JPH02195077A - Heat resisting gasket - Google Patents

Abstract

PURPOSE:To manufacture a gasket easily and make it possible to provide its stable seal quality by covering both of the front and rear, and the side of gas passage port of the composite mica core sheet formed into a given gasket shape with a heat resisting metallic thin plate. CONSTITUTION:This heat resisting gasket consists of a core sheet 1 provided with a gas passage port 4 punch-formed into a given gasket shape and four tightening holes 5, a heat resisting metallic thin plate 2 provided so as to cover the top of the sheet 1 formed into the approximately same shape as the sheet 1 and a heat resisting metallic thin plate 3 covering the bottom of the sheet 1 and the whole side of the outer periphery of the sheet 1 and the side of the gas passage port 4. Moreover, the thin plate 3 covers the section up to the top of the heat resisting metallic plate 2. It is desirable to use, for example, 0.1-0.3mm thin stainless steel, especially, stainless steel such as SUS310S, SUS304.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-resistant gasket suitable as a gasket for exhaust systems in engines of automobiles, trucks, ships, and other various means of transportation.

Exhaust gas during engine operation has a high temperature of over 500 degrees Celsius, so gaskets used in engine exhaust systems, such as exhaust manifolds and gaskets used at the connection between the exhaust pipe and turbocharger. For commercial purposes, heat-resistant materials are required that can maintain the required sealing properties even when exposed to such high temperatures for long periods of time.

In order to meet this demand, we created heat-resistant metal I on both the front and back sides of a carbon base sheet formed into a predetermined gasket shape.
A so-called walnut-type gasket covered with a 1% thin plate has been well known. This gasket was developed based on the fact that carbon exhibits extremely high heat resistance when isolated from the atmosphere, especially oxygen. It is applied for the purpose of blocking protection. This case-shaped gasket exhibits an excellent sealing effect in the above-mentioned high temperature range due to the elasticity of the internal carbon base sheet and the protective action of the external heat-resistant metal casing.

゛ Should. However, in order to completely isolate the carbon base sheet from the outside air, it is necessary to apply a heat-resistant metal thin plate on top of the wrapped-type gasket, but it is difficult to do this for all products from a commercial production perspective. However, in actual products, there are gaps between the joints of the heat-resistant metal sheets. In addition, the flange undergoes repeated thermal expansion and contraction due to the large temperature changes that occur when the engine is running and when it is stopped, and this causes the seam of the heat-resistant thin metal plate of the case-shaped gasket to become wider than when it was initially installed, causing the final Specifically, oxygen enters inside the gasket, and as a result, the internal carbon base sheet is exposed to the above-mentioned high temperature and oxygen, as well as strong vibrations from the engine that act in a direction that destroys the structure of the carbon base sheet itself. In addition, there is the problem of being destroyed in an unexpectedly short period of time.

In view of the above-mentioned drawbacks of carbon base sheets, the present inventors further attempted to develop a wrapped gasket with a core material of asbestos sheet, which has been known as a heat-resistant fiber, but even asbestos is not heat-resistant. It has also been found that practical products that are fully satisfactory cannot be obtained due to defects.

Under the above circumstances, there is a need to develop a wrapped gasket that maintains excellent heat resistance for a long time even when the heat-resistant thin metal plate is applied relatively roughly.

17j To solve the above-mentioned problems, the present invention provides at least both the front and back surfaces of a core sheet made of laminated mica formed into a predetermined gasket shape and the side surface of the gas passage opening. The present invention aims to provide a heat-resistant gasket that is covered with a heat-resistant metal thin plate.

11 times 1 calm The heat-resistant gasket of the present invention has a structure in which a core sheet made of laminated mica is covered with a heat-resistant metal thin plate. Unlike graphite, asbestos, etc., the laminated mica that forms the core material sheet can withstand high temperature heating in an oxygen atmosphere, and the mica scales that make up the laminated mica bond well to each other due to the bonding force unique to mica. that you are
and that at least both the front and back surfaces of the core material sheet and the side surface of the gas passage port are covered with a heat-resistant thin metal plate.The two points work synergistically, and the covering with the heat-resistant thin metal plate is somewhat incomplete. However, as shown in the examples below, the gasket as a whole maintains unexpected heat resistance over a long period of time under strong vibrations, and the laminated mica core sheet has moderate elasticity, making it possible to improve the gasket seal of the present invention. Contribute to sex.

The present invention will now be described in detail with reference to the drawings. FIG. 1 is a top view of one embodiment of the present invention, FIG. 2 is a sectional view taken along the line x-xl in FIG. 1, and FIG. 3 is another embodiment taken along the line X-X in FIG. 1. FIG.

