JPH04347065A - Metallic gasket - Google Patents

Abstract

PURPOSE:To impact a stopper function even though a space between bores is too narrow to provide a stopper. CONSTITUTION:In a metallic gasket for internal combustion engine, a partial shim plate 6 is provided parallel from the end 2 of a combustion chamber, at the recessed surface side of a bead 3, and it is fixed 7 at the flat part near the combustion chamber side.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal gasket that is installed at the joint surface between a cylinder head and a cylinder block of an internal combustion engine to prevent leakage of combustion gas, cooling water, lubricating oil, etc.

0002

2. Description of the Related Art A metal gasket has a structure in which a number of combustion chamber holes corresponding to each combustion chamber are provided on an elastic substrate, and concentric beads are provided around the periphery of the combustion chamber holes. FIG. 7 is a partially cutaway sectional view of a metal gasket, and a conventional example will be explained using this diagram. In the figure, 1 is an elastic substrate, and the left end 2 is the combustion chamber hole 2' (
(not shown in FIG. 7). A bead 3 is formed in a convex shape with a flat portion 4 remaining at the peripheral edge of the combustion chamber hole. A stopper 5 is provided on the flat part 4,
The stopper can be overlaid by thermal spraying or fixed to a shim plate, and has the function of preventing fatigue failure due to bead vibration.

0003

[Problem to be Solved by the Invention] In recent years, engines have become smaller, lighter, and more efficient, and as a result, the gap between the bores has become extremely narrow, and the seal width of the gasket has become 5.
Some of them are smaller than mm, and the above-mentioned conventional techniques are no longer able to handle them. In other words, the bead width is determined by the amount of deformation following the engine rigidity, and is 2.0 mm.
This is because if the bead width is less than that, the following amount is insufficient, and if the bead width is made wider, stoppers cannot be provided on the flat portions at both ends of the bead.

[0004] Furthermore, even if a stopper is provided,
This is because the width of the stopper is too narrow and an extremely large surface pressure is applied to it, and when the heat generated during operation adds to the expansion of the engine, the pressure becomes even higher. In addition, the repeated loads due to vibrations and the fact that the engine is made of aluminum create dents on the engine surface, resulting in a loss of stopper effect. The present invention has been made to solve the above-mentioned drawbacks, and an object of the present invention is to provide a metal gasket that does not lose its stopper effect even when the distance between the bores is narrow. [Structure of the invention]

[0005]

Means for Solving the Problems The basic configuration of the present invention will be explained with reference to FIG. First, in the present invention, a bead 3 is provided on an elastic substrate 1, and a shim plate 6 is fixed at a fixing point 7 to the concave surface of the bead. In this case, the shim plate to be fixed is not provided on the entire surface of the board 1, but experiments have been conducted to find that fatigue failure is least likely to occur when the width is 55% or more and 70% or less of the bead width from the end 2 of the bore. Confirmed at. That is, instead of the stopper provided on the convex flat portion of the bead, a shim plate is provided on the concave side of the bead to function as a stopper.

Next, the operation will be explained. When the gasket configured as described above is tightened, it deforms as shown in FIG. 3. Figure 3
As can be seen from Figures (a) and (c), the half of the bead closer to the bore is fully bent, and the remaining half is not fully bent. Even if the part of the bead that contacts the shim plate bends completely, the remaining part does not bend completely, so this part has sufficient resilience.
This will ensure durability. The pressure distribution is shown in Figure 3 (
b) and Fig. 3(d), and it can be seen that they are sufficiently densely covered. Moreover, FIG. 3(a) shows the state between the bores, and FIG. 3(c) shows the other state.

[0007]

[Embodiment] An embodiment will be described below with reference to the drawings. Figure 2
7 is a cross-sectional view of one embodiment of the metal gasket according to the present invention, and the same parts as those in FIG. 7 are given the same reference numerals and the description thereof will be omitted. FIG. 4 is a schematic plan view with a part of the metal gasket cut away, and A-A' in the figure is FIG.
-B' is Fig. 2(a), and C-C' is Fig. 2(b).
It is. First, the outline of the planar configuration shown in FIG. 4 will be briefly explained. In FIG. 4, 10 is a metal gasket main body, which is made of an elastic substrate 1. The elastic substrate 1 has an opening 2' provided corresponding to the combustion chamber, and beads 3 (tops indicated by dashed-dotted lines) 3 are provided concentrically at the outer edge of the opening 2'. 8 is a bolt hole for tightening, 9 is a water hole for cooling water circulation, and 11 is an oil hole.

FIG. 2(a) shows a state diagram between the bores, and since it is a B-B' cross section, the left side is the #1 bore and the right side is the #1 bore.
It is 2 bore. And because the distance between the bores is narrow, one bead 3
are shared. In this case, the #1 side bore has a shim plate 6.
-1 and fix the shim plate 6-2 to the bore on the #2 side. The width of the shim plate is 25±10 of the bead width from the flat part.
% long. Note that the numerical values of the shim plate mentioned above were confirmed from experimental results, and according to this embodiment, even in a narrow bore gap, a sufficient sealing effect can be obtained as in the case of a stopper. Note that the thickness of the shim plate is thinner than that of the substrate.

FIG. 5 is a sectional view showing the structure of another embodiment. In this embodiment, a shim plate 6 is fixed to a substrate 1-1 at a fixing point 7, and another substrate 1-2 is arranged at a symmetrical position. According to this embodiment, it is possible to cope with the case where the absolute amount of deformation of the engine is large. Further, FIG. 6 is a diagram showing that when the entire thickness of the gasket is desired, a sub-plate 12 of the necessary thickness is sandwiched in the middle, and the reference numerals in the diagram correspond to those in FIG. 5.

0010

As explained above, according to the present invention, a gasket for an internal combustion engine has a structure in which a partial shim plate is fixed to the concave surface of the bead, so that a stopper function can be added even between narrow bores. It is possible to do so.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the basic configuration of the present invention.

FIG. 2 is a configuration diagram showing the space between bores in an embodiment of the present invention.

FIG. 3 is a diagram showing the operation of the present invention.

FIG. 4 is a schematic diagram showing a planar configuration of a metal gasket.

FIG. 5 is a cross-sectional configuration diagram of an embodiment of the present invention.

FIG. 6 is a cross-sectional configuration diagram of another embodiment.

FIG. 7 is a sectional view illustrating a conventional metal gasket.

[Explanation of symbols]

1, 1-1, 1-2 Board 2 Combustion chamber hole end 2' Combustion chamber hole 3, 3-1, 3-2 beads 4 Flat part 5 Stopper 6 Shim board 7 Fixed point 8 Tightening hole 9 Water hole 10 Metal gasket body 11 Oil hole

Claims (4)

[Claims] 1. A metal gasket comprising a substrate with a bead formed on the periphery of a combustion chamber hole, in which a partial shim plate is provided from an end of the combustion chamber on the concave side of the bead,
A metal gasket characterized by being fixed at a flat part near the combustion chamber. 2. The metal gasket according to claim 1, wherein the shim plate has a width from 55% to 70% of the bead width from the end of the combustion chamber on the concave side. 3. The metal gasket according to claim 1, wherein a substrate having no shim plate is disposed symmetrically with respect to a substrate having a shim plate. [Claim 4] When the combustion chamber has a plurality of holes and the bead is shared between cylinders, the width of the shim plate is 25% ± 10% of the bead width from the center of the bead to the flat part closer to the bore. A metal gasket characterized in that each shim plate is fixed at a flat part near the combustion chamber.