JPH03463A - Manufacture of cylinder block - Google Patents

Abstract

PURPOSE:To stabilize the quality by forming a cutout part to a part corresponding to an upper deck, fitting a metal-made water passage piece packed with packing material to cylinder head side of this cutout part remaining space to be the upper deck, executing casting and discharging the packing material. CONSTITUTION:The cutout part 18 is formed to the part corresponding to the upper deck 4 in an annular water jacket metallic mold 15 to form a water jacket 3. After fitting the flat cylindrical shaped metal-made water passage piece 5 packed with the packing material of sand 20, etc., in inner part thereof to this cutout part 18 remaining the prescribed space to be formed to the upper deck at the cylinder head side of the cutout part, the casting is executed. After casting, by discharging the packing material in this water passage piece remaining the water passage piece included as internal chill in a cylinder block, the cooling water passage is formed. By this method, as the positioning accuracy of the water passage piece is good and the developments of crack and deformation are eliminated, the cylinder block having the stable quality without dispersions of the shape and dimension can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a cylinder block for an internal combustion engine by a pressure casting method, and more particularly to a method of manufacturing a so-called semi-closed type cylinder block having an upper deck.

2. Description of the Related Art A method for manufacturing this type of cylinder block is disclosed, for example, in Japanese Patent Application Laid-Open No. 51-232654.

In this conventional method, a plurality of notches opening downward are formed in advance in an annular water jacket mold to form a water jacket, and a sand core is inserted into the notches with a predetermined space left above. Casting is performed in the set state, and the sand core is discharged after casting to integrally obtain an upper deck that closes a part of the upper surface of the water jacket.

Problems to be Solved by the Invention However, according to the above-mentioned conventional methods, it is extremely difficult to maintain the shape of the core due to the high pressurizing force of the molten metal, which is a special feature of pressure casting, and the core may crack. Alternatively, deformation is likely to occur, and due to the contact between the metal and sand, the positioning accuracy between the water shaker/soto mold and the core is insufficient, and there is a limit to improving the shape accuracy of the product.

Also, by discharging the sand core after casting, a cooling water passage will be formed in the core, but in order to insert the molten metal into the sand core, it is necessary to completely discharge and remove the sand core. is difficult, and the formation of cooling water passages tends to be uncertain.

The present invention was made in view of the above problems.
Instead of a sand core, an easy-to-handle metal channel piece filled with filler such as sand is used for casting, and after casting, only the filler inside the channel piece is discharged, leaving the channel piece behind. By doing so, it is an object of the present invention to provide a method for manufacturing a cylinder block in which a cooling water passage can be reliably secured at the same time as the upper deck is formed.

Means for Solving the Problems As described above, the present invention is a method for manufacturing a cylinder block having an upper deck by a pressure casting method, and the present invention is applicable to a new problem in an annular water jacket mold in which a water jacket is to be formed. A flat cylindrical piece of metal formed by forming a cutout in the part where the cutout is, and filling the inside of the cutout with a filler such as sand, leaving a predetermined space on the cylinder head side of the cutout to serve as an upper deck. After casting, the cooling water passage is formed by fitting the waterway piece made of aluminum and then casting, and after casting, leaving the waterway piece cast in the cylinder block and discharging the filler in the waterway piece. It is a feature.

Effect According to the above method, the metal waterway piece is integrally cast below the upper deck after casting, so the upper deck can be removed by discharging only the filler in the waterway piece, leaving the waterway piece. A cooling water passage is formed below.

Embodiment Figures 2 to 5 are diagrams showing an example of a product manufactured by the method of the present invention.・yt<de Below the tube 4, a flat cylindrical waterway piece 5 is integrally cast with the cylinder block 1. Since both side surfaces of the water channel piece 5 are open, adjacent water jackets 3, 3 are communicated with each other via the cooling water passage 6 in the water channel piece 5.

