Flexible Pipe Fittings

Abstract

To provide a joint for a flexible pipe which is capable of miniaturization while maintaining preferable sealing property.SOLUTION: A pipe joint 1 as the joint for a flexible pipe which connects bellows-like flexible pipes in which a plurality of peak parts and valley parts are alternately arranged along an axial direction includes a joint main body 2 to which the flexible pipe is inserted from one end part. A retainer 4 having a claw part 41, an elastic member 5 freely expandable in the axial direction and a ring-shaped seal member 6 made of rubber material are arranged toward the inner side of the joint main body on an internal part of the joint main body 2, the elastic member 5 energizes the retainer 4 and the seal member 6 in the axial direction in the connection state with the flexible pipe, the claw part 41 of the retainer 4 falls in the valley part of the flexible pipe and, at the same time, the seal member 6 is brought into close contact with the peak part of 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, a pipe joint 11 has a joint body 12 into which a flexible pipe T (see Figure 16) is inserted from one end, and within the joint body 12, a part of a press nut 13, a retainer 14, an elastic member 15 that is axially expandable and contractible, a holding member 17 that holds the elastic member 15 in a compressed state, a moving member 18, and a ring-shaped seal member 16 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 17 and the joint body 12 is released, and the compressed state of the elastic member 15 is released. Then, as the elastic member 15 expands, the seal member 16 slides and is compressed in the axial direction. This brings the seal member 16 into close contact with the outer circumferential surface of the flexible pipe T. Also, as the elastic member 15 expands, the retainer 14 contracts in diameter, and the claw portions 14a fit into the valleys of the flexible pipe T. This causes the retainer 14 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 joint is connected by inserting a flexible pipe into an inner hole of the pipe joint. As shown in Fig. 16, a conventional pipe joint 11 has a structure in which a flexible pipe T is sealed by a seal member 16 that is slid to the inlet side of a joint body 12 by an elastic member 15. Therefore, in the pipe joint 11 of Fig. 16, it is necessary to provide a space for accommodating members such as the elastic member 15 in a space where the flexible pipe T is not inserted (a space on the inner side of the joint body 12 beyond the seal member 16), and therefore the axial length L2 (see Fig. 15) of the pipe joint tends to be long. Therefore, it is considered that there is room for further improvement in terms of miniaturization of pipe joints.

[0007] The present invention has been made in view of the above circumstances, and has an object to provide a flexible pipe joint that can be made smaller 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 arranged alternately along the axial direction, and includes a joint body into which the flexible pipe is inserted from one end, and inside the joint body, a retainer having claws, an elastic member that is axially expandable and contractible, and a ring-shaped seal member made of a rubber material are arranged toward the inner side of the joint body, and when connected to the flexible pipe, the elastic member biases the retainer and the seal member in the axial direction, so that the claws of the retainer fit into the valleys of the flexible pipe and the seal member is in close contact with the peaks of 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. By being in close contact with the flexible pipe, the seal member can reliably seal the fluid inside.

[0009] In the present invention, it is preferable that an annular abutment member is held on the inner circumference of the sealing member before the flexible pipe is inserted, and that the abutment member is a member against which the tip of the flexible pipe is abutted when the flexible pipe is inserted, and which slides toward the rear of the fitting body by being pressed through the flexible pipe.

[0010] In addition, in the present invention, it is more preferable that the sealing member has a convex portion protruding in the radially reducing direction on the inner peripheral portion, and that before the flexible tube is inserted, the convex portion is fitted into an outer peripheral groove formed on the outer peripheral surface of the abutment member to hold the abutment member.

[0011] In the present invention, it is more preferable that, in a connected state with a flexible pipe, one or more crests are interposed between the claws of the retainer and the crests with which the sealing member is in close contact. It is also more preferable that the sealing member is in close contact with only the first crest from the tip of the flexible pipe.

[0012] In the present invention, it is preferable that a prevention member be provided between the elastic member and the seal member for preventing the biasing force of the elastic member from being applied to the seal member before the flexible pipe is inserted.

[0013] Furthermore, in the present invention, the prevention member may be an annular snap-through plate that is deformable from a first position to a second position by snap-through buckling, and the snap-through plate may take the first position before the flexible pipe is inserted and support the elastic member without transmitting the biasing force of the elastic member to the sealing member, and when connected to the flexible pipe, take the second position and transmit the biasing force of the elastic member to the sealing member.

[0014] Furthermore, in the present invention, the prevention member may be a C-shaped member that engages in an expanded diameter state with an inner circumferential groove formed on the inner surface of the fitting body, and when the flexible tube is inserted, it disengages from the inner circumferential groove and reduces in diameter, thereby transmitting the biasing force of the elastic member to the sealing member. Effect of the Invention

[0015] By being configured in this manner, the flexible pipe joint of the present invention can seal the flexible pipe further inside the joint body than with conventional configurations, which allows the axial length of the joint body to be shortened and the joint body to be made smaller while maintaining good sealing properties. [Brief description of the drawings]

[0016] [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 a sealing member and an abutting member shown in FIG. 1. [Figure 4] 2 is a half-sectional view showing a state in which a flexible pipe is being inserted into the pipe joint of FIG. 1. FIG. [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]13 is an enlarged view of the elastic member and its surroundings in a connected state with a flexible pipe. FIG. [Figure 7] FIG. 4 is a half-sectional view of a second embodiment of a pipe joint according to the present invention. [Figure 8] FIG. 8 is a half-sectional view of the pipe joint of FIG. 7 in a state where a flexible pipe is connected. [Figure 9] FIG. 11 is a half-sectional view of a third embodiment of a pipe joint according to the present invention. [Figure 10] FIG. 13 is a diagram showing a first position of the jumping-through plate. [Figure 11] FIG. 13 is a diagram showing a second position of the jumping-through plate. [Figure 12] 10 is a half-sectional view of the pipe joint of FIG. 9 in a state where a flexible pipe is connected. [Figure 13] FIG. 11 is a half-sectional view of a fourth embodiment of a pipe joint according to the present invention. [Figure 14] FIG. 14 is a half-sectional view of the pipe joint of FIG. 13 in a state where a flexible pipe is connected thereto. [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. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] (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 1, 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 side (left side of the figure) of the pipe fitting 1 in Fig. 1, and another pipe, gas equipment, etc. are connected to the other end side (right side of the figure). In the present invention, the direction along the central axis O of the pipe fitting 1 is called the axial direction, the direction perpendicular to the central axis O in a plan view seen from the axial direction is called the radial direction, and the direction going around the central axis O in the plan view is called the circumferential direction.

[0018] Fig. 1 shows the state before the flexible pipe is inserted. As shown in Fig. 1, the pipe joint 1 includes a cylindrical joint body 2 and a press nut 3, a part of which is inserted into the joint body 2. Inside the joint body 2, a retainer 4, an elastic member 5, and a seal member 6 are arranged toward the rear side of the joint body 2. An annular butting member 7 is held on an inner peripheral portion 61 of the seal member 6. Furthermore, in the pipe joint 1, a fireproof packing 8a, a stop ring 8b, an O-ring 8c for sealing the press nut 3 and the joint body 2, a lip packing 8d for sealing the press nut 3 and the flexible pipe T, and a selectively permeable member 8e are respectively attached.

[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 25 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 23 and a second step portion 24 are formed. A seal member 6 is pressed against the first step portion 23 by the biasing force of an elastic member 5. The butting member 7 abuts against the second step portion 24 when connected to the flexible pipe T. In addition, an inner circumferential groove 22 is 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 8b enters is formed on the outer circumferential surface of the press nut 3. An O-ring 8c and a lip packing 8d are fitted in the other grooves of the press nut 3.

[0021] The retainer 4 is a ring-shaped member made of a metal material (e.g., stainless steel). In FIG. 1, the retainer 4 is provided so as to taper toward the inner side of the joint body 2, and is disposed in a state in which the inner diameter of the claw portion 41 is smaller than the outer diameter of the crest portion T1 (see FIG. 4) of the flexible pipe T. The configuration of the retainer 4 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 4 has a hollow disk-shaped base portion 42, a plurality of claw portions 41 extending from the base portion 42 to one side so as to taper, and a plurality of holding pieces 43 extending from the base portion 42 to the opposite side of the claw portions 41.

[0022] The claws 41 are arranged side by side in the circumferential direction and divided by grooves cut in the axial direction. Furthermore, the tip of each claw 41 is divided into two claw pieces 412 by a notched groove 411. By dividing each claw 41 into two claw pieces 412, it becomes easier to fit into the valley portion T2 (see FIG. 4) of the flexible pipe T. Furthermore, the base 42 is formed parallel to a plane perpendicular to the axial direction of the retainer 4. As shown in FIG. 1, the base 42 is arranged parallel to a plane perpendicular to the axial direction of the pipe joint 1, and the fireproof packing 8a abuts against the base 42.

