JP2015007445A - Pipe joint structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipe joint structure capable of rotating a cap nut with small rotation torque when connecting a pipe.SOLUTION: A pipe joint structure including a cup nut 2, and a pipe joint body 5 having a protrusion cylinder part 4 with a male screw 3 to which the cup nut 2 is externally fitted includes a plurality of claw parts 7 protrudingly provided on an end surface 6 of the protrusion cylinder part 4. A pipe insertion hole part 8 of the protrusion cylinder part 4 is formed to be a tapered hole 9 of which diameter is slightly enlarged to an end direction, and by screwing and advancing the cup nut 2 toward the male screw 3, transition to a claw biting state is achieved while an end part 10 of the claw part 7 is pressure-contacted to a pipe outer peripheral surface 11 and a pipe end 12 is pushed and moved to an inner side of the joint body 5, and an end close contact state in which a pipe foremost end 13 is pressure-contacted to an inner peripheral surface 20 of the tapered hole 9 is achieved.

Description

  The present invention relates to a pipe joint structure.

  Conventionally, a tubular retainer with a plurality of small pipe retaining discs revolving (rotating) around the pipe axis, allowing the pipe retaining small disc to rotate and bite into the pipe to prevent it Is known (see, for example, Patent Document 1).

  However, when connecting pipes, there is a large resistance to biting when the small disk for pipe removal bites into the pipe outer peripheral surface while forming a spiral biting trace on the outer peripheral surface of the pipe, and the cylindrical retainer There was a drawback that the rotational torque for rotation was large. Furthermore, there is also a drawback that it is necessary to rotate the retainer a number of times while recessing (forming) the spiral bite mark with a large rotational torque.

  Further, when used for hot water supply or water supply, it is necessary to use an expensive seal having corrosion resistance to prevent corrosion due to chlorine in the water. In addition, there are disadvantages that the number of parts is large, and it takes time and effort to manufacture and assemble.

Japanese Patent No. 312385

  The problem to be solved is that when connecting pipes, an operation of applying a large rotational torque over many revolutions is required, and the work efficiency is low. Moreover, it is necessary to use an expensive corrosion-resistant seal. That is, a seal made of a material such as a normal nitrile rubber cannot be used substantially, resulting in high cost. In addition, the number of parts is large. In addition, it takes time and effort to manufacture and assemble.

  Therefore, the pipe joint structure according to the present invention is a pipe joint structure including a cap nut and a joint main body having a projecting tube portion with a male screw to which the cap nut is externally fitted. A plurality of claws are projected from the front end surface of the pipe, and the pipe insertion hole of the protruding cylinder is formed into a tapered hole whose diameter increases in the front end direction, and the cap nut is screwed onto the male screw. By moving forward, the tip of the claw is brought into pressure contact with the outer peripheral surface of the pipe while the tip of the pipe is pushed and moved to the back of the joint body, and the claw is bitten, and the tip of the pipe is moved to the inner periphery of the tapered hole. The tip is in close contact with the surface.

  In addition, the claw portion is connected to the outer peripheral edge portion of the distal end surface of the protruding cylindrical portion, the thicker portion thicker than the thinner base portion, and the distal end of the thicker portion. In the state in which the cap nut is not screwed, the thick portion is inclined so as to incline radially inward as it extends in the distal direction, and the cap nut is screwed. Therefore, the thick nut is pressed by the cap nut in the axial inward direction and bent around the thin base so as to approach the shape orthogonal to the axial center, and is configured to shift to the nail biting state. is there.

  According to the pipe joint structure of the present invention, when connecting pipes, the cap nut can be rotated with a small rotational torque. And it is sufficient to rotate the cap nut about 1 to 3 times. In addition, it exhibits sufficient pull-out force and withstands pipe pull-out force with a water hammer. In addition, since the life of O-rings made of ordinary materials such as nitrile rubber can be extended, it is possible to use such O-rings (no need for corrosion-resistant seals) and manufacture at low cost. Can do. In addition, the number of parts is reduced, and manufacturing and assembly can be easily performed, and manufacturing can be performed at low cost.

