JP6344642B2 - Cylinder head gasket - Google Patents

Description

  The present invention relates to a cylinder head gasket used in an engine having a cylinder bore and a water jacket, and more particularly to a cylinder head gasket in which a partial coating layer is formed in a ring shape surrounding a combustion chamber hole.

Conventionally, a cylinder head gasket is composed of at least one gasket substrate. A combustion chamber hole is formed in the gasket substrate so as to coincide with a cylinder bore of the engine, and the combustion chamber hole is formed on one side surface of the gasket substrate. An enveloping ring-shaped partial coating layer is known (Patent Document 1).
An engine having a water jacket is also known in which a partial coating layer is formed outside the water jacket (Patent Document 2).
The reason why the partial coating layer is formed in any of the documents is that the amount of the expensive coating material used is reduced and manufactured at a low cost as compared with the case where the coating layer is formed on the entire surface.

Japanese Utility Model Publication No. 62-177963 Japanese Utility Model Publication No. 5-73361

The partial coating layer is generally formed by screen printing. However, when the coating layer is partially formed as conventionally known in the field of screen printing, the thickness of the formed coating layer is such that the contour portion is the inner portion thereof. Saddle phenomenon that is slightly thicker than that occurs.
In particular, when a partial coating layer is formed in a ring shape surrounding the combustion chamber hole as a cylinder head gasket, the contoured portion is formed at two locations, that is, an inner peripheral portion close to the combustion chamber hole and an outer peripheral portion separated from the combustion chamber hole. Since the portions are formed, the surface pressure of each portion increases.
If a portion where the surface pressure is increased is formed in an unintended portion surrounding the combustion chamber hole of the cylinder head gasket, there is a risk of adversely affecting the sealing performance.
In view of such circumstances, the present invention provides a cylinder head gasket capable of suppressing an increase in surface pressure even when there is a saddle phenomenon.

That is, the invention according to claim 1 is a cylinder head gasket for use in an engine having a cylinder bore and a water jacket, wherein the cylinder head gasket is composed of at least one gasket substrate, and the gasket substrate is attached to the cylinder bore. In the cylinder head gasket in which a combustion chamber hole is formed so as to match, and a partial coating layer is formed in a ring shape around the combustion chamber hole on one side surface of the gasket substrate,
The inner edge on the combustion chamber hole side of the partial coating layer is formed by forming the partial coating layer to the center side of the combustion chamber hole and cutting at the peripheral edge of the combustion chamber hole, And the outer edge part which is the opposite side to the combustion chamber hole of the partial coating layer is formed at a position where it overlaps with the water jacket ,
A partial coating layer is formed in a ring shape on the other surface of the gasket substrate so as to surround the combustion chamber hole, and the inner edge of the partial coating layer on the combustion chamber hole side is the center of the combustion chamber hole. The outer edge of the partial coating layer opposite to the combustion chamber hole is formed at a position where it overlaps with the water jacket. It is characterized by being.
According to a second aspect of the present invention, there is provided a cylinder head gasket for use in an engine having a cylinder bore and a water jacket, wherein the cylinder head gasket is composed of at least one gasket substrate, and the gasket substrate is attached to the cylinder bore. In the cylinder head gasket in which a combustion chamber hole is formed so as to match, and a partial coating layer is formed in a ring shape around the combustion chamber hole on one side surface of the gasket substrate,
The inner edge on the combustion chamber hole side of the partial coating layer is formed by forming the partial coating layer to the center side of the combustion chamber hole and cutting at the peripheral edge of the combustion chamber hole, And the outer edge part which is the opposite side to the combustion chamber hole of the partial coating layer is formed at a position where it overlaps with the water jacket,
A coating layer is formed on the entire surface of the other side of the gasket substrate.

