JP2010223291A - Resin pipe joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin pipe joint improved to be excellent in assembly work efficiency and handling properties to confirm that tightening of a union nut is ended or almost ended even in a noisy work site. <P>SOLUTION: In the resin pipe joint, the union nut 2 advances by screwing a male screw 5 into a female screw 8 in a state that a tube 3 is externally fitted to an inner cylinder 4 to form a diameter-enlarged part 3A, and a diameter-enlarged change region 9 is pressed by a pressing part 10 for sealing. A tightening completion recognition means C is provided so that a cylindrical projection 18 formed on a joint body 1 projects into a recession 19 formed on an end of the union nut 2 when the union nut 2 is in the advancing end state that the pressing part 10 for sealing presses the diameter-enlarged change region 9 and a seal part S is formed. <P>COPYRIGHT: (C)2011,JPO&INPIT

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 internally fitted in a fitting cylinder of the 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 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 Will be done. Therefore, it is often impossible for the operator to hear the sound of the resin protruding piece, and there is still room for further improvement as means for notifying the end of tightening of the union nut, that is, a means for recognizing the end of tightening. It was a thing.

  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 direction of the axis P of the joint body 1 by screwing the female screw 8 with the male screw 5 in a state where the tube 3 is fitted and attached to the fitting cylinder 4, In the resin pipe joint configured such that the diameter-enlarged change region 9 is pressed in the axial center P direction by the seal pressing portion 10 to form the seal portion S.
A rod-like portion 18 projecting in the radial direction with respect to the shaft center P, and a recessed portion 19 that allows the rod-like portion 18 to enter as the screw advances, and the end portion in the shaft center P direction of the union nut 2 When the union nut 2 is formed in the joint body 1 and the seal pressing portion 10 presses the diameter change region 9 to form the seal portion S, the union nut 2 is in a screwing end state or just before it. The fastening end recognizing means C is set so that the rod-like portion 18 enters the recessed portion 19.

  According to a second aspect of the present invention, in the resin pipe joint according to the first aspect, the rod-shaped portion 18 is formed in a cylindrical body having a circular shape when viewed in the radial direction, and the width dimension of the recessed portion 19 is that of the rod-shaped portion 18. It is characterized by being set to substantially the same value as the diameter.

  According to a third aspect of the present invention, in the resin pipe joint according to the first or second aspect, the state in which the rod-shaped portion 18 is press-fitted into the recessed portion 19 and the state in which the rod-shaped portion 18 is loosely fitted are accompanied by the screwing. Concavities and convexities or undulations 24 and 26 are formed in contact portions of the recessed portions 19 with the rod-shaped portions 18 so as to appear alternately.

  According to a fourth aspect of the present invention, in the resin pipe joint according to any one of the first to third aspects, the rod-shaped portion 18 and the inlet of the recessed portion 19 are located at the end when the union nut 2 is in a screwing-end state. The recessed length of the recessed portion 19 is set so as to be located in the middle of the back.

  According to a fifth aspect of the present invention, in the resin pipe joint according to any one of the first to fourth aspects, the recess 19 is opened at an end in the axis P direction and is inclined with respect to the axis P. It is formed in the union nut 2 as a notch, and the rod-shaped portion 18 is projected from the outer peripheral portion of the joint body 1 toward the radially outer side.

  The invention according to claim 6 is the resin pipe joint according to any one of claims 1 to 5, wherein the joint body 1 and the union nut 2 are made of a fluororesin.

  According to the invention of claim 1, although described in detail in the section of the embodiment, when the tightening of the union nut is advanced by the function of the tightening end recognizing means, either the joint body or the union nut is shaped like a rod. The situation where the part enters one of the other recessed parts appears. Therefore, by visually confirming that the rod-like portion enters the recessed portion, it can be recognized that the union nut has been tightened. As a result, the resin pipe joint is improved so that it can be confirmed that the union nut has been tightened or is close to it even in a work site under noisy conditions, and the assembly workability and handling are excellent. Can be provided.

  According to the invention of claim 2, since the rod-shaped portion is cylindrical, it is convenient that the width dimension of the recessed portion can be set to a constant width regardless of the angle of entry, and the width dimension and the rod-shaped portion. Therefore, there is an advantage that it is easy to distinguish whether or not the rod-like portion has entered the recessed portion, and therefore it is easy to confirm the completion of tightening visually.