[0023] In FIG. 1, the elastic member 5 is a coil spring that can expand and contract in the axial direction. The elastic member 5 biases the retainer 4 and the seal member 6 in the axial direction. Specifically, the retainer 4 is biased toward the inlet side of the joint body 2 via the fireproof packing 8a and the metal guide 9a, and the seal member 6 is biased toward the inner side of the joint body 2 via the metal guide 9b. The metal guide 9a is a circular member formed with a crank-shaped cross section, and the metal guide 9b is a circular member having an L-shaped cross section. In FIG. 1, the elastic member 5 is held from the inner periphery by the metal guides 9a and 9b.

[0024] The seal member 6 is a ring-shaped member made of a rubber material. In the state shown in FIG. 1, an abutting member 7 is held on the inner peripheral portion 61 of the seal member 6. The configurations of the seal member 6 and the abutting member 7 will be described with reference to FIG. 3. FIG. 3(a) is a half-side cross-sectional view of the seal member and the abutting member, FIG. 3(b) is an enlarged view of the X portion, and FIG. 3(c) is a plan view of the abutting member. As shown in FIGS. 3(a) and 3(b), a metal guide 9b is fixed to the end face of the seal member 6 on the inlet side (left side in the figure) of the joint body 2. The metal guide 9b is fixed to the seal member 6 by, for example, insert molding using a rubber material.

[0025] As shown in FIG. 3(b), the seal member 6 has a convex portion 62 that protrudes in the direction of reducing the diameter at an inner peripheral portion 61 that comes into close contact with the flexible pipe T. The convex portion 62 is fitted into an outer peripheral groove 71 formed on the outer peripheral surface of the abutting member 7, thereby holding the abutting member 7 in the seal member 6. From the viewpoint of holding property and sealing property, the height H of the convex portion 62 is preferably 0.2 mm or more, and a preferable range is 0.2 mm to 1.0 mm. The configuration in which the respective members in FIGS. 3(a) and (b) are integrated is obtained by molding the abutting member 7 and then press-fitting the abutting member 7 into the inner peripheral portion 61 of the seal member 6 on which the metal guide 9b is provided.

[0026] The butting member 7 is a member against which the tip T3 of the flexible pipe T (see FIG. 4) is butted when the flexible pipe T is inserted in the direction of the arrow in the figure. By providing the butting member 7, for example, it is possible to prevent the seal member 6 from being damaged due to the tip T3 of the flexible pipe T coming into contact with the seal member 6. After the tip T3 of the flexible pipe T is butted against the butting member 7, the butting member 7 is further pressed with a force exceeding a predetermined load, so that the butting member 7 is disengaged from the protrusion 62 and slides to the inner side (right side in the figure) of the joint body 2. As will be described later, such a movement of the butting member 7 leads to the suppression of poor connection during construction. The "predetermined load" here refers to a force of a magnitude that allows the butting member 7 to remain without changing its position relative to the seal member 6 due to friction or engagement with the seal member 6.

[0027] In addition, as shown in FIG. 3(b), it is preferable that a side groove 72 into which the tip portion T3 of the flexible pipe T fits is provided on the side surface of the abutting member 7. By providing the side groove 72, even if the abutting member 7 is pressed by the flexible pipe T, the tip portion T3 can be easily held. In addition, since the abutting member 7 is a resin molded body and is softer than the material of the flexible pipe T, deformation of the flexible pipe T can also be prevented. Note that the side groove 72 may be formed on the side surface on the side where the tip portion T3 of the flexible pipe T abuts, but since it is independent of the assembly direction and has excellent weight balance, it is preferable to form the side groove 72 symmetrically on both sides as shown in FIG. 3(b). In addition, as shown in FIG. 3(c), the outer peripheral groove 71 and the side groove 72 are each formed over the entire circumference of the abutting member 7.

[0028] The hardness of the seal member used in the present invention is not particularly limited, and may be, for example, 20 to 60 Shore A hardness. A seal member having a Shore A hardness of about 50, which is the same as that of conventional seal members, may also be used. In a configuration in which the seal member 6 holds the abutting member 7, it is preferable to make the hardness relatively low in consideration of holding and releasing the abutting member 7, and for example, the Shore A hardness is preferably 20 to 40 Shore A hardness. The Shore A hardness is a type A durometer hardness, and refers to a value obtained by the method specified in the Japanese Industrial Standard JIS K 6253-3. In addition, as a rubber material used for the seal member, nitrile butadiene rubber (NBR), which has excellent gas resistance, is preferable because of the need to maintain sealing performance for a long period of time.

