JP2010038269A - 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 female screw 5 formed outward of the diameter thereof, and the fluororesin union nut 2 having a cylindrical protrusion 13 capable of entering into a clearance m between the inner cylinder portion 4 and the female screw 5, a male screw 8 formed on the outer periphery thereof, a seal thrusting portion 10 operable on a small-diameter side portion of a diameter-enlarged change region 9 on a tube diameter-enlarged portion 3A, and an anti-come-off inclined inner peripheral face 11 formed on the cylindrical protrusion 13 and operable on a large-diameter side end portion of the diameter-enlarged change region 9. As the union nut 2 is threaded, the large-diameter side end portion of the diameter-enlarged change region 9 is thrust by the anti-come-off inclined inner peripheral face 11 and the small-diameter side portion of the diameter-enlarged change region 9 is thrust by the seal thrusting portion 10. <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.

According to the first aspect of the present invention, in the resin pipe joint, the inner cylindrical portion 4 that can be fitted and fitted by expanding the diameter of the end portion of the synthetic resin tube 3 is the same as the axis P of the inner cylindrical portion 4. A synthetic resin joint body 1 having an axial center and an internal thread 5 formed in the radially outward direction of the inner cylinder portion 4; and
A cylindrical projection 13 that can enter a radial gap m between the inner cylindrical portion 4 and the female screw 5; a male screw 8 that is formed on the outer peripheral portion of the cylindrical projection 13 and can be screwed into the female screw 5; The pressing portion 10 for sealing that can act on the small-diameter side portion of the expanded diameter changing region 9 in the expanded diameter portion 3 </ b> A that is fitted on the inner cylindrical portion 4 of the tube 3, and the expanded diameter changing region 9 with respect to the axis P A retaining inclined inner peripheral surface 11 formed on the cylindrical projection 13 in a state where it can act on the large diameter side end portion of the diameter expansion change region 9 by tilting at a gentle angle in the same direction. Having a union nut 2 made of synthetic resin,
In the state where the tube 3 is externally fitted to the inner cylinder portion 4 and the enlarged diameter portion 3A is formed, the male screw 8 is screwed into the female screw 5 in the axial center P direction of the union nut 2. The large diameter side end portion of the diameter expansion change region 9 is pressed in the direction of the axis P by the retaining inclined inner peripheral surface 11 and the small diameter side portion of the diameter expansion change region 9 is The seal pressing portion 10 is configured to be pressed in the direction of the axis P.

  According to a second aspect of the present invention, in the resin pipe joint according to the first aspect, the inner cylindrical portion 4 includes a tip tapered tube portion 4A for gradually expanding the diameter of the tube 3, and the tip tapered tube. A straight barrel portion 4B formed on the large diameter side of the portion 4A, and a diameter-enlarged change region 9 of the tube 3 is a portion that covers the tip portion of the tubular portion 4A. It is characterized by this.

  The invention according to claim 3 is the resin pipe joint according to claim 1 or 2, wherein a guide inclined inner peripheral surface 15 is formed on the large diameter side of the retaining inclined inner peripheral surface 11, An inclination angle of the guide inclined inner peripheral surface 15 with respect to the axis P is set in the same direction as that of the retaining inclined inner peripheral surface 11 and is loose. .

  The invention according to claim 4 is the resin pipe joint according to any one of claims 1 to 3, 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. Then, the screwed inclined inner peripheral surface for contact is brought into contact, so that the tube enlarged portion is pressed in the axial direction while being strongly pressed in the radial direction, and the enlarged diameter portion is the inner cylindrical portion in the axial direction. The function of effectively restricting the movement in the direction of exiting is generated. 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. Further, in the joint body, the insertion portion of the tube into the inner tube portion, that is, the expanded diameter portion, and the female screw that is the connecting portion of the union nut can be arranged in a state of overlapping in the radial direction. There is also an advantage that the axial length can be made compact while the structure in which the joint body is screwed and connected.

