JP5753315B2 - Metal gasket - Google Patents

Description

  The present invention relates to a metal gasket that is used by being interposed between facing surfaces of a cylinder block and a cylinder head that constitute an engine, and the cylinder block and the cylinder head are interposed with a metal gasket. The present invention relates to the metal gasket used in a bolted engine.

As a conventional metal gasket, there are metal gaskets described in Patent Document 1 and Patent Document 2, for example.
The metal gasket described in Patent Document 1 is configured by laminating a single substrate and a sub-plate that is thinner than the substrate. A combustion chamber hole side bead made of a full bead is molded on the substrate so that the combustion chamber hole is open and surrounds the combustion chamber hole. Further, the sub-plate is disposed so as to face the entire surface of the substrate, and is folded back so as to sandwich the substrate at the end portion on the combustion chamber hole side to form a folded portion. The end portion of the folded portion is set to the substrate flat portion on the inner peripheral side (combustion chamber hole side) than the combustion chamber bead.

  With the above configuration, only the total plate thickness around the combustion chamber hole (the plate thickness of the metal gasket) is increased. That is, the plate thickness of the metal gasket is divided into two types, that is, an inner peripheral side of the combustion chamber hole side bead and a region on the outer peripheral side (including the combustion chamber hole side bead). As a result, when the metal gasket is attached to the engine and fastened with bolts, the thickened portion arranged on the flat portion on the combustion chamber hole side from the combustion chamber hole side bead serves to increase the surface pressure around the combustion chamber hole. The thickened portion serves as a stopper and serves to prevent the fatigue failure of the combustion chamber hole side bead by limiting the amplitude of vibration generated by combustion explosion during engine operation. Further, when the folded portion is disposed on the convex side of the combustion chamber hole side bead (FIG. 4), it serves to prevent the combustion chamber hole side bead from being fully bent.

The metal gasket described in Patent Document 2 is also configured by laminating a single substrate and a sub-plate that is thinner than the substrate. A combustion chamber hole side bead made of a full bead is molded on the substrate so that the combustion chamber hole is open and surrounds the combustion chamber hole.
The sub-plate is disposed opposite to the substrate on the concave side of the combustion chamber hole side bead. An outer peripheral side end portion of the sub-plate is set so as to overlap a substrate flat portion located outside the combustion chamber hole side bead. The sub-plate extends to the combustion chamber hole side and is folded back so as to sandwich the substrate at the end portion on the combustion chamber hole side to form a folded portion. The end of the folded portion is set to the substrate flat portion on the inner peripheral side (combustion chamber hole side) rather than the convex portion side of the combustion chamber bead.

Thereby, the plate | board thickness of a gasket is divided into three types toward an outer peripheral side from a combustion chamber hole. That is, the plate thickness from the gasket outer periphery to the outer peripheral position of the combustion chamber hole side bead is the thinnest only with the substrate, and the front and rear portions in the width direction including the combustion chamber hole side bead and sandwiching the combustion chamber hole side bead are The thickness of the substrate and one auxiliary plate is the second smallest, and the combustion chamber hole side is thicker than the combustion chamber hole side bead by the substrate and two auxiliary plates.
As a result, depending on conditions such as engine rigidity, combustion chamber diameter, combustion pressure, etc., the thickness of the sub-plate is selected to completely seal the combustion gas pressure and to ensure the surface pressure of cooling water, oil holes, etc. Technology.

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

  Engine technology continues to evolve rapidly, and in order to reduce the size and weight of engines, improve performance, and incorporate energy-saving mechanisms, the heat load is increased and high-mechanical technologies are introduced. For this reason, for example, the rigidity of the engine tends to decrease, and a single gas or liquid having different conditions such as cooling water for cooling high-temperature and high-pressure combustion gas and generated engine heat, oil for lubricating the engine rotation sliding portion, etc. Various problems have occurred in the technology of sealing with a metal gasket.

In the present situation where cost competitiveness is forced due to the tendency to procure parts from the global market due to the response to such a decrease in engine rigidity and the spread of the Internet, there is a demand for both performance and cost for metal gaskets. Is becoming increasingly severe.
And in patent document 1 and patent document 2, the structure thickened so that the thickness of the flat part by the side of a combustion chamber hole may become thickest rather than the bead of a combustion chamber hole side is employ | adopted. As a result, the surface pressure around the combustion chamber hole is increased by deforming the engine at the flat part position on the combustion chamber hole side to increase the surface pressure around the combustion chamber hole. Prevent destruction.

  However, as described above, the engine has evolved rapidly, and as the combustion chamber diameter increases as the size of the combustion chamber is increased by reducing the size and weight, the space between the combustion chamber holes becomes narrower. The width of the flat part on the hole side (outer edge part of the combustion chamber hole) tends to become narrower. Further, at the same time as the space between the combustion chamber holes is narrowed, the cooling water region (water jacket) arranged around the combustion chamber holes tends to be arranged closer to the heat source in order to increase the cooling effect according to the increase in the amount of heat generated. This necessitates that the seal surface width of the gasket that seals around the combustion chamber (the width of the joint surface between the combustion chamber and the cooling water region) be designed to be narrow.

The conventional configuration of the auxiliary plate provided on one side of the combustion chamber hole-side bead position and both sides of the substrate flat portion inside the combustion chamber may not meet the above requirement.
That is, as described above, as the combustion chamber diameter increases and the cooling water region position approaches the combustion chamber, the width of the seal surface on the combustion chamber side becomes narrower than the cooling water region position. This leads to a reduction in the width of the seal surface provided around the combustion chamber hole. Within this narrow seal surface width, the combustion chamber hole side bead and the folding width of the auxiliary plate are provided at the flat portion inside the combustion chamber hole side bead.

  However, it is necessary for the bead width and bead height to exceed a certain level in order to follow the vibration of the engine, but the folding width cannot be secured unless the bead width is reduced. Further, in order to secure the surface pressure by narrowing the bead width, it is necessary to increase the bead height. However, the more the bead height is secured, the more the substrate becomes cracked.

  In addition, the smaller the folding width of the secondary plate, the higher the surface pressure applied to the folded portion of the secondary plate when operating with the engine installed. It will exceed the yield strength. In addition, the portion with the highest surface pressure is the place where the combustion chamber hole becomes the highest temperature, and the temperature may rise to a temperature at which the proof stress of aluminum is reduced. As the width becomes narrower, the joint surfaces of the cylinder head and the cylinder block are depressed.

If the crack of the bead or the depression of the engine occurs as described above, the surface pressure may be reduced and the torque may be reduced, and the combustion gas may be blown out.
The present invention has been made paying attention to the above points, and an object of the present invention is to provide a metal gasket that can cope with a reduction in size and weight of an engine and an increase in displacement.

In order to solve the above-described problem, an aspect of the present invention is to provide a connection between a joint surface of a cylinder block including a combustion chamber and a cooling water region formed on an outer peripheral side thereof and through which cooling water passes, and a joint surface of a cylinder head. A metal gasket interposed between
In a metal gasket in which a combustion chamber hole that opens to a position corresponding to the combustion chamber and a combustion chamber hole side bead surrounding the combustion chamber hole are formed,
The metal gasket has a first region from the combustion chamber hole end to the middle position in the width direction of the combustion chamber hole side bead from the combustion chamber hole side toward the gasket outer peripheral side, and a middle position in the width direction of the combustion chamber hole side bead. To the middle part of the position overlapping with the cooling water area, and the third area of the outer peripheral side of the second area, and the thickness of the metal gasket is divided into three areas. It is characterized by being configured such that it is the thickest, the second region is the next thickest, and the third region is the thinnest.

