JPH022120Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention forms an inner bead surrounding the cylinder hole, an outer bead on the outer periphery of the elastic metal plate, and a hole bead surrounding the hole around the cylinder hole. The present invention relates to an improvement in a metal gasket that is integrally formed with a metal gasket, and particularly to a metal gasket that can achieve effective sealing by forming beads depending on the sealing area.

[Prior Art] In a metal gasket that forms a bead on an elastic metal plate to achieve a seal, the bead is elastically deformed by an appropriate pressing force, and the end of the bead is pressed against a joint surface by elastic restoring force to achieve a seal. There is.

Among such metal gaskets, a metal gasket that achieves cooling by flowing cooling water between the joint surfaces of the cylinder head and cylinder block of an internal combustion engine is constructed as shown in FIG. 4. That is,
The metal gasket 2 made of an elastic metal plate has an inner bead 6 surrounding the cylinder hole 4, an outer bead 8 on the outer periphery of the metal gasket, and a hole 12 for inserting a fastening bolt 10 arranged around the cylinder hole. The surrounding hole bead 14 is joined by a bead joint 16 and formed integrally. Cooling water holes 18 through which cooling water is pumped between the inner bead 6 and the outer bead 8 and the hole bead 14
Cooling water is passed through a cooling water channel (not shown) formed by the inner bead 6, the outer bead 8, the hole bead 14, and the joint surface, thereby achieving cooling.

[Problems to be Solved by the Invention] However, the effect of the fastening force is weakened at a location between the holes 12 that is farther away from the hole 12 than the periphery of the hole 12, which is the bolt fastening region. In addition, since the bead has a single cross-sectional shape, the hole bead 14 can obtain sufficient sealing pressure, but the sealing pressure is weakened at the outer bead intermediate portion 20 between the hole beads 14, causing leakage of the pumped cooling water. There was a drawback that it was easy to cause.
In order to eliminate this drawback, we partially laminated the boards,
Or the fastening force was strengthened. However, partial lamination of plates causes distortion in the joined members when fastened, and when the fastening force is strengthened, the sealing pressure around the hole 12 increases more than necessary, causing bead breakage and joint surfaces to be damaged, causing cooling water to leak into the hole. This caused the inconvenience of leakage to the portion 12.

Furthermore, even in the hole 12 which is the fastening part,
In a gasket configured to allow oil to flow through the hole 12, if a strong fastening force is applied to prevent leakage of the coolant being pumped into the hole 12, the hole bead located on the inner bead side from the bead joint 16 will be sealed. The inner part 22 can obtain the necessary sealing pressure and prevent leakage, but the sealing pressure in the hole bead outer part 24 located on the outer peripheral edge side from the bead joint 16 increases too much, causing problems such as bead breakage and damage to the joint surface. occurred. Furthermore, when sealing is performed with a weak fastening force to prevent oil leakage, the outer part 24 of the hole bead can prevent oil leakage, but the inner part 22 of the hole bead cannot seal the pumped cooling water, and the cooling water is mixed with the oil. This caused the inconvenience of contamination.

As such, the hole bead inner portion 22 requires greater sealing pressure than the hole bead outer portion 24;
Further, the outer bead intermediate portion 20 requires a larger sealing pressure than the hole bead inner portion 22, and the required sealing pressure differs depending on the sealing portion. For this reason, the conventional bead with a single cross-sectional shape could not satisfy the required sealing pressure of each sealing part, and could not achieve effective sealing.

[Purpose of the invention] Therefore, this invention solves these problems and
In a metal gasket integrally formed by forming an inner bead surrounding a combustion chamber hole, and joining an outer bead on the outer periphery of the elastic metal plate and a hole bead surrounding the hole around the cylinder hole at a bead joint, The object of the present invention is to realize a metal gasket that can achieve effective sealing by forming beads in accordance with each sealing area.

[Means for Solving the Problem] In order to achieve this object, this invention forms an inner bead surrounding the cylinder hole in the elastic metal plate, and an outer bead on the outer periphery of the elastic metal plate and the outer bead surrounding the cylinder hole. In a metal gasket integrally formed by joining a hole bead surrounding a hole disposed in a hole at a bead joint, the spring constant of the intermediate portion of the outer bead located between the hole beads is A,
The spring constant of the inner part of the hole bead located on the inner bead side from the bead joint part is B, the spring constant of the outer part of the hole bead located on the outer peripheral edge side of the elastic metal plate from the bead joint part is C, and A
The present invention is characterized in that the beads are formed to satisfy the relationship >B>C.

[Example] Next, an example of this invention will be described in detail based on the drawings. 1 to 3 show examples of this invention. In the figure, parts that perform the same functions as those in FIG. 4 are given the same reference numerals and explained. That is,
An inner bead 6 is formed surrounding the cylinder hole 4 of the metal gasket 2 made of an elastic metal plate, and a hole surrounding the outer bead 8 on the outer periphery of the metal gasket and the hole 12 for inserting the fastening bolt 10 around the cylinder hole. The bead 14 is joined to the bead joint part 16 and formed integrally. This inner bead 6 and outer bead 8
Cooling water holes 18 are formed between the two, and cooling water is circulated to achieve cooling.

In this invention, the outer bead intermediate portion 26 between the hole beads 12, the hole bead inner portion 28 on the inner bead side from the bead joint 16, and the hole bead outer portion 30 on the outer peripheral edge side of the metal gasket from the bead joint 16. Each has a different spring constant. That is, as shown in FIGS. 2 and 3, the cross-sectional shape of each bead is such that the bead height h is constant,
The bead width a of the outer bead intermediate portion 26, the bead width b of the hole bead inner portion 28, and the bead width c of the hole bead outer portion 30 are formed to satisfy the relationship a<b<c. As a result, the spring constant of the outer bead intermediate portion 26 is A, the spring constant of the hole bead inner portion 28 is B, and the spring constant of the hole bead inner portion 30 is set to
The spring constant of is C, and the bead is formed to satisfy the relationship A>B>C.

Of course, these bead shapes are such that the bead width a is set to a value that corresponds to the spring constant A that should obtain a sealing pressure sufficient to prevent cooling water leakage due to weak fastening force, and the bead width b
is the spring constant B that should provide a sealing pressure sufficient to prevent the pumped cooling water from leaking into the hole 12 and mixing with the oil, and the bead width c is a value that is sufficient to prevent oil from leaking to the outside. They are each formed to a value that corresponds to the spring constant C that should provide a sufficiently weak sealing pressure. As a result, the elastic restoring force of the hole bead inner region 28 is stronger than that of the hole bead outer region 30, and the elastic restoring force of the outer bead intermediate region 26 is stronger than that of the hole bead inner region 28.

When the metal gasket 2 having this configuration is interposed between the cylinder head 32 and the cylinder block 34 and tightened with the fastening bolt 10, the fastening force acts weaker between the holes 12 than between the holes 12. but,
Hole bead inner part 28 and hole bead outer part 3
Bead intermediate part 2 outside than spring constant B/C of 0
Since the bead is formed so that the spring constant A of No. 6 is large, the elastic restoring force of the outer bead intermediate portion 26 is strong. Therefore, the outer bead intermediate portion 26 can compensate for the lack of sealing pressure due to the weakening of the fastening force, generate the necessary sealing pressure, and prevent leakage of the pumped cooling water.

Since a sufficient fastening force acts on the periphery of the hole 12, which is the bolt fastening part, the hole bead inner part 28 and the hole bead outer part 30 have spring constants B and C smaller than the spring constant A of the outer bead intermediate part 26. Even with such a bead shape, sufficient sealing pressure can be generated by the elastic restoring force and sealing can be achieved.

Here, when oil is flowing through the hole 12, the hole bead inner side 28 requires sealing pressure sufficient to prevent the pumped cooling water from leaking into the hole 12, but the hole bead outside A weak sealing pressure at site 30 is sufficient to simply prevent oil from escaping to the outside. Therefore, the bead width b is set smaller than the bead width c, and the hole bead inner part 28
Even if the bead is formed so that the spring constant C of the hole bead outer part 30 is smaller than the spring constant B of the hole bead,
It is possible to prevent the oil from leaking to the outside without causing the inconvenience that the pumped cooling water leaks into the hole 12 and mixes with the oil.

In this way, by generating the necessary sealing pressure according to each sealing part, sealing can be achieved effectively without causing problems such as bead breakage or leakage.

Note that the bead is not limited to the illustrated example; the spring constant can be set by keeping the width constant and changing the height, or by a combination thereof, or by changing the wall thickness of the part. is also possible. Furthermore, it is also possible to form beads by work hardening during processing or by setting the spring constant using other hardening means.

[Effect of the invention] As described above, according to this invention, in order to form beads according to the sealing parts of the integrally formed outer bead and the hole bead, the spring constant of the middle part of the outer bead is set to A, and the spring constant of the hole bead is The spring constant of the inner part is B, the spring constant of the outer part of the hole bead is C, and A
The beads are formed to satisfy the relationship >B>C. Therefore, since the elastic restoring force is formed in the relationship of outer bead intermediate region > hole bead inner region > hole bead outer region, different sealing pressures can be generated depending on these elastic restoring forces.

Therefore, by creating different sealing pressures in a metal gasket made of a single elastic metal plate, it is possible to create sealing pressures according to each sealing area without stacking plates or increasing the fastening force, thereby preventing bead breakage. Effective sealing can be achieved without causing leakage or other problems.

[Brief explanation of the drawing]

1 to 3 show an embodiment of this invention, with FIG. 1 being a plan view of a metal gasket, and FIGS. 2 and 3 being an enlarged cross-sectional view taken along the - line and a - line enlarged sectional view of FIG. 1. FIG. 4 is a plan view of a conventional metal gasket. In the figure, 2 is a metal gasket, 4 is a cylinder hole, 6 is an inner bead, 8 is an outer bead, 14 is a hole bead, 16 is a bead joint, 26 is an intermediate portion of the outer bead, 28 is an inner portion of the hole bead, and 30 is a hole bead inner portion. In the outer part of the hole bead, h is the bead height, and a, b, and c are the bead widths.

Claims (1)

[Scope of utility model registration request] An inner bead surrounding the cylinder hole is formed in the elastic metal plate, and an outer bead on the outer periphery of the elastic metal plate and a hole bead surrounding the hole disposed around the cylinder hole are joined together at a bead joint. In the metal gasket formed in the metal gasket, the spring constant of the intermediate portion of the outer bead located between the hole beads is A, the spring constant of the inner portion of the hole bead located on the inner bead side from the bead joint portion is B, and the spring constant of the outer bead intermediate portion located between the hole beads is B; A metal gasket characterized in that the spring constant of the outer portion of the hole bead located on the outer peripheral edge side of the elastic metal plate from the joint portion is C, and the bead is formed to satisfy the relationship A>B>C.