JPH09268945A - Crank shaft supporting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve rigidity of a crank shaft receiving part, and prevent deformation by arranging a block side sleeve groove having a diameter larger than that of a crank shaft receiving surface and a cap side sleeve groove on a cylinder block and a bearing cap, and arranging iron made sleeves respectively. SOLUTION: A crank shaft 8 is supported by bearing surfaces 10, 12 of a block side and a cap side formed in a semicircular shape on a cylinder block 4 and a bearing cap 6. In this case, sleeve grooves 14, 16 having a diameter larger than that of each crank shaft receiving surfaces 10, 12 are formed on the cylinder block 4 and the bearing cap 6, and sleeves 18 are fit to the sleeve grooves 14, 16 by means of press-in. The sleeve 18 is formed of iron of cast iron and the like, it is formed of first and second sleeves 20, 22 which are divided into two parts in a semicircular shape, fastening force of a fastening bolt 28 is shared by respective sleeves 20, 22, and thereby, it is possible to improve rigidity of laminating surface 26, and also it is possible to suppress deformation of the laminating surface 26 part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crankshaft support structure, and more particularly to a crankshaft support structure capable of improving rigidity of a crank bearing portion.

[0002]

2. Description of the Related Art In some engines, a crankshaft is supported between a cylinder block and a bearing cap.

That is, as shown in FIGS.
In the second aspect, the cylinder block 104 is provided with a semicircular block side crank bearing surface 106, and the bearing cap 108 is provided with a semicircular cap side crank bearing surface 110 corresponding to the block side crank bearing surface 106. A crank shaft 116 is pivotally supported on the block side crank bearing surface 106 and the cap side crank bearing surface 110 via a block side sleeve 112 and a cap side sleeve 114. The block-side sleeve 112 and the cap-side sleeve 114 are cast into the cylinder block 114 and the bearing cap 108, and the cylinder block 1
The joint surface 118 of the bearing 04 and the bearing cap 108 has high rigidity.

The sleeve splitting surface 120 between the block side sleeve 112 and the cap side sleeve 114 is positioned on the same straight line as the mating surface 118 and oriented horizontally.

A bearing cap 108 is attached to the cylinder block 104 with a tightening bolt 122.

Further, as such a crankshaft support structure, Japanese Utility Model Laid-Open No. 56-115543 and Japanese Utility Model Laid-Open 58-58-
It is disclosed in Japanese Patent No. 63339. Actual Kaisho 56-11
Japanese Patent No. 5543 discloses a main bearing mounting structure in which a main bearing cap is attached to a cylinder block to hold a main bearing that supports a crankshaft, and carbon steel is attached to a portion where the outer periphery of the main bearing contacts. It has a cast structure. Japanese Utility Model Application Laid-Open No. Sho 58-63339 discloses an internal combustion engine in which a cylinder block and a bearing cap, which is paired with a bearing housing portion provided in a palk head portion of the cylinder block and supports a crankshaft, are made of a light alloy. In the engine, similarly to the bearing housing, the bearing cap is internally provided with a semi-annular body made of a highly rigid material so as to surround the journal portion of the crankshaft.

[0007]

However, in the conventional crankshaft support structure, the sleeve split surface between the block-side sleeve and the cap-side sleeve is horizontally aligned with the mating surface between the cylinder block and the bearing cap. Since it is oriented in the direction, the rigidity of the mating surface portion is lowered against the bolt tightening force and the explosive load when tightening the tightening bolt, which causes the disadvantage that the mating surface portion is deformed.

[0008]

In order to eliminate the above-mentioned inconvenience, the present invention provides a cylinder block with a semicircular block-side crank bearing surface, and the bearing cap has the block-side crank bearing surface. Correspondingly, a semicircular cap-side crank bearing surface is provided, and a crankshaft support structure for pivotally supporting a crankshaft on the block-side crank bearing surface and the cap-side crank bearing surface,
The cylinder block is provided with a block side sleeve groove having a diameter larger than that of the block side crank bearing surface, and the bearing cap has a diameter larger than that of the cap side crank side bearing surface and corresponds to the block side sleeve groove. A sleeve groove is provided, and an iron-based sleeve is provided in the block-side sleeve groove and the cap-side sleeve groove.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, since the iron sleeve is provided in the block-side sleeve groove and the cap-side sleeve groove, the rigidity of the crank bearing portion is improved at the mating surface portion between the cylinder block and the bearing cap. It is possible to prevent the deformation of this mating surface part, and to suppress the deformation due to the bolt tightening force and the explosion pressure by setting the rigidity of the sleeve. Furthermore, the elastic effect of the sleeve absorbs the vibration at the time of the explosion. Can be made.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; 1 to 5 show an embodiment of the present invention. 1, 2 and 5, 2 is an engine, 4 is, for example, an aluminum cylinder block, and 6 is, for example, an aluminum bearing cap.

A crankshaft 8 is supported between the cylinder block 4 and the bearing cap 6.

