JP4059879B2 - Metal gasket - Google Patents

Description

  The present invention relates to a metal gasket that is sandwiched between two members such as a cylinder head and a cylinder block of an internal combustion engine and seals against gas or liquid.

  When sealing a joint surface between a cylinder head and a cylinder block (cylinder body) of an automobile engine, a metal gasket is sandwiched between them to seal combustion gas, cooling water, lubricating oil, and the like.

  This gasket is clamped by the joint part of the engine member fastened by the fastening bolt to seal the fluid, and the mainstream is a metal gasket. Due to demands for reducing the weight of the engine and reducing manufacturing costs, this metal gasket has shifted from a laminated type with a large number of metal substrates to a metal gasket with a simple structure formed with one or two metal substrates. Is coming.

  For this reason, since the number of component plates is one or two, and the materials that can be used are limited from the viewpoint of reducing the weight of the engine, the types and number of sealing means are also limited, which is relatively simplified. The sealing means must be used, and the sealing function is exerted mainly by the compression / restoration property of the beads formed on the constituent plates.

  And with recent progress in weight reduction, downsizing and higher output of engines, and progress in low pollution, it is required due to low rigidity of engines and increase in maximum combustion pressure (Pmax). It has become difficult to satisfy the sealing performance.

  For example, in the case of a cylinder head gasket, the increase in the maximum output of a diesel engine is particularly significant, and even if the maximum combustion pressure rises, the thickness of the bolt is adjusted to this situation due to the cost of the engine and the convenience of the production line. Normally, the fastening conditions such as the material and the fastening force are not changed.

  As a result, the gasket side is required to have follow-up performance commensurate with an increase in the amount of head lift during an explosion in the cylinder. At the same time, there is a passing phenomenon in which the gasket is strongly struck, the seal bead sag (creep relaxation) proceeds rapidly, the seal surface pressure decreases, and a gas leak is likely to occur. It is also necessary to deal with

  In the case of exhaust manifold gaskets, the engine is becoming thinner, resulting in lower rigidity, which increases the amount of thermal deformation of the manifold, making it difficult to seal the gasket gas. There is.

  On the other hand, the bead at the center of the conventionally used sealing means is a circular full bead in a plan view around the hole to be sealed, and this bead includes passing due to the vertical movement of the cylinder head. Due to the phenomenon, the lower part of the bead, that is, the crotch part is gradually opened, the bead is crushed and the seal surface pressure rapidly decreases, and the sealing performance is remarkably deteriorated.

  Therefore, the present inventor provides a corrugated bead (swell bead) in a plan view around a part of the liquid holes where a sufficient surface pressure for sealing cannot be obtained, and reliably seals the periphery of the liquid hole. A metal gasket for an internal combustion engine configured as described above has been proposed (for example, see Patent Document 1).

  Further, the present inventor has proposed a metal gasket having a double bead provided with an inner bead and an outer corrugated bead surrounding the inner bead around the fluid hole, and applying a wide surface pressure by the outer corrugated bead. (For example, refer to Patent Document 2).

  This corrugated bead is formed by undulating a seal bead in a horizontal direction in plan view, taking a long overall length of the bead, thereby increasing a pressure receiving area of the bead, and undulating the bead, It is hard to be crushed.

  By using this corrugated bead to seal the cylinder bore of the cylinder head gasket of the engine, the compression resistance and spring characteristics are strengthened, the head lift of the engine with a high maximum combustion pressure is followed, and the sag of the bead by strong passing It is conceivable to prevent the increase in the thickness and secure the sealing performance.

However, if a corrugated bead (swell bead) is simply used as the main seal and placed around the hole to be sealed, such as a cylinder bore, a large surface pressure near the hole to be sealed due to high compression resistance and strong spring characteristics. It takes. Therefore, deformation near the hole to be sealed that has low rigidity is promoted. As a result, the sealing function does not work sufficiently, and it becomes difficult to obtain an appropriate sealing performance.
Japanese Patent No. 3026084 Japanese Patent No. 3057445

  The present invention has been made to solve the above-described problems, and an object of the present invention is to prevent deformation near a hole to be sealed, such as a cylinder bore, in an engine or the like that is downsized and reduced in rigidity. It is providing the metal gasket which can exhibit sealing performance.

  In order to achieve the above object, a metal gasket according to the present invention is a metal gasket in which a swell bead having a meandering portion in plan view is formed around a hole to be sealed, and the inner periphery of the swell bead on the side to be sealed The meandering shape of the waviness on the side and the meandering shape of the waviness on the outer peripheral side are made different, and the compression resistance on the inner peripheral side of the waviness bead is formed to be smaller than the compression resistance on the outer peripheral side.

  As a specific shape that makes the inner peripheral side and outer peripheral side meandering shapes different, the waveform of the inner peripheral side swell is increased, that is, the curvature is increased, while the waveform of the outer peripheral side swell is decreased, that is, the curvature is decreased. There are a reduced shape, a shape that widens the bead width of the convex portion on the inner peripheral side in plan view, and a shape that narrows the bead width of the convex portion on the outer peripheral side in plan view.

  With this configuration, the compression resistance on the side of the seal target hole such as a cylinder bore is kept small so that a large surface pressure is not applied in the vicinity of the seal target hole, and the outer peripheral side is less affected by deformation such as bore deformation near the seal target hole. Since the compression resistance is increased, it is possible to improve the sag resistance and improve the sealing performance by comprehensively increasing the seal surface pressure while avoiding deformation in the vicinity of the hole to be sealed.

  Moreover, in said metal gasket, the shape of the said waviness bead is formed by changing partially during a round of a sealing object hole. As a configuration of the partial shape change of the swell bead, there is a configuration in which the swell interval, the bead width, and the swell pitch are partially changed.

  With this configuration, it is possible to exhibit sag resistance and sealing performance corresponding to the difference in the pressing force due to the position of the fastening bolt and the difference in the amount of thermal deformation due to the temperature difference. This temperature difference occurs, for example, because the temperature on the exhaust port side is higher than the temperature on the intake port side, and the vicinity of the portion through which the cooling water passes is lower than the other portions.

  In the metal gasket, a bead is provided on the outer peripheral side of the swell bead and sealed with a double or more seal line. This bead may be a full bead or a half bead. With this configuration, a wavy bead is arranged on the inner peripheral side, and a bead is provided on the outer peripheral side that has little influence on deformation near the hole to be sealed (bore deformation, etc.) to enhance the sealing performance. Sealing performance can be improved while reducing the influence on deformation near the target hole.

  In the metal gasket, when the outer peripheral bead is formed of a half bead, the compression resistance can be made smaller than that of a full bead. Moreover, when the convex part of the waviness bead and the convex part of the bead adjacent to the waviness bead are formed in opposite directions, a high surface pressure (bead top) can be secured on the upper and lower surfaces of the gasket.

  And in said metal gasket, the bead of the said outer peripheral side is formed and formed by a wavy bead. The outer peripheral swell bead is not necessarily formed like the inner peripheral swell bead, but the inner peripheral swell meandering shape is different from the outer peripheral swell meandering shape. It does not have to be.

  With this configuration, the swell bead on the inner peripheral side can suppress the compression resistance on the seal target hole side to avoid deformation near the seal target hole, and the outer peripheral side that has little influence on the deformation near the seal target hole. Since the size of the outer compression resistance can be finely adjusted by appropriately selecting the shape of the waviness bead, an appropriate sealing performance can be obtained while reducing the influence on the deformation in the vicinity of the hole to be sealed.

  In the above metal gasket, the swell bead and the swell bead provided on the outer peripheral side of the swell bead are doubled with respect to the seal target holes on both ends of the three or more seal target holes arranged in a row. In addition to sealing, the swell beads are provided for sealing target holes other than the sealing target holes on both end sides so as to be sealed in a single layer.

  According to this configuration, a waviness bead that is structurally excellent in springiness is used, and the waviness bead is disposed around the hole to be sealed in order to strengthen the seal at both ends. Due to the low rigidity due to the thin design, thermal deformation increases.In particular, even when the amount of deformation at both ends in the longitudinal direction increases and the sealing performance deteriorates, it can follow the thermal deformation and has a sufficient sealing function. Appropriate sealing performance can be obtained. Therefore, the exhaust manifold gasket used for the exhaust manifold of the high performance engine can be particularly effective.

  The present invention is applicable not only to a single plate metal gasket formed of a single metal substrate, but also to a laminated metal gasket in which a plurality of metal substrates are stacked.

  According to the metal gasket of the present invention, the compression resistance on the inner peripheral side is kept small so that a large surface pressure is not applied to the hole to be sealed such as a cylinder bore, and the compression resistance on the outer peripheral side having little influence on deformation near the hole to be sealed is reduced. By increasing the swell and adjusting the compression resistance relative to the seal target hole side and the opposite side, the surface pressure is comprehensively controlled while suppressing the effect on deformation near the seal target hole. Can improve the sag resistance.

  Accordingly, since the sealing performance can be enhanced while preventing deformation near the hole to be sealed, it is possible to provide a metal gasket that can sufficiently secure the sealing performance for a high-performance engine.

  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 and an exhaust gasket as examples.

  The metal gaskets 10A to 10G of the first to fourth embodiments according to the present invention shown in FIGS. 1 to 11 are cylinder head gaskets sandwiched between a cylinder head of an engine and a cylinder block (cylinder body). Thus, the high-temperature and high-pressure combustion gas in the cylinder bore 11 and the liquid such as cooling water and oil in the cooling water passage 15 and the cooling oil passage are sealed.

  A metal gasket 20 according to the fifth embodiment of the present invention shown in FIG. 12 is an exhaust manifold gasket that seals the exhaust manifold (exhaust manifold) portion of the engine, and seals high-temperature exhaust gas.

  1 to 12 are schematic explanatory diagrams, and the aspect ratio of the metal gaskets 10A to 10G, 20 in a plan view, the number of waveforms of the bead waveform shape in a sectional view and a perspective view including a section, The width, aspect ratio, etc. are displayed differently from the actual ones for easier understanding.

  The cylinder head gaskets 10 </ b> A to 10 </ b> G according to the first to fourth embodiments illustrated in FIGS. 1 to 11 are configured by a single metal substrate 10. The metal substrate 10 is formed of a stainless annealed material (annealed material), a mild steel plate, or the like, and is manufactured according to the shape of an engine member such as a cylinder block. The cylinder bore 11, the coolant hole 15, and the engine oil An oil hole (not shown) for circulating the bolt, a bolt hole 16 for fastening bolts, and the like are formed.

  In the first embodiment shown in FIGS. 1 to 4, a wavy bead (corrugated bead) having a meandering portion around a cylinder bore (combustion chamber hole) 11 that is a hole to be sealed in the cylinder head gasket 10 </ b> A in a plan view. ) 12 is formed.

  In the swell bead 12, the swell bead 12 is formed to have a swell shape, thereby making it possible to increase the total length of the swell bead 12 and increase the pressure receiving area, and to prevent the bead from being crushed. Thereby, compression resistance and spring property can be strengthened.

  Further, in the present invention, as shown in FIG. 3 or FIG. 4, the waviness bead 12 is formed by making the meandering shape of the inner peripheral side on the cylinder bore 11 side different from the meandering shape of the outer peripheral side waviness. The compression resistance on the inner peripheral side of the bead 12 is made smaller than the compression resistance on the outer peripheral side.

  In the configuration of FIG. 3, the undulation waveform on the inner peripheral side of the undulation bead 12 is increased, that is, the curvature is increased, while the undulation waveform on the outer peripheral side is decreased, that is, the curvature is decreased. In the configuration of FIG. 4, the bead width of the portion that protrudes toward the inner peripheral side in plan view of the waviness bead 12 is wide, and the bead width of the portion that protrudes toward the outer peripheral side in plan view is narrow.

  With these configurations, the compression resistance on the cylinder bore 11 side is suppressed to a small level so that a large surface pressure does not act on the cylinder bore 11 side, so that bore deformation can be avoided. In addition, since the compression resistance on the outer peripheral side that has little influence on the bore deformation is increased, the seal surface pressure is comprehensively increased, the sag resistance (creep resistance) is improved, and the sealing performance can be enhanced.

  Therefore, among the seal portions of the cylinder head gasket, it is the place where the degree of difficulty of sealing is the highest because of direct contact with the high-temperature and high-pressure combustion gas, and the head lift of the cylinder head increases as the maximum combustion pressure (Pmax) of the engine increases. By the increase, it becomes a seal means having good sag resistance and followability with respect to the seal of the combustion chamber hole 11 which is most susceptible to the influence. That is, it becomes a sealing means that can follow the increase in head lift in an engine having a high maximum combustion pressure, and can suppress an increase in bead sag due to strong passing, thereby improving the sealing performance.

