JP2001317404A - Semi-open-deck-type sylinder block - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semi-open-deck-type cylinder block having a coolant passage communicating from a water jacket formed on a cylinder head to a water jacket of the cylinder block through the inside of a partition between cylinder bores. SOLUTION: Ribs 6 as connection parts are formed between a projection 4a of the outer wall 4 of the cylinder block and a partition 3a of a cylinder liner 3. Each of the top surfaces of the ribs 6 is provided with an opening 9 of a coolant passage. The coolant passage communicates from the opening 9 to the water jacket 5 formed on the cylinder block 2 through the inside of the partition 3a. Thus, a clearance can be formed between the opening 9 of the coolant passage and the cylinder bore 2, and a gasket is arranged in the clearance to seal between the cylinder bore 2 and the opening 9 of the coolant passage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semi-open deck type cylinder block used for an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, closed deck type cylinder blocks, open deck type cylinder blocks and semi-open deck type cylinder blocks have been devised as cylinder blocks used in internal combustion engines.

[0003] A closed deck type cylinder block is a cylinder block in which the upper part of a water jacket between a cylinder liner and an outer wall of the cylinder block is covered by a cylinder deck portion. The closed deck type cylinder block is characterized in that the upper portion of the cylinder liner is connected to the outer wall of the cylinder block by a cylinder deck portion, so that the rigidity thereof is relatively high. But,
There is a problem that the upper part of the cylinder liner to which the cylinder deck is connected cannot be sufficiently cooled by the cooling water in the water jacket.

[0004] What is an open deck type cylinder block?
This is a cylinder block having a structure in which the cylinder liner and the outer wall of the cylinder block are connected only at the lower part of the cylinder block. Open deck type cylinder block
It is characterized in that the upper part of the cylinder liner can be sufficiently cooled by the cooling water in the water jacket. However, since the cylinder liner and the outer wall of the cylinder block are connected only at the lower part of the cylinder block, there is a problem that the rigidity is reduced.

[0005] A semi-open deck type cylinder block is provided between a cylinder liner and a cylinder block outer wall.
This is a cylinder block in which a rib connecting the cylinder liner and the outer wall of the cylinder block is partially formed. The semi-open deck type cylinder block is intended to combine the features of the open deck type cylinder block and the closed deck type cylinder block, and can cool the upper part of the cylinder liner and have high rigidity.
For example, Japanese Patent Application Laid-Open No. 8-61139 discloses a semi-open deck type cylinder block.

As shown in FIGS. 4 and 5, a semi-open deck type cylinder block disclosed in Japanese Patent Application Laid-Open No. 8-61139 has a rib 3 connecting a cylinder liner 5 and an outer wall of the cylinder block. The cylinder liner 5 has two locations, an upper portion and a central portion, and is disposed at an intermediate position of the head bolt hole 4 in the circumferential direction. By doing so, the deformation of the cylinder liner 3 is prevented, and the local excessive deformation of the periphery of the head bolt hole due to the tightening force of the head bolt is dispersed and averaged to reduce the deformation of the cylinder liner 3. is there.

In recent years, the overall length of the engine body has been reduced in order to reduce the size of the engine. For this reason, a siamese structure in which adjacent cylinder bores are integrated by a partition wall has been adopted. However, in this structure, since the space between the cylinder bores is integrated by the partition wall, cooling between the cylinder bores may not be sufficiently performed by the cooling water in the water jacket.

[0008] Therefore, in the closed deck type cylinder block, a cooling water passage communicating with a water jacket formed in the cylinder block through a water jacket formed in the cylinder head through the inside of the partition between the cylinder bores is formed. Thus, a method of cooling between the cylinder bores has been devised.

[0009]

However, when the above-described cooling water passage is to be formed in the semi-open deck type cylinder block, the opening of the cooling water passage in the upper surface of the cylinder block is formed in the upper surface of the partition wall. I have to do it. Then, the distance between the cylinder bore and the opening of the cooling water passage becomes very small.
Then, there is a problem that it is very difficult to arrange the gasket at the narrow interval and seal the opening of the cylinder bore and the cooling water passage.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a water jacket of a cylinder block through a water jacket formed in a cylinder head and a partition wall between cylinder bores. An object of the present invention is to provide a semi-open deck type cylinder block in which a communicating cooling water passage is formed.

[0011]

According to the first aspect of the present invention, a plurality of cylinder liners are integrated at a partition wall, and a water jacket is formed between the cylinder liner and an outer wall of a cylinder block. In a semi-open deck type cylinder block in which the upper part of the cylinder liner and the outer wall of the cylinder block are partially connected,
A connecting portion is formed between a partition between two adjacent cylinder bores and an outer wall of the cylinder block, and an opening of a cooling water passage is formed on a top surface of the connecting portion or on a top surface of the outer wall of the cylinder block on an extension of the partition. The cooling water passage extends from the opening through the inside of the partition and reaches the water jacket.

According to a second aspect of the present invention, in the semi-open deck type cylinder block according to the first aspect, the top surface of the connecting portion is formed on the same plane as the top surface of the outer wall of the cylinder block. Was the gist.

According to a third aspect of the present invention, in the semi-open deck type cylinder block according to the first or second aspect, a head bolt formed on an upper surface of the semi-open deck type cylinder block is screwed. The gist of the invention is that the counterbore depth of the head bolt hole is set to a position at an intermediate position with respect to the height of the connecting portion.

(Operation) According to the first aspect of the present invention,
Since the opening of the cooling water passage is formed on the top surface of the outer wall of the cylinder block on the extension of the connecting portion or the partition, a space can be provided between the cylinder bore and the opening.

According to the second aspect of the present invention, when the cylinder head is fixed to the upper part of the cylinder block, a head bolt is passed from the upper part of the cylinder head, and the head bolt is inserted into a head bolt hole formed in the cylinder block. Is screwed, the force of pulling in the lateral direction does not act on the connecting portion due to the tightening force of the head bolt, and only the force of pulling upward acts.

According to the third aspect of the invention, the tightening force of the head bolt is efficiently transmitted to the cylinder liner through the connecting portion.

[0017]

FIG. 1 shows an embodiment of a semi-open deck type cylinder block according to the present invention.
3 will be described with reference to FIG.

FIG. 1 is a top view of a semi-open deck type cylinder block of the present embodiment, and FIG.
FIG. 3 is a cross-sectional view taken along a line BB in FIG. 1.

As shown in FIG. 1, a semi-open deck type cylinder block (hereinafter simply referred to as a cylinder block) 1 of an internal combustion engine is provided with a plurality (four in the figure) of cylinder bores 2 in series in the longitudinal direction. 3 and is formed. The cylinder liner 3 is integrally connected between two adjacent cylinder bores 2 by a partition wall 3a.

Outside the cylinder liner 3, a cylinder block outer wall 4 is arranged at intervals. The cylinder liner 3 and the cylinder block outer wall 4 are connected at the lower part of the cylinder block 1.

The space between the cylinder liner 3 and the cylinder block outer wall 4 is a water jacket 5 which serves as a passage for cooling water. As shown in FIG. 3, the water jacket 5 reaches the lower part of the cylinder liner 3.

The cylinder block outer wall 4 is located near both ends of the partition wall 3a (in FIG. 1, both ends of the partition wall 3a in the width direction of the cylinder block 1), as shown by dotted lines in FIG. It protrudes to the 3a side, and a protrusion 4a is formed. Also, in FIG. 1, four corners of the cylinder block 1 bulge toward the cylinder liner 3 side, and a protruding portion 4b is formed.

A rib 6 as a connecting portion is formed between the protrusion 4a and the partition 3a.

The rib 6 is connected to the projection 4a and the partition 3 so as to connect the projection 4a to the end of the partition 3a.
a is integrally formed. Further, as shown in FIG. 2, the rib 6 reaches a certain depth from the top surface of the cylinder block, and a water jacket 5 is provided below the rib 6. In FIG. 1, the water jackets 5 adjacent to each other with the rib 6 interposed therebetween communicate below the rib 6. Further, the top surface of the rib 6 is in contact with the cylinder liner 3.
And on the same plane as the top surface of the cylinder block outer wall 4.

A head bolt hole 7 is formed in each of the protrusions 4a and 4b.

As shown in FIG. 2, the head bolt hole 7 is formed by a counter bore 7a and a female thread 7b. No thread is formed in the counterbore portion 7a, and a thread is formed in the female thread portion 7b.
Also, a boundary surface 7c between the counter bore 7a and the female thread portion 7b.
Is located at an intermediate position with respect to the height direction of the rib 6.

As shown in FIG. 1, openings 9 of cooling water passages 8 are formed on the top surfaces of the ribs 6, respectively.

The cooling water passage 8 communicates with the water jacket 5 formed in the cylinder block 1 from the opening 9 via the inside of the partition 3a. or,
As shown in FIG. 1, the cooling water passage 8 communicates with the water jacket 11 formed in the cylinder head 10 at the opening 9. Cooling water in the water jacket 5 formed in the cylinder block 1 flows through the cooling water passage 8 to the water jacket 11 formed in the cylinder head 10 via the opening 9.

The cylinder head 10 is connected to the cylinder block 1
When fixing to the upper part of the cylinder block, a gasket 12 for sealing the cylinder bore 2, the water jacket 5, the opening 9 of the cooling water passage 8, and the like is sandwiched between the lower surface of the cylinder head 10 and the upper surface of the cylinder block 1. . Then, the male screw portion of the head bolt reaching the cylinder block 1 from the upper portion of the cylinder head 10 is screwed into the female thread portion 7b of the head bolt hole 7 formed in the cylinder block 1, and the cylinder head 10 is fixed to the cylinder block 1. I do.

Next, the features of the semi-open deck type cylinder block configured as described above will be described below.