[0029] Returning to FIG. 1, other members will be described. The fireproof packing 8a 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 8a is manufactured, for example, by filling a rubber composition obtained 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, etc., into a mold, molding, and then press vulcanizing. The fireproof packing 8a 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 8a has a rectangular cross section.

[0030] The stop ring 8b 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 8b is fitted into the inner circumferential groove 22 of the joint body 2, and the remaining 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. The O-ring 8c is fitted into an outer circumferential groove formed on the inlet side of the joint body 2 from the outer circumferential groove 31 of the press nut 3. The O-ring 8c 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 8d 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 8d seals the outer circumferential surface of the flexible pipe T and the inner circumferential surface of the press nut 3 in a watertight manner. The selectively permeable member 8e is attached to a through hole (e.g., a circular hole) that communicates with the outside air and is provided at a position facing one end side of the joint body 2 of the press nut 3. The selectively permeable member 8e 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 the leaked gas can be detected by an external gas sensor, etc.

[0031] Next, the state of the flexible pipe during insertion will be described with reference to Figure 4. The flexible pipe T is a bellows-shaped metal pipe (e.g., a stainless steel pipe) with multiple peaks T1 and valleys T2 arranged alternately 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 with several peaks (seven peaks in Figure 4) of the outer coating resin removed from the tip T3.

[0032] First, the flexible pipe T is inserted from one end side of the pipe joint 1 and passed through the press nut 3 and the inner periphery of the retainer 4. As described above, the inner diameter of the claw portion 41 of the retainer 4 is arranged in a state where it is smaller than the outer diameter of the crest portion T1 of the flexible pipe T, so that the claw portion 41 operates to climb over the crest portion T1 of the flexible pipe T. When climbing over the crest portion T1, as shown in FIG. 4, the base portion 42 of the retainer 4 presses the fireproof packing 8a, compressing the elastic member 5. After climbing over the crest portion T1, the base portion 42 is pressed by the biasing force of the elastic member 5, and the retainer 4 returns to its normal position. At this time, the claw portion 41 of the retainer 4 fits into the valley portion T2. ​​The flexible pipe T is inserted further in as the retainer 4 climbs over the crest portion T1 of the flexible pipe T crest by crest.

[0033] As shown in FIG. 4, the tip portion T3 of the flexible pipe T abuts against the abutting member 7, and the insertion of the flexible pipe T temporarily stops in that state. In this state, the inner peripheral portion 61 of the seal member 6 is not in contact with the outer peripheral surface of the flexible pipe T, and is not in a sealed state. When the abutting member 7 is further pressed from this state in FIG. 4 and a force exceeding a predetermined load is applied, the abutting member 7 slides toward the back of the joint body 2, and the inner peripheral portion 61 of the seal member 6 comes into close contact with the crest portion T1 of the flexible pipe T (see FIG. 5). This completes the connection of the flexible pipe T. Also, in FIG. 5, the abutting member 7 abuts against the second step portion 24 of the joint body 2, and the insertion of the flexible pipe T does not proceed any further.

[0034] The flexible pipe connection work is performed manually by the installer, but it is possible that the judgment of the completion of the flexible pipe connection may vary from person to person. If the connection work of the flexible pipe T is completed in the state of FIG. 4, a fluid leak will occur. Therefore, in this embodiment, abutment member 7 is provided, and a configuration is created in which the installer feels the abutment member 7 being abutted and the load to slide the abutment member 7 is increased, making it easier for the installer to grasp the completion of the connection of the flexible pipe T. This makes it possible to preferably prevent connection failures during construction. Even if the connection work is completed in the state of FIG. 4, connection failures can be reliably found during testing performed before completion of construction.

