JP4156218B2 - Pipe joint seal mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pipe joint, and in particular, to a pipe joint seal mechanism for connecting a metal flexible hose or other flexible pipe to a gas appliance or a gas pipe.
[0002]
[Prior art]
Conventionally, a pipe joint sealing mechanism for connecting a pipe and a flexible pipe is generally known. A known pipe joint sealing mechanism is as shown in FIG. As shown in FIG. 1, one end of a flexible tube (2) whose outer peripheral surface is resin-coated is a taper tube expansion portion (21) that expands toward the tip, and the taper tube expansion portion ( A cap nut (4) having a tapered surface (41) coinciding with the outer surface of 21) is screwed. A joint pipe (3) having a tapered surface (31) whose outer periphery coincides with the inner surface of the tapered pipe expanding portion (21) is screwed into the cap nut (4), and the joint pipe (3) is inserted into the joint nut (3). A pipe (11) is screwed and joined to connect a gas appliance or the like.
[0003]
In this case, when the joint pipe (3) and the cap nut (4) are screwed together and tightened, the tapered surface (31) of the joint pipe (3) is pressed against the tapered expanded portion (21) of the flexible pipe (2). Therefore, the sealing property of the pipe connection portion is ensured at the pressure contact surface. In order to further improve the sealing performance, an annular groove is provided in the outer tapered surface (31) of the joint pipe (3), and a seal packing (51) is fitted into the annular groove.
[0004]
[Problems to be solved by the invention]
However, the above conventional one has the following problems.
[0005]
In the case where no seal packing is used, there is a problem in the sealing effect because it is difficult to ensure airtightness with high accuracy.
[0006]
In the case where an annular groove is provided in the tapered surface of the outer surface of the joint pipe (3) and the seal packing (51) is provided on this, the seal packing is only brought into contact with one side (inner surface) of the taper, so that the sealing performance is ensured. hard. Further, since the seal packing is exposed to the outside, it is easily damaged. Since the annular groove is provided on the outer surface of the tapered surface, labor is required for processing and the cost is increased. Since the seal packing is buried in the annular groove by tightening, there is a problem that the sealing performance is poor because the pressing force is small.
[0007]
The present invention has been made in view of such problems, and the object thereof is to connect a joint pipe of a connection pipe and a flexible pipe such as a metal flexible hose and fasten it with a fastening nut. When the joint pipe and the cap nut are screwed and tightened, the sealing performance by the seal packing is performed with high precision and efficiency, and the seal packing can be provided on the cap nut side so that the seal packing is exposed to the outside and damaged. In addition, the sealing performance is improved by further increasing the pressing force of the seal packing, and further reliability is improved.
[0008]
[Means for Solving the Problems]
The technical means of the present invention for solving the above problems is a pipe joint for connecting a pipe and a flexible pipe, wherein the joint pipe of the pipe and a fastening nut for fastening the flexible pipe are screwed and fastened. A taper tube at the tip of the flexible tube is inserted between the tapered surface of the outer surface and the inner surface of the cap nut and fastened together. A U-shaped concave annular groove is formed on the inner surface of the cap nut. A seal packing made of an elastic ring is fitted in the annular groove, and a fitting portion for the seal packing is provided at the extreme end of the tapered surface of the joint pipe. The seal packing is pressed between the parts.
[0009]
According to the above technical means, the taper expanded portion at the tip of the flexible tube is sandwiched between the tapered surface of the outer surface of the joint tube and the inner surface of the cap nut. In addition to ensuring the performance, the seal packing fitted in the annular groove on the inner surface of the cap nut is sealed between the outer surface of the joint pipe and the sealing effect can be doubled.
[0010]
The second technical means of the present invention is that the end of the taper expanded portion of the flexible tube faces the annular groove on the inner surface of the fastening cap nut so as to contact the seal packing.
[0011]
According to such a technical means, the tip end portion of the taper expanded portion comes into contact with the seal packing more strongly by tightening the cap nut, so that the third sealing effect can be expected.
