JP7370571B2 - Pipe fittings for resin pipes - Google Patents

Description

The present invention relates to a pipe joint for resin pipes for connecting resin pipes.

A resin pipe fitting for connecting resin pipes used in water piping is described in Patent Document 1. The pipe fitting disclosed in the same document has a tapered outer surface part that expands the diameter of the end of the resin pipe, and an in-core that is driven into the resin pipe, and a resin pipe that is inserted into the pipe and reduces its diameter by screwing into the body of the nut. It is equipped with a chuck ring that tightens and holds the insertion part of the tube to the inner core. The tapered outer surface of the in-core has an inclination angle that allows the distal end portion of the resin tube protruding from the chuck ring to expand to a larger diameter than the inner diameter of the chuck ring when contracted. Further, the tapered outer surface portion of the in-core includes a plurality of teeth that can bite into the inner circumferential surface of the tip portion when the resin tube is pulled out. Each tooth is provided in an annular shape surrounding the axis of the inner core. The plurality of teeth are arranged at predetermined intervals in the axial direction of the in-core.

In the resin pipe joint of the same document, when the resin pipes are connected, the in-core expands the end of the resin pipe to a larger diameter than the inner diameter of the chuck ring when the diameter is reduced. Therefore, the distal end portion of the expanded diameter resin tube is caught on the chuck ring and is prevented from slipping out from the chuck ring. Further, the teeth of the in-core bite into the inner circumferential surface of the distal end portion of the expanded diameter resin tube. Therefore, the pulling strength of the resin pipe increases.

JP2010-281411A

In the above pipe joint for resin pipes, when the resin pipes are connected, the teeth of the in-core bite into the inner circumferential surface of the distal end portion of the resin pipe whose diameter has been expanded. Therefore, it is difficult to separate the resin pipe and the inner core when reassembling or removing piping temporarily installed using a resin pipe joint.

In view of these points, an object of the present invention is to provide a pipe joint for a resin pipe in which the resin pipe and the core can be easily separated when the resin pipe is disconnected.

In order to solve the above problems, the present invention provides a pipe joint body including a cylindrical portion having a male thread on the outer circumferential surface, an annular fixing portion fixed to the inner circumferential side of the cylindrical portion, and a lock ring including a lock portion located on one side in the axial direction and expandable and retractable in the radial direction; a nut portion having a female thread that engages with the male thread; A cap nut including a bag portion having a tapered inner peripheral surface that is inclined and contacts the lock portion from the outside in the radial direction, and a cylindrical core body that extends coaxially with the cylindrical portion on the inner peripheral side of the lock ring. a core, the core is immovable in the axial direction, the lock portion is provided with a claw extending in the circumferential direction on an inner surface, and the core body has one side in the axial direction arranged in a first direction. and a protrusion forming part having a spiral protrusion extending from an end in the first direction to the second direction when the other side is a second direction, and the protrusion forming part and the claw are , when connecting resin pipes that face each other in the radial direction, insert the end portion of the resin pipe in the second direction between the lock ring and the core body, and set the cap nut at a predetermined locking position. When the cap nut is screwed into the locking position, the tapered inner circumferential surface pushes the lock portion radially inward and the pawls push against the outer circumferential surface of the resin pipe. It is characterized in that the protrusion bites into the inner circumferential surface of the resin pipe.

In the present invention, when connecting the resin pipe, the end portion of the resin pipe is inserted between the lock ring and the core body, and the cap nut is screwed into the pipe joint body to the lock position. As a result, the tapered inner circumferential surface of the cap nut presses the lock portion radially inward, so that the claws of the lock ring bite into the outer circumferential surface of the resin pipe. In other words, when the cap nut is placed in the lock position, the diameter of the lock portion of the lock ring is reduced by the bag portion, so that the claws of the lock portion bite into the outer circumferential surface of the resin pipe. Further, when the claws bite into the resin tube, the lock portion presses the resin tube against the core body, so that the protrusions provided on the core body bite into the inner circumferential surface of the resin tube. Therefore, when connecting the resin pipes, the tensile strength between the resin pipe and the resin pipe fitting can be ensured. Here, the protrusion that bites into the inner circumferential surface of the resin pipe is spiral, and extends from the end of the core body in the first direction to the second direction. Moreover, the core is immovable in the axial direction. Therefore, when disconnecting the resin pipe, move the cap nut from the locking position in the first direction, and then rotate the resin pipe and the pipe joint for resin pipe relative to each other around the axis to lock the resin pipe. It can be pulled out from between the ring and core. That is, when the cap nut is moved in the first direction, the pressure of the lock part inward in the radial direction by the bag part is loosened, so that the lock part expands in diameter. As a result, the claws of the lock portion are separated from the resin pipe toward the outer circumference, or are easily separated from the resin pipe. Further, when the resin pipe and the resin pipe joint are relatively rotated around the axis, the resin pipe and the core body are guided by the spiral protrusion and move in the direction of separation. Therefore, according to the pipe joint for a resin pipe of the present invention, when disconnecting the resin pipe, the resin pipe and the core can be easily separated. That is, according to the resin pipe joint of the present invention, it is easy to disconnect the resin pipe joint and the resin pipe.

Further, in the present invention, the lock portion includes a plurality of the pawls, the plurality of pawls are arranged at predetermined intervals in the axial direction, and the predetermined spacing is between the protrusions in the axial direction. The distance between the protrusions is greater than or equal to the distance between the protrusions, and the distance between the protrusions is smaller than twice the distance between the protrusions in the axial direction. Therefore, when the lock portion presses the resin tube against the core body, the portion of the protrusion located between the axially adjacent claws tends to bite into the inner circumferential surface of the resin tube.

In the present invention, it is preferable that the protrusion has a sharp outer peripheral end. In this way, when the cap nut is screwed into the pipe joint body to the lock position, it is easy to cause the protrusions of the core to bite into the inner circumferential surface of the resin pipe.

In the present invention, the lock ring is made of resin, and the lock portion includes an annular portion coaxial with the fixing portion, and a plurality of tongue portions protruding from the annular portion in the first direction, The plurality of tongue portions are provided at equal angular intervals around the axis, each tongue portion has a tapered shape toward the first direction, and the claw is provided on each tongue portion, respectively. It can be assumed that In this way, it is easy to expand and contract the lock portion in the radial direction.

In the present invention, the cylindrical portion includes a female thread on an inner circumferential surface and an annular inner protrusion that protrudes inward in the second direction of the female thread, and the fixing portion is screwed onto the female thread. The core includes an annular flange that protrudes outward from the end of the core body in the second direction, and the flange connects the inner protrusion and the lock ring in the axial direction. It can be assumed that it is sandwiched between. In this way, it is easy to fix the lock ring to the cylindrical portion. Further, it is easy to make the core immovable in the axial direction.

In the present invention, the core main body includes a cylindrical portion continuous in the second direction of the protrusion forming portion, and the outer circumferential surface of the cylindrical portion has an outer dimension at an end in the first direction that is an outer dimension of the protrusion. The outer dimensions may be the same as the dimensions, and the tapered surface may have a diameter increasing toward the second direction. In this way, the outer circumferential surface of the cylindrical portion comes into close contact with the inner circumferential surface of the resin pipe, so that the tensile strength of the resin pipe and the resin pipe fitting can be increased.

In the present invention, the locking portion includes an annular packing held in the second direction of the pawl, the packing being located on a radially outer side of a boundary between the protrusion forming portion and the cylindrical portion; When the cap nut is screwed in to the lock position, the packing may be elastically deformed and come into close contact with the outer circumferential surface of the resin pipe. In this way, the packing can seal between the resin pipe and the lock ring. Furthermore, the elastic return force of the packing allows the inner circumferential surface of the resin pipe to be brought into close contact with the boundary between the protrusion forming portion and the cylindrical portion. Thereby, water leakage can be prevented or suppressed from occurring between the resin pipe and the resin pipe fitting.

In the present invention, when the cap nut is screwed to the lock position, the end of the core body in the first direction may protrude further in the first direction than the cap nut. . In this way, the contact area between the inner circumferential surface of the resin pipe and the core body can be increased compared to the case where the end of the core body in the first direction does not protrude beyond the nut in the first direction. . Therefore, the tensile strength of the resin pipe and the resin pipe joint can be increased.

According to the present invention, when the end portion of the resin pipe is inserted between the lock ring and the core body and the cap nut is screwed into the pipe joint body to the lock position, the lock portion of the lock ring is It is pushed to the side and the claws dig into the outer circumferential surface of the resin tube. Furthermore, when the claws of the lock nut bite into the resin tube, the lock portion presses the resin tube against the core, so the protrusion provided at the end portion of the core body in the first direction bites into the inner circumferential surface of the resin tube. Therefore, when connecting the resin pipes, the tensile strength between the resin pipe and the resin pipe fitting can be ensured. Here, the protrusion that bites into the inner circumferential surface of the resin pipe is spiral. Moreover, the core is immovable in the axial direction. Therefore, when disconnecting the resin pipe, move the cap nut from the locking position in the first direction, and then rotate the resin pipe in a predetermined direction around the axis. It can be pulled out from between the core. Therefore, the resin tube and the core can be easily separated.

FIG. 2 is a sectional view of a pipe joint for resin pipes to which the present invention is applied. It is an exploded perspective view of the pipe joint for resin pipes of FIG. It is a sectional view when a resin pipe is connected to a pipe joint for resin pipes.

EMBODIMENT OF THE INVENTION Below, with reference to drawings, the pipe joint for resin pipes which is an embodiment of this invention is demonstrated.

FIG. 1 is a sectional view of a pipe joint for resin pipes to which the present invention is applied. FIG. 2 is an exploded perspective view of the resin pipe joint of FIG. 1. Note that in FIG. 1, only the core is shown in a side view. The resin pipe fitting 1 of this example is used to connect resin pipes when constructing water pipes. The resin pipe is made of polyethylene, for example.

As shown in FIG. 1, the pipe fitting 1 for resin pipes includes a pipe fitting main body 10 including a large diameter cylindrical portion 11 (cylindrical portion), a cap nut 20 screwed into the large diameter cylindrical portion 11, and a large diameter cylindrical portion 11 (cylindrical portion). The lock ring 30 is located inside the portion 11 and the cap nut 20, and the core 50 is located inside the lock ring 30. The resin pipe fitting 1 also includes an O-ring 61 interposed between the lock ring 30 and the pipe fitting body 10, and a packing 62 held by the lock ring 30. In the following description, the direction along the axis L of the large diameter cylindrical portion 11 will be referred to as the axial direction X. Further, one side of the axial direction X is a first direction X1, and the other side is a second direction X2. The first direction X1 is the side on which the cap nut 20 is located with respect to the pipe joint body 10. The second direction X2 is the opposite side, and is the direction in which the cap nut 20 is screwed into the pipe joint body 10.

The pipe joint body 10 is cylindrical. The pipe joint body 10 includes a large-diameter cylindrical portion 11 , an annular wall portion 12 extending inward from the end of the large-diameter cylindrical portion 11 in the second direction A small diameter cylindrical portion 13 extending in the second direction X2 is provided. The large-diameter cylindrical portion 11 includes a male thread 11a on its outer peripheral surface. Further, the large diameter cylindrical portion 11 includes an annular outer protrusion 15 that protrudes toward the outer circumference in the second direction X2 of the male thread 11a. Furthermore, the large diameter cylindrical portion 11 is provided with a female thread 11b on the inner circumferential surface. The large-diameter cylindrical portion 11 includes an annular inner protrusion 16 that protrudes toward the inner circumference in the second direction X2 of the female thread 11b. The inner protrusion 16 is located further in the first direction X1 than the outer protrusion 15. The small diameter cylindrical portion 13 is located in the second direction X2 of the large diameter cylindrical portion 11. The small diameter cylindrical portion 13 is coaxial with the large diameter cylindrical portion 11 . The small diameter cylindrical portion 13 has a smaller external dimension than the large diameter cylindrical portion 11. A male thread 13a for connecting the resin pipe fitting 1 to another piping member is provided on the outer peripheral surface of the small diameter cylindrical portion 13. Note that the male thread 13a is an example of a connection structure for connecting the resin pipe fitting 1 to another piping member. Therefore, the outer peripheral surface of the small diameter cylindrical portion 13 may not be provided with the male thread 13a.

