JPH07256393A - Sand mold for casting and method for molding sand mold - Google Patents

Abstract

PURPOSE:To reduce defects due to the insufficient filling of the molten metal by suppressing the run-out form the joint of sand cores in a sand mold for casting consisting of a sand mold and a plurality of sand cores which are continuously arranged therein. CONSTITUTION:A plurality of cores (a core print part is indicated by the number 7) are continuously arranged in a main mold 1 symmetrically to the center line and a recessed part is provided at the part to be held by end parts 10 of the core print parts. A pressing claw 14 is inserted inside the recessed part, and a wedge is inserted to press the claw toward the respective end parts 10 from the inside of the recessed part in the horizontal direction, and the sand of the main mold 1 is pressed against the joint of the end parts of the sand cores. The main mold 1 is brought into close contact with the end part 10 of the core to block the joint of the cores, and the run-out from the end parts 10 can be suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sand mold for casting, which comprises a sand mold and a plurality of sand cores connected to the sand mold, and a method for molding the sand mold for casting.

[0002]

2. Description of the Related Art A sand mold for casting, in which a plurality of sand cores are connected and arranged in a main mold composed of sand molds, for example, a combination of cores is one.
In the sand mold of the bore 1 core type cylinder block, as shown in FIGS. 5 and 6, a plurality of sand cores 2 (2a to 2d) are connected to each other at predetermined positions in the main mold (lower mold) 1. Has been done. Inside the core 2, there is a hole 3 for weight reduction.
Is formed, and as shown in FIG. 7, the central core 2b,
A runner 4 communicating with a runner of an upper die (not shown) is formed on the side surface of the skirting portion on the oil pan side of 2c so as to guide the hot water to the bottom of the mold cavity. In FIG. 5, 5
Is the water jacket core.

The cores 2 are assembled by arranging the skirting boards 6, 7 formed at both ends thereof at predetermined positions of the lower mold 1 so as to be in close contact with each other, but between the lower mold 1 and the core 2. Since a clearance for assembling is provided in advance, a gap may be formed at the joint 8 (FIG. 6) of each core 2 at this time, and the hot water pressure applied at the time of casting may cause leakage of hot water from this gap. For this reason, after assembling the core 2 into the lower mold 1, the sand puncher 9 is driven into the vicinity of the skirting boards 6, 7 of the lower mold 1 from diagonally above both sides, and each core 2 is left and right with the sand of the lower mold 1. They are pressed against each other so that they are in close contact with each other to close the gap of the seam 8.

However, when the sand puncher 9 is driven in, the cores 2a, 2d at the left and right ends (on the front and rear sides of the cylinder block) can be moved relatively easily to close the gap, but the core 2b in the central portion can be closed. 2c, the driving force is not sufficiently transmitted and the effect of filling the gap of the joint is small. In particular, as the number of cores to be connected and arranged increases, the effect of filling the gap becomes smaller. It flows out and flows into the hole 3 of the core through the gap between the end face 10 and the lower die 1 (clearance for core assembly), so that there is a problem that the molten metal becomes insufficient and an unfilled part is generated in the casting part.
On the other hand, when the punching force of the sand puncher 9 is increased in order to strongly press the core 2, the lower mold 1 is deformed and the core 2 is damaged, and the movable rate of the molding line is lowered.

In Japanese Patent Publication No. 5-185181, a core is formed by forming an adhesive injection through hole that linearly penetrates a plurality of cores and integrally connecting the cores with an adhesive. It is described that a gap is prevented from occurring between them, but this increases the number of steps for molding the core, resulting in a loss of time until the adhesive solidifies, and the adhesive is cast. Another problem arises, such as becoming a source of gas generation.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and in a sand mold for casting, which comprises a sand mold and a plurality of sand cores connected to the sand mold, With the aim of suppressing hot water leakage with simple means,
Another object is to reduce defective defects caused by insufficient filling of hot water.

[0007]

DISCLOSURE OF THE INVENTION The present invention relates to a method for molding a sand mold for casting in which a plurality of sand cores are connected and arranged in a main mold composed of sand molds, and the end seam of the plurality of sand cores is The main mold is characterized by pressing sand at a location facing the end to bring the main mold and the end into close contact, and if necessary, by means of the sand puncher, etc. After applying a pressing force through the sand of the mold in the connecting direction, press the sand at the location facing the end of the main mold against the end joints of the plurality of sand cores, and press the main mold and the end. It is characterized by closely contacting. In the above method, the sand at the location facing the end of the main mold is pressed against the end seams of the plurality of sand cores, and when the main mold and the end are brought into close contact, the end of the main mold is It is preferable to provide a recess near the portion facing the section and press from the inside of the recess toward the end.

The present invention also relates to a sand mold for casting suitable for carrying out the above method, which comprises a main mold made of a sand mold and a plurality of sand cores connected to each other in the main mold. The sand mold for casting is characterized in that a recess is provided in the vicinity of a portion facing the end joint of the sand core of the mold.

