JP2002054502A - Metal gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain sufficient seal performance even by decreasing rigidity of a tightened part in an intake/exhaust system of an engine and reducing a number of tightening bolts. SOLUTION: This metal gasket 1 of single plate type or layered type, having a port hole 2 corresponding to a port in an intake/exhaust system of an engine and an annular bead 4 enveloping the above port hole, is characterized by forming a sectional shape of the annular bead 4 in a wavy shape protruding in a reverse direction to each other from a flat part of a metal plate formed with this metal gasket to additionally have two chevron parts 4a, 4b continued to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal gasket used for an intake system or an exhaust system of an engine (hereinafter, referred to as an "internal combustion engine"). Corresponding port holes,
The present invention relates to a single-plate or laminated metal gasket comprising an annular bead surrounding the port hole.

[0002]

2. Description of the Related Art As a conventional metal gasket as described above, there is, for example, a two-layer type as shown in a plan view of FIG. In FIG. 7A, reference numeral 1 denotes a metal gasket,
2 is a port hole corresponding to the intake and exhaust system port of the engine, 3
Are two fastening bolt holes forming a pair with the port hole 2 interposed therebetween, 4 is an annular bead surrounding the port hole 2, 5 is a caulking hole for integrally caulking a plurality of metal gaskets 1 with eyelets. Are respectively shown. Here, the annular bead 4 has a so-called full bead shape having a chevron cross-sectional shape as shown in FIG. 7B, which is a cross-sectional view taken along the line FF in FIG. Are stacked in such a manner that the peaks of the chevron portions of the annular beads 4 are in contact with each other.

FIG. 8 is a cross-sectional view showing another conventional metal gasket at a position similar to FIG. 7 (b). This metal gasket has a cross section in which an annular bead 4 has an inclined surface inclined to one side. It is different from the above-described metal gasket only in that it has a so-called half bead shape, and in other respects, it is configured similarly to the above-described metal gasket. Here, two metal gaskets 1 are stacked in a direction in which they are in close contact with each other on the side (outer peripheral side) of the annular bead 4 opposite to the port hole 2 side.

In recent years, in order to reduce the weight of an engine for the purpose of reducing fuel consumption and the like, there has been a tendency to reduce the rigidity of a fastening portion such as a flange of an exhaust manifold or to reduce the number of fastening bolts. There is also a tendency to reduce the number of stacked metal gaskets for cost reduction.

[0005]

However, in the case where the rigidity of the fastening portion to the engine body and the number of fastening bolts can be sufficiently ensured and the number of stacked gaskets is not limited, the conventional metal gasket as described above has a sufficient seal. Although the performance could be secured, if the fastening part was reduced in rigidity or the number of fastening bolts was reduced, the fastening force and thermal deformation of the fastening part became uneven, and the annular beads were unevenly crushed, etc. In addition, the surface pressure of the bead is partially insufficient, and it is difficult to sufficiently prevent the leakage of the medium to be sealed with the conventional metal gasket as described above when the number of laminated layers is reduced.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a metal gasket which advantageously solves the above-mentioned problems. In a single-plate or laminated metal gasket comprising a port hole corresponding to a port of an intake and exhaust system of an engine, and an annular bead surrounding the port hole, the cross-sectional shape of the annular beat is
It is characterized in that the metal gasket is formed in a wave shape having two chevron portions that protrude in opposite directions from a flat portion of a metal plate and that are continuous with each other.

In the metal gasket of the present invention, the cross-sectional shape of the annular bead has a corrugated shape having two chevron portions which are mutually protruding from the flat portion of the metal plate forming the metal gasket and are continuous with each other. Since it is formed in a single piece, it has an annular bead with a collapse amount of two heights of the chevron part, so that the metal gasket is sandwiched between the engine body and the fastening part and tightened with fastening bolts Even if the tightening force and thermal deformation of the fastening part become uneven due to the low rigidity of the fastening part to the engine body and the reduction of the number of fastening bolts, the annular bead may be unevenly crushed, Surface pressure does not become partially insufficient, and therefore, it is possible to sufficiently prevent leakage of the medium to be sealed even with a single-plate type or a two-layer type by reducing the number of layers. Kill.

