JP4885202B2 - Resin pipe fitting - Google Patents

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 fitting cylinder (5) of the joint body (4), or as shown in FIG. Is expanded to fit into the fitting cylinder (5). Then, the union nut (6) fitted in the tube in advance is screwed into the joint body, and tightened to forcibly move in the axial direction of the joint body (4), thereby expanding the tube (1). The diameter root portion (2a) is strongly pressed in the axial direction by the edge portion (6a) to seal between the tube (1) and the fitting tube (5).

  A resin pipe joint disclosed in FIGS. 8 and 9 of Patent Document 2 is also known as the same structure as described above. Further, as disclosed in FIG. 5 of Patent Document 2 and Patent Document 3, a tube end that is externally expanded to the inner ring is fitted into a fitting cylinder of a joint body, and the tube is tightened by a union nut. There is also a resin pipe joint having a structure in which a diameter-enlarged portion to the inner ring is pressed and sealed. In any case, the tube end is expanded (flared) and sealed with a union nut. In the former structure in which the end of the tube is fitted outside the fitting cylinder part and is fastened with a nut, there is a merit that a pipe joint can be economically configured with two parts of a joint body and a union nut. With the structure, it is possible to reliably avoid leakage, obtain stable performance, and have excellent reliability.

  By the way, in actual construction of resin pipe joints having various excellent merits as described above, there is a chronic improvement item that it is difficult to understand the end point of union nut tightening. Originally, in the joint made of resin, due to the characteristics of the material, the tightening torque gradually increases with respect to the union nut turning operation, so the feeling of closing due to the sudden increase in the tightening torque like a metal material is poor, It is difficult to understand the end of tightening sensuously. Insufficient tightening may cause leakage, and excessive tightening may damage the joint. Since it is made of resin, these disadvantages are likely to occur. Therefore, it is necessary to correctly complete the tightening of the union nut.

Therefore, in Patent Document 3, a projecting piece (15) projecting in the axial direction in a cantilevered state on the joint body (1), and a protrusion formed on the end of the union nut (2) in the axial direction ( When the union nut (2) is about to end tightening, it comes into close contact with each other in the circumferential direction and comes into contact with it. A technique is disclosed that makes it possible to know that the person is approaching.
Noto 3041899 gazette Japanese Patent Laid-Open No. 7-27274 Japanese Patent Laid-Open No. 11-230463

  By listening to the struck sound, it is possible to confirm the end of the tightening state by operating the union nut, even if the pipe joint portion is not visible, and a certain effect can be obtained. However, the actual piping work site is rarely in a quiet situation, and it is in a certain level of noise conditions, such as working in a factory that is in operation or other work and construction work being done together Often done. Therefore, in such a noise situation, the operator can not hear the sound that the resin protrusion can play, so there is an incomplete feeling as a means of notifying the end of union nut tightening, and further improvement There was room left for.

  In view of the above circumstances, the object of the present invention is to make it possible to confirm that the union nut has been tightened or close to it regardless of the noise situation at the work site. It is in the point which provides the resin pipe joint improved so that it may be excellent in property.

The invention according to claim 1 is a synthetic resin joint body 1 comprising a fitting tube 4 that can be fitted and mounted by expanding the diameter of an end of the synthetic resin tube 3, and a male screw 5, and
A union nut 2 made of a synthetic resin including a female screw 8 that can be screwed into the male screw 5 and a sealing pressing portion 10 that can act on a diameter expansion change region 9 in the diameter expansion portion 3A of the tube 3;
The union nut 2 is screwed in the axial direction P of the joint body 1 by screwing the female screw 8 into the male screw 5 in a state in which the tube 3 is fitted and attached to the fitting cylinder 4. In the resin pipe joint configured such that the expanded diameter change region 9 is pressed in the axial center P direction by the sealing pressing portion 10 to form the sealing portion S.
A first rough peripheral surface 24 is formed on the peripheral surface of the end portion of the union nut 2 in the axial center P direction by continuously forming fine irregularities in the circumferential direction by a predetermined amount. End of screwing of the union nut 2 by providing a second rough circumferential surface 20 formed by continuously forming a predetermined amount of fine irregularities in the circumferential direction and the pressing portion 10 for sealing presses the diameter expansion change region 9 Along with the tightening rotation from near the front, there is a sliding fitting portion 26 in which the first rough circumferential surface 24 and the second rough circumferential surface 20 are forcibly fitted to each other by their one deflection displacement. It is characterized by being comprised.