  According to the invention of claim 3, since the concave portion is provided with irregularities or undulations, the state in which the rod-like portion is press-fitted into the concave portion and the state in which the rod-like portion is loosely fitted alternately appear as the union nut is screwed. Resin pipe fittings that allow the operator to sense the moderation of turning the union nut and recognize that the tightening end state has been reached even with an operational feeling in addition to visual observation. Can be provided.

  According to the invention of claim 4, since the rod-like portion can be moved further into the recessed portion from the tightening end state, additional tightening can be performed to eliminate slack due to secular change or creep, and there is a practical advantage. It ’s big.

  According to the invention of claim 5, since the rod-shaped portion is formed on the joint body and the recessed portion is formed on the union nut, the union nut is screwed onto the joint body as compared with the opposite configuration. Therefore, there is an advantage that the effect according to the first to fourth aspects of the invention can be obtained easily.

  According to the invention of claim 6, 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 the resin pipe joint of Example 1, FIG. 2 (a) is a schematic plan view of the resin pipe joint of FIG. 1, (b) is a developed view near the protrusion, and FIG. ) Is a schematic plan view of the resin pipe joint in a state immediately before the protrusion enters the recessed portion, (b) is a developed view of the vicinity of the protrusion, and FIG. 4 is a schematic view of the resin pipe joint in a state immediately after the protrusion enters the recessed portion. FIG. 5B is a developed view of the vicinity of the protrusion, FIG. 5 is a developed view of the main part showing the case where the protrusion is pressed into the recessed portion, and FIG. 6A is an outline of the resin pipe joint in the tightened state. FIG. 7B is a developed view of the vicinity of the protrusion, and FIG. 7 is a schematic plan view of the resin pipe joint of the second embodiment. The recessed portions 19 in FIGS. 2 to 4, 6, and 7 (a) are not drawn exactly based on trigonometry, but are deformed (transformed).

[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 two parts including a union nut 2 made of 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 and 2, the joint main body 1 includes a fitting cylinder 4 at one end that can be externally fitted by expanding the end of the tube 3, and an outer peripheral side of the inner back side portion of the fitting cylinder 4. A cylindrical cylindrical space having a cover cylinder portion 6 having a circumferential groove m extending in the direction of the axis P to allow the tip of the tube 3 having a diameter expanded to a diameter, a male screw 5 formed of a trapezoidal screw, and the axis P Are formed in a cylindrical member including the fluid path 7 and the outer peripheral flange 1A. The fitting cylinder 4 is a tapered straight having a tip tapered cylinder 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 tip tapered cylinder portion 4A. It is structured as a shape.

  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 distal end surface of the fitting cylinder 4 is provided with a reverse taper angle that is closer to the inner inner side (the inner side in the axial center P direction) toward the inner side in the radial direction, that is, a cut surface 16 having a larger diameter toward the distal end is formed. 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, 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 (see FIG. 2). ) Is formed.

  As shown in FIGS. 1 and 2 and the like, the joint body 1 has a mechanism outer peripheral surface 1c having a diameter equal to (or larger than) the diameter of the male screw 5 following the male screw side surface 1a of the outer peripheral flange 1A. Formed there is integrally formed a projection (an example of a rod-like portion) 18 in the form of a cylindrical body (a cylindrical body that exhibits a circular shape in the radial direction) standing up toward the outside of the diameter. The protrusion 18 is a component for constructing a tightening end recognizing means C (described later) by being fitted into a recess 19 (described later) of the union nut 2 as the union nut 2 is screwed. The protrusion 18 has a shape having a constricted base end portion 20 that is thinned so as to be easily elastically deformed, as shown in a blow-out view in FIG. 1, or a cylinder that is closer to the axis P in the radial direction, although not shown. A shape having a fan shape as viewed in the axial direction may be used so that the diameter of the lens becomes smaller. The outer peripheral surface 1b of the outer peripheral flange 1A has the same diameter as the outer diameter of the union nut 2.

