JP3095053B2 - Cylinder head gasket - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a metal cylinder head gasket for an internal combustion engine, and more particularly to a cylinder head gasket with improved bead durability.

[0002]

2. Description of the Related Art Conventionally, in a metal cylinder head gasket of an internal combustion engine, a bore seal is formed only by a full bead formed around a cylinder bore hole of the cylinder head gasket. In order for the full bead only to follow the cylinder head displacement during combustion of the engine,
No. 113368 (FIG. 23 discloses a metal cylinder head gasket in which a full bead is arranged around a cylinder bore and a half bead is arranged around a water hole). And reduce the number of layers (for example, to two), or
As shown in FIG. 4 (1 is a substrate, 2 is a full bead), the height per one substrate is reduced to increase the number of stacked layers (for example, three).

[0003]

However, the conventional metal cylinder head gasket has the following problems.
When the number of stacked layers is small, the deformation and surface pressure of the full bead per substrate are large, and there is a possibility that cracks may occur in the full bead, and there is a problem in durability. When the number of stacked layers is large, the surface pressure is not so large (see FIG. 5), and the cracking of full beads is suppressed, but the increase in the number of substrates leads to an increase in cost. The purpose of the present invention is
An object of the present invention is to provide a cylinder head gasket in which the occurrence of cracks in full beads is suppressed while the number of substrates is kept small (two) and durability is improved.

[0004]

The present invention to achieve the above object is as follows. (1) Composed of two metal substrates,
Each cylinder bore has a cylinder bore hole, bolt hole, and water hole.
A full bead formed to surround the hole;
The cylinder bore is located at a position close to
Side, remove the full bead around all cylinder bore holes.
First half bead formed to be enveloped from the side
And the opposite side of the first half bead across the water hole
And surrounds the first half bead from outside
Having a second half bead formed as described above
Dahead gasket. (2) The two metal substrates are tightened with head bolts.
Before the first half bead and the second half bead
In close contact with each other at the site between
The cylinder head gas according to (1), wherein the water hole is provided.
Sket.

[0005] In the cylinder head gasket of the present invention (1) and (2) , since the full bead and the half bead are arranged around the cylinder bore, the load applied to the cylinder head gasket is distributed to the full bead and the half bead. Therefore, the load applied to the full bead is reduced, and the occurrence of cracks in the full bead is suppressed accordingly, and the durability is improved. For this reason, the number of metal gasket substrates can be reduced, and the cost can be reduced.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A cylinder head gasket according to a preferred embodiment of the present invention will be described with reference to FIGS.
1 and 2 show a cylinder head gasket 11 placed on a cylinder block 10 of an automotive multi-cylinder internal combustion engine.
Shows a part of. Cylinder head gasket 11
Is sandwiched between the cylinder block 10 and a cylinder head (not shown), and is pressed by the cylinder head and the cylinder block when the cylinder head gasket 11 is tightened to the cylinder block 10 by the head bolt.

The cylinder block 10 includes a plurality of cylinder bores 12 arranged in a row in parallel, and a plurality of cylinder bores 12.
The cooling water passage (water jacket) 13 is disposed on both sides of the row and extends in the longitudinal direction of the cylinder block so as to enclose the cylinder bore 12, and a bolt hole into which the cylinder head bolt is screwed. The cylinder head gasket 11 is formed by stacking two metal substrates 15 and 16. Cylinder head gasket 11
Has a cylinder bore hole 17, a bolt hole 14, and a water hole 18. The water hole 18 allows cooling water to flow from the cooling water passage 13 in the cylinder block 10 to the cooling water passage in the cylinder head.

The cylinder head gasket 11 has a full bead 19 formed so as to surround each cylinder bore 17 along each cylinder bore 17, and a full cylinder bore at a position close to the full bead 19 and at a position closer to the cylinder bore than the water hole 18. A half bead 20 formed so as to enclose the full bead 19 around the hole from the outside, and another half bead 21 formed on the opposite side to the half bead 20 with the water hole 18 therebetween and formed so as to surround the half bead 20 from the outside. And Beads 19, 20,
The height of 21 is set so that the height of the bead per sheet is increased and only two substrates can follow the cylinder head displacement during engine combustion.

