JPH0459983B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a water jacket core used in cylinder block casting, and in particular, to a water jacket core used in cylinder block casting, particularly when the bores of cylinder blocks with restricted wall thickness are closely adjacent to each other and the bores are narrow. This invention relates to a water jacket core provided with a cooling water passage.

BACKGROUND ART Conventionally, in the case of cylinder blocks in which bores are adjacent to each other, as shown in FIG. No cooling water passage was provided, and each bore 21 was cooled only from around the bore by cooling water flowing through a water jacket 23 provided around the bore, and the adjacent portion 22 was not cooled.
Later, as a measure to improve engine performance, a cooling water passage was provided in the adjacent portion 22, and the cooling water passage was formed integrally during casting. For this reason, in the first conventional example shown in FIGS. 6 and 7, various ideas have been added to the core of the mold, the main core portion 25 of the water jacket core 24 is
A metal pipe 26 is buried in advance at a position corresponding to the adjacent portion 22.

In the second conventional example shown in FIGS. 8 and 9, the main core portion 25 of the water jacket core 24 is
A hollow flat connecting core 27 made of metal is buried in advance at a position corresponding to the adjacent portion 22, so that the width of the cooling water passage in the adjacent portion 22 is narrowed and the cross-sectional area of the passage is not reduced. This is what I did.
In the third conventional example shown in FIGS. 10 and 11, the main core portion 29 of the water jacket core 28
A gap forming portion 30 is integrally molded into the cast cylinder block, and a cooling water passage is formed in the cast cylinder block.

Problems to be Solved by the Invention The above-mentioned conventional examples 1 and 3 are suitable for casting cylinder blocks in which the distance between the bores is relatively large and the adjacent portions are thick. It is not suitable for cylinder blocks in which the bores are closely adjacent due to restrictions on thickness, and conventional example 2 is used for casting cylinder blocks with thin wall thickness at the adjacent parts, but it is not suitable for casting cylinder blocks with thin hollow tubular bodies made of metal. Connecting core 2
7 is cast as is, so if the metal tubular body is thin, there is a problem that the connecting core 27 may be bent during casting, the hollow portion may be crushed, and the cooling water passage may be blocked. The dot was hot.

Furthermore, since the cooling water passage is provided adjacent to the water jacket of the cast cylinder block, it is difficult to see the passage from the outside, and it is therefore unclear whether the cooling water passage of the set shape is reliably secured. However, there were problems in terms of quality assurance of cast products.

Means for Solving the Problems The present invention provides a water jacket for a cylinder block that is attached to a mold in order to form a cooling water passage around each bore of a cylinder block in which a plurality of bores are formed adjacent to each other by casting. For cylinder blocks, the core consists of a main core part that forms a water jacket part around all the bores, and a connecting core that is connected to the main core part and forms a narrow cooling water passage between adjacent bores. In the water jacket core, the connecting core, which becomes the narrow cooling water passage after casting, is made of a flat hollow metal tube with a thin wall and narrow hollow width that has good fusion with the cylinder block during casting, and is not collapsible. A cylinder block water jacket having a structure in which the inside is filled with good quality zircon sand, both ends are bridged at predetermined positions for forming the main core part, and the main core part and the connecting core are integrated. By providing the core, the above-mentioned problem could be solved.

Function The hollow of the flat metal tube is filled with zircon sand, which is a granular material with good disintegration and high fire resistance, and both ends of the flat metal tube are covered with paper seals. Both ends of the filled and coated metal tube are set in advance in a mold that will form the main core part of a water jacket core for a cylinder block, and the water jacket core mold is filled with shell sand and sintered.
Both ends of the flat metal tube are embedded and integrated into a water jacket core. During the sintering, the paper seal body is substantially burned away.

When a cylinder block is cast using the aforementioned core, a hollow flat metal tube is embedded in the limited wall thickness between adjacent bores of the cylinder block. Since this serves as a cooling water passage, a type of cylinder block with adjacent bores with high cooling efficiency is formed.

