JP2007154997A - Joint tube and joining method of cylindrical member using this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joint tube and a joining method of a cylindrical member capable of preventing leakage of a pressure medium even if pressure of the pressure medium flowing in the connected cylindrical member becomes high. <P>SOLUTION: The joint tube 1 of a shape-memory alloy for joining end parts of the cylindrical members C which face against each other. The joint tube 1 is provided with cylindrical insertion parts 2 at both end sides having an outer diameter D shorter than an inner diameter D of the cylindrical member C. The cylindrical insertion part 2 recovers its shape by heating it while inserted in a hollow part Ca of the cylindrical member C and then an outer diameter d becomes larger than the inner diameter D of the cylindrical member C. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

    The present invention relates to a joint pipe made of a shape memory alloy used for joining cylindrical members together.

Conventionally, when using a joint pipe made of a shape memory alloy as described above and joining the ends of the cylindrical members facing each other, for example, the hollow part of the joint pipe having an inner diameter larger than the outer diameter of the cylindrical member Then, the ends of the cylindrical member are inserted and faced from both sides, and in this state, the joint pipe is heated to recover its shape so that its inner diameter becomes smaller than the outer diameter of the cylindrical member, thereby the cylindrical member The ends of each other were joined together.
JP 2004-324677 A

  However, in the prior art, when the pressure of the pressure medium flowing through the joined cylindrical members increases, a pressing force in the diameter expansion direction acts on the joint pipe at the abutting portion of the cylindrical members. When the pressure becomes even higher, there is a problem that there is no possibility that the pressure medium leaks due to a gap between the joint pipe and the tubular member. This has been a conventional problem.

  The present invention has been made by paying attention to the conventional problems described above, and is a joint pipe that can prevent the pressure medium from leaking even if the pressure of the pressure medium flowing through the joined cylindrical members increases. And it aims at providing the joining method of the cylindrical member using this.

  The present invention is a joint pipe made of a shape memory alloy for joining together cylindrical members, and includes a tubular insertion portion having an outer diameter smaller than the inner diameter of the cylindrical member. It is characterized in that the shape is recovered by heating in a state where it is inserted into the hollow portion, and the outer diameter becomes larger than the inner diameter of the cylindrical member. As a means to solve the problem.

  When the pressure of the pressure medium flowing through the tubular member joined using the joint pipe of the present invention increases, the pressure medium pushes the joint pipe in the diameter-expanding direction, and the outer peripheral wall of the joint pipe is pressed against the inner peripheral wall of the tubular member. Therefore, the sealing performance of the joined portion of the cylindrical member is improved.

  According to the present invention, since it is configured as described above, it is possible to reliably prevent the pressure medium from leaking from the joined portion of the cylindrical member even if the pressure of the pressure medium flowing through the joined cylindrical member is increased. This is a very good effect that is possible.

  In the joint pipe of the present invention, when used to join the end portions of the cylindrical member facing each other, a tubular insertion portion having an outer diameter smaller than the inner diameter of the cylindrical member is provided at both ends. Further, it is possible to adopt a configuration in which the tubular insertion portion is heated while being inserted into the hollow portion of the tubular member, and the shape is recovered so that the outer diameter becomes larger than the inner diameter of the tubular member.

  Then, when joining the end portions of the tubular members facing each other using the joint pipe adopting this configuration, the tubular insertion portions having an outer diameter smaller than the inner diameter of the tubular member in the joint pipe are both set. After inserting into each hollow part of the cylindrical member, the joint pipe is heated to recover the shape so that the outer diameter of the tubular insertion part is larger than the inner diameter of the cylindrical member, and the ends of the cylindrical member are joined together. .

  On the other hand, in the joint pipe of the present invention, when used to overlap and join the ends of a double cylindrical member formed by coaxially combining cylindrical members having different diameters, A tubular insertion portion having an outer diameter smaller than the inner diameter of the small-diameter cylindrical member is provided, and the tubular insertion portion is heated in a state of being inserted into the hollow portion of the small-diameter cylindrical member to recover the shape and A configuration in which the outer diameter is larger than the inner diameter of the cylindrical member can be employed.

  And, when using the joint pipe adopting this configuration to join the end portions of the double cylindrical member formed by coaxially combining the cylindrical members having different diameters, in the double cylindrical member, After inserting the tubular insertion portion having an outer diameter smaller than the inner diameter of the small-diameter cylindrical member into the hollow portion of the small-diameter cylindrical member, the joint tube is heated to reduce the outer diameter of the tubular insertion portion. The shape is recovered to be larger than the inner diameter, and the ends of the double cylindrical members are overlapped and joined.

  Further, in the joint pipe of the present invention, the pressure of the pressure medium flowing through the cylindrical member is expanded in the direction in which the tubular insertion part expands the diameter of the tubular insertion part that recovers its shape by heating and contacts the inner peripheral wall of the cylindrical member. It can be set as the structure which provided the pressure receiving part made to act intensively as force, and by setting it as this structure, the sealing performance of the junction part of a cylindrical member will improve more.

  Furthermore, in the joint pipe according to the present invention, a protrusion continuously formed in the circumferential direction on the inner peripheral wall of the tubular insertion portion can be used as a pressure receiving portion. With such a structure, the tubular member flows. Since the pressure of the pressure medium acts in the normal direction of the protrusion, the force is concentrated at the center of the protrusion, and the contact force is further increased. As a result, the sealing performance of the joining portion of the cylindrical member is increased. Will be further improved.

  Furthermore, in the joint pipe of the present invention, the projection as the pressure receiving portion has at least one inclined surface that is inclined with respect to the axis of the tubular insertion portion, or the projection as the pressure receiving portion is the tubular insertion portion. The configuration may include at least one inclined surface and a curved surface that are inclined with respect to the axis of the portion, and the protrusion as the pressure receiving portion may be configured of a curved surface.

  If the projection as the pressure receiving portion has at least one inclined surface inclined with respect to the axis of the tubular insertion portion, for example, if it has one inclined surface, the method of one inclined surface Since the pressure of the pressure medium acts in the linear direction, the force is concentrated at the center of the protrusion and the contact force is further increased. As a result, the sealing performance of the joint portion of the cylindrical member is further increased. In this case, if there are two inclined surfaces, the pressure of the pressure medium acts in the normal direction of the two inclined surfaces, so that the force is efficiently concentrated at the center of the protrusion. Thus, the contact force is further increased, and the sealing performance of the joined portion of the tubular member is further improved.

  When the protrusion as the pressure receiving portion has at least one inclined surface and a curved surface, the pressure of the pressure medium acts in the normal direction of the one inclined surface and the normal direction of the curved surface. Since the force is efficiently concentrated at the center of the protrusion, the contact force is further increased, and as a result, the sealing performance of the joining portion of the cylindrical member is further improved.

  Assuming that the protrusion as the pressure receiving portion has a curved surface, the pressure of the pressure medium acts in the normal direction of the curved surface, so that the force is more efficiently concentrated at the center of the protrusion. As a result, the contact force is further increased, and as a result, the sealing performance of the joined portion of the cylindrical member is further improved.

  Furthermore, in the joint pipe of the present invention, it is possible to adopt a configuration in which the tubular insertion portion in the stage before being inserted into the hollow portion of the cylindrical member and heated is tapered. Then, the tubular insertion portion can be easily inserted into the hollow portion of the cylindrical member, and the tapered tubular insertion portion is extremely easy by simply sandwiching the joint pipe with the upper and lower tapered molds. It can be produced.

  Furthermore, in the joint pipe of the present invention, it is possible to adopt a configuration including a positioning portion that determines a predetermined insertion amount of the tubular insertion portion with respect to the hollow portion of the cylindrical member. The predetermined insertion amount of the tubular insertion portion of the joint pipe to be inserted into the hollow portion of the pipe can be determined very easily, that is, the positioning of the tubular insertion portion with respect to the tubular member can be performed very easily, thereby improving productivity. Will be achieved.

  Furthermore, in the joint pipe of the present invention, a configuration is adopted in which outward projections that are continuous in the circumferential direction are provided on the outer peripheral wall of the tubular insertion portion that recovers its shape by heating and contacts the inner peripheral wall of the cylindrical member. In this case, since the inner peripheral wall of the tubular member and the outer peripheral wall of the tubular insertion portion are continuously and more closely attached in the circumferential direction, the contact force between the two is increased. The sealing performance of the part will be further improved.

  Furthermore, in the joint pipe of the present invention, the outward projection can be made softer than the cylindrical member. With such a configuration, the outward projection is positively provided inside the cylindrical member. Since it deforms and adheres more closely following the shape of the peripheral wall, the abutting force of both increases, and the sealing performance of the joined portion of the tubular member is further improved.

  Furthermore, in the joint pipe of the present invention, the outward projection may be provided separately from the tubular insertion portion. With such a configuration, the material of the soft projection can be selected relatively diversely. It becomes.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example.

  FIG. 1 shows an embodiment of the joint pipe of the present invention. In this embodiment, the case of using the joint pipe of the present invention to join cylindrical members through which a pressure medium flows is shown.

  As shown in FIG. 1, the joint pipe 1 is made of a shape memory alloy in which end portions of a cylindrical member C for flowing a pressure medium are opposed to each other, and both end portions of the cylindrical member C are connected to each other. A tubular insertion portion 2 having a taper shape with an outer diameter smaller than the inner diameter is formed, and a step 3 as a positioning portion is provided between the tubular insertion portion 2 and the central portion, thereby forming a taper shape. The tubular insertion portion 2 recovers its shape by being heated while being inserted into the hollow portion Ca of the cylindrical member C, and the outer diameter d is larger than the inner diameter D of the cylindrical member C.

  When manufacturing this joint pipe 1, as shown in FIG. 3A, a cylindrical member 1A made of a shape memory alloy having a step 3 in the central portion is produced. As shown in FIG. In a state where the cylindrical member 1A is set in the holder 12 of the lower die 11 of the taper machining die, the upper insert 13 is tightened to form the tubular insertion portion 2 in a tapered shape as shown in FIG. As described above, when the taper machining dies 11 and 13 are used, the joint pipe 1 having the tapered tubular insertion portion 2 and the step 3 as the positioning portion can be manufactured very easily.

  Next, a procedure for joining the end portions of the cylindrical member C so as to face each other using the joint pipe 1 will be described.

  First, as shown in FIG.1 (b), the tubular insertion part 2 of the joint pipe | tube 1 is each inserted in each hollow part Ca of the cylindrical member C which made the edge parts oppose.

  At this time, since the tubular insertion portions 2 of the joint pipe 1 are all tapered, the insertion of the tubular insertion portion 2 into the hollow portion Ca of the tubular member C is very simple. Thus, since the step 3 located at the center portion of the joint pipe 1 contacts the end surface of the tubular member C, the predetermined insertion amount of the tubular insertion portion 2 can be determined very easily.

  Thereafter, when the joint pipe 1 made of the shape memory alloy is heated by, for example, a coil heating device 15 as shown in FIG. 2A, the joint pipe 1 is memorized as shown in FIG. Since the shape is recovered so that the outer diameter d of the tubular insertion portion 2 is larger than the inner diameter D of the tubular member C, the tubular insertion of the joint pipe 1 on the inner peripheral wall Cb of the tubular member C is achieved. The outer peripheral wall 2a of the portion 2 comes into contact with an extremely high force, whereby the ends of the cylindrical member C are joined to each other.

  In the above-described joint pipe 1, when a pressure medium is passed through the joined cylindrical member C, as shown by the arrow in FIG. 2 (b), pressure acts on the inner peripheral wall 1 a of the joint pipe 1, and the joint pipe 1 is The outer peripheral wall 2a of the tubular insertion portion 2 of the joint pipe 1 that is pushed and expanded in the diameter increasing direction and is in contact with the inner peripheral wall Cb of the cylindrical member C with high force is applied to the inner peripheral wall Cb of the cylindrical member C with higher force. Since the pressure contact is used, the sealing performance is further improved by the pressure of the pressure medium. Therefore, even if the pressure of the pressure medium increases, it is ensured that the pressure medium leaks from the joint portion of the cylindrical member C. It can be blocked.

  FIG. 4 shows another embodiment of the joint pipe of the present invention. In this embodiment, a case where the joint pipe of the present invention is used for an engine double exhaust pipe is shown.

  As shown in FIG. 4, the double exhaust pipe E of the engine is formed by coaxially combining a thin inner cylinder E1 and a thick outer cylinder E2 having different diameters to improve performance. In addition, it is known that it is advantageous to reduce the thickness of the inner cylinder E1.

  The joint pipe 21 made of a shape memory alloy that joins the ends of the double exhaust pipe E so as to overlap each other is formed by spinning or contraction so that the outer diameter is smaller than the inner diameter of the inner cylinder E1. The tubular insertion part 22 and the positioning flange (positioning part) 23 which has an outer diameter larger than the outer cylinder E2 are provided, and the tubular insertion part 22 is heated in the state inserted in the hollow part E1a of the inner cylinder E1. The shape is recovered, and the outer diameter becomes larger than the inner diameter of the outer cylinder E2.

  Next, a description will be given of how to joint the end portions of the inner cylinder E1 and the outer cylinder E2 of the double exhaust pipe E by using the joint pipe 21.

  First, as shown in FIG. 4A, the engine mounting flange E3 is set at a predetermined position of the outer cylinder E2 in which the inner cylinder E1 is accommodated in the hollow portion E2a. These sets can be performed using a dedicated jig (not shown).

  Next, the tubular insertion portion 22 of the joint pipe 21 is inserted into the hollow portion E1a of the inner cylinder E1, and is inserted until the positioning flange 23 comes into contact with the engine mounting flange E3.

  Thereafter, when the joint pipe 21 made of the shape memory alloy is heated as in the previous embodiment, as shown in FIG. 4B, the joint pipe 21 recovers to the memorized shape, that is, the tubular insertion portion 22. Pushes and expands the thin inner cylinder E1 and plastically deforms it, recovers the shape so that the outer diameter of the tubular insertion portion 22 is larger than the inner diameter of the outer cylinder E2, and expands the outer cylinder E2 to mount the engine. Since the inner cylinder E1, the outer cylinder E2, and the engine mounting flange E3 are in contact with each other with extremely high force, the double exhaust pipe E is assembled and the engine mounting flange E3 is pressed against the flange E3. Assembling is easily performed.

  In the joint pipe 21 described above, since welding that was conventionally required for assembling the double exhaust pipe E is not used, it is not necessary to increase the thickness of the inner cylinder E1 in consideration of weldability. The cylinder E1 can be thinned, and a double exhaust pipe E having high performance can be obtained.

  Further, productivity is increased by the amount not using welding, and the end portion of the inner cylinder E1 can be plastically deformed in the step of joining the inner cylinder E1 and the outer cylinder E2 with the joint pipe 21 of the shape memory alloy. Therefore, it is not necessary to perform a plastic working such that the end of the inner cylinder E1 of the double exhaust pipe E is brought into contact with the outer cylinder E2 in advance, and the productivity can be further increased accordingly. Become.

  FIG. 5 shows still another embodiment of the joint pipe of the present invention. Also in this embodiment, the case where the joint pipe of the present invention is used to join the cylindrical members that flow the pressure medium is shown. As shown in FIG. The difference from the joint pipe 1 of the embodiment is that a protrusion 34 as a pressure receiving portion is continuously formed in the circumferential direction on the inner peripheral wall 32 b of the tubular insertion portion 32, and this protrusion 34 is the axis of the tubular insertion portion 32. The other configuration is the same as the joint pipe 1 in the previous embodiment.

  In the joint pipe 31 described above, since the projection 34 as the pressure receiving portion has two inclined surfaces 34a, when a pressure medium is passed through the joined cylindrical member C, the normal direction of the inclined surfaces 34a, 34a (illustrated) The outer wall of the tubular insertion portion 32 of the joint tube 31 is generated in the direction indicated by the arrow) in order to push the joint tube 1 in the direction of expanding its diameter and is in contact with the inner circumferential wall Cb of the tubular member C with a high force. 32a is pressed against the inner peripheral wall Cb of the cylindrical member C with a higher force.

  At this time, since the direction of the pressure contact force is inclined, the force is efficiently concentrated at the center of the protrusion 34, and therefore the sealing performance is further improved by the pressure of the pressure medium.

  In this embodiment, the case where the protrusion 34 is configured by only two inclined surfaces 34a and 34a is shown, but the two inclined surfaces 34a and 34a may be configured to be continuous with a flat surface or a curved surface. The sealing performance of the joined portion of the cylindrical member C is further improved.

  FIG. 6 shows still another embodiment of the joint pipe of the present invention. Also in this embodiment, the case where the joint pipe of the present invention is used to join the cylindrical members that flow the pressure medium is shown. As shown in FIG. The difference from the joint pipe 31 of this embodiment is that a projection 44 as a pressure receiving portion formed continuously in the circumferential direction on the inner peripheral wall 42 b of the tubular insertion portion 42 is inclined with respect to the axis of the tubular insertion portion 42. The other configuration is the same as that of the joint pipe 31 in the previous embodiment, with the configuration having one inclined surface 44a and curved surface 44b.

  In the above-described joint pipe 41, the projection 44 as the pressure receiving portion has one inclined surface 44a and a curved surface 44b. Therefore, when a pressure medium is passed through the joined cylindrical member C, the one inclined surface 44a and the curved surface 44b are curved. Since the pressure of the pressure medium acts in each normal direction of the surface 44b (arrow direction in the figure), the force is efficiently concentrated at the center of the protrusion 44, and the contact force is further increased. As a result, the sealing performance of the joined portion of the cylindrical member C is further improved.

  FIG. 7 shows still another embodiment of the joint pipe of the present invention. Also in this embodiment, the case where the joint pipe of the present invention is used to join the cylindrical members that flow the pressure medium is shown. As shown in FIG. The difference from the joint pipe 31 of the embodiment is that the protrusion 54 as the pressure receiving portion formed continuously in the circumferential direction on the inner peripheral wall 52b of the tubular insertion portion 52 is formed of a curved surface 54b. The other structure is the same as the joint pipe 31 in the previous embodiment.

  Also in the joint pipe 51 described above, since the projection 54 as the pressure receiving portion is formed by the curved surface 54b, when a pressure medium is passed through the joined cylindrical member C, the normal direction of the curved surface 54b (the direction of the arrow in the drawing). Since the pressure of the pressure medium acts, the force is more efficiently concentrated at the center of the protrusion 54 and the contact force is further increased. As a result, the sealing performance of the joint portion of the cylindrical member C is increased. Will be further improved.

  FIG. 8 shows still another embodiment of the joint pipe of the present invention. This embodiment also shows the case where the joint pipe of the present invention is used to join the cylindrical members through which the pressure medium flows. As shown in FIG. 8A, the joint pipe 61 of this embodiment is shown. However, the difference from the joint pipe 31 of the previous embodiment is that the shape is recovered by heating and the outer peripheral wall 62a of the tubular insertion portion 62 that contacts the inner peripheral wall Cb of the cylindrical member C is continuously connected in the circumferential direction. The outward projection 65 is provided, and the outward projection 65 is made softer than the cylindrical member C. Other configurations are the same as the joint pipe 31 in the previous embodiment.

  When the shape of the joint pipe 61 is recovered by heating, the inner peripheral wall Cb of the cylindrical member C and the outer peripheral wall 62a of the tubular insertion portion 62 are continuously connected in the circumferential direction as shown in FIG. In addition, the contact force between the two members increases more effectively, and the outward projection 65, which is softer than the cylindrical member C, positively deforms following the shape of the inner peripheral wall Cb of the cylindrical member C. Since they are in close contact with each other, the contact force between the two members is further increased, and the sealing performance of the joined portion of the cylindrical member C is further improved.

  FIG. 9 shows still another embodiment of the joint pipe of the present invention. Also in this embodiment, the case where the joint pipe of the present invention is used to join the cylindrical members that flow the pressure medium is shown. As shown in FIG. The difference from the joint pipe 61 of this embodiment is that the outward projection 75 is provided separately from the tubular insertion portion 72, and the other configuration is the same as that of the joint pipe 61 of the previous embodiment.

  In the joint pipe 71 described above, since the outward projection 75 is provided separately from the tubular insertion portion 72, a material suitable for the sealing performance is appropriately selected for the outward projection 75 without being limited by the material of the joint pipe 71. can do. For example, the outward projection 75 may be made of a soft material and may be joined to the tubular insertion portion 72 of the joint pipe 71 made of a shape memory alloy by brazing or the like, and the outward projection 75 may be made of a polymer material. Further, the sealing performance may be further improved.

It is sectional explanatory drawing (a) which shows one Example of the joint pipe | tube of this invention, and sectional explanatory drawing (b) of the state which inserted the tubular insertion part in the cylindrical member. Example 1 It is sectional explanatory drawing (a) of the state which has recovered the shape by heating the joint pipe | tube of FIG. 1, and sectional explanatory drawing (b) of the state which poured the pressure medium into the joined cylindrical member. Example 1 It is explanatory drawing (a)-(c) which shows the manufacturing process of the joint pipe | tube of FIG. Cross-sectional explanatory drawing (a) in a state in which the tubular insertion portion of the joint pipe according to another embodiment of the present invention is inserted into the cylindrical member, and cross-sectional explanatory drawing in a state in which the tubular members are joined by heating the joint pipe (b) ). (Example 2) It is a section explanatory view in the state where the tubular member by heating the joint pipe by other examples of the present invention was heated, and the cylindrical members were joined. (Example 3) It is a section explanatory view in the state where the tubular member by heating the joint pipe by other examples of the present invention was heated, and the cylindrical members were joined. (Example 4) It is a section explanatory view in the state where the tubular member by heating the joint pipe by other examples of the present invention was heated, and the cylindrical members were joined. (Example 5) Sectional explanatory drawing (a) of the state which inserted the tubular insertion part of the joint pipe | tube by other Example of this invention in the cylindrical member, and sectional explanatory drawing of the state which heated the joint pipe | tube and joined the cylindrical members ( b). (Example 6) It is a section explanatory view in the state where the tubular member by heating the joint pipe by other examples of the present invention was heated, and the cylindrical members were joined. (Example 7)

Explanation of symbols

1, 21, 31, 41, 51, 61, 71 Fitting tube 2, 22, 32, 42, 52, 62, 72 Tubular insert 2a, 32a, 42a, 52a, 62a Outer peripheral wall of tubular insert 3 Step (positioning) Part)
23 Positioning part flange (positioning part)
32b, 42b, 52b Inner peripheral wall of tubular insertion portion 34, 44, 54 Protrusion (pressure receiving portion)
34a, 44a Inclined surface 44b, 54b Curved surface 65, 75 Outward protrusion d Outer diameter of tubular insertion portion C Tubular member Ca Hollow portion of tubular member Cb Inner circumferential wall of tubular member D Inner diameter of tubular member E1 Inner tube (Cylindrical member)
E2 Outer cylinder (tubular member)

Claims (15)

  A joint pipe made of a shape memory alloy for joining cylindrical members, and having a tubular insertion portion having an outer diameter smaller than the inner diameter of the cylindrical member, and inserting the tubular insertion portion into a hollow portion of the cylindrical member The joint pipe is characterized in that the shape is recovered by heating in a heated state and the outer diameter becomes larger than the inner diameter of the cylindrical member.   A joint pipe made of a shape memory alloy that joins the ends of the cylindrical member facing each other, and includes a tubular insertion portion that is located on both ends and has an outer diameter smaller than the inner diameter of the cylindrical member. A joint pipe, wherein the insertion portion is heated while being inserted into the hollow portion of the cylindrical member, so that the shape is recovered and the outer diameter becomes larger than the inner diameter of the cylindrical member.   A joint pipe made of a shape memory alloy in which ends of double cylindrical members formed by coaxially combining cylindrical members having different diameters are joined to each other, and the small cylindrical member in the double cylindrical member A tubular insertion portion having an outer diameter smaller than the inner diameter of the cylindrical member, and the tubular insertion portion is heated in a state where the tubular insertion portion is inserted into the hollow portion of the small-diameter cylindrical member, so that the inner diameter of the large-diameter cylindrical member is recovered. A joint pipe characterized by having an outer diameter larger than that of the joint pipe.   A pressure receiving portion that concentrates the pressure of the pressure medium flowing through the tubular member as a force in the direction of expanding the tubular insertion portion on the tubular insertion portion that recovers its shape by heating and contacts the inner peripheral wall of the tubular member The joint pipe according to any one of claims 1 to 3, further comprising:   The joint pipe according to claim 4, wherein a projection formed continuously in the circumferential direction on the inner peripheral wall of the tubular insertion portion is used as a pressure receiving portion.   6. The joint pipe according to claim 5, wherein the projection as the pressure receiving portion has at least one inclined surface inclined with respect to the axis of the tubular insertion portion.   The joint pipe according to claim 5, wherein the protrusion as the pressure receiving portion has at least one inclined surface and a curved surface inclined with respect to the axis of the tubular insertion portion.   The joint pipe according to claim 5, wherein the protrusion as the pressure receiving portion is formed of a curved surface.   The joint pipe according to any one of claims 1 to 8, wherein the tubular insertion portion in a stage before being inserted into the hollow portion of the tubular member and heated is tapered.   The joint pipe according to any one of claims 1 to 9, further comprising a positioning portion that determines a predetermined insertion amount of the tubular insertion portion with respect to the hollow portion of the tubular member.   11. The outward projection continuous in the circumferential direction is provided on the outer peripheral wall of the tubular insertion portion that recovers its shape by heating and contacts the inner peripheral wall of the cylindrical member. Fitting tube.   The joint pipe according to claim 11, wherein the outward projection is softer than the cylindrical member.   The joint pipe according to claim 11 or 12, wherein the outward projection is provided separately from the tubular insertion portion.   A tubular insert having an outer diameter smaller than the inner diameter of the tubular member in the joint pipe when joining the end portions of the tubular member facing each other using the joint pipe according to any one of claims 1, 2, 4 to 13. After the portions are inserted into the hollow portions of both cylindrical members, the joint tube is heated to recover the shape so that the outer diameter of the tubular insertion portion is larger than the inner diameter of the cylindrical member, and the ends of the cylindrical members A method for joining cylindrical members using a joint pipe, characterized by joining together.   When joining the end portions of the double cylindrical members formed by coaxially combining the cylindrical members having different diameters using the joint pipe according to any one of claims 1 to 3, the double cylindrical shape After inserting the tubular insertion portion having an outer diameter smaller than the inner diameter of the small-diameter cylindrical member in the member into the hollow portion of the small-diameter cylindrical member, the joint tube is heated to increase the outer diameter of the tubular insertion portion A method for joining tubular members using a joint pipe, wherein the shape is recovered so as to be larger than the inner diameter of the member, and the ends of the double tubular members are joined together.

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