Method of manufacturing a steel laminate gasket

In a method of manufacturing a steel laminate gasket, a plurality of steel plates is separately prepared so that each plate is provided with a plurality of holes. Then, at least two kinds of surface pressure regulation plates are separately prepared. The thickness of the two kinds of the surface pressure regulation plates is different. The surface pressure regulation plates are mounted on one of the steel plates at predetermined portions and connected thereonto so that the surface pressure regulation plates do not move relative to the steel plate. The steel plate with the surface pressure regulation plates is assembled with at least another steel plate.

BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT 
The present invention relates to a method of manufacturing a steel laminate 
gasket with surface pressure regulation plates for use in an internal 
combustion engine. 
A steel laminate gasket is basically formed of a plurality of steel plates. 
When the steel laminate gasket is used, the steel laminate gasket is 
situated between two engine blocks and is tightened by bolts extending 
through the engine blocks. When the steel laminate gasket formed of a 
plurality of steel plates is thus used, sealing pressure applied to the 
steel laminate gasket is not even, i.e. an area adjacent the bolt receives 
sealing pressure stronger than an area away from the bolt. 
In the gasket, areas adjacent water and oil holes as well as cylinder bore 
require high sealing pressure to seal properly therearound. In order to 
provide high sealing pressure at required areas, surface pressure 
regulation plates may be attached to the gasket. 
As shown in chain lines in FIGS. 1 and 2, the surface pressure regulation 
plates are small plates having configurations similar to areas to be 
placed. When a surface pressure regulation plate 10 is situated around a 
water hole Hw, for example, the surface pressure regulation plate 10 may 
be a ring shape with an opening corresponding to the water hole Hw. 
When a steel laminate gasket with the surface pressure regulation plates is 
manufactured, required steel plates and surface pressure regulation plates 
are formed. The surface pressure regulation plates are simply situated at 
desired areas on one of the steel plates. Thereafter, the steel plate with 
the surface pressure regulation plates is assembled with other steel 
plates. The steel plates are finally connected together. 
If, for example, a surface pressure regulation plate 11 situated around a 
cylinder bore Hc is thicker than a surface pressure regulation plate 10 
situated around the water hole Hw and other surface pressure regulation 
plates, the surface pressure regulation plates 11 are situated on a plate 
13, while the surface pressure regulation plate 10 and other surface 
pressure regulation plates are situated on a plate 14. Then, the plates 
12, 13, 14 are assembled together. This is because if surface pressure 
regulation plates with different thickness are situated on one steel 
plate, after the plates are assembled together, thin surface pressure 
regulation plates may move between the steel plates. 
When surface pressure regulation plates of different kinds are installed in 
the steel laminate gasket, the conventional method of manufacturing the 
steel laminate gasket requires complicated steps. Nevertheless, the 
surface pressure regulation plates may slightly move on the steel plate. 
Further, in case the surface pressure regulation plates are small, it is 
inconvenient in the conventional method to handle these surface pressure 
regulation plates. 
Accordingly, one object of the present invention is to provide a method of 
manufacturing a steel laminate gasket with surface pressure regulation 
plates, wherein surface pressure regulation plates of any kinds can be 
immovably installed between steel plates. 
Another object of the invention is to provide a method of manufacturing a 
steel laminate gasket as stated above, wherein the steel laminate gasket 
with the surface pressure regulation plates 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 
In accordance with a method of manufacturing a steel laminate gasket of the 
present invention, at first a plurality of steel plates is prepared 
separately so that each steel plate is provided with a plurality of small 
holes. Also, at least two kinds of surface pressure regulation plates are 
separately prepared. The thickness of the surface pressure regulation 
plates of one kind is different from that of the surface pressure 
regulation plates of other kinds. The surface pressure regulation plates 
are mounted on one of the steel plates at predetermined portions and 
connected thereto so that the surface pressure regulation plates do not 
move relative to the steel plate. Finally, the steel plate with the 
surface pressure regulation plates thereon is assembled with other steel 
plates. 
The surface pressure regulation plates of one kind are provided with at 
least one opening therein respectively. The diameter of the opening is the 
same as that of the holes. Preferably, the surface pressure regulation 
plates of different kinds are installed around the respective holes. The 
surface pressure regulation plates are connected to the steel plates by 
spot welding or glue.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
Referring to FIGS. 3 and 4, a steel plate 20 with surface pressure 
regulation plates 21, 22, 23 prepared in accordance with the present 
invention is shown. The surface pressure regulation plates 21 are situated 
around cylinder bores Hc, the surface pressure regulation plates 22 are 
situated around water holes Hw, and the surface pressure regulation plates 
23 are situated around oil holes Ho. The surface pressure regulation 
plates may be situated around push rod holes Hp. 
