Pipe joint

Abstract

To provide a pipe joint capable of suppressing breakage of the pipe joint and suppressing molding failure.SOLUTION: A pipe joint 1 has a body part 2 and a branch part 3, and has, at an intersection 6 between the body part 2 and the branch part 3, a stopper step part 4 which receives a pipe end surface 51a of a first connection pipe 51 fitted to a socket 11 of the body part 2 and receives a pipe end surface 52a of a second connection pipe 52 fitted to a socket 21 of the branch part 3. In at least either the socket 11 of the body part 2 or the socket 21 of the branch part 3 of the pipe joint 1, a pipe end surface of a connection pipe engaging one of the sockets overlaps an outer peripheral surface provided for the other socket in an axial direction of one of the sockets.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a pipe joint. [Background technology]

[0002] Pipe fittings such as tee fittings with a branch between two receiving ports are used in water supply and plant piping. When a connecting pipe is fitted into the receiving port of a pipe fitting and positive hydrostatic pressure is repeatedly applied inside the pipe, stress concentrates at the corner on the inside of the branch in the direction of branching. This stress concentration at the corner causes cracks to form inside the corner. If the crack grows to the outside of the corner, there is a risk that the pipe fitting will be destroyed.

[0003] One known solution to this problem is to increase the wall thickness of the pipe joint, which can reduce or prevent fatigue failure in the corners over the long term when stress is repeatedly applied to the corners (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-203430 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the pipe joint is made thicker, there is a risk that the resin will shrink when solidifying, for example, when the pipe joint is molded from resin. If the resin shrinks, localized dents or the like will occur in the pipe joint due to shrinkage, increasing the possibility of defective molding of the pipe joint.

[0006] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a pipe joint that can suppress breakage of the pipe joint and suppress molding defects. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention proposes the following means. A pipe fitting according to one embodiment of the present invention has a main body portion having two receiving ports at both ends, and a branch portion branching off from between the two receiving ports on the main body portion, and has a stopper step portion at the intersection of the main body portion and the branch portion that receives the pipe end face of a connecting pipe to be fitted into the receiving port and also receives the pipe end face of a connecting pipe to be fitted into the receiving port of the branch portion, and in at least one of the receiving ports of the main body portion and the receiving port of the branch portion, the pipe end face of the connecting pipe fitted into one of the receiving ports overlaps in the axial direction of the one of the receiving ports with the outer peripheral surface provided on the other of the receiving ports. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a pipe joint that can suppress breakage of the pipe joint and suppress molding defects. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing a state in which a connecting pipe is connected to a pipe joint according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing the pipe joint of FIG. 1. [Figure 3] 4 is a cross-sectional view illustrating the overlap of connecting pipes fitted into main bodies at an intersection of the pipe joint according to the first embodiment. FIG. [Figure 4] 5 is a cross-sectional view illustrating the shape of a stopper step portion relative to a connecting pipe fitted into a main body portion at an intersection of the pipe joint according to the first embodiment. FIG. [Figure 5] 5 is a cross-sectional view illustrating the overlap of connecting pipes fitted into branched portions at an intersection of the pipe joint according to the first embodiment. FIG. [Figure 6] 5 is a cross-sectional view illustrating the shape of a stopper step portion for a connecting pipe fitted into a branch portion at an intersection of the pipe joint according to the first embodiment. FIG. [Figure 7] FIG. 10 is a cross-sectional view showing a state in which a connecting pipe is connected to a pipe joint according to a second embodiment. [Figure 8] FIG. 10 is a cross-sectional view illustrating a stopper step portion at an intersection of a pipe joint according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a pipe joint according to one embodiment of the present invention will be described with reference to the drawings.

[0011] [First embodiment] As shown in Figures 1 and 2, pipe fitting 1 is a 90-degree tee made of synthetic resin, used for example in water supply or plant piping. Pipe fitting 1 has, for example, a main body 2, a branching portion 3, and a stopper step portion 4. Main body 2 is a main pipe formed in a straight pipe shape. Main body 2 has two sockets 11 and a main body center 12.

[0012] The two sockets 11 are provided at both ends of the main body center 12. The two sockets 11 have outer peripheral surfaces 11a. The outer peripheral surface 11a is formed, for example, with a draft angle such that the outer diameter gradually decreases from the main body center 12 toward the end 11b along a first axis (axis) Lo1. The first axis Lo1 indicates the axis of the main body portion 2 (the axis of the sockets 11). The two sockets 11 are connected to the main body center 12. The main body center 12 is provided between the two sockets 11 in the direction of the first axis Lo1.

[0013] The thickness of the main body center 12 is greater than the thickness of the socket 11. The inner circumferential surface 12a of the main body center 12 is provided along the first axis Lo1. The inner circumferential surface 11c of the socket 11 is formed, for example, with a draft angle such that the inner diameter gradually increases from the main body center 12 side toward the end 11b along the first axis Lo1. The inner diameter (caliber) of the socket 11 on the end 11b side is, for example, 50 mm or less. A first connecting pipe (connecting pipe) 51 is connected to the socket 11 of the main body 2 with an adhesive in a fitted state. For example, a vinyl chloride pipe is used as the first connecting pipe 51.

[0014] An annular body step surface 14 is provided between the inner circumferential surface 11c of the socket 11 and the inner circumferential surface 12a of the body center 12. The annular body step surface 14 is provided at an angle with respect to the first axis Lo1 so that the inner diameter gradually increases from the inner circumferential surface 11c of the socket 11 toward the inner circumferential surface 12a of the body center 12 along the first axis Lo1. The body step surface 14 receives the pipe end surface 51a of the first connecting pipe 51 fitted into the socket 11 of the body portion 2.

[0015] The branch portion 3 is provided in the body center 12 of the main body 2. The branch portion 3 branches off between the two sockets 11 at the body center 12 so as to be perpendicular to the first axis Lo1 at a 90-degree angle. The branch portion 3 has a socket 21. The socket 21 is provided with an outer peripheral surface 21a. The outer peripheral surface 21a is formed, for example, with a draft such that the outer diameter gradually decreases from the body center 12 side toward the end 21b along the second axis (axis) Lo2. The second axis Lo2 indicates the axis of the branch portion 3.

[0016] The inner peripheral surface 21c of the socket 21 is formed, for example, with a draft gradient such that the inner diameter gradually increases from the main body center 12 toward the end 21b along the second axis Lo2. The inner diameter (caliber) of the socket 21 on the end 21b side is 50 mm or less. The inner diameter of the socket 21 in the branching portion 3 is smaller than the inner diameter of the socket 11 in the main body 2. A second connecting pipe (connecting pipe) 52 is connected to the socket 21 of the branching portion 3 with an adhesive in a fitted state. The second connecting pipe 52 may be, for example, the same vinyl chloride pipe as the first connecting pipe 51.

[0017] A first step surface 31 and a first peripheral surface 32 are provided between the inner peripheral surface 21c of the branch portion 3 and the inner peripheral surface 12a of the main body center 12. The first peripheral surface 32 is provided at the intersection 6 between the main body 2 and the branch portion 3. The first peripheral surface 32 is provided in an annular shape along the second axis Lo2. The first peripheral surface 32 is formed with a smaller diameter than the inner peripheral surface 21c of the socket 21 in the branch portion 3.

[0018] The first step surface 31 is provided at the intersection 6 between the main body 2 and the branching portion 3. The first step surface 31 is provided in an annular shape between the inner circumferential surface 21c of the socket 21 and the first peripheral surface 32. The first step surface 31 is formed in an inclined shape with respect to the second axis Lo2 so that the inner diameter gradually decreases from the first peripheral surface 32 toward the inner circumferential surface 21c of the socket 21 along the second axis Lo2. The first step surface 31 receives a pipe end surface 52a of the second connecting pipe 52 fitted into the socket 21 of the branching portion 3. The branching portion 3 is connected to the main body center 12 by the annular portion formed by the first peripheral surface 32 and the first step surface 31.

[0019] As shown in Figures 1 and 3, the stopper step 4 is provided inside the pipe fitting 1 at the intersection 6 between the main body portion 2 and the branch portion 3. The stopper step 4 has a first step surface 31, a first circumferential surface (inner circumferential surface) 32, a second step surface 33, and a second circumferential surface (inner circumferential surface) 34. The second step surface 33 is provided at a portion of the main body step surface 14 that corresponds to the intersection 6. The second circumferential surface 34 is formed at a portion of the inner circumferential surface 12a of the main body center 12 that corresponds to the intersection 6.

[0020] The stopper step 4 is provided with a first step surface 31, a first circumferential surface 32, a second step surface 33, and a second circumferential surface 34 so as to protrude into the inside of the pipe fitting 1 at the intersection 6. The tip of the stopper step 4 is provided in a tapered shape with the first circumferential surface 32 and the second circumferential surface 34. The stopper step 4 receives, on the second step surface 33, the pipe end surface 51a of the first connecting pipe 51 that fits into the socket 11 of the main body 2. In addition, the stopper step 4 receives, on the first step surface 31, the pipe end surface 52a of the second connecting pipe 52 that fits into the socket 21 of the branching section 3.

[0021] The first connecting pipe 51 is fitted into the socket 11 of the main body 2. In this state, the pipe end surface 51a of the first connecting pipe 51 overlaps with the outer periphery intersection point P1 in the direction of the first axis Lo1. The outer periphery intersection point P1 is the position where the first extension line L1 and the second extension line L2 intersect. The first extension line L1 is a line extending from the outer periphery surface 11a of the socket 11 of the main body 2 toward the branching section 3. The second extension line L2 is a line extending from the outer periphery surface 21a of the socket 21 of the branching section 3 toward the main body 2. Therefore, the outer periphery intersection point P1 indicates the outer periphery surface 21a of the socket 21 of the branching section 3 in the direction of the first axis Lo1.

[0022] This allows the pipe end surface 51a of the first connecting pipe 51 to overlap the outer peripheral surface 21a of the receiving port 21 of the branching section 3 by a length A1 (A) in the direction of the first axis Lo1. Hereinafter, the length A1 by which the pipe end surface 51a of the first connecting pipe 51 overlaps with the branching section 3 will be referred to as the "overlap length A1." In the first embodiment, an example will be described in which the "outer peripheral surface 21a of the socket 21 in the direction of the first axis Lo1" is indicated by the outer peripheral intersection point P1, but this is not limited to this. As another example, for example, the "outer peripheral surface 21a of the end portion 21b of the socket 21" may be the outer peripheral surface 21a of the socket 21.

[0023] 1 and 4, in the socket 11 of the main body 2, the second circumferential surface 34 of the stopper step 4 is located radially inward by a step a1(a) with respect to the inner circumferential surface 11c of the socket 11. Here, if a draft angle is formed on the inner circumferential surface 11c of the socket 11 along the first axis Lo1, the position 11d on the inner circumferential surface 11c closest to the stopper step 4 (i.e., the position on the joint center side) is defined as the inner circumferential surface 11c of the socket 11. Hereinafter, the radial step a1 between the second circumferential surface 34 of the stopper step 4 and the inner circumferential surface 11c of the socket 11 will be described as the "stopper step a1."

[0024] Additionally, in the socket 11 of the main body 2, the third circumferential surface 34 of the stopper step 4 is determined to have a width b1(b) in the direction of the first axis Lo1. The width b1 is the width in the direction of the first axis Lo1 from the tip 4a of the stopper step 4 to the first intersection point P2. The tip 4a of the stopper step 4 is the position where the first circumferential surface 32 and the second circumferential surface 34 of the stopper step 4 intersect. The first intersection point P2 is the position where the third extension line L3 and the fourth extension line L4 intersect. The third extension line L3 is a line that extends from the second peripheral surface 34 toward the receiving opening 11 of the main body 2. The fourth extension line L4 is a line that extends from the second step surface 33 toward the tip 4a of the stopper step 4. Hereinafter, the width b1 of the second peripheral surface 34 of the stopper step 4 in the direction of the first axis Lo1 will be described as the "stopper width b1."