(1) A rib 6 is formed between the end of the partition wall 3a of the cylinder liner 3 and the outer wall 4 of the cylinder block.
Since the opening 9 of the cooling water passage 8 is formed on the top surface of the rib 6, an interval at least as large as the thickness of the cylinder liner 3 can be provided between the opening 9 and the cylinder bore 2. Therefore, the gasket 12 can be disposed at an interval between the opening 9 of the cooling water passage 8 and the cylinder bore 2, and the gasket 12 can seal the cylinder bore 2 and the opening 9 of the cooling water passage 8.

(2) When fixing the cylinder head 10 to the cylinder block 1 with a head bolt, if the top surface of the rib 6 is lower than the top surfaces of the cylinder liner 3 and the cylinder block outer wall 4, tightening by the head bolt is performed. In the present embodiment, the top surface of the rib 6 is formed flush with the top surfaces of the cylinder liner 3 and the cylinder block outer wall 4. Therefore, the force that is pulled in the lateral direction does not act on the rib 6, but only the force that is pulled upward acts. Therefore, since the cylinder liner 3 is stretched only upward by the rib 6, the top surface of the cylinder liner 3 is strongly pressed against the lower surface of the cylinder head 10, and the sealing performance of the cylinder bore 2 is improved.

(3) Since the counterbore depth 7a of the head bolt hole 7 is set at an intermediate position with respect to the height direction of the rib 6, the tightening force of the head bolt is transmitted through the rib 6, and the cylinder liner 3 It is transmitted efficiently. Therefore, the top surface of the cylinder liner 3 is strongly pressed against the lower surface of the cylinder head 10, so that the sealing performance of the cylinder bore 2 is improved.

(4) When a large number of ribs are formed as in the prior art, the cylinder liner 3 is stretched in many directions by the tightening force of the head bolt and deformed in a complicated manner. Since the ribs 6 are formed only near both ends of the partition wall 3a, the cylinder liner 3 only needs to be deformed relatively simply. Therefore, when the cylinder liner 3 is deformed, a gap is formed between the piston and the cylinder liner 3, and it is possible to prevent the lubricating oil from remaining in the combustion chamber through the gap and burning the lubricating oil. Therefore, the consumption of the lubricating oil can be reduced and the seizure of the piston can be eliminated.

The embodiment of the present invention is not limited to the above embodiment, but may be implemented as follows.

In the present embodiment, the opening 9 of the cooling water passage 8 is formed on the top surface of the rib 6, but the opening 9 is formed on the cylinder block outer wall 4 on the extension of the partition wall 3a of the cylinder liner 3. It may be formed on the top surface. In such a case, it is necessary to change the position of the head bolt hole 7 such as by moving the position of the head bolt hole 7 to the outer wall side of the cylinder block 1.

[0037]

According to the first aspect of the present invention, since the gasket can be disposed between the cylinder bore and the opening of the cooling water passage, the cylinder bore and the opening can be sealed.

In addition, according to the second and third aspects of the present invention, since the top surface of the cylinder liner is strongly pressed against the lower surface of the cylinder head, the sealing performance of the cylinder bore can be improved.

[Brief description of the drawings]

FIG. 1 is a top view of a semi-open deck type cylinder block 1 of the present embodiment.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a sectional view taken along line BB in FIG. 1;

FIG. 4 is a top view of a conventional semi-open deck type cylinder block.

FIG. 5 is a side sectional view in FIG. 4;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semi-open deck type cylinder block, 2 ... Cylinder bore, 3 ... Cylinder liner, 4 ... Cylinder block outer wall, 5 ... Water jacket, 6 ... Rib as connection part, 7 ... Head bolt hole, 7a ... Counter bore part, 7
b: female thread, 7c: boundary surface, 8: cooling water passage, 9: opening, 10: cylinder head

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) F02F 1/16 F02F 1/16 Z

Claims (3)

[Claims] 1. A plurality of cylinder liners are integrated at a partition wall, and a water jacket is formed between the cylinder liner and an outer wall of a cylinder block, and a portion above the cylinder liner and the outer wall of the cylinder block are partially formed. In the semi-open deck type cylinder block connected to the cylinder block, a connection portion is formed between a partition wall portion between two adjacent cylinder bores and an outer wall of the cylinder block, and a cylinder on a top surface of the connection portion or an extension of the partition wall portion. A semi-open deck type cylinder block in which an opening of a cooling water passage is formed on a top surface of an outer wall of the block, and the cooling water passage extends from the opening through the inside of the partition and reaches the water jacket. 2. The semi-open deck type cylinder block according to claim 1, wherein a top surface of the connecting portion is formed on the same plane as a top surface of an outer wall of the cylinder block. 3. The semi-open deck type cylinder block according to claim 1, wherein a counterbore depth of a head bolt hole formed on an upper surface of the semi-open deck type cylinder block, into which a head bolt is screwed. A semi-open deck type cylinder block having an intermediate position with respect to the height of the connecting portion.