JP5124523B2 - Resin pipe fitting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin pipe joint improved to be excellent in assembling performance, and handleability by confirming that the tightening of a union nut is ended or is almost ended even if a pipe joint is placed in a noisy site. <P>SOLUTION: In the resin pipe joint, the union nut 2 advances by screwing a male screw 5 into a female screw 8 with a tube 3 externally fitted to an inner cylinder 4 to form a diameter-enlarged part 3A, and a diameter-enlarged change region 9 is thrust by a seal thrusting part 10. A fragile part 20 is formed at an inner side of an axis P direction of a nut end 19 which is broken when turning torque exceeding the prescribed value is applied, and a fastening end notifying means C is provided which is set so that, when the fragile part 20 is broken by an increase in the torque caused by the fitting of a fitting part 26 and a fitted part 18 by turning the union nut 2 to a fastening direction, the seal thrusting part 10 thrusts the diameter-enlarged change region 9, and the union nut 2 is in an advance end state that a seal part S is formed. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention is also suitable for piping of high-purity liquid and ultrapure water handled in manufacturing processes in various technical fields such as semiconductor manufacturing, medical / pharmaceutical manufacturing, food processing, chemical industry, etc., and includes pumps, valves, filters, etc. The present invention relates to a resin pipe joint used as a connecting means for a tube which is a fluid device or a fluid transfer path.

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

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

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

  Therefore, in Patent Document 3, a projecting piece (15) projecting in the axial direction in a cantilevered state on the joint body (1), and a protrusion formed on the end of the union nut (2) in the axial direction ( When the union nut (2) is about to end tightening, it comes into close contact with each other in the circumferential direction and comes into contact with it. A technique is disclosed that makes it possible to know that the person is approaching. That is, it is a sound generating means that informs the operator of the tightening end state by sound.

Noto 3041899 gazette Japanese Patent Laid-Open No. 7-27274 Japanese Patent Laid-Open No. 11-230463

  Even if the pipe joint portion is not visible, the sound generating means enables confirmation by the sound recognition of the tightening end state by the union nut operation, and a certain effect can be obtained. However, the actual piping work site is rarely in a quiet situation, and it is in a certain level of noise conditions, such as working in a factory that is in operation or other work and construction work being done together Will be done. Therefore, it is often impossible for the operator to hear the sound of the resin protruding piece, and there is still room for further improvement as means for notifying the end of tightening of the union nut, that is, a means for recognizing the end of tightening. It was a thing.

  In view of the above circumstances, the object of the present invention is to make it possible to confirm that the union nut has been tightened or is in a state close to it even in a work site under noise conditions, and to improve workability and handling. It is in providing a resin pipe joint that is improved to be superior.

The invention according to claim 1 is a synthetic resin joint body 1 comprising a fitting tube 4 that can be fitted and mounted by expanding the diameter of an end of the synthetic resin tube 3, and a male screw 5, and
A union nut 2 made of a synthetic resin including a female screw 8 that can be screwed into the male screw 5 and a sealing pressing portion 10 that can act on a diameter expansion change region 9 in the diameter expansion portion 3A of the tube 3;
The union nut 2 is screwed in the 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.
The union nut 2 includes a nut main body 2A having a main body side circumferential portion 2c, and is positioned on the lower side in the screwing direction to the joint main body 1 with respect to the nut main body 2A and has a ring-shaped tip side circumferential shape. A nut tip 19 having a portion 24;
An engaging portion 26 provided on the nut tip 19 and an engaged portion 18 provided on the outer peripheral flange 1A formed on the joint body 1 in a state of facing the nut tip 19 are engaged in the screwing. A rotation prevention mechanism D that engages with each other as the distance between the nut tip portion 19 and the outer peripheral flange 1A approaches the axial center P direction and disables relative rotation in the tightening direction around the axis P. Is configured,
Wherein the screwed directions good side position of the engaging portion 26 of the nut tip 19, the axis weakened portion 20 that breaks with the acts given further rotation torque P around is formed,
When the weakened portion 20 breaks due to a torque increase caused by the engagement of the engaging portion 26 and the engaged portion 18 by rotating the union nut 2 in the tightening direction, the sealing pressing portion 10 Is provided with a tightening end recognizing means C which is set so as to be in a state where the union nut 2 where the seal portion S is formed by pressing the diameter change region 9 is in a screwing end state or just before that.
The fragile portion 20 has a dimension in the axial center P direction between the distal end side circumferential portion 24 of the nut distal end portion 19 and the main body side circumferential portion 2c of the nut body portion 2A that are opposed in the axial center P direction. It is characterized by having and connecting.