[0025] As shown in FIGS. 1 to 4, the pipe fitting 1 has an overlap length A1, a step a1, and a width b1, which have the following relationship when viewed in a cross section along the axis of the pipe fitting 1 (a cross section along both the first axis Lo1 and the second axis Lo2): a1:b1:A1=1:2~4:3.6~5.6 It is formed so as to satisfy the following. That is, the overlap length A1, the step a1, and the width b1 are: a1:b1=1:2~4 is satisfied, Satisfies a1:A1=1:3.6~5.6. The reason for setting a1:b1:A1=1:2-4:3.6-5.6 will be explained below with reference to Figs. 1 to 4 and Table 1. Table 1 shows the calculation results of the local maximum stresses obtained in Examples 1 to 3 and Comparative Examples 1 to 3.

[0026] [Table 1]

[0027] Using the general-purpose finite element analysis software Abaqus CAE 2022 (Dassault Systèmes), a 3D model of a stand-alone tee pipe fitting 1 with adjustable step height a1, width b1, and overlap length A1 was created. A 3D model was also created of the pipe fitting 1 with a first connecting pipe 51 mated and connected to the two sockets 11, and a second connecting pipe 52 mated and connected to the socket 21. Hereinafter, the pipe fitting 1 as a stand-alone unit may be referred to as a "pipe-less pipe fitting." Furthermore, the pipe fitting 1 with the first connecting pipe 51 and the second connecting pipe 52 mated and connected may be referred to as a "pipe-with pipe fitting" in its actual use state.

[0028] In the three-dimensional models of both the pipe joint without pipes and the pipe joint with pipes, the local maximum stresses were calculated by nonlinear analysis using the process automation software Isight 2022 (Dassault Systemes). Specifically, for the 3D model of the pipe-less pipe fitting, the local maximum stress generated when an internal pressure of 1.0 MPa was applied to the entire inner surface of the pipe fitting 1, including the inner circumferential surface 11c of the socket 11 in the main body 2 and the inner circumferential surface 21c of the socket 21 in the branch portion 3, was calculated by nonlinear analysis. On the other hand, for the 3D model of the pipe-with pipe fitting, the local maximum stress generated when an internal pressure of 1.0 MPa was applied to the entire portions of the inner surfaces of the pipe fitting 1, the first connecting pipe 51, and the second connecting pipe 5 that were located inside the pipe fitting 1, after the pipe fitting 1, the first connecting pipe 51, and the second connecting pipe 52 had been integrated, was calculated by nonlinear analysis. Hereinafter, the internal pressure of 1.0 MPa applied to the entire inner surface as described above in each model may be simply referred to as "internal pressure of 1.0 MPa."

[0029] Example 1 For a pipe fitting 1 in which the diameter of the socket 11 of the main body 2 is 25 mm and the diameter of the socket 21 of the branch 3 is 20 mm, the approximate ranges defined by the JIS standard are as follows: That is, the outer diameter D1 of the socket 11 in the main body 2 was 40 mm, and the outer diameter D2 of the socket 21 in the branch 3 was 33 mm. The socket height H1 of the main body 2 was 56.5 mm, and the socket height H2 of the branch 3 was 54.5 mm. The inner diameter d1 of the socket 11 on the end 11b side of the main body 2 was 32.55 mm, and the inner diameter d2 of the socket 11 on the joint center side of the main body 2 was 31.37 mm. The inner diameter d3 of the socket 21 on the end 21b side of the branch 3 was 26.45 mm, and the inner diameter d4 of the socket 21 on the joint center side of the branch 3 was 25.42 mm. In addition, the ratios a1:b1:A1 were 1:2:5.6.

[0030] Under these conditions, an internal pressure of 1.0 MPa was applied to both the 3D models of the pipe joint without pipes and the pipe joint with pipes. The analysis results for both 3D models are as follows: That is, the maximum local stress was 19.25 MPa for the pipe joint without a pipe and 6.947 MPa for the pipe joint with a pipe.

[0031] Example 2 For a general shape equivalent to that of Example 1, a1:b1:A1=1:3:4.6. Under these conditions, an internal pressure of 1.0 MPa was applied to both the 3D models of the pipe joint without pipes and the pipe joint with pipes. The analysis results for both 3D models are as follows: That is, the maximum local stress was 18.35 MPa for the pipe joint without a pipe and 7.372 MPa for the pipe joint with a pipe.

[0032] Example 3 For a general shape equivalent to that of Example 1, a1:b1:A1=1:4:3.6. Under these conditions, an internal pressure of 1.0 MPa was applied to both the 3D models of the pipe joint without pipes and the pipe joint with pipes. The analysis results for both 3D models are as follows: That is, the maximum local stress was 17.93 MPa for the pipe joint without a pipe and 7.910 MPa for the pipe joint with a pipe.

[0033] (Comparative Example 1) For a general shape equivalent to that of Example 1, a1:b1:A1=1:2:1.8. Under these conditions, an internal pressure of 1.0 MPa was applied to both the 3D models of the pipe joint without pipes and the pipe joint with pipes. The analysis results for both 3D models are as follows: That is, the maximum local stress was 18.20 MPa for the pipe joint without a pipe and 8.683 MPa for the pipe joint with a pipe.

[0034] (Comparative Example 2) For a general shape equivalent to that of Example 1, a1:b1:A1=1:0.143:0.94. Under these conditions, an internal pressure of 1.0 MPa was applied to both the 3D models of the pipe joint without pipes and the pipe joint with pipes. The analysis results for both 3D models are as follows: That is, the maximum local stress was 28.80 MPa for the pipe joint without a pipe and 15.76 MPa for the pipe joint with a pipe.