  According to the second aspect of the present invention, it is easy to perform external fitting on the inner cylinder part by expanding the tube diameter using the tapered part at the tip, and the effect of the pressing part for the seal on the diameter change region. Since the location and the location where the sloped inner peripheral surface for retaining is applied to the area where the diameter is changed are separated from each other in the axial direction, each of the sealing function and the retaining function can be clearly demonstrated easily. There exists an advantage which becomes possible [strengthening the said effect by invention of claim | item 1].

  According to the invention of claim 3, the guide inclined inner peripheral surface formed subsequent to the retaining inclined inner peripheral surface causes some dimensional variation, product error, or assembly to the enlarged diameter portion or the cylindrical protrusion. Even if an error has occurred, the diameter-enlarging straight part can be introduced inside the cylindrical projection, and the resin that ensures that the function of retaining the enlarged-diameter part by the inclined inner peripheral surface for retaining is surely exhibited. Pipe fittings can be provided.

  According to the invention of claim 4, since both the joint body and the union nut are made of a fluorine-based resin having excellent 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. FIG. 1 is a cross-sectional view of a resin pipe joint according to Example 1, and FIG. 2 is an enlarged cross-sectional view of a main part of the resin pipe joint of FIG. In the present specification, the “inner back side” is a definition of the back side in the direction of the axis P from the reference part (or part), and the axis in the object (eg, joint body 1). The central position in the direction of the heart P is not necessarily the deepest.

[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 includes an inner cylinder portion 4 that can be externally fitted by expanding the end portion of the tube 3, and an axis that is the same as the axis P of the inner cylinder portion 4. A cover cylinder portion 6 having P and formed outside the inner cylinder portion 4, a female screw 5 as an internal thread formed on the inner peripheral surface of the cover cylinder portion 6, and a cylinder having an axis P It is formed in a cylindrical member provided with a spatial fluid path 7. The inner cylinder part 4 has a straight shape having a tip tapered cylinder part 4A for gradually expanding the diameter of the tube 3 and a straight cylinder part 4B formed on the large diameter side of the tip tapered cylinder part 4A. It is structured as a thing.

  Between the radial direction of the inner cylinder part 4 and the cover cylinder part 6, it is the surrounding groove | channel m which penetrates deeply in the axial center P direction, The inner peripheral surface is the outer peripheral surface 4b of the straight cylinder part 4B, The outer periphery The surface is the inner peripheral surface of the cover tube portion 6, that is, the female screw 5. 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. Further, the taper inner peripheral surface 6b can function as a guide surface for causing the tube 3 to smoothly enter the peripheral groove m.

  As shown in FIGS. 1 and 2, the union nut 2 includes a male screw 8, a sealing peripheral edge (an example of a sealing pressing portion) 10, a retaining inclined inner peripheral surface 11, a cylindrical protrusion 13, And a guide tube portion 14. The male screw 8 is formed on the outer peripheral surface of the cylindrical protrusion 13 and is formed so as to be screwable with the female screw 5 of the joint body. The cylindrical protrusion 13 can enter and retract into the circumferential groove m in a state where the male screw 8 formed on the outer peripheral portion thereof is screwed with the female screw 5 and on the outer diameter side of the enlarged diameter straight portion 12 (described later). .

  In addition, the inner peripheral surface of the cylindrical protrusion 13 is tapered with respect to the axis P, and the inner protrusion on the inner back side is inclined at an inclination angle β that is less than the inclination angle α of the outer peripheral surface 4a of the cylindrical portion 4A. It is formed on the peripheral surface 11 and a guide inclined inner peripheral surface 15 on the distal end side formed continuously on the large diameter side. The inclination angle γ with respect to the axis P of the guide inclined inner peripheral surface 15 is set to the same direction as the inclination angle β of the retaining inclined inner peripheral surface 11 and a looser angle than that. That is, between the three of the inclination angle α of the tip tapered cylindrical portion 4A, the inclination angle β of the retaining inclined inner peripheral surface 11, and the inclination angle γ of the guiding inclined inner peripheral surface 15, α > Β> γ.

  The retaining inner peripheral surface 11 is inclined with respect to the axis P at the large-diameter side end of the diameter expansion region 9 by inclining at an inclination angle of the diameter expansion region 9, that is, in the same direction as α and at a gentle angle β. It is formed in the cylindrical protrusion 13 so that it can act on the part. That is, it is possible to press the bending displacement portion at the boundary between the enlarged diameter changing region 9 and the enlarged diameter straight portion 12 in the axial center P direction by the retaining inclined inner peripheral surface 11. Note that auxiliary lines for indicating the angles β and γ are indicated by dashed lines in FIGS.

  The pressing portion 10 for sealing can act on the small diameter side portion of the diameter expansion change region 9 in the diameter expansion portion 3 </ b> A fitted on the inner cylinder portion 4 of the tube 3, and the inner diameter thereof is substantially equal to the outer diameter of the tube 3. The pressing surface 10a which is equal and is a side peripheral surface orthogonal to the axis P is provided. The guide cylinder portion 14 is formed subsequent to the sealing peripheral edge 10 so as to enclose the tube 3 over a predetermined length in the axis P direction. 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.

  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 firmly to reach the depth of the circumferential groove m so as to be in a press-fitted state. As shown in FIGS. 1 and 2, the enlarged-diameter portion 3A that is externally fitted to the inner cylinder portion 4 includes an enlarged-diameter changing region 9 that is fitted on the outer peripheral surface 4a of the cylindrical portion 4A. It consists of the diameter-expanded straight part 12 fitted on the outer peripheral surface 4b of the barrel part 4B.

  As shown in FIGS. 1 and 2, the joint main body is formed by tightening the union nut 2 by screwing the male screw portion 8 with the female screw portion 5 in a state in which the tube 3 is externally fitted to the inner cylinder portion 4. 1 is larger than the diameter of the inner cylinder portion 4 at the boundary between the enlarged diameter changing region 9 and the enlarged diameter straight portion 12, that is, at the larger diameter side end portion of the enlarged diameter changing region 9. This portion is pressed by the retaining peripheral edge 11 in the direction of the axis P. In addition, the small diameter side end portion (an example of the small diameter side portion) of the diameter expansion change region 9 is pressed in the axial center P direction by the sealing peripheral edge 10.

  In this case, the diameter-enlargement change 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 change region 9 is a state of a tapered tube that gradually expands, and the sealing peripheral edge 10 and the retaining inclined inner peripheral surface 11 are in a positional relationship adjacent to each other in the axis P 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.

  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.

  And the large-diameter side end portion of the expanded diameter changing region 9 that is also the base portion of the expanded diameter straight portion 12 of the expanded diameter portion 3A that is press-fitted to the inner cylinder portion 4 is a retaining inclined inner peripheral surface. 11 is pressed in the direction of the axis P, and acts so as to be pressed in the direction of the axis P while being strongly suppressed in the radial direction by the inclined component force. As a result, the root portion of the enlarged diameter straight portion 12 that is originally press-fitted and fitted into the straight cylinder portion 4B is pushed in both the radial direction and the axial center P direction by the retaining inclined inner peripheral surface 11 to expand the diameter. The retaining means N is configured to firmly restrict the movement of the portion 3A in the direction of coming out of the inner cylinder portion 4 in the direction of the axis P, thereby realizing an excellent pull-out resistance.

  In addition, since the internal thread 5 is formed in the joint body 1 and the male thread 8 is formed in the union nut 2 and screwed together, that is, the union nut 2 is embedded in the joint body 1, the retaining inclined inner peripheral surface 11 can strongly resist the reaction force that strongly expands the root portion of the cylindrical protrusion 13 outwardly in the radial direction due to the strong pressing of the enlarged diameter portion 3A in the radial direction. Therefore, the pull-out force is effectively exhibited, and it is possible to contribute to making the retaining function for the enlarged diameter portion 3A by the retaining means N appear.

