DE3817112A1 - Sealing material and cylinder head gasket - Google Patents

Abstract

The present invention provides a sealing material which has a reinforcing core plate formed from heat resistant fibre material, and also has, on both sides of the core plate, an expanded graphite web which is stuck on with resin, and provides a cylinder head gasket which utilises the sealing material.

Description

This invention relates to a graphite sealing material and a cylinder head gasket using this.

Graphite seals used in internal combustion engines and the like used, used as their material, as in the Japanese patent application Kokoku (verified Publication) No. 33,799 / 79, a expanded graphite sheet made by graphite particles which is a snail-like shape and compressibility have and are obtained in that graphite with a highly oriented crystalline structure, such as natural graphite, cooking foam graphite, highly oriented pyrolytic graphite, etc., with a strongly oxidizing Treated liquid, such as a liquid Mixture of concentrated sulfuric acid and nitric acid or concentrated sulfuric acid with potassium permanganate or the like to make connections with embedded To form graphite, then using the resulting product Washes water and then quickly heats it to the Connections with embedded graphite in the direction of Expand C-axis. Known graphite cylinder head gaskets are to ensure the required strength, built essentially in the following way: This is because an expanded graphite sheet is formed the two sides of a reinforcement core sheet Pressed on metal with a thickness of 0.15 to 0.25 mm, which has circular protrusions by Roll machining or the like, and by use of said projections to thereby form a sealing material to obtain; the material is in the form of the  Seal punched, and further the peripheral part of the Combustion chamber with a thin sheet of metal (the eyelet is called) provided in the form of a window-like frame. The eyelet increases the tightness of that Part, which is surrounded by the eyelet (eyelet part) to this the pressure on the eyelet at the time the seal is installed to increase, which seals combustion gas cleanly and the penetration of graphite into the combustion chamber is prevented.

In the state of the art cylinder head gasket, however, the one mentioned above is the sealing material not satisfactory what its sealing property for Oil and water concerns because of pressure on the circular Protrusions of the metal reinforcement core sheet are concentrated is used to improve the strength of the Ensure seal, and consequently under tightened Conditions where water leakage occurs can and at the peripheral part of the oil hole in the oil graphite-containing section can penetrate, causing the collapse of the graphite section (which is often "Oil collapse" is called). It also has the above Cylinder head gasket further disadvantages in that because the eyelet is in contact with the cylinder head and the Cylinder block occurs on the curved part of the eyelet, the one considerable cold hardening in the form of the deformation of the eyelet undergoes such problems as cracking in the eyelet and the leakage of combustion gas during the Operation of the engine, occur as a result of repeated exposure due to the combustion explosion and the shear force due to the difference in expansion between cylinder block and cylinder head.  

It is the aim of this invention, the above mentioned Solve problems and a sealing material as well as a Cylinder head gasket to provide good resistance against water and oil as well as excellent Have sealing properties and no oil collapse and there is no crack formation on the eyes.

This invention relates to a sealing material which is a Reinforcing core plate which is made of heat resistant Fibers is formed, as well as an expanded graphite sheet, which is attached to both sides of the core plate with resin is, and a cylinder head gasket that said Sealing material used.

The reinforcement core plate, which is made of heat-resistant Fibers is formed and used in the sealing material is a cloth or mat made of glass fibers, carbon fibers, Phenolic resin fibers, aramid fibers and the like. As for the fiber material, from a cost point of view forth preferred glass fibers. As for the comparison for a cloth with a mat, a cloth is preferred, because if the cloth sticks to the graphite sheet, that Graphite penetrates into the interstices of the texture, whereby sticking or adhering the expanded graphite sheet is improved and the resistance to oil and resistance to water are increased. The fat the reinforcing core plate is preferably 0.05 to 0.5 mm. If the core plate is too thin, difficulties will arise in their handling and in their lamination occur on the expanded graphite sheet. If you too is thick, then it can be glued to the expanded one Graphite orbit can not be improved, and thus the Airtightness not improved.  

There is no particular limitation on what the expanded Graphite sheet as long as expanded graphite is considered used their material. However, the web preferably shows a thickness of 0.05 to 0.7 mm. A web too thin is difficult to handle while a web is too thick is expensive and also tends to peel off Causing inside the web.