It is a section side view showing the cap nut unscrewed state of a 1st embodiment of the present invention. It is a cross-sectional side view which shows a nail biting state. It is a principal part front view which shows a coupling main body. 3A is a cross-sectional view taken along the line A-O-A in FIG. 3, and FIG. 3B is a cross-sectional view taken along the line B-O-B in FIG. 3. It is a principal part expanded sectional view. It is a principal part expanded sectional view of FIG. It is a principal part expanded sectional view of FIG. It is a perspective view explaining the scar of a pipe in the present invention. It is CC sectional enlarged view of FIG. It is a perspective view explaining the scar of the pipe in a comparative example. FIG. 11 is a DD cross-sectional enlarged view of FIG. 10. It is principal part sectional drawing which shows 2nd Embodiment. It is a principal part cross-section side view which shows the cap nut unscrewed state of 3rd Embodiment. It is a principal part cross-sectional side view which shows a nail biting state. It is a principal part cross-sectional side view which shows the cap nut unscrewed state of 4th Embodiment. It is a principal part cross-sectional side view which shows a nail biting state.

Hereinafter, the present invention will be described in detail based on the illustrated embodiment.
1 and 2 show a first embodiment of the present invention. This pipe joint structure is a pipe joint structure for connecting metal pipes 1 such as stainless steel pipes and steel pipes, and is used, for example, for piping for water supply and hot water supply. A cap body 2 having a cap nut 2 and a projecting cylindrical portion 4 with a male screw 3 to which the cap nut 2 is fitted is provided. The joint body 5 is made of stainless steel, for example, and can be manufactured by the lost wax method, cutting, or the like.

  As shown in FIGS. 3 and 4 (and FIGS. 1 and 2), a plurality of (five in the illustrated example) claw portions 7 project from the distal end surface 6 of the projecting cylindrical portion 4. (The claw part 7 is formed integrally with the protruding cylinder part 4.) It is preferable in terms of strength that the claw parts 7 are arranged at equal intervals in the circumferential direction. A pipe insertion hole 8 of the protruding cylinder 4 is formed in a tapered hole 9 having a diameter slightly increased in the distal direction. The inner peripheral surface 20 of the tapered hole 9 is inclined at an angle θ (see FIG. 4A) with respect to a direction parallel to the axis L in a plane including the axis L. Set the angle θ to less than 1 °. Since the angle θ is less than 1 °, when the pipe 1 is first brought into contact with the inner peripheral surface 20 of the tapered hole 9 and then the cap nut 2 is screwed into the male screw 3, the pipe 1 smoothly moves to the back of the joint body 5. It is pushed. When the angle θ is 1 ° or more, when the pipe 1 is first brought into contact with the inner peripheral surface 20 of the tapered hole 9 and then the cap nut 2 is screwed into the male screw 3, the resistance increases and the cap nut 2 is reduced. Cannot be rotated with rotational torque. Further, the pipe 1 is not pushed into the depth of the joint body 5, and there is a possibility that the trace of biting into the pipe 1 of the claw portion 7 becomes large.

  As shown in the enlarged cross-sectional view of FIG. 5, the claw portion 7 is connected to the outer peripheral edge 15 of the distal end surface 6 of the projecting cylinder portion 4, and the thick portion thicker than the thin base portion 16. 17 and a small biting portion 19 for biting provided continuously to the tip 18 of the thick portion 17 are integrally provided.

  As shown in FIGS. 6 and 7, a friction reducing member 21 for reducing the rotational torque of the cap nut 2 is provided. The friction reducing member 21 includes a cylindrical portion 22 and an inner flange portion 23 in the direction orthogonal to the axis. An O-ring 24 and a pressing ring 25 that presses the O-ring 24 with the deformation of the claw portion 7 are provided. The protruding cylinder portion 4 has a large-diameter hole portion 28 that opens to the distal end side of the protruding cylinder portion 4 and a small-diameter hole portion 29 that is connected to the large-diameter hole portion 28 (via a taper portion).

