JPH0424587B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to a gasket sheet used as a gasket for an internal combustion engine. Conventionally, gaskets for internal combustion engines include asbestos joint sheets, asbestos beater sheets, oil sheets, cork sheets, rubber sheets, metal plates for head gaskets, iron plates with hooks, asbestos sheets reinforced with wire mesh, rubber asbestos sheets, and resin graphite sheets. etc. are used. In general, reducing the weight and improving the performance of an internal combustion engine, that is, an engine, tends to increase thermal changes in the engine itself, and increases thermal expansion and contraction of the components that make up the engine. For this reason, the gasket that is sandwiched between the parts that make up the engine and seals the internal fluid may be damaged due to thermal deformation of these parts that make up the engine, resulting in poor sealing.
The cause of such seal leakage is that the two flanges that sandwich the gasket and face each other undergo different thermal deformations due to the insulation of the gasket, causing the flanges that sandwich the gasket to move differently from each other. This is because there is a difference in movement between the front and back sides of the gasket, and the gasket is unable to cope with this difference in movement. At the same time, the movement of these opposing flanges often causes deformation of the flange at the portion where the flange has moved, resulting in insufficient surface pressure and causing fluid leakage. Therefore, an object of the present invention is to absorb the difference in movement due to thermal deformation of the flange and at the same time increase the thickness of the gasket by utilizing this difference in movement, in order to eliminate these conventional drawbacks. Therefore, it is an object of the present invention to provide a gasket sheet that prevents a decrease in the surface pressure of the gasket and further ensures fluid sealing. According to this invention, the gasket sheet is made of two metal plates each having a large number of successive pyramid-shaped convex portions.
The two metal plates are placed one on top of the other so that they fit into each other at the pyramid-shaped protrusions, leaving a gap in between.
A viscoelastic polymeric material such as natural or synthetic rubber or an intermediate material such as expanded graphite or vermiculite is sandwiched between them, and a mixture of rubber, rubber chemicals, fillers, or A surface material made by adhering and molding expanded graphite or vermiculite is provided, and the thickness changes due to misalignment of the upper and lower metal plates. Other objects, features and advantages of the invention will become apparent from the detailed description taken in conjunction with the accompanying drawings, which illustrate one preferred embodiment of the invention. As shown in FIGS. 1 to 3 of the drawings, the gasket sheet 1 of the present invention includes two metal plates 2 which are provided with a large number of convex portions 3 and stacked on top of each other to create a gap between them. It is composed of an intermediate material 4 made of a viscoelastic polymer material sandwiched between the plates 2, and a surface material 6 adhered to both outer surfaces of both laminated metal plates 2. A thin plate of iron or aluminum alloy is used for the metal plate 2, and as shown in FIGS. 2 and 3, a large number of convex portions 3 are formed by, for example, press working. In the illustrated embodiment, the convex portion 3 is pyramid-shaped, but the convex portion 3 may have other shapes, such as a truncated pyramid, a cone, a truncated cone, a hemisphere, etc. In addition, the protrusions 3 can be arranged continuously as shown in the figure, or in a discontinuous arrangement. Two metal plates 2 made of thin plates having many convex portions are placed in the same direction as shown in the figure, so that the convex portions 3 fit into each other, and between both metal plates 2. The two metal plates 2 are overlapped to form a slight gap, and an intermediate material 4 made of a viscoelastic polymeric material such as natural rubber or synthetic rubber is sandwiched in the gap between the two metal plates 2. Also,
A surface material 6 such as a mixture of rubber, rubber chemicals, filler, or expanded graphite or vermiculite is adhered to both outer surfaces of both metal plates 2 laminated in this manner, and a laminated gas is formed as shown in the figure. Butt sheet 1 is created. When the gasket sheet 1 of the present invention, which is laminated in this way, is installed between the flanges of a gasoline engine, for example, a displacement S occurs due to the movement of the flanges due to thermal deformation, as shown in FIG. When the metal plates 2, 2 are shifted from each other, the metal plates 2 move in the direction along the slopes of the convex portions 3 of the upper and lower metal plates 2, 2 that are fitted into each other, and therefore the thickness decreases. Since the gasket sheet 1 deforms in the direction of increasing deformation, it is possible to absorb the difference in thermal deformation between the flanges to which the gasket sheet 1 is attached, and also prevent a drop in surface pressure, so that a perfect seal can always be maintained without causing fluid leakage. , a suitable gasket with excellent sealing effect and durability can be obtained. One actual example of a gasket sheet constructed in accordance with the present invention constructed in this manner is shown below. Example 1 Use a 0.2mm SPCC iron plate as the metal plate, and press to form the convex part as shown. One side of this iron plate was coated with a mixture of 100 parts of rubber, 600 parts of asbestos, 3 parts of sulfur, 1 part of tetramethylthiuramide disulfide, 4 parts of dibenzothiazyl disulfide, and 100 parts of heavy calcium carbonate. Make a 0.8mm sheet. Next, after heat treatment at 150℃ for 30 minutes, room temperature vulcanization type silicone rubber is applied to the iron plate side of the sheet, and the two sheets are compressed by aligning the iron plate sides and passing between rolls. and glue. In this way, a 1.6 mm gasket sheet is obtained. With this gasket sheet,
We made an intake manifold gasket for a 1300 c.c. gasoline engine and conducted a 100 hour durability test, with no abnormalities and good results as shown in the table below.

[Table] As described above, according to the present invention, even if the gasket is affected by thermal deformation, no leakage of cooling water occurs, the gasket itself is hardly deformed, and the torque down rate is small. It can be seen that it is well suited for use in engines and is superior to conventional gaskets. Furthermore, in the gasket sheet of the present invention, the surface material attached to the outer surface of the metal plate contains a fibrous material such as glass fiber or other mineral fiber to further improve the heat insulation effect and strength. Furthermore, expanded graphite or vermiculite can be used as the intermediate material sandwiched between the metal plates.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view of one of the gasket sheets constructed according to the present invention;
The figure is a cross-sectional view of the gasket sheet of this invention.
The figure is a plan view of a metal plate used in the gasket sheet of the present invention, and FIG. 4 is a schematic cross-sectional view of the gasket sheet of the present invention when the gasket sheet is modified in use. In the figure, 1... gasket sheet, 2... metal plate, 3
... Convex portion, 4... Intermediate material, 6... Surface material.

Claims (1)

[Scope of Claims] 1. Two metal plates each having a large number of successive pyramid-shaped convex portions are placed one on top of the other so that they fit into each other at the pyramid-shaped convex portions, leaving a gap between them. A viscoelastic polymeric material such as natural or synthetic rubber or an intermediate material such as expanded graphite or vermiculite is sandwiched between the two metal plates, and rubber is applied to both outer surfaces of the laminated metal plates. A gasket sheet characterized by being formed by adhering and molding a mixture of chemicals, fillers, or a surface material such as expanded graphite or vermiculite. 2. Rubber on one side of each of the two metal plates in advance.
After applying rubber chemicals, filler mixtures or surface materials such as expanded graphite or vermiculite,
A gasket sheet according to claim 1, characterized in that two metal plates are laminated. 3. The gasket sheet according to claim 1, characterized in that a fibrous substance is contained in the surface material that is adhered and molded to the metal plate.