JP2012241744A - Joint for flexible tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the assembling labor, the material cost and the manufacturing cost by improving a seal member.SOLUTION: This joint for a flexible tube includes a cylindrical body 11 and a stopper ring 61 integrally joined on the same axis. A corrugated tube 2 exposed in crest parts 4 and trough parts 5 by eliminating a tip part of a cover body 3 in a flexible tube 1 is inserted into the cylindrical body 11 through the stopper ring 61 to join the corrugated tube 2 with the cylindrical body 11. An annular seal member 31 constituted of a center layer 32 and an outer wrapping layer 33 is interposed between the inner surface of the cylindrical body 11 and the corrugated tube 2. The seal member 31 is structured by including a rubber material and a fire resistant foaming material in the center layer 32 and including a rubber material in the outer wrapping layer 33.

Description

  The present invention relates to a joint for a flexible tube, and more particularly to a joint in which a seal member is improved in a joint for connecting a flexible tube composed of a corrugate pipe used for gas piping or the like.

For example, in a gas pipe, there are joints that connect a flexible tube made of a corrugate pipe, for example, disclosed in Patent Documents 1 to 3.
This consists of a cylindrical body on one end integrally joined on the same axis, and a retaining ring attached to the other end of the cylindrical body, and a covering is provided on a corrugate tube having a peak and a valley. When connecting the externally fitted flexible tube, the flexible tube can be joined to the tubular body by inserting the distal end of the corrugate tube with the covering of the distal end portion removed from the retaining ring into the tubular body. It is a thing.

  This cylindrical body is internally provided with an airtight seal material in order to prevent gas leakage from the gap with the corrugate tube. In addition, a fireproof sealing material is also provided to prevent leakage of gas when the hermetic sealing material is burned down by exposure to high temperatures due to a fire.

JP 2007-211838 A JP 2008-240771 A Japanese Patent No. 4409199

  However, two types of seal members for airtightness and fireproof are necessary, a processing step for forming the respective accommodating portions of the seal member and the fireproof member in the cylindrical body, and an assembly step for incorporating the two types of seal members, respectively. There was a problem that labor and cost increased.

  An object of this invention is to provide the coupling for flexible tubes which can reduce an assembly effort, material cost, and manufacturing cost by the improvement of a sealing member.

The invention described in claim 1
It has a cylindrical main body integrally joined on the same axis, and a retaining ring attached to the cylindrical main body, and removes the tip of the covering in the flexible tube to expose the peaks and valleys. By inserting the corrugated pipe into the inside of the cylindrical body from the retaining ring, a flexible tube joint capable of joining the corgate pipe to the cylindrical body,
Between the inner surface of the cylindrical main body and the corrugate tube, an annular sealing member consisting of a center layer and an outer envelope layer is interposed,
In the sealing member, the central layer includes a rubber material and a fireproof foam material, and the outer envelope layer includes a rubber material.

The invention according to claim 2 is the configuration according to claim 1,
The center layer has a volume expansion coefficient of 4 to 8 times when exposed to high temperature,
When the cylindrical body is exposed to a high temperature and the outer envelope layer of the sealing member disappears, the central layer expands to a volume that includes at least the central layer of the outer envelope layer or a radial thickness of the outer envelope layer, The outer peripheral portion of the corrugate tube is formed so as to fill a gap between the cylindrical main body.

The invention according to claim 3 is the configuration according to claim 1 or 2,
The rubber material of the center layer and the rubber material of the outer envelope layer are the same rubber material,
The rubber material is nitrile rubber.

According to a fourth aspect of the present invention, in the configuration of the first or second aspect,
The fireproof foam is thermally expanded graphite,
The content of thermally expanded graphite in the center layer is 20% by weight to 40% by weight.

