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] The invention relates to the technical field of sand molds, and in particular to an improved sand mold combination for casting. Background Art

[0002] In the low-pressure die-casting technology of wheel hubs, the manufacturing accuracy and quality of the casting mold play an important role in affecting the quality of the wheel hub products. Some of the casting mold components are processed by sand casting, such as side mold cast steel parts, etc. Therefore, the manufacturing quality of the sand mold plays a vital role in the quality of the casting mold components. Among them, in order to improve the casting quality of the wheel hub side mold, the applicant has previously proposed a sand mold combination for casting the wheel hub side mold, and its publication number is CN115958159A. The sand mold combination 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, the right longitudinal cavity wall, the front transverse cavity wall, the rear transverse cavity wall and the cavity bottom wall form a concave cavity with an opening facing upward; when the upper sand mold and the lower sand mold are closed together, the core is inserted into the concave cavity, and a core is set on the left longitudinal cavity wall. There is a first lower riser cavity with an upward opening, and the first lower riser cavity is used to supply casting molten liquid to the casting cavity; a liquid inlet channel is arranged on the wall body on the left side of the core on the upper sand mold, and a pair of second upper riser channels arranged front and back are arranged on the wall body on the right side of the core on the upper sand mold, and the pair of second upper riser channels respectively penetrate the bottom wall of the upper sand mold downward; the advantage of such a setting is that the first lower riser cavity and the second upper riser channel are used to timely supply casting molten liquid to the casting part close to the left longitudinal cavity wall and the right longitudinal cavity wall that solidify later, so as to reduce the defects such as shrinkage cavities and shrinkage in the cast wheel hub side mold casting. After actual verification, although this technology improves the casting quality of the wheel hub side mold casting to a certain extent, there is still room for improvement in processing speed and manufacturing accuracy. Summary of the invention

[0003] In order to further improve the deficiencies in the prior art, the present invention proposes an improved sand mold combination for casting, comprising an upper sand mold and a lower sand mold made of sand material, the upper sand mold comprising an upper template and an upper mold core arranged on the bottom surface of the upper template and convexly arranged downward, the lower sand mold comprising a lower template 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 template, the front mold wall, the rear mold wall, the left mold wall, the right mold wall and the mold bottom wall define a lower mold cavity that can accommodate the upper mold core, and when the upper sand mold is combined with the lower sand mold, a casting cavity for casting components is formed between the upper mold core and the lower mold cavity; a feed port and an overflow port are arranged on the upper template, and a pouring runner is arranged on the side close to the front mold wall, and one end of the pouring runner is connected to the feed port and the other end is connected to the feed port. One end is connected to the casting cavity, the overflow port is arranged close to the rear mold wall and at least part of the overflow port is connected to the casting cavity; it is characterized in that the wall thicknesses of the front mold wall, the rear mold wall, the left mold wall and the right mold wall are basically the same, and 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 include a left cold iron block and a right cold iron block, the left cold iron block is arranged in the left groove and the inner side surface of the left cold iron block is flush with the wall surface of the left mold wall, the right cold iron block is arranged in the right groove and the inner side surface of the right cold iron 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, the rear mold wall, the left mold wall and the right mold wall.

[0004] Among them, the upper sand mold is a component formed by three-dimensional printing. The upper mold plate of the upper mold core and the upper mold core are integrally formed with the pipe mold core mentioned below. The sand material used for its production is a mixture of high-temperature resistant quartz sand and furan resin. It not only has a fast molding speed but also has high structural strength. Due to the use of a three-dimensional printing process with high structural strength, the material thickness of the upper mold plate can be between 28mm and 50mm, so the material used for the sand mold can be greatly reduced. Furthermore, in order to facilitate the pouring of molten metal, the height of the feed port and the overflow port arranged on the upper mold plate is higher than the thickness of the upper mold plate.

[0005] Among them, the lower sand mold is also a component made by three-dimensional printing. The wall thickness of the lower mold plate and the front mold wall, rear mold wall, left mold wall, right mold wall, and mold bottom wall are greatly reduced. The shapes of the front mold wall, rear mold wall, left mold wall, right mold wall, and mold bottom wall forming the lower mold cavity can be made according to the shape of the casting component, which 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, and 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 plate form the casting cavity. There are two implementation methods of the upper mold core, one is a wall structure that changes with the shape of the lower surface, and the other is a solid structure.

[0007] Among them, the wall thicknesses of the front mold wall, rear mold wall, left mold wall and right mold wall are basically the same, which is the wall thickness when the left cold iron block and the right cold iron block are excluded. Due to the influence of manufacturing deviations, there will be certain manufacturing errors in the wall thickness of each wall body, which has basically no effect on the manufacturing and heat dissipation effects of the cast parts.

