JPH0243939B2 - METARUGASUKETSUTONOSEIZOHOHO - Google Patents

Description

Detailed Description of the Invention a.Object of the Invention (Field of Industrial Application) A method for manufacturing a metal gasket according to the present invention is to provide a metal gasket which is sandwiched between, for example, the lower surface of a cylinder head of an internal combustion engine and the upper surface of a cylinder block. To provide a metal cylinder head gasket that can be used for manufacturing a cylinder head gasket that maintains airtightness and liquidtightness for a long period of time.

(Prior art) For example, in an internal combustion engine, a cylinder head gasket is sandwiched between the lower surface of the cylinder head and the upper surface of the cylinder block, and the high-pressure combustion gas generated within the cylinder or between the cylinder block and the cylinder head is This prevents the circulating cooling water and lubricating oil from leaking to the outside.

FIG. 2 shows an example of such a cylinder head gasket 1. This cylinder head gasket 1 includes circular bore holes 2, 2 that match the opening shape of the top of the cylinder, small circular holes 3, 3 through which bolts for fixing the cylinder head to the cylinder block are inserted, and cooling water for lubrication. Through hole 4 for passing oil,
4 is drilled. Reference numeral 5 designates a grommet made of a thin metal plate attached to the inner peripheral edge of each bore hole 2,2.

Conventionally, such a cylinder head gasket 1 is manufactured by applying a compound containing asbestos or carbon as a main component to the front and back surfaces of a core material such as an iron plate with a hook or a wire mesh, or by applying a compound containing asbestos or carbon as a main component, or by applying a compound containing these materials as a main component. It was made by pasting. However, due to the spread of turbochargers in recent years, there has been a strong tendency for the heat load on engines to increase, and metal cylinder head gaskets with good heat resistance are increasingly being used.
The metal cylinder head gasket is made of thin metal plates 6 to 10, such as galvanized steel plates or stainless steel plates, with bored holes etc. punched out, as shown in Fig. 3.
A plurality of thin metal plates 6 to 10 are stacked one on top of the other (five in the example shown in FIG. 3) and are bundled by a grommet 5 attached to the inner peripheral edge of the bore hole 2. However, grommet 5 has each thin metal plate 6 to 10.
Instead of separating it from the metal thin plate 6 on the front or back side.
Or, it is often combined with 10.

Further, as shown in FIG. 3, a protrusion 11 surrounding the bore hole 2 is formed on one of the intermediate thin metal plates 7 to 9 to connect the metal cylinder head gasket to the cylinder. When the block is strongly clamped between the upper surface of the block and the lower surface of the cylinder head, the contact pressure around the bore hole 2 is increased, so that the airtightness of this region is maintained well.

In addition, for uses other than cylinder head gaskets, for example, as a gasket to be clamped between flanges for connecting exhaust pipes, a metal gasket 12 made of only one thin metal plate 13, as shown in FIG. 4, can be used. Even in the case of such a single-plate metal gasket 12, a protrusion 11 is formed around the entire circumference of the hole 14 through which the fluid passes. .

(Problems to be Solved by the Invention) However, in the case of metal gaskets constructed and used as described above, conventional problems arise as described below.

That is, the higher the height of the protrusion 11 formed around the holes 2 and 14 over the entire circumference, the greater the surface pressure can be obtained when the protrusion 11 is sandwiched between the surfaces to be sealed. Although the airtightness and watertightness are improved, for example, as shown by the chain line in FIG. When clamped and pressed between surfaces 15 and 16, this protrusion 11 cannot be completely crushed with the limited pressing force obtained by tightening bolts, etc., and this protrusion 11 is As shown by the solid line, it remains inflated.

The elasticity of the protrusion 11 is maintained as it is, and the protrusion 11 is on both sides 15 and 16 during the period of use of the metal gasket 12.
If the metal gasket 12 is stretched sufficiently strongly between the metal gaskets, no particular problem will occur.However, during use, the metal gasket 12 is exposed to the heat generated by the engine and is further subjected to engine vibrations, so the protrusions 11 may become weak. Otherwise, the tension of the protrusion 11 becomes weaker, and the sealing performance between the surfaces 15 and 16 deteriorates.

