JPH05118443A - Metal gasket - Google Patents

Abstract

PURPOSE:To secure the stable sealing performance over the whole periphery of a fluid hole, even in the case where the interval between the contiguous fluid holes is narrow, in a metal gasket in which at least two base plates are arranged so that the top parts of based are opposed. CONSTITUTION:Fluid holes 11 and 21 for the passing of the pressurized fluid are formed on the base plates 10 and 20 made of metal, and beads 13 and 23 are formed on the peripheries. The width of the bead 13 on the base plate 10 is formed narrower than the width of the bead 23 of the other base plate 20, and a metal ring 14 having a prescribed width is joined between the bead 13 and the fluid hole 11 of one base plate 10. These base plates 10 and 20 are arranged so that top parts of the beads 13 and 23 are opposed.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a metal gasket,
Particularly, the present invention relates to a metal gasket suitable as a cylinder head gasket of an internal combustion engine.

[0002]

2. Description of the Related Art It is well known that a gasket is interposed between joint members in order to prevent leakage of pressure fluid from the joint surface, for example, between a cylinder head and a cylinder block of an internal combustion engine. A cylinder head gasket is installed. Regarding this type of gasket, recently, a metal gasket made of a metal plate material has been receiving attention.
For example, a metal substrate is provided with a fluid hole through which a pressure fluid such as combustion gas passes, and a bead is formed around the fluid hole so that a high surface pressure can be secured to the joining member. Are known.

Further, as disclosed in Japanese Utility Model Laid-Open No. 59-188955, for example, in order to prevent the bead from plastically deforming due to a tightening force and deteriorating the sealing property, the bead of the metal gasket is prevented. It has been proposed that a surface pressure adjusting plate, which is a plate thinner than the protruding height, is provided in a portion other than the bead. For the same purpose, various types have been proposed in which a thick portion is formed on the substrate on the hole side with respect to the bead. Regarding the thick wall portion, for example, Japanese Utility Model Laid-Open No. 61-14748 discloses a thick wall portion formed by plating, and Japanese Utility Model Laid-Open No. 2-6855 discloses a thick wall portion by adhering or welding a sub-plate. Part or JP-A-64-35
Japanese Patent Publication No. 057 discloses a stopper (corresponding to a thick portion) formed by thermal spraying to impregnate a filler such as a resin to ensure a sealing function.

Further, Japanese Utility Model Publication No. 3-28208 discloses that
Regarding a laminated metal gasket in which the tops of the beads formed on the two substrates are directed in the same direction and an intermediate plate is interposed between the two substrates, the width of the first bead on one first substrate is It has been proposed to provide a compensating member that is formed smaller than the width of the second bead of the second substrate and that prevents the first bead from being pressed and deformed to a predetermined thickness or less around the combustion chamber hole of the first substrate.

[0005]

As the spacers for the surface pressure adjusting plate and the thick portion, the beads are adjusted so that they can be compressed and deformed to function as a sealing member, and at the same time, they can function as a sealing member themselves. It is desirable to use a material having a sealing property, and in view of assembling property, thickness control, cost, etc., it is desirable to bond the metal ring to the peripheral portion of the fluid hole of the substrate.

However, with the recent trend toward higher output and downsizing of internal combustion engines, the spacing between adjacent bores has become narrower and the spacing between adjacent combustion chamber holes in cylinder head gaskets has also become narrower. Therefore, the width of the metal ring has to be narrowed, and it becomes difficult to secure the sealing property. That is, since the width of the metal ring is formed uniformly over the entire circumference for the convenience of manufacturing and assembling, the width of the metal ring needs to be the narrowest part (the part located between the adjacent combustion chamber holes). ) Will be set to the width. Therefore, it is necessary to take additional measures such as providing a seal member around the bead. On the contrary, when the metal ring is set wide, the width of the bead is narrowed, and the durability of the bead is reduced.

