JPS6114606Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a metal gasket for internal combustion engines.
In particular, the present invention relates to a metal gasket for internal combustion engines that seals cylinder bores with severe sealing conditions in two stages and improves the sealing performance of joint surfaces.

Conventionally, in most internal combustion engines, the gasket that seals the joint surface between the cylinder head and the cylinder block is made of asbestos or a plurality of metal plates arranged side by side. In particular, sealing was accomplished by bending the peripheral edge of the gasket on the cylinder bore side to form a grommet-like shape, but such gaskets cannot be expected to have good recovery properties, so they may sag and deteriorate the sealing performance of the joint surfaces. There were some inconveniences that prevented me from performing to my full potential. Therefore, in order to solve this problem, as shown in FIG. 3, the bead 103 formed on the substrate 101 is sandwiched within a grommet shape 110 formed by bending the sub-plate 107. The aim was to improve the sealing performance of the However, since the bead 103 is placed very close to the cylinder bore 102, which is subject to high heat and high pressure, the sealing performance of the bead 103 deteriorates due to the influence of the high heat, that is, the restorability of the bead deteriorates. Moreover, this sealing performance also decreases1
Since it seals only at certain points, it has the disadvantage that it is difficult to completely prevent leaks.

Therefore, in order to eliminate the above-mentioned drawbacks, the purpose of this invention is to form a grommet shape by bending the bore-side peripheral edge of one sub-plate so that it is located on the surface of the other sub-plate, and to form a grommet shape. By arranging the elastic beads formed on the substrate so as to surround the grommet so as to be spaced apart from each other on the outside of this grommet shape, it is possible to prevent the elastic beads formed on the substrate from reducing the elastic restoring force due to the effects of high heat, etc. The object of the present invention is to realize a metal gasket for an internal combustion engine, which can seal a cylinder bore with severe sealing conditions in two stages, and which can improve the sealing performance of a joint surface.

Embodiments of this invention will be described in detail and concretely below based on the drawings. In the figure, the code 1 is
This is a substrate made by punching a hard and elastic metal thin plate such as SK or SUS into a shape that is the same as or similar to the bonding surface. In this substrate 1, an elastic bead 3 having a height corresponding to the required surface pressure surrounds the cylinder bore 2 on the peripheral edge side of the combustion chamber which is subject to high heat and high pressure, that is, on the peripheral edge portion 1a of the substrate 1 on the cylinder bore 2 side. It is formed to suit. Further, the peripheral edge side of the cooling water passage 4 and the oil passage (not shown) which are at low temperature, that is, the peripheral edge 1b of the cooling water passage 4 side of the substrate 1 is also provided so as to surround the cooling water passage 4 and the oil passage, respectively. Elastic bead 5 having a height according to the required surface pressure
is formed.

On the other hand, upper and lower sub-plates 6 and 7 made of metal plates softer than the substrate 1 are disposed on both sides of the substrate 1. These upper and lower sub-plates 6 and 7 also have peripheral edges 6a and 7a on the cylinder bore 2 side, and cooling cooling water, corresponding to the peripheral edge 1a on the cylinder bore 2 side and the peripheral edge 1b on the cooling water passage 4 side of the substrate 1, respectively. Peripheral portions 6b and 7b are formed on the water passage 4 side. Further, the peripheral edge portions 6a and 6b of the upper sub-plate 6 are each formed with a stepped portion 61 so as to be one step lower than the other portions. on the other hand,
The peripheral edges 7a and 7b of the lower sub-plate 7 are bent upwardly into a grommet shape {sections A-1 and A-5 in FIG. They are respectively located on the stepped portions 61 of the upper sub-plate 6. The bent end portion 71 is located closer to the cylinder bore 2 and the cooling water passage 4 than the elastic beads 3 and 5 formed on the substrate 1, that is, the elastic beads 3 and 5 are positioned closer to the cylinder bore 2 and the cooling water passage 4 than the grommet-shaped portion. It is placed on the outside {portions A-2 and A-4 in FIG. 1}.
As a result, the elastic bead 3 in particular is placed apart from the cylinder bore 2 side, which is exposed to high heat, so that the elastic bead 3 is not directly exposed to high heat, etc.
There is no inconvenience that causes deterioration of elastic restoring force. Note that the substrate 1 extends to the lower side of the stepped portion 61 of the upper sub-plate 6 on the cylinder bore 2 side, which is the high temperature side, but on the cooling water passage and oil passage side, which are the low temperature side, it extends to the high temperature side. Since a relatively large surface pressure is not required, the structure is such that it does not extend to the lower side of the stepped portion 61.