  In the second embodiment shown in FIGS. 5 to 7, as in the first embodiment, the cylinder head gaskets 10 </ b> B, 10 </ b> C, and 10 </ b> D are flat around the cylinder bore (combustion chamber hole) 11 that is a hole to be sealed. The waviness bead 12 having a meandering portion is formed. The waviness bead 12 is formed by making the meandering shape of the inner peripheral side on the cylinder bore 11 side different from the meandering shape of the waviness on the outer peripheral side, and the magnitude of the compression resistance on the inner peripheral side of the waviness bead 12 on the outer peripheral side. The compression resistance is made smaller.

  In the second embodiment, the shape of the swell bead 12 is further changed partially as shown in FIG. 5 to FIG. 7 during one round of the cylinder bore 11. With this configuration, the size of the pressing force due to the bolt fastening and the amount of thermal deformation due to the engine operation in the circumferential direction of the cylinder bore 11 are finely supported.

  In other words, the shape of the swell bead 12 is partially compressed by changing the swell interval of the swell bead 12, the width of the bead 12, the pitch of the swell, etc. during one round of the cylinder bore 11. Different resistance, resilience and creep resistance, so that sag resistance and sealing performance can be demonstrated to cope with differences in pressing force due to fastening bolt position and thermal deformation due to temperature difference. To.

  In the cylinder head gasket 10B of FIG. 5, the undulation interval of the swell bead 12 is formed narrower on the exhaust side (lower side in the figure) than on the intake side (upper side in the figure). Even if the undulations of the undulation beads 12 are the same, the surface pressure generated by the different undulation intervals is different. Therefore, when the sealing conditions around the cylinder bore 11 are greatly different in the circumferential direction, the undulation interval is changed. Correspond. In general, high seal surface pressure and sag resistance can be obtained in an area where the undulation interval is narrow.

  In the cylinder head gasket 10C of FIG. 6, the width of the bead of the swell bead 12 is formed narrower on the exhaust side (lower side in the figure) than on the intake side (upper side in the figure). Even if the undulations of the undulation beads 12 are the same, the surface pressure generated by the different bead widths is different. Therefore, when the sealing conditions around the cylinder bore 11 are greatly different in the circumferential direction, the bead width is changed. Correspond. Generally, high seal surface pressure and sag resistance can be obtained in an area where the bead is narrow.

  Further, in the cylinder head gasket 10D of FIG. 7, the undulation pitch of the undulation beads 12 is partially changed to be smaller on the exhaust side (lower side in the figure) than on the intake side (upper side in the figure). Since the generated surface pressure varies depending on the pitch of the swell bead 12, the swell pitch is changed when the seal conditions around the cylinder bore 11 differ greatly in the circumferential direction. In general, high seal surface pressure and sag resistance can be obtained in an area with a small pitch.

  Accordingly, the bead swell interval, the bead width, the swell pitch, and the like are appropriately changed even for the cylinder bore 11 in which the seal conditions are severe due to locally different required seal performance. Can respond appropriately.

  In the third embodiment shown in FIGS. 8 to 10, the half bead 13 h and the swell bead 12, or the full bead 12 and the swell bead 13 are combined in order to enhance the seal of the cylinder bore 11 of the cylinder head gaskets 10 </ b> E and 10 </ b> F.

  8 and 9, the undulating bead 12 meandering in a plan view similar to that of the first embodiment is used as the primary seal, and a half bead 13h as a secondary seal is disposed on the outer peripheral side thereof.

  Similar to the swell bead of the first embodiment, this swell bead 12 is different from the meandering shape of the swell on the inner peripheral side which is the cylinder bore 11 side of the swell bead 12 and the meandering shape of the swell on the outer peripheral side. The size of the compression resistance on the inner peripheral side of the swell bead 12 is made smaller than the compression resistance on the outer peripheral side. Further, the outer half bead 13h is formed in a circular shape in plan view.

  8 and 9, the half bead 13h is used in this outer peripheral side bead. However, the compression resistance of the secondary seal on the outer peripheral side should be made larger by using a full bead than when the half bead 13h is used. You can also.

  In FIG. 10, the full bead 12 is disposed on the primary seal, and the undulating bead 13 meandering in the same planar view as that of the first embodiment is disposed on the secondary seal on the outer peripheral side. In FIG. 10, the full bead 12 is used to increase the compression resistance of the primary seal on the inner peripheral side as compared to the case where the half bead is used, but the half bead can also be used according to the required sealing performance.