[0035] Here, the connection state with the flexible pipe will be further described with reference to FIG. 6. FIG. 6 is an enlarged view of the elastic member 5 and its surroundings in FIG. 5. As shown in FIG. 6, in this state, the elastic member 5 biases the retainer 4 and the seal member 6 in the axial direction. The seal member 6 is compressed by being sandwiched between the metal guide 9b and the first step 23, and is in close contact with the peak T1 of the flexible pipe T. In FIG. 6, the seal member 6 is in close contact with the first peak T1 from the tip T3 of the flexible pipe T. Specifically, the inner peripheral portion 61 of the seal member 6 is in close contact with the slopes on both sides of the first peak T1 so as to cover the first peak T1. In particular, the seal member 6 has a protrusion 62 on the inner peripheral portion 61, and a part of the load from the elastic member 5 acts on the protrusion 62, thereby further improving the close contact with the slope on the opposite tip side of the first peak T1. Furthermore, in this case, by making the seal member 6 have a Shore A hardness of 20 to 40, it can be easily deformed to conform to the shape of the peak portion T1, and the adhesiveness can be further improved.

[0036] 6, the base 42 of the retainer 4 is pressed by the biasing force of the elastic member 5, so that the claw portions 41 are accommodated in the valley portions T2 of the flexible pipe T. Since the base 42 of the retainer 4 is pressed, even if a pulling force is applied to the flexible pipe T, the claw portions 41 are caught in the valley portions T2, thereby preventing the flexible pipe T from coming off.

[0037] In addition, as shown in FIG. 6, it is preferable that the pipe joint 1 has one or more crests (n=3 in FIG. 6) between the claws 41 of the retainer 4 and the crest T1 with which the seal member 6 is in close contact when connected to the flexible pipe T. When a pull-out force is applied to the flexible pipe T, the claws 41 of the retainer 4 may deform the contact portion of the flexible pipe T in some cases. For example, in a configuration in which the claws 41 of the retainer 4 are accommodated in the valleys T2 adjacent to the crest T1 with which the seal member 6 is in close contact, the above-mentioned deformation of the flexible pipe T may affect the sealing properties. In particular, when the seal member 6 is in close contact only with the first crest T1 from the tip of the flexible pipe T, the above-mentioned deformation may have a large effect. Therefore, by having one or more crests between the claws 41 of the retainer 4 and the crest T1 with which the seal member 6 is in close contact, the effect of the pull-out force can be suppressed. Furthermore, in the pipe joint 1, the elastic member 5 is disposed between the retainer 4 and the seal member 6, so that it is easy to ensure a space for interposing one or more ridges between the two.

[0038] As described above, the pipe joint shown in Figs. 1 to 6 can stably hold the flexible pipe and achieve reliable sealing by biasing the retainer and the seal member with the elastic member. In addition, this pipe joint can seal the flexible pipe further inside the joint body because the positional relationship between the elastic member and the seal member inside the joint body is reversed compared to a conventional pipe joint (see Fig. 15). Usually, the dimensions of the male thread portion to which other pipes are connected are determined to some extent by standards, etc. Therefore, by arranging the seal member closer to the male thread portion, that is, further inside the joint body, the space inside the joint body can be effectively used. As a result, the space required for connecting the flexible pipe can be minimized, so the axial length of the pipe joint can be shortened and the pipe joint can be made smaller. This also leads to a reduction in the cost of the pipe joint.

[0039] Thus, in the pipe joint according to the present invention (see Fig. 1), the axial length when the press nut and the joint body are engaged can be made shorter than in a conventional pipe joint (see Fig. 15). For example, while the axial length L2 of a conventional pipe joint is about 70 mm, the axial length L1 of the pipe joint according to the present invention can be, for example, 65 mm or less.

[0040] Second embodiment A pipe joint according to a second embodiment of the present invention will be described with reference to Figures 7 and 8. The same components as those in the first embodiment described with reference to Figures 1 to 6 are given the same reference numerals, and detailed description will be omitted. The same applies to the third and fourth embodiments described below. Figure 7 shows the state before a flexible pipe is inserted, and Figure 8 shows the state after connection with the flexible pipe.

[0041] As shown in Fig. 7, the pipe joint 1A differs from the pipe joint 1 of Fig. 1 mainly in the configuration of the retainer and the metal guide. The retainer 4A is a ring-shaped member having a claw portion 41 and a base portion 42 on which a tapered surface is formed. The retainer 4A is disposed so that its tapered surface abuts against the tip tapered surface of the press nut 3, and the claw portion 41 is provided so as to protrude toward the inner hole 21. The inner diameter of this claw portion 41 is also smaller than the outer diameter of the crest portion T1 (see Fig. 8) of the flexible pipe T. When the flexible pipe T is inserted, the claw portion 41 operates to climb over the crest portion T1 of the flexible pipe T, similar to the above-mentioned retainer 4 (see Fig. 1).