  According to the first aspect of the present invention, in the joint comprising the tubular main body and the retaining ring, the corrugate tube of the flexible tube from which the distal end portion of the covering body has been deleted is inserted and connected to the tubular body from the retaining ring. The seal member interposed between the inner surface of the cylindrical main body and the corrugate pipe is composed of a center layer made of a fireproof foam material and a rubber material, and an outer envelope layer made of a rubber material covering the center layer. The outer envelope layer provides excellent sealing performance under normal conditions, and when the outer envelope layer is burned down by a fire, the center layer expands and can seal the tubular body and corrugate tube well, preventing gas leakage can do. Therefore, the two types of sealing members for airtightness and fireproof which were necessary in the past are not required, the housing structure of the sealing member in the cylindrical body can be simplified, and the assembly of the flexible tube joint can be improved. Thus, the material cost and the manufacturing cost can be reduced.

  According to the invention of claim 2, when the cylindrical main body is exposed to a high temperature and the outer envelope layer of the sealing member disappears, the center layer is at least the volume of the outer envelope layer or the radial thickness of the outer envelope layer. As described above, the gap between the inside of the cylindrical main body can be reliably sealed at the outer peripheral portion of the corgate pipe.

According to the invention described in claim 3, since the nitrile rubber is a material excellent in oil resistance, water resistance and gas permeation resistance, more excellent sealing performance can be exhibited.
According to the fourth aspect of the present invention, since the fire-resistant foam material is thermally expanded graphite, and the content of thermally expanded graphite in the center layer is 20 wt% to 40 wt%, the flexibility of the center layer due to the rubber material is impaired. Even when exposed to high temperatures in the event of a fire, high sealing performance can be exhibited.

Example 1 of the joint for flexible tubes which concerns on this invention is shown, and it is a half longitudinal cross-sectional view of the joining state of a flexible tube. It is a partially cutaway perspective view showing a seal member. It is a fragmentary longitudinal cross-section when a load in the pulling direction is applied to the flexible tube. It is a fragmentary longitudinal cross-section when the joint for flexible tubes is exposed to high temperature. It is a partial expanded longitudinal cross-sectional view of a retaining ring. It is a partially cutaway perspective view of the flexible tube joint. Example 2 of the joint for flexible tubes which concerns on this invention is shown, and it is a half longitudinal cross-sectional view before flexible tube insertion. It is a half longitudinal cross-sectional view of a flexible tube joined state. It is a semi-longitudinal sectional view when the joint for flexible tubes is exposed to high temperature. Example 3 of the joint for flexible tubes which concerns on this invention is shown, and it is a longitudinal cross-sectional view before flexible tube insertion. It is a longitudinal cross-sectional view of a flexible tube joining state. It is a longitudinal cross-sectional view when the joint for flexible tubes is exposed to high temperature.

[Example 1]
Hereinafter, a first embodiment of a joint for a flexible tube in which a seal member according to the present invention is installed will be described with reference to FIGS.

  In FIG. 1, reference numeral 1 denotes a flexible tube, which is composed of a thin stainless corrugate tube 2 and a resin tube-like covering 3 that covers the outer periphery of the corrugate tube 2. The corrugate tube 2 has crests 4 and troughs 5 formed alternately. The flexible tube 1 is joined to the joint 10 in a state where the covering 3 is removed from a predetermined number of peak portions 4 on the distal end side of the corgate tube 2.

(Cylindrical body)
The joint 10 includes a cylindrical main body 11 and a retaining ring 61 that is integrally mounted on the same axis O of the cylindrical main body 11. The cylindrical main body 11 is formed of a metal such as brass, and an external thread portion 12 is formed on one end thereof, and can be connected to a connected body such as a gas pipe or a gas appliance. A tool hook portion 13 is formed on the other end side of the external screw portion 12 and is used for screwing the external screw portion 12. On the inner circumference on the other end side of the cylindrical main body 11, an inner screw portion 15, an inlet side inner circumference surface 16, and a rear side inner circumference surface 21 are formed in this order from the other end side to the one end side. A back end surface 19 is formed at an end portion of the side inner peripheral surface 21. Further, a cylindrical projection 20 for guiding the corrugate tube 2 is formed on the inner peripheral portion of the rear end surface 19 so as to protrude to the other end side. A housing portion (gap) 22 for housing the distal end portion of the corrugate tube 2 and a sealing material to be described later is formed between the inner circumferential surface 21 on the back side and the cylindrical projection 20. A tapered surface 20 a that guides the insertion of the corrugate tube 2 is formed on the outer peripheral surface of the other end of the cylindrical protrusion 20. A tip portion of the corrugate tube 2 is disposed on the inner peripheral portion of the accommodating portion 22.

