JP5318404B2 - Pipe fitting - Google Patents

Description

  The present invention relates to a pipe joint used when connecting a water pipe or other pipe body having at least an outer peripheral portion made of resin to another pipe body or equipment.

  Generally, this type of pipe joint includes a joint body having a passage hole formed therein and a locking ring provided at one end of the passage hole as described in Patent Document 1 below. ing. The locking ring has an annular base portion that is substantially immovable in the passage hole, and a large number of biting teeth that protrude obliquely inward from the inner peripheral portion of the base portion.

  When the resin tube (tubular body) is inserted into the passage hole from the opening at one end thereof, the resin tube penetrates the locking ring while elastically deforming the biting teeth of the locking ring. When the resin tube is inserted to a predetermined position and then pulled back, the biting teeth bite into the outer peripheral surface of the resin tube. As a result, the resin pipe is connected to the joint body in a retaining state.

Japanese Patent No. 2945653

FIG. 10 shows the resin pipe T connected by the conventional pipe joint. On the outer peripheral surface of the resin tube T, a biting trace Tx when the biting tooth bites is formed. The mutually adjacent ends of the two biting traces Tx and Tx adjacent in the circumferential direction of the resin tube T are located at the same position in the longitudinal direction of the resin tube T. Moreover, the interval W between the two biting traces Tx and Tx is small. For this reason, when the resin pipe connected to the joint body is pulled strongly in the extraction direction, cracks extend in the circumferential direction from both end portions of the biting trace Tx, and the two biting traces Tx and Tx are continuous in the circumferential direction. As a result, the resin tube T may be broken from the portion where the bite mark Tx is formed.
If the distance between the two biting traces Tx and Tx is increased, the resin tube T can be prevented from being broken. However, if this is done, the width of the biting tooth is reduced or the biting is reduced. The number of teeth will decrease. As a result, another problem that the fixing strength with respect to the resin tube T is reduced occurs.

In order to solve the above-described problem, the present invention provides a joint body having a passage hole penetrating through the inside thereof and at least an outer peripheral portion made of resin inserted into the passage hole from one end opening thereof. A locking ring provided at one end of the passage hole, and the locking ring is provided in a state in which the locking hole is prevented from moving beyond a predetermined range in the longitudinal direction of the passage hole. An annular base portion and an inner peripheral portion of the base portion, and a plurality of biting teeth protruding from the base portion in a state of being inclined inward in the radial direction toward the front in the insertion direction of the tube body. When the tubular body is inserted into the locking ring from one end opening of the passage hole and then pulled back to the outside of the passage hole, the biting teeth bite into the outer peripheral surface of the tubular body, thereby the tubular body Prevents the fitting body from coming off In the pipe joint connected in a state, when the two biting teeth adjacent in the circumferential direction of the locking ring are the first and second biting teeth, respectively, the first and second biting teeth are in the locking ring. The first biting teeth are alternately arranged in the circumferential direction, and end portions adjacent to each other in the circumferential direction of the first and second biting teeth respectively bite into the tube body at different positions in the longitudinal direction. The amount of protrusion from the base of the one end and the other end is the amount of protrusion from the base of each end of the second biting tooth adjacent to the one end and the other end of the first biting tooth, respectively. Each is set large,
The first and second biting teeth are formed such that the center portion in the circumferential direction of the locking ring protrudes larger than both end portions, and the protruding amount of the center portion of the first biting tooth is the second biting tooth. It is set larger than the protruding amount of the central portion of the tooth, and the diameter of the circle in contact with the central portion in the circumferential direction of each first biting tooth is set to be smaller than the outer diameter of the resin tube, The diameter of the circle in contact with the center of the resin tube is set to be larger than the outer diameter of the resin tube, and when the resin tube into which the first bite is bitten is pulled back, the base is elastically deformed, whereby the second bite teeth are It is characterized by biting into the resin tube.
In this case, it is desirable that each tip portion in the protruding direction of the first and second biting teeth is formed by a convex curved surface that bulges inward in the radial direction of the locking ring.
It is desirable that the inclination angle of the first biting tooth with respect to the axis of the base is set to be smaller than the inclination angle of the second biting tooth with respect to the axis of the base.

