JP4885201B2 - Resin pipe fitting - Google Patents

Description

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

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

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

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

  For example, if the pipe joint is exposed and deployed in a state where the operator can see completely, the tightening end state is confirmed by the position confirmation of the screwing condition accompanying the tightening of the union nut, or close to it. It is relatively easy to know that it will be in a state. However, pipe joints are often placed in narrow spaces between other devices, hidden places behind the ceiling, etc., and are often not visible or difficult. It is often a tightening operation. Therefore, it has been necessary to notify the operator by some means that the union nut has been tightened or has come to an end even if it cannot be visually recognized.

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 that the union nut is at or near the end of tightening even at a work site where the pipe joint portion is invisible or difficult to see and under noise conditions. This is to provide a resin pipe joint that can be confirmed and improved so as to be excellent in assembly workability and handling.

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 diameter-enlarged change region 9 is pressed in the axial center P direction by the sealing pressing portion 10 to form the sealing portion S.
A convex part 20 projecting in the direction of the axis P and a concave part 19 recessed in the direction of the axis P so as to fit into the outer periphery part of the joint body 1 and the outer peripheral part of the end part in the axial direction of the union nut 2 The convex portion 20 and the concave portion 19 are arranged in accordance with the tightening rotation from near the end of screwing of the union nut 2 when the seal pressing portion 10 presses the diameter expansion change region 9. And a torque fluctuation portion 26 that is fitted and detached from each other by a deflection displacement in the direction of one of the axes P.

  The invention according to claim 2 is the resin pipe joint according to claim 1, wherein the convex portion 20 is on the outer peripheral flange 1 </ b> A of the joint body 1, and the concave portion 19 is on the female thread forming side of the union nut 2. The protrusions 20 and the outer peripheral flange 1 </ b> A are formed at end portions, respectively, and are configured to be able to bend and displace in the direction of the axis P.

  According to a third aspect of the present invention, in the resin pipe joint according to the second aspect, the convex portion 20 is formed with a protruding portion 20B that protrudes radially outward from the outer peripheral surface 1b of the outer peripheral flange 1A. A protruding portion 24 that protrudes radially outward is formed in a portion adjacent to the concave portion 19 in the axial center P direction.

  The invention according to a fourth aspect is the resin pipe joint according to any one of the first to third aspects, wherein a plurality of the convex portions 20 and / or the concave portions 19 are formed in the circumferential direction, and the union nut 2 It is configured such that the fitting and detachment are repeated during one rotation.

  The invention according to claim 5 is the resin pipe joint according to claim 4, wherein the convex portion 20 and / or the concave portion 19 are formed at equal angles with respect to the axis P in the circumferential direction. To do.

  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 first aspect of the present invention, as will be described in detail in the section of the embodiment, the action of the torque fluctuation portion accompanying the tightening rotation of the union nut, that is, the convex portion and the concave portion are either one of the shafts. The torque fluctuation due to the fitting and disengaging with each other due to the bending displacement in the center direction becomes large, and it is possible to clearly sense the torque fluctuation through a tool (spanner, wrench, etc.) that rotates the union nut. Therefore, since a large torque fluctuation occurs when the end or end of tightening approaches, it is possible to recognize that the end of tightening or almost end of the union nut with an operational feeling. As a result, it is possible to confirm that the union nut has been tightened or close to it even at work sites where the pipe joint is not visible or difficult to see, and under noisy conditions. It is possible to provide a resin pipe joint that is improved so as to have excellent workability and handling properties.

  According to claim 2, the convex portion is formed on the outer peripheral flange of the joint body, and the concave portion is formed on the end portion of the union nut on the female screw forming side, so that the convex portion and the outer peripheral flange can be deflected and displaced in the axial direction. A torque fluctuation part can be comprised. According to a third aspect of the present invention, if a protrusion that protrudes radially outward at the protrusion and a protrusion that protrudes radially outward on the axial direction side of the recess are provided, There is an advantage that it can be confirmed whether or not the projecting portion is aligned in the circumferential direction, whether or not the projecting portion is close in the axial direction, that is, whether the tightening is completed or close.

  If a plurality of convex portions and concave portions are formed in the circumferential direction as in claim 4 and the engagement and disengagement during one rotation of the union nut are repeated, the frequency of the large torque fluctuation described above increases. Thus, there is an advantage that the sensory recognition becomes clearer and the effects of the first to third aspects of the invention are enhanced. In this case, it is preferable that the convex portions and the concave portions are formed at equal angles in the circumferential direction as in the fifth aspect, because a plurality of the fitting and detaching are overlapped to make torque fluctuation more remarkable.

  In addition, if the joint body and the union nut are made of a fluorine-based resin having excellent chemical resistance and heat resistance, the fluid may be a chemical or a chemical liquid, or a high temperature. Even if it is a fluid, the joint structure portion will not be deformed and will not leak easily, and good sealing performance and pull-out resistance can be maintained. Note that the fluorine-based resin is preferable in that it is stable at high temperatures, excellent in water repellency, has a small coefficient of friction, has extremely high chemical resistance, and has high electrical insulation.

  Embodiments of a resin pipe joint according to the present invention will be described below with reference to the drawings. 1 to 5 are drawings related to the resin pipe joint according to the first embodiment, and FIGS. 6 to 8 are drawings related to the resin pipe joint according to the second embodiment.

[Example 1]
As shown in FIG. 1, the resin pipe joint A according to Example 1 is made of a tube 3 made of fluororesin (an example of synthetic resin represented by PFA, PTFE, etc.), a fluid device such as a pump, a valve, The joint body 1 is made of a fluorine resin (an example of a synthetic resin represented by PFA, PTFE, etc.) and a fluorine resin (an example of a synthetic resin, represented by PFA, PTFE, etc.). It consists of two parts with the union nut 2 made. FIG. 1 shows a tightening end state (assembled state) in which the union nut 2 is tightened by a predetermined amount.

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

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

  The cut surface 16 is formed so that the maximum diameter thereof is a substantially intermediate value between the inner diameter and the outer diameter of the tube 3 in the natural state, but this is not particularly concerned. Further, on the opposite side of the flange 1A in the axial center P direction from the male screw 5, an operation hexagon nut portion 23 having a constant width in the axial center P direction and a subsequent round pipe portion (not shown) are formed. Yes.

  As shown in FIGS. 1, 2, and 4, a convex portion 20 that protrudes in the axial direction is integrally formed on the outer peripheral flange 1 </ b> A. The convex portion 20 includes a main convex portion 20A that protrudes in the direction of the axis P from the side peripheral surface 1a of the outer peripheral flange 1A on the male screw side, and an auxiliary convex portion that protrudes radially outward from the outer peripheral surface 1b of the outer peripheral flange 1A. An example) 20B, and has a certain width d. This convex part 20 is formed in four places for every equal angle of 90 degrees with respect to the axis P.

  1, 3 and 4, the union nut 2 includes a female screw 8 that can be screwed into the male screw 5, and a diameter expansion change region 9 in a diameter expansion portion 3A that is externally fitted to the inner cylinder 4 of the tube 3. Peripheral edge for sealing (an example of a pressing portion for sealing) 10 that can act on the small-diameter side end portion, a retaining peripheral edge 11 that can act on the large-diameter side end portion of the diameter-enlarging change region 9, and the enlarged-diameter portion 3A, a presser inner peripheral portion 13 that can be externally fitted to a diameter-enlarging straight portion 12 that is surrounded by a straight barrel portion 4B having a constant diameter, and a tube 3 that has a predetermined length in the axis P direction following a sealing peripheral edge 10 A guide cylinder portion 14 is provided so as to surround the entire length.

  The sealing peripheral edge 10 has an inner diameter substantially equal to the outer diameter of the tube 3, and the pressing surface 10 a is a side peripheral surface orthogonal to the axis P. The diameter of the circumferential edge 11 for retaining is larger than that of the outer peripheral surface 4b of the straight barrel portion 4B whose inner peripheral surface is the maximum diameter of the inner tube 4, and the diameter obtained by adding the wall thickness of the tube 3 That is, although it is set to a value smaller than the diameter of the presser inner peripheral portion 13, it may not be so (for example, a smaller diameter than the outer peripheral surface 4 b), and if it acts on the large diameter side portion of the diameter expansion change region 9. good. The pressing surface 11a of the retaining peripheral edge 11 is also a side peripheral surface orthogonal to the axis P.

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

  As shown in FIGS. 1, 3, and 4, a concave portion 19 that is recessed in the axial direction so as to be fitted into the convex portion 20 of the joint body 1 is provided at the female screw side end of the union nut 2. An arc projection 18 projecting in the direction of the axis P having an outer diameter equivalent to the outer diameter of the union nut 2 and an inner diameter slightly larger than the diameter of the screw bottom of the female screw 8 is formed on the female screw side end. It is formed at a total of eight locations for each uniform angle (45 degrees), and a recess 19 is formed between the arc projections 18 adjacent to each other in the circumferential direction. In other words, the recesses 19 are formed at eight locations for every 45 degrees of equal angle with respect to the axis P. Further, on the outer peripheral surface 2A of the union nut 2, a protruding portion 24 having the same width (circumferential length) as that of the concave portion 19 and extending in the axial direction and slightly protruding radially outward is provided in the concave portion 19 in the axial direction. Are formed at eight locations in adjacent portions (see FIG. 3A).

  Next, in order to externally insert the end of the tube 3 into the inner cylinder 4, the tube 3 is forcibly pushed in at room temperature to increase the diameter, or it is warmed using a heat source so as to be easily deformed by expansion. The tube end 3t is formed as a cover tube as shown in FIG. 1 by pushing it into the inner tube 4 after expanding the tube end in advance using a diameter expander (not shown). Insert until the end wall 15 of the portion 6 is located inward. As shown in FIGS. 1 and 2, the enlarged diameter portion 3A that is externally fitted to the inner cylinder 4 includes an enlarged diameter changing region 9 that is fitted externally to the outer peripheral surface 4a of the tapered tip portion 4A, and a straight body. It consists of the diameter-expanded straight part 12 fitted on the outer peripheral surface 4b of the cylinder part 4B.

  That is, as shown in FIGS. 1 and 2, the shaft center 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 in which the tube 3 is fitted on the inner cylinder 4. Due to the screwing in the P direction, 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 formed. It is set so that it is pressed in the axis P direction by the circumferential edge 11 for retaining, and the small diameter side portion of the diameter change region 9 is pressed in the axis P direction by the sealing 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 in the direction of the axis P (see FIG. 2 and the like), but if the angle of the outer peripheral surface 4a becomes steep, the separation distance is expanded, If it becomes loose, 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 inner tube 4 without any fluid such as cleaning liquid or chemical solution entering between the inner tube 4 and the enlarged diameter portion 3A.

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

  If the diameter-enlarged portion 3A is displaced in the axial center P direction even a little, the seal point in the seal portion S may be shifted and the seal function may be uncertain, but this is prevented in advance. Accordingly, the retaining means N is configured in which the movement of the diameter-enlarged portion 3A in the direction of coming out of the inner cylinder 4 in the direction of the axis P is firmly restricted, thereby realizing an excellent pull-out resistance. As a result, the flare-type resin pipe joint A composed of the joint body 1 and the union nut 2 can be easily assembled by nut operation in a state where the tube is attached to the inner cylinder, and has excellent assemblability. It has been realized as an improved product that can achieve both excellent sealing performance by the seal portion S and excellent pull-out resistance by the retaining means N.

