JPH0477833B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a laminated metal gasket, which has a particularly simple construction, compensates for the gap between the deck surfaces around the combustion chamber, and protects the bead of the substrate. This invention relates to a laminated metal gasket that provides a stable sealing effect.

[Prior Art] A metal gasket is used to seal between the deck surfaces of a cylinder head and a cylinder block of an internal combustion engine.

In a metal gasket, a combustion chamber hole and a bead surrounding the combustion chamber hole are formed on a substrate made of an elastic metal plate, and this bead is elastically deformed by bolt fastening force, and the elastic restoring force and the bead at the time of this elastic deformation are A sealing surface pressure is applied between the respective deck surfaces of the cylinder head and cylinder block by the amount of elastic recovery, thereby achieving a seal between the deck surfaces, and
The sealing effect is maintained by following the distortion of the deck surface.

For example, as a laminated metal gasket,
57-175511 and Japanese Patent Application No. 57-15456. The device described in Utility Model Application No. 57-175511 has the tops of beads formed on two substrates directed in the same direction, and an intermediate plate is interposed between the two substrates as an intermediate structure. This structure increases the elastic restoring amount and elastic restoring force of the bead, compensates for unevenness in the partial sealing surface pressure on the deck surface, and improves sealing performance. In addition, the device described in Japanese Patent Application No. 57-154556 has a sub-board interposed between two boards with a sealant coated on one surface, and one back side of each board is placed on both the front and back sides of the sub-board. The substrates are bonded and stacked so that the beads of the substrates are positioned approximately symmetrically with respect to the sub-plate, and the amount of elastic recovery due to the elasticity of the beads is doubled to improve the sealing effect.

[Problems to be Solved by the Invention] By the way, when a cylinder head is fastened to a cylinder block with a laminated metal gasket interposed therebetween using fastening bolts, the cylinder head may be bent due to the bolt fastening force, for example. In particular, the deck surface gap around the combustion chamber becomes large, which can cause distortion.

Furthermore, during the explosion stroke of an internal combustion engine, the gap between the deck surfaces of the cylinder head and cylinder block expands and contracts. For this reason, combustion gas leaks from the large gap between the deck surfaces around the combustion chamber, and the laminated metal gasket is contaminated by this combustion gas, and the sealing effect is reduced due to the accumulation of substances contained therein. It was hot.

Furthermore, when the internal combustion engine is operating, the gap between the deck surfaces around the combustion chamber expands and contracts due to combustion pressure, which causes an alternating load to act on the bead of the laminated metal gasket, causing it to sag, causing the bead to be pressed down with a width greater than necessary. Repeated shrinking and restoring causes fatigue failure in the bead, shortening its service life, and this alternating load also acts on the fastening bolt, potentially damaging the bolt and the cylinder head part where the bolt engages. Furthermore, there was a problem in that the bolt fastening force was reduced and the sealing effect was reduced.

[Object of the Invention] Therefore, in order to eliminate the above-mentioned disadvantages, an object of the present invention is to provide a first intermediate plate as an intermediate structure between the first substrate and the second substrate to be laminated, and a thickness equal to the thickness of the first intermediate plate. A second intermediate plate having a thickness smaller than that of the second intermediate plate is laminated, and the edge of the first intermediate plate on the combustion chamber hole side is folded back to the surface on which the second intermediate plate is located and joined to the surface. At the same time, the second intermediate plate end face of the second intermediate plate combustion chamber hole side edge of the second intermediate plate is spaced apart from the first intermediate plate end face of the first intermediate plate combustion chamber hole side edge, and the second intermediate plate is provided by laminating the first substrates with the tops of the first beads in contact with each other, and the edge of the first substrate on the combustion chamber hole side, the edge of the second substrate on the combustion chamber hole side, and the edge of the first intermediate plate on the combustion chamber hole side. By joining the edge to the first intermediate plate itself, a compensating portion of a predetermined thickness is provided on the combustion chamber hole side from the bead portion where the first and second beads are located, so that the first intermediate plate is simply By simply folding back the edge of the first intermediate plate on the side of the combustion chamber hole, the area around the combustion chamber is double sealed by the compensation part and the bead part, and the distance between the deck surfaces of the cylinder head and cylinder block is compensated. to prevent expansion and contraction from occurring in this gap,
The objective is to realize a laminated metal gasket that protects the bead of the substrate and provides a stable sealing effect.

