JPH066219Y2 - Metal laminated gasket - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a metal laminated gasket used in an internal combustion engine.

[Prior Art] Conventionally, as a metal laminated gasket used in a diesel engine or the like, for example, there are those disclosed in Japanese Utility Model Publication No. 57-10446 and Japanese Utility Model Publication No. 57-196244. A conventional cylinder head gasket will be described below based on these prior arts.

In a small engine, when the cylinder bore is sealed with a cylinder head gasket, some cylinders use the upper end portion of the cylinder liner as a seal portion.However, in a normal engine, a flange portion is provided at the upper end portion of the cylinder liner, and the collar portion is provided. Is generally mounted on a cylinder block and assembled to the cylinder block, and the collar portion is generally used as a seal portion. in this case,
When the diameter of the cylinder hole of the cylinder head gasket is larger than the diameter of the cylinder bore, there is a problem that a dead space occurs and the volume of the combustion chamber substantially increases.

Since the compression ratio decreases as the volume of the combustion chamber increases in this way, in order to prevent this, in the device of the above-mentioned Japanese Utility Model Laid-Open No. 57-196244, a fire ring is provided in this portion or a gasket is used. There is disclosed a metal laminated gasket having an auxiliary seal portion formed by extending to a portion of the above portion, the extension portion having a bead having a height lower than that of the bead provided on the flange portion of the cylinder liner.

However, the beads generate the reaction force against the compression in a narrow region, and it is difficult to make the elastic force of the main seal portion and the elastic force of the auxiliary seal portion sufficiently different from each other. Therefore, it is difficult to increase the seal pressure as much as possible without damaging the cylinder liner in the auxiliary seal portion.

Further, in the invention of Japanese Utility Model Laid-Open No. 57-10446, the auxiliary seal portion is formed by folding one surface plate back to form a hollow portion,
A metal plate is formed by bending it in a wave shape so that the peaks and valleys reach the cylinder head and the cylinder body, or a hollow ring-shaped auxiliary seal part is formed by a separate part with the metal plate, and heat resistant rubber is inside. A gasket filled with an elastic material such as or asbestos is disclosed.

However, the hollow portion cannot increase the reaction force against compression, and the corrugated auxiliary seal portion serves the purpose of the auxiliary seal portion that reduces the combustion chamber volume once the sealing performance deteriorates due to heat deterioration or the like. In addition to the problem that the number of parts increases, the ring-shaped auxiliary seal part using the filler cannot be achieved, and heat-resistant rubber cannot be used around the combustion chamber. However, there is a problem that the elastic force is insufficient and a sufficient effect cannot be obtained.

Therefore, a gasket is arranged on the flange so as not to form the dead space, and a bead (convex portion) that generates a sealing force is provided on the entire surface of the arranged portion.
There is a device of Japanese Patent No. 32-10102. This prior art gasket is a gasket in which two bead plates each having a ring-shaped and a plurality of beads concentric with a cylinder hole are stacked and sandwiched between metal plate grommets, and the gasket is placed on the collar portion. Is what you use.

However, since this gasket applies uniform pressure to the entire surface of the flange, a downward force acts on the body of the cylinder liner. Therefore, there is a problem that stress is generated in the root portion of the collar portion provided on the cylinder liner, and a crack is generated in the root portion during long-term use.

As a similar prior art, there is an invention of Japanese Utility Model Laid-Open No. 59-47343, in which a sealing force is exerted on almost the entire surface of the cylinder liner and the flange portion in the ordinary cylinder head gasket arranged on the entire surface of the cylinder head as described above. . In this prior art, a gasket is formed so as to eliminate the dead space as in each of the above prior arts, and various kinds of beads such as normal beads, firing, and bent metal plates are used.

In the figures shown in this publication, there are many examples in which the site where the sealing force is generated is located closer to the inner edge of the cylinder hole, and during long-term use as in the prior art of the above publication. There is a risk of cracking at the base of the collar.

Therefore, the invention of Japanese Utility Model Publication No. 55-12016, in which a cylinder hole of an asbestos gasket is provided so as to eliminate the dead space, and the flange side is thicker than the opening edge side so that the load applied to the flange side is larger than the opening edge side There is. However, the prior art of this publication has a problem that it cannot be applied to a high-performance internal combustion engine because it has poor heat resistance because it uses asbestos.

[Problems to be solved by the device]

The present invention has been made focusing on the above problems,
An object of the present invention is to provide a metal laminated gasket in which the dead space of the combustion chamber is reduced as much as possible, the flange portion of the cylinder liner is prevented from being damaged, and the gasket sealing property is remarkably improved.

[Means for Solving the Problems]

In order to achieve the above object, the metal laminated gasket of the present invention has a structure in which a main bead for applying a sealing load is provided on a seal part provided on a cylinder liner, and at least a surface plate is a cylinder hole from the main bead part. Side to form an auxiliary seal portion, and the auxiliary seal portion is a portion in which the extended face plate covers the gasket disposable portion on the cylinder liner, and is brought close to each other to face the opposite face plate. The total thickness of the plates folded back so as to overlap and laminated on the auxiliary seal portion is made thinner than the total thickness of layers laminated on the portion where the main beads are provided.

