JPH02283968A - Metallic gasket - Google Patents

Abstract

PURPOSE:To improve the sealing properties of a metallic base with its configuration simplified as well as to make bearing stress uniform with no fastening stress concentration developed while being excellent in heat resistance, and thereby make the base usable for an object with rough surfaces by letting sealing agents be applied on the whole surfaces of the front and rear of the elastic metallic base in a flat shape having holes bored as required. CONSTITUTION:A gasket 1 includes 2 cylinder bores 2, a water hole 3, a bolt hole 4, an oil hole 5 and the like. A base 10 is made of an elastic metallic sheet with heat resistance, is desirable to be elastic while it is applied with primer 11 in order that sealing agents are sufficiently adheared onto the front and rear of the base 10, furthermore, sealing agents 12 excellent in gaseous sealing properties are coated over or stuck together with the upper layer of primer 11 so as to be adhered. When pressure is applied onto the upper sections of bearing stress agents 13 by the junction surface 18 of a cylinder head 15, force is exerted onto the base 10 downward, and pressure is simultaneously applied to on the side of a bearing stress agent 13b from the junction surface side 17 of a cylinder 16, bending moment is thereby incurred on the base 10. The bearing stress agents 13a and 13b are excellent in rubber elasticity, stress thereby will never be concentrated in the base 10 at all.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a metal gasket. More specifically, the present invention relates to a metal gasket for keeping a joint between a cylinder head and a cylinder block of an internal combustion engine, a joint between a connecting surface of a pipe flange, etc. airtight, and maintaining the airtightness for a long period of time.

[Prior Art] Asbestos-based gaskets, metal gaskets, and gaskets made from a combination of these materials are known as gas sealing gaskets for engine cylinders and turbochargers. In particular, metal gaskera i~ are being used as gaskets for engine cylinder heads to improve their sealing performance due to the demand for smaller and lighter engines.

In order to improve the sealing performance of this metal gasket,
Various structures have been proposed in the past.

In Japanese Utility Model Application Publication No. 57-59952, a plurality of wavy protrusions, that is, bead portions, are provided on the outer periphery of the combustion chamber hole, and by applying pressure from both sides of the bead portion, the bead portion is deformed to improve sealing performance. What was done is listed.

Japanese Utility Model Application Publication No. 60-18247 discloses that a gasket made of a steel plate is formed with an uneven bead portion, that is, an annular groove, enclosing a water hole on both sides, and the annular groove is coated with a sealant made of silicone resin or the like. What was done is listed.

[Problems to be Solved by the Invention] The gasket described in the above-mentioned Japanese Utility Model Publication No. 57-59952 has improved sealing performance, but when the gasket is tightened from both sides, the bead portion deforms and becomes flat. At this time, stress is concentrated at the angle of this bead portion. When this gasket is used for a long period of time, the stress-concentrated parts of the gasket may break due to metal fatigue or the elastic force may become weak. Additionally, a bending process is required to create the wavy bead portion. For this reason, work hardening and work strain occur during bending, resulting in a weakened metallographic structure. It is also necessary to prepare a press mold for press processing.

The method described in Japanese Utility Model Application Publication No. 60-18247 requires a bending process to form the bead portion for the same reason as above. Furthermore, this gasket is for a water hole, and there is no description of the concept of sealing the cylinder hole exposed to high-temperature flames. In the conventional technology described above, for example, when a gasket is interposed between an engine cylinder and a cylinder head and the two are tightened with bolts, the gasket is compressed unevenly and the sealing effect differs depending on the position of the gasket.

The area close to the bolt is tightened strongly, and the further away it is, the weaker the tightening becomes. This is due to deformation of the cylinder and cylinder head, and is unavoidable as the cylinders and cylinder heads of engines that have become smaller and lighter in recent years have become thinner. This invention was devised from the above technical background, and achieves the following objects.

An object of the present invention is to provide a metal gasket with further improved sealing properties.

Another object of the present invention is to provide a metal gasket that has a simple structure and does not cause stress concentration even when the metal gasket is tightened.

Still another object of the present invention is to provide a metal gasket that can make surface pressure uniform.

Still another object of the invention is to provide a metal gasket with excellent heat resistance.

Still another object of the present invention is to provide a metal gasket that can be used for sealing surfaces with large roughness.

[Means for Solving the Problems] The present invention takes the following measures to solve the problems described above.

