Aluminum alloy casting die-casting structure

Abstract

The utility model relates to the technical field of die-casting dies, in particular to an aluminum alloy casting die-casting structure, which is characterized in that a groove is arranged on a forming surface of a die core of a fixed die at a position corresponding to a screw hole, and a boss is formed on an aluminum alloy die-casting in a cavity corresponding to the groove. One end of the extrusion pin is fixedly connected with the fixed die core through the extrusion oil cylinder, and the other end of the extrusion pin penetrates through the fixed die core to be located in the boss, so that boss waste can be extruded under the action of the extrusion oil cylinder after a die casting is formed, and the compactness of a casting material on the side face of the extrusion pin is improved; and the phenomena of internal structure looseness of the die casting and internal looseness of the casting and residual of under-casting air holes can be reduced, so that the quality of screw holes around the boss can be ensured, the internal quality of the die casting is greatly improved, the control quality of a machining process is improved, the manufacturing cost is reduced, and the production efficiency is greatly improved. And meanwhile, the subsequent machining quality of the die casting is guaranteed, and the product quality is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of die casting molds, in particular to a die casting structure of an aluminum alloy casting. Background Art

[0002] In recent years, the die-casting process for aluminum alloy die-casting has seen new advancements, such as the transition from multi-step cold stamping to continuous cold stamping production, where individual parts are robotically welded together to form body and chassis components. Cold stamping is a common practice on the market, but in recent years, with the continued development of new energy vehicles, it has been gradually replaced by integrated die-casting. For example, the overall weight of new energy vehicles is constantly decreasing. As a future trend in lightweighting vehicles, aluminum and magnesium alloy die-casting offers advantages over cold stamping sheet metal, such as the ability to produce products with larger surface areas.

[0003] Die castings can be combined with many small stamping parts to complete an integrated die casting process, saving the traditional cold stamping welding station and improving production efficiency. Specifically, the molten aluminum is injected into the cavity through the material cylinder, and the molten aluminum is injected into the cavity when the movable and fixed molds are closed to realize the molding process. Existing die castings have a disadvantage. After the die casting is completed by high-pressure casting, when the product needs to be machined to remove excess burrs and waste after die casting, the screw holes on the die castings are often easy to stick to the inside of the product holes, resulting in air holes or under-casting during machining, resulting in lack of material when machining the screw holes on the product, causing product scrapping or customer complaints after delivery. Utility Model Content

[0004] In view of the above-mentioned problems of internal pores and undercasting in die castings, the utility model provides an aluminum alloy casting die casting structure to overcome the problems of pores and undercasting in original die castings.

[0005] The utility model solves the above technical problems through the following technical solutions:

[0006] A die-casting structure for an aluminum alloy casting, comprising a movable die core, a fixed die core, an extrusion pin and an extrusion cylinder;

[0007] The fixed mold core and the movable mold core are in contact with each other and form a cavity, an aluminum alloy die-casting is formed in the cavity, and screw holes are formed on the aluminum alloy die-casting, a groove is provided on the molding surface of the fixed mold core at a position corresponding to the screw hole, and a boss is provided on the aluminum alloy die-casting corresponding to the groove;

[0008] One end of the extrusion pin is fixedly connected to the fixed mold core through the extrusion cylinder, and the other end passes through the fixed mold core and is located in the boss.

[0009] In some embodiments, the end of the extrusion pin extending into the boss is a pointed tip or a rounded tip.

[0010] In some embodiments, the angle of the pointed or rounded head is 45°.

[0011] In some embodiments, the extrusion pin is made of hot working die steel.

[0012] In some embodiments, the surface of the hot working die steel is covered with a composite nitrided layer.

[0013] In some embodiments, the extrusion pin is detachably fixed to the extrusion cylinder.

[0014] In some embodiments, the boss is arranged perpendicular to the screw hole.

[0015] The above utility model has at least one of the following advantages or beneficial effects:

[0016] The utility model discloses a die-casting structure for aluminum alloy castings, wherein grooves are provided on the forming surface of the fixed die core at positions corresponding to the screw holes, and a boss is formed on the aluminum alloy die-casting located in the mold cavity corresponding to the groove, and one end of an extrusion pin is fixedly connected to the fixed die core through an extrusion oil cylinder, and the other end passes through the fixed die core and is located in the boss, so that after the die-casting is formed, the boss waste can be extruded under the action of the extrusion oil cylinder, thereby improving the density of the casting material on the side of the extrusion pin, reducing the occurrence of loose tissue inside the die-casting and residual loose under-cast pores inside the casting, thereby ensuring the quality of the screw holes around the boss, and thus greatly improving the internal quality of the die-casting, improving the control quality of the machining process, reducing the manufacturing cost, and greatly improving the production efficiency. At the same time, the quality of subsequent machining of the die-casting is guaranteed, the product quality is improved, and casting defects can be effectively prevented, the qualified rate of the product is improved, and the existing structure is greatly optimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention and its features, configurations, and advantages will become more apparent upon reading the detailed description of the non-limiting embodiments described below with reference to the accompanying drawings. Like reference numerals indicate like parts throughout the drawings. The drawings are not necessarily drawn to scale, with emphasis placed on illustrating the subject matter of the present invention.

