JP3165910B2 - Metal gasket - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal gasket interposed between mating surfaces of a cylinder block and a cylinder head of an internal combustion engine, which maintains a wedge effect of a grommet surrounding a combustion chamber hole of the metal gasket. For a metal gasket made for this purpose.

[0002]

2. Description of the Related Art FIG . 2 is a partial sectional view showing a conventional metal gasket inserted between a cylinder block and a cylinder head.

[0003] The metal gasket is made of a hard elastic substrate 2.
0 and the soft auxiliary substrate 21 are overlapped, and the elastic substrate 20
Is formed with a combustion chamber hole 22 larger than the combustion chamber hole 26 of the auxiliary substrate 21, and a grommet 23 is fitted around the combustion chamber hole 26 of the auxiliary substrate 21.

Further, the elastic substrate 20 and the auxiliary substrate 21 have step beads 20a around and around the combustion chamber 25, respectively.
20b, 21a and 21b are formed, and mainly the elastic substrate 20 is formed.
The bead load is exerted by the step beads 20a and 20b.

[0005] Grommet 2 of such a metal gasket
3 has a total thickness of two elastic substrates 20 and an auxiliary substrate 21.
Is greater than the combined thickness.

Accordingly, when the cylinder block 10 and the cylinder head 11 are fastened by bolts, the loads F1, F2 larger than the loads f1, f2, f3, f4 of the step beads act on the grommet 23 to exert a wedge effect. According to the change in the gap between the cylinder block 10 and the cylinder head 11, it is possible to prevent combustion gas from flowing through.

Further, both sides of the elastic substrate 20 and the auxiliary substrate 2
A rubber coating 24 is applied to the outer surface of 1 and the outer surface of the grommet 23. With such a rubber coating 24,
Roughness existing on the metal surfaces of the cylinder block 10 and the cylinder head 11 is absorbed, or roughness of the metal surface between the elastic substrate 20 and the auxiliary substrate 21 is absorbed.

[0008]

However, the cylinder block 10 and the cylinder head 11 are hit by a gas explosion generated in the combustion chamber 25, which continuously expands and contracts the gap between them.

At this time, the grommet 2 having the largest load is used.
When the upper and lower surfaces of the grommet 3 are hit, the rubber coating 24 of the grommet 23 is crushed and thinned, so that the above-described roughening of the metal surfaces of the cylinder block 10 and the cylinder head 11 cannot be absorbed. There is a problem that the combustion gas passes through the portion.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide a metal gasket capable of maintaining a wedge effect of a grommet surrounding a periphery of a combustion chamber hole of the metal gasket. I do.

[0011]

Means for Solving the Problems] metal gasket of the present invention to solve the aforementioned problem, in the metal gasket interposed in the mating surface of the cylinder block and the cylinder head, a combustion chamber of an auxiliary substrate made of a hard metal plate Mo around the hole
While providing a grommet coated with a ribden coating,
Harden the auxiliary substrate with a gap around the outer periphery of the met.
An elastic substrate made of a metal plate is polymerized, and the auxiliary substrate and the
Rubber coating on the outer and inner surfaces of the rigid substrate
The total thickness of the grommet forming part is equal to the auxiliary substrate.
Greater than the total thickness of the elastic substrate and the elastic substrate
Step surrounding a combustion chamber hole formed in a plate and the auxiliary substrate
The beads have gaps between each other .

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, the metal gasket of this embodiment has an auxiliary substrate 2 and an elastic substrate 3 which is thicker than the auxiliary substrate 2.
In addition, a combustion chamber hole 4 larger than the combustion chamber hole 6 of the auxiliary substrate 2 is formed in the elastic substrate 3, and a grommet 5 is fitted around the combustion chamber hole 6 of the auxiliary substrate 2.

In the metal gasket, the auxiliary beads 2a and 2b, which are formed by contacting the auxiliary substrate 2 and the elastic substrate 3 with each other around the combustion chamber 14 of the cylinder block 10 and in the vicinity of the outer periphery thereof, are bent in steps. 3a and 3b are formed, and the auxiliary substrate 2 is bent downward in the vicinity of the inner periphery of the combustion chamber hole 4 of the elastic substrate 3.

In such a metal gasket, the overall thickness of the grommet 5 closest to the combustion chamber 14 is larger than the thickness of the two substrates 2 and 3, and the step beads 2a, 2b, 3a, 3b load f1, f2, f
3, the loads F1 and F2 larger than f4 are exerted, and a wedge effect for filling a maximum gap near the combustion chamber 14 generated when the cylinder head 11 and the cylinder block 10 are bolted can be exhibited.

Further, in this metal gasket, a molybdenum coating 8 having a thickness of 15 μm or less is provided on the outer surface of the grommet 5, and a rubber having a thickness of 15 μm or more is provided on both surfaces of the elastic substrate 3 and the outer surface of the auxiliary substrate 2. A coating 9 is applied.

