KR20140133948A

KR20140133948A - Metal gasket

Info

Publication number: KR20140133948A
Application number: KR1020147029070A
Authority: KR
Inventors: 고사쿠 우에타
Original assignee: 니혼 메타루 가스켓토 가부시키가이샤
Priority date: 2012-04-09
Filing date: 2012-04-09
Publication date: 2014-11-20
Also published as: WO2013153569A1; JP5753315B2; JPWO2013153569A1

Abstract

A metal gasket capable of coping with the miniaturization and weight reduction of the engine and the large exhaust amount is provided. A first region R1 from an end of the combustion chamber hole 7 to a middle position in the width direction of the combustion chamber hole side bead 2 from the side of the combustion chamber hole 7 toward the outer side of the gasket, A second region R2 from a position midway in the width direction of the first region R2 to a position in the middle of a position overlapping with the inside of the cooling water region W / J, three regions R3 of the third region R3, . The thickness of the metal gasket 20 is configured such that the first region R1 is the thickest, the second region R2 is the next thickest, and the third region R3 is the thinnest. This plate thickness is constituted by the sub-plate 4.

Description

{METAL GASKET}

The present invention is a metallic gasket interposed between opposing joining surfaces of a cylinder block and a cylinder head constituting an engine, and is used in an engine in which the cylinder block and the cylinder head are bolted together with a metallic gasket interposed therebetween To a metal gasket.

As a conventional metal gasket, there is, for example, a metal gasket described in Patent Document 1 and Patent Document 2. [

The metal gasket described in Patent Document 1 is formed by laminating a single substrate and a sub-plate thinner than the substrate. On the substrate, a combustion chamber hole is opened and the combustion chamber hole is surrounded by a full bead to form a bead on the combustion chamber hole side. Further, the sub-plate is disposed opposite to the entire surface of the substrate, and is folded back so as to sandwich the substrate therebetween at the side of the combustion chamber hole side. The end of the folded back portion is set in the flat surface of the substrate on the inner peripheral side (combustion chamber hole side) of the combustion chamber side bead.

With this arrangement, only the total thickness (the thickness of the metal gasket) around the combustion chamber hole increases in thickness. That is, the plate thickness of the metal gasket is divided into two types, that is, the inner periphery side of the combustion chamber hole side bead and the outer periphery side (including the combustion chamber hole side bead). As a result, when the metal gasket is mounted on the engine and fastened with a bolt, the thickness increase portion disposed in the flat portion on the combustion chamber hole side of the combustion chamber hole side bead has a role of increasing the surface pressure around the combustion chamber hole, The thickness increasing portion serves as a stopper to restrict the vibration amplitude generated by the combustion explosion at the time of engine operation and to prevent the fatigue failure of the combustion chamber hole side bead. In addition, when the refolding portion is disposed on the convex portion side of the combustion chamber hole bead (FIG. 4), it has a role of preventing the bead on the combustion chamber hole side from being totally bent.

The metal gasket described in Patent Document 2 is also constructed by laminating a single substrate and a sub-plate thinner than the substrate. On the substrate, a combustion chamber hole is opened and the combustion chamber hole is surrounded by the filler so as to form a bead on the side of the combustion chamber hole.

Further, the sub-plate is arranged to face the substrate at the concave portion side of the bead of the combustion chamber hole side. The outer peripheral side end portion of the sub-plate is set so as to overlap with the substrate flat portion located outside the combustion chamber hole side bead. This sub-plate is connected to the combustion chamber hole side and folded back so as to sandwich the substrate at the combustion chamber hole side end portion, thereby forming a folded back portion. At this time, the end of the folded back portion is set on the flat surface of the substrate on the inner peripheral side (combustion chamber hole side) of the convex portion side of the combustion chamber side bead.

As a result, the plate thickness of the gasket is divided into three types from the combustion chamber hole toward the outer peripheral side. That is, the plate thickness from the outer periphery of the gasket to the outer peripheral portion position of the bead in the combustion chamber hole is the thinnest only by the substrate, and the front and rear portions in the width direction including the bead in the combustion chamber hole side, And the second thickness is thinner than that of the combustion chamber hole side beads, and the combustion chamber hole side is thickest in thickness by the substrate and the two side plates.

Thus, the plate thickness of the sub-plate is selected based on the stiffness of the engine, the size of the combustion chamber diameter, the combustion pressure, etc. to completely seal the combustion gas pressure and secure the surface pressure of the cooling water and oil holes.