  According to this invention having the above-described characteristic configuration, the first and second biting marks are formed on the outer peripheral surface of the tubular body by the first and second biting teeth adjacent in the circumferential direction. In this case, since the projecting amounts of the first and second biting teeth from the ends of the adjacent end portions are different from each other, the ends adjacent to each other in the circumferential direction of the first and second biting traces are They are located at different positions without being located at the same position in the longitudinal direction of the tubular body. Therefore, the distance between the adjacent end portions of the first and second bite marks becomes longer as they are separated from each other in the longitudinal direction of the tubular body, and the breaking strength of the portion where the bite mark is formed is increased accordingly. Can be high. Therefore, it can prevent that a tubular body fractures | ruptures from the part of the biting trace.

The best mode for carrying out the present invention will be described below with reference to the drawings.
1 to 8 show a first embodiment of the present invention. In this embodiment, the present invention is applied to a pipe joint 1 for water supply. The present invention can also be applied to pipe joints other than water pipe joints, for example, gas pipe joints.

  The pipe joint 1 includes a joint body 2. A passage hole 2 a that penetrates from one end surface (the right end surface in FIG. 1) to the other end surface is formed in the joint body 2. The passage hole 2a is inserted with a resin pipe (pipe) T for water supply through an opening at one end thereof and connected to the joint body 2 as described later. A tapered male screw portion 2 b is formed on the outer peripheral surface of the other end portion of the joint body 2. To this taper male screw portion 2b, another pipe for water supply or a water supply device (both not shown) is screwed and fixed. Thereby, the resin pipe T is connected to another pipe body or equipment via the pipe joint 1. In addition, instead of the resin tube T made entirely of resin, a tube body in which the outer periphery of the aluminum tube is covered with a resin layer may be connected.

  On the inner peripheral surface of the passage hole 2a, an inner cylindrical portion 2c extending from an intermediate portion in the longitudinal direction to one end surface of the joint body 2 is formed. Thus, approximately half of one end side of the passage hole 2a is divided into an annular outer hole portion 2d and an inner hole portion 2e coaxial with the outer hole portion 2d. Half has a double cylinder structure. The inner diameter of the outer hole portion 2d is substantially the same as or slightly larger than the outer diameter of the resin tube T, and the outer diameter of the inner tube portion 2c is substantially the same as or slightly smaller than the inner diameter of the resin tube T. . Therefore, the resin tube T can be inserted into the outer hole portion 2d from the opening at one end thereof. When the resin tube T is inserted into the outer hole portion 2d, the inside of the resin tube T communicates with the inner hole portion 2e. A seal member 3 such as an O-ring is provided on the outer peripheral surface of the inner cylinder portion 2c. The seal member 3 seals between the inner peripheral surface of the resin tube T and the outer peripheral surface of the inner cylindrical portion 2c (see FIGS. 6 to 8).

  A short cylindrical guide member 4 is inserted into the end of the outer hole 2d on the opening side. The guide member 4 is slidably fitted to the outer peripheral surface of the inner cylinder portion 2c. The guide member 4 is for preventing the tip surface of the resin tube T from damaging the seal member 3 when the resin tube T is inserted into the outer hole portion 2d. It is arrange | positioned at the opening part side. Therefore, when the resin tube T is inserted into the outer hole portion 2d, the resin tube T abuts against the guide member 4 before it abuts against the seal member 3. When the resin tube T is further inserted into the outer hole portion 2d, the guide member 4 is moved to the bottom side of the outer hole portion 2d. Then, the taper portion 4 a provided on the inner peripheral surface of the guide member 4 reduces the diameter of the seal member 3. Then, at the same time as the guide member 4 passes, the resin tube T passes over the seal member 3 having a reduced diameter. Therefore, the tip surface of the resin tube T does not hit the seal member 3, and the seal member 3 is not damaged by the tip surface of the resin tube T. An annular projecting portion 2f for preventing the guide member 4 from coming out of the outer hole portion 2d to the outside is formed at the opening side end portion of the inner peripheral surface of the outer hole portion 2d.

  An annular recess 2g is formed on the inner peripheral surface of the outer hole 2d facing the inner end of the guide member 4 (the left end in FIG. 1). A locking ring 5 is attached to the annular recess 2g. The locking ring 5 is made of a thin metal plate and has a base portion 51 and first and second biting teeth (biting teeth) 52 and 53.

  The base 51 has an annular shape, and is disposed in the annular recess 2g in a state in which the axis thereof coincides with the axis of the passage hole 2a. The base 51 is movable in the longitudinal direction of the outer hole 2d (passage hole 2a) in the annular recess 2g, but the movable distance is very small, and the base 51 does not come out of the outer hole 2d. Further, it does not move beyond the seal member 3 to the bottom side of the outer hole portion 2d. The base 51 may be provided in the outer hole 2d so as not to move in the longitudinal direction.

