JPH0240145B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a metal gasket, and in particular to a metal gasket that compensates for irregularities in the deck surface gap around the combustion chamber that occur during fastening by a compensation portion formed around the combustion chamber hole. The present invention relates to a metal gasket which can prevent deterioration of the sealing effect and achieve stable sealing, can improve the strength of the compensating part to prevent damage, and can extend the service life.

[Conventional technology]

Metal gaskets are used to seal the joining surfaces of members to be joined, for example, the deck surfaces between a cylinder block and a cylinder head of an internal combustion engine. The metal gasket has a bead formed to seal the sealing surface, and this bead is caused by the fastening force of a bolt or the like that joins the members to be joined together.
It is elastically deformed. The bead forms an elastic seal line on the deck surface by the restoring amount and restoring force during this elastic deformation to achieve sealing, and also maintains the sealing effect by following the strain.

Metal gaskets are disclosed, for example, in Japanese Utility Model Application Publication No. 12653/1983 filed by the present applicant. The metal gasket disclosed in Japanese Utility Model Application No. 60-12653 is constructed so that the inner bead surrounding the cylinder bore and the outer bead including the hole bead surrounding the bolt hole do not come into contact with each other in order to prevent bead breakage. There is.

[Problem that the invention seeks to solve]

However, when the cylinder head is fastened to the cylinder block via a metal gasket with a fastening bolt, there is a problem in that the cylinder head is distorted by the fastening force, and the deck surface gap especially around the combustion chamber becomes large.

As a result, combustion gas leaks from the large gap around the combustion chamber due to insufficient pressure of the bead, contaminating the metal gasket interposed between the joining members, and causing the sealing effect to deteriorate due to the accumulation of contained substances. This had the disadvantage of reducing the

Additionally, during use, as the deck surface gap around the combustion chamber increases or decreases due to combustion pressure, an alternating load acts on the bead of the metal gasket, causing it to sag, and this alternating load also acts on the fastening bolts. There is a risk of damaging the bolt or the cylinder head portion with which the bolt engages, and furthermore, there is a disadvantage that the tightening force of the bolt is reduced and the sealing effect of the metal gasket is reduced.

Furthermore, in a metal gasket in which a sub-plate is laminated on a substrate and the edge of the sub-plate on the side of the combustion chamber hole is folded back to form a grommet for sandwiching the edge of the substrate on the side of the combustion chamber hole in the folded space, the gasket can be opened from inside the folded space. There is an inconvenience that combustion gas leaks. Further, when the bolts are fastened, the folded portion of the sub-plate is strongly deformed, and the edge of the substrate on the side of the combustion chamber hole is pushed and collided with the innermost part of the folded-back portion of the sub-plate due to the compressive deformation of the bead. For this reason, the folded part may be damaged, resulting in a decrease in strength, leading to breakage, or the elastic deformation of the bead may be prevented, causing stress exceeding the allowable limit to be applied to the bead, resulting in breakage, resulting in the inconvenience of shortening the service life. Ta.

[Purpose of the invention]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to eliminate the above-mentioned disadvantages, and to compensate for irregularities in the deck surface gap around the combustion chamber that occur during fastening by using a compensating portion formed around the combustion chamber hole of the metal gasket, thereby reducing the fouling of the gasket and the sealing effect. To realize a metal gasket which can prevent a reduction in the amount of gas, achieve stable sealing, improve the strength of a compensating part to prevent damage, prevent bead breakage, and extend its service life. There is a particular thing.

[Means for solving problems]

In order to achieve this object, the present invention provides a sub-plate laminated on a substrate made of an elastic metal plate in which a bead surrounding a combustion chamber hole is formed, and an edge of the sub-plate on the side of the combustion chamber hole is placed on the substrate side. By folding back to form a folded part, a folded space is formed in this folded part, and the edge of the substrate on the side of the combustion chamber hole is included in the folded space, and the edge of the substrate on the side of the combustion chamber hole is formed in the bead. An elastic sealing member is filled in the space to prevent collision with the inner depth of the folded portion due to compressive deformation of the substrate, and the edge of the substrate on the combustion chamber hole side is held, thereby compensating for irregularities in the deck surface gap. The present invention is characterized in that it is provided with a compensation section for compensation.

