JPH0139872Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) This invention relates to an improvement of a cylinder head gasket that is sandwiched between the lower surface of a cylinder head and the upper surface of a cylinder block of an internal combustion engine, and maintains airtightness and liquidtightness between both surfaces.

(Background Art) A cylinder head gasket as shown in Fig. 1 is sandwiched between the lower surface of the cylinder head and the upper surface of the cylinder block of an internal combustion engine, so that high-pressure combustion gas generated within the cylinder is passed between the cylinder block and the cylinder. This prevents the cooling water or lubricating oil flowing between the head and the head from leaking to the outside.

This cylinder head gasket 1 has circular bore holes 2, 2, which match the opening shape of the top of the cylinder.
There are small circular holes 3, 3 through which bolts for fixing the cylinder head to the cylinder block are inserted, and through holes 4, 4 through which cooling water and lubricating oil pass.
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, in recent years, with the spread of turbochargers, etc., there has been a strong tendency for the thermal load on engines to become high, and metal cylinder head gaskets with good heat resistance are increasingly being used.

The metal cylinder head gasket is made by stacking three or more thin metal plates 6 to 10, such as galvanized steel plates and stainless steel plates, with bore holes etc. punched out, as shown in FIG. 2 (in the illustrated example, five plates), The grommet 5 attached to the inner peripheral edge of the bore hole 2 allows
It is constructed by bundling these plural metal thin plates 6 to 10. However, instead of being separate from each of the thin metal plates 6 to 10, the grommet 5 is often integrated with the thin metal plate 6 or 10 on the front or back side.

By the way, in such a metal cylinder head gasket, the airtightness around the bore hole 2 is maintained by the above-mentioned grommet 5, but the liquidtightness around the through hole 4 for passing cooling water and lubricating oil is maintained. , has conventionally been held using a structure as shown in FIGS. 3 and 4.

First, in the structure shown in FIG.
This is an example in which the packing 11 is fitted to the inner circumferential edge of the hole, which is smaller in diameter than the hole drilled in the thin metal plate 8.

Furthermore, in the example shown in FIG. 4, the hole drilled in one of the intermediate thin metal plates 7 and 8 has a larger diameter than the hole drilled in the other thin metal plates 6, 9, and 10. An annular bead 12 (according to the shape of the through hole, but not limited to a circular shape) is formed around the hole drilled in the remaining intermediate thin metal plate 9.
However, the structure of the area around the through hole of the conventional metal cylinder head gasket constructed as described above has the following disadvantages.

That is, in the structure shown in FIG. 3, the inner diameter of the packing 11 must be larger than the diameter of the opening of the water passage or oil passage provided in the cylinder block or cylinder head. Each thin metal plate 6, 7, 9, 1 for mounting inside
Since the hole drilled at 0 is also large, the through hole 4
If the hole 2 and other holes such as the bore hole 2 are close to each other, the width of the portion where the plurality of thin metal plates 6 to 10 are laminated becomes narrow and the strength becomes weak.

Furthermore, the structure shown in FIG. 4 also has the same disadvantages as the structure shown in FIG. 4 and other holes are close to each other, the bead 12 cannot be formed and such a structure cannot be adopted.

For this purpose, as shown in FIG. 5, holes of the same size are bored in a plurality of thin metal plates 6 to 10, and each hole is aligned to form a through hole 4, and around the upper and lower openings of the through hole 4, a silicon It has been considered to coat sealing materials 13, 13, such as rubber, in an annular shape.

However, in the structure shown in FIG. 5, in which the front and back surfaces of the metal cylinder head gasket are simply coated with sealing material 13, when this gasket is strongly clamped between the top surface of the cylinder block and the bottom surface of the cylinder head, the sealing material will evaporate. 13 becomes thinner (sag) as if crushed, and the sealing performance deteriorates.

Japanese Utility Model Publication No. 55-154852 discloses that by forming a bead surrounding a through hole in a thin metal plate sandwiched in between, a gap is formed in the bead forming part before use, and both the front and back sides are A structure is shown in which a sealing material is coated on the part that aligns with this gap.

However, during use (when the cylinder head gasket is strongly pinched between the top surface of the cylinder block and the bottom surface of the cylinder head), the gap formed by such a bead is crushed and disappears, and moreover, the gap formed by the seal material disappears. In this case, a large pressure based on the elastic restoring force of the bead is applied, and this sealing material tends to weaken.