  The first and second biting teeth 52 and 53 are formed integrally with the base 51 on the inner periphery of the base 51, and are alternately arranged in the circumferential direction of the base 51 with a narrow slit 54 therebetween. ing. The first and second biting teeth 52 and 53 are inclined so as to go inward in the radial direction of the base 51 toward the front in the insertion direction of the resin tube T (the direction from one end side to the other end side of the passage hole 2a). It has been. The inclination angles of the first and second biting teeth 52 and 53 with respect to the axis of the passage hole 2a are set to the same angle.

  The front end surface of the first biting tooth 52 in the protruding direction is formed by an arc surface that is convex toward the inside of the base 51. The center of curvature of the arc surface is disposed on the radial line of the base 51 passing through the center of the first biting tooth 52 in the width direction (the circumferential direction of the base 51). Therefore, the protruding amount of the first biting tooth 52 is the largest at the center in the width direction and the smallest at both ends. The diameter of the circle in contact with the center of each first biting tooth 52 is smaller than the outer diameter of the resin tube T. Therefore, when the resin tube T is inserted into the locking ring 5, the central portion of the first biting tooth 52 is pushed to the bottom side of the outer hole portion 2d by the resin tube T, and the axis of the base portion 51 (the axis of the passage hole 2a). The first biting tooth 52 is elastically deformed so that the inclination angle of the first biting tooth 52 becomes small. As a result, the diameter of the circle in contact with the center of the first biting tooth 52 becomes large, and the resin tube T can be inserted in a state where the locking ring 5 is in sliding contact with the center portion of the first biting tooth 52. In this embodiment, the outer diameter of the rear end portion of the guide member 4 in the insertion direction of the resin tube T is set to be the same as the outer diameter of the resin tube T. The one biting tooth 52 is elastically deformed.

  The distal end surface in the protruding direction of the second biting tooth 53 is also formed by an arc surface convex toward the inside of the base 51, and the center of curvature of the arc surface passes through the center in the width direction of the second biting tooth 53. It is arranged on the radial line of the base 51. Therefore, the protruding amount of the second biting tooth 53 is also the largest at the center in the width direction and the smallest at both ends. The diameter of the circle in contact with the center in the width direction of each second biting tooth 53 is slightly larger than the outer diameter of the resin tube T within a range that satisfies the conditions described later. The diameter of the circle in contact with the center in the width direction of each second biting tooth 53 may be equal to or smaller than the outer diameter of the resin tube T.

  As described above, the diameter of the circle in contact with the center of each first bite tooth 52 is smaller than the outer diameter of the resin tube T, whereas the diameter of the circle in contact with the center of each second bite tooth 53 is resin. The diameter is slightly larger than the outer diameter of the tube T. Moreover, since the inclination angles of the first and second biting teeth 52 and 53 are set to be the same, the amount of protrusion of the first biting tooth 52 is half the diameter of both circles. It is larger than the protruding amount. In addition, the arc surface constituting the tip surface of the first biting tooth 52 and the arc surface constituting the tip surface of the second biting tooth 53 have the same radius of curvature. Therefore, the amount of protrusion at both ends of the first biting tooth 52 is also larger than the amount of protrusion at both ends of the second biting tooth 53 by half the diameter of both circles.

  When the resin pipe T is connected to another pipe body or equipment using the pipe joint 1 having the above-described configuration, the resin pipe T is inserted into the outer hole portion 2d and coupled to the joint body 2 while the other pipe body. Alternatively, the device is screwed and fixed to the tapered male screw portion 2b. Thereby, the resin pipe T can be connected to another pipe body or equipment via the pipe joint 1. Either the connection of the resin pipe T to the joint body 2 or the screwing and fixing of another pipe body or device to the joint body 2 may be performed first.

  The connection of the resin pipe T to the joint body 2 can be performed as follows. That is, the resin tube T is inserted into the outer hole portion 2d from the opening at one end thereof. Then, as shown in FIG. 5, the distal end surface of the resin tube T abuts against the guide member 4. Therefore, after that, the guide member 4 moves together with the resin tube T. When the guide member 4 moves to the bottom side of the outer hole portion 2d, the outer peripheral surface of the guide member 4 abuts against the first biting tooth 52 to be elastically deformed, and the diameter of the circle in contact with the central portion of the first biting tooth 52 is increased. To. As a result, the resin tube T can be inserted in a state where the locking ring 5 is in sliding contact with the first biting tooth 52. The guide member 4 reduces the diameter of the seal member 3. Accordingly, the resin tube T passes over the seal member 3 without hitting the seal member 3 (see FIGS. 6 and 7).

