JPS592784B2 - Gasket for cylinder head of internal combustion engine and method for manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a gasket for a cylinder head of an internal combustion engine and a method for manufacturing the same.

15 Conventionally, gaskets for cylinder heads of internal combustion engines are broadly classified into the following two types.

One of them is called the steel best type, which has a core material made of a thin metal plate with many important protrusions on both sides and gasket material attached to both sides, or one with a similar structure and a metal core material. It is made of mesh material made by.

The other type is the power vest type, which has a structure in which the core material and gasket material are arranged in the opposite direction.
5. A thin metal plate with important protrusions on only one side is attached to both sides of the gasket material. The core material with the metal important monument protrusion is generally made of a mild steel plate, the thickness of which is approximately 15mm-O, and 30,772m. rectangular), square, Ξ-gon, trapezoid (simple sentence with upper wide and lower narrow shape), etc.
In each case, a protruding pawl passes through the gasket material, and its tip is bent to hold the gasket material.

35 The metal mesh material used as the core material is generally made of plain woven metal wire, and the metal wire is made of mild steel, stainless steel, etc., and has a wire diameter of about 0.2 to 0.5 mm. It is being

The gasket material is often made from a slurry of asbestos fibers fixed with synthetic rubber, synthetic resin, etc. in water and made into a sheet by a papermaking method.

In addition, this paper sheet product is made of a combination of non-metallic inorganic fibers, metal fibers, and boron nitride instead of asbestos fibers,
Combinations of asbestos fibers, graphite or mica powder scales, rubber, vulcanizing agents, fillers, etc. have been proposed. Other gasket materials include asbestos fibers, synthetic rubber (or natural rubber), synthetic resins, inorganic fillers, etc., which are kneaded into a compound with an appropriate viscosity using an organic solvent.
It is known to apply the above-mentioned core material to the required thickness using a friction roll, and then dry and remove the organic solvent contained therein. Further, as another gasket material, an expanded graphite sheet material has been proposed. After each of the gasket materials mentioned above is punched into a predetermined shape, a grommet process (metal ring attachment process) is applied to seal the combustion gas in the cylinder bore, and the material is used as a gasket for the cylinder head of an internal combustion engine. There is.

As mentioned above, most of the gasket materials conventionally used in engineering utilize asbestos fiber's good properties such as chemical resistance, flexibility, and physical resistance, and are made using asbestos fiber as the main ingredient. It consists of a mixture of However, the asbestos fiber (chrysotile asbestos) used in the gasket material gradually releases crystal water at a temperature of about 400'C, and as a result, it deteriorates, does not lose strength, and has poor elasticity. Therefore, various means to compensate for this have been proposed, but no research and development has been conducted on a gasket material that can maintain physical resistance and elasticity in a high-temperature range exceeding the above-mentioned temperature. Expanded graphite sheets, which have been proposed as an alternative to asbestos gaskets, have the disadvantage that in an oxidizing atmosphere, like asbestos fibers, oxidation progresses when the temperature exceeds approximately 400°C, and if oxidation progresses for a long time, the sheets sublimate and disappear. be. In addition, in the manufacturing method of gasket material, if a slurry in which the gasket material composition is dispersed in water or an organic solvent is used. Since the drying and evaporation processes that remove water or organic solvents cannot be removed, the residue where the solvent is removed becomes a cavity, and the volume ratio of the cavity is as high as 40 to 50%. As a measure to reduce the number of cavities, attempts have been made to compress them with rolls or presses during the process of stacking them with core materials etc. to form a composite, but the above manufacturing method produces only a few large cavities. It is not composed of fibers, but is a collection of countless extremely fine cavities, and exists in the intertwining of the fibers of the main component, so even if compression is applied in a dry state with no solvent, these fine cavities will disappear. It is very difficult to close the cavities, and even gasket materials that have undergone the compression process still have cavities of 10 to 20% by volume, so leakage paths that connect these minute cavities should be used to seal from the gasket material itself. There is a defect that causes fluid to seep out.

