Die casting molds

Abstract

In the flat region, the downstream region in the flow direction of molten metal relative to the protrusion is prevented from having insufficient filling of molten metal. [Solution] The die-casting mold comprises an injection port that communicates with the internal space of the die-casting mold and into which molten metal is poured, a projection having a shape that is convex toward the internal space, and a pair of flow straightening parts provided in a flat region that forms part of the internal space, located on the opposite side of the injection port from the projection, and sandwiching a virtual straight line extending from the injection port toward the projection, wherein the flow straightening parts have an elongated shape that becomes closer to a straight line as it moves away from the projection.

Description

Technical Field

[0001] The present disclosure relates to a die-casting mold.

Background Art

[0002] A technique of pouring molten metal into a die-casting mold to form a cast product has been conventionally known. Patent Document 1 discloses a die-casting mold having a main gate portion as a gate portion for pouring molten metal and a sub-gate portion located on the side of the main gate portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When forming a cast product, it is required to appropriately fill the die-casting mold with molten metal. However, in a die-casting mold provided with a protrusion having a shape that protrudes toward the internal space of the die-casting mold and a flat region constituting a part of the internal space, the poured molten metal collides with the protrusion and the flow of the molten metal diffuses. As a result, there is a possibility that the filling amount of the molten metal is insufficient in the downstream region of the flat region in the flow direction of the molten metal with respect to the protrusion.

Means for Solving the Problems

[0005] The present disclosure can be realized in the following forms.

[0006] According to one embodiment of the present disclosure, a die-casting mold is provided. This die-casting mold comprises an inlet communicating with the internal space of the die-casting mold and into which molten metal is poured; a projection having a shape that is convex toward the internal space; and a pair of flow straightening portions located in a flat region forming a part of the internal space, on the opposite side of the inlet from the projection, and provided so as to sandwich a hypothetical straight line extending from the inlet toward the projection, wherein the flow straightening portions have an elongated shape that approaches the straight line as it moves away from the projection. According to this embodiment of the die-casting mold, since the pair of flow straightening portions are located on the opposite side of the inlet from the projection and provided so as to sandwich a hypothetical straight line extending from the inlet toward the projection, the molten metal flowing in from the inlet can be directed toward the region of the flat region downstream of the projection in the direction of molten metal flow. Therefore, it is possible to suppress insufficient filling of molten metal in the region of the flat region downstream of the projection in the direction of molten metal flow. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic front view showing the internal structure of the die-casting mold in this embodiment. [Figure 2] This is an enlarged view showing the protrusion in this embodiment. [Figure 3] This is an enlarged view showing one of the pair of first rectifiers in this embodiment. [Modes for carrying out the invention]

[0008] A. Embodiments: Figure 1 is a schematic front view showing the internal structure of the die-casting mold 100 in this embodiment. The die-casting mold 100 is used in die-casting, in which molten metal is poured in at high speed and high pressure to integrally form a casting. In this embodiment, the die-casting mold 100 is used in so-called gigacasting, which integrally forms particularly large parts within die-casting.

[0009] The casting is formed to the same shape as the internal space of the die-casting mold 100. The type of casting is not particularly limited, but in this embodiment, the casting is a vehicle body part that constitutes the underbody of the vehicle. The material of the molten metal is not particularly limited, but an example is an aluminum alloy. For convenience of explanation, Figures 1 to 3 show the longitudinal and lateral directions. The longitudinal direction shown in Figure 1 coincides with the longitudinal direction of the vehicle in the casting (vehicle body part), and also coincides with the direction of gravity when filling the die-casting mold 100 with molten metal.

[0010] <Inlet 11> The die-casting mold 100 is equipped with an injection port 11 that communicates with the internal space of the die-casting mold 100. Molten metal is poured into the internal space of the die-casting mold 100 from the injection port 11. The injection port 11 is located at the rear end of the die-casting mold 100 and in the center in the left-right direction. In front of the injection port 11, there is a gate portion 14 that communicates with the injection port 11, and molten metal is filled into the casting section CA located in front of the gate portion 14 via the gate portion 14. The casting section CA is the part that forms the final casting. The length S1 in the front-rear direction and the length S2 in the left-right direction of the casting section CA are both approximately 1.5 m.

[0011] <Protrusion 12> Figure 2 is an enlarged view showing the projection 12 in this embodiment. The die-casting mold 100 is provided with a projection 12 having a shape that is convex toward the internal space of the die-casting mold 100. As a result, the final casting has a recess corresponding to the shape of the projection 12. The recess shape in the casting is used for positioning when assembling other parts to the casting. However, the use of the projection 12 in this disclosure is not limited to the above.

