JPH07133868A - Laminated metal gasket - Google Patents

Abstract

PURPOSE:To increase the restoring amount of a bead on a surface sheet in contact with a joint plane having large strain, and prevent leakage at the joint plane, regarding a metal gasket where a surface sheet having a bead projected for surrounding a hole to be sealed is laminated on both sides of an intermediate sheet. CONSTITUTION:A gasket 1 is formed out of an intermediate sheet 7 having a bent section 8 along the periphery of a hole section to be sealed, such as a combustion chamber hole 2, and elastic metal surface sheets 5 and 6 laminated on both sides of the sheet 7 and having a projected bead 9 or 10 for surrounding the hole section at the outer position of the bent section 8. In addition, the bent section 8 of the sheet 7 is formed in such state as bent toward the surface sheet 5 in contact with a joint plane having larger strain in joint planes clamping the gasket 1. Also, the height of the bead 9 on the sheet 5 is formed to be higher than the bead 10 on the other surface sheet 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated metal gasket used as an engine cylinder head gasket or the like.

[0002]

2. Description of the Related Art Conventionally, FIG. 8 shows around a hole to be sealed such as a hole for a combustion chamber of a cylinder head gasket of an engine or a hole for a liquid passage such as a hole for a cooling water passage and a hole for an oil passage. A laminated metal gasket having such a seal structure is used. That is, the hole 10 to be sealed
On the both sides of the metal intermediate plate 103 having the folded portion 104 at the periphery of 0, convex beads 105 and 106 surrounding the hole portion 100 are provided at positions outside the folded portion 104, and are made of an elastic metal plate. A laminated metal gasket in which face plates 101 and 102 are laminated.

Convex beads 1 of the surface plates 101 and 102
05 and 106 are formed in the same shape with the same height and width, and are provided so as to face each other such that the apex of the bead is in contact with the intermediate plate 103. A seal material layer 107 made of rubber or synthetic resin is provided on at least the outer surface side (both sides in the figure) of the surface plate to compensate for roughness of the joint surface where the gasket is sandwiched. .

In the above seal structure, the intermediate plate 103
Since a thick portion is formed on the periphery of the hole to be sealed by the folded-back portion 104, the thick portion compensates for a gap generated around the hole to be sealed due to the distortion of the joint surface. For example, a bead 105, 106 that seals the periphery of the hole and surrounds the hole on the outer side of the hole forms a seal line when the bead 105, 106 is tightened between the joint surfaces, and the hole 100 to be sealed is double-sealed. To do.

[0005]

The above-mentioned laminated metal gasket is, for example, sandwiched between joint surfaces of an engine cylinder head, a cylinder block, etc., and holes to be sealed on the joint surfaces, such as combustion chambers and cooling water passages. , Seals oil passages, etc., but the two joint surfaces where the gasket is sandwiched are respectively processed strain, strain caused by bolt tightening,
There is strain due to heat or strain due to explosive force, and these strains are not the same between the two joint surfaces due to the difference in material and structure of the two joint surfaces, and the magnitude of the strain between the two joint surfaces is large. There are quite a few differences in size.

Thus, when the laminated metal plate gasket having the above-mentioned sealing structure is mounted between the two joint surfaces having different strains, there is a problem that leakage tends to occur on the joint surface side where the strain is large. . According to the study by the inventors of the present application, this is because, in the double seal structure formed around the hole, the convex bead forming the outer seal has a large amount of distortion on the joint surface side. It is thought that this is due to the fact that the required restoring surface pressure cannot be obtained due to lack of pressure.

The present invention has been made in view of the above points, and the present invention aims to increase the amount of bead restoration on the joint surface side having a large strain and prevent leakage from the joint surface side having a large strain. It is intended.

[0008]

In order to achieve the above object, the laminated metal gasket of the present invention is provided with a folded portion at the periphery of the hole to be sealed. A laminated metal gasket in which a surface plate made of an elastic metal plate provided with a convex bead that surrounds the hole at the outer side is laminated, and a joint surface with a large strain in the joint surfaces sandwiching the gasket While folding back the folded portion of the intermediate plate to the side, the height of the convex bead of the surface plate of the joint surface side with a large strain is made higher than the height of the convex bead of the other surface plate, To do.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings of the embodiments. 2 is a plan view showing a first embodiment of a cylinder head gasket using a laminated metal gasket of the present invention, and FIG. 1 is a sectional view taken along line AA of FIG. FIG. 3 is a sectional view showing a state in which the gasket of the first embodiment is clamped and sandwiched between the joint surfaces of the cylinder head and the cylinder block. FIG. 4 is a sectional view showing a second embodiment,
2 is a cross-sectional view corresponding to the cross-sectional view taken along the line AA of FIG. 1.
FIG. 5 is a cross-sectional view showing the third embodiment and is a cross-sectional view corresponding to the cross-sectional view taken along the line BB of FIG. In each figure, the same reference numerals indicate the same parts.

1 to 3, reference numeral 1 denotes a cylinder head gasket made of the laminated metal gasket of the present invention. The gasket 1 is a hole to be sealed as a combustion chamber hole 2, a cooling water passage hole, and an oil. A liquid passage hole 3 such as a passage hole and a bolt hole 4 into which a tightening bolt is inserted are provided. In FIG. 2, for simplification of the drawing, only two liquid passage holes 3 are shown, and the others are omitted.

As shown in FIG. 1, the gasket 1 is composed of an intermediate plate 7 having a folded portion 8 at the periphery of the combustion chamber hole 2, and surface plates 5 and 6 laminated on both sides of the intermediate plate. Each of the face plates 5 and 6 has a convex bead 9 surrounding the combustion chamber hole 2 at a position outside the folded portion 8 of the intermediate plate 7.
Alternatively, the surface plates 5 and 6 are arranged so that the convex tops of the beads 9 and 10 of the surface plates 5 and 6 are in contact with the intermediate plate and face each other. Reference numeral 11 denotes a sealing material layer made of heat-resistant and flexible rubber or synthetic resin provided on at least the outer surface of the face plates 5 and 6 (on both sides of the face plate in FIG. 1), such as a joint surface or an intermediate plate surface. It functions as a so-called microseal that compensates for roughness and minute scratches.

In the gasket of FIG. 1, as will be described later with reference to FIG. 3, the upper side of the figure abuts on the joint surface of the cylinder head, and the lower side of the figure abuts on the joint surface of the cylinder block. Although sandwiched, in the gasket shown in FIG. 1, the gasket is configured so that a larger strain is generated in the joint surface on the cylinder head side, and the folded-back portion 8 of the intermediate plate 7 includes the combustion chamber hole 2 of the intermediate plate. Of the convex bead 9 provided on the surface plate 5 that abuts on the joint surface of the cylinder head. Convex beads 10 provided on the face plate 6
It is formed sufficiently higher than the height of.

In FIG. 3, the gasket 1 of FIG. 1 (however, the sealing material layer 11 is not shown for simplification) is mounted between the joint surface 23 of the cylinder head 21 and the joint surface 24 of the cylinder block 22 of the engine. Then, the bolt 25 is fastened and the gasket 1 is sandwiched between the joint surfaces 23 and 24 and tightened, but the joint surface 23 of the cylinder head 21 is shown.
Is distorted from the state of the dotted line (substantially parallel to the joint surface 24 of the cylinder block) before the bolt fastening to the state of the solid line by the fastening force of the bolt, and between the cylinder head 21 and the cylinder block 22 at the peripheral edge of the combustion chamber 20. The gap G is increasing.

In FIG. 3, the joint surface 23 of the cylinder head is more distorted than the joint surface 24 of the cylinder block, but this is not always the case, and depending on the shape of the cylinder block, the cylinder block side. Larger strain may occur on the joint surface 24 of the above. However, in many cases, the tightening of the bolts and the addition of the explosive internal pressure to the bolts accelerate the deformation of the joint surface of the cylinder head, and the joint surface 23 of the cylinder head is more distorted. Therefore, in each of the above-described first embodiment and each of the embodiments described later, a gasket configured so that a larger strain is generated in the joining surface on the cylinder head side on the upper side of the drawing is shown and described.