  Next, a method for connecting (piping) the pipe 1 will be described. First, the pipe 1 is inserted into the joint body 5 and brought into contact with the inner peripheral surface 20 of the tapered hole 9. When the cap nut 2 is screwed into the male screw 3 from the state where the cap nut is not screwed (see FIGS. 1 and 6), the tip portion 10 of the claw portion 7 is pressed against the pipe outer peripheral surface 11 and the pipe tip 12 is moved. While moving to the back of the joint body 5, it moves to the nail biting state (see FIGS. 2 and 7), and the pipe tip 13 is in close contact with the inner peripheral surface 20 of the taper hole 9 (FIG. 2). (See FIG. 7). For example, when connecting a pipe 1 having an outer diameter of 20 mm, the tip end is sealed by moving about 2 mm from the initial contact position X to the inner peripheral surface 20 of the pipe 1 in the axial direction back. Since the movement of the pipe 1 to the back and the deformation and biting of the claw portion 7 proceed almost simultaneously, the cap nut 2 can be screwed with a small torque.

That is, when the pipe 1 is not moved to the deeper of the joint body 5 (Comparative Example), the pipe 1, as shown in FIGS. 10 and 11, longitudinally long dimension L ₂ (large) scars Z is formed Therefore, a large torque is required to screw the cap nut 2. On the other hand, when the pipe 1 moves to the back of the joint body 5 as in the present invention, only a small scar 30 is formed on the pipe 1 as shown in FIGS. The cap nut 2 can be screwed.
In other words, in the former (FIGS. 10 and 11), since the claw portion 7 bites in while cutting the outer peripheral surface 11 of the pipe 1, a large amount of energy is required, and the (rotation) torque for rotating the cap nut 2 is large. In the latter case (FIGS. 8 and 9), the tip 10 of the claw 7 bites in as if it is pushed inward in the radial direction without cutting the outer peripheral surface 11 of the pipe 1, and small energy is sufficient. The (rotational) torque for rotating 2 is reduced.

  In the tip close state, the pressure contact portion P between the pipe tip 12 and the inner peripheral surface 20 of the taper hole 9 forms a first-stage sealing action (temporary sealing), and in the region Y where the O-ring 24 is disposed, Gas or liquid (deteriorating the O-ring 24) such as chlorine gas or active oxygen is difficult to enter. Accordingly, the life of the O-ring 24 can be extended.

The claw portion 7 will be described in detail. In a state where the cap nut is not screwed, the thick portion 17 of the claw portion 7 is inclined so as to incline radially inward as it moves in the distal direction, and the cap nut 2 is screwed. Accordingly, a pressing force F (see FIG. 6) acts on the thick portion 17 from the cap nut 2 via the friction reducing member 21, and the thick portion 17 is pressed inward in the axial direction by the cap nut 2. The thin base portion 16 is folded (folded) so as to approach the orthogonal plane (see FIG. 7), and the nail biting state is entered. Through the cylindrical portion 22 of the friction-reducing member 21, the inner circumferential surface 2A radial direction within the clearance regulating force F ₂ is applied from the cap nut 2 with (see Fig. 6), the thin base portion 16 in the radial outward Suppress deformation that escapes.
The escape regulating force F _2, the inner circumferential surface 2A of the cap nut 2, by acting on the outer surface of the thin base 16 of the claw portion 7, when the slide into sequentially changed in FIG 6, the claw portions 7 The tip portion 10 (small convex portion 19) of the pipe 1 bites into the outer peripheral surface 11 of the pipe 1 deeply.