[0018] Figure 1 This is a structural diagram of the die-casting structure of an aluminum alloy casting in an embodiment of the present utility model;

[0019] In the figure, 1 is the forming surface of the fixed mold core; 2 is the aluminum alloy casting; 21 is the screw hole; 22 is the boss; 3 is the extrusion pin; and 4 is the extrusion cylinder. DETAILED DESCRIPTION

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0021] It should be noted that the aluminum alloy die-casting with bosses in this embodiment is cast into various product shapes by injecting aluminum hydraulically into the mold cavity through a die-casting machine through a material cylinder. In this embodiment, grooves (i.e., concave molding grooves) are provided on the molding surface of the fixed mold core at positions corresponding to the screw holes, and the corresponding positions in the mold cavity are boss shapes. Specifically, aluminum hydraulic injection is injected through the material cylinder into the mold cavity of the movable fixed mold. The aluminum liquid is filled into the mold to complete the aluminum alloy die-casting with bosses in the mold. The extrusion pin is driven forward by the extrusion cylinder. The 45-degree pointed head or arc head inclined surface is driven by the cylinder to extrude the reserved boss of the die-casting. Under the action of mechanical injection external force, the aluminum liquid is sent into the mold cavity, so that the aluminum alloy casting can obtain a bulge corresponding to the groove on the molding surface of the fixed mold core, which is beneficial to the subsequent machining of the die casting to remove excess waste and prevent the internal structure of the casting from containing undercasting or air holes remaining in the product. The 45-degree pointed bevel is used to extrude the boss when the die casting is completed, which greatly improves the quality of the product. In addition, its operation is relatively simple, which improves production efficiency and reduces the scrap rate of the product.

[0022] like Figure 1 As shown, the utility model discloses an aluminum alloy casting die-casting structure, specifically, the aluminum alloy casting die-casting structure includes a movable mold core, a fixed mold core, an extrusion pin 3 and an extrusion cylinder 4; the fixed mold core and the movable mold core contact each other and form a cavity, an aluminum alloy die-casting 2 is formed in the cavity, and a screw hole 21 is formed on the aluminum alloy casting 2, a groove is provided on the molding surface 1 of the fixed mold core at a position corresponding to the screw hole 21, and a boss 22 is provided on the aluminum alloy casting corresponding to the groove (the boss 22 is shaped like a fleshy part protruding from the surface of the aluminum alloy casting 2, so it can also be called Fleshy boss); one end of the extrusion pin 3 is fixedly connected to the fixed mold core through the extrusion cylinder 4 (the extrusion cylinder 4 is the cylinder 4 inside the fixed mold), and the other end passes through the fixed mold core and is located in the boss 22; the extrusion pin 3 is installed on the fixed mold through the movement of the extrusion cylinder 4, and when the aluminum liquid is injected into the mold cavity when the dynamic and fixed molds are closed, the extrusion pin 3 can complete the extrusion of the boss 22 waste under the push of the extrusion cylinder 4, and an extrusion inner hole is formed on the boss 22 after extrusion, that is, the extrusion inner hole is formed by the extrusion pin 3 extruding the boss 22 on the aluminum alloy casting 2 under the action of the extrusion cylinder 4.

[0023] Specifically, the use of the aluminum alloy casting 2 with the boss 22 can improve the internal structure density of the casting, thereby improving the material density of the side of the extrusion pin 3, and machining the screw holes 21 around the boss 22 can also ensure quality.

[0024] In a specific embodiment of the present invention, the above-mentioned extrusion pin 3 is made of hot working die steel (i.e., SKD61), and the hot working die steel is subjected to a composite nitriding heat treatment to form a composite nitriding layer. Since the composite nitriding treatment has the characteristics of good wear resistance, high processing precision, high temperature resistance, and not easy to be bitten during the extrusion process, the extrusion cylinder 4 carries the extrusion pin 3 to run with higher precision and more stability without offset.

[0025] In a specific embodiment of the present invention, the extrusion pin 3 can be detachably fixed to the extrusion cylinder 4 to facilitate replacement. Specifically, the extrusion pin 3 can be detachably fixed to the extrusion cylinder 4 through a cylinder connecting assembly.

