JP6356893B1 - Pipe joint structure - Google Patents

Abstract

A pipe joint structure that is compact in the axial direction, has a small number of parts, and is easy to manufacture. The first and second pipes (P1) and (P2) are formed with a tip enlarged pipe portion (5), and each of the cap nut (15) and the cap bolt (20) includes the tip enlarged tube. The cap nut (15) and the cap bolt (20) are directly connected by the male and female screw means (Z). [Selection] Figure 1

Description

  The present invention relates to a pipe joint structure.

  Conventionally, a pipe joint structure for connecting pipes to each other has a structure in which one pipe is connected to one end of the joint body and the other pipe is connected to the other end of the joint body ( (See Patent Documents 1 and 2).

Japanese Patent Laying-Open No. 2015-137664 Japanese Patent No. 3568906

FIG. 8 shows the pipe joint structure described in Patent Document 1, in which the cap nuts 43 and 44 are screwed into the male screws 41 and 42 at both ends in the axial center direction of the joint main body 40 and are held by the retainer 46. the cone 45, is pressed into the radial inward direction by the tapered pressing the inner surface of the cap nut 43, is a structure for the pull-out blocking by plastically deforming the first pipe P ₁ · second pipe P ₂ from the outer peripheral surface .
That is, the first pipe P ₁ is connected (connected) to the joint body 40 by screwing the cap nut 43 onto the male screw 41 on the left side of the joint body 40, and the other second pipe P ₂ is connected to the joint body 40. In this structure, the cap nut 44 is screwed into the right male screw 42 to be connected (connected) to the joint body 40. In short, the joint body 40 is essential, and the first and second pipes P ₁ and P ₂ are interconnected with the cap nuts 43 and 44 through the joint body 40.

FIG. 9 shows the pipe joint structure described in Patent Document 2, and the joint body 40 includes cylindrical portions 48 and 48 with tapered female threads 47 and an intermediate portion 49. The left and right screw fastening cylinders 50 and 50 are screwed together. A plurality of elongated holes are provided in the circumferential direction in the screw fastening cylinder 50, and a continuous bead 52 having three independent small ridges 51, 51, 51 is fitted into the elongated holes. By rotating the portion 48 in the direction of the arrow T, the tightening cylinder 50 is screwed inwardly of the joint body 40, and the continuous bead 52 is rotated and revolved on the outer peripheral surfaces of the pipes P ₁ and P _2. the helical groove 54 (in plastic deformation) are formed, a state Renju like body 52 bites into the outer circumferential surface of the pipe P _1, P _2, pipe P _1, so that P ₂ has no pull-out from the joint body 40 It is a connected structure.
In short, in the case of FIG. 9 as well, the joint body 40 is indispensable, and the first and second pipes P ₁ and P ₂ are provided with the threaded fastening cylinder 50 and the continuous body 52 with the joint body 40 interposed. Are connected in the pull-out prevention state.

As described above, the pipe joint structure described in FIG. 8 (Patent Document 1) and FIG. 9 (Patent Document 2) has the following problems. In other words, (i) The number of parts is large, the structure is complicated, the production is troublesome, and the production cost cannot be reduced. (ii) The overall axial dimension is large and the volume of the pipe joint structure is large.
Therefore, the present invention aims to solve such problems (i) and (ii), and to provide a compact pipe joint structure that is low in the number of parts, inexpensive, easy to manufacture.

The present invention relates to a pipe joint structure in which a first pipe and a second pipe are connected to each other; each of the first and second pipes is subjected to a diameter-expanding plastic working over a predetermined axial direction dimension from the tip surface. A single tip diameter expansion tube portion having the same outer diameter is formed; a taper stepped portion is formed at the boundary between the tip diameter expansion tube portion and the basic diameter tube portion; A cap nut and a cap bolt having a seal groove having a contact portion and a seal groove in close contact with the outer peripheral surface of the tip enlarged pipe portion; In the connection completion state, the first pipe and the second pipe each have a relative circumference between the sloped portion and the tapered stepped portion. It can be rotated around the pipe axis by sliding in the direction, and the slope and taper As drawn prevented by mutual pressure contact between the stepped portion is constituted; Moreover, in the connection completed state, the first pipe and the second pipe is rotatable relative pipe axis around.

