JPH0532872U - Metal gasket with elastic part - Google Patents

Abstract

(57) [Summary] [Purpose] A bead in contact with the joint surface, and a gasket with a structure that folds back to the protruding side of the bead at the periphery of the hole to seal.
(EN) Provided is a metal gasket that prevents the occurrence of cracks around a folded portion due to a difference in thermal expansion from a joint surface. [Structure] A thin metal plate 2 is folded back at a week edge of a seal hole 4 to form a folded portion 6 surrounding the seal hole, and a gap is provided between an outer peripheral edge 8 of the folded portion 6 and an opening 18 of a thickness adjusting plate 12. Δ
And the elastic portion 10 was formed on the thin metal plate 2 in the gap Δ portion.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a metal gasket having a stretchable part made of a thin metal plate.

[0002]

[Prior Art]

 For example, a metal gasket such as a head gasket of an internal combustion engine has conventionally been provided with a bead on a gasket component plate made of a thin metal plate having elasticity, or a wire ring is provided to seal a periphery of a seal hole such as a combustion chamber hole. The surface pressure for sealing is generated, and one surface plate is folded back to the other side at the periphery of the seal hole to cover the beads and wire ring so that fluid does not enter the inside of the gasket. ing. It is well known that the bead and wire ring are compressed and elastically deformed, and the repulsive force causes the bonded surfaces to come into close contact with each other to generate sealing performance.

[0003]

[Problems to be solved by the device]

 By the way, for example, when a high-performance internal combustion engine made of aluminum alloy has a high combustion pressure and a large head bolt tightening force, and the temperature difference between use and non-use is large, the thermal expansion of the cylinder head The contraction increases, and the difference between expansion and contraction of gaskets made of different materials increases. In the structure in which the bead or wire ring is covered with the folded plate, since the portion is pressed against the joint surface with a strong force, it becomes difficult for the surface plate to slide on the joint surface, and a tear force is generated in the portion. To do. Under such conditions, if the gasket is used for a long period of time and the mechanical strength of the thin metal plate deteriorates due to thermal fatigue and metal fatigue, and the strength becomes less than the above-mentioned tearing strength, cracks will occur around the folded part. There's a problem.

The present invention has been made in view of the above problem, and in a metal gasket having a structure in which a sealing means such as a bead is covered with the periphery of a hole to be sealed and folded back on the opposite side, an object to be sealed with the gasket is It is an object of the present invention to provide a metal gasket having a stretchable portion that prevents cracks from being generated around the folded-back portion due to a difference in thermal expansion between the member and the like.

[0005]

[Means for Solving the Problems]

 In order to achieve the above object, the metal gasket having an expandable portion of the present invention has one surface plate made of laminated metal thin plates folded back at the peripheral edge of the seal hole to form a folded part surrounding the seal hole. A thickness adjusting plate made of a thin metal plate is laminated on the face plate, and the thickness adjusting plate is provided with an opening surrounding the hole to be sealed, and the opening is provided with a ring-shaped gap between the opening and the outer peripheral edge of the folded portion. An expansion / contraction portion formed of a groove that surrounds a hole for sealing is formed on the surface plate in the gap portion.

The cross-sectional shape of the expansion / contraction part is not particularly limited. For example, one or a plurality of corrugated parts having a corrugated shape, a trapezoidal shape, or the like has been used as a conventional bead. The shape described can be appropriately used. Further, the stretchable portion can be formed in a meandering shape. Since the total plate thickness of the part is thin, the compressive force of the expandable part is lower than that of the other parts, and the expandable part can expand and contract with respect to the tension acting around the seal hole. Therefore, it is possible to prevent the occurrence of cracks by absorbing the tearing force generated around the folded portion. Further, as described above, when the expanding and contracting portion is meandered, the meandering portion always has a portion intersecting the tension acting in the longitudinal direction of the bead with the tension acting direction. Therefore, it is possible to prevent cracking regardless of the direction in which the tension acts.

The metal gasket of the present invention normally uses a laminated gasket, but it may be a single-plate gasket. Further, as in the case of the conventional metal gasket, a sealing material may be applied to the gasket surface in order to seal fine scratches on the joint surface, so-called tool marks.

[0008]

EXAMPLES The present invention will be described in detail by way of examples with reference to the accompanying drawings. A metal gasket 1 according to a first embodiment shown in FIGS. 1 and 2 has a surface plate 2 made of a thin metal plate and a hole to be sealed (hereinafter referred to as a seal hole) such as a cylinder hole of an internal combustion engine (not shown). The folded-back portion 6 was formed by folding back at the peripheral edge of No. 4, and the elastic portion 10 was formed around the seal hole 4 outside the outer peripheral edge 8 of the folded-back portion 6. As shown in FIG. 1, the expansion / contraction part 10 has an arc-shaped cross section in the width direction, and the convex side of the expansion / contraction part 10 protrudes toward the folding part 6 side, that is, the inside of the metal gasket 1, and is shown in FIG. Thus, it was formed in a meandering shape in the circumferential direction. Note that FIG. 2 exaggerates the meandering. Then, a thickness adjusting plate 12 made of a thin metal plate for thickness adjustment and the other surface plate 14 were laminated on the projecting side of the elastic portion 10.

The surface plate 14 is provided with an opening 16 surrounding the sealing hole 4 so that the surface plate 14 overlaps with the folded-back portion 6, and a bead 20 is formed near the periphery of the opening 16 so as to overlap with the folded-back portion 6. I chose As the thickness adjusting plate 12, a plate slightly thinner than the surface plate 2 is used so that the compressive force is concentrated on the bead 20, and an opening 18 surrounding the sealing hole 4 is provided so as not to interfere with the expansion / contraction part 10. A gap Δ is formed between the 16 and the opening 18. The planar shape of the opening 18 was formed in a meandering manner as shown in FIG.

The operation when the metal gasket 1 is mounted between the gasket and a joint surface (not shown) having a different coefficient of thermal expansion will be described with reference to FIG. For example, internal combustion engines for heavy vehicles may have thermal expansion lengths of up to 100 microns in the longitudinal direction when the engine is running and stopped. Therefore, the slip length of the joint surface becomes considerably large due to the difference in the coefficient of thermal expansion from that of a gasket using a highly elastic metal such as spring steel. Since the total plate thickness of the part provided with the expansion / contraction part 10 is small, the compressive force acting is small, so that the part can be expanded / contracted. Therefore, since the sliding length becomes large, when the tearing force along the folded-back portion 6 acts, the expansion / contraction portion 10 expands, absorbs the tearing force, and cracks can be prevented from occurring.

Next, in a state in which the metal gasket 1 is compressed, the tension T indicated by an outline arrow is applied to the portion 22 (FIG. 2) of the expansion / contraction portion 10 due to the large difference in the coefficient of thermal expansion. Explain when it works. Since the surface plate 2 on the side where the thickness adjusting plate 12 is arranged, that is, the side where the total plate thickness is slightly thinned can be deformed, the tension T is concentrated in the vicinity of the folded portion 6. However, in the stretchable portion 10 of the first embodiment, there is always a portion in the width direction within the direction in which the tension T acts, and the portion elastically deforms and expands, and the tearing force can be absorbed. Therefore, when the tension T exceeds the strength of the surface plate 2 due to a decrease in the strength of the spring steel due to long-term use, a crack is generated in the surface plate 2 at the two-dot chain line portion. It can be prevented from occurring.

In the metal gasket 1 of the second embodiment shown in FIG. 3, a gap Δ is formed between the opening 8 and the opening 18 so that the expansion / contraction part 10 contacts the joint surfaces (not shown) on both sides. A ring-shaped thin thickness adjusting plate 24 surrounding the seal hole 4 is interposed in the folded-back portion 6 so that the compressive force is concentrated in the portion. In this case, the thickness adjusting plate 12 forming one surface plate is integrated with the surface plate 2 on which the folded-back portion 6 and the expansion / contraction portion 10 are formed by means such as caulking (not shown). In this way, even when the elastic part 10 is brought into contact with the joint surfaces on both sides, a high tightening force does not act on the elastic part 10. Therefore, similarly to the first embodiment, with respect to the tearing force in any direction, the elastic portion 10 arranged in the width direction is present near the point of action, and the tearing force can be absorbed. In the present proposal, the expansion / contraction part 10 can be provided in parallel with the seal hole 4 without being meandered as described above. Further, when the site where the tension T in FIG. 2 acts is clear, only the vicinity of the site needs to meander.

[0013]

[Effect of the device]

 As described above, according to the present invention, in the metal gasket in which the folded portion is formed around the seal hole and the folded portion that covers the sealing means such as the bead is provided, the expandable portion is provided in the vicinity of the seal means. Therefore, even if the strength deteriorates to less than the tearing force due to heat deterioration or the like, the generation of cracks can be prevented. Therefore, the reliability of the metal gasket can be improved and the metal gasket can be stably used for a long period of time.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a metal gasket according to a first embodiment of the present invention.

FIG. 2 is a partial plan view of a main part of FIG.

FIG. 3 is a sectional view of an essential part of a metal gasket according to a second embodiment of the present invention.

[Explanation of symbols]

 1 Metal Gasket 2 Metallic Thin Plate 4 Sealing Hole 6 Folding Part 8 Outer Edge 10 Expansion / Contraction Part 12 Thickness Adjustment Plate 14 Metallic Thin Plate 20 Bead T Tear Force

Claims (2)

[Scope of utility model registration request] 1. One of the surface plates made of laminated metal thin plates is folded back at the periphery of a seal hole to form a folded part surrounding the seal hole, and a thickness adjusting plate made of a thin metal plate is laminated on the surface plate. The thickness adjusting plate is provided with an opening surrounding a hole to be sealed, the opening is provided with a ring-shaped clearance between the opening and the outer peripheral edge of the folded portion, and the surface plate in the clearance has a hole to be sealed. A metal gasket having a stretchable portion formed by a stretchable portion composed of surrounding grooves. 2. The metal gasket having a stretchable portion according to claim 1, wherein the stretchable portion is formed in a meandering groove shape.