The pressure applied around the cylinder bores Hc is higher than the 
pressure applied around the water holes Hw and the oil holes Ho. 
Therefore, the surface pressure regulation plate 21 is made thickner than 
the surface pressure regulation plates 22, 23. 
The surface pressure regulation plate 21 may be made of a metal plate, such 
as a mild steel plate or a stainless steel plate. The surface pressure 
regulation plates 22, 23 may be made of metal plates as in the pressure 
regulation plate 21. However, the plates 22, 23. may be made of thin 
plastic plates with heat resistant property. The thickness, hardness and 
kind of material of the surface pressure regulation plates are determined 
by characteristics of an engine that the gasket is installed. 
When a steel laminate gasket A as shown in FIGS. 5 and 6 is manufactured, 
materials to be used as steel plates and surface pressure regulation 
plates are selected in view of characteristics of an engine. 
Characteristics, i.e. quality, thickness and hardness, of an upper plate 
25, middle plate 26 and lower plate (steel plate) 20 are different. 
Similarly, characteristics of the surface pressure regulation plates 21, 
22, 23 are different. 
Base plates (not shown) made of desired materials are respectively pressed 
or cut to form the upper, middle and lower plates 25, 26, 20 separately, 
wherein cylinder bores Hc and other holes are formed. Also, base plates 
(not shown) are pressed or cut to form the surface pressure regulation 
plates 21, 22, 23. The surface pressure regulation plates are in doughnut 
shape and include openings corresponding to the bores or holes of an 
engine respectively. The outer configuration of the surface pressure 
regulation plates may be changed as desired. 
After the steel plates and surface pressure regulation plates are formed, 
the surface pressure regulation plates 21, 22, 23 are mounted on the lower 
plate 20 and connected thereto by spot welding. The surface pressure 
regulation plates may be attached onto the lower plate 20 by means of a 
heat resistant glue. As a result, the surface pressure regulation plates 
21, 22, 23 are immovably attached onto the lower plate 20. 
Finally, the middle and upper plates 26, 25 are situated on the lower plate 
20 and connected together. The plates 25, 26, 20 may be connected by spot 
welding. However, if a flange portion extending from a lower plate and 
situated above an upper plate is formed around a cylinder bore, since the 
flange portion holds the entire plates, it is unnecessary to connect the 
plates by spot welding. If grommets are situated around the cylinder 
bores, the plates need not be connected together by spot welding as well. 
In a steel laminate gasket B as shown in FIG. 7, surface pressure 
regulation plates are connected to an uppper plate 25' and assembled 
together with a middle plate 26' and lower a plate 20'. Since the surface 
pressure regulation plates are securely attached to the upper plate 25', 
the gasket B can be installed in an engine without any trouble. 
FIGS. 8 and 9 show a steel laminate gasket C prepared in accordance with 
the present invention. The gasket C comprises an upper plate 25", a middle 
plate 26" with surface pressure regulation plates 21" and 27, and a lower 
plate 20". When manufacturing the gasket C, the surface pressure 
regulation plates 21" are immovably placed onto the middle plate 26", and 
then the surface pressure regulation plates 27" are immovably situated on 
the surface pressure regulation plates 21". The middle plate 26" is 
finally assembled with the upper and lower plates 25", 20". 
In the gasket C, the surface pressure regulation plates 21" are installed 
to provide sealing pressure around the cylinder bores Hc. However, in case 
the rigidity of the cylinder head is low, the cylinder head may slightly 
bend along the longitudinal direction of the engine. If the cylinder head 
bends slightly, the sealing pressure between the cylinder bores decreases, 
wherein the surface pressure regulation plate 21" alone can not provide 
sufficient sealing pressure. The surface pressure regulation plate 27 is 
installed to compensate the pressure decrease. 
In the present invention, the surface pressure regulation plates can be 
securely and precisely installed on a steel plate. Further, the steel 
plates can be easily assembled together without causing slipping of the 
surface pressure regulation plates. In accordance with the present 
invention, it is possible to provide a precise steel laminate gasket with 
good quality. 
While the invention has been explained with reference to the specific 
embodiments of the invention, the explanation is illlustrative and the 
invention is limited only by the appended claims.