In a substrate made of a flat metal plate having required holes and having elasticity, and a metal gasket provided with a surface pressure agent on the front and back sides of the substrate at a distance from each other in the center, a sealing agent is applied to the entire front and back surfaces of the substrate. It is a metal gasket characterized by being coated with.

[Operation of the invention] A gasket coated with a sealant is placed between two members to be sealed. When the two members are tightened, the end surfaces of the two members first press the surface pressure agent on both sides of the gasket. The gasket is pressed by both blood pressure agents and is deformed into a wave shape, but the tightness remains fixed. The substrate deformed into a wavy shape generates a repulsive force that tends to return it to a flat plate. In addition, the surface pressure agent that became the fulcrum of the wavy deformed board achieves high surface pressure;
Since it is a soft material itself, it absorbs even the roughness of the sealing surface. Therefore, the sealant adheres closely to the end face and effectively seals the gas.

[Implementation PA] Hereinafter, embodiments of the present invention will be described with reference to the drawings. A gasket 1 shown in FIG. 1 is an example in which the present invention is applied to a gasket for an automobile gasoline engine, and is interposed between a cylinder and a cylinder head. In this embodiment, there are two cylinder bores 2, a water hole 3, and a bolt hole 4.
, an oil chamber 5, etc. Cylinder bore 2 is a hole that corresponds to the combustion chamber of the engine. The bolt holes 4 are for passing bolts for fixing the cylinder and the cylinder head. The water hole 3 is for passing engine cooling water.

The oil chamber 5 is for passing lubricating oil for lubrication.

Note that the structure of this gasket is merely an example, and the number of cylinders and the arrangement of holes are various, and the structure is not limited to the above embodiment. FIG. 2 is a cross-sectional view of the gasket shown in FIG. The substrate 10 is a metal plate with elasticity. Various materials are known for the metal plate, but any material that is heat resistant and elastic may be used, such as heat resistant alloy, steel plate (SS material), etc.
, crack material (SK), stainless steel (SUS), etc. are used. The substrate 10 is formed by known processing means such as punching and laser cutting. The front and back surfaces of the substrate 10 are coated with a primer 11 for the purpose of sufficiently adhering the sealant to the substrate 10.

On the upper layer of the primer 11, a sealant 12 having high gas sealing performance is uniformly coated or bonded, that is, bonded. Therefore, it is desirable that the primer 11 has adhesive properties to both the material of the substrate 1o and the material of the sealant 12. Therefore, the sealant 12, which is not necessarily required for the primer 11, has sealing properties and is excellent in oil resistance, heat resistance, etc. ■Nitrile rubber (NBR), ■Silicone rubber, ■Fluorine rubber It is a material made of one or a mixture of resins such as rubber, ■Teflon resin, and ■fluororesin. Surface pressure agents 13a, 13b, 13c, and 13d are deposited on the sealant 11 on the outer periphery of the cylinder bore 2, oil chamber 5, water hole 3, and other holes.

The blood pressure agent 13a is attached in a circular manner along the outer periphery of the cylinder bore 2. A blood pressure agent 13b is provided on the back surface of the substrate 1o. The blood pressure agent 13b is located on the outer periphery of the surface pressure agent 13a when viewed from the center of the cylinder bore 2. That is, the center position of the surface pressure agent 13a and the center position of the surface pressure agent 13b are at a distance in the radial direction from the cylinder bore 2! The position is shifted by 2. A surface pressure agent 1 is applied to the outer periphery of the metal gasket 1.
3c, a surface pressure agent 13d is applied to the front and back surfaces of the substrate 10 in the same manner as described above. The distance between the two is iIl. The distance between the two is in the relationship l+>lz.

This is due to the following reason. Naturally, the cylinder bore 2 is required to be more airtight than other holes for the operation of the internal combustion engine. Therefore, the surface pressure agent 13a and the surface pressure agent 13b are arranged close to each other. Metal gasket 1 to cylinder 16
When installed between the cylinder head 15 and the cylinder head 15 and tightened with a tightening bolt, the surface of each soft surface pressure agent deforms first (the third
(see figure).

When pressure is applied to the upper part of the blood pressure agent 13a from the joint surface 18 of the cylinder head 15, a downward force acts on the substrate 10, and at the same time, the surface pressure agent 1 is applied from the joint surface 17 side of the cylinder 16.
3b (11), bending stress is generated on the substrate 10. Although the surface pressure agents 13a and 13b have excellent rubber elasticity, the stress applied to the substrate 10 is not concentrated.The bending angle of the substrate 1o is large when the interval is 12, and the interval!
1 is small. That is, in the example of FIG. 3, θ2 is large and θl is small.

