Joining structure and joining method for resin pipes
The resin pipe joining structure with a protruding portion and housing space addresses molten resin overflow and efficiency issues, ensuring seamless fusion and prolonged joint lifespan.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- KUBOTA CHEMIX CO LTD
- Filing Date
- 2024-12-26
- Publication Date
- 2026-07-08
Smart Images
Figure 2026114824000001_ABST
Abstract
Description
Technical Field
[0006] , ,
[0001] The present invention relates to a joining structure of resin pipes in which a pair of resin pipes are melt-joined in the axial direction and a method for joining resin pipes.
Background Art
[0002] A method for joining resin pipes is known which prevents the occurrence of beads formed by molten resin overflowing and solidifying in a pair of resin pipes melt-joined in the axial direction.
[0003] For example, in the method for joining synthetic resin pipes of Patent Document 1, an elastic body sandwiched between two plate bodies is inserted into the butting portion of two synthetic resin pipes, and the two plate bodies are pressed by wire operation to expand the diameter of the elastic body. With the elastic body thus expanded in pressure contact with the inner wall of the pipe of the butting portion, the end faces of the synthetic resin pipes in the molten state are pressed axially against each other for fusion bonding. After the formed joint is cooled and solidified, the wire is relaxed and the elastic body is reduced in diameter and removed.
[0004] In Patent Document 1, it is described that when joining synthetic resin pipes by butting, since the elastic body is in pressure contact with the inner wall of the pipe, molten resin does not overflow outside the pipe and does not enter the pipe.
Prior Art Documents
Patent Documents
[0005]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0006] By the way, in the synthetic resin pipe joining method described in Patent Document 1, the inner wall of the pipe is pressed against an elastic body to prevent the molten resin from overflowing into the pipe. However, if the elastic body deforms radially inward due to the pressure of the molten resin during joining, it is difficult to completely prevent the molten resin from overflowing into the pipe, and there is a possibility that the molten resin may enter the pipe. Furthermore, when joining two synthetic resin pipes by butt joint, before joining, the elastic body inserted from the end opposite the joining end in the axial direction must be moved to the butt joint, and after joining, it must be removed. Moreover, if the molten joining is repeated multiple times, these operations must be repeated multiple times. For this reason, the work efficiency when joining resin pipes by molten joint may not be good.
[0007] Furthermore, when melt-joining resin pipes where the distance between the joining end and the opposite end in the axial direction is long, it may be difficult to move the elastic body to the butt joint.
[0008] Therefore, there is a need for a resin pipe joining structure that allows for easier fusion joining of a pair of resin pipes and prevents a portion of the fused joint from protruding into the joined resin pipe.
[0009] The object of the present invention is to provide a resin pipe joining structure that can more easily prevent a portion of the molten joint from being extruded into a pair of resin pipes. [Means for solving the problem]
[0010] A resin pipe joining structure according to one embodiment of the present invention is a resin pipe joining structure in which the ends of a pair of resin pipes are melt-joined together while butted together in the axial direction. Each of the pair of resin pipes has a molten joint portion at the axial end to be melt-joined, which is melt-joined while butted together in the axial direction. One of the pair of resin pipes has a projection that protrudes in the axial direction so as to be located radially inward from the molten joint portion when the molten joint portions of the pair of resin pipes are butted together in the axial direction (first configuration).
[0011] According to the above configuration, when a pair of resin tubes are butted against each other in the axial direction, the protruding portion can cover the molten joint from the radially inward direction. This prevents a portion of the molten joint from being pushed radially inward into the pair of resin tubes when the pair of resin tubes are brought closer together in the axial direction while the molten joint is molten during molten joining. Therefore, a resin tube joining structure can be provided that more easily prevents a portion of the molten joint from being pushed into the pair of resin tubes.
[0012] In the first configuration described above, the other resin tube of the pair of resin tubes has a accommodating space at the axial end to which the fusion-jointed portions of the pair of resin tubes are abutted together in the axial direction, thereby accommodating the protruding portion (second configuration).
[0013] According to the above configuration, with the fused joints of a pair of resin pipes butted together in the axial direction, a protruding portion that extends axially from one of the resin pipes can be accommodated within a accommodating space provided in the other resin pipe. This accommodating space prevents the protruding portion from interfering with the other resin pipe when the pair of resin pipes are brought closer together in the axial direction during fused joining. Thus, it is possible to fuse the pair of resin pipes together while bringing them closer together in the axial direction.
[0014] In the second configuration described above, the accommodation space extends in the direction of the protruding portion so that it can accommodate a portion of the fused joint that is pushed out from between the ends of the pair of resin pipes when the pair of resin pipes are brought close together, and that has passed through the gap between the protruding portion and the end of the other resin pipe (third configuration).
[0015] According to the above configuration, even if a portion of the molten joint, which is pushed out from between the ends of the pair of resin pipes during molten joining, leaks into the containment space through the gap between the protruding portion and the end of the other resin pipe, the containment space can contain the leaked portion of the molten joint. Therefore, it is possible to prevent a portion of the molten joint from being pushed into the pair of resin pipes.
[0016] In the third configuration described above, the housing space has a volume larger than a portion of the fused joint when the protruding portion is housed therein (fourth configuration).
[0017] As a result, even when the protrusion is housed in the containment space, the containment space can accommodate a portion of the molten joint that has been pushed out from between the ends of the pair of resin pipes and passed through the gap between the protrusion and the end of the other resin pipe. Therefore, it is possible to prevent a portion of the molten joint from being pushed into the pair of resin pipes.
[0018] In the first configuration described above, each of the pair of resin tubes has a resin tube body. The protrusion is located on the radial inner edge of one of the resin tubes and is cylindrical in shape with the same inner diameter as the inner diameter of the resin tube body of the one of the resin tubes (fifth configuration).
[0019] In the above configuration, the projection located on the radial inner edge of one of the resin tubes is cylindrical in shape and has the same inner diameter as the inner diameter of the main body of the resin tube. This prevents the object from getting caught on the projection when passing it through the pair of resin tubes. Therefore, the object can be smoothly inserted into the joined pair of resin tubes.
[0020] In the first configuration described above, the protrusion is located radially inward from the center in the thickness direction of one of the resin tubes (sixth configuration).
[0021] As a result, since the protruding portion is located radially inward of half of the thickness of one resin tube, a fusion joint can be provided in the space radially outward of the protruding portion. Therefore, while the outer sides in the radial direction of the pair of resin tubes are fusion-bonded, the protruding portion can prevent a part of the fusion joint from being extruded radially inward.
[0022] In the first configuration, at least a part of the fusion joint in the pair of resin tubes is located radially outward of the center in the thickness direction of each resin tube (seventh configuration).
[0023] According to the above configuration, while the outer sides in the radial direction of the pair of resin tubes are fusion-bonded, the protruding portion can prevent the molten resin from protruding inward of the pair of resin tubes.