  Furthermore, in the gasket 10 </ b> F shown in FIG. 10, the convex portions of the primary seal full beads 12 and the convex portions of the swell beads 13 of the secondary seal are arranged in opposite directions. Thus, if the convex part of a bead is formed in the direction opposite to each other, high surface pressure (bead top part) can be secured on the upper and lower surfaces of the gasket.

  According to this configuration, the full bead 12 is provided on the inner peripheral side having little influence on the deformation of the bore to enhance the sealing performance, and further, the swell bead 13 is disposed on the outer peripheral side to reduce the compression resistance on the cylinder bore 11 side. Since the surface pressure is kept small and a large surface pressure is not applied to the cylinder bore 11, the bore deformation can be avoided. Therefore, the sealing performance can be enhanced while reducing the influence on the bore deformation.

  In particular, in light-weight small engines, the overall rigidity is lowered due to the thinning of the engine, and the rigidity around the cylinder bore 11 is affected. When a gasket is attached, the rigidity around the cylinder bore 11 is reduced. However, the non-uniformity of the seal surface pressure becomes large, which is an unfavorable seal condition. However, since the secondary seal waviness beads 13 are provided outside the primary seal beads 12h, 12, the seal band is doubled. Thus, this disadvantageous sealing condition can be compensated.

  In the metal gasket 10G of the fourth embodiment shown in FIG. 11, undulation beads 12 and 13 having different undulation sizes are concentrically arranged in parallel.

  As in the first embodiment, the inner circumferential bead 12 is formed by differentiating the meandering shape of the inner peripheral side of the cylinder bore 11 and the meandering shape of the outer peripheral side of the waviness bead 12. The compression resistance on the inner peripheral side is made smaller than the compression resistance on the outer peripheral side.

  An outer peripheral swell bead 13 is provided outside the inner peripheral swell bead 12 and is formed by making the swell size of the outer peripheral bead 13 smaller than the swell of the inner peripheral bead 12. The seal surface pressure and creep resistance on the outer peripheral side of 11 are further strengthened to enhance the seal.

  In addition, the undulation bead 13 on the outer circumferential side is not necessarily the same as the undulation bead 12 on the inner circumferential side, and the meandering shape of the undulation on the inner circumferential side and the meandering shape of the undulation on the outer circumferential side are different. The configuration may not be formed.

  When the configuration of the metal gasket 10G of the fourth embodiment is adopted, the seal surface pressure and creep resistance on the outer peripheral side of the cylinder bore 11 can be further enhanced as compared with the metal gaskets 10E and 10F of the third embodiment.

  The metal gasket 20 of the fifth embodiment shown in FIG. 12 is a gasket that seals the exhaust manifold. In the gasket used for the exhaust manifold, thermal deformation of the flange tightening the gasket becomes large due to low engine rigidity and high temperature due to exhaust gas. For this reason, there are many cases where sealing becomes difficult.

  On the other hand, in the exhaust manifold gasket 20, as shown in FIG. 12, only the inner circumferential swell bead 22A is used for the seal target hole 21A, and thermal deformation is particularly large. For the sealing target hole 21B, an inner circumferential swell bead 22B and an outer circumferential swell bead 23B are provided and arranged in a double manner.

  As shown in FIG. 12, the inner peripheral swell bead 22A with respect to the center seal target hole 21A is meandering the inner peripheral swell on the seal target hole 21A side, similar to the swell bead 12 of the first embodiment. The shape and the meandering shape of the waviness on the outer peripheral side are made different, and the compression resistance on the inner peripheral side of the waviness bead 22A is made smaller than the compression resistance on the outer peripheral side.

  Also, the inner circumferential bead 22B with respect to the sealing target hole 21B on both ends is different from the meandering shape of the inner peripheral swell on the sealing target hole 22B side and the meandering shape of the outer swell on the outer peripheral side. The compression resistance on the inner peripheral side of the waviness bead 22B is made smaller than the compression resistance on the outer peripheral side.

  The outer circumferential swell bead 23B is provided outside the inner circumferential swell bead 22B. The outer circumferential swell bead 23B is not necessarily the inner circumferential bead 23B like the inner circumferential swell bead 22B. The meandering shape of the waviness on the side and the meandering shape of the waviness on the outer peripheral side may be different from each other.

