Flexible Pipe Fittings

Abstract

To provide a joint for a flexible pipe capable of saving resources while keeping high sealability.SOLUTION: A pipe joint 1 for connecting a bellows-like flexible pipe on which a plurality of crest portions and trough portions are alternately arranged along an axial direction, includes a joint body 2 to which the flexible pipe is inserted from one end portion, and a retainer 8 having claw portions 81 engaged with the trough portions of the flexible pipe, an elastic member 4 held in a compressed state, and a ring-like seal body 71 sliding toward one end portion of the joint body 2 by releasing the compressed state of the elastic member 4 by insertion of the flexible pipe so as to be compressed and closely kept into contact with the flexible pipe, are disposed inside of the joint body 2. Shore A hardness of the seal body 71 is 20-45, and the seal body 71 is closely kept into contact with a slant face at least at a tip side of the first crest portion from the tip of the flexible pipe in a connection state with the flexible pipe.SELECTED DRAWING: Figure 1

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. In addition, various pipe joints are used to connect the flexible pipes to gas valves, steel pipes, etc. In recent years, one-touch pipe joints have been put into practical use, which do not require tools and can be installed by simply inserting the flexible pipe into the pipe joint.

[0003] For example, a flexible pipe joint (hereinafter simply referred to as a pipe joint) described in Patent Document 1 is shown in Figures 15 and 16. Figure 15 shows the state before the flexible pipe is inserted, and Figure 16 shows the state after the flexible pipe is connected. As shown in Figure 15, the pipe joint 11 has a joint body 12 into which a flexible pipe T (see Figure 16) is inserted from one end, and inside the joint body 12, a part of a press nut 13, a retainer 18 (a retaining member), an elastic member 14 that is expandable and contractible in the axial direction, a holding member 15 that holds the elastic member 14 in a compressed state, a moving member 16, and a ring-shaped seal member 17 that comes into close contact with the outer circumferential surface of the flexible pipe T are arranged.

[0004] As shown in FIG. 16, when a bellows-shaped flexible pipe T is inserted into this pipe joint, the engagement between the holding member 15 and the joint body 12 is released, and the compressed state of the elastic member 14 is released. Then, as the elastic member 14 expands, the seal member 17 slides and is compressed in the axial direction. This brings the seal member 17 into close contact with the outer circumferential surface of the flexible pipe T. Note that a rubber member with a Shore A hardness of about 50 is used for the seal body 17a of the seal member 17. Also, as the elastic member 14 expands, the retainer 18 contracts in diameter and the claw portions 18a fit into the valleys of the flexible pipe T. This causes the retainer 18 to catch on the outer circumferential surface of the flexible pipe T, preventing the flexible pipe T from coming loose. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2011-52762 A Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, a pipe fitting is connected by inserting a flexible pipe into the inner hole of the pipe fitting. As shown in Fig. 16, a conventional pipe fitting 11 maintains a sealing performance by ensuring a sufficient contact area with the flexible pipe T. However, it is necessary to insert a considerable amount of the flexible pipe into the inner hole of the pipe fitting, and it is believed that there is room for improvement from the viewpoint of saving resources such as pipe fittings and flexible pipes.

[0007] The present invention has been made in consideration of the above circumstances, and has an object to provide a flexible pipe joint that can achieve resource conservation while maintaining good sealing properties. [Means for solving the problem]

[0008] 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 alternately arranged along the axial direction, and includes a joint body into which the flexible pipe is inserted from one end, and includes a retainer having a claw portion that fits into the valley portion of the flexible pipe, an elastic member held in a compressed state, and a ring-shaped seal member that slides toward one end of the joint body and is compressed by the insertion of the flexible pipe and is in close contact with the flexible pipe when the compressed state of the elastic member is released, and has a Shore A hardness of 20 to 45, and the seal member is in close contact with at least the slope of the tip side of the first peak from the tip of the flexible pipe when connected to the flexible pipe. In the present invention, "in close contact" with the flexible pipe means a state in which the seal member is pressed against the flexible pipe over the entire circumference and in contact with the flexible pipe without any gaps. The seal member can reliably seal the fluid inside by being in close contact with the flexible pipe.

[0009] In the present invention, the seal member preferably has a convex portion protruding in the radially reducing direction on the inner periphery of the seal member, which is in close contact with the flexible pipe, on the rear side of the joint body before the seal member is compressed.

[0010] Furthermore, in the present invention, it is more preferable that the seal member has a ring-shaped seal body made of a rubber material and an annular pressing member fixed to the end face of the seal body on the inlet side of the joint body, and that the inner peripheral portion of the seal body is exposed to the inlet side of the joint body.

[0011] In the present invention, the seal member may be one that adheres closely to only the first peak.

[0012] In addition, in the present invention, the retainer may be positioned in a state in which the inner diameter of the claw portion is smaller than the outer diameter of the ridge portion of the flexible pipe before the flexible pipe is inserted, and the claw portion may climb over the ridge portion of the flexible pipe when the flexible pipe is inserted.

