JP2552573Y2 - Cylinder block - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder block of an engine.

[0002]

2. Description of the Related Art In an engine cylinder block, a large stress is applied to a spigot portion of a support member in which a main bearing cap is fitted by the main bearing cap pulling a support member of the main bearing portion via a bolt by an explosion load. Occur.

Conventionally, this stress has been reduced by increasing the rigidity of the support member around the spigot portion and suppressing deformation of the spigot portion.

[0004] As a conventional cylinder block for suppressing such deformation around the spigot portion, for example, FIG.
And FIG.

In FIGS. 4 and 6, 1 is a cylinder block,
Reference numeral 2 denotes a plurality of cylinder bores arranged in parallel, in which a reciprocating piston is inserted via a cylinder liner. Reference numeral 3 denotes a skirt portion integrally formed below the cylinder bore 2. Reference numeral 4 denotes a main bearing disposed in the skirt portion 3. Reference numeral 5 denotes a partition-like support member forming the main bearing portion 4, 6 denotes a spigot portion formed on the lower surface of the support member 5, 7 denotes a lower surface of the support member 5 which is fitted into the spigot portion 6 via a bolt 8. A main bearing cap, which is fixed and forms the main bearing portion 4 in cooperation with the support member 5, 9 is a bridge portion connecting the support member 5 and the inside of the skirt portion 3 and a bridge portion for reinforcing the support member 5, 10 is a support member In order to increase the rigidity of the bridge portion 9 and the bridge portion 9, a stiffening member integrally formed on the lower surface of the bridge portion 9 so as to connect the support member 5 and the inner lower end of the skirt portion 3, and 11 is a scar Bolted to the oil pan on a lower surface of part 3, R is a circular arc which is formed on the lower surface of the connection to the support member 5 of the stiffening member 10.

Therefore, in the cylinder block 1 shown in FIG.
As shown in the enlarged view of FIG. 5, the top of the arc R of the stiffening member 10 is connected to the lower end of the support member 5, and in the cylinder block 1 of FIG. 6, as shown in the enlarged view of FIG. 10
Is connected to the side surface of the support member 5 so as to be located above the ceiling surface 6 a of the spigot portion 6.

[0007]

The engine was assembled using the cylinder block 1 shown in FIGS. 4 and 6, and the stress at the corner A of the ceiling of the spigot portion 6 and the arc R of the stiffening member 10 were investigated. As shown in FIG. 8, the relationship between the setting stress and the fluctuating stress was obtained.

That is, the cylinder block 1 shown in FIG.
Then, the stress generated at the corner A of the ceiling of the spigot portion 6 in FIG. 5 is higher than the fatigue limit determined by the inversely proportional relationship between the setting stress and the fluctuating stress. The stress generated in the arc R is low in both the setting stress and the fluctuating stress, and is a value below the fatigue limit.

In the cylinder block 1 shown in FIG.
The stress generated at the corner A of the ceiling of the spigot portion 6 in FIG. 7 is low in both the setting stress and the fluctuating stress, and is below the fatigue limit. The stress generated in the arc R in FIG. Since the fluctuating stress is high, the value exceeds the fatigue limit.

As described above, the support member 5 of the stiffening member 10
The difference between the setting stress and the fluctuating stress occurs depending on the connection position of the stiffening member 10 because the method of dispersing the stress differs depending on the connection position of the stiffening member 10.

Note that the setting stress is a static stress generated when the cylinder block 1 is incorporated into an engine together with other parts, and the fluctuating stress is a maximum stress and a minimum stress generated during operation of the engine. The maximum stress is generated in the explosion process, and the minimum stress is generated in the exhaust process.

In view of the above-mentioned circumstances, the present invention provides a stress generated at a spigot portion provided on a support member of a main bearing portion and a stress generated at a support member side connection portion of a stiffening member connecting a support member and a skirt portion. The purpose of the present invention is to reduce the amount.