  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, a sealing peripheral edge (an example of a pressing portion for sealing) 10, a retaining peripheral edge 11, and a presser An inner peripheral portion 13 and a guide tube portion 14 are provided. The peripheral edge 10 for sealing is a portion that can be pressed in the direction of the axis P by abutting against the end portion on the small diameter side of the diameter expansion change region 9 in the diameter expansion portion 3A that is externally fitted to the fitting cylinder 4 of the tube 3. . The retaining peripheral edge 11 is a portion that can be pressed in the direction of the axis P by contacting the large-diameter side end portion of the diameter expansion change region 9. The presser inner peripheral portion 13 is a place that can be externally fitted to the enlarged diameter straight portion 12 surrounded by the straight barrel portion 4B having a constant diameter in the enlarged diameter portion 3A. The guide cylinder portion 14 is a location that surrounds the tube 3 over a predetermined length in the direction of the axis P following the sealing peripheral edge 10. In addition, 2A is a union nut main body by which the outer peripheral surface was given the non-slip process, 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 outer peripheral edge 11 for retaining is larger in diameter than the outer peripheral surface 4b of the straight barrel portion 4B, which is the maximum diameter of the fitting cylinder 4, and the thickness of the tube 3 is added. Although it is set to a value smaller than the diameter, that is, the diameter of the presser inner peripheral portion 13, it may not be (for example, smaller than the outer peripheral surface 4 b), and may act on the larger diameter side portion of the diameter expansion change region 9. It ’s fine. 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.

  At the end of the union nut 2 on the outer peripheral flange 1A side in the axial center P direction, as shown in FIG. 2 to FIG. A recessed portion 19 is provided. The recessed portion 19 is a portion that allows the rod-shaped portion 18 to enter as the union nut 2 is screwed, and the width of the recessed portion 19 is the same as the diameter of the rod-shaped portion 18 formed in a cylindrical body that is circular in a radial direction. It is set to almost the same value. Of the side walls 19A and 19B forming the recessed portion 19, the inner side wall 19A which is the inner back side in the direction of the axis P is a protruding wall portion 24 in which the distance from the outer side wall 19B is slightly smaller than the diameter of the protrusion 18. And the recessed wall part 26 for loosely fitting the protrusion 19 is formed in a state that appears alternately in the longitudinal direction of the recessed part 19. Note that X is the center line of the recessed portion 19, and it is desirable that the angle θ with the axial center P coincide with the pitch angle of the female screw 8.

  Next, in order to externally insert the end of the tube 3 into the fitting cylinder 4, the tube 3 is forcibly pushed in at room temperature to increase the diameter, or it is warmed using a heat source and easily deformed by expansion. Then, the tube end 3t is moved as shown in FIG. 1 by pushing it in, or by expanding the tube end in advance using a diameter expander (not shown) and then pushing it into the fitting cylinder 4. It is inserted until it is in a state located inside the end wall 15 of the cover tube portion 6. The diameter-enlarged portion 3A that is externally fitted to the fitting cylinder 4 is externally attached to the diameter-changing 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. It consists of an enlarged diameter straight part 12 to be fitted.

  That is, as shown in FIG. 1, the axis 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 fitting cylinder 4. The presser inner peripheral portion 13 is externally fitted to the diameter-enlarged straight portion 12 and the portion having a larger diameter than the diameter of the fitting cylinder 4 in the larger-diameter side portion of the diameter-enlargement changing region 9 is removed. It is set so that it is pressed in the axis P direction by the peripheral edge 11 for stopping, and the small diameter side portion of the diameter expansion change region 9 is pressed in the direction of the axis P by the peripheral edge 10 for sealing. 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 fitting cylinder 4 are slightly separated from each other in the direction of the axis P. However, when the angle of the outer peripheral surface 4a is abrupt, the separation distance is increased, and when the angle is loose, the separation distance is increased. The 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 fitting tube 4 without any fluid such as cleaning liquid or chemical solution entering between the fitting tube 4 and the enlarged diameter portion 3A. Yes.