[0013] In the present invention, in a connected state with a flexible pipe, one or more ridges may be interposed between the ridges with which the seal member is in close contact and the tabs of the retainer. Effect of the Invention

[0014] The flexible pipe joint of the present invention has a retainer, an elastic member held in a compressed state, and a ring-shaped seal member that slides toward one end of the joint body and is compressed to fit closely to the flexible pipe when the elastic member is released from its compressed state by inserting the flexible pipe. The seal member has a Shore A hardness of 20 to 45, and when connected to the flexible pipe, the seal member fits closely to at least the slope of the first crest from the tip of the flexible pipe, so that the flexible pipe can be sealed closer to the tip side than the seal member of a conventional flexible pipe joint. As a result, the axial length of the pipe joint and the length of the flexible pipe inserted into the pipe joint during connection can be shortened, and resource saving can be achieved. In addition, the seal member of the flexible pipe joint of the present invention has a lower hardness than the conventional seal member, so that it can easily follow the shape of the crest of the flexible pipe and maintain sealing properties. [Brief description of the drawings]

[0015] [Figure 1] 1 is a half-sectional view of a first embodiment of a pipe joint according to the present invention. [Diagram 2] 2 is a plan view of the retainer of FIG. 1; [Diagram 3] 2 is a half-sectional view of the sealing member of FIG. 1. [Figure 4] 13A to 13C are diagrams for explaining the insertion operation of a flexible tube. [Diagram 5] 2 is a half-sectional view of the pipe joint of FIG. 1 in a state where a flexible pipe is connected. FIG. [Figure 6] FIG. 4 is a half-sectional view of a second embodiment of a pipe joint according to the present invention. [Figure 7] FIG. 7 is a half-sectional view of the pipe joint of FIG. 6 in a state where a flexible pipe is connected. [Figure 8] 7 is a half-sectional view of the sealing member of FIG. 6. [Figure 9] FIG. 11 is a half-sectional view of a third embodiment of a pipe joint according to the present invention. [Figure 10] 10 is a half-sectional view showing a state in which a flexible pipe is being inserted into the pipe joint of FIG. 9. FIG. [Figure 11] 10 is a half-sectional view of the pipe joint of FIG. 9 in a state where a flexible pipe is connected. [Figure 12] FIG. 1 is a diagram for explaining an outline of a tensile test using a pipe joint. [Figure 13] FIG. 1 is a diagram for explaining an outline of a root bending test using a pipe joint. [Figure 14] 1 is a cross-sectional photograph of a pipe joint in a connected state to a flexible pipe. [Figure 15] FIG. 1 is a half-sectional view of a conventional pipe joint. [Figure 16] 16 is a half-sectional view of the pipe joint of FIG. 15 in a state where a flexible pipe is connected thereto. [Figure 17] FIG. 16 is a half-sectional view of the seal member of FIG. 15. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] (First embodiment) A first embodiment of a pipe fitting according to the present invention will be described with reference to Fig. 1. Fig. 1 is a half-side cross-sectional view of the pipe fitting, with the upper half above the central axis O of the pipe fitting 1 being a cross-sectional view and the lower half being a side view. 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 another pipe, gas equipment, etc. is connected to the other end (right side of the figure).

[0017] 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 from the axial direction is referred to as the radial direction, and the direction rotating around the central axis O in the plan view is referred to as the circumferential direction.

[0018] 1, the pipe joint 1 includes a cylindrical joint body 2, a press nut 3 a part of which is inserted into the joint body 2, an elastic member 4, a holding member 5 which holds the elastic member 4 in a compressed state, a moving member 6, a ring-shaped seal member 7 which comes into close contact with the flexible pipe T, and a retainer 8 having a claw portion 81 which fits into a valley portion T2 (see FIG. 4) of the flexible pipe T. Also, the pipe joint 1 is equipped with a fireproof packing 9a, a stop ring 9b, an O-ring 9c for sealing the press nut 3 to the joint body 2, a lip packing 9d for sealing the press nut 3 to the flexible pipe T, and a selectively permeable member 9e.

[0019] The joint body 2 has an inner hole 21 at one end into which the flexible pipe T is inserted, and a male thread portion 27 on the outer circumferential surface of the other end. The inner diameter of the inner hole 21 decreases stepwise toward the other end, and a first step portion 24 and a second step portion 25 are formed. An engagement groove 26 is formed between the first step portion 24 and the second step portion 25, into which one end of the retaining member 5 is engaged. In addition, inner circumferential grooves 22, 23 are formed on the inner circumferential surface of one end of the joint body 2.

[0020] The press nut 3 is a cylindrical metal member having a through hole. An outer circumferential groove 31 into which a part of the stop ring 9b enters is formed on the outer circumferential surface of the press nut 3. An O-ring 9c and a lip packing 9d are fitted in the other grooves of the press nut 3, respectively.

[0021] The elastic member 4 is a coil spring that can expand and contract in the axial direction. Before the flexible pipe T is inserted, the elastic member 4 is held in a compressed state by the holding member 5. The holding member 5 is a metal ring-shaped member having an L-shaped cross section with a part protruding, and has a hollow disk-shaped support part 51 at one end and a bent part 52 bent radially outward at the other end. The holding member 5 holds the elastic member 4 in a compressed state between the support part 51 and the first step part 24 of the joint body 2, and engages the bent part 52 with the engagement groove 26 of the joint body 2. Furthermore, the inner peripheral surface of the holding member 5 is supported by the moving member 6 to prevent the engagement of the bent part 52 from being released, thereby maintaining the compressed state of the elastic member 4. The moving member 6 is a substantially cylindrical member provided on the inner diameter side of the holding member 5 so as to be movable in the axial direction.

[0022] The retainer 8 is a ring-shaped member made of a metal material (e.g., stainless steel). In FIG. 1, the retainer 8 is provided so as to taper toward the back side of the joint body, and is disposed in such a state that the inner diameter of the claw portion 81 is smaller than the outer diameter of the crest portion T1 (see FIG. 4) of the flexible pipe T. The configuration of the retainer 8 will be described with reference to FIG. 2. FIG. 2(a) is a plan view of the retainer, FIG. 2(b) is a side view, and FIG. 2(c) is a perspective view. As shown in FIG. 2, the retainer 8 has a hollow disk-shaped base portion 82, a plurality of claw portions 81 extending from the base portion 82 to one side so as to taper, and a plurality of holding pieces 83 extending from the base portion 82 to the opposite side of the claw portions 81.

[0023] The claws 81 are arranged side by side in the circumferential direction and are divided by grooves cut in the axial direction. In addition, the tip of each claw 81 is divided into two claw pieces 812 by a notched groove 811. By dividing each claw 81 into two claw pieces, it becomes easier to fit into the valley portion T2 of the flexible pipe T. In addition, the base 82 is formed parallel to a plane perpendicular to the axial direction of the retainer 8.

[0024] 1, the base 82 is disposed parallel to a plane perpendicular to the axial direction of the pipe joint, and the fireproof packing 9a abuts against the base 82. In the pipe joint 1, the base 82 of the retainer 8, the fireproof packing 9a, the seal member 7, the support portion 51 of the holding member 5, and the elastic member 4 are disposed in a straight line along the axial direction, so that the restoring force of the elastic member 4 can be efficiently transmitted to the retainer 8. As a result, the seal member 7 can be compressed stably, and the claw portions 81 of the retainer 8 can be fitted into the valley portions to stably hook the retainer 8 onto the flexible pipe T.

[0025] The fireproof packing 9a is a member for preventing gas leakage even when the pipe joint 1 is exposed to high temperatures due to fire or the like. The fireproof packing 9a is manufactured, for example, by kneading raw rubber, a graphite intercalation compound that expands thermally in an unfoamed state, and, if necessary, a filler, a softener, a vulcanizing agent, and the like to obtain a rubber composition, filling the rubber composition in a mold, molding the rubber composition, and then press-vulcanizing the rubber composition. The fireproof packing 9a expands thermally in the event of a fire, and fills the gap between the joint body 2 and the flexible pipe T, thereby sealing the outer circumferential surface of the flexible pipe T. In FIG. 1, the fireproof packing 9a has a rectangular cross section.

[0026] The stop ring 9b is a C-shaped member formed of a wire made of a metal material having spring properties. As shown in FIG. 1, a part of the stop ring 9b is fitted into the inner circumferential groove 22 of the joint body 2, and the other part is fitted into the outer circumferential groove 31 of the press nut 3, thereby fixing the joint body 2 and the press nut 3. When the press nut 3 is inserted into the joint body 2 with the stop ring 9b fitted into the outer circumferential groove 31 of the press nut 3, the stop ring 9b is once expanded in diameter at the inner circumferential groove 23. As the insertion proceeds further, the stop ring 9b is guided by the inclined surface of the circumferential groove 23 to reach the circumferential groove 22, where it is expanded in diameter to fix the press nut 3.

[0027] The O-ring 9c is fitted into an outer circumferential groove formed on the inlet side of the joint body relative to the outer circumferential groove 31 of the press nut 3. The O-ring 9c prevents water from entering the inside of the pipe joint 1 from the outside, and provides watertightness to the pipe joint 1. The lip packing 9d is an annular member having 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.

[0028] The selectively permeable member 9e is attached to a through hole (e.g., a circular hole) that is provided in the press nut 3 at a position facing one end of the joint body 2 and communicates with the outside air. The selectively permeable member 9e is a porous member that is permeable to gas but not to 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 the leaked gas can be detected by an external gas sensor or the like.

[0029] Next, the configuration of the seal member of the pipe joint will be described. First, a seal member in a conventional pipe joint is shown in Fig. 17. Fig. 17(a) is a half-sectional view of the conventional seal member, and Fig. 17(b) is its plan view.

[0030] As shown in Fig. 17, the seal member 17 has a seal body 17a made of a rubber material, and a pressing member 17b fixed to the end face of the seal body 17a on the inlet side of the joint body. The pressing member 17b has an L-shaped cross section and is configured to hold a fireproof packing 19a (see Fig. 15). The seal body 17a has a cylindrical inner periphery that comes into close contact with the flexible pipe T, and has an inner diameter that is slightly smaller than the outer diameter of the crest T1 of the flexible pipe T. The seal body 17a has a Shore A hardness of about 50, and is long enough to seal two crests of the flexible pipe T.

[0031] Next, FIG. 3 shows a seal member in the pipe joint of the present invention. FIG. 3(a) is a half-side cross-sectional view of the seal member according to the present invention, FIG. 3(b) is an enlarged view of the X portion, and FIG. 3(c) is a plan view. As shown in FIGS. 3(a) and 3(b), the seal member 7 has a seal body 71 made of a rubber material and a ring-shaped pressing member 72 fixed to the end face of the seal body 71 on the inlet side of the joint body. The ring shape in the present invention also includes a form in which a part of the ring is cut out. The pressing member 72 is in the shape of a ring flat plate and is formed from a metal material. For example, the seal member 7 is obtained by insert molding a rubber material in a mold in which the pressing member 72 is arranged. The pressing member 72 may be fixed by adhering to the seal body 71 molded separately.

[0032] As shown in FIG. 3(b), the inner periphery 711 of the seal body 71 is exposed to the inlet side of the joint body. In other words, the pressing member 72 does not cover the entire inlet side of the joint body of the seal body 71, and the inner periphery 711 of the seal body 71 is not constrained by the pressing member 72 and other peripheral members (joint body 2 and holding member 5) in the pre-compression state shown in FIG. 1. As a result, when the seal body 71 is compressed between the pressing member 72 and the elastic member, the inner periphery 711 of the seal body 71 is deformed, and a part of the inner periphery 711 protrudes toward the inlet side of the joint body (see FIG. 5 and FIG. 14 described later). This makes it easier to come into close contact with the slope on the side opposite to the tip of the first crest from the tip of the flexible pipe T, improving the sealing performance. In FIG. 3(b), the inner periphery 711 of the seal body 71 is a portion including the convex portion 712 and the insertion taper portion 714 formed at the end of the inlet side of the joint body.

[0033] As shown in FIG. 3(b), the seal body 71 has a convex portion 712 protruding in the direction of diameter reduction on the inner circumferential portion 711 of the seal body that is in close contact with the flexible pipe T at the rear side of the joint body in an unloaded state (before compression). The height H of the convex portion 712 is preferably 0.2 mm or more from the viewpoint of sealing performance, and is preferably in the range of 0.2 mm to 1.0 mm. The seal body 71 has an inner diameter that is slightly smaller than the outer diameter of the crest of the flexible pipe T at the cylindrical portion of the inner circumferential portion 711, and has an even smaller inner diameter at the convex portion 712. By forming the convex portion 712 in this manner, the tip of the flexible pipe T can be held, and the seal body 71 can be easily brought into close contact with the inclined surface at the tip side of the first crest portion T1. In addition, the end face of the convex portion 712 on the inlet side of the joint body is an inclined surface 713. The inclination angle of the inclined surface 713 with respect to the axial direction of the seal body 71 is preferably an angle that allows it to be in close contact with the shape of the flexible pipe T, and is, for example, 30 degrees to 60 degrees. By forming the inclined surface 713, it becomes easier to bring the flexible pipe T into close contact with the inclined surface on the tip side of the first peak portion T1.

[0034] In Fig. 3(b), the axial length L of the seal body 71 is designed to be a length capable of sealing one crest of the flexible pipe T. The axial length L varies depending on the outer diameter of the flexible pipe T, and is, for example, 3 mm to 6 mm. Also, as shown in Fig. 3(c), the ring-shaped seal body 71 and the pressing member 72 are concentrically arranged, and the outer diameter of the seal body 71 is slightly larger than the outer diameter of the pressing member 72. The outer diameter of the seal body 71 is, for example, 20 mm to 40 mm.

[0035] In the present invention, the seal body 71 is made of a rubber material and has a Shore A hardness of 20 to 45. The Shore A hardness is a type A durometer hardness, and is a value determined by a method defined in Japanese Industrial Standard JIS K 6253-3. The Shore A hardness of the seal body 71 is preferably 20 to 40, and more preferably 20 to 30. In addition, as the rubber material used for the seal body 71, nitrile butadiene rubber (NBR) is preferable in consideration of gas resistance, since it is necessary to maintain sealing performance for a long period of time.

[0036] The insertion operation of the flexible pipe will be described with reference to Fig. 4. As shown in Fig. 4, the flexible pipe T is a bellows-shaped metal pipe (e.g., a stainless steel pipe) in which multiple peaks T1 and valleys T2 are alternately arranged along the axial direction. Usually, the tip T3 of the flexible pipe T is cut at a right angle to the axial direction at the position of the valleys T2. The flexible pipe T is inserted into the pipe fitting 1 after several peaks (e.g., 4 to 7 peaks) of the outer coating resin are removed from the tip T3.

[0037] The flexible pipe T is inserted from one end of the pipe joint 1, and passes through the press nut 3 and the inner periphery of the retainer 8. As described above, the inner diameter of the claw portion 81 of the retainer 8 is arranged to be smaller than the outer diameter φ of the crest portion T1 of the flexible pipe T. Therefore, the claw portion 81 operates to climb over the crest portion T1 of the flexible pipe T. Specifically, the claw portion 81 moves to expand in diameter and the holding piece 83 moves to contract in diameter, with the abutment point between the base portion 82 and the fireproof packing 9a as a fulcrum. Then, the tip portion T3 of the flexible pipe T hits the moving member 6, and the flange portion 61 of the moving member 6 is pushed toward the second step portion 25.

[0038] When the flexible pipe T is pushed all the way in, the free end of the bent portion 52 of the holding member 5 disengages from the engagement groove 26 of the joint body 2, and the compressed state of the elastic member 4 is released, causing the elastic member 4 to expand. The expanding elastic member 4 presses the support portion 51, thereby pressing the seal body 71 toward one end of the inlet side of the joint body, causing the seal body 71 to slide and become compressed. As a result, the seal body 71 comes into close contact with the flexible pipe T, completing the insertion.

[0039] FIG. 5 shows a state where the insertion of the flexible pipe is completed (connected state). In this connected state, the seal body 71 is compressed by being sandwiched between the metal support 51 and the pressing member 72, and is in close contact with the first peak T1 from the tip T3 of the flexible pipe T. Specifically, the inner periphery of the seal body 71 is bifurcated (into two legs) so as to cover the first peak T1, and is in close contact with the slopes T1a and T1b on both sides of the peak T1. The seal body 71 has a Shore A hardness of 20 to 45, so that it is easily deformed along the shape of the peak T1, and further has a convex portion 712 (see FIG. 3(b)), so that it is easily in close contact with the slope T1a on the tip side of the peak T1. In addition, a part of the inner periphery of the seal body 71 (the leg on the inlet side of the joint body) extends into the space between the slope T1b on the opposite tip side of the peak T1 and the pressing member 72, and is in close contact with the slope T1b. This leg protrudes toward the inlet side of the joint body from the end face of the pressing member 72. Note that the claw portion 81 of the retainer 8 fits into the valley between the first and second peaks from the tip portion T3.

[0040] In the conventional pipe joint, as shown in Fig. 16, in the connected state, the tip portion T3 of the flexible pipe T passes through the seal member 17, and the outer periphery side of the flexible pipe T is sealed. In other words, the flexible pipe T is inserted through the seal member 17 to be sealed.

[0041] In contrast, in the pipe joint 1 according to the present invention, as shown in FIG. 5, the flexible pipe T is sealed at a more distal end side, and the distal end portion T3 of the flexible pipe T does not protrude from the seal member 7. As a result, the axial length of the pipe joint 1 and the length of the flexible pipe T inserted into the pipe joint at the time of connection can be shortened, and resource saving can be achieved. On the other hand, since the seal is provided at a more distal end side, the structure is such that gaps are easily generated due to the movement (bending, etc.) of the flexible pipe T. In contrast, in the pipe joint 1, the seal body 71 is made to have a Shore A hardness of 20 to 45, which is lower than the conventional hardness, so that it is easily deformed, thereby improving the followability of the seal body 71 to the movement of the flexible pipe T. As a result, the pipe joint 1 ensures a sufficient contact area for the seal, and the seal body 71 is in close contact with the flexible pipe T. Furthermore, the seal member 71 is provided with a protruding portion 712 (see FIG. 3(b)) on the inner periphery thereof to improve the sealing performance.

[0042] Furthermore, the pipe joint according to the present invention can reduce the load when inserting a flexible pipe compared to conventional pipe joints. The inner diameter of the seal body is usually slightly smaller than the outer diameter of the flexible pipe. Therefore, in a conventional structure in which the two peaks at the tip of a flexible pipe are inserted into the inner periphery of the seal body, there is a risk of the load being excessive during insertion. The present invention is also advantageous in this respect, and the reduction in the load when inserting a flexible pipe makes it possible to improve workability.

[0043] Second embodiment A pipe joint according to a second embodiment of the present invention will be described with reference to Figures 6 to 8. The same components as those in the first embodiment described with reference to Figures 1 to 5 are given the same reference numerals and detailed description will be omitted. Figure 6 shows the state before a flexible pipe is inserted, and Figure 7 shows the state after the flexible pipe is connected.

[0044] As shown in Fig. 6, the pipe fitting 1A is different from the pipe fitting of the first embodiment in the configuration of the seal member 7A. Specifically, the seal body 71 of the first embodiment is long enough to seal one ridge of the flexible pipe T, whereas the seal body 71A is long enough to seal two ridges of the flexible pipe T. The axial length L of the seal body 71A is, for example, 6 mm to 10 mm, and the seal body 71A has a convex portion 712 that protrudes in the diameter reducing direction on the rear side of the fitting body of the inner periphery 711 that comes into close contact with the flexible pipe T (see Fig. 8).

[0045] In the connected state of FIG. 7, the seal body 71A is compressed by being sandwiched between the support portion 51 and the pressing member 72, and the seal surface pressure with the flexible pipe T increases. As a result, the seal body 71A is in close contact with the first crest T1 and the second crest from the tip portion T3 of the flexible pipe T. Even in this form, the seal body 71A is in close contact with at least the slope T1a on the tip side of the first crest T1, and the tip portion T3 of the flexible pipe T does not protrude from the seal body 71A. The claw portion 81 of the retainer 8 is fitted in the valley between the second crest and the third crest from the tip portion T3.

[0046] Third embodiment However, when a pull-out force is applied to the flexible pipe in a connected state with the flexible pipe, the claw portion of the retainer may deform the contact portion of the flexible pipe in some cases. As shown in Figs. 5 and 7, the pipe joints of the first and second embodiments described above are configured such that, in a connected state with the flexible pipe T, the claw portion 81 of the retainer 8 fits into the valley portion T2 adjacent to the peak portion T1 in close contact with the seal member 7, 7A. When a pull-out force is applied to the flexible pipe in such a connected state, it is considered that the peak portion with which the claw portion 81 of the retainer 8 comes into contact (for example, the first peak portion T1 from the tip of the flexible pipe T in Fig. 5) is in contact with the claw portion 81 of the retainer 8, the claw portion 81 may bite into or be squeezed by the claw portion 81 at the contact portion, and thus the peak portion may be deformed unevenly. Such deformation of the peak portion may change the state of contact between the peak portion T1 and the seal member 7, 7A, which may affect the sealing performance. In particular, when the sealing member is in close contact with only the first peak T1 from the tip of the flexible pipe T (as in FIG. 5), the above-mentioned deformation is considered to have a large effect on the sealing performance. In view of this, in the third embodiment, one or more peaks are interposed between the peak to which the sealing member is in close contact and the claws of the retainer, thereby suppressing the adverse effect of the pulling force on the sealing performance.

[0047] A pipe joint according to a third embodiment of the present invention will be described with reference to Figures 9 to 11. The same components as those in the first embodiment described with reference to Figures 1 to 5 are given the same reference numerals and detailed description will be omitted. Figure 9 shows the state before the flexible pipe is inserted, Figure 10 shows the state in the middle of inserting the flexible pipe, and Figure 11 shows the state after the flexible pipe is connected.

[0048] As shown in FIG. 9, the pipe joint 1B is different from the pipe joint of the first embodiment mainly in the configuration of the seal member 7B. Specifically, the seal member 7B of the third embodiment seals one crest of the flexible pipe T like the seal member 7 of the first embodiment, but the entire axial length of the seal member 7B is longer than the entire axial length of the seal member 7. This ensures a space between the claw portion 81 of the retainer 8 and the seal body 71B. As shown in FIG. 10 described later, during the insertion of the flexible pipe T, the first crest T1 from the tip end T3 of the flexible pipe T fits into this space when it rides over the claw portion 81 of the retainer 8. The space is provided with a size such that the first crest T1 does not come into contact with the seal body 71B in this state. Since the state of FIG. 10 is not sealed, the worker can easily determine the connection state of the flexible pipe T by an airtightness test. Therefore, by providing the above-mentioned space between the claw portion 81 of the retainer 8 and the seal body 71B, it is possible to prevent poor connection during construction.

[0049] 9, the seal body 71B has a length sufficient to seal one crest of the flexible pipe T, and the axial length L of the seal body 71B is, for example, 4 mm to 8 mm. The seal body 71B has an inner circumferential portion 711 that comes into close contact with the flexible pipe T, which protrudes toward the rear side of the joint body 2, and the protruding portion is disposed so as to cover part of the inner circumferential surface of the holding member 5. In addition, a convex portion 712 that protrudes in the diameter reducing direction is formed on the rear side of the joint body of the inner circumferential portion 711.

[0050] In Fig. 9, the pressing member 72B has a substantially square cross section and is a ring member having a thicker thickness in the axial direction of the pipe joint than the pressing member 72 of the first embodiment. A recess 721 recessed radially outward is formed on the inner peripheral surface of the pressing member 72B on the inlet side of the joint body 2. As described above, when the flexible pipe T is inserted, the claw portion 81 of the retainer 8 operates to climb over the crest portion T1 of the flexible pipe T, but since the recess 721 is formed, the claw portion 81 of the retainer 8 does not interfere with the pressing member 72B even if the claw portion 81 of the retainer 8 expands in diameter. Therefore, it is possible to prevent an increase in the insertion load of the flexible pipe T due to the claw portion 81 interfering with the seal member 7B.

[0051] Next, FIG. 10 shows the state in the middle of inserting the flexible pipe. In the state of FIG. 10, the inner peripheral portion 711 of the seal body 71B is not in contact with the outer peripheral surface of the flexible pipe T, and is not in a sealed state. Meanwhile, the claw portion 81 of the retainer 8 is accommodated in the valley portion T2 between the first crest portion T1 and the second crest portion from the tip portion T3. In this state, even if the flexible pipe T is pulled, the claw portion 81 abuts against the first crest portion T1, and therefore it will not come out. Meanwhile, when an airtightness test is performed in this state, the flexible pipe T is not in contact with the seal body 71B and is not sealed, and therefore fluid leakage occurs. Therefore, the worker can determine that this state is in the middle of connection. As a result, it becomes easier to prevent poor connection during construction.

[0052] When the flexible pipe T is further inserted from the state of FIG. 10, the inner periphery 711 of the seal body 71B comes into close contact with the peak T1 of the flexible pipe T (see FIG. 11). This connects the flexible pipe T. In the connected state of FIG. 11, the seal body 71B is compressed by being sandwiched between the support part 51 and the pressing member 72B, and the seal surface pressure with the flexible pipe T increases. As a result, the seal body 71B comes into close contact with the first peak T1 from the tip T3 of the flexible pipe T. Also, in FIG. 11, the claw portion 81 of the retainer 8 is accommodated in the valley between the second and third peaks from the tip T3, and one peak is interposed between the peak T1 with which the seal member 7B is in close contact and the claw portion 81 of the retainer 8.

[0053] In this manner, in the third embodiment, one or more ridges are interposed between the ridge T1 to which the seal member 7B is in close contact and the claw 81 of the retainer 8. As a result, for example in FIG. 11, contact between the first ridge T1 from the tip T3 and the claw 81 of the retainer 8 is avoided, and even when a pull-out force is applied to the flexible pipe T, no stress is generated in the first ridge T1 due to contact with the retainer 8. Therefore, the pull-out force does not affect the deformation of the first ridge T1, and therefore the adverse effect of the pull-out force on the sealing performance can be suppressed.

[0054] The configuration of the seal member may be any of the first, second, and third embodiments described above, but the first embodiment is preferred from the viewpoint of further resource saving because the seal member and the pipe joint can be further miniaturized. Specifically, the seal member of the first embodiment is in close contact only with the first crest from the tip of the flexible pipe, so the seal member can be made smaller than the conventional seal member, and the claw portion of the retainer fits into the valley portion adjacent to the first crest from the tip, so the axial length of the pipe joint can be further shortened and the pipe joint can be made smaller. On the other hand, the second embodiment is preferred from the viewpoint of further sealing performance because the contact area between the seal member and the flexible pipe is increased while considering resource saving. In addition, the third embodiment is preferred when the pull-out force is a concern because the effect of the pull-out force on the seal performance can be reduced while considering resource saving. The configuration of the seal member of the third embodiment can also be used as a means for determining the state of the flexible pipe during insertion based on the leak state of the airtightness test.

[0055] In the present invention, the sealing member only needs to be configured to adhere to at least the slope of the tip side of at least the first peak from the tip of the flexible pipe, and may be long enough to seal three or more peaks of the flexible pipe.

[0056] The pipe joint of the present invention is not limited to the above-mentioned embodiments. For example, in the first and second embodiments, a ring-shaped pressing member is used as the pressing member, but as shown in Fig. 15, a pressing member having an L-shaped cross section may be used. In this case, a fireproof packing may be fixed to the pressing member.

[0057] Also, the retainer may be the one shown in Fig. 15. Retainer 18 in Fig. 15 is a ring-shaped member having claw portions 18a and base portion 18b on which tapered surface 18c that abuts against press nut 13 is formed. In the embodiment in Fig. 15, claw portions 18a have an inner diameter larger than the outer diameter of the ridges of the flexible pipe in the unloaded state, and are set to a dimension such that they do not get caught on the ridges when the flexible pipe is inserted. EXAMPLES

[0058] To confirm the sealing performance of the pipe joint of the present invention, a tensile test and a root bending test were carried out. The shape of the seal member shown in FIG. 3 was adopted, and the axial length of the seal body was set to a length that would seal one crest at the tip of the flexible pipe. NBR was used as the rubber material for the seal body. Seal members were obtained using seal bodies with different rubber hardness. The obtained seal members were attached to the joint body to obtain test pipe joints.

[0059] (1) Tensile test As shown in Figure 12, a tensile test was conducted by connecting the test pipe fitting 1 to one end of a SUS304 flexible pipe T (pipe length 150 mm, caliber 20A) and a pipe fitting that would not leak or come off to the other end. A tensile load F of 2.7 kN was applied for 5 minutes with an air pressure of 20 kPa applied inside the pipe, and then the air pressure was reduced to 110 kPa. The presence or absence of leakage during the test was evaluated. The results are shown in Table 1.

[0060] [Table 1]

[0061] As shown in Table 1, Example 1 and Example 2 had excellent airtightness even when subjected to tension. In particular, no leakage was observed in Example 1. On the other hand, in Comparative Examples 1 and 2, leakage occurred in more than half of the cases.

[0062] (2) Root bending test As shown in Figure 13, a base bending test was conducted by connecting a test pipe fitting 1 to a flexible pipe T made of SUS304. With an air pressure of 20 kPa applied inside the pipe, the pipe was bent 90 degrees to the left and right. Specifically, the pipe was bent 90 degrees to the left from the center position and returned to the center, then bent 90 degrees to the right and returned to the center. After returning to the center, the air pressure was set to 110 kPa. The presence or absence of leakage during the test was evaluated. Note that in the test, the number of 90-degree bends to each side was counted as one, and the number of bends that ultimately led to leakage was measured. The results are shown in Table 2.

[0063] [Table 2]

[0064] As shown in Table 2, Example 1 had twice the number of bending times before leakage compared to Comparative Example 1, and was excellent in airtightness even when the flexible pipe was bent. This test result is thought to be due to the fact that the seal body of Example 1 is softer and has better ability to follow the movement of the flexible pipe.

[0065] Here, FIG. 14 shows cross-sectional photographs of the connected state of the pipe joints of Example 1 and Comparative Example 1. FIG. 14(a) shows the periphery of the seal body of Example 1, and FIG. 14(b) shows the periphery of the seal body of Comparative Example 1. In FIG. 14, the outer edge of each seal body is shown with a white line for the purpose of increasing the visibility of the seal body, but in reality, this white line does not exist. As shown in FIG. 14, it can be seen that Example 1 fits the flexible pipe better. Specifically, the seal body of Example 1 is deformed to conform to the shape of the first crest from the tip of the flexible pipe. In particular, the part of the inner circumference of the seal body on the inlet side of the joint body extends into the space between the pressing member and the first crest and is in close contact with the slope on the opposite tip side of the crest. In addition, the contact area between the seal body and the flexible pipe calculated based on the cross-sectional photograph of FIG. 14 was 211.6 mm 2 and Comparative Example 1 is 141.7 mm 2 It was.

[0066] As described above, the pipe joint of the present invention is structured to contact and seal on the slope of the tip side of the first crest from the tip of the flexible pipe, and the conformability is improved by giving the sealing member a specified rubber hardness, and furthermore, the contact area is secured by providing a protrusion, etc., thereby improving the sealing performance. This results in a flexible pipe joint that can conserve resources while maintaining good sealing performance. [Explanation of symbols]

[0067] 1: Pipe fittings (flexible pipe fittings) 2: Fitting body 21: Inner hole 22: Circumferential groove 23: Circumferential groove 24: First stage 25: Second stage 26: Engagement groove 27: Male thread 3: Press nut 31: Outer circumferential groove 4: Elastic material 5: Holding member 51: Support part 52: Bent part 6: Moving parts 61: Flange part 7, 7A, 7B: Sealing material 71, 71A, 71B: Seal body 711: Inner circumference 712: Convex 713: Inclined surface 714: Insertion taper section 72, 72B: Pressing member 721: Recess 8: Retainer 81: Claw part 811: Notched groove 812: Nail piece 82: Base 83: Holding piece 9a: Fireproof packing 9b: Stop ring 9c: O-ring 9d: Lip packing 9e:Selectively permeable material T: Flexible pipe T1: Yamabe T2: Valley T3:Tip

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 inside the joint body are disposed a retainer having a claw portion that fits into a valley portion of the flexible pipe, an elastic member held in a compressed state, a holding member having one end that engages with the inside of the joint body and holds the elastic member in a compressed state, and a ring-shaped seal member that slides toward one end of the joint body and is compressed by the insertion of the flexible pipe and the engagement of the holding member being released and the compressed state of the elastic member being released, thereby coming into close contact with the flexible pipe, A joint for flexible pipes, characterized in that the Shore A hardness of the sealing member is 20 to 30, and the sealing member, when connected to the flexible pipe, is in close contact with at least the slope on the tip side of the first peak portion from the tip of the flexible pipe.

2. 2. A flexible pipe joint as described in claim 1, characterized in that the sealing member has a convex portion protruding in the diameter reduction direction on the rear side of the joint body of the inner periphery that is in close contact with the flexible pipe before the sealing member is compressed.

3. The seal member has a ring-shaped seal body made of a rubber material and a circular flat plate-shaped pressing member fixed to an end surface of the seal body on the inlet side of the joint body, 3. A flexible pipe joint according to claim 1, wherein an inner periphery of the seal body is exposed on the inlet side of the joint body.

4. 4. The flexible pipe joint according to claim 1, wherein the seal member is in close contact with only the first ridge.

5. A flexible pipe joint as described in any one of claims 1 to 4, characterized in that before the flexible pipe is inserted, the retainer is positioned in a state in which the inner diameter of the claw portion is smaller than the outer diameter of the ridge portion of the flexible pipe, and when the flexible pipe is inserted, the claw portion climbs over the ridge portion of the flexible pipe.

6. A flexible pipe joint as described in any one of claims 1 to 5, characterized in that when connected to the flexible pipe, one or more ridges are interposed between the ridges to which the sealing member is in close contact and the claw portions of the retainer.

7. A flexible pipe joint for connecting a bellows-shaped flexible pipe having a plurality of peaks and valleys alternately arranged along an axial direction, comprising: The flexible pipe joint includes a joint body into which the flexible pipe is inserted from one end, and inside the joint body are disposed a retainer having a claw portion that fits into a valley portion of the flexible pipe, an elastic member held in a compressed state, a holding member having one end that engages with the inside of the joint body and holds the elastic member in a compressed state, and a ring-shaped seal member that slides toward one end of the joint body and is compressed by the insertion of the flexible pipe and the engagement of the holding member being released and the compressed state of the elastic member being released, thereby coming into close contact with the flexible pipe, The seal member has a Shore A hardness of 20 to 45, and the seal member is in close contact with at least a tip side slope of a first peak portion from a tip of the flexible pipe when the seal member is connected to the flexible pipe; The seal member has a ring-shaped seal body made of a rubber material and a circular flat plate-shaped pressing member fixed to an end surface of the seal body on the inlet side of the joint body, A joint for flexible pipes, characterized in that an inner peripheral portion of the seal body is exposed on the inlet side of the joint body.

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