JPH0232942Y2 - - Google Patents

Description

[Detailed description of the invention] a. Purpose of the invention (industrial application field) The gasket sheet according to this invention is used to store cylinder head gas for maintaining airtightness between the upper surface of the cylinder block and the lower surface of the cylinder head of an internal combustion engine. Can be used when making butts.

(Prior Art) A cylinder head gasket for maintaining airtightness and liquidtightness between the upper surface of a cylinder block and the lower surface of a cylinder head of an engine is constructed, for example, as shown in FIG. 2. This cylinder head gasket 1 has circular bore holes 2, 2 that match the opening shape of the top of the cylinder, small circular holes 3, 3 through which bolts for fixing the cylinder head to the cylinder block are inserted, and holes for cooling water and lubricant. Through hole 4 for passing oil,
4 is drilled. 5 is a grommet made of a thin metal plate attached to the inner peripheral edge of each bore hole 2, 2;
This grommet 5 is attached to the peripheral edge of each bore hole 2, 2, as shown in FIG. 3, so that the thickness of the cylinder head gasket 1 at this peripheral edge is slightly larger than the other parts. When this cylinder head gasket 1 is strongly pressed between the upper surface of the cylinder block and the lower surface of the cylinder head, the pressing force on the peripheral edge of each bore hole 2, 2 provided with such a grommet 5 is made particularly large. It is something to do. That is, by particularly increasing the pressing force on the peripheral edges of the bore holes 2, 2, high-pressure combustion gas generated within the cylinder is effectively prevented from leaking to the outside.

A gasket sheet 8 for manufacturing such a cylinder head gasket 1 has a fourth gasket on both the front and back surfaces.
An iron plate 7 on which short cylindrical hooks 6, 6 are formed as shown in the figure is used as a core material, and a compound containing asbestos or graphite as a main component is rubbed into both the front and back sides of this iron plate 7, or a sheet is preliminarily coated. They were made by forming shapes into shapes and pasting them together. After the compound is rubbed into the sheet material or after the sheet materials are bonded together, the properties of the front and back surfaces of the sheet material are exactly the same. That is, the edge of the hook 6 formed on the iron plate 7 serving as the core material was either not exposed on either the front or back of the sheet 8, or was exposed on both the front or back, as shown in FIG. .

(Problems to be Solved by the Invention) However, in the case of the conventional gasket sheet as described above, when it is formed into a gasket and used, it causes the following disadvantages.

That is, in the case of internal combustion engines, cylinder heads are increasingly made of aluminum alloy in order to reduce the weight of the engine and take measures against exhaust gas treatment. Even when the cylinder head is made of aluminum alloy in this way, the cylinder block is conventionally made of cast iron for reasons of strength or material costs. The cylinder block and cylinder head reach high temperatures during operation of an internal combustion engine and undergo thermal expansion, but the amount of thermal expansion in this case is considerably greater (approximately twice) for the cylinder head made of aluminum alloy than for the cylinder block made of cast iron. growing. Therefore, when the seat 8 is used sandwiched between the lower surface of the cylinder head 9 made of aluminum alloy and the upper surface of the cylinder block 10 made of cast iron as shown in FIG. Different magnitudes of tensile stress are applied to the front and back surfaces of the sheet 8, and uneven and unreasonable stress is applied to the sheet 8. As a result, the seat 8 may be torn as the internal combustion engine is repeatedly operated and stopped. A compound that is rubbed into the front and back surfaces of the iron plate 7 with hooks, which serves as the core material, and a sheet-like material that is pasted on the front and back surfaces are made of a material with a low coefficient of friction such as graphite, and the hooks 6 are placed on either the front or back surface of the sheet 8. If the lower surface of the cylinder head 9 and the upper surface of the cylinder block 10 are prevented from being exposed, the front and back surfaces of the sheet 8 will easily rub against each other, and no undue stress will be applied to the sheet 8. However, if the sheet 8 is As a result, as the internal combustion engine is repeatedly started and stopped, the seat 8 becomes displaced from its predetermined clamping position between the lower surface of the cylinder head and the upper surface of the cylinder block. The distance by which the seat 8 shifts in this way is only the distance that the bolts inserted through the small circular holes 3, 3 (Fig. 2) can move within these small circular holes 3, 3.
Although it is not that large, it is preferable because the edges of the through holes 4, 4 partially block the openings of the water holes and oil holes provided in the cylinder block and cylinder head, narrowing the water and oil flow paths. do not have.

The object of the present invention is to provide a gasket sheet that is free from such inconveniences.

b. Structure of the invention (Means for solving the problem) The gasket sheet of the present invention, like conventional gasket sheets, uses an iron plate with many hooks formed on the front and back sides as a core material, and the front and back surfaces of this iron plate are It is made by rubbing a compound onto the back surface or by pasting together sheets formed in advance, but unlike conventional gasket sheets, the front and back surfaces have different properties.

