Pipe joint

Abstract

To facilitate suppression of loosening of a nut while enabling easier perception of tightening completion of the nut.SOLUTION: A pipe joint 20 comprises a tubular joint body 40, a nut 44, and an engagement projection 48. The engagement projection 48 is disposed at a position adjacent to a base portion of a male screw 62 of the joint body 40, as viewed from a tip end of the male screw. The engagement projection 48 protrudes along a central axis of the male screw 62. The nut 44 includes at least one engagement recess 104, and a covering part 108. The engagement recess 104 faces toward the base portion when a female screw 102 of the nut 44 engages with the male screw 62 of the joint body 40. The engagement recess 104 faces the engagement projection 48 when the female screw 102 engages with the male screw 62. The covering part 108 faces toward the base portion of the male screw 62 when the female screw 102 engages with the male screw 62. The covering part 108 is disposed to surround the central axis of the female screw 102.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a pipe joint. [Background technology]

[0002] Patent Document 1 discloses a pipe joint. This pipe joint connects steel pipes each having a bulged portion with an arc-shaped cross section formed on the outer periphery of its end. This pipe joint has a joint body, an O-ring mounting groove, an O-ring, an annular groove, a stopper ring, a fitting portion, and a nut. The joint body has an insertion portion into which the steel pipe is inserted. Male threads are formed on the outer periphery of both ends of the joint body. An O-ring mounting groove is provided on the inner periphery of the joint body. An O-ring is disposed in this O-ring mounting groove. The O-ring abuts against the bulged portion of the steel pipe. An annular groove is provided adjacent to the end of the male thread of the joint body. A stopper ring is disposed in the annular groove. The fitting portion faces the joint body across the bulged portion of the steel pipe and fits onto the steel pipe. The nut has a female thread and a notch. The female thread engages with the male thread of the joint body. The notch is provided on the inner peripheral surface of the female thread portion on the opening side of the fitting body. The notch engages with a stopper ring. The pipe fitting disclosed in Patent Document 1 can prevent seizure during tightening and can prevent the nut from loosening after tightening. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-256945 Summary of the Invention [Problem to be solved by the invention]

[0004] The pipe joint disclosed in Patent Document 1 is capable of preventing the nut from loosening, but has the problem that it is not very easy to sense when the nut has been tightened.

[0005] An object of the present invention is to make it easier to prevent a nut from loosening while also making it easier to perceive when the nut has been tightened. [Means for solving the problem]

[0006] The pipe joint of the present invention will be described with reference to the drawings. Note that the reference numerals used in this section are intended to facilitate understanding of the invention, and are not intended to limit the scope of the invention to that shown in the drawings.

[0007] To achieve the above-mentioned object, according to one aspect of the present invention, a pipe fitting 20 includes a cylindrical fitting body 40 and a nut 44. The fitting body 40 has an external thread 62. The external thread 62 is disposed on the outer periphery of at least one end of the fitting body 40. The nut 44 has an internal thread 102 and a pipe communication retaining portion 100. The internal thread 102 engages with the external thread 62 of the fitting body 40. The pipe communication retaining portion 100 is connected to the internal thread 102. The pipe communication retaining portion 100 holds the pipe 200 so that the interior of the pipe 200 is in communication with the interior of the fitting body 40. The pipe fitting 20 further includes an engaging protrusion 48. The engaging protrusion 48 is disposed at a position adjacent to the base of the external thread 62 when viewed from the tip of the external thread 62. The engaging protrusion 48 protrudes along the central axis of the external thread 62. The nut 44 further has at least one engagement recess 104 and a covering portion 108. The engagement recess 104 faces toward the root of the male thread 62 when the female thread 102 meshes with the male thread 62 of the joint body 40. The engagement recess 104 faces the engagement protrusion 48 when the female thread 102 meshes with the male thread 62 of the joint body 40. The covering portion 108 faces toward the root of the male thread 62 when the female thread 102 meshes with the male thread 62 of the joint body 40. The covering portion 108 is arranged to surround the central axis of the female thread 102.

