JPH025187Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention includes a sealing elastomer interposed at the joint between a joint pipe inserted into the end of a plastic hose and the inner surface of the hose, and The present invention relates to a sealing structure for a joint of a plastic hose in which a fastener is attached to the joint to prevent leakage of fluid inside the hose.

[Background of the idea]

In recent years, plastic hoses in which plastic is used for the hose inner tube, reinforcing layer, and outer jacket have come into widespread use. This is because plastic hoses are lightweight, have excellent resistance to various oils and chemicals, and are relatively easy to manufacture because they do not require a vulcanization process unlike rubber hoses. However, when plastic hoses are used at high temperatures or repeatedly used at high and low temperatures (including room temperature) at the tightening parts such as fittings, the tightening compressive stress decreases.
It has the disadvantage of causing internal fluid leakage. This occurs because the plastic softens and expands as the temperature rises, and at the same time as the plastic expands, the internal fluid moves from the tightening part to the hose side. Even if the temperature is returned to a low temperature, the transferred outflow will creep and will not return to its original state. Therefore, as this condition is repeated, the internal compressive stress is lost very quickly due to the mechanism of decrease in internal compressive stress of the plastic hose and generation of a gap. Leakage occurs particularly when the internal fluid is gas compared to water or oil.

Therefore, countermeasures have been devised in the past to prevent the above-mentioned fluid leakage. The conventional joint seal structure will be explained with reference to Fig.
(Published in Publication No. 77923). In the same figure,
1 is a plastic hose, and the hose 1 is composed of a hose inner tube 2, a reinforcing layer 3, and an outer cover 4 from the inside. A joint pipe 5 is inserted into the end of the hose 1, and an O-ring-shaped sealing elastomer 6,
6,... intervenes. Then, a fastener 7 is attached to the outer surface of the hose 1, and by caulking portions of the fastener 7 that correspond to the sealing elastomers 6, 6, .
6,... are greatly compressed and deformed, and the repulsive force (initial compressive stress) based on this improves the hermeticity (sealability) of the joint. 8 is the counter hand (not shown)
This is a union for connecting with.

However, as described above, since the sealing elastomers 6, 6, . In particular, in consideration of the magnitude of the pulling force when pressurizing the hose, the caulking part 9 of the fastener 7 is strongly caulked to prevent the joint pipe 5 from being accidentally pulled out from the plastic hose 1, so that it deforms. The amount was also large, and permanent deformation was likely to occur relatively early. Other conventional examples include Japanese Unexamined Patent Publication No. 50-77922 and Utility Model Application No. 47
-9014, etc., but all of them have drawbacks such as insufficient sealing properties and a tendency to cause permanent deformation.

[Purpose of invention]

The present invention was developed in view of the above circumstances, and provides a plastic hose joint seal structure that does not cause permanent deformation in the sealing elastomer over a long period of time, thereby maintaining reliable sealing performance over a long period of time. The purpose is to provide.

[Summary of the idea]

In order to achieve the above object, the present invention provides a funnel-shaped tube expansion section at the end of a plastic hose, and a sealing elastomer is interposed between the tube expansion section and the outer surface of the joint pipe without being significantly deformed. It is characterized by the following points.

[Example of idea]

Hereinafter, the present invention will be explained in detail based on the embodiments shown in the drawings. Fig. 2 is a half-cut sectional view showing the joint seal structure of the plastic hose according to the present invention, Fig. 3 is a sectional view of the end of the plastic hose, Fig. 4 A is a sectional view of the sealing elastomer, and Fig. 4 B is the same. The front view and FIG. 5 show enlarged cross-sectional views of essential parts of the same seal structure. In these figures, the same reference numerals as in FIG. 1 above indicate the same parts. In the present invention, a funnel-shaped expanded tube portion 10 is provided at the end of the plastic hose 1. An O-ring-shaped sealing elastomer 6 is immovably interposed between the inner surface of the distal end of the expanded tube portion 10 and the outer surface of the joint tube 5. Here, as a structure that makes the sealing elastomer 6 immovable, a groove 11 (this groove is not necessary) and a stopper 12 are provided around the joint pipe 5, and the elastomer 6 is lightly attached to the expanded pipe part 10 and the stopper 12. It is configured to be pressed into contact. Fastener 7
is caulked at a position where the elastomer 6 is not present, and the tightening pressure is concentrated while avoiding the elastomer 6 position. As a result, the sealing elastomer 6 is not significantly deformed. The material for the sealing elastomer 6 may include fluoro rubber, silicone rubber, nitrile rubber, etc., but it is preferable to select it as appropriate depending on usage conditions such as temperature and type of fluid.

Next, the operation will be explained with reference to FIGS. 2 and 5. If fluid enters between the hose inner tube 2 and the joint tube 5 and causes internal leakage toward the end of the hose, it will be blocked by the sealing elastomer 6. If the fluid continues to leak further, the leakage pressure P increases to the elastomer 6.
join. Then, the degree of deformation of the elastomer 6, which had not been significantly deformed until then, increases due to the leakage pressure P, and due to the partial pressure and g, it comes into strong pressure contact with the expanded pipe portion 10 and the stopper 12, improving sealing performance. do. That is, the leakage pressure P
A self-sealing function is developed that improves the sealing performance as the value increases.

[Effect of idea]

As described above, the present invention provides a funnel-shaped tube expansion section at the end of a plastic hose, and interposes a sealing elastomer immovably between the inner surface of the tip of the tube expansion section and the outer surface of the joint tube, and This is a plastic hose joint seal structure in which a fastener is attached in such a manner that its tightening pressure is concentrated while avoiding the position of the sealing elastomer. Therefore, unlike the conventional sealing elastomer, the sealing elastomer is not subjected to large deformation at the initial stage, so that permanent deformation does not occur over a long period of time. Further, due to the self-sealing function in which the sealing performance improves as the leakage pressure increases, the permanent deformation does not occur, and reliable sealing performance can be maintained over a long period of time. Further, according to the present invention, it is possible to satisfy the optimum compression ratio (5 to 30%) of a general rubber O-ring, and from this point of view as well, sealing performance can be ensured. Also,
Since the diameter of the sealing elastomer can be set large due to the expanded tube structure, permanent deformation is less likely to occur from this point of view as well.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view showing a conventional example, Fig. 2 is a half-sectional view showing the joint seal structure of a plastic hose according to the present invention, Fig. 3 is a cross-sectional view of the end of the plastic hose, and Fig. 4 A cross-sectional view of the sealing elastomer, FIG. 1...Plastic hose, 5...Joint pipe, 6
...Sealing elastomer, 7...Tightening tool, 10
...Expansion section.

Claims (1)

[Scope of utility model registration request] A plastic hose joint comprising a sealing elastomer interposed at the joint between the outer surface of a joint pipe inserted into the end of the plastic hose and the inner surface of the hose, and a fastener 7 attached to the outer surface of the hose. In the partial seal structure, a funnel-shaped expanded tube portion is provided at the end of the hose, and the sealing elastomer is interposed between the inner surface of the distal end of the expanded tube portion and the outer surface of the joint tube, and the tightening tool 7 A joint seal structure for a plastic hose, characterized in that the caulking position of the sealing elastomer is avoided from the position of the sealing elastomer.