  The invention according to claim 2 is the resin pipe joint according to claim 1, wherein both the first and second rough circumferential surfaces 24, 20 are formed by knurling by knurling. It is.

  According to a third aspect of the present invention, in the resin pipe joint according to the first or second aspect, the first rough circumferential surface 24 is formed on an inner circumferential surface of the female thread forming side end portion of the union nut 2, and the second The rough circumferential surface 20 is formed on the outer circumferential surface of the flange 1 </ b> A of the joint body 1.

  The invention according to claim 4 is the resin pipe joint according to claim 3, wherein the female thread forming side end portion on which the first rough circumferential surface 24 is formed is divided into a plurality in the circumferential direction. To do.

  The invention according to claim 5 is characterized in that: the joint body 1 and the union nut 2 are made of a fluororesin.

  According to the first aspect of the present invention, the sliding fitting portion in which the first rough peripheral surface and the second rough peripheral surface are forcedly engaged by one bending is described in detail in the section of the embodiment. Therefore, it is possible to recognize that the tightening end state has been approached or the tightening end state has been reached by both the sliding noise and the torque increase (torque fluctuation). That is, it is possible to recognize the tightening end state or the like with two kinds of senses, that is, a sound that can be heard from the ear and a torque fluctuation that is felt at the fingertip. As a result, the resin is improved so that it can be confirmed that the union nut has been tightened or is close to it regardless of the noise situation at the work site, and it is excellent in assembly workability and handling. Pipe fittings can be provided.

  According to the invention of claim 2, if it is a means for forming fine irregularities by knurling which is a general technique, a practical resin pipe joint that is inexpensive and suitable for mass production can be constructed. Further, as in claim 3, if the first rough circumferential surface on the outer fitting side is formed on the union nut covering the joint body, and the second rough circumferential surface on the inner view side is provided on the joint body, the structure The sliding fitting part can be configured easily and rationally. Furthermore, if the male screw forming side end is divided into a plurality of portions in the circumferential direction as in claim 4, a plurality of first rough peripheral surfaces that are easily deflected and displaced are provided, and the resin tube that functions well in the recognition of the tightening end state. A joint can be provided.

  According to the invention of claim 5, the joint body and the union nut are formed of a fluorine resin having characteristics excellent in chemical resistance and heat resistance, and 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.

  According to the invention of claim 6, although the details will be described in the section of the embodiment, the union screwing of the union nut is terminated by visual observation of the situation where the tip of the protruding cover is located within the range of the axial width of the outer peripheral flange. That is, the tightening end state can be recognized. That is, with the function of the tightening end recognizing means, it is possible to know the tightening end state only by looking at the pipe joint while turning the union nut. As a result, it is possible to confirm that the union nut is in the tightened state even at work sites under noisy conditions, and to provide a resin pipe joint that is improved so that it can be assembled and handled easily. can do.

  Embodiments of the present invention will be described below with reference to the drawings. 1, 2 and 4 are a cross-sectional view, an axial direction view and a plan view showing the resin pipe joint in the tightened state, FIG. 3 is a cross-sectional view showing the resin pipe joint in a state before the tightening is finished, and FIG. It is a top view which shows the resin pipe joint after fastening.

[Example 1]
As shown in FIG. 1, FIG. 2 and FIG. 4, the resin pipe joint A according to the first embodiment is made of a tube 3 made of fluororesin (an example of a synthetic resin typified by PFA, PTFE, etc.) and a fluid such as a pump and a valve. It is connected to equipment and tubes of different diameters or the same diameter, and is a joint body 1 made of fluororesin (an example of a synthetic resin represented by PFA, PTFE, etc.) and a fluororesin (represented by PFA, PTFE, etc.) An example of the synthetic resin is made up of two parts: a union nut 2 made of the resin. FIG. 1 shows a tightening end state (assembled state) in which the union nut 2 is tightened by a predetermined amount.

  As shown in FIGS. 1, 2, and 4, the joint body 1 includes an inner cylinder 4 (an example of a fitting cylinder) 4 that can be externally fitted by expanding the end of the tube 3, and an inner cylinder 4. A cover tube portion 6 having a circumferential groove m extending in the axis P direction so as to allow the tip of the tube 3 whose diameter is expanded to the outer peripheral side of the inner back side portion thereof, a male screw 5 formed of a trapezoidal screw, A cylindrical member having a cylindrical space-like fluid path 7 having an axis P is formed. The inner cylinder 4 has a tapered straight shape having a tapered tip portion 4A for gradually expanding the diameter of the tube 3 and a straight barrel portion 4B formed on the large diameter side of the tapered tip portion 4A. It is structured as a thing.

  In the circumferential groove m, the outer peripheral surface that is the inner peripheral surface of the diameter is the outer peripheral surface 4b of the straight barrel portion 4B, and the outer peripheral surface that is the outer peripheral surface of the diameter is the inner peripheral surface 6a of the cover cylindrical portion 6. . An outer peripheral flange 1A is formed at a position away from the inner peripheral surface 21 of the circumferential groove m in the axial center P direction by a predetermined length, and the outer peripheral surface of the end portion of the cover tube portion 6 from the substantially root portion of the outer peripheral flange 1A. A male screw 5 is formed over the entire area. The tip surface of the inner cylinder 4 is provided with a reverse taper angle closer to the inner back side (back side in the direction of the axis P) toward the inner side in the radial direction, that is, a cut surface 16 having a larger diameter toward the tip is formed. The shape of the liquid pool peripheral portion 17 resulting from the displacement of the inner peripheral surface of the tube 3 toward the enlarged diameter portion (flare portion) is defined as the inner peripheral side expanded shape, and the fluid is stored in the liquid pool peripheral portion 17. It is hard to be stagnant.

  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, on the side opposite to the male screw 5 in the axial center P direction of the flange 1A, an operation hexagonal nut portion 23 having a constant width in the axial center P direction, and a pipe portion (connecting portion) 25 (FIG. 3). 5) is formed.

  As shown in FIGS. 1, 2, and 4, a fitting cover 1 has a press-fit outer fit of a protruding cover 19 (described later) formed at the end (axis end) of the union nut 2 in the axis P direction. An outer peripheral flange 1 </ b> A that allows the covering by is formed. The outer peripheral flange 1A has a diameter larger than that of the hexagonal nut portion 23 and the male screw 5, has a sufficiently large thickness (width) in the direction of the axis P, and is rich in strength and rigidity. The outer peripheral surface of the outer peripheral flange 1A is formed on an uneven outer peripheral surface 20 (an example of a second rough peripheral surface) formed by continuously forming a predetermined amount of fine unevenness in the circumferential direction. Specifically, the concave / convex outer peripheral surface 20 is configured by forming knurls by knurling on the outer peripheral surface of the outer peripheral flange 1A. As the knurled eye, a flat eye (straight pattern) is employed in Example 1, but a square eye (cross pattern) or a rhombus eye (diamond pattern) may be used.

  The union nut 2 includes an internal thread 8 that can be screwed into the external thread 5 and an expanded diameter change region 9 in the expanded diameter section 3A that is externally fitted to the inner cylinder 4 of the tube 3, as shown in FIGS. Peripheral edge for sealing (an example of a pressing portion for sealing) 10 that can act on the small-diameter side end portion, a retaining peripheral edge 11 that can act on the large-diameter side end portion of the diameter-enlarging change region 9, and the enlarged-diameter portion 3A, a presser inner peripheral portion 13 that can be externally fitted to a diameter-enlarging straight portion 12 that is surrounded by a straight barrel portion 4B having a constant diameter, and a tube 3 that has a predetermined length in the axis P direction following a sealing peripheral edge 10 A guide cylinder portion 14 is provided so as to surround the entire length.

  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 diameter of the circumferential edge 11 for retaining is larger than that of the outer peripheral surface 4b of the straight barrel portion 4B whose inner peripheral surface is the maximum diameter of the inner tube 4, and the diameter obtained by adding the wall thickness of the tube 3 That is, although it is set to a value smaller than the diameter of the presser inner peripheral portion 13, it may not be so (for example, a smaller diameter than the outer peripheral surface 4 b), and if it acts on the large diameter side portion of the diameter expansion change region 9. good. The pressing surface 11a of the retaining peripheral edge 11 is also a side peripheral surface orthogonal to the axis P.

  The presser inner peripheral portion 13 has no radial clearance between the presser inner peripheral portion 13 and the enlarged diameter straight portion 12 so that the enlarged diameter portion 3A is not rotated by tightening of the union nut 2. The retaining means N is configured to be set to a value that is press-fitted (press-fit externally fitted). This is because when the union nut 2 is tightened, the retaining peripheral edge 11 presses the enlarged diameter straight portion 12 in the axial direction so as to prevent the tube 3 from being pulled out. This is to prevent the portion 12 from escaping so as to swell outward in the radial direction, and to increase the pull-out force by cooperating with the peripheral edge 11 for retaining.

  As shown in FIGS. 1, 2 and 4, the female screw side end, which is the end of the union nut 2 in the axial center P direction, has an arcuate shape protruding in the axial center P direction from the outer peripheral flange 1A. A protruding cover 19 is formed that is press-fitted and can be covered in the radial direction. The protruding cover 19 has a shape in which a cylindrical axial center end (female screw forming side end) of the union nut 2 is divided into a plurality of parts in the circumferential direction, that is, a hook or the like that forms an arc shape when viewed in the axial center P direction. It has a bowl shape and is formed at eight locations at equal angles (45 degrees) with respect to the axis P.

  The outer diameter of the protruding cover 19 is the outer diameter of the union nut 2, and the inner diameter is set to be the same as or slightly smaller than the outer diameter of the outer peripheral flange 1A. The inner peripheral surface of each protruding cover 19 is formed on a concave / convex inner peripheral surface (an example of a first rough peripheral surface) 24 formed by continuously forming a predetermined amount of fine irregularities in the circumferential direction. Specifically, the concave / convex inner peripheral surface 24 is configured by forming knurls by knurling on the inner peripheral surface of the protruding cover 19. As the knurled eye, a flat eye (straight pattern) is employed in Example 1, but a square eye (cross pattern) or a rhombus eye (diamond pattern) may be used.

  A window 18 is formed between the protruding covers 19 and 19 adjacent to each other in the circumferential direction. In short, the window portion 18 is a portion where the projecting cover 19 is not provided and the nut end surface 2a is exposed over the entire radial direction. The nut end surface 2a is a stopper surface that can come into contact with the outer peripheral flange 1A in the axis P direction as the union nut 2 is screwed.

  Next, in order to externally insert the end of the tube 3 into the inner cylinder 4, the tube 3 is forcibly pushed in at room temperature to increase the diameter, or it is warmed using a heat source so as to be easily deformed by expansion. The tube end 3t is formed as a cover tube as shown in FIG. 1 by pushing it into the inner tube 4 after expanding the tube end in advance using a diameter expander (not shown). Insert until the end wall 15 of the portion 6 is located inward. As shown in FIG. 1, the diameter-enlarged portion 3A that is externally fitted to the inner cylinder 4 includes an enlarged-diameter changing region 9 that is externally fitted to the outer peripheral surface 4a of the tip-constricted cylindrical portion 4A, and a straight cylinder portion 4B. The enlarged diameter straight portion 12 is fitted on the outer peripheral surface 4b.

  That is, as shown in FIG. 1, in the axial center P direction of the joint body 1 by tightening the union nut 2 by screwing the female screw 8 with the male screw 5 in a state where the tube 3 is externally fitted to the inner cylinder 4. As a result of the screwing, the presser inner peripheral portion 13 is externally fitted to the enlarged diameter straight portion 12, and a portion having a larger diameter than the diameter of the inner cylinder 4 in the larger diameter side portion of the enlarged diameter changing region 9 is used for retaining. The peripheral edge 11 is pressed in the direction of the axis P, and the small diameter side portion of the diameter expansion change region 9 is set to be pressed in the direction of the axis P by the sealing peripheral edge 10. 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 this case, as described above, there is no gap in the radial direction between the presser inner peripheral portion 13 and the enlarged diameter straight portion 12, and the enlarged diameter straight portion 12 is provided between the straight barrel portion 4B and the presser inner peripheral portion 13. It is in the state where it is clamped. Moreover, in Example 1, the diameter-expansion change area | region 9 of the tube 3 is formed as a part which the front-end | tip narrows and covers 4 A of cylinder parts. The diameter expansion change region 9 is a state of a taper tube that gradually expands, and the sealing peripheral edge 10 and the retaining peripheral edge 11 are in a positional relationship apart from each other in the axis P direction, but the tip tapered tube As the angle of the outer peripheral surface 4a of the portion 4A with respect to the axial center P becomes steeper, the distance in the axial center P direction between the sealing peripheral edge 10 and the retaining peripheral edge 11 becomes closer. Further, the sealing peripheral edge 10 and the tip of the inner cylinder 4 are slightly separated from each other in the direction of the axis P, but if the angle of the outer peripheral surface 4a becomes steep, the separation distance is enlarged, and if it becomes loose, the separation distance. Is reduced.

