JP3343468B2 - Metal gasket - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal gasket interposed between opposed parts of a multi-cylinder engine for sealing between the parts.

[0002]

2. Description of the Related Art Conventionally, structural members of an engine such as a cylinder head and a cylinder block made of an aluminum alloy are lightweight, but have low rigidity, so that a relative displacement between the two tends to increase during engine operation. Therefore, the metal gasket for sealing between the opposed mounting surfaces of the two structural members is made of an elastic metal plate having a bead formed in the vicinity of a cylinder bore, that is, a through hole corresponding to a passage for a combustion chamber, water, oil, or the like. I have.

[0003] Conventionally, a metal gasket made of a metal material has been used to seal between opposing surfaces between a cylinder head and a cylinder block in an engine. The metal gasket has a bead near the periphery of a through-hole corresponding to a cylinder bore, water and oil passages. When the cylinder head and the cylinder block are fastened and fixed with bolts or the like, the bead is opposed to the opposed surface. Form an elastic annular contact portion to seal between opposing surfaces.

[0004] However, recent engines are required to have higher output and lighter weight. As a part of this, as a part of the trend, cylinder heads and cylinder blocks have tended to be manufactured from aluminum alloy having low specific gravity in place of conventional steel or casting having high specific gravity. It is in. Aluminum alloys are lightweight but have low rigidity, so the relative displacement of the cylinder head with respect to the cylinder block during operation of the engine tends to increase.
When tightening the opposing surfaces of the cylinder head and the cylinder block with tightening bolts through a single-plate metal gasket, the positions of the tightening bolts are dispersed on the outer periphery of the metal gasket or relatively on the outer periphery. Since the combustion chamber holes are not always evenly distributed around the periphery, the facing surface is likely to be irregular. As a result, high-temperature and high-pressure combustion gas intrudes into the opposing surface of a highly distorted portion such as the portion between the combustion chamber holes, and corrodes and contaminates the metal gasket bead interposed between the opposing surfaces. Decreases sealing effect.

Further, in the case of a cylinder head gasket, the distance between the cylinder head and the cylinder block repeatedly increases and decreases during the combustion cycle of the engine, and mechanical stress or thermal stress acts on the metal gasket repeatedly. The load fluctuation stress of the engine is
This occurs as a large value at the lowest rigidity portion of the cylinder block or cylinder head, and as a result, there occurs a problem that the bead is set or a crack is generated to deteriorate the sealing performance.

A metal gasket disclosed in Japanese Patent Application Laid-Open No. 5-39868 is constituted by laminating a first elastic metal plate having a bead and a folded portion and a second elastic metal plate having a bead. The beads are in contact with each other. The metal gasket absorbs irregularities by disposing the beads of two elastic metal plates in series, even if irregularities occur between the two opposing surfaces during tightening, in response to the distortion. In addition, when used after tightening, it shares the fluctuating load due to the repetition of the combustion cycle of the internal combustion engine, reducing the amount of cylinder head distortion,
The followability to the movement of the cylinder head is improved, and the bead is prevented from being fully compressed to maintain a high sealing effect.
The folded portion of the elastic metal plate prevents bead corrosion and fouling due to the intrusion of high-temperature, high-pressure combustion gas, and causes bead settling and cracking due to large fluctuating load stress generated in the least rigid part of the cylinder head. Instead, the combination of the thicknesses of the two elastic metal plates and the formation of the folded portion can exert a stopper function, reduce the load stress at the bead position, and improve the durability.

[0007]

However, a metal gasket made of an elastic metal plate having a folded portion is very expensive for forming the folded portion on the elastic metal plate because the folded portion is formed in the elastic metal plate. It is necessary to use a material which is required to have high processing accuracy and has good workability of the folded portion, for example, a material having a high elongation, a low hardness and a low tensile strength. Alternatively, in order to form the folded portion on the elastic metal plate, it is necessary to heat-treat the elastic metal plate after forming the folded portion on the elastic metal plate to increase the material strength, and it is necessary to use an expensive material and to process the material. Becomes complicated and the cost increases. In addition, since the degree of processing of the folded portion on the elastic metal plate is high, there is a problem that a crack is easily generated in the folded portion.