[0009]

According to the present invention, the sand core is pressed against the end joints of the plurality of sand cores at the location facing the end of the main mold to bring the sand of the main mold into close contact with the end. It closes the gap between the end joints of. Even if hot water leaks in the gaps between the seams of the sand core, the seams are blocked by the sand of the main mold at the end portion 10 so that the water does not flow out any more. In gravity casting using the bottom pouring method, the pressure of the molten metal on the upper mold side is lower than that on the lower mold side, so there is little possibility of molten metal leaking from the upper mold side, and only the end joints on the lower mold side are closed. It is possible to achieve the intended purpose with.

When pressing the sand at the location facing the end of the main mold against the end joints of the plurality of sand cores,
When a concave portion is provided in the vicinity of a portion facing the end portion of the main mold and is pressed from the inside of the concave portion toward the end portion, the joint of the end portions is formed without applying an excessive force to the main mold and the core. It can be closed without damaging the sand mold.

[0011]

EXAMPLE A sand mold for casting according to this example shown in FIGS. 1 and 2 is a 1 bore 1 core type cylinder block.
Regarding the sand casting mold for individual casting, as compared with the conventional example shown in FIGS. 5 to 7, the end face 10 of the oil pan side skirting part 7 of the core 2 symmetrically arranged in the lower mold 1 is faced. A point where a recess 11 having a depth similar to that of the skirting board of the lower die is provided in the vicinity of the portion where the dies are formed, that is, in a portion of the lower die 1 sandwiched by the ends 10 of the left and right oil pan side skirting pieces 7. The sand mold for casting is the same in other respects, such as a plurality of sand cores 2 connected to each other in the lower mold 1 and a water jacket core 5 further arranged. 1 and 2, the same parts as those in the conventional example shown in FIGS. 5 to 7 are denoted by the same reference numerals.

In this sand casting mold, the procedure for filling the gap between the cores 2 or the gap between the end 10 of the core 2 and the lower mold 1 will be described. First, the phantom line of the lower mold 1 is shown. A sand puncher similar to that described in the conventional example is driven into the position 12 (near the skirting boards 6 and 7 at both ends of the core 2) from diagonally above both sides to close the gap between the cores 2. next,
A pair of pressing claws 14 which can be opened and closed centering around the fulcrum 13 are inserted into the recess 11 from above (see FIG. 3), and both pressing claws 14 are inserted.
Insert the wedge 15 between and open it to the left and right (Fig. 4
reference). Before opening the pressing claw 14, there is a slight gap between the end 10 of the skirting part 7 and the lower mold 1 as described in the conventional example. The sand at the location facing the end 10 is pressed horizontally against the end 10 to close this gap. In addition, 16 is a wedge 1
The roller 17 engaging with 5 and 17 are cracks in the sand of the lower mold 1.

In this embodiment, a sand puncher is driven in to close the gap between the cores 2 and the pressing claws 14 are opened in the recesses 11 so that the lower end portion 10 of the core 2 is molded. Since the sand of No. 1 is pressed to close the joint at the end portion 10, even if the gap between the joints of the cores 2 is not sufficiently blocked and hot water leaks here,
It is possible to reliably stop the flow of molten metal at the end portion 10 and suppress defective defects due to insufficient filling of the molten metal.

[0014]

EFFECTS OF THE INVENTION According to the present invention, in a casting sand mold consisting of a sand mold main mold and a plurality of sand cores connected to each other, leakage of water is suppressed, and furthermore, insufficient filling of hot water is caused. It is possible to reduce defective defects caused by

[Brief description of drawings]

FIG. 1 is a plan view of a lower mold of an embodiment and a core assembled in the lower mold.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a diagram for explaining the action of a pressing claw.

FIG. 4 is a diagram for explaining the action of the pressing claws.

FIG. 5 is a front sectional view of a lower mold of a conventional example and a core assembled in the lower mold.

FIG. 6 is a view taken along the line BB of FIG.

FIG. 7 is a view on arrow CC of FIG.

[Explanation of symbols]

 1 Lower mold 2 Core 3 Hole formed in the core 4 Runway 6, 7 Core skirting part 8 Joints of cores 10 End of the oil pan side skirting part of the core 11 In the lower mold The recess 14 provided

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hisawa Oshima 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Motor Corporation

Claims (4)

[Claims] 1. A method for making a sand mold for casting, in which a plurality of sand cores are connected and arranged in a main mold made of sand molds, wherein the end portions of the plurality of sand cores face the end portions of the main mold. A method for molding a sand mold for casting, characterized in that the sand at a point to be pressed is pressed to bring the main mold and the end portion into close contact with each other. 2. A molding method of a sand mold for casting in which a plurality of sand cores are connected and arranged in a main mold made of a sand mold, wherein a pressing force is applied to the plurality of sand cores in the connecting direction via the sand of the main mold. A sand mold for casting, characterized in that, after the addition, the sand at the position facing the end of the main mold is pressed against the end joints of the plurality of sand cores to bring the main mold and the end into close contact with each other. Molding method. 3. The casting according to claim 1, wherein a recess is provided in the vicinity of a portion of the main mold facing the end, and the recess is pressed from the inside of the recess toward the end. Sand mold making method. 4. A main mold made of a sand mold, and a plurality of sand cores connected to each other in the main mold, wherein a concave portion is provided in the vicinity of a portion facing the end seam of the sand core of the main mold. A sand mold for casting, which is provided.