In order to prevent the sealing material from sagging due to such causes, in the case of the device described in the above publication, grooves are formed in the thin metal plates that make up the front and back surfaces of the metal cylinder head gasket, and the grooves are filled with grooves. Coated with sealant. However, the work of forming grooves in a thin metal plate is troublesome and is not necessarily preferable due to cost issues.

(Purpose of the invention) The object of the invention is to provide a metal cylinder head gasket which eliminates the above-mentioned disadvantages, has good sealing properties, and has sufficient durability.

(Structure of the invention) The metal cylinder head gasket of the invention is
Of the three or more thin metal plates constituting the gasket, the hole bored in at least one of the intermediate thin metal plates has a larger diameter than the hole bored in the thin metal plates forming both the front and back sides. As a result, when these metal thin plates are laminated, around the through hole,
An annular gap corresponding to the thickness of the intermediate thin metal plate is formed so as to exist even during use. A sealing material is annularly coated on both the front and back surfaces of the portion around the through hole that matches the gap.

When the metal cylinder head gasket of the present invention constructed in this way is strongly clamped between the top surface of the cylinder block and the bottom surface of the cylinder head,
A sealing material coated around the through holes in the thin metal plates forming both the front and back surfaces is pressed against the top surface of the cylinder block or the bottom surface of the cylinder head.

However, in the case of the metal cylinder head gasket of the present invention, the above-mentioned sealing material is coated on a part of the thin metal plate that forms the front and back surfaces of the metal cylinder head gasket, and is coated on the part that matches the gap. However, it becomes possible to elastically deform by the gap equivalent to the thickness of the intermediate thin metal plate in which a large diameter hole is drilled to form the above gap, and the sealing material coated on the front and back surfaces of the gasket This prevents the sealing material from sagging due to excessive pressing force.

(Embodiments of the Invention) Next, the present invention will be explained in more detail by explaining the illustrated embodiments.

6-7 show a first embodiment of the invention. In a cylinder head gasket 1 made up of five laminated metal sheets 6 to 10, small-diameter circular holes 14, 14 is
Large diameter circular holes 15, 15 are provided in the intermediate thin metal plates 7 to 9.
are perforated, and each thin metal plate has 6 to 10 holes.
In the stacked state, an annular gap 16 is provided between the thin metal plate 6 on the front side and the thin metal plate 10 on the back side. Circular hole 1 bored in both the metal thin plates 6 and 10
4 and 14 are aligned with the gap 16,
Further, the front and back surfaces of the cylinder head gasket 1 are coated with a sealing material 13 in an annular shape.

The metal cylinder head gasket of the present invention constructed in this manner is similar to the case of conventional gaskets, as shown in FIG.
The sealing material 1 of the front and back metal thin plates 6 and 10 is sandwiched between the upper surface of the cylinder head 7 and the lower surface of the cylinder head 18.
The portion coated with 3 is elastically deformable in the direction in which the distance between the plates 6 and 10 becomes narrower due to the presence of the gap 16, and as the upper surface of the cylinder block and the lower surface of the cylinder head are brought closer, the portion coated with the above-mentioned is deformed as shown in FIG. 7, which prevents the coated sealant from sagging.

When the metal cylinder head gasket is strongly clamped between the upper surface of the cylinder block 17 and the lower surface of the cylinder head 18, the sealing material 13
The thin metal plates 6 and 10 coated with the above elastically deform as shown in FIG. In this case,
Since the elastically deformable portion coated with the sealing material 13 is formed in a closed annular shape over the entire circumference of the through hole 4, a sufficiently large elastic restoring force exists, and the sealing material 13 is coated with the upper surface of the cylinder block 17. Alternatively, it is pressed against the lower surface of the cylinder head 18 with sufficient force to maintain a liquid tightness around the through hole 4.