Japanese Patent Application Laid-Open No. 62-155376 Japanese Patent Application Laid-Open No. 11-2325

Engine technology continues to evolve rapidly, and the increase in heat load and the introduction of high-mecha- nism technology are taking place in order to reduce the size and weight of the engine, improve performance, and introduce energy conservation mechanisms. For this reason, for example, engine stiffness tends to decrease, and a gas or liquid having different conditions such as combustion gas for high temperature and high pressure, cooling water for cooling the generated engine heat, oil for lubricating the engine rotation sliding portion, There have been various problems.

In response to such a decrease in engine stiffness and a tendency to procure parts from the world market due to the spread of the Internet, cost competitiveness is also being compulsory. At present, there is an increasing demand from both sides of performance and cost for metal gaskets It is getting tighter.

Patent Literature 1 and Patent Literature 2 adopt a configuration in which the thickness of the flat portion on the side of the combustion chamber hole becomes larger than the thickness of the combustion chamber bore on the side of the combustion chamber hole side bead. As a result, the surface pressure around the combustion chamber hole is increased by deforming the engine by a thickness increase at the flat portion position on the side of the combustion chamber hole, and the fatigue breaking of the bead of the combustion chamber hole side due to the explosion caused by the engine operation is prevented do.

However, as described above, the engine evolves rapidly, the combustion of the combustion chamber tends to become narrower due to the increase in the diameter of the combustion chamber due to the reduction in size and weight, and the space between the combustion chamber holes becomes narrower than the bead in the combustion chamber hole side. The outer edge portion) tends to become narrower and narrower. In addition, there is a tendency that the cooling water area (water jacket) disposed around the combustion chamber hole also becomes closer to the heat source in order to narrow the spaces between the combustion chamber holes and to increase the cooling effect as the amount of heat generation increases. (The width of the joint surface between the combustion chamber and the cooling water region) of the gasket for sealing the gasket should be designed to be narrow.

There is a possibility that the above-mentioned request can not be satisfied with the configuration of a conventional one, such as a conventional one, of the bead position on the combustion chamber hole side and a sub-plate arranged side by side on both sides of the substrate flat portion inside thereof.

That is, as described above, as the diameter of the combustion chamber increases and the position of the cooling water region approaches the combustion chamber, the sealing surface width of the combustion chamber becomes narrower than the cooling water region position. This leads to a narrowing of the seal surface area provided around the combustion chamber hole. The width of the back side of the sub-plate is set at the position of the combustion chamber hole side bead within the narrowed sealing surface width and the flat side position inside the side of the combustion chamber hole side bead.

However, in order to follow the vibration of the engine in order to follow the deformation, the height of the bead width bead is required to be more than a certain level, but the width of the bead can not be ensured unless the bead width is narrowed. Further, in order to secure the surface pressure by narrowing the bead width, it is necessary to increase the bead height, but the more the bead height is secured, the more the cracks are generated in the substrate.

Further, as the rebound width of the sub-plate is narrowed, a high surface pressure is applied to the folded-back portion of the sub-plate when the engine is mounted and operated. When the engine is made of aluminum with the weight reduction of the engine, . In addition, there is a case where the highest part of the surface pressure becomes the nearest high temperature to the combustion chamber hole and the temperature rises up to a temperature lowering the proof strength of aluminum. From this, as the width capable of forming the refolded part becomes narrower, Or the joint surface of the cylinder block.

As described above, if cracks in the beads or sinking of the engine occur, the surface pressure may be lowered or the torque may be lowered, leading to leakage leakage of the combustion gas.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and it is an object of the present invention to provide a metal gasket capable of coping with the reduction in size and weight of the engine and the increase in the amount of exhaust gas.

According to an aspect of the present invention, there is provided a cylinder head comprising: a combustion chamber; a joint surface of a cylinder block formed on the outer circumferential side of the combustion chamber and having a cooling water passage through which the cooling water passes; As a result,

In a metallic gasket having a combustion chamber hole opened at a position corresponding to a combustion chamber and a combustion chamber hole side bead surrounding the combustion chamber hole,

This metal gasket has a first region from the combustion chamber hole side to the gasket outer periphery side, a first region from the end of the combustion chamber hole to a position midway in the width direction of the combustion chamber hole side bead, a position in the width direction of the combustion chamber hole side bead, And a third region on the outer circumferential side than the second region, and the plate thickness of the metal gasket is set such that the first region is thickest and the second region is thicker than the second region, The third region is thickest, and the third region is the thinnest.

