JPH08270796A - Gasket - Google Patents

Abstract

PURPOSE: To secure sealing performance at the initial fastening time and secular change time by forming an annular bead protruding on an annular flat part, and deforming the annular bead by plastic forming at the initial fastening time. CONSTITUTION: A seal part 1B is composed of a flat part 2, an annular elastic part 3, an annular flat part 4 and an annular bead 5. The annular elastic part 3 rises inclining from the flat part 2. The annular bead 5 has round cross section and is plastically deformed protruding on the annular flat part 4 in the state of being turned in the direction of being separated from the flat part 2. At the initial fastening time, the annular bead part 5 is hardly deformed plastically because of being already deformed by plastic forming so as to secure sealing performance. When the gasket 1 is secularly changed, fastening force to the gasket 1 is lowered, and the gasket 1 is secularly deformed. When the fastening force is lowered, a clearance between a cylinder head and an intake manifold is enlarged, but since the annular bead 5 is plastically deformed, sealing performance is secured.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a gasket mounted between two parts of an engine.

[0002]

2. Description of the Related Art Conventionally, in order to prevent leakage of intake air and exhaust gas inside an engine between two parts such as a cylinder head of an engine and an intake manifold, as disclosed in, for example, Japanese Utility Model Publication No. 4-8750. Various gaskets are installed.

Known gaskets of this kind are shown in FIGS. 8, 9 and 10, 11. 8 and 9
In the figure, reference numeral 101 is a bead type gasket, and the state before tightening is shown in the drawing. The gasket 101 is fastened between the cylinder head 102 and the intake manifold 103 by bolts and nuts (not shown).
The gasket 101 is made of cold rolled steel plate or stainless steel plate, and the gasket 101 has four windows 101A.
(Only one shown in FIG. 8) is formed. Gasket 101 is placed around each window 101A
One seal portion 101B (only one is shown in FIG. 8).

The seal portion 101B is formed by projecting an annular bead 105 on a flat portion 104. Ring bead 105
Is deformed by plastic forming. When the gasket 101 is tightened, the annular bead 105 is deformed to a rounded cross section by plastic forming, so it is slightly deformed, but it is hard to be plastically deformed and its shape is hard to change before and after tightening. Reserved.

FIGS. 10 and 11 show an elastic deformation type gasket having a structure different from that of the bead type gaskets of FIGS. 8 and 9. In the figure, reference numeral 201 is a gasket, and the state before tightening is shown in the figure. The gasket 201 is fastened between the cylinder head 202 and the intake manifold 203 by bolts and nuts (not shown).

The gasket 201 is made of a cold rolled steel plate or a stainless steel plate, and four windows 201A (only one is shown in FIG. 10) are formed in the gasket 201. The gasket 201 is composed of four seal portions 201B (only one is shown in FIG. 10) arranged around each window 201A. This seal portion 201B is
The flat portion 204, the annular elastic portion 205 that is inclined and rises from the flat portion 204, is located inside the annular elastic portion 205 continuously with the annular elastic portion 205, and is the flat portion 204.
It is composed of an annular flat portion 206 that is floated from above. The elastic force of the annular elastic portion 205 is generated by the bending stress within the elastic limit range of the cold rolled steel plate or the stainless steel plate.

When the gasket 201 is tightened between the cylinder head 202 and the intake manifold 203, the annular elastic portion 205 of the gasket 201 has a function as a spring member with respect to the flat portion 204 and the annular flat portion 206. In the tightened state of the gasket 201, the angle θ2 of the annular elastic portion 205 almost disappears,
The flat portion 2 is formed by the function of the annular elastic portion 205 as a spring material.
04, the annular flat portion 206 is pressed between the cylinder head 202 and the intake manifold 203, and the gasket 201 is compressed and deformed.

Therefore, the gasket 201 covers the entire surface of the cylinder head 202 and the intake manifold 2.
It receives pressure from 03 and is compressed over the entire surface. This provides a sealing function.

[0009]

However, in the bead type gasket 101, when the tightening force decreases due to aging, the clearance δ2 between the cylinder head 102 and the intake manifold 103 widens, but the annular bead is widened. 10
Since No. 5 is plastically deformed, it is hard to be plastically deformed, there is a possibility that the annular bead 105 cannot secure the sealing property because it does not follow the change of the gap δ2.

Further, the elastically deformable gasket 201 has a problem that the sealing property is inferior to that of the bead type gasket 101 at the time of initial tightening. The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a gasket capable of ensuring a sealing property at the time of initial tightening and aging.

[0011]

According to the first aspect of the present invention,
A flat portion, an annular elastic portion that is inclined and risen from the flat portion, an annular flat portion that is located inside the annular elastic portion and that is continuous with the annular elastic portion and that is floating from the flat portion, and an annular flat portion It is characterized in that it is composed of an annular bead protruding upward.

According to a second aspect of the present invention, a flat portion, an annular bead protruding above the flat portion, an annular elastic portion located inside the annular bead and rising from the flat portion at an inclination, and an annular elastic portion. And an annular flat portion that is located inside the annular elastic portion and that floats from the flat portion. The invention according to claim 3 has a flat portion, a first annular bead protruding above the flat portion, and a first annular bead.
An annular elastic portion located inside the annular bead and inclined and rising from the flat portion, and a second annular flat portion that is continuous with the annular elastic portion, is located inside the annular elastic portion, and floats from the flat portion. And an annular bead protruding above the annular flat portion.

[0013]

According to the first aspect of the present invention, the gasket is mounted between the two parts, and when the two parts are tightened, they are deformed by compression and tightened. At the time of initial tightening, the annular bead has already been deformed by plastic forming, so it is difficult to plastically deform, the shape does not change before and after tightening, and sealing performance is secured.

When the gasket is sandwiched between two parts and the two parts are tightened, the annular elastic part of the gasket has a function as a spring member for the flat part and the annular flat part. In the tightened state of the gasket, the angle of the annular elastic portion is almost eliminated. Therefore, the flat portion and the annular flat portion are pressed against each component by the function of the annular elastic portion as the spring material, and the gasket is deformed by compression. The sealing function occurs.

When the gasket is aged, the tightening force on the gasket is reduced and the gasket is permanently deformed. When the tightening force is reduced, the annular bead is plastically deformed, so that it does not follow the change in the gap between the two parts, and the sealing function of the annular bead deteriorates. But,
Since the gasket is subjected to the pressing force over the entire surface by the annular elastic portion, the sealing property is secured.

Further, when the gasket is aged, the seal line is increased by locally contacting two parts at the top of the annular bead, the rising part and the both ends of the annular elastic part to form a seal line. , The deterioration of the sealing function is prevented. In the invention described in claim 2, the same operation as the invention described in claim 1 occurs. In the invention described in claim 3, the same operation as that of the invention described in claim 1 occurs.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5, the gasket according to the embodiment of the invention described in claim 1 will be described with reference to an example in which the gasket is mounted between the cylinder head and the intake manifold. FIG. 1 is a sectional view taken along line XX of FIG. In FIGS. 1 and 4, reference numeral 1 is a gasket, and the gasket 1 is formed with four windows 1A, 1A, 1A, 1A. The gasket 1 is composed of four seal portions 1B, 1B, 1B, 1B arranged around each window 1A.

The seal portion 1B is composed of a flat portion 2, an annular elastic portion 3, an annular flat portion 4 and an annular bead 5. The annular elastic portion 3 is inclined and rises from the flat portion 2. The annular flat portion 4 is located inside the annular elastic portion 3 so as to be continuous with the annular elastic portion 3 and floats from the flat portion 2. The edge 4A of the annular flat portion 4 defines the contour of the rectangular window 1A.

The annular bead 5 has a rounded cross section and is plastically formed on the annular flat portion 4 so as to project in a direction away from the flat portion 2. Then, as shown in FIG. 2, the gasket 1 includes a steel plate 1C and synthetic rubbers 1D, 1 attached to both sides of the steel plate 1C with an adhesive material 6, respectively.
It has a laminated structure composed of D and surface coat layers 1E and 1E attached to the outer surfaces of the synthetic rubbers 1D and 1D, respectively. Examples of the material of the steel sheet 1C include cold rolled steel sheet, stainless steel sheet, spring steel sheet and the like. Synthetic rubber 1D,
1D is to prevent the deterioration of the sealing property. The surface coat layers 1E, 1E are made of resin and prevent the defects caused by the synthetic rubbers 1D, 1D. That is, when the synthetic rubbers 1D and 1D are exposed on the surface, seizure easily occurs, and at the same time, the gasket 1 becomes difficult to slip and is not easily deformed.

As shown in FIG. 3, however, the gasket 1 is sandwiched between the cylinder head 7 and the intake manifold 8, and when the cylinder head 7 and the intake manifold 8 are tightened with bolts and nuts (not shown), the result shown in FIG. It becomes the state shown. In FIG. 5, at the time of initial tightening, the annular bead 5 has already been deformed by plastic forming, so it is difficult to plastically deform, the shape does not change before and after tightening, and the sealing property is secured.

The elastic force of the annular elastic portion 3 of the gasket 1 is generated by a bending stress within the elastic limit range of a cold rolled steel plate, a stainless steel plate, a spring steel plate or the like.
The annular elastic portion 3 functions as a spring material for the flat portion 2 and the annular flat portion 4. In the tightened state of the gasket 1, the angle θ1 of the annular elastic portion 3 almost disappears. Therefore, the flat portion 2, the annular flat portion 4 become the cylinder head 7 and the intake manifold 8 due to the function of the annular elastic portion 3 as a spring material. When pressed, the gasket 1 is compressed and deformed, and a sealing function occurs.

When the gasket 1 is aged, the tightening force on the gasket 1 is reduced and the gasket 1 is permanently deformed. When the tightening force drops, the gap δ1 between the cylinder head 7 and the intake manifold 8 widens, but the annular bead 5 is plastically deformed, so it does not follow the changes in the gap δ1 and the sealing function of the annular bead 5 is reduced. Will fall. However, due to the elastic force of the annular elastic portion 3, the gasket 1
Since the pressing force is applied over the entire surface, the sealing property is secured.

Further, as shown in FIG. 5, when the gasket 1 changes with time, the intake manifold 8 is locally provided at the top 5A of the annular bead 5 and one end 3A of the annular elastic portion 3.
The seal lines S1 and S2 are formed in contact with. Further, the gasket 1 locally contacts the cylinder head 7 at the rising portions 5B, 5C of the annular bead 5 and the other end 3B of the annular elastic portion 3 to form the seal lines S3, S4, S5. In this way, the seal lines S1, S2, S3, which have high local pressure,
Since there are S4 and S5, deterioration of the sealing function is prevented.

Further, in this embodiment, the plate thickness of the steel plate 1C is set in the range of 0.15 to 0.50 mm, the inclination angle θ1 of the annular elastic portion 3 is set in the range of 10 to 30 degrees, and the flat portion 2 is formed. The height dimension H1 from the upper surface 2A to the upper surface 4B of the annular flat portion 4 is set in the range of 0.1 to 0.3 mm, and the annular bead 5
Inlet leakage was measured by setting the height dimension H2 of the above to a range of 0.1 to 0.3 mm and setting the bending radius of the annular bead 5 to a range of 0.3 to 1 mm. At the same time, the leakage of the intake air was measured for the annular bead 105 of the bead type gasket 101 of the conventional example and the annular elastic portion 205 of the elastically deformable gasket 201 under the same conditions as those of this example. It was confirmed that the leakage of intake air in this example is less than the leakage of intake air in the conventional example.

In this way, the gasket 1 prevents the intake air flowing through the intake passage 9 from leaking to the outside from between the cylinder head 7 and the intake manifold 8. According to the above configuration, the gasket 1 has the annular bead 5 already deformed by plastic forming. Therefore, at the time of initial tightening, the annular bead 5 is less likely to be plastically deformed and its rounded cross-section is tightened. The sealing property can be secured by the annular bead 5, which does not change before and after.

Further, when the tightening force is reduced, the gasket 1 is pressed against the entire surface by the elastic force of the annular elastic portion 3, so that the sealing property can be secured. Furthermore, when the secular change occurs, the gasket 1 is attached to the top portion 5 of the annular bead 5.
A, rising portions 5B, 5C and both ends 3A of the annular elastic portion 3,
Since 3B locally contacts the two parts of the cylinder head 7 and the intake manifold 8, the seal lines S1, S2, S3, S4, S5 having high local pressure are formed, and the seal lines are more sealed than the conventional gasket. It is possible to prevent the deterioration of the sealing function by increasing the number of lines.

In this embodiment, the gasket 1
Although the above description has been given by taking the example of being mounted between the cylinder head 7 and the intake manifold 8, the present invention is not limited to such a portion, and for example, a gasket may be provided between the cylinder head and the exhaust manifold and between the cylinder block and the front gear case. You can also wear. Also,
In this embodiment, the annular elastic portion has one step, but it may have a plurality of steps.

Further, in this embodiment, the number of the annular beads is one, but it may be plural. In addition, although the window 1A has a square shape in the present embodiment, the shape is not limited to such a shape, and may have various shapes such as a circular shape, an oval shape, and an elliptical shape.

An example in which the gasket according to the embodiment of the invention described in claim 2 is mounted between the cylinder head and the intake manifold will be described with reference to FIG. In the drawings, reference numeral 21 is a gasket, and the plane shape thereof is defined by claim 1.
Similar to the gasket according to the embodiment of the described invention,
The gasket 21 is formed with four square windows 21A (corresponding to the window 1A in FIG. 4). Gasket 21
Consists of four seals 21B arranged around each window 21A.

The seal portion 21B is composed of a flat portion 22, an annular bead 23, an annular elastic portion 24, and an annular flat portion 25. The annular bead 23 has a rounded cross section, and is projected on the flat portion 22 in a direction away from the annular flat portion 25. The annular elastic portion 24 is located inside the annular bead 23 and rises while being inclined from the flat portion 22.

The annular flat portion 25 is located inside the annular elastic portion 24 so as to be continuous with the annular elastic portion 24. According to this embodiment, the same action and effect as those of the embodiment shown in FIG. 1 are produced. That is, at the time of initial tightening, the sealing performance can be secured by the annular bead 23, and when the tightening force drops, the sealing performance can be secured by the annular elastic portion 24, and the number of sealing wires is increased as compared with the conventional gasket. It is possible to prevent deterioration of the sealing function.

In this embodiment, the gasket 2
1 has been described as an example of being mounted between the cylinder head and the intake manifold, but the present invention is not limited to such a portion, and for example, a gasket may be provided between the cylinder head and the exhaust manifold and between the cylinder block and the front gear case. You can also wear it. Further, in this embodiment, the annular elastic portion has one step,
There can be multiple stages.

Further, in the present embodiment, the number of annular beads is one, but it is also possible to make a plurality. Further, in the present embodiment, the window 21A has a square shape, but it is not limited to such a shape, and may have various shapes such as a circular shape, an oval shape, and an elliptical shape.

An example in which the gasket according to the embodiment of the invention described in claim 3 is mounted between the cylinder head and the intake manifold will be described with reference to FIG. In the drawings, reference numeral 31 is a gasket, and the plane shape thereof is defined by claim 1.
Similar to the gasket according to the embodiment of the described invention,
The gasket 31 is formed with four rectangular windows 31A (corresponding to the window 1A in FIG. 4). Gasket 31
Is a seal part 31 arranged around each window 31A.
It consists of B.

The seal portion 31B includes a flat portion 32, a first annular bead 33, an annular elastic portion 34, and an annular flat portion 3.
5 and a second annular bead 36. First
The annular bead 33 has a rounded cross section and is projected on the flat portion 32 in a direction away from the annular flat portion 35. The annular elastic portion 34 is located inside the first annular bead 33 and is inclined and rises from the flat portion 32.

The annular flat portion 35 is located inside the annular elastic portion 34 so as to be continuous with the annular elastic portion 34. The second annular bead 36 has a rounded cross section, and is plastically formed on the annular flat portion 35 so as to project in a direction away from the flat portion 32. According to this embodiment, the same action and effect as those of the embodiment shown in FIG. 1 are produced. That is, at the time of initial tightening,
The first annular bead 33 and the second annular bead 36 can ensure the sealing property, and when the tightening force is reduced, the annular elastic part 34 can ensure the sealing property. Further, the number of sealing wires is larger than that of the conventional gasket. It is possible to prevent the deterioration of the sealing function.

In this embodiment, the gasket 3
1 has been described as an example of being mounted between the cylinder head and the intake manifold, but the present invention is not limited to such a portion, and for example, a gasket may be provided between the cylinder head and the exhaust manifold and between the cylinder block and the front gear case. You can also wear it. Further, in this embodiment, the annular elastic portion has one step,
There can be multiple stages.

Further, in this embodiment, the first and second
The number of annular beads is one, but it is also possible to make a plurality. Further, in the present embodiment, the window 31A has a square shape, but the shape is not limited to such a shape, and may have various shapes such as a circular shape, an oval shape, and an elliptical shape.

[0039]

According to the first aspect of the present invention, at the time of initial tightening, the gasket has the annular bead already deformed by plastic forming, so that the sealing performance can be secured. Further, when the tightening force decreases due to aging, the gasket is subjected to the pressing force over the entire surface by the annular elastic portion, so that the sealing property can be secured.

Further, when the gasket is aged, the gasket forms a seal line by locally contacting two parts at the top of the annular bead, the rising part, and both ends of the annular elastic part, so that the number of seal lines increases. It is possible to prevent deterioration of the sealing function.
According to the invention of claim 2, the same effect as that of the invention of claim 1 can be obtained. According to the invention of claim 3, the same effect as that of the invention of claim 1 can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing a gasket according to an embodiment of the invention described in claim 1.

FIG. 2 is an explanatory view showing a laminated structure of the gasket.

FIG. 3 is an explanatory cross-sectional view of an attached state of the gasket before tightening.

FIG. 4 is a plan view of the gasket.

FIG. 5 is an explanatory cross-sectional view of the gasket in a tightened state.

FIG. 6 is a sectional view of an essential part showing a gasket according to an embodiment of the invention as set forth in claim 2;

FIG. 7 is a sectional view of an essential part showing a gasket according to an embodiment of the invention as set forth in claim 3;

FIG. 8 is a plan view showing a conventional bead type gasket.

9 is a cross-sectional view taken along line YY of FIG.

FIG. 10 is a plan view showing a conventional elastically deformable gasket.

11 is a cross-sectional view taken along line ZZ of FIG.

[Explanation of symbols]

 1 Gasket 2 Flat Part 3 Annular Elastic Part 4 Annular Flat Part 5 Annular Bead

Claims (3)

[Claims] 1. A flat portion, an annular elastic portion which is inclined and risen from the flat portion, an annular flat portion which is located inside the annular elastic portion and which is continuous with the annular elastic portion, and which floats from the flat portion. And a ring-shaped bead protruding above the ring-shaped flat portion. 2. A flat portion, an annular bead protruding above the flat portion, an annular elastic portion located inside the annular bead and rising from the flat portion at an inclination, and the annular elastic portion being continuous with the annular elastic portion. A gasket comprising an annular flat portion located inside the elastic portion and floating above the flat portion. 3. A flat portion, a first annular bead protruding above the flat portion, an annular elastic portion that is located inside the first annular bead and is inclined and raised from the flat portion, and is continuous with the annular elastic portion. And a second annular flat portion located inside the annular elastic portion and floating from the flat portion, and an annular bead protruding above the annular flat portion.