JPH10213011A - Cylinder head gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide satisfactory sealed properties even though a counter side connecting surface has cavities and blemishes, by bringing a full bead part and a half bead part in pressure contact with a counter member at high bearing pressure, and besides in a relatively wide contact area, by a projected part. SOLUTION: A cylinder head gasket 1 is equipped with two gasket base plates 3 having combustion chamber holes 3A, and full bead parts 3a and half bead parts 3b which are respectively arranged on these gasket base plates 3. The full bead parts 3a and the half bead parts 3b on the respective gasket base plates 3 are successively held along the circumferential direction of a cylinder bore 2 between the cylinder head 5 and the cylinder block 6 by a projected part 6a which is arranged to at least one of the cylinder head 5 or the cylinder block 6 and endlessly surrounds the circumference of the cylinder bore 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an engine cylinder head gasket.

[0002]

2. Description of the Related Art Conventionally, as a cylinder head gasket, two gasket substrates sandwiched between a cylinder head and a cylinder block and having a combustion chamber hole formed in accordance with a cylinder bore are arranged around the cylinder bore. There is a known type that includes a spacer that surrounds this endlessly and that is sandwiched between the two gasket substrates, and a full bead portion or a half bead portion provided at an appropriate position on the gasket substrate (actually). JP-A-4-71865, JP-A-4-165167). Conventionally, instead of providing a bead on the cylinder head gasket,
Alternatively, a cylinder head or a cylinder block provided with a projection for endlessly surrounding the cylinder bore together with the bead portion is also known (JP-A-56-47643).
JP-A-5-96633).

[0003]

The spacer which surrounds the periphery of the cylinder bore in an endless manner is provided to increase the surface pressure at that portion to improve the sealing performance.
If there are cavities or scratches on the mating surface of the mating side, the cavities or scratches are easily affected by the cavities or scratches, and there is a risk that the sealing performance may be reduced. In the case where the cylinder head or the cylinder block is provided with a projection that surrounds the periphery of the cylinder bore in an endless manner, the surface pressure of the seal portion can be increased, but since the seal portion is linear, sufficient No sealing effect was obtained. In view of such circumstances, the present invention is to provide a cylinder head gasket in which good sealing performance is always obtained even if there is a cavity or a flaw in a mating surface of a mating member, and a sealing portion is planar. .

[0004]

That is, the present invention provides a plurality of gasket substrates sandwiched between a cylinder head and a cylinder block and having a plurality of combustion chamber holes formed in accordance with the cylinder bores. The gasket substrate includes a full bead portion and a half bead portion, and the full bead portion and the half bead portion of the gasket substrate are provided on at least one of the cylinder head and the cylinder block, and the projection portion surrounding the cylinder bore endlessly includes the cylinder. It is characterized by being continuously held between the head and the cylinder block along the circumferential direction of the cylinder bore.

[0005]

According to the above construction, when the full bead portion and the half bead portion of each gasket substrate provided around the combustion chamber hole are sandwiched between the cylinder head and the cylinder block, the full bead portion and the half bead are formed by the projecting portion. The portion can be pressed against the mating material in a planar manner with a high surface pressure and a relatively large contact area. As a result, even if there is a cavity or a flaw on the mating surface of the mating member, it is less likely to be affected by such a cavity and a good sealing performance can be secured.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a cylinder head gasket for an in-line four-cylinder engine will be described below. 1 and 2, a cylinder head gasket 1
Is provided with two gasket substrates 3 each having four combustion chamber holes 3A drilled in accordance with the cylinder bore 2 (see FIG. 1).
A full bead portion 3a and a half bead portion 3b surrounding each combustion chamber hole 3A are formed. The full bead portion 3a and the half bead portion 3b are formed in that order from the center side of each combustion chamber hole 3A to the outside, and protrude toward the side opposite to the superposed side of each gasket substrate 3. It is formed. Each gasket substrate 3 has a thickness of 0.20 mm.
Thick SUS301-H can be used, and as shown in FIG. 3, it is preferable to coat both surfaces with a coating layer 3c such as NBR.

