JP2009144810A - Metal gasket - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal gasket including an increased thickness part which can follow minute expansion and contraction movement between a cylinder block and a cylinder head. <P>SOLUTION: The increased thickness part 5 is formed by attaching a grommet 4 along the peripheral edge of a combustion chamber hole 3 in a substrate 2 with the combustion chamber hole 3. A bead 7 is formed so as to surround its periphery and a metal bead 8 composing the bead 7 is projected upward. At least one spring part 6 is subjected to bending molding of a substrate portion, which opposes to the grommet 4 on the side of the combustion chamber hole 3 closer than the formation position of the metal bead 8 and also in a board thickness direction, in the board thickness direction. A stepped part 12 is provided between a portion opposing the metal bead 8 and the grommet, and the metal bead 8 in the substrate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a metal gasket that is interposed between opposed surfaces of a cylinder block and a cylinder head that constitute an engine and seals at least the outer periphery of a combustion chamber of the engine.

For example, as described in Patent Document 1, there is a metal gasket that uses a metal plate provided with a combustion chamber hole opened corresponding to a combustion chamber of an engine as a substrate and forms a bead so as to surround the combustion chamber hole. .
In such a metal gasket, a thickened portion is provided on the inner peripheral side of the bead. Then, by fastening the bolt with a metal gasket interposed between the cylinder block and the cylinder head, the periphery of the combustion chamber is primarily sealed by the large surface pressure generated in the thickened portion. Further, the thickened portion regulates the amount of compressive deformation of the bead to prevent settling of the bead. The beads prevent the combustion gas from the combustion chamber from moving to the outer peripheral side and prevent the cooling water from moving to the combustion chamber side.

  That is, the combustion gas pressure generated in the combustion chamber of the engine is high. In order to seal the high combustion gas pressure, a bead surrounding the combustion chamber hole is provided, and a high surface pressure is generated in the bead. Further, since the repulsive force due to the spring force of the bead may not be able to resist the high combustion gas pressure, the end portion on the combustion chamber hole side is turned back into a thickened portion, and the thickened portion has a high temperature. Primary sealing of high-pressure combustion gas. The thickened portion also serves as a stopper that limits over-compression of the bead.

  Here, the generated surface pressure around the combustion chamber hole may be greatly different between the bolt hole vicinity and between the bolt holes depending on the rigidity of the engine. That is, when viewed in the circumferential direction of the combustion chamber hole, the load applied to the thickened portion by bolt fastening is relatively high near the bolt and relatively low between the bolts. For this reason, if the height of the thickened portion along the circumferential direction of the combustion chamber hole is designed to be constant, the surface pressure at the thickened portion along the circumferential direction of the combustion chamber hole is not uniform. If the surface pressure is not uniform, there may be various problems such as deformation of the combustion chamber hole or gas leakage.

On the other hand, in Patent Document 1, the height of the thickened portion along the circumferential direction of the combustion chamber hole is set such that the height of the thickened portion is relatively lowered in the vicinity of the bolt and is increased between the bolts. Thus, the surface pressure at the thickened portion along the circumferential direction of the combustion chamber hole is made as uniform as possible.
Here, in patent document 1, the said thickening part is formed by folding up the combustion chamber hole edge part of a board | substrate. The thickened portion is constructed by stacking a shim plate on the outer edge of the combustion chamber hole of the substrate or mounting the end of the combustion hole with a grommet from the plate thickness direction as described in Patent Document 2. In some cases, it is realized.
International Publication No. WO2003 / 085294 Pamphlet JP 2003-28300 A

Engines equipped with the metal gasket tend to have lower engine rigidity due to smaller size and lighter weight, thinner fuel, higher compression, higher mechanism, etc., and the thermal load increases and thermal deformation increases. As a result, a high surface pressure is generated in the vicinity of the tightening bolt, but the tendency that deformation between the bolts is large and the surface pressure is low has become remarkable.
Corresponding to this tendency, in the invention described in Patent Document 1, the height of the thickened portion around the combustion chamber hole is relatively high in the vicinity of the bolt so that the tightening surface pressure is averaged over the entire circumference. Molding is performed with an inflection change in the thickness along the circumferential direction.

