JPS592578B2 - Cylinder block manufacturing method and cylinder block - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cylinder block for a water-cooled engine.

As shown in Fig. 1, a water-cooled engine generally used in automobile engines has a water jacket 2 provided around the outer periphery of the engine cylinder 1 to form a water passage, and a radiator 3 cools the water. water pump 4
The engine is cooled by circulating between the outer periphery of the cylinder 1 of the engine and the radiator 3.

In order to improve the cooling effect of the cylinder 1 by this cooling water and to uniformly cool the entire cylinder 1, each cylinder 1 is formed to be independent as shown in FIG. Although it is necessary to provide a passage 5 for circulating cooling water between each cylinder 1, each cylinder 1
Although the cooling effect is improved by increasing the space between the two passages and making the passage 5 larger, the problem of increasing the size of the engine as a whole arises, so it is preferable to make the passage 5 as narrow as possible.

However, the cylinder block 6 consisting of the cylinder 1 and water jacket 2 of the engine as described above is made of a main mold (usually called a mother mold) and a core 7 such as a sand mold as shown in FIG. When only a sand mold core 7 made of shell sand or the like is used, the wall thickness T of this part 8 is limited due to the strength limitations of the sand mold part 8 for forming the passage 5 between each cylinder. Since the width of the passage 50 formed between each cylinder 1 cannot be reduced to 5 to 6 mm or less, there is a limit to the reduction in size and weight of the engine.

Therefore, in the core used when casting cylinder blocks, a reinforcing core support is interposed in the part for forming cooling passages between each cylinder, so that this part can be made thinner than before. The above-mentioned drawbacks have been eliminated, and the details of the present invention will be described below with reference to embodiments shown in the drawings.

FIGS. 3a and 3b are a plan view and a sectional view taken along the line I-I of the core 10 used when casting the cylinder block according to the present invention, and cooling water or the like passes between each cylinder of the core 10. A recess 12 is provided in the lower part of the portion 11 forming the passage, as shown in FIG. Let's do it like this.

If the strength of the portion 110 forming the passage of the core 100 is improved in this way, the thickness T of this portion 11 can be reduced to 3 mm.
It becomes possible to form the film as thin as possible.

Then, if a cylinder block is cast using the core 10, each cylinder 1 as shown in FIGS.
4 are independent from each other, and a cylinder block 16 can be obtained in which the width of the cooling passage 150 for cooling water, etc., formed between each cylinder 14 is narrowed, and this cylinder block 1
By using 6, the engine can be made smaller and lighter.

When casting a cylinder block using this core 10, the lower ends of each cylinder 14 are connected,
The core support 13 used for reinforcing the core remains in this connection part 17, integrated with the cylinder block 16, but the above-mentioned Since the cooling passage 15 for cooling water and the like is formed in this manner, the cooling efficiency of the engine will not be reduced.

Further, as shown in FIG. 5, the dimension H of the cooling passage 150 is the lower part of the set ring when the piston P, which moves up and down in the cylinder and has piston rings R1, R2, and R3 as a set ring, reaches the bottom dead center. It is desirable that the dimensions be such that the ring R3 is located therein.

As explained above, the cylinder block of the present invention has a structure that surrounds the circumference of each cylinder at the upper part thereof, and
It has a cooling water passage with a narrow width dimension in the cylinder arrangement direction, and has a connecting part connecting the cylinder walls in the cylinder arrangement direction at the lower part of the periphery of each cylinder, and within the wall thickness of the connecting part in the cylinder arrangement direction. Since each cylinder is equipped with a thin plate-like core support buried perpendicular to the cylinder, each cylinder is independent, and there is a cooling water passage around the top of each cylinder, so the top of the cylinder, which becomes the combustion chamber, can be directly connected to the cylinder. It can be cooled with cooling water, improving the cooling effect, and since the width dimension in the cylinder arrangement direction is narrow, the cylinder block can be made smaller and lighter. A connecting part is provided to connect the walls in the cylinder arrangement direction, and a thin plate-shaped core support is embedded within the thickness of this joint part perpendicular to the cylinder arrangement direction, so that the strength of the base part of the independent cylinder can be increased. It is possible to increase the reinforcing effect against stress concentration on the base plate due to membrane vibration of the cylinder wall, etc., which occurs when the piston moves from the top dead center and bottom dead center to the next stroke.

In addition, the method for manufacturing a cylinder block of the present invention includes arranging a plurality of cylinder bores in a row at equal intervals, forming the entire block into a rectangular block shape with core sand, and forming cooling water passages between each cylinder bore. It has a thin passage forming part in the upper part, has a cutout recessed part for forming a connecting part of the cylinder wall in the lower part of this part, and has a thin plate-shaped reinforcing core support in the lower four parts perpendicular to the arrangement direction of the cylinders. Since the core is placed in the mother mold and cast with both ends buried in the core sand, the cooling water passage between the cylinder bores can be narrowed, which makes the cylinder block smaller and lighter. In addition, since a cooling water passage is formed in the upper part of the periphery of each cylinder, the cooling effect can be improved. Since the connecting portion is provided with a reinforcing core support in the form of a thin plate, the strength of the core can be improved, and the strength of the lower portion around each cylinder can also be improved.

[Brief explanation of drawings]

Fig. 1 is a partial sectional view showing a water-cooled engine, Fig. 2 is a drawing showing a conventional example of a core used when casting a cylinder block for a water-cooled engine, and Fig. 3a is a drawing of a core according to the present invention. FIG. 3 is a plan view, FIG. 3 is a cross-sectional view taken along the line I--I, FIG. 4 is a cross-sectional view showing a cylinder block cast using the core according to the present invention, and FIG. 5 is a vertical cross-sectional view. 10... Core, 11... Part forming a passage, 13... Core support, 14...
Cylinder, 15... Passage, 16... Cylinder block.

Claims (1)

[Scope of Claims] 1. At the upper part of the periphery of each cylinder, surrounding the periphery of the cylinder,
It has a cooling water passage with a narrow width dimension in the cylinder arrangement direction, and has a connecting part connecting the cylinder walls in the cylinder arrangement direction at the lower part of the periphery of each cylinder, and the cylinders are arranged within the wall thickness of the connecting part. A cylinder block for an engine having an independent cylinder, characterized by comprising a thin plate-shaped core support buried perpendicular to the direction. 2 A plurality of cylinder bores are arranged in a row at equal intervals, the whole is formed into a rectangular block shape with core sand, and has a thin passage forming part at the top to form a cooling water passage between each cylinder bore. The lower part has a cutout recess for forming a connecting part of the cylinder wall, and a reinforcing core support in the form of a thin plate is buried in the lower recess at right angles to the arrangement direction of the cylinders, with both ends embedded in the core sand. 1. A method for manufacturing a cylinder block for an independent cylinder engine, characterized in that a core installed in the same state is placed in a master mold and cast.