JP2002349346A - Bead substrate for metal gasket and metal gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bead substrate for a metal gasket, capable of maintaining its sealing performance for a long period of time, without having a coating material removed or diminished even in the vicinity of a cylinder bore, and a metal gasket. SOLUTION: On the front surface of the bead substrate 2, a coating layer is provided all over the surface. For the coating layer, regarding a concave portion of a bead 4 as a boundary 9, a heat-resistant coating material 7 is provided on the side of the cylinder bore 3, and a normal coating material 8 is provided on the side opposite to the cylinder bore 3. Even if the material composing a binder is diminished due to a high surface pressure and an intense heat during the operation over a long period of time, solid powder having a high-temperature heat resistance is left. Therefore, the performance the coating material is required to have, such as to protect the surface of the bead substrate and to provide conformability (micro sealing performance) to the surfaces of a cylinder head and a cylinder block, is never deteriorated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal gasket used for sealing an internal combustion engine such as an automobile engine and a bead plate for the metal gasket.

[0002]

2. Description of the Related Art For example, a metal gasket is generally used as a sealing means for sealing between a cylinder head and a cylinder block of an automobile engine. These metal gaskets have a single-layer structure using only one bead plate having a bead forming a seal portion, or a multi-layer structure obtained by combining this bead plate with another sub-plate (a folded plate, an adjustment plate, etc.). Various types such as those having a structure have been put to practical use.

[0003] In these gaskets, a coating layer is provided on the surface of a bead plate or the surface of a sub plate in order to further improve the sealing performance between a cylinder head and a cylinder block. A typical example is shown in FIG.

[0004] In FIG. 4, (a) shows a metal gasket 2.
FIG. 1B is a plan view of FIG. 1 as viewed from the front side, and FIG.
FIG. 3C is a cross-sectional view, and FIG. 3C is a DD cross-sectional view. In addition,
(A) simplifies the actual metal gasket and shows only those parts relevant to the present invention, and (b) and (c) also show the dimensions (a) and the actual metal gasket for convenience of explanation. Not compatible with gaskets. Therefore, these drawings are only schematic diagrams. The same applies to not only FIG. 4 but also all the drawings attached to this specification.

The bead plate 22 of the metal gasket 21 has:
The cylinder holes 23 are provided by the number of cylinders of the engine, and beads 24 forming a seal portion are provided so as to surround the cylinder holes 23. And metal gasket 2
Bolt holes 25 for fixing the cylinder 1 between the cylinder head and the cylinder block, and water holes and oil holes 2 for passing cooling water.
9 are provided.

[0006] As shown in FIG.
It has a structure in which a folded plate 26 is sandwiched between two bead plates 22. The folded plate 26 has a plane shape substantially similar to that shown in (a) and has a cylinder hole, a bolt hole, a water hole and an oil hole, but has no bead and instead surrounds the cylinder hole. The portion has a folded portion 26a.

[0007] The folded plate 26 is made of a metal gasket 2.
When 1 is mounted between the cylinder head and the cylinder block and tightened with bolts, the folded portion 26a comes into contact with the bead plate 22 to perform primary sealing of gas from the cylinder hole and to prevent the bead 24 from being excessively large. It has a role to prevent any deformation.

The front side of the bead plate 22 (hereinafter referred to as bead plate 2)
2, the side where the bead 24 forms the concave portion is the surface side,
The side on which the projection is formed will be referred to as the back side. )
In order to further improve the sealing performance between the cylinder head and the cylinder block, a coating layer 27 is selectively provided on the entire surface or on a portion required for sealing. Although not shown, a coating layer may be formed on the interlayer surface such as the back surface of the bead plate or the surface of the folded plate as necessary. As a coating material for forming the coating layer 27, an elastic member such as NBR rubber or fluorine rubber is used.

[0009]

However, such a conventional metal gasket having a coating layer has the following problems. That is, a strong surface pressure acts on a portion of the bead plate 22 that comes into contact with the folded portion 26a of the folded plate 26, and furthermore, high heat is received from the cylinder portion, so that the coating material peels or disappears during operation of the engine. This can result in inadequate sealing. In a single-layer metal gasket using only one bead plate 22 and a multi-layer metal gasket in which a beat plate 22 and a flat adjustment plate for adjusting the thickness are stacked, the bead is closer to the cylinder hole than the bead. The situation where the part is subjected to high surface pressure and high heat is the same, and there was a similar problem.

[0010] The present invention has been made in view of such circumstances, and even in a portion close to a cylinder hole, a coating material does not peel or disappear, and a metal that can maintain a sealing property for a long period of time. It is an object to provide a gasket bead plate and a metal gasket.

[0011]

A first means for solving the above problems is a bead plate used for a metal gasket for an internal combustion engine, wherein a bead is formed so as to surround a cylinder hole. A coating material formed by powder-coating a solid powder having high-temperature heat resistance on the cylinder hole side, on the surface where the bead forms the concave portion, with the concave portion of the bead as a boundary, A bead plate for a metal gasket is characterized in that a rubber-based or resin-based coating material is coated on the side opposite to the hole.