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

  The diameter-enlarging straight part 12 of the diameter-enlarging part 3A that is press-fitted to the inner cylinder 4 is surrounded by the outer peripheral surface 4b of the straight cylinder part 4B and the presser inner peripheral part 13, and is first expanded and deformed. The retaining peripheral edge 11 is positioned so as to substantially bite into the enlarged diameter straight portion 12. This resists the pulling force acting on the enlarged diameter portion 3A due to the catch of the retaining peripheral edge 11 that pushes the large diameter side end portion of the enlarged diameter change region 9 so as to substantially bite into the enlarged diameter straight portion 12. In addition, the diameter-enlarged straight portion 12 can be expanded and deformed in the radial direction by the pulling force with the retaining peripheral edge 11 as a starting point. It also comes to be.

  If the diameter-enlarged portion 3A is displaced in the axial center P direction even a little, the seal point in the seal portion S may be shifted and the seal function may be uncertain, but this is prevented in advance. Accordingly, the retaining means N is configured in which the movement of the diameter-enlarged portion 3A in the direction of coming out of the inner cylinder 4 in the direction of the axis P is firmly restricted, 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 nut operation in a state where the tube is attached to the inner cylinder, and has excellent assemblability. It has been realized as an improved product that can achieve both excellent sealing performance by the seal portion S and excellent pull-out resistance by the retaining means N.

  In addition, after the pressing of the large-diameter side portion of the enlarged-diameter changing region 9 by the retaining peripheral edge 11 is started, the pressing of the small-diameter side portion of the enlarged-diameter changing region 9 by the sealing peripheral edge 10 is started. Depending on the setting, that is, the pressing time difference means, there are the following operations and effects. That is, when the union nut 2 is turned and tightened (screwed), the retaining peripheral edge 11 is first moved to the diameter expansion region 9 (specifically, the large diameter side portion of the diameter expansion region 9). At that time, the peripheral edge 10 for sealing has not yet reached the diameter expansion change region 9. As a result, only the retaining peripheral edge 11 pushes the large-diameter side portion of the expanded diameter change region 9, more specifically, the portion having a larger diameter than the straight barrel portion 4 </ b> B in the axial center P direction. The tightening operation causes an action to push the enlarged diameter straight portion 12 further into the inner side of the inner cylinder 4.

  The diameter-enlarging straight portion 12 that is press-fitted and fitted to the straight barrel portion 4B is also pressed against the inner circumference portion 13 of the presser, but when the pressure-contact force is relatively weak, the diameter-enlarging portion 3A is displaced to move the inner cylinder 4 In order to insert the tube into the joint body 1 more reliably, the expanded diameter straight portion 12 pushed in the direction of the axis P is moved in the direction of the axis P. Due to the difficulty, it is possible to obtain a favorable effect that the pressure contact force is further increased and the action of being firmly clamped is generated in an attempt to expand in the radial direction. When the pressure contact force is relatively strong, the diameter-enlarging straight portion 12 pushed in the direction of the axis P is not able to move in the direction of the axis P first, thereby causing a strong action to expand in the radial direction. The effect that the diameter-expanded straight portion 12 is held more firmly with the presser inner peripheral portion 13 is obtained.

  That is, in any case, when the sealing peripheral edge 10 is not pierced into the enlarged diameter portion 3A, the retaining peripheral edge 11 pushes the enlarged diameter portion 3A in the direction of the axis P, thereby causing the straight barrel portion 4B. The press-holding force of the enlarged diameter straight portion 12 by the presser inner peripheral portion 13 is enhanced. For example, the portion that is pressed by the retaining peripheral edge 11 in the enlarged diameter portion 3A flows to the outside of the diameter and the corner space formed by the pressing surface 11a and the presser inner peripheral portion 13 is buried. As described above, the pressing time difference means provides an effect of further improving both the pressure-contact holding force of the tube 3 with respect to the inner cylinder 4 and the pull-out resistance.