Next, in the second embodiment shown in FIG. 8, one thin metal plate 20 is sandwiched between the thin metal plate 6 on the front side and the thin metal plate 10 on the back side, making a total of three thin metal plates. This constitutes a metal cylinder head gasket. A metal ring 21 having the same thickness or less as the intermediate thin metal plate 20 is fitted and fixed to the inner circumference of the annular gap 16 formed between the thin metal plate 6 on the front side and the thin metal plate 10 on the back side. ing. A sealing material 13 is coated on both the front and back thin metal plates 6, 10 at elastically deformable portions that are outside the metal ring 21 and the intermediate thin metal plate 20. In this embodiment, the portions of the thin metal plates 6 and 10 coated with the sealing material 13 are not as easily deformed elastically as in the first embodiment shown in FIGS.
If a relatively hard material is used as No. 3, it is fully practical.

That is, in the case of this embodiment, the inner edges of the thin metal plates 6 and 10 coated with the sealant 13 are not deformed, but are located between the inner edge of the thin metal plate 20 and the metal ring 21, and the sealant 13 is coated with the sealant 13. The coated portion is elastically recessed to prevent excessive pressing force from being applied to the sealing material 13, thereby preventing the sealing material 13 from becoming sag.

Furthermore, in the third embodiment shown in FIG.
A short cylindrical portion having a height equal to the thickness of the intermediate thin metal plate 20 is located at the peripheral edge of the circular hole 14 bored in one of the two metal thin plates 6 and 10 forming the front and back sides. 22, and this short cylindrical part 2
2 is brought into contact with the other thin metal plate 6.
The metal cylinder head gasket having the structure of the third embodiment shown in FIG. 9 can be used under the same conditions as the metal cylinder head gasket having the structure of the second embodiment shown in FIG.

That is, in the case of this embodiment as well, the inner edges of the thin metal plates 6 and 10 coated with the sealant 13 are not deformed, but are located between the inner edge of the thin metal plate 20 and the short cylindrical portion 22, and the sealant 13 is coated with the sealant. The portion coated with 13 is elastically recessed to prevent excessive pressing force from being applied to the sealing material 13, thereby preventing the sealing material 13 from sagging.

In addition, in the above-mentioned embodiment, when there are multiple intermediate thin metal plates, an example was shown in which the holes drilled in all the intermediate thin metal plates were made to have a large diameter, but when there are two or more intermediate thin metal plates, In this case, if the hole drilled in at least one thin metal plate has a large diameter, the sealing material coated portions of the front and back metal sheets can be elastically deformed, and the sealing material can be prevented from sagging.

(Effects of the invention) The metal cylinder head gasket of the invention is configured and used as described above, but since the sealing material is coated around the through hole, the through hole that is close to other holes such as the bore hole is It is possible to keep the surrounding area liquid-tight, and it also prevents excessive pressure from being applied to the area coated with sealing material, thereby preventing the sealing material from sagging, minimizing deterioration of liquid-tightness. can be kept to a minimum.

[Brief explanation of drawings]

Fig. 1 is a plan view showing an example of a cylinder head gasket to which the present invention is applied, Fig. 2 is an enlarged sectional view taken along line A-A of Fig. 1 showing an example of a metal cylinder head gasket, and Fig. 3 Figures 5 to 5 are enlarged sectional views taken along line B-B in Figure 1 showing three examples of conventional metal cylinder head gaskets, and Figure 6 is an enlarged sectional view of Figure 1 showing the first embodiment of the metal cylinder head gasket of the present invention. An enlarged BB sectional view, FIG. 7 is a sectional view showing the state in which this metal cylinder head gasket is sandwiched between the cylinder block and the cylinder head, and FIG.
9 are sectional views similar to FIG. 6 showing second and third embodiments of the present invention. 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: packing, 12: bead, 13: sealing material, 14, 1
5: Circular hole, 16: Gap, 17: Cylinder block, 18: Cylinder head, 20: Thin metal plate, 2
1: Metal ring, 22: Short cylindrical part.

Claims (1)

[Scope of utility model registration request] A metal cylinder head gasket has three or more thin metal plates with a plurality of holes including bore holes and through holes through which liquid passes, and the upper and lower surfaces around the through holes are coated with a sealing material in an annular shape. Of the holes drilled in three or more thin metal plates to form the above-mentioned through holes, the size of the hole drilled in at least one of the thin metal plates forming both the front and back surfaces is determined by adjusting the size of the hole in the middle thin metal plate. By making the size of the hole smaller than the size of the hole to be drilled, a gap that exists even during use is created between the front and back metal thin plates around the hole, in the area that matches the area coated with the sealing material. A metal cylinder head gasket featuring: