JPH0744851Y2 - Metal gasket for cylinder head - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal gasket for a cylinder head of a multi-cylinder engine.

[0002]

2. Description of the Related Art A gasket for a cylinder head mounted between the joining surfaces of a cylinder block and a cylinder head of an engine is made of a metal plate and is made of elastic metal plates on both sides of an intermediate plate having a fold-back on the edge of a cylinder bore. A metal gasket is used in which an outer substrate is laminated with a bead surrounding a cylinder bore. In this gasket, a bolt that joins the cylinder head to the cylinder block is tightened, and when the gasket is tightened between the joining surfaces, a bead that surrounds the cylinder bore of the outer substrate forms a seal line with high surface pressure on the joining surface. The high pressure gas in the combustion chamber is sealed. In addition, the fold-back provided on the cylinder bore edge of the intermediate plate serves to compensate for the clearance around the cylinder bore caused by the bending of the cylinder head due to the bolt fastening force and prevent the leakage of combustion gas, and at the same time, to prevent the explosion gas pressure in the combustion chamber. The alternating repetitive load applied to the bead due to the lifting of the cylinder head due to is prevented to prevent the bead from sagging or being damaged, thereby improving the durability of the gasket.

[0003]

In the metal gasket described above, the bead surrounding the cylinder bore of the outer substrate and the folding back of the cylinder bore edge of the intermediate plate are uniformly formed around the entire circumference of the cylinder bore. Where
In the above-mentioned metal gasket mounted between the cylinder block and the cylinder head of the multi-cylinder engine,
The combustion heat from the cylinders is received from both sides between the adjacent cylinder bores, that is, between the bores, so that it is more affected by heat than the other portions around the cylinder bores and becomes high temperature. Therefore, in each bead surrounding the cylinder bore of the outer substrate, the bead portion located between the bores, that is, the bead in the vicinity of the adjacent cylinder bore, is most likely to be worn or damaged. Also, since the combustion heat from the cylinder and the high-temperature exhaust gas are also double affected by the heat of combustion from the cylinder in the vicinity of the exhaust port around the cylinder bore, the bead in this part is the same as the bead between the bores and other parts. More likely to cause fatigue and damage than the beads.

In view of the above points, the present invention provides a bead at a position near an adjacent cylinder bore and an exhaust port which are most strongly affected by heat around the cylinder bore and are liable to be sacrificed or damaged. By reducing the load applied to the bead, the bead is prevented from sagging or damaged, and the durability of the cylinder head gasket is improved.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a folding width of a folding edge of a cylinder bore provided on an intermediate plate at a position close to an adjacent cylinder bore or at a position close to an adjacent cylinder bore. Wider at the location near the exhaust port than at other locations.

[0006]

The fold-back of the cylinder bore edge of the intermediate plate compensates for the gap around the cylinder bore due to the bending of the cylinder head caused by the bolt tightening force due to the wall-thickness increasing effect, but on the other hand, at this fold-back portion having the wall-thickness increasing effect. Consumes a large amount of load applied to the gasket based on the bolt fastening force. In the metal gasket for a cylinder head according to the present invention, the folding width of the fold of the cylinder bore edge of the intermediate plate is close to the adjacent cylinder bores, or is close to the adjacent cylinder bores and the exhaust port. Since the width is wider than that in the other portions, the load applied to the gasket based on the bolt fastening force is consumed more by the folded portions at the portions where the folded widths are wider than at other portions.

Therefore, the load applied to the bead is reduced at the above-mentioned location where the folding width is widened, compared to the other locations, and the bead is less likely to be sagged or damaged. Even if the load applied to the bead is reduced, the function of the folded-back portion for preventing the leakage of the combustion gas is increased by the width of the folded-back portion, so that the high-pressure gas seal in the combustion chamber is not adversely affected. If the fold width of the fold of the bore edge is widened around the entire cylinder bore, the load is consumed excessively at the fold and the load distribution in the entire gasket cannot be balanced. However, as in the present invention, it is strongly affected by heat around the cylinder bore. If a portion, that is, a portion adjacent to the adjacent cylinder door or a portion adjacent to the exhaust port is made wider than the other portions, the balance of the entire load distribution can be maintained.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to embodiments and with reference to the drawings. FIG. 1 is an exploded cross-sectional view for explaining a mounting state in which the metal gasket for a cylinder head of the present invention is mounted between the joint surfaces of an engine cylinder block and a cylinder head. Reference numeral 1 denotes a cylinder block of a multi-cylinder in-line engine, and pistons 3 are fitted into cylinder bores 2 and 2 arranged in parallel in the cylinder block 1, respectively. The cylinder bores 2 and 2 are covered with a cylinder head 6 mounted on the cylinder block 1 by bolts (not shown), and the combustion chamber 7 is defined by the cylinder head 6, the cylinder bore 2 and the piston 3. The cylinder head 6 is provided with an intake port 8 and an exhaust port 9 facing the combustion chamber 7, and an intake valve (not shown), an exhaust valve (not shown), and the like are provided respectively. 4 is a water jacket.

A cylinder head gasket 11 is mounted between the joint surface 5 of the cylinder block 1 and the joint surface 10 of the cylinder head 6. The cylinder head gasket 11 is an intermediate plate 1 made of a metal plate such as a stainless plate or an iron plate.
2 and outer substrates 13, 13 made of an elastic metal plate such as a stainless plate arranged on both sides of the intermediate plate. The outer substrate 13 and the intermediate plate 12 have substantially the same shape as the joint surface 5 of the cylinder block and the joint surface 10 of the cylinder head, and are provided with cylinder bores 14 provided corresponding to the bores 2 of the cylinder block. Therefore, a through hole such as a water hole and an oil hole described later, a bolt hole through which a bolt is inserted, and the like are provided. The outer substrate 13 is the cylinder bore 1.
4, a bead 17 is provided to surround 4, and the intermediate plate 12 is provided with folds 18 and 19 on the edge of the cylinder bore.

