JPH0744850Y2 - 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 an engine cylinder head.

[0002]

2. Description of the Related Art As a cylinder head gasket to be inserted and mounted between an engine cylinder block and a cylinder head, as shown in a sectional view of FIG. 4, a bending 18 is provided on an edge of a cylinder bore 14 made of a metal plate. A metal gasket is used in which an intermediate plate 12 and an outer substrate which is disposed on both sides of the intermediate plate and is provided with a bead 17 made of an elastic metal plate and surrounding the cylinder bore 14 are laminated. This metal gasket is intended to seal the high pressure gas in the cylinder bore by the surface pressure obtained by the bead surrounding the cylinder bore 14 of the outer substrate 13, but the fold-back provided on the edge of the cylinder bore 14 of the intermediate plate 12 is inside the bore. The bead is protected from direct hit of high temperature gas caused by lifting of the cylinder head by explosive gas pressure and repeated load or hitting to prevent the bead from settling or being damaged, thereby enhancing 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 that is mounted between the cylinder block and the cylinder head of a multi-cylinder engine, the combustion heat from the cylinder is received from both sides between the adjacent cylinder bores, that is, between the bores. It is most affected by heat and becomes hotter than other parts. Therefore, at the bead portion located between the bores of the beads surrounding the cylinder bore of the outer substrate, the bead is likely to be sagged 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 is more affected by heat than other parts around the cylinder bore, and the bead is liable to be worn or damaged. The means for preventing sagging or damage is reinforced as compared with other parts, thereby improving the durability of the cylinder head gasket.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is designed such that the folds of the cylinder bore edges provided in the intermediate plate are provided between the bores of adjacent cylinder bores or between the bores of adjacent cylinder bores and close to the exhaust port. It is double-folded at the place to be.

[0006]

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.
A bead 17 surrounding 4 is provided, and the intermediate plate 12 is provided with a fold back 18 and a double fold back 19 on the edge of the cylinder bore.

FIG. 2 is a partially cutaway plan view of an 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,
It preferably has a thickness of 0.20 mm, usually bead 1
7 is formed so that the spring constant is relatively large, and the plate thickness,
The height of the bead, the width of the bead, etc. are selected to make the spring constant 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. The sealing material has a thickness of about 10 to 50 μm. 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 between the bores of adjacent cylinder bores (near the line AA in FIG. 2) and in the vicinity of the exhaust port of the cylinder head (line BB in FIG. 2). 3), the folds are double folds 19 as shown in FIG. 3, and the folds of the edges in other portions around the cylinder bore 14 are single folds 18 as in the prior art.

In the illustrated example, the double folds 19 are provided both between the bores and in the portion close to the exhaust port, but it is no problem if the double folds 19 are provided only between the bores that are most strongly affected by the thermal effect. Even when both the space and the portion close to the exhaust port are double-folded back, the width of the folded back may be different between the bore and the portion close to the exhaust port. 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. Also, the bead 17 of the outer substrate 13 shown
Has a bead protruding toward the intermediate plate 12 and the top of the bead is in contact with the intermediate plate. The bead protrudes in the opposite direction, and the bead projects toward the cylinder block or the cylinder head. The bead may be formed so as to come into contact with and be pressed against the joint surface 5 or the joint surface 10 of the cylinder head.

[0011]

In the metal gasket for a cylinder head of the present invention, when the cylinder head is lifted by the explosive gas in the combustion chamber during operation of the engine, it is repeatedly added to the bead surrounding the cylinder bore of the outer substrate. Folding of the cylinder bore edge of the intermediate plate, which has the function of limiting the vibration amplitude of load and striking and preventing bead fatigue and damage, is the strongest thermal influence around the cylinder bore, and between the bores of adjacent cylinder bores, Similarly, since the double folds are formed in the portions close to the exhaust port that are strongly affected by the thermal effect, the increase in wall thickness t ₂ (FIG. 3) due to the folds in these portions causes a single overlap in the other portion of the cylinder bore edge. Is larger than the increase in wall thickness t ₁ (FIG. 4) due to the folding back. Therefore, in the space between the bores and in the portion close to the exhaust port, the vibration amplitude of the repeated load and the beating applied to the bead due to the explosive gas is more limited and weakened than in other portions around the cylinder bore.

A portion between the bores and a portion in the vicinity of the exhaust port are more strongly affected by heat than the other portions around the cylinder and become high in temperature,
Originally, in the present invention, since the repeated load applied to the bead and the vibration amplitude of the beating are weakened as compared with the other parts, in spite of the fact that the bead is liable to be damaged or damaged, in the present invention, The risk of bead sagging or damage is equal to or less than other parts around the cylinder bore. Therefore, according to the present invention, the durability of the cylinder head gasket can be remarkably improved as compared with the conventional case.

[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 Folding Back 19 Double Folding Back

Continuation of the front page (56) References JP-A-64-73157 (JP, A) Actually open 1-56548 (JP, U) Actually open 4-54363 (JP, U) Japanese Patent Publication 2-6379 (JP , B2)

Claims (2)

[Scope of utility model registration request] 1. An outer substrate having a plurality of cylinder bores and an intermediate plate laminated together, wherein the outer substrates arranged on both sides of the intermediate plate are elastic metal plates having beads surrounding the cylinder bore, and the intermediate plate is What is claimed is: 1. A metal gasket for a cylinder head, the metal plate having a fold-back on the edge of the cylinder bore, wherein the fold-back of the intermediate plate is double-folded between the bores of the adjacent cylinder bores. 2. The metal gasket for a cylinder head according to claim 1, wherein the intermediate plate is doubled even at a position close to the exhaust port.