JP2864362B2 - Gasket for exhaust manifold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gasket for an exhaust manifold of an internal combustion engine, and more particularly to a gasket for an exhaust manifold of a multi-cylinder internal combustion engine.

[0002]

2. Description of the Related Art As shown in FIG. 3, an exhaust manifold of a multi-cylinder internal combustion engine is composed of an ordinary exhaust manifold 1 having an inner branch pipe 3-1 and an outer branch pipe 3-2 branched from a manifold body 2.
(When it is not necessary to distinguish each branch pipe, it is simply indicated as 3). The inner exhaust port 5-1 and the outer 5-2 of the internal combustion engine 4
(When it is not necessary to distinguish each exhaust port, it is simply indicated as 5).

Since a high-temperature exhaust gas flows through the exhaust manifold 1, a gasket for sealing between the exhaust manifold and the exhaust port is usually a gasket for an exhaust manifold using a highly heat-resistant thin metal plate (hereinafter simply referred to as a gasket). 6) is known to be used.

[0004]

The shape of the exhaust manifold, particularly the shape of the exhaust manifold for an internal combustion engine mounted on an automobile or other vehicle, cannot be determined independently. Subject to restrictions such as the placement of other equipment. Therefore, the deformation when the exhaust manifold 1 thermally expands by contacting the high-temperature exhaust gas is not simple, and receives various deformation forces as follows.

That is, the exhaust manifold 1 is generally subjected to a deformation force in which the manifold main body 2 warps in a direction in which the outer branch pipe 3-2 is separated from the internal combustion engine 4 from the inner branch pipe 3-1. The flange 7 attached to the gasket 3 is slightly inclined with respect to the gasket 6 and may receive a deformation force as shown in FIGS.

The present invention has been made in view of the above-mentioned problems, and the exhaust manifold is warped outward due to the high-temperature exhaust gas, and the deforming force in which the floating of the flange attached to each branch pipe is uneven is applied. Even in such a case, an object of the present invention is to provide a gasket for an exhaust manifold in which the sealing performance is not deteriorated.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, a gasket for an exhaust manifold according to the present invention is formed so that a branch pipe of the exhaust manifold reaches each exhaust port in a rising shape from a branch base. , a bolt for fixing the branch pipe to the internal combustion engine, provided for each exhaust port, and the exhaust
Ports are arranged almost linearly in the cylinder arrangement direction of the internal combustion engine
And the branch pipes are arranged such that both outer sides are closer to the center than the center side.
The internal combustion engine uses the exhaust heat from the distant side
A metal gasket for a multi-cylinder row internal combustion engine , wherein the branch pipe receives a deforming force warping in a direction away from the metal pipe;
Exhaust holes aligned with the exhaust ports on the bead plate of the
Open, the bead cross-sectional shape formed around the exhaust Kiana, said outer trapezoidal, the center side is formed in an arch shape, the bead width of each bead, the side closer to the branch root, far It is formed wider than the side.

[0008] A plurality of bead plates can be used.
For example, the beads formed on the two bead plates can be formed at positions that match each other and in such a manner that the projecting directions of the beads are opposite to each other. When an exhaust hole is also formed between the outer side and the center side, such as in a six-cylinder in-line type internal combustion engine, the bead shape formed in the intermediate exhaust hole has a bead width wider than the center side. The cross-sectional shape may be arched, or the bead width may be narrower than the outside, and the cross-sectional shape may be trapezoidal.

Further, in the gasket, a surface plate can be laminated outside the bead plate. Also, the same means as the conventional metal-laminated gasket, such as folding one surface plate to the opposite side to cover the end so that the high-temperature gas does not directly contact the bead portion, and laminating a lamination thickness adjustment plate at that time, etc. Can be used as appropriate. To compress the bead, the wider the bead, the trapezoidal in cross-section than the arch and the wider bead than the narrower bead require less clamping force. Therefore, the outer bead has a trapezoidal shape, the inner bead has an arch shape, and
The means for forming the bead width of each bead wider on the side closer to the branch root than on the far side increases the force for suppressing the floating of the flange due to the deformation of each branch pipe, so that the deformation of the exhaust manifold is suppressed. In addition, it is possible to prevent a decrease in sealing performance of each exhaust hole.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The exhaust manifold gasket (hereinafter simply referred to as gasket) 6 of the present embodiment shown in FIGS. 1 and 2 is for a four-cylinder row internal combustion engine, and a bolt hole 10 for fastening the inner exhaust hole 8 and the outer exhaust hole 9 is provided. , Two for each exhaust hole.