(Stop ring)
The retaining ring 61 is formed in a cylindrical shape from a composite of a metal such as brass and a transparent resin. That is, it is made of a metallic base end cylindrical portion 63 joined to the cylindrical main body 11 and a transparent resin made to be fitted and fixed to the other end side of the base end cylindrical portion 63 so that the flexible tube 1 can be seen from the outside. It is comprised with the front-end | tip cylinder part 64. FIG.

  As shown in FIG. 4, an outer screw portion 12 that can be screwed into the inner screw portion 15 of the cylindrical main body 11 is formed in the proximal end cylindrical portion 63. In addition, a large-diameter portion 65 on one end side and a small-diameter portion 66 formed on the other end side from the large-diameter portion 65 through a stepped portion are provided on the outer peripheral portion of the proximal end cylindrical portion 63. An annular locking groove 67 having a predetermined width is formed from the step portion. An insertion hole 84 that guides the insertion of the corrugate tube 2 is formed in the proximal end cylindrical portion 63, and an inner peripheral tapered portion 68 that gradually increases in diameter toward one end is formed in the inner peripheral portion of the outer screw portion 12. ing.

  The distal end cylindrical portion 64 includes an outer cylindrical portion 70 disposed on the outer peripheral side, and a restriction cylindrical portion 72 that is fitted in the hole 71 of the outer cylindrical portion 70 and disposed at a predetermined position. Further, the outer peripheral surface 73 of the outer cylinder part 70 is formed to have a larger diameter than the outer screw part 12, and a hole part 71 is formed inside. Further, on the other end side of the outer cylinder portion 70, a connecting cylinder portion 75 that is externally fitted to the small diameter portion 66 of the proximal end cylinder portion 63 and bonded and sealed, and an inner peripheral surface on one end side of the connecting cylinder portion 75. And an annular claw portion 76 that protrudes toward the center and fits into the locking groove 67 is provided. Further, an annular protrusion 77 having a substantially triangular cross section is provided on the inner peripheral portion of the hole 71 corresponding to the insertion port 30.

  The restriction cylinder portion 72 is formed with a curved surface 78 for guiding the flexible tube 1 to the inner peripheral corner portion on the other end side and a large-diameter hole portion 79 into which the covering body 3 of the flexible tube 1 is inserted. In addition, a small-diameter hole 80 is formed at one end of the large-diameter hole 79 so as to restrict insertion of the cover 3 and allow insertion of the corrugate tube 2 via the restriction step 81 to constitute a restriction part. Yes.

  An accommodation groove 83 for a ring-shaped packing 82 is formed between the annular protrusion 77 and the regulation cylinder part 72 in the hole 71 of the outer cylinder part 70. This packing 82 has a T-shaped cross section in which a seal piece protrudes along the circumferential direction on the inner peripheral side, and seals the gap between the outer peripheral surface of the cover 3 and the retaining ring 61 to prevent intrusion of water or the like.

  In the joint 10 in this state, the tip of the corrugate tube 2 is cut at the valley portion 5 and the covering 3 is removed from the tip of the corgate tube 2 on the base end side by a certain distance (predetermined number of peaks). The flexible tube 1 is inserted into the cylindrical main body 11 through the small diameter hole 80 from the insertion port 30 of the retaining ring 61. Then, the crest 4 at the tip of the corrugate tube 2 pushes and expands the protrusion 39 of the retainer 38, passes through the position of this protrusion 39, and is press-fitted into the inner periphery of the standard seal material 52. Is pushed to a position close to the fireproof sealing material 51 and accommodated on the inner peripheral side of the accommodating portion 22. At this time, since the outer cylinder part 70 and the regulation cylinder part 72 are formed of a transparent resin, the tip of the covering 3 can be visually observed, and the flexible tube 1 is fixed distance from the tip of the corrugate tube 2. Since the cover 3 is deleted in step S3, when it is visually confirmed that the tip of the cover 3 is in contact with or close to the regulation step portion 81, the tip of the corrugate tube 2 is close to the fireproof sealing material 51. It will be press-fitted to the position to do. Therefore, by confirming the position of the tip of the covering 3 through the outer cylinder part 70 and the regulation cylinder part 72 by visual observation, it is accurately confirmed that the flexible tube 1 and the joint 10 are normally joined. Can do.