  According to a second aspect of the present invention, in the resin pipe joint according to the first aspect, the weakened portion 20 includes a distal-side circumferential portion 24 and a main-body-side circumferential portion 2c that face each other in the axial center P direction. Compared to the distal end side circumferential portion 24 and the main body side circumferential portion 2c, the connecting portion is configured to be integrally connected in a state where the sectional area in the direction of the axis P is extremely small.

  The invention according to claim 3 is the resin pipe joint according to claim 1 or 2, wherein any one of the engaging portion 26 and the engaged portion 18 is a recessed portion recessed in the direction of the axis P. At the same time, one of the engaging portion 26 and the engaged portion 18 is formed on the protruding portion 18 that is convex in the axial direction so as to be able to enter the recessed portion 26. It is characterized by this.

  According to a fourth aspect of the present invention, in the resin pipe joint according to any one of the first to third aspects, the engaging portion 26 and the engaged portion 18 are arranged at every equal angle around the axis P. It is provided in a plurality of places.

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, although described in detail in the section of the embodiment, when the tightening is advanced by turning the union nut by the function of the tightening end recognition means, the engaging portion and the engaged portion are Since the situation where the rotation preventing mechanism is engaged when the two are engaged and the fragile portion is broken immediately thereafter, the rotation torque with respect to the unit tightening amount of the union nut greatly fluctuates. Therefore, since the large torque fluctuation is transmitted to the operator through fingers or the like, it becomes possible to recognize that the union nut tightening state has been reached with an operational feeling. As a result, the resin pipe joint is improved so that it can be confirmed that the union nut has been tightened or is close to it even in a work site under noisy conditions, and the assembly workability and handling are excellent. Can be provided.
In addition, the fragile portion, which is convenient when it is configured to be raised in the axial direction, may be smoothly configured without difficulty to be provided in the union nut that is externally seen in the joint body.

  As the fragile portion, as in claim 2, if the tip-side circumferential portion and the main-body-side circumferential portion facing each other in the axial direction are integrally connected in a state where the cross-sectional area is extremely small, stress concentration It is preferable that it is easy to occur and functions well. Further, if the engaging portion and the engaged portion are the recessed portion and the protruding portion as in claim 3, the rotation prevention mechanism can be configured so that the structure can be simply and reliably functioned by the concave and convex engagement. There are advantages.

  As the rotation prevention mechanism, it is preferable that the engaging portion and the engaged portion are provided at a plurality of positions at equal angles around the axis as in claim 4 in that the operation is stable and balanced. .

According to the invention of claim 5 , the joint body and the union nut are formed of a fluorine-based resin excellent in chemical resistance and heat resistance, and the fluid is a chemical liquid, a chemical liquid, or a high-temperature fluid. Even if it exists, a joint structure part does not deform | transform and does not become easy to leak, but favorable sealing property and drawing-out resistance can be maintained now. A fluorine-based resin is preferable in that it is stable at high temperatures, excellent in water repellency, has a small coefficient of friction, has extremely high chemical resistance, and has high electrical insulation.

Sectional drawing which shows the structure (tightening completion state) of the resin pipe joint by Example 1 Plan view of the resin pipe joint of FIG. Axial direction view of the notch showing the structure of the gauge ring side of the union nut The top view which shows the principal part of the resin pipe joint in the state just before the end of tightening Top view showing the main part of the resin pipe joint in the state before tightening

  Embodiments of a resin pipe joint according to the present invention will be described below with reference to the drawings.

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

  As shown in FIGS. 1 and 2, the joint main body 1 includes 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 It is formed in the cylindrical member provided with the cylindrical fluid-like fluid path 7 having the outer peripheral flange 1A and the like. The inner cylinder 4 has a tapered straight shape having a tapered tip portion 4A for gradually expanding the diameter of the tube 3 and a straight barrel portion 4B formed on the large diameter side of the tapered tip portion 4A. It is structured as a thing.

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

  The cut surface 16 is formed so that the maximum diameter thereof is a substantially intermediate value between the inner diameter and the outer diameter of the tube 3 in the natural state, but this is not particularly concerned. Further, on the side opposite to the male screw 5 in the axial center P direction of the flange 1A, an operation hexagon nut portion 23 having a constant width in the axial center P direction, and a subsequent pipe portion (connecting portion) 25 (FIG. 2). 4 and 5).

  As shown in FIGS. 1 and 2, the joint body 1 includes a mechanism outer peripheral surface 1 c having a diameter equal to or larger than the male thread side surface 1 a of the outer peripheral flange 1 A, and the outer peripheral flange 1 A, and an outer peripheral flange. A protruding portion (an example of an engaged portion) 18 formed on the 1A male screw side surface 1a is formed. The projecting portions 18 are formed at four positions every 90 degrees with the axis P as the center, and project substantially toward the union nut in the direction of the axis P in a substantially rectangular state having a constant width. The outer periphery of each protrusion 18 is flush with the outer peripheral surface of the outer peripheral flange 1A, and the inner periphery is integrated with the mechanism outer peripheral surface 1c.

  As shown in FIGS. 1 and 2, the union nut 2 includes a female screw 8 that can be screwed into the male screw 5, and a small-diameter side of the enlarged-diameter changing region 9 in the enlarged-diameter portion 3 </ b> A that is externally fitted to the inner cylinder 4 of the tube 3. A peripheral edge for sealing (an example of a pressing portion for sealing) 10 that can act on the end portion, a circumferential edge 11 for retaining that can act on the large-diameter side end portion of the diameter expansion change region 9, and a diameter in the expanded diameter portion 3A The presser inner peripheral portion 13 that can be externally fitted to the diameter-enlarging straight portion 12 that is surrounded by a certain straight barrel portion 4B, and the tube 3 is placed over a predetermined length in the axis P direction following the sealing peripheral edge 10. The guide tube portion 14 and the gauge ring portion 19 are formed to be surrounded. In addition, 2A is a nut main-body part by which anti-slip processing was given to the outer periphery, and 2b is a nut part.

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

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

  As shown in FIGS. 1, 3, and 4, the gauge ring portion 19 is formed at the nut tip portion that is the lower side in the screwing direction of the union nut 2 to the joint body, and the end of the nut body portion 2A. A proximal ring portion 24 formed on the circumferential portion 2c via the fragile portion 20, a distal ring portion 27 having a recessed portion 26 engageable with the protruding portion 18, a proximal ring portion 24 and a distal ring portion 27, and a connecting portion 28 that integrally connects to H.27. The connecting portions 28 are formed at a total of four locations for every 90 degrees of equal angle around the axis P, and the depth of the axial direction in which the recessed portions 26 that allow the protrusions 18 to enter reaches the connecting portions 28. In the same manner, four positions are formed for each equal angle of 90 degrees with respect to the axis P.

  The fragile portion 20 includes a proximal ring portion (an example of a distal end side circumferential portion) 24 and an end circumferential portion (an example of a main body side circumferential portion) 2c facing each other in the direction of the axis P. The union nut 2 is integrally formed as a portion having a small cross-sectional area formed at four positions for each degree of equal angle and having a slight dimension in the axis P direction. That is, the fragile portion 20 is formed at a connecting portion that is integrally connected in a state in which the cross-sectional area in the direction of the axis P is significantly smaller than the peripheral portion of the distal end ring portion 24 and the peripheral portion 2c. Yes. The tip surface of the tip ring portion 27 is the end surface 2 a of the union nut 2.

  As shown in FIGS. 2 and 4, a recessed portion 26 that is an engaging portion provided in a gauge ring portion 19 that is a nut tip portion on the lower side in the screwing direction of the union nut 2 to the joint body 1, and a gauge ring The projecting portion 18 which is an engaged portion provided on the outer peripheral flange 1A formed on the joint body 1 in a state of facing the portion 19 is formed between the gauge ring portion 19 and the outer peripheral flange 1A as the union nut 2 is screwed. A rotation prevention mechanism D is configured that engages with each other as the interval between the axial centers P approaches, and disables relative rotation in the tightening direction around the axial center P.

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

  That is, as shown in FIG. 1, in the axial center P direction of the joint body 1 by tightening the union nut 2 by screwing the female screw 8 with the male screw 5 in a state where the tube 3 is externally fitted to the inner cylinder 4. As a result of the screwing, the presser inner peripheral portion 13 is externally fitted to the enlarged diameter straight portion 12, and a portion having a larger diameter than the diameter of the inner cylinder 4 in the larger diameter side portion of the enlarged diameter changing region 9 is used for retaining. The peripheral edge 11 is pressed in the direction of the axis P, and the small diameter side portion of the diameter expansion change region 9 is set to be pressed in the direction of the axis P by the sealing peripheral edge 10. Note that the diameter of the fluid transfer path 3W of the tube 3 and the diameter of the fluid path 7 are set to be the same diameter in order to obtain a smooth fluid flow, but may be different from each other.

  In this case, as described above, there is no gap in the radial direction between the presser inner peripheral portion 13 and the enlarged diameter straight portion 12, and the enlarged diameter straight portion 12 is provided between the straight barrel portion 4B and the presser inner peripheral portion 13. It is in the state where it is clamped. Moreover, in Example 1, the diameter-expansion change area | region 9 of the tube 3 is formed as a part which the front-end | tip narrows and covers 4 A of cylinder parts. The diameter expansion change region 9 is a state of a taper tube that gradually expands, and the sealing peripheral edge 10 and the retaining peripheral edge 11 are in a positional relationship apart from each other in the axis P direction, but the tip tapered tube As the angle of the outer peripheral surface 4a of the portion 4A with respect to the axial center P becomes steeper, the distance in the axial center P direction between the sealing peripheral edge 10 and the retaining peripheral edge 11 becomes closer. Further, the sealing peripheral edge 10 and the tip of the inner cylinder 4 are slightly separated from each other in the direction of the axis P, but if the angle of the outer peripheral surface 4a becomes steep, the separation distance is enlarged, and if it becomes loose, the separation distance. Is reduced.

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

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

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

  Next, the tightening end recognition means C will be described. This resin pipe joint A is a tightening that can be recognized with an operation feeling when the end of tightening of the union nut 2 (or when the end is approaching) in the assembly work state in which the tube 3 is inserted and fixed with the union nut 2 is fixed. Append end recognition means C is provided. That is, as the union nut 2 is turned and tightened, the projecting portion 18 and the recessed portion 26 are fitted and engaged, so that the turning torque acts directly on the fragile portion 20 and finally breaks. In this case, the tightening is completed after the seal portion S is formed. That is, when the operator who operates the union nut 2 feels a large torque fluctuation, the tightening end recognition means C functions such as assembly OK.

  That is, the weakened portion 20 is formed at the upper side of the screw ring direction in the axial center P direction of the recessed portion 26 in the gauge ring portion 19 and breaks when a predetermined or larger rotational torque acts around the axial center P. When the fragile portion 20 is broken due to the torque increase due to the engagement of the recessed portion 26 and the protruding portion 18 by rotating the union nut 2 in the tightening direction, the sealing peripheral edge 10 presses the expanded diameter change region 9. Then, a tightening end recognizing means C is provided which is set so that the union nut 2 in which the seal portion S is formed is in the screwing end state or just before that.

  The operation of the tightening end recognition means C will be described. In a situation where the union nut 2 is tightened and screwed and the circumferential edge 10 for pressing starts to press the diameter change region 9 or immediately before that, FIG. As shown, the protruding portion 18 and the tip ring portion 27 are in a positional relationship that is slightly separated in the direction of the axis P. Further, when the union nut 2 is further tightened and the pressing peripheral edge 10 starts to press the diameter change region 9, as shown in FIG. 4, the protruding portion 18 and the tip ring portion 27 are in the direction of the axis P. Interference occurs, and the protrusion 18 begins to enter the recess 26. By the rotation prevention mechanism D due to the engagement between the projecting portion 18 and the recessed portion 26, the rotation of the union nut 2 relative to the joint body 1 is prevented.

  If the union nut 2 is turned in the tightening direction, the rotational torque also acts on the gauge ring portion 19 via the fragile portion 20, but the gauge ring portion 19 becomes unrotatable by the rotation prevention mechanism D. Therefore, the nut main body 2A continues to rotate while deforming the weakest weak portion 20 in terms of strength. As a result, since the nut main body 2A is continuously rotated, the fragile portion 20 is compressed in the axial center P direction while being largely separated in the circumferential direction while slightly increasing the fitting amount of the protruding portion 18 and the recessed portion 26, In other words, it is greatly twisted, and finally, as shown in FIG. 2, all the four weak portions 20 are broken (in FIG. 2, the boundary between the end circumferential portion 2c and the weak portion 20 is broken). Yes)

  At the moment when the weakened portion 20 breaks and the turning torque of the union nut 2 becomes relatively light, the sealing peripheral edge 10 presses against the diameter-enlargement change region 9 and the union nut 2 is formed so that the seal portion S is formed. It is set to be in the end state. That is, as the union nut 2 is turned, the rotational torque required increases, and when the rotation prevention mechanism D begins to function, the rate of increase in torque increases slightly, but the fragile portion 20 breaks immediately. As a result, a sudden torque decrease occurs in which the rotational torque returns to the original increase rate. Since such a clear torque fluctuation is transmitted to the operator as an operation feeling, the tightening operation may be completed based on this.

