JP4541399B2 - Metal gasket - Google Patents

Description

  The present invention relates to a metal gasket that is sandwiched between two members such as an engine cylinder head and a cylinder block for sealing, and more specifically, the pressure of a fluid to be sealed can be used as a seal surface pressure. The present invention relates to a metal gasket that can exhibit excellent sealing performance.

  Metal gaskets such as cylinder head gaskets are fastened with bolts in a state of being sandwiched between two engine members such as a cylinder head of an automobile engine and a cylinder block (cylinder body), and combustion gas, oil, cooling water It has a role to seal fluid such as.

  Recent engines are becoming smaller and lighter than conventional engines, and the material changes from cast iron to aluminum alloy, and the combustion gas pressure tends to increase as the engine output increases. . On the other hand, from the viewpoint of reducing the weight of the engine, the number of metal component plates that can be used for the gasket is decreasing, and it is necessary to exhibit a high seal surface pressure with a small number of metal component plates.

  In the case of a cylinder head gasket, in order to prevent combustion gas that is corrosive at high temperatures from entering between the metal component plates of the gasket, a grommet that is a U-shaped ring or a folded portion that is a folded metal component plate is provided. It has been arranged and used so as to be convex toward the cylinder bore hole side (see, for example, Patent Document 1).

However, in the case of a grommet or folded portion that protrudes toward the cylinder bore hole side, when the pressure of the combustion gas in the hole to be sealed increases, the pressure of the combustion gas causes the cylinder head to move away from the cylinder block. At this time, the pressure of the combustion gas acts in the direction of making the gasket thinner with respect to the grommet and the folded portion. Therefore, there is a problem that the followability of the gasket seal member with respect to the separation of the engine member is deteriorated and the seal performance is deteriorated.
JP 2006-132714 A

  The present invention has been made in view of the above situation, and an object of the present invention is to improve the sealing performance around the hole to be sealed using the pressure of the fluid to be sealed, and to provide a hole to be sealed. An object of the present invention is to provide a metal gasket excellent in sealing performance and durability capable of generating a high sealing surface pressure by arranging a member for adjusting the surface pressure around it.

  In order to achieve the above object, the metal gasket according to the present invention has two or more metal constituent plates, and faces the sealing target hole of the metal gasket that is sandwiched between two members for sealing. A U-shaped ring whose cross section is convex on the outer peripheral side is disposed between the two metal component plates and a hole to be sealed of at least one metal component plate of the two metal component plates. The folded portion is configured by arranging the end portion of the folded portion inside the U-shaped ring.

  According to this configuration, the arrangement of the U-shaped ring whose cross section is convex on the outer peripheral side increases the pressure of the fluid to be gas-sealed and counters the fastening force of the member that sandwiches the gasket. When the member that sandwiches the gasket is expanded and the pressing force on the gasket decreases, the pressure of the high-pressure fluid is transmitted from the outside of the folded portion into the U-shaped ring, and the force that spreads the U-shaped ring Is increased, and the metal component plates of the gaskets on both sides sandwiching the U-shaped ring are pressed toward the engine member to maintain the seal surface pressure necessary for sealing. Therefore, the followability in the seal is remarkably improved.

  In addition, when the pressure of the fluid to be sealed decreases and the pressing force against the gasket due to the fastening force of the member sandwiching the gasket increases, when the periphery of the hole to be sealed is pressed, the folded portion and the U-shaped ring Since the hermetic chamber is configured, the pressure of the fluid in the hermetic chamber can be used to counter the pressing force. Further, when the pressing force increases, the end of the folded portion serves as a surface pressure adjusting member, which acts as a shim, so that the thickness around the hole to be sealed can be maintained, and the seal generated by this thickness The surface pressure required for sealing can be maintained by the surface pressure. At the same time, the U-shaped ring can be prevented from being crushed by the end of the folded portion inserted therein, so that the durability is also increased.

  Moreover, since the folding | returning part was provided in the circumference | surroundings of the sealing object hole, it can prevent that a metal component board falls apart in this folding | returning part. This eliminates the need for spot welding or caulking to prevent the metal component plates from falling apart.

  In the metal gasket described above, a half bead that opens on the seal target hole side is provided on at least one of the two metal constituent plates sandwiching the U-shaped ring, and the U-shaped ring is disposed inside the half bead. Configure. When this half bead is provided, it becomes easy to dispose a U-shaped ring, and a seal line can be formed with a relatively wide width at the flat part on the seal target hole side of the half bead. The generation can be suppressed, and the sealing function of the half bead is added to improve the sealing performance.