(Retainer)
A space 37 surrounded by the inner peripheral tapered portion 68 of the retaining ring 61, the inlet-side inner peripheral surface 16 of the cylindrical main body 11 and the end surface of the seal member 31 is formed, and an annular retainer serving as a retaining member is formed in the space 37. 38 is arranged.

  The retainer 38 is formed of a metal material such as brass, and a radially inward protruding portion 39 is formed on one end side thereof, that is, on the back side of the cylindrical main body 11. The protrusion 39 can fit into the valley 5 of the corgate pipe 2 when the corgate pipe 2 is inserted into the joint 10. Further, a tapered surface 40 that can contact the inner peripheral tapered portion 68 of the retaining ring 61 is formed on the outer periphery of the retainer 38. Furthermore, the retainer 38 is formed with notches in the axial center O direction from one end side having the protrusion 39 toward the other end side at a plurality of positions in the circumferential direction. Thus, the ridge 4 of the corgate tube 2 can be passed. An annular groove 41 having a rectangular cross section is formed on the outer periphery on one end side of the retainer 38, and the protrusion 39 of the retainer 38 changes from the expanded diameter state to the reduced diameter state of FIG. A ring spring 42 for applying a force is fitted.

  In FIG. 1, reference numeral 43 denotes a packing 43 provided between the end surface of the cylindrical main body 11 and the stepped portion of the proximal end cylindrical portion 63, which allows gas to pass from the inside of the joint 10 to the outside. The passage of water from the outside to the inside is not allowed.

(Seal member)
A cylindrical seal member 31 according to the present invention is disposed in the accommodating portion 22 of the cylindrical main body 11 so as to be fitted around the corrugate tube 3. As shown in FIG. 2, the seal member 31 includes a center layer 32 and an outer envelope layer 33 covering the periphery of the center layer 32, and the center layer 32 includes a rubber material and a fireproof foam material. The outer envelope layer 33 is made of an airtight sealing material containing a rubber material. When the joint 10 is exposed to a high temperature and the outer envelope layer 33 of the sealing member 31 disappears, the central layer 32 exceeds at least the volume of the outer envelope layer 33 and exceeds the radial thickness of the outer envelope layer 33, or The expansion rate of the volume of the central layer 32 by heating so that the outer envelope layer 33 expands beyond the volume including the central layer 32 and fills the gap between the outer peripheral portion of the corrugate tube 2 and the cylindrical main body 11 to maintain the sealing performance. The volume ratio between the outer envelope layer 33 and the center layer 32 is set.

  The rubber material of the center layer 32 and the rubber material of the outer envelope layer 33 are the same rubber material, and nitrile rubber (NBR) excellent in oil resistance, water resistance and gas permeability is suitable, but is not limited to this. It is not something. Further, as the refractory foam material, thermally expanded graphite having high thermal expansion performance is suitable, but is not limited thereto.

  The content ratio of the refractory foam to the rubber material of the center layer 32 is preferably 20% by weight to 40% by weight. This is because if the content ratio of the refractory foaming material is less than 20%, the volume expansion rate at the time of fire is small and the sealing performance at the time of fire may be impaired, and if it exceeds 40% by weight, the rubber material This is because the airtight sealability during normal times may be impaired by impairing the flexibility of the center layer 32 due to the above. If the content ratio of the refractory foam to the rubber material is 20% by weight to 40% by weight, the normal sealing performance can be exhibited without impairing the flexibility of the center layer 32 by the rubber material, and even in the event of a fire. High sealing performance can be ensured. Furthermore, when the content ratio of the refractory foam to the rubber material of the center layer 32 is 25 wt% to 35 wt%, it is further optimized.

  Moreover, the volume expansion coefficient of the center layer 32 by heating is set to 4 to 8 times, for example. This is because if the volume expansion coefficient of the center layer 32 is less than 4 times, the volume of the center layer 32 is large in order to have the same volume as the seal member 31 (the outer envelope layer 33) when exposed to a high temperature in the event of a fire. This is because the thickness of the outer envelope layer 33 becomes thin and the sealing performance during normal times may be impaired. Further, if the volume expansion coefficient of the center layer 32 exceeds 8 times, the rubber elasticity becomes small and becomes brittle when the center layer 32 is molded, and there is a problem that the shape cannot be easily held and cannot be wrapped by the outer envelope layer 33. It is.

(Bonding of flexible tube and joint)
When the flexible tube 1 is joined to the joint 10, the covering 3 is removed within a certain range at the tip of the flexible tube 1, and the corgate pipe 2 is exposed, and this is inserted into the joint 10 from the insertion port 30. To do. At this time, the corrugate tube 2 is inserted into the inner periphery of the seal member 31 after the distal end portion of the corrugate tube 2 pushes the retainer 38 and passes through the position of the retainer 38. The distal end portion of the corrugate pipe 2 reaches the back end surface 19 through the inner periphery of the seal member 31. The outer periphery of the appropriate number of peaks 4 is in close contact with at least the inner periphery of the seal member 31. Further, the protrusion 39 of the retainer 38 fits into the trough 5 at a position spaced from the tip of the corgate pipe 2. Furthermore, the front end portion of the cover 3 in the flexible tube 1 fits inside the retaining ring 61. The packing 82 seals the outer periphery of the covering 3 to prevent water and the like from entering the joint 10.

  Sealing between the joint 10 and the flexible tube 1 is normally performed by the outer envelope layer 33 of the seal member 31. When the joint 10 is exposed to a high temperature due to the occurrence of a fire or the like, the outer envelope layer 33 is burned away, but the center layer 32 exhibits a sealing function instead. That is, the center layer 32 is a fireproof sealing material including a rubber material and a fireproof foaming material. When the volume of the fireproof foaming material is increased when exposed to a high temperature, voids generated due to the burnout of the outer envelope layer 33 or the like. Fills in and thus performs the required sealing function.

  Further, when the pulling-out force from the joint 10 acts on the flexible tube 1, the taper surface 40 on the outer periphery of the retainer 38 in which the protrusion 39 is fitted in one valley portion 5 of the corrugate tube 2 is formed inside the retaining ring 61. The retainer 38 receives a reaction force radially inward from the retaining ring 61 when it hits the circumferential taper portion 68. As a result, the hooked state of the retainer 38 and the corrugate tube 2 is ensured, thereby preventing the flexible tube 1 from coming out of the joint 10.

  Thus, gas pipe can be constituted by joining joint 10 and flexible tube 1, and it can use for piping between a gas pipe and a gas appliance, for example using this gas pipe.

(Effect of Example 1)
According to the first embodiment, the corrugate tube 2 of the flexible tube 1 having the cylindrical main body 11 and the retaining ring 61 and having the distal end portion of the covering 3 removed is inserted into the cylindrical main body 11 from the retaining ring 61. In the joint thus connected, a seal member 31 interposed between the inner peripheral surface 21 of the cylindrical main body 11 and the corrugate tube 2 is provided with a center layer 32 made of a fireproof foam material and a rubber material, and the center layer. Since the outer envelope layer 33 made of a rubber material covering the periphery of the outer peripheral layer 32 is provided, the outer envelope layer 33 can exhibit an excellent sealing property in a normal state, and when exposed to a high temperature due to a fire or the like, the outer envelope layer 33 of the seal member 31. When the gas is burned out, the center layer 32 expands, and the gap between the tubular body 11 and the corrugate tube 2 can be well sealed, and gas leakage can be prevented. Therefore, the two sealing members for airtightness and fireproof which were conventionally required are unnecessary, the housing structure of the sealing member in the cylindrical main body 11 can be simplified, and the assemblability of the flexible tube joint can be improved. Thus, the material cost and the manufacturing cost can be reduced.

  Further, when the outer envelope layer 33 is burned out, the center layer 32 is at least the volume of the outer envelope layer 33 or at least the radial thickness of the outer envelope layer 33 cross section. The accommodating part 22 between the surface 21 and the corrugate pipe 2 can be reliably sealed.

  Furthermore, by making the rubber material nitrile rubber excellent in oil resistance, water resistance, and gas permeation resistance, more excellent sealing performance can be exhibited. Furthermore, since the fire-resistant foam material is thermally expanded graphite, and the content of thermally expanded graphite in the center layer 32 is 20% by weight to 40% by weight, a fire is generated without impairing the flexibility of the center layer 32 made of a rubber material. High sealing performance can be exhibited at times.

[Example 2]
Second Embodiment A flexible tube joint according to a second embodiment of the present invention will be described with reference to FIGS.

  7 shows a state before the flexible tube 1 is inserted, FIG. 8 shows a state in which the flexible tube 1 is inserted (the phantom line is a state in which a load in the pulling direction is applied to the flexible tube 1), and FIG. 9 shows a state in which the flexible tube 1 is exposed to high temperature. Respectively.

  7-9, 101 is a cylindrical main body which comprises the coupling 100, the external thread part 102 is formed in the one end side, and the retaining ring 110 is mounted | worn on the same axial center at the other end side. A movable cylinder 103 for restricting the end of the corrugate tube 2 is inserted into the inner end of the hole of the cylindrical main body 101, and a holding means 104 including a coil spring 104 a is fitted around the outer periphery of the movable cylinder 103. Has been.

  A cylindrical seal member 131 according to the present invention is disposed on the other end side of the holding means 104 via an annular guide member 105. The seal member 131 includes a center layer 132 and an outer envelope layer 133 that covers the periphery of the center layer 132. The center layer 132 includes a fireproof sealant that includes a rubber material and a fireproof foam material, and the outer envelope layer 133 is a rubber. It consists of an airtight sealing material containing the material, and is composed of the same material as in the first embodiment.

  A retainer 106 is disposed on the other end side of the seal member 131, and when a load in the pulling direction is applied to the flexible tube 1, the claw portions are brought into contact with the tapered surface of the retaining ring 110 and the claw portions are engaged with the valley portions of the corrugate tube 2. The flexible tube 1 is prevented from coming off. 107 is a stopper ring for preventing the retaining ring 110 from coming off, 108 is a permselective member disposed in the vent hole of the retaining ring 110, 109 is a disassembly ring, and 111 is a watertight packing.

  In the above configuration, when the joint 100 is exposed to a high temperature due to a fire or the like, the outer envelope layer 133 is burned out, but the center layer 132 exhibits a sealing function instead. That is, the center layer 132 is a fireproof sealing material including a rubber material and a fireproof foam material. When exposed to a high temperature, the volume of the fireproof foam material increases and expands in a range of 4 to 8 times the original volume. In addition, the volume of the seal member 131 is increased or more, and the guide member 105 is pushed out to the other end side by the coil spring 104a of the holding means 104, so that the center layer 132 is filled between the guide member 105 and the retainer 106. The gap between the tubular main body 101 and the corrugate tube 5 caused by the burnout of the outer envelope layer 33 can be filled and a required sealing function can be exhibited.

[Example 3]
Embodiment 3 of the joint for flexible tube according to the present invention will be described with reference to FIGS.

10 shows a state before insertion of the flexible tube 1, FIG. 11 shows an insertion state of the flexible tube 1, and FIG. 12 shows a state exposed to high temperature.
10 to 12, reference numeral 201 denotes a cylindrical main body of the joint 200 having a male thread portion (not shown) formed on one end side, and a retaining ring 210 is mounted on the same axis on the other end side of the cylindrical main body 201. Has been.

  A cylindrical seal member 231 for guiding the corrugate tube 2 is fitted in the cylindrical main body 200, and the seal member 231 includes a center layer 232 and an outer envelope layer 233 that covers the periphery of the center layer 232. The center layer 232 is made of a fireproof sealing material containing a rubber material and a fireproof foaming material, and the outer envelope layer 233 is made of an airtight sealing material containing a rubber material, and is made of the same material as in the first and second embodiments. Composed.