[0008] Among them, the mold bottom wall is a wall component arranged 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 to the overflow port through the casting cavity between the mold bottom wall and the upper mold core. This section of the flow channel is longer than the flow channels on both sides, and this section of the flow channel corresponds to the main appearance surface or functional surface of the casting component. Shrinkage compensation for it is beneficial to improve the molding quality of the component.

[0009] According to the above technical scheme, compared with the prior art, the beneficial technical effects of the present invention are: first, the wall thickness of the mold bottom wall and the upper mold core is set to be greater than the wall thickness of the front mold wall, the rear mold wall, the left mold wall and the right mold wall, which not only enhances the structural strength of the mold bottom wall to support the casting component, but also reduces the heat dissipation rate of the mold bottom wall and the upper mold core to slow down the condensation rate of the molten metal therebetween, which is beneficial for the molten metal to flow smoothly from the feed port to the overflow port during pouring, and after the pouring is completed, the molten metal stored in the feed port and the overflow port can also fully compensate for the wall between the mold bottom wall and the upper mold core, which is beneficial The invention is to improve the molding quality of the casting component; secondly, by respectively arranging the left groove and the right groove on the left mold wall and the right mold wall, and arranging the left cold iron block and the right cold iron block in the left groove and the right groove, the left cold iron block and the right cold iron block can quickly absorb heat, so that the molten metal filled between the left mold wall, the right mold wall and the upper mold core can be quickly cooled and solidified, and the molten metal stored in the feed port and the overflow port is concentrated on the wall body between the mold bottom wall and the upper mold core to fully compensate for the shrinkage, which not only improves the molding quality of the main molding wall body of the casting component, but also improves the cooling molding speed of the high casting component and improves the overall processing efficiency.

[0010] Since the present invention has the above characteristics and advantages, it can be applied to an improved sand mold combination for casting. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the axial direction structure of an improved sand mold assembly for casting; Figure 2 It is a schematic diagram of the structure of the improved sand mold assembly for casting in a top view; Figure 3 yes Figure 2 Schematic diagram of the cross-section structure in the AA direction; Figure 4 It is a schematic diagram of the explosion structure of the improved sand mold assembly for casting; Figure 5 is a schematic diagram of the structure of the upper sand mold in the axial direction; Figure 6 It is a schematic diagram of the axial structure of the lower sand mold. DETAILED DESCRIPTION

[0012] The structure of the improved casting sand mold assembly using the technical solution of the present invention is further described below in conjunction with the accompanying drawings. Except for the embodiments that are explicitly described as equivalent or optional, the various implementation details disclosed below can be selectively applied or combined in one embodiment even if they are not directly related or coordinated in terms of function.

[0013] like Figure 1 to Figure 6As shown in the figure, an improved casting sand mold assembly proposed by the present invention comprises an upper sand mold 1 and a lower sand mold 2 made of sand material, wherein the upper sand mold 1 comprises an upper mold plate 11 and an upper mold core 12 arranged on the bottom surface of the upper mold plate 11 and convexly arranged downward, and the lower sand mold 2 comprises a lower mold plate 21 and a front mold wall 22, a rear mold wall 23, a left mold wall 24, a right mold wall 25, and a mold bottom wall 26 connected to the lower mold plate 21, wherein the front mold wall 22, the rear mold wall 23, the left mold wall 24, the right mold wall 25, and the mold bottom wall 26 are connected to the lower mold plate 21. The mold wall 25 and the mold bottom wall 26 define a lower mold cavity 20 capable of accommodating the upper mold core 12. When the upper sand mold 1 is combined with the lower sand mold 2, a casting cavity for casting the 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 pouring channel 27 is provided on the side close to the front mold wall 22 of the lower mold plate 21. One end of the pouring channel 27 is connected to the feed port 31 and the other end is connected to the The casting cavity, the overflow port 32 is arranged near the rear mold wall 23 and at least part of the overflow port 32 is connected to the casting cavity; the wall thicknesses of the front mold wall 22, the rear mold wall 23, the left mold wall 24 and the right mold wall 25 are substantially the same, and a left groove 241 and a right groove 251 are respectively provided on the left mold wall 24 and the right mold wall 25, and the left groove 241 and the right groove 251 are connected to the casting cavity, and also include a left cold iron block 41 and a right cold iron block 42, the left cold iron block The block 41 is arranged in the left groove 241 and the inner side surface of the left cold iron block 41 is flush with the wall surface of the left mold wall 24, the right cold iron block 42 is arranged in the right groove 251 and the inner side surface of the right cold iron block 42 is flush with the wall surface of the right mold wall 25, the shape of the mold bottom wall 26 is arranged according to the bottom surface shape 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.

