JP6782091B2 - gasket - Google Patents

Description

The present invention relates to a gasket, and more particularly to a gasket, which can secure a follow-up amount of beads to the mating surface to improve the sealing surface pressure and suppress distortion of the gasket due to heat without increasing the weight of the gasket.

Generally, gaskets used in internal combustion engines need to seal hot fluids. For example, an exhaust manifold gasket that seals exhaust gas at several hundred degrees Celsius is provided between the cylinder head of an engine of an automobile or the like and the exhaust manifold.

The seal gasket that seals such a high-temperature fluid is formed of a metal plate such as a spring steel plate having heat resistance, and the bead formed on the metal plate is compressed between the mating surfaces at the time of tightening to form a predetermined seal. It is designed to generate surface pressure.

In recent years, the weight of the engine has been reduced, and the rigidity of the mating surface that compresses the gasket tends to decrease. As a result, the amount of compression of the bead at the time of tightening cannot be sufficiently secured, and the amount of the bead following the mating surface may be insufficient, so that the sealing surface pressure may decrease.

Conventionally, for the purpose of securing the follow-up amount of beads and increasing the sealing surface pressure, a laminated gasket in which a plurality of metal plates each having half beads are laminated may be used. However, increasing the number of laminated metal plates leads to an increase in the weight of the gasket, which goes against the trend of weight reduction in recent years.

Further, in Patent Document 1, a grommet formed by folding back a metal plate different from the gasket is provided on the peripheral portion of the bore hole of the gasket, and an auxiliary plate is provided on the flat portion between the peripheral portion of the bore hole and the bead. , A metal gasket designed to ensure the springiness of the bead for a long period of time is disclosed. However, this gasket is intended to prevent the bead from being exposed to high temperature and high pressure flames, and does not increase the sealing surface pressure by providing a grommet or a sub plate. Moreover, since separate members such as grommets and sub-plates are added to the gasket, it also goes against the trend of weight reduction.

On the other hand, in Patent Document 2, the gasket is composed of a plate of the peripheral portion of the cylinder bore and a plate of the remaining part of the gasket excluding the peripheral portion of the cylinder bore, and the plate of the remaining gasket is thinner and more advanced than the plate of the peripheral portion of the cylinder bore. A cylinder head gasket formed of a high metal plate, fitted with these, and laser-welded with the fitting portion is disclosed.

According to this gasket, when tightened by the mating surface, the surface pressure is concentrated on the peripheral portion of the thick cylinder bore, so that the sealing surface pressure can be expected to be improved. Moreover, since it is not necessary to add a separate member, the weight of the gasket does not increase.

Jikkenhei 02-6855 Japanese Unexamined Patent Publication No. 8-285080

However, if there is a difference in the thickness of the plates constituting the gasket, distortion may occur in the thin plate when the plate expands due to the heat of the fluid or the like to be sealed. This is because a tightening load is not applied to a thin plate.

In the gasket described in Patent Document 2, since the fitted plates are completely integrated by laser welding, the distortion of the thin plate is transmitted to the thick plate, which affects the sealing performance of the thick plate. May be given. This effect becomes more pronounced as the rigidity of the mating surface is lower.

Therefore, it is an object of the present invention to provide a gasket that can secure the amount of beads that follow the mating surface, improve the sealing surface pressure, and suppress the distortion of the gasket due to heat, without increasing the weight of the gasket. To do.

Other problems of the present invention will be clarified by the following description.

The above problems are solved by the following inventions.

1. 1.
A bead portion plate having a bore hole and a bead formed so as to surround the bore hole, and an outer peripheral plate arranged so as to surround the bead portion plate are provided.
The plate thickness of the bead portion plate is thicker than the plate thickness of the outer peripheral plate.
A gasket characterized in that the outer peripheral plate is joined to the bead portion plate at a joint portion and is provided so as to be displaceable in the thickness direction with the joint portion as a fulcrum.
2.
The gasket according to 1 above, wherein a gap is provided between the bead portion plate and the outer peripheral plate.
3. 3.
The gasket according to 1 or 2 above, wherein the joint is formed in a dot shape.
4.
The gasket according to 1, 2 or 3, wherein the joint portion is arranged at a central portion in the length direction of the bead portion plate.

