JPH03138065A - Manufacture of cast iron-made cylinder block - Google Patents

Abstract

PURPOSE:To integrate a cylinder liner and an internal chilling material and to strengthen mechanical connection by arranging pouring basin part for molten metal in inner part of bore core at the time of manufacturing a cast iron-made cylinder block. CONSTITUTION:The pouring basin parts 5, 5 are arranged in the bore core part 3 and communicated with a runner 7 through a flowing passage 6 formed in vertical direction in inner part of the core 4. Then, the pouring basin parts 5, 5 are arranged at side part facing to the Y direction in inner circumferential face of the cylinder liner 2, i.e., as approaching position facing to place, where it is difficult to hold at the high temp. after pouring the molten metal. Further, the molten metal for internal chilling material is poured and filled up into a mold M from a sprue 8, and after solidifying, the mold M and core 4 are removed to obtain the cast iron-made cylinder block. Therefore, side part of the liner 2 is heated with radiant heat of the pouring basin parts 5, 5 and the temp. uniformity in the whole circumference of liner 2 is improved and the mechanical connection between the liner 2 and the internal chilling material is strengthened.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a cast iron cylinder block for an engine.

(Prior art) Today, as automobile parts become lighter and lighter, technology is being developed to make engine cylinder blocks smaller and lighter. Blocks etc. have been put into practical use.

When producing the above-mentioned aluminum alloy cylinder block, a cast iron cylinder liner is generally cast with an aluminum alloy, as disclosed in, for example, Japanese Patent Laid-Open No. 58-211550.

By the way, in the case of a diesel engine, the heat load conditions are more severe than that of a gasoline engine, and NVH (noise,
Highly rigid cast iron cylinder blocks are still being used due to the high demand for improvements in characteristics (vibration, vergeness), but as engines become faster and more powerful, the wear resistance of piston sliding surfaces must be further improved. It has become necessary. In that case, from an economic point of view, it would be a good idea to install a cylinder liner made of a material with high wear resistance in the bore of a normal cast iron cylinder block, but when manufacturing a cylinder block, a cast iron liner is If a method of press-fitting into the bore of the cylinder block is adopted, it is necessary to secure an allowance for press-fitting, and the overall length of the cylinder block becomes long, making it impossible to satisfy the demand for miniaturization.

For the above reasons, in a diesel engine, it is judged to be most effective to construct a cylinder block by encasing a cast iron cylinder liner with excellent wear resistance in cast iron.

However, due to stains between the cylinder liner and the molten metal in the manufacturing process of the cast iron cylinder block or problems with uniformity of cooling after casting, a problem arises in that the cylinder liner is not partially fused and integrated with the casting material. In other words, the casting material between the bores of the cylinder is thick and maintains a relatively high temperature, so it is easy to join, but the parts other than between the bores, for example, the side faces facing perpendicular to the bore row direction, are thin. It was recognized that there was a problem in that bonding was not easy due to the fast cooling rate.

(Objective of the Invention) Therefore, an object of the present invention is to provide a method of manufacturing a cast iron cylinder block that can integrate the outer periphery of a cylinder liner and a casting material to strengthen the mechanical connection.

(Structure of the Invention) The present invention is a method for manufacturing a cast iron cylinder block, characterized in that a pool of molten metal is provided inside a bore core.

(Effects of the Invention) In the present invention, by providing a pool of molten metal inside the bore core, the heat retention inside the cylinder liner is improved.
It is possible to maintain a high temperature by slowing down the cooling rate of the molten metal around the cylinder liner. Therefore, the molten metal and the liner can be easily joined, and the liner and the cast material can be completely fused and integrated after solidification.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 3 is a schematic perspective view of a four-cylinder cylinder block manufactured according to the present invention, in which 1 is a cast iron cylinder block, and a cast iron cylinder liner 2 forming the inner circumferential wall of the bore B is attached by a casting. ing.

In this embodiment, the cylinder liner 2 contains 0.00% phosphorus.
Contains 6-1.0% by weight, Vickers hardness Hv is 250
Formed by cast iron with front and rear elevations. In addition, the casting material is cast iron (Fe1) with a Vickers hardness of around 200.
2), and the casting temperature is approximately 1400°C. In addition,
In Fig. 3, the bore row direction of cylinder block l is
The horizontal direction orthogonal to the bore row direction is the Y direction, and the vertical direction is the X direction.

FIG. 1 is a plan view of a mold M used for manufacturing a four-cylinder cast iron cylinder block as shown in FIG.
is the bore core part of the core 4 formed of sand, and the horizontal direction (Y direction) perpendicular to the bore row direction (X direction) in this bore core part 3 is
A pool 5.5 of molten metal is provided in a portion facing the cylinder liner 2 in the Y direction so as to be close to the inner circumferential surface of the side portion of the cylinder liner 2 in the Y direction. This easy pool 5.5 is filled with hot water through an inflow passage 6 formed in the vertical direction (X direction) inside the core 4.
! It communicates with i7. Then, the casting material as described above is poured into the mold M through the sprue 8 to fill it, and after solidification, the mold M and the core 4 are removed to obtain a cast iron cylinder block.

As explained above, in the embodiment, the molten water pool 5.5 is provided in the bore core part 3, but in particular, this molten water pool 5.5 is located on the inner peripheral surface of the cylinder liner 2 in the Y direction. By providing it close to the facing side, that is, the part that is difficult to maintain at a high temperature after pouring, the molten metal pool 5.
The side portions of the liner 2 are heated by the radiant heat of the liner 2, improving temperature uniformity around the entire circumference of the liner 2, and advantageously, the mechanical bond between the liner 2 and the casting material becomes stronger.

[Brief explanation of the drawing]

Fig. 1 is a partially omitted plan view of a cylinder block mold used in the implementation of the present invention, Fig. 2 is a vertical sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is a schematic diagram of the cylinder block. FIG. 1. Cylinder block 2. Cylinder liner 3-
Bore core part 4-core

Claims (1)

[Claims] A method for manufacturing a cast iron cylinder block in which the outer periphery of a cast iron cylinder liner is cast with cast iron, characterized in that a pool of molten metal is provided inside a bore core.