In order to apply such a coating, the elastic substrate 3
In the case of the auxiliary substrate 2, the rubber coating 9 is applied to the entire surface of one side of the auxiliary substrate 2, and then the water jet is applied only around the combustion chamber hole 6 of the substrate 2. The rubber coating 9 is partially peeled off, and the grommet 5 provided with the molybdenum coating 8 is fitted around the peeled combustion chamber hole 6 in a U-shaped cross section.

In such a metal gasket, the molybdenum coating 8 on the upper and lower surfaces of the grommet 5 contacts the upper and lower surfaces of the cylinder block 10 and the cylinder head 11, and the rubber coating 9 on the upper surface of the auxiliary substrate 2 is formed on the lower surface of the cylinder head 11. And the upper surface of the rubber coating 9 of the elastic substrate 3 is
The lower surface of the rubber coating 9 of the elastic substrate 3 contacts the upper surface of the cylinder block 10.

Therefore, the molybdenum coating 8 applied to the outer surface of the grommet 5 is much harder than the rubber coating 9, and the molybdenum coating 8 includes the cylinder block 10 and the cylinder head 1.
Even if a load of 1 is applied, the wrinkle effect of the grommet 5 can be favorably maintained without being crushed unlike the conventional rubber coating.

Although the molybdenum coating 8 of the grommet 5 cannot absorb the roughness of the metal like the rubber coating 9 does, even if there is a minute blow-through, it can be supported by the bead load on the outer periphery. The applied rubber coating 9 can prevent blow-through of combustion gas or the like in response to a change in the gap between the cylinder block 10 and the cylinder head 11.

Further, in this metal gasket ,
Similarly to the case where the elastic substrate 3 is formed of a hard metal plate, the auxiliary substrate 2 is also formed of a hard metal plate. Further, in the step beads 2a and 3a on the combustion chamber 14 side, a gap is formed between the elastic substrate 3 and the auxiliary substrate 2. 17, the two substrates 2 and 3 are configured so as to be two sheets.

With such a configuration, independent bead loads can be applied to the step beads 2a, 2b, 3a, 3b of the elastic substrate 3 and the auxiliary substrate 2.

That is, since the elastic substrate 3 and the auxiliary substrate 2 are both formed of a hard metal plate, an independent bead load is generated on the step beads 2a, 2b, 3a, 3b of the substrates 2, 3, but the cylinder load is increased. By fastening the block 10 and the cylinder head 11 with bolts, first, a bead load acts on the step beads 2a, 2b of the thin auxiliary substrate 2 having a small bead load, and then the elastic substrate 3 having a strong bead load.
A stepwise load that a bead load also acts on the step beads 3a and 3b.

Accordingly, the two substrates 2 and 3 are formed of an elastic metal plate, and the step beads 2 a and 2
b, the bead load can be made smaller than that in which the molybdenum coating 8 is formed, and
The wedge effect by the unit 5 can be surely exhibited.
Becomes

Further, in the metal gasket of the above embodiment, water holes 13 corresponding to the water passages 12 of the cylinder block 10 and the cylinder head 11 are provided.

[0026]

As described above, in the metal gasket of the present invention, the grommet closest to the combustion chamber is formed to the maximum thickness, and the outer surface of the grommet is coated with a hard molybdenum coating. Therefore, even if a maximum load is applied to the grommet, the molybdenum film does not collapse, and the film thickness can be maintained.
The wedge effect that fills the maximum gap on the combustion chamber side generated when the cylinder block and the cylinder head are bolted together can be maintained for a long time.

Since the rubber coating is applied to both sides of the portion other than the grommet, it is possible to absorb the roughness of the metal and to prevent the combustion gas from flowing through.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing a metal gasket according to the present invention.
It is .

FIG. 2 is a partial cross-sectional view of a conventional metal gasket .

[Explanation of symbols]

 2: auxiliary substrate 3: elastic substrate 4: combustion chamber hole of elastic substrate 5: grommet 6: combustion chamber hole 8: molybdenum coating 9: rubber coating

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16J 15/08 F02F 11/00

Claims (1)

(57) [Claims] 1. A metal gasket inserted between mating surfaces of a cylinder block and a cylinder head, wherein a hard metal plate
Molybdenum coating around the combustion chamber holes of the auxiliary substrate made of
The grommet is provided with a gap around the grommet.
The auxiliary substrate is made of a hard metal plate
The substrate is superimposed and the auxiliary substrate and the outer surface of the hard substrate and
Rubber coating on the inner surface and the grommet
The total thickness of the forming portion is equal to the total thickness of the auxiliary substrate and the elastic substrate.
Greater than the total thickness, the elastic substrate and the auxiliary substrate
Step beads surrounding the combustion chamber holes formed in
Metal gasket and having a.