JPH1163340A - Flexible pipe fittings - Google Patents

Abstract

(57) [Problem] To provide a joint for a flexible pipe excellent in gas tightness and connection workability. SOLUTION: A tubular joint main body 1 and an elastic tightening ring 18 arranged inside the joint main body 1 and, when compressed in an axial direction, its inner diameter is reduced and the outer periphery of a flexible pipe 4 is airtightly tightened. And a pressing nut 2 that compresses the elastic tightening ring 18 in the axial direction when it is screwed into the joint body 1 and rotated. The elastic fastening ring 18 is formed of an elastomer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible pipe joint to be attached to an end of a flexible pipe used for a gas pipe or the like.

[0002]

2. Description of the Related Art In recent years, bellows-shaped thin metal tubes made of stainless steel, copper, etc., so-called flexible tubes, have been frequently used in order to enhance the ease and reliability of gas piping. This type of flexible pipe has the advantage of being easy to bend despite the high mechanical strength against crushing due to the formation of a bellows-like fold, but on the other hand, it is difficult to connect to the joint and the sealing degree of the joint is low. There is also a problem that it tends to decrease.

[0003] Conventionally, as joints for flexible pipes, Japanese Unexamined Patent Publications Nos. 7-145894 and 8-1 have been proposed.
One such as disclosed in Japanese Patent No. 59350 is proposed. Each of these flexible pipe joints includes a cylindrical joint main body, a nut screwed to the rear end thereof, and a retaining ring engaged with the front end of the nut and disposed in the joint main body. The retaining ring locks the concave portion of the flexible tube, compresses the distal end face of the flexible pipe, and mainly seals the gas with the distal end face.

In order to connect a flexible pipe to these flexible pipe joints, first, a distal end of the flexible pipe is inserted from the rear end side of the nut, and then the nut is tightened to advance the retaining ring. Then, the distal end of the flexible pipe locked by the retaining ring is crushed in the axial direction by one or two peaks of the bellows inside the joint body to become a flange, and the gas is sealed at the distal end of the pipe. By locking the flange portion with the retaining ring, the flexible pipe is firmly fixed so as not to come off from the joint.

[0005]

By the way, the joint for a flexible pipe as described above has a structure in which the retaining ring is advanced by rotating the nut, and the distal end of the flexible pipe made of metal is crushed by the advancing force. Because
There is a problem that it takes a lot of force to rotate the nut and the workability is poor.

Further, the retaining ring is only involved in retaining the flexible tube, and the sealing property is as follows.
Since the distal end of the flexible pipe is secured by abutment with a seal provided inside the joint body, if the distal end of the flexible pipe to be connected has burrs or scratches, the sealing performance may not be sufficiently secured. Therefore, in such a case, it is necessary to shape the cut surface of the flexible tube, and the workability is also poor in this regard.

On the other hand, in Japanese Patent Application Laid-Open No. 7-110088, a cylindrical sealing material is disposed inside a joint body, and after inserting a flexible pipe through the sealing material, the joint can be moved in the axial direction with respect to the joint body. The attached pressing member is moved. Thereby, the sealing material is compressed and expanded inward, and is fitted into the concave portion on the outer periphery of the flexible pipe, thereby ensuring the sealing performance with the outer circumference of the flexible pipe. However, in this configuration, it merely secures the sealing property, and in order to obtain the effect of preventing the flexible tube from coming off, it is necessary to separately use some kind of stopping means such as a stopper ring. There is a problem that it takes time and effort.

An object of the present invention is to provide a flexible pipe joint which can solve the above-mentioned problems and is excellent in connection workability.

[0009]

In order to solve the above problems, a joint for a flexible pipe according to the present invention is provided with a tubular joint body into which a flexible pipe is inserted, and is disposed inside the joint body and has an inner periphery. An elastic tightening ring having a concave and / or convex portion formed on a surface thereof so as to be capable of engaging with the unevenness of the outer peripheral surface of the flexible tube; and an elastic tightening ring which is screwed into the joint body and rotated. A pressing body that compresses the ring in the axial direction, wherein the elastic tightening ring is formed at least in part of an elastic body such as a thermoplastic elastomer or rubber, and is compressed in the axial direction by the pressing body. It is characterized in that the inner diameter is reduced so that the outer periphery of the flexible tube is airtightly tightened.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] FIG. 1 is a partial sectional view showing a first embodiment of a joint for flexible pipes according to the present invention. The flexible tube 4 shown in this figure is a metal tube made of stainless steel, copper, or a copper alloy formed in a bellows shape over its entire length, and has a protective outer cover 6 made of plastic or the like over its entire length. Are formed. However, the subject of the present invention is not limited to the illustrated flexible tube, and is applicable to, for example, a simple tubular flexible tube having no bellows or a flexible tube having no protective sheath 6.

