JP2932356B2 - 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 in which the thickness of a metal gasket inserted into a mating surface of a cylinder head and a cylinder block of an internal combustion engine is reduced.

[0002]

2. Description of the Related Art As shown in FIG. 4, an inner periphery of a combustion chamber hole of a metal gasket 23 inserted in a mating surface of a cylinder head 24 and a cylinder block 25 of an internal combustion engine has a combustion chamber hole 27 of the internal combustion engine. Clevis volume 20 is formed around the combustion chamber hole 27 side of the mating surface. And the metal gasket 23
The clevis volume 20 increases as the thickness of the clevis increases,
The combustion effect of the combustion gas is hindered, the fuel efficiency and the quality of the exhaust gas are reduced, and especially the value of the hydrocarbon tends to increase.

Accordingly, in recent years, there has been a tendency to reduce the adverse effects of the clevis volume 20 by forming a thin gasket 23 in which a hard thin plate 21 and a soft thin plate 22 are combined as shown in FIG. Was.

[0004]

However, such a thin gasket 23 is inserted into a mating surface 26 between a cylinder head 24 made of aluminum casting and a cylinder block 25 made of cast iron casting as shown in FIG. Then, the thermal expansion coefficients E1 and E2 of the two when cooling and combustion are repeated
, A movement phenomenon (a displacement of the relative positions of the opposed surfaces 24a, 25a) occurs between the opposed surfaces 24a, 25a of the cylinder head 24 and the cylinder block 25.

For this reason, in the thin gasket 23 as described above, squeezing due to the difference in thermal expansion between the cylinder head 24 and the cylinder block 25 is concentrated on the soft substrate 22, and I get up,
There is a problem that the protrusion may extend to the combustion chamber hole 27 side.

The present invention reduces the thickness of a metal gasket inserted into the mating surface between a cylinder head and a cylinder block of an internal combustion engine and reduces the thickness of the mating surface caused by the difference in the coefficient of thermal expansion between the cylinder head and the cylinder block. It is an object of the present invention to provide a metal gasket that is not affected by a movement phenomenon.

[0007]

In order to achieve the above object, a metal gasket according to the present invention is formed by combining a first substrate and a second substrate, and the first substrate and the second substrate are combined. The metal gasket is formed from a hard metal substrate to minimize the total thickness of the gasket as much as possible, and is not affected by the mating surface movement phenomenon caused by the difference in the coefficient of thermal expansion between the cylinder head and the cylinder block.

[0008] A bromette, which forms a primary seal of the combustion gas and functions as a stopper for preventing the cylinder head and the cylinder block from being hit by both sides, is fitted around the combustion chamber hole formed in the first substrate. At the same time, a step bead is provided on the outer periphery of the chain ridge, and a step bead is also provided on the second substrate superimposed on the first substrate so as to form a secondary seal of the combustion gas.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A metal gasket according to the present invention is a metal gasket for an internal combustion engine which is inserted into a mating surface of a cylinder head and a cylinder block made of materials having different coefficients of thermal expansion . Form on one substrate
The grommet is fitted around the perforated combustion chamber hole,
When a step is formed near the outer periphery of the grommet on one substrate,
In addition, the combustion formed on the second substrate made of a hard metal substrate
Position the inner periphery of the chamber hole at the outer periphery of the step of the first substrate.
By polymerizing the second substrate on the first substrate
The inner circumference of the combustion chamber hole of the second substrate is
With a gap to the outer circumference, the first substrate and the
A step bead surrounding the combustion chamber hole is formed on the second substrate.
Formed in the same step direction with a gap between them, these
The first substrate and the second substrate are stacked so that they can move with respect to each other.
It has been combined.

Also, the cooling water formed on the first substrate may be used.
While the first substrate is formed flat around the hole,
The second substrate has a step bead around the cooling water hole.
The configuration provided may be provided .

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Further, the total thickness of said first substrate and the grommet may be configured to be thicker than the total thickness of the first substrate and the second substrate.

Furthermore, the first substrate and the grommet seal member to the outer surface is coated, the second substrate may have a configuration in sealing material on both sides are coated.

[0014]

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

FIG. 1 is a sectional view of a metal gasket according to the present invention .

In FIG. 1, a first substrate 1 and a second substrate 2
Is formed from a hard metal substrate such as SUS301.

The first substrate 1 has a combustion chamber hole 3a surrounding the combustion chamber hole 14 of the cylinder block 13, and a grommet 4 made of a soft plate fits around the combustion chamber hole 3a. Have been. The grommet 4 functions as a stopper for preventing hitting between both surfaces of the cylinder head 12 and the cylinder block 13, and can form a primary seal of the combustion gas.