FIG. 2 is a partly cutaway plan view of the embodiment of the metal gasket for a cylinder head of the present invention.
2 is a sectional view taken along line AA and BB of FIG. 2, and FIG. 4 is a sectional view taken along line CC of FIG. The illustrated gasket of the present invention is similar to that described above for FIG.
It is formed by stacking outer substrates 13 on both sides of 2, and has a cylinder bore 14, a through hole 15 such as a water hole or an oil hole, and a bolt hole 16 into which a bolt is inserted. The outer substrate 13 is provided with beads 17 that surround and seal the cylinder bore 14. The outer substrate has a thickness of 0.15 to 0.30 mm, preferably 0.20 mm, and usually, the bead 17 is formed to have a relatively large spring constant, and the plate thickness, bead height, bead The width and the like are selected so that the spring constant is relatively large. On the outer surface side of the outer substrate, that is, on the surface in contact with the joint surface 5 (FIG. 1) of the cylinder block or the joint surface 10 (FIG. 1) of the cylinder head, heat resistance and flexibility such as a rubber coating film are usually provided. 10 ~ 50μ with sealing material
Cover with a thickness of about m. The thickness of the outer substrate, including this sealing material, is preferably selected to be about 0.22 to 0.30 mm.

The intermediate plate 12 has a thickness smaller than that of the outer substrate and is 0.05 to 0.20 mm, preferably 0.10 to 0.
The thickness is 0.15 mm. The intermediate plate 12 has folds at the edges of its cylinder bore 14, but it is located close to the adjacent cylinder bores (near line AA in FIG. 2) and close to the exhaust port of the cylinder head (BB in FIG. 2).
The return width b2 of the return 19 in the vicinity of the line) is made wider than the return width b1 of the return 18 at other locations around the cylinder bore. For example, when the width between the bores of adjacent cylinder bores is 7 mm and the folding width of the folding back 18 is 1.5 mm, the folding back 1
The folding width of 9 is 2.0 mm.

In the example shown in the figure, both the portion adjacent to the adjacent cylinder bore and the portion adjacent to the exhaust port are the folds 19 having a wide fold width. However, the portion adjacent to the adjacent cylinder bore which is most strongly affected by the thermal effect. Alternatively, only the wide folded portion 19 may be formed. Further, even when both the location near the adjacent cylinder bore and the location near the exhaust port are made to have wide folds 19, the fold widths of the folds 19 at both locations are made different, and the fold-back of the location close to the adjacent cylinder bores is made. The width can be made wider. Although the edge of the cylinder bore 14 of the intermediate plate 12 is folded back to the cylinder block side in FIG. 1, it may be folded back to the cylinder head side as shown in FIGS. Further, the bead 17 of the outer substrate 13 shown in the drawing has a bead protruding toward the intermediate plate 12, and the top of the bead is in contact with the intermediate plate. However, the bead protruding direction is the opposite direction, and the bead is attached to the cylinder block or the cylinder head. And the top of the bead projects toward the cylinder block joining surface 5 or the cylinder head joining surface 10.
The bead may be formed so as to come into contact with and be pressed.

[0013]

In the metal gasket for a cylinder head of the present invention, the fold-back of the cylinder bore edge of the intermediate plate is formed so as to have a wide fold-back width at the location near the adjacent cylinder bore and the location near the exhaust port. Therefore, the load applied to the bead surrounding the cylinder bore of the outer substrate is reduced at that portion. The location near the adjacent cylinder bore and the location near the exhaust port are more strongly affected by the heat than the other areas around the cylinder bore and become hot, so that the bead is likely to settle or be damaged. In the present invention, since the load applied to the beat at that portion is reduced as described above, the risk of the fatigue or damage of the beat becomes equal to or less than that of other portions around the cylinder bore. Therefore, the present invention can significantly improve the durability of the gasket as compared with the conventional one.

[Brief description of drawings]

FIG. 1 is an exploded cross-sectional view illustrating a state in which a metal gasket for a cylinder head according to the present invention is mounted between a joining surface between a cylinder block and a cylinder head.

FIG. 2 is a partial cutaway plan view of an embodiment of the gasket of the present invention.

3 is a sectional view of a section taken along the line AA and the line BB in FIG.

4 is a cross-sectional view taken along the line CC of FIG.

[Explanation of symbols]

 11 Cylinder Head Gasket 12 Intermediate Plate 13 Outer Substrate 14 Cylinder Bore 17 Bead 18 Fold Back 19 Fold Back (Wide Width)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Japanese Patent Laid-Open No. 64-58868 (JP, A) Fukukaihei 4-54363 (JP, U) Japanese Patent Publication 2-6379 (JP, B2)

Claims (2)

[Scope of utility model registration request] 1. A metal gasket in which an outer substrate having beads formed of an elastic metal plate and surrounding the cylinder bore is laminated on both sides of an intermediate plate made of a metal plate and having a fold-back at the edge of the cylinder bore. A metal gasket for a cylinder head, characterized in that a folded width is made wider at a position near an adjacent cylinder bore than at other positions. 2. The metal gasket for a cylinder head according to claim 1, wherein the folded back width of the folded back portion of the intermediate plate is wider than that of the other portion even in the portion close to the exhaust port.