JPH09177976A - Metal hollow o-ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of a breakage and the like effectively, even though an 0-ring is used at a fluid passage which raises the pressure suddenly, by providing a molybdenum desulfide or a graphite fluoride as a covering member, on the peripheral surface of the metal O-ring abutting with two members to be sealed. SOLUTION: At an installing member 12 composed of a metal such as a stainless steel, a circular installing groove 13 is formed. The metal O-ring 16 of a metal hollow O-ring 10 consists of an elastic metal such as a stainless steel, and on the peripheral surface of its inner periphery side, plural small holes 17 as the balance holes are formed at a specific interval. And on the outer surface of the metal O-ring 16, a covering layer 18 of molybdenum desulfide or graphite fluoride as a solid lubricant is provided. As a result, even though it is used to a fluid passage which is made in a high pressure suddenly, the friction resistance at the abutting surface of the metal hollow ring 10 is small, and since a dislocation is generated there, the tensile stress is never increased partially, so as to prevent a breakage.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a metal hollow O-ring used as a gasket for sealing a high-pressure fluid.

[0002]

2. Description of the Related Art Generally, a metal hollow O-ring 1 as shown in FIG. 4 has been conventionally used as a gasket for sealing high pressure fluid. This metal hollow O-ring 1 is
It is a metal O-ring with a hollow inside, and a plurality of small holes 2 called balance holes are formed on the peripheral surface in contact with the fluid. In addition, the surface of the metal hollow O-ring may be coated with a soft metal such as copper or silver, a fluororesin, or a polyimide resin having a strain amount larger than that of a metal with respect to a load for the purpose of enhancing airtightness.

Such a metal hollow O-ring 1 is used in a state in which it is compressed to the height D of the seal groove 3 and is closed. At that time, the high-pressure fluid flowing inside penetrates into the metal hollow O-ring 1 through the small holes 2, so that the inside becomes a high pressure, and the inside surface of the sealing surface S and the groove 3 is surrounded by O. The ring 1 will be pressed.

As described above, since the metal hollow O-ring 1 has its own self-adhesive action, it is not damaged by a high-pressure fluid and exhibits a high sealing property.

[0005]

By the way, the metal hollow O
When the ring 1 is mounted in the groove 3, there is a space that does not contact the O-ring 1 at the corner portion of the groove 3.

Here, if the pressure in the fluid passage R formed between the two members 4 and 5 is relatively low, or if the pressure in the fluid passage R is high but the pressure rising rate is small, The pressure in the fluid passage R causes the metal hollow O-ring 1 to slowly deform into the space of the corner portion as shown by the chain double-dashed line, so that the metal O-ring 1 does not break.
However, when the final pressure is high (for example, 100 MPa or more) and the pressure increase rate is high (for example, 10 MPa).
(0 MPa / sec or more), there was a problem that the metal hollow O-ring 1 was broken by tensile stress.

When the metal O-ring is completely closed in the groove, the sliding contact portion of the metal hollow O-ring 1 is extremely difficult on the contact surface G between the metal O-ring 1 and the wall surface of the groove 3 or the seal surfaces S and S '. It comes into contact with the mating member with a large frictional force.
As a result, a portion H that is not in contact with any of the metal hollow O-rings 1, that is, a portion H that faces the corner portion of the groove 3
When the final pressure is high and the pressure rising speed is high, the contact surfaces S, S ', and G are fixed points, and a sudden expansion force due to the internal pressure is applied to generate a large tensile stress. As a result, there is a problem that breakage occurs in the H portion of the O-ring 1. This is also the case when the metal hollow O-ring is coated with a soft metal, and because of the softness of the soft metal, adhesion on the seal surface is likely to occur and the frictional force on the contact surface increases, resulting in a metal hollow O-ring. Was fractured.

On the other hand, when the outer surface is coated with a resin, the resin coating has a low frictional force against a high pressure fluid accompanied by a rapid pressure rise, so S, S ', and G are fixed points. Does not work and the O-ring as a whole expands due to the expansion force, so breakage does not occur at the H part, but because the expansion occurs at S, S ', G, the resin film peels off due to insufficient strength of the film itself, There was a problem that it was cut and the seal was defective.

In view of the above situation, the present invention provides a metal hollow O-ring which can effectively prevent damage or the like even when it is used in a fluid passage whose pressure rises rapidly. The purpose is to do.

[0010]

A metal hollow O-ring according to the present invention for achieving the above object is disposed in a mounting groove between two members to be sealed, and has a peripheral surface portion in contact with a fluid flow. In a metal hollow O-ring having an opening for introducing a pressure fluid, at least the molybdenum disulfide or graphite fluoride is provided as a covering material on at least the peripheral surface of the metal O-ring that contacts the two members to be sealed. It is characterized by that.

[0011]

According to the present invention having the above-mentioned structure, since the slippery coating layer is applied to the outer peripheral surface of the metal O-ring with a predetermined thickness, even when the metal O-ring is used in a fluid passage which suddenly becomes a high pressure. Since the frictional resistance at the contact surface of the metal hollow O-ring is small and there is a deviation here, the tensile stress at the portion of the groove of the metal O-ring facing the corner portion does not become large, and therefore, No damage will occur.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a state in which a metal hollow O-ring 10 according to the present invention is applied to semiconductor equipment or the like.

In the figure, 11 and 12 are hollow mounting members made of metal such as stainless steel.
An annular mounting groove 13 is formed. This mounting member 1
The bolts 1 and 12 are fastened and fixed by bolts (not shown) attached to the flanges 14 and 15.

Metal O-ring 16 of hollow metal O-ring 10
Is made of an elastic metal, and specific examples thereof include stainless steel. A plurality of small holes 17 called balance holes are formed at predetermined intervals on the inner peripheral surface of the metal O-ring 16.

Then, on the outer surface of the metal O-ring 16,
A coating layer 18 made of a solid lubricant is provided. Examples of the solid lubricant include graphite, fluorinated graphite, molybdenum disulfide, tungsten disulfide, boron nitride, tantalum disulfide, calcium fluoride and the like. Among these, it is preferable to use fluorinated graphite or molybdenum disulfide, which has excellent heat resistance and has an appropriate hardness and an appropriate friction coefficient.

Molybdenum disulfide has a Mohs hardness of 1
The range is up to 1.5 and the coefficient of friction is 0.05. According to the experiment, it was confirmed that when the Mohs hardness is 1 or more and 4 or less, the conformability to the mating member is good and the good sealing property is exhibited. Further, the coefficient of friction is 0.
It was also confirmed that if it is 01 or more and 0.1 or less, the contact portion is apt to be displaced and the tensile stress does not act largely in the H portion.

Further, the thickness of the coating layer 18 is 1 ×
10 ⁻⁸ to 1 × 10 ⁻⁴ m, preferably 1 × 10 ^{−6 to} 5 × 10
^-5 m thickness is preferred. That is, if the thickness is smaller than the above range, good conformability to the mating member cannot be obtained, and conversely, if the thickness is thick, peeling of the coating material occurs, resulting in poor sealing.

With such a coefficient of friction and Mohs hardness,
Further, it was confirmed that when the thickness is within the above range, the frictional force with the mating member at the contact portion is small, the conformability to the mating member is good, and a predetermined sealing property is exhibited.

Although the opening 17 is a small hole in the above-mentioned embodiment, the opening 20 may be replaced by an opening 20 which is not discontinuous in the circumferential direction, as shown in FIG. The present invention can also be applied to a metal O-ring 16 in which a coil spring is interposed on the inner circumference.

Further, in the above embodiment, the metal O-ring 1
Although the example in which the coating layer 18 is provided over the entire circumference of 6 has been shown, the coating layer 21 may be provided only on the outer peripheral side as shown in FIG. Alternatively, as shown in FIG. 3, the coating layer 22 may be provided only on the portion where the metal O-ring 16 contacts the surroundings.

Even in such an embodiment, the same operational effect as that of the above-mentioned embodiment is obtained, and breakage or the like does not occur.

[0022]

As described above, according to the metal hollow O-ring according to the present invention, since the outer peripheral surface of the metal O-ring is coated with the coating layer having the predetermined hardness which is slippery and has the predetermined hardness, Even when it is used in a high-pressure fluid passage, the frictional resistance at the contact surface of the metal hollow O-ring is small and the contact surface is displaced, so that the tensile stress is not partially increased. Absent. Therefore, damage or the like can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a mounted state of a metal hollow O-ring according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a mounted state of a metal hollow O-ring according to another embodiment of the present invention.

FIG. 3 is a sectional view showing a mounted state of a metal hollow O-ring according to still another embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a mounted state of a conventional metal hollow O-ring.

[Explanation of symbols]

 10 Metal Hollow O-ring 11, 12 Mounting Member 13 Groove 16 Metal O-ring 18 Coating Layer

Claims (3)

[Claims] 1. A metal hollow O-ring, which is disposed in a mounting groove between two members to be sealed and has an opening for introducing a pressure fluid in a peripheral surface portion in contact with a fluid flow, wherein at least the sealing ring is provided. A hollow metal O-ring which is provided with either fluorinated graphite or molybdenum disulfide as a coating layer on the peripheral surface of the metal O-ring which is in contact with the two members. 2. The coating layer is 1 × 10.^-8~ 1 × 10^-Fourm
Preferably 1 × 10 ^-6~ 5 × 10^-Fivem thickness
The metal hollow O-ring according to claim 1. 3. The hollow metal O-ring according to claim 1, wherein the coating layer has a friction coefficient of 0.1 or less and a Mohs hardness of 1 to 4.