In this means, on the surface on which the bead forms the concave portion, that is, on the front surface side, the cylinder hole side is formed by powder coating a solid powder having high temperature resistance with the concave portion of the bead as a boundary. The coating material is coated. Having “high-temperature heat resistance” means that it does not deform or change its properties due to high heat from the cylinder part.

[0013] By doing so, the high temperature heat resistant solid powder is coated on the cylinder hole side where the temperature is high, so that the surface of the bead plate can be protected or the surface of the cylinder head or cylinder block can be protected. The performance required for the coating material such as imparting conformability (micro sealing property) is not deteriorated. Therefore, good sealing properties can be maintained over a long period of time.

Further, a rubber-based or resin-based coating material is coated on the side opposite to the hole of the cylinder with respect to the concave portion of the bead. This is because oil and water flow holes are provided in this portion, and these conventionally used coating materials are more excellent in sealing performance.

Further, a feature of the present means is that a boundary between these two types of coating materials is provided in the concave portion of the bead. At the boundary between the coating materials, the coating materials may overlap with each other to increase the thickness. If there is such a portion, the surface pressure is concentrated on the portion, and the surface pressure around the portion is reduced, which causes a problem. However, in the present means, since this boundary is provided in the concave portion of the bead, even if the coating materials overlap with each other to increase the thickness, the unevenness of the surface pressure as described above is thereby prevented. Does not occur.

Conversely, a break in the coating material may occur at the boundary between the coating materials. When such a phenomenon occurs, the sealing performance is reduced. However, in this means, this boundary is provided in the recess of the bead.
In this case, since the sealing property is ensured at both ends of the bead, the sealing property does not decrease even if there is a cut.

The surface (back surface) opposite to the surface on which these coatings are applied may or may not be applied. When a coating is applied, a conventional coating material is applied over the entire surface. Alternatively, a portion close to the cylinder hole may be formed of a coating material obtained by solidifying the above-described solid powder having high temperature resistance with a binder, and a portion far from the cylinder hole may be formed of a rubber or resin coating material. And the boundary may be provided in the convex part of a bead.

A second means for solving the above-mentioned problem is as follows.
A bead plate used for a metal gasket for an internal combustion engine, in which a bead is formed so as to surround a cylinder hole, and the bead is formed on a surface on which a concave portion is formed, with the concave portion of the bead as a boundary. The cylinder hole side is coated with a coating material obtained by solidifying solid powder having high temperature resistance with a binder, and the opposite side of the cylinder hole is coated with a rubber-based or resin-based coating material. A bead plate for a metal gasket (claim 2).

In this means, instead of the "coating material formed by powder coating solid powder" in the first means, a coating material obtained by solidifying solid powder having high temperature resistance with a binder is used. are doing. Therefore, when performing the coating, the solid powder can be evenly adhered to the bead plate, and the material constituting the binder during long-term operation, even if it is lost due to high surface pressure and high heat Since solid powder having high temperature heat resistance remains,
The performance required for the coating material, such as protecting the surface of the bead plate and imparting conformity (micro-sealability) with the surface of the cylinder head or cylinder block, does not deteriorate. Therefore, good sealing properties can be maintained over a long period of time. Other functions and effects are the same as those of the first means.

A third means for solving the above-mentioned problem is as follows.
A metal gasket having a bead plate for a metal gasket as the first means or the second means (Claim 3).

In this means, since the metal gasket bead plate as the first means is provided, the first
The same operation and effect as described in the means are provided. In this case, having a bead plate includes not only a metal gasket combined with another substrate such as the folded plate or the adjustment plate, but also a case where the bead plate is used alone as a metal gasket.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an outline of a metal gasket which is an example of an embodiment of the present invention. FIG. 1A is a plan view of the metal gasket 1 as viewed from the surface side, FIG.
(C) is BB sectional drawing.

The bead plate 2 of the metal gasket 1 is provided with the same number of cylinder holes 3 as the number of cylinders of the engine, and a bead 4 forming a seal so as to surround it.
Is provided. A plurality of bolt holes 5 for fixing the metal gasket 1 between the cylinder head and the cylinder block, and a plurality of water holes and oil holes 10 for passing cooling water are provided.

The cross section taken along the line AA has a structure as shown in FIG. 2B, in which a folded plate 6 is sandwiched between two bead plates 2. The folded plate 6
It has a substantially planar shape similar to that shown in (a), has a cylinder hole and a bolt hole, but does not have a bead, and instead has a folded portion 6a in a portion surrounding the cylinder hole.

The metal plate 1 is attached between the cylinder head and the cylinder block.
When tightened with bolts, the folded portion 6a comes into contact with the bead plate 2 to perform primary sealing of gas from the cylinder hole and to prevent the bead 4 from being excessively deformed.

On the surface side of the bead plate 2, a coating layer is provided at a place where a coating layer is required in order to further improve the sealing property between the cylinder head and the cylinder block. In the coating layer, with the concave portion of the bead 4 as the boundary 9,
The material provided on the cylinder hole 3 side is a heat-resistant coating material 7
The material provided on the side opposite to the cylinder hole 3 is usually the coating material 8.

