JP4790035B2 - Resin pipe fitting - Google Patents

Description

  The present invention is also suitable for piping of high-purity liquid and ultrapure water handled in manufacturing processes in various technical fields such as semiconductor manufacturing, medical / pharmaceutical manufacturing, food processing, chemical industry, etc., and includes pumps, valves, filters, etc. The present invention relates to a resin pipe joint used as a connecting means for a tube which is a fluid device 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. That is, it is a sound generating means that informs the operator of the tightening end state by sound.
Noto 3041899 gazette Japanese Patent Laid-Open No. 7-27274 Japanese Patent Laid-Open No. 11-230463

  Even if the pipe joint portion is not visible, the sound generating means enables confirmation by the sound recognition of the tightening end state by the union nut operation, and a certain effect can be obtained. However, the actual plumbing work site is rarely in a quiet situation, and it is performed under some noise conditions, such as working in a factory that is in operation or other work or construction being done together. It is almost that. Therefore, it is often difficult for an operator to hear and recognize the beeping sound of the resin protruding piece, which is uncertain, and as a means for informing the end of tightening of the union nut, i.e., a tightening end recognizing means. There was room for improvement.

  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 is in a state close to it even in a work site under noise conditions, and to improve workability and handling. It is in providing a resin pipe joint that is improved to be superior.

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 ring member having a C-shape when viewed from the axial center P direction between the axial center P direction of the distal end 2a of the union nut 2 that is screwed into the joint body 1 and the outer peripheral flange 1A formed on the joint body 1. 18 is installed,
The ring member 18 has an outer peripheral surface 18a having a diameter equivalent to that of the outer peripheral flange 1A, a flat flat peripheral surface 18b on the union nut 2 side, and an outer diameter side on the outer peripheral flange 1A side in the axial direction. And an inclined surface K that increases in width.
As the ring member 18 is pressed and clamped between the tip 2a and the outer peripheral flange 1A by the screwing of the union nut 2, the inclined surface K of the ring member 18 and the union nut side surface 1a of the outer peripheral flange 1A The ring member 18 is configured to change in diameter.
When the seal pressing portion 10 presses the diameter change region 9 and the union nut 2 in which the seal portion S is formed is screwed, the ring member 18 is moved to the outer peripheral flange 1A and the tip 2a. There is provided a tightening end recognition means C which is set so as to change in diameter by being pressed between the two.

The invention according to claim 2 is the resin pipe joint according to claim 1, wherein a flat surface H perpendicular to the axis P is formed at an inner diameter side end of the inclined surface K, and the outer peripheral flange 1A and the end surface 2a are formed. the ring diameter change of the member 18, before SL in contact with the inclined surface K contact partner 1A and the flat surface H and the tightening limit mechanism configured ends by abutment by being pressed sandwiched between D is provided.

In the invention according to claim 3, in the resin pipe joint according to claim 1 or 2, in addition to the inclined surface 20 of the ring member 18 , an inclined surface K is formed on the union nut side surface 1a of the outer peripheral flange 1A. In addition to the flat surface H of the ring member 18, a flat surface H orthogonal to the axis P is formed on the inner diameter side of the inclined surface of the outer peripheral flange 1A.

  According to a fourth aspect of the present invention, in the resin pipe joint according to the third aspect, an arc shape or a circumference for pressing the outer diameter side portion of the ring member 18 in the axial center P direction at the tip of the union nut 2. A projection 2T having a shape is formed.

  The invention according to claim 5 is the resin pipe joint according to any one of claims 1 to 4, wherein the joint body 1 and the union nut 2 are made of a fluororesin.

  According to the first aspect of the present invention, as will be described in detail in the section of the embodiment, when the union nut is tightened by the function of the tightening end recognizing means, it is between the outer peripheral flange of the joint body and the union nut tip. The diameter of the interposed ring member changes, and the outer peripheral surface of the ring member protrudes from the outer peripheral surface of the outer peripheral flange or the union nut. Therefore, it is possible to recognize that the union nut has been tightened by visually checking the protrusion of the ring member to the outside of the diameter. As a result, even at work sites under noisy conditions, it is possible to visually confirm that the union nut has been tightened or close to it, and it is improved so that it is excellent in assembly workability and handling. A resin pipe joint can be provided.