A step 8 having a height slightly smaller than the thickness of the second substrate 2 is provided at the outer peripheral position of the grommet 4 around the hole 3a for the combustion chamber of the first substrate 1. The center of each of the total thickness T1 of the one substrate 1 and the grommet 4 and the center of the total thickness T2 of the first substrate 1 and the second substrate 2 are matched.

Further, a flat surface 1a is formed on the outer periphery of the step 8.
A step bead 6 is formed through the hole, and this step bead 6 forms a secondary seal of the combustion gas.

The first substrate 1 is provided with a cooling water hole 5a corresponding to the position of the cooling water passage 15, and a surrounding water seal portion is formed on a flat surface 7a.

On the outer periphery of the step 8 of the first substrate 1, the second substrate 2
Positioning the inner periphery of the formed combustion chamber hole 3b, the first base
The holes 3b for the combustion chamber of the second substrate 2 are superimposed on the plate 1
Has a gap D with respect to the outer circumference of the grommet 4
It is being done. That is, the combustion chamber hole 3b of the second substrate 2 has an inner diameter larger than the outer circumference of the grommet 4, and the first substrate 1
In a state where a gap D is provided between the outer periphery of the grommet 4 and the combustion chamber hole 3b of the second substrate 2, the inner peripheral flat surface 2a of the second substrate 2 Are superimposed on the flat surface 1a of the first substrate 1.

The second substrate 2 is also provided with a step bead 9 similar to the first substrate 1. However, in this embodiment, the step bead 6 of the first substrate 1 and the step bead of the second substrate 2
The bead 9 and the bead 9 are formed in the same step direction.
A gap Z is provided between the step beads 6 and 9 of FIG.
The second substrate 2 is overlapped with the second substrate 2 in a movable state.
You .

If there is no gap Z between the step beads 6 and 9 and they match each other, the spring constant of this portion becomes the sum of the spring beads of the step beads 6 and 9 and the resilient force is too strong. On the other hand, since the step bead 6 of the first substrate 1 and the step bead 9 of the second substrate 2 are separated from each other by the gap Z, the step beads 6, 9
Exerts a spring constant, and the amount of bending at this portion is the same as the amount of bending of the step beads 6 and 9.

A step bead 10 functioning as a cooling water seal bead is provided around the cooling water hole 5b of the second substrate 2.
Are provided, and a flat surface 2b is formed on the outer periphery thereof.

The step bead 9 of the second substrate 2 as described above
However, when the cylinder head and the cylinder block are pressed and flexed at the time of tightening and repeated explosions, the deformation amount of the step beat 9 is determined by a gap provided between the outer periphery of the grommet 4 and the second substrate 2. D is absorbed.

Total thickness T of first substrate 1 and grommet 4
1 is thicker than the total thickness T2 of the first substrate 1 and the second substrate 2, and is pressed against the cylinder head 12 and the cylinder block 13 by the bolt axial force at the time of tightening so that the cylinder substrate 12 and the cylinder block 13 come into close contact with each other. In addition to serving as a stopper against repeated hits of the cylinder head 12 and the cylinder block 13 on both surfaces, it also functions as a primary seal for preventing combustion gas from flowing through the combustion chamber holes.

The step beads 6, 9 provided outside the grommet 4 functioning as the stopper function as a secondary seal.

Further, the first substrate 1 and the grommet 4 are coated on one side with a sealing material 11 coated on the outside, and the second substrate 2 is coated on both surfaces with a sealing material on both surfaces.
The contact between the first substrate 1, the second substrate 2, and the grommet 4 and the familiarity of the contact between the first substrate 1, the second substrate 2, the grommet 4, and the cylinder head or the cylinder block are improved, and a sealing effect is obtained. Can be further improved.

In the metal gasket of this embodiment, for example, when this metal gasket is inserted between the mating surfaces of an aluminum cylinder head and a cast cylinder block,
Form in stainless steel, both hard and first substrate 1 and the second substrate 2
And the first substrate 1 and the second substrate 2 have combustion chamber holes.
Step beads 6 and 9 surrounding 14 are the same with a gap Z
And the first substrate 1 and the second substrate
2 are superimposed on each other in a movable state.
The heat between the cylinder head 12 and the cylinder block 13
Even when the mating surface movement phenomenon caused by the difference in expansion coefficient occurs, the mating surfaces of the first substrate 1 and the second substrate 2 can be freely adjusted.
Therefore , the substrates 1 and 2 do not wrinkle.

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[0040]

As described above, in the metal gasket of the present invention, by forming both the first substrate and the second substrate from a hard metal substrate, the total thickness of the entire gasket can be reduced as much as possible. . In addition, the first substrate and the second substrate
Is the same as the step bead surrounding the combustion chamber hole with a gap
These first and second substrates are formed in the direction of the step.
Are superimposed so that they can move with each other ,
Even if the movement behavior of the mating surfaces occurs caused by the difference in thermal expansion coefficient between the cylinder head and the cylinder block, the
Since the one substrate and the second substrate slide freely with respect to each other,
No deformation such as wrinkles occurs between the first substrate and the second substrate.
No.

Further, since the grommet is fitted around the combustion chamber hole formed in the first substrate, the second substrate is superimposed on the first substrate so as not to contact the grommet, Good sealing performance against the blow-by of combustion gas from the combustion chamber hole side can be ensured.

This sealing effect is achieved by making the total thickness of the first substrate and the grommet larger than the total thickness of the first substrate and the second substrate, so that the grommet serves as a stopper. It is possible to make it more reliable.

In the present invention, the first substrate and the second substrate
All substrates are formed from hard metal substrates
The metal inserted between the cylinder head and cylinder block
It is required to center the metal gasket. In the present invention
In this case, a step is formed near the outer periphery of the grommet on the first substrate.
And a second substrate on the outer periphery of the step of the first substrate.
Position the inner periphery of the formed combustion chamber hole and place it on the first substrate.
Because of polymerization, the first substrate at the position where the grommet is provided
And the sum of the positions where the first substrate and the second substrate are superimposed
It is easy to match the center of the thickness .

Further, in the present invention, the fuel of the second substrate
The inner circumference of the firing chamber hole has a gap with the outer circumference of the grommet
Inserted between the cylinder head and cylinder block
The first substrate of the metal gasket of the present invention
And the center of the metal gasket is easy to come out .

Further, the outer surfaces of the first substrate and the grommet are coated with a sealing material, and the both surfaces of the second substrate are coated with a sealing material, so that the members can be easily fitted to the cylinder head and the cylinder block and compressed. The sealing performance at the time can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a metal gasket according to the present invention .

FIG . 2 is a view showing a combination of a cylinder head and a cylinder block;
It is sectional drawing of the circumference | surroundings of a fitting surface .

FIG . 3 is a sectional view of a conventional metal gasket .

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... 1st board | substrate 2 ... 2nd board | substrate 3a ... Hole for combustion chamber of 1st board 3b ... Hole for combustion chamber of 2nd board 4 ... Grommet 5a ... Hole for cooling water of 1st board 5b ... Cooling of 2nd board | substrate Water hole 6 ... Step bead around combustion chamber hole of first substrate 7a ... Flat surface around outer periphery of cooling water hole of first substrate 7b ... Step bead around cooling water hole of first substrate 8 ... Step bead of first substrate 9 Step bead around hole for combustion chamber of second substrate 10 Step bead around hole for cooling water of second substrate 11 Seal material 12 Cylinder head 13 Cylinder block 14 Combustion Chamber hole 15: cooling water passage D: gap between outer periphery of grommet and inner periphery of second substrate Z: gap between step beads of first substrate and second substrate T1: total thickness of first substrate and grommet T2 ... Total thickness of first substrate and second substrate

Claims (4)

(57) [Claims] 1. A metal gasket for an internal combustion engine inserted into a mating surface of a cylinder head and a cylinder block made of materials having different coefficients of thermal expansion, the metal gasket being used for a combustion chamber formed on a first substrate made of a hard metal substrate.
A grommet is fitted around the hole, and the grommet of the first substrate is
A step is formed near the outer periphery of the
The inner circumference of the combustion chamber hole formed in the second substrate
The second substrate is positioned on the outer periphery of the step of the first substrate.
The second substrate is formed by superimposing a substrate on the first substrate.
The inner circumference of the combustion chamber hole is spaced from the outer circumference of the grommet.
While having a space between the first substrate and the second substrate
Step beads surrounding the combustion chamber holes are spaced from each other.
The first substrate and the second substrate are formed in the same step direction.
A metal gasket, wherein two substrates are overlapped so as to be movable with respect to each other . 2. A cooling water hole formed in the first substrate.
While the first substrate is formed flat in the
The two substrates are provided with a step bead around the cooling water hole.
Metal gasket according to claim 1, wherein it was. 3. The metal gasket according to claim 1, wherein a total thickness of said first substrate and said grommet is larger than a total thickness of said first substrate and said second substrate. 4. The metal gasket according to claim 1, wherein the first substrate and the grommet are covered with a sealing material on outer surfaces, and the second substrate is coated with a sealing material on both surfaces.