  Said metal gasket WHEREIN: The full bead which protrudes outside is arrange | positioned and comprised in the sealing object hole side part of the said half bead. According to this configuration, a full-bead pressing force can be applied in addition to a half-bead pressing force, so that a seal line with a strong pressing force can be formed.

  According to the metal gasket of the present invention, when the pressure of the fluid to be sealed increases due to the provision of the U-shaped ring having a convex cross section on the outer peripheral side, the folded portion transmits into the U-shaped ring. The U-shaped ring is pressed in the opening direction by the pressure of the fluid, and the metal component plates of the gaskets on both sides sandwiching the U-shaped ring are pressed in the member direction. Therefore, since the pressure of the fluid to be sealed can be used as the sealing surface pressure, the sealing surface pressure increases and the sealing performance can be improved.

  In addition, when the force with which the members on both sides increase the pressure of the gasket increases, the folded portion and the U-shaped ring can form an airtight chamber. I can compete. This effect is particularly great when the fluid is liquid. Further, when the pressing force increases, the end of the folded portion serves as a pressure adjusting member similar to the shim, so that the U-shaped ring can be prevented from being crushed while the periphery of the hole to be sealed The thickness of the film can be maintained, and the seal surface pressure generated by this thickness can maintain an appropriate seal line.

  Next, an embodiment of a metal gasket according to the present invention will be described with reference to the drawings, taking a cylinder head gasket as an example. 1 to 8 are schematic explanatory diagrams, and the dimensions such as the plate thickness, the size of the hole to be sealed, the size of the folded portion, the size of the bead and the like are shown for easy understanding of the configuration. It is exaggerated, different from the actual one.

  A metal gasket according to an embodiment of the present invention is a cylinder head gasket that is sandwiched between an engine member of an engine cylinder head and a cylinder block (cylinder body), and includes a high-temperature and high-pressure combustion gas in a cylinder bore, and The fluid such as cooling water and oil in the cooling water passage and cooling oil passage is sealed.

  The cylinder head gasket includes a plurality of metal component plates (metal substrates) formed of a mild steel plate, a stainless annealed material (annealed material), a stainless tempered material (spring steel plate), or the like. In addition, it is manufactured according to the shape of the engine member such as the cylinder block, and has a cylinder bore hole (combustion chamber hole), a liquid hole for circulating coolant and engine oil, a bolt hole for fastening head bolts, etc. The

  As shown in FIGS. 1 and 2, the cylinder head gasket 1 according to the first embodiment of the present invention is formed into two metal component plates 10 and 20 and a U-shape whose cross section is convex toward the outer peripheral side. The ring 30 is formed. The first metal component plate 10 and the second metal component plate 20 are formed of, for example, a stainless annealed material, and the U-shaped ring 30 is formed of, for example, a stainless spring steel plate.

  At the peripheral edge of the cylinder bore hole 2, the first metal component plate 10 is provided with a half bead 11 that opens on the cylinder bore hole 2 side, and the second metal component plate 20 is provided with a half bead 21 that opens on the cylinder bore hole 2 side. . A U-shaped ring 30 having a rounded portion (folded portion) 31 on the outer peripheral side is disposed between the two half beads 11 and 21.

  Further, the peripheral edge portion of the sealing target hole 2 of the first metal component plate 10 is folded back, and the end portion 12 a of the folded portion 12 is disposed inside the U-shaped ring 30. Further, the peripheral portion of the cylinder bore hole 2 of the second metal component plate 20 is folded back, and the end portion 22 a of the folded portion 22 is disposed inside the U-shaped ring 30. That is, the end portions 12a and 22a of the folded portions 12 and 22 are disposed so as to enter the outer peripheral side of the straight portion of the U-shaped ring in plan view. With this configuration, the end portion 12 a of the folded portion 12 and the end portion 22 a of the folded portion 22 face each other inside the U-shaped ring 30. Between the both end portions 12a and 22a, there may be a gap for connecting the space portion 40 and the cylinder bore hole 2 as shown in FIG.

  However, when there is no gap between the both end portions 12a and 22a, when the pressure P of the combustion gas in the cylinder bore hole 2 becomes high with the gasket 1 being sandwiched between the engine members, As shown in FIG. 1, a gap is generated at least temporarily by the pressure P so that the pressure P of the combustion gas can be transmitted to the inside of the U-shaped ring 3.

  Also on the water hole 3 side, the first metal component plate 10 is provided with a half bead 13 that opens on the water hole 3 side, and the second metal component plate 20 is provided with a half bead 23 that opens on the water hole 3 side.

  With this configuration, when the pressure P of the combustion gas of the engine increases, the pressure in the direction in which the U-shaped ring 30 opens due to the pressure P of the combustion gas transmitted into the U-shaped ring 30 as shown in FIG. P acts to generate a force F1 that presses the metal component plates 10 and 20 on both sides holding the U-shaped ring 30 in the member direction. For this reason, the pressure P of the combustion gas can be used as the surface pressure for sealing, so that the sealing performance is improved. Further, the U-shaped ring 30 makes it difficult for the combustion gas to enter between the metal constituent plates 10 and 20 on the outer peripheral side of the U-shaped ring 30, so that the sealing performance is improved, Durability can be improved.

  Further, when the pressure P of the combustion gas of the engine is reduced and a pressing force F2 is generated in which the engine members on both sides press the gasket 1 from both sides, as shown in FIG. Since the airtight chamber 40a can be configured by the folded portions 12 and 22 and the U-shaped ring 30, the repulsive force of the U-shaped ring 30 and the repulsive force of the folded portions 12 and 22 can be combined. Gas pressure can be applied to counter the pressing force F2. Further, when the pressing force F2 is increased, the end portions 12a and 22a of the folded portions 12 and 22 become pressure adjusting members and play a role of pressure adjustment similar to the shim. The thickness at the portion can be maintained, and an appropriate seal line can be maintained by the seal surface pressure generated by this thickness. At the same time, the U-shaped ring 30 can be prevented from being crushed by the end portions 12a and 22a of the folded portions 12 and 22 inserted therein, so that the durability is also increased.

  Further, since the folded portions 12 and 22 are provided around the sealing target hole 2, it is possible to prevent the metal constituent plates 10 and 20 and the U-shaped ring 30 from being separated by the folded portions 12 and 22. This eliminates the need for spot welding and caulking to prevent the metal constituent plates 10 and 20 and the U-shaped ring 30 from falling apart.

  In addition, the U-shaped ring 30 can be easily disposed by the half beads 11, 21, and a seal line can be formed by a relatively wide flat portion on the seal target hole 2 side. And indentation can be suppressed. In other words, recent engine parts made of aluminum alloy have low rigidity and are easily scratched, so that the seal line part is scratched, and the seal performance deteriorates due to the scratch to obtain an appropriate seal performance. There is a problem that cannot be done, but it is a countermeasure against this problem. Furthermore, since the sealing function of the half beads 11 and 21 is added, the sealing performance is further improved.

  A cylinder head gasket 1A according to the second embodiment of the present invention shown in FIG. 3 includes three metal constituent plates 10, 20, 50 and a U-shaped ring 30 whose section is convex toward the outer peripheral side. . In the second embodiment, the third metal component plate 50 is sandwiched between the first metal component plate 10 and the second metal component plate 20 in the first embodiment. Other than this configuration, the second embodiment is the same as the first embodiment.

  When the third metal component plate 50 is disposed, the thickness of the gasket 1A can be easily adjusted, so that the U-shaped ring 30 and the end portions 12a and 22a of the folded portions 12 and 22 are easily disposed. Further, the half beads 11 and 21 need not be provided with a steep slope, and the adjustment of the seal surface pressure by the half beads 11 and 21 is facilitated.

  The cylinder head gasket 1B according to the third embodiment of the present invention shown in FIG. 4 includes three metal component plates 10, 20, and 50 and a U-shaped ring 30 whose section is convex outward. . In the third embodiment, the second metal component plate 20 is not provided in the peripheral portion of the cylinder bore hole 2 without providing the half beads 21 provided on the second metal component plate 20 as in the second embodiment. It is formed flat. A ring 30 having a U-shaped cross section is disposed between the half bead 11 of the first metal component plate 10 and the flat portion of the second metal component plate 20. Other than this configuration, the second embodiment is the same as the second embodiment. In the third embodiment, since there is one half bead 11 than in the second embodiment, the surface pressure of the seal line can be lowered.

  In the structures of the first to third embodiments, the bore surface pressure can be generated using the pressure P of the combustion gas, so that not only the gas sealing ability but also the followability is improved. Furthermore, since the engine member is in contact with a relatively wide flat portion, the contact pressure is not high. Therefore, the impression of the bore portion of the engine member made of aluminum alloy can be reduced. Therefore, it is particularly suitable for an open deck type gasoline engine made of aluminum alloy.

  The cylinder head gaskets 1C, 1D, and 1E of the fourth to sixth embodiments of the present invention shown in FIGS. 5 to 7 are respectively the cylinder head gaskets 1, 1A, and 1B of the first to third embodiments. The first metal component plate 10 is provided with full beads 14, 24 protruding outward on the cylinder bore hole 2 side of the half bead 11 of the first metal component plate 10 and the cylinder bore hole 2 side of the half bead 21 of the second metal component plate 20. By forming a seal line having a high seal surface pressure with the full beads 14 and 24, the full beads 14 and 24 can be applied to an engine having a high combustion gas pressure such as a diesel engine.

  In the embodiment shown in FIGS. 5 and 6, the full beads 14 and 24 are provided on both the first metal component plate 10 and the second metal component plate 20, but the seal surface pressure is provided only on one of them. It can also be reduced. The configurations of the half beads 11 and 21 and the full beads 14 and 24 are appropriately selected according to the required seal surface pressure. In the above description, the full beads 14 and 24 are described as beads having a circular cross-sectional shape. However, the bead shape is not particularly limited in the present invention, and the cross-sectional shape is an arc shape, a sine shape (cosine), or a trapezoidal shape. , A triangular (mountain) shape, or the like.

  Further, in the metal gasket 1F of the seventh embodiment shown in FIG. 8, the first metal component plate 10 is provided with the folded portion 12, but the second metal component plate 20 is not provided with the folded portion. . Alternatively, although not shown, the folded portion 22 is provided on the second metal component plate 20, but the folded portion is not provided on the first metal component plate 10.

  According to this configuration, since the end portion 12a (or 22a) of the folded portion 12 (or 22) is a single sheet, the thickness of the peripheral edge portion of the cylinder bore hole 2 is increased accordingly. It can be reduced as compared with the manufactured sket 1E. Therefore, when reducing the thickness of the peripheral edge of the cylinder bore hole 2, the metal gaskets 1 to 1D of the first to fifth embodiments are the same as the metal gasket 1F of the seventh embodiment. This can be dealt with by omitting one folded portion of the first metal component plate 10 or the second metal component plate 20.

  Although not particularly illustrated, if a seal ring such as a wire ring is disposed inside the U-shaped ring 30, the U-shaped ring 30 can be U-shaped by the seal ring even when the open side of the U-shaped ring 30 is pressed. The open side of the shaped ring 30 can be prevented from being crushed. Therefore, the open side of the U-shaped ring 30 is crushed, and a gap is generated between the U-shaped ring 30 and the metal component plates 10 and 20 sandwiching the ring 30 on the seal target hole 2 side. Combustion gas can be prevented from entering this gap. Therefore, the sealing performance can be further improved.

It is a fragmentary sectional view showing the state where the space between the end portions of the folded portion is open in the cylinder head gasket according to the first embodiment of the present invention. It is a fragmentary sectional view showing the state where the cylinder bore hole peripheral part is pressed by the cylinder head gasket of the 1st embodiment of the present invention. It is a fragmentary sectional view which shows the cylinder head gasket of the 2nd Embodiment of this invention. It is a fragmentary sectional view which shows the cylinder head gasket of the 3rd Embodiment of this invention. It is a fragmentary sectional view which shows the cylinder head gasket of the 4th Embodiment of this invention. It is a fragmentary sectional view which shows the cylinder head gasket of the 5th Embodiment of this invention. It is a fragmentary sectional view showing a cylinder head gasket of a 6th embodiment of the present invention. It is a fragmentary sectional view showing a cylinder head gasket of a 7th embodiment of the present invention.

Explanation of symbols

1, 1A to 1F Cylinder head gasket 2 Cylinder bore hole 3 Water hole 10 First metal component plate 11, 13, 21, 23 Half bead 12, 22 Folded part 12a, 22a Folded part end 14, 24 Full bead 20 Second metal Component plate 30 U-shaped ring 40 Space 40a Airtight chamber 50 Third metal component plate (sub plate)

Claims (3)

  A U-shaped ring having a cross section that protrudes to the outer peripheral side in a portion facing a hole to be sealed of a metal gasket that has two or more metal constituent plates and is sandwiched between two members for sealing. It is disposed between two metal component plates, and at least one of the metal component plates of the two metal component plates is folded back to be sealed, and the end of the folded portion is made of the U-shaped ring. A metal gasket characterized by being placed inside.   The half-bead which opens a seal object hole side is provided in at least one of the two metal component plates sandwiching the U-shaped ring, and the U-shaped ring is disposed inside the half bead. The metal gasket according to 1.   The metal gasket according to claim 2, wherein a full bead that protrudes outward is disposed at a hole target side portion of the half bead.

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