JP6113312B1 - Pipe connection structure - Google Patents

Abstract

Provided is a pipe connecting structure that can easily connect pipe parts and can join the pipe parts to each other with strength. In a state where the second pipe portion is inserted into the enlarged diameter portion, the second pipe portion is formed on a portion of the outer peripheral surface of the second pipe portion facing the first annular groove portion. 103, the second annular groove 104 extending in the circumferential direction, the first annular groove 112, and the second annular groove 104 are inserted into an insertion passage formed by arranging them in the radial direction. And a connecting member 140 that connects the pipe portion 103. The connecting member 140 includes a spring coil that is provided so as to be able to bend along the insertion passage when inserted into the insertion passage. When the spring coil is inserted into the insertion passage, the spring coil is engaged with the inner peripheral surface of the enlarged diameter portion 102 that defines the first annular groove portion 112 and the outer peripheral surface of the second pipe portion 103 that defines the second annular groove portion 104. It is provided to match. [Selection] Figure 2

Description

  The present invention relates to a pipe connection structure that can be used when pipes typically arranged in a building are connected to each other.

  In a building, various piping facilities are generally installed that can circulate fluids such as water and hot water to supply water and hot water. This piping equipment design and installation work is a major factor that affects the quality and construction period of construction work. However, since the majority of the construction period is often spent on building foundation work and steel frame assembly work, in reality, it is required to install the piping equipment within the remaining short period of time. Often.

  Thus, various types of connection structures for various pipes have been proposed. For example, Japanese Utility Model Laid-Open No. 3-130488 discloses a connection structure between a pipe and a joint pipe that receives the pipe. A locking groove is formed at the end of the tube, and an opening is formed in the joint tube at a portion corresponding to the locking groove. Then, the U-shaped locking pin is inserted from the opening of the joint pipe and engaged with the locking groove of the pipe, thereby connecting the pipe and the joint pipe.

  Further, this Japanese Utility Model Laid-Open No. 3-130488 discloses an annular stopper having a claw portion inserted into each opening of the joint pipe as a stopper engaged with the opening of the joint pipe and the locking groove of the pipe. The ingredients are listed. And each claw part engages with each opening part of a joint pipe, and the latching groove of a pipe, and the joint pipe and the pipe are connected.

  The joint mechanism described in Japanese Patent No. 4236033 includes a cylindrical joint body, a stopper member having a shape in which a part of a ring-shaped wire is cut, a pipe to be connected inserted inside the joint body, and this covered body. And an O-ring attached to the outer periphery near the insertion tip of the connecting pipe. And the outer ring groove in which the outer peripheral side edge part of a stopper member is accommodated is formed in the inner peripheral wall of a joint main body, and the stopper member introduction port is formed in the joint main body in which this outer ring groove was formed. .

  This stopper member introduction port is formed wider than the thickness dimension of the wire of the stopper member. Furthermore, an inner ring groove for accommodating the inner peripheral edge of the stopper member is formed at the outer peripheral wall position of the connected pipe farther from the insertion tip side than the O-ring attachment position of the connected pipe. The width dimension of the inner ring groove is formed wider than the thickness dimension of the wire of the stopper member. The stopper member is mounted on the outer peripheral surface of the joint body in a state where a helical twist is applied so that the opposite end portions are slightly misaligned. In addition, the joint structure similar to this joint structure is proposed also in Unexamined-Japanese-Patent No. 2007-270930 and Unexamined-Japanese-Patent No. 2004-239289.

  A pipe joint described in JP 2008-106920 A includes a female member and a male member inserted and connected to the female member. The female member has a cylindrical female main body. The female main body has a male member receiving portion on the front end side and a conduit connecting portion on the rear end side.

  The male member receiving portion is provided with a plurality of locker holes penetrating in the radial direction at predetermined intervals in the circumferential direction of the male member receiving portion. A spherical locker is set in the locker hole and can be displaced in the radial direction.

  A sleeve is attached to the outer periphery of the male member receiving portion. The sleeve can be displaced in the axial direction between a locking position and a locking release position.

  In the locking position, the sleeve presses the locking element radially inward so that the locking element partially protrudes from the inner peripheral surface of the female main body, and in the locking release position, the sleeve The pressing is released, and the locker can be displaced radially outward within the locker hole.

  The male member has a cylindrical male main body. The male main body is formed with an insertion portion that extends from the front end toward the rear end and is inserted into the male member receiving portion of the female main body. When inserted into the member receiving portion, an annular locking recess for receiving the locking element is formed in alignment with the locking element in the radial direction.

Japanese Utility Model Publication No. 3-130488 Japanese Patent No. 4236033 JP 2007-270930 A JP 2004-239289 A JP 2008-106920 A

  However, in the joint described in Japanese Utility Model Laid-Open No. 3-130488, when connecting a pipe and a pipe joint using a U-shaped detachment pin, an opening of the joint pipe and an engagement area of the pin, Both the locking groove of the pipe and the engagement area of the pin are much shorter than the entire circumference of the pipe and the joint pipe.

  Furthermore, even when a pipe and a joint pipe are connected using an annular stopper having a plurality of claw parts, the engagement area of the opening and claw part of the joint pipe, and the engagement area of the engagement groove and claw part Both are much shorter than the entire circumference of the pipe and the joint pipe.

  Thus, since the engagement area | region of a pipe | tube and a joint pipe | tube and a stopper is small, when the internal pressure in a pipe | tube became high pressure, there existed problems, such as a pipe | tube falling out from a joint pipe | tube.

  In the joint mechanism described in the above-mentioned Japanese Patent No. 4236033, when the joint body and the pipe to be connected are connected, the pipe to be connected is inserted into the joint body. Thereafter, the stopper member is sequentially inserted from the stopper member introduction port, and the stopper member is inserted into the inner ring groove and the outer ring groove. The stopper member mounted in the inner ring groove and the outer ring groove is reduced in diameter as compared with the stopper member mounted on the outer peripheral surface of the joint body, and is in a substantially annular state.

  In other words, when the stopper member is mounted on the outer peripheral surface of the joint body, the diameter of the stopper member is increased, and a large surface pressure is generated between the inner peripheral surface of the stopper member and the outer peripheral surface of the joint body. Has occurred.

  For this reason, in order to insert the stopper member into the inner ring groove and the outer ring groove, even if it is attempted to sequentially insert the stopper member portion from the stopper member introduction port, the friction between the stopper member and the joint body is very large. There is a problem that it is very difficult to insert the stopper member into the stopper member introduction port.

  In order to improve the convenience at the time of inserting the stopper portion, it is conceivable to form the stopper member with a thin core wire or the like that can be easily deformed, but it becomes impossible to secure the connection strength between the joint body and the pipe to be connected. For this reason, the stopper member inevitably employs a thick wire. When the ring-shaped stopper member with a part cut away is formed of a wire having a predetermined thickness, the frictional force generated between the outer peripheral surface of the joint body and the stopper member is increased.

  As described above, in the joint mechanism described in the above-mentioned Japanese Patent No. 4236033, both workability when connecting the joint body and the pipe to be connected and strong coupling between the joint body and the pipe to be connected are achieved. Has become difficult.

  In the pipe joint described in Japanese Patent Application Laid-Open No. 2008-106920, a spherical locking element is disposed in a locking hole formed in the male member receiving portion, and the locking element is a female member and a male member. And In order to strengthen the connection between the female member and the male member, it is conceivable to arrange a large number of lockers in the circumferential direction.

  However, in order to arrange a large number of lockers, it is necessary to form a large number of locker holes in the male member receiving part, and it is difficult to ensure the rigidity of the male member receiving part. When the rigidity of the male member receiving portion is lowered, when the internal pressure in the female member and the male member is increased, the upper male member receiving portion is deformed and the coupling between the female member and the male member is released. There is a fear.

  For this reason, in the pipe joint described in Japanese Patent Application Laid-Open No. 2008-106920, it is difficult to make the connection between the pipe portions strong.

  The present invention has been made in view of the problems as described above, and its purpose is to easily connect the tube portions and to connect the tube portions to each other with strength. Is to provide a connection structure.

The pipe connection structure according to the present invention includes a first pipe body including a first pipe main body and a diameter-expanded portion provided at an end of the first pipe main body, and one end inserted into the diameter-expanded portion. Two pipe parts, a stopper part formed between the enlarged diameter part and the first pipe main body and capable of coming into contact with the open end of the second pipe part, and formed on the inner peripheral surface of the enlarged diameter part The first annular groove portion of the outer peripheral surface of the second tube portion in a state where the first annular groove portion extending in the circumferential direction of the enlarged diameter portion and the second tube portion are inserted into the enlarged diameter portion. In the insertion passage formed by arranging the second annular groove and the second annular groove extending in the circumferential direction of the second pipe portion, and the first annular groove and the second annular groove in the radial direction. A connecting member that is inserted and connects the first pipe part and the second pipe part; The enlarged diameter part has an insertion hole through which the outside of the enlarged diameter part communicates with the insertion passage and into which the connecting member is inserted. The connecting member is connected to a spring coil that is bendable along the insertion passage when inserted into the insertion passage, and the spring coil is connected to the insertion passage. A fixed member that is fixed to the outer peripheral surface of the enlarged diameter portion when inserted, and one end of the spring coil are connected, and the insertion is performed when the spring coil is inserted into the insertion passage. And a grip portion disposed outside the hole . When the spring coil is inserted into the insertion passage, an inner peripheral surface of the enlarged diameter portion that defines the first annular groove portion and an outer peripheral surface of the second tube portion that defines the second annular groove portion It is provided to engage with. The enlarged-diameter portion is formed with a recess that is recessed with respect to the outer peripheral surface at a position away from the insertion hole in the circumferential direction. The fixing member is connected to the spring coil, and when the spring coil is inserted into the insertion passage, an extending portion that is disposed outside the insertion hole and has a portion facing the recess, A protrusion formed on the extension and fitted into the recess when the spring coil is inserted into the insertion passage. When the spring coil is inserted into the insertion passage, the enlarged-diameter portion is at least a part of the gripping portion at a position farther from the insertion hole than the gripping portion in the hole axial direction of the insertion hole. And a flange portion provided so as to overlap in the hole axial direction.

  According to the connection structure of a pipe part concerning the present invention, even if the internal pressure in the pipe becomes high, the connection between the pipe parts can be maintained well, and the connection work of the pipe part is reduced. .

It is the side view which carried out the cross sectional view of a part of piping unit 500 provided with pipe part connection structure 200 concerning Embodiment 1. FIG. It is the side view which carried out the cross sectional view of a part of pipe part connection structure 200 concerning Embodiment 1. FIG. It is the front view which looked at a part of pipe part connection structure 200 concerning Embodiment 1 in cross section. It is a sectional side view of the enlarged diameter part 102 shown in FIGS. It is sectional drawing of the enlarged diameter part 102 shown in FIGS. 1-3. FIG. 4 is a cross-sectional view of the prefabricated tube 103 shown in FIGS. 1 to 3. It is a figure for demonstrating the connection member 140 shown in FIGS. 1-3. 4 is a cross-sectional view showing the vicinity of a spring coil 145 in a state in which the connecting member 140 shown in FIGS. 1 to 3 is inserted into an insertion passage 115. FIG. 6 is a cross-sectional view showing a modification of the shape of the annular groove 112. FIG. FIG. 11 is a side view showing a modified example of the connecting member 140. It is the side view which looked at a part of pipe part connection structure 200 concerning Embodiment 2 in section. It is the front view which looked at a part of pipe part connection structure 200 concerning Embodiment 2 in cross section. It is sectional drawing of the enlarged diameter part 102 shown in FIG. 11 and FIG. FIG. 13 is a cross-sectional view of the prefabricated tube 103 shown in FIGS. 11 and 12. It is a figure for demonstrating the connection member 140 shown to FIG. 11 and FIG. It is a front view of the fixing member of the connection member 140 shown in FIG. 11 and FIG. It is a side view of the fixing member of the connection member 140 shown in FIG. 11 and FIG. It is a figure for demonstrating the connection member which concerns on a comparative example. It is a figure which shows the external appearance shape after the destructive test of the prefabricated piping which concerns on an Example. It is a figure which shows the external appearance shape after the destructive test of the connection member which concerns on an Example. It is a figure which shows the external appearance shape after the destructive test of the prefabricated piping which concerns on a comparative example. It is a figure which shows the external appearance shape after the destructive test of the connection member which concerns on a comparative example.

(Embodiment 1)
The connection structure of the prefabricated pipe (pipe part) according to the first embodiment will be described with reference to FIGS. FIG. 1 is a side view of a part of a piping unit 500 provided with the pipe connection structure 200 according to the first embodiment.

  As shown in FIG. 1, the piping unit 500 is configured by connecting a plurality of prefabricated pipes (pipe parts) 100 and 103 to each other by a pipe part connection structure 200. In addition, the piping unit 500 constructed by a plurality of prefabricated pipes as described above is housed in a construction, for example, and used as a water supply piping facility or a hot water supply piping facility.

  FIG. 2 is a side view of a part of the pipe connection structure 200 as a cross-sectional view, and FIG. 3 is a front view of a part of the pipe connection structure 200 as a cross-section. As shown in FIGS. 2 and 3, the pipe connection structure 200 includes a prefabricated pipe 100 (receiving port) having a prefabricated pipe main body 101 and an enlarged diameter portion 102 provided at an end of the prefabricated pipe main body 101, and an opening. The end portion 111 connects to a prefabricated tube 103 (differential port) inserted into the enlarged diameter portion 102.

  The diameter of the inner surface of the enlarged diameter portion 102 is larger than the diameter of the inner surface of the prefabricated pipe body 101. And the end part by the side of the opening end part 111 among the prefabricated pipes 103 is inserted into the enlarged diameter part 102. Since the inner diameter of the enlarged diameter portion 102 is larger than the inner diameter of the prefabricated pipe main body 101, a stepped portion (stopper) 108 is formed between the enlarged diameter section 102 and the prefabricated pipe main body 101.

  The inner diameter of the step portion 108 is smaller than the outer diameter of the opening end portion 111 of the prefabricated tube 103, and when the prefabricated tube 103 is inserted into the enlarged diameter portion 102, the stepped portion 108 has an opening end portion of the prefabricated tube 103. 111 abuts, and relative positioning of the prefabricated pipe 100 and the prefabricated pipe body 101 is performed.

  An annular first annular groove portion 112 (hereinafter simply referred to as an annular groove portion 112) extending along the circumferential direction of the enlarged diameter portion 102 is formed on the inner peripheral surface of the enlarged diameter portion 102. In a state where the prefabricated tube 103 is inserted into the enlarged diameter portion 102, a second annular groove portion 104 (hereinafter simply referred to as an annular groove portion 104) is provided on the outer peripheral surface of the prefabricated tube 103 at a portion opposed to the annular groove portion 112 in the radial direction. Is formed.

  As shown in FIG. 3, the annular groove 112 and the annular groove 104 are arranged in the radial direction, whereby an insertion passage 115 extending in an annular shape is formed. In the enlarged diameter portion 102, an insertion hole 114 that reaches the insertion passage 115 from the outer peripheral surface of the enlarged diameter portion 102 and communicates with the insertion passage 115 is formed. A connecting member 140 is inserted into the insertion hole 114 and the insertion passage 115. The hole axis of the insertion hole 114 is along the tangential direction of the enlarged diameter portion 102.

  FIG. 4 is a side sectional view of the enlarged diameter portion 102. As shown in FIG. 4, a seal housing groove 110 extending in an annular shape is formed in a portion of the inner peripheral surface of the enlarged diameter portion 102 located on the opposite side of the opening end portion 113 with respect to the annular groove portion 112. Yes. In the seal housing groove 110, a seal member 107 is housed as shown in FIG.

  The seal member 107 is formed in an annular shape, and the seal member 107 comes into contact with the outer peripheral surface of the prefabricated pipe 103 inserted into the enlarged diameter portion 102, so that the liquid flowing in the prefabricated pipes 100, 103, etc. Leakage from between the prefabricated pipe 100 and the prefabricated pipe 103 is suppressed.

  Further, the thickness t1 of the enlarged diameter portion 102 is thicker than the thickness t2 of the prefabricated pipe main body 101 shown in FIG. 2, and the rigidity of the enlarged diameter section 102 is higher than that of the prefabricated pipe main body 101.

  FIG. 5 is a cross-sectional view of the enlarged diameter portion 102 taken along line VV in FIG. 4. As shown in FIG. 5, the enlarged diameter portion 102 reaches the annular groove 112 from the outer peripheral surface of the enlarged diameter portion 102. An insertion hole 114 is formed. In the insertion hole 114, a stepped portion 121, a fitting portion 120 formed on the inner peripheral surface located on the annular groove portion 112 side from the stepped portion 121, and the fitting portion 120 extend toward the annular groove portion 112, And a communication path 122 reaching the annular groove 112.

  FIG. 6 is a cross-sectional view of the prefabricated tube 103. As shown in FIG. 6, the annular groove 104 is formed in a semicircular arc shape.

  FIG. 7 is a side view of the connecting member 140. As shown in FIG. 7, the connecting member 140 includes a gripping part 141, a fixing part 142, and a spring coil 145. The gripping part 141 and the fixing part 142 are connected to each other and are formed in a hollow shape. One end portion of the spring coil 145 is passed through the hollow portion of the grip portion 141 and the fixing portion 142 and is fixed thereto.

  The fixed part 142 includes a gripping part 141 and a cylindrical tubular part 143 connected to the gripping part 141. One end of the spring coil 145 is connected to the gripping part 141 through a hollow part provided in the cylindrical part 143. The material constituting the grip portion 141 and the fixing portion 142 may be any material, for example, resin. The fixed portion 142 and one end 145a of the spring coil 145 are integrally formed, for example. In this way, compared with the case where the gripping part 141 and the fixing part 142 and the spring coil 145 are connected by welding, for example, the connection strength between the gripping part 141 and the fixing part 142 and the spring coil 145 can be increased. .

  In the fixing portion 142, the entire spring coil 145 is inserted into the insertion passage 115 at a portion facing the fitting portion 120 on the outer peripheral surface of the cylindrical portion 143 (in other words, the fixing portion 142 is inserted into the insertion hole 114. And a projection 144 that protrudes toward the inner peripheral surface of the insertion hole 114 when the insertion hole 114 is inserted. At this time, the length (height) from the outer peripheral surface to the end in the direction perpendicular to the outer peripheral surface of the cylindrical portion 143 of the convex portion 144 is the insertion hole when the fixing portion 142 is inserted into the insertion hole 114. The distance between the inner peripheral surface 114 and the outer peripheral surface of the cylindrical portion 143 is longer. Moreover, the material which comprises the convex part 144 is resin which has flexibility, such as rubber | gum and a polyurethane, for example. Therefore, when the fixing portion 142 is inserted into the insertion hole 114, the convex portion 144 can come into contact with and press the inner peripheral surface of the insertion hole 114. That is, a predetermined drag can be applied to the contact portion between the fixing portion 142 and the insertion hole 114. Therefore, the connecting member 140 can be held by the convex portion 144 while being inserted into the insertion hole 114 and the insertion passage 115.

  The spring coil 145 is provided such that the length in the axial direction is equal to or greater than the length of the annular groove 104 in the circumferential direction of the enlarged diameter portion 102. The spring coil 145 has a spring coefficient (D−d) / d of 3 or more when the wire diameter d of the spring coil 145 (see FIG. 7) and the outer diameter D of the spring coil 145 (see FIG. 7) are set. It is provided to be 3 or less. The outer diameter D of the spring coil 145 refers to an outer diameter in a region where the outer diameter of the spring coil 145 is constant (details will be described later).

  The spring coil 145 has one end 145a formed integrally with the gripping part 141 and the fixing part 142, and the other end 145b located on the opposite side of the end 145a. The spring coil 145 has a smaller width (outer diameter) in the direction perpendicular to the axial direction at the other end 145b toward the tip end in the axial direction in which the spring coil 145 extends. In other words, the outer diameter of the spring coil 145 is formed so as to taper toward the tip at the other end 145b, but other than that, it is integrally formed with the gripping part 141 and the fixing part 142. The region from the one end 145a to the other end 145b) is provided constant. If the spring coil 145 has such a tapered structure, the connecting member 140 can be easily inserted into the insertion passage 115.

  The connecting member 140 having such a configuration is formed so as to extend linearly in a natural state (an unloaded state in which no load is applied from the outside), and can be deformed to be curved.

  When connecting the prefabricated tube 103 and the prefabricated tube 100, one end of the prefabricated tube 103 is inserted into the enlarged diameter portion 102 of the prefabricated tube 100. When the prefabricated tube 103 is inserted into the enlarged diameter portion 102, the end portion of the prefabricated tube 103 comes into contact with the stepped portion 108 shown in FIG. 2, and the prefabricated tube 100 and the prefabricated tube 103 are positioned.

  When the prefabricated pipe 103 and the prefabricated pipe 100 are relatively positioned, the annular groove 112 and the annular groove 104 are arranged in the radial direction, and the insertion passage 115 is formed. After that, as shown in FIG. 8, one end of the connecting member 140 is inserted into the communication path 122.

  At this time, since the connecting member 140 is formed so as to extend linearly in a natural state, the distal end portion of the connecting member 140 can be positioned relatively easily. Then, after the positioning of the distal end portion of the connecting member 140 is completed, the operator sequentially inserts the distal end portion of the connecting member 140 into the communication path 122. Then, by sequentially inserting the connection member 140 into the communication path 122, the connection member 140 is curved along the shape of the insertion path 115 as shown in FIG. Get in.

  If the spring coefficient (Dd) / d of the spring coil 145 of the connecting member 140 is 3 or more, the connecting member 140 can be bent with a small external force, so that the operator can apply a relatively small force, The connecting member 140 can be sequentially inserted into the insertion passage 115. As shown in FIG. 3, after the entire spring coil 145 is inserted into the insertion hole 114 and the insertion passage 115, the fixing portion 142 is further inserted into the insertion hole 114 to complete the mounting of the connecting member 140. . As a result, the connecting member 140 is disposed over substantially the entire circumference of the insertion passage 115, and the convex portion 144 of the fixing portion 142 and the inner peripheral surface of the insertion hole 114 are in contact with each other.

  When the attachment of the connecting member 140 is completed, the spring coil 145 of the connecting member 140 expands the inner peripheral surface of the enlarged diameter portion 102 that defines the annular groove portion 112 and the outer peripheral surface of the prefabricated tube 103 that defines the annular groove portion 104, respectively. In the circumferential direction of the diameter portion 102 and the prefabricated tube 103, engagement is made over substantially the entire circumference.

  When the internal pressure in the prefabricated pipe 100 and the prefabricated pipe 103 rises, a load is applied to the prefabricated pipe 100 and the prefabricated pipe 103 in a direction in which the prefabricated pipe 103 is removed from the enlarged diameter portion 102.

  At this time, the load applied to the prefabricated tube 100 and the prefabricated tube 103 is received by the spring coil 145 disposed over substantially the entire circumference of the insertion passage 115, so that the spring coil 145 itself is prevented from being deformed or damaged. It is possible to maintain the connection between the tube portions satisfactorily.

  Furthermore, by connecting the prefabricated pipe 100 and the prefabricated pipe 103 via the spring coil 145, the spring coil 145, the prefabricated pipe 100, and the prefabricated pipe 103 can be brought into surface contact, and the spring coil 145 and the prefabricated pipe 100 can be brought into contact with each other. In addition, the contact area with the prefabricated tube 103 can be increased. As a result, even if the load applied to the prefabricated tube 100 and the prefabricated tube 103 is increased in the direction in which the prefabricated tube 103 is removed from the enlarged diameter portion 102, the connecting member is brought into point contact with the two tube portions and engaged with them. Compared with the connection structure of the pipe part provided to do so, the contact area can be widened, and it can be suppressed that the surface pressure at the contact point becomes excessive.

  Thereby, it can suppress that the prefabricated pipe 100 and the prefabricated pipe 103 are deformed or cracked, and the connection state between the prefabricated pipe 100 and the prefabricated pipe 103 can be favorably maintained. The spring coil 145 is made of a metal material such as steel.

  The radius of the arcuate inner surface of the annular groove 104, the radius of the arcuate inner surface of the annular groove 112, and half of the outer diameter D of the spring coil 145 (hereinafter referred to as the radius of the spring coil 145). Each may be substantially matched, but each radius may be set as shown in FIG. FIG. 9 is a cross-sectional view showing the spring coil 145 and the vicinity thereof in a state where the connecting member 140 is inserted into the insertion passage 115.

  As shown in FIG. 9, the radius r1 of the spring coil 145 is smaller than the radii of curvature r2 and r3 of the inner surfaces of the annular grooves 104 and 112. For this reason, when the spring coil 145 is in contact with the inner surface of the annular groove 112, a gap is generated between the spring coil 145 and the annular groove 104. Thus, the cross-sectional area of the insertion passage 115 defined by the annular groove 104 and the annular groove 112 is larger than the cross-sectional area perpendicular to the axial direction of the spring coil 145 (the area of a circle having the outer diameter D as a diameter). The connecting member 140 can be easily inserted into the insertion passage 115. Further, when the connecting member 140 is inserted into the insertion passage 115, the annular groove 112 and the annular groove 104 are not accurately arranged in the radial direction, and the annular groove 112 and the annular groove 104 are prefabricated pipes 100, 103. Even if the connecting member 140 is slightly displaced in the extending direction, the connecting member 140 can be easily inserted into the insertion passage 115, and the connection work between the prefabricated pipe 100 and the prefabricated pipe 103 can be made more efficient. ing.

  Here, the spring coil 145 of the connecting member 140 is formed to be linear in a natural state. For this reason, in a state where the connecting member 140 is inserted into the insertion passage 115 and is curved, an urging force is generated in the spring coil 145 to return to the linear shape. Accordingly, the spring coil 145 presses the inner peripheral surface of the enlarged diameter portion 102 that defines the annular groove portion 112 and enters the annular groove portion 112.

  As shown in FIG. 9, the spring coil 145 is formed to have an annular shape in a cross section perpendicular to the axial direction, and the outer peripheral surface of the spring coil 145 is formed to have a circular shape. The radius r1 (half the outer diameter D as described above) of the outer peripheral surface of the spring coil 145 is formed to be thicker than the thickness t3 of the prefabricated tube 103.