[0014] In this embodiment, the upper sand mold 1 and the lower sand mold 2 are components formed by three-dimensional printing. The sand material used for making them is a mixture of high-temperature resistant quartz sand and furan resin. The whole is printed and formed in one piece, which not only has a fast forming speed but also has high structural strength. Among them, the material thickness of the upper template 11 and the lower template 21 is between 28mm and 50mm. Figure 3As shown, in order to facilitate the pouring of molten metal, the height of the feed port 31 and the overflow port 32 arranged on the upper mold plate 11 is higher than the thickness of the upper mold plate 11. The wall thickness of the lower mold plate 21 and the front mold wall 22, the rear mold wall 23, the left mold wall 24, the right mold wall 25, and the mold bottom wall 26 are greatly reduced, wherein 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 mold bottom wall 26 forming the lower mold cavity 20 can be made according to the shape of the casting component 5, which can not only reduce the use of manufacturing materials, but also facilitate the rapid heat dissipation of the casting. The upper mold core 12 is a component that can be extended into the lower mold cavity 20, and 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.

[0015] Among them, the mold bottom wall 26 is a wall component arranged 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 26. In addition, after the molten metal enters from the feed port 31, it mainly flows to the overflow port 32 through the casting cavity between the mold bottom wall 26 and the upper mold core 12. From the flow direction of the molten metal, the flow channel length at the bottom is not only the longest, but also this part of the casting cavity corresponds to the main molding wall of the cast part, so it is necessary to increase its cooling and shrinkage compensation time. To this end, the wall thickness of the mold bottom 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 mold bottom wall 26 to support the casting component 5, but also reduces the heat dissipation rate of the mold bottom wall 26 and the upper mold core 12 to slow down the condensation rate of the molten metal therebetween, which is beneficial for the molten metal to flow smoothly from the feed port 31 to the overflow port 32 during pouring, and after the pouring is completed, the metal stored in the feed port 31 and the overflow port 32 can also fully compensate for the wall between the mold bottom wall 26 and the upper mold core 12, which is beneficial to improving the molding quality of the casting component 5. In addition, by respectively arranging a left groove 241 and a right groove 251 on the left mold wall 24 and the right mold wall 25, and arranging a left cold iron block 41 and a right cold iron block 42 in the left groove 241 and the right groove 251, the left cold iron block 41 and the right cold iron block 42 can quickly absorb heat, so that the molten metal filled between the left mold wall 24, the right mold wall 25 and the upper mold core 12 can be quickly cooled and solidified, and the molten metal stored in the feed port 31 and the overflow port 32 is concentrated on the wall body between the mold bottom wall 26 and the upper mold core 12 to fully compensate for the shrinkage, which not only improves the molding quality of the main molding wall body of the casting component 5, but also simultaneously improves the cooling molding speed of the high casting component 5, thereby improving the overall processing efficiency.

[0016] In order to facilitate the installation of the left cold iron block 41 and the right cold iron block 42, a left clamping groove 242 is provided on the groove side wall of the left groove 241, a right clamping groove 252 is provided on the groove side wall of the right groove 251, a left clamping arm 411 is provided on the side wall of the left cold iron block 41, and a right clamping arm 421 is provided on the side wall of the right cold iron block 42. When the left cold iron block 41 and the right cold iron block 42 are placed in the left groove 241 and the right groove 251, the left clamping arm 411 can be clamped into the left clamping groove 242, and the right clamping arm 421 can be clamped into the right clamping groove 252. Through the definition of the left clamping groove 242 and the right clamping groove 252, the left cold iron block 41 and the right cold iron block 42 can be stably connected to the lower sand mold 2.

[0017] Furthermore, the upper surfaces of the left cold iron block 41 and the right cold iron block 42 are lower than the upper surface of the lower sand mold 2, and the upper sand mold 1 further comprises a left pressing boss 13 and a right pressing boss 14 which are arranged on the bottom surface of the upper mold plate 11 and are convex downwardly arranged. When the upper sand mold 1 is combined with the lower sand mold 2, the left pressing boss 13 and the right pressing boss 14 are pressed against the upper surfaces of the left cold iron block 41 and the right cold iron block 42 respectively. In this way, the middle and lower parts of the left and right walls of the casting component 5 can be cooled first, which is conducive to accelerating the condensation speed of the casting component 5 as a whole, and also ensures the shrinkage compensation effect of the bottom wall of the casting component 5.

[0018] Furthermore, the upper ends 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 press-fitting boss 13 and the right press-fitting 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 is conducive to allowing the left press-fitting boss 13 and the right press-fitting boss 14 to automatically guide and align with the left groove 241 and the right groove 251.

[0019] In order to form a cooling channel inside the casting component 5, the upper sand mold 1 also includes a pipe mold core 6 in the shape of an inverted "X", and the pipe mold core 6 includes a pipe core body 61 and a mold core connecting pin 62 connected to the two ends of the pipe core body 61, and the two mold core connecting pins 62 are connected to the upper mold plate 11, so as to support the pipe core body 61 to be suspended in the casting cavity. The upper sand mold 1 and the lower sand mold 2 are both formed by three-dimensional printing, and the upper mold plate 11, the upper mold core 12 and the pipe mold core 6 are printed and formed as a whole. In this embodiment, when the upper sand mold 1 is combined with the lower sand mold 2, the pipe mold core 6 is arranged between the upper mold core 12 and the front mold wall 22. In another embodiment, the pipe mold core 6 is arranged between the upper mold core 12 and the rear mold wall 23, so that the impact of the molten metal on the pipe mold core 6 can be reduced.

[0020] Since the flow of metal liquid has a certain impact force, in order to improve the position stability of the cooling channel, the pipeline mold core 6 further includes at least one intermediate support foot 63, which 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 pipeline mold core 6, and the other end is connected to the upper mold plate 11. The diameter of the intermediate support foot 63 is larger than the diameter of the mold core connecting foot 62. Because the intermediate support foot 63 is provided, the casting component 5 will inevitably form an auxiliary through hole after molding. In order to prevent the leakage of the refrigerant, the auxiliary through hole is blocked by providing a sealing plug.

Claims

1. An improved casting sand mold combination, 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 on the bottom surface of the upper mold plate and protruding downward, 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 define a lower mold cavity capable of accommodating the upper mold core, when the upper sand mold is combined with the lower sand mold, a casting cavity for casting components is formed between the upper mold core and the lower mold cavity; a feed port and an overflow port are arranged on the upper mold plate, and 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 to the feed port and the other end is connected to the casting cavity, the overflow port is arranged close to the rear mold wall and at least part of the overflow port is connected to the casting cavity; characterized in that The wall thicknesses of the front mold wall, the rear mold wall, the left mold wall and the right mold wall are basically the same. A left groove and a right groove are respectively provided on the left mold wall and the right mold wall, and the left groove and the right groove are connected to the casting cavity. The left mold block and the right mold block are also included. The left mold block is arranged in the left groove and the inner side surface of the left mold block is flush with the wall surface of the left mold wall. The right mold block is arranged in the right groove and the inner side surface of the right mold block is flush with the wall surface of the right mold wall. The shapes of the mold bottom wall and the upper mold core are arranged according to the shape of the bottom surface of the casting component, 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 casting sand mold assembly according to claim 1, characterized in that: A left clamping groove is provided on the side wall of the left groove, a right clamping groove is provided on the side wall of the right groove, a left clamping arm is provided on the side wall of the left cold iron block, and a right clamping arm is provided on the side wall of the right cold iron block. When the left cold iron block and the right cold iron block are placed in the left groove and the right groove, 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 casting sand mold assembly according to claim 2, characterized in that: The upper surfaces of the left cold iron block and the right cold iron block are lower than the upper surface of the lower sand mold. The upper sand mold also includes a left pressing boss and a right pressing boss which are arranged on the bottom surface of the upper mold plate and are protruding downward. When the upper sand mold is combined with the lower sand mold, the left pressing boss and the right pressing boss are pressed against the upper surfaces of the left cold iron block and the right cold iron block respectively.

4. The improved casting sand mold assembly according to claim 3, characterized in that: The upper ports of the left groove and the right groove are respectively provided with a left guide angle and a right guide angle, and the roots of the left press-fit boss and the right press-fit boss are respectively provided with a left chamfer and a right chamfer matching the left guide angle and the right guide angle.

5. The improved casting sand mold assembly according to any one of claims 1 to 5, characterized in that: The upper sand mold also includes a pipe mold core in the shape of an inverted "X", which includes a pipe core body and core connecting feet connected to both ends of the pipe core body, and the two core connecting feet are connected to the upper mold plate, thereby supporting the pipe core body to be suspended in the casting cavity.

6. The improved casting sand mold assembly according to claim 5, characterized in that: 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 printed and formed in one piece.

7. The improved casting sand mold assembly according to claim 5, characterized in that: The pipe mold core also includes at least one middle supporting foot, which is arranged between the two mold core connecting feet, one end of the middle supporting foot is connected to the middle part of the pipe mold core, and the other end is connected to the upper mold plate.

8. The improved casting sand mold assembly according to claim 7, characterized in that: The diameter of the middle supporting leg is greater than the diameter of the core connecting leg.

9. The improved casting sand mold assembly according to claim 5, characterized in that: When the upper sand mold is combined with the lower sand mold, the pipe mold core is arranged between the upper mold core and the rear mold wall.

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