In Figures 1 to 3, 1 is a core sheet that is punched into a predetermined gasket shape and has one gas passage port 4 and four tightening bolt holes 5, and 2 is a core sheet. A heat-resistant metal thin plate 3 is formed to have approximately the same shape as 1 and is provided to cover the upper surface of the core sheet 1. 3 covers the lower surface of the core sheet 1, and at the same time covers the entire outer peripheral side surface of the sheet 1. This is a heat-resistant thin metal plate that covers the side surface of the gas passage port 4 and further covers the top surface of the heat-resistant thin metal plate 2. For example, the heat-resistant metal thin plates 2 and 3 have a thickness of 0.1 to Q and 3 mm.
Stainless steel plates such as 5US31O3 and 5O3304 are particularly preferred.

In the present invention, the overlapping portions of the heat-resistant thin metal plates 2 and 3 may be welded or simply mechanically pressure-welded. , it is preferable to just mechanically press them together.

The side surface of the tightening bolt hole 5 may also be covered with the heat-resistant thin metal plate 3, but if the bolt hole 5 is not exposed to high temperature outside air when the gasket is bolted between the flanges, the second
It is not necessary to cover it with the heat-resistant thin metal plate 3 as shown in FIGS. Although the entire outer peripheral side surface of the core sheet 1 may not be covered, it is generally preferable to cover it with a heat-resistant thin metal plate 3 as shown.

The core sheet 1 may be made of only laminated mica as shown in the embodiment shown in FIG. It may be a composite structure consisting of 12.

As the metal plate 11, a metal plate having hooks on both sides, which is conventionally known for steel vests, can be used. The metal plate 11 may be provided inside or on the surface of the mica sheet assembly. Further, instead of the metal plate 11, a plate having a hook on one side or a simple flat plate without hooks on both sides, which are conventionally known for use in power vests, may be used.

Mica generally has excellent heat resistance, so in the present invention, one or more scales of various types of mica, such as gold mica, white mica, and silk mica, are used as the aggregated mica for forming the core sheet. In particular, the aspect ratio (ratio of surface area to scale thickness) is at least 50. Preferably, a paper made of at least 100 scales can be used. Among various types of mica, Tnterna
ttonalStandard [505023-19
The heat resistance temperature evaluated according to 77 (E) or/and the weight loss temperature defined below is 500 ° C or more, especially 7
Particularly preferred are those having a temperature of 00°C or higher, such as gold mica such as phlogovite.

Weight loss temperature: Samples that have been heated and dried in advance at 105° C. for 2 hours are heated at various temperatures for 1 hour, and the amount of weight loss due to heating at each temperature is measured.

At this time, the lowest heating temperature at which the weight loss due to heating is i,o1it% or more is defined as the weight loss temperature.

The aggregated mica may be completely free of adhesive or may be impregnated with an organic or inorganic adhesive. Furthermore, the aggregated mica may be a mixture of the mica scales and other organic or inorganic materials such as fibers, powders, etc. Generally, organic adhesives and other materials are heated under high temperature conditions. The firing of laminated mica causes thinning. Therefore, the content in aggregate mica is preferably 30% by weight or less, especially 10% by weight or less, and the content by heating at 700°C for 1 hour is 5% by weight or less (however, if heated at 105°C for 2 hours) The content of heat-resistant adhesives and other materials (values described below) in the mica assembly can be up to about 70% by weight, but is preferably about 50% by weight or less.

Inorganic adhesives include those that are inorganic in an uncured or semi-cured state, and those that are essentially inorganic when they act as a binder, even if they are organic. is also used.

For example, various ceramizable silicones (e.g.
Examples include CELA400 manufactured by Kansai Paint Co., Ltd., AY49-208 manufactured by Tomu Silicone Co., Ltd.), and silica-based solutions (for example, Sumiceram PN2010 manufactured by Asahi Chemical Co., Ltd.). Also preferred are silicone resin adhesives used in laminated mica tapes for forming fireproof layers of fireproof electric wires.

Examples of the organic adhesive include NBR emulsion, acrylic emulsion, and polyvinyl alcohol aqueous solution.

Other heat-resistant materials include silica-alumina, etc.
CaO-mono 80 fiber, silica fiber, alumina fiber, alumina-silica fiber, alumina-boria-silica fiber, silica-alumina-MgO fiber, calcium silicate fiber,
Potassium titanate fiber, zirconia fiber, silicon carbide fiber, silicon nitride fiber, ceramic fibers such as rock wool, glass fibers such as C glass wind fiber, E glass fiber, quartz glass fiber, stainless steel fiber, copper fiber, etc. Powders of materials constituting the above-mentioned fibers, such as high-melting point metal fibers, heat-resistant powders such as powders of talc, clay, expanded vermiculite, dried sand from rivers and coasts, and various other heat-resistant ores. can be exemplified.

As organic fibers, natural organic fibers such as aromatic polyamide, aromatic polyester, phenolic resin, carbon fiber, or other thermoplastic organic polymer or thermosetting organic polymer fibers and kraft valves can be used. . Examples of commercially available products include Kevlar (trade name) manufactured by DuPont, Twaron (trade name) manufactured by Akzo, and Kynol (trade name) manufactured by Nippon Kynor.

The core sheet 1 may be made only of laminated mica as shown in the embodiment shown in FIG. It may be a composite structure consisting of.

The thickness of the laminated mica is 0 in FIG. 2 or 3 (in this case, the total thickness of the laminated mica layers 12 on both sides).
．． It is about 5 to 2.5 mm, preferably about 1.0 to 2.0 mm. To obtain the required thickness of mica assemblage, two or more thin sheets of mica assemblies may be used one on top of the other with or without adhesive.

The present invention is an improved walnut-shaped gasket, which has excellent heat resistance even when heated to a high temperature while in some contact with the outside air as a core sheet material covered with a heat-resistant thin metal plate. The gasket of the present invention is easy to manufacture and has sufficient high-temperature sealing properties even if the sheet is somewhat incompletely covered by the heat-resistant metal thin plate. Due to its stable properties, it exhibits outstanding performance as an exhaust system gasket for various engines.

BEST MODE FOR CARRYING OUT THE INVENTION Below, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 A core sheet having the structure shown in Fig. 1 is punched out of a 2 mm thick laminated mica made by paper-making only gold mica scales, and then a 5US310S stainless steel plate with a thickness of 0.25 mm is used to punch out a core sheet as shown in Fig. 2. A walnut-shaped gasket with the structure shown in was obtained.

However, the overlapping portions of the stainless steel plates are simply mechanically pressed together.

Example 2 In place of the laminated mica used in Example 1, a 2 mm thick laminated mica made from a mixture of gold mica scales and 30 parts by weight of white mica scales per 100 parts by weight was used. A case-shaped gasket having the same structure as in Example 1 was obtained.

Example 3 Instead of the laminated mica used in Example 1, four sheets of laminated mica with a thickness of 0.5 mm made by paper-making only gold mica scales were stacked with a silicone resin adhesive interposed therebetween. A walnut-shaped gasket having the same structure as in Example 1 was obtained.

Example 4 A 1 mm thick laminated mica made by paper-making only gold mica scales was coated with 10% dry weight per 100 parts by weight of the laminated mica.
A case-shaped gasket having the same structure as in Example 1 was obtained by simply stacking two gaskets impregnated with a weight part of silicone resin adhesive.

Example 5 Two sheets of laminated mica with a thickness of 0.9 mm made by paper-making only gold mica scales were applied to both sides of a hook iron plate (thickness: 0.2 mm) having hooks on both sides to obtain a composite sheet material. Ta. From this, a core sheet having the structure shown in FIG. 1 was punched out, and then a 5US310S stainless steel plate having a thickness of 0.25 mm was used to obtain a case-shaped gasket having the structure shown in FIG. 3. However, the overlapping portions of the stainless steel plates are simply mechanically pressed together.

Example 6 A uniform mixture of 100 parts by weight of gold mica scales and 50 stacked parts of alumina-silica fiber (thickness: 1.9 μm, average length: 70 mm, manufactured by Ibiden ■, trade name: Ibi Wool J, shot product) was made into a paper. Then, a walnut-shaped gasket having the same structure as in Example 5 was made using two sheets (thickness 0.9 mm) impregnated with 10 parts by weight of silicone resin adhesive per 100 parts by weight of the paper sheet. Obtained.

Comparative Example 1 Thickness 1 made by press molding expanded graphite. 0mm,
A walnut-shaped gasket having the same structure as in Example 1 was obtained by using two carbon sheets (manufactured by Nippon Carbon Co., Ltd.) with a density of 1.0 g/cm''.

Comparative Example 2 A case-shaped gasket having the same structure as in Example 1 was obtained using an asbestos sheet having a thickness of 2 mm and a density of 1.0 g/cm''.

Each gasket of Examples 1 to 6 and Comparative Examples 1 to 2 was attached to the inlet of a turbocharger of an actual engine, and a continuous durability test of 200 hours was conducted.

As a result, there was no gas leakage in any of the gaskets of Examples 1 to 6, but traces of gas leakage were observed in all of the comparative examples.

[Brief explanation of the drawing]

FIG. 1 is a top view of one embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line X-X in FIG. 1, and FIG. 3 is another embodiment taken along line X-X in FIG. FIG. 3 is an example cross-sectional view. In Figures 1 to 3, ■ is a core sheet punched into a predetermined gasket shape, 2.3 is a thin plate of heat-resistant metal, 4 is a gas passage hole, 5 is a tightening bolt hole, and 11 is a hook. Iron plate.

Claims (1)

[Claims] 1. A heat-resistant gasket formed by covering at least both the front and back surfaces of a core sheet made of laminated mica molded into a predetermined gasket shape and the side surface of the gas passage opening with a heat-resistant metal thin plate.