  The lateral stiffness of the spring coil 145 is higher than that of the prefabricated tube 103, and deformation of the spring coil 145 in the radial direction is suppressed. On the other hand, the radial thickness t1 in the portion where the annular groove portion 112 is located in the enlarged diameter portion 102 is formed to be thicker than the radius r1 of the spring coil 145, and the rigidity of the enlarged diameter portion 102 is increased. Is formed so as to be higher than the prefabricated tube 103. For this reason, even if the internal pressure in the prefabricated tubes 100 and 103 increases, the deformation of the enlarged diameter portion 102 is suppressed.

  And even if the internal pressure in the prefabricated tubes 100 and 103 rises, the enlarged diameter portion 102 hardly deforms. On the other hand, the prefabricated tube 103 is deformed so as to expand its diameter. At this time, since the prefabricated tube 103 is more easily deformed than the enlarged diameter portion 102, the inner surface of the annular groove portion 104 is deformed so as to be in close contact with the outer peripheral surface of the spring coil 145 located in the annular groove portion 112.

  As a result, the inner surface of the annular groove portion 104 and the outer peripheral surface of the spring coil 145 are in close contact with each other, and the spring coil 145 has entered the annular groove portion 112, so that the prefabricated tube 100 and the prefabricated tube 103 are more coupled. It will be solid. Since the spring coil 145 enters the annular groove portion 112 that is difficult to be deformed by the urging force, even if the prefabricated tube 103 is deformed, the spring coil 145 is prevented from falling off.

  Furthermore, since the biasing force of the spring coil 145 can be sufficiently increased by setting the spring coefficient (Dd) / d of the spring coil 145 of the connecting member 140 to 3.3 or less, the prefab tube 100 and the prefab The coupling with the tube 103 can be made stronger.

  FIG. 9 is a cross-sectional view showing a modification of the shape of the annular groove 112. In the example shown in FIG. 9, the inner surface of the annular groove 112 is formed by a curved surface 112a centered on the center point O4 and a curved surface 112b centered on the center point O5. The center point O4 and the center point O5 are separated in the extending direction of the prefabricated tube 103.

  The curvature radii r4 of the curved surfaces 112a and 112b are both longer than the radius r1 of the spring coil 145. In the annular groove 112 shown in FIG. 10, the curved surfaces 112 a and 112 b rise steeply from the bottom of the annular groove 112, so that the spring coil 145 is less likely to fall off the annular groove 112.

  As described above, according to the pipe part connection structure 200 according to the present embodiment, the prefabricated pipe 103 is inserted into the enlarged diameter part 102 of the prefabricated pipe main body 101, and the connecting member 140 is inserted into the insertion passage 115 from the insertion hole 114. By inserting and pushing the fixing portion 142 into the insertion hole 114 until the convex portion 144 and the fitting portion 120 come into contact with each other, the connection work between the prefab tube 100 and the prefab tube 103 can be completed. The connection work with the prefabricated pipe 103 can be simplified. Furthermore, according to the pipe part connection structure 200 according to the present embodiment, even if the internal pressure in the prefabricated pipes 100 and 103 is increased, the connection between the prefabricated pipes 100 and 103 can be favorably maintained.

  As shown in FIG. 3, the cylindrical portion 143 of the connecting member 140 is located in the communication path 122, and the cylindrical portion 143 is not engaged with the annular groove portion 104 of the prefabricated pipe 103. Therefore, by forming the cylindrical portion 143 with a material that is less expensive than the spring coil 145, the manufacturing cost of the connecting member 140 can be reduced.

  In addition, in FIG. 1 to FIG. 9 described above, the case where the connecting member 140 is linear in a no-load state has been described, but is not limited thereto. FIG. 10 shows a modification of the connecting member 140 shown in FIG. As shown in FIG. 10, the connecting member 140 may be curved so that at least a part thereof has a curvature radius R5 in an unloaded state.

  The curvature radius R5 is formed to be larger than the radius of the enlarged diameter portion 102 or the prefabricated tube 103, for example. When such a connecting member 140 is inserted from the insertion hole 114 and the prefabricated tube 103 and the enlarged diameter portion 102 are connected, the connecting member 140 presses the spring coil 145 against the annular groove 112 of the enlarged diameter portion 102.

  By pressing the spring coil 145 against the annular groove 112, it is possible to obtain the same effects as those of the connecting member 140 shown in FIG.

  Although the connecting members 140 shown in FIG. 7 are formed in a straight line, these connecting members 140 are set so that the radius of curvature is much larger than the radius of the expanded portion 102 and the prefabricated tube 103. is there.

  In other words, when the connecting member 140 is inserted into the insertion passage 115 by making the curvature radius of the connecting member 140 larger than that of the enlarged diameter portion 102 and the prefabricated tube 103, the spring coil 145 is biased by the biasing force of the spring coil 145. Can be pressed against the annular groove 112 of the enlarged diameter portion 102.

  Thereby, even if the internal pressure of the prefabricated pipes 100 and 103 increases as described above, the connected state of the prefabricated pipe body 101 and the prefabricated pipe 103 can be maintained.

  In the present embodiment, the example in which the connection structure of the pipe portion according to the present invention is applied to the connection structure of the prefabricated pipe has been described. However, the present invention is not limited to the prefabricated pipe and is applicable to the connection structure of other pipe parts. can do.

  Here, although there is a part which overlaps with embodiment mentioned above, the characteristic structure of this embodiment is enumerated.

  The connection structure of the pipe part according to the present embodiment includes a first pipe part 100 including a first pipe main body 101 and a diameter-expanded part 102 provided at an end of the first pipe main body 101, and one end of the diameter-expanded part 102. A second pipe portion 103 inserted into the first pipe body 103, a stopper portion that is formed between the enlarged diameter portion 102 and the first pipe main body 101 and can be brought into contact with the open end portion of the second pipe portion 103, and the enlarged diameter portion 102. The outer peripheral surface of the second pipe portion 103 in a state where the first annular groove 112 and the second pipe portion 103 inserted in the enlarged diameter portion 102 are formed in the inner peripheral surface and extending in the circumferential direction of the enlarged diameter portion 102. Of these, the second annular groove portion 104 formed in a portion facing the first annular groove portion 112 and extending in the circumferential direction of the second tube portion 103, and the first annular groove portion 112 and the second annular groove portion 104 are arranged in the radial direction. The first pipe part 100 and the second pipe part are inserted into the insertion passage 115 formed by And a connecting member 140 for connecting the 03.

  The enlarged diameter portion 102 is formed with an insertion hole 114 through which the outside of the enlarged diameter portion 102 communicates with the insertion passage 115 and into which the connecting member 140 is inserted. The connecting member 140 includes a spring coil 145 provided so as to be able to bend along the insertion passage 115 when inserted into the insertion passage 115. When the spring coil 145 is inserted into the insertion passage 115, the inner peripheral surface of the enlarged diameter portion 102 that defines the first annular groove portion 112 and the outer peripheral surface of the second tube portion 103 that defines the second annular groove portion 104. It is provided to engage with.

  In this way, when the connecting member 140 is inserted into the insertion passage 115, the spring coil 145 can be pressed against the annular groove 112 of the enlarged diameter portion 102 by the urging force of the spring coil 145. Thereby, even if the internal pressure of the prefabricated pipes 100 and 103 increases as described above, the connected state of the prefabricated pipe body 101 and the prefabricated pipe 103 can be maintained. That is, even if the internal pressure in the pipe increases, the connection between the pipe sections can be maintained satisfactorily.

(Embodiment 2)
Next, with reference to FIG. 11 to FIG. 17, a pipe connection structure according to the second embodiment will be described. The pipe connection structure according to the second embodiment has basically the same configuration as the pipe connection structure according to the first embodiment, except that the connecting member 140 is provided in the insertion passage 115 instead of the fixing part 142. It is different in that it includes a fixing member 150 that is fixed to the outer peripheral surface of the enlarged diameter portion 102 when inserted into the outer diameter.

  As shown in FIG. 13, the enlarged-diameter portion 102 has basically the same configuration as the enlarged-diameter portion 102 shown in FIG. 5, but differs in that the fitting portion 120 is not formed in the insertion hole 114. . The end of the insertion hole 114 positioned on the outer peripheral side has a larger diameter than the communication path 122 in the radial direction, and the planar shape of the opening when the enlarged diameter portion 102 is viewed from the side is an elliptical shape. The insertion hole 114 does not fit the connection member 140 when the connection member 140 is inserted into the insertion passage 115.

  As shown in FIG. 13, the enlarged diameter portion 102 has a thick portion 123 provided so as not to interfere with the gripping portion 141 of the connecting member 140 when the spring coil 145 is inserted into the insertion passage 115, A flange portion 124 that is formed on the thick portion 123 and overlaps at least a part of the grip portion 141 in the hole axial direction of the insertion hole 114 is provided. The distance between the insertion hole 114 and the flange portion 124 in the axial direction of the insertion hole 114 is the length of the gripping portion 141 in the axial direction of the spring coil 145 and the thickness of the fixing member 150 (distance between the main surfaces). It is more than the sum.

  As shown in FIG. 13, the enlarged diameter portion 102 is formed with a recess 125 that is recessed with respect to the outer peripheral surface at a position away from the insertion hole 114 in the circumferential direction. The minimum angle θ formed by the recess 125 and the insertion hole 114 with respect to the center point O6 of the enlarged diameter portion 102 in the cross section perpendicular to the extending direction of the prefabricated pipe body 101 is, for example, 180 ° or less, and preferably 90 °. Or less, more preferably 45 °. The planar shape of the concave portion 125 when the enlarged diameter portion 102 is viewed from the side may be any shape, for example, a circular shape. The inner diameter W1 of the recess 125 is narrower (smaller) than the outer diameter W2 (see FIG. 17) of the protrusion 153 of the fixing member 150 of the connecting member 140 described later.

  As shown in FIGS. 11 and 13, the enlarged diameter portion 102 has an outer peripheral surface 126 connected to the opening end portion 113. The outer peripheral surface 126 is formed so as to extend in the circumferential direction of the enlarged diameter portion 102. As shown in FIG. 11, for example, a portion of the outer peripheral surface 126 farthest from the opening end 113 in the axial direction of the enlarged diameter portion 102 overlaps a part of the first annular groove 112 in the radial direction of the enlarged diameter portion 102. It is formed to extend to a position. The outer peripheral surface 126 is located closer to the opening end 113 than the insertion hole 114 in the axial direction of the enlarged diameter portion 102.

  As shown in FIG. 14, the prefabricated tube 103 has basically the same configuration as the prefabricated tube 103 shown in FIG. 6, but the inner diameter of the open end 111 is equal to the annular groove 104 and the open end of the prefabricated tube 103. The difference is that it is smaller than the inner diameter of the portion other than 111. The outer diameter of the opening end 111 is larger than the inner diameter of the step 108.

  As shown in FIG. 15, the connecting member 140 has basically the same configuration as the connecting member 140 shown in FIG. 7, but is different in that it further includes a fixing member 150. As shown in FIGS. 11 and 12, the fixing member 150 is fixed to the outer peripheral surface of the enlarged diameter portion 102 when the spring coil 145 is inserted into the insertion passage 115.

  As shown in FIGS. 15 to 17, the fixing member 150 has an extending portion 151 and a protruding portion 153. The shape of the extending portion 151 is, for example, a ribbon shape. A through hole 152 is formed at one end of the extending portion 151 so as to connect the main surfaces. The extending portion 151 is connected to the spring coil 145 by passing the spring coil 145 through the through hole 152. As a result, the fixing member 150 is connected to the connecting member 140. The diameter of the through hole 152 is equal to or smaller than the outer diameter of the spring coil 145, and the fixing member 150 may be fixed to the connecting member 140. The material constituting the fixing member 150 may be any material having flexibility. In the extended portion 151, the thickness (distance between the main surfaces) T1 of the portion where the through hole 152 is formed is thinner than the thickness (distance between the main surfaces) T2 of the portion where the protrusion 153 is formed, for example. .

  As shown in FIGS. 11 and 12, the extended portion 151 is, for example, entirely disposed outside the insertion hole 114 when the spring coil 145 is inserted into the insertion passage 115. The extending portion 151 has a portion facing the recess 125 and a portion facing the outer peripheral surface 126 when the spring coil 145 is inserted into the insertion passage 115. The protruding portion 153 protrudes on the main surface of the portion of the extending portion 151 that faces the concave portion 125. The protruding portion 153 may be formed on the other end of the extending portion 151 (on the side opposite to the one end where the through hole 152 is formed). For example, the protruding portion 153 is formed on one end side with respect to the other end of the extending portion 151. ing. In other words, the other end of the extending portion 151 is formed at a position farther from the protruding portion 153 than the through hole 152.

  The outer diameter W2 (see FIG. 17) of the protrusion 153 is equal to or larger than the inner diameter W1 (see FIG. 13) of the recess 125 of the enlarged diameter portion 102. The protrusion 153 has, for example, a relatively wide portion and a narrow portion in a direction perpendicular to the main surface of the extending portion 151, and the outer diameter of the wide portion is W2. The outer diameter of the narrow portion of the protrusion 153 is, for example, not more than the inner diameter W1 of the recess 125. The protrusion 153 can be fitted into the recess 125 when the spring coil 145 is inserted into the insertion passage 115.

  The fixing member 150 is provided, for example, so that tension is applied to the extending portion 151 when the spring coil 145 is inserted into the insertion passage 115 and the protrusion 153 is fitted into the recess 125. When the fixing member 150 of the connecting member 140 is fixed to the outer peripheral surface of the enlarged diameter portion 102, the minimum formed by one end and the other end of the extending portion 151 of the fixing member 150 with respect to the center point O6 of the enlarged diameter portion 102 The angle is equal to or smaller than the minimum angle θ formed by the recess 125 and the insertion hole 114 with respect to the center point O6 of the enlarged diameter portion 102.

  As shown in FIG. 16, the extending portion 151 may have a bent shape in plan view. For example, the portion where the protrusion 153 is formed may be connected to the portion where the through hole 152 is formed via an inclined portion 154 extending in a direction intersecting the extending direction of the portion. A portion where the through hole 152 is formed in the extending portion 151 is disposed at a position overlapping the insertion hole 114 in the hole axial direction of the insertion hole 114 when the spring coil 145 is inserted into the insertion passage 115. A portion of the extending portion 151 where the protruding portion 153 is formed is disposed at a position overlapping the outer peripheral surface 126 in the radial direction of the enlarged diameter portion 102 when the spring coil 145 is inserted into the insertion passage 115. The part 153 is fitted into the recess 125. The inclined portion 154 of the extending portion 151 is formed with a through hole 152 in the extending portion 151 when the spring coil 145 is inserted into the insertion passage 115 and the protruding portion 153 is fitted into the recess 125. It arrange | positions so that a part may be orthogonally crossed. Since the extending portion 151 has the inclined portion 154, as described above, the outer peripheral surface 126 and the insertion hole 114 are provided at positions that do not overlap with each other in the axial direction of the enlarged diameter portion 102. In addition, the extending portion 151 can be fixed without being twisted around the enlarged diameter portion 102.

  According to the pipe connecting structure according to the second embodiment, when the connecting member 140 is inserted into the insertion passage 115, at least a part of the gripping portion 141 and the flange portion 124 overlap in the hole axial direction of the insertion hole 114. As a result, the connecting member 140 can be prevented from coming out of the insertion passage 115. Further, when the connecting member 140 is inserted into the insertion passage 115, the protrusion 153 of the fixing member 150 is fitted into the recess 125, and the fixing member 150 is fixed to the outer peripheral surface of the enlarged diameter portion 102. It is possible to prevent the member 140 from coming out of the insertion passage 115.

  Further, when the fixing member 150 of the connecting member 140 is fixed to the outer peripheral surface of the enlarged diameter portion 102, the extended portion 151 is disposed along the circumferential direction of the enlarged diameter portion 102. When viewed, the extension 151 can be visually recognized. The longer the extension portion 151 is, the longer the fixing member 150 extends from the center point O6 of the enlarged diameter portion 102 when the fixing member 150 of the connecting member 140 is fixed to the outer peripheral surface of the enlarged diameter portion 102. The minimum angle formed by one end and the other end of the portion 151 is reduced, and the visibility of the extending portion 151 when the enlarged diameter portion 102 is viewed from the side is improved. When the fixing member 150 is normally fixed to the enlarged diameter portion 102, tension is applied to the extending portion 151, and no twisting or loosening occurs. On the other hand, when the fixing member 150 is not normally fixed to the enlarged diameter portion 102, for example, when the protruding portion 153 is removed from the concave portion 125, at least a part of the extending portion 151 is the outer peripheral surface of the enlarged diameter portion 102. Detach from 126. Further, when the connecting member 140 is not inserted into the insertion passage 115, the extending portion 151 does not exist. Therefore, by visually recognizing the extension part 151, it is possible to confirm whether there is an abnormality such as a disconnection of the connecting member 140 from the state of the extension part 151.

  The extending portion 151 is preferably colored in a color different from the outer peripheral surface of the enlarged diameter portion 102. Thereby, the visibility of the extension part 151 can be improved. Moreover, in the piping group provided with a plurality of pipe portion connection structures according to Embodiment 2, the plurality of extending portions 151 may be colored in different colors. For example, the plurality of extending portions 151 may be colored in different colors depending on the size of the tube portion (in other words, the size of the connecting member 140 necessary for fixing the connection structure of the tube portion). Good. In this way, it can be confirmed whether or not the connecting member 140 suitable for the size of the pipe portion is inserted into the insertion passage 115. Moreover, the extending part 151 may be comprised with the fluorescent material, and the fluorescent paint may be apply | coated to the surface. In this way, the visibility of the extending part 151 can be improved even in a dark place.

  In the pipe connection structure according to the second embodiment, the fixing member 150 is fitted to the outer peripheral surface of the enlarged diameter portion 102 by fitting the projection 153 of the fixing member 150 and the recessed portion 125 of the enlarged diameter portion 102. It is fixed, but it is not limited to this. A protruding portion that protrudes from the outer peripheral surface 126 may be formed on the outer peripheral surface 126 of the enlarged diameter portion 102. A through hole into which the protrusion can be inserted may be formed in the fixing member 150. Even in this case, the fixing member 150 can be fixed to the outer peripheral surface of the enlarged diameter portion 102 by inserting the protruding portion of the enlarged diameter portion 102 into the through hole of the fixing member 150.

Next, examples according to the present embodiment will be described.
(Example)
As the pipe connection structure according to the example, the pipe connection structure according to the present embodiment is employed. Specifically, the prefabricated pipes 100 and 103 are stainless steel pipes (SUS-TPD) for general piping having an outer diameter of 114.3 mm, the expanded diameter portion 102 is cast stainless steel (SCS13), and the sealing member 107 is packed (EPDM). The spring coil 145 was a spring stainless steel wire (SUS304WPB) having an outer diameter D of 5.5 mm. The radius of the arc-shaped inner surface of the annular groove 104 of the prefabricated tube 103 (differential port) and the radius of the arc-shaped inner surface of the annular groove 112 of the enlarged diameter portion 102 (receiving port) are 3 mm, respectively. did.

(Comparative example)
As the connection structure of the pipe part according to the comparative example, basically, the connection structure of the pipe part according to the present embodiment has the same configuration, but only the connection member is different. Specifically, referring to FIG. 18, the connecting member according to the comparative example includes a flexible core wire, a spherical body in which a through hole is formed and the core wire is inserted, and a plurality of spherical bodies arranged on the core wire. It was supposed to have. SUS304WPB having a diameter of 1.4 mm was used for the core wire, and a steel ball (SUS304) having a diameter of 6.3 mm was used for the spherical body.

