JPH0211244A - Core used for casting - Google Patents

Abstract

PURPOSE:To reduce limit of hole as cast by using core integratedly assembling thin core body made of artificial sand, which uses alumina series sand sticking resin-made binder as aggregate, and a metallic reinforcing piece having thickness decided related to the thickness of the core body. CONSTITUTION:In the figure, the core 10 applied to a cylinder block core 30 for forming water jacket in the cylinder block for 6-cylinder type diesel engine is shown. The core 10 is used to the hole as cast for forming water passage in cylinder bores 37, 38,.... The core 10 is beforehand formed from each of the core body 11 formed to thin thickness made of alumina series artificial sand and metal having the thickness decided related to the thickness of the core body 11, and manufactured by integratedly assembling the core body and the reinforcing piece 12. The reinforcing piece 12 is manufactured of rolled steel SS40 providing projections 15, 16 at the upper face 13 and projection 17 at the lower face 14 to easily position it in a metallic mold. By this method, the limit of the hole as cast is decided and the hole as cast in the casting having complicate internal space can be made.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a core used in casting suitable for casting out thin-walled areas.

Background Art In recent years, in order to increase the output of automobile engines, changing the bore pitch of the cylinder block changes the length of the crankshaft.
It is also necessary to change the various processing machines that process the inner diameter of the cylinder bore, so without changing the bore pitch of the cylinder block, the cylinder bore formed in the cylinder block is enlarged to increase the output. tends to increase. In addition, in water-cooled engines, there is a further trend toward thinning the cylinder liner to its strength limit to accommodate this. In this way, if the bore diameter of the cylinder block is increased without changing the bore pitch, the distance between the cylinders and the bores will inevitably become narrower. Therefore, the cooling method between the cylinder and bore becomes an important issue during engine operation. That is, when the bore pinch is fixed, the dimensions of the cylinder bore are determined by the dimensions of the cooling water passage between the bores, and the output of the engine is also determined by this.

However, conventionally, the cooling water passage between the cylinder and bore was
Since it was cast with a core made from natural sand, the width of the cast was limited to about 13 fins, and as a result, there was a limit to the increase in output.

Conventionally, when the distance between the cylinders and the bores was to be further narrowed, the cooling water passages were machined into the cylinder block between the cylinders and the bores.

In machining, it is difficult to make holes for long cooling water passages.
Also, this machining process was extremely difficult.

OBJECTS AND PROBLEMS OF THE INVENTION The objects and problems of the present invention are to provide a core for use in casting, which enables the drawing limit to be narrowed beyond the normal limit, and which makes it applicable to the casting of various casting products. It is provided by.

Summary of the structural invention related to the object and problem: Contents of the claimed invention In relation to the above-mentioned object and problem, the core used for casting of this invention is made of alumina-based sand grains to which a resin binder is attached. A core body made of artificial sand to be used as aggregate with a thin wall thickness, and a core body pre-formed from metal with a wall thickness determined in relation to the wall thickness of the core body, and an appropriate position of the core body. and a reinforcing piece that is integrally combined with the core, and narrows the casting limit beyond the usual one, that is, allows the casting limit to be about 2 to 3 mm thick.

Description of Specific Examples Preferred specific examples of the core used for casting according to the present invention will be described below with reference to the drawings.

1 to 3 show the internal space of a cast article (not shown) as a blank for a cylinder block when casting a cylinder block (not shown) for a six-cylinder diesel engine for an automobile; Specific example 1 of a core used in the casting of this invention applied to a cylinder block core 30 forming a so-called water jacket
0.10°10.10.10 is shown.

The cores 10, 10, 10.10.10 were used for casting to form water channels between the cylinder bores of the cylinder block castings, and form part of the cylinder block core 30. Bore 37-38.38-39.39- of the cylinder block core 30 so that
40.4041.41-42 and is integrated into the cylinder block core 30.

The core 10, 10, 10, 10. to has a core body 11 formed with a thin wall thickness from alumina-based artificial sand, and a core body 11 formed in advance from metal with a wall thickness determined in relation to the wall thickness of the core body 11; 11 and reinforcing pieces 12 integrally combined at appropriate positions.

In the cores 10, 10, 10, 10.10, the reinforcing piece 11 constituting the upper end of the cores 10, 10, 10, 10.10 is formed into three thick walls, and The lower end of the core body 11 constituting the lower end of the core body 10, 10.1 (1, 10, 10) is formed to have a wall thickness of 2 fins, and the core body 11 is manufactured to have a tapered longitudinal cross-sectional shape. It is.

The core body 11 is made of artificial sand that has a predetermined particle size distribution and is made of approximately spherical alumina-based sand grains to which a resin binder is attached. Air is blown into a cylinder block core mold (not shown) that has been preheated to 200°C to 300°C and fired together with the reinforcing piece 12, and the core body 11 and reinforcing piece 12 are fired together with the reinforcing piece 12. are fixedly combined with each other and integrated into the cylinder block core.

The reinforcing piece 12 is manufactured from rolled steel material 5340 (Japanese Industrial Standards) in relation to the cylinder block, taking into consideration its fusion with hot water. As can be seen from Figure 3, there are protrusions 15° and 16 on the upper surface 13 at both ends of the piece, and on the lower surface 14 in the center of the piece.
are each provided with a protrusion 17 to facilitate positioning of the cylinder block core within the mold.

In particular, the reinforcing piece 12 is desirably made of a material and shape that is easy to fuse with the hot water in order to maintain reinforcing properties and supporting properties since it is cast, and the thickness of the reinforcing piece 12 is determined taking these into consideration. Determined by

On the other hand, the cylinder block core 30 using the cores 10, 10, 10, 10.10 has the same alumina-based artificial sand as the core body 11 in its cylinder block. The core 1010.10 was fired at the same time as the core 1010.10 by blowing air into the core mold, and the baseboard 3 was placed on the front and rear walls 31.32.
5 and the bosses 36, 36, 36 on one of the side walls 33, 34.
゜36.36 respectively.

