JPS6329150B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method of manufacturing a gasket.

Conventionally, gaskets 1, especially for automobile engine heads, have mainly been made of asbestos, copper,
It is possible to cover the cylinder hole with a thin plate such as aluminum or iron, or to fit a ring-shaped high pressure prevention ring (grommet) 2 made of a thin steel plate into the cylinder hole corresponding part of the gasket, especially in the cylinder hole connection part. It is considered normal. Other methods have also been adopted, such as holding the asbestos in the middle with an aluminum plate and integrating it, but in any case, these methods utilize the compressibility of flocculent asbestos to achieve heat resistance. At the same time, the sealing effect is achieved by firmly fixing the parts.

However, in recent years, the use of asbestos has been pointed out as a serious source of silicosis and pollution due to the inhalation of fine asbestos dust into the human body. Depending on the situation, the suspension of fine asbestos dust in the atmosphere has come to be pointed out as a serious source of pollution.

On the other hand, from the viewpoint of precision, the compressibility of asbestos causes imbalances in the relative accuracy between the engine head and cylinder when tightened with bolts, etc., and this inaccuracy is particularly important for gaskets on the side surfaces of rotary engines. Due to its nature, it is not practical and has an impact on performance.

Furthermore, the thin metal ring (grommet) 2 at the cylinder hole connection part of the gasket is fitted to reinforce the asbestos against pressure fluctuations such as explosions, suction, and exhaust within the cylinder.
Due to the inconsistency in contact between the smooth metal surface of the ring and the roughness of the finished surface of the cylinder head, a complete airtight effect could not be obtained even against the tightening force of the bolt. .

However, with the recent shift to an overhead cam system for engines, the gasket 1 is integrally attached to the bolt on the same plane that includes the drive hole 3 and the cylinder hole 4 in order to drive the chain by interlocking the cam in the engine head. When tightening the cam chain, a large amount of oil that lubricates the cam chain may be sucked into the cylinder hole through the small gap in the reinforcing ring of the gasket, and high-pressure gas may leak, causing oil to leak outside the cylinder. It became.

Therefore, to prevent this leakage, a rubber gasket 5 for the cam chain is separately installed around the cam chain hole.
Measures have been taken to prevent oil leakage, such as providing a groove 6 to accommodate the bolt hole, or providing an O-ring groove 7 around the bolt hole and using an O-ring 8 to prevent oil leakage. The gasket deteriorated due to high temperatures, causing leaks after long periods of use. As mentioned above, gaskets mainly made of asbestos have no desired sealing effect due to the asbestos itself, and the current situation is that sealing is barely achieved by the combined use of O-rings and other gaskets.

In addition, a single soft metal has been used as a high-pressure gasket in the past, but if the gasket is made of smooth metal, the tightening pressure becomes enormous and a satisfactory sealing effect cannot be obtained. , the thin metal plate is made concentrically corrugated 11 with respect to the hole as shown in FIGS. 4 and 5, and serrated protrusions 10 are provided concentrically on both sides of the metal plate, so that the contact pressure can be controlled by line contact. Airtightness has been maintained by forming a complete line contact loop on a flat surface as a concentrated pressure.

However, when the serrated protrusions 10 are formed, a considerable tightening force is required, and on the other hand, when a corrugated metal gasket is used, there is a problem in that the corrugations 11 are deformed by pressure and the linear contact effect is lost.

Furthermore, in order to form the serrated protrusions 10 and the corrugations 11, the number of manufacturing steps must be increased, resulting in an increase in cost.

Furthermore, in order to improve durability such as heat resistance of the gasket, it has been conventionally practiced to form thin films made of heat-resistant rubber, resin, etc. on both surfaces of the gasket. For example, British Patent No. 1166370 proposes a metal gasket coated with fluororesin, and Japanese Utility Model Application Publication No. 48-70054 proposes a resin gasket coated with fluororesin. Proposed. The publication also proposes a gasket in which a circumferential rib is formed around the hole. However, in order to form the circumferential ribs, the resin substrate, which is the base material of the gasket, is bulged outward from the surface and then coated with fluorine resin, which increases the number of manufacturing steps and costs. I had the inconvenience of being expensive.

The present invention has been made in view of these points, and it is possible to extremely easily form a thick swollen portion around the gasket hole to be sealed, thereby improving gasket manufacturing efficiency and reducing manufacturing costs. It is an object of the present invention to provide a method for manufacturing a gasket that can significantly reduce the amount of gas and improve the sealing performance of the gasket.