[0035] (Comparative Example 3) For a general shape equivalent to that of Example 1, a1:b1:A1=1:1.2:0.32. Under these conditions, an internal pressure of 1.0 MPa was applied to both the 3D models of the pipe joint without pipes and the pipe joint with pipes. The analysis results for both 3D models are as follows: That is, the maximum local stress was 15.23 MPa for the pipe joint without a pipe and 9.88 MPa for the pipe joint with a pipe.

[0036] The calculation results of the local maximum stress obtained in Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1. It can be seen from Table 1 that in a pipe-equipped fitting in an actual use state, the local maximum stress can be kept small by satisfying a1:b1:A1 = 1:2-4:3.6-5.6. That is, by satisfying a1:b1=1:2 to 4 and a1:A1=1:3.6 to 5.6, the local maximum stress in the pipe-connector can be kept small.

[0037] Next, the relationship between the overlap length A2, the step a2, and the width b2 at the receiving port of the branch portion 3 will be described with reference to FIGS. 1 and 5, the second connecting pipe 52 is fitted into the socket 21 of the branching portion 3. In this state, the pipe end surface 52a of the second connecting pipe 52 overlaps with the outer periphery intersection point P1 in the direction of the second axis Lo2. The outer periphery intersection point P1 indicates the outer periphery surface 11a of the socket 11 of the main body portion 2 in the direction of the second axis Lo2.

[0038] This allows the pipe end surface 52a of the second connecting pipe 52 to overlap the outer peripheral surface 11a of the socket 11 of the main body 2 by a length A2 (A) in the direction of the second axis Lo2. Hereinafter, the length A2 by which the pipe end surface 52a of the second connecting pipe 52 overlaps with the main body 2 will be referred to as the "overlap length A2." In the first embodiment, an example will be described in which the "outer peripheral surface 11a of the socket 11 in the direction of the second axis Lo2" is indicated by the outer peripheral intersection point P1, but this is not limited to this. As another example, for example, the "outer peripheral surface 11a of the end portion 11b of the main body portion 2" may be the outer peripheral surface 11a of the socket 11.

[0039] 1 and 6, in the socket 21 of the branch portion 3, the first circumferential surface 32 of the stopper step 4 is located radially inward from the inner circumferential surface 21c of the socket 21 by a step a2(a). Here, if a draft angle is formed on the inner circumferential surface 21c of the socket 21 along the second axis Lo2, the position 21d on the inner circumferential surface 21c closest to the stopper step 4 (i.e., the position toward the center of the joint) is defined as the inner circumferential surface 21c of the socket 21. Hereinafter, the radial step a2 between the first circumferential surface 32 of the stopper step 4 and the inner circumferential surface 21c of the socket 21 will be referred to as the "stopper step a2."

[0040] Furthermore, at the receiving port 21 of the branching portion 3, the first peripheral surface 32 of the stopper step 4 is determined to have a width b2(b) in the direction of the second axis Lo2. The width b2 is the width from the tip 4a of the stopper step 4 to the second intersection point P3 in the direction of the second axis Lo2. The second intersection point P3 is the position where the fifth extension line L5 and the sixth extension line L6 intersect. The fifth extension line L5 is a line extending from the first peripheral surface 32 toward the receiving port 21 of the branching portion 3. The sixth extension line L6 is a line extending from the first step surface 31 toward the tip 4a of the stopper step 4. Hereinafter, the width b2 of the first peripheral surface 32 of the stopper step 4 in the direction of the second axis Lo2 will be referred to as the "stopper width b2."

[0041] As shown in FIGS. 3 to 6, in the pipe fitting 1, the relationship between the overlap length A2, the step a2, and the width b2 is similar to the relationship between the overlap length A1, the step a1, and the width b1, and, for example, in a cross-sectional view along the axis of the pipe fitting 1 (a cross-sectional view along both the first axis Lo1 and the second axis Lo2), a2:b2:A2=1:2~4:3.6~5.6 It is formed so as to satisfy the following. That is, the overlap length A2, the step a2, and the width b2 are a2:b2=1:2~4 is satisfied, Satisfies a2:A2=1:3.6~5.6.

[0042] Thus, the tee pipe fitting 1 satisfies a1:b1:A1 = 1:2-4:3.6-5.6 and a2:b2:A2 = 1:2-4:3.6-5.6, which allows the maximum local stress to be kept low in the pipe-equipped pipe fitting during actual use. That is, by satisfying a1:b1=1:2 to 4, a1:A1=1:3.6 to 5.6, and a2:b2=1:2 to 4, a2:A2=1:3.6 to 5.6, the local maximum stress in the pipe-connector can be kept small.

[0043] According to the pipe joint 1 of the first embodiment described above, the following actions and effects can be obtained. 1 and 3, at the socket 11 of the main body 2, the pipe end surface 51a of the first connecting pipe 51 fitted into the socket 11 is made to overlap the outer peripheral surface 21a of the socket 21 at the branch portion 3 in the direction of the first axis Lo1. Therefore, the first connecting pipe 51 can reinforce the vicinity of the stopper step portion 4 at the intersection 6. This makes it possible to reduce or prevent fatigue failure at the intersection 6 over the long term while preventing the wall thickness of the pipe fitting 1 from increasing. Therefore, failure of the pipe fitting 1 can be suppressed, and molding defects of the pipe fitting 1 can be suppressed.

[0044] 1 and 5, at the socket 21 of the branch portion 3, the pipe end surface 52a of the second connecting pipe 52 fitted into the socket 21 overlaps the outer peripheral surface 11a of the socket 11 of the main body 2 in the direction of the second axis Lo2. This allows the second connecting pipe 52 to reinforce the vicinity of the stopper step portion 4 at the intersection 6. This makes it possible to reduce or prevent fatigue failure at the intersection 6 over the long term while preventing the wall thickness of the pipe fitting 1 from increasing. This therefore prevents failure of the pipe fitting 1 and reduces molding defects of the pipe fitting 1.

[0045] In the first embodiment, an example is described in which the pipe end surface 51a of the first connecting pipe 51 overlaps the outer peripheral surface 21a at the socket 11 of the main body 2, and the pipe end surface 52a of the second connecting pipe 52 overlaps the outer peripheral surface 11a at the socket 21 of the branching section 3, but this is not limitative. It is sufficient to satisfy the overlap configuration at least in one of the socket 11 of the main body 2 and the socket 21 of the branching section 3.