[Means for Solving the Problems] In order to achieve this object, the present invention provides a first and second substrates that are stacked so that the first and second beads surrounding the combustion chamber hole are in the same position, In this laminated metal gasket in which an intermediate structure is interposed between the first substrate and the second substrate, a first intermediate plate and the first intermediate plate are disposed between the first substrate and the second substrate as the intermediate structure. A second intermediate plate having a thickness smaller than the plate thickness is stacked, and an edge of the first intermediate plate on the first intermediate plate combustion chamber hole side is folded back to the side where the second intermediate plate is located. and a second intermediate plate end face of the second intermediate plate combustion chamber hole side edge of the second intermediate plate is separated from the first intermediate plate end face of the first intermediate plate combustion chamber hole side edge. and the first substrate is stacked on the second intermediate plate so that the top of the first bead is in contact with the first substrate, and the first substrate combustion chamber hole side edge of the first substrate and the second substrate combustion chamber hole of the second substrate are connected to each other. By joining the side edge of the first intermediate plate, the combustion chamber hole side edge, and the first intermediate plate itself, the first intermediate plate is positioned closer to the combustion chamber hole than the bead portion where the first and second beads are located. is characterized by providing a compensation portion with a predetermined thickness.

[Function] According to the configuration of the present invention, in order to compensate for the deck surface gap between the cylinder head and the cylinder block, a predetermined thickness of the bead provided surrounding the combustion chamber hole is formed on the side of the combustion chamber hole from the bead portion. It forms a compensation part. As a result, the deck surface gap is double sealed by the compensating part and the bead part, and
Compensates for the large deck surface gap around the combustion chamber, prevents the deck surface gap from expanding or contracting due to the effects of combustion gas pressure and engine heat, weakens the effect of alternating loads on the bead, and prevents the bead from sagging. Therefore, the bead of the substrate does not repeat pressing contraction and restoration with an unnecessarily large pressing width, thereby preventing fatigue failure of the bead, protecting the bead, and stabilizing the sealing effect. I can do it.

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

1 to 4 show embodiments of this invention. In the figure, 2 is a laminated metal gasket. This laminated metal gasket 2 includes first and second substrates 4 and 6 made of elastic metal plates with a thickness to, and a first intermediate structure interposed between the first and second substrates 4 and 6. , second intermediate plates 8 and 10.

The first and second substrates 4 and 6 have a combustion chamber hole 12,
A plurality of bolt holes 1 are provided around this combustion chamber hole 12.
4 is formed.

The first intermediate plate 8 has a thickness t1 of the first intermediate plate 8.
A second intermediate plate 10 having a thickness t2 smaller than that is laminated.

The thickness t1 of the first intermediate plate 8 and the thickness t2 of the second intermediate plate 10 constitute an intermediate structure having a thickness H1.

Further, the edge 8 of the first intermediate plate 8 on the combustion chamber hole 12 side
e is folded back to the side where the second intermediate plate 10 is located by bending or the like, and the end edge 10e of the second intermediate plate 10
In other words, the second intermediate plate 10 is spaced a predetermined distance C from the end edge 10e of the second intermediate plate 10 on the combustion chamber hole 12 side, and is joined to the surface thereof. As a result, a thickness H2 larger than the thickness H1 is formed on the combustion chamber hole 12 side by joining the second intermediate plate 10 itself and the end edge 10e of the second intermediate plate 10.

First and second substrates 4 and 6 are provided on both surfaces of the laminated first intermediate plate 8 and second intermediate plate 10 so as to sandwich the first and second substrates 8 and 10 therebetween.

That is, the end edge 8e of the first intermediate plate 8 is placed on the second intermediate plate 10 on the side where the end edge 8e of the first intermediate plate 8 is folded back.
A first substrate 4 on which a first bead 16 is formed so as to surround the first substrate 4 is laminated. This first substrate 4
The top of the bead 16 is disposed in contact with the second intermediate plate 10 surface.

On the other hand, a second bead 18 is attached to the first intermediate plate 8 on the opposite side where the end edge 8e of the first intermediate plate 8 is folded back.
The second substrate 6 is laminated at the same position as the bead 16. The second substrate 6 is provided such that both bases of the second beads 18 are in contact with the first intermediate plate 6 and the tops thereof protrude outward. Therefore, the first bead 16 of the first substrate 4
and the second bead 18 of the second substrate 6 have their tops oriented in the same direction and located at the same position. The bead portion 2 of the laminated metal gasket 2 is located at the location where the first bead 16 and the second bead 18 are located.
0 is formed.