[0024] A resin joint tube in which the pair of resin tubes are joined by the configuration according to any one of the first to seventh (eighth configuration).
[0025] As a result, a resin joint tube in which the pair of resin tubes are joined by a resin tube joint structure capable of preventing a part of the fusion joint from being extruded into the pair of resin tubes can be provided.
[0026] The method for joining resin pipes according to an embodiment of the present invention is a method for joining resin pipes in which the ends of a pair of resin pipes are melt-joined in the axial direction. The method for joining resin pipes forms a melt-joined portion at the axial end portions to be melt-joined in the pair of resin pipes, and forms a protruding portion protruding in the axial direction inward in the radial direction of the melt-joined portion in one of the resin pipes, and forms a housing space portion extending in the axial direction and capable of housing the protruding portion at the axial end portion of the other resin pipe in the resin pipe preparation step; a melting step of heating and melting the melt-joined portions in the pair of resin pipes prepared in the resin pipe preparation step by a heating device; a moving step of relatively moving the pair of resin pipes in a direction approaching each other in the axial direction so that the melt-joined portions melted in the melting step are abutted against each other in the axial direction and the protruding portion is inserted into the housing space portion; and a joining step of cooling the melt-joined portions in a state where the relatively moved pair of resin pipes are joined in the axial direction to join the pair of resin pipes in the axial direction (the first method).
[0027] Thereby, it is possible to provide a method for joining resin pipes that can more easily prevent a part of the melt-joined portion from being extruded into a pair of resin pipes.
Effect of the Invention
[0028] In a pair of resin pipes in the joining structure of resin pipes according to an embodiment of the present invention, each has a melt-joined portion at the axial end portion to be melt-joined. One of the pair of resin pipes has a protruding portion that protrudes inward in the radial direction with respect to the melt-joined portion in a state where the melt-joined portions are abutted against each other.
[0029] Thereby, it is to provide a joining structure of resin pipes that can more easily prevent a part of the melt-joined portion from being extruded into a pair of resin pipes.
Brief Description of the Drawings
[0031] The following describes each embodiment with reference to the drawings. In each drawing, the same parts are denoted by the same reference numerals, and the description of those parts will not be repeated. Note that the dimensions of the components in each drawing do not faithfully represent the dimensions of the actual components or the dimensional ratios of each component.
[0032] In the following explanation, the direction in which the axis P of the resin pipe 10 extends is referred to as the axial direction, the direction perpendicular to the axial direction is referred to as the radial direction, and the direction along the arc centered on the axis P is referred to as the circumferential direction. When a pair of resin pipes 10 and 20 are butted together in the axial direction, the axis P of resin pipe 10 and the axis of resin pipe 20 coincide.
[0033] Furthermore, in the following explanation, the expressions "fix," "connect," and "attach" (hereinafter referred to as "fixing, etc.") include not only cases where components are directly fixed to each other, but also cases where they are fixed to each other via other components. In other words, in the following explanation, the expressions "fixing, etc." include both direct and indirect fixing of components to each other.
[0034] (Overall structure) Referring to Figures 1 to 4, the general configuration of the joining structure 1 for the resin pipes 10 and 20 according to this embodiment will be described. Figure 1 is a top view showing the general configuration of the joining structure 1 for the resin pipes 10 and 20. Figure 2 is a cross-sectional view showing the joining structure 1 for the resin pipes 10 and 20 in the section taken along line II-II in Figure 1. Figure 3 is a partially enlarged view of the area enclosed by the dashed line in Figure 2. Figure 4 is a diagram showing the state from Figure 3 with the second resin pipe 20 removed in order to explain the housing space 14.
[0035] As shown in Figure 1, the joining structure 1 of the resin pipes 10 and 20 is a joining structure of the resin pipes 10 and 20 in a state where the pair of resin pipes 10 and 20 that are to be melt-joined are butted against each other in the axial direction.
[0036] (A pair of resin tubes) The pair of resin tubes 10 and 20 are each cylindrical tubes extending in the axial direction. The pair of resin tubes 10 and 20 are aligned with each other in the axial direction.
[0037] The resin jointed pipe 100, formed by joining a pair of resin pipes 10 and 20, will be described later, but the resin jointed pipe 100 can, for example, have cables (not shown) inserted inside or through which fluids can flow.
[0038] Each of the pair of resin tubes 10 and 20 is made of a thermoplastic resin, such as polyethylene. The pair of resin tubes may also be made of other thermoplastic resins.
[0039] The pair of resin pipes 10, 20 includes a first resin pipe 10 which is located in one axial direction and a second resin pipe 20 which is located in the other axial direction.
[0040] The first resin pipe 10 and the second resin pipe 20 each have a resin pipe body portion 10a, 20a, one end portion 10b, 20b including one axial end, and the other end portion 10c, 20c including the other axial end. Each resin pipe body portion 10a, 20a is located between the one end portion 10b, 20b and the other end portion 10c, 20c in the axial direction.
[0041] The inner diameter and outer diameter of the main body portions 10a, 20a, one end portion 10b, 20b, and the other end portion 10c, 20c of each resin pipe 10, 20 are equivalent.
[0042] The first resin pipe 10 and the second resin pipe 20 have the same configuration. The resin pipe body portions 10a and 20a of each resin pipe 10 and 20 function as insertion passages or flow paths for objects. One end 10b and 20b and the other end 10c and 20c of each resin pipe 10 and 20 are used for joining with other pipes. In the joining structure 1 of the resin pipes 10 and 20, the other end 10c of the first resin pipe 10 and the one end 20b of the second resin pipe 20 are joined.
[0043] Specifically, the first resin pipe 10 has a first one-side fused joint 11 and a first protrusion 13 at one end 10b. The first resin pipe 10 has a first other-side fused joint 12 and a first housing space 14 at the other end 10c.
[0044] Similarly, the second resin pipe 20 has a second one-side fused joint 21 and a second protrusion 23 at one end 20b. The second resin pipe 20 has a second other-side fused joint 22 and a second housing space 24 at the other end 20c.
[0045] The following describes the joining structure 1 between the other end 10c of the first resin pipe 10 and the one end 20b of the second resin pipe 20.
[0046] (joint structure) As shown in Figures 1 to 3, the joining structure 1 of the resin pipes 10 and 20 is such that, before they are joined together, the other end 10c of the first resin pipe 10 and the one end 20b of the second resin pipe 20 are butted together in the axial direction.
[0047] The joining structure 1 of the resin pipes 10 and 20 includes a second one-side fused joint portion 21 and a second protruding portion 23 in the second resin pipe 20, and a first other-side fused joint portion 12 and a first housing space portion 14 in the first resin pipe 10.