The lock ring 30 is made of resin. The lock ring 30 includes an annular fixing part 31 located on the inner peripheral side of the large diameter cylindrical part 11, and a locking part 32 located in the first direction X1 of the large diameter cylindrical part 11 and expandable and contractible in the radial direction.

The fixing part 31 includes a male thread 31a that is screwed into the female thread 11b of the large diameter cylindrical part 11. Furthermore, the fixing portion 31 includes an annular thick portion 33 that protrudes toward the inner circumferential side at an end in the second direction X2. The thick portion 33 includes an annular end surface 33a facing the first direction X1 and an inner peripheral wall surface 33b facing the inner peripheral side. The thick portion 33 is provided with an annular protrusion 34 that protrudes toward the inner circumference. Furthermore, the fixing part 31 includes a chamfered part 35 recessed in the first direction X1 and inward on the outer peripheral side of the end in the second direction X2.

The annular protrusion 34 protrudes inward from the end of the thick portion 33 in the first direction X1. The end surface of the annular protrusion 34 in the first direction X1 is continuous with the annular end surface 33a of the thick portion 33 without a step. Further, the annular protrusion 34 is provided at a position spaced apart from the end of the thick portion 33 in the second direction X2 in the first direction X1. Therefore, the inner peripheral wall surface 33b of the thick portion 33 extends toward the second direction X2 from the outer peripheral end of the end surface of the annular protrusion 34 in the second direction X2. Here, on the end surface of the annular protrusion 34 in the first direction X1, engagement recesses 34a recessed in the second direction X2 are provided at four locations in the circumferential direction. The four engaging recesses 34a are formed at equal angular intervals.

The lock ring 30 is fixed to the pipe joint body 10 by screwing together the male thread 31a of the fixing part 31 and the female thread 11b of the large diameter cylindrical part 11. When fixing the lock ring 30 to the pipe joint body 10, first, a rod-shaped jig (not shown) is provided at the end portion in the second direction X2 with four engagement protrusions that can engage with the engagement recess 34a. prepare. Next, the jig is inserted inside the lock ring 30, and the engagement protrusion of the jig is engaged with the engagement recess 34a. Thereafter, the lock ring 30 is rotated by rotating the jig relative to the pipe joint body 10, and the male thread 31a of the lock ring 30 is tightened to the female thread 11b of the pipe joint body 10. Thereby, the lock ring 30 and the pipe joint body 10 are firmly fixed.

Note that when the lock ring 30 is fixed to the pipe joint body 10, an O-ring 61 is arranged on the chamfered portion 35. When the lock ring 30 is fixed to the pipe fitting main body 10, the O-ring 61 will be in a compressed state between the lock ring 30 and the pipe fitting main body 10. When the lock ring 30 is fixed to the pipe joint body 10, the end surface of the fixing portion 31 in the second direction X2 faces the inner protrusion 16 with a narrow gap therebetween.

Further, the lock ring 30 is fixed to the pipe joint body 10 with the core 50 disposed on the inner peripheral side of the lock ring 30. When the lock ring 30 is fixed to the pipe joint body 10, the annular protrusion 34 contacts the core body 51 of the core 50 from the outer peripheral side, as will be described in detail later. Further, the flange 52 of the core 50 is sandwiched between the inner protrusion 16 of the pipe joint body 10 and the annular protrusion 34 of the lock ring 30.

Next, the lock portion 32 includes an annular portion 36 coaxial with the fixing portion 31 and a plurality of tongue portions 37 protruding from the annular portion 36 in the first direction X1. In this example, six tongue portions 37 protrude from the annular portion 36. The plurality of tongue portions 37 are provided at equal angular intervals around the axis L. When each tongue piece portion 37 is viewed from the axial direction X, it has a circular arc shape. Further, each tongue portion 37 has a shape tapered toward the first direction X1.