With the deformation of the claw portion 7, the pressing ring 25 presses the O-ring 24, and the O-ring 24 moves from the large-diameter hole portion 28 to the small-diameter hole portion 29 (backward). As shown in FIGS. 1 and 6, since the O-ring 24 is disposed in the large-diameter hole 28 when the cap nut is not screwed, the pipe tip 13 may be damaged when the pipe 1 is inserted. Can be prevented. And the pipe 1 can be inserted easily. Also, if the cap nut 2 is forgotten to be tightened or insufficiently tightened, there is an initial leak, so that it can be easily checked.
In the present invention, the folding operation of the claw portion 7 from FIG. 6 to FIG. 7 is skillfully used for switching the O-ring 24 to the full-sealed state, thereby simplifying the structure. It is what.

FIG. 12 shows a second embodiment. The friction reducing member 21 (see FIGS. 1, 2, 6, and 7) is omitted, and the cap nut 2 directly presses the claw portion 7. That is, the pressing force F and the escape restriction force F ₂ are applied directly to the claw portion 7 from the cap nut 2. A contact 27 is formed on the inner peripheral surface 26 of the cap nut 2. Other configurations are the same as those of the first embodiment.

  13 and 14 show a third embodiment. The cap nut 2 has a first concave circumferential groove 33 for accommodating a first seal member (O-ring) 32 on the inner peripheral surface 31 on the front end side. The first seal member 32 is accommodated in the first concave groove 33. The cap nut 2 has a second concave circumferential groove 36 for accommodating the second seal member 35 (O-ring) on the inner peripheral surface 34 of the intermediate portion. The second seal member 35 is accommodated in the second concave circumferential groove 36. The “intermediate portion” refers to a portion corresponding to a position in the axial direction between the female screw 40 of the cap nut 2 and the axial center orthogonal wall portion 41.

The projecting tubular portion 4, a small diameter outer circumferential surface 37 of the distal outer diameter D _1, the large-diameter outer peripheral surface 38 of the larger outer diameter D ₂ from the distal side outer diameter D ₁ is, with a stepped slope portion 39, is formed. The large-diameter outer peripheral surface 38 is formed smoothly. In the state where the cap nut is not screwed (see FIG. 13), the second seal member 35 is disposed at a position corresponding to the small-diameter outer peripheral surface 37 in the axial direction. Is configured to ride on the large-diameter outer peripheral surface 38 beyond the stepped slope 39 and seal (see FIG. 14). There is an advantage that fluid such as water does not enter the threaded portion (the female screw 40 of the cap nut 2 and the male screw 3 of the joint body 5). Other configurations are the same as those of the second embodiment.

15 and 16 show a fourth embodiment. The second concave circumferential groove 36 is formed on the outer peripheral surface 42 on the base end side from the male screw 3 of the joint body 5. In the state where the cap nut is not screwed (see FIG. 15), the base end 43 of the cap nut 2 does not press the second seal member 35. In the state where the cap nut is bitten (see FIG. 16), the cap nut 2 causes the second seal member 35 to be pressed. Is configured to be pressed and sealed. Other configurations are the same as those of the third embodiment. In the initial leak inspection, if the cap nut 2 (the smooth inner peripheral surface 45 on the base end side) is forgotten to be tightened, fluid (water or hot water) leaks, which is easy to understand. Furthermore, it is possible to check whether the cap nut 2 is forgotten to be tightened by checking whether the second seal member 35 is visible (that is, visually). In particular, the second seal member 35 is preferably colored in a bright color (for example, red, yellow, etc.). Compared to the third embodiment, with the advantage of being able to reduce the outer diameter D ₃ of the cap nut 2 (compact is), can be easily manufactured.