According to the present invention, it is possible to provide a gasket capable of ensuring the amount of beads following the mating surface to improve the sealing surface pressure and suppressing distortion of the gasket due to heat without increasing the weight of the gasket.

Top view showing one embodiment of the gasket according to the present invention. Top view showing the gasket shown in FIG. 1 in an exploded manner. Enlarged end view along the (iii)-(iii) line in FIG. Enlarged end view along the (iv)-(iv) line in FIG. The end view showing the state in which the gasket shown in FIG. 1 is tightened between the mating surfaces is cut at the same portion as the line (iii)-(iii) in FIG. Top view showing another embodiment of the gasket according to the present invention. Enlarged end view along the (vii)-(vii) line in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view showing an embodiment of the gasket according to the present invention, FIG. 2 is a plan view showing the gasket shown in FIG. 1 in an exploded manner, and FIG. 3 is (iii)-(iii) in FIG. An enlarged end view along the line, FIG. 4 is an enlarged end view along the (iv)-(iv) line in FIG.

In this embodiment, the exhaust manifold gasket is illustrated as the gasket 1. The exhaust manifold gasket is a gasket that is sandwiched between the cylinder head and the exhaust manifold and seals the high-temperature exhaust gas discharged from the cylinder head side.

The gasket 1 is configured to include two plates, a bead portion plate 2 and an outer peripheral plate 3. The bead portion plate 2 is made of a metal plate suitable for sealing high-temperature exhaust gas such as a stainless spring steel plate or a heat-resistant spring steel plate. The bead portion plate 2 has a bore hole 21 and a bead 22.

The bore hole 21 is circularly opened so as to communicate with the exhaust gas discharge port of the cylinder head. The bead portion plate 2 shown in the present embodiment has two bore holes 21 corresponding to the flow paths of the two exhaust gas systems, and is formed in a cocoon shape as a whole. However, in the present invention, the shape and number of the bore holes 21 are not limited to those shown, and the outer shape of the bead portion plate 2 is not limited to those shown.

The bead 22 is formed in an annular shape so as to individually surround each bore hole 21. The bead 22 is a half bead as shown in FIG. 3, but may be a full bead.

The outer peripheral plate 3 has one cocoon-shaped opening 31 corresponding to the bead portion plate 2 in the central portion. The opening 31 has a size that can substantially surround the outer circumference of the bead portion plate 2. Further, an appropriate number of bolt holes 33 for inserting fastening bolts are formed on the outside of the opening 31.

In the opening 31 of the outer peripheral plate 3, two joining projecting piece portions 32 are formed at a portion corresponding between the two bore holes 21 of the bead portion plate 2. These joining projecting piece portions 32 project in a mountain shape so that the inner peripheral edge portions facing each other are close to each other in the central portion in the length direction (left-right direction of FIGS. 1 and 2) of the opening portion 31. It is formed.

The bead portion plate 2 and the outer peripheral plate 3 are overlapped at these two joining projecting piece portions 32, and are joined and integrated. Reference numerals 34 in FIGS. 1 and 4 indicate two joints between the bead portion plate 2 and the outer peripheral plate 3. The joint portion 34 is arranged at a line target position with respect to the long axis A (see FIG. 2) passing through the center of the bead portion plate 2.

As shown in FIG. 3, the gasket 1 has a bead portion plate 2 having a thickness T1 thicker than the outer peripheral plate 3 having a thickness T2 (T1> T2). Therefore, as shown in FIG. 5, when the gasket 1 is tightened between the end face 100a of the cylinder head 100 and the end face 200a of the exhaust manifold 200, the thick bead portion plate 2 is attached to both end faces 100a and 200a. It comes into contact and is sandwiched between them. As a result, the contact area with the end faces 100a and 200a with respect to the total area of the gasket 1 becomes small, and the tightening load is concentrated on the bead portion plate 2.

Here, since "surface pressure = load / contact area", the surface pressure increases as the contact area decreases. Therefore, according to this gasket 1, the surface pressure is increased by concentrating the tightening load on the bead portion plate 2, and the sealing surface pressure by the bead 22 formed on the bead portion plate 2 is improved. Therefore, it is possible to sufficiently secure the amount of the bead 22 to follow the end faces 100a and 200a. Since it is not necessary to add a separate member in order to improve the sealing surface pressure, the weight does not increase.

If the outer peripheral plate 3 is formed thinner than the bead portion plate 2, the gasket 1 can be made lighter than a gasket having the same shape as the whole bead portion plate 2. Further, there is also an effect that the sealing surface pressure can be finely adjusted without changing the shape of the entire gasket 1 only by adjusting the area and the plate thickness of the bead portion plate 2.

Further, since the outer peripheral plate 3 only needs to perform the functions of positioning the bead portion plate 2 and positioning the gasket 1 at the mounting portion, the outer peripheral plate 3 can be formed of a material that is cheaper than the bead portion plate 2. As a result, the cost of the gasket 1 can be easily reduced.

As shown in FIG. 1, the bead portion plate 2 is joined by overlapping the outer peripheral plate 3 at the joining projecting piece portion 32 when the gasket 1 is viewed in a plan view. However, when the gasket 1 is viewed in a plan view, most of the bead portion plate 2 is arranged so as to fit inside the opening 31 of the outer peripheral plate 3 except for the overlapping portion in the joining projecting piece portion 32, and the gasket 1 is arranged with the outer peripheral plate 3. Are not joined at all. Therefore, the outer peripheral plate 3 is provided so as to be displaceable with respect to the bead portion plate 2 in the thickness direction (vertical direction with respect to the paper surface in FIG. 1 and vertical direction in FIG. 3) with the joint portion 34 as a fulcrum.

As described above, the outer peripheral plate 3 to which the tightening load due to the end faces 100a and 200a is not applied can be displaced in the thickness direction with respect to the bead portion plate 2, so that when the outer peripheral plate 3 is distorted by heat, the outer peripheral plate 3 is displaced. 3 bends and deforms independently of the bead portion plate 2. As a result, the influence of the distortion of the outer peripheral plate 3 on the bead portion plate 2 can be significantly suppressed. Therefore, the distortion of the entire gasket 1 due to heat can be suppressed, and the initial sealing performance of the bead portion plate 2 can be maintained for a long period of time.

A gap S is formed between the bead portion plate 2 and the outer peripheral plate 3, specifically, between the outer peripheral end surface 2a of the bead portion plate 2 and the inner peripheral end surface 3a of the outer peripheral plate 3 when the gasket 1 is viewed in a plan view. It is preferable to provide. Since the gap S can avoid interference between the bead portion plate 2 and the outer peripheral plate 3, the influence of the distortion of the outer peripheral plate 3 on the bead portion plate 2 can be more effectively suppressed. Further, the gap S also has an effect of absorbing a dimensional error between the bead portion plate 2 and the outer peripheral plate 3.

The gap S is formed at the center of the bore hole 21 from the overlapping portion of one joining projecting piece portion 32 between the bead portion plate 2 and the outer peripheral plate 3 from the viewpoint of avoiding interference between the bead portion plate 2 and the outer peripheral plate 3 as much as possible. It is preferably formed over a region of 180 ° or more on the outer periphery of the bead portion plate 2 as the center, and more preferably formed over a region of 250 ° or more. More preferably, as shown in FIG. 1, a gap S is provided over the entire area from the overlapping portion in one joining projecting piece portion 32 to the overlapping portion in the other joining projecting piece portion 32.

Further, the gap S preferably includes at least the regions at both ends of the bead portion plate 2 in the length direction (left-right direction in FIGS. 1 and 3). Even if the outer peripheral plate 3 is stretched in the length direction due to thermal expansion, the stretch can be absorbed by the gap S, so that the influence of the stretch due to thermal expansion of the gasket 1 can be suppressed.

In the present invention, the joint portion 34 is preferably formed in a dot shape. Since the joint area between the bead portion plate 2 and the outer peripheral plate 3 can be reduced, the influence of distortion and elongation of the outer peripheral plate 3 on the bead portion plate 2 via the joint portion 34 can be suppressed to a small extent.

The joint portion 34 shown in FIG. 4 shows an example in which the bead portion plate 2 and the outer peripheral plate 3 are formed in a dot shape by spot welding at the overlapping portion of the joining protrusion portion 32. In addition, the dot-shaped joint portion 34 may be formed by, for example, eyelets or rivets.

As shown in FIG. 1, when the joint portion 34 is arranged at the central portion in the length direction of the bead portion plate 2, the bead portion plate 2 can be stably joined and held with respect to the outer peripheral plate 3. it can. Further, even if the outer peripheral plate 3 is distorted, both sides of the joint portion 34 can be displaced symmetrically with respect to the bead portion plate 2, so that the influence of the strain on the bead portion plate 2 is further increased. It can be made smaller.

The gasket 1 according to the present invention is not limited to the one in which the bead portion plate 2 and the outer peripheral plate 3 are overlapped and joined, but the bead portion plate 2 and the outer peripheral plate 3 are butted against each other and joined at the abutting portion. You may.

FIG. 6 is a plan view showing an embodiment of such a gasket 1, and FIG. 7 is an enlarged end view taken along the (vii)-(vii) line in FIG.

In the gasket 1 shown in FIGS. 6 and 7, the bead portion plate 2 and the outer peripheral plate 3 are not overlapped in the joining projecting piece portion 32 formed on the outer peripheral plate 3, and the entire bead portion plate 2 is the outer circumference. It is arranged so as to fit completely into the opening 31 of the plate 3.

The joining projecting piece portion 32 of the outer peripheral plate 3 protrudes toward the bead portion plate 2 fitted in the opening 31, and is in contact with the bead portion plate 2. That is, the outer peripheral end surface 2a of the bead portion plate 2 and the inner peripheral end surface 3a of the outer peripheral plate 3 are abutted at the portion of the joining projecting piece portion 32. A gap S is provided between the bead portion plate 2 and the outer peripheral plate 3 over the entire region other than the abutting portion.

The joint portion 34 is formed over the abutting portion between the bead portion plate 2 and the outer peripheral plate 3. Such a joint portion 34 can be formed by, for example, laser welding, brazing, soldering, or the like.

By forming the joint portion 34 at the abutting portion between the bead portion plate 2 and the outer peripheral plate 3 in this way, the thickness of the gasket 1 is partially increased as in the case where the bead portion plate 2 and the outer peripheral plate 3 are overlapped with each other. It doesn't get thick.

The gasket according to the present invention is not limited to the exhaust manifold gasket described above, and can be widely applied to applications for sealing high-temperature fluids. However, unlike the cylinder head gasket, the exhaust manifold gasket is not cooled by the cooling water and comes into direct contact with the exhaust gas having a high temperature of several hundred degrees Celsius, so that it is strongly affected by the heat. Therefore, according to the exhaust manifold gasket, the above-mentioned effect of suppressing the distortion of the gasket due to heat can be remarkably obtained, which is a preferable embodiment in the present invention.

1: Gasket 2: Bead plate 2a: Outer peripheral end surface 21: Bore hole 22: Bead 3: Outer plate 3a: Inner peripheral end surface 31: Opening 32: Joint projecting piece 33: Bolt hole 34: Joint

Claims (4)

A bead portion plate having a bore hole and a bead formed so as to surround the bore hole, and an outer peripheral plate arranged so as to surround the bead portion plate are provided.
The thickness Ikoto than the thickness of the thickness of the bead plate is the outer peripheral plate, when tightened by the other member from a thickness direction, the outer peripheral plate in the tightening load is not Kakekara, the bead plate Tightening load is applied,
A gasket characterized in that the outer peripheral plate is joined to the bead portion plate at a joint portion and is provided so as to be displaceable in the thickness direction with the joint portion as a fulcrum. The gasket according to claim 1, wherein a gap is provided between the bead portion plate and the outer peripheral plate. The gasket according to claim 1 or 2, wherein the joint is formed in a dot shape. Two of the bore holes are formed in the bead portion plate.
The gasket according to claim 1, 2 or 3, wherein the joint portion is arranged at a central portion in a direction in which the two bore holes are aligned .

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