By the way, the above-mentioned Japanese Patent Laid-Open No. 64-35057.
As shown in FIG. 6 of Japanese Patent Publication, in a metal gasket in which two substrates having the same shape having beads are arranged so that their tops face each other, a synergistic effect of the two beads is expected. The surface pressure of is secured. In the publication,
The stopper is formed by thermal spraying and then impregnated with a resin, which is different from the one that joins the metal ring in terms of its characteristics, manufacturing and assembly problems, etc., but temporarily replaces the stopper in the publication with a metal ring. However, the width of the stopper provided between the adjacent combustion chamber holes is narrow, and the same problem as described above occurs.

In the metal gasket described in Japanese Utility Model Publication No. 3-28208, the width of the first bead of one of the two substrates arranged symmetrically with respect to the intermediate plate is Although it is smaller than the width of the second bead of the other second substrate, the width of the compensation member is not particularly mentioned. Referring to the drawings, the compensating member is formed to have a width substantially the same as the width between the second bead of the second substrate and the combustion chamber hole, and accordingly, the compensating member and the first bead disposed on the first substrate. A gap is formed between them.

Also, in any of these metal gaskets, an intermediate plate is interposed between the two substrates, but when the two substrates are arranged so that the tops of the beads are directed in the same direction, the intermediate plate is interposed. A board is required. When the two substrates are arranged so that the tops of the beads are opposed to each other, the intermediate plate may be removed and both beads may be brought into contact with each other. However, if the beads of the two opposing substrates have the same shape, and if a deviation occurs between the two substrates during assembly, compressive force will be applied to the inclined portions of each bead instead of the tops of both beads. It becomes difficult to secure the surface pressure of. Therefore, in order to avoid this, a high degree of assembly precision is required.

In view of the above, the present invention provides a metal gasket having at least two metal substrates each having a bead formed around a fluid hole, and the tops of the beads are opposed to each other. It is an object of the present invention to ensure a stable sealing property over the entire circumference of the fluid hole even when the distance between the two is narrow.

[0011]

In order to achieve the above object, the present invention provides at least a metal substrate having a fluid hole through which a pressure fluid passes and a bead formed around the fluid hole. In a metal gasket having two substrates arranged such that the tops of the beads are opposed to each other, the bead width of one of the two substrates is smaller than the bead width of the other substrate. The metal ring is formed narrow and a metal ring having a predetermined width is joined between the bead of the one substrate and the fluid hole.

In the metal gasket, the two substrates may be arranged such that the bead tops of the one substrate and the bead tops of the other substrate are in direct contact with each other.

In the metal gasket, the height of the bead of the one substrate may be lower than the height of the bead of the other substrate.

[0014]

When the metal gasket having the above structure is interposed between the facing joining members, for example, between the cylinder head and the cylinder block, and both are fastened with a predetermined tightening force, two substrates are formed. Of the beads are compressed and deformed, and the elastic restoring force of the compressed and deformed beads ensures a predetermined surface pressure on the joining member. In this case, a metal ring is joined between the narrow bead of one substrate and the fluid hole, and the metal ring is set to a predetermined width sufficient to ensure the sealing function by itself. Thus, the narrow bead is deformed to a height equivalent to the thickness of the metal ring, but the subsequent deformation is prevented, so that the fatigue resistance of the bead is ensured. Moreover, since the tops of the narrow beads formed on one substrate and the tops of the beads on the other substrate face each other, when the tops of both beads are directly contacted with each other, a gap between the two substrates is required. Even if a slight deviation occurs, a compressive force is appropriately applied to the tops of both beads, and the desired plastic deformation is performed.

[0015]

Embodiments of the metal gasket of the present invention will be described below with reference to the drawings. As the metal gasket targeted by the present invention, a cylinder head gasket interposed between a cylinder head and a cylinder block of a multi-cylinder internal combustion engine is suitable, and a metal used as the cylinder head gasket as an example. The gasket will be described.