Further, in the metal gasket, the thickness of the elastic metal plate having the folded portion is added to the thickness of the folded portion as it is, so that the area around the combustion chamber and other areas are different.
The thickness difference becomes large, the selection of the thickness of the elastic metal plate is restricted in terms of the balance of the surface pressure, and the degree of freedom in design is reduced. For example, the thickness of the elastic metal plate is 0.10 to 0.15 mm. Is the limit. Therefore, in the metal gasket, when the folded portion is formed, the surface pressure around the combustion chamber hole tends to concentrate, so that even if the folded portion is composed of two pieces, it is compressed to 1.5 pieces.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a pair of bead substrates made of an elastic metal plate each having a bead formed along a parallel hole, and disposing the beads facing each other, Stopper beads are formed on the hole side of the bead so as to face each other along the hole so as not to overlap each other, and the height of the stopper bead formed on the bead substrate is formed lower than the height of the bead. The stopper bead contacts the opposing bead substrate to form a seal line around the hole, thereby preventing the bead substrate from being fully compressed and a dead line formed between the bead substrates. An object of the present invention is to provide a metal gasket capable of reducing a space.

The present invention has a pair of bead substrates formed of elastic metal plates each having a bead formed along a parallel hole, wherein the bead substrates are arranged such that the beads are opposed to each other, and the bead substrate has Stopper beads are formed on the hole side of the bead so as not to overlap with each other along the hole, and the stopper bead formed on the bead substrate has a lower height and a bead width than the bead. The stopper bead is formed to be small, and the stopper bead contacts the opposing bead substrate to form a seal line around the hole, prevents the bead from being fully compressed, and is formed between the bead substrates. The present invention relates to a metal gasket for reducing dead space.

The top surface of the bead formed on the bead substrate is formed as a convex surface, and the respective convex surfaces are in contact with each other. Alternatively, in this metal gasket, the top surface of the bead formed on one bead substrate of the bead substrate is formed in an uneven plane, and the convex surface of the top surface of the bead of the other bead substrate is formed on the uneven plane. That is in contact. If the top surface of the bead is formed in an uneven plane, the bead can be stably installed on the other side, the function of the bead can be stabilized, and a highly reliable sealing function can be achieved.

In the metal gasket, a half bead is formed on one of the bead substrates along an edge of the hole, and the stopper bead formed on the other bead substrate is provided with the one of the bead substrates. It is located between the stopper bead formed on the bead substrate and the half bead.

In the metal gasket, the beads formed on one bead substrate of the bead substrates are formed in two pieces, that is, two strips at intervals along the hole, and the bead substrate is formed with two beads. A bead is located between the beads on the one bead substrate. Further, a flat surface is formed between the beads formed spaced apart from the one bead substrate, and the bead of the other bead substrate is in contact with the flat surface.

This metal gasket is, as described above,
Forming a stopper bead projecting to a height less than the height of the bead toward the bead substrate facing the bead substrate may further reduce a dead space formed between the bead substrates by the stopper bead. In addition, the stopper bead can prevent gas from entering the bead, improve sealing performance, and prevent the bead from settling and cracking. In addition, this metal gasket can be constituted by two bead substrates by providing the stopper beads on the bead substrate, thereby reducing the number of layers and the number of parts.

[0015] When a half bead projecting to a height less than the height of the bead toward the bead substrate facing the bead substrate is formed, the half bead performs a function of blocking high-temperature gas from the stopper bead and the bead, The half bead can prevent gas from entering the stopper bead, prevent settling or cracking of the stopper bead and the bead, and improve the durability of the stopper bead and the bead.

Therefore, this metal gasket prevents and protects the bead from being fully compressed by forming a stopper bead on the bead substrate provided with a bead made of two elastic metal plates, and protects the bead. The sealing performance can be ensured, the function of the bead is always exerted properly, the stopper bead performs the sealing function for the bead, the durability of the bead is improved, and the space member and the intermediate plate as in the prior art are required. And the number of parts can be reduced,
It is inexpensive and can increase reliability. In some cases,
By forming a half bead on one bead substrate, it is possible to prevent combustion gas from entering the stopper bead.
The durability between the stopper bead and the bead can be improved.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a metal gasket according to the present invention will be described. Although not shown, the metal gasket is preferably applied to a head gasket sandwiched between a cylinder head and a cylinder block to seal between opposing surfaces. In this metal gasket, combustion chamber holes, that is, holes are formed in parallel with cylinder bores formed in the cylinder block. This metal gasket has a plurality of holes formed in parallel so that it can be applied to a multi-cylinder engine such as a four-cylinder or six-cylinder engine. In the drawings showing the embodiments described below, the same reference numerals denote parts and portions having the same configuration and the same function, and the same reference numerals will be given, and redundant description will be omitted.

