JPH041408Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an O-ring, and more particularly to an improvement in an O-ring in which an outer spring material is integrally composited with a polyurethane rubber layer.

[Conventional technology]

As is well known, there are various performances required of O-rings, some of which are as follows.

One is to have a predetermined tightening force in the direction of the center of the ring when the ring-shaped O-ring is applied to the object to which it is applied.

That is, it must have a predetermined tensile strength.

The reason is that the tightening force does not decrease significantly over time. In order to solve these problems, various O-rings have been developed and put into practice. In this case, we are trying to meet the above requirements by mainly studying the selection of materials, cross-sectional shapes, etc. while considering the relationship with the application target.

However, in the past, when looking at materials, most of them were O.
The cross section of the ring consists of a single layer of the same material.

Looking at this single-layer product, we found that conventional O
A ring is preferred.

That is, polyurethane rubber gives a certain elongation at room temperature or in hot air, and at this time, the stress decreases over time, that is, the stress relaxation value is suppressed to a low level. Therefore, as it is used, the degree of decrease in tightening force is small.

However, if we try to increase or decrease the tightening force itself, the predetermined tensile strength must be changed, and in this case, the cross-sectional area must be increased or decreased. The cross-sectional shape of the ring becomes unnecessarily thick or thin, which tends to be inconsistent with the mounting conditions of the product to which it is applied. More specifically, there is no degree of freedom in design.

Therefore, a composite of metal material and polyurethane rubber was proposed.

[The problem that the idea aims to solve]

According to the above-mentioned product made of metal material and polyurethane rubber, the idea is not to change the tensile strength only by increasing or decreasing the cross-sectional area, but by changing the tensile strength by various combinations of metal material and polyurethane rubber, depending on the requirements.
Although the tensile strength can be adjusted, the conventional technology simply has polyurethane rubber built into the metal material, and for this reason, it is difficult to adjust the specific tightening force in the direction of the center of the ring. It was not available to technology.

It was also proposed that a ring-shaped coil spring was embedded in polyurethane rubber to integrate the polyurethane rubber and the ring-shaped spring.
No. 1912) could not meet the requirement to expose the annular coil spring to the outside.

Therefore, the purpose of the present invention is to create an O-ring that produces the required tightening force in the direction of the center of the ring, and to provide an O-ring made of polyurethane rubber that has a tensile stress relaxation value below a certain level. By taking advantage of the fact that the originally set tightening force does not decrease much, it is possible to maintain the sealing properties of the target object for a long period of time.
When changing the shape to suit various characteristics such as shape and use, it is easier to change the cross-sectional area without simply increasing or decreasing the cross-sectional area, and it is easier to attach to the object of application, and furthermore, a ring-shaped coil spring is to provide an externally exposed O-ring.

[Means to solve problems]

The present invention has the following technical means to achieve the above object. That is, to explain using the reference numerals used in the attached drawings corresponding to the embodiments, in the O-ring made of polyurethane rubber, which is formed by casting polyurethane rubber into the hollow interior of the spring and is integrated with the spring, the above-mentioned The spring 2 is a ring-shaped coil, and inside the spring 2 is a polyurethane rubber 3.
is cast molded so that the outside of the spring 2 is exposed to the outside, and the polyurethane rubber 3 is inserted into the gap 7 between the coil valleys inside the spring 2 and is integrated with the spring 2. This is a distinctive O-ring.

[Effect]

With this configuration, when the present invention is used, the O-ring 1 is formed in a ring shape, and the O-ring 1
When applied to the object to which polyurethane rubber 3 is applied, the stress relaxation value can be maintained below a low standard value over time, so the O
The ring 1 as a whole can maintain a tightening force against the object. Also, by using the spring 2 and polyurethane rubber 3 in combination, they work together with the spring 2, so the tightening force in the center direction of the ring-shaped O-ring 1 can be increased. I can do it.

Therefore, when increasing or decreasing the tightening force as required by using the polyurethane rubber 3 in combination, it is necessary to appropriately select the material, wire diameter, pitch, etc. of the spring 2 without changing the cross-sectional area of the polyurethane rubber 3. The above tightening force can be increased or decreased.

Furthermore, since the range of the initial tension of the spring 2 is within the range in which the O-ring 1 is normally used, this can be easily used. In terms of structure, the spring 2 can be an O-ring exposed to the outside.

〔Example〕

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings FIGS. 1 to 4.

In the figure, reference numeral 1 indicates an O-ring body, which is formed into a ring shape and is composed of a spring 2 as an outer layer and a polyurethane rubber 3 as an inner layer.

The outer layer spring 2 has a circular cross-sectional shape, and by injecting polyurethane rubber 3 into the hollow inside of the outer layer spring 2, the outer layer spring 2 and the inner layer polyurethane rubber 3 are compositely integrated. It is not just a case of inserting a fine cylindrical piece of polyurethane rubber into the hollow interior of the spring 2. As another example, as shown in FIGS. 5 and 6, it is conceivable to use a spring 2 having a chevron-shaped or trapezoidal cross-sectional shape.

An example of the manufacturing method for compositing the inner and outer layers described above is to centrifugally cast polyurethane rubber 3 into the hollow interior of the outer layer spring 2.

Then, by casting, the inner surface 5 of the spring 2 and the polyurethane rubber 3 are bonded together as shown in FIG.
The surfaces 4 of the pitches are in close contact with each other, and as shown in FIG. A portion 6 is formed.

Therefore, when the O-ring main body 1, which is formed in a ring shape and is compositely integrated with the spring 2 and the polyurethane rubber 3, is pulled on both sides, the spring 2 of the inner and outer layers
A tensile force is generated throughout the polyurethane rubber 3, and a tensile stress, that is, a force that attempts to return to its original state, is generated corresponding to the tensile force. This tensile stress occurs throughout the inner and outer layers, that is, the spring 2 and the polyurethane rubber 3.

There are various properties of the polyurethane rubber 3, but when viewed in relation to the present invention, they are values at which stress decreases over time when given a certain elongation at room temperature or in hot air...that is, stress relaxation values. It is noteworthy that the

In particular, by selecting materials, etc., the standard value of the tensile stress relaxation value can be set to 20% or less when the elongation rate is 5% and the temperature is 120°C x 100 hours.

In the above, what is the tensile stress relaxation value?
According to a test method based on JISK6301, vulcanized rubber is held at a constant elongation at room temperature or in hot air, and the stress is measured as the stress decreases over time. Therefore, the value of the tightening force of the entire O-ring 1 decreasing over time is not large.

That is, the tightening force of the entire ring-shaped O-ring 1 in the direction of the center of the ring can be maintained for a long period of time.
Further, the spring 2 has a characteristic that its initial tension is large. Moreover, the initial tension is within the normal range of the O-ring 1. In other words, by applying spring 2,
The tightening force in the center direction of the ring-shaped O-ring 1 can be increased. Therefore, it is easy to apply the entire O-ring 1 to the required tightening force and tensile stress.

This is because by making the material, wire diameter, and pitch of the spring 2 variable, the tightening force, etc., can be adjusted to meet the requirements.

By the way, O consisting simply of a single layer of polyurethane rubber
Rings have the above-mentioned stress relaxation properties, but if you try to increase or decrease the tightening force itself according to the requirements of the product itself, you have to constantly increase or decrease its cross-sectional area, and it depends on the installation conditions of the target object. Difficult to match. That is, the degree of freedom in designing the object to which it is applied may be restricted.

However, the above-mentioned O-ring 1 is a ring-shaped structure in which the outer layer spring 2 is integrally composited with polyurethane rubber 3 in the hollow interior, and the material, wire diameter, pitch, etc. of the spring 2 are Since the clamping force can be made variable, the clamping force can be appropriately selected without changing the cross-sectional area of the polyurethane rubber 3, that is, according to the requirements of the object to which it is applied. Therefore, the degree of freedom in design is less limited.

Next, a usage example of this embodiment will be described in detail. As shown in FIG. 7, this application example shows the use as an O-ring 1 for fixing a globe 8 in a nuclear power plant.

That is, when inserting the O-ring 1 into the glove 8 that is the object of sealing, the fixing ring 11 that fixes the glove port 9 and the inner ring 10 is removed and the glove 8 on the inner ring 10 and the O-ring 1 are inserted. In this case, the O-ring 1 itself is required to have sufficient tightening force and durability in order to achieve a complete seal. Furthermore, it is required to maintain the tightening force over a long period of time. In such cases, this invention satisfies the requirements. In addition,
Needless to say, it can be used for sealing positions in various industrial equipment.

[Effect of idea]

As detailed above, the present invention utilizes the advantages of polyurethane rubber O-rings, that is, the tensile stress relaxation value is below a certain level, and the initially set tightening force does not decrease much. While the sealing properties of objects can be maintained for a long period of time, the quality of the spring,
That is, by taking advantage of the high initial tension, it is possible to increase the tightening force against the object to which it is applied. Therefore, when changing the tightening force itself in response to various characteristics such as the type, shape, and usage of the object to which it is applied, it is possible to change the tightening force itself without simply increasing or decreasing the cross-sectional area of the polyurethane rubber. This can be easily changed by changing the spring material, wire diameter, pitch, etc., and can be easily installed in accordance with the conditions of the object to which it is applied. Therefore, it is possible to provide an O-ring having such characteristics and having a structure in which the spring is exposed to the outside.

[Brief explanation of the drawing]

The accompanying drawings show an embodiment of the present invention; FIG. 1 is an overall view including a partial cross section, FIG. 2 is an enlarged view of arrow P in FIG. 1, and FIG. 4 is a sectional view taken along the Y-Y line in FIG. 1, FIGS. 5 and 6 show modified examples, FIG. FIG. 7 shows a cross-sectional view showing an example of use of the trapezoidal one. In addition, in the figure, 1... O-ring body, 2... Spring,
3...Polyurethane rubber and 7...Gap are shown, respectively.

Claims (1)

[Claims for Utility Model Registration] In a spring made of polyurethane rubber in which polyurethane rubber is cast into the hollow interior of the spring and is integrated with the spring; A polyurethane rubber 3 is cast inside the spring 2 so that the outside of the spring 2 is exposed to the outside, and the polyurethane rubber 3 is inserted into the gap 7 between the coil valleys inside the spring 2. An O-ring characterized by being integrated with a spring 2.