To explain in more detail with reference to the drawings, the gasket sheet of the present invention uses as a core material an iron plate 7 on which a large number of hooks 6, 6 are formed on both the front and back sides, as shown in FIG. Both the front and back surfaces of the gasket are covered with gasket material 11. The thickness of covering the gasket material 11 is made different on both the front and back surfaces of the iron plate 7, so that on one surface, the edges of the hooks 6, 6 are exposed from the gasket material 11, and on the other surface, the edges of the hooks 6, 6 are exposed from the gasket material 11. 6, 6 are completely buried inside the gasket material 11 so that the edges of each hook 6, 6 are not exposed from the gasket material 11.

Further, the gasket material 11 covering at least the surface of the hooks 6, 6 on which the end edges are not exposed (the bottom surface in FIG. 1) is made of a slippery material with a low coefficient of friction.
As a slippery material that can be used as the gasket material 11, a material containing graphite as a main component, such as expanded graphite, can be considered. The gasket material 11 covering the surface of the hooks 6, 6 on which the edges are not exposed (the top surface in FIG. 1) may be made of a material with a low coefficient of friction similar to that described above, but it may be made of a material containing asbestos or the like as its main component. It is also possible to use a material with a high coefficient of friction.

(Function) The gasket sheet of the present invention, constructed as described above, is made by punching out necessary holes and attaching grommets etc. to form a gasket, as in the case of conventional gasket sheets, and the gasket is made airtight. , the surface where the hook 6 is exposed (bottom surface in Figure 1) is sandwiched between surfaces that should maintain liquid tightness, but in this case, the surface where the hook 6 is exposed (bottom surface in Figure 1) is placed on a surface with a small amount of thermal expansion and little movement during use, such as the top surface of the cylinder block. The surface on which the hook 6 is not exposed (the top surface in FIG. 1) is made to face a surface that has a large amount of thermal expansion and is moved a large amount during use, such as the bottom surface of the cylinder head.

If the gasket is held in this state and the surfaces that should be kept airtight and liquid tight, such as the bottom surface of the cylinder head and the top surface of the cylinder block, are strongly pressed together, the exposed surface of one side of the sheet that makes up the gasket will be removed. The edges of the hooks 6, 6 strongly abut against the top surface of the cylinder block or other surfaces that move little during use, and these edges bite into the top surface of the cylinder block, so that the gasket does not touch the top surface. It prevents it from moving in the plane direction.
When the gasket material 11 constituting one surface of the sheet (the surface where the end edges of the hooks 6, 6 are exposed) is made of a material with a high coefficient of friction mainly made of asbestos, the movement prevention effect of the gasket is It becomes even more certain. Furthermore, the hooks 6, 6 are not exposed on the other surface of the sheet that comes into contact with a surface that moves a large amount during use, such as the lower surface of the cylinder head, and the gasket material 11 constituting this surface is not exposed as described above. Made of slippery material with a low coefficient of friction,
Even if the lower surface of the cylinder head or the like moves significantly relative to the other surface of the seat during use, both surfaces slide relatively smoothly and no undue stress is applied to the seat.

c. Effects of the invention Since the gasket sheet of the present invention is constructed and functions as described above, when used as a cylinder head gasket for an internal combustion engine having a cylinder head made of aluminum alloy, it can be used to control the operation and stopping of an internal combustion engine. Even if this is repeated, no unreasonable force is applied to the sheet constituting the cylinder head gasket, and the mounting position of the gasket does not shift with use. Therefore, the airtightness and liquidtightness of the part where the gasket is held can be maintained well for a long period of time, and the flow of fluid flowing through the holes provided in the gasket is not adversely affected.

[Brief explanation of the drawing]

Figure 1 is a partial sectional view showing the gasket sheet of the present invention, and Figure 2 is a cylinder head gasket made using the gasket sheet of the present invention.
A plan view showing an example, FIG. 3 is an enlarged AA sectional view of FIG. 2 showing the case of a conventional sheet, FIG. 4 is an enlarged perspective view showing a hook formed on a steel plate serving as a core material, and FIG. 5 1 is a partial cross-sectional view showing the state in which a cylinder head gasket using a conventional gasket sheet is used. 1... Cylinder head gasket, 2... Bore hole, 3... Small circular hole, 4... Through hole, 5... Grommet, 6... Hook, 7... Steel plate, 8... Sheet,
9...Cylinder head, 10...Cylinder block, 11...Gasket material.

Claims (1)

[Scope of utility model registration request] In a gasket sheet consisting of an iron plate serving as a core material with a large number of hooks formed on the front and back surfaces, and a gasket material covering the front and back surfaces of this iron plate, the edges of the hooks formed on the iron plate are attached to the gasket sheet. 1. A gasket sheet, characterized in that the gasket material that is exposed only on one of the front and back surfaces and that constitutes the other surface on which at least the edge of the hook is not exposed is made of a material with a low coefficient of friction.