JP4809160B2 - Casting mold and manufacturing method thereof - Google Patents

Description

  The present invention relates to a casting mold for forming a cast product by injecting molten metal in which a metal is melted into a mold, and a method for manufacturing the same.

2. Description of the Related Art Conventionally, casting molds such as molds and sand molds for forming cast products by pouring molten metal in which a metal such as iron, aluminum, or lead is poured have been used.
For example, Patent Document 1 discloses a casting mold in which a gas trap, a slag trap, and a foreign matter trap are formed for the purpose of removing a gas contained in a molten metal and a foreign matter having a small specific gravity.

Here, a gas trap is formed upward, and a foreign matter trap for removing foreign matter having a small specific gravity is provided above the slag trap, so that the molten metal is included in the molten metal in the process of rectifying in the side runner. While removing the gas, the foreign matter having a small specific gravity driven into the slag trap can be collected in the foreign matter trap after separating the slag.
Japanese Patent Laid-Open No. 5-305387 (published on November 19, 1993)

However, the conventional casting mold has the following problems.
That is, in the casting mold disclosed in the above publication, slag traps and foreign matter traps are formed on the side of the runner that introduces the molten metal into the cavity space to remove gas contained in the molten metal and foreign matters having a small specific gravity. Yes. For this reason, for example, when a casting mold such as a sand mold is used, in the cavity space in the mold, if a part of the inner surface of the mold forming the cavity space is chipped and the foreign substance is generated, the foreign substance is removed. It is difficult to do.

  An object of the present invention is to provide a casting mold capable of removing foreign matters generated inside and outside the cavity space and effectively preventing the occurrence of casting defects due to the inclusion of foreign matters, and a method for manufacturing the same.

The casting mold according to the first invention includes a cavity portion, a gate, a runner, and a foreign matter removal space portion. The cavity portion forms a space corresponding to the product portion in the mold. The spout pours molten metal into the cavity. The runner communicates the cavity and the gate. The foreign substance removal space communicates with the cavity so as to guide the molten metal flowing into the cavity from the runway to the outside of the cavity, and at the side of the cavity in the posture when pouring the molten metal into the cabty. Is formed . And the foreign material removal space part has the opening connected with a cavity part in the position facing with respect to the advancing direction of the flow of the molten metal inject | poured in the cavity part via the runner.

Here, the foreign matter removal space that guides the molten metal, which is injected from the gate formed in the casting mold and flows into the cavity corresponding to the product portion through the runner, to the outside of the cavity, is excluded from the runner It is formed in the peripheral part of the cavity part.
Here, the cavity portion is a space corresponding to the product portion, and includes a hot water portion provided at a position close to the product portion in order to replenish the molten metal for volume contraction when the molten metal solidifies. The foreign substance removal space is a closed space in which only the communication part with the cavity is opened.

  Usually, in such a casting mold, a gas trap or a foreign matter trap is provided in the middle of a runway communicating with the cavity portion in order to prevent foreign matter such as gas and oxide from flowing into the space of the cavity portion. It is arranged. However, in such a configuration, foreign matters mixed in the molten metal before flowing into the cavity can be removed, but foreign matters mixed in the molten metal cannot be removed when the molten metal is filled in the cavity. In particular, when a sand mold or the like is used as a casting mold, when the molten metal is filled in the cavity formed in the sand mold, a part of the sand mold may be lost and mixed as foreign matter into the molten metal.

Therefore, in the casting mold of the present invention, the foreign substance removal space portion that guides the molten metal to the outside of the cavity portion while the molten metal flowing into the cavity portion from the gate through the runner is filled into the cavity portion, It is provided around.
Thereby, in the process in which the molten metal that has flowed from the gate through the runner is filled in the cavity, foreign matter including gas and inclusions mixed in the molten metal can be guided to the foreign matter removal space. As a result, it is possible to fill the cavity with molten metal in a state where the foreign matter is retained in the foreign matter removal space. Therefore, it is possible to effectively generate casting defects when foreign matter generated inside and outside the cavity portion enters the cavity portion. Can be prevented.

The casting mold according to the second invention is the casting mold according to the first invention, and is a sand mold.
Here, a sand mold is used as a casting mold, which is low in cost and easy to form as compared with a mold.
In general, the sand mold is formed by solidifying sand such as mountain sand or synthetic sand. Therefore, when the molten metal is poured from the gate through the runner, the flow of the molten metal in the cavity portion causes a part of the cavity portion. There is a possibility that foreign matter may be generated due to chipping.
In the casting mold of the present invention, even when foreign matter is generated in the cavity portion into which the molten metal is poured, the foreign matter can be sent out to the foreign matter removal space portion outside the cavity portion. As a result, even when casting is performed using a sand mold, it is possible to effectively prevent the occurrence of casting defects due to the entry of foreign matter into the cavity.

  A casting mold according to a third invention is the casting mold according to the first or second invention, wherein the foreign matter removal space portion is connected to the cavity portion via a communication portion having a smaller cross-sectional area than the foreign matter removal space portion. Communicate.

