The present invention relates to a metal laminate gasket with an identification sign, i.e. thickness identification sign of the gasket, especially for an open deck type engine.
Metal laminate gaskets have been used widely because of the strength against high pressure and high temperature, and durability thereof.
As one type of the metal laminate gaskets, a gasket is formed of a base metal plate having curved portions for defining cylinder bores and flanges extending from the curved portions, shims situated inside the flanges, and one or more metal plates laminated with the base metal plate. When the gasket is tightened between a cylinder head and a cylinder block, the flanges are strongly compressed to provide surface pressures thereat to thereby securely seal around the cylinder bores.
On the other hand, in case a cylinder head and a cylinder block are piled together without a gasket, a space between the cylinder head and the cylinder block becomes slightly different depending on the engines due to the manufacturing tolerance. In order to properly seal between the cylinder head and the cylinder block, one engine has several gaskets with different thicknesses. Before installing the gasket, the space between the cylinder head and the cylinder block is measured, and then, a gasket is selected depending on the space.
Therefore, one type of the gasket includes several gaskets with different thicknesses, and the gasket with the proper thickness must be selected and identified easily. Also, the selected gasket must be installed in the proper orientation.
In order to identify the gaskets, a gasket as disclosed in U.S. Pat. No. 5,141,237 has a plate information device. The patent works properly as intended, but the plate information device in the patent may not always formed at an ideal position. Therefore, the improvement is still required.
In view of the conventional gaskets, the present invention has been made, and an object of the invention is to provide a metal laminate gasket with a thickness identification sign, wherein the thickness of the gasket can be identified easily.
Another object of the invention is to provide a metal laminate gasket as stated above, wherein the orientation of the gasket can be also identified easily.
A further object of the invention is to provide a metal laminate gasket as stated above, wherein the gasket is suitable for an open deck type engine.
Further objects and advantages of the invention will be apparent from the following description of the invention.
A metal laminate gasket for an internal combustion engine of the invention is basically formed of a first metal plate, a shim member for adjusting a thickness of the gasket, and a second metal plate disposed under the first metal plate.
The first metal plate includes a base portion extending substantially throughout an entire area to be sealed, a plurality of cylinder bores formed in the first metal plate, a plurality of curved portions extending from the base portion to define the cylinder bores, and flanges extending from the respective curved portions to be disposed under the base portion. The shim member includes at least two shim portions, and at least one connecting portion for connecting the shim portions. Each shim portion is disposed between the base portion and one flange. Thus, the connecting portion is located between two flanges without overlapping therewith. The second metal plate has a shape such that the second metal plate does not overlap the flanges and the shim member including the connecting portion.
In the present invention, an identification sign for the gasket is formed at the connecting portion where sealing is not affected, to thereby identify the thickness of the gasket. The identification sign can be seen easily from the back side of the gasket.
In the invention, since the identification sign is formed at the connecting portion of the shim member, which is seen from the back side of the gasket without cutting any part of the gasket, the identification sign can be formed easily. Also, the identification sign does not affect the sealing ability of the gasket at the connecting portion. Thus, the gasket with the identification sign can be made easily. The gasket of the invention is especially useful for the open deck type engine.
Preferably, the second metal plate has a thickness greater than a thickness of the shim member and less than a total thickness of the shim member and the first metal plate. Thus, the gasket can provide high surface pressure at the shim portions around the cylinder bores.
The shim member is selected from a plurality of shim members with different thicknesses. Also, the shim members have the identification signs different from each other. Also, the second metal plate is selected from a plurality of second metal plates with different thicknesses. One shim member is assembled with one second metal plate so that a difference between the thickness of the second metal plate and the total thickness of the shim member and the first metal plate is constant throughout combinations of the shim members and the second metal plates while the thicknesses of the gasket are changed.
Accordingly, if a space between a cylinder head and a cylinder block is different, the gasket with the proper thickness can be selected and installed in the engine. Although the space between the cylinder head and the cylinder block is slightly different due to the manufacturing tolerance, the same quality engine can be provided.
The gasket further includes an assembly sign formed at the connecting portion of the shim member where the sealing is not affected to thereby identify a direction or orientation of the shim member relative to the first metal plate when the shim member is assembled with the first metal plate. Also, the direction or orientation of the gasket with the shim member can be identified when the gasket is install in the engine.