FIGS. 1 and 3 show an embodiment of the present invention. The metal gasket of this embodiment comprises an elastic metal plate, for example, a stainless steel plate (SUS) first substrate 10 and a second substrate 20. Having these first and second substrates 10, 20
A plurality of combustion chamber holes 11 and 21 are formed in each of the above. A plurality of cooling water holes (not shown) and a plurality of lubricating oil holes (not shown) are formed in the first and second substrates 10 and 20, respectively. Multiple bolt holes 1
2 (not shown for the second substrate 20) is punched.

The combustion chamber holes 11 and 21 have a number of holes corresponding to the number of cylinders (for example, four for an in-line four-cylinder internal combustion engine) arranged in a straight line, and around these combustion chamber holes 11 and 21,
As is apparent from FIG. 1, beads 13 and 23 are formed respectively. The widths of the beads 13 and 23 are formed uniformly over the entire circumferences of the combustion chamber holes 11 and 21, but the width W1 of the bead 13 is formed to be narrower than the width W2 of the bead 23.

Therefore, the width of the flat surface from the bead 13 of the first substrate 10 to the combustion chamber hole 11 is the second substrate 20.
The width of the flat surface from the bead 23 to the combustion chamber hole 21 is wider than the width of the flat surface of the first substrate 10, and the flat surface of the bead 13 on the flat surface of the first substrate 10 is provided with a perfect circular metal ring, for example, a stainless steel plate A spacer, a so-called shim ring 14, is joined. That is, the shim ring 14 is set to have a predetermined width sufficient to ensure the sealing function by itself, and is set thinner than the height of the bead 13 as shown in FIGS. Are substantially continuously welded to the first substrate 10. As a result, a welded portion 15 (not shown in FIG. 3) that is continuous over the entire circumference of the annular shim ring 14 is formed.

For example, a total of ten bolt holes 12 are formed around each combustion chamber hole 11 and 21 at substantially equal intervals, and fastening bolts (not shown) are inserted into each of them at the time of assembling, as shown in FIG. The first and second substrates 10 and 20 are arranged so that the tops of the beads 13 and 23 face each other and directly contact each other, and are clamped between the cylinder head 3 and the cylinder block 4. In this embodiment, the second substrate 20 is arranged so as to be on the cylinder block 4 side.
The substrate 10 may be arranged so as to be on the cylinder block 4 side.

When the above metal gasket is mounted on an internal combustion engine and a tightening force is applied, first, the tops of the beads 13 and 23 come into contact with each other, and the beads 13 and 23 are deformed by compression. At this time,
Since the height of the bead 13 is larger than the thickness of the shim ring 14, the bead 13 can deform until it becomes equal to the thickness of the shim ring 14, but it does not deform further. That is, when the space between the cylinder head 3 and the cylinder block 4 is tightened and the shim ring 14 is compressed, the deformation of the bead 13 does not proceed any further, and the elastic restoring force of the bead 13 causes the first substrate 10 to move to the first position. It comes into close contact with the second substrate 20 and the cylinder head 3.

As described above, the beads 13 of the first substrate 10
Is narrower and weaker than the bead 23 of the second substrate 20, but since the displacement is limited by the shim ring 14, there is no risk of cracking. Moreover, since the shim ring 14 is formed to have a predetermined width as described above, a predetermined sealing function is ensured. Further, at the time of assembly, the first and second substrates 10,
Even if there is a slight deviation between the two, the top of the bead 23 is wider than the top of the narrow bead 13, so that the state in which both tops are in contact with each other is substantially maintained, and it is appropriate for each top. Compressive force is applied. Therefore, a stable sealing property can be secured without changing the surface pressure distribution.

FIG. 2 shows another embodiment of the present invention.
The height T1 of the bead 13 of the first substrate 10 is the second substrate 2
It is formed lower than the height T2 of the bead 23 of 0. According to this embodiment, the fatigue resistance is improved as compared with the bead 13 in the embodiment of FIG.