Further, in the connection completion state, the shaft of the tip diameter-expanded tube portion is formed so that a minute gap is formed between the tip surfaces of the first pipe and the second pipe or the tip surface is lightly contacted. The center direction dimension and the distance between both gradient parts are set, and no solid matter is present in the minute gap, so that the first pipe and the second pipe can rotate around the pipe axis relatively. It is configured.
In addition, the cap nut and the cap bolt are provided with first and second metal seal portions that are pressed against each other in a state where the cap nut and the cap bolt are interconnected by the male and female screw means. Yes.

  According to the pipe joint structure of the present invention, the number of parts is extremely small, and the size can be reduced. Manufacturing is also easy and cost reduction is possible. In addition, connection work can be performed efficiently.

It is sectional drawing of the connection completion state which shows one Embodiment of this invention. It is sectional drawing which shows a cap bolt. It is sectional drawing which shows a cap nut. It is sectional drawing which shows an unconnected state. It is sectional drawing of the connection completion state which showed the modification. It is sectional drawing explaining the principal part and diameter expansion method of a formation work tool of a front-end | tip enlarged diameter pipe part. It is sectional drawing for demonstrating the description of the brazing operation currently implemented from old to the present, and the pipe connection part brazed. It is sectional drawing which shows a prior art example. It is sectional drawing which shows another prior art example.

Hereinafter, the present invention will be described in detail based on the illustrated embodiment.
As shown in FIGS. 1 and 4, the first pipe P ₁ and the second pipe P ₂ each have a distal end diameter-expanded tube portion 5 extending from the distal end surface 3 over a predetermined axial direction dimension L ₅ .
A tapered stepped portion 10 is formed at the boundary between the tip diameter-expanded tube portion 5 and the basic diameter tube portion 6 having the original basic diameter D ₀ of the pipe.
15 is a cap nut, and 20 is a cap bolt.

The cap nut 15 has a slope portion 11 that comes into contact with the tapered stepped portion 10 of the second pipe P ₂ , and is a sealing material such as an O-ring that is in close contact with the outer peripheral surface of the tip enlarged pipe portion 5 and has a sealing action. 7 has a seal ditch 8 in which 7 is housed.
Further, the cap nut 15 has a female screw portion 12. The seal concave groove 8 and the female screw portion 12 are partitioned by an inner flange-shaped partition wall portion 13. The outer shape of the cap nut 15 is a general hexagonal cross section, knurled, or formed with numerous concave grooves in the axial direction and held by the operator's hand and work tool. It is easy to do, and it is set as the shape which can give a big torque.
In this way, the cap nut 15 has the inner peripheral end surface of the inner flange portion 16 on the outer side of the joint (right side in FIG. 1) as the inner diameter slightly larger than the original basic diameter D _{0 of the} pipe. It protrudes radially inward and surrounds the expanded pipe portion 5 of the second pipe P ₂ from the radial outside as shown in FIG.

Next, the cap bolt 20 has an inclined portion 11 that comes into contact with the tapered stepped portion 10 of the first pipe P ₁ , and an O-ring that is in close contact with the outer peripheral surface of the tip enlarged diameter pipe portion 5 to perform a sealing action. A seal groove 8 in which the seal material 7 is housed.
Further, the cap bolt 20 has a male screw portion 14. The portion 17 constituting the groove bottom wall portion of the seal concave groove 8 is the portion that protrudes most in the radial direction of the cap bolt 20, and the outer peripheral shape of the radial outermost position 17 is a general hexagonal cross section. Then, knurling is performed or a number of concave grooves are formed in the axial direction so that it can be easily gripped by the operator's hand and the work tool and a large torque can be applied.

  The slope portion 11 is formed on the inner peripheral end surface of the inner flange wall portion 18 extending radially inward from the portion 17 and radially inward so as to form the other side wall of the seal groove 8 from the portion 17. A cylindrical portion 21 is continuously provided from a radially inner end edge of the extended inner flange wall portion 19, and the male screw portion 14 is formed on the outer peripheral surface of the cylindrical portion 21. Further, the inner peripheral surface 21A of the cylindrical portion 21 corresponds to the tip diameter-expanded tube portion 5 as close to or abutting.

In this way, the cap bolt 20 has an inner peripheral end surface of the inner flange wall portion 18 on the outer side of the joint (left side in FIG. 1) as an inner diameter slightly larger than the basic diameter D _{0 of the} pipe body. As shown in FIG. 1, it projects most radially inward and surrounds the expanded pipe portion 5 of the first pipe P ₁ from the radially outer side, which is a “bag type”.
As described above, the cap bolt 20 and the cap nut 15 are both “bag-type”, and in particular, the term “cap bolt” is not widely used in general. In this case, the term “cap bolt” is used after “cap nut”.

And (as shown in FIGS. 4 to 5), the cap nut 15 and the cap bolt 20 are screwed together (by a male and female screw means Z comprising a female screw portion 12 and a male screw portion 14). Link).
As described above, the joint body is omitted (not at all) as a configuration in which the cap nut 15 and the cap bolt 20 are interconnected.
That is, a member corresponding to the joint body 40 of FIGS. 8 and 10 showing the conventional example is omitted.
Moreover, as shown in FIG. 1, an axial center is formed so as to form a minute gap G or lightly contact between the front end surfaces 3 and 3 of the first pipe P ₁ and the second pipe P _2. The direction dimensions L ₅ and L ₅ and the distance between the two slope portions 11 and 11 under the connected (connected) state are set.

Since the setting is made as described above, the first pipe P ₁ and the second pipe P _{2 with} respect to the cap nut 15 and the cap bolt 20 in the connected state are relative to each other between the slope portion 11 and the tapered stepped portion 10. It can rotate around the pipe axis Lp by sliding in the circumferential direction, and is prevented from being pulled out by mutual pressure contact between the gradient portion 11 and the tapered stepped portion 10. In FIG. 1, an arrow Y indicates a pulling force acting on the pipes P ₁ and P ₂ , and a strong pulling prevention force can be exerted against the pulling force Y.

FIG. 5 shows a modified example. In FIG. 5, reference numeral 25 denotes a short circular tubular spacer, and both ends of the spacer 25 are arranged with respect to the inner surfaces of the gradient portions 11 and 11 of the first and second pipes P ₁ and P _2. It is arranged (interior) in an approaching or abutting manner. Preferably, a pipe material having the same material and diameter as the first and second pipes P ₁ and P ₂ is cut into a ring shape. By adding such a spacer 25, the pull-out preventing force can be increased.
That is, when the first and second pipes P ₁ and P ₂ are easily deformed from the surface of the material or thickness, the spacer 25 has a function of reinforcing from the inner peripheral side.

In FIG. 5, if the first and second pipes P ₁ and P ₂ are pulled out by the pulling force in the direction of the arrow Y, the tip diameter-expanded pipe portion 5 is narrowed by the slope portion 11. Must be reduced in diameter.
The spacer 25 exerts a reinforcing function to prevent this diameter reduction deformation. In addition, there is an advantage that the fluid passage pressure loss can be reduced by making the inner diameter dimension of the spacer 25 and the first and second pipes P ₁ and P ₂ the same.
In the modification shown in FIG. 5, the same reference numerals as those in FIG.

Next, the sealing function will be described with reference to FIGS. The sealing materials 7 and 7 such as O-rings that are pressed against and sealed to the outer peripheral surface of the distal end diameter-expanded pipe portion 5 have already been described, but the other sealing portions have a metal seal structure by pressure welding between metals.
Specifically, the cap nut 15 and the cap bolt 20 are sealed by the first and second metal seal portions S ₁ and S ₂ in a state where the cap bolt 20 is connected by the male and female screw means Z.
The first metal seal portion S ₁ includes a partition wall portion 13 and a tip portion 21B (pressure contact) of the cylindrical portion 21 having the male screw portion 14. The second metal seal portion S ₂ is composed of the outer end of the cylindrical portion having the female screw portion 12 of the cap nut 15 and the outer surface (pressure contact) of the inner flange wall portion 19 of the cap bolt 20.