The presence of zircon sand, which is a filling refractory with good collapsibility, filled in the tube gives rigidity to the metal tube, which is exposed to high temperatures and pressure from hot water during pouring, and improves the strength of the metal tube. It is now possible to prevent deformation due to thermal strain, and after casting, the refractory filled in the metal tube is allowed to fall cleanly without seizure, resulting in a flat metal tube that remains integrated with the cast cylinder block. The body forms a completely unobstructed hollow, ensuring cooling water passages between the bores.

The core configured as described above can be embedded and integrally cast by the same means not only when casting shells but also when casting cold boxes, hard boxes, warm boxes, etc. other than shells.

Embodiments Hereinafter, the structure of the present invention will be explained with reference to embodiments shown in FIGS. 1 to 4.

As shown in FIG. 13, a water jacket for a cylinder block is attached to a mold in which a cooling water passage 8 is provided in a narrow adjacent portion 7 between the bores 5, 5 of a cylinder block 6 in which bores 5, 5 are formed adjacent to each other. In the core, as shown in Figures 3 and 4,
Water jacket core 3 for cylinder block
However, as shown in FIG.
and a connecting core 1 that is connected to the main core portion 4 and constitutes a narrow cooling water passage 8 provided in an adjacent portion 7 between the bores 5 and 5, as shown in FIGS. 5 and 13. As shown in FIGS. 1 and 2, the connecting core 1, which becomes the narrow cooling water passage 8 after casting, is filled with zircon sand, which is a filling refractory material 2 with good collapsibility, and has both ends made of paper. It consists of a flat, hollow metal tube covered with seals 11, 11.

As the filled refractory 2, a sand-like granular material is used because it has good disintegration properties when removing sand after casting and has a high degree of fire resistance during casting.

For example, after drying zircon sand to a loose sand state and filling it into the connecting core 1 as it is, and covering both ends with paper seals 11, 11, both ends of the connecting core are attached to the main core part 4. After setting, shell sand is blown into the connecting core 1, including around the paper seals 11 at both ends, and fired to form a water jacket core 3, which is then set in a jacket mold 10 as shown in FIG. and used for casting. During the firing, the paper seal body 11 is burnt down and becomes ashes.

As the connecting core 1, for example, as shown in FIG. 1, a thin-walled steel pipe is pressed into a flat hollow plate shape.

Connecting core 1 filled with zircon sand as described above
to prevent the filling from being ejected.
As shown in FIG. 6, it is sealed (sealed) with a paper sealing body 11 such as adhesive paper tape. The filling and sealing connecting core 1 is set in the main core part 4, and the paper sealing body 1 is
The area around the core 1 is filled with shell sand or the like and fired to be integrated as a water jacket core 3.

A test was conducted on a casting core for a cylinder block 6 in which the adjacent portion 7 between the bores 5 and 5 has a thin wall thickness, as shown in FIGS. 5 and 13, in which the minimum thickness of the adjacent portion 7 is 8 mm. . In order to maintain the amount of cooling water that provides an effective cooling effect, the width of the cooling water passage 8 is set to 1 mm. First, for the plate thickness test, the thickness of the iron plate of connecting core 1 was 1 mm,
Test results for 3 types of 0.7mm and 0.5mm 1
With mm and 0.7 mm thickness, poor fusion occurs.
Because it separates from the base material of cast iron, the cooling efficiency as a cooling water passage is poor. The 0.5 mm thick one was completely fused to the base material and had good cooling efficiency.

Next, regarding the prevention of deformation of the connecting core during casting and the collapsibility test of the filled refractory, it was found that if only a hollow connecting core without refractory filling was used, it would deform due to the heat of the hot water during casting. Therefore, in order to prevent deformation, the hollow part of the connecting core is filled with refractory material to add rigidity to the connecting core, and when the shot of the casting is removed from the mold after casting, the refractory material is removed from water. It easily disintegrates within the jacket and needs to be removed. A sand-like filling refractory is best, but tests of silica, ceramic beads, and zircon sand showed that zircon sand was superior in terms of the above-mentioned properties, while other refractories caused seizure during casting and were poor in terms of collapsibility. There was a problem.