However, there are the following problems.
That is, the gasket is loaded, the generated gap is measured, and the thickened portion of the gasket is indented according to the measured value to average the surface pressure. Since such a measurement work is required, it takes time to create.
In addition, the tightening surface pressure when the gasket is loaded and fastened can be averaged by measuring and responding in advance as described above. However, thermal deformation occurs during operation of the engine, and the surface pressure changes partially due to the rigidity of the engine, whereas the increased thickness portion cannot follow the deformation. As a result, when mounted on an engine with a large heat load, such as an engine with a high in-cylinder pressure, such as a diesel engine, pressure leakage may occur if there is no deformation following force in the thickened portion as described above.

  The present invention has been made paying attention to such a point, and when the gasket is mounted on the engine, the height is automatically adjusted according to the load, and the cylinder block and the cylinder head due to the explosion generated during operation are performed. It is an object of the present invention to provide a metal gasket having a thickened portion that can follow a minute expansion / contraction motion.

In order to solve the above problems, the invention described in claim 1 of the present invention is a thickened portion in which a metal plate having a combustion chamber hole is used as a substrate, and the plate thickness is increased along the periphery of the combustion chamber hole. The bead is formed so as to surround the combustion chamber hole and the outer periphery of the thickened portion, and the bead is bent in the thickness direction of the metal plate constituting the substrate and is convex on one surface side. A metal gasket comprising at least a metal bead,
The grommet is formed by providing a grommet that sandwiches the opening end of the combustion chamber hole of the substrate from both sides in the plate thickness direction to form the thickened part, and at the combustion chamber hole side of the metal bead formation position and the grommet One or two or more spring portions formed by bending a substrate portion facing in the plate thickness direction in the plate thickness direction are provided.
In the no-load state, the height of the bead is preferably higher than the height of the thickened portion.

Next, the invention described in claim 2 is directed to the metal bead side with respect to the substrate portion between the portion facing the grommet in the thickness direction and the formation position of the metal bead. The step is characterized in that a stepped portion whose portion is offset to the side opposite to the convex side of the metal bead is formed.
Next, the invention described in claim 3 is directed to the configuration described in claim 1 or claim 2, wherein one or more spring portions formed by bending in the plate thickness direction are provided around the combustion chamber hole. It is characterized by being configured to extend one or two or more continuously or intermittently along the direction.

Next, the invention described in claim 4 is characterized in that, in the configuration described in claim 3, the spring portion extends while meandering along the circumferential direction of the combustion chamber hole. .
Next, in the invention described in claim 5, one or more spring portions formed by bending in the plate thickness direction with respect to the configuration described in claim 1 or 2 are arranged around the combustion chamber hole. They are arranged along the direction and extend in a direction away from the combustion chamber hole.

According to the present invention, when the gasket is attached to the engine and fastened, the spring portion molded in the thickened portion deforms in conformity with the engine rigidity. As a result, the surface of the grommet that comes into contact with the joint surface of the cylinder block and the cylinder head is automatically lifted along the circumferential direction to adjust the height of the thickened portion, and the surface along the circumferential direction of the combustion chamber hole. The pressure is equalized.
Further, the spring portion also follows the deformation against the thermal deformation of the engine due to the operation of the engine, so that the thickened portion can follow a minute expansion / contraction motion between the cylinder block and the cylinder head.

In addition, by forming the spring portion by bending the substrate itself in the plate thickness direction, the followable thickened portion can be easily provided, and the thickened amount of the thickened portion can be easily changed. Don't make it bigger.
Here, it is also conceivable to sandwich a shim plate formed with beads inside the thickened portion. In this case, the plate thickness of the shim plate must be smaller than the substrate plate thickness due to the structural relationship other than the periphery of the combustion chamber hole, and the plate width of the shim plate is also limited. For this reason, there is no measure other than to cope with the shape of the bead formed on the shim plate in order to make the thickened part that can be followed, and in the case of an engine with high in-cylinder pressure such as a non-rigid engine or a diesel engine, the deformation following force However, there is a risk of pressure leakage.

