JP2010038268A - Resin pipe joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin pipe joint compatibly attaining pull-off resistance and good sealing performance, economically comprising two members, namely, a joint body and a union nut. <P>SOLUTION: The resin pipe joint includes the fluororesin joint body 1 having an inner cylinder portion 4 and a male screw 5, and the fluororesin union nut 2 having a female screw 8, a seal thrusting portion 10 operable on a small-diameter side portion of a diameter-enlarged change region 9 on a tube 3, and an anti-come-off inner screw 11 operable on a diameter-enlarged straight portion 12 of a diameter-enlarged portion 3A. As the union nut 2 is threaded with the fastening turn operation in the state that the end of the tube 3 is externally fitted and mounted onto the inner cylinder portion 4 to form the diameter-enlarged portion 3A, the small-diameter side portion of the diameter-enlarged change region 9 is thrust toward an axial center P by the seal thrusting portion 10 and the diameter-enlarged straight portion 12 is thrust in the radial direction by the anti-come-off inner screw 11. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a resin pipe joint having a structure in which a tube as a fluid transfer path is expanded (flared) and connected, and more specifically, in various technical fields such as semiconductor manufacturing, medical / pharmaceutical manufacturing, food processing, chemical industry, etc. It is also suitable for piping of high-purity liquid and ultrapure water handled in the manufacturing process, and relates to a resin pipe joint used as a connecting means of a tube that is a fluid device such as a pump, a valve, a filter, or a fluid transfer path. .

  As this type of resin pipe joint, a tube joint disclosed in Patent Document 1 is known. That is, the tube 1 made of synthetic resin is forcibly pushed into the inner tube portion 5 of the joint body 4 or, as shown in FIG. It fits in part 5. Then, the union nut 6 fitted in the tube in advance is screwed into the joint body, and is tightened to forcibly move in the axial direction of the joint body 4, so that the enlarged root portion 2 a of the tube 1 is edged. This is a structure in which the portion 6 a is pressed strongly in the axial direction to seal between the tube 1 and the inner cylinder portion 5.

  As the structure similar to the above-described structure, the one disclosed in FIGS. 8 and 9 of Patent Document 2 and the resin pipe joint disclosed in FIG. 6 of Patent Document 3 are known. As described above, the joint structure in which the tip of the tube is expanded (flared), fitted into the joint body, and fastened with a nut is the structure disclosed in FIG. 5 of Patent Document 2, FIG. 5 of Patent Document 3, or the like, Compared to a three-part pipe fitting that has a tube end fitted to the inner ring of the dedicated part with an expanded outer diameter fitted in the tubular receiving port of the fitting body and is fastened with a union nut, the joint body and union nut are fewer parts There is an advantage that a good sealing function can be obtained while economically constituting a pipe joint with two points.

  However, in the conventional resin pipe joint composed of two parts as described above, the tube end is expanded and firmly fitted, and the expanded root portion is tightened with a union nut. There was a tendency for the force to pull out the tube from the joint body to be relatively weak, probably because it was for the purpose of functioning. Although the tube itself is pulled out and moved, there is also a problem that the sealing point due to the pressing of the edge portion is also shifted and the sealing performance is adversely affected. In particular, when the resin pipe joint is formed of a resin material having a large expansion coefficient such as a fluororesin so as to handle a high temperature fluid of 100 ° C. or higher, those problems become more prominent.

Therefore, as disclosed in Patent Document 4, a drawing-proof means having a structure in which a C-shaped split ring is interposed between the tube enlarged portion and the union nut in a state of being fitted in the circumferential groove of the tube enlarged portion. It is known to provide a resin pipe joint that is strong not only for the sealing function but also for pulling out the tube. However, the resin pipe joint disclosed in Patent Document 4 requires a pre-treatment for forming a circumferential groove in the tube enlarged portion in advance, and the number of parts is increased to 3 parts. A new problem arises that the economic efficiency is impaired. Therefore, there is still room for further improvement in making the resin pipe joint consisting of the joint body and the union nut strong against pulling out without causing new problems. .
Noto 3041899 Japanese Patent Laid-Open No. 7-27274 JP 2002-357294 A Noto 2587449 gazette

  In view of the above circumstances, an object of the present invention is a resin pipe that can achieve both a pull-out resistance and a good sealing property while being economical, consisting of a joint body and a union nut. The point is to provide a joint.

The invention according to claim 1 is a joint body 1 made of a synthetic resin, comprising an inner cylinder portion 4 which can be fitted and fitted with an enlarged end of the synthetic resin tube 3 in a resin pipe joint, as well as,
A female screw 8 that can be screwed onto the male screw 5, and a seal pressing portion 10 that can act on a small-diameter side portion of the enlarged-diameter changing region 9 in the enlarged-diameter portion 3 </ b> A that is externally fitted to the inner cylindrical portion 4 of the tube 3. A union nut 2 made of a synthetic resin comprising a retaining internal screw 11 that can act on the enlarged diameter straight portion 12 surrounded by the straight cylinder portion 4B having a constant diameter in the enlarged diameter portion 3A.
The joint main body 1 of the union nut 2 is formed by screwing the female screw 8 with the male screw 5 in a state where the end of the tube 3 is externally fitted to the inner cylindrical portion 4 to form the enlarged diameter portion 3A. Due to the screwing in the direction of the axis P, the small diameter side portion of the diameter expansion change region 9 is pressed in the direction of the axis P by the seal pressing part 10 and the diameter expansion straight part 12 is used for the retaining. The inner screw 11 is configured to be pressed in the radial direction.

  According to a second aspect of the present invention, in the resin pipe joint according to the first aspect, the retaining internal screw 11 is formed of a screw having a sharp thread y.

  The invention according to claim 3 is the resin pipe joint according to claim 1 or 2, wherein the retaining internal screw 11 and the female screw 8 are set at the same pitch. .

  According to a fourth aspect of the present invention, in the resin pipe joint according to the third aspect, a male screw 18 that can be screwed into the retaining internal thread 11 is formed in advance on the outer peripheral surface 12a of the diameter-enlarging straight portion 12. It is characterized by being.

  According to a fifth aspect of the present invention, in the resin pipe joint according to any one of the first to fourth aspects, the inner cylindrical portion 4 includes a tip tapered cylindrical portion 4A that gradually expands the diameter of the tube 3; And the straight barrel portion 4B formed subsequently to the large diameter side of the tip tapered tube portion 4A, and the diameter-changing region 9 of the tube 3 is the tip tapered portion. This is a portion covering the cylinder portion 4A.

  The invention according to claim 6 is the resin pipe joint according to any one of claims 1 to 4, wherein both the joint body 1 and the union nut 2 are made of a fluororesin.

  According to the first aspect of the present invention, the seal portion is formed at the tip end portion of the inner cylinder portion, and will be described between the inner cylinder portion and the enlarged diameter portion. The tube and the joint body can be satisfactorily sealed without entering. And, as the union nut is screwed, the internal screw for retaining is press-fitted as if it is screwed into the outer peripheral portion of the diameter-enlarging straight part, so that the thread is enlarged over the long distance. By pressing the straight portion, it becomes possible to strongly resist the force that the enlarged diameter portion tries to escape from the inner cylinder portion. As a result, it is possible to provide a resin pipe joint that can achieve both a pull-out resistance and a good sealing property while being economical, consisting of a joint body and a union nut.

  According to the invention of claim 2, the union nut is screwed so that the outer peripheral surface of the enlarged diameter straight portion is bitten by the internal screw for retaining, or the radial direction is just scratched. It comes to press strongly and there exists an advantage which the extraction-proof force improves.

  According to the invention of claim 3, while the union nut is tightened and turned, the screw pressing action to the enlarged diameter straight portion by the retaining inner screw is smoothly performed, and the union nut is loosened and turned. The unscrewing action of the retaining inner screw from the enlarged diameter straight portion is also smoothly performed. Therefore, there is an additional advantage that the union nut turning operation is hardly increased or reduced as much as possible due to the provision of the retaining inner screw.

  According to the invention of claim 4, when the union nut is rotated, there is no need for an action of cutting the diameter-expanded straight portion with an internal retaining screw, and an effective pull-out force is obtained. However, the union nut has the advantage that it can be operated lightly.

  According to the invention of claim 5, it is easy to perform external fitting to the inner cylinder part by expanding the diameter of the tube using the tapered part at the tip, and the effect of the pressing part for the seal on the diameter expansion change region. The location and the location of action on the diameter change region of the retaining pressing portion are separated from each other in the axial direction, making it easier to clearly demonstrate each of the sealing function and the retaining function. There exists an advantage which can strengthen the said effect by invention of 4th.

  According to the invention of claim 6, since both the joint body and the union nut are formed of a fluorine-based resin having characteristics excellent in chemical resistance and heat resistance, even if the fluid is a chemical liquid or a chemical liquid, Or even if it is a high-temperature fluid, a joint structure part does not deform | transform and it becomes easy to leak, and favorable sealing property and drawing-out force can be maintained now. Note that the fluorine-based resin is preferable in that it is stable at high temperatures, excellent in water repellency, has a small coefficient of friction, has extremely high chemical resistance, and has high electrical insulation.

  Embodiments of a resin pipe joint according to the present invention will be described below with reference to the drawings. 1 is a cross-sectional view of a resin pipe joint according to the first embodiment, FIG. 2 is an enlarged cross-sectional view of the main part of the resin pipe joint of FIG. 1, and FIG. 3 is an operation diagram showing the main part of the resin pipe joint according to the second embodiment. .

[Example 1]
As shown in FIGS. 1 and 2, the resin pipe joint A according to Example 1 includes a tube 3 made of a fluororesin (an example of a synthetic resin typified by PFA, PTFE, etc.), a fluid device such as a pump and a valve, A joint body 1 made of fluororesin (an example of a synthetic resin typified by PFA, PTFE, etc.) and a fluororesin (synthetic resin typified by PFA, PTFE, etc.) are connected to tubes of different diameters or the same diameter. An example) It is comprised by two parts with the union nut 2 made from. Each figure shows an assembled state in which the union nut 2 is tightened by a predetermined amount.

  As shown in FIGS. 1 and 2, the joint main body 1 is provided with an inner cylinder portion 4 at one end that can be fitted to the outside by expanding the diameter of the end portion of the tube 3, and a larger diameter than the inner cylinder portion 4. It is formed in the cylindrical member provided with the external male screw 5 of the outer periphery and the cylindrical space-like fluid path | route 7 with the axis P. The inner cylinder portion 4 has a straight tip cylinder portion 4A that gradually expands the diameter of the tube 3, and a straight barrel portion 4B that is formed on the large diameter side of the tip cone tube portion 4A. It is formed into a shape.

  The diameter of the part where the male screw 5 is formed is clearly larger than that of the straight barrel part 4B having the maximum diameter of the inner cylinder part 4, and the side peripheral wall 15 orthogonal to the axis P is formed. The tip surface of the inner cylinder part 4 is formed with a reverse taper angle that is closer to the inner inner side (the inner side in the direction of the axis P) toward the inner side in the radial direction. The shape of the liquid reservoir peripheral portion 17 due to the inner peripheral surface of the tube 3 being expanded and displaced toward the enlarged diameter portion (flare portion) is defined as the inner peripheral side expanded shape, and the fluid is stored in the liquid peripheral portion. 17 is difficult to stay. The cut surface 16 is formed so that the maximum diameter thereof is a substantially intermediate value between the inner diameter and the outer diameter of the tube 3 in the natural state, but this is not particularly concerned.

  As shown in FIGS. 1 and 2, the union nut 2 includes a female screw 8 that can be screwed into the male screw 5, and a small diameter of an enlarged diameter changing region 9 in the enlarged diameter portion 3 </ b> A that is externally fitted to the inner cylindrical portion 4 of the tube 3. A peripheral edge for sealing (an example of a pressing portion for sealing) 10 that can act on a side end portion (an example of a “small-diameter side portion”) and an enlarged straight portion 12 surrounded by a straight barrel portion 4B having a constant diameter. An internal thread 11 for retaining that can be actuated, and a guide cylinder portion 14 that surrounds the tube 3 over a predetermined length in the direction of the axis P following the sealing peripheral edge 10 are formed. The sealing peripheral edge 10 has an inner diameter substantially equal to the outer diameter of the tube 3, and the pressing surface 10 a is a side peripheral surface orthogonal to the axis P.

  The internal screw 11 for retaining has the same pitch in the direction of the axis P as that of the female screw 8 on the inner peripheral surface side of the nut central portion 2T facing the enlarged diameter straight portion 12 (that is, the same pitch as that of the male screw 5). And it is formed with the triangular screw which presents the screw thread y of the cross-sectional shape where a point is sharp. The tip of the thread y is set to have a diameter slightly smaller than the diameter of the outer peripheral surface 12a of the enlarged straight portion 12. Accordingly, when the male screw 5 and the female screw 8 are screwed together and the union nut 2 is rotated and operated to be screwed, the outer peripheral surface 12a of the enlarged diameter straight portion 12 is also screwed by the retaining inner screw 11. A state in which the screw thread y bites into the outer peripheral surface 12a or is strongly pressed in the radial direction without being damaged is obtained. Due to the action of the screw thread y pressing the enlarged diameter straight portion 12 over the long distance, it becomes possible to strongly resist the force that the enlarged diameter portion 3 </ b> A tries to escape from the inner cylinder portion 4.

  Next, in order to externally insert and insert the end of the tube 3 into the inner cylinder portion 4, the tube 3 is forcibly pushed in at room temperature to expand the diameter, or it is easily heated and expanded using a heat source. Then, the tube end 3t is moved as shown in FIG. 1 by pushing it in, or by enlarging the tube end in advance using a diameter expander (not shown) and then pushing it into the inner cylinder part 4. Insert it to the inside so as to reach the side wall 15. In the first embodiment, the enlarged diameter portion 3A that is externally fitted to the inner cylinder portion 4 has an enlarged diameter that is fitted to the outer peripheral surface 4a of the tapered tip portion 4A as shown in FIGS. It consists of the change area | region 9 and the diameter expansion straight part 12 externally fitted by the outer peripheral surface 4b of the straight cylinder part 4B.

  That is, as shown in FIGS. 1 and 2, the joint main body 1 is formed by tightening the union nut 2 by screwing the female screw portion 8 with the male screw portion 5 in a state in which the tube 3 is externally fitted to the inner cylinder portion 4. The small diameter side portion of the diameter expansion change region 9 is pressed in the direction of the axis P by the sealing peripheral edge 10 and the diameter expansion straight portion 12 is secured by the internal screw 11 for retaining. It is configured to be pressed in the radial direction. Note that the diameter of the fluid transfer path 3W of the tube 3 and the diameter of the fluid path 7 are set to be the same diameter in order to obtain a smooth fluid flow, but may be different from each other.

  In the first embodiment, the diameter-enlarged region 9 of the tube 3 is formed as a portion that is tapered at the tip and covers the cylindrical portion 4A. The diameter expansion region 9 is a state of a taper tube that gradually expands, and the circumferential edge 10 for sealing and the internal screw 11 for retaining are in a positional relationship apart from each other in the direction of the axis P, but the tip tapered tube As the angle of the outer peripheral surface 4a of the portion 4A with respect to the axis P becomes steeper, the distance in the axis P direction between the sealing peripheral edge 10 and the retaining inner screw 11 becomes closer. Further, the sealing peripheral edge 10 and the inner cylinder portion 4 are slightly separated from each other in the direction of the axis P (see FIG. 2 and the like). However, if the angle of the outer peripheral surface 4a becomes steep, the distance is increased. If it becomes loose, the separation distance is reduced.

  As shown in FIGS. 1 and 2, in a predetermined assembled state of the resin pipe joint A, the sealing peripheral edge 10 has the small diameter side end portion of the diameter expansion change region 9 of the tube 3 in the axis P direction. Since the pressing is performed, the small diameter side end of the outer peripheral surface 4a of the diameter expansion change region 9 and the inner peripheral surface of the tube 3 in contact with the portion are strongly pressed to form the seal portion S. The tube 3 and the joint main body 1 are well sealed by the seal portion S at the tip of the inner tube portion 4 without any fluid such as cleaning liquid or chemical solution entering between the inner tube portion 4 and the enlarged diameter portion 3A. Yes.

  The diameter-enlarging straight portion 12 of the diameter-enlarging portion 3A that is press-fitted externally to the inner cylinder portion 4 acts in the radial direction with a retaining inner screw 11 that acts as if it is threaded on the outer peripheral surface 12a. Is pressed. Therefore, the retaining means N in which the movement in the direction in which the diameter-enlarged portion 3A is pulled out from the inner cylinder portion 4 in the direction of the axis P is firmly restricted is configured, thereby realizing an excellent pull-out resistance. As a result, the flare-type resin pipe joint A composed of the joint body 1 and the union nut 2 can be easily assembled by a nut operation in a state where the tube is mounted on the inner cylinder portion, and has excellent assemblability. Thus, it is realized as an improved one that can achieve both excellent sealing performance by the seal portion S and excellent pulling-out resistance by the retaining means N.

  In addition, since the retaining inner screw 11 and the female screw 8 are at the same pitch, the retaining inner screw 11 is screwed into the enlarged diameter straight portion 12 as the union nut 2 is turned in the tightening direction. The pressing action is smoothly performed, and the unscrewing action of the retaining inner screw 11 from the enlarged diameter straight portion 12 during the turning operation in the loosening direction of the union nut 2 is also smoothly performed. Due to the provision of N, there is an advantage that the turning operation of the union nut 2 hardly becomes heavy or can be reduced as much as possible. In addition, by adopting the sharp thread y, the tube 3 and the union nut 2 are made of the same fluororesin, but they can be pressed in the radial direction while forming a screw on the enlarged diameter straight portion 12, and have a strong pulling resistance. There are also benefits to be gained.

[Example 2]
The resin pipe joint A according to the second embodiment is the same as the resin pipe joint A according to the first embodiment, except that a male screw that can be screwed into the retaining internal thread 11 is formed on the outer peripheral surface 12a of the diameter-enlarging straight portion 12 in advance. The same. That is, as shown in FIG. 3, the end portion of the tube 3 is expanded in diameter so as to follow the outer shape of the inner cylinder portion 4, and the pre-expanded outer peripheral surface 13a of the tube end 13 is used for retaining. A male screw 18 that is screwed into the inner screw 11 is formed. For example, the male screw 18 is formed as an extremely shallow screw valley of the screw depth in accordance with the retaining internal screw 11 shown in FIGS.

  Then, the tube end 13 on which the male screw 18 is formed is forcibly inserted into the inner cylinder portion 4 and press-fitted. After that, the same as in the case of the first embodiment, but since the male screw 18 has already been formed on the outer peripheral surface 12a of the diameter-enlarging straight portion 12, the inner screw for retaining is prevented when the union nut 2 is rotated. Since the operation of cutting the enlarged diameter straight portion 12 with the screw 11 is unnecessary, the turning force of the union nut 2 is smaller than that of the first embodiment. In other words, the union nut has an advantage that it can be turned lightly while obtaining an effective pull-out force.

[Another Example]
The sealing pressing portion 10 has an intermittent circumferential edge divided into a plurality in the circumferential direction, a cross-sectional shape such as an angle of 80 degrees or 100 degrees, and other than 90 degrees (right angle) shown in FIG. An angle is also acceptable. The resin material of the union nut 2 is set to have a mechanical strength superior to that of the resin material of the tube 3, and the internal screw 11 for retaining the union nut 2 is screwed to the joint body 1 by the enlarged straight portion 12. It can be clearly screwed or pressed more strongly in the radial direction.

  As the synthetic resin, various resins such as PEEK (polyetheretherketone) and PP (polypropylene) can be used in addition to the fluororesin. Further, as the fluororesin, various types such as PTFE, PFA, PVDF, ETFE and the like are possible.

Sectional drawing which shows the structure of the resin pipe joint by Example 1 FIG. 1 is an enlarged sectional view showing the main part of FIG. Operational diagram showing tube forming and mounting in the resin pipe joint of Example 2

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Joint main body 2 Union nut 3 Tube 3A Diameter expansion part 4 Inner cylinder part 4A Tip-cone cylinder part 4B Straight body cylinder part 5 Male thread part 8 Female thread part 9 Diameter expansion change area 10 Sealing press part 11 Internal screw for retaining 12 Expanded straight portion 12a Outer peripheral surface 18 Male thread P Shaft center y Thread

Claims (6)

Synthetic resin joint body provided with an inner cylindrical portion that can be fitted to the end by expanding the end of the synthetic resin tube, and a male screw, and
A female screw that can be screwed into the male screw, a seal pressing portion that can act on a small-diameter side portion of a diameter-enlargement change region in a diameter-enlarged portion that is externally fitted to the inner tube portion of the tube, and a diameter in the diameter-enlarged portion A union nut made of a synthetic resin provided with an internal screw for retaining that can act on an enlarged straight portion surrounded by a certain straight barrel portion;
By unscrewing the union nut in the axial direction of the joint body by screwing the female screw with the male screw in a state where the tube is fitted on the inner tube portion and the enlarged diameter portion is formed. The small diameter side portion of the diameter expansion changing region is pressed in the axial direction by the sealing pressing portion, and the diameter increasing straight portion is pressed in the radial direction by the retaining internal screw. Resin pipe fittings.   The resin pipe joint according to claim 1, wherein the retaining inner screw is formed of a screw having a sharp thread.   The resin pipe joint according to claim 1 or 2, wherein the retaining inner screw and the female screw are set at the same pitch.   The resin pipe joint according to claim 3, wherein a male screw capable of being screwed to the internal screw for retaining is formed in advance on an outer peripheral surface of the diameter-enlarging straight portion.   The inner tube portion is formed to have a tip tapered tube portion that gradually expands the diameter of the tube, and the straight body tube portion that is formed on the large diameter side of the tip tapered tube portion. The resin pipe joint according to any one of claims 1 to 4, wherein a diameter-enlargement change region of the tube is a portion that covers the cylindrical portion with the tip tapered.   The resin pipe joint according to any one of claims 1 to 5, wherein the joint body and the union nut are both made of a fluororesin.

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