A large angle also means that the bending stress generated in the substrate 1o is large. The reaction force of the bending stress acts and reacts between the cylinder head 15 and the cylinder 16, bringing them into close contact with each other, thereby increasing the gas sealing effect. Furthermore, in this embodiment, since a sealant 12 is applied or bonded to the front and back surfaces of the substrate 10, this sealant 12 is applied to the joint surface 18 of the cylinder head 15 and the cylinder 1.
6, the sealing performance is further improved.

Adjustment of blood pressure On the other hand, near the bolt, the blood pressure is strong, and in the part farther from the bolt, the surface pressure is reduced by the amount deformed by the deflection of the cylinder 16 and cylinder head 15. this is,
This is because there is little deflection near the bolts when the cylinder head 15 is tightened. When you leave the bolt,
The deflection between the two becomes larger. In the metal gasket 1, in order to eliminate the above-mentioned surface pressure difference, the distance between the center positions of the front and back surfaces of the double-sided adhesive is set so that the blood pressure is weak near the bolt. In areas farther from the bolt, contact pressure agents 13a, 13b,
Place 13c and 13d.

Further, as described above, it is preferable to reduce the thickness of the surface pressure agent in order to weaken the blood pressure near the bolt, and to increase the height of the surface pressure agent so that the blood pressure becomes stronger at a position farther from the bolt. As mentioned above, in order to make blood pressure uniform, the center positions of the surface pressure agents in the width direction may be adjusted, the thickness of the surface pressure agents may be adjusted, or both may be used in combination. It's okay.

The sealant of this example not only has sealing properties but also can sufficiently absorb machining tool marks on the contact surfaces of the cylinder and cylinder head. Furthermore, in the gasket of this example, since the front and back surfaces of the substrate were coated with a sealant, stress concentration was reduced due to the elasticity of the sealant, and the durability was further improved.

[Second Embodiment] The one shown in Fig. 4 is a second embodiment, in which a metal gasket 2 is provided with slits or punched holes around the bolt holes.
This is an example of 0. The outer periphery of the cylinder bore 21 is provided with a blood pressure agent 2.
2a is for attachment. A blood pressure agent 22b is attached to the metal gasket 20 around the outer periphery of the blood pressure agent 22a and on the back surface thereof. Two slits 24 and two punched holes 23 are provided on the same circumference on the outer periphery of the blood pressure agent 22b.

Further, bolt holes 25 are provided on the outer peripheries of each of the slit 24 and the punched hole 23. In this embodiment, when tightening the bolt, distortion due to pressure is caused by the slit 24 and the punched hole 2.
3 and is difficult to reach around the cylinder bore 21.

[Third Embodiment] FIG. 5 shows an example in which a grommet 32 is covered with a metal gasket 30. The grommet 32 is made of Spiegel (sp
), stainless steel (SUS), copper (Cu), etc. Cylinder bore 31 of metal gasket 30
The parts facing the are exposed to the hot combustion gases. The grommet 32 is equipped with a metal gasket 3 to prevent damage from combustion gas.
This is to prevent zero. Grommet 32 is sealed with sealant 12
is not glued to. The grommet 32 is plate-shaped and is placed only on one surface of the sealant 12, and one end facing the cylinder bore 31 is bent into a U-shape and the bent portion 3
It has 4.

A surface pressure agent 33a is placed on the upper surface of the grommet 32. A surface pressure agent 33b is placed on the upper surface of the sealant 12 on the back side of the surface pressure agent 33a. The grommet 32 is deformed and fixed by tightening the cylinder and cylinder head.

[The fourth embodiment shown in FIG. 6 shows a grommet 42 mounted at a position facing the cylinder bore 41, similar to the third embodiment. The grommets 1 to 42 are provided only in the portion facing the cylinder bore 41, and are annular with a U-shaped cross section. Both blood pressure agents 43a and 43b are sealant 1.
2.12 are arranged at intervals in the same manner as above. The height t2 of the blood pressure medicines 43a and 431-+ is the thickness of the grommet 1-42. Therefore, t2>t.

When the metal gasket 40 is tightened between the cylinder and the cylinder head, the thickness of the plate where the grommet 42 is attached acts as a stopper, and it cannot be tightened any further. On the other hand, the parts near the fastening bolts are exposed to strong blood pressure. It is tightened to the thickness of the primer 11 and sealant 12. Surface pressure agent 43a between the stopper and the bolt
, 4.3b, the inclined tightening is deformed in the gap between the surfaces, and the substrate 1o is bent by the deformed surface pressure agents 43a and 43b. Furthermore, by attaching the grommet 42 to the substrate 1o, the durability of the metal gasket 4o is also improved.

[Fifth Embodiment] FIG. 7 shows a fifth embodiment in which a firing ring 52 is incorporated into the metal gas keratin (50) as described above. The firing ring 52 is made of the same metal as the grommet, and has almost the same function. A firing ring 52 is housed on the side of the metal gasket 50 facing the cylinder bore 51. Blood pressure agents 53a and 53b are arranged in the same manner as described above.

The firing ring 52 also plays a role as a stopper, and this plate thickness is t. is smaller than the height of the surface pressure agents 53a and 53b placed on both sides of the substrate coated with the sealant. Moreover, the step difference on one side becomes t1<t4.

[Sixth Embodiment] FIG. 8 is a cross-sectional view of a metal gasket 60 showing a sixth embodiment, and is an example in which the cross-sectional shape of the surface pressure agents 61a and 61b is not an arc but a triangle. Compared to a blood pressure agent having an arc-shaped cross section, the bending stress applied to the substrate 10 is stronger due to the concentration of force.

[Seventh Example] FIG. 9 shows a metal gasket 70 showing a seventh example. Blood pressure medicines 71:z, 71b, sequentially from the bore 72 to the outer periphery.
A plurality of 71c, 71d, and 71e are arranged. This embodiment is used when the flange has a large diameter and seals high pressure gas. The radial distance between the surface pressure agent 71a and the surface pressure agent 71b from the center of the bore 72! +, blood pressure medicine 71b and blood pressure medicine 71. Radial distance from d! 2. Similarly, the distance ff
! ls, distance! Set it to 4. These distances are l r <
12 <i3ku! There is a relationship of 4. The distance between the surface pressure agents increases toward the outer periphery of the flange. The principle of blood pressure is as described above. This embodiment is optimal when the bolt is located on the outer periphery of the blood pressure agent 71e.

[Eighth Example] FIG. 10 shows an eighth example of the metal gasket 80. A secondary plate 19 is placed on one or both of the blood pressure agents 81a, 81b. In the case of the eighth embodiment, it is used for sealing a flange or the like which is large in thermal deformation and has a long dimension. for example,
Thermal expansion of the flange causes the flange to move. At this time, if there is a possibility that the surface pressure agent may be scraped off due to the roughness of the processed surface of the flange surface, a sub-plate 82 is used on one or both sides of the flange side, which has a large movement, to remove the surface pressure agent 81a.

81b to prevent it from being scraped off.

[Effects of the Invention] As detailed above, the present invention has the following effects.

By coating the front and back of the board with a sealant,
Seal performance has been improved. Since the surface pressure agent is a relatively soft material, it prevents stress concentration, thereby improving the durability of Metal Gaskera 1~.

[Brief explanation of drawings]

Figure 1 is a plan view of the metal gas scaler, Figure 2 is the ■- of Figure 1.
■Cross-sectional view, Figure 3 is a cross-sectional view showing the state in which the cylinder and cylinder head are tightened, Figure 4 is a cross-sectional view showing the second embodiment, Figure 5 is a cross-sectional view showing the third embodiment, Figure 6 is the fifth
7 is a sectional view showing the fifth embodiment, FIG. 8 is a sectional view showing the sixth embodiment, FIG. 9 is a sectional view showing the seventh embodiment, FIG. 10 is a sectional view showing the eighth embodiment. 1.20.30.40,50,60,70.80...
Metal gasket, 2, 21, 31, 41.51... cylinder bore, 10... board, 11... primer 12...
Sealing agent, 34.42...Grommet l-252...
firing ring

Claims (1)

[Claims] 1. A metal gasket comprising a substrate made of a flat metal plate having required holes and having elasticity, and a surface pressure agent provided on the front and back sides of the substrate with their center positions spaced apart from each other, A metal gasket characterized in that the entire front and back surfaces of the substrate are coated with a sealant. 2. The metal gasket according to claim 1, wherein the spacing between the surface pressure agents increases from the center of the hole toward the outside. 3. The metal gasket according to claim 1, wherein a cut portion is provided in the substrate near the bolt and along the outer periphery of the hole. 4. The metal gasket according to claim 1, further comprising a metal grommet provided along the hole to prevent damage to the sealant. 5. The metal gasket according to claim 1, further comprising a sub-plate having a lower hardness than the substrate on at least one side.