JPH06159515A - Metallic hollow o ring - Google Patents

Abstract

PURPOSE:To restrain deterioration of sealing performance by way of certainly absorbing slippage even when the large slippage is produced between flanges reciprocally due to oscillation and others. CONSTITUTION:In a metallic hollow O ring 1 a part of the surface of a ring coil spring 2 of which ia doubly covered with a metallic inner cover 3 and an outer cover 4 the sectional surfaces of which are C shaped along its overall periphery, a contact part of the inner cover 3 and the outer cover 4 is made to have a sliding function by way of interposing, for example, a lubricating layer 5 made of a partially fixed lubricating agent such as grease and others here.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow metal O-ring used as a gasket for static pressure sealing of pipe joints for ultra-vacuum equipment or nuclear equipment.

[0002]

2. Description of the Related Art A metal hollow O-ring is formed by covering a part of a ring-shaped coil spring with a metal-made covering material having a C-shaped cross section over the entire circumference. A single coating in which is used as a coating material, and a double coating in which two metal plates of an inner cover and an outer cover are superposed are used as a coating material.

The single coating has a relatively simple structure, but in the case where a soft metal plate is used as the coating material and a coil spring is incorporated therein in order to improve the conformability of the sealing surface. The coil spring bites into the inside of the covering material, and the stress between the pitches of the coil spring is reduced.

On the other hand, the double coating was developed in order to make up for the drawbacks of the above-mentioned single coating, and the coating material is formed by using a hard metal plate for the inner cover and a soft metal plate for the outer cover. This prevents the coil spring from penetrating into the covering material (inner cover) to prevent a decrease in stress between the pitches of the coil spring, and at the same time imparts conformability to the sealing surface of the covering material (outer cover). .

Conventionally, in such a metal hollow O-ring having a double coating, the coating material consisting of the inner coating and the outer coating is integrally formed by a metal clad material. It was common to rigidly connect them so that no slippage would occur with the jacket (for example,
1648, JP-A-1-172682, JP-B-56-34741, JP-A-60-8572, JP-B-58-29330).

[0006]

However, in the above-mentioned conventional example, the inner cover and the outer cover are restrained to each other at their rigidly joined joint surfaces, so that the inner cover and the outer cover are freely deformed. There is a certain limit to the amount of deformation of the entire covering material because it is regulated. Therefore, if a considerable amount of deviation occurs between the flanges due to vibration, etc., perform deformation to absorb this deviation amount. However, as a result, the allowable amount of deviation between the flanges has a certain limit, which is not sufficient in reality.

Particularly, when it is used in a place where it is necessary to surely prevent leakage even under a condition where vibration is likely to occur and there is a risk of impact, drop, etc., such as a lid seal of a nuclear fuel transportation container. It was a problem.

In view of the above, the present invention provides a structure in which even if a large deviation occurs between the flanges due to vibration or the like, the deviation is reliably absorbed and the sealing performance is not deteriorated. The purpose is to

[0009]

In order to achieve the above object, the metal hollow O-ring according to the present invention is a metal having a C-shaped cross section over the entire circumference of a part of the surface of a ring-shaped coil spring. Hollow metal O with double inner and outer coatings
In the ring, the contact portion between the inner cover and the outer cover has a sliding function.

[0010]

According to the present invention constructed as described above, when a displacement occurs between the flanges due to vibration or the like, this displacement is absorbed by the slip between the outer cover and the inner cover, and the outer cover and the inner cover are absorbed. By freely deforming according to the amount of deviation between the flanges without restraining each other, it is possible to prevent the deterioration of the sealing performance by following even a large amount of deviation between the flanges.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 and FIG. 2 show a first embodiment, and a metal hollow O-ring 1 according to the present embodiment is provided with a coil spring 2 bent and formed in a ring shape. Is covered with a metal inner cover 3 having a C-shaped cross section over the entire circumference thereof, and the surface of the inner cover 3 is covered with a metal outer cover 4 having a C-shaped cross section. There is. As a result, the coil spring 2 is double-coated with the inner cover 3 and the outer cover 4.

In this embodiment, the C-shaped openings of the inner jacket 3 and the outer jacket 4 are oriented in the same direction so that a part of the outer circumference of the coil spring 2 is exposed to the outside. However, the C-shaped openings of the inner cover 3 and the outer cover 4 may be located on the opposite sides of the coil spring 2.

Here, as the material of the inner cover 3, a relatively hard metal material such as stainless steel, inconel, monel, or nickel alloy is used, while as the material of the outer cover 4, aluminum, copper, silver. A relatively soft metal material such as is used.

As a result, the biting of the coil spring 2 into the inner cover 3 is suppressed, the stress drop between the pitches of the coil spring 2 is prevented, and the repulsive force of the coil spring 2 is reliably transmitted to the inner cover 3. It is designed to give the outer cover 4 good conformability to the mating metal sealing surface and realize stable sealing performance.

The contact portion between the inner cover 3 and the outer cover 4,
That is, a lubricating layer 5 made of a semi-solid lubricant such as grease is provided between the outer peripheral surface of the outer cover 3 and the inner peripheral surface of the outer cover 4, and the lubricating layer 5 constitutes a sliding mechanism. .

When the lubricating layer (sliding mechanism) 5 is interposed between the abutting portions of the inner cover 3 and the outer cover 4 in this way, when the O-ring 1 is interposed between the flanges to seal the flanges. , Even if there is a gap between the flanges due to vibration,
This shift is absorbed by causing the outer cover 3 and the inner cover 4 to slide along the lubricating layer 5, and the shift amount between the flanges can be obtained without restraining the outer cover 3 and the inner cover 4 from each other. By freely deforming the flanges, it is possible to prevent the deterioration of the sealing performance by following even a large gap between the flanges.

This will be described with reference to FIG. 2. First, as shown in FIG. 2A, when the O-ring 1 is interposed between the flanges 6 and 7, the O-ring 1 is compressed. And is deformed into an elliptical cross section having a short radius h, and contacts one flange 6 at a contact point A and the other flange 7 at a contact point B.

In this state, if a deviation amount δ is generated between the flanges 6 and 7 as shown in FIG. 7B, in order to maintain the sealing property, the O-ring 1 and the flange at the contact A are maintained. 6, the contact between the O-ring 1 and the flange 7 at the contact B must be maintained,
As a result, the O-ring 1 is restored to a flat elliptical cross section with a short radius h '.

At this time, slippage occurs between the inner jacket 3 and the outer jacket 4, so that the inner jacket 3 and the outer jacket 4 are matched with each other by the amount of deviation between the flanges 6 and 7 without being restrained. It can be freely deformed by this, so that the deviation amount δ can be absorbed over a considerably wide range.

That is, in the conventional example in which the inner cover and the outer cover are rigidly connected to each other, the inner cover and the outer cover are constrained to each other, and the individual free deformation of the inner cover and the outer cover is restricted. , As a result, there is a certain limit to the amount of deformation of the entire covering material, and when there is a considerable deviation between the flanges due to vibration, etc.,
There is a certain limit to the amount of misalignment between the flanges that cannot be deformed enough to absorb this amount of misalignment.

On the other hand, in the above embodiment, the allowable amount of deviation between the flanges can be remarkably improved. FIG. 3 is a graph showing the relationship between the shift amount δ and the leakage amount in the above-mentioned embodiment. As comparative examples, a metal solid O-ring, a single-coated O-ring, and a double-coated O-ring are shown. The figure shows the case where sealing is performed.

As is clear from the figure, even when sealing is performed with an O-ring having a double coating which is considered to be most effective for the amount of deviation, the allowable deviation between the flanges is caused. Although the amount is about 0.4 mm, in the present embodiment, this shift amount can be expanded to about 0.8 mm, which is approximately double.

Although the above embodiment shows an example in which the lubricating layer 5 is formed of a semi-solid lubricant such as grease,
The lubricating layer 5 can be formed by a solid lubricant, that is, by sintering or applying a layer of a fixed lubricant on at least one of the outer peripheral surface of the inner cover 3 and the inner peripheral surface of the outer cover 4.

As the solid lubricant, layered inorganic substances such as graphite, molybdenum disulfide, tungsten disulfide, boron nitride and tantalum disulfide, fluororesins such as polyethylene terephthalate (PET) and tetrafluoroethylene (PTFE), nylon, Examples include organic polymers such as polyurethane.

FIG. 4 shows a second embodiment. In this embodiment, at least one of the outer peripheral surface of the inner cover 3 and the inner peripheral surface of the outer cover 4 is mirror-finished so that the inner cover 3 is formed. The O-ring 1 is configured by providing the contact surface 8 between the outer cover 4 and the outer cover 4 with a sliding function.

[0026]

Since the present invention has the above-mentioned structure,
The slippage between the outer cover and the inner cover absorbs the shift between the flanges caused by vibration, etc., and the outer cover and the inner cover can be freely deformed according to the shift amount between the flanges without restraining each other. Even if a large deviation occurs between the flanges due to this, it is possible to reliably absorb the deviation and prevent the sealing performance from deteriorating.

[Brief description of drawings]

FIG. 1 is a half sectional view showing a first embodiment of the present invention.

FIG. 2 is likewise a sectional view showing a state before and after a displacement occurs between the flanges.

FIG. 3 is a graph showing the relationship between the shift amount and the leakage amount in FIG. 2 in comparison with a conventional example.

FIG. 4 is a view corresponding to FIG. 1 showing a second embodiment.

[Explanation of symbols]

 1 O-ring 2 Coil spring 3 Inner cover 4 Outer cover 5 Lubrication layer (sliding mechanism) 6, 7 Flange 8 Abutment surface (sliding mechanism)

Claims (1)

[Claims] 1. A metal hollow O-ring in which a part of the surface of a ring-shaped coil spring is doubly covered with a metal inner cover and outer cover having a C-shaped cross section over the entire circumference thereof. A metal hollow O-ring, characterized in that a sliding function is provided at an abutting portion between the outer cover and the outer cover.