In the metal gasket according to the present invention, two of the annular beats may be stacked such that the peaks of the chevron portions of the annular beats are in contact with each other.
In this way, when the metal gasket is tightened, the annular beads press against each other at the peaks, so that the annular beads of each layer can be sufficiently elastically deformed, and the leakage of the medium to be sealed can be more effectively prevented. can do.

According to a third aspect of the present invention, there is provided a metal gasket comprising a port hole corresponding to a port of an intake and exhaust system of an engine, an annular bead surrounding the port hole, and a fastening bolt hole. In a metal gasket of a plate type or a laminated type, the cross-sectional shape of the annular beat is formed in a wave shape having two chevron portions which are mutually protruding from a flat portion of a metal plate forming the metal gasket and are continuous with each other. The bead width of two continuous chevron portions on the side closer to the fastening bolt hole is wider than the bead width of two contiguous chevron portions on the far side from the fastening bolt hole. is there.

According to the intake / exhaust metal gasket of the present invention, in addition to the function and effect of the first aspect, the bead width of the two continuous chevron portions is set closer to the fastening bolt hole than to the farther side. The sealing force on the side far from the fastening bolt hole and the sealing force on the side far from the fastening bolt hole can be increased by increasing the sealing force on the far side relative to the sealing force on the near side. Therefore, a high sealing force can be obtained for the entire annular beat. Note that the bead width may be changed gradually or may be changed stepwise.

According to a fourth aspect of the present invention, there is provided a metal gasket having a port hole corresponding to an exhaust port of a cylinder head of an engine, an annular bead surrounding the port hole, and a fastening bolt hole. In a single-plate or laminated metal gasket sandwiched between a cylinder head and an exhaust manifold flange, a cross-sectional shape of the annular beat projects in opposite directions from a flat portion of a metal plate forming the metal gasket. And two continuous chevron portions are formed in a wave shape, and the chevron portion of the two contiguous chevron portions that is closer to the fastening bolt hole abuts on the exhaust manifold flange. .

According to the metal gasket of the present invention, in addition to the function and effect of the configuration of the first aspect, a sealing force is further ensured at the angled portion abutting on the exhaust manifold flange, which is generally larger in thermal deformation than the cylinder head. Because it is easy to handle and close to the fastening bolt hole, it is possible to effectively cope with large thermal deformation of the exhaust manifold flange.

According to a fifth aspect of the present invention, there is provided a metal gasket comprising a port hole corresponding to a port of an intake / exhaust system of an engine, an annular bead surrounding the port hole, and a fastening bolt hole. In a metal gasket of a plate type or a laminated type, the cross-sectional shape of the annular beat is formed in a wave shape having two chevron portions which are mutually protruding from a flat portion of a metal plate forming the metal gasket and are continuous with each other. The projecting amount of two continuous chevron portions closer to the fastening bolt hole is smaller than the projecting amount of two continuous chevron portions farther from the fastening bolt hole.

According to the metal gasket of this invention, in addition to the function and effect of the first aspect, the projecting amount of the two continuous chevron portions is smaller on the side closer to the fastening bolt hole than on the side farther from the fastening bolt hole. In the above, the sealing force on the far side can be increased relative to the sealing force on the near side, and the sealing force by the bead on the side close to the fastening bolt hole and the sealing force by the bead on the side far from the fastening bolt hole can be increased. Since the difference can be reduced, a high sealing force can be obtained for the entire annular beat. Note that the protrusion amount may be gradually changed, or may be changed stepwise.

According to a sixth aspect of the present invention, there is provided a metal gasket having a port hole corresponding to an exhaust port of a cylinder head of an engine, an annular bead surrounding the port hole, and a fastening bolt hole. In a single-plate or laminated metal gasket sandwiched between a cylinder head and an exhaust manifold flange, a cross-sectional shape of the annular beat projects in opposite directions from a flat portion of a metal plate forming the metal gasket. And a wave shape having two chevron portions that are continuous with each other, and the protruding amount of the chevron portion of the two chevron portions that are in contact with the exhaust manifold flange is a chevron shape that is in contact with the cylinder head. It is characterized in that it is larger than the protrusion amount of the portion.