In order to achieve this objective, in the present invention, a coating liquid made by dissolving heat-resistant rubber, resin, etc. in a solvent with a high surface tension is evenly applied to both surfaces of the gasket to form a film, and the gasket is The structure is such that a thick enlarged portion protruding from both surfaces is formed at the peripheral edge of the gasket hole provided in the gasket to be sealed by utilizing the surface tension of the coating liquid to be applied.

According to the present invention, when the coating liquid is evenly applied to the surface of the gasket, the coating liquid is drawn to the periphery of the gasket hole of the gasket by the surface tension of the coating liquid, protrudes from the surface, and automatically expands the thickened portion. is formed.

The method for manufacturing a gasket of the present invention will be explained below with reference to FIGS. 3 and 6, which show gaskets manufactured by the method of the present invention.

Gasket 9 shown in FIGS. 3 and 6
The metal plate 17 is used as a base material, and the metal plate 17
The figure shows an example in which both surfaces of the sheet are formed into a pear-like texture.

In this embodiment, before the metal plate 17 is coated with the film 13, a surface treatment is performed to roughen the surface into a pear-like texture. That is, both surfaces of a soft metal plate 17 made of aluminum, copper, etc. are subjected to mechanical processing such as blasting or chemical surface treatment such as etching to uniformly form a non-directional fine pear-like texture. to vandalize. FIG. 6 shows an enlarged cross section of the gasket, and both surfaces of the metal plate 17 are satin-like surfaces 12, 12'.

According to the present invention, for the metal plate 17 formed in this manner, heat-resistant rubber such as fluorine rubber or silicone rubber, fluorine resin, etc. is dissolved in a water-soluble solvent having a high surface tension. Apply the coating liquid
The coating 13 is formed by uniformly applying it to both satin-like surfaces 12, 12' of the metal plate 17. Due to its surface tension, the applied coating liquid is attracted to the peripheral edge 15 of the gasket hole 14, which is a perforation to be sealed, such as an oil hole including a bolt hole, provided in the gasket, and is slightly smaller than the surface of the coating 13 on the flat area. The thickened portions 16, 16' that protrude to the external force are formed, and while this state is maintained, the coating liquid solidifies and the coating is completed.

As described above, in this embodiment, by utilizing the surface tension of the coating liquid, it is possible to form a thickened portion that increases sealing performance at the peripheral edge of the gasket hole simply by applying the same coating liquid to the gasket. Therefore, no special process is required to form the enlarged portion with the same thickness, and the manufacturing process is simple and quick, and the manufacturing cost is low.

Note that when both surfaces of the metal plate 17 are made to have a satin-like surface 12, 12' as in this embodiment, the surface of the coating 13 formed thereon also becomes a satin-like surface.
Sealing performance is further improved. In other words, both mating surfaces to be sealed are tightly tightened and point-contacted with each other with countless irregular micro-gaps, and these micro-gaps are finely adjusted to form a microscopic, non-directional surface. The labyrinth effect is exhibited and the sealing performance is improved.

Further, since the metal plate 17 is made of a soft material such as aluminum, it can be sufficiently plastically deformed against the tightening pressure, and sufficient sealing performance against the mating surface can be obtained.

Note that although the above embodiments were applied to a metal gasket, the present invention can be similarly applied to any gasket made of resin or the like.

Since the gasket manufacturing method of the present invention is structured and operates in this manner, it is possible to extremely easily form a thickened portion around the gasket hole to be sealed, thereby improving gasket manufacturing efficiency. At the same time, the manufacturing cost can be greatly reduced, and the sealing performance of the gasket can also be improved.

[Brief explanation of drawings]

FIG. 1 is a plan view of a conventional engine gasket. FIG. 2 is a longitudinal cross-sectional view showing a state in which a conventional engine gasket is installed. FIG. 3 is a plan view of the gasket of the present invention. FIGS. 4 and 5 are longitudinal sectional views showing conventional pipe gaskets. FIG. 6 is an enlarged view showing the state of the perforated portion of the gasket of the present invention. 9... Gasket, 12, 12'... Pear-grained surface, 13... Coating, 14... Gasket hole, 1
5...Peripheral part, 16, 16'...Thickness enlarged part, 1
7...Metal plate.

Claims (1)

[Claims] 1. A coating liquid made by dissolving heat-resistant rubber, resin, etc. in a solvent with high surface tension is evenly applied to both surfaces of the gasket to form a film, and the periphery of the gasket hole to be sealed provided in the gasket is coated. 1. A method for manufacturing a gasket, characterized in that, by utilizing the surface tension of a coating liquid to be applied, thick enlarged portions protruding from both surfaces are formed on the gasket.