A preferred resin that is used to glue the reinforcement core plate to the expanded graphite sheet is used is a varnish made of thermosetting resin, such as epoxy resin, Phenolic resin, furan resin, polyimide resin and the like. The bonding can be carried out by the paint on the reinforcement core plate and / or expanded graphite sheet and then the two with press bonded to a press; the gluing however even more preferably carried out by expanding the Graphite sheet on both sides of a prepreg laminated on, by impregnating the reinforcement core plate beforehand was made with the paint, and then pass the laminated product through hot rolling leaves or glued by heating and pressing. An effortless procedure can be achieved here.

The sealing material obtained in the above-described manner is punched into the shape of the seal by a press to obtain a molded body. The cylinder head gasket is produced by gluing an expanded graphite sheet or metal foil on the peripheral part of the openings of the cylinder head gasket, namely for a combustion chamber, an oil hole and a water hole, but especially on the peripheral part of a combustion chamber, or by heat-resistant resin coated, or by providing convex parts on the peripheral part of the openings of a metal sheet and coating the sheet with heat-resistant resin on that of its sides which has the convex parts or on both sides, and the thus coated sheet on one side of the molded body in sticks in such a way that the convex parts lie on the outside (see Fig. 4).

Gluing the expanded graphite sheet or metal foil to the peripheral part of the combustion chamber and others For example, openings can be made using that resin paint carried out, which was mentioned above. The expanded graphite sheet used in gluing can be the same as that used for the sealing material is used, and is preferably heat-bonded, after being impregnated with the plastic resin has been. The thickness of the expanded graphite sheet is approximately in accordance with the design pressure on the peripheral part of the combustion chamber and the like. Even though the metal foil is not subject to any special restrictions, it is preferably an aluminum or copper foil and is preferably 25 to 100 microns thick.

If a heat-resistant resin is applied to the peripheral part of the Combustion chamber and the like applied as a coating then thermosetting resins such as Fluororesin, silicone resin, polyimide resin and the like, used. The preferred method for coating includes covering the molded body with exception the peripheral part of the combustion chamber and the like, then coating the body with a solution or Dispersion of the above-mentioned resin by means of an air spray and subjecting the coated body to the  Heat treatment. The thickness of the coating becomes approximate in accordance with the delivery date on Peripheral part of the combustion period and the like selected.

The metal sheet that is attached to one side of the molded body is preferably stainless steel sheet because of its good spring properties and corrosion resistance, and preferably has a thickness of 0.15 to 0.3 mm. The metal sheet is subjected to stamping with a press to form the combustion chamber, water hole and oil hole, and at the same time, the peripheral parts of this hole are formed into convex parts (called beads) by drawing, as indicated by reference numeral 6 in FIG. 3 is shown. The bead preferably has a width of 1.5 to 3 mm and a height of 0.1 to 0.5 mm. The heat-resistant resin coated on the side having the corrugations or on both sides of the metal sheet to improve the sealing property is preferably a thermosetting resin such as fluororesin, silicone resin and the like. Part or all of the edge of the metal sheet is bent back in the opposite direction of the bead, and the metal sheet is attached to the molded body with the bent back portion to provide a cylinder head gasket.

The strength required for a sealing material is obtained by expanding one Adhere graphite sheet to a reinforcement core plate lets that are made of heat-resistant fiber material with resin instead of using the previous reinforcement core sheet made of metal, the circular protrusions exhibited. This way is in use for a cylinder head gasket the surface pressure is compensated,  and it will have an improved sealing property obtained, the leakage of water being satisfactory is prevented.

Furthermore, instead of eyelets on the peripheral part of a combustion chamber, an oil hole and a water hole provides, especially at the combustion chamber, with a cylinder head gasket, on this part a high surface pressure is required, an expanded one Graphite sheet or metal foil attached to the peripheral part, or it becomes a coating of heat-resistant Resin applied to it, or it becomes a metal sheet laminated to it with beads, and then the resulting Gasket to one cylinder head and one Cylinder block attached, at the time of tightening an increased pressure occurs and combustion gas, Oil and water can be sealed satisfactorily.

In the drawing is:

Fig. 1 and 3 are respectively a plan view of the cylinder head gasket of an example of the present invention,

Figs. 2 and 4 each of the section along line A - A in Fig 1, or B -. B in Figure 3.

Fig. 5 is a plan view of a gasket of the prior art,

Fig. 6 shows the section along line C - C in Fig. 5 and

FIG. 7 is a schematic diagram illustrating a method for checking the leakage properties.

Some preferred embodiments according to the invention are described below using examples.

Example 1

Both on the upper and lower sides of a prepreg made by applying a coating of a phenolic resin varnish (VP 231, manufactured by Hitachi Chemical Co., Ldt.) On a reinforcing core plate made of glass cloth with a plain weave with a thickness of 0, 16 mm (FECR-1311, manufactured by Fuji Fiber Glass Co., Ltd.), became an expanded graphite sheet with a thickness of 0.38 mm and a density of 1.0 g / cm³ (trade name: CARBOFIT, manufactured by Hitachi Chemical Co., Ltd.) was laminated, and the resulting laminate was hot pressed at 180 ° C to provide a sealing material with a thickness of 0.8 mm. The sealing material was punched out to the shape shown in Fig. 1 with a punch press. Subsequently, a CARBOFIT web shaped into a ring with a thickness of 0.25 mm and a density of 1 g / cm 3 was bonded at a location 0.4 mm away from the circumference of the combustion chamber 3 , which was 2% by weight of the above mentioned VP 231 was impregnated, in a width of 4 mm and by heating and pressing, whereby a cylinder head gasket was obtained, which is provided with an adhesive part 4 , which is shown in the sectional view of FIG. 2. In Fig. 2, reference numeral 1 denotes the reinforcing core plate and reference numeral 2 denotes the expanded graphite sheet.

Example 2

In the same way as in Example 1, except for the Circumstance that a glass mat of 0.1 mm thickness (EP 4012, made by Japan Vilene Co., Ltd.) instead of the glass cloth was used, which is used in Example 1, a sealing material of 0.8 mm in thickness was obtained.

Example 3

The sealing material obtained in Example 1 was punched by a punch press in the form of a seal shown in FIG. 1. Then, the punched material was covered except for a part 4 mm wide and 0.4 mm from the periphery of the combustion space 3 , and then a liquid dispersion of tetrafluoroethylene resin (trade name: POLYFLON TC-7400, manufactured by Daikin Industries, Ltd.) sprayed with compressed air, and subsequently a heat treatment was carried out at 180 ° C. in order to obtain a cylinder head gasket which was provided with an applied coating of 40 μm in thickness.

Comparative Example 1

Both on the upper and on the lower side of an aluminum foil of 0.1 mm thickness, used as a reinforcing core plate an acrylic ester adhesive (BT-1, manufactured by Hitachi Chemical Co., Ltd.), then a CARBOFIT sheet 0.38 mm thick and laminated to a density of 1.0 g / cm³ and through Heating and pressing glued to a sealing material 0.8 mm thick.  

Comparative Example 2

A CARBOFIT sheet with a thickness of 0.7 mm was placed on both sides of a metal sheet (JIS G3141, SPCC material) 0.2 mm thick, which was provided with a number of circular projections in a pitch of 2.5 mm and a density of 1.0 g / cm³ and then bonded under a pressure of 300 kg / cm² to obtain a sealing material with a thickness of 1.2 mm. The sealing material was punched to the shape shown in Fig. 5 with a punch press. Then, a metal sheet (JIS G4303, SUS 310S) of 0.2 mm in thickness to 4 mm in width and in the form of a window was stuck on the peripheral part of the combustion chamber 3 as shown in Fig. 6 to obtain a cylinder head gasket which is provided with an eyelet 5 .

Example 4

On both sides of a prepreg made of glass cloth and epoxy resin (GE-61NS, manufactured by Hitachi Chemical Molded Products Co., Ltd.) of 0.2 mm in thickness, a CARBOFIT sheet with a thickness of 0.3 mm and a density of 1 was placed , 5 g / cm³ and then molded by hot pressing at 150 ° C to obtain a sealing material of 0.8 mm in thickness. The sealing material was then punched to the shape shown in Fig. 1 with a punch press. Then, an aluminum foil of 50 µm in thickness 5 mm in width was stuck by hot pressing using the above-mentioned phenolic resin VP 231, and at a position 1 mm from the periphery of the combustion chamber 3 to obtain a cylinder head gasket which had an adhesive member 4 is provided, which is shown in Fig. 2.

Example 5

The sealing material obtained in Example 1 was punched with a punch press to form a seal and then processed into a molded body having a combustion chamber 3 , an oil hole 8 and a water hole 7 , as shown in FIG. 3. In the meantime, a stainless steel sheet (JIS G-403, SUS-301) of 0.2 mm in thickness was subjected to a pressing process, whereby a combustion chamber, an oil hole and a water hole were punched out while beads of 2 mm in width and 0, 3 mm height were formed on the peripheral part of these openings, and the edge of the sheet was bent back by 180 ° in a direction opposite to the bead. Then, a liquid dispersion of tetrafluoroethylene resin (POLYFLON TC-7400, manufactured by Daikin Industries, Ltd.) was sprayed on that side of the processed stainless steel sheet mentioned above which had the beads, and then heat treatment was carried out at 180 ° C, one To form coating layer of 0.05 mm thickness. Then, the stainless steel sheet was laminated onto the molded body in such a manner that the side which had no coating overlay came to lie inward, and the bent part of the edge was bent back further inward to thereby place the stainless steel sheet on the to fix the molded body and thus to obtain a cylinder head gasket. Fig. 3 is a plan view of the cylinder head gasket, and Figure 4 is the section along line B -.. B in Figure 3. In the figures, 9 represents the stainless steel plate, 6 denotes the bead 1, the reinforcing core plate referred to and designated 2 the expanding graphite sheet.

Those in Examples 1, 2 and 4 above and the comparative examples 1 and 2 materials obtained for their oil resistance property, water resistance property and leakage property examined to to obtain the results shown in Table 1.

In Table 1, the "oil resistance property" means the recovery of a 50 × 50 (mm) specimen made from the sealing material after being immersed in an ASTM No. 3 oil at 150 ° C for 5 hours and the "water resistance property""means the recovery of a 50 × 50 (mm) specimen after being immersed in a 50 wt% aqueous ethylene glycol solution at 100 ° C for 5 hours. The "recovery" is obtained by compressing the test piece immersed in No. 3 oil or the aqueous ethylene glycol solution with a 22.6 mm test stamp. If the thickness of the compressed part is expressed as T ₁ under an applied preload of 7 kg / cm², the thickness under an applied main load of 350 kg / cm² as T ₂ and the thickness under the in turn applied load of 7 kg / cm² as T ₃, then the recovery R is calculated by the following equation:

The leakage property was determined in the following way: For the examples and comparative examples, 5 test pieces each with an inner diameter d of 34 mm and an outer diameter D of 50 mm, which are shown in FIG. 7, were prepared. The test piece was held between jaws 13 and 13 ' and clamped together with M10 screws 14 under a pressure of 80 kg / cm². Then, an aqueous ethylene glycol solution of 50% by weight was introduced into the space 16 from the liquid inlet 15 to apply an internal pressure to the test piece, and it was checked for the presence of leakage and staining. The internal pressure was increased in steps of 0.5 kg / cm² to 8 kg / cm², each pressure being maintained for 30 minutes.

Table 1

Table 1 makes it clear that the sealing materials from the examples compared to those from the comparative examples are superior to what the recovery after immersion in oil # 3 and ethylene glycol, and that from the comparison and examples 1, 2 and 3, that the reinforcing core plate made of cloth opposite that is superior from a mat. As for the leakage property  As for, it is evident that the materials from the examples are all fully satisfied.

Next were the cylinder head gaskets that came out Examples 1, 3, 4 and 5 and from the comparative example 2 are obtained, each installed in an engine and twice a test bench endurance test of successive Subjected to 200 hours at full load. In the Cylinder head gasket from Comparative Example 2 were at the first attempt an eye tear at one point and Stain freezing solution at one point and in the second attempt an eye tear at two points and Staining of oil observed at one point. Neither Leakage of gas, anti-freeze solution and oil and others Difficulties were encountered with the cylinder head gaskets Examples observed.

