JPH07286553A - Manufacture of cylinder block - Google Patents

Abstract

PURPOSE:To provide a cast steel cylinder block of high quality generating no blow hole at casting by casting cylinder block pieces divided into small blocks out of cast steel, and thereafter forming these cylinder block pieces into one body by welding. CONSTITUTION:When a cylinder block 1 is manufactured, cylinder block pieces 4a-4c cut into round slices at dividing faces 3 between adjoining two main bearing parts 2, 2 are cast out of cast steel. Adjoining cylinder block pieces 4a-4c are butted with each other, beveling parts are formed, and the beveling parts are welded so as to combine them together into one body. Such cylinder block 1 is manufactured out of cast steel of high Young's modulus, and hence the strength is high and the weight can be reduced due to the high strength. Casting is carried out against every cylinder block piece 4a-4c, and hence generation of blow holes can be restrained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diesel engine, and more particularly to a method for manufacturing a cylinder block in a medium speed diesel engine.

[0002]

2. Description of the Related Art Cylinder blocks for medium speed diesel engines are generally integrally cast from cast iron or nodular cast iron.

[0003]

However, cast iron and nodular cast iron have a low Young's modulus and are not high in strength. Therefore, if it is attempted to increase the strength and prevent deformation, particularly displacement of the shaft center of the main bearing portion, the cylinder block inevitably increases in wall thickness and weight.

On the other hand, it is possible to integrally manufacture the cylinder block with cast steel having a high Young's modulus. However, the cast steel has a high viscosity and the flow of molten metal is poor, so that cavities are likely to occur and a high quality cylinder block is integrated. Is difficult to cast. The present invention is made in order to overcome such conventional problems, and its object is to be relatively lightweight and high-strength, and deformation, particularly, the deviation of the main shaft of the main bearing portion is unlikely to occur, Moreover, it is an object of the present invention to provide a method for manufacturing a high-quality cast-steel cylinder block in which cavities are not generated during casting.

[0005]

That is, in the method for manufacturing a cylinder block of the present invention, after the cylinder block pieces divided into small blocks are cast from cast steel, these cylinder block pieces are integrated by welding. It is a feature. Here, it is preferable that the cylinder block piece includes a main bearing portion.

[0006]

As described above, after the cylinder block pieces divided into the small blocks are cast by the cast steel and then these cylinder block pieces are integrated by welding, they are relatively lightweight and have high strength and are deformed, particularly It is possible to manufacture a cylinder block made of high-quality cast steel in which the axial center of the main bearing portion is less likely to be displaced and cavities are not generated during casting.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a perspective view of a cylinder block manufactured by the method of the present invention, and FIG. 2 is a vertical cross-sectional view of the cylinder block manufactured by the method of the present invention. When manufacturing the cylinder block 1, as shown in FIG. Adjacent to 2
Cylinder block pieces 4a, 4b, 4b, 4c, which are sliced along the dividing surface 3 between the two main bearing portions 2, 2, are cast from cast steel.

Since the two cylinder block pieces 4b in the middle part except the cylinder block pieces 4a and 4c located at both ends of the cylinder block 1 have the same shape, they can be cast by the same mold. Next, when manufacturing the cylinder block 1 having the six cylinder holes 5, as shown in FIG.
As described above, the left end cylinder block piece 4a and one of the middle cylinder block pieces 4b are combined to form the groove portion 6, and then the groove portion 6 is welded and joined.

Next, as shown in FIG. 3 (b), the groove portion 6 is formed by aligning the second intermediate cylinder block piece 4b to the right of the first intermediate cylinder block piece 4b. After that, the groove portion 6 is welded and joined. Next, as shown in FIG. 3C, the cylinder block piece 4c at the right end is located to the right of the cylinder block piece 4b at the second middle portion.
After forming the groove portion 6 by combining the above, the groove portion 6 is welded and joined. In addition, the code | symbol 7 has shown the welding part.

As described above, since the cylinder block 1 of the present invention is made of cast steel having a high Young's modulus, it has high strength and can be lightened accordingly. Moreover, since the cylinder block 1 is cast in each of the cylinder block pieces 4a, 4b, 4c divided into small blocks, cavities are unlikely to occur. Further, the cylinder block pieces 4a, 4 which are not easily deformed
Since the cylinder block 1 is formed by welding b and 4c together, there is no deviation of the axis of the main bearing portion 2.

In the above description, the case where the cylinder block pieces each having a shape obtained by cutting the cylinder block into a circle is assembled has been described, but as shown in FIG. 4, the cylinder block piece 40 in which the lower half of the cylinder block is cut into a circle.
The same effect can be obtained by assembling a, 40b, 40b, 40c and cylinder block pieces 8, 9 whose upper body part is divided into two in the longitudinal direction. Furthermore, the two cylinder block pieces 8 and 9 of the upper half of the cylinder block of FIG. 4 are further divided into four pieces 8a, 8b, 8b, 8c and 9a, 9b, 9b, 9c as shown in FIG. However, the same effect can be obtained. 4 and 5, reference numeral 3 indicates a dividing surface, 5 indicates a cylinder hole, and 7 indicates a welded portion.

[0012]

As described above, according to the present invention, the cylinder block pieces divided into the small blocks are cast from cast steel, and these cylinder block pieces are integrated by welding, so that the cylinder block pieces are lightweight and have high strength. And deformation, especially,
It has become possible to manufacture a high-quality cast steel cylinder block in which the main bearing portion has no axial misalignment and which does not have cavities during casting.

In other words, the present invention has the following advantages. a) By making the cylinder block into smaller blocks,
The casting capacity can be reduced, and the degree of freedom of casting ability is increased. b) By stocking common blocks in the middle part,
It can respond to changes in the number of cylinders and shorten the delivery time. c) By reducing the size of the cylinder block, casting defects in each cylinder block can be minimized, and quality and inspection efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a cylinder block manufactured by the method of the present invention.

FIG. 2 is a vertical cross-sectional view of a cylinder block manufactured by the method of the present invention.

3 (a), (b), (c) are explanatory views showing a cylinder block manufacturing process of the present invention.

FIG. 4 is a perspective view showing another embodiment of the cylinder block manufactured by the method of the present invention.

FIG. 5 is a perspective view showing still another embodiment of the cylinder block manufactured by the method of the present invention.

[Explanation of symbols]

 1 Cylinder block 4a, 4b, 4c Cylinder block piece

Claims (2)

[Claims] 1. A method of manufacturing a cylinder block, which is produced by casting a cylinder block piece divided into small blocks with cast steel and then integrating these cylinder block pieces by welding. 2. The method of manufacturing a cylinder block according to claim 1, wherein the cylinder block piece includes a main bearing portion.