JPH06337069A - Metallic gasket - Google Patents

Abstract

PURPOSE:To provide a metallic gasket having the capability to press and support a sub-combustion chamber member pertinently, while maintaining the required sealing quality. CONSTITUTION:A substrate 20 made of metallic plate is provided with a combustion chamber hole 21 drilled through a position faced to a combustion chamber. Also, an annular bead 23 is formed along a peripheral section surrounding the hole 21 and a section 20P faced to a sub-combustion chamber member 5. In addition, a presser bead 24 independent of the annular bead 23 is formed on the section 20P faced to the member 5 of the substrate 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal gasket for an internal combustion engine, and more particularly to a metal gasket suitable for a cylinder head gasket of a diesel engine.

[0002]

2. Description of the Related Art It is well known that a gasket is interposed between joining members to prevent leakage of pressure fluid from the joining surfaces. For example, in a cylinder head gasket interposed between a cylinder head and a cylinder block of an automobile engine, it is difficult to seal the combustion gas because not only high temperature and high pressure but also large changes in temperature and pressure. For this reason, various gaskets have been proposed, but recently, a metal gasket made of a metal plate material has attracted attention.

Further, in a diesel engine with a sub-combustion chamber, a sub-combustion chamber member that defines the sub-combustion chamber facing the combustion chamber, that is, a die is fitted into a hole on the lower surface of the cylinder head. Is larger than the thermal strain in other parts. For this reason, in Japanese Utility Model Publication No. 3-13555, a first bead surrounding the base is provided near the base,
A metal laminated gasket in which both ends of the first bead are connected to a second bead provided along a cylinder hole, and further, first and second beads are connected to each other by a third bead outside the first bead. Proposed.

[0004]

In the metal laminated gasket described in the above publication, the bead portion is formed on the middle plate, and the outer edge of the die and the edge of the cylinder hole intersect with each other.
The first bead portion or the second bead portion serves as the first seal portion,
It is described that the third bead portion functions as the second seal portion, and any of the drawings discloses the structure of the first to third bead portions at the intersecting portions. However, in any of the embodiments, the annular bead is not provided on the peripheral edge portion surrounding the portion facing the combustion chamber hole and the die, and for example, the combustion chamber hole shown in FIGS. 2 and 3 is used. Also in the embodiment provided with the second bead portion corresponding to the surrounding annular bead, the second bead portion is provided continuously across substantially the center of the portion facing the die.

FIG. 5 of the above publication also shows an embodiment in which a second bead portion is formed around the portion facing the combustion chamber hole and the die, but the portion contacting the die is notched in a circular shape. It is described that a compression material is engaged with the cutout portion. As described above, in the above publication, the bead portion or the like is formed on the middle plate arranged between the upper plate and the lower plate, and the bead portion is substantially continuous to the bead portion at the portion corresponding to the die. Are formed or a compression material is provided. However, if an annular bead is formed surrounding the combustion chamber hole and the portion corresponding to the die, a bead is formed substantially continuously from the annular bead for holding the die, or if a compression material is engaged, the bead is formed. The sealing property of the joint between the contacting portion and the combustion chamber hole becomes a problem.

Therefore, the present invention can appropriately press and support the sub-combustion chamber member while ensuring a predetermined sealing property in the internal combustion engine provided with the sub-combustion chamber member that defines the sub-combustion chamber facing the combustion chamber. It is intended to provide a metal gasket.

[0007]

In order to achieve the above object, the present invention provides a metal gasket to be mounted on an internal combustion engine having an auxiliary combustion chamber member that defines an auxiliary combustion chamber facing the combustion chamber. And a substrate having a combustion chamber hole formed at a position facing the combustion chamber and having an annular bead formed at a peripheral edge portion surrounding the combustion chamber hole and a portion facing the auxiliary combustion chamber member. A pressing bead independent of the annular bead is formed on a portion of the substrate facing the auxiliary combustion chamber member.

In particular, in a metal gasket mounted on an internal combustion engine having an auxiliary combustion chamber member that faces the combustion chamber, the auxiliary metal gasket is made of a metal plate material, and a combustion chamber hole is formed at a position facing the combustion chamber. And a first substrate having an annular bead formed in a peripheral portion surrounding a portion facing the combustion chamber hole and the sub-combustion chamber member, and a metal plate material, and facing the combustion chamber. A combustion chamber hole is formed at a position, an annular bead is formed in a peripheral edge portion surrounding the combustion chamber hole and a portion facing the auxiliary combustion chamber member, and the annular bead is formed in a portion facing the auxiliary combustion chamber member. A second substrate having a presser bead independent of the bead; and an intermediate plate having the combustion chamber hole and interposed between the first substrate and the second substrate. Each of the first substrate and the second substrate via a plate It is desirable that the top portion of the annular bead is configured to polymerization to face.

