Improved sand mold combination for casting

Abstract

The improved sand mold combination for casting comprises an upper sand mold and a lower sand mold which are made of sand materials, the upper sand mold comprises an upper mold plate and an upper mold core which is arranged on the bottom face of the upper mold plate and protrudes downwards, and the lower sand mold comprises a lower mold plate, a front mold wall, a rear mold wall, a left mold wall, a right mold wall and a mold bottom wall, and the front mold wall, the rear mold wall, the left mold wall, the right mold wall and the mold bottom wall are connected to the lower mold plate. A feeding port and an overflow port are formed in the upper mold plate, a pouring runner is arranged on the side, close to the front mold wall, of the lower mold plate, one end of the pouring runner is connected with the feeding port, and the other end of the pouring runner is connected with the casting cavity; the wall thickness of the front mold wall, the wall thickness of the rear mold wall, the wall thickness of the left mold wall and the wall thickness of the right mold wall are basically the same, and a left groove and a right groove are formed in the left mold wall and the right mold wall respectively; the device further comprises a left cold iron block and a right cold iron block. The shape of the mold bottom wall and the shape of the upper mold core are arranged according to the shape of the bottom face of a casting component, and the wall thickness of the mold bottom wall is larger than the wall thickness of the front mold wall, the wall thickness of the rear mold wall, the wall thickness of the left mold wall and the wall thickness of the right mold wall.

Description

Technical Field

[0001] This invention relates to the field of sand mold technology, and in particular to an improved sand mold assembly for casting. Background Technology

[0002] In low-pressure die casting technology for wheel hubs, the manufacturing precision and quality of the casting molds play a crucial role in the quality of the wheel hub products. Some casting mold components, such as side mold castings, are manufactured using sand casting. Therefore, the manufacturing quality of the sand molds is critical to the quality of the casting mold components. To improve the casting quality of wheel hub side molds, the applicant previously proposed a sand mold assembly for casting wheel hub side molds, publication number CN115958159A. The sand mold assembly includes an upper sand mold and a lower sand mold. A downwardly protruding core is formed on the upper sand mold. The lower sand mold is roughly bowl-shaped and includes a left longitudinal cavity wall, a right longitudinal cavity wall, a front transverse cavity wall, a rear transverse cavity wall, and a cavity bottom wall. The left longitudinal cavity wall, right longitudinal cavity wall, front transverse cavity wall, rear transverse cavity wall, and cavity bottom wall form an upward-opening concave cavity. When the upper and lower sand molds are closed together, the core is inserted into the concave cavity. A [missing information - likely a design element] is provided on the left longitudinal cavity wall. A first lower riser socket with an upward opening is used to replenish the casting cavity with molten casting. A liquid inlet channel is provided on the wall of the upper sand mold located on the left side of the core, and a pair of second upper riser channels, positioned front to back, are provided on the wall of the upper sand mold located on the right side of the core. These second upper riser channels penetrate downwards through the bottom wall of the upper sand mold. The advantage of this design is that the first lower riser socket and the second upper riser channels, which are located on the later-solidified casting portions close to the left and right longitudinal cavity walls, can promptly replenish the molten casting, reducing defects such as shrinkage cavities and porosity in the cast wheel hub side mold castings. Practical verification shows that while this technology improves the casting quality of wheel hub side mold castings to some extent, there is still room for improvement in processing speed and manufacturing precision. Summary of the Invention

[0003] To further improve upon the shortcomings of existing technologies, this invention proposes an improved sand mold assembly for casting, comprising an upper sand mold and a lower sand mold made of sand. The upper sand mold includes an upper template and an upper mold core protruding downwards from the bottom surface of the upper template. The lower sand mold includes a lower template and a front mold wall, a rear mold wall, a left mold wall, a right mold wall, and a bottom mold wall connected to the lower template. The front mold wall, rear mold wall, left mold wall, right mold wall, and bottom mold wall define a lower mold cavity capable of accommodating the upper mold core. When the upper and lower sand molds are combined, a casting cavity for casting components is formed between the upper mold core and the lower mold cavity. An inlet and an overflow outlet are provided on the upper template, and a gating channel is provided on the lower template near the front mold wall, one end of which is connected to the inlet. One end is connected to the casting cavity, the overflow port is arranged near the rear mold wall and at least part of the overflow port is connected to the casting cavity; characterized in that the wall thickness of the front mold wall, rear mold wall, left mold wall and right mold wall is basically the same, a left groove and a right groove are respectively provided on the left mold wall and the right mold wall, the left groove and the right groove are connected to the casting cavity, and also includes a left chill block and a right chill block, the left chill block is arranged in the left groove and the inner side of the left chill block is flush with the wall surface of the left mold wall, the right chill block is arranged in the right groove and the inner side of the right chill block is flush with the wall surface of the right mold wall, the shape of the mold bottom wall is arranged according to the shape of the bottom surface of the casting component, and the wall thickness of the mold bottom wall and the upper mold core is greater than the wall thickness of the front mold wall, rear mold wall, left mold wall and right mold wall.