Further, the lock portion 32 includes a plurality of claws 38 extending in the circumferential direction on the inner surface. The plurality of claws 38 are arranged at predetermined intervals in the axial direction X. A plurality of claws 38 are provided on each tongue portion 37, respectively. That is, each tongue portion 37 has a plurality of claws 38 arranged on its inner peripheral surface at predetermined intervals M in the axial direction X, and the inner peripheral side end of each claw 38 is sharp.

Further, the lock portion 32 includes an annular recess 39 recessed toward the outer circumferential side in the second direction X2 of the claw 38. The annular recess 39 is provided from an end portion of the annular portion 36 in the first direction X1 to an end portion of each tongue piece portion 37 in the second direction X2. An annular packing 62 is inserted into the annular recess 39 . The packing 62 is made of an elastic member such as rubber. In the packing 62, the outer peripheral surface facing outward in the radial direction includes a tapered surface 62a that slopes toward the outer peripheral side toward the second direction X2.

The cap nut 20 includes a nut portion 21 having a female thread 21a that is screwed into the male thread 11a of the large diameter cylindrical portion 11, and a bag portion 22 located in the first direction X1 of the nut portion 21. The bag portion 22 has a tapered inner peripheral surface 22a that is inclined toward the inner peripheral side in the first direction X1 and contacts the lock portion 32 from the outside in the radial direction.

The core 50 includes a cylindrical core body 51 that extends coaxially with the large diameter cylindrical portion 11 on the inner circumferential side of the lock ring 30, and an annular flange 52 that protrudes toward the outer circumferential side from the end of the core body 51 in the second direction X2. and.

The core body 51 includes a protrusion forming part 54 having a single spiral protrusion 53 extending from an end in the first direction X1 in the second direction X2, and a cylindrical part continuous in the second direction X2 of the protrusion forming part 54. 55. The protrusion 53 has a chevron-shaped shape when cut along a plane along the axis L. The protrusion 53 has a sharp outer peripheral end. The protrusion forming portion 54 and the plurality of claws 38 of the lock ring 30 face each other in the radial direction. The interval N between the protrusions 53 in the axial direction X is less than or equal to a predetermined interval M at which adjacent pawls 38 are spaced apart from each other in the axial direction X. In other words, the predetermined interval M between the pawls 38 located next to each other in the axial direction X is greater than or equal to the interval N between the protrusions 53 in the axial direction smaller than

The outer peripheral surface 55a of the cylindrical portion 55 is a tapered surface that expands in diameter toward the second direction X2. The outer dimensions of the end of the outer circumferential surface 55a of the cylindrical portion 55 in the first direction X1 are the same as the outer dimensions of the protrusion 53. Here, the boundary between the protrusion forming portion 54 and the cylindrical portion 55 faces the packing 62 in the radial direction. In other words, the packing 62 is located on the radially outer side of the protrusion forming portion 54 and the cylindrical portion 55. Further, the end portion of the outer circumferential surface 55a of the cylindrical portion 55 in the second direction X2 is in contact with the annular protrusion 34.

The flange 52 is sandwiched between the inner protrusion 16 of the pipe joint body 10 and the annular protrusion 34 of the lock ring 30 in the axial direction X. More specifically, the end surface of the flange 52 in the first direction X1 is in contact with the annular protrusion 34 of the lock ring 30. The end surface of the flange 52 in the second direction X2 is in contact with the inner protrusion 16 of the pipe joint body 10. Further, the outer peripheral end surface of the flange 52 is in contact with the inner peripheral wall surface 33b of the thick portion 33 of the lock ring 30. Thereby, the core 50 is supported by the large diameter cylindrical portion 11 and the lock ring 30 in a state where it is immovable in the axial direction X and in a state where it is immovable in the radial direction.

(Connection between resin pipe and resin pipe fitting)
FIG. 3 is a cross-sectional view of a resin pipe connected to the resin pipe fitting 1. In FIG. 3, only the core 50 is shown in a side view. When connecting the resin pipe 100, the resin pipe fitting 1 is in the state shown in FIG. 1. That is, although the cap nut 20 is screwed into the pipe joint body 10, it is arranged in the first direction X1 with respect to the lock position where it is screwed into the pipe joint body 10 the most.

In this state, the end portion of the resin tube 100 in the second direction X2 is inserted between the lock ring 30 and the core body 51. Then, the end surface of the resin pipe 100 in the second direction X2 is brought into contact with the annular end surface 33a of the thick portion 33 of the lock ring 30 and the annular protrusion 34.

Here, in this example, the outer diameter dimension of the protrusion forming portion 54 (outer dimension of the protrusion 53) is a dimension that can be inserted into the resin pipe 100, and is substantially the same as the inner diameter dimension of the resin pipe 100. It is. Further, the outer circumferential surface 55a of the cylindrical portion 55 that is continuous in the second direction X2 of the protrusion forming portion 54 is a tapered surface that increases in diameter toward the second direction It is the same as the outer diameter dimension of the protrusion forming portion 54 (outer dimension of the protrusion 53). Therefore, by pushing the resin tube 100 in the second direction X2, the end portion of the resin tube 100 in the second direction X2 can be inserted between the lock ring 30 and the core body 51. Furthermore, by pushing the resin tube 100 in the second direction X2, the end surface of the resin tube 100 in the second direction X2 can be brought into contact with the annular end surface 33a of the thick portion 33 of the lock ring 30 and the annular protrusion 34. can. Further, the outer circumferential surface 55a of the cylindrical portion 55 of the core 50 is a tapered surface whose diameter increases toward the second direction X2. Therefore, when the end portion of the resin tube 100 is brought into contact with the annular end surface 33a of the thick portion 33 of the lock ring 30 and the annular protrusion 34, the outer circumferential surface 55a of the cylindrical portion 55 and the inner circumferential surface 100b of the resin tube 100 and can be brought into close contact with each other. Therefore, the tensile strength of the resin pipe 100 and the resin pipe fitting 1 can be increased.

Next, the cap nut 20 is screwed into the pipe joint body 10 to the lock position 20A. When the cap nut 20 is screwed to the lock position 20A, the tapered inner circumferential surface 22a pushes the lock portion 32 radially inward. As a result, the diameter of the lock portion 32 is reduced by the bag portion 22 of the cap nut 20, so that the plurality of claws 38 of the lock portion 32 bite into the outer circumferential surface 100a of the resin pipe 100. Furthermore, when the claw 38 of the lock nut bites into the resin tube 100, the lock portion 32 presses the resin tube 100 against the core body 51, so that the protrusion 53 provided on the core body 51 is pressed against the inner circumferential surface 100b of the resin tube 100. Dig in. Therefore, the tensile strength between the resin pipe 100 and the resin pipe fitting 1 is ensured.

Here, the interval N between the protrusions 53 in the axial direction X is equal to or less than a predetermined interval M at which claws 38 located next to each other in the axial direction X are spaced apart from each other. In other words, the predetermined distance M between adjacent pawls 38 in the axial direction X is equal to or greater than the distance N between the protrusions 53 in the axial direction It's also small. Therefore, when the lock portion 32 presses the resin tube 100 against the core body 51, the portion of the protrusion 53 located between the adjacent claws 38 in the axial direction X tends to bite into the inner circumferential surface of the resin tube.

Further, the lock ring 30 is made of resin. Further, the locking portion 32 includes an annular portion 36 coaxial with the fixing portion 31 and a plurality of tongue portions 37 protruding from the annular portion 36 in the first direction X1. Further, the plurality of tongue portions 37 are provided at equal angular intervals around the axis L. Furthermore, each tongue piece portion 37 has a tapered shape toward the first direction X1. Therefore, it is easy to expand and contract the lock portion 32 in the radial direction.

Furthermore, the protrusion 53 has a sharp outer peripheral end. Therefore, when the cap nut 20 is screwed into the pipe joint body 10 to the lock position 20A, the protrusion 53 of the core 50 easily bites into the inner circumferential surface 100b of the resin pipe 100.

Furthermore, when the cap nut 20 is screwed in to the lock position 20A, the packing 62 is elastically deformed and comes into close contact with the outer circumferential surface 100a of the resin pipe 100. Therefore, the packing 62 can seal between the resin pipe 100 and the lock ring 30. Furthermore, the packing 62 is located on the radially outer side of the protrusion forming portion 54 and the cylindrical portion 55. Therefore, the elastic return force of the packing 62 allows the inner circumferential surface 100b of the resin tube 100 to be brought into close contact with the boundary between the protrusion forming portion 54 and the cylindrical portion 55. Thereby, water leakage between the resin pipe 100 and the resin pipe fitting 1 can be prevented or suppressed.

Furthermore, when the cap nut 20 is screwed in to the lock position 20A, the end 51a of the core body 51 in the first direction X1 protrudes further than the cap nut 20 in the first direction X1. Therefore, compared to the case where the end 51a of the core body 51 in the first direction X1 does not protrude beyond the cap nut 20 in the first direction can be increased. Therefore, the tensile strength of the resin pipe 100 and the resin pipe fitting 1 can be increased.

(Release of connection between resin pipe and resin pipe fitting)
When disconnecting the resin pipe 100 when reassembling or removing piping temporarily installed using the resin pipe fitting 1, first move the cap nut 20 from the locking position 20A in the first direction X1. . Here, if the cap nut 20 is moved in the first direction X1, the pressure of the lock part 32 inward in the radial direction by the bag part 22 is loosened, so that the lock part 32 expands in diameter. As a result, the claws 38 of the lock portion 32 are separated from the resin tube 100 toward the outer circumference. Alternatively, the claws 38 of the lock portion 32 are easily separated from the resin pipe 100 toward the outer circumference.

Next, as shown by the arrow in FIG. 3, the resin pipe fitting 1 is rotated in a predetermined direction R around the axis L. Here, the protrusion 53 of the core 50 that bites into the inner circumferential surface 100b of the resin pipe 100 is spiral, and extends from the end 51a of the core body 51 in the first direction X1 to the second direction X2. Further, the core 50 is immovable in the axial direction X. Therefore, when the resin pipe fitting 1 is rotated in a predetermined direction R around the axis L, the resin pipe fitting 1 is guided by the spiral protrusion 53 and moves in the second direction X2. Therefore, according to the resin pipe fitting 1 of this example, when disconnecting the resin pipe 100, the resin pipe 100 and the core 50 can be easily separated. That is, according to the resin pipe fitting 1 of this example, it is easy to disconnect the resin pipe 100 and the resin pipe fitting 1.

Note that the fixing portion 31 of the lock ring 30 only needs to be fixed to the inner peripheral side of the large diameter cylindrical portion 11, and the fixing method for fixing the lock ring 30 to the large diameter cylindrical portion 11 is to use the external thread 11a of the lock ring 30. It is not limited to the screw engagement between the screw and the female thread 11b of the large-diameter cylindrical portion 11. Moreover, the core 50 only needs to be held on the inner circumferential side of the cylindrical portion of the large-diameter cylindrical portion 11 in a state where it cannot move in the axial direction X. Therefore, the core 50 may be supported by the pipe joint body 10 in a state where it cannot move in the axial direction X. Alternatively, it may be supported by the lock ring 30 in a state where it cannot move in the axial direction X. Furthermore, the core 50 may be provided integrally with the pipe joint body 10.

In addition, when the cap nut 20 is screwed in to the lock position 20A, the core body 51
The tip 51a may be located inside the cap nut 20 in the radial direction.

DESCRIPTION OF SYMBOLS 1... Pipe joint for resin pipes, 10... Pipe coupling body, 11... Large diameter cylindrical part (cylindrical part), 11a... Male thread, 11b... Female thread, 12... Annular wall part, 13... Small diameter cylindrical part, 15... Outer protrusion, 16...Inner protrusion, 20...Cap nut, 20A...Lock position, 21...Nut part, 21a...Female thread, 22...Bag part, 22a...Tapered inner peripheral surface, 30...Lock ring, 31...Fixing part, 32...Lock Part, 33... Thick part, 33a... Annular end surface, 33b... Inner circumferential wall surface, 34... Annular protrusion, 34a... Engagement recess, 35... Chamfered part, 36... Annular part, 37... Tongue piece part, 38... Claw , 39... Annular recess, 50... Core, 51... Core main body, 52... Flange, 53... Projection, 54... Projection forming part, 55... Cylindrical part, 55a... Outer peripheral surface of cylindrical part, 61... O-ring, 62 ...Packing, 100...Resin pipe, 100a...Outer circumferential surface of resin pipe, 100b...Inner circumferential surface of resin pipe, L...Axis line, M...Interval between pawls in the axial direction, N...Interval between spiral protrusions in the axial direction, X...Axis direction, X1...First direction, X2...Second direction