According to the metal gasket of the present invention, in addition to the function and effect of the structure of the first aspect, of the two continuous chevron portions, the exhaust gas manifold flange generally undergoes greater thermal deformation than the cylinder head. Since the protruding amount of the chevron portion in contact with the cylinder head is made larger than the protruding amount of the chevron portion in contact with the cylinder head, it is possible to effectively cope with large thermal deformation of the exhaust manifold flange.

[0017]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Here, FIG. 1A shows a first example of the metal gasket of the present invention.
FIG. 1B is a cross-sectional view taken along the line AA in FIG. 1A. In FIG. 1, the same parts as those shown in FIG. 7 are denoted by the same reference numerals. Shown.

The metal gasket according to the first embodiment, which is designated by reference numeral 1 in FIG. 1A, is used for an intake system or an exhaust system of an engine, and is constituted by a single metal plate (for example, a stainless steel plate). A single plate type, a port hole 2 corresponding to a port of an intake system or an exhaust system of an engine, two fastening bolt holes 3 forming a pair with the port hole 2 interposed therebetween, and a port hole 2 And an annular bead 4 formed.

In this embodiment, the annular beat 4
As shown in FIG. 1 (b), the two chevron portions 4a, 4a project from the flat portion of the metal plate forming the metal gasket 1 in opposite directions (vertical direction in the figure) and are continuous with each other. 4b.
1 (a) indicates the positions of the peaks of the chevron portions 4a and 4b.

The metal gasket 1 of this embodiment
Is, for example, SUS301EH having a thickness of 0.2 mm, for example.
It can be formed of stainless steel plate, in which case,
The dimensions of the annular beat 4 are preferably, as shown,
The width in the radial direction is 4 to 8 mm, and the height of each chevron portion 4a, 4b from the flat portion of the steel plate is 0.1 to 0.25 mm.

According to the metal gasket 1 of this embodiment, the annular bead 4 has a crush amount corresponding to the height of the two chevron portions 4a and 4b, so that the metal gasket 1 is fastened to the engine body. In the state where it is sandwiched between parts and tightened with fastening bolts, the tightening force and thermal deformation of the fastening part become uneven due to low rigidity of the fastening part to the engine body and reduction of the number of fastening bolts, and the ring Even if the bead 4 is unevenly crushed, the surface pressure of the annular bead does not become partially insufficient. Therefore, the number of laminations can be reduced and the sealing can be performed even in a single plate type as in this embodiment. Leakage of the medium (exhaust gas or the like) to be performed can be sufficiently prevented.

FIG. 2 is a sectional view showing a second embodiment of the metal gasket of the present invention at the same position as that of FIG. 1B. In FIG. 2, the same parts as those of the first embodiment are the same. Indicated by reference numerals. The metal gasket of the intake / exhaust system according to the second embodiment is also used for an intake system or an exhaust system of an engine. A two-layer metal gasket according to the first embodiment is formed by stacking two metal gaskets and turning one of the metal gaskets upside down. Here, of the two chevron portions 4a and 4b, the chevron portions 4a closer to the port holes 2 corresponding to the ports of the intake system or the exhaust system of the engine are brought into contact with each other, and the fastening bolt holes 3a Are laminated with the chevron portion 4b closer to the outside facing outward.

According to the metal gasket of the second embodiment, the same operation and effect as those of the metal gasket of the first embodiment can be further enhanced. In addition, the angled portion 4b closer to the fastening bolt hole 3 can be formed. Since the angled portion 4b which is directed outward and comes into contact with the fastening portion where thermal deformation is generally large is on the side closer to the fastening bolt hole 3 where it is easier to secure a sealing force, it is also effective for large thermal deformation of the fastening portion. Can be handled.

FIG. 3A is a plan view showing a third embodiment of the metal gasket of the present invention, and FIG.
FIG. 3A is a cross-sectional view taken along the line BB, and FIG.
FIG. 4A is a sectional view taken along the line CC of FIG. 3A, and in FIG. 3, the same parts as those shown in FIG.

The metal gasket of the third embodiment is used for an intake system or an exhaust system of an engine, similarly to the first embodiment, and is a single plate type made of a single metal plate (for example, a stainless steel plate). And a port hole 2 corresponding to a port of an intake system or an exhaust system of the engine.
And two fastening bolt holes 3 forming a pair with the port hole 2 interposed therebetween, and an annular bead 4 surrounding the port hole 2. Also in this embodiment, the cross-sectional shape of the annular beat 4 is changed from the flat portion of the metal plate forming the metal gasket 1 to the opposite direction (vertical direction in the figure) as shown in FIGS. 3 (b) and 3 (c). And is formed in a wavy shape having two chevron portions 4a and 4b which are continuous with each other. The dashed line in FIG. 3A indicates the positions of the peaks of the chevron portions 4a and 4b.