The boss 36, 36, 36, 36.36 is the core 1
At the positions corresponding to 0, 10, 10, 10. It provides an air vent when the artificial sand is forced into the mold with air.

Next, we will explain the core making process of molding the cylinder block core 30 which is an integral combination of the above-mentioned cores 10.10.10.10.10. A cylinder block core mold is used, which is divided vertically into a lower mold and a lower mold, and is processed into a hollow or spherical shape, with approximately 30% of mesosure being 0 or less, and approximately 40% of mesosure being 0 to 100. % particle size distribution, and the artificial sand was used as an aggregate made of alumina-based sand grains to which a resin binder was attached in advance.

First, since a release agent has been applied to the upper and lower molds of the mold in advance, five of the reinforcing pieces 12 are set in the lower mold, and the upper mold is placed on the lower mold. Assemble them into the mold.

The mold was then heated to about 300°C. in this case,
Since the cylinder block core 30 is large, the mold was heated to about 300°C, but the heating temperature of the mold is determined depending on the size of the core, binder, etc.
The temperature can be lowered to 00℃.

Once the mold is heated in this manner, the alumina-based artificial sand is forced into the internal space of the mold through the air inlet of the upper mold to fill it.

Then, after 2 to 3 minutes, the alumina-based artificial sand filled in the inner space of the mold loses its binder. The containers are first joined together with the binder.

Thereafter, by removing the upper mold from the lower mold, the core 10, 10, 10, as shown in FIG.
．． A cylinder block core 30 is completed by integrally combining 10.10.

In the above-mentioned core making work, the core 10.10°10.
10.10 was molded simultaneously with the cylinder block core 30, but the cores 10, 10.
10.10.10 are molded in separate molds as shown in FIG. It is also possible to combine it integrally with the child 30.

In this core 10, the core body 11 has a cross-sectional shape B2x
HxB, = 3x20x2.5 (unit: angle), and if reinforcing pieces were not used, they would have been easily damaged during the casting process, but by using the reinforcing pieces 12, casting was made easier. It's now possible.

Furthermore, the cylinder block core 30 described above has a fifth
As shown in the figure, the core 10. t.

If the holes 20 are made in the core body 11 of 10.10.10, it becomes possible to carry out casting, so-called multi-stage casting, in which the shape of the water channel in the cylinder/block casting is changed as appropriate. And like this, the core 10,1
If 0.10, 10.10 is punched and there is a part where the waterway is divided into upper and lower parts, the strength of the cylinder block increases between the cylinder bores.

Also, the smaller the particle size of the alumina-based artificial sand, the narrower the casting limit of the core 10, and the cylinder block eliminates troublesome drilling operations.

Furthermore, in the core 10 described above, the reinforcing piece 12 was described as being integrally combined with one end of the core body 11, but depending on the cast shape, the reinforcing piece 12 may be adjusted as appropriate. It is manufactured in the shape of , and is integrally combined with the core body as appropriate.

Furthermore, the core 10 described above was embodied in the casting of a water channel in a cylinder block, but the core 10 can be modified in shape to suitably be used in a cylinder head, a disc brake disc brake disc of an automobile, etc. , can be widely applied to torque converter parts, etc.

Conveniences and Benefits of the Invention As can be understood from the above, compared to cores used in casting that have already been proposed and used,
The core used in the casting of the invention consists of a thin core body made of artificial sand whose aggregate is alumina-based sand particles to which a resin binder is attached; The core used in the casting of the present invention is composed of reinforcing pieces that are preformed from metal to a related thickness and are integrally assembled at appropriate positions on the core body. In this case, the casting limit is narrowed beyond the normal one, specifically to a wall thickness of 2 to 3 mm, and various castings, especially the complex internal ring pores are enlarged and the cylinder・It is possible to increase the engine output without changing the volume of the block, and at the same time, a water channel is formed by casting between the cylinder bores of the cylinder block, which is narrowed by the large cylinder bore. For the water channels, drilling is saved and is thus very useful for castings with complex interior spaces.

Regarding the specific examples of the invention, from the specific examples of the invention described with reference to the drawings, various design modifications will be apparent to those who have ordinary knowledge in the technical field to which this invention pertains. Further, the contents of this invention are essential to the establishment of the invention for accomplishing the task of the invention, and are derived from the technical essence of the invention which is the nature of the invention. and can be easily replaced with a form that is objectively recognized as incorporating it.

[Brief explanation of the drawing]

Figure 1 shows the cylinder of an automobile diesel engine.
FIG. 2 is a perspective view of a concrete example of the core used in the casting of the present invention, which is integrally combined with the cylinder block core when casting the block, with the lower side facing up. 3 is a perspective view of the reinforcing piece used in the core shown in FIG. 1, and FIG. 4 is a cross-sectional view taken along line 2-2, and FIG. FIG. 5 is a perspective view of the core shown in FIG. 5, and a sectional view corresponding to FIG. 2 of the core used in the casting of the present invention, in which a hole is drilled in the core body. 11... Core body, 12... Reinforcement piece. Tail 3 figure

Claims (1)

[Claims] (1) A core body formed with a thin wall thickness from artificial sand whose aggregate is alumina-based sand grains to which a resin binder is attached, and a wall thickness determined in relation to the wall thickness of the core body. A core used in casting that includes reinforcing pieces that are preformed from metal and are integrally assembled at appropriate positions on the core body.