[0046] 1, 3, and 4, in the receiving port 11 of the main body 2, the relationship between the stopper step a1, the stopper width b1, and the overlap length A1 is as follows: a1:b1:A1=1:2~4:3.6~5.6 It was decided. By setting the overlap length A1 to 3.6 or more, the overlap length A1 can be increased. This allows the first connecting pipe 51 to reinforce the vicinity of the stopper step portion 4 at the intersection 6. Furthermore, by setting the overlap length A1 to 5.6 or less, the stopper width b1 can be ensured to be in the range of 2 to 4. Therefore, the stopper width b1 can be increased. By satisfying a1:b1:A1=1:2-4:3.6-5.6, the vicinity of the stopper step 4 at the intersection 6 can be reinforced by the first connecting pipe 51 and the stopper step 4.

[0047] Furthermore, as shown in Figs. 1, 5 and 6, in the receiving port 21 of the branching portion 3, the relationship between the stopper step a2, the stopper width b2 and the overlap length A2 is a2:b2:A2=1:2~4:3.6~5.6 It was decided. By setting the overlap length A2 to 3.6 or more, the overlap length A2 can be increased. This allows the second connecting pipe 52 to reinforce the vicinity of the stopper step portion 4 at the intersection 6. Furthermore, by setting the overlap length A2 to 5.6 or less, the stopper width b2 can be ensured to be in the range of 2 to 4. Therefore, the stopper width b2 can be increased. By satisfying a2:b2:A2=1:2-4:3.6-5.6, the vicinity of the stopper step 4 at the intersection 6 can be reinforced by the second connecting pipe 52 and the stopper step 4.

[0048] In the first embodiment, an example will be described in which the receiving port 11 of the main body 2 satisfies a1:b1:A1 = 1:2 to 4:3.6 to 5.6, and the receiving port 21 of the branching portion 3 satisfies a2:b2:A2 = 1:2 to 4:3.6 to 5.6, but the present invention is not limited to this. It is sufficient that the relationships among the stopper step, stopper width, and overlap length are satisfied in at least one of the receiving port 11 of the main body 2 and the receiving port 21 of the branching portion 3.

[0049] 1, 3, and 4, when the inner diameters of the socket 11 of the main body 2 and the socket 21 of the branch portion 3 are 50 mm or less, the wall thickness of the intersection portion 6 can be kept relatively small. Therefore, by satisfying the relationship a1:b1:A1 = 1:2-4:3.6-5.6, damage to the pipe fitting 1 can be appropriately suppressed. Furthermore, as shown in Figs. 1, 5 and 6, by satisfying the relationship a2:b2:A2 = 1:2-4:3.6-5.6, breakage of the pipe fitting 1 can be appropriately suppressed.

[0050] 1, 3, and 4, when the inner diameter of the socket 21 in the branch portion 3 is smaller than the inner diameter of the socket 11 in the main body portion 2, the thickness of the intersection portion 6 can be further reduced. Therefore, by satisfying the relationship a1:b1:A1 = 1:2-4:3.6-5.6, damage to the pipe fitting 1 can be more appropriately prevented. Furthermore, as shown in Figs. 1, 5 and 6, by satisfying the relationship a2:b2:A2 = 1:2-4:3.6-5.6, breakage of the pipe fitting 1 can be appropriately suppressed.

[0051] [Second embodiment] Next, a pipe fitting 100 according to a second embodiment will be described with reference to Figures 7 and 8. In the second embodiment, the same or similar members as those in the pipe fitting 1 of the first embodiment will be denoted by the same reference numerals, and detailed description thereof will be omitted. 7 and 8, a pipe fitting 100 according to the second embodiment is a 90-degree elbow made of synthetic resin and used, for example, for water supply or plant piping. The pipe fitting 100 has, for example, two sockets 102, a bent portion 103, and a stopper step portion 104.

[0052] The two sockets 102 are provided at both ends of the bent portion 103. Each of the two sockets 102 has an outer peripheral surface 102a. Hereinafter, one of the two sockets 102 may be referred to as "socket 102A" and the other as "socket 102B." The outer peripheral surface 102a of socket 102A is formed with a draft angle such that the outer diameter gradually decreases from the bent portion 103 side toward the end 102b along a first axis (axis) Lo3. The outer peripheral surface 102a of socket 102B is formed with a draft angle such that the outer diameter gradually decreases from the bent portion 103 side toward the end 102b along a second axis (axis) Lo4. The first axis Lo3 indicates the axis of socket 102A. The second axis Lo4 indicates the axis of socket 102B.

[0053] The two sockets 102 are connected to a bent portion 103. The bent portion 103 is provided between the two sockets 102. The thickness of the bent portion 103 is formed to be greater than the thickness of the sockets 102. The inner circumferential surface 102c of socket 102A is formed, for example, with a draft angle such that the inner diameter gradually increases from the bent portion 103 side toward the end 102b along the first axis Lo3. The inner circumferential surface 102c of socket 102B is formed, for example, with a draft angle such that the inner diameter gradually increases from the bent portion 103 side toward the end 102b along the second axis Lo4. The inner diameter (diameter) of the two sockets 102 on the end 102b side is, for example, 50 mm or less. The two sockets 102 are connected with adhesive in a fitted state to the connecting pipe 151. The connecting pipe 151 is, for example, a vinyl chloride pipe.

[0054] A socket step surface 106 is provided in an annular shape between the inner peripheral surface 102c of the socket 102 and the inner peripheral surface 103a of the bent portion 103. The socket step surface 106 in the socket 102A is provided at an angle with respect to the first axis Lo3 so that the inner diameter gradually increases from the inner peripheral surface 102c of the socket 102 toward the inner peripheral surface 103a of the bent portion 103 along the first axis Lo3. The socket step surface 106 in the socket 102B is provided at an angle with respect to the second axis Lo4 so that the inner diameter gradually increases from the inner peripheral surface 102c of the socket 102 toward the inner peripheral surface 103a of the bent portion 103 along the second axis Lo4. The socket step surface 106 receives a pipe end surface 151a of a connecting pipe 151 fitted into the socket 102.

[0055] The stopper step portion 104 is provided inside the pipe fitting 100 at the intersection 108 of the two sockets 102. The stopper step portion 104 has two step surfaces 121 and two peripheral surfaces (inner peripheral surfaces) 122. The step surfaces 121 are provided at a portion of the socket step surface 106 that corresponds to the intersection 108. The peripheral surfaces 122 are formed at a portion of the inner peripheral surface 103a of the bent portion 103 that corresponds to the intersection 108.

[0056] The stopper step 104 is provided with two step surfaces 121 and two peripheral surfaces 122 so as to protrude into the inside of the pipe fitting 100 at the intersecting portion 108. The tip of the stopper step 104 is provided in a tapered shape with the two peripheral surfaces 122. The stopper step 104 receives the pipe end surface 151a of the connecting pipe 151 that is fitted into the socket 102A. The stopper step 104 also receives the pipe end surface 151a of the connecting pipe 151 that is fitted into the socket 102B.

[0057] The pipe end surface 151a of the connecting pipe 151 fitted into the socket 102A overlaps with the outer periphery intersection point P4 in the direction of the first axis Lo3. The outer periphery intersection point P4 is the position where the first extension line L7 and the second extension line L8 intersect. The first extension line L7 is a line extending from the outer periphery surface 102a of the socket 102A toward the socket 102B. The second extension line L8 is a line extending from the outer periphery surface 102a of the socket 102B toward the socket 102A. Therefore, the outer periphery intersection point P4 indicates the outer periphery surface 102a of the socket 102B in the direction of the first axis Lo3.

[0058] This allows the pipe end surface 151a of the connecting pipe 151 fitted into the socket 102A to overlap the outer circumferential surface 102a of the socket 102B by a length A3(A) in the direction of the first axis Lo3. Hereinafter, the length A3 by which the pipe end surface 151a of the connecting pipe 151 overlaps with the socket 102B in the direction of the first axis Lo3 will be referred to as the "overlap length A3." In the second embodiment, an example will be described in which "the outer peripheral surface 102a of the socket 102B in the direction of the first axis Lo3" is indicated by the outer peripheral intersection point P4, but this is not limiting. As another example, for example, "the outer peripheral surface 102a of the end 102b of the socket 102B" may be the outer peripheral surface 102a of the socket 102B.

[0059] Furthermore, in socket 102A, peripheral surface 122 of stopper step 104 is located radially inward of inner peripheral surface 102c of socket 102A by step a3(a). Here, if inner peripheral surface 102c of socket 102A is formed with a draft along first axis Lo3, position 102d on inner peripheral surface 102c closest to stopper step 104 (i.e., position toward the center of the joint) is defined as inner peripheral surface 102c of socket 102A. Hereinafter, radial step a3 between peripheral surface 122 of stopper step 104 and inner peripheral surface 102c of socket 102A will be described as "stopper step a3."

[0060] Furthermore, in the socket 102A, the peripheral surface 122 of the stopper step 104 is determined to have a width b3(b) in the direction of the first axis Lo3. The width b3 is the width in the direction of the first axis Lo3 from the tip 104a of the stopper step 104 to the intersection point P5. The tip 104a of the stopper step 104 is the position where the two peripheral surfaces 122 of the stopper step 104 intersect. Intersection P5 is the position where the third extension line L9 and the fourth extension line L10 intersect. The third extension line L9 is a line that extends from the peripheral surface 122 toward the receiving port 102A. The fourth extension line L10 is a line that extends from the step surface 121 toward the tip 104a of the stopper step portion 104. Hereinafter, the width b3 of the peripheral surface 122 of the stopper step portion 104 in the direction of the first axis Lo3 will be referred to as the "stopper width b3."

[0061] In the pipe fitting 100, the relationship between the overlap length A3, the step a3, and the width b3 is, for example, as follows in a cross section taken along the axis of the pipe fitting 100 (a cross section taken along both the third axis Lo3 and the fourth axis Lo4): a3:b3:A3=1:2~4:3.6~5.6 It is formed so as to satisfy the following. That is, the overlap length A3, the step a3, and the width b3 are: a3:b3=1:2~4 is satisfied, Satisfies a3:A3=1:3.6~5.6. As a result, according to the pipe fitting 100, similar to the pipe fitting 1 of the first embodiment, it is possible to keep the local maximum stress small in a pipe fitting with a pipe.

[0062] Furthermore, in the socket 102B, the relationship between the overlap length A4, the step a4, and the width b4 of the pipe fitting 100 is similar to the relationship between the overlap length A3, the step a3, and the width b3, and is, for example, as follows when viewed in a cross section along the axis of the pipe fitting 100 (a cross section along both the third axis Lo3 and the fourth axis Lo4): a2:b2:A2=1:2~4:3.6~5.6 It is formed so as to satisfy the following. That is, the overlap length A4, the step a4, and the width b4 are a2:b2=1:2~4 is satisfied, Satisfies a2:A2=1:3.6~5.6. As a result, according to the pipe fitting 100, similar to the pipe fitting 1 of the first embodiment, it is possible to keep the local maximum stress small in a pipe fitting with a pipe.

[0063] According to the pipe joint 100 of the second embodiment described above, the following actions and effects can be obtained. 7 and 8, in the socket 102A, the pipe end surface 151a of the connecting pipe 151 fitted into the socket 102A overlaps with the outer peripheral surface 102a of the socket 102B in the direction of the first axis Lo3. This allows the connecting pipe 151 to reinforce the vicinity of the stopper step portion 104 at the intersection 108. This makes it possible to reduce or prevent fatigue failure at the intersection 108 over the long term while preventing the wall thickness of the pipe fitting 100 from increasing. This therefore prevents failure of the pipe fitting 100 and reduces molding defects of the pipe fitting 100.