  When the resin tube T is inserted to a predetermined position of the outer hole portion 2d, as shown in FIG. 6, for example, the resin tube T is pulled back when the guide member 4 is inserted until it hits the bottom of the outer hole portion 2d. Then, as shown in FIG. 7, the first biting tooth 52 that press-contacts the outer peripheral surface of the resin tube T bites into the outer peripheral surface of the resin tube T in accordance with the pulling back. The first biting teeth 52 are elastically deformed so that the inclination angle increases as the amount of biting into the resin tube T increases, that is, the diameter of the circle in contact with the central portion of the first biting teeth 52 decreases. . Then, the base 51 is elastically deformed according to the elastic deformation of the first biting tooth 52. As a result, the inclination angle of the second biting tooth 53 is increased, and the diameter of the circle in contact with the center of the second biting tooth 53 is decreased. Then, when the resin tube T is pulled back by a predetermined distance, the central portion of the second biting tooth 53 that has been separated from the outer peripheral surface of the resin tube T comes into press contact with the outer peripheral surface of the resin tube T. As a result, as shown in FIG. 8, the second biting teeth 53 also bite into the outer peripheral surface of the resin tube T. When the resin tube T is pulled back by a predetermined distance, one end to the other end in the width direction of each of the first and second biting teeth 52 and 53 bite into the resin tube T and cannot be pulled back any further. Thereby, the resin pipe T is connected to the joint body 2 so as not to be extracted from the outer hole portion 2d to the outside.

  As is clear from the above contents, when the diameter of the circle in contact with the center of each second biting tooth 53 is larger than the outer diameter of the resin tube T, the second biting tooth 52 is bitten by the first biting tooth 52. It is essential to satisfy the condition that the teeth 53 can also bite into the resin tube T.

  FIG. 9 shows the resin pipe T in which the first and second biting marks Ta and Tb are formed on the outer peripheral surface. The first biting trace Ta is a biting trace of the first biting tooth 52, and the second biting trace Tb is a biting trace of the second biting tooth. As is clear from this figure, the first and second biting marks Ta and Tb are formed at different positions in the longitudinal direction of the resin tube T. In particular, in this embodiment, the first biting trace Ta is located forward (leftward in FIG. 9) in the insertion direction of the resin tube T from the second biting trace Tb, and both end portions of the first biting trace Ta. However, it is located ahead from the both ends of 2nd bite mark Tb. Therefore, even if the circumferential interval W between the adjacent end portions of the first biting trace Ta and the second biting trace Tb is the same as the interval of the biting trace by the conventional locking ring, the first biting trace Ta And the distance between the adjacent end portions of the second biting trace Tb is longer by the distance between both end portions of both biting traces Ta and Tb in the longitudinal direction of the resin tube T, and the first and The breaking strength of the portion where the double bite marks Ta and Tb are formed is increased. Therefore, it is possible to prevent the resin tube T from being broken from the first and second biting marks Ta and Tb.

Next, a modified example of the locking ring 5 used in the pipe joint 1 according to the present invention and a reference example of the locking ring used in a pipe joint unrelated to the present invention will be described. In addition, about the following modification and reference examples, only the structure different from the said locking ring 5 is demonstrated.

  11 and 12 show a locking ring 5A that is a first modification of the locking ring 5. FIG. In the locking ring 5 </ b> A, a buffer hole 55 is formed in the base 51. The buffer holes 55 are formed in the same number as the slits 54, and are arranged so that the side portions located on the radially inner side of the base portion 51 communicate with the slits 53. When such a buffer hole 55 is formed, the elastic deformation of the base 51 accompanying the elastic deformation of the first and second biting teeth 52 and 53 can be reduced. As a result, when the first biting tooth 52 bites into the resin tube T, the diameter of the circle in contact with the second biting tooth 53 is not so small. Therefore, when this locking ring 5 </ b> A is used, the diameter of the circle in contact with each center of the second biting tooth 53 is made equal to or smaller than the outer diameter of the resin tube T.

13 to 15 show a first reference example of the locking ring . In the locking ring 5B, the inclination angle θ1 of the first biting tooth 52 with respect to the axis of the locking ring 5B is smaller than the inclination angle θ2 of the second biting tooth 53. Moreover, the circle in contact with the center in the axial direction of each first biting tooth 52 and the circle in contact with the center in the width direction of the second biting tooth 53 are set to have the same diameter. However, since the protrusion amount of the first biting tooth 52 is larger than the protrusion amount of the second biting tooth 53, the first biting tooth 52 bites into the resin tube T in front of the second biting tooth 53 over its entire width. This point is the same as in the above-described embodiment.

16 and 17 show a second reference example of the locking ring . In this locking ring 5C, the tip surfaces of the first and second biting teeth 52, 53 are formed by arcuate surfaces centering on the axis of the locking ring 5C. You may form the front end surface of the 1st, 2nd bite teeth 52 and 53 by the plane orthogonal to the radial line of the base 51 which passes through the center of each width direction.

18 and 19 show a third reference example of the locking ring . In the locking ring 5D, the first and second biting teeth are formed such that the center portions in the width direction of the front end surfaces of the first and second biting teeth 52 and 53 are recessed toward the radially outer side of the locking ring 5D. The front end surfaces of 52 and 53 are formed in an obtuse triangular shape.

20 and 21 show a fourth reference example of the locking ring . In this locking ring 5E, the front end surface of the first biting tooth 52 is formed by an arc surface or a plane, like the first biting tooth 52 of the locking ring 5C shown in FIGS. The distal end surface of the biting tooth 53 is formed in an obtuse triangular shape like the second biting tooth 53 of the locking ring 5D shown in FIGS. Of course, conversely, the tip surface of the first biting tooth 52 may be formed in an obtuse triangular shape, and the tip surface of the second biting tooth 53 may be formed by an arc surface or a flat surface.

22 and 23 show a fifth reference example of the locking ring . In this locking ring 5F, the tip surface of the first biting tooth 52 is formed in a trapezoidal shape so as to be recessed toward the outside in the radial direction of the locking ring 5F. On the contrary, you may form in the trapezoidal shape so that the front end surface of the 2nd bite teeth 53 may be dented toward the radial direction outer side of the locking ring 5F.

24 and 25 show a sixth reference example of the locking ring . In the locking ring 5G, two second biting teeth 53, 53 are arranged between the first biting teeth 52, 52.

26 and 27 show a seventh reference example of the locking ring . In this locking ring 5 </ b> I, the radius of curvature of the arc surface constituting the tip surface of the second biting tooth 53 is smaller than the radius of curvature of the arc surface constituting the tip surface of the first biting tooth 52. In addition, the diameter of the circle in contact with the center in the width direction of each second biting tooth 53 is the same as the diameter of the circle in contact with the center in the width direction of each first biting tooth 52. That is, the protruding amount of the central portion of the first biting tooth 52 and the protruding amount of the central portion of the second biting tooth 53 are the same.

28 and 29 show an eighth reference example of the locking ring . In this locking ring 51, the radius of curvature of the arc surface constituting the tip surface of the second biting tooth 53 is smaller than the radius of curvature of the arc surface constituting the tip surface of the first biting tooth 52. In addition, the diameter of the circle in contact with the center in the width direction of each second biting tooth 53 is the same as the diameter of the circle in contact with the center in the width direction of each first biting tooth 52. That is, the protruding amount of the central portion of the first biting tooth 52 and the protruding amount of the central portion of the second biting tooth 53 are the same.

In addition, this invention is not limited to said embodiment, In the range which does not deviate from the summary, it can change suitably.
For example, in the above-described embodiment, the inner cylinder portion 2c that divides the passage hole 2a into the outer hole portion 2d and the inner hole portion 2e is formed on the inner periphery of the passage hole 2a. Need not be formed. When the inner cylinder portion 2c is not formed, the seal member 3 is provided on the inner peripheral surface of the passage hole 2a, and the inner peripheral surface of the passage hole 2a and the outer peripheral surface of the resin tube T are sealed by the seal member 3 between them. Is done.

