JP5075800B2 - Resin pipe fitting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin pipe joint improved to be excellent in assembly workability and handling properties to confirm that fastening a union nut is ended or almost ended even when a pipe joint is placed in invisible or less visible place or 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 into an inner cylinder 4 to form a diameter-enlarged part 3A, and a diameter-enlarged change region 9 is thrust by a sealing thrusting part 10. In addition, there is provided a torque changing part 26 where a projection 20 of a joint body 1 and a recess 19 of the union nut 2 overleap when either of a first protruded ridge 19 and a second protruded ridge 20 is bent and displaced by tightening the rotation just before the end of advancing of the union nut 2 by pressing the diameter-enlarged change region 9 via the sealing thrusting part 10. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

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

  As this type of resin pipe joint, a tube joint disclosed in Patent Document 1 is known. That is, the tube (1) made of synthetic resin is forcibly pushed into the 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 assembling workability and handling.

The invention according to claim 1 is a synthetic resin joint body 1 including a fitting cylinder 4 that can be fitted and mounted by expanding the end of the synthetic resin tube 3, and a male screw 5, and
A union nut 2 made of a synthetic resin including a female screw 8 that can be screwed into the male screw 5 and a sealing pressing portion 10 that can act on a diameter expansion change region 9 in the diameter expansion portion 3A of the tube 3;
The union nut 2 is screwed in the axial direction P of the joint body 1 by screwing the female screw 8 into the male screw 5 in a state in which the tube 3 is fitted and attached to the fitting cylinder 4. In the resin pipe joint configured such that the expanded diameter change region 9 is pressed in the axial center P direction by the sealing pressing portion 10 to form the sealing portion S.
A first protrusion 19 projecting toward the radially inner side and extending in the circumferential direction is disposed at an end portion of the union nut 2 in the axial center P direction , and projects toward the radially outer side and extends in the circumferential direction. Article 20 is deployed on the outer periphery of the joint body 1, with the tightening rotation from the vicinity of the screwing ends short of the union nut 2 of the sealing pressing portion 10 presses the diameter change region 9 Thus, a torque fluctuation portion 26 is constructed in which the first ridge 19 and the second ridge 20 are able to overcome each other by their one deflection displacement,
Wherein the first projection 19, and the female screw 8, is arranged between the tip in the axial direction P end of the union nut 2, the inner inclined side peripheral surface 19a of the female thread side, of the distal-side An outer inclined side peripheral surface 19b, and the second protrusion 20 is disposed between the male screw 5 and an outer peripheral flange 1A formed on the joint body 1, and has a front inclined circumference on the male screw side. It has a side surface 20a and a back inclined peripheral side surface 20b on the outer peripheral flange side.

  The invention according to claim 2 is the resin pipe joint according to claim 1, wherein the first protrusion 19 and / or the second protrusion 20 are formed in an annular protrusion over the entire circumference. To do.

  According to a third aspect of the present invention, in the resin pipe joint according to the first or second aspect, the first protrusion 19 is formed on an inner peripheral portion of the female thread forming side end portion of the union nut 2, and the second protrusion The strip 20 is formed on the outer periphery of the joint body 1.

According to a fourth aspect of the present invention, in the resin pipe joint according to the third aspect, the second protrusion 20 is disposed close to the male thread forming side of the outer peripheral flange 1A. is there.

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

  According to the invention of claim 1, the details will be described in the section of the embodiment, but the action of the torque fluctuation portion accompanying the tightening rotation of the union nut, that is, the first protrusion and the second protrusion are those. The torque fluctuation due to overcoming each other by one bending displacement becomes large, and the torque fluctuation can be clearly sensed through a tool (spanner, wrench, etc.) that turns 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.

  If the first and second ridges are annular ridges over the entire circumference as in claim 2, the torque fluctuation of the torque fluctuation portion becomes larger, and the effect of the invention of claim 1 is enhanced. There are advantages. And, as in claim 3, the first protrusion is formed on the inner peripheral part of the female thread forming side end of the union nut, and the second protrusion is formed on the outer peripheral part of the joint body, respectively. Thus, the 2nd protrusion can be arranged near the external thread formation side of the peripheral flange of a joint main part.

  Further, 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 liquid 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. Fluoropolymers are preferred because they are stable at high temperatures, have excellent water repellency, have a low coefficient of friction, have extremely high chemical resistance, and high electrical insulation.