Joining surface 23 between the cylinder head and the block
In the gasket 1 according to the present invention sandwiched between No. 24 and No. 24, as shown in FIG. 3, due to the presence of the folded-back portion 8, the gap at the periphery of the combustion chamber hole, which is thicker than the other portions, is increased by the strain. G is compensated to seal the gas in the combustion chamber 20, and the beads 9 and 10 of the surface plates 5 and 6 are pinched to form a seal line having a high surface pressure on the joint surface. The bead height of the convex bead 9 of the surface plate 5 which is formed but abuts on the joining surface 23 of the cylinder head has a bead height which abuts on the joining surface 24 of the cylinder block.
Since the bead 9 is formed sufficiently higher than the bead height of the convex bead 10 and the restoring amount of the bead 9 is large, the bead 9 can follow the large distortion and deformation of the joining surface 23 well, and secures the necessary restoring surface pressure. it can. Therefore, no leakage occurs.

Further, the folded-back portion 8 of the intermediate plate 7 is
Since the peripheral edge of the combustion chamber hole is bent toward the cylinder head side, the folded portion 8 acts to reduce expansion and contraction of the convex bead 9 due to the internal pressure of explosion, and has a height higher than that of the convex bead 10. It is possible to protect the convex bead 9 which has a high hardness and is liable to be settled or cracked.

In the gasket of the second embodiment shown in FIG. 4, the second intermediate plate 12 is provided on the lower side of the intermediate plate 7 having the folded portion 8, that is, on the cylinder block side, and abuts on the joint surface of the cylinder block. The convex top portion of the convex bead 10 of the face plate 6 contacts the lower surface of the second intermediate plate 12. Except for this point, the convex bead 9 of the surface plate 5 has a height higher than that of the convex bead of the surface plate 6, and the convex top of the convex bead abuts on the intermediate plate 7 having the folded portion 8. This is the same as in the case of one embodiment.

The structure of this second embodiment is used for manufacturing the laminated metal plate gasket according to the present invention, in which the surface plates 5 and 6 are provided with convex beads 9 (height h ₁ ) and convex beads 10 (height h _2). ) And have the same bead height (h ₁ = h ₂ ),
After assembling the laminated metal gasket, as shown in FIG. 6 (however, the sealing material layer 11 is not shown),
This is precompressed, for example, by applying a compressive force P between flat plate-shaped molds T, so that the height h ₁ ′ of the convex bead 9 after precompression
This is an advantageous structure when the height h ₂ ′ of the convex beads 10 is made different.

That is, when the second intermediate plate 12 does not exist, according to the above manufacturing method, as shown in FIG. 7, a bend 13 is likely to occur inside the folded portion 8 of the intermediate plate 7, and the bead 9 is formed. Difference between the height h ₁ ′ of the bead 10 and the height h ₂ ′ of the bead 10 is small, and the degree of bending described above is likely to vary irregularly, and the value of h ₁ ′ −h ₂ ′ varies widely. When the second intermediate plate 12 is present, especially when it is thick to some extent, the resistance against the above-mentioned bending increases and desired heights h ₁ ′ and h ₂ ′ can be obtained. Therefore, the thickness of the second intermediate plate is made thicker than the thickness of the intermediate plate 7, for example,
It is desirable to select a relatively thick thickness such as 0.3 to 0.5 mm.

In the seal structure around the combustion chamber hole 2 in the third embodiment shown in FIG. 5, the edge 15 around the combustion chamber hole 2 is above the intermediate plate 7 having the folded portion 8, that is, on the cylinder head side. An adjusting plate 14 is provided outside the folded-back portion 8 and inside the convex bead 9 and has a thickness smaller than the thickness of the intermediate plate. By providing the adjusting plate 14, it is possible to finely adjust the difference between the thickness of the peripheral portion of the combustion chamber hole 2, that is, the thickness of the portion including the folded portion 8 and the thickness of the other portions. Except for this point, the seal structure around the combustion chamber hole 2 of the third embodiment is the same as the seal structure of the first embodiment.

Since FIG. 5 shows a sectional view corresponding to the sectional view taken along the line BB in FIG. 1, the liquid passage hole 3 is shown in FIG.
A similar seal structure provided around the is also shown.
Since the structure of the seal structure around the liquid passage hole 3 is exactly the same as the structure of the seal structure around the combustion chamber hole 2 described above, detailed description thereof will be omitted. The same or corresponding parts are designated by the same reference numerals.

However, since the seal surface pressure around the liquid passage hole 3 is not as large as that around the combustion chamber hole 2, the seal structure according to the present invention as described above is not necessarily required. Any sealing structure may be used as long as it can provide a large sealing structure capable of following a joint surface that is largely distorted or deformed. For example, as shown in FIG. 9, a step bead is formed around the liquid passage hole 3 of the surface plates 5 and 6. 16 and 17 are provided, and the step of the step bead 16 of the face plate 5 is set to the step bead 1 of the face plate 6.
You may make it larger than the level difference of 7. Further, in the drawing, an example is shown in which the tops of the convex beads 9 and 10 project toward the intermediate plate, but the projecting direction of the tops of the convex beads is not limited to this.

[0023]

Since the laminated metal gasket according to the present invention has the structure as described above, the folded portion of the intermediate plate compensates for the increase in the gap at the periphery of the hole to be sealed due to the distortion of the joint surface, and Since the convex bead that abuts the joint surface with a large height and has a large amount of restoration follows the distortion and deformation of the joint surface well, and secures the necessary restoring surface pressure, from the side of the joint surface with large distortion Leakage can be effectively prevented. Further, the convex bead having a high height of the surface plate that abuts the joint surface having a large strain is protected by the folded portion in which the peripheral edge of the hole of the intermediate plate is folded back toward the surface plate, and the expansion / contraction deformation of the bead is reduced Therefore, even though the bead height is high, it is possible to prevent the bead from becoming tired or injured.

[Brief description of drawings]

1 is a cross-sectional view taken along the line AA of FIG.

FIG. 2 is a plan view of a first embodiment of a cylinder head gasket using a laminated metal gasket of the present invention.

FIG. 3 is a cross-sectional view showing a state in which the gasket of the first embodiment is sandwiched between the joint surfaces of the cylinder head and the cylinder block.

4 is a cross-sectional view showing a second embodiment, which is a cross-sectional view corresponding to the cross-sectional view taken along the line AA of FIG.

5 is a cross-sectional view showing a third embodiment, which is a cross-sectional view corresponding to the cross-sectional view taken along the line BB of FIG.

FIG. 6 is an explanatory diagram in the case of manufacturing the gasket of the second embodiment by a precompression method.

FIG. 7 is an explanatory diagram of problems when manufacturing by pre-compression.

FIG. 8 is a cross-sectional view of a cylinder head gasket made of a conventional laminated metal gasket.

FIG. 9 is a cross-sectional view when a step bead is provided around the liquid passage hole.

[Explanation of symbols]

 2 Combustion chamber hole 3 Liquid passage hole 5 and 6 Surface plate 7 Intermediate plate 8 Folding portion 9 and 10 Convex bead 12 Second intermediate plate 14 Adjustment plate 21 Cylinder head 22 Cylinder block

Claims (2)

[Claims] 1. Elasticity in which convex beads that surround the hole are provided on both sides of an intermediate plate made of metal, in which a folded part is provided on the periphery of the hole to be sealed, at positions outside the folded part. In a laminated metal gasket in which a surface plate made of a metal plate is laminated, the folded portion of the intermediate plate is folded back to the joint surface side where the distortion is large among the joint surfaces sandwiching the gasket, and the joint surface where the distortion is large. A laminated metal gasket, wherein the height of the convex bead of the side surface plate is made higher than the height of the convex bead of the other surface plate. 2. The laminated metal gasket according to claim 1, wherein the laminated metal gasket is a cylinder head gasket, and the height of the convex bead on the surface plate on the cylinder head side is the convex shape on the surface plate on the cylinder block side. A cylinder head gasket characterized by being made higher than the bead height.