The mounting position of the bolt hole 10 is as follows:
As shown in FIG. 1, although not uniform for each of the exhaust holes 8 and 9, both are arranged at substantially symmetric positions with respect to the center of the inner exhaust hole 8 and the outer exhaust hole 9. The arrangement of the bolt holes 10 depends on the position of a bolt attached to an internal combustion engine (not shown) to be used. An arched bead 11 (FIG. 2B) is formed around the inner exhaust hole 8, and a trapezoidal bead 12 (A in FIG. 2) is formed around the outer exhaust hole 9.

These arched beads 11 and trapezoidal beads
12 is the projecting direction on each of the bead plates 13 and 14.
And the exhaust manifolds (shown)
Bead width L on the branch root side (lower side in the figure)₁The opposite
Bead width L on the side (upper side in the figure) _TwoWider (L₁>
L_Two) And the height h is formed in common, and the surface plate 15 is provided on both surfaces.
Were laminated.

The gasket 6 of the present embodiment formed as described above is interposed between the internal combustion engine and the exhaust manifold, and the tightening bolts are fixed by using a torque wrench in order to keep the tightening force constant. It was attached to an internal combustion engine (the attached state is not particularly shown). For this tightening, the trapezoidal beads 12 are more easily tightened than the arched beads 11, and each arched bead 11 and trapezoidal bead 12
The lower side was more easily compressed than the upper side, and the flange was formed such that the tightening force of the bolt acts almost evenly on the whole. Therefore, the tightening force of each part on the beads 11 and 12 has the most margin on the lower side of the figure of the trapezoidal bead 12,
The upper side of the figure of the arched bead 11 has the least allowance.

On the other hand, as shown in FIG. 4, the flange 7 of the outer branch pipe 3-2 from the inner branch pipe 3-1 of the exhaust manifold 1 has a deforming force in a direction separating from the gasket 6 due to thermal deformation of the exhaust manifold. In addition, the deformation force of each flange 7 in the direction in which the flange 7 is separated from the gasket 6 differs between the lower side in the figure and the upper side. However, as described above, the gasket 6 of the present embodiment has a weaker reaction force of the bead in the stronger portion than the bead in the portion where the separation force is weaker. As a whole, the deformation of the exhaust manifold 1 can be suppressed.
Therefore, the gasket 6 of the present embodiment can exhibit a reliable and stable sealing performance.

[0015]

As described above, the gasket for an exhaust manifold of the present invention has a trapezoidal outer bead where the thermal deformation of the exhaust manifold appears larger, and an arched inner bead where the thermal deformation of the exhaust manifold appears smaller. Also, since the bead width of each bead is larger on the side where the thermal deformation is closer to the branch root of the exhaust manifold than on the far side, the larger the deforming force of each branch pipe, the smaller the force required to tighten the bead. Accordingly, a margin for withstanding the deformation force is increased, the deformation of the exhaust manifold is suppressed, and a decrease in sealing performance of each exhaust hole can be prevented.

[Brief description of the drawings]

FIG. 1 is a plan view of a gasket for an exhaust manifold according to an embodiment of the present invention.

2A is a sectional view taken along the line IIA-IIA in FIG. 1, and FIG.
It is a sectional view taken on the line B-IIB.

FIG. 3 is a plan view in which a deformation amount is exaggerated and a part is cut away to explain a problem of an exhaust manifold according to a conventional example.

FIG. 4 is a sectional view taken along line IV-IV in FIG. 3;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Exhaust manifold 2 Manifold main body 3 Branch pipe 3-1 Inner branch pipe 3-2 Outer branch pipe 4 Internal combustion engine 5 Exhaust port 5-1 Inner exhaust port 5-2 Outer exhaust port 6 Gasket (gasket for exhaust manifold) 7 Flange 8 Inside exhaust hole 9 Outside exhaust hole 10 Bolt hole 11 Arched bead 12 Trapezoidal bead 13 Bead plate 14 Bead plate 15 Surface plate L ₁ Bead width L ₂ Bead width h Height

Claims (2)

(57) [Claims] 1. A branch pipe of the exhaust manifold is formed to reach the respective exhaust port to launch like a branch root, a bolt for fixing the branch pipe to the internal combustion engine, provided for each exhaust port, and the exhaust Ports are arranged in the same direction as the internal combustion engine
And the branch pipes are arranged such that both outer sides are on the center side.
And the branch root side is exhausted from the far side.
The deformation force warping in a direction away from the internal combustion engine by heat is applied to the branch.
A metal gasket for a multi-cylinder in-line type internal combustion engine received by a pipe , wherein a bead plate of the metal gasket is connected to the exhaust port.
Open an exhaust hole for alignment, the cross-sectional shape of the bead to be formed around the exhaust Kiana, said outer trapezoidal, the center side is formed in an arch shape, the bead width of each bead, the branch root Exhaust manifold gasket with the near side wider than the far side. 2. The gasket for an exhaust manifold according to claim 1, wherein the beads formed on the two bead plates are formed at positions aligned with each other, and the projection directions of the beads are opposite to each other.