Prevention According to the invention of claim 2, clamping limit mechanism with a simple twist of forming a flat surface on the inner diameter side end of the inclined surface of the-ring member is configured, excessive diameter changes of the ring member At the same time, the union nut can be cut off and the effect of the invention of claim 1 can be obtained while preventing damage to the components and improving the operational feeling. In this case, if the inclined surfaces are formed on both the ring member and the outer peripheral flange as in claim 3, there is also an advantage that the diameter of the ring member can be smoothly expanded and expanded as the union nut is screwed. In addition, as in the fourth aspect, if the projection that pushes the outer diameter side portion of the ring member is formed on the union nut, a smoother diameter change of the ring member can be expected.

  According to the invention of claim 5, the joint body and the union nut are formed of a fluorine-based resin excellent in chemical resistance and heat resistance, and the fluid is a chemical liquid, a chemical liquid, or a high-temperature fluid. Even if it exists, a joint structure part does not deform | transform and does not become easy to leak, but favorable sealing property and drawing-out resistance can be maintained now. A 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 showing the structure of a resin pipe joint of Example 1, FIG. 2 is a partially cutaway plan view of the resin pipe joint of FIG. 1, and FIG. 3 is an enlarged cross-sectional view of the main part showing a tightening end recognition means 4 is a cross-sectional view of the main part showing the ring member and its anti-rotation structure, FIG. 5 is a cross-sectional view taken along the line aa in FIG. 4, and FIG. 6 is a part of the resin pipe joint immediately before pressing the ring member. FIG. 7 is a partially cutaway plan view of a resin pipe joint showing a tightening limit, and FIGS. 8 to 10 are operational views of main parts showing first to third different structures of a tightening end recognition means. It is.

[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 synthetic resin represented by PFA, PTFE, etc.) and a fluororesin (synthesis represented by PFA, PTFE, etc.) are connected to tubes of different diameters or the same diameter. An example of resin) It is composed of three parts including a union nut 2 and a ring member 18. 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 and 2, the joint main body 1 includes an inner cylinder 4 (one example of a fitting cylinder) 4 that can be externally fitted by expanding the diameter of the end of the tube 3, and an inner depth of the inner cylinder 4. A cover cylinder portion 6 having a circumferential groove m extending in the direction of the axis P in order to allow entry of the tip of the tube 3 whose diameter is expanded on the outer peripheral side of the side portion, a male screw 5 made of a trapezoidal screw, and the axis P A cylindrical member having a cylindrical fluid passage 7 having a cylindrical shape. 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 hexagon nut portion 23 having a constant width in the axial center P direction, and a subsequent pipe portion (connecting portion) 25 (FIG. 2). 4 and 5).

  As shown in FIGS. 1 and 2, the joint body 1 is formed with an outer peripheral flange 1 </ b> A for constituting a tightening end recognition means C (described later) in cooperation with the end surface 2 a of the union nut 2. The outer peripheral flange 1A has an outer peripheral surface 1b having a diameter larger than that of the hexagon nut portion 23 and the male screw 5 and the same diameter as the maximum diameter of the union nut 2, and a male screw side peripheral surface (an example of a union nut side surface) 1a. Yes. The male thread side peripheral surface 1a includes an inner diameter wall surface 27 (an example of a flat surface H) that is a surface orthogonal to the axis P, and a receiving inclination that has a taper angle in a direction that falls outside the diameter toward the nut 23 side. It consists of the surface 19 (an example of the inclined surface K).

  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 side of the enlarged-diameter changing region 9 in the enlarged-diameter portion 3 </ b> A that is externally fitted to the inner cylinder 4 of the tube 3. A peripheral edge for sealing (an example of a pressing portion for sealing) 10 that can act on the end portion, a circumferential edge 11 for retaining that can act on the large-diameter side end portion of the diameter expansion change region 9, and a diameter in the expanded diameter portion 3A The presser inner peripheral portion 13 that can be externally fitted to the diameter-enlarging straight portion 12 that is surrounded by a certain straight barrel portion 4B, and the tube 3 is placed over a predetermined length in the axis P direction following the sealing peripheral edge 10. And a guide cylinder portion 14 that surrounds the guide cylinder portion 14. In addition, 2A is the outer peripheral surface to which the anti-slip process was given, 2b is a nut part.

  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 and 2, the elastic diameter can be changed between the internal thread side end surface 2a, which is the leading end of the union nut 2, and the outer peripheral flange 1A. A ring member 18 is interposed. The ring member 18 has a C shape when viewed in the direction of the axis P, and is preliminarily fitted on the mounting outer peripheral surface 1c formed between the outer peripheral flange 1A of the joint body 1 and the male screw 5. Then, the union nut 2 is screwed into the joint body 1. In order to mount on the mounting outer peripheral surface 1c, the ring member 18 may be fitted from the inner cylinder 4 side with a slightly expanded diameter, moved in the direction of the axis P and moved over the male screw 5.

  As shown in FIGS. 1 to 4, the ring member 18 has an outer peripheral surface 18 a having a diameter equivalent to that of the union nut 2 and the outer peripheral flange 1 </ b> A in a free state, and is flat on the union nut side (perpendicular to the axis P). A flat side peripheral surface 18b, a composite side peripheral surface (an example of an outer peripheral flange side surface) 18c inclined most on the outer peripheral flange side, a pair of opposing dimensional sections 18d, etc., and a flexible material. (Synthetic resin such as fluororesin, metal, rubber, etc.). The composite side peripheral surface 18c is formed of a small-diameter flat surface 24 (an example of the flat surface H) at the inner diameter end and a push inclined surface 20 (an example of the inclined surface K) that occupies most of the outer diameter. The push inclined surface 20 has a taper angle in a direction in which the width in the direction of the axis P increases toward the outer side of the diameter.

  As shown in FIGS. 4 to 6, the joint body 1 has a stopper portion 26 for preventing the ring member 18 from rotating with respect to the joint body 1 around the axis P. Are integrally formed. The stopper portion 26 has an inner diameter side ring surface 26a that rises from the outer peripheral surface 1c for mounting, and an outer diameter side that projects less toward the union nut in the axial center P direction than the inner diameter side ring surface 26a. The protrusions are narrow in the circumferential direction having a ring surface 26b and an outer peripheral surface 26c having an outer diameter smaller than the outer peripheral flange 1A and larger than the innermost inner diameter of the receiving inclined surface 19.

  The diameter of the step side peripheral surface 26d at the boundary between the inner diameter side ring surface 26a and the outer diameter side ring surface 26b is such that the end surface 2a of the union nut 2 can push the ring member 18 to the tightening limit (described later). It is set to a value slightly smaller than the minimum diameter of 2a. Further, the maximum diameter of the stopper portion 26 is such that a diameter capable of exhibiting the detent function is ensured even when the ring member 18 is expanded to the tightening limit (described later). In the first embodiment, the ring member 18 mounted on the mounting outer peripheral surface 1c is configured to prevent the ring member 18 from coming off to the opposite side of the outer peripheral flange in the direction of the axis P by the presence of the male screw 5. In the case where the outer peripheral surface 1c is larger than the maximum diameter (mountain diameter) of the male screw 5, there can be means for providing the mounting outer peripheral surface 1c integrally or separately with a small protrusion.

  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. The diameter-enlarged portion 3A that is externally fitted to the inner cylinder 4 is fitted to the diameter-enlarged change region 9 that is externally fitted to the outer peripheral surface 4a of the cylindrical portion 4A having a tapered tip and the outer peripheral surface 4b of the straight barrel portion 4B. The enlarged diameter straight portion 12 is formed.

  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 held 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. Note that the pressing by the retaining peripheral edge 11 and the pressing by the sealing peripheral edge 10 may be performed simultaneously.

  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.

  Next, the tightening end recognition means C will be described. This resin pipe joint A is a tightening that can visually recognize the end of tightening of the union nut 2 (or that the end is near) in the state of assembly in which the tube 3 is inserted and fixed with the union nut 2. An end recognition means C is provided.

  That is, a ring member 18 having a C-shape as viewed in the axial center P direction is interposed between the axial center P direction of the end face 2a as the tip of the union nut 2 on the joint body 1 and the outer peripheral flange 1A. As the ring member 18 is pressed and clamped between the end face 2a and the outer peripheral flange 1A by the union nut 2 being screwed, the outer peripheral flange 1A and the ring member 18 ("any one of these three members 2a, 1A, 18" The ring member 18 is configured to change in diameter by the inclined surfaces 19 and 20 formed on the end face in the axial center P direction of “one or more examples”. The end surface 2a is a tip surface of a convex ring (an example of “arc-shaped or circumferential projection”) 2T formed at the tip of the union nut to press the outer diameter side portion of the ring member 18 in the direction of the axis P. It is.