  When tightening is started by pushing the tube 3 with the sealing peripheral edge 10, the turning torque (operation torque for turning the union nut in the tightening direction) increases as the union nut is turned, and the turning prevention mechanism When D functions, the rate of increase of the rotation torque, that is, “the increase amount of the rotation torque with respect to the unit rotation operation amount of the union nut 2” increases. When the stress concentrates on the fragile portion 20 and breaks, the rate of increase in rotational torque returns to the state before the function of the rotation prevention mechanism D, and as a result, the rate of increase in rotational torque has suddenly decreased. Thus, a rapid decrease in the rate of increase in rotational torque is transmitted as an operational feeling.

[Another Example]
The rotation prevention mechanism D in which the recessed portion 26 is formed in the outer peripheral flange 1A and the protruding portion 18 is formed in the gauge ring portion 19 may be used .

DESCRIPTION OF SYMBOLS 1 Joint main body 1A Outer peripheral flange 2 Union nut 2c Main body side circumferential part 3 Tube 3A Expanded part 4 Fitting cylinder 5 Male thread 8 Female thread 9 Expanded diameter change area 10 Sealing pressing part 18 Engaged part, projecting part 19 Nut tip Part 20 Fragile part 24 Tip side circumferential part 26 Engagement part, recessed part C Tightening end recognition means D Rotation prevention mechanism P Shaft center S Seal part

Claims (5)

A synthetic resin joint body comprising a fitting tube that can be fitted and mounted by expanding the end of the synthetic resin tube, and a male screw, and
A union nut made of a synthetic resin provided with a female screw that can be screwed into the male screw, and a sealing pressing portion that can act on a diameter expansion change region in the diameter expansion portion of the tube;
As the union nut is screwed in the axial direction of the joint main body by screwing the female screw with the male screw in a state where the tube is fitted and attached to the fitting cylinder, the diameter expansion change region is A resin pipe joint configured to be pressed in the axial direction by a pressing portion for sealing to form a sealing portion,
The union nut has a nut main body portion having a main body side circumferential portion, and a nut tip having a ring-shaped front end side circumferential portion located on the lower side in the screwing direction to the joint main body with respect to the nut main body portion. Department and
An engaging portion provided at the nut tip portion, and an engaged portion provided at an outer peripheral flange formed on the joint body in a state of being opposed to the nut tip portion, the nut tip portion accompanying the screwing, A rotation prevention mechanism is configured that engages with each other as the axial center interval with the outer peripheral flange approaches and disables relative rotation in the tightening direction around the axis,
Wherein the screwed directions good side position of the engagement portion of the nut tip fragile portion to break with the axis given further rotation torque around acts is formed,
When the weakened portion breaks due to a torque increase caused by rotating the union nut in the tightening direction and engaging the engaging portion and the engaged portion, the sealing pressing portion changes in diameter expansion. There is provided a tightening end recognition means that is set so as to be in a state where the union nut of the union nut where the seal portion is formed by pressing an area is set or a state immediately before that
The fragile portion is a resin that connects the tip-side circumferential portion of the nut tip portion and the body-side circumferential portion of the nut main body facing each other in the axial direction with a dimension in the axial direction. Pipe fittings. The fragile portion is, the cross-sectional area in the axial direction when viewed in comparison with the tip-side circumferential portion and said body-side circumferential portion thereof distal end side circumferential portion and the body-side circumferential portion facing in the axial direction The resin pipe joint according to claim 1, wherein the resin pipe joint is configured as a connecting portion that is integrally connected in a state in which is extremely small.   Either the engaging portion or the engaged portion is formed in a recessed portion that is recessed in the axial direction, and the other of the engaging portion and the engaged portion is the recessed portion. The resin pipe joint according to claim 1 or 2, wherein the resin pipe joint is formed on a protruding portion that is convex in the axial direction so as to be able to enter the insertion portion.   The resin pipe joint according to any one of claims 1 to 3, wherein the engaging portion and the engaged portion are provided at a plurality of locations at equal angles around the axis. 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.

Images