[0064] At the socket 102B, the pipe end surface 151a of the connecting pipe 151 fitted into the socket 102B overlaps the outer peripheral surface 102a of the socket 102A in the direction of the second axis Lo4. This allows the connecting pipe 151 to reinforce the vicinity of the stopper step portion 104 at the intersection 108. This makes it possible to reduce or prevent fatigue failure at the intersection 108 over the long term while preventing the pipe fitting 100 from becoming thicker. This therefore prevents failure of the pipe fitting 100 and reduces molding defects of the pipe fitting 100.

[0065] In the second embodiment, an example is described in which pipe end face 151a of connecting pipe 151 overlaps outer peripheral surface 102a in socket 102A and pipe end face 151a of connecting pipe 151 overlaps outer peripheral surface 102a in socket 102B, but this is not limiting. It is sufficient to satisfy the overlapping configuration in at least one of socket 102A and socket 102B.

[0066] In addition, in the receiving port 102A, the relationship between the stopper step a3, the stopper width b3, and the overlap length A3 is a3:b3:A3=1:2~4:3.6~5.6 It was decided. By setting the overlap length A3 to 3.6 or more, the overlap length A3 can be increased. This allows the connection pipe 151 to reinforce the vicinity of the stopper step portion 104 at the intersection 108. Furthermore, by setting the overlap length A3 to 5.6 or less, the stopper width b3 can be secured in the range of 2 to 4. Therefore, the stopper width b3 can be increased. By satisfying a3:b3:A3=1:2-4:3.6-5.6, the vicinity of the stopper step portion 104 at the intersection portion 108 can be reinforced by the connecting pipe 151 and the stopper step portion 104.

[0067] Furthermore, in the receiving port 102B, the relationship between the stopper step a4, the stopper width b4, and the overlap length A4 is a4:b4:A4=1:2~4:3.6~5.6 It was decided. By setting the overlap length A4 to 3.6 or more, the overlap length A4 can be increased. This allows the connection pipe 151 to reinforce the vicinity of the stopper step portion 104 at the intersection 108. Furthermore, by setting the overlap length A4 to 5.6 or less, the stopper width b4 can be secured in the range of 2 to 4. Therefore, the stopper width b4 can be increased. By satisfying a4:b4:A4=1:2-4:3.6-5.6, the vicinity of the stopper step portion 104 at the intersection portion 108 can be reinforced by the connecting pipe 151 and the stopper step portion 104.

[0068] In the second embodiment, an example will be described in which the relationship a3:b3:A3 = 1:2-4:3.6-5.6 is satisfied in the socket 102A, and the relationship a4:b4:A4 = 1:2-4:3.6-5.6 is satisfied in the socket 102B, but this is not limiting. It is sufficient that the relationships of the stopper step, stopper width, and overlap length are satisfied in at least one of the sockets 102A and 102B.

[0069] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0070] In the pipe fitting 1 of the first embodiment, the diameters of the two sockets 11 and the branch socket 21 do not have to be 50 mm or less. In addition, the diameter of the branch socket 21 does not have to be smaller than the diameters of the two sockets 11.

[0071] In addition, the components in this embodiment can be replaced with well-known components as appropriate, without departing from the spirit of the present invention.

[0072] (Addendum) The embodiment can be understood, for example, as follows.

[0073] <1> A pipe fitting according to one embodiment of the present invention has a main body portion having two receiving ports at both ends, and a branch portion branching off from between the two receiving ports on the main body portion, and has a stopper step portion at the intersection of the main body portion and the branch portion that receives the pipe end face of a connecting pipe to be fitted into the receiving port and also receives the pipe end face of a connecting pipe to be fitted into the receiving port of the branch portion, and in at least one of the receiving ports of the main body portion and the receiving port of the branch portion, the pipe end face of the connecting pipe fitted into one of the receiving ports overlaps in the axial direction of the one of the receiving ports with the outer peripheral surface provided on the other of the receiving ports.

[0074] According to the pipe fitting, the pipe end surface of the connecting pipe fitted into one of the sockets overlaps the outer peripheral surface of the other socket in the axial direction of the one socket. This allows the connecting pipe to reinforce the area near the stopper step at the intersection between the main body and the branch. This reduces or prevents fatigue failure at the intersection between the main body and the branch over a long period of time while preventing an increase in the pipe fitting's wall thickness. This reduces failure of the pipe fitting and reduces molding defects in the pipe fitting.

[0075] <2> the above <1> In the pipe fitting according to the above, when the radial step between the inner peripheral surface of the stopper step portion and the inner peripheral surface of the receiving port is defined as a stopper step a, the axial width of the inner peripheral surface of the stopper step portion is defined as a stopper width b, and the overlap length between the pipe end face and the outer peripheral surface is defined as an overlap length A, at least one of the receiving port of the main body portion and the receiving port of the branch portion may satisfy a:b:A=1:2 to 4:3.6 to 5.6.

[0076] According to the pipe fitting, the relationship between the stopper step a, stopper width b, and overlap length A at the receiving port is a:b:A=1:2~4:3.6~5.6 It was decided. By setting the overlap length A to 3.6 or more, the overlap length A can be increased. This allows the connecting pipe to reinforce the vicinity of the stopper step at the intersection between the main body and the branch. Furthermore, by setting the overlap length A to 5.6 or less, the stopper width b can be secured in the range of 2 to 4. Therefore, the stopper width b can be increased. By satisfying a:b:A=1:2-4:3.6-5.6, the vicinity of the stopper step at the intersection of the main body and the branch can be reinforced by the connecting pipe or the stopper step.

[0077] <3> the above <2> In the pipe joint according to the above aspect, the two sockets and the socket of the branch portion may have a diameter of 50 mm or less.

[0078] Here, if the diameters of the two sockets and the socket of the branch section are 50 mm or less, the thickness of the intersecting section can be kept relatively small. Therefore, by satisfying the relationship a:b:A = 1:2-4:3.6-5.6, damage to the pipe joint can be appropriately suppressed.