[0042] 7, the metal guide 9aA is a circular member having an L-shaped cross section, and is provided to hold the fireproof packing 8a. Also in FIG.

[0043] In addition, in the pipe joint 1A, a disassembly ring 8f is attached to the outer circumferential groove on the outer circumferential surface of the press nut 3. The disassembly ring 8f is a member that is removed when disassembling the joint body 2 and the press nut 3. By removing this disassembly ring 8f, the press nut 3 can be pushed into the joint body 2 by the thickness of the disassembly ring 8f. As the stop ring 8b is pushed in, it moves to the avoidance groove 221 adjacent to the inner circumferential groove 22 and expands in diameter there, releasing the connection between the joint body 2 and the press nut 3. This makes it possible to disassemble the joint body 2 and the press nut 3.

[0044] Figure 8 shows the pipe joint connected to a flexible pipe. In the pipe joint 1A as well, the elastic member 5 interposed between the retainer 4A and the seal member 6 axially biases them, so that the claws 41 of the retainer 4A fit into the valleys T2 of the flexible pipe T and the seal member 6 comes into close contact with the peaks T1 of the flexible pipe T. This makes it possible to prevent the flexible pipe T from coming loose while also providing a good seal.

[0045] Third embodiment From the viewpoint of sealing performance, it is important that the seal member is compressed when connected to a flexible pipe. Meanwhile, in the pipe joints of the first and second embodiments described above, the urging force of the elastic member acts on the seal member not only when connected to a flexible pipe, but also before the flexible pipe is inserted. If the urging force is always applied before the flexible pipe is inserted, compressive stress is generated in the seal member, and for example, the inner diameter of the seal member may become smaller. In that case, there is a concern that the insertion force of the flexible pipe may become excessive. In view of this, in the third embodiment, a new member is provided to prevent the urging force of the elastic member from being applied to the seal member before the flexible pipe is inserted.

[0046] A half-side cross-sectional view of a pipe joint according to a third embodiment of the present invention is shown in Fig. 9. As shown in Fig. 9, pipe joint 1B is provided with a prevention member 10 between elastic member 5 and seal member 6, which prevents the biasing force of elastic member 5 from being applied to seal member 6 before a flexible pipe is inserted. Note that pipe joint 1B differs from pipe joint 1 in Fig. 1 mainly in that a prevention member is provided and that the metal guide is in the shape of a circular flat plate.

[0047] In FIG. 9, the preventive member 10 is a snap-through plate engaged in an expanded diameter state with a step or inner circumferential groove formed on the inner circumferential surface of the joint body 2. The snap-through plate is a metal annular member that can be deformed from a first position to a second position by snap-through buckling. Here, snap-through buckling refers to buckling that dynamically shifts from a certain equilibrium point to another stable equilibrium point that is not continuous with the first position. The preventive member 10 shown in FIG. 9 is in the first position, and this preventive member 10 will be described with reference to FIG. 10. FIG. 10(a) shows a plan view of the snap-through plate in the first position, FIG. 10(b) shows a cross-sectional view along line AA, and FIG. 10(c) shows an enlarged view of part Y.

[0048] As shown in FIG. 10, the prevention member 10 has a curved portion 101 that is curved so as to protrude toward one axial side. In this first position, the curved portion 101 bulges toward the inlet side (left side in the figure) of the joint body 2. In addition, a plurality of claw pieces 102 spaced apart in the circumferential direction are provided on the outer peripheral edge of the curved portion 101, and these claw pieces 102 are engaged with steps of the joint body 2 by expanding radially outward. In the state of FIG. 10, the prevention member 10 supports the biasing force of the elastic member 5, so that the biasing force can be prevented from being transmitted to the seal member 6. In addition, the inner diameter of the curved portion 101 of the prevention member 10 in the first position is set to be slightly smaller than the outer diameter of the crest T1 (see FIG. 12) of the flexible pipe T. Then, when the flexible pipe T is inserted, the end of the inner diameter side of the curved portion 101 is pressed by the crest T1 of the flexible pipe T, and when a force exceeding a predetermined load is applied, the prevention member 10 changes to the second position (see FIG. 11). 11 , the curved portion 101 bulges out toward the rear side (the right side in the figure) of the joint body 2. In this second position, the claw pieces 102 of the prevention member 10 enter radially inward. Therefore, the prevention member 10 is disengaged from a step or the like of the joint body 2 and contracts in diameter, making it possible to transmit the biasing force of the elastic member 5 to the seal member 6.

