JPH03282Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is used in combination molds that combine various cores, such as automobile cylinder blocks, by forming molds on the mating surfaces of cores or between cores and outer cores. This invention relates to a combination mold that prevents molten metal from leaking from the surface mating with the mold.

BACKGROUND ART Conventionally, a combination mold in which two or more cores are combined has a mating part in which adjacent surfaces of the ends of the core are brought into contact with each other, and an outer mold is placed in contact with this mating part. has been done. An example of this conventional combination mold, which is a mold for casting a V-shaped cylinder block, will be explained with reference to FIG.

Water jacket cores 2, 2 having a larger diameter than the cylindrical portion are loosely fitted into a cylindrical portion provided at the upper end of the crankcase core 1. Slab cores 3, 3 are connected to the upper end of 2. The cross section of the gap formed between the slab cores 3 is approximately V.
An upper core core 4 of the mold is arranged, and the upper end side surface 4a of the upper core core 4 and the inner side surface 3a of the slab core 3 are brought into contact with each other so as to face each other to form a mating part. has been done. A mold is formed by combining each of these cores and the outer mold 5 so that the mating portions are brought into contact with the inner surface of the outer mold, and this mold is used for casting molten metal.

Problems to be solved by the invention However, it is necessary to form some gaps between the contact surfaces of the mating parts of the core, that is, the mating surfaces, for mold assembly, and even if no gaps are formed, this There is a problem in that hot water often leaks from the joints. If molten metal leaks from the mating surfaces between the cores or the mating surfaces between the core and the outer mold and goes around to the back side of the core, a part of the cast product may become thin. This can cause product defects, and the solidified lumps formed on the back of the core due to hot water leakage can cause problems in subsequent processes, such as damage to the core and scratches on the product surface when demolding. There is a risk. In addition, in the case of such chronic leakage, it is necessary to constantly inject extra molten metal into the mold to cope with the leakage, which reduces the casting yield and ultimately increases the manufacturing cost of the cast product. becomes.

On the other hand, it is also conceivable to increase the area of the mating surfaces by enlarging the upper end of the core. However, according to this method, the core itself becomes larger and its weight also increases, which makes handling cumbersome and may impair work efficiency.

The basic purpose of this invention is to solve the above problems, and to provide a combination mold that effectively prevents molten metal from leaking from the mating surfaces with a simple structure without increasing the weight of the core. It is something to do.

Means for Solving the Problems In other words, this invention provides a combination mold in which two or more cores are combined and the joints of the cores are in contact with the outer mold. At the end of one core in the mating part,
It is characterized in that an extension part is formed to cover the surface of the end of the other core on the outer mold side, and the tip end surface of this extension part is brought into contact with the inner surface of the outer mold.

Note that it is preferable that the combination mold is a sand mold, and that a convex portion is formed on the inner surface of the outer mold that abuts the tip end surface of the extending portion.

Function According to this invention, the extending portion formed at the end of one core in the joint portion of the cores covers the surface of the end of the other core on the outer mold side, so that In addition to the opposing mating surfaces, the area of the mating surfaces is increased.
Furthermore, the tip end surface of the extending portion and the inner surface of the outer mold are brought into contact with each other, thereby increasing the leakage prevention effect. In addition, by making this abutting surface nearly parallel to the parting surface of the outer mold, it is possible to make close contact on the abutting surface, and the opposing abutting surface of the mating part between the cores To ensure prevention of leakage of hot water even when it is necessary to form a gap between.

In addition, if the outer mold is made of a sand mold and a convex part is formed on the inner surface of the outer mold that comes into contact with the tip end surface of the extension part, this convex part will be caused by the end face of the extension part when assembling the core. Since it is compressed and expanded, the tip surface and the inner surface of the outer mold are uniformly and tightly abutted.

Embodiment An embodiment in which this invention is applied to a V-shaped cylinder block will be described below with reference to the accompanying drawings.