[Effect]

According to the configuration of the present invention, the compensation portion formed at the periphery of the combustion chamber hole is formed by folding back the combustion chamber hole side edge of the sub-plate laminated on the substrate toward the substrate to form a folded portion. The edge of the combustion chamber hole of the substrate is enclosed within the formed folded space, and an elastic sealing member is filled in the folded space to hold the edge of the substrate on the side of the combustion chamber hole. This prevents leakage from inside the folding space, elastically compensates for the unevenness of the deck surface around the combustion chamber that is formed during fastening, and avoids insufficient pressure contact force of the bead.
In addition, it is possible to seal in two stages: an elastic seal by the compensating section filled with an elastic sealing member and an elastic seal by the beads, thereby preventing the intrusion of combustion gas from the large deck surface gap around the combustion chamber. This prevents the alternating load from acting on the bead, and also prevents strong pressure deformation of the folded part of the secondary plate during fastening and collision of the edge of the combustion chamber hole side of the board deep inside the folded part of the secondary plate. This avoids damage to the folded portion and prevention of elastic deformation of the bead.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail and specifically below based on the drawings.

1 to 3 show embodiments of this invention. In the figure, 2 is a metal gasket;
This metal gasket 2 is constructed of a substrate 4 made of an elastic metal plate and a sub-plate 6 laminated on this substrate 4. A combustion chamber hole 8 is formed in the substrate 4, and a bead 10 surrounding the combustion chamber hole 8 is formed. Further, a plurality of bolt holes 10 are formed in the substrate 4 around the combustion chamber hole 8.

The combustion chamber hole side edge 6a of the sub-plate 6 is folded back toward the substrate 4 side to form a folded portion 6c, thereby forming a folded space 6b within this folded portion 6c, and the combustion chamber hole side edge 6a of the substrate 4 is formed in this space 6b. Chamber side edge 4
Include a. An elastic sealing member 14 is filled in the inner deep part 6d of the folded portion 6c of the sub-plate 6 to prevent the end 4a of the substrate 4 from colliding with the compressive deformation of the bead 10. The combustion chamber hole side edge 4a is held. As a result, a compensating portion 16 having a predetermined thickness t1 is formed at the periphery of the combustion chamber hole 8 of the metal gasket 2 to compensate for the deck surface gap during fastening. The thickness t1 of the compensating portion 16 is formed to be thicker than the thickness t2 of the bead 10 when fastened.

Further, in FIG. 3, 18 and 20 are cylinder heads and cylinder blocks constituting the internal combustion engine, and the metal gasket 2 of the present invention is interposed between the deck surfaces of the cylinder head 18 and the cylinder block 20, as shown in the figure. Tighten with bolts that are not attached. Note that 22 is a combustion chamber, 24 is a piston, and S is a deck surface gap around the combustion chamber 22 between the cylinder head 18 and cylinder block 20.

The operation of this embodiment will be explained below.

The metal gasket 2 interposed at the joint between the cylinder head 18 and the cylinder block 20 is compressed by the bolt fastening force, thereby compressing and deforming the bead 10 of the substrate 4 by reducing its height. Due to this deformation, the bead 10 comes into pressure contact with the deck surfaces of the cylinder head 18 and the cylinder block 20 with a predetermined surface pressure, thereby achieving a seal. When tightening bolts,
As shown in FIG. 3, the cylinder head 18 is bent and distorted, and in particular, there is a problem in that the gap S on the deck surface around the combustion chamber 22 becomes large. However, as described above, the end edge 6a of the sub-plate 6 is folded back to the side of the combustion chamber hole 8 from the bead portion to form a folded-back portion 6c, thereby forming a fold-back space 6b, and the substrate 4 is placed within this fold-back space 6b. The end edge 4a is filled and held with an elastic sealing member 14 to a predetermined thickness.
By forming the compensation part 16 with a thickness t1, the large gap S caused by the distortion of the cylinder head 18 can be elastically compensated for by the thickness t1 of the compensation part 16.

As a result, it is possible to avoid insufficient pressure contact force of the bead 10, and sealing is achieved in two stages: an elastic seal by the compensator 16 filled with the elastic seal member 14 and an elastic seal by the bead 10. Therefore, leakage of combustion gas from the gap S can be prevented.
In addition, the compensator 1 compensates for the alternating load acting on the bead 12.
6, it is possible to prevent the bead 12 from weakening and extend its service life, prevent damage to the fastening bolt and the cylinder head 18 that the bolt engages, and reduce the fastening force of the fastening bolt. It is possible to prevent a decrease in the sealing effect and a decrease in the sealing effect.

In addition, by enclosing the edge 4a of the substrate 4 in the folded portion 6c and filling the elastic sealing member 14 to hold the edge 4a of the substrate 4 on the combustion chamber hole side, the secondary plate can be used when fastening. 6 folded part 6c
Further, when the bead 10 is compressively deformed, the deformation of the edge 4c of the substrate 4 in the direction of the folded part can be absorbed by the elastic sealing member 14, and the folded part 6c of the sub-plate 6 can be inner depth 6d
It is possible to prevent the edge 4a of the substrate 4 from colliding with each other. Therefore, the strength of the compensating part 16 can be improved and damage to the folded part 6c can be prevented, and elastic deformation of the bead 10 can be avoided, thereby preventing damage to the compensating part 16 and cutting of the bead 10. can extend the service life.

〔Effect of the invention〕

As described above, according to the present invention, the edge of the combustion chamber hole side of the sub-plate laminated on the substrate is folded back toward the substrate to form a folded portion, so that the combustion of the substrate is carried out within the folded space formed within the folded portion. The edge on the side of the combustion chamber is enclosed, and an elastic sealing member is filled in this folded space to hold the edge of the combustion chamber on the side of the substrate to form a compensating part to prevent leakage from inside the folded space. This elastically compensates for the unevenness of the deck surface around the combustion chamber that is formed during fastening. Therefore, it is possible to avoid insufficient pressure contact force of the bead, and it is possible to perform sealing in two stages: an elastic seal by the compensating part filled with an elastic sealing member and an elastic seal by the bead. This makes it possible to compensate for irregularities in the deck surface gaps of the cylinder head that occur during fastening, especially around the combustion chamber, and to prevent the leakage of combustion gas, etc. from the large gaps around the combustion chamber.
It is possible to prevent the metal gasket from being contaminated by leaked combustion gas or the like and from reducing the sealing effect due to the accumulation of contained substances. In addition, the alternating load acting on the bead is weakened to prevent the bead from sagging, thereby preventing damage to the fastening bolt and the cylinder head portion that the bolt engages with, and reducing the fastening force of the fastening bolt. This can be prevented and a stable sealing effect can be obtained. Furthermore, by filling the elastic sealing member to hold the edge of the combustion chamber hole side of the substrate, it is possible to prevent the folded portion of the sub-plate body from being deformed under strong pressure during fastening, and the bead is compressively deformed. When this occurs, the elastic sealing member can absorb the deformation of the edge of the combustion chamber hole side of the substrate toward the folded part, and the edge of the combustion chamber hole side of the substrate will impact the innermost part of the folded part of the sub plate. contact can be prevented. Therefore, it is possible to improve the strength of the compensating part and prevent damage, and also to avoid preventing elastic deformation of the bead, thereby preventing damage to the compensating part and cutting of the bead, thereby extending the service life.

[Brief explanation of drawings]

1 to 3 show embodiments of this invention,
Figure 1 is a plan view of the metal gasket, Figure 2 is the top view of the metal gasket.
FIG. 3 is an enlarged cross-sectional view of the main part taken along the - line in the figure, and FIG. 3 is a partially omitted cross-sectional view of the main part when a metal gasket is interposed in the joint. In the figure, 2 is a metal gasket, 4 is a substrate,
6 is a sub-plate, 8 is a combustion chamber hole, 12 is a bead of the board,
14 is a sealing member, 16 is a compensation portion, 18 is a cylinder head, 20 is a cylinder block, 22 is a combustion chamber, and S is a gap.

Claims (1)

[Claims] 1. By laminating and providing a sub-plate on a substrate made of an elastic metal plate with beads surrounding the combustion chamber hole, and folding the edge of the sub-plate on the side of the combustion chamber hole toward the substrate to form a folded part. A folded space is formed within this folded portion, and the edge of the substrate on the side of the combustion chamber hole is contained within this folded space, and the edge of the substrate on the side of the combustion chamber hole is compressed and deformed by the bead to the innermost part of the folded portion. The present invention is characterized in that a compensating section is provided to compensate for irregularities in the deck surface gap by filling the space with an elastic sealing member to hold the edge of the combustion chamber hole side of the substrate so as not to collide with the space. metal gasket.