JPH0635735U - gasket - Google Patents

Abstract

(57) [Abstract] [Purpose] Absorbs the roughness of the joint surface due to minute scratches,
Moreover, to provide a gasket that can maintain the sealing performance for a long time. [Structure] On the first surface plate 8 side where an expanded graphite layer 22 is formed on a metal plate 24, the second surface plate 10 is folded back around a seal hole 12 to form a folded portion 14 to form a gasket 1. Formed. [Effect] Since the expanded graphite layer 22 does not cause a flow, it is possible to maintain the sealing performance for a long period of time.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a gasket made of a metal plate and expanded graphite.

[0002]

[Prior art]

 It is well known that a metal laminated gasket in which a plurality of thin metal plates are laminated is widely used in diesel engines and the like. A general structure of the metal laminated gasket will be described with reference to FIG. In FIG. 5, the metal laminated gasket 1 has a bead 4 formed on a substrate 2 made of a hard metal plate such as spring steel, and an auxiliary plate 6 for adjusting the compression height of the bead 4 and surface plates 8 and 10. Are laminated, and the surface plate 10 is folded around a seal hole 12 such as a cylinder hole to form a folded-back portion 14, which is superposed on the surface plate 8.

[0003]

[Problems to be solved by the device]

 By the way, in general, the engine joint surface where the gasket contacts will have fine scratches such as tool marks generated during processing. Therefore, there is a problem that the sealing fluid leaks through the tool mark even if the sealing pressure by the bead acts on the joint surface. Therefore, conventionally, a sealing material such as synthetic resin or rubber is coated on the surface of at least the portion where the bead is provided to seal a minute gap such as a tool mark. Generally, since the roughness of the joint surface is about 8 to 15 μm, the thickness of the coating is usually about 20 to 40 μm.

However, when a repeated load of about 50 to 100 kgf / cm ² is applied to the sealing material at a temperature of about 100 ° C., a flow phenomenon occurs in the coating film and the film thickness is reduced. Therefore, gaskets such as cylinder head gaskets to which repeated loads are applied have a problem that gas leakage may occur after long-term use. Further, as another problem, there is a risk that a sealing fluid such as gas may penetrate into the metal laminated gasket 1 from between the folded-back portion 14 and the surface plate 8 and leak out from between the laminated plates.

An object of the present invention is to provide a gasket that can absorb the roughness of the joint surface due to minute scratches and the like and can maintain the sealing performance for a long period of time.

[0006]

[Means for Solving the Problems]

 The structure of the gasket of the present invention for achieving the above object is a seal surrounding a sealing hole on a substrate provided with an opening for aligning the sealing hole and / or at least inside the opening. And a second surface plate formed by laminating a first surface plate on which a metal plate is coated with expansive graphite on one side of the substrate with the coating layer facing the front side, and the other side being a metal plate. The face plates are laminated, and the second surface plate is folded back to the first surface plate side around the hole for sealing to form a folded portion.

The second surface plate may also be a metal plate having an expanded graphite layer formed on the front side of the flat portion. Expanded graphite has great compressibility, flexibility, does not cause the flow phenomenon of organic sealing materials, is chemically stable, and can withstand a high temperature of about 400 ° C even in air. The surface roughness can be covered and the sealing performance can be improved. For example, the one in which expanded graphite with a thickness of 50 to 70 μm is adhered on a metal plate can cover a finish roughness of 15 to 20 μm, and it is possible to cover the finished graphite with a sufficient thickness of 50 μm. It is also possible to cover the above finishing roughness. The expansive graphite may be produced by a usual means supplied to the market and used in the form of a plate or sheet.

The seal portion may be formed by a wire ring arranged inside the opening, or may be formed by a bead surrounding the opening provided in the substrate, or they may be used together. Further, the folded-back portion may be laminated on the first surface plate, or may be formed in a free end shape without laminating the opening edge aligned with the hole to be sealed. .

[0009]

【Example】

 Hereinafter, the present invention will be described in detail by way of examples with reference to the accompanying drawings. FIG. 1 (Embodiment 1) shows a seal hole 12 portion composed of a cylinder hole of a gasket 16 implemented as a head gasket of a diesel engine. The substrate 2 forms an opening 20 that aligns with the sealing hole 12 and forms a bead 4 surrounding it. Then, the wire ring 18 made of low carbon steel was arranged inside the opening 20 of the substrate 2, and the bead 4 and the wire ring 18 formed a seal portion.

The first surface plate 8 is composed of a graphite-metal composite plate in which an expanded graphite layer 22 is attached to a metal plate 24, and has an opening 20 ′ that matches the opening 20 of the substrate 2. The auxiliary plate 6 was interposed between the two and laminated on one side of the substrate 2. The second face plate 10 is laminated on the side opposite to the first face plate 8 and folded back inside the wire ring 18 toward the first face plate 8 side so that the opening 20 'of the first face plate 8 is formed. The folded portion 14 extending to the covering position was laminated on the first surface plate 8. The other sealing holes (not shown) of the gasket 16 were formed in the same manner as in FIG. 1 except that the sealing portion was formed only by the beads.

As shown in FIG. 1, the gasket 16 prevents the first surface plate 8 provided with the expanded graphite layer 22 from leaking from between the engine-side joint surface (not shown) and the surface plate 8. The expanded graphite layer 22 prevents the sealing fluid from entering between the surface plate 8 and the folded portion 14. That is, since the expanded graphite layer 22 has high flexibility, when the surface plate 8 is bent between the folded portion 14 and the auxiliary plate 6, the expanded graphite layer 22 easily follows the metal plate 24. Since it can be bent to the right, it is possible to reliably prevent the risk that the fluid sealing the portion will enter the gasket 16 and leak out from between the laminated plates. When the gasket 16 of Example 1 was used by disposing the first surface plate 8 on the cylinder block side (not shown), a high sealing property could be maintained for a long period of time.

FIG. 2 (Example 2) is different from Example 1 in that the seal portion is formed only by the wire ring 18. Similar to the first embodiment, the gasket 16 of the second embodiment was also able to maintain the sealing property with the joint surface (not shown) and the prevention of leakage from between the laminated plates for a long period of time. FIG. 3 (Embodiment 3) is implemented as a head gasket for a gasoline engine, and therefore, like the previous embodiment, the portion of the gasket 16 which is a cylinder hole of the seal hole 12 is shown. Sealing portions of the third embodiment, the bead 4 ₁ provided on the substrate 2 was formed by a bead 4 ₂ provided on the second surface plate 10 adjacent to the outside of it. Then, the first surface plate 8 uses a composite plate of the expanded graphite layer 22 and the metal plate 24, and the opening 20 'is formed to have a diameter larger than the outer circumference of the folded portion 14. The first surface plate 8 is integrated with the other laminated plates 2 and 10 by means such as caulking which is usually a gasket (not shown). Sealing the hole, not the other illustrated, except that the bead 4 ₂ had Ministry formed a bead portion as in FIG. The gasket 16 of Example 3 was also able to maintain a high sealing property for a long period of time.

FIG. 4 (embodiment 4) is a modification of the embodiment 1 shown in FIG. 1, in which the bead 4 is arranged with the direction of the face plate 8 side. Similar to the gasket 16 of Example 1, the gasket 16 of Example 4 was also able to obtain high sealing performance against the sealing performance of the joint surface and the leakage between the laminated plates.

[0014]

[Effect of device]

 Since the gasket of the present invention is configured as described above, the expanded graphite seals the tool mark on the joint surface, and the expanded graphite does not cause the flow phenomenon even if the gasket is tightened, so that the The effect is that the sealing performance can be maintained. Moreover, since expanded graphite is highly flexible, it can withstand bending, so if the surface plate is folded back and laminated on the folded portion, the sealing fluid will enter the gasket and leak between the laminated plates. Can be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a gasket of the present invention according to a first embodiment.

FIG. 2 is a sectional view of an essential part of a gasket of the present invention according to a second embodiment.

FIG. 3 is a sectional view of an essential part of a gasket of the present invention according to a third embodiment.

FIG. 4 is a sectional view of an essential part of a gasket of the present invention according to a fourth embodiment.

FIG. 5 is a sectional view of a main part of a conventional metal gasket.

[Explanation of symbols]

1 Metal Laminated Gasket 2 Substrate 4 Bead 4 ₁ Bead 4 ₂ Bead 8 1st Surface Plate 10 2nd Surface Plate 12 Seal Hole 14 Folding Portion 16 Gasket 20 Opening 20 'Opening 22 Expanded Graphite Layer 24 Metallic Plate

Claims (4)

[Scope of utility model registration request] 1. A substrate provided with an opening aligned with a hole to be sealed, and / or at least inside the opening,
A first surface plate, which forms a seal part surrounding a hole to be sealed and is coated with expanded graphite on a metal plate, is laminated on one side of the substrate with the coating layer facing the front side, and the other is formed from the metal plate. A gasket having a folded-back portion formed by laminating a second surface plate formed by laminating the second surface plate on the first surface plate side around the hole for sealing. 2. The gasket according to claim 1, wherein a metal plate obtained by laminating an expanded graphite sheet is used on the front flat portion of the second surface plate. 3. The seal portion is formed by a wire ring arranged inside the opening provided in the substrate.
Gasket. 4. The gasket according to claim 1, wherein the seal portion is formed on the substrate by a bead surrounding the opening provided in the substrate.