[0048] As will be described in more detail later, at one end 20b of the second resin pipe 20, the second one-side fused joint 21 is located radially outward at the one end 20b and at one end in the axial direction, and the second projection 23 is located radially inward relative to the second one-side fused joint 21 and protrudes axially in one direction from the axial end face of the second one-side fused joint 21. Furthermore, at the other end 10c of the first resin pipe 10, the first other-side fused joint 12 is located radially outward at the other end 10c and at the other end in the axial direction, and the first housing space 14 is located radially inward relative to the first other-side fused joint 12 and extends axially.
[0049] In the joining structure 1 of the resin pipes 10 and 20, the first other-side fused joint 12 of the first resin pipe 10 and the second one-side fused joint 21 of the second resin pipe 20 are abutted together in the axial direction, and a part of the second protrusion 23 of the second resin pipe is inserted into the first housing space 14 of the first resin pipe 10.
[0050] The second resin pipe 20 corresponds to one of the resin pipes in the present invention, and the first resin pipe 10 corresponds to the other resin pipe in the present invention. The first other-side fused joint 12 and the second one-side fused joint 21 correspond to the fused joint in the present invention. The second protrusion 23 corresponds to the protrusion in the present invention. The first housing space 14 corresponds to the housing space in the present invention.
[0051] In the following, the first other-side fused joint 12 will be simply referred to as the other-side fused joint 12. The second one-side fused joint 21 will be simply referred to as the one-side fused joint 21. When it is not necessary to explain the other-side fused joint 12 and the one-side fused joint 21 separately, they may be referred to as fused joints 12 and 21. Also, the second protrusion 23 will be simply referred to as the protrusion 23. Also, the first accommodating space 14 will be simply referred to as the accommodating space 14.
[0052] (Fused joint) The other-side fused joint 12 and the one-side fused joint 21 are, respectively, parts of the resin pipes 10 and 20 that are melted by heating with the heating device M, which will be described later in the resin pipe joining method. The extent of the other-side fused joint 12 and the one-side fused joint 21 can be arbitrarily determined by the conditions under which the heating device M is pressed.
[0053] As shown in Figures 2 and 3, the other-side fused joint 12 constitutes a part of the other axial end face of the first resin pipe 10 and a part of the outer circumferential surface of the first resin pipe 10. The other-side fused joint 12 is located at the radially outer end including the outer circumferential surface of the first resin pipe 10 and at the other axial end including the end face, and has a cylindrical shape extending in the circumferential direction. Similarly, the one-side fused joint 21 constitutes a part of one axial end face of the second resin pipe 20 and a part of the outer circumferential surface of the second resin pipe 20. The one-side fused joint 21 is located at the radially outer end including the outer circumferential surface of the second resin pipe 20 and at the axial end including the end face, and has a cylindrical shape extending in the circumferential direction. In other words, the other-side fused joint 12 and the one-side fused joint 21 are located within a predetermined range radially inward from the radial outer edge of each resin pipe 10, 20. Furthermore, as shown in Figure 3, at least a portion of the other-side fused joint 12 and the one-side fused joint 21 are located radially outward from the thickness-direction centerline C of each resin pipe 10 and 20. Note that the thickness-direction centerline of the first resin pipe 10 and the thickness-direction centerline of the second resin pipe 20 coincide.
[0054] The other-side molten joint 12 and the one-side molten joint 21 are aligned axially in a butted state in the joining structure 1 of the resin pipes 10 and 20. As will be described in detail later, as shown by the white arrows in Figure 2, the first resin pipe 10 and the second resin pipe 20 are molten-joined by moving the molten other-side molten joint 12 and the one-side molten joint 21, which are butted axially, closer together.
[0055] (protrusion) As shown in Figures 2 and 3, the projection 23 extends from a position radially inward from the one-sided fused joint 21 toward one axial direction. The projection 23 protrudes axially toward one direction from the axial end face of the one-sided fused joint 21. In other words, the one-sided fused joint 21 is located in a position that radially overlaps with the projection 23. Specifically, the projection 23 constitutes a part of the axial end face of the second resin pipe 20 and a part of the inner circumferential surface of the second resin pipe 20. The projection 23 is located at the radially inward end of the second resin pipe 20, including the inner circumferential surface, and is at the axial end, and has a cylindrical shape that extends in the circumferential direction. In other words, the projection 23 is located within a predetermined range radially outward from the radially inner edge of the second resin pipe 20.
[0056] When the other fused joint 12 and the one fused joint 21 are butted together in the axial direction, a portion of the one axial side of the protruding portion 23 is housed within the housing space 14 of the first resin pipe 10, which will be described later. When the other fused joint 12 and the one fused joint 21 are butted together in the axial direction, the protruding portion 23 is located radially inward relative to the other fused joint 12 and the one fused joint 21. At this time, the other fused joint 12 and the one fused joint 21 are located in a position that overlaps radially with the protruding portion 23. Therefore, the protruding portion 23 covers the other fused joint 12 from the radial inward direction and also covers the joint surface between the other fused joint 12 and the one fused joint 21 from the radial inward direction. Furthermore, as shown in Figure 3, the axial length L23 of the protruding portion 23 is longer than the total length L1221 of the fused joints 12 and 21, which is the sum of the length L21 of the fused joint 21 on one side and the length L12 of the fused joint 12 on the other side, when the fused joint 12 on the other side and the fused joint 21 on one side are butted together in the axial direction.
[0057] As shown in Figure 3, the protrusion 23 is located radially inward from the center line C in the thickness direction. In other words, the other side fused joint 12 and the one side fused joint 21 are located radially outward from such a protrusion 23 and extend radially from the outer surface beyond the center line C in the thickness direction.
[0058] Furthermore, one axial tip of the protruding portion 23 overlaps radially with the portion of the other end 10c of the first resin pipe 10 other than the other fused joint 12, when the other fused joint 12 and the one fused joint 21 are abutted in the axial direction.
[0059] Furthermore, the inner diameter of the protruding portion 23 is equal to the inner diameter of each resin pipe 10, 20. In other words, as shown in Figure 2, the inner diameter R23 of the protruding portion 23 is the same as the inner diameter R20a of the resin pipe body portion 20a of the second resin pipe 20 and the inner diameter R20b of the one end portion 20b. Also, the inner diameter R23 of the protruding portion 23 is the same as the inner diameter R10a of the resin pipe body portion 10a of the first resin pipe 10 and the inner diameter R10c of the other end portion 10c when the other fused joint portion 12 and the one fused joint portion 21 are butted together in the axial direction.
[0060] (Accommodation space) As shown in Figures 2 to 4, the housing space 14 is a cylindrical space extending in the circumferential direction, formed by cutting out the inner circumference portion located at the other axial end of the first resin pipe 10 radially outward. Therefore, the inner diameter of the portion of the other end 10c where the housing space 14 is formed is larger than the inner diameter of the portion of the other end 10c where the housing space 14 is not formed.