Further, between the substrate 1 and the lower sub-plate 7, elastic beads 3 and 5 of the substrate 1 are formed,
Further, a surface pressure plate 8 formed thinner than the thickness of the upper and lower sub-plates 6 and 7 is arranged. This surface pressure plate 8 is
Even when the elastic beads 3 and 5 formed on the substrate 1 are pressed by the fastening force, the elastic beads 3 and 5
5 prevents the elastic restoring force from deteriorating and maintains a large spring constant of the elastic bead.

Because of this structure, cylinder bore 2
The thickness of the peripheral edge part, that is, the grommet-like {A-1}, is the same as that of the other parts {A-2, A-3, A-4, A-
Therefore, the A-1 portion can obtain a very large surface pressure due to the initial tightening pressure of the bolt. Now, to state specific numbers, suppose that the board 1, upper and lower sub-plates 6 and 7 have a thickness of 0.3 mm, and the surface pressure plate 8 has a thickness of 0.2 mm, then A- 1
The plate thickness of the part is 1.2mm, and A-2, A-4, A
The thickness of the -5 part is 0.9mm, and the thickness of the A-3 part is 1.1mm. Therefore, before the bolts are tightened, the overall thickness of the A-1 section is at least 0.1 mm thicker than the other sections. In addition, in the A-2 portion adjacent to the A-1 portion,
A large sealing surface pressure is exerted by the elastic bead 3. As a result, the cylinder bore 2 is sealed with large surface pressure in two stages by the A-1 and A-2 portions. On the other hand, the cooling water passage 4 is connected to A-4 and A-
The five parts seal in two stages with small surface pressure. In other words, cylinder bore 2, which has strict sealing conditions,
The elastic bead 3 on the periphery of is arranged so that the surface pressure increases.
Also, the cooling water passage 4, which has less severe sealing conditions,
The elastic bead 5 on the periphery is formed in accordance with sealing conditions so that the surface pressure is smaller than that of the elastic bead 3. On the other hand, the thickness of the surface pressure plate 8 is determined by, for example, when the upper and lower sub-plates 6 and 7 are made of soft metal such as aluminum, the upper and lower sub-plates 6 and 7 have a bonding surface. Because it absorbs the roughness well and is compressed somewhat after bolt tightening, as mentioned above,
Provide a thickness difference of approximately 0.1 mm between the lower sub-plates 6 and 7. In addition, if the upper and lower sub-plates 6 and 7 are made of a constituent metal such as iron, the amount of compression after bolt tightening will be considerably small, so the above-mentioned 0.1
It is freely selected to be less than mm. However, the thickness of this surface pressure plate 8 is the same as that of the substrate 1.
The thickness is selected so that it is not thicker than the upper and lower sub-plates 6 and 7. In other words, the A-3 portion between the elastic bead 3 and the elastic bead 5 with the surface pressure plate 8 interposed therebetween does not require a large surface pressure, so the thin surface pressure plate 8 is interposed therebetween, and the restoration of the elastic bead is prevented. The amount is maximized without causing deterioration of elastic restoring force.

With this configuration, when assembled between the cylinder head and cylinder block,
The upper and lower sub-plates 6 and 7 are connected to the joint surfaces of the cylinder head and cylinder block without any gaps, and
In the bonded state, the elastic beads 3 and 5 of the substrate 1
The pressing force works well and satisfies the conditions necessary to seal the cylinder bore 2 and cooling water passage 4.

That is, the cylinder bore 2 is sealed at the grommet-shaped portion A-1 and also at the A-2 portion where the elastic bead 3 is arranged, that is, the sealing is achieved in two stages. This results in
The leakage of gas, etc. that could not be solved in the A-1 part,
It is completely blocked by the A-2 part. Further, since the elastic bead 3 is spaced apart from the cylinder bore 2 which is subject to high heat and high pressure, it is not directly exposed to high heat or the like. Therefore, the elastic bead 3 can continue to maintain its large spring constant without causing deterioration of the elastic restoring force. Further, the elastic beads 3 and 5 are elastically deformed within a predetermined range by the surface pressure plate 8, and are not completely deformed into a flat shape. For this reason, the elastic beads 3 and 5 can maintain their elastic restoring force, and there is no fear that the elastic beads 3 and 5 will become sagging, thereby increasing the spring constant of the elastic beads and joining. The surface sealing performance is improved. On the other hand, since the cooling water passage 4 does not require a sealing surface pressure strong enough to seal the cylinder bore 2, it is sealed by the portions A-4 and A-5 where the surface pressure is small.

In addition, FIG. 2 shows another embodiment, in which the elastic beads 3 and 5 of the substrate 1 and the grommet shape are covered, and
Seal materials 9, 9a, 9 in an amount necessary to absorb the roughness of the joint surfaces of the cylinder head and cylinder block and that meet the sealing conditions are applied to the surfaces of the lower sub-plates 6, 7.
b is painted or plated. The thickness of the sealing material 9a applied to the periphery of the cylinder bore 2 on the high temperature side is thinner than the thickness of the sealing material 9b applied to the periphery of the cooling water passage 4 etc. on the low temperature side. This absorbs strain on the joint surface on the cylinder bore 2 side, where sealing conditions are especially severe. With such a configuration, it is more familiar than those of the above-mentioned embodiments, and the sealing performance can be further improved. The rest of the configuration is the same as the configuration of the embodiment described above, so a description thereof will be omitted.

As is clear from the detailed explanation above, according to this invention, a grommet-like part placed around the cylinder bore, which has severe sealing conditions, achieves a certain degree of sealing and absorbs most of the high heat and high pressure generated in the cylinder bore. can be blocked. As a result, the elastic beads arranged at a distance on the outside of the grommet shape are not directly exposed to the high heat, etc., and therefore, the elastic restoring force of the elastic beads is prevented from being reduced by the high heat, etc. This can be reliably prevented. Moreover, since the gas etc. partially leaking from the grommet-like portion is sealed by the elastic bead which prevents the elastic restoring force from decreasing, leakage from the joint surface can be completely prevented. In this way, it is possible to prevent a decrease in the elastic restoring force of the elastic bead, and in addition, sealing can be performed in two stages, and sealing performance can be improved. Furthermore, seal structures can be freely selected to reduce the surface pressure for the peripheral edges of cooling water passages and oil passages where the sealing conditions are not so severe, for example. As a result, the sealing effect can be reliably maintained even in an engine having a structure in which the joint surface shape is complicated and the sealing surface is large.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a metal gasket for an internal combustion engine showing a first embodiment of this invention. FIG. 2 is a sectional view of a metal gasket for an internal combustion engine showing another embodiment of this invention. FIG. 3 is a partial sectional view of a conventional metal gasket. In the figure, 1 is the substrate, 2 is the cylinder bore, and 3
is an elastic bead on the cylinder bore side, 4 is a cooling water passage, 5 is an elastic bead on the cooling water passage side, 6 is an upper sub-plate, 61 is a stepped part, 7 is a lower sub-plate, 71 is an end of a bent part, and 8 is a surface pressure plate.

Claims (1)

[Scope of utility model registration request] In a metal gasket that achieves sealing by providing sub-plates on both sides of a substrate in which elastic beads are formed on an elastic metal plate, the plate thickness is greater than that of the sub-plate between the elastic beads of the substrate and between the substrate and one of the sub-plates. A surface pressure plate selected to be small is interposed, the bore side peripheral edge of one sub-plate is bent to be positioned on the surface of the other sub-plate to form a grommet shape, and the elastic bead surrounding the grommet shape is formed. A metal gasket for an internal combustion engine characterized by being arranged at a distance on the outside of this grommet shape.