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

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

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

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

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

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

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

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

  This resin pipe joint A informs the operator with an operational sensation that the end or end of tightening of the union nut 2 in the assembly work state in which the tube 3 is inserted and fixed with the union nut 2 is approaching. Tightening end recognition means C is provided. As shown in FIGS. 1 to 5, the tightening end recognition means C is formed on the convex portion 20 formed on the flange 1 </ b> A of the joint body 1 and on the tip side of the union nut 2 (on the side of the female screw 8). This is configured by providing a torque fluctuation portion 26 composed of the aforementioned concave portion 19.

  FIG. 1 shows an assembled state as a pipe joint in which four protrusions 20 correspond to four recesses 19 corresponding to a predetermined length in the direction of the axis P, and the axis in the plane of FIG. On the lower side from P, a portion where the side peripheral surface 1a of the outer peripheral flange 1A and the arc projection 18 face each other is drawn. In this assembled state, there is a gap in the direction of the axis P between the side peripheral surface 18a at the tip of the arc protrusion 18 and the side peripheral surface 1a of the outer peripheral flange 1A, and the axis P direction is more than that gap. A gap having a large length is formed between the convex portion 20 and the concave portion 19.

  Next, the operation of the torque fluctuation unit 26 will be described. When the union nut 2 screwed on the joint body 1 is turned and screwed, the arc projection 18 gradually approaches the outer peripheral flange 1A as shown in FIG. 4 (a). When the tightening rotation of the union nut 2 is continued, as shown in FIG. 4B, the contact surfaces 20a of the four convex portions 20 corresponding to the tip surfaces 18a of the four arc projections 18 out of the eight locations ( It comes into contact with the side surface of the main convex portion 20A at a gentle incident angle (an angle resulting from the pitch of the male screw 5 and the female screw 8).

  Still further, when the union nut 2 is turned in the tightening direction, each arc projection 18 pushes the projection 20 in the direction of the axis P to bend and deform the projection 20 and the outer peripheral flange 1A (see FIG. 5). 4 can pass through the convex portion 20, and the convex portion 20 approaching the next concave portion 19 can be restored and displaced to the original posture, resulting in a state of entering the concave portion 19 as shown in FIG. That is, as shown in FIG. 5, the outer peripheral flange 1A that seems to be in a cantilevered state on the inner periphery and is relatively deformed turns over with the convex portion 20 that receives the force in the axial center P direction. As shown in FIG. 4 (c), the four concave portions 19 corresponding to the respective convex portions 20 are displaced from each other. It fits in.

  In other words, the fact that the eight arc projections 18 for forming the concave portion 19 and the four convex portions 20 interfere with the turning operation of the union nut 2 is the axis of the convex portion 20 and the outer peripheral flange 1A at that portion. The displacement is caused by the deflection displacement in the direction of the center P. For that purpose, the deflection 20 and the deflection displacement in the direction of the axis P of the outer peripheral flange 1A (see FIG. 5), and the subsequent projection 20 and the recess 19 The fitting, that is, the restoring displacement of the convex portion 20 and the outer peripheral flange 1A at that portion will be repeated thereafter. When the arcuate protrusion 18 interferes with the convex part 20, each edge 10, 11 is bitten into the enlarged diameter part 3A to some extent, that is, tightening by turning the union nut 2 to finish the assembly of the resin pipe joint A. (Screwing) is almost complete.

  In short, the resistance when the four convex portions 20 and the outer peripheral flange 1A of the portion are bent and displaced so as to fall in the direction of the axis P becomes the strong rotational resistance of the union nut 2, and the torque fluctuation (torque increase) is. It is clearly transmitted to the fingers through a tool such as a spanner or a wrench that operates the hexagon nut 2b. As the union nut 2 is turned in, the fitting length of the convex portion 20 and the concave portion 19 in the direction of the axis P increases (the amount of interference between the arc projection 18 and the convex portion 20 in the axis P direction). The deflection displacement of the convex portion 20 and the outer peripheral flange 1A for dodging the interference between the arc projection 18 and the convex portion 20 becomes remarkable, and the clear torque fluctuation itself gradually increases. It is possible for the operator to know sensuously and surely that the tightening operation No. 2 has been completed or is nearing the end.

  That is, the convex part 20 which protrudes in the axial center P direction formed in the outer peripheral part of 1 A of flanges of the coupling main body 1, and the recessed part 19 which is recessed in the axial center P direction formed in the axial center P direction edge part of the union nut 2. However, due to the tightening rotation from near the end of screwing of the union nut 2 when the sealing pressing portion 10 presses the diameter expansion change region 9, the convex portion 20 and the axial flange P direction of the outer peripheral flange 1A at that portion are rotated. A torque fluctuation portion 26 that is fitted and detached from each other is formed by the bending displacement, and the tightening end recognition means C is constituted by the presence of the torque fluctuation portion 26.

  In the torque fluctuation portion 26, an auxiliary convex portion 20B that protrudes radially outward from the outer peripheral surface 1b of the outer peripheral flange 1A is formed on the convex portion 20, and the portion adjacent to the concave portion 19 of the union nut 2 in the direction of the axis P is radially outward. A projecting portion 24 is formed so as to project. Thereby, for example, when the pipe joint A is disposed at a place where it is difficult to see, the auxiliary convex portion 20B and the protruding portion 24 having the same diameter are aligned in the circumferential direction by touching with fingers. It is easy to recognize whether it is in the state [the state of FIG. 4C] and whether it is very close in the direction of the axis P. That is, it is possible to confirm whether or not the recessed portion 19 and the projecting portion 20 are assembled with each other with a fingertip sense as compared with the case where the auxiliary projecting portion 20B and the projecting portion 24 are not provided. There are easy advantages.

  Due to the large torque fluctuation caused by the torque fluctuation section 26, even if a tool such as a wrench is used, the operator's fingers are touched by a "feeling" when the union nut 2 is turned, that is, a feeling corresponding to a feeling of moderation by the detent mechanism. Is clearly communicated, so that the end of tightening can be recognized. In the resin-sensed joint A of Example 1 in which the concave portions 19 exist at eight locations, the union nut 2 may be stopped when the six “crimping feelings” including the first clear “crimping feeling” are recognized. In some cases, the assembly state (tightening end state) shown in FIG. 1 or FIG.

  Next, tightening of the union nut 2 will be described. The resin pipe joint A is set so that the union nut 2 can be slightly tightened to compensate for a decrease in the holding force of the tube 3 over time. That is, in the assembled state (see FIGS. 1 and 4C), there is a gap in the direction of the axis P between the side peripheral surface 1a of the outer peripheral flange 1A and the side peripheral surface 18a of the arc projection 18. Accordingly, the clearance can be further tightened by further turning the union nut 2.

  If both side peripheral surfaces 1a and 18a come into contact with each other, the union nut 2 cannot be tightened any more and the final tightening state is reached. By being in the final tightening state, there is an advantage that it is possible to prevent breakage of the pipe joint A such as screw jump of the male screw 5 and the female screw 8 and neck breakage. Further, the concave portion 19 penetrates in the radial direction (see FIG. 3B), and the fitting state with the convex portion 20 can be visually observed. For example, if the recess 19 and the protrusion 20 are in contact with each other in the direction of the axis P before the arc protrusion 18 and the outer peripheral flange 1A are in contact with each other, the final tightening state can be visually confirmed.

[Example 2]
The resin pipe joint A according to the second embodiment is the same as the resin pipe joint A according to the first embodiment except for the structure of the torque fluctuation portion 26. Therefore, only the different torque fluctuation section 26 will be described. As shown in FIGS. 6-8, the torque fluctuation | variation part 26 of Example 2 is a union in the state which does not penetrate the four convex parts 20 which have an outer diameter smaller than the outer diameter of 1 A of outer peripheral flanges, and a diameter outer side. This is a structure composed of eight recesses 19 formed at the female screw side end of the nut 2.

  That is, as shown in FIG. 8, the concave portion 19 (see FIG. 3 and the like) in the union nut 2 of the first embodiment is covered with the protruding portion 24 that extends in the axis P direction. Accordingly, as shown in FIG. 6C, the portion of the convex portion 20 that enters the concave portion 19 is not visible from the outside (not limited to this as long as the union nut 2 is made of a resin material that can be seen through).

  FIGS. 6A to 6C show the assembly operation of the resin pipe joint A of the second embodiment. 6 (a) and 6 (b) are the same as those in the first embodiment shown in FIGS. 4 (a) and 4 (b). In the tightening end state (assembled state) shown in FIG. 6C, it can be seen that the tip portion of the convex portion 20 in the direction of the axis P is fitted in the concave portion 19 that cannot be seen from the outside of the diameter. It can also be seen from FIG. 6 that the projecting portion 24 extends to the end of the union nut 2.

[Another Example]
The number of the recessed parts 19 should just be more than the number of the convex parts 20, and the convex part 20 should just be one or more. Although not shown in the drawings, torque fluctuation formed by disposing a concave portion recessed in the axial center P direction on the outer peripheral flange 1A and a convex portion projecting in the axial center P direction at the end portion of the union nut 2 in the axial center P direction. The part 26 can also be configured. In addition, the present invention is applied to a joint having a structure in which a tube expanded portion is fitted in a fitting cylinder using an inner ring, that is, a resin pipe joint composed of a union nut, a joint body, and an inner ring. Also good.

Sectional drawing which shows the structure of the resin pipe joint by Example 1 Sectional view showing the structure of the flange part of the joint body The end of the union nut is shown, (a) is an axial direction view, (b) is a partial bottom view. 1 shows the assembly operation of the joint of FIG. 1, (a) is a state where the concave portion and the convex portion are spaced apart, (b) is a state where the tip of the union nut is in contact with the outer peripheral flange, and (c) is a convex portion of the concave portion. Assembly state with part fitted Action diagram showing the situation where the outer peripheral flange is bent by being pushed by the remaining peripheral part (A) is a state where the concave portion and the convex portion are separated from each other, (b) is a state where the tip of the union nut is in contact with the outer peripheral flange, and (c) is a state where the resin pipe joint of Example 2 is assembled. A state in which the convex portion is fitted in the concave portion Sectional drawing which shows the structure of the flange part of the coupling main body in FIG. Axial direction view showing the recess of the union nut in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Joint main body 1A Outer peripheral flange 1b Outer peripheral surface of outer peripheral flange 2 Union nut 3 Tube 3A Expanded diameter part 4 Fitting cylinder 5 Male thread 8 Female thread 9 Expanded diameter change area 10 Sealing pressing part 19 26 Torque fluctuation part P Shaft center 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 convex portion projecting in the axial direction and a concave portion recessed in the axial direction so as to be fitted thereto are distributed and arranged between the outer peripheral portion of the joint body and the outer peripheral portion of the axial end portion of the union nut, The convex portion and the concave portion are moved in the direction of one of the axes along with the tightening rotation from near the end of screwing of the union nut when the sealing pressing portion presses the diameter change region. A resin pipe joint in which torque varying portions that are fitted and detached from each other by bending displacement are configured.   The convex portion is formed on the outer peripheral flange of the joint body, and the concave portion is formed on the end of the union nut on the female screw forming side, and the convex portion and the outer peripheral flange can be deflected and displaced in the axial direction. The resin pipe joint according to claim 1, which is configured as follows.   A protruding portion that protrudes radially outward from the outer peripheral surface of the outer peripheral flange is formed on the convex portion, and a protruding portion that protrudes radially outward is formed in a portion adjacent to the concave portion of the union nut in the axial direction. The resin pipe joint according to claim 2.   The said convex part and / or the said recessed part are formed in multiple numbers in the circumferential direction, and it is comprised so that the said fitting and detachment may be repeated while the said union nut is rotated once. The resin pipe joint according to one item.   The resin pipe joint according to claim 4, wherein the convex part and / or the concave part are formed at equal angles with respect to the axis in the circumferential direction.   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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