JPS63210465A - Metal gasket - Google Patents

Abstract

PURPOSE:To prevent the bead cut by making the bead width of the merging section of beads nearly equal to the bead width of the non-merging section. CONSTITUTION:A metal gasket 2 has a substrate 4 made of elastic metal plate, combustion chamber holes 6, and bolt holes 8. Beads 10 are formed on the substrate 4. The beads 10 merge between the combustion chamber holes 6 to form a merging section 12. The bead width L1 is made nearly equal to the bead width L2 of the non-merging section 14. That is, the bead width L2 of the non-merging section 14 is formed gradually narrower toward the merging section 12 so that L1 L2 at the merging section 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a metal gasket, and more particularly to a metal gasket that can prevent a drop in sealing pressure at a meeting point of beads and achieve effective sealing.

[Conventional technology]

2. Description of the Related Art A metal gasket is known in which a bead is formed on an elastic metal plate and the bead efficiently seals the joint surfaces of members to be joined. This metal gasket is interposed between, for example, a joint surface between a cylinder head and a cylinder block of an internal combustion engine, and forms a seal line on the joint surface by the tightening force of a bolt, thereby achieving a seal at a sealed portion.

As such a metal gasket, the applicant of the present invention has already filed an invention, for example, in Japanese Patent Application No. 81530/1982. In the metal gasket disclosed in this invention, the bead width is formed to be sufficiently larger than the bead height, and a surface treatment such as a sealing material is applied to the surface of the substrate, so that a seal can be achieved with a single substrate.

[Problem that the invention seeks to solve]

By the way, as shown in FIG. 3, in such a metal gasket 2, the beads 10 formed to surround the combustion chamber holes 6, which are the respective sealing parts, meet between the combustion chamber holes 6,
A meeting portion 12 may be formed. In such a meeting part 12, the bead width of the meeting part 12 is formed to be larger than the bead width L2 of the non-merging part 14 due to the plurality of beads 10 meeting. In this way, in the meeting part 12, the bead width is larger than the bead height, so the spring constant is smaller than that in the non-joining part 14, which causes a decrease in the sealing pressure of the meeting part 12, and the bonding surface This caused a problem in which the sealing pressure applied to the parts was uneven.

For this reason, there is an inconvenience that gas, oil, etc. leak from the meeting portion 12 where the sealing pressure is weak, and a large fastening force must be applied to ensure the sealing performance of the meeting portion 12 where the sealing pressure is weak. Therefore, an excessive fastening force is applied to the non-meeting portion 14, resulting in bead breakage, resulting in a reduction in sealing performance.

[Purpose of the invention]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to avoid a decrease in the sealing pressure at the joining part of the beads that seal each sealing part, and to prevent unevenness in the sealing pressure applied to the joint surfaces, thereby achieving an effective seal. Our goal is to create a metal gasket that can fulfill the following needs.

[Means for solving the problem] In order to achieve this object, the present invention provides a metal gasket that performs sealing by forming beads on an elastic metal plate.
The present invention is characterized in that the bead width of the meeting portion of the beads sealing the respective seal portions provided on the elastic metal plate is formed to be approximately equal to the bead width of the non-meeting portion.

[Effect]

According to the structure of the present invention, the bead width of the meeting part of the beads sealing each sealing part is formed to be approximately equal to the bead width of the non-meeting part, so that the bead width of the meeting part is larger than that of the non-merging part. The spring constant never becomes smaller. This avoids a decrease in the sealing pressure at the meeting portion and also prevents the sealing pressure from becoming uneven.

〔Example〕

Next, embodiments of the present invention will be described in detail based on the drawings.

1 and 2 show an embodiment of the invention. In the figure, 2 is a metal gasket, 4 is a substrate made of an elastic metal plate, 6 is a combustion chamber hole, and 8 is a bolt hole. A hole 10 is formed in the substrate 4 so as to surround the combustion chamber hole 6.

These beads 10 meet between the combustion chamber holes 6 to form a meeting portion 12 . In this way, multiple beads 1
As shown in FIG. 2, the bead width of the meeting portion 12 where the zeros meet is approximately equal to the bead width L2 of the non-meeting portion 14.

That is, the bead width L2 of the non-meeting portion 14 toward the meeting portion 12
is gradually narrowed, and at the meeting part 12, Ll#L2
Form it so that it becomes. Note that "substantially equivalent" here includes the same value and the values before and after the same value.

Next, the effect will be explained.

When this metal gasket 2 is interposed between the cylinder head and cylinder block of an internal combustion engine (not shown) and tightened with a fastening bolt, the bead lO is elastically deformed and forms a seal line on the joint surface to prevent leakage of gas, oil, etc. To prevent.

At this time, the meeting portion 12 of the bead 10 has a bead width L
1 is formed to be approximately equal to the bead width L2 of the non-meeting portion 14, so the spring constant of the meeting portion 12 does not become smaller than that of the non-meeting portion 14. As a result, meeting section 1
It is possible to avoid the decrease in the sealing pressure described in No. 2, and it is possible to prevent leakage of gas, oil, etc. Furthermore, since the sealing pressure exerted on the joint surfaces is not uneven, there is no need to apply excessive fastening force to ensure the sealing performance of the meeting part 12, and this prevents bead breakage and provides effective sealing. can be accomplished.

In this embodiment, a single-plate metal gasket has been described, but it is obvious that the present invention can also be applied to a metal gasket made of a plurality of substrates or a laminated metal gasket made of sub-plates laminated.

〔Effect of the invention〕

As described above, according to the present invention, since the bead width of the meeting part of the beads sealing each sealing part is formed to be approximately equal to the bead width of the non-meeting part, The spring constant of the part will not become small. For this reason,
It is possible to avoid a decrease in the sealing pressure at the meeting portion, and to prevent leakage of gas, oil, etc. In addition, since it is possible to prevent uneven sealing pressure from being applied to the joint surfaces, there is no need to apply excessive fastening force to ensure the sealing performance of the meeting area, which prevents bead breakage and is effective. It can achieve a great seal.

[Brief explanation of the drawing]

1.2 shows an embodiment of the present invention, FIG. 1 is a plan view of a metal gasket, and FIG. 2 is an enlarged plan view of a main part of the metal gasket. FIG. 3 is an enlarged plan view of essential parts of a conventional metal gasket. In the figure, 2 is a metal gasket, 4 is a substrate, 6 is a combustion chamber hole, 8 is a bolt hole, 10 is a bead, 12 is a meeting part, 1
4 is the non-merging portion, Ll is the bead width of the joining portion 12, and L2 is the bead width of the non-merging portion 14.

Claims (1)

[Claims] In a metal gasket that achieves sealing by forming beads on an elastic metal plate, the bead width of the meeting part of the beads sealing each sealing part provided on the elastic metal plate is formed so as to be approximately equal to the bead width of the non-meeting part. A metal gasket characterized by: