JPH08232759A - Metallic gasket for exhaust manifold - Google Patents

Abstract

PURPOSE: To prevent the occurrence of of permanent set of a bead by avoiding full compression of the bead of a bead base sheet and to improve durability by arranging a stopper bead at a bead base sheet. CONSTITUTION: A metallic gasket for an exhaust manifold comprises a bead base sheet 1 formed of a resilient metallic sheet and beads 4 wherein the hole 7 side is displaced along holes 7 juxtaposed are respectively formed on the bead base sheet 1. The bead 4 is provided in a bead region, extending from the rise part 6 of the bead 4 along a hole 7 side, with a stopper bead 5 protruded in a direction reverse to the protrusion direction of the bead 4 and having height below the displacement height of the bead 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust manifold metal for a multi-cylinder internal combustion engine, which is clamped and fixed between an end surface of an exhaust manifold mounting flange and a wall surface of an exhaust opening formed in a cylinder head. Regarding gaskets.

[0002]

2. Description of the Related Art Conventionally, a metal laminated gasket for an exhaust manifold of an internal combustion engine, which is sandwiched between an end face of a mounting flange of an exhaust manifold and a side face of a cylinder head having an exhaust discharge port and is tightened with a tightening bolt or the like. Is provided so that exhaust gas does not leak from the contact surface between the cylinder head and the exhaust manifold, and various types of manifold gaskets are used.

As a typical type of gasket, there is a metal laminated gasket for manifold of a type in which metal plates are laminated. The metal plate laminated gasket is generally formed by laminating 3 to 5 metal plates. Odd number of sheets, for example
Regarding the three metal plate laminated gasket, the metal plate in the center is a flat steel plate having no beads, and the metal plates on both sides thereof are bead plates in which the bead portions are raised so as to be away from each other. Regarding such a metal plate laminated gasket, for example, Japanese Utility Model Laid-Open No. 2-61169 and Japanese Utility Model Publication No.
There is one disclosed in Japanese Unexamined Patent Publication No. 61170.

Alternatively, for an even number of laminated gaskets, for example, four laminated gaskets, two bead plates, which are raised so that the bead portions are spaced apart from each other, are superposed, and two pairs of the superposed bead plates are superposed. can do. Or in the case of a laminated gasket consisting of 5 metal plates, 4
A flat metal plate having no bead portion is interposed in the center of each metal plate. In the metal plate laminated gasket as described above, regarding a metal plate having a bead portion, the bead portion bends and rises from the flat plate portion in a free state, inclines obliquely, bends in the opposite direction, and again becomes parallel to the flat plate portion. Is configured to be.

[0005]

By the way, a metal plate laminated gasket having a structure in which several thin metal plates are stacked as described above is excellent in flexibility and heat resistance,
It has a moderate compressibility by incorporating a bead structure. When the metal plate laminated gasket including the bead plate having the bead portion configured as described above is sandwiched between the joint surfaces of the cylinder head and the exhaust manifold and tightened with a tightening bolt or the like, the bead portion is A seal line is formed on the joint surface of the exhaust manifold to effectively prevent the exhaust gas from leaking from the joint surface. Since the metal plate laminated gasket is economically less likely to deteriorate in sealing performance, it is extremely advantageous in terms of sealing as a gasket for an exhaust manifold having a large thermal expansion at high temperature.

However, although the conventional metal gasket has the above-mentioned advantages, it has the following problems. In other words, recent engines are being pursued to be smaller, lighter and have higher output directivity, and in order to reduce size and weight, the cylinder head is made of aluminum alloy and the exhaust manifold is made lighter. It is required to increase the exhaust gas temperature as one means for improving the performance. When the cylinder head is made of aluminum alloy, the thermal expansion / contraction of the cylinder head increases due to the temperature change accompanying the operation of the internal combustion engine.
If the exhaust manifold is made thinner, the gasket mounting surface,
That is, the amount of thermal deformation of the mounting flange portion increases. When the exhaust gas temperature is raised to a high temperature, the temperature rise of the exhaust manifold further promotes the thermal deformation of the exhaust manifold. For metal plate laminated gaskets, these conditions are severe in terms of temperature and stress, and the limit is pursued to what extent the joint surface between the cylinder head and the exhaust manifold, which causes large thermal deformation, can be followed. become. From such a background, as for the metal gasket for manifold, the demand for the high temperature gasket is increasing.

Therefore, when a stainless steel plate is used for the metal gasket, the material itself has durability including heat resistance, but when exposed to a large temperature change,
The temperature difference between the cylinder head and the exhaust manifold changes significantly in accordance with various operating conditions including engine stop, which results in a large thermal expansion difference between the cylinder head and the exhaust manifold, that is, a relative displacement amount, The residual bead height of the bead portion of the metal gasket decreases, or the bead portion cracks as a result of repeated stress on the metal gasket, resulting in deterioration of sealing performance such as exhaust gas leakage. There is an unavoidable problem.

An object of the present invention is to solve the above-mentioned problems. Even if the exhaust gas is used at high temperature and under severe thermal stress conditions, the bead formed on the elastic metal plate may not be settled or cracked. With a structure that does not easily generate, in particular, by providing a full bead stopper bead along the hole side from the rising part of the bead, it is possible to prevent the bead from being fully compressed and prevent bead settling, cracking, etc. To provide a highly durable metal gasket for an exhaust manifold.

[0009]

In order to achieve the above object, the present invention is constructed as follows. That is, the present invention is for an exhaust manifold composed of a bead substrate made of an elastic metal plate sandwiched and fixed between the end surface of the mounting flange of the exhaust manifold and the wall surface of the cylinder head where the exhaust outlet is formed. In the metal gasket, the bead substrate is formed with beads whose side is displaced along the parallel holes, and the bead region in the bead extending from the rising portion of the bead to the side of the hole is opposite to the protruding direction of the bead. A metal gasket for an exhaust manifold, wherein a stopper bead protruding in a direction and having a height less than a displacement height of the bead is formed.

The stopper bead is formed along the hole over the entire circumference or partially.

The bead substrate comprises a pair of bead substrates and an intermediate plate interposed between the bead substrates. The beads of the bead substrate are formed so as to extend in a direction in which the hole sides are spaced from each other. The stopper beads of the substrate respectively project toward the intermediate plate.

Alternatively, the bead substrate is a laminated bead substrate formed by laminating another bead substrate made of an elastic metal plate having beads formed along parallel holes, respectively. Each bead is formed so as to extend in a direction in which the hole sides are spaced from each other. Further, in the laminated bead substrate, the beads of the bead substrate having no stopper bead are laminated in contact with each other.

Further, the bead substrate has a heat-resistant non-metal layer serving as a lubricant coated on the surface in contact with the exhaust manifold or on the surface in contact with the exhaust manifold and the surface in contact with the cylinder head.

[0014]

The metal gasket for the exhaust manifold according to the present invention is constructed as described above and operates as follows. That is, this exhaust manifold metal gasket forms a bead whose hole side is displaced along the hole of the exhaust gas passage parallel to the bead substrate of the elastic metal plate, and the bead along the hole side from the rising portion is formed on the bead. Since a stopper bead protruding in the direction opposite to the protruding direction of the bead and having a height less than the displacement height of the bead is formed in the region, the bead has a half bead shape, but the stopper bead has a full bead shape. The spring rigidity of the stopper bead is increased, the bead can be prevented from being fully compressed, and the bead can be prevented from being settled or cracked at a high temperature. That is, in general, a metal gasket for an exhaust manifold has a high operating temperature due to exhaust gas, which causes a problem of settling of a bead.However, in this exhaust manifold metal gasket, a stopper bead is provided on the bead substrate to form a bead. Preventing full compression prevents bead settling.

Further, when the stopper beads are provided along the entire circumference of the hole, a stopper function is achieved and gas is prevented from entering the beads of the bead substrate.
It is possible to prevent the occurrence of settling and cracks in the bead, and further to reduce the dead space formed by the stopper bead between the bead substrate and its facing surface, thereby improving the sealing performance. You can

Alternatively, the exhaust manifold metal gasket is formed of a pair of the bead substrates and an intermediate plate interposed between the bead substrates into a laminated bead substrate, and the beads of the bead substrates are separated from each other on the hole side. In the case where the stopper beads of the bead board are projected toward the intermediate plate side, respectively,
The dead space formed by the stopper bead between the bead substrate and the intermediate plate can be further reduced, and the sealing performance can be improved. In addition, the stopper bead can function as a stopper to prevent gas from entering the bead of the bead substrate and prevent the bead from getting settled or cracked. Also,
By providing the stopper bead on the bead substrate, it is not necessary to use two intermediate plates, the number of layers in the entire metal gasket can be reduced, and the number of parts can be reduced.

The metal gasket for the exhaust manifold is
An intermediate plate is interposed between a pair of bead substrates each formed of an elastic metal plate having beads formed along the holes, and the intermediate plate faces at least one of the bead substrates in a region along at least the inner side of the bead. Since the stopper bead formed by the full bead protruding to a height less than the height of the bead is formed, the spring rigidity of the stopper bead is increased, and the bead of the bead substrate is prevented from being fully compressed and protected. When the stopper bead is formed over the entire circumference of the hole, the stopper bead fulfills the sealing function for the bead, and the durability of the bead is improved. It is possible to provide an inexpensive and highly reliable gasket that does not require a special space member and can reduce the number of parts. Further, the height of the stopper bead can be variously set according to the height of the bead, and the degree of prevention of total compression and the sealing property can be appropriately set.

Alternatively, in this exhaust manifold metal gasket, the stopper bead can be partially provided along the hole, and in that case, a bolt for fixing the flange portion of the exhaust manifold to the wall surface of the cylinder head. The position of the stopper bead may be determined in consideration of the position, the surface pressure can be appropriately adjusted, the compression state with respect to the bead can be appropriately adjusted, and the durability can be improved.

[0019]

Embodiments of the exhaust manifold metal gasket according to the present invention will be described below. In the drawings showing the respective embodiments described below, the reference numerals indicating parts and portions are given the same reference numerals for parts and portions having the same configuration and the same function, and duplicate explanations are omitted.

An embodiment of a metal gasket for an exhaust manifold according to the present invention will be described with reference to FIGS. 1 and 2.
FIG. 1 is a plan view showing a bead substrate of a metal gasket for an exhaust manifold according to the present invention, and FIG. 2 is an enlarged plan view of the metal gasket for an exhaust manifold of FIG. This exhaust manifold metal gasket is composed of a bead substrate 1 made of an elastic metal plate that is sandwiched and fixed between a wall surface of the cylinder head that opens an exhaust outlet and an end face of a mounting flange of the exhaust manifold. There is. This exhaust manifold metal gasket is shown in FIG.
Only one side of the mold engine is shown,
In addition, it can be applied to a multi-cylinder engine such as a 4-cylinder engine or an in-line 6-cylinder engine, and a plurality of exhaust gas passage holes 7 are formed in parallel. This exhaust manifold metal gasket is composed of one (FIG. 1) or a plurality (FIGS. 4 to 6) bead substrate 1 in which a plurality of holes 7 of an exhaust gas passage are formed in parallel. A plurality of bolt holes 8 are formed at intervals around the hole 7.

First, an embodiment of a metal gasket for an exhaust manifold according to the present invention will be described with reference to FIG.
FIG. 3 is an enlarged sectional view taken along the line AA in FIG. 2 showing an embodiment of the exhaust manifold metal gasket. The metal gasket for exhaust manifold of this embodiment is composed of one bead substrate 1 made of an elastic metal plate. The bead substrate 1 is provided with half-bead-shaped beads 4 each having a hole 7 side displaced along the hole 7. In the bead 4, projecting in the bead region along the hole 7 side from the rising portion 6 of the bead 4 in the direction opposite to the projecting direction of the bead 4,
A full bead-shaped stopper bead 5 having a height less than the displacement height of the bead 4 is formed. In this embodiment, FIG.
Further, as shown in FIG. 2, the stopper bead 5 is formed along the entire circumference of the hole 7. Stopper bead 5
Is a full bead, so the spring rigidity is set to be higher than the half bead of the bead 4. Therefore, it is possible to prevent the bead 4 from being completely compressed by the stopper bead 5,
The occurrence of cracks can be prevented.

In this exhaust manifold metal gasket, the stopper bead 5 provided on the bead substrate 1 can prevent the bead 4 from being fully compressed, so that the desired function can be achieved without using a high-grade elastic metal plate. You can Usually, the bead substrate 1 is made of ordinary steel, SUS430, S
US301H, high cost SUS305, ultra high cost Inconel 625, etc. are used.
Can be made to have a sufficient function even if it is made of ordinary steel, SUS430, or SUS301H.

Next, another embodiment of the exhaust manifold metal gasket according to the present invention will be described with reference to FIG. The exhaust manifold metal gasket of this embodiment is composed of a pair of bead substrates 1 and 2, and one bead substrate 1 is the same as that used in the above embodiment.
The other bead substrate 2 is made of an elastic metal plate having beads 4 formed along the parallel holes 7, and is made of a laminated bead substrate in which the bead substrate 1 and the bead substrate 2 are laminated. Each bead 4 of the bead substrate is formed so as to extend in the direction in which the holes 7 are separated from each other. In this embodiment, the stopper beads 5 formed on the bead substrate 1
Has a function of preventing the total compression of each bead 4 of the bead substrates 1 and 2.

Next, another embodiment of the exhaust manifold metal gasket according to the present invention will be described with reference to FIG. The exhaust manifold metal gasket of this embodiment is composed of a pair of bead substrates 1 and 1 and an intermediate plate 3 interposed between the bead substrates 1 and 1. The beads 4 and 4 of the bead substrates 1 and 1 are formed so as to extend in the directions in which the holes 7 are spaced from each other, and the stopper beads 5 and 5 of the bead substrates 1 and 1 project toward the intermediate plate 3 side. is there.

Another embodiment of the exhaust manifold metal gasket according to the present invention will now be described with reference to FIG. The exhaust manifold metal gasket of this embodiment is formed by laminating a pair of the laminated bead substrates of the embodiment shown in FIG. 4, and the beads 4 of the bead substrate 2 having no stopper bead are brought into contact with each other. It is laminated in a state.

As described above, the metal gasket for exhaust manifold according to the present invention uses the bead substrate 1 made of one elastic metal plate or the bead substrate 1 made of two or more elastic metal plates. It is composed of a gasket using a laminated bead substrate laminated in a bonded state or a gasket laminated in a non-fixed state with an intermediate plate interposed between a pair of bead substrates 1, and the number of bead substrates is desired. Although it is determined according to the height of the residual bead, in the present invention, the stopper bead 5 is provided on the bead substrate 1.
Since the number of bead substrates is smaller than that of the conventional gasket, it is possible to reduce the number of laminated layers.

Another embodiment of the exhaust manifold metal gasket according to the present invention will be described with reference to FIG. In the exhaust manifold metal gasket of this embodiment, the stopper beads 5A are not provided on the entire circumference along the hole 7, but are partially formed in plural. The stopper beads 5A are formed at four positions in relation to the bolt holes 8, in the middle between the bolt holes 8 in FIG. 7, so that the bead 4 is prevented from being fully compressed and the surface pressure is properly adjusted.

Next, still another embodiment of the metal gasket for exhaust manifold according to the present invention will be described with reference to FIG. In the exhaust manifold metal gasket of this embodiment, the stopper bead 5B is formed by a large number of projections along the entire circumference of the hole 7.

In this exhaust manifold metal gasket, the intermediate plate 3 is made of a softer metal than the bead substrates 1 and 2. For example, the bead substrates 1 and 2 are made of SUS30.
The intermediate plate 3, which is made of 1H and is an adjusting plate, is made of SECC (soft steel plate). In this exhaust manifold metal gasket, the thickness of the intermediate plate 3 is equal to that of the bead substrates 1 and 2.
The thickness of the bead substrates 1 and 2 can be formed to be, for example, 3 to 5 times thicker than the plate thickness of 0.2 to 0.
Formed to 3 mm, the thickness of the intermediate plate 3 is 0.5 to 0.8 mm
And the height of the beads 4 of the bead substrates 1 and 2 is 0.2.
The height of the stopper bead 5 can be set to 0 to 0.25 mm and the height of the stopper bead 5 to 0.04 to 0.15 mm.

By the way, the region in which the metal gasket for the exhaust manifold is arranged is usually, for example, 400 to 600 ° C.
And the temperature is high. Normally, the cylinder head is cooled with cooling water or the like, but the exhaust manifold is exposed to the exhaust gas, and the exhaust manifold becomes hotter than the cylinder head. Therefore, a difference in thermal expansion occurs due to the temperature difference between the wall surface of the cylinder head and the flange surface of the exhaust manifold, and drag occurs due to the flange surface of the exhaust manifold with respect to the wall surface of the cylinder head, and the metal gasket for the exhaust manifold is attached. It causes damage and impairs durability. Therefore, in order to prevent the drag phenomenon, the exhaust manifold metal gasket is made of heat-resistant molybdenum disulfide serving as a lubricant on the surface of the elastic metal plate forming the bead substrates 1 and 2, although not shown. The non-metal layer is coated to a thickness of, for example, about 10 to 50 μm to avoid a metal-to-metal contact state with the wall surface of the cylinder head and the flange surface of the exhaust manifold, and to provide a gasket with a lubricating function and seal. sex,
It is possible to ensure durability and strength. At this time, a surface of the bead substrates 1 and 2 in contact with the exhaust manifold, or a surface in contact with the exhaust manifold and a surface in contact with the cylinder head are coated with a non-metal layer. For example, only the upper surface of the bead substrate 1 in contact with the exhaust manifold, or the upper surface of the bead substrate 1 in contact with the exhaust manifold and the lower surface of the bead substrate 2 in contact with the wall surface of the cylinder head may be coated with heat-resistant molybdenum disulfide. it can. Also,
The non-metal layer coated on the surfaces of the bead substrates 1 and 2 can cover the irregularities even when the bead substrates 1 and 2 are machined, and can perform a sufficient sealing function.

[0031]

Since the exhaust manifold metal gasket according to the present invention is constructed as described above, it has the following effects. That is, since this exhaust manifold metal gasket is configured as described above, the conventional gasket has a high operating temperature due to the exhaust gas and causes bead sag, but it is formed on the bead substrate. By providing a stopper bead on the bead to prevent the bead from being fully compressed, the bead can be surely prevented from settling. Further, if the stopper beads are provided along the entire circumference of the hole, the dead space in the vicinity of the hole can be further reduced, the sealing property is improved, and the gas is prevented from entering the rising portion of the bead. It is possible to prevent the bead from getting settled or cracked due to corrosion caused by the above.

Further, if it is composed of a pair of bead substrates and an intermediate plate interposed therebetween, the complete compression of both bead substrates is prevented on both sides of one intermediate plate with which the beads of the two bead substrates abut. A compensating portion having a function of absorbing irregularity of the opposing mounting surface together with a sealing function for protecting the bead is formed, and the bead is prevented from being compressed due to overcompression of the bead, and the occurrence of cracks can be prevented, The stopper portion blocks the inflow of combustion gas to the bead side, protects the bead from corrosion due to high-temperature gas, and prevents the function of the bead from deteriorating.
That is, the annular portion of the stopper portion constitutes a compensating portion that prevents the bead from being completely compressed with respect to one of the bead substrates and that improves the sealing performance.