Effect of the invention

According to this invention are heat resistant by use Fiber material for the reinforcement core plate the two whole faces of the seal evenly exposed to pressure, and the sealing effect for water is improved; through the use of resin for gluing the reinforcement core plate to the expanded Graphite sheet can create a good bond between the core plate and the graphite sheet are maintained, and the durability can be improved over oil and water; can also by gluing a film of expanded Graphite or metal on the peripheral part of the combustion chamber and the like of sealing or application a coating of heat-resistant resin on it or by laminating a metal sheet thereon, the is provided with beads, the sealing property for Combustion gas, water and oil can be improved.

Claims (13)

1. Sealing material, characterized by a reinforcing core plate ( 1 ), which is formed from heat-resistant fiber material, and an expanded graphite sheet ( 2 ), which is glued to both sides of the core plate with resin. 2. Sealing material according to claim 1, characterized in that the reinforcing core plate ( 1 ), which is formed from heat-resistant fiber material, is a cloth or mat made of heat-resistant fiber material, which is selected from the group of glass fibers, carbon fibers, phenolic resin fibers and aramid fibers . 3. Sealing material according to claim 1 or 2, characterized in that the thickness of the reinforcing core plate ( 1 ) is 0.05 to 0.5 mm. 4. Sealing material according to one of claims 1 to 3, characterized in that the thickness of the expanded graphite sheet ( 2 ) is 0.05 to 0.7 mm. 5. Sealing material according to one of claims 1 to 4, characterized in that the resin which is used for bonding, a varnish made of thermosetting Resin is selected from the group epoxy resin, Phenolic resin, furan resin and polyimide resin. 6. Cylinder head gasket, characterized by a shaped body which is produced by punching out a sealing material which has a reinforcing core plate ( 1 ) which is formed from heat-resistant fiber material, and an expanded graphite sheet ( 2 ), which on both sides of the core plate with Resin is glued in the form of the cylinder head gasket, the expanded graphite sheet ( 4 ) or a metal foil being glued to the peripheral part of the openings ( 3, 7, 8 ) of the molded body with resin. 7. Cylinder head gasket according to claim 6, characterized in that the expanded graphite sheet ( 4 ) to be glued to the peripheral part of the openings ( 3, 7, 8 ) is a prepreg which is prepared by impregnation with a thermosetting resin. 8. Cylinder head gasket according to claim 6, characterized characterized in that the metal foil a Aluminum or copper foil with a thickness of 25 to Is 100 µm. 9. cylinder head gasket, characterized by a shaped body, which is produced by punching out a sealing material, which has a reinforcing plate ( 1 ), which is formed from heat-resistant fiber material, and an expanded graphite sheet ( 2 ), which is glued to both sides of the core plate with resin is, namely in the form of the cylinder head gasket, wherein a heat-resistant resin is applied to the peripheral part of the openings ( 3, 7, 8 ) of the molded body as a coating. 10. Cylinder head gasket according to claim 9, characterized characterized that the heat resistant Resin is a thermosetting resin selected from the group consisting of fluororesin, Silicone resin and polyimide resin is selected. 11. Cylinder head gasket, characterized by a shaped body, which is formed by punching out a sealing material having a reinforcing core plate ( 1 ), which is formed from heat-resistant fiber material, and an expanded graphite sheet ( 2 ), which on both sides of the core plate with Resin is glued in the form of the cylinder head gasket, wherein a metal sheet ( 9 ) is provided with a convex part ( 6 ) on the peripheral part of its openings ( 3, 7, 8 ) and coated with a heat-resistant resin on the side that is with the convex part is provided, or on both sides, and wherein the coated metal sheet is attached to one side of the molded body so that the convex part ( 6 ) is on the outside. 12. Cylinder head gasket according to claim 11, characterized in that the metal sheet ( 9 ) is a stainless steel sheet. 13. Cylinder head gasket according to claim 11 or 12, characterized in that the heat-resistant resin for coating the metal sheet ( 9 ) is fluorine resin or silicone resin.