Further, the combustion chamber hole 12
On the side, the thickness to of the edge 4e of the first substrate 4, the thickness t1 of the first intermediate plate 8 itself, and the edge 8e of the first intermediate plate 8.
The compensation portion 22 of the laminated metal gasket 2 is formed by the thickness t1 of the second substrate 6 and the thickness to of the edge 6e of the second substrate 6. In other words, as shown in FIG. 3, the compensation portion 22 is formed to have a thickness H3 greater than other portions when bolted. The compensation portion 22 having the thickness H3 compensates for the deck surface gap around the combustion chamber hole 12, prevents the deck surface gap from expanding or contracting, and prevents the first and second beads 16 and 18 from fully bending. It is intended to prevent

The first and second substrates 4 and 6 and the first and second intermediate plates 8 and 10 are, for example, extended and overlapped at their respective outer edges, and a hole is formed in the overlapped portion. The first substrate 4 or the second substrate 6 is held integrally by inserting a rivet or the like and caulking it, or by folding the outer edge of the first substrate 4 or the second substrate 6 and overlapping and locking it with the other substrate.

Further, in FIGS. 3 and 4, 24 and 26 are cylinder heads and cylinder blocks constituting the internal combustion engine, and the deck surface 2 of the cylinder head 24 is
A laminated metal gasket 2 is interposed at the joint 28 between the cylinder block 4d and the deck surface 26d of the cylinder block 26,
It is fastened with a fastening bolt 30. In addition, the code 3
2 is a combustion chamber, 34 is a piston, and S is a deck surface gap between the cylinder head 24 and cylinder block 26 on the combustion chamber side.

Next, the operation of this embodiment will be explained.

As shown in FIG. 3, the laminated metal gasket 2 interposed at the joint 28 between the cylinder head 24 and the cylinder block 26 is compressed by the fastening force of the fastening bolt 30, and thereby the first and second beads 16 , 18 are compressed and deformed to reduce their height. Due to this deformation, the first and second beads 16, 18 apply a predetermined sealing surface pressure to the deck surfaces 24d, 26d of the cylinder head 24 and cylinder block 26, thereby achieving sealing.

When the fastening bolts 30 are fastened, as shown in FIG. 4, for example, the cylinder head 24 is bent and distorted, and in particular, there is a problem that the gap S between the deck surfaces around the combustion chamber 32 becomes large.

However, as described above, by providing the compensating section 22 with a predetermined thickness on the side of the combustion chamber hole 12 rather than the bead section 20, the thickness of the compensating section 22 can greatly reduce the distortion caused by the cylinder head 24. The gap S can be compensated for. This makes it possible to prevent combustion gas from leaking from the gap S.
In addition, the compensator 22 prevents the deck surface gap from expanding or contracting due to the influence of combustion gas pressure or engine heat, and reduces the alternating load acting on the first and second beads 16 and 18.
The first and second beads 16, 18 are weakened by
Prevents sagging. In other words, the first and second beads 16 and 18 are protected by preventing the bead from undergoing fatigue failure due to repeated pressing contraction and restoration with a pressing width greater than necessary. In addition, it is possible to prevent damage to the fastening bolt 30 and the part of the cylinder head 24 that the fastening bolt 30 engages with, as well as to prevent a decrease in the fastening force of the fastening bolt 30, and with a stable sealing effect, the service life can be extended. It can be made longer.

Further, according to this embodiment, since the first and second substrates 4 and 6 are provided so as to sandwich the laminated first intermediate plate 8 and second intermediate plate 10, the bead portion 2
0 elastic restoring amount and elastic restoring force are increased, and the sealing effect of the bead portion 20 is improved. Therefore,
Since the area around the combustion chamber 32 is sealed at two places, the compensating part 22 and the sealing part 20, an even higher sealing effect can be obtained, and leakage of combustion gas can be efficiently prevented.

Furthermore, the bead portion 20 of the laminated metal gasket 2
The thickness of the compensating portion 22 is the thickness t1 of the first intermediate plate 8.
and/or can be changed by changing the plate thickness t2 of the second intermediate plate 10, and the sealing surface pressure applied to the deck surface can be easily changed as desired by changing the thickness of the compensation part 22. Can be set.

Furthermore, the compensation section 22 can be constructed by simply folding back the end edge 8e of the first intermediate plate 8, resulting in a simple construction.

Note that this invention is not limited to the above-mentioned embodiments,
Of course, various applications and modifications are possible.