[0061] The accommodating space 14 extends in the axial direction in which the protruding portion 23 protrudes, so as to accommodate the protruding portion 23 when the other side fused joint 12 and the one side fused joint 21 are abutted together in the axial direction. If the direction in which the protruding portion protrudes is other than the axial direction, the accommodating space may extend in the direction of the protrusion.
[0062] Specifically, as shown in Figure 3, the axial length L14 of the accommodating space 14 is greater than the sum of the axial length L23 of the protruding portion 23 and the axial length L12 of the other molten joint portion 12. As a result, even when the other molten joint portion 12 and the one molten joint portion 21 are moved closer together, the protruding portion 23 can be accommodated within the accommodating space 14.
[0063] Furthermore, the thickness T14 of the containment space 14 is slightly greater than the thickness T23 of the protrusion 23. As a result, a gap Z of radial distance DZ is formed between the protrusion 23 located within the containment space 14 and the other end 10c of the first resin pipe 10. As will be described in more detail later, when the molten other-side molten joint 12 and the one-side molten joint 21 are moved closer together, a portion of the other-side molten joint 12 and the one-side molten joint 21 may leak into the containment space 14 through the gap Z.
[0064] More specifically, as shown in Figures 3 and 4, the storage space 14 has a storage space 141 before movement and a storage space 142 after movement.
[0065] The pre-movement storage space 141 is a space for accommodating the protruding portion 23 when the other fused joint portion 12 of the first resin pipe 10, which is to be melt-joined, and the one fused joint portion 21 of the second resin pipe 20 are butted together.
[0066] The axial length L141 of the pre-movement storage space 141 is equal to the length obtained by subtracting the axial length L21 of the one-side fused joint 21 from the axial length L23 of the protruding portion 23, when the other-side fused joint 12 and the one-side fused joint 21 are butted together.
[0067] The post-movement containment space 142 is a space that contains the moved protrusion 23 when the first resin pipe 10 and the second resin pipe 20 are moved toward each other after the other side molten joint 12 and the one side molten joint 21 have been melted using the heating device M described later, and also contains a portion of the molten other side molten joint 12 and the one side molten joint 21 that has leaked out through the gap Z.
[0068] The axial length L142 of the relocated storage space 142 is longer than the total length L1221 of the molten joints 12 and 21, which is the sum of the axial length L12 of the other molten joint 12 and the axial length L21 of the one molten joint 21, when the other molten joint 12 and the one molten joint 21 that are to be molten joined are brought together.
[0069] As a result, even when the first resin pipe 10 and the second resin pipe 20 are moved closer together after the other side molten joint 12 and the one side molten joint 21 have been melted using the heating device M, the protruding portion 23 can be prevented from colliding with the first resin pipe 10 in the axial direction. Therefore, the molten other side molten joint 12 and the one side molten joint 21 can be joined more reliably in the axial direction. In addition, a space can be secured to accommodate a portion of the molten other side molten joint 12 and the one side molten joint 21 that has leaked through the gap Z.
[0070] Furthermore, the volume of the relocated storage space 142 is greater than a portion of the total volume of the molten joints 12 and 21, which is the sum of the volume of the other side molten joint 12 and the volume of the one side molten joint 21. More specifically, the volume of the relocated storage space 142 is greater than the volume obtained by subtracting the volume of the portion of the molten joints 12 and 21 used to join the respective resin pipes 10 and 20 from the total volume of the molten joints 12 and 21. Here, the portion of the molten joints 12 and 21 used to join the respective resin pipes 10 and 20 includes the portion of the joint 190 that protrudes outside the resin joint pipe 100, which solidified integrally after the molten joints 12 and 21 were melted in the resin joint pipe 100 into which the respective resin pipes 10 and 20 were molten, and the portion that joins the respective joint pipes 110 and 120 axially at the position where the molten joints 12 and 21 were located before molten joining.
[0071] As a result, when the pair of resin pipes 10 and 20 are moved closer together in order to perform melt joining, the post-movement containment space 142 can catch a portion of the molten joint portion 12 on the other side and the molten joint portion 21 on the one side that would otherwise enter the pair of resin pipes 10 and 20 through the gap Z.
[0072] The molten joint portion 12 on the other side and the molten joint portion 21 on the one side are cooled and solidified after joining to form the joint portion 190. In this way, a resin jointed pipe 100 is formed by the molten joining of a pair of resin pipes.
[0073] (Resin joint pipe) The schematic configuration of the resin joint pipe 100 will be described with reference to Figures 5 and 6. Figure 5 is a top view showing the schematic configuration of the resin joint pipe 100. Figure 6 is a cross-sectional view of the resin joint pipe 100 along the line VI-VI in Figure 5. In Figures 5 and 6, the same reference numerals are used for parts identical to the joint structure 1 of the resin pipes 10 and 20 in Figures 1 to 3, and the description of these identical parts will not be repeated.
[0074] As shown in Figures 5 and 6, the resin joint pipe 100 has a first joint pipe 110, a second joint pipe 120, and a joint portion 190.
[0075] The first connecting pipe 110 and the second connecting pipe 120 are parts of the resin connecting pipe 100 after the first resin pipe 10 and the second resin pipe 20 of the resin pipe 10, 20 joining structure 1 in Figures 1 to 3 are joined by the connecting portion 190.
[0076] The joint 190 is formed integrally after the other-side molten joint 12 and the one-side molten joint 21 in Figures 1 to 3 have been melted and joined together.
[0077] The joint 190 is located between the first connecting pipe 110 and the second connecting pipe 120 in the axial direction, and connects the first connecting pipe 110 and the second connecting pipe 120. The joint 190 is cylindrical.
[0078] The first connecting pipe 110 has a housing space 114 at its other axial end. The second connecting pipe 120 has a projection 123 at one axial end. The housing space 114 corresponds to the housing space 14 before joining. The projection 123 corresponds to the projection 23 before joining. The projection 123 is housed within the housing space 114.
[0079] As shown in Figure 6, a portion of the joint 190 is located in the radial and axial gap between the protruding portion 123 and the other end 110c of the first connecting pipe 110 within the housing space 114. The positioning of a portion of the joint 190 within this gap increases the joint strength of the first connecting pipe 110 and the second connecting pipe 120. The joint 190 does not protrude radially inward beyond the inner surface 100Sa of the resin connecting pipe 100. On the other hand, a portion of the joint 190 leaks radially outward from the outer surface 100Sb of the first connecting pipe 110 and the second connecting pipe 120.
