JPH026380B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to metal gaskets, and in particular, prevents damage to the mating surface, which is the mating surface, due to the pressing force of the bead, and evens out the surface pressure on the front and back surfaces of the metal gasket. The present invention relates to a metal gasket that can provide an effective seal over a wide area.

The inventor of this application has developed a metal gasket in which a convex or step-like bead is formed on an elastic metal plate, and the bead effectively seals a joint between a cylinder head and a cylinder block of an internal combustion engine, for example. has already been completed and filed. This metal gasket is constructed by laminating a substrate made of an elastic metal plate and sub-plates provided on both the front and back surfaces of this substrate into a single plate, and the deck surface is joined by the bolt tightening force of the cylinder head and cylinder block. It has already been made public that a seal line is formed on the surface to ensure close contact and achieve an outstanding sealing effect.

In addition, as a metal gasket, for example, Jikosho
It is disclosed in Japanese Utility Model Application Publication No. 57-1174 and Japanese Utility Model Application Publication No. 55-24539. In the method described in Japanese Utility Model Publication No. 57-1174, an upper plate and a middle plate are laminated on one side of the substrate on which the bead is formed, and the ends of the lower plate connected to the edge are overlapped at the bead area. ,Also,
On the other side of the board, a lower board and a middle board are laminated,
Moreover, a through hole for adjusting the tightening surface pressure is formed in the other intermediate plate between the upper plate and the intermediate plate. Also, in 1987,
In the method described in Publication No. 24539, the shape of the bead is narrow and steep at the fastening site, wide and at a gentle angle between each fastening site, and the film is fixed to the substrate surface. This is what I did.

However, in the metal gasket described in the above-mentioned Japanese Utility Model Publication No. 57-1174, the top of the bead has a small curvature and the end rises steeply. Since the end portion and the end portion of the lower plate overlap, the surface pressure acting on the joint surface on the top side of the bead acts on the joint surface on the end side of the bead where the middle plate and the lower plate are laminated. It is difficult to equalize the surface pressure on the front and back sides of the metal gasket, and there is no description of the materials of the upper and lower plates that contact each joint surface, and there are no differences in the level of the upper plate or Since the end of the lower plate is in direct contact with the joining surface, there is a risk that the joining surface may be damaged by the stepped portion of the upper board or the end of the lower board.

In addition, the device described in the above-mentioned Japanese Utility Model Publication No. 55-24539 changes the width and angle of the bead in order to equalize the surface pressure of the fastened portion and the surface pressure between each fastened portion. However, there is no mention of any technical concept for appropriately selecting the number of laminated width plates in accordance with the shape of the bead, and as a result, the surface pressures on the front and back sides of the metal gasket are different.

If the surface pressure on the front and back sides of the metal gasket differs in this way, there is a risk that the joint surface will be damaged in areas where the surface pressure is locally strong due to the pressing force of the bead, and the seal line formed by the bead may be damaged on the joint surface. The strength of the applied surface pressure is significantly uneven depending on the location, and this creates gaps in the joints, causing leaks from these gaps and inconveniently preventing a sufficient seal from being achieved on all sides of the bead. occured.

SUMMARY OF THE INVENTION In order to eliminate the above-mentioned disadvantages, it is an object of the present invention to prevent damage to the joint surfaces of the cylinder head and cylinder block, which are the mating surfaces of the metal gasket, and to equalize the surface pressure on the front and back surfaces of the metal gasket. The object of the present invention is to realize a metal gasket that can effectively seal all sides of the bead.

In order to achieve this object, the present invention provides a metal gasket in which a convex bead surrounding a sealing hole is provided on a substrate made of an elastic metal plate to achieve sealing, in which the top of the bead has a large curvature and the bead has a large curvature. The rise of each end of the bead is formed to be small, and the surface pressure applied by the bead to the bonding surface is distributed to one surface of the top side of the bead formed on the substrate, so that the surface pressure on the bonding surface is approximately the same as that of the other surface of the substrate. Two sub-plates are arranged to apply a surface pressure of 1 to one side of the substrate, and the auxiliary plate on at least the outer side of the two sub-plates is applied to the bonding surface by the pressing force of the bead. In order to prevent the bead from being damaged, the bead is formed of a plate material softer than the substrate, and one sub-plate made of a plate material softer than the substrate is placed on the other side of the end side of the bead formed on the substrate. It is characterized by having been placed.