(Test method)
The connection structure of the pipe part of the example and the comparative example was set in an Amsler universal testing machine (manufactured by Tokyo Test Equipment Co., Ltd .; hydraulic type, maximum capacity 200 kN), and 0.2 MPa of air pressure was sealed inside the pipe part. The tube was pulled out at a tensile strength of 2 mm / min, and the maximum load until air leaked was measured. In addition, the test method was based on SAS322 (the pipe joint performance standard of the stainless steel pipe for general piping). After the measurement (after destruction), the external appearance was visually observed with respect to the connection structure of the pipe portion of the example and the comparative example.

(result)
The test results will be described with reference to FIGS. In the pipe connection structure according to the example, air leaked when a load of 110 kN was applied (the pipe connection structure was broken). FIG. 19 shows the external shape of the prefabricated tube 103 (differential port) according to the embodiment after destruction. FIG. 20 shows the external shape of the connecting member 140 according to the embodiment after destruction. Although the number of depressions corresponding to the number of windings of the spring coil 145 was formed on the outer peripheral surface of the prefabricated tube 103, the spring coil 145 had no scratches that could be observed with the naked eye.

  On the other hand, in the pipe connection structure according to the comparative example, air leaked when a load of 90 kN was applied. FIG. 21 shows the external shape of a prefabricated pipe (fitting port) according to a comparative example after destruction. FIG. 22 shows the external shape of the connecting member according to the comparative example after destruction. On the outer peripheral surface of the prefabricated tube 103, dents were formed at the number and position corresponding to the number and interval of the spherical bodies, and there were scratches that could be visually observed on the spherical body. The scratch is considered to be formed when the spherical body rides on the outer peripheral surface of the prefabricated pipe from the annular groove portion of the prefabricated pipe.

  That is, in the connection structure of the pipe part which concerns on an Example, the fracture load was 122% larger compared with the connection structure of the pipe part which concerns on a comparative example. This is because the contact area between the spring coil and the prefab tube in the pipe connection structure according to the embodiment is larger than the contact area between the spherical body and the prefab pipe in the pipe connection structure according to the comparative example. Even if the internal pressure increases, it is considered that the connection between the pipe portions could be maintained satisfactorily.

  Although the embodiment of the present invention has been described above, it should be considered that the embodiment disclosed this time is illustrative and not restrictive in all respects. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention is suitable for a pipe connection structure.

DESCRIPTION OF SYMBOLS 100 Prefab pipe (1st pipe part), 101 Prefab pipe main body, 102 Diameter expansion part, 103 Prefab pipe (2nd pipe part), 104 2nd annular groove part, 107 Seal member, 108,121 Step part, 110 Seal accommodation groove 111, 113 Open end portion, 112 First annular groove portion, 112a, 112b Curved surface, 114 Insertion hole, 115 Insertion passage, 120 Fitting portion, 122 Communication passage, 140 Connection member, 141 Holding portion, 142 Fixing portion, 143 Tube part, 144 convex part, 145 spring coil, 200 pipe part connection structure, 500 piping unit.

Claims (6)

A first pipe body including a first pipe main body and an enlarged diameter portion provided at an end of the first pipe main body;
A second pipe part, one end of which is inserted into the enlarged diameter part,
A stopper portion that is formed between the enlarged diameter portion and the first tube main body and is capable of contacting the open end portion of the second tube portion;
A first annular groove formed on an inner peripheral surface of the enlarged diameter portion and extending in a circumferential direction of the enlarged diameter portion;
In the state where the second pipe portion is inserted into the enlarged diameter portion, the outer peripheral surface of the second pipe portion is formed at a portion facing the first annular groove portion, and is formed in a circumferential direction of the second pipe portion. A second annular groove extending;
The first annular groove portion and the second annular groove portion are inserted into an insertion passage formed by arranging in a radial direction, and include a connecting member that connects the first tube portion and the second tube portion,
The enlarged diameter portion is formed with an insertion hole through which the outside of the enlarged diameter portion communicates with the insertion passage and into which the connecting member is inserted.
The connecting member is connected to a spring coil that is bendable along the insertion passage when inserted into the insertion passage, and the spring coil is connected to the insertion passage. A fixed member that is fixed to the outer peripheral surface of the enlarged diameter portion when inserted, and one end of the spring coil are connected, and the insertion is performed when the spring coil is inserted into the insertion passage. Including a grip portion disposed outside the hole ,
When the spring coil is inserted into the insertion passage, an inner peripheral surface of the enlarged diameter portion that defines the first annular groove portion and an outer peripheral surface of the second tube portion that defines the second annular groove portion Is provided to engage with ,
In the enlarged diameter portion, a recessed portion that is recessed with respect to the outer peripheral surface is formed at a position away from the insertion hole in the circumferential direction,
The fixing member is connected to the spring coil, and when the spring coil is inserted into the insertion passage, an extending portion that is disposed outside the insertion hole and has a portion facing the recess, Formed on the extending portion, and having a projection that fits into the recess when the spring coil is inserted into the insertion passage,
When the spring coil is inserted into the insertion passage, the enlarged-diameter portion is at least a part of the gripping portion at a position farther from the insertion hole than the gripping portion in the hole axial direction of the insertion hole. And a connecting structure for a pipe part , further comprising a flange part provided so as to overlap in the hole axial direction .   The connection structure of the pipe part according to claim 1, wherein a spring index of the spring coil is 3 or more and 3.3 or less. Before Symbol spring coil, at the other end located opposite the one end connected to the grip portion, in the axial direction until toward the tip portion in the axial direction of extension of the spring coil The pipe portion connection structure according to claim 1 or 2, wherein a width in a vertical direction is small, and the width is constant from the one end to the other end . The fixing member is provided so that tension is applied to the extension when the spring coil is inserted into the insertion passage and the protrusion is fitted into the recess. The pipe connection structure according to any one of claims 1 to 3. The minimum angle formed by the recess and the insertion hole with respect to the center point of the enlarged diameter portion is 90 degrees or less,
The minimum angle formed by one end and the other end of the extending portion of the fixing member with respect to the center point of the enlarged diameter portion is such that the recess and the insertion hole are located with respect to the center point of the enlarged diameter portion. The connection structure of the pipe part according to any one of claims 1 to 4, which is equal to or less than the minimum angle formed.   The tube portion according to any one of claims 1 to 5, wherein a hole diameter of an end portion positioned on an outer peripheral side in the insertion hole is larger than a hole diameter of a portion of the insertion hole connected to the insertion passage. Connection structure.