For example, in the above embodiment, the compensation section is
The edge of the intermediate plate on the combustion chamber hole side was folded back, but in order to adjust the thickness of the compensation part, plating, thermal spraying, painting, etc. were applied, or the metal crotch was made of a material such as heat-resistant resin. It is possible to provide

Further, the increased thickness of the compensating portion can be formed by fixing the compensating member to the deck surface of the cylinder head or cylinder block, or by interposing the compensating member between the deck surface and the substrate.

Furthermore, the thickness of the compensating part may not be formed all around the combustion chamber, but may be provided partially around the combustion chamber as desired. Thereby, for example, point contact is made at the bolt fastening site, while line contact is made at a location away from the bolt fastening site, thereby ensuring sealing performance.

Furthermore, it is also possible to make the thickness of the compensating portion smaller, for example, at the bolt fastening site, while increasing it at a location spaced apart from the bolt fastening site, thereby making the sealing surface uniform and improving the sealing performance.

In addition, the two substrates were arranged with the tops of the beads oriented in the same direction, but the tops of the beads with different bead widths were arranged in a symmetrical shape with respect to the opposing surface, respectively, in contact with the intermediate plate. It is also possible to do so.

Furthermore, it is also possible to apply a plating layer or a sealing material to the front and back surfaces of the laminated metal gasket, that is, the surface of the first substrate and the surface of the second substrate, to compensate for irregularities such as tool marks on the deck surface.

Furthermore, it is also possible to change the width and height of the first and second beads depending on the deck surface gap.

[Effects of the Invention] As is clear from the above detailed description, according to the present invention, there is a first intermediate plate as an intermediate structure between the first substrate and the second substrate, and a thickness smaller than that of the first intermediate plate. A second intermediate plate having a thickness of A second intermediate plate end face of the second intermediate plate combustion chamber hole side edge of the second intermediate plate is spaced apart from a first intermediate plate end face of the first intermediate plate combustion chamber hole side edge, and the second intermediate plate has a first intermediate plate end face of the second intermediate plate combustion chamber hole side edge. A first substrate is stacked with the tops of one bead in contact with each other, and an edge of the first substrate on the combustion chamber hole side, an edge of the second substrate on the combustion chamber hole side, and an edge of the first intermediate plate on the combustion chamber hole side. By joining the first intermediate plate and the first intermediate plate itself, the first and second
By providing a compensation portion with a predetermined thickness on the combustion chamber hole side of the bead portion where the bead is located, the combustion chamber can be adjusted by simply folding back the edge of the first intermediate plate on the combustion chamber hole side. The circumference is double-sealed by the compensating part and the bead part, and the gap between the deck surfaces of the cylinder head and cylinder block is compensated to prevent expansion and contraction of this gap, thereby protecting the bead of the board. , obtain a stable sealing effect.

[Brief explanation of the drawing]

1 to 4 show embodiments of the present invention, FIG. 1 is a plan view of a laminated metal gasket, FIG. The figure is a partially omitted sectional view of a main part of a state in which a laminated metal gasket is interposed in a joint portion. In the figure, 2 is a laminated metal gasket, 4 is a first substrate, 6 is a second substrate, 8 is a first intermediate plate, 10 is a second intermediate plate, 12 is a combustion chamber hole, 16 is a first bead, and 18 is a first 2 beads, 20 is a bead portion, and 22 is a compensation portion.

Claims (1)

[Claims] 1. A laminated metal gasket in which a first and a second substrate are stacked so that the first and second beads surrounding the combustion chamber hole are in the same position, and an intermediate structure is interposed between the first substrate and the second substrate. A first intermediate plate and a second intermediate plate having a thickness smaller than that of the first intermediate plate are stacked and provided as the intermediate structure between the first substrate and the second substrate, The first intermediate plate combustion chamber hole side edge of the first intermediate plate is folded back toward the surface where the second intermediate plate is located and joined to the surface, and the first intermediate plate
A second intermediate plate end face of the second intermediate plate combustion chamber hole side edge of the second intermediate plate is spaced apart from a first intermediate plate end face of the intermediate plate combustion chamber hole side edge, and the second intermediate plate The first substrates are stacked so that the tops of the first beads are in contact with each other, and an edge of the first substrate on the combustion chamber hole side, an edge of the second substrate on the combustion chamber hole side of the second substrate, and the first intermediate plate. By joining the combustion chamber hole side edge and the first intermediate plate itself, a compensation portion having a predetermined thickness is provided closer to the combustion chamber hole than the bead portion where the first and second beads are located. A laminated metal gasket characterized by: