JPH0989112A - Exhaust manifold gasket - Google Patents

Abstract

(57) [Summary] [Object] To provide a gasket for an exhaust manifold, which does not deteriorate in sealing performance even when the exhaust manifold is thermally deformed and the flange attached to each branch pipe receives a deforming force that rises irregularly from the gasket. [Structure] In a metal gasket 6 for a multi-cylinder internal combustion engine in which bolt holes 10 are provided in exhaust holes 8 and 9, respectively, a trapezoidal bead 12 is formed in an outer exhaust hole 9 and an arched bead 11 is formed in an inner exhaust hole 8. The bead width of each of the beads 11 and 12 was made wider on the branch root side of the exhaust manifold (not shown) than on the opposite side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust manifold gasket for an internal combustion engine, and more particularly to an exhaust manifold gasket for a multi-cylinder in-line 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 has a normal exhaust manifold 1 including an inner branch pipe 3-1 and an outer branch pipe 3-2 branched from a manifold body 2.
(Indicated simply as 3 when it is not necessary to distinguish each branch pipe) is 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 high-temperature exhaust gas flows through the exhaust manifold 1, the gasket for sealing between the exhaust manifold and the exhaust port is usually a gasket for exhaust manifold (hereinafter simply referred to as a gasket) using a metal plate having high heat resistance. It is known that 6 is used.

[0004]

By the way, 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, and the shape of the vehicle body structure and the inside of the engine room cannot be determined. Restricted by the layout of other devices. Therefore, the deformation of the exhaust manifold 1 when it is brought into contact with hot exhaust gas and thermally expands is not simple, and is subjected to the following various deformation forces.

That is, the exhaust manifold 1 generally receives a deforming force by which the manifold main body 2 warps in a direction in which the outer branch pipe 3-2 moves away from the internal combustion engine 4 from the inner branch pipe 3-1. There is a problem that the flange 7 attached to 3 is slightly inclined with respect to the gasket 6 and receives a deforming force as shown in FIGS. 3 and 4, and the sealing performance of the gasket 6 deteriorates.

The present invention has been made by paying attention to the above-mentioned problems, in which the exhaust manifold is warped to the outside by the high temperature exhaust gas, and the deformation of the flange attached to each branch pipe is uneven. Even in the case, it is an object to provide an exhaust manifold gasket that does not deteriorate in sealing performance.

[0007]

In order to achieve the above object, the exhaust manifold gasket of the present invention is constructed so that the branch pipe of the exhaust manifold reaches each exhaust port in a rising manner from the branch root. A metal gasket for a multi-cylinder in-line internal combustion engine in which bolts for fixing the branch pipe are provided for each exhaust port, and exhaust holes opening in a bead plate are arranged at least approximately linearly, The cross-sectional shape of the bead formed around the hole is a trapezoid on the outside, an arch shape on the center side, and the bead width of each bead is such that the side near the branch root is formed wider than the far side. is there.

A plurality of bead plates can be used.
For example, the beads formed on the two bead plates may be formed at the positions aligned with each other and the protrusion directions of the beads may be opposite to each other. When an exhaust hole is formed in the middle between the outside and the center side as in a 6-cylinder internal combustion engine, the bead shape formed in the middle 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 to make the cross-sectional shape trapezoidal.

Further, the gasket may have a surface plate laminated on the outside of the bead plate. In addition, one surface plate is folded back to the other side so as to prevent the high temperature gas from coming into direct contact with the bead portion, the end is covered, and a laminated thickness adjusting plate is laminated at that time. Can be used as appropriate. To compress the bead, the wider the bead, the trapezoidal cross-section rather than the arched bead, and the wider bead than the narrow bead requires less tightening force. Therefore, the outer bead is trapezoidal, the inner bead is arched, and
The means for forming the bead width of each bead on the side closer to the branch root and on the side farther than the distant side increases the force that suppresses the lifting of the flange due to the deformation of each branch pipe, and thus the deformation of the exhaust manifold is suppressed. It is possible to prevent the deterioration of the sealing performance of each exhaust hole.

[0010]

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

The mounting position of the bolt hole 10 is
As shown in FIG. 1, the exhaust holes 8 and 9 are not uniform, but they are arranged substantially symmetrically 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 the bolts attached to the internal combustion engine (not shown) used. An arc-shaped bead 11 (B in FIG. 2) 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 arch-shaped beads 11 and trapezoidal beads
12 is the protruding direction on each of the bead plates 13 and 14
And the respective exhaust manifolds (not shown).
No.) Branch root side (bottom side of the figure) bead width L₁The opposite
Side (upper side of the figure) bead width L ₂Wider (L₁>
L₂), And the height h is commonly formed, and the face plate 15 is formed 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 in order to make the tightening force constant, a tightening bolt is used with a torque wrench or the like. It was attached to the internal combustion engine (the attached state is not shown). With respect to the tightening, the trapezoidal bead 12 is more easily tightened than the arched bead 11, and each arched bead 11 and the trapezoidal bead 12 are tightened.
The lower side is more easily compressed than the upper side, and the flange is formed so that the tightening force of the bolt acts almost evenly on the whole. Therefore, the bottom of the trapezoidal bead 12 has the most margin for tightening force on each part of the beads 11 and 12,
The top of the arched bead 11 in the figure has the least margin.

On the other hand, as shown in FIG. 4, the flange 7 of the outer branch pipe 3-2 to the inner branch pipe 3-1 of the exhaust manifold 1 is deformed in the direction of separating from the gasket 6 by thermal deformation of the exhaust manifold. Further, each flange 7 has a different deforming force in the direction of separating from the gasket 6 between the lower side and the upper side in the figure. However, in the gasket 6 of the present embodiment, as described above, the reaction force of the bead of the strong portion is formed weaker than the reaction force of the bead of the portion where the separation force is weak, and therefore, the extra force of the tightening force is increased accordingly. The deformation of the exhaust manifold 1 can be suppressed as a whole.
Therefore, the gasket 6 of this embodiment can exhibit reliable and stable sealing performance.

[0015]

As described above, in the exhaust manifold gasket of the present invention, the outer bead in which the thermal deformation of the exhaust manifold is larger is formed in a trapezoidal shape, and the inner bead in which the thermal deformation is smaller is formed in an arch shape. Moreover, since the bead width of each bead is formed so that the side closer to the branch root of the exhaust manifold where the thermal deformation is larger than the far side, the larger the deforming force of each branch pipe, the less force is required to tighten the bead. As a result, the margin to withstand the deformation force increases, the deformation of the exhaust manifold is suppressed, and the deterioration of the sealing performance of each exhaust hole can be prevented.

[Brief description of drawings]

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

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

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

FIG. 4 is a sectional view taken along the line IV-IV of FIG.

[Explanation 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 (exhaust manifold gasket) 7 Flange 8 Inner exhaust hole 9 Outer exhaust hole 10 Bolt hole 11 Arched bead 12 Trapezoidal bead 13 Bead plate 14 Bead plate 15 Face plate L ₁ Bead width L ₂ Bead width h Height

Claims (2)

[Claims] 1. A multi-cylinder internal combustion engine in which a branch pipe of an exhaust manifold is formed so as to rise from a branch root to reach each exhaust port, and a bolt for fixing the branch pipe is provided for each exhaust port. A metal gasket for use in exhaust gas, in which the exhaust holes opening in the bead plate are arranged in at least a substantially linear shape, and the cross-sectional shape of the beads formed around the exhaust hole is trapezoidal on the outside and arched on the center side. An exhaust manifold gasket in which a bead width of each bead is formed so that a side closer to the branch root is formed wider than a far side. 2. The exhaust manifold gasket according to claim 1, wherein the beads formed on the two bead plates are formed at positions aligned with each other, and the protrusion directions of the beads are opposite to each other.