[0012]
Furthermore, the third technical means of the present invention is to provide a pressing step portion of the seal packing at the fitting portion of the joint pipe.
[0013]
According to such technical means, the seal packing is pressed forward by the protruding step portion on the outer surface of the joint pipe by tightening the cap nut, so that the tip of the taper expanded portion and the seal packing are in pressure contact so as to bite more strongly. As a result, it is possible to expect an effect of greatly improving the sealing performance.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
[0015]
【Example】
2 to 4 show the pipe joint sealing mechanism of the present invention, FIG. 2 shows an example of the whole pipe joint, and FIG. 3 shows an enlarged view of the main part thereof. FIG. 4 is an enlarged view of a main part of another example.
[0016]
First, FIG. 2 will be described. The flexible tube 2 made of a metal bellows tube has a resin coating (not shown) whose outer peripheral surface is coated, and one end of the flexible tube 2 expands in a trumpet shape toward the rear (front side in FIG. 2). It becomes the taper pipe expansion part 21 which has.
[0017]
The fastening nut 4 is externally fitted to the flexible tube 2 so as to be rotatable in a state in which the tapered pipe expanding portion 21 is accommodated. On the inner peripheral surface of the cap nut 4, a tapered surface 41 that overlaps with the outer peripheral surface of the tapered pipe expanding portion 21 and a U-shaped concave annular groove 42 are formed in series on the inner peripheral side surface following the tapered surface. The cap nut 4 is engraved with a female screw 43 for screwing the joint tube 3 from the opposite side of the flexible tube 2, and the outer periphery of the cap nut is formed in a hexagonal column surface. A spanner can be engaged.
[0018]
The joint pipe 3 to be screwed into the female screw 43 of the cap nut 4 has a tapered surface 31 tapered on the outer peripheral surface of the tip in the screwing direction, and the taper surface 31 is a taper expansion of the flexible tube 2. It has a shape that overlaps closely with the inner peripheral surface of the portion 21.
[0019]
Further, a male screw 34 to be screwed into the female screw 43 of the cap nut 4 is engraved on the outer periphery of the distal end portion of the joint pipe 3, and the outer periphery of the rear end portion is formed in a hexagonal shape so that the portion is engaged with a spanner. It becomes part 35. Further, a female thread 36 is provided on the inner peripheral surface of the rear end portion of the joint pipe 3, and the pipe 1 is screwed into this.
[0020]
A seal packing 5 made of an elastic ring is fitted in a U-shaped concave annular groove 42 formed on the inner surface of the cap nut 4. The cross-sectional shape of the seal packing 5 is preferably circular as shown in the illustrated example. However, the shape is not limited to a circle, and an oval, an ellipse, or a polygon is not acceptable. The groove width of the annular groove 42 is preferably large enough to fit the seal packing 5. However, the spacer 45 can be used when a gap is generated.
[0021]
The fitting portion 32 of the seal packing 5 is provided at the end of the tapered surface 31 on the outer surface of the joint pipe 3. The fitting portion 32 is fitted to the inner peripheral surface side of the seal packing 5 fitted in the U-shaped annular groove 42 on the inner surface of the cap nut 4, and between the annular groove and the fitting portion by tightening the cap nut. The seal packing is pressed. Accordingly, the fitting portion 32 is preferably an arc-shaped concave groove adapted to the cross-sectional shape of the seal packing as shown in FIGS.
[0022]
Further, as shown in FIG. 4, the fitting portion 32 can include a protruding step portion 33 that presses the rear lower surface portion of the seal packing 5 forward from the rear as the cap nut is tightened. However, such a fitting portion 32 is not limited to the shape described above, and may be a concave groove such as a V shape, or may remain flat in some cases.
