JPH10193077A - Core for casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a core for casting which can simply reinforce a bore by coating slurry mixing complex grain composed of main grain of hard grain and auxiliary grains having good matching with molten iron into water glass on the surface of the casting core inserted in a mold and forming a bore of a cylinder, etc. SOLUTION: The reinforcing layer 11 is coated at the upper part and the lower part on the outer peripheral surface of the core 10 for forming the bore of the cylinder block. The reinforcing layer 11 is coated on the core 10 and dried with mixed material of single or various kinds of the complex grains 12 which are made to capsule with the auxiliary grains 14 of iron powder, cast iron powder, aluminum powder in the case of e.g. the cast iron of the same base metal as the cylinder block on the outer periphery of the main grain 13 using powder having <=10μm of the hard grain, e.g. alumina, WC, SiC, etc., as nucleus and further, is made to slurry with the water glass. The core for casting forming the reinforced layer 11 is set in a molding flask and the molten metal of the cast iron, etc., is poured and case. By this constitution, the reinforced layer on the bore surface can simply be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting core used for casting a cylinder block or the like.

[0002]

2. Description of the Related Art Cylinder blocks have become liner-less in order to make engines lighter and more compact.
A method is employed in which a wear-resistant material is cast into the piston sliding surface of the cylinder.

[0003] This method uses a cast iron material for an aluminum block,
Cast iron blocks are made of a special alloy cast iron material and formed into a cylinder, and this cylinder is cast as a liner at the same time as casting.However, various surface coatings and preheating are required as a pretreatment before casting, which increases costs. And quality instability.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. 4-66259, a foam containing phosphorus powder is arranged around a core forming a bore, and this is inserted into a mold and molten metal is poured into the cylinder to form a cylinder bore. A production method of casting a cylinder block having a surface made of high-phosphorus cast iron has been proposed.

[0005]

However, in this manufacturing method, an iron-based cover is provided to distinguish the modified portion (reinforced portion) from other portions, and the phosphorus powder flows and mixes throughout the molten metal. And it is necessary to provide a plurality of small holes in the iron-based cover for introducing the molten metal to the core side, resulting in a problem that the production cost is increased.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a casting core capable of easily reinforcing a bore of a cylinder or the like.

[0007]

Means for Solving the Problems In order to achieve the above object, the present invention is directed to a casting core which is inserted into a mold to form a bore of a cylinder or the like. This is a casting core in which composite particles composed of molten metal and familiar particles are mixed with water glass to form a slurry, and this slurry is applied to the surface of the core.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a casting core according to the present invention, in which a reinforcing layer 11 is applied to the upper and lower portions of the outer peripheral surface of a core 10 forming a bore of a cylinder block.

The reinforcing layer 11 is formed on the outer periphery of a base particle 13 having hard particles, such as alumina, WC, SiC or the like, having a core of 10 μm or less as a core, and is similar to a cylinder block (for example, in the case of cast iron, Child particles 1 of cast iron powder, aluminum powder)
4 are encapsulated to form composite particles 12, and the composite particles 1
A slurry of water alone or a mixture of various composite particles 12 alone is coated on a core 10 and then dried to form a mixture.

A casting core 20 in which a reinforcing layer 11 is formed on the core 10 is set in a mold 21 as shown in FIG.
By pouring molten metal such as cast iron into the formwork 21, the cylinder block 22 shown in FIG. 2 can be cast.

In FIG. 2, reference numeral 23 denotes a water jacket, 24 denotes a cylinder bore cast by the casting core 20 of the present invention, and a reinforcing layer 25 corresponding to a conventional cylinder liner is formed on the inner surface of the cylinder at the same time as casting of cast iron. Can be formed.

That is, when the molten metal is poured into the mold,
The water glass of the reinforcing layer 11 is melted by the heat of the molten metal (1800 ° K or more), and the surface of the encapsulated composite particles 12 is a component of the same type as the molten metal. Is impregnated, has good familiarity and wettability,
The reinforcing layer 25 is formed on the cylinder bore 24 side in such a manner that the child particles 14 are melted and the base particles 13 are dispersed.

In this case, by setting the size of the base particles 13 to 10 μm or less, deterioration of workability due to addition of hard particles can be greatly reduced. In addition, Vf can be freely set by adding the same particles as the child particles 14 in accordance with the ratio (Vf) of the base particles 12 necessary for producing a slurry to be applied.

A quenching device after casting, a pretreatment unit for casting (for example, Al diping in a melt coating method), a preheating furnace, and the like are not required, and the cost is reduced.

Further, in the case of composite particles 12 using aluminum powder as child particles 14, the amount of Al added is preferably 4% or less of other added particles (base particles 13 and child particles 14). Although it is effective to promote the graphitization of carbon in cast iron, adding 4% or more does not change the effect, and conversely lowers the strength.
% Or less is good.

[0017]

In summary, according to the present invention, by forming a reinforcing material layer on a core and casting a cylinder block or the like,
It is possible to easily form a reinforcing layer on the bore surface.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is a plan sectional view of a cylinder block cast with the casting core of the present invention.

FIG. 3 is a sectional view showing a state at the time of casting in FIG. 2;

[Description of Signs] 10 core 11 reinforcing layer 12 composite particle 13 base particle 14 child particle

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yuichiro Hara 8 Dosa, Fujisawa-shi, Kanagawa Prefecture Isuzu Central Research Institute Co., Ltd. (72) Inventor Asao Koike 8 Dosa, Fujisawa-shi, Kanagawa Isuzu Central Research Inc. In-house (72) Inventor Masato Motoyoshi 8 Tsurana, Fujisawa, Kanagawa Prefecture Isuzu Central Research Institute Co., Ltd.

Claims (1)

[Claims] 1. In a casting core which is inserted into a mold to form a bore of a cylinder or the like, a composite particle composed of a base particle of hard particles and a child particle which is familiar with molten cast iron is mixed with water glass to form a slurry. A core for casting, wherein the slurry is applied to the surface of a core.