In this embodiment, as the heat-resistant coating material 7, a material obtained by solidifying solid powder having high-temperature heat resistance with a binder is used, but a material obtained by performing powder coating without using a binder may be used. . As a solid powder having high temperature heat resistance, since Al powder has a certain degree of plasticity,
Although preferable in terms of conformability with the cylinder head and the cylinder block, other metal powders and ceramic powders such as alumina can also be used.

As the binder, it is appropriate to use various rubbers or various resins such as silicone resin and epoxy resin, but it has a certain degree of heat resistance in order to withstand high temperatures from the cylinder chamber. It is necessary.

As the coating material 8, an elastic member such as NBR rubber or fluorine rubber can be used as in the conventional case.

FIG. 2 shows another example of a method of providing a coating material. 2A, 2B, and 2C are cross-sectional views taken along the line BB of FIG. 1, and correspond to FIG. FIG.
As shown in (a), the heat-resistant coating material 7 and the normal coating material 8
The boundary 9 is not necessarily provided at the center as long as the boundary 9 is provided in the concave portion of the bead 4.

A gap 11 may be provided between the heat-resistant coating material 7 and the normal coating material 8 as shown in FIG.
Further, as shown in (c), if the heat-resistant coating material 7 and the normal coating material 8 are in the concave portion of the bead 4, their ends may overlap each other to form an overlapping portion 12. It is (b) that contributes to the seal at the bead 4 portion.
As shown by E, the end of the bead 4 and the concave portion of the bead do not contribute to the seal.
Even if there is 1 or the overlapping portion 12, the sealing property does not deteriorate.

In the case where a usual coating material is used up to the vicinity of the cylinder hole as in the prior art, if the coating material at the bead end E on the cylinder hole side and the flat portion inside the bead disappears, the corresponding material is lost. Although the surface pressure of the part decreases and the spring constant of the bead decreases, the amplitude increases, and the stress fluctuation at the bead end E may increase, which may lead to the occurrence of cracks. Since the conductive powder coat layer is prevented from disappearing, the initial amplitude is maintained and cracks are less likely to occur.

In the above embodiment, a bead is formed individually for each cylinder.
The present invention can also be applied to a device in which the distance between the cylinder holes is narrow and the beads overlap between the cylinder holes to form one common bead.

FIG. 3 shows this example. In FIG.
(A) shows the relationship between the cylinder hole 3 and the bead 4, and as shown in the figure, the bead 4 overlaps between the cylinder holes 3 to be one. An enlarged portion surrounded by a circle is shown in FIG. The beads 4 overlap between the cylinder holes 3 to form a common bead 13. (C) is an enlarged view of a section XX of (a) of the common bead 13;
Shown in

In this case, since both ends of the common bead 13 face the cylinder hole 3, (b)
As shown in (c), the coating material on both side end surfaces of the common bead 13 becomes the heat-resistant coating material 7. At this time, a normal coating material may be applied in the concave portion of the common bead 13, but since the temperature between the cylinder holes 3 is particularly high, the common bead 13 is not applied with the normal coat, and the normal coat is applied. , (B), it is preferable to limit the distance to the meeting portion where the beads 4 start to overlap.

As described above, in the present invention, when both sides of the bead are formed with the cylinder holes, the part includes a heat-resistant coating on both sides of the bead.

[0037]

As described above, in the present invention, even in a portion near the cylinder hole, the coating material does not peel or disappear, and the sealing property can be maintained for a long period of time.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of a metal gasket which is an example of an embodiment of the present invention.

FIG. 2 is a diagram showing another example of a method of providing a coating material.

FIG. 3 is a diagram showing an example in which the present invention is applied to a portion having a common bead.

FIG. 4 is a view showing an example of a conventional metal gasket.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Metal gasket 2 ... Bead plate 3 ... Cylinder hole 4 ... Bead 5 ... Bolt hole 6 ... Folded plate 6a ... Folded part 7 ... Heat resistant coating material 8 ... Normal coating material 9 ... Boundary 10 ... Water hole, oil hole 11 ... Gap 12 ... overlapping part

Claims (3)

[Claims] 1. A bead plate used for a metal gasket for an internal combustion engine, wherein a bead is formed so as to surround a cylinder hole, and a bead recess is formed on a surface where the bead forms a recess. As a boundary, a coating material formed by powder coating a solid powder having high temperature resistance on the cylinder hole side, and a rubber-based or resin-based coating material on the opposite side of the cylinder hole, respectively. A bead plate for a metal gasket, which is coated. 2. A bead plate used for a metal gasket for an internal combustion engine, wherein a bead is formed so as to surround a cylinder hole, and a bead recess is formed on a surface of the bead forming a recess. At the boundary, the cylinder hole side is coated with a coating material obtained by solidifying solid powder having high temperature resistance with a binder, and the other side of the cylinder hole is coated with a rubber or resin coating material. A bead plate for a metal gasket, comprising: 3. A metal gasket comprising the metal gasket bead plate according to claim 1.