  With this configuration, the followability to thermal deformation is improved, and the sealing performance and durability are improved by utilizing the excellent sag resistance of the swell beads 22A, 22B, and 23B.

  According to the gaskets 10A to 10G and 20 of the first to fifth embodiments having the above-described configuration, the corrugated portions of the swell beads 12, 13, 22A, 22B, and 23B have a large pressure receiving area between the cylinder bores. A bead that can withstand high tightening pressure and has excellent sealing performance with sag resistance.

  Therefore, the cylinder head gasket and the exhaust manifold gasket can withstand high tightening pressure, have excellent sag resistance, generate a seal surface pressure in a wide range, and can reliably seal a hole to be sealed such as a cylinder bore.

  In the above embodiment, the single plate metal gasket formed of a single metal substrate has been described. However, the present invention can also be applied to a laminated metal gasket in which a plurality of metal substrates are stacked. .

It is a top view which shows the metal gasket of 1st Embodiment which concerns on this invention. It is a fragmentary perspective view including the partial cross section which shows the waviness bead of FIG. It is an enlarged plan view of a waviness bead having different waviness waveforms on the inner and outer circumferences. It is an enlarged plan view of a waviness bead having different bead widths on the inner and outer circumferences. It is a top view which shows the metal gasket from which the space | interval of the wave | undulation of 2nd Embodiment which concerns on this invention differs partially in the circumferential direction. It is a top view which shows the metal gasket from which the width | variety of the bead of 2nd Embodiment which concerns on this invention differs partially in the circumferential direction. It is a top view which shows the metal gasket from which the pitch of the wave | undulation of 2nd Embodiment which concerns on this invention differs partially in the circumferential direction. It is a top view which shows the gasket which has arrange | positioned the half bead on the outer peripheral side of the waviness bead of 3rd Embodiment which concerns on this invention. It is a fragmentary perspective view including the partial cross section which shows the waviness bead and half bead of FIG. It is a fragmentary perspective view including the partial cross section which shows the metal gasket which has arrange | positioned a wavy bead on the outer peripheral side of the full bead of 3rd Embodiment which concerns on this invention so that each convex part may become reverse direction mutually. It is a top view which shows the metal gasket which double-arranged the waviness bead from which the magnitude | size of the wave | undulation of 4th Embodiment concerning this invention differs. An exhaust manifold gasket in which a waviness bead is arranged in a single manner with respect to a central seal target hole of the fifth embodiment according to the present invention, and a double waviness bead is arranged with respect to a seal target hole on both ends. FIG.

Explanation of symbols

10A-10G Cylinder head gasket
12 Swell bead (inner circumference bead)
13 Full beads (outer peripheral bead)
13h Half bead (outer bead)
11 Cylinder bore (Seal target hole)
15 water hole
16 bolt holes
20 Exhaust manifold gasket
21A, 21B Seal target hole
22A, 22B Swell bead (inner circumference side bead)
23B Swell bead (outer bead)

Claims (7)

  In the metal gasket in which the waviness bead having a meandering portion in plan view around the hole to be sealed is formed, the waviness shape of the waviness bead on the inner circumferential side of the waviness target hole side of the waviness bead and the waviness shape of the waviness on the outer circumferential side A metal gasket characterized in that it is formed differently, and the compression resistance on the inner peripheral side of the swell bead is smaller than the compression resistance on the outer peripheral side.   2. The metal gasket according to claim 1, wherein the shape of the swell bead is partially changed during one round of the hole to be sealed.   3. The metal gasket according to claim 1, wherein a bead is provided on an outer peripheral side of the swell bead and sealed with a double or more seal line. 4. The metal gasket according to claim 3, wherein the outer peripheral bead is formed of a half bead. 4. The metal gasket according to claim 3, wherein the convex portion of the swell bead and the convex portion of the bead adjacent to the swell bead are formed in opposite directions to each other.   The metal gasket according to any one of claims 3 to 5, wherein the bead on the outer peripheral side is formed of a wavy bead.   With respect to the sealing target holes on both ends of the three or more sealing target holes arranged in one direction, the swell beads and the undulation beads provided on the outer peripheral side of the swell beads are double-sealed, and the both end sides 2. The metal gasket according to claim 1, wherein the swell bead is provided for sealing target holes other than the sealing target hole to provide a single seal.

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