However, in the case of a gasket for the cylinder head of an internal combustion engine, the combustion gas of the fuel, lubricating oil for lubricating the mechanical parts of the engine (engine oil and cooling water for cooling the heat of the combustion gas) are used. These three fluids must be sealed at the same time with one gasket, so a semi-metallic (metal-coated gasket) structure is used, which is covered with metal plate grommets to seal out the high temperature combustion gas around the cylinder bore. In addition, the openings for cooling water and lubricating oil are sealed with a composite gasket material that has been punched out.The sheet material for this cylinder head gasket has a composition that To reduce the number of microscopic cavities inside the body,
Rubber-binding fillers (usually oil-resistant synthetic rubbers) are used. This invention was made in order to solve the above-mentioned drawbacks of the conventional gasket, and in particular, it is a gasket that does not lose its strength and elasticity even in a high temperature range of 400°C or higher, and that is in a composite state. The main object of this invention is to provide a gasket for a bower head of an internal combustion engine, in which cavities (voids) inside the material are kept to a minimum and the sealing effect is greatly enhanced, and a method for manufacturing the same.

A gasket for a cylinder head of an internal combustion engine according to the present invention is made of expanded vermiculite flaky material 4.
A sheet of a composition consisting of 0 to 80% by weight, 1 to 30% by weight of fibrous material, 5 to 40% by weight of fine filler particles, and appropriate amounts of a binder and a crosslinking agent, and a metal plate provided with prongs are laminated. It is characterized by the fact that it is

Materials generally known as scaly laminated materials include mica and graphite in addition to vermiculite, and methods for expanding them into scaly shapes include, for example, applying chemicals between the scaly laminated materials. It is known that by heating the chemical to the decomposition temperature after infiltration, the expansion force causes the layers to separate and an expanded substance can be obtained.

In the case of vermiculite, by rapidly exposing it to a high-temperature atmosphere such as a rotary kiln near 1000°C, the interlayer crystallization water of the scale laminated structure rapidly evaporates, and the expansion pressure causes the interlayers to separate. The industrial method of vermiculite has been put into practical use. When comparing the two different processing methods mentioned above, the former requires complicated methods such as chemical treatment and heat treatment, which has the disadvantage of increasing manufacturing costs. wood,
General industrial materials (materials) such as spraying materials and paint modifying materials
It is used as. The reason why this invention focused on expanded vermiculite among the scale-like laminated materials is based on the above-mentioned reasons.

The vermiculite belongs to a three-layered clay mineral and has a structure similar to biotite, and the structural formula of pure vermiculite is 1.
．． According to Barshad (1948).

This crystalline (internally absorbed) water in vermiculite only begins to be lost when it is heated above 700°C, so this point makes it more heat resistant than asbestos fibers, which release crystallized water at temperatures above 400°C. It is advantageous for

When vermiculite is expanded using the method described above, its volume has expanded by 5 to 20 times, but it is also possible to form a sheet by physically bonding the expanded vermiculite particles together. , the joint surface strength is very weak and only brittle products can be obtained.

However, it is possible to disperse expanded vermiculite in water and apply shearing force using a high-speed mixer, or to apply shearing force in a dry state using a device integrator such as Miracle Mill to form scaly flakes with interlayer separation. The inventor's experiments have confirmed that a flexible sheet with strong joint surface strength can be obtained by bonding the peel-active surfaces together. It has also been found that in order to obtain strong activity of the exfoliating active surface, it is optimal for the diameter of the scale-like flakes to be in the range of 10 meshes to 60 meshes and the thickness to be 100 μm or less. As mentioned above, the material is mainly made of expanded vermiculite flake material, and fiber material and
According to the composition containing fine powder particles, a binder, and a vulcanizing agent, a gasket sheet in which materials of different shapes such as vermiculite flake material, fiber material, and fine powder particles are in a close-packed state with each other. is obtained.

On the other hand, since the sheet-like material of the conventional gasket has a composition mainly composed of fibrous material, close packing cannot be achieved and the final voids (voids) cannot be reduced. As described above, this results in defects in sealing performance. The filling degree of the conventional sheet mainly composed of fibrous material and the composition of this invention mainly composed of vermiculite scaly flakes and added with fibrous material and fine powder particles is J.
The table below shows a comparison of the bulk densities determined by the IS cylindrical method.

As a result of the above experiments, the composition that exhibits the closest packing effect in accordance with the gist of the structural action of the present invention is, as described above, 40 to 80% of scale-like flakes, 19 to 30% of fine powder particles, and 1 to 3% of fibrous material.
It was found that a range of about 0% is good.

In this invention, non-metallic inorganic fibers, metal fibers, etc. other than asbestos fibers can be used as the fibrous material.

In other words, the fiber material used in this invention is not just non-metallic fibers such as carbon fibers, phenol fibers, and ceramic fibers, which were traditionally difficult to form into sheets by themselves, but also stainless steel. It is possible to apply metal fibers such as fibers and brass fibers.

However, the gasket for the cylinder head of an internal combustion engine using the above-mentioned fibers has the advantage that the heat of explosion and combustion of the fuel is released to the cooling water hole through the reinforcing metal plate through the metal grommet material applied to the cylinder bore. There is.

In cases where asbestos fiber is used as the main component of the gasket sheet material, such as in conventional products, combustion heat is absorbed into the gasket because asbestos fiber is a material with low thermal conductivity that makes it difficult to conduct heat. It has the disadvantage of accumulating heat and promoting deterioration of physical properties due to heat. However, non-metallic fibers such as glass fibers and metallic fibers such as stainless steel fibers applied in this invention are both fibers with high thermal conductivity compared to asbestos fibers.
Heat can also be actively released from the seat part. In particular, when metal fibers such as stainless steel fibers are used, the heat resistance is dramatically improved due to the synergistic effect with the heat resistance of vermiculite. The table below compares the conventional product and the invention product in terms of thermal conductivity, tensile strength, and rate of change in tensile strength after heating. The method for producing a gasket according to the present invention includes a sheet of a water-containing composition comprising an expanded vermiculite flake material, a fiber material, fine filler particles, an appropriate amount of a binder, and a crosslinking agent, and protrusions. After forming a composite plate by laminating the composite plate and the metal plate in a wet state, the composite plate is compressed with a roll or a press to orient the vermiculite flake material and to combine the composition and the metal plate. It is characterized by forming a dense integral structure.

In particular, as a method for forming the composition into a sheet shape,
It can be applied to any of the conventional methods such as papermaking, coating, and extrusion, and does not require any new special manufacturing equipment, making it possible to manufacture high-performance sheet materials at low cost and easily. There are advantages.

Furthermore, after composite lamination with the reinforcing metal plate, when roll pressing or press pressing is performed in a wet state (semi-dry), vermiculite and scaly flakes are oriented in the direction of the sheet surface, so the flakes are combined with the fiber material and filling. In addition to the close packing with the material fine particles, the active surfaces of the scale-like flakes in the part that was originally the laminated surface come into surface contact again, resulting in flexibility that could not be obtained with fiber-based sheet materials. This sheet material has the advantage of imparting properties.

The results of the test conducted according to the JISR3453 standard flexibility test method are shown in the table below. However, the flexibility D value is a coefficient of the degree to which cracks or breaks do not occur when the sample is wrapped around a metal round bar 180 times (metal round bar diameter/sample thickness), and the smaller the value, the more flexible it is. Show that you are working. The graph in Figure 1 shows the relationship between the density and tensile strength of the sheet after pressing, and it especially compares sheets that are rolled or pressed in a dry state to orient the scale-like flakes in the direction of the sheet surface. This is in contrast to the example.

When the composition is compressed, as the density increases due to the compression, the scale-like flakes are oriented in the direction of the sheet surface, and the active surfaces of the scale-like flakes in the portion that was originally the laminated surface come into surface contact again. , the tensile strength increases due to the bonding strength, but as shown in the graph above, sheets pressed in a wet state (semi-dry state) have the same density compared to sheets pressed in a dry state. It was observed that the tensile strength of 2.

This is because the exfoliation active surface of the scale-like flakes is wet.
This is due to the fact that more active binding action is exerted, and its tensile strength can be said to be an epoch-making strength created by the synergistic effect with the close-packing effect of the composition described above. Note that when a wet sheet is stacked on a reinforcing metal plate and then compressed with a roll or press, the moisture in the sheet is squeezed out by the compression force, and as the moisture moves, a flow (flow) occurs in the sheet. phenomenon) occurs, which inhibits the improvement of density.However, it is possible to interpose a piece of paper, woven cloth, blanket, etc. between the composite material and the roll (press) to absorb the squeezed water. The density can be easily increased by squeezing. Next, the advantages of applying the gasket having the above structure to the cylinder head of an internal combustion engine will be described.

Regarding gaskets for cylinder heads of internal combustion engines,
As mentioned above, three fluids: combustion gas from the fuel, lubricating oil (engine oil) to lubricate the mechanical parts of the engine, and cooling water (cooling water) to cool down the heat generated by the combustion gas are combined into one gasket. Because of the need to simultaneously seal the three fluids, gaskets are designed for each location to suit the different fluid characteristics of each of the three fluids.

For example, the cylinder bore is covered with a semi-metallic grommet to seal out high-temperature, high-pressure combustion gas.
The basic structure of a gasket for a cylinder head of a typical internal combustion engine is that the openings for cooling water and lubricating oil are sealed using the characteristics of a composite gasket material that is punched out. Recently, however, the use of aluminum alloy castings as cylinder head materials has become commonplace for reasons such as reducing the weight of engines and improving cooling efficiency.However, due to problems with the structural strength of aluminum alloys, cylinder head There may be restrictions on the tightening force for tightening the gasket,
Distortion of the cylinder head may cause a partial shortage of tightening surface pressure. These phenomena change depending on the designer's viewpoint for each internal combustion engine, so the tightening surface pressure is investigated depending on the internal combustion engine to which it is applied, and flanges are added to areas where the tightening surface pressure is insufficient. Partial treatments (dipping, coating, overlaying, etc.) are performed using sealants that have good compatibility with surfaces.

On the other hand, in the case of the gasket according to the present invention, the sheet material is mainly composed of scale-like flakes, to which fiber material and fine powder particles are added to form a close-packed state, and the scales are formed by rolling or pressing. Since the shaped flakes are oriented in the direction of the sheet surface, it has excellent flexibility and sealing properties that cannot be obtained with gaskets made mainly of fiber materials.
In addition, even when exposed to an atmosphere of 400°C or higher, the strength decreases little, elasticity is maintained, and the gasket described above has the ability to prevent sealing performance and torque down due to thermal deterioration. It can fully accommodate three fluids. In particular, by applying non-metallic fibers other than asbestos fibers (glass fibers, carbon fibers, etc.) and metal fibers (stainless steel fibers, brass fibers, etc.), it is possible to prevent the effects of asbestos fibers on the human body, which can be severe when handled. First, due to heat transfer through metal fibers,
It is also possible to improve the cooling efficiency of the internal combustion engine and the durability of the gasket.

Furthermore, the gasket for the cylinder head of an internal combustion engine according to the present invention has the advantage that it can be manufactured using conventional equipment without requiring special manufacturing equipment, and can be manufactured using an inexpensive material called expanded vermiculite as the main component. The economical effects are great.Examples of the present invention are shown below.

Example 1 No. 3 vermiculite raw stone was fired and expanded rapidly in a rotary kiln at 900'C, and the expanded vermiculite was sheared at high speed in a miracle mill to produce scaly flakes with a scale diameter of 50 mesh and a scale thickness of 35 μm. None, this scaly flaky vermiculite 41k9, glass fiber 4k9 with a fiber diameter of 12 μm and length of 10 mm, and 22 kg of clay with a particle size of 7 μm or less are dispersed in 1000 tons of water, and while stirring this dispersion (slurry), synthetic rubber latex is added. 4kg of vulcanizing agent 0.3k9 is added, and this slurry is made into paper using a paper making machine and dried to form a vermiculite sheet material with a thickness of 1.5 mm and a bulk density of 0.789 x Koji 3 D. This sheet material Mild steel plate 0.2
After stacking and pressing on both sides of a mm-thick thin metal plate with triangular nail stands on both sides, the scale-like flakes of vermiculite sheet material are oriented in the surface direction of the metal plate using a pressing tool. , density of sheet part 1.59/CwL3
The gasket material is made of gasket material with an overall thickness of 1.8 mm. This gasket material is punched to the specified dimensions of a commercially available head gasket, and a stainless steel plate (S
US3O4) A gasket for a cylinder head of an internal combustion engine was obtained by applying a grommet with a thickness of 0.22 mm.

Figures 2 and 3 show the gasket.
1 is vermiculite sheet material, 2 is reinforcing metal thin plate,
3 is a cylinder bore portion, 4 is a grommet thereof, 5 is a cooling water hole, 6 is a lubricating oil hole, 7 is a grommet, and 8 is a bolt hole.

Tighten the gasket above to the cylinder head of an automobile internal combustion engine with a bolt torque of 800 kgf-? Assembled and engine speed 6000r. p. When a cold forced cyclic bench operation durability test of engine cooling water was conducted, good results were obtained as shown in the table below. Example 2 No. 2 vermiculite rough stone was placed in a rotary kiln at 900'C, and 55kg of expanded vermiculite was heated and expanded in 150J of water. ．． This was then put into a pen-shell type high-speed mixer and sheared at high speed in water to form a water-dispersed slurry of scale-like flakes with a scale diameter of 30 mesh and a scale thickness of 23 μm.This was transferred to a machine chest, and after adding 1,350 tons of water, it was pulped. Add 2 kg of stainless steel fibers with a fiber diameter of 12 μm, and 37 kg of clay with a particle size of 7 μm or less, and disperse them uniformly. While stirring this slurry, add synthetic rubber latex 5K9 and 0.4 kg of a vulcanizing agent, and continue stirring. The synthetic rubber latex is completely fixed by gradually adding sulfuric acid at a concentration of 5%, and this slurry is made into paper using a paper making machine to make a 2 mm thick vermiculite sheet material. After stacking and pressing on both sides of a thin metal plate with a diameter of 0.25 mm and having grater-like triangular claws on both sides, a blanket is placed on both sides, and the water is squeezed out using a hydraulic press. This was dried in an oven at 110°C to a thickness of 1.4 mm and a density of 1.79. /cm3 gasket material, punched this gasket material to the specified dimensions of a commercially available gasket, and attached a mild steel plate SPCC with a thickness of 0.2 m to the cylinder bore part.
m, with a grommet of 3 mm width, and a copper plate C in the lubricating oil hole.
Up with grommets of 0.15 mm thickness and 2 mm width,
Furthermore, a gasket for a cylinder head of an internal combustion engine was obtained, in which the part corresponding to the chain case part was partially treated with a synthetic rubber sealant to a film thickness of 0.05 mm (see FIG. 2).

Tighten the gasket above to the cylinder of an automobile internal combustion engine with bolt torque 7501<9f-? After assembling the product, we carried out 50 cycles of heating and cooling cycling, using steam led from the boiler to the cooling water passage for 30 minutes, and then switching to tap water for 30 minutes, with good results as shown in the table below. was gotten.

As described above, according to the present invention, as a gasket for a cylinder head of an internal combustion engine, it has excellent sealing performance against the three fluids of combustion gas, lubricating oil, and cooling water, and moreover, A gasket that does not lose its strength and elasticity even in high-temperature regions and has excellent performance that can withstand long-term use can be obtained.

[Brief explanation of drawings]

Fig. 1 is a graph comparing the physical properties of the gasket of this invention and a conventional product, Fig. 2 is a plan view of a gasket showing an embodiment of the invention, and Fig. 3 is an enlarged sectional view of a part thereof. It is.

Claims (1)

[Claims] 1. Expanded vermiculite scaly flake material 40
~80% by weight, fibrous material 1-30% by weight, filler fine particles 5
A gasket for a cylinder head of an internal combustion engine, characterized in that a sheet of a composition comprising ~40% by weight of a suitable amount of a binder and a crosslinking agent and a metal plate provided with protrusions are laminated. 2. The gasket for a cylinder head of an internal combustion engine according to claim 1, wherein the fiber material is one or more of pulp, stainless steel fiber, glass fiber, and ceramic fiber. 3. A sheet of a water-containing composition comprising an expanded vermiculite flake material, a fiber material, fine filler particles, an appropriate amount of a binder and a crosslinking agent, and a metal plate provided with protrusions are laminated in a wet state. After forming a composite plate, the composite plate is compressed using a roll or a press to orient the vermiculite flaky material and form a dense integral structure of the composition and the metal plate. A method of manufacturing a gasket for a cylinder head of an internal combustion engine. 4. The method of manufacturing a gasket for a cylinder head of an internal combustion engine according to claim 3, wherein the fiber material is one or more of pulp, stainless steel fiber, glass fiber, and ceramic fiber.