JPH026379B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to the improvement of metal gaskets, and in particular, to improve the irregularity of the joint surface caused by non-uniform thermal strain.
The present invention relates to a metal gasket that prevents damage to joint surfaces, achieves more effective sealing, and exhibits reasonable heat dissipation.

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 of, 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 sides of this substrate into a single plate shape, and the deck surface is formed 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 joint surface to ensure close contact and achieve an outstanding sealing effect. However, this metal gasket cannot compensate for the irregularity caused by thermal distortion of the joint surface.Moreover, the thermal strain is uneven over the entire joint surface, and in particular the areas where the cylinder holes are close to each other become hotter than other parts. The influence of thermal distortion is also large, and for this reason, there is a drawback that effective sealing cannot be achieved depending on the seal line formed by pressing beads having the same width and height.

Therefore, an object of the present invention is to increase the amount of elastic recovery of the bead in a location where the temperature is expected to be greater than the amount of elastic recovery of the bead in other locations in a metal gasket that performs a seal by forming beads on an elastic metal plate. By forming the bead in the desired shape, the above-mentioned drawbacks can be eliminated, and the joint surface with uneven thermal distortion can be reliably sealed without damaging the joint surface. The objective is to realize a metal gasket that exhibits heat dissipation.

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 formed, and two sub-plates 8 provided on both sides of this 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, for example, the sub-plates 8 may not be provided.

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 adheres to the substrate 6.

In addition, 18 is a first cylinder hole, 20 is a second cylinder hole, 22 is a cylinder hole approach portion between the first cylinder hole 18 and the second cylinder hole 20, 24 is an oil passage, and 26 is a bolt hole.

By the way, the bead 4 formed on the substrate 6 has a convex cross section, and the bead 4 has a convex cross section, and
The amount of elastic recovery of the bead 4 of the metal gasket 2 corresponding to No. 2 is large, that is, the bead width L1 and the bead height h1 are maximum, and the cylinder hole approaching portion 22
The amount of elastic recovery gradually decreases as the distance from the bead increases, and the bead width L2 and bead height h2 are the minimum in the low-heat area.

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 fastening force, and the top 4a of the bead 4 becomes a gently curved surface, and this fastening force causes surface pressure from the seal line to act on the cylinder head 10 side. At the same time, due to this fastening force, the ends 4b, 4b of the bead 4 apply surface pressure due to the seal line to the cylinder block 12 side. At this time, since the bead width L1 of the metal gasket 2 corresponding to the cylinder hole approaching portion 22 is maximum, the contact surface l1 between the top portion 4a of the bead 4 and the sub-plate 8 is also maximum. Furthermore, in this case, since the bead width L1 is sufficiently wider than the bead height h1, the amount of restoration of the bead 4 (= the same amount as the bead height h1 at most) can be increased without increasing the elastic force of the bead 4. . Therefore, in order to increase the amount of restoration of the bead 4, the elastic force of the bead 4 is strengthened.
There is no fear that it will hurt.

The metal gasket 2 is brought into close contact with the mating surface 14, which is the mating surface, due to the surface pressure exerted by the seal line, thereby preventing leakage.

By the way, during operation of the machine, the first cylinder hole 1
8 and the second cylinder hole 20 become high temperature, and the heat is released to the surroundings, and the cylinder hole approach part 22 becomes hotter than other parts due to heat radiation from both cylinder holes 18, 20, and thermal distortion also occurs. It will be larger than the part. At this time, the bead 4 of the metal gasket 2 corresponding to the cylinder hole approach portion 22 has the maximum bead width L1 and bead height h1, and has a sufficient amount of restoration, so that the influence of thermal distortion can be reliably compensated for and the bonding Leakage can be prevented by maintaining the surface 14 in a close contact state. At the same time, the cylinder head 10 and cylinder block 12 are
Thermal conduction between the parts is promoted, and rational heat dissipation from the high-temperature part to the low-temperature part is promoted.

As is clear from the above description, according to the configuration of the present invention, in a metal gasket that performs sealing by forming beads on an elastic metal plate, the amount of elastic recovery of the bead existing at a location where the temperature should be high is reduced from that at other locations. By forming the bead in a shape that should be larger than the amount of elastic recovery of the bead, the following effects can be obtained.

(1) The amount of recovery of the elastic bead can be increased in accordance with the magnitude of thermal strain, and joint surfaces with uneven thermal strain can be reliably sealed.

(2) Since the amount of elastic recovery of the bead is increased, that is, the bead width is widened, the contact surface with the sub-plate can be made wider, promoting heat dissipation in high-temperature areas, and providing a rational heat dissipation effect at the joint surface. This makes it possible to prevent local parts of the engine from becoming abnormally hot, thereby increasing the stability and durability of the engine.

(3) Since the bead width is sufficiently wide compared to the bead height, the amount of recovery of the bead can be increased, but there is no inconvenience of increasing the elastic force of the bead. There is no risk that the restoring force of the bead will damage the joint surface of the machine, which has already softened.

[Brief explanation of drawings]

The drawings show embodiments of the invention,
Figure 1 is a partially cutaway plan view of the metal gasket;
The figure is an enlarged sectional view taken along the - line in FIG. 1. In the figure, 2 is a metal gasket, 4 is a bead, 4a is the top of the bead, 4b is the end of the bead,
6 is a board, 8 is a sub-plate, 10 is a cylinder head, 1
2 is a cylinder block, 14 is a joint surface, 16 is a sealing material, 18 is a first cylinder hole, 20 is a second cylinder hole, 22 is a cylinder hole approach part, 24 is an oil passage, 26 is a bolt hole, L1, L2 are bead width,
l1 and l2 are contact surfaces, and h1 and h2 are bead heights.

Claims (1)

[Claims] 1. In a metal gasket that performs a seal by forming beads on an elastic metal plate, the shape should be such that the amount of elastic recovery of the beads in the area where the temperature should be high is greater than the amount of elastic recovery of the beads in other areas. A metal gasket characterized in that the bead is formed therein.