The full bead 19 and the half bead 20 on the side close to the full bead 19 form 1.5 beads (full bead 1.0 , half bead 0.5) except for the portion between the cylinder bores. Inside the full bead 19, there is a space between the two substrates 15, 16 before the cylinder head is fastened to the cylinder block by the head bolt. Even between the full bead 19 and the half bead 20 close to the full bead 19, there is a space between the two substrates 15 and 16 before the cylinder head is tightened to the cylinder block by the head bolt. In the portion between the two half beads 20 and 21, two substrates 1
5 and 16 are in close contact with each other before the cylinder head is tightened to the cylinder block by the head bolt, and a water hole 18 is formed in the closely contacted portion. This water hole 1
8 communicates with the cooling water passage 13. The two half beads 20 and 21 correspond to a shape obtained by extending a conventional half bead formed around a water hole of Japanese Utility Model Laid-Open No. 4-113368 so as to extend around a cylinder bore hole .

Next, the operation will be described. Cylinder bore 1
2 is sealed by a full bead 19 and the water hole 18 is
Sealed with strip half beads 20,21. When the cylinder head is fastened to the cylinder block 10 by the head bolt, the cylinder head gasket 11 is pressed by the cylinder head and the cylinder block 10.
The surface pressure generated in the cylinder head gasket 11 by this pressing load is as shown in FIG.
Dispersed in half bead 20. As a result, as can be seen from the comparison between FIG. 3 and FIG. Is smaller than the surface pressure of the full bead portion of the conventional two-layer cylinder head gasket). This is because the load is received only by the full bead in the related art, but is received by the full bead 19 and the half bead 20 in the embodiment of the present invention.
This is because the burden on the user is reduced. In addition, the load of full beads has been successfully reduced with the two substrates being stacked instead of the three substrates. As a result, the occurrence of cracks at the 19 full beads is suppressed, and the cylinder head gasket 11
Is improved in durability. In addition, the durability can be improved without essentially increasing the cost as compared with the conventional two-layered substrate. Further, as compared with the conventional three-layered substrate, the cost can be reduced by the reduction in the number of substrates.

The engine cooling water is a half bead 20.
Since the cooling water does not enter the full bead 19, stress corrosion cracking of the full bead 19 is suppressed, and from that point, the durability of the cylinder head gasket 11 is improved. When the cylinder head and the cylinder block are fastened, a load is applied to the bead portion (near the combustion chamber), so that the cylinder bore 12 is at least deformed. However, in the embodiment of the present invention, since the load is distributed to the full bead 19 and the half bead 20, the deformation of the cylinder bore 12, which is strongly affected by the load applied to the full bead 19, is reduced. As a result, the frictional force between the inner surface of the cylinder bore 12 and the piston ring can be reduced, and as a result,
The fuel consumption of the engine can be reduced.

[0012]

According to the first and second aspects of the present invention, the cylinder head gasket is provided.
According to preparative, since the half bead around the water hole was meditating around the cylinder bore hole, will be arranged and the full bead and a half bead around the cylinder bore hole, the load applied to the cylinder head gasket is distributed to the full bead and a half bead, the full beads , The occurrence of cracks in full beads is suppressed accordingly, and the durability is improved. In addition, the number of metal gasket substrates can be reduced, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a partial plan view of a cylinder block on which a cylinder head gasket according to one embodiment of the present invention is mounted.

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

FIG. 3 is a surface pressure distribution diagram of the cylinder head gasket of FIG. 1 when the cylinder head is fastened.

FIG. 4 is a partial cross-sectional view showing the vicinity of a full bead of a conventional cylinder head gasket having three stacked substrates.

FIG. 5 is a surface pressure distribution diagram of the cylinder head gasket of FIG. 4 when the cylinder head is fastened.

[Explanation of symbols]

 Reference Signs List 10 Cylinder block 11 Cylinder head gasket 12 Cylinder bore 13 Cooling water passage 15, 16 Board 17 Cylinder bore hole 18 Water hole 19 Full bead 20, 21 Half bead

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F16J 15/00-15/14 F02F 11/00

Claims (2)

(57) [Claims] 1. A method comprising the steps of laminating two metal substrates.
Cylinder holes, bolt holes, and water holes.
A full bead formed to surround the dovetail hole;
The syringe is located close to the ruby and from the water hole.
At the position of the dobore side, the full bee around all cylinder bore holes
The first half bead formed so as to enclose the
Bead and the first half bead across the water hole.
Forming the first half bead from the outside
A second half bead formed so as to surround it.
Linda head gasket. 2. The method according to claim 1, wherein the two metal substrates are provided with a head bolt.
Before tightening the first half bead and the second hard bead,
At the portion between the beads, it adheres to each other,
The cylinder according to claim 1, wherein the water hole is provided at a position.
Head gasket.