  The diameter-enlarging straight part 12 of the diameter-enlarging part 3A that is press-fitted to the fitting cylinder 4 is surrounded by the outer peripheral surface 4b of the straight barrel part 4B and the presser inner peripheral part 13, and first expands. It is held so that it cannot be deformed, and the circumferential edge 11 for retaining is positioned so as to substantially bite into the enlarged 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 expanded diameter portion 3A in the direction of coming out of the fitting 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. An action of trying to push the enlarged diameter straight portion 12 into the inner side of the fitting cylinder 4 by the tightening operation occurs. The above describes the state in which the pressing of the small diameter side portion of the enlarged diameter change region 9 by the sealing peripheral edge 10 is started after the pressing of the large diameter side portion 9 of the enlarged diameter changing region 9 by the retaining edge 11 is started. However, the present invention is not limited to such a state, and the same action occurs when the retaining peripheral edge 11 and the sealing peripheral edge 10 simultaneously contact the tube 3.

  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. 4 to insert the tube into the joint body 1 more reliably, or in addition to this, the enlarged diameter straight portion 12 pushed in the axis P direction moves in the axis P direction. Therefore, it is possible to obtain a preferable effect that the pressure contact force is further increased and the pinch is firmly clamped in an attempt to expand in the radial direction due to difficulty. When the pressure contact force is relatively strong, the diameter-enlarging straight portion 12 pushed in the direction of the shaft center P does not move in the direction of the shaft center P first, thereby causing a strong action to expand in the radial direction. The diameter-enlarging straight portion 12 is more firmly held between the presser inner peripheral portion 13 and the presser inner peripheral portion 13.

  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 press-contact holding force of the tube 3 with respect to the fitting cylinder 4 and the pull-out resistance.

  Further, as shown in FIG. 1, the tube 3 is formed by a circumferential groove m formed by the inner back side of the fitting tube 4 and the cover tube portion 6 and a union nut 2 formed by fluoroscopic fluororesin. The indicator means B that can visually check whether or not it is correctly inserted into the fitting 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 fitting 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.

  Due to the presence of the circumferential groove m and the cover cylinder portion 6 for constituting the indicator means B, an effect of functioning as an indicator when the tube 3 is inserted into the fitting cylinder 4 is also obtained. That is, it can be confirmed whether or not the amount of insertion into the fitting 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 fitting cylinder 4 is located behind the end wall 15, and the quality can be visually determined when the tube 3 is assembled to the fitting cylinder 4. As an advantage.

  The indicator means B clearly recognizes the position of the diameter-enlarged portion 3A by visual observation on the inner side of the presser inner peripheral portion 13 and through a line passing through the valley-shaped inner peripheral surface 22 until reaching the female screw 8. It is easy.

  As the union nut 2 is screwed, the diameter-enlarged portion 3A of the tube 3 is covered with the union nut 2 and becomes invisible, but the retaining peripheral edge 11 and the sealing peripheral edge 10 described in the paragraph number “0036” Due to the pushing action of the enlarged diameter straight portion 12 due to the above, the enlarged diameter straight portion 12 is reliably moved toward the circumferential groove m.

  Therefore, the diameter-enlarged portion 3A can be seen from the valley-shaped inner peripheral surface 22, and the tube 3 after the union nut 2 is tightened by the visual confirmation function of the indicator means B that can visually recognize the normal state of the tube insertion state. An assembled state can be guaranteed, and a resin pipe joint A having high rigidity and excellent sealing performance can be provided.

  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, as the union nut 2 is turned and tightened, the tightening is finished when the protrusion 18 enters the recessed portion 19, and the protrusion 18 moves into the recessed portion 19. If it can be confirmed by visual observation, the completion of assembly can be perceived.

  That is, as shown in FIGS. 2 to 6, the tightening end recognition means C is in a state where the unsealing of the union nut 2 in which the seal peripheral edge 10 presses the diameter-enlargement change region 9 and the seal portion S is formed. (Or the state immediately before that), the projection 18 is set so as to enter the recessed portion 19. The average width dimension of the recessed portion 19 is substantially matched to the diameter of the protrusion 18, but may be somewhat wider. However, it is desirable that the protrusion 18 is in contact with or pressed against the inner side wall 19A even if it is somewhat wide. As shown in FIG. 1, the protrusions 18 are formed at two positions 180 degrees apart with respect to the axis P, and there are two corresponding recessed portions 19. However, only one or three or more are provided. A certain tightening end recognition means C may be used.

  As described above, the recessed portion 19 has an inner side wall in which the protruding wall portion 24 and the recessed wall portion 26 are alternately repeated. Therefore, the protrusion behavior of the protrusion 18 into the recessed portion 19 due to the screwing of the union nut 2 includes the press-fit state in which the protrusion 18 is pressed and clamped by the urging wall portion 24 and the outer side wall 19B, and the recessed wall portion 26 and the outer The protrusions 18 are configured to appear alternately with the loosely fitted state in which the protrusions 18 are loosely or pinched with the side wall 19B. That is, unevenness or undulations 24 and 26 are formed on the inner side wall 19A which is a contact portion with the rod-shaped portion 18 of the recessed portion 19.

  The operation of the tightening end recognition means C will be described. In a situation immediately before the pressing peripheral edge 10 starts to press the diameter expansion change region 9 by tightening and screwing the union nut 2, FIG. , (B), the protrusion 18 has not yet reached the recessed portion 19 and is in a positional relationship slightly separated. In a situation where the union nut 2 is tightened and the pressing peripheral edge 10 starts to press the diameter change region 9, the protrusion 18 starts to enter the recess 19 as shown in FIGS. 4 (a) and 4 (b). A state is brought about. At this time, the protrusion 18 is positioned on the first recessed wall part 26 beyond the first protruding wall part 24 at the entrance of the recessed part 19, and the outer side wall 19 </ b> B does not act on the protrusion 18 and the recessed part 19. It is in a loose fitting state (see FIG. 4B).

  In addition, in a situation where the union nut is tightened and the pressing peripheral edge 10 presses against the diameter-enlargement change region 9 and the seal portion S is formed, as shown in FIGS. The projection 18 is sandwiched between the inner side wall 19 </ b> A and the outer side wall 19 </ b> B, which is located in the middle of the longitudinal direction of 19. Therefore, the operator can recognize that the resin pipe joint A is in the tightening end state by observing that the protrusion 18 is sandwiched between the both side walls 19A and 19B of the inner outer and enters the recessed portion 19. Thereby, the turning operation of the union nut 2 is completed. This is a function for notifying the operator that the tightening is completed by the tightening end recognition means C.

  As shown in FIG. 5, when passing between the protruding wall portion 24 and the outer side wall 19B in a press-fitted state, both the protrusion 18 and the protruding wall portion 24 are elastically deformed (imaginary line in FIG. 5). The cantilevered outer side wall 19B may be slightly elastically deformed. In this case, if the shape of the protrusion 18 is a shape having the constricted base end portion 20 drawn in a balloon diagram in FIG. 1, it can be easily elastically deformed and function well.

  That is, the protrusion 18 is set to enter the recessed portion 19 when the union nut 2 in which the seal portion S is formed is in a screwing end state or just before that. In short, the union nut 2 is screwed onto the joint body 1 and turned in the tightening direction, and tightened when it can be visually observed that the protrusion 18 has entered the recessed portion 19 while being sandwiched between both side walls 19A and 19B of the inner outer. What is necessary is just to perform operation of ending attachment. In addition, the protruding wall portions 24 and the recessed wall portions 26 are alternately provided on the inner side wall 19A where the protrusion 18 is rubbed, so that the state where the protrusion 18 is press-fitted and the state where the protrusion 18 is loosely fitted appear alternately. Thus, the detent mechanism is substantially configured. Therefore, after the union nut 2 is turned and the projection 18 reaches the inner side wall 19A, it is possible to recognize that the tightening end state has been reached by the sense that the union nut 2 is turned moderately. ing. Thereby, there exists an advantage which can anticipate the synergistic effect with the cognitive effect | action of the completion | finish of fastening by visual observation mentioned above.

  In addition, as described above, the recessed length of the recessed portion 19 is set so that the protrusion 18 is positioned between the entrance and the innermost position of the recessed portion 19 in the unscrewed state of the union nut 2. As a result, retightening is possible. That is, as shown in FIGS. 6 (a) and 6 (b), since the recessed portion 19 still continues to the back in the tightened end state, the union nut 2 is further rotated until the protrusion 18 is located in the inside. Tightening, that is, additional tightening can be performed.

[Example 2]
The tightening end recognition means C may have a recess 19 in which the inner side wall 19 </ b> A and the outer side wall 19 </ b> B in FIGS. As shown in FIG. 7, the recessed portion 19 formed at the end of the union nut 2 includes an outer side wall 19B in which a protruding wall portion 24 and a recessed wall portion 26 are formed, and a straight inner side wall 19A. It has a structure. That is, the unevenness or undulations 24, 26 formed on the outer side wall 19B in the resin pipe joint of Example 1 are formed on the inner side wall 19A, and the outer side wall 19B is a flat (straight) wall surface. The recessed portion 19 shown in FIGS. 2 to 6 is configured such that the position in the axial center P direction is upside down.

  The operation and effect of the tightening end recognizing means C according to the second embodiment are the same as the operation and effect of the tightening end recognizing means C of the first embodiment, and the description thereof is omitted. However, in the configuration of the second embodiment, when a tensile stress is applied to the union nut 2 in a direction away from the outer peripheral flange 1A in the direction of the axis P, the projection 18 has the recessed wall portion 26 (outer side wall 19B). Therefore, the union nut 2 is prevented from loosening. Therefore, it is possible to maintain a stable sealing performance for a long period in the resin pipe in which the tensile stress is easily applied to the union nut 2. In the configuration of the second embodiment, it is more preferable that the recessed wall portion 26 is configured to have a small curvature recess such as a circumference so that the movement of the protrusion 18 from the recessed wall portion 26 can be inhibited.

[Another Example]
The tightening end recognition means C may be configured such that the recessed portion 19 is disposed on the joint body, and the rod-shaped portion 18 such as a protrusion is disposed on the union nut 2.

Sectional drawing which shows the structure (tightening completion state) of the resin pipe joint by Example 1 The resin pipe joint of FIG. 1 is shown, (a) is a schematic plan view, and (b) is a development view near the protrusion. The resin pipe joint in a state immediately before the protrusion enters the recessed portion is shown. The resin pipe joint in a state immediately after the protrusion enters the recessed portion is shown, (a) is a schematic plan view, and (b) is a development view near the protrusion. Exploded view of the main part showing the case where the protrusion is pressed into the recessed part The resin pipe joint in the tightened state is shown, (a) is a schematic plan view, (b) a development view near the protrusion. The resin pipe joint by Example 2 is shown, (a) is a schematic top view, (b) The developed view of protrusion vicinity

DESCRIPTION OF SYMBOLS 1 Joint body 2 Union nut 3 Tube 3A Expanded part 4 Fitting cylinder 5 Male thread 8 Female thread 9 Expanded diameter change area 10 Sealing pressing part 18 Bar-shaped part 19 Recessed part 24, 26 Concavity and convexity P Shaft center tightening C Tightening Termination recognition means S Seal part

Claims (6)

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 rod-shaped portion projecting in the radial direction with respect to the shaft center and a recessed portion that allows the rod-shaped portion to enter as the screw advances are distributed to the axial direction end portion of the union nut and the joint body. The rod-shaped portion enters the recessed portion when the seal pressing portion presses the diameter change region and the union nut in which the seal portion is formed is in a screwing end state or just before that state. A resin pipe joint provided with a tightening end recognizing means set so as to be.   2. The resin pipe joint according to claim 1, wherein the rod-shaped portion is formed in a cylindrical body having a circular shape in a radial direction, and a width dimension of the recessed portion is set to be substantially equal to a diameter of the rod-shaped portion.   Asperities or undulations are formed in the contact portion of the recessed portion with the rod-shaped portion so that the state in which the rod-shaped portion is press-fitted into the recessed portion and the loosely fitted state appear alternately with the screwing. The resin pipe joint according to claim 1 or 2.   The recessed length of the recessed portion is set such that the rod-shaped portion is positioned between the entrance and the innermost portion of the recessed portion in the unscrewed state of the union nut. The resin pipe joint according to any one of the above.   The concave portion is formed in the union nut as a notch that opens toward the axial center end and is inclined with respect to the axial center, and the rod-shaped portion protrudes from the outer peripheral portion of the joint body toward the radially outer side. The resin pipe joint as described in any one of Claims 1-4.   The resin pipe joint according to any one of claims 1 to 5, wherein the joint body and the union nut are made of a fluororesin.

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