  Embodiments of a resin pipe joint according to the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a resin pipe joint according to the first embodiment, FIG. 2 is an operation diagram showing an assembly state of the joint of the first embodiment, and FIG. 3 is an operation diagram showing an assembly state of the joint of the second embodiment. 2 and 3, the tube is omitted, and the joint body and the union nut are simplified to some extent.

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

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

  The cut surface 16 is formed so that the maximum diameter thereof is a substantially intermediate value between the inner diameter and the outer diameter of the tube 3 in the natural state, but this is not particularly concerned. Further, on the 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 and 2, a second protrusion 20 is formed on the male thread side portion of the outer peripheral flange 1 </ b> A (the outer peripheral portion of the joint main body) so as to protrude outward in the radial direction and extend in the circumferential direction. The second protrusion 20 has a front inclined peripheral side surface 20a on the male screw side and a back inclined peripheral side surface 20b on the flange side, and has a substantially equilateral triangle in cross section. As the protrusions, the joint body 1 is integrally formed at a position away from the outer peripheral flange 1A by the length d in the axis P direction. The outer diameter of the second protrusion 20 is slightly smaller than the outer diameter of the outer peripheral flange 1A.

  As shown in FIGS. 1 and 3, the union nut 2 includes a female screw 8 that can be screwed to the male screw 5, and a small diameter side of a diameter expansion change region 9 in a large diameter portion 3 </ b> A that is externally fitted to the inner cylinder 4 of the tube 3. A peripheral edge for sealing (an example of a pressing portion for sealing) 10 that can act on the end portion, a circumferential edge 11 for retaining that can act on the large-diameter side end portion of the diameter expansion change region 9, and a diameter in the expanded diameter portion 3A The presser inner peripheral portion 13 that can be externally fitted to the diameter-enlarging straight portion 12 that is surrounded by a certain straight barrel portion 4B, and the tube 3 is placed over a predetermined length in the axis P direction following the sealing peripheral edge 10. And a guide cylinder portion 14 that surrounds the guide cylinder portion 14.

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

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

  As shown in FIGS. 1 and 2, a first protrusion 19 that protrudes inward in the radial direction and extends in the circumferential direction is formed at the female screw side end of the union nut 2. The first protrusion 19 has an inner inclined side peripheral surface 19a on the female screw side and an outer inclined side peripheral surface 19b on the distal end side, has a substantially equilateral triangle in section, and is an endless annular one that makes a round in the circumferential direction. As the (annular protrusion), a protrusion is formed from the tip of the union nut 2. The diameter of the straight cylindrical guide inner peripheral surface 25 formed on the inner back side of the first protrusion 19 is equal to or slightly larger than the maximum outer diameter of the second protrusion 20. In addition, the diameter of the guide outer peripheral surface 24 between the second protrusion 20 and the outer peripheral flange 1 </ b> A is equal to or slightly smaller than the minimum inner diameter of the first protrusion 19.

  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 tips the front-end | tip 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-enlarging 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 the subsequent tightening completion state (assembled state) and is excellent in convenience is 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 and 2, the tightening end recognizing means C is accompanied by the tightening rotation from the vicinity of the end of the union nut 2 before the end of screwing, when the sealing peripheral edge 10 presses the diameter change region 9. Thus, the first protrusion 19 and the second protrusion 20 are configured by providing a torque fluctuation portion 26 that can be overcome by one or both of the deflection displacements.

  FIG. 1 shows a state immediately after the first protrusion 19 has passed over the second protrusion 20 due to screwing associated with the tightening of the union nut 2, that is, a tightening end state (assembled state) as the resin pipe joint A. Show. As the tightening end state, the inner inclined side peripheral surface 19a of the first protrusion 19 and the back inclined peripheral side surface 20b of the second protrusion 20 are in contact with each other, but may be slightly separated from each other.

  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 first protrusion 19 gradually approaches the second protrusion 20 as shown in FIG. A state is brought about in which the inclined peripheral side surface 19b and the front inclined peripheral side surface 20a come into contact with each other. When the tightening rotation of the union nut 2 is continued, the outer inclined peripheral side surface 19b and the front inclined peripheral side surface 20a are strongly pressed in the direction of the axis P, and the inclined component force of each of the inclined surfaces 19b and 20a causes FIG. As shown in b), the first protrusions 19 having relatively weak strength and rigidity are bent outwardly and deformed together with the outer peripheral cylindrical portion 2T supporting the first protrusions 19T.

  Still further, when the union nut 2 is turned in the tightening direction, the first protrusions 19 and the distal end portions of the outer peripheral cylindrical portion 2T are greatly expanded to the outside of the diameter so that the second protrusions 20 can be passed over. And the front-end | tip part of the outer periphery cylinder part 2T can be restored-displaced to the original attitude | position, and as shown in FIG.2 (c), the fastening completion state which the 1st protrusion 19 overcame the 2nd protrusion 20 is obtained.

  That is, the interference between the first protrusion 19 and the second protrusion 20 with the turning operation of the union nut 2 is caused by the deflection displacement of the first protrusion 19 and the distal end portion of the outer peripheral cylindrical portion 2T toward the radially outer side. Therefore, the displacement of the first protrusion 19 and the distal end of the outer peripheral cylindrical portion 2T to the outside of the diameter (see FIG. 2B), and the subsequent first protrusion 19 and the distal end of the outer peripheral cylindrical portion 2T. Restoration displacement of the part causes intense torque fluctuation. When the first ridge 19 gets over the second ridge 20, the union nut 2 is turned so that the edges 10 and 11 bite into the expanded diameter portion 3A to some extent, that is, the assembly of the resin pipe joint A is completed. All tightening (screwing) is almost complete.

  In short, the resistance when the first protrusion 19 and the distal end portion of the outer peripheral cylindrical portion 2T are deflected and displaced outwardly becomes the strong rotation resistance of the union nut 2, and the torque fluctuation (torque increase) causes the hexagon nut portion 2b to move. It is clearly transmitted to the fingers through the tool such as a spanner or a wrench to be operated, and the operator senses that the tightening operation of the union nut 2 has come to an end or close by recognizing the clear torque fluctuation. It is possible to know with certainty.

  That is, the first protrusion 19 that protrudes toward the inner diameter and extends in the circumferential direction, and the second protrusion 20 that protrudes toward the outer diameter and extends in the circumferential direction are the ends of the union nut 2 in the axis P direction. The first protrusion is provided along with the tightening rotation of the union nut 2 near the end of screwing when the seal peripheral edge 10 presses against the diameter expansion change region 9 and is distributed to the outer peripheral portion of the joint body 1. A torque fluctuation portion 26 is formed in which the strip 19 and the second protrusion 20 can overcome each other by one of the deflection displacements, and the tightening end recognition means C is configured by the presence of the torque fluctuation portion 26. .

  In the torque fluctuation part 26, since the 1st protrusion 19 expand | swells to a diameter outer side largely, and it deform | transforms, the 2nd protrusion 20 is passed over, For example, the pipe joint A is felt by the touch by touching the 1st protrusion 19 with a finger. Even when it is arranged at a place where it is difficult to see, it is possible to recognize whether or not it is in a tightening end state as a pipe joint. Further, an impact sound may be generated due to a sudden return deformation when the first protrusion 19 passes over the second protrusion 20, and it is possible to recognize that the tightening is finished by the impact sound. In other words, if a large torque fluctuation is felt on the fingers turning the union nut 2 or if an impact sound is heard, the turning operation of the union nut 2 may be stopped. At that time, the assembly shown in FIG. 1 and FIG. It is set to obtain the state (tightening end state). In addition, it is possible to recognize that the tightening has been completed by visual confirmation that the first protrusion 19 covers the second protrusion 20.

  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. In other words, in the assembled state (see FIGS. 1 and 2C), there is a gap e in the direction of the axis P between the tip side peripheral surface 2a of the union nut 2 and the side peripheral surface 1a of the outer peripheral flange 1A. ing. Accordingly, the clearance e can be further tightened by further turning the union nut 2. If both the peripheral surfaces 1a and 2a come into contact with each other, the union nut 2 cannot be tightened any further 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.

[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 FIG. 3, the torque fluctuation portion 26 according to the second embodiment has a structure in which two sets of first protrusions 19 and 19 are connected in the direction of the axis P.

