Large sand box with negative pressure

Abstract

A large sand box with negative pressure includes a lower sand box and an upper sand box. The lower and upper sand boxes each contain a lower sand mold and an upper sand mold, respectively. The lower and upper sand molds meet at their midpoints to form a workpiece cavity. The edges of the lower and upper sand molds form a negative pressure cavity. An outward-facing flange is formed at the lower part of the workpiece cavity. A through-hole is machined at the end of the outward-facing flange, connecting to the negative pressure cavity. A connecting pipe is provided on one side of the lower sand box, connecting to the negative pressure cavity, and the other end of the connecting pipe is connected to a vacuum generator. This sand box structure, by setting a negative pressure cavity around the workpiece cavity, and the thin-walled outward-facing flange at the lower part of the workpiece cavity communicating with the negative pressure cavity through a through-hole, allows the vacuum generator to control the pressure within the negative pressure cavity during casting. The negative pressure cavity, through the through-hole, exerts an adsorption effect on the outward-facing flange of the workpiece cavity, ensuring that molten iron flows evenly to the edge of the outward-facing flange and guaranteeing the quality of the casting.

Description

Technical Field

[0001] This utility model relates to a large sand box with negative pressure. Background Technology

[0002] Casting is a process in which metal is melted into a liquid that meets certain requirements, poured into a mold, cooled and solidified, and then cleaned to obtain a casting with a predetermined shape, size, and properties. Because the cast blank is nearly formed, it achieves the purpose of eliminating or minimizing machining, reducing costs and, to some extent, shortening production time. Casting is one of the fundamental processes in modern equipment manufacturing industry.

[0003] Castings come in various shapes. When a casting has a thin-walled flange structure, insufficient pressure at the thin-walled area can lead to incomplete flow of molten iron, resulting in missing edge structures and scrapping of the casting. Current technology often involves thickening the thin-walled structure during forming and then thinning it further, which increases the number of processing steps and affects processing efficiency. Utility Model Content

[0004] To address the shortcomings mentioned above, this utility model provides a large sandbox with negative pressure.

[0005] To achieve the above objectives, this utility model provides a large sand box with negative pressure, including a lower sand box and an upper sand box. The lower sand box and the upper sand box are respectively provided with a lower sand mold and an upper sand mold. The lower sand mold and the upper sand mold are connected at the middle to form a workpiece cavity. The lower sand mold and the upper sand mold are connected at the edges to form a negative pressure cavity. An outward flange is formed at the lower part of the workpiece cavity. A through hole is machined at the end of the outward flange to connect to the negative pressure cavity. A connecting pipe is provided on one side of the lower sand box to connect to the negative pressure cavity. The other end of the connecting pipe is connected to a vacuum generator.

[0006] As a further improvement of this utility model, the through holes are evenly distributed along the outer periphery of the outward flange.

[0007] As a further improvement of this utility model, the left side of the upper sand mold is provided with a sprue that connects to the lower part of the workpiece cavity, and the right side of the upper sand mold is provided with an exhaust port that connects to the upper part of the workpiece cavity.

[0008] The beneficial effects of this utility model are as follows:

[0009] This sand box structure sets a negative pressure chamber around the workpiece cavity. The thin-walled outer edge of the lower part of the workpiece cavity is connected to the negative pressure chamber through a through hole. During the casting process, a vacuum generator is used to control the pressure inside the negative pressure chamber. The negative pressure chamber generates an adsorption force on the outer edge of the workpiece cavity through the through hole, so that the molten iron can flow evenly to the edge of the outer edge, ensuring the quality of the casting in a single molding. Attached Figure Description

[0010] Figure 1 This is a front view of a large sandbox with negative pressure according to the present invention.

[0011] Figure 2 This is a top view of the lower sand box;

[0012] Figure 3 for Figure 1 Enlarged view of point A in the middle.

[0013] In the diagram: 1. Lower sand box; 2. Lower sand mold; 3. Workpiece cavity; 31. Outer flange; 4. Negative pressure chamber; 5. Connecting pipe; 6. Vacuum generator; 7. Upper sand box; 8. Upper sand mold; 9. Sprue; 10. Exhaust port; 11. Through hole. Detailed Implementation

[0014] like Figure 1-3 As shown, the present invention discloses a large sand box with negative pressure, comprising a lower sand box and an upper sand box. The lower sand box and the upper sand box are respectively provided with a lower sand mold and an upper sand mold. The lower sand mold and the upper sand mold are connected at the middle to form a workpiece cavity. The lower sand mold and the upper sand mold are connected at the edges to form a negative pressure cavity. An outward flange is formed at the lower part of the workpiece cavity. Through holes are machined at the end of the outward flange to connect to the negative pressure cavity. The through holes are evenly distributed along the outer periphery of the outward flange. A connecting pipe is provided on one side of the lower sand box to connect to the negative pressure cavity. The other end of the connecting pipe is connected to a vacuum generator. A sprue is provided on the left side of the upper sand mold to connect to the lower part of the workpiece cavity. An exhaust port is provided on the right side of the upper sand mold to connect to the upper part of the workpiece cavity.

[0015] This sand box structure sets a negative pressure chamber around the workpiece cavity. The thin-walled outer edge of the lower part of the workpiece cavity is connected to the negative pressure chamber through a through hole. During the casting process, a vacuum generator is used to control the pressure inside the negative pressure chamber. The negative pressure chamber generates an adsorption force on the outer edge of the workpiece cavity through the through hole, so that the molten iron can flow evenly to the edge of the outer edge, ensuring the quality of the casting in a single molding.

[0016] In practical use, for ease of understanding of this utility model, it will be described in conjunction with the accompanying drawings;

[0017] The solution in this embodiment is mainly used for casting castings with thin-walled flange structures;

[0018] During operation, after the upper and lower sand molds are closed, molten iron flows into the workpiece cavity along the gating system. Simultaneously, a vacuum generator evacuates the negative pressure chamber through a connecting pipe, reducing the air pressure within. Due to the small thickness of the outer flange, the molten iron experiences significant flow resistance at this location. The molten iron cannot quickly and evenly cover the corners of the outer flange by its own weight, necessitating an increase in the outer flange thickness during design, resulting in material waste and increased processing time. Now, by using a through-hole in the negative pressure chamber to create an adsorption force at the lower part of the workpiece cavity near the outer flange, the molten iron can flow evenly to the edge of the outer flange. This adsorption force can be adjusted by controlling the pressure within the negative pressure chamber. After casting, only very small burrs will form at the outer flange location, which are easy to remove later.

[0019] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A large sand box with negative pressure, comprising a lower sand box (1) and an upper sand box (7), wherein a lower sand mold (2) and an upper sand mold (8) are respectively provided in the lower sand box (1) and the upper sand box (7), and the lower sand mold (2) and the upper sand mold (8) are joined at the middle to form a workpiece cavity (3), characterized in that: The lower sand mold (2) and the upper sand mold (8) form a negative pressure cavity (4) at their edges. The lower part of the workpiece cavity (3) has an outward flange (31). The end of the outward flange (31) is machined with a through hole (11) to connect to the negative pressure cavity (4). A connecting pipe (5) is provided on one side of the lower sand box (1) to connect to the negative pressure cavity (4). The other end of the connecting pipe (5) is connected to a vacuum generator (6).

2. A large sandbox with negative pressure according to claim 1, characterized in that: The through holes (11) are evenly distributed along the outer periphery of the outer flange (31).

3. A large sandbox with negative pressure according to claim 1, characterized in that: The upper sand mold (8) has a sprue (9) on the left side that connects to the lower part of the workpiece cavity (3), and an exhaust port (10) on the right side that connects to the upper part of the workpiece cavity (3).

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