[Action]

The auxiliary seal portion of the present invention, which is formed to reduce the dead space of the combustion chamber, when compressed, interferes with each other when the folded portions that are folded back to the opposite side bend, and bends more than a single case. Has the effect of increasing the elastic repulsion force against.

〔Example〕

An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a metal laminated head gasket body 4 of the embodiment.
FIG. 3 is a cross-sectional view of a main part of FIG. 1, in which the gasket 4 is provided with an intermediate plate 6 consisting of three pieces between two surface plates consisting of a surface plate 5 (hereinafter referred to as an upper plate) and a surface plate (hereinafter referred to as a lower plate) 7. It has a configuration. The middle plate 6 is two reinforcing plates 6 having the same thickness.
Reinforcement plate 6c consisting of a and 6b and a thin plate arranged between them
It consists of and. Main beads 8a and 8b are provided on the reinforcing plates 6a and 6b, respectively, and the beads are arranged so as to overlap each other in opposite directions.

The upper plate 5 and the lower plate 7 are respectively extended to the cylinder hole side and folded back, and are overlapped with each other so as to provide a space inside, thereby forming an auxiliary seal portion 8c. The auxiliary seal portion 8c, which is formed by the folded back portion, has a structure that the main beads 8a, 8a are opposed to the compressive force applied from both sides of the gasket 4.
The elastic force to resist becomes weaker than b.

The sealing action of the above embodiment will be described with reference to FIG. 2 which is shown by another head gasket having a different structure but having the same action.

FIG. 2 is a diagram for explaining a seal load distribution state.
Is a cylinder block, 2 is a cylinder liner, and 3 is a cylinder head. Between the upper surfaces of the cylinder block 1 and the cylinder liner 2 and the lower surface of the cylinder head 3, a metal laminated type gasket body 4 is provided. It is installed. The cylinder liner 2 includes a collar portion 2a that engages with a step portion 1a formed on the cylinder block 1 (this collar portion 2a serves as a seal portion of the gasket body 4), and an annular protrusion 2b formed on the inner top portion thereof. And the cylinder hole diameter d of the gasket body 4 is the outer diameter D of the annular protrusion 2b.
Is configured to be close to. The gasket body 4 is composed of an upper plate 5, an intermediate plate 6 for reinforcement, and a lower plate 7. The tip of the lower plate 7 is bent in an arc shape and overlaps with the tip of the upper plate 5. The reinforcing middle plate 6 includes two reinforcing plates 6a and 6b having substantially the same thickness as the plate thickness t ₁ of the upper plate 5 and the lower plate 7,
The reinforcement plate 6c of the thin plate t ₂ and the two reinforcement plates 6a and 6b located on the collar portion 2a of the cylinder liner 2 that engages with the step portion 1a of the cylinder block 1 are connected to the cylinder head 3 from the cylinder head 3. Beads 8a and 8b for receiving and sealing the concentrated load W of are formed. Also in a portion adjacent to the annular projection 2b side, the reinforcing plate 6c of the thin plate t ₂ to form a bead 8c, seals to support lighter pressure and the cylinder head 3 from the combustion chamber 9.

That is, the dead space generated between the gasket body 4 and the annular projection 2b of the cylinder liner 2 is sealed by the bead 8c formed on the thin plate reinforcing portion 6c with a light elastic force, so that the flange of the cylinder liner 2 is sealed. The concentrated load is prevented from acting on the corner portion of the portion 2a.

As described above, in the strong portion of the cylinder liner 2, the beads 8a, 6a, 6b of the thick reinforcing plates 6a, 6b,
In addition to the sealing by 8b, the bead 8c formed on the thin reinforcing plate 6c seals the weak portion.

[Effect of device]

Since the metal laminated gasket of the present invention is configured as described above, the elastic repulsive force of the auxiliary seal portion that reduces the dead space of the combustion chamber can be increased within a range that does not damage the cylinder liner. Therefore, it can be advantageously applied to a head gasket for a high performance internal combustion engine in which the pressure in the combustion chamber becomes high.

Moreover, the present invention does not require a new part to form the auxiliary seal portion, and can be implemented without changing the manufacturing process of the conventional metal laminated gasket.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a metal laminated gasket according to an embodiment of the present invention, and FIG. 2 is a view for explaining a seal load distribution state. 1 ... Cylinder block, 2 ... Cylinder liner, 2a ...
Collar part, 3 ... Cylinder head, 4 ... Gasket body, 5 ...
Surface plate (upper plate), 6 ... Middle plate, 7 ... Surface plate (lower plate), 8
a, 8b ... Main bead, 8c ... Auxiliary seal part.

Claims (1)

[Scope of utility model registration request] 1. A main bead for applying a sealing load is provided on a seal part provided on a cylinder liner, and at least a surface plate is extended from the main bead part to a cylinder hole side to form an auxiliary seal part. The seal portion is a portion in which the extended surface plate covers the gasket disposable portion on the cylinder liner, is brought close to each other, is folded back so as to overlap the opposite surface plate side, and is laminated on the auxiliary seal portion. A metal laminated gas gasket with a total thickness that is thinner than the total thickness of the plates laminated on the part where the main beads are provided.