamber. The outer wall of the cooling inner ring 10 and the inner wall of the cooling outer ring 20 serve as a return water channel 21 for cooling water flow. The outlet 121 of the strong cooling pipe 12 connects to the return water channel 21, and the return water channel 21 connects to a return water pipe 22.

[0021] In use, the cooling structure with the sleeve is assembled on the mold 40, and the strong cooling pipe 12 is arranged to correspond to the area of ​​the mold 40 that needs strong cooling. Cooling water enters the inner cooling ring 10 through the inlet pipe 11 and is strongly cooled to the area of ​​the mold 40 that needs strong cooling through the strong cooling pipe 12. The cooling water that has completed strong cooling enters the return water channel 21 between the inner cooling ring 10 and the outer cooling ring 20 through the outlet 121 of the strong cooling pipe 12 to continue to perform conventional cooling on the mold 40, and is finally discharged through the return water pipe 22. This embodiment achieves differentiated cooling of specific areas of the mold 40 by setting up a strong cooling pipe 12 that connects to the inner cooling ring 10. This solves the problem that traditional cooling methods provide essentially the same cooling intensity to all areas of the mold 40, failing to meet the strong or weak cooling requirements of different parts of the wheel hub. It also improves the problem of defects such as shrinkage cavities, porosity, deformation, and cracks in wheel hub products. At the same time, the sleeve-structured cooling structure in this embodiment effectively improves the high risk of water leakage in traditional cooling methods and enhances the cooling structure's ability to withstand harsh conditions such as high pressure, high temperature, and periodic thermal shock, ensuring the safety of the mold 40 and production. In addition, the sleeve-structured cooling structure allows the low-temperature cooling water entering the cooling structure to undergo pre-heat exchange in the inner cooling ring 10 through the return water channel 21 before entering the strong cooling channel for strong cooling, and then entering the return water channel 21 for conventional cooling of the mold 40. This satisfies the differentiated cooling requirements of the mold 40 while overcoming the thermal stress caused by excessive cooling water temperature differences.

[0022] As a preferred embodiment, such as Figure 3 As shown, the inlet pipe 11 and the return pipe 22 are in a sleeve structure, with the inlet pipe 11 being the internal pipe and the return pipe 22 being the external pipe. The sleeve structure reduces the number of pipe installation locations, simplifies pipe configuration, and avoids problems such as pipe interference.

[0023] Preferably, a support fin 13 is provided between the inner cooling ring 10 and the outer cooling ring 20. The support fins 13 are spaced apart on the outer circumferential surface of the inner cooling ring 10 and are uniformly fixed radially. The outer edge of the support fins 13 is connected to the outer cooling ring 20. The support fins 13 serve two purposes: firstly, they act as a support and positioning component for the inner cooling ring 10 within the outer cooling ring 20, ensuring that the inner cooling ring 10 remains centered within the outer cooling ring 20 and that the return water channel 21 remains unobstructed; secondly, the support fins 13 effectively improve the heat exchange efficiency between the inner cooling ring 10 and the outer cooling ring 20, enabling rapid temperature increase of the low-temperature cooling water.

[0024] Preferably, both the inner cooling ring 10 and the outer cooling ring 20 are double-layered annular structures, connected vertically by a connecting pipe 30, which is connected to the forced cooling pipe 12. In use, low-temperature cooling water enters the lower inner cooling ring 10 through the inlet pipe 11, where it first exchanges heat with the cooling water in the return water channel 21, preheating the low-temperature cooling water. The preheated cooling water then enters the forced cooling pipe 12 through the connecting pipe 30 to provide forced cooling to the areas of the mold 40 requiring strong cooling. The cooled water, having completed forced cooling, enters the return water channel 21 between the inner cooling ring 10 and the outer cooling ring 20 through the outlet 121 of the forced cooling pipe 12, continuing to provide conventional cooling to the mold 40, and finally exits through the return water pipe 22.

[0025] This embodiment employs a double-layered annular cooling structure, where the low-temperature cooling water entering the inner cooling ring 10 is heated by the heat of the mold 40 itself before participating in the cooling and cooling of the mold 40. This avoids thermal stress caused by excessive temperature differences and extends the service life of the mold 40. Simultaneously, it avoids the problem of drastic temperature fluctuations interfering with the stability of the wheel hub solidification process, ensuring the casting quality of the product. Furthermore, this embodiment utilizes the heat of the mold 40 itself to heat the low-temperature cooling water, eliminating the need for a heating device, further simplifying the structural configuration, and achieving the goal of environmental protection and energy conservation.

[0026] Preferably, the connecting pipe and the water inlet pipe 11 are radially offset to extend the flow path of the low-temperature cooling water in the cooling inner ring 10, and to prevent the low-temperature cooling water entering the cooling inner ring 10 from entering the strong cooling pipe 12 too early, which would cause poor cooling to the mold 40.

[0027] Preferably, the cooling outer ring 20 is an integrally cast structure, which further reduces the risk of water leakage.

