JPH0420996Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a manifold gasket or a cylinder head gasket for keeping combustion gas confidential at high temperatures and pressures in automobile diesel engines.

2. Description of the Related Art A metal gasket shown in FIG. 3 is known as a gasket used in a manifold or cylinder head of a high-load engine. This gasket has an upper sheet a and a lower sheet b made of metal gasket sheets, and beads c are formed on the hole edge sides of the sheets facing the fluid passage.
A seal ring d made of a steel wire such as stainless steel is loaded into the gap formed by the seal ring d, and the tip of the bottom sheet b is bent into an inverted U-shape. Furthermore, the gasket shown in FIG. 4 has an upper surface metal sheet a having beads c similar to the gasket shown in FIG. The tip of the sheet b is formed into a c-shape.

Problems to be solved by the invention The conventional metal gasket shown in Fig. 3 above has the following problems:
Since surface pressure is applied only to the seal ring part, dents are easily formed on the flange part f, and the flange part is easily deformed, and the load rises sharply in the load-displacement characteristics, resulting in slight variations in the thickness of the seal part. However, the change in seal load is large and causes fluid leakage. Furthermore, the metal gasket shown in Fig. 4 has a gap between the upper and lower beads when assembled, so it is struck by the behavior of the flanges, etc., and in the long run, the gap disappears and it becomes difficult to maintain surface pressure, causing the fluid to flow. This is causing a leak. In addition, in order to prevent dents from forming on the flange part f, if the seal ring included in the grommet is made of mild steel wire, it is possible to prevent the flange part from forming dents, but on the other hand, there is a drawback that the seal ring easily wears out. .

Therefore, a cylinder head casket can be considered that has a structure in which large and small seal rings are covered with grommets (outer plate), or a structure in which a metal sheet with large and small beads is covered with grommets, but these are placed between the flanges of the cylinder head. When installed, the grommet contacts the cylinder head, cylinder liner, and crankcase, so in the former case, there is a problem in that surface pressure is applied only to the seal ring portion.

In addition, in the latter case, there is no significant difference in compression characteristics between the large and small protrusions, and there is a problem in that when the gasket sheet becomes flat in the end, sufficient repulsive force cannot be obtained.

Means for Solving the Problems In order to solve the above-mentioned problems, this invention involves polymerizing inner metal sheets with beads provided on the upper and lower surfaces of a central metal plate to form a laminated metal gasket sheet, and forming a laminated metal gasket sheet. A seal ring made of a solid round mild steel wire is disposed at the edge of the hole facing the fluid passage of the gasket sheet, and an inner peripheral bead for enclosing the seal ring and an outer peripheral bead that fits into the bead of the inner metal sheet are arranged. An outer metal sheet having a structure is superposed on the upper surface of the inner metal sheet, and the height h ₁ of the outer peripheral bead portion superposed on the bead of the inner metal sheet is higher than the height h 2 of the inner peripheral bead portion including the seal _ring . It consists of a large metal gasket.

Function When the metal gasket of this invention is sandwiched between sealing flanges and tightened with bolts, the flange first hits the outer peripheral bead to prevent fluid leakage, and then the flange hits the inner peripheral bead. In this way, the surface pressure is divided into two stages by the outer bead and the inner bead,
Settling due to the behavior of the outer bead is compensated for by the rigidity of the inner bead, and the sharpness of the rise of the load on the inner bead is maintained and blunted by the outer bead, thereby obtaining the amount of compression and reducing load fluctuations. This increases the sealing effect, and since the tightening force is not concentrated on the inner bead, no impression is left on the flange.

Embodiment An embodiment of this invention will be explained using an exhaust manifold gasket. In FIGS. 1 and 2, 1 is an exhaust manifold gasket. Reference numeral 2 denotes a central metal plate, and a metal gasket sheet 10 is formed by laminating inner metal sheets 3 on the upper and lower surfaces of the central metal plate 2, respectively. The inner metal sheet 3 laminated on the center metal plate 2 is
Beads 3a that protrude outward are formed inwardly from the hole edge 2b facing the fluid passage 6, and the beads 3a with respect to the central metal plate 2 close the gap 2a.
is formed. A seal ring 4 made of a solid round mild steel wire is disposed on the hole edge 2b facing the fluid passage 6 in the center metal plate 2, and the outer metal sheet 5 for enclosing the seal ring 4 has a curved surface of the seal ring 4. It has an inner peripheral bead 5a that matches the inner peripheral bead 5a and an outer peripheral bead 5b that overlaps with the bead 3a of the inner metal sheet 3.

