JPH01153872A - Metal gasket - Google Patents

Abstract

PURPOSE:To simplify manufacture and ensure complete sealing with a small face pressure in a gasket in which a defined hole is opened by providing face- pressure agents leaving a distance between the center positions in the width direction of the face-pressure agents on each side of the gasket. CONSTITUTION:The coating thickness (h) of sealing agents A, B from the surface of a gasket 1 is varied depending on the outer peripheral position thereof. The reaction forces from the contacting points 12, 13 of the sealing agents A, B push the gasket 1 deforming the gasket 1 from a flat face to a curved face against the resilient force of the gasket 1. Since the gasket 1 is made of a metal plate having a spring rigidity, reaction force is generated against the deformation. This reaction force causes action/reaction between a cylinder head and a cylinder to closely seal both. Thereby, complete sealing can be ensured with a small face pressure while simplifying manufacture.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial 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 conventional engine cylinder rad gaskets and turbocharger gas-liquid sealing gaskets. In particular, engine cylinder head gaskets are required to have higher sealing performance due to the demand for smaller and lighter engines. As something that satisfies this performance,
Metal gaskets are being used.

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, and by applying pressure from both sides of the bead portion, the bead portion is deformed to improve sealing performance. are listed.

Japanese Utility Model Application No. 60-18247 discloses a gasket made of an iron plate, in which an uneven bead portion surrounding a water hole, that is, an annular groove, is formed on both sides of the gasket, and this annular groove is coated with a sealant made of silicone resin. Are listed.

[Problems to be Solved by the Invention] The gas get described in the above-mentioned Japanese Utility Model Publication No. 57-59952 improves the sealing performance, but when the gas get is tightened from both sides, the bead portion deforms and becomes flat. At that time, stress is concentrated at the corners of the bead. For this reason, when used for a long period of time, the parts where stress is concentrated 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,
Metal Mi undergoes work hardening and work strain due to bending.
becomes structurally weaker. It is also necessary to prepare a press mold for processing.

For the same reason as described above, the method described in Japanese Utility Model Application Publication No. 60-18247 also requires a bending process to form the bead portion. Further, this gasket is a gasket for a water hole, and there is no concept of sealing a cylinder hole that is exposed to high-temperature flame heat.

In the above-mentioned conventional technology, 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. The present invention solves the above problems.

An object of the present invention is to provide a gasket which is simple in construction and does not cause stress concentration even when the gas get is tightened.

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

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

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

The gasket is a flat metal plate with required holes, characterized in that surface pressure agents are provided on the front and back sides of the gasket with center positions in the width direction of the surface pressure agents spaced apart from each other. It is a metal gasket.

[Operation of the invention] A flat gasket is placed between the two members to be sealed. When both 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 pushed toward the double-sided pressure side and deformed into a wave shape, while being tightened and fixed.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

A gasket 1 shown in FIG. 1 is a gasket for an automobile engine according to the present invention, and is interposed between a cylinder head. In this example, there are four cylinder holes 2. Bolt six 3. Water hole 4. It has an oil container 5, etc. The cylinder hole 2 corresponds to the combustion chamber of the engine. Bolt 63 is a bolt for fixing the cylinder and cylinder head. The water hole 4 is for passing cooling water for cooling the engine. The oil container 5 is for passing lubricating oil for lubrication.

FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1. gasket 1
A sealant A having a diameter DI is attached to the outer periphery of the cylinder hole 2. The sealant A is applied in a mountain-like cross section. A known material such as silicone resin is used as the material, and a sealant B having a diameter D2 is attached to the back surface opposite to the surface to which the sealant A is attached at the inner peripheral position and is compatible with the sealant A. Although the sealants A and B of this embodiment have sealing properties, sealing properties are not necessarily required, and as will be described later, any surface pressure material that generates surface pressure may be used. Sealing performance is ensured on the opposite side of the surface pressure agent.

The coating thickness h of the sealants A and B from the surface of the gasket 1 is varied depending on the position on the outer periphery. This is because when the cylinder head and cylinder are tightened with bolts, the gap between them differs depending on the outer circumferential position, as described above. Around the bolt, the tightening force is strong and the gap becomes small, and the farther away it is, the larger the gap becomes. Since the tightening pressure of the bolts of the cylinder head is predefined in design, the gap can be measured.

The thickness h of the sealants A and B is adjusted according to this gap and changed according to the outer peripheral position. However, if strictness is not required, the same thickness may be used. Figure 3(a) shows the starting point of tightening the cylinder head and cylinder, Figure 3(b)
3(c) shows the state in the middle, and FIG. 3(c) shows the state after tightening. Contact points 12, 13 of the sealants A, H are created which push the gasket 1 and deform it from a flat plate into a curved surface against the elastic force of the gasket 1.

Since the gasket 1 is made of a metal plate, a reaction force is generated to resist this deformation. This reaction force causes an action and a reaction between the cylinder head and the cylinder, sealing the two. The thickness of the sealants A and B is also determined according to the reaction force of this tightening force, so that uniform tightening can be achieved.

[Other Embodiments] In the embodiment shown in FIG. 4, a fire guard 11 is provided on one side of the gasket in contact with the combustion chamber in order to protect the gasket 1 from flames in the combustion chamber. The fire guard 11 is made of known materials such as plating, thermal spraying, and metal plate attachment, which have excellent high-temperature resistance. fire guard 1
There is a height of Δh between the sealant B and the sealant B. Δh acts as a tightening margin. In the example shown in FIG. 5, fire guards are provided on both sides. In the example shown in Fig. 6, a fire guard 1 is placed in the middle of the gasket 1 in the thickness direction.
1 was inserted.

In the embodiment described above, seals A,
B is applied to the outer periphery of the cylinder hole 2 so as to correspond to the cylinder hole 2. As described above, insert the bolt into the bolt 63 and tighten the cylinder and cylinder head. The tightening force between the cylinder and cylinder head is stronger around the bolt and becomes weaker as it gets farther from the bolt. this is,
This is because the cylinder and cylinder head bend. The amount of deflection is determined by determining the tightening pressure of the bolt.

In the embodiment shown in FIG. 7, the distance in the radial direction of the cylinder hole 2 between the sealant A and the sealant B is changed in accordance with the change in the amount of deflection. It is 11 at a position farther from bolt 63, and 12 at a position closer to it. The position of sealant A was changed so that f+ <12. In this example, the position of the sealant B is in a circle corresponding to the cylinder hole 2. However, sealant A is provided in a circular shape, and sealant B near cylinder hole 2.
The distance between the sealant A and the sealant A may be changed. Furthermore, if the distance cannot be maintained, the thickness of the sealant may be changed.

The example shown in FIG. 8 is an example in which the upper and lower parts of the gasket are sandwiched between soft steel plates 20. The soft steel plate 20 is the cylinder head,
Cylinder tool mark (cutting).

It bites into the roughness of the grinding tool trajectory. Therefore, even if the cylinder or cylinder head expands or contracts due to heat, the sealants A and B will not be cut or scraped off by the tool marks and will not be deformed. Furthermore, the effect can be further enhanced by applying or pasting a thin layer of a soft sealant, rubber, resin, etc. on the surface or both surfaces of the soft steel plate that will come into contact with the engine. The same can be said of the single gasket 1 described above that is not provided with a soft steel plate.

The present invention applies not only to engine cylinder gaskets, but also to
It can also be applied to flange joints and cylinder heads of near compressors.

[Effects of the Invention] As detailed above, in the present invention, the sealant is applied to both sides of a flat gasket at offset positions, so it is easy to manufacture without impairing the sealing effect, and it can be manufactured in the same way as a conventional gasket. We were able to provide a gasket that does not cause stress concentration.

[Brief explanation of the drawing]

Figure 1 is an overall view of the gasket, Figure 2 is ■-■ of Figure 1.
3(a), (b), and (c) are diagrams showing the deformation process due to the clamping action of the gasket; FIG. 4 is a diagram showing another embodiment provided with a fire guard; FIG. 5 is a diagram showing another embodiment in which a fire guard is provided, FIG. 6 is a diagram showing another embodiment in which a fire guard is provided, and FIG. 7 is a diagram showing an embodiment in which the gap between the sealants is changed, 8th
The figure is a diagram showing an example of use of the present invention. 1...Gasket, 2...Cylinder hole, A=B...
・Sealant, 11...Fire guard

Claims (1)

[Scope of Claims] 1. In a gasket that is a flat metal plate and has required holes, a surface pressure agent is placed on the front and back sides of the gasket with the centers of the surface pressure agents spaced apart from each other in the width direction. A metal gasket characterized by being provided with. 2. A metal gasket according to claim 1, characterized in that the thickness of the surface pressure agent is varied so that the reaction force of the tightening pressure of the gasket is uniform. 3. According to claim 1, the distance between the surface pressure agents on the front and back sides of the gasket is varied depending on the tightening position so that the reaction force of the tightening pressure of the gasket is uniform. metal gasket. 4. A metal gasket according to claim 1, characterized in that a soft plate material is interposed on the front and back surfaces of the gasket.