It is sectional drawing which shows one Embodiment of the pipe joint which concerns on this invention in the state before connecting a resin pipe. It is a top view of the latching ring used in the embodiment. It is a front view of the locking ring. It is a perspective view of the locking ring. It is sectional drawing which shows the same embodiment in the state inserted in the outer hole part until the resin pipe | tube contact | abuts to the guide member. It is sectional drawing which shows the same embodiment in the state inserted until the resin pipe | tube contact | abuts via the guide member at the bottom part of the outer hole part. It is sectional drawing which shows the embodiment in the state which pulled back the resin pipe a little. It is sectional drawing which shows the embodiment in the state which pulled back the resin pipe | tube further. It is an enlarged plan view which shows the front-end | tip part of the resin pipe in which the 1st, 2nd bite mark was formed with the latching ring of the embodiment. It is an enlarged plan view which shows the front-end | tip part of the resin pipe in which the biting trace was formed with the latching ring of the conventional pipe joint. It is a top view which shows the 1st modification of the latching ring used in the pipe joint which concerns on this invention. It is a front view which shows the 1st modification. It is a top view which shows the 1st reference example of the locking ring used in a pipe joint. It is a front view which shows the 1st reference example . It is an expanded sectional view which follows the XX line of FIG. It is a top view which shows the 2nd reference example of the locking ring used in a pipe joint. It is a front view showing the second reference example . It is a top view which shows the 3rd reference example of the locking ring used in a pipe joint. It is a front view which shows the 3rd reference example . It is a top view which shows the 4th reference example of the locking ring used in a pipe joint. It is a front view showing the fourth reference example . It is a top view which shows the 5th reference example of the locking ring used in a pipe joint. It is a front view which shows the 5th reference example . It is a top view which shows the 6th reference example of the locking ring used in a pipe joint. It is a front view which shows the 6th reference example . It is a top view which shows the 7th reference example of the locking ring used in a pipe joint. It is a front view which shows the 7th reference example . It is a top view which shows the 8th reference example of the locking ring used in a pipe joint. It is a front view which shows the 8th reference example .

Explanation of symbols

T Resin pipe 1 Pipe joint 2 Joint body 2a Passage hole 5 Lock ring 5A Lock ring 5B Lock ring 5C Lock ring 5D Lock ring 5E Lock ring 5F Lock ring 5G Lock ring 5H Lock ring 5I Stop ring 52 first bite (bite teeth)
53 Second bite teeth (bite teeth)

Claims (3)

A pipe body having a passage hole penetrating the inside and having at least an outer peripheral portion made of resin is provided at a joint body inserted into the passage hole from one end opening thereof, and at one end portion inside the passage hole. An annular base provided in a state in which the locking ring is prevented from moving beyond a predetermined range in the longitudinal direction in the passage hole, and an inner peripheral portion of the base Formed and having a number of biting teeth protruding from the base in a state inclined toward the inside in the radial direction toward the front in the insertion direction of the tube, and the tube from the one end opening of the passage hole After being inserted into the locking ring, when pulled back to the outside of the passage hole, the biting teeth bite into the outer peripheral surface of the pipe body, whereby the pipe body is connected to the joint body in a retaining state. In the joint,
When the two biting teeth adjacent in the circumferential direction of the locking ring are first and second biting teeth, respectively, the first and second biting teeth are alternately arranged in the circumferential direction of the locking ring,
The one end portion and the other end portion of the first biting tooth so that ends adjacent to each other in the circumferential direction of the first and second biting teeth respectively bite into the tube body at different positions in the longitudinal direction. Each protruding amount from the base is set larger than each protruding amount from the base of each end of the second biting tooth adjacent to the one end and the other end of the first biting tooth, respectively.
The first and second biting teeth are formed such that the center portion in the circumferential direction of the locking ring protrudes larger than both end portions, and the protruding amount of the center portion of the first biting tooth is the second biting tooth. Set larger than the amount of protrusion at the center of the tooth,
The diameter of the circle in contact with the circumferential central portion of each first biting tooth is set to be smaller than the outer diameter of the resin tube,
The diameter of the circle in contact with the circumferential center of each second biting tooth is set to be larger than the outer diameter of the resin tube,
The pipe joint according to claim 1, wherein when the resin tube in which the first biting tooth has bitten is pulled back, the base portion is elastically deformed, whereby the second biting tooth bites into the resin tube.
2. Each of the leading ends in the protruding direction of the first and second biting teeth is formed by a convex curved surface that bulges inward in the radial direction of the locking ring. Pipe fittings. 3. The tube according to claim 1, wherein an inclination angle of the first biting tooth with respect to the axis of the base is set to be smaller than an inclination angle of the second biting tooth with respect to the axis of the base. Fittings.

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