  The outer envelope layer 233 of the seal member 231 has a pipe end receiving part 202 and a seal action part 203 fitted into a trough when the corrugate pipe 2 is inserted at the middle part from the back end to the other end. As shown in FIG. 12, the sealing action portion 203 having a circular cross section is provided at the other end portion, and when the corrugate tube 2 is loaded in the pulling direction, the claw portion is engaged with the valley portion to prevent it from coming off. Metal claws (a kind of retainer) 204 are provided respectively. The center layer 232 is included in the front portion of the metal claw 204 from the sealing action portion 203.

  The retaining ring 210 is provided with an abutting portion 205 that restricts insertion of the end portion of the cover 3 on the inner peripheral portion, and a snap ring 206 that prevents the retaining ring 210 from coming off from the cylindrical main body 201 is externally fitted. ing. 207 is a waterproof packing, and 208 is a malfunction prevention ring.

  When the corrugate tube 2 from which the covering 3 has been deleted within a predetermined range is inserted into the cylindrical main body 201 through the retaining ring 210, the seal member 231 disposed on the other end side is on the back side (one end side). The seal action portion 203 is fitted into the trough portion of the corrugate tube 2 and airtight sealing is performed. The metal claw 204 is engaged with the valley portion of the corrugate tube 2 and is prevented from coming off.

  In the above configuration, when the joint 200 is exposed to a high temperature due to a fire or the like, the outer envelope layer 233 of the seal member 231 is burned out, but instead, the center layer 232 exhibits a sealing function. That is, the center layer 232 is a fireproof sealing material including a rubber material and a fireproof foam material, and the volume of the fireproof foam material is increased when exposed to a high temperature. It expands in the range of 4 to 8 times, and exhibits the required sealing function by filling the gap at the other end in the cylindrical main body 201 with the outer periphery of the corrugate tube 2 caused by the burning of the outer envelope layer 233 or the like. Can do.

O shaft center 1 flexible tube 2 corrugated tube 3 covering 10 joint 11 tubular body 31 sealing member 32 center layer 33 outer envelope layer 38 retainer 61 retaining ring 63 proximal end tubular portion 64 distal end tubular portion 82 packing 100 joint 101 tubular body 104 Holding means 104a Coil spring 105 Guide member 106 Retainer 110 Retaining ring 131 Sealing member 132 Central layer 133 Outer layer 200 Joint 201 Tubular body 202 Pipe end receiving portion 203 Sealing action portion 204 Metal claw 206 Snap ring 210 Retaining ring 231 Sealing member 232 Center layer 233 Outer layer

Claims (4)

It has a cylindrical main body integrally joined on the same axis, and a retaining ring attached to the cylindrical main body, and removes the tip of the covering in the flexible tube to expose the peaks and valleys. By inserting the corrugated pipe into the inside of the cylindrical body from the retaining ring, a flexible tube joint capable of joining the corgate pipe to the cylindrical body,
Between the inner surface of the cylindrical main body and the corrugate tube, an annular sealing member consisting of a central layer and an outer peripheral layer covering the outer peripheral portion of the central layer is interposed,
A flexible tube joint, wherein the seal member is configured such that a center layer includes a rubber material and a fireproof foam material, and an outer envelope layer includes a rubber material. The center layer has a volume expansion coefficient of 4 to 8 times when exposed to high temperature,
When the cylindrical body is exposed to a high temperature and the outer envelope layer of the sealing member disappears, the central layer expands to a volume that includes at least the central layer of the outer envelope layer or a radial thickness of the outer envelope layer, The joint for flexible tubes according to claim 1, wherein the outer periphery of the corrugate tube is formed so as to fill a gap between the cylindrical main body and the tubular body. The rubber material of the center layer and the rubber material of the outer envelope layer are the same rubber material,
The flexible rubber joint according to claim 1 or 2, wherein the rubber material is nitrile rubber. The fireproof foam is thermally expanded graphite,
The flexible tube joint according to any one of claims 1 to 3, wherein the content of thermally expanded graphite in the center layer is 20 wt% to 40 wt%.

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