Claims (7)

a pipe fitting body including a cylindrical portion having a male thread on its outer circumferential surface;
a lock ring comprising an annular fixing part fixed to an inner circumferential side of the cylindrical part, and a locking part located on one side of the axial direction of the cylindrical part and capable of expanding and contracting in a radial direction;
a nut portion having a female thread that is screwed into the male thread; and a bag portion having a tapered inner peripheral surface that is inclined inward toward one side in the axial direction and contacts the lock portion from the outside in the radial direction. A cap nut provided,
a core including a cylindrical core body extending coaxially with the cylindrical portion on the inner peripheral side of the lock ring;
has
The core is immovable in the axial direction,
The lock portion includes a plurality of claws extending in the circumferential direction on the inner surface,
The core body has a protrusion forming portion having a helical protrusion extending from an end in the first direction in the second direction when one side in the axial direction is a first direction and the other side is a second direction. Equipped with
The protrusion forming portion and the claw face each other in a radial direction,
The plurality of claws are arranged at predetermined intervals in the axial direction,
The predetermined interval is greater than or equal to the interval between the protrusions in the axial direction and smaller than twice the interval between the protrusions in the axial direction,
When connecting a resin pipe, the end portion of the resin pipe in the second direction is inserted between the lock ring and the core body, and the cap nut is twisted onto the pipe joint body to a predetermined locking position. When the cap nut is screwed into the locking position, the tapered inner circumferential surface pushes the lock portion radially inward, the pawls bite into the outer circumferential surface of the resin pipe, and the protrusions A pipe joint for a resin pipe, wherein the pipe fitting bites into the inner circumferential surface of the resin pipe. The pipe joint for a resin pipe according to claim 1, wherein the protrusion has a sharp outer peripheral end. The lock ring is made of resin,
The locking portion includes an annular portion coaxial with the fixing portion, and a plurality of tongue portions protruding from the annular portion in the first direction,
The plurality of tongue pieces are provided at equal angular intervals around the axis,
Each tongue portion has a tapered shape toward the first direction,
The pipe joint for a resin pipe according to claim 1 or 2 , wherein the claw is provided on each tongue piece. The cylindrical portion includes a female thread on an inner circumferential surface, and an annular inner protrusion that protrudes inward in the second direction of the female thread,
The fixing part includes a male thread that is screwed into the female thread,
The core includes an annular flange that protrudes toward the outer circumferential side from the end of the core body in the second direction,
The pipe joint for a resin pipe according to any one of claims 1 to 3 , wherein the flange is sandwiched between the inner protrusion and the lock ring in the axial direction. The core body includes a cylindrical portion that is continuous in the second direction of the protrusion forming portion,
The outer circumferential surface of the cylindrical portion is a tapered surface whose outer dimension at the end in the first direction is the same as the outer dimension of the protrusion, and whose diameter increases toward the second direction. The pipe joint for a resin pipe according to any one of claims 1 to 4 . an annular packing held in the second direction of the claw in the locking part;
The packing is located on the outer side in the radial direction of the boundary between the protrusion forming part and the cylindrical part,
6. The pipe joint for a resin pipe according to claim 5 , wherein when the cap nut is screwed to the lock position, the packing is elastically deformed and comes into close contact with the outer peripheral surface of the resin pipe. Claims 1 to 6, wherein when the cap nut is screwed to the lock position, the end of the core body in the first direction protrudes beyond the cap nut in the first direction. The pipe fitting for resin pipes according to any one of the above.

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