On the other hand, in the third embodiment, FIGS.
As shown in FIG. 3C, the bead width of the two continuous chevron portions 4a and 4b on the side closer to the fastening bolt hole 3 is increased by the bead width of the two continuous chevron portions 4a and 4b on the far side from the fastening bolt hole 3. It is wider than the bead width.

According to the metal gasket of the third embodiment, in addition to the same operation and effect as the metal gasket of the first embodiment, the bead width of the two continuous chevron portions 4a and 4b is increased from the fastening bolt hole 3. By making it wider on the near side than on the far side, the sealing force on the far side can be increased relative to the sealing force on the near side. Since the difference from the sealing force due to the bead on the far side can be reduced, a high sealing force can be obtained as a whole of the annular beat 4. The bead widths of the two chevron portions 4a, 4b are gradually changed in this embodiment, but may be changed stepwise.

FIG. 4 shows a fourth embodiment of the metal gasket of the present invention, together with an engine cylinder head 6 and an exhaust manifold flange 9 as a fastening member fastened thereto, at a position similar to FIG. 1B. In the figure, the same parts as in the first embodiment are indicated by the same reference numerals. Reference numerals 7 and 8 in the figure denote cylinder heads 6.
The exhaust port and fastening bolt holes 10 and 11 indicate the port hole and fastening bolt hole of the exhaust manifold flange 9, respectively.

The metal gasket of the fourth embodiment is used for an exhaust system of an engine, and is a single-plate type made of a single metal plate (for example, a stainless steel plate) and corresponds to an exhaust port of the engine. And a pair of fastening bolt holes 3 forming a pair with the port hole 2 interposed therebetween, and an annular bead 4 surrounding the port hole 2. Also in this embodiment, the cross-sectional shape of the annular beat 4 is changed from the flat portion of the metal plate forming the metal gasket 1 in the opposite directions (vertical direction in the figure) to the two convex portions 4a, 4b.

On the other hand, in the fourth embodiment, as shown in FIG. 4, of the two continuous mountain portions 4a and 4b, the one of the mountain portions 4b closer to the fastening bolt hole 3 abuts on the exhaust manifold flange 9. Let me. That is, the point P in the figure
1 is a contact point to the cylinder head 6, point P2 is a contact point to the exhaust manifold flange 9, point P1 is located at the chevron portion 4a, and point P2 is located at the chevron portion 4b.

According to the metal gasket of the fourth embodiment, in addition to the same operation and effect as the metal gasket of the first embodiment, a chevron portion which is in contact with the exhaust manifold flange 9 which generally has larger thermal deformation than the cylinder head 6. To
Since the angled portion 4b is closer to the fastening bolt hole 3 and can easily secure the sealing force, it is possible to effectively cope with a large thermal deformation of the exhaust manifold flange 9.

FIG. 5A is a plan view showing a fifth embodiment of the metal gasket of the present invention, and FIG.
FIG. 5A is a sectional view taken along the line D-D, and FIG.
FIG. 6A is a cross-sectional view taken along the line EE in FIG. 5A, and in FIG. 5, the same parts as those shown in FIG. 1 are denoted by the same reference numerals.

The metal gasket of the fifth embodiment is used for an intake system or an exhaust system of an engine similarly to the first embodiment, and is a single plate type made of a single metal plate (for example, a stainless steel plate). And a port hole 2 corresponding to a port of an intake system or an exhaust system of the engine.
And two fastening bolt holes 3 forming a pair with the port hole 2 interposed therebetween, and an annular bead 4 surrounding the port hole 2. Also in this embodiment, as shown in FIGS. 5B and 5C, the cross-sectional shape of the annular beat 4 is changed from the flat portion of the metal plate forming the metal gasket 1 to the opposite direction (vertical direction in the figure). And is formed in a wavy shape having two chevron portions 4a and 4b which are continuous with each other. 5 (a) indicates the positions of the peaks of the chevron portions 4a and 4b.

On the other hand, in the fifth embodiment, FIGS.
As shown in (c), the amount of protrusion of the two continuous chevron portions 4a and 4b close to the fastening bolt hole 3 from the flat portion (in the figure, H1 including the thickness of the flat portion) is shown. The projecting amount of the two continuous chevron portions 4a and 4b farther from the fastening bolt hole 3 from the flat portion (H2 including the thickness of the flat portion in the figure) is smaller than the projecting amount (H1). <H2).

According to the metal gasket of the fifth embodiment, in addition to the same functions and effects as those of the metal gasket of the first embodiment, the projecting amount of the two chevron portions 4a and 4b which are continuous with each other is increased from the fastening bolt hole 3. By making it smaller on the near side than on the far side, the sealing force on the far side can be increased relative to the sealing force on the near side. Since the difference from the sealing force due to the bead on the far side can be reduced, a high sealing force can be obtained as a whole of the annular beat 4. In addition, the protrusion amount of the two chevron portions 4a and 4b is
In this embodiment, it is changed gradually, but may be changed stepwise.

FIG. 6 shows a sixth embodiment of the metal gasket of the present invention, together with the cylinder head 6 of the engine and the exhaust manifold flange 9 as a fastening member fastened thereto, at the same position as in FIG. 1B. In the figure, the same parts as in the first embodiment are indicated by the same reference numerals. Reference numerals 7 and 8 in the figure denote cylinder heads 6.
The exhaust port and fastening bolt holes 10 and 11 indicate the port hole and fastening bolt hole of the exhaust manifold flange 9, respectively.

The metal gasket of the sixth embodiment is used for an exhaust system of an engine, and is a single-plate type made of a single metal plate (for example, a stainless steel plate) and corresponds to an exhaust port of the engine. And a pair of fastening bolt holes 3 forming a pair with the port hole 2 interposed therebetween, and an annular bead 4 surrounding the port hole 2. Also in this embodiment, the cross-sectional shape of the annular beat 4 is changed from the flat portion of the metal plate forming the metal gasket 1 in the opposite directions (vertical direction in the figure) to the two convex portions 4a, 4b.

On the other hand, in the sixth embodiment, as shown in FIG. 6, of the two continuous chevron portions 4a and 4b, the chevron portion 4 which abuts on the exhaust manifold flange 9.
b is made larger than the protrusion of the chevron 4a that contacts the cylinder head 6, and the chevron that contacts the exhaust manifold flange 9 is connected to the chevron 4b closer to the fastening bolt hole 3. And That is, the point P1 in the figure is the point of contact with the cylinder head 6, the point P
Numeral 2 is a contact point to the exhaust manifold flange 9, point P1 is located at the chevron portion 4a, and point P2 is located at the chevron portion 4b.

According to the metal gasket of the sixth embodiment, in addition to the same functions and effects as those of the metal gasket of the first embodiment, a chevron portion in contact with the exhaust manifold flange 9 which is generally larger in thermal deformation than the cylinder head 6 is provided. 4b
The projecting amount of the exhaust manifold flange 9 is increased while the projecting amount of the exhaust manifold
Is formed as the chevron portion 4b on the side close to the fastening bolt hole 3 so that the sealing force can be more easily secured.
It is possible to effectively cope with large thermal deformation of the exhaust manifold flange 9.

Although the present invention has been described based on the illustrated examples, the present invention is not limited to the above-described examples. For example, the metal gasket of the present invention may have three or more fastening bolt holes, The number of holes may be two or more.

[Brief description of the drawings]

FIG. 1A is a plan view showing a first embodiment of a metal gasket according to the present invention, and FIG.
It is sectional drawing which follows the A line.

FIG. 2 is a cross-sectional view showing a second embodiment of the metal gasket of the present invention at a position similar to FIG. 1B.

3A is a plan view showing a third embodiment of the metal gasket of the present invention, FIG. 3B is a sectional view taken along line BB of FIG. 3A, and FIG. It is sectional drawing which follows the CC line of FIG.

FIG. 4 is a cross-sectional view showing a fourth embodiment of the metal gasket of the present invention at a position similar to FIG. 1B.