Here, the foreign substance removal space portion and the cavity portion communicate with each other via a communication portion having a small cross-sectional area.
Here, the cross-sectional area of the communication portion means a cross-sectional area when cut by a plane along the direction intersecting the molten metal inflow direction.
As a result, when the molten metal is filled in the cavity, the staying of the molten metal in the foreign matter removal space is generated by the communication portion having a small cross-sectional area, so that the gas, oxide, etc. that has flowed into the foreign matter removal space can be removed. It is possible to suppress the contained foreign matter from flowing out of the foreign matter removal space. As a result, it is possible to prevent foreign matter from being captured by the foreign matter removal space and flowing out to the cavity, and to effectively prevent the occurrence of casting defects due to foreign matter contamination.

A casting mold according to a fourth aspect of the present invention is the casting mold according to any one of the first to third aspects of the present invention, wherein the foreign matter removal space portion is a portion of the cavity portion in a posture when pouring molten metal into the cavity portion. It is formed on the side.
Here, the foreign substance removal space is formed on the side surface side of the cavity portion in the direction when the molten metal is poured into the mold.
Thus, in the process of filling the molten metal injected into the cavity, the molten metal can be guided to the foreign substance removal space formed on the side surface of the cavity with a flow before the molten metal is filled. it can. As a result, the foreign matter contained in the molten metal can be effectively guided to the foreign matter removal space and captured, and the occurrence of casting defects due to the inclusion of foreign matter can be more effectively prevented.

A casting mold according to a fifth aspect of the present invention is the casting mold according to any one of the first to fourth aspects of the present invention, wherein the foreign matter removal space portion is at a position lower than the connection portion between the cavity portion and the runner. Is formed .

Here, at a position lower than the connection portion between the cavity and the runner to form a cross-removal empty.

A casting mold according to a sixth aspect of the present invention is the casting mold according to any one of the first to fifth aspects of the present invention, wherein the communication portion that connects the foreign substance removal space portion and the cavity portion has a curved portion. It is formed to include.
Here, the foreign substance removal space is connected to the cavity through a communication part including a loose curved part.

  As a result, when the foreign substance removal space is arranged close to the cavity part, the foreign substance removal space part is formed so as to be separated from the cavity part as the product part by providing a curved part in the communication part. can do. In addition, since the bent shape of the communication portion is curved, the molten metal can be smoothly guided to the foreign matter removing space without hindering the flow of the molten metal. As a result, it is possible to avoid the heat and the like in the foreign substance removal space from adversely affecting the cavity part that is the product part.

  A casting mold manufacturing method according to a seventh invention is a casting mold manufacturing method according to any one of the first to sixth inventions, and includes a first step and a second step. . And in a 1st step, the hot water flow simulation regarding the flow of a molten metal is performed about a casting mold. In the second step, the arrangement of the foreign matter removal space with respect to the cavity is determined based on the result of the hot water flow simulation.

Here, based on the result of performing the molten metal flow simulation for each casting mold, a location where a casting defect due to foreign matter is likely to occur is specified, and then the position of the foreign matter removal space portion with respect to the cavity portion is determined.
As a result, the foreign matter removal space can be formed in the vicinity of the location where casting defects are likely to concentrate due to the retention of foreign matter, so that by introducing the foreign matter to the foreign matter removal space, The occurrence of casting defects can be effectively prevented.

  According to the casting mold of the present invention, foreign matters generated inside and outside the cavity space can be removed, and the occurrence of casting defects due to foreign matter mixing can be effectively prevented.

[Embodiment 1]
A sand mold (casting mold) 10 according to an embodiment of the present invention will be described below with reference to FIGS.
[Configuration of sand mold 10 as a whole]
The sand mold 10 according to the present embodiment melts and casts a metal such as iron, aluminum, lead, or an alloy thereof, for example, to form a product P (see FIG. 2) as a cast product mounted on a construction machine. As shown in FIG. 1, the mold for casting is used for the product molding part 11 including the product part Pa, the injection part 12, sand stopper molding parts (foreign matter removal space parts) 14 and 15, It has.

(Product molding part 11)
The product forming part 11 is located at a position close to the product part Pa in order to replenish the product part Pa forming the cavity space (cavity part) S (see FIG. 7) and the volume shrinkage when the melt solidifies. And provided hot water 11a to 11e.
The product portion Pa forms a cavity space S in the interior thereof in accordance with the shape of the product P shown in FIG.

The hot water 11a is provided in the upper part of the product part Pa, and the hot waters 11b to 11e are provided in the vicinity of the four corners on the side of the product part Pa, and the molten metal injected into the mold is solidified. Accumulate molten metal to compensate for shrinkage.
(Injection unit 12)
The injection part 12 is provided on the side of the product part Pa in order to inject molten metal into the product part Pa and the hot water 11a to 11e, and has a gate 12a and a runner 12b.

The gate 12a is formed in the front-end | tip part of the runner 12b, and the molten metal to which the pressure for inject | pouring into a type | mold was poured into.
The runner 12b is a tubular part that guides the molten metal poured from the gate 12a toward the product part Pa, and communicates with the cavity space S of the product part Pa from the side.
(Sand stop molding part 14, 15)
The sand stopper molding parts 14 and 15 are portions where inclusions (foreign matter) M (see FIG. 3) such as gas, oxide, sand, etc. in the product P are likely to concentrate based on the result of the hot water flow simulation described later. The molten metal containing the inclusion M flows into the inside, and forms a space for molding the sand stoppers 14a and 15a. And the sand stop shaping | molding parts 14 and 15 are connected via the dam (communication part) 16a, 16b with respect to the cavity space S formed in the inside of the product part Pa. FIG. For this reason, the molten metal injected into the cavity space S from the gate 12a via the runner 12b passes through the weirs 16a and 16b formed on the side of the product part Pa in the posture of the sand mold 10 at the time of injection. The cavity space S is filled while flowing into the stop molding portions 14 and 15.