First, a metal gasket according to the present invention will be described with reference to FIGS. FIG. 1 is a partial plan view showing an embodiment of a metal gasket according to the present invention, FIG. 2 is an enlarged plan view of one bead substrate of the metal gasket of FIG. 4 is an enlarged plan view of the other bead substrate at symbol C, FIG. 4 is a cross-sectional view showing one embodiment of the metal gasket of FIG. 1 along line AA, and FIG. 5 is a line B- of the metal gasket of FIG. It is sectional drawing which shows one Example in B.

The metal gasket comprises a bead substrate 1 made of an elastic metal plate having combustion chamber holes, ie, holes 7, corresponding to combustion chambers formed in parallel in a multi-cylinder engine.
2 is comprised. A plurality of bolt holes 12, water holes 13, blow-by holes 14, knock holes, and oil holes 16 are formed around the holes 7 in the bead substrates 1 and 2.
Beads 3 and 4 having a convex cross section are formed on the bead substrates 1 and 2 so as to surround the holes 7 substantially concentrically and annularly along the holes 7 formed in the bead substrates 1 and 2. Bead boards 1, 2
Are arranged such that beads 3 and 4 face each other and are stacked. Each of the beads 3 and 4 has a convex surface 17 formed on the top surface thereof, and the convex surfaces 17 are arranged so as to face each other and be in contact with each other.

In this metal gasket, the bead substrates 1 and 2 are provided with the beads 3 and 4 in the same direction as the protrusions of the beads 3 and 4 along the hole 7 on the hole 7 side from the beads 3 and 4.
Stopper beads 5 and 6 projecting below the height of 4 are formed. Further, the stopper beads 5, 6 are formed to face each other so as not to overlap each other.
In other words, the stopper beads 5, 6 extend along the hole 7 in an area which is displaced from one another at a position different from the bore, that is, the distance from the hole 7. Therefore, the stopper beads 5, 6
Are arranged so as to contact the flat surfaces 21 and 22 of the opposing bead substrates 1 and 2. In the beads 3 and 4 formed on the bead substrates 1 and 2, the adjacent beads 3 and 4 in the region between the holes 7 are associated with each other to form a single association bead 20. The stopper beads 5 and 6 formed on the bead substrates 1 and 2 are formed independently of each other in the region between the holes 7 without the adjacent stopper beads 5 and 6 being associated with each other. As shown in FIG. 5, the bead substrates 1 and 2 are in close contact with each other in a region D on the peripheral edge of the metal gasket.

In this metal gasket, a triple seal line is formed at the three positions of the beads 3, 4, the stopper bead 5, and the stopper bead 6 by the above configuration, and a very strong sealing structure is formed. The stopper beads 5 and 6 formed on the bead substrates 1 and 2 are formed to have a lower height and a smaller bead width than the beads 3 and 4, have a higher rigidity than the beads 3 and 4, and have a higher bead. As a result, the beads 3 and 4 perform a stopper function for preventing the beads 3 and 4 from being fully compressed. Further, in the metal gasket, since the stopper beads 5 and 6 have high rigidity, irregularities between the contact surfaces can be absorbed when tightened between the cylinder head and the cylinder block.

In this metal gasket, the bead substrates 1 and 2 can be formed to have the same thickness within a range of, for example, 0.2 to 0.3 mm. The thicknesses of the bead substrates 1 and 2 can be changed from each other in consideration of the positional relationship between the cylinder block and the cylinder head. Further, the height of the stopper beads 5 and 6 formed on the bead substrates 1 and 2 is
Can be appropriately changed to each other for the adjustment of the surface pressure generated in the above. By changing the thickness of the bead substrates 1 and 2 and the height of the stopper beads 5 and 6, the degree of freedom in combination and design is increased. Further, the height of the beads 3 and 4 formed on the bead substrates 1 and 2 can be increased in the region between the bores, that is, between the holes 7, and can be reduced in other regions. When the metal gasket is tightened between the cylinder block and the cylinder head, the surface pressure generated by the beads 3, 4 and the stopper beads 5, 6 is adjusted to the height and plate thickness so as to conform to the rigidity of the cylinder head. By changing it, it is possible to control to an appropriate surface pressure.