Here, a further additional description will be given. Specifically, the claw portion 7 can be easily and stably manufactured in the joint body 5 by the lost wax method, and a small component (in a conventional pipe joint). It is possible to simplify the assembly work without worrying about loss. As shown in FIGS. 5 and 4, the outer surface of the thin base portion 16 and the outer surface shape of the thick portion 17 of the claw portion 7 (in the longitudinal section) are smoothly continuous curves (or a straight line). In addition, since the outer peripheral surface 4A in the vicinity of the distal end surface 6 of the protruding cylindrical portion 4 and the outer surface of the thin base portion 16 (without a step) are formed in a continuous linear shape, the following advantages are obtained. There is. (i) When the cap nut 2 is externally fitted, the cap nut 2 is not caught by the inner surface of the cap nut 2, the friction reducing member 21 or the like, and is not deformed abnormally. (ii) When the nail | claw part 7 is bent like FIGS. 6-7, it does not receive damage, such as a crack. (iii) When the claw portion 7 is bent as shown in FIGS. 6 to 7, the bent shape (FIG. 7) is stable, the biting into the outer peripheral surface 11 of the pipe 1 is stable, and the anti-pulling resistance There is no variation in force. (iv) The relief regulating force F ₂ shown in FIGS. 6 and 7 acts on the outer surface of the claw portion 7 reliably.

  Next, the inner side surface shape of the claw portion 7 is clearly a rounded curved surface (16A) in the thin base portion 16, and the claw portion 7 is smoothly bent as shown in FIGS. It is done. In addition, the cross-sectional shapes of the thick portion 17 and the small convex portion 19 make it possible to smoothly and firmly bite into the pipe outer peripheral surface 11 as a bowl shape.

As described above, as the cap nut 2 is screwed into the male screw 3, the tip portion 10 (small convex portion 19) of the claw portion 7 is pressed against the pipe outer peripheral surface 11 as shown in FIGS. since shifts to nail biting state while the pipe tip 12 is pushing moved deeper of the joint body 5 while, as compared with the case of a pipe fixed in the comparative example of FIGS. 10 and 11, for scraping the long dimension L ₂ Unnecessary energy is saved, and in the present invention, as shown in FIGS. 8 and 9, scars 30 that are sufficiently deeply punctured in the radial direction can be formed with less energy. Accordingly, the screwing operation of the cap nut 2 can be performed quickly with a small rotational torque. Moreover, in the present invention, the operation of moving the pipe tip 12 to the back of the joint body 5 is skillfully utilized for the first stage seal (temporary sealing). That is, with respect to the outer diameter of the pipe 1 to be used, the inner diameter of the hole 8 of the joint body 5 is set in advance so as to be in the state shown in FIG. 6) as shown in FIG. 6 to FIG. 7 as the cap nut 2 is screwed thereafter. Existence of the O-ring 24 in FIG. 7 due to the (relatively) strong pressure contact of the outer peripheral end of the pipe tip 13 to the small diameter part at the back of the hole 9 (and the pressure contact part P having a predetermined width). The region Y to be sealed is sealed so that a (harmful) gas or liquid such as chlorine gas or active oxygen is difficult to enter. Since this seal is not a perfect seal, in the present invention, it is called “temporary seal”, or because it is a seal before the seal by the full-scale O-ring 24, it is called “first stage seal”.
Thus, in the present invention, the operation of moving the pipe tip 12 to the back (described above) is skillfully utilized for the first stage seal (temporary sealing).

  The design of the present invention can be changed. For example, the number of the claw portions 7 can be freely increased and decreased, for example, three or seven. Further, the formation of the contact 27 in the second embodiment may be omitted. Moreover, it is good also as a structure which provided the member 21 for friction reduction shown in 1st Embodiment in 3rd Embodiment and 4th Embodiment.