According to another aspect of the present invention, there is provided a metal gasket interposed between a joint surface of a cylinder block formed on a combustion chamber and an outer circumferential side thereof and having a cooling water region through which cooling water passes, and a joint surface of the cylinder head,

One or two or more substrates and sub-plates are stacked,

The substrate includes at least a combustion chamber hole opened at a position corresponding to the combustion chamber, an outer edge of the combustion chamber hole continuing to the combustion chamber hole, a combustion chamber hole side bead surrounding the combustion chamber hole and the combustion chamber hole outer edge, And a cooling water hole which is opened at a position facing the cooling water area,

Wherein the auxiliary plate is formed by arranging the outer peripheral side end portion at a position overlapping the cooling water region and extending back to the combustion chamber hole side and being folded back at the combustion chamber hole side and the end portion of the folded back portion of the sub- And are disposed at positions where they overlap with each other.

According to another aspect of the present invention, the combustion chamber hole side bead is formed by bending the metal plate constituting the substrate so as to be convex on one surface side of the substrate with reference to the combustion chamber hole outer edge portion, Corner portions of the beads extending along the combustion chamber holes are formed, respectively,

The end portion of the folded back portion of the sub-plate is positioned between the corners of the two beads arranged in the width direction, and the folded back portion is disposed on the other surface side of the substrate.

The aspect of the present invention is characterized in that the combustion chamber hole side bead is formed by bending the metal plate constituting the substrate so as to be convex on one surface side of the substrate with reference to the combustion chamber hole outer edge portion, A corner portion of the bead extending along the periphery of the hole is formed,

The end portion of the folded back portion of the sub-plate is positioned between the corners of the two beads arranged in the width direction, and the folded back portion is disposed on one surface side of the substrate, May be formed in a shape corresponding to the shape of the surface of the opposing substrate.

The aspect of the present invention is characterized in that the combustion chamber hole side bead is formed by bending the metal plate constituting the substrate so as to be convex on one surface side of the substrate with reference to the combustion chamber hole outer edge portion,

The sub-plate may have an opposite portion facing the concave portion side of the combustion chamber hole side bead at the other surface side of the substrate, and a bead protruding toward the substrate side may be formed at the opposing portion of the sub-plate.

In the aspect of the present invention, the folded back portion of the sub-plate may be folded so as to sandwich the outer edge portion of the combustion chamber hole of the substrate.

According to the aspect of the present invention, it is possible to provide a metal gasket capable of coping with the reduction in size and weight of the engine and the increase in the amount of exhaust gas.

That is, the plate thickness of the gasket is divided into three kinds of plate thicknesses from the combustion chamber hole side toward the outer periphery, and a part of the first thickest region is superposed on a part of the bead of the combustion chamber hole side. Thus, even if the stiffness of the engine is low and the sealing surface width between the combustion chamber and the cooling water region of the engine is narrow, the surface pressure around the combustion chamber hole can be set high while ensuring the bead width of the combustion chamber hole side bead .

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a partially broken plan view showing a metal gasket according to a first embodiment based on the present invention. Fig.
2 is a sectional view taken along the line AA in Fig.
3 is a cross-sectional view showing another example of the first embodiment based on the present invention.
Fig. 4 is a cross-sectional view taken along the line AA in the case where the substrate according to the first embodiment based on the present invention is composed of two substrates.
5 is a cross-sectional view illustrating a metal gasket according to a second embodiment based on the present invention.
6 is a cross-sectional view for explaining another example of the metal gasket according to the second embodiment based on the present invention.
7 is a cross-sectional view for explaining another example of the metal gasket according to the second embodiment based on the present invention.
8 is a cross-sectional view for explaining another example of the metal gasket according to the second embodiment based on the present invention.
9 is a cross-sectional view illustrating a metal gasket according to a third embodiment based on the present invention.
10 is a cross-sectional view for explaining another example of the metal gasket according to the third embodiment based on the present invention.
11 is a view for explaining a case where a folded back portion is provided on the convex portion side of the combustion chamber hole side bead with respect to the embodiment based on the present invention.
12 is a cross-sectional view for explaining an example in which the folded back portion is formed of a plate separate from the sub-plate.

(First Embodiment)

Next, a first embodiment of the present invention will be described with reference to the drawings.

1 is a schematic plan view showing a state in which a metal gasket 20 according to the present embodiment is partially cut away. 2 is a sectional view taken along the line A-A in Fig.

(Configuration)

First, the configuration will be described.