FIG. 4 shows still another embodiment of the metal gasket of the present invention. The first substrate 10 and the second substrate 2 are shown in FIG.
The auxiliary plate 30 is interposed between the two zeros to form a three-layer structure. The sub plate 30 is formed into a substantially flat plate shape by a rolled steel plate (SPC) which is softer than the first and second substrates 10 and 20, and is superposed on the combustion chamber holes 11 and 21 of the first and second substrates 10 and 20. A combustion chamber hole 31 is provided. According to this embodiment, since the tops of the beads 13 and the beads 23 do not directly contact each other, even if a slight deviation occurs during assembly, the auxiliary plate 30
Appropriate compressive force is applied to each top via. And
Since the shim ring 14 is formed to have a predetermined width as in the above-described embodiment, a predetermined sealing function is ensured. Also in this embodiment, the height T1 of the bead 13 of the first substrate 10 may be lower than the height T2 of the bead 23 of the second substrate 20 as in the embodiment of FIG.

FIG. 5 shows a modification of the embodiment shown in FIG. 4, in which a step portion 32 is formed in the peripheral edge portion of the combustion chamber hole 31 of the sub plate 30, and a gap between the sub plate 30 and the shim ring 14 is formed in the sub plate 30. And the gap between the second substrate 20 and the second substrate 20 are substantially equal to each other. A first sub-plate and a second sub-plate (not shown) may be interposed between the first substrate 10 and the second substrate 20 to form a four-layer structure.

[0025]

Since the present invention is configured as described above, it has the following effects. That is, in the metal gasket of the present invention, the top of the narrow bead formed on one substrate and the top of the bead of the other substrate are configured to face each other, and the narrow bead of the one substrate is formed. Is deformed to a height equivalent to the thickness of the metal ring, but the metal ring reliably prevents the subsequent deformation, so that the fatigue resistance of the bead can be secured. Further, even when the space between the adjacent fluid holes is narrow, the metal ring having a predetermined width is joined, so that the sealing function thereof can secure a stable sealing property over the entire circumference of the fluid hole.

When the two substrates are arranged so that the tops of the beads directly contact each other, an appropriate compression force is applied to the tops of the beads even if a slight deviation occurs between the two substrates. Is added, it is easy to assemble and good workability can be obtained.

[Brief description of drawings]

1 is a partial cross-sectional view of a metal gasket according to an embodiment of the present invention, which is a cross-sectional view taken along the line AA of FIG.

FIG. 2 is a partial cross-sectional view of a metal gasket according to another embodiment of the present invention.

FIG. 3 is a plan view of a part of the first substrate that constitutes the metal gasket according to the embodiment of the present invention.

FIG. 4 is a partial cross-sectional view of a metal gasket according to still another embodiment of the present invention.

FIG. 5 is a partial cross-sectional view of a metal gasket showing a modified example of the embodiment of FIG. 4 of the present invention.

[Explanation of symbols]

 3 Cylinder Head 4 Cylinder Block 10 First Substrate 20 Second Substrate 11 and 21, Combustion Chamber Hole (Fluid Hole) 12 Bolt Hole 13,23 Bead 14 Shim Ring (Metal Ring) 30 Sub-plate 31 Combustion Chamber Hole

Front page continued (72) Inventor Kazuya Nakata 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (72) Inventor Zenichi Shinbo 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd.

Claims (3)

[Claims] 1. At least two metal substrates, each having a fluid hole through which a pressure fluid passes and a bead formed around the fluid hole, are provided, and the two substrates are provided on top of each bead. In the metal gaskets arranged to face each other, the width of the bead of one of the two substrates is formed to be narrower than the width of the bead of the other of the two substrates, and the bead and the fluid hole of the one substrate are formed. A metal gasket, characterized in that a metal ring having a predetermined width is joined to the metal gasket. 2. The metal gasket according to claim 1, wherein the two substrates are arranged such that a top portion of a bead of the one substrate directly abuts a top portion of a bead of the other substrate. .. 3. The metal gasket according to claim 2, wherein the bead height of the one substrate is lower than the bead height of the other substrate.