As described above, the present invention relates to a projecting cylinder in a pipe joint structure including a cap nut 2 and a joint body 5 having a projecting tube portion 4 with a male screw 3 on which the cap nut 2 is fitted. A plurality of claw portions 7 project from the distal end surface 6 of the portion 4, and the pipe insertion hole 8 of the projecting cylindrical portion 4 is formed in a tapered hole 9 that expands (slightly) in the distal direction. When the cap nut 2 is screwed into the male screw 3, the tip 10 of the claw 7 is brought into pressure contact with the outer peripheral surface 11 of the pipe, and the pipe tip 12 is pushed and moved to the back of the joint body 5 to shift to the claw biting state. In addition, since the tip 13 of the pipe is in close contact with the inner peripheral surface 20 of the taper hole 9 when the pipe 1 is connected, unnecessary cutting of the pipe outer peripheral surface 11 (FIG. 10). , most distal portion 10 is radial in direction of the claw portion 7 without generating long dimension L ₂ scars Z) as shown in FIG. 11 Since the bite is bitten, the cap nut 2 can be rotated with a small rotational torque. In addition, it exhibits a sufficient retaining force and withstands a water hammer. In addition, since the life of the O-ring 24 made of a normal material such as nitrile rubber can be extended, it is possible to use such an O-ring 24 (no need for a corrosion-resistant seal) and manufacture at a low cost. can do. In addition, the number of parts is reduced, and manufacturing and assembly can be easily performed, and manufacturing can be performed at low cost.

Further, the claw portion 7 is connected to the outer peripheral edge 15 of the distal end surface 6 of the protruding cylindrical portion 4, the thick portion 17 thicker than the thin base portion 16, and the distal end of the thick portion 17. 18 and a small protruding portion 19 for biting, and when the cap nut is not screwed, the thick portion 17 is inclined so as to incline radially inward as it goes in the tip direction. As the screw 2 is screwed, the thick nut 17 is pressed axially inward by the cap nut 2 and bent around the thin base 16 so as to approach the plane orthogonal to the axial center. Since it comprised so, the nail | claw part 7 can be deform | transformed with the small pressing force F. FIG. Further, the claws bite condition, a radial inward direction of the relief control force F ₂ from the inner circumferential surface 2A of the cap nut 2 acts to the pipe outer peripheral surface 11 via the thick portion 17, the compressive force of greater radial (Regulation The claw part 7 can sufficiently withstand the force F ₂ ). Moreover, the thin-walled base 16 bends securely and smoothly (as shown in FIGS. 6 to 7), approaches the axial center plane as if the claw 7 was folded, and is always stable in the nail biting state. Transition and exert a strong pipe pull-out resistance.

2 Cap nut 3 Male screw 4 Projection cylinder 5 Joint body 6 Tip surface 7 Claw 8 Pipe insertion hole 9 Taper hole
10 Tip
11 Pipe outer peripheral surface
12 Pipe end
13 Pipe cutting edge
15 Outer edge
16 Thin base
17 Thick part
18 Tip
19 Small convex part for biting
20 Inner surface

Claims (2)

In a pipe joint structure comprising: a cap nut (2); and a joint body (5) having a protruding cylindrical portion (4) with a male screw (3) to which the cap nut (2) is fitted.
A plurality of claw portions (7) are projected from the tip surface (6) of the protruding cylindrical portion (4),
Further, the pipe insertion hole (8) of the protruding cylinder (4) is formed in a tapered hole (9) whose diameter increases in the distal direction.
When the cap nut (2) is screwed into the male screw (3), the tip end (10) of the claw portion (7) is pressed against the pipe outer peripheral surface (11), and the pipe tip (12) is joined. To move to the nail biting state while pushing and moving to the back of the main body (5), and to bring the tip of the pipe (13) into a state of close contact with the inner peripheral surface (20) of the tapered hole (9). Constructed pipe joint structure.   The claw portion (7) is connected to the outer peripheral edge (15) of the distal end surface (6) of the protruding cylindrical portion (4), and is thicker than the thin base portion (16). And a biting small convex portion (19) connected to the tip (18) of the thick portion (17), and when the cap nut is not screwed, The thick part (17) is inclined in the radial inward direction as it goes in the distal direction, and the thick part (17) is formed by the cap nut (2) as the cap nut (2) is screwed. 2. The pipe joint structure according to claim 1, wherein the pipe is bent about the thin base portion (16) so as to be pressed axially in the axial direction and approach a plane orthogonal to the axial center, and shifts to the nail biting state.

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