  That is, the first ridge 19 on the distal end side of the union nut 2 is for constituting the torque fluctuation portion 26 for the tightening end recognition means C, and exhibits the same function and effect as in the first embodiment. The second first ridge 19 constitutes a torque changing portion 26 for tightening in cooperation with the second ridge 20 for the tightening end recognition means C.

  That is, the additional tightening is finished when the union nut 2 is further turned from the tightening end state shown in FIG. That is, when the first large torque fluctuation is passed, the tightening is finished, and when the torque fluctuation (total torque fluctuation for the second time) is felt by the subsequent union nut 2 turning operation, the additional tightening operation is finished. It is possible to recognize the completion of tightening with an operational feeling. Of course, the completion of the tightening can be recognized by recognizing the impact sound when getting over.

[Another Example]
The first ridges 19 and the second ridges 20 may be arcuate parts divided in the circumferential direction, or a plurality of them may be formed. Moreover, the cross-sectional shape of these protrusions 19 and 20 may be arcuate or trapezoidal, and is not limited to a triangle . Also, the present invention, joint structures tube enlarged diameter portion with an inner ring is fitted into the fitting tube, i.e., the union nut, the coupling body, is applied to the resin pipe joint made of 3 parts of the inner ring May be.

Sectional drawing which shows the structure of the resin pipe joint by Example 1 1 shows the assembly operation of the joint of FIG. 1, (a) is a state where the first and second ridges are separated from each other, and (b) is a state where the first ridge is in contact with the second ridge. , (C) is the tightening completed state where the first protrusion has overcome the second protrusion. The assembling action of the resin pipe joint according to Example 2 is shown, (a) shows a state where the first and second ridges are separated from each other, and (b) shows that the first and second ridges hit the second ridge. (C) is the tightening completed state where the first ridge overcame the second ridge.

DESCRIPTION OF SYMBOLS 1 Joint body 1A Outer flange 2 Union nut 3 Tube 3A Expanded diameter part 4 Fitting cylinder 5 Male thread 8 Female thread 9 Expanded diameter change area 10 Sealing pressing part 19 First protrusion 19a Inner inclined side peripheral surface 19b Outer inclined side peripheral surface 20 2nd protrusion 20a Front inclined peripheral side surface 20b Back inclined peripheral side surface 26 Torque variation part P Axis center S Seal part

Claims (5)

A synthetic resin joint body comprising a fitting tube that can be fitted and mounted by expanding the end of the synthetic resin tube, and a male screw, and
A union nut made of a synthetic resin provided with a female screw that can be screwed into the male screw, and a sealing pressing portion that can act on a diameter expansion change region in the diameter expansion portion of the tube;
As the union nut is screwed in the axial direction of the joint main body by screwing the female screw with the male screw in a state where the tube is fitted and attached to the fitting cylinder, the diameter expansion change region is A resin pipe joint configured to be pressed in the axial direction by a pressing portion for sealing to form a sealing portion,
Protrudes toward the radially inner side a first collision condition extending in a circumferential direction, said deployed in the axial direction end portion of the union nut, and a second protrusion extending protrudes toward the radially outer side in the circumferential direction, wherein The first protrusion and the first protrusion are disposed on the outer peripheral portion of the joint body, and the sealing protrusion is tightened and rotated from near the end of screwing of the union nut when the diameter-enlargement change region is pressed. A torque fluctuation portion is formed in which the second ridge can overcome each other by the deflection displacement of one of them,
Wherein the first projection includes: the female thread, the disposed between the tip of the axial end portion of the union nut, the inner inclined side peripheral surface of the female thread side, an outer inclined side peripheral surface of the distal-side The second protrusion is disposed between the male screw and an outer peripheral flange formed on the joint body, and has a front inclined peripheral side surface on the male screw side and a back inclined surface on the outer peripheral flange side. A resin pipe joint having a peripheral side surface.   The resin pipe joint according to claim 1, wherein the first protrusion and / or the second protrusion is formed in an annular protrusion extending over the entire circumference.   3. The resin pipe according to claim 1, wherein the first protrusion is formed on an inner peripheral portion of an end portion of the union nut on the female screw forming side, and the second protrusion is formed on an outer peripheral portion of the joint body. Fittings. 4. The resin pipe joint according to claim 3, wherein the second protrusion is disposed in proximity to a male thread forming side of the outer peripheral flange.   The resin pipe joint according to any one of claims 1 to 4, wherein the joint body and the union nut are made of a fluororesin.

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