[0049] 12 shows a state in which the prevention member 10 is connected to a flexible pipe. In this connected state, the prevention member 10 is in the second position, and transmits the biasing force of the elastic member 5 to the seal member 6. Specifically, the biasing force of the elastic member 5 is transmitted to the seal member 6 via the curved portion 101 and the metal guide 9bA. As a result, when the prevention member 10 is connected to the flexible pipe T, the seal member 6 is compressed, thereby ensuring the sealing performance.

[0050] In this way, by using the jump-through plate as the prevention member, it is possible to reliably prevent the biasing force of the elastic member from being applied to the seal member before the insertion of the flexible pipe while ensuring the sealing performance. Before the insertion of the flexible pipe, the jump-through plate is held in the first position (a state inverted from the stable state). The portion that receives the biasing force of the elastic member is near the center between the outer diameter and the inner diameter of the jump-through plate, and the inverted state is not canceled. Then, when the end of the jump-through plate on the inner diameter side is pressed with a predetermined load (for example, about 100N to 150N) by the insertion of the flexible pipe, the inverted state of the jump-through plate is canceled and the jump-through plate moves to the second position. That is, the jump-through plate does not move to the second position unless the flexible pipe is inserted, so that the transmission of the biasing force can be reliably prevented before the insertion of the flexible pipe. Furthermore, the jump-through plate generates a sound or produces a clear difference in feel when moving from the first position to the second position. Therefore, the operator can reliably sense, by hearing and touch, that the insertion of the tube has been completed.

[0051] (Fourth embodiment) In a pipe joint according to a fourth embodiment of the present invention, another member is used as the above-mentioned prevention member. A half-side cross-sectional view of this fourth embodiment is shown in Fig. 13. As shown in Fig. 13, in a pipe joint 1C, a prevention member 10A is provided between an elastic member 5 and a seal member 6. The pipe joint 1C differs from the pipe joint 1A in Fig. 7 mainly in that a prevention member is provided, the position of the fireproof packing, and the orientation of the metal guide.

[0052] The prevention member 10A shown in Fig. 13 is a C-shaped member having a joint in a portion of the circumferential direction, and has a radially expanded flange portion 103. In the state before the flexible pipe is inserted as shown in Fig. 13, the prevention member 10A is engaged with the inner circumferential groove 27 of the joint body 2 in an expanded diameter state by the flange portion 103, and is disposed with its inner peripheral edge abutting against the metal guide 9b.

[0053] When the flexible pipe T (see FIG. 14) is inserted in the state of FIG. 13, the abutting member 7 is pressed by the tip of the flexible pipe T. This pressing causes the convex portion 62 of the seal member 6 to receive a load, and the seal member 6 is deformed, displacing the metal guide 9b. Then, the flange portion 103 of the prevention member 10A is disengaged from the inner circumferential groove 27, and the prevention member 10A is reduced in diameter. As a result, the biasing force of the elastic member 5 can be transmitted to the seal member 6. FIG. 14 shows a state in which the flexible pipe is connected, and in this connected state, the biasing force of the elastic member 5 is transmitted to the seal member 6 via the prevention member 10A and the metal guide 9b. In the fourth embodiment, the seal member 6 is compressed in the connected state to the flexible pipe T, thereby ensuring sealing performance.

[0054] In the fourth embodiment, the part management of the prevention member is easier than in the third embodiment. That is, the jump-through plate in the third embodiment needs to be assembled in a state inverted from a stable state before being assembled to the joint body. At this time, it is necessary to prevent a load from being applied to the end of the prevention member on the inner diameter side in the inverted state, and careful handling is required. On the other hand, since the C-shaped member in the fourth embodiment is in a stable state itself, it is sufficient to push the gap wide during assembly and bring it into contact with the metal guide, so careful handling of each part is not so required. Note that the prevention member is not limited to a jump-through plate or a C-shaped member as long as it is a member that prevents the biasing force of the elastic member from being applied to the seal member before the flexible pipe is inserted.

[0055] In the fourth embodiment, as shown in Fig. 13, the fireproof packing 8a is accommodated in an inner circumferential groove 26 formed on the inner circumferential surface of the joint body 2. The inner circumferential groove 26 is formed on the inner circumferential side of the joint body 2 with respect to the inner circumferential groove 22 into which a part of the stop ring 8b is fitted. In Fig. 13, the base 42 of the retainer 4A abuts against the metal guide 9aA, and the biasing force of the elastic member 5 is transmitted to the retainer 4A. As shown in Fig. 13, by accommodating the fireproof packing in the inner circumferential groove of the joint body without contacting the retainer, the length of the fireproof packing can be omitted from the joint body.