5A is a plan view showing a fifth embodiment of the metal gasket of the present invention, FIG. 5B is a cross-sectional view taken along line DD of FIG. 5A, and FIG. It is sectional drawing which follows the EE line of FIG.

FIG. 6 is a cross-sectional view showing a sixth embodiment of the metal gasket of the present invention at a position similar to FIG. 1B.

FIG. 7A is a plan view showing an example of a conventional intake / exhaust metal gasket, and FIG. 7B is an FF of FIG.
It is sectional drawing which follows a line.

FIG. 8 is a cross-sectional view showing another example of a conventional intake / exhaust metal gasket.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Intake / exhaust system metal gasket 2 Port hole 3 Fastening bolt hole 4 Annular bead 4a, 4b chevron part 5 Caulking hole 6 Cylinder head 7 Exhaust port 8 Fastening bolt hole 9 Exhaust manifold flange 10 Port hole 11 Fastening bolt hole P1 Contact point P2 Contact point

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Miyuki Soma 1-4-1 Chuo, Wako-shi, Saitama Pref. Honda Research Institute, Inc. (72) Inventor Shigeru Kobayashi 2-28-18 Harayama, Urawa-shi, Saitama Japan Inside Leakless Industrial Co., Ltd. (72) Inventor Hideaki Harada 2-28-18 Harayama, Urawa-shi, Saitama F Leamless Industrial Co., Ltd. F-term (reference) 3J040 BA01 EA06 EA12 EA28 FA01 HA16 HA20

Claims (6)

[Claims] 1. A single-plate or laminated metal gasket comprising: a port hole corresponding to a port of an intake / exhaust system of an engine; and an annular bead surrounding the port hole. A metal gasket, which is formed in a wave shape having two chevron portions continuous with each other and projecting in opposite directions from a flat portion of a metal plate forming the metal gasket. 2. The metal gasket according to claim 1, wherein two peaks of the chevron portion of the annular beat are stacked in a direction in which the peaks contact each other. 3. A single-plate or laminated metal gasket comprising: a port hole corresponding to a port of an intake / exhaust system of an engine; an annular bead surrounding the port hole; and a fastening bolt hole. The cross-sectional shape of the beat is formed in a wavy shape having two chevron portions continuous with each other while projecting in opposite directions from the flat portion of the metal plate forming the metal gasket, and forming a continuous shape on the side close to the fastening bolt hole. A metal gasket, characterized in that the bead width of the two chevron portions is wider than the bead width of two contiguous chevron portions remote from the fastening bolt hole. 4. An engine, comprising: a port hole corresponding to an exhaust port of a cylinder head of an engine; an annular bead surrounding the port hole; and a fastening bolt hole, sandwiched between the cylinder head and an exhaust manifold flange. In a single-plate or laminated metal gasket, the cross-sectional shape of the annular beat is formed in a wavy shape having two chevron portions that project in opposite directions from a flat portion of a metal plate forming the metal gasket and are continuous with each other. A metal gasket, characterized in that, of the two continuous chevron portions, a chevron portion closer to a fastening bolt hole is brought into contact with the exhaust manifold flange. 5. A single-plate or laminated metal gasket comprising: a port hole corresponding to a port of an intake / exhaust system of an engine; an annular bead surrounding the port hole; and a fastening bolt hole. The cross-sectional shape of the beat is formed in a wavy shape having two chevron portions continuous with each other while projecting in opposite directions from the flat portion of the metal plate forming the metal gasket, and forming a continuous shape on the side close to the fastening bolt hole. A metal gasket, characterized in that the projecting amount of the two chevron portions is smaller than the protruding amount of the two chevron portions that are continuous with each other on the side remote from the fastening bolt hole. 6. A port hole corresponding to an exhaust port of a cylinder head of an engine, an annular bead surrounding the port hole, and a fastening bolt hole, being sandwiched between the cylinder head and an exhaust manifold flange. In a single-plate or laminated metal gasket, the cross-sectional shape of the annular beat is formed in a wavy shape having two chevron portions that project in opposite directions from a flat portion of a metal plate forming the metal gasket and are continuous with each other. And forming a protrusion of a chevron portion of the two continuous chevron portions that abuts on the exhaust manifold flange larger than a protrusion amount of a chevron portion that abuts on the cylinder head. Yes, metal gasket.