JP3344818B2 - Sand mold for casting and method of molding sand mold - Google Patents

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 comprising a sand mold and a plurality of sand cores arranged in the sand mold, and a method for molding a 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 in a main mold made of a sand mold, 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 (2 a to 2 d) are connected to each other at predetermined positions in a main mold (lower mold) 1. Have been. Hole 3 for weight reduction inside core 2
Are formed, and as shown in FIG.
A runner 4 communicating with the runner of the upper mold (not shown) is formed on the side surface of the skirting part on the oil pan side of 2c, and the hot water is guided to the bottom of the mold cavity. In FIG. 5, 5
Is a water jacket core.

Each core 2 is assembled by arranging skirting portions 6, 7 formed at both ends thereof at predetermined positions of the lower die 1 so as to be in close contact with each other. 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 hot water may be leaked from the gap due to the hot water pressure applied during casting. For this reason, after assembling the core 2 into the lower mold 1, the sand punchers 9 are driven into the vicinity of the baseboard portions 6 and 7 of the lower mold 1 from diagonally upper sides, and each core 2 is left and right with the sand of the lower mold 1. From each other to make them close to each other so as to close the gap of the joint 8.

However, by driving in the sand puncher 9, the cores 2a and 2d (front and rear sides of the cylinder block) on both the left and right sides can relatively easily move and close the gap. 2c, the driving force is not sufficiently transmitted, and the effect of narrowing the gap between the joints is small. In particular, as the number of cores arranged in series increases, the effect of filling the gap decreases, and when the gap is not filled sufficiently, hot water leaks through the gap, and hot water flows from the end face 10 of the oil pan side skirting part 7. It flows out and flows into the hole 3 of the core through the gap (clearance for assembling the core) between the end face 10 and the lower mold 1, so that there is a problem that hot water is insufficient and an unfilled portion is generated in the casting.
On the other hand, if the driving force of the sand puncher 9 is increased in order to strongly press the core 2, there is a problem that the lower die 1 is deformed and the core 2 is damaged, and the movability of the molding line is reduced.

In Japanese Patent Publication No. 5-185181, a through hole for injecting an adhesive is provided which penetrates a plurality of cores linearly, and the cores are integrally connected by an adhesive. Although it is described that a gap is prevented from occurring between the cores, the number of man-hours for molding the core increases, a time loss occurs until the adhesive solidifies, and the adhesive is cast. Another problem arises, such as being a source of gas in time.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and is directed to a sand mold for casting comprising a sand mold and a plurality of sand cores connected to the sand mold. The purpose is to suppress hot water leakage by simple means,
Another object is to reduce defective defects caused by insufficient filling of hot water.

[0007]

SUMMARY 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 made of a sand mold. To do
A recess is provided in the vicinity of a place, and the inside of the recess is
Characterized in that by pressing, pressing the sand portion facing said end portion of the main mold to the end seam of a plurality of sand core, to close the main type as the <br/> end I And, if necessary, after applying a pressing force to the sand core in the connecting direction through the main mold sand by means of the sand puncher or the like ,
Providing a recess near the end facing the end of the sand core,
Pressing from the inside of the recess toward the end, the sand at the location facing the end of the main mold is pressed against the end joint of the plurality of sand cores, and the main mold and the end are brought into close contact with each other. It is characterized by making it.

[0008] The present invention also relates to a casting sand mold suitable for carrying out the above method, comprising a main mold made of a sand mold and a plurality of sand cores connected in the main mold. A casting sand mold characterized in that a concave portion is provided in the vicinity of a portion facing an end joint of a sand core of the mold.

[0009]

According to the present invention, the sand core by closely pressing the sand portion facing said end portion of the main mold to the end seam of a plurality of sand core, the main type of sand to the end To close the gap at the end joint. Even if hot water leaks into the gap between the joints of the sand core, since the joint is closed at the end portion 10 by the main type sand, there is no further flow out. In addition, in the gravity casting of the lower pouring method, since the pressure of the hot water is lower on the upper mold side than on the lower mold side, the possibility of hot water leakage from the upper mold side is low, and only the end joint of the lower mold side is closed. It is possible to achieve the intended purpose.