[0056] The pipe joint of the present invention is not limited to the configuration of each of the above-mentioned embodiments. For example, in each of the embodiments, the seal member is configured to be in close contact with only the first peak from the tip of the flexible pipe, but this is not limited thereto. For example, the seal member may be in close contact with two or more peaks including the first peak from the tip, or the seal member may be in close contact with one or more peaks excluding the first peak from the tip of the flexible pipe. From the viewpoint of further miniaturization of the pipe joint, it is preferable to make the seal member in close contact with at least the first peak from the tip of the flexible pipe.

[0057] Furthermore, the shapes, arrangements, etc. of the components employed in each of the above embodiments can be appropriately combined with the configurations of other embodiments.

[0058] As described above, the pipe joint of the present invention can be made smaller while maintaining good sealing properties, and is therefore excellent in terms of resource conservation. [Explanation of symbols]

[0059] 1, 1A, 1B, 1C: Pipe fittings (flexible pipe fittings) 2: Fitting body 21: Inner hole 22: Inner groove 23: First stage 24: Second stage 25: Male thread 26: Inner groove 27: Inner groove 3: Press nut 31: Outer circumferential groove 4, 4A: Retainer 41: Claw part 411: Notched groove 412: Nail piece 42: Base 43: Holding piece 5: Elastic material 6: Sealing material 61: Inner circumference 62: Convex 7: Stopper part 71: Outer circumferential groove 72: Gutter 8a: Fireproof packing 8b: Stop ring 8c: O-ring 8d: Lip packing 8e: Selectively permeable material 8f: Disassembly ring 9a, 9aA: Metal guide 9b, 9bA: Metal guide 10, 10A: Prevention member 101: Curved section 102: Nail piece 103: Flange part 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 joint body includes a joint into which the flexible pipe is inserted from one end, and a press nut having a portion inserted into the joint body. Inside the joint body, a retainer having a claw portion, an elastic member which is expandable and contractable in the axial direction, and a ring-shaped seal member made of a rubber material are disposed toward the inner side of the joint body, A flexible pipe joint characterized in that, when connected to the flexible pipe, the elastic member biases the retainer and the sealing member in the axial direction, so that the claw portions of the retainer fit into the valley portions of the flexible pipe and the sealing member is in close contact with the peak portions of the flexible pipe.

2. an annular abutting member is held on an inner periphery of the seal member before the flexible pipe is inserted; A flexible pipe joint as described in claim 1, characterized in that the abutment member is a member that is abutted by the tip of the flexible pipe when the flexible pipe is inserted and is pressed through the flexible pipe, thereby sliding toward the rear side of the joint body.

3. The flexible pipe joint as described in claim 2, characterized in that the sealing member has a convex portion protruding in a radially reducing direction on the inner peripheral portion, and before the flexible pipe is inserted, the convex portion is fitted into an outer peripheral groove formed on the outer peripheral surface of the abutment member to hold the abutment member.

4. A flexible pipe joint as described in any one of claims 1 to 3, characterized in that when connected to the flexible pipe, one or more ridge portions are interposed between the claw portion of the retainer and the ridge portion to which the sealing member is in close contact.

5. 5. The flexible pipe joint according to claim 1, wherein the seal member is in close contact with only the first peak from the tip of the flexible pipe.

6. A flexible pipe joint as claimed in any one of claims 1 to 5, characterized in that a prevention member is provided between the elastic member and the sealing member to prevent the biasing force of the elastic member from being applied to the sealing member before the flexible pipe is inserted.

7. 7. The flexible pipe joint according to claim 6, wherein the prevention member is an annular snap-through plate that is deformable from a first position to a second position by snap-through buckling, and the snap-through plate takes the first position before the flexible pipe is inserted and supports the elastic member without transmitting the biasing force of the elastic member to the sealing member, and takes the second position in a connected state with the flexible pipe and transmits the biasing force of the elastic member to the sealing member.

8. The flexible pipe joint as described in claim 6, characterized in that the prevention member is a C-shaped member that engages in an expanded diameter state with an inner circumferential groove formed on the inner surface of the joint body, and when the flexible pipe is inserted, it disengages from the inner circumferential groove and reduces in diameter, thereby transmitting the biasing force of the elastic member to the sealing member.

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