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

In FIG. 1, 2 is a metal gasket.
This metal gasket 2 includes a substrate 6 made of an elastic metal plate on which beads 4 are formed, and a first sub-plate 8 disposed on one side of the substrate 6, and a second sub-plate 10 disposed on the other side of the substrate 6. , the third sub-plate 12 is laminated. The first sub-plate 8 and the third sub-plate 12 are formed from a plate material that is softer than the substrate 6, and a sealing material 14 is applied to the outer surface of each of the first sub-plate 8 and the third sub-plate 12. Ru. The metal gasket 2 is interposed at the joint 20 between the joint surface of the cylinder head 16 and the joint surface of the cylinder block 18 in order to achieve a sealing effect. Note that 19 is an oil passage, 21 is a cylinder hole, and 23 is a bolt hole.

FIG. 2 shows a first embodiment of the invention.

The top 24 of the bead 4 has a small curvature, whereas the ends 26, 26 of the bead 4 rise sharply.

A first sub-plate 8 is disposed on the front side 6a of the substrate 6 from which the tops 24 of the beads 4 project, and a sealing material 14 is applied to the front side 8a of the first sub-plate 8. A second sub-plate 10 and a third sub-plate 12 are provided on the back side 6b of the substrate 6.
are provided by laminating them respectively, and the back side 12 of the third sub-plate 12 is
A sealing material 14 is applied to b. The first sub-plate 8 and the third sub-plate 12 are formed from a plate material that is softer than the substrate 6.

Next, the operation of this first embodiment will be explained.

As shown in FIG. 2, the metal gasket 2 interposed in the joint 20 between the joint surface of the cylinder head 16 and the joint surface of the cylinder block 18 is compressed and deformed by the bolt tightening force, and the metal gasket 2 form a seal line. Due to the restoring force of bead 4,
Surface pressure on the top 24 side of the bead 4 acts on the cylinder head 16 side via the first sub-plate 8. at the same time,
The bolt fastening force causes the ends 26, 26 of the bead 4 to act on the joint surface of the surface pressure cylinder block 18 via the second sub-plate 10 and the third sub-plate 12. and,
Due to the surface pressure caused by the seal line, the metal gasket is brought into close contact with the mating surface, which is the mating surface, thereby preventing leakage.

In this first embodiment, the top 2 of the bead 4
4 has a small curvature and the ends 26, 26 of the bead 4 rise sharply. Therefore, when the bead 4 is compressed and deformed during bolt tightening, the contact area between the top 24 of the bead 4 and the first sub-plate 8 is While the contact area is large, the contact area between the ends 26, 26 of the bead 4 and the second sub-plate 10 is small. Therefore, the surface pressure generated at the contact portion between the bead 4, the first sub-plate 8, and the second sub-plate 10 due to the restoring force of the bead 4 is small on the first sub-plate 8 side, and is small on the second sub-plate 10 side. Then it gets bigger. However, in the first embodiment of the present invention, the third sub-plate 12 is provided on the back side of the second sub-plate 10.
Due to the lamination of the metal gaskets, strong surface pressure is generated locally on the second sub-plate 12, but due to the presence of the third sub-plate 12, the large surface pressure is locally dispersed, and the metal gasket When surface pressure acts on the joint surface of the cylinder block 18, which is the mating surface of the metal gasket 2, this locally large surface pressure is reduced, and the surface pressures on the front and back surfaces of the metal gasket 2 are averaged. This prevents damage to the joint surfaces and also prevents gaps from forming at the joint, thereby providing a long-term sealing effect.

FIG. 3 shows a second embodiment of the invention. In the following embodiments, parts having the same functions as those in the above-described first embodiment will be described with the same reference numerals.

This second embodiment is characterized by the following points. That is, while the top portion 24 of the bead 4 has a large curvature, the end portions 26 are formed to rise gently, that is, to be small, and the bead 4 has a large curvature.
On one side of the top 24 side of the board, there are two first plates in order to disperse the contact pressure on the bonding surface due to the bead 4 and apply substantially the same contact pressure to the other side of the board as on the other side of the board. , a third sub-plate 8, 12 is provided, and these two first and third sub-plates 8, 12 are placed at a position lower than the substrate 6 in order to prevent the bonding surface from being damaged by the pressing force of the bead 4. A first sub-plate 8 made of a softer plate material than the substrate 6 is disposed on the other side of the end side of the bead 4 formed on the substrate 6, and has a first width. Seal materials 14, 14 are applied to the outer surface of the plate 8 and the outer surface of the third sub-plate 12, respectively.