In this metal gasket, for example, the bead substrates 1 and 2 are made of SUS301. As shown in FIG. 11, a heat-resistant and oil-resistant nonmetal layer is coated on the surface of the elastic metal plate forming the bead substrates 1 and 2 to a thickness of, for example, about 10 to 50 μm, and the cylinder head and the cylinder block are formed. In contrast, a metal-to-metal contact state is avoided, and the corrosion resistance, durability and strength of a metal gasket are secured. For example, both sides of the bead substrate 1 and the lower surface of the bead substrate 2 are coated with a fluorine rubber 10 having heat resistance and oil resistance,
Further, an acrylic silicone resin 11
Is coated. The non-metal layer coated on the surfaces of the bead substrates 1 and 2 can cover the irregularities and perform a sufficient sealing function even if irregularities are present during machining of the opposing surfaces.

Next, another embodiment of the metal gasket according to the present invention will be described with reference to FIGS. In this embodiment, the top surface of a bead 8 formed on one bead substrate 2 is formed on an uneven surface 18, and the convex surface 17 on the top surface of a bead 3 of the other bead substrate 1 is in contact with the uneven surface 18. .
If the top surface of the bead 8 formed on the bead substrate 2 is formed on the uneven surface 18, the convex surface 17 on the top surface of the bead 3 of the bead substrate 1 can stably contact the uneven surface 18 to operate. The surface pressure of the beads 3 and 8 is stabilized, and the sealing function is stabilized. In this embodiment, as in the above-described embodiment, triple seal lines are formed at three places of the beads 3, 8, the stopper bead 5, and the stopper bead 6, and an extremely strong seal structure is formed.

Next, another embodiment of the metal gasket according to the present invention will be described with reference to FIGS.
In this embodiment, a half bead 9 is formed on one bead substrate 2 along the edge of the hole 7. The stopper bead 5 of the other bead substrate 3 is arranged between the half bead 9 formed on one bead substrate 2 and the stopper bead 6. In this metal gasket, the formation of the half bead 9 on the bead substrate 2 increases the number of seals, forms a quadruple seal line at four places, forms an extremely strong seal structure, and further stabilizes the seal function. Can be changed.

Next, another embodiment of the metal gasket according to the present invention will be described with reference to FIG. In this embodiment, beads 3A and 3B formed on one bead substrate 1 are formed.
Are formed at intervals along the hole 7, and the beads 4 of the other bead substrate 2 are separated from the beads 3 </ b> A and 3 </ b> A of the bead substrate 1.
B. Further, a flat surface 19 is formed between the bead 3A and the bead 3B formed apart from the bead substrate 1, and the bead 4 of the bead substrate 2 is in contact with the flat surface 19. Beads 3A and 3B on bead substrate 1
Is formed, the bead 4 of the other bead substrate 2 can stably perform a sealing function between the beads 3A and 3B. By forming two beads 3A and 3B on the bead substrate 1, the number of seals increases, five-fold seal lines are formed at five places, an extremely strong seal structure is formed, and the seal function is further stabilized. Can be done.
Moreover, in this embodiment, the beads 3A, 3B, 4 and the stopper beads 5, 6 independently contact the flat surfaces 19, 21, 22 of the opposing bead substrates 1, 2, respectively.
The surface pressure adjustment that occurs in each case can be set appropriately.

[0027]

According to the metal gasket of the present invention, since the beads and the stopper beads are formed on the bead substrate as described above, the stopper beads further increase the dead space near the hole formed between the bead substrates. The sealability can be improved by forming multiple seal lines, the gas can be prevented from entering the bead, and the bead can be prevented from being set or cracked due to gas corrosion. In addition, the stopper bead functions as a stopper to prevent the compression of the bead from being completely compressed, thereby preventing the bead from setting. By providing the stopper bead, this metal gasket can perform the same sealing function and surface pressure adjusting function as those formed with the conventional folded portion, and has less material restrictions than the folded portion. Therefore, the manufacturing cost can be reduced and the durability can be greatly improved.

That is, the stopper beads formed on both the bead substrates prevent the beads from being completely compressed, absorb the irregularity of the opposing surfaces of the cylinder head and the cylinder block, and provide a sealing function for protecting the beads. A compensating portion having a bead is formed to prevent the bead from settling or cracking by preventing the bead from being over-compressed. The stopper bead blocks the inflow of the combustion gas to the bead side to prevent the bead from becoming hot. The bead is protected from corrosion and the like, and the function of the bead is prevented from deteriorating.

This metal gasket does not use a separate member such as a spacer to form a compensating portion, does not require the manufacture of a separate member, can be composed of only a pair of the bead substrates, and has a reduced number of parts. Since the number of machining steps can be reduced, the number of machining steps can be reduced, and the machining shape is simple, not only can the manufacturing cost be significantly reduced, but also the machining accuracy of parts can be increased, accumulated errors can be reduced, and the height of the stopper bead can be reduced. Control becomes easier, the sealing performance is improved by reducing the number of layers, and a highly reliable product can be provided. In addition, since the stopper bead forms the compensating portion, the folded portion is not formed at the hole side edge of the bead substrate without forming the folded portion. Therefore, the manufacturing process of forming the folded portion is omitted. It is not necessary, and it is not necessary to take a countermeasure that a crack is generated in the folded portion, and the manufacturing cost can be reduced.

In this metal gasket, the height of the stopper bead, the bead, and the half bead of the bead substrate can be arbitrarily set by setting, so that the surface pressure balance between the opposing surfaces of the two bead substrates is also reduced. It can be adjusted properly. There is a margin that the stress fluctuation of the bead substrate and the bending stress applied to the compensator can be set according to a situation such as when there is a difference in the characteristics of the bead substrate. This prevents damage to the compensator, damage to the compensator, and a reduction in the sealing effect, thereby achieving a stable sealing effect.

[Brief description of the drawings]

FIG. 1 is a partial plan view showing one embodiment of a metal gasket according to the present invention.

FIG. 2 is an enlarged plan view of one bead substrate of the metal gasket of FIG.

FIG. 3 is an enlarged plan view of the other bead substrate of the metal gasket of FIG.

FIG. 4 is a cross-sectional view showing one embodiment of the metal gasket of FIG. 1 along line AA.

FIG. 5 is a sectional view showing one embodiment of the metal gasket of FIG. 1 taken along line BB.

FIG. 6 is a cross-sectional view showing another embodiment of the metal gasket of FIG. 1 along line AA.

FIG. 7 is a cross-sectional view showing another embodiment of the metal gasket of FIG. 1 taken along line BB.

FIG. 8 is a sectional view showing still another embodiment of the metal gasket of FIG. 1 along line AA.

FIG. 9 is a sectional view showing still another embodiment of the metal gasket of FIG. 1 taken along line BB.

FIG. 10 is a cross-sectional view showing another example of the metal gasket of FIG. 1 along line AA.

FIG. 11 is a partial sectional view showing a sectional structure of a pair of bead substrates of the metal gasket of FIG. 1;

[Explanation of symbols]

 1, 2 bead substrate 3, 3A, 3B, 4, 8 bead 5, 6 stopper bead 7 hole 9 half bead 17 convex surface 18 deflected plane 19, 21, 22 flat surface

Continuation of the front page (56) References JP-A-63-101575 (JP, A) JP-A-5-52268 (JP, A) JP-A-63-84462 (JP, U) JP-A-2-67161 (JP) , U) Hikaru Hei 3-57558 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16J 15/08

Claims (6)

(57) [Claims] A pair of bead substrates each comprising an elastic metal plate having beads formed along parallel holes, wherein the bead substrates are arranged such that the beads are opposed to each other;
A stopper bead is formed on the bead substrate on the hole side of the bead along the hole so as not to overlap each other, and the stopper bead formed on the bead substrate has a height higher than the bead. Low and bee
The stopper bead is opposed
A seal line is formed around the hole in contact with the bead substrate.
Forming and compressing the entire bead of the bead substrate.
To prevent dead spots formed between the bead substrates.
Metal gasket consisting of reducing pace . 2. A top surface of the bead formed on the bead substrate is formed on the convex surface, the metal gasket according to claim 1 which comprises each of the convex surface is in contact with one another. 3. The method according to claim 1, wherein a top surface of the bead formed on one bead substrate of the bead substrate is formed as a depressed plane, and a convex surface of a top surface of the bead of the other bead substrate is brought into contact with the deviated plane. The metal gasket according to claim 1, comprising : Wherein said bead one bead plate of the substrate half bead is formed along the edge of the hole, the other
The stopper bead formed on one of the bead substrates is
The stopper bead formed on one bead substrate and the stopper bead
The metal gasket according to claim 1, wherein the metal gasket is located between the half bead and the half bead . 5. The bead formed on one bead substrate among the bead substrates is formed in two rows at intervals along the hole, and the bead on the other bead substrate is formed on the one bead substrate on the one bead substrate. metal gasket according to any one of <br/> claims 1-4 which consists in being located between the beads. 6. A flat surface is formed between the bead the formed by spaced one bead plate, said beads of the other bead plate to the flat surface is in contact with The metal gasket according to claim 5 , comprising: