Joint for flexible pipe

Abstract

To provide a joint for a flexible pipe capable of more reliably achieving seal performance by enabling a retainer claw part to be placed in a proper position even in the case that a flexible pipe is obliquely inserted.SOLUTION: A joint 1 for a pipe is a joint which includes a retainer 7, a seal member 6, an elastic member 4 held in a compressed state, and a release mechanism that holds the elastic member 4 in a compressed state and releases the compressed state of the elastic member 4 by inserting a flexible pipe inside a joint body 2, makes the seal member 6 slide by releasing the compressed state of the elastic member 4, and brings the retainer 7 into engagement by the slide. When the compressed state of the elastic member 4 is released, a claw part 71 is provided such that an axial position P of a tip part 711a on a back side of the joint body 2 in the claw part 71 overlaps an axial region R between the deepest part of a valley part v3 being an engagement object of the flexible pipe T and a peak of a crest part adjacent to the valley part v3 on an opposite tip side of the flexible pipe T.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a flexible pipe joint to which a bellows-shaped flexible pipe is connected. [Background technology]

[0002] Metal bellows-shaped flexible pipes are widely used for indoor gas piping, etc. Various pipe fittings are used to connect these flexible pipes to gas valves, steel pipes, etc. In recent years, one-touch pipe fittings have also been put into practical use, which allow installation to be completed simply by inserting the flexible pipe into the pipe fitting without the need for tools.

[0003] For example, a flexible pipe joint (hereinafter simply referred to as a pipe joint) described in Patent Document 1 is shown in Fig. 8. As shown in Fig. 8, pipe joint 11 includes joint body 12 into which a flexible pipe T (see Fig. 9) is inserted from one end, and within joint body 12 are arranged a part of press nut 13, elastic member 14 that is expandable and contractible in the axial direction, release mechanism 15 that holds elastic member 14 in a compressed state and releases this compressed state, ring-shaped seal member 16 that comes into close contact with flexible pipe T, and retainer 17. In Fig. 8, release mechanism 15 has holding member 15a that holds elastic member 14 in a compressed state and moving member 15b. Furthermore, retainer 17 has a plurality of claws 17a that are arranged at intervals in the circumferential direction.

[0004] The operation of this pipe joint during the connecting process is shown in Figure 9. Figure 9 is a cross-sectional view of the upper half of the pipe joint. As shown in Figure 9, when the flexible pipe T is inserted straight into one end of the pipe joint 11, the tip of the flexible pipe T comes into contact with the moving member 15b (see Figure 9(a)). Furthermore, the moving member 15b moves toward the back of the joint body 12 in response to the insertion of the flexible pipe T. The flexible pipe T is then inserted all the way to the back. At this time, as the moving member 15b moves, the claws of the retaining member 15a disengage from the inner circumferential groove of the joint body 12, and the compressed state of the elastic member 14 is released (see Figure 9(b)). As a result, the elastic member 14 expands, and the resulting expansion force causes the sealing member 16 to slide toward the inlet side of the joint body 12. As the seal member 16 slides, the inclined surface of the retainer 17 comes into close contact with the inclined surface of the press nut 13, and the inner diameter tip surfaces of the claw portions 17a are reduced in diameter and fit into the valley portions of the flexible pipe T (see FIG. 9(c)). In FIG. 9(c), the third valley portion v3 counting from the tip end Ta of the flexible pipe T is the valley portion to be engaged, and all of the multiple claw portions 17a of the retainer 17 fit into that valley portion v3. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-52762 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when connecting a flexible pipe, it can be difficult to insert the flexible pipe straight into a pipe fitting. For example, when a flexible pipe whose other end is already connected to a device or a pipe fitting is to be bent and connected to another pipe fitting, the flexible pipe must be inserted into the pipe fitting while being pulled, which can lead to the flexible pipe being unintentionally inserted at an angle.

[0007] When the flexible pipe is inserted at an angle, the tip of the flexible pipe makes contact with the annular end face of the movable member in an offset manner. If the movable member moves in this state and the compressed state of the elastic member is released, the seal member will slide with the sliding axis tilted relative to the central axis of the flexible pipe, which may result in variations in the valleys into which the claws of the retainer fit.

[0008] As an example, Figure 10 shows a state in which the claw portions 17a of the retainer 17 are fitted into the second valley portion v2 and the third valley portion v3 counting from the tip Ta of the flexible pipe T and connected (hereinafter referred to as "2 / 3 valley engagement" in this specification). The claw portions 17a of the retainer 17 would normally be fitted entirely into the third valley portion v3 (the valley portion to be engaged), but in Figure 10, part of the claw portions 17a are fitted into the second valley portion v2. As a result, the flexible pipe T is connected in a state in which the central axis Q of the flexible pipe T is tilted with respect to the central axis O of the pipe fitting 11.

[0009] In this state, uneven adhesion occurs in the circumferential direction of the seal member 16 relative to the flexible pipe T. For example, in Figure 10, the interference between the upper outer peripheral surface of the flexible pipe T and the seal member 16 is sufficient, while the interference between the lower outer peripheral surface of the flexible pipe T and the seal member 16 is shallow. If an external bending force is further applied to the flexible pipe T in a predetermined direction in this state, the interference of the seal member 16 will further decrease, and it is thought that sufficient sealing performance will not be obtained.

[0010] The present invention has been made in consideration of the above circumstances, and aims to provide a coupling for flexible pipes that can store the claws of the retainer in the appropriate position even when the flexible pipe is inserted at an angle, thereby achieving more reliable sealing performance. [Means for solving the problem]

[0011] The flexible pipe joint of the present invention is a flexible pipe joint for connecting a bellows-shaped flexible pipe having a plurality of peaks and valleys arranged alternately along the axial direction, and the flexible pipe joint comprises a joint body into which the flexible pipe is inserted from one end, and inside the joint body are a retainer having a plurality of claws that engage with the flexible pipe, a ring-shaped sealing member that comes into close contact with the flexible pipe, an elastic member held in a compressed state, and a release mechanism that holds the elastic member in a compressed state and releases the compressed state of the elastic member upon insertion of the flexible pipe, and when the compressed state of the elastic member is released, the sealing member slides toward the inlet side of the joint body, and this sliding engages the claws of the retainer, and is characterized in that, at the time when the compressed state of the elastic member is released, the axial position of the tip of the claw on the innermost side of the joint body overlaps with the axial region between the deepest part of a predetermined valley that is to be engaged with the flexible pipe and the apex of the peak that is adjacent to the predetermined valley on the opposite side of the tip of the flexible pipe.

[0012] In this specification, based on the normal connection operation of a flexible pipe, the point at which the flexible pipe hits the back side of the fitting body straight is described as the point at which the compressed state of the elastic member is released.

[0013] Furthermore, in an aspect where "the claw portion is arranged so that the axial position of the tip portion of the claw portion on the innermost side of the fitting body overlaps the axial region between the deepest part of a specified valley portion that is the engagement target of the flexible pipe and the apex of the crest portion adjacent to the specified valley portion on the opposite side of the tip of the flexible pipe," the claw portion may be arranged so that the inner diameter tip surface of the claw portion is included within the above-mentioned axial region.

[0014] In the present invention, the release mechanism is a mechanism that includes a movable member that can move toward the rear of the joint body when a flexible pipe is inserted, and the compressed state of the elastic member is released as the movable member moves toward the rear of the joint body.The movable member has a flange portion that abuts against the joint body, and a cylindrical abutment portion that extends axially from the flange portion and against which the tip of the flexible pipe abuts, and it is preferable that the axial length of the abutment portion is longer than the axial length of the flange portion.

[0015] In the present invention, the inner diameter edge of the end face of the contact portion does not necessarily have to have an inclined surface.

[0016] In the present invention, the elastic member is preferably a cylindrical coil spring formed by winding a wire in a spiral shape. [Effects of the Invention]

[0017] By adopting the above-described configuration, the flexible pipe coupling of the present invention can keep the claws of the retainer in the correct position not only when the flexible pipe is inserted straight, but also when the flexible pipe is inserted at an angle, thereby achieving more reliable sealing performance. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a cross-sectional view of one embodiment of a pipe joint according to the present invention. [Figure 2] FIG. 2 is a perspective view showing an example of an elastic member. [Figure 3] FIG. 2 is a partially enlarged view of FIG. [Figure 4] 2A to 2C are cross-sectional views of the upper half of the pipe joint shown in FIG. 1 in various states in which a flexible pipe is inserted. [Figure 5] FIG. 4 is a partially enlarged view for explaining the operation of the pipe joint according to the present invention. [Figure 6] A cross-sectional view of the flexible pipe after installation is completed. [Figure 7] 1 is a schematic view of one embodiment of a flow path forming body according to the present invention; [Figure 8] FIG. 1 is a half-sectional view of a conventional pipe joint. [Figure 9] 9A to 9C are cross-sectional views of the upper half of the pipe joint shown in FIG. 8 in various states in which a flexible pipe is inserted. [Figure 10] 10 is a cross-sectional view showing a state in which the claw portions of the retainer are also accommodated in valley portions other than the valley portions to be engaged. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0019] One embodiment of a pipe fitting according to the present invention will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view of a pipe fitting 1. A flexible pipe T (see Fig. 4) is connected to one end (left side of the figure) of the pipe fitting 1 in Fig. 1, and a gas workpiece such as a gas valve is connected to the other end (right side of the figure). In the present invention, the direction along the central axis O of the pipe fitting 1 is referred to as the axial direction, the direction perpendicular to the central axis O in a plan view seen from the axial direction is referred to as the radial direction, and the direction going around the central axis O in the plan view is referred to as the circumferential direction.

[0020] FIG. 1 shows the state before the flexible pipe T is inserted. As shown in FIG. 1, the pipe fitting 1 includes a cylindrical fitting body 2, a press nut 3, a portion of which is inserted into the fitting body 2, an elastic member 4 that is axially expandable and contractible, a release mechanism 5 that holds the elastic member 4 in a compressed state and releases the compressed state of the elastic member 4 when the flexible pipe T is inserted, a ring-shaped seal member 6 that fits tightly against the flexible pipe T, a retainer 7, and a release member 8 that releases the state in which the press nut 3 is fixed to the fitting body 2. In FIG. 1, the release mechanism 5 includes a holding member 51 that holds the elastic member 4 in a compressed state and a moving member 52. The pipe fitting 1 is further equipped with a fireproof packing 9a, a stop ring 9b, an O-ring 9c for sealing the press nut 3 to the fitting body 2, a lip packing 9d for sealing the press nut 3 to the flexible pipe T, and a selectively permeable member 9e.

[0021] The joint body 2 has an inner bore 21 at one end into which the flexible pipe T is inserted, and an external thread portion 27 on the outer circumferential surface of the other end. The inner diameter of the inner bore 21 decreases in stages toward the other end, and a first step portion 24 and a second step portion 25 are formed. An inner circumferential groove 26 is formed between the first step portion 24 and the second step portion 25, with which the claw portion 512 of the retaining member 51 engages. In addition, inner circumferential grooves 22 and 23 are formed on the inner circumferential surface of one end of the joint body 2.

[0022] The press nut 3 is a cylindrical metal member with a through hole. The press nut 3 abuts against the retainer 7 and has a tip portion with an inclined surface 31. The outer circumferential surface of the press nut 3 is formed with an outer circumferential groove 32 into which part of the stop ring 9b enters. An O-ring 9c and a lip packing 9d are fitted in the other groove portions of the press nut 3, respectively.

[0023] The elastic member 4 is a member that can expand and contract in the axial direction. An example of an elastic member is shown in FIG. 2. As shown in FIG. 2, the elastic member 4 is a cylindrical coil spring in which wire 41 (e.g., stainless steel) is wound in a spiral shape. In the pipe fitting 1, the elastic member 4 is compressed and its spring force (reaction force) is utilized. For example, if a flexible pipe is inserted at an angle and the elastic member expands unevenly, there is a concern that a state such as 2 / 3 groove engagement may occur. However, even with this type of elastic member 4, such a state can be prevented by using the configuration described below.

[0024] 1, before the flexible pipe T is inserted, the elastic member 4 is held in a compressed state inside the joint body 2 by a release mechanism 5. This release mechanism 5 will be described with reference to the enlarged view of FIG.

[0025] As shown in FIG. 3 , the holding member 51 of the release mechanism 5 is a metal ring-shaped member having an L-shaped cross section. The holding member 51 has a support portion 511 at one end that supports the elastic member 4 and a claw portion 512 at the other end. The claw portion 512 is formed by bending the end of a circular arc plate portion 513 that extends substantially axially from the inner diameter edge of the hollow, disk-shaped support portion 511 radially outward. The holding member 51 holds the elastic member 4 in a compressed state between the support portion 511 and the first step portion 24 of the joint body 2, and the claw portion 512 is engaged with the inner circumferential groove 26 formed on the inner circumferential surface of the joint body 2. Furthermore, the inner circumferential surface of the holding member 51 is supported by a moving member 52 to prevent the engagement of the claw portion 512 from being released, thereby maintaining the elastic member 4 in a compressed state.

[0026] The moving member 52 is a member that can move toward the back of the joint body 2 when the flexible pipe T is inserted, and is arranged on the inner diameter side of the holding member 51. The moving member 52 is made of a lightweight material such as engineering plastic, allowing for smooth movement. The moving member 52 has a flange portion 521 that supports the holding member 51, and a cylindrical abutment portion 522 that extends axially from the flange portion 521 and against which the tip of the flexible pipe T abuts.

[0027] As will be described later, in the pipe fitting 1, the positions of the tip ends 711a (see FIG. 1) of the claw portions 71 of the retainer 7 on the far side of the fitting body 2 are set at the time when the compressed state of the elastic member 4 is released so that all of the claw portions 71 of the retainer 7 are accommodated in the appropriate valley portions of the flexible pipe T, even when the flexible pipe T is inserted at an angle. To achieve this configuration, in the pipe fitting 1, the axial length L2 of the abutting portion 522 of the moving member 52 is set shorter than the corresponding axial length of the moving member of a conventional pipe fitting. Setting the axial length L2 of the abutting portion 522 to be shorter makes it easier to position the tip ends 711a of the claw portions 71 of the retainer 7 at the desired position relative to the flexible pipe T.

[0028] Furthermore, because the axial length L2 of the abutting portion 522 of the moving member 52 is shortened, it becomes necessary to insert the flexible pipe T deeper into the pipe joint when connecting. As a result, the insertion amount of the flexible pipe T into the pipe joint 1 increases, making it easier to correct the insertion angle of the flexible pipe T.

[0029] In the moving member 52, it is preferable that the axial length L2 of the abutting portion 522 is longer than the axial length L1 of the flange portion 521. In Fig. 3, the axial length L2 of the abutting portion 522 is shorter than usual, but is set so as to overlap with the seal body 61 of the seal member 6 in the axial direction. In addition, the tip surface of the abutting portion 522 may be an annular flat surface; for example, in Fig. 3, an inclined surface is not formed on the inner diameter edge 522a of the tip surface of the abutting portion 522.

[0030] As specific numerical values, in the case of a size 20A pipe fitting, the axial length L2 of the abutting portion 522 is, for example, 6.0 mm to 8.0 mm, and the axial length L1 of the flange portion 521 is, for example, 2.5 mm to 3.5 mm. Also, the ratio of the axial length L1 to the axial length L2 (L1 / L2) is, for example, 0.40 to 0.60.

[0031] As shown in FIG. 3, the seal member 6 comprises a seal body 61 made of a rubber material and a presser member 62 fixed to the end face of the seal body 61 on the inlet side of the joint body 2. The presser member 62 has an L-shaped cross section and is configured to hold the fireproof packing 9a. The seal body 61 has a cylindrical inner periphery that comes into close contact with the flexible pipe, and has an inner diameter that is slightly smaller than the outer diameter of the ridges of the flexible pipe. The seal body 61 is long enough to seal two ridges of the flexible pipe. As the rubber material used for the seal body 61 must maintain sealing performance for a long period of time, nitrile butadiene rubber (NBR) is preferred in consideration of its gas resistance.

[0032] Returning to Figure 1, the other components will now be described. The retainer 7 is made of an elastically deformable material (for example, engineering plastic), and is a ring-shaped member having a base 73 on which is formed an inclined surface 72 that abuts against the press nut 3. One end of the retainer 7 is divided into a plurality of segments by a plurality of axial grooves 74 formed in the circumferential direction, and a claw portion 71 is formed on the inner diameter side of the tip of each segment. The claw portion 71 is made of a metal material (for example, brass), and is arranged with the inner diameter tip surface 711 facing radially inward.

[0033] The fireproof packing 9a is a component that prevents gas leakage even when the pipe fitting 1 is exposed to high temperatures due to a fire or the like. The fireproof packing 9a is manufactured, for example, by kneading raw rubber, a graphite intercalation compound that thermally expands in an unfoamed state, and optionally a filler, softener, vulcanizing agent, etc. to obtain a rubber composition, filling the resulting mixture into a mold, molding the mixture, and then press-vulcanizing the mixture. The fireproof packing 9a thermally expands during a fire and fills the gap between the fitting body 2 and the flexible pipe T, thereby sealing the inner surface of the fitting body 2 and the outer surface of the flexible pipe T. In FIG. 1, the fireproof packing 9a has a rectangular cross section.

[0034] The stop ring 9b is a C-shaped member formed from a wire made of a springy metal material. As shown in FIG. 1, a portion of the stop ring 9b is fitted into the inner circumferential groove 22 of the fitting body 2, and the remaining portion is fitted into the outer circumferential groove 32 of the press nut 3, thereby fixing the fitting body 2 and the press nut 3 together. The O-ring 9c is fitted into an outer circumferential groove formed on the inlet side of the fitting body 2 relative to the outer circumferential groove 32 of the press nut 3. The O-ring 9c prevents water from entering the pipe fitting 1 from the outside, thereby providing watertightness to the pipe fitting 1. The lip packing 9d is an annular member with a substantially L-shaped cross section and is fitted into the inner circumferential groove of the press nut 3. The lip packing 9d provides a watertight seal between the outer circumferential surface of the flexible pipe T and the inner circumferential surface of the press nut 3. The selectively permeable member 9e is attached to a through-hole (e.g., a circular hole) provided in the press nut 3 opposite one end of the fitting body 2 and communicating with the outside air. The selectively permeable member 9e is a porous member that allows gas to pass through but not liquid, and is provided to allow the leaked gas to pass through in the event of a gas leak from the flexible pipe T so that it can be detected by an external gas sensor or the like.

[0035] The release member 8 is a ring-shaped member with a substantially L-shaped cross section. The end of the release member 8 on the inlet side of the joint body 2 is formed so that the cross section tapers toward the tip. The release member 8 is attached adjacent to the seal member 6 and so that its body is in contact with the inner circumferential surface of the joint body 2. When the seal member 6 slides due to the stretching force of the elastic member 4, the release member 8 slides toward the inlet side of the joint body 2 together with the seal member 6. As a result of this sliding, the end of the release member 8 on the inlet side of the joint body 2 enters between the inner circumferential groove 22 and the stop ring 9b, causing the stop ring 9b to contract in diameter and releasing the press nut 3 from being fixed to the joint body 2.

[0036] Next, the insertion operation of the flexible pipe T will be described with reference to FIG. 4. FIG. 4 shows upper half cross-sectional views of various states in which the flexible pipe is inserted straight into the pipe fitting of FIG. 1. Here, the flexible pipe T is a corrugated metal pipe (e.g., a stainless steel pipe) with multiple peaks and valleys alternately arranged along the axial direction. Typically, the tip Ta of the flexible pipe T is cut so that it is perpendicular to the axial direction at the deepest position of the valleys. The flexible pipe T is inserted into the pipe fitting 1 after several peaks (six peaks in FIG. 4) of the outer coating resin are removed from the tip Ta. In FIG. 4, the third valley v3 from the tip Ta is the valley to be engaged.

[0037] First, the flexible pipe T is inserted into one end of the pipe fitting 1 and passes through the inner periphery of the press nut 3 and the retainer 7, and the tip Ta of the flexible pipe T abuts against the tip surface of the abutting portion 522 of the moving member 52 (see FIG. 4(a)). As described above, the axial length of the abutting portion 522 of the moving member 52 is shorter than usual, and in the state of FIG. 4(a) (and the state of FIG. 4(b) as well), the flexible pipe T is inserted into the pipe fitting by that amount. The moving member 52 moves further toward the inner side of the fitting body 2 in response to the insertion of the flexible pipe T. Then, as the moving member 52 moves, the claws 512 of the holding member 51 come out of the inner circumferential groove 26 of the fitting body 2, the compressed state of the elastic member 4 is released, and the flexible pipe T abuts against the inner side of the fitting body 2. FIG. 4(b) shows the state at this point. Specifically, the flange portion 521 of the moving member 52 abuts against a wall surface (the second step portion 25 of the joint body 2 in FIG. 4(b)), causing the flexible pipe T to abut against the inner side of the joint body 2.

[0038] In the present invention, the positional relationship between the claw portion 71 of the retainer 7 and the valley portion v3 of the flexible pipe T that is to be engaged is set at the time when the compressed state of the elastic member 4 is released (in FIG. 4, this is the time when the flexible pipe T hits the back side of the fitting body 2). This positional relationship will be explained using FIG. 5. The upper diagram in FIG. 5 shows an enlarged view of the area around the retainer at the above-mentioned time. Note that part A, partially indicated by a dotted line, indicates the claw portion of the retainer in a conventional pipe fitting.

[0039] First, in conventional pipe fittings, the deepest portion of the valley portion v3 to be engaged and the inner diameter surface of the tip of the claw portion A are arranged to overlap in the axial direction, and the axial position of the tip of the claw portion A on the innermost side of the fitting body 2 is located closer to the tip of the flexible pipe T than the deepest portion of the valley portion v3. In this configuration, if the flexible pipe T is inserted at an angle, for example, the seal member 6 will slide with its slide axis tilted relative to the central axis of the flexible pipe T, which could result in some of the multiple claws of the retainer 7 fitting into the valley portion v3 to be engaged and the rest fitting into the valley portion v2 to be engaged. In other words, if the valley portion to be engaged is the nth valley portion from the tip Ta of the flexible pipe T, the claws will fit into the n-1th valley portion and the nth valley portion (n-1 / n valley engagement). Furthermore, as shown in FIG. 10 , if further external bending force is applied from this state, the interference with the seal member will be reduced, potentially making it impossible to obtain sufficient sealing performance.

[0040] In contrast, in the pipe fitting of the present invention, in consideration of the above-described n-1 / n valley engagement phenomenon, the positions of the claws 71 are shifted toward the opposite side of the tip of the flexible pipe T from conventional ones so that all of the claws 71 of the retainer 7 can fit into the valleys of the flexible pipe to be engaged, even when the flexible pipe T is inserted at an angle. Specifically, as shown in the upper diagram of FIG. 5 , at the time when the compressed state of the elastic member 4 is released, the claws 71 are provided so that the axial position P of the tip ends 711 a of the claws 71 overlaps with the axial region R between the deepest part of the valley to be engaged (the nth valley; v3 in FIG. 5 ) and the apex of the peak adjacent to that valley on the opposite side of the flexible pipe T (the n+1th peak from the tip Ta of the flexible pipe T; the fourth peak from the tip Ta in FIG. 5 ). In other words, the positional relationship is such that the axial position P of the tip ends 711 a of the claws 71 is included within the axial region R.

[0041] In Figure 5, when the compressed state of the elastic member 4 is released, the elastic member 4 expands, and the expansion force causes the seal member 6 to slide toward the inlet side of the fitting body 2. At this time, the flexible pipe T, which is in close contact with the seal member 6, also slides along with the seal member 6 as shown by the black arrow. The retainer 7 is then pushed by the release member 8, and the inclined surface 72 comes into close contact with the inclined surface of the press nut 3, and the claw portion 71 rotates to reduce its diameter and fit into the valley portion v3 of the flexible pipe T (see the lower diagram in Figure 5). In the present invention, the axial position P of the tip end 711a of the claw portion 71 is particularly specified in consideration of this diameter-reducing movement of the claw portion 71 of the retainer 7.

[0042] Furthermore, the claw portion 71 may be provided such that the entire inner diameter tip surface 711 (including the tip portion 711a) of the claw portion 71 is included within the axial region R. By adopting such a positional relationship, the claw portion 71 can be easily accommodated in the same valley portion (valley portion v3 in FIG. 5) over the entire circumference.

[0043] In the pipe fitting of the present invention, by establishing the above-described positional relationship when the flexible pipe T is inserted straight to the back and the compressed state of the elastic member 4 is released, even if, for example, the flexible pipe is inserted at an angle at an actual flexible pipe connection work site, causing the sealing member 6 to slide while tilted relative to the central axis of the flexible pipe T and causing some variation in the diameter-reducing action among the multiple claws, all of the claws can be reduced in diameter between the apexes of the crests on both sides adjacent to the valleys with which they engage. As a result, all of the claws can be fitted into the valleys with which they engage.

[0044] After the claws 71 of the retainer 7 are engaged, the installer performs a checking operation by pulling the flexible pipe T. As a result, the state shown in FIG.

[0045] In the state shown in FIG. 6 , the fitting body 2 and the press nut 3 are mechanically coupled to prevent relative movement therebetween. Therefore, even if further pulling force is applied to the flexible pipe T, the flexible pipe T cannot come out of the pipe fitting 1, and it is determined that installation of the flexible pipe T is complete. Also, in FIG. 6 , a gap is formed between the end face of the fitting body 2 and the press nut 3, and a portion of the press nut 3 (e.g., the outer surface of the small diameter portion) that was hidden inside the fitting body 2 appears in the gap. In FIG. 6 , this portion of the press nut 3 is colored, and a colored portion 33 appears at the end of the fitting body 2 upon completion of installation. In the pipe fitting 1, the colored portion 33 can function as an indicator. By checking this indicator, it is possible to confirm that the flexible pipe T is properly connected and determine that installation has been completed successfully.

[0046] The pipe joint of the present invention is not limited to the configuration described above with reference to FIGS.

[0047] In the embodiment described above, the pipe joint 1 is configured to include the release member 8, but this release member 8 may be omitted. Furthermore, the release mechanism 5 need not be a mechanism composed of the holding member 51 and the moving member 52, as long as it holds the elastic member 4 in a compressed state and releases the compressed state of the elastic member 4 by inserting the flexible pipe T. Furthermore, the elastic member 4 may be a member that is expandable and contractible in the axial direction, such as a leaf spring.

[0048] The flow path forming member of the present invention includes a bellows-shaped flexible pipe that forms a part of a fluid flow path and has a plurality of peaks and valleys alternately arranged along the axial direction, and a flexible pipe joint to which the flexible pipe is connected. The pipe joint in this flow path forming member can be any of the pipe joints of the present invention described above.

[0049] As described above, the pipe fitting of the present invention can prevent the n-1 / n valley engagement phenomenon. Furthermore, the pipe fitting can maintain its sealing performance even when the flexible pipe T connected to the pipe fitting is bent in the vicinity of the opening of the pipe fitting. Therefore, as shown in FIG. 7, the pipe fitting can be suitably used as a flow path forming member in which the flexible pipe T is bent near the opening of the pipe fitting 1 and connected. In this state, an external bending force is applied to the connected flexible pipe T.

[0050] The present invention also relates to a method for setting the axial length of the abutting portion of the moving member in the above-mentioned pipe joint so that the axial position of the tip end portion of the claw portion of the retainer on the inner side of the joint body is located at a desired position with respect to the flexible pipe T. For example, this is a method for setting the axial length of the abutting portion of the moving member so that the axial length L2 of the abutting portion of the moving member is greater than the axial length L1 (L2>L1), and so that the axial position of the tip end portion of the claw portion of the retainer on the inner side of the joint body overlaps the axial region between the deepest part of a predetermined valley portion that is to engage with the flexible pipe and the apex of the crest portion that is adjacent to the predetermined valley portion on the opposite side of the tip of the flexible pipe. [Explanation of symbols]

[0051] 1: Pipe fittings (flexible pipe fittings) 2: Fitting body 21: Inner hole 22: Inner groove 23: Inner groove 24: First stage 25: Second stage 26: Inner groove 27: Male thread 3: Press nut 31: Inclined surface 32: Peripheral groove 33: Colored part 4: Elastic member 41:Wire rod 5:Release mechanism 51: Holding member 511: Support part 512: Claw part 513: Arc plate section 52: Moving parts 521: Flange part 522: Contact part 6: Sealing material 61: Seal body 62: Pressing member 7: Retainer 71: Claw part 711: Inner diameter tip surface 711a:Tip 72: Inclined surface 73: Base 74: Axial groove 8: Release member 9a: Fireproof packing 9b: Stop ring 9c: O-ring 9d: Lip packing 9e: Selectively permeable material T: Flexible pipe Ta: Tip v1~v3: Tanibe

Claims

1. A flexible pipe joint for connecting a bellows-shaped flexible pipe having a plurality of peaks and valleys alternately arranged along an axial direction, The flexible pipe joint includes a joint body into which the flexible pipe is inserted from one end, and includes, inside the joint body, a retainer having a plurality of claw portions that engage with the flexible pipe, a ring-shaped seal member that comes into close contact with the flexible pipe, an elastic member that is held in a compressed state, and a release mechanism that holds the elastic member in a compressed state and releases the compressed state of the elastic member when the flexible pipe is inserted, and when the compressed state of the elastic member is released, the seal member slides toward the inlet side of the joint body, and this sliding engages the claw portions of the retainer, a flexible pipe coupling, characterized in that, at the time when the compressed state of the elastic member is released, the axial position of the tip of the claw portion on the rear side of the coupling body overlaps the axial region between the deepest part of a specified valley portion that is the engagement target of the flexible pipe and the apex of the crest portion adjacent to the specified valley portion on the opposite side of the tip of the flexible pipe.

2. 2. The flexible pipe coupling according to claim 1, wherein the claw portion is arranged so that the inner diameter tip surface of the claw portion is included within the axial region when the compressed state of the elastic member is released.

3. the release mechanism includes a movable member that is movable toward the inner side of the joint body upon insertion of the flexible pipe, and the compressed state of the elastic member is released by the movable member moving toward the inner side of the joint body, 3. A flexible pipe joint as described in claim 1 or claim 2, characterized in that the moving member has a flange portion that abuts against the joint body and a cylindrical abutment portion that extends axially from the flange portion and against which the tip of the flexible pipe abuts, and the axial length of the abutment portion is longer than the axial length of the flange portion.

4. 4. A flexible pipe joint according to claim 3, wherein the inner diameter edge of the end face of said abutting portion is not formed with an inclined surface.

5. 3. A flexible pipe joint according to claim 1, wherein the elastic member is a cylindrical coil spring made of a wire wound in a spiral shape.

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