Crankcase core 1 as shown in Figure 1
A pair of cylindrical portions are provided at the upper end, and water jacket cores 2, 2 having a larger diameter than the cylindrical portions are loosely fitted into the cylindrical portions,
Slab cores 3, 3 are connected to the upper ends of the water jacket cores 2, 2. An upper core core 6 having a substantially V-shaped cross section is disposed in the gap formed between the slab cores 3 . This upper core core 6
The side surface 6a at the upper end of is the inner side surface 3 of the slab core.
a, and an extending portion 7 is formed at the upper end thereof so as to protrude outward. This extending portion 7 is a surface 3 on the outer mold side of the slab core 3.
The lower surface 7a of the extending portion 7 and the surface 3
b are brought into contact with each other. Furthermore, the tip end surface 7b of this extending portion 7 is shaped to follow the inner surface 5a of the outer molds 5, 5. When a mold is formed by combining these cores and the outer molds 5, 5, the side surfaces 6a and 3a, the lower surface 7a and the surface 3b, the tip surface 7b and the inner surface 5a are brought into contact. Even when it is necessary to form a gap between the side surface 6a and the side surface 3a for mold assembly, this contact is possible because the tip surface 7b of the extension part 7 and the inner surface 5a of the outer mold 5 are brought into contact with each other. The contact surface is the parting surface 5b of the outer mold 5, 5
As a result, the distal end surface 7b and the inner surface 5a can be brought into close contact with each other, thereby ensuring prevention of hot water leakage.

Next, the operation of this embodiment will be explained.
The cast molten metal firstly forms the side surface 6a and the side surface 3a.
The mating surface prevents hot water from leaking. Even if hot water leaks from this mating surface, the leakage will be reliably prevented by the second and third mating surfaces, which are the abutting surfaces between the lower surface 7a and the surface 3b, and the abutting surfaces between the tip surface 7b and the inner surface 5a. Ru. Even if a gap is formed as necessary between the mating surfaces of the side surface 6a and the side surface 3a, the leakage prevention effect is not impaired because the second and third mating surfaces are in close contact with each other.

FIG. 3 is an enlarged view of the main part of another embodiment, in which a convex portion 8 is formed on the inner surface 8a that comes into contact with the distal end surface 7b of the extending portion 7.
c. When assembling the combination cores of this embodiment, the convex portion 8c comes into contact with the tip surface 7b and is crushed, and spreads uniformly to form a flat layer 8d, so that the tip surface 7b and the outer mold 8 are The contact with the inner surface 8a is made more tightly.

Effects of the Device As explained above, according to this device, one of the cores in the mating portion is shaped to abut against the side and outer surface of the other core, and an outer mold is formed on the end surface of the one core. I made it so that the inner surfaces were in contact with each other, so
To reliably prevent molten metal from leaking with a simple structure without increasing the weight of the core.

In addition, if the outer mold is made of a sand mold and a convex portion is formed on the inner surface of the outer mold that contacts the end surface of one of the cores, the contact between the mating surfaces will be tighter, and the leakage prevention effect can be further enhanced. .

[Brief explanation of drawings]

Fig. 1 is a sectional view of one embodiment of this invention, Fig. 2 is an enlarged sectional view of the part shown in Fig. 1, and Fig. 3 is an enlarged view of main parts of another embodiment. B is a cross-sectional view of the state before the cores are combined, and FIG. 4 is a cross-sectional view of a conventional combination mold. 3a... Side surface, 3b... Outer mold side surface, 6... Upper core core, 6a... Upper core core side surface, 7... Extension part,
7b...extending portion tip surface, 5a, 8a...outer mold inner surface, 8c...convex portion.

Claims (1)

[Claims for Utility Model Registration] (1) In a combination mold in which two or more cores are combined and the joints of these cores are configured so as to be in contact with the outer mold, the joints of the cores An extension part is formed at the end of one of the cores to cover the surface of the end of the other core on the outer mold side, and the tip surface of this extension part is brought into contact with the inner surface of the outer mold. A combination mold characterized by: (2) The assembly according to claim 1, wherein the outer mold is made of a sand mold, and a convex portion is formed on the inner surface of the outer mold that comes into contact with the tip end surface of the extending portion. Matching mold.