  Further, as shown in FIG. 1, the tube 3 is correctly formed by the circumferential groove m formed by the inner back side of the inner tube 4 and the cover tube portion 6 and the union nut 2 formed by a fluororesin that can be seen through. The indicator means B that can visually check whether or not it is inserted into the inner cylinder 4 may be configured. That is, the diameter-enlarged portion 3 </ b> A is visible and the diameter-enlarged end portion is visually observed on a line passing through the valley-shaped inner circumferential surface 22 until reaching the female screw 8 on the inner inner side of the presser inner circumferential portion 13. This is because it can be determined that the tube 3 is correctly fitted to the inner cylinder 4 if 3t is in a normal state invisible. If the poorly inserted state where the enlarged diameter portion 3A can be seen and the enlarged diameter end portion 3t can be seen, or the insufficiently inserted state where the enlarged diameter portion 3A itself cannot be seen, the insertion of the tube 3 has still reached the specified amount. In this case, an operation of further pushing the tube 3 is performed until the normal state can be visually confirmed.

  In the indicator means B, the union nut 2 is formed using a transparent or translucent (milky white or the like) fluororesin, and an object inside thereof can be visually confirmed. In particular, it is enlarged by seeing through only the portion where the thickness of the union nut 2 is small by visual observation on the inner back side of the presser inner peripheral portion 13 and through the valley-shaped inner peripheral surface 22 until reaching the female screw 8. The diameter portion 3A is relatively easily visible. On the other hand, the visibility of the enlarged diameter portion 3A is inferior at the part of the presser inner peripheral part 13 which is thicker than the part of the valley-shaped inner peripheral surface 22, and is difficult to see.

  And since the union nut 2 and the cover cylinder part 6 have overlapped in the part of the circumferential groove m in which the edge part of the tube 3 can enter, even if the joint main body 1 can also be seen through, thickness is a valley-shaped inner peripheral surface. In addition to being thicker than the portion 22, a change in the refractive index at the boundary surface due to the overlap of the male screw 5 and the female screw 8 is also added, so that it is impossible to visually recognize where the enlarged diameter end 3 t is located. In addition, when the joint body 1 is not transparent such as being colored, it is needless to say that the enlarged diameter portion 3A or the enlarged diameter end portion 3t is seen on the inner and inner side of the end wall 15 of the cover cylinder portion 6. I can't.

  Therefore, the union nut 2 was tightened by the function of the indicator means B whether or not a normal state in which the enlarged diameter portion 3A can be seen from the valley-shaped inner peripheral surface 22 and the enlarged diameter end portion 3t cannot be seen. A resin pipe joint A that can be visually confirmed in a later assembled state and that is convenient and excellent in usability can be provided.

  Further, the presence of the circumferential groove m and the cover cylinder portion 6 for constituting the indicator means B also provides an effect of functioning as an indicator when the tube 3 is inserted into the inner cylinder 4. That is, it can be confirmed whether or not the amount of insertion into the inner cylinder 4 by flaring the tube 3 is a predetermined amount. That is, it is sufficient that the end 3t as the enlarged diameter portion 3A inserted into the inner cylinder 4 is deeper than the end wall 15, and as a means for visually judging whether the tube 3 is assembled to the inner cylinder 4 or not. There is an advantage to function.

  In this resin pipe joint A, the end of tightening of the union nut 2 (or that the end is near) in the assembly work state in which the tube 3 is inserted and the union nut 2 is tightened and fixed is determined by sliding noise and torque fluctuation. A fastening end recognition means C that can be recognized by both of them is provided. As shown in FIGS. 1, 2 and 4, the tightening end recognition means C is formed on the concave / convex outer peripheral surface 20 of the outer peripheral flange 1A of the joint body 1 and the tip end side (the female screw 8 side end) of the union nut 2. The projection cover 19 is provided with a sliding fitting portion 26 that is forcibly fitted so that the concave and convex inner peripheral surface 24 is in a press-fitted state. The sliding fitting portion 26 is formed in the concave and convex portions as the seal peripheral edge 10 presses against the diameter change region 9 and the union nut 2 where the seal portion S is formed is tightened from near the end of screwing. The peripheral surface 24 and the concave / convex outer peripheral surface 20 are configured by providing a structure in which the concave / convex inner peripheral surface 24, that is, the projection cover 19 is forcedly fitted to each other by the bending displacement.