The metal gasket for the exhaust manifold is
One bead substrate with stopper beads or a pair of bead substrates with stopper beads and bead substrate without stopper beads without using a separate member such as a spacer or manufacturing it. substrate,
Alternatively, it can be configured only with a pair of the bead substrates and one of the intermediate plates, the number of parts can be reduced, the processing steps can be reduced, and the processing shape is simple, so that the manufacturing cost can be significantly reduced and the reliability can be improved. It is possible to provide a rich gasket. Further, since the bead substrate is provided with the stopper bead, it is not necessary to form a folded-back portion between the bead substrate and the intermediate plate, and a manufacturing process step of forming the folded-back portion is not required, and the folded-back portion is formed. Since it is not necessary to take measures against cracks, the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a plan view showing a bead substrate of a metal gasket for an exhaust manifold according to the present invention.

FIG. 2 is a partially enlarged plan view showing an embodiment of the exhaust manifold metal gasket of FIG.

FIG. 3 is an enlarged cross-sectional view taken along the line AA of FIG. 2 showing an example of the exhaust manifold metal gasket.

FIG. 4 is an enlarged sectional view of a region corresponding to line AA in FIG. 2 showing another embodiment of the exhaust manifold metal gasket.

5 is an enlarged sectional view of a region corresponding to line AA in FIG. 2 showing still another embodiment of the exhaust manifold metal gasket.

FIG. 6 is an enlarged cross-sectional view of a region corresponding to line AA in FIG. 2 showing another embodiment of the exhaust manifold metal gasket.

FIG. 7 is a partially enlarged plan view showing another embodiment of the metal gasket for exhaust manifold according to the present invention.

FIG. 8 is a partially enlarged plan view showing still another embodiment of the metal gasket for exhaust manifold according to the present invention.

[Explanation of symbols]

 1 bead substrate (with stopper bead) 2 bead substrate (without stopper bead) 3 intermediate plate 4 bead 5,5A, 5B stopper bead 6 rising part 7 hole 8 bolt hole

Claims (6)

[Claims] 1. A metal for an exhaust manifold comprising a bead substrate made of an elastic metal plate sandwiched and fixed between an end surface of a mounting flange of the exhaust manifold and a wall surface of the cylinder head having an opening for discharging an exhaust gas. In the gasket, the bead substrate is formed with beads whose side is displaced along the parallel holes, and in the bead region in the bead region along the hole side from the rising portion of the bead in a direction opposite to the projecting direction of the bead. A metal gasket for an exhaust manifold, characterized in that a stopper bead is formed that protrudes to the bottom and has a height less than the displacement height of the bead. 2. The metal gasket for an exhaust manifold according to claim 1, wherein the stopper bead is formed along the hole over the entire circumference or partially. 3. A pair of the bead substrates and an intermediate plate interposed between the bead substrates, wherein the beads of the bead substrate are formed so as to extend in a direction in which the hole sides are spaced from each other, and the bead is formed. 3. The exhaust manifold metal gasket according to claim 1, wherein the stopper beads of the substrate respectively project toward the intermediate plate. 4. The bead substrate comprises a laminated bead substrate in which another bead substrate made of an elastic metal plate having beads formed along parallel holes is laminated. The exhaust gasket metal gasket according to claim 1 or 2, wherein each bead is formed to extend in a direction in which the hole sides are spaced from each other. 5. The exhaust manifold metal gasket according to claim 4, wherein the laminated bead substrate is laminated such that the beads of the bead substrate having no stopper bead are in contact with each other. 6. The heat resistant non-metal layer as a lubricant is coated on the surface of the bead substrate that contacts the exhaust manifold, or the surface that contacts the exhaust manifold and the surface that contacts the cylinder head. Item 7. A metal gasket for exhaust manifold according to any one of items 1 to 5.