[0079] <4> the above <2> or <3> In the pipe joint according to the above aspect, the diameter of the socket of the branching portion may be smaller than the diameters of the two sockets.

[0080] If the diameter of the socket at the branch portion is smaller than the diameters of the two sockets, the thickness of the intersecting portion can be further reduced. Therefore, by satisfying the relationship a:b:A = 1:2-4:3.6-5.6, damage to the pipe joint can be more appropriately prevented.

[0081] <5> A pipe fitting according to one embodiment of the present invention is a pipe fitting having two receiving ports at both ends, a bent portion provided between the two receiving ports, and a stopper step portion at the intersection of the two receiving ports that receives the pipe end face of a connecting pipe that is fitted into one of the two receiving ports and also receives the pipe end face of a connecting pipe that is fitted into the other of the two receiving ports, wherein in at least one of the two receiving ports, the pipe end face of the connecting pipe that is fitted into one of the receiving ports overlaps with the outer peripheral surface provided in the other receiving port in the axial direction of the one of the receiving ports.

[0082] According to the pipe fitting, the pipe end surface of the connecting pipe fitted into one socket overlaps the outer peripheral surface of the other socket in the axial direction of the one socket. This allows the connecting pipe to reinforce the area near the stopper step at the intersection of the two sockets. This reduces or prevents fatigue failure at the intersection of the two sockets over the long term while preventing the pipe fitting from becoming too thick. This reduces failure of the pipe fitting and reduces molding defects in the pipe fitting.

[0083] <6> the above <5> In the pipe fitting according to the above, when the radial step between the inner peripheral surface of the stopper step portion and the inner peripheral surface of the receiving port is defined as a stopper step a, the axial width of the inner peripheral surface of the stopper step portion is defined as a stopper width b, and the overlap length between the pipe end face and the outer peripheral surface is defined as an overlap length A, at least one of the two receiving ports may satisfy a:b:A=1:2 to 4:3.6 to 5.6.

[0084] According to the pipe fitting, the relationship between the stopper step a, stopper width b, and overlap length A at the receiving port is a:b:A=1:2~4:3.6~5.6 It was decided. By making the overlap length A 3.6 or more, the overlap length A can be increased. This allows the area near the stopper step at the intersection of the two sockets to be reinforced with the connecting pipe. Also, by making the overlap length A 5.6 or less, the stopper width b can be secured in the range of 2 to 4. Therefore, the stopper width b can be increased. By satisfying a:b:A=1:2-4:3.6-5.6, the area near the stopper step at the intersection of the two sockets can be reinforced with the connecting pipe or the stopper step. [Explanation of symbols]

[0085] 1,100...Pipe fittings 2...Main body 3...Branch 4,104...Stopper step 6,108...Intersection 11...Main body socket 11a...Outer surface of the socket in the main body 11c...inner surface of the socket in the main body 21...Branch socket 21a...Outer surface of the socket at the branch 21c...Inner surface of the receiving port at the branch 31...First stage 32...First peripheral surface (inner peripheral surface of stopper step portion) 33...Second stage 34...Second peripheral surface (inner peripheral surface of stopper step portion) 51...First connecting pipe (connecting pipe) 51a, 52a...Pipe end surface 52...Second connecting pipe (connecting pipe) 102...Socket 102a...Outer surface of socket 102c...Inner surface of socket 103...Bend 121...Step 122... Circumferential surface (inner peripheral surface of stopper step portion) 151...Connecting pipe 151a...Pipe end surface a1, a2, a3...Stopper step (Stopper step a) b1, b2, b3...Stopper width (Stopper width b) A1, A2, A3...Overlap length (overlap length A) Lo1,Lo3…1st axis line (axis line) Lo2,Lo4…Second axis line (axis line)

Claims

1. A pipe fitting having a main body having two sockets at both ends, and a branch portion branching off from the main body between the two sockets, the pipe fitting having a stopper step portion at an intersection between the main body and the branch portion for receiving a pipe end face of a connecting pipe fitted into the sockets and for receiving a pipe end face of a connecting pipe fitted into the socket of the branch portion, At least one of the socket of the main body portion and the socket of the branch portion, A pipe joint, wherein the pipe end surface of the connecting pipe fitted into one of the receiving ports overlaps with the outer peripheral surface provided on the other receiving port in the axial direction of the one receiving port.

2. When the radial step between the inner peripheral surface of the stopper step portion and the inner peripheral surface of the socket is defined as a stopper step a, the axial width of the inner peripheral surface of the stopper step portion is defined as a stopper width b, and the overlap length between the pipe end surface and the outer peripheral surface is defined as an overlap length A, At least one of the socket of the main body portion and the socket of the branch portion, 2. A pipe joint according to claim 1, wherein a:b:A=1:2-4:3.6-5.6 is satisfied.

3. 3. The pipe joint according to claim 2, wherein the diameters of the two sockets and the socket of the branch portion are 50 mm or less.

4. 4. A pipe joint according to claim 2, wherein the diameter of the socket of the branch portion is smaller than the diameters of the two sockets.

5. A pipe fitting having two sockets at both ends, a bent portion provided between the two sockets, and a stopper step portion at the intersection of the two sockets that receives a pipe end face of a connecting pipe that is fitted into one of the two sockets and also receives a pipe end face of a connecting pipe that is fitted into the other of the two sockets, In at least one of the two sockets, A pipe joint, wherein the pipe end surface of the connecting pipe fitted into one of the receiving ports overlaps with the outer peripheral surface provided on the other receiving port in the axial direction of the one receiving port.

6. When the radial step between the inner peripheral surface of the stopper step portion and the inner peripheral surface of the socket is defined as a stopper step a, the axial width of the inner peripheral surface of the stopper step portion is defined as a stopper width b, and the overlap length between the pipe end surface and the outer peripheral surface is defined as an overlap length A, In at least one of the two sockets, 6. A pipe joint according to claim 5, wherein a:b:A=1:2-4:3.6-5.6 is satisfied.

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