JP3668355B2 - Metal gasket - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a metal gasket, and more particularly to a metal gasket having a bead.
[0002]
[Prior art]
As is well known, with the recent improvement in performance in internal combustion engines, the requirements for gaskets have become more severe, and there is a demand for gaskets that can achieve gas sealing performance against higher internal pressures with a thinner thickness.
[0003]
In response to such demands, a metal sheet is used and a grommet or shim is welded to the periphery of the opening, a bead is formed, or an elastic seal member is attached to open a seal line with a higher surface pressure. Metal gaskets have been proposed that are intended to ensure gas sealing properties by being provided at the periphery.
[0004]
However, with a metal gasket welded with grommets, a seal line can be provided only at a specific part such as the periphery of the opening, and when the flange surface is narrow, the seal width is insufficient and the grommets can be applied. Further, since the step amount is determined by the thickness of the grommet, the step amount is always constant and cannot be made smaller than a certain value. On the other hand, a metal gasket formed with a bead has an advantage that it can be formed to a thinner thickness. However, since the generated surface pressure is mainly determined by the size and shape of the bead, it is easy to prevent seal leakage due to bead sag. It was something that would occur. In addition, since it is difficult to control the compression amount of the elastic seal member with a metal gasket to which an elastic seal member is attached, the application amount and application shape of the elastic seal member must be redesigned for each gasket. Not only is it complicated, but there is a lack of durability due to large changes over time, and the gas sealability tends to be lost due to peeling due to mechanical vibration or the like.
[0005]
Furthermore, metal gaskets have been proposed that attempt to improve the fatigue resistance of the bead by attaching an elastic seal member to the bead, but the surface pressure on the convex surface side of the bead is ensured, but on the concave surface side of the bead. The tightening load is distributed at three locations, that is, the elastic seal member portion and the bead rising portion, so that a sufficient seal surface pressure cannot be secured.
[0006]
[Problems to be solved by the invention]
The present invention has the advantage of a metal gasket that can achieve gas sealing performance with a thin thickness against high internal pressure, and has excellent durability by improving the fatigue resistance of the bead and smaller tightening. It is intended to provide a metal gasket with mass productivity that can minimize the deformation of the flange surface during installation by being able to reliably cope with higher internal pressure with the applied force, and can be manufactured at a lower cost. It is.
[0007]
[Means for Solving the Problems]
The metal gasket according to the present invention is formed of at least one metal thin plate having a bead, and a stepped member made of a coating layer having high load resistance is provided on the bead. The stepping member is attached to at least the top region on the convex side of the bead.
[0008]
Thus, the metal gasket of the present invention, the bead by a load tightening with concentrated in disposed position of the step with members ensuring the sealing surface pressure, to reduce the stress amplitude of the bead completely compress the bead The fatigue resistance of the bead is improved by reducing the load stress on the bead. Further, the stepped member attached to the top region on the convex surface side of the bead reduces the stress amplitude of the bead to improve fatigue resistance, and the surface pressure on the convex surface of the bead is secured by the stepped member, and the concave surface The surface pressure on the side is secured by the reaction force of the fully compressed bead.
[ 0009 ]
Metarugasuke' bets invention also together can also be attached respectively a step with member into a top region and a concave side of the thick region of the convex side of the bead, thereby improving the fatigue resistance of the bead, the bead The surface pressure on the convex surface and the concave surface is secured.
[ 0010 ]
Furthermore, in the metal gasket of the present invention, the stepped member is formed of at least one selected from the group consisting of synthetic resin, inorganic substance and metal powder, or a composite material mainly composed of at least one selected from the group. You can also. As a result, the stepped member is reliably provided in a predetermined pattern with a predetermined thickness by a conventional printing means, metal spraying means, or dispenser, so that mass productivity is improved and manufacturing cost is further reduced. It is possible.
[ 0011 ]
Furthermore, the metal gasket of the present invention can be coated with a rubber coating on the surface of the stepped member, thereby further ensuring the gas sealing performance between the flange surface to be applied.
[ 0012 ]
Furthermore, the gasket of the present invention can make the thickness of the rubber coating thinner than the thickness of the stepped member, so that its elasticity can increase or regulate the compression amount of the bead by the stepped member. There is no adverse effect.
[ 0013 ]
DETAILED DESCRIPTION OF THE INVENTION
[ 0014 ]
The metal gasket according to the embodiment of the present invention has a predetermined opening such as a bore hole 2a, an oil hole 2b, a bolt hole 2c, etc. in a single metal thin plate 1, as shown in FIG. Is formed. Beads 3a surrounding the openings are formed at the peripheral edges of these openings, and similar beads 3b are also formed at other portions that require an increase in surface pressure.
[ 0015 ]
The required bead 3a or 3b (all beads if necessary) is provided with a stepped member 4 made of a coating layer having a high load resistance.
[ 0016 ]
As shown in FIG. 2, the stepped member 4 is provided in the top region D (see FIG. 3) on the convex surface side of the bead 3 a (or 3 b), and is thereby mounted between the flange surfaces F and F. At this time, as shown in FIG. 4, the bead can be completely compressed to reduce the stress amplitude, and at the same time, the reaction force of the bead can be maximized to generate a larger surface pressure. As shown in FIG. 3, the “top region” is between the transition starting points C where the transition from the top A of the bead to the inclined portion B starts, and is selected according to the required surface pressure from the surface Sa of the top A. Means a region D defined between the boundary surface Sb separated by the thickness Ta of the stepped member and the convex surface of the bead.
[ 0017 ]
At this time, since the stepped member 4 is provided in the top region D, the stepped member 4 does not hinder the deformation at both end portions of the inclined portion B (see FIG. 3) of the bead that generates surface pressure during compression. In addition, there is no influence on the generated stress of the bead, and the load on the stepped member 4 due to the deformation of the bead can be minimized.
[ 0018 ]
As long as the coating layer forming the stepped member 4 can have high load resistance, any member can be applied, but it can be reliably provided with a predetermined thickness and a predetermined pattern and is mass-productive. In order to ensure, at least one selected from the group of synthetic resins, inorganic substances and metal powders, or a composite material mainly composed of at least one selected from the group, known printing means and metal spraying It is desirable to adhere by means or a dispenser.
[ 0019 ]
Epoxy resin, polyamide, polyimide, etc. can be used as a synthetic resin suitable for forming a coating layer by printing means or a dispenser, glass fiber, glass powder, ceramic powder, etc. can be used as an inorganic substance, and metal powder as Stainless tip, aluminum powder, etc. can be used. Moreover, steel, aluminum, copper, etc. can be used as a metal suitable for metal spraying.
[ 0020 ]
Figure 5 is a view showing a metal gasket according to another embodiment of the present onset bright, top region D of the convex side of the bead 3 and the concave side of the thick region E (see FIG. 3) and in step with members 4a and 4b are The configuration is the same as that of the above-described embodiment except that each is different. Step with member 4b is provided as a "thickness region", as shown in FIG. 3, separated by a thickness T b of the step with members that are selected depending on the required surface pressure from the rear surface S c of the top A It means the region E defined by the boundary surface Sd and the concave surface of the bead. Here, in the case of a trapezoidal bead as shown in the figure, the stepped member 4b has at least a portion where the distance from the back surface S c (see FIG. 3) at the top of the bead is maximum beside the thickness region E. Thus, it should be attached so as to be positioned between the transition start points C so that the tightening load is not applied to the inclined portion B of the bead and the deformation is not hindered.
[ 0021 ]
Flange surface F, when mounted between F, step with members 4b and, at the same time act to regulate the amount of compression of the bead 3 to relieve the applied stress on the bead, the step with member 4b is bead concave This is the concentration point of the tightening load on the side. On the other hand, the stepped member 4a, like the stepped member in the embodiment described with reference to FIGS. 2 and 4, compresses the bead to reduce the stress amplitude, and at the same time, draws a larger reaction force of the bead. However, the stepped member 4b is not completely compressed. Therefore, the bead in the present embodiment can achieve the improvement of the fatigue resistance of the bead and the generation of the surface pressure at a higher level than the bead in the above-described embodiment. In addition, the stepped members 4a and 4b can be manufactured with a more durable and more durable metal gasket by changing the thickness thereof relative to the required surface pressure distribution.
[ 0022 ]
FIG. 6 is a view showing a metal gasket according to still another embodiment of the present invention, which is the same as the above-described embodiments except that the rubber coating 5 is coated on the surface of the stepped member 4. Composed. In the case of illustration, the form shown in FIG. 2 is taken as an example, but it will be easily understood that the present invention can be similarly applied to other forms described above.
[ 0023 ]
Since the rubber coating 5 is elastically interposed between the stepped member 4 and the flange surface F, the gas sealing property can be further ensured. However, the rubber coating 5 is applied with a thickness that is sufficiently thin relative to the thickness of the stepping member 4 so that the elasticity does not adversely affect the increase or restriction of the bead compression amount by the stepping member 4. Should be. Examples of the member applicable as the rubber coating 5 include NBR, fluorine rubber, and silicon rubber.
[ 0024 ]
In each of the above-described embodiments, the bead has been described as a full bead shape having a trapezoidal shape. However, a stepped member or a rubber coating is similarly applied and used even in other shapes such as a semicircular shape or a mountain shape. It is possible.
[ 0025 ]
【The invention's effect】
As described above, according to the present invention, by providing the bead with the stepped member made of the coating layer having a high load resistance, the tightening load is concentrated on the portion where the stepped member is disposed, and the sealing surface. It is possible to reduce the stress applied to the bead and improve the fatigue resistance of the bead by ensuring the pressure and reducing the bead stress amplitude by completely compressing the bead or regulating the amount of bead compression. it can. In addition, by attaching a stepping member to the top region on the convex surface side of the bead so as to increase the compression amount of the bead, the stress amplitude of the bead is reduced to improve fatigue resistance, and the surface pressure on the convex surface of the bead is also improved. Can be secured by the stepping member, and the surface pressure on the concave surface side can be secured by the reaction force of the fully compressed bead.
Further, by attaching each step with member into a top region and a concave side thickness region of the convex side of the bead, at the same time the fatigue resistance of the bead to more effectively improved, the surface of the convex and concave of the bead Pressure can be secured.
[ 0026 ]
In addition, by forming the stepped member with at least one selected from the group of synthetic resins, inorganic substances and metal powders, or a composite material containing at least one selected from the group as a main component, conventional printing means In addition, the stepped member can be reliably provided in a predetermined pattern with a predetermined thickness by a metal spraying means or a dispenser, so that mass productivity can be improved and the manufacturing cost can be further reduced. Furthermore, by covering the surface of the stepping member with a thin rubber coating, the gas sealability between the flange surface and the flange surface can be further ensured without adversely affecting the increase in the amount of compression of the bead by the stepping member or the regulation. Can be secured.
[Brief description of the drawings]
FIG. 1 is a partial plan view showing an example of a metal gasket according to an embodiment of the present invention.
FIG. 2 is a schematic enlarged sectional view taken along line II-II in FIG.
FIG. 3 is a schematic cross-sectional view for explaining a “top region” and a “thickness region”.
4 is a schematic enlarged cross-sectional view showing a state where the bead shown in FIG. 2 is mounted between flange surfaces. FIG.
FIG. 5 is a schematic cross-sectional view similar to FIG. 2, showing a metal gasket according to another embodiment of the present invention.
FIG. 6 is a schematic cross-sectional view similar to FIG. 2, showing a metal gasket according to still another embodiment of the present invention.
[Explanation of symbols]
1 Metal sheet
3, 3a, 3b bead
4, 4a, 4b Stepping member
5 Rubber coating
D Top region
E Thickness area

Claims (5)

The bead is formed of at least one thin metal plate, and the bead is provided with a stepped member made of a coating layer having high load resistance, and the stepped member is attached to at least the top region on the convex surface side of the bead. metal gasket, characterized in that that.   2. The metal gasket according to claim 1, wherein the stepped member is attached to a top region on the convex surface side and a thickness region on the concave surface side of the bead. According to claim 1 or 2 wherein the step with member is characterized in that it consists of a composite material according to at least one or at least one principal component which is selected from said group which is selected from the group of synthetic resins, inorganic substances and metal powder Metal gasket as described in The metal gasket according to claim 3, wherein a rubber coating is coated on a surface of the stepped member. The metal gasket according to claim 4, wherein a thickness of the rubber coating is thinner than a thickness of the stepped member.

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