  In the resin pipe joint A of the first embodiment, when the distal end surface 19a of each protruding cover 19 is located at the approximate center of the width of the outer peripheral flange 1A, that is, the width in the axis P direction, the tightening completion state of the union nut 2 is completed. The union nut 2 having the projecting cover 19 and the joint body 1 having the outer peripheral flange 1A are formed so as to be related to each other (assembled state as the joint A). Is configured.

  The operation of the sliding fitting portion 26 will be described. When the union nut 2 is tightened by, for example, applying a tool to the hexagonal nut portion 2b, the union nut 2 is screwed as shown in FIG. The protruding cover 19 approaches the outer peripheral flange 1A. In the relative positional relationship between the joint body 1 and the union nut 2 shown in FIG. 3, the peripheral edges 10 and 11 have not yet reached the diameter expansion change region 9 of the tube 3. When the union nut 2 is continuously rotated in the tightening direction, the tip end portion of each projecting cover 19 is bent radially outwardly, is forcedly fitted to the outer peripheral flange 1A, and begins to be covered so as to overlap in the radial direction. When the union nut 2 is continuously rotated in the tightening direction and screwed, as shown in FIGS. 1 and 4, the front end surface 19a of each protruding cover 19 is centered in the width direction (axial center P direction) of the outer peripheral flange 1A. To position.

  When the protruding cover 19 is externally fitted to the outer peripheral flange 1A, the concave / convex inner peripheral surface 24 and the concave / convex outer peripheral surface 20 move relative to each other while sliding (while rubbing) and continuously generate a sliding sound. As a result, a torque increase, that is, a state in which a large amount of torque for rotating and operating the union nut 2 is required is brought about. In other words, the function of the sliding fitting portion 26 allows the operator to recognize that the tightening end state has been approached by both sound and torque increase (torque fluctuation), or that the tightening end state has been reached. Thus, the tightening end recognition means C is configured. Therefore, it is possible to recognize the tightening end state of the union nut 2 regardless of the presence or absence of noise in the work environment.

  As described above, in the first embodiment, when the front end surface 19a reaches the half of the width of the outer peripheral flange 1A, the seal portion S is formed and the tightening is completed. become. In this assembled state, the sealing function by the sealing peripheral edge 10 and the retaining function by the retaining peripheral edge 11 are set to be effectively exhibited. The above-described tightening end state can also be recognized by visual observation that the front end surface 19a of the protruding cover 19 is located at the center in the width direction of the outer peripheral flange 1A. It can also be recognized by the fingertip feeling that the tip surface 19a is on the concave / convex outer peripheral surface 20 of the outer peripheral flange 1A.

  Further, since there is a window 18 between the projecting covers 19 and 19 adjacent in the circumferential direction, how much the outer peripheral flange 1A of the projecting cover 19 overlaps, the tip end surface 1a is in the direction of the axis P of the outer peripheral flange 1A. There is an advantage that the overlapping state such as which part of the width or the distance in the axis P direction between the side peripheral surface 1a on the male screw side and the nut end surface 2a can be visually recognized from the window portion 18.

  Next, retightening of the resin pipe joint A will be described. The nut end surface 2a and the outer peripheral flange 1A come into contact with each other by a slight tightening operation of the union nut 2 from the screwing end state (tightening end state). It will be possible. That is, when the union nut 2 is further rotated in the tightening direction from the tightened end state (assembled state) shown in FIGS. 1, 2 and 4, as shown in FIG. 5, the nut end surface 2a is on the male screw side of the outer peripheral flange 1A. The side surface 1a of the outer peripheral flange 1A is brought into a tightening limit. At that time, the front end surface 19a of the protruding cover 19 is flush with the side surface 1c on the nut side of the outer peripheral flange 1A in the axis P direction (the same position as each other). It is set to become.

  When the final tightening state shown in FIG. 5 is reached, there is an advantage that damage to the pipe joint A such as screw jump of the male screw 5 and the female screw 8 and neck breakage can be prevented. That is, the resin pipe joint A according to the first embodiment is also configured to be able to be tightened to compensate for the looseness of the union nut 2 due to a change with time, and in this case, the front end surface 19a of the protruding cover 19 is the outer peripheral flange 1A. It can be recognized by visual observation that it is the same as the side peripheral surface 1c on the nut side or the feel of the fingertip, and these functions are also exhibited by the tightening end recognition means C.

[Another Example]
The uneven inner circumferential surface 24, that is, the number of the protruding covers 19, the protruding length in the direction of the axis P, or the length in the circumferential direction can be appropriately changed and set. And it is also possible to make the internal thread side end part of the union nut 2 into a cylinder shape, and to make the whole internal peripheral surface into the uneven | corrugated internal peripheral surface 24. The concave / convex outer peripheral surface 20 formed on the outer peripheral flange 1 </ b> A is formed on the entire circumference in the first embodiment, but may be intermittently formed in the circumferential direction.

  In addition, the present invention is applied to a joint having a structure in which a tube expanded portion is fitted in a fitting cylinder using an inner ring, that is, a resin pipe joint composed of a union nut, a joint body, and an inner ring. Also good. In addition, although illustration and detailed explanation are omitted, an outer peripheral flange having a concave / convex outer peripheral surface (second rough peripheral surface) is formed at the axial center end portion of the union nut, and the concave / convex inner portion forcibly fitted to the outer peripheral flange is formed. A resin pipe joint having a configuration in which a protruding cover that has a peripheral surface (first rough peripheral surface) and can be covered is formed on the joint body.

Sectional drawing which shows the structure of the resin pipe joint by Example 1 Plan view of the resin pipe joint of Fig. 1 (assembled state) The top view which shows the state just before the assembly | attachment of the resin pipe coupling of FIG. The top view which shows the completion state of the retightening of the resin pipe joint of FIG. Axial direction view showing the meshing state of the first and second rough circumferential surfaces

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Joint body 1A Outer flange 2 Union nut 3 Tube 3A Expanded diameter part 4 Fitting cylinder 5 Male thread 8 Female thread 9 Expanded diameter change area 10 Sealing pressing part 19 Protruding cover 20 Second rough surface 24 First rough surface C tightening End recognition means P shaft center S seal part

Claims (5)

A synthetic resin joint body comprising a fitting tube that can be fitted and mounted by expanding the end of the synthetic resin tube, and a male screw, and
A union nut made of a synthetic resin provided with a female screw that can be screwed into the male screw, and a sealing pressing portion that can act on a diameter expansion change region in the diameter expansion portion of the tube;
As the union nut is screwed in the axial direction of the joint main body by screwing the female screw with the male screw in a state where the tube is fitted and attached to the fitting cylinder, the diameter expansion change region is A resin pipe joint configured to be pressed in the axial direction by a pressing portion for sealing to form a sealing portion,
A first rough circumferential surface formed by continuously forming a predetermined amount of fine irregularities in the circumferential direction on the circumferential surface of the end portion in the axial direction of the union nut is provided, and the fine irregularities are provided on the circumferential surface of the outer circumferential portion of the joint body. A second rough peripheral surface formed continuously by a predetermined amount in the circumferential direction is provided, and the sealing pressing portion presses the diameter-change changing region, so that the union nut is tightened and rotated from near the end of screwing. Along with this, a resin pipe joint in which a sliding fitting portion is formed in which the first rough circumferential surface and the second rough circumferential surface are forcibly fitted to each other by one bending displacement thereof.   The resin pipe joint according to claim 1, wherein the first and second rough circumferential surfaces are both formed by knurling by knurling.   The said 1st rough surrounding surface is formed in the internal peripheral surface of the internal thread formation side edge part of the said union nut, The said 2nd rough peripheral surface is formed in the outer peripheral surface of the flange of the said joint main body. The resin pipe joint described.   The resin pipe joint according to claim 3, wherein the female screw forming side end portion on which the first rough circumferential surface is formed is divided into a plurality of portions in the circumferential direction.   The resin pipe joint according to any one of claims 1 to 4, wherein the joint body and the union nut are made of a fluororesin.

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