In one aspect of the present invention, the metal gasket is formed by laminating one or two or more substrates and a sub-plate, and the substrate has a combustion chamber hole opened at a position corresponding to combustion presentation, A combustion chamber hole outer edge continuous to the combustion chamber hole, and a combustion chamber hole side bead surrounding the combustion chamber hole and the combustion chamber hole outer edge,
The sub-plate is configured such that an outer peripheral side end portion is arranged at a position overlapping with the inside of the cooling water region, extends to the combustion chamber hole side, and is folded back so as to sandwich the combustion chamber hole outer edge portion on the combustion chamber hole side. Then, by arranging the end of the folded portion of the sub plate at a position overlapping the combustion chamber hole side bead, the thickness of the metal gasket is the largest in the first region and the second region is the next. The portion of the sub-plate facing the combustion chamber hole-side bead is shaped along the shape of the surface of the opposing one substrate, and the third region is the thinnest. The substrate is in contact with the combustion chamber hole side bead of the substrate.

According to the aspect of the present invention, it is possible to provide a metal gasket that can cope with a reduction in size and weight of an engine and an increase in displacement.
In other words, the plate thickness of the gasket is divided into three types of plate thicknesses from the combustion chamber hole side to the outer periphery, and a part of the thickest first region is overlapped with a part of the combustion chamber hole side bead. As a result, even if the rigidity of the engine is low and the seal surface width between the combustion chamber of the engine and the cooling water region is narrow, the surface pressure around the combustion chamber hole is secured while ensuring the bead width of the combustion chamber hole side bead. Can be set high.

It is the partially broken top view which shows the metal gasket which concerns on 1st Embodiment based on this invention. It is AA sectional drawing of FIG. It is sectional drawing which shows the other example which concerns on 1st Embodiment based on this invention. It is AA sectional drawing when the board | substrate which concerns on 1st Embodiment based on this invention is comprised with two sheets. It is sectional drawing explaining the metal gasket which concerns on 2nd Embodiment based on this invention. It is sectional drawing explaining another example of the metal gasket which concerns on 2nd Embodiment based on this invention. It is sectional drawing explaining another example of the metal gasket which concerns on 2nd Embodiment based on this invention. It is sectional drawing explaining another example of the metal gasket which concerns on 2nd Embodiment based on this invention. It is sectional drawing explaining the metal gasket which concerns on 3rd Embodiment based on this invention. It is sectional drawing explaining another example of the metal gasket which concerns on 3rd Embodiment based on this invention. It is a figure explaining the case where a folding | turning part is provided in the convex part side of the combustion chamber hole side bead which concerns on embodiment based on this invention. It is sectional drawing explaining the example in the case of comprising a folding | turning part with a board different from a subplate.

(First embodiment)
Next, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic plan view showing a state in which the metal gasket 20 according to the present embodiment is partially cut away. FIG. 2 is a cross-sectional view taken along the line AA of FIG.

(Constitution)
First, the configuration will be described.
As shown in FIGS. 1 and 2, the metal gasket 20 of the present embodiment is configured by laminating a substrate 1 made of an elastic metal plate capable of generating a spring force, such as a stainless steel material, and a sub plate 4. It is assumed that the thickness of the sub plate is thinner than the thickness of the substrate 1, for example. Further, when the sub plate does not need to generate a spring force, the sub plate does not need to be an elastic metal plate such as a stainless steel material, and may be formed of mild steel, aluminum, or other metal material.

  As shown in FIG. 1, a plurality of combustion chamber holes 7 provided corresponding to the combustion chamber 10 of the cylinder block 11 are opened in the substrate 1 in a predetermined direction. In addition, the substrate 1 has a combustion chamber hole side so that both the combustion chamber hole 7 and the substrate flat portion (also referred to as the combustion chamber hole outer edge portion 8) located at the outer edge of the combustion chamber hole 7 are surrounded endlessly. Bead 2 is molded. The width of the flat substrate portion is preferably equal to or smaller 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 a metal plate constituting the substrate 1 so as to protrude upward. The combustion chamber hole side bead 2 made of a full bead has corner portions 2a and 2b extending along the outer periphery of the combustion chamber hole 7 at both ends in the bead width direction, and a portion between the two corner portions 2a and 2b. 2c becomes the convex part of the cross-sectional arc shape which protruded upwards.

A plurality of cooling water holes are formed in a portion of the substrate 1 on the outer peripheral side of the combustion chamber hole side bead 2 at a position facing the cooling water region W / J (space through which cooling water passes) of the cylinder block 11 in the plate thickness direction. 13 is formed along the outer periphery of the combustion chamber hole side bead 2.
In FIG. 1, reference numeral 15 is a bolt hole, and reference numeral 14 is an oil hole.
Further, 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 is opposed to the surface (lower surface) on the recess side of the combustion chamber hole side bead 2 of the substrate 1 and between the position overlapping the cooling water region W / J and the end portion on the combustion chamber hole 7 side. Only the size of the substrate 1 is opposite to the substrate 1. That is, the sub-plate 4 is disposed at a position where the outer peripheral end 16 overlaps the cooling water region W / J. Further, the sub-plate 4 extends from the position overlapping the cooling water region W / J to the end portion on the combustion chamber hole 7 side, and is further turned back at the end portion on the combustion chamber hole 7 side to form the turned-up portion 5. . And the edge part 6 of the folding | returning part 5 of the subplate 4 is set to the position which overlaps with the said combustion chamber hole side bead 2. In the present embodiment, the end portion 6 of the folded portion 5 is disposed so as to be opposed to the concave portion of the combustion chamber hole side bead 2 between the two corner portions 2a and 2b. The folded portion 5 is also disposed on the surface (lower surface) side of the concave portion of the combustion chamber hole side bead 2 of the substrate 1.

  With the above configuration, the metal gasket 20 according to the present embodiment has a width direction of the combustion chamber hole side bead 2 from the outer edge of the combustion chamber hole 7 toward the outer periphery of the gasket from the combustion chamber hole 7 side when viewed from the plate thickness of the gasket. More than the first region R1 up to the middle position, the second region R2 from the middle position in the width direction of the combustion chamber hole side bead 2 to the middle position of the position overlapping with the inside of the cooling water region W / J, and the second region R2. The metal gasket 20 is divided into three regions, ie, the third region R3 on the outer peripheral side, and the thickness of the metal gasket 20 is the thickest, the first region R1 is two sheets of the substrate 1 and the sub plate 4, and the second region R2 is the substrate. 1 and one of the sub-plates 4 and the second thickest, and the third region R3 is the thinnest only by the substrate 1. That is, the plate thickness of the gasket is set so that the plate thickness gradually decreases in three steps from the combustion chamber hole 7 side to the gasket outer peripheral side.

The thickness of the sub-plate 4 is selected according to the rigidity of the engine, the seal surface width S, and the like, and the generated surface pressure is adjusted by the three-stage plate thickness difference increased by the sub-plate 4.
That is, the metal gasket 20 is inserted between the joint surface of the cylinder block 11 and the joint surface of the cylinder head 12 constituting the engine, and is mounted by fastening the bolt.

  At this time, the first region R1 is thickened most, the second region R2 is thickened next, and the position of the bolt hole 15 located on the outer peripheral side of the substrate 1 is the thinnest. The engine cylinder head 12 is deformed by a plate thickness difference between the bolt holes 15 sandwiching the combustion chamber hole 7. Since the rigid engine is deformed, a large surface pressure is generated on the gasket in the thickened portion.

(Function and effect)
(1) The sub-plate 4 is disposed only on the combustion chamber hole 7 side of the cooling water region W / J where the cooling water hole 13 is formed, and the thickness is increased. As a result, even if the rigidity of the engine is low, it is possible to generate a higher surface pressure on the combustion chamber hole 7 side than the cooling water region W / J when the bolt is fastened.

(2) Further, the load around the combustion chamber hole 7 is increased by folding back the sub-plate 4 at the outer edge 8 of the combustion chamber hole and further increasing the thickness of the gasket. That is, the thickened portion around the combustion chamber hole 7 (combustion chamber hole outer edge 8) has a high surface pressure to prevent gas leakage from the combustion chamber 10.
Here, as the engine is reduced in size, weight, performance, etc., the engine is less rigid, the tightening load is increased, and the distance between the combustion chamber 10 and the cooling water region W / J is also reduced. That is, the seal surface width S that is a joint surface portion between the combustion chamber 10 and the cooling water region W / J is narrowed. Accordingly, also in the metal gasket 20, the combustion chamber hole outer edge portion 8 (substrate flat portion) and the combustion chamber hole side bead 2 overlap the seal surface width S in the portion of the combustion chamber hole 7 than the cooling water hole 13. The seal width for forming is reduced. At this time, since it is difficult to make the width of the combustion chamber hole bead 2 too narrow, the width of the outer edge 8 of the combustion chamber hole tends to be narrow.

When the outer edge 8 of the combustion chamber hole is narrowed, if the end portion 6 of the turned-up portion 5 of the sub-plate 4 is positioned only at the outer edge 8 of the combustion chamber hole as in the prior art, the turned-up width is narrow, so that the engine As the rigidity decreases, an excessive load is applied to the engine joint surface at the outer edge 8 of the combustion chamber hole having a high surface pressure, resulting in a depression. As a result, the surface pressure around the combustion chamber hole 7 may decrease.
On the other hand, even if the width of the combustion chamber hole outer edge portion 8 is narrowed by extending the end portion 6 of the folded portion 5 until it is located in the recess of the combustion chamber hole side bead 2, the combustion chamber hole outer edge portion 8 Therefore, it is possible to reliably generate a high surface pressure at the outer edge 8 of the combustion chamber hole.

  Moreover, even if the seal surface width S is narrowed by extending the end portion 6 of the folded portion 5 until it is located in the recess of the combustion chamber hole side bead 2, a predetermined folded width is ensured. As a result, it is possible to avoid the difficulty of turning back. This also allows the bead width to be freely designed even under a narrow seal surface width S.

  (3) In the present embodiment, the first region R1 having the greatest thickness is positioned from the end of the combustion chamber hole 7 into the recess of the combustion chamber hole bead 2. For this reason, the combustion chamber hole side bead 2 generates a spring force in a substantially fully bent state at the corner 2a (the corner 2a in the first region R1) on the combustion chamber hole 7 side by bolt tightening. On the other hand, at the corner 2b on the cooling water hole 13 side (corner 2b in the second region R2), the plate thickness difference between the first region R1 and the second region R2 (the thickness of the sub-plate 4) floats. A spring force is generated in the state.

For this reason, the combustion chamber hole-side bead 2 has a repulsive latent spring force on the corner 2b (the corner 2b in the second region R2) on the cooling water hole 13 side. Due to this repulsive latent spring force, the high temperature and high pressure gas generated by pulsation due to the explosion in the combustion chamber 10 improves the deformation followability with respect to expansion / contraction between the joint surfaces and further improves the sealing performance.
Further details. A vibration amplitude is generated between the cylinder block 11 and the cylinder head 12 due to the explosion in the combustion chamber 10 during engine operation. At this time, the repulsive force of the gasket also cooperates, and although it is minute, the expansion and contraction are repeated, and the surface pressure decreases instantaneously at the time of expansion. The repulsive latent spring force follows the expansion deformation that is the cause of the decrease, and the decrease in surface pressure is minimized.

  In addition, since the folding | returning part 5 of the said structure is not provided in the convex side of the combustion chamber hole side bead 2, the stopper function which controls the compression deformation of the convex part of the combustion chamber hole side bead 2 is not small. On the other hand, when turning back to the convex side of the combustion chamber hole side bead 2, the compressive deformation of the convex portion is restricted, and the bead surface pressure is attenuated by the plate thickness of the sub plate 4, so the bead height is increased accordingly. However, in this embodiment, it is not necessary to increase the bead height by the restriction amount.

  (4) Since the outer peripheral edge 16 of the sub-plate 4 is disposed in the cooling water region W / J, the outer peripheral end of the sub-plate 4 even if a gasket is disposed between the opposing joining surfaces. It is possible to prevent a large load from being applied. Further, by arranging the end portion 6 of the folded portion 5 of the sub-plate 4 in the recess of the combustion chamber hole side bead 2, it is possible to reduce applying a large load to the end portion 6 of the folded portion 5 of the sub-plate 4. ing. As a result, the joint surface is prevented from being wrinkled as much as possible at the corners of the end portions 16 and 6 of the sub-plate 4.

(Modification)
(1) Here, FIG. 2 illustrates the case where the combustion chamber hole bead 2 surrounding the combustion chamber hole 7 is single, but as shown in FIG. 3, the combustion chamber hole bead 2 is double. It may be the case. In FIG. 3, the case where the combustion chamber hole side bead 2 of an outer peripheral side is formed with a half bead is illustrated. And the case where the edge part 6 of the folding | turning part 5 is arrange | positioned in the recessed part of the combustion chamber hole side bead 2 which consists of an inner peripheral side full bead is illustrated.

(2) FIG. 4 illustrates the case where two substrates 1 are stacked. In this example, two substrates 1 are arranged with the concave side of the combustion chamber hole side bead 2 facing each other, and the sub-plate 4 having the above-described configuration is arranged between the two substrates 1.
Here, the two substrates 1 may be arranged with the convex portion side of the combustion chamber hole side bead 2 facing each other. In this case, the sub-plate 4 having the above configuration may be disposed on the concave 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 parts as those in the first embodiment will be described with the same reference numerals.

(Constitution)
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 arranged on the convex side of the combustion chamber hole side bead 2 as shown in FIG. .
That is, the sub plate 4 faces the surface (upper surface) of the convex portion side of the combustion chamber hole side bead 2 of the substrate 1. And the sub-plate 4 is arranged at a position where the outer peripheral side end overlaps the cooling water region W / J, and extends from the position overlapping the cooling water region W / J to the end of the combustion chamber hole 7 side, Further, the folded portion 5 is formed by folding downward at the end portion on the combustion chamber hole 7 side so as to sandwich the combustion chamber hole outer edge portion 8 of the substrate 1. And the edge part 6 of the folding | returning part 5 of the subplate 4 is arrange | positioned so that it may be located in the recessed part of the said combustion chamber hole side bead 2. FIG.

However, in the configuration of FIG. 5, the shape of the sub-plate 4 is set along the shape of the substrate 1 including the folded portion 5 so that the sub-plate 4 is in contact with the surface of the substrate 1 as much as possible. In other words, the portion facing the convex portion of the combustion chamber hole side bead 2 has a convex shape upward like the convex portion of the combustion chamber hole side bead 2. Moreover, the part facing the recessed part of the combustion chamber hole side bead 2 in the folding | turning part 5 is also deform | transforming upwards along the concave surface.
Other configurations are the same as those in the first embodiment.

(Function and effect)
(1) The same operational effects as in the first embodiment can be generated.
(2) Give the sub-plate 4 a shape portion along the convex portion and the concave portion of the combustion chamber hole side bead 2. Thereby, the shift of the sub plate 4 with respect to the substrate 1 is reduced.
The sub-plate 4 does not have to be an elastic metal body. When the sub plate 4 is an elastic metal body, the spring force of the combustion chamber hole side bead 2 can be increased correspondingly by the spring of the sub plate 4.

(Modification)
(1) The case where the combustion chamber hole side bead 2 is formed of a half bead is shown in FIG. The combustion chamber hole side bead 2 made of this step-shaped half bead is bent and formed so as to protrude upward with the combustion chamber hole outer edge portion 8 as a reference, forming a convex on the upper side and forming a concave on the lower side. .
As described above, the sub-plate 4 extends along the upper surface of the substrate 1, which is the convex side of the combustion chamber hole bead 2, and the combustion chamber hole outer edge of the substrate 1 at the end of the combustion chamber hole 7. The folded portion 5 is formed by folding downward so as to sandwich 8. And the edge part 6 of the folding | returning part 5 of the subplate 4 is arrange | positioned so that it may be located in the recessed part of the said combustion chamber hole side bead 2. FIG.
The effect is the same as above.

(2) The case where two substrates 1 are provided is illustrated in FIGS. In this example, two substrates 1 are arranged with the concave portion of the combustion chamber hole side bead 2 facing each other, and the sub-plate 4 having the above-described configuration is interposed with respect to one of the two substrates 1. This is an example. The effect is the same as above.
Note that the two substrates 1 may be arranged with the convex portions of the combustion chamber hole side beads 2 facing each other.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to the drawings. Components similar to those in the above embodiments will be described with the same reference numerals.

(Constitution)
The basic configuration of the third embodiment is the same as that of the first embodiment. As shown in FIG. 9, the sub-plate 4 is arranged so as to face the surface of the substrate 1 on the concave portion side.
However, the point which forms the bead which consists of a full bead which protrudes in the said recessed part in the part which opposes the recessed part of the combustion chamber hole side bead 2 in the subplate 4 differs from 1st Embodiment. Moreover, the subplate 4 is comprised from an elastic metal plate.
Other configurations are the same as those in the first embodiment.

(Function and effect)
(1) The same operational effects as in the first embodiment can be generated.
(2) When the combustion chamber hole side bead 2 made of a full bead molded on the substrate 1 is compressed and deformed, the rising portion (corner portions 2a, 2b) on the concave side has a small and high area in contact with the lower joint surface Pressure is generated. On the other hand, the convex side of the combustion chamber hole-side bead 2 having a circular arc cross section is in contact with the upper joint surface at the R portion, so that the contact area is wide, and the surface pressure per unit is weaker than the corners 2a and 2b.
By arranging the bead of the sub-plate 4 below the convex surface side, the surface pressure on the convex surface side of the cross-section arc shape in the combustion chamber hole-side bead 2 is gained by the spring force of the bead of the sub-plate 4. Thus, the sealing performance for the upper joint surface is increased.

  That is, when the gasket is mounted on the engine and fastened with a tightening bolt, the combustion chamber hole side bead 2 located in the first region R1 and the bead of the sub-plate 4 are deformed almost fully bent. Both the side bead 2 and the bead molded on the sub-plate 4 hold repulsive energy. With this repulsive energy, it follows a minute gap that instantly opens due to repeated expansion and contraction during engine operation. Further, the convex side of the substrate 1 bead having a large grounding area on the sealing surface has a lower bonding surface pressure than the grounding on the concave side, but it is supplemented by the sub-plate 4 bead.

(Modification)
(1) FIG. 10 illustrates the case where there are two substrates 1. In this example, two substrates 1 are arranged with the concave side of the combustion chamber hole side bead 2 facing each other, and the sub-plate 4 having the above-described configuration is arranged between the two substrates 1.
Here, the two substrates 1 may be arranged with the convex portion side of the combustion chamber hole side bead 2 facing each other. In this case, the sub-plate 4 having the above configuration may be disposed on the concave side of one of the two substrates 1.

(2) Here, in all the embodiments, the case where the end portion 6 of the folded portion 5 of the sub-plate 4 is set so as to be positioned in the recess of the combustion chamber hole side bead 2 is illustrated.
However, the end portion 6 of the folded 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.
An example is shown in FIG. In this example, the sub-plate 4 is arranged on the concave portion side of the combustion chamber hole side bead 2 and folded upward so as to sandwich the substrate 1 at the end portion on the combustion chamber hole 7 side, and the end portion 6 of the folded portion 5 is replaced with the combustion chamber. It arrange | positions in the middle position of the convex surface of the convex part of the hole side bead 2.

Further, in this example, the portion of the sub-plate 4 located on the convex portion side of the combustion chamber hole side bead 2, that is, one surface side of the substrate 1, has a shape along the shape of the surface of the opposing substrate. Thereby, even if a deviation occurs due to a difference in thermal expansion between the engine and the gasket material, the deviation between the substrate 1 and the sub plate 4 can be reduced.
Further, in this example, the portion of the sub-plate 4 located on the recess side of the combustion chamber hole side bead 2, that is, on the other surface side of the substrate 1 is also shaped along the shape of the surface of the opposing substrate. Thereby, even if a deviation occurs due to a difference in thermal expansion between the engine and the gasket material, the deviation between the substrate 1 and the sub plate 4 can be further reduced.

In this case, it is preferable to round the corner of the end portion 6 of the folded portion 5 or to gradually reduce the thickness toward the tip.
Moreover, it is preferable to set the position of the end portion 6 of the folded-back portion 5 to a position where the convex top 2d of the combustion chamber hole side bead 2 is removed. In particular, the combustion chamber hole 7 side is more preferable than the convex top 2d of the combustion chamber hole side bead 2. In particular, the height of the end portion 6 of the folded portion 5 is preferably as high as the convex portion top portion 2d of the combustion chamber hole side bead 2 or less.

(3) In all the embodiments, by providing the folded portion 5 on the sub-plate 4, the thickness of the gasket is set to change in three stages from the combustion chamber hole 7 to the outer periphery. It is not limited. Instead of forming the folded portion 5 of the sub-plate 4 in the portion corresponding to the first region R1, the above-described configuration may be achieved by stacking and fixing shim plates. FIG. 12 shows an example in which the folded portion 5 is formed by another plate and fixed by welding or the like.
Or you may make it achieve the said structure by adjusting the thickness of the board | substrate 1 or the subplate 4 itself.

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Combustion chamber hole side bead 2a, 2b Corner | angular part 2c Protrusion part 4 Subplate 5 Folding part 6 End part of folding | turning part 7 Combustion chamber hole 8 Combustion chamber hole outer edge part 9 Subplate bead 10 Combustion chamber 11 Cylinder block 12 Cylinder head 13 Cooling water hole 15 Bolt hole 16 Outer peripheral edge 20 of sub-plate Metal gasket R1 First region R2 Second region R3 Third region S Seal surface width W / J Cooling water region

Claims (3)

A metal gasket interposed between a joint surface of a cylinder block having a cooling water region formed on a combustion chamber and an outer peripheral side thereof through which cooling water passes, and a joint surface of a cylinder head,
One or two or more substrates and a sub-plate are laminated,
The substrate includes a combustion chamber hole that opens to a position corresponding to the combustion chamber, a combustion chamber hole outer edge continuous to the combustion chamber hole, and a combustion chamber hole side bead that surrounds the combustion chamber hole and the combustion chamber hole outer edge. And comprising
The metal gasket has a first region from the combustion chamber hole end to the middle position in the width direction of the combustion chamber hole side bead from the combustion chamber hole side toward the gasket outer peripheral side, and a middle position in the width direction of the combustion chamber hole side bead. Is divided into three regions, a second region from the middle of the position overlapping with the inside of the cooling water region, a third region on the outer peripheral side of the second region,
The sub-plate is configured such that the outer peripheral side end portion is disposed at a position overlapping the inside of the cooling water region, extends to the combustion chamber hole side, and is folded back so as to sandwich the combustion chamber hole outer edge portion on the combustion chamber hole side. By arranging the end of the folded portion of the sub plate at a position overlapping the combustion chamber hole side bead, the thickness of the metal gasket is the largest in the first region and the second region is the next. It is thick and the third region is the thinnest,
The portion of the sub-plate facing the combustion chamber hole side bead is shaped along the shape of the surface of the one opposing substrate and is in contact with the combustion chamber hole bead of the one substrate. Characteristic metal gasket. The combustion chamber hole side bead is formed by bending a metal plate constituting the substrate so as to be convex toward one surface side of the substrate, with the outer edge of the combustion chamber hole as a reference, and at each end of the bead width. A corner of the bead extending along the outer periphery of the combustion chamber hole is formed,
The end portion of the folded portion of the sub-plate is located between the corner portions of the two beads arranged in the width direction, and the folded portion is disposed on the other surface side of the substrate. Item 1. A metal gasket according to Item 1. The combustion chamber hole side bead is formed by bending a metal plate constituting the substrate so as to be convex toward one surface side of the substrate, with the outer edge of the combustion chamber hole as a reference, and at each end of the bead width. A corner of the bead extending along the outer periphery of the combustion chamber hole is formed,
The end portion of the folded portion of the sub-plate is located between the corner portions of two beads arranged in the width direction, and the folded portion is disposed on one surface side of the substrate. The metal gasket described in 1.

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