As shown in FIGS. 2 and 3, the sand stoppers 14 a and 15 a are provided on the side of the product P, and as shown in FIG. 3, the inclusion containing the inclusion M is retained by retaining the molten metal. Capture M. In FIG. 3, only the sand stopper 14a side is shown, but the same applies to the sand stopper 15a side.
As shown in FIGS. 3 and 7, the weirs 16a and 16b have a cavity area S corresponding to the product portion Pa and sand retaining molding portions 14 and 15 in which the cross-sectional area by the plane intersecting the molten metal flow direction is as shown in FIGS. It is formed so as to be smaller than the cross-sectional area. That is, the molten metal that has flowed into the cavity space S from the runner 12a flows into the sand stopper molding portions 14 and 15 through narrow passages (weirs 16a and 16b). Thus, by changing the cross-sectional area of the space through which the molten metal flows, it is possible to cause the molten metal to stay inside the sand stop molding portions 14 and 15 as will be described later, and therefore the inclusion M present in the molten metal. Can be attached to the wall surfaces of the sand stoppers 14a and 15a and captured.

  Further, as shown in FIG. 7, the weirs 16a and 16b are opened to the front in the traveling direction of the molten metal flowing into the cavity space S formed in the product portion Pa from the gate 12a via the runner 12b. It is preferable. As a result, the molten metal that has flowed into the cavity space S is actively guided into the sand stopper molding portions 14 and 15, so that the molten metal is filled in the cavity space S and the like in the sand stopper molding portions 14 and 15. , It is possible to effectively prevent the occurrence of casting defects in the product P caused by the inclusions M by capturing the molten metal in the initial stage of inflow including a lot of inclusions M.

<Simulation of hot water flow in the sand-resin molding parts 14 and 15>
As described above, the sand mold 10 of the present embodiment captures the inclusion M such as sand, oxide, gas, etc., from which a part of the sand mold has been peeled off based on the result of the molten metal flow simulation to be described later. Sand stop molding portions 14 and 15 for preventing inflow into the cavity space S corresponding to Pa are provided.

Here, FIGS. 4 (a) to 6 (b) show the results of simulation of the molten metal flow direction in the sand retaining molding portions 14 and 15 when the sand retaining molding portions 14 and 15 are provided. Will be described.
In addition, although the sand stopper molding part 15 is mentioned as an example and demonstrated here, since the same result is obtained also in the other sand stopper molding part 14, the description is abbreviate | omitted here.

Moreover, the hot water flow simulation described here employs a method of marking the molten metal in the initial stage of inflow and specifying the vortex generation site by the velocity vector for specifying the filling path and the staying site.
First, on the basis of the XYZ axes shown in FIG. 4A and the like, the hot water flow direction in each plane was examined by simulation. In the XY plane, the weir 16b was passed through the cavity space S from the runner 12b. As shown in FIGS. 4 (a) and 4 (b), it has been found that the molten metal that has flowed into the sand stopper molding part 15 swirls from below to flow upward.

Similarly, in the XZ plane, the molten metal that has flowed into the sand-resin molding part 15 via the weir 16b from the runner 12b through the cavity space S is shown in FIGS. 5 (a) and 5 (b). As shown, it turned out to swirl to the left and right to flow in a spiral.
Similarly, in the YZ plane, the molten metal that has flowed from the runner 12b through the cavity space S and into the sand stopper molding part 15 through the weir 16b is shown in FIGS. 6 (a) and 6 (b). Further, it was found that after hitting the opposite surface of the surface on which the weir 16b was formed in the sand-resin molding part 15, it rose and swirled left and right to flow in a spiral shape.

  As a result of the above simulation, the molten metal that has flowed from the runner 12b through the cavity space S and into the sand stopper molding portions 14 and 15 through the weirs 16a and 16b is spirally formed in the sand stopper molding portions 14 and 15. Stay inside while turning. Accordingly, the molten metal that has flowed into the sand stopper molding portions 14 and 15 is prevented from flowing back into the cavity space S, so that the inclusion M contained in the molten metal that has flowed into the sand stopper molding portions 14 and 15 is contained in the cavity space. It is possible to prevent the remaining in S.

Furthermore, even in a site where high strength and high rigidity are required, a strength and rigidity decrease due to the presence of the inclusion M is provided by providing a sand stop molding portion so that the inclusion M does not stay around it. Can be prevented.
<Method for producing sand mold 10>
In the present embodiment, the above-described sand mold 10 is formed according to the flowchart shown in FIG.

That is, first, in step S1, a casting mold (sand mold 10) is selected according to the shape of the product P to be molded.
Next, in step S2, a hot water flow simulation for examining the behavior of the molten metal injected into the mold is performed for the sand mold 10 selected in step S1.
Next, in step S3, based on the result of the molten metal flow simulation in step S2 (see FIG. 13A to FIG. 14), there is a high possibility that inclusions M concentrate and casting defects occur (defect occurrence). (Predicted part) is specified.

  Next, in step S4, the sand stoppers 14a and 15a are formed at positions adjacent to the cavity space S based on the position of the predicted defect occurrence site specified in step S3 and the behavior of the molten metal in the cavity space S. The position of the sand stop molding parts 14 and 15 is determined. Specifically, the sand stop molding portions 14 and 15 and the weirs 16a and 16b are arranged so that the opening faces in the direction opposite to the molten metal flowing direction in the vicinity of the portion where the casting defect is likely to occur.

Next, in step S5, the sand mold 10 provided with the sand stop molding portions 14 and 15 determined in step S4 is molded at a specific position in the sand mold 10 selected in step S1 according to the shape of the product P. .
As described above, by determining the position where the sand stoppers 14a and 15a are provided using the result of the molten metal flow simulation, sand for capturing inclusions M in the vicinity of a portion where a casting defect is likely to occur. The stop molding parts 14 and 15 can be provided. As a result, it is possible to effectively prevent inclusions M from being collected in the sand stoppers 14a and 15a and causing casting defects on the surface of the product P or the like.

[Comparative Example 1]
Here, in order to verify the effect of preventing the occurrence of casting defects of the sand mold 10 shown in FIGS. 1 to 7, the structure of the sand mold as a comparative example for molding the product P having the same shape using FIGS. Is described as follows.
As shown in FIG. 12, the sand mold 100 of the comparative example is a casting mold for molding a product P having the same shape as the sand mold 10 of the present embodiment, and includes a product molding part 101 and an injection part 102. ing.

The product molding part 101 is a part corresponding to the product molding part 11 of the sand mold 10 of the present embodiment, and has the product part Pa and the hot waters 101a to 101e similarly to the product molding part 11. .
The injection part 102 is a part corresponding to the injection part 12 of the sand mold 10 of the present embodiment, and has a gate 102a and a runner 102b, like the injection part 12.

Here, in the sand mold 100 of the comparative example, in the portion A shown in FIG. 12, as shown in FIG. 13A, the molten metal stays in a part of the product portion Pa. Thus, since the inclusion M gathers in large quantities in the molten metal which stayed in the product part Pa, there is a high possibility that a casting defect will occur.
Similarly, also in B part shown in FIG. 12, as shown in FIG.13 (b), stagnation of molten metal generate | occur | produces in a part of product part Pa, and the casting defect resulting from the presence of the inclusion M in this part. Is likely to occur.

As a result, in the product P formed by the sand mold 100 of the comparative example in which no sand stopper is provided, as shown in FIG. 14, the inclusion M is concentrated on a specific part, and thus a casting defect occurs. .
[Features of sand mold 10]
(1)
The sand mold 10 of the present embodiment is a mold for pouring and solidifying molten metal to form a product P having an arbitrary shape. As shown in FIG. 1, a cavity space S corresponding to the product P is formed inside. The product forming part 11 formed in the mold, the injection part 12 including the gate 12a and the runner 12b, and the sand stop forming part 14 for guiding the molten metal flowing into the cavity space S through the runner 12b to the outside of the cavity space S. , 15.

  Thereby, the molten metal that has flowed into the cavity space S from the gate 12a through the runner 12b can be actively guided into the sand stopper molding portions 14 and 15. For this reason, for example, even when gas or oxide originally contained in the molten metal or a part of the inside of the sand mold 10 is missing in the cavity space S and inclusion M such as sand is generated, the molten metal is Prior to filling in S, the molten metal containing inclusions M can be introduced into the sand-stop molding parts 14 and 15. As a result, the inclusions in the sand stoppers 14a and 15a outside the cavity space S are provided by providing the sand stopper molding portions 14 and 15 in the vicinity of the portion where the casting defect due to the inclusion M is likely to occur. It is possible to effectively prevent the occurrence of casting defects by feeding M.

(2)
In the present embodiment, as shown in FIG. 1 and the like, a sand mold 10 is used as a casting mold.
Thereby, for example, even in the case where inclusions M such as sand, which are part of the sand mold 10 generated after the pressure or flow of the molten metal when the molten metal is poured into the cavity space S, are generated in the cavity space S. These inclusions M can be guided into the sand stop molding portions 14 and 15. As a result, the presence of inclusions M in the sand stoppers 14a and 15a can reduce the probability that the inclusions M are present on the surface of the product P, so that the occurrence of casting defects is greatly reduced compared to the conventional case. can do.

(3)
In the sand mold 10 of the present embodiment, as shown in FIGS. 2, 3 (a), and 3 (b), the cavity space S and the sand are used as communication portions that connect the cavity space S and the sand stopper molding portions 14 and 15. Weirs 16a and 16b having a smaller cross-sectional area than the stop forming portions 14 and 15 are provided.
As a result, the molten metal that has once flowed from the cavity space S into the sand stopper molding portions 14 and 15 is prevented from flowing back into the cavity space S by staying in a vortex in the sand stopper molding portions 14 and 15. can do. As a result, it is possible to improve the capture effect of the inclusions M in the sand stop molding portions 14 and 15 and more reliably prevent the occurrence of casting defects.

(4)
In the sand mold 10 of the present embodiment, as shown in FIG. 1 and the like, sand stop molding portions 14 and 15 are provided on the side in the posture of the sand mold 10 when molten metal is poured.
As a result, the molten metal that has flowed from the gate 12a into the cavity space S via the runner 12b is actively guided into the sand stopper molding portions 14 and 15 before the cavity space S is filled with the molten metal. can do. As a result, the molten metal containing inclusions M is effectively guided into the sand-stop molding parts 14 and 15 to prevent the occurrence of casting defects caused by the inclusions M on the surface of the product P. Can do.

(5)
In the sand mold 10 of this embodiment, as shown in FIG. 1 and FIG. 7 and the like, the opening portions of the sand stop molding portions 14 and 15 are located in front of the molten metal injected from the gate 12a in the cavity space S in the traveling direction. It arrange | positions so that the opening of the weirs 16a and 16b which become may face.
Thereby, the molten metal containing inclusions M can be actively guided into the sand stopper molding parts 14 and 15 along the natural flow without hindering the flow of the molten metal flowing into the cavity space S. . As a result, it is possible to prevent the inclusion M from remaining on the cavity space S side, which is the product P side, and to effectively prevent the occurrence of casting defects.

(6)
In the method for manufacturing the sand mold 10 of the present embodiment, as shown in FIG. 8, a hot water flow simulation is performed on a mold selected in accordance with the shape of the product P to be molded, and the sand stoppers 14a, The position of 15a is determined.
As a result, the portion where the inclusions M in the cavity space S are concentrated and a casting defect is likely to occur is specified, and the sand stopper molding portions 14 and 15 are provided in the vicinity thereof, thereby existing in a specific portion. Most of the inclusions M can be guided into the sand stop moldings 14 and 15. As a result, it is possible to effectively arrange the sand stop molding portions 14 and 15 and prevent the occurrence of casting defects more effectively.

[Embodiment 2]
A sand mold (casting mold) 20 according to another embodiment of the present invention will be described below with reference to FIGS. 9 to 10B.
In addition, the sand mold 20 of this embodiment is not around the cavity space corresponding to the product parts Pa1 and Pa2, but when the molten metal solidifies, as shown in FIGS. 9, 10 (a) and 10 (b). The sand mold 10 is different from the sand mold 10 of the first embodiment in that a sand stopper molding portion 24 is provided around a portion of the hot water 21c for storing molten metal for compensating for shrinkage. For this reason, in this embodiment, the space formed in the hot water 21c is also included as the cavity space.

  In the same manner as the sand mold 10 of the first embodiment, the sand mold 20 forms, for example, two products P1 and P2 (see FIG. 11A and FIG. 11B) as cast products mounted on a construction machine. As shown in FIG. 9, a product molding part 21 including product parts Pa1, Pa2, an injection part 22, a sand stop molding part (foreign matter removal space part) 24, It has.

(Product molding part 21)
The product molding part 21 is provided at a position close to the product part Pa2 in order to replenish the product parts Pa1 and Pa2 that form cavity spaces (cavity parts) therein and the volume shrinkage when the melt solidifies. And hot water 21c.
The product portions Pa1 and Pa2 form a cavity space inside according to the shape of the products P1 and P2 shown in FIGS. 11 (a) and 11 (b).

The hot water 21c is provided at a position adjacent to the product part Pa2, and stores the molten metal to compensate for the shrinkage of the molten metal when the molten metal injected into the mold solidifies.
(Injection unit 22)
The injection part 22 is provided on the side of the product parts Pa1 and Pa2 in order to inject the molten metal into the product parts Pa1 and Pa2 and the hot water 21c, and has a gate 22a and a runner 22b. Yes.

The sprue 22a is formed at the front end portion of the runner 22b, and a molten metal to which pressure for pouring into the mold is applied is poured.
The runner 22b is a tubular part that guides the molten metal poured from the spout 22a to the product parts Pa1 and Pa2, respectively, and communicates with the cavity space of the product parts Pa1 and Pa2 from the side. .

(Sand stop molding part 24)
Similar to the sand mold 10 described above, the sand-resin molding part 24 is provided around a portion where inclusions M (see FIG. 9) in the products P1 and P2 are expected to concentrate based on the result of the hot water flow simulation. ing. And as shown in Fig.10 (a) and FIG.10 (b), the sand stop shaping | molding part 24 is connected via the weir (communication part) 26 connected to the part which the runway 22b and the hot water supply 21c communicate. It communicates with the hot water 21c and the runway 22b. For this reason, the molten metal injected from the gate 22a into the space of the hot water 21c via the runner 22b passes through the weir 26 formed on the side of the hot water 21c in the posture of the sand mold 20 at the time of pouring. While flowing into the stop molding part 24, the cavity spaces inside the product parts Pa1, Pa2 are filled.

As shown in FIGS. 10 (a) and 10 (b), the sand-resist molding part 24 is provided on the side with respect to the product parts Pa1 and Pa2, and as shown in FIG. Inclusion M is captured by retaining the molten metal.
As shown in FIGS. 10 (a) and 10 (b), the weir 26 has an area of a cross section by a plane intersecting the molten metal flow direction, and the cavity space inside the product parts Pa1 and Pa2 and sand-resist molding. It is formed to be smaller than the cross-sectional area of the portion 24. As a result, in the same manner as the sand retaining molding portions 14 and 15 of the sand mold 10 described above, it is possible to cause the stagnation of the molten metal in the sand retaining molding portion 24, so that the inclusion M present in the molten metal is sand retaining molded. It can be attached to the wall surface in the part 24 and captured. Further, as shown in FIG. 10 (b), the weir 26 is connected to the sand stopper molding portion 24 while forming a gently curved portion from the communicating portion with the hot water 21c. Accordingly, it is possible to prevent the sand stopper molding part 24 from being unnecessarily close to the product part Pa2 and to prevent the product part Pa2 from being affected by the heat of the sand stopper molding part 24 or the like. it can. Furthermore, by providing the curved portion, the degree of freedom of the arrangement of the sand stopper molding portion 24 can be improved.

In the sand mold 20 of the present embodiment, as described above, the sand stop molding portion 24 is provided not at the side of the product parts Pa1 and Pa2, but at a portion connected from the runner 22b to the hot water 21c.
Even in this case, since the molten metal flows quickly around the hot water 21c, the molten metal containing foreign substances such as gas and oxide can be efficiently guided into the sand stopper molding portion 24. For this reason, as in the sand mold 10 described above, also in the sand mold 20, as shown in FIG. 9, by concentrating the inclusions M in the sand stop molding part 24, the inclusions M in the product parts Pa <b> 1, Pa <b> 2. The occurrence of casting defects due to mixing can be effectively prevented.

Note that, similarly to the sand mold 10 described above, the sand mold 20 of the present embodiment also has an arrangement of the sand stop molding portion 24 in the vicinity of a portion where casting defects are likely to occur based on the simulation results shown in FIG. Just decide.
[Comparative Example 2]
Here, in order to verify the effect of preventing the occurrence of casting defects in the sand mold 20 shown in FIGS. 9 to 10B, the configuration of the sand mold as a comparative example will be described with reference to FIG.

As shown in FIG. 15, the sand mold 120 of the comparative example is a casting mold for molding products P1 and P2 having the same shape as the sand mold 20 of the present embodiment, and includes a product molding part 121, an injection part 122, It has.
The product molding part 121 is a part corresponding to the product molding part 21 of the sand mold 20 of the present embodiment, and has product parts Pa1 and Pa2 and a hot water 121c in the same manner as the product molding part 21. .

The injection part 122 is a part corresponding to the injection part 22 of the sand mold 20 of the present embodiment, and has a gate 122a and a runner 122b, like the injection part 22.
Here, in the sand mold 120 of the comparative example, in the part C shown in FIG. 15, the molten metal stays in a part of the product part Pa2, and a large amount of inclusions M are collected. There is a high risk of defects.

As a result, in the product Pa2 formed by the sand mold 120 of the comparative example in which no sand stopper is provided, as shown in FIG. 15, the inclusion M is concentrated on a specific part, thereby causing a casting defect. It turns out that fear is high.
[Features of sand mold 20]
(1)
The sand mold 20 of the present embodiment is a mold for casting molten metal and solidifying it to form products P1 and P2 of any shape, and as shown in FIG. 9, cavities corresponding to the products P1 and P2 The product forming part 21 forming the space inside, the injection part 22 including the gate 22a and the runner 22b, and the molten metal flowing into the cavity space of the hot water 21c via the runner 22b is guided out of the cavity space. And a sand stop molding part 24.

  Thereby, the molten metal that has flowed from the gate 22a through the runner 22b into the cavity space of the hot water 21c can be actively guided into the sand stopper molding portion 24. Therefore, for example, even when gas or oxide originally contained in the molten metal or a part of the inside of the sand mold 20 is missing in the cavity space and the inclusion M such as sand is generated, the molten metal remains in the cavity space. The molten metal containing the inclusions M can be guided into the sand stopper molding portion 24 before being filled with. As a result, by providing the sand-resin molding part 24 in the vicinity of a site where a casting defect due to the inclusion M is likely to occur, the inclusion M is placed in the sand-resin molding part 24 outside the cavity space S. It is possible to effectively prevent casting defects from occurring.

(2)
In this embodiment, as shown in FIG. 9 and the like, a sand mold 20 is used as a casting mold.
As a result, for example, inclusions M such as sand, which are part of the sand mold 20 generated after the pressure and flow of the molten metal when the molten metal is poured into the cavity space, are generated in the cavity space in the hot water 21c. Even in this case, these inclusions M can be guided into the sand stop molding portion 24. As a result, the presence of the inclusion M in the sand stopper can reduce the probability that the inclusion M exists on the surfaces of the products P1 and P2, etc., so that the occurrence of casting defects is significantly reduced compared to the conventional case. be able to.

(3)
In the sand mold 20 of the present embodiment, as shown in FIGS. 10A and 10B, the cavity space and the sand-resist molding are used as communication portions that connect the cavity space in the hot water 21 c and the sand-reseal molding portion 24. A weir 26 having a smaller cross-sectional area than the portion 24 is provided.
As a result, the molten metal that has once flowed into the sand retaining molding portion 24 from the cavity space in the feeder 21 c stays in a vortex shape in the sand retaining molding portion 24, thereby backflowing into the cavity space in the feeder 21 c. Can be prevented. As a result, it is possible to improve the effect of capturing the inclusions M in the sand stopper molding part 24 and more reliably prevent the occurrence of casting defects.

(4)
In the sand mold 20 of the present embodiment, as shown in FIG. 9 and the like, a sand stop molding portion 24 is provided on the side of the posture of the sand mold 20 when pouring molten metal.
As a result, the molten metal that has flowed into the cavity space from the gate 22a via the runner 22b is positively sanded before the product spaces Pa1 and Pa2 and the cavity space in the hot water 21c are filled with the molten metal. It can be guided into the molding part 24. As a result, the molten metal containing inclusions M is effectively guided into the sand-resin molding part 24 to prevent the occurrence of casting defects caused by the inclusions M on the surfaces of the products P1 and P2. Can do.

(5)
In the sand mold 20 of the present embodiment, as shown in FIGS. 10 (a) and 10 (b), an opening portion of the sand stopper molding portion 24 is provided at a position in front of the traveling direction of the molten metal injected from the gate 22a. It arrange | positions so that the opening of the dam 26 which becomes may face.
Thereby, the molten metal containing inclusions M can be actively guided into the sand stopper molding portion 24 by a natural flow without hindering the flow of the molten metal that has flowed into the cavity space in the pushed water 21c. As a result, the inclusion M can be prevented from flowing into the cavity space side that is the product P1, P2 side, and the occurrence of casting defects can be effectively prevented.

(6)
In the sand mold 20 of the present embodiment, as shown in FIGS. 10A and 10B, the weir 26 that connects the cavity space in the hot water 21 c and the sand stopper molding portion 24 includes a curved portion. It is configured as follows.
Thereby, it can avoid that the product part Pa2 receives a bad influence by the heat | fever etc. from the sand stop shaping | molding part 24 by arrange | positioning the sand stop shaping | molding part 24 and product part Pa2 more closely than necessary.

(7)
In the method for manufacturing the sand mold 20 of the present embodiment, as shown in FIG. 8, a hot water flow simulation is performed on the mold selected in accordance with the shape of the products P1 and P2 to be molded, and the sand stop is based on the result of the simulation. The position of the molding part 24 is determined.
As a result, the inclusion M in the cavity space is concentrated and a portion where a casting defect is likely to occur is specified, and the sand stopper molding portion 24 is provided in the vicinity thereof, thereby concentrating on the specific portion as shown in FIG. Thus, most of the inclusions M that existed in this way can be guided into the sand stop molding part 24. As a result, it is possible to more effectively prevent the occurrence of casting defects by arranging the sand stop molding portion 24 at an optimal position.

[Other Embodiments]
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of invention.
(A)
In the first embodiment, as illustrated in FIG. 1 and the like, an example in which a plurality of sand stop molding portions 14 and 15 are provided around the cavity space S corresponding to the product portion Pa has been described. And in the said Embodiment 2, as shown in FIG. 9 etc., the example which provided the sand stop shaping | molding part 24 around the hot water 21c was demonstrated and demonstrated. However, the present invention is not limited to this.

For example, when there are other parts that may become defect occurrence parts, sand stoppers may be formed around the cavity space corresponding to the product part and around the hot water, respectively.
(B)
In the said Embodiment 1, 2, as shown in FIG.3 and FIG.9, as shown in FIG. 3 and FIG. An example in which weirs 16a, 16b, 26, etc. having a smaller cross-sectional area than the sand stop forming parts 14, 15, 24, etc., are formed as the connecting parts that connect the cavity spaces. However, the present invention is not limited to this.

For example, you may make it connect a sand stop molding part and a cavity, without providing a weir.
However, by connecting both spaces via a weir with a small cross-sectional area, the cross-sectional area can be reduced in order to cause the molten metal that has flowed into the sand stopper to stay and allow foreign matter to stay in the sand stopper space. It is more preferable to connect via a small weir.
(C)
In the said Embodiment 1, 2, as shown in FIG.3 and FIG.9, as for the progress direction through which the molten metal inject | poured into the cavity space S which shape | molds the product P and the hot water 11a-11e flow, and the hot water 22b, An example in which the sand stop molding portions 14, 15, and 24 are provided so that the openings face the positions facing the traveling direction of the molten metal injected into the cavity space in 21c has been described. However, the present invention is not limited to this.

For example, you may make it arrange | position a sand stop shaping | molding part so that the direction of opening may cross | intersect the direction where a molten metal flows.
However, by providing the sand stopper molding part so that the opening is directed in the traveling direction in which the molten metal flows, the molten metal containing foreign substances such as gas and oxide can be efficiently guided into the sand stopper. As in the above embodiment, it is more preferable to arrange a sand-resisting molded part.

(D)
In the first embodiment, an example in which the sand stop forming portions 14 and 15 (sand stops 14a and 15a) are provided at two positions where defects in the product portion Pa are likely to concentrate has been described. On the other hand, in the second embodiment, an example is provided in which one weir 26 is provided that communicates with the sand stopper molding portion 24 not from the vicinity of the product portions Pa1 and Pa2 but from the vicinity of the portion that leads from the runner 22b to the hot water 21c. Explained. However, the present invention is not limited to this.

For example, the number of the sand stop molding portions (sand stops) may be provided at one optimum position or three or more places based on simulation results.
(E)
In the first and second embodiments, as shown in the flowchart of FIG. 8, an example is provided in which the designed mold is simulated, and based on the result, the sand-resin forming portions 14, 15, and 24 are provided in places where casting defects are likely to occur. And explained. However, the present invention is not limited to this.

For example, without performing a simulation, predict a place where a casting defect is likely to occur based on data of a casting defect that has occurred in a previously molded casting, and mold a sand mold provided with a sand-resisting molding part there. May be.
(F)
In the said Embodiment 1, 2, the sand mold was mentioned as an example and demonstrated as a casting mold to which this invention is applied. However, the present invention is not limited to this.

For example, besides the sand mold, the present invention can be applied to other casting molds such as lost wax.
Furthermore, even in the case of a mold, when the cavity side surface has a painted surface or the like, as in the case of a sand mold, the molten metal is filled in the cavity due to the pressure and flow of the molten metal. Since foreign matter may be generated, the present invention can be applied to a mold.

  The casting mold according to the present invention has the effect of removing foreign matters generated inside and outside the cavity space and effectively preventing the occurrence of casting defects due to the inclusion of foreign matters. It is widely applicable to casting molds such as.

The perspective view which shows the structure of the sand type | mold which concerns on one Embodiment of this invention. The enlarged view which shows the sand stop part formed in the circumference | surroundings of the product using the sand mold of FIG. The enlarged view which shows the distribution state of the inclusion in the sand stop part of FIG. The simulation figure which shows the velocity vector in the XY plane of the molten metal by providing the sand-stop part of FIG. The simulation figure which shows the velocity vector in the XZ plane of the molten metal by providing the sand-stop part of FIG. The simulation figure which shows the velocity vector in the YZ plane of the molten metal by providing the sand-stop part of FIG. The schematic diagram which showed the outline of the structure of the sand type | mold which concerns on one Embodiment of this invention. The flowchart which shows the flow at the time of manufacturing the sand mold shown in FIG. The perspective view which shows the distribution state of the inclusion in the sand type | mold which concerns on other embodiment of this invention. (A), (b) is a figure which shows the sand stopper attached to the sand type | mold of FIG. (A), (b) is a perspective view which shows the product formed with the sand mold of FIG. The perspective view which shows the structure of the sand mold used as the comparative example with the sand mold of FIG. (A) is the enlarged view of the A section which shows the condition of the malfunction which generate | occur | produced in the product formed using the sand mold of the comparative example of FIG. (B) is the enlarged view of the B part which shows the condition of a malfunction similarly. The comparison figure which shows the distribution state of the inclusion in the sand mold as a comparative example with the enlarged view of FIG. 3 which shows the distribution state of the inclusion in the sand mold of this invention. The comparison figure which shows the distribution state of the inclusion in the sand type | mold as a comparative example with FIG. 8 which shows the distribution state of the inclusion in the sand type | mold of this invention.

Explanation of symbols

10 Sand mold (casting mold)
11 Product forming parts 11a to 11e Hot water 12 Injecting part 12a Pouring gate 12b Runway 14 Sand stop forming part (foreign matter removing space part)
14a Sand stopper 15 Sand stopper molding part (foreign matter removal space part)
15a Sand stop 16a, 16b Weir (communication part)
20 Sand mold (casting mold)
21 Product forming part 21c Pushing water 22 Injection part 22a Pouring port 22b Runway 24 Sand stop forming part (foreign matter removal space part)
M Inclusion (foreign matter)
P, P1, P2 Product Pa, Pa1, Pa2 Product part S Cavity space (cavity part)

Claims (7)

A cavity that forms a space corresponding to the product part in the mold,
A gate for pouring molten metal into the cavity,
A runner communicating the cavity part and the gate;
A side of the cavity portion in a posture when the molten metal is introduced into the cabty portion and communicated with the cavity portion so as to guide the molten metal flowing into the cavity portion from the runway to the outside of the cavity portion. A foreign matter removal space formed on the side ,
Equipped with a,
The foreign matter removal space has an opening communicating with the cavity at a position facing the traveling direction of the flow of the molten metal injected into the cavity through the runner.
Casting mold. Sand mold,
The casting mold according to claim 1. The foreign matter removal space portion communicates with the cavity portion via a communication portion having a smaller cross-sectional area than the foreign matter removal space portion.
The casting mold according to claim 1 or 2. The foreign matter removal space is formed on a side surface of the cavity in a posture when pouring molten metal into the cavity.
The casting mold according to any one of claims 1 to 3. The foreign matter removal space is formed at a position lower than the connection portion between the cavity and the runner ,
The casting mold according to any one of claims 1 to 4. The communication part that connects the foreign substance removal space part and the cavity part is formed so as to include a curved part.
The casting mold according to any one of claims 1 to 5. It is a manufacturing method of the casting mold according to any one of claims 1 to 6,
A first step of performing a molten metal flow simulation on the molten metal flow for the casting mold;
A second step of determining an arrangement of the foreign matter removal space with respect to the cavity based on the result of the hot water flow simulation;
A casting mold manufacturing method comprising:

Images