The metal gasket may be disposed so that the second substrate is on the cylinder head side of the internal combustion engine.

The width of the pressing bead may be larger than the width of the annular bead. Further, it is preferable that the pressing bead is formed in an arc shape concentric with the annular bead.
Further, it is desirable that the diameter of the pressing bead is larger than the diameter of the annular bead around the combustion chamber hole.

[0011]

When the metal gasket having the above structure is interposed between the joining members, for example, between the cylinder head and the cylinder block of the diesel engine and they are fastened with a predetermined tightening force, the annular bead and the The presser bead is compressed. The elastic restoring force of the annular bead thus compressed and deformed ensures a predetermined surface pressure on the joining member, and the holding bead appropriately presses and supports the auxiliary combustion chamber member.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the metal gasket of the present invention will be described below with reference to the drawings. 1 to 3 relate to an embodiment of the present invention, and FIG. 3 shows the entire metal gasket 1. As shown in FIG. 2, the metal gasket 1 of this embodiment is used as a cylinder head gasket interposed between the cylinder head 3 and the cylinder block 4 of a diesel engine with a secondary combustion chamber. This metal gasket 1 has a first substrate 10 and a second substrate 20 formed of an elastic metal plate, for example, a stainless steel plate (SUS),
An intermediate plate 30 is interposed between the two and has a three-layer structure.

A plurality of combustion chamber holes 11 and 21 (for example, four for an in-line four-cylinder internal combustion engine) corresponding to the number of cylinders are bored in a row on the first and second substrates 10 and 20, respectively. (Only a part of the combustion chamber hole 21 is shown in FIG. 1). Further, as shown in FIG. 3, a plurality of cooling water holes 22 and blow-by holes 25 are formed in the second substrate 20, and a plurality of bolt holes 26 are formed around the combustion chamber hole 21 at substantially equal intervals. It has been drilled (only one part is labeled in FIG. 3). Further, in order to join the first and second substrates 10 and 20, caulking holes 19 and 29 are provided at the outer peripheral ends of each, and caulked and fixed by eyelets 50. still,
Although the cooling water holes 12 and the like of the first substrate 10 are not shown in FIG. 3, they are formed similarly to the second substrate 20.

A peripheral edge portion surrounding the respective combustion chamber holes 11 and 21 of the first and second substrates 10 and 20 and a portion 20P facing the auxiliary combustion chamber member 5 (shown by a chain double-dashed line in FIG. 1) when the engine is mounted. The annular beads 13 and 23 are respectively formed on the first and second substrates 10 and 2 from the annular beads 13 and 23 to the combustion chamber holes 11 and 21, respectively, as shown in FIG.
Open end portions 10a and 20a having flat surfaces are formed at 0, respectively. A holding bead 24, which is independent of the annular bead 23, is formed on the portion 20p of the opening end 20a of the second substrate 20.

As shown in an enlarged view in FIG. 1, the presser bead 24 has an arcuate shape concentric with the annular bead 23, and its diameter Ra is set to be larger than the diameter Rb of the annular bead 23 around the combustion chamber hole 21. ing. As shown in FIG. 2, the presser bead 24
The width Wa is set to be larger than the width Wb of the annular bead 23.

Beads are also formed around the bolt holes 16 and 26 and the blow-by holes 15 and 25, and outer peripheral beads 18 and 28 are formed on the outer circumferences of the first and second substrates 10 and 20.
Are formed. These outer peripheral beads 18 and 28 are composed of inclined portions and have a shape half that of the annular beads 13 and 23, and are therefore called half beads.

Further, a so-called shim ring 40, which is a metal ring, for example, an annular spacer made of a stainless steel plate, is fixed to the opening end portion 20a of the second substrate 20. That is, as shown in FIG. 2, a shim ring 40 having a thickness substantially equal to the height of the annular bead 23 is entirely formed on the peripheral edge of the combustion chamber hole 21 of the opening end 20a of the second substrate 20 by, for example, a laser welding machine. It is welded substantially continuously over the circumference. Therefore, a continuous weld (not shown) is formed on the entire circumference of the annular shim ring 40. The thickness of the shim ring 40 is uniform over the entire circumference in this embodiment, but the thickness may be partially changed depending on the surface pressure distribution, or a seal member may be added.