  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 has been realized as an improved structure that can achieve both excellent sealing performance by the seal portion S and excellent pull-out resistance by the retaining means N. Further, due to the presence of the inclined inner peripheral surface 15 for the guide, even if there is some dimensional variation, product error, or assembly error in the enlarged diameter portion 3A or the cylindrical projection 13, the enlarged diameter straight portion 12 is made to be the cylindrical projection. 13, the function of the retaining means N is surely exhibited.

[Another Example]
The sealing pressing portion 10 and the retaining pressing portion 11 are shown in FIG. 2 and the like, such as an intermittent circumferential edge divided into a plurality in the circumferential direction, and a cross-sectional shape with a corner angle of 80 degrees or 100 degrees. An angle other than 90 degrees (right angle) may be used. Although illustration is omitted, the inner peripheral surface of the cylindrical protrusion 13 has a guide straight body inner peripheral surface having a diameter larger than the outer diameter of the enlarged outer straight portion 12 and a constant diameter, and a retaining inclined inner peripheral surface 11. It is good also as composition which consists of. Moreover, the inner cylinder part 4 is good also as a thing of a cross-sectional mountain shape so that the diameter of the inner back side of the straight cylinder part 4B may become thin.

  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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Joint main body 2 Union nut 3 Tube 3A Expanded diameter part 4 Inner cylinder part 4A Tip-constricted cylinder part 4B Straight barrel part 5 Female thread part 8 Male thread part 9 Expansion diameter change area 10 Sealing pressing part 11 In the retaining inclination Peripheral surface 13 Cylindrical protrusion 15 Inclined inner peripheral surface for guide P Axis center m Radial gap (circumferential groove)

Claims (4)

An inner tube portion that can be fitted and fitted with an enlarged end portion of the synthetic resin tube, and an axial center that is the same as the shaft center of the inner tube portion, is formed in the radially outward direction of the inner tube portion. A synthetic resin joint body comprising a female screw, and
A cylindrical protrusion capable of entering a radial gap between the inner cylindrical portion and the female screw, a male screw formed on an outer peripheral portion of the cylindrical protrusion and threadably engageable with the female screw, and the inner cylindrical portion of the tube. The sealing pressing portion that can act on the small diameter side portion of the expanded diameter change region in the expanded diameter portion to be externally fitted, and the expansion by tilting at a loose angle in the same direction as the expanded diameter change region with respect to the axis. A sloped inner peripheral surface for retaining formed on the cylindrical projection in a state where it can act on the large-diameter side end portion of the diameter change region, and a union nut made of a synthetic resin,
The expansion of the union nut in the axial direction by screwing the male screw into the female screw in a state where the tube is externally fitted to the inner cylindrical portion to form the enlarged diameter portion. The large-diameter side end portion of the diameter change region is pressed in the axial direction by the retaining inclined inner peripheral surface, and the small-diameter side portion of the diameter expansion change region is pressed by the seal pressing portion in the axial direction. Resin pipe joint configured to be pressed.   The inner tube portion is formed to have a tip-constricted tube portion that gradually expands the diameter of the tube, and a straight body tube portion that is formed following the large-diameter side of the tip-contained tube portion. 2. The resin pipe joint according to claim 1, wherein the diameter expansion change region of the tube is a portion that is constricted at the distal end and covers the cylindrical portion.   A guide inclined inner peripheral surface is formed on the large diameter side of the retaining inclined inner peripheral surface, and an inclination angle of the guide inclined inner peripheral surface with respect to the axis is the retaining inclined inner peripheral surface. The resin pipe joint according to claim 1 or 2, wherein the resin pipe joint is set to be loose in the same direction as the one.   The resin pipe joint according to any one of claims 1 to 3, wherein the joint body and the union nut are both made of a fluororesin.

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