[0013]

According to the present invention, a skirt portion is provided below a plurality of cylinder bores arranged in parallel, and a support member of a main bearing portion for supporting a crankshaft is provided in the skirt portion in a plan view. When viewed from above, the cylinder bore is disposed so as to sandwich the cylinder bore and the skirt portion and the support member are connected by a stiffening member. It is located between a position above the lower end of the spigot portion formed above and the ceiling surface.

[0014]

The stress at the corner of the ceiling in the spigot formed on the lower surface of the support member and the stress at the arc formed at the connection portion of the stiffening member on the support member side are both reduced to the fatigue limit or less.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 3 show an embodiment of the present invention.
The same components as those shown in FIGS. 4 to 7 are denoted by the same reference numerals.

The basic structure of the cylinder block 1 in this embodiment is substantially the same as that shown in FIGS.
The way in which the stiffening member 10 is connected to the support member 5 is different from that shown in FIGS.

That is, in the cylinder block of this embodiment, the top of the arc R formed on the lower surface of the connecting portion of the stiffening member 10 to the support member 5 is closer to the lower end of the spigot portion 6 formed on the lower surface of the support member 5. Also from the upper position to the ceiling surface 6
It is located at H until a.

When the engine was assembled using the cylinder block 1 having the above-described structure, and the stress at the corner A of the ceiling of the spigot portion 6 and the arc R of the stiffening member 10 were adjusted, the setting stress as shown in FIG. The relationship of fluctuating stress was obtained.

That is, in the cylinder block 1 shown in FIGS. 1 and 2, the stress generated at the corner A of the ceiling of the spigot portion 6 in FIG. And the arc R in FIG.
, The setting stress and the fluctuating stress are not so high, and are below the fatigue limit. As described above, since the stress at the corner A of the ceiling of the spigot portion 6 and the stress at the arc R of the stiffening member 10 can be reduced, the reliability of the cylinder block 1 is significantly improved.

It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the scope of the present invention.

[0022]

According to the cylinder block of the present invention, the stress at the arcuate portion formed at the ceiling corner of the spigot provided on the lower surface of the support member and at the lower surface of the support member side connection portion of the stiffening member is reduced. It is possible to achieve an excellent effect of being able to do so.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of a cylinder block according to the present invention.

FIG. 2 is a view taken in the direction of arrows II-II in FIG. 1 when a main bearing cap is removed.

FIG. 3 is an enlarged view of a part III in FIG. 1;

FIG. 4 is a longitudinal sectional view of an example of a conventional cylinder block.

FIG. 5 is an enlarged view of a portion V in FIG. 4;

FIG. 6 is a longitudinal sectional view of another example of a conventional cylinder block.

FIG. 7 is an enlarged view of a portion VII in FIG. 6;

8 is a graph showing the relationship between the setting stress and the fluctuating stress at the ceiling corner of the spigot portion of the cylinder block and the arc portion of the stiffening member shown in FIGS. 1, 4, and 6. FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder bore 3 Skirt part 4 Main bearing part 5 Support member 6 Inlay part 6a Ceiling surface 10 Stiffening member R Arc H Between upper part from lower end of inlay part to ceiling surface

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Takao Takahata 3-1, 1-1 Hinodai, Hino-shi, Tokyo Hino Motors, Ltd.

Claims (1)

(57) [Scope of request for utility model registration] 1. A skirt portion is provided below a plurality of cylinder bores arranged in parallel, and a support member of a main bearing portion for supporting a crankshaft is arranged in the skirt portion so as to sandwich the cylinder bore when viewed in plan. In the cylinder block in which the skirt portion and the supporting member are connected by the stiffening member, the top of the arc formed on the lower surface of the connecting portion of the stiffening member to the supporting member is set at the lower end of the spigot portion formed on the lower surface of the supporting member. The cylinder block is also located between the upper position and the ceiling surface.