According to the configuration of this second embodiment, the curvature of the top portion 24 of the bead 4 is large, and the end portion 24 of the bead 4 has a large curvature.
6 and 26 have a small rise, so when the bolts are fastened, the contact area between the top 24 of the bead 4 and the second sub-plate 10 is small, whereas the contact area between the bead ends 26 and the first sub-plate 8 is small. are in smooth contact,
The surface pressure generated by the restoring force of the bead 4 at the contact area between the bead 4, the first width plate 8, and the second width plate 10 is smaller on the first width plate 8, but is smaller on the second width plate 10. It becomes locally large. However, in this second embodiment, by disposing the third sub-plate 12 on the front side of the second sub-plate 10, the second sub-plate 10
The locally strong surface pressure generated on the third sub-plate 12
When the contact pressure is transmitted to the cylinder head 16, which is the other side of the metal gasket 2, it decreases, and the contact pressures on the front and back sides of the metal gasket 2 are averaged. This prevents damage to the joint surfaces and reliably prevents gaps from forming in the joint, thereby extending the service life.

FIG. 4 shows a third embodiment of the invention.

This third embodiment is characterized by the following points. Instead of the bead 4 having a curved surface with a convex cross section in the first embodiment shown in FIG. 2, the bead 4 is formed into a curved surface with a stepped cross section. As shown in FIG. 4, the first bent portion 28 of the bead 4 rises more abruptly than the second bent portion 30.

According to the configuration of the third embodiment, the first bent portion 28 of the bead 4 rises abruptly, and the second bent portion 30 rises gently. The contact area between the portion 28 and the second sub-plate 10 is large, and the contact area between the second bent portion 30 and the first sub-plate 8 is large.
The contact area becomes smaller. As a result, the surface pressure generated on the first sub-plate 8 and the second sub-plate 10 due to the restoring force of the bead 4 is small on the first sub-plate 8, and is small on the second sub-plate 8.
It becomes locally large on the sub-plate 10. As a result,
As in the first embodiment, by disposing the third sub-plate 12 on the back side of the second sub-plate 10, the surface pressure transmitted to the cylinder block 18 is reduced and averaged.

In addition, in this third embodiment, when the rise of the first bending part 28 is large and the rise of the second bending part 30 is small, two sub-plates are arranged on the front side of the board 6, It is also possible to have a configuration in which one sub-plate is disposed on the back side of the substrate 6.

As is clear from the above detailed explanation, according to the present invention, when the surface pressure generated by the pressing force of the bead is locally too strong, the provision of two sub-plates allows the surface pressure to be locally concentrated. Since the pressure can be reduced and averaged on the mating surface of the metal gasket, damage to the mating surface of the metal gasket can be prevented. In addition, since it is possible to prevent local concentration of surface pressure due to the bead, the surface pressure on the front and back sides of the metal gasket is approximately uniform and equal, preventing gaps from forming at the joint, and improving the sealing effect of the metal gasket. . Furthermore, since the hardness of the sub-plate that contacts the mating surface is softer than that of the substrate, it is possible to compensate for thermal distortion, tool marks, scratches, etc. on the joint surface, and a good micro-sealing effect can be achieved.

[Brief explanation of drawings]

1 and 2 show a first embodiment of the present invention, in which FIG. 1 is a partially cutaway plan view of a metal gasket, and FIG. 2 is an enlarged sectional view of the metal gasket taken along the line - in FIG. 1. FIG. 3 shows a second embodiment of the invention, and is an enlarged sectional view of a metal gasket. Fourth
The figure shows a third embodiment of the invention, and is an enlarged sectional view of a metal gasket. In the figure, 2 is a metal gasket, 4 is a bead, 6 is a substrate, 8 is a first sub-plate, 10 is a second sub-plate,
12 is a third sub-plate, 14 is a sealing material, 16 is a cylinder head, 18 is a cylinder block, and 20
is the joint.

Claims (1)

[Claims] 1. In a metal gasket that achieves sealing by providing a convex bead surrounding a sealing hole on a substrate made of an elastic metal plate, the curvature of the top of the bead is formed to be large, and the rise of each end of the bead is formed to be small. The surface pressure on the bonding surface due to the bead is distributed to one surface on the top side of the bead formed on the substrate, and the surface pressure on the bonding surface is approximately the same as that on the other surface of the substrate. Two sub-plates are disposed to act on the sides, and at least the outer sub-plates of the two sub-plates are attached to the substrate in order to prevent the bonding surface from being damaged by the pressing force of the bead. A metal gasket characterized in that it is formed of a plate material softer than the substrate, and a sub-plate made of a plate material softer than the substrate is disposed on the other side of the end side of the bead formed on the substrate. .