JP2811186B2 - Compression transformation type metal seal member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention exerts a sealing effect particularly when inserted into an O-ring groove formed in a sealing surface of a high-pressure pipe or a high-pressure container or sandwiched between flanges. The present invention relates to a metal sealing member.

(Prior Art) A metal gasket and a metal O-ring having a central core formed by forming a metal wire coil spring into an annular body in a continuous winding state and a metal outer skin surrounding the outer periphery thereof are already widely known. It is described in JP-B-51-46220 "Elastic metal gasket".

The relationship between strain and pressure in such a metal gasket is as shown in FIG. 6 of the accompanying drawings. When the strain exceeds a certain limit point B, the coil spring buckles and its circular cross section breaks, losing the sealing effect. . The broken circular cross section does not return to its original shape even when the load is removed. Therefore, the usable range is from the seal point S to which the initial strain is applied to the point K at which buckling deformation starts, and in practice, a considerably lower range is used for safety. For this reason, there is a disadvantage that the amount of strain is limited and the applicable range to be sealed is narrowed.

In Japanese Patent Publication No. 57-41628 "elastic metal gasket", a reinforcing strip is disposed inside or outside a coil spring to prevent the gasket from being deformed beyond a certain limit when the gasket is tightened. Therefore, the amount of strain is suppressed below the thickness of the reinforcing strip, and the applicable range of the gasket is naturally limited.

Japanese Patent Application Laid-Open No. 60-227091 also discloses that a rocking ring is inserted into an elliptical coil spring to limit the collapse of the joint.

(Problems to be Solved by the Invention) An object of the present invention is to provide a metal seal member having a central core and a metal sheath, while securing a wide use range,
The purpose is to increase the reliability of the seal.

(Means for Solving the Problems and Action Thereof) The above-mentioned object of the present invention is to provide a metal core made of a metal coil spring having a hollow, elliptical cross section and being annular and elastic, At least one metal shell surrounding the outer periphery, wherein the oval is an oval whose length in a direction perpendicular to the central axis is larger than a length in a direction parallel to the central axis, When the metal shell is compressed in a direction parallel to the central axis, the metal shell first contracts while maintaining a substantially elliptical cross section, and seals with a single circle whose upper and lower compressed surfaces are respectively continuous in the circumferential direction, When subjected to a compressive force above a certain transformation point, the upper and lower compressed surfaces are deformed to exhibit arch surfaces bent from the vicinity of the center thereof, and are sealed by two concentric circles continuous in the circumferential direction. Metal seal member Achieved by

Based on such a configuration, according to the metal seal member of the present invention, the characteristic curve is as shown in FIG. From the seal point S to which the initial strain is applied to the transformation point H, a seal is made with one wide circle continuous in the circumferential direction as in the past,
When it comes to the transformation point H, the vicinity of the center of the metal outer skin is bent in an arch shape, and the contact points become two places, and the two outer circumferential concentric circles are sealed. When the metal core further distorts and reaches the internal contact point C, the upper and lower portions of the metal core come into contact with each other (see FIG. 3), and when the distortion further reaches the point K, buckling deformation starts. When the buckling point B is reached, the metal core and the metal skin are broken and lose their sealing effect. Therefore, in the seal member according to the present invention, the usable range is from the seal point S to the buckling deformation start point K, and the use range is much wider than before and the applicable range is expanded. In addition, two concentric seals provide a double seal, with the benefit of improved reliability.

When it is desired to prevent the upper and lower portions of the metal core from coming into contact with each other, an annular disk for preventing deformation can be inserted into the metal core to limit the amount of strain.

In addition, the reliability of the sealability, durability, and the like can be further improved by forming the metal outer skin surrounding the outer periphery of the metal core into a two-piece structure.

Other features and advantages of the present invention will become apparent from the following description in which reference is made to the embodiments of the accompanying drawings.

(Embodiment) FIG. 1 shows a state of a metal seal member 10 according to the present invention at no load in a cross-sectional shape.
Is a metal core 12 made of a metal coil spring having a hollow, elliptical cross section and an annular elasticity, and one metal core surrounding the outer periphery of the metal core and radially outwardly continuous in the circumferential direction. A metal shell 14 having a cut 16. The cut 16 may be located radially inward depending on the application of the seal. In addition, the metal shell 14 can be formed in a two-layer structure. The coil spring constituting the metal core 12 is wound so as to be continuously in close contact with each other to form an annular body, and the “oval cross section” refers to a cross-sectional shape perpendicular to the center line of the wound spring. Note that it looks like an oval.

This oval is an oval in which the length W in the direction perpendicular to the central axis 20 of the seal member is larger than the length T in the direction parallel to the central axis.

FIG. 2 shows a first-stage deformed state in which the sealing member 10 is sandwiched between the flanges and compressed in a direction parallel to the central axis, and the metal core 12 and the metal sheath 14 are It is compressed in a parallel direction and contracts while maintaining a substantially elliptical cross section, and the upper and lower compressed surfaces are each sealed by one wide circle 18 that is continuous in the circumferential direction.

FIG. 3 shows a second-stage deformed state in which the seal member 10 is further compressed and receives a compressive force equal to or higher than a transformation point, and the upper and lower compressed surfaces are arch surfaces bent from near the center thereof. The upper and lower surfaces are sealed by two concentric circles 35 and 36 that are circumferentially continuous. Thus, a double sealing line is provided and a reliable sealing effect is obtained. In the state shown in FIG. 3, the upper and lower arch surfaces are in contact inside, and this state corresponds to point C in FIG. 7, and furthermore, it can withstand a compressive force until point K at which buckling deformation starts. The scope of application is quite broad.

FIG. 4 shows an embodiment in which the oval shape of the metal core and the metal skin is further flattened, and both ends 41, 42 in the radial direction are shown.
In order to prevent buckling failure from easily occurring, an annular flat plate 45 extending in a plane perpendicular to the central axis is inserted inside. The ends of the flat plate 45 may be welded and connected before the ends of the coil springs constituting the metal core are connected, or may be left overlapped. In this example,
When a compressive force of a certain transformation point or more is received, a deformed state as shown in FIG. 5 is obtained, and the upper and lower compressed surfaces are arched surfaces 51 and 52 bent from the vicinity of the center as in FIG. However, since the flat plate 45 is provided, the amount of strain is limited to some extent, and buckling deformation at both ends 41 and 42 is prevented. Even in the state of FIG. 5, the upper and lower surfaces are sealed by two concentric circles 55 and 56 that are continuous in the circumferential direction, and a highly reliable sealing effect based on the double sealing line is obtained.

(Effects of the Invention) As described in detail above, according to the metal seal member of the present invention, a wide range of use can be ensured in a seal for a high-pressure pipe or a high-pressure container having a central core and a metal sheath, and a seal is provided. The technical effect is extremely remarkable, for example, the reliability of the device is improved, and the safety of the device and the whole system is improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a metal seal member according to a preferred embodiment of the present invention cut along a plane including a central axis, and FIG. 2 shows a state where the seal member is subjected to first-stage compression deformation between flanges. FIG. 3 is a cross-sectional view showing a state where the seal member is undergoing a second-stage compression deformation between the flanges, and FIG. 4 is a first-stage compressed state of the seal member according to another embodiment. FIG. 5 is a cross-sectional view showing a second stage compression state, FIG. 6 is a graph showing a relationship between pressure and strain of a conventional metal gasket, and FIG. 7 is a pressure of a seal member according to the present invention. 6 is a graph showing a relationship between the stress and the strain. 10 Seal member, 12 Metal core 14 Metal shell, 16 Cut 18 Circle, 20 Center axis 31, 32 Arch surface 35, 36 Concentric circle, 45 Flat plate

Claims (2)

(57) [Claims] 1. A metal core comprising a metal coil spring having a hollow, elliptical cross section and being annular and elastic, and at least one metal outer shell surrounding an outer periphery of the metal core, The circle is an ellipse in which the length in the direction perpendicular to the central axis is larger than the length in the direction parallel to the central axis.When the metal core and the metal outer cover are compressed in a direction parallel to the central axis, At first, the upper and lower compressed surfaces are contracted while maintaining the almost oval cross section, and the upper and lower compressed surfaces are sealed with one circle continuous in the circumferential direction. A compression-transformed metal seal member characterized by being deformed so as to exhibit an arch surface bent from the vicinity of the center thereof and sealing with two concentric circles continuous in a circumferential direction. 2. An annular disk extending in a plane perpendicular to the center line is disposed inside the metal core.
The metal seal member as described in the above.