JPH0414676Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a metal gasket used for sealing the joint surface between a cylinder head and a cylinder block of an internal combustion engine, particularly a multi-cylinder internal combustion engine. The present invention relates to a metal gasket equipped with a grommet shim that exerts a surface pressure adjustment function on a bead and a high-temperature gas shielding function.

(Prior art) Modern internal combustion engines tend to be lighter in weight as well as higher output and higher temperatures.Instead of conventional castings, both the cylinder head and cylinder block are made of aluminum, or only the cylinder head is made of aluminum. It is made of aluminum, but due to the use of such a low-rigidity material, the rigidity of the cylinder head and cylinder block tends to decrease during operation, and the relative displacement between the cylinder head and cylinder block tends to increase. It is in.

For this reason, there is a need for a gasket that can sufficiently respond to repeated fluctuations in gas pressure, heat generation, and vibration during an explosion, and that can maintain sealing performance over a long period of time. An adjustment plate is interposed between two bead substrates having outwardly directed beads surrounding the opening, and the diameter of the cylinder bore opening of the adjustment plate is made smaller than that of the bead substrate, thereby creating an extended state. A laminated metal gasket has been invented and is known in which a grommet having a thickness greater than the thickness of the bead portion at the time of pressure fastening is attached to the circumferential edge thereof.

(Problem to be solved by the invention) However, according to the structure of the above-mentioned known metal gasket, the shim effect can only be expected by a small difference between the thickness of the grommet and the thickness of the bead substrate. It cannot be a fundamental countermeasure against the high stress and high load stress amplitude that occur in the bead around the bore opening, and it also has the disadvantage that the bead may crack or sag, making it impossible to maintain sealing performance. When installing the shim, it is necessary to form a gap between the end face of the bead board and the end face of the shim in consideration of thermal expansion and deformation of the bead board, and this method cannot be applied when the gap between the cylinder bore openings is wide. However, in a cylinder with a narrow space between cylinder bore openings, sufficient sealing effect and durability could not be expected, and there was a problem to be solved in that it was difficult to apply.

(Means for Solving the Problems) The structure of the metal gasket according to the present invention is as follows.

That is, two beaded substrates 3 having inwardly facing beads 4, 4 formed in a contour shape along the periphery and outer periphery of the parallel cylinder bore opening A and other openings, and having surface treatments 5, 5 applied to both surfaces. , 3 are arranged on both sides of the adjustment plate 2, and a grommet shim 6 is attached to the cylinder bore opening A of the adjustment plate 2.
This metal gasket is characterized in that it is mounted so as to be sandwiched between the edges of the cylinder bore openings A of the bead substrates 3, 3 when the gaskets are press-fastened.

(Example) The structure of a metal gasket according to the present invention will be explained based on an example.

FIG. 1 is a plan view of a metal gasket 1 showing an embodiment of the present invention, in which cylinder bore openings A are arranged in parallel at the center of the width, and cooling water, oil, A number of openings for other bolts are drilled.

Beads 4 are formed in contours along the periphery of the opening A and other openings of the bead substrate 3, and along the outer periphery B at locations indicated by dashed lines in FIG.

As shown in FIG. 2, the cross-sectional structure of the metal gasket 1 includes bead substrates 3, 3 arranged on both sides of the adjustment plate 2, two bead 4 along the periphery of the cylinder bore opening A, and a bead 4 arranged along the periphery of the cylinder bore opening A, A single bead 4 is formed on the outer circumferential edge and the outer circumferential edge B so that the bead 4 bulges inward to form a contour and is arranged symmetrically with respect to the adjustment plate 2.

A sealing film is formed on both surfaces of the bead substrates 3, 3 by surface treatment 5, 5.

Furthermore, as shown in FIG. 2, a grommet shim 6 at the cylinder bore opening A of the adjustment plate 2 is inserted into the cylinder bore opening A of the bead base plate 3 when the cylinder bore opening A of the adjustment plate 2 is pressed. It is mounted so as to be sandwiched between the edges of the opening A, and flanges 7, 7 extending toward the beads 4, 4 are formed, respectively.

The grommet shim 6 sandwiched in the cylinder bore opening A of the adjustment plate 2 is made of stainless steel.
SUS304 is used, and the hardness HV is in the range of 180 to 200.
It has a lower hardness than HV350 to HV450, and can be easily attached to the adjustment plate 2.

To give a specific example, the thickness of the bead substrates 3, 3 is
0.3 mm, the height of the bead 4 is 0.2 mm, the thickness of the grommet shim 6 is 0.1 mm, and the width of the flange parts 7, 7 is 1.0 mm.
0.1 mm is the space in which the corresponding bead 4 can be deformed.

In this case, the thickness of the bead substrate 3, the bead 4
The height and shape of the grommet shim 6 and the plate thickness of the flange portions 7, 7 of the grommet shim 6 may be appropriately selected depending on the usage conditions.

(Operation and effect of the invention) The metal gasket according to the invention has inwardly directed beads 4, 4 formed in a contour along the periphery and outer periphery of the parallel cylinder bore openings A and other openings, and is surface-treated on both sides. The two bead substrates 3, 3 provided with 5, 5 are arranged on both sides of the adjustment plate 2, and the cylinder bore opening A of the adjustment plate 2 is
In the metal gasket with the grommet shim 6 attached, the cylinder bore opening A of the adjustment plate 2
Since the grommet shims 6 are mounted so that they are sandwiched between the edges of the cylinder bore openings A of the bead substrates 3 during press-fastening, excessive deformation of the bead due to the compressive load applied to the bead substrates on both sides is prevented. , can be suppressed by the flange surface of the grommet shim, lowering the maximum load stress of the bead,
Not only can the load stress width be reduced to exert a surface pressure adjustment effect, but at the same time, the shielding effect of the grommet shim located inside the bead effectively prevents high-temperature gas from coming into direct contact with the bead. Although it has an extremely simple structure, a metal gasket with excellent sealing performance and durability can be obtained.

In addition, since the thickness of the grommet is configured to act as a shim effect, it has sufficient durability against the high stress and high load stress amplitude generated in the bead around the cylinder bore opening, and prevents cracks and deformation in the bead. It is possible to maintain excellent sealing performance without causing this.

Furthermore, the cylinder bore opening A of the adjustment plate 2
Since the grommet shims 6 were installed so that they were sandwiched between the edges of the cylinder bore openings A of the bead substrates 3, 3 during press-fastening, thermal expansion and deformation of the bead substrates were taken into consideration when installing the shims. Therefore, there is no need to form a gap between the end face of the bead substrate and the end face of the shim as in the conventional case, so when the gap between the cylinder bore openings is wide,
No matter where it is applied, it can exhibit sufficient sealing effect and durability.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a metal gasket according to the present invention, and FIG. 2 is an enlarged end view taken along the line X--X in FIG. 1...Metal gasket, 2...Adjustment plate, 3...
Bead substrate, 4...Bead, 5...Surface treatment, 6
... Grommet shim, 7... Flange part, A...
Cylinder bore opening, B...Outer periphery.

Claims (1)

[Scope of utility model registration request] Inwardly directed beads 4, 4 are formed in a contour shape along the peripheral edge and outer peripheral edge of the cylinder bore openings A and other openings that are parallel to each other, and surface treatments 5, 5 are applied to both surfaces.
In the metal gasket, two bead substrates 3, 3 having been subjected to A metal gasket characterized in that a grommet shim 6 in a portion of the cylinder bore opening A is mounted so as to be sandwiched between the edges of the cylinder bore opening A of the bead substrates 3, 3 when press-fastening.