[0080] The resin pipe joining structure 1 of the present embodiment described above is a resin pipe joining structure 1 of which the ends 10c and 20b of a pair of resin pipes 10 and 20 are melt-joined while butted together in the axial direction. Each of the pair of resin pipes 10 and 20 has melt-joined portions 12 and 21 at the axial ends 10c and 20b that are melt-joined while butted together in the axial direction. The second resin pipe 20, which is one of the pair of resin pipes 10 and 20, has a projection 23 that protrudes in the axial direction so as to be located radially inward from the melt-joined portions 12 and 21 when the melt-joined portions 12 and 21 of the pair of resin pipes 10 and 20 are butted together in the axial direction.
[0081] More specifically, the second resin pipe 20, which is one of the pair of resin pipes 10, 20, has a one-sided fused joint 21, which is one of the fused joints 12, 21. The first resin pipe 10, which is the other of the pair of resin pipes 10, 20, has a other-sided fused joint 12, which is the other of the fused joints 12, 21. The second resin pipe 20 has a projection 23 that protrudes axially so as to be located radially inward relative to the other-sided fused joint 12 and the one-sided fused joint 21 when the other-sided fused joint 12 and the one-sided fused joint 21 are abutted together in the axial direction.
[0082] According to the above configuration, when the pair of resin tubes 10 and 20 are butted against each other in the axial direction, that is, when the other fused joint portion 12 and the one fused joint portion 21 are butted against each other in the axial direction, the protruding portion 23 can cover the other fused joint portion 12 and the one fused joint portion 21, which are the fused joint portions 12 and 21, from the radially inward direction.
[0083] This prevents the protrusion 23 from pushing a portion of the other fused joint 12 and the one fused joint 21 radially inward of the pair of resin pipes 10 and 20 when the pair of resin pipes 10 and 20 are brought closer together axially while the other fused joint 12 and the one fused joint 21 are molten during melt joining.
[0084] Therefore, it is possible to provide a joining structure 1 for resin pipes 10 and 20 that can more easily prevent the other side fused joint 12 and a part of the one side fused joint 21 from being pushed out into the pair of resin pipes 10 and 20.
[0085] Furthermore, since a portion of the other-side fused joint 12 and the one-side fused joint 21 is prevented from being pushed radially inward into the pair of resin pipes 10 and 20, it is possible to prevent the object to be inserted into the pipe from getting caught on a portion of the other-side fused joint 12 and the one-side fused joint 21. Similarly, it is possible to prevent resistance from being created in the fluid flowing through the pipe. In addition, since the object does not come into contact with the joint structure 1, unexpected damage to the joint structure 1 can be suppressed, and the lifespan of the joint structure 1 can be extended.
[0086] Furthermore, one axial side of the protrusion 23 overlaps radially with the portion of the other end 10c of the first resin pipe 10 other than the other fused joint 12, when the other fused joint 12 and the one fused joint 21 are abutted in the axial direction. This further suppresses the pushing of a portion of the other fused joint 12 and the one fused joint 21 into the pair of resin pipes 10 and 20 during joining.
[0087] Furthermore, in this embodiment, the first resin pipe 10, which is the other resin pipe of the pair of resin pipes 10, 20, has a accommodating space 14 at the other axial end 10c that is melt-jointed, in which the other fused joint portion 12 and the one fused joint portion 21 of the pair of resin pipes 10, 20 are abutted together in the axial direction, and the protruding portion 23 is accommodated.
[0088] According to the above configuration, with the other side fused joint 12 and the one side fused joint 21 of the pair of resin pipes 10 and 20 butted together in the axial direction, the protruding portion 23 that protrudes in the axial direction from the second resin pipe 20, which is one of the resin pipes 10 and 20, can be accommodated in the housing space 14 provided in the first resin pipe 10, which is the other resin pipe of the pair of resin pipes 10 and 20.
[0089] As a result, the containment space 14 prevents the protruding portion 23 from interfering with the other resin pipe, the first resin pipe 10, when the pair of resin pipes 10 and 20 are brought closer together in the axial direction during melt joining.
[0090] Therefore, it is possible to bring a pair of resin pipes 10 and 20 closer together in the axial direction and fuse them together.
[0091] Furthermore, in this embodiment, the accommodation space 14 extends in the axial direction in which the protruding portion 23 protrudes, so that it can accommodate a portion of the fused joint portion 12, 21 that is pushed out from between the ends 10c, 20b of the pair of resin pipes 10, 20 when the pair of resin pipes 10, 20 are brought close together, and that has passed through the gap Z between the protruding portion 23 and the end 10c of the first resin pipe 10.
[0092] According to the above configuration, even if, during fusion joining, a portion of the other-side fused joint 12 and one-side fused joint 21 that is pushed out from between the ends 10c and 20b of the pair of resin pipes 10 and 20 leaks into the containment space 14 through the gap Z between the protruding portion 23 and the end 10c of the first resin pipe 10, the containment space 14 can accommodate the leaked portion of the other-side fused joint 12 and one-side fused joint 21.
[0093] Therefore, it is possible to prevent a portion of the other-side fused joint 12 and the one-side fused joint 21 from being pushed into the pair of resin pipes 10 and 20.
[0094] Furthermore, in this embodiment, the housing space 14 has a volume larger than the volume of the other side fused joint 12 and a portion of the one side fused joint 21 when the protruding portion 23 is housed therein.
[0095] More specifically, the volume of the relocated storage space 142 is greater than a portion of the total volume obtained by adding the volume of the other side fused joint 12 and the volume of the one side fused joint 21.
[0096] As a result, even when the protrusion 23 is housed in the housing space 14, the housing space 14 can accommodate the other-side fused joint 12 and a portion of the one-side fused joint 21 that are pushed out from between the ends 10c and 20b of the pair of resin pipes 10 and 20 and pass through the gap Z between the protrusion 23 and the end 10c of the first resin pipe 10.
[0097] Therefore, it is possible to prevent a portion of the other-side fused joint 12 and the one-side fused joint 21 from being pushed into the pair of resin pipes 10 and 20.
[0098] In this embodiment, the pair of resin pipes 10 and 20 each have resin pipe body portions 10a and 20a. The protruding portion 23 is located on the radial inner edge of the second resin pipe 20, which is one of the resin pipes, and is cylindrical in shape with the same inner diameter R23 as the inner diameter R20a of the resin pipe body portion 20a of the second resin pipe 20.
[0099] In the above configuration, the projection 23 located on the radial inner edge of the second resin pipe 20 is cylindrical in shape and has the same inner diameter R23 as the inner diameter R20a of the resin pipe body portion 20a of the second resin pipe 20.
[0100] This prevents objects such as cables or fluids from getting caught on the protruding portion 23 when passing them through the other end 20c of the second resin pipe 20.
[0101] Furthermore, the inner diameter R23 of the protruding portion 23 is equal to the inner diameter R10a of the resin pipe body portion 10a of the first resin pipe 10, and is also equal to the inner diameter R10c of the other end portion 10c.