[0028] like Figure 4 As shown, the preferred embodiment of the method for manufacturing the cooling structure of the low-pressure casting mold 40 includes the following steps:

[0029] S1. Pre-assembly of the support frame: Several support fins 13 are uniformly fixed radially on the outer circumferential surface of the welded inner cooling ring 10, serving as the support frame for the water return channel 21 of the outer cooling ring 20.

[0030] S2. Transition sealing ring 23 forming: A ductile metal strip (preferably a low-carbon steel strip) is continuously wound and wrapped around the outer edge of the support fin 13. The beginning and end seams of the metal strip are sealed and connected by welding to form a cylindrical sealing ring that fits tightly with the outer contour of the support fin 13.

[0031] S3, Sand casting 50mm:

[0032] ① Sand mold 50 preparation: Based on the outer dimensions of the sealing ring, a split sand mold 50 is made, and the core for forming the inlet and outlet water pipes and connecting pipes 30 is pre-embedded in the sand mold cavity 51;

[0033] ② Assembly and positioning: Place the cooling inner ring 10 assembly with sealing ring on the lower sand mold 50, ensuring that the core of the inlet and outlet water pipes and connecting pipes is aligned with the corresponding water channel position;

[0034] ③ Casting and molding: After the mold is closed, molten metal (preferably cast iron HT250) is poured in. The molten metal fills the cavity space between the sealing ring and the sand mold 50. After cooling and solidification, a cooling outer ring 20 is formed that is metallurgically combined with the transition sealing ring 23 which is positioned and supported by the support fins 13. The water inlet pipe 11 and the water return pipe 22 are connected to the cooling water channel.

[0035] The cooling structure of mold 40 made using this method has an outer cooling ring 20 that is integrally cast and molded. During the casting process, it achieves fusion of the metal liquid phase with the transition sealing ring 23, eliminating the assembly interface and fundamentally eliminating the sealing failure problem caused by the separate assembly of traditional cooling structures, thus completely preventing water leakage. This cooling structure, after 1000 thermal cycles under 350℃ conditions, exhibited a leakage rate of 0%, significantly improving sealing performance compared to the >5% leakage rate of traditional cooling structures. Furthermore, this invention employs an inner and outer jacket design with double layers, allowing low-temperature cooling water to undergo pre-heat exchange in the inner cooling ring 10 via the return water channel 21. This raises the water temperature to 35-40℃ before it enters the strong cooling channel to provide strong cooling to the areas of the mold 40 requiring it. The water then enters the return water channel 21 between the inner and outer cooling rings 10 for conventional cooling of the mold 40. This design meets the diverse cooling needs of the mold 40 while overcoming the thermal stress caused by excessive temperature differences in the cooling water. It also avoids thermal shock cracks caused by sudden localized cooling of the mold 40, significantly extending the service life of the cooling structure. This allows the all-metal seamless cooling structure to have the same lifespan as the mold 40 body, and prevents drastic temperature fluctuations from interfering with the stability of the wheel hub solidification process, ensuring the quality of the product casting.

[0036] The above-disclosed embodiments are merely specific examples of this utility model, but this utility model is not limited thereto. For those skilled in the art, any modifications made without departing from the principle of this utility model should be considered as protected by this utility model.

Claims

1. A cooling structure for a low-pressure casting mold, characterized in that: The cooling inner ring (10) is connected to a water inlet pipe (11). The cooling inner ring (10) is provided with a strong cooling pipe (12) corresponding to the strong cooling requirement area of ​​the mold (40). The strong cooling pipe (12) is a protruding structure that connects to the cooling inner ring (10). The cooling inner ring (10) is surrounded by a cooling outer ring (20). A closed cooling chamber is opened in the cooling outer ring (20). The cooling inner ring (10) is set in the cooling chamber. The outer wall of the cooling inner ring (10) and the inner wall of the cooling outer ring (20) serve as a return water channel (21) for cooling water flow. The outlet (121) of the strong cooling pipe (12) is connected to the return water channel (21). The return water channel (21) is connected to the return water pipe (22).

2. The cooling structure for a low-pressure casting mold according to claim 1, characterized in that: The inlet pipe (11) and the return pipe (22) are in the form of a sleeve structure, wherein the internal pipe is the inlet pipe (11) and the external pipe is the return pipe (22).

3. The cooling structure for a low-pressure casting mold according to claim 1, characterized in that: A support fin (13) is provided between the inner cooling ring (10) and the outer cooling ring (20). The support fin (13) is spaced apart on the outer circumferential surface of the inner cooling ring (10) and is uniformly fixed in the radial direction. The outer edge of the support fin (13) is connected to the outer cooling ring (20).

4. The cooling structure for a low-pressure casting mold according to claim 1, characterized in that: The inner cooling ring (10) and the outer cooling ring (20) are both double-layered ring structures. The upper and lower ring structures are connected by a connecting pipe (30), which is connected to the strong cooling pipe (12).

5. The cooling structure for a low-pressure casting mold according to claim 4, characterized in that: The connecting pipe (30) and the water inlet pipe (11) are radially offset to extend the flow path of the low-temperature cooling water in the cooling inner ring (10).

6. The cooling structure for a low-pressure casting mold according to claim 1, characterized in that: The cooling outer ring (20) is an integrally cast structure.

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