Seal for a joint or juncture – Seal between fixed parts or static contact against... – Contact seal between parts of internal combustion engine
Reexamination Certificate
1997-09-05
2001-11-20
Browne, Lynne H. (Department: 3629)
Seal for a joint or juncture
Seal between fixed parts or static contact against...
Contact seal between parts of internal combustion engine
C277S593000, C277S594000
Reexamination Certificate
active
06318733
ABSTRACT:
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to a metal laminate gasket, which is made thin and is provided with an elastic auxiliary sealing member.
An automobile engine has been developed to provide high power with light weight. For this purpose, a cylinder head is made of light metal or alloy, such as an aluminum alloy. Also, a cylinder block may be made of such light metal or alloy.
In case the cylinder head or cylinder block is made of light metal or alloy, the cylinder head or cylinder block is easily damaged by pressure. For example, if high pressure is formed around a cylinder bore, the cylinder bore deforms by the high pressure.
In this respect, since a metal or metal laminate gasket is strong against high temperature, the metal gasket has been gradually used for a small size engine.
In U.S. Pat. No. 4,272,085, a gasket is formed of one metal plate, wherein an area around a cylinder bore is sealed by a thick metal plate, and an elastic sealing member is formed around a fluid hole.
In U.S. Pat. Nos. 4,834,399 and 5,054,795, gaskets formed of two plates have been proposed, wherein areas around holes are sealed by one or two sealing means formed on the plates. The gasket can securely seal around the hole as intended. However, the gasket may not properly seal around a hole or cause damages to engine parts, i.e. cylinder head and/or cylinder block, if the engine parts are made of light metal.
Accordingly, one object of the present invention is to provide a metal laminate gasket for securely sealing around a hole without causing damage to engine parts made of light metal or metal alloy.
Another object of the invention is to provide a metal laminate gasket as stated above, which can securely seal around a hole by two different kinds of sealing devices.
A further object of the invention is to provide a metal laminate gasket as stated above, which has light weight and is simple in structure.
A still further object of the invention is to provide a metal laminate gasket as stated above, which can be easily and economically manufactured.
Further objects and advantages of the invention will be apparent from the following description of the invention.
SUMMARY OF THE INVENTION
A metal laminate gasket of the invention is designed to be installed in an internal combustion engine having at least one hole therein. The gasket is formed of a first metal plate, a second metal plate situated over the first plate, and an auxiliary sealing member formed on the first plate inside the second plate.
The first plate includes a base portion extending substantially throughout an entire area of the engine, a first hole corresponding to the hole of the engine, and a curved portion extending from the base portion to define the first hole. A flange extends from the curved portion in a direction away from the first hole to be situated on a part of the base portion. The flange, the curved portion and a part of the base portion constitute around the first hole a main sealing portion without substantial elasticity.
The second plate includes a second hole with an edge portion. The diameter of the second hole is larger than the diameter of the first hole. Therefore, when the first and second plates are assembled, the flange is located inside the second hole without overlapping the second plate. A space is formed between the flange and the edge portion of the second hole.
The auxiliary sealing member is formed of a non-metallic elastic material and is located in the space inside the second hole. The auxiliary sealing member is not directly exposed to the hole of the engine by the main sealing portion. Therefore, the auxiliary sealing member is not damaged by fluid inside the hole of the engine, such as combustion gas, cooling water and oil.
The thickness of the auxiliary sealing member is greater than the thickness of the flange. When the gasket is tightened, the main sealing portion is substantially non-resiliently compressed, and the auxiliary sealing member is resiliently compressed to seal around the hole.
In the gasket of the invention, the main sealing portion is formed by the flange, a part of the base portion and the curved portion, and is substantially flat. When the main sealing portion is tightened, therefore, the main sealing portion does not provide resiliency but provides equal surface pressure thereon. Thus, the areas of the cylinder head and the cylinder block around the hole are not damaged by the tightening pressure applied thereto.
When the gasket is tightened, the auxiliary sealing member is compressed to the thickness equal to that of the main sealing portion. Therefore, the auxiliary sealing member resiliently seals outside the main sealing member.
In this respect, in case the engine parts, i.e. the cylinder head and the cylinder block, are made of light metal, such as aluminum or aluminum alloy, if a strong force is applied to the engine parts, the engine parts are damaged, i.e. cylinder head or cylinder block may deform. In case the gasket has a hard portion, such as a wire ring or a bead, the engine parts may be damaged by the hard portion. Namely, a dent may be formed by the hard portion of the gasket.
In the present invention, the main sealing portion is substantially flat, and the auxiliary sealing member is formed of non-metallic elastic material. Therefore, when the gasket is tightened, the engine parts are not damaged by the gasket and is sealed properly. The auxiliary sealing member operates as secondary sealing means.
The first plate may include an inclined portion on the base portion outside the flange to surround the first hole. The flange is substantially located on the same plane as the base portion outside the inclined portion. The second plate is located on the base portion at a side opposite to the flange. In this case, two auxiliary sealing members are formed on both sides of the inclined portion.
In the present invention, the main sealing portion may have a little resiliency at the curved portion, or may be formed to constitute a solid portion on the flange. The gasket is especially useful for an engine with a relatively low tightening pressure for tightening the cylinder head to the cylinder block.
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Browne Lynne H.
Ishikawa Gasket Co., LTD
Kanesaka & Takeuchi
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