JP2000297698A - Metal gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gasket, having capability of being compressed sufficiently throughout the entire length of a bead shaped seal portion, even wen a fastening force acting on the gasket is small or the rigidity of housings for catching the gasket in between is low, and demonstrate superior sealing property. SOLUTION: A metal gasket 1, having a base plate 2 made of an elastic metal plate, is provided with a combustion chamber hole 3, a plurality of bolt holes 4, and a bead shaped sealing portion 5 around the combustion chamber hole 3. The base plate 2 is provided with half beads 7, 11 with which flat portions 8, 12 are integrally formed via slanted portions 9, 13 at different heights, with respect to the base plate 2 over the entire length of the sealing portion 5, including portions 6 between the bolt holes. The bolt holes 4 are arranged within faces of flat surface portions 12 of the half beads 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gasket as a kind of a sealing device, and more particularly to a metal gasket.

[0002]

2. Description of the Related Art Conventionally, a metal gasket 51 shown in FIGS. 3 and 4 has been known, and is configured as follows (see Japanese Utility Model Laid-Open No. 63-193159).

First, as shown in FIG. 3, a substrate 52 made of an elastic metal plate is provided.
And a plurality of (six in the figure) bolt holes 54
Are provided, and a bead-shaped seal portion 55 is provided around the entire circumference of the combustion chamber hole 53.

[0004] This bead-shaped seal portion 55
As shown in FIG. 4A, a full bead 56 is formed at a portion between the bolt holes 54 (portion between the bolt holes), and as shown in FIG. A half bead 58 is formed at a portion (a portion around the bolt hole), and is formed by combining the full bead 56 and the half bead 58. The former full bead 56 is formed by integrally forming a bulged portion 57 having an arc-shaped cross section with the substrate 52.
The half bead 58 is formed by integrally forming a flat portion 59 at a different height position with respect to the substrate 52 on the substrate 52 via the inclined portion 60. Flat part 59 of the latter half bead 58
A bolt hole 54 is arranged in the plane of.

However, in the above-mentioned conventional metal gasket 51, since a part of the seal part 55 is provided with a full bead 56 having a characteristic that it is relatively hard to compress due to its structure as described above, When the tightening force acting on the gasket 51 is small, or when the rigidity of the housing sandwiching the gasket 51 is low, the full bead 56 cannot be sufficiently compressed, so that the sealing performance is not sufficiently exerted and leakage occurs. This may occur.

[0006]

SUMMARY OF THE INVENTION In view of the foregoing, the present invention provides a bead-shaped seal portion over its entire length even when the tightening force acting on the gasket is low or the rigidity of the housing sandwiching the gasket is low. It is an object of the present invention to provide a gasket which can be sufficiently compressed over the entirety thereof and which can exhibit excellent sealing performance.

[0007] In addition, even if deformation such as undulation occurs on the holding surface of the housing that holds the gasket, the seal portion can sufficiently follow the deformation, and a seal excellent in this respect is also provided. It is an object of the present invention to provide a gasket capable of exhibiting properties.

[0008]

In order to achieve the above object, a gasket according to a first aspect of the present invention is provided with a combustion chamber hole and a plurality of bolt holes in a substrate made of an elastic metal plate, and the periphery of the combustion chamber hole. In a metal gasket provided with a bead-shaped seal portion, a flat bead formed at a different height position with respect to the substrate is integrally formed on the substrate via a slope portion, the half bead including a portion between bolt holes of the seal portion. It is provided over the entire length of the seal portion, and the bolt hole is arranged in the plane of the flat portion of the half bead.

The metal gasket according to the second aspect of the present invention is the same as the metal gasket according to the first aspect,
The width of the slope in the portion between the bolt holes is formed smaller than the width of the slope in the portion around the bolt hole of the seal portion, and the height of the slope in the portion between the bolt holes is smaller than the height of the slope in the portion around the bolt hole. The height is made larger.

In the metal gasket according to the first aspect of the present invention having the above-described structure, the half bead having the characteristic of being easily compressed as compared with the full bead is formed not only in the peripheral portion of the bolt hole but also in the seal portion including the portion between the bolt holes. Since the gasket is provided over the entire length, even when the tightening force acting on the gasket is small or the rigidity of the housing sandwiching the gasket is low, the entire bead-shaped seal portion can be sufficiently compressed. Becomes As described above, the half bead is formed by integrally forming a flat portion at a different height position with respect to a substrate made of an elastic metal plate in a cantilever manner through a slope portion, and has a high compressibility and a low load. It has the characteristic of being able to exhibit sealing properties.