The method for manufacturing a metal gasket of the present invention provides a metal gasket that does not have the above-mentioned disadvantages.

b. Purpose of the invention (means for solving the problem) In the method for manufacturing a metal gasket of the present invention, the gasket is made of a thin metal plate and has a hole for passing a fluid, and a gasket is provided around the entire circumference of the hole. When manufacturing a metal gasket having a continuous protrusion, a thin metal plate is first press-formed so that the height of the protrusion is greater than a desired value.

A thin metal plate with such high protrusions was used as a metal gasket (3rd stage) before it was used as a metal gasket.
As shown in the figure, when used by laminating with other thin metal plates that do not form protrusions, it may be used before or after lamination. ), the ridges are compressed between mutually opposing molds to make the height of the ridges a desired value.

(Function) As mentioned above, a thin metal plate having a protrusion that is once formed higher than a desired height and then compressed to a desired height can be used as it is or with other thin metal plates, as in the conventional case. They are used in combination as a metal gasket, but the protrusions that are formed high and then compressed are harder than the protrusions that were originally formed at that height, and are less likely to collapse when compressed. , sufficient tensile force can be obtained over a long period of time.

(Example) When implementing the metal gasket manufacturing method of the present invention and forming protrusions around a plurality of holes, the amount of compression of each protrusion before using the metal gasket is not necessarily the same. They don't have to be equal.

For example, as shown in Figure 2, in the case of a metal cylinder head gasket that has multiple (four in Figure 2) bore holes 2, 2, multiple bolts are required to fix the cylinder head to the cylinder block. When tightened, the force pressing the metal cylinder head gasket is large at both ends as shown in Figure 2.
It gets smaller in the center.

For this reason, the amount of compression of the protrusions formed around the bore holes 2, 2 at the center before use is reduced, and the amount of compression before use of the protrusions formed around the bore holes 2, 2 at both ends is reduced. If the amount of compression is increased, the relationship between the elongation tension of the protrusions formed around each bore hole 2, 2 and the pressing force due to tightening of the bolt becomes an optimal condition around each bore hole.

In this case, the difference in compression amount is
By changing the amount of compression of the protrusions formed at the same height,
Even if the height of each ridge after compression is different, it is possible to compress ridges formed with different heights by different amounts so that the height of each ridge is the same after compression. You can also make it so that

Furthermore, changing the amount by which the protrusion 11 is compressed before use may be performed for each protrusion 11. For example, in the case of the bore hole 2 located at the right end in FIG. 2, the pressing force when tightening the bolt is large on the right side near the gasket end, and small on the left side near the center. For this reason, as shown in FIG.
1, the relationship between the pressing force and the tensile force is optimal. In this case as well, in order to change the amount of compression, the ridges that have been formed with different heights depending on the location are compressed so that the height after compression is the same over the entire length of the ridges. It's okay.

c. Effects of the invention The method for producing a metal gasket of the present invention is configured as described above, and the protrusions of the produced metal gasket are difficult to flatten and can exhibit good sealing performance over a long period of time. .

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an aspect of the method for manufacturing a metal gasket of the present invention, FIG. 2 is a plan view of a cylinder head gasket, FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2, and FIG. FIG. 5 is a cross-sectional view of a single-plate metal gasket, showing a state in which a metal gasket with tall protrusions is pressed. 1... Cylinder head gasket, 2... Bore hole,
3... Small circular hole, 4... Through hole, 5... Grommet, 6,
7, 8, 9, 10...Thin metal plate, 11...Protrusion, 12
...metal gasket, 13...metal thin plate, 14...
Hole, 15, 16...plane.

Claims (1)

[Claims] 1. A method for manufacturing a metal gasket made of a thin metal plate and having a hole for passing fluid, and a protrusion formed around the entire circumference of the hole, the height of the protrusion being a desired value. After press-forming a thin metal sheet to be larger than the above, and before using this metal gasket, the thin metal sheet with large protrusions is compressed between mutually opposing molds to form the above-mentioned protrusions. A method for manufacturing a metal gasket that makes the height of the strips a desired value.