[0004] The upper sand mold is a component manufactured through 3D printing. The upper template and the upper mold core, along with the aforementioned pipe mold core, are integrally formed. The sand used in its manufacture is a mixture of high-temperature resistant quartz sand and furan resin, resulting in both fast molding speed and high structural strength. Due to the use of a high-strength 3D printing process, the thickness of the upper template can be between 28mm and 50mm, significantly reducing the material consumption of the sand mold. Furthermore, to facilitate the pouring of molten metal, the height of the inlet and overflow ports on the upper template is higher than the thickness of the upper template itself.

[0005] The lower sand mold is also a component made by three-dimensional printing. The thickness of the lower mold template and the front mold wall, rear mold wall, left mold wall, right mold wall and bottom mold wall are greatly reduced. The shapes of the front mold wall, rear mold wall, left mold wall, right mold wall and bottom mold wall that form the lower mold cavity can be made according to the shape of the casting component. This not only reduces the use of manufacturing materials, but also facilitates the rapid heat dissipation of the casting.

[0006] The upper mold core is a component that can extend into the lower mold cavity. The outer surface of the upper mold core, the inner surface of the lower mold cavity, and part of the lower surface of the upper mold template form the casting cavity. There are two implementations of the upper mold core: one is a wall structure that changes shape with the lower surface, and the other is a solid structure.

[0007] The front mold wall, rear mold wall, left mold wall, and right mold wall have basically the same thickness, excluding the left and right chill blocks. Due to manufacturing deviations, the thickness of each wall may have certain manufacturing errors, but this has virtually no impact on the manufacturing, forming, and heat dissipation of the cast parts.

[0008] The mold bottom wall is a wall component located at the bottom of the casting cavity. During the casting process, the weight of the molten metal is mainly supported by the mold bottom wall. In addition, after the molten metal enters from the feed port, it flows through the casting cavity between the mold bottom wall and the upper mold core to the overflow port. This flow channel is relatively longer than the flow channels on both sides, and this flow channel corresponds to the main appearance surface or functional surface of the cast component. Feeding it helps to improve the forming quality of the component.

[0009] According to the above technical solution, compared with the prior art, the beneficial technical effects of the present invention are as follows: First, setting the wall thickness of the mold bottom wall and the upper mold core to be greater than the wall thickness of the front mold wall, rear mold wall, left mold wall, and right mold wall not only enhances the structural strength of the mold bottom wall to support the casting components, but also reduces the heat dissipation rate of the mold bottom wall and the upper mold core, thus slowing down the condensation rate of the molten metal between them. This is beneficial for the molten metal to flow smoothly from the inlet to the overflow port during pouring, and after pouring, the molten metal remaining in the inlet and overflow port can also fully compensate for the shrinkage of the wall between the mold bottom wall and the upper mold core. This is advantageous. Firstly, it improves the forming quality of cast components. Secondly, by setting left and right grooves on the left and right mold walls respectively, and setting left and right chill blocks in the left and right grooves, the left and right chill blocks can quickly absorb heat, allowing the molten metal filling the space between the left and right mold walls and the upper mold core to cool and solidify rapidly. The molten metal in the feed port and overflow port concentrates to fully compress the wall between the bottom mold wall and the upper mold core. This not only improves the forming quality of the main molding walls of the cast components, but also increases the cooling and forming speed of the cast components, thereby improving the overall processing efficiency.

[0010] Because of the above-mentioned features and advantages, this invention can be applied to improved casting sand mold assemblies. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the axial structure of the improved sand mold assembly for casting;

[0012] Figure 2 This is a top view structural diagram of the improved sand mold assembly for casting;

[0013] Figure 3 yes Figure 2 Schematic diagram of the cross-sectional structure along the AA direction;

[0014] Figure 4 This is an exploded structural diagram of an improved sand mold assembly for casting.

[0015] Figure 5 This is a schematic diagram of the axial side structure of the upper sand mold;

[0016] Figure 6 This is a schematic diagram of the axial structure of the lower sand mold. Detailed Implementation

[0017] The improved sand mold assembly for casting, which applies the technical solution of the present invention, will be further described below with reference to the accompanying drawings. Except where explicitly stated to be equivalent or alternative embodiments, the various implementation details disclosed below may be selectively applied or combined in a single embodiment even if they are not directly related or synergistic in function.

[0018] like Figures 1-6As shown, this invention proposes an improved sand mold assembly for casting, comprising an upper sand mold 1 and a lower sand mold 2 made of sand. The upper sand mold 1 includes an upper template 11 and an upper mold core 12 protruding downwards from the bottom surface of the upper template 11. The lower sand mold 2 includes a lower template 21 and a front mold wall 22, a rear mold wall 23, a left mold wall 24, a right mold wall 25, and a bottom mold wall 26 connected to the lower template 21. The mold wall 25 and the mold bottom wall 26 define a lower mold cavity 20 that can accommodate the upper mold core 12. When the upper sand mold 1 and the lower sand mold 2 are combined, a casting cavity for casting component 5 is formed between the upper mold core 12 and the lower mold cavity 20. A feed port 31 and an overflow port 32 are provided on the upper mold plate 11. A gating channel 27 is provided on the side of the lower mold plate 21 near the front mold wall 22. One end of the gating channel 27 is connected to the feed port 31 and the other end is connected to the lower mold core 12. The casting cavity includes an overflow port 32 located near the rear mold wall 23, with at least a portion of the overflow port 32 communicating with the casting cavity. The front mold wall 22, rear mold wall 23, left mold wall 24, and right mold wall 25 have substantially the same wall thickness. A left groove 241 and a right groove 251 are respectively provided on the left mold wall 24 and right mold wall 25, communicating with the casting cavity. The cavity also includes a left chill block 41 and a right chill block 42. Block 41 is disposed in the left groove 241 and the inner side of the left chill block 41 is flush with the wall surface of the left mold wall 24. The right chill block 42 is disposed in the right groove 251 and the inner side of the right chill block 42 is flush with the wall surface of the right mold wall 25. The shape of the mold bottom wall 26 follows the shape of the bottom surface of the casting component 5, and the wall thickness of the mold bottom wall 26 and the upper mold core 12 is greater than the wall thickness of the front mold wall 22, the rear mold wall 23, the left mold wall 24 and the right mold wall 25.

[0019] In this embodiment, the upper sand mold 1 and the lower sand mold 2 are components manufactured by 3D printing. The sand used for their production is a mixture of high-temperature resistant quartz sand and furan resin, and the entire assembly is printed as a single piece. This not only results in fast molding speed but also high structural strength. The thickness of the upper mold 11 and the lower mold 21 is between 28mm and 50mm. Figure 3As shown, to facilitate the pouring of molten metal, the height of the inlet 31 and overflow 32 on the upper mold plate 11 is greater than the thickness of the upper mold plate 11. The wall thickness of the lower mold plate 21, the front mold wall 22, the rear mold wall 23, the left mold wall 24, the right mold wall 25, and the bottom mold wall 26 is greatly reduced. The shapes of the front mold wall 22, the rear mold wall 23, the left mold wall 24, the right mold wall 25, and the bottom mold wall 26 forming the lower mold cavity 20 can be made according to the shape of the casting component 5. This not only reduces the use of manufacturing materials but also facilitates rapid heat dissipation of the casting. The upper mold core 12 is a component that can extend into the lower mold cavity 20. The outer surface of the upper mold core 12, the inner surface of the lower mold cavity 20, and part of the lower surface of the upper mold plate 11 form the casting cavity. In this embodiment, the upper mold core 12 is a solid structure.

[0020] The bottom wall 26 is a wall component located at the bottom of the casting cavity. During the casting process, the weight of the molten metal is mainly supported by the bottom wall 26. In addition, after the molten metal enters from the inlet 31, it mainly flows to the overflow port 32 through the casting cavity between the bottom wall 26 and the upper mold core 12. From the perspective of the flow direction of the molten metal, the bottom channel is not only the longest, but this part of the casting cavity corresponds to the main molding wall of the casting part. Therefore, it is necessary to increase its cooling and feeding time. Therefore, the wall thickness of the bottom mold wall 26 and the upper mold core 12 is set to be greater than the wall thickness of the front mold wall 22, the rear mold wall 23, the left mold wall 24, and the right mold wall 25. This not only enhances the structural strength of the bottom mold wall 26 to support the casting component 5, but also reduces the heat dissipation rate of the bottom mold wall 26 and the upper mold core 12, thus slowing down the condensation rate of the molten metal between them. This is beneficial for the molten metal to flow smoothly from the inlet 31 to the overflow port 32 during pouring, and after pouring, the metal stored in the inlet 31 and the overflow port 32 can also fully compensate for the shrinkage of the wall between the bottom mold wall 26 and the upper mold core 12. This is beneficial for improving the forming quality of the casting component 5. In addition, by providing left grooves 241 and right grooves 251 on the left mold wall 24 and right mold wall 25 respectively, and by providing left chill blocks 41 and right chill blocks 42 in the left grooves 241 and right grooves 251, the left chill blocks 41 and right chill blocks 42 can quickly absorb heat, allowing the molten metal filling the space between the left mold wall 24, right mold wall 25 and upper mold core 12 to cool and solidify rapidly. The molten metal in the feed port 31 and overflow port 32 concentrates to fully compress the wall between the bottom mold wall 26 and upper mold core 12. This not only improves the forming quality of the main molding wall of the casting component 5, but also increases the cooling and forming speed of the high casting component 5, thereby improving the overall processing efficiency.

[0021] To facilitate the installation of the left chill block 41 and the right chill block 42, a left retaining groove 242 is provided on the side wall of the left groove 241, and a right retaining groove 252 is provided on the side wall of the right groove 251. A left retaining arm 411 is provided on the side wall of the left chill block 41, and a right retaining arm 421 is provided on the side wall of the right chill block 42. When the left chill block 41 and the right chill block 42 are placed in the left groove 241 and the right groove 251, the left retaining arm 411 can be engaged in the left retaining groove 242, and the right retaining arm 421 can be engaged in the right retaining groove 252. Through the limitation of the left retaining groove 242 and the right retaining groove 252, the left chill block 41 and the right chill block 42 can be stably connected in the lower sand mold 2.

[0022] Furthermore, the upper surfaces of the left chill block 41 and the right chill block 42 are lower than the upper surface of the lower sand mold 2. The upper sand mold 1 also includes a left pressing boss 13 and a right pressing boss 14 with downward protrusions on the bottom surface of the upper template 11. When the upper sand mold 1 and the lower sand mold 2 are combined, the left pressing boss 13 and the right pressing boss 14 press against the upper surfaces of the left chill block 41 and the right chill block 42, respectively. This allows the lower middle part of the left and right side walls of the casting component 5 to cool first, which helps to accelerate the overall solidification rate of the casting component 5 and also ensures the feeding effect of the bottom wall of the casting component 5.

[0023] Furthermore, the upper ports of the left groove 241 and the right groove 251 are respectively provided with a left guide angle 243 and a right guide angle 253, and the roots of the left pressing boss 13 and the right pressing boss 14 are respectively provided with a left chamfer 131 and a right chamfer 141 that match the left guide angle 243 and the right guide angle 253. This facilitates the automatic guidance and alignment of the left pressing boss 13 and the right pressing boss 14 with the left groove 241 and the right groove 251.

[0024] To create a cooling channel inside the casting component 5, the upper sand mold 1 also includes an inverted V-shaped pipe core 6. The pipe core 6 includes a core body 61 and core connecting feet 62 connected to both ends of the core body 61. The two core connecting feet 62 are connected to the upper template 11, thus supporting the core body 61 suspended in the casting cavity. Both the upper sand mold 1 and the lower sand mold 2 are 3D printed, and the upper template 11, upper core 12, and pipe core 6 are integrally printed. In this embodiment, when the upper sand mold 1 and lower sand mold 2 are combined, the pipe core 6 is positioned between the upper core 12 and the front mold wall 22. In another embodiment, the pipe core 6 is positioned between the upper core 12 and the rear mold wall 23, which reduces the impact of molten metal on the pipe core 6.

[0025] Because the flow of molten metal has a certain impact force, in order to improve the positional stability of the cooling channel, the pipe mold core 6 further includes at least one intermediate support foot 63. The intermediate support foot 63 is arranged between the two mold core connecting feet 62. One end of the intermediate support foot 63 is connected to the middle of the pipe mold core 6, and the other end is connected to the upper template 11. The diameter of the intermediate support foot 63 is larger than the diameter of the mold core connecting feet 62. Because of the intermediate support foot 63, the casting component 5 will inevitably form an auxiliary through hole after molding. In order to prevent refrigerant leakage, a sealing plug is used to seal the auxiliary through hole.

Claims

1. An improved sand mold assembly for casting, comprising an upper sand mold and a lower sand mold made of sand material, the upper sand mold comprising an upper mold plate and an upper mold core arranged in a downward protruding manner on the bottom surface of the upper mold plate, the lower sand mold comprising a lower mold plate and a front mold wall, a rear mold wall, a left mold wall, a right mold wall and a mold bottom wall connected to the lower mold plate, the front mold wall, the rear mold wall, the left mold wall, the right mold wall and the mold bottom wall defining a lower mold cavity capable of accommodating the upper mold core, when the upper sand mold and the lower sand mold are combined, a casting cavity for casting a component is formed between the upper mold core and the lower mold cavity; a feeding port and a sprue port are arranged on the upper mold plate, a pouring channel is arranged on the lower mold plate near the front mold wall, one end of the pouring channel is connected to the feeding port and the other end is connected to the casting cavity, the sprue port is arranged near the rear mold wall and at least part of the sprue port is in communication with the casting cavity; characterized in that, The wall thickness of the front mold wall, the rear mold wall, the left mold wall and the right mold wall is substantially the same, the left recess and the right recess are arranged on the left mold wall and the right mold wall respectively, the left recess and the right recess communicate with the casting cavity, and the left chill block and the right chill block are arranged in the left recess and the right recess respectively, the inner side surface of the left chill block is flush with the wall surface of the left mold wall, the inner side surface of the right chill block is flush with the wall surface of the right mold wall, the shape of the mold bottom wall and the upper mold core is arranged according to the shape of the bottom surface of the casting member, and the wall thickness of the mold bottom wall is greater than the wall thickness of the front mold wall, the rear mold wall, the left mold wall and the right mold wall.

2. The improved sand mold package for casting according to claim 1, wherein, A left clamping groove is arranged on the groove side wall of the left recess, a right clamping groove is arranged on the groove side wall of the right recess, a left clamping arm is arranged on the side wall of the left chill block, a right clamping arm is arranged on the side wall of the right chill block, when the left chill block and the right chill block are placed into the left recess and the right recess, the left clamping arm can be clamped into the left clamping groove, and the right clamping arm can be clamped into the right clamping groove.

3. The improved sand mold package for casting according to claim 2, wherein, The upper surfaces of the left chill block and the right chill block are lower than the upper surface of the upper sand mold, the upper sand mold further comprises left and right pressing bosses arranged downwardly on the bottom surface of the upper mold plate, and when the upper sand mold and the lower sand mold are combined, the left and right pressing bosses press against the upper surfaces of the left and right chill blocks respectively.

4. The improved sand mold package for casting according to claim 3, wherein, The upper ends of the left recess and the right recess are respectively provided with left and right guide angles, and the roots of the left and right pressing bosses are respectively provided with left and right chamfers matched with the left and right guide angles.

5. The improved sand mold package for casting according to any one of claims 1 to 4, wherein The upper sand mold further comprises a pipeline mold core in the shape of an inverted U, the pipeline mold core comprises a pipeline core body and mold core connecting feet connected to both ends of the pipeline core body, and the two mold core connecting feet are connected to the upper mold plate, so that the pipeline core body is suspended in the casting cavity.

6. The improved sand mold package for casting according to claim 5, wherein, The upper sand mold and the lower sand mold are both formed by three-dimensional printing, and the upper sand mold, the upper mold core and the pipeline mold core are integrally printed and formed.

7. The improved sand mold package for casting according to claim 5, wherein, The pipeline mold core further comprises at least one intermediate supporting foot, one end of the intermediate supporting foot is connected to the middle part of the pipeline mold core, and the other end of the intermediate supporting foot is connected to the upper mold plate.

8. The improved sand mold package for casting according to claim 7, wherein, The diameter of the intermediate supporting foot is greater than the diameter of the mold core connecting feet.

9. The improved sand mold package for casting according to claim 5, wherein, When the upper sand mold and the lower sand mold are combined, the pipeline mold core is arranged between the upper mold core and the rear mold wall.

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