  Thus, the ring member 18 sandwiched between the end surface 2a and the outer peripheral flange 1A by screwing the union nut 2 in the tightening direction has the pushing inclined surface 20 and the receiving inclined surface 19 in the direction of the axis P. Due to the component force that is pressed against the outer surface, the outer surface is forcibly expanded outwardly and begins to protrude outwardly. That is, as shown in FIGS. 2 and 3, when the ring member 18 protrudes to the outside of the diameter from the outer peripheral flange or the union nut 2 to some extent, the sealing peripheral edge 10 presses the expanded diameter change region 9 and seals it. The union nut 2 in which the part S is formed is set so as to be in the screwing end state.

  That is, the outer peripheral flange 1A and its receiving inclined surface 19, the ring member 18 and its pushing inclined surface 20, and the end surface 2a of the union nut 2 constitute the tightening end recognition means C, and the sealing peripheral edge 10 is formed. When the union nut 2 in which the seal portion S is formed by pressing the diameter expansion change region 9 is brought into a screwing end state (an assembly end state of the resin pipe joint A), the ring member 18 is moved between the outer peripheral flange 1A and the end face 2a. It is set so as to change in diameter by being pinched between. Therefore, the operator who operates the union nut 2 can recognize that the ring member 18 has reached the tightening end state (or almost the tightening end state) by visual observation of the state in which the diameter of the ring member 18 has changed. At that time, the turning operation is finished.

  The actual tightening operation procedure will be described. When the union nut 2 is turned and screwed, the end surface 2a is brought into contact with the ring member 18 immediately after the end surface 2a touches the ring member 18 as shown in FIG. The ring member 18 starts to be compressed in the direction of the axis P between the outer peripheral flange 1A and pressed against the flat peripheral surface 18b. Subsequently, when the union nut 2 is rotated in the tightening direction to reach the end of tightening, as shown in FIGS. The surface 18a is configured to protrude more clearly than the outer peripheral surface 1b of the outer peripheral flange 1A. Accordingly, it is possible to recognize that the tightening has been completed by visually confirming that the ring member 18 has protruded to the outside of the diameter.

  In this way, it is possible to know the end of tightening by visually observing the change in the diameter of the ring member 18, so that it is confirmed that the union nut is at or near the end of tightening even at a work site under noise conditions. Has been improved so that the assembling workability and handleability of the resin pipe joint are excellent. As shown in FIGS. 2 and 3, the push inclined surface 20 still protrudes radially inward from the receiving inclined surface 19 in the tightened state, so that the union nut 2 can be further turned in the tightening direction. In other words, retightening is possible.

As shown in FIG. 7, the tightening limit (tightening limit) of the union nut 2 is such that when the union nut 2 is further turned to change the diameter of the ring member 18, the small-diameter flat surface 24 of the ring member 18 When it comes into contact with the inner diameter wall surface 27 of the flange 1A, no further change in the diameter is made impossible, and the screwing of the union nut 2 is finished. That is, press the inclined surface diameter changes of the ring member 18 by being pressed held between the outer peripheral flange 1A and the end face 2a is tripartite, i.e. the end face 2a, the outer peripheral flange 1A, a ring member 18 caries Chino inclined surface K There is provided a tightening limit mechanism D configured to end when the outer peripheral flange 1 </ b> A as a contact partner in contact with 20 and the small-diameter flat surface 24 as the flat surface H come into contact with each other.

[ Reference example]
As a first reference structure of the tightening end recognition means C, as shown in FIG. 8, the end surface 2a and the outer peripheral flange 1A have no inclined surface K, and only the ring member 18 has a push inclined surface 20 (inclined surface K). It is possible to adopt the configuration described above. In this case, in a free state where the ring member 18 is not pressed in the axis P direction, the diameter of the outer peripheral surface 1b of the outer peripheral flange 1A is slightly smaller than the diameter of the outer peripheral surface 18a of the ring member 18 (= the diameter of the union nut 2). Keep it. A small-diameter flat surface (flat surface H) for forming the tightening limit mechanism D is formed inside the push inclined surface 20. 8 shows the state immediately before the ring member 18 is pressed on the left side of the drawing, and the tightening end state is shown on the right side of the drawing.

As a second reference structure of the tightening end recognition means C, as shown in FIG. 9, a receiving inclined surface 19 (inclined surface K) having a minimum diameter smaller than the inner diameter of the ring member 18 is formed only on the outer peripheral flange 1A. The end surface 2a and the ring member 18 can have a configuration having no inclined surface. The flat surface H for constituting the tightening limit mechanism D is formed following the radially outer side of the receiving inclined surface 19 in the outer peripheral flange 1A. 9 shows the state immediately before the ring member 18 is pressed on the left side of the drawing, and the tightening end state is shown on the right side of the drawing.

As a third reference structure of the tightening end recognition means C, as shown in FIG. 10, the nut portion 2b (FIG. 1, FIG. 1) is inclined toward the inclined surface having the smallest diameter smaller than the inner diameter of the ring member 18, that is, the outer diameter. It is also possible to adopt a configuration in which the inclined surface K inclined so as to fall in the direction approaching 2) is formed only on the union nut 2, and the ring member 18 and the outer peripheral flange 1A have no inclined surface K. The flat surface H for constituting the tightening limit mechanism D is formed following the radially outer side of the inclined surface K in the union nut 2, and the inclined surface K and the flat surface H form an end surface 2 a. Note that the state immediately before the ring member 18 is pressed is shown on the left side of FIG. 10 and the tightening end state is shown on the right side of the page.

Sectional drawing which shows the structure (tightening completion state) of the resin pipe joint by Example 1 FIG. 1 is a partially cutaway plan view showing the resin pipe joint of FIG. Enlarged sectional view of the main part showing the tightening end recognition means Sectional drawing of the principal part which shows a ring member and its rotation prevention structure Sectional drawing of the aa line in FIG. Partially cutaway plan view of a resin pipe joint showing immediately before pressing the ring member Partial cutaway plan view of resin pipe fitting showing the tightening limit (tightening limit) Action diagram of main part showing outline of first reference structure of tightening end recognition means Action diagram of main part showing outline of second reference structure of tightening end recognition means Action diagram of main part showing outline of third reference structure of tightening end recognition means

DESCRIPTION OF SYMBOLS 1 Joint body 1A Outer flange 1a Union nut side surface 2 Union nut 2T Protrusion 2a Tip 3 Tube 3A Expanded diameter part 4 Fitting cylinder 5 Male thread 8 Female thread 9 Diameter expansion change area 10 Seal pressing part 18 Ring member 18c Peripheral flange side surface C End recognition means D Tightening limit mechanism H Flat surface K Inclined surface 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 ring member having a C-shape as viewed in the axial direction is interposed between the axial direction between the tip of the union nut that is screwed into the joint body and the outer peripheral flange formed on the joint body,
The ring member is
An outer peripheral surface having the same diameter as the outer peripheral flange;
A flat flat peripheral surface on the union nut side;
The outer peripheral flange side has an inclined surface whose width in the axial direction increases toward the outer diameter side,
As the ring member is pressed and clamped between the tip and the outer peripheral flange by screwing of the union nut, the diameter of the ring member is changed by the inclined surface of the ring member and the union nut side surface of the outer peripheral flange. Configured to
When the seal pressing portion presses the diameter change region and the union nut where the seal portion is formed is screwed, the ring member is pressed and clamped between the outer peripheral flange and the tip. A resin pipe joint provided with a tightening end recognizing means set so as to change in diameter. Contact the perpendicular to the axis on the inner diameter side end of the inclined surface to form a flat surface, diameter changes of the ring member by being pressed held between said tip and said outer peripheral flange, which is in contact with the front Symbol inclined surface The resin pipe joint according to claim 1, wherein a tightening limit mechanism configured to end when the counterpart and the flat surface come into contact with each other is provided. The inclined surface on the union nut side surface of the outer peripheral flange in addition to the inclined surface of the ring member is formed, and, on the axis on the inner diameter side of the inclined surface in the outer peripheral flange in addition to the flat surface of the ring member The resin pipe joint according to claim 1 or 2, wherein an orthogonal flat surface is formed.   The resin pipe joint according to claim 3, wherein an arc-shaped or circumferential projection for pressing an outer diameter side portion of the ring member in an axial direction is formed at a tip of the union nut.   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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