JPH026381B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a metal gasket, and in particular, a bead formed on an elastic metal plate makes the linear pressure of two seal lines formed on the same surface different, thereby making it more effective. It relates to a metal gasket that performs a seal.

The inventor of this application has developed a metal gasket in which a convex or step-shaped bead is formed on an elastic metal plate, and the bead effectively seals the joint surface between, for example, a cylinder head and a cylinder block of an internal combustion engine. 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 disclosed that a seal line is formed on the surface to ensure close contact and achieve an outstanding sealing effect. As such a metal gasket,
There is one disclosed in Japanese Utility Model Application Publication No. 57-18744. The metal gasket disclosed in this publication has a height of a convex chevron-shaped bead formed surrounding a cooling water passage in a low-temperature section relative to a height of a bead formed in a convex chevron-shaped shape surrounding a combustion chamber in a high-temperature section. Height ratio, 25-90
It is set as low as %.

However, the metal gasket disclosed in this publication is
Since the bead is formed into a symmetrical convex chevron shape, the linear pressure of each of the two seal lines formed by both base ends of the convex bead corresponding to the base of the chevron is equal to the pressure at the top of the chevron. The linear pressure is approximately half of the linear pressure of one seal line formed by the top of the corresponding convex bead. For this reason, depending on the linear pressure of the two seal lines formed by both the base ends, leakage from the base end side may not be completely prevented in some cases.

In addition, in order to completely prevent leakage from the base end side of the symmetrical chevron-shaped convex bead, it is sufficient to increase the linear pressure of the seal line formed on the base end side.
When the linear pressure of the seal line on the proximal side is increased, the amount of increase in the linear pressure on the seal line formed on the top side is This was approximately twice the amount of increase, and not only did the linear pressure on the top side become higher than necessary, but there was also a risk that the joint surface on the top side would be damaged due to the excessively high linear pressure.

SUMMARY OF THE INVENTION In order to eliminate the above-mentioned disadvantages, an object of the present invention is to provide a metal gasket in which a convex chevron-shaped bead is formed on an elastic metal plate to effect a seal, in which two sealing lines formed on the same surface by the bead are provided. By forming the bead into an asymmetrical chevron-shaped convex shape so that the linear pressure of the high-voltage side seal line is higher than that of the low-voltage side seal line, the linear pressure of the high-voltage side seal line and the low-voltage side seal line can be increased. The goal is to create a metal gasket that reliably prevents leaks in conjunction with small linear pressure and does not damage the joint surfaces.

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

2 is a metal gasket, and this metal gasket 2
is composed of a substrate 6 made of an elastic metal plate on which beads 4 are curved, and two sub-plates 8 provided on both sides of the substrate 6. Although the sub-plates 8 are provided on both sides of the substrate 6 in the embodiment, the present invention is not limited to this, and it goes without saying that the sub-plates 8 may not be provided, for example.

This metal gasket 2 is interposed on the joint surface 14 between the cylinder head 10 and cylinder block 12 to achieve a sealing effect. For this reason, a sealing material 16 is applied to the surface of the sub-plate 8 which is directly connected to the cylinder head 10 and cylinder block 12. When the sub-plate 8 is not provided, the sealing material 16 adheres to the substrate 6. In addition,
18 is a cylinder hole, 20 is an oil passage, and 22 is a bolt hole.

By the way, the bead 4 formed curved on the substrate 6
For example, some have shapes shown in FIGS. 2 to 4. In the first embodiment shown in FIG. 2, the bead 4 has an asymmetrical convex chevron shape, including a top portion 4a, a high-pressure side base end portion 4b-1, and a low-pressure side base end portion 4b-2.
It is composed of The top portion 4a forms one seal line on one of the two sub-plates 8, 8-1. Both base end portions 4b form two seal lines on the same surface of the sub-plate 8-1 and the separate sub-plate 8-2, and the high-pressure side base end portion 4b-1 is formed on the high-pressure side. It is a sealed wire, and the base end portion 4b-2 on the low pressure side
is a seal line formed on the low pressure side. Incidentally, the top portion 4a is eccentric toward the high-pressure side base end portion 4b-1. Therefore, due to the balance of forces, the linear pressure at the high-pressure side proximal end 4b-1 is lower than that at the low-pressure side proximal end 4b-2.
It becomes larger compared to the linear pressure of In other words, the linear pressure increases.

In the second embodiment shown in FIG. 3, two top portions 4a of the first embodiment are formed, and the sub-plate 8-
Two seal lines are formed on the same surface of 1, and the high-pressure side top part 4a-1 is formed on the high-pressure side and the low-pressure side top part 4a-2 is formed on the low-pressure side. Other than this, the structure is the same as that of the first embodiment, and both the top portions 4a-1 and 4a-2 are eccentric to the high pressure side.

In the third embodiment shown in FIG. 4, a convex high-pressure side sub-top part 4c-1 and a low-pressure side top part 4a are provided between the high-pressure side top part 4a-1 and the high-pressure side base end part 4b-1 of the second embodiment. A convex low-pressure side sub-top portion 4c-2 is formed in a curved manner between the low-pressure side base end portion 4b-2 and the low-pressure side base end portion 4b-2. Other than this, the configuration is similar to that of the second embodiment.

