JP2529271B2 - Cylinder block for V-type engine - Google Patents

Abstract

PURPOSE:To enable an oil return path to be easily formed by forming the oil return path opened respectively to the lower surface of a cylinder block and a cylinder head mounting surface of first and second paths extending from the respective opening surfaces perpendicularly thereto and drawing a pattern in casting. CONSTITUTION:A cylinder block 3 of a V-type engine is constituted from an upper block 1 and a lower block 2 connected thereto. The upper block 1 is formed with an oil return path 4 opened respectively to a lower surface 1a connected to the lower block 2 and a cylinder head mounting surface 1b. Then, the oil return path 4 is formed of a first path 7 extending from said lower surface 1a perpendicularly thereto and a second path 8 extending from said surface 1b perpendicularly thereto. And the second path 8 is joined in the intermediate portion of first path 7 so that the first path 7 is formed on the upper end with a bag-like space 9.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder block of a V-type engine, and more particularly to a structure of an oil return passage thereof.

(Prior Art) A cylinder block of a V-type engine in which a cylinder head mounting surface is inclined with respect to a lower surface of the cylinder block has been known (see, for example, JP-A-61-135968).

(Problems to be Solved by the Invention) However, in such a cylinder head, since the lower surface of the cylinder block and the cylinder head mounting surface are in a slanted positional relationship, it is necessary to form an oil return passage opening on both surfaces. It is difficult.

The present invention has been made in view of the above points, and an object of the present invention is to provide a cylinder block of a V-type engine in which an oil return passage can be easily processed and oil can be separated when oil is blown up.

(Means for Solving the Problems) The present invention is premised on a V-type engine having an oil return passage opening to a cylinder block lower surface and a cylinder head mounting surface inclined with respect to the cylinder block lower surface. Is.

According to the present invention, in order to achieve the above object, the oil return passage includes a first passage extending from a lower surface of a cylinder block in a direction orthogonal to the lower surface, and a first passage extending from a cylinder head attachment surface in a direction orthogonal to the attachment surface. It is characterized in that it is composed of two passages, and the second passage merges with a middle portion of the first passage.

(Operation) Since both the first and second passages of the oil return passage extend in the direction orthogonal to the lower surface of the cylinder block and the mounting surface of the cylinder head, they can be easily formed by die cutting during casting.

In addition, since the second passage merges with the middle portion of the first passage, the upper end portion of the first passage serves as a bag-shaped space, and the bag-shaped space functions as an oil separator when oil blows up. To do.

(Example) Hereinafter, the Example of this invention is described based on drawing.

In FIG. 1 showing the overall configuration of a cylinder block of a V-type engine, 1 is an upper block, 2 is a lower block, and both blocks 1 and 2 are joined to form a cylinder block 3.
Is formed.

The upper block 1 has an oil return passage 4 that opens to a block lower surface 1a joined to the lower block 2 and a cylinder head mounting surface 1b to which a cylinder head (not shown) is mounted.

The oil return passage 4 is connected to another oil return passage 5 formed in the lower block 2 and extending in the vertical direction, and communicates with the crank chamber 6 through the oil return passage 5.

The oil return passage 4 is provided on the bottom surface 1a of the block.
It further comprises a first passage 7 extending in a direction orthogonal to the lower surface 1a and a second passage 8 extending in a direction orthogonal to the mounting surface 1b from the cylinder head mounting surface 1b. This second passage 8 has a first
It joins the middle part of the passage 7 and thereby the first
The upper end portion of the passage 7 forms a bag-shaped space 9. The bag-shaped space 9 has at least a depth substantially equal to the diameter of the first passage 7.

The bag-shaped space 9 is provided close to a water jacket 10 formed in the upper block 1.

In addition, the wall surface of the first passage 7 of the upper block 1 is partially cut out to form a cutout portion 11 at the time of die-cutting (see FIG. 2), and the lower block 2 corresponds to the upper block 1. By being joined to the lower side, the notch 11 and the upper surface of the lower block 1 form an oil escape hole.

In addition, in order to secure the minimum passage area, the second passage 8 is made to have a substantially uniform diameter over the whole by punching after die cutting.

According to the above configuration, the first and second passages 7 and 8 of the oil return passage 4 of the upper block 1 are formed by die-cutting during die casting of the upper block 1 made of aluminum alloy. The passages 7 and 8 and the oil escape hole (notch 11) can be easily formed.

Further, since the first passage 7 of the oil return passage 4 has the bag-shaped space 9 above the portion where the oil return passage 4 merges with the second passage 8, when the oil blows up, the bag-shaped space 9 is formed.
Can separate oil. In particular, since the bag-shaped space 9 is close to the water jacket 10, the oil separation effect based on the cooling by the cooling water is high. That is, the blow-by gas rising from the crank chamber 6 is cooled by the cooling water in the water jacket 10 in the bag-shaped space 9, and the oil is efficiently separated.

Further, during turning, etc., the oil surface is inclined to close the lower end portion of the oil return passage 5 of the lower block 2 (see the chain line S in FIG. 1), and the communication with the crank chamber 6 is cut off so that the oil return passage 5 is blocked. Even if oil does not escape through the passage 5 and accumulates in the passage 5, the oil escapes through the oil escape hole (notch 11) formed in the joint surface between the upper block 1 and the lower block 2 and the crank chamber 6
The second passage 8 does not overflow.

In the above-described embodiment, the notch 11 forming the oil escape hole is formed together with the passages 7 and 8 at the time of die cutting, but as shown in FIG. When the second passage 22 is drilled, the length of the portion to be drilled may be extended with respect to the wall surface of the first passage 21 to open the oil escape hole 23. 24
Is a bag-like space and 25 is a water jacket.

Although the above-described embodiment is applied to the cylinder block 3 in which the upper block 1 and the lower block 2 are joined, it can also be applied to one in which the entire cylinder block is integrally formed. Needless to say.

(Effects of the Invention) According to the present invention, as described above, the oil return passage is constituted by the first and second passages extending in the direction orthogonal to the lower surface of the cylinder block and the cylinder head mounting surface. A return passage can be formed. Further, since the second passage merges with the middle portion of the first passage, the bag-shaped space (first passage) formed above the middle portion separates the oil from the blow-by gas when the oil blows up. Can be achieved.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a sectional view of an essential part of a cylinder block of a V-type engine, FIG. 2 is an enlarged view seen from the direction A in FIG. 1, and FIG. It is a principal part sectional view of the cylinder block of the V-type engine about an Example. 1 …… upper block, 1a …… block lower surface, 1b …… cylinder head mounting surface, 2 …… lower block, 3 …… cylinder block, 4,20 …… oil return passage, 7,21 ……
1st passage, 8,22 …… 2nd passage, 9,24 …… Bag space, 10,2
5 …… Water jacket, 23 …… Oil escape hole.

Claims (1)

(57) [Claims] 1. A V-type engine having an oil return passage opening to a cylinder block lower surface and a cylinder head mounting surface inclined with respect to the cylinder block lower surface, wherein the oil return passage is lower than the cylinder block lower surface. And a second passage extending in a direction orthogonal to the mounting surface from the cylinder head mounting surface, and the second passage is joined to a midway portion of the first passage. Cylinder block for V-type engine.