JPS623340B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an embossed gasket with increased strength to resist flattening under the action of compressive forces, thereby improving sealing properties.

Gaskets are widely used to form a seal between a pair of opposing surfaces, such as between an engine block and a head in an internal combustion engine. Gaskets used in this manner provide seals between a relatively large number of interconnected cavities for the flow of different types of fluids and under different pressures.
It is necessary to prevent the fluids from mixing or leaking to the outside. Such gaskets most often have a metal body in combination and may include one or more sealing embossings. These embossings are protrusions formed on the body of the gasket that reduce the contact area between the gasket and its opposing surface, increasing the compressive force per unit area, thereby creating a more effective seal. It will be done. U.S. Pat. No. 3,352,564 to Jonsson discloses a gasket having typical embossing, which is formed by deforming a metal body, such as around a cylinder bore, thereby forming a gasket around the body. Displaced above and below the metal surface. Embosses produced in this manner include a ridge or protrusion with a corresponding depression or depression formed on the opposite side of the protrusion.

One of the problems encountered with these typical embossed gaskets shown in the Johnson patent is that the embossments flatten under compressive forces. If this occurs, the load intended to be concentrated in the area of the embossing will be distributed over a much wider area of the gasket, reducing the effectiveness of the seal.

In accordance with the present invention, an embossed gasket is provided for forming a seal between a pair of opposing surfaces. The gasket includes a body having a pair of spaced apart major surfaces and having at least one aperture formed therein. At least one embossing is formed on the body of the gasket. The embossment includes at least one protrusion projecting outwardly from one major surface and a corresponding recess or depression recessed inwardly from the other major surface. The gasket, and particularly the embossed portion of the gasket, is disposed between and compressed into sealing engagement with a pair of opposing surfaces. A filler material, such as a sealant, is placed within the recess or recess of the embossment, and when the embossment is compressed between a pair of opposing surfaces, the sealant prevents the embossment from flattening and losing much of its intended sealing effect. This improves sealing properties.

By preventing the embossing from flattening, the compressive force between the pair of opposing surfaces is concentrated over the area of the embossing, i.e., on the surface of the upper surface of the protrusion and the area near the periphery of the recess. Ru. Thus, by providing a filler member within the recess of the emboss, the emboss is prevented from flattening and the gasket forms a more effective seal between the surfaces to be sealed, such as between the cylinder block and the head.

Referring first to FIGS. 1 and 2, a typical gasket assembly 1 embodying the basics of the invention is shown.
0, the assembly 10 includes a first upper gasket surface 14 and a second lower gasket surface 16.
a main body or body 12 of the gasket having
including. Gasket body 12 is approximately 0.508mm
(0.020in) thick steel plate. However, the gasket body may be made of other materials and constructions depending on the use in which the gasket assembly is installed, typically those described in U.S. Pat. Nos. 3,565,449 and 3,108,818. be. Gasket body 1
2 is formed with a plurality of positioned apertures, including a main aperture and apertures such as bolt holes. In gasket assembly 10, in a gasket assembly intended for use as an intake manifold gasket, gasket body 1
2 is a main opening 20 and a small opening 22 which becomes a bolt hole.
including.

Gasket body 12 has continuous embossing 30
is formed and this embossment 30 is spaced from the main opening 20 as the preferred embossment of the present invention is shown in FIG. The gasket body 12 also has a continuous embossing 3 spaced from the outer edge of the gasket.
1 is formed. These embossings are formed in a known manner by pressing into a flat sheet metal plate or other material from which the body 12 is made. These sealing embossments vary in depth and size depending on the usage situation in which the gasket is installed.

As best shown in Figure 2, Emboss 3
0 has a protrusion or protrusion 32 projecting outwardly from the main surface 14 and a corresponding recess or recess 34 recessed inwardly or upwardly from the main surface 16. The embossing 31 has a similar structure.

According to the invention, a filler or filler member 36, preferably a sealant such as a resilient elastomeric material, is disposed within this recess 34. A particularly suitable filler for use as a filler is a silicone elastomer such as that sold by Dow Corning under the tradename Sylgard 187. Sylgard 187 is available as a two-component injection system and is generally described as a concentrated product of linear fluid organopolycyclosanes containing terminal hydroxyl groups with alkyl silicate esters. Typically, catalysts containing metal salts of monocarboxylic acids are used to accelerate the curing of this system.

In the embodiment shown in FIG. 2, the filler member or sealant 36 substantially fills the recess and the free or outer surface 38 of the sealant 36.
is located at a position slightly recessed from the main surface 16. In other embodiments, side 3 of sealant 36
8 is generally coplanar with the major surface 16 of the gasket body 12, and in other embodiments, the outer surface 38 of the sealant 36 is generally coplanar with the major surface 16 of the gasket body 12, depending on the material used as the filler member and the sealing characteristics desired. It can be projected outwardly beyond the main surface 16. Generally, the location of the outer surface 38 of the filler member 36 is such that the filler member does not rupture, become excessively extruded, or otherwise protrude beyond a certain point when the gasket is subjected to compression. It won't happen.

Figure 3 shows that the gasket in Figure 1 is connected to a pair of opposing surfaces 4.
0 and 42, showing a state of sealing engagement. As shown, the embossing 30 as shown in FIG. 2 has been compressed until the filler member 36 abuts opposing portions of the surface 42. This compressive load is then distributed across the entire width of the bead or embossment, but the sealing action in the area of the embossment is concentrated. If the filler material is a sealant, such as a silicone rubber, it will tend to flow sufficiently to fill imperfections in the opposing surfaces or gasket body surfaces to be sealed and to prevent leakage through those imperfections. .