In addition, in the metal gasket according to the second aspect of the present invention having the above configuration, the width of the slope portion between the bolt holes is smaller than the width of the slope portion around the bolt holes of the seal portion. Is formed smaller, and the height of the slope portion in the portion between the bolt holes is formed larger than the height of the slope portion in the portion around the bolt hole. Half-beads have stronger resilience and are better at following the opponent. Therefore, even if deformation such as undulation occurs on the fastening surface of the housing that sandwiches the gasket, the seal portion can sufficiently follow this deformation in the portion between the bolt holes.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a gasket 1 according to the embodiment.
FIG. 2 is an enlarged sectional view taken along line AA of FIG.
2A is an enlarged cross-sectional view taken along the line BB in FIG.
This is shown in (B).

As shown in FIG. 1, a metal gasket 1 according to this embodiment includes a flat substrate 2 made of an elastic metal plate, and a combustion chamber is provided on the substrate 2 having a predetermined planar layout. A hole 3 and a plurality of (four in the figure) bolt holes 4 are provided, respectively, and a bead-shaped seal portion 5 is provided around the combustion chamber hole 3 endlessly over the entire circumference.

The bead-shaped seal portion 5 is formed as shown in FIG.
As shown in the figure, in a portion 6 between the bolt holes 4 (the portion between the bolt holes), a flat portion 8 at a different height position with respect to the substrate 2 is integrated with the substrate 2 via a slope portion 9. While being formed as a molded half bead 7, FIG.
As shown in FIG. 2B, in the peripheral portion 10 of the bolt hole 4 (the peripheral portion of the bolt hole), similarly, the flat portion 12 at a different height from the substrate 2 is integrally formed with the substrate 2 via the slope portion 13. Is formed as a half bead 11
That is, the seal portion 5 is formed by only the half beads 7 and 11 over the entire length.

In this half bead 7, 11 structure,
The flat portion 8 in the bolt hole portion 6 and the flat portion 12 in the bolt hole peripheral portion 10 are connected in series to form an endless surface. However, the width is 6 mm between bolt holes.
The flat portion 12 in the bolt hole peripheral portion 10 is formed to be larger than the flat portion 8 in the above, and a fastening bolt (not shown) is inserted into the plane of the flat portion 12 in the latter bolt hole peripheral portion 10. Bolt holes 4 are provided. The height position is determined by the height H ₂ of the slope portion 13 in the bolt hole peripheral portion 10 as described later.
And since there are differences in the height H ₁ of the inclined surface 9 of the bolt Anakan portion 6, they are different from one another In accordance with this,
Specifically, the flat portion 12 in the bolt hole peripheral portion 10
The flat portion 8 in the portion 6 between the bolt holes is higher than the flat portion, and a smooth step (not shown) is formed at the boundary between the two.
Are formed.

Also, the slope 9 in the bolt hole portion 6
And the slope 13 in the bolt hole peripheral portion 10 are connected in series to form an endless surface. However, the width is the width W ₂ of the slope portion 13 in the bolt hole peripheral portion 10.
Is formed smaller toward the width W ₁ of the inclined surface 9 in a more bolts Anakan portion 6, also the height, in volts Anakan portion 6 than the height H ₂ of the inclined surface portion 13 of the bolt hole surrounding portion 10 are the larger direction of the height H ₁ of the inclined surface 9, it is the repulsive force of the half bead 7 in bolt Anakan portion 6 than the half bead 11 of the bolt hole peripheral portion 10 by these is set strong.

The gasket 1 having the above structure is, for example, a cylinder head gasket interposed between a cylinder head and a cylinder block of an internal combustion engine to seal between both members. It is characterized in that it has the function and effect of (1).

That is, in the gasket 1 having the above-mentioned structure, no full bead having a characteristic that is relatively hard to be compressed is provided at all, and the seal portion 5 extends over its entire length as compared with the full bead. It is formed only by the half beads 7 and 11 having the property of being easily compressed.
Therefore, even when the tightening force acting on the gasket 1 is small, or when the rigidity of the housing or the like sandwiching the gasket 1 is low, the entire bead-shaped seal portion can be sufficiently compressed, thereby providing excellent sealing performance. Can be demonstrated.