According to the above configuration, the inner edge on the combustion chamber hole side of the partial coating layer forms the partial coating layer to the center side of the combustion chamber hole and cuts at the peripheral edge of the combustion chamber hole. Therefore, the contour portion on the combustion chamber hole side when the partial coating layer is formed, that is, the thick portion due to the saddle phenomenon, is cut out as the center side portion of the combustion chamber hole. Accordingly, the inner edge portion of the partial coating layer on the combustion chamber hole side is substantially the same as the thickness of the inner portion of the partial coating layer, and there is no thick portion where the surface pressure increases.
On the other hand, the outer edge portion of the partial coating layer opposite to the combustion chamber hole is a contour portion opposite to the combustion chamber hole side when the partial coating layer is formed, and this portion is a saddle phenomenon. However, since it is formed at a position where it overlaps with the water jacket, surface pressure is not generated when it is incorporated into the engine.
Therefore, it is possible to prevent an unintended surface pressure from occurring in any part of the partial coating layer.

The top view which shows the Example of this invention. The expanded sectional view which follows the II-II line of FIG.

The present invention will be described below with reference to the illustrated embodiments. In FIGS. 1 and 2, a cylinder head gasket 1 is sandwiched between a cylinder head 11 and a cylinder block 12 of an engine. The seal between them is maintained by being sandwiched between the two.
The cylinder head gasket 1 of this embodiment is composed of a single gasket substrate 2, and a plurality of combustion chamber holes 2 </ b> A are formed in accordance with the positions of a plurality of cylinder bores 12 </ b> A provided in the cylinder block 12. The inner diameters of these combustion chamber holes 2A are set substantially the same as the inner diameter of the cylinder bore 12A.
Further, a water jacket 12B (see an imaginary line in FIG. 1) surrounding each cylinder bore 12A in an endless manner is opened in the cylinder block 12, and cooling water is circulated in the water jacket 12B. ing. Further, as shown in FIG. 1, a plurality of bolt holes 3 for inserting fastening bolts into required positions of the gasket substrate 2.
And an oil hole (not shown) through which lubricating oil is circulated.

The gasket substrate 2 has a shape coinciding with the joint surface of the cylinder head 11 and the cylinder block 12, and is formed to have the same plate thickness over the entire area. The gasket substrate 2 is formed with a full bead 2B surrounding each combustion chamber hole 2A in an endless manner. In the illustrated embodiment, the full bead 2 </ b> B of the gasket substrate 2 is formed so as to bulge upward toward the cylinder head 11.
Then, a ring-shaped partial coating layer 4 surrounding each combustion chamber hole 2A is polymerized at a position where the full bead 2B is formed on one surface (upper surface) and the other surface (lower surface) of the gasket substrate 2. Is formed. The partial coating layer 4 is formed so as to be continuous with each other between the adjacent combustion chamber holes 2A.
As the material for the partial coating layer 4, a rubber material such as fluorine or nitrile, an elastomer material, or the like can be used. Thus, the partial coating layer 4 is formed on both surfaces of the gasket substrate 2 in order to improve the adhesion and sealing properties with the counterpart material.

The partial coating layer 4 is formed by, for example, screen printing, and is exaggerated in FIG. 2. In the state where the ring-shaped partial coating layer 4 is formed by coating, the partial coating layer 4 is formed on the inner peripheral side. A saddle phenomenon occurs in which the thickness of the contour portion 4a and the contour portion 4b on the outer peripheral side becomes thicker than the inner portion 4c of both.
However, in the present embodiment, the inner edge portion 4d of the partial coating layer 4 on the combustion chamber hole 2A side forms the partial coating layer 4 to the center side of the combustion chamber hole 2A, and then the combustion chamber hole 2A. Is formed by cutting at the peripheral edge of the combustion chamber hole 2A simultaneously with the punching of the combustion chamber hole 2A.

That is, when manufacturing the cylinder head gasket 1 of the present embodiment, first, the partial coating layer 4 is applied by screen printing to one side surface of the material to be the flat gasket substrate 2, and then the other. The partial coating layer 4 is also formed on the side surface by screen printing. Under the present circumstances, the outline part 4a of the inner peripheral side of each partial coating layer 4 is formed to the center side exceeding the inner peripheral part of 2 A of combustion chamber holes which should be formed.
Next, the combustion chamber hole 2A, the bolt hole 3 and the like are formed in the material to be the gasket substrate 2, and the full bead 2B is formed. As described above, the contour portion 4a on the inner peripheral side of the partial coating layer 4 is formed up to the center side of the combustion chamber hole 2A. Therefore, when the combustion chamber hole 2A is drilled, the contour of the partial coating layer 4 is formed. The portion 4a will be cut off, thereby forming an inner edge 4d having the same thickness as the inner portion 4c.
As described above, the thickness of the inner edge portion 4d on the combustion chamber hole 2A side of the partial coating layer 4 is substantially the same as the thickness of the inner portion 4c of the partial coating layer 4. There is no thick part where the pressure increases.