[0026] In a specific embodiment of the present invention, one end of the extrusion pin 3 extending into the boss 22 is a pointed head or an arc head (only the pointed head is shown in the figure), and the angle of the pointed head or the arc head is 45° (the pointed head surface or the arc head protrudes from the bottom end of the extrusion pin body and forms a 45-degree inclined surface. The 45-degree shape can be extruded in both directions through an angle to perform extrusion movement on both sides of the internal structure of the die-casting along the 45-angle surface).

[0027] In a specific embodiment of the present invention, the boss 22 is arranged perpendicular to the screw hole 21 .

[0028] Specifically, the process of forming the aluminum alloy casting 2 with the boss 22 (the die-casting movable mold and the fixed mold are combined to complete the part molding process in one shot) is as follows:

[0029] During aluminum hydraulic casting, the die-casting machine drives the movable die and the fixed die to gradually approach the mold. Under the vacuum state in the mold, the aluminum liquid is injected into the runner plate through the injection punch and enters the plum blossom core. Driven by the plum blossom and the diverter cone, the aluminum liquid flows downward through the runner. After the movable die and the fixed die of the die-casting mold are closed, all the product shapes in the vacuum mold are completed by diversion. The die-casting molding contains reserved fleshy boss shapes. Under the action of the oil cylinder, the extrusion pin uses the 45° inclined tip or arc head protruding from the bottom end of the extrusion pin body to extrude the casting material inside the boss. The 45° inclined surface shape can be extruded in two directions by angle, so as to extrude the internal tissue of the die-casting along the 45-degree surface on both sides. When waiting for the movable mold to open, the fixed mold middle plate pushes out the part (i.e., aluminum alloy casting), and the mechanical gripper takes out the part. The formed part has an upward boss 22 (including a 45-degree inclined surface of the extruded inner hole).

[0030] In summary, the utility model discloses a die-casting structure for aluminum alloy castings, in which grooves are provided on the forming surface of the fixed mold core at positions corresponding to the screw holes, bosses are provided on the aluminum alloy castings located in the mold cavity at positions corresponding to the grooves, and one end of an extrusion pin is fixedly connected to the fixed mold core through an extrusion cylinder, and the other end passes through the fixed mold core and is located in the boss, so that after the die-casting is formed, the density of the casting around the boss can be increased under the action of the extrusion cylinder, and the quality of the screw holes around the boss can be improved, thereby effectively preventing the phenomenon of screw hole defects in the subsequent machining operations, reducing manufacturing costs, greatly improving production efficiency, and at the same time ensuring the subsequent machining quality of the die-castings, improving product quality and preventing air holes in the screw holes, thereby improving the qualified rate of products, greatly optimizing the existing structure, and reducing the manufacturing cost of on-site personnel to rework the warehouse.

[0031] Those skilled in the art should understand that they can implement variations based on the prior art and the above embodiments, which will not be described in detail here. Such variations do not affect the essence of the present invention and will not be described in detail here.

[0032] The above describes the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and the devices and structures that are not described in detail should be understood to be implemented in a common manner in the art; any technician familiar with the art can use the above-mentioned disclosed methods and technical contents to make many possible changes and modifications to the technical solutions of the present invention without departing from the scope of the technical solution of the present invention, or modify them into equivalent embodiments with equivalent changes, which does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention that do not depart from the content of the technical solution of the present invention are still within the scope of protection of the technical solution of the present invention.

Claims

1. An aluminum alloy die-casting structure, characterized in that: It includes a movable mold core, a fixed mold core, an extrusion pin and an extrusion cylinder; The fixed mold core and the movable mold core are in contact with each other and form a cavity, an aluminum alloy die-casting is formed in the cavity, and screw holes are formed on the aluminum alloy die-casting, a groove is provided on the molding surface of the fixed mold core at a position corresponding to the screw hole, and a boss is provided on the aluminum alloy die-casting corresponding to the groove; One end of the extrusion pin is fixedly connected to the fixed mold core through the extrusion cylinder, and the other end passes through the fixed mold core and is located in the boss.

2. The aluminum alloy die-casting structure according to claim 1, wherein: One end of the extrusion pin extending into the boss is a pointed head or an arc head.

3. The aluminum alloy die-casting structure according to claim 2, wherein: The angle of the pointed or arc head is 45°.

4. The aluminum alloy die-casting structure according to claim 1, wherein: The material of the extrusion pin is hot working die steel.

5. The aluminum alloy die-casting structure according to claim 4, characterized in that: The surface of the hot working die steel is covered with a composite nitriding layer.

6. The aluminum alloy die-casting structure according to claim 1, wherein: The extrusion pin is detachably fixed to the extrusion cylinder.

7. The aluminum alloy die-casting structure according to claim 1, wherein: The boss is arranged perpendicular to the screw hole.

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