In addition, in the gasket 1 having the above configuration, the width W ₁ of the slope 9 in the portion 6 between the bolt holes is larger than the width W ₂ of the slope 13 in the portion 10 around the bolt hole of the seal portion 5. together are smaller, in order towards the height H ₁ of the inclined surface 9 of the bolt Anakan portion 6 than the height H ₂ of the inclined surface portion 13 is formed larger in the bolt holes peripheral portions 10, the bolt holes around The half bead 7 in the portion 6 between the bolt holes has a higher repulsive force than the half bead 11 in the portion 10, and is therefore superior in followability to a mating material such as a housing. Therefore, even if deformation such as undulation occurs on the fastening surface of the housing that sandwiches the gasket 1, the seal portion 5 can sufficiently follow the deformation in the portion 6 between the bolt holes,
Therefore, also from this point, excellent sealing performance can be exhibited. Particularly in a low-rigidity housing, undulation is likely to occur at the initial stage or after fastening, and therefore, it is effective to use the gasket 1.

[0021]

The present invention has the following effects.

First, in the metal gasket according to the first aspect of the present invention having the above-described structure, a half bead formed integrally with the substrate through a slope portion at a flat portion at a different height with respect to the substrate has a sealing portion. The half bead is provided over the entire length of the seal portion including the portion between the bolt holes, and the bolt hole is arranged in the plane of the flat portion of the half bead. Even when the rigidity of the housing or the like sandwiching the seal is low, the entire bead-shaped seal portion can be sufficiently compressed, and thereby excellent sealing performance can be exhibited.

In addition, in the metal gasket according to the second aspect of the present invention having the above-described structure, the width of the slope between the bolt holes is smaller than the width of the slope around the bolt holes of the seal portion. Is formed smaller, and the height of the slope portion in the portion between the bolt holes is formed larger than the height of the slope portion in the portion around the bolt hole. The half bead has a stronger repulsive force and is therefore superior in followability to a mating material such as a housing. Therefore, even if deformation such as undulation occurs on the fastening surface of the housing that sandwiches the gasket, the seal portion can sufficiently follow this deformation in the portion between the bolt holes, and thus a seal excellent in this respect as well. Performance can be demonstrated.

[Brief description of the drawings]

FIG. 1 is a plan view of a metal gasket according to an embodiment of the present invention.

FIG. 2A is an enlarged sectional view taken along line AA in FIG. 1;
(B) is an enlarged sectional view taken along the line BB in FIG.

FIG. 3 is a plan view of a metal gasket according to a conventional example.

FIG. 4A is an enlarged sectional view taken along the line CC in FIG. 3;
(B) is an enlarged sectional view taken along line DD in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal gasket 2 Substrate 3 Combustion chamber hole 4 Bolt hole 5 Seal part 6 Between bolt holes 7,11 Half bead 8,12 Planar part 9,13 Slope 10 Peripheral part of bolt hole

Claims (2)

[Claims] A substrate (2) made of an elastic metal plate is provided with a combustion chamber hole (3) and a plurality of bolt holes (4), and a bead-shaped seal portion (5) is provided around the combustion chamber hole (3).
A metal gasket (1) provided with a flat portion (8) at a different height position with respect to the substrate (2).
The half bead (7) (11) obtained by integrally molding the substrate (2) with the substrate (2) through the slopes (9) and (13) is provided with the seal including the bolt hole portion (6) of the seal portion (5). A metal gasket provided over the entire length of the portion (5), wherein the bolt hole (4) is arranged in the plane of the flat portion (12) of the half bead (11). 2. The metal gasket according to claim 1, wherein a slant is formed in a peripheral portion (10) of the bolt hole of the seal portion (5).
The width (W) of the surface (13) ₂) To the portion between bolt holes (6)
Of the slope (9) (W₁) Is made smaller
And a slope at the peripheral portion (10) of the bolt hole.
Part (13) height (H₂)
Height (H) of the slope (9) in (6)₁) Is larger
A metal gasket characterized by being formed well.