The joint for a flexible pipe according to the first embodiment includes a cylindrical joint body 1 having an inner diameter through which the flexible pipe 4 can be inserted. Is formed, and can be screwed into a female screw portion of a mating member (not shown). On the other hand, a female screw portion 12 is formed on the inner peripheral surface of the rear end portion of the joint body 1, and a male screw portion 14 formed at the tip of the pressing nut (pressing body) 2 is screwed into the female screw portion 12. Have been combined. Thus, when the pressing nut 2 is rotated, the pressing nut 2 moves in the axial direction.

An annular convex portion 16 is formed coaxially at the tip of the pressing nut 2, and when the pressing nut 2 is tightened, the annular convex portion 16 uniformly presses a washer 50 described later. The outer periphery of the rear end of the pressing nut 2 is formed in a hexagonal shape, and a packing 28 for tightening the protective sheath 6 of the flexible tube 4 to increase the airtightness is accommodated inside the rear end. . The O-ring 15 is attached to the outer periphery of the relatively thin distal end of the pressing nut 2, while the O-ring 15 is attached to the entire inner periphery of the rear end of the joint body 1 when the pressing nut 2 is tightened. An O-ring housing groove 13 into which the ring 15 is fitted is formed.

An annular partition wall 10 protruding inward is formed in a central portion of the joint body 1 in the longitudinal direction.
The inner diameter of the partition wall 10 is set smaller than the minimum outer diameter of the flexible pipe 4, and the distal end of the flexible pipe 4 inserted from the rear of the joint body 1 hits the partition wall 10.

A cylindrical elastic tightening ring 18 is provided on the rear side of the partition wall 10 so that the front end thereof contacts the partition wall 10.
Is housed. The elastic tightening ring 18 is formed of a material that can be elastically deformed into a soft rubber shape, for example, a thermoplastic elastomer or rubber, and has an inner peripheral surface formed on the outer periphery of the flexible tube 4 as illustrated in FIG. An annular concave portion 54 and an annular convex portion 52 having shapes complementary to the annular convex portion 56 and the annular concave portion 58, respectively, are formed. The concave and convex portions on the inner peripheral surface of the elastic tightening ring 18 not only increase the adhesion to the flexible pipe and the airtightness at the time of tightening, but also remarkably increase the pull-out locking force on the concave and convex portions 52 and 54 of the flexible pipe 4. improves. This elastic tightening ring 18
Withdrawal of the flexible tube 4 is completely prevented by the inner surface irregularities 56 and 58, and the joint of the present invention becomes practical. The cross-sectional shape of the uneven portion on the inner surface of the elastic tightening ring 18 is such that the elastic tightening ring 18 is elastically deformed at the time of tightening.
It does not necessarily have to be a shape completely complementary to the outer peripheral uneven portion of the flexible tube 4.
Any shape may be used as long as the shape can be inserted by the elastic deformation of 2 and the gas can be sealed and the pull-out can be locked at the time of tightening.

As shown in FIG. 2, when the outer diameters of the annular convex portion 56 and the annular concave portion 58 of the flexible tube 4 are R3 and R4, the annular convex portion 52 and the annular shape of the elastic tightening ring 18 in a free state. It is preferable that the inner diameters R1 and R2 of the recess 54 are determined so as to satisfy the following relationship. R4 ≦ R1 ≦ R3 ≦ R2 By satisfying such a relationship, the flexible pipe 4
Can be inserted into the elastic tightening ring 18 in a free state with a suitable resistance, and the tightening force of the flexible pipe 4 by the elastic tightening ring 18 becomes appropriate. However,
When the annular convex portion 52 is sufficiently soft, slightly R4
> The flexible tube 4 can be inserted even if R1 is set,
It is possible to improve gas tightness.

The elastomer or rubber used as the material of the elastic tightening ring 18 is not limited, but includes polyester, acrylonitrile butadiene styrene (ABS), acrylate styrene acrylonitrile, cellulose acetate, ethylene vinyl acetate, polyamide, polycarbonate, For a thermoplastic elastomer selected from polyethylene, polymethyl methacrylate, polyacetal, polypropylene, polyphenylene ether, polystyrene, polybutylene terephthalate, urethane-based thermoplastic elastomer, polyvinyl chloride, styrene acrylonitrile, polyethylene terephthalate, polyvinyl acetate, polyphenylene sulfide, etc. A single type or a blend can be exemplified, and it is particularly preferable to use it as a sealant or packing material. There polyurethane, polyamide, and thermoplastic elastomer polyolefin, for example, polyester or a blend of styrene-ethylene-butadiene-styrene (SEBS) and styrene-ethylene-propylene-styrene.

Although the hardness of the elastomer is not limited, it is preferably JIS Shore A hardness of 40 to 90, more preferably 50 to 80. If the JIS Shore A hardness is within the above range, the elastic tightening ring 18
, The tightening force on the flexible pipe 4 becomes appropriate, and both the sealing of the gas and the locking of the extraction are reliably performed.

Although the length of the elastic tightening ring 18 in the axial direction is not limited, in this embodiment, the length is set to about three wavelengths of the bellows of the flexible tube 4. The thickness of the elastic tightening ring 18 in the radial direction is such that the outer circumferential surface of the elastic tightening ring 18 abuts or is lightly pressed against the inner circumferential surface of the joint body 1 in a natural state in which the elastic tightening ring 18 is not elastically deformed. The flexible tube 4 is located in the vicinity and can be pressed into the elastic tightening ring 18 with some resistance. Then, when the elastic tightening ring 18 is tightened in the axial direction, the elastic tightening ring 18 needs to be thick enough to generate a swelling pressure in the inner diameter direction. The minimum thickness required for generating the bulging pressure due to this elastic deformation is the hardness of the elastic tightening ring 18, the axial length,
And the inner peripheral surface shape of the joint body 1.

An elastic tightening ring 1 is provided inside the joint body 1.
An annular washer 50 may be coaxially arranged between the pressing nut 8 and the pressing nut 2. The washer 50 is preferably made of metal or plastic harder than the elastomer forming the elastic tightening ring 18. The outer diameter of the washer 50 is slightly smaller than the outer diameter of the elastic tightening ring 18 pressing portion on the inner periphery of the joint body 1, and the inner diameter is slightly larger than the maximum outer diameter of the flexible pipe 4. Washer 50 may be annular or C-shaped.

As shown in FIG. 1, a removable spacer 32 is provided between the joint body 1 and the pressing nut 2 to keep the initial (before use) screwing amount of the two constant. Good. If the pressing nut 2 is excessively tightened into the joint body 1 before use, even if the flexible pipe 4 is inserted,
This is because the diameter of the elastic tightening ring 18 cannot be increased. The spacer 32 is, for example, a C-shaped plastic ring, and it is preferable that the spacer 32 can be easily removed from the flexible pipe joint when connecting the flexible pipe 4.

An elastic tightening ring 1 is provided on the wall of the joint body 1.
One leak detection hole 29 extending from the outer wall surface to the inner wall surface is formed closer to the pressing nut 2 than 8. This leak detection hole 29 is used for inspection of gas leakage from damage caused to the flexible pipe 4 due to an earthquake or an accident. The leak detection hole 29 is common to all embodiments exemplified in this specification.

Next, a method of using the flexible pipe joint having the above configuration will be described. First, the flexible tube 4 is vertically cut along the concave portion on the outer peripheral surface, and further, the protective outer cover 6 is vertically cut at a fixed distance from the cut end. The reason for removing the protective sheath 6 at the end of the flexible tube 4 is as follows.
This is because the flexible tube 4 is firmly fixed using the unevenness of the flexible tube 4. The cutting position of the protective shell 6 is
A position slightly away from the end of the flexible tube 4 by a distance slightly larger than the sum of the axial lengths of the elastic tightening ring 18 and the washer 50 is set.

The end of the flexible pipe 4 from which the protective sheath 6 has been removed is inserted coaxially from the rear end of the flexible pipe joint. Then, the elastic tightening ring 1 is
8, the two annular projections 52 of the elastic tightening ring 18 are fitted into the two annular recesses 58 at the distal end of the flexible tube 4 respectively, as shown in FIG. Becomes When the state shown in FIG.
2 is removed and the pressing nut 2 is screwed into the joint body 1.

Then, the annular projection 16 formed at the tip of the pressing nut 2 pushes the washer 50 forward, and the elastic tightening ring 18 is compressed in the axial direction. Elastic tightening ring 18
Is restricted by the inner peripheral wall surface of the joint body 1, the inner peripheral surface of the elastic tightening ring 18 protrudes inward, and closely adheres to the outer peripheral surface of the flexible pipe 4 to obtain a high sealing property. At the same time, since the outer peripheral portion of the flexible pipe 4 is tightened over the entire circumference, the flexible pipe 4 is prevented from coming off.

The O-ring 15 is provided in the O-ring housing groove 13.
And the boundary between the joint body 1 and the pressing nut 2 is sealed to obtain high airtightness. The O-ring 15 and the packing 28 ensure airtightness, and the joint body 1
Is formed with a leak detection hole 29, so that if the flexible pipe 4 should be cracked or damaged and a gas leak occurs, the leaked gas flows between the flexible pipe 4 and the protective sheath 6. It passes through the joint body 1 and is detected from the leak detection hole 29. Therefore, the gas leak can be reliably detected by bringing the gas detector close to the leak detection hole 29.
The leak detection hole 29 can be formed in any of the embodiments described later.

According to the flexible pipe joint having the above structure, the elastic tightening ring 18 is operated by operating the pressing nut 2.
Is compressed and the inner peripheral surface is expanded to squeeze and fix the flexible pipe 4 without gaps.
Does not need to be crushed in a flange shape, and an excessive force is not required for the rotation of the pressing nut 2.

Further, by reducing the inner diameter of the compressed elastic tightening ring 18, not only the effect of preventing the flexible tube 4 from coming off is obtained, but also the space between the inner peripheral surface of the joint body 1 and the outer peripheral surface of the flexible tube 4 is improved. Since it is completely sealed, it is not necessary to separately seal the distal end face of the flexible tube 4,
The cut surface of the flexible tube 4 may have some irregularities. Therefore, since the shaping of the cut surface of the flexible tube 4 can be omitted, the connection work can be facilitated from this point as well.

FIGS. 3 to 11 are sectional views showing modified examples of the elastic tightening ring 18. The elastic tightening ring 18 of FIG. 3 has a washer 50 separate from the elastic tightening ring 18.
Instead of providing the inner surface of the elastic tightening ring 18 which is in contact with the pressing nut 2, the surface of the elastic tightening ring 18 is close to the surface layer or the surface.
An annular disk portion 60 made of a relatively hard material is embedded. The disk portion 60 may be embedded by placing a metal washer in a mold at the time of forming the elastic tightening ring 18, or may be formed by two-color molding using a relatively hard resin. It may be.
When such a disk portion 60 is integrally provided in the elastic tightening ring 18, the washer does not rattle inside the joint body 1, and the pressing of the elastic tightening ring 18 by the pressing nut 2 in the axial direction is prevented. This is advantageous in that it is performed evenly and the inner diameter of the elastic tightening ring 18 swells accurately.

The elastic tightening ring 18 shown in FIG.
Instead of providing 0, an annular disk portion 62 made of a relatively hard material is integrally formed inside or near the end surface of the elastic tightening ring 18 which comes into contact with the pressing nut 2. . The disk portion 62 may be a washer made of metal or the like adhered to the end surface of the elastic tightening ring 18 or may be formed by two-color molding using a relatively hard resin. . Even when such a disk portion 62 is formed integrally with the elastic tightening ring 18, in addition to the equalizing effect at the time of tightening, the washer does not rattle inside the joint body 1 and the pressing nut 2 The pressing in the axial direction of the elastic tightening ring 18 is uniformly performed by the elastic tightening ring 1.
8 has an advantage that the inner diameter swelling is performed accurately. Further, in the elastic tightening ring 18 of FIG. 4, each of the annular convex portions 52 is formed integrally with a relatively harder elastomer than the other portions to form a hard portion 64 having a semicircular cross section. This is the second feature. By forming such a hard portion 64, the effect of preventing the flexible tube 4 from coming off can be significantly improved, and damage to the inner periphery of the elastic tightening ring 18 when the flexible tube 4 is inserted can be prevented.

The elastic tightening ring 18 shown in FIG.
2 is characterized in that only the respective tip portions are integrally formed of an elastomer relatively harder than the other portions to form a hard portion 64 having a crescent cross section. Also in this case, the flexible tube 4 can be formed by forming the hard portion 64.
And at the same time, prevents the inner circumference of the elastic tightening ring 18 from being damaged when the flexible tube 4 is inserted.

The elastic tightening ring 18 shown in FIG.
2 is characterized in that each tip portion is integrally formed of an elastomer that is relatively harder than the other portions, and is formed as a hard portion 64 having a cross section projecting outward. Also in this case, by forming the hard portion 64, the effect of preventing the flexible tube 4 from falling off can be enhanced, and at the same time, the inner peripheral portion of the elastic tightening ring 18 can be prevented from being damaged when the flexible tube 4 is inserted.

The elastic tightening ring 18 shown in FIG.
2, a ring-shaped hard portion 66 made of metal or hard resin is embedded coaxially with the elastic tightening ring 18. Also in this case, by forming the hard portion 66, the effect of preventing the flexible tube 4 from falling off and the effect of preventing the inner circumference of the elastic tightening ring 18 from being damaged can be enhanced. In this case, the surface remains a soft elastic body, so that the airtightness and adhesion are good, and the flexible tube 4 can be easily inserted.

The elastic tightening ring 18 shown in FIG.
2 is characterized in that a hard portion 66 made of a metal or a hard resin having a ring shape with a different cross section is buried coaxially with the elastic tightening ring 18 in each of the insides. Also in this case, the effect of preventing the flexible tube 4 from falling off can be enhanced by forming the hard portion 66. In this case, when the flexible tube 4 is to be pulled out, an axial shearing stress acts on the elastic tightening ring 18. However, when the flexible tube 4 is expanded in the radial direction as the hard portion 66 in FIG. Is preferred because it increases the shear drag of the steel. The hard part 66 of FIGS. 7 and 8
, The hard portion strengthens the shearing resistance of the annular convex portion 52,
The elastic tightening ring 18 is elastically tightened in consideration of enhancing the tightening of the flexible tube 4 by facilitating the expansion in the inner diameter direction by compressing the elastic tube 18 in the axial direction, and improving the gas tightness by tight contact between both ends. The cross-sectional shape of the ring 18 should be determined.

The elastic tightening ring 18 shown in FIG.
A ring-shaped hard portion 66 made of metal or hard resin is buried coaxially with the elastic tightening ring 18 in each of the insides of the elastic member 2.
An annular hard portion 68 made of a relatively hard elastomer is integrally formed at each position corresponding to No. 4. In this case, the rigid portion 66 can enhance the retaining effect of the flexible tube 4, and the formation of the rigid portion 68 restricts the displacement of the elastomer when the elastic tightening ring 18 is compressed, as shown by an arrow. The hard portion 66 can be more remarkably displaced inward. Therefore, insertion of the flexible tube 4 is facilitated, and resistance to pulling out increases.

In the elastic tightening ring 18 shown in FIG. 10, only an annular portion of the annular convex portion 52 near the pressing nut 2 is integrally formed of a resin 64 having a relatively smaller coefficient of friction than other portions. It is characterized by. According to this configuration, when the flexible tube 4 is pushed into the elastic tightening ring 18, the annular convex portion 56 of the flexible tube 4 is
When the flexible tube 4 is subjected to a pulling-out force while smoothly coming into the annular concave portion 54 by contacting the same, the drawing-out force can be supported by a resin having a large friction coefficient. Therefore, the insertion of the flexible tube 4 becomes easy, and the pull-out resistance increases.

The elastic tightening ring 18 shown in FIG. 11 is characterized in that an annular hard portion 69 made of an elastomer relatively harder than other portions is integrally formed on the surface of the annular recess 54. In this case, since the hard portion 69 firmly grips the convex portion 56 of the flexible tube 4 over the entire circumference, the pull-out resistance of the flexible tube 4 can be increased. Moreover, in this case, the flexible tube 4 can be easily inserted, the elastic tightening ring 18 is hardly broken even when a strong pulling force is applied, and the self-sealing recovery force is strong. In addition, at the time of forming the elastic tightening ring 18, a forced split die can be used, which has the advantage of mass production at low cost.

[Second Embodiment] FIG. 12 shows a second embodiment of the present invention.
1 shows an embodiment. In this embodiment, a tapered surface 18A whose outer diameter decreases toward the front is formed on the outer periphery of the elastic tightening ring 18 and the inner periphery of the joint body 1 is located at a position corresponding to the tapered surface 18A. And a tapered surface 1A whose generatrix is parallel to the tapered surface 18A. Since the respective contact surfaces of the elastic tightening ring 18 and the joint body 1 are tapered surfaces 18A, 1A, when the pressing nut 2 is tightened to press the elastic tightening ring 18, the elastic tightening ring 18 is pressed. Since the function of increasing the diameter by sliding the member 18 forward is also obtained, the tightening force of the flexible tube 4 by the elastic tightening ring 18 can be further increased. In addition, it is also possible to provide the tapered surface 1A only on the inner circumference of the joint main body 1 and make the outer circumference of the elastic tightening ring 18 simply cylindrical. Even when only the inner peripheral side of the joint body 1 is tapered, if the taper angle is small, the elastic tightening ring 18 behaves in a similar manner with the rotation of the pressing nut 2. From the viewpoint of cost reduction and workability, only the inner peripheral side of the joint body 1 may be a tapered surface.

[Third Embodiment] FIG. 13 shows a third embodiment of the present invention. In the above-described second embodiment, a simple conical tapered surface is formed on the inner periphery of the joint main body 1. Instead, in the third embodiment, a stepped portion having a two-step tapered portion 1B is provided. The surface 1A is formed. The outer peripheral surface 18A of the elastic tightening ring 18 may have a shape complementary to the stepped surface 1A, or may be a simple cylindrical surface if the taper amount is small. In this embodiment, a ring-shaped hard portion 66 made of metal or hard resin is embedded coaxially with the elastic tightening ring 18 in each annular convex portion 52 of the elastic tightening ring 18. According to such a configuration, when the elastic tightening ring 18 is compressed by the pressing nut 2, the radially inward stress generated at the position of the two-step tapered portion 1B effectively displaces the hard portion 66 inward. Then, the flexible pipe 4 is tightened. Therefore, it is possible to further prevent the pull-out.

FIG. 14 shows a modification of the elastic tightening ring 18 applicable to any of the embodiments. The elastic tightening ring 18 described so far is integrally formed so as to form a cylindrical shape. However, as shown in FIG. 14, the elastic tightening ring 18 may be divided into two along a plane including an axis. .
Furthermore, in order to facilitate the assembly, the two divided members may be connected in a hinge shape, and the protrusion 70 and the concave portion 72 that fit each other may be formed on the contact surface of each member.

FIG. 15 shows a modification of the washer 50 which can be combined with any of the embodiments. The washer 50 has a structure in which arcuate portions 50A made of a relatively hard material are connected by a member 50B such as an elastic resin or a spring. Such a washer 5
0, the elastic nut 1
When compressing the elastic ring 8, the washer 50 is also reduced in diameter as the diameter of the elastic tightening ring 18 is reduced, so that the washer 50 does not hinder the reduction in diameter of the elastic tightening ring 18.

[Fourth Embodiment] FIG. 16 shows a fourth embodiment. In this embodiment, a convex portion 16 having a semicircular cross section is formed at the tip of the pressing nut 2.
It is characterized in that the projection 16 is directly sunk into the rear end face of the elastic tightening ring 18. According to such a configuration, it is possible to effectively increase the internal pressure of the elastic tightening ring 18 with the advance of the pressing nut 2, so that the rotational force applied to the pressing nut 2 can be efficiently applied to the flexible pipe 4. It is possible to convert to tightening force.

[Fifth Embodiment] FIG. 17 is a front view of an elastic tightening ring 18 used in a fifth embodiment. The elastic tightening ring 18 is formed by integrally arranging the hard elastomers 34 and the soft elastomers 36 alternately in the circumferential direction, and the other configuration may be the same as each of the above embodiments. According to the embodiment using such an elastic tightening ring 18, a relatively hard elastomer 34 is used to lock the convex portion of the flexible tube 4 to secure the retaining action, while a relatively soft elastomer 34 is used. Since the effect of facilitating the expansion and contraction of the elastic tightening ring 18 is obtained by 36, it is easy to achieve both easy insertion of the flexible tube 4 and a retaining effect. This configuration can be applied to any of the embodiments.

It should be noted that the present invention is not limited to only the above-described embodiments, and the features of each embodiment may be appropriately combined, or the configuration may be changed without departing from the spirit of the present invention. Is also possible.

[0044]

As described above, according to the joint for a flexible pipe according to the present invention, the elastic tightening ring is compressed by operating the pressing body, and the flexible pipe is tightened by expanding the inner peripheral surface thereof. Since the flexible tube is hermetically sealed and fixed, there is no need to crush the ridge of the flexible tube when connecting the flexible tube, and no excessive force is required to rotate the pressing body. In addition, since the elastic tightening ring pressed in the axial direction bulges in the inner and outer radial directions, the space between the inner peripheral surface of the joint body and the outer peripheral surface of the flexible pipe is hermetically sealed over a wide range. And sealing can be performed simultaneously. Therefore, it is not necessary to separately seal the distal end of the flexible tube, and the cut surface of the flexible tube may have some irregularities. Therefore, it is possible to improve the gas sealing property and to increase the ease of the connection operation.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a first embodiment of a flexible pipe joint according to the present invention.

FIG. 2 is an enlarged cross-sectional view of the elastic tightening ring of the first embodiment.

FIG. 3 is an enlarged sectional view showing a modification of the elastic tightening ring.

FIG. 4 is an enlarged sectional view showing a modification of the elastic tightening ring.

FIG. 5 is an enlarged sectional view showing a modification of the elastic tightening ring.

FIG. 6 is an enlarged sectional view showing a modification of the elastic tightening ring.

FIG. 7 is an enlarged sectional view showing a modification of the elastic tightening ring.

FIG. 8 is an enlarged sectional view showing a modification of the elastic tightening ring.

FIG. 9 is an enlarged sectional view showing a modification of the elastic tightening ring.

FIG. 10 is an enlarged sectional view showing a modification of the elastic tightening ring.

FIG. 11 is an enlarged sectional view showing a modification of the elastic tightening ring.

FIG. 12 is a partial sectional view of another embodiment of the flexible pipe joint according to the present invention.

FIG. 13 is a partial cross-sectional view of another embodiment of the flexible pipe joint according to the present invention.

FIG. 14 is an enlarged sectional view showing a modification of the elastic tightening ring.

FIG. 15 is an enlarged sectional view showing a modification of the washer.

FIG. 16 is a partial sectional view of another embodiment of the flexible pipe joint according to the present invention.

FIG. 17 is a front view showing a modification of the elastic tightening ring.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Joint main body 1B Tapered surface 2 Pressing nut (pressing body) 4 Flexible tube 6 Protective outer skin 10 Partition wall 12 Female screw part 14 Male screw part 18 Elastic tightening ring 18A Tapered surface 29 Leak detection hole 32 Spacer 50 Washer 52, 56 annular Convex portions 54, 58 Annular concave portions 60, 62, 64, 66, 68, 69 Relatively hard portions

Claims (7)

[Claims] 1. A joint for a flexible pipe attachable to a flexible pipe (4) having irregularities on an outer peripheral surface, the tubular joint body (1) into which the flexible pipe (4) is inserted, and the joint body Placed inside (1),
An elastic tightening ring (18) having a concave portion and / or a convex portion formed on its inner peripheral surface capable of engaging with irregularities on the outer peripheral surface of the flexible pipe (4), and screwed to the joint body (1). And a pressing body (2) for compressing the elastic tightening ring (18) in the axial direction when rotated. The elastic tightening ring (18) is at least partially formed of an elastic body, A flexible pipe joint characterized in that when compressed in the axial direction by the body (2), the inner diameter of the flexible pipe (4) is reduced and the outer circumference of the flexible pipe (4) is airtightly tightened. 2. The joint for a flexible pipe according to claim 1, wherein said elastic body is a thermoplastic elastomer or rubber. 3. A washer (50) made of a material harder than the elastic tightening ring (18) is arranged between the elastic tightening ring (18) and the pressing body (2). The flexible pipe joint according to claim 1, wherein: 4. A relatively hard annular portion (62) is provided at an end of the elastic tightening ring (18) to be brought into contact with the pressing body (2). The flexible pipe joint according to claim 1, wherein the joint is formed integrally with the joint. 5. A relatively hard member (64, 66, 68) wherein at least a part of the projection and / or the recess is provided.
The joint for a flexible pipe according to any one of claims 1 to 4, wherein the joint is formed of: 6. A tapered portion (1A) having a diameter that is relatively reduced from the side of the pressing body (2) to the opposite side is formed on at least a part of the inner peripheral surface of the joint body (1). The flexible pipe joint according to any one of claims 1 to 5, wherein: 7. A gas leak detection hole (29) extending from an outer peripheral surface to an inner peripheral surface of the joint body (1). For flexible pipes.