[0102] This prevents the object from getting caught on the protruding portion 23 even when passing the object through the resin jointed pipe 100, which is formed by melt-joining a pair of resin pipes 10 and 20. Therefore, the object can be smoothly inserted into the resin jointed pipe 100. Furthermore, when a fluid is flowed through the resin jointed pipe 100, the protruding portion 23 can be prevented from becoming a resistance to the fluid. In addition, damage to at least one of the object and the protruding portion 23 by the object or the fluid can be prevented.
[0103] Furthermore, in this embodiment, the protrusion 23 is located radially inward from the center line C in the thickness direction, which is located in the center of the thickness direction of the second resin pipe 20, which is one of the resin pipes.
[0104] As a result, the protruding portion 23 is located radially inward from half the thickness of the second resin pipe 20, allowing the other side fused joint 12 and the one side fused joint 21 to be provided radially outward from the protruding portion 23.
[0105] Therefore, while melt-joining the radially outer portions of the pair of resin tubes 10 and 20 beyond the protruding portions 23, it is possible to prevent the other melt-joint portion 12 and a portion of the one melt-joint portion 21 from being pushed radially inward by the protruding portions 23.
[0106] Furthermore, in this embodiment, at least a portion of the other-side fused joint 12 and the one-side fused joint 21 of the pair of resin pipes 10 and 20 are located radially outward from the thickness-direction center line C, which is located in the thickness-direction center of each resin pipe 10 and 20.
[0107] According to the above configuration, the radial outer surfaces of the pair of resin tubes 10 and 20 are melt-joined together, while the protrusion 23 prevents the molten resin from spilling out into the pair of resin tubes 10 and 20.
[0108] In this embodiment, the resin jointed pipe 100 is formed by joining a pair of resin pipes 10 and 20.
[0109] This makes it possible to provide a resin jointed pipe 100 in which a pair of resin pipes 10, 20 are joined by a joining structure 1 that prevents a portion of the other side fused joint 12 and a portion of the one side fused joint 21 from being pushed out into the pair of resin pipes 10, 20.
[0110] (Method of joining resin pipes) Next, the method for joining the resin pipes 10 and 20 will be described. Figure 7 is a flowchart showing the method for joining the resin pipes 10 and 20. Figure 8 shows the formation of a one-sided fused joint 21 and a protruding portion 23 on the second resin pipe 20, and the formation of a other-sided fused joint 12 and a housing space 14 on the first resin pipe 10. Figure 9 shows the other-sided fused joint 12 and the one-sided fused joint 21 being brought into contact with the heating device M. Figure 10 shows the heating device M being removed and the other-sided fused joint 12 and the one-sided fused joint 21 being butted together in the axial direction.
[0111] In step S1 of the flowchart shown in Figure 7, the first resin pipe 10 and the second resin pipe 20 are prepared.
[0112] Next, in step S2 of the flowchart shown in Figure 7, as shown in Figure 8, the radially outer portion H2 of one end 20b of the prepared second resin pipe 20 is cut out in a cylindrical shape, and one end on the radially outer side of the one end 20b is made into a one-side molten joint 21 which is to be melted using the heating device M, and a projection 23 that protrudes in the axial direction is formed radially inward of the one-side molten joint 21.
[0113] Next, in step S3 of the flowchart shown in Figure 7, as shown in Figure 8, the radially inner portion H1 of the first resin pipe 10 is cut out in a cylindrical shape, and the radially outer end of the other end 10c, in the axial direction, is made to abut with the one-side fused joint portion 21 of the second resin pipe 20 to form the other-side fused joint portion 12. At the same time, a accommodating space portion 14 is formed radially inward of the other-side fused joint portion 12 to accommodate the protruding portion 23 when the other-side fused joint portion 12 is abutted with the one-side fused joint portion 21.
[0114] Next, in step S4 of the flowchart shown in Figure 7, the heating section M1 of the heating device M shown in Figure 9 is heated to a temperature at which the other-side fused joint 12 and the one-side fused joint 21 can be melted. The heating device M is a device having a heatable cylindrical heating section M1. The heating device M can melt the other-side fused joint 12 and the one-side fused joint 21 formed on the ends 10c and 20b of each resin tube 10 and 20, which are made of thermoplastic resin, by bringing the heated heating section M1 into contact with them. The heating device can adopt the configuration of a known device. The heating device may include, for example, a metal heating section having an openable and closable cylindrical structure and a heat source capable of heating the heating section.
[0115] Next, as shown in Figure 9, the heating section M1 is sandwiched axially between the resin tubes 10 and 20, bringing the other molten joint 12 and the one molten joint 21 into contact with the heated heating section M1. This causes the other molten joint 12 and the one molten joint 21 to be in a molten state.
[0116] Next, in step S5 of the flowchart shown in Figure 7, as shown in Figure 10, after removing the heating section M1 of the heating device M, the molten other-side molten joint 12 and the one-side molten joint 21 are brought together in the axial direction. In this state, a portion of the axial side of the protrusion 23 is located within the housing space 14. Subsequently, the pair of resin pipes 10 and 20 are moved relative to each other in the axial direction so that the protrusion 23 of the second resin pipe 20 is inserted into the housing space 14 of the first resin pipe 10. At this time, the molten other-side molten joint 12 and the one-side molten joint 21 become one with each other and are pushed out from between the first resin pipe 10 and the second resin pipe 20 in the axial direction.
[0117] In this way, the molten other-side molten joint 12 and one-side molten joint 21, which are extruded from between the first resin pipe 10 and the second resin pipe 20 in the axial direction, are prevented from leaking into the pair of resin pipes 10 and 20 by the protruding portion 23.
[0118] More specifically, a portion of the molten other-side molten joint 12 and one-side molten joint 21 leaks into the containment space 14 by passing through the radial gap Z between the protruding portion 23 and the other-side end 10c of the first resin pipe 10. However, during molten joining, the radial inward movement of the molten other-side molten joint 12 and one-side molten joint 21 is hindered by the protruding portion 23. As a result, the amount that moves outside the pair of resin pipes 10 and 20 increases, while the amount that leaks into the containment space 14 by passing through the gap Z decreases. This prevents a portion of the molten other-side molten joint 12 and one-side molten joint 21 that has passed through the gap Z from overflowing from the containment space 14 into the pair of resin pipes 10 and 20.
[0119] In this case, a portion of the molten fused joint 12 on the other side and the fused joint 21 on the one side leaks radially outward from the outer surface of the pair of resin pipes 10 and 20.
[0120] Next, in step S6 of the flowchart shown in Figure 7, the other molten joint 12 and the one molten joint 21, which are one unit in a molten state, cool and solidify. This melts and joins the pair of resin tubes 10 and 20 in the axial direction to form the resin joint tube 100.
[0121] After that, the flow shown in Figure 7 is terminated (END).
[0122] Here, steps S1-S3 correspond to the resin pipe preparation process, step S4 corresponds to the melting process, step S5 corresponds to the transfer process, and step S6 corresponds to the joining process.
[0123] A resin pipe joining method according to one embodiment of the present invention is a resin pipe joining method in which the ends 10c and 20b of a pair of resin pipes 10 and 20 are fused together in the axial direction. The resin pipe joining method is a resin pipe preparation step S1-S3 in which a fused joint portion 12 on the other side and a fused joint portion 21 on the axial ends 10c and 20b of a pair of resin pipes 10 and 20 that are to be fused together are formed, and a protruding portion 23 that protrudes in the axial direction is formed radially inward of the fused joint portion 21 on the second resin pipe 20, which is one of the resin pipes, and a housing space portion 14 that extends in the axial direction and can accommodate the protruding portion 23 is formed on the axial end 10c of the first resin pipe 10, which is the other resin pipe, and the fused joint portion on the other side of the pair of resin pipes 10 and 20 prepared in the resin pipe preparation step S1-S3 The process includes: a melting step S4 in which the 12 and the one-side fused joint 21 are heated and melted by the heating section M1 of the heating device M; a moving step S5 in which the pair of resin pipes 10 and 20 are relatively moved in a direction that brings them closer to each other in the axial direction so that the other-side fused joint 12 and the one-side fused joint 21 that were melted in the melting step S4 are abutted together in the axial direction and the protruding portion 23 is inserted into the housing space 14; and a joining step S6 in which the pair of resin pipes 10 and 20 that have been moved relative to each other are abutted together in the axial direction, and the other-side fused joint 12 and the one-side fused joint 21 are cooled to join the pair of resin pipes 10 and 20 in the axial direction.
[0124] This provides a method for joining resin pipes 10 and 20 that makes it easier to prevent the other side fused joint 12 and a portion of the one side fused joint 21 from being pushed out into the pair of resin pipes 10 and 20.
[0125] (Other embodiments) Although embodiments of the present invention have been described above, the embodiments described above are merely examples for carrying out the present invention. Therefore, the invention is not limited to the embodiments described above, and it is possible to carry out the invention by appropriately modifying the embodiments described above without departing from the spirit of the invention.
[0126] In the above embodiment, the joining structure 1 of the resin pipes 10 and 20 is a joining structure between the other end 10c of the first resin pipe 10 and one end 20b of the second resin pipe 20. However, the other end of a third pipe having the same configuration as the first and second resin pipes may be joined to one end of the first resin pipe. Similarly, the other end of a fourth pipe having the same configuration as the first and second resin pipes may be joined to the other end of the second resin pipe. Multiple resin pipes may be joined axially by multiple joining structures. This allows multiple resin pipes to be extended axially.
[0127] In the above embodiment, the first resin pipe 10 has a first projection 13 at one end 10b and a first housing space 14 at the other end 10c. The second resin pipe 20 has a second projection 23 at one end 20b and a second housing space 24 at the other end 20c. However, the first resin pipe may have a first housing space at one end and a first projection at the other end. The second resin pipe may have a second housing space at one end and a second projection at the other end. In this case, the resin pipe joining structure is such that, with the other fused joint of the first resin pipe and the one fused joint of the second resin pipe butted together in the axial direction, the first projection at the other end of the first resin pipe is housed in the second housing space at one end of the second resin pipe. Furthermore, the first resin pipe may have projections at both ends in the axial direction, and the second resin pipe may have housing spaces at both ends in the axial direction. The first resin tube may have storage spaces at both ends in the axial direction, and the second resin tube may have protrusions at both ends in the axial direction.
[0128] In the above embodiment, the inner diameter and outer diameter of the resin pipe body portions 10a, 20a, one end portion 10b, 20b, and the other end portion 10c, 20c of each resin pipe 10, 20 are the same. However, the inner diameter and outer diameter of the resin pipe body portion of each resin pipe and the inner diameter and outer diameter of the one end portion and the other end portion of each resin pipe may be different.
[0129] In the above embodiment, the other-side fused joint 12, the one-side fused joint 21, the protruding portion 23, and the housing space 14 are each cylindrical in shape. However, the other-side fused joint, the one-side fused joint, the protruding portion, and the housing space may each have any shape as long as they are able to join a pair of resin pipes in the axial direction and are formed at the abutting ends of each resin pipe. For example, the other-side fused joint, the one-side fused joint, the protruding portion, and the housing space may each be formed in an arc shape or columnar shape on a part of the circumferential direction at the abutting axial ends of a pair of resin pipes.
[0130] In the above embodiment, the other-side fused joint 12 and the one-side fused joint 21 are formed on the radial outer edge of each resin pipe 10, 20. However, the other-side fused joint and the one-side fused joint may be formed in locations other than the radial outer edge of each resin pipe. For example, the other-side fused joint and the one-side fused joint may be formed between the outer edge and the inner edge of each resin pipe.
[0131] In the above embodiment, the projection 23 is formed on the radial inner edge of the second resin pipe 20. However, the projection may be formed in a location other than the radial inner edge of the second resin pipe. For example, the projection may be formed between the outer edge and the inner edge of the second resin pipe.
[0132] In the above embodiment, the first resin pipe 10 has a housing space 14. The housing space 14 is formed on the radial inner edge of the first resin pipe 10. However, the first resin pipe does not have to have a housing space. For example, the first resin pipe may have a thickness such that it does not interfere with the protruding portion of the second resin pipe when the other side fused joint and the one side fused joint are abutted in the axial direction. The housing space may be formed in a location other than the radial inner edge of the first resin pipe.
[0133] In the above embodiment, the thickness T14 of the housing space 14 is slightly greater than the thickness T23 of the protruding portion 23. A gap Z of distance DZ is formed radially between the protruding portion 23 located within the housing space 14 and the other end 10c of the first resin pipe 10. However, the thickness of the housing space may be equal to the thickness of the protruding portion. A gap does not need to be formed radially between the protruding portion located within the housing space and the other end of the first resin pipe.
[0134] In the above embodiment, one axial side of the protrusion 23 overlaps radially with the portion of the other end 10c of the first resin pipe 10 other than the other fused joint 12, when the other fused joint 12 and the one fused joint 21 are abutted in the axial direction. However, the protrusion does not need to overlap radially with the portion of the other end of the first resin pipe other than the other fused joint, as long as it is located radially inward of the other fused joint and the one fused joint when the other fused joint and the one fused joint are abutted in the axial direction.
[0135] In the above embodiment, the joint structure 1 has a protruding portion 23. However, the joint structure does not have to have a protruding portion. Figure 11 is a cross-sectional view showing a joint structure 200 of a resin pipe without a protruding portion according to another embodiment. Figure 12 is a cross-sectional view of a resin joint pipe 300 without a protruding portion according to another embodiment. Hereafter, components similar to those in the above embodiment will be denoted by the same reference numerals and their descriptions will be omitted, and only components different from the above embodiment will be described.
[0136] As shown in Figure 11, in the joining structure 200 according to another embodiment, the second resin pipe 220 has only a one-sided fused joint 21 and no protruding portion. Specifically, the joining structure 200 has a one-sided fused joint 21, a other-sided fused joint 12, and a space 214 which is a space including the housing space of the first resin pipe 10.
[0137] The space 214 is cylindrical in shape, such that when the other fused joint 12 and the one fused joint 21 are butted together in the axial direction, a portion of the inner circumferential surface of the first resin pipe 10 and the second resin pipe 220 is cut out radially outward. The space 214 is located radially inward relative to the other fused joint 12 and the one fused joint 21. Specifically, the other axial end of the space 214 is located radially inward relative to the other fused joint 12 and the one fused joint 21. The space may have a shape other than cylindrical. Also, at least a portion of the space other than the other axial end may be located radially inward relative to the other fused joint and the one fused joint. For example, the axial central part of the space may be located radially inward relative to the other fused joint and the one fused joint. In this case, the other end of the first resin pipe and the one end of the second resin pipe may each have a accommodating space.
[0138] As shown in Figures 11 and 12, the space 214 accommodates a portion of the molten joint 12 and 21 that leaks radially inward when the first resin pipe 10 and the second resin pipe 220 are moved closer together after the other molten joint 12 and the 1st molten joint 21 have been melted. In this way, the space 214 can receive (accommodate) a portion of the molten joint 12 and 21 that would otherwise penetrate inward beyond the inner diameter of the pair of resin pipes 10 and 220 when the pair of resin pipes 10 and 220 are moved closer together in order to perform molten joining.
[0139] The molten joint portion 12 on the other side and the molten joint portion 21 on the one side are cooled and solidified after joining to form the joint portion 390. In this way, as shown in Figure 12, a resin jointed pipe 300 is formed by the molten joining of a pair of resin pipes.
[0140] The resin jointed pipe 100 has a first jointed pipe 110, a second jointed pipe 320, and a joint portion 390. The second jointed pipe 320 does not have any protruding portions. The joint portion 390 does not protrude radially inward beyond the inner surface 300Sa of the resin jointed pipe 300.
[0141] According to the other embodiment of the joining structure 200 described above, even if a portion of the other side molten joint 12 and the one side molten joint 21 that are extruded from between the ends of the pair of resin pipes 10,220 during melt joining leaks radially inward, the space 214 can accommodate the leaked portion of the other side molten joint 12 and the one side molten joint 21. Therefore, it is possible to prevent the joint 390, which is formed when the molten other side molten joint 12 and the one side molten joint 21 are cooled and solidified after joining, from protruding radially inward beyond the inner surface 300Sa inside the resin joining pipe 300. [Industrial applicability]
[0142] This invention can be used in a joining structure for a pair of resin pipes in which the ends of a pair of resin pipes are butted together in the axial direction and then fused together. [Explanation of symbols]
[0143] 1,200 joint structure 10,20 Resin pipes 10a, 20a Resin pipe body 10b,20b One end 10c,110c,20c Other end 10. First resin pipe (the other resin pipe) 11. First side fused joint 12. First other side fused joint (fused joint) 13 First protrusion 14. First containment space (containment space) 141 Pre-movement storage space 142 Post-movement storage space 20, 220 Second resin pipe (one of the resin pipes) 21. Second first side fused joint (fused joint) 22 Second other-side fused joint 23 Second protrusion (protrusion) 24. First containment space 100 Resin jointed pipe 100Sa, 300Sa Inner Self 100Sb outer surface 110 1st joint pipe 114 First containment space 120, 320 2nd joint pipe 123 Second protrusion 190, 390 joint 214 Space section C Center line in the thickness direction R10a, R10c, R20a, R20b, R23 Inner diameter M heating device M1 heating section P axis Z gap
Claims
1. A resin pipe joining structure in which the ends of a pair of resin pipes are butted together in the axial direction and then fused together, The pair of resin tubes, each of them, The axial end to be melt-joined has a molten joint portion that is melt-joined in a state where it is butted in the axial direction, One of the pair of resin tubes is With the fused joints of the pair of resin tubes abutted together in the axial direction, the tubes have a projection that protrudes in the axial direction so as to be located radially inward from the fused joint. Joining structure for resin pipes.
2. A resin pipe joining structure according to claim 1, Of the pair of resin pipes, the other resin pipe is The axial end to be fused has a accommodating space capable of accommodating the protruding portion when the fused joint portions of the pair of resin tubes are abutted together in the axial direction. Joining structure for resin pipes.
3. A resin pipe joining structure according to claim 2, The aforementioned accommodation space section is The protruding portion extends in the direction of the protrusion so that it can accommodate a portion of the fused joint that is pushed out from between the ends of the pair of resin pipes when the pair of resin pipes are brought close together and passes through the gap between the protruding portion and the end of the other resin pipe. Joining structure for resin pipes.
4. A resin pipe joining structure according to claim 3, The aforementioned housing space, when the protruding portion is housed, has a volume larger than a portion of the fused joint. Joining structure for resin pipes.
5. A resin pipe joining structure according to claim 1, Each of the pair of resin tubes has a resin tube body, The protruding portion is located on the radial inner edge of the one resin tube and is cylindrical in shape, having the same inner diameter as the inner diameter of the resin tube body of the one resin tube. Joining structure for resin pipes.
6. A resin pipe joining structure according to claim 1, The aforementioned protrusion is located radially inward from the position of the center in the thickness direction of one of the resin tubes. Joining structure for resin pipes.
7. A resin pipe joining structure according to claim 1, At least a portion of the fused joint in the pair of resin tubes is located radially outward from the center in the thickness direction of each resin tube. Joining structure for resin pipes.
8. A resin jointed pipe in which a pair of resin pipes are joined by a resin pipe joining structure according to any one of claims 1 to 7.
9. A method for joining resin pipes, in which the ends of a pair of resin pipes are fused together in the axial direction, A resin pipe preparation step involves forming a fused joint at the axial end of the pair of resin pipes to be fused, forming a projection that protrudes in the axial direction radially inward from the fused joint in one of the resin pipes, and forming a housing space at the axial end of the other resin pipe that extends in the axial direction and can accommodate the projection; A melting step is performed in which the fused joint portion of the pair of resin pipes prepared in the resin pipe preparation step is heated and melted by a heating device, A moving step involves bringing the pair of resin tubes closer together in the axial direction so that the molten joints melted in the melting step are brought together in the axial direction and the protruding portion is inserted into the housing space; A joining step in which the pair of resin tubes, which have been moved relative to each other, are joined together in the axial direction, and the molten joint is cooled to join the pair of resin tubes together in the axial direction, Having, Method for joining resin pipes.