On the other hand, the outer edge portion of the partial coating layer 4 opposite to the combustion chamber hole is a contour portion 4b opposite to the combustion chamber hole 2A when the partial coating layer 4 is formed. The outer edge portion 4b is thicker than the inner portion 4c due to the saddle phenomenon.
However, since the outer edge 4d is formed at a position where it overlaps with the water jacket 12B, when the cylinder head gasket 1 is incorporated in the engine and interposed between the cylinder head 11 and the cylinder block 12, The outer edge 4d does not generate surface pressure.
Therefore, according to the present embodiment, since the thickness of the partial coating layer 4 is substantially the same in any portion, it is possible to prevent unintended contact pressure due to the thick portion from being generated.

In the above embodiment, the partial coating layers 4 are provided on both surfaces of the gasket substrate 2, but either one of the coating layers 4 may be formed on the entire surface of the gasket substrate 2 or may be omitted.
Further, in the above embodiment, the cylinder head gasket is constituted by one gasket substrate 2, but the cylinder head gasket may be constituted by a plurality of gasket substrates 2. In this case, a coating layer similar to that described above may be formed on each gasket substrate 2 and 2.

DESCRIPTION OF SYMBOLS 1 Cylinder head gasket 2 Gasket board | substrate 2A Combustion chamber hole 2B Full bead 4 Partial coating layer 4a Contour part 4b Outer edge part (contour part) 4c Inner part 4d Inner edge part 11 Cylinder head 12 Cylinder block 12A Cylinder bore 12B Water jacket

Claims (3)

A cylinder head gasket used in an engine having a cylinder bore and a water jacket, wherein the cylinder head gasket is composed of at least one gasket substrate, and a combustion chamber hole is formed in the gasket substrate so as to coincide with the cylinder bore. Further, in the cylinder head gasket in which a partial coating layer is formed in a ring shape surrounding the combustion chamber hole on one side surface of the gasket substrate,
The inner edge on the combustion chamber hole side of the partial coating layer is formed by forming the partial coating layer to the center side of the combustion chamber hole and cutting at the peripheral edge of the combustion chamber hole, And the outer edge part which is the opposite side to the combustion chamber hole of the partial coating layer is formed at a position where it overlaps with the water jacket ,
A partial coating layer is formed in a ring shape on the other surface of the gasket substrate so as to surround the combustion chamber hole, and the inner edge of the partial coating layer on the combustion chamber hole side is the center of the combustion chamber hole. The outer edge of the partial coating layer opposite to the combustion chamber hole is formed at a position where it overlaps with the water jacket. A cylinder head gasket. A cylinder head gasket used in an engine having a cylinder bore and a water jacket, wherein the cylinder head gasket is composed of at least one gasket substrate, and a combustion chamber hole is formed in the gasket substrate so as to coincide with the cylinder bore. Further, in the cylinder head gasket in which a partial coating layer is formed in a ring shape surrounding the combustion chamber hole on one side surface of the gasket substrate,
The inner edge on the combustion chamber hole side of the partial coating layer is formed by forming the partial coating layer to the center side of the combustion chamber hole and cutting at the peripheral edge of the combustion chamber hole, And the outer edge part which is the opposite side to the combustion chamber hole of the partial coating layer is formed at a position where it overlaps with the water jacket ,
A cylinder head gasket , wherein a coating layer is formed on the entire other surface of the gasket substrate . The cylinder head gasket is composed of a plurality of stacked gasket base plate, the cylinder according to claim 1 or claim 2, characterized in that each gasket substrate said coating layer is formed Head gasket.

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