[0008] The engagement recess 104 faces the engagement protrusion 48 when the female thread 102 of the nut 44 engages with the male thread 62 of the joint body 40. As a result, the engagement recess 104 engages with the engagement protrusion 48 when the female thread 102 of the nut 44 engages with the male thread 62 of the joint body 40. As a result, when the nut 44 attempts to loosen, the engagement recess 104 engaged with the engagement protrusion 48 is less likely to come off the engagement protrusion 48. Because the engagement recess 104 is less likely to come off the engagement protrusion 48, loosening of the nut 44 is suppressed. As loosening of the nut 44 is suppressed, the engagement recess 104 engages with the engagement protrusion 48 little by little. Because this engagement occurs little by little, the engagement is possible without applying a large force. On the other hand, the covering portion 108 faces the root of the male thread 62 when the female thread 102 engages with the male thread 62 of the joint body 40. The covering portion 108 is disposed so as to surround the central axis of the female thread 102. As a result, as the engagement of the engagement recess 104 with the engagement protrusion 48 progresses little by little, the covering portion 108 gradually covers either the joint body 40 or the engagement protrusion 48. Either the joint body 40 or the engagement protrusion 48 is covered. This coverage makes it easy to sense whether the engagement of the engagement recess 104 with the engagement protrusion 48 is progressing. As a result, it is easy to prevent the nut 44 from loosening, while also making it easier to sense when the nut 44 has been fully tightened.

[0009] It is also desirable that the above-described pipe fitting 20 further includes an index portion 132. The index portion 132 is located closer to the front than the base of the engaging protrusion 48 when viewed from the tip of the male thread 62. In this case, it is desirable that the distance from the covering portion 108 to the central axis of the female thread 102 of the nut 44 is longer than the distance from the index portion 132 to the central axis of the male thread 62.

[0010] The distance from the covering portion 108 to the central axis of the female thread 102 of the nut 44 is longer than the distance from the index portion 132 to the central axis of the male thread 62. This allows the covering portion 108 to gradually cover the index portion 132 as the engagement of the engaging recess 104 with the engaging protrusion 48 progresses. This coverage makes it easy to perceive whether the engagement of the engaging recess 104 with the engaging protrusion 48 is progressing. As a result, it is easy to prevent the nut 44 from loosening, while also making it easier to perceive when the nut 44 has been fully tightened.

[0011] Alternatively, it is desirable that the covering portion 108 described above be disposed outside the engaging recess 104 when viewed from the position of the central axis of the female thread 102. In this case, it is desirable that the indicator portion 132 be disposed outside the engaging protrusion 48 when viewed from the position of the central axis of the male thread 62.

[0012] When the indicator portion 132 is positioned outside the engaging protrusion 48 when viewed from the position of the center axis of the male thread 62, the indicator portion 132 is less likely to be obstructed by the engaging protrusion 48. When the indicator portion 132 is less likely to be obstructed, it becomes easier to perceive whether the engagement of the engaging recess 104 with the engaging protrusion 48 is progressing. As a result, it becomes easier to perceive that the nut 44 has been tightened, while easily preventing loosening. [Effects of the Invention]

[0013] According to the present invention, it is easy to prevent the nut from loosening, and it is also easier to sense when the nut has been tightened. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is an external view of a pipe joint according to an embodiment of the present invention. [Figure 2] FIG. 1 is a perspective view of a fitting body according to an embodiment of the present invention. [Figure 3] FIG. 1 is a side view of a fitting body according to an embodiment of the present invention. [Figure 4] 1 is an external view of a nut according to an embodiment of the present invention. FIG. [Figure 5] FIG. 2 is a perspective view of a housing portion and an engaging protrusion according to an embodiment of the present invention. [Figure 6] 1 is an external view of a spacer according to an embodiment of the present invention. [Figure 7] 1 is a diagram showing an installation state of a spacer according to an embodiment of the present invention. [Figure 8] 10 is a view showing the inside of the fitting body in a state where one end of the pipe abuts against the annular end wall portion of the entry direction correction tube in an embodiment of the present invention. FIG. [Figure 9] 1 is a diagram showing the inside of a joint body in a state in which a sealing material is expanded radially outward from its inner periphery in an embodiment of the present invention. FIG. [Figure 10] 10 is a diagram showing a state in which an engagement protrusion and an engagement recess are gradually approaching each other in an embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the same components are designated by the same reference numerals. Their names and functions are the same. Therefore, detailed descriptions thereof will not be repeated.

[0016] [Pipe fitting configuration] Fig. 1 is an external view of a pipe fitting 20 according to this embodiment. In Fig. 1, two pipes 200, 200 are connected to the pipe fitting 20 according to this embodiment. In Fig. 1, the objects shown are shown with portions cut away. Below, the configuration of the pipe fitting 20 according to this embodiment will be described based on Fig. 1.

[0017] The pipe fitting 20 according to this embodiment is used to connect two pipes 200, 200 to each other. The pipe fitting 20 is connected to one end of one of the pair of pipes 200, 200 and the other end of the other. The pipe fitting 20 allows fluid flowing through one of the pair of pipes 200, 200 to pass to the other. The pipe 200 according to this embodiment has a pipe flow path forming portion 220, an engagement enlarged diameter portion 222, and a seal facing portion 224. The pipe flow path forming portion 220 forms a flow path. The engagement enlarged diameter portion 222 is formed closer to one end of the pipe 200 than the pipe flow path forming portion 220. The engagement enlarged diameter portion 222 forms a space communicating with the flow path formed by the pipe flow path forming portion 220. The engagement enlarged diameter portion 222 has a larger outer diameter than the pipe flow path forming portion 220. The seal facing portion 224 is formed closer to one end of the pipe 200 than the engagement enlarged diameter portion 222. The seal facing portion 224 forms a space, which will be described below. This space communicates with the flow path formed by the pipe flow path forming portion 220 and the space formed by the engagement enlarged diameter portion 222.

[0018] As shown in FIG. 1, the pipe fitting 20 of this embodiment comprises a cylindrical fitting body 40, a pair of annular seal members 42, 42, a pair of nuts 44, 44, a pair of annular accommodating portions 46, 46, a plurality of engaging protrusions 48, 48, a pair of entry direction correction tubes 50, 50, and a pair of spacers 52, 52.

[0019] The joint body 40 is a member that forms the main body of the pipe joint 20. Both of the two pipes 200, 200 enter the joint body 40. One of the two pipes 200, 200 enters from one end of the joint body 40, and the other of the two pipes 200, 200 enters from the other end of the joint body 40.

[0020] The pair of seals 42, 42 are both disposed within the joint body 40. The pair of seals 42, 42 together seal between the outer peripheral surface of the pipe 200 and the inner peripheral surface of the joint body 40. One of the pair of seals 42, 42 seals between the inner peripheral surface of the joint body 40 and one of the two pipes 200, 200. The other of the pair of seals 42, 42 seals between the inner peripheral surface of the joint body 40 and the other of the two pipes 200, 200.

[0021] The pair of nuts 44, 44 are connected to one end and the other end of the joint body 40. One of the two tubes 200, 200 passes through one of the pair of nuts 44, 44, and the other of the two tubes 200, 200 passes through the other of the pair of nuts 44, 44.

[0022] One end of the joint body 40 passes through one of the pair of receiving portions 46, 46. The other end of the joint body 40 passes through the other of the pair of receiving portions 46, 46.