As shown in Figs. 1 and 2, the metal gasket 20 of the present embodiment is constituted by stacking a substrate 1 made of an elastic metal plate capable of generating a spring force, such as stainless steel, and a sub-plate 4. [ The plate thickness of the sub-plate is supposed to be thinner than the plate thickness of the substrate 1, for example. When the spring force is not required to be generated, the auxiliary plate is not required to be a resilient metal plate such as stainless steel, but may be made of soft steel, aluminum or other metal material.

1, a plurality of combustion chamber holes 7 provided corresponding to the combustion chamber 10 of the cylinder block 11 are opened in a predetermined direction. The substrate 1 is provided with a combustion chamber hole 7 and a substrate flat portion (also referred to as a combustion chamber hole outer edge portion 8) located at an outer edge of the combustion chamber hole 7, The bead 2 on the side of the combustion chamber hole is molded. The width of the substrate flat portion is preferably equal to or less than the width of the combustion chamber hole side bead (2). The combustion chamber hole side bead 2 is a full bead formed by bending and shaping the metal plate constituting the substrate 1 so as to be convex on the upper surface side. Corner portions 2a and 2b extending along the outer periphery of the combustion chamber hole 7 are formed at both end portions of the combustion chamber hole side beads 2 of the full beads in the bead width direction and the two corner portions 2a, 2b are convex portions having a circular arc shape protruding upward.

At a portion of the substrate 1 on the outer circumferential side of the combustion chamber hole side bead 2 is provided a plurality of (preferably two or more) cylinders at positions facing the cooling water region W / J of the cylinder block 11 A plurality of cooling water holes 13 are formed along the outer periphery of the combustion chamber hole side bead 2.

1, reference numeral 15 denotes a bolt hole, and reference numeral 14 denotes an oil hole.

On the outer peripheral side of the substrate 1, an outer peripheral bead 3 made of a half bead is formed along the outer periphery so as to surround the cooling water hole 13. [ A bead 17 is formed so as to surround the bolt hole 15 and the oil hole 14.

The sub-plate 4 faces a concave-side surface (lower surface) of the bead 2 on the side of the combustion chamber hole of the substrate 1 and a position overlapping with the cooling water zone W / ) Side end portions of the substrate 1, as shown in Fig. Namely, the sub-plate 4 arranges the outer peripheral side end portion 16 at a position overlapping with the cooling water region W / J. The auxiliary plate 4 extends from the position overlapping with the cooling water region W / J to the side of the combustion chamber hole 7 and is folded back at the end portion on the side of the combustion chamber hole 7, Respectively. The end 6 of the rebound portion 5 of the sub-plate 4 is set at a position overlapping the bead 2 on the combustion chamber hole side. In this embodiment, the end portion 6 of the folded back portion 5 is disposed so as to face the concave portion of the combustion chamber hole side bead 2 located between the two corner portions 2a and 2b. The folded back portion 5 is also disposed on the side (lower surface) side of the concave portion side of the bead 2 on the combustion chamber hole side of the substrate 1.

The metal gasket 20 of the present embodiment has a structure in which the gasket 20 is formed so as to extend from the combustion chamber hole 7 side toward the outer periphery of the gasket and from the outer edge of the combustion chamber hole 7 to the combustion chamber hole side bead 2 (W / J) from the middle position in the width direction of the combustion chamber hole side bead (2) to the middle position in the cooling water zone (W / J) And the third region R3 on the outer circumferential side from the second region R2 and the plate thickness of the metal gasket 20 is set such that the first region R1 is located on the substrate 1 And the second region R2 is the second thickest one per side of the substrate 1 and the sub-plate 4 and the third region R3 is thicker than the substrate 1 only Make the thinnest. That is, the plate thickness of the gasket is set so that the thickness of the gasket gradually decreases from the side of the combustion chamber hole 7 toward the outer periphery of the gasket in three stages.

The plate thickness of the sub-plate 4 is selected by the stiffness of the engine, the seal surface width S, and the like, and the generated surface pressure is adjusted by the plate thickness difference in the three stages in which the sub-plate 4 is thickened.

That is, the metal gasket 20 is interposed between the joint surface of the cylinder block 11 and the joint surface of the cylinder head 12 constituting the engine, and is fastened by bolts.

At this time, the first thickness of the first region R1 is increased, the thickness of the second region R2 is increased next, and the position of the bolt hole 15 located on the outer circumferential side of the substrate 1 is the thinnest The bolt fastening causes the cylinder head 12 of the engine to differentially deform the plate thickness between the bolt holes 15 with the combustion chamber hole 7 interposed therebetween. Since the rigid engine is deformed, a large surface pressure is generated on the gasket in the thickness increasing portion.

(Action effect)

(1) The thickness of the sub-plate 4 is increased by arranging the sub-plate 4 only on the combustion chamber hole 7 side with respect to the cooling water region W / J where the cooling water holes 13 are formed. As a result, even when the stiffness of the engine is low, it is possible to generate a high surface pressure on the combustion chamber hole 7 side than the cooling water zone W / J at the time of bolt tightening.

(2) Further, by folding back the sub-plate 4 in the combustion chamber hole outer edge portion 8, the plate thickness of the gasket is further increased, so that the load around the combustion chamber hole 7 is increased. That is, the increased thickness portion (the combustion chamber hole outer edge portion 8) around the combustion chamber hole 7 becomes a high surface pressure to prevent the gas from leaking from the combustion chamber 10.

Here, by reducing the size, weight and high performance of the engine, the stiffness of the engine is lowered, the tightening load is increased, and the distance between the combustion chamber 10 and the cooling water region W / J is also shortened. That is, the seal surface width S, which is the joint surface portion between the combustion chamber 10 and the cooling water region W / J, becomes narrow. The metal gasket 20 also has the combustion chamber hole outer peripheral portion 8 (substrate flat portion) overlapping with the seal surface width S at the portion of the combustion chamber hole 7 that is closer to the combustion water hole 13 than the cooling water hole 13, And the seal width for forming the combustion chamber hole side bead (2) becomes narrow. At this time, since it is difficult to make the width of the combustion chamber hole side bead 2 too narrow, the width of the combustion chamber hole outer edge portion 8 tends to become narrow.

When the end portion 6 of the rebound portion 5 of the sub-plate 4 is positioned only in the combustion chamber hole outer edge portion 8 as in the conventional case when the combustion chamber hole outer edge portion 8 is narrowed, An excessive load is exerted on the engine joint surface at the combustion chamber hole outer edge portion 8 having a high surface pressure accompanied with a decrease in the rigidity of the engine. As a result, the surface pressure around the combustion chamber hole 7 may be lowered.

In contrast, by extending the end portion 6 of the folded back portion 5 until it is located in the recess of the combustion chamber hole side bead 2, even if the width of the combustion chamber hole outer edge portion 8 becomes narrow, It is possible to suppress the depressed deformation of the joint surface in the portion 8 and to reliably generate a high surface pressure in the combustion chamber hole outer edge portion 8.

In addition, by extending the end portion 6 of the return-back portion 5 until it is located in the concave portion of the combustion chamber hole side bead 2, even if the seal surface width S is narrowed, do. As a result, it is also possible to avoid the difficulty of folding back. This also makes it possible to freely design the bead width even under a narrow seal surface width S.

(3) In the present embodiment, the first region R1 whose first thickness is increased is positioned in the concave portion of the combustion chamber hole side bead 2 from the end of the combustion chamber hole 7. The bead 2 on the side of the combustion chamber hole is almost entirely bent at the corner 2a of the combustion chamber hole 7 side (the corner portion 2a in the first region R1) ) To generate a spring force. On the other hand, in the corner portion 2b (the corner portion 2b in the second region R2) on the cooling water hole 13 side, the plate thickness difference between the first region R1 and the second region R2 (The thickness of the recess 4).

Therefore, the combustion chamber hole side bead 2 has a repulsive potential spring force at the corner portion 2b (the corner portion 2b in the second region R2) on the cooling water hole 13 side. This repulsive potential spring force improves the sealing performance against the expansion shrinkage between the bonding surfaces for the high-temperature and high-pressure gas which is pulsated by the explosion in the combustion chamber 10, thereby further improving the sealability.

Will be described in more detail. A vibration amplitude is generated between the cylinder block 11 and the cylinder head 12 by the explosion in the combustion chamber 10 when the engine is operating. At this time, the repulsive force of the gasket also cooperates to make it smile, but the expansion and contraction is repeated. The repulsive potential spring force follows the widening deformation which is the cause of the deterioration, and the surface pressure drop is suppressed to the minimum.

Further, since the folded back portion 5 having the above-described configuration is not provided on the convex side of the combustion chamber hole side bead 2, there is no or small stopper function for regulating the compressive deformation of the convex portion of the combustion chamber hole side bead 2. Conversely, when folding back to the convex side of the combustion chamber hole side bead 2, since the bead surface pressure of the plate thickness of the sub-plate 4 is attenuated by restraining the compressive deformation of the convex portion, it is necessary to increase the bead height accordingly. In the present embodiment, it is not necessary to increase the bead height by the regulation amount.

(4) Since the outer peripheral end portion 16 of the sub-plate 4 is disposed in the cooling water region W / J, even if a gasket is disposed between the opposing joining surfaces, Thereby preventing a load from being applied. The end portion 6 of the rebound portion 5 of the sub-plate 4 is disposed in the recess of the combustion chamber hole side bead 2 so that the end portion 6 of the rebound portion 5 of the sub- ) In the case where a large load is applied. As a result, the joint surfaces are prevented from being scratched at the corners of the end portions 16 and 6 of the sub-plate 4 as much as possible.

(Modified example)

2, there is one combustion chamber hole side bead 2 surrounding the combustion chamber hole 7. However, as shown in Fig. 3, the combustion chamber hole side bead 2 is double May be used. 3 illustrates a case in which the bead 2 on the outer circumferential side of the combustion chamber hole is formed as a half bead. The end portion 6 of the refolded portion 5 is disposed in the concave portion of the combustion chamber hole side bead 2, which is made of a full bead on the inner circumferential side.

(2) FIG. 4 illustrates a case where two substrates 1 are stacked. In this example, two substrates 1 are arranged opposite to the concave sides of the combustion chamber hole side beads 2, and the sub-plates 4 having the above arrangement are arranged between the two substrates 1 Yes.

Here, the two substrates 1 may be arranged so that the convex portions of the combustion chamber hole side beads 2 face each other. In this case, the sub-plate 4 having the above-described structure may be disposed on the concave portion side of one of the two substrates 1.

(Second Embodiment)

Next, a second embodiment of the present invention will be described with reference to the drawings. The same components as those in the first embodiment are denoted by the same reference numerals.

(Configuration)

The basic configuration of the second embodiment is the same as that of the first embodiment, but is an example in which the sub-plate 4 is disposed on the convex side of the combustion chamber hole side bead 2 as shown in Fig.

That is, the sub-plate 4 faces the convex-side surface (upper surface) of the bead 2 on the combustion chamber hole side of the substrate 1. The auxiliary plate 4 is arranged at a position overlapping with the cooling water area W / J at the outer peripheral side end and extended from the position overlapping the cooling water area W / J to the combustion chamber hole 7 side end, A folded back portion 5 is formed at the end portion on the side of the combustion chamber hole 7 so as to be folded downward so as to sandwich the combustion chamber hole outer edge portion 8 of the substrate 1 therebetween. The end portion 6 of the folded back portion 5 of the sub-plate 4 is disposed so as to be located in the recess of the combustion chamber hole side bead 2.

5, the shape of the sub-plate 4 is formed so as to conform to the shape of the substrate 1, including the folded-back portion 5, so that the sub-plate 4 is arranged as far as possible on the surface of the substrate 1 And is set to be in contact. That is, the portion of the bead 2 opposite to the convex portion on the side of the combustion chamber hole is convex upward in the same manner as the convex portion of the combustion chamber hole side bead 2. Also, the portion of the refolded portion 5 opposed to the recess of the combustion chamber hole side bead 2 is also deformed upward along the recessed surface.

Other configurations are the same as those of the first embodiment.

(Action effect)

(1) The same operational effects as those of the first embodiment can be produced.

(2) With respect to the sub-plate 4, a convex portion and a concave portion of the bead 2 on the side of the combustion chamber hole are formed. As a result, the displacement of the sub-plate 4 relative to the substrate 1 is reduced.

Further, the sub-plate 4 is not necessarily an elastic metal body. When the sub-plate 4 is made of elastic metal, the spring force of the bead 2 on the side of the combustion chamber hole can be increased by the spring of the sub-plate 4 as much.

(Modified example)

(1) A case in which the combustion chamber hole side bead 2 is formed with half beads is shown in Fig. The bead 2 on the side of the combustion chamber hole formed of the step-shaped half bead is bent and formed so as to protrude upward with reference to the combustion chamber hole outer edge portion 8 so that the upper side is convex and the concave portion is formed on the lower side.

As described above, the sub-plate 4 extends along the upper surface of the substrate 1, which is the convex portion side of the combustion chamber hole side bead 2, and at the side of the combustion chamber hole 7 side, And is folded back downward so as to sandwich the outer edge portion 8 therebetween to form a folded back portion 5. The end portion 6 of the folded back portion 5 of the sub-plate 4 is disposed so as to be located in the recess of the combustion chamber hole side bead 2.