[0023]
As described above, the taper expanded portion 21 of the flexible tube 2 is sandwiched between the tapered surface 41 of the inner surface of the cap nut 4 and the tapered surface 31 of the outer surface of the joint tube 3 and is brought into a close contact state between the inner and outer surfaces according to tightening. Further, as shown in FIG. 3, the end portion 22 of the taper tube expanding portion 21 is brought into contact with the U-shaped concave annular groove 42 so as to protrude from the surface of the seal packing 5. More preferably, as shown in FIG. 4, the end portion 22 of the taper expanded portion 21 can be brought into contact with the seal packing so that the end portion 22 deeply penetrates into the seal packing by approaching the end portion 22 to a deeper position.
[0024]
According to the above configuration, in FIG. 3, the contact point of the seal packing 5 is a. b. c. A high sealing effect is obtained at four points d. In FIG. 4, since the pressing point e by the pressing step 33 is added, the a. b. c. A higher sealing effect can be obtained at five contact points obtained by adding e to d.
[0025]
[Action and effect]
The cap nut 4 that is externally fitted to one end of the flexible tube 2 is screwed into the male thread 34 of the joint tube 3 and tightened with a spanner, whereby the taper expanded portion 21 of the flexible tube 2 is connected to the inner and outer tapered surfaces 31. When pinched by 41, sealing performance is ensured only by this portion due to close pressure bonding between the metals.
[0026]
The seal packing 5 fitted inside the U-shaped concave annular groove 42 on the inner surface of the cap nut 4 by the above-mentioned tightening is pressed against both the inner and outer surfaces and sealed at points a, b, and c, and further, the taper expansion portion The end 22 of 21 contacts the surface of the seal packing 5 and is sealed at the contact point d. When the seal packing 5 is pressed and compressed by the pressing step 33 on the side of the joint pipe 3 from the rear as shown in FIG. 4, the seal packing 5 is further sealed at the point e and the seal of the end portion 22 of the taper expanded portion 21. The encroaching into the packing is strong, and higher sealing performance is secured.
[Brief description of the drawings]
FIG. 1 is a longitudinal side view of an entire conventional pipe joint sealing mechanism.
FIG. 2 is a side view of the entire pipe joint sealing mechanism showing an embodiment of the present invention, and the left half is shown in cross section.
FIG. 3 is an enlarged cross-sectional view showing a main part of the seal mechanism of the present invention.
FIG. 4 is an enlarged cross-sectional view of a main part of a seal mechanism showing another embodiment of the present invention.
[Explanation of symbols]
1 Piping 2 Flexible tube (Metal flexible hose)
3 Joint Pipe 4 Fastening Cap Nut 5 Seal Packing 21 Taper Expanded Portion 22 End 31.41 Taper Surface 32 Fitting 33 Pushing Step 42 Annular Groove

Claims (3)

A pipe joint that connects the pipe (1) and the flexible pipe (2), and the joint pipe (3) of the pipe (1) and the fastening nut (4) of the flexible pipe (2) are screwed together. The taper expanded portion (21) at the tip of the flexible tube (2) is inserted between the tapered surface (31) of the outer surface of the joint pipe (3) and the tapered surface (41) of the inner surface of the cap nut (4). In addition, a U-shaped concave annular groove (42) is formed on the inner surface of the cap nut (4), and a seal packing (5) made of an elastic ring is fitted into the annular groove (42). The fitting portion (32) of the seal packing (5) is provided at the end of the tapered surface (31) of the outer surface of the joint pipe (3), and the annular groove (42) is tightened by tightening the cap nut (3). A pipe joint sealing mechanism comprising a seal packing pressed between the fitting portions (32). The end (22) of the taper expanded portion (21) of the flexible tube (2) is brought into contact with the seal packing (5) in the annular groove (42) on the inner surface of the fastening nut (4). The pipe joint sealing mechanism according to claim 1. The pipe joint seal mechanism according to claim 1, wherein a pressing protrusion (33) of the seal packing (5) is provided on the fitting part (32) of the joint pipe (3).

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