[0010] A main mold is used for the end joint of a plurality of sand cores.
When pressing the sand portion facing said end portion, prior to the main mold
A concave portion is provided in the vicinity of the portion facing the above-mentioned end portion, and by pressing from the inside of the concave portion toward the above-mentioned end portion, the seam of the above-mentioned end portion is closed without applying excessive force to the main mold and the core. And there is no breakage of the sand mold.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A casting sand mold according to the present embodiment shown in FIGS.
Regarding the sand casting mold for individual casting, as compared with the conventional example shown in FIGS. 5 to 7, the sand mold facing the end 10 of the oil pan side skirting portion 7 of the core 2 symmetrically arranged in the lower mold 1. In the vicinity of the place where the lower die 1 is located, that is, in the portion of the lower die 1 sandwiched between the ends 10 of the left and right oil pan side skirting portions 7, a recess 11 having the same depth as the lower die skirting portion is provided. In other respects, the same sand casting mold is used, for example, a plurality of sand cores 2 are connected and arranged in a lower mold 1, and a water jacket core 5 is further arranged. 1 and 2, the same parts as those of the conventional example shown in FIGS. 5 to 7 are denoted by the same reference numerals.

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 in this casting sand mold will be described. A sand puncher similar to that described in the conventional example is driven into the position 12 (near the skirting portions 6 and 7 at both ends of the core 2) from diagonally above both sides, and the gap between the cores 2 is narrowed. next,
A pair of pressing claws 14 that can be freely opened and closed around the fulcrum 13 is inserted into the recess 11 from above (see FIG. 3),
Insert wedge 15 in between and open it to the left and right (Fig. 4
reference). Before the pressing claw 14 is opened, there is a slight gap between the end 10 of the baseboard portion 7 and the lower mold 1 as described in the conventional example. The sand facing the end 10 is pressed horizontally against the end 10 to close the gap. 16 is wedge 1
The roller 17 engaging with 5 is a crack in the sand of the lower mold 1.

In this embodiment, the gap between the joints of the cores 2 is filled by driving a sand puncher, and the pressing claw 14 is opened in the concave portion 11 so that the lower die 10 is attached to the end 10 of the core 2. 1 is pressed against the sand to close the joint at the end portion 10, so even if the gap between the joints between the cores 2 is not sufficiently clogged and hot water leaks here,
The flow of the molten metal is reliably stopped at the end portion 10, and defective defects due to insufficient filling of the molten metal can be suppressed.

[0014]

According to the present invention, in a casting sand mold composed of a main mold made of a sand mold and a plurality of sand cores connected to the main mold, it is possible to suppress the leakage of hot water, and furthermore, the insufficient filling of the hot water. Defective defects caused by the above can be reduced.

[Brief description of the drawings]

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

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

FIG. 3 is a diagram illustrating the operation of a pressing claw.

FIG. 4 is a view for explaining the function of the pressing claw.

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

FIG. 6 is a view taken in the direction of arrows BB in FIG. 5;

7 is a view taken in the direction of the arrows CC in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower mold 2 Core 3 Hole formed in core 4 Runner 6 and 7 Core skirting part 8 Joint of cores 10 End of oil pan side skirting part of core 11 Lower part Provided recess 14 Pressing claw

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hisakazu Oshima 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Co., Ltd. (56) References Japanese Utility Model 1977-160849 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B22C 9/02

Claims (3)

(57) [Claims] 1. A method for molding 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.
A recess is provided in the vicinity of the location facing the end of the sand core,
Is pressed toward the end from the recess inside, pressing the sand portion facing said end portion of the main mold to the end seam of a plurality of sand core, to close the main type as said end portion A method for molding a sand mold for casting, characterized in that: 2. A method of molding 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. After the addition, the main mold is recessed in the vicinity of the location facing the end of the sand core.
And pressing the inner side of the recess toward the end.
Te, pressing the sand portion facing said end portion of the main mold to the end seam of a plurality of sand cores, the main type as the molding of the casting sand molds, characterized in that to close the said end portion Method. 3. A main mold made of a sand mold and a plurality of sand cores connected in the main mold, and a concave portion is formed near a portion facing an end joint of the sand core of the main mold. A sand mold for casting, which is provided.