The effect is the same as above.

(2) Figs. 7 and 8 illustrate a case where two substrates 1 are provided. In this example, two substrates 1 are arranged with the concave portion of the combustion chamber hole side bead 2 opposed to each other. On one of the two substrates 1, (4). The effect is the same as above.

Further, two boards 1 may be arranged with the projections of the beads 2 on the side of the combustion chamber hole facing each other.

(Third Embodiment)

Next, a third embodiment of the present invention will be described with reference to the drawings. The same components as those in the above-described embodiments are denoted by the same reference numerals.

(Configuration)

The basic configuration of the third embodiment is the same as that of the first embodiment described above. As shown in Fig. 9, the sub-plate 4 is disposed so as to face the concave-side surface of the substrate 1.

However, this embodiment differs from the first embodiment in that a bead made of a full bead protruding toward the concave side is formed in a portion of the sub-plate 4 facing the concave portion of the bead 2 on the side of the combustion chamber hole. Further, the sub-plate 4 is made of an elastic metal plate.

The rest of the configuration is the same as that of the first embodiment.

(Action effect)

(2) When the combustion chamber hole side bead 2 made of the full bead molded on the substrate 1 is compression-deformed, the portion (corner portions 2a and 2b) at which the convex surface side starts to protrude (corner portions 2a and 2b) The contact area is narrow and a high surface pressure is generated. On the other hand, since the convex surface side of the combustion chamber hole side bead 2 having a circular arc shape corresponds to the upper side joint surface, the contact area is wide, and the surface pressure per unit of the corner portions 2a and 2b It is weaker.

And the beads of the sub-plate 4 are arranged on the lower side of the convex surface side. The beads of the beads of the sub-plate 4 are arranged so that the surface pressure of the convex surface side Thereby enhancing the sealability with respect to the joint surface on the upper side.

That is, when the gasket is attached to the engine and fastened with the tightening bolt, the beads of the combustion chamber hole side beads 2 located in the first region R1 and the beads of the sub-plate 4 are deformed close to full bending , And the combustion chamber hole side bead (2) also maintains the rebound energy of the bead formed in the side plate (4). This repulsive energy is followed by a momentary open gap that occurs due to repeated expansion and contraction in engine operation. Further, the convex side of the bead of the substrate 1 having a large ground surface area on the sealing surface is supplemented with the bead of the side plate 4, although the bonding surface pressure is lower than the ground side of the concave side.

(Modified example)

(1) Fig. 10 illustrates a case where there are two substrates 1. In this example, two substrates 1 are arranged opposite to the concave sides of the combustion chamber hole side beads 2, and the sub-plates 4 having the above arrangement are arranged between the two substrates 1 Yes.

(2) In this embodiment, the end portion 6 of the folded back portion 5 of the sub-plate 4 is set to be located in the concave portion of the combustion chamber hole side bead 2 in the entire embodiment.

However, the end portion 6 of the rebound portion 5 of the sub-plate 4 may be disposed so as to face the convex portion side of the combustion chamber hole side bead 2.

This example is shown in Fig. In this example, the sub-plate 4 is disposed on the side of the concave portion of the combustion chamber hole side bead 2, and the upper side is folded back so as to sandwich the substrate 1 at the side of the combustion chamber hole 7 side, 5 is disposed at a midway position of the convex surface of the convex portion of the combustion chamber hole side bead 2.

In this example, the side of the convex portion of the combustion chamber hole side bead 2, that is, the portion of the sub-plate 4 located on one surface side of the substrate 1 has a shape conforming to the shape of the surface of the opposing substrate have. This makes it possible to reduce misalignment between the substrate 1 and the sub-plate 4 even if misalignment occurs due to a difference in thermal expansion between the engine and the gasket material.

In this example, the concave portion side of the combustion chamber hole side bead 2, that is, the portion of the sub-plate 4 located on the other surface side of the substrate 1 is also shaped to conform to the shape of the surface of the opposing substrate have. This makes it possible to further reduce misalignment between the substrate 1 and the sub-plate 4, even if misalignment occurs due to a difference in thermal expansion between the engine and the gasket material.

In this case, it is preferable that the edge of the end portion 6 of the folded back portion 5 be rounded or the thickness gradually decreases toward the tip end.

It is preferable that the position of the end portion 6 of the refolded portion 5 be set at a position where the convex portion top 2d of the combustion chamber hole side bead 2 is displaced. Particularly, the combustion chamber hole 7 side is preferable to the convex portion top 2d of the combustion chamber hole side bead 2. Particularly, the height of the end portion 6 of the backward folded portion 5 is preferably as high as not more than the convex portion top 2d of the combustion chamber hole side bead 2.

(3) In the entire embodiment, the thickness of the gasket is set to change in three steps from the combustion chamber hole 7 toward the outer periphery by providing the folded back portion 5 in the sub-plate 4, . The configuration may be achieved by laminating and fixing a shim plate to the portion corresponding to the first region R1 instead of forming the folded back portion 5 of the sub-plate 4 . Fig. 12 shows an example in which the folded portion 5 is formed as another plate and is fixed by welding or other methods.

Alternatively, the above configuration may be achieved by adjusting the thicknesses of the substrate 1 and the sub-plate 4 itself.

1: substrate
2: Bead of combustion chamber hole side
2a and 2b:
2c:
4:
5:
6: end of the folded back portion
7: combustion chamber hole
8: Outer portion of the combustion chamber hole
9: Beads of the sub board
10: Combustion chamber
11: Cylinder block
12: Cylinder head
13: Cooling water hole
15: Bolt hole
16: outer peripheral edge of the sub board
20: Metal gasket
R1: first region
R2: second region
R3: third region
S: Width of sealing surface
W / J: Cooling water area

Claims

A metal gasket interposed between a joint surface of a cylinder block having a combustion chamber and a cooling water region through which cooling water passes and a joint surface of the cylinder head,
1. A metal gasket comprising a combustion chamber hole opened at a position corresponding to a combustion chamber and a combustion chamber hole side bead surrounding the combustion chamber hole,
The metal gasket has a first region from the combustion chamber hole side toward the gasket outer periphery side, a first region from the end of the combustion chamber hole to a position midway in the width direction of the combustion chamber hole side bead, a position in the width direction of the combustion chamber hole side bead A second region extending to a middle position of a position overlapped with the inside of the cooling water region and a third region located on an outer peripheral side of the second region, the plate thickness of the metal gasket being thickest in the first region, Wherein the second region is thicker next, and the third region is thinnest.

A metal gasket interposed between a joint surface of a cylinder block having a combustion chamber and a cooling water region through which cooling water passes and a joint surface of the cylinder head,
One or two or more substrates, and a sub-plate,
The substrate is provided with at least a combustion chamber hole opened at a position corresponding to the combustion chamber, an outer edge of the combustion chamber hole continuing to the combustion chamber hole, a bead at the combustion chamber hole surrounding the combustion chamber hole and an outer edge portion of the combustion chamber hole, And a cooling water hole which is opened at a position facing the cooling water area,
Wherein the auxiliary plate is formed by arranging the outer peripheral side end portion at a position overlapping with the cooling water region and extending back to the combustion chamber hole side and being folded back at the side of the combustion chamber hole and the end portion of the backward folded portion of the sub- Wherein the metal gasket is disposed at an overlapping position.

3. The method of claim 2,
The bead on the combustion chamber hole side is formed by bending the metal plate constituting the substrate so as to be convex to the one surface side of the substrate with reference to the combustion chamber hole outer edge portion so as to extend along the outer periphery of the combustion chamber hole at both ends of the bead width The corner portions of the beads are formed,
Wherein the end portion of the folded back portion of the sub-plate is positioned between the corners of the two beads arranged in the width direction, and the folded back portion is disposed on the other surface side of the substrate.

3. The method of claim 2,
The bead on the combustion chamber hole side is formed by bending the metal plate constituting the substrate so as to be convex to the one surface side of the substrate with reference to the combustion chamber hole outer edge portion so as to extend along the outer periphery of the combustion chamber hole at both ends of the bead width The corner portions of the beads are formed,
The end portion of the folded back portion of the sub-plate is positioned between the corners of the two beads arranged in the width direction, the folded back portion is disposed on one surface side of the substrate, Is formed in a shape corresponding to the shape of the surface of the opposing substrate.

5. The method according to any one of claims 2 to 4,
The bead on the combustion chamber hole side is formed by bending the metal plate constituting the substrate so as to be convex on one surface side of the substrate with reference to the combustion chamber hole outer edge portion,
Wherein the side plate has an opposing portion facing the concave portion side of the combustion chamber hole side bead at the other surface side of the substrate and a bead protruding toward the substrate side is formed at an opposed portion of the sub plate Metal gasket.

6. The method according to any one of claims 3 to 5,
Wherein the folded back portion of the sub-plate is folded so as to sandwich an outer edge portion of the combustion chamber hole of the substrate.