Moreover, in the invention described in claim 2, by forming the stepped portion, it is possible to arrange the metal bead forming position close to the grommet. As a result, the engine can be made more compact. That is, even if the thickened portion is formed of grommets, the metal beads can be disposed close to the combustion chamber holes.
In the case where the step portion is not provided, a distance is provided between the metal bead and the grommet as much as a bending deformation allowance between the metal bead and the grommet as in the structure described in Patent Document 2. There is a need.
In the invention described in claim 3, the spring can be generated along the circumferential direction by extending the spring portion along the circumferential direction.
At this time, in the invention described in claim 4, it is possible to earn a spring force that can be generated in the spring portion by meandering.
In the invention described in claim 5, radial spring force can be gained.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic plan view showing the metal gasket according to the present embodiment with a part cut away. 2 is a cross-sectional view taken along the line AA in FIG.
(Constitution)
First, the configuration will be described.
As shown in FIGS. 1 and 2, the metal gasket 1 according to the present embodiment includes a substrate 2 made of a resilient metal plate that can generate a spring force such as a stainless steel material. The substrate 2 has a plurality of combustion chamber holes 3 arranged along the longitudinal direction. Grommets 4 are attached to the open ends of the respective combustion chamber holes 3 along the entire circumference in the circumferential direction. The grommet 4 is formed in a U-shaped cross section so that the opening end of the combustion chamber hole 3 in the substrate 2 is sandwiched from both sides in the plate thickness direction. Thus, the grommet 4 is attached to the substrate 2. By attaching the grommet 4, the inner peripheral side thickened portion 5 is formed on the entire outer edge of the combustion chamber hole 3.

Here, the grommet 4 is comprised from heat resistant steel, such as stainless steel, for example. This is because it is preferable to have heat resistance because it contacts the combustion gas. Moreover, it is preferable that the grommet 4 is lower in hardness than the substrate 2 so as to bend and conform to the joint surface S of the cylinder block or the cylinder head.
Two spring portions 6 extending along the circumferential direction of the combustion chamber hole 3 are formed on the outer edge portion of the combustion chamber hole 3 in the substrate 2, which is a portion located in the grommet 4. . Each spring portion 6 is formed by bending the substrate 2 in the plate thickness direction into a bead shape. The spring portion 6 of the present embodiment is an example in the case of processing so as to be convex toward one surface side of the substrate 2 (upper surface side in FIG. 2). Each spring portion 6 is arranged concentrically with the combustion chamber hole 3 as shown by a one-dot chain line in FIG.

Further, an inner peripheral side seal line SL1 is set so as to endlessly surround the combustion chamber hole 3 and the thickened portion 5, and an inner peripheral side bead 7 is formed along the inner peripheral side seal line SL1.
The inner bead 7 has a synthetic bead structure in which a metal bead 8 and a rubber bead 11 are synthesized. The metal bead 8 is composed of a full bead formed by projecting a metal plate constituting the substrate 2 so as to be convex toward one surface side (the upper surface side in FIG. 2) of the substrate 2. The rubber bead 11 is composed of an elastic sealing material 10 that is fixed to the convex portion side surface of the metal bead 8 and an elastic sealing material 9 that is filled in the concave portion on the back side of the convex portion. A spring force can be generated together with the metal beads 8. In addition, it is preferable that the elastic sealing materials 9 and 10 have heat resistance and oil resistance.

  Further, the metal bead 8 side portion is located between the portion facing the grommet 4 in the plate thickness direction (outer edge portion of the combustion chamber hole) and the formation position of the metal bead 8 with respect to the substrate 2. A step 12 that is offset to the opposite side (lower side in FIG. 2) of the bead 8 is formed. Here, the portion of the substrate 2 between the stepped portion 12 and the metal bead 8 is referred to as a depressed portion 13.

Here, in the present embodiment, the lower surface 4a of the grommet 4 and the lower surface of the depressed portion 13 are set to be flush or substantially flush. However, the lower surface of the depressed portion 13 may be offset downward from the lower surface 4a of the grommet 4, or the lower surface of the depressed portion 13 may be offset upward from the lower surface 4a of the grommet 4. good.
Although FIG. 1 illustrates the case where the height of the inner circumferential side thickened portion 5 and the height of the inner circumferential side bead 7 are the same height in the no-load state, the height of the inner circumferential side bead 7 is illustrated. Is preferably set high.

  A plurality of cooling water holes 14 are opened in the substrate portion located on the outer peripheral side of the inner peripheral bead 7. Further, an outer peripheral side seal line SL2 is set so as to surround the plurality of cooling water holes 14, and an outer peripheral side bead 15 is formed along the outer peripheral side seal line SL2. As shown in FIG. 2, the structure of the outer peripheral bead 15 according to the present embodiment is fixed to the metal bead 16 and the convex side surface of the metal bead 16 and filled in the concave part on the back side of the convex part, and the metal bead 8. A synthetic bead is formed with a rubber bead 17 made of an elastic sealing material capable of generating a spring force. Although the case where the metal bead 16 of the outer peripheral side bead 15 is composed of a step-like half bead is illustrated, it may be a full bead.

Further, an oil hole 18 and a bolt hole 19 are opened on the outer peripheral side of the inner peripheral bead 7, and the outer peripheral bead 15 is disposed so as to surround the outer periphery of the oil hole and the bolt hole 19. It is.
Further, a part of the outer peripheral side end portion of the substrate 2 is folded back to form the outer peripheral side thickened portion 20. The height of the outer peripheral side thickened portion 20 is set lower than the height of the inner peripheral side thickened portion 5 formed at the outer edge of the combustion chamber hole 3.

(Operational effect of this embodiment)
(1) When the metal gasket 1 having the above-described configuration is tightened with a fastening bolt that is interposed between the opposing joint surfaces S of the cylinder block and the cylinder head and penetrates the bolt hole 19, the innermost side with the largest total plate thickness A high surface pressure is generated for the thickened portion 5. This prevents high-pressure combustion gas pressure from moving to the outer peripheral side.

(2) At this time, the tightening load of the tightening bolt is not evenly applied to the inner peripheral side thickened portion 5 along the circumferential direction of the combustion chamber hole 3. That is, the generated surface pressure around the combustion chamber hole 3 differs greatly between the vicinity of the bolt hole 19 and between the bolt holes 19 depending on the rigidity of the engine. For this reason, in the circumferential direction of the combustion chamber hole 3, the spring portion 6 sandwiched between the grommets 4 is deformed to a state close to full bending at a high surface pressure portion near the bolt, and is proportional to the surface pressure between the bolts. The height is automatically adjusted so that the deformation becomes smaller and naturally inflates. That is, the upper and lower positions of the upper and lower surfaces of the grommet 4 face each other in the circumferential direction so as to absorb the deformation of the joint surface S caused by the engine rigidity that occurs when the metal gasket 1 is attached to the engine and fastened. It deform | transforms so that it may adapt to the joint surface S, and a primary seal | sticker of combustion gas is performed. Further, the position of the upper and lower surfaces of the grommet 4 is deformed up and down following the thermal deformation of the engine that occurs during engine operation, so that engine pulsation due to the high-pressure combustion gas that occurs during the explosion in the combustion chamber can be absorbed.

(3) Further, the inner peripheral side thickened portion 5, together with the outer peripheral side thickened portion 20, improves the durability of each bead 7, 15 by regulating the deformation amount of each bead 7, 15 in the plate thickness direction. To do.
(4) Further, even if the inner peripheral bead 7 is elastically deformed in the plate thickness direction and the combustion gas passes through the position of the inner peripheral thickening portion 5, the combustion gas moves to the outer peripheral side. While preventing, the cooling water which passes the cooling water hole 14 is prevented from moving to the combustion chamber side. That is, by providing the inner peripheral bead 7, the combustion gas can be double-sealed.
At this time, since the inner peripheral bead 7 of the present embodiment is constituted by the metal beads 8 and the rubber beads 11, the combustion gas and the cooling water are more effectively sealed.
Here, the role of the rubber bead 11 made of the elastic sealing materials 9 and 10 in the synthetic bead is that the high-pressure gas from the combustion chamber hole 3 side is first located at the joint surface S portion facing the thickened portion 5. Even if the gas leaks through the minute groove, the groove is filled with the elastic deformation of the elastic sealing materials 9 and 10 at the position of the inner peripheral seal line SL1, so that high-pressure gas leaks. Can be completely blocked from moving to the cooling water hole 14 side and sealed.

Further, even when cooling water enters from the opposite side (outer peripheral side) of the inner peripheral side seal line SL1, the flexible rubber beads 11 can be completely blocked and sealed up to the tool mark. Here, since the elastic sealing material 9 filled in the concave portion does not directly contact the cooling water, it does not change in quality. On the other hand, in the elastic seal material 10 on the convex side, the end surface of the portion closer to the cooling water hole 14 than the metal bead 8 is in contact with the cooling water, and the portion that is in contact with the cooling water is not used because the designated cooling water is not used. Even if the quality of the elastic sealing material 10 in the portion is deteriorated due to deterioration, the elastic sealing material 10 portion on the inner side of the metal bead 8 is separated by the convex portion of the metal bead 8, thereby cooling water. Since there is no direct contact, it is possible to guarantee a complete seal over the long term. Further, as for the width of the rubber bead 11, for example, even if the width of the elastic sealing materials 9 and 10 on the narrow concave portion side is about 2.5 mm, the width on the convex side can be designed to be wider. Can be sealed. Moreover, even if the seal surface scratches that occur during conveyance are formed so as to straddle the bead width, it is possible to seal the surface with the rubber beads 11 so as to completely seal the seal surface flaw.
In addition, since the contact surfaces that contact the bonding surface S are the soft elastic sealing materials 9 and 10, the gasket coefficient can be reduced. As a result, the overall tightening load can be reduced without requiring a large load, that is, the tightening axial force of the bolt can be reduced.

(5) Even if the inner peripheral side thickened portion 5 is formed by the grommet 4, the metal beads 8 can be disposed close to the thickened portion 5 by forming the stepped portion 12.
The reason will be described.
The metal beads 8 have high sealing pressure at the positions of the left and right corners 9a and 9b at the ends in the width direction and the tops of the arcuate convex portions. In the present embodiment, by providing the step portion 12, the lower surface position of the combustion chamber hole side corner portion 9 a in the width direction end portion of the metal bead 8 is equal to or close to the lower surface position of the grommet 4. It has become. For this reason, even if the metal bead 8 is arranged close to the inner peripheral side thickened portion 5 by the grommet 4, a seal pressure having a predetermined magnitude is formed at the combustion chamber hole side corner portion 9 a of the end portion in the width direction of the metal bead 8. Can be generated.
The fact that the inner peripheral bead 7 can be disposed close to the inner peripheral thickening portion 5 makes it possible to provide a metal gasket that can cope with the downsizing of the engine.

(Modification or application)
(1) In the said embodiment, the case where it comprised by the synthetic bead of the metal bead 8 and the rubber bead 11 as the inner peripheral side bead 7 was illustrated. Instead of this, the inner circumferential bead 7 may be formed of only the metal beads 8. That is, the rubber bead 11 may be omitted.
(2) In the above embodiment, the case where two spring portions 6 are provided is illustrated. One or three or more spring portions 6 extending along the combustion chamber hole 3 may be provided. In addition, each spring part 6 does not need to completely surround the outer periphery of the combustion chamber hole 3. As shown in FIG. 3, a plurality of spring portions 6 extending along the combustion chamber hole 3 may be disposed so as to surround the entire circumference of the combustion chamber hole 3.

(3) In the said embodiment, the case where the metal plate which comprises the board | substrate 2 was processed and shape | molded so that the spring part 6 might protrude only to the convex side of the metal bead 8 was illustrated. Instead of this, as shown in FIG. 4, two spring portions 6 may be provided so as to protrude on both the upper and lower sides. When the two spring portions 6 are provided, the portion of the substrate 2 facing the grommet 4 can be made smaller by providing the two spring portions 6 so as to be convex on both the upper and lower sides.

(4) Moreover, in the said embodiment, the case where the metal bead 8 which comprises the said inner periphery bead comprised with a full bead was illustrated. Instead of this, as shown in FIG. 4, the metal bead 8 constituting the inner circumferential bead 7 may be constituted by a step-shaped half bead. Even in this case, the rubber beads 11 may be omitted.
(5) Moreover, in the said embodiment, the case where each spring part 6 extended in circular arc shape along the circumferential direction of the combustion chamber hole 3 was illustrated. Instead of this, as shown in FIGS. 5 and 6, the spring portion 6 may extend along the circumferential direction of the combustion chamber hole 3 while meandering at least a part thereof.
In this case, the spring portion 6 may meander to the inside and outside of the concentric line with the combustion chamber, and the meandering pitch may be made fine by increasing the meandering pitch at a portion where a lot of surface pressure is required, so that the generated surface pressure is made uniform. In such a case, the spring force of the spring portion 6 can be increased correspondingly by meandering.

(6) Moreover, in the said embodiment, the case where the spring part 6 extended along the circumferential direction of the combustion chamber hole 3 was illustrated. Instead, as shown in FIGS. 7 and 8, a plurality of spring portions 6 are provided so as to be aligned along the circumferential direction of the combustion chamber hole 3, and each spring portion 6 is separated from the combustion chamber hole 3 side. It may be extended. In FIG. 8, the case where the some spring part 6 is arrange | positioned radially toward the outer-diameter direction centering on the center of the combustion chamber hole 3 is illustrated.

(7) FIG. 9 shows another modification. This modification is an example in which the spring portion 6 and the step portion 12 are made continuous. By making the spring part 6 and the step part 12 continuous, the metal bead 8 can be arranged closer to the grommet 4. In FIG. 9, the lower surface side portion of the step side grommet 4 is shortened, and the spring portion 6 and the step portion 12 are made continuous so that the metal bead 8 can be disposed closer to the grommet 4.
(8) Another modification of FIG. 10 is shown. This modification is an example in which the spring portion 6 is partially arranged along the periphery of the combustion chamber hole 3. In this example, two or more spring portions 6 are provided in the portion located between the combustion chamber holes 3. As described above, the number of the spring portions 6 may be set to be large only in the portion where the surface pressure due to the tightening load is low.

It is the top view which fractured | ruptured one part which shows the metal gasket which concerns on embodiment based on this invention. It is AA sectional drawing of FIG. It is a top view which shows arrangement | positioning of the spring part of another example which concerns on embodiment based on this invention. It is sectional drawing which shows the metal gasket of another example which concerns on embodiment based on this invention. It is sectional drawing which shows the metal gasket of another example which concerns on embodiment based on this invention. It is a top view which shows arrangement | positioning of the spring part of another example which concerns on embodiment based on this invention. It is sectional drawing which shows the metal gasket of another example which concerns on embodiment based on this invention. It is a top view which shows arrangement | positioning of the spring part of another example which concerns on embodiment based on this invention. It is sectional drawing which shows the metal gasket of another example which concerns on embodiment based on this invention. It is a top view which shows arrangement | positioning of the spring part of another example which concerns on embodiment based on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal gasket 2 Board | substrate 3 Combustion chamber hole 4 Grommet 4a Lower surface 5 Inner peripheral side thickening part 6 Spring part 7 Inner peripheral side bead 8 Metal bead 8a Corner | angular part 11 Rubber bead 12 Step part 13 Drop part 14 Cooling water hole

Claims (5)

A metal plate having a combustion chamber hole is used as a substrate, and a thickened portion is formed along the periphery of the combustion chamber hole, and a bead is formed so as to surround the outer periphery of the combustion chamber hole and the thickened portion. The bead is a metal gasket provided with at least a metal bead that is bent in the thickness direction by bending a metal plate that constitutes the substrate in the thickness direction,
The thickness is increased by providing a grommet that sandwiches the opening end portion of the combustion chamber hole of the substrate from both sides of the plate thickness direction to constitute the above thickened portion,
1 or 2 or more spring parts formed by bending in the thickness direction the board | substrate part which opposes the said grommet in the thickness direction at the combustion chamber hole side rather than the formation position of the said metal beads. gasket.   That the metal bead side portion is offset with respect to the opposite side of the convex side of the metal bead with respect to the substrate portion between the portion facing the grommet in the plate thickness direction and the formation position of the metal bead. The metal gasket according to claim 1, wherein   One or two or more spring portions formed by bending in the plate thickness direction are configured to extend continuously or intermittently one or two or more along the circumferential direction of the combustion chamber hole. The metal gasket according to claim 1 or 2.   The metal gasket according to claim 3, wherein the spring portion extends while meandering along a circumferential direction of the combustion chamber hole.   The one or more spring portions formed by bending in the plate thickness direction are arranged along the circumferential direction of the combustion chamber hole and extend in a direction away from the combustion chamber hole, respectively. The metal gasket according to claim 1 or 2.

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