[0012] As shown in Figure 1, a flat region FL is provided in the center of the die-casting mold 100 in both the front-rear and left-right directions, forming part of the internal space of the die-casting mold 100. The flat region FL is the part that constitutes the passenger compartment of the vehicle in the final casting (vehicle body part). As shown in Figures 1 and 2, the projection 12 is located in the center of the rear end of the flat region FL in the left-right direction. More specifically, the projection 12 is provided at the rear end of the flat region FL, straddling the boundary of the flat region FL such that a part of it is located within the flat region FL. Due to the provision of such a projection 12, a portion of the molten metal injected from the injection port 11 collides with the projection 12, causing the flow of molten metal to diffuse. As a result, there is a risk that the amount of molten metal filling will be insufficient in the region of the flat region FL downstream of the projection 12 in the direction of molten metal flow. However, as will be described later, a pair of first flow straightening sections 13a and a pair of second flow straightening sections 13b straighten the diffused flow of molten metal, thereby suppressing insufficient filling of molten metal.

[0013] <First rectifier 13a, second rectifier 13b> As shown in Figure 1, the die-casting mold 100 includes two pairs of flow straightening sections for straightening the flow of molten metal, namely a pair of first flow straightening sections 13a and a pair of second flow straightening sections 13b. Both the pair of first flow straightening sections 13a and the pair of second flow straightening sections 13b are located on the opposite side of the inlet 11 from the projection 12, that is, in front of the projection 12. The pair of first flow straightening sections 13a are positioned in front of the pair of second flow straightening sections 13b. The pair of first flow straightening sections 13a and the pair of second flow straightening sections 13b are each positioned so as to straddle a hypothetical straight line CL extending from the inlet 11 toward the projection 12. Furthermore, each of the first flow straightening sections 13a and each of the second flow straightening sections 13b has an elongated shape that approaches the straight line CL as it moves away from the projection 12. Furthermore, an elongated shape refers to a shape in which the length of the rectifying section, which extends forward while approaching a straight line CL, is more than twice the width of the rectifying section in the left-right direction.

[0014] Figure 3 is an enlarged view showing one of the pair of first straightening sections 13a in this embodiment. As shown in Figure 3, the first straightening section 13a has a groove shape that is concave toward the internal space of the die-casting mold 100. The other first straightening section 13a of the pair and each second straightening section 13b have similar shapes. The pair of first straightening sections 13a and the pair of second straightening sections 13b reduce the difference in flow velocity of the molten metal in the flat region FL and have the function of resisting the flow of the molten metal and blocking the flow of the molten metal. Therefore, the pair of first straightening sections 13a and the pair of second straightening sections 13b can improve the uniformity of the filling speed of the molten metal in the flat region FL, and encourage the flow direction of the molten metal that flows in from the inlet 11 and diffuses at the projection 12 to be toward the downstream region of the molten metal flow direction relative to the projection 12 within the flat region FL. Therefore, in the flat region FL, it is possible to suppress insufficient filling of molten metal in the region downstream of the projection 12 in the flow direction of the molten metal.

[0015] The dimensions of each first flow straightening section 13a and each second flow straightening section 13b are not particularly limited, but as an example, the length L of each first flow straightening section 13a extending forward while approaching a straight line CL is 180 mm, the width W of each first flow straightening section 13a in the left-right direction is 5 mm, and the depth D of the groove of each first flow straightening section 13a is 2 mm. The length of each second flow straightening section 13b extending forward while approaching a straight line CL is 88 mm, and the length of the second flow straightening section 13b is shorter than the length L of the first flow straightening section 13a. The width and depth of each second flow straightening section 13b are equal to the width W and depth D of each first flow straightening section 13a.

[0016] Furthermore, the final casting will have convex shapes corresponding to the groove shapes of the first and second flow straightening sections 13a and 13b. These convex shapes in the casting function as bead sections that improve the strength of the casting. In addition, each of the first and second flow straightening sections 13a and 13b has rounded ends on their elongated shapes. This allows the casting to be easily removed from the die-casting mold 100 after it has been formed.