Next, with reference to FIG. 6 and FIG. 7, a manufacturing (processing) method and the like of the distal diameter expanding pipe portion 5 will be described.
As shown in FIG. 6, the tip of the pipe P _{0 to} be processed is inserted into the hole 26A of the split mold 26, and the fan-shaped diameter-expanded piece 27 divided into four (or more) cross sections is pipe P. Insert at a predetermined depth with respect to _zero . If the tapered male die 28 is pushed in the direction of the arrow E into the tapered hole 29 formed by the divided enlarged diameter piece 27, the enlarged diameter piece 27 as shown in FIGS. There move the radial outward direction R, the diameter plastic working, distal enlarged tube part 5 is made form.

In order to form the tapered stepped portion 10, the diameter-expanded piece 27 is provided with a tapered portion 27 A, and the hole portion 26 A of the mold 26 is provided with a tapered portion 26 B.
Thereafter, the mold 26 is divided and operated in the diameter increasing direction, and the processed pipe P ₀ is pulled out, thereby producing pipes P ₁ and P ₂ with the tip diameter expanding pipe portion 5 as shown in FIG.

For a long time, the diameter expansion manual operation tool shown in FIG. 6 has been widely known. The reason for this is that the brazed pipe connection 33 as shown in FIG. 7 has been used for refrigerant piping and domestic hot water supply (water) piping since ancient times. In other words, because of the brazing pipe connection 33 that has been practiced for a long time, it was necessary to pre-process the tip diameter-expanded pipe portion 5 shown in FIGS. is there. (Note that the other pipe 32 is inserted into the expanded diameter pipe portion 5 as it is without being processed, and the mutual fitting surface portion X is brazed.)
As described above, the present inventor has focused on the diameter expansion work tool widely used for the pipe connection work by brazing and the tip diameter expansion pipe portion that can be easily processed thereby, and FIGS. By combining the unique shape and structure shown in the figure, it is possible to work safely without using heat such as brazing, and it is compact in both the axial (axial) direction and radial direction. A pipe joint structure with excellent connection workability is proposed here.

The present invention is not limited to the above-described embodiments unless the gist thereof is changed, and the design can be freely changed. For example, the two metal seal portions S ₁ and S ₂ are made of a sealing material such as an O-ring. The structure used is also free (not shown).
The fluid to which the pipe joint structure of the present invention can be applied is free of refrigerant, gas, air, water, hot water, etc., but the first and second pipes P ₁ and P ₂ are copper, aluminum, and stainless steel that can be easily expanded. Metals such as steel are preferred. When the fluid is water, hot water or the like containing a refrigerant, gas, or chlorine gas, the seal material 7 is preferably made of a corrosion resistant rubber. Since the recent progress of corrosion-resistant rubber materials is remarkable, the applicable fluid of the pipe joint structure provided with the sealing materials 7 and 7 as in the present invention is water, hot water containing refrigerant, corrosive gas, chlorine gas, etc. It can be said that there is a high possibility of expansion.

As described in detail above, the present invention provides a pipe joint structure for connecting the first pipe P ₁ and the second pipe P ₂ to each other; the first and second pipes P ₁ and P ₂ are respectively A tip diameter-expanded tube portion 5 is formed from the tip surface 3 over a predetermined axial dimension L ₅ ; a tapered stepped portion 10 is formed at the boundary between the tip diameter-expanded tube portion 5 and the basic diameter tube portion 6. A cap nut 15 and a bag having a seal recess groove 8 having a slope portion 11 abutting against the tapered stepped portion 10 and having a seal material 7 in close contact with the outer peripheral surface of the tip enlarged diameter pipe portion 5. Bolt 20 is provided; the cap nut 15 and the cap bolt 20 are connected to each other by the male and female screwing means Z, so that the number of parts is reduced, the manufacturing is easy, and the cost can be reduced. In particular, the overall axial center direction (axial direction) size is reduced, and compactness can be achieved. In addition, the work of forming the tip expanded pipe portion 5 is applied with a work tool that has been used for a completely different connection method since ancient times, so that a piping worker can work easily and quickly. The whole work can be done efficiently and quickly.

  Further, in the present invention, since the joint body is omitted by connecting the cap nut 15 and the cap bolt 20 to each other, the axial center direction (axial direction) can be made compact, and the number of parts can be reduced. And the structure can be simplified. (This point becomes clear when compared with FIGS. 8 and 9 showing the conventional example.)

When the connection is completed, the first pipe P ₁ and the second pipe P ₂ are each in the relative circumferential direction of the gradient portion 11 and the tapered stepped portion 10 with respect to the cap nut 15 and the cap bolt 20. Since it is configured to be able to rotate around the pipe axis Lp by sliding and to be prevented from being pulled out by mutual pressure contact between the gradient portion 11 and the tapered stepped portion 10, the male and female screwing means Z is provided. During the screwing operation, rotation is not transmitted to the other end of the pipe via the pipes P ₁ and P ₂ . As a result, it is possible to prevent an accident in which another pipe joint is loosened unexpectedly at the other end of the pipe. On the other hand, when the rotational torque is transmitted from the other end or the middle of the pipes P ₁ and P ₂ , the rotational torque is not transmitted to the male and female screwing means Z. Therefore, the cap nut 15 and the cap bolt 20 are Accidents that rotate and loosen relatively can also be prevented.

3 Tip surface 5 Tip diameter expanding pipe part 6 Basic diameter pipe part 7 Sealing material 8 Seal groove
10 Tapered stepped part
11 Slope
15 Cap nut
20 Cap bolt P ₁ 1st pipe P ₂ 2nd pipe L ₅ Axial dimension Lp Pipe axis
G Micro gap Z Male / female screwing means S ₁ 1st metal seal part S ₂ 2nd metal seal part

Claims (3)

In the pipe joint structure for connecting the first pipe (P ₁ ) and the second pipe (P ₂ ) to each other,
Each of the first and second pipes (P ₁ ) and (P ₂ ) has a single tip having the same outer diameter by diameter-expanding plastic working from the tip surface (3) to a predetermined axial direction dimension (L ₅ ). An expanded pipe portion (5) is formed,
A tapered stepped portion (10) is formed at the boundary between the tip diameter-expanded tube portion (5) and the basic diameter tube portion (6).
A seal ditch (8) having a slope portion (11) that contacts the tapered stepped portion (10) and having a seal material (7) in close contact with the outer peripheral surface of the tip enlarged diameter pipe portion (5). A cap nut (15) and a cap bolt (20) having
The cap nut (15) and the cap bolt (20) are connected to each other by male and female screwing means (Z). When the connection is completed, the cap nut (15) and the cap bolt (20) Each of the first pipe (P ₁ ) and the second pipe (P ₂ ) has a pipe axis (Lp) due to relative sliding in the circumferential direction between the gradient portion (11) and the tapered stepped portion (10). It is configured to be able to rotate around and to be prevented from being pulled out by mutual pressure contact between the gradient portion (11) and the tapered stepped portion (10) .
In addition, the pipe joint structure is characterized in that the first pipe (P ₁ ) and the second pipe (P ₂ ) are relatively rotatable around the pipe axis (Lp) in the connection completion state . When the connection is completed, a small gap (G) is formed between the tip surfaces (3) and (3) of the first pipe (P ₁ ) and the second pipe (P ₂ ), or lightly the tip. The axial dimension (L ₅ ) (L ₅ ) of the tip expanded diameter pipe portion ( ₅ ) and the distance between both gradient portions (11) and (11) are set so that the surfaces (3) and (3) are in contact with each other. The first gap ( P ₁ ) and the second pipe (P ₂ ) are relatively rotated around the pipe axis (Lp) without any solid matter in the fine gap (G). The pipe joint structure according to claim 1, which is configured to be possible. In the state where the cap nut (15) and the cap bolt (20) are interconnected by the male and female screwing means (Z), the cap nut (15) and the cap bolt (20) are pressed against each other. The pipe joint structure according to claim 1 or 2, further comprising first and second metal seal portions (S ₁ ) and (S ₂ ).

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