This cylinder block l is manufactured by a pressure casting method (pressure die casting method) using, for example, a mold 7 shown in FIG. 6, and includes a crankcase mold 9 on the lower mold 8 side,
A pair of horizontal molds 10 and 10, and a bore mold 1 on the upper mold 11 side
This is done by filling the product part space (cavity) 13 defined by 2 with molten aluminum alloy M from the gate 14. 15 is a water jacket mold integrally formed with the bore mold 12, 16 is a sleeve, and 17 is a plunger.

During such pressure casting, as shown in FIG. Casting is performed with a flat cylindrical metal waterway piece 5 fitted therein.

As shown in FIGS. 7 and 8, the waterway piece 5 is made by press-forming a steel plate of a predetermined thickness into a flat cylindrical shape, filling the inside with anti-sand 20 as a filler, and firing it. As shown in FIG. 1, the water channel piece 5 is positioned and fitted into the notch 18 into the cylinder, leaving a space 19 on the throat side to serve as the upper deck 4. When casting is performed using the water jacket mold 15 fitted with such a waterway piece 5, the waterway piece 5 is integrally cast below the upper deck 4, as shown in FIG. 9 and FIG. 1O. Being surrounded.

Next, regarding the cylinder block 1 in which the waterway piece 5 is cast, the sand protection 20 inside the waterway piece 5 is removed.
When only the water is collapsed and discharged, the inside of the water channel piece 5 functions as a cooling water passage 6 which is a part of the quarter jacket 3, as shown in FIGS. The water jackets 3.3 will be interconnected.

Here, it is not necessary to use steel as the material for the water channel piece 5, and any metal material having a melting point equal to or higher than that of an aluminum alloy may be used. Moreover, it is possible to use granular materials other than anti-sand as a filler.

Effects of the Invention As described above, according to the present invention, an L-shaped waterway piece filled with a filler such as sand is integrally cast, and the waterway piece is left behind after casting. By discharging only the internal filler to form the cooling water passage, part of the contact between the water jacket mold and the waterway piece is metal, which improves the positioning accuracy of the waterway piece. Unlike conventional sand cores, there is no cracking or deformation, so cylinder blocks with stable quality and no variations in shape or size can be obtained.

Furthermore, the filling material inside the channel piece is covered by the channel piece and does not come into direct contact with the molten metal, so there is no need to insert the molten metal. Since the cooling water passage is formed by leaving the sand core and the molten metal, the formation of the cooling water passage does not become uncertain unlike the conventional method in which the sand core and the molten metal come into direct contact with each other.

In addition, although the inside is filled with a filler material, the waterway piece itself is made of metal, so it is easy to handle (for example, the work of setting the waterway piece into a water jacket mold can be easily automated).

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the main part of the water jacket core used in the present invention, Fig. 2 is a plan view of the cylinder block obtained by the present invention, and Fig. 3 is a main part of the cylinder block with a part cut away. Perspective view, Figure 4 is IV-■ of Figure 3
5 is a plan view of the main part of FIG. 3, FIG. 6 is a sectional view showing an example of the mold used in the present invention, FIG. 7 is a perspective view of the water channel piece, and FIG. 8 is a sectional view taken along the line. is a cross-sectional view taken along the line ■-■ in Fig. 7, Fig. 9 is a perspective view showing a main part of the cylinder block after casting and before sand control discharge, and Fig. 1O is a cross-sectional view taken along the line X-- in Fig. 9. FIG. 3 is a cross-sectional view taken along the X-ray. 1... Cylinder block, 3... Water jacket, 4... Upper deck, 5... Channel piece, 6...
...Cooling water passage, 15...Water jacket mold,
18. Notch, 19... Space, 20... Sand control as a filler. Fig. 9 Fig. 10

Claims (1)

[Claims] (1) In a method for manufacturing a cylinder block having an upper deck by a pressure casting method, a notch is formed in a portion of the annular water jacket mold in which the water jacket is to be formed that corresponds to the upper deck, and the cylinder block in this notch is A step of casting after fitting a flat cylindrical metal waterway piece filled with a filler into the notch, leaving a predetermined space on the head side that will become the upper deck; and then forming a cooling water passage by leaving the water passage piece cast in the cylinder block and discharging the filler in the water passage piece.