This outer metal sheet 5 is polymerized and laminated on the upper surface of the inner metal sheet 3 to form an exhaust manifold gasket. Further, the height h ₁ of the bead overlapping portion 5b of the inner surface metal sheet 3 and the outer surface metal sheet 5 is made larger than the height h ₂ of the inner peripheral bead overlapping portion 5a of the outer surface metal sheet 5, and height h ₂
is formed so that the height is greater than the height _h3 of the overlapping portion of the central metal plate 2 and the inner metal sheet 3. In the figure, 7 is a bolt mounting hole, and 8 and 9 are sealing flanges.

Effects of the invention This invention has beads 3a on the upper and lower surfaces of the central metal plate 2.
The inner metal sheet 3 provided with the cylinder head gasket is polymerized, and the outer metal sheet 5 including the seal ring 4 made of a round round wire of mild steel is laminated on the inner metal sheet 3. There is no need to cover it with an outer panel).

Further, the outer metal sheet 5 has a bead 5b that matches the bead 3a of the inner metal sheet 3, and the height h ₁ of the outer bead b is equal to the height h ₂ of the bead 5a at the inclusion part of the seal ring 4 made of a solid round mild steel wire. When installed on a cylinder head, etc., the outer metal sheet comes into direct contact with the manifold of a high-load engine or the flange of the cylinder head.

Therefore, when a metal gasket is sandwiched between flanges 8 and 9 and tightened with bolts, flanges 8 and
9 first hits the outer peripheral bead 5a to prevent fluid leakage, and then when the flanges 8 and 9 hit the inner peripheral bead 5a containing the seal ring 4 formed of a solid round mild steel wire, the repulsive force of the outer peripheral bead 5b is applied. teeth,
Since the stiffness of the inner peripheral bead compensates for the settling caused by the behavior of the flange, it can be held for a long time and prevent fluid leakage. At this time, the load on the inner peripheral bead 5a is
Since the load is distributed to the outer bead, it is not concentrated. As a result, even if the thickness of the entire gasket in its assembled state varies greatly, the variation in load can be reduced. Furthermore, since the tightening force can be dispersed, there is no impression on the flange. Furthermore, the elasticity of the inner peripheral bead 5a and the outer peripheral bead 5b can prevent deformation of the mating flange surface, making it possible to completely prevent liquid leakage due to flange deformation.

In this invention, as described above, the surface pressure is shared in two stages between the outer peripheral bead 5b and the inner peripheral bead 5a of the outer metal sheet containing the seal ring 4, so that the sealing effect can be increased. In addition, it is possible to prevent impressions on the flange portion, and furthermore, the seal ring made of a solid round mild steel wire can prevent fluid leakage between layers.

Further, due to the gas barrier effect of the inner peripheral bead portion including the seal ring, thermal fatigue can be reduced with respect to the outer peripheral bead portion.

This idea allows the spring characteristics of the inner metal sheet bead to be finely adjusted by polymerizing the outer metal sheet and the inner metal sheet, especially in the bead part, and by providing a bead part on the outer metal sheet as well. Furthermore, by changing the thickness of the inner and outer metal sheets, it is possible to set the characteristics over a wide range.

The load (Kg/cm) with respect to the displacement of the invented gasket A, the gasket B shown in Fig. 3 that uses only a conventional seal ring, and the gasket C shown in Fig. 4 that uses only a bead instead of a seal ring is as follows. As shown in FIG. That is, the gasket of the present invention can increase the load per unit length for an appropriate amount of displacement.

For example, for a displacement of 0.4 mm, the load required for a seal of about 500 kg/cm can be easily obtained.

[Brief explanation of the drawing]

The figures show one embodiment of this invention; Fig. 1 is a front view of the gasket; Fig. 2 is a sectional view taken along the line - - in Fig. 1; Figs. 3 and 4 are sectional side views of a conventional gasket; FIG. 5 is a diagram showing the displacement/load of the gasket of the present invention and the conventional gasket. 1...Exhaust manifold gasket, 2
... Central metal plate, 3, 3 ... Inner metal sheet, 3
a... Bead, 4... Seal ring, 5... External metal sheet, 5a... Inner peripheral bead, 5b... Outer peripheral bead, 10... Laminated metal gasket sheet.

Claims (1)

[Scope of utility model registration request] A laminated metal gasket sheet is formed by polymerizing inner metal sheets with beads provided on the upper and lower surfaces of the central metal plate, and a seal ring made of a round mild steel wire is filled at the edge of the hole facing the fluid passage of the laminated metal gasket sheet. an outer metal sheet having an inner peripheral bead for enclosing the seal ring and an outer peripheral bead that fits into the bead of the inner metal sheet is superimposed on the upper surface of the inner metal sheet, and a seal ring is disposed on the upper surface of the inner metal sheet. A metal gasket characterized in that the height h ₁ of an outer peripheral bead portion superposed on the bead of the inner surface metal sheet is greater than the height h ₂ of the inner peripheral bead portion.