In prior art embossed gaskets, compressive loads tend to concentrate at points P _P and P _E , etc., which are the top center position of the protrusion and the position of the periphery of the recess on the other side of the gasket, respectively. . When this load is applied, the bead or projection flattens. This is because there is almost point contact at these points. For this reason, in many cases the load is substantially distributed over the entire surface of the loaded gasket body instead of being concentrated on the beads or protrusions as intended, leaving the gasket unable to provide an effective seal or It was not maintained. Leakage often occurs as a result of ineffective load concentration at the embossing and is due to scratches or other imperfections in the embossing or mating surfaces. Moreover, once the embossing is actually immersed, there is essentially no recovery in the sealing area, which becomes apparent when the embossed gasket, especially the embossed metal gasket, is removed from the point of use. A lack of recovery capacity is a lack of elasticity and therefore a true lack of sealing effectiveness.

On the other hand, the embossing provided with the filling member according to the present invention has a substantially sufficient recovery ability by removing the gasket from its point of use, and the embossing remains in an embossed rather than flat state. can. Additionally, the sealing effect of the embossment spans the area of the protrusion and is effectively concentrated at the embossment, rather than being dissipated throughout the gasket body, as is often the case with conventional embossed gaskets. That becomes clear. Furthermore, by having a filling member such as an elastomer, embossing,
Defects in the embossed or sealing surfaces are easily tolerated and leaks that sometimes occur with conventional embossed gaskets are prevented.

As previously mentioned, the embossing is preferably formed by permanently modifying the body of the gasket. In Figures 2 and 3, the gasket body is sheet metal. In the embodiment shown in FIGS. 2A and 3A, the gasket body 112 is provided with a layer 11 of rubber-bonded asbestos sheet material on each side.
The core 114 comprises a laminated thin metal sheet or core 114 having a layer 116 of laminated thin rubber-bonded asbestos sheet material having a thickness of 6. The embossing 130 has a protrusion 132 projecting upward from the first main surface 118 and a corresponding protrusion 132 on the other main surface 12.
0 and a recessed portion 134 projecting inwardly from the bottom. Filling member 136 such as silicone elastomer
substantially fills the recess. This is slightly recessed inward from surface 120. Gasket 112 is used in similar situations to gasket 12 and obtains similar improved performance characteristics.

A suitable method for securing a sealant or filler member within an embossed cavity or recess is described in U.S. Pat.
Described in No. 3477867. In general, the Hillier patent describes a screen printing process in which a curable liquid sealant material is printed onto an area relatively closely surrounding the opening of the gasket. This method can be used in the present invention by silk screening the sealant directly into the recesses or depressions of the embossing.

As previously mentioned, the silicone filling member can be recessed, coplanar, or protruded from the major surface on which the embossed recess is formed. The gasket in the preferred embodiment is intended for use under high temperature conditions and it is preferred to use a high temperature resistant silicone elastomer, although its extrusion resistance is inferior compared to other materials such as nitrile epoxies. This shape of embossing tends to protect the silicone against extrusion and
It is possible to use silicones that have a strong tendency to extrude at high temperatures, such that the use of nitrile epoxies is preferred. However, filler materials other than silicones may be used where temperature is not an issue, and filler materials other than elastomers may be used depending on the requirements of the particular application.

As will be apparent from the foregoing, other embodiments of the invention may be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be considered limited only by the scope of the claims.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an embossed gasket with a filler according to the invention; Figure 2 shows the embossment in the uncompressed state, line 2 in Figure 1.
FIG. FIG. 2A is a cross-sectional view similar to FIG. 2 showing an embossing according to another embodiment of the present invention. FIG. 3 is a cross-sectional view showing the embossing of FIG. 2 in a compressed state. Figure 3A shows the second
A cross-sectional view showing the embossing in Figure A. 10...Gasket assembly, 12...Body,
14, 16... Main surface, 20, 22... Opening, 3
0, 31...Emboss, 32...Protrusion, 34...
... Recessed portion, 36 ... Filling member, 40, 42 ... Opposing surface, 112 ... Body, 114 ... Metal sheet, 116 ... Layer, 118, 120 ... Main surface, 1
30...Emboss, 132...Protrusion, 134...
...Recessed portion, 136...Filling member.

Claims (1)

[Claims] 1 An embossed gasket for compressing between a pair of opposing surfaces, at least one of which defines an opening, to form a seal between the opposing surfaces, the gasket being made of metal. a body comprising a sheet, the body having a pair of spaced apart major surfaces, and the body having at least one through aperture formed therein that surrounds the aperture; the body also has an elongated embossment substantially completely surrounding the through-opening, the emboss being spaced from the through-opening for sealing in a zone of the embossment; has a protrusion projecting outwardly from one major surface and a corresponding recess extending inwardly from the other major surface, and the recess is screen printed. A resilient elastomeric sealant material only partially fills the recess, and the sealant material is retracted within the recess, thereby removing the odor trapped in the recess. (O) ring is operative such that the thickness of the sealant material is no greater than the thickness of the metal sheet such that when the embossment is compressed between the pair of opposing surfaces, the The sealant material acts as an O-ring to support and recess the embossment to prevent flattening of the embossment, thereby causing the gasket to compress between the pair of opposing surfaces. The gasket is adapted to concentrate the sealing effect of the embossment in the zone of the embossment, further preventing leakage between the pair of opposing surfaces and increasing the sealing effect of the gasket.