In the first to third embodiments described above, in order to increase the linear pressure of the top part 4a-1 and the base end part 4b-1 on the high-pressure side, the top part 4a is made eccentric to the high-pressure side. The present invention is not limited to this, and broadly includes cases where the linear pressure on the high voltage side can be made higher than the linear pressure on the low voltage side without eccentricity. For example, bead 4
The linear pressure on the high voltage side can be changed to the linear pressure on the low voltage side by changing the thickness of the substrate 6 on which the 3-dimensional pressure is formed, or by changing the elastic state by heat treatment etc. even if the thickness is the same. It is possible to make it relatively high.

Since this invention is configured as described above,
It works as follows.

A metal gasket 2 interposed in the joint surface 14 between the cylinder head 10 and the cylinder block 12
The metal gasket 2 is compressed by the bolt tightening force, and the top 4a (or 4a-1) of the bead 4 is compressed.
and 4a-2) are gently curved surfaces, and due to this fastening force, linear pressure from the seal line acts on the cylinder head 10 side. At the same time, this fastening force
Both end portions 4b-1 and 4b-2 of the bead 4 apply linear pressure to the cylinder block 12 side by a seal line.

At this time, in the first embodiment, the linear pressure at the high-voltage side proximal end 4b-1 is always higher than the linear pressure at the low-voltage side proximal end 4b-2, that is, the linear pressure is higher, so normally Leakage prevention is sufficiently achieved by the linear pressure between the high-pressure side base end 4b-1 and the top 4a. However, sometimes the high-pressure side proximal end 4b- is always smaller than the linear pressure of the top 4a which is equal to the sum of the linear pressures of both the proximal ends 4b-1 and 4b-2.
1, oil, gas, etc. may leak, but since the amount of oil, gas, etc. is small when leaking from the high pressure side base end 4b-1 having high linear pressure, In the space 4d formed between the parts 4b-1 and 4b-2, the leaked oil, gas, etc. expands sufficiently and the pressure decreases, so the low line of the low pressure side proximal end 4b-2 Leak prevention is reliably achieved even under pressure. By the way, in the conventional case, the linear pressure at the base end located on the high pressure side is not very high, so when leaking from this base end, the rate at which oil, gas, etc. is depressurized is as follows in the case of the present invention. Since the pressure of the oil, gas, etc. does not drop much in the space 4d, and as a result, it leaks from the base end located on the low pressure side.

On the other hand, in the configurations of the second and third embodiments, the same situation as in the above-described first embodiment occurs also in the high-pressure side top portion 4a-1 and the low-pressure side top portion 4a-2. In addition, in the configuration of the third embodiment, since the sub-top portion 4c is formed, it is more flexible than the configurations of the first and second embodiments, and there are tool marks, scratches, etc. on the joint surface 14. Even in such a case, these factors can be compensated for and sufficient adhesion to the joint surface 14 can be achieved, and leakage prevention can be reliably achieved.

As is clear from the above description, according to the configuration of the present invention, not only can leakage of oil, gas, etc. under high pressure be prevented by using the high-pressure side seal line with a large linear pressure, but also the leakage of oil, gas, etc. Even if there is a leak from the high-pressure side seal line, the oil, gas, etc. under high pressure will be depressurized using a large line pressure, and the leaked oil, gas, etc. will be reliably contained in the low-pressure side seal line. It prevents leakage and always achieves a stable sealing effect. Furthermore, when one side is formed by a single seal line, the linear pressure of this single seal line is the sum of the large linear pressure of the high-voltage seal line and the small linear pressure of the low-voltage seal line, so The linear pressure of the one sealed wire mentioned above is not much higher than the linear pressure of the high pressure side sealed wire.
Therefore, there is little risk of damaging the bonding surface on the side of the single seal line, resulting in extremely novel effects.

[Brief explanation of drawings]

The drawings show embodiments of the invention,
Figure 1 is a partially cutaway plan view of the metal gasket;
Figures to Figures 4 are enlarged views of the main parts of Figure 1 with the - section partially omitted; Figure 2 shows the first embodiment, Figure 3 shows the second embodiment, and Figure 4 shows the third embodiment. represent In the figure, 2 is a metal gasket, 4 is a bead, 4a
-1 is the top of the high pressure side, 4a-2 is the top of the low pressure side, 4b
-1 is the base end on the high pressure side, 4b-2 is the base end on the low pressure side,
4c-1 is a high-pressure side sub-top, 4c-2 is a low-pressure side sub-top, 4d is a space, 6 is a substrate, 8 is a sub-plate, 10 is a cylinder head, 12 is a cylinder block, 14
is a joint surface, 16 is a sealing material, 18 is a cylinder hole,
20 is an oil passage, and 22 is a bolt hole.

Claims (1)

[Claims] 1. In a metal gasket that achieves sealing by forming a convex chevron-shaped bead on an elastic metal plate, the line of the high-pressure side seal line of the two seal lines formed on the same surface by the bead is the line of the low-pressure side seal line. A metal gasket characterized in that the bead is formed into an asymmetrical chevron-shaped convex shape so as to be larger than the pressure.