[0017] According to the die-casting mold 100 described above, both the pair of first rectifying portions 13a and the pair of second rectifying portions 13b are located on the side opposite to the injection port 11 with respect to the protruding portion 12, and are provided so as to sandwich a virtual straight line CL extending from the injection port 11 toward the protruding portion 12. Therefore, the molten metal flowing in from the injection port 11 can be urged to flow toward the downstream region in the flow direction of the molten metal with respect to the protruding portion 12 in the flat region FL. For this reason, it is possible to suppress a shortage in the filling amount of the molten metal in the downstream region in the flow direction of the molten metal with respect to the protruding portion 12 in the flat region FL.

[0018] In addition, since the die-casting mold 100 includes two pairs of rectifying portions, compared with a configuration in which only one pair of rectifying portions is provided in the die-casting mold 100, the flow direction of the molten metal diffused at the protruding portion 12 can be more effectively urged to flow toward the downstream region in the flow direction of the molten metal with respect to the protruding portion 12 in the flat region FL in two stages by the second rectifying portion 13b and the first rectifying portion 13a.

[0019] Also, although the molten metal that has collided with the protruding portion 12 diffuses over a wider range as it moves away from the protruding portion 12 in the forward direction, the length L of each first rectifying portion 13a provided in front of each second rectifying portion 13b is configured to be longer than the length of each second rectifying portion 13b. Therefore, the flow direction of the molten metal diffused at the protruding portion 12 can be more effectively urged to flow toward the downstream region in the flow direction of the molten metal with respect to the protruding portion 12 in the flat region FL.

[0020] B. Other Embodiments: (B1) In this embodiment, the protrusion 12 was provided at the center in the left - right direction among the lower ends of the flat region FL. However, the present disclosure is not limited to this. The protrusion 12 may be provided near the center in the front - rear direction and the left - right direction of the flat region FL, or may be provided in a region outside the flat region FL, such as between the injection port 11 and the flat region FL. Also, two or more protrusions 12 may be provided. In this case, a pair of rectifying portions may be provided for one protrusion 12, or a pair of rectifying portions may be provided for two or more protrusions 12, and the pair of rectifying portions may be configured to rectify the flow of the molten metal diffused at each protrusion 12.

[0021] (B2) In this embodiment, each first rectifying portion 13a and each second rectifying portion 13b had a groove shape that was concave toward the internal space of the die - casting mold 100. However, the present disclosure is not limited to this. Each first rectifying portion 13a and each second rectifying portion 13b only need to be able to rectify the flow of the molten metal. For example, each first rectifying portion 13a and each second rectifying portion 13b may have a shape that is convex toward the internal space of the die - casting mold 100. Also, each first rectifying portion 13a and each second rectifying portion 13b may have a shape such that its depth changes continuously or discontinuously in the length direction.

[0022] (B3) In this embodiment, the die - casting mold 100 included a pair of first rectifying portions 13a and a pair of second rectifying portions 13b. However, the present disclosure is not limited to this. The die - casting mold 100 may be configured such that only one set of a pair of rectifying portions is provided, or may be configured such that three or more sets of a pair of rectifying portions are provided. Also, the length of each first rectifying portion 13a was configured to be longer than the length of each second rectifying portion 13b. However, the present disclosure is not limited to this. The length of each first rectifying portion 13a and the length of each second rectifying portion 13b may be the same.

[0023] (B4) In this embodiment, the dimensions of each of the pair of first rectifiers 13a are the same, and the dimensions of each of the pair of second rectifiers 13b are the same, but the disclosure is not limited thereto. The dimensions of each of the pair of first rectifiers 13a are different, and the dimensions of each of the pair of second rectifiers 13b are different.

[0024] This disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from its spirit. For example, the technical features in the embodiments corresponding to the technical features in each form described in the summary of the invention can be replaced or combined as appropriate in order to solve some or all of the above-described problems, or to achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate. [Explanation of Symbols]

[0025] 11…Inlet, 12…Protrusion, 13a…First flow straightening section, 13b…Second flow straightening section, 14…Gate section, 100…Die-casting mold, CA…Casting section, FL…Flat area, CL…Straight line, W…Width, L…Length, D…Depth

Claims

[Claim 1] It is a die-casting mold, The inlet is connected to the internal space of the die-casting mold and into which molten metal is poured, A projection having a shape that is convex toward the internal space, In a flat region forming a part of the internal space, a pair of flow straightening portions are provided, located on the opposite side of the inlet from the projection, and sandwiching a virtual straight line extending from the inlet toward the projection. The die-casting mold has an elongated shape in which the rectifying portion approaches the straight line as it moves away from the projection.

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