The connecting core is plated to prevent rust, but the Ni or Cu plated product had better sand removal during shot polishing, whereas the Sn plated product caused seizure during casting, which was not desirable.

Regarding the leakage prevention test before casting of the refractory filled in the connecting core, it was found that the sealing with paper tape at both ends of the connecting core was good, and the paper seal body 1
1 has a plug-like shape 11 as shown in FIG.
A is not preferable because it may fit into the hollow part of the connecting core 1, and the cap-shaped one shown in FIG. 16 is best.

That is, a 0.5 mm thick iron plate is suitable for the connection core, and has good fusion properties with cast iron without any problem in ensuring a narrow wall thickness in the adjacent portion between the bores.

As a filling refractory, zircon sand does not cause seizure and has good collapsibility.

When plating the hollow inner surface of the connecting core, Ni or Cu plating will improve sand removal.

Effects of the Invention The present invention uses a thin flat hollow metal tube as a connecting core, uses dry bulk zircon sand with high fire resistance as a filling refractory in the tube, and both ends of the flat metal tube Since the cylinder block is sealed with a paper seal body, when a cylinder block is cast using a water jacket core using the above-mentioned connecting core, the paper seal body is completely burned out and the cylinder block is narrowly confined between the bores. A flat hollow metal tube is buried in the adjacent part with a thick wall, which prevents deformation of the tube during casting, and also prevents sand from falling inside the tube after casting, making it completely hollow. It is possible to secure a cooling water passage in the adjacent part of the water jacket between the bores, which is difficult to see from outside the casting, with high reliability. Even with blocks, the cooling effect improves, making it possible to improve engine efficiency.
The quality of the cast cylinder block can be guaranteed, cooling water passages can be installed at the lowest cost, productivity is high, and since the main core is bridged by the connecting core, there is no possibility of deformation of the water jacket core. It has various effects such as being able to prevent.

Note that the paper seals that seal both ends of the connecting core filled with refractories turn into ash due to the heat of the hot water during core firing or casting, so it is difficult to remove sand from the flat metal pipe during sand removal. There is no problem with this.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of an embodiment of a connecting core, Fig. 2 is a perspective view of a connecting core filled with the same refractory material and with a part of the seal body broken, and Fig. 3 is a perspective view of a water jacket core. FIG. 4 is a plan view of the embodiment, FIG. 4 is a sectional view taken along the line in FIG. 3, FIG. Example core plan view, Figure 7 is the 6th
8 is a plan view of the second conventional example core, FIG. 9 is a sectional view taken along the line 8 in FIG. 8, and FIG. 10 is a plan view of the third conventional example core. Fig. 11 is a sectional view taken along the line in Fig. 10, Fig. 12 is a plan view of the core assembly mold, Fig. 13 is a horizontal sectional view of a cast cylinder block using the core of the present invention, and Fig. 14 is a Horizontal sectional view of a conventional cylinder block, No. 15
FIG. 16 is a sectional view of the connecting core with the seal body attached. 1... Connection core, 2... Filled refractory, 3... Water jacket core for cylinder block, 4...
...Main core part, 5...Bore, 6...Cylinder block, 8...Cooling water passage, 9...Water jacket part, 11...Paper seal body.

Claims (1)

[Claims] 1. In order to form cooling water passages around each bore of a cylinder block in which multiple bores are formed adjacent to each other by casting, the water jacket core for the cylinder block attached to the mold has water jackets around all the bores. a main core part forming a butt part;
In a water jacket core for a cylinder block comprising a connecting core that is connected to the main core portion and forms a narrow cooling water passage between adjacent bores, the connecting core that becomes the narrow cooling water passage after casting is: It is made of a flat hollow metal tube with a thin wall and narrow hollow width that has good fusion with the cylinder block during casting.The inside is filled with zircon sand that has good collapsibility, and both ends are used to form the main core part. 1. A water jacket core for a cylinder block, characterized in that the main core portion and the connecting core are integrated with each other by being set on a bridge at a predetermined position.