The intermediate plate 30 is, for example, a soft rolled steel plate (S
PC) is formed into a substantially flat plate shape, and has combustion chamber holes 11 and 21.
Although not shown, holes similar to those formed in the first and second substrates 10 and 20 are formed, including the combustion chamber holes 31 that overlap with each other. A step portion 32 having a flat portion wider than the width of the shim ring 40 and having a predetermined step is formed on the peripheral edge portion of the combustion chamber hole 31 of the intermediate plate 30. This step 32
The step is formed smaller than the thickness of the shim ring 40. A plurality of, for example, five sheets of various thicknesses are prepared for the intermediate plate 30, and one of the most appropriate ones is selected at the time of assembling and used for adjusting the tightening thickness of the metal gasket 1.

With respect to the first and second substrates 10 and 20, the surfaces of the beads 13 and 23 on the projecting side are left as they are, and the surfaces on the opposite side thereof are, for example, unvulcanized with a vulcanizing agent added. It is advisable to form a vulcanized coating layer obtained by vulcanizing a vulcanized fluorocarbon rubber on the entire surface, and then laminate an unvulcanized coating layer thereon.
The unvulcanized coating layer on the vulcanized coating layer can be changed to an unvulcanized coating layer. Here, "non-vulcanized" means that it does not contain a vulcanizing agent, and "unvulcanized" means that it contains a vulcanizing agent but has not been vulcanized. Therefore, for example, unvulcanized rubber has the same properties as unvulcanized rubber in the initial stage, but vulcanization progresses during use to form a strong rubber layer, whereas unvulcanized rubber maintains a flexible state. To be done. Further, the intermediate plate 30 may have unvulcanized coating layers or non-vulcanized coating layers formed on both surfaces thereof.

As shown in FIG. 2, the metal gasket 1 having the above structure is interposed between the cylinder head 3 and the cylinder block 4 with the second substrate 20 facing the cylinder head 3. When a tightening force is applied between the cylinder head 3 and the cylinder block 4 by a bolt (not shown), the annular beads 13 and 23 are first compressed and deformed. Then, the cylinder head 3 and the cylinder block 4
When the spaces are tightened and the shim ring 40 and the intermediate plate 30 are compressed, the deformation of the annular beads 13 and 23 does not proceed any further, and the elastic restoring force of the first and second substrates 10 and 20 is in close contact with the cylinder block 4 and the cylinder head 3, respectively, and a predetermined surface pressure is secured.

At this time, the pressing bead 24 is also compressed between the auxiliary combustion chamber member 5 and the cylinder block 4, but since it is formed to have a width Wa wider than the width Wb of the annular bead 23, the auxiliary combustion chamber member 5 is formed. Is pressed and supported toward the cylinder head 3 with a pressing force smaller than the elastic restoring force of the annular bead 23. Moreover, since the presser bead 24 is not continuous with the annular bead 23 and is provided independently, it does not affect each other due to the compression deformation of each. Therefore, the sealing function of the annular bead 23 is not impaired by the compressive deformation of the pressing bead 24. Also,
Since the diameter Ra of the presser bead 24 is set to be larger than the diameter Rb of the annular bead 23 around the combustion chamber hole 21, it does not affect the surface pressure distribution by the annular bead 23. Furthermore, since the pressing bead 24 is not formed on the first substrate 10 but only on the second substrate 20, an excessive pressing force is not applied to the auxiliary combustion chamber member 5. .

When the metal gasket 1 of this embodiment is mounted on an engine, since it has a three-layer structure of the first and second substrates 10 and 20 and one intermediate plate 30, it has four or more layers. It is possible to suppress an increase in the capacity of the combustion chamber and reduce variations in the tightening thickness as compared with the laminated gasket. Moreover, since the intermediate plate 30 is formed of a soft rolled steel plate, when tightened, the surface roughness of the shim ring 40 is absorbed, and a good joint state between the two is maintained. Particularly in a diesel engine with a secondary combustion chamber, the squish area becomes high in heat, and the cylinder head 3 side becomes higher in heat than the cylinder block 4 side, resulting in a large heat load. Therefore, a gasket having heat distortion resistance corresponding to this is interposed. Is required. In this embodiment, since the second substrate 20 made of a stainless steel plate is arranged on the cylinder head 3 side, which is the high-heat side, and the shim ring 40 is welded thereto, sufficient strength is secured and good durability is ensured. can get.