The crankshaft 8 is connected to the cylinder block 4
A block side crank bearing surface 10 formed in a semicircular shape with a radius R1 and a cap side bearing surface 12 formed in the bearing cap 6 in a semicircular shape with a radius R1 and corresponding to the block side crank bearing surface 10. Supported by.

The cylinder block 4 has a block-side sleeve groove 14 having a diameter larger than that of the block-side crank bearing surface 10.
Are formed. This block side sleeve groove 14 is
The inner diameter is R2 and the outer diameter is R3.

Further, the bearing cap 6 is formed with a cap side sleeve groove 16 having a diameter larger than that of the cap side crank bearing surface 12 and corresponding to the block side sleeve groove 14.

A sleeve 18 is press-fitted into the block-side sleeve groove 14 and the cap-side sleeve groove 16.

The sleeve 18 is made of an iron-based material such as cast iron, and is divided into two semi-circular annular first and second sleeve bodies 2.
It consists of 0 and 22.

The first sleeve body 20 and the second sleeve body 22 are, as shown in FIGS.
4 is disposed so as to be oriented in a direction substantially perpendicular to the mating surface 26 between the cylinder block 4 and the bearing cap 6.

As shown in FIGS. 2 and 5, the sleeve 18 is provided by press-fitting (indicated by an arrow) into the block-side sleeve groove 14 and the cap-side sleeve groove 16 from the side.

A bearing cap 6 is attached to the cylinder block 4 with a tightening bolt 28.

Next, the operation of this embodiment will be described.

As shown in FIG. 4, when the bolt tightening force at the time of tightening the tightening bolt 28 acts inward, the bolt tightening force can be shared by the first and second sleeves 20 and 22. Therefore, the rigidity of the mating surface 26 can be improved, and the deformation of the mating surface 26 portion can be suppressed.

Further, as shown in FIG. 4, when an explosive load is applied, a force acting outward is applied to the first and second sleeves 20 and 2.
2 can be shared, improving the rigidity of the mating surface 26,
The deformation of the mating surface 26 can be suppressed.

Further, when the engine 2 is in actual operation, the sleeve 18 restrains the crankshaft 8 portion due to the difference in the coefficient of thermal expansion between the iron sleeve 18 and the aluminum cylinder block 4 and the bearing cap 6. Deformation can be suppressed.

Furthermore, by setting the rigidity of the sleeve 18, it is possible to suppress deformation due to bolt tightening force and explosion pressure.

Further, due to the elastic effect of the iron-based sleeve 18, it is possible to absorb the vibration at the time of explosion.

[0026]

As is apparent from the above detailed description, according to the present invention, the cylinder block is provided with the block side sleeve groove having a diameter larger than that of the block side crank bearing surface, and the bearing cap is provided with the cap side crank side bearing surface. By providing a cap-side sleeve groove having a larger diameter than the above and corresponding to the block-side sleeve groove, and providing an iron-based sleeve in the block-side sleeve groove and the cap-side sleeve groove,
It is possible to improve the rigidity of the crank bearing portion at the mating surface portion between the cylinder block and the bearing cap and prevent deformation of this mating surface portion.

Further, by setting the rigidity of the sleeve, it is possible to suppress deformation due to bolt tightening force and explosion pressure.

Further, due to the elastic effect of the sleeve, vibration at the time of explosion can be absorbed.

[Brief description of drawings]

FIG. 1 is a front view of an engine.

FIG. 2 is a bottom view of a cylinder block.

FIG. 3 is a sectional view of a crank bearing portion.

FIG. 4 is a sectional view of a sleeve.

FIG. 5 is a bottom view of a cylinder block.

FIG. 6 is a front view of a conventional engine.

FIG. 7 is a cross-sectional view of a conventional crank bearing portion.

[Explanation of symbols]

 2 Engine 4 Cylinder Block 6 Bearing Cap 8 Crank Shaft 10 Block Side Crank Bearing Surface 12 Cap Side Crank Bearing Surface 14 Block Side Sleeve Groove 16 Cap Side Sleeve Groove 18 Sleeve 20 First Sleeve 22 Second Sleeve 24 Sleeve Split Surface 26 Mating Surface

Claims (2)

[Claims] 1. A cylinder block is provided with a semicircular block side crank bearing surface, and a bearing cap is provided with a semicircular cap side crank bearing surface corresponding to the block side crank bearing surface. In a crankshaft support structure for supporting a crankshaft on a bearing surface and the cap side crank bearing surface, a block side sleeve groove having a diameter larger than that of the block side crank bearing surface is provided in the cylinder block, and the bearing cap is provided. A cap-side sleeve groove having a diameter larger than that of the cap-side crank-side bearing surface and corresponding to the block-side sleeve groove is provided, and an iron-based sleeve is provided in the block-side sleeve groove and the cap-side sleeve groove. Characteristic crank bearing support structure. 2. The sleeve comprises a first and a second sleeve body divided into two semicircular rings, and a sleeve split surface between the first sleeve body and the second sleeve body is the cylinder block and the bearing cap. The crankshaft support structure according to claim 1, wherein the crankshaft support structure is arranged so as to be oriented in a direction substantially perpendicular to a mating surface with the.