As shown in FIG. 1, the cylinder head gasket 1 is interposed between a cylinder head 5 and a cylinder block 6 of an engine, and integrally connects the cylinder head 5 and the cylinder block 6 by fastening bolts 7. As a result, they are sandwiched between them to seal between them. At this time, the cylinder head 5
And at least one of the cylinder block 6
In the illustrated embodiment, a protruding portion 6a is formed on the cylinder block 6 side so as to surround the periphery of each cylinder bore 2 endlessly. The height h of the projection 6a is 0.08 m
m is desirable. Further, in the illustrated embodiment, the protrusion 6a is provided with a space between the cylinder bores 2 and, accordingly, each combustion chamber hole 3.
A, the distance between the four projections 6 is small.
"a" are mutually connected between the adjacent combustion chamber holes 3A to be integrally formed. When the interval between the combustion chamber holes 3A is large, it is a matter of course that four projecting portions 6a may be separately formed. The full bead portion 3a and the half bead portion 3b of each gasket substrate 3 are located between the cylinder head 5 and the protruding portion 6a of the cylinder block 6,
The half bead portion 3b which is continuously sandwiched in the circumferential direction of the cylinder bore 2 and breaks the continuity in the circumferential direction, or a part of the half bead portion 3b which is outside protrudes outward from the protruding portion 6a, and the Care is taken to ensure that pinching is not impossible. Further, in the illustrated embodiment, the cylinder head 5 and the cylinder block 6 are formed as an open deck block made of aluminum die-cast, and the cooling water passages 5a and 6b formed in the cylinder head 5 and the cylinder block 6 are the most common. Half bead 3 on the outside
Outside of b, they are formed on the joint surfaces of the cylinder heads 5 and the cylinder blocks 6 so as to integrally surround the four combustion chamber holes 3A.

According to the above construction, the periphery of each combustion chamber hole 3A can be endlessly surrounded by the full bead portion 3a and the half bead portion 3b. Since the projection 6a is provided, the full bead 3a and the half bead 3
b can be pressed against the cylinder head 5 and the cylinder block 6 with a high surface pressure and a relatively large contact area. As a result, even if there are cavities or scratches on the joint surface between the cylinder head 5 and the cylinder block 6, the effects are less likely to be caused by such cavities or scratches, and good sealing performance can always be ensured.

[0009]

As described above, according to the present invention, even if there is a cavity or a flaw on the mating surface of the mating part, the planar sealing portion is less susceptible to such effects, and good sealing performance can be obtained. The effect of being able to secure is obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a plan view of the cylinder head gasket 1 of FIG.

FIG. 3 is an enlarged sectional view of a main part of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cylinder head gasket 2 ... Cylinder bore 3 ... Gasket main body 3A ... Combustion chamber hole 3a ... Full bead part 3b ... Half bead part 3c ... Coating layer 5 ... Cylinder head 6 ... Cylinder block 6a ... Projection part 5a, 6b ... Cooling water passage

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kenichi Yamaguchi 3-65 Midorigaoka, Toyota City, Aichi Prefecture Inside Daitoyo Kogyo Co., Ltd. (72) Inventor Kazuya Nakata 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation

Claims (3)

[Claims] 1. A gasket substrate sandwiched between a cylinder head and a cylinder block and having a combustion chamber hole drilled in accordance with a cylinder bore, a full bead portion and a half bead portion provided on the gasket substrate, A full bead portion and a half bead portion of the gasket substrate are provided on at least one of the cylinder head and the cylinder block, and are provided with a protruding portion surrounding the cylinder bore endlessly, thereby forming a cylinder bore between the cylinder head and the cylinder block. Characterized in that the cylinder head gasket is continuously held along the circumferential direction of the cylinder head. 2. The cylinder head gasket according to claim 1, wherein the gasket substrate is covered with a covering layer. 3. An open deck block in which a cooling water passage surrounding a full bead portion and a half bead portion of the gasket substrate is formed in at least one of the cylinder head and the cylinder block. The cylinder head gasket according to claim 1 or 2.