FIG. 4 shows another embodiment of the metal gasket of the present invention, which has a three-layer structure in which an intermediate plate 30 is interposed between the first substrate 10 and the second substrate 20 as in the above-mentioned embodiment. However, in the present embodiment, the first substrate 1 is formed.
0 is provided with a shim ring 40, and a step portion 32 of the intermediate plate 30 is provided.
Are arranged opposite to those in FIG. FIG. 5 shows still another embodiment of the present invention, in which the shim ring 40 includes first and second shim rings 40.
Of the intermediate plate 30 instead of the substrates 10 and 20 of FIG.

[0024]

Since the present invention is configured as described above, it has the following effects. That is, in the metal gasket of the present invention, with respect to the substrate on which the annular bead is formed in the peripheral edge portion surrounding the portion facing the combustion chamber hole and the auxiliary combustion chamber member, the annular bead is provided in the portion facing the auxiliary combustion chamber member. Since it is supposed to form an independent presser bead,
The auxiliary bead chamber member can be appropriately pressed and supported by the pressing bead while ensuring a predetermined surface pressure by the annular bead.

Further, a first substrate having the annular beads formed thereon and a second substrate having the annular beads and the pressing beads formed thereon are polymerized via an intermediate plate so that the tops of the respective annular beads face each other. Also in the gasket, while the predetermined surface pressure is secured by the annular bead, the auxiliary combustion chamber member can be appropriately pressed and supported by the pressing bead, and especially the pressing bead is only formed on the second substrate. A stable support structure can be configured without applying an excessive pressing force to the auxiliary combustion chamber member.

[Brief description of drawings]

FIG. 1 is a plan view of a peripheral portion of a combustion chamber hole of a metal gasket according to an embodiment of the present invention.

FIG. 2 is a sectional view of a peripheral portion of a combustion chamber hole of a metal gasket according to an embodiment of the present invention, which is a sectional view taken along the line AA of FIGS. 1 and 3.

FIG. 3 is an overall plan view of a metal gasket according to an embodiment of the present invention.

FIG. 4 is a sectional view of a peripheral portion of a combustion chamber hole of a metal gasket according to another embodiment of the present invention.

FIG. 5 is a sectional view of a peripheral portion of a combustion chamber hole of a metal gasket according to still another embodiment of the present invention.

[Explanation of symbols]

 1 Metal Gasket 3 Cylinder Head 4 Cylinder Block 10 First Substrate 20 Second Substrate 11,21 Combustion Chamber Hole 12,22 Cooling Water Hole 13,23 Annular Bead 24 Holding Bead 15,25 Blow-by Hole 16,26 Bolt Hole 17 , 27 Annular beads 18, 28 Outer peripheral beads 19, 29 Caulking hole 30 Intermediate plate 31 Combustion chamber hole 32 Step 40 Shim ring

Claims (2)

[Claims] 1. A metal gasket to be mounted on an internal combustion engine, comprising a sub-combustion chamber member facing a combustion chamber, the sub-combustion chamber facing the combustion chamber. And a substrate having an annular bead formed in a peripheral portion surrounding the combustion chamber hole and a portion facing the auxiliary combustion chamber member, and the annular portion is provided in a portion of the substrate facing the auxiliary combustion chamber member. A metal gasket characterized by forming a presser bead that is independent of the bead. 2. A metal gasket to be mounted on an internal combustion engine, comprising a sub-combustion chamber member that faces the combustion chamber, the sub-combustion chamber facing the combustion chamber, the metal gasket being made of a metal plate material, and the combustion chamber hole facing the combustion chamber. And a first substrate having an annular bead formed in a peripheral portion surrounding a portion facing the combustion chamber hole and the sub-combustion chamber member, and a metal plate material, and facing the combustion chamber. A combustion chamber hole is drilled at the position,
An annular bead is formed in a peripheral edge portion surrounding the combustion chamber hole and a portion facing the auxiliary combustion chamber member, and a pressing bead independent of the annular bead is formed in a portion facing the auxiliary combustion chamber member. No. 2 substrate, and an intermediate plate which is provided with the combustion chamber hole and is interposed between the first substrate and the second substrate, and the first substrate and the intermediate substrate through the intermediate plate. A metal gasket, wherein the tops of the annular beads of each of the second substrates are polymerized such that they face each other.