Seal for a joint or juncture – Seal between fixed parts or static contact against... – Contact seal between parts of internal combustion engine
Reexamination Certificate
2001-06-29
2003-04-22
Knight, Anthony (Department: 3676)
Seal for a joint or juncture
Seal between fixed parts or static contact against...
Contact seal between parts of internal combustion engine
C277S590000, C277S591000, C277S594000
Reexamination Certificate
active
06550782
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a metallic gasket material that provides a base for making a cylinder head gasket adapted for use on the cylinder head of an internal-combustion engine or like gasoline engine mounted on an automotive vehicle, and more particularly to such a cylinder head gasket that comprises a thin spring steel sheet having beads formed thereon.
2. Description of the Prior Art
Typically, a conventional metal cylinder head gasket includes an elastic metal sheet having beads formed like projections or steps in cross section, wherein the said beads may serve to seal the joint surfaces between the cylinder head and cylinder block of an internal-combustion engine, for example. This gasket provides an effective means for sealing the joint, and has been employed for the practical use in the fields, such as the automobile engines. In general, the cylinder head gasket has a coating of an elastic sealing material containing a rubber material as a base component applied on the front side or rear side, or both, of the cylinder head gasket, as disclosed in Japanese patent application now laid open to public inspection under Japanese Patent Publication No. 63-A-96359. The coating of an elastic sealing material is provided to increase the sealing capability of the gasket.
For recent years, there have been demands for small-size, light-weight engines as well as for engines that produce less exhaust gases. For the small-size, light-weight engines, the engines might lose the mechanical rigidity by themselves, whereas for the less exhaust gas engines, the engines might produce higher temperatures. Thus, demands arise for cylinder head gaskets that address the above problems and solve them effectively.
For the engines that has the rigidity problem as firstly mentioned, using the conventional cylinder head gasket to close the cylinder block of the engine tightly would tend to cause the deformation on the cylinder block by the tightening action. This would make it difficult to apply the uniform tightening force to the cylinder head gasket to tighten the cylinder block.
For the engines that has the high temperature problem as secondly mentioned, there is a remarkable difference in the temperature between the exhaust port side and suction port side of the cylinder block, which would cause the thermal deformation to develop on the joint between the cylinder head and cylinder block. When the conventional cylinder head gasket is used on such engines, the part of the gasket that seals the joint between the cylinder head and cylinder block would develop a partial difference in the surface pressure upon the joint. If any excessive temperature differential should occur, the coating of the elastic sealing material including a rubber base on the cylinder head gasket would be degraded by the thermal effect, which would subject the coating of the sealing material to the stress relief. Thus, the restorability of the gasket required to seal the joint would be reduced considerably.
One possible solution to the above problem is to use the elastic sealing material that contains any rubber material that has the good thermal resistance, and to employ such elastic sealing material for the gasket. But, this would have the unfavorable effect of increasing the manufacturing cost and therefore the product cost, which is not desirable for the practical and commercial reasons.
SUMMARY OF THE INVENTION
The present invention addresses the problems of the conventional cylinder head gasket as described above, and provides a cylinder head gasket that solves both the rigidity problem of the engine itself and the high temperature problem of the engine in an effective manner.
Specifically, it is an object of the present invention to provide a cylinder head gasket when it is used to close the cylinder block of the engine, the uniform tightening force can be applied to the cylinder block and cylinder head by the said cylinder head gasket, while the said cylinder head gasket can provide the constant surface pressure even when it is exposed to the excessive temperature differential caused by the rising temperature within the engine, and can maintain the restorability and conformability of the gasket that are required to seal the cylinder head for a long time under such situations.
More specifically, the present invention proposes to provide a cylinder head gasket for an internal-combustion engine that comprises an elastic metal sheet having more than one combustion chamber openings or orifice and more than one passage hole, wherein the elastic metal sheet has a bead formed in the area surrounding the combustion chamber opening and a bead formed in the area surrounding the passage hole, respectively, and has a coating of a sealing material on the front side or rear side, or both, of the elastic metal sheet.
In order to overcome the problems described above, the cylinder head gasket according to the present invention has the following features that characterize the present invention, which will be described below.
One of the features is that the sealing material that may be used to form a coating layer on the front side or rear side, or both, of the bead formed in the area surrounding the combustion chamber openings includes any thermally resistant sealing material. Another feature is that the sealing material that may be used to form a coating layer on the bead formed in the area surrounding the passage holes includes any water/oil resistant sealing material.
In other words, the area surrounding the combustion chamber opening that is exposed to the high temperatures has a coating of the sealing material that can meet the requirements for the high temperature resistance, and the area surrounding the passage hole that is required to provide the high sealing capability against the water and/or oil have a coating of the sealing material that can meet the requirements for the water/oil resistance.
In the cylinder head gasket according to the present invention, the thermally resistant sealing material may be composed of a principal component of fluorine rubber, and any one or ones of the components consisting of expanded graphite, organic fiber, inorganic fiber, organic filler, inorganic filler, and synthetic resins.
The fluorine rubber is highly resistant to the heat, but is expensive. Thus, using lots of fluorine rubber would increase the manufacturing cost, which increases the product cost accordingly. In the cylinder head gasket according to the present invention, however, it may be appreciated from the foregoing description that the coating of the thermally resistant sealing material may only be applied to the bead formed in the area surrounding the combustion chamber openings that are exposed to the high temperatures in the combustion chamber, and that the said thermally resistant sealing material may be composed of the principal component of the fluorine rubber, and any one or ones of the components mentioned above. This can tend to maintain the highly thermal resistance of the sealing material while reducing the manufacturing cost.
In the cylinder head gasket of the present invention, the sealing material that provides the water and/or oil resistance may be composed of a rubber material, and any inorganic fiber or organic fiber.
In the cylinder head gasket of the present invention, the bead formed in the area surrounding the combustion chamber opening may preferably be formed like a full bead having the convex shape in cross section that can provide the spring action, since the area surrounding the combustion chamber opening is always exposed to the high temperatures and high pressures that are developed within the combustion chamber.
Similarly, the bead formed in the area surrounding the passage hole may preferably be formed like a half bead having the stepped shape in cross section that can provide the surface pressure adjusting function.
In the cylinder head gasket of the present invention, the bead formed in the area surrounding the combustion chamber opening
Matsumoto Kenji
Nanba Takashi
Okazaki Yoshimichi
Tanaka Yoshitaka
Knight Anthony
Peavey Enoch
Uchiyama Manufacturing Corp.
LandOfFree
Cylinder head gasket does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cylinder head gasket, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cylinder head gasket will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3082366