[0023] Some of the multiple engaging protrusions 48, 48 are intended to engage with one of the pair of nuts 44, 44. In the present embodiment, some of the multiple engaging protrusions 48, 48 protrude from one of the pair of accommodating portions 46, 46. Other several of the multiple engaging protrusions 48, 48 are intended to engage with the other of the pair of nuts 44, 44. In the present embodiment, some other several of the multiple engaging protrusions 48, 48 protrude from the other of the pair of accommodating portions 46, 46.

[0024] The pair of entry direction correction cylinders 50, 50 are both housed within the joint body 40. The entry direction correction cylinder 50 corrects the entry direction of the pipe 200 that is entering the joint body 40.

[0025] One end of the joint body 40 passes through one of the pair of spacers 52, 52. The other end of the joint body 40 passes through the other of the pair of spacers 52, 52.

[0026] [Fitting body configuration] Fig. 2 is a perspective view of the joint body 40 according to this embodiment. Fig. 3 is a side view of the joint body 40 according to this embodiment. In Fig. 3, the illustrated objects are shown with portions thereof cut away. The configuration of the joint body 40 according to this embodiment will be described below with reference to Figs. 2 and 3.

[0027] The joint body 40 according to this embodiment has a joint flow path forming portion 60, a pair of male threads 62, 62, and a pair of displacement prevention portions 64, 64.

[0028] The joint flow path forming portion 60 forms a flow path. Water or other fluid passes through this flow path. The fluid flowing through this flow path and the fluid flowing through the two pipes 200, 200 are the same.

[0029] One of the pair of male threads 62, 62 is disposed on the outer periphery of one end of the joint flow path forming portion 60. The other of the pair of male threads 62, 62 is disposed on the outer periphery of the other end of the joint flow path forming portion 60.

[0030] In the present embodiment, one of the pair of accommodating portions 46, 46 described above is disposed at a position adjacent to the root of one of the pair of male threads 62, 62 when viewed from the tip of that male thread 62. Some of the above-described multiple engaging protrusions 48, 48 protrude along the central axis 180 of the joint flow path forming portion 60. In the present embodiment, the central axes of the pair of male threads 62, 62 all coincide with the central axis 180 of the joint flow path forming portion 60. As a result, some of the above-described multiple engaging protrusions 48, 48 protrude from one of the pair of accommodating portions 46, 46 along the central axis of one of the pair of male threads 62, 62.

[0031] As described above, in this embodiment, the central axes of the pair of male threads 62, 62 both coincide with the central axis 180 of the joint flow path forming portion 60. In this embodiment, the pair of accommodating portions 46, 46 are both arranged in a state where rotation around the central axis 180 of the joint flow path forming portion 60 of the joint body 40 is restricted. As a result, one of the pair of accommodating portions 46, 46 is arranged in a state where rotation around the central axis of one of the pair of male threads 62, 62 is restricted. The other of the pair of accommodating portions 46, 46 is arranged in a state where rotation around the central axis of the other of the pair of male threads 62, 62 is restricted.

[0032] Similarly, in the present embodiment, the other of the pair of accommodating portions 46, 46 described above is disposed at a position adjacent to the root of the other of the pair of male threads 62, 62 when viewed from the tip of that male thread 62. Several other of the plurality of engaging protrusions 48, 48 described above protrude along the central axis 180 of the joint flow path forming portion 60. As a result, several other of the plurality of engaging protrusions 48, 48 described above protrude from the other of the pair of accommodating portions 46, 46 along the central axis of the other of the pair of male threads 62, 62.

[0033] The slippage prevention portion 64 according to this embodiment is an annular portion that protrudes from the outer periphery of the joint flow-channel forming portion 60. One of the pair of slippage prevention portions 64, 64 prevents one of the pair of accommodating portions 46, 46 from slipping in the circumferential direction about the central axis 180 of the joint flow-channel forming portion 60, and therefore about the central axis of the male thread 62. In this regard, the one of the pair of slippage prevention portions 64, 64 allows movement of one of the pair of accommodating portions 46, 46 toward the back when viewed from the tip of one of the pair of male threads 62, 62.

[0034] The other of the pair of slippage prevention portions 64, 64 prevents the other of the pair of accommodating portions 46, 46 from slipping in the circumferential direction around the central axis 180 of the joint flow path forming portion 60, and therefore the central axis of the male thread 62. In this regard, the other of the pair of slippage prevention portions 64, 64 allows the other of the pair of accommodating portions 46, 46 to move inward when viewed from the tip of one of the pair of male threads 62, 62.

[0035] In this embodiment, each pair of slippage prevention portions 64, 64 has a plurality of exposed recesses 90, 90. The exposed recesses 90 are arranged on the outer periphery of the slippage prevention portion 64. The exposed recesses 90 are arranged so as to be exposed. The exposed recesses 90 are recessed. The exposed recesses 90 penetrate toward the central axis 180 of the joint flow path forming portion 60. A rotation prevention protrusion 134 (described below) of the accommodating portion 46 fits into one of the exposed recesses 90. By fitting the rotation prevention protrusion 134 into the exposed recess 90 that penetrates toward the central axis 180 of the joint flow path forming portion 60, slippage of the accommodating portion 46 in the circumferential direction around the central axis of the male thread 62 is prevented. Movement of the accommodating portion 46 toward the back when viewed from the tip of the male thread 62 is possible.

[0036] In this embodiment, the joint flow path forming portion 60 has a communication path forming portion 80, a pair of pipe end accommodating portions 82, 82, and a pair of sealing material accommodating portions 84, 84.

[0037] One of the pair of pipe end accommodating sections 82, 82 is arranged adjacent to one end of the communicating passage forming section 80. The other of the pair of pipe end accommodating sections 82, 82 is arranged adjacent to the other end of the communicating passage forming section 80. In other words, the pair of pipe end accommodating sections 82, 82 are arranged adjacent to each other with the communicating passage forming section 80 in between. One of the pair of pipe end accommodating sections 82, 82 accommodates one end of one of the pipes 200, 200. The other of the pair of pipe end accommodating sections 82, 82 accommodates the other end of the pipes 200, 200.

[0038] One of the pair of sealing material accommodating portions 84, 84 is arranged adjacent to one of the pair of pipe end accommodating portions 82, 82. One of the pair of sealing material accommodating portions 84, 84 accommodates one of the pair of sealing materials 42, 42. One end of one of the pair of pipes 200, 200 passes through one of the pair of sealing material accommodating portions 84, 84.

[0039] The other of the pair of sealing material accommodating portions 84, 84 is disposed adjacent to the other of the pair of pipe end accommodating portions 82, 82. The other of the pair of sealing material accommodating portions 84, 84 accommodates the other of the pair of sealing materials 42, 42. The other ends of the pipes 200, 200 pass through the other of the pair of sealing material accommodating portions 84, 84.

[0040] [Nut configuration] 4 is an external view of the nut 44 according to this embodiment. The configuration of the nut 44 according to this embodiment will be described below with reference to FIG.

[0041] The nut 44 according to this embodiment has a pipe communication holding portion 100, a female thread 102, a number of engagement recesses 104, eight nut outer peripheral recesses 106, and a covering portion .

[0042] The pipe communication holding portion 100 holds the pipe 200 so that the inside of the pipe 200 is in communication with the inside of the joint body 40. In this embodiment, the pipe communication holding portion 100 houses the engagement enlarged diameter portion 222 of the pipe 200.

[0043] The female thread 102 is connected to the pipe communication holding portion 100. The female thread 102 connects the pipe communication holding portion 100 to the joint body 40. In the present embodiment, the female thread 102 of one of the pair of nuts 44, 44 engages with one of the pair of male threads 62, 62 of the joint body 40. The female thread 102 of the other of the pair of nuts 44, 44 engages with the other of the pair of male threads 62, 62 of the joint body 40. As a result, the pipe communication holding portion 100 holds the pipe 200 so that the interior of the pipe 200 is in communication with the interior of the joint body 40.

[0044] The engagement recesses 104 are positioned to face the engagement protrusions 48 when the female threads 102 are engaged with the male threads 62 of the joint body 40. As a result, in the present embodiment, the engagement recesses 104 of one of the pair of nuts 44, 44 face some of the multiple engagement protrusions 48, 48 when the female threads 102 of one of the pair of nuts 44, 44 are engaged with one of the pair of male threads 62, 62. The engagement recesses 104 of the other of the pair of nuts 44, 44 face some other of the multiple engagement protrusions 48, 48 when the female threads 102 of the other of the pair of nuts 44, 44 are engaged with the other of the pair of male threads 62, 62.

[0045] In this embodiment, the nut outer periphery recess 106 is disposed on the outer periphery of the pipe communication holding part 100. The nut outer periphery recess 106 forms a groove. In this embodiment, one end of the groove formed by the nut outer periphery recess 106 is closed by the covering part 108.

[0046] In the present embodiment, the covering portion 108 is disposed at a location that faces the root of the male thread 62 when the female thread 102 meshes with the male thread 62 of the fitting body 40. The covering portion 108 is disposed so as to surround the central axis of the female thread 102 and, therefore, the central axis 182 of the pipe communication holding portion 100. Furthermore, in the present embodiment, the covering portion 108 is disposed outside the engagement recess 104 when viewed from the position of the central axis of the female thread 102 and, therefore, the central axis 182 of the pipe communication holding portion 100.

[0047] [Configuration of the storage unit] 5 is a perspective view of the accommodating portion 46 and the engaging protrusion 48 according to this embodiment. The configuration of the accommodating portion 46 according to this embodiment will be described below with reference to FIG.

[0048] In this embodiment, the housing portion 46 has a housing main body portion 130, an indicator portion 132, and an anti-rotation protrusion 134.

[0049] The accommodating body portion 130 forms an accommodating space therein. The accommodating space extends along the central axis of the male thread 62 when the fitting body 40 passes through the accommodating portion 46. The accommodating space opens toward the tip of the male thread 62. A portion of the engaging protrusion 48 is accommodated within the accommodating space. Another portion of the engaging protrusion 48 protrudes outside the accommodating body portion 130.

[0050] The indicator portion 132 is connected to the accommodating main body portion 130. The indicator portion 132 is intended to be disposed closer to the male thread 62 than the accommodating main body portion 130. In this embodiment, the distance from the covering portion 108 to the central axis of the female thread 102 of the nut 44, and therefore to the central axis 182 of the pipe communication holding portion 100, is longer than the distance from the indicator portion 132 to the central axis of the male thread 62. Furthermore, in this embodiment, the indicator portion 132 is disposed outside the engaging protrusion 48 when viewed from the position of the central axis of the male thread 62. In this embodiment, the indicator portion 132 is colored a different color from the accommodating main body portion 130. This makes the indicator portion 132 easily recognizable.

[0051] The anti-rotation protrusion 134 is disposed on the reverse side of the surface of the housing body 130 on which the indicator portion 132 is disposed. The anti-rotation protrusion 134 engages with one of the exposure recesses 90.

[0052] [Spacer configuration] Fig. 6 is an external view of the spacer 52 according to this embodiment. Fig. 7 is a view showing an attachment state of the spacer 52 according to this embodiment. The configuration of the spacer 52 according to this embodiment will be described with reference to Figs. 6 and 7.

[0053] The spacer 52 has an occupying body 120 and a pair of body engaging portions 122,122.

[0054] The occupying body 120 is disposed between the slippage prevention portion 64 and the accommodation portion 46 so as to be in close contact with the accommodation portion 46. The occupying body 120 has a ring-like shape with a portion separated so as to be openable and closable.

[0055] The main body engaging portion 122 protrudes from the occupying main body 120 in a direction along the central axis 184 of the occupying main body 120. One of the pair of main body engaging portions 122, 122 protrudes from one end of the occupying main body 120 at a portion that is separated so as to be able to be opened and closed. The other of the pair of main body engaging portions 122, 122 protrudes from the other end of the occupying main body 120 at a portion that is separated so as to be able to be opened and closed.

[0056] In this embodiment, the occupying body 120 of the spacer 52 is disposed between the slip prevention portion 64 and the accommodating portions 46, 46. By disposing the occupying body 120 there, movement of the accommodating portion 46 in a direction toward the slip prevention portion 64 is prevented. As a result, once the engaging protrusion 48 engages with the engaging recess 104, the engagement is difficult to release. Because the engagement is difficult to release, the connection between the fitting body 40 and the nut 44 is also difficult to release. On the other hand, when the occupying body 120 is removed, the accommodating portion 46 can easily move in a direction toward the slip prevention portion 64. When the accommodating portion 46 can easily move, the engagement between the engaging protrusion 48 and the engaging recess 104 can easily be released. As a result, the connection between the fitting body 40 and the nut 44 can also be easily released.

[0057] As described above, in this embodiment, the anti-rotation protrusion 134 of the accommodating portion 46 fits into the exposed recess 90 of the slippage prevention portion 64, thereby positioning the accommodating portion 46 in a state where rotation about the central axis 180 of the joint flow-path forming portion 60 is restricted. As shown in Figure 7, in this embodiment, the pair of main body engaging portions 122, 122 of the spacer 52 fit into the gap formed between the exposed recess 90 and the anti-rotation protrusion 134. This prevents the spacer 52 from falling off due to vibration or other accidental factors.

[0058] [How to connect pipe fittings] The method for connecting the pair of pipes 200, 200 and the pipe joint 20 according to this embodiment is as follows: First, an operator passes the nut 44 through a commercially available steel pipe.

[0059] Once the steel pipe has passed through the nut 44, the worker uses a well-known method to expand the portion of the steel pipe that has already passed through the nut 44. This forms the expanded diameter engaging portion 222 and the seal facing portion 224 according to this embodiment. As a result, one of the pair of pipes 200, 200 according to this embodiment is completed.

[0060] Next, the worker inserts the tip portion of the pipe 200 that has passed through the nut 44 into one end of the joint flow path forming portion 60. The end of the pipe 200 that has entered the joint flow path forming portion 60 passes through one of the pair of sealing material accommodating portions 84, 84 and enters one of the pair of pipe end accommodating portions 82, 82.

[0061] The end of the pipe 200 that has entered one of the pair of pipe end accommodating sections 82, 82 hits one of the pair of entry direction correction tubes 50, 50. Figure 8 is a diagram showing the interior of the fitting body 40 in this state. As the end of the pipe 200 continues to advance, the entry direction correction tube 50 is pushed into the pipe end accommodating section 82.

[0062] As the entry direction correcting tube 50 is pushed into the pipe end accommodating portion 82, one end of the pipe 200 penetrates the sealing material 42. As the one end of the pipe 200 advances through the fitting body 40, the one end of the pipe 200 expands the sealing material 42 from its inner periphery outward in the radial direction. Figure 9 is a diagram showing the interior of the fitting body 40 in a state in which the sealing material 42 has expanded from its inner periphery outward in the radial direction. As is clear from Figure 9, as the one end of the pipe 200 penetrates the sealing material 42 and expands it from its inner periphery outward in the radial direction, the sealing material 42 is pressed against the inner circumferential surface of the sealing material accommodating portion 84.

[0063] Once one end of the pipe 200 has advanced sufficiently through the joint flow passage forming portion 60 , the operator engages the internal threads 102 of the nut 44 with the external threads 62 disposed on one end of the joint flow passage forming portion 60 .

[0064] As the worker continues to screw the female threads 102 of the nut 44 into the male threads 62 of the joint body 40, the engaging recesses 104 facing each engaging protrusion 48 change sequentially. Accordingly, the distance between the engaging protrusion 48 and the opposing engaging recess 104 gradually decreases. Figure 10 is a diagram showing the state in which the engaging protrusion 48 and the engaging recess 104 are gradually decreasing in size.

[0065] As the engaging protrusion 48 and the engaging recess 104 approach each other, the covering portion 108 of the nut 44 approaches the index portion 132 of the accommodating portion 46. Next, the covering portion 108 gradually covers the index portion 132. As a result, the covering portion 108 gradually becomes invisible from the outside of the pipe fitting 20.

[0066] Thereafter, when the covering portion 108 is no longer visible from the outside of the pipe fitting 20, the engaging protrusion 48 fits into a certain engaging recess 104. As a result, one of the pair of pipes 200, 200 is connected to the pipe fitting 20 of this embodiment. This also results in the engaging enlarged diameter portion 222 being engaged with the interior of the pipe fitting 20. The seal opposing portion 224 is positioned within the fitting body 40. Furthermore, in this way, it becomes easier to perceive that the nut 44 has been tightened completely.

[0067] Next, the worker similarly connects the other of the pair of pipes 200, 200 to the pipe joint 20. When this connection is complete, the connection between the pair of pipes 200, 200 and the pipe joint 20 according to this embodiment is complete.

[0068] [Explanation of Effects According to This Embodiment] As described above, according to the pipe fitting 20 of this embodiment, the loosening of the nut 44 can be easily prevented, and the completion of tightening of the nut 44 can be more easily perceived.

[0069] [Variations] The embodiments disclosed herein are examples in all respects. The scope of the present invention is not limited to the above-described embodiments. Of course, various design modifications may be made to the above-described embodiments without departing from the spirit of the present invention.

[0070] For example, the nut 44 does not have to have the nut outer peripheral recess 106. There are no particular limitations on the specific form of the nut 44. Furthermore, there are no particular limitations on the specific form of the seal facing portion 224. [Explanation of symbols]

[0071] 20...Pipe fitting 40...Joint body 42...Sealing material 44...Nut 46...Storage section 48…Engagement convex portion 50…Entry direction correction tube 52...Spacer 60...Joint flow path forming portion 62...Male thread 64...Slip prevention part 80…Communication path forming part 82...Pipe end housing 84...Sealing material storage section 90...Exposed recess 100...Pipe communication holding part 102...Female thread 104...engagement recess 106...Nut outer periphery recess 108...Covering part 120...Occupied body 122...Main body engagement portion 130...Main body 132...Indicator section 134...Rotation prevention protrusion 180,182,184…center axis 200…tube 220...Pipe flow path forming part 222...Enlarged diameter part for engagement 224... Seal facing part

Claims

1. a cylindrical joint body having a male thread disposed on the outer periphery of at least one end; a nut having a female thread that engages with the male thread of the fitting body and a pipe communication holding portion that is connected to the female thread and holds the pipe so that the inside of the pipe is in communication with the inside of the fitting body, the pipe joint further includes an engaging protrusion that is disposed at a position adjacent to a root of the male thread when viewed from a tip of the male thread and that protrudes along a central axis of the male thread, The nut is at least one engaging recess facing the engaging protrusion and facing a root of the male thread when the female thread engages with the male thread of the joint body; a covering portion that faces toward the root of the male thread and is arranged to surround the central axis of the female thread when the female thread meshes with the male thread of the fitting body.

2. the pipe joint further includes an indicator portion that is positioned on the front side of a base of the engaging protrusion when viewed from the tip of the male screw, 2. The pipe joint according to claim 1, wherein the distance from the covering portion to the central axis of the female thread of the nut is longer than the distance from the indicator portion to the central axis of the male thread.

3. the covering portion is disposed outside the engagement recess when viewed from the position of the central axis of the female screw, 3. A pipe joint according to claim 2, wherein the indicator portion is disposed outside the engaging protrusion when viewed from the position of the central axis of the male thread.

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